Messages in this thread | | | Date | Thu, 21 Nov 2013 08:26:31 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH 04/14] sched: SCHED_DEADLINE SMP-related data structures & logic. |
| |
On Thu, Nov 21, 2013 at 05:16:50PM +0100, Juri Lelli wrote: > On 11/21/2013 05:08 PM, Paul E. McKenney wrote: > > On Thu, Nov 21, 2013 at 03:13:28PM +0100, Juri Lelli wrote: > >> On 11/20/2013 07:51 PM, Steven Rostedt wrote: > >>> On Thu, 7 Nov 2013 14:43:38 +0100 > >>> Juri Lelli <juri.lelli@gmail.com> wrote: > >>> > >>> > >>>> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > >>>> index cb93f2e..18a73b4 100644 > >>>> --- a/kernel/sched/deadline.c > >>>> +++ b/kernel/sched/deadline.c > >>>> @@ -10,6 +10,7 @@ > >>>> * miss some of their deadlines), and won't affect any other task. > >>>> * > >>>> * Copyright (C) 2012 Dario Faggioli <raistlin@linux.it>, > >>>> + * Juri Lelli <juri.lelli@gmail.com>, > >>>> * Michael Trimarchi <michael@amarulasolutions.com>, > >>>> * Fabio Checconi <fchecconi@gmail.com> > >>>> */ > >>>> @@ -20,6 +21,15 @@ static inline int dl_time_before(u64 a, u64 b) > >>>> return (s64)(a - b) < 0; > >>>> } > >>>> > >>>> +/* > >>>> + * Tells if entity @a should preempt entity @b. > >>>> + */ > >>>> +static inline > >>>> +int dl_entity_preempt(struct sched_dl_entity *a, struct sched_dl_entity *b) > >>>> +{ > >>>> + return dl_time_before(a->deadline, b->deadline); > >>>> +} > >>>> + > >>>> static inline struct task_struct *dl_task_of(struct sched_dl_entity *dl_se) > >>>> { > >>>> return container_of(dl_se, struct task_struct, dl); > >>>> @@ -53,8 +63,168 @@ static inline int is_leftmost(struct task_struct *p, struct dl_rq *dl_rq) > >>>> void init_dl_rq(struct dl_rq *dl_rq, struct rq *rq) > >>>> { > >>>> dl_rq->rb_root = RB_ROOT; > >>>> + > >>>> +#ifdef CONFIG_SMP > >>>> + /* zero means no -deadline tasks */ > >>> > >>> I'm curious to why you add the '-' to -deadline. > >>> > >> > >> I guess "deadline tasks" is too much generic; "SCHED_DEADLINE tasks" too long; > >> "DL" or "-dl" can be associated to "download". Nothing special in the end, just > >> tought it was a reasonable abbreviation. > > > > My guess was that "-deadline" was an abbreviation for tasks that had > > missed their deadline, just so you know. ;-) > > > > Argh! ;) > > Actually, thinking about it twice: if we call "-rt tasks" things that are > governed by code that resides in sched/rt.c, we could agree on "-deadline > tasks" for things that pass through sched/deadline.c.
Actually, "SCHED_DEADLINE" isn't -that- much longer than "-deadline" and it does have the virtue of being unambiguous.
Thanx, Paul
> Thanks, > > - Juri > > >>>> + dl_rq->earliest_dl.curr = dl_rq->earliest_dl.next = 0; > >>>> + > >>>> + dl_rq->dl_nr_migratory = 0; > >>>> + dl_rq->overloaded = 0; > >>>> + dl_rq->pushable_dl_tasks_root = RB_ROOT; > >>>> +#endif > >>>> +} > >>>> + > >>>> +#ifdef CONFIG_SMP > >>>> + > >>>> +static inline int dl_overloaded(struct rq *rq) > >>>> +{ > >>>> + return atomic_read(&rq->rd->dlo_count); > >>>> +} > >>>> + > >>>> +static inline void dl_set_overload(struct rq *rq) > >>>> +{ > >>>> + if (!rq->online) > >>>> + return; > >>>> + > >>>> + cpumask_set_cpu(rq->cpu, rq->rd->dlo_mask); > >>>> + /* > >>>> + * Must be visible before the overload count is > >>>> + * set (as in sched_rt.c). > >>>> + * > >>>> + * Matched by the barrier in pull_dl_task(). > >>>> + */ > >>>> + smp_wmb(); > >>>> + atomic_inc(&rq->rd->dlo_count); > >>>> +} > >>>> + > >>>> +static inline void dl_clear_overload(struct rq *rq) > >>>> +{ > >>>> + if (!rq->online) > >>>> + return; > >>>> + > >>>> + atomic_dec(&rq->rd->dlo_count); > >>>> + cpumask_clear_cpu(rq->cpu, rq->rd->dlo_mask); > >>>> +} > >>>> + > >>>> +static void update_dl_migration(struct dl_rq *dl_rq) > >>>> +{ > >>>> + if (dl_rq->dl_nr_migratory && dl_rq->dl_nr_total > 1) { > >>>> + if (!dl_rq->overloaded) { > >>>> + dl_set_overload(rq_of_dl_rq(dl_rq)); > >>>> + dl_rq->overloaded = 1; > >>>> + } > >>>> + } else if (dl_rq->overloaded) { > >>>> + dl_clear_overload(rq_of_dl_rq(dl_rq)); > >>>> + dl_rq->overloaded = 0; > >>>> + } > >>>> +} > >>>> + > >>>> +static void inc_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) > >>>> +{ > >>>> + struct task_struct *p = dl_task_of(dl_se); > >>>> + dl_rq = &rq_of_dl_rq(dl_rq)->dl; > >>>> + > >>>> + dl_rq->dl_nr_total++; > >>>> + if (p->nr_cpus_allowed > 1) > >>>> + dl_rq->dl_nr_migratory++; > >>>> + > >>>> + update_dl_migration(dl_rq); > >>>> +} > >>>> + > >>>> +static void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) > >>>> +{ > >>>> + struct task_struct *p = dl_task_of(dl_se); > >>>> + dl_rq = &rq_of_dl_rq(dl_rq)->dl; > >>>> + > >>>> + dl_rq->dl_nr_total--; > >>>> + if (p->nr_cpus_allowed > 