/* * kernel/sched/core.c * * Kernel scheduler and related syscalls * * Copyright (C) 1991-2002 Linus Torvalds * * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and * make semaphores SMP safe * 1998-11-19 Implemented schedule_timeout() and related stuff * by Andrea Arcangeli * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar: * hybrid priority-list and round-robin design with * an array-switch method of distributing timeslices * and per-CPU runqueues. Cleanups and useful suggestions * by Davide Libenzi, preemptible kernel bits by Robert Love. * 2003-09-03 Interactivity tuning by Con Kolivas. * 2004-04-02 Scheduler domains code by Nick Piggin * 2007-04-15 Work begun on replacing all interactivity tuning with a * fair scheduling design by Con Kolivas. * 2007-05-05 Load balancing (smp-nice) and other improvements * by Peter Williams * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins, * Thomas Gleixner, Mike Kravetz */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_PARAVIRT #include #endif #include "sched.h" #include "../workqueue_internal.h" #include "../smpboot.h" #define CREATE_TRACE_POINTS #include #if defined(CONFIG_AVM_SIMPLE_PROFILING) #include #endif /*--- #if defined(CONFIG_AVM_SIMPLE_PROFILING) ---*/ #if defined(CONFIG_BCM_KF_BUZZZ) && defined(CONFIG_BUZZZ_KEVT) #include #endif void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period) { 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); } } DEFINE_MUTEX(sched_domains_mutex); DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); static void update_rq_clock_task(struct rq *rq, s64 delta); void update_rq_clock(struct rq *rq) { s64 delta; lockdep_assert_held(&rq->lock); if (rq->clock_skip_update & RQCF_ACT_SKIP) return; delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; if (delta < 0) return; rq->clock += delta; update_rq_clock_task(rq, delta); } /* * Debugging: various feature bits */ #define SCHED_FEAT(name, enabled) \ (1UL << __SCHED_FEAT_##name) * enabled | const_debug unsigned int sysctl_sched_features = #include "features.h" 0; #undef SCHED_FEAT #ifdef CONFIG_SCHED_DEBUG #define SCHED_FEAT(name, enabled) \ #name , static const char * const sched_feat_names[] = { #include "features.h" }; #undef SCHED_FEAT static int sched_feat_show(struct seq_file *m, void *v) { int i; for (i = 0; i < __SCHED_FEAT_NR; i++) { if (!(sysctl_sched_features & (1UL << i))) seq_puts(m, "NO_"); seq_printf(m, "%s ", sched_feat_names[i]); } seq_puts(m, "\n"); return 0; } #ifdef HAVE_JUMP_LABEL #define jump_label_key__true STATIC_KEY_INIT_TRUE #define jump_label_key__false STATIC_KEY_INIT_FALSE #define SCHED_FEAT(name, enabled) \ jump_label_key__##enabled , struct static_key sched_feat_keys[__SCHED_FEAT_NR] = { #include "features.h" }; #undef SCHED_FEAT static void sched_feat_disable(int i) { if (static_key_enabled(&sched_feat_keys[i])) static_key_slow_dec(&sched_feat_keys[i]); } static void sched_feat_enable(int i) { if (!static_key_enabled(&sched_feat_keys[i])) static_key_slow_inc(&sched_feat_keys[i]); } #else static void sched_feat_disable(int i) { }; static void sched_feat_enable(int i) { }; #endif /* HAVE_JUMP_LABEL */ static int sched_feat_set(char *cmp) { int i; int neg = 0; if (strncmp(cmp, "NO_", 3) == 0) { neg = 1; cmp += 3; } for (i = 0; i < __SCHED_FEAT_NR; i++) { if (strcmp(cmp, sched_feat_names[i]) == 0) { if (neg) { sysctl_sched_features &= ~(1UL << i); sched_feat_disable(i); } else { sysctl_sched_features |= (1UL << i); sched_feat_enable(i); } break; } } return i; } static ssize_t sched_feat_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { char buf[64]; char *cmp; int i; struct inode *inode; if (cnt > 63) cnt = 63; if (copy_from_user(&buf, ubuf, cnt)) return -EFAULT; buf[cnt] = 0; cmp = strstrip(buf); /* Ensure the static_key remains in a consistent state */ inode = file_inode(filp); mutex_lock(&inode->i_mutex); i = sched_feat_set(cmp); mutex_unlock(&inode->i_mutex); if (i == __SCHED_FEAT_NR) return -EINVAL; *ppos += cnt; return cnt; } static int sched_feat_open(struct inode *inode, struct file *filp) { return single_open(filp, sched_feat_show, NULL); } static const struct file_operations sched_feat_fops = { .open = sched_feat_open, .write = sched_feat_write, .read = seq_read, .llseek = seq_lseek, .release = single_release, }; static __init int sched_init_debug(void) { debugfs_create_file("sched_features", 0644, NULL, NULL, &sched_feat_fops); return 0; } late_initcall(sched_init_debug); #endif /* CONFIG_SCHED_DEBUG */ /* * Number of tasks to iterate in a single balance run. * Limited because this is done with IRQs disabled. */ const_debug unsigned int sysctl_sched_nr_migrate = 32; /* * period over which we average the RT time consumption, measured * in ms. * * default: 1s */ const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC; /* * period over which we measure -rt task cpu usage in us. * default: 1s */ #if defined(CONFIG_BCM_KF_SCHED_RT) && defined(CONFIG_BCM_SCHED_RT_PERIOD) unsigned int sysctl_sched_rt_period = CONFIG_BCM_SCHED_RT_PERIOD; #else unsigned int sysctl_sched_rt_period = 1000000; #endif __read_mostly int scheduler_running; /* * part of the period that we allow rt tasks to run in us. * default: 0.95s */ #if defined(CONFIG_BCM_KF_SCHED_RT) && defined(CONFIG_BCM_SCHED_RT_RUNTIME) /* RT task takes 100% of time */ int sysctl_sched_rt_runtime = CONFIG_BCM_SCHED_RT_RUNTIME; #else int sysctl_sched_rt_runtime = 950000; #endif /* cpus with isolated domains */ cpumask_var_t cpu_isolated_map; /* * this_rq_lock - lock this runqueue and disable interrupts. */ static struct rq *this_rq_lock(void) __acquires(rq->lock) { struct rq *rq; local_irq_disable(); rq = this_rq(); raw_spin_lock(&rq->lock); return rq; } #ifdef CONFIG_SCHED_HRTICK /* * Use HR-timers to deliver accurate preemption points. */ static void hrtick_clear(struct rq *rq) { if (hrtimer_active(&rq->hrtick_timer)) hrtimer_cancel(&rq->hrtick_timer); } /* * High-resolution timer tick. * Runs from hardirq context with interrupts disabled. */ static enum hrtimer_restart hrtick(struct hrtimer *timer) { struct rq *rq = container_of(timer, struct rq, hrtick_timer); WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); #if defined(CONFIG_BCM_KF_BUZZZ) && defined(CONFIG_BUZZZ_KEVT) BUZZZ_KNL3(SCHED_HRTICK, 0, 0); #endif raw_spin_lock(&rq->lock); update_rq_clock(rq); rq->curr->sched_class->task_tick(rq, rq->curr, 1); raw_spin_unlock(&rq->lock); return HRTIMER_NORESTART; } #ifdef CONFIG_SMP static int __hrtick_restart(struct rq *rq) { struct hrtimer *timer = &rq->hrtick_timer; ktime_t time = hrtimer_get_softexpires(timer); return __hrtimer_start_range_ns(timer, time, 0, HRTIMER_MODE_ABS_PINNED, 0); } /* * called from hardirq (IPI) context */ static void __hrtick_start(void *arg) { struct rq *rq = arg; raw_spin_lock(&rq->lock); __hrtick_restart(rq); rq->hrtick_csd_pending = 0; raw_spin_unlock(&rq->lock); } /* * Called to set the hrtick timer state. * * called with rq->lock held and irqs disabled */ void hrtick_start(struct rq *rq, u64 delay) { struct hrtimer *timer = &rq->hrtick_timer; ktime_t time; s64 delta; /* * Don't schedule slices shorter than 10000ns, that just * doesn't make sense and can cause timer DoS. */ delta = max_t(s64, delay, 10000LL); time = ktime_add_ns(timer->base->get_time(), delta); hrtimer_set_expires(timer, time); if (rq == this_rq()) { __hrtick_restart(rq); } else if (!rq->hrtick_csd_pending) { smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd); rq->hrtick_csd_pending = 1; } } static int hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu) { int cpu = (int)(long)hcpu; switch (action) { case CPU_UP_CANCELED: case CPU_UP_CANCELED_FROZEN: case CPU_DOWN_PREPARE: case CPU_DOWN_PREPARE_FROZEN: case CPU_DEAD: case CPU_DEAD_FROZEN: hrtick_clear(cpu_rq(cpu)); return NOTIFY_OK; } return NOTIFY_DONE; } static __init void init_hrtick(void) { hotcpu_notifier(hotplug_hrtick, 0); } #else /* * Called to set the hrtick timer state. * * called with rq->lock held and irqs disabled */ void hrtick_start(struct rq *rq, u64 delay) { /* * Don't schedule slices shorter than 10000ns, that just * doesn't make sense. Rely on vruntime for fairness. */ delay = max_t(u64, delay, 10000LL); __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0, HRTIMER_MODE_REL_PINNED, 0); } static inline void init_hrtick(void) { } #endif /* CONFIG_SMP */ static void init_rq_hrtick(struct rq *rq) { #ifdef CONFIG_SMP rq->hrtick_csd_pending = 0; rq->hrtick_csd.flags = 0; rq->hrtick_csd.func = __hrtick_start; rq->hrtick_csd.info = rq; #endif hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); rq->hrtick_timer.function = hrtick; } #else /* CONFIG_SCHED_HRTICK */ static inline void hrtick_clear(struct rq *rq) { } static inline void init_rq_hrtick(struct rq *rq) { } static inline void init_hrtick(void) { } #endif /* CONFIG_SCHED_HRTICK */ /* * cmpxchg based fetch_or, macro so it works for different integer types */ #define fetch_or(ptr, val) \ ({ typeof(*(ptr)) __old, __val = *(ptr); \ for (;;) { \ __old = cmpxchg((ptr), __val, __val | (val)); \ if (__old == __val) \ break; \ __val = __old; \ } \ __old; \ }) #if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG) /* * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG, * this avoids any races wrt polling state changes and thereby avoids * spurious IPIs. */ static bool set_nr_and_not_polling(struct task_struct *p) { struct thread_info *ti = task_thread_info(p); return !(fetch_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLAG); } /* * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set. * * If this returns true, then the idle task promises to call * sched_ttwu_pending() and reschedule soon. */ static bool set_nr_if_polling(struct task_struct *p) { struct thread_info *ti = task_thread_info(p); typeof(ti->flags) old, val = ACCESS_ONCE(ti->flags); for (;;) { if (!(val & _TIF_POLLING_NRFLAG)) return false; if (val & _TIF_NEED_RESCHED) return true; old = cmpxchg(&ti->flags, val, val | _TIF_NEED_RESCHED); if (old == val) break; val = old; } return true; } #else static bool set_nr_and_not_polling(struct task_struct *p) { set_tsk_need_resched(p); return true; } #ifdef CONFIG_SMP static bool set_nr_if_polling(struct task_struct *p) { return false; } #endif #endif /* * resched_curr - mark rq's current task 'to be rescheduled now'. * * On UP this means the setting of the need_resched flag, on SMP it * might also involve a cross-CPU call to trigger the scheduler on * the target CPU. */ void resched_curr(struct rq *rq) { struct task_struct *curr = rq->curr; int cpu; lockdep_assert_held(&rq->lock); if (test_tsk_need_resched(curr)) return; cpu = cpu_of(rq); if (cpu == smp_processor_id()) { set_tsk_need_resched(curr); set_preempt_need_resched(); return; } if (set_nr_and_not_polling(curr)) smp_send_reschedule(cpu); else trace_sched_wake_idle_without_ipi(cpu); } void resched_cpu(int cpu) { struct rq *rq = cpu_rq(cpu); unsigned long flags; raw_spin_lock_irqsave(&rq->lock, flags); if (cpu_online(cpu) || cpu == smp_processor_id()) resched_curr(rq); raw_spin_unlock_irqrestore(&rq->lock, flags); } #ifdef CONFIG_SMP #ifdef CONFIG_NO_HZ_COMMON /* * In the semi idle case, use the nearest busy cpu for migrating timers * from an idle cpu. This is good for power-savings. * * We don't do similar optimization for completely idle system, as * selecting an idle cpu will add more delays to the timers than intended * (as that cpu's timer base may not be uptodate wrt jiffies etc). */ int get_nohz_timer_target(int pinned) { int cpu = smp_processor_id(); int i; struct sched_domain *sd; if (pinned || !get_sysctl_timer_migration() || !idle_cpu(cpu)) return cpu; rcu_read_lock(); for_each_domain(cpu, sd) { for_each_cpu(i, sched_domain_span(sd)) { if (!idle_cpu(i)) { cpu = i; goto unlock; } } } unlock: rcu_read_unlock(); return cpu; } /* * When add_timer_on() enqueues a timer into the timer wheel of an * idle CPU then this timer might expire before the next timer event * which is scheduled to wake up that CPU. In case of a completely * idle system the next event might even be infinite time into the * future. wake_up_idle_cpu() ensures that the CPU is woken up and * leaves the inner idle loop so the newly added timer is taken into * account when the CPU goes back to idle and evaluates the timer * wheel for the next timer event. */ static void wake_up_idle_cpu(int cpu) { struct rq *rq = cpu_rq(cpu); if (cpu == smp_processor_id()) return; if (set_nr_and_not_polling(rq->idle)) smp_send_reschedule(cpu); else trace_sched_wake_idle_without_ipi(cpu); } static bool wake_up_full_nohz_cpu(int cpu) { /* * We just need the target to call irq_exit() and re-evaluate * the next tick. The nohz full kick at least implies that. * If needed we can still optimize that later with an * empty IRQ. */ if (tick_nohz_full_cpu(cpu)) { if (cpu != smp_processor_id() || tick_nohz_tick_stopped()) tick_nohz_full_kick_cpu(cpu); return true; } return false; } void wake_up_nohz_cpu(int cpu) { if (!wake_up_full_nohz_cpu(cpu)) wake_up_idle_cpu(cpu); } static inline bool got_nohz_idle_kick(void) { int cpu = smp_processor_id(); if (!test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu))) return false; if (idle_cpu(cpu) && !need_resched()) return true; /* * We can't run Idle Load Balance on this CPU for this time so we * cancel it and clear NOHZ_BALANCE_KICK */ clear_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)); return false; } #else /* CONFIG_NO_HZ_COMMON */ static inline bool got_nohz_idle_kick(void) { return false; } #endif /* CONFIG_NO_HZ_COMMON */ #ifdef CONFIG_NO_HZ_FULL bool sched_can_stop_tick(void) { /* * FIFO realtime policy runs the highest priority task. Other runnable * tasks are of a lower priority. The scheduler tick does nothing. */ if (current->policy == SCHED_FIFO) return true; /* * Round-robin realtime tasks time slice with other tasks at the same * realtime priority. Is this task the only one at this priority? */ if (current->policy == SCHED_RR) { struct sched_rt_entity *rt_se = ¤t->rt; return rt_se->run_list.prev == rt_se->run_list.next; } /* * More than one running task need preemption. * nr_running update is assumed to be visible * after IPI is sent from wakers. */ if (this_rq()->nr_running > 1) return false; return true; } #endif /* CONFIG_NO_HZ_FULL */ void sched_avg_update(struct rq *rq) { s64 period = sched_avg_period(); while ((s64)(rq_clock(rq) - rq->age_stamp) > period) { /* * Inline assembly required to prevent the compiler * optimising this loop into a divmod call. * See __iter_div_u64_rem() for another example of this. */ asm("" : "+rm" (rq->age_stamp)); rq->age_stamp += period; rq->rt_avg /= 2; } } #endif /* CONFIG_SMP */ #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \ (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH))) /* * 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. */ int walk_tg_tree_from(struct task_group *from, tg_visitor down, tg_visitor up, void *data) { struct task_group *parent, *child; int ret; parent = from; down: ret = (*down)(parent, data); if (ret) goto out; list_for_each_entry_rcu(child, &parent->children, siblings) { parent = child; goto down; up: continue; } ret = (*up)(parent, data); if (ret || parent == from) goto out; child = parent; parent = parent->parent; if (parent) goto up; out: return ret; } int tg_nop(struct task_group *tg, void *data) { return 0; } #endif static void set_load_weight(struct task_struct *p) { int prio = p->static_prio - MAX_RT_PRIO; struct load_weight *load = &p->se.load; /* * SCHED_IDLE tasks get minimal weight: */ if (p->policy == SCHED_IDLE) { load->weight = scale_load(WEIGHT_IDLEPRIO); load->inv_weight = WMULT_IDLEPRIO; return; } load->weight = scale_load(prio_to_weight[prio]); load->inv_weight = prio_to_wmult[prio]; } static void enqueue_task(struct rq *rq, struct task_struct *p, int flags) { update_rq_clock(rq); sched_info_queued(rq, p); p->sched_class->enqueue_task(rq, p, flags); } static void dequeue_task(struct rq *rq, struct task_struct *p, int flags) { update_rq_clock(rq); sched_info_dequeued(rq, p); p->sched_class->dequeue_task(rq, p, flags); } void activate_task(struct rq *rq, struct task_struct *p, int flags) { if (task_contributes_to_load(p)) rq->nr_uninterruptible--; enqueue_task(rq, p, flags); } void deactivate_task(struct rq *rq, struct task_struct *p, int flags) { if (task_contributes_to_load(p)) rq->nr_uninterruptible++; dequeue_task(rq, p, flags); } static void update_rq_clock_task(struct rq *rq, s64 delta) { /* * In theory, the compile should just see 0 here, and optimize out the call * to sched_rt_avg_update. But I don't trust it... */ #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) s64 steal = 0, irq_delta = 0; #endif #ifdef CONFIG_IRQ_TIME_ACCOUNTING irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; /* * Since irq_time is only updated on {soft,}irq_exit, we might run into * this case when a previous update_rq_clock() happened inside a * {soft,}irq region. * * When this happens, we stop ->clock_task and only update the * prev_irq_time stamp to account for the part that fit, so that a next * update will consume the rest. This ensures ->clock_task is * monotonic. * * It does however cause some slight miss-attribution of {soft,}irq * time, a more accurate solution would be to update the irq_time using * the current rq->clock timestamp, except that would require using * atomic ops. */ if (irq_delta > delta) irq_delta = delta; rq->prev_irq_time += irq_delta; delta -= irq_delta; #endif #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING if (static_key_false((¶virt_steal_rq_enabled))) { steal = paravirt_steal_clock(cpu_of(rq)); steal -= rq->prev_steal_time_rq; if (unlikely(steal > delta)) steal = delta; rq->prev_steal_time_rq += steal; delta -= steal; } #endif rq->clock_task += delta; #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) if ((irq_delta + steal) && sched_feat(NONTASK_CAPACITY)) sched_rt_avg_update(rq, irq_delta + steal); #endif } void sched_set_stop_task(int cpu, struct task_struct *stop) { struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; struct task_struct *old_stop = cpu_rq(cpu)->stop; if (stop) { /* * Make it appear like a SCHED_FIFO task, its something * userspace knows about and won't get confused about. * * Also, it will make PI more or less work without too * much confusion -- but then, stop work should not * rely on PI working anyway. */ sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m); stop->sched_class = &stop_sched_class; } cpu_rq(cpu)->stop = stop; if (old_stop) { /* * Reset it back to a normal scheduling class so that * it can die in pieces. */ old_stop->sched_class = &rt_sched_class; } } /* * __normal_prio - return the priority that is based on the static prio */ static inline int __normal_prio(struct task_struct *p) { return p->static_prio; } /* * Calculate the expected normal priority: i.e. priority * without taking RT-inheritance into account. Might be * boosted by interactivity modifiers. Changes upon fork, * setprio syscalls, and whenever the interactivity * estimator recalculates. */ static inline int normal_prio(struct task_struct *p) { int prio; if (task_has_dl_policy(p)) prio = MAX_DL_PRIO-1; else if (task_has_rt_policy(p)) prio = MAX_RT_PRIO-1 - p->rt_priority; else prio = __normal_prio(p); return prio; } /* * Calculate the current priority, i.e. the priority * taken into account by the scheduler. This value might * be boosted by RT tasks, or might be boosted by * interactivity modifiers. Will be RT if the task got * RT-boosted. If not then it returns p->normal_prio. */ static int effective_prio(struct task_struct *p) { p->normal_prio = normal_prio(p); /* * If we are RT tasks or we were boosted to RT priority, * keep the priority unchanged. Otherwise, update priority * to the normal priority: */ if (!rt_prio(p->prio)) return p->normal_prio; return p->prio; } /** * task_curr - is this task currently executing on a CPU? * @p: the task in question. * * Return: 1 if the task is currently executing. 