From mulyadi.santosa at gmail.com  Mon Feb  1 03:42:57 2016
From: mulyadi.santosa at gmail.com (Mulyadi Santosa)
Date: Mon, 1 Feb 2016 15:42:57 +0700
Subject: swap test for cgroups
In-Reply-To: <CAGXs5wXyA=pi51442s+ACPnMFkT0yQ3Wy_1NvME-Tb4bx3U6YA@mail.gmail.com>
References: <CAGXs5wXyA=pi51442s+ACPnMFkT0yQ3Wy_1NvME-Tb4bx3U6YA@mail.gmail.com>
Message-ID: <CAGdaadbAH_bEKsO5q75z_ZKL0NoFm2=Au6wVT891Bn0o=7SVAg@mail.gmail.com>

On Sun, Jan 31, 2016 at 3:18 PM, Kevin Wilson <wkevils at gmail.com> wrote:
> Hi,
>
> I had tried to perform the following test according to:
> http://lxr.free-electrons.com/source/Documentation/cgroups/memcg_test.txt#L211
> mkdir /sys/fs/cgroup/memory/group1
>
> echo $$ > /sys/fs/cgroup/memory/group1/cgroup.procs

Hi...

maybe you should test with "echo 0" like mentioned in the example?

IMHO, echo $$ will yield PID of your current PID of task invocation in
bash, and I think that's different with the PID of malloc program you
ran. hence the result you saw

>
> echo 40M >  /sys/fs/cgroup/memory/group1/memory.limit_in_bytes
>
> Run a process which is a very short program, allocating 100MB:
> int main() {
> // Allocate 100 MB
>   void *mem = malloc(1024*1024*100);
>   if (mem)
>       printf("malloc is ok\n");
>   pause();
> }
>
>
> VmSize seems a bit larger than 100MB, and this seems ok, when adding
> the overhead of running a process:
> cat /proc/$$/status | grep VmSize
> VmSize:   116920 kB
>
>
>
> cat   /sys/fs/cgroup/memory/group1/memory.stat  | grep swap
> swap 0
> total_swap 0
>
> cat /proc/$$/status | grep  -i swap
> VmSwap:        0 kB
>
>
> I would expect that the swap will be 60M according to the link to the
> memcg_test.txt mentioned earlier.
>
> Any ideas ?
>
> Regards,
> Kevin
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies



-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
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From vishu.kernel at gmail.com  Mon Feb  1 04:47:59 2016
From: vishu.kernel at gmail.com (Vishwas Srivastava)
Date: Mon, 1 Feb 2016 15:17:59 +0530
Subject: Query Regarding memory alignment /access
Message-ID: <CAGM3cC4EYDVU7Ge4=9oDWW9ivbm347f-5-0=Yub9kUOXso+NLw@mail.gmail.com>

Hi All,

            I have  2 questions regarding memory access/alignment
1: can aligned/unaligned virtual address could translate to
unaligned/aligned physical address ? or
 aligned virtual --- > aligned phy and unaligned virtual --- > unaligned
phy ??
2: Since the cpu access the memory in word size, for a large buffer, (say
size N bytes where N > wordsize) isn't it sufficient for buffer to be
properly aligned if its address % WORD_SIZE == 0? rather than address % N
== 0  check?? since cpu, anyways will not access more than word size at a
time so any address which is divisible by wordsize is by default properly
aligned?

Please share your inputs.
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From nobumasa.bcc at gmail.com  Mon Feb  1 14:40:15 2016
From: nobumasa.bcc at gmail.com (Airton Ishimori)
Date: Mon, 1 Feb 2016 16:40:15 -0300
Subject: Problem with GSO
Message-ID: <CAHVg_i7cFCTAN=Dkt1jcmE_R43K32ndf3H_e12Bwfmi14JnCqw@mail.gmail.com>

Hi, everyone,

I need a help. Anyone who could give me advices or a possible way to find a
solution for my problem, would be appreciated.

I think I'm getting trouble with a bad use of GSO/GRO.
Firstly, I'm putting a piece of the dmesg output that I always get when I
make a ping between two terminals.

Command used:

ping -s 1500 10.0.0.20

PING 10.0.0.20 (10.0.0.20) 1500(1528) bytes of data.
1508 bytes from 10.0.0.20: icmp_seq=3 ttl=64 time=0.161 ms
1508 bytes from 10.0.0.20: icmp_seq=4 ttl=64 time=0.165 ms
1508 bytes from 10.0.0.20: icmp_seq=5 ttl=64 time=0.209 ms



dmesg Output:


[ 1495.678355] ------------[ cut here ]------------
[ 1495.678364] WARNING: CPU: 0 PID: 1511 at
/build/buildd/linux-lts-utopic-3.16.0/net/core/dev.c:2246
skb_warn_bad_offload+0xd0/0xd8()
[ 1495.678368] : caps=(0x00000184075b59e9, 0x0000000000000000) *len=1522
data_len=0 gso_size=1460 gso_type=0 ip_summed=0*
[ 1495.678370] Modules linked in: openvswitch(OE) veth libcrc32c bnep
rfcomm bluetooth 6lowpan_iphc snd_hda_codec_realtek snd_hda_codec_generic
snd_hda_intel snd_hda_controller snd_hda_codec snd_hwdep snd_pcm i915
snd_seq_midi snd_seq_midi_event gpio_ich snd_rawmidi snd_seq snd_seq_device
coretemp video snd_timer drm_kms_helper kvm_intel drm snd lpc_ich kvm
soundcore serio_raw i2c_algo_bit shpchp mac_hid parport_pc ppdev lp parport
psmouse pata_acpi r8169 mii [last unloaded: openvswitch]
[ 1495.678410] CPU: 0 PID: 1511 Comm: handler43 Tainted: G        W  OE
3.16.0-30-generic #40~14.04.1-Ubuntu
[ 1495.678412] Hardware name:                  /DG41AN, BIOS
ANG4110H.86A.0018.2011.0325.1148 03/25/2011
[ 1495.678415]  00000000 00000000 f6b0d944 c168b423 f6b0d984 f6b0d974
c105c2ae c191ac74
[ 1495.678421]  f6b0d9a0 000005e7 c191abfc 000008c6 c168e03e c168e03e
f3df4000 f6aef3c0
[ 1495.678428]  000005b4 f6b0d98c c105c303 00000009 f6b0d984 c191ac74
f6b0d9a0 f6b0d9e0
[ 1495.678434] Call Trace:
[ 1495.678439]  [<c168b423>] dump_stack+0x41/0x52
[ 1495.678444]  [<c105c2ae>] warn_slowpath_common+0x7e/0xa0
[ 1495.678449]  [<c168e03e>] ? skb_warn_bad_offload+0xd0/0xd8
[ 1495.678452]  [<c168e03e>] ? skb_warn_bad_offload+0xd0/0xd8
[ 1495.678456]  [<c105c303>] warn_slowpath_fmt+0x33/0x40
[ 1495.678459]  [<c168e03e>] skb_warn_bad_offload+0xd0/0xd8
[ 1495.678464]  [<c15a52b8>] __skb_gso_segment+0x78/0xb0
[ 1495.678474]  [<f8750221>] rpl__skb_gso_segment+0x81/0xc0 [*openvswitch*]
[ 1495.678481]  [<f874f922>] rpl_dev_queue_xmit+0xa2/0x140 [*openvswitch*]
[ 1495.678488]  [<f874ef35>] netdev_send+0x65/0xc0 [*openvswitch*]
[ 1495.678495]  [<f874e6b1>] ovs_vport_send+0x11/0x60 [*openvswitch*]


The ping happens after a few seconds, but when I try a ping for the first
time, usually 2 or 3 (first) packets are lost and then they keep pinging to
each other.
The delay is quite high because I'm using 'printks'.

Now, let me explain what I've been doing.

I'm basically adding a new header (8 bytes size) to the IPv4 packets which
goes between L2 and L3, similarly to VLAN.
Then, I use Open vSwich (OVS) to keep forwarding my packets. For packet
size below MTU size, I have no problem. However, the problem shows up when
I try to send a packet having a higher value than the standard MTU (1500 B).

One of the questions that I have is, how to use GSO properly? With my
understanding, I can segment larger packets before calling
*dev_queue_xmit()* or *dev_hard_start_xmit()*, or even before a device
driver specific function.

OVS has support for earlier versions of the Linux kernel. I'm using


int rpl_dev_queue_xmit(struct sk_buff *skb)
{
#undef dev_queue_xmit
int err = -ENOMEM;
bool vlan, mpls;

vlan = mpls = false;

/* Avoid traversing any VLAN tags that are present to determine if
* the ethtype is MPLS. Instead compare the mac_len (end of L2) and
* skb_network_offset() (beginning of L3) whose inequality will
* indicate the presence of an MPLS label stack. */

if (skb->mac_len != skb_network_offset(skb) && !supports_mpls_gso())
mpls = true;

if (skb_vlan_tag_present(skb) && !dev_supports_vlan_tx(skb->dev))
vlan = true;

if (vlan || mpls) {
int features;

features = netif_skb_features(skb);

if (vlan) {
if (!vlan_tso)
features &= ~(NETIF_F_TSO | NETIF_F_TSO6 |
     NETIF_F_UFO | NETIF_F_FSO);

skb = vlan_insert_tag_set_proto(skb, skb->vlan_proto,
skb_vlan_tag_get(skb));
if (unlikely(!skb))
return err;
vlan_set_tci(skb, 0);
}

/* As of v3.11 the kernel provides an mpls_features field in
* struct net_device which allows devices to advertise which
* features its supports for MPLS. This value defaults to
* NETIF_F_SG and as of v3.19.
*
* This compatibility code is intended for kernels older
* than v3.19 that do not support MPLS GSO and do not
* use mpls_features. Thus this code uses NETIF_F_SG
* directly in place of mpls_features.
*/
if (mpls)
features &= NETIF_F_SG;

if (*netif_needs_gso(skb, features)*) {
struct sk_buff *nskb;

nskb = *skb_gso_segment*(skb, features);
if (!nskb) {
if (unlikely(skb_cloned(skb) &&
   pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
goto drop;

skb_shinfo(skb)->gso_type &= ~SKB_GSO_DODGY;
goto xmit;
}

if (IS_ERR(nskb)) {
err = PTR_ERR(nskb);
goto drop;
}
consume_skb(skb);
skb = nskb;

do {
nskb = skb->next;
skb->next = NULL;
err = dev_queue_xmit(skb);
skb = nskb;
} while (skb);

return err;
}
}
xmit:
return *dev_queue_xmit(skb);*

drop:
kfree_skb(skb);
return err;
}


My initial idea was to prepare a packet before entering in the code lines
in red, but I noticed that netif_needs_gso() requires *skb->gso_size* to be
set, if I'm not making a mistake.
So, another question is, how to set GSO size properly? At first, I thought
I could use any size below MTU, but it seems that is not the case.

Besides, for the kernel to properly segment packets according to the
Ethertype, I think the kernel must be able to advance the new header, so I
modified *skb_mac_gso_segment()* and
*skb_network_protocol() *which comes after *skb_gso_segment()* in the
kernel [version 3.16 (Ubuntu)]. However, I'm still getting the same dmesg
output.

As the new header goes in the same place of VLAN, with 8 bytes between L2
and L3, when the packets are segmented, each segment will have
L2+New_Header attached to them (until where I know).
I checked skb_mac_gso_segment() and I noticed that there is a GSO segment
callback for each L3 protocol type. So, I make assumptions that GSO
actually happens for protocols above L2, I mean from L3 ahead.
My understanding is right?


Any help would be very appreciated,

Thanks a lot,

*--*Airton Ishimori
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From asharaf at tataelxsi.co.in  Tue Feb  2 01:46:33 2016
From: asharaf at tataelxsi.co.in (Asharaf P)
Date: Tue, 2 Feb 2016 06:46:33 +0000
Subject: SPI Slave Patch - Kernel Version
Message-ID: <KL1PR0401MB13847C4AC9E612BB1128A292F4DF0@KL1PR0401MB1384.apcprd04.prod.outlook.com>

Hai,

I was looking for SPI slave support and found some patches at linux-spi mailing list[1].

I am using custom branch[2] from freescale based on 3.14,  on which the above patch failed, so how can i find the base version of the above patch set, also can anyone help me to find the status of the patchset, because i didn't find it merged on any tree.

[1] : http://marc.info/?l=linux-arm-kernel&m=144320405317902&w=2
[2] : http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/log/?h=imx_3.14.38_6qp_ga

Regards 
Asharaf P
      

From sandro.stiller at elfin.de  Tue Feb  2 04:09:20 2016
From: sandro.stiller at elfin.de (Sandro Stiller)
Date: Tue, 2 Feb 2016 10:09:20 +0100
Subject: How to find a bug with lost network messages
Message-ID: <56B07240.8070409@elfin.de>

Hello,

I'm struggeling with a network driver (sllin[1]) which is not in the 
official kernel.
It has a lot in common with the slcan driver but is used for LIN networks.
The problem is, that sometimes messages sent to the network layer via 
netif_rx() don't arrive in all listening programs.

This is how the driver works:
1. The application sends CAN messages to the network interface
2. The driver forwards it to the UART (tty)
3. The UART receives the same message (single-wire connection, RX and TX 
connected) and sends it back to the network layer
4. The sending application receives the previously sent message and can 
check for transmission errors and appended LIN slave replies.

Sometimes the last point (4.) does not work after 10 - 40 seconds of 
transmission.
The application does not receive the message using a blocking read() on 
the socket, but other processes receive it (running candump on the 
interface). netif_rx() always returns 0.

If more programs are listening (running multiple instances of candump), 
the problem appears less often or never.
On my PC there is no problem, it occures on ARM only.
I'm using kernel 4.1.

Can you give me a hint where to search for the cause of this behaviour?

Thank you very much.

Sandro


[1]: https://github.com/sstiller/sllin/tree/master/sllin


From a.pichlkostner at gmx.de  Tue Feb  2 14:05:58 2016
From: a.pichlkostner at gmx.de (Arthur Pichlkostner)
Date: Tue, 2 Feb 2016 20:05:58 +0100
Subject: How to find a bug with lost network messages
In-Reply-To: <56B07240.8070409@elfin.de>
References: <56B07240.8070409@elfin.de>
Message-ID: <20160202190558.GA1881@debi5.lan>


I just know that netif_rx() should be updated to netif_rx_ni() for newer kernels.
Without the change I had NOHZ errors in the log, the same change was done in SLCAN.
Maybe this is the origin of your problem.

You can try our fork on https://github.com/tjohann/sllin which includes many improvents and fixes compared to the original driver from 2013.

On Tue, Feb 02, 2016 at 10:09:20AM +0100, Sandro Stiller wrote:
> Hello,
> 
> I'm struggeling with a network driver (sllin[1]) which is not in the 
> official kernel.
> It has a lot in common with the slcan driver but is used for LIN networks.
> The problem is, that sometimes messages sent to the network layer via 
> netif_rx() don't arrive in all listening programs.
> 
> This is how the driver works:
> 1. The application sends CAN messages to the network interface
> 2. The driver forwards it to the UART (tty)
> 3. The UART receives the same message (single-wire connection, RX and TX 
> connected) and sends it back to the network layer
> 4. The sending application receives the previously sent message and can 
> check for transmission errors and appended LIN slave replies.
> 
> Sometimes the last point (4.) does not work after 10 - 40 seconds of 
> transmission.
> The application does not receive the message using a blocking read() on 
> the socket, but other processes receive it (running candump on the 
> interface). netif_rx() always returns 0.
> 
> If more programs are listening (running multiple instances of candump), 
> the problem appears less often or never.
> On my PC there is no problem, it occures on ARM only.
> I'm using kernel 4.1.
> 
> Can you give me a hint where to search for the cause of this behaviour?
> 
> Thank you very much.
> 
> Sandro
> 
> 
> [1]: https://github.com/sstiller/sllin/tree/master/sllin
> 
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies


From ranshalit at gmail.com  Fri Feb  5 03:53:51 2016
From: ranshalit at gmail.com (Ran Shalit)
Date: Fri, 5 Feb 2016 10:53:51 +0200
Subject: dma_alloc_coherent
Message-ID: <CAJ2oMhKhZNOqa5zG7dG2DKD4B+NF4TXa=Oq2tsgeSLuLiEbe3w@mail.gmail.com>

Hello,

I read the readme about dma API, but still don't understand how it
should be used
It is said that dma_alloc_coherent is responsible for allocating the buffer.

1. But how to trigger the dma transaction to start ?
2. Is there a callback when it is finished ?

Thank you,
Ran


From kirjanov at gmail.com  Fri Feb  5 04:15:33 2016
From: kirjanov at gmail.com (Denis Kirjanov)
Date: Fri, 5 Feb 2016 12:15:33 +0300
Subject: dma_alloc_coherent
In-Reply-To: <CAJ2oMhKhZNOqa5zG7dG2DKD4B+NF4TXa=Oq2tsgeSLuLiEbe3w@mail.gmail.com>
References: <CAJ2oMhKhZNOqa5zG7dG2DKD4B+NF4TXa=Oq2tsgeSLuLiEbe3w@mail.gmail.com>
Message-ID: <CAHj3AVkKAMTNJqMCOrBCDo1KuL9nVxq=uSUo7qFbu3tMb4+UFA@mail.gmail.com>

On 2/5/16, Ran Shalit <ranshalit at gmail.com> wrote:
> Hello,
>
> I read the readme about dma API, but still don't understand how it
> should be used
> It is said that dma_alloc_coherent is responsible for allocating the
> buffer.

>
> 1. But how to trigger the dma transaction to start ?
> 2. Is there a callback when it is finished ?

It's used for data transfer between IO device and system memory. You
allocate a kernel buffer for DMA transaction (in this case dma from
device to system memory) and setup your device for dma transfer. An IO
device usually generates an interrupt when DMA transfer completes.
>
> Thank you,
> Ran
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>


-- 
Regards / Mit besten Gr??en,
Denis


From harish.b310 at gmail.com  Fri Feb  5 13:35:19 2016
From: harish.b310 at gmail.com (Harish)
Date: Sat, 6 Feb 2016 00:05:19 +0530
Subject: Sleep_on_buffer
Message-ID: <9529508C-FA00-4F3A-8872-0EC43882C36C@gmail.com>


Hi,


    I see this(sleep_on_buffer) in the /proc/<pid>/wchan for a process, could some one help me understand what does this exactly mean? Around this time the thread was actually trying write to the console. The status of the process from /proc says "Disk Sleeping" 

   
Thanks,
Harish

From mashemat at gmail.com  Fri Feb  5 13:49:19 2016
From: mashemat at gmail.com (masoud hematpour)
Date: Fri, 5 Feb 2016 19:49:19 +0100
Subject: Memory Management
Message-ID: <CABTiFJYWkuJnV33pU9J_-Nzrt-rd5c3L_8VxBuPnExS-Za8wEA@mail.gmail.com>

Hi,

I am beginner to kernel source. I decide to work on Performance Tuning. I
studied some material around memory management but which material is well
described for Memory management in Linux?


Thank you,


masoud
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From ranshalit at gmail.com  Sat Feb  6 14:22:49 2016
From: ranshalit at gmail.com (Ran Shalit)
Date: Sat, 6 Feb 2016 21:22:49 +0200
Subject: dma_alloc_coherent
In-Reply-To: <CAHj3AVkKAMTNJqMCOrBCDo1KuL9nVxq=uSUo7qFbu3tMb4+UFA@mail.gmail.com>
References: <CAJ2oMhKhZNOqa5zG7dG2DKD4B+NF4TXa=Oq2tsgeSLuLiEbe3w@mail.gmail.com>
	<CAHj3AVkKAMTNJqMCOrBCDo1KuL9nVxq=uSUo7qFbu3tMb4+UFA@mail.gmail.com>
Message-ID: <CAJ2oMhLi9LV6QQ-Yr1yNKgoBwC_ET-qTwDAGGrDc9BGZLKNNXA@mail.gmail.com>

On Fri, Feb 5, 2016 at 11:15 AM, Denis Kirjanov <kirjanov at gmail.com> wrote:
> On 2/5/16, Ran Shalit <ranshalit at gmail.com> wrote:
>> Hello,
>>
>> I read the readme about dma API, but still don't understand how it
>> should be used
>> It is said that dma_alloc_coherent is responsible for allocating the
>> buffer.
>
>>
>> 1. But how to trigger the dma transaction to start ?
>> 2. Is there a callback when it is finished ?
>
> It's used for data transfer between IO device and system memory. You
> allocate a kernel buffer for DMA transaction (in this case dma from
> device to system memory) and setup your device for dma transfer. An IO
> device usually generates an interrupt when DMA transfer completes.
> Denis

If I understand correctly the full picture how to use dma is as
following (schematics):

buf = dma_alloc_coherent(); <<-- done once at the lifetime

every time we need to trigger dma:

//start transaction now
writeb(buf, DMA_ADDR) <<- juat an example, actually it is totally
depends on dma device
writeb(START_DMA, DMA_ADDR+2) <<- juat an example, actually it is
totally depends on dma device

//usually we also register on irq for callback on finishing the transaction.

 hope I got it all correct, if you have any comments please add.

Thanks,
Ran


From me at tobin.cc  Sun Feb  7 16:12:42 2016
From: me at tobin.cc (Tobin Harding)
Date: Mon, 8 Feb 2016 08:12:42 +1100
Subject: mkinitcpio
Message-ID: <20160207211242.GA14144@eros.fritz.box>

Hi,

I have a kernel build question please. After build and install of new kernel and
modules mkinitcpio gives the following warning

==> WARNING: No modules were added to the image. This is probably not what you
want.

Web search did not turn up anything.

Complete command and output is:

# mkinitcpio -g initramfs-custom.img -k 4.5.0-eudyptula+
==> Starting build: 4.5.0-eudyptula+
  -> Running build hook: [base]
  -> Running build hook: [udev]
  -> Running build hook: [autodetect]
  -> Running build hook: [modconf]
  -> Running build hook: [block]
  -> Running build hook: [filesystems]
  -> Running build hook: [keyboard]
  -> Running build hook: [fsck]
==> WARNING: No modules were added to the image. This is probably not what you want.
==> Creating gzip-compressed initcpio image: /boot/initramfs-custom.img
==> Image generation successful
#

Any pointers much appreciated, thank you.

Tobin
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From mkhasaw1 at binghamton.edu  Sun Feb  7 16:24:08 2016
From: mkhasaw1 at binghamton.edu (Mohammad A Khasawneh)
Date: Sun, 7 Feb 2016 16:24:08 -0500
Subject: Virtual and physical page address
Message-ID: <CALVKJd=Q26Cz3ieuxvo5r5yvfM_J=VeL_2_oADRLYS-oYQBGoA@mail.gmail.com>

Hello everyone,

I am attempting to dump the page table of a process in terms of virtual
addresses and the corresponding physical addresses. I am looking for
information whether the pointers I am using are correct for this purpose:

1. Can I say that pte_page(pte_t) returns the virtual address of the page
that the PTE points at?

2. can I say that page_to_phys(struct page) returns the physical address of
that same entry?

Thank you,
Mohammad
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From krinkin.m.u at gmail.com  Sun Feb  7 16:43:30 2016
From: krinkin.m.u at gmail.com (Mike Krinkin)
Date: Mon, 8 Feb 2016 00:43:30 +0300
Subject: Virtual and physical page address
In-Reply-To: <CALVKJd=Q26Cz3ieuxvo5r5yvfM_J=VeL_2_oADRLYS-oYQBGoA@mail.gmail.com>
References: <CALVKJd=Q26Cz3ieuxvo5r5yvfM_J=VeL_2_oADRLYS-oYQBGoA@mail.gmail.com>
Message-ID: <20160207214329.GA20374@kmu-tp-x230>

On Sun, Feb 07, 2016 at 04:24:08PM -0500, Mohammad A Khasawneh wrote:
> Hello everyone,
> 
> I am attempting to dump the page table of a process in terms of virtual
> addresses and the corresponding physical addresses. I am looking for
> information whether the pointers I am using are correct for this purpose:
> 
> 1. Can I say that pte_page(pte_t) returns the virtual address of the page
> that the PTE points at?

pte_page returns struct page pointer (virtual address of the struct page, but
i suppose it's not the virtual address you need), it has nothing to do with a
virtual address the pte corresponds to.

> 
> 2. can I say that page_to_phys(struct page) returns the physical address of
> that same entry?

page_to_phys returns physical address the struct page corresponds to, so yes.

> 
> Thank you,
> Mohammad

> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies



From pggllrd at gmail.com  Sun Feb  7 17:16:46 2016
From: pggllrd at gmail.com (Pablo G. Gallardo)
Date: Sun, 07 Feb 2016 20:16:46 -0200
Subject: mkinitcpio
In-Reply-To: <20160207211242.GA14144@eros.fritz.box>
References: <20160207211242.GA14144@eros.fritz.box>
Message-ID: <996485F3-18E9-49E5-845F-66056263B41C@gmail.com>

Em 7 de fevereiro de 2016 19:12:42 BRST, Tobin Harding <me at tobin.cc> escreveu:
>Hi,
>
>I have a kernel build question please. After build and install of new
>kernel and
>modules mkinitcpio gives the following warning
>
>==> WARNING: No modules were added to the image. This is probably not
>what you
>want.
>
>Web search did not turn up anything.
>
>Complete command and output is:
>
># mkinitcpio -g initramfs-custom.img -k 4.5.0-eudyptula+
>==> Starting build: 4.5.0-eudyptula+
>  -> Running build hook: [base]
>  -> Running build hook: [udev]
>  -> Running build hook: [autodetect]
>  -> Running build hook: [modconf]
>  -> Running build hook: [block]
>  -> Running build hook: [filesystems]
>  -> Running build hook: [keyboard]
>  -> Running build hook: [fsck]
>==> WARNING: No modules were added to the image. This is probably not
>what you want.
>==> Creating gzip-compressed initcpio image: /boot/initramfs-custom.img
>==> Image generation successful
>#
>
>Any pointers much appreciated, thank you.
>
>Tobin
>
>
>------------------------------------------------------------------------
>
>_______________________________________________
>Kernelnewbies mailing list
>Kernelnewbies at kernelnewbies.org
>http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

Hello Tobin,

Please post every step you took to build the kernel.

Thanks,
-- 
Pablo G. Gallardo


From Valdis.Kletnieks at vt.edu  Sun Feb  7 21:45:49 2016
From: Valdis.Kletnieks at vt.edu (Valdis.Kletnieks at vt.edu)
Date: Sun, 07 Feb 2016 21:45:49 -0500
Subject: mkinitcpio
In-Reply-To: <20160207211242.GA14144@eros.fritz.box>
References: <20160207211242.GA14144@eros.fritz.box>
Message-ID: <188942.1454899549@turing-police.cc.vt.edu>

On Mon, 08 Feb 2016 08:12:42 +1100, Tobin Harding said:

> ==> WARNING: No modules were added to the image. This is probably not what you want.


This may or may not be an error.  A distro kernel is usually built with
all or almost all drivers built as modules, so an init image that has no
modules in it will probably fail to boot correctly.

However, if it's a self-built kernel that has all drivers needed to get the
root filesystem mounted already built-in, it's not a real issue.

If it's intended because things are built in, your mkinitcpio probably
has a flag to tell it that it's OK (n dracut, it's --no-kernel).
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From vishu.kernel at gmail.com  Sun Feb  7 23:01:40 2016
From: vishu.kernel at gmail.com (Vishwas Srivastava)
Date: Mon, 8 Feb 2016 09:31:40 +0530
Subject: dma_alloc_coherent
Message-ID: <CAGM3cC5iYudCCuvZneTYNHLpzMz1YWoS6RUh_ff9XS9RA5jwcQ@mail.gmail.com>

Hi Ran,
             the api which you have mentioned...

void *
dma_alloc_coherent(struct device *dev, size_t size,
			     dma_addr_t *dma_handle, gfp_t flag)

is the kernel api to alloc consistent memory.

DMA devices understand the physical addresses not the virtual addresses.

which means that we must supply to the dma device, the physical address, to read

from or to write to.

The second argument of this api is an input argument which is updated
by the kernel if this api returns a success (and contains the physical base
address of the allocated memory) and the returned value of this api is the
kernel virtual address.

if the *CPU* has to operate on this memory (assume that the memory is
dma'ed by the dma device and cpu want to read it for further processing )
it should use the virtual address, so the returned value of this api, as
the base address.
However, if the dma device has to operate on this memory (assume device
want to write to this memory), it should use the *dma_handle* , which is
the physical address (base) of the dma memory.

Now the question is how the dma device knows about this *physical* address?
The answer is that the "dma controller" register would have a register to
accept this physical address.

So the sequence of steps probably would be, in your case:
1: allocate the dma memory
2: programme the dma controller register with the physical address returned
by this api, plus the size of the transaction and may be some more
registers for setting some kind of flags (depends on your dma device)
3: programme the dma controller's dma *start* bit.

after this the dma starts and dma device starts writing to the memory .


I hope, this clarifies you.




On Sun, Feb 7, 2016 at 10:30 PM, <kernelnewbies-request at kernelnewbies.org>
wrote:

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>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Kernelnewbies digest..."
>
>
> Today's Topics:
>
>    1. Re: dma_alloc_coherent (Ran Shalit)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 6 Feb 2016 21:22:49 +0200
> From: Ran Shalit <ranshalit at gmail.com>
> Subject: Re: dma_alloc_coherent
> To: Denis Kirjanov <kirjanov at gmail.com>
> Cc: kernelnewbies <kernelnewbies at kernelnewbies.org>
> Message-ID:
>         <
> CAJ2oMhLi9LV6QQ-Yr1yNKgoBwC_ET-qTwDAGGrDc9BGZLKNNXA at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> On Fri, Feb 5, 2016 at 11:15 AM, Denis Kirjanov <kirjanov at gmail.com>
> wrote:
> > On 2/5/16, Ran Shalit <ranshalit at gmail.com> wrote:
> >> Hello,
> >>
> >> I read the readme about dma API, but still don't understand how it
> >> should be used
> >> It is said that dma_alloc_coherent is responsible for allocating the
> >> buffer.
> >
> >>
> >> 1. But how to trigger the dma transaction to start ?
> >> 2. Is there a callback when it is finished ?
> >
> > It's used for data transfer between IO device and system memory. You
> > allocate a kernel buffer for DMA transaction (in this case dma from
> > device to system memory) and setup your device for dma transfer. An IO
> > device usually generates an interrupt when DMA transfer completes.
> > Denis
>
> If I understand correctly the full picture how to use dma is as
> following (schematics):
>
> buf = dma_alloc_coherent(); <<-- done once at the lifetime
>
> every time we need to trigger dma:
>
> //start transaction now
> writeb(buf, DMA_ADDR) <<- juat an example, actually it is totally
> depends on dma device
> writeb(START_DMA, DMA_ADDR+2) <<- juat an example, actually it is
> totally depends on dma device
>
> //usually we also register on irq for callback on finishing the
> transaction.
>
>  hope I got it all correct, if you have any comments please add.
>
> Thanks,
> Ran
>
>
>
> ------------------------------
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
> End of Kernelnewbies Digest, Vol 63, Issue 7
> ********************************************
>
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From ranshalit at gmail.com  Mon Feb  8 01:24:59 2016
From: ranshalit at gmail.com (Ran Shalit)
Date: Mon, 8 Feb 2016 08:24:59 +0200
Subject: dma_alloc_coherent
In-Reply-To: <CAGM3cC5iYudCCuvZneTYNHLpzMz1YWoS6RUh_ff9XS9RA5jwcQ@mail.gmail.com>
References: <CAGM3cC5iYudCCuvZneTYNHLpzMz1YWoS6RUh_ff9XS9RA5jwcQ@mail.gmail.com>
Message-ID: <CAJ2oMhJcw-7QB7aTgB16L=ZkG08Lpy60ZXERVXgbpbrEQzRe7g@mail.gmail.com>

On Mon, Feb 8, 2016 at 6:01 AM, Vishwas Srivastava
<vishu.kernel at gmail.com> wrote:
> Hi Ran,
>              the api which you have mentioned...
>
> void *
> dma_alloc_coherent(struct device *dev, size_t size,
>     dma_addr_t *dma_handle, gfp_t flag)
>
> is the kernel api to alloc consistent memory.
>
> DMA devices understand the physical addresses not the virtual addresses.
>
> which means that we must supply to the dma device, the physical address, to
> read
>
> from or to write to.
>
> The second argument of this api is an input argument which is updated
> by the kernel if this api returns a success (and contains the physical base
> address of the allocated memory) and the returned value of this api is the
> kernel virtual address.
>
> if the *CPU* has to operate on this memory (assume that the memory is dma'ed
> by the dma device and cpu want to read it for further processing ) it should
> use the virtual address, so the returned value of this api, as the base
> address.
> However, if the dma device has to operate on this memory (assume device want
> to write to this memory), it should use the *dma_handle* , which is the
> physical address (base) of the dma memory.
>
> Now the question is how the dma device knows about this *physical* address?
> The answer is that the "dma controller" register would have a register to
> accept this physical address.
>
> So the sequence of steps probably would be, in your case:
> 1: allocate the dma memory
> 2: programme the dma controller register with the physical address returned
> by this api, plus the size of the transaction and may be some more registers
> for setting some kind of flags (depends on your dma device)
> 3: programme the dma controller's dma *start* bit.
>
> after this the dma starts and dma device starts writing to the memory .
>
>
> I hope, this clarifies you.
>
>

Hi Vishwas,

That's fully clarify the questions about dma_alloc_coherent.

I also try to figure out what's the difference between
dma_alloc_coherent and dma_map_single.

I could not find and important difference between these two methods.
1. With both methods I stil need to program the dma controller with
the physical address and the start trigger.
2. I can still do the allocation whenever I want with both methods
(for example at the initialization of the driver),
3. Not sure what the actuall dma_map_single does (and if it really
necessary to use it), becuase it seems I could just translate the
virtual value from kmalloc into physical address and return it to the
dma controller.

Thank you for the time,
Ran


From saumendra.d at hcl.com  Mon Feb  8 01:59:24 2016
From: saumendra.d at hcl.com (Saumendra Dash)
Date: Mon, 8 Feb 2016 06:59:24 +0000
Subject: dma_alloc_coherent
In-Reply-To: <CAJ2oMhJcw-7QB7aTgB16L=ZkG08Lpy60ZXERVXgbpbrEQzRe7g@mail.gmail.com>
References: <CAGM3cC5iYudCCuvZneTYNHLpzMz1YWoS6RUh_ff9XS9RA5jwcQ@mail.gmail.com>
	<CAJ2oMhJcw-7QB7aTgB16L=ZkG08Lpy60ZXERVXgbpbrEQzRe7g@mail.gmail.com>
Message-ID: <C36A4BBE8B4E0943AB331761BE6FD38A175566A1@chn-hclt-mbs06.HCLT.CORP.HCL.IN>

>> Hi Ran,
>              the api which you have mentioned...
>
>> void *
>> dma_alloc_coherent(struct device *dev, size_t size,
>>     dma_addr_t *dma_handle, gfp_t flag)
>>
>> is the kernel api to alloc consistent memory.
>>
>> DMA devices understand the physical addresses not the virtual addresses.
>>
>> which means that we must supply to the dma device, the physical 
>> address, to read
>>
>> from or to write to.
>>
>> The second argument of this api is an input argument which is updated 
>> by the kernel if this api returns a success (and contains the physical 
>> base address of the allocated memory) and the returned value of this 
>> api is the kernel virtual address.
>>
>> if the *CPU* has to operate on this memory (assume that the memory is 
>> dma'ed by the dma device and cpu want to read it for further 
>> processing ) it should use the virtual address, so the returned value 
>> of this api, as the base address.
>> However, if the dma device has to operate on this memory (assume 
>> device want to write to this memory), it should use the *dma_handle* , 
>> which is the physical address (base) of the dma memory.
>>
>> Now the question is how the dma device knows about this *physical* address?
>> The answer is that the "dma controller" register would have a register 
>> to accept this physical address.
>>
>> So the sequence of steps probably would be, in your case:
>> 1: allocate the dma memory
>> 2: programme the dma controller register with the physical address 
>> returned by this api, plus the size of the transaction and may be some 
>> more registers for setting some kind of flags (depends on your dma 
>> device)
>> 3: programme the dma controller's dma *start* bit.
>>
>> after this the dma starts and dma device starts writing to the memory .

Hi Vishwas,

>That's fully clarify the questions about dma_alloc_coherent.

>I also try to figure out what's the difference between dma_alloc_coherent and dma_map_single.

>I could not find and important difference between these two methods.
>1. With both methods I stil need to program the dma controller with the physical address and the start trigger.
>2. I can still do the allocation whenever I want with both methods (for example at the initialization of the driver), 3. Not sure what the actuall dma_map_single does (and if it really necessary to use it), becuase it >seems I could just translate the virtual value from kmalloc into physical address and return it to the dma controller.

DMA transfers are done either in BURST mode or CYCLE STEALING mode.
In Burst mode, the bus is captured for the entire duration of the transfer  from the SRC to DST.  In this case, the bus will  be released when the Xfer is complete, so obviously it is not an efficient way of doing DMA.  DMA_ALLOC_COHERENT() does this way.
In Cycle Stealing mode, the DMA controller grab the bus when free, send a byte  and then free the bus immediately. This process is repeated till the Xfer is complete, it is very efficient sine the bus is not grabbed for the entire transaction to complete.  DMA_MAP_SINGLE() does this way.

 Hope this helps.

Thanks,
Saumendra


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From gtvrreddy at gmail.com  Mon Feb  8 03:08:34 2016
From: gtvrreddy at gmail.com (Ramana Reddy)
Date: Mon, 8 Feb 2016 13:38:34 +0530
Subject: TCP_REPAIR code and how it works
Message-ID: <CAL2CrsN_b0j7cPgdZw5qqa43TajbgSHGBaV+fpc9q5HUEFpNug@mail.gmail.com>

Hi All,

Any one have an idea of  hwo TCP_REPAIR works, and a working example
of a client and multiple servers.

Looking forward for your help.

Thanks & Regards,
Raman
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From me at tobin.cc  Mon Feb  8 03:30:28 2016
From: me at tobin.cc (Tobin Harding)
Date: Mon, 8 Feb 2016 19:30:28 +1100
Subject: mkinitcpio
In-Reply-To: <188942.1454899549@turing-police.cc.vt.edu>
References: <20160207211242.GA14144@eros.fritz.box>
	<188942.1454899549@turing-police.cc.vt.edu>
Message-ID: <20160208083028.GA1673@eros.fritz.box>

Issue resolved thank you. I forgot to CC the list. Thanks also to Pablo
G. Gallardo.

Regards,
Tobin Harding.
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From mudongliangabcd at gmail.com  Mon Feb  8 03:43:07 2016
From: mudongliangabcd at gmail.com (=?UTF-8?B?5oWV5Yas5Lqu?=)
Date: Mon, 8 Feb 2016 16:43:07 +0800
Subject: Memory Management
In-Reply-To: <CABTiFJYWkuJnV33pU9J_-Nzrt-rd5c3L_8VxBuPnExS-Za8wEA@mail.gmail.com>
References: <CABTiFJYWkuJnV33pU9J_-Nzrt-rd5c3L_8VxBuPnExS-Za8wEA@mail.gmail.com>
Message-ID: <CAD-N9QWR+p7WBJ4AmJ_srPhMB2pO5whqSK43Gck2dgdHkAdU6w@mail.gmail.com>

I think "Understanding The Linux Virtual Memory Manager" is a good choice.

[1] Understanding The Linux Virtual Memory Manager:
https://www.kernel.org/doc/gorman/pdf/understand.pdf

2016-02-06 2:49 GMT+08:00 masoud hematpour <mashemat at gmail.com>:

> Hi,
>
> I am beginner to kernel source. I decide to work on Performance Tuning. I
> studied some material around memory management but which material is well
> described for Memory management in Linux?
>
>
> Thank you,
>
>
> masoud
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>


-- 
My best regards to you.

     No System Is Safe!
     mudongliang
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From varyani.nitin1 at gmail.com  Mon Feb  8 03:50:44 2016
From: varyani.nitin1 at gmail.com (Nitin Varyani)
Date: Mon, 8 Feb 2016 14:20:44 +0530
Subject: Process Scheduling
Message-ID: <CAKfJ7K+yfM_ceu6V+R3wFPAekj+E7onFX4nPEDaxdYbkMs_WMA@mail.gmail.com>

Hi,
      I am new to kernel source. I want to plugin a new process scheduling
algorithm. Can someone elaborate the steps to do it?
Nitin
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From bjorn at mork.no  Mon Feb  8 04:08:06 2016
From: bjorn at mork.no (=?utf-8?Q?Bj=C3=B8rn_Mork?=)
Date: Mon, 08 Feb 2016 10:08:06 +0100
Subject: mkinitcpio
In-Reply-To: <20160208083028.GA1673@eros.fritz.box> (Tobin Harding's message
	of "Mon, 8 Feb 2016 19:30:28 +1100")
References: <20160207211242.GA14144@eros.fritz.box>
	<188942.1454899549@turing-police.cc.vt.edu>
	<20160208083028.GA1673@eros.fritz.box>
Message-ID: <87zivb36yx.fsf@nemi.mork.no>

Tobin Harding <me at tobin.cc> writes:

> Issue resolved thank you. I forgot to CC the list. Thanks also to Pablo
> G. Gallardo.

Please give a summary of how the issue was resolved, even if it may seem
obvious to you now.  The problem was important enough for you to ask
about, and you can be sure that you are not alone. The next person
having the same problem will find your question.  A nice gesture would
be to let them find your answer as well...


Bj?rn


From sanjeevsharmaengg at gmail.com  Mon Feb  8 05:35:25 2016
From: sanjeevsharmaengg at gmail.com (sanjeev sharma)
Date: Mon, 8 Feb 2016 16:05:25 +0530
Subject: dma_alloc_coherent
In-Reply-To: <C36A4BBE8B4E0943AB331761BE6FD38A175566A1@chn-hclt-mbs06.HCLT.CORP.HCL.IN>
References: <CAGM3cC5iYudCCuvZneTYNHLpzMz1YWoS6RUh_ff9XS9RA5jwcQ@mail.gmail.com>
	<CAJ2oMhJcw-7QB7aTgB16L=ZkG08Lpy60ZXERVXgbpbrEQzRe7g@mail.gmail.com>
	<C36A4BBE8B4E0943AB331761BE6FD38A175566A1@chn-hclt-mbs06.HCLT.CORP.HCL.IN>
Message-ID: <CAGUYZuRY_qMVxecBqZBcTp1tF2c+bRiip+_meB2BTsFijE8SBQ@mail.gmail.com>

Hello Saumendra,

I would suggest you to go through the following link: 1) This will explain
need of DMA with practical scenario 2) ARM DMA Mapping with example

https://sanjeevsharmaengg.wordpress.com/2014/08/26/why-dma-required-in-linux-kernel/

http://linuxkernelhacker.blogspot.in/2014/07/arm-dma-mapping-explained.html

I hope these link will give you more confidence around understanding of DMA.

Regards
Sanjeev Sharma

On Mon, Feb 8, 2016 at 12:29 PM, Saumendra Dash <saumendra.d at hcl.com> wrote:

> >> Hi Ran,
> >              the api which you have mentioned...
> >
> >> void *
> >> dma_alloc_coherent(struct device *dev, size_t size,
> >>     dma_addr_t *dma_handle, gfp_t flag)
> >>
> >> is the kernel api to alloc consistent memory.
> >>
> >> DMA devices understand the physical addresses not the virtual addresses.
> >>
> >> which means that we must supply to the dma device, the physical
> >> address, to read
> >>
> >> from or to write to.
> >>
> >> The second argument of this api is an input argument which is updated
> >> by the kernel if this api returns a success (and contains the physical
> >> base address of the allocated memory) and the returned value of this
> >> api is the kernel virtual address.
> >>
> >> if the *CPU* has to operate on this memory (assume that the memory is
> >> dma'ed by the dma device and cpu want to read it for further
> >> processing ) it should use the virtual address, so the returned value
> >> of this api, as the base address.
> >> However, if the dma device has to operate on this memory (assume
> >> device want to write to this memory), it should use the *dma_handle* ,
> >> which is the physical address (base) of the dma memory.
> >>
> >> Now the question is how the dma device knows about this *physical*
> address?
> >> The answer is that the "dma controller" register would have a register
> >> to accept this physical address.
> >>
> >> So the sequence of steps probably would be, in your case:
> >> 1: allocate the dma memory
> >> 2: programme the dma controller register with the physical address
> >> returned by this api, plus the size of the transaction and may be some
> >> more registers for setting some kind of flags (depends on your dma
> >> device)
> >> 3: programme the dma controller's dma *start* bit.
> >>
> >> after this the dma starts and dma device starts writing to the memory .
>
> Hi Vishwas,
>
> >That's fully clarify the questions about dma_alloc_coherent.
>
> >I also try to figure out what's the difference between dma_alloc_coherent
> and dma_map_single.
>
> >I could not find and important difference between these two methods.
> >1. With both methods I stil need to program the dma controller with the
> physical address and the start trigger.
> >2. I can still do the allocation whenever I want with both methods (for
> example at the initialization of the driver), 3. Not sure what the actuall
> dma_map_single does (and if it really necessary to use it), becuase it
> >seems I could just translate the virtual value from kmalloc into physical
> address and return it to the dma controller.
>
> DMA transfers are done either in BURST mode or CYCLE STEALING mode.
> In Burst mode, the bus is captured for the entire duration of the
> transfer  from the SRC to DST.  In this case, the bus will  be released
> when the Xfer is complete, so obviously it is not an efficient way of doing
> DMA.  DMA_ALLOC_COHERENT() does this way.
> In Cycle Stealing mode, the DMA controller grab the bus when free, send a
> byte  and then free the bus immediately. This process is repeated till the
> Xfer is complete, it is very efficient sine the bus is not grabbed for the
> entire transaction to complete.  DMA_MAP_SINGLE() does this way.
>
>  Hope this helps.
>
> Thanks,
> Saumendra
>
>
> ::DISCLAIMER::
>
> ----------------------------------------------------------------------------------------------------------------------------------------------------
>
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From sanjeevsharmaengg at gmail.com  Mon Feb  8 05:38:06 2016
From: sanjeevsharmaengg at gmail.com (sanjeev sharma)
Date: Mon, 8 Feb 2016 16:08:06 +0530
Subject: Memory Management
In-Reply-To: <CAD-N9QWR+p7WBJ4AmJ_srPhMB2pO5whqSK43Gck2dgdHkAdU6w@mail.gmail.com>
References: <CABTiFJYWkuJnV33pU9J_-Nzrt-rd5c3L_8VxBuPnExS-Za8wEA@mail.gmail.com>
	<CAD-N9QWR+p7WBJ4AmJ_srPhMB2pO5whqSK43Gck2dgdHkAdU6w@mail.gmail.com>
Message-ID: <CAGUYZuQcRnBVy1FFLT2-cj6H3HmKb1RjmjQMGzm7VMy9VhdBVQ@mail.gmail.com>

Hi,

I would suggest you to go through the Linux Kernel book Robert Love which
is simpler to understand.

Regards
Sanjeev Sharma

On Mon, Feb 8, 2016 at 2:13 PM, ??? <mudongliangabcd at gmail.com> wrote:

> I think "Understanding The Linux Virtual Memory Manager" is a good choice.
>
> [1] Understanding The Linux Virtual Memory Manager:
> https://www.kernel.org/doc/gorman/pdf/understand.pdf
>
> 2016-02-06 2:49 GMT+08:00 masoud hematpour <mashemat at gmail.com>:
>
>> Hi,
>>
>> I am beginner to kernel source. I decide to work on Performance Tuning. I
>> studied some material around memory management but which material is well
>> described for Memory management in Linux?
>>
>>
>> Thank you,
>>
>>
>> masoud
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>>
>
>
> --
> My best regards to you.
>
>      No System Is Safe!
>      mudongliang
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
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From rpjday at crashcourse.ca  Mon Feb  8 06:28:29 2016
From: rpjday at crashcourse.ca (Robert P. J. Day)
Date: Mon, 08 Feb 2016 06:28:29 -0500
Subject: Memory Management
In-Reply-To: <CAGUYZuQcRnBVy1FFLT2-cj6H3HmKb1RjmjQMGzm7VMy9VhdBVQ@mail.gmail.com>
References: <CABTiFJYWkuJnV33pU9J_-Nzrt-rd5c3L_8VxBuPnExS-Za8wEA@mail.gmail.com>
	<CAD-N9QWR+p7WBJ4AmJ_srPhMB2pO5whqSK43Gck2dgdHkAdU6w@mail.gmail.com>
	<CAGUYZuQcRnBVy1FFLT2-cj6H3HmKb1RjmjQMGzm7VMy9VhdBVQ@mail.gmail.com>
Message-ID: <20160208062829.140127bmsuknda68@astoria.ccjclearline.com>

Quoting sanjeev sharma <sanjeevsharmaengg at gmail.com>:

> Hi,
>
> I would suggest you to go through the Linux Kernel book Robert Love which
> is simpler to understand.

   just a caution that that book is starting to show its age, even though
it's still really, really good. the memory management is probably still
fairly current, but i would compare all code snippets against the
current kernel just in case.

rday




From rahimi.nv at gmail.com  Mon Feb  8 07:48:57 2016
From: rahimi.nv at gmail.com (navid Rahimi)
Date: Mon, 8 Feb 2016 16:18:57 +0330
Subject: Memory Management
In-Reply-To: <20160208062829.140127bmsuknda68@astoria.ccjclearline.com>
References: <CABTiFJYWkuJnV33pU9J_-Nzrt-rd5c3L_8VxBuPnExS-Za8wEA@mail.gmail.com>
	<CAD-N9QWR+p7WBJ4AmJ_srPhMB2pO5whqSK43Gck2dgdHkAdU6w@mail.gmail.com>
	<CAGUYZuQcRnBVy1FFLT2-cj6H3HmKb1RjmjQMGzm7VMy9VhdBVQ@mail.gmail.com>
	<20160208062829.140127bmsuknda68@astoria.ccjclearline.com>
Message-ID: <CAOUBrm3-4YYtMRBPSwE=TB-13u-JxQdb34u6F+9nBa4ycqpxSQ@mail.gmail.com>

On Mon, Feb 8, 2016 at 2:58 PM, Robert P. J. Day <rpjday at crashcourse.ca> wrote:
> Quoting sanjeev sharma <sanjeevsharmaengg at gmail.com>:
>
>> Hi,
>>
>> I would suggest you to go through the Linux Kernel book Robert Love which
>> is simpler to understand.
>
>    just a caution that that book is starting to show its age, even though
> it's still really, really good. the memory management is probably still
> fairly current, but i would compare all code snippets against the
> current kernel just in case.
>
> rday

I did it, last year (almost), comparing code snippet in the book
toward kernel source there (I think it was version 3.10 or maybe 4.0,
I don't remember precisely), the code/topics is still relevant.

