Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
Branch: master
Fetching contributors…

Cannot retrieve contributors at this time

1855 lines (1503 sloc) 43.2 kB
/*
* Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR
* policies)
*/
#ifdef CONFIG_RT_GROUP_SCHED
#define rt_entity_is_task(rt_se) (!(rt_se)->my_q)
static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
{
#ifdef CONFIG_SCHED_DEBUG
WARN_ON_ONCE(!rt_entity_is_task(rt_se));
#endif
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;
}
#else /* CONFIG_RT_GROUP_SCHED */
#define rt_entity_is_task(rt_se) (1)
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 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;
}
#endif /* CONFIG_RT_GROUP_SCHED */
#ifdef CONFIG_SMP
static inline int rt_overloaded(struct rq *rq)
{
return atomic_read(&rq->rd->rto_count);
}
static inline void rt_set_overload(struct rq *rq)
{
if (!rq->online)
return;
cpumask_set_cpu(rq->cpu, rq->rd->rto_mask);
/*
* 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();
atomic_inc(&rq->rd->rto_count);
}
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);
cpumask_clear_cpu(rq->cpu, rq->rd->rto_mask);
}
static void update_rt_migration(struct rt_rq *rt_rq)
{
if (rt_rq->rt_nr_migratory && rt_rq->rt_nr_total > 1) {
if (!rt_rq->overloaded) {
rt_set_overload(rq_of_rt_rq(rt_rq));
rt_rq->overloaded = 1;
}
} else if (rt_rq->overloaded) {
rt_clear_overload(rq_of_rt_rq(rt_rq));
rt_rq->overloaded = 0;
}
}
static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
if (!rt_entity_is_task(rt_se))
return;
rt_rq = &rq_of_rt_rq(rt_rq)->rt;
rt_rq->rt_nr_total++;
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)
{
if (!rt_entity_is_task(rt_se))
return;
rt_rq = &rq_of_rt_rq(rt_rq)->rt;
rt_rq->rt_nr_total--;
if (rt_se->nr_cpus_allowed > 1)
rt_rq->rt_nr_migratory--;
update_rt_migration(rt_rq);
}
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);
}
static void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
{
plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
}
static inline int has_pushable_tasks(struct rq *rq)
{
return !plist_head_empty(&rq->rt.pushable_tasks);
}
#else
static inline void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
{
}
static inline void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
{
}
static inline
void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
}
static inline
void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
}
#endif /* CONFIG_SMP */
static inline int on_rt_rq(struct sched_rt_entity *rt_se)
{
return !list_empty(&rt_se->run_list);
}
#ifdef CONFIG_RT_GROUP_SCHED
static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
{
if (!rt_rq->tg)
return RUNTIME_INF;
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);
}
typedef struct task_group *rt_rq_iter_t;
#define for_each_rt_rq(rt_rq, iter, rq) \
for (iter = list_entry_rcu(task_groups.next, typeof(*iter), list); \
(&iter->list != &task_groups) && \
(rt_rq = iter->rt_rq[cpu_of(rq)]); \
iter = list_entry_rcu(iter->list.next, typeof(*iter), list))
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);
}
#define for_each_leaf_rt_rq(rt_rq, rq) \
list_for_each_entry_rcu(rt_rq, &rq->leaf_rt_rq_list, leaf_rt_rq_list)
#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, bool head);
static void dequeue_rt_entity(struct sched_rt_entity *rt_se);
static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
{
struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
struct sched_rt_entity *rt_se;
int cpu = cpu_of(rq_of_rt_rq(rt_rq));
rt_se = rt_rq->tg->rt_se[cpu];
if (rt_rq->rt_nr_running) {
if (rt_se && !on_rt_rq(rt_se))
enqueue_rt_entity(rt_se, false);
if (rt_rq->highest_prio.curr < curr->prio)
resched_task(curr);
}
}
static void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
{
struct sched_rt_entity *rt_se;
int cpu = cpu_of(rq_of_rt_rq(rt_rq));
rt_se = rt_rq->tg->rt_se[cpu];
if (rt_se && on_rt_rq(rt_se))
dequeue_rt_entity(rt_se);
