Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

1 files changed, 360 insertions, 134 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 3eedd5260907..f28f19e65b59 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -155,7 +155,7 @@ struct rt_prio_array {
 	struct list_head queue[MAX_RT_PRIO];
 };
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_GROUP_SCHED
 
 #include <linux/cgroup.h>
 
@@ -165,19 +165,16 @@ static LIST_HEAD(task_groups);
 
 /* task group related information */
 struct task_group {
-#ifdef CONFIG_FAIR_CGROUP_SCHED
+#ifdef CONFIG_CGROUP_SCHED
 	struct cgroup_subsys_state css;
 #endif
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
 	/* schedulable entities of this group on each cpu */
 	struct sched_entity **se;
 	/* runqueue "owned" by this group on each cpu */
 	struct cfs_rq **cfs_rq;
 
-	struct sched_rt_entity **rt_se;
-	struct rt_rq **rt_rq;
-
-	unsigned int rt_ratio;
-
 	/*
 	 * shares assigned to a task group governs how much of cpu bandwidth
 	 * is allocated to the group. The more shares a group has, the more is
@@ -213,33 +210,46 @@ struct task_group {
 	 *
 	 */
 	unsigned long shares;
+#endif
+
+#ifdef CONFIG_RT_GROUP_SCHED
+	struct sched_rt_entity **rt_se;
+	struct rt_rq **rt_rq;
+
+	u64 rt_runtime;
+#endif
 
 	struct rcu_head rcu;
 	struct list_head list;
 };
 
+#ifdef CONFIG_FAIR_GROUP_SCHED
 /* Default task group's sched entity on each cpu */
 static DEFINE_PER_CPU(struct sched_entity, init_sched_entity);
 /* Default task group's cfs_rq on each cpu */
 static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp;
 
-static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity);
-static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp;
-
 static struct sched_entity *init_sched_entity_p[NR_CPUS];
 static struct cfs_rq *init_cfs_rq_p[NR_CPUS];
+#endif
+
+#ifdef CONFIG_RT_GROUP_SCHED
+static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity);
+static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp;
 
 static struct sched_rt_entity *init_sched_rt_entity_p[NR_CPUS];
 static struct rt_rq *init_rt_rq_p[NR_CPUS];
+#endif
 
-/* task_group_mutex serializes add/remove of task groups and also changes to
+/* task_group_lock serializes add/remove of task groups and also changes to
  * a task group's cpu shares.
  */
-static DEFINE_MUTEX(task_group_mutex);
+static DEFINE_SPINLOCK(task_group_lock);
 
 /* doms_cur_mutex serializes access to doms_cur[] array */
 static DEFINE_MUTEX(doms_cur_mutex);
 
+#ifdef CONFIG_FAIR_GROUP_SCHED
 #ifdef CONFIG_SMP
 /* kernel thread that runs rebalance_shares() periodically */
 static struct task_struct *lb_monitor_task;
@@ -248,35 +258,40 @@ static int load_balance_monitor(void *unused);
 
 static void set_se_shares(struct sched_entity *se, unsigned long shares);
 
+#ifdef CONFIG_USER_SCHED
+# define INIT_TASK_GROUP_LOAD	(2*NICE_0_LOAD)
+#else
+# define INIT_TASK_GROUP_LOAD	NICE_0_LOAD
+#endif
+
+#define MIN_GROUP_SHARES	2
+
+static int init_task_group_load = INIT_TASK_GROUP_LOAD;
+#endif
+
 /* Default task group.
  *	Every task in system belong to this group at bootup.
  */
 struct task_group init_task_group = {
+#ifdef CONFIG_FAIR_GROUP_SCHED
 	.se	= init_sched_entity_p,
 	.cfs_rq = init_cfs_rq_p,
+#endif
 
+#ifdef CONFIG_RT_GROUP_SCHED
 	.rt_se	= init_sched_rt_entity_p,
 	.rt_rq	= init_rt_rq_p,
-};
-
-#ifdef CONFIG_FAIR_USER_SCHED
-# define INIT_TASK_GROUP_LOAD	(2*NICE_0_LOAD)
-#else
-# define INIT_TASK_GROUP_LOAD	NICE_0_LOAD
 #endif
-
-#define MIN_GROUP_SHARES	2
-
-static int init_task_group_load = INIT_TASK_GROUP_LOAD;
+};
 
