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sched: Add new API wake_up_if_idle() to wake up the idle cpu

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

Suggested-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Chuansheng Liu 2014-09-04 15:17:53 +08:00 committed by Ingo Molnar
parent ba7e5a279e
commit f6be8af1c9
2 changed files with 20 additions and 0 deletions
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1
include/linux/sched.h
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@ -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
kernel/sched/core.c
View File

@ -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);