<idle>-0 3d.h4 1us+: 0:120:R + [003] 2448: 94:R sleep
<idle>-0 3d.h4 2us : ttwu_do_activate.constprop.87 <-try_to_wake_up
<idle>-0 3d.h3 3us : check_preempt_curr <-ttwu_do_wakeup
- <idle>-0 3d.h3 3us : resched_task <-check_preempt_curr
+ <idle>-0 3d.h3 3us : resched_curr <-check_preempt_curr
<idle>-0 3dNh3 4us : task_woken_rt <-ttwu_do_wakeup
<idle>-0 3dNh3 4us : _raw_spin_unlock <-try_to_wake_up
<idle>-0 3dNh3 4us : sub_preempt_count <-_raw_spin_unlock
#define DEFINE_IRQ_WORK(name, _f) struct irq_work name = { .func = (_f), }
bool irq_work_queue(struct irq_work *work);
+
+#ifdef CONFIG_SMP
+bool irq_work_queue_on(struct irq_work *work, int cpu);
+#endif
+
void irq_work_run(void);
void irq_work_sync(struct irq_work *work);
struct rb_node *pi_waiters_leftmost;
/* Deadlock detection and priority inheritance handling */
struct rt_mutex_waiter *pi_blocked_on;
- /* Top pi_waiters task */
- struct task_struct *pi_top_task;
#endif
#ifdef CONFIG_DEBUG_MUTEXES
/*
* Polling state must be visible before we test NEED_RESCHED,
- * paired by resched_task()
+ * paired by resched_curr()
*/
smp_mb__after_atomic();
/*
* Polling state must be visible before we test NEED_RESCHED,
- * paired by resched_task()
+ * paired by resched_curr()
*/
smp_mb__after_atomic();
* TIF_NEED_RESCHED and the IPI handler, scheduler_ipi(), will also
* fold.
*/
- smp_mb(); /* paired with resched_task() */
+ smp_mb(); /* paired with resched_curr() */
preempt_fold_need_resched();
}
extern void tick_nohz_init(void);
extern void __tick_nohz_full_check(void);
-extern void tick_nohz_full_kick(void);
+extern void tick_nohz_full_kick_cpu(int cpu);
+
+static inline void tick_nohz_full_kick(void)
+{
+ tick_nohz_full_kick_cpu(smp_processor_id());
+}
+
extern void tick_nohz_full_kick_all(void);
extern void __tick_nohz_task_switch(struct task_struct *tsk);
#else
static inline bool tick_nohz_full_enabled(void) { return false; }
static inline bool tick_nohz_full_cpu(int cpu) { return false; }
static inline void __tick_nohz_full_check(void) { }
+static inline void tick_nohz_full_kick_cpu(int cpu) { }
static inline void tick_nohz_full_kick(void) { }
static inline void tick_nohz_full_kick_all(void) { }
static inline void __tick_nohz_task_switch(struct task_struct *tsk) { }
rcu_read_unlock();
}
-static inline void check_for_tasks(int cpu)
+static inline void check_for_tasks(int dead_cpu)
{
- struct task_struct *p;
- cputime_t utime, stime;
+ struct task_struct *g, *p;
- write_lock_irq(&tasklist_lock);
- for_each_process(p) {
- task_cputime(p, &utime, &stime);
- if (task_cpu(p) == cpu && p->state == TASK_RUNNING &&
- (utime || stime))
- pr_warn("Task %s (pid = %d) is on cpu %d (state = %ld, flags = %x)\n",
- p->comm, task_pid_nr(p), cpu,
- p->state, p->flags);
- }
- write_unlock_irq(&tasklist_lock);
+ read_lock_irq(&tasklist_lock);
+ do_each_thread(g, p) {
+ if (!p->on_rq)
+ continue;
+ /*
+ * We do the check with unlocked task_rq(p)->lock.
+ * Order the reading to do not warn about a task,
+ * which was running on this cpu in the past, and
+ * it's just been woken on another cpu.
