From 67b9ca70c3030e832999e8d1cdba2984c7bb5bfc Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Wed, 4 Jun 2014 10:31:17 -0700 Subject: [PATCH] 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: Andy Lutomirski Signed-off-by: Peter Zijlstra Cc: Rafael J. Wysocki Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: umgwanakikbuti@gmail.com Cc: Linus Torvalds Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/922f00761445a830ebb23d058e2ae53956ce2d73.1401902905.git.luto@amacapital.net Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 21 +-------------------- 1 file changed, 1 insertion(+), 20 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index e4c0ddd..6afbfee 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -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); -- 2.7.4