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

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Fix lockup by limiting load-balance retries on lock-break
  sched: Fix CONFIG_CGROUP_SCHED dependency
  sched: Remove empty #ifdefs

init/Kconfig

@@ -713,7 +713,6 @@ config CGROUP_PERF
 
 menuconfig CGROUP_SCHED
 	bool "Group CPU scheduler"
-	depends on EXPERIMENTAL
 	default n
 	help
 	  This feature lets CPU scheduler recognize task groups and control CPU

kernel/sched/core.c

@@ -7134,10 +7134,6 @@ void set_curr_task(int cpu, struct task_struct *p)
 
 #endif
 
-#ifdef CONFIG_RT_GROUP_SCHED
-#else /* !CONFIG_RT_GROUP_SCHED */
-#endif /* CONFIG_RT_GROUP_SCHED */
-
 #ifdef CONFIG_CGROUP_SCHED
 /* task_group_lock serializes the addition/removal of task groups */
 static DEFINE_SPINLOCK(task_group_lock);
@@ -7246,9 +7242,6 @@ void sched_move_task(struct task_struct *tsk)
 }
 #endif /* CONFIG_CGROUP_SCHED */
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
-#endif
-
 #if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH)
 static unsigned long to_ratio(u64 period, u64 runtime)
 {

kernel/sched/fair.c

@@ -3130,8 +3130,10 @@ task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
 }
 
 #define LBF_ALL_PINNED	0x01
-#define LBF_NEED_BREAK	0x02
-#define LBF_ABORT	0x04
+#define LBF_NEED_BREAK	0x02	/* clears into HAD_BREAK */
+#define LBF_HAD_BREAK	0x04
+#define LBF_HAD_BREAKS	0x0C	/* count HAD_BREAKs overflows into ABORT */
+#define LBF_ABORT	0x10
 
 /*
  * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
@@ -4508,7 +4510,9 @@ static int load_balance(int this_cpu, struct rq *this_rq,
 			goto out_balanced;
 
 		if (lb_flags & LBF_NEED_BREAK) {
-			lb_flags &= ~LBF_NEED_BREAK;
+			lb_flags += LBF_HAD_BREAK - LBF_NEED_BREAK;
+			if (lb_flags & LBF_ABORT)
+				goto out_balanced;
 			goto redo;
 		}