 /* return group to which a task belongs */
 static inline struct task_group *task_group(struct task_struct *p)
 {
 	struct task_group *tg;
 
-#ifdef CONFIG_FAIR_USER_SCHED
+#ifdef CONFIG_USER_SCHED
 	tg = p->user->tg;
-#elif defined(CONFIG_FAIR_CGROUP_SCHED)
+#elif defined(CONFIG_CGROUP_SCHED)
 	tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id),
 				struct task_group, css);
 #else
@@ -288,21 +303,15 @@ static inline struct task_group *task_group(struct task_struct *p)
 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
 static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
 {
+#ifdef CONFIG_FAIR_GROUP_SCHED
 	p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
 	p->se.parent = task_group(p)->se[cpu];
+#endif
 
+#ifdef CONFIG_RT_GROUP_SCHED
 	p->rt.rt_rq  = task_group(p)->rt_rq[cpu];
 	p->rt.parent = task_group(p)->rt_se[cpu];
-}
-
-static inline void lock_task_group_list(void)
-{
-	mutex_lock(&task_group_mutex);
-}
-
-static inline void unlock_task_group_list(void)
-{
-	mutex_unlock(&task_group_mutex);
+#endif
 }
 
 static inline void lock_doms_cur(void)
@@ -318,12 +327,10 @@ static inline void unlock_doms_cur(void)
 #else
 
 static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
-static inline void lock_task_group_list(void) { }
-static inline void unlock_task_group_list(void) { }
 static inline void lock_doms_cur(void) { }
 static inline void unlock_doms_cur(void) { }
 
-#endif	/* CONFIG_FAIR_GROUP_SCHED */
+#endif	/* CONFIG_GROUP_SCHED */
 
 /* CFS-related fields in a runqueue */
 struct cfs_rq {
@@ -363,7 +370,7 @@ struct cfs_rq {
 struct rt_rq {
 	struct rt_prio_array active;
 	unsigned long rt_nr_running;
-#if defined CONFIG_SMP || defined CONFIG_FAIR_GROUP_SCHED
+#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
 	int highest_prio; /* highest queued rt task prio */
 #endif
 #ifdef CONFIG_SMP
@@ -373,7 +380,9 @@ struct rt_rq {
 	int rt_throttled;
 	u64 rt_time;
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_RT_GROUP_SCHED
+	unsigned long rt_nr_boosted;
+
 	struct rq *rq;
 	struct list_head leaf_rt_rq_list;
 	struct task_group *tg;
@@ -447,6 +456,8 @@ struct rq {
 #ifdef CONFIG_FAIR_GROUP_SCHED
 	/* list of leaf cfs_rq on this cpu: */
 	struct list_head leaf_cfs_rq_list;
+#endif
+#ifdef CONFIG_RT_GROUP_SCHED
 	struct list_head leaf_rt_rq_list;
 #endif
 
@@ -652,19 +663,21 @@ const_debug unsigned int sysctl_sched_features =
 const_debug unsigned int sysctl_sched_nr_migrate = 32;
 
 /*
- * period over which we measure -rt task cpu usage in ms.
+ * period over which we measure -rt task cpu usage in us.
  * default: 1s
  */
-const_debug unsigned int sysctl_sched_rt_period = 1000;
+unsigned int sysctl_sched_rt_period = 1000000;
 
-#define SCHED_RT_FRAC_SHIFT	16
-#define SCHED_RT_FRAC		(1UL << SCHED_RT_FRAC_SHIFT)
+/*
+ * part of the period that we allow rt tasks to run in us.
+ * default: 0.95s
+ */
+int sysctl_sched_rt_runtime = 950000;
 
 /*
- * ratio of time -rt tasks may consume.
- * default: 95%
+ * single value that denotes runtime == period, ie unlimited time.
  */
-const_debug unsigned int sysctl_sched_rt_ratio = 62259;
+#define RUNTIME_INF	((u64)~0ULL)
 
 /*
  * For kernel-internal use: high-speed (but slightly incorrect) per-cpu
@@ -4571,6 +4584,15 @@ recheck:
 			return -EPERM;
 	}
 
