Merge branch 'sched/urgent' into sched/core

[linux-2.6-microblaze.git] / kernel / sched / rt.c

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 1999021..facc824 100644 (file)
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -229,6 +229,14 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
 
 #ifdef CONFIG_SMP
 
+static int pull_rt_task(struct rq *this_rq);
+
+static inline bool need_pull_rt_task(struct rq *rq, struct task_struct *prev)
+{
+       /* Try to pull RT tasks here if we lower this rq's prio */
+       return rq->rt.highest_prio.curr > prev->prio;
+}
+
 static inline int rt_overloaded(struct rq *rq)
 {
        return atomic_read(&rq->rd->rto_count);
@@ -315,6 +323,15 @@ static inline int has_pushable_tasks(struct rq *rq)
        return !plist_head_empty(&rq->rt.pushable_tasks);
 }
 
+static inline void set_post_schedule(struct rq *rq)
+{
+       /*
+        * We detect this state here so that we can avoid taking the RQ
+        * lock again later if there is no need to push
+        */
+       rq->post_schedule = has_pushable_tasks(rq);
+}
+
 static void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
 {
        plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
@@ -359,6 +376,19 @@ void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
 {
 }
 
+static inline bool need_pull_rt_task(struct rq *rq, struct task_struct *prev)
+{
+       return false;
+}
+
+static inline int pull_rt_task(struct rq *this_rq)
+{
+       return 0;
+}
+
+static inline void set_post_schedule(struct rq *rq)
+{
+}
 #endif /* CONFIG_SMP */
 
 static inline int on_rt_rq(struct sched_rt_entity *rt_se)
@@ -1318,15 +1348,7 @@ static struct task_struct *_pick_next_task_rt(struct rq *rq)
 {
        struct sched_rt_entity *rt_se;
        struct task_struct *p;
-       struct rt_rq *rt_rq;
-
-       rt_rq = &rq->rt;
-
-       if (!rt_rq->rt_nr_running)
-               return NULL;
-
-       if (rt_rq_throttled(rt_rq))
-               return NULL;
+       struct rt_rq *rt_rq  = &rq->rt;
 
        do {
                rt_se = pick_next_rt_entity(rq, rt_rq);
@@ -1340,21 +1362,38 @@ static struct task_struct *_pick_next_task_rt(struct rq *rq)
        return p;
 }
 
-static struct task_struct *pick_next_task_rt(struct rq *rq)
+static struct task_struct *
+pick_next_task_rt(struct rq *rq, struct task_struct *prev)
 {
-       struct task_struct *p = _pick_next_task_rt(rq);
+       struct task_struct *p;
+       struct rt_rq *rt_rq = &rq->rt;
+
+       if (need_pull_rt_task(rq, prev)) {
+               pull_rt_task(rq);
+               /*
+                * pull_rt_task() can drop (and re-acquire) rq->lock; this
+                * means a dl task can slip in, in which case we need to
+                * re-start task selection.
+                */
+               if (unlikely(rq->dl.dl_nr_running))
+                       return RETRY_TASK;
+       }
+
+       if (!rt_rq->rt_nr_running)
+               return NULL;
+
+       if (rt_rq_throttled(rt_rq))
+               return NULL;
+
+       put_prev_task(rq, prev);
+
+       p = _pick_next_task_rt(rq);
 
        /* The running task is never eligible for pushing */
        if (p)
                dequeue_pushable_task(rq, p);
 
-#ifdef CONFIG_SMP
-       /*
-        * We detect this state here so that we can avoid taking the RQ
-        * lock again later if there is no need to push
-        */
-       rq->post_schedule = has_pushable_tasks(rq);
-#endif
+       set_post_schedule(rq);
 
        return p;
 }
@@ -1724,13 +1763,6 @@ skip:
        return ret;
 }
 
-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 (rq->rt.highest_prio.curr > prev->prio)
-               pull_rt_task(rq);
-}
-
 static void post_schedule_rt(struct rq *rq)
 {
        push_rt_tasks(rq);
@@ -1833,7 +1865,7 @@ static void switched_from_rt(struct rq *rq, struct task_struct *p)
                resched_task(rq->curr);
 }
 
-void init_sched_rt_class(void)
+void __init init_sched_rt_class(void)
 {
        unsigned int i;
 
@@ -2007,7 +2039,6 @@ const struct sched_class rt_sched_class = {
        .set_cpus_allowed       = set_cpus_allowed_rt,
        .rq_online              = rq_online_rt,
        .rq_offline             = rq_offline_rt,
-       .pre_schedule           = pre_schedule_rt,
        .post_schedule          = post_schedule_rt,
        .task_woken             = task_woken_rt,
        .switched_from          = switched_from_rt,