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- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * kernel/sched/core.c
- *
- * Core kernel scheduler code and related syscalls
- *
- * Copyright (C) 1991-2002 Linus Torvalds
- */
- #define CREATE_TRACE_POINTS
- #include <trace/events/sched.h>
- #undef CREATE_TRACE_POINTS
- #include "sched.h"
- #include <linux/nospec.h>
- #include <linux/kcov.h>
- #include <linux/scs.h>
- #include <asm/switch_to.h>
- #include <asm/tlb.h>
- #include "../workqueue_internal.h"
- #include "../../fs/io-wq.h"
- #include "../smpboot.h"
- #include "pelt.h"
- #include "smp.h"
- #include <trace/hooks/sched.h>
- #include <trace/hooks/dtask.h>
- /*
- * Export tracepoints that act as a bare tracehook (ie: have no trace event
- * associated with them) to allow external modules to probe them.
- */
- EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_cfs_tp);
- EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_rt_tp);
- EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_dl_tp);
- EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_irq_tp);
- EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_se_tp);
- EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_thermal_tp);
- EXPORT_TRACEPOINT_SYMBOL_GPL(sched_cpu_capacity_tp);
- EXPORT_TRACEPOINT_SYMBOL_GPL(sched_overutilized_tp);
- EXPORT_TRACEPOINT_SYMBOL_GPL(sched_util_est_cfs_tp);
- EXPORT_TRACEPOINT_SYMBOL_GPL(sched_util_est_se_tp);
- EXPORT_TRACEPOINT_SYMBOL_GPL(sched_update_nr_running_tp);
- EXPORT_TRACEPOINT_SYMBOL_GPL(sched_switch);
- EXPORT_TRACEPOINT_SYMBOL_GPL(sched_waking);
- #ifdef CONFIG_SCHEDSTATS
- EXPORT_TRACEPOINT_SYMBOL_GPL(sched_stat_sleep);
- EXPORT_TRACEPOINT_SYMBOL_GPL(sched_stat_wait);
- EXPORT_TRACEPOINT_SYMBOL_GPL(sched_stat_iowait);
- EXPORT_TRACEPOINT_SYMBOL_GPL(sched_stat_blocked);
- #endif
- DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
- EXPORT_SYMBOL_GPL(runqueues);
- #ifdef CONFIG_SCHED_DEBUG
- /*
- * Debugging: various feature bits
- *
- * If SCHED_DEBUG is disabled, each compilation unit has its own copy of
- * sysctl_sched_features, defined in sched.h, to allow constants propagation
- * at compile time and compiler optimization based on features default.
- */
- #define SCHED_FEAT(name, enabled) \
- (1UL << __SCHED_FEAT_##name) * enabled |
- const_debug unsigned int sysctl_sched_features =
- #include "features.h"
- 0;
- EXPORT_SYMBOL_GPL(sysctl_sched_features);
- #undef SCHED_FEAT
- #endif
- /*
- * 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 measure -rt task CPU usage in us.
- * default: 1s
- */
- unsigned int sysctl_sched_rt_period = 1000000;
- __read_mostly int scheduler_running;
- /*
- * part of the period that we allow rt tasks to run in us.
- * default: 0.95s
- */
- int sysctl_sched_rt_runtime = 950000;
- /*
- * Serialization rules:
- *
- * Lock order:
- *
- * p->pi_lock
- * rq->lock
- * hrtimer_cpu_base->lock (hrtimer_start() for bandwidth controls)
- *
- * rq1->lock
- * rq2->lock where: rq1 < rq2
- *
- * Regular state:
- *
- * Normal scheduling state is serialized by rq->lock. __schedule() takes the
- * local CPU's rq->lock, it optionally removes the task from the runqueue and
- * always looks at the local rq data structures to find the most elegible task
- * to run next.
- *
- * Task enqueue is also under rq->lock, possibly taken from another CPU.
- * Wakeups from another LLC domain might use an IPI to transfer the enqueue to
- * the local CPU to avoid bouncing the runqueue state around [ see
- * ttwu_queue_wakelist() ]
- *
- * Task wakeup, specifically wakeups that involve migration, are horribly
- * complicated to avoid having to take two rq->locks.
- *
- * Special state:
- *
- * System-calls and anything external will use task_rq_lock() which acquires
- * both p->pi_lock and rq->lock. As a consequence the state they change is
- * stable while holding either lock:
- *
- * - sched_setaffinity()/
- * set_cpus_allowed_ptr(): p->cpus_ptr, p->nr_cpus_allowed
- * - set_user_nice(): p->se.load, p->*prio
- * - __sched_setscheduler(): p->sched_class, p->policy, p->*prio,
- * p->se.load, p->rt_priority,
- * p->dl.dl_{runtime, deadline, period, flags, bw, density}
- * - sched_setnuma(): p->numa_preferred_nid
- * - sched_move_task()/
- * cpu_cgroup_fork(): p->sched_task_group
- * - uclamp_update_active() p->uclamp*
- *
- * p->state <- TASK_*:
- *
- * is changed locklessly using set_current_state(), __set_current_state() or
- * set_special_state(), see their respective comments, or by
- * try_to_wake_up(). This latter uses p->pi_lock to serialize against
- * concurrent self.
- *
- * p->on_rq <- { 0, 1 = TASK_ON_RQ_QUEUED, 2 = TASK_ON_RQ_MIGRATING }:
- *
- * is set by activate_task() and cleared by deactivate_task(), under
- * rq->lock. Non-zero indicates the task is runnable, the special
- * ON_RQ_MIGRATING state is used for migration without holding both
- * rq->locks. It indicates task_cpu() is not stable, see task_rq_lock().
- *
- * p->on_cpu <- { 0, 1 }:
- *
- * is set by prepare_task() and cleared by finish_task() such that it will be
- * set before p is scheduled-in and cleared after p is scheduled-out, both
- * under rq->lock. Non-zero indicates the task is running on its CPU.
- *
- * [ The astute reader will observe that it is possible for two tasks on one
- * CPU to have ->on_cpu = 1 at the same time. ]
- *
- * task_cpu(p): is changed by set_task_cpu(), the rules are:
- *
- * - Don't call set_task_cpu() on a blocked task:
- *
- * We don't care what CPU we're not running on, this simplifies hotplug,
- * the CPU assignment of blocked tasks isn't required to be valid.
- *
- * - for try_to_wake_up(), called under p->pi_lock:
- *
- * This allows try_to_wake_up() to only take one rq->lock, see its comment.
- *
- * - for migration called under rq->lock:
- * [ see task_on_rq_migrating() in task_rq_lock() ]
- *
- * o move_queued_task()
- * o detach_task()
- *
- * - for migration called under double_rq_lock():
- *
- * o __migrate_swap_task()
- * o push_rt_task() / pull_rt_task()
- * o push_dl_task() / pull_dl_task()
- * o dl_task_offline_migration()
- *
- */
- /*
- * __task_rq_lock - lock the rq @p resides on.
- */
- struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
- __acquires(rq->lock)
- {
- struct rq *rq;
- lockdep_assert_held(&p->pi_lock);
- for (;;) {
- rq = task_rq(p);
- raw_spin_lock(&rq->lock);
- if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) {
- rq_pin_lock(rq, rf);
- return rq;
- }
- raw_spin_unlock(&rq->lock);
- while (unlikely(task_on_rq_migrating(p)))
- cpu_relax();
- }
- }
- EXPORT_SYMBOL_GPL(__task_rq_lock);
- /*
- * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
- */
- struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
- __acquires(p->pi_lock)
- __acquires(rq->lock)
- {
- struct rq *rq;
- for (;;) {
- raw_spin_lock_irqsave(&p->pi_lock, rf->flags);
- rq = task_rq(p);
- raw_spin_lock(&rq->lock);
- /*
- * move_queued_task() task_rq_lock()
- *
- * ACQUIRE (rq->lock)
- * [S] ->on_rq = MIGRATING [L] rq = task_rq()
- * WMB (__set_task_cpu()) ACQUIRE (rq->lock);
- * [S] ->cpu = new_cpu [L] task_rq()
- * [L] ->on_rq
- * RELEASE (rq->lock)
- *
- * If we observe the old CPU in task_rq_lock(), the acquire of
- * the old rq->lock will fully serialize against the stores.
- *
- * If we observe the new CPU in task_rq_lock(), the address
- * dependency headed by '[L] rq = task_rq()' and the acquire
- * will pair with the WMB to ensure we then also see migrating.
- */
- if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) {
- rq_pin_lock(rq, rf);
- return rq;
- }
- raw_spin_unlock(&rq->lock);
- raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
- while (unlikely(task_on_rq_migrating(p)))
- cpu_relax();
- }
- }
- EXPORT_SYMBOL_GPL(task_rq_lock);
- /*
- * RQ-clock updating methods:
- */
- 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...
- */
- s64 __maybe_unused steal = 0, irq_delta = 0;
- #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;
- #ifdef CONFIG_HAVE_SCHED_AVG_IRQ
- if ((irq_delta + steal) && sched_feat(NONTASK_CAPACITY))
- update_irq_load_avg(rq, irq_delta + steal);
- #endif
- update_rq_clock_pelt(rq, delta);
- }
- void update_rq_clock(struct rq *rq)
- {
- s64 delta;
- lockdep_assert_held(&rq->lock);
- if (rq->clock_update_flags & RQCF_ACT_SKIP)
- return;
- #ifdef CONFIG_SCHED_DEBUG
- if (sched_feat(WARN_DOUBLE_CLOCK))
- SCHED_WARN_ON(rq->clock_update_flags & RQCF_UPDATED);
- rq->clock_update_flags |= RQCF_UPDATED;
- #endif
- delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
- if (delta < 0)
- return;
- rq->clock += delta;
- update_rq_clock_task(rq, delta);
- }
- EXPORT_SYMBOL_GPL(update_rq_clock);
- static inline void
- rq_csd_init(struct rq *rq, struct __call_single_data *csd, smp_call_func_t func)
- {
- csd->flags = 0;
- csd->func = func;
- csd->info = 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);
- struct rq_flags rf;
- WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
- rq_lock(rq, &rf);
- update_rq_clock(rq);
- rq->curr->sched_class->task_tick(rq, rq->curr, 1);
- rq_unlock(rq, &rf);
- return HRTIMER_NORESTART;
- }
- #ifdef CONFIG_SMP
- static void __hrtick_restart(struct rq *rq)
- {
- struct hrtimer *timer = &rq->hrtick_timer;
- ktime_t time = rq->hrtick_time;
- hrtimer_start(timer, time, HRTIMER_MODE_ABS_PINNED_HARD);
- }
- /*
- * called from hardirq (IPI) context
- */
- static void __hrtick_start(void *arg)
- {
- struct rq *rq = arg;
- struct rq_flags rf;
- rq_lock(rq, &rf);
- __hrtick_restart(rq);
- rq_unlock(rq, &rf);
- }
- /*
- * 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;
- 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);
- rq->hrtick_time = ktime_add_ns(timer->base->get_time(), delta);
- if (rq == this_rq())
- __hrtick_restart(rq);
- else
- smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd);
- }
- #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(&rq->hrtick_timer, ns_to_ktime(delay),
- HRTIMER_MODE_REL_PINNED_HARD);
- }
- #endif /* CONFIG_SMP */
- static void hrtick_rq_init(struct rq *rq)
- {
- #ifdef CONFIG_SMP
- rq_csd_init(rq, &rq->hrtick_csd, __hrtick_start);
- #endif
- hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
- rq->hrtick_timer.function = hrtick;
- }
- #else /* CONFIG_SCHED_HRTICK */
- static inline void hrtick_clear(struct rq *rq)
- {
- }
- static inline void hrtick_rq_init(struct rq *rq)
- {
- }
- #endif /* CONFIG_SCHED_HRTICK */
- /*
- * cmpxchg based fetch_or, macro so it works for different integer types
- */
- #define fetch_or(ptr, mask) \
- ({ \
- typeof(ptr) _ptr = (ptr); \
- typeof(mask) _mask = (mask); \
- typeof(*_ptr) _old, _val = *_ptr; \
- \
- for (;;) { \
- _old = cmpxchg(_ptr, _val, _val | _mask); \
- 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 = READ_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
- static bool __wake_q_add(struct wake_q_head *head, struct task_struct *task)
- {
- struct wake_q_node *node = &task->wake_q;
- /*
- * Atomically grab the task, if ->wake_q is !nil already it means
- * its already queued (either by us or someone else) and will get the
- * wakeup due to that.
- *
- * In order to ensure that a pending wakeup will observe our pending
- * state, even in the failed case, an explicit smp_mb() must be used.
- */
- smp_mb__before_atomic();
- if (unlikely(cmpxchg_relaxed(&node->next, NULL, WAKE_Q_TAIL)))
- return false;
- /*
- * The head is context local, there can be no concurrency.
- */
- *head->lastp = node;
- head->lastp = &node->next;
- head->count++;
- return true;
- }
- /**
- * wake_q_add() - queue a wakeup for 'later' waking.
- * @head: the wake_q_head to add @task to
- * @task: the task to queue for 'later' wakeup
- *
- * Queue a task for later wakeup, most likely by the wake_up_q() call in the
- * same context, _HOWEVER_ this is not guaranteed, the wakeup can come
- * instantly.
- *
- * This function must be used as-if it were wake_up_process(); IOW the task
- * must be ready to be woken at this location.
- */
- void wake_q_add(struct wake_q_head *head, struct task_struct *task)
- {
- if (__wake_q_add(head, task))
- get_task_struct(task);
- }
- /**
- * wake_q_add_safe() - safely queue a wakeup for 'later' waking.
- * @head: the wake_q_head to add @task to
- * @task: the task to queue for 'later' wakeup
- *
- * Queue a task for later wakeup, most likely by the wake_up_q() call in the
- * same context, _HOWEVER_ this is not guaranteed, the wakeup can come
- * instantly.
- *
- * This function must be used as-if it were wake_up_process(); IOW the task
- * must be ready to be woken at this location.
- *
- * This function is essentially a task-safe equivalent to wake_q_add(). Callers
- * that already hold reference to @task can call the 'safe' version and trust
- * wake_q to do the right thing depending whether or not the @task is already
- * queued for wakeup.
- */
- void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task)
- {
- if (!__wake_q_add(head, task))
- put_task_struct(task);
- }
- void wake_up_q(struct wake_q_head *head)
- {
- struct wake_q_node *node = head->first;
- while (node != WAKE_Q_TAIL) {
- struct task_struct *task;
- task = container_of(node, struct task_struct, wake_q);
- BUG_ON(!task);
- /* Task can safely be re-inserted now: */
- node = node->next;
- task->wake_q.next = NULL;
- task->wake_q_count = head->count;
- /*
- * wake_up_process() executes a full barrier, which pairs with
- * the queueing in wake_q_add() so as not to miss wakeups.
- */
- wake_up_process(task);
- task->wake_q_count = 0;
- put_task_struct(task);
- }
- }
- /*
- * 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);
- }
- EXPORT_SYMBOL_GPL(resched_curr);
- 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(void)
- {
- int i, cpu = smp_processor_id(), default_cpu = -1;
- struct sched_domain *sd;
- if (housekeeping_cpu(cpu, HK_FLAG_TIMER) && cpu_active(cpu)) {
- if (!idle_cpu(cpu))
- return cpu;
- default_cpu = cpu;
- }
- rcu_read_lock();
- for_each_domain(cpu, sd) {
- for_each_cpu_and(i, sched_domain_span(sd),
- housekeeping_cpumask(HK_FLAG_TIMER)) {
- if (cpu == i)
- continue;
- if (!idle_cpu(i)) {
- cpu = i;
- goto unlock;
- }
- }
- }
- if (default_cpu == -1) {
- for_each_cpu_and(i, cpu_active_mask,
- housekeeping_cpumask(HK_FLAG_TIMER)) {
- if (cpu == i)
- continue;
- if (!idle_cpu(i)) {
- cpu = i;
- goto unlock;
- }
- }
- /* no active, not-idle, housekpeeing CPU found. */
- default_cpu = cpumask_any(cpu_active_mask);
- if (unlikely(default_cpu >= nr_cpu_ids))
- goto unlock;
- }
- cpu = default_cpu;
- 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 (cpu_is_offline(cpu))
- return true; /* Don't try to wake offline CPUs. */
- 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;
- }
- /*
- * Wake up the specified CPU. If the CPU is going offline, it is the
- * caller's responsibility to deal with the lost wakeup, for example,
- * by hooking into the CPU_DEAD notifier like timers and hrtimers do.
- */
- void wake_up_nohz_cpu(int cpu)
- {
- if (!wake_up_full_nohz_cpu(cpu))
- wake_up_idle_cpu(cpu);
- }
- static void nohz_csd_func(void *info)
- {
- struct rq *rq = info;
- int cpu = cpu_of(rq);
- unsigned int flags;
- /*
- * Release the rq::nohz_csd.
- */
- flags = atomic_fetch_andnot(NOHZ_KICK_MASK, nohz_flags(cpu));
- WARN_ON(!(flags & NOHZ_KICK_MASK));
- rq->idle_balance = idle_cpu(cpu);
- if (rq->idle_balance && !need_resched()) {
- rq->nohz_idle_balance = flags;
- raise_softirq_irqoff(SCHED_SOFTIRQ);
- }
- }
- #endif /* CONFIG_NO_HZ_COMMON */
- #ifdef CONFIG_NO_HZ_FULL
- bool sched_can_stop_tick(struct rq *rq)
- {
- int fifo_nr_running;
- /* Deadline tasks, even if single, need the tick */
- if (rq->dl.dl_nr_running)
- return false;
- /*
- * If there are more than one RR tasks, we need the tick to effect the
- * actual RR behaviour.
- */
- if (rq->rt.rr_nr_running) {
- if (rq->rt.rr_nr_running == 1)
- return true;
- else
- return false;
- }
- /*
- * If there's no RR tasks, but FIFO tasks, we can skip the tick, no
- * forced preemption between FIFO tasks.
- */
- fifo_nr_running = rq->rt.rt_nr_running - rq->rt.rr_nr_running;
- if (fifo_nr_running)
- return true;
- /*
- * If there are no DL,RR/FIFO tasks, there must only be CFS tasks left;
- * if there's more than one we need the tick for involuntary
- * preemption.
- */
- if (rq->nr_running > 1)
- return false;
- return true;
- }
- #endif /* CONFIG_NO_HZ_FULL */
- #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, bool update_load)
- {
- int prio = p->static_prio - MAX_RT_PRIO;
- struct load_weight *load = &p->se.load;
- /*
- * SCHED_IDLE tasks get minimal weight:
- */
- if (task_has_idle_policy(p)) {
- load->weight = scale_load(WEIGHT_IDLEPRIO);
- load->inv_weight = WMULT_IDLEPRIO;
- return;
- }
- /*
- * SCHED_OTHER tasks have to update their load when changing their
- * weight
- */
- if (update_load && p->sched_class == &fair_sched_class) {
- reweight_task(p, prio);
- } else {
- load->weight = scale_load(sched_prio_to_weight[prio]);
- load->inv_weight = sched_prio_to_wmult[prio];
- }
- }
- #ifdef CONFIG_UCLAMP_TASK
- /*
- * Serializes updates of utilization clamp values
- *
- * The (slow-path) user-space triggers utilization clamp value updates which
- * can require updates on (fast-path) scheduler's data structures used to
- * support enqueue/dequeue operations.
- * While the per-CPU rq lock protects fast-path update operations, user-space
- * requests are serialized using a mutex to reduce the risk of conflicting
- * updates or API abuses.
- */
- static DEFINE_MUTEX(uclamp_mutex);
- /* Max allowed minimum utilization */
- unsigned int sysctl_sched_uclamp_util_min = SCHED_CAPACITY_SCALE;
- /* Max allowed maximum utilization */
- unsigned int sysctl_sched_uclamp_util_max = SCHED_CAPACITY_SCALE;
- /*
- * By default RT tasks run at the maximum performance point/capacity of the
- * system. Uclamp enforces this by always setting UCLAMP_MIN of RT tasks to
- * SCHED_CAPACITY_SCALE.
- *
- * This knob allows admins to change the default behavior when uclamp is being
- * used. In battery powered devices, particularly, running at the maximum
- * capacity and frequency will increase energy consumption and shorten the
- * battery life.
- *
- * This knob only affects RT tasks that their uclamp_se->user_defined == false.
- *
- * This knob will not override the system default sched_util_clamp_min defined
- * above.
- */
- unsigned int sysctl_sched_uclamp_util_min_rt_default = SCHED_CAPACITY_SCALE;
- /* All clamps are required to be less or equal than these values */
- static struct uclamp_se uclamp_default[UCLAMP_CNT];
- /*
- * This static key is used to reduce the uclamp overhead in the fast path. It
- * primarily disables the call to uclamp_rq_{inc, dec}() in
- * enqueue/dequeue_task().
- *
- * This allows users to continue to enable uclamp in their kernel config with
- * minimum uclamp overhead in the fast path.
- *
- * As soon as userspace modifies any of the uclamp knobs, the static key is
- * enabled, since we have an actual users that make use of uclamp
- * functionality.
- *
- * The knobs that would enable this static key are:
- *
- * * A task modifying its uclamp value with sched_setattr().
- * * An admin modifying the sysctl_sched_uclamp_{min, max} via procfs.
- * * An admin modifying the cgroup cpu.uclamp.{min, max}
- */
- DEFINE_STATIC_KEY_FALSE(sched_uclamp_used);
- EXPORT_SYMBOL_GPL(sched_uclamp_used);
- /* Integer rounded range for each bucket */
- #define UCLAMP_BUCKET_DELTA DIV_ROUND_CLOSEST(SCHED_CAPACITY_SCALE, UCLAMP_BUCKETS)
- #define for_each_clamp_id(clamp_id) \
- for ((clamp_id) = 0; (clamp_id) < UCLAMP_CNT; (clamp_id)++)
- static inline unsigned int uclamp_bucket_id(unsigned int clamp_value)
- {
- return min_t(unsigned int, clamp_value / UCLAMP_BUCKET_DELTA, UCLAMP_BUCKETS - 1);
- }
- static inline unsigned int uclamp_none(enum uclamp_id clamp_id)
- {
- if (clamp_id == UCLAMP_MIN)
- return 0;
- return SCHED_CAPACITY_SCALE;
- }
- static inline void uclamp_se_set(struct uclamp_se *uc_se,
- unsigned int value, bool user_defined)
- {
- uc_se->value = value;
- uc_se->bucket_id = uclamp_bucket_id(value);
- uc_se->user_defined = user_defined;
- }
- static inline unsigned int
- uclamp_idle_value(struct rq *rq, enum uclamp_id clamp_id,
- unsigned int clamp_value)
- {
- /*
- * Avoid blocked utilization pushing up the frequency when we go
- * idle (which drops the max-clamp) by retaining the last known
- * max-clamp.
