Re: [linux-audio-dev] Re: [announce] [patch] Voluntary Kernel Preemption Patch

Ingo Molnar
2004-07-19T12:04:32Z

* Andrea Arcangeli <andrea@suse.de> wrote:

> As Ingo basically showed (and I agree), all current might_sleep seems
> suitable to be converted to cond_resched. I checked all them and
> there's none that seems to be called in a loop for no good reason. the
> ones in the semaphore are quite nice too since it's better to schedule
> right before taking the semaphore than after getting it. The one in
> the semaphore and in the copy-user are the only place where preempt
> seems to be lower overhead but in most other places a spinlock is
> being taken very near to the cond_resched.

yes. Btw., i'm not sure whether you've noticed but last week i've also
created a 'clean' variant of the patch. The latest version against -mm
is:

http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-clean-2.6.7-mm7-H4

this one doesnt have any of the debugging/development helpers and
switches. I have still made it a .config option. Note how minimal the
patch became this way.

Ingo