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: scale sysctl_sched_shares_ratelimit with nr_cpus
  sched: fix rt-bandwidth hotplug race
  sched: fix the race between walk_tg_tree and sched_create_group

kernel/sched.c

@@ -808,9 +808,9 @@ const_debug unsigned int sysctl_sched_nr_migrate = 32;
 
 /*
  * ratelimit for updating the group shares.
- * default: 0.5ms
+ * default: 0.25ms
  */
-const_debug unsigned int sysctl_sched_shares_ratelimit = 500000;
+unsigned int sysctl_sched_shares_ratelimit = 250000;
 
 /*
  * period over which we measure -rt task cpu usage in us.
@@ -5786,6 +5786,8 @@ static inline void sched_init_granularity(void)
 		sysctl_sched_latency = limit;
 
 	sysctl_sched_wakeup_granularity *= factor;
+
+	sysctl_sched_shares_ratelimit *= factor;
 }
 
 #ifdef CONFIG_SMP
@@ -8508,8 +8510,8 @@ struct task_group *sched_create_group(struct task_group *parent)
 	WARN_ON(!parent); /* root should already exist */
 
 	tg->parent = parent;
-	list_add_rcu(&tg->siblings, &parent->children);
 	INIT_LIST_HEAD(&tg->children);
+	list_add_rcu(&tg->siblings, &parent->children);
 	spin_unlock_irqrestore(&task_group_lock, flags);
 
 	return tg;

kernel/sched_rt.c

@@ -298,7 +298,7 @@ static void __disable_runtime(struct rq *rq)
 			struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
 			s64 diff;
 
-			if (iter == rt_rq)
+			if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
 				continue;
 
 			spin_lock(&iter->rt_runtime_lock);