+ */
+ rmb();
+ if (task_cpu(p) != dead_cpu)
+ continue;
+
+ pr_warn("Task %s (pid=%d) is on cpu %d (state=%ld, flags=%x)\n",
+ p->comm, task_pid_nr(p), dead_cpu, p->state, p->flags);
+ } while_each_thread(g, p);
+ read_unlock_irq(&tasklist_lock);
}
struct take_cpu_down_param {
p->pi_waiters = RB_ROOT;
p->pi_waiters_leftmost = NULL;
p->pi_blocked_on = NULL;
- p->pi_top_task = NULL;
#endif
}
#include <linux/tick.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
+#include <linux/smp.h>
#include <asm/processor.h>
-static DEFINE_PER_CPU(struct llist_head, irq_work_list);
-static DEFINE_PER_CPU(int, irq_work_raised);
+static DEFINE_PER_CPU(struct llist_head, raised_list);
+static DEFINE_PER_CPU(struct llist_head, lazy_list);
/*
* Claim the entry so that no one else will poke at it.
*/
}
+#ifdef CONFIG_SMP
/*
- * Enqueue the irq_work @entry unless it's already pending
+ * Enqueue the irq_work @work on @cpu unless it's already pending
* somewhere.
*
* Can be re-enqueued while the callback is still in progress.
*/
+bool irq_work_queue_on(struct irq_work *work, int cpu)
+{
+ /* All work should have been flushed before going offline */
+ WARN_ON_ONCE(cpu_is_offline(cpu));
+
+ /* Arch remote IPI send/receive backend aren't NMI safe */
+ WARN_ON_ONCE(in_nmi());
+
+ /* Only queue if not already pending */
+ if (!irq_work_claim(work))
+ return false;
+
+ if (llist_add(&work->llnode, &per_cpu(raised_list, cpu)))
+ arch_send_call_function_single_ipi(cpu);
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(irq_work_queue_on);
+#endif
+
+/* Enqueue the irq work @work on the current CPU */
bool irq_work_queue(struct irq_work *work)
{
/* Only queue if not already pending */
/* Queue the entry and raise the IPI if needed. */
preempt_disable();
- llist_add(&work->llnode, &__get_cpu_var(irq_work_list));
-
- /*
- * If the work is not "lazy" or the tick is stopped, raise the irq
- * work interrupt (if supported by the arch), otherwise, just wait
- * for the next tick.
- */
- if (!(work->flags & IRQ_WORK_LAZY) || tick_nohz_tick_stopped()) {
- if (!this_cpu_cmpxchg(irq_work_raised, 0, 1))
+ /* If the work is "lazy", handle it from next tick if any */
+ if (work->flags & IRQ_WORK_LAZY) {
+ if (llist_add(&work->llnode, &__get_cpu_var(lazy_list)) &&
+ tick_nohz_tick_stopped())
+ arch_irq_work_raise();
+ } else {
+ if (llist_add(&work->llnode, &__get_cpu_var(raised_list)))
arch_irq_work_raise();
}
bool irq_work_needs_cpu(void)
{
- struct llist_head *this_list;
+ struct llist_head *raised, *lazy;
- this_list = &__get_cpu_var(irq_work_list);
- if (llist_empty(this_list))
+ raised = &__get_cpu_var(raised_list);
+ lazy = &__get_cpu_var(lazy_list);
+ if (llist_empty(raised) && llist_empty(lazy))
return false;
/* All work should have been flushed before going offline */
return true;
}
-static void __irq_work_run(void)
+static void irq_work_run_list(struct llist_head *list)
{
unsigned long flags;
struct irq_work *work;
- struct llist_head *this_list;
struct llist_node *llnode;
+ BUG_ON(!irqs_disabled());
- /*
- * Reset the "raised" state right before we check the list because
- * an NMI may enqueue after we find the list empty from the runner.
- */
- __this_cpu_write(irq_work_raised, 0);
- barrier();
-
- this_list = &__get_cpu_var(irq_work_list);
- if (llist_empty(this_list))
+ if (llist_empty(list))
return;
- BUG_ON(!irqs_disabled());
-
- llnode = llist_del_all(this_list);
+ llnode = llist_del_all(list);
while (llnode != NULL) {
work = llist_entry(llnode, struct irq_work, llnode);
}
/*
- * Run the irq_work entries on this cpu. Requires to be ran from hardirq
- * context with local IRQs disabled.
