[libata] pata_rb532_cf: fix signature of the xfer function
[linux-2.6.git] / kernel / sched_rt.c
index 1178257..d9ba9d5 100644 (file)
@@ -12,6 +12,9 @@ static inline int rt_overloaded(struct rq *rq)
 
 static inline void rt_set_overload(struct rq *rq)
 {
+       if (!rq->online)
+               return;
+
        cpu_set(rq->cpu, rq->rd->rto_mask);
        /*
         * Make sure the mask is visible before we set
@@ -26,6 +29,9 @@ 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);
@@ -55,14 +61,19 @@ static inline int on_rt_rq(struct sched_rt_entity *rt_se)
        return !list_empty(&rt_se->run_list);
 }
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_RT_GROUP_SCHED
 
-static inline unsigned int sched_rt_ratio(struct rt_rq *rt_rq)
+static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
 {
        if (!rt_rq->tg)
-               return SCHED_RT_FRAC;
+               return RUNTIME_INF;
+
+       return rt_rq->rt_runtime;
+}
 
-       return rt_rq->tg->rt_ratio;
+static inline u64 sched_rt_period(struct rt_rq *rt_rq)
+{
+       return ktime_to_ns(rt_rq->tg->rt_bandwidth.rt_period);
 }
 
 #define for_each_leaf_rt_rq(rt_rq, rq) \
@@ -89,17 +100,20 @@ static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
 static void enqueue_rt_entity(struct sched_rt_entity *rt_se);
 static void dequeue_rt_entity(struct sched_rt_entity *rt_se);
 
-static void sched_rt_ratio_enqueue(struct rt_rq *rt_rq)
+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) {
-               enqueue_rt_entity(rt_se);
-               resched_task(rq_of_rt_rq(rt_rq)->curr);
+       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->prio)
+                       resched_task(curr);
        }
 }
 
-static void sched_rt_ratio_dequeue(struct rt_rq *rt_rq)
+static void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
 {
        struct sched_rt_entity *rt_se = rt_rq->rt_se;
 
@@ -107,11 +121,56 @@ static void sched_rt_ratio_dequeue(struct rt_rq *rt_rq)
                dequeue_rt_entity(rt_se);
 }
 
+static inline int rt_rq_throttled(struct rt_rq *rt_rq)
+{
+       return rt_rq->rt_throttled && !rt_rq->rt_nr_boosted;
+}
+
+static int rt_se_boosted(struct sched_rt_entity *rt_se)
+{
+       struct rt_rq *rt_rq = group_rt_rq(rt_se);
+       struct task_struct *p;
+
+       if (rt_rq)
+               return !!rt_rq->rt_nr_boosted;
+
+       p = rt_task_of(rt_se);
+       return p->prio != p->normal_prio;
+}
+
+#ifdef CONFIG_SMP
+static inline cpumask_t sched_rt_period_mask(void)
+{
+       return cpu_rq(smp_processor_id())->rd->span;
+}
 #else
+static inline cpumask_t sched_rt_period_mask(void)
+{
+       return cpu_online_map;
+}
+#endif
+
+static inline
+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];
+}
+
+static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
+{
+       return &rt_rq->tg->rt_bandwidth;
+}
+
+#else /* !CONFIG_RT_GROUP_SCHED */
+
+static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
+{
+       return rt_rq->rt_runtime;
+}
 
-static inline unsigned int sched_rt_ratio(struct rt_rq *rt_rq)
+static inline u64 sched_rt_period(struct rt_rq *rt_rq)
 {
-       return sysctl_sched_rt_ratio;
+       return ktime_to_ns(def_rt_bandwidth.rt_period);
 }
 
 #define for_each_leaf_rt_rq(rt_rq, rq) \
@@ -138,75 +197,312 @@ static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
        return NULL;
 }
 
-static inline void sched_rt_ratio_enqueue(struct rt_rq *rt_rq)
+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_ratio_dequeue(struct rt_rq *rt_rq)
+static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
 {
 }
 
-#endif
+static inline int rt_rq_throttled(struct rt_rq *rt_rq)
+{
+       return rt_rq->rt_throttled;
+}
 
-static inline int rt_se_prio(struct sched_rt_entity *rt_se)
+static inline cpumask_t sched_rt_period_mask(void)
 {
-#ifdef CONFIG_FAIR_GROUP_SCHED
-       struct rt_rq *rt_rq = group_rt_rq(rt_se);
+       return cpu_online_map;
+}
 
