rt.c 46.1 KB
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/*
 * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR
 * policies)
 */

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#include "sched.h"

#include <linux/slab.h>

static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);

struct rt_bandwidth def_rt_bandwidth;

static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
{
	struct rt_bandwidth *rt_b =
		container_of(timer, struct rt_bandwidth, rt_period_timer);
	ktime_t now;
	int overrun;
	int idle = 0;

	for (;;) {
		now = hrtimer_cb_get_time(timer);
		overrun = hrtimer_forward(timer, now, rt_b->rt_period);

		if (!overrun)
			break;

		idle = do_sched_rt_period_timer(rt_b, overrun);
	}

	return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
}

void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
{
	rt_b->rt_period = ns_to_ktime(period);
	rt_b->rt_runtime = runtime;

	raw_spin_lock_init(&rt_b->rt_runtime_lock);

	hrtimer_init(&rt_b->rt_period_timer,
			CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	rt_b->rt_period_timer.function = sched_rt_period_timer;
}

static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
{
	if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
		return;

	if (hrtimer_active(&rt_b->rt_period_timer))
		return;

	raw_spin_lock(&rt_b->rt_runtime_lock);
	start_bandwidth_timer(&rt_b->rt_period_timer, rt_b->rt_period);
	raw_spin_unlock(&rt_b->rt_runtime_lock);
}

void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
{
	struct rt_prio_array *array;
	int i;

	array = &rt_rq->active;
	for (i = 0; i < MAX_RT_PRIO; i++) {
		INIT_LIST_HEAD(array->queue + i);
		__clear_bit(i, array->bitmap);
	}
	/* delimiter for bitsearch: */
	__set_bit(MAX_RT_PRIO, array->bitmap);

#if defined CONFIG_SMP
	rt_rq->highest_prio.curr = MAX_RT_PRIO;
	rt_rq->highest_prio.next = MAX_RT_PRIO;
	rt_rq->rt_nr_migratory = 0;
	rt_rq->overloaded = 0;
	plist_head_init(&rt_rq->pushable_tasks);
#endif

	rt_rq->rt_time = 0;
	rt_rq->rt_throttled = 0;
	rt_rq->rt_runtime = 0;
	raw_spin_lock_init(&rt_rq->rt_runtime_lock);
}

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#ifdef CONFIG_RT_GROUP_SCHED
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static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
{
	hrtimer_cancel(&rt_b->rt_period_timer);
}
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#define rt_entity_is_task(rt_se) (!(rt_se)->my_q)

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static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
{
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#ifdef CONFIG_SCHED_DEBUG
	WARN_ON_ONCE(!rt_entity_is_task(rt_se));
#endif
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	return container_of(rt_se, struct task_struct, rt);
}

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;
}

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void free_rt_sched_group(struct task_group *tg)
{
	int i;

	if (tg->rt_se)
		destroy_rt_bandwidth(&tg->rt_bandwidth);

	for_each_possible_cpu(i) {
		if (tg->rt_rq)
			kfree(tg->rt_rq[i]);
		if (tg->rt_se)
			kfree(tg->rt_se[i]);
	}

	kfree(tg->rt_rq);
	kfree(tg->rt_se);
}

void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
		struct sched_rt_entity *rt_se, int cpu,
		struct sched_rt_entity *parent)
{
	struct rq *rq = cpu_rq(cpu);

	rt_rq->highest_prio.curr = MAX_RT_PRIO;
	rt_rq->rt_nr_boosted = 0;
	rt_rq->rq = rq;
	rt_rq->tg = tg;

	tg->rt_rq[cpu] = rt_rq;
	tg->rt_se[cpu] = rt_se;

	if (!rt_se)
		return;

	if (!parent)
		rt_se->rt_rq = &rq->rt;
	else
		rt_se->rt_rq = parent->my_q;

	rt_se->my_q = rt_rq;
	rt_se->parent = parent;
	INIT_LIST_HEAD(&rt_se->run_list);
}

int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
{
	struct rt_rq *rt_rq;
	struct sched_rt_entity *rt_se;
	int i;

	tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
	if (!tg->rt_rq)
		goto err;
	tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
	if (!tg->rt_se)
		goto err;

	init_rt_bandwidth(&tg->rt_bandwidth,
			ktime_to_ns(def_rt_bandwidth.rt_period), 0);

	for_each_possible_cpu(i) {
		rt_rq = kzalloc_node(sizeof(struct rt_rq),
				     GFP_KERNEL, cpu_to_node(i));
		if (!rt_rq)
			goto err;

		rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
				     GFP_KERNEL, cpu_to_node(i));
		if (!rt_se)
			goto err_free_rq;

		init_rt_rq(rt_rq, cpu_rq(i));
		rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
		init_tg_rt_entry(tg, rt_rq, rt_se, i, parent->rt_se[i]);
	}

	return 1;

err_free_rq:
	kfree(rt_rq);
err:
	return 0;
}

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#else /* CONFIG_RT_GROUP_SCHED */

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#define rt_entity_is_task(rt_se) (1)

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static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
{
	return container_of(rt_se, struct task_struct, rt);
}

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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;
}

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void free_rt_sched_group(struct task_group *tg) { }

int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
{
	return 1;
}
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#endif /* CONFIG_RT_GROUP_SCHED */

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#ifdef CONFIG_SMP
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static inline int rt_overloaded(struct rq *rq)
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{
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	return atomic_read(&rq->rd->rto_count);
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}
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static inline void rt_set_overload(struct rq *rq)
{
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	if (!rq->online)
		return;

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	cpumask_set_cpu(rq->cpu, rq->rd->rto_mask);
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	/*
	 * Make sure the mask is visible before we set
	 * the overload count. That is checked to determine
	 * if we should look at the mask. It would be a shame
	 * if we looked at the mask, but the mask was not
	 * updated yet.
	 */
	wmb();
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	atomic_inc(&rq->rd->rto_count);
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}
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static inline void rt_clear_overload(struct rq *rq)
{
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	if (!rq->online)
		return;

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	/* the order here really doesn't matter */
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	atomic_dec(&rq->rd->rto_count);
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	cpumask_clear_cpu(rq->cpu, rq->rd->rto_mask);
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}
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static void update_rt_migration(struct rt_rq *rt_rq)
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{
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	if (rt_rq->rt_nr_migratory && rt_rq->rt_nr_total > 1) {
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		if (!rt_rq->overloaded) {
			rt_set_overload(rq_of_rt_rq(rt_rq));
			rt_rq->overloaded = 1;
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		}
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	} else if (rt_rq->overloaded) {
		rt_clear_overload(rq_of_rt_rq(rt_rq));
		rt_rq->overloaded = 0;
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	}
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}
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static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
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	if (!rt_entity_is_task(rt_se))
		return;

	rt_rq = &rq_of_rt_rq(rt_rq)->rt;

	rt_rq->rt_nr_total++;
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	if (rt_se->nr_cpus_allowed > 1)
		rt_rq->rt_nr_migratory++;

	update_rt_migration(rt_rq);
}

static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
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	if (!rt_entity_is_task(rt_se))
		return;

	rt_rq = &rq_of_rt_rq(rt_rq)->rt;

	rt_rq->rt_nr_total--;
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	if (rt_se->nr_cpus_allowed > 1)
		rt_rq->rt_nr_migratory--;

	update_rt_migration(rt_rq);
}

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static inline int has_pushable_tasks(struct rq *rq)
{
	return !plist_head_empty(&rq->rt.pushable_tasks);
}

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static void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
{
	plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
	plist_node_init(&p->pushable_tasks, p->prio);
	plist_add(&p->pushable_tasks, &rq->rt.pushable_tasks);
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	/* Update the highest prio pushable task */
	if (p->prio < rq->rt.highest_prio.next)
		rq->rt.highest_prio.next = p->prio;
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}

static void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
{
	plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);

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	/* Update the new highest prio pushable task */
	if (has_pushable_tasks(rq)) {
		p = plist_first_entry(&rq->rt.pushable_tasks,
				      struct task_struct, pushable_tasks);
		rq->rt.highest_prio.next = p->prio;
	} else
		rq->rt.highest_prio.next = MAX_RT_PRIO;
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}

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#else

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static inline void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
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{
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}

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static inline void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
{
}

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static inline
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void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
}

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static inline
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void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
}
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#endif /* CONFIG_SMP */

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static inline int on_rt_rq(struct sched_rt_entity *rt_se)
{
	return !list_empty(&rt_se->run_list);
}