+ * hotplug calls this through:
+ * hotplug_cfd() -> flush_smp_call_function_queue()
*/
void irq_work_run(void)
{
- BUG_ON(!in_irq());
- __irq_work_run();
+ irq_work_run_list(&__get_cpu_var(raised_list));
+ irq_work_run_list(&__get_cpu_var(lazy_list));
}
EXPORT_SYMBOL_GPL(irq_work_run);
cpu_relax();
}
EXPORT_SYMBOL_GPL(irq_work_sync);
-
-#ifdef CONFIG_HOTPLUG_CPU
-static int irq_work_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
-{
- long cpu = (long)hcpu;
-
- switch (action) {
- case CPU_DYING:
- /* Called from stop_machine */
- if (WARN_ON_ONCE(cpu != smp_processor_id()))
- break;
- __irq_work_run();
- break;
- default:
- break;
- }
- return NOTIFY_OK;
-}
-
-static struct notifier_block cpu_notify;
-
-static __init int irq_work_init_cpu_notifier(void)
-{
- cpu_notify.notifier_call = irq_work_cpu_notify;
- cpu_notify.priority = 0;
- register_cpu_notifier(&cpu_notify);
- return 0;
-}
-device_initcall(irq_work_init_cpu_notifier);
-
-#endif /* CONFIG_HOTPLUG_CPU */
return;
delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
+ if (delta < 0)
+ return;
rq->clock += delta;
update_rq_clock_task(rq, delta);
}
char buf[64];
char *cmp;
int i;
+ struct inode *inode;
if (cnt > 63)
cnt = 63;
buf[cnt] = 0;
cmp = strstrip(buf);
+ /* Ensure the static_key remains in a consistent state */
+ inode = file_inode(filp);
+ mutex_lock(&inode->i_mutex);
i = sched_feat_set(cmp);
+ mutex_unlock(&inode->i_mutex);
if (i == __SCHED_FEAT_NR)
return -EINVAL;
#endif
/*
- * resched_task - mark a task 'to be rescheduled now'.
+ * 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_task(struct task_struct *p)
+void resched_curr(struct rq *rq)
{
+ struct task_struct *curr = rq->curr;
int cpu;
- lockdep_assert_held(&task_rq(p)->lock);
+ lockdep_assert_held(&rq->lock);
- if (test_tsk_need_resched(p))
+ if (test_tsk_need_resched(curr))
return;
- cpu = task_cpu(p);
+ cpu = cpu_of(rq);
if (cpu == smp_processor_id()) {
- set_tsk_need_resched(p);
+ set_tsk_need_resched(curr);
set_preempt_need_resched();
return;
}
- if (set_nr_and_not_polling(p))
+ if (set_nr_and_not_polling(curr))
smp_send_reschedule(cpu);
else
trace_sched_wake_idle_without_ipi(cpu);
if (!raw_spin_trylock_irqsave(&rq->lock, flags))
return;
- resched_task(cpu_curr(cpu));
+ resched_curr(rq);
raw_spin_unlock_irqrestore(&rq->lock, flags);
}
static bool wake_up_full_nohz_cpu(int cpu)
{
+ /*
+ * We just need the target to call irq_exit() and re-evaluate
+ * the next tick. The nohz full kick at least implies that.
+ * If needed we can still optimize that later with an
+ * empty IRQ.
+ */
if (tick_nohz_full_cpu(cpu)) {
if (cpu != smp_processor_id() ||
tick_nohz_tick_stopped())
- smp_send_reschedule(cpu);
+ tick_nohz_full_kick_cpu(cpu);
return true;
}
#ifdef CONFIG_NO_HZ_FULL
bool sched_can_stop_tick(void)
{
- struct rq *rq;
-
- rq = this_rq();
-
- /* Make sure rq->nr_running update is visible after the IPI */
- smp_rmb();
-
- /* More than one running task need preemption */
- if (rq->nr_running > 1)
- return false;
+ /*
+ * More than one running task need preemption.
