nfsd: track last inode only in use_wgather case
[safe/jmp/linux-2.6] / kernel / sched_rt.c
index 8bc1761..9bf0d2a 100644 (file)
@@ -3,6 +3,40 @@
  * policies)
  */
 
+static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
+{
+       return container_of(rt_se, struct task_struct, rt);
+}
+
+#ifdef CONFIG_RT_GROUP_SCHED
+
+static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
+{
+       return rt_rq->rq;
+}
+
+static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
+{
+       return rt_se->rt_rq;
+}
+
+#else /* CONFIG_RT_GROUP_SCHED */
+
+static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
+{
+       return container_of(rt_rq, struct rq, rt);
+}
+
+static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
+{
+       struct task_struct *p = rt_task_of(rt_se);
+       struct rq *rq = task_rq(p);
+
+       return &rq->rt;
+}
+
+#endif /* CONFIG_RT_GROUP_SCHED */
+
 #ifdef CONFIG_SMP
 
 static inline int rt_overloaded(struct rq *rq)
@@ -12,7 +46,10 @@ static inline int rt_overloaded(struct rq *rq)
 
 static inline void rt_set_overload(struct rq *rq)
 {
-       cpu_set(rq->cpu, rq->rd->rto_mask);
+       if (!rq->online)
+               return;
+
+       cpumask_set_cpu(rq->cpu, rq->rd->rto_mask);
        /*
         * Make sure the mask is visible before we set
         * the overload count. That is checked to determine
@@ -26,30 +63,77 @@ static inline void rt_set_overload(struct rq *rq)
 
 static inline void rt_clear_overload(struct rq *rq)
 {
+       if (!rq->online)
+               return;
+
        /* the order here really doesn't matter */
        atomic_dec(&rq->rd->rto_count);
-       cpu_clear(rq->cpu, rq->rd->rto_mask);
+       cpumask_clear_cpu(rq->cpu, rq->rd->rto_mask);
 }
 
-static void update_rt_migration(struct rq *rq)
+static void update_rt_migration(struct rt_rq *rt_rq)
 {
-       if (rq->rt.rt_nr_migratory && (rq->rt.rt_nr_running > 1)) {
-               if (!rq->rt.overloaded) {
-                       rt_set_overload(rq);
-                       rq->rt.overloaded = 1;
+       if (rt_rq->rt_nr_migratory && (rt_rq->rt_nr_running > 1)) {
+               if (!rt_rq->overloaded) {
+                       rt_set_overload(rq_of_rt_rq(rt_rq));
+                       rt_rq->overloaded = 1;
                }
-       } else if (rq->rt.overloaded) {
-               rt_clear_overload(rq);
-               rq->rt.overloaded = 0;
+       } else if (rt_rq->overloaded) {
+               rt_clear_overload(rq_of_rt_rq(rt_rq));
+               rt_rq->overloaded = 0;
        }
 }
-#endif /* CONFIG_SMP */
 
-static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
+static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+       if (rt_se->nr_cpus_allowed > 1)
+               rt_rq->rt_nr_migratory++;
+
+       update_rt_migration(rt_rq);
+}
+
+static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+       if (rt_se->nr_cpus_allowed > 1)
+               rt_rq->rt_nr_migratory--;
+
+       update_rt_migration(rt_rq);
+}
+
+static void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
+{
+       plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
+       plist_node_init(&p->pushable_tasks, p->prio);
+       plist_add(&p->pushable_tasks, &rq->rt.pushable_tasks);
+}
+
+static void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
+{
+       plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
+}
+
+#else
+
+static inline void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline
+void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+}
+
+static inline
+void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
 {
-       return container_of(rt_se, struct task_struct, rt);
 }
 
+#endif /* CONFIG_SMP */
+
 static inline int on_rt_rq(struct sched_rt_entity *rt_se)
 {
        return !list_empty(&rt_se->run_list);
@@ -62,21 +146,16 @@ static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
        if (!rt_rq->tg)
                return RUNTIME_INF;
 
-       return rt_rq->tg->rt_bandwidth.rt_runtime;
+       return rt_rq->rt_runtime;
 }
 
-#define for_each_leaf_rt_rq(rt_rq, rq) \
-       list_for_each_entry(rt_rq, &rq->leaf_rt_rq_list, leaf_rt_rq_list)
-
-static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
+static inline u64 sched_rt_period(struct rt_rq *rt_rq)
 {
-       return rt_rq->rq;
+       return ktime_to_ns(rt_rq->tg->rt_bandwidth.rt_period);
 }
 
-static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
-{
-       return rt_se->rt_rq;
-}
+#define for_each_leaf_rt_rq(rt_rq, rq) \
+       list_for_each_entry_rcu(rt_rq, &rq->leaf_rt_rq_list, leaf_rt_rq_list)
 
 #define for_each_sched_rt_entity(rt_se) \
        for (; rt_se; rt_se = rt_se->parent)
@@ -91,13 +170,13 @@ static void dequeue_rt_entity(struct sched_rt_entity *rt_se);
 
 static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
 {
+       struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
        struct sched_rt_entity *rt_se = rt_rq->rt_se;
 
-       if (rt_se && !on_rt_rq(rt_se) && rt_rq->rt_nr_running) {
-               struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
-
-               enqueue_rt_entity(rt_se);
-               if (rt_rq->highest_prio < curr->prio)
+       if (rt_rq->rt_nr_running) {
+               if (rt_se && !on_rt_rq(rt_se))
+                       enqueue_rt_entity(rt_se);
+               if (rt_rq->highest_prio.curr < curr->prio)
                        resched_task(curr);
        }
 }
@@ -128,14 +207,14 @@ static int rt_se_boosted(struct sched_rt_entity *rt_se)
 }
 
 #ifdef CONFIG_SMP
-static inline cpumask_t sched_rt_period_mask(void)
+static inline const struct cpumask *sched_rt_period_mask(void)
 {
        return cpu_rq(smp_processor_id())->rd->span;
 }
 #else
-static inline cpumask_t sched_rt_period_mask(void)
+static inline const struct cpumask *sched_rt_period_mask(void)
 {
-       return cpu_online_map;
+       return cpu_online_mask;
 }
 #endif
 
@@ -145,29 +224,26 @@ struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
        return container_of(rt_b, struct task_group, rt_bandwidth)->rt_rq[cpu];
 }
 
-#else
-
-static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
+static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
 {
-       return def_rt_bandwidth.rt_runtime;
+       return &rt_rq->tg->rt_bandwidth;
 }
 
-#define for_each_leaf_rt_rq(rt_rq, rq) \
-       for (rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
+#else /* !CONFIG_RT_GROUP_SCHED */
 
-static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
+static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
 {
-       return container_of(rt_rq, struct rq, rt);
+       return rt_rq->rt_runtime;
 }
 