1) > >>>> + dl_rq->dl_nr_migratory--; > >>>> + > >>>> + update_dl_migration(dl_rq); > >>>> +} > >>>> + > >>>> +/* > >>>> + * The list of pushable -deadline task is not a plist, like in > >>>> + * sched_rt.c, it is an rb-tree with tasks ordered by deadline. > >>>> + */ > >>>> +static void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p) > >>>> +{ > >>>> + struct dl_rq *dl_rq = &rq->dl; > >>>> + struct rb_node **link = &dl_rq->pushable_dl_tasks_root.rb_node; > >>>> + struct rb_node *parent = NULL; > >>>> + struct task_struct *entry; > >>>> + int leftmost = 1; > >>>> + > >>>> + BUG_ON(!RB_EMPTY_NODE(&p->pushable_dl_tasks)); > >>>> + > >>>> + while (*link) { > >>>> + parent = *link; > >>>> + entry = rb_entry(parent, struct task_struct, > >>>> + pushable_dl_tasks); > >>>> + if (dl_entity_preempt(&p->dl, &entry->dl)) > >>>> + link = &parent->rb_left; > >>>> + else { > >>>> + link = &parent->rb_right; > >>>> + leftmost = 0; > >>>> + } > >>>> + } > >>>> + > >>>> + if (leftmost) > >>>> + dl_rq->pushable_dl_tasks_leftmost = &p->pushable_dl_tasks; > >>>> + > >>>> + rb_link_node(&p->pushable_dl_tasks, parent, link); > >>>> + rb_insert_color(&p->pushable_dl_tasks, &dl_rq->pushable_dl_tasks_root); > >>>> +} > >>>> + > >>>> +static void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p) > >>>> +{ > >>>> + struct dl_rq *dl_rq = &rq->dl; > >>>> + > >>>> + if (RB_EMPTY_NODE(&p->pushable_dl_tasks)) > >>>> + return; > >>>> + > >>>> + if (dl_rq->pushable_dl_tasks_leftmost == &p->pushable_dl_tasks) { > >>>> + struct rb_node *next_node; > >>>> + > >>>> + next_node = rb_next(&p->pushable_dl_tasks); > >>>> + dl_rq->pushable_dl_tasks_leftmost = next_node; > >>>> + } > >>>> + > >>>> + rb_erase(&p->pushable_dl_tasks, &dl_rq->pushable_dl_tasks_root); > >>>> + RB_CLEAR_NODE(&p->pushable_dl_tasks); > >>>> +} > >>>> + > >>>> +static inline int has_pushable_dl_tasks(struct rq *rq) > >>>> +{ > >>>> + return !RB_EMPTY_ROOT(&rq->dl.pushable_dl_tasks_root); > >>>> +} > >>>> + > >>>> +static int push_dl_task(struct rq *rq); > >>>> + > >>>> +#else > >>>> + > >>>> +static inline > >>>> +void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p) > >>>> +{ > >>>> +} > >>>> + > >>>> +static inline > >>>> +void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p) > >>>> +{ > >>>> +} > >>>> + > >>>> +static inline > >>>> +void inc_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) > >>>> +{ > >>>> +} > >>>> + > >>>> +static inline > >>>> +void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) > >>>> +{ > >>>> } > >>>> > >>>> +#endif /* CONFIG_SMP */ > >>>> + > >>>> static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags); > >>>> static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags); > >>>> static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p, > >>>> @@ -307,6 +477,14 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer) > >>>> check_preempt_curr_dl(rq, p, 0); > >>>> else > >>>> resched_task(rq->curr); > >>>> +#ifdef CONFIG_SMP > >>>> + /* > >>>> + * Queueing this task back might have overloaded rq, > >>>> + * check if we need to kick someone away. > >>>> + */ > >>>> + if (has_pushable_dl_tasks(rq)) > >>>> + push_dl_task(rq); > >>>> +#endif > >>>> } > >>>> unlock: > >>>> raw_spin_unlock(&rq->lock); > >>>> @@ -397,6 +575,100 @@ static void update_curr_dl(struct rq *rq) > >>>> } > >>>> } > >>>> > >>>> +#ifdef CONFIG_SMP > >>>> + > >>>> +static struct task_struct *pick_next_earliest_dl_task(struct rq *rq, int cpu); > >>>> + > >>>> +static inline u64 next_deadline(struct rq *rq) > >>>> +{ > >>>> + struct task_struct *next = pick_next_earliest_dl_task(rq, rq->cpu); > >>>> + > >>>> + if (next && dl_prio(next->prio)) > >>>> + return next->dl.deadline; > >>>> + else > >>>> + return 0; > >>>> +} > >>>> + > >>>> +static void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline) > >>>> +{ > >>>> + struct rq *rq = rq_of_dl_rq(dl_rq); > >>>> + > >>>> + if (dl_rq->earliest_dl.curr == 0 || > >>>> + dl_time_before(deadline, dl_rq->earliest_dl.curr)) { > >>>> + /* > >>>> + * If the dl_rq had no -deadline tasks, or if the new task > >>>> + * has shorter deadline than the current one on dl_rq, we > >>>> + * know that the previous earliest becomes our next earliest, > >>>> + * as the new task becomes the earliest itself. > >>>> + */ > >>>> + dl_rq->earliest_dl.next = dl_rq->earliest_dl.curr; > >>>> + dl_rq->earliest_dl.curr = deadline; > >>>> + } else if (dl_rq->earliest_dl.next == 0 || > >>>> + dl_time_before(deadline, dl_rq->earliest_dl.next)) { > >>>> + /* > >>>> + * On the other hand, if the new -deadline task has a > >>>> + * a later deadline than the earliest one on dl_rq, but > >>>> + * it is earlier than the next (if any), we must > >>>> + * recompute the next-earliest. > >>>> + */ > >>>> + dl_rq->earliest_dl.next = next_deadline(rq); > >>>> + } > >>>> +} > >>>> + > >>>> +static