0 otherwise. */ inline int task_curr(const struct task_struct *p) { return cpu_curr(task_cpu(p)) == p; } /* * Can drop rq->lock because from sched_class::switched_from() methods drop it. */ static inline void check_class_changed(struct rq *rq, struct task_struct *p, const struct sched_class *prev_class, int oldprio) { if (prev_class != p->sched_class) { if (prev_class->switched_from) prev_class->switched_from(rq, p); /* Possble rq->lock 'hole'. */ p->sched_class->switched_to(rq, p); } else if (oldprio != p->prio || dl_task(p)) p->sched_class->prio_changed(rq, p, oldprio); } void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) { const struct sched_class *class; if (p->sched_class == rq->curr->sched_class) { rq->curr->sched_class->check_preempt_curr(rq, p, flags); } else { for_each_class(class) { if (class == rq->curr->sched_class) break; if (class == p->sched_class) { resched_curr(rq); break; } } } /* * A queue event has occurred, and we're going to schedule. In * this case, we can save a useless back to back clock update. */ if (task_on_rq_queued(rq->curr) && test_tsk_need_resched(rq->curr)) rq_clock_skip_update(rq, true); } #ifdef CONFIG_SMP void set_task_cpu(struct task_struct *p, unsigned int new_cpu) { #ifdef CONFIG_SCHED_DEBUG /* * We should never call set_task_cpu() on a blocked task, * ttwu() will sort out the placement. */ WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && !p->on_rq); #ifdef CONFIG_LOCKDEP /* * The caller should hold either p->pi_lock or rq->lock, when changing * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. * * sched_move_task() holds both and thus holding either pins the cgroup, * see task_group(). * * Furthermore, all task_rq users should acquire both locks, see * task_rq_lock(). */ WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || lockdep_is_held(&task_rq(p)->lock))); #endif #endif trace_sched_migrate_task(p, new_cpu); if (task_cpu(p) != new_cpu) { if (p->sched_class->migrate_task_rq) p->sched_class->migrate_task_rq(p, new_cpu); p->se.nr_migrations++; perf_sw_event_sched(PERF_COUNT_SW_CPU_MIGRATIONS, 1, 0); } __set_task_cpu(p, new_cpu); } static void __migrate_swap_task(struct task_struct *p, int cpu) { if (task_on_rq_queued(p)) { struct rq *src_rq, *dst_rq; src_rq = task_rq(p); dst_rq = cpu_rq(cpu); deactivate_task(src_rq, p, 0); set_task_cpu(p, cpu); activate_task(dst_rq, p, 0); check_preempt_curr(dst_rq, p, 0); } else { /* * Task isn't running anymore; make it appear like we migrated * it before it went to sleep. This means on wakeup we make the * previous cpu our targer instead of where it really is. */ p->wake_cpu = cpu; } } struct migration_swap_arg { struct task_struct *src_task, *dst_task; int src_cpu, dst_cpu; }; static int migrate_swap_stop(void *data) { struct migration_swap_arg *arg = data; struct rq *src_rq, *dst_rq; int ret = -EAGAIN; src_rq = cpu_rq(arg->src_cpu); dst_rq = cpu_rq(arg->dst_cpu); double_raw_lock(&arg->src_task->pi_lock, &arg->dst_task->pi_lock); double_rq_lock(src_rq, dst_rq); if (task_cpu(arg->dst_task) != arg->dst_cpu) goto unlock; if (task_cpu(arg->src_task) != arg->src_cpu) goto unlock; if (!cpumask_test_cpu(arg->dst_cpu, tsk_cpus_allowed(arg->src_task))) goto unlock; if (!cpumask_test_cpu(arg->src_cpu, tsk_cpus_allowed(arg->dst_task))) goto unlock; __migrate_swap_task(arg->src_task, arg->dst_cpu); __migrate_swap_task(arg->dst_task, arg->src_cpu); ret = 0; unlock: double_rq_unlock(src_rq, dst_rq); raw_spin_unlock(&arg->dst_task->pi_lock); raw_spin_unlock(&arg->src_task->pi_lock); return ret; } /* * Cross migrate two tasks */ int migrate_swap(struct task_struct *cur, struct task_struct *p) { struct migration_swap_arg arg; int ret = -EINVAL; arg = (struct migration_swap_arg){ .src_task = cur, .src_cpu = task_cpu(cur), .dst_task = p, .dst_cpu = task_cpu(p), }; if (arg.src_cpu == arg.dst_cpu) goto out; /* * These three tests are all lockless; this is OK since all of them * will be re-checked with proper locks held further down the line. */ if (!cpu_active(arg.src_cpu) || !cpu_active(arg.dst_cpu)) goto out; if (!cpumask_test_cpu(arg.dst_cpu, tsk_cpus_allowed(arg.src_task))) goto out; if (!cpumask_test_cpu(arg.src_cpu, tsk_cpus_allowed(arg.dst_task))) goto out; trace_sched_swap_numa(cur, arg.src_cpu, p, arg.dst_cpu); ret = stop_two_cpus(arg.dst_cpu, arg.src_cpu, migrate_swap_stop, &arg); out: return ret; } struct migration_arg { struct task_struct *task; int dest_cpu; }; static int migration_cpu_stop(void *data); /* * wait_task_inactive - wait for a thread to unschedule. * * If @match_state is nonzero, it's the @p->state value just checked and * not expected to change. If it changes, i.e. @p might have woken up, * then return zero. When we succeed in waiting for @p to be off its CPU, * we return a positive number (its total switch count). If a second call * a short while later returns the same number, the caller can be sure that * @p has remained unscheduled the whole time. * * The caller must ensure that the task *will* unschedule sometime soon, * else this function might spin for a *long* time. This function can't * be called with interrupts off, or it may introduce deadlock with * smp_call_function() if an IPI is sent by the same process we are * waiting to become inactive. */ unsigned long wait_task_inactive(struct task_struct *p, long match_state) { unsigned long flags; int running, queued; unsigned long ncsw; struct rq *rq; for (;;) { /* * We do the initial early heuristics without holding * any task-queue locks at all. We'll only try to get * the runqueue lock when things look like they will * work out! */ rq = task_rq(p); /* * If the task is actively running on another CPU * still, just relax and busy-wait without holding * any locks. * * NOTE! Since we don't hold any locks, it's not * even sure that "rq" stays as the right runqueue! * But we don't care, since "task_running()" will * return false if the runqueue has changed and p * is actually now running somewhere else! */ while (task_running(rq, p)) { if (match_state && unlikely(p->state != match_state)) return 0; cpu_relax(); } /* * Ok, time to look more closely! We need the rq * lock now, to be *sure*. If we're wrong, we'll * just go back and repeat. */ rq = task_rq_lock(p, &flags); trace_sched_wait_task(p); running = task_running(rq, p); queued = task_on_rq_queued(p); ncsw = 0; if (!match_state || p->state == match_state) ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ task_rq_unlock(rq, p, &flags); /* * If it changed from the expected state, bail out now. */ if (unlikely(!ncsw)) break; /* * Was it really running after all now that we * checked with the proper locks actually held? * * Oops. Go back and try again.. */ if (unlikely(running)) { cpu_relax(); continue; } /* * It's not enough that it's not actively running, * it must be off the runqueue _entirely_, and not * preempted! * * So if it was still runnable (but just not actively * running right now), it's preempted, and we should * yield - it could be a while. */ if (unlikely(queued)) { ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ); set_current_state(TASK_UNINTERRUPTIBLE); schedule_hrtimeout(&to, HRTIMER_MODE_REL); continue; } /* * Ahh, all good. It wasn't running, and it wasn't * runnable, which means that it will never become * running in the future either. We're all done! */ break; } return ncsw; } /*** * kick_process - kick a running thread to enter/exit the kernel * @p: the to-be-kicked thread * * Cause a process which is running on another CPU to enter * kernel-mode, without any delay. (to get signals handled.) * * NOTE: this function doesn't have to take the runqueue lock, * because all it wants to ensure is that the remote task enters * the kernel. If the IPI races and the task has been migrated * to another CPU then no harm is done and the purpose has been * achieved as well. */ void kick_process(struct task_struct *p) { int cpu; preempt_disable(); cpu = task_cpu(p); if ((cpu != smp_processor_id()) && task_curr(p)) smp_send_reschedule(cpu); preempt_enable(); } EXPORT_SYMBOL_GPL(kick_process); #endif /* CONFIG_SMP */ #ifdef CONFIG_SMP /* * ->cpus_allowed is protected by both rq->lock and p->pi_lock */ static int select_fallback_rq(int cpu, struct task_struct *p) { int nid = cpu_to_node(cpu); const struct cpumask *nodemask = NULL; enum { cpuset, possible, fail } state = cpuset; int dest_cpu; #if defined(CONFIG_BCM_KF_CPU_AFFINITY_HINT) && \ defined(CONFIG_BCM_PROC_CPU_AFFINITY_HINT) struct cpumask cpus_valid; int v; #endif /* * If the node that the cpu is on has been offlined, cpu_to_node() * will return -1. There is no cpu on the node, and we should * select the cpu on the other node. */ if (nid != -1) { nodemask = cpumask_of_node(nid); #if defined(CONFIG_BCM_KF_CPU_AFFINITY_HINT) && \ defined(CONFIG_BCM_PROC_CPU_AFFINITY_HINT) /* * As cpu_active_mask is always a subset of cpu_online_mask, * any CPU on this node which is also active and allowed could * be selected as the dest_cpu. We prefer such CPU which is * in addition hinted, if it exists. * * valid = (node & active & allowed); * if (valid) { * if (valid & hint) { * recover allowed as hint; * return dest_cpu = any_of(valid & hint); * } * return dest_cpu = any_of(valid); * } * goto try_other_nodes; */ v = cpumask_and(&cpus_valid, nodemask, cpu_active_mask) && cpumask_and(&cpus_valid, &cpus_valid, tsk_cpus_allowed(p)); if (v) { dest_cpu = cpumask_any_and(&cpus_valid, &p->cpus_hint); if (dest_cpu < nr_cpu_ids) { do_set_cpus_allowed(p, &p->cpus_hint); return dest_cpu; } return cpumask_any(&cpus_valid); } #else /* Look for allowed, online CPU in same node. */ for_each_cpu(dest_cpu, nodemask) { if (!cpu_online(dest_cpu)) continue; if (!cpu_active(dest_cpu)) continue; if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) return dest_cpu; } #endif } for (;;) { #if defined(CONFIG_BCM_KF_CPU_AFFINITY_HINT) && \ defined(CONFIG_BCM_PROC_CPU_AFFINITY_HINT) if (p->flags & PF_KTHREAD) { /* * Kernel threads can be scheduled to run on online * CPUs, even if the CPU is not active. * * valid = (allowed & online); */ v = cpumask_and(&cpus_valid, tsk_cpus_allowed(p), cpu_online_mask); } else { /* * User-space threads must be scheduled to active CPUs. * * valid = (allowed & active); */ v = cpumask_and(&cpus_valid, tsk_cpus_allowed(p), cpu_active_mask); } dest_cpu = v ? cpumask_any_and(&cpus_valid, &p->cpus_hint) : nr_cpu_ids; if (dest_cpu < nr_cpu_ids) { /* recover allowed as hint; */ do_set_cpus_allowed(p, &p->cpus_hint); goto out; /* return dest_cpu = any_of(valid & hint); */ } dest_cpu = v ? cpumask_any(&cpus_valid) : nr_cpu_ids; if (dest_cpu < nr_cpu_ids) goto out; /* return dest_cpu = any_of(valid); */ #else /* Any allowed, online CPU? */ for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) { if (!cpu_online(dest_cpu)) continue; if (!cpu_active(dest_cpu)) continue; goto out; } #endif switch (state) { case cpuset: /* No more Mr. Nice Guy. */ cpuset_cpus_allowed_fallback(p); state = possible; break; case possible: do_set_cpus_allowed(p, cpu_possible_mask); state = fail; break; case fail: BUG(); break; } } out: if (state != cpuset) { /* * Don't tell them about moving exiting tasks or * kernel threads (both mm NULL), since they never * leave kernel. */ if (p->mm && printk_ratelimit()) { printk_deferred("process %d (%s) no longer affine to cpu%d\n", task_pid_nr(p), p->comm, cpu); } } return dest_cpu; } #if defined(CONFIG_BCM_KF_CPU_AFFINITY_HINT) && \ defined(CONFIG_BCM_PROC_CPU_AFFINITY_HINT) /* * Called by select_task_rq() when the selected cpu is allowed and online to * decide whether select_fallback_rq() should be called to replace the * selected allowed online cpu with some active/online allowed hinted CPU. * * Return 0 (i.e., no need to try to replace the selected allowed online cpu) * if: * 1. no active/online hinted CPU, or * 2. the selected cpu is one of the active/online hinted CPUs, or * 3. all the active/online hinted CPUs are not allowed now. * * Condition 3 exists because do_set_cpus_allowed() is also called by * cpuset_cpus_allowed_fallback() in kernel/cpuset.c and __kthread_bind() in * kernel/kthread.c, except for cases in this kernel/sched/core.c. It may be * called at more places in the future kernels too. However, only for the case * of set_cpus_allowed_ptr(), we copy cpus_allowed into cpus_hint after * calling do_set_cpus_allowed(). */ static int try_valid_cpu_hint(int cpu, struct task_struct *p) { struct cpumask cpus_valid; int v; if (p->flags & PF_KTHREAD) v = cpumask_and(&cpus_valid, &p->cpus_hint, cpu_online_mask); else v = cpumask_and(&cpus_valid, &p->cpus_hint, cpu_active_mask); if (!v || cpumask_test_cpu(cpu, &cpus_valid)) return 0; return cpumask_intersects(&cpus_valid, tsk_cpus_allowed(p)); } #endif /* * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. */ static inline int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags) { if (p->nr_cpus_allowed > 1) cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags); #if defined(CONFIG_BCM_KF_CPU_AFFINITY_HINT) && \ defined(CONFIG_BCM_PROC_CPU_AFFINITY_HINT) else /* This improvement is back-ported from recent kernel. */ cpu = cpumask_any(tsk_cpus_allowed(p)); #endif /* * In order not to call set_task_cpu() on a blocking task we need * to rely on ttwu() to place the task on a valid ->cpus_allowed * cpu. * * Since this is common to all placement strategies, this lives here. * * [ this allows ->select_task() to simply return task_cpu(p) and * not worry about this generic constraint ] */ if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) || #if defined(CONFIG_BCM_KF_CPU_AFFINITY_HINT) && \ defined(CONFIG_BCM_PROC_CPU_AFFINITY_HINT) !cpu_online(cpu) || try_valid_cpu_hint(cpu, p))) #else !cpu_online(cpu))) #endif cpu = select_fallback_rq(task_cpu(p), p); return cpu; } static void update_avg(u64 *avg, u64 sample) { s64 diff = sample - *avg; *avg += diff >> 3; } #endif static void ttwu_stat(struct task_struct *p, int cpu, int wake_flags) { #ifdef CONFIG_SCHEDSTATS struct rq *rq = this_rq(); #ifdef CONFIG_SMP int this_cpu = smp_processor_id(); if (cpu == this_cpu) { schedstat_inc(rq, ttwu_local); schedstat_inc(p, se.statistics.nr_wakeups_local); } else { struct sched_domain *sd; schedstat_inc(p, se.statistics.nr_wakeups_remote); rcu_read_lock(); for_each_domain(this_cpu, sd) { if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { schedstat_inc(sd, ttwu_wake_remote); break; } } rcu_read_unlock(); } if (wake_flags & WF_MIGRATED) schedstat_inc(p, se.statistics.nr_wakeups_migrate); #endif /* CONFIG_SMP */ schedstat_inc(rq, ttwu_count); schedstat_inc(p, se.statistics.nr_wakeups); if (wake_flags & WF_SYNC) schedstat_inc(p, se.statistics.nr_wakeups_sync); #endif /* CONFIG_SCHEDSTATS */ } static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) { activate_task(rq, p, en_flags); p->on_rq = TASK_ON_RQ_QUEUED; /* if a worker is waking up, notify workqueue */ if (p->flags & PF_WQ_WORKER) wq_worker_waking_up(p, cpu_of(rq)); } /* * Mark the task runnable and perform wakeup-preemption. */ static void ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) { check_preempt_curr(rq, p, wake_flags); trace_sched_wakeup(p, true); p->state = TASK_RUNNING; #ifdef CONFIG_SMP if (p->sched_class->task_woken) p->sched_class->task_woken(rq, p); if (rq->idle_stamp) { u64 delta = rq_clock(rq) - rq->idle_stamp; u64 max = 2*rq->max_idle_balance_cost; update_avg(&rq->avg_idle, delta); if (rq->avg_idle > max) rq->avg_idle = max; rq->idle_stamp = 0; } #endif } static void ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) { #ifdef CONFIG_SMP if (p->sched_contributes_to_load) rq->nr_uninterruptible--; #endif ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); ttwu_do_wakeup(rq, p, wake_flags); } /* * Called in case the task @p isn't fully descheduled from its runqueue, * in this case we must do a remote wakeup. Its a 'light' wakeup though, * since all we need to do is flip p->state to TASK_RUNNING, since * the task is still ->on_rq. */ static int ttwu_remote(struct task_struct *p, int wake_flags) { struct rq *rq; int ret = 0; rq = __task_rq_lock(p); if (task_on_rq_queued(p)) { /* check_preempt_curr() may use rq clock */ update_rq_clock(rq); ttwu_do_wakeup(rq, p, wake_flags); ret = 1; } __task_rq_unlock(rq); return ret; } #ifdef CONFIG_SMP void sched_ttwu_pending(void) { struct rq *rq = this_rq(); struct llist_node *llist = llist_del_all(&rq->wake_list); struct task_struct *p; unsigned long flags; if (!llist) return; raw_spin_lock_irqsave(&rq->lock, flags); while (llist) { p = llist_entry(llist, struct task_struct, wake_entry); llist = llist_next(llist); ttwu_do_activate(rq, p, 0); } raw_spin_unlock_irqrestore(&rq->lock, flags); } void scheduler_ipi(void) { /* * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting * TIF_NEED_RESCHED remotely (for the first time) will also send * this IPI. */ preempt_fold_need_resched(); if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick()) return; /* * Not all reschedule IPI handlers call irq_enter/irq_exit, since * traditionally all their work was done from the interrupt return * path. Now that we actually do some work, we need to make sure * we do call them. * * Some archs already do call them, luckily irq_enter/exit nest * properly. * * Arguably we should visit all archs and update all handlers, * however a fair share of IPIs are still resched only so this would * somewhat pessimize the simple resched case. */ irq_enter(); sched_ttwu_pending(); /* * Check if someone kicked us for doing the nohz idle load balance. */ if (unlikely(got_nohz_idle_kick())) { 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); if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) { if (!set_nr_if_polling(rq->idle)) smp_send_reschedule(cpu); else trace_sched_wake_idle_without_ipi(cpu); } } void wake_up_if_idle(int cpu) { struct rq *rq = cpu_rq(cpu); unsigned long flags; rcu_read_lock(); if (!is_idle_task(rcu_dereference(rq->curr))) goto out; if (set_nr_if_polling(rq->idle)) { trace_sched_wake_idle_without_ipi(cpu); } else { raw_spin_lock_irqsave(&rq->lock, flags); if (is_idle_task(rq->curr)) smp_send_reschedule(cpu); /* Else cpu is not in idle, do nothing here */ raw_spin_unlock_irqrestore(&rq->lock, flags); } out: rcu_read_unlock(); } bool cpus_share_cache(int this_cpu, int that_cpu) { return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); } #endif /* CONFIG_SMP */ static void ttwu_queue(struct task_struct *p, int cpu) { struct rq *rq = cpu_rq(cpu); #if defined(CONFIG_SMP) if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) { sched_clock_cpu(cpu); /* sync clocks x-cpu */ ttwu_queue_remote(p, cpu); return; } #endif raw_spin_lock(&rq->lock); ttwu_do_activate(rq, p, 0); raw_spin_unlock(&rq->lock); } /** * try_to_wake_up - wake up a thread * @p: the thread to be awakened * @state: the mask of task states that can be woken * @wake_flags: wake modifier flags (WF_*) * * Put it on the run-queue if it's not already there. The "current" * thread is always on the run-queue (except when the actual * re-schedule is in progress), and as such you're allowed to do * the simpler "current->state = TASK_RUNNING" to mark yourself * runnable without the overhead of this. * * Return: %true if @p was woken up, %false if it was already running. * or @state didn't match @p's state. */ static int try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) { unsigned long flags; int cpu, success = 0; /* * If we are going to wake up a thread waiting for CONDITION we * need to ensure that CONDITION=1 done by the caller can not be * reordered with p->state check below. This pairs with mb() in * set_current_state() the waiting thread does. */ smp_mb__before_spinlock(); raw_spin_lock_irqsave(&p->pi_lock, flags); if (!(p->state & state)) goto out; success = 1; /* we're going to change ->state */ cpu = task_cpu(p); /* * Ensure we load p->on_rq _after_ p->state, otherwise it would * be possible to, falsely, observe p->on_rq == 0 and get stuck * in smp_cond_load_acquire() below. * * sched_ttwu_pending() try_to_wake_up() * [S] p->on_rq = 1; [L] P->state * UNLOCK rq->lock -----. * \ * +--- RMB * schedule() / * LOCK rq->lock -----' * UNLOCK rq->lock * * [task p] * [S] p->state = UNINTERRUPTIBLE [L] p->on_rq * * Pairs with the UNLOCK+LOCK on rq->lock from the * last wakeup of our task and the schedule that got our task * current. */ smp_rmb(); if (p->on_rq && ttwu_remote(p, wake_flags)) goto stat; #ifdef CONFIG_SMP /* * If the owning (remote) cpu is still in the middle of schedule() with * this task as prev, wait until its done referencing the task. */ while (p->on_cpu) cpu_relax(); /* * Pairs with the smp_wmb() in finish_lock_switch(). */ smp_rmb(); p->sched_contributes_to_load = !!task_contributes_to_load(p); p->state = TASK_WAKING; if (p->sched_class->task_waking) p->sched_class->task_waking(p); cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags); if (task_cpu(p) != cpu) { wake_flags |= WF_MIGRATED; set_task_cpu(p, cpu); } #endif /* CONFIG_SMP */ ttwu_queue(p, cpu); stat: ttwu_stat(p, cpu, wake_flags); out: raw_spin_unlock_irqrestore(&p->pi_lock, flags); return success; } /** * try_to_wake_up_local - try to wake up a local task with rq lock held * @p: the thread to be awakened * * Put @p on the run-queue if it's not already there. The caller must * ensure that this_rq() is locked, @p is bound to this_rq() and not * the current task. */ static void try_to_wake_up_local(struct task_struct *p) { struct rq *rq = task_rq(p); if (WARN_ON_ONCE(rq != this_rq()) || WARN_ON_ONCE(p == current)) return; lockdep_assert_held(&rq->lock); if (!raw_spin_trylock(&p->pi_lock)) { raw_spin_unlock(&rq->lock); raw_spin_lock(&p->pi_lock); raw_spin_lock(&rq->lock); } if (!(p->state & TASK_NORMAL)) goto out; if (!task_on_rq_queued(p)) ttwu_activate(rq, p, ENQUEUE_WAKEUP); ttwu_do_wakeup(rq, p, 0); ttwu_stat(p, smp_processor_id(), 0); out: raw_spin_unlock(&p->pi_lock); } /** * wake_up_process - Wake up a specific process * @p: The process to be woken up. * * Attempt to wake up the nominated process and move it to the set of runnable * processes. * * Return: 1 if the process was woken up, 0 if it was already running. * * It may be assumed that this function implies a write memory barrier before * changing the task state if and only if any tasks are woken up. */ int wake_up_process(struct task_struct *p) { WARN_ON(task_is_stopped_or_traced(p)); return try_to_wake_up(p, TASK_NORMAL, 0); } EXPORT_SYMBOL(wake_up_process); int wake_up_state(struct task_struct *p, unsigned int state) { return try_to_wake_up(p, state, 0); } /* * This function clears the sched_dl_entity static params. */ void __dl_clear_params(struct task_struct *p) { struct sched_dl_entity *dl_se = &p->dl; dl_se->dl_runtime = 0; dl_se->dl_deadline = 0; dl_se->dl_period = 0; dl_se->flags = 0; dl_se->dl_bw = 0; dl_se->dl_throttled = 0; dl_se->dl_new = 1; dl_se->dl_yielded = 0; } /* * Perform scheduler related setup for a newly forked process p. * p is forked by current. * * __sched_fork() is basic setup used by init_idle() too: */ static void __sched_fork(unsigned long clone_flags, struct task_struct *p) { p->on_rq = 0; p->se.on_rq = 0; p->se.exec_start = 0; p->se.sum_exec_runtime = 0; p->se.prev_sum_exec_runtime = 0; p->se.nr_migrations = 0; p->se.vruntime = 0; #ifdef CONFIG_SMP p->se.avg.decay_count = 0; #endif INIT_LIST_HEAD(&p->se.group_node); #ifdef CONFIG_SCHEDSTATS memset(&p->se.statistics, 0, sizeof(p->se.statistics)); #endif RB_CLEAR_NODE(&p->dl.rb_node); init_dl_task_timer(&p->dl); __dl_clear_params(p); INIT_LIST_HEAD(&p->rt.run_list); #ifdef CONFIG_PREEMPT_NOTIFIERS INIT_HLIST_HEAD(&p->preempt_notifiers); #endif #ifdef CONFIG_NUMA_BALANCING if (p->mm && atomic_read(&p->mm->mm_users) == 1) { p->mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay); p->mm->numa_scan_seq = 0; } if (clone_flags & CLONE_VM) p->numa_preferred_nid = current->numa_preferred_nid; else p->numa_preferred_nid = -1; p->node_stamp = 0ULL; p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0; p->numa_scan_period = sysctl_numa_balancing_scan_delay; p->numa_work.next = &p->numa_work; p->numa_faults = NULL; p->last_task_numa_placement = 0; p->last_sum_exec_runtime = 0; p->numa_group = NULL; #endif /* CONFIG_NUMA_BALANCING */ } #ifdef CONFIG_NUMA_BALANCING #ifdef CONFIG_SCHED_DEBUG void set_numabalancing_state(bool enabled) { if (enabled) sched_feat_set("NUMA"); else sched_feat_set("NO_NUMA"); } #else __read_mostly bool numabalancing_enabled; void set_numabalancing_state(bool enabled) { numabalancing_enabled = enabled; } #endif /* CONFIG_SCHED_DEBUG */ #ifdef CONFIG_PROC_SYSCTL int sysctl_numa_balancing(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { struct ctl_table t; int err; int state = numabalancing_enabled; if (write && !capable(CAP_SYS_ADMIN)) return -EPERM; t = *table; t.data = &state; err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); if (err < 0) return err; if (write) set_numabalancing_state(state); return err; } #endif #endif /* * fork()/clone()-time setup: */ int sched_fork(unsigned long clone_flags, struct task_struct *p) { unsigned long flags; int cpu = get_cpu(); __sched_fork(clone_flags, p); /* * We mark the process as running here. This guarantees that * nobody will actually run it, and a signal or other external * event cannot wake it up and insert it on the runqueue either. */ 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 (task_has_dl_policy(p) || task_has_rt_policy(p)) { p->policy = SCHED_NORMAL; p->static_prio = NICE_TO_PRIO(0); 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 * fulfilled its duty: */ p->sched_reset_on_fork = 0; } if (dl_prio(p->prio)) { put_cpu(); return -EAGAIN; } else if (rt_prio(p->prio)) { p->sched_class = &rt_sched_class; } else { p->sched_class = &fair_sched_class; } if (p->sched_class->task_fork) p->sched_class->task_fork(p); /* * The child is not yet in the pid-hash so no cgroup attach races, * and the cgroup is pinned to this child due to cgroup_fork() * is ran before sched_fork(). * * Silence PROVE_RCU. */ raw_spin_lock_irqsave(&p->pi_lock, flags); set_task_cpu(p, cpu); raw_spin_unlock_irqrestore(&p->pi_lock, flags); #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) if (likely(sched_info_on())) memset(&p->sched_info, 0, sizeof(p->sched_info)); #endif #if defined(CONFIG_SMP) p->on_cpu = 0; #endif init_task_preempt_count(p); #ifdef CONFIG_SMP plist_node_init(&p->pushable_tasks, MAX_PRIO); RB_CLEAR_NODE(&p->pushable_dl_tasks); #endif put_cpu(); return 0; } unsigned long to_ratio(u64 period, u64 runtime) { if (runtime == RUNTIME_INF) return 1ULL << 20; /* * Doing this here saves a lot of checks in all * the calling paths, and returning zero seems * safe for them anyway. */ if (period == 0) return 0; return div64_u64(runtime << 20, period); } #ifdef CONFIG_SMP inline struct dl_bw *dl_bw_of(int i) { rcu_lockdep_assert(rcu_read_lock_sched_held(), "sched RCU must be held"); return &cpu_rq(i)->rd->dl_bw; } static inline int dl_bw_cpus(int i) { struct root_domain *rd = cpu_rq(i)->rd; int cpus = 0; rcu_lockdep_assert(rcu_read_lock_sched_held(), "sched RCU must be held"); for_each_cpu_and(i, rd->span, cpu_active_mask) cpus++; return cpus; } #else inline struct dl_bw *dl_bw_of(int i) { return &cpu_rq(i)->dl.dl_bw; } static inline int dl_bw_cpus(int i) { return 1; } #endif /* * We must be sure that accepting a new task (or allowing changing the * parameters of an existing one) is consistent with the bandwidth * constraints. If yes, this function also accordingly updates the currently * allocated bandwidth to reflect the new situation. * * This function is called while holding p's rq->lock. * * XXX we should delay bw change until the task's 0-lag point, see * __setparam_dl(). */ static int dl_overflow(struct task_struct *p, int policy, const struct sched_attr *attr) { struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); u64 period = attr->sched_period ?: attr->sched_deadline; u64 runtime = attr->sched_runtime; u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0; int cpus, err = -1; if (new_bw == p->dl.dl_bw) return 0; /* * Either if a task, enters, leave, or stays -deadline but changes * its parameters, we may need to update accordingly the total * allocated bandwidth of the container. */ raw_spin_lock(&dl_b->lock); cpus = dl_bw_cpus(task_cpu(p)); if (dl_policy(policy) && !task_has_dl_policy(p) && !