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Date: Fri, 10 Jul 2009 17:24:27 +0200
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()
Message-ID: <20090710152425.GB5318@nowhere>
References: <1247237391-5352-1-git-send-email-fweisbec@gmail.com> <200907101717.39460.arnd@arndb.de>
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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?