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#ifdef CONFIG_RT_GROUP_SCHED
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static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
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{
	if (!rt_rq->tg)
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		return RUNTIME_INF;
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	return rt_rq->rt_runtime;
}

static inline u64 sched_rt_period(struct rt_rq *rt_rq)
{
	return ktime_to_ns(rt_rq->tg->rt_bandwidth.rt_period);
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}

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typedef struct task_group *rt_rq_iter_t;

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static inline struct task_group *next_task_group(struct task_group *tg)
{
	do {
		tg = list_entry_rcu(tg->list.next,
			typeof(struct task_group), list);
	} while (&tg->list != &task_groups && task_group_is_autogroup(tg));

	if (&tg->list == &task_groups)
		tg = NULL;

	return tg;
}

#define for_each_rt_rq(rt_rq, iter, rq)					\
	for (iter = container_of(&task_groups, typeof(*iter), list);	\
		(iter = next_task_group(iter)) &&			\
		(rt_rq = iter->rt_rq[cpu_of(rq)]);)
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static inline void list_add_leaf_rt_rq(struct rt_rq *rt_rq)
{
	list_add_rcu(&rt_rq->leaf_rt_rq_list,
			&rq_of_rt_rq(rt_rq)->leaf_rt_rq_list);
}

static inline void list_del_leaf_rt_rq(struct rt_rq *rt_rq)
{
	list_del_rcu(&rt_rq->leaf_rt_rq_list);
}

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#define for_each_leaf_rt_rq(rt_rq, rq) \
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	list_for_each_entry_rcu(rt_rq, &rq->leaf_rt_rq_list, leaf_rt_rq_list)
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#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;
}

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static void enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head);
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static void dequeue_rt_entity(struct sched_rt_entity *rt_se);

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static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
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{
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	struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
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	struct sched_rt_entity *rt_se;

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	int cpu = cpu_of(rq_of_rt_rq(rt_rq));

	rt_se = rt_rq->tg->rt_se[cpu];
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	if (rt_rq->rt_nr_running) {
		if (rt_se && !on_rt_rq(rt_se))
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			enqueue_rt_entity(rt_se, false);
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		if (rt_rq->highest_prio.curr < curr->prio)
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			resched_task(curr);
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	}
}

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static void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
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{
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	struct sched_rt_entity *rt_se;
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	int cpu = cpu_of(rq_of_rt_rq(rt_rq));
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	rt_se = rt_rq->tg->rt_se[cpu];
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	if (rt_se && on_rt_rq(rt_se))
		dequeue_rt_entity(rt_se);
}

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static inline int rt_rq_throttled(struct rt_rq *rt_rq)
{
	return rt_rq->rt_throttled && !rt_rq->rt_nr_boosted;
}

static int rt_se_boosted(struct sched_rt_entity *rt_se)
{
	struct rt_rq *rt_rq = group_rt_rq(rt_se);
	struct task_struct *p;

	if (rt_rq)
		return !!rt_rq->rt_nr_boosted;

	p = rt_task_of(rt_se);
	return p->prio != p->normal_prio;
}

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#ifdef CONFIG_SMP
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static inline const struct cpumask *sched_rt_period_mask(void)
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{
	return cpu_rq(smp_processor_id())->rd->span;
}
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#else
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static inline const struct cpumask *sched_rt_period_mask(void)
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{
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	return cpu_online_mask;
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}
#endif
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static inline
struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
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{
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	return container_of(rt_b, struct task_group, rt_bandwidth)->rt_rq[cpu];
}
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static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
{
	return &rt_rq->tg->rt_bandwidth;
}

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#else /* !CONFIG_RT_GROUP_SCHED */
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static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
{
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	return rt_rq->rt_runtime;
}

static inline u64 sched_rt_period(struct rt_rq *rt_rq)
{
	return ktime_to_ns(def_rt_bandwidth.rt_period);
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}

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typedef struct rt_rq *rt_rq_iter_t;

#define for_each_rt_rq(rt_rq, iter, rq) \
	for ((void) iter, rt_rq = &rq->rt; rt_rq; rt_rq = NULL)

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static inline void list_add_leaf_rt_rq(struct rt_rq *rt_rq)
{
}

static inline void list_del_leaf_rt_rq(struct rt_rq *rt_rq)
{
}

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#define for_each_leaf_rt_rq(rt_rq, rq) \
	for (rt_rq = &rq->rt; rt_rq; rt_rq = NULL)

#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;
}

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static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
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{
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	if (rt_rq->rt_nr_running)
		resched_task(rq_of_rt_rq(rt_rq)->curr);
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}

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static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
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{
}

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static inline int rt_rq_throttled(struct rt_rq *rt_rq)
{
	return rt_rq->rt_throttled;
}
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static inline const struct cpumask *sched_rt_period_mask(void)
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{
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	return cpu_online_mask;
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}

static inline
struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
{
	return &cpu_rq(cpu)->rt;
}

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static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
{
	return &def_rt_bandwidth;
}

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#endif /* CONFIG_RT_GROUP_SCHED */
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#ifdef CONFIG_SMP
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/*
 * We ran out of runtime, see if we can borrow some from our neighbours.
 */
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static int do_balance_runtime(struct rt_rq *rt_rq)
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{
	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;

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	weight = cpumask_weight(rd->span);
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	raw_spin_lock(&rt_b->rt_runtime_lock);
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	rt_period = ktime_to_ns(rt_b->rt_period);
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	for_each_cpu(i, rd->span) {
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		struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
		s64 diff;

		if (iter == rt_rq)
			continue;

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		raw_spin_lock(&iter->rt_runtime_lock);
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		/*
		 * Either all rqs have inf runtime and there's nothing to steal
		 * or __disable_runtime() below sets a specific rq to inf to
		 * indicate its been disabled and disalow stealing.
		 */
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		if (iter->rt_runtime == RUNTIME_INF)
			goto next;

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		/*
		 * From runqueues with spare time, take 1/n part of their
		 * spare time, but no more than our period.
		 */
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		diff = iter->rt_runtime - iter->rt_time;
		if (diff > 0) {
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			diff = div_u64((u64)diff, weight);
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			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) {
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				raw_spin_unlock(&iter->rt_runtime_lock);
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				break;
			}
		}
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next:
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		raw_spin_unlock(&iter->rt_runtime_lock);
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	}
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	raw_spin_unlock(&rt_b->rt_runtime_lock);
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	return more;
}
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/*
 * Ensure this RQ takes back all the runtime it lend to its neighbours.
 */
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Peter Zijlstra 已提交
615 616 617
static void __disable_runtime(struct rq *rq)
{
	struct root_domain *rd = rq->rd;
C
Cheng Xu 已提交
618
	rt_rq_iter_t iter;
P
Peter Zijlstra 已提交
619 620 621 622 623
	struct rt_rq *rt_rq;

	if (unlikely(!scheduler_running))
		return;

C
Cheng Xu 已提交
624
	for_each_rt_rq(rt_rq, iter, rq) {
P
Peter Zijlstra 已提交
625 626 627 628
		struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
		s64 want;
		int i;

629 630
		raw_spin_lock(&rt_b->rt_runtime_lock);
		raw_spin_lock(&rt_rq->rt_runtime_lock);
631 632 633 634 635
		/*
		 * Either we're all inf and nobody needs to borrow, or we're
		 * already disabled and thus have nothing to do, or we have
		 * exactly the right amount of runtime to take out.
		 */
P
Peter Zijlstra 已提交
636 637 638
		if (rt_rq->rt_runtime == RUNTIME_INF ||
				rt_rq->rt_runtime == rt_b->rt_runtime)
			goto balanced;
639
		raw_spin_unlock(&rt_rq->rt_runtime_lock);
P
Peter Zijlstra 已提交
640

641 642 643 644 645
		/*
		 * Calculate the difference between what we started out with
		 * and what we current have, that's the amount of runtime
		 * we lend and now have to reclaim.
		 */
P
Peter Zijlstra 已提交
646 647
		want = rt_b->rt_runtime - rt_rq->rt_runtime;

648 649 650
		/*
		 * Greedy reclaim, take back as much as we can.
		 */
651
		for_each_cpu(i, rd->span) {
P
Peter Zijlstra 已提交
652 653 654
			struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
			s64 diff;

655 656 657
			/*
			 * Can't reclaim from ourselves or disabled runqueues.
			 */
658
			if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
P
Peter Zijlstra 已提交
659 660
				continue;

