Re: INGO Why you remove set_user_nice() from kernel/kthread.c

From: Mike Galbraith
Date: Mon Sep 14 2009 - 10:05:49 EST


If you're asking Ingo a question, maybe a CC is in order.

On Mon, 2009-09-14 at 17:42 +0400, Pavel Vasilyev wrote:
>
> Next patÑh -
> http://www.kernel.org/diff/diffview.cgi?file=%2Fpub%2Flinux%2Fkernel%2F%2Fv2.6%2Fsnapshots%2Fpatch-2.6.31-git2.bz2;z=548
>
> This patch defines the core processes that are working with nice leve equal to
> zero , as in the BFS. :)
>
> Why?

I did that, not Ingo, and did so because with kthreads that use
diddly-spit CPU (every one I see), it's just a waste of math. What
kthreads are you seeing using so much CPU that their weight is a factor?
They _should_ be able to preempt and get their work done just fine
without a boost.

> VirtualBox, Vmware, QEMU, Firefox, Azureus, and many subsystems and
> applications began working with large timeouts. In appearance similar to
> hang.

In any case, if it's causing problems, reverting is easy enough, though
better would be to find out the why.

-Mike


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