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Subject: Re: [tip:sched/urgent] Sched: fix skip_clock_update optimization
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Yong Zhang <yong.zhang0@gmail.com>
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Date: Fri, 10 Dec 2010 17:17:48 +0100
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On Fri, 2010-12-10 at 10:33 +0800, Yong Zhang wrote:
> 
> I don't see it on my side.
> Then just show some info(don't know if it's helpful):
> wake_up_idle_cpu() can set TIF_RESCHED locklessly.
> 
> So does
> WARN_ON_ONCE(next != rq->idle && test_tsk_need_resched(next));
> help?

Its a good possibility, sadly I haven't been able to reproduce so I
cannot confirm. I'll keep my machine running, maybe it will trigger in a
few hours.