661
			raw_spin_lock(&iter->rt_runtime_lock);
P
Peter Zijlstra 已提交
662 663 664 665 666 667 668 669
			if (want > 0) {
				diff = min_t(s64, iter->rt_runtime, want);
				iter->rt_runtime -= diff;
				want -= diff;
			} else {
				iter->rt_runtime -= want;
				want -= want;
			}
670
			raw_spin_unlock(&iter->rt_runtime_lock);
P
Peter Zijlstra 已提交
671 672 673 674 675

			if (!want)
				break;
		}

676
		raw_spin_lock(&rt_rq->rt_runtime_lock);
677 678 679 680
		/*
		 * We cannot be left wanting - that would mean some runtime
		 * leaked out of the system.
		 */
P
Peter Zijlstra 已提交
681 682
		BUG_ON(want);
balanced:
683 684 685 686
		/*
		 * Disable all the borrow logic by pretending we have inf
		 * runtime - in which case borrowing doesn't make sense.
		 */
P
Peter Zijlstra 已提交
687
		rt_rq->rt_runtime = RUNTIME_INF;
688 689
		raw_spin_unlock(&rt_rq->rt_runtime_lock);
		raw_spin_unlock(&rt_b->rt_runtime_lock);
P
Peter Zijlstra 已提交
690 691 692 693 694 695 696
	}
}

static void disable_runtime(struct rq *rq)
{
	unsigned long flags;

697
	raw_spin_lock_irqsave(&rq->lock, flags);
P
Peter Zijlstra 已提交
698
	__disable_runtime(rq);
699
	raw_spin_unlock_irqrestore(&rq->lock, flags);
P
Peter Zijlstra 已提交
700 701 702 703
}

static void __enable_runtime(struct rq *rq)
{
C
Cheng Xu 已提交
704
	rt_rq_iter_t iter;
P
Peter Zijlstra 已提交
705 706 707 708 709
	struct rt_rq *rt_rq;

	if (unlikely(!scheduler_running))
		return;

710 711 712
	/*
	 * Reset each runqueue's bandwidth settings
	 */
C
Cheng Xu 已提交
713
	for_each_rt_rq(rt_rq, iter, rq) {
P
Peter Zijlstra 已提交
714 715
		struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);

716 717
		raw_spin_lock(&rt_b->rt_runtime_lock);
		raw_spin_lock(&rt_rq->rt_runtime_lock);
P
Peter Zijlstra 已提交
718 719
		rt_rq->rt_runtime = rt_b->rt_runtime;
		rt_rq->rt_time = 0;
720
		rt_rq->rt_throttled = 0;
721 722
		raw_spin_unlock(&rt_rq->rt_runtime_lock);
		raw_spin_unlock(&rt_b->rt_runtime_lock);
P
Peter Zijlstra 已提交
723 724 725 726 727 728 729
	}
}

static void enable_runtime(struct rq *rq)
{
	unsigned long flags;

730
	raw_spin_lock_irqsave(&rq->lock, flags);
P
Peter Zijlstra 已提交
731
	__enable_runtime(rq);
732
	raw_spin_unlock_irqrestore(&rq->lock, flags);
P
Peter Zijlstra 已提交
733 734
}

735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756
int update_runtime(struct notifier_block *nfb, unsigned long action, void *hcpu)
{
	int cpu = (int)(long)hcpu;

	switch (action) {
	case CPU_DOWN_PREPARE:
	case CPU_DOWN_PREPARE_FROZEN:
		disable_runtime(cpu_rq(cpu));
		return NOTIFY_OK;

	case CPU_DOWN_FAILED:
	case CPU_DOWN_FAILED_FROZEN:
	case CPU_ONLINE:
	case CPU_ONLINE_FROZEN:
		enable_runtime(cpu_rq(cpu));
		return NOTIFY_OK;

	default:
		return NOTIFY_DONE;
	}
}

757 758 759 760
static int balance_runtime(struct rt_rq *rt_rq)
{
	int more = 0;

761 762 763
	if (!sched_feat(RT_RUNTIME_SHARE))
		return more;

764
	if (rt_rq->rt_time > rt_rq->rt_runtime) {
765
		raw_spin_unlock(&rt_rq->rt_runtime_lock);
766
		more = do_balance_runtime(rt_rq);
767
		raw_spin_lock(&rt_rq->rt_runtime_lock);
768 769 770 771
	}

	return more;
}
772
#else /* !CONFIG_SMP */
773 774 775 776
static inline int balance_runtime(struct rt_rq *rt_rq)
{
	return 0;
}
777
#endif /* CONFIG_SMP */
P
Peter Zijlstra 已提交
778

779 780 781
static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
{
	int i, idle = 1;
782
	const struct cpumask *span;
783

784
	if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
785 786 787
		return 1;

	span = sched_rt_period_mask();
788
	for_each_cpu(i, span) {
789 790 791 792
		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);

793
		raw_spin_lock(&rq->lock);
794 795 796
		if (rt_rq->rt_time) {
			u64 runtime;

797
			raw_spin_lock(&rt_rq->rt_runtime_lock);
798 799 800 801 802 803 804
			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;
805 806 807 808 809 810 811

				/*
				 * Force a clock update if the CPU was idle,
				 * lest wakeup -> unthrottle time accumulate.
				 */
				if (rt_rq->rt_nr_running && rq->curr == rq->idle)
					rq->skip_clock_update = -1;
812 813 814
			}
			if (rt_rq->rt_time || rt_rq->rt_nr_running)
				idle = 0;
815
			raw_spin_unlock(&rt_rq->rt_runtime_lock);
816
		} else if (rt_rq->rt_nr_running) {
817
			idle = 0;
818 819 820
			if (!rt_rq_throttled(rt_rq))
				enqueue = 1;
		}
821 822 823

		if (enqueue)
			sched_rt_rq_enqueue(rt_rq);
824
		raw_spin_unlock(&rq->lock);
825 826 827 828
	}

	return idle;
}
P
Peter Zijlstra 已提交
829

P
Peter Zijlstra 已提交
830 831
static inline int rt_se_prio(struct sched_rt_entity *rt_se)
{
832
#ifdef CONFIG_RT_GROUP_SCHED
P
Peter Zijlstra 已提交
833 834 835
	struct rt_rq *rt_rq = group_rt_rq(rt_se);

	if (rt_rq)
836
		return rt_rq->highest_prio.curr;
P
Peter Zijlstra 已提交
837 838 839 840 841
#endif

	return rt_task_of(rt_se)->prio;
}

P
Peter Zijlstra 已提交
842
static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
P
Peter Zijlstra 已提交
843
{
P
Peter Zijlstra 已提交
844
	u64 runtime = sched_rt_runtime(rt_rq);
P
Peter Zijlstra 已提交
845 846

	if (rt_rq->rt_throttled)
P
Peter Zijlstra 已提交
847
		return rt_rq_throttled(rt_rq);
P
Peter Zijlstra 已提交
848

849
	if (runtime >= sched_rt_period(rt_rq))
P
Peter Zijlstra 已提交
850 851
		return 0;

852 853 854 855
	balance_runtime(rt_rq);
	runtime = sched_rt_runtime(rt_rq);
	if (runtime == RUNTIME_INF)
		return 0;
P
Peter Zijlstra 已提交
856

P
Peter Zijlstra 已提交
857
	if (rt_rq->rt_time > runtime) {
P
Peter Zijlstra 已提交
858
		rt_rq->rt_throttled = 1;
T
Thomas Gleixner 已提交
859
		printk_once(KERN_WARNING "sched: RT throttling activated\n");
P
Peter Zijlstra 已提交
860
		if (rt_rq_throttled(rt_rq)) {
P
Peter Zijlstra 已提交
861
			sched_rt_rq_dequeue(rt_rq);
P
Peter Zijlstra 已提交
862 863
			return 1;
		}
P
Peter Zijlstra 已提交
864 865 866 867 868
	}

	return 0;
}

I
Ingo Molnar 已提交
869 870 871 872
/*
 * Update the current task's runtime statistics. Skip current tasks that
 * are not in our scheduling class.
 */
A
Alexey Dobriyan 已提交
873
static void update_curr_rt(struct rq *rq)
I
Ingo Molnar 已提交
874 875
{
	struct task_struct *curr = rq->curr;
P
Peter Zijlstra 已提交
876 877
	struct sched_rt_entity *rt_se = &curr->rt;
	struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
I
Ingo Molnar 已提交
878 879
	u64 delta_exec;

P
Peter Zijlstra 已提交
880
	if (curr->sched_class != &rt_sched_class)
I
Ingo Molnar 已提交
881 882
		return;

883
	delta_exec = rq->clock_task - curr->se.exec_start;
I
Ingo Molnar 已提交
884 885
	if (unlikely((s64)delta_exec < 0))
		delta_exec = 0;
I
Ingo Molnar 已提交
886