void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline) > >>>> +{ > >>>> + struct rq *rq = rq_of_dl_rq(dl_rq); > >>>> + > >>>> + /* > >>>> + * Since we may have removed our earliest (and/or next earliest) > >>>> + * task we must recompute them. > >>>> + */ > >>>> + if (!dl_rq->dl_nr_running) { > >>>> + dl_rq->earliest_dl.curr = 0; > >>>> + dl_rq->earliest_dl.next = 0; > >>>> + } else { > >>>> + struct rb_node *leftmost = dl_rq->rb_leftmost; > >>>> + struct sched_dl_entity *entry; > >>>> + > >>>> + entry = rb_entry(leftmost, struct sched_dl_entity, rb_node); > >>>> + dl_rq->earliest_dl.curr = entry->deadline; > >>>> + dl_rq->earliest_dl.next = next_deadline(rq); > >>>> + } > >>>> +} > >>>> + > >>>> +#else > >>>> + > >>>> +static inline void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline) {} > >>>> +static inline void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline) {} > >>>> + > >>>> +#endif /* CONFIG_SMP */ > >>>> + > >>>> +static inline > >>>> +void inc_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) > >>>> +{ > >>>> + int prio = dl_task_of(dl_se)->prio; > >>>> + u64 deadline = dl_se->deadline; > >>>> + > >>>> + WARN_ON(!dl_prio(prio)); > >>>> + dl_rq->dl_nr_running++; > >>>> + > >>>> + inc_dl_deadline(dl_rq, deadline); > >>>> + inc_dl_migration(dl_se, dl_rq); > >>>> +} > >>>> + > >>>> +static inline > >>>> +void dec_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) > >>>> +{ > >>>> + int prio = dl_task_of(dl_se)->prio; > >>>> + > >>>> + WARN_ON(!dl_prio(prio)); > >>>> + WARN_ON(!dl_rq->dl_nr_running); > >>>> + dl_rq->dl_nr_running--; > >>>> + > >>>> + dec_dl_deadline(dl_rq, dl_se->deadline); > >>>> + dec_dl_migration(dl_se, dl_rq); > >>>> +} > >>>> + > >>>> static void __enqueue_dl_entity(struct sched_dl_entity *dl_se) > >>>> { > >>>> struct dl_rq *dl_rq = dl_rq_of_se(dl_se); > >>>> @@ -424,7 +696,7 @@ static void __enqueue_dl_entity(struct sched_dl_entity *dl_se) > >>>> rb_link_node(&dl_se->rb_node, parent, link); > >>>> rb_insert_color(&dl_se->rb_node, &dl_rq->rb_root); > >>>> > >>>> - dl_rq->dl_nr_running++; > >>>> + inc_dl_tasks(dl_se, dl_rq); > >>>> } > >>>> > >>>> static void __dequeue_dl_entity(struct sched_dl_entity *dl_se) > >>>> @@ -444,7 +716,7 @@ static void __dequeue_dl_entity(struct sched_dl_entity *dl_se) > >>>> rb_erase(&dl_se->rb_node, &dl_rq->rb_root); > >>>> RB_CLEAR_NODE(&dl_se->rb_node); > >>>> > >>>> - dl_rq->dl_nr_running--; > >>>> + dec_dl_tasks(dl_se, dl_rq); > >>>> } > >>>> > >>>> static void > >>>> @@ -482,12 +754,17 @@ static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags) > >>>> return; > >>>> > >>>> enqueue_dl_entity(&p->dl, flags); > >>>> + > >>>> + if (!task_current(rq, p) && p->nr_cpus_allowed > 1) > >>>> + enqueue_pushable_dl_task(rq, p); > >>>> + > >>>> inc_nr_running(rq); > >>>> } > >>>> > >>>> static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags) > >>>> { > >>>> dequeue_dl_entity(&p->dl); > >>>> + dequeue_pushable_dl_task(rq, p); > >>>> } > >>>> > >>>> static void dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags) > >>>> @@ -525,6 +802,77 @@ static void yield_task_dl(struct rq *rq) > >>>> update_curr_dl(rq); > >>>> } > >>>> > >>>> +#ifdef CONFIG_SMP > >>>> + > >>>> +static int find_later_rq(struct task_struct *task); > >>>> +static int latest_cpu_find(struct cpumask *span, > >>>> + struct task_struct *task, > >>>> + struct cpumask *later_mask); > >>>> + > >>>> +static int > >>>> +select_task_rq_dl(struct task_struct *p, int sd_flag, int flags) > >>>> +{ > >>>> + struct task_struct *curr; > >>>> + struct rq *rq; > >>>> + int cpu; > >>>> + > >>>> + cpu = task_cpu(p); > >>>> + > >>>> + if (sd_flag != SD_BALANCE_WAKE && sd_flag != SD_BALANCE_FORK) > >>>> + goto out; > >>>> + > >>>> + rq = cpu_rq(cpu); > >>>> + > >>>> + rcu_read_lock(); > >>>> + curr = ACCESS_ONCE(rq->curr); /* unlocked access */ > >>>> + > >>>> + /* > >>>> + * If we are dealing with a -deadline task, we must > >>>> + * decide where to wake it up. > >>>> + * If it has a later deadline and the current task > >>>> + * on this rq can't move (provided the waking task > >>>> + * can!) we prefer to send it somewhere else. On the > >>>> + * other hand, if it has a shorter deadline, we > >>>> + * try to make it stay here, it might be important. > >>>> + */ > >>>> + if (unlikely(dl_task(curr)) && > >>>> + (curr->nr_cpus_allowed < 2 || > >>>> + !dl_entity_preempt(&p->dl, &curr->dl)) && > >>>> + (p->nr_cpus_allowed > 1)) { > >>>> + int target = find_later_rq(p); > >>>> + > >>>> + if (target != -1) > >>>> + cpu = target; > >>>> + } > >>>> + rcu_read_unlock(); > >>>> + > >>>> +out: > >>>> + return cpu; > >>>> +} > >>>> + > >>>> +static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p) > >>>> +{ > >>>> + /* > >>>> + * Current