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-rw-r--r--kernel/sched_rt.c455
1 files changed, 336 insertions, 119 deletions
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index fd10d96..1178257 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -45,47 +45,167 @@ static void update_rt_migration(struct rq *rq)
}
#endif /* CONFIG_SMP */
-static int sched_rt_ratio_exceeded(struct rq *rq, struct rt_rq *rt_rq)
+static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
{
+ return container_of(rt_se, struct task_struct, rt);
+}
+
+static inline int on_rt_rq(struct sched_rt_entity *rt_se)
+{
+ return !list_empty(&rt_se->run_list);
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+static inline unsigned int sched_rt_ratio(struct rt_rq *rt_rq)
+{
+ if (!rt_rq->tg)
+ return SCHED_RT_FRAC;
+
+ return rt_rq->tg->rt_ratio;
+}
+
+#define for_each_leaf_rt_rq(rt_rq, rq) \
+ list_for_each_entry(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)
+
+static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
+{
+ return rt_se->my_q;
+}
+
+static void enqueue_rt_entity(struct sched_rt_entity *rt_se);
+static void dequeue_rt_entity(struct sched_rt_entity *rt_se);
+
+static void sched_rt_ratio_enqueue(struct rt_rq *rt_rq)
+{
+ struct sched_rt_entity *rt_se = rt_rq->rt_se;
+
+ if (rt_se && !on_rt_rq(rt_se) && rt_rq->rt_nr_running) {
+ enqueue_rt_entity(rt_se);
+ resched_task(rq_of_rt_rq(rt_rq)->curr);
+ }
+}
+
+static void sched_rt_ratio_dequeue(struct rt_rq *rt_rq)
+{
+ struct sched_rt_entity *rt_se = rt_rq->rt_se;
+
+ if (rt_se && on_rt_rq(rt_se))
+ dequeue_rt_entity(rt_se);
+}
+
+#else
+
+static inline unsigned int sched_rt_ratio(struct rt_rq *rt_rq)
+{
+ return sysctl_sched_rt_ratio;
+}
+
+#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)
+
+static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
+{
+ return NULL;
+}
+
+static inline void sched_rt_ratio_enqueue(struct rt_rq *rt_rq)
+{
+}
+
+static inline void sched_rt_ratio_dequeue(struct rt_rq *rt_rq)
+{
+}
+
+#endif
+
+static inline int rt_se_prio(struct sched_rt_entity *rt_se)
+{
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ struct rt_rq *rt_rq = group_rt_rq(rt_se);
+
+ if (rt_rq)
+ return rt_rq->highest_prio;
+#endif
+
+ return rt_task_of(rt_se)->prio;
+}
+
+static int sched_rt_ratio_exceeded(struct rt_rq *rt_rq)
+{
+ unsigned int rt_ratio = sched_rt_ratio(rt_rq);
u64 period, ratio;
- if (sysctl_sched_rt_ratio == SCHED_RT_FRAC)
+ if (rt_ratio == SCHED_RT_FRAC)
return 0;
if (rt_rq->rt_throttled)
return 1;
period = (u64)sysctl_sched_rt_period * NSEC_PER_MSEC;
- ratio = (period * sysctl_sched_rt_ratio) >> SCHED_RT_FRAC_SHIFT;
+ ratio = (period * rt_ratio) >> SCHED_RT_FRAC_SHIFT;
if (rt_rq->rt_time > ratio) {
- rt_rq->rt_throttled = rq->clock + period - rt_rq->rt_time;
+ rt_rq->rt_throttled = 1;
+ sched_rt_ratio_dequeue(rt_rq);
return 1;
}
return 0;
}
+static void __update_sched_rt_period(struct rt_rq *rt_rq, u64 period)
+{
+ unsigned long rt_ratio = sched_rt_ratio(rt_rq);
+ u64 ratio = (period * rt_ratio) >> SCHED_RT_FRAC_SHIFT;
+
+ rt_rq->rt_time -= min(rt_rq->rt_time, ratio);
+ if (rt_rq->rt_throttled) {
+ rt_rq->rt_throttled = 0;
+ sched_rt_ratio_enqueue(rt_rq);
+ }
+}
+
static void update_sched_rt_period(struct rq *rq)
{
- while (rq->clock > rq->rt_period_expire) {
- u64 period, ratio;
+ struct rt_rq *rt_rq;
+ u64 period;
+ while (rq->clock > rq->rt_period_expire) {
period = (u64)sysctl_sched_rt_period * NSEC_PER_MSEC;
- ratio = (period * sysctl_sched_rt_ratio) >> SCHED_RT_FRAC_SHIFT;
-
- rq->rt.rt_time -= min(rq->rt.rt_time, ratio);
rq->rt_period_expire += period;
- }
- /*
- * When the rt throttle is expired, let them rip.