887
	schedstat_set(curr->se.statistics.exec_max, max(curr->se.statistics.exec_max, delta_exec));
I
Ingo Molnar 已提交
888 889

	curr->se.sum_exec_runtime += delta_exec;
890 891
	account_group_exec_runtime(curr, delta_exec);

892
	curr->se.exec_start = rq->clock_task;
893
	cpuacct_charge(curr, delta_exec);
P
Peter Zijlstra 已提交
894

895 896
	sched_rt_avg_update(rq, delta_exec);

897 898 899
	if (!rt_bandwidth_enabled())
		return;

D
Dhaval Giani 已提交
900 901 902
	for_each_sched_rt_entity(rt_se) {
		rt_rq = rt_rq_of_se(rt_se);

903
		if (sched_rt_runtime(rt_rq) != RUNTIME_INF) {
904
			raw_spin_lock(&rt_rq->rt_runtime_lock);
905 906 907
			rt_rq->rt_time += delta_exec;
			if (sched_rt_runtime_exceeded(rt_rq))
				resched_task(curr);
908
			raw_spin_unlock(&rt_rq->rt_runtime_lock);
909
		}
D
Dhaval Giani 已提交
910
	}
I
Ingo Molnar 已提交
911 912
}

913
#if defined CONFIG_SMP
914

915 916
static void
inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
917
{
G
Gregory Haskins 已提交
918
	struct rq *rq = rq_of_rt_rq(rt_rq);
919

920 921
	if (rq->online && prio < prev_prio)
		cpupri_set(&rq->rd->cpupri, rq->cpu, prio);
922
}
923

924 925 926 927
static void
dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
{
	struct rq *rq = rq_of_rt_rq(rt_rq);
928

929 930
	if (rq->online && rt_rq->highest_prio.curr != prev_prio)
		cpupri_set(&rq->rd->cpupri, rq->cpu, rt_rq->highest_prio.curr);
931 932
}

933 934
#else /* CONFIG_SMP */

P
Peter Zijlstra 已提交
935
static inline
936 937 938 939 940
void inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
static inline
void dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}

#endif /* CONFIG_SMP */
941

942
#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958
static void
inc_rt_prio(struct rt_rq *rt_rq, int prio)
{
	int prev_prio = rt_rq->highest_prio.curr;

	if (prio < prev_prio)
		rt_rq->highest_prio.curr = prio;

	inc_rt_prio_smp(rt_rq, prio, prev_prio);
}

static void
dec_rt_prio(struct rt_rq *rt_rq, int prio)
{
	int prev_prio = rt_rq->highest_prio.curr;

P
Peter Zijlstra 已提交
959
	if (rt_rq->rt_nr_running) {
960

961
		WARN_ON(prio < prev_prio);
962

963
		/*
964 965
		 * This may have been our highest task, and therefore
		 * we may have some recomputation to do
966
		 */
967
		if (prio == prev_prio) {
968 969 970
			struct rt_prio_array *array = &rt_rq->active;

			rt_rq->highest_prio.curr =
971
				sched_find_first_bit(array->bitmap);
972 973
		}

974
	} else
975
		rt_rq->highest_prio.curr = MAX_RT_PRIO;
976

977 978
	dec_rt_prio_smp(rt_rq, prio, prev_prio);
}
979

980 981 982 983 984 985
#else

static inline void inc_rt_prio(struct rt_rq *rt_rq, int prio) {}
static inline void dec_rt_prio(struct rt_rq *rt_rq, int prio) {}

#endif /* CONFIG_SMP || CONFIG_RT_GROUP_SCHED */
986

987
#ifdef CONFIG_RT_GROUP_SCHED
988 989 990 991 992 993 994 995 996 997 998 999 1000 1001

static void
inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
	if (rt_se_boosted(rt_se))
		rt_rq->rt_nr_boosted++;

	if (rt_rq->tg)
		start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
}

static void
dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
P
Peter Zijlstra 已提交
1002 1003 1004 1005
	if (rt_se_boosted(rt_se))
		rt_rq->rt_nr_boosted--;

	WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted);
1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043
}

#else /* CONFIG_RT_GROUP_SCHED */

static void
inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
	start_rt_bandwidth(&def_rt_bandwidth);
}

static inline
void dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) {}

#endif /* CONFIG_RT_GROUP_SCHED */

static inline
void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
	int prio = rt_se_prio(rt_se);

	WARN_ON(!rt_prio(prio));
	rt_rq->rt_nr_running++;

	inc_rt_prio(rt_rq, prio);
	inc_rt_migration(rt_se, rt_rq);
	inc_rt_group(rt_se, rt_rq);
}

static inline
void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
	WARN_ON(!rt_prio(rt_se_prio(rt_se)));
	WARN_ON(!rt_rq->rt_nr_running);
	rt_rq->rt_nr_running--;

	dec_rt_prio(rt_rq, rt_se_prio(rt_se));
	dec_rt_migration(rt_se, rt_rq);
	dec_rt_group(rt_se, rt_rq);
1044 1045
}

1046
static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head)
I
Ingo Molnar 已提交
1047
{
P
Peter Zijlstra 已提交
1048 1049 1050
	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);
1051
	struct list_head *queue = array->queue + rt_se_prio(rt_se);
I
Ingo Molnar 已提交
1052

1053 1054 1055 1056 1057 1058 1059
	/*
	 * 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))
P
Peter Zijlstra 已提交
1060
		return;
1061

1062 1063 1064
	if (!rt_rq->rt_nr_running)
		list_add_leaf_rt_rq(rt_rq);

1065 1066 1067 1068
	if (head)
		list_add(&rt_se->run_list, queue);
	else
		list_add_tail(&rt_se->run_list, queue);
P
Peter Zijlstra 已提交
1069
	__set_bit(rt_se_prio(rt_se), array->bitmap);
1070

P
Peter Zijlstra 已提交
1071 1072 1073
	inc_rt_tasks(rt_se, rt_rq);
}

1074
static void __dequeue_rt_entity(struct sched_rt_entity *rt_se)
P
Peter Zijlstra 已提交
1075 1076 1077 1078 1079 1080 1081 1082 1083
{
	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);
1084 1085
	if (!rt_rq->rt_nr_running)
		list_del_leaf_rt_rq(rt_rq);
P
Peter Zijlstra 已提交
1086 1087 1088 1089 1090 1091
}

/*
 * Because the prio of an upper entry depends on the lower
 * entries, we must remove entries top - down.
 */
1092
static void dequeue_rt_stack(struct sched_rt_entity *rt_se)
P
Peter Zijlstra 已提交
1093
{
1094
	struct sched_rt_entity *back = NULL;
P
Peter Zijlstra 已提交
1095

1096 1097 1098 1099 1100 1101 1102
	for_each_sched_rt_entity(rt_se) {
		rt_se->back = back;
		back = rt_se;
	}

	for (rt_se = back; rt_se; rt_se = rt_se->back) {
		if (on_rt_rq(rt_se))
1103 1104 1105 1106
			__dequeue_rt_entity(rt_se);
	}
}

1107
static void enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head)
1108 1109 1110
{
	dequeue_rt_stack(rt_se);
	for_each_sched_rt_entity(rt_se)
1111
		__enqueue_rt_entity(rt_se, head);
1112 1113 1114 1115 1116 1117 1118 1119 1120 1121
}

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)
1122
			__enqueue_rt_entity(rt_se, false);
1123
	}
I
Ingo Molnar 已提交
1124 1125 1126 1127 1128
}

/*
 * Adding/removing a task to/from a priority array:
 */
1129
static void
1130
enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)
P
Peter Zijlstra 已提交
1131 1132 1133
{
	struct sched_rt_entity *rt_se = &p->rt;

1134
	if (flags & ENQUEUE_WAKEUP)
P
Peter Zijlstra 已提交
1135 1136
		rt_se->timeout = 0;

1137
	enqueue_rt_entity(rt_se, flags & ENQUEUE_HEAD);
1138

1139 1140
	if (!task_current(rq, p) && p->rt.nr_cpus_allowed > 1)
		enqueue_pushable_task(rq, p);
1141 1142

	inc_nr_running(rq);
P
Peter Zijlstra 已提交
1143 1144
}

1145
static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
I
Ingo Molnar 已提交
1146
{
P
Peter Zijlstra 已提交
1147
	struct sched_rt_entity *rt_se = &p->rt;
I
Ingo Molnar 已提交
1148

