diff options
Diffstat (limited to 'kernel/sched.c')
-rw-r--r-- | kernel/sched.c | 707 |
1 files changed, 553 insertions, 154 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index d258b2d9a66d..0e9344a71be3 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -196,10 +196,28 @@ static inline int rt_bandwidth_enabled(void) return sysctl_sched_rt_runtime >= 0; } -static void start_rt_bandwidth(struct rt_bandwidth *rt_b) +static void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period) { - ktime_t now; + unsigned long delta; + ktime_t soft, hard, now; + + for (;;) { + if (hrtimer_active(period_timer)) + break; + + now = hrtimer_cb_get_time(period_timer); + hrtimer_forward(period_timer, now, period); + soft = hrtimer_get_softexpires(period_timer); + hard = hrtimer_get_expires(period_timer); + delta = ktime_to_ns(ktime_sub(hard, soft)); + __hrtimer_start_range_ns(period_timer, soft, delta, + HRTIMER_MODE_ABS_PINNED, 0); + } +} + +static void start_rt_bandwidth(struct rt_bandwidth *rt_b) +{ if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF) return; @@ -207,22 +225,7 @@ static void start_rt_bandwidth(struct rt_bandwidth *rt_b) return; raw_spin_lock(&rt_b->rt_runtime_lock); - for (;;) { - unsigned long delta; - ktime_t soft, hard; - - if (hrtimer_active(&rt_b->rt_period_timer)) - break; - - now = hrtimer_cb_get_time(&rt_b->rt_period_timer); - hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period); - - soft = hrtimer_get_softexpires(&rt_b->rt_period_timer); - hard = hrtimer_get_expires(&rt_b->rt_period_timer); - delta = ktime_to_ns(ktime_sub(hard, soft)); - __hrtimer_start_range_ns(&rt_b->rt_period_timer, soft, delta, - HRTIMER_MODE_ABS_PINNED, 0); - } + start_bandwidth_timer(&rt_b->rt_period_timer, rt_b->rt_period); raw_spin_unlock(&rt_b->rt_runtime_lock); } @@ -247,6 +250,24 @@ struct cfs_rq; static LIST_HEAD(task_groups); +struct cfs_bandwidth { +#ifdef CONFIG_CFS_BANDWIDTH + raw_spinlock_t lock; + ktime_t period; + u64 quota, runtime; + s64 hierarchal_quota; + u64 runtime_expires; + + int idle, timer_active; + struct hrtimer period_timer, slack_timer; + struct list_head throttled_cfs_rq; + + /* statistics */ + int nr_periods, nr_throttled; + u64 throttled_time; +#endif +}; + /* task group related information */ struct task_group { struct cgroup_subsys_state css; @@ -278,6 +299,8 @@ struct task_group { #ifdef CONFIG_SCHED_AUTOGROUP struct autogroup *autogroup; #endif + + struct cfs_bandwidth cfs_bandwidth; }; /* task_group_lock serializes the addition/removal of task groups */ @@ -311,7 +334,7 @@ struct task_group root_task_group; /* CFS-related fields in a runqueue */ struct cfs_rq { struct load_weight load; - unsigned long nr_running; + unsigned long nr_running, h_nr_running; u64 exec_clock; u64 min_vruntime; @@ -377,9 +400,120 @@ struct cfs_rq { unsigned long load_contribution; #endif +#ifdef CONFIG_CFS_BANDWIDTH + int runtime_enabled; + u64 runtime_expires; + s64 runtime_remaining; + + u64 throttled_timestamp; + int throttled, throttle_count; + struct list_head throttled_list; +#endif #endif }; +#ifdef CONFIG_FAIR_GROUP_SCHED +#ifdef CONFIG_CFS_BANDWIDTH +static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg) +{ + return &tg->cfs_bandwidth; +} + +static inline u64 default_cfs_period(void); +static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun); +static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b); + +static enum hrtimer_restart sched_cfs_slack_timer(struct hrtimer *timer) +{ + struct cfs_bandwidth *cfs_b = + container_of(timer, struct cfs_bandwidth, slack_timer); + do_sched_cfs_slack_timer(cfs_b); + + return