+ * nr_running update is assumed to be visible
+ * after IPI is sent from wakers.
+ */
+ if (this_rq()->nr_running > 1)
+ return false;
- return true;
+ return true;
}
#endif /* CONFIG_NO_HZ_FULL */
if (class == rq->curr->sched_class)
break;
if (class == p->sched_class) {
- resched_task(rq->curr);
+ resched_curr(rq);
break;
}
}
*/
preempt_fold_need_resched();
- if (llist_empty(&this_rq()->wake_list)
- && !tick_nohz_full_cpu(smp_processor_id())
- && !got_nohz_idle_kick())
+ if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick())
return;
/*
* somewhat pessimize the simple resched case.
*/
irq_enter();
- tick_nohz_full_check();
sched_ttwu_pending();
/*
{
u64 ns = 0;
- if (task_current(rq, p)) {
+ /*
+ * 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) && p->on_rq) {
update_rq_clock(rq);
ns = rq_clock_task(rq) - p->se.exec_start;
if ((s64)ns < 0)
* 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)
+ if (!p->on_cpu || !p->on_rq)
return p->se.sum_exec_runtime;
#endif
}
trace_sched_pi_setprio(p, prio);
- p->pi_top_task = rt_mutex_get_top_task(p);
oldprio = p->prio;
prev_class = p->sched_class;
on_rq = p->on_rq;
* running task
*/
if (dl_prio(prio)) {
- if (!dl_prio(p->normal_prio) || (p->pi_top_task &&
- dl_entity_preempt(&p->pi_top_task->dl, &p->dl))) {
+ struct task_struct *pi_task = rt_mutex_get_top_task(p);
+ if (!dl_prio(p->normal_prio) ||
+ (pi_task && dl_entity_preempt(&pi_task->dl, &p->dl))) {
p->dl.dl_boosted = 1;
p->dl.dl_throttled = 0;
enqueue_flag = ENQUEUE_REPLENISH;
* lowered its priority, then reschedule its CPU:
*/
if (delta < 0 || (delta > 0 && task_running(rq, p)))
- resched_task(rq->curr);
+ resched_curr(rq);
}
out_unlock:
task_rq_unlock(rq, p, &flags);
* fairness.
*/
if (preempt && rq != p_rq)
- resched_task(p_rq->curr);
+ resched_curr(p_rq);
}
out_unlock:
__setscheduler(rq, p, &attr);
if (on_rq) {
enqueue_task(rq, p, 0);
- resched_task(rq->curr);
+ resched_curr(rq);
}
check_class_changed(rq, p, prev_class, old_prio);
if (period > max_cfs_quota_period)
return -EINVAL;
+ /*
+ * Prevent race between setting of cfs_rq->runtime_enabled and
+ * unthrottle_offline_cfs_rqs().
+ */
+ get_online_cpus();
mutex_lock(&cfs_constraints_mutex);
ret = __cfs_schedulable(tg, period, quota);
if (ret)
}
raw_spin_unlock_irq(&cfs_b->lock);
- for_each_possible_cpu(i) {
+ for_each_online_cpu(i) {
struct cfs_rq *cfs_rq = tg->cfs_rq[i];
struct rq *rq = cfs_rq->rq;
cfs_bandwidth_usage_dec();
out_unlock:
mutex_unlock(&cfs_constraints_mutex);
+ put_online_cpus();
return ret;
}
* the overrunning entity can't interfere with other entity in the system and
* can't make them miss their deadlines. Reasons why this kind of overruns
* could happen are, typically, a entity voluntarily trying to overcome its
- * runtime, or it just underestimated it during sched_setscheduler_ex().
+ * runtime, or it just underestimated it during sched_setattr().
