January 2012 - kernelnewbies@kernelnewbies.org

usage of _GPL
by sumeet linux Jan. 19, 2012

Jan. 19, 2012

Hi All, Can anyone clarify that when should I use _GPL and when not ? Is there a policy like for new code, it must be _GPL ? I see in kernel many places _GPL used like EXPORT_SYMBOL_GPL( ), but many places only EXPORT_SYMBOL( ). Regards, Sumeet

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Re: kernel module parameter
by Simon Leung Jan. 18, 2012

Jan. 18, 2012

Thanks. When was this interface introduced? I can't find it on my system but my kernel is a bit old. On 18/01/12 15:26, Manohar Vanga wrote: > $ ls /sys/module/MODULE_NAME/parameters/ > > On Wed, Jan 18, 2012 at 4:20 PM, Simon Leung <simonleung(a)gmx.com > <mailto:simonleung@gmx.com>> wrote: > > Hi all, > > Is there a way to find out what parameters were used when loading the > kernel module. E.g. After loading the driver with 'insmode foo.ko > param1=bla'. How can find out later on about those parameter? > > > Thanks, > > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies(a)kernelnewbies.org > <mailto:Kernelnewbies@kernelnewbies.org> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > > > > -- > /manohar

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kernel module parameter
by Simon Leung Jan. 18, 2012

Jan. 18, 2012

Hi all, Is there a way to find out what parameters were used when loading the kernel module. E.g. After loading the driver with 'insmode foo.ko param1=bla'. How can find out later on about those parameter? Thanks,

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Re: Does Linux process exist information leakage?
by beyond.hack Jan. 18, 2012

Jan. 18, 2012

Experts.. > As we know that in virtual memory, virtual pages are allocated for a > process..and when that memory is used page fault occurs and then handler > allocates a page frame i.e. Real physical memory..hence our small physical > memory are able to handle bigger processes... > so a information, certainly comes to the "ram" atleast a time... > So can we do something if we have something that can have DMA ??? > I am just guessing!! > Plz do suggest..and correct me if i am wrong!!! > >

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Re: USB controller status
by Greg KH Jan. 17, 2012

Jan. 17, 2012

On Tue, Jan 17, 2012 at 07:26:24PM +0530, Praveen kumar wrote: > Hi Greg, > > What type of diagnostics are you trying to do? > I am trying to is to make communication to all the chips present on > board (from kernel) and make sure all the input/output lines are working on > that chip and the status of the configuration. > As I am doing with the other chips like video controller ,audio controller etc > ,I want to make sure the working condition of the USB controller and some tests > to prove input and output lines are working and if possible loop back data > test. Good luck with that, it might be hard to do from within the kernel :) > How can it not be configured correctly? > > I am not sure in which condition the configuration of controller may fail but > just I want to make sure the controller is configured properly. > > You have looked at the debugfs files for the usb controllers for this > type of thing already, right? > > I have seen debugfs where I can dump all the configuration reg values ,but not > sure to see which reg values to confirm controller is configured properly. > > Also I was trying to get the linux-usb project (http://sourceforge.net/apps/ > trac/sourceforge/wiki/Git) through git to make use of some code in there for > some of the tests but I am not able to get it. > Is there any alternative link from where I can get the code (like lsusb.c etc > ).. usbutils are on github, look in your distro for the location of the source. greg k-h

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USB controller status
by Praveen kumar Jan. 17, 2012

Jan. 17, 2012

Hi All, As part of diagnostics I have to make sure the USB controller is configured correctly. Can I get this information from any entry in /sys or /proc ?? If yes where ?? If no I plan to add a exclusive entry in the driver to do my diagnostics. Is that feasible by reading some of the registers in the controller ?? Praveen

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two netcard configed in one subnet problem
by hu jun Jan. 17, 2012