- * (XXX: use hrtick when available)
- */
- if (rq->rt.rt_throttled && rq->clock > rq->rt.rt_throttled) {
- rq->rt.rt_throttled = 0;
- if (!sched_rt_ratio_exceeded(rq, &rq->rt))
- resched_task(rq->curr);
+ for_each_leaf_rt_rq(rt_rq, rq)
+ __update_sched_rt_period(rt_rq, period);
}
}
@@ -96,6 +216,8 @@ static void update_sched_rt_period(struct rq *rq)
static void update_curr_rt(struct rq *rq)
{
struct task_struct *curr = rq->curr;
+ struct sched_rt_entity *rt_se = &curr->rt;
+ struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
u64 delta_exec;
if (!task_has_rt_policy(curr))
@@ -111,95 +233,184 @@ static void update_curr_rt(struct rq *rq)
curr->se.exec_start = rq->clock;
cpuacct_charge(curr, delta_exec);
- rq->rt.rt_time += delta_exec;
- update_sched_rt_period(rq);
- if (sched_rt_ratio_exceeded(rq, &rq->rt))
+ rt_rq->rt_time += delta_exec;
+ /*
+ * might make it a tad more accurate:
+ *
+ * update_sched_rt_period(rq);
+ */
+ if (sched_rt_ratio_exceeded(rt_rq))
resched_task(curr);
}
-static inline void inc_rt_tasks(struct task_struct *p, struct rq *rq)
+static inline
+void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
- WARN_ON(!rt_task(p));
- rq->rt.rt_nr_running++;
+ WARN_ON(!rt_prio(rt_se_prio(rt_se)));
+ rt_rq->rt_nr_running++;
+#if defined CONFIG_SMP || defined CONFIG_FAIR_GROUP_SCHED
+ if (rt_se_prio(rt_se) < rt_rq->highest_prio)
+ rt_rq->highest_prio = rt_se_prio(rt_se);
+#endif
#ifdef CONFIG_SMP
- if (p->prio < rq->rt.highest_prio)
- rq->rt.highest_prio = p->prio;
- if (p->nr_cpus_allowed > 1)
+ if (rt_se->nr_cpus_allowed > 1) {
+ struct rq *rq = rq_of_rt_rq(rt_rq);
rq->rt.rt_nr_migratory++;
+ }
- update_rt_migration(rq);
-#endif /* CONFIG_SMP */
+ update_rt_migration(rq_of_rt_rq(rt_rq));
+#endif
}
-static inline void dec_rt_tasks(struct task_struct *p, struct rq *rq)
+static inline
+void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
- WARN_ON(!rt_task(p));
- WARN_ON(!rq->rt.rt_nr_running);
- rq->rt.rt_nr_running--;
-#ifdef CONFIG_SMP
- if (rq->rt.rt_nr_running) {
+ 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_FAIR_GROUP_SCHED
+ if (rt_rq->rt_nr_running) {
struct rt_prio_array *array;
- WARN_ON(p->prio < rq->rt.highest_prio);
- if (p->prio == rq->rt.highest_prio) {
+ WARN_ON(rt_se_prio(rt_se) < rt_rq->highest_prio);
+ if (rt_se_prio(rt_se) == rt_rq->highest_prio) {
/* recalculate */
- array = &rq->rt.active;
- rq->rt.highest_prio =
+ array = &rt_rq->active;
+ rt_rq->highest_prio =
sched_find_first_bit(array->bitmap);
} /* otherwise leave rq->highest prio alone */
} else
- rq->rt.highest_prio = MAX_RT_PRIO;
- if (p->nr_cpus_allowed > 1)
+ 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--;
+ }
- update_rt_migration(rq);
+ update_rt_migration(rq_of_rt_rq(rt_rq));
#endif /* CONFIG_SMP */
}
-static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup)
+static void enqueue_rt_entity(struct sched_rt_entity *rt_se)
{
- struct rt_prio_array *array = &rq->rt.active;
+ 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);
- list_add_tail(&p->rt.run_list, array->queue + p->prio);
- __set_bit(p->prio, array->bitmap);
- inc_cpu_load(rq, p->se.load.weight);
+ if (group_rq && group_rq->rt_throttled)
+ return;
- inc_rt_tasks(p, rq);
+ list_add_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se));
+ __set_bit(rt_se_prio(rt_se), array->bitmap);
- if (wakeup)
- p->rt.timeout = 0;
+ inc_rt_tasks(rt_se, rt_rq);
+}
+
+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->queue + rt_se_prio(rt_se)))
+ __clear_bit(rt_se_prio(rt_se), array->bitmap);
+
+ dec_rt_tasks(rt_se, rt_rq);
+}
+
+/*
+ * Because the prio of an upper entry depends on the lower
+ * entries, we must remove entries top - down.