+#ifdef CONFIG_RT_GROUP_SCHED
+	/*
+	 * Do not allow realtime tasks into groups that have no runtime
+	 * assigned.
+	 */
+	if (rt_policy(policy) && task_group(p)->rt_runtime == 0)
+		return -EPERM;
+#endif
+
 	retval = security_task_setscheduler(p, policy, param);
 	if (retval)
 		return retval;
@@ -7112,7 +7134,7 @@ static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
 	/* delimiter for bitsearch: */
 	__set_bit(MAX_RT_PRIO, array->bitmap);
 
-#if defined CONFIG_SMP || defined CONFIG_FAIR_GROUP_SCHED
+#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
 	rt_rq->highest_prio = MAX_RT_PRIO;
 #endif
 #ifdef CONFIG_SMP
@@ -7123,7 +7145,8 @@ static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
 	rt_rq->rt_time = 0;
 	rt_rq->rt_throttled = 0;
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_RT_GROUP_SCHED
+	rt_rq->rt_nr_boosted = 0;
 	rt_rq->rq = rq;
 #endif
 }
@@ -7146,7 +7169,9 @@ static void init_tg_cfs_entry(struct rq *rq, struct task_group *tg,
 	se->load.inv_weight = div64_64(1ULL<<32, se->load.weight);
 	se->parent = NULL;
 }
+#endif
 
+#ifdef CONFIG_RT_GROUP_SCHED
 static void init_tg_rt_entry(struct rq *rq, struct task_group *tg,
 		struct rt_rq *rt_rq, struct sched_rt_entity *rt_se,
 		int cpu, int add)
@@ -7175,7 +7200,7 @@ void __init sched_init(void)
 	init_defrootdomain();
 #endif
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_GROUP_SCHED
 	list_add(&init_task_group.list, &task_groups);
 #endif
 
@@ -7196,7 +7221,10 @@ void __init sched_init(void)
 				&per_cpu(init_cfs_rq, i),
 				&per_cpu(init_sched_entity, i), i, 1);
 
-		init_task_group.rt_ratio = sysctl_sched_rt_ratio; /* XXX */
+#endif
+#ifdef CONFIG_RT_GROUP_SCHED
+		init_task_group.rt_runtime =
+			sysctl_sched_rt_runtime * NSEC_PER_USEC;
 		INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
 		init_tg_rt_entry(rq, &init_task_group,
 				&per_cpu(init_rt_rq, i),
@@ -7303,7 +7331,7 @@ void normalize_rt_tasks(void)
 	unsigned long flags;
 	struct rq *rq;
 
-	read_lock_irq(&tasklist_lock);
+	read_lock_irqsave(&tasklist_lock, flags);
 	do_each_thread(g, p) {
 		/*
 		 * Only normalize user tasks:
@@ -7329,16 +7357,16 @@ void normalize_rt_tasks(void)
 			continue;
 		}
 
-		spin_lock_irqsave(&p->pi_lock, flags);
+		spin_lock(&p->pi_lock);
 		rq = __task_rq_lock(p);
 
 		normalize_task(rq, p);
 
 		__task_rq_unlock(rq);
-		spin_unlock_irqrestore(&p->pi_lock, flags);
+		spin_unlock(&p->pi_lock);
 	} while_each_thread(g, p);
 
-	read_unlock_irq(&tasklist_lock);
+	read_unlock_irqrestore(&tasklist_lock, flags);
 }
 
 #endif /* CONFIG_MAGIC_SYSRQ */
@@ -7387,9 +7415,9 @@ void set_curr_task(int cpu, struct task_struct *p)
 
 #endif
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_GROUP_SCHED
 
-#ifdef CONFIG_SMP
+#if defined CONFIG_FAIR_GROUP_SCHED && defined CONFIG_SMP
 /*
  * distribute shares of all task groups among their schedulable entities,
  * to reflect load distribution across cpus.
@@ -7540,7 +7568,8 @@ static int load_balance_monitor(void *unused)
 }
 #endif	/* CONFIG_SMP */
 
-static void free_sched_group(struct task_group *tg)
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void free_fair_sched_group(struct task_group *tg)
 {
 	int i;
 