- */
- if (clamp_id == UCLAMP_MAX) {
- rq->uclamp_flags |= UCLAMP_FLAG_IDLE;
- return clamp_value;
- }
- return uclamp_none(UCLAMP_MIN);
- }
- static inline void uclamp_idle_reset(struct rq *rq, enum uclamp_id clamp_id,
- unsigned int clamp_value)
- {
- /* Reset max-clamp retention only on idle exit */
- if (!(rq->uclamp_flags & UCLAMP_FLAG_IDLE))
- return;
- WRITE_ONCE(rq->uclamp[clamp_id].value, clamp_value);
- }
- static inline
- unsigned int uclamp_rq_max_value(struct rq *rq, enum uclamp_id clamp_id,
- unsigned int clamp_value)
- {
- struct uclamp_bucket *bucket = rq->uclamp[clamp_id].bucket;
- int bucket_id = UCLAMP_BUCKETS - 1;
- /*
- * Since both min and max clamps are max aggregated, find the
- * top most bucket with tasks in.
- */
- for ( ; bucket_id >= 0; bucket_id--) {
- if (!bucket[bucket_id].tasks)
- continue;
- return bucket[bucket_id].value;
- }
- /* No tasks -- default clamp values */
- return uclamp_idle_value(rq, clamp_id, clamp_value);
- }
- static void __uclamp_update_util_min_rt_default(struct task_struct *p)
- {
- unsigned int default_util_min;
- struct uclamp_se *uc_se;
- lockdep_assert_held(&p->pi_lock);
- uc_se = &p->uclamp_req[UCLAMP_MIN];
- /* Only sync if user didn't override the default */
- if (uc_se->user_defined)
- return;
- default_util_min = sysctl_sched_uclamp_util_min_rt_default;
- uclamp_se_set(uc_se, default_util_min, false);
- }
- static void uclamp_update_util_min_rt_default(struct task_struct *p)
- {
- struct rq_flags rf;
- struct rq *rq;
- if (!rt_task(p))
- return;
- /* Protect updates to p->uclamp_* */
- rq = task_rq_lock(p, &rf);
- __uclamp_update_util_min_rt_default(p);
- task_rq_unlock(rq, p, &rf);
- }
- static void uclamp_sync_util_min_rt_default(void)
- {
- struct task_struct *g, *p;
- /*
- * copy_process() sysctl_uclamp
- * uclamp_min_rt = X;
- * write_lock(&tasklist_lock) read_lock(&tasklist_lock)
- * // link thread smp_mb__after_spinlock()
- * write_unlock(&tasklist_lock) read_unlock(&tasklist_lock);
- * sched_post_fork() for_each_process_thread()
- * __uclamp_sync_rt() __uclamp_sync_rt()
- *
- * Ensures that either sched_post_fork() will observe the new
- * uclamp_min_rt or for_each_process_thread() will observe the new
- * task.
- */
- read_lock(&tasklist_lock);
- smp_mb__after_spinlock();
- read_unlock(&tasklist_lock);
- rcu_read_lock();
- for_each_process_thread(g, p)
- uclamp_update_util_min_rt_default(p);
- rcu_read_unlock();
- }
- static inline struct uclamp_se
- uclamp_tg_restrict(struct task_struct *p, enum uclamp_id clamp_id)
- {
- /* Copy by value as we could modify it */
- struct uclamp_se uc_req = p->uclamp_req[clamp_id];
- #ifdef CONFIG_UCLAMP_TASK_GROUP
- unsigned int tg_min, tg_max, value;
- /*
- * Tasks in autogroups or root task group will be
- * restricted by system defaults.
- */
- if (task_group_is_autogroup(task_group(p)))
- return uc_req;
- if (task_group(p) == &root_task_group)
- return uc_req;
- tg_min = task_group(p)->uclamp[UCLAMP_MIN].value;
- tg_max = task_group(p)->uclamp[UCLAMP_MAX].value;
- value = uc_req.value;
- value = clamp(value, tg_min, tg_max);
- uclamp_se_set(&uc_req, value, false);
- #endif
- return uc_req;
- }
- /*
- * The effective clamp bucket index of a task depends on, by increasing
- * priority:
- * - the task specific clamp value, when explicitly requested from userspace
- * - the task group effective clamp value, for tasks not either in the root
- * group or in an autogroup
- * - the system default clamp value, defined by the sysadmin
- */
- static inline struct uclamp_se
- uclamp_eff_get(struct task_struct *p, enum uclamp_id clamp_id)
- {
- struct uclamp_se uc_req = uclamp_tg_restrict(p, clamp_id);
- struct uclamp_se uc_max = uclamp_default[clamp_id];
- struct uclamp_se uc_eff;
- int ret = 0;
- trace_android_rvh_uclamp_eff_get(p, clamp_id, &uc_max, &uc_eff, &ret);
- if (ret)
- return uc_eff;
- /* System default restrictions always apply */
- if (unlikely(uc_req.value > uc_max.value))
- return uc_max;
- return uc_req;
- }
- unsigned long uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id)
- {
- struct uclamp_se uc_eff;
- /* Task currently refcounted: use back-annotated (effective) value */
- if (p->uclamp[clamp_id].active)
- return (unsigned long)p->uclamp[clamp_id].value;
- uc_eff = uclamp_eff_get(p, clamp_id);
- return (unsigned long)uc_eff.value;
- }
- EXPORT_SYMBOL_GPL(uclamp_eff_value);
- /*
- * When a task is enqueued on a rq, the clamp bucket currently defined by the
- * task's uclamp::bucket_id is refcounted on that rq. This also immediately
- * updates the rq's clamp value if required.
- *
- * Tasks can have a task-specific value requested from user-space, track
- * within each bucket the maximum value for tasks refcounted in it.
- * This "local max aggregation" allows to track the exact "requested" value
- * for each bucket when all its RUNNABLE tasks require the same clamp.
- */
- static inline void uclamp_rq_inc_id(struct rq *rq, struct task_struct *p,
- enum uclamp_id clamp_id)
- {
- struct uclamp_rq *uc_rq = &rq->uclamp[clamp_id];
- struct uclamp_se *uc_se = &p->uclamp[clamp_id];
- struct uclamp_bucket *bucket;
- lockdep_assert_held(&rq->lock);
- /* Update task effective clamp */
- p->uclamp[clamp_id] = uclamp_eff_get(p, clamp_id);
- bucket = &uc_rq->bucket[uc_se->bucket_id];
- bucket->tasks++;
- uc_se->active = true;
- uclamp_idle_reset(rq, clamp_id, uc_se->value);
- /*
- * Local max aggregation: rq buckets always track the max
- * "requested" clamp value of its RUNNABLE tasks.
- */
- if (bucket->tasks == 1 || uc_se->value > bucket->value)
- bucket->value = uc_se->value;
- if (uc_se->value > READ_ONCE(uc_rq->value))
- WRITE_ONCE(uc_rq->value, uc_se->value);
- }
- /*
- * When a task is dequeued from a rq, the clamp bucket refcounted by the task
- * is released. If this is the last task reference counting the rq's max
- * active clamp value, then the rq's clamp value is updated.
- *
- * Both refcounted tasks and rq's cached clamp values are expected to be
- * always valid. If it's detected they are not, as defensive programming,
- * enforce the expected state and warn.
- */
- static inline void uclamp_rq_dec_id(struct rq *rq, struct task_struct *p,
- enum uclamp_id clamp_id)
- {
- struct uclamp_rq *uc_rq = &rq->uclamp[clamp_id];
- struct uclamp_se *uc_se = &p->uclamp[clamp_id];
- struct uclamp_bucket *bucket;
- unsigned int bkt_clamp;
- unsigned int rq_clamp;
- lockdep_assert_held(&rq->lock);
- /*
- * If sched_uclamp_used was enabled after task @p was enqueued,
- * we could end up with unbalanced call to uclamp_rq_dec_id().
- *
- * In this case the uc_se->active flag should be false since no uclamp
- * accounting was performed at enqueue time and we can just return
- * here.
- *
- * Need to be careful of the following enqeueue/dequeue ordering
- * problem too
- *
- * enqueue(taskA)
- * // sched_uclamp_used gets enabled
- * enqueue(taskB)
- * dequeue(taskA)
- * // Must not decrement bukcet->tasks here
- * dequeue(taskB)
- *
- * where we could end up with stale data in uc_se and
- * bucket[uc_se->bucket_id].
- *
- * The following check here eliminates the possibility of such race.
- */
- if (unlikely(!uc_se->active))
- return;
- bucket = &uc_rq->bucket[uc_se->bucket_id];
- SCHED_WARN_ON(!bucket->tasks);
- if (likely(bucket->tasks))
- bucket->tasks--;
- uc_se->active = false;
- /*
- * Keep "local max aggregation" simple and accept to (possibly)
- * overboost some RUNNABLE tasks in the same bucket.
- * The rq clamp bucket value is reset to its base value whenever
- * there are no more RUNNABLE tasks refcounting it.
- */
- if (likely(bucket->tasks))
- return;
- rq_clamp = READ_ONCE(uc_rq->value);
- /*
- * Defensive programming: this should never happen. If it happens,
- * e.g. due to future modification, warn and fixup the expected value.
- */
- SCHED_WARN_ON(bucket->value > rq_clamp);
- if (bucket->value >= rq_clamp) {
- bkt_clamp = uclamp_rq_max_value(rq, clamp_id, uc_se->value);
- WRITE_ONCE(uc_rq->value, bkt_clamp);
- }
- }
- static inline void uclamp_rq_inc(struct rq *rq, struct task_struct *p)
- {
- enum uclamp_id clamp_id;
- /*
- * Avoid any overhead until uclamp is actually used by the userspace.
- *
- * The condition is constructed such that a NOP is generated when
- * sched_uclamp_used is disabled.
- */
- if (!static_branch_unlikely(&sched_uclamp_used))
- return;
- if (unlikely(!p->sched_class->uclamp_enabled))
- return;
- for_each_clamp_id(clamp_id)
- uclamp_rq_inc_id(rq, p, clamp_id);
- /* Reset clamp idle holding when there is one RUNNABLE task */
- if (rq->uclamp_flags & UCLAMP_FLAG_IDLE)
- rq->uclamp_flags &= ~UCLAMP_FLAG_IDLE;
- }
- static inline void uclamp_rq_dec(struct rq *rq, struct task_struct *p)
- {
- enum uclamp_id clamp_id;
- /*
- * Avoid any overhead until uclamp is actually used by the userspace.
- *
- * The condition is constructed such that a NOP is generated when
- * sched_uclamp_used is disabled.
- */
- if (!static_branch_unlikely(&sched_uclamp_used))
- return;
- if (unlikely(!p->sched_class->uclamp_enabled))
- return;
- for_each_clamp_id(clamp_id)
- uclamp_rq_dec_id(rq, p, clamp_id);
- }
- static inline void uclamp_rq_reinc_id(struct rq *rq, struct task_struct *p,
- enum uclamp_id clamp_id)
- {
- if (!p->uclamp[clamp_id].active)
- return;
- uclamp_rq_dec_id(rq, p, clamp_id);
- uclamp_rq_inc_id(rq, p, clamp_id);
- /*
- * Make sure to clear the idle flag if we've transiently reached 0
- * active tasks on rq.
- */
- if (clamp_id == UCLAMP_MAX && (rq->uclamp_flags & UCLAMP_FLAG_IDLE))
- rq->uclamp_flags &= ~UCLAMP_FLAG_IDLE;
- }
- static inline void
- uclamp_update_active(struct task_struct *p)
- {
- enum uclamp_id clamp_id;
- struct rq_flags rf;
- struct rq *rq;
- /*
- * Lock the task and the rq where the task is (or was) queued.
- *
- * We might lock the (previous) rq of a !RUNNABLE task, but that's the
- * price to pay to safely serialize util_{min,max} updates with
- * enqueues, dequeues and migration operations.
- * This is the same locking schema used by __set_cpus_allowed_ptr().
- */
- rq = task_rq_lock(p, &rf);
- /*
- * Setting the clamp bucket is serialized by task_rq_lock().
- * If the task is not yet RUNNABLE and its task_struct is not
- * affecting a valid clamp bucket, the next time it's enqueued,
- * it will already see the updated clamp bucket value.
- */
- for_each_clamp_id(clamp_id)
- uclamp_rq_reinc_id(rq, p, clamp_id);
- task_rq_unlock(rq, p, &rf);
- }
- #ifdef CONFIG_UCLAMP_TASK_GROUP
- static inline void
- uclamp_update_active_tasks(struct cgroup_subsys_state *css)
- {
- struct css_task_iter it;
- struct task_struct *p;
- css_task_iter_start(css, 0, &it);
- while ((p = css_task_iter_next(&it)))
- uclamp_update_active(p);
- css_task_iter_end(&it);
- }
- static void cpu_util_update_eff(struct cgroup_subsys_state *css);
- static void uclamp_update_root_tg(void)
- {
- struct task_group *tg = &root_task_group;
- uclamp_se_set(&tg->uclamp_req[UCLAMP_MIN],
- sysctl_sched_uclamp_util_min, false);
- uclamp_se_set(&tg->uclamp_req[UCLAMP_MAX],
- sysctl_sched_uclamp_util_max, false);
- rcu_read_lock();
- cpu_util_update_eff(&root_task_group.css);
- rcu_read_unlock();
- }
- #else
- static void uclamp_update_root_tg(void) { }
- #endif
- int sysctl_sched_uclamp_handler(struct ctl_table *table, int write,
- void *buffer, size_t *lenp, loff_t *ppos)
- {
- bool update_root_tg = false;
- int old_min, old_max, old_min_rt;
- int result;
- mutex_lock(&uclamp_mutex);
- old_min = sysctl_sched_uclamp_util_min;
- old_max = sysctl_sched_uclamp_util_max;
- old_min_rt = sysctl_sched_uclamp_util_min_rt_default;
- result = proc_dointvec(table, write, buffer, lenp, ppos);
- if (result)
- goto undo;
- if (!write)
- goto done;
- if (sysctl_sched_uclamp_util_min > sysctl_sched_uclamp_util_max ||
- sysctl_sched_uclamp_util_max > SCHED_CAPACITY_SCALE ||
- sysctl_sched_uclamp_util_min_rt_default > SCHED_CAPACITY_SCALE) {
- result = -EINVAL;
- goto undo;
- }
- if (old_min != sysctl_sched_uclamp_util_min) {
- uclamp_se_set(&uclamp_default[UCLAMP_MIN],
- sysctl_sched_uclamp_util_min, false);
- update_root_tg = true;
- }
- if (old_max != sysctl_sched_uclamp_util_max) {
- uclamp_se_set(&uclamp_default[UCLAMP_MAX],
- sysctl_sched_uclamp_util_max, false);
- update_root_tg = true;
- }
- if (update_root_tg) {
- static_branch_enable(&sched_uclamp_used);
- uclamp_update_root_tg();
- }
- if (old_min_rt != sysctl_sched_uclamp_util_min_rt_default) {
- static_branch_enable(&sched_uclamp_used);
- uclamp_sync_util_min_rt_default();
- }
- /*
- * We update all RUNNABLE tasks only when task groups are in use.
- * Otherwise, keep it simple and do just a lazy update at each next
- * task enqueue time.
- */
- goto done;
- undo:
- sysctl_sched_uclamp_util_min = old_min;
- sysctl_sched_uclamp_util_max = old_max;
- sysctl_sched_uclamp_util_min_rt_default = old_min_rt;
- done:
- mutex_unlock(&uclamp_mutex);
- return result;
- }
- static int uclamp_validate(struct task_struct *p,
- const struct sched_attr *attr)
- {
- int util_min = p->uclamp_req[UCLAMP_MIN].value;
- int util_max = p->uclamp_req[UCLAMP_MAX].value;
- if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN) {
- util_min = attr->sched_util_min;
- if (util_min + 1 > SCHED_CAPACITY_SCALE + 1)
- return -EINVAL;
- }
- if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MAX) {
- util_max = attr->sched_util_max;
- if (util_max + 1 > SCHED_CAPACITY_SCALE + 1)
- return -EINVAL;
- }
- if (util_min != -1 && util_max != -1 && util_min > util_max)
- return -EINVAL;
- /*
- * We have valid uclamp attributes; make sure uclamp is enabled.
- *
- * We need to do that here, because enabling static branches is a
- * blocking operation which obviously cannot be done while holding
- * scheduler locks.
- */
- static_branch_enable(&sched_uclamp_used);
- return 0;
- }
- static bool uclamp_reset(const struct sched_attr *attr,
- enum uclamp_id clamp_id,
- struct uclamp_se *uc_se)
- {
- /* Reset on sched class change for a non user-defined clamp value. */
- if (likely(!(attr->sched_flags & SCHED_FLAG_UTIL_CLAMP)) &&
- !uc_se->user_defined)
- return true;
- /* Reset on sched_util_{min,max} == -1. */
- if (clamp_id == UCLAMP_MIN &&
- attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN &&
- attr->sched_util_min == -1) {
- return true;
- }
- if (clamp_id == UCLAMP_MAX &&
- attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MAX &&
- attr->sched_util_max == -1) {
- return true;
- }
- return false;
- }
- static void __setscheduler_uclamp(struct task_struct *p,
- const struct sched_attr *attr)
- {
- enum uclamp_id clamp_id;
- for_each_clamp_id(clamp_id) {
- struct uclamp_se *uc_se = &p->uclamp_req[clamp_id];
- unsigned int value;
- if (!uclamp_reset(attr, clamp_id, uc_se))
- continue;
- /*
- * RT by default have a 100% boost value that could be modified
- * at runtime.
- */
- if (unlikely(rt_task(p) && clamp_id == UCLAMP_MIN))
- value = sysctl_sched_uclamp_util_min_rt_default;
- else
- value = uclamp_none(clamp_id);
- uclamp_se_set(uc_se, value, false);
- }
- if (likely(!(attr->sched_flags & SCHED_FLAG_UTIL_CLAMP)))
- return;
- if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN &&
- attr->sched_util_min != -1) {
- uclamp_se_set(&p->uclamp_req[UCLAMP_MIN],
- attr->sched_util_min, true);
- trace_android_vh_setscheduler_uclamp(p, UCLAMP_MIN, attr->sched_util_min);
- }
- if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MAX &&
- attr->sched_util_max != -1) {
- uclamp_se_set(&p->uclamp_req[UCLAMP_MAX],
- attr->sched_util_max, true);
- trace_android_vh_setscheduler_uclamp(p, UCLAMP_MAX, attr->sched_util_max);
- }
- }
- static void uclamp_fork(struct task_struct *p)
- {
- enum uclamp_id clamp_id;
- /*
- * We don't need to hold task_rq_lock() when updating p->uclamp_* here
- * as the task is still at its early fork stages.
- */
- for_each_clamp_id(clamp_id)
- p->uclamp[clamp_id].active = false;
- if (likely(!p->sched_reset_on_fork))
- return;
- for_each_clamp_id(clamp_id) {
- uclamp_se_set(&p->uclamp_req[clamp_id],
- uclamp_none(clamp_id), false);
- }
- }
- static void uclamp_post_fork(struct task_struct *p)
- {
- uclamp_update_util_min_rt_default(p);
- }
- static void __init init_uclamp_rq(struct rq *rq)
- {
- enum uclamp_id clamp_id;
- struct uclamp_rq *uc_rq = rq->uclamp;
- for_each_clamp_id(clamp_id) {
- uc_rq[clamp_id] = (struct uclamp_rq) {
- .value = uclamp_none(clamp_id)
- };
- }
- rq->uclamp_flags = UCLAMP_FLAG_IDLE;
- }
- static void __init init_uclamp(void)
- {
- struct uclamp_se uc_max = {};
- enum uclamp_id clamp_id;
- int cpu;
- for_each_possible_cpu(cpu)
- init_uclamp_rq(cpu_rq(cpu));
- for_each_clamp_id(clamp_id) {
- uclamp_se_set(&init_task.uclamp_req[clamp_id],
- uclamp_none(clamp_id), false);
- }
- /* System defaults allow max clamp values for both indexes */
- uclamp_se_set(&uc_max, uclamp_none(UCLAMP_MAX), false);
- for_each_clamp_id(clamp_id) {
- uclamp_default[clamp_id] = uc_max;
- #ifdef CONFIG_UCLAMP_TASK_GROUP
- root_task_group.uclamp_req[clamp_id] = uc_max;
- root_task_group.uclamp[clamp_id] = uc_max;
- #endif
- }
- }
- #else /* CONFIG_UCLAMP_TASK */
- static inline void uclamp_rq_inc(struct rq *rq, struct task_struct *p) { }
- static inline void uclamp_rq_dec(struct rq *rq, struct task_struct *p) { }
- static inline int uclamp_validate(struct task_struct *p,
- const struct sched_attr *attr)
- {
- return -EOPNOTSUPP;
- }
- static void __setscheduler_uclamp(struct task_struct *p,
- const struct sched_attr *attr) { }
- static inline void uclamp_fork(struct task_struct *p) { }
- static inline void uclamp_post_fork(struct task_struct *p) { }
- static inline void init_uclamp(void) { }
- #endif /* CONFIG_UCLAMP_TASK */
- static inline void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
- {
- if (!(flags & ENQUEUE_NOCLOCK))
- update_rq_clock(rq);
- if (!(flags & ENQUEUE_RESTORE)) {
- sched_info_queued(rq, p);
- psi_enqueue(p, flags & ENQUEUE_WAKEUP);
- }
- uclamp_rq_inc(rq, p);
- trace_android_rvh_enqueue_task(rq, p, flags);
- p->sched_class->enqueue_task(rq, p, flags);
- trace_android_rvh_after_enqueue_task(rq, p);
- }
- static inline void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
- {
- if (!(flags & DEQUEUE_NOCLOCK))
- update_rq_clock(rq);
- if (!(flags & DEQUEUE_SAVE)) {
- sched_info_dequeued(rq, p);
- psi_dequeue(p, flags & DEQUEUE_SLEEP);
- }
- uclamp_rq_dec(rq, p);
- trace_android_rvh_dequeue_task(rq, p, flags);
- p->sched_class->dequeue_task(rq, p, flags);
- trace_android_rvh_after_dequeue_task(rq, p);
- }
- void activate_task(struct rq *rq, struct task_struct *p, int flags)
- {
- enqueue_task(rq, p, flags);
- p->on_rq = TASK_ON_RQ_QUEUED;
- }
- EXPORT_SYMBOL_GPL(activate_task);
- void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
- {
- p->on_rq = (flags & DEQUEUE_SLEEP) ? 0 : TASK_ON_RQ_MIGRATING;
- dequeue_task(rq, p, flags);
- }
- EXPORT_SYMBOL_GPL(deactivate_task);
- static inline int __normal_prio(int policy, int rt_prio, int nice)
- {
- int prio;
- if (dl_policy(policy))
- prio = MAX_DL_PRIO - 1;
- else if (rt_policy(policy))
- prio = MAX_RT_PRIO - 1 - rt_prio;
- else
- prio = NICE_TO_PRIO(nice);
- return 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)
- {
- return __normal_prio(p->policy, p->rt_priority, PRIO_TO_NICE(p->static_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;
- }
- /*
- * switched_from, switched_to and prio_changed must _NOT_ drop rq->lock,
- * use the balance_callback list if you want balancing.