-static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
+static inline u64 sched_rt_period(struct rt_rq *rt_rq)
 {
-       struct task_struct *p = rt_task_of(rt_se);
-       struct rq *rq = task_rq(p);
-
-       return &rq->rt;
+       return ktime_to_ns(def_rt_bandwidth.rt_period);
 }
 
+#define for_each_leaf_rt_rq(rt_rq, rq) \
+       for (rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
+
 #define for_each_sched_rt_entity(rt_se) \
        for (; rt_se; rt_se = NULL)
 
@@ -178,6 +254,8 @@ static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
 
 static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
 {
+       if (rt_rq->rt_nr_running)
+               resched_task(rq_of_rt_rq(rt_rq)->curr);
 }
 
 static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
@@ -189,9 +267,9 @@ static inline int rt_rq_throttled(struct rt_rq *rt_rq)
        return rt_rq->rt_throttled;
 }
 
-static inline cpumask_t sched_rt_period_mask(void)
+static inline const struct cpumask *sched_rt_period_mask(void)
 {
-       return cpu_online_map;
+       return cpu_online_mask;
 }
 
 static inline
@@ -200,26 +278,231 @@ struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
        return &cpu_rq(cpu)->rt;
 }
 
-#endif
+static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
+{
+       return &def_rt_bandwidth;
+}
+
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+#ifdef CONFIG_SMP
+/*
+ * We ran out of runtime, see if we can borrow some from our neighbours.
+ */
+static int do_balance_runtime(struct rt_rq *rt_rq)
+{
+       struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+       struct root_domain *rd = cpu_rq(smp_processor_id())->rd;
+       int i, weight, more = 0;
+       u64 rt_period;
+
+       weight = cpumask_weight(rd->span);
+
+       spin_lock(&rt_b->rt_runtime_lock);
+       rt_period = ktime_to_ns(rt_b->rt_period);
+       for_each_cpu(i, rd->span) {
+               struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
+               s64 diff;
+
+               if (iter == rt_rq)
+                       continue;
+
+               spin_lock(&iter->rt_runtime_lock);
+               /*
+                * Either all rqs have inf runtime and there's nothing to steal
+                * or __disable_runtime() below sets a specific rq to inf to
+                * indicate its been disabled and disalow stealing.
+                */
+               if (iter->rt_runtime == RUNTIME_INF)
+                       goto next;
+
+               /*
+                * From runqueues with spare time, take 1/n part of their
+                * spare time, but no more than our period.
+                */
+               diff = iter->rt_runtime - iter->rt_time;
+               if (diff > 0) {
+                       diff = div_u64((u64)diff, weight);
+                       if (rt_rq->rt_runtime + diff > rt_period)
+                               diff = rt_period - rt_rq->rt_runtime;
+                       iter->rt_runtime -= diff;
+                       rt_rq->rt_runtime += diff;
+                       more = 1;
+                       if (rt_rq->rt_runtime == rt_period) {
+                               spin_unlock(&iter->rt_runtime_lock);
+                               break;
+                       }
+               }
+next:
+               spin_unlock(&iter->rt_runtime_lock);
+       }
+       spin_unlock(&rt_b->rt_runtime_lock);
+
+       return more;
+}
+
+/*
+ * Ensure this RQ takes back all the runtime it lend to its neighbours.
+ */
+static void __disable_runtime(struct rq *rq)
+{
+       struct root_domain *rd = rq->rd;
+       struct rt_rq *rt_rq;
+
+       if (unlikely(!scheduler_running))
+               return;
+
+       for_each_leaf_rt_rq(rt_rq, rq) {
+               struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+               s64 want;
+               int i;
+
+               spin_lock(&rt_b->rt_runtime_lock);
+               spin_lock(&rt_rq->rt_runtime_lock);
+               /*
+                * Either we're all inf and nobody needs to borrow, or we're
+                * already disabled and thus have nothing to do, or we have
+                * exactly the right amount of runtime to take out.
+                */
+               if (rt_rq->rt_runtime == RUNTIME_INF ||
+                               rt_rq->rt_runtime == rt_b->rt_runtime)
+                       goto balanced;
+               spin_unlock(&rt_rq->rt_runtime_lock);
+
+               /*
+                * Calculate the difference between what we started out with
+                * and what we current have, that's the amount of runtime
+                * we lend and now have to reclaim.
+                */
+               want = rt_b->rt_runtime - rt_rq->rt_runtime;
+
+               /*
+                * Greedy reclaim, take back as much as we can.
+                */
+               for_each_cpu(i, rd->span) {
+                       struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
+                       s64 diff;
+
+                       /*
+                        * Can't reclaim from ourselves or disabled runqueues.
+                        */
+                       if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
+                               continue;
+
+                       spin_lock(&iter->rt_runtime_lock);
+                       if (want > 0) {
+                               diff = min_t(s64, iter->rt_runtime, want);
+                               iter->rt_runtime -= diff;
+                               want -= diff;
+                       } else {
+                               iter->rt_runtime -= want;
+                               want -= want;
+                       }
+                       spin_unlock(&iter->rt_runtime_lock);
+
+                       if (!want)
+                               break;
+               }
+
+               spin_lock(&rt_rq->rt_runtime_lock);
+               /*
+                * We cannot be left wanting - that would mean some runtime
+                * leaked out of the system.
+                */
+               BUG_ON(want);
+balanced:
+               /*
+                * Disable all the borrow logic by pretending we have inf
+                * runtime - in which case borrowing doesn't make sense.
+                */
+               rt_rq->rt_runtime = RUNTIME_INF;
+               spin_unlock(&rt_rq->rt_runtime_lock);
+               spin_unlock(&rt_b->rt_runtime_lock);
+       }
+}
+
+static void disable_runtime(struct rq *rq)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&rq->lock, flags);
+       __disable_runtime(rq);
+       spin_unlock_irqrestore(&rq->lock, flags);
+}
+
+static void __enable_runtime(struct rq *rq)
+{
+       struct rt_rq *rt_rq;
+
+       if (unlikely(!scheduler_running))
+               return;
+
+       /*
+        * Reset each runqueue's bandwidth settings
+        */
+       for_each_leaf_rt_rq(rt_rq, rq) {
+               struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+
+               spin_lock(&rt_b->rt_runtime_lock);
+               spin_lock(&rt_rq->rt_runtime_lock);
+               rt_rq->rt_runtime = rt_b->rt_runtime;
+               rt_rq->rt_time = 0;
+               rt_rq->rt_throttled = 0;
+               spin_unlock(&rt_rq->rt_runtime_lock);
+               spin_unlock(&rt_b->rt_runtime_lock);
+       }
+}
+
+static void enable_runtime(struct rq *rq)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&rq->lock, flags);
+       __enable_runtime(rq);
+       spin_unlock_irqrestore(&rq->lock, flags);
+}
+
+static int balance_runtime(struct rt_rq *rt_rq)
+{
+       int more = 0;
+
+       if (rt_rq->rt_time > rt_rq->rt_runtime) {
+               spin_unlock(&rt_rq->rt_runtime_lock);
+               more = do_balance_runtime(rt_rq);
+               spin_lock(&rt_rq->rt_runtime_lock);
+       }
+
+       return more;
+}
+#else /* !CONFIG_SMP */
+static inline int balance_runtime(struct rt_rq *rt_rq)
+{
+       return 0;
+}
+#endif /* CONFIG_SMP */
 
 static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
 {
        int i, idle = 1;
-       cpumask_t span;
+       const struct cpumask *span;
 