__dl_overflow(dl_b, cpus, 0, new_bw)) { __dl_add(dl_b, new_bw); err = 0; } else if (dl_policy(policy) && task_has_dl_policy(p) && !__dl_overflow(dl_b, cpus, p->dl.dl_bw, new_bw)) { __dl_clear(dl_b, p->dl.dl_bw); __dl_add(dl_b, new_bw); err = 0; } else if (!dl_policy(policy) && task_has_dl_policy(p)) { __dl_clear(dl_b, p->dl.dl_bw); err = 0; } raw_spin_unlock(&dl_b->lock); return err; } extern void init_dl_bw(struct dl_bw *dl_b); /* * wake_up_new_task - wake up a newly created task for the first time. * * This function will do some initial scheduler statistics housekeeping * that must be done for every newly created context, then puts the task * on the runqueue and wakes it. */ void wake_up_new_task(struct task_struct *p) { unsigned long flags; struct rq *rq; raw_spin_lock_irqsave(&p->pi_lock, flags); #ifdef CONFIG_SMP /* * Fork balancing, do it here and not earlier because: * - cpus_allowed can change in the fork path * - any previously selected cpu might disappear through hotplug */ set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0)); #endif /* Initialize new task's runnable average */ init_task_runnable_average(p); rq = __task_rq_lock(p); activate_task(rq, p, 0); p->on_rq = TASK_ON_RQ_QUEUED; trace_sched_wakeup_new(p, true); check_preempt_curr(rq, p, WF_FORK); #ifdef CONFIG_SMP if (p->sched_class->task_woken) p->sched_class->task_woken(rq, p); #endif task_rq_unlock(rq, p, &flags); } #ifdef CONFIG_PREEMPT_NOTIFIERS /** * preempt_notifier_register - tell me when current is being preempted & rescheduled * @notifier: notifier struct to register */ void preempt_notifier_register(struct preempt_notifier *notifier) { hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); } EXPORT_SYMBOL_GPL(preempt_notifier_register); /** * preempt_notifier_unregister - no longer interested in preemption notifications * @notifier: notifier struct to unregister * * This is safe to call from within a preemption notifier. */ void preempt_notifier_unregister(struct preempt_notifier *notifier) { hlist_del(¬ifier->link); } EXPORT_SYMBOL_GPL(preempt_notifier_unregister); static void fire_sched_in_preempt_notifiers(struct task_struct *curr) { struct preempt_notifier *notifier; hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) notifier->ops->sched_in(notifier, raw_smp_processor_id()); } static void fire_sched_out_preempt_notifiers(struct task_struct *curr, struct task_struct *next) { struct preempt_notifier *notifier; hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) notifier->ops->sched_out(notifier, next); } #else /* !CONFIG_PREEMPT_NOTIFIERS */ static void fire_sched_in_preempt_notifiers(struct task_struct *curr) { } static void fire_sched_out_preempt_notifiers(struct task_struct *curr, struct task_struct *next) { } #endif /* CONFIG_PREEMPT_NOTIFIERS */ /** * prepare_task_switch - prepare to switch tasks * @rq: the runqueue preparing to switch * @prev: the current task that is being switched out * @next: the task we are going to switch to. * * This is called with the rq lock held and interrupts off. It must * be paired with a subsequent finish_task_switch after the context * switch. * * prepare_task_switch sets up locking and calls architecture specific * hooks. */ static inline void prepare_task_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next) { trace_sched_switch(prev, next); sched_info_switch(rq, prev, next); perf_event_task_sched_out(prev, next); fire_sched_out_preempt_notifiers(prev, next); prepare_lock_switch(rq, next); prepare_arch_switch(next); } /** * finish_task_switch - clean up after a task-switch * @prev: the thread we just switched away from. * * finish_task_switch must be called after the context switch, paired * with a prepare_task_switch call before the context switch. * finish_task_switch will reconcile locking set up by prepare_task_switch, * and do any other architecture-specific cleanup actions. * * Note that we may have delayed dropping an mm in context_switch(). If * so, we finish that here outside of the runqueue lock. (Doing it * with the lock held can cause deadlocks; see schedule() for * details.) * * The context switch have flipped the stack from under us and restored the * local variables which were saved when this task called schedule() in the * past. prev == current is still correct but we need to recalculate this_rq * because prev may have moved to another CPU. */ static struct rq *finish_task_switch(struct task_struct *prev) __releases(rq->lock) { struct rq *rq = this_rq(); struct mm_struct *mm = rq->prev_mm; long prev_state; rq->prev_mm = NULL; /* * A task struct has one reference for the use as "current". * If a task dies, then it sets TASK_DEAD in tsk->state and calls * schedule one last time. The schedule call will never return, and * the scheduled task must drop that reference. * * We must observe prev->state before clearing prev->on_cpu (in * finish_lock_switch), otherwise a concurrent wakeup can get prev * running on another CPU and we could rave with its RUNNING -> DEAD * transition, resulting in a double drop. */ prev_state = prev->state; #if defined(CONFIG_AVM_SIMPLE_PROFILING) avm_simple_profiling_sched(); #endif /*--- #if defined(CONFIG_AVM_SIMPLE_PROFILING) ---*/ vtime_task_switch(prev); finish_arch_switch(prev); perf_event_task_sched_in(prev, current); finish_lock_switch(rq, prev); finish_arch_post_lock_switch(); fire_sched_in_preempt_notifiers(current); if (mm) mmdrop(mm); if (unlikely(prev_state == TASK_DEAD)) { if (prev->sched_class->task_dead) prev->sched_class->task_dead(prev); /* * Remove function-return probe instances associated with this * task and put them back on the free list. */ kprobe_flush_task(prev); put_task_struct(prev); } tick_nohz_task_switch(current); return rq; } #ifdef CONFIG_SMP /* rq->lock is NOT held, but preemption is disabled */ static inline void post_schedule(struct rq *rq) { if (rq->post_schedule) { unsigned long flags; raw_spin_lock_irqsave(&rq->lock, flags); if (rq->curr->sched_class->post_schedule) rq->curr->sched_class->post_schedule(rq); raw_spin_unlock_irqrestore(&rq->lock, flags); rq->post_schedule = 0; } } #else static inline void post_schedule(struct rq *rq) { } #endif /** * schedule_tail - first thing a freshly forked thread must call. * @prev: the thread we just switched away from. */ asmlinkage __visible void schedule_tail(struct task_struct *prev) __releases(rq->lock) { struct rq *rq; /* finish_task_switch() drops rq->lock and enables preemtion */ preempt_disable(); rq = finish_task_switch(prev); post_schedule(rq); preempt_enable(); if (current->set_child_tid) put_user(task_pid_vnr(current), current->set_child_tid); } /* * context_switch - switch to the new MM and the new thread's register state. */ static inline struct rq * context_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next) { struct mm_struct *mm, *oldmm; prepare_task_switch(rq, prev, next); mm = next->mm; oldmm = prev->active_mm; /* * For paravirt, this is coupled with an exit in switch_to to * combine the page table reload and the switch backend into * one hypercall. */ arch_start_context_switch(prev); if (!mm) { next->active_mm = oldmm; atomic_inc(&oldmm->mm_count); enter_lazy_tlb(oldmm, next); } else switch_mm_irqs_off(oldmm, mm, next); if (!prev->mm) { prev->active_mm = NULL; rq->prev_mm = oldmm; } /* * Since the runqueue lock will be released by the next * task (which is an invalid locking op but in the case * of the scheduler it's an obvious special-case), so we * do an early lockdep release here: */ spin_release(&rq->lock.dep_map, 1, _THIS_IP_); context_tracking_task_switch(prev, next); /* Here we just switch the register state and the stack. */ switch_to(prev, next, prev); barrier(); return finish_task_switch(prev); } /* * nr_running and nr_context_switches: * * externally visible scheduler statistics: current number of runnable * threads, total number of context switches performed since bootup. */ unsigned long nr_running(void) { unsigned long i, sum = 0; for_each_online_cpu(i) sum += cpu_rq(i)->nr_running; return sum; } /* * Check if only the current task is running on the cpu. * * Caution: this function does not check that the caller has disabled * preemption, thus the result might have a time-of-check-to-time-of-use * race. The caller is responsible to use it correctly, for example: * * - from a non-preemptable section (of course) * * - from a thread that is bound to a single CPU * * - in a loop with very short iterations (e.g. a polling loop) */ bool single_task_running(void) { return raw_rq()->nr_running == 1; } EXPORT_SYMBOL(single_task_running); unsigned long long nr_context_switches(void) { int i; unsigned long long sum = 0; for_each_possible_cpu(i) sum += cpu_rq(i)->nr_switches; return sum; } unsigned long nr_iowait(void) { unsigned long i, sum = 0; for_each_possible_cpu(i) sum += atomic_read(&cpu_rq(i)->nr_iowait); return sum; } unsigned long nr_iowait_cpu(int cpu) { struct rq *this = cpu_rq(cpu); return atomic_read(&this->nr_iowait); } void get_iowait_load(unsigned long *nr_waiters, unsigned long *load) { struct rq *this = this_rq(); *nr_waiters = atomic_read(&this->nr_iowait); *load = this->cpu_load[0]; } #ifdef CONFIG_SMP /* * sched_exec - execve() is a valuable balancing opportunity, because at * this point the task has the smallest effective memory and cache footprint. */ void sched_exec(void) { struct task_struct *p = current; unsigned long flags; int dest_cpu; raw_spin_lock_irqsave(&p->pi_lock, flags); dest_cpu = p->sched_class->select_task_rq(p, task_cpu(p), SD_BALANCE_EXEC, 0); if (dest_cpu == smp_processor_id()) goto unlock; if (likely(cpu_active(dest_cpu))) { struct migration_arg arg = { p, dest_cpu }; raw_spin_unlock_irqrestore(&p->pi_lock, flags); stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); return; } unlock: raw_spin_unlock_irqrestore(&p->pi_lock, flags); } #endif DEFINE_PER_CPU(struct kernel_stat, kstat); DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); EXPORT_PER_CPU_SYMBOL(kstat); EXPORT_PER_CPU_SYMBOL(kernel_cpustat); /* * Return accounted runtime for the task. * In case the task is currently running, return the runtime plus current's * pending runtime that have not been accounted yet. */ unsigned long long task_sched_runtime(struct task_struct *p) { unsigned long flags; struct rq *rq; u64 ns; #if defined(CONFIG_64BIT) && defined(CONFIG_SMP) /* * 64-bit doesn't need locks to atomically read a 64bit value. * So we have a optimization chance when the task's delta_exec is 0. * Reading ->on_cpu is racy, but this is ok. * * If we race with it leaving cpu, we'll take a lock. So we're correct. * If we race with it entering cpu, unaccounted time is 0. This is * indistinguishable from the read occurring a few cycles earlier. * If we see ->on_cpu without ->on_rq, the task is leaving, and has * been accounted, so we're correct here as well. */ if (!p->on_cpu || !task_on_rq_queued(p)) return p->se.sum_exec_runtime; #endif rq = task_rq_lock(p, &flags); /* * Must be ->curr _and_ ->on_rq. If dequeued, we would * project cycles that may never be accounted to this * thread, breaking clock_gettime(). */ if (task_current(rq, p) && task_on_rq_queued(p)) { update_rq_clock(rq); p->sched_class->update_curr(rq); } ns = p->se.sum_exec_runtime; task_rq_unlock(rq, p, &flags); return ns; } /* * This function gets called by the timer code, with HZ frequency. * We call it with interrupts disabled. */ void scheduler_tick(void) { int cpu = smp_processor_id(); struct rq *rq = cpu_rq(cpu); struct task_struct *curr = rq->curr; #if defined(CONFIG_BCM_KF_BUZZZ) && defined(CONFIG_BUZZZ_KEVT) BUZZZ_KNL3(SCHED_TICK, jiffies, 0); #endif sched_clock_tick(); raw_spin_lock(&rq->lock); update_rq_clock(rq); curr->sched_class->task_tick(rq, curr, 0); update_cpu_load_active(rq); raw_spin_unlock(&rq->lock); perf_event_task_tick(); #ifdef CONFIG_SMP rq->idle_balance = idle_cpu(cpu); trigger_load_balance(rq); #endif rq_last_tick_reset(rq); } #ifdef CONFIG_NO_HZ_FULL /** * scheduler_tick_max_deferment * * Keep at least one tick per second when a single * active task is running because the scheduler doesn't * yet completely support full dynticks environment. * * This makes sure that uptime, CFS vruntime, load * balancing, etc... continue to move forward, even * with a very low granularity. * * Return: Maximum deferment in nanoseconds. */ u64 scheduler_tick_max_deferment(void) { struct rq *rq = this_rq(); unsigned long next, now = ACCESS_ONCE(jiffies); next = rq->last_sched_tick + HZ; if (time_before_eq(next, now)) return 0; return jiffies_to_nsecs(next - now); } #endif notrace unsigned long get_parent_ip(unsigned long addr) { if (in_lock_functions(addr)) { addr = CALLER_ADDR2; if (in_lock_functions(addr)) addr = CALLER_ADDR3; } return addr; } #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ defined(CONFIG_PREEMPT_TRACER)) void preempt_count_add(int val) { #ifdef CONFIG_DEBUG_PREEMPT /* * Underflow? */ if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) return; #endif __preempt_count_add(val); #ifdef CONFIG_DEBUG_PREEMPT /* * Spinlock count overflowing soon? */ DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK - 10); #endif if (preempt_count() == val) { unsigned long ip = get_parent_ip(CALLER_ADDR1); #ifdef CONFIG_DEBUG_PREEMPT current->preempt_disable_ip = ip; #endif trace_preempt_off(CALLER_ADDR0, ip); } } EXPORT_SYMBOL(preempt_count_add); NOKPROBE_SYMBOL(preempt_count_add); void preempt_count_sub(int val) { #ifdef CONFIG_DEBUG_PREEMPT /* * Underflow? */ if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) return; /* * Is the spinlock portion underflowing? */ if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && !(preempt_count() & PREEMPT_MASK))) return; #endif if (preempt_count() == val) trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); __preempt_count_sub(val); } EXPORT_SYMBOL(preempt_count_sub); NOKPROBE_SYMBOL(preempt_count_sub); #endif /* * Print scheduling while atomic bug: */ static noinline void __schedule_bug(struct task_struct *prev) { if (oops_in_progress) return; printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", prev->comm, prev->pid, preempt_count()); debug_show_held_locks(prev); print_modules(); if (irqs_disabled()) print_irqtrace_events(prev); #ifdef CONFIG_DEBUG_PREEMPT if (in_atomic_preempt_off()) { pr_err("Preemption disabled at:"); print_ip_sym(current->preempt_disable_ip); pr_cont("\n"); } #endif dump_stack(); add_taint(TAINT_WARN, LOCKDEP_STILL_OK); } /* * Various schedule()-time debugging checks and statistics: */ static inline void schedule_debug(struct task_struct *prev) { #ifdef CONFIG_SCHED_STACK_END_CHECK BUG_ON(unlikely(task_stack_end_corrupted(prev))); #endif /* * Test if we are atomic. Since do_exit() needs to call into * schedule() atomically, we ignore that path. Otherwise whine * if we are scheduling when we should not. */ if (unlikely(in_atomic_preempt_off() && prev->state != TASK_DEAD)) __schedule_bug(prev); rcu_sleep_check(); profile_hit(SCHED_PROFILING, __builtin_return_address(0)); schedstat_inc(this_rq(), sched_count); } /* * Pick up the highest-prio task: */ static inline struct task_struct * pick_next_task(struct rq *rq, struct task_struct *prev) { const struct sched_class *class = &fair_sched_class; struct task_struct *p; /* * Optimization: we know that if all tasks are in * the fair class we can call that function directly: */ if (likely(prev->sched_class == class && rq->nr_running == rq->cfs.h_nr_running)) { p = fair_sched_class.pick_next_task(rq, prev); if (unlikely(p == RETRY_TASK)) goto again; /* assumes fair_sched_class->next == idle_sched_class */ if (unlikely(!p)) p = idle_sched_class.pick_next_task(rq, prev); return p; } again: for_each_class(class) { p = class->pick_next_task(rq, prev); if (p) { if (unlikely(p == RETRY_TASK)) goto again; return p; } } BUG(); /* the idle class will always have a runnable task */ } /* * __schedule() is the main scheduler function. * * The main means of driving the scheduler and thus entering this function are: * * 1. Explicit blocking: mutex, semaphore, waitqueue, etc. * * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return * paths. For example, see arch/x86/entry_64.S. * * To drive preemption between tasks, the scheduler sets the flag in timer * interrupt handler scheduler_tick(). * * 3. Wakeups don't really cause entry into schedule(). They add a * task to the run-queue and that's it. * * Now, if the new task added to the run-queue preempts the current * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets * called on the nearest possible occasion: * * - If the kernel is preemptible (CONFIG_PREEMPT=y): * * - in syscall or exception context, at the next outmost * preempt_enable(). (this might be as soon as the wake_up()'s * spin_unlock()!) * * - in IRQ context, return from interrupt-handler to * preemptible context * * - If the kernel is not preemptible (CONFIG_PREEMPT is not set) * then at the next: * * - cond_resched() call * - explicit schedule() call * - return from syscall or exception to user-space * - return from interrupt-handler to user-space * * WARNING: all callers must re-check need_resched() afterward and reschedule * accordingly in case an event triggered the need for rescheduling (such as * an interrupt waking up a task) while preemption was disabled in __schedule(). */ static void __sched __schedule(void) { struct task_struct *prev, *next; unsigned long *switch_count; struct rq *rq; int cpu; preempt_disable(); cpu = smp_processor_id(); rq = cpu_rq(cpu); rcu_note_context_switch(); prev = rq->curr; schedule_debug(prev); if (sched_feat(HRTICK)) hrtick_clear(rq); /* * Make sure that signal_pending_state()->signal_pending() below * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE) * done by the caller to avoid the race with signal_wake_up(). */ smp_mb__before_spinlock(); raw_spin_lock_irq(&rq->lock); rq->clock_skip_update <<= 1; /* promote REQ to ACT */ switch_count = &prev->nivcsw; if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { if (unlikely(signal_pending_state(prev->state, prev))) { prev->state = TASK_RUNNING; } else { deactivate_task(rq, prev, DEQUEUE_SLEEP); prev->on_rq = 0; /* * If a worker went to sleep, notify and ask workqueue * whether it wants to wake up a task to maintain * concurrency. */ if (prev->flags & PF_WQ_WORKER) { struct task_struct *to_wakeup; to_wakeup = wq_worker_sleeping(prev, cpu); if (to_wakeup) try_to_wake_up_local(to_wakeup); } } switch_count = &prev->nvcsw; } if (task_on_rq_queued(prev)) update_rq_clock(rq); next = pick_next_task(rq, prev); clear_tsk_need_resched(prev); clear_preempt_need_resched(); rq->clock_skip_update = 0; if (likely(prev != next)) { rq->nr_switches++; rq->curr = next; ++*switch_count; #if defined(CONFIG_BCM_KF_BUZZZ) && defined(CONFIG_BUZZZ_KEVT) BUZZZ_KNL3(TASK_OUT, prev->pid, prev); BUZZZ_KNL3(TASK_IN, next->pid, next); #endif rq = context_switch(rq, prev, next); /* unlocks the rq */ cpu = cpu_of(rq); } else raw_spin_unlock_irq(&rq->lock); post_schedule(rq); sched_preempt_enable_no_resched(); } static inline void sched_submit_work(struct task_struct *tsk) { if (!tsk->state || tsk_is_pi_blocked(tsk)) return; /* * If we are going to sleep and we have plugged IO queued, * make sure to submit it to avoid deadlocks. */ if (blk_needs_flush_plug(tsk)) blk_schedule_flush_plug(tsk); } asmlinkage __visible void __sched schedule(void) { struct task_struct *tsk = current; sched_submit_work(tsk); do { __schedule(); } while (need_resched()); } EXPORT_SYMBOL(schedule); #ifdef CONFIG_CONTEXT_TRACKING asmlinkage __visible void __sched schedule_user(void) { /* * If we come here after a random call to set_need_resched(), * or we have been woken up remotely but the IPI has not yet arrived, * we haven't yet exited the RCU idle mode. Do it here manually until * we find a better solution. * * NB: There are buggy callers of this function. Ideally we * should warn if prev_state != CONTEXT_USER, but that will trigger * too frequently to make sense yet. */ enum ctx_state prev_state = exception_enter(); schedule(); exception_exit(prev_state); } #endif /** * schedule_preempt_disabled - called with preemption disabled * * Returns with preemption disabled. Note: preempt_count must be 1 */ void __sched schedule_preempt_disabled(void) { sched_preempt_enable_no_resched(); schedule(); preempt_disable(); } static void __sched notrace preempt_schedule_common(void) { do { __preempt_count_add(PREEMPT_ACTIVE); __schedule(); __preempt_count_sub(PREEMPT_ACTIVE); /* * Check again in case we missed a preemption opportunity * between schedule and now. */ barrier(); } while (need_resched()); } #ifdef CONFIG_PREEMPT /* * this is the entry point to schedule() from in-kernel preemption * off of preempt_enable. Kernel preemptions off return from interrupt * occur there and call schedule directly. */ asmlinkage __visible void __sched notrace preempt_schedule(void) { /* * If there is a non-zero preempt_count or interrupts are disabled, * we do not want to preempt the current task. Just return.. */ if (likely(!preemptible())) return; preempt_schedule_common(); } NOKPROBE_SYMBOL(preempt_schedule); EXPORT_SYMBOL(preempt_schedule); #ifdef CONFIG_CONTEXT_TRACKING /** * preempt_schedule_context - preempt_schedule called by tracing * * The tracing infrastructure uses preempt_enable_notrace to prevent * recursion and tracing preempt enabling caused by the tracing * infrastructure itself. But as tracing can happen in areas coming * from userspace or just about to enter userspace, a preempt enable * can occur before user_exit() is called. This will cause the scheduler * to be called when the system is still in usermode. * * To prevent this, the preempt_enable_notrace will use this function * instead of preempt_schedule() to exit user context if needed before * calling the scheduler. */ asmlinkage __visible void __sched notrace preempt_schedule_context(void) { enum ctx_state prev_ctx; if (likely(!preemptible())) return; do { __preempt_count_add(PREEMPT_ACTIVE); /* * Needs preempt disabled in case user_exit() is traced * and the tracer