I am not aware of the situation for 4.14 or newer version tough.

best wishes,
-navid


From mkhasaw1 at binghamton.edu  Mon Feb  8 08:57:01 2016
From: mkhasaw1 at binghamton.edu (Mohammad A Khasawneh)
Date: Mon, 8 Feb 2016 08:57:01 -0500
Subject: Virtual and physical page address
In-Reply-To: <20160207214329.GA20374@kmu-tp-x230>
References: <CALVKJd=Q26Cz3ieuxvo5r5yvfM_J=VeL_2_oADRLYS-oYQBGoA@mail.gmail.com>
	<20160207214329.GA20374@kmu-tp-x230>
Message-ID: <CALVKJdnug5NKPq-rDYixXUR3k_qnt22CcQnrt6C29p6SQ7FyfA@mail.gmail.com>

Thank you for your answer. Is there a way to get the virtual address by
traversing the pgd->pte->page hierarchy? I'm not sure I can use the
phys_to_virt() function.

Thanks,
Mohammad
On Feb 7, 2016 16:43, "Mike Krinkin" <krinkin.m.u at gmail.com> wrote:

> On Sun, Feb 07, 2016 at 04:24:08PM -0500, Mohammad A Khasawneh wrote:
> > Hello everyone,
> >
> > I am attempting to dump the page table of a process in terms of virtual
> > addresses and the corresponding physical addresses. I am looking for
> > information whether the pointers I am using are correct for this purpose:
> >
> > 1. Can I say that pte_page(pte_t) returns the virtual address of the page
> > that the PTE points at?
>
> pte_page returns struct page pointer (virtual address of the struct page,
> but
> i suppose it's not the virtual address you need), it has nothing to do
> with a
> virtual address the pte corresponds to.
>
> >
> > 2. can I say that page_to_phys(struct page) returns the physical address
> of
> > that same entry?
>
> page_to_phys returns physical address the struct page corresponds to, so
> yes.
>
> >
> > Thank you,
> > Mohammad
>
> > _______________________________________________
> > Kernelnewbies mailing list
> > Kernelnewbies at kernelnewbies.org
> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
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From krinkin.m.u at gmail.com  Mon Feb  8 09:10:37 2016
From: krinkin.m.u at gmail.com (Mike Krinkin)
Date: Mon, 8 Feb 2016 17:10:37 +0300
Subject: Virtual and physical page address
In-Reply-To: <CALVKJdnug5NKPq-rDYixXUR3k_qnt22CcQnrt6C29p6SQ7FyfA@mail.gmail.com>
References: <CALVKJd=Q26Cz3ieuxvo5r5yvfM_J=VeL_2_oADRLYS-oYQBGoA@mail.gmail.com>
	<20160207214329.GA20374@kmu-tp-x230>
	<CALVKJdnug5NKPq-rDYixXUR3k_qnt22CcQnrt6C29p6SQ7FyfA@mail.gmail.com>
Message-ID: <20160208141037.GB20374@kmu-tp-x230>

On Mon, Feb 08, 2016 at 08:57:01AM -0500, Mohammad A Khasawneh wrote:
> Thank you for your answer. Is there a way to get the virtual address by
> traversing the pgd->pte->page hierarchy?

Well, position of pte in the hierarchy defines the virtual address, so yes,
there is way. I'm not sure that a portable across different architetures way
exists though. You can look at this reference:

https://www.kernel.org/doc/gorman/html/understand/understand006.html

> I'm not sure I can use the phys_to_virt() function.

In general you can't.

> 
> Thanks,
> Mohammad
> On Feb 7, 2016 16:43, "Mike Krinkin" <krinkin.m.u at gmail.com> wrote:
> 
> > On Sun, Feb 07, 2016 at 04:24:08PM -0500, Mohammad A Khasawneh wrote:
> > > Hello everyone,
> > >
> > > I am attempting to dump the page table of a process in terms of virtual
> > > addresses and the corresponding physical addresses. I am looking for
> > > information whether the pointers I am using are correct for this purpose:
> > >
> > > 1. Can I say that pte_page(pte_t) returns the virtual address of the page
> > > that the PTE points at?
> >
> > pte_page returns struct page pointer (virtual address of the struct page,
> > but
> > i suppose it's not the virtual address you need), it has nothing to do
> > with a
> > virtual address the pte corresponds to.
> >
> > >
> > > 2. can I say that page_to_phys(struct page) returns the physical address
> > of
> > > that same entry?
> >
> > page_to_phys returns physical address the struct page corresponds to, so
> > yes.
> >
> > >
> > > Thank you,
> > > Mohammad
> >
> > > _______________________________________________
> > > Kernelnewbies mailing list
> > > Kernelnewbies at kernelnewbies.org
> > > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >
> >


From pggllrd at gmail.com  Mon Feb  8 11:27:28 2016
From: pggllrd at gmail.com (Pablo G. Gallardo)
Date: Mon, 08 Feb 2016 14:27:28 -0200
Subject: mkinitcpio
In-Reply-To: <20160208010754.GA856@eros.fritz.box>
References: <20160207211242.GA14144@eros.fritz.box>
	<996485F3-18E9-49E5-845F-66056263B41C@gmail.com>
	<20160208010754.GA856@eros.fritz.box>
Message-ID: <4A4239A6-DFE8-4C26-99C4-D6439AB91669@gmail.com>

Em 7 de fevereiro de 2016 23:07:54 BRST, Tobin Harding <me at tobin.cc> escreveu:
>> 
>> Please post every step you took to build the kernel.
>> 
>> Thanks,
>> -- 
>> Pablo G. Gallardo
>
>Hi Pablo,
>
>Thanks for the reply. While typing out a response to you with my build
>steps I
>found the problem
>
>$ zcat /proc/config.gz > config
>
>Should have been .config
>
>Thanks again (I'm emailing you from the new running kernel!)
>
>Tobin

Hello Tobin,

Nice! I'm copying the mailing list so if anyone else has this problem, they'll know where to start looking.

Regards,
-- 
Pablo G. Gallardo


From sudipm.mukherjee at gmail.com  Mon Feb  8 12:03:14 2016
From: sudipm.mukherjee at gmail.com (Sudip Mukherjee)
Date: Mon, 8 Feb 2016 22:33:14 +0530
Subject: mkinitcpio
In-Reply-To: <20160207211242.GA14144@eros.fritz.box>
References: <20160207211242.GA14144@eros.fritz.box>
Message-ID: <CADVatmMTiqAyzoLgFFC9LBvjiW0iy1rpMNb9YKEezvGuWMu_8A@mail.gmail.com>

On Mon, Feb 8, 2016 at 2:42 AM, Tobin Harding <me at tobin.cc> wrote:
> Hi,
>
> I have a kernel build question please. After build and install of new kernel and
> modules mkinitcpio gives the following warning
>
> ==> WARNING: No modules were added to the image. This is probably not what you
> want.
>
> Web search did not turn up anything.
>
> Complete command and output is:
>
> # mkinitcpio -g initramfs-custom.img -k 4.5.0-eudyptula+

Is it a task of the Eudyptula Challenge?

Regards
Sudip


From me at tobin.cc  Tue Feb  9 00:13:23 2016
From: me at tobin.cc (me at tobin.cc)
Date: Tue, 09 Feb 2016 16:13:23 +1100
Subject: mkinitcpio
In-Reply-To: <CADVatmMTiqAyzoLgFFC9LBvjiW0iy1rpMNb9YKEezvGuWMu_8A@mail.gmail.com>
References: <20160207211242.GA14144@eros.fritz.box>
	<CADVatmMTiqAyzoLgFFC9LBvjiW0iy1rpMNb9YKEezvGuWMu_8A@mail.gmail.com>
Message-ID: <1454994803.601775.515857066.3E67DA9C@webmail.messagingengine.com>

Re-stating initial problem. I was receiving a warning when running 


From me at tobin.cc  Tue Feb  9 00:16:35 2016
From: me at tobin.cc (me at tobin.cc)
Date: Tue, 09 Feb 2016 16:16:35 +1100
Subject: mkinitcpio
In-Reply-To: <1454994803.601775.515857066.3E67DA9C@webmail.messagingengine.com>
References: <20160207211242.GA14144@eros.fritz.box>
	<CADVatmMTiqAyzoLgFFC9LBvjiW0iy1rpMNb9YKEezvGuWMu_8A@mail.gmail.com>
	<1454994803.601775.515857066.3E67DA9C@webmail.messagingengine.com>
Message-ID: <1454994995.602321.515857554.3A93FDEA@webmail.messagingengine.com>

I am glad this is the newbies list ;)

The initial problem was 

# mkinitcpio -g initramfs-custom.img -k 4.5.0-eudyptula+
==> Starting build: 4.5.0-eudyptula+
  -> Running build hook: [base]
  -> Running build hook: [udev]
  -> Running build hook: [autodetect]
  -> Running build hook: [modconf]
  -> Running build hook: [block]
  -> Running build hook: [filesystems]
  -> Running build hook: [keyboard]
  -> Running build hook: [fsck]
==> WARNING: No modules were added to the image. This is probably not
what you want.
==> Creating gzip-compressed initcpio image: /boot/initramfs-custom.img
==> Image generation successful
#

The cause of the warning turned out to be that I had built the kernel
with an 'empty' config file. 

$ zcat /proc/config > config

instead of

$ zcat /proc/config > .config
 
(note the dot on config)

If I was more experienced I would have realised this when the compile
time was so short. It was only  while replying to Pablo with the steps I
had taken to build the kernel that I noticed my error.

So, thank you to the kernelnewbies mailing list.

Regards,
Tobin Harding


From me at tobin.cc  Tue Feb  9 00:22:27 2016
From: me at tobin.cc (me at tobin.cc)
Date: Tue, 09 Feb 2016 16:22:27 +1100
Subject: mkinitcpio
In-Reply-To: <CADVatmMTiqAyzoLgFFC9LBvjiW0iy1rpMNb9YKEezvGuWMu_8A@mail.gmail.com>
References: <20160207211242.GA14144@eros.fritz.box>
	<CADVatmMTiqAyzoLgFFC9LBvjiW0iy1rpMNb9YKEezvGuWMu_8A@mail.gmail.com>
Message-ID: <1454995347.603320.515861386.57641CF1@webmail.messagingengine.com>



> Is it a task of the Eudyptula Challenge?

Hi Sudip,

Yes this was for task 3 of the  Eudyptula Challenge


From ruben at mrbrklyn.com  Tue Feb  9 00:43:22 2016
From: ruben at mrbrklyn.com (Ruben Safir)
Date: Tue, 9 Feb 2016 00:43:22 -0500
Subject: mkinitcpio
In-Reply-To: <1454994995.602321.515857554.3A93FDEA@webmail.messagingengine.com>
References: <20160207211242.GA14144@eros.fritz.box>
	<CADVatmMTiqAyzoLgFFC9LBvjiW0iy1rpMNb9YKEezvGuWMu_8A@mail.gmail.com>
	<1454994803.601775.515857066.3E67DA9C@webmail.messagingengine.com>
	<1454994995.602321.515857554.3A93FDEA@webmail.messagingengine.com>
Message-ID: <56B97C7A.7020709@mrbrklyn.com>

On 02/09/2016 12:16 AM, me at tobin.cc wrote:
> I am glad this is the newbies list ;)
> 
> The initial problem was 
> 
> # mkinitcpio -g initramfs-custom.img -k 4.5.0-eudyptula+
> ==> Starting build: 4.5.0-eudyptula+
>   -> Running build hook: [base]
>   -> Running build hook: [udev]
>   -> Running build hook: [autodetect]
>   -> Running build hook: [modconf]
>   -> Running build hook: [block]
>   -> Running build hook: [filesystems]
>   -> Running build hook: [keyboard]
>   -> Running build hook: [fsck]
> ==> WARNING: No modules were added to the image. This is probably not
> what you want.
> ==> Creating gzip-compressed initcpio image: /boot/initramfs-custom.img
> ==> Image generation successful
> #
> 
> The cause of the warning turned out to be that I had built the kernel
> with an 'empty' config file. 
> 
> $ zcat /proc/config > config
> 
> instead of
> 
> $ zcat /proc/config > .config
>  
> (note the dot on config)
> 
> If I was more experienced I would have realised this when the compile
> time was so short. It was only  while replying to Pablo with the steps I
> had taken to build the kernel that I noticed my error.
> 
> So, thank you to the kernelnewbies mailing list.
> 
> Regards,
> Tobin Harding
> 
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> 


You are not supposed to send the Challenge to the list.  It says that
like 20 times when you sign up to the list :(


-- 
So many immigrant groups have swept through our town
that Brooklyn, like Atlantis, reaches mythological
proportions in the mind of the world - RI Safir 1998
http://www.mrbrklyn.com

DRM is THEFT - We are the STAKEHOLDERS - RI Safir 2002
http://www.nylxs.com - Leadership Development in Free Software
http://www2.mrbrklyn.com/resources - Unpublished Archive
http://www.coinhangout.com - coins!
http://www.brooklyn-living.com

Being so tracked is for FARM ANIMALS and and extermination camps,
but incompatible with living as a free human being. -RI Safir 2013


From me at tobin.cc  Tue Feb  9 01:07:24 2016
From: me at tobin.cc (me at tobin.cc)
Date: Tue, 09 Feb 2016 17:07:24 +1100
Subject: mkinitcpio
In-Reply-To: <56B97C7A.7020709@mrbrklyn.com>
References: <20160207211242.GA14144@eros.fritz.box>
	<CADVatmMTiqAyzoLgFFC9LBvjiW0iy1rpMNb9YKEezvGuWMu_8A@mail.gmail.com>
	<1454994803.601775.515857066.3E67DA9C@webmail.messagingengine.com>
	<1454994995.602321.515857554.3A93FDEA@webmail.messagingengine.com>
	<56B97C7A.7020709@mrbrklyn.com>
Message-ID: <1454998044.611069.515883810.10C524BD@webmail.messagingengine.com>


I'm sorry if I have offended you, I don't believe that my question or
explanation had anything to do with the challenge. Excepting that the
work eudyptula was in the email


From ruben at mrbrklyn.com  Tue Feb  9 01:20:13 2016
From: ruben at mrbrklyn.com (Ruben Safir)
Date: Tue, 9 Feb 2016 01:20:13 -0500
Subject: mkinitcpio
In-Reply-To: <1454998044.611069.515883810.10C524BD@webmail.messagingengine.com>
References: <20160207211242.GA14144@eros.fritz.box>
	<CADVatmMTiqAyzoLgFFC9LBvjiW0iy1rpMNb9YKEezvGuWMu_8A@mail.gmail.com>
	<1454994803.601775.515857066.3E67DA9C@webmail.messagingengine.com>
	<1454994995.602321.515857554.3A93FDEA@webmail.messagingengine.com>
	<56B97C7A.7020709@mrbrklyn.com>
	<1454998044.611069.515883810.10C524BD@webmail.messagingengine.com>
Message-ID: <56B9851D.1090502@mrbrklyn.com>

On 02/09/2016 01:07 AM, me at tobin.cc wrote:
> 
> I'm sorry if I have offended you, I don't believe that my question or
> explanation had anything to do with the challenge. Excepting that the
> work eudyptula was in the email
> 
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> 


you were asked if this is from the challenge and you said yes.  Are you
trolling us or did I miss understand something?


-- 
So many immigrant groups have swept through our town
that Brooklyn, like Atlantis, reaches mythological
proportions in the mind of the world - RI Safir 1998
http://www.mrbrklyn.com

DRM is THEFT - We are the STAKEHOLDERS - RI Safir 2002
http://www.nylxs.com - Leadership Development in Free Software
http://www2.mrbrklyn.com/resources - Unpublished Archive
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http://www.brooklyn-living.com

Being so tracked is for FARM ANIMALS and and extermination camps,
but incompatible with living as a free human being. -RI Safir 2013


From me at tobin.cc  Tue Feb  9 01:27:24 2016
From: me at tobin.cc (me at tobin.cc)
Date: Tue, 09 Feb 2016 17:27:24 +1100
Subject: mkinitcpio
In-Reply-To: <56B9851D.1090502@mrbrklyn.com>
References: <20160207211242.GA14144@eros.fritz.box>
	<CADVatmMTiqAyzoLgFFC9LBvjiW0iy1rpMNb9YKEezvGuWMu_8A@mail.gmail.com>
	<1454994803.601775.515857066.3E67DA9C@webmail.messagingengine.com>
	<1454994995.602321.515857554.3A93FDEA@webmail.messagingengine.com>
	<56B97C7A.7020709@mrbrklyn.com>
	<1454998044.611069.515883810.10C524BD@webmail.messagingengine.com>
	<56B9851D.1090502@mrbrklyn.com>
Message-ID: <1454999244.614347.515891818.2FC4E80E@webmail.messagingengine.com>




> you were asked if this is from the challenge and you said yes.  Are you
> trolling us or did I miss understand something?

I'm very sorry, I in no way meant to troll. I am just honestly trying to
learn kernel development. I have two books and the afore mention
challenges as my guides. I am sorry, I miss-understood you, yes I did
answer that question. I will refrain from mentioning the challenges or
asking any questions I face while doing them in future.

Please accept my apologies, this was not the introduction to the kernel
community that I had hoped for.

Tobin Harding.


From sudipm.mukherjee at gmail.com  Tue Feb  9 02:04:02 2016
From: sudipm.mukherjee at gmail.com (Sudip Mukherjee)
Date: Tue, 9 Feb 2016 12:34:02 +0530
Subject: mkinitcpio
In-Reply-To: <1454999244.614347.515891818.2FC4E80E@webmail.messagingengine.com>
References: <20160207211242.GA14144@eros.fritz.box>
	<CADVatmMTiqAyzoLgFFC9LBvjiW0iy1rpMNb9YKEezvGuWMu_8A@mail.gmail.com>
	<1454994803.601775.515857066.3E67DA9C@webmail.messagingengine.com>
	<1454994995.602321.515857554.3A93FDEA@webmail.messagingengine.com>
	<56B97C7A.7020709@mrbrklyn.com>
	<1454998044.611069.515883810.10C524BD@webmail.messagingengine.com>
	<56B9851D.1090502@mrbrklyn.com>
	<1454999244.614347.515891818.2FC4E80E@webmail.messagingengine.com>
Message-ID: <CADVatmOvKucUTcDiN+YZ1FLoXEnkHkRf_=OM0rVW97VwF=C_bw@mail.gmail.com>

On Tue, Feb 9, 2016 at 11:57 AM,  <me at tobin.cc> wrote:
>
>
>
>> you were asked if this is from the challenge and you said yes.  Are you
>> trolling us or did I miss understand something?
>
> I'm very sorry, I in no way meant to troll. I am just honestly trying to
> learn kernel development. I have two books and the afore mention
> challenges as my guides. I am sorry, I miss-understood you, yes I did
> answer that question. I will refrain from mentioning the challenges or
> asking any questions I face while doing them in future.

little has his way of knowing if some one has asked a question regading
the challenge, and usually if some one asks then he is removed from the
challenge.

>
> Please accept my apologies, this was not the introduction to the kernel
> community that I had hoped for.

You are always welcome in the community, but the challenge rules says
"This challenge is for you, not anyone else, so don't ask about how to solve
them on mailing lists or IRC."

Regards
Sudip


From me at tobin.cc  Tue Feb  9 02:36:15 2016
From: me at tobin.cc (me at tobin.cc)
Date: Tue, 09 Feb 2016 18:36:15 +1100
Subject: mkinitcpio
In-Reply-To: <CADVatmOvKucUTcDiN+YZ1FLoXEnkHkRf_=OM0rVW97VwF=C_bw@mail.gmail.com>
References: <20160207211242.GA14144@eros.fritz.box>
	<CADVatmMTiqAyzoLgFFC9LBvjiW0iy1rpMNb9YKEezvGuWMu_8A@mail.gmail.com>
	<1454994803.601775.515857066.3E67DA9C@webmail.messagingengine.com>
	<1454994995.602321.515857554.3A93FDEA@webmail.messagingengine.com>
	<56B97C7A.7020709@mrbrklyn.com>
	<1454998044.611069.515883810.10C524BD@webmail.messagingengine.com>
	<56B9851D.1090502@mrbrklyn.com>
	<1454999244.614347.515891818.2FC4E80E@webmail.messagingengine.com>
	<CADVatmOvKucUTcDiN+YZ1FLoXEnkHkRf_=OM0rVW97VwF=C_bw@mail.gmail.com>
Message-ID: <1455003375.625719.515920490.0424B253@webmail.messagingengine.com>


> little has his way of knowing if some one has asked a question regarding
> the challenge, and usually if some one asks then he is removed from the
> challenge.

I sincerely hope that does not happen, it would be a real kick in the
teeth as far as my kernel education goes.

> You are always welcome in the community, but the challenge rules says
> "This challenge is for you, not anyone else, so don't ask about how to
> solve
> them on mailing lists or IRC."

Point noted, thank you. 

Regards,
Tobin Harding.


From alexhoppus111 at gmail.com  Tue Feb  9 13:12:23 2016
From: alexhoppus111 at gmail.com (alexhoppus)
Date: Tue, 9 Feb 2016 21:12:23 +0300
Subject: Why there is no GPU swap support in linux based systems?
Message-ID: <56BA2C07.3080409@gmail.com>

(The things below are mainly related to arm mali systems)

Hi. Actually i want to know - why there is no GPU Swap support in Linux 
based systems? It seems that the GPU works with graphical contexts in 
the same fashion as CPU handle things. I mean there are page faults, GPU 
have its own MMU, the memory used by GPU devices allocated via trivial 
page_alloc mechanism. You would say that performance is a reason, but 
there are some swap backends like zram: they use in-memory compression 
instead of disk swapping. Moreover, i think there would be a GPU data 
which could be swapped without significant drawbacks, because it 
accessed very rare.

Thank you.



From greg at kroah.com  Tue Feb  9 14:33:40 2016
From: greg at kroah.com (Greg KH)
Date: Tue, 9 Feb 2016 11:33:40 -0800
Subject: Why there is no GPU swap support in linux based systems?
In-Reply-To: <56BA2C07.3080409@gmail.com>
References: <56BA2C07.3080409@gmail.com>
Message-ID: <20160209193340.GA1912@kroah.com>

On Tue, Feb 09, 2016 at 09:12:23PM +0300, alexhoppus wrote:
> (The things below are mainly related to arm mali systems)
> 
> Hi. Actually i want to know - why there is no GPU Swap support in Linux 
> based systems? It seems that the GPU works with graphical contexts in 
> the same fashion as CPU handle things. I mean there are page faults, GPU 
> have its own MMU, the memory used by GPU devices allocated via trivial 
> page_alloc mechanism. You would say that performance is a reason, but 
> there are some swap backends like zram: they use in-memory compression 
> instead of disk swapping. Moreover, i think there would be a GPU data 
> which could be swapped without significant drawbacks, because it 
> accessed very rare.

That's not how GPU devices work.  But if you think you could help
implement this, I'm sure the graphic developers are always welcome to
working patches being sent to them for review.

best of luck,

greg k-h


From ricardo.ribalda at gmail.com  Wed Feb 10 04:05:33 2016
From: ricardo.ribalda at gmail.com (Ricardo Ribalda Delgado)
Date: Wed, 10 Feb 2016 10:05:33 +0100
Subject: Backtrace of every the threads
Message-ID: <CAPybu_0+Qj2CwQ0NeryDmqRZyFcA8JrSTfAOfTdfXsg5X2A-Ew@mail.gmail.com>

Hello

I have been debugging a process that makes a syscall which never
returned. The problem was the interaction between than process and
other kernel threads, due to an error on the way the locks were
designed (my bad).

Luckily, the error is gone now :). but I was wondering if there is a
way to show the backtrace of ALL the threads in the system, which
could have been a wonderful tool to debug this issue.

Things that I tried and NOT worked:

1) perf top:

It is fast and easy if the tasks are in active loops, but if they are
sleeping, waiting for an event, holding a lock.... they will not
appear.

2) ftrace

works, but there are MILLIONS of lines to navigate :S Unless there is
a good way to navigate the data it is a "last resource" tool.

3) gdb vmlinux /proc/kcore; info threads

I had big hopes on this... but only one thread was showed.

Are the Linux awareness gdb extensions ready?


4) sysrq, print backtrace

It only shows the active threads, not the "waiting" ones


What I want?

A magic command that shows the backtrace of ALL the threads (kernel
and userland). Something like a ps with steroids.

Does this exist? Where would be the best place to start developing
something like this: perf people, unix-utils, systemd :S , alone in a
dark basement?


Thanks!


-- 
Ricardo Ribalda


From anupam.kapoor at gmail.com  Wed Feb 10 04:20:16 2016
From: anupam.kapoor at gmail.com (Anupam Kapoor)
Date: Wed, 10 Feb 2016 14:50:16 +0530
Subject: Backtrace of every the threads
In-Reply-To: <CAPybu_0+Qj2CwQ0NeryDmqRZyFcA8JrSTfAOfTdfXsg5X2A-Ew@mail.gmail.com>
References: <CAPybu_0+Qj2CwQ0NeryDmqRZyFcA8JrSTfAOfTdfXsg5X2A-Ew@mail.gmail.com>
Message-ID: <87k2mcx6pb.fsf@fatcat.parallelwireless>


>>>>> [2016-02-10T14:35:33+0530]: "Ricardo Ribalda Delgado" (ricardo-delgado):

,----[ ricardo-delgado ]
| Luckily, the error is gone now :). but I was wondering if there is a
| way to show the backtrace of ALL the threads in the system, which
| could have been a wonderful tool to debug this issue.
`----
from the gdb info page:

In a multi-threaded program, gdb by default shows the backtrace only for
the current thread. To display the backtrace for several or all of the
threads, use the command thread apply (see thread apply). For example,
if you type thread apply all backtrace, gdb will display the backtrace
for all the threads; this is handy when you debug a core dump of a
multi-threaded program.

hope that's what you are looking for ?

--

kind regards
anupam


From ricardo.ribalda at gmail.com  Wed Feb 10 04:36:30 2016
From: ricardo.ribalda at gmail.com (Ricardo Ribalda Delgado)
Date: Wed, 10 Feb 2016 10:36:30 +0100
Subject: Backtrace of every the threads
In-Reply-To: <87k2mcx6pb.fsf@fatcat.parallelwireless>
References: <CAPybu_0+Qj2CwQ0NeryDmqRZyFcA8JrSTfAOfTdfXsg5X2A-Ew@mail.gmail.com>
	<87k2mcx6pb.fsf@fatcat.parallelwireless>
Message-ID: <CAPybu_0n87MkSQrydgzt7+ket7OgEn3FWuFmAnbuM3=Ac45J0Q@mail.gmail.com>

Hi Anupam

On Wed, Feb 10, 2016 at 10:20 AM, Anupam Kapoor <anupam.kapoor at gmail.com> wrote:
>
>
> In a multi-threaded program, gdb by default shows the backtrace only for
> the current thread. To display the backtrace for several or all of the
> threads, use the command thread apply (see thread apply). For example,
> if you type thread apply all backtrace, gdb will display the backtrace
> for all the threads; this is handy when you debug a core dump of a
> multi-threaded program.
>
> hope that's what you are looking for ?

Unfortunately not :( But thanks for trying :)

Core was generated by `BOOT_IMAGE=/boot/bzImage
root=PARTUUID=35F607FE-605D-457B-AE13-5D1099C5F266 roo'.
#0  0x0000000000000000 in irq_stack_union ()
(gdb)
(gdb)
(gdb) info  threads
  Id   Target Id         Frame
* 1    process 1         0x0000000000000000 in irq_stack_union ()
(gdb)  thread apply all backtrace
Thread 1 (process 1):
#0  0x0000000000000000 in irq_stack_union ()
#1  0x0000000000000000 in ?? ()
(gdb)


>
> --
>
> kind regards
> anupam



-- 
Ricardo Ribalda


From anupam.kapoor at gmail.com  Wed Feb 10 05:32:23 2016
From: anupam.kapoor at gmail.com (Anupam Kapoor)
Date: Wed, 10 Feb 2016 16:02:23 +0530
Subject: Backtrace of every the threads
In-Reply-To: <CAPybu_0n87MkSQrydgzt7+ket7OgEn3FWuFmAnbuM3=Ac45J0Q@mail.gmail.com>
References: <CAPybu_0+Qj2CwQ0NeryDmqRZyFcA8JrSTfAOfTdfXsg5X2A-Ew@mail.gmail.com>
	<87k2mcx6pb.fsf@fatcat.parallelwireless>
	<CAPybu_0n87MkSQrydgzt7+ket7OgEn3FWuFmAnbuM3=Ac45J0Q@mail.gmail.com>
Message-ID: <87io1wx3d4.fsf@fatcat.parallelwireless>


>>>>> [2016-02-10T15:06:30+0530]: "Ricardo Ribalda Delgado" (ricardo-delgado):
,----[ ricardo-delgado ]
| Unfortunately not :( But thanks for trying :)
`----
seems to work just fine on a trivial program here:
< aside: hopefully, i will not be judged too harshly for c++ :) >

,----
| anupam at fatcat cpu-stuff % gdb obj/affine-thread-to-cpu
| GNU gdb (GDB) 7.10.1
| Copyright (C) 2015 Free Software Foundation, Inc.
| License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
| This is free software: you are free to change and redistribute it.
| There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
| and "show warranty" for details.
| This GDB was configured as "x86_64-unknown-linux-gnu".
| Type "show configuration" for configuration details.
| For bug reporting instructions, please see:
| <http://www.gnu.org/software/gdb/bugs/>.
| Find the GDB manual and other documentation resources online at:
| <http://www.gnu.org/software/gdb/documentation/>.
| For help, type "help".
| Type "apropos word" to search for commands related to "word"...
| Reading symbols from obj/affine-thread-to-cpu...done.
| (gdb) core core.11717
| warning: core file may not match specified executable file.
| [New LWP 11717]
| [New LWP 11718]
| [New LWP 11720]
| [New LWP 11721]
| [New LWP 11719]
| warning: Could not load shared library symbols for linux-vdso.so.1.
| Do you need "set solib-search-path" or "set sysroot"?
| [Thread debugging using libthread_db enabled]
| Using host libthread_db library "/usr/lib/libthread_db.so.1".
| Core was generated by `./obj/affine-thread-to-cpu'.
| Program terminated with signal SIGSEGV, Segmentation fault.
| #0  0x00007f4a34f9170d in pthread_join () from /usr/lib/libpthread.so.0
| [Current thread is 1 (Thread 0x7f4a3536f740 (LWP 11717))]
| (gdb) thread apply all
| Please specify a command following the thread ID list
| (gdb) thread apply all bt
|
| Thread 5 (Thread 0x7f4a33b4d700 (LWP 11719)):
| #0  0x00007f4a34f9965d in nanosleep () from /usr/lib/libpthread.so.0
| #1  0x0000000000401534 in std::this_thread::sleep_for<long, std::ratio<1l, 1000l> > (__rtime=...) at /usr/include/c++/5.3.0/thread:292
| #2  <lambda()>::operator() (__closure=0x24d8de8) at affine-thread-to-cpu.cpp:27
| #3  std::_Bind_simple<main(int, char**)::<lambda()>()>::_M_invoke<> (this=0x24d8de8) at /usr/include/c++/5.3.0/functional:1531
| #4  std::_Bind_simple<main(int, char**)::<lambda()>()>::operator() (this=0x24d8de8) at /usr/include/c++/5.3.0/functional:1520
| #5  std::thread::_Impl<std::_Bind_simple<main(int, char**)::<lambda()>()> >::_M_run(void) (this=0x24d8dd0) at /usr/include/c++/5.3.0/thread:115
| #6  0x00007f4a34cbff40 in std::(anonymous namespace)::execute_native_thread_routine (__p=<optimized out>)
|     at /build/gcc/src/gcc-5.3.0/libstdc++-v3/src/c++11/thread.cc:84
| #7  0x00007f4a34f904a4 in start_thread () from /usr/lib/libpthread.so.0
| #8  0x00007f4a3443813d in clone () from /usr/lib/libc.so.6
|
| Thread 4 (Thread 0x7f4a32b4b700 (LWP 11721)):
| #0  0x00007f4a34f9965d in nanosleep () from /usr/lib/libpthread.so.0
| #1  0x0000000000401534 in std::this_thread::sleep_for<long, std::ratio<1l, 1000l> > (__rtime=...) at /usr/include/c++/5.3.0/thread:292
| #2  <lambda()>::operator() (__closure=0x24d90c8) at affine-thread-to-cpu.cpp:27
| #3  std::_Bind_simple<main(int, char**)::<lambda()>()>::_M_invoke<> (this=0x24d90c8) at /usr/include/c++/5.3.0/functional:1531
| #4  std::_Bind_simple<main(int, char**)::<lambda()>()>::operator() (this=0x24d90c8) at /usr/include/c++/5.3.0/functional:1520
| #5  std::thread::_Impl<std::_Bind_simple<main(int, char**)::<lambda()>()> >::_M_run(void) (this=0x24d90b0) at /usr/include/c++/5.3.0/thread:115
| #6  0x00007f4a34cbff40 in std::(anonymous namespace)::execute_native_thread_routine (__p=<optimized out>)
|     at /build/gcc/src/gcc-5.3.0/libstdc++-v3/src/c++11/thread.cc:84
| #7  0x00007f4a34f904a4 in start_thread () from /usr/lib/libpthread.so.0
| #8  0x00007f4a3443813d in clone () from /usr/lib/libc.so.6
|
| Thread 3 (Thread 0x7f4a3334c700 (LWP 11720)):
| #0  0x00007f4a34f9965d in nanosleep () from /usr/lib/libpthread.so.0
| #1  0x0000000000401534 in std::this_thread::sleep_for<long, std::ratio<1l, 1000l> > (__rtime=...) at /usr/include/c++/5.3.0/thread:292
| #2  <lambda()>::operator() (__closure=0x24d8f58) at affine-thread-to-cpu.cpp:27
| #3  std::_Bind_simple<main(int, char**)::<lambda()>()>::_M_invoke<> (this=0x24d8f58) at /usr/include/c++/5.3.0/functional:1531
| #4  std::_Bind_simple<main(int, char**)::<lambda()>()>::operator() (this=0x24d8f58) at /usr/include/c++/5.3.0/functional:1520
| #5  std::thread::_Impl<std::_Bind_simple<main(int, char**)::<lambda()>()> >::_M_run(void) (this=0x24d8f40) at /usr/include/c++/5.3.0/thread:115
| #6  0x00007f4a34cbff40 in std::(anonymous namespace)::execute_native_thread_routine (__p=<optimized out>)
|     at /build/gcc/src/gcc-5.3.0/libstdc++-v3/src/c++11/thread.cc:84
| #7  0x00007f4a34f904a4 in start_thread () from /usr/lib/libpthread.so.0
| #8  0x00007f4a3443813d in clone () from /usr/lib/libc.so.6
|
| Thread 2 (Thread 0x7f4a3434e700 (LWP 11718)):
| #0  0x00007f4a34f9965d in nanosleep () from /usr/lib/libpthread.so.0
| #1  0x0000000000401534 in std::this_thread::sleep_for<long, std::ratio<1l, 1000l> > (__rtime=...) at /usr/include/c++/5.3.0/thread:292
| #2  <lambda()>::operator() (__closure=0x24d8c78) at affine-thread-to-cpu.cpp:27
| #3  std::_Bind_simple<main(int, char**)::<lambda()>()>::_M_invoke<> (this=0x24d8c78) at /usr/include/c++/5.3.0/functional:1531
| #4  std::_Bind_simple<main(int, char**)::<lambda()>()>::operator() (this=0x24d8c78) at /usr/include/c++/5.3.0/functional:1520
| #5  std::thread::_Impl<std::_Bind_simple<main(int, char**)::<lambda()>()> >::_M_run(void) (this=0x24d8c60) at /usr/include/c++/5.3.0/thread:115
| #6  0x00007f4a34cbff40 in std::(anonymous namespace)::execute_native_thread_routine (__p=<optimized out>)
|     at /build/gcc/src/gcc-5.3.0/libstdc++-v3/src/c++11/thread.cc:84
| #7  0x00007f4a34f904a4 in start_thread () from /usr/lib/libpthread.so.0
| #8  0x00007f4a3443813d in clone () from /usr/lib/libc.so.6
|
| Thread 1 (Thread 0x7f4a3536f740 (LWP 11717)):
| #0  0x00007f4a34f9170d in pthread_join () from /usr/lib/libpthread.so.0
| #1  0x00007f4a34cbfe57 in __gthread_join (__value_ptr=0x0, __threadid=<optimized out>)
|     at /build/gcc/src/gcc-build/x86_64-unknown-linux-gnu/libstdc++-v3/include/x86_64-unknown-linux-gnu/bits/gthr-default.h:668
| #2  std::thread::join (this=this at entry=0x24d8c20) at /build/gcc/src/gcc-5.3.0/libstdc++-v3/src/c++11/thread.cc:107
| #3  0x0000000000401248 in main (argc=<optimized out>, argv=<optimized out>) at affine-thread-to-cpu.cpp:45
| (gdb)
|
`----

--

kind regards
anupam


From ricardo.ribalda at gmail.com  Wed Feb 10 05:56:40 2016
From: ricardo.ribalda at gmail.com (Ricardo Ribalda Delgado)
Date: Wed, 10 Feb 2016 11:56:40 +0100
Subject: Backtrace of every the threads
In-Reply-To: <87io1wx3d4.fsf@fatcat.parallelwireless>
References: <CAPybu_0+Qj2CwQ0NeryDmqRZyFcA8JrSTfAOfTdfXsg5X2A-Ew@mail.gmail.com>
	<87k2mcx6pb.fsf@fatcat.parallelwireless>
	<CAPybu_0n87MkSQrydgzt7+ket7OgEn3FWuFmAnbuM3=Ac45J0Q@mail.gmail.com>
	<87io1wx3d4.fsf@fatcat.parallelwireless>
Message-ID: <CAPybu_0xo1jF0UQnHcHfF0w=KBdUJB5U2D0=bEnaQhSUjhuDiQ@mail.gmail.com>

I did not explain myself well.

By thread I mean kernel thread, and user thread.

What i want to get is a back trace of ALL the programs running in user
and kernel space.

Your example is a single program, and the trace ends in userspace.


Sorry for the missunderstunding.

On Wed, Feb 10, 2016 at 11:32 AM, Anupam Kapoor <anupam.kapoor at gmail.com> wrote:
>
>>>>>> [2016-02-10T15:06:30+0530]: "Ricardo Ribalda Delgado" (ricardo-delgado):
> ,----[ ricardo-delgado ]
> | Unfortunately not :( But thanks for trying :)
> `----
> seems to work just fine on a trivial program here:
> < aside: hopefully, i will not be judged too harshly for c++ :) >
>
> ,----
> | anupam at fatcat cpu-stuff % gdb obj/affine-thread-to-cpu
> | GNU gdb (GDB) 7.10.1
> | Copyright (C) 2015 Free Software Foundation, Inc.
> | License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
> | This is free software: you are free to change and redistribute it.
> | There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
> | and "show warranty" for details.
> | This GDB was configured as "x86_64-unknown-linux-gnu".
> | Type "show configuration" for configuration details.
> | For bug reporting instructions, please see:
> | <http://www.gnu.org/software/gdb/bugs/>.
> | Find the GDB manual and other documentation resources online at:
> | <http://www.gnu.org/software/gdb/documentation/>.
> | For help, type "help".
> | Type "apropos word" to search for commands related to "word"...
> | Reading symbols from obj/affine-thread-to-cpu...done.
> | (gdb) core core.11717
> | warning: core file may not match specified executable file.
> | [New LWP 11717]
> | [New LWP 11718]
> | [New LWP 11720]
> | [New LWP 11721]
> | [New LWP 11719]
> | warning: Could not load shared library symbols for linux-vdso.so.1.
> | Do you need "set solib-search-path" or "set sysroot"?
> | [Thread debugging using libthread_db enabled]
> | Using host libthread_db library "/usr/lib/libthread_db.so.1".
> | Core was generated by `./obj/affine-thread-to-cpu'.
> | Program terminated with signal SIGSEGV, Segmentation fault.
> | #0  0x00007f4a34f9170d in pthread_join () from /usr/lib/libpthread.so.0
> | [Current thread is 1 (Thread 0x7f4a3536f740 (LWP 11717))]
> | (gdb) thread apply all
> | Please specify a command following the thread ID list
> | (gdb) thread apply all bt
> |
> | Thread 5 (Thread 0x7f4a33b4d700 (LWP 11719)):
> | #0  0x00007f4a34f9965d in nanosleep () from /usr/lib/libpthread.so.0
> | #1  0x0000000000401534 in std::this_thread::sleep_for<long, std::ratio<1l, 1000l> > (__rtime=...) at /usr/include/c++/5.3.0/thread:292
> | #2  <lambda()>::operator() (__closure=0x24d8de8) at affine-thread-to-cpu.cpp:27
> | #3  std::_Bind_simple<main(int, char**)::<lambda()>()>::_M_invoke<> (this=0x24d8de8) at /usr/include/c++/5.3.0/functional:1531
> | #4  std::_Bind_simple<main(int, char**)::<lambda()>()>::operator() (this=0x24d8de8) at /usr/include/c++/5.3.0/functional:1520
> | #5  std::thread::_Impl<std::_Bind_simple<main(int, char**)::<lambda()>()> >::_M_run(void) (this=0x24d8dd0) at /usr/include/c++/5.3.0/thread:115
> | #6  0x00007f4a34cbff40 in std::(anonymous namespace)::execute_native_thread_routine (__p=<optimized out>)
> |     at /build/gcc/src/gcc-5.3.0/libstdc++-v3/src/c++11/thread.cc:84
> | #7  0x00007f4a34f904a4 in start_thread () from /usr/lib/libpthread.so.0
> | #8  0x00007f4a3443813d in clone () from /usr/lib/libc.so.6
> |
> | Thread 4 (Thread 0x7f4a32b4b700 (LWP 11721)):
> | #0  0x00007f4a34f9965d in nanosleep () from /usr/lib/libpthread.so.0
> | #1  0x0000000000401534 in std::this_thread::sleep_for<long, std::ratio<1l, 1000l> > (__rtime=...) at /usr/include/c++/5.3.0/thread:292
> | #2  <lambda()>::operator() (__closure=0x24d90c8) at affine-thread-to-cpu.cpp:27
> | #3  std::_Bind_simple<main(int, char**)::<lambda()>()>::_M_invoke<> (this=0x24d90c8) at /usr/include/c++/5.3.0/functional:1531
> | #4  std::_Bind_simple<main(int, char**)::<lambda()>()>::operator() (this=0x24d90c8) at /usr/include/c++/5.3.0/functional:1520
> | #5  std::thread::_Impl<std::_Bind_simple<main(int, char**)::<lambda()>()> >::_M_run(void) (this=0x24d90b0) at /usr/include/c++/5.3.0/thread:115
> | #6  0x00007f4a34cbff40 in std::(anonymous namespace)::execute_native_thread_routine (__p=<optimized out>)
> |     at /build/gcc/src/gcc-5.3.0/libstdc++-v3/src/c++11/thread.cc:84
> | #7  0x00007f4a34f904a4 in start_thread () from /usr/lib/libpthread.so.0
> | #8  0x00007f4a3443813d in clone () from /usr/lib/libc.so.6
> |
> | Thread 3 (Thread 0x7f4a3334c700 (LWP 11720)):
> | #0  0x00007f4a34f9965d in nanosleep () from /usr/lib/libpthread.so.0
> | #1  0x0000000000401534 in std::this_thread::sleep_for<long, std::ratio<1l, 1000l> > (__rtime=...) at /usr/include/c++/5.3.0/thread:292
> | #2  <lambda()>::operator() (__closure=0x24d8f58) at affine-thread-to-cpu.cpp:27
> | #3  std::_Bind_simple<main(int, char**)::<lambda()>()>::_M_invoke<> (this=0x24d8f58) at /usr/include/c++/5.3.0/functional:1531
> | #4  std::_Bind_simple<main(int, char**)::<lambda()>()>::operator() (this=0x24d8f58) at /usr/include/c++/5.3.0/functional:1520
> | #5  std::thread::_Impl<std::_Bind_simple<main(int, char**)::<lambda()>()> >::_M_run(void) (this=0x24d8f40) at /usr/include/c++/5.3.0/thread:115
> | #6  0x00007f4a34cbff40 in std::(anonymous namespace)::execute_native_thread_routine (__p=<optimized out>)
> |     at /build/gcc/src/gcc-5.3.0/libstdc++-v3/src/c++11/thread.cc:84
> | #7  0x00007f4a34f904a4 in start_thread () from /usr/lib/libpthread.so.0
> | #8  0x00007f4a3443813d in clone () from /usr/lib/libc.so.6
> |
> | Thread 2 (Thread 0x7f4a3434e700 (LWP 11718)):
> | #0  0x00007f4a34f9965d in nanosleep () from /usr/lib/libpthread.so.0
> | #1  0x0000000000401534 in std::this_thread::sleep_for<long, std::ratio<1l, 1000l> > (__rtime=...) at /usr/include/c++/5.3.0/thread:292
> | #2  <lambda()>::operator() (__closure=0x24d8c78) at affine-thread-to-cpu.cpp:27
> | #3  std::_Bind_simple<main(int, char**)::<lambda()>()>::_M_invoke<> (this=0x24d8c78) at /usr/include/c++/5.3.0/functional:1531
> | #4  std::_Bind_simple<main(int, char**)::<lambda()>()>::operator() (this=0x24d8c78) at /usr/include/c++/5.3.0/functional:1520
> | #5  std::thread::_Impl<std::_Bind_simple<main(int, char**)::<lambda()>()> >::_M_run(void) (this=0x24d8c60) at /usr/include/c++/5.3.0/thread:115
> | #6  0x00007f4a34cbff40 in std::(anonymous namespace)::execute_native_thread_routine (__p=<optimized out>)
> |     at /build/gcc/src/gcc-5.3.0/libstdc++-v3/src/c++11/thread.cc:84
> | #7  0x00007f4a34f904a4 in start_thread () from /usr/lib/libpthread.so.0
> | #8  0x00007f4a3443813d in clone () from /usr/lib/libc.so.6
> |
> | Thread 1 (Thread 0x7f4a3536f740 (LWP 11717)):
> | #0  0x00007f4a34f9170d in pthread_join () from /usr/lib/libpthread.so.0
> | #1  0x00007f4a34cbfe57 in __gthread_join (__value_ptr=0x0, __threadid=<optimized out>)
> |     at /build/gcc/src/gcc-build/x86_64-unknown-linux-gnu/libstdc++-v3/include/x86_64-unknown-linux-gnu/bits/gthr-default.h:668
> | #2  std::thread::join (this=this at entry=0x24d8c20) at /build/gcc/src/gcc-5.3.0/libstdc++-v3/src/c++11/thread.cc:107
> | #3  0x0000000000401248 in main (argc=<optimized out>, argv=<optimized out>) at affine-thread-to-cpu.cpp:45
> | (gdb)
> |
> `----
>
> --
>
> kind regards
> anupam



-- 
Ricardo Ribalda


From anupam.kapoor at gmail.com  Wed Feb 10 05:59:57 2016
From: anupam.kapoor at gmail.com (Anupam Kapoor)
Date: Wed, 10 Feb 2016 16:29:57 +0530
Subject: Backtrace of every the threads
In-Reply-To: <CAPybu_0xo1jF0UQnHcHfF0w=KBdUJB5U2D0=bEnaQhSUjhuDiQ@mail.gmail.com>
References: <CAPybu_0+Qj2CwQ0NeryDmqRZyFcA8JrSTfAOfTdfXsg5X2A-Ew@mail.gmail.com>
	<87k2mcx6pb.fsf@fatcat.parallelwireless>
	<CAPybu_0n87MkSQrydgzt7+ket7OgEn3FWuFmAnbuM3=Ac45J0Q@mail.gmail.com>
	<87io1wx3d4.fsf@fatcat.parallelwireless>
	<CAPybu_0xo1jF0UQnHcHfF0w=KBdUJB5U2D0=bEnaQhSUjhuDiQ@mail.gmail.com>
Message-ID: <87h9hgx236.fsf@fatcat.parallelwireless>


>>>>> [2016-02-10T16:26:40+0530]: "Ricardo Ribalda Delgado" (ricardo-delgado):
,----[ ricardo-delgado ]
| By thread I mean kernel thread, and user thread.
|
| What i want to get is a back trace of ALL the programs running in user
| and kernel space.
`----
d.u.d.e :)
<backs away slowly>

--
kind regards
anupam


From Valdis.Kletnieks at vt.edu  Wed Feb 10 08:37:06 2016
From: Valdis.Kletnieks at vt.edu (Valdis.Kletnieks at vt.edu)
Date: Wed, 10 Feb 2016 08:37:06 -0500
Subject: Backtrace of every the threads
In-Reply-To: <CAPybu_0xo1jF0UQnHcHfF0w=KBdUJB5U2D0=bEnaQhSUjhuDiQ@mail.gmail.com>
References: <CAPybu_0+Qj2CwQ0NeryDmqRZyFcA8JrSTfAOfTdfXsg5X2A-Ew@mail.gmail.com>
	<87k2mcx6pb.fsf@fatcat.parallelwireless>
	<CAPybu_0n87MkSQrydgzt7+ket7OgEn3FWuFmAnbuM3=Ac45J0Q@mail.gmail.com>
	<87io1wx3d4.fsf@fatcat.parallelwireless>
	<CAPybu_0xo1jF0UQnHcHfF0w=KBdUJB5U2D0=bEnaQhSUjhuDiQ@mail.gmail.com>
Message-ID: <55546.1455111426@turing-police.cc.vt.edu>

On Wed, 10 Feb 2016 11:56:40 +0100, Ricardo Ribalda Delgado said:
> I did not explain myself well.
>
> By thread I mean kernel thread, and user thread.
>
> What i want to get is a back trace of ALL the programs running in user
> and kernel space.