- *
- * this means any call to check_class_changed() must be followed by a call to
- * balance_callback().
- */
- 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);
- 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)
- {
- if (p->sched_class == rq->curr->sched_class)
- rq->curr->sched_class->check_preempt_curr(rq, p, flags);
- else if (p->sched_class > rq->curr->sched_class)
- resched_curr(rq);
- /*
- * 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);
- }
- EXPORT_SYMBOL_GPL(check_preempt_curr);
- #ifdef CONFIG_SMP
- /*
- * Per-CPU kthreads are allowed to run on !active && online CPUs, see
- * __set_cpus_allowed_ptr() and select_fallback_rq().
- */
- static inline bool is_cpu_allowed(struct task_struct *p, int cpu)
- {
- if (!cpumask_test_cpu(cpu, p->cpus_ptr))
- return false;
- if (is_per_cpu_kthread(p))
- return cpu_online(cpu);
- if (!cpu_active(cpu))
- return false;
- return cpumask_test_cpu(cpu, task_cpu_possible_mask(p));
- }
- /*
- * 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.
- */
- /*
- * 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 rq *rq, struct rq_flags *rf,
- struct task_struct *p, int new_cpu)
- {
- int detached = 0;
- lockdep_assert_held(&rq->lock);
- /*
- * The vendor hook may drop the lock temporarily, so
- * pass the rq flags to unpin lock. We expect the
- * rq lock to be held after return.
- */
- trace_android_rvh_migrate_queued_task(rq, rf, p, new_cpu, &detached);
- if (detached)
- goto attach;
- deactivate_task(rq, p, DEQUEUE_NOCLOCK);
- set_task_cpu(p, new_cpu);
- attach:
- rq_unlock(rq, rf);
- rq = cpu_rq(new_cpu);
- rq_lock(rq, rf);
- BUG_ON(task_cpu(p) != new_cpu);
- activate_task(rq, p, 0);
- check_preempt_curr(rq, p, 0);
- return rq;
- }
- struct migration_arg {
- struct task_struct *task;
- int dest_cpu;
- };
- /*
- * Move (not current) task off this CPU, onto the destination 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.
- */
- static struct rq *__migrate_task(struct rq *rq, struct rq_flags *rf,
- struct task_struct *p, int dest_cpu)
- {
- /* Affinity changed (again). */
- if (!is_cpu_allowed(p, dest_cpu))
- return rq;
- update_rq_clock(rq);
- rq = move_queued_task(rq, rf, p, dest_cpu);
- return rq;
- }
- /*
- * 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;
- struct task_struct *p = arg->task;
- struct rq *rq = this_rq();
- struct rq_flags rf;
- /*
- * 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_ptr
- * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test.
- */
- flush_smp_call_function_from_idle();
- raw_spin_lock(&p->pi_lock);
- rq_lock(rq, &rf);
- /*
- * If task_rq(p) != rq, it cannot be migrated here, because we're
- * holding rq->lock, if p->on_rq == 0 it cannot get enqueued because
- * we're holding p->pi_lock.
- */
- if (task_rq(p) == rq) {
- if (task_on_rq_queued(p))
- rq = __migrate_task(rq, &rf, p, arg->dest_cpu);
- else
- p->wake_cpu = arg->dest_cpu;
- }
- rq_unlock(rq, &rf);
- raw_spin_unlock(&p->pi_lock);
- local_irq_enable();
- return 0;
- }
- /*
- * sched_class::set_cpus_allowed must do the below, but is not required to
- * actually call this function.
- */
- void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask)
- {
- cpumask_copy(&p->cpus_mask, new_mask);
- p->nr_cpus_allowed = cpumask_weight(new_mask);
- trace_android_rvh_set_cpus_allowed_comm(p, new_mask);
- }
- void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
- {
- struct rq *rq = task_rq(p);
- bool queued, running;
- lockdep_assert_held(&p->pi_lock);
- queued = task_on_rq_queued(p);
- running = task_current(rq, p);
- if (queued) {
- /*
- * Because __kthread_bind() calls this on blocked tasks without
- * holding rq->lock.
- */
- lockdep_assert_held(&rq->lock);
- dequeue_task(rq, p, DEQUEUE_SAVE | DEQUEUE_NOCLOCK);
- }
- if (running)
- put_prev_task(rq, p);
- p->sched_class->set_cpus_allowed(p, new_mask);
- if (queued)
- enqueue_task(rq, p, ENQUEUE_RESTORE | ENQUEUE_NOCLOCK);
- if (running)
- set_next_task(rq, p);
- }
- /*
- * Called with both p->pi_lock and rq->lock held; drops both before returning.
- */
- static int __set_cpus_allowed_ptr_locked(struct task_struct *p,
- const struct cpumask *new_mask,
- bool check,
- struct rq *rq,
- struct rq_flags *rf)
- {
- const struct cpumask *cpu_valid_mask = cpu_active_mask;
- const struct cpumask *cpu_allowed_mask = task_cpu_possible_mask(p);
- unsigned int dest_cpu;
- int ret = 0;
- update_rq_clock(rq);
- if (p->flags & PF_KTHREAD) {
- /*
- * Kernel threads are allowed on online && !active CPUs
- */
- cpu_valid_mask = cpu_online_mask;
- } else if (!cpumask_subset(new_mask, cpu_allowed_mask)) {
- ret = -EINVAL;
- goto out;
- }
- /*
- * Must re-check here, to close a race against __kthread_bind(),
- * sched_setaffinity() is not guaranteed to observe the flag.
- */
- if (check && (p->flags & PF_NO_SETAFFINITY)) {
- ret = -EINVAL;
- goto out;
- }
- if (cpumask_equal(&p->cpus_mask, new_mask))
- goto out;
- /*
- * Picking a ~random cpu helps in cases where we are changing affinity
- * for groups of tasks (ie. cpuset), so that load balancing is not
- * immediately required to distribute the tasks within their new mask.
- */
- dest_cpu = cpumask_any_and_distribute(cpu_valid_mask, new_mask);
- if (dest_cpu >= nr_cpu_ids) {
- ret = -EINVAL;
- goto out;
- }
- do_set_cpus_allowed(p, new_mask);
- if (p->flags & PF_KTHREAD) {
- /*
- * For kernel threads that do indeed end up on online &&
- * !active we want to ensure they are strict per-CPU threads.
- */
- WARN_ON(cpumask_intersects(new_mask, cpu_online_mask) &&
- !cpumask_intersects(new_mask, cpu_active_mask) &&
- p->nr_cpus_allowed != 1);
- }
- /* 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;
- 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, rf);
- stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
- return 0;
- } else if (task_on_rq_queued(p)) {
- /*
- * OK, since we're going to drop the lock immediately
- * afterwards anyway.
- */
- rq = move_queued_task(rq, rf, p, dest_cpu);
- }
- out:
- task_rq_unlock(rq, p, rf);
- return ret;
- }
- /*
- * 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.
- */
- static int __set_cpus_allowed_ptr(struct task_struct *p,
- const struct cpumask *new_mask, bool check)
- {
- struct rq_flags rf;
- struct rq *rq;
- rq = task_rq_lock(p, &rf);
- return __set_cpus_allowed_ptr_locked(p, new_mask, check, rq, &rf);
- }
- int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
- {
- return __set_cpus_allowed_ptr(p, new_mask, false);
- }
- EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
- /*
- * Change a given task's CPU affinity to the intersection of its current
- * affinity mask and @subset_mask, writing the resulting mask to @new_mask.
- * If the resulting mask is empty, leave the affinity unchanged and return
- * -EINVAL.
- */
- static int restrict_cpus_allowed_ptr(struct task_struct *p,
- struct cpumask *new_mask,
- const struct cpumask *subset_mask)
- {
- struct rq_flags rf;
- struct rq *rq;
- rq = task_rq_lock(p, &rf);
- if (!cpumask_and(new_mask, &p->cpus_mask, subset_mask)) {
- task_rq_unlock(rq, p, &rf);
- return -EINVAL;
- }
- return __set_cpus_allowed_ptr_locked(p, new_mask, false, rq, &rf);
- }
- /*
- * Restrict a given task's CPU affinity so that it is a subset of
- * task_cpu_possible_mask(). If the resulting mask is empty, we warn and
- * walk up the cpuset hierarchy until we find a suitable mask.
- */
- void force_compatible_cpus_allowed_ptr(struct task_struct *p)
- {
- cpumask_var_t new_mask;
- const struct cpumask *override_mask = task_cpu_possible_mask(p);
- alloc_cpumask_var(&new_mask, GFP_KERNEL);
- /*
- * __migrate_task() can fail silently in the face of concurrent
- * offlining of the chosen destination CPU, so take the hotplug
- * lock to ensure that the migration succeeds.
- */
- trace_android_rvh_force_compatible_pre(NULL);
- cpus_read_lock();
- if (!cpumask_available(new_mask))
- goto out_set_mask;
- if (!restrict_cpus_allowed_ptr(p, new_mask, override_mask))
- goto out_free_mask;
- /*
- * We failed to find a valid subset of the affinity mask for the
- * task, so override it based on its cpuset hierarchy.
- */
- cpuset_cpus_allowed(p, new_mask);
- override_mask = new_mask;
- out_set_mask:
- if (printk_ratelimit()) {
- printk_deferred("Overriding affinity for process %d (%s) to CPUs %*pbl\n",
- task_pid_nr(p), p->comm,
- cpumask_pr_args(override_mask));
- }
- WARN_ON(set_cpus_allowed_ptr(p, override_mask));
- out_free_mask:
- cpus_read_unlock();
- trace_android_rvh_force_compatible_post(NULL);
- free_cpumask_var(new_mask);
- }
- 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);
- /*
- * Migrating fair class task must have p->on_rq = TASK_ON_RQ_MIGRATING,
- * because schedstat_wait_{start,end} rebase migrating task's wait_start
- * time relying on p->on_rq.
- */
- WARN_ON_ONCE(p->state == TASK_RUNNING &&
- p->sched_class == &fair_sched_class &&
- (p->on_rq && !task_on_rq_migrating(p)));
- #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
- /*
- * Clearly, migrating tasks to offline CPUs is a fairly daft thing.
- */
- WARN_ON_ONCE(!cpu_online(new_cpu));
- #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++;
- rseq_migrate(p);
- perf_event_task_migrate(p);
- trace_android_rvh_set_task_cpu(p, new_cpu);
- }
- __set_task_cpu(p, new_cpu);
- }
- EXPORT_SYMBOL_GPL(set_task_cpu);
- static void __migrate_swap_task(struct task_struct *p, int cpu)
- {
- if (task_on_rq_queued(p)) {
- struct rq *src_rq, *dst_rq;
- struct rq_flags srf, drf;
- src_rq = task_rq(p);
- dst_rq = cpu_rq(cpu);
- rq_pin_lock(src_rq, &srf);
- rq_pin_lock(dst_rq, &drf);
- deactivate_task(src_rq, p, 0);
- set_task_cpu(p, cpu);
- activate_task(dst_rq, p, 0);
- check_preempt_curr(dst_rq, p, 0);
- rq_unpin_lock(dst_rq, &drf);
- rq_unpin_lock(src_rq, &srf);
- } 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 target 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;
- if (!cpu_active(arg->src_cpu) || !cpu_active(arg->dst_cpu))
- return -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, arg->src_task->cpus_ptr))
- goto unlock;
- if (!cpumask_test_cpu(arg->src_cpu, arg->dst_task->cpus_ptr))
- 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,
- int target_cpu, int curr_cpu)
- {
- struct migration_swap_arg arg;
- int ret = -EINVAL;
- arg = (struct migration_swap_arg){
- .src_task = cur,
- .src_cpu = curr_cpu,
- .dst_task = p,
- .dst_cpu = target_cpu,
- };
- 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, arg.src_task->cpus_ptr))
- goto out;
- if (!cpumask_test_cpu(arg.src_cpu, arg.dst_task->cpus_ptr))
- 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;
- }
- EXPORT_SYMBOL_GPL(migrate_swap);
- /*
- * 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)
- {
- int running, queued;
- struct rq_flags rf;
- 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, &rf);
- 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, &rf);
- /*
- * 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 = 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);
- /*
- * ->cpus_ptr is protected by both rq->lock and p->pi_lock
- *
- * A few notes on cpu_active vs cpu_online:
- *
- * - cpu_active must be a subset of cpu_online
- *
- * - on CPU-up we allow per-CPU kthreads on the online && !active CPU,
- * see __set_cpus_allowed_ptr(). At this point the newly online
- * CPU isn't yet part of the sched domains, and balancing will not
- * see it.
- *
- * - on CPU-down we clear cpu_active() to mask the sched domains and
- * avoid the load balancer to place new tasks on the to be removed
- * CPU. Existing tasks will remain running there and will be taken
- * off.
- *
- * This means that fallback selection must not select !active CPUs.
- * And can assume that any active CPU must be online. Conversely
- * select_task_rq() below may allow selection of !active CPUs in order
- * to satisfy the above rules.
- */
- 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 = -1;
- trace_android_rvh_select_fallback_rq(cpu, p, &dest_cpu);
- if (dest_cpu >= 0)
- return dest_cpu;
- /*
- * 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);
- /* Look for allowed, online CPU in same node. */
- for_each_cpu(dest_cpu, nodemask) {
- if (is_cpu_allowed(p, dest_cpu))
- return dest_cpu;
- }
- }
- for (;;) {
- /* Any allowed, online CPU? */
- for_each_cpu(dest_cpu, p->cpus_ptr) {
- if (!is_cpu_allowed(p, dest_cpu))
- continue;
- goto out;
- }
- /* No more Mr. Nice Guy. */
- switch (state) {
- case cpuset:
- if (IS_ENABLED(CONFIG_CPUSETS)) {
- cpuset_cpus_allowed_fallback(p);
- state = possible;
- break;
- }
- fallthrough;
- case possible:
- do_set_cpus_allowed(p, task_cpu_possible_mask(p));
- 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;
- }
- /*
- * The caller (fork, wakeup) owns p->pi_lock, ->cpus_ptr is stable.
- */
- static inline
- int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags)
- {
- lockdep_assert_held(&p->pi_lock);
- if (p->nr_cpus_allowed > 1)
- cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags);
- else
- cpu = cpumask_any(p->cpus_ptr);
- /*
- * 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_ptr
- * 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(!is_cpu_allowed(p, cpu)))
- cpu = select_fallback_rq(task_cpu(p), p);
- return cpu;
- }
- 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;
- }
- }
- #else
- static inline int __set_cpus_allowed_ptr(struct task_struct *p,
- const struct cpumask *new_mask, bool check)
- {
- return set_cpus_allowed_ptr(p, new_mask);
- }
- #endif /* CONFIG_SMP */
- static void
- ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
- {
- struct rq *rq;
- if (!schedstat_enabled())
- return;
- rq = this_rq();
- #ifdef CONFIG_SMP
- if (cpu == rq->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(rq->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);
- }
- /*
- * Mark the task runnable and perform wakeup-preemption.
- */
- static void ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags,
- struct rq_flags *rf)
- {
- check_preempt_curr(rq, p, wake_flags);
- p->state = TASK_RUNNING;
- trace_sched_wakeup(p);
- #ifdef CONFIG_SMP
- if (p->sched_class->task_woken) {
- /*
- * Our task @p is fully woken up and running; so its safe to
- * drop the rq->lock, hereafter rq is only used for statistics.
- */
- rq_unpin_lock(rq, rf);
- p->sched_class->task_woken(rq, p);
- rq_repin_lock(rq, rf);
- }
- 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,
- struct rq_flags *rf)
- {
- int en_flags = ENQUEUE_WAKEUP | ENQUEUE_NOCLOCK;
- if (wake_flags & WF_SYNC)
- en_flags |= ENQUEUE_WAKEUP_SYNC;
- lockdep_assert_held(&rq->lock);
- if (p->sched_contributes_to_load)
- rq->nr_uninterruptible--;
- #ifdef CONFIG_SMP
- if (wake_flags & WF_MIGRATED)
- en_flags |= ENQUEUE_MIGRATED;
- else
- #endif
- if (p->in_iowait) {
- delayacct_blkio_end(p);
- atomic_dec(&task_rq(p)->nr_iowait);
- }
- activate_task(rq, p, en_flags);
- ttwu_do_wakeup(rq, p, wake_flags, rf);
- }
- /*
- * Consider @p being inside a wait loop:
- *
- * for (;;) {
- * set_current_state(TASK_UNINTERRUPTIBLE);
- *
- * if (CONDITION)
- * break;
- *
- * schedule();
- * }
- * __set_current_state(TASK_RUNNING);
- *
- * between set_current_state() and schedule(). In this case @p is still
- * runnable, so all that needs doing is change p->state back to TASK_RUNNING in
- * an atomic manner.
- *
- * By taking task_rq(p)->lock we serialize against schedule(), if @p->on_rq
- * then schedule() must still happen and p->state can be changed to
- * TASK_RUNNING. Otherwise we lost the race, schedule() has happened, and we
- * need to do a full wakeup with enqueue.
- *
- * Returns: %true when the wakeup is done,
- * %false otherwise.
- */
- static int ttwu_runnable(struct task_struct *p, int wake_flags)
- {
- struct rq_flags rf;
- struct rq *rq;
- int ret = 0;
- rq = __task_rq_lock(p, &rf);
- if (task_on_rq_queued(p)) {
- /* check_preempt_curr() may use rq clock */
- update_rq_clock(rq);
- ttwu_do_wakeup(rq, p, wake_flags, &rf);
- ret = 1;
- }
- __task_rq_unlock(rq, &rf);
- return ret;
- }
- #ifdef CONFIG_SMP
- void sched_ttwu_pending(void *arg)
- {
- struct llist_node *llist = arg;
- struct rq *rq = this_rq();
- struct task_struct *p, *t;
- struct rq_flags rf;
- if (!llist)
- return;
- /*
- * rq::ttwu_pending racy indication of out-standing wakeups.
- * Races such that false-negatives are possible, since they
- * are shorter lived that false-positives would be.
- */
- WRITE_ONCE(rq->ttwu_pending, 0);
- rq_lock_irqsave(rq, &rf);
- update_rq_clock(rq);
- llist_for_each_entry_safe(p, t, llist, wake_entry.llist) {
- if (WARN_ON_ONCE(p->on_cpu))
- smp_cond_load_acquire(&p->on_cpu, !VAL);
- if (WARN_ON_ONCE(task_cpu(p) != cpu_of(rq)))
- set_task_cpu(p, cpu_of(rq));
- ttwu_do_activate(rq, p, p->sched_remote_wakeup ? WF_MIGRATED : 0, &rf);
- }
- rq_unlock_irqrestore(rq, &rf);
- }
- void send_call_function_single_ipi(int cpu)
- {
- struct rq *rq = cpu_rq(cpu);
- if (!set_nr_if_polling(rq->idle))
- arch_send_call_function_single_ipi(cpu);
- else
- trace_sched_wake_idle_without_ipi(cpu);
- }
- /*
- * Queue a task on the target CPUs wake_list and wake the CPU via IPI if
- * necessary. The wakee CPU on receipt of the IPI will queue the task
- * via sched_ttwu_wakeup() for activation so the wakee incurs the cost
- * of the wakeup instead of the waker.
- */
- static void __ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
- {
- struct rq *rq = cpu_rq(cpu);
- p->sched_remote_wakeup = !!(wake_flags & WF_MIGRATED);
- WRITE_ONCE(rq->ttwu_pending, 1);
- __smp_call_single_queue(cpu, &p->wake_entry.llist);
- }
- void wake_up_if_idle(int cpu)
- {
- struct rq *rq = cpu_rq(cpu);
- struct rq_flags rf;
- 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 {
- rq_lock_irqsave(rq, &rf);
- if (is_idle_task(rq->curr))
- smp_send_reschedule(cpu);
- /* Else CPU is not idle, do nothing here: */
- rq_unlock_irqrestore(rq, &rf);
- }
- out:
- rcu_read_unlock();
- }
- EXPORT_SYMBOL_GPL(wake_up_if_idle);
- bool cpus_share_cache(int this_cpu, int that_cpu)
- {
- if (this_cpu == that_cpu)
- return true;
- return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
- }
- static inline bool ttwu_queue_cond(int cpu, int wake_flags)
- {
- /*
- * If the CPU does not share cache, then queue the task on the
- * remote rqs wakelist to avoid accessing remote data.
- */
- if (!cpus_share_cache(smp_processor_id(), cpu))
- return true;
- /*
- * If the task is descheduling and the only running task on the
- * CPU then use the wakelist to offload the task activation to
- * the soon-to-be-idle CPU as the current CPU is likely busy.
- * nr_running is checked to avoid unnecessary task stacking.
- */
- if ((wake_flags & WF_ON_CPU) && cpu_rq(cpu)->nr_running <= 1)
- return true;
- return false;
- }
- static bool ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
- {
- bool cond = false;
- trace_android_rvh_ttwu_cond(&cond);
- if ((sched_feat(TTWU_QUEUE) && ttwu_queue_cond(cpu, wake_flags)) ||
- cond) {
- if (WARN_ON_ONCE(cpu == smp_processor_id()))
- return false;
- sched_clock_cpu(cpu); /* Sync clocks across CPUs */
- __ttwu_queue_wakelist(p, cpu, wake_flags);
- return true;
- }
- return false;
- }
- #else /* !CONFIG_SMP */
- static inline bool ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
- {
- return false;
- }
- #endif /* CONFIG_SMP */
- static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags)
- {
- struct rq *rq = cpu_rq(cpu);
- struct rq_flags rf;
- if (ttwu_queue_wakelist(p, cpu, wake_flags))
- return;
- rq_lock(rq, &rf);
- update_rq_clock(rq);
- ttwu_do_activate(rq, p, wake_flags, &rf);
- rq_unlock(rq, &rf);
- }
- /*
- * Notes on Program-Order guarantees on SMP systems.