*/
static void replenish_dl_entity(struct sched_dl_entity *dl_se,
struct sched_dl_entity *pi_se)
if (task_has_dl_policy(rq->curr))
check_preempt_curr_dl(rq, p, 0);
else
- resched_task(rq->curr);
+ resched_curr(rq);
#ifdef CONFIG_SMP
/*
* Queueing this task back might have overloaded rq,
enqueue_task_dl(rq, curr, ENQUEUE_REPLENISH);
if (!is_leftmost(curr, &rq->dl))
- resched_task(curr);
+ resched_curr(rq);
}
/*
cpudl_find(&rq->rd->cpudl, p, NULL) != -1)
return;
- resched_task(rq->curr);
+ resched_curr(rq);
}
static int pull_dl_task(struct rq *this_rq);
int flags)
{
if (dl_entity_preempt(&p->dl, &rq->curr->dl)) {
- resched_task(rq->curr);
+ resched_curr(rq);
return;
}
if (dl_task(rq->curr) &&
dl_time_before(next_task->dl.deadline, rq->curr->dl.deadline) &&
rq->curr->nr_cpus_allowed > 1) {
- resched_task(rq->curr);
+ resched_curr(rq);
return 0;
}
set_task_cpu(next_task, later_rq->cpu);
activate_task(later_rq, next_task, 0);
- resched_task(later_rq->curr);
+ resched_curr(later_rq);
double_unlock_balance(rq, later_rq);
*/
if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline) &&
rq->curr == p)
- resched_task(p);
+ resched_curr(rq);
#else
/*
* Again, we don't know if p has a earlier
* or later deadline, so let's blindly set a
* (maybe not needed) rescheduling point.
*/
- resched_task(p);
+ resched_curr(rq);
#endif /* CONFIG_SMP */
} else
switched_to_dl(rq, p);
if (!cpus)
return;
- ns->load = (ns->load * SCHED_CAPACITY_SCALE) / ns->compute_capacity;
ns->task_capacity =
DIV_ROUND_CLOSEST(ns->compute_capacity, SCHED_CAPACITY_SCALE);
ns->has_free_capacity = (ns->nr_running < ns->task_capacity);
env->best_cpu = env->dst_cpu;
}
-static bool load_too_imbalanced(long orig_src_load, long orig_dst_load,
- long src_load, long dst_load,
+static bool load_too_imbalanced(long src_load, long dst_load,
struct task_numa_env *env)
{
long imb, old_imb;
+ long orig_src_load, orig_dst_load;
+ long src_capacity, dst_capacity;
+
+ /*
+ * The load is corrected for the CPU capacity available on each node.
+ *
+ * src_load dst_load
+ * ------------ vs ---------
+ * src_capacity dst_capacity
+ */
+ src_capacity = env->src_stats.compute_capacity;
+ dst_capacity = env->dst_stats.compute_capacity;
/* We care about the slope of the imbalance, not the direction. */
if (dst_load < src_load)
swap(dst_load, src_load);
/* Is the difference below the threshold? */
- imb = dst_load * 100 - src_load * env->imbalance_pct;
+ imb = dst_load * src_capacity * 100 -
+ src_load * dst_capacity * env->imbalance_pct;
if (imb <= 0)
return false;
* The imbalance is above the allowed threshold.
* Compare it with the old imbalance.
*/
+ orig_src_load = env->src_stats.load;
+ orig_dst_load = env->dst_stats.load;
+
if (orig_dst_load < orig_src_load)
swap(orig_dst_load, orig_src_load);
- old_imb = orig_dst_load * 100 - orig_src_load * env->imbalance_pct;
+ old_imb = orig_dst_load * src_capacity * 100 -
+ orig_src_load * dst_capacity * env->imbalance_pct;
/* Would this change make things worse? */
return (imb > old_imb);
struct rq *src_rq = cpu_rq(env->src_cpu);
struct rq *dst_rq = cpu_rq(env->dst_cpu);
struct task_struct *cur;
- long orig_src_load, src_load;
- long orig_dst_load, dst_load;
+ long src_load, dst_load;
long load;
- long imp = (groupimp > 0) ? groupimp : taskimp;
+ long imp = env->p->numa_group ? groupimp : taskimp;
+ long moveimp = imp;
rcu_read_lock();
cur = ACCESS_ONCE(dst_rq->curr);
* itself (not part of a group), use the task weight
* instead.