+ *
+ * XXX: O(1/2 h^2) because we can only walk up, not down the chain.
+ * doesn't matter much for now, as h=2 for GROUP_SCHED.
+ */
+static void dequeue_rt_stack(struct task_struct *p)
+{
+ struct sched_rt_entity *rt_se, *top_se;
+
+ /*
+ * dequeue all, top - down.
+ */
+ do {
+ rt_se = &p->rt;
+ top_se = NULL;
+ for_each_sched_rt_entity(rt_se) {
+ if (on_rt_rq(rt_se))
+ top_se = rt_se;
+ }
+ if (top_se)
+ dequeue_rt_entity(top_se);
+ } while (top_se);
}
/*
* Adding/removing a task to/from a priority array:
*/
+static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup)
+{
+ struct sched_rt_entity *rt_se = &p->rt;
+
+ if (wakeup)
+ rt_se->timeout = 0;
+
+ dequeue_rt_stack(p);
+
+ /*
+ * 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 rt_prio_array *array = &rq->rt.active;
+ struct sched_rt_entity *rt_se = &p->rt;
+ struct rt_rq *rt_rq;
update_curr_rt(rq);
- list_del(&p->rt.run_list);
- if (list_empty(array->queue + p->prio))
- __clear_bit(p->prio, array->bitmap);
- dec_cpu_load(rq, p->se.load.weight);
+ 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_rt_tasks(p, rq);
+ 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)
+{
+ struct rt_prio_array *array = &rt_rq->active;
+
+ list_move_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se));
+}
+
static void requeue_task_rt(struct rq *rq, struct task_struct *p)
{
- struct rt_prio_array *array = &rq->rt.active;
+ struct sched_rt_entity *rt_se = &p->rt;
+ struct rt_rq *rt_rq;
- list_move_tail(&p->rt.run_list, array->queue + p->prio);
+ for_each_sched_rt_entity(rt_se) {
+ rt_rq = rt_rq_of_se(rt_se);
+ requeue_rt_entity(rt_rq, rt_se);
+ }
}
-static void
-yield_task_rt(struct rq *rq)
+static void yield_task_rt(struct rq *rq)
{
requeue_task_rt(rq, rq->curr);
}
@@ -229,7 +440,7 @@ static int select_task_rq_rt(struct task_struct *p, int sync)
* cold cache anyway.
*/
if (unlikely(rt_task(rq->curr)) &&
- (p->nr_cpus_allowed > 1)) {
+ (p->rt.nr_cpus_allowed > 1)) {
int cpu = find_lowest_rq(p);
return (cpu == -1) ? task_cpu(p) : cpu;
@@ -252,27 +463,51 @@ static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p)
resched_task(rq->curr);
}
-static struct task_struct *pick_next_task_rt(struct rq *rq)
+static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
+ struct rt_rq *rt_rq)
{
- struct rt_prio_array *array = &rq->rt.active;
- struct task_struct *next;
+ struct rt_prio_array *array = &rt_rq->active;
+ struct sched_rt_entity *next = NULL;
struct list_head *queue;
- struct rt_rq *rt_rq = &rq->rt;
int idx;
- if (sched_rt_ratio_exceeded(rq, rt_rq))
- return NULL;
+ if (sched_rt_ratio_exceeded(rt_rq))
+ goto out;
idx = sched_find_first_bit(array->bitmap);
- if (idx >= MAX_RT_PRIO)
- return NULL;
+ BUG_ON(idx >= MAX_RT_PRIO);
queue = array->queue + idx;
- next = list_entry(queue->next, struct task_struct, rt.run_list);
+ next = list_entry(queue->next, struct sched_rt_entity, run_list);
+ out:
+ return next;
+}
- next->se.exec_start = rq->clock;
+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;
- return next;
+ retry:
+ rt_rq = &rq->rt;
+
+ if (unlikely(!rt_rq->rt_nr_running))
+ return NULL;
+
+ if (sched_rt_ratio_exceeded(rt_rq))
+ return NULL;
+
+ do {
+ rt_se = pick_next_rt_entity(rq, rt_rq);
+ if (unlikely(!rt_se))
+ goto retry;