Jan. 17, 2012

two linux machines A and B , they are in one network: 192.168.160.0 A has two netcards: eth0 Link encap:Ethernet HWaddr 00:0C:29:F9:DD:29 inet addr:192.168.160.11 Bcast:192.168.160.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:fef9:dd29/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:448 errors:0 dropped:0 overruns:0 frame:0 TX packets:361 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:42722 (41.7 Kb) TX bytes:46887 (45.7 Kb) eth1 Link encap:Ethernet HWaddr 00:0C:29:F9:DD:33 inet addr:192.168.160.21 Bcast:192.168.160.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:fef9:dd33/64 Scope:Link UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:73 errors:0 dropped:0 overruns:0 frame:0 TX packets:7 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:9926 (9.6 Kb) TX bytes:578 (578.0 b) B has one netcard: eth0 Link encap:Ethernet HWaddr 00:0C:29:A9:5F:E2 inet addr:192.168.160.12 Bcast:192.168.160.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:fea9:5fe2/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:793 errors:0 dropped:0 overruns:0 frame:0 TX packets:649 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:74366 (72.6 Kb) TX bytes:80645 (78.7 Kb) Interrupt:17 Base address:0x2000 now on B :ping 192.168.160.11 and 192.168.160.21, both are ok run arp -a,result is as follows:? (192.168.160.21) at 00:0C:29:F9:DD:29 [ether] on eth0? (192.168.0.59) at 00:0C:29:F9:DD:1F [ether] on eth1? (192.168.160.1) at 00:50:56:C0:00:01 [ether] on eth0? (192.168.0.1) at 00:11:95:CD:35:66 [ether] on eth1Vsles11sp1 (192.168.160.11) at 00:0C:29:F9:DD:29 [ether] on eth0 then I unplug eth1 , ethtool eth1 show "Link detected: no", now on B :ping 192.168.160.11 and 192.168.160.21, both are ok, too. I was confused that things. Google , I has understanded a little . on A , I run "echo 1 >/proc/sys/net/ipv4/conf/all/arp_ignore",then on B , ping ping 192.168.160.11 and 192.168.160.21, both still are ok Can you give me advise ? What will I do for on B pinging 192.168.160.21 is not ok?

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High sleep_on_page latency
by Prateek Sharma Jan. 16, 2012

Jan. 16, 2012

Hello, I am measuring system latency using latencytop. I am using kernel version 3.0 with some minor changes. The latencytop output for the process doing the IO (qemu) is below: Process qemu-system-x86 (6239) Total: 31363.7 msec [sleep_on_page] 1966.5 msec 81.4 % Waiting for event (select) 5.0 msec 7.8 % [kvm_vcpu_block] 5.0 msec 8.5 % synchronous write 1.7 msec 0.0 % Userspace lock contention 1.5 msec 2.3 % Is the 2000 msec sleep_on_page delays normal ? I would also like to know what sleep_on_page exactly corresponds to. My understanding is that it is the time spent waiting for grabbing a lock on a page. Is this correct ? Thanks.

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Current Thread mapping
by SaNtosh kuLkarni Jan. 16, 2012

Jan. 16, 2012

HI everyone just wanted to know whats the current implementation of user|| kernel space thread mapping ...is it 1:1 or does it depend on the needs ? For example say if i have 12k user space thread running ,,,how many kernel space thread would be managing them... as far as i know there is 1:1 mappin Thanks -- *Regards, Santi*

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which local FS supports concurrent direct IO write?
by Zheng Da Jan. 15, 2012

Jan. 15, 2012

Hello, I'm looking for a FS in Linux that supports concurrent direct IO write. ext4 supports concurrent direct IO read if we mount it with dioread_nolock, but doesn't support concurrent writes. XFS doesn't support concurrent direct IO at all. It locks the inode exclusive if it's direct IO. I tried btrfs, and it seems it doesn't support concurrent direct IO either though I haven't looked into its code. Is there a local FS that support concurrent direct IO write? It seems NFS supports it ( http://kevinclosson.wordpress.com/2011/08/12/file-systems-for-a-database-ch…) but I'm looking for local FS. Thanks, Da

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