1149
	update_curr_rt(rq);
1150
	dequeue_rt_entity(rt_se);
1151

1152
	dequeue_pushable_task(rq, p);
1153 1154

	dec_nr_running(rq);
I
Ingo Molnar 已提交
1155 1156 1157
}

/*
1158 1159
 * Put task to the head or the end of the run list without the overhead of
 * dequeue followed by enqueue.
I
Ingo Molnar 已提交
1160
 */
1161 1162
static void
requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, int head)
P
Peter Zijlstra 已提交
1163
{
1164
	if (on_rt_rq(rt_se)) {
1165 1166 1167 1168 1169 1170 1171
		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);
1172
	}
P
Peter Zijlstra 已提交
1173 1174
}

1175
static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head)
I
Ingo Molnar 已提交
1176
{
P
Peter Zijlstra 已提交
1177 1178
	struct sched_rt_entity *rt_se = &p->rt;
	struct rt_rq *rt_rq;
I
Ingo Molnar 已提交
1179

P
Peter Zijlstra 已提交
1180 1181
	for_each_sched_rt_entity(rt_se) {
		rt_rq = rt_rq_of_se(rt_se);
1182
		requeue_rt_entity(rt_rq, rt_se, head);
P
Peter Zijlstra 已提交
1183
	}
I
Ingo Molnar 已提交
1184 1185
}

P
Peter Zijlstra 已提交
1186
static void yield_task_rt(struct rq *rq)
I
Ingo Molnar 已提交
1187
{
1188
	requeue_task_rt(rq, rq->curr, 0);
I
Ingo Molnar 已提交
1189 1190
}

1191
#ifdef CONFIG_SMP
1192 1193
static int find_lowest_rq(struct task_struct *task);

1194
static int
1195
select_task_rq_rt(struct task_struct *p, int sd_flag, int flags)
1196
{
1197 1198 1199 1200 1201
	struct task_struct *curr;
	struct rq *rq;
	int cpu;

	cpu = task_cpu(p);
1202

1203 1204 1205
	if (p->rt.nr_cpus_allowed == 1)
		goto out;

1206 1207 1208 1209
	/* For anything but wake ups, just return the task_cpu */
	if (sd_flag != SD_BALANCE_WAKE && sd_flag != SD_BALANCE_FORK)
		goto out;

1210 1211 1212 1213 1214
	rq = cpu_rq(cpu);

	rcu_read_lock();
	curr = ACCESS_ONCE(rq->curr); /* unlocked access */

1215
	/*
1216
	 * If the current task on @p's runqueue is an RT task, then
1217 1218 1219 1220
	 * try to see if we can wake this RT task up on another
	 * runqueue. Otherwise simply start this RT task
	 * on its current runqueue.
	 *
1221 1222 1223 1224 1225 1226 1227 1228 1229
	 * We want to avoid overloading runqueues. If the woken
	 * task is a higher priority, then it will stay on this CPU
	 * and the lower prio task should be moved to another CPU.
	 * Even though this will probably make the lower prio task
	 * lose its cache, we do not want to bounce a higher task
	 * around just because it gave up its CPU, perhaps for a
	 * lock?
	 *
	 * For equal prio tasks, we just let the scheduler sort it out.
1230 1231 1232 1233 1234 1235
	 *
	 * Otherwise, just let it ride on the affined RQ and the
	 * post-schedule router will push the preempted task away
	 *
	 * This test is optimistic, if we get it wrong the load-balancer
	 * will have to sort it out.
1236
	 */
1237 1238
	if (curr && unlikely(rt_task(curr)) &&
	    (curr->rt.nr_cpus_allowed < 2 ||
1239
	     curr->prio <= p->prio) &&
P
Peter Zijlstra 已提交
1240
	    (p->rt.nr_cpus_allowed > 1)) {
1241
		int target = find_lowest_rq(p);
1242

1243 1244
		if (target != -1)
			cpu = target;
1245
	}
1246
	rcu_read_unlock();
1247

1248
out:
1249
	return cpu;
1250
}
1251 1252 1253 1254 1255 1256

static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
{
	if (rq->curr->rt.nr_cpus_allowed == 1)
		return;

1257
	if (p->rt.nr_cpus_allowed != 1
1258 1259
	    && cpupri_find(&rq->rd->cpupri, p, NULL))
		return;
1260

1261 1262
	if (!cpupri_find(&rq->rd->cpupri, rq->curr, NULL))
		return;
1263 1264 1265 1266 1267 1268 1269 1270 1271 1272

	/*
	 * 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);
}

1273 1274
#endif /* CONFIG_SMP */

I
Ingo Molnar 已提交
1275 1276 1277
/*
 * Preempt the current task with a newly woken task if needed:
 */
P
Peter Zijlstra 已提交
1278
static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flags)
I
Ingo Molnar 已提交
1279
{
1280
	if (p->prio < rq->curr->prio) {
I
Ingo Molnar 已提交
1281
		resched_task(rq->curr);
1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297
		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.
	 */
1298
	if (p->prio == rq->curr->prio && !test_tsk_need_resched(rq->curr))
1299
		check_preempt_equal_prio(rq, p);
1300
#endif
I
Ingo Molnar 已提交
1301 1302
}

P
Peter Zijlstra 已提交
1303 1304
static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
						   struct rt_rq *rt_rq)
I
Ingo Molnar 已提交
1305
{
P
Peter Zijlstra 已提交
1306 1307
	struct rt_prio_array *array = &rt_rq->active;
	struct sched_rt_entity *next = NULL;
I
Ingo Molnar 已提交
1308 1309 1310 1311
	struct list_head *queue;
	int idx;

	idx = sched_find_first_bit(array->bitmap);
P
Peter Zijlstra 已提交
1312
	BUG_ON(idx >= MAX_RT_PRIO);
I
Ingo Molnar 已提交
1313 1314

	queue = array->queue + idx;
P
Peter Zijlstra 已提交
1315
	next = list_entry(queue->next, struct sched_rt_entity, run_list);
1316

P
Peter Zijlstra 已提交
1317 1318
	return next;
}
I
Ingo Molnar 已提交
1319

1320
static struct task_struct *_pick_next_task_rt(struct rq *rq)
P
Peter Zijlstra 已提交
1321 1322 1323 1324
{
	struct sched_rt_entity *rt_se;
	struct task_struct *p;
	struct rt_rq *rt_rq;
I
Ingo Molnar 已提交
1325

P
Peter Zijlstra 已提交
1326 1327
	rt_rq = &rq->rt;

1328
	if (!rt_rq->rt_nr_running)
P
Peter Zijlstra 已提交
1329 1330
		return NULL;

P
Peter Zijlstra 已提交
1331
	if (rt_rq_throttled(rt_rq))
P
Peter Zijlstra 已提交
1332 1333 1334 1335
		return NULL;

	do {
		rt_se = pick_next_rt_entity(rq, rt_rq);
1336
		BUG_ON(!rt_se);
P
Peter Zijlstra 已提交
1337 1338 1339 1340
		rt_rq = group_rt_rq(rt_se);
	} while (rt_rq);

	p = rt_task_of(rt_se);
1341
	p->se.exec_start = rq->clock_task;
1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353

	return p;
}

static struct task_struct *pick_next_task_rt(struct rq *rq)
{
	struct task_struct *p = _pick_next_task_rt(rq);

	/* The running task is never eligible for pushing */
	if (p)
		dequeue_pushable_task(rq, p);

1354
#ifdef CONFIG_SMP
1355 1356 1357 1358 1359
	/*
	 * 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);
1360
#endif
1361

P
Peter Zijlstra 已提交
1362
	return p;
I
Ingo Molnar 已提交
1363 1364
}

1365
static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
I
Ingo Molnar 已提交
1366
{
1367
	update_curr_rt(rq);
1368 1369 1370 1371 1372

	/*
	 * The previous task needs to be made eligible for pushing
	 * if it is still active
	 */
P
Peter Zijlstra 已提交
1373
	if (on_rt_rq(&p->rt) && p->rt.nr_cpus_allowed > 1)
1374
		enqueue_pushable_task(rq, p);
I
Ingo Molnar 已提交
1375 1376
}

1377
#ifdef CONFIG_SMP
P
Peter Zijlstra 已提交
1378

S
Steven Rostedt 已提交
1379 1380 1381
/* Only try algorithms three times */
#define RT_MAX_TRIES 3

1382 1383 1384
static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
{
	if (!task_running(rq, p) &&
1385
	    (cpu < 0 || cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) &&
P
Peter Zijlstra 已提交
1386
	    (p->rt.nr_cpus_allowed > 1))
1387 1388 1389 1390
		return 1;
	return 0;
}

