Everything about UNIX kernels: development, configuration, compilation, design, etc.

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1answer
634 views

Does IO prioritise by the very nature of renicing a task?

The CFQ IO scheduler supports priorities though I am not sure that Deadline does (I believe not). The premise is that when I renice a task it gets a larger share of CPU under the Completely Fair ...
9
votes
6answers
17k views

How does a kernel mount the root partition?

My question is with regards to booting a Linux system from a separate /boot partition. If most configuration files are located on a separate / partition, how does the kernel correctly mount it at boot ...
2
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1answer
1k views

Where is CONFIG_COMPAT_VDSO in make menuconfig?

I'm trying to compile a Linux Kernel to run light and paravirtualized on XenServer 5.6 fp1. I'm using the guide given here: ...
7
votes
1answer
218 views

How's a module approved to be included into the linux kernel?

I'm now compiling the linux kernel 2.6, and finding there are more than 1,000 modules in total. How is a module approved to be included into the linux kernel?
4
votes
1answer
342 views

NetBSD 5.1 NDIS Kernel Compile Error

I have an old Toshiba Satellite 4015CDT, with Pentium II MMX, 32MB RAM, 4GB HDD. It also has one USB 1.0 port, parallel and serial ports, a 3.5" floppy drive and a CD-ROM drive (almost dead). I've ...
3
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2answers
4k views

Numbering convention for the linux kernel?

What is the convention for numbering the linux kernels? AFAIK, the numbers never seem to decrease. However, i think I've seen three kinds of schemes 2.6.32-29 2.6.32-29.58 2.6.11.10 Can anybody ...
7
votes
1answer
3k views

Can new glibc versions be used with an old kernel?

Apparently glibc can be compiled with --enable-kernel to support older kernel versions. However, I haven't been able to find information on what kernel versions are supported on a particular glibc ...
2
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1answer
210 views

Why is bzip2 needed in the kernel patch instructions?

This is from here. Extract the patch tar -xvzf /usr/src/web100-2.5.22-200810130047.tar.gz bzip2 web100/ web100-2.6.27-2.5.22-200810130047.patch Test the patch bzip2 -dc /usr/src/linux/web100/ ...
2
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1answer
1k views

Dump Page table layout (KERNEL CONFIG)

While configuring kernel for debugging found this option: CONFIG_X86_PTDUMP: Export kernel pagetable layout to userspace via debugfs Does this mean RAM page-table layouts ? any guides on how ...
2
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1answer
967 views

Where can I find information on Linux device driver parameters?

I want to work on Linux module programming (Device Drivers). And as a my college project I have to do profiling or benchmarking of a kernel modules based on various parameters. Everywhere I looked, I ...
4
votes
1answer
1k views

Booting without initrd

Is it possible to boot linux without a initrd.img ? I am planning to add default drivers as a part-of-kernel itself and avoid initrd completely. What are the modules that should be made ...
2
votes
1answer
1k views

Creating new initrd without installing kernel

How can i create initrd image for a new(experimental) kernel without actually installing it. (Existing tools to create initrd based on config and details from installed kernel.) Say i compile a new ...
9
votes
3answers
744 views

Memory size for kernel mmap operation

I'm interested in the way Linux mmaps files into the main memory (in my context its for executing, but I guess the mmap process is the same for writing and reading as well) and which size it uses. So ...
22
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4answers
3k views

Kernel Hacking Environment

I have been working in embedded OS like uCOS, ThreadX. While I have coded apps in Linux, now I’m planning to start learning Linux Kernel. I have few questions regarding the environment. Which is ...
4
votes
1answer
1k views

How to use the EXTRA_FIRMWARE_DIR kernel option?

I am using Gentoo, and I need to load an extra firmware to get my USB Wifi adapter work. I found an EXTRA_FIRMWARE_DIR kernel option, but I do not understand if it is used during compile time only or ...
4
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2answers
1k views

Benefiting of sched_autogroup_enabled on the desktop

I am running a 2.6.37 kernel with sched_autogroup_enabled set to 1. I am not certain that I am seeing the benefits of this patch since: I am launching my applications from the desktop; applications ...
3
votes
1answer
311 views

Linux kernel support for USB gamepads?

