| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Peter Zijlstra | 3818 | 37.30% | 64 | 27.95% |
| Steven Rostedt | 1572 | 15.36% | 21 | 9.17% |
| Gregory Haskins | 1424 | 13.91% | 26 | 11.35% |
| Nico Pitre | 1213 | 11.85% | 2 | 0.87% |
| Kirill V Tkhai | 523 | 5.11% | 16 | 6.99% |
| Ingo Molnar | 504 | 4.92% | 13 | 5.68% |
| Dmitry Adamushko | 136 | 1.33% | 5 | 2.18% |
| Rusty Russell | 119 | 1.16% | 7 | 3.06% |
| Yong Zhang | 86 | 0.84% | 2 | 0.87% |
| Frédéric Weisbecker | 82 | 0.80% | 3 | 1.31% |
| Vincent Guittot | 70 | 0.68% | 2 | 0.87% |
| Thomas Gleixner | 55 | 0.54% | 5 | 2.18% |
| Cheng Xu | 53 | 0.52% | 1 | 0.44% |
| Juri Lelli | 53 | 0.52% | 3 | 1.31% |
| Peter Williams | 40 | 0.39% | 3 | 1.31% |
| Tim Chen | 38 | 0.37% | 1 | 0.44% |
| Mike Galbraith | 37 | 0.36% | 3 | 1.31% |
| Dave Kleikamp | 37 | 0.36% | 1 | 0.44% |
| Balbir Singh | 34 | 0.33% | 1 | 0.44% |
| Srivatsa Vaddagiri | 33 | 0.32% | 2 | 0.87% |
| Liu hailong | 22 | 0.21% | 1 | 0.44% |
| Dhaval Giani | 22 | 0.21% | 2 | 0.87% |
| Ying Xue | 20 | 0.20% | 1 | 0.44% |
| Colin Cross | 19 | 0.19% | 1 | 0.44% |
| Dario Faggioli | 19 | 0.19% | 1 | 0.44% |
| Hillf Danton | 17 | 0.17% | 2 | 0.87% |
| Xiaotian Feng | 16 | 0.16% | 1 | 0.44% |
| Wen Yang | 13 | 0.13% | 2 | 0.87% |
| John Blackwood | 13 | 0.13% | 1 | 0.44% |
| Wanpeng Li | 12 | 0.12% | 1 | 0.44% |
| Shile Zhang | 11 | 0.11% | 1 | 0.44% |
| Frank Mayhar | 10 | 0.10% | 1 | 0.44% |
| Jiri Slaby | 9 | 0.09% | 1 | 0.44% |
| Dimitri Sivanich | 8 | 0.08% | 1 | 0.44% |
| Paul E. McKenney | 8 | 0.08% | 1 | 0.44% |
| Clark Williams | 7 | 0.07% | 1 | 0.44% |
| Matt Fleming | 7 | 0.07% | 1 | 0.44% |
| Xunlei Pang | 6 | 0.06% | 1 | 0.44% |
| Li Zefan | 6 | 0.06% | 2 | 0.87% |
| Kees Cook | 6 | 0.06% | 1 | 0.44% |
| Davidlohr Bueso A | 6 | 0.06% | 2 | 0.87% |
| Yanmin Zhang | 6 | 0.06% | 1 | 0.44% |
| Peter Boonstoppel | 6 | 0.06% | 1 | 0.44% |
| Stanislaw Gruszka | 5 | 0.05% | 1 | 0.44% |
| Lucas De Marchi | 5 | 0.05% | 2 | 0.87% |
| Mike Travis | 5 | 0.05% | 1 | 0.44% |
| Giedrius Rekasius | 5 | 0.05% | 1 | 0.44% |
| Shawn Bohrer | 4 | 0.04% | 2 | 0.87% |
| Sebastian Andrzej Siewior | 3 | 0.03% | 1 | 0.44% |
| Christoph Lameter | 1 | 0.01% | 1 | 0.44% |
| Nathan Zimmer | 1 | 0.01% | 1 | 0.44% |
| Greg Kroah-Hartman | 1 | 0.01% | 1 | 0.44% |
| John Stultz | 1 | 0.01% | 1 | 0.44% |
| Li Bin | 1 | 0.01% | 1 | 0.44% |
| Richard Weinberger | 1 | 0.01% | 1 | 0.44% |
| Shan Hai | 1 | 0.01% | 1 | 0.44% |
| H Hartley Sweeten | 1 | 0.01% | 1 | 0.44% |
| Jason Low | 1 | 0.01% | 1 | 0.44% |
| Yinghai Lu | 1 | 0.01% | 1 | 0.44% |
| Song Muchun | 1 | 0.01% | 1 | 0.44% |
| Tejun Heo | 1 | 0.01% | 1 | 0.44% |
| Total | 10235 | 229 |
// SPDX-License-Identifier: GPL-2.0 /* * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR * policies) */ #include "sched.h" #include "pelt.h" int sched_rr_timeslice = RR_TIMESLICE; int sysctl_sched_rr_timeslice = (MSEC_PER_SEC / HZ) * RR_TIMESLICE; 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); int idle = 0; int overrun; raw_spin_lock(&rt_b->rt_runtime_lock); for (;;) { overrun = hrtimer_forward_now(timer, rt_b->rt_period); if (!overrun) break; raw_spin_unlock(&rt_b->rt_runtime_lock); idle = do_sched_rt_period_timer(rt_b, overrun); raw_spin_lock(&rt_b->rt_runtime_lock); } if (idle) rt_b->rt_period_active = 0; raw_spin_unlock(&rt_b->rt_runtime_lock); 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; raw_spin_lock(&rt_b->rt_runtime_lock); if (!rt_b->rt_period_active) { rt_b->rt_period_active = 1; /* * SCHED_DEADLINE updates the bandwidth, as a run away * RT task with a DL task could hog a CPU. But DL does * not reset the period. If a deadline task was running * without an RT task running, it can cause RT tasks to * throttle when they start up. Kick the timer right away * to update the period. */ hrtimer_forward_now(&rt_b->rt_period_timer, ns_to_ktime(0)); hrtimer_start_expires(&rt_b->rt_period_timer, HRTIMER_MODE_ABS_PINNED); } raw_spin_unlock(&rt_b->rt_runtime_lock); } void init_rt_rq(struct rt_rq *rt_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 /* CONFIG_SMP */ /* We start is dequeued state, because no RT tasks are queued */ rt_rq->rt_queued = 0; rt_rq->rt_time = 0; rt_rq->rt_throttled = 0; rt_rq->rt_runtime = 0; raw_spin_lock_init(&rt_rq->rt_runtime_lock); } #ifdef CONFIG_RT_GROUP_SCHED static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b) { hrtimer_cancel(&rt_b->rt_period_timer); } #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; } static inline struct rq *rq_of_rt_se(struct sched_rt_entity *rt_se) { struct rt_rq *rt_rq = rt_se->rt_rq; return rt_rq->rq; } 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 = kcalloc(nr_cpu_ids, sizeof(rt_rq), GFP_KERNEL); if (!tg->rt_rq) goto err; tg->rt_se = kcalloc(nr_cpu_ids, sizeof(rt_se), 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); 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; } #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 rq *rq_of_rt_se(struct sched_rt_entity *rt_se) { struct task_struct *p = rt_task_of(rt_se); return task_rq(p); } static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se) { struct rq *rq = rq_of_rt_se(rt_se); return &rq->rt; } void free_rt_sched_group(struct task_group *tg) { } int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent) { return 1; } #endif /* CONFIG_RT_GROUP_SCHED */ #ifdef CONFIG_SMP static void pull_rt_task(struct rq *this_rq); static inline bool need_pull_rt_task(struct rq *rq, struct task_struct *prev) { /* Try to pull RT tasks here if we lower this rq's prio */ return rq->rt.highest_prio.curr > prev->prio; } 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. * * Matched by the barrier in pull_rt_task(). */ smp_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) { struct task_struct *p; if (!rt_entity_is_task(rt_se)) return; p = rt_task_of(rt_se); rt_rq = &rq_of_rt_rq(rt_rq)->rt; rt_rq->rt_nr_total++; if (p->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) { struct task_struct *p; if (!rt_entity_is_task(rt_se)) return; p = rt_task_of(rt_se); rt_rq = &rq_of_rt_rq(rt_rq)->rt; rt_rq->rt_nr_total--; if (p->nr_cpus_allowed > 1) rt_rq->rt_nr_migratory--; update_rt_migration(rt_rq); } static inline int has_pushable_tasks(struct rq *rq) { return !plist_head_empty(&rq->rt.pushable_tasks); } static DEFINE_PER_CPU(struct callback_head, rt_push_head); static DEFINE_PER_CPU(struct callback_head, rt_pull_head); static void push_rt_tasks(struct rq *); static void pull_rt_task(struct rq *); static inline void rt_queue_push_tasks(struct rq *rq) { if (!has_pushable_tasks(rq)) return; queue_balance_callback(rq, &per_cpu(rt_push_head, rq->cpu), push_rt_tasks); } static inline void rt_queue_pull_task(struct rq *rq) { queue_balance_callback(rq, &per_cpu(rt_pull_head, rq->cpu), pull_rt_task); } 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); /* Update the highest prio pushable task */ if (p->prio < rq->rt.highest_prio.next) rq->rt.highest_prio.next = p->prio; } static void dequeue_pushable_task(struct rq *rq, struct task_struct *p) { plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks); /* 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; } #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) { } static inline bool need_pull_rt_task(struct rq *rq, struct task_struct *prev) { return false; } static inline void pull_rt_task(struct rq *this_rq) { } static inline void rt_queue_push_tasks(struct rq *rq) { } #endif /* CONFIG_SMP */ static void enqueue_top_rt_rq(struct rt_rq *rt_rq); static void dequeue_top_rt_rq(struct rt_rq *rt_rq); static inline int on_rt_rq(struct sched_rt_entity *rt_se) { return rt_se->on_rq; } #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; 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)]);) #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, unsigned int flags); static void dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags); static void sched_rt_rq_enqueue(struct rt_rq *rt_rq) { struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr; struct rq *rq = rq_of_rt_rq(rt_rq); struct sched_rt_entity *rt_se; int cpu = cpu_of(rq); rt_se = rt_rq->tg->rt_se[cpu]; if (rt_rq->rt_nr_running) { if (!rt_se) enqueue_top_rt_rq(rt_rq); else if (!on_rt_rq(rt_se)) enqueue_rt_entity(rt_se, 0); if (rt_rq->highest_prio.curr < curr->prio) resched_curr(rq); } } 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) { dequeue_top_rt_rq(rt_rq); /* Kick cpufreq (see the comment in kernel/sched/sched.h). */ cpufreq_update_util(rq_of_rt_rq(rt_rq), 0); } else if (on_rt_rq(rt_se)) dequeue_rt_entity(rt_se, 0); } 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 this_rq()->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) #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) { struct rq *rq = rq_of_rt_rq(rt_rq); if (!rt_rq->rt_nr_running) return; enqueue_top_rt_rq(rt_rq); resched_curr(rq); } static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq) { dequeue_top_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 */ bool sched_rt_bandwidth_account(struct rt_rq *rt_rq) { struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); return (hrtimer_active(&rt_b->rt_period_timer) || rt_rq->rt_time < rt_b->rt_runtime); } #ifdef CONFIG_SMP /* * We ran out of runtime, see if we can borrow some from our