See what happens when you do 'echo t > /proc/sysrq-trigger'.

Note that you probably *don't* actually want a trace of *all* tasks (hint -
what happens on a large system that has 2,000 cores on it)?

What problem are you trying to solve by getting a trace of everything? (Hint -
what meaning does a userspace stack traceback have if you're looking at
the corresponding kernel stack trace?)
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From victordetoni at gmail.com  Wed Feb 10 08:40:44 2016
From: victordetoni at gmail.com (Victor Detoni)
Date: Wed, 10 Feb 2016 11:40:44 -0200
Subject: Question about memory in C
Message-ID: <CANpwN=u71yvBSc8B7y5D3zVs1=AYNo_jbOMPQPEkHsmqx9HEHw@mail.gmail.com>

Hi all,

I'm working for a network security prototype and I would like to know the
best way to read diferent configs from the memory, for example:

My program will receive many pkts from network interface and it needs to
know what's profile it will use based on source ip address.

First all, I'm thinking to use array in C, for example:

for (i=0;i<=PROFILES;i++) {
    if (pkt.ip_addr == source_ip[i])
        do_something(pkt,i)
}

I will process at about millions entries per second and ~100 profiles. What
do you think? It will work fine? fast? any suggest?

thanks
Victor
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From skmprabhu2 at gmail.com  Wed Feb 10 08:54:12 2016
From: skmprabhu2 at gmail.com (Skm Prabhu)
Date: Wed, 10 Feb 2016 19:24:12 +0530
Subject: Question about memory in C
In-Reply-To: <CANpwN=u71yvBSc8B7y5D3zVs1=AYNo_jbOMPQPEkHsmqx9HEHw@mail.gmail.com>
References: <CANpwN=u71yvBSc8B7y5D3zVs1=AYNo_jbOMPQPEkHsmqx9HEHw@mail.gmail.com>
Message-ID: <CAOxBoUApqseFYL=GQO81DNt2ZKF+y5iU1O6M88vsfe4oqmFj+g@mail.gmail.com>

I think reading file sequentially & process it is a good idea for huge
chunk of data. Just think about sort the data in someway (i feel, index
sort or hashing would be great) & use some search mechanism. Again it is
all depends on sort & search algorithm.

On Wed, Feb 10, 2016 at 7:10 PM, Victor Detoni <victordetoni at gmail.com>
wrote:

> Hi all,
>
> I'm working for a network security prototype and I would like to know the
> best way to read diferent configs from the memory, for example:
>
> My program will receive many pkts from network interface and it needs to
> know what's profile it will use based on source ip address.
>
> First all, I'm thinking to use array in C, for example:
>
> for (i=0;i<=PROFILES;i++) {
>     if (pkt.ip_addr == source_ip[i])
>         do_something(pkt,i)
> }
>
> I will process at about millions entries per second and ~100 profiles.
> What do you think? It will work fine? fast? any suggest?
>
> thanks
> Victor
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
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From alexhoppus111 at gmail.com  Wed Feb 10 13:37:23 2016
From: alexhoppus111 at gmail.com (alexhoppus)
Date: Wed, 10 Feb 2016 21:37:23 +0300
Subject: Why there is no GPU swap support in linux based systems?
In-Reply-To: <20160209193340.GA1912@kroah.com>
References: <56BA2C07.3080409@gmail.com> <20160209193340.GA1912@kroah.com>
Message-ID: <56BB8363.1000009@gmail.com>

On 09.02.2016 22:33, Greg KH wrote:
> On Tue, Feb 09, 2016 at 09:12:23PM +0300, alexhoppus wrote:
>> (The things below are mainly related to arm mali systems)
>>
>> Hi. Actually i want to know - why there is no GPU Swap support in Linux
>> based systems? It seems that the GPU works with graphical contexts in
>> the same fashion as CPU handle things. I mean there are page faults, GPU
>> have its own MMU, the memory used by GPU devices allocated via trivial
>> page_alloc mechanism. You would say that performance is a reason, but
>> there are some swap backends like zram: they use in-memory compression
>> instead of disk swapping. Moreover, i think there would be a GPU data
>> which could be swapped without significant drawbacks, because it
>> accessed very rare.
> That's not how GPU devices work.  But if you think you could help
> implement this, I'm sure the graphic developers are always welcome to
> working patches being sent to them for review.
>
> best of luck,
>
> greg k-h
>
Could you (anyone), please, explain what exactly is wrong with this?
I'am not talking about discrete video cards. As i understand, in this case
video memory is a subset of pages from main memory. Also i will highlight
that i'am talking about swapping out some GPU related data f.e. textures,
for tasks which are not active at the moment (background graphical 
contexts).
As i see both CPU and GPU can handle page faults for graphical memory pages
and we can establish apropriate CPU and GPU mappings for this pages. So what
is the problem with this then?

Thanks for response.


From maitysanchayan at gmail.com  Wed Feb 10 14:14:35 2016
From: maitysanchayan at gmail.com (maitysanchayan at gmail.com)
Date: Thu, 11 Feb 2016 00:44:35 +0530
Subject: SPI Slave Patch - Kernel Version
In-Reply-To: <KL1PR0401MB13847C4AC9E612BB1128A292F4DF0@KL1PR0401MB1384.apcprd04.prod.outlook.com>
References: <KL1PR0401MB13847C4AC9E612BB1128A292F4DF0@KL1PR0401MB1384.apcprd04.prod.outlook.com>
Message-ID: <20160210191434.GA21297@Sanchayan-Arch>

Hi,

On 16-02-02 06:46:33, Asharaf P wrote:
> Hai,
> 
> I was looking for SPI slave support and found some patches at linux-spi mailing list[1].
> 
> I am using custom branch[2] from freescale based on 3.14,  on which the above patch failed, so how can i find the base version of the above patch set, also can anyone help me to find the status of the patchset, because i didn't find it merged on any tree.

I guess this is the sixth version of the patchset
https://lkml.org/lkml/2015/12/8/47

and there was of course a third
http://thread.gmane.org/gmane.linux.kernel.spi.devel/22130/focus=22237

AFAICT a seventh version has not been posted yet and so not merged. Since
this is a recent patchset from 2015 this is probably based on one of the
latest 4.x series kernel. Mostly you will have to backport.

Regards,
Sanchayan.


> 
> [1] : http://marc.info/?l=linux-arm-kernel&m=144320405317902&w=2
> [2] : http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/log/?h=imx_3.14.38_6qp_ga
> 
> Regards 
> Asharaf P
>       
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies


From cakturk at gmail.com  Wed Feb 10 16:25:53 2016
From: cakturk at gmail.com (Cihangir Akturk)
Date: Wed, 10 Feb 2016 23:25:53 +0200
Subject: Question about memory in C
In-Reply-To: <CANpwN=u71yvBSc8B7y5D3zVs1=AYNo_jbOMPQPEkHsmqx9HEHw@mail.gmail.com>
References: <CANpwN=u71yvBSc8B7y5D3zVs1=AYNo_jbOMPQPEkHsmqx9HEHw@mail.gmail.com>
Message-ID: <20160210212553.GA8415@portege>

On Wed, Feb 10, 2016 at 11:40:44AM -0200, Victor Detoni wrote:
> Hi all,
> 
> I'm working for a network security prototype and I would like to know the
> best way to read diferent configs from the memory, for example:
> 
> My program will receive many pkts from network interface and it needs to
> know what's profile it will use based on source ip address.
> 
> First all, I'm thinking to use array in C, for example:
> 
> for (i=0;i<=PROFILES;i++) {
>     if (pkt.ip_addr == source_ip[i])
>         do_something(pkt,i)
> }
> 
> I will process at about millions entries per second and ~100 profiles. What
> do you think? It will work fine? fast? any suggest?
> 
> thanks
> Victor

Hi Victor,

I would consider using a simple hash table. Use ipaddr as a key to
do fast lookup of the value. Take a look at scripts/fixdep.c which
includes a FNV hash table implementation.


From victordetoni at gmail.com  Wed Feb 10 17:49:30 2016
From: victordetoni at gmail.com (Victor Detoni)
Date: Wed, 10 Feb 2016 20:49:30 -0200
Subject: Question about memory in C
In-Reply-To: <20160210212553.GA8415@portege>
References: <CANpwN=u71yvBSc8B7y5D3zVs1=AYNo_jbOMPQPEkHsmqx9HEHw@mail.gmail.com>
	<20160210212553.GA8415@portege>
Message-ID: <CANpwN=v=MB=RSpQiNaOsJ8iAX2KLETF98otLM1FAnwJGY+JHow@mail.gmail.com>

Hi,

Thank you for your tip! I really appreciate it. In my situation I will have
many profiles and for each profile I can have many ip address, for example:

profile 1:
192.168.0.0/24
192.168.1.2/32
192.168.14/23
...

profile 2:
10.10.10.0/24
10.11.12.0/23
...

What's your opinion? I'm thinking to use pcap library, but I still haven't
the key.

On Wed, Feb 10, 2016 at 7:25 PM, Cihangir Akturk <cakturk at gmail.com> wrote:

> On Wed, Feb 10, 2016 at 11:40:44AM -0200, Victor Detoni wrote:
> > Hi all,
> >
> > I'm working for a network security prototype and I would like to know the
> > best way to read diferent configs from the memory, for example:
> >
> > My program will receive many pkts from network interface and it needs to
> > know what's profile it will use based on source ip address.
> >
> > First all, I'm thinking to use array in C, for example:
> >
> > for (i=0;i<=PROFILES;i++) {
> >     if (pkt.ip_addr == source_ip[i])
> >         do_something(pkt,i)
> > }
> >
> > I will process at about millions entries per second and ~100 profiles.
> What
> > do you think? It will work fine? fast? any suggest?
> >
> > thanks
> > Victor
>
> Hi Victor,
>
> I would consider using a simple hash table. Use ipaddr as a key to
> do fast lookup of the value. Take a look at scripts/fixdep.c which
> includes a FNV hash table implementation.
>
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From greg at kroah.com  Wed Feb 10 18:19:38 2016
From: greg at kroah.com (Greg KH)
Date: Wed, 10 Feb 2016 15:19:38 -0800
Subject: Question about memory in C
In-Reply-To: <CANpwN=v=MB=RSpQiNaOsJ8iAX2KLETF98otLM1FAnwJGY+JHow@mail.gmail.com>
References: <CANpwN=u71yvBSc8B7y5D3zVs1=AYNo_jbOMPQPEkHsmqx9HEHw@mail.gmail.com>
	<20160210212553.GA8415@portege>
	<CANpwN=v=MB=RSpQiNaOsJ8iAX2KLETF98otLM1FAnwJGY+JHow@mail.gmail.com>
Message-ID: <20160210231938.GA22076@kroah.com>

On Wed, Feb 10, 2016 at 08:49:30PM -0200, Victor Detoni wrote:
> Hi,
> 
> Thank you for your tip! I really appreciate it. In my situation I will have
> many profiles and for each profile I can have many ip address, for example:
> 
> profile 1:
> 192.168.0.0/24
> 192.168.1.2/32
> 192.168.14/23
> ...
> 
> profile 2:
> 10.10.10.0/24
> 10.11.12.0/23
> ...
> 
> What's your opinion? I'm thinking to use pcap library, but I still haven't the
> key.

I think you have a long way to go before you need to worry about stuff
like this.  Why not test and see exactly _where_ the performance
problems are before trying to solve things you don't know are actually
problems yet.

good luck,

greg k-h


From ricardo.ribalda at gmail.com  Thu Feb 11 08:56:32 2016
From: ricardo.ribalda at gmail.com (Ricardo Ribalda Delgado)
Date: Thu, 11 Feb 2016 14:56:32 +0100
Subject: Backtrace of every the threads
In-Reply-To: <55546.1455111426@turing-police.cc.vt.edu>
References: <CAPybu_0+Qj2CwQ0NeryDmqRZyFcA8JrSTfAOfTdfXsg5X2A-Ew@mail.gmail.com>
	<87k2mcx6pb.fsf@fatcat.parallelwireless>
	<CAPybu_0n87MkSQrydgzt7+ket7OgEn3FWuFmAnbuM3=Ac45J0Q@mail.gmail.com>
	<87io1wx3d4.fsf@fatcat.parallelwireless>
	<CAPybu_0xo1jF0UQnHcHfF0w=KBdUJB5U2D0=bEnaQhSUjhuDiQ@mail.gmail.com>
	<55546.1455111426@turing-police.cc.vt.edu>
Message-ID: <CAPybu_3Q3frmmwL4Fb=d8SBigsc4cC6KVrAoa4kTEzEJsky-ig@mail.gmail.com>

Hi Valdis

On Wed, Feb 10, 2016 at 2:37 PM,  <Valdis.Kletnieks at vt.edu> wrote:
>
> See what happens when you do 'echo t > /proc/sysrq-trigger'.

This is exactly what I was needing :) I owe you a beer.

>
> Note that you probably *don't* actually want a trace of *all* tasks (hint -
> what happens on a large system that has 2,000 cores on it)?

This is a embedded system with "only" 70 process.

I agree that on another system this is not the way to debug it.


>
> What problem are you trying to solve by getting a trace of everything? (Hint -
> what meaning does a userspace stack traceback have if you're looking at
> the corresponding kernel stack trace?)

I was doing:

cat /dev/video0

And the open()  syscall sometimes was stalling.

I wanted to know at what place open() syscall was waiting...

The error was due to a wrong locking methodology (in my code)


Thanks again!




-- 
Ricardo Ribalda


From Valdis.Kletnieks at vt.edu  Thu Feb 11 13:05:32 2016
From: Valdis.Kletnieks at vt.edu (Valdis.Kletnieks at vt.edu)
Date: Thu, 11 Feb 2016 13:05:32 -0500
Subject: Backtrace of every the threads
In-Reply-To: <CAPybu_3Q3frmmwL4Fb=d8SBigsc4cC6KVrAoa4kTEzEJsky-ig@mail.gmail.com>
References: <CAPybu_0+Qj2CwQ0NeryDmqRZyFcA8JrSTfAOfTdfXsg5X2A-Ew@mail.gmail.com>
	<87k2mcx6pb.fsf@fatcat.parallelwireless>
	<CAPybu_0n87MkSQrydgzt7+ket7OgEn3FWuFmAnbuM3=Ac45J0Q@mail.gmail.com>
	<87io1wx3d4.fsf@fatcat.parallelwireless>
	<CAPybu_0xo1jF0UQnHcHfF0w=KBdUJB5U2D0=bEnaQhSUjhuDiQ@mail.gmail.com>
	<55546.1455111426@turing-police.cc.vt.edu>
	<CAPybu_3Q3frmmwL4Fb=d8SBigsc4cC6KVrAoa4kTEzEJsky-ig@mail.gmail.com>
Message-ID: <90602.1455213932@turing-police.cc.vt.edu>

On Thu, 11 Feb 2016 14:56:32 +0100, Ricardo Ribalda Delgado said:

> > What problem are you trying to solve by getting a trace of everything? (Hint -
> > what meaning does a userspace stack traceback have if you're looking at
> > the corresponding kernel stack trace?)
>
> I was doing:
>
> cat /dev/video0
>
> And the open()  syscall sometimes was stalling.
>
> I wanted to know at what place open() syscall was waiting...

You can find *that* out by doing  a 'cat /proc/NNNN/stack' for NNNN == process id.

No need to find *all* the stack traces for that. :)
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From varyani.nitin1 at gmail.com  Sat Feb 13 01:12:57 2016
From: varyani.nitin1 at gmail.com (Nitin Varyani)
Date: Sat, 13 Feb 2016 11:42:57 +0530
Subject: Process scheduling
Message-ID: <CAKfJ7KKcBRg1nKQwfAwL0N_bfb-GAa39sVLfFu=ykea1t3yv_A@mail.gmail.com>

Hello,
         I want to understand the flow of code of process scheduler of
linux kernel. What I have understood is that
The task marks itself as sleeping,
puts itself on a wait queue,
removes itself from the red-black tree of runnable, and
calls schedule() to select a new process to execute.

for Waking back up
The task is set as runnable,
removed from the wait queue,
and added back to the red-black tree.

Can I get the details of which function does what? in sched/core.c and in
sched/fair.c
I am concerned only with fair scheduler. There are so many functions in
these two files that I am totally confused.
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From henrik at austad.us  Sat Feb 13 03:49:04 2016
From: henrik at austad.us (Henrik Austad)
Date: Sat, 13 Feb 2016 09:49:04 +0100
Subject: Process scheduling
In-Reply-To: <CAKfJ7KKcBRg1nKQwfAwL0N_bfb-GAa39sVLfFu=ykea1t3yv_A@mail.gmail.com>
References: <CAKfJ7KKcBRg1nKQwfAwL0N_bfb-GAa39sVLfFu=ykea1t3yv_A@mail.gmail.com>
Message-ID: <20160213084904.GB21526@icarus.home.austad.us>

On Sat, Feb 13, 2016 at 11:42:57AM +0530, Nitin Varyani wrote:
> Hello,

Hi Nitin,

>          I want to understand the flow of code of process scheduler of
> linux kernel. What I have understood is that
> The task marks itself as sleeping,
> puts itself on a wait queue,
> removes itself from the red-black tree of runnable, and
> calls schedule() to select a new process to execute.
> 
> for Waking back up
> The task is set as runnable,
> removed from the wait queue,
> and added back to the red-black tree.
> 
> Can I get the details of which function does what? in sched/core.c and in
> sched/fair.c
> I am concerned only with fair scheduler. There are so many functions in
> these two files that I am totally confused.

Then core.c and fair.c is the best bet.

You could also pick up a copy of Linux kernel development (By Love), it 
gives a nice introduction to the overall flow of .. well mostly everything. 
:)

In kernel/sched/sched.h you have a struct called 'struct sched_class" which 
is a set of function-points. This is used by the core machinery to call 
into scheduling-class specific code. At the bottom of fair.c, you see said 
struct being populated.

Also, if you want to see what really happens, try enabling 
function-tracing, but limit it to sched-functions only (and sched-events, 
those are also useful to see what triggers things)

mount -t debugfs nodev /sys/kernel/debug
cd /sys/kernel/debug/tracing
echo 0 > tracing_on	
echo function > current_tracer
echo "sched*" > set_ftrace_filter
echo 1 > events/sched/enable
echo 1 > tracing_on
... wait for a few secs
echo 0 > tracing_on

cat trace > /tmp/trace.txt

Now, look at trace.txt and correlate it to the scheduler code :)

Good luck!

-- 
Henrik Austad
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From varyani.nitin1 at gmail.com  Sat Feb 13 04:42:35 2016
From: varyani.nitin1 at gmail.com (Nitin Varyani)
Date: Sat, 13 Feb 2016 15:12:35 +0530
Subject: Process scheduling
In-Reply-To: <20160213084904.GB21526@icarus.home.austad.us>
References: <CAKfJ7KKcBRg1nKQwfAwL0N_bfb-GAa39sVLfFu=ykea1t3yv_A@mail.gmail.com>
	<20160213084904.GB21526@icarus.home.austad.us>
Message-ID: <CAKfJ7KLkSER2fka7tpYhgGg61FxG-NOO5WjutG0nSCSt4MVheA@mail.gmail.com>

thanks

On Sat, Feb 13, 2016 at 2:19 PM, Henrik Austad <henrik at austad.us> wrote:

> On Sat, Feb 13, 2016 at 11:42:57AM +0530, Nitin Varyani wrote:
> > Hello,
>
> Hi Nitin,
>
> >          I want to understand the flow of code of process scheduler of
> > linux kernel. What I have understood is that
> > The task marks itself as sleeping,
> > puts itself on a wait queue,
> > removes itself from the red-black tree of runnable, and
> > calls schedule() to select a new process to execute.
> >
> > for Waking back up
> > The task is set as runnable,
> > removed from the wait queue,
> > and added back to the red-black tree.
> >
> > Can I get the details of which function does what? in sched/core.c and in
> > sched/fair.c
> > I am concerned only with fair scheduler. There are so many functions in
> > these two files that I am totally confused.
>
> Then core.c and fair.c is the best bet.
>
> You could also pick up a copy of Linux kernel development (By Love), it
> gives a nice introduction to the overall flow of .. well mostly everything.
> :)
>
> In kernel/sched/sched.h you have a struct called 'struct sched_class" which
> is a set of function-points. This is used by the core machinery to call
> into scheduling-class specific code. At the bottom of fair.c, you see said
> struct being populated.
>
> Also, if you want to see what really happens, try enabling
> function-tracing, but limit it to sched-functions only (and sched-events,
> those are also useful to see what triggers things)
>
> mount -t debugfs nodev /sys/kernel/debug
> cd /sys/kernel/debug/tracing
> echo 0 > tracing_on
> echo function > current_tracer
> echo "sched*" > set_ftrace_filter
> echo 1 > events/sched/enable
> echo 1 > tracing_on
> ... wait for a few secs
> echo 0 > tracing_on
>
> cat trace > /tmp/trace.txt
>
> Now, look at trace.txt and correlate it to the scheduler code :)
>
> Good luck!
>
> --
> Henrik Austad
>
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From tobaccopipeyoyo at gmail.com  Sat Feb 13 21:16:50 2016
From: tobaccopipeyoyo at gmail.com (tobaccopipeyoyo .)
Date: Sat, 13 Feb 2016 18:16:50 -0800
Subject: current during interrupt servicing
Message-ID: <CAAQJGeuCdGF_wucvXgC6Ps=Xnysjje6xuaGSOWB3CWOQdiJU7w@mail.gmail.com>

Hi,
I'm new to kernel programming, currently started ldd book
For the current process it says that global item current returns the
task_struct of the currently running process.

What if I refer this global during interrupt servicing?
What will happen? What should I expect.

Thanks,
tpyy


From pratyushpatel.1995 at gmail.com  Sun Feb 14 00:30:40 2016
From: pratyushpatel.1995 at gmail.com (Pratyush Patel)
Date: Sun, 14 Feb 2016 11:00:40 +0530
Subject: Locking while executing bottom-halves and process context code
Message-ID: <CAAnMKKb9VafTzfZn3LNUDC4XbeT054ueEVx_-AkgNbgS9aGufw@mail.gmail.com>

Hello,

While reading a section in Linux Kernel Development, I came across the
following:

"If process context code and a bottom half share data, you need to
disable bottom-half processing and obtain a lock before accessing the
data."

Why is this the case? Can one not disable/lock the process context
code instead of the bottom-half and access data?

Similarly, for the statement,

"If interrupt context code and a bottom half share data, you need to
disable interrupts and obtain a lock before accessing the data."

Any help in clarifying this would be much appreciated.

Thanks,
Pratyush


From henrik at austad.us  Sun Feb 14 05:10:14 2016
From: henrik at austad.us (Henrik Austad)
Date: Sun, 14 Feb 2016 11:10:14 +0100
Subject: Locking while executing bottom-halves and process context code
In-Reply-To: <CAAnMKKb9VafTzfZn3LNUDC4XbeT054ueEVx_-AkgNbgS9aGufw@mail.gmail.com>
References: <CAAnMKKb9VafTzfZn3LNUDC4XbeT054ueEVx_-AkgNbgS9aGufw@mail.gmail.com>
Message-ID: <20160214101014.GC21526@icarus.home.austad.us>

On Sun, Feb 14, 2016 at 11:00:40AM +0530, Pratyush Patel wrote:
> Hello,
> 
> While reading a section in Linux Kernel Development, I came across the
> following:
> 
> "If process context code and a bottom half share data, you need to
> disable bottom-half processing and obtain a lock before accessing the
> data."
> 
> Why is this the case? Can one not disable/lock the process context
> code instead of the bottom-half and access data?

You need to do it in both.

You need to grab the lock in BH in case other threads also calls the same 
syscall. You need to lock in from user process context to avoid being 
interrupted and having a BH walk in and update the data.

 A Thread
   |
   do_something()
      do_a_syscall()
         // update a var in kernel, but on behalf of thread
	 read shared var A
 * Interrupt *
   irq_entry
     // ack interrupt, do critical stuff
     // trigger softirq do the rest
   irq_exit
   softirq_entry
     Update shared var A
   softirq_exit

   (now back in thread A, inside kernel)
          write old value of A back // updated A from softirq now lost!


> Similarly, for the statement,
> 
> "If interrupt context code and a bottom half share data, you need to
> disable interrupts and obtain a lock before accessing the data."
> 
> Any help in clarifying this would be much appreciated.

Same as for userprocess vs. BH, an ISR can interrupt a BH and update data 
unless you have disabled interrupt. 

HTH,

-- 
Henrik Austad
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From pratyushpatel.1995 at gmail.com  Sun Feb 14 05:28:20 2016
From: pratyushpatel.1995 at gmail.com (Pratyush Patel)
Date: Sun, 14 Feb 2016 15:58:20 +0530
Subject: Locking while executing bottom-halves and process context code
In-Reply-To: <20160214101014.GC21526@icarus.home.austad.us>
References: <CAAnMKKb9VafTzfZn3LNUDC4XbeT054ueEVx_-AkgNbgS9aGufw@mail.gmail.com>
	<20160214101014.GC21526@icarus.home.austad.us>
Message-ID: <CAAnMKKYFjBc4E9wJadmNda9=sfHE=gd4hkoFc9qcK0iO6Ti6+Q@mail.gmail.com>

On Sun, Feb 14, 2016 at 3:40 PM, Henrik Austad <henrik at austad.us> wrote:
> On Sun, Feb 14, 2016 at 11:00:40AM +0530, Pratyush Patel wrote:
>> Hello,
>>
>> While reading a section in Linux Kernel Development, I came across the
>> following:
>>
>> "If process context code and a bottom half share data, you need to
>> disable bottom-half processing and obtain a lock before accessing the
>> data."
>>
>> Why is this the case? Can one not disable/lock the process context
>> code instead of the bottom-half and access data?
>
> You need to do it in both.

That makes a lot more sense.


> You need to grab the lock in BH in case other threads also calls the same
> syscall. You need to lock in from user process context to avoid being
> interrupted and having a BH walk in and update the data.
>
>  A Thread
>    |
>    do_something()
>       do_a_syscall()
>          // update a var in kernel, but on behalf of thread
>          read shared var A
>  * Interrupt *
>    irq_entry
>      // ack interrupt, do critical stuff
>      // trigger softirq do the rest
>    irq_exit
>    softirq_entry
>      Update shared var A
>    softirq_exit
>
>    (now back in thread A, inside kernel)
>           write old value of A back // updated A from softirq now lost!
>

Wonderful explanation, thank you.


>
>> Similarly, for the statement,
>>
>> "If interrupt context code and a bottom half share data, you need to
>> disable interrupts and obtain a lock before accessing the data."
>>
>> Any help in clarifying this would be much appreciated.
>
> Same as for userprocess vs. BH, an ISR can interrupt a BH and update data
> unless you have disabled interrupt.


-Pratyush


From mulyadi.santosa at gmail.com  Sun Feb 14 13:10:53 2016
From: mulyadi.santosa at gmail.com (Mulyadi Santosa)
Date: Mon, 15 Feb 2016 01:10:53 +0700
Subject: current during interrupt servicing
In-Reply-To: <CAAQJGeuCdGF_wucvXgC6Ps=Xnysjje6xuaGSOWB3CWOQdiJU7w@mail.gmail.com>
References: <CAAQJGeuCdGF_wucvXgC6Ps=Xnysjje6xuaGSOWB3CWOQdiJU7w@mail.gmail.com>
Message-ID: <CAGdaadYgnA7JwfgUCxa=hiJjQm4Oz+rDy-htZCi6cdw7O8WFgg@mail.gmail.com>

On Sun, Feb 14, 2016 at 9:16 AM, tobaccopipeyoyo . <
tobaccopipeyoyo at gmail.com> wrote:

> Hi,
> I'm new to kernel programming, currently started ldd book
> For the current process it says that global item current returns the
> task_struct of the currently running process.
>
> What if I refer this global during interrupt servicing?
> What will happen? What should I expect.
>
> Thanks,
> tpyy
>
>
Hi...

during interrupt servicing, "current" will give you last process' data
structure that's get interrupted by the interrupt. Of course, this is per
cpu context, so if you are in SMP situation, current will return task
struct in that CPU only.

The essential thing in interrupt servicing is: interrupt handler runs on
behalf of current running process.

Hopefully I still recall all these correctly.


-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com
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From yuzibode at 126.com  Sun Feb 14 18:46:36 2016
From: yuzibode at 126.com (YU Bo)
Date: Mon, 15 Feb 2016 07:46:36 +0800 (CST)
Subject: Merge conflict
Message-ID: <50a639e9.361.152e22dc5ea.Coremail.yuzibode@126.com>

Hi,
Some days ago i followed the tips:
http://kernelnewbies.org/FirstKernelPatch
git clone greg's git tree and built branch first-patch.
Due to my first patch that fixes coding style reported
by checkptch.pl didn't applied,so i intend to rebase my 
git branch first-patch.The question i encounter is:
==================git command && output========
yubo at debian:~/maintree/staging$  git rebase first-patch
It looks like git-am is in progress. Cannot rebase.
yubo at debian:~/maintree/staging$ git am --abort 
You seem to have moved HEAD since the last 'am' failure.
Not rewinding to ORIG_HEAD
yubo at debian:~/maintree/staging$ git rebase first-patch
First, rewinding head to replay your work on top of it...
Applying: ovl: default permissions
Using index info to reconstruct a base tree...
Falling back to patching base and 3-way merge...
----
Auto-merging drivers/gpu/drm/i915/intel_display.c
CONFLICT (content): Merge conflict in drivers/gpu/drm/i915/intel_display.c
Failed to merge in the changes.
Patch failed at 0010 drm/i915: Only run commit when crtc is active, v2.


Is there  something with wrong?
Thanks in advance for the noisy.
--
Best Regards
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From newell.roger at gmail.com  Sun Feb 14 18:51:40 2016
From: newell.roger at gmail.com (Roger H Newell)
Date: Sun, 14 Feb 2016 20:21:40 -0330
Subject: Merge conflict
In-Reply-To: <50a639e9.361.152e22dc5ea.Coremail.yuzibode@126.com>
References: <50a639e9.361.152e22dc5ea.Coremail.yuzibode@126.com>
Message-ID: <CAEE9rjYv7AxAeMZkVCphwW61QNi3VDyETMw+F87PdTRkAP6N6w@mail.gmail.com>

I think you want to have first-patch checked out and rebase
origin/staging-testing ? You mite also consider checking out
staging-testing first and run git fetch origin.

On Feb 14, 2016 8:17 PM, "YU Bo" <yuzibode at 126.com> wrote:
>
> Hi,
> Some days ago i followed the tips:
> http://kernelnewbies.org/FirstKernelPatch
> git clone greg's git tree and built branch first-patch.
> Due to my first patch that fixes coding style reported
> by checkptch.pl didn't applied,so i intend to rebase my
> git branch first-patch.The question i encounter is:
> ==================git command && output========
> yubo at debian:~/maintree/staging$  git rebase first-patch
> It looks like git-am is in progress. Cannot rebase.
> yubo at debian:~/maintree/staging$ git am --abort
> You seem to have moved HEAD since the last 'am' failure.
> Not rewinding to ORIG_HEAD
> yubo at debian:~/maintree/staging$ git rebase first-patch
> First, rewinding head to replay your work on top of it...
> Applying: ovl: default permissions
> Using index info to reconstruct a base tree...
> Falling back to patching base and 3-way merge...
> ----
> Auto-merging drivers/gpu/drm/i915/intel_display.c
> CONFLICT (content): Merge conflict in drivers/gpu/drm/i915/intel_display.c
> Failed to merge in the changes.
> Patch failed at 0010 drm/i915: Only run commit when crtc is active, v2.
>
> Is there  something with wrong?
> Thanks in advance for the noisy.
> --
> Best Regards
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
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From yuzibode at 126.com  Sun Feb 14 19:10:35 2016
From: yuzibode at 126.com (YU Bo)
Date: Mon, 15 Feb 2016 08:10:35 +0800 (CST)
Subject: Merge conflict
In-Reply-To: <CAEE9rjYv7AxAeMZkVCphwW61QNi3VDyETMw+F87PdTRkAP6N6w@mail.gmail.com>
References: <50a639e9.361.152e22dc5ea.Coremail.yuzibode@126.com>
	<CAEE9rjYv7AxAeMZkVCphwW61QNi3VDyETMw+F87PdTRkAP6N6w@mail.gmail.com>
Message-ID: <35d0bb5e.45d.152e243ba6a.Coremail.yuzibode@126.com>

Hi,
I just have checkouted origin/staging-testing and git rebase first-patch.Now,
=============git command && output==============
yubo at debian:~/maintree/staging$ git branch -a
* (no branch)
  first-patch
  staging-next
  staging-testing
  remotes/origin/HEAD -> origin/master
  remotes/origin/master
  remotes/origin/staging-linus
  remotes/origin/staging-next
  remotes/origin/staging-testing
  remotes/origin/test
ubo at debian:~/maintree/staging$ git fetch origin
remote: Counting objects: 273, done.
remote: Compressing objects: 100% (273/273), done.
remote: Total 273 (delta 160), reused 0 (delta 0)
Receiving objects: 100% (273/273), 298.64 KiB | 196 KiB/s, done.
Resolving deltas: 100% (160/160), done.
From git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
   2cdb82c..d9750a2  staging-next -> origin/staging-next
yubo at debian:~/maintree/staging$ git checkout staging-testing 
drivers/gpu/drm/i915/intel_display.c: needs merge
error: you need to resolve your current index first
===============end==================









--
Best Regards


? 2016-02-15 07:51:40?"Roger H Newell" <newell.roger at gmail.com> ???


I think you want to have first-patch checked out and rebase origin/staging-testing ? You mite also consider checking out staging-testing first and run git fetch origin.

On Feb 14, 2016 8:17 PM, "YU Bo" <yuzibode at 126.com> wrote:
>
> Hi,
> Some days ago i followed the tips:
> http://kernelnewbies.org/FirstKernelPatch
> git clone greg's git tree and built branch first-patch.
> Due to my first patch that fixes coding style reported
> by checkptch.pl didn't applied,so i intend to rebase my 
> git branch first-patch.The question i encounter is:
> ==================git command && output========
> yubo at debian:~/maintree/staging$  git rebase first-patch
> It looks like git-am is in progress. Cannot rebase.
> yubo at debian:~/maintree/staging$ git am --abort 
> You seem to have moved HEAD since the last 'am' failure.
> Not rewinding to ORIG_HEAD
> yubo at debian:~/maintree/staging$ git rebase first-patch
> First, rewinding head to replay your work on top of it...
> Applying: ovl: default permissions
> Using index info to reconstruct a base tree...
> Falling back to patching base and 3-way merge...
> ----
> Auto-merging drivers/gpu/drm/i915/intel_display.c
> CONFLICT (content): Merge conflict in drivers/gpu/drm/i915/intel_display.c
> Failed to merge in the changes.
> Patch failed at 0010 drm/i915: Only run commit when crtc is active, v2.
>
> Is there  something with wrong?
> Thanks in advance for the noisy.
> --
> Best Regards
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
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From yuzibode at 126.com  Sun Feb 14 19:15:41 2016
From: yuzibode at 126.com (YU Bo)
Date: Mon, 15 Feb 2016 08:15:41 +0800 (CST)
Subject: Merge conflict
In-Reply-To: <35d0bb5e.45d.152e243ba6a.Coremail.yuzibode@126.com>
References: <50a639e9.361.152e22dc5ea.Coremail.yuzibode@126.com>
	<CAEE9rjYv7AxAeMZkVCphwW61QNi3VDyETMw+F87PdTRkAP6N6w@mail.gmail.com>
	<35d0bb5e.45d.152e243ba6a.Coremail.yuzibode@126.com>
Message-ID: <57bd53d7.4b9.152e248655d.Coremail.yuzibode@126.com>

Sorry for hasty to send previous email.
Maybe i have to delete the branch first-patch.But 
i still will figure out the problem in git way.
Thank you,
--
Best Regards


? 2016-02-15 08:10:35?"YU Bo" <yuzibode at 126.com> ???

Hi,
I just have checkouted origin/staging-testing and git rebase first-patch.Now,
=============git command && output==============
yubo at debian:~/maintree/staging$ git branch -a
* (no branch)
  first-patch
  staging-next
  staging-testing
  remotes/origin/HEAD -> origin/master
  remotes/origin/master
  remotes/origin/staging-linus
  remotes/origin/staging-next
  remotes/origin/staging-testing
  remotes/origin/test
ubo at debian:~/maintree/staging$ git fetch origin
remote: Counting objects: 273, done.
remote: Compressing objects: 100% (273/273), done.
remote: Total 273 (delta 160), reused 0 (delta 0)
Receiving objects: 100% (273/273), 298.64 KiB | 196 KiB/s, done.
Resolving deltas: 100% (160/160), done.
From git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
   2cdb82c..d9750a2  staging-next -> origin/staging-next
yubo at debian:~/maintree/staging$ git checkout staging-testing 
drivers/gpu/drm/i915/intel_display.c: needs merge
error: you need to resolve your current index first
===============end==================









--
Best Regards


? 2016-02-15 07:51:40?"Roger H Newell" <newell.roger at gmail.com> ???


I think you want to have first-patch checked out and rebase origin/staging-testing ? You mite also consider checking out staging-testing first and run git fetch origin.

On Feb 14, 2016 8:17 PM, "YU Bo" <yuzibode at 126.com> wrote:
>
> Hi,
> Some days ago i followed the tips:
> http://kernelnewbies.org/FirstKernelPatch
> git clone greg's git tree and built branch first-patch.
> Due to my first patch that fixes coding style reported
> by checkptch.pl didn't applied,so i intend to rebase my 
> git branch first-patch.The question i encounter is:
> ==================git command && output========
> yubo at debian:~/maintree/staging$  git rebase first-patch
> It looks like git-am is in progress. Cannot rebase.
> yubo at debian:~/maintree/staging$ git am --abort 
> You seem to have moved HEAD since the last 'am' failure.
> Not rewinding to ORIG_HEAD
> yubo at debian:~/maintree/staging$ git rebase first-patch
> First, rewinding head to replay your work on top of it...
> Applying: ovl: default permissions
> Using index info to reconstruct a base tree...
> Falling back to patching base and 3-way merge...
> ----
> Auto-merging drivers/gpu/drm/i915/intel_display.c
> CONFLICT (content): Merge conflict in drivers/gpu/drm/i915/intel_display.c
> Failed to merge in the changes.
> Patch failed at 0010 drm/i915: Only run commit when crtc is active, v2.
>
> Is there  something with wrong?
> Thanks in advance for the noisy.
> --
> Best Regards
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
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From vishu.kernel at gmail.com  Sun Feb 14 22:47:32 2016
From: vishu.kernel at gmail.com (Vishwas Srivastava)
Date: Mon, 15 Feb 2016 09:17:32 +0530
Subject: Kernelnewbies Digest, Vol 63, Issue 20
Message-ID: <CAGM3cC7K-N0jeYNjxaKdbZ1_cCcKKUiMWzySpmpLwp1gL37OaQ@mail.gmail.com>

---------- Forwarded message ----------
From: <kernelnewbies-request at kernelnewbies.org>
Date: Mon, Feb 15, 2016 at 5:40 AM
Subject: Kernelnewbies Digest, Vol 63, Issue 20
To: kernelnewbies at kernelnewbies.org


Send Kernelnewbies mailing list submissions to
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When replying, please edit your Subject line so it is more specific
than "Re: Contents of Kernelnewbies digest..."


Today's Topics:

   1. Re: current during interrupt servicing (Mulyadi Santosa)
   2. Merge conflict (YU Bo)
   3. Re: Merge conflict (Roger H Newell)
   4. Re:Re: Merge conflict (YU Bo)


----------------------------------------------------------------------

Message: 1
Date: Mon, 15 Feb 2016 01:10:53 +0700
From: Mulyadi Santosa <mulyadi.santosa at gmail.com>
Subject: Re: current during interrupt servicing
To: "tobaccopipeyoyo ." <tobaccopipeyoyo at gmail.com>
Cc: kernelnewbies <kernelnewbies at kernelnewbies.org>
Message-ID:
        <CAGdaadYgnA7JwfgUCxa=hiJjQm4Oz+rDy-htZCi6cdw7O8WFgg at mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

On Sun, Feb 14, 2016 at 9:16 AM, tobaccopipeyoyo . <
tobaccopipeyoyo at gmail.com> wrote:

> Hi,
> I'm new to kernel programming, currently started ldd book
> For the current process it says that global item current returns the
> task_struct of the currently running process.
>
> What if I refer this global during interrupt servicing?
> What will happen? What should I expect.
>
> Thanks,
> tpyy
>
>
Hi...

during interrupt servicing, "current" will give you last process' data
structure that's get interrupted by the interrupt. Of course, this is per
cpu context, so if you are in SMP situation, current will return task
struct in that CPU only.

The essential thing in interrupt servicing is: interrupt handler runs on
behalf of current running process.

Hopefully I still recall all these correctly.


--
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

Hi Mulyadi,
                    I disagree with the statement you made here that
"interrupt handler runs on behalf of current running process".
Your statement is valid for system calls (software interrupt) but not for
the real "interrupt"
Interrupt handler are nowhere related to any process. They run their own
without caring about
which process was running.
--- Vishwas

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com
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Message: 2
Date: Mon, 15 Feb 2016 07:46:36 +0800 (CST)
From: "YU Bo" <yuzibode at 126.com>
Subject: Merge conflict
To: "kernelnewbies at kernelnewbies.org"
        <kernelnewbies at kernelnewbies.org>
Message-ID: <50a639e9.361.152e22dc5ea.Coremail.yuzibode at 126.com>
Content-Type: text/plain; charset="gbk"

Hi,
Some days ago i followed the tips:
http://kernelnewbies.org/FirstKernelPatch
git clone greg's git tree and built branch first-patch.
Due to my first patch that fixes coding style reported
by checkptch.pl didn't applied,so i intend to rebase my
git branch first-patch.The question i encounter is:
==================git command && output========
yubo at debian:~/maintree/staging$  git rebase first-patch
It looks like git-am is in progress. Cannot rebase.
yubo at debian:~/maintree/staging$ git am --abort
You seem to have moved HEAD since the last 'am' failure.
Not rewinding to ORIG_HEAD
yubo at debian:~/maintree/staging$ git rebase first-patch
First, rewinding head to replay your work on top of it...
Applying: ovl: default permissions
Using index info to reconstruct a base tree...
Falling back to patching base and 3-way merge...
----
Auto-merging drivers/gpu/drm/i915/intel_display.c
CONFLICT (content): Merge conflict in drivers/gpu/drm/i915/intel_display.c
Failed to merge in the changes.
Patch failed at 0010 drm/i915: Only run commit when crtc is active, v2.


Is there  something with wrong?
Thanks in advance for the noisy.
--
Best Regards
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------------------------------

Message: 3
Date: Sun, 14 Feb 2016 20:21:40 -0330
From: Roger H Newell <newell.roger at gmail.com>
Subject: Re: Merge conflict
To: YU Bo <yuzibode at 126.com>
Cc: kernelnewbies at kernelnewbies.org
Message-ID:
        <CAEE9rjYv7AxAeMZkVCphwW61QNi3VDyETMw+F87PdTRkAP6N6w at mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

I think you want to have first-patch checked out and rebase
origin/staging-testing ? You mite also consider checking out
staging-testing first and run git fetch origin.

On Feb 14, 2016 8:17 PM, "YU Bo" <yuzibode at 126.com> wrote:
>
> Hi,
> Some days ago i followed the tips:
> http://kernelnewbies.org/FirstKernelPatch
> git clone greg's git tree and built branch first-patch.
> Due to my first patch that fixes coding style reported
> by checkptch.pl didn't applied,so i intend to rebase my
> git branch first-patch.The question i encounter is:
> ==================git command && output========
> yubo at debian:~/maintree/staging$  git rebase first-patch
> It looks like git-am is in progress. Cannot rebase.
> yubo at debian:~/maintree/staging$ git am --abort
> You seem to have moved HEAD since the last 'am' failure.
> Not rewinding to ORIG_HEAD
> yubo at debian:~/maintree/staging$ git rebase first-patch
> First, rewinding head to replay your work on top of it...
> Applying: ovl: default permissions
> Using index info to reconstruct a base tree...
> Falling back to patching base and 3-way merge...
> ----
> Auto-merging drivers/gpu/drm/i915/intel_display.c
> CONFLICT (content): Merge conflict in drivers/gpu/drm/i915/intel_display.c
> Failed to merge in the changes.
> Patch failed at 0010 drm/i915: Only run commit when crtc is active, v2.
>
> Is there  something with wrong?
> Thanks in advance for the noisy.
> --
> Best Regards
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
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------------------------------

Message: 4
Date: Mon, 15 Feb 2016 08:10:35 +0800 (CST)
From: "YU Bo" <yuzibode at 126.com>
Subject: Re:Re: Merge conflict
To: "Roger H Newell" <newell.roger at gmail.com>
Cc: kernelnewbies at kernelnewbies.org
Message-ID: <35d0bb5e.45d.152e243ba6a.Coremail.yuzibode at 126.com>
Content-Type: text/plain; charset="gbk"

Hi,
I just have checkouted origin/staging-testing and git rebase
first-patch.Now,
=============git command && output==============
yubo at debian:~/maintree/staging$ git branch -a
* (no branch)
  first-patch
  staging-next
  staging-testing
  remotes/origin/HEAD -> origin/master
  remotes/origin/master
  remotes/origin/staging-linus
  remotes/origin/staging-next
  remotes/origin/staging-testing
  remotes/origin/test
ubo at debian:~/maintree/staging$ git fetch origin
remote: Counting objects: 273, done.
remote: Compressing objects: 100% (273/273), done.
remote: Total 273 (delta 160), reused 0 (delta 0)
Receiving objects: 100% (273/273), 298.64 KiB | 196 KiB/s, done.
Resolving deltas: 100% (160/160), done.
>From git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
   2cdb82c..d9750a2  staging-next -> origin/staging-next
yubo at debian:~/maintree/staging$ git checkout staging-testing
drivers/gpu/drm/i915/intel_display.c: needs merge
error: you need to resolve your current index first
===============end==================









--
Best Regards


? 2016-02-15 07:51:40?"Roger H Newell" <newell.roger at gmail.com> ???


I think you want to have first-patch checked out and rebase
origin/staging-testing ? You mite also consider checking out
staging-testing first and run git fetch origin.

On Feb 14, 2016 8:17 PM, "YU Bo" <yuzibode at 126.com> wrote:
>
> Hi,
> Some days ago i followed the tips:
> http://kernelnewbies.org/FirstKernelPatch
> git clone greg's git tree and built branch first-patch.
> Due to my first patch that fixes coding style reported
> by checkptch.pl didn't applied,so i intend to rebase my
> git branch first-patch.The question i encounter is:
> ==================git command && output========
> yubo at debian:~/maintree/staging$  git rebase first-patch
> It looks like git-am is in progress. Cannot rebase.
> yubo at debian:~/maintree/staging$ git am --abort
> You seem to have moved HEAD since the last 'am' failure.
> Not rewinding to ORIG_HEAD
> yubo at debian:~/maintree/staging$ git rebase first-patch
> First, rewinding head to replay your work on top of it...
> Applying: ovl: default permissions
> Using index info to reconstruct a base tree...
> Falling back to patching base and 3-way merge...
> ----
> Auto-merging drivers/gpu/drm/i915/intel_display.c
> CONFLICT (content): Merge conflict in drivers/gpu/drm/i915/intel_display.c
> Failed to merge in the changes.
> Patch failed at 0010 drm/i915: Only run commit when crtc is active, v2.
>
> Is there  something with wrong?
> Thanks in advance for the noisy.
> --
> Best Regards
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
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------------------------------

_______________________________________________
Kernelnewbies mailing list
Kernelnewbies at kernelnewbies.org
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies


End of Kernelnewbies Digest, Vol 63, Issue 20
*********************************************
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From klshiva4a4 at gmail.com  Mon Feb 15 01:47:23 2016
From: klshiva4a4 at gmail.com (Shiva Shankar)
Date: Mon, 15 Feb 2016 12:17:23 +0530
Subject: counting semaphore question
Message-ID: <CAKe3+gJ9M=UqKCvVu6HWgAp2EKNpH-yQxd1PQtECwcCLidPH2Q@mail.gmail.com>

Hi all,
Can you anyone tell me what is the exact use of counting semaphore in
kernel ?

When should we use it ? what is the practical usage of counting semaphores
in
Linux kernel ?

I have seen only mutex (Binary semaphore)is used  for synchronization not
the counting semaphore(count >1).

Any sugguestions would be appreciated

Thanks in advance.
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From ckim at etri.re.kr  Mon Feb 15 03:56:37 2016
From: ckim at etri.re.kr (Chan Kim)
Date: Mon, 15 Feb 2016 08:56:37 +0000
Subject: counting semaphore question
In-Reply-To: <CAKe3+gJ9M=UqKCvVu6HWgAp2EKNpH-yQxd1PQtECwcCLidPH2Q@mail.gmail.com>
References: <CAKe3+gJ9M=UqKCvVu6HWgAp2EKNpH-yQxd1PQtECwcCLidPH2Q@mail.gmail.com>
Message-ID: <1A0A429E720CFD4A9673A435389F1636550B0E4C@SMTP4.etri.info>


Hi,
I'm not a proper person to reply to this question but at least I know what it is for.
see  below (from http://www.makelinux.net/books/lkd2/ch09lev1sec4)

Alternatively, the count can be initialized to a nonzero value greater than one. In this case, the semaphore is called a counting semaphore, and it allows at most count holders of the lock at a time. Counting semaphores are not used to enforce mutual exclusion because they allow multiple threads of execution in the critical region at once. Instead, they are used to enforce limits in certain code. They are not used much in the kernel. If you use a semaphore, you almost assuredly want to use a mutex (a semaphore with a count of one).