*/
- if (env->p->numa_group)
- imp = groupimp;
- else
- imp = taskimp;
-
if (cur->numa_group)
imp += group_weight(cur, env->src_nid) -
group_weight(cur, env->dst_nid);
}
}
- if (imp < env->best_imp)
+ if (imp <= env->best_imp && moveimp <= env->best_imp)
goto unlock;
if (!cur) {
}
/* Balance doesn't matter much if we're running a task per cpu */
- if (src_rq->nr_running == 1 && dst_rq->nr_running == 1)
+ if (imp > env->best_imp && src_rq->nr_running == 1 &&
+ dst_rq->nr_running == 1)
goto assign;
/*
* In the overloaded case, try and keep the load balanced.
*/
balance:
- orig_dst_load = env->dst_stats.load;
- orig_src_load = env->src_stats.load;
-
- /* XXX missing capacity terms */
load = task_h_load(env->p);
- dst_load = orig_dst_load + load;
- src_load = orig_src_load - load;
+ dst_load = env->dst_stats.load + load;
+ src_load = env->src_stats.load - load;
+
+ if (moveimp > imp && moveimp > env->best_imp) {
+ /*
+ * If the improvement from just moving env->p direction is
+ * better than swapping tasks around, check if a move is
+ * possible. Store a slightly smaller score than moveimp,
+ * so an actually idle CPU will win.
+ */
+ if (!load_too_imbalanced(src_load, dst_load, env)) {
+ imp = moveimp - 1;
+ cur = NULL;
+ goto assign;
+ }
+ }
+
+ if (imp <= env->best_imp)
+ goto unlock;
if (cur) {
load = task_h_load(cur);
src_load += load;
}
- if (load_too_imbalanced(orig_src_load, orig_dst_load,
- src_load, dst_load, env))
+ if (load_too_imbalanced(src_load, dst_load, env))
goto unlock;
assign:
groupimp = group_weight(p, env.dst_nid) - groupweight;
update_numa_stats(&env.dst_stats, env.dst_nid);
- /* If the preferred nid has free capacity, try to use it. */
- if (env.dst_stats.has_free_capacity)
- task_numa_find_cpu(&env, taskimp, groupimp);
+ /* Try to find a spot on the preferred nid. */
+ task_numa_find_cpu(&env, taskimp, groupimp);
/* No space available on the preferred nid. Look elsewhere. */
if (env.best_cpu == -1) {
}
}
- /* No better CPU than the current one was found. */
- if (env.best_cpu == -1)
- return -EAGAIN;
-
/*
* If the task is part of a workload that spans multiple NUMA nodes,
* and is migrating into one of the workload's active nodes, remember
* A task that migrated to a second choice node will be better off
* trying for a better one later. Do not set the preferred node here.
*/
- if (p->numa_group && node_isset(env.dst_nid, p->numa_group->active_nodes))
- sched_setnuma(p, env.dst_nid);
+ if (p->numa_group) {
+ if (env.best_cpu == -1)
+ nid = env.src_nid;
+ else
+ nid = env.dst_nid;
+
+ if (node_isset(nid, p->numa_group->active_nodes))
+ sched_setnuma(p, env.dst_nid);
+ }
+
+ /* No better CPU than the current one was found. */
+ if (env.best_cpu == -1)
+ return -EAGAIN;
/*
* Reset the scan period if the task is being rescheduled on an
/*
* When adapting the scan rate, the period is divided into NUMA_PERIOD_SLOTS
* increments. The more local the fault statistics are, the higher the scan
- * period will be for the next scan window. If local/remote ratio is below
- * NUMA_PERIOD_THRESHOLD (where range of ratio is 1..NUMA_PERIOD_SLOTS) the
- * scan period will decrease
+ * period will be for the next scan window. If local/(local+remote) ratio is
+ * below NUMA_PERIOD_THRESHOLD (where range of ratio is 1..NUMA_PERIOD_SLOTS)
+ * the scan period will decrease. Aim for 70% local accesses.
