Merge branches 'sched/rt' and 'sched/urgent' into sched/core
[linux-2.6.git] / kernel / sched_rt.c
index 954e1a8..c79dc78 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)
@@ -37,25 +71,69 @@ static inline void rt_clear_overload(struct rq *rq)
        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)
 {
-       return container_of(rt_se, struct task_struct, rt);
 }
 
+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)
+{
+}
+
+#endif /* CONFIG_SMP */
+
 static inline int on_rt_rq(struct sched_rt_entity *rt_se)
 {
        return !list_empty(&rt_se->run_list);
@@ -79,16 +157,6 @@ static inline u64 sched_rt_period(struct rt_rq *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)
 
-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;
-}
-
 #define for_each_sched_rt_entity(rt_se) \
        for (; rt_se; rt_se = rt_se->parent)
 
@@ -108,7 +176,7 @@ static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
        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)
+               if (rt_rq->highest_prio.curr < curr->prio)
                        resched_task(curr);
        }
 }
@@ -176,19 +244,6 @@ static inline u64 sched_rt_period(struct rt_rq *rt_rq)
 #define for_each_leaf_rt_rq(rt_rq, rq) \
        for (rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
 
-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;
-}
-
 #define for_each_sched_rt_entity(rt_se) \
        for (; rt_se; rt_se = NULL)
 
@@ -473,7 +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;
@@ -547,91 +602,174 @@ static void update_curr_rt(struct rq *rq)
        }
 }
 
-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++;
-#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
+       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;
 
-               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);
+                       cpupri_set(&rq->rd->cpupri, rq->cpu, prio);
 
-               rq->rt.rt_nr_migratory++;
-       }
+       } 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);
+}
 
-       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++;
+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->tg)
-               start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
-#else
-       start_rt_bandwidth(&def_rt_bandwidth);
-#endif
+       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 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
+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 */
 
-       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
+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) {
-               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 =
+               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);
-               } /* 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--;
-       }
+               rt_rq->highest_prio.curr = MAX_RT_PRIO;
 
-       if (rt_rq->highest_prio != highest_prio) {
-               struct rq *rq = rq_of_rt_rq(rt_rq);
+       dec_rt_prio_smp(rt_rq, prio, prev_prio);
+}
 
-               if (rq->online)
-                       cpupri_set(&rq->rd->cpupri, rq->cpu,
-                                  rt_rq->highest_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 /* CONFIG_SMP */
 #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);
+}
+
+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);
-#endif
+}
+
+#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);
+}
+
+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
+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--;
+
+       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)
@@ -718,6 +856,9 @@ static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup)
 
        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);
 }
 
@@ -728,6 +869,8 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep)
        update_curr_rt(rq);
        dequeue_rt_entity(rt_se);
 
+       dequeue_pushable_task(rq, p);
+
        dec_cpu_load(rq, p->se.load.weight);
 }
 
@@ -878,7 +1021,7 @@ 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;
@@ -900,6 +1043,18 @@ 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;
 }
 
@@ -907,6 +1062,13 @@ 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
@@ -968,8 +1130,8 @@ static inline int pick_optimal_cpu(int this_cpu, cpumask_t *mask)
        if ((this_cpu != -1) && cpu_isset(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;
@@ -1072,7 +1234,7 @@ 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 */
@@ -1083,6 +1245,31 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
        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
@@ -1092,13 +1279,11 @@ 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;
 
@@ -1127,16 +1312,34 @@ 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);
@@ -1147,23 +1350,12 @@ static int push_rt_task(struct rq *rq)
 
        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 */
@@ -1174,33 +1366,35 @@ 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(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?
@@ -1214,7 +1408,7 @@ 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);
 
@@ -1224,12 +1418,9 @@ 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;
@@ -1242,13 +1433,7 @@ 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:
                double_unlock_balance(this_rq, src_rq);
@@ -1260,24 +1445,27 @@ 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);
 }
 
 /*
@@ -1288,7 +1476,8 @@ static void task_wake_up_rt(struct rq *rq, struct task_struct *p)
 {
        if (!task_running(rq, p) &&
            !test_tsk_need_resched(rq->curr) &&
-           rq->rt.overloaded)
+           has_pushable_tasks(rq) &&
+           p->rt.nr_cpus_allowed > 1)
                push_rt_tasks(rq);
 }
 
@@ -1324,6 +1513,24 @@ static void set_cpus_allowed_rt(struct task_struct *p,
        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)) {
@@ -1331,7 +1538,7 @@ static void set_cpus_allowed_rt(struct task_struct *p,
                        rq->rt.rt_nr_migratory--;
                }
 
-               update_rt_migration(rq);
+               update_rt_migration(&rq->rt);
        }
 
        cpumask_copy(&p->cpus_allowed, new_mask);
@@ -1346,7 +1553,7 @@ static void rq_online_rt(struct rq *rq)
 
        __enable_runtime(rq);
 
-       cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio);
+       cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr);
 }
 
 /* Assumes rq->lock is held */
@@ -1438,7 +1645,7 @@ 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 */
@@ -1509,6 +1716,9 @@ 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);
 }
 
 static const struct sched_class rt_sched_class = {
@@ -1531,6 +1741,7 @@ static const struct sched_class rt_sched_class = {
        .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,