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PCI IO memory resource allocation
by J.Hwan Kim Aug. 18, 2011

Aug. 18, 2011

Hi, everyone In kernel source, where is the PCI IO memory resource allocation is done? (memory mapped io) And can you explain the IO memory resource allocation mechanism? Thanks in advance Best Regards, J.Hwan Kim

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How to reinstall modified custom kernel?
by Amirali Shambayati Aug. 18, 2011

Aug. 18, 2011

Hi all, Last time, I emailed to linux-kernel and kernenewbies mailing-lists about how to speed up kernel compilation. I received very useful peace of advice about using "ccache". Now I want to modify and compile a unique custom kernel several times. I used https://help.ubuntu.com/community/Kernel/Compile to compile custom kernel. This tutorial uses "kpkg" command to build kernel and it produces two .deb files: "linux-image" and "linux-header" as result. So for the first time I followed this tutorial. For next times, according to to experts' advice, I use "make all" in custom kernel root directory to rebuild kernel. I am not sure that it would be enough to use *changed kernel* after rebooting. As I asked from some experts, It is also required to install kernel again, but they were not familiar with "kpkg" and "dpkg",... commands for kernel installation. Should I use "dbkg" command after every time I rebuild kernel, for re-installation? If anybody is familiar with these method of kernel installation, please help me. It is very urgent, because it is related to my B.S. thesis :P Regards, -- Amirali Shambayati Bachelor Student Computer Engineering Department Sharif University of Technology Tehran, Iran

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Query about the realtime processes scheduling.
by nilesh Aug. 18, 2011

Aug. 18, 2011

Hi, I am not too familiar with Linux scheduler. What I could understand theoretically is - the interactive processes get advantage (-5) in priority. And hence the effective priority is higher. Query: Is this true for realtime processes ( with SCHED_FIFO/SCHED_RR policy) as well? Could the realtime processes be I/O bound or interactive? -- Thanks, Nilesh

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how to enable linux box to dump crash image on local disk
by amit mehta Aug. 18, 2011

Aug. 18, 2011

I've a Linux box which is crashing under a particular test scenario. To debug this issue I was thinking of using the crash (man 8 crash) utility (available by default on recent releases of RHEL and SuSE) . This tool requires the kernel crash dump (vmcore) and the debugging symbols. On my machine, I don't see any crash under /var/crash, Hence please let me know the configuration changes which i need to do to enable my machine to dump the kernel image locally (do i need to apply diskdump patches and rebuild the kernel??) whenever there is a kernel crash. Kdump seem to be another tool for this job but that requires a lot of setup. Is there a *shortcut* to enable kernel crash dump facility ? The debugging symbols can be found here: http://ftp.riken.go.jp/Linux/slc/slc6X/updates/x86_64/debug/ http://ftp.riken.go.jp/Linux/slc/slc6X/updates/i386/debug/ -Amit

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Thunderbolt and Mac Book Pro
by Greg Freemyer Aug. 17, 2011

Aug. 17, 2011

Can anyone tell me the status of the linux kernel getting Thunderbolt support for the latest Mac Book Pro? I like to carry a boot CD with me that can boot PCs including Macs. I haven't had much issue in the paxt, but apparently the latest Mac Book Pro's are using new technology that is not yet commonly supported. Thanks Greg

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export atomic64_t into /proc/sys/
by LovelyLich Aug. 16, 2011

Aug. 16, 2011

Hello everyone, In my module, there is an atomic64_t counter for something , such as packets received by Ethernet card. What I want to do is to export this atomic64_t number into /proc/sys/net/ipv4/. The question is atomic64_t is an 64-bit long integer which is not support by kernel's default proc_handlers like proc_dointvec(), proc_dointvec_minmax() and so on. So, Do I have to implement one proc_handler to handle this 64-bit integer? Or you have some better ideas? Any reply will be appreciated and Thanks in advanced.

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Re: Dev Environment?
by Mulyadi Santosa Aug. 15, 2011

Aug. 15, 2011

Hi :) On Sun, Aug 14, 2011 at 11:51, Daniel Hilst Selli <danielhilst(a)gmail.com> wrote: > Thanks Mulyadi, I was installing gentoo with qemu.. but takes soo long to > install that I give up, > I was thinking in a minimal distro as dsl or lfs. What you suggest ? Next time, pls keep kernelnewbies list address intact :) About disk image, how about using prebuilt one provided in http://wiki.qemu.org/Download? or ones in http://fs.devloop.org.uk/ ? I think busybox might be a good fit for a tiny setup :) -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com

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Re: Dev Environment?
by Mulyadi Santosa Aug. 15, 2011

Aug. 15, 2011

Hi :) On Mon, Aug 15, 2011 at 11:38, Christophe <kereoz(a)kereoz.org> wrote: > I personally like to debootstrap a Debian and make a qcow2 image from it. You don't need the kernel to be on the image as you can directly pass a kernel to qemu with the -kernel option. I agree, just to add that AFAICT the provided qemu image in the links I mentioned has no kernel image inside them -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com

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Tracing file size changes
by Chris Aug. 15, 2011

Aug. 15, 2011

I'm trying to think of a good way to figure out where space is going on somewhat large and busy filesystems. Often I will be notified by nagios that I am running out of space somewhere, and it will even tell me what the trend in usage is. So now I know that I lost a bunch of space recently. There are several things I can do at that point: - Check quota usage. If quotas are working correctly, this can sometimes help when one user is obviously using a ton of space. More often than not, there is nothing obvious, quotas aren't working or the space is used by system accounts that provide no help in knowing where the space went. - Use du. This is just plain painful and time consuming. Doing this usually causes too much load. Without knowing other ways to find information, I was thinking it would be really nice to have a way to see which files or directories grew or shrank since some point in the past. Would it be possible to get the kernel to tell me when files were opened for writing and closed so I could record the size difference? I know there are various file notify mechanisms, but from what I can see, they don't handle millions of files very well. Of course I'm open to other ideas, but this was my curiosity.

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Purpose of using __be16 inside a data structure?
by 陳國成 Aug. 14, 2011

Aug. 14, 2011

Hi all, Please tell me the difference between using unsigned short and __be16 to declear a variable in a data structure. For example, in include/net/inet_sock.h, struct inet_sock is decleared as struct inet_sock { __be16 inet_dport; }; not struct inet_sock { unsigned short inet_dport; }; I think it has something to do with endianness. But I see that both __le16 and __be16 are unsigned short when using gcc with -E option for little-endian and big-endian platform. Can someone give me more information? * little-endian typedef unsigned short __u16; typedef __u16 __le16; typedef __u16 __be16; * big-endian typedef unsigned short __u16; typedef __u16 __le16; typedef __u16 __be16; Regards, GC

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