- *
- * MIGRATION
- *
- * The basic program-order guarantee on SMP systems is that when a task [t]
- * migrates, all its activity on its old CPU [c0] happens-before any subsequent
- * execution on its new CPU [c1].
- *
- * For migration (of runnable tasks) this is provided by the following means:
- *
- * A) UNLOCK of the rq(c0)->lock scheduling out task t
- * B) migration for t is required to synchronize *both* rq(c0)->lock and
- * rq(c1)->lock (if not at the same time, then in that order).
- * C) LOCK of the rq(c1)->lock scheduling in task
- *
- * Release/acquire chaining guarantees that B happens after A and C after B.
- * Note: the CPU doing B need not be c0 or c1
- *
- * Example:
- *
- * CPU0 CPU1 CPU2
- *
- * LOCK rq(0)->lock
- * sched-out X
- * sched-in Y
- * UNLOCK rq(0)->lock
- *
- * LOCK rq(0)->lock // orders against CPU0
- * dequeue X
- * UNLOCK rq(0)->lock
- *
- * LOCK rq(1)->lock
- * enqueue X
- * UNLOCK rq(1)->lock
- *
- * LOCK rq(1)->lock // orders against CPU2
- * sched-out Z
- * sched-in X
- * UNLOCK rq(1)->lock
- *
- *
- * BLOCKING -- aka. SLEEP + WAKEUP
- *
- * For blocking we (obviously) need to provide the same guarantee as for
- * migration. However the means are completely different as there is no lock
- * chain to provide order. Instead we do:
- *
- * 1) smp_store_release(X->on_cpu, 0) -- finish_task()
- * 2) smp_cond_load_acquire(!X->on_cpu) -- try_to_wake_up()
- *
- * Example:
- *
- * CPU0 (schedule) CPU1 (try_to_wake_up) CPU2 (schedule)
- *
- * LOCK rq(0)->lock LOCK X->pi_lock
- * dequeue X
- * sched-out X
- * smp_store_release(X->on_cpu, 0);
- *
- * smp_cond_load_acquire(&X->on_cpu, !VAL);
- * X->state = WAKING
- * set_task_cpu(X,2)
- *
- * LOCK rq(2)->lock
- * enqueue X
- * X->state = RUNNING
- * UNLOCK rq(2)->lock
- *
- * LOCK rq(2)->lock // orders against CPU1
- * sched-out Z
- * sched-in X
- * UNLOCK rq(2)->lock
- *
- * UNLOCK X->pi_lock
- * UNLOCK rq(0)->lock
- *
- *
- * However, for wakeups there is a second guarantee we must provide, namely we
- * must ensure that CONDITION=1 done by the caller can not be reordered with
- * accesses to the task state; see try_to_wake_up() and set_current_state().
- */
- /**
- * 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_*)
- *
- * Conceptually does:
- *
- * If (@state & @p->state) @p->state = TASK_RUNNING.
- *
- * If the task was not queued/runnable, also place it back on a runqueue.
- *
- * This function is atomic against schedule() which would dequeue the task.
- *
- * It issues a full memory barrier before accessing @p->state, see the comment
- * with set_current_state().
- *
- * Uses p->pi_lock to serialize against concurrent wake-ups.
- *
- * Relies on p->pi_lock stabilizing:
- * - p->sched_class
- * - p->cpus_ptr
- * - p->sched_task_group
- * in order to do migration, see its use of select_task_rq()/set_task_cpu().
- *
- * Tries really hard to only take one task_rq(p)->lock for performance.
- * Takes rq->lock in:
- * - ttwu_runnable() -- old rq, unavoidable, see comment there;
- * - ttwu_queue() -- new rq, for enqueue of the task;
- * - psi_ttwu_dequeue() -- much sadness :-( accounting will kill us.
- *
- * As a consequence we race really badly with just about everything. See the
- * many memory barriers and their comments for details.
- *
- * Return: %true if @p->state changes (an actual wakeup was done),
- * %false otherwise.
- */
- static int
- try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
- {
- unsigned long flags;
- int cpu, success = 0;
- preempt_disable();
- if (p == current) {
- /*
- * We're waking current, this means 'p->on_rq' and 'task_cpu(p)
- * == smp_processor_id()'. Together this means we can special
- * case the whole 'p->on_rq && ttwu_runnable()' case below
- * without taking any locks.
- *
- * In particular:
- * - we rely on Program-Order guarantees for all the ordering,
- * - we're serialized against set_special_state() by virtue of
- * it disabling IRQs (this allows not taking ->pi_lock).
- */
- if (!(p->state & state))
- goto out;
- success = 1;
- trace_sched_waking(p);
- p->state = TASK_RUNNING;
- trace_sched_wakeup(p);
- goto out;
- }
- /*
- * 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 smp_store_mb()
- * in set_current_state() that the waiting thread does.
- */
- raw_spin_lock_irqsave(&p->pi_lock, flags);
- smp_mb__after_spinlock();
- if (!(p->state & state))
- goto unlock;
- #ifdef CONFIG_FREEZER
- /*
- * If we're going to wake up a thread which may be frozen, then
- * we can only do so if we have an active CPU which is capable of
- * running it. This may not be the case when resuming from suspend,
- * as the secondary CPUs may not yet be back online. See __thaw_task()
- * for the actual wakeup.
- */
- if (unlikely(frozen_or_skipped(p)) &&
- !cpumask_intersects(cpu_active_mask, task_cpu_possible_mask(p)))
- goto unlock;
- #endif
- trace_sched_waking(p);
- /* We're going to change ->state: */
- success = 1;
- /*
- * 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()
- * STORE p->on_rq = 1 LOAD p->state
- * UNLOCK rq->lock
- *
- * __schedule() (switch to task 'p')
- * LOCK rq->lock smp_rmb();
- * smp_mb__after_spinlock();
- * UNLOCK rq->lock
- *
- * [task p]
- * STORE p->state = UNINTERRUPTIBLE LOAD p->on_rq
- *
- * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in
- * __schedule(). See the comment for smp_mb__after_spinlock().
- *
- * A similar smb_rmb() lives in try_invoke_on_locked_down_task().
- */
- smp_rmb();
- if (READ_ONCE(p->on_rq) && ttwu_runnable(p, wake_flags))
- goto unlock;
- if (p->state & TASK_UNINTERRUPTIBLE)
- trace_sched_blocked_reason(p);
- #ifdef CONFIG_SMP
- /*
- * Ensure we load p->on_cpu _after_ p->on_rq, otherwise it would be
- * possible to, falsely, observe p->on_cpu == 0.
- *
- * One must be running (->on_cpu == 1) in order to remove oneself
- * from the runqueue.
- *
- * __schedule() (switch to task 'p') try_to_wake_up()
- * STORE p->on_cpu = 1 LOAD p->on_rq
- * UNLOCK rq->lock
- *
- * __schedule() (put 'p' to sleep)
- * LOCK rq->lock smp_rmb();
- * smp_mb__after_spinlock();
- * STORE p->on_rq = 0 LOAD p->on_cpu
- *
- * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in
- * __schedule(). See the comment for smp_mb__after_spinlock().
- *
- * Form a control-dep-acquire with p->on_rq == 0 above, to ensure
- * schedule()'s deactivate_task() has 'happened' and p will no longer
- * care about it's own p->state. See the comment in __schedule().
- */
- smp_acquire__after_ctrl_dep();
- /*
- * We're doing the wakeup (@success == 1), they did a dequeue (p->on_rq
- * == 0), which means we need to do an enqueue, change p->state to
- * TASK_WAKING such that we can unlock p->pi_lock before doing the
- * enqueue, such as ttwu_queue_wakelist().
- */
- p->state = TASK_WAKING;
- /*
- * If the owning (remote) CPU is still in the middle of schedule() with
- * this task as prev, considering queueing p on the remote CPUs wake_list
- * which potentially sends an IPI instead of spinning on p->on_cpu to
- * let the waker make forward progress. This is safe because IRQs are
- * disabled and the IPI will deliver after on_cpu is cleared.
- *
- * Ensure we load task_cpu(p) after p->on_cpu:
- *
- * set_task_cpu(p, cpu);
- * STORE p->cpu = @cpu
- * __schedule() (switch to task 'p')
- * LOCK rq->lock
- * smp_mb__after_spin_lock() smp_cond_load_acquire(&p->on_cpu)
- * STORE p->on_cpu = 1 LOAD p->cpu
- *
- * to ensure we observe the correct CPU on which the task is currently
- * scheduling.
- */
- if (smp_load_acquire(&p->on_cpu) &&
- ttwu_queue_wakelist(p, task_cpu(p), wake_flags | WF_ON_CPU))
- goto unlock;
- /*
- * If the owning (remote) CPU is still in the middle of schedule() with
- * this task as prev, wait until its done referencing the task.
- *
- * Pairs with the smp_store_release() in finish_task().
- *
- * This ensures that tasks getting woken will be fully ordered against
- * their previous state and preserve Program Order.
- */
- smp_cond_load_acquire(&p->on_cpu, !VAL);
- trace_android_rvh_try_to_wake_up(p);
- cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags);
- if (task_cpu(p) != cpu) {
- if (p->in_iowait) {
- delayacct_blkio_end(p);
- atomic_dec(&task_rq(p)->nr_iowait);
- }
- wake_flags |= WF_MIGRATED;
- psi_ttwu_dequeue(p);
- set_task_cpu(p, cpu);
- }
- #else
- cpu = task_cpu(p);
- #endif /* CONFIG_SMP */
- ttwu_queue(p, cpu, wake_flags);
- unlock:
- raw_spin_unlock_irqrestore(&p->pi_lock, flags);
- out:
- if (success) {
- trace_android_rvh_try_to_wake_up_success(p);
- ttwu_stat(p, task_cpu(p), wake_flags);
- }
- preempt_enable();
- return success;
- }
- /**
- * try_invoke_on_locked_down_task - Invoke a function on task in fixed state
- * @p: Process for which the function is to be invoked, can be @current.
- * @func: Function to invoke.
- * @arg: Argument to function.
- *
- * If the specified task can be quickly locked into a definite state
- * (either sleeping or on a given runqueue), arrange to keep it in that
- * state while invoking @func(@arg). This function can use ->on_rq and
- * task_curr() to work out what the state is, if required. Given that
- * @func can be invoked with a runqueue lock held, it had better be quite
- * lightweight.
- *
- * Returns:
- * @false if the task slipped out from under the locks.
- * @true if the task was locked onto a runqueue or is sleeping.
- * However, @func can override this by returning @false.
- */
- bool try_invoke_on_locked_down_task(struct task_struct *p, bool (*func)(struct task_struct *t, void *arg), void *arg)
- {
- struct rq_flags rf;
- bool ret = false;
- struct rq *rq;
- raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
- if (p->on_rq) {
- rq = __task_rq_lock(p, &rf);
- if (task_rq(p) == rq)
- ret = func(p, arg);
- rq_unlock(rq, &rf);
- } else {
- switch (p->state) {
- case TASK_RUNNING:
- case TASK_WAKING:
- break;
- default:
- smp_rmb(); // See smp_rmb() comment in try_to_wake_up().
- if (!p->on_rq)
- ret = func(p, arg);
- }
- }
- raw_spin_unlock_irqrestore(&p->pi_lock, rf.flags);
- return ret;
- }
- /**
- * 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.
- *
- * This function executes a full memory barrier before accessing the task state.
- */
- int wake_up_process(struct task_struct *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);
- }
- /*
- * 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;
- INIT_LIST_HEAD(&p->se.group_node);
- #ifdef CONFIG_FAIR_GROUP_SCHED
- p->se.cfs_rq = NULL;
- #endif
- trace_android_rvh_sched_fork_init(p);
- #ifdef CONFIG_SCHEDSTATS
- /* Even if schedstat is disabled, there should not be garbage */
- memset(&p->se.statistics, 0, sizeof(p->se.statistics));
- #endif
- RB_CLEAR_NODE(&p->dl.rb_node);
- init_dl_task_timer(&p->dl);
- init_dl_inactive_task_timer(&p->dl);
- __dl_clear_params(p);
- INIT_LIST_HEAD(&p->rt.run_list);
- p->rt.timeout = 0;
- p->rt.time_slice = sched_rr_timeslice;
- p->rt.on_rq = 0;
- p->rt.on_list = 0;
- #ifdef CONFIG_PREEMPT_NOTIFIERS
- INIT_HLIST_HEAD(&p->preempt_notifiers);
- #endif
- #ifdef CONFIG_COMPACTION
- p->capture_control = NULL;
- #endif
- init_numa_balancing(clone_flags, p);
- #ifdef CONFIG_SMP
- p->wake_entry.u_flags = CSD_TYPE_TTWU;
- #endif
- }
- DEFINE_STATIC_KEY_FALSE(sched_numa_balancing);
- #ifdef CONFIG_NUMA_BALANCING
- void set_numabalancing_state(bool enabled)
- {
- if (enabled)
- static_branch_enable(&sched_numa_balancing);
- else
- static_branch_disable(&sched_numa_balancing);
- }
- #ifdef CONFIG_PROC_SYSCTL
- int sysctl_numa_balancing(struct ctl_table *table, int write,
- void *buffer, size_t *lenp, loff_t *ppos)
- {
- struct ctl_table t;
- int err;
- int state = static_branch_likely(&sched_numa_balancing);
- 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
- #ifdef CONFIG_SCHEDSTATS
- DEFINE_STATIC_KEY_FALSE(sched_schedstats);
- static bool __initdata __sched_schedstats = false;
- static void set_schedstats(bool enabled)
- {
- if (enabled)
- static_branch_enable(&sched_schedstats);
- else
- static_branch_disable(&sched_schedstats);
- }
- void force_schedstat_enabled(void)
- {
- if (!schedstat_enabled()) {
- pr_info("kernel profiling enabled schedstats, disable via kernel.sched_schedstats.\n");
- static_branch_enable(&sched_schedstats);
- }
- }
- static int __init setup_schedstats(char *str)
- {
- int ret = 0;
- if (!str)
- goto out;
- /*
- * This code is called before jump labels have been set up, so we can't
- * change the static branch directly just yet. Instead set a temporary
- * variable so init_schedstats() can do it later.
- */
- if (!strcmp(str, "enable")) {
- __sched_schedstats = true;
- ret = 1;
- } else if (!strcmp(str, "disable")) {
- __sched_schedstats = false;
- ret = 1;
- }
- out:
- if (!ret)
- pr_warn("Unable to parse schedstats=\n");
- return ret;
- }
- __setup("schedstats=", setup_schedstats);
- static void __init init_schedstats(void)
- {
- set_schedstats(__sched_schedstats);
- }
- #ifdef CONFIG_PROC_SYSCTL
- int sysctl_schedstats(struct ctl_table *table, int write, void *buffer,
- size_t *lenp, loff_t *ppos)
- {
- struct ctl_table t;
- int err;
- int state = static_branch_likely(&sched_schedstats);
- 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_schedstats(state);
- return err;
- }
- #endif /* CONFIG_PROC_SYSCTL */
- #else /* !CONFIG_SCHEDSTATS */
- static inline void init_schedstats(void) {}
- #endif /* CONFIG_SCHEDSTATS */
- /*
- * fork()/clone()-time setup:
- */
- int sched_fork(unsigned long clone_flags, struct task_struct *p)
- {
- trace_android_rvh_sched_fork(p);
- __sched_fork(clone_flags, p);
- /*
- * We mark the process as NEW 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_NEW;
- /*
- * Make sure we do not leak PI boosting priority to the child.
- */
- p->prio = current->normal_prio;
- trace_android_rvh_prepare_prio_fork(p);
- uclamp_fork(p);
- /*
- * 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 = p->static_prio;
- set_load_weight(p, false);
- /*
- * 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))
- return -EAGAIN;
- else if (rt_prio(p->prio))
- p->sched_class = &rt_sched_class;
- else
- p->sched_class = &fair_sched_class;
- init_entity_runnable_average(&p->se);
- trace_android_rvh_finish_prio_fork(p);
- #ifdef CONFIG_SCHED_INFO
- 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
- return 0;
- }
- void sched_cgroup_fork(struct task_struct *p, struct kernel_clone_args *kargs)
- {
- unsigned long flags;
- /*
- * Because we're not yet on the pid-hash, p->pi_lock isn't strictly
- * required yet, but lockdep gets upset if rules are violated.
- */
- raw_spin_lock_irqsave(&p->pi_lock, flags);
- #ifdef CONFIG_CGROUP_SCHED
- if (1) {
- struct task_group *tg;
- tg = container_of(kargs->cset->subsys[cpu_cgrp_id],
- struct task_group, css);
- tg = autogroup_task_group(p, tg);
- p->sched_task_group = tg;
- }
- #endif
- rseq_migrate(p);
- /*
- * We're setting the CPU for the first time, we don't migrate,
- * so use __set_task_cpu().
- */
- __set_task_cpu(p, smp_processor_id());
- if (p->sched_class->task_fork)
- p->sched_class->task_fork(p);
- raw_spin_unlock_irqrestore(&p->pi_lock, flags);
- }
- void sched_post_fork(struct task_struct *p)
- {
- uclamp_post_fork(p);
- }
- unsigned long to_ratio(u64 period, u64 runtime)
- {
- if (runtime == RUNTIME_INF)
- return BW_UNIT;
- /*
- * 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 << BW_SHIFT, period);
- }
- /*
- * 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)
- {
- struct rq_flags rf;
- struct rq *rq;
- trace_android_rvh_wake_up_new_task(p);
- raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
- p->state = TASK_RUNNING;
- #ifdef CONFIG_SMP
- /*
- * Fork balancing, do it here and not earlier because:
- * - cpus_ptr can change in the fork path
- * - any previously selected CPU might disappear through hotplug
- *
- * Use __set_task_cpu() to avoid calling sched_class::migrate_task_rq,
- * as we're not fully set-up yet.
- */
- p->recent_used_cpu = task_cpu(p);
- rseq_migrate(p);
- __set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0));
- #endif
- rq = __task_rq_lock(p, &rf);
- update_rq_clock(rq);
- post_init_entity_util_avg(p);
- trace_android_rvh_new_task_stats(p);
- activate_task(rq, p, ENQUEUE_NOCLOCK);
- trace_sched_wakeup_new(p);
- check_preempt_curr(rq, p, WF_FORK);
- #ifdef CONFIG_SMP
- if (p->sched_class->task_woken) {
- /*
- * Nothing relies on rq->lock after this, so its fine to
- * drop it.
- */
- rq_unpin_lock(rq, &rf);
- p->sched_class->task_woken(rq, p);
- rq_repin_lock(rq, &rf);
- }
- #endif
- task_rq_unlock(rq, p, &rf);
- }
- #ifdef CONFIG_PREEMPT_NOTIFIERS
- static DEFINE_STATIC_KEY_FALSE(preempt_notifier_key);
- void preempt_notifier_inc(void)
- {
- static_branch_inc(&preempt_notifier_key);
- }
- EXPORT_SYMBOL_GPL(preempt_notifier_inc);
- void preempt_notifier_dec(void)
- {
- static_branch_dec(&preempt_notifier_key);
- }
- EXPORT_SYMBOL_GPL(preempt_notifier_dec);
- /**
- * preempt_notifier_register - tell me when current is being preempted & rescheduled
- * @notifier: notifier struct to register
- */
- void preempt_notifier_register(struct preempt_notifier *notifier)
- {
- if (!static_branch_unlikely(&preempt_notifier_key))
- WARN(1, "registering preempt_notifier while notifiers disabled\n");
- 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 *not* 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 __always_inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
- {
- if (static_branch_unlikely(&preempt_notifier_key))
- __fire_sched_in_preempt_notifiers(curr);
- }
- 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);
- }
- static __always_inline void
- fire_sched_out_preempt_notifiers(struct task_struct *curr,
- struct task_struct *next)
- {
- if (static_branch_unlikely(&preempt_notifier_key))
- __fire_sched_out_preempt_notifiers(curr, next);
- }
- #else /* !CONFIG_PREEMPT_NOTIFIERS */
- static inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
- {
- }
- static inline void
- fire_sched_out_preempt_notifiers(struct task_struct *curr,
- struct task_struct *next)
- {
- }
- #endif /* CONFIG_PREEMPT_NOTIFIERS */
- static inline void prepare_task(struct task_struct *next)
- {
- #ifdef CONFIG_SMP
- /*
- * Claim the task as running, we do this before switching to it
- * such that any running task will have this set.
- *
- * See the ttwu() WF_ON_CPU case and its ordering comment.
- */
- WRITE_ONCE(next->on_cpu, 1);
- #endif
- }
- static inline void finish_task(struct task_struct *prev)
- {
- #ifdef CONFIG_SMP
- /*
- * This must be the very last reference to @prev from this CPU. After
- * p->on_cpu is cleared, the task can be moved to a different CPU. We
- * must ensure this doesn't happen until the switch is completely
- * finished.
- *
- * In particular, the load of prev->state in finish_task_switch() must
- * happen before this.
- *
- * Pairs with the smp_cond_load_acquire() in try_to_wake_up().
- */
- smp_store_release(&prev->on_cpu, 0);
- #endif
- }
- static inline void
- prepare_lock_switch(struct rq *rq, struct task_struct *next, struct rq_flags *rf)
- {
- /*
- * 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:
- */
- rq_unpin_lock(rq, rf);
- spin_release(&rq->lock.dep_map, _THIS_IP_);
- #ifdef CONFIG_DEBUG_SPINLOCK
- /* this is a valid case when another task releases the spinlock */
- rq->lock.owner = next;
- #endif
- }
- static inline void finish_lock_switch(struct rq *rq)
- {
- /*
- * If we are tracking spinlock dependencies then we have to
- * fix up the runqueue lock - which gets 'carried over' from
- * prev into current:
- */
- spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
- raw_spin_unlock_irq(&rq->lock);
- }
- /*
- * NOP if the arch has not defined these:
- */
- #ifndef prepare_arch_switch
- # define prepare_arch_switch(next) do { } while (0)
- #endif
- #ifndef finish_arch_post_lock_switch
- # define finish_arch_post_lock_switch() do { } while (0)
- #endif
- /**
- * 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)
- {
- kcov_prepare_switch(prev);
- sched_info_switch(rq, prev, next);
- perf_event_task_sched_out(prev, next);
- rseq_preempt(prev);
- fire_sched_out_preempt_notifiers(prev, next);
- prepare_task(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;
- /*
- * The previous task will have left us with a preempt_count of 2
- * because it left us after:
- *
- * schedule()
- * preempt_disable(); // 1
- * __schedule()
- * raw_spin_lock_irq(&rq->lock) // 2
- *
- * Also, see FORK_PREEMPT_COUNT.
