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Subject: Re: sched: fix/optimise some issues
From: Peter Zijlstra <peterz@infradead.org>
To: stephan.baerwolf@tu-ilmenau.de
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
        ncrao@google.com
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Date: Wed, 20 Jul 2011 21:11:40 +0200
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On Wed, 2011-07-20 at 15:42 +0200, Stephan Bärwolf wrote:
> 
> The function "check_preempt_wakeup" (kernel/sched_fair.c:1885)
> will preempt idle-task (for non-idle task), even if WAKEUP_PREEMPT
> is not featured (because of a too late checking the feature).
> This patches moves the checking of WAKEUP_PREEMT in front of
> idle-preemtion. 

That's actually on purpose, the WAKE_PREEMPT feature is supposed to only
affect preemption between SCHED_OTHER tasks.