neighbours. */ static void do_balance_runtime(struct rt_rq *rt_rq) { struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); struct root_domain *rd = rq_of_rt_rq(rt_rq)->rd; int i, weight; 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; 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); } /* * 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; rt_rq->rt_throttled = 0; raw_spin_unlock(&rt_rq->rt_runtime_lock); raw_spin_unlock(&rt_b->rt_runtime_lock); /* Make rt_rq available for pick_next_task() */ sched_rt_rq_enqueue(rt_rq); } } 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 balance_runtime(struct rt_rq *rt_rq) { if (!sched_feat(RT_RUNTIME_SHARE)) return; if (rt_rq->rt_time > rt_rq->rt_runtime) { raw_spin_unlock(&rt_rq->rt_runtime_lock); do_balance_runtime(rt_rq); raw_spin_lock(&rt_rq->rt_runtime_lock); } } #else /* !CONFIG_SMP */ static inline void balance_runtime(struct rt_rq *rt_rq) {} #endif /* CONFIG_SMP */ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun) { int i, idle = 1, throttled = 0; const struct cpumask *span; span = sched_rt_period_mask(); #ifdef CONFIG_RT_GROUP_SCHED /* * FIXME: isolated CPUs should really leave the root task group, * whether they are isolcpus or were isolated via cpusets, lest * the timer run on a CPU which does not service all runqueues, * potentially leaving other CPUs indefinitely throttled. If * isolation is really required, the user will turn the throttle * off to kill the perturbations it causes anyway. Meanwhile, * this maintains functionality for boot and/or troubleshooting. */ if (rt_b == &root_task_group.rt_bandwidth) span = cpu_online_mask; #endif 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); int skip; /* * When span == cpu_online_mask, taking each rq->lock * can be time-consuming. Try to avoid it when possible. */ raw_spin_lock(&rt_rq->rt_runtime_lock); if (!sched_feat(RT_RUNTIME_SHARE) && rt_rq->rt_runtime != RUNTIME_INF) rt_rq->rt_runtime = rt_b->rt_runtime; skip = !rt_rq->rt_time && !rt_rq->rt_nr_running; raw_spin_unlock(&rt_rq->rt_runtime_lock); if (skip) continue; raw_spin_lock(&rq->lock); update_rq_clock(rq); 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; /* * When we're idle and a woken (rt) task is * throttled check_preempt_curr() will set * skip_update and the time between the wakeup * and this unthrottle will get accounted as * 'runtime'. */ if (rt_rq->rt_nr_running && rq->curr == rq->idle) rq_clock_cancel_skipupdate(rq); } 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 (rt_rq->rt_throttled) throttled = 1; if (enqueue) sched_rt_rq_enqueue(rt_rq); raw_spin_unlock(&rq->lock); } if (!throttled && (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)) return 1; 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 (runtime >= 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) { struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); /* * Don't actually throttle groups that have no runtime assigned * but accrue some time due to boosting. */ if (likely(rt_b->rt_runtime)) { rt_rq->rt_throttled = 1; printk_deferred_once("sched: RT throttling activated\n"); } else { /* * In case we did anyway, make it go away, * replenishment is a joke, since it will replenish us * with exactly 0 ns. */ rt_rq->rt_time = 0; } 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; u64 delta_exec; u64 now; if (curr->sched_class != &rt_sched_class) return; now = rq_clock_task(rq); delta_exec = now - curr->se.exec_start; if (unlikely((s64)delta_exec <= 0)) return; 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 = now; cgroup_account_cputime(curr, delta_exec); if (!rt_bandwidth_enabled()) return; for_each_sched_rt_entity(rt_se) { struct rt_rq *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_curr(rq); raw_spin_unlock(&rt_rq->rt_runtime_lock); } } } static void dequeue_top_rt_rq(struct rt_rq *rt_rq) { struct rq *rq = rq_of_rt_rq(rt_rq); BUG_ON(&rq->rt != rt_rq); if (!rt_rq->rt_queued) return; BUG_ON(!rq->nr_running); sub_nr_running(rq, rt_rq->rt_nr_running); rt_rq->rt_queued = 0; } static void enqueue_top_rt_rq(struct rt_rq *rt_rq) { struct rq *rq = rq_of_rt_rq(rt_rq); BUG_ON(&rq->rt != rt_rq); if (rt_rq->rt_queued) return; if (rt_rq_throttled(rt_rq)) return; if (rt_rq->rt_nr_running) { add_nr_running(rq, rt_rq->rt_nr_running); rt_rq->rt_queued = 1; } /* Kick cpufreq (see the comment in kernel/sched/sched.h). */ cpufreq_update_util(rq, 0); } #if defined CONFIG_SMP 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); #ifdef CONFIG_RT_GROUP_SCHED /* * Change rq's cpupri only if rt_rq is the top queue. */ if (&rq->rt != rt_rq) return; #endif if (rq->online && prio < prev_prio) cpupri_set(&rq->rd->cpupri, rq->cpu, prio); } 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); #ifdef CONFIG_RT_GROUP_SCHED /* * Change rq's cpupri only if rt_rq is the top queue. */ if (&rq->rt != rt_rq) return; #endif 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 unsigned int rt_se_nr_running(struct sched_rt_entity *rt_se) { struct rt_rq *group_rq = group_rt_rq(rt_se); if (group_rq) return group_rq->rt_nr_running; else return 1; } static inline unsigned int rt_se_rr_nr_running(struct sched_rt_entity *rt_se) { struct rt_rq *group_rq = group_rt_rq(rt_se); struct task_struct *tsk; if (group_rq) return group_rq->rr_nr_running; tsk = rt_task_of(rt_se); return (tsk->policy == SCHED_RR) ? 1 : 0; } 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 += rt_se_nr_running(rt_se); rt_rq->rr_nr_running += rt_se_rr_nr_running(rt_se); 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 -= rt_se_nr_running(rt_se); rt_rq->rr_nr_running -= rt_se_rr_nr_running(rt_se); dec_rt_prio(rt_rq, rt_se_prio(rt_se)); dec_rt_migration(rt_se, rt_rq); dec_rt_group(rt_se, rt_rq); } /* * Change rt_se->run_list location unless SAVE && !MOVE * * assumes ENQUEUE/DEQUEUE flags match */ static inline bool move_entity(unsigned int flags) { if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) == DEQUEUE_SAVE) return false; return true; } static void __delist_rt_entity(struct sched_rt_entity *rt_se, struct rt_prio_array *array) { 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); rt_se->on_list = 0; } static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags) { 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)) { if (rt_se->on_list) __delist_rt_entity(rt_se, array); return; } if (move_entity(flags)) { WARN_ON_ONCE(rt_se->on_list); if (flags & ENQUEUE_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); rt_se->on_list = 1; } rt_se->on_rq = 1; inc_rt_tasks(rt_se, rt_rq); } static void __dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags) { struct rt_rq *rt_rq = rt_rq_of_se(rt_se); struct rt_prio_array *array = &rt_rq->active; if (move_entity(flags)) { WARN_ON_ONCE(!rt_se->on_list); __delist_rt_entity(rt_se, array); } rt_se->on_rq = 0; dec_rt_tasks(rt_se, rt_rq); } /* * Because the prio of an upper entry depends on the lower * entries, we must remove entries top - down. */ static void dequeue_rt_stack(struct sched_rt_entity *rt_se, unsigned int flags) { struct sched_rt_entity *back = NULL; for_each_sched_rt_entity(rt_se) { rt_se->back = back; back = rt_se; } dequeue_top_rt_rq(rt_rq_of_se(back)); for (rt_se = back; rt_se; rt_se = rt_se->back) { if (on_rt_rq(rt_se)) __dequeue_rt_entity(rt_se, flags); } } static void enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags) { struct rq *rq = rq_of_rt_se(rt_se); dequeue_rt_stack(rt_se, flags); for_each_sched_rt_entity(rt_se) __enqueue_rt_entity(rt_se, flags); enqueue_top_rt_rq(&rq->rt); } static void dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags) { struct rq *rq = rq_of_rt_se(rt_se); dequeue_rt_stack(rt_se, flags); 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, flags); } enqueue_top_rt_rq(&rq->rt); } /* * 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); if (!task_current(rq, p) && p->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, flags); dequeue_pushable_task(rq, p); } /* * Put task to the head or 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 cpu, int sd_flag, int flags) { struct task_struct *curr; struct rq *rq; /* For anything but wake ups, just return the task_cpu */ if (sd_flag != SD_BALANCE_WAKE && sd_flag != SD_BALANCE_FORK) goto out; rq = cpu_rq(cpu); rcu_read_lock(); curr = READ_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->nr_cpus_allowed < 2 || curr->prio <= p->prio)) { int target = find_lowest_rq(p); /* * Don't bother moving it if the destination CPU is * not running a lower priority task. */ if (target != -1 && p->prio < cpu_rq(target)->rt.highest_prio.curr) cpu = target; } rcu_read_unlock(); out: return cpu; } static void check_preempt_equal_prio(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 || !cpupri_find(&rq->rd->cpupri, rq->curr, NULL)) 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 && cpupri_find(&rq->rd->cpupri, p, NULL)) return; /* * There appear to be other CPUs that can accept * the current task but none can run 'p', so lets reschedule * to try and push the current task away: */ requeue_task_rt(rq, p, 1); resched_curr(rq); } #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_curr(rq); 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 = &rq->rt; 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(rq); return p; } static