}
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;
}
#ifdef CONFIG_SMP
static inline const struct cpumask *sched_rt_period_mask(void)
{
return cpu_rq(smp_processor_id())->rd->span;
}
#else
static inline const struct cpumask *sched_rt_period_mask(void)
{
return cpu_online_mask;
}
#endif
static inline
struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
{
return container_of(rt_b, struct task_group, rt_bandwidth)->rt_rq[cpu];
}
static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
{
return &rt_rq->tg->rt_bandwidth;
}
#else /* !CONFIG_RT_GROUP_SCHED */
static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
{
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);
}
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)
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)
{
}
#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;
}
static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
{
if (rt_rq->rt_nr_running)
resched_task(rq_of_rt_rq(rt_rq)->curr);
}
static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
{
}
static inline int rt_rq_throttled(struct rt_rq *rt_rq)
{
return rt_rq->rt_throttled;
}
static inline const struct cpumask *sched_rt_period_mask(void)
{
return cpu_online_mask;
}
static inline
struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
{
return &cpu_rq(cpu)->rt;
}
static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
{
return &def_rt_bandwidth;
}
#endif /* CONFIG_RT_GROUP_SCHED */
#ifdef CONFIG_SMP
/*
* We ran out of runtime, see if we can borrow some from our neighbours.
*/
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 = cpumask_weight(rd->span);
raw_spin_lock(&rt_b->rt_runtime_lock);
rt_period = ktime_to_ns(rt_b->rt_period);
for_each_cpu(i, rd->span) {
struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
s64 diff;
if (iter == rt_rq)
continue;
raw_spin_lock(&iter->rt_runtime_lock);
/*
* 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.
*/
if (iter->rt_runtime == RUNTIME_INF)
goto next;
/*
* From runqueues with spare time, take 1/n part of their
* spare time, but no more than our period.
*/
diff = iter->rt_runtime - iter->rt_time;
if (diff > 0) {
diff = div_u64((u64)diff, weight);
if (rt_rq->rt_runtime + diff > rt_period)
diff = rt_period - rt_rq->rt_runtime;
iter->rt_runtime -= diff;
rt_rq->rt_runtime += diff;
more = 1;
if (rt_rq->rt_runtime == rt_period) {
raw_spin_unlock(&iter->rt_runtime_lock);
break;
}
}
next:
raw_spin_unlock(&iter->rt_runtime_lock);
}
raw_spin_unlock(&rt_b->rt_runtime_lock);
return more;
}
/*
* Ensure this RQ takes back all the runtime it lend to its neighbours.
*/
static void __disable_runtime(struct rq *rq)
{
struct root_domain *rd = rq->rd;
rt_rq_iter_t iter;
struct rt_rq *rt_rq;
if (unlikely(!scheduler_running))
return;
for_each_rt_rq(rt_rq, iter, rq) {
struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
s64 want;
int i;
raw_spin_lock(&rt_b->rt_runtime_lock);
raw_spin_lock(&rt_rq->rt_runtime_lock);
/*
* 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.
*/
if (rt_rq->rt_runtime == RUNTIME_INF ||
rt_rq->rt_runtime == rt_b->rt_runtime)
goto balanced;
raw_spin_unlock(&rt_rq->rt_runtime_lock);
/*
* 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.
*/
want = rt_b->rt_runtime - rt_rq->rt_runtime;
/*
* Greedy reclaim, take back as much as we can.
*/
for_each_cpu(i, rd->span) {
struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
s64 diff;
/*
* Can't reclaim from ourselves or disabled runqueues.
*/
if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
continue;
raw_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;
}
raw_spin_unlock(&iter->rt_runtime_lock);
if (!want)
break;
}
raw_spin_lock(&rt_rq->rt_runtime_lock);
/*
* We cannot be left wanting - that would mean some runtime
* leaked out of the system.
*/
BUG_ON(want);
balanced:
/*
* Disable all the borrow logic by pretending we have inf
* runtime - in which case borrowing doesn't make sense.