-       if (rt_b->rt_runtime == RUNTIME_INF)
+       if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
                return 1;
 
        span = sched_rt_period_mask();
-       for_each_cpu_mask(i, span) {
+       for_each_cpu(i, span) {
                int enqueue = 0;
                struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i);
                struct rq *rq = rq_of_rt_rq(rt_rq);
 
                spin_lock(&rq->lock);
                if (rt_rq->rt_time) {
-                       u64 runtime = rt_b->rt_runtime;
+                       u64 runtime;
 
+                       spin_lock(&rt_rq->rt_runtime_lock);
+                       if (rt_rq->rt_throttled)
+                               balance_runtime(rt_rq);
+                       runtime = rt_rq->rt_runtime;
                        rt_rq->rt_time -= min(rt_rq->rt_time, overrun*runtime);
                        if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) {
                                rt_rq->rt_throttled = 0;
@@ -227,7 +510,9 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
                        }
                        if (rt_rq->rt_time || rt_rq->rt_nr_running)
                                idle = 0;
-               }
+                       spin_unlock(&rt_rq->rt_runtime_lock);
+               } else if (rt_rq->rt_nr_running)
+                       idle = 0;
 
                if (enqueue)
                        sched_rt_rq_enqueue(rt_rq);
@@ -243,7 +528,7 @@ static inline int rt_se_prio(struct sched_rt_entity *rt_se)
        struct rt_rq *rt_rq = group_rt_rq(rt_se);
 
        if (rt_rq)
-               return rt_rq->highest_prio;
+               return rt_rq->highest_prio.curr;
 #endif
 
        return rt_task_of(rt_se)->prio;
@@ -253,12 +538,17 @@ static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
 {
        u64 runtime = sched_rt_runtime(rt_rq);
 
-       if (runtime == RUNTIME_INF)
-               return 0;
-
        if (rt_rq->rt_throttled)
                return rt_rq_throttled(rt_rq);
 
+       if (sched_rt_runtime(rt_rq) >= sched_rt_period(rt_rq))
+               return 0;
+
+       balance_runtime(rt_rq);
+       runtime = sched_rt_runtime(rt_rq);
+       if (runtime == RUNTIME_INF)
+               return 0;
+
        if (rt_rq->rt_time > runtime) {
                rt_rq->rt_throttled = 1;
                if (rt_rq_throttled(rt_rq)) {
@@ -291,40 +581,183 @@ static void update_curr_rt(struct rq *rq)
        schedstat_set(curr->se.exec_max, max(curr->se.exec_max, delta_exec));
 
        curr->se.sum_exec_runtime += delta_exec;
+       account_group_exec_runtime(curr, delta_exec);
+
        curr->se.exec_start = rq->clock;
        cpuacct_charge(curr, delta_exec);
 
-       rt_rq->rt_time += delta_exec;
-       if (sched_rt_runtime_exceeded(rt_rq))
-               resched_task(curr);
+       if (!rt_bandwidth_enabled())
+               return;
+
+       for_each_sched_rt_entity(rt_se) {
+               rt_rq = rt_rq_of_se(rt_se);
+
+               if (sched_rt_runtime(rt_rq) != RUNTIME_INF) {
+                       spin_lock(&rt_rq->rt_runtime_lock);
+                       rt_rq->rt_time += delta_exec;
+                       if (sched_rt_runtime_exceeded(rt_rq))
+                               resched_task(curr);
+                       spin_unlock(&rt_rq->rt_runtime_lock);
+               }
+       }
 }
 
-static inline
-void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+#if defined CONFIG_SMP
+
+static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu);
+
+static inline int next_prio(struct rq *rq)
 {
-       WARN_ON(!rt_prio(rt_se_prio(rt_se)));
-       rt_rq->rt_nr_running++;
+       struct task_struct *next = pick_next_highest_task_rt(rq, rq->cpu);
+
+       if (next && rt_prio(next->prio))
+               return next->prio;
+       else
+               return MAX_RT_PRIO;
+}
+
+static void
+inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
+{
+       struct rq *rq = rq_of_rt_rq(rt_rq);
+
+       if (prio < prev_prio) {
+
+               /*
+                * If the new task is higher in priority than anything on the
+                * run-queue, we know that the previous high becomes our
+                * next-highest.
+                */
+               rt_rq->highest_prio.next = prev_prio;
+
+               if (rq->online)
+                       cpupri_set(&rq->rd->cpupri, rq->cpu, prio);
+
+       } else if (prio == rt_rq->highest_prio.curr)
+               /*
+                * If the next task is equal in priority to the highest on
+                * the run-queue, then we implicitly know that the next highest
+                * task cannot be any lower than current
+                */
+               rt_rq->highest_prio.next = prio;
+       else if (prio < rt_rq->highest_prio.next)
+               /*
+                * Otherwise, we need to recompute next-highest
+                */
+               rt_rq->highest_prio.next = next_prio(rq);
+}
+
+static void
+dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
+{
+       struct rq *rq = rq_of_rt_rq(rt_rq);
+
+       if (rt_rq->rt_nr_running && (prio <= rt_rq->highest_prio.next))
+               rt_rq->highest_prio.next = next_prio(rq);
+
+       if (rq->online && rt_rq->highest_prio.curr != prev_prio)
+               cpupri_set(&rq->rd->cpupri, rq->cpu, rt_rq->highest_prio.curr);
+}
+
+#else /* CONFIG_SMP */
+
+static inline
+void inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
+static inline
+void dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
+
+#endif /* CONFIG_SMP */
+
 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
-       if (rt_se_prio(rt_se) < rt_rq->highest_prio)
-               rt_rq->highest_prio = rt_se_prio(rt_se);
-#endif
-#ifdef CONFIG_SMP
-       if (rt_se->nr_cpus_allowed > 1) {
-               struct rq *rq = rq_of_rt_rq(rt_rq);
-               rq->rt.rt_nr_migratory++;
-       }
+static void
+inc_rt_prio(struct rt_rq *rt_rq, int prio)
+{
+       int prev_prio = rt_rq->highest_prio.curr;
+
+       if (prio < prev_prio)
+               rt_rq->highest_prio.curr = prio;
+
+       inc_rt_prio_smp(rt_rq, prio, prev_prio);
+}
+
+static void
+dec_rt_prio(struct rt_rq *rt_rq, int prio)
+{
+       int prev_prio = rt_rq->highest_prio.curr;
+
+       if (rt_rq->rt_nr_running) {
+
+               WARN_ON(prio < prev_prio);
+
+               /*
+                * This may have been our highest task, and therefore
+                * we may have some recomputation to do
+                */
+               if (prio == prev_prio) {
+                       struct rt_prio_array *array = &rt_rq->active;
+
+                       rt_rq->highest_prio.curr =
+                               sched_find_first_bit(array->bitmap);
+               }
+
+       } else
+               rt_rq->highest_prio.curr = MAX_RT_PRIO;
+
+       dec_rt_prio_smp(rt_rq, prio, prev_prio);
+}
+
+#else
+
+static inline void inc_rt_prio(struct rt_rq *rt_rq, int prio) {}
+static inline void dec_rt_prio(struct rt_rq *rt_rq, int prio) {}
+
+#endif /* CONFIG_SMP || CONFIG_RT_GROUP_SCHED */
 
