From: Frederic Weisbecker <fweisbec@gmail.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH 1/2] sched: Drop the need_resched() loop from cond_resched()
Date: Fri, 10 Jul 2009 17:24:27 +0200 [thread overview]
Message-ID: <20090710152425.GB5318@nowhere> (raw)
In-Reply-To: <200907101717.39460.arnd@arndb.de>
On Fri, Jul 10, 2009 at 05:17:38PM +0200, Arnd Bergmann wrote:
> On Friday 10 July 2009, Frederic Weisbecker wrote:
> > --- a/kernel/sched.c
> > +++ b/kernel/sched.c
> > @@ -6613,11 +6613,9 @@ static void __cond_resched(void)
> > * PREEMPT_ACTIVE, which could trigger a second
> > * cond_resched() call.
> > */
> > - do {
> > - add_preempt_count(PREEMPT_ACTIVE);
> > - schedule();
> > - sub_preempt_count(PREEMPT_ACTIVE);
> > - } while (need_resched());
> > + add_preempt_count(PREEMPT_ACTIVE);
> > + schedule();
> > + sub_preempt_count(PREEMPT_ACTIVE);
> > }
> >
>
> If you drop the loop, then you should also remove the comment that
> explains why it was put there.
>
> Arnd <><
Hmm, these comments seem to actually explain why we do the PREEMPT_ACTIVE
trick, which is to prevent from cond_resched() recursion, right?
next prev parent reply other threads:[~2009-07-10 15:24 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-10 14:49 [PATCH 1/2] sched: Drop the need_resched() loop from cond_resched() Frederic Weisbecker
2009-07-10 14:49 ` [PATCH 2/2] sched: Move the sleeping while atomic checks early in cond_resched() Frederic Weisbecker
2009-07-10 14:59 ` Peter Zijlstra
2009-07-10 15:08 ` Frederic Weisbecker
2009-07-10 15:12 ` Peter Zijlstra
2009-07-10 16:10 ` Ingo Molnar
2009-07-10 17:14 ` [PATCH] " Frederic Weisbecker
2009-07-10 17:43 ` Peter Zijlstra
2009-07-10 18:08 ` Frederic Weisbecker
2009-07-10 18:13 ` Peter Zijlstra
2009-07-10 18:29 ` Frederic Weisbecker
2009-07-10 15:00 ` [PATCH 1/2] sched: Drop the need_resched() loop from cond_resched() Peter Zijlstra
2009-07-10 15:17 ` Arnd Bergmann
2009-07-10 15:24 ` Frederic Weisbecker [this message]
2009-07-10 15:35 ` Arnd Bergmann
2009-07-10 15:50 ` Frederic Weisbecker
2009-07-10 16:11 ` Ingo Molnar
2009-07-10 16:26 ` Frederic Weisbecker
2009-07-10 17:23 ` [PATCH] sched: Remove obsolete comment in __cond_resched() Frederic Weisbecker
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