*/
rt_rq->rt_runtime = RUNTIME_INF;
raw_spin_unlock(&rt_rq->rt_runtime_lock);
raw_spin_unlock(&rt_b->rt_runtime_lock);
}
}
static void disable_runtime(struct rq *rq)
{
unsigned long flags;
raw_spin_lock_irqsave(&rq->lock, flags);
__disable_runtime(rq);
raw_spin_unlock_irqrestore(&rq->lock, flags);
}
static void __enable_runtime(struct rq *rq)
{
rt_rq_iter_t iter;
struct rt_rq *rt_rq;
if (unlikely(!scheduler_running))
return;
/*
* Reset each runqueue's bandwidth settings
*/
for_each_rt_rq(rt_rq, iter, rq) {
struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
raw_spin_lock(&rt_b->rt_runtime_lock);
raw_spin_lock(&rt_rq->rt_runtime_lock);
rt_rq->rt_runtime = rt_b->rt_runtime;
rt_rq->rt_time = 0;
rt_rq->rt_throttled = 0;
raw_spin_unlock(&rt_rq->rt_runtime_lock);
raw_spin_unlock(&rt_b->rt_runtime_lock);
}
}
static void enable_runtime(struct rq *rq)
{
unsigned long flags;
raw_spin_lock_irqsave(&rq->lock, flags);
__enable_runtime(rq);
raw_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) {
raw_spin_unlock(&rt_rq->rt_runtime_lock);
more = do_balance_runtime(rt_rq);
raw_spin_lock(&rt_rq->rt_runtime_lock);
}
return more;
}
#else /* !CONFIG_SMP */
static inline int balance_runtime(struct rt_rq *rt_rq)
{
return 0;
}
#endif /* CONFIG_SMP */
static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
{
int i, idle = 1;
const struct cpumask *span;
if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
return 1;
span = sched_rt_period_mask();
for_each_cpu(i, span) {
int enqueue = 0;
struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i);
struct rq *rq = rq_of_rt_rq(rt_rq);
raw_spin_lock(&rq->lock);
if (rt_rq->rt_time) {
u64 runtime;
raw_spin_lock(&rt_rq->rt_runtime_lock);
if (rt_rq->rt_throttled)
balance_runtime(rt_rq);
runtime = rt_rq->rt_runtime;
rt_rq->rt_time -= min(rt_rq->rt_time, overrun*runtime);
if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) {
rt_rq->rt_throttled = 0;
enqueue = 1;
/*
* 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;
}
if (rt_rq->rt_time || rt_rq->rt_nr_running)
idle = 0;
raw_spin_unlock(&rt_rq->rt_runtime_lock);
} else if (rt_rq->rt_nr_running) {
idle = 0;
if (!rt_rq_throttled(rt_rq))
enqueue = 1;
}
if (enqueue)
sched_rt_rq_enqueue(rt_rq);
raw_spin_unlock(&rq->lock);
}
return idle;
}
static inline int rt_se_prio(struct sched_rt_entity *rt_se)
{
#ifdef CONFIG_RT_GROUP_SCHED
struct rt_rq *rt_rq = group_rt_rq(rt_se);
if (rt_rq)
return rt_rq->highest_prio.curr;
#endif
return rt_task_of(rt_se)->prio;
}
static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
{
u64 runtime = sched_rt_runtime(rt_rq);
if (rt_rq->rt_throttled)
return rt_rq_throttled(rt_rq);
if (sched_rt_runtime(rt_rq) >= sched_rt_period(rt_rq))
return 0;
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;
if (rt_rq_throttled(rt_rq)) {
sched_rt_rq_dequeue(rt_rq);
return 1;
}
}
return 0;
}
/*
* Update the current task's runtime statistics. Skip current tasks that
* are not in our scheduling class.