-       update_rt_migration(rq_of_rt_rq(rt_rq));
-#endif
 #ifdef CONFIG_RT_GROUP_SCHED
+
+static void
+inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
        if (rt_se_boosted(rt_se))
                rt_rq->rt_nr_boosted++;
 
        if (rt_rq->tg)
                start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
-#else
+}
+
+static void
+dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+       if (rt_se_boosted(rt_se))
+               rt_rq->rt_nr_boosted--;
+
+       WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted);
+}
+
+#else /* CONFIG_RT_GROUP_SCHED */
+
+static void
+inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
        start_rt_bandwidth(&def_rt_bandwidth);
-#endif
+}
+
+static inline
+void dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) {}
+
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+static inline
+void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+       int prio = rt_se_prio(rt_se);
+
+       WARN_ON(!rt_prio(prio));
+       rt_rq->rt_nr_running++;
+
+       inc_rt_prio(rt_rq, prio);
+       inc_rt_migration(rt_se, rt_rq);
+       inc_rt_group(rt_se, rt_rq);
 }
 
 static inline
@@ -333,52 +766,35 @@ void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
        WARN_ON(!rt_prio(rt_se_prio(rt_se)));
        WARN_ON(!rt_rq->rt_nr_running);
        rt_rq->rt_nr_running--;
-#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
-       if (rt_rq->rt_nr_running) {
-               struct rt_prio_array *array;
 
-               WARN_ON(rt_se_prio(rt_se) < rt_rq->highest_prio);
-               if (rt_se_prio(rt_se) == rt_rq->highest_prio) {
-                       /* recalculate */
-                       array = &rt_rq->active;
-                       rt_rq->highest_prio =
-                               sched_find_first_bit(array->bitmap);
-               } /* otherwise leave rq->highest prio alone */
-       } else
-               rt_rq->highest_prio = MAX_RT_PRIO;
-#endif
-#ifdef CONFIG_SMP
-       if (rt_se->nr_cpus_allowed > 1) {
-               struct rq *rq = rq_of_rt_rq(rt_rq);
-               rq->rt.rt_nr_migratory--;
-       }
-
-       update_rt_migration(rq_of_rt_rq(rt_rq));
-#endif /* CONFIG_SMP */
-#ifdef CONFIG_RT_GROUP_SCHED
-       if (rt_se_boosted(rt_se))
-               rt_rq->rt_nr_boosted--;
-
-       WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted);
-#endif
+       dec_rt_prio(rt_rq, rt_se_prio(rt_se));
+       dec_rt_migration(rt_se, rt_rq);
+       dec_rt_group(rt_se, rt_rq);
 }
 
-static void enqueue_rt_entity(struct sched_rt_entity *rt_se)
+static void __enqueue_rt_entity(struct sched_rt_entity *rt_se)
 {
        struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
        struct rt_prio_array *array = &rt_rq->active;
        struct rt_rq *group_rq = group_rt_rq(rt_se);
+       struct list_head *queue = array->queue + rt_se_prio(rt_se);
 
-       if (group_rq && rt_rq_throttled(group_rq))
+       /*
+        * Don't enqueue the group if its throttled, or when empty.
+        * The latter is a consequence of the former when a child group
+        * get throttled and the current group doesn't have any other
+        * active members.
+        */
+       if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running))
                return;
 
-       list_add_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se));
+       list_add_tail(&rt_se->run_list, queue);
        __set_bit(rt_se_prio(rt_se), array->bitmap);
 
        inc_rt_tasks(rt_se, rt_rq);
 }
 
-static void dequeue_rt_entity(struct sched_rt_entity *rt_se)
+static void __dequeue_rt_entity(struct sched_rt_entity *rt_se)
 {
        struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
        struct rt_prio_array *array = &rt_rq->active;
@@ -393,27 +809,39 @@ static void dequeue_rt_entity(struct sched_rt_entity *rt_se)
 /*
  * Because the prio of an upper entry depends on the lower
  * entries, we must remove entries top - down.
- *
- * XXX: O(1/2 h^2) because we can only walk up, not down the chain.
- *      doesn't matter much for now, as h=2 for GROUP_SCHED.
  */
-static void dequeue_rt_stack(struct task_struct *p)
+static void dequeue_rt_stack(struct sched_rt_entity *rt_se)
 {
-       struct sched_rt_entity *rt_se, *top_se;
+       struct sched_rt_entity *back = NULL;
 
-       /*
-        * dequeue all, top - down.
-        */
-       do {
-               rt_se = &p->rt;
-               top_se = NULL;
-               for_each_sched_rt_entity(rt_se) {
-                       if (on_rt_rq(rt_se))
-                               top_se = rt_se;
-               }
-               if (top_se)
-                       dequeue_rt_entity(top_se);
-       } while (top_se);
+       for_each_sched_rt_entity(rt_se) {
+               rt_se->back = back;
+               back = rt_se;
+       }
+
+       for (rt_se = back; rt_se; rt_se = rt_se->back) {
+               if (on_rt_rq(rt_se))
+                       __dequeue_rt_entity(rt_se);
+       }
+}
+
+static void enqueue_rt_entity(struct sched_rt_entity *rt_se)
+{
+       dequeue_rt_stack(rt_se);
+       for_each_sched_rt_entity(rt_se)
+               __enqueue_rt_entity(rt_se);
+}
+
+static void dequeue_rt_entity(struct sched_rt_entity *rt_se)
+{
+       dequeue_rt_stack(rt_se);
+
+       for_each_sched_rt_entity(rt_se) {
+               struct rt_rq *rt_rq = group_rt_rq(rt_se);
+
+               if (rt_rq && rt_rq->rt_nr_running)
+                       __enqueue_rt_entity(rt_se);
+       }
 }
 
 /*
@@ -426,60 +854,58 @@ static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup)
        if (wakeup)
                rt_se->timeout = 0;
 
-       dequeue_rt_stack(p);
+       enqueue_rt_entity(rt_se);
 