I don't know in what circumstances the number of resource holders should be limitted. Maybe for a subsystem handling synchronization itself but the number of users should be limited? Hope to hear from somebody with good examples.

regards,
Chan




?? ?? : "Shiva Shankar" <klshiva4a4 at gmail.com>
?? ?? : 2016-02-15 15:47:57 ( +09:00 )
?? ?? : kernelnewbies <kernelnewbies at kernelnewbies.org>
?? : 
?? : counting semaphore question


Hi all, 
Can you anyone tell me what is the exact use of counting semaphore in kernel ? 


When should we use it ? what is the practical usage of counting semaphores in 
Linux kernel ?

I have seen only mutex (Binary semaphore)is used  for synchronization not the counting semaphore(count >1).  

Any sugguestions would be appreciated 


Thanks in advance. 

From ebru.akagunduz at gmail.com  Mon Feb 15 03:57:46 2016
From: ebru.akagunduz at gmail.com (=?UTF-8?B?RWJydSBBa2Fnw7xuZMO8eg==?=)
Date: Mon, 15 Feb 2016 10:57:46 +0200
Subject: Merge conflict
In-Reply-To: <57bd53d7.4b9.152e248655d.Coremail.yuzibode@126.com>
References: <50a639e9.361.152e22dc5ea.Coremail.yuzibode@126.com>
	<CAEE9rjYv7AxAeMZkVCphwW61QNi3VDyETMw+F87PdTRkAP6N6w@mail.gmail.com>
	<35d0bb5e.45d.152e243ba6a.Coremail.yuzibode@126.com>
	<57bd53d7.4b9.152e248655d.Coremail.yuzibode@126.com>
Message-ID: <CADuXt-XGQkzhV7EUUx7TAB9hyFfKN+ir9Hs2Fr6iVM5eLD0Yxw@mail.gmail.com>

Hello,

>> Hi,
>> Some days ago i followed the tips:
>> http://kernelnewbies.org/FirstKernelPatch
>> git clone greg's git tree and built branch first-patch.
>> Due to my first patch that fixes coding style reported
>> by checkptch.pl didn't applied,so i intend to rebase my
>> git branch first-patch.The question i encounter is:
>> ==================git command && output========
>> yubo at debian:~/maintree/staging$  git rebase first-patch
>> It looks like git-am is in progress. Cannot rebase.
>> yubo at debian:~/maintree/staging$ git am --abort
>> You seem to have moved HEAD since the last 'am' failure.
>> Not rewinding to ORIG_HEAD
>> yubo at debian:~/maintree/staging$ git rebase first-patch
>> First, rewinding head to replay your work on top of it...
>> Applying: ovl: default permissions
>> Using index info to reconstruct a base tree...
>> Falling back to patching base and 3-way merge...
>> ----
>> Auto-merging drivers/gpu/drm/i915/intel_display.c
>> CONFLICT (content): Merge conflict in drivers/gpu/drm/i915/intel_display.c
>> Failed to merge in the changes.
>> Patch failed at 0010 drm/i915: Only run commit when crtc is active, v2.
>>
>> Is there  something with wrong?
>> Thanks in advance for the noisy.

If you would like to update your patch with newest version of the tree,
I recommend to you, use git am. Here is the blog post:
http://www.pizzhacks.com/bugdrome/2011/10/deal-with-git-am-failures/

After updating your current tree;

Firstly, you should give the command:
1- git am your_old_patch

After seeing, it could not be applied, give this:
2- git apply PATCH --reject

You'll see rejected and applied chunks, the rejected parts will be specified
with extension .rej (with related file name). You should edit related
files manually.

3- git add fixed_files
4- git am --resolved


All done :). This way seems easier to me. The blog post explained
steps, quite clear as well.

Kind regards,
Ebru

-- 
Ebru Akagunduz
http://www.ebruakagunduz.com


From mulyadi.santosa at gmail.com  Mon Feb 15 03:53:40 2016
From: mulyadi.santosa at gmail.com (Mulyadi Santosa)
Date: Mon, 15 Feb 2016 15:53:40 +0700
Subject: Kernelnewbies Digest, Vol 63, Issue 20
In-Reply-To: <CAGM3cC7K-N0jeYNjxaKdbZ1_cCcKKUiMWzySpmpLwp1gL37OaQ@mail.gmail.com>
References: <CAGM3cC7K-N0jeYNjxaKdbZ1_cCcKKUiMWzySpmpLwp1gL37OaQ@mail.gmail.com>
Message-ID: <CAGdaadYyV1050YJWWW-MzEiWNcbEjx1BTDJVKXsOYo9vP3tYeA@mail.gmail.com>

On Mon, Feb 15, 2016 at 10:47 AM, Vishwas Srivastava <vishu.kernel at gmail.com
> wrote:

>
> On Sun, Feb 14, 2016 at 9:16 AM, tobaccopipeyoyo . <
> tobaccopipeyoyo at gmail.com> wrote:
>
> > Hi,
> > I'm new to kernel programming, currently started ldd book
> > For the current process it says that global item current returns the
> > task_struct of the currently running process.
> >
> > What if I refer this global during interrupt servicing?
> > What will happen? What should I expect.
> >
> > Thanks,
> > tpyy
> >
> >
> Hi...
>
> during interrupt servicing, "current" will give you last process' data
> structure that's get interrupted by the interrupt. Of course, this is per
> cpu context, so if you are in SMP situation, current will return task
> struct in that CPU only.
>
> The essential thing in interrupt servicing is: interrupt handler runs on
> behalf of current running process.
>
> Hopefully I still recall all these correctly.
>
>
> --
> regards,
>
> Mulyadi Santosa
> Freelance Linux trainer and consultant
>
> Hi Mulyadi,
>                     I disagree with the statement you made here that
> "interrupt handler runs on behalf of current running process".
> Your statement is valid for system calls (software interrupt) but not for
> the real "interrupt"
> Interrupt handler are nowhere related to any process. They run their own
> without caring about
> which process was running.
> --- Vishwas
>
>
>
Hello Vishwas

Thank you for your correction.

You're correct. Maybe my wording is not exactly correct. My intention was
to point that especially during bottom half interrupt servicing, if you run
call "current", it will point to last process before kernel switch to
kernel mode servicing the interrupt. So the word "on behalf" is not exactly
correct, I admit that.

Feel free to correct if I am still wrong...



-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com
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From varyani.nitin1 at gmail.com  Mon Feb 15 07:37:22 2016
From: varyani.nitin1 at gmail.com (Nitin Varyani)
Date: Mon, 15 Feb 2016 18:07:22 +0530
Subject: Process scheduling
In-Reply-To: <CAKfJ7KLrDSLuw-8CQg4jvKdnPRvQqAXHE4Wf+sSZYqJYdzn3dg@mail.gmail.com>
References: <CAKfJ7KKcBRg1nKQwfAwL0N_bfb-GAa39sVLfFu=ykea1t3yv_A@mail.gmail.com>
	<20160213084904.GB21526@icarus.home.austad.us>
	<CAKfJ7KLkSER2fka7tpYhgGg61FxG-NOO5WjutG0nSCSt4MVheA@mail.gmail.com>
	<CAKfJ7KLrDSLuw-8CQg4jvKdnPRvQqAXHE4Wf+sSZYqJYdzn3dg@mail.gmail.com>
Message-ID: <CAKfJ7K+ZeZPPLBF9rUzDQgdz66+U_XNWmNgNnDf31B2oOSbj8g@mail.gmail.com>

On Mon, Feb 15, 2016 at 6:06 PM, Nitin Varyani <varyani.nitin1 at gmail.com>
wrote:

> Hi
>         I have studied LInux kernel CFS scheduling algorithm - the
> vruntime, weights, nice value, etc. I am able to understand the code.
>  Actually the task given to me is really very huge. I am told to design a
> distributed process scheduling algorithm. A very simple implementation of
> it will be sufficient for me. Current distributed OS are patch work over
> the linux kernels, that is, they are responsible for load balancing through
> process migration but the scheduling is taken care by the single machine
> linux kernels. My task is to make the scheduling algorithm itself as
> distributed. That is a scheduler makes a decision whether to migrate a task
> or to keep the task in the current system.  I need some design aspects of
> how to achieve it. Another thing which I want to know is that whether this
> job is possible for a kernel newbie like me.
>
> On Sat, Feb 13, 2016 at 3:12 PM, Nitin Varyani <varyani.nitin1 at gmail.com>
> wrote:
>
>> thanks
>>
>> On Sat, Feb 13, 2016 at 2:19 PM, Henrik Austad <henrik at austad.us> wrote:
>>
>>> On Sat, Feb 13, 2016 at 11:42:57AM +0530, Nitin Varyani wrote:
>>> > Hello,
>>>
>>> Hi Nitin,
>>>
>>> >          I want to understand the flow of code of process scheduler of
>>> > linux kernel. What I have understood is that
>>> > The task marks itself as sleeping,
>>> > puts itself on a wait queue,
>>> > removes itself from the red-black tree of runnable, and
>>> > calls schedule() to select a new process to execute.
>>> >
>>> > for Waking back up
>>> > The task is set as runnable,
>>> > removed from the wait queue,
>>> > and added back to the red-black tree.
>>> >
>>> > Can I get the details of which function does what? in sched/core.c and
>>> in
>>> > sched/fair.c
>>> > I am concerned only with fair scheduler. There are so many functions in
>>> > these two files that I am totally confused.
>>>
>>> Then core.c and fair.c is the best bet.
>>>
>>> You could also pick up a copy of Linux kernel development (By Love), it
>>> gives a nice introduction to the overall flow of .. well mostly
>>> everything.
>>> :)
>>>
>>> In kernel/sched/sched.h you have a struct called 'struct sched_class"
>>> which
>>> is a set of function-points. This is used by the core machinery to call
>>> into scheduling-class specific code. At the bottom of fair.c, you see
>>> said
>>> struct being populated.
>>>
>>> Also, if you want to see what really happens, try enabling
>>> function-tracing, but limit it to sched-functions only (and sched-events,
>>> those are also useful to see what triggers things)
>>>
>>> mount -t debugfs nodev /sys/kernel/debug
>>> cd /sys/kernel/debug/tracing
>>> echo 0 > tracing_on
>>> echo function > current_tracer
>>> echo "sched*" > set_ftrace_filter
>>> echo 1 > events/sched/enable
>>> echo 1 > tracing_on
>>> ... wait for a few secs
>>> echo 0 > tracing_on
>>>
>>> cat trace > /tmp/trace.txt
>>>
>>> Now, look at trace.txt and correlate it to the scheduler code :)
>>>
>>> Good luck!
>>>
>>> --
>>> Henrik Austad
>>>
>>
>>
>
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From yuzibode at 126.com  Mon Feb 15 09:16:48 2016
From: yuzibode at 126.com (YU Bo)
Date: Mon, 15 Feb 2016 22:16:48 +0800 (CST)
Subject: Merge conflict
In-Reply-To: <CADuXt-XGQkzhV7EUUx7TAB9hyFfKN+ir9Hs2Fr6iVM5eLD0Yxw@mail.gmail.com>
References: <50a639e9.361.152e22dc5ea.Coremail.yuzibode@126.com>
	<CAEE9rjYv7AxAeMZkVCphwW61QNi3VDyETMw+F87PdTRkAP6N6w@mail.gmail.com>
	<35d0bb5e.45d.152e243ba6a.Coremail.yuzibode@126.com>
	<57bd53d7.4b9.152e248655d.Coremail.yuzibode@126.com>
	<CADuXt-XGQkzhV7EUUx7TAB9hyFfKN+ir9Hs2Fr6iVM5eLD0Yxw@mail.gmail.com>
Message-ID: <253e29fa.3c04.152e54a762a.Coremail.yuzibode@126.com>

Hello,
At 2016-02-15 16:57:46, "Ebru Akag?nd?z" <ebru.akagunduz at gmail.com> wrote:
>Hello,
>
>>> Hi,
>>> Some days ago i followed the tips:
>>> http://kernelnewbies.org/FirstKernelPatch
>>> git clone greg's git tree and built branch first-patch.
>>> Due to my first patch that fixes coding style reported
>>> by checkptch.pl didn't applied,so i intend to rebase my
>>> git branch first-patch.The question i encounter is:
>>> ==================git command && output========
>>> yubo at debian:~/maintree/staging$  git rebase first-patch
>>> It looks like git-am is in progress. Cannot rebase.
>>> yubo at debian:~/maintree/staging$ git am --abort
>>> You seem to have moved HEAD since the last 'am' failure.
>>> Not rewinding to ORIG_HEAD
>>> yubo at debian:~/maintree/staging$ git rebase first-patch
>>> First, rewinding head to replay your work on top of it...
>>> Applying: ovl: default permissions
>>> Using index info to reconstruct a base tree...
>>> Falling back to patching base and 3-way merge...
>>> ----
>>> Auto-merging drivers/gpu/drm/i915/intel_display.c
>>> CONFLICT (content): Merge conflict in drivers/gpu/drm/i915/intel_display.c
>>> Failed to merge in the changes.
>>> Patch failed at 0010 drm/i915: Only run commit when crtc is active, v2.
>>>
>>> Is there  something with wrong?
>>> Thanks in advance for the noisy.
>
>If you would like to update your patch with newest version of the tree,
>I recommend to you, use git am. Here is the blog post:
>http://www.pizzhacks.com/bugdrome/2011/10/deal-with-git-am-failures/
>
>After updating your current tree;
>
>Firstly, you should give the command:
>1- git am your_old_patch
>
>After seeing, it could not be applied, give this:
>2- git apply PATCH --reject
>
>You'll see rejected and applied chunks, the rejected parts will be specified
>with extension .rej (with related file name). You should edit related
>files manually.
>
>3- git add fixed_files
>4- git am --resolved
>
>
>All done :). This way seems easier to me. The blog post explained
>steps, quite clear as well.

>


Thanks.  I will learn more about git.
>Kind regards,
>Ebru
>
>-- 
>Ebru Akagunduz
>http://www.ebruakagunduz.com
>
>_______________________________________________
>Kernelnewbies mailing list
>Kernelnewbies at kernelnewbies.org
>http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
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From rgroner at RTD.com  Mon Feb 15 09:44:27 2016
From: rgroner at RTD.com (Rob Groner)
Date: Mon, 15 Feb 2016 14:44:27 +0000
Subject: Finding when a chip was supported in the kernel 
Message-ID: <BY1PR0401MB1317BFE00B6D709C37F54B08A6AC0@BY1PR0401MB1317.namprd04.prod.outlook.com>


Is there some specific place/way I can find the specific kernel version when support for an arbitrary chip was added? An example is the Intel 82574 Ethernet chip.  I'm finding that google is failing me for finding the specific kernel of inclusion.  This comes up somewhat often here at work (having to determine how far back our Linux support goes), so I'm trying to find the best way to determine this.

Thank you.

Rob Groner


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From carlo at caione.org  Mon Feb 15 10:06:14 2016
From: carlo at caione.org (Carlo Caione)
Date: Mon, 15 Feb 2016 16:06:14 +0100
Subject: Finding when a chip was supported in the kernel
In-Reply-To: <BY1PR0401MB1317BFE00B6D709C37F54B08A6AC0@BY1PR0401MB1317.namprd04.prod.outlook.com>
References: <BY1PR0401MB1317BFE00B6D709C37F54B08A6AC0@BY1PR0401MB1317.namprd04.prod.outlook.com>
Message-ID: <CAOQ7t2ZU2m_Ca+XO-0fJ6oWYsqx-xRkCDdVfchVE76U9TSzWxQ@mail.gmail.com>

On Mon, Feb 15, 2016 at 3:44 PM, Rob Groner <rgroner at rtd.com> wrote:
>
>
> Is there some specific place/way I can find the specific kernel version when
> support for an arbitrary chip was added? An example is the Intel 82574
> Ethernet chip.  I?m finding that google is failing me for finding the
> specific kernel of inclusion.  This comes up somewhat often here at work
> (having to determine how far back our Linux support goes), so I?m trying to
> find the best way to determine this.

git log --reverse $driver
git describe --contains $SHA

-- 
Carlo Caione


From bjorn at mork.no  Mon Feb 15 10:43:30 2016
From: bjorn at mork.no (=?utf-8?Q?Bj=C3=B8rn_Mork?=)
Date: Mon, 15 Feb 2016 16:43:30 +0100
Subject: Finding when a chip was supported in the kernel
In-Reply-To: <CAOQ7t2ZU2m_Ca+XO-0fJ6oWYsqx-xRkCDdVfchVE76U9TSzWxQ@mail.gmail.com>
	(Carlo Caione's message of "Mon, 15 Feb 2016 16:06:14 +0100")
References: <BY1PR0401MB1317BFE00B6D709C37F54B08A6AC0@BY1PR0401MB1317.namprd04.prod.outlook.com>
	<CAOQ7t2ZU2m_Ca+XO-0fJ6oWYsqx-xRkCDdVfchVE76U9TSzWxQ@mail.gmail.com>
Message-ID: <87fuwuvv19.fsf@nemi.mork.no>

Carlo Caione <carlo at caione.org> writes:

> On Mon, Feb 15, 2016 at 3:44 PM, Rob Groner <rgroner at rtd.com> wrote:
>>
>>
>> Is there some specific place/way I can find the specific kernel version when
>> support for an arbitrary chip was added? An example is the Intel 82574
>> Ethernet chip.  I?m finding that google is failing me for finding the
>> specific kernel of inclusion.  This comes up somewhat often here at work
>> (having to determine how far back our Linux support goes), so I?m trying to
>> find the best way to determine this.
>
> git log --reverse $driver

I often find it easier to use git blame for such stuff, looking at the
dates of code related to the chip/feature in question. At least in cases
like this where a single driver supports a number of different chips.
You'll have to verify the results with "git show" of course, in case
everything was refactored.

The 82574 is a good example (since the authors made it easy with that
comment):

1st attempt returns a code refactoring commit:

bjorn at nemi:/usr/local/src/git/linux$ git log --reverse drivers/net/ethernet/intel/e1000e/82571.c
commit dee1ad47f2ee75f5146d83ca757c1b7861c34c3b
Author: Jeff Kirsher <jeffrey.t.kirsher at intel.com>
Date:   Thu Apr 7 07:42:33 2011 -0700

    intel: Move the Intel wired LAN drivers
    
    Moves the Intel wired LAN drivers into drivers/net/ethernet/intel/ and
    the necessary Kconfig and Makefile changes.
    
    Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher at intel.com>


2nd attempt returns the commit adding the driver, but that specific chip
wasn't supported (a fact which might not be easy to sport using this
method):

bjorn at nemi:/usr/local/src/git/linux$ git log --reverse dee1ad47f2ee^ -- drivers/net/e1000e/82571.c
commit bc7f75fa97884d41efbfde1397b621fefb2550b4
Author: Auke Kok <auke-jan.h.kok at intel.com>
Date:   Mon Sep 17 12:30:59 2007 -0700

    [E1000E]: New pci-express e1000 driver (currently for ICH9 devices only)
    
    This driver implements support for the ICH9 on-board LAN ethernet
    device. The device is similar to ICH8.
    
    The driver encompasses code to support 82571/2/3, es2lan and ICH8
    devices as well, but those device IDs are disabled and will be
    "lifted" from the e1000 driver over one at a time once this driver
    receives some more live time.



So you still don't know when the 82574 support was added....


git blame on the other hand, gives you this immediately:

bjorn at nemi:/usr/local/src/git/linux$ git blame drivers/net/ethernet/intel/e1000e/82571.c
e78b80b1079e1 drivers/net/ethernet/intel/e1000e/82571.c (David Ertman       2014-02-04 01:56:06 +0000    1) /* Intel PRO/1000 Linux driver
[..]
bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17 12:30:59 -0700   21) 
e921eb1ac411a drivers/net/ethernet/intel/e1000e/82571.c (Bruce Allan        2012-11-28 09:28:37 +0000   22) /* 82571EB Gigabit Ethernet Controller
1605927fcee41 drivers/net/e1000e/82571.c                (Bruce Allan        2008-11-21 16:51:06 -0800   23)  * 82571EB Gigabit Ethernet Controller (Copper)
bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17 12:30:59 -0700   24)  * 82571EB Gigabit Ethernet Controller (Fiber)
ad68076e07fa0 drivers/net/e1000e/82571.c                (Bruce Allan        2008-03-28 09:15:03 -0700   25)  * 82571EB Dual Port Gigabit Mezzanine Adapter
ad68076e07fa0 drivers/net/e1000e/82571.c                (Bruce Allan        2008-03-28 09:15:03 -0700   26)  * 82571EB Quad Port Gigabit Mezzanine Adapter
ad68076e07fa0 drivers/net/e1000e/82571.c                (Bruce Allan        2008-03-28 09:15:03 -0700   27)  * 82571PT Gigabit PT Quad Port Server ExpressMo
bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17 12:30:59 -0700   28)  * 82572EI Gigabit Ethernet Controller (Copper)
bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17 12:30:59 -0700   29)  * 82572EI Gigabit Ethernet Controller (Fiber)
bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17 12:30:59 -0700   30)  * 82572EI Gigabit Ethernet Controller
bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17 12:30:59 -0700   31)  * 82573V Gigabit Ethernet Controller (Copper)
bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17 12:30:59 -0700   32)  * 82573E Gigabit Ethernet Controller (Copper)
bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17 12:30:59 -0700   33)  * 82573L Gigabit Ethernet Controller
4662e82b2cb41 drivers/net/e1000e/82571.c                (Bruce Allan        2008-08-26 18:37:06 -0700   34)  * 82574L Gigabit Network Connection
8c81c9c315b7e drivers/net/e1000e/82571.c                (Alexander Duyck    2009-03-19 01:12:27 +0000   35)  * 82583V Gigabit Network Connection
bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17 12:30:59 -0700   36)  */
bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17 12:30:59 -0700   37) 
bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17 12:30:59 -0700   38) #include "e1000.h"



And you can verify by looking at the commit:


bjorn at nemi:/usr/local/src/git/linux$ git show 4662e82b2cb41
commit 4662e82b2cb41c60826e50474dd86dd5c6372b0c
Author: Bruce Allan <bruce.w.allan at intel.com>
Date:   Tue Aug 26 18:37:06 2008 -0700

    e1000e: add support for new 82574L part
    
    This new part has the same feature set as previous parts with the addition
    of MSI-X support.
    
    Signed-off-by: Bruce Allan <bruce.w.allan at intel.com>
    Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher at intel.com>
    Signed-off-by: Jeff Garzik <jgarzik at redhat.com>

[etc]



I'll admit that this example was extremely easy.  Most of the time you'll
have to figure out the relevant commits by looking at code lines related
to that chip.  But it's still easier to look at git blame than the log
if the support was added to an existing driver.


Bj?rn


From varyani.nitin1 at gmail.com  Mon Feb 15 11:05:28 2016
From: varyani.nitin1 at gmail.com (Nitin Varyani)
Date: Mon, 15 Feb 2016 21:35:28 +0530
Subject: Distributed Process Scheduling Algorithm
Message-ID: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>

 Hi,
I am given a task to design a distributed process scheduling algorithm.
Current distributed OS are patch work over the linux kernels, that is, they
are responsible for load balancing through process migration but the
scheduling is taken care by the single machine linux kernels. My task is to
make the scheduling algorithm itself as distributed. That is a scheduler
itself makes a decision whether to migrate a task or to keep the task in
the current system.  I need some design aspects of how to achieve it.
Another thing which I want to know is that whether this job is possible for
a kernel newbie like me. Need urgent help.
Nitin
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From rgroner at RTD.com  Mon Feb 15 11:06:54 2016
From: rgroner at RTD.com (Rob Groner)
Date: Mon, 15 Feb 2016 16:06:54 +0000
Subject: Finding when a chip was supported in the kernel
In-Reply-To: <87fuwuvv19.fsf@nemi.mork.no>
References: <BY1PR0401MB1317BFE00B6D709C37F54B08A6AC0@BY1PR0401MB1317.namprd04.prod.outlook.com>
	<CAOQ7t2ZU2m_Ca+XO-0fJ6oWYsqx-xRkCDdVfchVE76U9TSzWxQ@mail.gmail.com>
	<87fuwuvv19.fsf@nemi.mork.no>
Message-ID: <BY1PR0401MB1317565AC70EBE07056EA957A6AC0@BY1PR0401MB1317.namprd04.prod.outlook.com>


> -----Original Message-----
> From: Bj?rn Mork [mailto:bjorn at mork.no]
> Sent: Monday, February 15, 2016 10:44 AM
> To: Carlo Caione <carlo at caione.org>
> Cc: Rob Groner <rgroner at RTD.com>; kernelnewbies at kernelnewbies.org
> Subject: Re: Finding when a chip was supported in the kernel
> 
> Carlo Caione <carlo at caione.org> writes:
> 
> > On Mon, Feb 15, 2016 at 3:44 PM, Rob Groner <rgroner at rtd.com> wrote:
> >>
<snip>
> 
> git blame on the other hand, gives you this immediately:
> 
> bjorn at nemi:/usr/local/src/git/linux$ git blame
> drivers/net/ethernet/intel/e1000e/82571.c
> e78b80b1079e1 drivers/net/ethernet/intel/e1000e/82571.c (David Ertman
> 2014-02-04 01:56:06 +0000    1) /* Intel PRO/1000 Linux driver
> [..]
> bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17
> 12:30:59 -0700   21)
> e921eb1ac411a drivers/net/ethernet/intel/e1000e/82571.c (Bruce Allan
> 2012-11-28 09:28:37 +0000   22) /* 82571EB Gigabit Ethernet Controller
> 1605927fcee41 drivers/net/e1000e/82571.c                (Bruce Allan        2008-11-
> 21 16:51:06 -0800   23)  * 82571EB Gigabit Ethernet Controller (Copper)
> bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17
> 12:30:59 -0700   24)  * 82571EB Gigabit Ethernet Controller (Fiber)
> ad68076e07fa0 drivers/net/e1000e/82571.c                (Bruce Allan        2008-03-
> 28 09:15:03 -0700   25)  * 82571EB Dual Port Gigabit Mezzanine Adapter
> ad68076e07fa0 drivers/net/e1000e/82571.c                (Bruce Allan        2008-03-
> 28 09:15:03 -0700   26)  * 82571EB Quad Port Gigabit Mezzanine Adapter
> ad68076e07fa0 drivers/net/e1000e/82571.c                (Bruce Allan        2008-03-
> 28 09:15:03 -0700   27)  * 82571PT Gigabit PT Quad Port Server ExpressMo
> bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17
> 12:30:59 -0700   28)  * 82572EI Gigabit Ethernet Controller (Copper)
> bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17
> 12:30:59 -0700   29)  * 82572EI Gigabit Ethernet Controller (Fiber)
> bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17
> 12:30:59 -0700   30)  * 82572EI Gigabit Ethernet Controller
> bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17
> 12:30:59 -0700   31)  * 82573V Gigabit Ethernet Controller (Copper)
> bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17
> 12:30:59 -0700   32)  * 82573E Gigabit Ethernet Controller (Copper)
> bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17
> 12:30:59 -0700   33)  * 82573L Gigabit Ethernet Controller
> 4662e82b2cb41 drivers/net/e1000e/82571.c                (Bruce Allan        2008-08-
> 26 18:37:06 -0700   34)  * 82574L Gigabit Network Connection
> 8c81c9c315b7e drivers/net/e1000e/82571.c                (Alexander Duyck    2009-
> 03-19 01:12:27 +0000   35)  * 82583V Gigabit Network Connection
> bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17
> 12:30:59 -0700   36)  */
> bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17
> 12:30:59 -0700   37)
> bc7f75fa97884 drivers/net/e1000e/82571.c                (Auke Kok           2007-09-17
> 12:30:59 -0700   38) #include "e1000.h"
> 
> 
> 
> And you can verify by looking at the commit:
> 
> 
> bjorn at nemi:/usr/local/src/git/linux$ git show 4662e82b2cb41 commit
> 4662e82b2cb41c60826e50474dd86dd5c6372b0c
> Author: Bruce Allan <bruce.w.allan at intel.com>
> Date:   Tue Aug 26 18:37:06 2008 -0700
> 
>     e1000e: add support for new 82574L part
> 
>     This new part has the same feature set as previous parts with the addition
>     of MSI-X support.
> 
>     Signed-off-by: Bruce Allan <bruce.w.allan at intel.com>
>     Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher at intel.com>
>     Signed-off-by: Jeff Garzik <jgarzik at redhat.com>
> 
> [etc]
> 
> 
> 
> I'll admit that this example was extremely easy.  Most of the time you'll have
> to figure out the relevant commits by looking at code lines related to that
> chip.  But it's still easier to look at git blame than the log if the support was
> added to an existing driver.
> 

Hmm...I don't think I share the idea that it was extremely easy.  :)  But it is something I can try at least, assuming I can get at least as far as figuring out which driver file a particular chip gets its support from.  With Intel chips, that IS pretty easy.

Using the blame I see that it gives a date and a commit reference.  How do I then correlate that to the kernel version where it first showed up?  I'm assuming there's a git command for showing that.

Rob


From henrik at austad.us  Mon Feb 15 11:52:31 2016
From: henrik at austad.us (Henrik Austad)
Date: Mon, 15 Feb 2016 17:52:31 +0100
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>
References: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>
Message-ID: <20160215165231.GD21526@icarus.home.austad.us>

On Mon, Feb 15, 2016 at 09:35:28PM +0530, Nitin Varyani wrote:
>  Hi,

Hi Nitin,

> I am given a task to design a distributed process scheduling algorithm.
> Current distributed OS are patch work over the linux kernels, that is, they
> are responsible for load balancing through process migration but the
> scheduling is taken care by the single machine linux kernels.

Hmm, are you talking about HPC clusters or other large machines here? I'm 
not familiar with this, so a few references to existing designs would be 
appreciated.

> My task is to make the scheduling algorithm itself as distributed. 

Apart from my comment below, it sounds like a really interesting project. 
Is this a research-project or something commercial?

> That is a scheduler itself makes a decision whether to migrate a task or 
> to keep the task in the current system.  I need some design aspects of 
> how to achieve it. Another thing which I want to know is that whether 
> this job is possible for a kernel newbie like me. Need urgent help. Nitin

Uhm, ok. I think this is _way_ outside the scope of Kernelnewbies, and it 
is definitely not a newbie project.

If you are really serious about this, I'd start with listing all the 
different elements you need to share and then an initial idea as to how to 
share those between individual systems. I have an inkling that you'll find 
out quite fast as to why the current kernel does not support this out of 
the box.

-- 
Henrik Austad
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From bjorn at mork.no  Mon Feb 15 12:04:55 2016
From: bjorn at mork.no (=?utf-8?Q?Bj=C3=B8rn_Mork?=)
Date: Mon, 15 Feb 2016 18:04:55 +0100
Subject: Finding when a chip was supported in the kernel
In-Reply-To: <BY1PR0401MB1317565AC70EBE07056EA957A6AC0@BY1PR0401MB1317.namprd04.prod.outlook.com>
	(Rob Groner's message of "Mon, 15 Feb 2016 16:06:54 +0000")
References: <BY1PR0401MB1317BFE00B6D709C37F54B08A6AC0@BY1PR0401MB1317.namprd04.prod.outlook.com>
	<CAOQ7t2ZU2m_Ca+XO-0fJ6oWYsqx-xRkCDdVfchVE76U9TSzWxQ@mail.gmail.com>
	<87fuwuvv19.fsf@nemi.mork.no>
	<BY1PR0401MB1317565AC70EBE07056EA957A6AC0@BY1PR0401MB1317.namprd04.prod.outlook.com>
Message-ID: <87bn7hx5u0.fsf@nemi.mork.no>

Rob Groner <rgroner at RTD.com> writes:

> Hmm...I don't think I share the idea that it was extremely easy.  :)

OK :)

> But it is something I can try at least, assuming I can get at least as
> far as figuring out which driver file a particular chip gets its
> support from.  With Intel chips, that IS pretty easy.
>
> Using the blame I see that it gives a date and a commit reference.
> How do I then correlate that to the kernel version where it first
> showed up?  I'm assuming there's a git command for showing that.

That was the other command Carlo gave, which I failed to quote.  Sorry
about that. Carlo wrote:

> git describe --contains $SHA

e.g

bjorn at nemi:/usr/local/src/git/linux$  git describe --contains 4662e82b2cb41
v2.6.28-rc1~717^2~323



Bj?rn


From rgroner at RTD.com  Mon Feb 15 12:12:53 2016
From: rgroner at RTD.com (Rob Groner)
Date: Mon, 15 Feb 2016 17:12:53 +0000
Subject: Finding when a chip was supported in the kernel
In-Reply-To: <87bn7hx5u0.fsf@nemi.mork.no>
References: <BY1PR0401MB1317BFE00B6D709C37F54B08A6AC0@BY1PR0401MB1317.namprd04.prod.outlook.com>
	<CAOQ7t2ZU2m_Ca+XO-0fJ6oWYsqx-xRkCDdVfchVE76U9TSzWxQ@mail.gmail.com>
	<87fuwuvv19.fsf@nemi.mork.no>
	<BY1PR0401MB1317565AC70EBE07056EA957A6AC0@BY1PR0401MB1317.namprd04.prod.outlook.com>
	<87bn7hx5u0.fsf@nemi.mork.no>
Message-ID: <BY1PR0401MB13171DF5E5AC12941BA553B3A6AC0@BY1PR0401MB1317.namprd04.prod.outlook.com>


> -----Original Message-----
> From: Bj?rn Mork [mailto:bjorn at mork.no]
> Sent: Monday, February 15, 2016 12:05 PM
> To: Rob Groner <rgroner at RTD.com>
> Cc: Carlo Caione <carlo at caione.org>; kernelnewbies at kernelnewbies.org
> Subject: Re: Finding when a chip was supported in the kernel
> 
> Rob Groner <rgroner at RTD.com> writes:
> 
> > Hmm...I don't think I share the idea that it was extremely easy.  :)
> 
> OK :)
> 
> > But it is something I can try at least, assuming I can get at least as
> > far as figuring out which driver file a particular chip gets its
> > support from.  With Intel chips, that IS pretty easy.
> >
> > Using the blame I see that it gives a date and a commit reference.
> > How do I then correlate that to the kernel version where it first
> > showed up?  I'm assuming there's a git command for showing that.
> 
> That was the other command Carlo gave, which I failed to quote.  Sorry about
> that. Carlo wrote:
> 
> > git describe --contains $SHA
> 
> e.g
> 
> bjorn at nemi:/usr/local/src/git/linux$  git describe --contains 4662e82b2cb41
> v2.6.28-rc1~717^2~323
> 

Great, thank you!

Rob


From Valdis.Kletnieks at vt.edu  Mon Feb 15 22:37:56 2016
From: Valdis.Kletnieks at vt.edu (Valdis.Kletnieks at vt.edu)
Date: Mon, 15 Feb 2016 22:37:56 -0500
Subject: Finding when a chip was supported in the kernel
In-Reply-To: <BY1PR0401MB1317565AC70EBE07056EA957A6AC0@BY1PR0401MB1317.namprd04.prod.outlook.com>
References: <BY1PR0401MB1317BFE00B6D709C37F54B08A6AC0@BY1PR0401MB1317.namprd04.prod.outlook.com>
	<CAOQ7t2ZU2m_Ca+XO-0fJ6oWYsqx-xRkCDdVfchVE76U9TSzWxQ@mail.gmail.com>
	<87fuwuvv19.fsf@nemi.mork.no>
	<BY1PR0401MB1317565AC70EBE07056EA957A6AC0@BY1PR0401MB1317.namprd04.prod.outlook.com>
Message-ID: <35346.1455593876@turing-police.cc.vt.edu>

On Mon, 15 Feb 2016 16:06:54 +0000, Rob Groner said:

> > bjorn at nemi:/usr/local/src/git/linux$ git show 4662e82b2cb41
> > commit 4662e82b2cb41c60826e50474dd86dd5c6372b0c
> > Author: Bruce Allan <bruce.w.allan at intel.com>
> > Date:   Tue Aug 26 18:37:06 2008 -0700


> Using the blame I see that it gives a date and a commit reference.  How do I 
> then correlate that to the kernel version where it first showed up?  I'm
> assuming there's a git command for showing that.

git tag --contains 4662e82b2cb41

should do the job for you.

Note:  They're sorted lexically, not in release order - so v3.21 through v3.29
are hiding between v3.2 and v3.3,
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From varyani.nitin1 at gmail.com  Mon Feb 15 23:48:26 2016
From: varyani.nitin1 at gmail.com (Nitin Varyani)
Date: Tue, 16 Feb 2016 10:18:26 +0530
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <20160215165231.GD21526@icarus.home.austad.us>
References: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>
	<20160215165231.GD21526@icarus.home.austad.us>
Message-ID: <CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>

No doubt it is really interesting. It is a research project. The project is
related to HPC clusters. I am as of now planning only to make the process
scheduling algorithm distributed. Linux has already implemented SMP using
Completely Fair Scheduler and I was thinking was of extending it for
distributed systems. Two things need to be added to it:
1) Sending process context via network
2) Maintaining a table at each node which stores the load of each remote
node. This table will be used to make a decision whether to send a process
context along the network or not. Thanks for your kind help.


On Mon, Feb 15, 2016 at 10:22 PM, Henrik Austad <henrik at austad.us> wrote:

> On Mon, Feb 15, 2016 at 09:35:28PM +0530, Nitin Varyani wrote:
> >  Hi,
>
> Hi Nitin,
>
> > I am given a task to design a distributed process scheduling algorithm.
> > Current distributed OS are patch work over the linux kernels, that is,
> they
> > are responsible for load balancing through process migration but the
> > scheduling is taken care by the single machine linux kernels.
>
> Hmm, are you talking about HPC clusters or other large machines here? I'm
> not familiar with this, so a few references to existing designs would be
> appreciated.
>
> > My task is to make the scheduling algorithm itself as distributed.
>
> Apart from my comment below, it sounds like a really interesting project.
> Is this a research-project or something commercial?
>
> > That is a scheduler itself makes a decision whether to migrate a task or
> > to keep the task in the current system.  I need some design aspects of
> > how to achieve it. Another thing which I want to know is that whether
> > this job is possible for a kernel newbie like me. Need urgent help. Nitin
>
> Uhm, ok. I think this is _way_ outside the scope of Kernelnewbies, and it
> is definitely not a newbie project.
>
> If you are really serious about this, I'd start with listing all the
> different elements you need to share and then an initial idea as to how to
> share those between individual systems. I have an inkling that you'll find
> out quite fast as to why the current kernel does not support this out of
> the box.
>
> --
> Henrik Austad
>
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From Valdis.Kletnieks at vt.edu  Tue Feb 16 00:13:34 2016
From: Valdis.Kletnieks at vt.edu (Valdis.Kletnieks at vt.edu)
Date: Tue, 16 Feb 2016 00:13:34 -0500
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>
References: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>
	<20160215165231.GD21526@icarus.home.austad.us>
	<CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>
Message-ID: <42173.1455599614@turing-police.cc.vt.edu>

On Tue, 16 Feb 2016 10:18:26 +0530, Nitin Varyani said:

> 1) Sending process context via network

Note that this is a non-trivial issue by itself.  At a *minimum*,
you'll need all the checkpoint-restart code.  Plus, if the process
has any open TCP connections, *those* have to be migrated without
causing a security problem.  Good luck on figuring out how to properly
route packets in this case - consider 4 nodes 10.0.0.1 through 10.0.0.4,
you migrate a process from 10.0.0.1 to 10.0.0.3,  How do you make sure
*that process*'s packets go to 0.3 while all other packets still go to
0.1.  Also, consider the impact this may have on iptables, if there is
a state=RELATED,CONNECTED on 0.1 - that info needs to be relayed to 0.3
as well.

For bonus points, what's the most efficient way to transfer a large
process image (say 500M, or even a bloated Firefox at 3.5G), without
causing timeouts while copying the image?

I hope your research project is *really* well funded - you're going
to need a *lot* of people (Hint - find out how many people work on
VMWare - that should give you a rough idea)
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From dingel at linux.vnet.ibm.com  Tue Feb 16 03:42:52 2016
From: dingel at linux.vnet.ibm.com (Dominik Dingel)
Date: Tue, 16 Feb 2016 09:42:52 +0100
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <42173.1455599614@turing-police.cc.vt.edu>
References: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>
	<20160215165231.GD21526@icarus.home.austad.us>
	<CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>
	<42173.1455599614@turing-police.cc.vt.edu>
Message-ID: <20160216094252.194c7907@BR9TG4T3.de.ibm.com>

On Tue, 16 Feb 2016 00:13:34 -0500
Valdis.Kletnieks at vt.edu wrote:

> On Tue, 16 Feb 2016 10:18:26 +0530, Nitin Varyani said:
> 
> > 1) Sending process context via network
> 
> Note that this is a non-trivial issue by itself.  At a *minimum*,
> you'll need all the checkpoint-restart code.  Plus, if the process
> has any open TCP connections, *those* have to be migrated without
> causing a security problem.  Good luck on figuring out how to properly
> route packets in this case - consider 4 nodes 10.0.0.1 through 10.0.0.4,
> you migrate a process from 10.0.0.1 to 10.0.0.3,  How do you make sure
> *that process*'s packets go to 0.3 while all other packets still go to
> 0.1.  Also, consider the impact this may have on iptables, if there is
> a state=RELATED,CONNECTED on 0.1 - that info needs to be relayed to 0.3
> as well.
> 
> For bonus points, what's the most efficient way to transfer a large
> process image (say 500M, or even a bloated Firefox at 3.5G), without
> causing timeouts while copying the image?
> 
> I hope your research project is *really* well funded - you're going
> to need a *lot* of people (Hint - find out how many people work on
> VMWare - that should give you a rough idea)

I wouldn't see things that dark. Also this is an interesting puzzle.

To migrate processes I would pick an already existing solution.
Like there is for container. So every process should be, if possible, in a container.
To migrate them efficiently without having some distributed shared memory,
you might want to look at userfaultfd.

So now back to the scheduling, I do not think that every node should keep track
of every process on every other node, as this would mean a massive need for
communication and hurt scalability. So either you would implement something like work stealing or go for a central entity like mesos. Which could do process/job/container scheduling for you.

There are now two pitfalls which are hard enough on their own:
- interprocess communication between two process with something different than a socket
  in such an case you would probably need to merge the two distinct containers

- dedicated hardware

Dominik



From varyani.nitin1 at gmail.com  Tue Feb 16 04:46:17 2016
From: varyani.nitin1 at gmail.com (Nitin Varyani)
Date: Tue, 16 Feb 2016 15:16:17 +0530
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <20160216094252.194c7907@BR9TG4T3.de.ibm.com>
References: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>
	<20160215165231.GD21526@icarus.home.austad.us>
	<CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>
	<42173.1455599614@turing-police.cc.vt.edu>
	<20160216094252.194c7907@BR9TG4T3.de.ibm.com>
Message-ID: <CAKfJ7KLiqamnjXoi0TKg9udw+1hCZ_WQKLWKnvDhNnhiudwyUw@mail.gmail.com>

According to my project requirement, I need a distributed algorithm so
mesos will not work. But work stealing is the best bargain. It will save
communication costs. Thankyou. Can you please elaborate on the last part of
your reply?

On Tue, Feb 16, 2016 at 2:12 PM, Dominik Dingel <dingel at linux.vnet.ibm.com>
wrote:

> On Tue, 16 Feb 2016 00:13:34 -0500
> Valdis.Kletnieks at vt.edu wrote:
>
> > On Tue, 16 Feb 2016 10:18:26 +0530, Nitin Varyani said:
> >
> > > 1) Sending process context via network
> >
> > Note that this is a non-trivial issue by itself.  At a *minimum*,
> > you'll need all the checkpoint-restart code.  Plus, if the process
> > has any open TCP connections, *those* have to be migrated without
> > causing a security problem.  Good luck on figuring out how to properly
> > route packets in this case - consider 4 nodes 10.0.0.1 through 10.0.0.4,
> > you migrate a process from 10.0.0.1 to 10.0.0.3,  How do you make sure
> > *that process*'s packets go to 0.3 while all other packets still go to
> > 0.1.  Also, consider the impact this may have on iptables, if there is
> > a state=RELATED,CONNECTED on 0.1 - that info needs to be relayed to 0.3
> > as well.
> >
> > For bonus points, what's the most efficient way to transfer a large
> > process image (say 500M, or even a bloated Firefox at 3.5G), without
> > causing timeouts while copying the image?
> >
> > I hope your research project is *really* well funded - you're going
> > to need a *lot* of people (Hint - find out how many people work on
> > VMWare - that should give you a rough idea)
>
> I wouldn't see things that dark. Also this is an interesting puzzle.
>
> To migrate processes I would pick an already existing solution.
> Like there is for container. So every process should be, if possible, in a
> container.
> To migrate them efficiently without having some distributed shared memory,
> you might want to look at userfaultfd.
>
> So now back to the scheduling, I do not think that every node should keep
> track
> of every process on every other node, as this would mean a massive need for
> communication and hurt scalability. So either you would implement
> something like work stealing or go for a central entity like mesos. Which
> could do process/job/container scheduling for you.
>
> There are now two pitfalls which are hard enough on their own:
> - interprocess communication between two process with something different
> than a socket
>   in such an case you would probably need to merge the two distinct
> containers
>
> - dedicated hardware
>
> Dominik
>
>
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From varyani.nitin1 at gmail.com  Tue Feb 16 05:43:25 2016
From: varyani.nitin1 at gmail.com (Nitin Varyani)
Date: Tue, 16 Feb 2016 16:13:25 +0530
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <CAKfJ7KLiqamnjXoi0TKg9udw+1hCZ_WQKLWKnvDhNnhiudwyUw@mail.gmail.com>
References: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>
	<20160215165231.GD21526@icarus.home.austad.us>
	<CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>
	<42173.1455599614@turing-police.cc.vt.edu>
	<20160216094252.194c7907@BR9TG4T3.de.ibm.com>
	<CAKfJ7KLiqamnjXoi0TKg9udw+1hCZ_WQKLWKnvDhNnhiudwyUw@mail.gmail.com>
Message-ID: <CAKfJ7KK_eYn7OD4VknHSYmeiK2vR+90RN79BW2QMc1y3ZM3T5Q@mail.gmail.com>

The essence of the discussion is that :

We can run each process in a container and migrate the container itself.
Migration can be done based on work stealing. As far as communication
between processes in different containers is concerned, can't we use
sockets?

On Tue, Feb 16, 2016 at 3:16 PM, Nitin Varyani <varyani.nitin1 at gmail.com>
wrote:

> According to my project requirement, I need a distributed algorithm so
> mesos will not work. But work stealing is the best bargain. It will save
> communication costs. Thankyou. Can you please elaborate on the last part of
> your reply?
>
> On Tue, Feb 16, 2016 at 2:12 PM, Dominik Dingel <dingel at linux.vnet.ibm.com
> > wrote:
>
>> On Tue, 16 Feb 2016 00:13:34 -0500
>> Valdis.Kletnieks at vt.edu wrote:
>>
>> > On Tue, 16 Feb 2016 10:18:26 +0530, Nitin Varyani said:
>> >
>> > > 1) Sending process context via network
>> >
>> > Note that this is a non-trivial issue by itself.  At a *minimum*,
>> > you'll need all the checkpoint-restart code.  Plus, if the process
>> > has any open TCP connections, *those* have to be migrated without
>> > causing a security problem.  Good luck on figuring out how to properly
>> > route packets in this case - consider 4 nodes 10.0.0.1 through 10.0.0.4,
>> > you migrate a process from 10.0.0.1 to 10.0.0.3,  How do you make sure
>> > *that process*'s packets go to 0.3 while all other packets still go to
>> > 0.1.  Also, consider the impact this may have on iptables, if there is
>> > a state=RELATED,CONNECTED on 0.1 - that info needs to be relayed to 0.3
>> > as well.
>> >
>> > For bonus points, what's the most efficient way to transfer a large
>> > process image (say 500M, or even a bloated Firefox at 3.5G), without
>> > causing timeouts while copying the image?
>> >
>> > I hope your research project is *really* well funded - you're going
>> > to need a *lot* of people (Hint - find out how many people work on
>> > VMWare - that should give you a rough idea)
>>
>> I wouldn't see things that dark. Also this is an interesting puzzle.
>>
>> To migrate processes I would pick an already existing solution.
>> Like there is for container. So every process should be, if possible, in
>> a container.
>> To migrate them efficiently without having some distributed shared memory,
>> you might want to look at userfaultfd.
>>
>> So now back to the scheduling, I do not think that every node should keep
>> track
>> of every process on every other node, as this would mean a massive need
>> for
>> communication and hurt scalability. So either you would implement
>> something like work stealing or go for a central entity like mesos. Which
>> could do process/job/container scheduling for you.
>>
>> There are now two pitfalls which are hard enough on their own:
>> - interprocess communication between two process with something different
>> than a socket
>>   in such an case you would probably need to merge the two distinct
>> containers
>>
>> - dedicated hardware
>>
>> Dominik
>>
>>
>
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From dingel at linux.vnet.ibm.com  Tue Feb 16 06:22:17 2016
From: dingel at linux.vnet.ibm.com (Dominik Dingel)
Date: Tue, 16 Feb 2016 12:22:17 +0100
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <CAKfJ7KK_eYn7OD4VknHSYmeiK2vR+90RN79BW2QMc1y3ZM3T5Q@mail.gmail.com>
References: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>
	<20160215165231.GD21526@icarus.home.austad.us>
	<CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>
	<42173.1455599614@turing-police.cc.vt.edu>
	<20160216094252.194c7907@BR9TG4T3.de.ibm.com>
	<CAKfJ7KLiqamnjXoi0TKg9udw+1hCZ_WQKLWKnvDhNnhiudwyUw@mail.gmail.com>
	<CAKfJ7KK_eYn7OD4VknHSYmeiK2vR+90RN79BW2QMc1y3ZM3T5Q@mail.gmail.com>
Message-ID: <20160216122217.21c6096e@BR9TG4T3.de.ibm.com>

On Tue, 16 Feb 2016 16:13:25 +0530
Nitin Varyani <varyani.nitin1 at gmail.com> wrote:

It is common practice to shorten your answers to mailinglists.

