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Commit f6be8af1 authored by Chuansheng Liu's avatar Chuansheng Liu Committed by Ingo Molnar
Browse files

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: default avatarAndy Lutomirski <luto@amacapital.net>
Signed-off-by: default avatarChuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: default avatarPeter 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: default avatarIngo Molnar <mingo@kernel.org>
parent ba7e5a27

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

kernel/sched/core.c

+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);