calls preempt_enable_notrace() causing * an infinite recursion. */ prev_ctx = exception_enter(); __schedule(); exception_exit(prev_ctx); __preempt_count_sub(PREEMPT_ACTIVE); barrier(); } while (need_resched()); } EXPORT_SYMBOL_GPL(preempt_schedule_context); #endif /* CONFIG_CONTEXT_TRACKING */ #endif /* CONFIG_PREEMPT */ /* * this is the entry point to schedule() from kernel preemption * off of irq context. * Note, that this is called and return with irqs disabled. This will * protect us against recursive calling from irq. */ asmlinkage __visible void __sched preempt_schedule_irq(void) { enum ctx_state prev_state; /* Catch callers which need to be fixed */ BUG_ON(preempt_count() || !irqs_disabled()); prev_state = exception_enter(); do { __preempt_count_add(PREEMPT_ACTIVE); local_irq_enable(); __schedule(); local_irq_disable(); __preempt_count_sub(PREEMPT_ACTIVE); /* * Check again in case we missed a preemption opportunity * between schedule and now. */ barrier(); } while (need_resched()); exception_exit(prev_state); } int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, void *key) { return try_to_wake_up(curr->private, mode, wake_flags); } EXPORT_SYMBOL(default_wake_function); #ifdef CONFIG_RT_MUTEXES /* * rt_mutex_setprio - set the current priority of a task * @p: task * @prio: prio value (kernel-internal form) * * This function changes the 'effective' priority of a task. It does * not touch ->normal_prio like __setscheduler(). * * Used by the rt_mutex code to implement priority inheritance * logic. Call site only calls if the priority of the task changed. */ void rt_mutex_setprio(struct task_struct *p, int prio) { int oldprio, queued, running, enqueue_flag = 0; struct rq *rq; const struct sched_class *prev_class; BUG_ON(prio > MAX_PRIO); rq = __task_rq_lock(p); /* * Idle task boosting is a nono in general. There is one * exception, when PREEMPT_RT and NOHZ is active: * * The idle task calls get_next_timer_interrupt() and holds * the timer wheel base->lock on the CPU and another CPU wants * to access the timer (probably to cancel it). We can safely * ignore the boosting request, as the idle CPU runs this code * with interrupts disabled and will complete the lock * protected section without being interrupted. So there is no * real need to boost. */ if (unlikely(p == rq->idle)) { WARN_ON(p != rq->curr); WARN_ON(p->pi_blocked_on); goto out_unlock; } trace_sched_pi_setprio(p, prio); oldprio = p->prio; prev_class = p->sched_class; queued = task_on_rq_queued(p); running = task_current(rq, p); if (queued) dequeue_task(rq, p, 0); if (running) put_prev_task(rq, p); /* * Boosting condition are: * 1. -rt task is running and holds mutex A * --> -dl task blocks on mutex A * * 2. -dl task is running and holds mutex A * --> -dl task blocks on mutex A and could preempt the * running task */ if (dl_prio(prio)) { struct task_struct *pi_task = rt_mutex_get_top_task(p); if (!dl_prio(p->normal_prio) || (pi_task && dl_entity_preempt(&pi_task->dl, &p->dl))) { p->dl.dl_boosted = 1; p->dl.dl_throttled = 0; enqueue_flag = ENQUEUE_REPLENISH; } else p->dl.dl_boosted = 0; p->sched_class = &dl_sched_class; } else if (rt_prio(prio)) { if (dl_prio(oldprio)) p->dl.dl_boosted = 0; if (oldprio < prio) enqueue_flag = ENQUEUE_HEAD; p->sched_class = &rt_sched_class; } else { if (dl_prio(oldprio)) p->dl.dl_boosted = 0; if (rt_prio(oldprio)) p->rt.timeout = 0; p->sched_class = &fair_sched_class; } p->prio = prio; if (running) p->sched_class->set_curr_task(rq); if (queued) enqueue_task(rq, p, enqueue_flag); check_class_changed(rq, p, prev_class, oldprio); out_unlock: __task_rq_unlock(rq); } #endif void set_user_nice(struct task_struct *p, long nice) { int old_prio, delta, queued; unsigned long flags; struct rq *rq; if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE) return; /* * We have to be careful, if called from sys_setpriority(), * the task might be in the middle of scheduling on another CPU. */ rq = task_rq_lock(p, &flags); /* * The RT priorities are set via sched_setscheduler(), but we still * allow the 'normal' nice value to be set - but as expected * it wont have any effect on scheduling until the task is * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR: */ if (task_has_dl_policy(p) || task_has_rt_policy(p)) { p->static_prio = NICE_TO_PRIO(nice); goto out_unlock; } queued = task_on_rq_queued(p); if (queued) dequeue_task(rq, p, 0); p->static_prio = NICE_TO_PRIO(nice); set_load_weight(p); old_prio = p->prio; p->prio = effective_prio(p); delta = p->prio - old_prio; if (queued) { enqueue_task(rq, p, 0); /* * If the task increased its priority or is running and * lowered its priority, then reschedule its CPU: */ if (delta < 0 || (delta > 0 && task_running(rq, p))) resched_curr(rq); } out_unlock: task_rq_unlock(rq, p, &flags); } EXPORT_SYMBOL(set_user_nice); /* * can_nice - check if a task can reduce its nice value * @p: task * @nice: nice value */ int can_nice(const struct task_struct *p, const int nice) { /* convert nice value [19,-20] to rlimit style value [1,40] */ int nice_rlim = nice_to_rlimit(nice); return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || capable(CAP_SYS_NICE)); } #ifdef __ARCH_WANT_SYS_NICE /* * sys_nice - change the priority of the current process. * @increment: priority increment * * sys_setpriority is a more generic, but much slower function that * does similar things. */ SYSCALL_DEFINE1(nice, int, increment) { long nice, retval; /* * Setpriority might change our priority at the same moment. * We don't have to worry. Conceptually one call occurs first * and we have a single winner. */ increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH); nice = task_nice(current) + increment; nice = clamp_val(nice, MIN_NICE, MAX_NICE); if (increment < 0 && !can_nice(current, nice)) return -EPERM; retval = security_task_setnice(current, nice); if (retval) return retval; set_user_nice(current, nice); return 0; } #endif /** * task_prio - return the priority value of a given task. * @p: the task in question. * * Return: The priority value as seen by users in /proc. * RT tasks are offset by -200. Normal tasks are centered * around 0, value goes from -16 to +15. */ int task_prio(const struct task_struct *p) { return p->prio - MAX_RT_PRIO; } /** * idle_cpu - is a given cpu idle currently? * @cpu: the processor in question. * * Return: 1 if the CPU is currently idle. 0 otherwise. */ int idle_cpu(int cpu) { 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; } /** * idle_task - return the idle task for a given cpu. * @cpu: the processor in question. * * Return: The idle task for the cpu @cpu. */ struct task_struct *idle_task(int cpu) { return cpu_rq(cpu)->idle; } /** * find_process_by_pid - find a process with a matching PID value. * @pid: the pid in question. * * The task of @pid, if found. %NULL otherwise. */ static struct task_struct *find_process_by_pid(pid_t pid) { return pid ? find_task_by_vpid(pid) : current; } /* * This function initializes the sched_dl_entity of a newly becoming * SCHED_DEADLINE task. * * Only the static values are considered here, the actual runtime and the * absolute deadline will be properly calculated when the task is enqueued * for the first time with its new policy. */ static void __setparam_dl(struct task_struct *p, const struct sched_attr *attr) { struct sched_dl_entity *dl_se = &p->dl; dl_se->dl_runtime = attr->sched_runtime; dl_se->dl_deadline = attr->sched_deadline; dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; dl_se->flags = attr->sched_flags; dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime); /* * Changing the parameters of a task is 'tricky' and we're not doing * the correct thing -- also see task_dead_dl() and switched_from_dl(). * * What we SHOULD do is delay the bandwidth release until the 0-lag * point. This would include retaining the task_struct until that time * and change dl_overflow() to not immediately decrement the current * amount. * * Instead we retain the current runtime/deadline and let the new * parameters take effect after the current reservation period lapses. * This is safe (albeit pessimistic) because the 0-lag point is always * before the current scheduling deadline. * * We can still have temporary overloads because we do not delay the * change in bandwidth until that time; so admission control is * not on the safe side. It does however guarantee tasks will never * consume more than promised. */ } /* * sched_setparam() passes in -1 for its policy, to let the functions * it calls know not to change it. */ #define SETPARAM_POLICY -1 static void __setscheduler_params(struct task_struct *p, const struct sched_attr *attr) { int policy = attr->sched_policy; if (policy == SETPARAM_POLICY) policy = p->policy; p->policy = policy; if (dl_policy(policy)) __setparam_dl(p, attr); else if (fair_policy(policy)) p->static_prio = NICE_TO_PRIO(attr->sched_nice); /* * __sched_setscheduler() ensures attr->sched_priority == 0 when * !rt_policy. Always setting this ensures that things like * getparam()/getattr() don't report silly values for !rt tasks. */ p->rt_priority = attr->sched_priority; p->normal_prio = normal_prio(p); set_load_weight(p); } /* Actually do priority change: must hold pi & rq lock. */ static void __setscheduler(struct rq *rq, struct task_struct *p, const struct sched_attr *attr, bool keep_boost) { __setscheduler_params(p, attr); /* * Keep a potential priority boosting if called from * sched_setscheduler(). */ if (keep_boost) p->prio = rt_mutex_get_effective_prio(p, normal_prio(p)); else p->prio = normal_prio(p); if (dl_prio(p->prio)) p->sched_class = &dl_sched_class; else if (rt_prio(p->prio)) p->sched_class = &rt_sched_class; else p->sched_class = &fair_sched_class; } static void __getparam_dl(struct task_struct *p, struct sched_attr *attr) { struct sched_dl_entity *dl_se = &p->dl; attr->sched_priority = p->rt_priority; attr->sched_runtime = dl_se->dl_runtime; attr->sched_deadline = dl_se->dl_deadline; attr->sched_period = dl_se->dl_period; attr->sched_flags = dl_se->flags; } /* * This function validates the new parameters of a -deadline task. * We ask for the deadline not being zero, and greater or equal * than the runtime, as well as the period of being zero or * greater than deadline. Furthermore, we have to be sure that * user parameters are above the internal resolution of 1us (we * check sched_runtime only since it is always the smaller one) and * below 2^63 ns (we have to check both sched_deadline and * sched_period, as the latter can be zero). */ static bool __checkparam_dl(const struct sched_attr *attr) { /* deadline != 0 */ if (attr->sched_deadline == 0) return false; /* * Since we truncate DL_SCALE bits, make sure we're at least * that big. */ if (attr->sched_runtime < (1ULL << DL_SCALE)) return false; /* * Since we use the MSB for wrap-around and sign issues, make * sure it's not set (mind that period can be equal to zero). */ if (attr->sched_deadline & (1ULL << 63) || attr->sched_period & (1ULL << 63)) return false; /* runtime <= deadline <= period (if period != 0) */ if ((attr->sched_period != 0 && attr->sched_period < attr->sched_deadline) || attr->sched_deadline < attr->sched_runtime) return false; return true; } /* * check the target process has a UID that matches the current process's */ static bool check_same_owner(struct task_struct *p) { const struct cred *cred = current_cred(), *pcred; bool match; rcu_read_lock(); pcred = __task_cred(p); match = (uid_eq(cred->euid, pcred->euid) || uid_eq(cred->euid, pcred->uid)); rcu_read_unlock(); return match; } static bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr) { struct sched_dl_entity *dl_se = &p->dl; if (dl_se->dl_runtime != attr->sched_runtime || dl_se->dl_deadline != attr->sched_deadline || dl_se->dl_period != attr->sched_period || dl_se->flags != attr->sched_flags) return true; return false; } static int __sched_setscheduler(struct task_struct *p, const struct sched_attr *attr, bool user) { int newprio = dl_policy(attr->sched_policy) ? MAX_DL_PRIO - 1 : MAX_RT_PRIO - 1 - attr->sched_priority; int retval, oldprio, oldpolicy = -1, queued, running; int new_effective_prio, policy = attr->sched_policy; unsigned long flags; const struct sched_class *prev_class; struct rq *rq; int reset_on_fork; /* may grab non-irq protected spin_locks */ BUG_ON(in_interrupt()); recheck: /* double check policy once rq lock held */ if (policy < 0) { reset_on_fork = p->sched_reset_on_fork; policy = oldpolicy = p->policy; } else { reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK); if (policy != SCHED_DEADLINE && policy != SCHED_FIFO && policy != SCHED_RR && policy != SCHED_NORMAL && policy != SCHED_BATCH && policy != SCHED_IDLE) return -EINVAL; } if (attr->sched_flags & ~(SCHED_FLAG_RESET_ON_FORK)) return -EINVAL; /* * Valid priorities for SCHED_FIFO and SCHED_RR are * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, * SCHED_BATCH and SCHED_IDLE is 0. */ if ((p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) || (!p->mm && attr->sched_priority > MAX_RT_PRIO-1)) return -EINVAL; if ((dl_policy(policy) && !__checkparam_dl(attr)) || (rt_policy(policy) != (attr->sched_priority != 0))) return -EINVAL; /* * Allow unprivileged RT tasks to decrease priority: */ if (user && !capable(CAP_SYS_NICE)) { if (fair_policy(policy)) { if (attr->sched_nice < task_nice(p) && !can_nice(p, attr->sched_nice)) return -EPERM; } if (rt_policy(policy)) { unsigned long rlim_rtprio = task_rlimit(p, RLIMIT_RTPRIO); /* can't set/change the rt policy */ if (policy != p->policy && !rlim_rtprio) return -EPERM; /* can't increase priority */ if (attr->sched_priority > p->rt_priority && attr->sched_priority > rlim_rtprio) return -EPERM; } /* * Can't set/change SCHED_DEADLINE policy at all for now * (safest behavior); in the future we would like to allow * unprivileged DL tasks to increase their relative deadline * or reduce their runtime (both ways reducing utilization) */ if (dl_policy(policy)) return -EPERM; /* * Treat SCHED_IDLE as nice 20. Only allow a switch to * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. */ if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) { if (!can_nice(p, task_nice(p))) return -EPERM; } /* can't change other user's priorities */ if (!check_same_owner(p)) return -EPERM; /* Normal users shall not reset the sched_reset_on_fork flag */ if (p->sched_reset_on_fork && !reset_on_fork) return -EPERM; } if (user) { retval = security_task_setscheduler(p); if (retval) return retval; } /* * make sure no PI-waiters arrive (or leave) while we are * changing the priority of the task: * * To be able to change p->policy safely, the appropriate * runqueue lock must be held. */ rq = task_rq_lock(p, &flags); /* * Changing the policy of the stop threads its a very bad idea */ if (p == rq->stop) { task_rq_unlock(rq, p, &flags); return -EINVAL; } /* * If not changing anything there's no need to proceed further, * but store a possible modification of reset_on_fork. */ if (unlikely(policy == p->policy)) { if (fair_policy(policy) && attr->sched_nice != task_nice(p)) goto change; if (rt_policy(policy) && attr->sched_priority != p->rt_priority) goto change; if (dl_policy(policy) && dl_param_changed(p, attr)) goto change; p->sched_reset_on_fork = reset_on_fork; task_rq_unlock(rq, p, &flags); return 0; } change: if (user) { #ifdef CONFIG_RT_GROUP_SCHED /* * Do not allow realtime tasks into groups that have no runtime * assigned. */ if (rt_bandwidth_enabled() && rt_policy(policy) && task_group(p)->rt_bandwidth.rt_runtime == 0 && !task_group_is_autogroup(task_group(p))) { task_rq_unlock(rq, p, &flags); return -EPERM; } #endif #ifdef CONFIG_SMP if (dl_bandwidth_enabled() && dl_policy(policy)) { cpumask_t *span = rq->rd->span; /* * Don't allow tasks with an affinity mask smaller than * the entire root_domain to become SCHED_DEADLINE. We * will also fail if there's no bandwidth available. */ if (!cpumask_subset(span, &p->cpus_allowed) || rq->rd->dl_bw.bw == 0) { task_rq_unlock(rq, p, &flags); return -EPERM; } } #endif } /* recheck policy now with rq lock held */ if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { policy = oldpolicy = -1; task_rq_unlock(rq, p, &flags); goto recheck; } /* * If setscheduling to SCHED_DEADLINE (or changing the parameters * of a SCHED_DEADLINE task) we need to check if enough bandwidth * is available. */ if ((dl_policy(policy) || dl_task(p)) && dl_overflow(p, policy, attr)) { task_rq_unlock(rq, p, &flags); return -EBUSY; } p->sched_reset_on_fork = reset_on_fork; oldprio = p->prio; /* * Take priority boosted tasks into account. If the new * effective priority is unchanged, we just store the new * normal parameters and do not touch the scheduler class and * the runqueue. This will be done when the task deboost * itself. */ new_effective_prio = rt_mutex_get_effective_prio(p, newprio); if (new_effective_prio == oldprio) { __setscheduler_params(p, attr); task_rq_unlock(rq, p, &flags); return 0; } queued = task_on_rq_queued(p); running = task_current(rq, p); if (queued) dequeue_task(rq, p, 0); if (running) put_prev_task(rq, p); prev_class = p->sched_class; __setscheduler(rq, p, attr, true); if (running) p->sched_class->set_curr_task(rq); if (queued) { /* * We enqueue to tail when the priority of a task is * increased (user space view). */ enqueue_task(rq, p, oldprio <= p->prio ? ENQUEUE_HEAD : 0); } check_class_changed(rq, p, prev_class, oldprio); task_rq_unlock(rq, p, &flags); rt_mutex_adjust_pi(p); return 0; } static int _sched_setscheduler(struct task_struct *p, int policy, const struct sched_param *param, bool check) { struct sched_attr attr = { .sched_policy = policy, .sched_priority = param->sched_priority, .sched_nice = PRIO_TO_NICE(p->static_prio), }; /* Fixup the legacy SCHED_RESET_ON_FORK hack. */ if ((policy != SETPARAM_POLICY) && (policy & SCHED_RESET_ON_FORK)) { attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; policy &= ~SCHED_RESET_ON_FORK; attr.sched_policy = policy; } return __sched_setscheduler(p, &attr, check); } /** * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. * @p: the task in question. * @policy: new policy. * @param: structure containing the new RT priority. * * Return: 0 on success. An error code otherwise. * * NOTE that the task may be already dead. */ int sched_setscheduler(struct task_struct *p, int policy, const struct sched_param *param) { return _sched_setscheduler(p, policy, param, true); } EXPORT_SYMBOL_GPL(sched_setscheduler); int sched_setattr(struct task_struct *p, const struct sched_attr *attr) { return __sched_setscheduler(p, attr, true); } EXPORT_SYMBOL_GPL(sched_setattr); /** * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. * @p: the task in question. * @policy: new policy. * @param: structure containing the new RT priority. * * Just like sched_setscheduler, only don't bother checking if the * current context has permission. For example, this is needed in * stop_machine(): we create temporary high priority worker threads, * but our caller might not have that capability. * * Return: 0 on success. An error code otherwise. */ int sched_setscheduler_nocheck(struct task_struct *p, int policy, const struct sched_param *param) { return _sched_setscheduler(p, policy, param, false); } static int do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) { struct sched_param lparam; struct task_struct *p; int retval; if (!param || pid < 0) return -EINVAL; if (copy_from_user(&lparam, param, sizeof(struct sched_param))) return -EFAULT; rcu_read_lock(); retval = -ESRCH; p = find_process_by_pid(pid); if (p != NULL) retval = sched_setscheduler(p, policy, &lparam); rcu_read_unlock(); return retval; } /* * Mimics kernel/events/core.c perf_copy_attr(). */ static int sched_copy_attr(struct sched_attr __user *uattr, struct sched_attr *attr) { u32 size; int ret; if (!access_ok(VERIFY_WRITE, uattr, SCHED_ATTR_SIZE_VER0)) return -EFAULT; /* * zero the full structure, so that a short copy will be nice. */ memset(attr, 0, sizeof(*attr)); ret = get_user(size, &uattr->size); if (ret) return ret; if (size > PAGE_SIZE) /* silly large */ goto err_size; if (!size) /* abi compat */ size = SCHED_ATTR_SIZE_VER0; if (size < SCHED_ATTR_SIZE_VER0) goto err_size; /* * If we're handed a bigger struct than we know of, * ensure all the unknown bits are 0 - i.e. new * user-space does not rely on any kernel feature * extensions we dont know about yet. */ if (size > sizeof(*attr)) { unsigned char __user *addr; unsigned char __user *end; unsigned char val; addr = (void __user *)uattr + sizeof(*attr); end = (void __user *)uattr + size; for (; addr < end; addr++) { ret = get_user(val, addr); if (ret) return ret; if (val) goto err_size; } size = sizeof(*attr); } ret = copy_from_user(attr, uattr, size); if (ret) return -EFAULT; /* * XXX: do we want to be lenient like existing syscalls; or do we want * to be strict and return an error on out-of-bounds values? */ attr->sched_nice = clamp(attr->sched_nice, MIN_NICE, MAX_NICE); return 0; err_size: put_user(sizeof(*attr), &uattr->size); return -E2BIG; } /** * sys_sched_setscheduler - set/change the scheduler policy and RT priority * @pid: the pid in question. * @policy: new policy. * @param: structure containing the new RT priority. * * Return: 0 on success. An error code otherwise. */ SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, struct sched_param __user *, param) { /* negative values for policy are not valid */ if (policy < 0) return -EINVAL; return do_sched_setscheduler(pid, policy, param); } /** * sys_sched_setparam - set/change the RT priority of a thread * @pid: the pid in question. * @param: structure containing the new RT priority. * * Return: 0 on success. An error code otherwise. */ SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) { return do_sched_setscheduler(pid, SETPARAM_POLICY, param); } /** * sys_sched_setattr - same as above, but with extended sched_attr * @pid: the pid in question. * @uattr: structure containing the extended parameters. * @flags: for future extension. */ SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr, unsigned int, flags) { struct sched_attr attr; struct task_struct *p; int retval; if (!uattr || pid < 0 || flags) return -EINVAL; retval = sched_copy_attr(uattr, &attr); if (retval) return retval; if ((int)attr.sched_policy < 0) return -EINVAL; rcu_read_lock(); retval = -ESRCH; p = find_process_by_pid(pid); if (p != NULL) retval = sched_setattr(p, &attr); rcu_read_unlock(); return retval; } /** * sys_sched_getscheduler - get the policy (scheduling class) of a thread * @pid: the pid in question. * * Return: On success, the policy of the thread. Otherwise, a negative error * code. */ SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) { struct task_struct *p; int retval; if (pid < 0) return -EINVAL; retval = -ESRCH; rcu_read_lock(); p = find_process_by_pid(pid); if (p) { retval = security_task_getscheduler(p); if (!retval) retval = p->policy | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); } rcu_read_unlock(); return retval; } /** * sys_sched_getparam - get the RT priority of a thread * @pid: the pid in question. * @param: structure containing the RT priority. * * Return: On success, 0 and the RT priority is in @param. Otherwise, an error * code. */ SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) { struct sched_param lp = { .sched_priority = 0 }; struct task_struct *p; int retval; if (!param || pid < 0) return -EINVAL; rcu_read_lock(); p = find_process_by_pid(pid); retval = -ESRCH; if (!p) goto out_unlock; retval = security_task_getscheduler(p); if (retval) goto out_unlock; if (task_has_rt_policy(p)) lp.sched_priority = p->rt_priority; rcu_read_unlock(); /* * This one might sleep, we cannot do it with a spinlock held ... */ retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; return retval; out_unlock: rcu_read_unlock(); return retval; } static int sched_read_attr(struct sched_attr __user *uattr, struct sched_attr *attr, unsigned int usize) { int ret; if (!access_ok(VERIFY_WRITE, uattr, usize)) return -EFAULT; /* * If we're handed a smaller struct than we know of, * ensure all the unknown bits are 0 - i.e. old * user-space does not get uncomplete information. */ if (usize < sizeof(*attr)) { unsigned char *addr; unsigned char *end; addr = (void *)attr + usize; end = (void *)attr + sizeof(*attr); for (; addr < end; addr++) { if (*addr) return -EFBIG; } attr->size = usize; } ret = copy_to_user(uattr, attr, attr->size); if (ret) return -EFAULT; return 0; } /** * sys_sched_getattr - similar to sched_getparam, but with sched_attr * @pid: the pid in question. * @uattr: structure containing the extended parameters. * @size: sizeof(attr) for fwd/bwd comp. * @flags: for future extension. */ SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, unsigned int, size, unsigned int, flags) { struct sched_attr attr = { .size = sizeof(struct sched_attr), }; struct task_struct *p; int retval; if (!uattr || pid < 0 || size > PAGE_SIZE || size < SCHED_ATTR_SIZE_VER0 || flags) return -EINVAL; rcu_read_lock(); p = find_process_by_pid(pid); retval = -ESRCH; if (!p) goto out_unlock; retval = security_task_getscheduler(p); if (retval) goto out_unlock; attr.sched_policy = p->policy; if (p->sched_reset_on_fork) attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; if (task_has_dl_policy(p)) __getparam_dl(p, &attr); else if (task_has_rt_policy(p)) attr.sched_priority = p->rt_priority; else attr.sched_nice = task_nice(p); rcu_read_unlock(); retval = sched_read_attr(uattr, &attr, size); return retval; out_unlock: rcu_read_unlock(); return retval; } long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) { cpumask_var_t cpus_allowed, new_mask; struct task_struct *p; int retval; rcu_read_lock(); p = find_process_by_pid(pid); if (!p) { rcu_read_unlock(); return -ESRCH; } /* Prevent p going away */ get_task_struct(p); rcu_read_unlock(); if (p->flags & PF_NO_SETAFFINITY) { retval = -EINVAL; goto out_put_task; } if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { retval = -ENOMEM; goto out_put_task; } if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { retval = -ENOMEM; goto out_free_cpus_allowed; } retval = -EPERM; if (!check_same_owner(p)) { rcu_read_lock(); if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { rcu_read_unlock(); goto out_free_new_mask; } rcu_read_unlock(); } retval = security_task_setscheduler(p); if (retval) goto out_free_new_mask; cpuset_cpus_allowed(p, cpus_allowed); cpumask_and(new_mask, in_mask, cpus_allowed); /* * Since bandwidth control happens on root_domain basis, * if admission test is enabled, we only admit -deadline * tasks allowed to run on all the CPUs in the task's * root_domain. */ #ifdef CONFIG_SMP if (task_has_dl_policy(p) && dl_bandwidth_enabled()) { rcu_read_lock(); if (!cpumask_subset(task_rq(p)->rd->span, new_mask)) { retval = -EBUSY; rcu_read_unlock(); goto out_free_new_mask; } rcu_read_unlock(); } #endif again: retval = set_cpus_allowed_ptr(p, new_mask); if (!retval) { cpuset_cpus_allowed(p, cpus_allowed); if (!cpumask_subset(new_mask, cpus_allowed)) { /* * We must have raced with a concurrent cpuset * update. Just reset the cpus_allowed to the * cpuset's cpus_allowed */ cpumask_copy(new_mask, cpus_allowed); goto again; } } out_free_new_mask: free_cpumask_var(new_mask); out_free_cpus_allowed: free_cpumask_var(cpus_allowed); out_put_task: put_task_struct(p); return retval; } static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, struct cpumask *new_mask) { if (len < cpumask_size()) cpumask_clear(new_mask); else if (len > cpumask_size()) len = cpumask_size(); return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; } /** * sys_sched_setaffinity - set the cpu affinity of a process * @pid: pid of the process * @len: length in bytes of the bitmask pointed to by user_mask_ptr * @user_mask_ptr: user-space pointer to the new cpu mask * * Return: 0 on success. An error code otherwise. */ SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, unsigned long __user *, user_mask_ptr) { cpumask_var_t new_mask; int retval; if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) return -ENOMEM; retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); if (retval == 0) retval = sched_setaffinity(pid, new_mask); free_cpumask_var(new_mask); return retval; } long sched_getaffinity(pid_t pid, struct cpumask *mask) { struct task_struct *p; unsigned long flags; int retval; rcu_read_lock(); retval = -ESRCH; p = find_process_by_pid(pid); if (!p) goto out_unlock; retval = security_task_getscheduler(p); if (retval) goto out_unlock; raw_spin_lock_irqsave(&p->pi_lock, flags); cpumask_and(mask, &p->cpus_allowed, cpu_active_mask); raw_spin_unlock_irqrestore(&p->pi_lock, flags); out_unlock: rcu_read_unlock(); return retval; } /** * sys_sched_getaffinity - get the cpu affinity of a process * @pid: pid of the process * @len: length in bytes of the bitmask pointed to by user_mask_ptr * @user_mask_ptr: user-space pointer to hold the current cpu mask * * Return: 0 on success. An error code otherwise. */ SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, unsigned long __user *, user_mask_ptr) { int ret; cpumask_var_t mask; if ((len * BITS_PER_BYTE) < nr_cpu_ids) return -EINVAL; if (len & (sizeof(unsigned long)-1)) return -EINVAL; if (!alloc_cpumask_var(&mask, GFP_KERNEL)) return -ENOMEM; ret = sched_getaffinity(pid, mask); if (ret == 0) { size_t retlen = min_t(size_t, len, cpumask_size()); if (copy_to_user(user_mask_ptr, mask, retlen)) ret = -EFAULT; else ret = retlen; } free_cpumask_var(mask); return ret; } /** * sys_sched_yield - yield the current processor to other threads. * * This function yields the current CPU to other tasks. If there are no * other threads running on this CPU then this function will return. * * Return: 0. */ SYSCALL_DEFINE0(sched_yield) { struct rq *rq = this_rq_lock(); schedstat_inc(rq, yld_count); current->sched_class->yield_task(rq); /* * Since we are going to call schedule() anyway, there's * no need to preempt or enable interrupts: */ __release(rq->lock); spin_release(&rq->lock.dep_map, 1, _THIS_IP_); do_raw_spin_unlock(&rq->lock); sched_preempt_enable_no_resched(); schedule(); return 0; } int __sched _cond_resched(void) { if (should_resched(0)) { preempt_schedule_common(); return 1; } return 0; } EXPORT_SYMBOL(_cond_resched); /* * __cond_resched_lock() - if a reschedule is pending, drop the given lock, * call schedule, and on return reacquire the lock. * * This works OK both with and without CONFIG_PREEMPT. We do strange low-level * operations here to prevent schedule() from being called twice (once via * spin_unlock(), once by hand). */ int __cond_resched_lock(spinlock_t *lock) { int resched = should_resched(PREEMPT_LOCK_OFFSET); int ret = 0; lockdep_assert_held(lock); if (spin_needbreak(lock) || resched) { spin_unlock(lock); if (resched) preempt_schedule_common(); else cpu_relax(); ret = 1; spin_lock(lock); } return ret; } EXPORT_SYMBOL(__cond_resched_lock); int __sched __cond_resched_softirq(void) { BUG_ON(!in_softirq()); if (should_resched(SOFTIRQ_DISABLE_OFFSET)) { local_bh_enable(); preempt_schedule_common(); local_bh_disable(); return 1; } return 0; } EXPORT_SYMBOL(__cond_resched_softirq); /** * yield - yield the current processor to other threads. * * Do not ever use this function, there's a 99% chance you're doing it wrong. * * The scheduler is at all times free to pick the calling task as the most * eligible task to run, if removing the yield() call from your code breaks * it, its already broken. * * Typical broken usage is: * * while (!event) * yield(); * * where one assumes that yield() will let 'the other' process run that will * make event true. If the current task is a SCHED_FIFO task that will never * happen. Never use yield() as a progress guarantee!! * * If you want to use yield() to wait for something, use wait_event(). * If you want to use yield() to be 'nice' for others, use cond_resched(). * If you still want to use yield(), do not! */ void __sched yield(void) { set_current_state(TASK_RUNNING); sys_sched_yield(); } EXPORT_SYMBOL(yield); /** * yield_to - yield the current processor to another thread in * your thread group, or accelerate that thread toward the * processor it's on. * @p: target task * @preempt: whether task preemption is allowed or not * * It's the caller's job to ensure that the target task struct * can't go away on us before we can do any checks. * * Return: * true (>0) if we indeed boosted the target task. * false (0) if we failed to boost the target. * -ESRCH if there's no task to yield to. */ int __sched yield_to(struct task_struct *p, bool preempt) { struct task_struct *curr = current; struct rq *rq, *p_rq; unsigned long flags; int yielded = 0; local_irq_save(flags); rq = this_rq(); again: p_rq = task_rq(p); /* * If we're the only runnable task on the rq and target rq also * has only one task, there's absolutely no point in yielding. */ if (rq->nr_running == 1 && p_rq->nr_running == 1) { yielded = -ESRCH; goto out_irq; } double_rq_lock(rq, p_rq); if (task_rq(p) != p_rq) { double_rq_unlock(rq, p_rq); goto again; } if (!curr->sched_class->yield_to_task) goto out_unlock; if (curr->sched_class != p->sched_class) goto out_unlock; if (task_running(p_rq, p) || p->state) goto out_unlock; yielded = curr->sched_class->yield_to_task(rq, p, preempt); if (yielded) { schedstat_inc(rq, yld_count); /* * Make p's CPU reschedule; pick_next_entity takes care of * fairness. */ if (preempt && rq != p_rq) resched_curr(p_rq); } out_unlock: double_rq_unlock(rq, p_rq); out_irq: local_irq_restore(flags); if (yielded > 0) schedule(); return yielded; } EXPORT_SYMBOL_GPL(yield_to); /* * This task is about to go to sleep on IO. Increment rq->nr_iowait so * that process accounting knows that this is a task in IO wait state. */ long __sched io_schedule_timeout(long timeout) { int old_iowait = current->in_iowait; struct rq *rq; long ret; current->in_iowait = 1; blk_schedule_flush_plug(current); delayacct_blkio_start(); rq = raw_rq(); atomic_inc(&rq->nr_iowait); ret = schedule_timeout(timeout); current->in_iowait = old_iowait; atomic_dec(&rq->nr_iowait); delayacct_blkio_end(); return ret; } EXPORT_SYMBOL(io_schedule_timeout); /** * sys_sched_get_priority_max - return maximum RT priority. * @policy: scheduling class. * * Return: On success, this syscall returns the maximum * rt_priority that can be used by a given scheduling class. * On failure, a negative error code is returned. */ SYSCALL_DEFINE1(sched_get_priority_max, int, policy) { int ret = -EINVAL; switch (policy) { case SCHED_FIFO: case SCHED_RR: ret = MAX_USER_RT_PRIO-1; break; case SCHED_DEADLINE: case SCHED_NORMAL: case SCHED_BATCH: case SCHED_IDLE: ret = 0; break; } return ret; } /** * sys_sched_get_priority_min - return minimum RT priority. * @policy: scheduling class. * * Return: On success, this syscall returns the minimum * rt_priority that can be used by a given scheduling class. * On failure, a negative error code is returned. */ SYSCALL_DEFINE1(sched_get_priority_min, int, policy) { int ret = -EINVAL; switch (policy) { case SCHED_FIFO: case SCHED_RR: ret = 1; break; case SCHED_DEADLINE: case SCHED_NORMAL: case SCHED_BATCH: case SCHED_IDLE: ret = 0; } return ret; } /** * sys_sched_rr_get_interval - return the default timeslice of a process. * @pid: pid of the process. * @interval: userspace pointer to the timeslice value. * * this syscall writes the default timeslice value of a given process * into the user-space timespec buffer. A value of '0' means infinity. * * Return: On success, 0 and the timeslice is in @interval. Otherwise, * an error code. */ SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, struct timespec __user *, interval) { struct task_struct *p; unsigned int time_slice; unsigned long flags; struct rq *rq; int retval; struct timespec t; if (pid < 0) return -EINVAL; retval = -ESRCH; rcu_read_lock(); p = find_process_by_pid(pid); if (!p) goto out_unlock; retval = security_task_getscheduler(p); if (retval) goto out_unlock; rq = task_rq_lock(p, &flags); time_slice = 0; if (p->sched_class->get_rr_interval) time_slice = p->sched_class->get_rr_interval(rq, p); task_rq_unlock(rq, p, &flags); rcu_read_unlock(); jiffies_to_timespec(time_slice, &t); retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; return retval; out_unlock: rcu_read_unlock(); return retval; } static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; void sched_show_task(struct task_struct *p) { unsigned long free = 0; int ppid; unsigned long state = p->state; if (state) state = __ffs(state) + 1; printk(KERN_INFO "%-15.15s %c", p->comm, state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); #if BITS_PER_LONG == 32 if (state == TASK_RUNNING) printk(KERN_CONT " running "); else printk(KERN_CONT " %08lx ", thread_saved_pc(p)); #else if (state == TASK_RUNNING) printk(KERN_CONT " running task "); else printk(KERN_CONT " %016lx ", thread_saved_pc(p)); #endif #ifdef CONFIG_DEBUG_STACK_USAGE free = stack_not_used(p); #endif ppid = 0; rcu_read_lock(); if (pid_alive(p)) ppid = task_pid_nr(rcu_dereference(p->real_parent)); rcu_read_unlock(); printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, task_pid_nr(p), ppid, (unsigned long)task_thread_info(p)->flags); print_worker_info(KERN_INFO, p); show_stack(p, NULL); } void show_state_filter(unsigned long state_filter) { struct task_struct *g, *p; #if BITS_PER_LONG == 32 printk(KERN_INFO " task PC stack pid father\n"); #else printk(KERN_INFO " task PC stack pid father\n"); #endif rcu_read_lock(); for_each_process_thread(g, p) { /* * reset the NMI-timeout, listing all files on a slow * console might take a lot of time: * Also, reset softlockup watchdogs on all CPUs, because * another CPU might be blocked waiting for us to process * an IPI. */ touch_nmi_watchdog(); touch_all_softlockup_watchdogs(); if (!state_filter || (p->state & state_filter)) sched_show_task(p); } #ifdef CONFIG_SCHED_DEBUG sysrq_sched_debug_show(); #endif rcu_read_unlock(); /* * Only show locks if all tasks are dumped: */ if (!state_filter) debug_show_all_locks(); } void init_idle_bootup_task(struct task_struct *idle) { idle->sched_class = &idle_sched_class; } /** * init_idle - set up an idle thread for a given CPU * @idle: task in question * @cpu: cpu the idle task belongs to * * NOTE: this function does not set the idle thread's NEED_RESCHED * flag, to make booting more robust. */ void init_idle(struct task_struct *idle, int cpu) { struct rq *rq = cpu_rq(cpu); unsigned long flags; raw_spin_lock_irqsave(&rq->lock, flags); __sched_fork(0, idle); idle->state = TASK_RUNNING; idle->se.exec_start = sched_clock(); do_set_cpus_allowed(idle, cpumask_of(cpu)); /* * We're having a chicken and egg problem, even though we are * holding rq->lock, the cpu isn't yet set to this cpu so the * lockdep check in task_group() will fail. * * Similar case to sched_fork(). / Alternatively we could * use task_rq_lock() here and obtain the other rq->lock. * * Silence PROVE_RCU */ rcu_read_lock(); __set_task_cpu(idle, cpu); rcu_read_unlock(); rq->curr = rq->idle = idle; idle->on_rq = TASK_ON_RQ_QUEUED; #if defined(CONFIG_SMP) idle->on_cpu = 1; #endif raw_spin_unlock_irqrestore(&rq->lock, flags); /* Set the preempt count _outside_ the spinlocks! */ init_idle_preempt_count(idle, cpu); /* * The idle tasks have their own, simple scheduling class: */ idle->sched_class = &idle_sched_class; ftrace_graph_init_idle_task(idle, cpu); vtime_init_idle(idle, cpu); #if defined(CONFIG_SMP) sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); #endif } int cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial) { int ret = 1, trial_cpus; struct dl_bw *cur_dl_b; unsigned long flags; if (!cpumask_weight(cur)) return ret; rcu_read_lock_sched(); cur_dl_b = dl_bw_of(cpumask_any(cur)); trial_cpus = cpumask_weight(trial); raw_spin_lock_irqsave(&cur_dl_b->lock, flags); if (cur_dl_b->bw != -1 && cur_dl_b->bw * trial_cpus < cur_dl_b->total_bw) ret = 0; raw_spin_unlock_irqrestore(&cur_dl_b->lock, flags); rcu_read_unlock_sched(); return ret; } int task_can_attach(struct task_struct *p, const struct cpumask *cs_cpus_allowed) { int ret = 0; /* * Kthreads which disallow setaffinity shouldn't be moved * to a new cpuset; we don't want to change their cpu * affinity and isolating such threads by their set of * allowed nodes is unnecessary. Thus, cpusets are not * applicable for such threads. This prevents checking for * success of set_cpus_allowed_ptr() on all attached tasks * before cpus_allowed may be changed. */ if (p->flags & PF_NO_SETAFFINITY) { ret = -EINVAL; goto out; } #ifdef CONFIG_SMP if (dl_task(p) && !cpumask_intersects(task_rq(p)->rd->span, cs_cpus_allowed)) { unsigned int dest_cpu = cpumask_any_and(cpu_active_mask, cs_cpus_allowed); struct dl_bw *dl_b; bool overflow; int cpus; unsigned long flags; rcu_read_lock_sched(); dl_b = dl_bw_of(dest_cpu); raw_spin_lock_irqsave(&dl_b->lock, flags); cpus = dl_bw_cpus(dest_cpu); overflow = __dl_overflow(dl_b, cpus, 0, p->dl.dl_bw); if (overflow) ret = -EBUSY; else { /* * We reserve space for this task in the destination * root_domain, as we can't fail after this point. * We will free resources in the source root_domain * later on (see set_cpus_allowed_dl()). */ __dl_add(dl_b, p->dl.dl_bw); } raw_spin_unlock_irqrestore(&dl_b->lock, flags); rcu_read_unlock_sched(); } #endif out: return ret; } #ifdef CONFIG_SMP /* * move_queued_task - move a queued task to new rq. * * Returns (locked) new rq. Old rq's lock is released. */ static struct rq *move_queued_task(struct task_struct *p, int new_cpu) { struct rq *rq = task_rq(p); lockdep_assert_held(&rq->lock); dequeue_task(rq, p, 0); p->on_rq = TASK_ON_RQ_MIGRATING; set_task_cpu(p, new_cpu); raw_spin_unlock(&rq->lock); rq = cpu_rq(new_cpu); raw_spin_lock(&rq->lock); BUG_ON(task_cpu(p) != new_cpu); p->on_rq = TASK_ON_RQ_QUEUED; enqueue_task(rq, p, 0); check_preempt_curr(rq, p, 0); return rq; } void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) { if (p->sched_class->set_cpus_allowed) p->sched_class->set_cpus_allowed(p, new_mask); cpumask_copy(&p->cpus_allowed, new_mask); p->nr_cpus_allowed = cpumask_weight(new_mask); } /* * This is how migration works: * * 1) we invoke migration_cpu_stop() on the target CPU using * stop_one_cpu(). * 2) stopper starts to run (implicitly forcing the migrated thread * off the CPU) * 3) it checks whether the migrated task is still in the wrong runqueue. * 4) if it's in the wrong runqueue then the migration thread removes * it and puts it into the right queue. * 5) stopper completes and stop_one_cpu() returns and the migration * is done. */ /* * Change a given task's CPU affinity. Migrate the thread to a * proper CPU and schedule it away if the CPU it's executing on * is removed from the allowed bitmask. * * NOTE: the caller must have a valid reference to the task, the * task must not exit() & deallocate itself prematurely. The * call is not atomic; no spinlocks may be held. */ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) { unsigned long flags; struct rq *rq; unsigned int dest_cpu; int ret = 0; rq = task_rq_lock(p, &flags); if (cpumask_equal(&p->cpus_allowed, new_mask)) goto out; if (!cpumask_intersects(new_mask, cpu_active_mask)) { ret = -EINVAL; goto out; } do_set_cpus_allowed(p, new_mask); #if defined(CONFIG_BCM_KF_CPU_AFFINITY_HINT) && \ defined(CONFIG_BCM_PROC_CPU_AFFINITY_HINT) cpumask_copy(&p->cpus_hint, new_mask); #endif /* Can the task run on the task's current CPU? If so, we're done */ if (cpumask_test_cpu(task_cpu(p), new_mask)) goto out; dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); if (task_running(rq, p) || p->state == TASK_WAKING) { struct migration_arg arg = { p, dest_cpu }; /* Need help from migration thread: drop lock and wait. */ task_rq_unlock(rq, p, &flags); stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); tlb_migrate_finish(p->mm); return 0; } else if (task_on_rq_queued(p)) rq = move_queued_task(p, dest_cpu); out: task_rq_unlock(rq, p, &flags); return ret; } EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); /* * Move (not current) task off this cpu, onto dest cpu. We're doing * this because either it can't run here any more (set_cpus_allowed() * away from this CPU, or CPU going down), or because we're * attempting to rebalance this task on exec (sched_exec). * * So we race with normal scheduler movements, but that's OK, as long * as the task is no longer on this CPU. * * Returns non-zero if task was successfully migrated. */ static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) { struct rq *rq; int ret = 0; if (unlikely(!cpu_active(dest_cpu))) return ret; rq = cpu_rq(src_cpu); raw_spin_lock(&p->pi_lock); raw_spin_lock(&rq->lock); /* Already moved. */ if (task_cpu(p) != src_cpu) goto done; /* Affinity changed (again). */ if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) goto fail; /* * If we're not on a rq, the next wake-up will ensure we're * placed properly. */ if (task_on_rq_queued(p)) rq = move_queued_task(p, dest_cpu); done: ret = 1; fail: raw_spin_unlock(&rq->lock); raw_spin_unlock(&p->pi_lock); return ret; } #ifdef CONFIG_NUMA_BALANCING /* Migrate current task p to target_cpu */ int migrate_task_to(struct task_struct *p, int target_cpu) { struct migration_arg arg = { p, target_cpu }; int curr_cpu = task_cpu(p); if (curr_cpu == target_cpu) return 0; if (!cpumask_test_cpu(target_cpu, tsk_cpus_allowed(p))) return -EINVAL; /* TODO: This is not properly updating schedstats */ trace_sched_move_numa(p, curr_cpu, target_cpu); return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg); } /* * Requeue a task on a given node and accurately track the number of NUMA * tasks on the runqueues */ void sched_setnuma(struct task_struct *p, int nid) { struct rq *rq; unsigned long flags; bool queued, running; rq = task_rq_lock(p, &flags); queued = task_on_rq_queued(p); running = task_current(rq, p); if (queued) dequeue_task(rq, p, 0); if (running) put_prev_task(rq, p); p->numa_preferred_nid = nid; if (running) p->sched_class->set_curr_task(rq); if (queued) enqueue_task(rq, p, 0); task_rq_unlock(rq, p, &flags); } #endif /* * migration_cpu_stop - this will be executed by a highprio stopper thread * and performs thread migration by bumping thread off CPU then * 'pushing' onto another runqueue. */ static int migration_cpu_stop(void *data) { struct migration_arg *arg = data; /* * The original target cpu might have gone down and we might * be on another cpu but it doesn't matter. */ local_irq_disable(); /* * We need to explicitly wake pending tasks before running * __migrate_task() such that we will not miss enforcing cpus_allowed * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test. */ sched_ttwu_pending(); __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu); local_irq_enable(); return 0; } #ifdef CONFIG_HOTPLUG_CPU /* * Ensures that the idle task is using init_mm right before its cpu goes * offline. */ void idle_task_exit(void) { struct