Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[safe/jmp/linux-2.6] / kernel / sched_rt.c
index 8ae3416..1113157 100644 (file)
@@ -161,7 +161,7 @@ static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
        return &rt_rq->tg->rt_bandwidth;
 }
 
-#else
+#else /* !CONFIG_RT_GROUP_SCHED */
 
 static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
 {
@@ -199,6 +199,8 @@ 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)
@@ -226,48 +228,10 @@ static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
        return &def_rt_bandwidth;
 }
 
-#endif
-
-static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
-{
-       int i, idle = 1;
-       cpumask_t span;
-
-       if (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);
-                       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);
-               }
-
-               if (enqueue)
-                       sched_rt_rq_enqueue(rt_rq);
-               spin_unlock(&rq->lock);
-       }
-
-       return idle;
-}
+#endif /* CONFIG_RT_GROUP_SCHED */
 
 #ifdef CONFIG_SMP
-static int balance_runtime(struct rt_rq *rt_rq)
+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;
@@ -278,7 +242,7 @@ static int balance_runtime(struct rt_rq *rt_rq)
 
        spin_lock(&rt_b->rt_runtime_lock);
        rt_period = ktime_to_ns(rt_b->rt_period);
-       for_each_cpu_mask(i, rd->span) {
+       for_each_cpu_mask_nr(i, rd->span) {
                struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
                s64 diff;
 
@@ -291,7 +255,7 @@ static int balance_runtime(struct rt_rq *rt_rq)
 
                diff = iter->rt_runtime - iter->rt_time;
                if (diff > 0) {
-                       do_div(diff, weight);
+                       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;
@@ -336,7 +300,7 @@ static void __disable_runtime(struct rq *rq)
                        struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
                        s64 diff;
 
-                       if (iter == rt_rq)
+                       if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
                                continue;
 
                        spin_lock(&iter->rt_runtime_lock);
@@ -374,7 +338,6 @@ static void disable_runtime(struct rq *rq)
 
 static void __enable_runtime(struct rq *rq)
 {
-       struct root_domain *rd = rq->rd;
        struct rt_rq *rt_rq;
 
        if (unlikely(!scheduler_running))
@@ -387,6 +350,7 @@ static void __enable_runtime(struct rq *rq)
                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);
        }
@@ -401,7 +365,65 @@ static void enable_runtime(struct rq *rq)
        spin_unlock_irqrestore(&rq->lock, flags);
 }
 
-#endif
+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_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)
 {
@@ -419,26 +441,16 @@ 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;
 
-#ifdef CONFIG_SMP
-       if (rt_rq->rt_time > runtime) {
-               spin_unlock(&rt_rq->rt_runtime_lock);
-               balance_runtime(rt_rq);
-               spin_lock(&rt_rq->rt_runtime_lock);
-
-               runtime = sched_rt_runtime(rt_rq);
-               if (runtime == RUNTIME_INF)
-                       return 0;
-       }
-#endif
+       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;
@@ -479,9 +491,11 @@ static void update_curr_rt(struct rq *rq)
                rt_rq = rt_rq_of_se(rt_se);
 
                spin_lock(&rt_rq->rt_runtime_lock);
-               rt_rq->rt_time += delta_exec;
-               if (sched_rt_runtime_exceeded(rt_rq))
-                       resched_task(curr);
+               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);
        }
 }
@@ -493,7 +507,9 @@ 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
@@ -571,35 +587,35 @@ void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
 #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 && 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;
 
-       if (rt_se->nr_cpus_allowed == 1)
-               list_add_tail(&rt_se->run_list,
-                             array->xqueue + rt_se_prio(rt_se));
-       else
-               list_add_tail(&rt_se->run_list,
-                             array->squeue + 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;
 
        list_del_init(&rt_se->run_list);
-       if (list_empty(array->squeue + rt_se_prio(rt_se))
-           && list_empty(array->xqueue + rt_se_prio(rt_se)))
+       if (list_empty(array->queue + rt_se_prio(rt_se)))
                __clear_bit(rt_se_prio(rt_se), array->bitmap);
 
        dec_rt_tasks(rt_se, rt_rq);
@@ -609,11 +625,10 @@ 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.
  */
-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, *back = NULL;
+       struct sched_rt_entity *back = NULL;
 