*/
#define NUMA_PERIOD_SLOTS 10
-#define NUMA_PERIOD_THRESHOLD 3
+#define NUMA_PERIOD_THRESHOLD 7
/*
* Increase the scan period (slow down scanning) if the majority of
if (p->numa_group) {
update_numa_active_node_mask(p->numa_group);
- /*
- * If the preferred task and group nids are different,
- * iterate over the nodes again to find the best place.
- */
- if (max_nid != max_group_nid) {
- unsigned long weight, max_weight = 0;
-
- for_each_online_node(nid) {
- weight = task_weight(p, nid) + group_weight(p, nid);
- if (weight > max_weight) {
- max_weight = weight;
- max_nid = nid;
- }
- }
- }
-
spin_unlock_irq(group_lock);
+ max_nid = max_group_nid;
}
- /* Preferred node as the node with the most faults */
- if (max_faults && max_nid != p->numa_preferred_nid) {
- /* Update the preferred nid and migrate task if possible */
- sched_setnuma(p, max_nid);
- numa_migrate_preferred(p);
+ if (max_faults) {
+ /* Set the new preferred node */
+ if (max_nid != p->numa_preferred_nid)
+ sched_setnuma(p, max_nid);
+
+ if (task_node(p) != p->numa_preferred_nid)
+ numa_migrate_preferred(p);
}
}
ideal_runtime = sched_slice(cfs_rq, curr);
delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
if (delta_exec > ideal_runtime) {
- resched_task(rq_of(cfs_rq)->curr);
+ resched_curr(rq_of(cfs_rq));
/*
* The current task ran long enough, ensure it doesn't get
* re-elected due to buddy favours.
return;
if (delta > ideal_runtime)
- resched_task(rq_of(cfs_rq)->curr);
+ resched_curr(rq_of(cfs_rq));
}
static void
* validating it and just reschedule.
*/
if (queued) {
- resched_task(rq_of(cfs_rq)->curr);
+ resched_curr(rq_of(cfs_rq));
return;
}
/*
* hierarchy can be throttled
*/
if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr))
- resched_task(rq_of(cfs_rq)->curr);
+ resched_curr(rq_of(cfs_rq));
}
static __always_inline
cfs_rq->throttled = 1;
cfs_rq->throttled_clock = rq_clock(rq);
raw_spin_lock(&cfs_b->lock);
- list_add_tail_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq);
+ /*
+ * Add to the _head_ of the list, so that an already-started
+ * distribute_cfs_runtime will not see us
+ */
+ list_add_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq);
if (!cfs_b->timer_active)
__start_cfs_bandwidth(cfs_b, false);
raw_spin_unlock(&cfs_b->lock);
/* determine whether we need to wake up potentially idle cpu */
if (rq->curr == rq->idle && rq->cfs.nr_running)
- resched_task(rq->curr);
+ resched_curr(rq);
}
static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b,
u64 remaining, u64 expires)
{
struct cfs_rq *cfs_rq;
- u64 runtime = remaining;
+ u64 runtime;
+ u64 starting_runtime = remaining;
rcu_read_lock();
list_for_each_entry_rcu(cfs_rq, &cfs_b->throttled_cfs_rq,
}
rcu_read_unlock();
- return remaining;
+ return starting_runtime - remaining;
}
/*
/* account preceding periods in which throttling occurred */
cfs_b->nr_throttled += overrun;
- /*
- * There are throttled entities so we must first use the new bandwidth
- * to unthrottle them before making it generally available. This
- * ensures that all existing debts will be paid before a new cfs_rq is
- * allowed to run.
- */
- runtime = cfs_b->runtime;
runtime_expires = cfs_b->runtime_expires;
- cfs_b->runtime = 0;
/*
- * This check is repeated as we are holding onto the new bandwidth
- * while we unthrottle. This can potentially race with an unthrottled
- * group trying to acquire new bandwidth from the global pool.
+ * This check is repeated as we are holding onto the new bandwidth while
+ * we unthrottle. This can potentially race with an unthrottled group
+ * trying to acquire new bandwidth from the global pool. This can result
+ * in us over-using our runtime if it is all used during this loop, but
+ * only by limited amounts in that extreme case.