*/
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 (curr->sched_class != &rt_sched_class)
return;
delta_exec = rq->clock_task - curr->se.exec_start;
if (unlikely((s64)delta_exec < 0))
delta_exec = 0;
schedstat_set(curr->se.statistics.exec_max, max(curr->se.statistics.exec_max, delta_exec));
curr->se.sum_exec_runtime += delta_exec;
account_group_exec_runtime(curr, delta_exec);
curr->se.exec_start = rq->clock_task;
cpuacct_charge(curr, delta_exec);
sched_rt_avg_update(rq, delta_exec);
if (!rt_bandwidth_enabled())
return;
for_each_sched_rt_entity(rt_se) {
rt_rq = rt_rq_of_se(rt_se);
if (sched_rt_runtime(rt_rq) != RUNTIME_INF) {
raw_spin_lock(&rt_rq->rt_runtime_lock);
rt_rq->rt_time += delta_exec;
if (sched_rt_runtime_exceeded(rt_rq))
resched_task(curr);
raw_spin_unlock(&rt_rq->rt_runtime_lock);
}
}
}
#if defined CONFIG_SMP
static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu);
static inline int next_prio(struct rq *rq)
{
struct task_struct *next = pick_next_highest_task_rt(rq, rq->cpu);
if (next && rt_prio(next->prio))
return next->prio;
else
return MAX_RT_PRIO;
}
static void
inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
{
struct rq *rq = rq_of_rt_rq(rt_rq);
if (prio < prev_prio) {
/*
* If the new task is higher in priority than anything on the
* run-queue, we know that the previous high becomes our
* next-highest.
*/
rt_rq->highest_prio.next = prev_prio;
if (rq->online)
cpupri_set(&rq->rd->cpupri, rq->cpu, prio);
} else if (prio == rt_rq->highest_prio.curr)
/*
* If the next task is equal in priority to the highest on
* the run-queue, then we implicitly know that the next highest
* task cannot be any lower than current
*/
rt_rq->highest_prio.next = prio;
else if (prio < rt_rq->highest_prio.next)
/*
* Otherwise, we need to recompute next-highest
*/
rt_rq->highest_prio.next = next_prio(rq);
}
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);
if (rt_rq->rt_nr_running && (prio <= rt_rq->highest_prio.next))
rt_rq->highest_prio.next = next_prio(rq);
if (rq->online && rt_rq->highest_prio.curr != prev_prio)
cpupri_set(&rq->rd->cpupri, rq->cpu, rt_rq->highest_prio.curr);
}
#else /* CONFIG_SMP */
static inline
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 */
#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
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;
if (rt_rq->rt_nr_running) {
WARN_ON(prio < prev_prio);
/*
* This may have been our highest task, and therefore
* we may have some recomputation to do
*/
if (prio == prev_prio) {
struct rt_prio_array *array = &rt_rq->active;
rt_rq->highest_prio.curr =
sched_find_first_bit(array->bitmap);
}
} else
rt_rq->highest_prio.curr = MAX_RT_PRIO;
dec_rt_prio_smp(rt_rq, prio, prev_prio);
}
#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 */
#ifdef CONFIG_RT_GROUP_SCHED
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)
{
if (rt_se_boosted(rt_se))
rt_rq->rt_nr_boosted--;
WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted);
}
#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);
}
static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head)
{
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.
* The latter is a consequence of the former when a child group
* get throttled and the current group doesn't have any other
* active members.
*/
if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running))
return;
if (!rt_rq->rt_nr_running)
list_add_leaf_rt_rq(rt_rq);
if (head)
list_add(&rt_se->run_list, queue);
else
list_add_tail(&rt_se->run_list, queue);
__set_bit(rt_se_prio(rt_se), array->bitmap);
inc_rt_tasks(rt_se, rt_rq);
}
static void __dequeue_rt_entity(struct sched_rt_entity *rt_se)
{
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);
if (!rt_rq->rt_nr_running)
list_del_leaf_rt_rq(rt_rq);
}
/*
* Because the prio of an upper entry depends on the lower
* entries, we must remove entries top - down.