can't be migrated, useless to reschedule, > >>>> + * let's hope p can move out. > >>>> + */ > >>>> + if (rq->curr->nr_cpus_allowed == 1 || > >>>> + latest_cpu_find(rq->rd->span, rq->curr, NULL) == -1) > >>>> + return; > >>>> + > >>>> + /* > >>>> + * p is migratable, so let's not schedule it and > >>>> + * see if it is pushed or pulled somewhere else. > >>>> + */ > >>>> + if (p->nr_cpus_allowed != 1 && > >>>> + latest_cpu_find(rq->rd->span, p, NULL) != -1) > >>>> + return; > >>>> + > >>>> + resched_task(rq->curr); > >>>> +} > >>>> + > >>>> +#endif /* CONFIG_SMP */ > >>>> + > >>>> /* > >>>> * Only called when both the current and waking task are -deadline > >>>> * tasks. > >>>> @@ -532,8 +880,20 @@ static void yield_task_dl(struct rq *rq) > >>>> static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p, > >>>> int flags) > >>>> { > >>>> - if (dl_time_before(p->dl.deadline, rq->curr->dl.deadline)) > >>>> + if (dl_entity_preempt(&p->dl, &rq->curr->dl)) { > >>>> resched_task(rq->curr); > >>>> + return; > >>>> + } > >>>> + > >>>> +#ifdef CONFIG_SMP > >>>> + /* > >>>> + * In the unlikely case current and p have the same deadline > >>>> + * let us try to decide what's the best thing to do... > >>>> + */ > >>>> + if ((s64)(p->dl.deadline - rq->curr->dl.deadline) == 0 && > >>>> + !need_resched()) > >>>> + check_preempt_equal_dl(rq, p); > >>>> +#endif /* CONFIG_SMP */ > >>>> } > >>>> > >>>> #ifdef CONFIG_SCHED_HRTICK > >>>> @@ -573,16 +933,29 @@ struct task_struct *pick_next_task_dl(struct rq *rq) > >>>> > >>>> p = dl_task_of(dl_se); > >>>> p->se.exec_start = rq_clock_task(rq); > >>>> + > >>>> + /* Running task will never be pushed. */ > >>>> + if (p) > >>>> + dequeue_pushable_dl_task(rq, p); > >>>> + > >>>> #ifdef CONFIG_SCHED_HRTICK > >>>> if (hrtick_enabled(rq)) > >>>> start_hrtick_dl(rq, p); > >>>> #endif > >>>> + > >>>> +#ifdef CONFIG_SMP > >>>> + rq->post_schedule = has_pushable_dl_tasks(rq); > >>>> +#endif /* CONFIG_SMP */ > >>>> + > >>>> return p; > >>>> } > >>>> > >>>> static void put_prev_task_dl(struct rq *rq, struct task_struct *p) > >>>> { > >>>> update_curr_dl(rq); > >>>> + > >>>> + if (on_dl_rq(&p->dl) && p->nr_cpus_allowed > 1) > >>>> + enqueue_pushable_dl_task(rq, p); > >>>> } > >>>> > >>>> static void task_tick_dl(struct rq *rq, struct task_struct *p, int queued) > >>>> @@ -616,16 +989,517 @@ static void set_curr_task_dl(struct rq *rq) > >>>> struct task_struct *p = rq->curr; > >>>> > >>>> p->se.exec_start = rq_clock_task(rq); > >>>> + > >>>> + /* You can't push away the running task */ > >>>> + dequeue_pushable_dl_task(rq, p); > >>>> +} > >>>> + > >>>> +#ifdef CONFIG_SMP > >>>> + > >>>> +/* Only try algorithms three times */ > >>>> +#define DL_MAX_TRIES 3 > >>>> + > >>>> +static int pick_dl_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->nr_cpus_allowed > 1)) > >>>> + return 1; > >>>> + > >>>> + return 0; > >>>> +} > >>>> + > >>>> +/* Returns the second earliest -deadline task, NULL otherwise */ > >>>> +static struct task_struct *pick_next_earliest_dl_task(struct rq *rq, int cpu) > >>>> +{ > >>>> + struct rb_node *next_node = rq->dl.rb_leftmost; > >>>> + struct sched_dl_entity *dl_se; > >>>> + struct task_struct *p = NULL; > >>>> + > >>>> +next_node: > >>>> + next_node = rb_next(next_node); > >>>> + if (next_node) { > >>>> + dl_se = rb_entry(next_node, struct sched_dl_entity, rb_node); > >>>> + p = dl_task_of(dl_se); > >>>> + > >>>> + if (pick_dl_task(rq, p, cpu)) > >>>> + return p; > >>>> + > >>>> + goto next_node; > >>>> + } > >>>> + > >>>> + return NULL; > >>>> +} > >>>> + > >>>> +static int latest_cpu_find(struct cpumask *span, > >>>> + struct task_struct *task, > >>>> + struct cpumask *later_mask) > >>>> +{ > >>>> + const struct sched_dl_entity *dl_se = &task->dl; > >>>> + int cpu, found = -1, best = 0; > >>>> + u64 max_dl = 0; > >>>> + > >>>> + for_each_cpu(cpu, span) { > >>>> + struct rq *rq = cpu_rq(cpu); > >>>> + struct dl_rq *dl_rq = &rq->dl; > >>>> + > >>>> + if (cpumask_test_cpu(cpu, &task->cpus_allowed) && > >>>> + (!dl_rq->dl_nr_running || dl_time_before(dl_se->deadline, > >>>> + dl_rq->earliest_dl.curr))) { > >>>> + if (later_mask) > >>>> + cpumask_set_cpu(cpu, later_mask); > >>>> + if (!best && !dl_rq->dl_nr_running) { > >>>> + best = 1; > >>>> + found = cpu; > >>>> + } else if (!best && > >>>> + dl_time_before(max_dl, > >>>> + dl_rq->earliest_dl.curr)) { > >>> > >>> Ug, the above is hard to read. What about: > >>> > >>> if (!best) { > >>> if (!dl_rq->dl_nr_running) { > >>> best = 1; > >>> found = cpu; > >>> } elsif (dl_time_before(...)) { > >>> ... > >>> } > >>> } > >>> > >> > >> This is completely removed in 13/14. I don't like it either, but since we end > >> up removing this mess, do you think we still have to fix this here? > >> > >>> Also, I would think dl