@@ -7549,49 +7578,27 @@ static void free_sched_group(struct task_group *tg)
 			kfree(tg->cfs_rq[i]);
 		if (tg->se)
 			kfree(tg->se[i]);
-		if (tg->rt_rq)
-			kfree(tg->rt_rq[i]);
-		if (tg->rt_se)
-			kfree(tg->rt_se[i]);
 	}
 
 	kfree(tg->cfs_rq);
 	kfree(tg->se);
-	kfree(tg->rt_rq);
-	kfree(tg->rt_se);
-	kfree(tg);
 }
 
-/* allocate runqueue etc for a new task group */
-struct task_group *sched_create_group(void)
+static int alloc_fair_sched_group(struct task_group *tg)
 {
-	struct task_group *tg;
 	struct cfs_rq *cfs_rq;
 	struct sched_entity *se;
-	struct rt_rq *rt_rq;
-	struct sched_rt_entity *rt_se;
 	struct rq *rq;
 	int i;
 
-	tg = kzalloc(sizeof(*tg), GFP_KERNEL);
-	if (!tg)
-		return ERR_PTR(-ENOMEM);
-
 	tg->cfs_rq = kzalloc(sizeof(cfs_rq) * NR_CPUS, GFP_KERNEL);
 	if (!tg->cfs_rq)
 		goto err;
 	tg->se = kzalloc(sizeof(se) * NR_CPUS, GFP_KERNEL);
 	if (!tg->se)
 		goto err;
-	tg->rt_rq = kzalloc(sizeof(rt_rq) * NR_CPUS, GFP_KERNEL);
-	if (!tg->rt_rq)
-		goto err;
-	tg->rt_se = kzalloc(sizeof(rt_se) * NR_CPUS, GFP_KERNEL);
-	if (!tg->rt_se)
-		goto err;
 
 	tg->shares = NICE_0_LOAD;
-	tg->rt_ratio = 0; /* XXX */
 
 	for_each_possible_cpu(i) {
 		rq = cpu_rq(i);
@@ -7606,6 +7613,79 @@ struct task_group *sched_create_group(void)
 		if (!se)
 			goto err;
 
+		init_tg_cfs_entry(rq, tg, cfs_rq, se, i, 0);
+	}
+
+	return 1;
+
+ err:
+	return 0;
+}
+
+static inline void register_fair_sched_group(struct task_group *tg, int cpu)
+{
+	list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list,
+			&cpu_rq(cpu)->leaf_cfs_rq_list);
+}
+
+static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
+{
+	list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list);
+}
+#else
+static inline void free_fair_sched_group(struct task_group *tg)
+{
+}
+
+static inline int alloc_fair_sched_group(struct task_group *tg)
+{
+	return 1;
+}
+
+static inline void register_fair_sched_group(struct task_group *tg, int cpu)
+{
+}
+
+static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
+{
+}
+#endif
+
+#ifdef CONFIG_RT_GROUP_SCHED
+static void free_rt_sched_group(struct task_group *tg)
+{
+	int i;
+
+	for_each_possible_cpu(i) {
+		if (tg->rt_rq)
+			kfree(tg->rt_rq[i]);
+		if (tg->rt_se)
+			kfree(tg->rt_se[i]);
+	}
+
+	kfree(tg->rt_rq);
+	kfree(tg->rt_se);
+}
+
+static int alloc_rt_sched_group(struct task_group *tg)
+{
+	struct rt_rq *rt_rq;
+	struct sched_rt_entity *rt_se;
+	struct rq *rq;
+	int i;
+
+	tg->rt_rq = kzalloc(sizeof(rt_rq) * NR_CPUS, GFP_KERNEL);
+	if (!tg->rt_rq)
+		goto err;
+	tg->rt_se = kzalloc(sizeof(rt_se) * NR_CPUS, GFP_KERNEL);
+	if (!tg->rt_se)
+		goto err;
+
+	tg->rt_runtime = 0;
+
+	for_each_possible_cpu(i) {
+		rq = cpu_rq(i);
+
 		rt_rq = kmalloc_node(sizeof(struct rt_rq),
 				GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
 		if (!rt_rq)
@@ -7616,20 +7696,75 @@ struct task_group *sched_create_group(void)
 		if (!rt_se)
 			goto err;
 
-		init_tg_cfs_entry(rq, tg, cfs_rq, se, i, 0);
 		init_tg_rt_entry(rq, tg, rt_rq, rt_se, i, 0);
 	}
 