I've got an old Logitech USB gamepad that worked well under both Windows and Mac OS X. That is, the gamepad was totally "plug and play" for games run by a Super Nintendo emulator (SNES9X). Does Linux ...
3
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2answers
437 views

What are the kernel, the “GNU tools and utilities”, the shell and the Window Manager?

Among the many components of a Linux system, I find myself confused (as a newbie) about what exactly is the kernel or what is GNU's part. I understand some basic concepts of this, but where is the ...
2
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1answer
6k views

RAMDISK incomplete write error kernel panic

I am building Linux Kernel 2.6.36.4 on a Dell Laptop which has Linux Kernel 2.6.35.11 running. BTW I got the source from kernel.org. The source had few syntax errors which I fixed in the process and ...
1
vote
1answer
2k views

How to view and change kernel memory size?

How can i view the kernel's share of memory on a machine? How can I increase it? What should I consider before doing it?
26
votes
1answer
2k views

Why isn't a straightforward 1/5/15 minute moving average used in Linux load calculation?

Until recently i thought the load average (as shown for example in top) was a moving average on the n last values of the number of process in state "runnable" or "running". And n would have been ...
1
vote
1answer
482 views

How can I use my server to compile a kernel for my laptop?

My laptop, an HP pavilion with an nVidia card, has some issues with suspending. Namely firewire breaks on suspend and the nvidia drivers cause Xorg to hang on resume. I'd like to compile my own kernel ...
2
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2answers
1k views

no network device found after Kernel update

So I managed to install Debian 5 on an eBox 3300MX (an embedded type computer). I added a custom kernel after getting a basic install done. That was to get the network card to work. After that, I ...
9
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1answer
6k views

Unable to handle kernel paging request?

[Disclaimer: I was initially a little nervous about posting this here, so I asked on Meta if discussing homebrew / modding was acceptable. Based on the response I've gotten from several veteran ...
2
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1answer
184 views

Add latency when accessing certain websites under linux

I've been playing with tc on my local machine. sudo tc qdisc add dev eth0 root netem delay 2000ms adds a 2-second latency to all traffic going through eth0. What I want is to be able to limit this ...
13
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4answers
3k views

Read the stack of another process?

I'm trying to read a child process's stack but with no luck. I know it is possible using ptrace, but ptrace's interface allows you to read only one word at a time, and I'm trying to scan a larger ...
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0answers
286 views

error booting the custom compiled kernel 2.6.37 on ubuntu 10.04 : gave up waiting on root device [duplicate]

Possible Duplicate: Kernel can't find /dev/sda file during boot Hi, I know this is very common problem and there are many threads discussing it. However after trying many solutions ...
3
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2answers
425 views

How do I profile the kernel?

I'm having issues with a kworker process during system boot and I'd like to get such a nice call graph like Linus Torvalds posted here. How would I do this?
4
votes
2answers
314 views

“Linux supports the dynamic loading of kernel modules. ”

I read in a book written by Robert Love that: Linux supports the dynamic loading of kernel modules. He said this is the difference between Linux and Unix, but I seem to recall there is also KLD ...
3
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3answers
1k views

Book on Linux kernel driver development [closed]

What good books are there out there for Linux kernel driver development? Preferably targeting a rather new kernel release. Which one is best in you opinion? Essential Linux Device Drivers Linux ...
5
votes
2answers
400 views

Which kernel does reboot load?

I am using ssh to remotely access some machines. These machines have a custom kernel installed (based on the 2.6.28 source). However, whenever I try to reboot the machines using sudo reboot, the ...
5
votes
1answer
3k views

Hung system call

So I'm working with a custom kernel module that I'm writing a python front end for. The kernel module works, and it adds a framebuffer device file to /dev/fb1. I can read and write to it fine. I've ...
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3answers
3k views

Implications of Linux support for AMD Fusion APUs?

