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Commit 67b9ca70 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
Browse files

sched/idle: Simplify wake_up_idle_cpu() 



Now that rq->idle's polling bit is a reliable indication that the cpu is
polling, use it.

Signed-off-by: default avatarAndy Lutomirski <luto@amacapital.net>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: nicolas.pitre@linaro.org
Cc: daniel.lezcano@linaro.org
Cc: umgwanakikbuti@gmail.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/922f00761445a830ebb23d058e2ae53956ce2d73.1401902905.git.luto@amacapital.net


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 82c65d60

kernel/sched/core.c

+1 −20
Original line number Diff line number Diff line
@@ -628,26 +628,7 @@ static void wake_up_idle_cpu(int cpu) 
	if (cpu == smp_processor_id())

		return;



	/*

	 * This is safe, as this function is called with the timer

	 * wheel base lock of (cpu) held. When the CPU is on the way

	 * to idle and has not yet set rq->curr to idle then it will

	 * be serialized on the timer wheel base lock and take the new

	 * timer into account automatically.

	 */

	if (rq->curr != rq->idle)

		return;



	/*

	 * We can set TIF_RESCHED on the idle task of the other CPU

	 * lockless. The worst case is that the other CPU runs the

	 * idle task through an additional NOOP schedule()

	 */

	set_tsk_need_resched(rq->idle);



	/* NEED_RESCHED must be visible before we test polling */

	smp_mb();

	if (!tsk_is_polling(rq->idle))

	if (set_nr_and_not_polling(rq->idle))

		smp_send_reschedule(cpu);

	else

		trace_sched_wake_idle_without_ipi(cpu);