*/
static void dequeue_rt_stack(struct sched_rt_entity *rt_se)
{
struct sched_rt_entity *back = NULL;
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))
__dequeue_rt_entity(rt_se);
}
}
static void enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head)
{
dequeue_rt_stack(rt_se);
for_each_sched_rt_entity(rt_se)
__enqueue_rt_entity(rt_se, head);
}
static void dequeue_rt_entity(struct sched_rt_entity *rt_se)
{
dequeue_rt_stack(rt_se);
for_each_sched_rt_entity(rt_se) {
struct rt_rq *rt_rq = group_rt_rq(rt_se);
if (rt_rq && rt_rq->rt_nr_running)
__enqueue_rt_entity(rt_se, false);
}
}
/*
* Adding/removing a task to/from a priority array:
*/
static void
enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)
{
struct sched_rt_entity *rt_se = &p->rt;
if (flags & ENQUEUE_WAKEUP)
rt_se->timeout = 0;
enqueue_rt_entity(rt_se, flags & ENQUEUE_HEAD);
if (!task_current(rq, p) && p->rt.nr_cpus_allowed > 1)
enqueue_pushable_task(rq, p);
}
static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
{
struct sched_rt_entity *rt_se = &p->rt;
update_curr_rt(rq);
dequeue_rt_entity(rt_se);
dequeue_pushable_task(rq, p);
}
/*
* 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, int head)
{
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 (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, 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, head);
}
}
static void yield_task_rt(struct rq *rq)
{
requeue_task_rt(rq, rq->curr, 0);
}
#ifdef CONFIG_SMP
static int find_lowest_rq(struct task_struct *task);
static int
select_task_rq_rt(struct task_struct *p, int sd_flag, int flags)
{
struct task_struct *curr;
struct rq *rq;
int cpu;
if (sd_flag != SD_BALANCE_WAKE)
return smp_processor_id();
cpu = task_cpu(p);
rq = cpu_rq(cpu);
rcu_read_lock();
curr = ACCESS_ONCE(rq->curr); /* unlocked access */
/*
* If the current task on @p's runqueue is an RT task, then
* try to see if we can wake this RT task up on another
* runqueue. Otherwise simply start this RT task
* on its current runqueue.
*
* 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.
*
* 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.
*/
if (curr && unlikely(rt_task(curr)) &&
(curr->rt.nr_cpus_allowed < 2 ||
curr->prio <= p->prio) &&
(p->rt.nr_cpus_allowed > 1)) {
int target = find_lowest_rq(p);
if (target != -1)
cpu = target;
}
rcu_read_unlock();
return cpu;
}
static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
{
if (rq->curr->rt.nr_cpus_allowed == 1)
return;
if (p->rt.nr_cpus_allowed != 1
&& cpupri_find(&rq->rd->cpupri, p, NULL))
return;
if (!cpupri_find(&rq->rd->cpupri, rq->curr, NULL))
return;
/*
* There appears to be other cpus that can accept
* current and none to run 'p', so lets reschedule
* to try and push current away:
*/
requeue_task_rt(rq, p, 1);
resched_task(rq->curr);
}
#endif /* CONFIG_SMP */
/*
* Preempt the current task with a newly woken task if needed:
*/
static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flags)
{
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 && !test_tsk_need_resched(rq->curr))
check_preempt_equal_prio(rq, p);
#endif
}
static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
struct rt_rq *rt_rq)
{
struct rt_prio_array *array = &rt_rq->active;
struct sched_rt_entity *next = NULL;
struct list_head *queue;
int idx;
idx = sched_find_first_bit(array->bitmap);
BUG_ON(idx >= MAX_RT_PRIO);
queue = array->queue + idx;
next = list_entry(queue->next, struct sched_rt_entity, run_list);
return next;
}
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;
rt_rq = &rq->rt;
if (unlikely(!rt_rq->rt_nr_running))
return NULL;
if (rt_rq_throttled(rt_rq))
return NULL;
do {
rt_se = pick_next_rt_entity(rq, rt_rq);
BUG_ON(!rt_se);
rt_rq = group_rt_rq(rt_se);
} while (rt_rq);
p = rt_task_of(rt_se);
p->se.exec_start = rq->clock_task;
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);
#ifdef CONFIG_SMP
/*
* 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);