-       if (rt_rq)
-               return rt_rq->highest_prio;
-#endif
+static inline
+struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
+{
+       return &cpu_rq(cpu)->rt;
+}
 
-       return rt_task_of(rt_se)->prio;
+static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
+{
+       return &def_rt_bandwidth;
 }
 
-static int sched_rt_ratio_exceeded(struct rt_rq *rt_rq)
+#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)
 {
-       unsigned int rt_ratio = sched_rt_ratio(rt_rq);
-       u64 period, ratio;
+       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;
 
-       if (rt_ratio == SCHED_RT_FRAC)
-               return 0;
+       weight = cpus_weight(rd->span);
 
-       if (rt_rq->rt_throttled)
-               return 1;
+       spin_lock(&rt_b->rt_runtime_lock);
+       rt_period = ktime_to_ns(rt_b->rt_period);
+       for_each_cpu_mask_nr(i, rd->span) {
+               struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
+               s64 diff;
 
-       period = (u64)sysctl_sched_rt_period * NSEC_PER_MSEC;
-       ratio = (period * rt_ratio) >> SCHED_RT_FRAC_SHIFT;
+               if (iter == rt_rq)
+                       continue;
 
-       if (rt_rq->rt_time > ratio) {
-               rt_rq->rt_throttled = 1;
-               sched_rt_ratio_dequeue(rt_rq);
-               return 1;
+               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 0;
+       return more;
 }
 
-static void __update_sched_rt_period(struct rt_rq *rt_rq, u64 period)
+/*
+ * Ensure this RQ takes back all the runtime it lend to its neighbours.
+ */
+static void __disable_runtime(struct rq *rq)
 {
-       unsigned long rt_ratio = sched_rt_ratio(rt_rq);
-       u64 ratio = (period * rt_ratio) >> SCHED_RT_FRAC_SHIFT;
+       struct root_domain *rd = rq->rd;
+       struct rt_rq *rt_rq;
 
-       rt_rq->rt_time -= min(rt_rq->rt_time, ratio);
-       if (rt_rq->rt_throttled) {
-               rt_rq->rt_throttled = 0;
-               sched_rt_ratio_enqueue(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_mask(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 update_sched_rt_period(struct rq *rq)
+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;
-       u64 period;
 
-       while (rq->clock > rq->rt_period_expire) {
-               period = (u64)sysctl_sched_rt_period * NSEC_PER_MSEC;
-               rq->rt_period_expire += period;
+       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;
+
+       if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
+               return 1;
+
+       span = sched_rt_period_mask();
+       for_each_cpu_mask(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;
+
+                       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;
+                               enqueue = 1;
+                       }
+                       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);
+               spin_unlock(&rq->lock);
+       }
+
+       return idle;
+}
+
+static inline int rt_se_prio(struct sched_rt_entity *rt_se)
+{
+#ifdef CONFIG_RT_GROUP_SCHED
+       struct rt_rq *rt_rq = group_rt_rq(rt_se);
+
+       if (rt_rq)
+               return rt_rq->highest_prio;
+#endif
+
+       return rt_task_of(rt_se)->prio;
+}
+
+static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
+{
+       u64 runtime = sched_rt_runtime(rt_rq);
+
+       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;
 
-               for_each_leaf_rt_rq(rt_rq, rq)
-                       __update_sched_rt_period(rt_rq, period);
+       if (rt_rq->rt_time > runtime) {
+               rt_rq->rt_throttled = 1;
+               if (rt_rq_throttled(rt_rq)) {
+                       sched_rt_rq_dequeue(rt_rq);
+                       return 1;
+               }
        }
+
+       return 0;
 }
 