should be nice to rt as well. There may be a > >>> idle CPU or a non rt task, and this could pick a CPU running an RT > >>> task. Worse yet, that RT task may be pinned to that CPU. > >>> > >> > >> Well, in 13/14 we introduce a free_cpus mask. A CPU is considered free if it > >> doesn't have any -deadline task running. We can modify that excluding also CPUs > >> running RT tasks, but I have to think a bit if we can do this also from -rt code. > >> > >>> We should be able to incorporate cpuprio_find() to be dl aware too. > >>> That is, work for both -rt and -dl. > >>> > >> > >> Like checking if a -dl task is running on the cpu chosen for pushing an -rt > >> task, and continue searching in that case. > >> > >>> > >>> > >>>> + max_dl = dl_rq->earliest_dl.curr; > >>>> + found = cpu; > >>>> + } > >>>> + } else if (later_mask) > >>>> + cpumask_clear_cpu(cpu, later_mask); > >>>> + } > >>>> + > >>>> + return found; > >>>> +} > >>>> + > >>>> +static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl); > >>>> + > >>>> +static int find_later_rq(struct task_struct *task) > >>>> +{ > >>>> + struct sched_domain *sd; > >>>> + struct cpumask *later_mask = __get_cpu_var(local_cpu_mask_dl); > >>>> + int this_cpu = smp_processor_id(); > >>>> + int best_cpu, cpu = task_cpu(task); > >>>> + > >>>> + /* Make sure the mask is initialized first */ > >>>> + if (unlikely(!later_mask)) > >>>> + return -1; > >>>> + > >>>> + if (task->nr_cpus_allowed == 1) > >>>> + return -1; > >>>> + > >>>> + best_cpu = latest_cpu_find(task_rq(task)->rd->span, task, later_mask); > >>>> + if (best_cpu == -1) > >>>> + return -1; > >>>> + > >>>> + /* > >>>> + * If we are here, some target has been found, > >>>> + * the most suitable of which is cached in best_cpu. > >>>> + * This is, among the runqueues where the current tasks > >>>> + * have later deadlines than the task's one, the rq > >>>> + * with the latest possible one. > >>>> + * > >>>> + * Now we check how well this matches with task's > >>>> + * affinity and system topology. > >>>> + * > >>>> + * The last cpu where the task run is our first > >>>> + * guess, since it is most likely cache-hot there. > >>>> + */ > >>>> + if (cpumask_test_cpu(cpu, later_mask)) > >>>> + return cpu; > >>>> + /* > >>>> + * Check if this_cpu is to be skipped (i.e., it is > >>>> + * not in the mask) or not. > >>>> + */ > >>>> + if (!cpumask_test_cpu(this_cpu, later_mask)) > >>>> + this_cpu = -1; > >>>> + > >>>> + rcu_read_lock(); > >>>> + for_each_domain(cpu, sd) { > >>>> + if (sd->flags & SD_WAKE_AFFINE) { > >>>> + > >>>> + /* > >>>> + * If possible, preempting this_cpu is > >>>> + * cheaper than migrating. > >>>> + */ > >>>> + if (this_cpu != -1 && > >>>> + cpumask_test_cpu(this_cpu, sched_domain_span(sd))) { > >>>> + rcu_read_unlock(); > >>>> + return this_cpu; > >>>> + } > >>>> + > >>>> + /* > >>>> + * Last chance: if best_cpu is valid and is > >>>> + * in the mask, that becomes our choice. > >>>> + */ > >>>> + if (best_cpu < nr_cpu_ids && > >>>> + cpumask_test_cpu(best_cpu, sched_domain_span(sd))) { > >>>> + rcu_read_unlock(); > >>>> + return best_cpu; > >>>> + } > >>>> + } > >>>> + } > >>>> + rcu_read_unlock(); > >>>> + > >>>> + /* > >>>> + * At this point, all our guesses failed, we just return > >>>> + * 'something', and let the caller sort the things out. > >>>> + */ > >>>> + if (this_cpu != -1) > >>>> + return this_cpu; > >>>> + > >>>> + cpu = cpumask_any(later_mask); > >>>> + if (cpu < nr_cpu_ids) > >>>> + return cpu; > >>>> + > >>>> + return -1; > >>>> +} > >>>> + > >>>> +/* Locks the rq it finds */ > >>>> +static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq) > >>>> +{ > >>>> + struct rq *later_rq = NULL; > >>>> + int tries; > >>>> + int cpu; > >>>> + > >>>> + for (tries = 0; tries < DL_MAX_TRIES; tries++) { > >>>> + cpu = find_later_rq(task); > >>>> + > >>>> + if ((cpu == -1) || (cpu == rq->cpu)) > >>>> + break; > >>>> + > >>>> + later_rq = cpu_rq(cpu); > >>>> + > >>>> + /* Retry if something changed. */ > >>>> + if (double_lock_balance(rq, later_rq)) { > >>>> + if (unlikely(task_rq(task) != rq || > >>>> + !cpumask_test_cpu(later_rq->cpu, > >>>> + &task->cpus_allowed) || > >>>> + task_running(rq, task) || !task->on_rq)) { > >>>> + double_unlock_balance(rq, later_rq); > >>>> + later_rq = NULL; > >>>> + break; > >>>> + } > >>>> + } > >>>> + > >>>> + /* > >>>> + * If the rq we found has no -deadline task, or > >>>> + * its earliest one has a later deadline than our > >>>> + * task, the rq is a good one. > >>>> + */ > >>>> + if (!later_rq->dl.dl_nr_running || > >>>> + dl_time_before(task->dl.deadline, > >>>> + later_rq->dl.earliest_dl.curr)) > >>>> + break; > >>>> + > >>>> + /* Otherwise we try again. */ > >>>> + double_unlock_balance(rq, later_rq); > >>>> + later_rq = NULL; > >>>> + } > >>>> + > >>>> + return