#endif
return p;
}
static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
{
update_curr_rt(rq);
p->se.exec_start = 0;
/*
* The previous task needs to be made eligible for pushing
* if it is still active
*/
if (on_rt_rq(&p->rt) && p->rt.nr_cpus_allowed > 1)
enqueue_pushable_task(rq, p);
}
#ifdef CONFIG_SMP
/* Only try algorithms three times */
#define RT_MAX_TRIES 3
static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep);
static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
{
if (!task_running(rq, p) &&
(cpu < 0 || cpumask_test_cpu(cpu, &p->cpus_allowed)) &&
(p->rt.nr_cpus_allowed > 1))
return 1;
return 0;
}
/* Return the second highest RT task, NULL otherwise */
static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu)
{
struct task_struct *next = NULL;
struct sched_rt_entity *rt_se;
struct rt_prio_array *array;
struct rt_rq *rt_rq;
int idx;
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;
if (!rt_entity_is_task(rt_se))
continue;
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;
}
}
return next;
}
static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask);
static int find_lowest_rq(struct task_struct *task)
{
struct sched_domain *sd;
struct cpumask *lowest_mask = __get_cpu_var(local_cpu_mask);
int this_cpu = smp_processor_id();
int cpu = task_cpu(task);
/* Make sure the mask is initialized first */
if (unlikely(!lowest_mask))
return -1;
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 */
/*
* 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.
*/
if (cpumask_test_cpu(cpu, lowest_mask))
return cpu;
/*
* Otherwise, we consult the sched_domains span maps to figure
* out which cpu is logically closest to our hot cache data.
*/
if (!cpumask_test_cpu(this_cpu, lowest_mask))
this_cpu = -1; /* Skip this_cpu opt if not among lowest */
rcu_read_lock();
for_each_domain(cpu, sd) {
if (sd->flags & SD_WAKE_AFFINE) {
int best_cpu;
/*
* "this_cpu" is cheaper to preempt than a
* remote processor.
*/
if (this_cpu != -1 &&
cpumask_test_cpu(this_cpu, sched_domain_span(sd))) {
rcu_read_unlock();
return this_cpu;
}
best_cpu = cpumask_first_and(lowest_mask,
sched_domain_span(sd));
if (best_cpu < nr_cpu_ids) {
rcu_read_unlock();
return best_cpu;
}
}
}
rcu_read_unlock();
/*
* And finally, if there were no matches within the domains
* just give the caller *something* to work with from the compatible
* locations.
*/
if (this_cpu != -1)
return this_cpu;
cpu = cpumask_any(lowest_mask);
if (cpu < nr_cpu_ids)
return cpu;
return -1;
}
/* Will lock the rq it finds */
static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
{
struct rq *lowest_rq = NULL;
int tries;
int cpu;
for (tries = 0; tries < RT_MAX_TRIES; tries++) {
cpu = find_lowest_rq(task);
if ((cpu == -1) || (cpu == rq->cpu))
break;
lowest_rq = cpu_rq(cpu);
/* if the prio of this runqueue changed, try again */
if (double_lock_balance(rq, lowest_rq)) {
/*
* 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.
*/
if (unlikely(task_rq(task) != rq ||
!cpumask_test_cpu(lowest_rq->cpu,
&task->cpus_allowed) ||
task_running(rq, task) ||
!task->on_rq)) {
raw_spin_unlock(&lowest_rq->lock);
lowest_rq = NULL;
break;
}
}
/* If this rq is still suitable use it. */
if (lowest_rq->rt.highest_prio.curr > task->prio)
break;
/* try again */
double_unlock_balance(rq, lowest_rq);
lowest_rq = NULL;
}
return lowest_rq;
}
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);
BUG_ON(!p->on_rq);
BUG_ON(!rt_task(p));
return p;
}
/*
* 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.
*/
static int push_rt_task(struct rq *rq)
{
struct task_struct *next_task;
struct rq *lowest_rq;
if (!rq->rt.overloaded)
return 0;
next_task = pick_next_pushable_task(rq);
if (!next_task)
return 0;
retry:
if (unlikely(next_task == rq->curr)) {
WARN_ON(1);
return 0;
}
/*
* It's possible that the next_task slipped in of
* higher priority than current. If that's the case
* just reschedule current.
