Merge branch 'sched/urgent' into sched/core, to pick up fixes before applying new...

[firefly-linux-kernel-4.4.55.git] / kernel / sched / core.c

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 62671f53202ac7d4de8037dce950c934c7a4ddbc..feda520bd0348f73a5f76f3e9e5a7d06e811657d 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -689,6 +689,23 @@ static inline bool got_nohz_idle_kick(void)
 #ifdef CONFIG_NO_HZ_FULL
 bool sched_can_stop_tick(void)
 {
+       /*
+        * FIFO realtime policy runs the highest priority task. Other runnable
+        * tasks are of a lower priority. The scheduler tick does nothing.
+        */
+       if (current->policy == SCHED_FIFO)
+               return true;
+
+       /*
+        * Round-robin realtime tasks time slice with other tasks at the same
+        * realtime priority. Is this task the only one at this priority?
+        */
+       if (current->policy == SCHED_RR) {
+               struct sched_rt_entity *rt_se = &current->rt;
+
+               return rt_se->run_list.prev == rt_se->run_list.next;
+       }
+
        /*
         * More than one running task need preemption.
         * nr_running update is assumed to be visible