- */
- if (WARN_ONCE(preempt_count() != 2*PREEMPT_DISABLE_OFFSET,
- "corrupted preempt_count: %s/%d/0x%x\n",
- current->comm, current->pid, preempt_count()))
- preempt_count_set(FORK_PREEMPT_COUNT);
- 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_task), 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;
- vtime_task_switch(prev);
- perf_event_task_sched_in(prev, current);
- finish_task(prev);
- finish_lock_switch(rq);
- finish_arch_post_lock_switch();
- kcov_finish_switch(current);
- fire_sched_in_preempt_notifiers(current);
- /*
- * When switching through a kernel thread, the loop in
- * membarrier_{private,global}_expedited() may have observed that
- * kernel thread and not issued an IPI. It is therefore possible to
- * schedule between user->kernel->user threads without passing though
- * switch_mm(). Membarrier requires a barrier after storing to
- * rq->curr, before returning to userspace, so provide them here:
- *
- * - a full memory barrier for {PRIVATE,GLOBAL}_EXPEDITED, implicitly
- * provided by mmdrop(),
- * - a sync_core for SYNC_CORE.
- */
- if (mm) {
- membarrier_mm_sync_core_before_usermode(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);
- trace_android_rvh_flush_task(prev);
- /* Task is done with its stack. */
- put_task_stack(prev);
- put_task_struct_rcu_user(prev);
- }
- tick_nohz_task_switch();
- return rq;
- }
- #ifdef CONFIG_SMP
- /* rq->lock is NOT held, but preemption is disabled */
- static void __balance_callback(struct rq *rq)
- {
- struct callback_head *head, *next;
- void (*func)(struct rq *rq);
- unsigned long flags;
- raw_spin_lock_irqsave(&rq->lock, flags);
- head = rq->balance_callback;
- rq->balance_callback = NULL;
- while (head) {
- func = (void (*)(struct rq *))head->func;
- next = head->next;
- head->next = NULL;
- head = next;
- func(rq);
- }
- raw_spin_unlock_irqrestore(&rq->lock, flags);
- }
- static inline void balance_callback(struct rq *rq)
- {
- if (unlikely(rq->balance_callback))
- __balance_callback(rq);
- }
- #else
- static inline void balance_callback(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;
- /*
- * New tasks start with FORK_PREEMPT_COUNT, see there and
- * finish_task_switch() for details.
- *
- * finish_task_switch() will drop rq->lock() and lower preempt_count
- * and the preempt_enable() will end up enabling preemption (on
- * PREEMPT_COUNT kernels).
- */
- rq = finish_task_switch(prev);
- balance_callback(rq);
- preempt_enable();
- if (current->set_child_tid)
- put_user(task_pid_vnr(current), current->set_child_tid);
- calculate_sigpending();
- }
- /*
- * context_switch - switch to the new MM and the new thread's register state.
- */
- static __always_inline struct rq *
- context_switch(struct rq *rq, struct task_struct *prev,
- struct task_struct *next, struct rq_flags *rf)
- {
- prepare_task_switch(rq, prev, next);
- /*
- * 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);
- /*
- * kernel -> kernel lazy + transfer active
- * user -> kernel lazy + mmgrab() active
- *
- * kernel -> user switch + mmdrop() active
- * user -> user switch
- */
- if (!next->mm) { // to kernel
- enter_lazy_tlb(prev->active_mm, next);
- next->active_mm = prev->active_mm;
- if (prev->mm) // from user
- mmgrab(prev->active_mm);
- else
- prev->active_mm = NULL;
- } else { // to user
- membarrier_switch_mm(rq, prev->active_mm, next->mm);
- /*
- * sys_membarrier() requires an smp_mb() between setting
- * rq->curr / membarrier_switch_mm() and returning to userspace.
- *
- * The below provides this either through switch_mm(), or in
- * case 'prev->active_mm == next->mm' through
- * finish_task_switch()'s mmdrop().
- */
- switch_mm_irqs_off(prev->active_mm, next->mm, next);
- if (!prev->mm) { // from kernel
- /* will mmdrop() in finish_task_switch(). */
- rq->prev_mm = prev->active_mm;
- prev->active_mm = NULL;
- }
- }
- rq->clock_update_flags &= ~(RQCF_ACT_SKIP|RQCF_REQ_SKIP);
- prepare_lock_switch(rq, next, rf);
- /* 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-preemptible 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;
- }
- /*
- * Consumers of these two interfaces, like for example the cpuidle menu
- * governor, are using nonsensical data. Preferring shallow idle state selection
- * for a CPU that has IO-wait which might not even end up running the task when
- * it does become runnable.
- */
- unsigned long nr_iowait_cpu(int cpu)
- {
- return atomic_read(&cpu_rq(cpu)->nr_iowait);
- }
- /*
- * IO-wait accounting, and how its mostly bollocks (on SMP).
- *
- * The idea behind IO-wait account is to account the idle time that we could
- * have spend running if it were not for IO. That is, if we were to improve the
- * storage performance, we'd have a proportional reduction in IO-wait time.
- *
- * This all works nicely on UP, where, when a task blocks on IO, we account
- * idle time as IO-wait, because if the storage were faster, it could've been
- * running and we'd not be idle.
- *
- * This has been extended to SMP, by doing the same for each CPU. This however
- * is broken.
- *
- * Imagine for instance the case where two tasks block on one CPU, only the one
- * CPU will have IO-wait accounted, while the other has regular idle. Even
- * though, if the storage were faster, both could've ran at the same time,
- * utilising both CPUs.
- *
- * This means, that when looking globally, the current IO-wait accounting on
- * SMP is a lower bound, by reason of under accounting.
- *
- * Worse, since the numbers are provided per CPU, they are sometimes
- * interpreted per CPU, and that is nonsensical. A blocked task isn't strictly
- * associated with any one particular CPU, it can wake to another CPU than it
- * blocked on. This means the per CPU IO-wait number is meaningless.
- *
- * Task CPU affinities can make all that even more 'interesting'.
- */
- unsigned long nr_iowait(void)
- {
- unsigned long i, sum = 0;
- for_each_possible_cpu(i)
- sum += nr_iowait_cpu(i);
- return sum;
- }
- #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;
- bool cond = false;
- trace_android_rvh_sched_exec(&cond);
- if (cond)
- return;
- 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);
- /*
- * The function fair_sched_class.update_curr accesses the struct curr
- * and its field curr->exec_start; when called from task_sched_runtime(),
- * we observe a high rate of cache misses in practice.
- * Prefetching this data results in improved performance.
- */
- static inline void prefetch_curr_exec_start(struct task_struct *p)
- {
- #ifdef CONFIG_FAIR_GROUP_SCHED
- struct sched_entity *curr = (&p->se)->cfs_rq->curr;
- #else
- struct sched_entity *curr = (&task_rq(p)->cfs)->curr;
- #endif
- prefetch(curr);
- prefetch(&curr->exec_start);
- }
- /*
- * 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)
- {
- struct rq_flags rf;
- struct rq *rq;
- u64 ns;
- #if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
- /*
- * 64-bit doesn't need locks to atomically read a 64-bit 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, &rf);
- /*
- * 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)) {
- prefetch_curr_exec_start(p);
- update_rq_clock(rq);
- p->sched_class->update_curr(rq);
- }
- ns = p->se.sum_exec_runtime;
- task_rq_unlock(rq, p, &rf);
- return ns;
- }
- EXPORT_SYMBOL_GPL(task_sched_runtime);
- /*
- * 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;
- struct rq_flags rf;
- unsigned long thermal_pressure;
- arch_scale_freq_tick();
- sched_clock_tick();
- rq_lock(rq, &rf);
- trace_android_rvh_tick_entry(rq);
- update_rq_clock(rq);
- thermal_pressure = arch_scale_thermal_pressure(cpu_of(rq));
- update_thermal_load_avg(rq_clock_thermal(rq), rq, thermal_pressure);
- curr->sched_class->task_tick(rq, curr, 0);
- calc_global_load_tick(rq);
- psi_task_tick(rq);
- rq_unlock(rq, &rf);
- perf_event_task_tick();
- #ifdef CONFIG_SMP
- rq->idle_balance = idle_cpu(cpu);
- trigger_load_balance(rq);
- #endif
- trace_android_vh_scheduler_tick(rq);
- }
- #ifdef CONFIG_NO_HZ_FULL
- struct tick_work {
- int cpu;
- atomic_t state;
- struct delayed_work work;
- };
- /* Values for ->state, see diagram below. */
- #define TICK_SCHED_REMOTE_OFFLINE 0
- #define TICK_SCHED_REMOTE_OFFLINING 1
- #define TICK_SCHED_REMOTE_RUNNING 2
- /*
- * State diagram for ->state:
- *
- *
- * TICK_SCHED_REMOTE_OFFLINE
- * | ^
- * | |
- * | | sched_tick_remote()
- * | |
- * | |
- * +--TICK_SCHED_REMOTE_OFFLINING
- * | ^
- * | |
- * sched_tick_start() | | sched_tick_stop()
- * | |
- * V |
- * TICK_SCHED_REMOTE_RUNNING
- *
- *
- * Other transitions get WARN_ON_ONCE(), except that sched_tick_remote()
- * and sched_tick_start() are happy to leave the state in RUNNING.
- */
- static struct tick_work __percpu *tick_work_cpu;
- static void sched_tick_remote(struct work_struct *work)
- {
- struct delayed_work *dwork = to_delayed_work(work);
- struct tick_work *twork = container_of(dwork, struct tick_work, work);
- int cpu = twork->cpu;
- struct rq *rq = cpu_rq(cpu);
- struct task_struct *curr;
- struct rq_flags rf;
- u64 delta;
- int os;
- /*
- * Handle the tick only if it appears the remote CPU is running in full
- * dynticks mode. The check is racy by nature, but missing a tick or
- * having one too much is no big deal because the scheduler tick updates
- * statistics and checks timeslices in a time-independent way, regardless
- * of when exactly it is running.
- */
- if (!tick_nohz_tick_stopped_cpu(cpu))
- goto out_requeue;
- rq_lock_irq(rq, &rf);
- curr = rq->curr;
- if (cpu_is_offline(cpu))
- goto out_unlock;
- update_rq_clock(rq);
- if (!is_idle_task(curr)) {
- /*
- * Make sure the next tick runs within a reasonable
- * amount of time.
- */
- delta = rq_clock_task(rq) - curr->se.exec_start;
- WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3);
- }
- curr->sched_class->task_tick(rq, curr, 0);
- calc_load_nohz_remote(rq);
- out_unlock:
- rq_unlock_irq(rq, &rf);
- out_requeue:
- /*
- * Run the remote tick once per second (1Hz). This arbitrary
- * frequency is large enough to avoid overload but short enough
- * to keep scheduler internal stats reasonably up to date. But
- * first update state to reflect hotplug activity if required.
- */
- os = atomic_fetch_add_unless(&twork->state, -1, TICK_SCHED_REMOTE_RUNNING);
- WARN_ON_ONCE(os == TICK_SCHED_REMOTE_OFFLINE);
- if (os == TICK_SCHED_REMOTE_RUNNING)
- queue_delayed_work(system_unbound_wq, dwork, HZ);
- }
- static void sched_tick_start(int cpu)
- {
- int os;
- struct tick_work *twork;
- if (housekeeping_cpu(cpu, HK_FLAG_TICK))
- return;
- WARN_ON_ONCE(!tick_work_cpu);
- twork = per_cpu_ptr(tick_work_cpu, cpu);
- os = atomic_xchg(&twork->state, TICK_SCHED_REMOTE_RUNNING);
- WARN_ON_ONCE(os == TICK_SCHED_REMOTE_RUNNING);
- if (os == TICK_SCHED_REMOTE_OFFLINE) {
- twork->cpu = cpu;
- INIT_DELAYED_WORK(&twork->work, sched_tick_remote);
- queue_delayed_work(system_unbound_wq, &twork->work, HZ);
- }
- }
- #ifdef CONFIG_HOTPLUG_CPU
- static void sched_tick_stop(int cpu)
- {
- struct tick_work *twork;
- int os;
- if (housekeeping_cpu(cpu, HK_FLAG_TICK))
- return;
- WARN_ON_ONCE(!tick_work_cpu);
- twork = per_cpu_ptr(tick_work_cpu, cpu);
- /* There cannot be competing actions, but don't rely on stop-machine. */
- os = atomic_xchg(&twork->state, TICK_SCHED_REMOTE_OFFLINING);
- WARN_ON_ONCE(os != TICK_SCHED_REMOTE_RUNNING);
- /* Don't cancel, as this would mess up the state machine. */
- }
- #endif /* CONFIG_HOTPLUG_CPU */
- int __init sched_tick_offload_init(void)
- {
- tick_work_cpu = alloc_percpu(struct tick_work);
- BUG_ON(!tick_work_cpu);
- return 0;
- }
- #else /* !CONFIG_NO_HZ_FULL */
- static inline void sched_tick_start(int cpu) { }
- static inline void sched_tick_stop(int cpu) { }
- #endif
- #if defined(CONFIG_PREEMPTION) && (defined(CONFIG_DEBUG_PREEMPT) || \
- defined(CONFIG_TRACE_PREEMPT_TOGGLE))
- /*
- * If the value passed in is equal to the current preempt count
- * then we just disabled preemption. Start timing the latency.
- */
- static inline void preempt_latency_start(int val)
- {
- if (preempt_count() == val) {
- unsigned long ip = get_lock_parent_ip();
- #ifdef CONFIG_DEBUG_PREEMPT
- current->preempt_disable_ip = ip;
- #endif
- trace_preempt_off(CALLER_ADDR0, ip);
- }
- }
- 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
- preempt_latency_start(val);
- }
- EXPORT_SYMBOL(preempt_count_add);
- NOKPROBE_SYMBOL(preempt_count_add);
- /*
- * If the value passed in equals to the current preempt count
- * then we just enabled preemption. Stop timing the latency.
- */
- static inline void preempt_latency_stop(int val)
- {
- if (preempt_count() == val)
- trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip());
- }
- 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
- preempt_latency_stop(val);
- __preempt_count_sub(val);
- }
- EXPORT_SYMBOL(preempt_count_sub);
- NOKPROBE_SYMBOL(preempt_count_sub);
- #else
- static inline void preempt_latency_start(int val) { }
- static inline void preempt_latency_stop(int val) { }
- #endif
- static inline unsigned long get_preempt_disable_ip(struct task_struct *p)
- {
- #ifdef CONFIG_DEBUG_PREEMPT
- return p->preempt_disable_ip;
- #else
- return 0;
- #endif
- }
- /*
- * Print scheduling while atomic bug:
- */
- static noinline void __schedule_bug(struct task_struct *prev)
- {
- /* Save this before calling printk(), since that will clobber it */
- unsigned long preempt_disable_ip = get_preempt_disable_ip(current);
- 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);
- if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
- && in_atomic_preempt_off()) {
- pr_err("Preemption disabled at:");
- print_ip_sym(KERN_ERR, preempt_disable_ip);
- }
- if (panic_on_warn)
- panic("scheduling while atomic\n");
- trace_android_rvh_schedule_bug(prev);
- 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, bool preempt)
- {
- #ifdef CONFIG_SCHED_STACK_END_CHECK
- if (task_stack_end_corrupted(prev))
- panic("corrupted stack end detected inside scheduler\n");
- if (task_scs_end_corrupted(prev))
- panic("corrupted shadow stack detected inside scheduler\n");
- #endif
- #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
- if (!preempt && prev->state && prev->non_block_count) {
- printk(KERN_ERR "BUG: scheduling in a non-blocking section: %s/%d/%i\n",
- prev->comm, prev->pid, prev->non_block_count);
- dump_stack();
- add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
- }
- #endif
- if (unlikely(in_atomic_preempt_off())) {
- __schedule_bug(prev);
- preempt_count_set(PREEMPT_DISABLED);
- }
- rcu_sleep_check();
- profile_hit(SCHED_PROFILING, __builtin_return_address(0));
- schedstat_inc(this_rq()->sched_count);
- }
- static void put_prev_task_balance(struct rq *rq, struct task_struct *prev,
- struct rq_flags *rf)
- {
- #ifdef CONFIG_SMP
- const struct sched_class *class;
- /*
- * We must do the balancing pass before put_prev_task(), such
- * that when we release the rq->lock the task is in the same
- * state as before we took rq->lock.
- *
- * We can terminate the balance pass as soon as we know there is
- * a runnable task of @class priority or higher.
- */
- for_class_range(class, prev->sched_class, &idle_sched_class) {
- if (class->balance(rq, prev, rf))
- break;
- }
- #endif
- put_prev_task(rq, prev);
- }
- /*
- * Pick up the highest-prio task:
- */
- static inline struct task_struct *
- pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
- {
- const struct sched_class *class;
- struct task_struct *p;
- /*
- * Optimization: we know that if all tasks are in the fair class we can
- * call that function directly, but only if the @prev task wasn't of a
- * higher scheduling class, because otherwise those loose the
- * opportunity to pull in more work from other CPUs.
- */
- if (likely(prev->sched_class <= &fair_sched_class &&
- rq->nr_running == rq->cfs.h_nr_running)) {
- p = pick_next_task_fair(rq, prev, rf);
- if (unlikely(p == RETRY_TASK))
- goto restart;
- /* Assumes fair_sched_class->next == idle_sched_class */
- if (!p) {
- put_prev_task(rq, prev);
- p = pick_next_task_idle(rq);
- }
- return p;
- }
- restart:
- put_prev_task_balance(rq, prev, rf);
- for_each_class(class) {
- p = class->pick_next_task(rq);
- if (p)
- return p;
- }
- /* The idle class should always have a runnable task: */
- BUG();
- }
- /*
- * __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_PREEMPTION=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_PREEMPTION 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: must be called with preemption disabled!
- */
- static void __sched notrace __schedule(bool preempt)
- {
- struct task_struct *prev, *next;
- unsigned long *switch_count;
- unsigned long prev_state;
- struct rq_flags rf;
- struct rq *rq;
- int cpu;
- cpu = smp_processor_id();
- rq = cpu_rq(cpu);
- prev = rq->curr;
- schedule_debug(prev, preempt);
- if (sched_feat(HRTICK))
- hrtick_clear(rq);
- local_irq_disable();
- rcu_note_context_switch(preempt);
- /*
- * 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():
- *
- * __set_current_state(@state) signal_wake_up()
- * schedule() set_tsk_thread_flag(p, TIF_SIGPENDING)
- * wake_up_state(p, state)
- * LOCK rq->lock LOCK p->pi_state
- * smp_mb__after_spinlock() smp_mb__after_spinlock()
- * if (signal_pending_state()) if (p->state & @state)
- *
- * Also, the membarrier system call requires a full memory barrier
- * after coming from user-space, before storing to rq->curr.
- */
- rq_lock(rq, &rf);
- smp_mb__after_spinlock();
- /* Promote REQ to ACT */
- rq->clock_update_flags <<= 1;
- update_rq_clock(rq);
- switch_count = &prev->nivcsw;
- /*
- * We must load prev->state once (task_struct::state is volatile), such
- * that:
- *
- * - we form a control dependency vs deactivate_task() below.
- * - ptrace_{,un}freeze_traced() can change ->state underneath us.
- */
- prev_state = prev->state;
- if (!preempt && prev_state) {
- if (signal_pending_state(prev_state, prev)) {
- prev->state = TASK_RUNNING;
- } else {
- prev->sched_contributes_to_load =
- (prev_state & TASK_UNINTERRUPTIBLE) &&
- !(prev_state & TASK_NOLOAD) &&
- !(prev->flags & PF_FROZEN);
- if (prev->sched_contributes_to_load)
- rq->nr_uninterruptible++;
- /*
- * __schedule() ttwu()
- * prev_state = prev->state; if (p->on_rq && ...)
- * if (prev_state) goto out;
- * p->on_rq = 0; smp_acquire__after_ctrl_dep();
- * p->state = TASK_WAKING
- *
- * Where __schedule() and ttwu() have matching control dependencies.
- *
- * After this, schedule() must not care about p->state any more.
- */
- deactivate_task(rq, prev, DEQUEUE_SLEEP | DEQUEUE_NOCLOCK);
- if (prev->in_iowait) {
- atomic_inc(&rq->nr_iowait);
- delayacct_blkio_start();
- }
- }
- switch_count = &prev->nvcsw;
- }
- next = pick_next_task(rq, prev, &rf);
- clear_tsk_need_resched(prev);
- clear_preempt_need_resched();
- trace_android_rvh_schedule(prev, next, rq);
- if (likely(prev != next)) {
- rq->nr_switches++;
- /*
- * RCU users of rcu_dereference(rq->curr) may not see
- * changes to task_struct made by pick_next_task().
- */
- RCU_INIT_POINTER(rq->curr, next);
- /*
- * The membarrier system call requires each architecture
- * to have a full memory barrier after updating
- * rq->curr, before returning to user-space.
- *
- * Here are the schemes providing that barrier on the
- * various architectures:
- * - mm ? switch_mm() : mmdrop() for x86, s390, sparc, PowerPC.
- * switch_mm() rely on membarrier_arch_switch_mm() on PowerPC.
