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 f592ce6f8616..a8845516ace6 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 3f7ec9e27ee1..c7ec5c8e7b44 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;