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authorChuansheng Liu <chuansheng.liu@intel.com>2014-09-04 15:17:53 +0800
committerIngo Molnar <mingo@kernel.org>2014-09-19 12:35:14 +0200
commitf6be8af1c95de4a46e325e728900a70ceadb52cf (patch)
treee9d4d5ef3abe1d341f308688cad4ffa797079bd6 /kernel/sched
parentba7e5a279e72f4b246dc7a419ac707e1936ede3e (diff)
downloadlinux-f6be8af1c95de4a46e325e728900a70ceadb52cf.tar.bz2
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 <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>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/core.c19
1 files changed, 19 insertions, 0 deletions
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);