HRTIMER_NORESTART; +} + +static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer) +{ + struct cfs_bandwidth *cfs_b = + container_of(timer, struct cfs_bandwidth, period_timer); + ktime_t now; + int overrun; + int idle = 0; + + for (;;) { + now = hrtimer_cb_get_time(timer); + overrun = hrtimer_forward(timer, now, cfs_b->period); + + if (!overrun) + break; + + idle = do_sched_cfs_period_timer(cfs_b, overrun); + } + + return idle ? HRTIMER_NORESTART : HRTIMER_RESTART; +} + +static void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) +{ + raw_spin_lock_init(&cfs_b->lock); + cfs_b->runtime = 0; + cfs_b->quota = RUNTIME_INF; + cfs_b->period = ns_to_ktime(default_cfs_period()); + + INIT_LIST_HEAD(&cfs_b->throttled_cfs_rq); + hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + cfs_b->period_timer.function = sched_cfs_period_timer; + hrtimer_init(&cfs_b->slack_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + cfs_b->slack_timer.function = sched_cfs_slack_timer; +} + +static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) +{ + cfs_rq->runtime_enabled = 0; + INIT_LIST_HEAD(&cfs_rq->throttled_list); +} + +/* requires cfs_b->lock, may release to reprogram timer */ +static void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b) +{ + /* + * The timer may be active because we're trying to set a new bandwidth + * period or because we're racing with the tear-down path + * (timer_active==0 becomes visible before the hrtimer call-back + * terminates). In either case we ensure that it's re-programmed + */ + while (unlikely(hrtimer_active(&cfs_b->period_timer))) { + raw_spin_unlock(&cfs_b->lock); + /* ensure cfs_b->lock is available while we wait */ + hrtimer_cancel(&cfs_b->period_timer); + + raw_spin_lock(&cfs_b->lock); + /* if someone else restarted the timer then we're done */ + if (cfs_b->timer_active) + return; + } + + cfs_b->timer_active = 1; + start_bandwidth_timer(&cfs_b->period_timer, cfs_b->period); +} + +static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) +{ + hrtimer_cancel(&cfs_b->period_timer); + hrtimer_cancel(&cfs_b->slack_timer); +} +#else +static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) {} +static void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {} +static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {} + +static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg) +{ + return NULL; +} +#endif /* CONFIG_CFS_BANDWIDTH */ +#endif /* CONFIG_FAIR_GROUP_SCHED */ + /* Real-Time classes' related field in a runqueue: */ struct rt_rq { struct rt_prio_array active; @@ -510,7 +644,7 @@ struct rq { unsigned long cpu_power; - unsigned char idle_at_tick; + unsigned char idle_balance; /* For active balancing */ int post_schedule; int active_balance; @@ -520,8 +654,6 @@ struct rq { int cpu; int online; - unsigned long avg_load_per_task; - u64 rt_avg; u64 age_stamp; u64 idle_stamp; @@ -570,7 +702,7 @@ struct rq { #endif #ifdef CONFIG_SMP - struct task_struct *wake_list; + struct llist_head wake_list; #endif }; @@ -1272,6 +1404,18 @@ void wake_up_idle_cpu(int cpu) smp_send_reschedule(cpu); } +static inline bool got_nohz_idle_kick(void) +{ + return idle_cpu(smp_processor_id()) && this_rq()->nohz_balance_kick; +} + +#else /* CONFIG_NO_HZ */ + +static inline bool got_nohz_idle_kick(void) +{ + return false; +} + #endif /* CONFIG_NO_HZ */ static u64 sched_avg_period(void) @@ -1471,24 +1615,28 @@ static inline void dec_cpu_load(struct rq *rq, unsigned long load) update_load_sub(&rq->load, load); } -#if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED) +#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \ + (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH))) typedef int (*tg_visitor)(struct task_group *, void *); /* - * Iterate the full tree, calling @down when first entering a node and @up when - * leaving it for the final time. + * Iterate task_group tree rooted at *from, calling @down when first entering a + * node and @up when leaving it for the final time. + * + * Caller must hold rcu_lock or sufficient equivalent. */ -static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data) +static int walk_tg_tree_from(struct task_group *from, + tg_visitor down, tg_visitor up, void *data) { struct task_group *parent, *child; int ret; - rcu_read_lock(); - parent = &root_task_group; + parent = from; + down: ret = (*down)(parent, data); if (ret) - goto out_unlock; + goto out; list_for_each_entry_rcu(child, &parent->children, siblings) { parent = child; goto down; @@ -1497,19 +1645,29 @@ up: continue; } ret = (*up)(parent, data); - if (ret) - goto out_unlock; + if (ret || parent == from) + goto out; child = parent; parent = parent->parent; if (parent) goto up; -out_unlock: - rcu_read_unlock(); - +out: return ret; } +/* + * Iterate the full tree, calling @down when first entering a node and @up when + * leaving it for the final time. + * + * Caller must hold rcu_lock or sufficient equivalent. + */ + +static inline int walk_tg_tree(tg_visitor down, tg_visitor up, void *data) +{ + return walk_tg_tree_from(&root_task_group, down, up, data); +} + static int tg_nop(struct task_group *tg, void *data) { return 0; @@ -1569,11 +1727,9 @@ static unsigned long cpu_avg_load_per_task(int cpu) unsigned long nr_running = ACCESS_ONCE(rq->nr_running); if (nr_running) - rq->avg_load_per_task = rq->load.weight / nr_running; - else - rq->avg_load_per_task = 0; + return rq->load.weight / nr_running; - return rq->avg_load_per_task; + return 0; } #ifdef CONFIG_PREEMPT @@ -1739,7 +1895,7 @@ static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) #ifdef CONFIG_SMP /* * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be - * successfuly executed on another CPU. We must ensure that updates of + * successfully executed on another CPU. We must ensure that updates of * per-task data have been completed by this moment. */ smp_wmb(); @@ -1806,7 +1962,6 @@ static void activate_task(struct rq *rq, struct task_struct *p, int flags) rq->nr_uninterruptible--; enqueue_task(rq, p, flags); - inc_nr_running(rq); } /* @@ -1818,7 +1973,6 @@ static void deactivate_task(struct rq *rq, struct task_struct *p, int flags) rq->nr_uninterruptible++; dequeue_task(rq, p, flags); - dec_nr_running(rq); } #ifdef CONFIG_IRQ_TIME_ACCOUNTING @@ -2390,11 +2544,11 @@ static int select_fallback_rq(int cpu, struct task_struct *p) /* Look for allowed, online CPU in same node. */ for_each_cpu_and(dest_cpu, nodemask, cpu_active_mask) - if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed)) + if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) return dest_cpu; /* Any allowed, online CPU? */ - dest_cpu = cpumask_any_and(&p->cpus_allowed, cpu_active_mask); + dest_cpu = cpumask_any_and(tsk_cpus_allowed(p), cpu_active_mask); if (dest_cpu < nr_cpu_ids) return dest_cpu; @@ -2431,7 +2585,7 @@ int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags) * [ this allows ->select_task() to simply return task_cpu(p) and * not worry about this generic constraint ] */ - if (unlikely(!cpumask_test_cpu(cpu, &p->cpus_allowed) || + if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) || !cpu_online(cpu))) cpu = select_fallback_rq(task_cpu(p), p); @@ -2556,42 +2710,26 @@ static int ttwu_remote(struct task_struct *p, int wake_flags) } #ifdef CONFIG_SMP -static void sched_ttwu_do_pending(struct task_struct *list) +static void sched_ttwu_pending(void) { struct rq *rq = this_rq(); + struct llist_node *llist = llist_del_all(&rq->wake_list); + struct task_struct *p; raw_spin_lock(&rq->lock); - while (list) { - struct task_struct *p = list; - list = list->wake_entry; + while (llist) { + p = llist_entry(llist, struct task_struct, wake_entry); + llist = llist_next(llist); ttwu_do_activate(rq, p, 0); } raw_spin_unlock(&rq->lock); } -#ifdef CONFIG_HOTPLUG_CPU - -static void sched_ttwu_pending(void) -{ - struct rq *rq = this_rq(); - struct task_struct *list = xchg(&rq->wake_list, NULL); - - if (!list) - return; - - sched_ttwu_do_pending(list); -} - -#endif /* CONFIG_HOTPLUG_CPU */ - void scheduler_ipi(void) { - struct rq *rq = this_rq(); - struct task_struct *list = xchg(&rq->wake_list, NULL); - - if (!list) + if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick()) return; /* @@ -2608,25 +2746,21 @@ void scheduler_ipi(void) * somewhat pessimize the simple resched case. */ irq_enter(); - sched_ttwu_do_pending(list); + sched_ttwu_pending(); + + /* + * Check if someone kicked us for doing the nohz idle load balance. + */ + if (unlikely(got_nohz_idle_kick() && !need_resched())) { + this_rq()->idle_balance = 1; + raise_softirq_irqoff(SCHED_SOFTIRQ); + } irq_exit(); } static void ttwu_queue_remote(struct task_struct *p, int cpu) { - struct rq *rq = cpu_rq(cpu); - struct task_struct *next = rq->wake_list; - - for (;;) { - struct task_struct *old = next; - - p->wake_entry = next; - next = cmpxchg(&rq->wake_list, old, p); - if (next == old) - break; - } - - if (!next) + if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) smp_send_reschedule(cpu); } @@ -2848,19 +2982,23 @@ void sched_fork(struct task_struct *p) p->state = TASK_RUNNING; /* + * Make sure we do not leak PI boosting priority to the child. + */ + p->prio = current->normal_prio; + + /* * Revert to default priority/policy on fork if requested. */ if (unlikely(p->sched_reset_on_fork)) { - if (p->policy == SCHED_FIFO || p->policy == SCHED_RR) { + if (task_has_rt_policy(p)) { p->policy = SCHED_NORMAL; - p->normal_prio = p->static_prio; - } - - if (PRIO_TO_NICE(p->static_prio) < 0) { p->static_prio = NICE_TO_PRIO(0); - p->normal_prio = p->static_prio; - set_load_weight(p); - } + p->rt_priority = 0; + } else if (PRIO_TO_NICE(p->static_prio) < 0) + p->static_prio = NICE_TO_PRIO(0); + + p->prio = p->normal_prio = __normal_prio(p); + set_load_weight(p); /* * We don't need the reset flag anymore after the fork. It has @@ -2869,11 +3007,6 @@ void sched_fork(struct task_struct *p) p->sched_reset_on_fork = 0; } - /* - * Make sure we do not leak PI boosting priority to the child. - */ - p->prio = current->normal_prio; - if (!rt_prio(p->prio)) p->sched_class = &fair_sched_class; @@ -3725,30 +3858,6 @@ unsigned long long task_sched_runtime(struct task_struct *p) } /* - * Return sum_exec_runtime for the thread group. - * In case the task is currently running, return the sum plus current's - * pending runtime that have not been accounted yet. - * - * Note that the thread group might have other running tasks as well, - * so the return value not includes other pending runtime that other - * running tasks might have. - */ -unsigned long long thread_group_sched_runtime(struct task_struct *p) -{ - struct task_cputime totals; - unsigned long flags; - struct rq *rq; - u64 ns; - - rq = task_rq_lock(p, &flags); - thread_group_cputime(p, &totals); - ns = totals.sum_exec_runtime + do_task_delta_exec(p, rq); - task_rq_unlock(rq, p, &flags); - - return