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);