-       rt_se = &p->rt;
        for_each_sched_rt_entity(rt_se) {
                rt_se->back = back;
                back = rt_se;
@@ -621,7 +636,26 @@ static void dequeue_rt_stack(struct task_struct *p)
 
        for (rt_se = back; rt_se; rt_se = rt_se->back) {
                if (on_rt_rq(rt_se))
-                       dequeue_rt_entity(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);
        }
 }
 
@@ -635,66 +669,53 @@ 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);
+       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);
-
-       /*
-        * 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.
- *
- * Note: We always enqueue the task to the shared-queue, regardless of its
- * previous position w.r.t. exclusive vs shared.  This is so that exclusive RR
- * tasks fairly round-robin with all tasks on the runqueue, not just other
- * exclusive tasks.
  */
-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_del_init(&rt_se->run_list);
-       list_add_tail(&rt_se->run_list, array->squeue + 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
@@ -734,10 +755,31 @@ static int select_task_rq_rt(struct task_struct *p, int sync)
         */
        return task_cpu(p);
 }
-#endif /* CONFIG_SMP */
 
-static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
-                                                  struct rt_rq *rt_rq);
+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:
@@ -762,19 +804,8 @@ 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
-          && pick_next_rt_entity(rq, &rq->rt) != &rq->curr->rt) {
-               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
 }
 
@@ -789,15 +820,8 @@ static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
        idx = sched_find_first_bit(array->bitmap);
        BUG_ON(idx >= MAX_RT_PRIO);
 
-       queue = array->xqueue + idx;
-       if (!list_empty(queue))
-               next = list_entry(queue->next, struct sched_rt_entity,
-                                 run_list);
-       else {
-               queue = array->squeue + idx;
-               next = list_entry(queue->next, struct sched_rt_entity,
-                                 run_list);
-       }
+       queue = array->queue + idx;
+       next = list_entry(queue->next, struct sched_rt_entity, run_list);
 
        return next;
 }
@@ -839,6 +863,8 @@ 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)
@@ -867,7 +893,7 @@ static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu)
                        continue;
                if (next && next->prio < idx)
                        continue;
-               list_for_each_entry(rt_se, array->squeue + idx, run_list) {
+               list_for_each_entry(rt_se, array->queue + idx, run_list) {
                        struct task_struct *p = rt_task_of(rt_se);
                        if (pick_rt_task(rq, p, cpu)) {
                                next = p;
@@ -914,6 +940,13 @@ static int find_lowest_rq(struct task_struct *task)
                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
         * the best one based on our affinity and topology.
@@ -993,7 +1026,7 @@ 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;
        }
 
@@ -1062,7 +1095,7 @@ 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:
@@ -1099,7 +1132,7 @@ 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;
 
@@ -1168,7 +1201,7 @@ static int pull_rt_task(struct rq *this_rq)
 
                }
  skip:
-               spin_unlock(&src_rq->lock);
+               double_unlock_balance(this_rq, src_rq);
        }
 
        return ret;
@@ -1249,14 +1282,6 @@ static void set_cpus_allowed_rt(struct task_struct *p,
                }
 
                update_rt_migration(rq);
-
-               if (unlikely(weight == 1 || p->rt.nr_cpus_allowed == 1))
-                       /*
-                        * If either the new or old weight is a "1", we need
-                        * to requeue to properly move between shared and
-                        * exclusive queues.
-                        */
-                       requeue_task_rt(rq, p);
        }
 
        p->cpus_allowed    = *new_mask;
@@ -1415,7 +1440,7 @@ 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);
        }
 }
@@ -1459,3 +1484,17 @@ static 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 */