-       /*
-        * enqueue everybody, bottom - up.
-        */
-       for_each_sched_rt_entity(rt_se)
-               enqueue_rt_entity(rt_se);
+       if (!task_current(rq, p) && p->rt.nr_cpus_allowed > 1)
+               enqueue_pushable_task(rq, p);
+
+       inc_cpu_load(rq, p->se.load.weight);
 }
 
 static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep)
 {
        struct sched_rt_entity *rt_se = &p->rt;
-       struct rt_rq *rt_rq;
 
        update_curr_rt(rq);
+       dequeue_rt_entity(rt_se);
 
-       dequeue_rt_stack(p);
+       dequeue_pushable_task(rq, p);
 
-       /*
-        * re-enqueue all non-empty rt_rq entities.
-        */
-       for_each_sched_rt_entity(rt_se) {
-               rt_rq = group_rt_rq(rt_se);
-               if (rt_rq && rt_rq->rt_nr_running)
-                       enqueue_rt_entity(rt_se);
-       }
+       dec_cpu_load(rq, p->se.load.weight);
 }
 
 /*
  * Put task to the end of the run list without the overhead of dequeue
  * followed by enqueue.
  */
-static
-void requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
+static void
+requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, int head)
 {
-       struct rt_prio_array *array = &rt_rq->active;
+       if (on_rt_rq(rt_se)) {
+               struct rt_prio_array *array = &rt_rq->active;
+               struct list_head *queue = array->queue + rt_se_prio(rt_se);
 
-       list_move_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se));
+               if (head)
+                       list_move(&rt_se->run_list, queue);
+               else
+                       list_move_tail(&rt_se->run_list, queue);
+       }
 }
 
-static void requeue_task_rt(struct rq *rq, struct task_struct *p)
+static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head)
 {
        struct sched_rt_entity *rt_se = &p->rt;
        struct rt_rq *rt_rq;
 
        for_each_sched_rt_entity(rt_se) {
                rt_rq = rt_rq_of_se(rt_se);
-               requeue_rt_entity(rt_rq, rt_se);
+               requeue_rt_entity(rt_rq, rt_se, head);
        }
 }
 
 static void yield_task_rt(struct rq *rq)
 {
-       requeue_task_rt(rq, rq->curr);
+       requeue_task_rt(rq, rq->curr, 0);
 }
 
 #ifdef CONFIG_SMP
@@ -519,15 +945,56 @@ static int select_task_rq_rt(struct task_struct *p, int sync)
         */
        return task_cpu(p);
 }
+
+static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
+{
+       if (rq->curr->rt.nr_cpus_allowed == 1)
+               return;
+
+       if (p->rt.nr_cpus_allowed != 1
+           && cpupri_find(&rq->rd->cpupri, p, NULL))
+               return;
+
+       if (!cpupri_find(&rq->rd->cpupri, rq->curr, NULL))
+               return;
+
+       /*
+        * There appears to be other cpus that can accept
+        * current and none to run 'p', so lets reschedule
+        * to try and push current away:
+        */
+       requeue_task_rt(rq, p, 1);
+       resched_task(rq->curr);
+}
+
 #endif /* CONFIG_SMP */
 
 /*
  * Preempt the current task with a newly woken task if needed:
  */
-static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p)
+static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int sync)
 {
-       if (p->prio < rq->curr->prio)
+       if (p->prio < rq->curr->prio) {
                resched_task(rq->curr);
+               return;
+       }
+
+#ifdef CONFIG_SMP
+       /*
+        * If:
+        *
+        * - the newly woken task is of equal priority to the current task
+        * - the newly woken task is non-migratable while current is migratable
+        * - current will be preempted on the next reschedule
+        *
+        * we should check to see if current can readily move to a different
+        * cpu.  If so, we will reschedule to allow the push logic to try
+        * to move current somewhere else, making room for our non-migratable
+        * task.
+        */
+       if (p->prio == rq->curr->prio && !need_resched())
+               check_preempt_equal_prio(rq, p);
+#endif
 }
 
 static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
@@ -547,7 +1014,7 @@ static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
        return next;
 }
 
-static struct task_struct *pick_next_task_rt(struct rq *rq)
+static struct task_struct *_pick_next_task_rt(struct rq *rq)
 {
        struct sched_rt_entity *rt_se;
        struct task_struct *p;
@@ -569,6 +1036,18 @@ static struct task_struct *pick_next_task_rt(struct rq *rq)
 
        p = rt_task_of(rt_se);
        p->se.exec_start = rq->clock;
+
+       return p;
+}
+
+static struct task_struct *pick_next_task_rt(struct rq *rq)
+{
+       struct task_struct *p = _pick_next_task_rt(rq);
+
+       /* The running task is never eligible for pushing */
+       if (p)
+               dequeue_pushable_task(rq, p);
+
        return p;
 }
 
@@ -576,6 +1055,13 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
 {
        update_curr_rt(rq);
        p->se.exec_start = 0;
+
+       /*
+        * The previous task needs to be made eligible for pushing
+        * if it is still active
+        */
+       if (p->se.on_rq && p->rt.nr_cpus_allowed > 1)
+               enqueue_pushable_task(rq, p);
 }
 
 #ifdef CONFIG_SMP
@@ -583,13 +1069,12 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
 /* Only try algorithms three times */
 #define RT_MAX_TRIES 3
 
-static int double_lock_balance(struct rq *this_rq, struct rq *busiest);
 static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep);
 
 static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
 {
        if (!task_running(rq, p) &&
-           (cpu < 0 || cpu_isset(cpu, p->cpus_allowed)) &&
+           (cpu < 0 || cpumask_test_cpu(cpu, &p->cpus_allowed)) &&
            (p->rt.nr_cpus_allowed > 1))
                return 1;
        return 0;
@@ -628,85 +1113,19 @@ static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu)
        return next;
 }
 
-static DEFINE_PER_CPU(cpumask_t, local_cpu_mask);
-
-static int find_lowest_cpus(struct task_struct *task, cpumask_t *lowest_mask)
-{
-       int       lowest_prio = -1;
-       int       lowest_cpu  = -1;
-       int       count       = 0;
-       int       cpu;
-
-       cpus_and(*lowest_mask, task_rq(task)->rd->online, task->cpus_allowed);
-
-       /*
-        * Scan each rq for the lowest prio.
-        */
-       for_each_cpu_mask(cpu, *lowest_mask) {
-               struct rq *rq = cpu_rq(cpu);
-
-               /* We look for lowest RT prio or non-rt CPU */
-               if (rq->rt.highest_prio >= MAX_RT_PRIO) {
-                       /*
-                        * if we already found a low RT queue
-                        * and now we found this non-rt queue
-                        * clear the mask and set our bit.
-                        * Otherwise just return the queue as is
-                        * and the count==1 will cause the algorithm
-                        * to use the first bit found.
-                        */
-                       if (lowest_cpu != -1) {
-                               cpus_clear(*lowest_mask);
-                               cpu_set(rq->cpu, *lowest_mask);
-                       }
-                       return 1;
-               }
-
-               /* no locking for now */
-               if ((rq->rt.highest_prio > task->prio)
-                   && (rq->rt.highest_prio >= lowest_prio)) {
-                       if (rq->rt.highest_prio > lowest_prio) {
-                               /* new low - clear old data */
-                               lowest_prio = rq->rt.highest_prio;
-                               lowest_cpu = cpu;
-                               count = 0;
-                       }
-                       count++;
-               } else
-                       cpu_clear(cpu, *lowest_mask);
-       }
+static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask);
 