struct task_struct * pick_next_task_rt(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) { struct task_struct *p; struct rt_rq *rt_rq = &rq->rt; if (need_pull_rt_task(rq, prev)) { /* * This is OK, because current is on_cpu, which avoids it being * picked for load-balance and preemption/IRQs are still * disabled avoiding further scheduler activity on it and we're * being very careful to re-start the picking loop. */ rq_unpin_lock(rq, rf); pull_rt_task(rq); rq_repin_lock(rq, rf); /* * pull_rt_task() can drop (and re-acquire) rq->lock; this * means a dl or stop task can slip in, in which case we need * to re-start task selection. */ if (unlikely((rq->stop && task_on_rq_queued(rq->stop)) || rq->dl.dl_nr_running)) return RETRY_TASK; } /* * We may dequeue prev's rt_rq in put_prev_task(). * So, we update time before rt_queued check. */ if (prev->sched_class == &rt_sched_class) update_curr_rt(rq); if (!rt_rq->rt_queued) return NULL; put_prev_task(rq, prev); p = _pick_next_task_rt(rq); /* The running task is never eligible for pushing */ dequeue_pushable_task(rq, p); rt_queue_push_tasks(rq); /* * If prev task was rt, put_prev_task() has already updated the * utilization. We only care of the case where we start to schedule a * rt task */ if (rq->curr->sched_class != &rt_sched_class) update_rt_rq_load_avg(rq_clock_task(rq), rq, 0); return p; } static void put_prev_task_rt(struct rq *rq, struct task_struct *p) { update_curr_rt(rq); update_rt_rq_load_avg(rq_clock_task(rq), rq, 1); /* * The previous task needs to be made eligible for pushing * if it is still active */ if (on_rt_rq(&p->rt) && p->nr_cpus_allowed > 1) enqueue_pushable_task(rq, p); } #ifdef CONFIG_SMP /* Only try algorithms three times */ #define RT_MAX_TRIES 3 static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu) { if (!task_running(rq, p) && cpumask_test_cpu(cpu, &p->cpus_allowed)) return 1; return 0; } /* * Return the highest pushable rq's task, which is suitable to be executed * on the CPU, NULL otherwise */ static struct task_struct *pick_highest_pushable_task(struct rq *rq, int cpu) { struct plist_head *head = &rq->rt.pushable_tasks; struct task_struct *p; if (!has_pushable_tasks(rq)) return NULL; plist_for_each_entry(p, head, pushable_tasks) { if (pick_rt_task(rq, p, cpu)) return p; } return NULL; } 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 = this_cpu_cpumask_var_ptr(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->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 (lowest_rq->rt.highest_prio.curr <= task->prio) { /* * Target rq has tasks of equal or higher priority, * retrying does not release any lock and is unlikely * to yield a different result. */ lowest_rq = NULL; break; } /* 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) || !rt_task(task) || !task_on_rq_queued(task))) { double_unlock_balance(rq, lowest_rq); 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->nr_cpus_allowed <= 1); BUG_ON(!task_on_rq_queued(p)); 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; int ret = 0; 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_curr(rq); 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 == next_task) { /* * 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. */ 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); ret = 1; resched_curr(lowest_rq); double_unlock_balance(rq, lowest_rq); out: put_task_struct(next_task); return ret; } static void push_rt_tasks(struct rq *rq) { /* push_rt_task will return true if it moved an RT */ while (push_rt_task(rq)) ; } #ifdef HAVE_RT_PUSH_IPI /* * When a high priority task schedules out from a CPU and a lower priority * task is scheduled in, a check is made to see if there's any RT tasks * on other CPUs that are waiting to run because a higher priority RT task * is currently running on its CPU. In this case, the CPU with multiple RT * tasks queued on it (overloaded) needs to be notified that a CPU has opened * up that may be able to run one of its non-running queued RT tasks. * * All CPUs with overloaded RT tasks need to be notified as there is currently * no way to know which of these CPUs have the highest priority task waiting * to run. Instead of trying to take a spinlock on each of these CPUs, * which has shown to cause large latency when done on machines with many * CPUs, sending an IPI to the CPUs to have them push off the overloaded * RT tasks waiting to run. * * Just sending an IPI to each of the CPUs is also an issue, as on large * count CPU machines, this can cause an IPI storm on a CPU, especially * if its the only CPU with multiple RT tasks queued, and a large number * of CPUs scheduling a lower priority task