S
Steven Rostedt 已提交
1391
/* Return the second highest RT task, NULL otherwise */
1392
static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu)
S
Steven Rostedt 已提交
1393
{
P
Peter Zijlstra 已提交
1394 1395 1396 1397
	struct task_struct *next = NULL;
	struct sched_rt_entity *rt_se;
	struct rt_prio_array *array;
	struct rt_rq *rt_rq;
S
Steven Rostedt 已提交
1398 1399
	int idx;

P
Peter Zijlstra 已提交
1400 1401 1402
	for_each_leaf_rt_rq(rt_rq, rq) {
		array = &rt_rq->active;
		idx = sched_find_first_bit(array->bitmap);
P
Peter Zijlstra 已提交
1403
next_idx:
P
Peter Zijlstra 已提交
1404 1405 1406 1407 1408
		if (idx >= MAX_RT_PRIO)
			continue;
		if (next && next->prio < idx)
			continue;
		list_for_each_entry(rt_se, array->queue + idx, run_list) {
1409 1410 1411 1412 1413 1414
			struct task_struct *p;

			if (!rt_entity_is_task(rt_se))
				continue;

			p = rt_task_of(rt_se);
P
Peter Zijlstra 已提交
1415 1416 1417 1418 1419 1420 1421 1422 1423
			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;
		}
1424 1425
	}

S
Steven Rostedt 已提交
1426 1427 1428
	return next;
}

1429
static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask);
S
Steven Rostedt 已提交
1430

G
Gregory Haskins 已提交
1431 1432 1433
static int find_lowest_rq(struct task_struct *task)
{
	struct sched_domain *sd;
1434
	struct cpumask *lowest_mask = __get_cpu_var(local_cpu_mask);
G
Gregory Haskins 已提交
1435 1436
	int this_cpu = smp_processor_id();
	int cpu      = task_cpu(task);
G
Gregory Haskins 已提交
1437

1438 1439 1440 1441
	/* Make sure the mask is initialized first */
	if (unlikely(!lowest_mask))
		return -1;

1442 1443
	if (task->rt.nr_cpus_allowed == 1)
		return -1; /* No other targets possible */
G
Gregory Haskins 已提交
1444

1445 1446
	if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask))
		return -1; /* No targets found */
G
Gregory Haskins 已提交
1447 1448 1449 1450 1451 1452 1453 1454 1455

	/*
	 * 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.
	 *
	 * We prioritize the last cpu that the task executed on since
	 * it is most likely cache-hot in that location.
	 */
1456
	if (cpumask_test_cpu(cpu, lowest_mask))
G
Gregory Haskins 已提交
1457 1458 1459 1460 1461 1462
		return cpu;

	/*
	 * Otherwise, we consult the sched_domains span maps to figure
	 * out which cpu is logically closest to our hot cache data.
	 */
R
Rusty Russell 已提交
1463 1464
	if (!cpumask_test_cpu(this_cpu, lowest_mask))
		this_cpu = -1; /* Skip this_cpu opt if not among lowest */
G
Gregory Haskins 已提交
1465

1466
	rcu_read_lock();
R
Rusty Russell 已提交
1467 1468 1469
	for_each_domain(cpu, sd) {
		if (sd->flags & SD_WAKE_AFFINE) {
			int best_cpu;
G
Gregory Haskins 已提交
1470

R
Rusty Russell 已提交
1471 1472 1473 1474 1475
			/*
			 * "this_cpu" is cheaper to preempt than a
			 * remote processor.
			 */
			if (this_cpu != -1 &&
1476 1477
			    cpumask_test_cpu(this_cpu, sched_domain_span(sd))) {
				rcu_read_unlock();
R
Rusty Russell 已提交
1478
				return this_cpu;
1479
			}
R
Rusty Russell 已提交
1480 1481 1482

			best_cpu = cpumask_first_and(lowest_mask,
						     sched_domain_span(sd));
1483 1484
			if (best_cpu < nr_cpu_ids) {
				rcu_read_unlock();
R
Rusty Russell 已提交
1485
				return best_cpu;
1486
			}
G
Gregory Haskins 已提交
1487 1488
		}
	}
1489
	rcu_read_unlock();
G
Gregory Haskins 已提交
1490 1491 1492 1493 1494 1495

	/*
	 * And finally, if there were no matches within the domains
	 * just give the caller *something* to work with from the compatible
	 * locations.
	 */
R
Rusty Russell 已提交
1496 1497 1498 1499 1500 1501 1502
	if (this_cpu != -1)
		return this_cpu;

	cpu = cpumask_any(lowest_mask);
	if (cpu < nr_cpu_ids)
		return cpu;
	return -1;
1503 1504 1505
}

/* Will lock the rq it finds */
1506
static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
1507 1508 1509
{
	struct rq *lowest_rq = NULL;
	int tries;
1510
	int cpu;
S
Steven Rostedt 已提交
1511

1512 1513 1514
	for (tries = 0; tries < RT_MAX_TRIES; tries++) {
		cpu = find_lowest_rq(task);

1515
		if ((cpu == -1) || (cpu == rq->cpu))
S
Steven Rostedt 已提交
1516 1517
			break;

1518 1519
		lowest_rq = cpu_rq(cpu);

S
Steven Rostedt 已提交
1520
		/* if the prio of this runqueue changed, try again */
1521
		if (double_lock_balance(rq, lowest_rq)) {
S
Steven Rostedt 已提交
1522 1523 1524 1525 1526 1527
			/*
			 * We had to unlock the run queue. In
			 * the mean time, task could have
			 * migrated already or had its affinity changed.
			 * Also make sure that it wasn't scheduled on its rq.
			 */
1528
			if (unlikely(task_rq(task) != rq ||
1529
				     !cpumask_test_cpu(lowest_rq->cpu,
1530
						       tsk_cpus_allowed(task)) ||
1531
				     task_running(rq, task) ||
P
Peter Zijlstra 已提交
1532
				     !task->on_rq)) {
1533

1534
				raw_spin_unlock(&lowest_rq->lock);
S
Steven Rostedt 已提交
1535 1536 1537 1538 1539 1540
				lowest_rq = NULL;
				break;
			}
		}

		/* If this rq is still suitable use it. */
1541
		if (lowest_rq->rt.highest_prio.curr > task->prio)
S
Steven Rostedt 已提交
1542 1543 1544
			break;

		/* try again */
1545
		double_unlock_balance(rq, lowest_rq);
S
Steven Rostedt 已提交
1546 1547 1548 1549 1550 1551
		lowest_rq = NULL;
	}

	return lowest_rq;
}

1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565
static struct task_struct *pick_next_pushable_task(struct rq *rq)
{
	struct task_struct *p;

	if (!has_pushable_tasks(rq))
		return NULL;

	p = plist_first_entry(&rq->rt.pushable_tasks,
			      struct task_struct, pushable_tasks);

	BUG_ON(rq->cpu != task_cpu(p));
	BUG_ON(task_current(rq, p));
	BUG_ON(p->rt.nr_cpus_allowed <= 1);

P
Peter Zijlstra 已提交
1566
	BUG_ON(!p->on_rq);
1567 1568 1569 1570 1571
	BUG_ON(!rt_task(p));

	return p;
}

S
Steven Rostedt 已提交
1572 1573 1574 1575 1576
/*
 * If the current CPU has more than one RT task, see if the non
 * running task can migrate over to a CPU that is running a task
 * of lesser priority.
 */
1577
static int push_rt_task(struct rq *rq)
S
Steven Rostedt 已提交
1578 1579 1580
{
	struct task_struct *next_task;
	struct rq *lowest_rq;
1581
	int ret = 0;
S
Steven Rostedt 已提交
1582

G
Gregory Haskins 已提交
1583 1584 1585
	if (!rq->rt.overloaded)
		return 0;

1586
	next_task = pick_next_pushable_task(rq);
S
Steven Rostedt 已提交
1587 1588 1589
	if (!next_task)
		return 0;

1590 1591 1592 1593 1594
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
       if (unlikely(task_running(rq, next_task)))
               return 0;
#endif

P
Peter Zijlstra 已提交
1595
retry:
1596
	if (unlikely(next_task == rq->curr)) {
1597
		WARN_ON(1);
S
Steven Rostedt 已提交
1598
		return 0;
1599
	}
S
Steven Rostedt 已提交
1600 1601 1602 1603 1604 1605

