sched: Revert commit 4c6c4e3 ("sched/core: Fix endless loop in pick_n…

…ext_task()")

This reverts commit 4c6c4e3 ("sched/core: Fix endless loop in
pick_next_task()"), which is not necessary after ("sched/rt: Substract number
of tasks of throttled queues from rq->nr_running").

Signed-off-by: Kirill Tkhai <tkhai@yandex.ru>
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
[conflict resolution with stop task checking patch]
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1394835307.18748.34.camel@HP-250-G1-Notebook-PC
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/fair.c

@@ -6732,10 +6732,7 @@ static int idle_balance(struct rq *this_rq)
 
 out:
 	/* Is there a task of a high priority class? */
-	if (this_rq->nr_running != this_rq->cfs.h_nr_running &&
-	    ((this_rq->stop && this_rq->stop->on_rq) ||
-	     this_rq->dl.dl_nr_running ||
-	     (this_rq->rt.rt_nr_running && !rt_rq_throttled(&this_rq->rt))))
+	if (this_rq->nr_running != this_rq->cfs.h_nr_running)
 		pulled_task = -1;
 
 	if (pulled_task) {

kernel/sched/rt.c

@@ -493,6 +493,11 @@ static void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
 		dequeue_rt_entity(rt_se);
 }
 
+static inline int rt_rq_throttled(struct rt_rq *rt_rq)
+{
+	return rt_rq->rt_throttled && !rt_rq->rt_nr_boosted;
+}
+
 static int rt_se_boosted(struct sched_rt_entity *rt_se)
 {
 	struct rt_rq *rt_rq = group_rt_rq(rt_se);
@@ -569,6 +574,11 @@ static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
 	dequeue_top_rt_rq(rt_rq);
 }
 
+static inline int rt_rq_throttled(struct rt_rq *rt_rq)
+{
+	return rt_rq->rt_throttled;
+}
+
 static inline const struct cpumask *sched_rt_period_mask(void)
 {
 	return cpu_online_mask;

kernel/sched/sched.h

@@ -425,18 +425,6 @@ struct rt_rq {
 #endif
 };
 
-#ifdef CONFIG_RT_GROUP_SCHED
-static inline int rt_rq_throttled(struct rt_rq *rt_rq)
-{
-	return rt_rq->rt_throttled && !rt_rq->rt_nr_boosted;
-}
-#else
-static inline int rt_rq_throttled(struct rt_rq *rt_rq)
-{
-	return rt_rq->rt_throttled;
-}
-#endif
-
 /* Deadline class' related fields in a runqueue */
 struct dl_rq {
 	/* runqueue is an rbtree, ordered by deadline */