2 files changed, 24 insertions, 0 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 1ff9e0a5de27..a74adedcdd10 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1856,6 +1856,12 @@ extern void wake_up_nohz_cpu(int cpu);
 static inline void wake_up_nohz_cpu(int cpu) { }
 #endif
 
+#ifdef CONFIG_NO_HZ_FULL
+extern bool sched_can_stop_tick(void);
+#else
+static inline bool sched_can_stop_tick(void) { return false; }
+#endif
+
 #ifdef CONFIG_SCHED_AUTOGROUP
 extern void sched_autogroup_create_attach(struct task_struct *p);
 extern void sched_autogroup_detach(struct task_struct *p);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 0f0a5b3fd62c..69f71335984f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -650,6 +650,24 @@ static inline bool got_nohz_idle_kick(void)
 
 #endif /* CONFIG_NO_HZ_COMMON */
 
+#ifdef CONFIG_NO_HZ_FULL
+bool sched_can_stop_tick(void)
+{
+       struct rq *rq;
+
+       rq = this_rq();
+
+       /* Make sure rq->nr_running update is visible after the IPI */
+       smp_rmb();
+
+       /* More than one running task need preemption */
+       if (rq->nr_running > 1)
+               return false;
+
+       return true;
+}
+#endif /* CONFIG_NO_HZ_FULL */
+
 void sched_avg_update(struct rq *rq)
 {
         s64 period = sched_avg_period();