ns; -} - -/* * Account user cpu time to a process. * @p: the process that the cpu time gets accounted to * @cputime: the cpu time spent in user space since the last update @@ -4140,7 +4249,7 @@ void scheduler_tick(void) perf_event_task_tick(); #ifdef CONFIG_SMP - rq->idle_at_tick = idle_cpu(cpu); + rq->idle_balance = idle_cpu(cpu); trigger_load_balance(rq, cpu); #endif } @@ -4237,6 +4346,7 @@ static inline void schedule_debug(struct task_struct *prev) */ if (unlikely(in_atomic_preempt_off() && !prev->exit_state)) __schedule_bug(prev); + rcu_sleep_check(); profile_hit(SCHED_PROFILING, __builtin_return_address(0)); @@ -4263,7 +4373,7 @@ pick_next_task(struct rq *rq) * Optimization: we know that if all tasks are in * the fair class we can call that function directly: */ - if (likely(rq->nr_running == rq->cfs.nr_running)) { + if (likely(rq->nr_running == rq->cfs.h_nr_running)) { p = fair_sched_class.pick_next_task(rq); if (likely(p)) return p; @@ -4372,7 +4482,7 @@ static inline void sched_submit_work(struct task_struct *tsk) blk_schedule_flush_plug(tsk); } -asmlinkage void schedule(void) +asmlinkage void __sched schedule(void) { struct task_struct *tsk = current; @@ -5049,7 +5159,20 @@ EXPORT_SYMBOL(task_nice); */ int idle_cpu(int cpu) { - return cpu_curr(cpu) == cpu_rq(cpu)->idle; + struct rq *rq = cpu_rq(cpu); + + if (rq->curr != rq->idle) + return 0; + + if (rq->nr_running) + return 0; + +#ifdef CONFIG_SMP + if (!llist_empty(&rq->wake_list)) + return 0; +#endif + + return 1; } /** @@ -5899,7 +6022,7 @@ void show_state_filter(unsigned long state_filter) printk(KERN_INFO " task PC stack pid father\n"); #endif - read_lock(&tasklist_lock); + rcu_read_lock(); do_each_thread(g, p) { /* * reset the NMI-timeout, listing all files on a slow @@ -5915,7 +6038,7 @@ void show_state_filter(unsigned long state_filter) #ifdef CONFIG_SCHED_DEBUG sysrq_sched_debug_show(); #endif - read_unlock(&tasklist_lock); + rcu_read_unlock(); /* * Only show locks if all tasks are dumped: */ @@ -5979,15 +6102,6 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu) } /* - * In a system that switches off the HZ timer nohz_cpu_mask - * indicates which cpus entered this state. This is used - * in the rcu update to wait only for active cpus. For system - * which do not switch off the HZ timer nohz_cpu_mask should - * always be CPU_BITS_NONE. - */ -cpumask_var_t nohz_cpu_mask; - -/* * Increase the granularity value when there are more CPUs, * because with more CPUs the 'effective latency' as visible * to users decreases. But the relationship is not linear, @@ -6039,10 +6153,9 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) { if (p->sched_class && p->sched_class->set_cpus_allowed) p->sched_class->set_cpus_allowed(p, new_mask); - else { - cpumask_copy(&p->cpus_allowed, new_mask); - p->rt.nr_cpus_allowed = cpumask_weight(new_mask); - } + + cpumask_copy(&p->cpus_allowed, new_mask); + p->rt.nr_cpus_allowed = cpumask_weight(new_mask); } /* @@ -6140,7 +6253,7 @@ static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) if (task_cpu(p) != src_cpu) goto done; /* Affinity changed (again). */ - if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed)) + if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) goto fail; /* @@ -6221,6 +6334,30 @@ static void calc_global_load_remove(struct rq *rq) rq->calc_load_active = 0; } +#ifdef CONFIG_CFS_BANDWIDTH +static void unthrottle_offline_cfs_rqs(struct rq *rq) +{ + struct cfs_rq *cfs_rq; + + for_each_leaf_cfs_rq(rq, cfs_rq) { + struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); + + if (!cfs_rq->runtime_enabled) + continue; + + /* + * clock_task