 /*
@@ -230,17 +526,25 @@ 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;
-       /*
-        * might make it a tad more accurate:
-        *
-        * update_sched_rt_period(rq);
-        */
-       if (sched_rt_ratio_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);
+
+               spin_lock(&rt_rq->rt_runtime_lock);
+               if (sched_rt_runtime(rt_rq) != RUNTIME_INF) {
+                       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
@@ -248,27 +552,51 @@ void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
 {
        WARN_ON(!rt_prio(rt_se_prio(rt_se)));
        rt_rq->rt_nr_running++;
-#if defined CONFIG_SMP || defined CONFIG_FAIR_GROUP_SCHED
-       if (rt_se_prio(rt_se) < rt_rq->highest_prio)
+#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
+       if (rt_se_prio(rt_se) < rt_rq->highest_prio) {
+#ifdef CONFIG_SMP
+               struct rq *rq = rq_of_rt_rq(rt_rq);
+#endif
+
                rt_rq->highest_prio = rt_se_prio(rt_se);
+#ifdef CONFIG_SMP
+               if (rq->online)
+                       cpupri_set(&rq->rd->cpupri, rq->cpu,
+                                  rt_se_prio(rt_se));
+#endif
+       }
 #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
+#ifdef CONFIG_RT_GROUP_SCHED
+       if (rt_se_boosted(rt_se))
+               rt_rq->rt_nr_boosted++;
+
+       if (rt_rq->tg)
+               start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
+#else
+       start_rt_bandwidth(&def_rt_bandwidth);
+#endif
 }
 
 static inline
 void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
 {
+#ifdef CONFIG_SMP
+       int highest_prio = rt_rq->highest_prio;
+#endif
+
        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_FAIR_GROUP_SCHED
+#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
        if (rt_rq->rt_nr_running) {
                struct rt_prio_array *array;
 
@@ -288,26 +616,47 @@ void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
                rq->rt.rt_nr_migratory--;
        }
 
+       if (rt_rq->highest_prio != highest_prio) {
+               struct rq *rq = rq_of_rt_rq(rt_rq);
+
+               if (rq->online)
+                       cpupri_set(&rq->rd->cpupri, rq->cpu,
+                                  rt_rq->highest_prio);
+       }
+
        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
 }
 
-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 && group_rq->rt_throttled)
+       /*
+        * 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;
@@ -322,27 +671,39 @@ 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);
+       }
 }
 
 /*
@@ -355,13 +716,7 @@ 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 everybody, bottom - up.
-        */
-       for_each_sched_rt_entity(rt_se)
-               enqueue_rt_entity(rt_se);
+       enqueue_rt_entity(rt_se);
 
        inc_cpu_load(rq, p->se.load.weight);
 }
@@ -369,20 +724,9 @@ static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup)
 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_stack(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);
-       }
+       dequeue_rt_entity(rt_se);
 
        dec_cpu_load(rq, p->se.load.weight);
 }
@@ -391,28 +735,34 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep)
  * 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;
-
-       list_move_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se));
+       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);
+
+               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
@@ -452,15 +802,58 @@ 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)
+{
+       cpumask_t mask;
+
+       if (rq->curr->rt.nr_cpus_allowed == 1)
+               return;
+
+       if (p->rt.nr_cpus_allowed != 1
+           && cpupri_find(&rq->rd->cpupri, p, &mask))
+               return;
+
+       if (!cpupri_find(&rq->rd->cpupri, rq->curr, &mask))
+               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,
@@ -471,15 +864,12 @@ static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
        struct list_head *queue;
        int idx;
 
-       if (sched_rt_ratio_exceeded(rt_rq))
-               goto out;
-
        idx = sched_find_first_bit(array->bitmap);
        BUG_ON(idx >= MAX_RT_PRIO);
 
        queue = array->queue + idx;
        next = list_entry(queue->next, struct sched_rt_entity, run_list);
- out:
+
        return next;
 }
 
@@ -489,19 +879,17 @@ static struct task_struct *pick_next_task_rt(struct rq *rq)
        struct task_struct *p;
        struct rt_rq *rt_rq;
 
- retry:
        rt_rq = &rq->rt;
 
        if (unlikely(!rt_rq->rt_nr_running))
                return NULL;
 
-       if (sched_rt_ratio_exceeded(rt_rq))
+       if (rt_rq_throttled(rt_rq))
                return NULL;
 
        do {
                rt_se = pick_next_rt_entity(rq, rt_rq);
-               if (unlikely(!rt_se))
-                       goto retry;
+               BUG_ON(!rt_se);
                rt_rq = group_rt_rq(rt_se);
        } while (rt_rq);
 
@@ -522,6 +910,8 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
 #define RT_MAX_TRIES 3
 
 static int double_lock_balance(struct rq *this_rq, struct rq *busiest);
+static void double_unlock_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)
@@ -568,73 +958,6 @@ static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu)
 
