1 files changed, 27 insertions, 13 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index f592ce6f8616..312f8b95c2d4 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2309,7 +2309,7 @@ unsigned long wait_task_inactive(struct task_struct *p, long match_state)
  * Cause a process which is running on another CPU to enter
  * kernel-mode, without any delay. (to get signals handled.)
  *
- * NOTE: this function doesnt have to take the runqueue lock,
+ * NOTE: this function doesn't have to take the runqueue lock,
  * because all it wants to ensure is that the remote task enters
  * the kernel. If the IPI races and the task has been migrated
  * to another CPU then no harm is done and the purpose has been
@@ -4111,20 +4111,20 @@ need_resched:
 					try_to_wake_up_local(to_wakeup);
 			}
 			deactivate_task(rq, prev, DEQUEUE_SLEEP);
+
+			/*
+			 * If we are going to sleep and we have plugged IO queued, make
+			 * sure to submit it to avoid deadlocks.
+			 */
+			if (blk_needs_flush_plug(prev)) {
+				raw_spin_unlock(&rq->lock);
+				blk_schedule_flush_plug(prev);
+				raw_spin_lock(&rq->lock);
+			}
 		}
 		switch_count = &prev->nvcsw;
 	}
 
-	/*
-	 * If we are going to sleep and we have plugged IO queued, make
-	 * sure to submit it to avoid deadlocks.
-	 */
-	if (prev->state != TASK_RUNNING && blk_needs_flush_plug(prev)) {
-		raw_spin_unlock(&rq->lock);
-		blk_flush_plug(prev);
-		raw_spin_lock(&rq->lock);
-	}
-
 	pre_schedule(rq, prev);
 
 	if (unlikely(!rq->nr_running))
@@ -4997,7 +4997,7 @@ recheck:
 	 */
 	raw_spin_lock_irqsave(&p->pi_lock, flags);
 	/*
-	 * To be able to change p->policy safely, the apropriate
+	 * To be able to change p->policy safely, the appropriate
 	 * runqueue lock must be held.
 	 */
 	rq = __task_rq_lock(p);
@@ -5011,6 +5011,17 @@ recheck:
 		return -EINVAL;
 	}
 
+	/*
+	 * If not changing anything there's no need to proceed further:
+	 */
+	if (unlikely(policy == p->policy && (!rt_policy(policy) ||
+			param->sched_priority == p->rt_priority))) {
+
+		__task_rq_unlock(rq);
+		raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+		return 0;
+	}
+
 #ifdef CONFIG_RT_GROUP_SCHED
 	if (user) {
 		/*
@@ -5705,7 +5716,7 @@ void show_state_filter(unsigned long state_filter)
 	do_each_thread(g, p) {
 		/*
 		 * reset the NMI-timeout, listing all files on a slow
-		 * console might take alot of time:
+		 * console might take a lot of time:
 		 */
 		touch_nmi_watchdog();
 		if (!state_filter || (p->state & state_filter))
@@ -6320,6 +6331,9 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
 		break;
 #endif
 	}
+
+	update_max_interval();
+
 	return NOTIFY_OK;
 }