-       /*
-        * Clear out all the set bits that represent
-        * runqueues that were of higher prio than
-        * the lowest_prio.
-        */
-       if (lowest_cpu > 0) {
-               /*
-                * Perhaps we could add another cpumask op to
-                * zero out bits. Like cpu_zero_bits(cpumask, nrbits);
-                * Then that could be optimized to use memset and such.
-                */
-               for_each_cpu_mask(cpu, *lowest_mask) {
-                       if (cpu >= lowest_cpu)
-                               break;
-                       cpu_clear(cpu, *lowest_mask);
-               }
-       }
-
-       return count;
-}
-
-static inline int pick_optimal_cpu(int this_cpu, cpumask_t *mask)
+static inline int pick_optimal_cpu(int this_cpu,
+                                  const struct cpumask *mask)
 {
        int first;
 
        /* "this_cpu" is cheaper to preempt than a remote processor */
-       if ((this_cpu != -1) && cpu_isset(this_cpu, *mask))
+       if ((this_cpu != -1) && cpumask_test_cpu(this_cpu, mask))
                return this_cpu;
 
-       first = first_cpu(*mask);
-       if (first != NR_CPUS)
+       first = cpumask_first(mask);
+       if (first < nr_cpu_ids)
                return first;
 
        return -1;
@@ -715,20 +1134,23 @@ static inline int pick_optimal_cpu(int this_cpu, cpumask_t *mask)
 static int find_lowest_rq(struct task_struct *task)
 {
        struct sched_domain *sd;
-       cpumask_t *lowest_mask = &__get_cpu_var(local_cpu_mask);
+       struct cpumask *lowest_mask = __get_cpu_var(local_cpu_mask);
        int this_cpu = smp_processor_id();
        int cpu      = task_cpu(task);
-       int count    = find_lowest_cpus(task, lowest_mask);
+       cpumask_var_t domain_mask;
+
+       if (task->rt.nr_cpus_allowed == 1)
+               return -1; /* No other targets possible */
 
-       if (!count)
+       if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask))
                return -1; /* No targets found */
 
        /*
-        * There is no sense in performing an optimal search if only one
-        * target is found.
+        * Only consider CPUs that are usable for migration.
+        * I guess we might want to change cpupri_find() to ignore those
+        * in the first place.
         */
-       if (count == 1)
-               return first_cpu(*lowest_mask);
+       cpumask_and(lowest_mask, lowest_mask, cpu_active_mask);
 
        /*
         * At this point we have built a mask of cpus representing the
@@ -738,7 +1160,7 @@ static int find_lowest_rq(struct task_struct *task)
         * We prioritize the last cpu that the task executed on since
         * it is most likely cache-hot in that location.
         */
-       if (cpu_isset(cpu, *lowest_mask))
+       if (cpumask_test_cpu(cpu, lowest_mask))
                return cpu;
 
        /*
@@ -748,18 +1170,25 @@ static int find_lowest_rq(struct task_struct *task)
        if (this_cpu == cpu)
                this_cpu = -1; /* Skip this_cpu opt if the same */
 
-       for_each_domain(cpu, sd) {
-               if (sd->flags & SD_WAKE_AFFINE) {
-                       cpumask_t domain_mask;
-                       int       best_cpu;
+       if (alloc_cpumask_var(&domain_mask, GFP_ATOMIC)) {
+               for_each_domain(cpu, sd) {
+                       if (sd->flags & SD_WAKE_AFFINE) {
+                               int best_cpu;
+
+                               cpumask_and(domain_mask,
+                                           sched_domain_span(sd),
+                                           lowest_mask);
 
-                       cpus_and(domain_mask, sd->span, *lowest_mask);
+                               best_cpu = pick_optimal_cpu(this_cpu,
+                                                           domain_mask);
 
-                       best_cpu = pick_optimal_cpu(this_cpu,
-                                                   &domain_mask);
-                       if (best_cpu != -1)
-                               return best_cpu;
+                               if (best_cpu != -1) {
+                                       free_cpumask_var(domain_mask);
+                                       return best_cpu;
+                               }
+                       }
                }
+               free_cpumask_var(domain_mask);
        }
 
        /*
@@ -794,8 +1223,8 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
                         * Also make sure that it wasn't scheduled on its rq.
                         */
                        if (unlikely(task_rq(task) != rq ||
-                                    !cpu_isset(lowest_rq->cpu,
-                                               task->cpus_allowed) ||
+                                    !cpumask_test_cpu(lowest_rq->cpu,
+                                                      &task->cpus_allowed) ||
                                     task_running(rq, task) ||
                                     !task->se.on_rq)) {
 
@@ -806,17 +1235,42 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
                }
 
                /* If this rq is still suitable use it. */
-               if (lowest_rq->rt.highest_prio > task->prio)
+               if (lowest_rq->rt.highest_prio.curr > task->prio)
                        break;
 
                /* try again */
-               spin_unlock(&lowest_rq->lock);
+               double_unlock_balance(rq, lowest_rq);
                lowest_rq = NULL;
        }
 
        return lowest_rq;
 }
 
+static inline int has_pushable_tasks(struct rq *rq)
+{
+       return !plist_head_empty(&rq->rt.pushable_tasks);
+}
+
+static struct task_struct *pick_next_pushable_task(struct rq *rq)
+{
+       struct task_struct *p;
+
+       if (!has_pushable_tasks(rq))
+               return NULL;
+
+       p = plist_first_entry(&rq->rt.pushable_tasks,
+                             struct task_struct, pushable_tasks);
+
+       BUG_ON(rq->cpu != task_cpu(p));
+       BUG_ON(task_current(rq, p));
+       BUG_ON(p->rt.nr_cpus_allowed <= 1);
+
+       BUG_ON(!p->se.on_rq);
+       BUG_ON(!rt_task(p));
+
+       return p;
+}
+
 /*
  * If the current CPU has more than one RT task, see if the non
  * running task can migrate over to a CPU that is running a task
@@ -826,13 +1280,11 @@ static int push_rt_task(struct rq *rq)
 {
        struct task_struct *next_task;
        struct rq *lowest_rq;
-       int ret = 0;
-       int paranoid = RT_MAX_TRIES;
 
        if (!rq->rt.overloaded)
                return 0;
 
-       next_task = pick_next_highest_task_rt(rq, -1);
+       next_task = pick_next_pushable_task(rq);
        if (!next_task)
                return 0;
 