 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);
-       }
-
-       /*
-        * 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)
 {
        int first;
@@ -656,17 +979,19 @@ static int find_lowest_rq(struct task_struct *task)
        cpumask_t *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);
 
-       if (!count)
+       if (task->rt.nr_cpus_allowed == 1)
+               return -1; /* No other targets possible */
+
+       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);
+       cpus_and(*lowest_mask, *lowest_mask, cpu_active_map);
 
        /*
         * At this point we have built a mask of cpus representing the
@@ -748,7 +1073,7 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
                        break;
 
                /* try again */
-               spin_unlock(&lowest_rq->lock);
+               double_unlock_balance(rq, lowest_rq);
                lowest_rq = NULL;
        }
 
@@ -817,7 +1142,7 @@ 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:
@@ -854,7 +1179,7 @@ static int pull_rt_task(struct rq *this_rq)
 
        next = pick_next_task_rt(this_rq);
 
-       for_each_cpu_mask(cpu, this_rq->rd->rto_mask) {
+       for_each_cpu_mask_nr(cpu, this_rq->rd->rto_mask) {
                if (this_cpu == cpu)
                        continue;
 
@@ -877,10 +1202,8 @@ static int pull_rt_task(struct rq *this_rq)
                /*
                 * Are there still pullable RT tasks?
                 */
-               if (src_rq->rt.rt_nr_running <= 1) {
-                       spin_unlock(&src_rq->lock);
-                       continue;
-               }
+               if (src_rq->rt.rt_nr_running <= 1)
+                       goto skip;
 
                p = pick_next_highest_task_rt(src_rq, this_cpu);
 
@@ -904,7 +1227,7 @@ static int pull_rt_task(struct rq *this_rq)
                         */
                        if (p->prio < src_rq->curr->prio ||
                            (next && next->prio < src_rq->curr->prio))
-                               goto out;
+                               goto skip;
 
                        ret = 1;
 
@@ -924,8 +1247,8 @@ static int pull_rt_task(struct rq *this_rq)
                        next = p;
 
                }
- out:
-               spin_unlock(&src_rq->lock);
+ skip:
+               double_unlock_balance(this_rq, src_rq);
        }
 
        return ret;
@@ -954,11 +1277,14 @@ static void post_schedule_rt(struct rq *rq)
        }
 }
 
-
+/*
+ * 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) &&
+           !test_tsk_need_resched(rq->curr) &&
            rq->rt.overloaded)
                push_rt_tasks(rq);
 }
@@ -981,7 +1307,8 @@ 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 cpumask_t *new_mask)
 {
        int weight = cpus_weight(*new_mask);
 
@@ -1009,17 +1336,25 @@ static void set_cpus_allowed_rt(struct task_struct *p, cpumask_t *new_mask)
 }
 
 /* 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);
 }
 
 /* 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);
 }
 
 /*
@@ -1087,9 +1422,11 @@ static void prio_changed_rt(struct rq *rq, struct task_struct *p,
                        pull_rt_task(rq);
                /*
                 * If there's a higher priority task waiting to run
-                * then reschedule.
+                * then reschedule. Note, the above pull_rt_task
+                * 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)
+               if (p->prio > rq->rt.highest_prio && rq->curr == p)
                        resched_task(p);
 #else
                /* For UP simply resched on drop of prio */
@@ -1122,14 +1459,8 @@ 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 (next > p->rt.timeout) {
-                       u64 next_time = p->se.sum_exec_runtime;
-
-                       next_time += next * (NSEC_PER_SEC/HZ);
-                       if (p->it_sched_expires > next_time)
-                               p->it_sched_expires = next_time;
-               } else
-                       p->it_sched_expires = p->se.sum_exec_runtime;
+               if (p->rt.timeout > next)
+                       p->cputime_expires.sched_exp = p->se.sum_exec_runtime;
        }
 }
 
@@ -1156,7 +1487,7 @@ 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);
        }
 }
@@ -1168,14 +1499,11 @@ static void set_curr_task_rt(struct rq *rq)
        p->se.exec_start = rq->clock;
 }
 
-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,
 
@@ -1183,11 +1511,13 @@ 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,
        .post_schedule          = post_schedule_rt,
        .task_wake_up           = task_wake_up_rt,
@@ -1200,3 +1530,17 @@ 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 */