sched: Add new API wake_up_if_idle() to wake up the idle cpu (f6be8af1) · Commits · 戴 / test

Implementing one new API wake_up_if_idle(), which is used to wake up the idle CPU. Suggested-by:

Peter Zijlstra (Intel) <peterz@infradead.org> 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 <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1409815075-4180-1-git-send-email-chuansheng.liu@intel.com Signed-off-by:

include/linux/sched.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -1024,6 +1024,7 @@ struct sched_domain_topology_level {
		extern struct sched_domain_topology_level *sched_domain_topology;

		extern void set_sched_topology(struct sched_domain_topology_level *tl);
		extern void wake_up_if_idle(int cpu);

		#ifdef CONFIG_SCHED_DEBUG
		# define SD_INIT_NAME(type) .name = #type

+19 −0

Original line number	Diff line number	Diff line
		@@ -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);