@@ -861,16 +1313,34 @@ static int push_rt_task(struct rq *rq)
                struct task_struct *task;
                /*
                 * find lock_lowest_rq releases rq->lock
-                * so it is possible that next_task has changed.
-                * If it has, then try again.
+                * so it is possible that next_task has migrated.
+                *
+                * We need to make sure that the task is still on the same
+                * run-queue and is also still the next task eligible for
+                * pushing.
                 */
-               task = pick_next_highest_task_rt(rq, -1);
-               if (unlikely(task != next_task) && task && paranoid--) {
-                       put_task_struct(next_task);
-                       next_task = task;
-                       goto retry;
+               task = pick_next_pushable_task(rq);
+               if (task_cpu(next_task) == rq->cpu && task == next_task) {
+                       /*
+                        * If we get here, the task hasnt moved at all, but
+                        * it has failed to push.  We will not try again,
+                        * since the other cpus will pull from us when they
+                        * are ready.
+                        */
+                       dequeue_pushable_task(rq, next_task);
+                       goto out;
                }
-               goto out;
+
+               if (!task)
+                       /* No more tasks, just exit */
+                       goto out;
+
+               /*
+                * Something has shifted, try again.
+                */
+               put_task_struct(next_task);
+               next_task = task;
+               goto retry;
        }
 
        deactivate_task(rq, next_task, 0);
@@ -879,25 +1349,14 @@ static int push_rt_task(struct rq *rq)
 
        resched_task(lowest_rq->curr);
 
-       spin_unlock(&lowest_rq->lock);
+       double_unlock_balance(rq, lowest_rq);
 
-       ret = 1;
 out:
        put_task_struct(next_task);
 
-       return ret;
+       return 1;
 }
 
-/*
- * TODO: Currently we just use the second highest prio task on
- *       the queue, and stop when it can't migrate (or there's
- *       no more RT tasks).  There may be a case where a lower
- *       priority RT task has a different affinity than the
- *       higher RT task. In this case the lower RT task could
- *       possibly be able to migrate where as the higher priority
- *       RT task could not.  We currently ignore this issue.
- *       Enhancements are welcome!
- */
 static void push_rt_tasks(struct rq *rq)
 {
        /* push_rt_task will return true if it moved an RT */
@@ -908,33 +1367,35 @@ static void push_rt_tasks(struct rq *rq)
 static int pull_rt_task(struct rq *this_rq)
 {
        int this_cpu = this_rq->cpu, ret = 0, cpu;
-       struct task_struct *p, *next;
+       struct task_struct *p;
        struct rq *src_rq;
 
        if (likely(!rt_overloaded(this_rq)))
                return 0;
 
-       next = pick_next_task_rt(this_rq);
-
-       for_each_cpu_mask(cpu, this_rq->rd->rto_mask) {
+       for_each_cpu(cpu, this_rq->rd->rto_mask) {
                if (this_cpu == cpu)
                        continue;
 
                src_rq = cpu_rq(cpu);
+
+               /*
+                * Don't bother taking the src_rq->lock if the next highest
+                * task is known to be lower-priority than our current task.
+                * This may look racy, but if this value is about to go
+                * logically higher, the src_rq will push this task away.
+                * And if its going logically lower, we do not care
+                */
+               if (src_rq->rt.highest_prio.next >=
+                   this_rq->rt.highest_prio.curr)
+                       continue;
+
                /*
                 * We can potentially drop this_rq's lock in
                 * double_lock_balance, and another CPU could
-                * steal our next task - hence we must cause
-                * the caller to recalculate the next task
-                * in that case:
+                * alter this_rq
                 */
-               if (double_lock_balance(this_rq, src_rq)) {
-                       struct task_struct *old_next = next;
-
-                       next = pick_next_task_rt(this_rq);
-                       if (next != old_next)
-                               ret = 1;
-               }
+               double_lock_balance(this_rq, src_rq);
 
                /*
                 * Are there still pullable RT tasks?
@@ -948,7 +1409,7 @@ static int pull_rt_task(struct rq *this_rq)
                 * Do we have an RT task that preempts
                 * the to-be-scheduled task?
                 */
-               if (p && (!next || (p->prio < next->prio))) {
+               if (p && (p->prio < this_rq->rt.highest_prio.curr)) {
                        WARN_ON(p == src_rq->curr);
                        WARN_ON(!p->se.on_rq);
 
@@ -958,12 +1419,9 @@ static int pull_rt_task(struct rq *this_rq)
                         * This is just that p is wakeing up and hasn't
                         * had a chance to schedule. We only pull
                         * p if it is lower in priority than the
-                        * current task on the run queue or
-                        * this_rq next task is lower in prio than
-                        * the current task on that rq.
+                        * current task on the run queue
                         */
-                       if (p->prio < src_rq->curr->prio ||
-                           (next && next->prio < src_rq->curr->prio))
+                       if (p->prio < src_rq->curr->prio)
                                goto skip;
 
                        ret = 1;
@@ -976,16 +1434,10 @@ static int pull_rt_task(struct rq *this_rq)
                         * case there's an even higher prio task
                         * in another runqueue. (low likelyhood
                         * but possible)
-                        *
-                        * Update next so that we won't pick a task
-                        * on another cpu with a priority lower (or equal)
-                        * than the one we just picked.
                         */
-                       next = p;
-
                }
  skip:
-               spin_unlock(&src_rq->lock);
+               double_unlock_balance(this_rq, src_rq);
        }
 
        return ret;
@@ -994,32 +1446,39 @@ static int pull_rt_task(struct rq *this_rq)
 static void pre_schedule_rt(struct rq *rq, struct task_struct *prev)
 {
        /* Try to pull RT tasks here if we lower this rq's prio */
-       if (unlikely(rt_task(prev)) && rq->rt.highest_prio > prev->prio)
+       if (unlikely(rt_task(prev)) && rq->rt.highest_prio.curr > prev->prio)
                pull_rt_task(rq);
 }
 
+/*
+ * assumes rq->lock is held
+ */
+static int needs_post_schedule_rt(struct rq *rq)
+{
+       return has_pushable_tasks(rq);
+}
+
 static void post_schedule_rt(struct rq *rq)
 {
        /*
-        * If we have more than one rt_task queued, then
-        * see if we can push the other rt_tasks off to other CPUS.
-        * Note we may release the rq lock, and since
-        * the lock was owned by prev, we need to release it
-        * first via finish_lock_switch and then reaquire it here.
+        * This is only called if needs_post_schedule_rt() indicates that
+        * we need to push tasks away
         */
-       if (unlikely(rq->rt.overloaded)) {
-               spin_lock_irq(&rq->lock);
-               push_rt_tasks(rq);
-               spin_unlock_irq(&rq->lock);
-       }
+       spin_lock_irq(&rq->lock);
+       push_rt_tasks(rq);
+       spin_unlock_irq(&rq->lock);
 }
 
