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Date: Mon, 23 Nov 2015 14:05:33 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Lianwei Wang <lianwei.wang@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org,
        rjw@rjwysocki.net, mingo@redhat.com
Subject: Re: [PATCH] sched: idle: move need_resched check after function
 rcu_idle_enter
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References: <CAJFUiJjCcGriSzOZe7BGNb-crrdY5NdUwiWGAO8zM+L_PDr82w@mail.gmail.com>
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On Sat, Nov 21, 2015 at 01:02:02AM -0800, Lianwei Wang wrote:
> The rcu_idle_endter may call wakeup_softirqd to set the need resched
> flag on idle process. But if we don't check it after that, then the
> cpu will enter idle state with RESCHED flag set and can not be woken
> up by wakeup/resched call anymore.

Fair enough; but which cpuidle driver did you observe that with? All the
ones I checked test for need_resched again after this.