-	lock_task_group_list();
+	return 1;
+
+ err:
+	return 0;
+}
+
+static inline void register_rt_sched_group(struct task_group *tg, int cpu)
+{
+	list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list,
+			&cpu_rq(cpu)->leaf_rt_rq_list);
+}
+
+static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
+{
+	list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list);
+}
+#else
+static inline void free_rt_sched_group(struct task_group *tg)
+{
+}
+
+static inline int alloc_rt_sched_group(struct task_group *tg)
+{
+	return 1;
+}
+
+static inline void register_rt_sched_group(struct task_group *tg, int cpu)
+{
+}
+
+static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
+{
+}
+#endif
+
+static void free_sched_group(struct task_group *tg)
+{
+	free_fair_sched_group(tg);
+	free_rt_sched_group(tg);
+	kfree(tg);
+}
+
+/* allocate runqueue etc for a new task group */
+struct task_group *sched_create_group(void)
+{
+	struct task_group *tg;
+	unsigned long flags;
+	int i;
+
+	tg = kzalloc(sizeof(*tg), GFP_KERNEL);
+	if (!tg)
+		return ERR_PTR(-ENOMEM);
+
+	if (!alloc_fair_sched_group(tg))
+		goto err;
+
+	if (!alloc_rt_sched_group(tg))
+		goto err;
+
+	spin_lock_irqsave(&task_group_lock, flags);
 	for_each_possible_cpu(i) {
-		rq = cpu_rq(i);
-		cfs_rq = tg->cfs_rq[i];
-		list_add_rcu(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
-		rt_rq = tg->rt_rq[i];
-		list_add_rcu(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list);
+		register_fair_sched_group(tg, i);
+		register_rt_sched_group(tg, i);
 	}
 	list_add_rcu(&tg->list, &task_groups);
-	unlock_task_group_list();
+	spin_unlock_irqrestore(&task_group_lock, flags);
 
 	return tg;
 
@@ -7648,21 +7783,16 @@ static void free_sched_group_rcu(struct rcu_head *rhp)
 /* Destroy runqueue etc associated with a task group */
 void sched_destroy_group(struct task_group *tg)
 {
-	struct cfs_rq *cfs_rq = NULL;
-	struct rt_rq *rt_rq = NULL;
+	unsigned long flags;
 	int i;
 
-	lock_task_group_list();
+	spin_lock_irqsave(&task_group_lock, flags);
 	for_each_possible_cpu(i) {
-		cfs_rq = tg->cfs_rq[i];
-		list_del_rcu(&cfs_rq->leaf_cfs_rq_list);
-		rt_rq = tg->rt_rq[i];
-		list_del_rcu(&rt_rq->leaf_rt_rq_list);
+		unregister_fair_sched_group(tg, i);
+		unregister_rt_sched_group(tg, i);
 	}
 	list_del_rcu(&tg->list);
-	unlock_task_group_list();
-
-	BUG_ON(!cfs_rq);
+	spin_unlock_irqrestore(&task_group_lock, flags);
 
 	/* wait for possible concurrent references to cfs_rqs complete */
 	call_rcu(&tg->rcu, free_sched_group_rcu);
@@ -7703,6 +7833,7 @@ void sched_move_task(struct task_struct *tsk)
 	task_rq_unlock(rq, &flags);
 }
 
+#ifdef CONFIG_FAIR_GROUP_SCHED
 /* rq->lock to be locked by caller */
 static void set_se_shares(struct sched_entity *se, unsigned long shares)
 {
@@ -7728,13 +7859,14 @@ static void set_se_shares(struct sched_entity *se, unsigned long shares)
 	}
 }
 
+static DEFINE_MUTEX(shares_mutex);
+
 int sched_group_set_shares(struct task_group *tg, unsigned long shares)
 {
 	int i;
-	struct cfs_rq *cfs_rq;
-	struct rq *rq;
+	unsigned long flags;
 
-	lock_task_group_list();
+	mutex_lock(&shares_mutex);
 	if (tg->shares == shares)
 		goto done;
 
