Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: Fix rebalance interval calculation
  sched, doc: Beef up load balancing description
  sched: Leave sched_setscheduler() earlier if possible, do not disturb SCHED_FIFO tasks

2 files changed, 14 insertions, 2 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index f592ce6..a884551 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -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) {
 		/*
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 3f7ec9e..c7ec5c8 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -22,6 +22,7 @@
 
 #include <linux/latencytop.h>
 #include <linux/sched.h>
+#include <linux/cpumask.h>
 
 /*
  * Targeted preemption latency for CPU-bound tasks:
@@ -3850,8 +3851,8 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle)
 		interval = msecs_to_jiffies(interval);
 		if (unlikely(!interval))
 			interval = 1;
-		if (interval > HZ*NR_CPUS/10)
-			interval = HZ*NR_CPUS/10;
+		if (interval > HZ*num_online_cpus()/10)
+			interval = HZ*num_online_cpus()/10;
 
 		need_serialize = sd->flags & SD_SERIALIZE;