+ rt_rq = group_rt_rq(rt_se);
+ } while (rt_rq);
+
+ p = rt_task_of(rt_se);
+ p->se.exec_start = rq->clock;
+ return p;
}
static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
@@ -282,6 +517,7 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
}
#ifdef CONFIG_SMP
+
/* Only try algorithms three times */
#define RT_MAX_TRIES 3
@@ -292,7 +528,7 @@ static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
{
if (!task_running(rq, p) &&
(cpu < 0 || cpu_isset(cpu, p->cpus_allowed)) &&
- (p->nr_cpus_allowed > 1))
+ (p->rt.nr_cpus_allowed > 1))
return 1;
return 0;
}
@@ -300,52 +536,33 @@ static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
/* Return the second highest RT task, NULL otherwise */
static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu)
{
- struct rt_prio_array *array = &rq->rt.active;
- struct task_struct *next;
- struct list_head *queue;
+ struct task_struct *next = NULL;
+ struct sched_rt_entity *rt_se;
+ struct rt_prio_array *array;
+ struct rt_rq *rt_rq;
int idx;
- if (likely(rq->rt.rt_nr_running < 2))
- return NULL;
-
- idx = sched_find_first_bit(array->bitmap);
- if (unlikely(idx >= MAX_RT_PRIO)) {
- WARN_ON(1); /* rt_nr_running is bad */
- return NULL;
- }
-
- queue = array->queue + idx;
- BUG_ON(list_empty(queue));
-
- next = list_entry(queue->next, struct task_struct, rt.run_list);
- if (unlikely(pick_rt_task(rq, next, cpu)))
- goto out;
-
- if (queue->next->next != queue) {
- /* same prio task */
- next = list_entry(queue->next->next, struct task_struct,
- rt.run_list);
- if (pick_rt_task(rq, next, cpu))
- goto out;
- }
-
- retry:
- /* slower, but more flexible */
- idx = find_next_bit(array->bitmap, MAX_RT_PRIO, idx+1);
- if (unlikely(idx >= MAX_RT_PRIO))
- return NULL;
-
- queue = array->queue + idx;
- BUG_ON(list_empty(queue));
-
- list_for_each_entry(next, queue, rt.run_list) {
- if (pick_rt_task(rq, next, cpu))
- goto out;
+ for_each_leaf_rt_rq(rt_rq, rq) {
+ array = &rt_rq->active;
+ idx = sched_find_first_bit(array->bitmap);
+ next_idx:
+ if (idx >= MAX_RT_PRIO)
+ continue;
+ if (next && next->prio < idx)
+ continue;
+ 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;
+ break;
+ }
+ }
+ if (!next) {
+ idx = find_next_bit(array->bitmap, MAX_RT_PRIO, idx+1);
+ goto next_idx;
+ }
}
- goto retry;
-
- out:
return next;
}
@@ -774,12 +991,12 @@ static void set_cpus_allowed_rt(struct task_struct *p, cpumask_t *new_mask)
* Update the migration status of the RQ if we have an RT task
* which is running AND changing its weight value.
*/
- if (p->se.on_rq && (weight != p->nr_cpus_allowed)) {
+ if (p->se.on_rq && (weight != p->rt.nr_cpus_allowed)) {
struct rq *rq = task_rq(p);
- if ((p->nr_cpus_allowed <= 1) && (weight > 1)) {
+ if ((p->rt.nr_cpus_allowed <= 1) && (weight > 1)) {
rq->rt.rt_nr_migratory++;
- } else if ((p->nr_cpus_allowed > 1) && (weight <= 1)) {
+ } else if ((p->rt.nr_cpus_allowed > 1) && (weight <= 1)) {
BUG_ON(!rq->rt.rt_nr_migratory);
rq->rt.rt_nr_migratory--;
}
@@ -788,7 +1005,7 @@ static void set_cpus_allowed_rt(struct task_struct *p, cpumask_t *new_mask)
}
p->cpus_allowed = *new_mask;
- p->nr_cpus_allowed = weight;
+ p->rt.nr_cpus_allowed = weight;
}
/* Assumes rq->lock is held */
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