at the same time. * * Each root domain has its own irq work function that can iterate over * all CPUs with RT overloaded tasks. Since all CPUs with overloaded RT * tassk must be checked if there's one or many CPUs that are lowering * their priority, there's a single irq work iterator that will try to * push off RT tasks that are waiting to run. * * When a CPU schedules a lower priority task, it will kick off the * irq work iterator that will jump to each CPU with overloaded RT tasks. * As it only takes the first CPU that schedules a lower priority task * to start the process, the rto_start variable is incremented and if * the atomic result is one, then that CPU will try to take the rto_lock. * This prevents high contention on the lock as the process handles all * CPUs scheduling lower priority tasks. * * All CPUs that are scheduling a lower priority task will increment the * rt_loop_next variable. This will make sure that the irq work iterator * checks all RT overloaded CPUs whenever a CPU schedules a new lower * priority task, even if the iterator is in the middle of a scan. Incrementing * the rt_loop_next will cause the iterator to perform another scan. * */ static int rto_next_cpu(struct root_domain *rd) { int next; int cpu; /* * When starting the IPI RT pushing, the rto_cpu is set to -1, * rt_next_cpu() will simply return the first CPU found in * the rto_mask. * * If rto_next_cpu() is called with rto_cpu is a valid CPU, it * will return the next CPU found in the rto_mask. * * If there are no more CPUs left in the rto_mask, then a check is made * against rto_loop and rto_loop_next. rto_loop is only updated with * the rto_lock held, but any CPU may increment the rto_loop_next * without any locking. */ for (;;) { /* When rto_cpu is -1 this acts like cpumask_first() */ cpu = cpumask_next(rd->rto_cpu, rd->rto_mask); rd->rto_cpu = cpu; if (cpu < nr_cpu_ids) return cpu; rd->rto_cpu = -1; /* * ACQUIRE ensures we see the @rto_mask changes * made prior to the @next value observed. * * Matches WMB in rt_set_overload(). */ next = atomic_read_acquire(&rd->rto_loop_next); if (rd->rto_loop == next) break; rd->rto_loop = next; } return -1; } static inline bool rto_start_trylock(atomic_t *v) { return !atomic_cmpxchg_acquire(v, 0, 1); } static inline void rto_start_unlock(atomic_t *v) { atomic_set_release(v, 0); } static void tell_cpu_to_push(struct rq *rq) { int cpu = -1; /* Keep the loop going if the IPI is currently active */ atomic_inc(&rq->rd->rto_loop_next); /* Only one CPU can initiate a loop at a time */ if (!rto_start_trylock(&rq->rd->rto_loop_start)) return; raw_spin_lock(&rq->rd->rto_lock); /* * The rto_cpu is updated under the lock, if it has a valid CPU * then the IPI is still running and will continue due to the * update to loop_next, and nothing needs to be done here. * Otherwise it is finishing up and an ipi needs to be sent. */ if (rq->rd->rto_cpu < 0) cpu = rto_next_cpu(rq->rd); raw_spin_unlock(&rq->rd->rto_lock); rto_start_unlock(&rq->rd->rto_loop_start); if (cpu >= 0) { /* Make sure the rd does not get freed while pushing */ sched_get_rd(rq->rd); irq_work_queue_on(&rq->rd->rto_push_work, cpu); } } /* Called from hardirq context */ void rto_push_irq_work_func(struct irq_work *work) { struct root_domain *rd = container_of(work, struct root_domain, rto_push_work); struct rq *rq; int cpu; rq = this_rq(); /* * We do not need to grab the lock to check for has_pushable_tasks. * When it gets updated, a check is made if a push is possible. */ if (has_pushable_tasks(rq)) { raw_spin_lock(&rq->lock); push_rt_tasks(rq); raw_spin_unlock(&rq->lock); } raw_spin_lock(&rd->rto_lock); /* Pass the IPI to the next rt overloaded queue */ cpu = rto_next_cpu(rd); raw_spin_unlock(&rd->rto_lock); if (cpu < 0) { sched_put_rd(rd); return; } /* Try the next RT overloaded CPU */ irq_work_queue_on(&rd->rto_push_work, cpu); } #endif /* HAVE_RT_PUSH_IPI */ static void pull_rt_task(struct rq *this_rq) { int this_cpu = this_rq->cpu, cpu; bool resched = false; struct task_struct *p; struct rq *src_rq; int rt_overload_count = rt_overloaded(this_rq); if (likely(!rt_overload_count)) return; /* * Match the barrier from rt_set_overloaded; this guarantees that if we * see overloaded we must also see the rto_mask bit. */ smp_rmb(); /* If we are the only overloaded CPU do nothing */ if (rt_overload_count == 1 && cpumask_test_cpu(this_rq->cpu, this_rq->rd->rto_mask)) return; #ifdef HAVE_RT_PUSH_IPI if (sched_feat(RT_PUSH_IPI)) { tell_cpu_to_push(this_rq); return; } #endif 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); /* * We can pull only a task, which is pushable * on its rq, and no others. */ p = pick_highest_pushable_task(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(!task_on_rq_queued(p)); /* * 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; resched = true; 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); } if (resched) resched_curr(this_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) && p->nr_cpus_allowed > 1 && (dl_task(rq->curr) || rt_task(rq->curr)) && (rq->curr->nr_cpus_allowed < 2 || rq->curr->prio <= p->prio)) push_rt_tasks(rq); } /* 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 (!task_on_rq_queued(p) || rq->rt.rt_nr_running) return; rt_queue_pull_task(rq); } void __init 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) { /* * 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 (task_on_rq_queued(p) && rq->curr != p) { #ifdef CONFIG_SMP if (p->nr_cpus_allowed > 1 && rq->rt.overloaded) rt_queue_push_tasks(rq); #endif /* CONFIG_SMP */ if (p->prio < rq->curr->prio && cpu_online(cpu_of(rq))) resched_curr(rq); } } /* * 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 (!task_on_rq_queued(p)) 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) rt_queue_pull_task(rq); /* * If there's a higher priority task waiting to run * then reschedule. */ if (p->prio > rq->rt.highest_prio.curr) resched_curr(rq); #else /* For UP simply resched on drop of prio */ if (oldprio < p->prio) resched_curr(rq); #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_curr(rq); } } #ifdef CONFIG_POSIX_TIMERS 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; if (p->rt.watchdog_stamp != jiffies) { p->rt.timeout++; p->rt.watchdog_stamp = jiffies; } 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; } } #else static inline void watchdog(struct rq *rq, struct task_struct *p) { } #endif /* * scheduler tick hitting a task of our scheduling class. * * NOTE: This function can be called remotely by the tick offload that * goes along full dynticks. Therefore no local assumption can be made * and everything must be accessed through the @rq and @curr passed in * parameters. */ static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued) { struct sched_rt_entity *rt_se = &p->rt; update_curr_rt(rq); update_rt_rq_load_avg(rq_clock_task(rq), rq, 1); 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 = sched_rr_timeslice; /* * Requeue to the end of queue if we (and all of our ancestors) are not * the only element on the queue */ for_each_sched_rt_entity(rt_se) { if (rt_se->run_list.prev != rt_se->run_list.next) { requeue_task_rt(rq, p, 0); resched_curr(rq); return; } } } static void set_curr_task_rt(struct rq *rq) { struct task_struct *p = rq->curr; p->se.exec_start = rq_clock_task(rq); /* 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 sched_rr_timeslice; else return 0; } 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_common, .rq_online = rq_online_rt, .rq_offline = rq_offline_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, .update_curr = update_curr_rt, }; #ifdef CONFIG_RT_GROUP_SCHED /* * Ensure that the real time constraints are schedulable. */ static DEFINE_MUTEX(rt_constraints_mutex); /* Must be called with tasklist_lock held */ static inline int tg_has_rt_tasks(struct task_group *tg) { struct task_struct *g, *p; /* * Autogroups do not have RT tasks; see autogroup_create(). */ if (task_group_is_autogroup(tg)) return 0; for_each_process_thread(g, p) { if (rt_task(p) && task_group(p) == tg) return 1; } return 0; } struct rt_schedulable_data { struct task_group *tg; u64 rt_period; u64 rt_runtime; }; static int tg_rt_schedulable(struct task_group *tg, void *data) { struct rt_schedulable_data *d = data; struct task_group *child; unsigned long total, sum = 0; u64 period, runtime; period = ktime_to_ns(tg->rt_bandwidth.rt_period); runtime = tg->rt_bandwidth.rt_runtime; if (tg == d->tg) { period = d->rt_period; runtime = d->rt_runtime; } /* * Cannot have more runtime than the period. */ if (runtime > period && runtime != RUNTIME_INF) return -EINVAL; /* * Ensure we don't starve existing RT tasks. */ if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) return -EBUSY; total = to_ratio(period, runtime); /* * Nobody can have more than the global setting allows. */ if (total > to_ratio(global_rt_period(), global_rt_runtime())) return -EINVAL; /* * The sum of our children's runtime should not exceed our own. */ list_for_each_entry_rcu(child, &tg->children, siblings) { period = ktime_to_ns(child->rt_bandwidth.rt_period); runtime = child->rt_bandwidth.rt_runtime; if (child == d->tg) { period = d->rt_period; runtime = d->rt_runtime; } sum += to_ratio(period, runtime); } if (sum > total) return -EINVAL; return 