- * - finish_lock_switch() for weakly-ordered
- * architectures where spin_unlock is a full barrier,
- * - switch_to() for arm64 (weakly-ordered, spin_unlock
- * is a RELEASE barrier),
- */
- ++*switch_count;
- psi_sched_switch(prev, next, !task_on_rq_queued(prev));
- trace_sched_switch(preempt, prev, next);
- /* Also unlocks the rq: */
- rq = context_switch(rq, prev, next, &rf);
- } else {
- rq->clock_update_flags &= ~(RQCF_ACT_SKIP|RQCF_REQ_SKIP);
- rq_unlock_irq(rq, &rf);
- }
- balance_callback(rq);
- }
- void __noreturn do_task_dead(void)
- {
- /* Causes final put_task_struct in finish_task_switch(): */
- set_special_state(TASK_DEAD);
- /* Tell freezer to ignore us: */
- current->flags |= PF_NOFREEZE;
- __schedule(false);
- BUG();
- /* Avoid "noreturn function does return" - but don't continue if BUG() is a NOP: */
- for (;;)
- cpu_relax();
- }
- static inline void sched_submit_work(struct task_struct *tsk)
- {
- unsigned int task_flags;
- if (!tsk->state)
- return;
- task_flags = tsk->flags;
- /*
- * If a worker went to sleep, notify and ask workqueue whether
- * it wants to wake up a task to maintain concurrency.
- * As this function is called inside the schedule() context,
- * we disable preemption to avoid it calling schedule() again
- * in the possible wakeup of a kworker and because wq_worker_sleeping()
- * requires it.
- */
- if (task_flags & (PF_WQ_WORKER | PF_IO_WORKER)) {
- preempt_disable();
- if (task_flags & PF_WQ_WORKER)
- wq_worker_sleeping(tsk);
- else
- io_wq_worker_sleeping(tsk);
- preempt_enable_no_resched();
- }
- if (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);
- }
- static void sched_update_worker(struct task_struct *tsk)
- {
- if (tsk->flags & (PF_WQ_WORKER | PF_IO_WORKER)) {
- if (tsk->flags & PF_WQ_WORKER)
- wq_worker_running(tsk);
- else
- io_wq_worker_running(tsk);
- }
- }
- asmlinkage __visible void __sched schedule(void)
- {
- struct task_struct *tsk = current;
- sched_submit_work(tsk);
- do {
- preempt_disable();
- __schedule(false);
- sched_preempt_enable_no_resched();
- } while (need_resched());
- sched_update_worker(tsk);
- }
- EXPORT_SYMBOL(schedule);
- /*
- * synchronize_rcu_tasks() makes sure that no task is stuck in preempted
- * state (have scheduled out non-voluntarily) by making sure that all
- * tasks have either left the run queue or have gone into user space.
- * As idle tasks do not do either, they must not ever be preempted
- * (schedule out non-voluntarily).
- *
- * schedule_idle() is similar to schedule_preempt_disable() except that it
- * never enables preemption because it does not call sched_submit_work().
- */
- void __sched schedule_idle(void)
- {
- /*
- * As this skips calling sched_submit_work(), which the idle task does
- * regardless because that function is a nop when the task is in a
- * TASK_RUNNING state, make sure this isn't used someplace that the
- * current task can be in any other state. Note, idle is always in the
- * TASK_RUNNING state.
- */
- WARN_ON_ONCE(current->state);
- do {
- __schedule(false);
- } while (need_resched());
- }
- #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 {
- /*
- * Because the function tracer can trace preempt_count_sub()
- * and it also uses preempt_enable/disable_notrace(), if
- * NEED_RESCHED is set, the preempt_enable_notrace() called
- * by the function tracer will call this function again and
- * cause infinite recursion.
- *
- * Preemption must be disabled here before the function
- * tracer can trace. Break up preempt_disable() into two
- * calls. One to disable preemption without fear of being
- * traced. The other to still record the preemption latency,
- * which can also be traced by the function tracer.
- */
- preempt_disable_notrace();
- preempt_latency_start(1);
- __schedule(true);
- preempt_latency_stop(1);
- preempt_enable_no_resched_notrace();
- /*
- * Check again in case we missed a preemption opportunity
- * between schedule and now.
- */
- } while (need_resched());
- }
- #ifdef CONFIG_PREEMPTION
- /*
- * This is the entry point to schedule() from in-kernel preemption
- * off of preempt_enable.
- */
- 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);
- /**
- * preempt_schedule_notrace - 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_notrace(void)
- {
- enum ctx_state prev_ctx;
- if (likely(!preemptible()))
- return;
- do {
- /*
- * Because the function tracer can trace preempt_count_sub()
- * and it also uses preempt_enable/disable_notrace(), if
- * NEED_RESCHED is set, the preempt_enable_notrace() called
- * by the function tracer will call this function again and
- * cause infinite recursion.
- *
- * Preemption must be disabled here before the function
- * tracer can trace. Break up preempt_disable() into two
- * calls. One to disable preemption without fear of being
- * traced. The other to still record the preemption latency,
- * which can also be traced by the function tracer.
- */
- preempt_disable_notrace();
- preempt_latency_start(1);
- /*
- * 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(true);
- exception_exit(prev_ctx);
- preempt_latency_stop(1);
- preempt_enable_no_resched_notrace();
- } while (need_resched());
- }
- EXPORT_SYMBOL_GPL(preempt_schedule_notrace);
- #endif /* CONFIG_PREEMPTION */
- /*
- * 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_disable();
- local_irq_enable();
- __schedule(true);
- local_irq_disable();
- sched_preempt_enable_no_resched();
- } while (need_resched());
- exception_exit(prev_state);
- }
- int default_wake_function(wait_queue_entry_t *curr, unsigned mode, int wake_flags,
- void *key)
- {
- WARN_ON_ONCE(IS_ENABLED(CONFIG_SCHED_DEBUG) && wake_flags & ~(WF_SYNC | WF_ANDROID_VENDOR));
- return try_to_wake_up(curr->private, mode, wake_flags);
- }
- EXPORT_SYMBOL(default_wake_function);
- static void __setscheduler_prio(struct task_struct *p, int prio)
- {
- if (dl_prio(prio))
- p->sched_class = &dl_sched_class;
- else if (rt_prio(prio))
- p->sched_class = &rt_sched_class;
- else
- p->sched_class = &fair_sched_class;
- p->prio = prio;
- }
- #ifdef CONFIG_RT_MUTEXES
- static inline int __rt_effective_prio(struct task_struct *pi_task, int prio)
- {
- if (pi_task)
- prio = min(prio, pi_task->prio);
- return prio;
- }
- static inline int rt_effective_prio(struct task_struct *p, int prio)
- {
- struct task_struct *pi_task = rt_mutex_get_top_task(p);
- return __rt_effective_prio(pi_task, prio);
- }
- /*
- * rt_mutex_setprio - set the current priority of a task
- * @p: task to boost
- * @pi_task: donor task
- *
- * 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, struct task_struct *pi_task)
- {
- int prio, oldprio, queued, running, queue_flag =
- DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK;
- const struct sched_class *prev_class;
- struct rq_flags rf;
- struct rq *rq;
- trace_android_rvh_rtmutex_prepare_setprio(p, pi_task);
- /* XXX used to be waiter->prio, not waiter->task->prio */
- prio = __rt_effective_prio(pi_task, p->normal_prio);
- /*
- * If nothing changed; bail early.
- */
- if (p->pi_top_task == pi_task && prio == p->prio && !dl_prio(prio))
- return;
- rq = __task_rq_lock(p, &rf);
- update_rq_clock(rq);
- /*
- * Set under pi_lock && rq->lock, such that the value can be used under
- * either lock.
- *
- * Note that there is loads of tricky to make this pointer cache work
- * right. rt_mutex_slowunlock()+rt_mutex_postunlock() work together to
- * ensure a task is de-boosted (pi_task is set to NULL) before the
- * task is allowed to run again (and can exit). This ensures the pointer
- * points to a blocked task -- which guaratees the task is present.
- */
- p->pi_top_task = pi_task;
- /*
- * For FIFO/RR we only need to set prio, if that matches we're done.
- */
- if (prio == p->prio && !dl_prio(prio))
- goto out_unlock;
- /*
- * 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, pi_task);
- oldprio = p->prio;
- if (oldprio == prio)
- queue_flag &= ~DEQUEUE_MOVE;
- prev_class = p->sched_class;
- queued = task_on_rq_queued(p);
- running = task_current(rq, p);
- if (queued)
- dequeue_task(rq, p, queue_flag);
- 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)) {
- if (!dl_prio(p->normal_prio) ||
- (pi_task && dl_prio(pi_task->prio) &&
- dl_entity_preempt(&pi_task->dl, &p->dl))) {
- p->dl.pi_se = pi_task->dl.pi_se;
- queue_flag |= ENQUEUE_REPLENISH;
- } else {
- p->dl.pi_se = &p->dl;
- }
- } else if (rt_prio(prio)) {
- if (dl_prio(oldprio))
- p->dl.pi_se = &p->dl;
- if (oldprio < prio)
- queue_flag |= ENQUEUE_HEAD;
- } else {
- if (dl_prio(oldprio))
- p->dl.pi_se = &p->dl;
- if (rt_prio(oldprio))
- p->rt.timeout = 0;
- }
- __setscheduler_prio(p, prio);
- if (queued)
- enqueue_task(rq, p, queue_flag);
- if (running)
- set_next_task(rq, p);
- check_class_changed(rq, p, prev_class, oldprio);
- out_unlock:
- /* Avoid rq from going away on us: */
- preempt_disable();
- __task_rq_unlock(rq, &rf);
- balance_callback(rq);
- preempt_enable();
- }
- #else
- static inline int rt_effective_prio(struct task_struct *p, int prio)
- {
- return prio;
- }
- #endif
- void set_user_nice(struct task_struct *p, long nice)
- {
- bool queued, running, allowed = false;
- int old_prio;
- struct rq_flags rf;
- struct rq *rq;
- trace_android_rvh_set_user_nice(p, &nice, &allowed);
- if ((task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE) && !allowed)
- 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, &rf);
- update_rq_clock(rq);
- /*
- * 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);
- running = task_current(rq, p);
- if (queued)
- dequeue_task(rq, p, DEQUEUE_SAVE | DEQUEUE_NOCLOCK);
- if (running)
- put_prev_task(rq, p);
- p->static_prio = NICE_TO_PRIO(nice);
- set_load_weight(p, true);
- old_prio = p->prio;
- p->prio = effective_prio(p);
- if (queued)
- enqueue_task(rq, p, ENQUEUE_RESTORE | ENQUEUE_NOCLOCK);
- if (running)
- set_next_task(rq, p);
- /*
- * If the task increased its priority or is running and
- * lowered its priority, then reschedule its CPU:
- */
- p->sched_class->prio_changed(rq, p, old_prio);
- out_unlock:
- task_rq_unlock(rq, p, &rf);
- }
- 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 (rq->ttwu_pending)
- return 0;
- #endif
- return 1;
- }
- /**
- * available_idle_cpu - is a given CPU idle for enqueuing work.
- * @cpu: the CPU in question.
- *
- * Return: 1 if the CPU is currently idle. 0 otherwise.
- */
- int available_idle_cpu(int cpu)
- {
- if (!idle_cpu(cpu))
- return 0;
- if (vcpu_is_preempted(cpu))
- return 0;
- return 1;
- }
- EXPORT_SYMBOL_GPL(available_idle_cpu);
- /**
- * 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;
- }
- /*
- * 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, 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 int __sched_setscheduler(struct task_struct *p,
- const struct sched_attr *attr,
- bool user, bool pi)
- {
- int oldpolicy = -1, policy = attr->sched_policy;
- int retval, oldprio, newprio, queued, running;
- const struct sched_class *prev_class;
- struct rq_flags rf;
- int reset_on_fork;
- int queue_flags = DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK;
- struct rq *rq;
- /* The pi code expects interrupts enabled */
- BUG_ON(pi && 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 (!valid_policy(policy))
- return -EINVAL;
- }
- if (attr->sched_flags & ~(SCHED_FLAG_ALL | SCHED_FLAG_SUGOV))
- 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 (task_has_idle_policy(p) && !idle_policy(policy)) {
- 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;
- /* Can't change util-clamps */
- if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP)
- return -EPERM;
- }
- if (user) {
- if (attr->sched_flags & SCHED_FLAG_SUGOV)
- return -EINVAL;
- retval = security_task_setscheduler(p);
- if (retval)
- return retval;
- }
- /* Update task specific "requested" clamps */
- if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP) {
- retval = uclamp_validate(p, attr);
- 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, &rf);
- update_rq_clock(rq);
- /*
- * Changing the policy of the stop threads its a very bad idea:
- */
- if (p == rq->stop) {
- retval = -EINVAL;
- goto unlock;
- }
- /*
- * 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;
- if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP)
- goto change;
- p->sched_reset_on_fork = reset_on_fork;
- retval = 0;
- goto unlock;
- }
- 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))) {
- retval = -EPERM;
- goto unlock;
- }
- #endif
- #ifdef CONFIG_SMP
- if (dl_bandwidth_enabled() && dl_policy(policy) &&
- !(attr->sched_flags & SCHED_FLAG_SUGOV)) {
- 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_ptr) ||
- rq->rd->dl_bw.bw == 0) {
- retval = -EPERM;
- goto unlock;
- }
- }
- #endif
- }
- /* Re-check policy now with rq lock held: */
- if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
- policy = oldpolicy = -1;
- task_rq_unlock(rq, p, &rf);
- 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)) && sched_dl_overflow(p, policy, attr)) {
- retval = -EBUSY;
- goto unlock;
- }
- p->sched_reset_on_fork = reset_on_fork;
- oldprio = p->prio;
- newprio = __normal_prio(policy, attr->sched_priority, attr->sched_nice);
- if (pi) {
- /*
- * 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.
- */
- newprio = rt_effective_prio(p, newprio);
- if (newprio == oldprio)
- queue_flags &= ~DEQUEUE_MOVE;
- }
- queued = task_on_rq_queued(p);
- running = task_current(rq, p);
- if (queued)
- dequeue_task(rq, p, queue_flags);
- if (running)
- put_prev_task(rq, p);
- prev_class = p->sched_class;
- if (!(attr->sched_flags & SCHED_FLAG_KEEP_PARAMS)) {
- __setscheduler_params(p, attr);
- __setscheduler_prio(p, newprio);
- trace_android_rvh_setscheduler(p);
- }
- __setscheduler_uclamp(p, attr);
- if (queued) {
- /*
- * We enqueue to tail when the priority of a task is
- * increased (user space view).
- */
- if (oldprio < p->prio)
- queue_flags |= ENQUEUE_HEAD;
- enqueue_task(rq, p, queue_flags);
- }
- if (running)
- set_next_task(rq, p);
- check_class_changed(rq, p, prev_class, oldprio);
- /* Avoid rq from going away on us: */
- preempt_disable();
- task_rq_unlock(rq, p, &rf);
- if (pi)
- rt_mutex_adjust_pi(p);
- /* Run balance callbacks after we've adjusted the PI chain: */
- balance_callback(rq);
- preempt_enable();
- return 0;
- unlock:
- task_rq_unlock(rq, p, &rf);
- return retval;
- }
- 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, true);
- }
- /**
- * 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.
- *
- * Use sched_set_fifo(), read its comment.
- *
- * 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, true);
- }
- EXPORT_SYMBOL_GPL(sched_setattr);
- int sched_setattr_nocheck(struct task_struct *p, const struct sched_attr *attr)
- {
- return __sched_setscheduler(p, attr, false, true);
- }
- EXPORT_SYMBOL_GPL(sched_setattr_nocheck);
- /**
- * 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);
- }
- EXPORT_SYMBOL_GPL(sched_setscheduler_nocheck);
- /*
- * SCHED_FIFO is a broken scheduler model; that is, it is fundamentally
- * incapable of resource management, which is the one thing an OS really should
- * be doing.
- *
- * This is of course the reason it is limited to privileged users only.
- *
- * Worse still; it is fundamentally impossible to compose static priority
- * workloads. You cannot take two correctly working static prio workloads
- * and smash them together and still expect them to work.
- *
- * For this reason 'all' FIFO tasks the kernel creates are basically at:
- *
- * MAX_RT_PRIO / 2
- *
- * The administrator _MUST_ configure the system, the kernel simply doesn't
- * know enough information to make a sensible choice.
- */
- void sched_set_fifo(struct task_struct *p)
- {
- struct sched_param sp = { .sched_priority = MAX_RT_PRIO / 2 };
- WARN_ON_ONCE(sched_setscheduler_nocheck(p, SCHED_FIFO, &sp) != 0);
- }
- EXPORT_SYMBOL_GPL(sched_set_fifo);
- /*
- * For when you don't much care about FIFO, but want to be above SCHED_NORMAL.
- */
- void sched_set_fifo_low(struct task_struct *p)
- {
- struct sched_param sp = { .sched_priority = 1 };
- WARN_ON_ONCE(sched_setscheduler_nocheck(p, SCHED_FIFO, &sp) != 0);
- }
- EXPORT_SYMBOL_GPL(sched_set_fifo_low);
- void sched_set_normal(struct task_struct *p, int nice)
- {
- struct sched_attr attr = {
- .sched_policy = SCHED_NORMAL,
- .sched_nice = nice,
- };
- WARN_ON_ONCE(sched_setattr_nocheck(p, &attr) != 0);
- }
- EXPORT_SYMBOL_GPL(sched_set_normal);
- 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;
- /* 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;
- /* ABI compatibility quirk: */
- if (!size)
- size = SCHED_ATTR_SIZE_VER0;
- if (size < SCHED_ATTR_SIZE_VER0 || size > PAGE_SIZE)
- goto err_size;
- ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
- if (ret) {
- if (ret == -E2BIG)
- goto err_size;
- return ret;
- }
- if ((attr->sched_flags & SCHED_FLAG_UTIL_CLAMP) &&
- size < SCHED_ATTR_SIZE_VER1)
- return -EINVAL;
- /*
- * 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;
- }
- static void get_params(struct task_struct *p, struct sched_attr *attr)
- {
- 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);
- }
- /**
- * 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)
- {
- 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;
- if (attr.sched_flags & SCHED_FLAG_KEEP_POLICY)
- attr.sched_policy = SETPARAM_POLICY;
- rcu_read_lock();
- retval = -ESRCH;
- p = find_process_by_pid(pid);
- if (likely(p))
- get_task_struct(p);
- rcu_read_unlock();
- if (likely(p)) {
- if (attr.sched_flags & SCHED_FLAG_KEEP_PARAMS)
- get_params(p, &attr);
- retval = sched_setattr(p, &attr);
- put_task_struct(p);
- }
- 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;
- }
- /*
- * Copy the kernel size attribute structure (which might be larger
- * than what user-space knows about) to user-space.
- *
- * Note that all cases are valid: user-space buffer can be larger or
- * smaller than the kernel-space buffer. The usual case is that both
- * have the same size.
- */
- static int
- sched_attr_copy_to_user(struct sched_attr __user *uattr,
- struct sched_attr *kattr,
- unsigned int usize)
- {
- unsigned int ksize = sizeof(*kattr);
- if (!access_ok(uattr, usize))
- return -EFAULT;
- /*
- * sched_getattr() ABI forwards and backwards compatibility:
- *
- * If usize == ksize then we just copy everything to user-space and all is good.
- *
- * If usize < ksize then we only copy as much as user-space has space for,
- * this keeps ABI compatibility as well. We skip the rest.
- *
- * If usize > ksize then user-space is using a newer version of the ABI,
- * which part the kernel doesn't know about. Just ignore it - tooling can
- * detect the kernel's knowledge of attributes from the attr->size value
- * which is set to ksize in this case.
- */
- kattr->size = min(usize, ksize);
- if (copy_to_user(uattr, kattr, kattr->size))
- 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.
- * @usize: sizeof(attr) for fwd/bwd comp.
- * @flags: for future extension.
- */
- SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
- unsigned int, usize, unsigned int, flags)
- {
- struct sched_attr kattr = { };
- struct task_struct *p;
- int retval;
- if (!uattr || pid < 0 || usize > PAGE_SIZE ||
- usize < 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;
- kattr.sched_policy = p->policy;
- if (p->sched_reset_on_fork)
- kattr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
- get_params(p, &kattr);
- kattr.sched_flags &= SCHED_FLAG_ALL;
- #ifdef CONFIG_UCLAMP_TASK
- /*
- * This could race with another potential updater, but this is fine
- * because it'll correctly read the old or the new value. We don't need
- * to guarantee who wins the race as long as it doesn't return garbage.
- */
- kattr.sched_util_min = p->uclamp_req[UCLAMP_MIN].value;
- kattr.sched_util_max = p->uclamp_req[UCLAMP_MAX].value;
- #endif
- rcu_read_unlock();
- return sched_attr_copy_to_user(uattr, &kattr, usize);
- 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;
- int skip = 0;
- 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();
- }
- trace_android_vh_sched_setaffinity_early(p, in_mask, &skip);
- if (skip)
- goto out_free_new_mask;
- 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, true);
- 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;
- }
- }
- trace_android_rvh_sched_setaffinity(p, in_mask, &retval);
- 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_mask, 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: size of CPU mask copied to user_mask_ptr 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) {
- unsigned int retlen = min(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.
