From f6be8af1c95de4a46e325e728900a70ceadb52cf Mon Sep 17 00:00:00 2001 From: Chuansheng Liu Date: Thu, 4 Sep 2014 15:17:53 +0800 Subject: sched: Add new API wake_up_if_idle() to wake up the idle cpu Implementing one new API wake_up_if_idle(), which is used to wake up the idle CPU. Suggested-by: Andy Lutomirski Signed-off-by: Chuansheng Liu Signed-off-by: Peter Zijlstra (Intel) Cc: daniel.lezcano@linaro.org Cc: rjw@rjwysocki.net Cc: linux-pm@vger.kernel.org Cc: changcheng.liu@intel.com Cc: xiaoming.wang@intel.com Cc: souvik.k.chakravarty@intel.com Cc: chuansheng.liu@intel.com Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1409815075-4180-1-git-send-email-chuansheng.liu@intel.com Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'kernel') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 78e5c839df13..f7c6ed2fd69d 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1634,6 +1634,25 @@ static void ttwu_queue_remote(struct task_struct *p, int cpu) } } +void wake_up_if_idle(int cpu) +{ + struct rq *rq = cpu_rq(cpu); + unsigned long flags; + + if (!is_idle_task(rq->curr)) + return; + + if (set_nr_if_polling(rq->idle)) { + trace_sched_wake_idle_without_ipi(cpu); + } else { + raw_spin_lock_irqsave(&rq->lock, flags); + if (is_idle_task(rq->curr)) + smp_send_reschedule(cpu); + /* Else cpu is not in idle, do nothing here */ + raw_spin_unlock_irqrestore(&rq->lock, flags); + } +} + bool cpus_share_cache(int this_cpu, int that_cpu) { return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); -- cgit v1.2.3-59-g8ed1b