0; } static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) { int ret; struct rt_schedulable_data data = { .tg = tg, .rt_period = period, .rt_runtime = runtime, }; rcu_read_lock(); ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); rcu_read_unlock(); return ret; } static int tg_set_rt_bandwidth(struct task_group *tg, u64 rt_period, u64 rt_runtime) { int i, err = 0; /* * Disallowing the root group RT runtime is BAD, it would disallow the * kernel creating (and or operating) RT threads. */ if (tg == &root_task_group && rt_runtime == 0) return -EINVAL; /* No period doesn't make any sense. */ if (rt_period == 0) return -EINVAL; mutex_lock(&rt_constraints_mutex); read_lock(&tasklist_lock); err = __rt_schedulable(tg, rt_period, rt_runtime); if (err) goto unlock; raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); tg->rt_bandwidth.rt_runtime = rt_runtime; for_each_possible_cpu(i) { struct rt_rq *rt_rq = tg->rt_rq[i]; raw_spin_lock(&rt_rq->rt_runtime_lock); rt_rq->rt_runtime = rt_runtime; raw_spin_unlock(&rt_rq->rt_runtime_lock); } raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); unlock: read_unlock(&tasklist_lock); mutex_unlock(&rt_constraints_mutex); return err; } int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) { u64 rt_runtime, rt_period; rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; if (rt_runtime_us < 0) rt_runtime = RUNTIME_INF; return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); } long sched_group_rt_runtime(struct task_group *tg) { u64 rt_runtime_us; if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) return -1; rt_runtime_us = tg->rt_bandwidth.rt_runtime; do_div(rt_runtime_us, NSEC_PER_USEC); return rt_runtime_us; } int sched_group_set_rt_period(struct task_group *tg, u64 rt_period_us) { u64 rt_runtime, rt_period; rt_period = rt_period_us * NSEC_PER_USEC; rt_runtime = tg->rt_bandwidth.rt_runtime; return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); } long sched_group_rt_period(struct task_group *tg) { u64 rt_period_us; rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); do_div(rt_period_us, NSEC_PER_USEC); return rt_period_us; } static int sched_rt_global_constraints(void) { int ret = 0; mutex_lock(&rt_constraints_mutex); read_lock(&tasklist_lock); ret = __rt_schedulable(NULL, 0, 0); read_unlock(&tasklist_lock); mutex_unlock(&rt_constraints_mutex); return ret; } int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) { /* Don't accept realtime tasks when there is no way for them to run */ if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) return 0; return 1; } #else /* !CONFIG_RT_GROUP_SCHED */ static int sched_rt_global_constraints(void) { unsigned long flags; int i; raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); for_each_possible_cpu(i) { struct rt_rq *rt_rq = &cpu_rq(i)->rt; raw_spin_lock(&rt_rq->rt_runtime_lock); rt_rq->rt_runtime = global_rt_runtime(); raw_spin_unlock(&rt_rq->rt_runtime_lock); } raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); return 0; } #endif /* CONFIG_RT_GROUP_SCHED */ static int sched_rt_global_validate(void) { if (sysctl_sched_rt_period <= 0) return -EINVAL; if ((sysctl_sched_rt_runtime != RUNTIME_INF) && (sysctl_sched_rt_runtime > sysctl_sched_rt_period)) return -EINVAL; return 0; } static void sched_rt_do_global(void) { def_rt_bandwidth.rt_runtime = global_rt_runtime(); def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period()); } int sched_rt_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { int old_period, old_runtime; static DEFINE_MUTEX(mutex); int ret; mutex_lock(&mutex); old_period = sysctl_sched_rt_period; old_runtime = sysctl_sched_rt_runtime; ret = proc_dointvec(table, write, buffer, lenp, ppos); if (!ret && write) { ret = sched_rt_global_validate(); if (ret) goto undo; ret = sched_dl_global_validate(); if (ret) goto undo; ret = sched_rt_global_constraints(); if (ret) goto undo; sched_rt_do_global(); sched_dl_do_global(); } if (0) { undo: sysctl_sched_rt_period = old_period; sysctl_sched_rt_runtime = old_runtime; } mutex_unlock(&mutex); return ret; } int sched_rr_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { int ret; static DEFINE_MUTEX(mutex); mutex_lock(&mutex); ret = proc_dointvec(table, write, buffer, lenp, ppos); /* * Make sure that internally we keep jiffies. * Also, writing zero resets the timeslice to default: */ if (!ret && write) { sched_rr_timeslice = sysctl_sched_rr_timeslice <= 0 ? RR_TIMESLICE : msecs_to_jiffies(sysctl_sched_rr_timeslice); } mutex_unlock(&mutex); return ret; } #ifdef CONFIG_SCHED_DEBUG 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 */
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