is not advancing so we just need to make sure + * there's some valid quota amount + */ + cfs_rq->runtime_remaining = cfs_b->quota; + if (cfs_rq_throttled(cfs_rq)) + unthrottle_cfs_rq(cfs_rq); + } +} +#else +static void unthrottle_offline_cfs_rqs(struct rq *rq) {} +#endif + /* * Migrate all tasks from the rq, sleeping tasks will be migrated by * try_to_wake_up()->select_task_rq(). @@ -6246,6 +6383,9 @@ static void migrate_tasks(unsigned int dead_cpu) */ rq->stop = NULL; + /* Ensure any throttled groups are reachable by pick_next_task */ + unthrottle_offline_cfs_rqs(rq); + for ( ; ; ) { /* * There's this thread running, bail when that's the only @@ -7987,6 +8127,7 @@ static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq, /* allow initial update_cfs_load() to truncate */ cfs_rq->load_stamp = 1; #endif + init_cfs_rq_runtime(cfs_rq); tg->cfs_rq[cpu] = cfs_rq; tg->se[cpu] = se; @@ -8126,6 +8267,7 @@ void __init sched_init(void) * We achieve this by letting root_task_group's tasks sit * directly in rq->cfs (i.e root_task_group->se[] = NULL). */ + init_cfs_bandwidth(&root_task_group.cfs_bandwidth); init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); #endif /* CONFIG_FAIR_GROUP_SCHED */ @@ -8155,7 +8297,6 @@ void __init sched_init(void) rq_attach_root(rq, &def_root_domain); #ifdef CONFIG_NO_HZ rq->nohz_balance_kick = 0; - init_sched_softirq_csd(&per_cpu(remote_sched_softirq_cb, i)); #endif #endif init_rq_hrtick(rq); @@ -8197,8 +8338,6 @@ void __init sched_init(void) */ current->sched_class = &fair_sched_class; - /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */ - zalloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT); #ifdef CONFIG_SMP zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); #ifdef CONFIG_NO_HZ @@ -8228,6 +8367,7 @@ void __might_sleep(const char *file, int line, int preempt_offset) { static unsigned long prev_jiffy; /* ratelimiting */ + rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) || system_state != SYSTEM_RUNNING || oops_in_progress) return; @@ -8367,6 +8507,8 @@ static void free_fair_sched_group(struct task_group *tg) { int i; + destroy_cfs_bandwidth(tg_cfs_bandwidth(tg)); + for_each_possible_cpu(i) { if (tg->cfs_rq) kfree(tg->cfs_rq[i]); @@ -8394,6 +8536,8 @@ int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) tg->shares = NICE_0_LOAD; + init_cfs_bandwidth(tg_cfs_bandwidth(tg)); + for_each_possible_cpu(i) { cfs_rq = kzalloc_node(sizeof(struct cfs_rq), GFP_KERNEL, cpu_to_node(i)); @@ -8669,12 +8813,7 @@ unsigned long sched_group_shares(struct task_group *tg) } #endif -#ifdef CONFIG_RT_GROUP_SCHED -/* - * Ensure that the real time constraints are schedulable. - */ -static DEFINE_MUTEX(rt_constraints_mutex); - +#if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH) static unsigned long to_ratio(u64 period, u64 runtime) { if (runtime == RUNTIME_INF) @@ -8682,6 +8821,13 @@ static unsigned long to_ratio(u64 period, u64 runtime) return div64_u64(runtime << 20, period); } +#endif + +#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) @@ -8702,7 +8848,7 @@ struct rt_schedulable_data { u64 rt_runtime; }; -static int tg_schedulable(struct task_group *tg, void *data) +static int tg_rt_schedulable(struct task_group *tg, void *data) { struct rt_schedulable_data *d = data; struct task_group *child; @@ -8760,16 +8906,22 @@ static int tg_schedulable(struct task_group *tg, void *data) 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, }; - return walk_tg_tree(tg_schedulable, tg_nop, &data); + rcu_read_lock(); + ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); + rcu_read_unlock(); + + return