sched/fair: Fix reschedule which is generated on throttled cfs_rq

(sched_entity::on_rq == 1) does not guarantee the task is pickable;
changes on throttled cfs_rq must not lead to reschedule.

Check for task_struct::on_rq instead.

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1407312361.8424.35.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 1413c44ce8a1aef666c3fd004aee954a2e810f0b..bc37bb97159f322967e9b73200b4cea5cac6aa97 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7494,7 +7494,7 @@ static void task_fork_fair(struct task_struct *p)
 static void
 prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
 {
-       if (!p->se.on_rq)
+       if (!p->on_rq)
                return;
 
        /*
@@ -7550,15 +7550,15 @@ static void switched_from_fair(struct rq *rq, struct task_struct *p)
  */
 static void switched_to_fair(struct rq *rq, struct task_struct *p)
 {
-       struct sched_entity *se = &p->se;
 #ifdef CONFIG_FAIR_GROUP_SCHED
+       struct sched_entity *se = &p->se;
        /*
         * Since the real-depth could have been changed (only FAIR
         * class maintain depth value), reset depth properly.
         */
        se->depth = se->parent ? se->parent->depth + 1 : 0;
 #endif
-       if (!se->on_rq)
+       if (!p->on_rq)
                return;
 
        /*