mm_struct *mm = current->active_mm; BUG_ON(cpu_online(smp_processor_id())); if (mm != &init_mm) { switch_mm(mm, &init_mm, current); finish_arch_post_lock_switch(); } mmdrop(mm); } /* * Since this CPU is going 'away' for a while, fold any nr_active delta * we might have. Assumes we're called after migrate_tasks() so that the * nr_active count is stable. * * Also see the comment "Global load-average calculations". */ static void calc_load_migrate(struct rq *rq) { long delta = calc_load_fold_active(rq); if (delta) atomic_long_add(delta, &calc_load_tasks); } static void put_prev_task_fake(struct rq *rq, struct task_struct *prev) { } static const struct sched_class fake_sched_class = { .put_prev_task = put_prev_task_fake, }; static struct task_struct fake_task = { /* * Avoid pull_{rt,dl}_task() */ .prio = MAX_PRIO + 1, .sched_class = &fake_sched_class, }; /* * Migrate all tasks from the rq, sleeping tasks will be migrated by * try_to_wake_up()->select_task_rq(). * * Called with rq->lock held even though we'er in stop_machine() and * there's no concurrency possible, we hold the required locks anyway * because of lock validation efforts. */ static void migrate_tasks(unsigned int dead_cpu) { struct rq *rq = cpu_rq(dead_cpu); struct task_struct *next, *stop = rq->stop; int dest_cpu; /* * Fudge the rq selection such that the below task selection loop * doesn't get stuck on the currently eligible stop task. * * We're currently inside stop_machine() and the rq is either stuck * in the stop_machine_cpu_stop() loop, or we're executing this code, * either way we should never end up calling schedule() until we're * done here. */ rq->stop = NULL; /* * put_prev_task() and pick_next_task() sched * class method both need to have an up-to-date * value of rq->clock[_task] */ update_rq_clock(rq); for ( ; ; ) { /* * There's this thread running, bail when that's the only * remaining thread. */ if (rq->nr_running == 1) break; next = pick_next_task(rq, &fake_task); BUG_ON(!next); next->sched_class->put_prev_task(rq, next); /* Find suitable destination for @next, with force if needed. */ dest_cpu = select_fallback_rq(dead_cpu, next); raw_spin_unlock(&rq->lock); __migrate_task(next, dead_cpu, dest_cpu); raw_spin_lock(&rq->lock); } rq->stop = stop; } #endif /* CONFIG_HOTPLUG_CPU */ #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) static struct ctl_table sd_ctl_dir[] = { { .procname = "sched_domain", .mode = 0555, }, {} }; static struct ctl_table sd_ctl_root[] = { { .procname = "kernel", .mode = 0555, .child = sd_ctl_dir, }, {} }; static struct ctl_table *sd_alloc_ctl_entry(int n) { struct ctl_table *entry = kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); return entry; } static void sd_free_ctl_entry(struct ctl_table **tablep) { struct ctl_table *entry; /* * In the intermediate directories, both the child directory and * procname are dynamically allocated and could fail but the mode * will always be set. In the lowest directory the names are * static strings and all have proc handlers. */ for (entry = *tablep; entry->mode; entry++) { if (entry->child) sd_free_ctl_entry(&entry->child); if (entry->proc_handler == NULL) kfree(entry->procname); } kfree(*tablep); *tablep = NULL; } static int min_load_idx = 0; static int max_load_idx = CPU_LOAD_IDX_MAX-1; static void set_table_entry(struct ctl_table *entry, const char *procname, void *data, int maxlen, umode_t mode, proc_handler *proc_handler, bool load_idx) { entry->procname = procname; entry->data = data; entry->maxlen = maxlen; entry->mode = mode; entry->proc_handler = proc_handler; if (load_idx) { entry->extra1 = &min_load_idx; entry->extra2 = &max_load_idx; } } static struct ctl_table * sd_alloc_ctl_domain_table(struct sched_domain *sd) { struct ctl_table *table = sd_alloc_ctl_entry(14); if (table == NULL) return NULL; set_table_entry(&table[0], "min_interval", &sd->min_interval, sizeof(long), 0644, proc_doulongvec_minmax, false); set_table_entry(&table[1], "max_interval", &sd->max_interval, sizeof(long), 0644, proc_doulongvec_minmax, false); set_table_entry(&table[2], "busy_idx", &sd->busy_idx, sizeof(int), 0644, proc_dointvec_minmax, true); set_table_entry(&table[3], "idle_idx", &sd->idle_idx, sizeof(int), 0644, proc_dointvec_minmax, true); set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, sizeof(int), 0644, proc_dointvec_minmax, true); set_table_entry(&table[5], "wake_idx", &sd->wake_idx, sizeof(int), 0644, proc_dointvec_minmax, true); set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, sizeof(int), 0644, proc_dointvec_minmax, true); set_table_entry(&table[7], "busy_factor", &sd->busy_factor, sizeof(int), 0644, proc_dointvec_minmax, false); set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, sizeof(int), 0644, proc_dointvec_minmax, false); set_table_entry(&table[9], "cache_nice_tries", &sd->cache_nice_tries, sizeof(int), 0644, proc_dointvec_minmax, false); set_table_entry(&table[10], "flags", &sd->flags, sizeof(int), 0644, proc_dointvec_minmax, false); set_table_entry(&table[11], "max_newidle_lb_cost", &sd->max_newidle_lb_cost, sizeof(long), 0644, proc_doulongvec_minmax, false); set_table_entry(&table[12], "name", sd->name, CORENAME_MAX_SIZE, 0444, proc_dostring, false); /* &table[13] is terminator */ return table; } static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu) { struct ctl_table *entry, *table; struct sched_domain *sd; int domain_num = 0, i; char buf[32]; for_each_domain(cpu, sd) domain_num++; entry = table = sd_alloc_ctl_entry(domain_num + 1); if (table == NULL) return NULL; i = 0; for_each_domain(cpu, sd) { snprintf(buf, 32, "domain%d", i); entry->procname = kstrdup(buf, GFP_KERNEL); entry->mode = 0555; entry->child = sd_alloc_ctl_domain_table(sd); entry++; i++; } return table; } static struct ctl_table_header *sd_sysctl_header; static void register_sched_domain_sysctl(void) { int i, cpu_num = num_possible_cpus(); struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); char buf[32]; WARN_ON(sd_ctl_dir[0].child); sd_ctl_dir[0].child = entry; if (entry == NULL) return; for_each_possible_cpu(i) { snprintf(buf, 32, "cpu%d", i); entry->procname = kstrdup(buf, GFP_KERNEL); entry->mode = 0555; entry->child = sd_alloc_ctl_cpu_table(i); entry++; } WARN_ON(sd_sysctl_header); sd_sysctl_header = register_sysctl_table(sd_ctl_root); } /* may be called multiple times per register */ static void unregister_sched_domain_sysctl(void) { if (sd_sysctl_header) unregister_sysctl_table(sd_sysctl_header); sd_sysctl_header = NULL; if (sd_ctl_dir[0].child) sd_free_ctl_entry(&sd_ctl_dir[0].child); } #else static void register_sched_domain_sysctl(void) { } static void unregister_sched_domain_sysctl(void) { } #endif static void set_rq_online(struct rq *rq) { if (!rq->online) { const struct sched_class *class; cpumask_set_cpu(rq->cpu, rq->rd->online); rq->online = 1; for_each_class(class) { if (class->rq_online) class->rq_online(rq); } } } static void set_rq_offline(struct rq *rq) { if (rq->online) { const struct sched_class *class; for_each_class(class) { if (class->rq_offline) class->rq_offline(rq); } cpumask_clear_cpu(rq->cpu, rq->rd->online); rq->online = 0; } } /* * migration_call - callback that gets triggered when a CPU is added. * Here we can start up the necessary migration thread for the new CPU. */ static int migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) { int cpu = (long)hcpu; unsigned long flags; struct rq *rq = cpu_rq(cpu); switch (action & ~CPU_TASKS_FROZEN) { case CPU_UP_PREPARE: rq->calc_load_update = calc_load_update; break; case CPU_ONLINE: /* Update our root-domain */ raw_spin_lock_irqsave(&rq->lock, flags); if (rq->rd) { BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); set_rq_online(rq); } raw_spin_unlock_irqrestore(&rq->lock, flags); break; #ifdef CONFIG_HOTPLUG_CPU case CPU_DYING: sched_ttwu_pending(); /* Update our root-domain */ raw_spin_lock_irqsave(&rq->lock, flags); if (rq->rd) { BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); set_rq_offline(rq); } migrate_tasks(cpu); BUG_ON(rq->nr_running != 1); /* the migration thread */ raw_spin_unlock_irqrestore(&rq->lock, flags); break; case CPU_DEAD: calc_load_migrate(rq); break; #endif } update_max_interval(); return NOTIFY_OK; } /* * Register at high priority so that task migration (migrate_all_tasks) * happens before everything else. This has to be lower priority than * the notifier in the perf_event subsystem, though. */ static struct notifier_block migration_notifier = { .notifier_call = migration_call, .priority = CPU_PRI_MIGRATION, }; static void __cpuinit set_cpu_rq_start_time(void) { int cpu = smp_processor_id(); struct rq *rq = cpu_rq(cpu); rq->age_stamp = sched_clock_cpu(cpu); } static int sched_cpu_active(struct notifier_block *nfb, unsigned long action, void *hcpu) { switch (action & ~CPU_TASKS_FROZEN) { case CPU_STARTING: set_cpu_rq_start_time(); return NOTIFY_OK; case CPU_ONLINE: /* * At this point a starting CPU has marked itself as online via * set_cpu_online(). But it might not yet have marked itself * as active, which is essential from here on. * * Thus, fall-through and help the starting CPU along. */ case CPU_DOWN_FAILED: set_cpu_active((long)hcpu, true); return NOTIFY_OK; default: return NOTIFY_DONE; } } static int sched_cpu_inactive(struct notifier_block *nfb, unsigned long action, void *hcpu) { switch (action & ~CPU_TASKS_FROZEN) { case CPU_DOWN_PREPARE: set_cpu_active((long)hcpu, false); return NOTIFY_OK; default: return NOTIFY_DONE; } } static int __init migration_init(void) { void *cpu = (void *)(long)smp_processor_id(); int err; /* Initialize migration for the boot CPU */ err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); BUG_ON(err == NOTIFY_BAD); migration_call(&migration_notifier, CPU_ONLINE, cpu); register_cpu_notifier(&migration_notifier); /* Register cpu active notifiers */ cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); return 0; } early_initcall(migration_init); #endif #ifdef CONFIG_SMP static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ #ifdef CONFIG_SCHED_DEBUG static __read_mostly int sched_debug_enabled; static int __init sched_debug_setup(char *str) { sched_debug_enabled = 1; return 0; } early_param("sched_debug", sched_debug_setup); static inline bool sched_debug(void) { return sched_debug_enabled; } static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, struct cpumask *groupmask) { struct sched_group *group = sd->groups; cpumask_clear(groupmask); printk(KERN_DEBUG "%*s domain %d: ", level, "", level); if (!(sd->flags & SD_LOAD_BALANCE)) { printk("does not load-balance\n"); if (sd->parent) printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" " has parent"); return -1; } printk(KERN_CONT "span %*pbl level %s\n", cpumask_pr_args(sched_domain_span(sd)), sd->name); if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { printk(KERN_ERR "ERROR: domain->span does not contain " "CPU%d\n", cpu); } if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { printk(KERN_ERR "ERROR: domain->groups does not contain" " CPU%d\n", cpu); } printk(KERN_DEBUG "%*s groups:", level + 1, ""); do { if (!group) { printk("\n"); printk(KERN_ERR "ERROR: group is NULL\n"); break; } if (!cpumask_weight(sched_group_cpus(group))) { printk(KERN_CONT "\n"); printk(KERN_ERR "ERROR: empty group\n"); break; } if (!(sd->flags & SD_OVERLAP) && cpumask_intersects(groupmask, sched_group_cpus(group))) { printk(KERN_CONT "\n"); printk(KERN_ERR "ERROR: repeated CPUs\n"); break; } cpumask_or(groupmask, groupmask, sched_group_cpus(group)); printk(KERN_CONT " %*pbl", cpumask_pr_args(sched_group_cpus(group))); if (group->sgc->capacity != SCHED_CAPACITY_SCALE) { printk(KERN_CONT " (cpu_capacity = %d)", group->sgc->capacity); } group = group->next; } while (group != sd->groups); printk(KERN_CONT "\n"); if (!cpumask_equal(sched_domain_span(sd), groupmask)) printk(KERN_ERR "ERROR: groups don't span domain->span\n"); if (sd->parent && !cpumask_subset(groupmask, sched_domain_span(sd->parent))) printk(KERN_ERR "ERROR: parent span is not a superset " "of domain->span\n"); return 0; } static void sched_domain_debug(struct sched_domain *sd, int cpu) { int level = 0; if (!sched_debug_enabled) return; if (!sd) { printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); return; } printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); for (;;) { if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) break; level++; sd = sd->parent; if (!sd) break; } } #else /* !CONFIG_SCHED_DEBUG */ # define sched_domain_debug(sd, cpu) do { } while (0) static inline bool sched_debug(void) { return false; } #endif /* CONFIG_SCHED_DEBUG */ static int sd_degenerate(struct sched_domain *sd) { if (cpumask_weight(sched_domain_span(sd)) == 1) return 1; /* Following flags need at least 2 groups */ if (sd->flags & (SD_LOAD_BALANCE | SD_BALANCE_NEWIDLE | SD_BALANCE_FORK | SD_BALANCE_EXEC | SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES | SD_SHARE_POWERDOMAIN)) { if (sd->groups != sd->groups->next) return 0; } /* Following flags don't use groups */ if (sd->flags & (SD_WAKE_AFFINE)) return 0; return 1; } static int sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) { unsigned long cflags = sd->flags, pflags = parent->flags; if (sd_degenerate(parent)) return 1; if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) return 0; /* Flags needing groups don't count if only 1 group in parent */ if (parent->groups == parent->groups->next) { pflags &= ~(SD_LOAD_BALANCE | SD_BALANCE_NEWIDLE | SD_BALANCE_FORK | SD_BALANCE_EXEC | SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES | SD_PREFER_SIBLING | SD_SHARE_POWERDOMAIN); if (nr_node_ids == 1) pflags &= ~SD_SERIALIZE; } if (~cflags & pflags) return 0; return 1; } static void free_rootdomain(struct rcu_head *rcu) { struct root_domain *rd = container_of(rcu, struct root_domain, rcu); cpupri_cleanup(&rd->cpupri); cpudl_cleanup(&rd->cpudl); free_cpumask_var(rd->dlo_mask); free_cpumask_var(rd->rto_mask); free_cpumask_var(rd->online); free_cpumask_var(rd->span); kfree(rd); } static void rq_attach_root(struct rq *rq, struct root_domain *rd) { struct root_domain *old_rd = NULL; unsigned long flags; raw_spin_lock_irqsave(&rq->lock, flags); if (rq->rd) { old_rd = rq->rd; if (cpumask_test_cpu(rq->cpu, old_rd->online)) set_rq_offline(rq); cpumask_clear_cpu(rq->cpu, old_rd->span); /* * If we dont want to free the old_rd yet then * set old_rd to NULL to skip the freeing later * in this function: */ if (!atomic_dec_and_test(&old_rd->refcount)) old_rd = NULL; } atomic_inc(&rd->refcount); rq->rd = rd; cpumask_set_cpu(rq->cpu, rd->span); if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) set_rq_online(rq); raw_spin_unlock_irqrestore(&rq->lock, flags); if (old_rd) call_rcu_sched(&old_rd->rcu, free_rootdomain); } static int init_rootdomain(struct root_domain *rd) { memset(rd, 0, sizeof(*rd)); if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) goto out; if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) goto free_span; if (!alloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) goto free_online; if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) goto free_dlo_mask; init_dl_bw(&rd->dl_bw); if (cpudl_init(&rd->cpudl) != 0) goto free_dlo_mask; if (cpupri_init(&rd->cpupri) != 0) goto free_rto_mask; return 0; free_rto_mask: free_cpumask_var(rd->rto_mask); free_dlo_mask: free_cpumask_var(rd->dlo_mask); free_online: free_cpumask_var(rd->online); free_span: free_cpumask_var(rd->span); out: return -ENOMEM; } /* * By default the system creates a single root-domain with all cpus as * members (mimicking the global state we have today). */ struct root_domain def_root_domain; static void init_defrootdomain(void) { init_rootdomain(&def_root_domain); atomic_set(&def_root_domain.refcount, 1); } static struct root_domain *alloc_rootdomain(void) { struct root_domain *rd; rd = kmalloc(sizeof(*rd), GFP_KERNEL); if (!rd) return NULL; if (init_rootdomain(rd) != 0) { kfree(rd); return NULL; } return rd; } static void free_sched_groups(struct sched_group *sg, int free_sgc) { struct sched_group *tmp, *first; if (!sg) return; first = sg; do { tmp = sg->next; if (free_sgc && atomic_dec_and_test(&sg->sgc->ref)) kfree(sg->sgc); kfree(sg); sg = tmp; } while (sg != first); } static void free_sched_domain(struct rcu_head *rcu) { struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); /* * If its an overlapping domain it has private groups, iterate and * nuke them all. */ if (sd->flags & SD_OVERLAP) { free_sched_groups(sd->groups, 1); } else if (atomic_dec_and_test(&sd->groups->ref)) { kfree(sd->groups->sgc); kfree(sd->groups); } kfree(sd); } static void destroy_sched_domain(struct sched_domain *sd, int cpu) { call_rcu(&sd->rcu, free_sched_domain); } static void destroy_sched_domains(struct sched_domain *sd, int cpu) { for (; sd; sd = sd->parent) destroy_sched_domain(sd, cpu); } /* * Keep a special pointer to the highest sched_domain that has * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this * allows us to avoid some pointer chasing select_idle_sibling(). * * Also keep a unique ID per domain (we use the first cpu number in * the cpumask of the domain), this allows us to quickly tell if * two cpus are in the same cache domain, see cpus_share_cache(). */ DEFINE_PER_CPU(struct sched_domain *, sd_llc); DEFINE_PER_CPU(int, sd_llc_size); DEFINE_PER_CPU(int, sd_llc_id); DEFINE_PER_CPU(struct sched_domain *, sd_numa); DEFINE_PER_CPU(struct sched_domain *, sd_busy); DEFINE_PER_CPU(struct sched_domain *, sd_asym); static void update_top_cache_domain(int cpu) { struct sched_domain *sd; struct sched_domain *busy_sd = NULL; int id = cpu; int size = 1; sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); if (sd) { id = cpumask_first(sched_domain_span(sd)); size = cpumask_weight(sched_domain_span(sd)); busy_sd = sd->parent; /* sd_busy */ } rcu_assign_pointer(per_cpu(sd_busy, cpu), busy_sd); rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); per_cpu(sd_llc_size, cpu) = size; per_cpu(sd_llc_id, cpu) = id; sd = lowest_flag_domain(cpu, SD_NUMA); rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); sd = highest_flag_domain(cpu, SD_ASYM_PACKING); rcu_assign_pointer(per_cpu(sd_asym, cpu), sd); } /* * Attach the domain 'sd' to 'cpu' as its base domain. Callers must * hold the hotplug lock. */ static void cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) { struct rq *rq = cpu_rq(cpu); struct sched_domain *tmp; /* Remove the sched domains which do not contribute to scheduling. */ for (tmp = sd; tmp; ) { struct sched_domain *parent = tmp->parent; if (!parent) break; if (sd_parent_degenerate(tmp, parent)) { tmp->parent = parent->parent; if (parent->parent) parent->parent->child = tmp; /* * Transfer SD_PREFER_SIBLING down in case of a * degenerate parent; the spans match for this * so the property transfers. */ if (parent->flags & SD_PREFER_SIBLING) tmp->flags |= SD_PREFER_SIBLING; destroy_sched_domain(parent, cpu); } else tmp = tmp->parent; } if (sd && sd_degenerate(sd)) { tmp = sd; sd = sd->parent; destroy_sched_domain(tmp, cpu); if (sd) sd->child = NULL; } sched_domain_debug(sd, cpu); rq_attach_root(rq, rd); tmp = rq->sd; rcu_assign_pointer(rq->sd, sd); destroy_sched_domains(tmp, cpu); update_top_cache_domain(cpu); } /* Setup the mask of cpus configured for isolated domains */ static int __init isolated_cpu_setup(char *str) { alloc_bootmem_cpumask_var(&cpu_isolated_map); cpulist_parse(str, cpu_isolated_map); return 1; } __setup("isolcpus=", isolated_cpu_setup); struct s_data { struct sched_domain ** __percpu sd; struct root_domain *rd; }; enum s_alloc { sa_rootdomain, sa_sd, sa_sd_storage, sa_none, }; /* * Build an iteration mask that can exclude certain CPUs from the upwards * domain traversal. * * Only CPUs that can arrive at this group should be considered to continue * balancing. * * Asymmetric node setups can result in situations where the domain tree is of * unequal depth, make sure to skip domains that already cover the entire * range. * * In that case build_sched_domains() will have terminated the iteration early * and our sibling sd spans will be empty. Domains should always include the * cpu they're built on, so check that. * */ static void build_group_mask(struct sched_domain *sd, struct sched_group *sg) { const struct cpumask *sg_span = sched_group_cpus(sg); struct sd_data *sdd = sd->private; struct sched_domain *sibling; int i; for_each_cpu(i, sg_span) { sibling = *per_cpu_ptr(sdd->sd, i); /* * Can happen in the asymmetric case, where these siblings are * unused. The mask will not be empty because those CPUs that * do have the top domain _should_ span the domain. */ if (!sibling->child) continue; /* If we would not end up here, we can't continue from here */ if (!cpumask_equal(sg_span, sched_domain_span(sibling->child))) continue; cpumask_set_cpu(i, sched_group_mask(sg)); } /* We must not have empty masks here */ WARN_ON_ONCE(cpumask_empty(sched_group_mask(sg))); } /* * Return the canonical balance cpu for this group, this is the first cpu * of this group that's also in the iteration mask. */ int group_balance_cpu(struct sched_group *sg) { return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg)); } static int build_overlap_sched_groups(struct sched_domain *sd, int cpu) { struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; const struct cpumask *span = sched_domain_span(sd); struct cpumask *covered = sched_domains_tmpmask; struct sd_data *sdd = sd->private; struct sched_domain *sibling; int i; cpumask_clear(covered); for_each_cpu(i, span) { struct cpumask *sg_span; if (cpumask_test_cpu(i, covered)) continue; sibling = *per_cpu_ptr(sdd->sd, i); /* See the comment near build_group_mask(). */ if (!cpumask_test_cpu(i, sched_domain_span(sibling))) continue; sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), GFP_KERNEL, cpu_to_node(cpu)); if (!sg) goto fail; sg_span = sched_group_cpus(sg); if (sibling->child) cpumask_copy(sg_span, sched_domain_span(sibling->child)); else cpumask_set_cpu(i, sg_span); cpumask_or(covered, covered, sg_span); sg->sgc = *per_cpu_ptr(sdd->sgc, i); if (atomic_inc_return(&sg->sgc->ref) == 1) build_group_mask(sd, sg); /* * Initialize sgc->capacity such that even if we mess up the * domains and no possible iteration will get us here, we won't * die on a /0 trap. */ sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span); /* * Make sure the first group of this domain contains the * canonical balance cpu. Otherwise the sched_domain iteration * breaks. See update_sg_lb_stats(). */ if ((!groups && cpumask_test_cpu(cpu, sg_span)) || group_balance_cpu(sg) == cpu) groups = sg; if (!first) first = sg; if (last) last->next = sg; last = sg; last->next = first; } sd->groups = groups; return 0; fail: free_sched_groups(first, 0); return -ENOMEM; } static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) { struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); struct sched_domain *child = sd->child; if (child) cpu = cpumask_first(sched_domain_span(child)); if (sg) { *sg = *per_cpu_ptr(sdd->sg, cpu); (*sg)->sgc = *per_cpu_ptr(sdd->sgc, cpu); atomic_set(&(*sg)->sgc->ref, 1); /* for claim_allocations */ } return cpu; } /* * build_sched_groups will build a circular linked list of the groups * covered by the given span, and will set each group's ->cpumask correctly, * and ->cpu_capacity to 0. * * Assumes the sched_domain tree is fully constructed */ static int build_sched_groups(struct sched_domain *sd, int cpu) { struct sched_group *first = NULL, *last = NULL; struct sd_data *sdd = sd->private; const struct cpumask *span = sched_domain_span(sd); struct cpumask *covered; int i; get_group(cpu, sdd, &sd->groups); atomic_inc(&sd->groups->ref); if (cpu != cpumask_first(span)) return 0; lockdep_assert_held(&sched_domains_mutex); covered = sched_domains_tmpmask; cpumask_clear(covered); for_each_cpu(i, span) { struct sched_group *sg; int group, j; if (cpumask_test_cpu(i, covered)) continue; group = get_group(i, sdd, &sg); cpumask_setall(sched_group_mask(sg)); for_each_cpu(j, span) { if (get_group(j, sdd, NULL) != group) continue; cpumask_set_cpu(j, covered); cpumask_set_cpu(j, sched_group_cpus(sg)); } if (!first) first = sg; if (last) last->next = sg; last = sg; } last->next = first; return 0; } /* * Initialize sched groups cpu_capacity. * * cpu_capacity indicates the capacity of sched group, which is used while * distributing the load between different sched groups in a sched domain. * Typically cpu_capacity for all the groups in a sched domain will be same * unless there are asymmetries in the topology. If there are asymmetries, * group having more cpu_capacity will pickup more load compared to the * group having less cpu_capacity. */ static void init_sched_groups_capacity(int cpu, struct sched_domain *sd) { struct sched_group *sg = sd->groups; WARN_ON(!sg); do { sg->group_weight = cpumask_weight(sched_group_cpus(sg)); sg = sg->next; } while (sg != sd->groups); if (cpu != group_balance_cpu(sg)) return; update_group_capacity(sd, cpu); atomic_set(&sg->sgc->nr_busy_cpus, sg->group_weight); } /* * Initializers for schedule domains * Non-inlined to reduce accumulated stack pressure in build_sched_domains() */ static int default_relax_domain_level = -1; int sched_domain_level_max; static int __init setup_relax_domain_level(char *str) { if (kstrtoint(str, 0, &default_relax_domain_level)) pr_warn("Unable to set relax_domain_level\n"); return 1; } __setup("relax_domain_level=", setup_relax_domain_level); static void set_domain_attribute(struct sched_domain *sd, struct sched_domain_attr *attr) { int request; if (!attr || attr->relax_domain_level < 0) { if (default_relax_domain_level < 0) return; else request = default_relax_domain_level; } else request = attr->relax_domain_level; if (request < sd->level) { /* turn off idle balance on this domain */ sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); } else { /* turn on idle balance on this domain */ sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); } } static void __sdt_free(const struct cpumask *cpu_map); static int __sdt_alloc(const struct cpumask *cpu_map); static void __free_domain_allocs(struct s_data *d, enum s_alloc what, const struct cpumask *cpu_map) { switch (what) { case sa_rootdomain: if (!atomic_read(&d->rd->refcount)) free_rootdomain(&d->rd->rcu); /* fall through */ case sa_sd: free_percpu(d->sd); /* fall through */ case sa_sd_storage: __sdt_free(cpu_map); /* fall through */ case sa_none: break; } } static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, const struct cpumask *cpu_map) { memset(d, 0, sizeof(*d)); if (__sdt_alloc(cpu_map)) return sa_sd_storage; d->sd = alloc_percpu(struct sched_domain *); if (!d->sd) return sa_sd_storage; d->rd = alloc_rootdomain(); if (!d->rd) return sa_sd; return sa_rootdomain; } /* * NULL the sd_data elements we've used to build the sched_domain and * sched_group structure so that the subsequent __free_domain_allocs() * will not free the data we're using. */ static void claim_allocations(int cpu, struct sched_domain *sd) { struct sd_data *sdd = sd->private; WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); *per_cpu_ptr(sdd->sd, cpu) = NULL; if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) *per_cpu_ptr(sdd->sg, cpu) = NULL; if (atomic_read(&(*per_cpu_ptr(sdd->sgc, cpu))->ref)) *per_cpu_ptr(sdd->sgc, cpu) = NULL; } #ifdef CONFIG_NUMA static int sched_domains_numa_levels; enum numa_topology_type sched_numa_topology_type; static int *sched_domains_numa_distance; int sched_max_numa_distance; static struct cpumask ***sched_domains_numa_masks; static int sched_domains_curr_level; #endif /* * SD_flags allowed in topology descriptions. * * SD_SHARE_CPUCAPACITY - describes SMT topologies * SD_SHARE_PKG_RESOURCES - describes shared caches * SD_NUMA - describes NUMA topologies * SD_SHARE_POWERDOMAIN - describes shared power domain * * Odd one out: * SD_ASYM_PACKING - describes SMT quirks */ #define TOPOLOGY_SD_FLAGS \ (SD_SHARE_CPUCAPACITY | \ SD_SHARE_PKG_RESOURCES | \ SD_NUMA | \ SD_ASYM_PACKING | \ SD_SHARE_POWERDOMAIN) static struct sched_domain * sd_init(struct sched_domain_topology_level *tl, int cpu) { struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); int sd_weight, sd_flags = 0; #ifdef CONFIG_NUMA /* * Ugly hack to pass state to sd_numa_mask()... */ sched_domains_curr_level = tl->numa_level; #endif sd_weight = cpumask_weight(tl->mask(cpu)); if (tl->sd_flags) sd_flags = (*tl->sd_flags)(); if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS, "wrong sd_flags in topology description\n")) sd_flags &= ~TOPOLOGY_SD_FLAGS; *sd = (struct sched_domain){ .min_interval = sd_weight, .max_interval = 2*sd_weight, .busy_factor = 32, .imbalance_pct = 125, .cache_nice_tries = 0, .busy_idx = 0, .idle_idx = 0, .newidle_idx = 0, .wake_idx = 0, .forkexec_idx = 0, .flags = 1*SD_LOAD_BALANCE | 1*SD_BALANCE_NEWIDLE | 1*SD_BALANCE_EXEC | 1*SD_BALANCE_FORK | 0*SD_BALANCE_WAKE | 1*SD_WAKE_AFFINE | 0*SD_SHARE_CPUCAPACITY | 0*SD_SHARE_PKG_RESOURCES | 0*SD_SERIALIZE | 0*SD_PREFER_SIBLING | 0*SD_NUMA | sd_flags , .last_balance = jiffies, .balance_interval = sd_weight, .smt_gain = 0, .max_newidle_lb_cost = 0, .next_decay_max_lb_cost = jiffies, #ifdef CONFIG_SCHED_DEBUG .name = tl->name, #endif }; /* * Convert topological properties into behaviour. */ if (sd->flags & SD_SHARE_CPUCAPACITY) { sd->flags |= SD_PREFER_SIBLING; sd->imbalance_pct = 110; sd->smt_gain = 1178; /* ~15% */ } else if (sd->flags & SD_SHARE_PKG_RESOURCES) { sd->imbalance_pct = 117; sd->cache_nice_tries = 1; sd->busy_idx = 2; #ifdef CONFIG_NUMA } else if (sd->flags & SD_NUMA) { sd->cache_nice_tries = 2; sd->busy_idx = 3; sd->idle_idx = 2; sd->flags |= SD_SERIALIZE; if (sched_domains_numa_distance[tl->numa_level] > RECLAIM_DISTANCE) { sd->flags &= ~(SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE); } #endif } else { sd->flags |= SD_PREFER_SIBLING; sd->cache_nice_tries = 1; sd->busy_idx = 2; sd->idle_idx = 1; } sd->private = &tl->data; return sd; } /* * Topology list, bottom-up. */ static struct sched_domain_topology_level default_topology[] = { #ifdef CONFIG_SCHED_SMT { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) }, #endif #ifdef CONFIG_SCHED_MC { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) }, #endif { cpu_cpu_mask, SD_INIT_NAME(DIE) }, { NULL, }, }; struct sched_domain_topology_level *sched_domain_topology = default_topology; #define for_each_sd_topology(tl) \ for (tl = sched_domain_topology; tl->mask; tl++) void set_sched_topology(struct sched_domain_topology_level *tl) { sched_domain_topology = tl; } #ifdef CONFIG_NUMA static const struct cpumask *sd_numa_mask(int cpu) { return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; } static void sched_numa_warn(const char *str) { static int done = false; int i,j; if (done) return; done = true; printk(KERN_WARNING "ERROR: %s\n\n", str); for (i = 0; i < nr_node_ids; i++) { printk(KERN_WARNING " "); for (j = 0; j < nr_node_ids; j++) printk(KERN_CONT "%02d ", node_distance(i,j)); printk(KERN_CONT "\n"); } printk(KERN_WARNING "\n"); } bool find_numa_distance(int distance) { int i; if (distance == node_distance(0, 0)) return true; for (i = 0; i < sched_domains_numa_levels; i++) { if (sched_domains_numa_distance[i] == distance) return true; } return false; } /* * A system can have three types of NUMA topology: * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes * NUMA_BACKPLANE: nodes can reach other nodes through a backplane * * The difference between a glueless mesh topology and a backplane * topology lies in whether communication between not directly * connected nodes goes through intermediary nodes (where programs * could run), or through backplane controllers. This affects * placement of programs. * * The type of topology can be discerned with the following tests: * - If the maximum distance between any nodes is 1 hop, the system * is directly connected. * - If for two nodes A and B, located N > 1 hops away from each other, * there is an intermediary node C, which is < N hops away from both * nodes A and B, the system is a glueless mesh. */ static void init_numa_topology_type(void) { int a, b, c, n; n = sched_max_numa_distance; if (n <= 1) sched_numa_topology_type = NUMA_DIRECT; for_each_online_node(a) { for_each_online_node(b) { /* Find two nodes furthest removed from each other. */ if (node_distance(a, b) < n) continue; /* Is there an intermediary node between a and b? */ for_each_online_node(c) { if (node_distance(a, c) < n && node_distance(b, c) < n) { sched_numa_topology_type = NUMA_GLUELESS_MESH; return; } } sched_numa_topology_type = NUMA_BACKPLANE; return; } } } static void sched_init_numa(void) { int next_distance, curr_distance = node_distance(0, 0); struct sched_domain_topology_level *tl; int level = 0; int i, j, k; sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL); if (!sched_domains_numa_distance) return; /* * O(nr_nodes^2) deduplicating selection sort -- in order to find the * unique distances in the node_distance() table. * * Assumes node_distance(0,j) includes all distances in * node_distance(i,j) in order to avoid cubic time. */ next_distance = curr_distance; for (i = 0; i < nr_node_ids; i++) { for (j = 0; j < nr_node_ids; j++) { for (k = 0; k < nr_node_ids; k++) { int distance = node_distance(i, k); if (distance > curr_distance && (distance < next_distance || next_distance == curr_distance)) next_distance = distance; /* * While not a strong assumption it would be nice to know * about cases where if node A is connected to B, B is not * equally connected to A. */ if (sched_debug() && node_distance(k, i) != distance) sched_numa_warn("Node-distance not symmetric"); if (sched_debug() && i && !find_numa_distance(distance)) sched_numa_warn("Node-0 not representative"); } if (next_distance != curr_distance) { sched_domains_numa_distance[level++] = next_distance; sched_domains_numa_levels = level; curr_distance = next_distance; } else break; } /* * In case of sched_debug() we verify the above assumption. */ if (!sched_debug()) break; } if (!level) return; /* * 'level' contains the number of unique distances, excluding the * identity distance node_distance(i,i). * * The sched_domains_numa_distance[] array includes the actual distance * numbers. */ /* * Here, we should temporarily reset sched_domains_numa_levels to 0. * If it fails to allocate memory for array sched_domains_numa_masks[][], * the array will contain less then 'level' members. This could be * dangerous when we use it to iterate array sched_domains_numa_masks[][] * in other functions. * * We reset it to 'level' at the end of this function. */ sched_domains_numa_levels = 0; sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); if (!sched_domains_numa_masks) return; /* * Now for each level, construct a mask per node which contains all * cpus of nodes that are that many hops away from us. */ for (i = 0; i < level; i++) { sched_domains_numa_masks[i] = kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); if (!sched_domains_numa_masks[i]) return; for (j = 0; j < nr_node_ids; j++) { struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); if (!mask) return; sched_domains_numa_masks[i][j] = mask; for_each_node(k) { if (node_distance(j, k) > sched_domains_numa_distance[i]) continue; cpumask_or(mask, mask, cpumask_of_node(k)); } } } /* Compute default topology size */ for (i = 0; sched_domain_topology[i].mask; i++); tl = kzalloc((i + level + 1) * sizeof(struct sched_domain_topology_level), GFP_KERNEL); if (!tl) return; /* * Copy the default topology bits.. */ for (i = 0; sched_domain_topology[i].mask; i++) tl[i] = sched_domain_topology[i]; /* * .. and append 'j' levels of NUMA goodness. */ for (j = 0; j < level; i++, j++) { tl[i] = (struct sched_domain_topology_level){ .mask = sd_numa_mask, .sd_flags = cpu_numa_flags, .flags = SDTL_OVERLAP, .numa_level = j, SD_INIT_NAME(NUMA) }; } sched_domain_topology = tl; sched_domains_numa_levels = level; sched_max_numa_distance = sched_domains_numa_distance[level - 1]; init_numa_topology_type(); } static void sched_domains_numa_masks_set(int cpu) { int i, j; int node = cpu_to_node(cpu); for (i = 0; i < sched_domains_numa_levels; i++) { for (j = 0; j < nr_node_ids; j++) { if (node_distance(j, node) <= sched_domains_numa_distance[i]) cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); } } } static void sched_domains_numa_masks_clear(int cpu) { int i, j; for (i = 0; i < sched_domains_numa_levels; i++) { for (j = 0; j < nr_node_ids; j++) cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); } } /* * Update sched_domains_numa_masks[level][node] array when new cpus * are onlined. */ static int sched_domains_numa_masks_update(struct notifier_block *nfb, unsigned long action, void *hcpu) { int cpu = (long)hcpu; switch (action & ~CPU_TASKS_FROZEN) { case CPU_ONLINE: sched_domains_numa_masks_set(cpu); break; case CPU_DEAD: sched_domains_numa_masks_clear(cpu); break; default: return NOTIFY_DONE; } return NOTIFY_OK; } #else static inline void sched_init_numa(void) { } static int sched_domains_numa_masks_update(struct notifier_block *nfb, unsigned long action, void *hcpu) { return 0; } #endif /* CONFIG_NUMA */ static int __sdt_alloc(const struct cpumask *cpu_map) { struct sched_domain_topology_level *tl; int j; for_each_sd_topology(tl) { struct sd_data *sdd = &tl->data; sdd->sd = alloc_percpu(struct sched_domain *); if (!sdd->sd) return -ENOMEM; sdd->sg = alloc_percpu(struct sched_group *); if (!sdd->sg) return -ENOMEM; sdd->sgc = alloc_percpu(struct sched_group_capacity *); if (!sdd->sgc) return -ENOMEM; for_each_cpu(j, cpu_map) { struct sched_domain *sd; struct sched_group *sg; struct sched_group_capacity *sgc; sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), GFP_KERNEL, cpu_to_node(j)); if (!sd) return -ENOMEM; *per_cpu_ptr(sdd->sd, j) = sd; sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), GFP_KERNEL, cpu_to_node(j)); if (!sg) return -ENOMEM; sg->next = sg; *per_cpu_ptr(sdd->sg, j) = sg; sgc = kzalloc_node(sizeof(struct sched_group_capacity) + cpumask_size(), GFP_KERNEL, cpu_to_node(j)); if (!sgc) return -ENOMEM; *per_cpu_ptr(sdd->sgc, j) = sgc; } } return 0; } static void __sdt_free(const struct cpumask *cpu_map) { struct sched_domain_topology_level *tl; int j; for_each_sd_topology(tl) { struct sd_data *sdd = &tl->data; for_each_cpu(j, cpu_map) { struct sched_domain *sd; if (sdd->sd) { sd = *per_cpu_ptr(sdd->sd, j); if (sd && (sd->flags & SD_OVERLAP)) free_sched_groups(sd->groups, 0); kfree(*per_cpu_ptr(sdd->sd, j)); } if (sdd->sg) kfree(*per_cpu_ptr(sdd->sg, j)); if (sdd->sgc) kfree(*per_cpu_ptr(sdd->sgc, j)); } free_percpu(sdd->sd); sdd->sd = NULL; free_percpu(sdd->sg); sdd->sg = NULL; free_percpu(sdd->sgc); sdd->sgc = NULL; } } struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, const struct cpumask *cpu_map, struct sched_domain_attr *attr, struct sched_domain *child, int cpu) { struct sched_domain *sd = sd_init(tl, cpu); if (!sd) return child; cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); if (child) { sd->level = child->level + 1; sched_domain_level_max = max(sched_domain_level_max, sd->level); child->parent = sd; sd->child = child; if (!cpumask_subset(sched_domain_span(child), sched_domain_span(sd))) { pr_err("BUG: arch topology borken\n"); #ifdef CONFIG_SCHED_DEBUG pr_err(" the %s domain not a subset of the %s domain\n", child->name, sd->name); #endif /* Fixup, ensure @sd has at least @child cpus. */ cpumask_or(sched_domain_span(sd), sched_domain_span(sd), sched_domain_span(child)); } } set_domain_attribute(sd, attr); return sd; } /* * Build sched domains for a given set of cpus and attach the sched domains * to the individual cpus */ static int build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *attr) { enum s_alloc alloc_state; struct sched_domain *sd; struct s_data d; int i, ret = -ENOMEM; alloc_state = __visit_domain_allocation_hell(&d, cpu_map); if (alloc_state != sa_rootdomain) goto error; /* Set up domains for cpus specified by the cpu_map. */ for_each_cpu(i, cpu_map) { struct sched_domain_topology_level *tl; sd = NULL; for_each_sd_topology(tl) { sd = build_sched_domain(tl, cpu_map, attr, sd, i); if (tl == sched_domain_topology) *per_cpu_ptr(d.sd, i) = sd; if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) sd->flags |= SD_OVERLAP; if (cpumask_equal(cpu_map, sched_domain_span(sd))) break; } } /* Build the groups for the domains */ for_each_cpu(i, cpu_map) { for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { sd->span_weight = cpumask_weight(sched_domain_span(sd)); if (sd->flags & SD_OVERLAP) { if (build_overlap_sched_groups(sd, i)) goto error; } else { if (build_sched_groups(sd, i)) goto error; } } } /* Calculate CPU capacity for physical packages and nodes */ for (i = nr_cpumask_bits-1; i >= 0; i--) { if (!cpumask_test_cpu(i, cpu_map)) continue; for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { claim_allocations(i, sd); init_sched_groups_capacity(i, sd); } } /* Attach the domains */ rcu_read_lock(); for_each_cpu(i, cpu_map) { sd = *per_cpu_ptr(d.sd, i); cpu_attach_domain(sd, d.rd, i); } rcu_read_unlock(); ret = 0; error: __free_domain_allocs(&d, alloc_state, cpu_map); return ret; } static cpumask_var_t *doms_cur; /* current sched domains */ static int ndoms_cur; /* number of sched domains in 'doms_cur' */ static struct sched_domain_attr *dattr_cur; /* attribues of custom domains in 'doms_cur' */ /* * Special case: If a kmalloc of a doms_cur partition (array of * cpumask) fails, then fallback to a single sched domain, * as determined by the single cpumask fallback_doms. */ static cpumask_var_t fallback_doms; /* * arch_update_cpu_topology lets virtualized architectures update the * cpu core maps. It is supposed to return 1 if the topology changed * or 0 if it stayed the same. */ int __weak arch_update_cpu_topology(void) { return 0; } cpumask_var_t *alloc_sched_domains(unsigned int ndoms) { int i; cpumask_var_t *doms; doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); if (!doms) return NULL; for (i = 0; i < ndoms; i++) { if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { free_sched_domains(doms, i); return NULL; } } return doms; } void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) { unsigned int i; for (i = 0; i < ndoms; i++) free_cpumask_var(doms[i]); kfree(doms); } /* * Set up scheduler domains and groups. Callers must hold the hotplug lock. * For now this just excludes isolated cpus, but could be used to * exclude other special cases in the future. */ static int init_sched_domains(const struct cpumask *cpu_map) { int err; arch_update_cpu_topology(); ndoms_cur = 1; doms_cur = alloc_sched_domains(ndoms_cur); if (!doms_cur) doms_cur = &fallback_doms; cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); err = build_sched_domains(doms_cur[0], NULL); register_sched_domain_sysctl(); return err; } /* * Detach sched domains from a group of cpus specified in cpu_map * These cpus will now be attached to the NULL domain */ static void detach_destroy_domains(const struct cpumask *cpu_map) { int i; rcu_read_lock(); for_each_cpu(i, cpu_map) cpu_attach_domain(NULL, &def_root_domain, i); rcu_read_unlock(); } /* handle null as "default" */ static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, struct sched_domain_attr *new, int idx_new) { struct sched_domain_attr tmp; /* fast path */ if (!new && !cur) return 1; tmp = SD_ATTR_INIT; return !memcmp(cur ? (cur + idx_cur) : &tmp, new ? (new + idx_new) : &tmp, sizeof(struct sched_domain_attr)); } /* * Partition sched domains as specified by the 'ndoms_new' * cpumasks in the array doms_new[] of cpumasks. This compares * doms_new[] to the current sched domain partitioning, doms_cur[]. * It destroys each deleted domain and builds each new domain. * * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. * The masks don't intersect (don't overlap.) We should setup one * sched domain for each mask. CPUs not in any of the cpumasks will * not be load balanced. If the same cpumask appears both in the * current 'doms_cur' domains and in the new 'doms_new', we can leave * it as it is. * * The passed in 'doms_new' should be allocated using * alloc_sched_domains. This routine takes ownership of it and will * free_sched_domains it when done with it. If the caller failed the * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, * and partition_sched_domains() will fallback to the single partition * 'fallback_doms', it also forces the domains to be rebuilt. * * If doms_new == NULL it will be replaced with cpu_online_mask. * ndoms_new == 0 is a special case for destroying existing domains, * and it will not create the default domain. * * Call with hotplug lock held */ void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], struct sched_domain_attr *dattr_new) { int i, j, n; int new_topology; mutex_lock(&sched_domains_mutex); /* always unregister in case we don't destroy any domains */ unregister_sched_domain_sysctl(); /* Let architecture update cpu core mappings. */ new_topology = arch_update_cpu_topology(); n = doms_new ? ndoms_new : 0; /* Destroy deleted domains */ for (i = 0; i < ndoms_cur; i++) { for (j = 0; j < n && !new_topology; j++) { if (cpumask_equal(doms_cur[i], doms_new[j]) && dattrs_equal(dattr_cur, i, dattr_new, j)) goto match1; } /* no match - a current sched domain not in new doms_new[] */ detach_destroy_domains(doms_cur[i]); match1: ; } n = ndoms_cur; if (doms_new == NULL) { n = 0; doms_new = &fallback_doms; cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); WARN_ON_ONCE(dattr_new); } /* Build new domains */ for (i = 0; i < ndoms_new; i++) { for (j = 0; j < n && !new_topology; j++) { if (cpumask_equal(doms_new[i], doms_cur[j]) && dattrs_equal(dattr_new, i, dattr_cur, j)) goto match2; } /* no match - add a new doms_new */ build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); match2: ; } /* Remember the new sched domains */ if (doms_cur != &fallback_doms) free_sched_domains(doms_cur, ndoms_cur); kfree(dattr_cur); /* kfree(NULL) is safe */ doms_cur = doms_new; dattr_cur = dattr_new; ndoms_cur = ndoms_new; register_sched_domain_sysctl(); mutex_unlock(&sched_domains_mutex); } static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */ /* * Update cpusets according to cpu_active mask. If cpusets are * disabled, cpuset_update_active_cpus() becomes a simple wrapper * around partition_sched_domains(). * * If we come here as part of a suspend/resume, don't touch cpusets because we * want to restore it back to its original state upon resume anyway. */ static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, void *hcpu) { switch (action) { case CPU_ONLINE_FROZEN: case CPU_DOWN_FAILED_FROZEN: /* * num_cpus_frozen tracks how many CPUs are involved in suspend * resume sequence. As long as this is not the last online * operation in the resume sequence, just build a single sched * domain, ignoring cpusets. */ partition_sched_domains(1, NULL, NULL); if (--num_cpus_frozen) break; /* * This is the last CPU online operation. So fall through and * restore the original sched domains by considering the * cpuset configurations. */ cpuset_force_rebuild(); case CPU_ONLINE: cpuset_update_active_cpus(true); break; default: return NOTIFY_DONE; } return NOTIFY_OK; } static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, void *hcpu) { unsigned long flags; long cpu = (long)hcpu; struct dl_bw *dl_b; bool overflow; int cpus; switch (action) { case CPU_DOWN_PREPARE: rcu_read_lock_sched(); dl_b = dl_bw_of(cpu); raw_spin_lock_irqsave(&dl_b->lock, flags); cpus = dl_bw_cpus(cpu); overflow = __dl_overflow(dl_b, cpus, 0, 0); raw_spin_unlock_irqrestore(&dl_b->lock, flags); rcu_read_unlock_sched(); if (overflow) return notifier_from_errno(-EBUSY); cpuset_update_active_cpus(false); break; case CPU_DOWN_PREPARE_FROZEN: num_cpus_frozen++; partition_sched_domains(1, NULL, NULL); break; default: return NOTIFY_DONE; } return NOTIFY_OK; } void __init sched_init_smp(void) { cpumask_var_t non_isolated_cpus; alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); alloc_cpumask_var(&fallback_doms, GFP_KERNEL); sched_init_numa(); /* * There's no userspace yet to cause hotplug operations; hence all the * cpu masks are stable and all blatant races in the below code cannot * happen. */ mutex_lock(&sched_domains_mutex); init_sched_domains(cpu_active_mask); cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); if (cpumask_empty(non_isolated_cpus)) cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); mutex_unlock(&sched_domains_mutex); hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE); hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); init_hrtick(); /* Move init over to a non-isolated CPU */ if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) BUG(); sched_init_granularity(); free_cpumask_var(non_isolated_cpus); init_sched_rt_class(); init_sched_dl_class(); } #else void __init sched_init_smp(void) { sched_init_granularity(); } #endif /* CONFIG_SMP */ const_debug unsigned int sysctl_timer_migration = 1; int in_sched_functions(unsigned long addr) { return in_lock_functions(addr) || (addr >= (unsigned long)__sched_text_start && addr < (unsigned long)__sched_text_end); } #ifdef CONFIG_CGROUP_SCHED /* * Default task group. * Every task in system belongs to this group at bootup. */ struct task_group root_task_group; LIST_HEAD(task_groups); #endif DECLARE_PER_CPU(cpumask_var_t, load_balance_mask); void __init sched_init(void) { int i, j; unsigned long alloc_size = 0, ptr; #ifdef CONFIG_FAIR_GROUP_SCHED alloc_size += 2 * nr_cpu_ids * sizeof(void **); #endif #ifdef CONFIG_RT_GROUP_SCHED alloc_size += 2 * nr_cpu_ids * sizeof(void **); #endif if (alloc_size) { ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); #ifdef CONFIG_FAIR_GROUP_SCHED root_task_group.se = (struct sched_entity **)ptr; ptr += nr_cpu_ids * sizeof(void **); root_task_group.cfs_rq = (struct cfs_rq **)ptr; ptr += nr_cpu_ids * sizeof(void **); #endif /* CONFIG_FAIR_GROUP_SCHED */ #ifdef CONFIG_RT_GROUP_SCHED root_task_group.rt_se = (struct sched_rt_entity **)ptr; ptr += nr_cpu_ids * sizeof(void **); root_task_group.rt_rq = (struct rt_rq **)ptr; ptr += nr_cpu_ids * sizeof(void **); #endif /* CONFIG_RT_GROUP_SCHED */ } #ifdef CONFIG_CPUMASK_OFFSTACK for_each_possible_cpu(i) { per_cpu(load_balance_mask, i) = (cpumask_var_t)kzalloc_node( cpumask_size(), GFP_KERNEL, cpu_to_node(i)); } #endif /* CONFIG_CPUMASK_OFFSTACK */ init_rt_bandwidth(&def_rt_bandwidth, global_rt_period(), global_rt_runtime()); init_dl_bandwidth(&def_dl_bandwidth, global_rt_period(), global_rt_runtime()); #ifdef CONFIG_SMP init_defrootdomain(); #endif #ifdef CONFIG_RT_GROUP_SCHED init_rt_bandwidth(&root_task_group.rt_bandwidth, global_rt_period(), global_rt_runtime()); #endif /* CONFIG_RT_GROUP_SCHED */ #ifdef CONFIG_CGROUP_SCHED list_add(&root_task_group.list, &task_groups); INIT_LIST_HEAD(&root_task_group.children); INIT_LIST_HEAD(&root_task_group.siblings); autogroup_init(&init_task); #endif /* CONFIG_CGROUP_SCHED */ for_each_possible_cpu(i) { struct rq *rq; rq = cpu_rq(i); raw_spin_lock_init(&rq->lock); rq->nr_running = 0; rq->calc_load_active = 0; rq->calc_load_update = jiffies + LOAD_FREQ; init_cfs_rq(&rq->cfs); init_rt_rq(&rq->rt); init_dl_rq(&rq->dl); #ifdef CONFIG_FAIR_GROUP_SCHED root_task_group.shares = ROOT_TASK_GROUP_LOAD; INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); /* * How much cpu bandwidth does root_task_group get? * * In case of task-groups formed thr' the cgroup filesystem, it * gets 100% of the cpu resources in the system. This overall * system cpu resource is divided among the tasks of * root_task_group and its child task-groups in a fair manner, * based on each entity's (task or task-group's) weight * (se->load.weight). * * In other words, if root_task_group has 10 tasks of weight * 1024) and two child groups A0 and A1 (of weight 1024 each), * then A0's share of the cpu resource is: * * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% * * 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 */ rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; #ifdef CONFIG_RT_GROUP_SCHED init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); #endif for (j = 0; j < CPU_LOAD_IDX_MAX; j++) rq->cpu_load[j] = 0; rq->last_load_update_tick = jiffies; #ifdef CONFIG_SMP rq->sd = NULL; rq->rd = NULL; rq->cpu_capacity = rq->cpu_capacity_orig = SCHED_CAPACITY_SCALE; rq->post_schedule = 0; rq->active_balance = 0; rq->next_balance = jiffies; rq->push_cpu = 0; rq->cpu = i; rq->online = 0; rq->idle_stamp = 0; rq->avg_idle = 2*sysctl_sched_migration_cost; rq->max_idle_balance_cost = sysctl_sched_migration_cost; INIT_LIST_HEAD(&rq->cfs_tasks); rq_attach_root(rq, &def_root_domain); #ifdef CONFIG_NO_HZ_COMMON rq->nohz_flags = 0; #endif #ifdef CONFIG_NO_HZ_FULL rq->last_sched_tick = 0; #endif #endif init_rq_hrtick(rq); atomic_set(&rq->nr_iowait, 0); } set_load_weight(&init_task); #ifdef CONFIG_PREEMPT_NOTIFIERS INIT_HLIST_HEAD(&init_task.preempt_notifiers); #endif /* * The boot idle thread does lazy MMU switching as well: */ atomic_inc(&init_mm.mm_count); enter_lazy_tlb(&init_mm, current); /* * During early bootup we pretend to be a normal task: */ current->sched_class = &fair_sched_class; /* * Make us the idle thread. Technically, schedule() should not be * called from this thread, however somewhere below it might be, * but because we are the idle thread, we just pick up running again * when this runqueue becomes "idle". */ init_idle(current, smp_processor_id()); calc_load_update = jiffies + LOAD_FREQ; #ifdef CONFIG_SMP zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); /* May be allocated at isolcpus cmdline parse time */ if (cpu_isolated_map == NULL) zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); idle_thread_set_boot_cpu(); set_cpu_rq_start_time(); #endif init_sched_fair_class(); scheduler_running = 1; } #ifdef CONFIG_DEBUG_ATOMIC_SLEEP static inline int preempt_count_equals(int preempt_offset) { int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); return (nested == preempt_offset); } void __might_sleep(const char *file, int line, int preempt_offset) { /* * Blocking primitives will set (and therefore destroy) current->state, * since we will exit with TASK_RUNNING make sure we enter with it, * otherwise we will destroy state. */ WARN_ONCE(current->state != TASK_RUNNING && current->task_state_change, "do not call blocking ops when !TASK_RUNNING; " "state=%lx set at [<%p>] %pS\n", current->state, (void *)current->task_state_change, (void *)current->task_state_change); ___might_sleep(file, line, preempt_offset); } EXPORT_SYMBOL(__might_sleep); 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() && !is_idle_task(current)) || system_state != SYSTEM_RUNNING || oops_in_progress) return; if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) return; prev_jiffy = jiffies; printk(KERN_ERR "BUG: sleeping function called from invalid context at %s:%d\n", file, line); printk(KERN_ERR "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", in_atomic(), irqs_disabled(), current->pid, current->comm); if (task_stack_end_corrupted(current)) printk(KERN_EMERG "Thread overran stack, or stack corrupted\n"); debug_show_held_locks(current); if (irqs_disabled()) print_irqtrace_events(current); #ifdef CONFIG_DEBUG_PREEMPT if (!preempt_count_equals(preempt_offset)) { pr_err("Preemption disabled at:"); print_ip_sym(current->preempt_disable_ip); pr_cont("\n"); } #endif dump_stack(); } EXPORT_SYMBOL(___might_sleep); #endif #ifdef CONFIG_MAGIC_SYSRQ static void normalize_task(struct rq *rq, struct task_struct *p) { const struct sched_class *prev_class = p->sched_class; struct sched_attr attr = { .sched_policy = SCHED_NORMAL, }; int old_prio = p->prio; int queued; queued = task_on_rq_queued(p); if (queued) dequeue_task(rq, p, 0); __setscheduler(rq, p, &attr, false); if (queued) { enqueue_task(rq, p, 0); resched_curr(rq); } check_class_changed(rq, p, prev_class, old_prio); } void normalize_rt_tasks(void) { struct task_struct *g, *p; unsigned long flags; struct rq *rq; read_lock(&tasklist_lock); for_each_process_thread(g, p) { /* * Only normalize user tasks: */ if (p->flags & PF_KTHREAD) continue; p->se.exec_start = 0; #ifdef CONFIG_SCHEDSTATS p->se.statistics.wait_start = 0; p->se.statistics.sleep_start = 0; p->se.statistics.block_start = 0; #endif if (!dl_task(p) && !rt_task(p)) { /* * Renice negative nice level userspace * tasks back to 0: */ if (task_nice(p) < 0) set_user_nice(p, 0); continue; } rq = task_rq_lock(p, &flags); normalize_task(rq, p); task_rq_unlock(rq, p, &flags); } read_unlock(&tasklist_lock); } #endif /* CONFIG_MAGIC_SYSRQ */ #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) /* * These functions are only useful for the IA64 MCA handling, or kdb. * * They can only be called when the whole system has been * stopped - every CPU needs to be quiescent, and no scheduling * activity can take place. Using them for anything else would * be a serious bug, and as a result, they aren't even visible * under any other configuration. */ /** * curr_task - return the current task for a given cpu. * @cpu: the processor in question. * * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! * * Return: The current task for @cpu. */ struct task_struct *curr_task(int cpu) { return cpu_curr(cpu); } #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ #ifdef CONFIG_IA64 /** * set_curr_task - set the current task for a given cpu. * @cpu: the processor in question. * @p: the task pointer to set. * * Description: This function must only be used when non-maskable interrupts * are serviced on a separate stack. It allows the architecture to switch the * notion of the current task on a cpu in a non-blocking manner. This function * must be called with all CPU's synchronized, and interrupts disabled, the * and caller must save the original value of the current task (see * curr_task() above) and restore that value before reenabling interrupts and * re-starting the system. * * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! */ void set_curr_task(int cpu, struct task_struct *p) { cpu_curr(cpu) = p; } #endif #ifdef CONFIG_CGROUP_SCHED /* task_group_lock serializes the addition/removal of task groups */ static DEFINE_SPINLOCK(task_group_lock); static void free_sched_group(struct task_group *tg) { free_fair_sched_group(tg); free_rt_sched_group(tg); autogroup_free(tg); kfree(tg); } /* allocate runqueue etc for a new task group */ struct task_group *sched_create_group(struct task_group *parent) { struct task_group *tg; tg = kzalloc(sizeof(*tg), GFP_KERNEL); if (!tg) return ERR_PTR(-ENOMEM); if (!alloc_fair_sched_group(tg, parent)) goto err; if (!alloc_rt_sched_group(tg, parent)) goto err; return tg; err: free_sched_group(tg); return ERR_PTR(-ENOMEM); } void sched_online_group(struct task_group *tg, struct task_group *parent) { unsigned long flags; spin_lock_irqsave(&task_group_lock, flags); list_add_rcu(&tg->list, &task_groups); WARN_ON(!parent); /* root should already exist */ tg->parent = parent; INIT_LIST_HEAD(&tg->children); list_add_rcu(&tg->siblings, &parent->children); spin_unlock_irqrestore(&task_group_lock, flags); } /* rcu callback to free various structures associated with a task group */ static void free_sched_group_rcu(struct rcu_head *rhp) { /* now it should be safe to free those cfs_rqs */ free_sched_group(container_of(rhp, struct task_group, rcu)); } /* Destroy runqueue etc associated with a task group */ void sched_destroy_group(struct task_group *tg) { /* wait for possible concurrent references to cfs_rqs complete */ call_rcu(&tg->rcu, free_sched_group_rcu); } void sched_offline_group(struct task_group *tg) { unsigned long flags; int i; /* end participation in shares distribution */ for_each_possible_cpu(i) unregister_fair_sched_group(tg, i); spin_lock_irqsave(&task_group_lock, flags); list_del_rcu(&tg->list); list_del_rcu(&tg->siblings); spin_unlock_irqrestore(&task_group_lock, flags); } /* change task's runqueue when it moves between groups. * The caller of this function should have put the task in its new group * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to * reflect its new group. */ void sched_move_task(struct task_struct *tsk) { struct task_group *tg; int queued, running; unsigned long flags; struct rq *rq; rq = task_rq_lock(tsk, &flags); running = task_current(rq, tsk); queued = task_on_rq_queued(tsk); if (queued) dequeue_task(rq, tsk, 0); if (unlikely(running)) put_prev_task(rq, tsk); /* * All callers are synchronized by task_rq_lock(); we do not use RCU * which is pointless here. Thus, we pass "true" to task_css_check() * to prevent lockdep warnings. */ tg = container_of(task_css_check(tsk, cpu_cgrp_id, true), struct task_group, css); tg = autogroup_task_group(tsk, tg); tsk->sched_task_group = tg; #ifdef CONFIG_FAIR_GROUP_SCHED if (tsk->sched_class->task_move_group) tsk->sched_class->task_move_group(tsk, queued); else #endif set_task_rq(tsk, task_cpu(tsk)); if (unlikely(running)) tsk->sched_class->set_curr_task(rq); if (queued) enqueue_task(rq, tsk, 0); task_rq_unlock(rq, tsk, &flags); } #endif /* CONFIG_CGROUP_SCHED */ #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; } static 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); } static 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; } static int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) { u64 rt_runtime, rt_period; rt_period = (u64)rt_period_us * NSEC_PER_USEC; rt_runtime = tg->rt_bandwidth.rt_runtime; return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); } static 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; } #endif /* CONFIG_RT_GROUP_SCHED */ #ifdef CONFIG_RT_GROUP_SCHED 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; } static 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, ret = 0; 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 ret; } #endif /* CONFIG_RT_GROUP_SCHED */ static int sched_dl_global_validate(void) { u64 runtime = global_rt_runtime(); u64 period = global_rt_period(); u64 new_bw = to_ratio(period, runtime); struct dl_bw *dl_b; int cpu, ret = 0; unsigned long flags; /* * Here we want to check the bandwidth not being set to some * value smaller than the currently allocated bandwidth in * any of the root_domains. * * FIXME: Cycling on all the CPUs is overdoing, but simpler than * cycling on root_domains... Discussion on different/better * solutions is welcome! */ for_each_possible_cpu(cpu) { rcu_read_lock_sched(); dl_b = dl_bw_of(cpu); raw_spin_lock_irqsave(&dl_b->lock, flags); if (new_bw < dl_b->total_bw) ret = -EBUSY; raw_spin_unlock_irqrestore(&dl_b->lock, flags); rcu_read_unlock_sched(); if (ret) break; } return ret; } static void sched_dl_do_global(void) { u64 new_bw = -1; struct dl_bw *dl_b; int cpu; unsigned long flags; def_dl_bandwidth.dl_period = global_rt_period(); def_dl_bandwidth.dl_runtime = global_rt_runtime(); if (global_rt_runtime() != RUNTIME_INF) new_bw = to_ratio(global_rt_period(), global_rt_runtime()); /* * FIXME: As above... */ for_each_possible_cpu(cpu) { rcu_read_lock_sched(); dl_b = dl_bw_of(cpu); raw_spin_lock_irqsave(&dl_b->lock, flags); dl_b->bw = new_bw; raw_spin_unlock_irqrestore(&dl_b->lock, flags); rcu_read_unlock_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 timeslice to default */ if (!ret && write) { sched_rr_timeslice = sched_rr_timeslice <= 0 ? RR_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice); } mutex_unlock(&mutex); return ret; } #ifdef CONFIG_CGROUP_SCHED static inline struct task_group *css_tg(struct cgroup_subsys_state *css) { return css ? container_of(css, struct task_group, css) : NULL; } static struct cgroup_subsys_state * cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) { struct task_group *parent = css_tg(parent_css); struct task_group *tg; if (!parent) { /* This is early initialization for the top cgroup */ return &root_task_group.css; } tg = sched_create_group(parent); if (IS_ERR(tg)) return ERR_PTR(-ENOMEM); return &tg->css; } static int cpu_cgroup_css_online(struct cgroup_subsys_state *css) { struct task_group *tg = css_tg(css); struct task_group *parent = css_tg(css->parent); if (parent) sched_online_group(tg, parent); return 0; } static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) { struct task_group *tg = css_tg(css); sched_destroy_group(tg); } static void cpu_cgroup_css_offline(struct cgroup_subsys_state *css) { struct task_group *tg = css_tg(css); sched_offline_group(tg); } static void cpu_cgroup_fork(struct task_struct *task) { sched_move_task(task); } static int cpu_cgroup_can_attach(struct cgroup_subsys_state *css, struct cgroup_taskset *tset) { struct task_struct *task; cgroup_taskset_for_each(task, tset) { #ifdef CONFIG_RT_GROUP_SCHED if (!sched_rt_can_attach(css_tg(css), task)) return -EINVAL; #else /* We don't support RT-tasks being in separate groups */ if (task->sched_class != &fair_sched_class) return -EINVAL; #endif } return 0; } static void cpu_cgroup_attach(struct cgroup_subsys_state *css, struct cgroup_taskset *tset) { struct task_struct *task; cgroup_taskset_for_each(task, tset) sched_move_task(task); } static void cpu_cgroup_exit(struct cgroup_subsys_state *css, struct cgroup_subsys_state *old_css, struct task_struct *task) { /* * cgroup_exit() is called in the copy_process() failure path. * Ignore this case since the task hasn't ran yet, this avoids * trying to poke a half freed task state from generic code. */ if (!(task->flags & PF_EXITING)) return; sched_move_task(task); } #ifdef CONFIG_FAIR_GROUP_SCHED static int cpu_shares_write_u64(struct cgroup_subsys_state *css, struct cftype *cftype, u64 shareval) { return sched_group_set_shares(css_tg(css), scale_load(shareval)); } static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css, struct cftype *cft) { struct task_group *tg = css_tg(css); 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, runtime_was_enabled; struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 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; /* * Prevent race between setting of cfs_rq->runtime_enabled and * unthrottle_offline_cfs_rqs(). */ get_online_cpus(); mutex_lock(&cfs_constraints_mutex); ret = __cfs_schedulable(tg, period, quota); if (ret) goto out_unlock; runtime_enabled = quota != RUNTIME_INF; runtime_was_enabled = cfs_b->quota != RUNTIME_INF; /* * If we need to toggle cfs_bandwidth_used, off->on must occur * before making related changes, and on->off must occur afterwards */ if (runtime_enabled && !runtime_was_enabled) cfs_bandwidth_usage_inc(); 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 */ __start_cfs_bandwidth(cfs_b, true); } raw_spin_unlock_irq(&cfs_b->lock); for_each_online_cpu(i) { struct cfs_rq *cfs_rq = tg->cfs_rq[i]; struct rq *rq = cfs_rq->rq; raw_spin_lock_irq(&rq->lock); cfs_rq->runtime_enabled = runtime_enabled; cfs_rq->runtime_remaining = 0; if (cfs_rq->throttled) unthrottle_cfs_rq(cfs_rq); raw_spin_unlock_irq(&rq->lock); } if (runtime_was_enabled && !runtime_enabled) cfs_bandwidth_usage_dec(); out_unlock: mutex_unlock(&cfs_constraints_mutex); put_online_cpus(); 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.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.quota == RUNTIME_INF) return -1; quota_us = tg->cfs_bandwidth.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.quota; 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.period); do_div(cfs_period_us, NSEC_PER_USEC); return cfs_period_us; } static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css, struct cftype *cft) { return tg_get_cfs_quota(css_tg(css)); } static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css, struct cftype *cftype, s64 cfs_quota_us) { return tg_set_cfs_quota(css_tg(css), cfs_quota_us); } static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css, struct cftype *cft) { return tg_get_cfs_period(css_tg(css)); } static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css, struct cftype *cftype, u64 cfs_period_us) { return tg_set_cfs_period(css_tg(css), 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; s64 quota = 0, parent_quota = -1; if (!tg->parent) { quota = RUNTIME_INF; } else { struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; quota = normalize_cfs_quota(tg, d); parent_quota = parent_b->hierarchical_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->hierarchical_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 seq_file *sf, void *v) { struct task_group *tg = css_tg(seq_css(sf)); struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; seq_printf(sf, "nr_periods %d\n", cfs_b->nr_periods); seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled); seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time); return 0; } #endif /* CONFIG_CFS_BANDWIDTH */ #endif /* CONFIG_FAIR_GROUP_SCHED */ #ifdef CONFIG_RT_GROUP_SCHED static int cpu_rt_runtime_write(struct cgroup_subsys_state *css, struct cftype *cft, s64 val) { return sched_group_set_rt_runtime(css_tg(css), val); } static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css, struct cftype *cft) { return sched_group_rt_runtime(css_tg(css)); } static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css, struct cftype *cftype, u64 rt_period_us) { return sched_group_set_rt_period(css_tg(css), rt_period_us); } static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css, struct cftype *cft) { return sched_group_rt_period(css_tg(css)); } #endif /* CONFIG_RT_GROUP_SCHED */ static struct cftype cpu_files[] = { #ifdef CONFIG_FAIR_GROUP_SCHED { .name = "shares", .read_u64 = cpu_shares_read_u64, .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", .seq_show = cpu_stats_show, }, #endif #ifdef CONFIG_RT_GROUP_SCHED { .name = "rt_runtime_us", .read_s64 = cpu_rt_runtime_read, .write_s64 = cpu_rt_runtime_write, }, { .name = "rt_period_us", .read_u64 = cpu_rt_period_read_uint, .write_u64 = cpu_rt_period_write_uint, }, #endif { } /* terminate */ }; struct cgroup_subsys cpu_cgrp_subsys = { .css_alloc = cpu_cgroup_css_alloc, .css_free = cpu_cgroup_css_free, .css_online = cpu_cgroup_css_online, .css_offline = cpu_cgroup_css_offline, .fork = cpu_cgroup_fork, .can_attach = cpu_cgroup_can_attach, .attach = cpu_cgroup_attach, .exit = cpu_cgroup_exit, .legacy_cftypes = cpu_files, .early_init = 1, }; #endif /* CONFIG_CGROUP_SCHED */ void dump_cpu_task(int cpu) { pr_info("Task dump for CPU %d:\n", cpu); sched_show_task(cpu_curr(cpu)); }