ret; } -static int tg_set_bandwidth(struct task_group *tg, +static int tg_set_rt_bandwidth(struct task_group *tg, u64 rt_period, u64 rt_runtime) { int i, err = 0; @@ -8808,7 +8960,7 @@ int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) if (rt_runtime_us < 0) rt_runtime = RUNTIME_INF; - return tg_set_bandwidth(tg, rt_period, rt_runtime); + return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); } long sched_group_rt_runtime(struct task_group *tg) @@ -8833,7 +8985,7 @@ int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) if (rt_period == 0) return -EINVAL; - return tg_set_bandwidth(tg, rt_period, rt_runtime); + return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); } long sched_group_rt_period(struct task_group *tg) @@ -9023,6 +9175,238 @@ static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft) return (u64) scale_load_down(tg->shares); } + +#ifdef CONFIG_CFS_BANDWIDTH +static DEFINE_MUTEX(cfs_constraints_mutex); + +const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ +const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ + +static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); + +static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) +{ + int i, ret = 0, runtime_enabled; + struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(tg); + + if (tg == &root_task_group) + return -EINVAL; + + /* + * Ensure we have at some amount of bandwidth every period. This is + * to prevent reaching a state of large arrears when throttled via + * entity_tick() resulting in prolonged exit starvation. + */ + if (quota < min_cfs_quota_period || period < min_cfs_quota_period) + return -EINVAL; + + /* + * Likewise, bound things on the otherside by preventing insane quota + * periods. This also allows us to normalize in computing quota + * feasibility. + */ + if (period > max_cfs_quota_period) + return -EINVAL; + + mutex_lock(&cfs_constraints_mutex); + ret = __cfs_schedulable(tg, period, quota); + if (ret) + goto out_unlock; + + runtime_enabled = quota != RUNTIME_INF; + raw_spin_lock_irq(&cfs_b->lock); + cfs_b->period = ns_to_ktime(period); + cfs_b->quota = quota; + + __refill_cfs_bandwidth_runtime(cfs_b); + /* restart the period timer (if active) to handle new period expiry */ + if (runtime_enabled && cfs_b->timer_active) { + /* force a reprogram */ + cfs_b->timer_active = 0; + __start_cfs_bandwidth(cfs_b); + } + raw_spin_unlock_irq(&cfs_b->lock); + + for_each_possible_cpu(i) { + struct cfs_rq *cfs_rq = tg->cfs_rq[i]; + struct rq *rq = rq_of(cfs_rq); + + raw_spin_lock_irq(&rq->lock); + cfs_rq->runtime_enabled = runtime_enabled; + cfs_rq->runtime_remaining = 0; + + if (cfs_rq_throttled(cfs_rq)) + unthrottle_cfs_rq(cfs_rq); + raw_spin_unlock_irq(&rq->lock); + } +out_unlock: + mutex_unlock(&cfs_constraints_mutex); + + return ret; +} + +int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) +{ + u64 quota, period; + + period = ktime_to_ns(tg_cfs_bandwidth(tg)->period); + if (cfs_quota_us < 0) + quota = RUNTIME_INF; + else + quota = (u64)cfs_quota_us * NSEC_PER_USEC; + + return tg_set_cfs_bandwidth(tg, period, quota); +} + +long tg_get_cfs_quota(struct task_group *tg) +{ + u64 quota_us; + + if (tg_cfs_bandwidth(tg)->quota == RUNTIME_INF) + return -1; + + quota_us = tg_cfs_bandwidth(tg)->quota; + do_div(quota_us, NSEC_PER_USEC); + + return quota_us; +} + +int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) +{ + u64 quota, period; + + period = (u64)cfs_period_us * NSEC_PER_USEC; + quota = tg_cfs_bandwidth(tg)->quota; + + if (period <= 0) + return -EINVAL; + + return tg_set_cfs_bandwidth(tg, period, quota); +} + +long