-
+/*
+ * If we are not running and we are not going to reschedule soon, we should
+ * try to push tasks away now
+ */
 static void task_wake_up_rt(struct rq *rq, struct task_struct *p)
 {
        if (!task_running(rq, p) &&
-           (p->prio >= rq->rt.highest_prio) &&
-           rq->rt.overloaded)
+           !test_tsk_need_resched(rq->curr) &&
+           has_pushable_tasks(rq) &&
+           p->rt.nr_cpus_allowed > 1)
                push_rt_tasks(rq);
 }
 
@@ -1041,9 +1500,10 @@ move_one_task_rt(struct rq *this_rq, int this_cpu, struct rq *busiest,
        return 0;
 }
 
-static void set_cpus_allowed_rt(struct task_struct *p, cpumask_t *new_mask)
+static void set_cpus_allowed_rt(struct task_struct *p,
+                               const struct cpumask *new_mask)
 {
-       int weight = cpus_weight(*new_mask);
+       int weight = cpumask_weight(new_mask);
 
        BUG_ON(!rt_task(p));
 
@@ -1054,6 +1514,24 @@ static void set_cpus_allowed_rt(struct task_struct *p, cpumask_t *new_mask)
        if (p->se.on_rq && (weight != p->rt.nr_cpus_allowed)) {
                struct rq *rq = task_rq(p);
 
+               if (!task_current(rq, p)) {
+                       /*
+                        * Make sure we dequeue this task from the pushable list
+                        * before going further.  It will either remain off of
+                        * the list because we are no longer pushable, or it
+                        * will be requeued.
+                        */
+                       if (p->rt.nr_cpus_allowed > 1)
+                               dequeue_pushable_task(rq, p);
+
+                       /*
+                        * Requeue if our weight is changing and still > 1
+                        */
+                       if (weight > 1)
+                               enqueue_pushable_task(rq, p);
+
+               }
+
                if ((p->rt.nr_cpus_allowed <= 1) && (weight > 1)) {
                        rq->rt.rt_nr_migratory++;
                } else if ((p->rt.nr_cpus_allowed > 1) && (weight <= 1)) {
@@ -1061,25 +1539,33 @@ static void set_cpus_allowed_rt(struct task_struct *p, cpumask_t *new_mask)
                        rq->rt.rt_nr_migratory--;
                }
 
-               update_rt_migration(rq);
+               update_rt_migration(&rq->rt);
        }
 
-       p->cpus_allowed    = *new_mask;
+       cpumask_copy(&p->cpus_allowed, new_mask);
        p->rt.nr_cpus_allowed = weight;
 }
 
 /* Assumes rq->lock is held */
-static void join_domain_rt(struct rq *rq)
+static void rq_online_rt(struct rq *rq)
 {
        if (rq->rt.overloaded)
                rt_set_overload(rq);
+
+       __enable_runtime(rq);
+
+       cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr);
 }
 
 /* Assumes rq->lock is held */
-static void leave_domain_rt(struct rq *rq)
+static void rq_offline_rt(struct rq *rq)
 {
        if (rq->rt.overloaded)
                rt_clear_overload(rq);
+
+       __disable_runtime(rq);
+
+       cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID);
 }
 
 /*
@@ -1099,6 +1585,15 @@ static void switched_from_rt(struct rq *rq, struct task_struct *p,
        if (!rq->rt.rt_nr_running)
                pull_rt_task(rq);
 }
+
+static inline void init_sched_rt_class(void)
+{
+       unsigned int i;
+
+       for_each_possible_cpu(i)
+               zalloc_cpumask_var_node(&per_cpu(local_cpu_mask, i),
+                                       GFP_KERNEL, cpu_to_node(i));
+}
 #endif /* CONFIG_SMP */
 
 /*
@@ -1151,7 +1646,7 @@ static void prio_changed_rt(struct rq *rq, struct task_struct *p,
                 * can release the rq lock and p could migrate.
                 * Only reschedule if p is still on the same runqueue.
                 */
-               if (p->prio > rq->rt.highest_prio && rq->curr == p)
+               if (p->prio > rq->rt.highest_prio.curr && rq->curr == p)
                        resched_task(p);
 #else
                /* For UP simply resched on drop of prio */
@@ -1185,7 +1680,7 @@ static void watchdog(struct rq *rq, struct task_struct *p)
                p->rt.timeout++;
                next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ);
                if (p->rt.timeout > next)
-                       p->it_sched_expires = p->se.sum_exec_runtime;
+                       p->cputime_expires.sched_exp = p->se.sum_exec_runtime;
        }
 }
 
@@ -1212,7 +1707,7 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
         * on the queue:
         */
        if (p->rt.run_list.prev != p->rt.run_list.next) {
-               requeue_task_rt(rq, p);
+               requeue_task_rt(rq, p, 0);
                set_tsk_need_resched(p);
        }
 }
@@ -1222,16 +1717,16 @@ static void set_curr_task_rt(struct rq *rq)
        struct task_struct *p = rq->curr;
 
        p->se.exec_start = rq->clock;
+
+       /* The running task is never eligible for pushing */
+       dequeue_pushable_task(rq, p);
 }
 
-const struct sched_class rt_sched_class = {
+static const struct sched_class rt_sched_class = {
        .next                   = &fair_sched_class,
        .enqueue_task           = enqueue_task_rt,
        .dequeue_task           = dequeue_task_rt,
        .yield_task             = yield_task_rt,
-#ifdef CONFIG_SMP
-       .select_task_rq         = select_task_rq_rt,
-#endif /* CONFIG_SMP */
 
        .check_preempt_curr     = check_preempt_curr_rt,
 
@@ -1239,12 +1734,15 @@ const struct sched_class rt_sched_class = {
        .put_prev_task          = put_prev_task_rt,
 
 #ifdef CONFIG_SMP
+       .select_task_rq         = select_task_rq_rt,
+
        .load_balance           = load_balance_rt,
        .move_one_task          = move_one_task_rt,
        .set_cpus_allowed       = set_cpus_allowed_rt,
-       .join_domain            = join_domain_rt,
-       .leave_domain           = leave_domain_rt,
+       .rq_online              = rq_online_rt,
+       .rq_offline             = rq_offline_rt,
        .pre_schedule           = pre_schedule_rt,
+       .needs_post_schedule    = needs_post_schedule_rt,
        .post_schedule          = post_schedule_rt,
        .task_wake_up           = task_wake_up_rt,
        .switched_from          = switched_from_rt,
@@ -1256,3 +1754,18 @@ const struct sched_class rt_sched_class = {
        .prio_changed           = prio_changed_rt,
        .switched_to            = switched_to_rt,
 };
+
+#ifdef CONFIG_SCHED_DEBUG
+extern void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq);
+
+static void print_rt_stats(struct seq_file *m, int cpu)
+{
+       struct rt_rq *rt_rq;
+
+       rcu_read_lock();
+       for_each_leaf_rt_rq(rt_rq, cpu_rq(cpu))
+               print_rt_rq(m, cpu, rt_rq);
+       rcu_read_unlock();
+}
+#endif /* CONFIG_SCHED_DEBUG */
+