@@ -7746,10 +7878,10 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares)
 	 * load_balance_fair) from referring to this group first,
 	 * by taking it off the rq->leaf_cfs_rq_list on each cpu.
 	 */
-	for_each_possible_cpu(i) {
-		cfs_rq = tg->cfs_rq[i];
-		list_del_rcu(&cfs_rq->leaf_cfs_rq_list);
-	}
+	spin_lock_irqsave(&task_group_lock, flags);
+	for_each_possible_cpu(i)
+		unregister_fair_sched_group(tg, i);
+	spin_unlock_irqrestore(&task_group_lock, flags);
 
 	/* wait for any ongoing reference to this group to finish */
 	synchronize_sched();
@@ -7769,13 +7901,12 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares)
 	 * Enable load balance activity on this group, by inserting it back on
 	 * each cpu's rq->leaf_cfs_rq_list.
 	 */
-	for_each_possible_cpu(i) {
-		rq = cpu_rq(i);
-		cfs_rq = tg->cfs_rq[i];
-		list_add_rcu(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
-	}
+	spin_lock_irqsave(&task_group_lock, flags);
+	for_each_possible_cpu(i)
+		register_fair_sched_group(tg, i);
+	spin_unlock_irqrestore(&task_group_lock, flags);
 done:
-	unlock_task_group_list();
+	mutex_unlock(&shares_mutex);
 	return 0;
 }
 
@@ -7783,35 +7914,84 @@ unsigned long sched_group_shares(struct task_group *tg)
 {
 	return tg->shares;
 }
+#endif
 
+#ifdef CONFIG_RT_GROUP_SCHED
 /*
- * Ensure the total rt_ratio <= sysctl_sched_rt_ratio
+ * Ensure that the real time constraints are schedulable.
  */
-int sched_group_set_rt_ratio(struct task_group *tg, unsigned long rt_ratio)
+static DEFINE_MUTEX(rt_constraints_mutex);
+
+static unsigned long to_ratio(u64 period, u64 runtime)
+{
+	if (runtime == RUNTIME_INF)
+		return 1ULL << 16;
+
+	runtime *= (1ULL << 16);
+	div64_64(runtime, period);
+	return runtime;
+}
+
+static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
 {
 	struct task_group *tgi;
 	unsigned long total = 0;
+	unsigned long global_ratio =
+		to_ratio(sysctl_sched_rt_period,
+			 sysctl_sched_rt_runtime < 0 ?
+				RUNTIME_INF : sysctl_sched_rt_runtime);
 
 	rcu_read_lock();
-	list_for_each_entry_rcu(tgi, &task_groups, list)
-		total += tgi->rt_ratio;
-	rcu_read_unlock();
+	list_for_each_entry_rcu(tgi, &task_groups, list) {
+		if (tgi == tg)
+			continue;
 
-	if (total + rt_ratio - tg->rt_ratio > sysctl_sched_rt_ratio)
-		return -EINVAL;
+		total += to_ratio(period, tgi->rt_runtime);
+	}
+	rcu_read_unlock();
 
-	tg->rt_ratio = rt_ratio;
-	return 0;
+	return total + to_ratio(period, runtime) < global_ratio;
 }
 
-unsigned long sched_group_rt_ratio(struct task_group *tg)
+int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
 {
-	return tg->rt_ratio;
+	u64 rt_runtime, rt_period;
+	int err = 0;
+
+	rt_period = sysctl_sched_rt_period * NSEC_PER_USEC;
+	rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
+	if (rt_runtime_us == -1)
+		rt_runtime = rt_period;
+
+	mutex_lock(&rt_constraints_mutex);
+	if (!__rt_schedulable(tg, rt_period, rt_runtime)) {
+		err = -EINVAL;
+		goto unlock;
+	}
+	if (rt_runtime_us == -1)
+		rt_runtime = RUNTIME_INF;
+	tg->rt_runtime = rt_runtime;
+ unlock:
+	mutex_unlock(&rt_constraints_mutex);
+
+	return err;
 }
 
-#endif	/* CONFIG_FAIR_GROUP_SCHED */
+long sched_group_rt_runtime(struct task_group *tg)
+{
+	u64 rt_runtime_us;
+
+	if (tg->rt_runtime == RUNTIME_INF)
+		return -1;
+
+	rt_runtime_us = tg->rt_runtime;
+	do_div(rt_runtime_us, NSEC_PER_USEC);
+	return rt_runtime_us;
+}
+#endif
+#endif	/* CONFIG_GROUP_SCHED */
 