- */
- static void do_sched_yield(void)
- {
- struct rq_flags rf;
- struct rq *rq;
- rq = this_rq_lock_irq(&rf);
- schedstat_inc(rq->yld_count);
- current->sched_class->yield_task(rq);
- trace_android_rvh_do_sched_yield(rq);
- preempt_disable();
- rq_unlock_irq(rq, &rf);
- sched_preempt_enable_no_resched();
- schedule();
- }
- SYSCALL_DEFINE0(sched_yield)
- {
- do_sched_yield();
- return 0;
- }
- #ifndef CONFIG_PREEMPTION
- int __sched _cond_resched(void)
- {
- if (should_resched(0)) {
- preempt_schedule_common();
- return 1;
- }
- rcu_all_qs();
- return 0;
- }
- EXPORT_SYMBOL(_cond_resched);
- #endif
- /*
- * __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_PREEMPTION. 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);
- /**
- * 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);
- do_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);
- 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);
- int io_schedule_prepare(void)
- {
- int old_iowait = current->in_iowait;
- current->in_iowait = 1;
- blk_schedule_flush_plug(current);
- return old_iowait;
- }
- void io_schedule_finish(int token)
- {
- current->in_iowait = token;
- }
- /*
- * 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 token;
- long ret;
- token = io_schedule_prepare();
- ret = schedule_timeout(timeout);
- io_schedule_finish(token);
- return ret;
- }
- EXPORT_SYMBOL(io_schedule_timeout);
- void __sched io_schedule(void)
- {
- int token;
- token = io_schedule_prepare();
- schedule();
- io_schedule_finish(token);
- }
- EXPORT_SYMBOL(io_schedule);
- /**
- * 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;
- }
- static int sched_rr_get_interval(pid_t pid, struct timespec64 *t)
- {
- struct task_struct *p;
- unsigned int time_slice;
- struct rq_flags rf;
- struct rq *rq;
- int retval;
- 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, &rf);
- 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, &rf);
- rcu_read_unlock();
- jiffies_to_timespec64(time_slice, t);
- return 0;
- out_unlock:
- rcu_read_unlock();
- return retval;
- }
- /**
- * 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 __kernel_timespec __user *, interval)
- {
- struct timespec64 t;
- int retval = sched_rr_get_interval(pid, &t);
- if (retval == 0)
- retval = put_timespec64(&t, interval);
- return retval;
- }
- #ifdef CONFIG_COMPAT_32BIT_TIME
- SYSCALL_DEFINE2(sched_rr_get_interval_time32, pid_t, pid,
- struct old_timespec32 __user *, interval)
- {
- struct timespec64 t;
- int retval = sched_rr_get_interval(pid, &t);
- if (retval == 0)
- retval = put_old_timespec32(&t, interval);
- return retval;
- }
- #endif
- void sched_show_task(struct task_struct *p)
- {
- unsigned long free = 0;
- int ppid;
- if (!try_get_task_stack(p))
- return;
- pr_info("task:%-15.15s state:%c", p->comm, task_state_to_char(p));
- if (p->state == TASK_RUNNING)
- pr_cont(" running task ");
- #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();
- pr_cont(" stack:%5lu pid:%5d ppid:%6d flags:0x%08lx\n",
- free, task_pid_nr(p), ppid,
- (unsigned long)task_thread_info(p)->flags);
- print_worker_info(KERN_INFO, p);
- trace_android_vh_sched_show_task(p);
- show_stack(p, NULL, KERN_INFO);
- put_task_stack(p);
- }
- EXPORT_SYMBOL_GPL(sched_show_task);
- static inline bool
- state_filter_match(unsigned long state_filter, struct task_struct *p)
- {
- /* no filter, everything matches */
- if (!state_filter)
- return true;
- /* filter, but doesn't match */
- if (!(p->state & state_filter))
- return false;
- /*
- * When looking for TASK_UNINTERRUPTIBLE skip TASK_IDLE (allows
- * TASK_KILLABLE).
- */
- if (state_filter == TASK_UNINTERRUPTIBLE && p->state == TASK_IDLE)
- return false;
- return true;
- }
- void show_state_filter(unsigned long state_filter)
- {
- struct task_struct *g, *p;
- 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_match(state_filter, p))
- sched_show_task(p);
- }
- #ifdef CONFIG_SCHED_DEBUG
- if (!state_filter)
- sysrq_sched_debug_show();
- #endif
- rcu_read_unlock();
- /*
- * Only show locks if all tasks are dumped:
- */
- if (!state_filter)
- debug_show_all_locks();
- }
- /**
- * 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 init_idle(struct task_struct *idle, int cpu)
- {
- struct rq *rq = cpu_rq(cpu);
- unsigned long flags;
- __sched_fork(0, idle);
- raw_spin_lock_irqsave(&idle->pi_lock, flags);
- raw_spin_lock(&rq->lock);
- idle->state = TASK_RUNNING;
- idle->se.exec_start = sched_clock();
- idle->flags |= PF_IDLE;
- #ifdef CONFIG_SMP
- /*
- * Its possible that init_idle() gets called multiple times on a task,
- * in that case do_set_cpus_allowed() will not do the right thing.
- *
- * And since this is boot we can forgo the serialization.
- */
- set_cpus_allowed_common(idle, cpumask_of(cpu));
- #endif
- /*
- * 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->idle = idle;
- rcu_assign_pointer(rq->curr, idle);
- idle->on_rq = TASK_ON_RQ_QUEUED;
- #ifdef CONFIG_SMP
- idle->on_cpu = 1;
- #endif
- raw_spin_unlock(&rq->lock);
- raw_spin_unlock_irqrestore(&idle->pi_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);
- #ifdef CONFIG_SMP
- sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
- #endif
- }
- #ifdef CONFIG_SMP
- int cpuset_cpumask_can_shrink(const struct cpumask *cur,
- const struct cpumask *trial)
- {
- int ret = 1;
- if (!cpumask_weight(cur))
- return ret;
- ret = dl_cpuset_cpumask_can_shrink(cur, trial);
- 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_mask may be changed.
- */
- if (p->flags & PF_NO_SETAFFINITY) {
- ret = -EINVAL;
- goto out;
- }
- if (dl_task(p) && !cpumask_intersects(task_rq(p)->rd->span,
- cs_cpus_allowed))
- ret = dl_task_can_attach(p, cs_cpus_allowed);
- out:
- return ret;
- }
- bool sched_smp_initialized __read_mostly;
- #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, p->cpus_ptr))
- 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)
- {
- bool queued, running;
- struct rq_flags rf;
- struct rq *rq;
- rq = task_rq_lock(p, &rf);
- queued = task_on_rq_queued(p);
- running = task_current(rq, p);
- if (queued)
- dequeue_task(rq, p, DEQUEUE_SAVE);
- if (running)
- put_prev_task(rq, p);
- p->numa_preferred_nid = nid;
- if (queued)
- enqueue_task(rq, p, ENQUEUE_RESTORE | ENQUEUE_NOCLOCK);
- if (running)
- set_next_task(rq, p);
- task_rq_unlock(rq, p, &rf);
- }
- #endif /* CONFIG_NUMA_BALANCING */
- #ifdef CONFIG_HOTPLUG_CPU
- /*
- * Ensure 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()));
- BUG_ON(current != this_rq()->idle);
- if (mm != &init_mm) {
- switch_mm(mm, &init_mm, current);
- finish_arch_post_lock_switch();
- }
- /* finish_cpu(), as ran on the BP, will clean up the active_mm state */
- }
- /*
- * 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. We need to take the teardown thread which
- * is calling this into account, so we hand in adjust = 1 to the load
- * calculation.
- *
- * Also see the comment "Global load-average calculations".
- */
- static void calc_load_migrate(struct rq *rq)
- {
- long delta = calc_load_fold_active(rq, 1);
- if (delta)
- atomic_long_add(delta, &calc_load_tasks);
- }
- static struct task_struct *__pick_migrate_task(struct rq *rq)
- {
- const struct sched_class *class;
- struct task_struct *next;
- for_each_class(class) {
- next = class->pick_next_task(rq);
- if (next) {
- next->sched_class->put_prev_task(rq, next);
- return next;
- }
- }
- /* The idle class should always have a runnable task */
- BUG();
- }
- /*
- * 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.
- *
- * force: if false, the function will skip CPU pinned kthreads.
- */
- static void migrate_tasks(struct rq *dead_rq, struct rq_flags *rf, bool force)
- {
- struct rq *rq = dead_rq;
- struct task_struct *next, *tmp, *stop = rq->stop;
- LIST_HEAD(percpu_kthreads);
- struct rq_flags orf = *rf;
- 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);
- #ifdef CONFIG_SCHED_DEBUG
- /* note the clock update in orf */
- orf.clock_update_flags |= RQCF_UPDATED;
- #endif
- for (;;) {
- /*
- * There's this thread running, bail when that's the only
- * remaining thread:
- */
- if (rq->nr_running == 1)
- break;
- next = __pick_migrate_task(rq);
- /*
- * Argh ... no iterator for tasks, we need to remove the
- * kthread from the run-queue to continue.
- */
- if (!force && is_per_cpu_kthread(next)) {
- INIT_LIST_HEAD(&next->percpu_kthread_node);
- list_add(&next->percpu_kthread_node, &percpu_kthreads);
- /* DEQUEUE_SAVE not used due to move_entity in rt */
- deactivate_task(rq, next,
- DEQUEUE_NOCLOCK);
- continue;
- }
- /*
- * Rules for changing task_struct::cpus_mask are holding
- * both pi_lock and rq->lock, such that holding either
- * stabilizes the mask.
- *
- * Drop rq->lock is not quite as disastrous as it usually is
- * because !cpu_active at this point, which means load-balance
- * will not interfere. Also, stop-machine.
- */
- rq_unlock(rq, rf);
- raw_spin_lock(&next->pi_lock);
- rq_relock(rq, rf);
- /*
- * Since we're inside stop-machine, _nothing_ should have
- * changed the task, WARN if weird stuff happened, because in
- * that case the above rq->lock drop is a fail too.
- */
- if (task_rq(next) != rq || !task_on_rq_queued(next)) {
- /*
- * In the !force case, there is a hole between
- * rq_unlock() and rq_relock(), where another CPU might
- * not observe an up to date cpu_active_mask and try to
- * move tasks around.
- */
- WARN_ON(force);
- raw_spin_unlock(&next->pi_lock);
- continue;
- }
- /* Find suitable destination for @next, with force if needed. */
- dest_cpu = select_fallback_rq(dead_rq->cpu, next);
- rq = __migrate_task(rq, rf, next, dest_cpu);
- if (rq != dead_rq) {
- rq_unlock(rq, rf);
- rq = dead_rq;
- *rf = orf;
- rq_relock(rq, rf);
- }
- raw_spin_unlock(&next->pi_lock);
- }
- list_for_each_entry_safe(next, tmp, &percpu_kthreads,
- percpu_kthread_node) {
- /* ENQUEUE_RESTORE not used due to move_entity in rt */
- activate_task(rq, next, ENQUEUE_NOCLOCK);
- list_del(&next->percpu_kthread_node);
- }
- rq->stop = stop;
- }
- static int drain_rq_cpu_stop(void *data)
- {
- struct rq *rq = this_rq();
- struct rq_flags rf;
- rq_lock_irqsave(rq, &rf);
- migrate_tasks(rq, &rf, false);
- rq_unlock_irqrestore(rq, &rf);
- return 0;
- }
- int sched_cpu_drain_rq(unsigned int cpu)
- {
- struct cpu_stop_work *rq_drain = &(cpu_rq(cpu)->drain);
- struct cpu_stop_done *rq_drain_done = &(cpu_rq(cpu)->drain_done);
- if (idle_cpu(cpu)) {
- rq_drain->done = NULL;
- return 0;
- }
- return stop_one_cpu_async(cpu, drain_rq_cpu_stop, NULL, rq_drain,
- rq_drain_done);
- }
- void sched_cpu_drain_rq_wait(unsigned int cpu)
- {
- struct cpu_stop_work *rq_drain = &(cpu_rq(cpu)->drain);
- if (rq_drain->done)
- cpu_stop_work_wait(rq_drain);
- }
- #endif /* CONFIG_HOTPLUG_CPU */
- 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);
- }
- }
- }
- 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;
- }
- }
- /*
- * used to mark begin/end of suspend/resume:
- */
- static int num_cpus_frozen;
- /*
- * 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 void cpuset_cpu_active(void)
- {
- if (cpuhp_tasks_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)
- return;
- /*
- * This is the last CPU online operation. So fall through and
- * restore the original sched domains by considering the
- * cpuset configurations.
- */
- cpuset_force_rebuild();
- }
- cpuset_update_active_cpus();
- }
- static int cpuset_cpu_inactive(unsigned int cpu)
- {
- if (!cpuhp_tasks_frozen) {
- if (dl_cpu_busy(cpu))
- return -EBUSY;
- cpuset_update_active_cpus();
- } else {
- num_cpus_frozen++;
- partition_sched_domains(1, NULL, NULL);
- }
- return 0;
- }
- int sched_cpu_activate(unsigned int cpu)
- {
- struct rq *rq = cpu_rq(cpu);
- struct rq_flags rf;
- #ifdef CONFIG_SCHED_SMT
- /*
- * When going up, increment the number of cores with SMT present.
- */
- if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
- static_branch_inc_cpuslocked(&sched_smt_present);
- #endif
- set_cpu_active(cpu, true);
- if (sched_smp_initialized) {
- sched_domains_numa_masks_set(cpu);
- cpuset_cpu_active();
- }
- /*
- * Put the rq online, if not already. This happens:
- *
- * 1) In the early boot process, because we build the real domains
- * after all CPUs have been brought up.
- *
- * 2) At runtime, if cpuset_cpu_active() fails to rebuild the
- * domains.
- */
- rq_lock_irqsave(rq, &rf);
- if (rq->rd) {
- BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
- set_rq_online(rq);
- }
- rq_unlock_irqrestore(rq, &rf);
- update_max_interval();
- return 0;
- }
- int sched_cpus_activate(struct cpumask *cpus)
- {
- unsigned int cpu;
- for_each_cpu(cpu, cpus) {
- if (sched_cpu_activate(cpu)) {
- for_each_cpu_and(cpu, cpus, cpu_active_mask)
- sched_cpu_deactivate(cpu);
- return -EBUSY;
- }
- }
- return 0;
- }
- int _sched_cpu_deactivate(unsigned int cpu)
- {
- int ret;
- set_cpu_active(cpu, false);
- #ifdef CONFIG_SCHED_SMT
- /*
- * When going down, decrement the number of cores with SMT present.
- */
- if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
- static_branch_dec_cpuslocked(&sched_smt_present);
- #endif
- if (!sched_smp_initialized)
- return 0;
- ret = cpuset_cpu_inactive(cpu);
- if (ret) {
- set_cpu_active(cpu, true);
- return ret;
- }
- sched_domains_numa_masks_clear(cpu);
- update_max_interval();
- return 0;
- }
- int sched_cpu_deactivate(unsigned int cpu)
- {
- int ret = _sched_cpu_deactivate(cpu);
- if (ret)
- return ret;
- /*
- * We've cleared cpu_active_mask, wait for all preempt-disabled and RCU
- * users of this state to go away such that all new such users will
- * observe it.
- *
- * Do sync before park smpboot threads to take care the rcu boost case.
- */
- synchronize_rcu();
- return 0;
- }
- int sched_cpus_deactivate_nosync(struct cpumask *cpus)
- {
- unsigned int cpu;
- for_each_cpu(cpu, cpus) {
- if (_sched_cpu_deactivate(cpu)) {
- for_each_cpu(cpu, cpus) {
- if (!cpu_active(cpu))
- sched_cpu_activate(cpu);
- }
- return -EBUSY;
- }
- }
- return 0;
- }
- static void sched_rq_cpu_starting(unsigned int cpu)
- {
- struct rq *rq = cpu_rq(cpu);
- rq->calc_load_update = calc_load_update;
- }
- int sched_cpu_starting(unsigned int cpu)
- {
- sched_rq_cpu_starting(cpu);
- sched_tick_start(cpu);
- trace_android_rvh_sched_cpu_starting(cpu);
- return 0;
- }
- #ifdef CONFIG_HOTPLUG_CPU
- int sched_cpu_dying(unsigned int cpu)
- {
- struct rq *rq = cpu_rq(cpu);
- struct rq_flags rf;
- /* Handle pending wakeups and then migrate everything off */
- sched_tick_stop(cpu);
- rq_lock_irqsave(rq, &rf);
- if (rq->rd) {
- BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
- set_rq_offline(rq);
- }
- migrate_tasks(rq, &rf, true);
- BUG_ON(rq->nr_running != 1);
- rq_unlock_irqrestore(rq, &rf);
- trace_android_rvh_sched_cpu_dying(cpu);
- calc_load_migrate(rq);
- nohz_balance_exit_idle(rq);
- hrtick_clear(rq);
- return 0;
- }
- #endif
- void __init sched_init_smp(void)
- {
- 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);
- sched_init_domains(cpu_active_mask);
- mutex_unlock(&sched_domains_mutex);
- /* Move init over to a non-isolated CPU */
- if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_DOMAIN)) < 0)
- BUG();
- sched_init_granularity();
- init_sched_rt_class();
- init_sched_dl_class();
- sched_smp_initialized = true;
- }
- static int __init migration_init(void)
- {
- sched_cpu_starting(smp_processor_id());
- return 0;
- }
- early_initcall(migration_init);
- #else
- void __init sched_init_smp(void)
- {
- sched_init_granularity();
- }
- #endif /* CONFIG_SMP */
- 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;
- EXPORT_SYMBOL_GPL(root_task_group);
- LIST_HEAD(task_groups);
- EXPORT_SYMBOL_GPL(task_groups);
- /* Cacheline aligned slab cache for task_group */
- static struct kmem_cache *task_group_cache __read_mostly;
- #endif
- DECLARE_PER_CPU(cpumask_var_t, load_balance_mask);
- DECLARE_PER_CPU(cpumask_var_t, select_idle_mask);
- void __init sched_init(void)
- {
- unsigned long ptr = 0;
- int i;
- /* Make sure the linker didn't screw up */
- BUG_ON(&idle_sched_class + 1 != &fair_sched_class ||
- &fair_sched_class + 1 != &rt_sched_class ||
- &rt_sched_class + 1 != &dl_sched_class);
- #ifdef CONFIG_SMP
- BUG_ON(&dl_sched_class + 1 != &stop_sched_class);
- #endif
- wait_bit_init();
- #ifdef CONFIG_FAIR_GROUP_SCHED
- ptr += 2 * nr_cpu_ids * sizeof(void **);
- #endif
- #ifdef CONFIG_RT_GROUP_SCHED
- ptr += 2 * nr_cpu_ids * sizeof(void **);
- #endif
- if (ptr) {
- ptr = (unsigned long)kzalloc(ptr, 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 **);
- root_task_group.shares = ROOT_TASK_GROUP_LOAD;
- init_cfs_bandwidth(&root_task_group.cfs_bandwidth);
- #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));
- per_cpu(select_idle_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
- task_group_cache = KMEM_CACHE(task_group, 0);
- 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
- INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
- rq->tmp_alone_branch = &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_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
- #ifdef CONFIG_SMP
- rq->sd = NULL;
- rq->rd = NULL;
- rq->cpu_capacity = rq->cpu_capacity_orig = SCHED_CAPACITY_SCALE;
- rq->balance_callback = NULL;
- 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->last_blocked_load_update_tick = jiffies;
- atomic_set(&rq->nohz_flags, 0);
- rq_csd_init(rq, &rq->nohz_csd, nohz_csd_func);
- #endif
- #endif /* CONFIG_SMP */
- hrtick_rq_init(rq);
- atomic_set(&rq->nr_iowait, 0);
- }
- set_load_weight(&init_task, false);
- /*
- * The boot idle thread does lazy MMU switching as well:
- */
- mmgrab(&init_mm);
- enter_lazy_tlb(&init_mm, current);
- /*
- * 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
- idle_thread_set_boot_cpu();
- #endif
- init_sched_fair_class();
- init_schedstats();
- psi_init();
- init_uclamp();
- scheduler_running = 1;
- }
- #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
- static inline int preempt_count_equals(int preempt_offset)
- {
- int nested = preempt_count() + 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)
- {
- /* Ratelimiting timestamp: */
- static unsigned long prev_jiffy;
- unsigned long preempt_disable_ip;
- /* WARN_ON_ONCE() by default, no rate limit required: */
- rcu_sleep_check();
- if ((preempt_count_equals(preempt_offset) && !irqs_disabled() &&
- !is_idle_task(current) && !current->non_block_count) ||
- system_state == SYSTEM_BOOTING || system_state > SYSTEM_RUNNING ||
- oops_in_progress)
- return;
- if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
- return;
- prev_jiffy = jiffies;
- /* Save this before calling printk(), since that will clobber it: */
- preempt_disable_ip = get_preempt_disable_ip(current);
- 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, non_block: %d, pid: %d, name: %s\n",
- in_atomic(), irqs_disabled(), current->non_block_count,
- 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);
- if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
- && !preempt_count_equals(preempt_offset)) {
- pr_err("Preemption disabled at:");
- print_ip_sym(KERN_ERR, preempt_disable_ip);
- }
- trace_android_rvh_schedule_bug(NULL);
- dump_stack();
- add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
- }
- EXPORT_SYMBOL(___might_sleep);
- void __cant_sleep(const char *file, int line, int preempt_offset)
- {
- static unsigned long prev_jiffy;
- if (irqs_disabled())
- return;
- if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
- return;
- if (preempt_count() > preempt_offset)
- return;
- if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
- return;
- prev_jiffy = jiffies;
- printk(KERN_ERR "BUG: assuming atomic 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);
- debug_show_held_locks(current);
- dump_stack();
- add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
- }
- EXPORT_SYMBOL_GPL(__cant_sleep);
- #endif
- #ifdef CONFIG_MAGIC_SYSRQ
- void normalize_rt_tasks(void)
- {
- struct task_struct *g, *p;
- struct sched_attr attr = {
- .sched_policy = SCHED_NORMAL,
- };
- 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;
- schedstat_set(p->se.statistics.wait_start, 0);
- schedstat_set(p->se.statistics.sleep_start, 0);
- schedstat_set(p->se.statistics.block_start, 0);
- 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;
- }
- __sched_setscheduler(p, &attr, false, false);
- }
- 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
- /**
- * 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 ia64_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 inline void alloc_uclamp_sched_group(struct task_group *tg,
- struct task_group *parent)
- {
- #ifdef CONFIG_UCLAMP_TASK_GROUP
- enum uclamp_id clamp_id;
- for_each_clamp_id(clamp_id) {
- uclamp_se_set(&tg->uclamp_req[clamp_id],
- uclamp_none(clamp_id), false);
- tg->uclamp[clamp_id] = parent->uclamp[clamp_id];
- }
- #endif
- }
- static void sched_free_group(struct task_group *tg)
- {
- free_fair_sched_group(tg);
- free_rt_sched_group(tg);
- autogroup_free(tg);
- kmem_cache_free(task_group_cache, tg);
- }
- /* allocate runqueue etc for a new task group */
- struct task_group *sched_create_group(struct task_group *parent)
- {
- struct task_group *tg;
- tg = kmem_cache_alloc(task_group_cache, GFP_KERNEL | __GFP_ZERO);
- if (!tg)
- return ERR_PTR(-ENOMEM);
- if (!alloc_fair_sched_group(tg, parent))
- goto err;
- if (!alloc_rt_sched_group(tg, parent))
- goto err;
- alloc_uclamp_sched_group(tg, parent);
- return tg;
- err:
- sched_free_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);
- /* Root should already exist: */
- WARN_ON(!parent);
- tg->parent = parent;
- INIT_LIST_HEAD(&tg->children);
- list_add_rcu(&tg->siblings, &parent->children);
- spin_unlock_irqrestore(&task_group_lock, flags);
- online_fair_sched_group(tg);
- }
- /* rcu callback to free various structures associated with a task group */
- static void sched_free_group_rcu(struct rcu_head *rhp)
- {
- /* Now it should be safe to free those cfs_rqs: */
- sched_free_group(container_of(rhp, struct task_group, rcu));
- }
- void sched_destroy_group(struct task_group *tg)
- {
- /* Wait for possible concurrent references to cfs_rqs complete: */
- call_rcu(&tg->rcu, sched_free_group_rcu);
- }
- void sched_offline_group(struct task_group *tg)
- {
- unsigned long flags;
- /* End participation in shares distribution: */
- unregister_fair_sched_group(tg);
- spin_lock_irqsave(&task_group_lock, flags);
- list_del_rcu(&tg->list);
- list_del_rcu(&tg->siblings);
- spin_unlock_irqrestore(&task_group_lock, flags);
- }
- static void sched_change_group(struct task_struct *tsk, int type)
- {
- struct task_group *tg;
- /*
- * 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_change_group)
- tsk->sched_class->task_change_group(tsk, type);
- else
- #endif
- set_task_rq(tsk, task_cpu(tsk));
- }
- /*
- * 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)
- {
- int queued, running, queue_flags =
- DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK;
- struct rq_flags rf;
- struct rq *rq;
- rq = task_rq_lock(tsk, &rf);
- update_rq_clock(rq);
- running = task_current(rq, tsk);
- queued = task_on_rq_queued(tsk);
- if (queued)
- dequeue_task(rq, tsk, queue_flags);
- if (running)
- put_prev_task(rq, tsk);
- sched_change_group(tsk, TASK_MOVE_GROUP);
- if (queued)
- enqueue_task(rq, tsk, queue_flags);
- if (running) {
- set_next_task(rq, tsk);
- /*
- * After changing group, the running task may have joined a
- * throttled one but it's still the running task. Trigger a
- * resched to make sure that task can still run.