*/
if (unlikely(next_task->prio < rq->curr->prio)) {
resched_task(rq->curr);
return 0;
}
/* We might release rq lock */
get_task_struct(next_task);
/* find_lock_lowest_rq locks the rq if found */
lowest_rq = find_lock_lowest_rq(next_task, rq);
if (!lowest_rq) {
struct task_struct *task;
/*
* find lock_lowest_rq releases rq->lock
* 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.
*/
task = pick_next_pushable_task(rq);
if (task_cpu(next_task) == rq->cpu && task == next_task) {
/*
* If we get here, the task hasn't moved at all, but
* it has failed to push. We will not try again,
* since the other cpus will pull from us when they
* are ready.
*/
dequeue_pushable_task(rq, next_task);
goto out;
}
if (!task)
/* No more tasks, just exit */
goto out;
/*
* Something has shifted, try again.
*/
put_task_struct(next_task);
next_task = task;
goto retry;
}
deactivate_task(rq, next_task, 0);
set_task_cpu(next_task, lowest_rq->cpu);
activate_task(lowest_rq, next_task, 0);
resched_task(lowest_rq->curr);
double_unlock_balance(rq, lowest_rq);
out:
put_task_struct(next_task);
return 1;
}
static void push_rt_tasks(struct rq *rq)
{
/* push_rt_task will return true if it moved an RT */
while (push_rt_task(rq))
;
}
static int pull_rt_task(struct rq *this_rq)
{
int this_cpu = this_rq->cpu, ret = 0, cpu;
struct task_struct *p;
struct rq *src_rq;
if (likely(!rt_overloaded(this_rq)))
return 0;
for_each_cpu(cpu, this_rq->rd->rto_mask) {
if (this_cpu == cpu)
continue;
src_rq = cpu_rq(cpu);
/*
* 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;
/*
* We can potentially drop this_rq's lock in
* double_lock_balance, and another CPU could
* alter this_rq
*/
double_lock_balance(this_rq, src_rq);
/*
* Are there still pullable RT tasks?
*/
if (src_rq->rt.rt_nr_running <= 1)
goto skip;
p = pick_next_highest_task_rt(src_rq, this_cpu);
/*
* Do we have an RT task that preempts
* the to-be-scheduled task?
*/
if (p && (p->prio < this_rq->rt.highest_prio.curr)) {
WARN_ON(p == src_rq->curr);
WARN_ON(!p->on_rq);
/*
* 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
* current task on the run queue
*/
if (p->prio < src_rq->curr->prio)
goto skip;
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
* in another runqueue. (low likelihood
* but possible)
*/
}
skip:
double_unlock_balance(this_rq, src_rq);
}
return ret;
}
static void pre_schedule_rt(struct rq *rq, struct task_struct *prev)
{
/* Try to pull RT tasks here if we lower this rq's prio */
if (unlikely(rt_task(prev)) && rq->rt.highest_prio.curr > prev->prio)
pull_rt_task(rq);
}
static void post_schedule_rt(struct rq *rq)
{
push_rt_tasks(rq);
}
/*
* If we are not running and we are not going to reschedule soon, we should
* try to push tasks away now
*/
static void task_woken_rt(struct rq *rq, struct task_struct *p)
{
if (!task_running(rq, p) &&
!test_tsk_need_resched(rq->curr) &&
has_pushable_tasks(rq) &&
p->rt.nr_cpus_allowed > 1 &&
rt_task(rq->curr) &&
(rq->curr->rt.nr_cpus_allowed < 2 ||
rq->curr->prio <= p->prio))
push_rt_tasks(rq);
}
static void set_cpus_allowed_rt(struct task_struct *p,
const struct cpumask *new_mask)
{
int weight = cpumask_weight(new_mask);
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.