later_rq; > >>>> } > >>>> > >>>> +static struct task_struct *pick_next_pushable_dl_task(struct rq *rq) > >>>> +{ > >>>> + struct task_struct *p; > >>>> + > >>>> + if (!has_pushable_dl_tasks(rq)) > >>>> + return NULL; > >>>> + > >>>> + p = rb_entry(rq->dl.pushable_dl_tasks_leftmost, > >>>> + struct task_struct, pushable_dl_tasks); > >>>> + > >>>> + BUG_ON(rq->cpu != task_cpu(p)); > >>>> + BUG_ON(task_current(rq, p)); > >>>> + BUG_ON(p->nr_cpus_allowed <= 1); > >>>> + > >>>> + BUG_ON(!p->se.on_rq); > >>>> + BUG_ON(!dl_task(p)); > >>>> + > >>>> + return p; > >>>> +} > >>>> + > >>>> +/* > >>>> + * See if the non running -deadline tasks on this rq > >>>> + * can be sent to some other CPU where they can preempt > >>>> + * and start executing. > >>>> + */ > >>>> +static int push_dl_task(struct rq *rq) > >>>> +{ > >>>> + struct task_struct *next_task; > >>>> + struct rq *later_rq; > >>>> + > >>>> + if (!rq->dl.overloaded) > >>>> + return 0; > >>>> + > >>>> + next_task = pick_next_pushable_dl_task(rq); > >>>> + if (!next_task) > >>>> + return 0; > >>>> + > >>>> +retry: > >>>> + if (unlikely(next_task == rq->curr)) { > >>>> + WARN_ON(1); > >>>> + return 0; > >>>> + } > >>>> + > >>>> + /* > >>>> + * If next_task preempts rq->curr, and rq->curr > >>>> + * can move away, it makes sense to just reschedule > >>>> + * without going further in pushing next_task. > >>>> + */ > >>>> + if (dl_task(rq->curr) && > >>>> + dl_time_before(next_task->dl.deadline, rq->curr->dl.deadline) && > >>>> + rq->curr->nr_cpus_allowed > 1) { > >>>> + resched_task(rq->curr); > >>>> + return 0; > >>>> + } > >>>> + > >>>> + /* We might release rq lock */ > >>>> + get_task_struct(next_task); > >>>> + > >>>> + /* Will lock the rq it'll find */ > >>>> + later_rq = find_lock_later_rq(next_task, rq); > >>>> + if (!later_rq) { > >>>> + struct task_struct *task; > >>>> + > >>>> + /* > >>>> + * We must check all this again, since > >>>> + * find_lock_later_rq releases rq->lock and it is > >>>> + * then possible that next_task has migrated. > >>>> + */ > >>>> + task = pick_next_pushable_dl_task(rq); > >>>> + if (task_cpu(next_task) == rq->cpu && task == next_task) { > >>>> + /* > >>>> + * The task is still there. We don't try > >>>> + * again, some other cpu will pull it when ready. > >>>> + */ > >>>> + dequeue_pushable_dl_task(rq, next_task); > >>>> + goto out; > >>>> + } > >>>> + > >>>> + if (!task) > >>>> + /* No more tasks */ > >>>> + goto out; > >>>> + > >>>> + put_task_struct(next_task); > >>>> + next_task = task; > >>>> + goto retry; > >>>> + } > >>>> + > >>>> + deactivate_task(rq, next_task, 0); > >>>> + set_task_cpu(next_task, later_rq->cpu); > >>>> + activate_task(later_rq, next_task, 0); > >>>> + > >>>> + resched_task(later_rq->curr); > >>>> + > >>>> + double_unlock_balance(rq, later_rq); > >>>> + > >>>> +out: > >>>> + put_task_struct(next_task); > >>>> + > >>>> + return 1; > >>>> +} > >>>> + > >>>> +static void push_dl_tasks(struct rq *rq) > >>>> +{ > >>>> + /* Terminates as it moves a -deadline task */ > >>>> + while (push_dl_task(rq)) > >>>> + ; > >>>> +} > >>>> + > >>>> +static int pull_dl_task(struct rq *this_rq) > >>>> +{ > >>>> + int this_cpu = this_rq->cpu, ret = 0, cpu; > >>>> + struct task_struct *p; > >>>> + struct rq *src_rq; > >>>> + u64 dmin = LONG_MAX; > >>>> + > >>>> + if (likely(!dl_overloaded(this_rq))) > >>>> + return 0; > >>>> + > >>>> + /* > >>>> + * Match the barrier from dl_set_overloaded; this guarantees that if we > >>>> + * see overloaded we must also see the dlo_mask bit. > >>>> + */ > >>>> + smp_rmb(); > >>>> + > >>>> + for_each_cpu(cpu, this_rq->rd->dlo_mask) { > >>>> + if (this_cpu == cpu) > >>>> + continue; > >>>> + > >>>> + src_rq = cpu_rq(cpu); > >>>> + > >>>> + /* > >>>> + * It looks racy, abd it is! However, as in sched_rt.c, > >>> > >>> abd it is? > >>> > >> > >> Oops! > >> > >> Thanks, > >> > >> - Juri > >> > >>> > >>>> + * we are fine with this. > >>>> + */ > >>>> + if (this_rq->dl.dl_nr_running && > >>>> + dl_time_before(this_rq->dl.earliest_dl.curr, > >>>> + src_rq->dl.earliest_dl.next)) > >>>> + continue; > >>>> + > >>>> + /* Might drop this_rq->lock */ > >>>> + double_lock_balance(this_rq, src_rq); > >>>> + > >>>> + /* > >>>> + * If there are no more pullable tasks on the > >>>> + * rq, we're done with it. > >>>> + */ > >>>> + if (src_rq->dl.dl_nr_running <= 1) > >>>> + goto skip; > >>>> + > >>>> + p = pick_next_earliest_dl_task(src_rq, this_cpu); > >>>> + > >>>> + /* > >>>> + * We found a task to be pulled if: > >>>> + * - it preempts our current (if there's one), > >>>> + * - it will preempt the last one we pulled (if any). > >>>> + */ > >>>> + if (p && dl_time_before(p->dl.deadline, dmin) && > >>>> + (!this_rq->dl.dl_nr_running || > >>>> + dl_time_before(p->dl.deadline, > >>>> + this_rq->dl.earliest_dl.curr))) { > >>>> + WARN_ON(p == src_rq->curr); > >>>> + WARN_ON(!p->se.on_rq); > >>>> + > >>>> + /* > >>>> + * Then we pull iff p has actually an earlier > >>>> + * deadline than the current task of its runqueue. > >>>> + */ > >>>> + if (dl_time_before(p->dl.deadline, > >>>> + src_rq->curr->dl.deadline)) > >>>> + goto skip; > >>>> + > >>>> + ret = 1; > >>>> + > >>>> + deactivate_task(src_rq, p, 0); > >>>> + set_task_cpu(p, this_cpu); > >>>> + activate_task(this_rq, p, 0); > >>>> + dmin = p->dl.deadline; > >>>> + > >>>> + /* Is there any other task even earlier? */ > >>>> + } > >>>> +skip: > >>>> + double_unlock_balance(this_rq, src_rq); > >>>> + } > >>>> + > >>>> + return ret; > >>>> +} > >>>> + > >>>> +static void pre_schedule_dl(struct rq *rq, struct task_struct *prev) > >>>> +{ > >>>> + /* Try to pull other tasks here */ > >>>> + if (dl_task(prev)) > >>>> + pull_dl_task(rq); > >>>> +} > >>>> + > >>>> +static void post_schedule_dl(struct rq *rq) > >>>> +{ > >>>> + push_dl_tasks(rq); > >>>> +} > >>>> + > >>>> +/* > >>>> + * Since the task is not running and a reschedule is not going to happen > >>>> + * anytime soon on its runqueue, we try pushing it away now. > >>>> + */ > >>>> +static void task_woken_dl(struct rq *rq, struct task_struct *p) > >>>> +{ > >>>> + if (!task_running(rq, p) && > >>>> + !test_tsk_need_resched(rq->curr) && > >>>> + has_pushable_dl_tasks(rq) && > >>>> + p->nr_cpus_allowed > 1 && > >>>> + dl_task(rq->curr) && > >>>> + (rq->curr->nr_cpus_allowed < 2 || > >>>> + dl_entity_preempt(&rq->curr->dl, &p->dl))) { > >>>> + push_dl_tasks(rq); > >>>> + } > >>>> +} > >>>> + > >>>> +static void set_cpus_allowed_dl(struct task_struct *p, > >>>> + const struct cpumask *new_mask) > >>>> +{ > >>>> + struct rq *rq; > >>>> + int weight; > >>>> + > >>>> + BUG_ON(!dl_task(p)); > >>>> + > >>>> + /* > >>>> + * Update only if the task is actually running (i.e., > >>>> + * it is on the rq AND it is not throttled). > >>>> + */ > >>>> + if (!on_dl_rq(&p->dl)) > >>>> + return; > >>>> + > >>>> + weight = cpumask_weight(new_mask); > >>>> + > >>>> + /* > >>>> + * Only update if the process changes its state from whether it > >>>> + * can migrate or not. > >>>> + */ > >>>> + if ((p->nr_cpus_allowed > 1) == (weight > 1)) > >>>> + return; > >>>> + > >>>> + rq = task_rq(p); > >>>> + > >>>> + /* > >>>> + * The process used to be able to migrate OR it can now migrate > >>>> + */ > >>>> + if (weight <= 1) { > >>>> + if (!task_current(rq, p)) > >>>> + dequeue_pushable_dl_task(rq, p); > >>>> + BUG_ON(!rq->dl.dl_nr_migratory); > >>>> + rq->dl.dl_nr_migratory--; > >>>> + } else { > >>>> + if (!task_current(rq, p)) > >>>> + enqueue_pushable_dl_task(rq, p); > >>>> + rq->dl.dl_nr_migratory++; > >>>> + } > >>>> + > >>>> + update_dl_migration(&rq->dl); > >>>> +} > >>>> + > >>>> +/* Assumes rq->lock is held */ > >>>> +static void rq_online_dl(struct rq *rq) > >>>> +{ > >>>> + if (rq->dl.overloaded) > >>>> + dl_set_overload(rq); > >>>> +} > >>>> + > >>>> +/* Assumes rq->lock is held */ > >>>> +static void rq_offline_dl(struct rq *rq) > >>>> +{ > >>>> + if (rq->dl.overloaded) > >>>> + dl_clear_overload(rq); > >>>> +} > >>>> + > >>>> +void init_sched_dl_class(void) > >>>> +{ > >>>> + unsigned int i; > >>>> + > >>>> + for_each_possible_cpu(i) > >>>> + zalloc_cpumask_var_node(&per_cpu(local_cpu_mask_dl, i), > >>>> + GFP_KERNEL, cpu_to_node(i)); > >>>> +} > >>>> + > >>>> +#endif /* CONFIG_SMP */ > >>>> + > >>>> static void switched_from_dl(struct rq *rq, struct task_struct *p) > >>>> { > >>>> - if (hrtimer_active(&p->dl.dl_timer)) > >>>> + if (hrtimer_active(&p->dl.dl_timer) && !dl_policy(p->policy)) > >>>> hrtimer_try_to_cancel(&p->dl.dl_timer); > >>>> + > >>>> +#ifdef CONFIG_SMP > >>>> + /* > >>>> + * Since this might be the only -deadline task on the rq, > >>>> + * this is the right place to try to pull some other one > >>>> + * from an overloaded cpu, if any. > >>>> + */ > >>>> + if (!rq->dl.dl_nr_running) > >>>> + pull_dl_task(rq); > >>>> +#endif > >>>> } > >>>> > >>>> +/* > >>>> + * When switching to -deadline, we may overload the rq, then > >>>> + * we try to push someone off, if possible. > >>>> + */ > >>>> static void switched_to_dl(struct rq *rq, struct task_struct *p) > >>>> { > >>>> + int check_resched = 1; > >>>> + > >>>> /* > >>>> * If p is throttled, don't consider the possibility > >>>> * of preempting rq->curr, the check will be done right > >>>> @@ -635,26 +1509,53 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p) > >>>> return; > >>>> > >>>> if (!p->on_rq || rq->curr != p) { > >>>> - if (task_has_dl_policy(rq->curr)) > >>>> +#ifdef CONFIG_SMP > >>>> + if (rq->dl.overloaded && push_dl_task(rq) && rq != task_rq(p)) > >>>> + /* Only reschedule if pushing failed */ > >>>> + check_resched = 0; > >>>> +#endif /* CONFIG_SMP */ > >>>> + if (check_resched && task_has_dl_policy(rq->curr)) > >>>> check_preempt_curr_dl(rq, p, 0); > >>>> - else > >>>> - resched_task(rq->curr); > >>>> } > >>>> } > >>>> > >>>> +/* > >>>> + * If the scheduling parameters of a -deadline task changed, > >>>> + * a push or pull operation might be needed. > >>>> + */ > >>>> static void prio_changed_dl(struct rq *rq, struct task_struct *p, > >>>> int oldprio) > >>>> { > >>>> - switched_to_dl(rq, p); > >>>> -} > >>>> - > >>>> + if (p->on_rq || rq->curr == p) { > >>>> #ifdef CONFIG_SMP > >>>> -static int > >>>> -select_task_rq_dl(struct task_struct *p, int sd_flag, int flags) > >>>> -{ > >>>> - return task_cpu(p); > >>>> + /* > >>>> + * This might be too much, but unfortunately > >>>> + * we don't have the old deadline value, and > >>>> + * we can't argue if the task is increasing > >>>> + * or lowering its prio, so... > >>>> + */ > >>>> + if (!rq->dl.overloaded) > >>>> + pull_dl_task(rq); > >>>> + > >>>> + /* > >>>> + * If we now have a earlier deadline task than p, > >>>> + * then reschedule, provided p is still on this > >>>> + * runqueue. > >>>> + */ > >>>> + if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline) && > >>>> + rq->curr == p) > >>>> + resched_task(p); > >>>> +#else > >>>> + /* > >>>> + * Again, we don't know if p has a earlier > >>>> + * or later deadline, so let's blindly set a > >>>> + * (maybe not needed) rescheduling point. > >>>> + */ > >>>> + resched_task(p); > >>>> +#endif /* CONFIG_SMP */ > >>>> + } else > >>>> + switched_to_dl(rq, p); > >>>> } > >>>> -#endif > >>>> > >>>> const struct sched_class dl_sched_class = { > >>>> .next = &rt_sched_class, > >>>> @@ -669,6 +1570,12 @@ const struct sched_class dl_sched_class = { > >>>> > >>>> #ifdef CONFIG_SMP > >>>> .select_task_rq = select_task_rq_dl, > >>>> + .set_cpus_allowed = set_cpus_allowed_dl, > >>>> + .rq_online = rq_online_dl, > >>>> + .rq_offline = rq_offline_dl, > >>>> + .pre_schedule = pre_schedule_dl, > >>>> + .post_schedule = post_schedule_dl, > >>>> + .task_woken = task_woken_dl, > >>>> #endif > >>>> > >>>> .set_curr_task = set_curr_task_dl, > >>>> diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c > >>>> index 01970c8..f7c4881 100644 > >>>> --- a/kernel/sched/rt.c > >>>> +++ b/kernel/sched/rt.c > >>>> @@ -1720,7 +1720,7 @@ static void task_woken_rt(struct rq *rq, struct task_struct *p) > >>>> !test_tsk_need_resched(rq->curr) && > >>>> has_pushable_tasks(rq) && > >>>> p->nr_cpus_allowed > 1 && > >>>> - rt_task(rq->curr) && > >>>> + (dl_task(rq->curr) || rt_task(rq->curr)) && > >>>> (rq->curr->nr_cpus_allowed < 2 || > >>>> rq->curr->prio <= p->prio)) > >>>> push_rt_tasks(rq); > >>>> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > >>>> index ba97476..70d0030 100644 > >>>> --- a/kernel/sched/sched.h > >>>> +++ b/kernel/sched/sched.h > >>>> @@ -383,6 +383,31 @@ struct dl_rq { > >>>> struct rb_node *rb_leftmost; > >>>> > >>>> unsigned long dl_nr_running; > >>>> + > >>>> +#ifdef CONFIG_SMP > >>>> + /* > >>>> + * Deadline values of the currently executing and the > >>>> + * earliest ready task on this rq. Caching these facilitates > >>>> + * the decision wether or not a ready but not running task > >>>> + * should migrate somewhere else. > >>>> + */ > >>>> + struct { > >>>> + u64 curr; > >>>> + u64 next; > >>>> + } earliest_dl; > >>>> + > >>>> + unsigned long dl_nr_migratory; > >>>> + unsigned long dl_nr_total; > >>>> + int overloaded; > >>>> + > >>>> + /* > >>>> + * Tasks on this rq that can be pushed away. They are kept in > >>>> + * an rb-tree, ordered by tasks' deadlines, with caching > >>>> + * of the leftmost (earliest deadline) element. > >>>> + */ > >>>> + struct rb_root pushable_dl_tasks_root; > >>>> + struct rb_node *pushable_dl_tasks_leftmost; > >>>> +#endif > >>>> }; > >>>> > >>>> #ifdef CONFIG_SMP > >>>> @@ -403,6 +428,13 @@ struct root_domain { > >>>> cpumask_var_t online; > >>>> > >>>> /* > >>>> + * The bit corresponding to a CPU gets set here if such CPU has more > >>>> + * than one runnable -deadline task (as it is below for RT tasks). > >>>> + */ > >>>> + cpumask_var_t dlo_mask; > >>>> + atomic_t dlo_count; > >>>> + > >>>> + /* > >>>> * The "RT overload" flag: it gets set if a CPU has more than > >>>> * one runnable RT task. > >>>> */ > >>>> @@ -1063,6 +1095,8 @@ static inline void idle_balance(int cpu, struct rq *rq) > >>>> extern void sysrq_sched_debug_show(void); > >>>> extern void sched_init_granularity(void); > >>>> extern void update_max_interval(void); > >>>> + > >>>> +extern void init_sched_dl_class(void); > >>>> extern void init_sched_rt_class(void); > >>>> extern void init_sched_fair_class(void); > >>>> > >>> > >> > >> > > > >
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