-#ifdef CONFIG_FAIR_CGROUP_SCHED
+#ifdef CONFIG_CGROUP_SCHED
 
 /* return corresponding task_group object of a cgroup */
 static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
@@ -7857,9 +8037,15 @@ static int
 cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
 		      struct task_struct *tsk)
 {
+#ifdef CONFIG_RT_GROUP_SCHED
+	/* Don't accept realtime tasks when there is no way for them to run */
+	if (rt_task(tsk) && cgroup_tg(cgrp)->rt_runtime == 0)
+		return -EINVAL;
+#else
 	/* We don't support RT-tasks being in separate groups */
 	if (tsk->sched_class != &fair_sched_class)
 		return -EINVAL;
+#endif
 
 	return 0;
 }
@@ -7871,6 +8057,7 @@ cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
 	sched_move_task(tsk);
 }
 
+#ifdef CONFIG_FAIR_GROUP_SCHED
 static int cpu_shares_write_uint(struct cgroup *cgrp, struct cftype *cftype,
 				u64 shareval)
 {
@@ -7883,31 +8070,70 @@ static u64 cpu_shares_read_uint(struct cgroup *cgrp, struct cftype *cft)
 
 	return (u64) tg->shares;
 }
+#endif
 
-static int cpu_rt_ratio_write_uint(struct cgroup *cgrp, struct cftype *cftype,
-		u64 rt_ratio_val)
+#ifdef CONFIG_RT_GROUP_SCHED
+static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
+				struct file *file,
+				const char __user *userbuf,
+				size_t nbytes, loff_t *unused_ppos)
 {
-	return sched_group_set_rt_ratio(cgroup_tg(cgrp), rt_ratio_val);
+	char buffer[64];
+	int retval = 0;
+	s64 val;
+	char *end;
+
+	if (!nbytes)
+		return -EINVAL;
+	if (nbytes >= sizeof(buffer))
+		return -E2BIG;
+	if (copy_from_user(buffer, userbuf, nbytes))
+		return -EFAULT;
+
+	buffer[nbytes] = 0;     /* nul-terminate */
+
+	/* strip newline if necessary */
+	if (nbytes && (buffer[nbytes-1] == '\n'))
+		buffer[nbytes-1] = 0;
+	val = simple_strtoll(buffer, &end, 0);
+	if (*end)
+		return -EINVAL;
+
+	/* Pass to subsystem */
+	retval = sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
+	if (!retval)
+		retval = nbytes;
+	return retval;
 }
 
-static u64 cpu_rt_ratio_read_uint(struct cgroup *cgrp, struct cftype *cft)
+static ssize_t cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft,
+				   struct file *file,
+				   char __user *buf, size_t nbytes,
+				   loff_t *ppos)
 {
-	struct task_group *tg = cgroup_tg(cgrp);
+	char tmp[64];
+	long val = sched_group_rt_runtime(cgroup_tg(cgrp));
+	int len = sprintf(tmp, "%ld\n", val);
 
-	return (u64) tg->rt_ratio;
+	return simple_read_from_buffer(buf, nbytes, ppos, tmp, len);
 }
+#endif
 
 static struct cftype cpu_files[] = {
+#ifdef CONFIG_FAIR_GROUP_SCHED
 	{
 		.name = "shares",
 		.read_uint = cpu_shares_read_uint,
 		.write_uint = cpu_shares_write_uint,
 	},
+#endif
+#ifdef CONFIG_RT_GROUP_SCHED
 	{
-		.name = "rt_ratio",
-		.read_uint = cpu_rt_ratio_read_uint,
-		.write_uint = cpu_rt_ratio_write_uint,
+		.name = "rt_runtime_us",
+		.read = cpu_rt_runtime_read,
+		.write = cpu_rt_runtime_write,
 	},
+#endif
 };
 
 static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
@@ -7926,7 +8152,7 @@ struct cgroup_subsys cpu_cgroup_subsys = {
 	.early_init	= 1,
 };
 
-#endif	/* CONFIG_FAIR_CGROUP_SCHED */
+#endif	/* CONFIG_CGROUP_SCHED */
 
 #ifdef CONFIG_CGROUP_CPUACCT