On 9/7/05, Kristis Makris <mkgnu@xxxxxxx> wrote:
> Hello,
>
> I'm trying to kill a kernel thread gracefully, in particular kswapd,
> without any success.
>
> The goal is to start another kernel thread that contains updated kswapd
> functionality, through a loadable module; no kernel recompilation.
>
> I noticed that kernel threads block SIGKILL. Hence, on module load I'm
> running:
>
> task = find_task_by_name("kswapd");
> if (task != NULL) {
> spin_lock_irq(&task->sigmask_lock);
> sigdelset(&task->blocked, SIGKILL);
> recalc_sigpending(task);
> spin_unlock_irq(&task->sigmask_lock);
> // Also tried issuing here a: kill_proc(task->pid, SIGKILL, 1);
> }
>
> Then from userspace I issue:
>
> # ps aux |grep -i swap
> root 4 0.0 0.0 0 0 ? SW 18:36 0:00 [kswapd]
> $ kill -9 4
>
> After the kill is issued, kswapd taking up 99.9% of CPU time and remains
> at a runnable state:
> # ps aux |grep -i swap
> root 4 0.2 0.0 0 0 ? RW 18:36 0:02 [kswapd]
>
>
> Can anyone explain why this is happening ? I've tried this with linux
> kernels 2.2.19 and 2.4.27 (with patch kdb-4.3).
I don't think that kswapd can be killed by loading modules or after
when it started during boot time ..... As I havn't saw any break or
getting kill or other signals in the code of kswapd, this means that
when it goes into for(;;) loop it won't break out of it through any
killing signal send from outside. I may be wrong b/c I havn't worked
on it but telling what I can get by just seeing on the code of kswapd
fucntion.
> What is the proper way of gracefully killing a kernel thread launched from the original kernel
> image (not a module) in kernels < 2.6 (ie. without the new kernel thread
> API that contains the stop_kthread call from
> http://www.scs.ch/~frey/linux/kernelthreads.html)
>
I m not able to understand what you want to ask !!!!
--
Fawad Lateef
--
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