> The essence of the discussion is that :
> 
> We can run each process in a container and migrate the container itself.
> Migration can be done based on work stealing. As far as communication
> between processes in different containers is concerned, can't we use
> sockets?
> 

Migration can be done based on work stealing sounds misleading. Maybe something like:
Nodes might apply the work stealing pattern by migrating the workload, encapsulated in the container.

That would be the idea, if that actually works and how it would perform is up to that experiment ;).

That is for new applications possible, but there may be "legacy" applications which rely on communication methods like shared memory, and pipes.

If this ends in an research paper I would like to read it.

Dominik



From newell.roger at gmail.com  Tue Feb 16 08:38:23 2016
From: newell.roger at gmail.com (Roger H Newell)
Date: Tue, 16 Feb 2016 10:08:23 -0330
Subject: Patch Series
Message-ID: <CAEE9rjahhbnLxFAu0nnb2AOQzo8D0J7_tHS3xPuo56hrJx75FQ@mail.gmail.com>

Hi all:

I have a question about creating a patch series. I'm working in
drivers/staging/wilc1000 fixing code style. If for example 2 errors are
reported by checkpatch.pl error A and error B, it seems logical that I
could fix all occurrences of error A as one patch and all occurrences of
error B in a second patch.

My question is, is it OK to fix all occurrences of error A across the files
inside drivers/staging/wilc1000 as one patch and all occurrences of error B
across all files inside drivers/staging/wilc1000 as a second patch?

The alternative would be to create a patch that fixes all errors of A and a
patch that fixes all errors of B per file ? In some cases there are so many
occurrences of a particular error across files it probably does make more
sense to create the patches per file.

Any thoughts or clarifications on this ?

Cheers:
Roger H. Newell
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From geyslan at gmail.com  Tue Feb 16 08:52:35 2016
From: geyslan at gmail.com (Geyslan G. Bem)
Date: Tue, 16 Feb 2016 10:52:35 -0300
Subject: Patch Series
In-Reply-To: <CAEE9rjahhbnLxFAu0nnb2AOQzo8D0J7_tHS3xPuo56hrJx75FQ@mail.gmail.com>
References: <CAEE9rjahhbnLxFAu0nnb2AOQzo8D0J7_tHS3xPuo56hrJx75FQ@mail.gmail.com>
Message-ID: <CAGG-pUSYP=MyDkz2P7R=vdr8X4--==q_qfH970gj=YXz+bCFNQ@mail.gmail.com>

Hello,

2016-02-16 10:38 GMT-03:00 Roger H Newell <newell.roger at gmail.com>:
> Hi all:
>
> I have a question about creating a patch series. I'm working in
> drivers/staging/wilc1000 fixing code style. If for example 2 errors are
> reported by checkpatch.pl error A and error B, it seems logical that I could
> fix all occurrences of error A as one patch and all occurrences of error B
> in a second patch.
>
> My question is, is it OK to fix all occurrences of error A across the files
> inside drivers/staging/wilc1000 as one patch and all occurrences of error B
> across all files inside drivers/staging/wilc1000 as a second patch?

I think it is. But you must rely on the maintainer's choice. Ask
him/her before sending.

>
> The alternative would be to create a patch that fixes all errors of A and a
> patch that fixes all errors of B per file ? In some cases there are so many
> occurrences of a particular error across files it probably does make more
> sense to create the patches per file.
>
> Any thoughts or clarifications on this ?

Ditto. But each case must be evaluated. Some changes (error A and B)
can be done in one line, so you have to analyze them.
A real case would be nice for a better exemplification.
>
> Cheers:
> Roger H. Newell
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>



-- 
Regards,

Geyslan G. Bem
hackingbits.com


From Valdis.Kletnieks at vt.edu  Tue Feb 16 11:35:11 2016
From: Valdis.Kletnieks at vt.edu (Valdis.Kletnieks at vt.edu)
Date: Tue, 16 Feb 2016 11:35:11 -0500
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <20160216094252.194c7907@BR9TG4T3.de.ibm.com>
References: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>
	<20160215165231.GD21526@icarus.home.austad.us>
	<CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>
	<42173.1455599614@turing-police.cc.vt.edu>
	<20160216094252.194c7907@BR9TG4T3.de.ibm.com>
Message-ID: <124507.1455640511@turing-police.cc.vt.edu>

On Tue, 16 Feb 2016 09:42:52 +0100, Dominik Dingel said:

> I wouldn't see things that dark. Also this is an interesting puzzle.

Just pointing out *very real* issues that will require solution, unless
you add strict bounds like "cannot be using network connections".

Heck, even open files get interesting.  How do you ensure that the
file descriptor returned by mkstemp() remains valid? (The *really*
ugly case is programs that do a mkstemp() and then unlink() the result,
confident that the kernel will clean up when the process exits, as
there is no longer a file system object to reference....

Of course, if you say "no network connections" and "no open files",
the problem gets a lot easier - but also quickly devolving into a
master's thesis research project rather than anything useful....

Bottom line:  Don't even *think* about changing the scheduler etc
until you have a functional way to actually move the process.  Doesn't
matter if you use a kvm approach, or containers, or whatever - if
you can't do the migrate, you can't even *test* your code that decides
which process to migrate.....
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From varyani.nitin1 at gmail.com  Tue Feb 16 23:51:35 2016
From: varyani.nitin1 at gmail.com (Nitin Varyani)
Date: Wed, 17 Feb 2016 10:21:35 +0530
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <124507.1455640511@turing-police.cc.vt.edu>
References: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>
	<20160215165231.GD21526@icarus.home.austad.us>
	<CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>
	<42173.1455599614@turing-police.cc.vt.edu>
	<20160216094252.194c7907@BR9TG4T3.de.ibm.com>
	<124507.1455640511@turing-police.cc.vt.edu>
Message-ID: <CAKfJ7KKxoh3a-Yw4c+5Kf42gWxMiGam3JJ3u=HyhJ=uA7uMdoQ@mail.gmail.com>

if you say "no network connections" and "no open files",
the problem gets a lot easier - but also quickly devolving into a
master's thesis research project rather than anything useful....

Actually it is a master's thesis research project as of now. I am ready to
boil down to the most basic implementation of distributed linux kernel.
Assume there is no network connection and no open files. We can drop even
more assumptions if it becomes complicated. Once this basic implementation
is successful, we can go ahead with a more complicated version. The next
task is to integrate the migration code in the linux kernel. What is the
most easy way of implementing it.

On Tue, Feb 16, 2016 at 10:05 PM, <Valdis.Kletnieks at vt.edu> wrote:

> On Tue, 16 Feb 2016 09:42:52 +0100, Dominik Dingel said:
>
> > I wouldn't see things that dark. Also this is an interesting puzzle.
>
> Just pointing out *very real* issues that will require solution, unless
> you add strict bounds like "cannot be using network connections".
>
> Heck, even open files get interesting.  How do you ensure that the
> file descriptor returned by mkstemp() remains valid? (The *really*
> ugly case is programs that do a mkstemp() and then unlink() the result,
> confident that the kernel will clean up when the process exits, as
> there is no longer a file system object to reference....
>
> Of course, if you say "no network connections" and "no open files",
> the problem gets a lot easier - but also quickly devolving into a
> master's thesis research project rather than anything useful....
>
> Bottom line:  Don't even *think* about changing the scheduler etc
> until you have a functional way to actually move the process.  Doesn't
> matter if you use a kvm approach, or containers, or whatever - if
> you can't do the migrate, you can't even *test* your code that decides
> which process to migrate.....
>
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From yuzibode at 126.com  Wed Feb 17 00:00:12 2016
From: yuzibode at 126.com (YU Bo)
Date: Wed, 17 Feb 2016 13:00:12 +0800 (CST)
Subject: Patch Series
In-Reply-To: <CAGG-pUSYP=MyDkz2P7R=vdr8X4--==q_qfH970gj=YXz+bCFNQ@mail.gmail.com>
References: <CAEE9rjahhbnLxFAu0nnb2AOQzo8D0J7_tHS3xPuo56hrJx75FQ@mail.gmail.com>
	<CAGG-pUSYP=MyDkz2P7R=vdr8X4--==q_qfH970gj=YXz+bCFNQ@mail.gmail.com>
Message-ID: <65fa18ad.43fb.152ed99983e.Coremail.yuzibode@126.com>







--
Best Regards




At 2016-02-16 21:52:35, "Geyslan G. Bem" <geyslan at gmail.com> wrote:
>Hello,
>
>2016-02-16 10:38 GMT-03:00 Roger H Newell <newell.roger at gmail.com>:
>> Hi all:
>>
>> I have a question about creating a patch series. I'm working in
>> drivers/staging/wilc1000 fixing code style. If for example 2 errors are
>> reported by checkpatch.pl error A and error B, it seems logical that I could
>> fix all occurrences of error A as one patch and all occurrences of error B
>> in a second patch.
>>
>> My question is, is it OK to fix all occurrences of error A across the files
>> inside drivers/staging/wilc1000 as one patch and all occurrences of error B
>> across all files inside drivers/staging/wilc1000 as a second patch?
>
>I think it is. But you must rely on the maintainer's choice. Ask

>him/her before sending.
Greg said that per patch resolve per issue.Maybe i am wrong..:)
>
>>
>> The alternative would be to create a patch that fixes all errors of A and a
>> patch that fixes all errors of B per file ? In some cases there are so many
>> occurrences of a particular error across files it probably does make more
>> sense to create the patches per file.
>>
>> Any thoughts or clarifications on this ?
>
>Ditto. But each case must be evaluated. Some changes (error A and B)
>can be done in one line, so you have to analyze them.
>A real case would be nice for a better exemplification.
>>
>> Cheers:
>> Roger H. Newell
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>
>
>
>-- 
>Regards,
>
>Geyslan G. Bem
>hackingbits.com
>
>_______________________________________________
>Kernelnewbies mailing list
>Kernelnewbies at kernelnewbies.org
>http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
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From mulyadi.santosa at gmail.com  Wed Feb 17 01:10:16 2016
From: mulyadi.santosa at gmail.com (Mulyadi Santosa)
Date: Wed, 17 Feb 2016 13:10:16 +0700
Subject: Process scheduling
In-Reply-To: <CAKfJ7K+ZeZPPLBF9rUzDQgdz66+U_XNWmNgNnDf31B2oOSbj8g@mail.gmail.com>
References: <CAKfJ7KKcBRg1nKQwfAwL0N_bfb-GAa39sVLfFu=ykea1t3yv_A@mail.gmail.com>
	<20160213084904.GB21526@icarus.home.austad.us>
	<CAKfJ7KLkSER2fka7tpYhgGg61FxG-NOO5WjutG0nSCSt4MVheA@mail.gmail.com>
	<CAKfJ7KLrDSLuw-8CQg4jvKdnPRvQqAXHE4Wf+sSZYqJYdzn3dg@mail.gmail.com>
	<CAKfJ7K+ZeZPPLBF9rUzDQgdz66+U_XNWmNgNnDf31B2oOSbj8g@mail.gmail.com>
Message-ID: <CAGdaadYbmNNsZipsCwTdFqfMAZGDSi6Obf-Wcv+n9vtmKU7_ZQ@mail.gmail.com>

On Mon, Feb 15, 2016 at 7:37 PM, Nitin Varyani <varyani.nitin1 at gmail.com>
wrote:

>
>
> On Mon, Feb 15, 2016 at 6:06 PM, Nitin Varyani <varyani.nitin1 at gmail.com>
> wrote:
>
>> Hi
>>         I have studied LInux kernel CFS scheduling algorithm - the
>> vruntime, weights, nice value, etc. I am able to understand the code.
>>  Actually the task given to me is really very huge. I am told to design a
>> distributed process scheduling algorithm. A very simple implementation of
>> it will be sufficient for me. Current distributed OS are patch work over
>> the linux kernels, that is, they are responsible for load balancing through
>> process migration but the scheduling is taken care by the single machine
>> linux kernels. My task is to make the scheduling algorithm itself as
>> distributed. That is a scheduler makes a decision whether to migrate a task
>> or to keep the task in the current system.  I need some design aspects of
>> how to achieve it. Another thing which I want to know is that whether this
>> job is possible for a kernel newbie like me.
>>
>> On Sat, Feb 13, 2016 at 3:12 PM, Nitin Varyani <varyani.nitin1 at gmail.com>
>> wrote:
>>
>>> thanks
>>>
>>> On Sat, Feb 13, 2016 at 2:19 PM, Henrik Austad <henrik at austad.us> wrote:
>>>
>>>> On Sat, Feb 13, 2016 at 11:42:57AM +0530, Nitin Varyani wrote:
>>>> > Hello,
>>>>
>>>> Hi Nitin,
>>>>
>>>> >          I want to understand the flow of code of process scheduler of
>>>> > linux kernel. What I have understood is that
>>>> > The task marks itself as sleeping,
>>>> > puts itself on a wait queue,
>>>> > removes itself from the red-black tree of runnable, and
>>>> > calls schedule() to select a new process to execute.
>>>> >
>>>> > for Waking back up
>>>> > The task is set as runnable,
>>>> > removed from the wait queue,
>>>> > and added back to the red-black tree.
>>>> >
>>>> > Can I get the details of which function does what? in sched/core.c
>>>> and in
>>>> > sched/fair.c
>>>> > I am concerned only with fair scheduler. There are so many functions
>>>> in
>>>> > these two files that I am totally confused.
>>>>
>>>> Then core.c and fair.c is the best bet.
>>>>
>>>> You could also pick up a copy of Linux kernel development (By Love), it
>>>> gives a nice introduction to the overall flow of .. well mostly
>>>> everything.
>>>> :)
>>>>
>>>> In kernel/sched/sched.h you have a struct called 'struct sched_class"
>>>> which
>>>> is a set of function-points. This is used by the core machinery to call
>>>> into scheduling-class specific code. At the bottom of fair.c, you see
>>>> said
>>>> struct being populated.
>>>>
>>>> Also, if you want to see what really happens, try enabling
>>>> function-tracing, but limit it to sched-functions only (and
>>>> sched-events,
>>>> those are also useful to see what triggers things)
>>>>
>>>> mount -t debugfs nodev /sys/kernel/debug
>>>> cd /sys/kernel/debug/tracing
>>>> echo 0 > tracing_on
>>>> echo function > current_tracer
>>>> echo "sched*" > set_ftrace_filter
>>>> echo 1 > events/sched/enable
>>>> echo 1 > tracing_on
>>>> ... wait for a few secs
>>>> echo 0 > tracing_on
>>>>
>>>> cat trace > /tmp/trace.txt
>>>>
>>>> Now, look at trace.txt and correlate it to the scheduler code :)
>>>>
>>>> Good luck!
>>>>
>>>> --
>>>> Henrik Austad
>>>>
>>>
>>>
>>
>
>

Please don't top post :) Use bottom post .

Sounds like what you're going to do is highly similar to openMosix. check
their source code.

Please note that openmosix is patch against 2.4.x linux kernel. When
they're about to made it compatible to 2.6.x, the project stalls. See Linux
IPMI project and see if you can help them out

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

This email has been sent from a virus-free computer protected by Avast.
www.avast.com <https://www.avast.com/sig-email>
<#DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
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From Valdis.Kletnieks at vt.edu  Wed Feb 17 01:10:56 2016
From: Valdis.Kletnieks at vt.edu (Valdis.Kletnieks at vt.edu)
Date: Wed, 17 Feb 2016 01:10:56 -0500
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <CAKfJ7KKxoh3a-Yw4c+5Kf42gWxMiGam3JJ3u=HyhJ=uA7uMdoQ@mail.gmail.com>
References: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>
	<20160215165231.GD21526@icarus.home.austad.us>
	<CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>
	<42173.1455599614@turing-police.cc.vt.edu>
	<20160216094252.194c7907@BR9TG4T3.de.ibm.com>
	<124507.1455640511@turing-police.cc.vt.edu>
	<CAKfJ7KKxoh3a-Yw4c+5Kf42gWxMiGam3JJ3u=HyhJ=uA7uMdoQ@mail.gmail.com>
Message-ID: <21502.1455689456@turing-police.cc.vt.edu>

On Wed, 17 Feb 2016 10:21:35 +0530, Nitin Varyani said:

> Actually it is a master's thesis research project as of now. I am ready to
> boil down to the most basic implementation of distributed linux kernel.
> Assume there is no network connection and no open files. We can drop even
> more assumptions if it becomes complicated. Once this basic implementation
> is successful, we can go ahead with a more complicated version. The next
> task is to integrate the migration code in the linux kernel. What is the
> most easy way of implementing it.

If you get it to where you can migrate a process on command controlled by
a userspace process, the scheduler part will be trivial.

And note that the choice of which process to migrate where is sufficiently
"policy" that it belongs in userspace - see how cgroups and containers are
kernel mechanisms that are controlled by userspace.  You want to follow that
model if you intend for this to be upstreamed rather than just another dead
master's thesis.
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From Valdis.Kletnieks at vt.edu  Wed Feb 17 01:16:11 2016
From: Valdis.Kletnieks at vt.edu (Valdis.Kletnieks at vt.edu)
Date: Wed, 17 Feb 2016 01:16:11 -0500
Subject: Patch Series
In-Reply-To: <65fa18ad.43fb.152ed99983e.Coremail.yuzibode@126.com>
References: <CAEE9rjahhbnLxFAu0nnb2AOQzo8D0J7_tHS3xPuo56hrJx75FQ@mail.gmail.com>
	<CAGG-pUSYP=MyDkz2P7R=vdr8X4--==q_qfH970gj=YXz+bCFNQ@mail.gmail.com>
	<65fa18ad.43fb.152ed99983e.Coremail.yuzibode@126.com>
Message-ID: <21927.1455689771@turing-police.cc.vt.edu>


>>> My question is, is it OK to fix all occurrences of error A across the files
>> inside drivers/staging/wilc1000 as one patch and all occurrences of error B
>> across all files inside drivers/staging/wilc1000 as a second patch?

Most maintainers would be perfectly OK with that.  And I'm pretty sure
that Greg KH (maintainer of drivers/staging) would accept that sort of
patch series.  If he isn't, I'm sure he'll correct me. :)
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From mfidelman at meetinghouse.net  Wed Feb 17 01:37:06 2016
From: mfidelman at meetinghouse.net (Miles Fidelman)
Date: Wed, 17 Feb 2016 01:37:06 -0500
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <21502.1455689456@turing-police.cc.vt.edu>
References: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>
	<20160215165231.GD21526@icarus.home.austad.us>
	<CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>
	<42173.1455599614@turing-police.cc.vt.edu>
	<20160216094252.194c7907@BR9TG4T3.de.ibm.com>
	<124507.1455640511@turing-police.cc.vt.edu>
	<CAKfJ7KKxoh3a-Yw4c+5Kf42gWxMiGam3JJ3u=HyhJ=uA7uMdoQ@mail.gmail.com>
	<21502.1455689456@turing-police.cc.vt.edu>
Message-ID: <56C41512.4000100@meetinghouse.net>



On 2/17/16 1:10 AM, Valdis.Kletnieks at vt.edu wrote:
> On Wed, 17 Feb 2016 10:21:35 +0530, Nitin Varyani said:
>
>> Actually it is a master's thesis research project as of now. I am ready to
>> boil down to the most basic implementation of distributed linux kernel.
>> Assume there is no network connection and no open files. We can drop even
>> more assumptions if it becomes complicated. Once this basic implementation
>> is successful, we can go ahead with a more complicated version. The next
>> task is to integrate the migration code in the linux kernel. What is the
>> most easy way of implementing it.
> If you get it to where you can migrate a process on command controlled by
> a userspace process, the scheduler part will be trivial.
>

If you want some ideas about distributed process scheduling, you might 
want to explore how Erlang's run-time works - it's all about massive 
concurrency and scheduling processes (well, really light-weight 
processes) across multiple cores.  If you google "distributed process 
scheduling erlang" you'll also find some work about process scheduling 
across clusters, particularly for gaming environments.

How much might be applicable in a linux kernel environment is unclear - 
but, then, it's your research project.

Miles Fidelman


In theory, there is no difference between theory and practice.
In practice, there is.  .... Yogi Berra



From varyani.nitin1 at gmail.com  Wed Feb 17 02:18:33 2016
From: varyani.nitin1 at gmail.com (Nitin Varyani)
Date: Wed, 17 Feb 2016 12:48:33 +0530
Subject: Process scheduling
In-Reply-To: <CAGdaadYbmNNsZipsCwTdFqfMAZGDSi6Obf-Wcv+n9vtmKU7_ZQ@mail.gmail.com>
References: <CAKfJ7KKcBRg1nKQwfAwL0N_bfb-GAa39sVLfFu=ykea1t3yv_A@mail.gmail.com>
	<20160213084904.GB21526@icarus.home.austad.us>
	<CAKfJ7KLkSER2fka7tpYhgGg61FxG-NOO5WjutG0nSCSt4MVheA@mail.gmail.com>
	<CAKfJ7KLrDSLuw-8CQg4jvKdnPRvQqAXHE4Wf+sSZYqJYdzn3dg@mail.gmail.com>
	<CAKfJ7K+ZeZPPLBF9rUzDQgdz66+U_XNWmNgNnDf31B2oOSbj8g@mail.gmail.com>
	<CAGdaadYbmNNsZipsCwTdFqfMAZGDSi6Obf-Wcv+n9vtmKU7_ZQ@mail.gmail.com>
Message-ID: <CAKfJ7KJs+=RdjcPvJgPQetY7m-zhATvMW=fr3DHhFaj-uZaTqg@mail.gmail.com>

It is similar to openMosix but still quite different. Open Mosix is built
on the top of existing linux kernels. The scheduling is taken care by the
existing linux kernels. Open Mosix is responsible for workload
distribution. This project is first of its kind.

On Wed, Feb 17, 2016 at 11:40 AM, Mulyadi Santosa <mulyadi.santosa at gmail.com
> wrote:

>
>
> On Mon, Feb 15, 2016 at 7:37 PM, Nitin Varyani <varyani.nitin1 at gmail.com>
> wrote:
>
>>
>>
>> On Mon, Feb 15, 2016 at 6:06 PM, Nitin Varyani <varyani.nitin1 at gmail.com>
>> wrote:
>>
>>> Hi
>>>         I have studied LInux kernel CFS scheduling algorithm - the
>>> vruntime, weights, nice value, etc. I am able to understand the code.
>>>  Actually the task given to me is really very huge. I am told to design
>>> a distributed process scheduling algorithm. A very simple implementation of
>>> it will be sufficient for me. Current distributed OS are patch work over
>>> the linux kernels, that is, they are responsible for load balancing through
>>> process migration but the scheduling is taken care by the single machine
>>> linux kernels. My task is to make the scheduling algorithm itself as
>>> distributed. That is a scheduler makes a decision whether to migrate a task
>>> or to keep the task in the current system.  I need some design aspects of
>>> how to achieve it. Another thing which I want to know is that whether this
>>> job is possible for a kernel newbie like me.
>>>
>>> On Sat, Feb 13, 2016 at 3:12 PM, Nitin Varyani <varyani.nitin1 at gmail.com
>>> > wrote:
>>>
>>>> thanks
>>>>
>>>> On Sat, Feb 13, 2016 at 2:19 PM, Henrik Austad <henrik at austad.us>
>>>> wrote:
>>>>
>>>>> On Sat, Feb 13, 2016 at 11:42:57AM +0530, Nitin Varyani wrote:
>>>>> > Hello,
>>>>>
>>>>> Hi Nitin,
>>>>>
>>>>> >          I want to understand the flow of code of process scheduler
>>>>> of
>>>>> > linux kernel. What I have understood is that
>>>>> > The task marks itself as sleeping,
>>>>> > puts itself on a wait queue,
>>>>> > removes itself from the red-black tree of runnable, and
>>>>> > calls schedule() to select a new process to execute.
>>>>> >
>>>>> > for Waking back up
>>>>> > The task is set as runnable,
>>>>> > removed from the wait queue,
>>>>> > and added back to the red-black tree.
>>>>> >
>>>>> > Can I get the details of which function does what? in sched/core.c
>>>>> and in
>>>>> > sched/fair.c
>>>>> > I am concerned only with fair scheduler. There are so many functions
>>>>> in
>>>>> > these two files that I am totally confused.
>>>>>
>>>>> Then core.c and fair.c is the best bet.
>>>>>
>>>>> You could also pick up a copy of Linux kernel development (By Love), it
>>>>> gives a nice introduction to the overall flow of .. well mostly
>>>>> everything.
>>>>> :)
>>>>>
>>>>> In kernel/sched/sched.h you have a struct called 'struct sched_class"
>>>>> which
>>>>> is a set of function-points. This is used by the core machinery to call
>>>>> into scheduling-class specific code. At the bottom of fair.c, you see
>>>>> said
>>>>> struct being populated.
>>>>>
>>>>> Also, if you want to see what really happens, try enabling
>>>>> function-tracing, but limit it to sched-functions only (and
>>>>> sched-events,
>>>>> those are also useful to see what triggers things)
>>>>>
>>>>> mount -t debugfs nodev /sys/kernel/debug
>>>>> cd /sys/kernel/debug/tracing
>>>>> echo 0 > tracing_on
>>>>> echo function > current_tracer
>>>>> echo "sched*" > set_ftrace_filter
>>>>> echo 1 > events/sched/enable
>>>>> echo 1 > tracing_on
>>>>> ... wait for a few secs
>>>>> echo 0 > tracing_on
>>>>>
>>>>> cat trace > /tmp/trace.txt
>>>>>
>>>>> Now, look at trace.txt and correlate it to the scheduler code :)
>>>>>
>>>>> Good luck!
>>>>>
>>>>> --
>>>>> Henrik Austad
>>>>>
>>>>
>>>>
>>>
>>
>>
>
> Please don't top post :) Use bottom post .
>
> Sounds like what you're going to do is highly similar to openMosix. check
> their source code.
>
> Please note that openmosix is patch against 2.4.x linux kernel. When
> they're about to made it compatible to 2.6.x, the project stalls. See Linux
> IPMI project and see if you can help them out
>
> --
> regards,
>
> Mulyadi Santosa
> Freelance Linux trainer and consultant
>
> blog: the-hydra.blogspot.com
> training: mulyaditraining.blogspot.com
>
> This email has been sent from a virus-free computer protected by Avast.
> www.avast.com <https://www.avast.com/sig-email>
> <#1657133857_DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>
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From mudongliangabcd at gmail.com  Wed Feb 17 02:52:45 2016
From: mudongliangabcd at gmail.com (=?UTF-8?B?5oWV5Yas5Lqu?=)
Date: Wed, 17 Feb 2016 15:52:45 +0800
Subject: Help about Ctrl-Z and Ctrl-Y(urgent)
Message-ID: <CAD-N9QVC==T2-+dKDU=EWMeNh9SCu=fKbweYegye9NCLHX=hKg@mail.gmail.com>

Hi everyone,
    Unix systems support a large number of special characters that
receive special processing by the OS. One such character is the
?suspend? character (ctrl-Z by default), that causes a SIGTSTP signal
to be sent to the application process. The default action for the
signal is to suspend execution of the process. The system responds to
the suspend character (by sending the signal) as soon as possible
after it is typed in. In older Unix systems there was another special
character known as the ?delayed suspend? character (ctrl-Y by default)
that had the same effect as the suspend character, except that the
signal is sent when the application process consumes the character,
rather than right away. (That this feature is no longer supported is
perhaps some indication of how useful it was ...) The suspend and the
delayed-suspend characters have the effect, when they are processed,
of deleting all characters currently waiting to be read by the user
application that arrived before them. Explain, how both special
characters are implemented?

-- 
My best regards to you.

     No System Is Safe!
     mudongliang


From varyani.nitin1 at gmail.com  Wed Feb 17 05:35:17 2016
From: varyani.nitin1 at gmail.com (Nitin Varyani)
Date: Wed, 17 Feb 2016 16:05:17 +0530
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <21502.1455689456@turing-police.cc.vt.edu>
References: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>
	<20160215165231.GD21526@icarus.home.austad.us>
	<CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>
	<42173.1455599614@turing-police.cc.vt.edu>
	<20160216094252.194c7907@BR9TG4T3.de.ibm.com>
	<124507.1455640511@turing-police.cc.vt.edu>
	<CAKfJ7KKxoh3a-Yw4c+5Kf42gWxMiGam3JJ3u=HyhJ=uA7uMdoQ@mail.gmail.com>
	<21502.1455689456@turing-police.cc.vt.edu>
Message-ID: <CAKfJ7K+1XjdSnXfUQD4Hp+oaGVzhvw_7w4A2SK9d8DgJ-t1-GA@mail.gmail.com>

Having got some clarity of what I have to do, I want to now proceed
for a step by step development. What all I know about linux kernels is
a theoretical understanding of its various components (from the book
of Robert Love) but as far as practical is concerned, I know the
following things:
1) Linking modules dynamically to kernel at run time ( outside source
tree and inside source tree)
2) Adding system calls

Rather than trying to go blind folded in getting practical experience
of linux programming, I want to gain experience only in relation to my
task of creating a distributed process scheduler. What all things
should I try to work with to understand the kernel CFS scheduler well?
Please provide sufficient literature for the practical work.
Also what is the best place to learn about implementing linux containers?


On Wed, Feb 17, 2016 at 11:40 AM,  <Valdis.Kletnieks at vt.edu> wrote:
> On Wed, 17 Feb 2016 10:21:35 +0530, Nitin Varyani said:
>
>> Actually it is a master's thesis research project as of now. I am ready to
>> boil down to the most basic implementation of distributed linux kernel.
>> Assume there is no network connection and no open files. We can drop even
>> more assumptions if it becomes complicated. Once this basic implementation
>> is successful, we can go ahead with a more complicated version. The next
>> task is to integrate the migration code in the linux kernel. What is the
>> most easy way of implementing it.
>
> If you get it to where you can migrate a process on command controlled by
> a userspace process, the scheduler part will be trivial.
>
> And note that the choice of which process to migrate where is sufficiently
> "policy" that it belongs in userspace - see how cgroups and containers are
> kernel mechanisms that are controlled by userspace.  You want to follow that
> model if you intend for this to be upstreamed rather than just another dead
> master's thesis.


From greg at kroah.com  Wed Feb 17 10:32:42 2016
From: greg at kroah.com (Greg KH)
Date: Wed, 17 Feb 2016 07:32:42 -0800
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <CAKfJ7K+1XjdSnXfUQD4Hp+oaGVzhvw_7w4A2SK9d8DgJ-t1-GA@mail.gmail.com>
References: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>
	<20160215165231.GD21526@icarus.home.austad.us>
	<CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>
	<42173.1455599614@turing-police.cc.vt.edu>
	<20160216094252.194c7907@BR9TG4T3.de.ibm.com>
	<124507.1455640511@turing-police.cc.vt.edu>
	<CAKfJ7KKxoh3a-Yw4c+5Kf42gWxMiGam3JJ3u=HyhJ=uA7uMdoQ@mail.gmail.com>
	<21502.1455689456@turing-police.cc.vt.edu>
	<CAKfJ7K+1XjdSnXfUQD4Hp+oaGVzhvw_7w4A2SK9d8DgJ-t1-GA@mail.gmail.com>
Message-ID: <20160217153242.GA15814@kroah.com>

On Wed, Feb 17, 2016 at 04:05:17PM +0530, Nitin Varyani wrote:
> Rather than trying to go blind folded in getting practical experience
> of linux programming, I want to gain experience only in relation to my
> task of creating a distributed process scheduler. What all things
> should I try to work with to understand the kernel CFS scheduler well?
> Please provide sufficient literature for the practical work.
> Also what is the best place to learn about implementing linux containers?

Why are you asking other people to do your research work for you?
That's pretty rude, does your professor know this is what you are doing?

greg k-h


From greg at kroah.com  Wed Feb 17 11:22:51 2016
From: greg at kroah.com (Greg KH)
Date: Wed, 17 Feb 2016 08:22:51 -0800
Subject: Help about Ctrl-Z and Ctrl-Y(urgent)
In-Reply-To: <CAD-N9QVC==T2-+dKDU=EWMeNh9SCu=fKbweYegye9NCLHX=hKg@mail.gmail.com>
References: <CAD-N9QVC==T2-+dKDU=EWMeNh9SCu=fKbweYegye9NCLHX=hKg@mail.gmail.com>
Message-ID: <20160217162251.GA21722@kroah.com>

On Wed, Feb 17, 2016 at 03:52:45PM +0800, ??? wrote:
> Hi everyone,
>     Unix systems support a large number of special characters that
> receive special processing by the OS. One such character is the
> ?suspend? character (ctrl-Z by default), that causes a SIGTSTP signal
> to be sent to the application process. The default action for the
> signal is to suspend execution of the process. The system responds to
> the suspend character (by sending the signal) as soon as possible
> after it is typed in. In older Unix systems there was another special
> character known as the ?delayed suspend? character (ctrl-Y by default)
> that had the same effect as the suspend character, except that the
> signal is sent when the application process consumes the character,
> rather than right away. (That this feature is no longer supported is
> perhaps some indication of how useful it was ...) The suspend and the
> delayed-suspend characters have the effect, when they are processed,
> of deleting all characters currently waiting to be read by the user
> application that arrived before them. Explain, how both special
> characters are implemented?

That sounds like a homework question, why exactly do you need/want to
know this, and what have you done already to try to figure it out
yourself?

greg k-h


From greg at kroah.com  Wed Feb 17 11:23:41 2016
From: greg at kroah.com (Greg KH)
Date: Wed, 17 Feb 2016 08:23:41 -0800
Subject: Process scheduling
In-Reply-To: <CAKfJ7KJs+=RdjcPvJgPQetY7m-zhATvMW=fr3DHhFaj-uZaTqg@mail.gmail.com>
References: <CAKfJ7KKcBRg1nKQwfAwL0N_bfb-GAa39sVLfFu=ykea1t3yv_A@mail.gmail.com>
	<20160213084904.GB21526@icarus.home.austad.us>
	<CAKfJ7KLkSER2fka7tpYhgGg61FxG-NOO5WjutG0nSCSt4MVheA@mail.gmail.com>
	<CAKfJ7KLrDSLuw-8CQg4jvKdnPRvQqAXHE4Wf+sSZYqJYdzn3dg@mail.gmail.com>
	<CAKfJ7K+ZeZPPLBF9rUzDQgdz66+U_XNWmNgNnDf31B2oOSbj8g@mail.gmail.com>
	<CAGdaadYbmNNsZipsCwTdFqfMAZGDSi6Obf-Wcv+n9vtmKU7_ZQ@mail.gmail.com>
	<CAKfJ7KJs+=RdjcPvJgPQetY7m-zhATvMW=fr3DHhFaj-uZaTqg@mail.gmail.com>
Message-ID: <20160217162341.GB21722@kroah.com>

On Wed, Feb 17, 2016 at 12:48:33PM +0530, Nitin Varyani wrote:
> It is similar to openMosix but still quite different. Open Mosix is built on
> the top of existing linux kernels. The scheduling is taken care by the existing
> linux kernels. Open Mosix is responsible for workload distribution. This
> project is first of its kind.

No, it's not, it's been tried before, I suggest doing a bit more
research before making statements like that.

good luck,

greg k-h


From nayobix at nayobix.org  Wed Feb 17 16:13:11 2016
From: nayobix at nayobix.org (Boyan Vladinov)
Date: Wed, 17 Feb 2016 23:13:11 +0200
Subject: Process scheduling
In-Reply-To: <20160217162341.GB21722@kroah.com>
References: <CAKfJ7KKcBRg1nKQwfAwL0N_bfb-GAa39sVLfFu=ykea1t3yv_A@mail.gmail.com>
	<20160213084904.GB21526@icarus.home.austad.us>
	<CAKfJ7KLkSER2fka7tpYhgGg61FxG-NOO5WjutG0nSCSt4MVheA@mail.gmail.com>
	<CAKfJ7KLrDSLuw-8CQg4jvKdnPRvQqAXHE4Wf+sSZYqJYdzn3dg@mail.gmail.com>
	<CAKfJ7K+ZeZPPLBF9rUzDQgdz66+U_XNWmNgNnDf31B2oOSbj8g@mail.gmail.com>
	<CAGdaadYbmNNsZipsCwTdFqfMAZGDSi6Obf-Wcv+n9vtmKU7_ZQ@mail.gmail.com>
	<CAKfJ7KJs+=RdjcPvJgPQetY7m-zhATvMW=fr3DHhFaj-uZaTqg@mail.gmail.com>
	<20160217162341.GB21722@kroah.com>
Message-ID: <56C4E267.3010509@nayobix.org>

Check here:

https://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt
and
http://www.ibm.com/developerworks/library/l-completely-fair-scheduler/

Regards,
Boyan Vladinov

On 17.02.2016 18:23, Greg KH wrote:
> On Wed, Feb 17, 2016 at 12:48:33PM +0530, Nitin Varyani wrote:
>> It is similar to openMosix but still quite different. Open Mosix is built on
>> the top of existing linux kernels. The scheduling is taken care by the existing
>> linux kernels. Open Mosix is responsible for workload distribution. This
>> project is first of its kind.
> No, it's not, it's been tried before, I suggest doing a bit more
> research before making statements like that.
>
> good luck,
>
> greg k-h
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies



From nayobix at nayobix.org  Wed Feb 17 16:11:38 2016
From: nayobix at nayobix.org (Boyan Vladinov)
Date: Wed, 17 Feb 2016 23:11:38 +0200
Subject: Process scheduling
In-Reply-To: <20160217162341.GB21722@kroah.com>
References: <CAKfJ7KKcBRg1nKQwfAwL0N_bfb-GAa39sVLfFu=ykea1t3yv_A@mail.gmail.com>
	<20160213084904.GB21526@icarus.home.austad.us>
	<CAKfJ7KLkSER2fka7tpYhgGg61FxG-NOO5WjutG0nSCSt4MVheA@mail.gmail.com>
	<CAKfJ7KLrDSLuw-8CQg4jvKdnPRvQqAXHE4Wf+sSZYqJYdzn3dg@mail.gmail.com>
	<CAKfJ7K+ZeZPPLBF9rUzDQgdz66+U_XNWmNgNnDf31B2oOSbj8g@mail.gmail.com>
	<CAGdaadYbmNNsZipsCwTdFqfMAZGDSi6Obf-Wcv+n9vtmKU7_ZQ@mail.gmail.com>
	<CAKfJ7KJs+=RdjcPvJgPQetY7m-zhATvMW=fr3DHhFaj-uZaTqg@mail.gmail.com>
	<20160217162341.GB21722@kroah.com>
Message-ID: <56C4E20A.4090601@nayobix.org>

Check here:

https://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt
and
http://www.ibm.com/developerworks/library/l-completely-fair-scheduler/

Regards,
Boyan Vladinov

On 17.02.2016 18:23, Greg KH wrote:
> On Wed, Feb 17, 2016 at 12:48:33PM +0530, Nitin Varyani wrote:
>> It is similar to openMosix but still quite different. Open Mosix is built on
>> the top of existing linux kernels. The scheduling is taken care by the existing
>> linux kernels. Open Mosix is responsible for workload distribution. This
>> project is first of its kind.
> No, it's not, it's been tried before, I suggest doing a bit more
> research before making statements like that.
>
> good luck,
>
> greg k-h
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies



From varyani.nitin1 at gmail.com  Wed Feb 17 23:35:40 2016
From: varyani.nitin1 at gmail.com (Nitin Varyani)
Date: Thu, 18 Feb 2016 10:05:40 +0530
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <20160217153242.GA15814@kroah.com>
References: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>
	<20160215165231.GD21526@icarus.home.austad.us>
	<CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>
	<42173.1455599614@turing-police.cc.vt.edu>
	<20160216094252.194c7907@BR9TG4T3.de.ibm.com>
	<124507.1455640511@turing-police.cc.vt.edu>
	<CAKfJ7KKxoh3a-Yw4c+5Kf42gWxMiGam3JJ3u=HyhJ=uA7uMdoQ@mail.gmail.com>
	<21502.1455689456@turing-police.cc.vt.edu>
	<CAKfJ7K+1XjdSnXfUQD4Hp+oaGVzhvw_7w4A2SK9d8DgJ-t1-GA@mail.gmail.com>
	<20160217153242.GA15814@kroah.com>
Message-ID: <CAKfJ7KJNiiV=xgdjDLm68nVORhg_CMdqeTVaEGor1K3X0jk69A@mail.gmail.com>

@ Greg: Since I am very new to the field, with the huge task in hand
and a short time span of 3 months given for this project, I am looking
for specific directions from the linux experts to work on. As far as
efforts are concerned, I am taking out hours together to research into
this area. I do not mind telling this to my professor.  Still, I am
always looking for improvement. I will try to put more endeavor and
seek as less help as possible. I hope you will not mind my reply.
Thanks.

On Wed, Feb 17, 2016 at 9:02 PM, Greg KH <greg at kroah.com> wrote:
> On Wed, Feb 17, 2016 at 04:05:17PM +0530, Nitin Varyani wrote:
>> Rather than trying to go blind folded in getting practical experience
>> of linux programming, I want to gain experience only in relation to my
>> task of creating a distributed process scheduler. What all things
>> should I try to work with to understand the kernel CFS scheduler well?
>> Please provide sufficient literature for the practical work.
>> Also what is the best place to learn about implementing linux containers?
>
> Why are you asking other people to do your research work for you?
> That's pretty rude, does your professor know this is what you are doing?
>
> greg k-h


From mulyadi.santosa at gmail.com  Thu Feb 18 04:31:53 2016
From: mulyadi.santosa at gmail.com (Mulyadi Santosa)
Date: Thu, 18 Feb 2016 16:31:53 +0700
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <CAKfJ7KJNiiV=xgdjDLm68nVORhg_CMdqeTVaEGor1K3X0jk69A@mail.gmail.com>
References: <CAKfJ7KLaNMabXoVdBTHC2hATkbgesmSi4uTPwGdCdKqMzJCPKg@mail.gmail.com>
	<20160215165231.GD21526@icarus.home.austad.us>
	<CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>
	<42173.1455599614@turing-police.cc.vt.edu>
	<20160216094252.194c7907@BR9TG4T3.de.ibm.com>
	<124507.1455640511@turing-police.cc.vt.edu>
	<CAKfJ7KKxoh3a-Yw4c+5Kf42gWxMiGam3JJ3u=HyhJ=uA7uMdoQ@mail.gmail.com>
	<21502.1455689456@turing-police.cc.vt.edu>
	<CAKfJ7K+1XjdSnXfUQD4Hp+oaGVzhvw_7w4A2SK9d8DgJ-t1-GA@mail.gmail.com>
	<20160217153242.GA15814@kroah.com>
	<CAKfJ7KJNiiV=xgdjDLm68nVORhg_CMdqeTVaEGor1K3X0jk69A@mail.gmail.com>
Message-ID: <CAGdaadaZ9SJuOnBcMg2V8byidGhc5CpCpxxsgyoRWb3o86eYfw@mail.gmail.com>

On Thu, Feb 18, 2016 at 11:35 AM, Nitin Varyani <varyani.nitin1 at gmail.com>
wrote:

> @ Greg: Since I am very new to the field, with the huge task in hand
> and a short time span of 3 months given for this project, I am looking
> for specific directions from the linux experts to work on. As far as
> efforts are concerned, I am taking out hours together to research into
> this area. I do not mind telling this to my professor.  Still, I am
> always looking for improvement. I will try to put more endeavor and
> seek as less help as possible. I hope you will not mind my reply.
> Thanks.
>
> On Wed, Feb 17, 2016 at 9:02 PM, Greg KH <greg at kroah.com> wrote:
> > On Wed, Feb 17, 2016 at 04:05:17PM +0530, Nitin Varyani wrote:
> >> Rather than trying to go blind folded in getting practical experience
> >> of linux programming, I want to gain experience only in relation to my
> >> task of creating a distributed process scheduler. What all things
> >> should I try to work with to understand the kernel CFS scheduler well?
> >> Please provide sufficient literature for the practical work.
> >> Also what is the best place to learn about implementing linux
> containers?
> >
> > Why are you asking other people to do your research work for you?
> > That's pretty rude, does your professor know this is what you are doing?
> >
> > greg k-h
>
>

Dear Nitin

Again, please don't top post :) That's considered rude too, at least here :)

I can't speak on behalf of Greg, but I guess the basic idea of why people
gather in this mailing list is to share ideas and discuss, but not giving
very specific guidance. If that's the goal, this list would be named
"kernel mentoring", don't you agree? :)

So, if we follow this "discussion area" rule, I can give you ideas:
- maybe your scope of work is too wide. Try to be more specific. 3 months
time span is very short compared to what you're going to do (IIUC). As
other already pointed, maybe you can piggy back on Erlang project and
enhance their work instead?

- do you have solid background of kernel programming, especially related to
scheduler? if not, try to get a grasp quickly using code navigator e.g
cscope or lxr.linux.no and play around with the code first. It might give
direct experience on how code works and at the same time how kernel build
mechanism work

Hope it helps....

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com
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From joseph.bisch at gmail.com  Thu Feb 18 06:25:46 2016
From: joseph.bisch at gmail.com (Joseph Bisch)
Date: Thu, 18 Feb 2016 06:25:46 -0500
Subject: Question regarding upstreaming patches written by multiple people and
	checkpatch
Message-ID: <CAO+PtjuU1o6GF1w34j17jrDRdOWcf4TvmCoLzf4+6gVeToo2XA@mail.gmail.com>

Hi,

I am trying to upstream a patch set that wasn't written by me. The
original patch has a lot of warnings and errors reported by
checkpatch. Someone else corrected some of those with another patch
and I added on a third patch correcting the rest of the warnings and
errors that I thought were appropriate to fix.

When checkpatch is run on the file that the patches affect, the output
looks okay to me, but when I run checkpatch on the patches themselves,
the patches still have the same errors and warnings, because I made my
changes in a separate patch.

So is it okay to have checkpatch errors/warnings for individual
patches as long as the patch series as a whole is reasonably
checkpatch clean or should I be amending my changes to the original
commit and squashing the other cleanup patch into the first patch, so
that I am left with one patch that passes checkpatch?

If I should be squashing the patches into a single patch, how do I
handle the signed-off-by lines as each of the three patches is
currently signed off by the respective author of the patch? Obviously
I can sign off on the squashed patch for myself. Do I just send it to
the mailing list with just my sign off and CC the authors, so that
they can sign off on it? From what I've been told, it sounds like
CC'ing the authors and having them reply with their sign off is the
appropriate way to handle this, but I want to make sure before I start
mailing out patches, and this isn't something that I have been able to
find an answer to.

Cheers,
Joseph


From mike at flyn.org  Thu Feb 18 13:05:08 2016
From: mike at flyn.org (W. Michael Petullo)
Date: Thu, 18 Feb 2016 13:05:08 -0500
Subject: Walk list of processes attached to a shared page
Message-ID: <20160218180508.GA32559@imp.flyn.org>

Is it possible to walk the processes already attached to a shared page
in an implementation of security_shm_shmat()?

I have a function:

	static int my_shm_shmat(struct shmid_kernel *shp, char __user *shmaddr,
				int shmflag)

and I would like to find the processes already attached.

It seems like rmap_walk() would help, but I cannot figure out how to
get an appropriate struct page out of a struct shmid_kernel or unmapped
address (i.e., shmaddr above).

-- 
Mike

:wq


From greg at kroah.com  Thu Feb 18 13:46:00 2016
From: greg at kroah.com (Greg KH)
Date: Thu, 18 Feb 2016 10:46:00 -0800
Subject: Question regarding upstreaming patches written by multiple
	people and checkpatch
In-Reply-To: <CAO+PtjuU1o6GF1w34j17jrDRdOWcf4TvmCoLzf4+6gVeToo2XA@mail.gmail.com>
References: <CAO+PtjuU1o6GF1w34j17jrDRdOWcf4TvmCoLzf4+6gVeToo2XA@mail.gmail.com>
Message-ID: <20160218184600.GA10115@kroah.com>

On Thu, Feb 18, 2016 at 06:25:46AM -0500, Joseph Bisch wrote:
> Hi,
> 
> I am trying to upstream a patch set that wasn't written by me. The
> original patch has a lot of warnings and errors reported by
> checkpatch. Someone else corrected some of those with another patch
> and I added on a third patch correcting the rest of the warnings and
> errors that I thought were appropriate to fix.
> 
> When checkpatch is run on the file that the patches affect, the output
> looks okay to me, but when I run checkpatch on the patches themselves,
> the patches still have the same errors and warnings, because I made my
> changes in a separate patch.
> 
> So is it okay to have checkpatch errors/warnings for individual
> patches as long as the patch series as a whole is reasonably
> checkpatch clean

Usually, yes, this is fine.

But it can depend on the subsystem / area of the kernel you are
submitting this for, what type of code is this?  What maintainer(s) are
you going to have to send the patches to?

> or should I be amending my changes to the original
> commit and squashing the other cleanup patch into the first patch, so
> that I am left with one patch that passes checkpatch?

I would preserve original authorship and signed-off-by as much as
possible.

