Merge branch 'sched/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip...

[pandora-kernel.git] / kernel / sched_rt.c

diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 7c96147..f85a763 100644 (file)
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -505,7 +505,9 @@ void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
        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
 
                rt_rq->highest_prio = rt_se_prio(rt_se);
 #ifdef CONFIG_SMP
@@ -599,11 +601,7 @@ static void __enqueue_rt_entity(struct sched_rt_entity *rt_se)
        if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running))
                return;
 
-       if (rt_se->nr_cpus_allowed == 1)
-               list_add(&rt_se->run_list, queue);
-       else
-               list_add_tail(&rt_se->run_list, queue);
-
+       list_add_tail(&rt_se->run_list, queue);
        __set_bit(rt_se_prio(rt_se), array->bitmap);
 
        inc_rt_tasks(rt_se, rt_rq);
@@ -688,32 +686,34 @@ 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;
-
        if (on_rt_rq(rt_se)) {
-               list_del_init(&rt_se->run_list);
-               list_add_tail(&rt_se->run_list,
-                             array->queue + rt_se_prio(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
@@ -753,6 +753,30 @@ 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 */
 
 /*
@@ -778,18 +802,8 @@ static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p)
         * to move current somewhere else, making room for our non-migratable
         * task.
         */
-       if((p->prio == rq->curr->prio)
-          && p->rt.nr_cpus_allowed == 1
-          && rq->curr->rt.nr_cpus_allowed != 1) {
-               cpumask_t mask;
-
-               if (cpupri_find(&rq->rd->cpupri, rq->curr, &mask))
-                       /*
-                        * There appears to be other cpus that can accept
-                        * current, so lets reschedule to try and push it away
-                        */
-                       resched_task(rq->curr);
-       }
+       if (p->prio == rq->curr->prio && !need_resched())
+               check_preempt_equal_prio(rq, p);
 #endif
 }
 
@@ -921,6 +935,13 @@ static int find_lowest_rq(struct task_struct *task)
        if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask))
                return -1; /* No targets 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.
+        */
+       cpus_and(*lowest_mask, *lowest_mask, cpu_active_map);
+
        /*
         * At this point we have built a mask of cpus representing the
         * lowest priority tasks in the system.  Now we want to elect
@@ -1415,7 +1436,7 @@ 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);
        }
 }