tg_get_cfs_period(struct task_group *tg) +{ + u64 cfs_period_us; + + cfs_period_us = ktime_to_ns(tg_cfs_bandwidth(tg)->period); + do_div(cfs_period_us, NSEC_PER_USEC); + + return cfs_period_us; +} + +static s64 cpu_cfs_quota_read_s64(struct cgroup *cgrp, struct cftype *cft) +{ + return tg_get_cfs_quota(cgroup_tg(cgrp)); +} + +static int cpu_cfs_quota_write_s64(struct cgroup *cgrp, struct cftype *cftype, + s64 cfs_quota_us) +{ + return tg_set_cfs_quota(cgroup_tg(cgrp), cfs_quota_us); +} + +static u64 cpu_cfs_period_read_u64(struct cgroup *cgrp, struct cftype *cft) +{ + return tg_get_cfs_period(cgroup_tg(cgrp)); +} + +static int cpu_cfs_period_write_u64(struct cgroup *cgrp, struct cftype *cftype, + u64 cfs_period_us) +{ + return tg_set_cfs_period(cgroup_tg(cgrp), cfs_period_us); +} + +struct cfs_schedulable_data { + struct task_group *tg; + u64 period, quota; +}; + +/* + * normalize group quota/period to be quota/max_period + * note: units are usecs + */ +static u64 normalize_cfs_quota(struct task_group *tg, + struct cfs_schedulable_data *d) +{ + u64 quota, period; + + if (tg == d->tg) { + period = d->period; + quota = d->quota; + } else { + period = tg_get_cfs_period(tg); + quota = tg_get_cfs_quota(tg); + } + + /* note: these should typically be equivalent */ + if (quota == RUNTIME_INF || quota == -1) + return RUNTIME_INF; + + return to_ratio(period, quota); +} + +static int tg_cfs_schedulable_down(struct task_group *tg, void *data) +{ + struct cfs_schedulable_data *d = data; + struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(tg); + s64 quota = 0, parent_quota = -1; + + if (!tg->parent) { + quota = RUNTIME_INF; + } else { + struct cfs_bandwidth *parent_b = tg_cfs_bandwidth(tg->parent); + + quota = normalize_cfs_quota(tg, d); + parent_quota = parent_b->hierarchal_quota; + + /* + * ensure max(child_quota) <= parent_quota, inherit when no + * limit is set + */ + if (quota == RUNTIME_INF) + quota = parent_quota; + else if (parent_quota != RUNTIME_INF && quota > parent_quota) + return -EINVAL; + } + cfs_b->hierarchal_quota = quota; + + return 0; +} + +static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) +{ + int ret; + struct cfs_schedulable_data data = { + .tg = tg, + .period = period, + .quota = quota, + }; + + if (quota != RUNTIME_INF) { + do_div(data.period, NSEC_PER_USEC); + do_div(data.quota, NSEC_PER_USEC); + } + + rcu_read_lock(); + ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); + rcu_read_unlock(); + + return ret; +} + +static int cpu_stats_show(struct cgroup *cgrp, struct cftype *cft, + struct cgroup_map_cb *cb) +{ + struct task_group *tg = cgroup_tg(cgrp); + struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(tg); + + cb->fill(cb, "nr_periods", cfs_b->nr_periods); + cb->fill(cb, "nr_throttled", cfs_b->nr_throttled); + cb->fill(cb, "throttled_time", cfs_b->throttled_time); + + return 0; +} +#endif /* CONFIG_CFS_BANDWIDTH */ #endif /* CONFIG_FAIR_GROUP_SCHED */ #ifdef CONFIG_RT_GROUP_SCHED @@ -9057,6 +9441,22 @@ static struct cftype cpu_files[] = { .write_u64 = cpu_shares_write_u64, }, #endif +#ifdef CONFIG_CFS_BANDWIDTH + { + .name = "cfs_quota_us", + .read_s64 = cpu_cfs_quota_read_s64, + .write_s64 = cpu_cfs_quota_write_s64, + }, + { + .name = "cfs_period_us", + .read_u64 = cpu_cfs_period_read_u64, + .write_u64 = cpu_cfs_period_write_u64, + }, + { + .name = "stat", + .read_map = cpu_stats_show, + }, +#endif #ifdef CONFIG_RT_GROUP_SCHED { .name = "rt_runtime_us", @@ -9366,4 +9766,3 @@ struct cgroup_subsys cpuacct_subsys = { .subsys_id = cpuacct_subsys_id, }; #endif /* CONFIG_CGROUP_CPUACCT */ - |