Hope this helps,

greg k-h


From joseph.bisch at gmail.com  Thu Feb 18 15:21:44 2016
From: joseph.bisch at gmail.com (Joseph Bisch)
Date: Thu, 18 Feb 2016 15:21:44 -0500
Subject: Question regarding upstreaming patches written by multiple people
	and checkpatch
In-Reply-To: <20160218184600.GA10115@kroah.com>
References: <CAO+PtjuU1o6GF1w34j17jrDRdOWcf4TvmCoLzf4+6gVeToo2XA@mail.gmail.com>
	<20160218184600.GA10115@kroah.com>
Message-ID: <CAO+PtjtSGBhMza05o26XE4fM4zswVjFqEHUOC1QfjyJhXJngLQ@mail.gmail.com>

On Thu, Feb 18, 2016 at 1:46 PM, Greg KH <greg at kroah.com> wrote:
> On Thu, Feb 18, 2016 at 06:25:46AM -0500, Joseph Bisch wrote:
>> Hi,
>>
>> I am trying to upstream a patch set that wasn't written by me. The
>> original patch has a lot of warnings and errors reported by
>> checkpatch. Someone else corrected some of those with another patch
>> and I added on a third patch correcting the rest of the warnings and
>> errors that I thought were appropriate to fix.
>>
>> When checkpatch is run on the file that the patches affect, the output
>> looks okay to me, but when I run checkpatch on the patches themselves,
>> the patches still have the same errors and warnings, because I made my
>> changes in a separate patch.
>>
>> So is it okay to have checkpatch errors/warnings for individual
>> patches as long as the patch series as a whole is reasonably
>> checkpatch clean
>
> Usually, yes, this is fine.
>
> But it can depend on the subsystem / area of the kernel you are
> submitting this for, what type of code is this?  What maintainer(s) are
> you going to have to send the patches to?

The patch set[0] (link doesn't include my patch) is a driver for the
quadrature encoder pulse decoder unit on the AM33xx series SoC.
According to get_maintainer.pl, I am sending the patches to OMAP
DEVICE TREE SUPPORT maintainers, OPEN FIRMWARE AND FLATTENED DEVICE
TREE BINDINGS maintainers, the ARM PORT maintainer, you and the other
CHAR and MISC DRIVERS supporter, and the mailing lists.

>> or should I be amending my changes to the original
>> commit and squashing the other cleanup patch into the first patch, so
>> that I am left with one patch that passes checkpatch?
>
> I would preserve original authorship and signed-off-by as much as
> possible.

Okay. The author of the second patch said I should squash it into the
first (because it was just an upstream kernel interface change), so I
put the commit message from the second patch (because it was just one
line) in brackets between the two sign off lines as I've seen
maintainers do when they need to make a last minute change before
accepting a patch. Should I have done it that way? Or would you still
keep them as separate patches?

> Hope this helps,

Yes it does. Thanks!

[0] - https://github.com/RobertCNelson/linux-dev/tree/master/patches/beaglebone/eqep

Joseph


From mudongliangabcd at gmail.com  Thu Feb 18 23:59:15 2016
From: mudongliangabcd at gmail.com (=?UTF-8?B?5oWV5Yas5Lqu?=)
Date: Fri, 19 Feb 2016 12:59:15 +0800
Subject: Help about Ctrl-Z and Ctrl-Y(urgent)
In-Reply-To: <20160217162251.GA21722@kroah.com>
References: <CAD-N9QVC==T2-+dKDU=EWMeNh9SCu=fKbweYegye9NCLHX=hKg@mail.gmail.com>
	<20160217162251.GA21722@kroah.com>
Message-ID: <CAD-N9QUTF_L=AxaC3tEdOJCANSfT6Oa7+OJodaXY5L-aBFBk9w@mail.gmail.com>

Hi,
    This question is provided by one of my friends. He only provided
me little information. I didn't know much detail in this part.
    I have searched the relative information on the network. But with
no good result. So I asked for help in mailing list.

2016-02-18 0:22 GMT+08:00 Greg KH <greg at kroah.com>:
> On Wed, Feb 17, 2016 at 03:52:45PM +0800, ??? wrote:
>> Hi everyone,
>>     Unix systems support a large number of special characters that
>> receive special processing by the OS. One such character is the
>> ?suspend? character (ctrl-Z by default), that causes a SIGTSTP signal
>> to be sent to the application process. The default action for the
>> signal is to suspend execution of the process. The system responds to
>> the suspend character (by sending the signal) as soon as possible
>> after it is typed in. In older Unix systems there was another special
>> character known as the ?delayed suspend? character (ctrl-Y by default)
>> that had the same effect as the suspend character, except that the
>> signal is sent when the application process consumes the character,
>> rather than right away. (That this feature is no longer supported is
>> perhaps some indication of how useful it was ...) The suspend and the
>> delayed-suspend characters have the effect, when they are processed,
>> of deleting all characters currently waiting to be read by the user
>> application that arrived before them. Explain, how both special
>> characters are implemented?
>
> That sounds like a homework question, why exactly do you need/want to
> know this, and what have you done already to try to figure it out
> yourself?
>
> greg k-h



-- 
My best regards to you.

     No System Is Safe!
     mudongliang


From greg at kroah.com  Fri Feb 19 00:06:05 2016
From: greg at kroah.com (Greg KH)
Date: Thu, 18 Feb 2016 21:06:05 -0800
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <CAKfJ7KJNiiV=xgdjDLm68nVORhg_CMdqeTVaEGor1K3X0jk69A@mail.gmail.com>
References: <20160215165231.GD21526@icarus.home.austad.us>
	<CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>
	<42173.1455599614@turing-police.cc.vt.edu>
	<20160216094252.194c7907@BR9TG4T3.de.ibm.com>
	<124507.1455640511@turing-police.cc.vt.edu>
	<CAKfJ7KKxoh3a-Yw4c+5Kf42gWxMiGam3JJ3u=HyhJ=uA7uMdoQ@mail.gmail.com>
	<21502.1455689456@turing-police.cc.vt.edu>
	<CAKfJ7K+1XjdSnXfUQD4Hp+oaGVzhvw_7w4A2SK9d8DgJ-t1-GA@mail.gmail.com>
	<20160217153242.GA15814@kroah.com>
	<CAKfJ7KJNiiV=xgdjDLm68nVORhg_CMdqeTVaEGor1K3X0jk69A@mail.gmail.com>
Message-ID: <20160219050605.GA11210@kroah.com>

On Thu, Feb 18, 2016 at 10:05:40AM +0530, Nitin Varyani wrote:
> @ Greg: Since I am very new to the field, with the huge task in hand
> and a short time span of 3 months given for this project,

3 months?  That's way too short, this is a multi-year/decade type
research project.  You can barely write a "simple" kernel driver in 3
months start to finish unless you _really_ know what you are doing.

I suggest get a new professor / advisor, this one doesn't seem to
realize the scope of the work involved :)

good luck!

greg k-h


From ruben at mrbrklyn.com  Fri Feb 19 10:31:10 2016
From: ruben at mrbrklyn.com (Ruben Safir)
Date: Fri, 19 Feb 2016 10:31:10 -0500
Subject: Distributed Process Scheduling Algorithm
In-Reply-To: <20160219050605.GA11210@kroah.com>
References: <CAKfJ7KJYt25rp0KSiR2QWPw0zP-WO1iVGmSD915v+9Ueq+xhPQ@mail.gmail.com>
	<42173.1455599614@turing-police.cc.vt.edu>
	<20160216094252.194c7907@BR9TG4T3.de.ibm.com>
	<124507.1455640511@turing-police.cc.vt.edu>
	<CAKfJ7KKxoh3a-Yw4c+5Kf42gWxMiGam3JJ3u=HyhJ=uA7uMdoQ@mail.gmail.com>
	<21502.1455689456@turing-police.cc.vt.edu>
	<CAKfJ7K+1XjdSnXfUQD4Hp+oaGVzhvw_7w4A2SK9d8DgJ-t1-GA@mail.gmail.com>
	<20160217153242.GA15814@kroah.com>
	<CAKfJ7KJNiiV=xgdjDLm68nVORhg_CMdqeTVaEGor1K3X0jk69A@mail.gmail.com>
	<20160219050605.GA11210@kroah.com>
Message-ID: <20160219153110.GA2358@www.mrbrklyn.com>

On Thu, Feb 18, 2016 at 09:06:05PM -0800, Greg KH wrote:
> On Thu, Feb 18, 2016 at 10:05:40AM +0530, Nitin Varyani wrote:
> > @ Greg: Since I am very new to the field, with the huge task in hand
> > and a short time span of 3 months given for this project,
> 
Are you formally trained froma  university?  I'm just asking because I know
that many core coders don't even have a college background in comp sci.  
So I'm just curious as to the path you took.

Reuvain


> 3 months?  That's way too short, this is a multi-year/decade type
> research project.  You can barely write a "simple" kernel driver in 3
> months start to finish unless you _really_ know what you are doing.
> 
> I suggest get a new professor / advisor, this one doesn't seem to
> realize the scope of the work involved :)
> 
> good luck!
> 
> greg k-h
> 
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

-- 
So many immigrant groups have swept through our town
that Brooklyn, like Atlantis, reaches mythological
proportions in the mind of the world - RI Safir 1998
http://www.mrbrklyn.com 

DRM is THEFT - We are the STAKEHOLDERS - RI Safir 2002
http://www.nylxs.com - Leadership Development in Free Software
http://www2.mrbrklyn.com/resources - Unpublished Archive 
http://www.coinhangout.com - coins!
http://www.brooklyn-living.com 

Being so tracked is for FARM ANIMALS and and extermination camps, 
but incompatible with living as a free human being. -RI Safir 2013



From tochansky at tochlab.net  Fri Feb 19 10:17:59 2016
From: tochansky at tochlab.net (tochansky at tochlab.net)
Date: Fri, 19 Feb 2016 18:17:59 +0300
Subject: Difference dma_alloc_coherent() in x86_32 and x86_64
Message-ID: <dc659340425f0e31019f830792ef5eee@tochlab.net>

Hello!

I have a driver for PCI device which uses CMA framework for allocating 
big coherent blocks of memory for DMA.

Allocation looks like:

typedef struct {
     struct list_head list;
     uint32_t size8;
     void *kaddr;
     dma_addr_t paddr;
} dma_region_t;

LIST_HEAD(region_list);

......

void* AllocDMA( size_t size )
{
     dma_region_t *new_region;
     new_region = kmalloc(sizeof(dma_region_t), GFP_KERNEL);
     new_region->size8 = size;

     new_region->kaddr = dma_alloc_coherent( NULL, size, 
&new_region->paddr, GFP_KERNEL | GFP_DMA32 );

     list_add(&new_region->list, &region_list);
     printk("pcidev: cma_alloc paddr %pad kaddr %p size %d\n", 
&new_region->paddr, new_region->kaddr, new_region->size8);
     return new_region->kaddr;

}

It works fine on kernel 3.18.26 in 32bit mode.
When I reconfigure same kernel to run in 64bit mode(enabling in 
'menuconfig' option '64-bit kernel') and trying to use this driver with 
it
allocation failed with message in dmesg:
...
[ 1393.835535]  fallback device: swiotlb buffer is full (sz: 8388608 
bytes)
[ 1393.835579] pcidev: cma_alloc paddr 0xffff880234861220 kaddr          
  (null) size 8388608
...

My kernel command line is: swiotlb=16384 iommu=soft cma=256M


Anyone can explain this strange behavior?


-- 
D


From mashemat at gmail.com  Sat Feb 20 05:08:23 2016
From: mashemat at gmail.com (masoud hematpour)
Date: Sat, 20 Feb 2016 11:08:23 +0100
Subject: call graph
Message-ID: <CABTiFJbK17hKrueXasR_+vMT0j0sf=OA1T0xyASrWEedwuiDqw@mail.gmail.com>

Hello all,

I need to create call graph of memory management. Is there any tool.
I found "cflow" but the output is not good enough. Can anyone help me in
preparing?
or I should prepare manually.


Thank you
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From mulyadi.santosa at gmail.com  Sat Feb 20 13:24:23 2016
From: mulyadi.santosa at gmail.com (Mulyadi Santosa)
Date: Sun, 21 Feb 2016 01:24:23 +0700
Subject: call graph
In-Reply-To: <CABTiFJbK17hKrueXasR_+vMT0j0sf=OA1T0xyASrWEedwuiDqw@mail.gmail.com>
References: <CABTiFJbK17hKrueXasR_+vMT0j0sf=OA1T0xyASrWEedwuiDqw@mail.gmail.com>
Message-ID: <CAGdaadYvhN7svCTnt-_Vqy1fnbEUySYRbBptVn1Ubek1B6ZSNA@mail.gmail.com>

On Sat, Feb 20, 2016 at 5:08 PM, masoud hematpour <mashemat at gmail.com>
wrote:

>
> Hello all,
>
> I need to create call graph of memory management. Is there any tool.
> I found "cflow" but the output is not good enough. Can anyone help me in
> preparing?
> or I should prepare manually.
>
>
> Thank you
>
> Hi...

Have you check CodeViz?
http://www.csn.ul.ie/~mel/projects/codeviz/

also check this blog entry:
http://deferred.io/2015/10/27/visualizing-linux-kernel-call-graphs.html

One advice: try to be more specific when generating call graph i.e graph of
page in. Other wise, you might find yourself generating too complex graph




-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com
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From andi.platschek at gmail.com  Sun Feb 21 02:54:20 2016
From: andi.platschek at gmail.com (Andreas Platschek)
Date: Sun, 21 Feb 2016 08:54:20 +0100
Subject: call graph
In-Reply-To: <CAGdaadYvhN7svCTnt-_Vqy1fnbEUySYRbBptVn1Ubek1B6ZSNA@mail.gmail.com>
References: <CABTiFJbK17hKrueXasR_+vMT0j0sf=OA1T0xyASrWEedwuiDqw@mail.gmail.com>
	<CAGdaadYvhN7svCTnt-_Vqy1fnbEUySYRbBptVn1Ubek1B6ZSNA@mail.gmail.com>
Message-ID: <56C96D2C.9090002@gmail.com>

Hi,

On 2016-02-20 19:24, Mulyadi Santosa wrote:
>
>
> On Sat, Feb 20, 2016 at 5:08 PM, masoud hematpour <mashemat at gmail.com 
> <mailto:mashemat at gmail.com>> wrote:
>
>
>     Hello all,
>
>     I need to create call graph of memory management. Is there any tool.
>     I found "cflow" but the output is not good enough. Can anyone help
>     me in preparing?
>     or I should prepare manually.
>
>
>     Thank you
>
> Hi...
>
> Have you check CodeViz?
> http://www.csn.ul.ie/~mel/projects/codeviz/ 
> <http://www.csn.ul.ie/%7Emel/projects/codeviz/>
>
I just looked at codeviz 2 weeks ago, and I would recommend to use the 
"alternative method" with ncc
(http://students.ceid.upatras.gr/~sxanth/ncc/) as it is a lot simpler to 
set it up (no need for a patched
version of gcc, etc.) and it is able to traverse function pointers.

thx!
andi

> also check this blog entry:
> http://deferred.io/2015/10/27/visualizing-linux-kernel-call-graphs.html
>
> One advice: try to be more specific when generating call graph i.e 
> graph of page in. Other wise, you might find yourself generating too 
> complex graph
>
>
>
>
> -- 
> regards,
>
> Mulyadi Santosa
> Freelance Linux trainer and consultant
>
> blog: the-hydra.blogspot.com <http://the-hydra.blogspot.com>
> training: mulyaditraining.blogspot.com 
> <http://mulyaditraining.blogspot.com>
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies



From mashemat at gmail.com  Sun Feb 21 05:46:05 2016
From: mashemat at gmail.com (masoud hematpour)
Date: Sun, 21 Feb 2016 11:46:05 +0100
Subject: call graph
In-Reply-To: <56C96D2C.9090002@gmail.com>
References: <CABTiFJbK17hKrueXasR_+vMT0j0sf=OA1T0xyASrWEedwuiDqw@mail.gmail.com>
	<CAGdaadYvhN7svCTnt-_Vqy1fnbEUySYRbBptVn1Ubek1B6ZSNA@mail.gmail.com>
	<56C96D2C.9090002@gmail.com>
Message-ID: <CABTiFJZ_nqhP6_aKXC51a0WV1BR9D7G3+UkqA8c2rVACjCbcyw@mail.gmail.com>

Thank you all specially mulyadi!!!
I installed Egypt. It works fine.

On Sun, Feb 21, 2016 at 8:54 AM, Andreas Platschek <andi.platschek at gmail.com
> wrote:

> Hi,
>
> On 2016-02-20 19:24, Mulyadi Santosa wrote:
> >
> >
> > On Sat, Feb 20, 2016 at 5:08 PM, masoud hematpour <mashemat at gmail.com
> > <mailto:mashemat at gmail.com>> wrote:
> >
> >
> >     Hello all,
> >
> >     I need to create call graph of memory management. Is there any tool.
> >     I found "cflow" but the output is not good enough. Can anyone help
> >     me in preparing?
> >     or I should prepare manually.
> >
> >
> >     Thank you
> >
> > Hi...
> >
> > Have you check CodeViz?
> > http://www.csn.ul.ie/~mel/projects/codeviz/
> > <http://www.csn.ul.ie/%7Emel/projects/codeviz/>
> >
> I just looked at codeviz 2 weeks ago, and I would recommend to use the
> "alternative method" with ncc
> (http://students.ceid.upatras.gr/~sxanth/ncc/) as it is a lot simpler to
> set it up (no need for a patched
> version of gcc, etc.) and it is able to traverse function pointers.
>
> thx!
> andi
>
> > also check this blog entry:
> > http://deferred.io/2015/10/27/visualizing-linux-kernel-call-graphs.html
> >
> > One advice: try to be more specific when generating call graph i.e
> > graph of page in. Other wise, you might find yourself generating too
> > complex graph
> >
> >
> >
> >
> > --
> > regards,
> >
> > Mulyadi Santosa
> > Freelance Linux trainer and consultant
> >
> > blog: the-hydra.blogspot.com <http://the-hydra.blogspot.com>
> > training: mulyaditraining.blogspot.com
> > <http://mulyaditraining.blogspot.com>
> >
> >
> > _______________________________________________
> > Kernelnewbies mailing list
> > Kernelnewbies at kernelnewbies.org
> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
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From mulyadi.santosa at gmail.com  Sun Feb 21 10:27:48 2016
From: mulyadi.santosa at gmail.com (Mulyadi Santosa)
Date: Sun, 21 Feb 2016 22:27:48 +0700
Subject: call graph
In-Reply-To: <CABTiFJZ_nqhP6_aKXC51a0WV1BR9D7G3+UkqA8c2rVACjCbcyw@mail.gmail.com>
References: <CABTiFJbK17hKrueXasR_+vMT0j0sf=OA1T0xyASrWEedwuiDqw@mail.gmail.com>
	<CAGdaadYvhN7svCTnt-_Vqy1fnbEUySYRbBptVn1Ubek1B6ZSNA@mail.gmail.com>
	<56C96D2C.9090002@gmail.com>
	<CABTiFJZ_nqhP6_aKXC51a0WV1BR9D7G3+UkqA8c2rVACjCbcyw@mail.gmail.com>
Message-ID: <CAGdaadbCPTUX10BNPz+MXM80Z1wOUX6rbFhN6RHS7vO95c=Ndw@mail.gmail.com>

On Sun, Feb 21, 2016 at 5:46 PM, masoud hematpour <mashemat at gmail.com>
wrote:

> Thank you all specially mulyadi!!!
> I installed Egypt. It works fine.
>
> On Sun, Feb 21, 2016 at 8:54 AM, Andreas Platschek <
> andi.platschek at gmail.com> wrote:
>
>> Hi,
>>
>> On 2016-02-20 19:24, Mulyadi Santosa wrote:
>> >
>> >
>> > On Sat, Feb 20, 2016 at 5:08 PM, masoud hematpour <mashemat at gmail.com
>> > <mailto:mashemat at gmail.com>> wrote:
>> >
>> >
>> >     Hello all,
>> >
>> >     I need to create call graph of memory management. Is there any tool.
>> >     I found "cflow" but the output is not good enough. Can anyone help
>> >     me in preparing?
>> >     or I should prepare manually.
>> >
>> >
>> >     Thank you
>> >
>> > Hi...
>> >
>> > Have you check CodeViz?
>> > http://www.csn.ul.ie/~mel/projects/codeviz/
>> > <http://www.csn.ul.ie/%7Emel/projects/codeviz/>
>> >
>> I just looked at codeviz 2 weeks ago, and I would recommend to use the
>> "alternative method" with ncc
>> (http://students.ceid.upatras.gr/~sxanth/ncc/) as it is a lot simpler to
>> set it up (no need for a patched
>> version of gcc, etc.) and it is able to traverse function pointers.
>>
>> thx!
>> andi
>>
>> > also check this blog entry:
>> > http://deferred.io/2015/10/27/visualizing-linux-kernel-call-graphs.html
>> >
>> > One advice: try to be more specific when generating call graph i.e
>> > graph of page in. Other wise, you might find yourself generating too
>> > complex graph
>> >
>> >
>> >
>> >
>> > --
>> > regards,
>> >
>> > Mulyadi Santosa
>> > Freelance Linux trainer and consultant
>> >
>> > blog: the-hydra.blogspot.com <http://the-hydra.blogspot.com>
>> > training: mulyaditraining.blogspot.com
>> > <http://mulyaditraining.blogspot.com>
>> >
>> >
>> > _______________________________________________
>> > Kernelnewbies mailing list
>> > Kernelnewbies at kernelnewbies.org
>> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>

You welcome Masoud.

Oh and next time, please don't top post :)


-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com
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From yuzibode at 126.com  Sun Feb 21 11:29:54 2016
From: yuzibode at 126.com (YU Bo)
Date: Mon, 22 Feb 2016 00:29:54 +0800 (CST)
Subject: Why exist coding style issue in mm_types.h
Message-ID: <533016df.21f9.15304aa7a61.Coremail.yuzibode@126.com>

Hi,
  When  read the source code of mm_types.h, i encounter _coding style_ code ,such like:
http://lxr.free-electrons.com/source/include/linux/mm_types.h#L346 in comments.
Why not try to fix it? Because it is trival? 
Actually, checkpatch.pl reports many errors and warnnings for it.
Only can i fix the coding style issue in staging?
Sorry for the noisy. 




--
Best Regards
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From greg at kroah.com  Sun Feb 21 13:27:39 2016
From: greg at kroah.com (Greg KH)
Date: Sun, 21 Feb 2016 10:27:39 -0800
Subject: Why exist coding style issue in mm_types.h
In-Reply-To: <533016df.21f9.15304aa7a61.Coremail.yuzibode@126.com>
References: <533016df.21f9.15304aa7a61.Coremail.yuzibode@126.com>
Message-ID: <20160221182739.GB29890@kroah.com>

On Mon, Feb 22, 2016 at 12:29:54AM +0800, YU Bo wrote:
> Hi,
>   When  read the source code of mm_types.h, i encounter _coding style_ code
> ,such like:
> http://lxr.free-electrons.com/source/include/linux/mm_types.h#L346 in comments.
> Why not try to fix it? Because it is trival? 
> Actually, checkpatch.pl reports many errors and warnnings for it.
> Only can i fix the coding style issue in staging?

Yes, stick to drivers/staging/* only for coding style fixes please.



From ruben at mrbrklyn.com  Sun Feb 21 17:34:38 2016
From: ruben at mrbrklyn.com (Ruben Safir)
Date: Sun, 21 Feb 2016 17:34:38 -0500
Subject: can't read this
Message-ID: <56CA3B7E.7070106@mrbrklyn.com>


ASCII?


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MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

_______________________________________________
Kernelnewbies mailing list
Kernelnewbies at kernelnewbies.org
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

--===============3901919624009551412==--
-- 
So many immigrant groups have swept through our town
that Brooklyn, like Atlantis, reaches mythological
proportions in the mind of the world - RI Safir 1998
http://www.mrbrklyn.com

DRM is THEFT - We are the STAKEHOLDERS - RI Safir 2002
http://www.nylxs.com - Leadership Development in Free Software
http://www2.mrbrklyn.com/resources - Unpublished Archive
http://www.coinhangout.com - coins!
http://www.brooklyn-living.com

Being so tracked is for FARM ANIMALS and and extermination camps,
but incompatible with living as a free human being. -RI Safir 2013


From aruna.hewapathirane at gmail.com  Sun Feb 21 20:03:30 2016
From: aruna.hewapathirane at gmail.com (Aruna Hewapathirane)
Date: Sun, 21 Feb 2016 20:03:30 -0500
Subject: can't read this
In-Reply-To: <56CA3B7E.7070106@mrbrklyn.com>
References: <56CA3B7E.7070106@mrbrklyn.com>
Message-ID: <CAFSeFg-TKd1NTMeGDKdkaZ5u9A9t7W8Ck9u6v8mYEGYNUAEE9g@mail.gmail.com>

>> On Sun, Feb 21, 2016 at 5:34 PM, Ruben Safir <ruben at mrbrklyn.com> wrote:
>> ASCII?

It is base64 encoding,  if you look at the header it says
Content-Transfer-Encoding: base64.

Please cut and paste the 'content' into this https://www.base64decode.org/
and click decode.

The original message was from YU Bo and from the header you can see
Content-Type: text/plain; charset=GBK. charset=GBK is GBK is an extension
of the GB2312 character set for simplified Chinese characters, used in the
People's Republic of China.

When decoded it shows:
---------------------------------------------------------------------------------------------------------------------------------
Hi,
  When  read the source code of mm_types.h, i encounter _coding style_ code
,such like:
http://lxr.free-electrons.com/source/include/linux/mm_types.h#L346 in
comments.
Why not try to fix it? Because it is trival?
Actually, checkpatch.pl reports many errors and warnnings for it.
Only can i fix the coding style issue in staging?
Sorry for the noisy.
---------------------------------------------------------------------------------------------------------------------------------

Hope that helps :)

Aruna

>> --===============3901919624009551412==
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> ------=_Part_49324_945639701.1456072194657--
>
>
>
> --===============3901919624009551412==
> Content-Type: text/plain; charset="us-ascii"
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Content-Disposition: inline
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
> --===============3901919624009551412==--
> --
> So many immigrant groups have swept through our town
> that Brooklyn, like Atlantis, reaches mythological
> proportions in the mind of the world - RI Safir 1998
> http://www.mrbrklyn.com
>
> DRM is THEFT - We are the STAKEHOLDERS - RI Safir 2002
> http://www.nylxs.com - Leadership Development in Free Software
> http://www2.mrbrklyn.com/resources - Unpublished Archive
> http://www.coinhangout.com - coins!
> http://www.brooklyn-living.com
>
> Being so tracked is for FARM ANIMALS and and extermination camps,
> but incompatible with living as a free human being. -RI Safir 2013
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
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From Valdis.Kletnieks at vt.edu  Sun Feb 21 21:30:40 2016
From: Valdis.Kletnieks at vt.edu (Valdis.Kletnieks at vt.edu)
Date: Sun, 21 Feb 2016 21:30:40 -0500
Subject: can't read this
In-Reply-To: <56CA3B7E.7070106@mrbrklyn.com>
References: <56CA3B7E.7070106@mrbrklyn.com>
Message-ID: <186563.1456108240@turing-police.cc.vt.edu>

On Sun, 21 Feb 2016 17:34:38 -0500, Ruben Safir said:
> > ASCII?

No.

> Content-Type: text/plain; charset=GBK
> Content-Transfer-Encoding: base64

It claims to be some mostly-nonstandard variety of Chinese.

https://en.wikipedia.org/wiki/GBK
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From yuzibode at 126.com  Sun Feb 21 21:52:46 2016
From: yuzibode at 126.com (YU Bo)
Date: Mon, 22 Feb 2016 10:52:46 +0800 (CST)
Subject: can't read this
In-Reply-To: <186563.1456108240@turing-police.cc.vt.edu>
References: <56CA3B7E.7070106@mrbrklyn.com>
	<186563.1456108240@turing-police.cc.vt.edu>
Message-ID: <f8719c8.1a7d.15306e4bc17.Coremail.yuzibode@126.com>

Hi,


At 2016-02-22 10:30:40, Valdis.Kletnieks at vt.edu wrote: >On Sun, 21 Feb 2016 17:34:38 -0500, Ruben Safir said: >> > ASCII? > >No. > >> Content-Type: text/plain; charset=GBK >> Content-Transfer-Encoding: base64 > >It claims to be some mostly-nonstandard variety of Chinese. > >https://en.wikipedia.org/wiki/GBK
 I will configure my email-client.
Sorry for the noisy cause from me.
--
Best Regards
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From sunitad100 at gmail.com  Mon Feb 22 00:24:54 2016
From: sunitad100 at gmail.com (SUNITA)
Date: Mon, 22 Feb 2016 10:54:54 +0530
Subject: Project Idea..
Message-ID: <CAMEb3oqQ3-cx0faqCxJTNkK8A5tjs_ozZ0X6-FycBvdOt2K=KQ@mail.gmail.com>

Respected Sir/Madam,
I am trying to study the effect of Scheduler Policies on Energy
Consumption of Portable Device.

This will be achieved by modifying the current Completely Fair
Scheduler by changing the range of nice values from 40 to 100 and
adding a new scheduing policy.
CFS uses SCHED_RR, SCHED_FCFS, SCHED_OTHER, SCHED_BATCH Policy for
scheduling any process.  The idea is to insert a new scheduling policy
by modifying the header files.

Can this be a good topic to carry out research.I welcome any other
idea related Linux Kernel CFS.

Regards,
SUNIITA


From yuzibode at 126.com  Mon Feb 22 00:05:29 2016
From: yuzibode at 126.com (YU Bo)
Date: Mon, 22 Feb 2016 13:05:29 +0800 (CST)
Subject: Why exist coding style issue in mm_types.h
In-Reply-To: <20160221182739.GB29890@kroah.com>
References: <533016df.21f9.15304aa7a61.Coremail.yuzibode@126.com>
	<20160221182739.GB29890@kroah.com>
Message-ID: <5dfbf723.561d.153075e3acb.Coremail.yuzibode@126.com>

Hi,
At 2016-02-22 02:27:39, "Greg KH" <greg at kroah.com> wrote:
>On Mon, Feb 22, 2016 at 12:29:54AM +0800, YU Bo wrote:
>> Hi,
>>   When  read the source code of mm_types.h, i encounter _coding style_ code
>> ,such like:
>> http://lxr.free-electrons.com/source/include/linux/mm_types.h#L346 in comments.
>> Why not try to fix it? Because it is trival? 
>> Actually, checkpatch.pl reports many errors and warnnings for it.
>> Only can i fix the coding style issue in staging?
>
>Yes, stick to drivers/staging/* only for coding style fixes please.

>
Thanks a lot!
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From mulyadi.santosa at gmail.com  Mon Feb 22 00:45:06 2016
From: mulyadi.santosa at gmail.com (Mulyadi Santosa)
Date: Mon, 22 Feb 2016 12:45:06 +0700
Subject: Project Idea..
In-Reply-To: <CAMEb3oqQ3-cx0faqCxJTNkK8A5tjs_ozZ0X6-FycBvdOt2K=KQ@mail.gmail.com>
References: <CAMEb3oqQ3-cx0faqCxJTNkK8A5tjs_ozZ0X6-FycBvdOt2K=KQ@mail.gmail.com>
Message-ID: <CAGdaadYaCvUqxDOqax430gDH1OVfJd+xZjvSq_qNX9vWnm-hjw@mail.gmail.com>

On Mon, Feb 22, 2016 at 12:24 PM, SUNITA <sunitad100 at gmail.com> wrote:

> Respected Sir/Madam,
> I am trying to study the effect of Scheduler Policies on Energy
> Consumption of Portable Device.
>
> This will be achieved by modifying the current Completely Fair
> Scheduler by changing the range of nice values from 40 to 100 and
> adding a new scheduing policy.
> CFS uses SCHED_RR, SCHED_FCFS, SCHED_OTHER, SCHED_BATCH Policy for
> scheduling any process.  The idea is to insert a new scheduling policy
> by modifying the header files.
>
> Can this be a good topic to carry out research.I welcome any other
> idea related Linux Kernel CFS.
>
> Regards,
> SUNIITA
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>

Hi Suniita

Sounds challenging.

It might be good topic. Just make sure you understand how to measure power
consumption and prepare various scenario of load simulation to mimic real
power consumption pattern.


-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

This email has been sent from a virus-free computer protected by Avast.
www.avast.com <https://www.avast.com/sig-email>
<#DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
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From anilcoll90 at gmail.com  Mon Feb 22 00:56:31 2016
From: anilcoll90 at gmail.com (Anil Nair)
Date: Mon, 22 Feb 2016 11:26:31 +0530
Subject: Books Regarding Linux Kernel
Message-ID: <CAHkwNTks=fV-dUon2Y7UstJDQXLfSXF=q_XKkfSEiikDbBfmbQ@mail.gmail.com>

Hi,

Can anyone suggest any good book for understanding the Linux Kernel?

Are these books enough for understanding workings of Linux Kernel?

1.Linux Kernel in a Nutshell
2.Linux Device Drivers, Third Edition
3.Linux Kernel Development (3rd Edition)


-- 
--
Regards,
Anil Nair


From klshiva4a4 at gmail.com  Mon Feb 22 01:00:01 2016
From: klshiva4a4 at gmail.com (Shiva Shankar)
Date: Mon, 22 Feb 2016 11:30:01 +0530
Subject: Books Regarding Linux Kernel
In-Reply-To: <CAHkwNTks=fV-dUon2Y7UstJDQXLfSXF=q_XKkfSEiikDbBfmbQ@mail.gmail.com>
References: <CAHkwNTks=fV-dUon2Y7UstJDQXLfSXF=q_XKkfSEiikDbBfmbQ@mail.gmail.com>
Message-ID: <CAKe3+gL0FfQkAYCac_rMZHcSQZ=c3aNaD8oP66MmO1MoNP4+BQ@mail.gmail.com>

Hi Anil,
Listed books are enough to start programming.

You can also refer to
Professional Linux Kernel Architecture
Book by Wolfgang Mauerer

Thanks


On Mon, Feb 22, 2016 at 11:26 AM, Anil Nair <anilcoll90 at gmail.com> wrote:

> Hi,
>
> Can anyone suggest any good book for understanding the Linux Kernel?
>
> Are these books enough for understanding workings of Linux Kernel?
>
> 1.Linux Kernel in a Nutshell
> 2.Linux Device Drivers, Third Edition
> 3.Linux Kernel Development (3rd Edition)
>
>
> --
> --
> Regards,
> Anil Nair
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
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From kennethadammiller at gmail.com  Mon Feb 22 01:00:59 2016
From: kennethadammiller at gmail.com (Kenneth Adam Miller)
Date: Mon, 22 Feb 2016 01:00:59 -0500
Subject: Books Regarding Linux Kernel
In-Reply-To: <CAHkwNTks=fV-dUon2Y7UstJDQXLfSXF=q_XKkfSEiikDbBfmbQ@mail.gmail.com>
References: <CAHkwNTks=fV-dUon2Y7UstJDQXLfSXF=q_XKkfSEiikDbBfmbQ@mail.gmail.com>
Message-ID: <CAK7rcp9AD7KoQ61tjnT4iw-_dv98XeLZZDzaoq8mkrSfzT44Gw@mail.gmail.com>

Those are the popular three, but the documentation provided by kernel
authors themselves as well as source code is also expected.

Lastly, semantics of the machine are often a required read. The intel
manual might be something that belongs on your list, if you want to truly
understand.

But no book is really enough to completely understand the linux kernel.
Those just help you get started.

On Mon, Feb 22, 2016 at 12:56 AM, Anil Nair <anilcoll90 at gmail.com> wrote:

> Hi,
>
> Can anyone suggest any good book for understanding the Linux Kernel?
>
> Are these books enough for understanding workings of Linux Kernel?
>
> 1.Linux Kernel in a Nutshell
> 2.Linux Device Drivers, Third Edition
> 3.Linux Kernel Development (3rd Edition)
>
>
> --
> --
> Regards,
> Anil Nair
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
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From sanjeevsharmaengg at gmail.com  Mon Feb 22 01:02:05 2016
From: sanjeevsharmaengg at gmail.com (sanjeev sharma)
Date: Mon, 22 Feb 2016 11:32:05 +0530
Subject: Books Regarding Linux Kernel
In-Reply-To: <CAKe3+gL0FfQkAYCac_rMZHcSQZ=c3aNaD8oP66MmO1MoNP4+BQ@mail.gmail.com>
References: <CAHkwNTks=fV-dUon2Y7UstJDQXLfSXF=q_XKkfSEiikDbBfmbQ@mail.gmail.com>
	<CAKe3+gL0FfQkAYCac_rMZHcSQZ=c3aNaD8oP66MmO1MoNP4+BQ@mail.gmail.com>
Message-ID: <CAGUYZuT_jj3eWKwv8=nGkREPFK-5qXTNSXVFGPr01_AMeSR4gw@mail.gmail.com>

Hello,

Please don't forget to read Linux Kernel by Robert Love.It is very good for
beginner.

Regards
Sanjeev Sharma

On Mon, Feb 22, 2016 at 11:30 AM, Shiva Shankar <klshiva4a4 at gmail.com>
wrote:

> Hi Anil,
> Listed books are enough to start programming.
>
> You can also refer to
> Professional Linux Kernel Architecture
> Book by Wolfgang Mauerer
>
> Thanks
>
>
> On Mon, Feb 22, 2016 at 11:26 AM, Anil Nair <anilcoll90 at gmail.com> wrote:
>
>> Hi,
>>
>> Can anyone suggest any good book for understanding the Linux Kernel?
>>
>> Are these books enough for understanding workings of Linux Kernel?
>>
>> 1.Linux Kernel in a Nutshell
>> 2.Linux Device Drivers, Third Edition
>> 3.Linux Kernel Development (3rd Edition)
>>
>>
>> --
>> --
>> Regards,
>> Anil Nair
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
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From anilcoll90 at gmail.com  Mon Feb 22 01:05:39 2016
From: anilcoll90 at gmail.com (Anil Nair)
Date: Mon, 22 Feb 2016 11:35:39 +0530
Subject: Books Regarding Linux Kernel
In-Reply-To: <CAGUYZuT_jj3eWKwv8=nGkREPFK-5qXTNSXVFGPr01_AMeSR4gw@mail.gmail.com>
References: <CAHkwNTks=fV-dUon2Y7UstJDQXLfSXF=q_XKkfSEiikDbBfmbQ@mail.gmail.com>
	<CAKe3+gL0FfQkAYCac_rMZHcSQZ=c3aNaD8oP66MmO1MoNP4+BQ@mail.gmail.com>
	<CAGUYZuT_jj3eWKwv8=nGkREPFK-5qXTNSXVFGPr01_AMeSR4gw@mail.gmail.com>
Message-ID: <CAHkwNT=Rh7a-un8s4GN4fhrRZvCsq3jA2MA3GXBuCAW_myMeUQ@mail.gmail.com>

Hi,

On Mon, Feb 22, 2016 at 11:32 AM, sanjeev sharma
<sanjeevsharmaengg at gmail.com> wrote:
> Hello,
>
> Please don't forget to read Linux Kernel by Robert Love.It is very good for
> beginner.
>
> Regards
> Sanjeev Sharma
>
> On Mon, Feb 22, 2016 at 11:30 AM, Shiva Shankar <klshiva4a4 at gmail.com>
> wrote:
>>
>> Hi Anil,
>> Listed books are enough to start programming.
>>
>> You can also refer to
>> Professional Linux Kernel Architecture
>> Book by Wolfgang Mauerer
>>
>> Thanks
>>
>>
>> On Mon, Feb 22, 2016 at 11:26 AM, Anil Nair <anilcoll90 at gmail.com> wrote:
>>>
>>> Hi,
>>>
>>> Can anyone suggest any good book for understanding the Linux Kernel?
>>>
>>> Are these books enough for understanding workings of Linux Kernel?
>>>
>>> 1.Linux Kernel in a Nutshell
>>> 2.Linux Device Drivers, Third Edition
>>> 3.Linux Kernel Development (3rd Edition)
>>>
>>>
>>> --
>>> --
>>> Regards,
>>> Anil Nair
>>>
>>> _______________________________________________
>>> Kernelnewbies mailing list
>>> Kernelnewbies at kernelnewbies.org
>>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>>
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>

Thanks Guys for the help. :)

-- 
--
Regards,
Anil Nair


From subodhtechno at gmail.com  Mon Feb 22 01:51:46 2016
From: subodhtechno at gmail.com (subodh sawrav)
Date: Mon, 22 Feb 2016 12:21:46 +0530
Subject: Books Regarding Linux Kernel
In-Reply-To: <CAHkwNT=Rh7a-un8s4GN4fhrRZvCsq3jA2MA3GXBuCAW_myMeUQ@mail.gmail.com>
References: <CAHkwNTks=fV-dUon2Y7UstJDQXLfSXF=q_XKkfSEiikDbBfmbQ@mail.gmail.com>
	<CAKe3+gL0FfQkAYCac_rMZHcSQZ=c3aNaD8oP66MmO1MoNP4+BQ@mail.gmail.com>
	<CAGUYZuT_jj3eWKwv8=nGkREPFK-5qXTNSXVFGPr01_AMeSR4gw@mail.gmail.com>
	<CAHkwNT=Rh7a-un8s4GN4fhrRZvCsq3jA2MA3GXBuCAW_myMeUQ@mail.gmail.com>
Message-ID: <CAKyLyO+HBZegsvw=ksFhqKG=xNO0iM_PtA4gyEbKg+SGYC+iFw@mail.gmail.com>

My recommendation will be to start with "Linux Kernel Development" by
Robert Love.
It's the best book to start with.

Regards,
Subodh

On Mon, Feb 22, 2016 at 11:35 AM, Anil Nair <anilcoll90 at gmail.com> wrote:

> Hi,
>
> On Mon, Feb 22, 2016 at 11:32 AM, sanjeev sharma
> <sanjeevsharmaengg at gmail.com> wrote:
> > Hello,
> >
> > Please don't forget to read Linux Kernel by Robert Love.It is very good
> for
> > beginner.
> >
> > Regards
> > Sanjeev Sharma
> >
> > On Mon, Feb 22, 2016 at 11:30 AM, Shiva Shankar <klshiva4a4 at gmail.com>
> > wrote:
> >>
> >> Hi Anil,
> >> Listed books are enough to start programming.
> >>
> >> You can also refer to
> >> Professional Linux Kernel Architecture
> >> Book by Wolfgang Mauerer
> >>
> >> Thanks
> >>
> >>
> >> On Mon, Feb 22, 2016 at 11:26 AM, Anil Nair <anilcoll90 at gmail.com>
> wrote:
> >>>
> >>> Hi,
> >>>
> >>> Can anyone suggest any good book for understanding the Linux Kernel?
> >>>
> >>> Are these books enough for understanding workings of Linux Kernel?
> >>>
> >>> 1.Linux Kernel in a Nutshell
> >>> 2.Linux Device Drivers, Third Edition
> >>> 3.Linux Kernel Development (3rd Edition)
> >>>
> >>>
> >>> --
> >>> --
> >>> Regards,
> >>> Anil Nair
> >>>
> >>> _______________________________________________
> >>> Kernelnewbies mailing list
> >>> Kernelnewbies at kernelnewbies.org
> >>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >>
> >>
> >>
> >> _______________________________________________
> >> Kernelnewbies mailing list
> >> Kernelnewbies at kernelnewbies.org
> >> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >>
> >
>
> Thanks Guys for the help. :)
>
> --
> --
> Regards,
> Anil Nair
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
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From mbobrowski at mbobrowski.org  Mon Feb 22 01:53:33 2016
From: mbobrowski at mbobrowski.org (Matthew Bobrowski)
Date: Mon, 22 Feb 2016 17:53:33 +1100
Subject: Books Regarding Linux Kernel
In-Reply-To: <CAHkwNT=Rh7a-un8s4GN4fhrRZvCsq3jA2MA3GXBuCAW_myMeUQ@mail.gmail.com>
References: <CAHkwNTks=fV-dUon2Y7UstJDQXLfSXF=q_XKkfSEiikDbBfmbQ@mail.gmail.com>
	<CAKe3+gL0FfQkAYCac_rMZHcSQZ=c3aNaD8oP66MmO1MoNP4+BQ@mail.gmail.com>
	<CAGUYZuT_jj3eWKwv8=nGkREPFK-5qXTNSXVFGPr01_AMeSR4gw@mail.gmail.com>
	<CAHkwNT=Rh7a-un8s4GN4fhrRZvCsq3jA2MA3GXBuCAW_myMeUQ@mail.gmail.com>
Message-ID: <CAC0goKeyVkbkWOKK=62Q-=TqJRpPNTUki83K0407p8Vi+6+XoQ@mail.gmail.com>

Completely agree with Kenneth.

Best of luck!

--

Kind regards,
Matthew Bobrowski


On Mon, Feb 22, 2016 at 5:05 PM, Anil Nair <anilcoll90 at gmail.com> wrote:
> Hi,
>
> On Mon, Feb 22, 2016 at 11:32 AM, sanjeev sharma
> <sanjeevsharmaengg at gmail.com> wrote:
>> Hello,
>>
>> Please don't forget to read Linux Kernel by Robert Love.It is very good for
>> beginner.
>>
>> Regards
>> Sanjeev Sharma
>>
>> On Mon, Feb 22, 2016 at 11:30 AM, Shiva Shankar <klshiva4a4 at gmail.com>
>> wrote:
>>>
>>> Hi Anil,
>>> Listed books are enough to start programming.
>>>
>>> You can also refer to
>>> Professional Linux Kernel Architecture
>>> Book by Wolfgang Mauerer
>>>
>>> Thanks
>>>
>>>
>>> On Mon, Feb 22, 2016 at 11:26 AM, Anil Nair <anilcoll90 at gmail.com> wrote:
>>>>
>>>> Hi,
>>>>
>>>> Can anyone suggest any good book for understanding the Linux Kernel?
>>>>
>>>> Are these books enough for understanding workings of Linux Kernel?
>>>>
>>>> 1.Linux Kernel in a Nutshell
>>>> 2.Linux Device Drivers, Third Edition
>>>> 3.Linux Kernel Development (3rd Edition)
>>>>
>>>>
>>>> --
>>>> --
>>>> Regards,
>>>> Anil Nair
>>>>
>>>> _______________________________________________
>>>> Kernelnewbies mailing list
>>>> Kernelnewbies at kernelnewbies.org
>>>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>>
>>>
>>>
>>> _______________________________________________
>>> Kernelnewbies mailing list
>>> Kernelnewbies at kernelnewbies.org
>>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>>
>>
>
> Thanks Guys for the help. :)
>
> --
> --
> Regards,
> Anil Nair
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies


From danielhilst at gmail.com  Mon Feb 22 09:49:51 2016
From: danielhilst at gmail.com (Daniel.)
Date: Mon, 22 Feb 2016 11:49:51 -0300
Subject: Books Regarding Linux Kernel
In-Reply-To: <CAC0goKeyVkbkWOKK=62Q-=TqJRpPNTUki83K0407p8Vi+6+XoQ@mail.gmail.com>
References: <CAHkwNTks=fV-dUon2Y7UstJDQXLfSXF=q_XKkfSEiikDbBfmbQ@mail.gmail.com>
	<CAKe3+gL0FfQkAYCac_rMZHcSQZ=c3aNaD8oP66MmO1MoNP4+BQ@mail.gmail.com>
	<CAGUYZuT_jj3eWKwv8=nGkREPFK-5qXTNSXVFGPr01_AMeSR4gw@mail.gmail.com>
	<CAHkwNT=Rh7a-un8s4GN4fhrRZvCsq3jA2MA3GXBuCAW_myMeUQ@mail.gmail.com>
	<CAC0goKeyVkbkWOKK=62Q-=TqJRpPNTUki83K0407p8Vi+6+XoQ@mail.gmail.com>
Message-ID: <CAF3SDA5BaJjDvGWCFa0_UTFnv2HqhtAxn1tvh5UQbvg9tx3s7w@mail.gmail.com>

There is Understanding the Linux Kernel, Daniel P. Bovet, Marco Cesati

LKD by Love is a really good book, I love it!
LDD3 can be found at http://www.makelinux.net/ldd3/

I suggest the documentation from the source too:
https://www.kernel.org/doc/Documentation/

Best regards and good reading :)

2016-02-22 3:53 GMT-03:00 Matthew Bobrowski <mbobrowski at mbobrowski.org>:
> Completely agree with Kenneth.
>
> Best of luck!
>
> --
>
> Kind regards,
> Matthew Bobrowski
>
>
> On Mon, Feb 22, 2016 at 5:05 PM, Anil Nair <anilcoll90 at gmail.com> wrote:
>> Hi,
>>
>> On Mon, Feb 22, 2016 at 11:32 AM, sanjeev sharma
>> <sanjeevsharmaengg at gmail.com> wrote:
>>> Hello,
>>>
>>> Please don't forget to read Linux Kernel by Robert Love.It is very good for
>>> beginner.
>>>
>>> Regards
>>> Sanjeev Sharma
>>>
>>> On Mon, Feb 22, 2016 at 11:30 AM, Shiva Shankar <klshiva4a4 at gmail.com>
>>> wrote:
>>>>
>>>> Hi Anil,
>>>> Listed books are enough to start programming.
>>>>
>>>> You can also refer to
>>>> Professional Linux Kernel Architecture
>>>> Book by Wolfgang Mauerer
>>>>
>>>> Thanks
>>>>
>>>>
>>>> On Mon, Feb 22, 2016 at 11:26 AM, Anil Nair <anilcoll90 at gmail.com> wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>> Can anyone suggest any good book for understanding the Linux Kernel?
>>>>>
>>>>> Are these books enough for understanding workings of Linux Kernel?
>>>>>
>>>>> 1.Linux Kernel in a Nutshell
>>>>> 2.Linux Device Drivers, Third Edition
>>>>> 3.Linux Kernel Development (3rd Edition)
>>>>>
>>>>>
>>>>> --
>>>>> --
>>>>> Regards,
>>>>> Anil Nair
>>>>>
>>>>> _______________________________________________
>>>>> Kernelnewbies mailing list
>>>>> Kernelnewbies at kernelnewbies.org
>>>>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Kernelnewbies mailing list
>>>> Kernelnewbies at kernelnewbies.org
>>>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>>>
>>>
>>
>> Thanks Guys for the help. :)
>>
>> --
>> --
>> Regards,
>> Anil Nair
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies



-- 
"Do or do not. There is no try"
  Yoda Master


From sriraamlinux at gmail.com  Mon Feb 22 10:15:34 2016
From: sriraamlinux at gmail.com (Sriraam VG)
Date: Mon, 22 Feb 2016 20:45:34 +0530
Subject: Kernelnewbies Digest, Vol 63, Issue 37
In-Reply-To: <mailman.230.1456120927.2430.kernelnewbies@kernelnewbies.org>
References: <mailman.230.1456120927.2430.kernelnewbies@kernelnewbies.org>
Message-ID: <CAEG7vdGQnfv-Kq1hrJV-KmD+3ebukGg_b2kmp-m1c6-FRWvimQ@mail.gmail.com>

Can someone suggest me a book on how to start contributing for linux
kernel or any tutorial videos or any leads ?