	/*
	 * It's possible that the next_task slipped in of
	 * higher priority than current. If that's the case
	 * just reschedule current.
	 */
1606 1607
	if (unlikely(next_task->prio < rq->curr->prio)) {
		resched_task(rq->curr);
S
Steven Rostedt 已提交
1608 1609 1610
		return 0;
	}

1611
	/* We might release rq lock */
S
Steven Rostedt 已提交
1612 1613 1614
	get_task_struct(next_task);

	/* find_lock_lowest_rq locks the rq if found */
1615
	lowest_rq = find_lock_lowest_rq(next_task, rq);
S
Steven Rostedt 已提交
1616 1617 1618
	if (!lowest_rq) {
		struct task_struct *task;
		/*
1619
		 * find_lock_lowest_rq releases rq->lock
1620 1621 1622 1623 1624
		 * so it is possible that next_task has migrated.
		 *
		 * We need to make sure that the task is still on the same
		 * run-queue and is also still the next task eligible for
		 * pushing.
S
Steven Rostedt 已提交
1625
		 */
1626
		task = pick_next_pushable_task(rq);
1627 1628
		if (task_cpu(next_task) == rq->cpu && task == next_task) {
			/*
1629 1630 1631 1632
			 * The task hasn't migrated, and is still the next
			 * eligible task, but we failed to find a run-queue
			 * to push it to.  Do not retry in this case, since
			 * other cpus will pull from us when ready.
1633 1634
			 */
			goto out;
S
Steven Rostedt 已提交
1635
		}
1636

1637 1638 1639 1640
		if (!task)
			/* No more tasks, just exit */
			goto out;

1641
		/*
1642
		 * Something has shifted, try again.
1643
		 */
1644 1645 1646
		put_task_struct(next_task);
		next_task = task;
		goto retry;
S
Steven Rostedt 已提交
1647 1648
	}

1649
	deactivate_task(rq, next_task, 0);
S
Steven Rostedt 已提交
1650 1651
	set_task_cpu(next_task, lowest_rq->cpu);
	activate_task(lowest_rq, next_task, 0);
1652
	ret = 1;
S
Steven Rostedt 已提交
1653 1654 1655

	resched_task(lowest_rq->curr);

1656
	double_unlock_balance(rq, lowest_rq);
S
Steven Rostedt 已提交
1657 1658 1659 1660

out:
	put_task_struct(next_task);

1661
	return ret;
S
Steven Rostedt 已提交
1662 1663 1664 1665 1666 1667 1668 1669 1670
}

static void push_rt_tasks(struct rq *rq)
{
	/* push_rt_task will return true if it moved an RT */
	while (push_rt_task(rq))
		;
}

1671 1672
static int pull_rt_task(struct rq *this_rq)
{
I
Ingo Molnar 已提交
1673
	int this_cpu = this_rq->cpu, ret = 0, cpu;
1674
	struct task_struct *p;
1675 1676
	struct rq *src_rq;

1677
	if (likely(!rt_overloaded(this_rq)))
1678 1679
		return 0;

1680
	for_each_cpu(cpu, this_rq->rd->rto_mask) {
1681 1682 1683 1684
		if (this_cpu == cpu)
			continue;

		src_rq = cpu_rq(cpu);
1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696

		/*
		 * Don't bother taking the src_rq->lock if the next highest
		 * task is known to be lower-priority than our current task.
		 * This may look racy, but if this value is about to go
		 * logically higher, the src_rq will push this task away.
		 * And if its going logically lower, we do not care
		 */
		if (src_rq->rt.highest_prio.next >=
		    this_rq->rt.highest_prio.curr)
			continue;

1697 1698 1699
		/*
		 * We can potentially drop this_rq's lock in
		 * double_lock_balance, and another CPU could
1700
		 * alter this_rq
1701
		 */
1702
		double_lock_balance(this_rq, src_rq);
1703 1704 1705 1706

		/*
		 * Are there still pullable RT tasks?
		 */
M
Mike Galbraith 已提交
1707 1708
		if (src_rq->rt.rt_nr_running <= 1)
			goto skip;
1709 1710 1711 1712 1713 1714 1715

		p = pick_next_highest_task_rt(src_rq, this_cpu);

		/*
		 * Do we have an RT task that preempts
		 * the to-be-scheduled task?
		 */
1716
		if (p && (p->prio < this_rq->rt.highest_prio.curr)) {
1717
			WARN_ON(p == src_rq->curr);
P
Peter Zijlstra 已提交
1718
			WARN_ON(!p->on_rq);
1719 1720 1721 1722 1723 1724 1725

			/*
			 * There's a chance that p is higher in priority
			 * than what's currently running on its cpu.
			 * This is just that p is wakeing up and hasn't
			 * had a chance to schedule. We only pull
			 * p if it is lower in priority than the
1726
			 * current task on the run queue
1727
			 */
1728
			if (p->prio < src_rq->curr->prio)
M
Mike Galbraith 已提交
1729
				goto skip;
1730 1731 1732 1733 1734 1735 1736 1737 1738

			ret = 1;

			deactivate_task(src_rq, p, 0);
			set_task_cpu(p, this_cpu);
			activate_task(this_rq, p, 0);
			/*
			 * We continue with the search, just in
			 * case there's an even higher prio task
L
Lucas De Marchi 已提交
1739
			 * in another runqueue. (low likelihood
1740 1741 1742
			 * but possible)
			 */
		}
P
Peter Zijlstra 已提交
1743
skip:
1744
		double_unlock_balance(this_rq, src_rq);
1745 1746 1747 1748 1749
	}

	return ret;
}

1750
static void pre_schedule_rt(struct rq *rq, struct task_struct *prev)
1751 1752
{
	/* Try to pull RT tasks here if we lower this rq's prio */
Y
Yong Zhang 已提交
1753
	if (rq->rt.highest_prio.curr > prev->prio)
1754 1755 1756
		pull_rt_task(rq);
}

1757
static void post_schedule_rt(struct rq *rq)
S
Steven Rostedt 已提交
1758
{
1759
	push_rt_tasks(rq);
S
Steven Rostedt 已提交
1760 1761
}

1762 1763 1764 1765
/*
 * If we are not running and we are not going to reschedule soon, we should
 * try to push tasks away now
 */
1766
static void task_woken_rt(struct rq *rq, struct task_struct *p)
1767
{
1768
	if (!task_running(rq, p) &&
1769
	    !test_tsk_need_resched(rq->curr) &&
1770
	    has_pushable_tasks(rq) &&
1771
	    p->rt.nr_cpus_allowed > 1 &&
1772
	    rt_task(rq->curr) &&
1773
	    (rq->curr->rt.nr_cpus_allowed < 2 ||
1774
	     rq->curr->prio <= p->prio))
1775 1776 1777
		push_rt_tasks(rq);
}

1778
static void set_cpus_allowed_rt(struct task_struct *p,
1779
				const struct cpumask *new_mask)
1780
{
1781
	int weight = cpumask_weight(new_mask);
1782 1783 1784 1785 1786 1787 1788

	BUG_ON(!rt_task(p));

	/*
	 * Update the migration status of the RQ if we have an RT task
	 * which is running AND changing its weight value.
	 */
P
Peter Zijlstra 已提交
1789
	if (p->on_rq && (weight != p->rt.nr_cpus_allowed)) {
1790 1791
		struct rq *rq = task_rq(p);

1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809
		if (!task_current(rq, p)) {
			/*
			 * Make sure we dequeue this task from the pushable list
			 * before going further.  It will either remain off of
			 * the list because we are no longer pushable, or it
			 * will be requeued.
			 */
			if (p->rt.nr_cpus_allowed > 1)
				dequeue_pushable_task(rq, p);

			/*
			 * Requeue if our weight is changing and still > 1
			 */
			if (weight > 1)
				enqueue_pushable_task(rq, p);

		}

P
Peter Zijlstra 已提交
1810
		if ((p->rt.nr_cpus_allowed <= 1) && (weight > 1)) {
1811
			rq->rt.rt_nr_migratory++;
P
Peter Zijlstra 已提交
1812
		} else if ((p->rt.nr_cpus_allowed > 1) && (weight <= 1)) {
1813 1814 1815 1816
			BUG_ON(!rq->rt.rt_nr_migratory);
			rq->rt.rt_nr_migratory--;
		}

1817
		update_rt_migration(&rq->rt);
1818 1819
	}
}
1820

1821
/* Assumes rq->lock is held */
1822
static void rq_online_rt(struct rq *rq)
1823 1824 1825
{
	if (rq->rt.overloaded)
		rt_set_overload(rq);
1826

P
Peter Zijlstra 已提交
1827 1828
	__enable_runtime(rq);