*/
if (p->on_rq && (weight != p->rt.nr_cpus_allowed)) {
struct rq *rq = task_rq(p);
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);
}
if ((p->rt.nr_cpus_allowed <= 1) && (weight > 1)) {
rq->rt.rt_nr_migratory++;
} else if ((p->rt.nr_cpus_allowed > 1) && (weight <= 1)) {
BUG_ON(!rq->rt.rt_nr_migratory);
rq->rt.rt_nr_migratory--;
}
update_rt_migration(&rq->rt);
}
cpumask_copy(&p->cpus_allowed, new_mask);
p->rt.nr_cpus_allowed = weight;
}
/* Assumes rq->lock is held */
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.curr);
}
/* Assumes rq->lock is held */
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);
}
/*
* When switch from the rt queue, we bring ourselves to a position
* that we might want to pull RT tasks from other runqueues.
*/
static void switched_from_rt(struct rq *rq, struct task_struct *p)
{
/*
* 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.
*/
if (p->on_rq && !rq->rt.rt_nr_running)
pull_rt_task(rq);
}
static inline void init_sched_rt_class(void)
{
unsigned int i;
for_each_possible_cpu(i)
zalloc_cpumask_var_node(&per_cpu(local_cpu_mask, i),
GFP_KERNEL, cpu_to_node(i));
}
#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.
*/
static void switched_to_rt(struct rq *rq, struct task_struct *p)
{
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.
*/
if (p->on_rq && rq->curr != p) {
#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.
*/
static void
prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
{
if (!p->on_rq)
return;
if (rq->curr == p) {
#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
* 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.
*/
if (p->prio > rq->rt.highest_prio.curr && rq->curr == p)
resched_task(p);
#else
/* For UP simply resched on drop of prio */
if (oldprio < p->prio)
resched_task(p);
#endif /* CONFIG_SMP */
} 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);
}
}
static void watchdog(struct rq *rq, struct task_struct *p)
{
unsigned long soft, hard;
/* 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);
if (soft != RLIM_INFINITY) {
unsigned long next;
p->rt.timeout++;
next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ);
if (p->rt.timeout > next)
p->cputime_expires.sched_exp = p->se.sum_exec_runtime;
}
}
static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
{
update_curr_rt(rq);
watchdog(rq, p);
/*
* RR tasks need a special form of timeslice management.
* FIFO tasks have no timeslices.
*/
if (p->policy != SCHED_RR)
return;
if (--p->rt.time_slice)
return;
p->rt.time_slice = DEF_TIMESLICE;
/*
* Requeue to the end of queue if we are not the only element
* on the queue:
*/
if (p->rt.run_list.prev != p->rt.run_list.next) {
requeue_task_rt(rq, p, 0);
set_tsk_need_resched(p);
}
}
static void set_curr_task_rt(struct rq *rq)
{
struct task_struct *p = rq->curr;
p->se.exec_start = rq->clock_task;
/* The running task is never eligible for pushing */
dequeue_pushable_task(rq, p);
}
static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task)
{
/*
* Time slice is 0 for SCHED_FIFO tasks
*/
if (task->policy == SCHED_RR)
return DEF_TIMESLICE;
else
return 0;
}
static const struct sched_class rt_sched_class = {
.next = &fair_sched_class,
.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,
#ifdef CONFIG_SMP
.select_task_rq = select_task_rq_rt,
.set_cpus_allowed = set_cpus_allowed_rt,
.rq_online = rq_online_rt,
.rq_offline = rq_offline_rt,
.pre_schedule = pre_schedule_rt,
.post_schedule = post_schedule_rt,
.task_woken = task_woken_rt,
.switched_from = switched_from_rt,
#endif
.set_curr_task = set_curr_task_rt,
.task_tick = task_tick_rt,
.get_rr_interval = get_rr_interval_rt,
.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)
{
rt_rq_iter_t iter;
struct rt_rq *rt_rq;
rcu_read_lock();
for_each_rt_rq(rt_rq, iter, cpu_rq(cpu))
print_rt_rq(m, cpu, rt_rq);
rcu_read_unlock();
}
#endif /* CONFIG_SCHED_DEBUG */
Jump to Line
Something went wrong with that request. Please try again.