Thanks and regards
Sriraam VG

On Mon, Feb 22, 2016 at 11:32 AM,
<kernelnewbies-request at kernelnewbies.org> wrote:
> Send Kernelnewbies mailing list submissions to
>         kernelnewbies at kernelnewbies.org
>
> To subscribe or unsubscribe via the World Wide Web, visit
>         http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> or, via email, send a message with subject or body 'help' to
>         kernelnewbies-request at kernelnewbies.org
>
> You can reach the person managing the list at
>         kernelnewbies-owner at kernelnewbies.org
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Kernelnewbies digest..."
>
>
> Today's Topics:
>
>    1. Re:Re: Why exist coding style issue in mm_types.h (YU Bo)
>    2. Re: Project Idea.. (Mulyadi Santosa)
>    3. Books Regarding Linux Kernel (Anil Nair)
>    4. Re: Books Regarding Linux Kernel (Shiva Shankar)
>    5. Re: Books Regarding Linux Kernel (Kenneth Adam Miller)
>    6. Re: Books Regarding Linux Kernel (sanjeev sharma)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 22 Feb 2016 13:05:29 +0800 (CST)
> From: "YU Bo" <yuzibode at 126.com>
> Subject: Re:Re: Why exist coding style issue in mm_types.h
> To: "Greg KH" <greg at kroah.com>
> Cc: "kernelnewbies at kernelnewbies.org"
>         <kernelnewbies at kernelnewbies.org>
> Message-ID: <5dfbf723.561d.153075e3acb.Coremail.yuzibode at 126.com>
> Content-Type: text/plain; charset="gbk"
>
> Hi,
> At 2016-02-22 02:27:39, "Greg KH" <greg at kroah.com> wrote:
>>On Mon, Feb 22, 2016 at 12:29:54AM +0800, YU Bo wrote:
>>> Hi,
>>>   When  read the source code of mm_types.h, i encounter _coding style_ code
>>> ,such like:
>>> http://lxr.free-electrons.com/source/include/linux/mm_types.h#L346 in comments.
>>> Why not try to fix it? Because it is trival?
>>> Actually, checkpatch.pl reports many errors and warnnings for it.
>>> Only can i fix the coding style issue in staging?
>>
>>Yes, stick to drivers/staging/* only for coding style fixes please.
>
>>
> Thanks a lot!
> -------------- next part --------------
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>
> ------------------------------
>
> Message: 2
> Date: Mon, 22 Feb 2016 12:45:06 +0700
> From: Mulyadi Santosa <mulyadi.santosa at gmail.com>
> Subject: Re: Project Idea..
> To: kernelnewbies <Kernelnewbies at kernelnewbies.org>
> Message-ID:
>         <CAGdaadYaCvUqxDOqax430gDH1OVfJd+xZjvSq_qNX9vWnm-hjw at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> On Mon, Feb 22, 2016 at 12:24 PM, SUNITA <sunitad100 at gmail.com> wrote:
>
>> Respected Sir/Madam,
>> I am trying to study the effect of Scheduler Policies on Energy
>> Consumption of Portable Device.
>>
>> This will be achieved by modifying the current Completely Fair
>> Scheduler by changing the range of nice values from 40 to 100 and
>> adding a new scheduing policy.
>> CFS uses SCHED_RR, SCHED_FCFS, SCHED_OTHER, SCHED_BATCH Policy for
>> scheduling any process.  The idea is to insert a new scheduling policy
>> by modifying the header files.
>>
>> Can this be a good topic to carry out research.I welcome any other
>> idea related Linux Kernel CFS.
>>
>> Regards,
>> SUNIITA
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>
> Hi Suniita
>
> Sounds challenging.
>
> It might be good topic. Just make sure you understand how to measure power
> consumption and prepare various scenario of load simulation to mimic real
> power consumption pattern.
>
>
> --
> regards,
>
> Mulyadi Santosa
> Freelance Linux trainer and consultant
>
> blog: the-hydra.blogspot.com
> training: mulyaditraining.blogspot.com
>
> This email has been sent from a virus-free computer protected by Avast.
> www.avast.com <https://www.avast.com/sig-email>
> <#DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
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>
> ------------------------------
>
> Message: 3
> Date: Mon, 22 Feb 2016 11:26:31 +0530
> From: Anil Nair <anilcoll90 at gmail.com>
> Subject: Books Regarding Linux Kernel
> To: kernelnewbies at kernelnewbies.org
> Message-ID:
>         <CAHkwNTks=fV-dUon2Y7UstJDQXLfSXF=q_XKkfSEiikDbBfmbQ at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> Hi,
>
> Can anyone suggest any good book for understanding the Linux Kernel?
>
> Are these books enough for understanding workings of Linux Kernel?
>
> 1.Linux Kernel in a Nutshell
> 2.Linux Device Drivers, Third Edition
> 3.Linux Kernel Development (3rd Edition)
>
>
> --
> --
> Regards,
> Anil Nair
>
>
>
> ------------------------------
>
> Message: 4
> Date: Mon, 22 Feb 2016 11:30:01 +0530
> From: Shiva Shankar <klshiva4a4 at gmail.com>
> Subject: Re: Books Regarding Linux Kernel
> To: Anil Nair <anilcoll90 at gmail.com>
> Cc: kernelnewbies <kernelnewbies at kernelnewbies.org>
> Message-ID:
>         <CAKe3+gL0FfQkAYCac_rMZHcSQZ=c3aNaD8oP66MmO1MoNP4+BQ at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hi Anil,
> Listed books are enough to start programming.
>
> You can also refer to
> Professional Linux Kernel Architecture
> Book by Wolfgang Mauerer
>
> Thanks
>
>
> On Mon, Feb 22, 2016 at 11:26 AM, Anil Nair <anilcoll90 at gmail.com> wrote:
>
>> Hi,
>>
>> Can anyone suggest any good book for understanding the Linux Kernel?
>>
>> Are these books enough for understanding workings of Linux Kernel?
>>
>> 1.Linux Kernel in a Nutshell
>> 2.Linux Device Drivers, Third Edition
>> 3.Linux Kernel Development (3rd Edition)
>>
>>
>> --
>> --
>> Regards,
>> Anil Nair
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
> -------------- next part --------------
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>
> ------------------------------
>
> Message: 5
> Date: Mon, 22 Feb 2016 01:00:59 -0500
> From: Kenneth Adam Miller <kennethadammiller at gmail.com>
> Subject: Re: Books Regarding Linux Kernel
> To: Anil Nair <anilcoll90 at gmail.com>
> Cc: Kernelnewbies <kernelnewbies at kernelnewbies.org>
> Message-ID:
>         <CAK7rcp9AD7KoQ61tjnT4iw-_dv98XeLZZDzaoq8mkrSfzT44Gw at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Those are the popular three, but the documentation provided by kernel
> authors themselves as well as source code is also expected.
>
> Lastly, semantics of the machine are often a required read. The intel
> manual might be something that belongs on your list, if you want to truly
> understand.
>
> But no book is really enough to completely understand the linux kernel.
> Those just help you get started.
>
> On Mon, Feb 22, 2016 at 12:56 AM, Anil Nair <anilcoll90 at gmail.com> wrote:
>
>> Hi,
>>
>> Can anyone suggest any good book for understanding the Linux Kernel?
>>
>> Are these books enough for understanding workings of Linux Kernel?
>>
>> 1.Linux Kernel in a Nutshell
>> 2.Linux Device Drivers, Third Edition
>> 3.Linux Kernel Development (3rd Edition)
>>
>>
>> --
>> --
>> Regards,
>> Anil Nair
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
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>
> ------------------------------
>
> Message: 6
> Date: Mon, 22 Feb 2016 11:32:05 +0530
> From: sanjeev sharma <sanjeevsharmaengg at gmail.com>
> Subject: Re: Books Regarding Linux Kernel
> To: Shiva Shankar <klshiva4a4 at gmail.com>
> Cc: Anil Nair <anilcoll90 at gmail.com>,   kernelnewbies
>         <kernelnewbies at kernelnewbies.org>
> Message-ID:
>         <CAGUYZuT_jj3eWKwv8=nGkREPFK-5qXTNSXVFGPr01_AMeSR4gw at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hello,
>
> Please don't forget to read Linux Kernel by Robert Love.It is very good for
> beginner.
>
> Regards
> Sanjeev Sharma
>
> On Mon, Feb 22, 2016 at 11:30 AM, Shiva Shankar <klshiva4a4 at gmail.com>
> wrote:
>
>> Hi Anil,
>> Listed books are enough to start programming.
>>
>> You can also refer to
>> Professional Linux Kernel Architecture
>> Book by Wolfgang Mauerer
>>
>> Thanks
>>
>>
>> On Mon, Feb 22, 2016 at 11:26 AM, Anil Nair <anilcoll90 at gmail.com> wrote:
>>
>>> Hi,
>>>
>>> Can anyone suggest any good book for understanding the Linux Kernel?
>>>
>>> Are these books enough for understanding workings of Linux Kernel?
>>>
>>> 1.Linux Kernel in a Nutshell
>>> 2.Linux Device Drivers, Third Edition
>>> 3.Linux Kernel Development (3rd Edition)
>>>
>>>
>>> --
>>> --
>>> Regards,
>>> Anil Nair
>>>
>>> _______________________________________________
>>> Kernelnewbies mailing list
>>> Kernelnewbies at kernelnewbies.org
>>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>>
>>
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>>
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> ------------------------------
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
> End of Kernelnewbies Digest, Vol 63, Issue 37
> *********************************************


From aruna.hewapathirane at gmail.com  Mon Feb 22 11:02:24 2016
From: aruna.hewapathirane at gmail.com (Aruna Hewapathirane)
Date: Mon, 22 Feb 2016 11:02:24 -0500
Subject: Books Regarding Linux Kernel
In-Reply-To: <CAHkwNTks=fV-dUon2Y7UstJDQXLfSXF=q_XKkfSEiikDbBfmbQ@mail.gmail.com>
References: <CAHkwNTks=fV-dUon2Y7UstJDQXLfSXF=q_XKkfSEiikDbBfmbQ@mail.gmail.com>
Message-ID: <CAFSeFg-00n_2LVF9Lf8iKZrMGw=ud802jTkqRV2b3459t4ZLBw@mail.gmail.com>

Hi Anil,

The book 'Linux Programming Interface' by Michael Kerrisk who is the Linux
man-pages maintainer is full of useful examples and the breadth and depth
of its coverage is remarkable.

When it comes to networking there is a book 'Linux Kernel Networking:
Implementation and Theory' by Rami Rosen that is comprehensive and through.

It helps immensely once you understand the 'subsystems' first. This will
help: http://kernelnewbies.org/Documentation/Subsystems

That being said if you truly want to 'understand' the kernel the best way
is to start building your own and the best documentation I have found is
the source itself :)

Good luck !

Aruna



On Mon, Feb 22, 2016 at 12:56 AM, Anil Nair <anilcoll90 at gmail.com> wrote:

> Hi,
>
> Can anyone suggest any good book for understanding the Linux Kernel?
>
> Are these books enough for understanding workings of Linux Kernel?
>
> 1.Linux Kernel in a Nutshell
> 2.Linux Device Drivers, Third Edition
> 3.Linux Kernel Development (3rd Edition)
>
>
> --
> --
> Regards,
> Anil Nair
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
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From greg at kroah.com  Mon Feb 22 11:18:43 2016
From: greg at kroah.com (Greg KH)
Date: Mon, 22 Feb 2016 08:18:43 -0800
Subject: Project Idea..
In-Reply-To: <CAMEb3oqQ3-cx0faqCxJTNkK8A5tjs_ozZ0X6-FycBvdOt2K=KQ@mail.gmail.com>
References: <CAMEb3oqQ3-cx0faqCxJTNkK8A5tjs_ozZ0X6-FycBvdOt2K=KQ@mail.gmail.com>
Message-ID: <20160222161843.GA25683@kroah.com>

On Mon, Feb 22, 2016 at 10:54:54AM +0530, SUNITA wrote:
> Respected Sir/Madam,
> I am trying to study the effect of Scheduler Policies on Energy
> Consumption of Portable Device.

There are lots of people currently working on this, and have been for
many years.  I know of at least 3 complete implementations at the
moment (two of which ship in some Android phones), so I would suggest
working with one of those groups to try to get their code merged into
the Linux kernel.  To create a 4th implementation would seem like a bit
of a redundant effort.

Search the archives of lwn.net for details about this if you are
interested.

good luck!

greg k-h


From john.chludzinski at vivaldi.net  Mon Feb 22 17:02:24 2016
From: john.chludzinski at vivaldi.net (John Chludzinski)
Date: Mon, 22 Feb 2016 17:02:24 -0500
Subject: Books Regarding Linux Kernel
In-Reply-To: <CAGUYZuT_jj3eWKwv8=nGkREPFK-5qXTNSXVFGPr01_AMeSR4gw@mail.gmail.com>
References: <CAHkwNTks=fV-dUon2Y7UstJDQXLfSXF=q_XKkfSEiikDbBfmbQ@mail.gmail.com>
	<CAKe3+gL0FfQkAYCac_rMZHcSQZ=c3aNaD8oP66MmO1MoNP4+BQ@mail.gmail.com>
	<CAGUYZuT_jj3eWKwv8=nGkREPFK-5qXTNSXVFGPr01_AMeSR4gw@mail.gmail.com>
Message-ID: <7fa5f53671c9f4af7aa6b1de963f3102@mail.vivaldi.net>

I'd say it's the best for beginners and intermediate level coders (i.e., 
software engineers).

Robert Love's make the difficult understandable.

---John


On 2016-02-22 01:02, sanjeev sharma wrote:
> Hello,
> 
> Please don't forget to read Linux Kernel by Robert Love.It is very
> good for beginner.
> 
> Regards
> Sanjeev Sharma
> 
> On Mon, Feb 22, 2016 at 11:30 AM, Shiva Shankar <klshiva4a4 at gmail.com>
> wrote:
> 
>> Hi Anil,
>> Listed books are enough to start programming.
>> 
>> You can also refer to
>> 
>> Professional Linux Kernel Architecture Book by Wolfgang Mauerer
>> 
>> Thanks
>> 
>> On Mon, Feb 22, 2016 at 11:26 AM, Anil Nair <anilcoll90 at gmail.com>
>> wrote:
>> 
>>> Hi,
>>> 
>>> Can anyone suggest any good book for understanding the Linux
>>> Kernel?
>>> 
>>> Are these books enough for understanding workings of Linux Kernel?
>>> 
>>> 1.Linux Kernel in a Nutshell
>>> 2.Linux Device Drivers, Third Edition
>>> 3.Linux Kernel Development (3rd Edition)
>>> 
>>> --
>>> --
>>> Regards,
>>> Anil Nair
>>> 
>>> _______________________________________________
>>> Kernelnewbies mailing list
>>> Kernelnewbies at kernelnewbies.org
>>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies [1]
>> 
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies [1]
> 
> 
> 
> Links:
> ------
> [1] http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> 
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies



From narkewoody at gmail.com  Tue Feb 23 09:35:55 2016
From: narkewoody at gmail.com (Woody Wu)
Date: Tue, 23 Feb 2016 22:35:55 +0800
Subject: Porting to an S3C2416 failed with no console message
Message-ID: <CAAsE_ucGBDvC8Jc6X6-=vf-uD6XMOiRQNhPKyaD8_eqAnFdz+w@mail.gmail.com>

Hi,

I am trying to port 3.18 kernel to a S3C2416.  Years ago, a guy helped me
ported a 3.1.0 kernel to the same board, and the guy left and the kernel
got too old. The guy also ported an u-boot as boot loader to load the 3.1.0
kernel.  I had the source code of the ported u-boot and the 3.1.0 linux.

Now, my problem is that my porting of 3.18 seems not working, I did not see
any kernel message printed to the first SoC serial port as I expected. As
long as I can get kernel message printed to the serial, I think I can step
by step finish the whole porting work eventually. But now, there is no
message and I have no other hardware debugging tools and knowledges, I felt
I lost my way totally.

I hope someone can give me some suggestions, clues to help me
understand where to check and what's the possible causes.

Since I found the old porting of the 3.1.0 is quit similar to SMDK2416,
then I started my work from also the SMDK2416 board code in 3.18.
Basically, I defined the machine-code to match that passed from u-boot, and
copied the MACHINE-START definition section with removing of some
not-immediately-needed stuff such as USB, NAND and HMSUI etc. I also
enabled the S3C2410 serial driver and enabled the serial console supporting
for the Samsung SoC. Of course, I had the kernel parameter of
"console=ttySAC0", ttySAC0 is the Linux device name of the first UART port
in the SoC. These are basically what I had done and I guess the SoC serial
part between my board and SMDK2416 should be very similar and the kernel
should at least be able to print it's first message then I should have
chance to fix other differences. But there is no kernel message at all as I
mentioned above.

What should I check for the problem usually? Is there a checking list to go
through? I hope you experts can give me some clues.  Thanks in advance!

Best Regards,
woody


-- 
Life is the only flaw in an otherwise perfect nonexistence
    -- Schopenhauer

woody
public key at http://subkeys.pgp.net:11371 (narkewoody at gmail.com)
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From sunitad100 at gmail.com  Tue Feb 23 11:19:58 2016
From: sunitad100 at gmail.com (SUNITA)
Date: Tue, 23 Feb 2016 21:49:58 +0530
Subject: Project Idea..
In-Reply-To: <20160222161843.GA25683@kroah.com>
References: <CAMEb3oqQ3-cx0faqCxJTNkK8A5tjs_ozZ0X6-FycBvdOt2K=KQ@mail.gmail.com>
	<20160222161843.GA25683@kroah.com>
Message-ID: <CAMEb3oqNBAfnBoKeSoxY2NBenNvW3s+wAm_bZtb45nuELUDc5g@mail.gmail.com>

On 22 Feb 2016 21:48, "Greg KH" <greg at kroah.com> wrote:

> On Mon, Feb 22, 2016 at 10:54:54AM +0530, SUNITA wrote:
> > Respected Sir/Madam,
> > I am trying to study the effect of Scheduler Policies on Energy
> > Consumption of Portable Device.
>
> There are lots of people currently working on this, and have been for
> many years.  I know of at least 3 complete implementations at the
> moment (two of which ship in some Android phones), so I would suggest
> working with one of those groups to try to get their code merged into
> the Linux kernel.  To create a 4th implementation would seem like a bit
> of a redundant effort.
>
> Search the archives of lwn.net for details about this if you are
> interested.
>
> good luck!
>
> greg k-h
>
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From sunitad100 at gmail.com  Tue Feb 23 11:20:33 2016
From: sunitad100 at gmail.com (SUNITA)
Date: Tue, 23 Feb 2016 21:50:33 +0530
Subject: Fwd: Re: Project Idea..
In-Reply-To: <CAMEb3ooOHEUhfLh0Ozzye=Qqs_1Nq9GFQBmK2Oa_f3Ki-dWgcQ@mail.gmail.com>
References: <CAMEb3oqQ3-cx0faqCxJTNkK8A5tjs_ozZ0X6-FycBvdOt2K=KQ@mail.gmail.com>
	<CAGdaadYaCvUqxDOqax430gDH1OVfJd+xZjvSq_qNX9vWnm-hjw@mail.gmail.com>
	<CAMEb3ooOHEUhfLh0Ozzye=Qqs_1Nq9GFQBmK2Oa_f3Ki-dWgcQ@mail.gmail.com>
Message-ID: <CAMEb3ory5uVjdvNAyL6ajaMirE0Aycd4ObYvLhzNvUD5NaEnew@mail.gmail.com>

---------- Forwarded message ----------
From: "SUNITA" <sunitad100 at gmail.com>
Date: 23 Feb 2016 17:23
Subject: Re: Project Idea..
To: "Mulyadi Santosa" <mulyadi.santosa at gmail.com>
Cc:

Dear Mulyadi,

Thank you for your reply.  I m proceeding with the modification in
CFS.  Hope this will be useful research.

Regards,
Sunita

On 2/22/16, Mulyadi Santosa <mulyadi.santosa at gmail.com> wrote:
> On Mon, Feb 22, 2016 at 12:24 PM, SUNITA <sunitad100 at gmail.com> wrote:
>
>> Respected Sir/Madam,
>> I am trying to study the effect of Scheduler Policies on Energy
>> Consumption of Portable Device.
>>
>> This will be achieved by modifying the current Completely Fair
>> Scheduler by changing the range of nice values from 40 to 100 and
>> adding a new scheduing policy.
>> CFS uses SCHED_RR, SCHED_FCFS, SCHED_OTHER, SCHED_BATCH Policy for
>> scheduling any process.  The idea is to insert a new scheduling policy
>> by modifying the header files.
>>
>> Can this be a good topic to carry out research.I welcome any other
>> idea related Linux Kernel CFS.
>>
>> Regards,
>> SUNIITA
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>
> Hi Suniita
>
> Sounds challenging.
>
> It might be good topic. Just make sure you understand how to measure power
> consumption and prepare various scenario of load simulation to mimic real
> power consumption pattern.
>
>
> --
> regards,
>
> Mulyadi Santosa
> Freelance Linux trainer and consultant
>
> blog: the-hydra.blogspot.com
> training: mulyaditraining.blogspot.com
>
> This email has been sent from a virus-free computer protected by Avast.
> www.avast.com <https://www.avast.com/sig-email>
> <#DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>
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From Valdis.Kletnieks at vt.edu  Tue Feb 23 11:38:59 2016
From: Valdis.Kletnieks at vt.edu (Valdis Kletnieks)
Date: Tue, 23 Feb 2016 11:38:59 -0500
Subject: Test e-mail, please ignore...
Message-ID: <6389.1456245539@turing-police.cc.vt.edu>

For some reason, I'm not seeing posts I send to the list.
(Has somebody changed the list config, or is there something more
subtle going on?)


From newell.roger at gmail.com  Tue Feb 23 11:52:57 2016
From: newell.roger at gmail.com (Roger H Newell)
Date: Tue, 23 Feb 2016 13:22:57 -0330
Subject: Test e-mail, please ignore...
In-Reply-To: <6389.1456245539@turing-police.cc.vt.edu>
References: <6389.1456245539@turing-police.cc.vt.edu>
Message-ID: <CAEE9rjZ1QNdWiLmO6vQwcVqXd79csDGv7ngCEGQjULFi_NtC9w@mail.gmail.com>

On Tue, Feb 23, 2016 at 1:08 PM, Valdis Kletnieks
<Valdis.Kletnieks at vt.edu> wrote:
> For some reason, I'm not seeing posts I send to the list.
> (Has somebody changed the list config, or is there something more
> subtle going on?)
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

I think it could be normal. Have you checked the archive to make sure
your emails are really going out to the list ? I had a similar issue
where I wasn't receiving emails from the list that I sent to it but
they are in fact there when I check the archive. Some email software
won't show the message twice because it already exists in your sent
folder as is the case with gmail.


From tapas.sarangi at gmail.com  Tue Feb 23 14:41:50 2016
From: tapas.sarangi at gmail.com (Tapas Sarangi)
Date: Tue, 23 Feb 2016 13:41:50 -0600
Subject: Kernel Panic in FIPS mode
Message-ID: <CAOXsZUf7t2vSq1DOzxd4YhNq=-YMOT6BUqmOtUJOq_cu_hM4bQ@mail.gmail.com>

I am recompiling 3.18.27 on a platform derived from el6. FIPS mode is
enabled by checking the following configs:

CONFIG_CRYPTO_FIPS=y
CONFIG_CRYPTO_TEST=y

Following RH docs, initramfs was regenerated using dracut-fips (el6).
I also generated hmac signed vmlinuz during the compilation.

During boot, kernel panics with the following trace:
kernel line has the arguments, 'fips=1 boot=/dev/sda1'.


"end Kernel Panic - not syncing: Module crc32c_intel signature
verification failed in FIPS mode"

Some additional  info:
It seems under fips mode, initrd runs, './sbin/fips.sh' which then
runs 'modprobe tcrypt'.

I tried running modprobe tcrypt without the fips mode on the same
kernel, but it fails with this message.

FATAL: Error inserting tcrypt
(/lib/modules/3.18.27-1.timbuktu/kernel/crypto/tcrypt.ko.gz): Unknown
symbol in module, or unknown parameter (see dmesg)

Looking at dmesg:

[   31.248054] sha256_ssse3: Using AVX optimized SHA-256 implementation

[   31.308174] sha512_ssse3: Using AVX optimized SHA-512 implementation

[   31.407674] alg: No test for crc32 (crc32-pclmul)

[   31.408410] alg: No test for crc32 (crc32-table)

[   31.409086] alg: hash: Failed to load transform for hmac(crc32): -2

[   31.413155] alg: No test for fips(ansi_cprng) (fips_ansi_cprng)

[   31.440281] tcrypt: one or more tests failed!


Now, one of these messages,

[   31.409086] alg: hash: Failed to load transform for hmac(crc32): -2

comes, most likely from :


linux-3.18.27/crypto/tcrypt.c (L1498)

        case 110:

                ret += tcrypt_test("hmac(crc32)");

                break;


and also from

linux-3.18.27/crypto/testmgr.c

     .alg = "hmac(crc32)",

                .test = alg_test_hash,

                .suite = {

                        .hash = {

                                .vecs = bfin_crc_tv_template,

                                .count = BFIN_CRC_TEST_VECTORS

                       }

                }


Any suggestion on how to solve this problem would be appreciated.
Please let me know if I can provide more info. I am ready to help on
that.


From greg at kroah.com  Tue Feb 23 15:02:02 2016
From: greg at kroah.com (Greg KH)
Date: Tue, 23 Feb 2016 12:02:02 -0800
Subject: Kernel Panic in FIPS mode
In-Reply-To: <CAOXsZUf7t2vSq1DOzxd4YhNq=-YMOT6BUqmOtUJOq_cu_hM4bQ@mail.gmail.com>
References: <CAOXsZUf7t2vSq1DOzxd4YhNq=-YMOT6BUqmOtUJOq_cu_hM4bQ@mail.gmail.com>
Message-ID: <20160223200202.GA26480@kroah.com>

On Tue, Feb 23, 2016 at 01:41:50PM -0600, Tapas Sarangi wrote:
> I am recompiling 3.18.27 on a platform derived from el6. FIPS mode is
> enabled by checking the following configs:
> 
> CONFIG_CRYPTO_FIPS=y
> CONFIG_CRYPTO_TEST=y

<snip>

If you are using a RHEL system, you need to contact Red Hat for support
as that is what you are paying for.  Their kernel is a very "odd" one.

Also note that 3.18 is very old and obsolete as well, please use a
"modern" kernel release, the community can't support old kernels like
that.

best of luck,

greg k-h


From kirotawa at gmail.com  Tue Feb 23 15:02:37 2016
From: kirotawa at gmail.com (Leo Silva (a.k.a kirotawa))
Date: Tue, 23 Feb 2016 17:02:37 -0300
Subject: Kernel Panic in FIPS mode
In-Reply-To: <CAOXsZUf7t2vSq1DOzxd4YhNq=-YMOT6BUqmOtUJOq_cu_hM4bQ@mail.gmail.com>
References: <CAOXsZUf7t2vSq1DOzxd4YhNq=-YMOT6BUqmOtUJOq_cu_hM4bQ@mail.gmail.com>
Message-ID: <CA+KS1kbmna4tt9kYPc_xHKFp9sEgBEGDBn-uEN87fjcAB9K-fg@mail.gmail.com>

If it's a kernel provide by a company, such as RHEL or SUSE, I'd recommend
to ask for them support/bugzilla.

Regarding FIPS/fipsmode, it's a kind of certification that is done by these
company with focus on specific hardware and Kernels, if just a bit is
different on a crypto algorithm it'll probably fail, since test
certification, fips, was not done using this 'new algorithm' as base.

[]'s

On Tue, Feb 23, 2016 at 4:41 PM, Tapas Sarangi <tapas.sarangi at gmail.com>
wrote:

> I am recompiling 3.18.27 on a platform derived from el6. FIPS mode is
> enabled by checking the following configs:
>
> CONFIG_CRYPTO_FIPS=y
> CONFIG_CRYPTO_TEST=y
>
> Following RH docs, initramfs was regenerated using dracut-fips (el6).
> I also generated hmac signed vmlinuz during the compilation.
>
> During boot, kernel panics with the following trace:
> kernel line has the arguments, 'fips=1 boot=/dev/sda1'.
>
>
> "end Kernel Panic - not syncing: Module crc32c_intel signature
> verification failed in FIPS mode"
>
> Some additional  info:
> It seems under fips mode, initrd runs, './sbin/fips.sh' which then
> runs 'modprobe tcrypt'.
>
> I tried running modprobe tcrypt without the fips mode on the same
> kernel, but it fails with this message.
>
> FATAL: Error inserting tcrypt
> (/lib/modules/3.18.27-1.timbuktu/kernel/crypto/tcrypt.ko.gz): Unknown
> symbol in module, or unknown parameter (see dmesg)
>
> Looking at dmesg:
>
> [   31.248054] sha256_ssse3: Using AVX optimized SHA-256 implementation
>
> [   31.308174] sha512_ssse3: Using AVX optimized SHA-512 implementation
>
> [   31.407674] alg: No test for crc32 (crc32-pclmul)
>
> [   31.408410] alg: No test for crc32 (crc32-table)
>
> [   31.409086] alg: hash: Failed to load transform for hmac(crc32): -2
>
> [   31.413155] alg: No test for fips(ansi_cprng) (fips_ansi_cprng)
>
> [   31.440281] tcrypt: one or more tests failed!
>
>
> Now, one of these messages,
>
> [   31.409086] alg: hash: Failed to load transform for hmac(crc32): -2
>
> comes, most likely from :
>
>
> linux-3.18.27/crypto/tcrypt.c (L1498)
>
>         case 110:
>
>                 ret += tcrypt_test("hmac(crc32)");
>
>                 break;
>
>
> and also from
>
> linux-3.18.27/crypto/testmgr.c
>
>      .alg = "hmac(crc32)",
>
>                 .test = alg_test_hash,
>
>                 .suite = {
>
>                         .hash = {
>
>                                 .vecs = bfin_crc_tv_template,
>
>                                 .count = BFIN_CRC_TEST_VECTORS
>
>                        }
>
>                 }
>
>
> Any suggestion on how to solve this problem would be appreciated.
> Please let me know if I can provide more info. I am ready to help on
> that.
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>



-- 

----------------------------------------------
Le?nidas S. Barbosa (Kirotawa)
blog: corecode.wordpress.com
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From tapas.sarangi at gmail.com  Tue Feb 23 15:41:37 2016
From: tapas.sarangi at gmail.com (Tapas Sarangi)
Date: Tue, 23 Feb 2016 14:41:37 -0600
Subject: Kernel Panic in FIPS mode
In-Reply-To: <20160223200202.GA26480@kroah.com>
References: <CAOXsZUf7t2vSq1DOzxd4YhNq=-YMOT6BUqmOtUJOq_cu_hM4bQ@mail.gmail.com>
	<20160223200202.GA26480@kroah.com>
Message-ID: <703D0F9C-C5DF-45DE-88AC-7C46C4499282@gmail.com>

Thanks for the reply.
 I am using and compiling kernel from kernel.org. I believe 3.18.27 with patches is as new as in January of this year. 

 

Sent from my iPhone

> On Feb 23, 2016, at 2:02 PM, Greg KH <greg at kroah.com> wrote:
> 
>> On Tue, Feb 23, 2016 at 01:41:50PM -0600, Tapas Sarangi wrote:
>> I am recompiling 3.18.27 on a platform derived from el6. FIPS mode is
>> enabled by checking the following configs:
>> 
>> CONFIG_CRYPTO_FIPS=y
>> CONFIG_CRYPTO_TEST=y
> 
> <snip>
> 
> If you are using a RHEL system, you need to contact Red Hat for support
> as that is what you are paying for.  Their kernel is a very "odd" one.
> 
> Also note that 3.18 is very old and obsolete as well, please use a
> "modern" kernel release, the community can't support old kernels like
> that.
> 
> best of luck,
> 
> greg k-h


From greg at kroah.com  Tue Feb 23 16:14:38 2016
From: greg at kroah.com (Greg KH)
Date: Tue, 23 Feb 2016 13:14:38 -0800
Subject: Kernel Panic in FIPS mode
In-Reply-To: <703D0F9C-C5DF-45DE-88AC-7C46C4499282@gmail.com>
References: <CAOXsZUf7t2vSq1DOzxd4YhNq=-YMOT6BUqmOtUJOq_cu_hM4bQ@mail.gmail.com>
	<20160223200202.GA26480@kroah.com>
	<703D0F9C-C5DF-45DE-88AC-7C46C4499282@gmail.com>
Message-ID: <20160223211438.GA27854@kroah.com>

On Tue, Feb 23, 2016 at 02:41:37PM -0600, Tapas Sarangi wrote:
> Thanks for the reply.
>  I am using and compiling kernel from kernel.org. I believe 3.18.27
> with patches is as new as in January of this year. 

The 3.18 kernel was released in December of 2014, the .y patches on the
end of that release are for people who for some reason or another are
stuck with that kernel release, and are part of the longterm releases.

The overall kernel is over a year old, please upgrade.

greg k-h


From tapas.sarangi at gmail.com  Tue Feb 23 18:01:02 2016
From: tapas.sarangi at gmail.com (Tapas Sarangi)
Date: Tue, 23 Feb 2016 17:01:02 -0600
Subject: Kernel Panic in FIPS mode
In-Reply-To: <20160223211438.GA27854@kroah.com>
References: <CAOXsZUf7t2vSq1DOzxd4YhNq=-YMOT6BUqmOtUJOq_cu_hM4bQ@mail.gmail.com>
	<20160223200202.GA26480@kroah.com>
	<703D0F9C-C5DF-45DE-88AC-7C46C4499282@gmail.com>
	<20160223211438.GA27854@kroah.com>
Message-ID: <CAOXsZUdamP_Ej7TxGqje_BEN7=FCoYZGrikH73TadjT4YY3X=Q@mail.gmail.com>

Thanks. I understand your point, but I am one of those people who
simply can't do an upgrade to the LTS kernel. Again, I think this
doesn't necessarily answer my question about FIPS and kernel panic.

An additional note, older kernels (2.6.x) and its RH derivatives,
works fine when started under FIPS mode.

I am sure I am missing some basics when turning the OS to run under
FIPS mode, which is why this email to the experts :-)

On Tue, Feb 23, 2016 at 3:14 PM, Greg KH <greg at kroah.com> wrote:
> On Tue, Feb 23, 2016 at 02:41:37PM -0600, Tapas Sarangi wrote:
>> Thanks for the reply.
>>  I am using and compiling kernel from kernel.org. I believe 3.18.27
>> with patches is as new as in January of this year.
>
> The 3.18 kernel was released in December of 2014, the .y patches on the
> end of that release are for people who for some reason or another are
> stuck with that kernel release, and are part of the longterm releases.
>
> The overall kernel is over a year old, please upgrade.
>
> greg k-h


From tapas.sarangi at gmail.com  Tue Feb 23 18:02:56 2016
From: tapas.sarangi at gmail.com (Tapas Sarangi)
Date: Tue, 23 Feb 2016 17:02:56 -0600
Subject: Kernel Panic in FIPS mode
In-Reply-To: <CA+KS1kbmna4tt9kYPc_xHKFp9sEgBEGDBn-uEN87fjcAB9K-fg@mail.gmail.com>
References: <CAOXsZUf7t2vSq1DOzxd4YhNq=-YMOT6BUqmOtUJOq_cu_hM4bQ@mail.gmail.com>
	<CA+KS1kbmna4tt9kYPc_xHKFp9sEgBEGDBn-uEN87fjcAB9K-fg@mail.gmail.com>
Message-ID: <CAOXsZUcSkya_3zAPaS0wcEE4peKo=ifZe9F5zZjgSd_OCAayCQ@mail.gmail.com>

Thanks. I am taking the kernel from kernel.org not the one provided by
Red Hat or any other OS. AFAIU, certification or module signatures are
done during kernel compilation (by turning on MODULE_SIG*).

On Tue, Feb 23, 2016 at 2:02 PM, Leo Silva (a.k.a kirotawa)
<kirotawa at gmail.com> wrote:
> If it's a kernel provide by a company, such as RHEL or SUSE, I'd recommend
> to ask for them support/bugzilla.
>
> Regarding FIPS/fipsmode, it's a kind of certification that is done by these
> company with focus on specific hardware and Kernels, if just a bit is
> different on a crypto algorithm it'll probably fail, since test
> certification, fips, was not done using this 'new algorithm' as base.
>
> []'s
>
> On Tue, Feb 23, 2016 at 4:41 PM, Tapas Sarangi <tapas.sarangi at gmail.com>
> wrote:
>>
>> I am recompiling 3.18.27 on a platform derived from el6. FIPS mode is
>> enabled by checking the following configs:
>>
>> CONFIG_CRYPTO_FIPS=y
>> CONFIG_CRYPTO_TEST=y
>>
>> Following RH docs, initramfs was regenerated using dracut-fips (el6).
>> I also generated hmac signed vmlinuz during the compilation.
>>
>> During boot, kernel panics with the following trace:
>> kernel line has the arguments, 'fips=1 boot=/dev/sda1'.
>>
>>
>> "end Kernel Panic - not syncing: Module crc32c_intel signature
>> verification failed in FIPS mode"
>>
>> Some additional  info:
>> It seems under fips mode, initrd runs, './sbin/fips.sh' which then
>> runs 'modprobe tcrypt'.
>>
>> I tried running modprobe tcrypt without the fips mode on the same
>> kernel, but it fails with this message.
>>
>> FATAL: Error inserting tcrypt
>> (/lib/modules/3.18.27-1.timbuktu/kernel/crypto/tcrypt.ko.gz): Unknown
>> symbol in module, or unknown parameter (see dmesg)
>>
>> Looking at dmesg:
>>
>> [   31.248054] sha256_ssse3: Using AVX optimized SHA-256 implementation
>>
>> [   31.308174] sha512_ssse3: Using AVX optimized SHA-512 implementation
>>
>> [   31.407674] alg: No test for crc32 (crc32-pclmul)
>>
>> [   31.408410] alg: No test for crc32 (crc32-table)
>>
>> [   31.409086] alg: hash: Failed to load transform for hmac(crc32): -2
>>
>> [   31.413155] alg: No test for fips(ansi_cprng) (fips_ansi_cprng)
>>
>> [   31.440281] tcrypt: one or more tests failed!
>>
>>
>> Now, one of these messages,
>>
>> [   31.409086] alg: hash: Failed to load transform for hmac(crc32): -2
>>
>> comes, most likely from :
>>
>>
>> linux-3.18.27/crypto/tcrypt.c (L1498)
>>
>>         case 110:
>>
>>                 ret += tcrypt_test("hmac(crc32)");
>>
>>                 break;
>>
>>
>> and also from
>>
>> linux-3.18.27/crypto/testmgr.c
>>
>>      .alg = "hmac(crc32)",
>>
>>                 .test = alg_test_hash,
>>
>>                 .suite = {
>>
>>                         .hash = {
>>
>>                                 .vecs = bfin_crc_tv_template,
>>
>>                                 .count = BFIN_CRC_TEST_VECTORS
>>
>>                        }
>>
>>                 }
>>
>>
>> Any suggestion on how to solve this problem would be appreciated.
>> Please let me know if I can provide more info. I am ready to help on
>> that.
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
>
>
> --
>
> ----------------------------------------------
> Le?nidas S. Barbosa (Kirotawa)
> blog: corecode.wordpress.com


From rolland.santimano at gmail.com  Tue Feb 23 23:11:59 2016
From: rolland.santimano at gmail.com (Rolland Santimano)
Date: Wed, 24 Feb 2016 09:41:59 +0530
Subject: Partial (?) kernel crash dump ?
Message-ID: <CAJ1F5Mus24azqPOZxJZJCWNXiuKv8jM8VBB0TkE+yebUyUS64A@mail.gmail.com>

I'm trying to save a crashdump on a DellFC630 with 128G of RAM,
running Ubuntu 14.10, kernel 3.16.0-23-generic; used to host a bunch
of KVM-style VMs.

Since saving the full dump is taking forever & a day, I'm looking to
save a partial dump -- maybe a few addr space regions only from the
kernel VAS.

Is this even possible ? Any other options ? Or am I missing something here ?

-- 
Rolland


From navych at 126.com  Tue Feb 23 23:57:42 2016
From: navych at 126.com (Navy Cheng)
Date: Wed, 24 Feb 2016 12:57:42 +0800
Subject: Is there a bug in dgnc.ko?
Message-ID: <20160224045742.GA24012@debian>

Hi,

My kernel version is v4.4, and I have built drivers/staging/dgnc/dgnc.ko.
I change to *dir*/drivers/staging/dgnc and do like this:

    sudo insmod ./dgnc.ko
    sudo lsmod | grep dgnc
    sudo rmmod ./dgnc
    sudo insmod ./dgnc.ko

After I re-insmod the dgnc module, my laptop is breakdown.

My OS is debian 8.0. Is there a bug in dgnc.ko or something wrong with my
OS or kernel. If there is a bug, How can I find it?

Thanks.



From Valdis.Kletnieks at vt.edu  Wed Feb 24 00:37:40 2016
From: Valdis.Kletnieks at vt.edu (Valdis.Kletnieks at vt.edu)
Date: Wed, 24 Feb 2016 00:37:40 -0500
Subject: Is there a bug in dgnc.ko?
In-Reply-To: <20160224045742.GA24012@debian>
References: <20160224045742.GA24012@debian>
Message-ID: <11119.1456292260@turing-police.cc.vt.edu>

On Wed, 24 Feb 2016 12:57:42 +0800, Navy Cheng said:
> Hi,
>
> My kernel version is v4.4, and I have built drivers/staging/dgnc/dgnc.ko.
> I change to *dir*/drivers/staging/dgnc and do like this:
>
>     sudo insmod ./dgnc.ko

What output, if any, did this generate?

>     sudo lsmod | grep dgnc

Again, what messages?

>     sudo rmmod ./dgnc

Again, what happened?

>     sudo insmod ./dgnc.ko

And here?

> After I re-insmod the dgnc module, my laptop is breakdown.

What does "breakdown" mean?  Did it hang entirely? Did you get a message
in your dmesg output and/or on the console?  Other?

> My OS is debian 8.0. Is there a bug in dgnc.ko or something wrong with my
> OS or kernel. If there is a bug, How can I find it?

Start by providing enough info to see if there's a bug.
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From greg at kroah.com  Wed Feb 24 00:43:56 2016
From: greg at kroah.com (Greg KH)
Date: Tue, 23 Feb 2016 21:43:56 -0800
Subject: Is there a bug in dgnc.ko?
In-Reply-To: <20160224045742.GA24012@debian>
References: <20160224045742.GA24012@debian>
Message-ID: <20160224054356.GA1138@kroah.com>

On Wed, Feb 24, 2016 at 12:57:42PM +0800, Navy Cheng wrote:
> Hi,
> 
> My kernel version is v4.4, and I have built drivers/staging/dgnc/dgnc.ko.
> I change to *dir*/drivers/staging/dgnc and do like this:
> 
>     sudo insmod ./dgnc.ko

Do you have the hardware that this driver controls?

>     sudo lsmod | grep dgnc

Does that show anything?

>     sudo rmmod ./dgnc
>     sudo insmod ./dgnc.ko
> 
> After I re-insmod the dgnc module, my laptop is breakdown.

Then there's a bug to fix in the driver, it must not clean up everything
properly.  Based on a quick read of it, there is lots of things that
need to be fixed in it, that's why it is in staging.  If you are
interested, I would suggest fixing this issue would be a great start.

good luck!

greg k-h


From ranshalit at gmail.com  Wed Feb 24 02:36:54 2016
From: ranshalit at gmail.com (Ran Shalit)
Date: Wed, 24 Feb 2016 09:36:54 +0200
Subject: user rsyslog/syslog
Message-ID: <CAJ2oMhK3Q5sNno0tgMoifXL5LP-iDYveKajWxgQfHCO0y_96vw@mail.gmail.com>

Hello,

I am trying to write to rsyslog from application.
With openlog(..., LOG_USER), it works fine and I find the log in
/var/log/user.log (it is defines in /etc/rsyslog.d/50-defaults.conf )
But we need to enable different applications to have each its own log file.
I tried to use LOG_LOCAL0 instead and configured it in
/etc/rsyslog.d/50-defaults.conf the same way as user:

local0.* action
{
  type="omfile"
 FILE="/var/log/local0.log"
 FileOwner="root"
 FileGroup="adm"

}

I then did
1. /etc/init.d/rsyslog stop
2. /etc/init.d/rsyslog start
I see no warnings or errors, and I started the application trying to
write to LOG_LOCAL0, But there is no new file created, no logs.

Is there any idea whatws wrong, or how I can achieve this multi user's logs ?

Thank you,
Ran


From ruben at mrbrklyn.com  Wed Feb 24 02:54:45 2016
From: ruben at mrbrklyn.com (Ruben Safir)
Date: Wed, 24 Feb 2016 02:54:45 -0500
Subject: user rsyslog/syslog
In-Reply-To: <CAJ2oMhK3Q5sNno0tgMoifXL5LP-iDYveKajWxgQfHCO0y_96vw@mail.gmail.com>
References: <CAJ2oMhK3Q5sNno0tgMoifXL5LP-iDYveKajWxgQfHCO0y_96vw@mail.gmail.com>
Message-ID: <56CD61C5.5060000@mrbrklyn.com>

On 02/24/2016 02:36 AM, Ran Shalit wrote:
> Hello,

systemd?

> 
> I am trying to write to rsyslog from application.
> With openlog(..., LOG_USER), it works fine and I find the log in
> /var/log/user.log (it is defines in /etc/rsyslog.d/50-defaults.conf )
> But we need to enable different applications to have each its own log file.
> I tried to use LOG_LOCAL0 instead and configured it in
> /etc/rsyslog.d/50-defaults.conf the same way as user:
> 
> local0.* action
> {
>   type="omfile"
>  FILE="/var/log/local0.log"
>  FileOwner="root"
>  FileGroup="adm"
> 
> }
> 
> I then did
> 1. /etc/init.d/rsyslog stop
> 2. /etc/init.d/rsyslog start
> I see no warnings or errors, and I started the application trying to
> write to LOG_LOCAL0, But there is no new file created, no logs.
> 
> Is there any idea whatws wrong, or how I can achieve this multi user's logs ?
> 
> Thank you,
> Ran
> 
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> 


-- 
So many immigrant groups have swept through our town
that Brooklyn, like Atlantis, reaches mythological
proportions in the mind of the world - RI Safir 1998
http://www.mrbrklyn.com

DRM is THEFT - We are the STAKEHOLDERS - RI Safir 2002
http://www.nylxs.com - Leadership Development in Free Software
http://www2.mrbrklyn.com/resources - Unpublished Archive
http://www.coinhangout.com - coins!
http://www.brooklyn-living.com

Being so tracked is for FARM ANIMALS and and extermination camps,
but incompatible with living as a free human being. -RI Safir 2013


From Valdis.Kletnieks at vt.edu  Wed Feb 24 03:17:33 2016
From: Valdis.Kletnieks at vt.edu (Valdis.Kletnieks at vt.edu)
Date: Wed, 24 Feb 2016 03:17:33 -0500
Subject: user rsyslog/syslog
In-Reply-To: <CAJ2oMhK3Q5sNno0tgMoifXL5LP-iDYveKajWxgQfHCO0y_96vw@mail.gmail.com>
References: <CAJ2oMhK3Q5sNno0tgMoifXL5LP-iDYveKajWxgQfHCO0y_96vw@mail.gmail.com>
Message-ID: <22877.1456301853@turing-police.cc.vt.edu>

On Wed, 24 Feb 2016 09:36:54 +0200, Ran Shalit said:

> I am trying to write to rsyslog from application.
> With openlog(..., LOG_USER), it works fine and I find the log in
> /var/log/user.log (it is defines in /etc/rsyslog.d/50-defaults.conf )
> But we need to enable different applications to have each its own log file.
> I tried to use LOG_LOCAL0 instead and configured it in
> /etc/rsyslog.d/50-defaults.conf the same way as user:
>
> local0.* action
> {
>   type="omfile"
>  FILE="/var/log/local0.log"
>  FileOwner="root"
>  FileGroup="adm"
>
> }
>
> I then did
> 1. /etc/init.d/rsyslog stop
> 2. /etc/init.d/rsyslog start
> I see no warnings or errors, and I started the application trying to
> write to LOG_LOCAL0, But there is no new file created, no logs.
>
> Is there any idea whatws wrong, or how I can achieve this multi user's logs ?

Not really a kernel issue, is it?  But anyhow....

First thing to do is to make sure your code checks the return code
from openlog().

The next thing to check is that your application is actually trying to
log to LOCAL0.  Using the debugging tool of your choice, ensure that control
flow reaches the syslog() statement. Make sure that it's using LOCAL0.

Define an action for *.* dumping to /var/log/everything.log - does your
message show up in there?