As I understand it, the Linux kernel has had good support for Intel and AMD CPUs (pretty obvious since your OS installs and runs fine!). But now that AMD is releasing their new Fusion APUs, is it ...
4
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3answers
2k views

'fast interrupts' in Linux

as far as I know, Linux has 'fast interrupts', those that were requested with SA_INTERRUPT flag; fast interrupts are executed with all other interrupts disabled on the current CPU. But how does it ...
3
votes
2answers
2k views

re-entrency of interrupts in Linux

I was reading "Linux device drivers, 3rd edition" and don't completely understand a part describing interrupt handlers. I would like to clarify: are the interrupt handlers in Linux nonpreemptible? ...
4
votes
3answers
717 views

Preloading the OOM Killer

I don't have any swap partition/file on my machine, and only 2GB of RAM. Sometimes it happens that the memory gets saturated by some process (Xorg+browser+compiler+...) and the system hangs ...
24
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1answer
34k views

How is a message queue implemented in the Linux kernel?

I would like to know how Message Queues are implemented in the Linux Kernel.
15
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4answers
543 views

How do I learn what I can do with /proc and /sys

I'd like to know more about the advanced uses of the /proc and /sys virtual filesystems, but I don't know where to begin. Can anyone suggest any good sources to learn from? Also, since I think sys has ...
0
votes
2answers
345 views

FreeBSD's kernel is 'locked'?

I happened to talk to a Mac Genius on the subject of viruses. He mentioned that the FreeBSD kernel on which the Mac OS is based is 'locked' and therefore no viruses can ever harm my Mac. I didn't ...
2
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2answers
966 views

Questions on Linux kernel internals [closed]

I was reading "Linux device drivers, 3rd edition" and faced a few kernel items I don't quite understand. Hope gurus on this forum will help me out. Does the Linux kernel internally operate with ...
8
votes
2answers
2k views

How do I debug a kernel module in which a NULL pointer appears?

I have a custom kernel module that I compiled from this patch that adds support for the logitech G19 keyboard among other G series devices. I compiled it just fine against Ubuntu's maverick kernel's ...
4
votes
1answer
368 views

Changes to input_get_keycode function in linux kernel (input/input.c)

I'm working on building a kernel module for an input device, and I noticed that in the module source, there's a couple calls to input_get_keycode(data->input_dev, scancode, &keycode); When I ...
1
vote
2answers
843 views

S3 sleep problems — nVidia or Intel H67 (Sandy Bridge motherboard) issue?

I have a new Sandy Bridge i5-2500 and Intel H67 motherboard. As the onboard video didn't work, I put in an older 8600 gts graphics card. However, the S3 suspend won't work (and I can't test without ...
14
votes
5answers
12k views

Use of O_DIRECT on Linux

If this question is too programmer oriented, let me know. I wonder if there are people familiar with the O_DIRECT flag for the open() system call on Linux 2.6? Linus disparages its use, however high ...
25
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8answers
9k views

How does Linux kernel compare to microkernel architectures?

I read once that one advantage of a microkernel architecture is that you can stop/start essential services like networking and filesystems, without needing to restart the whole system. But considering ...
91
votes
4answers
57k views

How do I read from /proc/$pid/mem under Linux?

The Linux proc(5) man page tells me that /proc/$pid/mem “can be used to access the pages of a process's memory”. But a straightforward attempt to use it only gives me $ cat /proc/$$/mem ...
3
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1answer
280 views

Can't shutdown mandriva 2010.2

I can't seem to shutdown my machine from mandriva,I have to restart to shut it down from GRUB it says "System Halted" and just freezes there I'm using the x86_64 GNOME version I've already asked on ...
1
vote
1answer
746 views

Select YeAH-TCP like congestion control algorithm to configure kernel

I'm configuring/compiling the 2.6.37 kernel and I want select YeAH-TCP like default congestion control algorithm but, although I enable this option (CONFIG_TCP_CONG_YEAH), it doesn't show in the ...
5
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1answer
2k views

Usage of inb, inl, inw to access kernel space from user space

What are some user space examples of using inb, inl, and inw to access kernel space in Linux?
5
votes
1answer
309 views

Why do I need ntfs-3g when I have already enabled NTFS support in the kernel?

When configuring the kernel I see an option to add read-write support for NTFS. Then when mounting my NTFS partition I still have to install ntfs-3g and pass ntfs-3g as the type. I thought if I add ...