1829
	cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr);
1830 1831 1832
}

/* Assumes rq->lock is held */
1833
static void rq_offline_rt(struct rq *rq)
1834 1835 1836
{
	if (rq->rt.overloaded)
		rt_clear_overload(rq);
1837

P
Peter Zijlstra 已提交
1838 1839
	__disable_runtime(rq);

1840
	cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID);
1841
}
1842 1843 1844 1845 1846

/*
 * When switch from the rt queue, we bring ourselves to a position
 * that we might want to pull RT tasks from other runqueues.
 */
P
Peter Zijlstra 已提交
1847
static void switched_from_rt(struct rq *rq, struct task_struct *p)
1848 1849 1850 1851 1852 1853 1854 1855
{
	/*
	 * If there are other RT tasks then we will reschedule
	 * and the scheduling of the other RT tasks will handle
	 * the balancing. But if we are the last RT task
	 * we may need to handle the pulling of RT tasks
	 * now.
	 */
P
Peter Zijlstra 已提交
1856
	if (p->on_rq && !rq->rt.rt_nr_running)
1857 1858
		pull_rt_task(rq);
}
1859

1860
void init_sched_rt_class(void)
1861 1862 1863
{
	unsigned int i;

1864
	for_each_possible_cpu(i) {
1865
		zalloc_cpumask_var_node(&per_cpu(local_cpu_mask, i),
1866
					GFP_KERNEL, cpu_to_node(i));
1867
	}
1868
}
1869 1870 1871 1872 1873 1874 1875
#endif /* CONFIG_SMP */

/*
 * When switching a task to RT, we may overload the runqueue
 * with RT tasks. In this case we try to push them off to
 * other runqueues.
 */
P
Peter Zijlstra 已提交
1876
static void switched_to_rt(struct rq *rq, struct task_struct *p)
1877 1878 1879 1880 1881 1882 1883 1884 1885 1886
{
	int check_resched = 1;

	/*
	 * If we are already running, then there's nothing
	 * that needs to be done. But if we are not running
	 * we may need to preempt the current running task.
	 * If that current running task is also an RT task
	 * then see if we can move to another run queue.
	 */
P
Peter Zijlstra 已提交
1887
	if (p->on_rq && rq->curr != p) {
1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902
#ifdef CONFIG_SMP
		if (rq->rt.overloaded && push_rt_task(rq) &&
		    /* Don't resched if we changed runqueues */
		    rq != task_rq(p))
			check_resched = 0;
#endif /* CONFIG_SMP */
		if (check_resched && p->prio < rq->curr->prio)
			resched_task(rq->curr);
	}
}

/*
 * Priority of the task has changed. This may cause
 * us to initiate a push or pull.
 */
P
Peter Zijlstra 已提交
1903 1904
static void
prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
1905
{
P
Peter Zijlstra 已提交
1906
	if (!p->on_rq)
P
Peter Zijlstra 已提交
1907 1908 1909
		return;

	if (rq->curr == p) {
1910 1911 1912 1913 1914 1915 1916 1917 1918
#ifdef CONFIG_SMP
		/*
		 * If our priority decreases while running, we
		 * may need to pull tasks to this runqueue.
		 */
		if (oldprio < p->prio)
			pull_rt_task(rq);
		/*
		 * If there's a higher priority task waiting to run
1919 1920 1921
		 * then reschedule. Note, the above pull_rt_task
		 * can release the rq lock and p could migrate.
		 * Only reschedule if p is still on the same runqueue.
1922
		 */
1923
		if (p->prio > rq->rt.highest_prio.curr && rq->curr == p)
1924 1925 1926 1927 1928
			resched_task(p);
#else
		/* For UP simply resched on drop of prio */
		if (oldprio < p->prio)
			resched_task(p);
S
Steven Rostedt 已提交
1929
#endif /* CONFIG_SMP */
1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940
	} else {
		/*
		 * This task is not running, but if it is
		 * greater than the current running task
		 * then reschedule.
		 */
		if (p->prio < rq->curr->prio)
			resched_task(rq->curr);
	}
}

1941 1942 1943 1944
static void watchdog(struct rq *rq, struct task_struct *p)
{
	unsigned long soft, hard;

1945 1946 1947
	/* max may change after cur was read, this will be fixed next tick */
	soft = task_rlimit(p, RLIMIT_RTTIME);
	hard = task_rlimit_max(p, RLIMIT_RTTIME);
1948 1949 1950 1951 1952 1953

	if (soft != RLIM_INFINITY) {
		unsigned long next;

		p->rt.timeout++;
		next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ);
1954
		if (p->rt.timeout > next)
1955
			p->cputime_expires.sched_exp = p->se.sum_exec_runtime;
1956 1957
	}
}
I
Ingo Molnar 已提交
1958

P
Peter Zijlstra 已提交
1959
static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
I
Ingo Molnar 已提交
1960
{
1961 1962
	update_curr_rt(rq);

1963 1964
	watchdog(rq, p);

I
Ingo Molnar 已提交
1965 1966 1967 1968 1969 1970 1971
	/*
	 * RR tasks need a special form of timeslice management.
	 * FIFO tasks have no timeslices.
	 */
	if (p->policy != SCHED_RR)
		return;

P
Peter Zijlstra 已提交
1972
	if (--p->rt.time_slice)
I
Ingo Molnar 已提交
1973 1974
		return;

1975
	p->rt.time_slice = RR_TIMESLICE;
I
Ingo Molnar 已提交
1976

1977 1978 1979 1980
	/*
	 * Requeue to the end of queue if we are not the only element
	 * on the queue:
	 */
P
Peter Zijlstra 已提交
1981
	if (p->rt.run_list.prev != p->rt.run_list.next) {
1982
		requeue_task_rt(rq, p, 0);
1983 1984
		set_tsk_need_resched(p);
	}
I
Ingo Molnar 已提交
1985 1986
}

1987 1988 1989 1990
static void set_curr_task_rt(struct rq *rq)
{
	struct task_struct *p = rq->curr;

1991
	p->se.exec_start = rq->clock_task;
1992 1993 1994

	/* The running task is never eligible for pushing */
	dequeue_pushable_task(rq, p);
1995 1996
}

1997
static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task)
1998 1999 2000 2001 2002
{
	/*
	 * Time slice is 0 for SCHED_FIFO tasks
	 */
	if (task->policy == SCHED_RR)
2003
		return RR_TIMESLICE;
2004 2005 2006 2007
	else
		return 0;
}

2008
const struct sched_class rt_sched_class = {
2009
	.next			= &fair_sched_class,
I
Ingo Molnar 已提交
2010 2011 2012 2013 2014 2015 2016 2017 2018
	.enqueue_task		= enqueue_task_rt,
	.dequeue_task		= dequeue_task_rt,
	.yield_task		= yield_task_rt,

	.check_preempt_curr	= check_preempt_curr_rt,

	.pick_next_task		= pick_next_task_rt,
	.put_prev_task		= put_prev_task_rt,

2019
#ifdef CONFIG_SMP
L
Li Zefan 已提交
2020 2021
	.select_task_rq		= select_task_rq_rt,

2022
	.set_cpus_allowed       = set_cpus_allowed_rt,
2023 2024
	.rq_online              = rq_online_rt,
	.rq_offline             = rq_offline_rt,
2025 2026
	.pre_schedule		= pre_schedule_rt,
	.post_schedule		= post_schedule_rt,
2027
	.task_woken		= task_woken_rt,
2028
	.switched_from		= switched_from_rt,
2029
#endif
I
Ingo Molnar 已提交
2030

2031
	.set_curr_task          = set_curr_task_rt,
I
Ingo Molnar 已提交
2032
	.task_tick		= task_tick_rt,
2033

2034 2035
	.get_rr_interval	= get_rr_interval_rt,

2036 2037
	.prio_changed		= prio_changed_rt,
	.switched_to		= switched_to_rt,
I
Ingo Molnar 已提交
2038
};
2039 2040 2041 2042

#ifdef CONFIG_SCHED_DEBUG
extern void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq);

2043
void print_rt_stats(struct seq_file *m, int cpu)
2044
{
C
Cheng Xu 已提交
2045
	rt_rq_iter_t iter;
2046 2047 2048
	struct rt_rq *rt_rq;

	rcu_read_lock();
C
Cheng Xu 已提交
2049
	for_each_rt_rq(rt_rq, iter, cpu_rq(cpu))
2050 2051 2052
		print_rt_rq(m, cpu, rt_rq);
	rcu_read_unlock();
}
2053
#endif /* CONFIG_SCHED_DEBUG */