In other words, all the usual userspace debugging.. start at the beginning
and trace through the flow.

And since rsyslog allows regex matching, maybe you should be letting all the
applications continue logging to LOG_USER, and then use filters
of the form 'programname startswith app1', 'programname startswith app2',
and so on to select based on the program name.

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From mulyadi.santosa at gmail.com  Wed Feb 24 04:12:02 2016
From: mulyadi.santosa at gmail.com (Mulyadi Santosa)
Date: Wed, 24 Feb 2016 16:12:02 +0700
Subject: Partial (?) kernel crash dump ?
In-Reply-To: <CAJ1F5Mus24azqPOZxJZJCWNXiuKv8jM8VBB0TkE+yebUyUS64A@mail.gmail.com>
References: <CAJ1F5Mus24azqPOZxJZJCWNXiuKv8jM8VBB0TkE+yebUyUS64A@mail.gmail.com>
Message-ID: <CAGdaadZM+MT=esALvhSLD73pRn8jjofWG04tP7uZFjyDU03Gjw@mail.gmail.com>

On Wed, Feb 24, 2016 at 11:11 AM, Rolland Santimano <
rolland.santimano at gmail.com> wrote:

> I'm trying to save a crashdump on a DellFC630 with 128G of RAM,
> running Ubuntu 14.10, kernel 3.16.0-23-generic; used to host a bunch
> of KVM-style VMs.
>
> Since saving the full dump is taking forever & a day, I'm looking to
> save a partial dump -- maybe a few addr space regions only from the
> kernel VAS.
>
> Is this even possible ? Any other options ? Or am I missing something here
> ?
>
> --
> Rolland
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>

try to read this:
http://events.linuxfoundation.org/sites/events/files/slides/slide_final_0.pdf

It might be not what you're looking for, but IMHO worth to read


-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

This email has been sent from a virus-free computer protected by Avast.
www.avast.com <https://www.avast.com/sig-email>
<#DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
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From navych at 126.com  Wed Feb 24 06:57:01 2016
From: navych at 126.com (Navy Cheng)
Date: Wed, 24 Feb 2016 19:57:01 +0800
Subject: Is there a bug in dgnc.ko?
In-Reply-To: <20160224054356.GA1138@kroah.com>
References: <20160224045742.GA24012@debian> <20160224054356.GA1138@kroah.com>
Message-ID: <20160224115701.GB1998@debian>

On Tue, Feb 23, 2016 at 09:43:56PM -0800, Greg KH wrote:
> On Wed, Feb 24, 2016 at 12:57:42PM +0800, Navy Cheng wrote:
> > Hi,
> > 
> > My kernel version is v4.4, and I have built drivers/staging/dgnc/dgnc.ko.
> > I change to *dir*/drivers/staging/dgnc and do like this:
> > 
> >     sudo insmod ./dgnc.ko
> 
> Do you have the hardware that this driver controls?

I'm not sure. My laptop is Dell Inspiron 14R - 5437 and I don't know if
there is the right hardware. I often don't know about what a driver is used
for in drivers/staging/. Is there any good way to know the function of a
driver or module?

> 
> >     sudo lsmod | grep dgnc
> 
> Does that show anything?

Output: dgnc                   65536  0

> >     sudo rmmod ./dgnc
> >     sudo insmod ./dgnc.ko
> > 
> > After I re-insmod the dgnc module, my laptop is breakdown.
> 
> Then there's a bug to fix in the driver, it must not clean up everything
> properly.  Based on a quick read of it, there is lots of things that
> need to be fixed in it, that's why it is in staging.  If you are
> interested, I would suggest fixing this issue would be a great start.

I'm very glad to get your advice to fix this issue. As a kernelnewbies, I
have sent two patches about code cleaning to you, and they are merged to
the kernel tree. I realy interested to fix this bug to improve my
understanding of the kerenl.

Thank you.



From sudipm.mukherjee at gmail.com  Wed Feb 24 07:03:11 2016
From: sudipm.mukherjee at gmail.com (Sudip Mukherjee)
Date: Wed, 24 Feb 2016 17:33:11 +0530
Subject: Is there a bug in dgnc.ko?
In-Reply-To: <20160224115701.GB1998@debian>
References: <20160224045742.GA24012@debian> <20160224054356.GA1138@kroah.com>
	<20160224115701.GB1998@debian>
Message-ID: <CADVatmM3GYxire8KEYuBj3DmVN+=aqzYzgCMOrGkXW2wn3fvGg@mail.gmail.com>

On Wed, Feb 24, 2016 at 5:27 PM, Navy Cheng <navych at 126.com> wrote:
> On Tue, Feb 23, 2016 at 09:43:56PM -0800, Greg KH wrote:
>> On Wed, Feb 24, 2016 at 12:57:42PM +0800, Navy Cheng wrote:
>> > Hi,
>> >
>> > My kernel version is v4.4, and I have built drivers/staging/dgnc/dgnc.ko.
>> > I change to *dir*/drivers/staging/dgnc and do like this:
>> >
>> >     sudo insmod ./dgnc.ko
>>
>> Do you have the hardware that this driver controls?
>
> I'm not sure. My laptop is Dell Inspiron 14R - 5437 and I don't know if
> there is the right hardware. I often don't know about what a driver is used
> for in drivers/staging/. Is there any good way to know the function of a
> driver or module?
>
>>
>> >     sudo lsmod | grep dgnc
>>
>> Does that show anything?
>
> Output: dgnc                   65536  0
>
>> >     sudo rmmod ./dgnc

what did dmesg showed after you did rmmod?

regards
sudip


From navych at 126.com  Wed Feb 24 06:36:21 2016
From: navych at 126.com (Navy Cheng)
Date: Wed, 24 Feb 2016 19:36:21 +0800
Subject: Is there a bug in dgnc.ko?
In-Reply-To: <11119.1456292260@turing-police.cc.vt.edu>
References: <20160224045742.GA24012@debian>
	<11119.1456292260@turing-police.cc.vt.edu>
Message-ID: <20160224113621.GA1998@debian>

On Wed, Feb 24, 2016 at 12:37:40AM -0500, Valdis.Kletnieks at vt.edu wrote:
> On Wed, 24 Feb 2016 12:57:42 +0800, Navy Cheng said:
> > Hi,
> >
> > My kernel version is v4.4, and I have built drivers/staging/dgnc/dgnc.ko.
> > I change to *dir*/drivers/staging/dgnc and do like this:
> >
> >     sudo insmod ./dgnc.ko
> 
> What output, if any, did this generate?

No output. I use *dmesg* to find more information:

[  572.915977] dgnc: module is from the staging directory, the quality is
   	       unknown, you have been warned.

> >     sudo lsmod | grep dgnc
> 
> Again, what messages?

Output:
	dgnc                   65536  0

> >     sudo rmmod ./dgnc
> 
> Again, what happened?

No output. After *dmesg*, no more info in the ring buffer.

> >     sudo insmod ./dgnc.ko
> 
> And here?

No output. 


> > After I re-insmod the dgnc module, my laptop is breakdown.
>
> What does "breakdown" mean?  Did it hang entirely? Did you get a message
> in your dmesg output and/or on the console?  Other?

The GUI stop work and any key in my laptop is not work. The *Caps Lock lamp*
in the keyboard is flashing.

> > My OS is debian 8.0. Is there a bug in dgnc.ko or something wrong with my
> > OS or kernel. If there is a bug, How can I find it?
> 
> Start by providing enough info to see if there's a bug.



> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies




From priyaranjan45678 at gmail.com  Wed Feb 24 07:14:17 2016
From: priyaranjan45678 at gmail.com (priyaranjan)
Date: Wed, 24 Feb 2016 17:44:17 +0530
Subject: Does Linux kernel disables any Interrupts while going into IRQ
	handler?
Message-ID: <CAE_iR+jt9jXw0+nFnGH8JkSbRjpc-v8gnt2qkuAROAaTS=rDSA@mail.gmail.com>

When an Interrupt occurs most device drivers creates a critical section
using spin_lock_irqsave or spin_lock_irq which disables the interrupt.

In such a case the Interrupts are disabled by the IRQ handler. My question
is whether Linux kernel disables any interrupts just when the IRQ handler
executes or it just wait for the IRQ handler programmer to disable the IRQ
in whatever way?

My understanding is that Russel King has implemented IRQ_DISABLED, If this
flag is set then only the IRQ that has occurred is disabled lately however
enabled automatically by Kernel after IRQ handler finishes. Is that
correct? This also happens in delayed manner.Can anyone explain me how
exactly the IRQ disabling is delayed?

>From free-electrons link
<http://free-electrons.com/kerneldoc/latest/DocBook/genericirq/Highlevel_IRQ_flow_handlers.html>,
what I read is :-

*The interrupt is kept enabled and is masked in the flow handler when an
interrupt event happens*. This prevents losing edge interrupts on hardware
which does not store an edge interrupt event while the interrupt is
disabled at the hardware level.

Can anyone please explain the bold line here?

Regards,

Priyaranjan
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From ranshalit at gmail.com  Wed Feb 24 07:20:23 2016
From: ranshalit at gmail.com (Ran Shalit)
Date: Wed, 24 Feb 2016 14:20:23 +0200
Subject: user rsyslog/syslog
In-Reply-To: <22877.1456301853@turing-police.cc.vt.edu>
References: <CAJ2oMhK3Q5sNno0tgMoifXL5LP-iDYveKajWxgQfHCO0y_96vw@mail.gmail.com>
	<22877.1456301853@turing-police.cc.vt.edu>
Message-ID: <CAJ2oMhJOdRuneZ+QPvWdH_Rc7XMcPrm1ydDJyNRfSA5oc+fKXA@mail.gmail.com>

On Wed, Feb 24, 2016 at 10:17 AM,  <Valdis.Kletnieks at vt.edu> wrote:
> On Wed, 24 Feb 2016 09:36:54 +0200, Ran Shalit said:
>
>> I am trying to write to rsyslog from application.
>> With openlog(..., LOG_USER), it works fine and I find the log in
>> /var/log/user.log (it is defines in /etc/rsyslog.d/50-defaults.conf )
>> But we need to enable different applications to have each its own log file.
>> I tried to use LOG_LOCAL0 instead and configured it in
>> /etc/rsyslog.d/50-defaults.conf the same way as user:
>>
>> local0.* action
>> {
>>   type="omfile"
>>  FILE="/var/log/local0.log"
>>  FileOwner="root"
>>  FileGroup="adm"
>>
>> }
>>
>> I then did
>> 1. /etc/init.d/rsyslog stop
>> 2. /etc/init.d/rsyslog start
>> I see no warnings or errors, and I started the application trying to
>> write to LOG_LOCAL0, But there is no new file created, no logs.
>>
>> Is there any idea whatws wrong, or how I can achieve this multi user's logs ?
>
> Not really a kernel issue, is it?  But anyhow....
>
> First thing to do is to make sure your code checks the return code
> from openlog().
>
> The next thing to check is that your application is actually trying to
> log to LOCAL0.  Using the debugging tool of your choice, ensure that control
> flow reaches the syslog() statement. Make sure that it's using LOCAL0.
>
> Define an action for *.* dumping to /var/log/everything.log - does your
> message show up in there?
>
> In other words, all the usual userspace debugging.. start at the beginning
> and trace through the flow.
>
> And since rsyslog allows regex matching, maybe you should be letting all the
> applications continue logging to LOG_USER, and then use filters
> of the form 'programname startswith app1', 'programname startswith app2',
> and so on to select based on the program name.
>
Hi Vladis,

Thanks a lot.
I see that openlog has not retuen value, and it seems that only
openlog get the LOG_USER (or LOG_LOCAL0) arguments.
the other functions such as syslog does not use it at all, for example:

openlog("Logs", "", LOG_USER);
syslog(LOG_INFO, "Start logging");
closelog();

Anyway, on debugging I seet that these routines are called, but
nothing gets into the expected localX files. It only works with the
USER file.

Maybe the last suggestion will be the most practical if this issue
can't be resolved, which means that I will use one file for all logs,
in which each line will have its own tag string according to the
application.

Thanks,
Ran


From narkewoody at gmail.com  Wed Feb 24 09:07:13 2016
From: narkewoody at gmail.com (Woody Wu)
Date: Wed, 24 Feb 2016 22:07:13 +0800
Subject: Porting to an S3C2416 failed with no console message
In-Reply-To: <56CC88B3.80202@gmail.com>
References: <CAAsE_ucGBDvC8Jc6X6-=vf-uD6XMOiRQNhPKyaD8_eqAnFdz+w@mail.gmail.com>
	<56CC88B3.80202@gmail.com>
Message-ID: <CAAsE_uf7CysVuKjFiCZVpgLP53kTpVnpp7cpbLR8yTVxvWUyAA@mail.gmail.com>

On Wednesday, February 24, 2016, nick <xerofoify at gmail.com> wrote:

>
>
> On 2016-02-23 09:35 AM, Woody Wu wrote:
> > Hi,
> >
> > I am trying to port 3.18 kernel to a S3C2416.  Years ago, a guy helped me
> > ported a 3.1.0 kernel to the same board, and the guy left and the kernel
> > got too old. The guy also ported an u-boot as boot loader to load the
> 3.1.0
> > kernel.  I had the source code of the ported u-boot and the 3.1.0 linux.
> >
> > Now, my problem is that my porting of 3.18 seems not working, I did not
> see
> > any kernel message printed to the first SoC serial port as I expected. As
> > long as I can get kernel message printed to the serial, I think I can
> step
> > by step finish the whole porting work eventually. But now, there is no
> > message and I have no other hardware debugging tools and knowledges, I
> felt
> > I lost my way totally.
> >
> > I hope someone can give me some suggestions, clues to help me
> > understand where to check and what's the possible causes.
> >
> Firstly my knowledge with kernel upstream porting to a non mainlined
> port is not as good as some of the other people here but let's see what
> I can do.

> Since I found the old porting of the 3.1.0 is quit similar to SMDK2416,
> > then I started my work from also the SMDK2416 board code in 3.18.
> > Basically, I defined the machine-code to match that passed from u-boot,
> and
> > copied the MACHINE-START definition section with removing of some
> > not-immediately-needed stuff such as USB, NAND and HMSUI etc. I also
> > enabled the S3C2410 serial driver and enabled the serial console
> supporting
> > for the Samsung SoC. Of course, I had the kernel parameter of
> > "console=ttySAC0", ttySAC0 is the Linux device name of the first UART
> port
> > in the SoC. These are basically what I had done and I guess the SoC
> serial
> > part between my board and SMDK2416 should be very similar and the kernel
> > should at least be able to print it's first message then I should have
> > chance to fix other differences. But there is no kernel message at all
> as I
> > mentioned above.
> >

Can you either send me the patch series that the other developer used to
> port
> your port to 3.1.0 or I would recommend stating on kernel 3.1.0 as it's
> still
> a longterm kernel unless you have reason to upgrade. If you do I would
> recommend
> you either get something with experience or yourself to try and upstream
> the
> differences between your board and the mainline so others will not have to
> do
> the same work as you unless your company will not allow you to do this.
> > What should I check for the problem usually? Is there a checking list to
> go
> > through? I hope you experts can give me some clues.  Thanks in advance!
> >


To make a patch, I have to have the original 3.1.0, but I was confused
about how the kernel.org organized, I just cannot find how to get a 3.1.0
tarball or git repository.  Can you please give me a hint?  BTW, I also
dont really understand what the 'mainline' mens. If I download a latest
3.18.27.tar.xz,  is it a mainline?


> Their are two things you can do here either try and enable early_printk as
> this
> seems to be happening before the serial console is able to print the first
> kernel
> message. The second is trying to enable kgdb on the board and use another
> computer
> over the serial port to do this sort of debugging.
> Hope this gets you started,
> Nick


Firstly, I will try early_printk soon.  Before that, can your tell me what
are differences betweenthe following printing technologies: 1, early_printk
2, early_print, 3, putc used in arch/arm/compressed/misc.c.

Secondly, I have a question about kgdb.  You see the situation is that my
serial port had been initialized by the u-boot, but not yet touched by the
kernel since the kernel is not yet run and waiting for debugging, and now I
am jusr sitting in the u-boot command prompt and has an uImage kernel image
file loaded in a region of SDRAM, do you think that these all above are
enough or possible to the kgdb debugging?

Many thanks!

> Best Regards,
> > woody
> >
> >
> >
> >
> > _______________________________________________
> > Kernelnewbies mailing list
> > Kernelnewbies at kernelnewbies.org <javascript:;>
> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >
>


-- 
Life is the only flaw in an otherwise perfect nonexistence
    -- Schopenhauer

woody
public key at http://subkeys.pgp.net:11371 (narkewoody at gmail.com)
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From jonathan.nifenecker at gmail.com  Wed Feb 24 10:11:34 2016
From: jonathan.nifenecker at gmail.com (jonathan nifenecker)
Date: Wed, 24 Feb 2016 16:11:34 +0100
Subject: Does Linux kernel disables any Interrupts while going into IRQ
	handler?
In-Reply-To: <CAE_iR+jt9jXw0+nFnGH8JkSbRjpc-v8gnt2qkuAROAaTS=rDSA@mail.gmail.com>
References: <CAE_iR+jt9jXw0+nFnGH8JkSbRjpc-v8gnt2qkuAROAaTS=rDSA@mail.gmail.com>
Message-ID: <CANy0NFVwUXqN1wfrw5eTtbXPvrN6RVujZdRhGSGU+X0rAoCoHA@mail.gmail.com>

Hi,

I'll give a try on this one, I've just getting interested in the kernel,
but have a very good knowledge of microcontroller and think I can enlighten
you with some hardware explanation on that :

when an interrupt occur and is enabled, a flag is set at the hardware level
in some interrupt flag register. (this register is set to 1 by hardware
only, the software may only clear it to 0 to acknowledge the interrupt has
been treated. It may be automatically cleared when the interrupt handler
launch the appropriate function call.)

The "mask" in your bold citation is another register, the interrupt mask
register. It allow to control temporarily the execution of particular
interrupt on a case by case basis. thus letting other interrupt occurs
while preventing a particular one. (this register is set by software, you
can think of it as an "interrupt handler inhibitor register" )

Those 2 register are wired into a bitwise AND before the signal arrived in
the interrupt handler. the interrupt handler launch the appropriate
function call corresponding to an interrupt signal received.

So because of the AND logic, if the interrupt mask bit is 0 for a specific
interrupt, the interrupt handler will see no positive edge whatever the
interrupt occurred.
BUT If the interrupt occurred, the interrupt flag will still be set to 1,
and not loose the information of an interrupt occurred.

If you set back the mask to 1, 1 AND 1 =1 the signal will then propagate to
the interrupt handler and the function call will be launch right away !


wikipedia on Mask <https://en.wikipedia.org/wiki/Mask_%28computing%29>.
What may be confuse here is that the bitwise operation can be executed
completely by the hardware (instant reactivity), so you are dealing with
mask without seeing  interrupt_flag ^ interrupt_mask anywhere in the code.

Hope that help.


Jonathan

2016-02-24 13:14 GMT+01:00 priyaranjan <priyaranjan45678 at gmail.com>:

> When an Interrupt occurs most device drivers creates a critical section
> using spin_lock_irqsave or spin_lock_irq which disables the interrupt.
>
> In such a case the Interrupts are disabled by the IRQ handler. My question
> is whether Linux kernel disables any interrupts just when the IRQ handler
> executes or it just wait for the IRQ handler programmer to disable the IRQ
> in whatever way?
>
> My understanding is that Russel King has implemented IRQ_DISABLED, If this
> flag is set then only the IRQ that has occurred is disabled lately however
> enabled automatically by Kernel after IRQ handler finishes. Is that
> correct? This also happens in delayed manner.Can anyone explain me how
> exactly the IRQ disabling is delayed?
>
> From free-electrons link
> <http://free-electrons.com/kerneldoc/latest/DocBook/genericirq/Highlevel_IRQ_flow_handlers.html>,
> what I read is :-
>
> *The interrupt is kept enabled and is masked in the flow handler when an
> interrupt event happens*. This prevents losing edge interrupts on
> hardware which does not store an edge interrupt event while the interrupt
> is disabled at the hardware level.
>
> Can anyone please explain the bold line here?
>
> Regards,
>
> Priyaranjan
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
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From Valdis.Kletnieks at vt.edu  Wed Feb 24 11:53:37 2016
From: Valdis.Kletnieks at vt.edu (Valdis.Kletnieks at vt.edu)
Date: Wed, 24 Feb 2016 11:53:37 -0500
Subject: user rsyslog/syslog
In-Reply-To: <CAJ2oMhJOdRuneZ+QPvWdH_Rc7XMcPrm1ydDJyNRfSA5oc+fKXA@mail.gmail.com>
References: <CAJ2oMhK3Q5sNno0tgMoifXL5LP-iDYveKajWxgQfHCO0y_96vw@mail.gmail.com>
	<22877.1456301853@turing-police.cc.vt.edu>
	<CAJ2oMhJOdRuneZ+QPvWdH_Rc7XMcPrm1ydDJyNRfSA5oc+fKXA@mail.gmail.com>
Message-ID: <4777.1456332817@turing-police.cc.vt.edu>

On Wed, 24 Feb 2016 14:20:23 +0200, Ran Shalit said:

> Maybe the last suggestion will be the most practical if this issue
> can't be resolved, which means that I will use one file for all logs,
> in which each line will have its own tag string according to the
> application.

No, what you do is you use an rsyslog filter on the program name,
and use that to route each program's logs to a different file.
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From greg at kroah.com  Wed Feb 24 13:25:02 2016
From: greg at kroah.com (Greg KH)
Date: Wed, 24 Feb 2016 10:25:02 -0800
Subject: Is there a bug in dgnc.ko?
In-Reply-To: <20160224115701.GB1998@debian>
References: <20160224045742.GA24012@debian> <20160224054356.GA1138@kroah.com>
	<20160224115701.GB1998@debian>
Message-ID: <20160224182502.GA22830@kroah.com>

On Wed, Feb 24, 2016 at 07:57:01PM +0800, Navy Cheng wrote:
> On Tue, Feb 23, 2016 at 09:43:56PM -0800, Greg KH wrote:
> > On Wed, Feb 24, 2016 at 12:57:42PM +0800, Navy Cheng wrote:
> > > Hi,
> > > 
> > > My kernel version is v4.4, and I have built drivers/staging/dgnc/dgnc.ko.
> > > I change to *dir*/drivers/staging/dgnc and do like this:
> > > 
> > >     sudo insmod ./dgnc.ko
> > 
> > Do you have the hardware that this driver controls?
> 
> I'm not sure. My laptop is Dell Inspiron 14R - 5437 and I don't know if
> there is the right hardware. I often don't know about what a driver is used
> for in drivers/staging/. Is there any good way to know the function of a
> driver or module?

If you don't think you have the hardware, then almost always, you don't
have the hardware, it's pretty simple :)

> > 
> > >     sudo lsmod | grep dgnc
> > 
> > Does that show anything?
> 
> Output: dgnc                   65536  0

Great, it loaded, then crashes when you unload, congratulations, you can
now work on fixing that bug!

good luck,

greg k-h


From sunitad100 at gmail.com  Wed Feb 24 21:40:24 2016
From: sunitad100 at gmail.com (SUNITA)
Date: Thu, 25 Feb 2016 08:10:24 +0530
Subject: Project Idea..
In-Reply-To: <20160222161843.GA25683@kroah.com>
References: <CAMEb3oqQ3-cx0faqCxJTNkK8A5tjs_ozZ0X6-FycBvdOt2K=KQ@mail.gmail.com>
	<20160222161843.GA25683@kroah.com>
Message-ID: <CAMEb3orSdiwR8tciauhcNMRzdhOp3DzHBp3=OdgGtvUgd5PuYw@mail.gmail.com>

Hello,

I want to measure the battery usage of various  applications in linux.
I executed powerstat and powertop tools.  Are there any other tools
which indicate the power consumption by programs in linux.

I want to calculate the power used by various scheduling programs.

Also can Sysbench be an alternative to Mibench.

Regards,
Sunita


On 2/22/16, Greg KH <greg at kroah.com> wrote:
> On Mon, Feb 22, 2016 at 10:54:54AM +0530, SUNITA wrote:
>> Respected Sir/Madam,
>> I am trying to study the effect of Scheduler Policies on Energy
>> Consumption of Portable Device.
>
> There are lots of people currently working on this, and have been for
> many years.  I know of at least 3 complete implementations at the
> moment (two of which ship in some Android phones), so I would suggest
> working with one of those groups to try to get their code merged into
> the Linux kernel.  To create a 4th implementation would seem like a bit
> of a redundant effort.
>
> Search the archives of lwn.net for details about this if you are
> interested.
>
> good luck!
>
> greg k-h
>


From priyaranjan45678 at gmail.com  Thu Feb 25 01:07:32 2016
From: priyaranjan45678 at gmail.com (priyaranjan)
Date: Thu, 25 Feb 2016 11:37:32 +0530
Subject: Mutex and Spinlock locked together
Message-ID: <CAE_iR+hAzRssjgaZMJ-T6N7gsp46kXGVU4KLy0B+wXwiVqik3w@mail.gmail.com>

Hello All,

Do you have any idea of a situation where we would need mutex and spinlock
to be locked together? I think there is an example for this in Linux
kernel. Can anyone help me?

Regards,
Priyaranjan
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From navych at 126.com  Thu Feb 25 02:05:14 2016
From: navych at 126.com (Navy Cheng)
Date: Thu, 25 Feb 2016 15:05:14 +0800
Subject: Is there a bug in dgnc.ko?
In-Reply-To: <CADVatmM3GYxire8KEYuBj3DmVN+=aqzYzgCMOrGkXW2wn3fvGg@mail.gmail.com>
References: <20160224045742.GA24012@debian> <20160224054356.GA1138@kroah.com>
	<20160224115701.GB1998@debian>
	<CADVatmM3GYxire8KEYuBj3DmVN+=aqzYzgCMOrGkXW2wn3fvGg@mail.gmail.com>
Message-ID: <20160225070514.GA26084@debian>

On Wed, Feb 24, 2016 at 05:33:11PM +0530, Sudip Mukherjee wrote:
> On Wed, Feb 24, 2016 at 5:27 PM, Navy Cheng <navych at 126.com> wrote:
> > On Tue, Feb 23, 2016 at 09:43:56PM -0800, Greg KH wrote:
> >> On Wed, Feb 24, 2016 at 12:57:42PM +0800, Navy Cheng wrote:
> >> > Hi,
> >> >
> >> > My kernel version is v4.4, and I have built drivers/staging/dgnc/dgnc.ko.
> >> > I change to *dir*/drivers/staging/dgnc and do like this:
> >> >
> >> >     sudo insmod ./dgnc.ko
> >>
> >> Do you have the hardware that this driver controls?
> >
> > I'm not sure. My laptop is Dell Inspiron 14R - 5437 and I don't know if
> > there is the right hardware. I often don't know about what a driver is used
> > for in drivers/staging/. Is there any good way to know the function of a
> > driver or module?
> >
> >>
> >> >     sudo lsmod | grep dgnc
> >>
> >> Does that show anything?
> >
> > Output: dgnc                   65536  0
> >
> >> >     sudo rmmod ./dgnc
> 
> what did dmesg showed after you did rmmod?
> 

*dmesg* show nothing after I rmmod dgnc. I guess something wrong with
dgnc_cleanup_module() which is called when dgnc is removed.



From devesh28 at gmail.com  Thu Feb 25 04:23:43 2016
From: devesh28 at gmail.com (Devesh Sharma)
Date: Thu, 25 Feb 2016 14:53:43 +0530
Subject: Mutex and Spinlock locked together
In-Reply-To: <CAE_iR+hAzRssjgaZMJ-T6N7gsp46kXGVU4KLy0B+wXwiVqik3w@mail.gmail.com>
References: <CAE_iR+hAzRssjgaZMJ-T6N7gsp46kXGVU4KLy0B+wXwiVqik3w@mail.gmail.com>
Message-ID: <CALsNU1NGVgGhMSQ8t=T+0Hh5VTs-uYxx_VALEVHp6okJxoyUcw@mail.gmail.com>

Hi

In running kernel there are many places you can look to get the usage. But
the bottom line is

* You can take a spinlock under a mutex. e.g.
mutex_lock--->spinlock-----critical section-----spinunlock--->mutex_unlock.

* You can not take a mutex under a spinlock. e.g. spinlock--->mutex_lock
-----critical section ....mutex_unlock---->spinunlock is not allowed.


On Thu, Feb 25, 2016 at 11:37 AM, priyaranjan <priyaranjan45678 at gmail.com>
wrote:

> Hello All,
>
> Do you have any idea of a situation where we would need mutex and spinlock
> to be locked together? I think there is an example for this in Linux
> kernel. Can anyone help me?
>
> Regards,
> Priyaranjan
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>


-- 
Please don't print this E- mail unless you really need to - this will
preserve trees on planet earth.
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From priyaranjan45678 at gmail.com  Thu Feb 25 05:12:24 2016
From: priyaranjan45678 at gmail.com (priyaranjan)
Date: Thu, 25 Feb 2016 15:42:24 +0530
Subject: Mutex and Spinlock locked together
In-Reply-To: <CALsNU1NGVgGhMSQ8t=T+0Hh5VTs-uYxx_VALEVHp6okJxoyUcw@mail.gmail.com>
References: <CAE_iR+hAzRssjgaZMJ-T6N7gsp46kXGVU4KLy0B+wXwiVqik3w@mail.gmail.com>
	<CALsNU1NGVgGhMSQ8t=T+0Hh5VTs-uYxx_VALEVHp6okJxoyUcw@mail.gmail.com>
Message-ID: <CAE_iR+j7EOXkRNpM9EigfDWEsACjc-c1VxAfjxhU3LbFqSeZ0Q@mail.gmail.com>

>On Thu, Feb 25, 2016 at 2:53 PM, Devesh Sharma <devesh28 at gmail.com> wrote:
>Hi

>In running kernel there are many places you can look to get the usage. But
the bottom line is

Can you tell me the specific use case?  or give me the file name/driver
where this is used.

>* You can take a spinlock under a mutex. e.g.
mutex_lock--->spinlock-----critical section-----spinunlock--->mutex_unlock.

>* You can not take a mutex under a spinlock. e.g. spinlock--->mutex_lock
-----critical section ....mutex_unlock---->spinunlock is not allowed.


On Thu, Feb 25, 2016 at 11:37 AM, priyaranjan <priyaranjan45678 at gmail.com>
wrote:
Hello All,

Do you have any idea of a situation where we would need mutex and spinlock
to be locked together? I think there is an example for this in Linux
kernel. Can anyone help me?

Regards,
Priyaranjan

_______________________________________________
Kernelnewbies mailing list
Kernelnewbies at kernelnewbies.org
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
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From devesh28 at gmail.com  Thu Feb 25 05:27:49 2016
From: devesh28 at gmail.com (Devesh Sharma)
Date: Thu, 25 Feb 2016 15:57:49 +0530
Subject: Mutex and Spinlock locked together
In-Reply-To: <CAE_iR+j7EOXkRNpM9EigfDWEsACjc-c1VxAfjxhU3LbFqSeZ0Q@mail.gmail.com>
References: <CAE_iR+hAzRssjgaZMJ-T6N7gsp46kXGVU4KLy0B+wXwiVqik3w@mail.gmail.com>
	<CALsNU1NGVgGhMSQ8t=T+0Hh5VTs-uYxx_VALEVHp6okJxoyUcw@mail.gmail.com>
	<CAE_iR+j7EOXkRNpM9EigfDWEsACjc-c1VxAfjxhU3LbFqSeZ0Q@mail.gmail.com>
Message-ID: <CALsNU1NGNhu8NXhAbdrRbuVtPg+WYtfdYzK7_yUaF0m1-pw0gg@mail.gmail.com>

Check this out:

drivers/infiniband/core/cache.c

function: ib_cache_gid_add

Line: 338

mutex_lock(&table->lock);
        write_lock_irq(&table->rwlock);
.
.
.
.
 write_unlock_irq(&table->rwlock);
        mutex_unlock(&table->lock);

On Thu, Feb 25, 2016 at 3:42 PM, priyaranjan <priyaranjan45678 at gmail.com>
wrote:

> >On Thu, Feb 25, 2016 at 2:53 PM, Devesh Sharma <devesh28 at gmail.com>
> wrote:
> >Hi
>
> >In running kernel there are many places you can look to get the usage.
> But the bottom line is
>
> Can you tell me the specific use case?  or give me the file name/driver
> where this is used.
>
> >* You can take a spinlock under a mutex. e.g.
> mutex_lock--->spinlock-----critical section-----spinunlock--->mutex_unlock.
>
> >* You can not take a mutex under a spinlock. e.g. spinlock--->mutex_lock
> -----critical section ....mutex_unlock---->spinunlock is not allowed.
>
>
> On Thu, Feb 25, 2016 at 11:37 AM, priyaranjan <priyaranjan45678 at gmail.com>
> wrote:
> Hello All,
>
> Do you have any idea of a situation where we would need mutex and spinlock
> to be locked together? I think there is an example for this in Linux
> kernel. Can anyone help me?
>
> Regards,
> Priyaranjan
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
>
>


-- 
Please don't print this E- mail unless you really need to - this will
preserve trees on planet earth.
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From narkewoody at gmail.com  Thu Feb 25 11:55:40 2016
From: narkewoody at gmail.com (Woody Wu)
Date: Fri, 26 Feb 2016 00:55:40 +0800
Subject: How to use earlycon and earlyprintk on Samsung S3C24xx
Message-ID: <CAAsE_uctGn=bjhNrhDBeDMhACSiqgjo5dOHB9wW-n1O7W3GoZw@mail.gmail.com>

Hi,

It seems, at least in 4.4.2 kernel, earlyprintk parameter supports
something like 's3c24xx,<addr>'. But I dont know where to find out the addr
value of the first uart port on my *s3c2416* based board.  Can someone
please tell me?

Also, I desire to know if the earlycon parameter supports the Samsung
S3C24xx uarts, if so, what should the value of the parameter look like?

Thank in advance,

-woody


-- 
Life is the only flaw in an otherwise perfect nonexistence
    -- Schopenhauer

woody
public key at http://subkeys.pgp.net:11371 (narkewoody at gmail.com)
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From victorascroft at gmail.com  Thu Feb 25 13:40:10 2016
From: victorascroft at gmail.com (victorascroft at gmail.com)
Date: Fri, 26 Feb 2016 00:10:10 +0530
Subject: How to use earlycon and earlyprintk on Samsung S3C24xx
In-Reply-To: <CAAsE_uctGn=bjhNrhDBeDMhACSiqgjo5dOHB9wW-n1O7W3GoZw@mail.gmail.com>
References: <CAAsE_uctGn=bjhNrhDBeDMhACSiqgjo5dOHB9wW-n1O7W3GoZw@mail.gmail.com>
Message-ID: <20160225184010.GA29444@Sanchayan-Arch>

Hi,

On 16-02-26 00:55:40, Woody Wu wrote:
> Hi,
> 
> It seems, at least in 4.4.2 kernel, earlyprintk parameter supports
> something like 's3c24xx,<addr>'. But I dont know where to find out the addr
> value of the first uart port on my *s3c2416* based board.  Can someone
> please tell me?
> 
> Also, I desire to know if the earlycon parameter supports the Samsung
> S3C24xx uarts, if so, what should the value of the parameter look like?

Have a look in the documentation here
https://www.kernel.org/doc/Documentation/kernel-parameters.txt

The kernels kernel-parameter.txt documentation file lists the supported drivers. 

Generally the UART0 port is used for debugging but I guess there is
no such hard and fast rule.

For your particular board, you can check which UART port is used
as the debug serial console and then get the address for the concerned
UART by checking the relevant dtsi file in
arch/arm/boot/dts/s3c24xx.dtsi or perhaps one of the exynosX.dtsi files?

UART0 port seems to have address of 0x50000000?

Regards,
Sanchayan.

> 
> Thank in advance,
> 
> -woody
> 
> 
> -- 
> Life is the only flaw in an otherwise perfect nonexistence
>     -- Schopenhauer
> 
> woody
> public key at http://subkeys.pgp.net:11371 (narkewoody at gmail.com)

> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies



From xiaonan830818 at gmail.com  Fri Feb 26 05:13:02 2016
From: xiaonan830818 at gmail.com (Nan Xiao)
Date: Fri, 26 Feb 2016 18:13:02 +0800
Subject: How to understan /proc/sys/kernel/sched_domain/cpu$/domain$/flags?
Message-ID: <CA+MhoaP8wzLoZqVqbERVGxWNQRyamWYA_6J0UiTsysWYfia4fQ@mail.gmail.com>

Hi all,

I find there is a flags file under
/proc/sys/kernel/sched_domain/cpu$/domain$ directory,
but can't figure out the meaning of this file:

# cat flags
687

Could anyone tell me where I can find the definition of this file? Thanks
in advance!

Best Regards
Nan Xiao
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From cakturk at gmail.com  Fri Feb 26 09:18:30 2016
From: cakturk at gmail.com (Cihangir Akturk)
Date: Fri, 26 Feb 2016 16:18:30 +0200
Subject: How to understan /proc/sys/kernel/sched_domain/cpu$/domain$/flags?
In-Reply-To: <CA+MhoaP8wzLoZqVqbERVGxWNQRyamWYA_6J0UiTsysWYfia4fQ@mail.gmail.com>
References: <CA+MhoaP8wzLoZqVqbERVGxWNQRyamWYA_6J0UiTsysWYfia4fQ@mail.gmail.com>
Message-ID: <20160226141830.GA2556@portege.ulakbim.gov.tr>

On Fri, Feb 26, 2016 at 06:13:02PM +0800, Nan Xiao wrote:
> Hi all,
> 
> I find there is a flags file under
> /proc/sys/kernel/sched_domain/cpu$/domain$ directory,
> but can't figure out the meaning of this file:
> 
> # cat flags
> 687
> 
> Could anyone tell me where I can find the definition of this file? Thanks

Hi Nan,

A quick grep on the source tree gives the following results;
http://lxr.free-electrons.com/source/kernel/sched/core.c?v=4.2#L5221

> in advance!
> 
> Best Regards
> Nan Xiao


From navych at 126.com  Mon Feb 29 01:41:34 2016
From: navych at 126.com (Navy Cheng)
Date: Mon, 29 Feb 2016 14:41:34 +0800
Subject: [PATCH] staging: dgnc: Remove useless and deadly judgment
Message-ID: <20160229064133.GA14862@debian>

pci_unregister_driver() should be used once dgnc module exit. It has
nothing to do with dgnc_NumBoards. Remove the judgment of dgnc_NumBoards to
avoid pci_unregister_driver() is not used when dgnc_NumBoards is 0.

Signed-off-by: Navy Cheng <navych at 126.com>
---
 drivers/staging/dgnc/dgnc_driver.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/staging/dgnc/dgnc_driver.c b/drivers/staging/dgnc/dgnc_driver.c
index fc6d298..20b0c3b 100644
--- a/drivers/staging/dgnc/dgnc_driver.c
+++ b/drivers/staging/dgnc/dgnc_driver.c
@@ -156,8 +156,7 @@ static void dgnc_cleanup_module(void)
 
 	dgnc_tty_post_uninit();
 
-	if (dgnc_NumBoards)
-		pci_unregister_driver(&dgnc_driver);
+	pci_unregister_driver(&dgnc_driver);
 }
 
 /*
-- 
2.1.4




From Valdis.Kletnieks at vt.edu  Mon Feb 29 02:58:16 2016
From: Valdis.Kletnieks at vt.edu (Valdis.Kletnieks at vt.edu)
Date: Mon, 29 Feb 2016 02:58:16 -0500
Subject: [PATCH] staging: dgnc: Remove useless and deadly judgment
In-Reply-To: <20160229064133.GA14862@debian>
References: <20160229064133.GA14862@debian>
Message-ID: <15064.1456732696@turing-police.cc.vt.edu>

On Mon, 29 Feb 2016 14:41:34 +0800, Navy Cheng said:
> pci_unregister_driver() should be used once dgnc module exit. It has
> nothing to do with dgnc_NumBoards. Remove the judgment of dgnc_NumBoards to
> avoid pci_unregister_driver() is not used when dgnc_NumBoards is 0.

> -	if (dgnc_NumBoards)
> -		pci_unregister_driver(&dgnc_driver);
> +	pci_unregister_driver(&dgnc_driver);

Does pci_unregister_driver do the right thing if there are 0 boards
in the system?

If this logic is wrong, shouldn't there also be a patch fixing the
following in dgnc_init_module()?

        /*
         * Find and configure all the cards
         */
        rc = pci_register_driver(&dgnc_driver);

        /*
         * If something went wrong in the scan, bail out of driver.
         */
        if (rc < 0) {
                /* Only unregister if it was actually registered. */
                if (dgnc_NumBoards)
                        pci_unregister_driver(&dgnc_driver);
                else
                        pr_warn("WARNING: dgnc driver load failed.  No Digi Neo or Classic boards found.\n");

                dgnc_cleanup_module();

While I'm at it, the entire NumBoards counting seems to be wonky - it looks
like a *lot* of off-by-one errors.  Looks like the programmer(s) weren't sure
if they wanted to use that as a zero-based or one-based counter/index.

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From martinhoury at gmail.com  Mon Feb 29 05:47:16 2016
From: martinhoury at gmail.com (Martin Houry)
Date: Mon, 29 Feb 2016 11:47:16 +0100
Subject: Question : How to access to bandwith statistics from kernel space?
Message-ID: <CAEUt8VLzc0T9WH1nfAQat7kLj1HUEsfsnSu7cbNrxqdtDsZvbQ@mail.gmail.com>

I have made some research and I could't find a library  who can give
me interfaces's statistics like max/min/average bandwidth, jitter, ...

Do you know a way to do this?

Thank you
Martin


From navych at 126.com  Mon Feb 29 07:27:41 2016
From: navych at 126.com (Navy Cheng)
Date: Mon, 29 Feb 2016 20:27:41 +0800
Subject: [PATCH] staging: dgnc: Remove useless and deadly judgment
In-Reply-To: <15064.1456732696@turing-police.cc.vt.edu>
References: <20160229064133.GA14862@debian>
	<15064.1456732696@turing-police.cc.vt.edu>
Message-ID: <20160229122740.GA11064@debian>

On Mon, Feb 29, 2016 at 02:58:16AM -0500, Valdis.Kletnieks at vt.edu wrote:
> On Mon, 29 Feb 2016 14:41:34 +0800, Navy Cheng said:
> > pci_unregister_driver() should be used once dgnc module exit. It has
> > nothing to do with dgnc_NumBoards. Remove the judgment of dgnc_NumBoards to
> > avoid pci_unregister_driver() is not used when dgnc_NumBoards is 0.
> 
> > -	if (dgnc_NumBoards)
> > -		pci_unregister_driver(&dgnc_driver);
> > +	pci_unregister_driver(&dgnc_driver);
> 
> Does pci_unregister_driver do the right thing if there are 0 boards
> in the system?

I have no dgnc device in my laptop. After *insmod* and *rmmod* dgnc module,
I can re-insmod dgnc successfully. If dgnc is *rmmod*, the dgnc-file in /sys
will disappear.

> If this logic is wrong, shouldn't there also be a patch fixing the
> following in dgnc_init_module()?

Yes, I thought dgnc_init_module should be fixed. But I'm not familiar with
how to submitting patchset. I decide to fix dgnc_cleanup_module() first.

>         /*
>          * Find and configure all the cards
>          */
>         rc = pci_register_driver(&dgnc_driver);
> 
>         /*
>          * If something went wrong in the scan, bail out of driver.
>          */
>         if (rc < 0) {
>                 /* Only unregister if it was actually registered. */
>                 if (dgnc_NumBoards)
>                         pci_unregister_driver(&dgnc_driver);
>                 else
>                         pr_warn("WARNING: dgnc driver load failed.  No Digi Neo or Classic boards found.\n");
> 
>                 dgnc_cleanup_module();
> 
> While I'm at it, the entire NumBoards counting seems to be wonky - it looks
> like a *lot* of off-by-one errors.  Looks like the programmer(s) weren't sure
> if they wanted to use that as a zero-based or one-based counter/index.
> 

Maybe we can fix the *init* and *exit* like this:

    static int __init dgnc_init_module(void)
    {
        int rc;

        rc = dgnc_start();
	if (rc < 0)
            goto err1;

        rc = pci_register_driver(&dgnc_driver)
	if (rc <0) {
	    goto err1;
	    pr_warn("....");
	}

        rc = dgnc_create_driver_sysfiles(&dgnc_driver);

	if (rc = 0)
            goto err2;

	return rc;
	 
    err2:
        pci_unregister_driver(&dgnc_driver);
    err1:
        dgnc_end();

	return rc;
    }
    
    static void dgnc_cleanup_module(void)
    {
        int i;

	dgnc_remove_driver_sysfiles(&dgnc_driver);

	for (i = 0; i < dgnc_NumBoards; ++i) {
	    dgnc_remove_ports_sysfiles(dgnc_Board[i]);
            dgnc_tty_uninit(dgnc_Board[i]);
	    dgnc_cleanup_board(dgnc_Board[i]);
	}

        pci_unregister_driver(&dgnc_driver);

     	dgnc_end();
    }
	



From Valdis.Kletnieks at vt.edu  Mon Feb 29 11:10:35 2016
From: Valdis.Kletnieks at vt.edu (Valdis.Kletnieks at vt.edu)
Date: Mon, 29 Feb 2016 11:10:35 -0500
Subject: Question : How to access to bandwith statistics from kernel space?
In-Reply-To: <CAEUt8VLzc0T9WH1nfAQat7kLj1HUEsfsnSu7cbNrxqdtDsZvbQ@mail.gmail.com>
References: <CAEUt8VLzc0T9WH1nfAQat7kLj1HUEsfsnSu7cbNrxqdtDsZvbQ@mail.gmail.com>
Message-ID: <54062.1456762235@turing-police.cc.vt.edu>

On Mon, 29 Feb 2016 11:47:16 +0100, Martin Houry said:
> I have made some research and I could't find a library  who can give
> me interfaces's statistics like max/min/average bandwidth, jitter, ...
>
> Do you know a way to do this?

What problem are you trying to solve from within the kernel with those
statistics?

You probably should look at how the various TCP congestion routines work.
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From sunitad100 at gmail.com  Mon Feb 29 20:30:36 2016
From: sunitad100 at gmail.com (SUNITA)
Date: Tue, 1 Mar 2016 07:00:36 +0530
Subject: Project Idea..
In-Reply-To: <CAMEb3orSdiwR8tciauhcNMRzdhOp3DzHBp3=OdgGtvUgd5PuYw@mail.gmail.com>
References: <CAMEb3oqQ3-cx0faqCxJTNkK8A5tjs_ozZ0X6-FycBvdOt2K=KQ@mail.gmail.com>
	<20160222161843.GA25683@kroah.com>
	<CAMEb3orSdiwR8tciauhcNMRzdhOp3DzHBp3=OdgGtvUgd5PuYw@mail.gmail.com>
Message-ID: <CAMEb3opcQ3E6u8+Oo2OfPFHJ6myX-Zi=CGT4iY4TJDBU7DHTFg@mail.gmail.com>

There are four scheduling policies.  Is it feasible if i design a
scheduling policy which will overcome the drawbacks of sched_RR.
The purpose is to reduce the number of context switches.
I have to modify fair.c

Regards,
Sunita
On 25 Feb 2016 08:10, "SUNITA" <sunitad100 at gmail.com> wrote:

> Hello,
>
> I want to measure the battery usage of various  applications in linux.
> I executed powerstat and powertop tools.  Are there any other tools
> which indicate the power consumption by programs in linux.
>
> I want to calculate the power used by various scheduling programs.
>
> Also can Sysbench be an alternative to Mibench.
>
> Regards,
> Sunita
>
>
> On 2/22/16, Greg KH <greg at kroah.com> wrote:
> > On Mon, Feb 22, 2016 at 10:54:54AM +0530, SUNITA wrote:
> >> Respected Sir/Madam,
> >> I am trying to study the effect of Scheduler Policies on Energy
> >> Consumption of Portable Device.
> >
> > There are lots of people currently working on this, and have been for
> > many years.  I know of at least 3 complete implementations at the
> > moment (two of which ship in some Android phones), so I would suggest
> > working with one of those groups to try to get their code merged into
> > the Linux kernel.  To create a 4th implementation would seem like a bit
> > of a redundant effort.
> >
> > Search the archives of lwn.net for details about this if you are
> > interested.
> >
> > good luck!
> >
> > greg k-h
> >
>
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From greg at kroah.com  Mon Feb 29 21:47:20 2016
From: greg at kroah.com (Greg KH)
Date: Mon, 29 Feb 2016 18:47:20 -0800
Subject: Project Idea..
In-Reply-To: <CAMEb3opcQ3E6u8+Oo2OfPFHJ6myX-Zi=CGT4iY4TJDBU7DHTFg@mail.gmail.com>
References: <CAMEb3oqQ3-cx0faqCxJTNkK8A5tjs_ozZ0X6-FycBvdOt2K=KQ@mail.gmail.com>
	<20160222161843.GA25683@kroah.com>
	<CAMEb3orSdiwR8tciauhcNMRzdhOp3DzHBp3=OdgGtvUgd5PuYw@mail.gmail.com>
	<CAMEb3opcQ3E6u8+Oo2OfPFHJ6myX-Zi=CGT4iY4TJDBU7DHTFg@mail.gmail.com>
Message-ID: <20160301024720.GA17219@kroah.com>

On Tue, Mar 01, 2016 at 07:00:36AM +0530, SUNITA wrote:
> There are four scheduling policies.? Is it feasible if i design a scheduling
> policy which will overcome the drawbacks of sched_RR.?
> The purpose is to reduce the number of context switches.
> I have to modify fair.c

That sounds like a homework question, why are you trying to do this
without doing research into how it has already been solved 4 different
times?

Hint, if you have an Android phone, odds are one of those solutions is
in the kernel in it, go get the source tree and look at the changes that
were made.

good luck,

greg k-h