- */
- resched_curr(rq);
- }
- task_rq_unlock(rq, tsk, &rf);
- }
- 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;
- }
- /* Expose task group only after completing cgroup initialization */
- 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);
- #ifdef CONFIG_UCLAMP_TASK_GROUP
- /* Propagate the effective uclamp value for the new group */
- mutex_lock(&uclamp_mutex);
- rcu_read_lock();
- cpu_util_update_eff(css);
- rcu_read_unlock();
- mutex_unlock(&uclamp_mutex);
- #endif
- trace_android_rvh_cpu_cgroup_online(css);
- return 0;
- }
- static void cpu_cgroup_css_released(struct cgroup_subsys_state *css)
- {
- struct task_group *tg = css_tg(css);
- sched_offline_group(tg);
- }
- static void cpu_cgroup_css_free(struct cgroup_subsys_state *css)
- {
- struct task_group *tg = css_tg(css);
- /*
- * Relies on the RCU grace period between css_released() and this.
- */
- sched_free_group(tg);
- }
- /*
- * This is called before wake_up_new_task(), therefore we really only
- * have to set its group bits, all the other stuff does not apply.
- */
- static void cpu_cgroup_fork(struct task_struct *task)
- {
- struct rq_flags rf;
- struct rq *rq;
- rq = task_rq_lock(task, &rf);
- update_rq_clock(rq);
- sched_change_group(task, TASK_SET_GROUP);
- task_rq_unlock(rq, task, &rf);
- }
- static int cpu_cgroup_can_attach(struct cgroup_taskset *tset)
- {
- struct task_struct *task;
- struct cgroup_subsys_state *css;
- int ret = 0;
- cgroup_taskset_for_each(task, css, tset) {
- #ifdef CONFIG_RT_GROUP_SCHED
- if (!sched_rt_can_attach(css_tg(css), task))
- return -EINVAL;
- #endif
- /*
- * Serialize against wake_up_new_task() such that if its
- * running, we're sure to observe its full state.
- */
- raw_spin_lock_irq(&task->pi_lock);
- /*
- * Avoid calling sched_move_task() before wake_up_new_task()
- * has happened. This would lead to problems with PELT, due to
- * move wanting to detach+attach while we're not attached yet.
- */
- if (task->state == TASK_NEW)
- ret = -EINVAL;
- raw_spin_unlock_irq(&task->pi_lock);
- if (ret)
- break;
- }
- trace_android_rvh_cpu_cgroup_can_attach(tset, &ret);
- return ret;
- }
- static void cpu_cgroup_attach(struct cgroup_taskset *tset)
- {
- struct task_struct *task;
- struct cgroup_subsys_state *css;
- cgroup_taskset_for_each(task, css, tset)
- sched_move_task(task);
- trace_android_rvh_cpu_cgroup_attach(tset);
- }
- #ifdef CONFIG_UCLAMP_TASK_GROUP
- static void cpu_util_update_eff(struct cgroup_subsys_state *css)
- {
- struct cgroup_subsys_state *top_css = css;
- struct uclamp_se *uc_parent = NULL;
- struct uclamp_se *uc_se = NULL;
- unsigned int eff[UCLAMP_CNT];
- enum uclamp_id clamp_id;
- unsigned int clamps;
- lockdep_assert_held(&uclamp_mutex);
- SCHED_WARN_ON(!rcu_read_lock_held());
- css_for_each_descendant_pre(css, top_css) {
- uc_parent = css_tg(css)->parent
- ? css_tg(css)->parent->uclamp : NULL;
- for_each_clamp_id(clamp_id) {
- /* Assume effective clamps matches requested clamps */
- eff[clamp_id] = css_tg(css)->uclamp_req[clamp_id].value;
- /* Cap effective clamps with parent's effective clamps */
- if (uc_parent &&
- eff[clamp_id] > uc_parent[clamp_id].value) {
- eff[clamp_id] = uc_parent[clamp_id].value;
- }
- }
- /* Ensure protection is always capped by limit */
- eff[UCLAMP_MIN] = min(eff[UCLAMP_MIN], eff[UCLAMP_MAX]);
- /* Propagate most restrictive effective clamps */
- clamps = 0x0;
- uc_se = css_tg(css)->uclamp;
- for_each_clamp_id(clamp_id) {
- if (eff[clamp_id] == uc_se[clamp_id].value)
- continue;
- uc_se[clamp_id].value = eff[clamp_id];
- uc_se[clamp_id].bucket_id = uclamp_bucket_id(eff[clamp_id]);
- clamps |= (0x1 << clamp_id);
- }
- if (!clamps) {
- css = css_rightmost_descendant(css);
- continue;
- }
- /* Immediately update descendants RUNNABLE tasks */
- uclamp_update_active_tasks(css);
- }
- }
- /*
- * Integer 10^N with a given N exponent by casting to integer the literal "1eN"
- * C expression. Since there is no way to convert a macro argument (N) into a
- * character constant, use two levels of macros.
- */
- #define _POW10(exp) ((unsigned int)1e##exp)
- #define POW10(exp) _POW10(exp)
- struct uclamp_request {
- #define UCLAMP_PERCENT_SHIFT 2
- #define UCLAMP_PERCENT_SCALE (100 * POW10(UCLAMP_PERCENT_SHIFT))
- s64 percent;
- u64 util;
- int ret;
- };
- static inline struct uclamp_request
- capacity_from_percent(char *buf)
- {
- struct uclamp_request req = {
- .percent = UCLAMP_PERCENT_SCALE,
- .util = SCHED_CAPACITY_SCALE,
- .ret = 0,
- };
- buf = strim(buf);
- if (strcmp(buf, "max")) {
- req.ret = cgroup_parse_float(buf, UCLAMP_PERCENT_SHIFT,
- &req.percent);
- if (req.ret)
- return req;
- if ((u64)req.percent > UCLAMP_PERCENT_SCALE) {
- req.ret = -ERANGE;
- return req;
- }
- req.util = req.percent << SCHED_CAPACITY_SHIFT;
- req.util = DIV_ROUND_CLOSEST_ULL(req.util, UCLAMP_PERCENT_SCALE);
- }
- return req;
- }
- static ssize_t cpu_uclamp_write(struct kernfs_open_file *of, char *buf,
- size_t nbytes, loff_t off,
- enum uclamp_id clamp_id)
- {
- struct uclamp_request req;
- struct task_group *tg;
- req = capacity_from_percent(buf);
- if (req.ret)
- return req.ret;
- static_branch_enable(&sched_uclamp_used);
- mutex_lock(&uclamp_mutex);
- rcu_read_lock();
- tg = css_tg(of_css(of));
- if (tg->uclamp_req[clamp_id].value != req.util)
- uclamp_se_set(&tg->uclamp_req[clamp_id], req.util, false);
- /*
- * Because of not recoverable conversion rounding we keep track of the
- * exact requested value
- */
- tg->uclamp_pct[clamp_id] = req.percent;
- /* Update effective clamps to track the most restrictive value */
- cpu_util_update_eff(of_css(of));
- rcu_read_unlock();
- mutex_unlock(&uclamp_mutex);
- return nbytes;
- }
- static ssize_t cpu_uclamp_min_write(struct kernfs_open_file *of,
- char *buf, size_t nbytes,
- loff_t off)
- {
- return cpu_uclamp_write(of, buf, nbytes, off, UCLAMP_MIN);
- }
- static ssize_t cpu_uclamp_max_write(struct kernfs_open_file *of,
- char *buf, size_t nbytes,
- loff_t off)
- {
- return cpu_uclamp_write(of, buf, nbytes, off, UCLAMP_MAX);
- }
- static inline void cpu_uclamp_print(struct seq_file *sf,
- enum uclamp_id clamp_id)
- {
- struct task_group *tg;
- u64 util_clamp;
- u64 percent;
- u32 rem;
- rcu_read_lock();
- tg = css_tg(seq_css(sf));
- util_clamp = tg->uclamp_req[clamp_id].value;
- rcu_read_unlock();
- if (util_clamp == SCHED_CAPACITY_SCALE) {
- seq_puts(sf, "max\n");
- return;
- }
- percent = tg->uclamp_pct[clamp_id];
- percent = div_u64_rem(percent, POW10(UCLAMP_PERCENT_SHIFT), &rem);
- seq_printf(sf, "%llu.%0*u\n", percent, UCLAMP_PERCENT_SHIFT, rem);
- }
- static int cpu_uclamp_min_show(struct seq_file *sf, void *v)
- {
- cpu_uclamp_print(sf, UCLAMP_MIN);
- return 0;
- }
- static int cpu_uclamp_max_show(struct seq_file *sf, void *v)
- {
- cpu_uclamp_print(sf, UCLAMP_MAX);
- return 0;
- }
- static int cpu_uclamp_ls_write_u64(struct cgroup_subsys_state *css,
- struct cftype *cftype, u64 ls)
- {
- struct task_group *tg;
- if (ls > 1)
- return -EINVAL;
- tg = css_tg(css);
- tg->latency_sensitive = (unsigned int) ls;
- return 0;
- }
- static u64 cpu_uclamp_ls_read_u64(struct cgroup_subsys_state *css,
- struct cftype *cft)
- {
- struct task_group *tg = css_tg(css);
- return (u64) tg->latency_sensitive;
- }
- #endif /* CONFIG_UCLAMP_TASK_GROUP */
- #ifdef CONFIG_FAIR_GROUP_SCHED
- static int cpu_shares_write_u64(struct cgroup_subsys_state *css,
- struct cftype *cftype, u64 shareval)
- {
- if (shareval > scale_load_down(ULONG_MAX))
- shareval = MAX_SHARES;
- 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 */
- static const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */
- /* More than 203 days if BW_SHIFT equals 20. */
- static const u64 max_cfs_runtime = MAX_BW * NSEC_PER_USEC;
- 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;
- /*
- * Bound quota to defend quota against overflow during bandwidth shift.
- */
- if (quota != RUNTIME_INF && quota > max_cfs_runtime)
- 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)
- start_cfs_bandwidth(cfs_b);
- 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;
- struct rq_flags rf;
- rq_lock_irq(rq, &rf);
- cfs_rq->runtime_enabled = runtime_enabled;
- cfs_rq->runtime_remaining = 0;
- if (cfs_rq->throttled)
- unthrottle_cfs_rq(cfs_rq);
- rq_unlock_irq(rq, &rf);
- }
- if (runtime_was_enabled && !runtime_enabled)
- cfs_bandwidth_usage_dec();
- out_unlock:
- mutex_unlock(&cfs_constraints_mutex);
- put_online_cpus();
- return ret;
- }
- static 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 if ((u64)cfs_quota_us <= U64_MAX / NSEC_PER_USEC)
- quota = (u64)cfs_quota_us * NSEC_PER_USEC;
- else
- return -EINVAL;
- return tg_set_cfs_bandwidth(tg, period, quota);
- }
- static 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;
- }
- static int tg_set_cfs_period(struct task_group *tg, long cfs_period_us)
- {
- u64 quota, period;
- if ((u64)cfs_period_us > U64_MAX / NSEC_PER_USEC)
- return -EINVAL;
- period = (u64)cfs_period_us * NSEC_PER_USEC;
- quota = tg->cfs_bandwidth.quota;
- return tg_set_cfs_bandwidth(tg, period, quota);
- }
- static 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. On cgroup2,
- * always take the min. On cgroup1, only inherit when no
- * limit is set:
- */
- if (cgroup_subsys_on_dfl(cpu_cgrp_subsys)) {
- quota = min(quota, parent_quota);
- } else {
- 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_cfs_stat_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);
- if (schedstat_enabled() && tg != &root_task_group) {
- u64 ws = 0;
- int i;
- for_each_possible_cpu(i)
- ws += schedstat_val(tg->se[i]->statistics.wait_sum);
- seq_printf(sf, "wait_sum %llu\n", ws);
- }
- 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_legacy_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_cfs_stat_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
- #ifdef CONFIG_UCLAMP_TASK_GROUP
- {
- .name = "uclamp.min",
- .flags = CFTYPE_NOT_ON_ROOT,
- .seq_show = cpu_uclamp_min_show,
- .write = cpu_uclamp_min_write,
- },
- {
- .name = "uclamp.max",
- .flags = CFTYPE_NOT_ON_ROOT,
- .seq_show = cpu_uclamp_max_show,
- .write = cpu_uclamp_max_write,
- },
- {
- .name = "uclamp.latency_sensitive",
- .flags = CFTYPE_NOT_ON_ROOT,
- .read_u64 = cpu_uclamp_ls_read_u64,
- .write_u64 = cpu_uclamp_ls_write_u64,
- },
- #endif
- { } /* Terminate */
- };
- static int cpu_extra_stat_show(struct seq_file *sf,
- struct cgroup_subsys_state *css)
- {
- #ifdef CONFIG_CFS_BANDWIDTH
- {
- struct task_group *tg = css_tg(css);
- struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
- u64 throttled_usec;
- throttled_usec = cfs_b->throttled_time;
- do_div(throttled_usec, NSEC_PER_USEC);
- seq_printf(sf, "nr_periods %d\n"
- "nr_throttled %d\n"
- "throttled_usec %llu\n",
- cfs_b->nr_periods, cfs_b->nr_throttled,
- throttled_usec);
- }
- #endif
- return 0;
- }
- #ifdef CONFIG_FAIR_GROUP_SCHED
- static u64 cpu_weight_read_u64(struct cgroup_subsys_state *css,
- struct cftype *cft)
- {
- struct task_group *tg = css_tg(css);
- u64 weight = scale_load_down(tg->shares);
- return DIV_ROUND_CLOSEST_ULL(weight * CGROUP_WEIGHT_DFL, 1024);
- }
- static int cpu_weight_write_u64(struct cgroup_subsys_state *css,
- struct cftype *cft, u64 weight)
- {
- /*
- * cgroup weight knobs should use the common MIN, DFL and MAX
- * values which are 1, 100 and 10000 respectively. While it loses
- * a bit of range on both ends, it maps pretty well onto the shares
- * value used by scheduler and the round-trip conversions preserve
- * the original value over the entire range.
- */
- if (weight < CGROUP_WEIGHT_MIN || weight > CGROUP_WEIGHT_MAX)
- return -ERANGE;
- weight = DIV_ROUND_CLOSEST_ULL(weight * 1024, CGROUP_WEIGHT_DFL);
- return sched_group_set_shares(css_tg(css), scale_load(weight));
- }
- static s64 cpu_weight_nice_read_s64(struct cgroup_subsys_state *css,
- struct cftype *cft)
- {
- unsigned long weight = scale_load_down(css_tg(css)->shares);
- int last_delta = INT_MAX;
- int prio, delta;
- /* find the closest nice value to the current weight */
- for (prio = 0; prio < ARRAY_SIZE(sched_prio_to_weight); prio++) {
- delta = abs(sched_prio_to_weight[prio] - weight);
- if (delta >= last_delta)
- break;
- last_delta = delta;
- }
- return PRIO_TO_NICE(prio - 1 + MAX_RT_PRIO);
- }
- static int cpu_weight_nice_write_s64(struct cgroup_subsys_state *css,
- struct cftype *cft, s64 nice)
- {
- unsigned long weight;
- int idx;
- if (nice < MIN_NICE || nice > MAX_NICE)
- return -ERANGE;
- idx = NICE_TO_PRIO(nice) - MAX_RT_PRIO;
- idx = array_index_nospec(idx, 40);
- weight = sched_prio_to_weight[idx];
- return sched_group_set_shares(css_tg(css), scale_load(weight));
- }
- #endif
- static void __maybe_unused cpu_period_quota_print(struct seq_file *sf,
- long period, long quota)
- {
- if (quota < 0)
- seq_puts(sf, "max");
- else
- seq_printf(sf, "%ld", quota);
- seq_printf(sf, " %ld\n", period);
- }
- /* caller should put the current value in *@periodp before calling */
- static int __maybe_unused cpu_period_quota_parse(char *buf,
- u64 *periodp, u64 *quotap)
- {
- char tok[21]; /* U64_MAX */
- if (sscanf(buf, "%20s %llu", tok, periodp) < 1)
- return -EINVAL;
- *periodp *= NSEC_PER_USEC;
- if (sscanf(tok, "%llu", quotap))
- *quotap *= NSEC_PER_USEC;
- else if (!strcmp(tok, "max"))
- *quotap = RUNTIME_INF;
- else
- return -EINVAL;
- return 0;
- }
- #ifdef CONFIG_CFS_BANDWIDTH
- static int cpu_max_show(struct seq_file *sf, void *v)
- {
- struct task_group *tg = css_tg(seq_css(sf));
- cpu_period_quota_print(sf, tg_get_cfs_period(tg), tg_get_cfs_quota(tg));
- return 0;
- }
- static ssize_t cpu_max_write(struct kernfs_open_file *of,
- char *buf, size_t nbytes, loff_t off)
- {
- struct task_group *tg = css_tg(of_css(of));
- u64 period = tg_get_cfs_period(tg);
- u64 quota;
- int ret;
- ret = cpu_period_quota_parse(buf, &period, "a);
- if (!ret)
- ret = tg_set_cfs_bandwidth(tg, period, quota);
- return ret ?: nbytes;
- }
- #endif
- static struct cftype cpu_files[] = {
- #ifdef CONFIG_FAIR_GROUP_SCHED
- {
- .name = "weight",
- .flags = CFTYPE_NOT_ON_ROOT,
- .read_u64 = cpu_weight_read_u64,
- .write_u64 = cpu_weight_write_u64,
- },
- {
- .name = "weight.nice",
- .flags = CFTYPE_NOT_ON_ROOT,
- .read_s64 = cpu_weight_nice_read_s64,
- .write_s64 = cpu_weight_nice_write_s64,
- },
- #endif
- #ifdef CONFIG_CFS_BANDWIDTH
- {
- .name = "max",
- .flags = CFTYPE_NOT_ON_ROOT,
- .seq_show = cpu_max_show,
- .write = cpu_max_write,
- },
- #endif
- #ifdef CONFIG_UCLAMP_TASK_GROUP
- {
- .name = "uclamp.min",
- .flags = CFTYPE_NOT_ON_ROOT,
- .seq_show = cpu_uclamp_min_show,
- .write = cpu_uclamp_min_write,
- },
- {
- .name = "uclamp.max",
- .flags = CFTYPE_NOT_ON_ROOT,
- .seq_show = cpu_uclamp_max_show,
- .write = cpu_uclamp_max_write,
- },
- {
- .name = "uclamp.latency_sensitive",
- .flags = CFTYPE_NOT_ON_ROOT,
- .read_u64 = cpu_uclamp_ls_read_u64,
- .write_u64 = cpu_uclamp_ls_write_u64,
- },
- #endif
- { } /* terminate */
- };
- struct cgroup_subsys cpu_cgrp_subsys = {
- .css_alloc = cpu_cgroup_css_alloc,
- .css_online = cpu_cgroup_css_online,
- .css_released = cpu_cgroup_css_released,
- .css_free = cpu_cgroup_css_free,
- .css_extra_stat_show = cpu_extra_stat_show,
- .fork = cpu_cgroup_fork,
- .can_attach = cpu_cgroup_can_attach,
- .attach = cpu_cgroup_attach,
- .legacy_cftypes = cpu_legacy_files,
- .dfl_cftypes = cpu_files,
- .early_init = true,
- .threaded = true,
- };
- #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));
- }
- /*
- * Nice levels are multiplicative, with a gentle 10% change for every
- * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
- * nice 1, it will get ~10% less CPU time than another CPU-bound task
- * that remained on nice 0.
- *
- * The "10% effect" is relative and cumulative: from _any_ nice level,
- * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
- * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
- * If a task goes up by ~10% and another task goes down by ~10% then
- * the relative distance between them is ~25%.)
- */
- const int sched_prio_to_weight[40] = {
- /* -20 */ 88761, 71755, 56483, 46273, 36291,
- /* -15 */ 29154, 23254, 18705, 14949, 11916,
- /* -10 */ 9548, 7620, 6100, 4904, 3906,
- /* -5 */ 3121, 2501, 1991, 1586, 1277,
- /* 0 */ 1024, 820, 655, 526, 423,
- /* 5 */ 335, 272, 215, 172, 137,
- /* 10 */ 110, 87, 70, 56, 45,
- /* 15 */ 36, 29, 23, 18, 15,
- };
- /*
- * Inverse (2^32/x) values of the sched_prio_to_weight[] array, precalculated.
- *
- * In cases where the weight does not change often, we can use the
- * precalculated inverse to speed up arithmetics by turning divisions
- * into multiplications:
- */
- const u32 sched_prio_to_wmult[40] = {
- /* -20 */ 48388, 59856, 76040, 92818, 118348,
- /* -15 */ 147320, 184698, 229616, 287308, 360437,
- /* -10 */ 449829, 563644, 704093, 875809, 1099582,
- /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
- /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
- /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
- /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
- /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
- };
- void call_trace_sched_update_nr_running(struct rq *rq, int count)
- {
- trace_sched_update_nr_running_tp(rq, count);
- }
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