1 files changed, 290 insertions, 146 deletions

diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 0f3c19197fa4..f85a76363eee 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -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);
@@ -155,7 +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)
 {
@@ -220,7 +226,160 @@ static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
         return &def_rt_bandwidth;
 }
 
-#endif
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+#ifdef CONFIG_SMP
+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;
+        int i, weight, more = 0;
+        u64 rt_period;
+
+        weight = cpus_weight(rd->span);
+
+        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;
+
+                if (iter == rt_rq)
+                        continue;
+
+                spin_lock(&iter->rt_runtime_lock);
+                if (iter->rt_runtime == RUNTIME_INF)
+                        goto next;
+
+                diff = iter->rt_runtime - iter->rt_time;
+                if (diff > 0) {
+                        do_div(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 more;
+}
+
+static void __disable_runtime(struct rq *rq)
+{
+        struct root_domain *rd = rq->rd;
+        struct rt_rq *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);
+                if (rt_rq->rt_runtime == RUNTIME_INF ||
+                                rt_rq->rt_runtime == rt_b->rt_runtime)
+                        goto balanced;
+                spin_unlock(&rt_rq->rt_runtime_lock);
+
+                want = rt_b->rt_runtime - rt_rq->rt_runtime;
+
+                for_each_cpu_mask(i, rd->span) {
+                        struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
+                        s64 diff;
+
+                        if (iter == rt_rq)
+                                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);
+                BUG_ON(want);
+balanced:
+                rt_rq->rt_runtime = RUNTIME_INF;
+                spin_unlock(&rt_rq->rt_runtime_lock);
+                spin_unlock(&rt_b->rt_runtime_lock);
+        }
+}
+
+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;
+
+        if (unlikely(!scheduler_running))
+                return;
+
+        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;
+                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)
 {
@@ -241,6 +400,8 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
                         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) {
@@ -261,47 +422,6 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
         return idle;
 }
 
-#ifdef CONFIG_SMP
-static int 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;
-        int i, weight, more = 0;
-        u64 rt_period;
-
-        weight = cpus_weight(rd->span);
-
-        spin_lock(&rt_b->rt_runtime_lock);
-        rt_period = ktime_to_ns(rt_b->rt_period);
-        for_each_cpu_mask(i, rd->span) {
-                struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
-                s64 diff;
-
-                if (iter == rt_rq)
-                        continue;
-
-                spin_lock(&iter->rt_runtime_lock);
-                diff = iter->rt_runtime - iter->rt_time;
-                if (diff > 0) {
-                        do_div(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;
-                        }
-                }
-                spin_unlock(&iter->rt_runtime_lock);
-        }
-        spin_unlock(&rt_b->rt_runtime_lock);
-
-        return more;
-}
-#endif
-
 static inline int rt_se_prio(struct sched_rt_entity *rt_se)
 {
 #ifdef CONFIG_RT_GROUP_SCHED
@@ -327,18 +447,10 @@ static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
         if (sched_rt_runtime(rt_rq) >= sched_rt_period(rt_rq))
                 return 0;
 
-#ifdef CONFIG_SMP
-        if (rt_rq->rt_time > runtime) {
-                int more;
-
-                spin_unlock(&rt_rq->rt_runtime_lock);
-                more = balance_runtime(rt_rq);
-                spin_lock(&rt_rq->rt_runtime_lock);
-
-                if (more)
-                        runtime = sched_rt_runtime(rt_rq);
-        }
-#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;
@@ -392,12 +504,23 @@ 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_RT_GROUP_SCHED
-        if (rt_se_prio(rt_se) < rt_rq->highest_prio)
+        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++;
         }
 
@@ -417,6 +540,10 @@ void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
 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--;
@@ -440,6 +567,14 @@ 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
@@ -455,6 +590,7 @@ 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);
 
         /*
          * Don't enqueue the group if its throttled, or when empty.
@@ -465,7 +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;
 
-        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);
@@ -532,6 +668,8 @@ static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup)
                 rt_se->timeout = 0;
 
         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)
@@ -540,36 +678,42 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep)
 
         update_curr_rt(rq);
         dequeue_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.
  */
-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;
-        struct list_head *queue = 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 (on_rt_rq(rt_se))
-                list_move_tail(&rt_se->run_list, queue);
+                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
@@ -609,6 +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 */
 
 /*
@@ -616,8 +784,27 @@ static int select_task_rq_rt(struct task_struct *p, int sync)
  */
 static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p)
 {
-        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,
@@ -720,73 +907,6 @@ 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;
@@ -808,17 +928,19 @@ 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
@@ -1006,7 +1128,7 @@ 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;
 
@@ -1163,17 +1285,25 @@ static void set_cpus_allowed_rt(struct task_struct *p,
 }
 
 /* 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);
 }
 
 /*
@@ -1306,7 +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);
         }
 }
@@ -1336,8 +1466,8 @@ static const struct sched_class rt_sched_class = {
         .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,
@@ -1350,3 +1480,17 @@ 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 */