*/
- while (throttled && runtime > 0) {
+ while (throttled && cfs_b->runtime > 0) {
+ runtime = cfs_b->runtime;
raw_spin_unlock(&cfs_b->lock);
/* we can't nest cfs_b->lock while distributing bandwidth */
runtime = distribute_cfs_runtime(cfs_b, runtime,
raw_spin_lock(&cfs_b->lock);
throttled = !list_empty(&cfs_b->throttled_cfs_rq);
+
+ cfs_b->runtime -= min(runtime, cfs_b->runtime);
}
- /* return (any) remaining runtime */
- cfs_b->runtime = runtime;
/*
* While we are ensured activity in the period following an
* unthrottle, this also covers the case in which the new bandwidth is
return;
}
- if (cfs_b->quota != RUNTIME_INF && cfs_b->runtime > slice) {
+ if (cfs_b->quota != RUNTIME_INF && cfs_b->runtime > slice)
runtime = cfs_b->runtime;
- cfs_b->runtime = 0;
- }
+
expires = cfs_b->runtime_expires;
raw_spin_unlock(&cfs_b->lock);
raw_spin_lock(&cfs_b->lock);
if (expires == cfs_b->runtime_expires)
- cfs_b->runtime = runtime;
+ cfs_b->runtime -= min(runtime, cfs_b->runtime);
raw_spin_unlock(&cfs_b->lock);
}
hrtimer_cancel(&cfs_b->slack_timer);
}
+static void __maybe_unused update_runtime_enabled(struct rq *rq)
+{
+ struct cfs_rq *cfs_rq;
+
+ for_each_leaf_cfs_rq(rq, cfs_rq) {
+ struct cfs_bandwidth *cfs_b = &cfs_rq->tg->cfs_bandwidth;
+
+ raw_spin_lock(&cfs_b->lock);
+ cfs_rq->runtime_enabled = cfs_b->quota != RUNTIME_INF;
+ raw_spin_unlock(&cfs_b->lock);
+ }
+}
+
static void __maybe_unused unthrottle_offline_cfs_rqs(struct rq *rq)
{
struct cfs_rq *cfs_rq;
* there's some valid quota amount
*/
cfs_rq->runtime_remaining = 1;
+ /*
+ * Offline rq is schedulable till cpu is completely disabled
+ * in take_cpu_down(), so we prevent new cfs throttling here.
+ */
+ cfs_rq->runtime_enabled = 0;
+
if (cfs_rq_throttled(cfs_rq))
unthrottle_cfs_rq(cfs_rq);
}
return NULL;
}
static inline void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
+static inline void update_runtime_enabled(struct rq *rq) {}
static inline void unthrottle_offline_cfs_rqs(struct rq *rq) {}
#endif /* CONFIG_CFS_BANDWIDTH */
if (delta < 0) {
if (rq->curr == p)
- resched_task(p);
+ resched_curr(rq);
return;
}
return;
preempt:
- resched_task(curr);
+ resched_curr(rq);
/*
* Only set the backward buddy when the current task is still
* on the rq. This can happen when a wakeup gets interleaved
/*
* Is this task likely cache-hot:
*/
-static int
-task_hot(struct task_struct *p, u64 now)
+static int task_hot(struct task_struct *p, struct lb_env *env)
{
s64 delta;
/*
* Buddy candidates are cache hot:
*/
- if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running &&
+ if (sched_feat(CACHE_HOT_BUDDY) && env->dst_rq->nr_running &&
(&p->se == cfs_rq_of(&p->se)->next ||
&p->se == cfs_rq_of(&p->se)->last))
return 1;
if (sysctl_sched_migration_cost == 0)
return 0;
- delta = now - p->se.exec_start;
+ delta = rq_clock_task(env->src_rq) - p->se.exec_start;
return delta < (s64)sysctl_sched_migration_cost;
}
* 2) task is cache cold, or
* 3) too many balance attempts have failed.
*/
- tsk_cache_hot = task_hot(p, rq_clock_task(env->src_rq));
+ tsk_cache_hot = task_hot(p, env);
if (!tsk_cache_hot)
tsk_cache_hot = migrate_degrades_locality(p, env);
*/
static inline void update_sg_lb_stats(struct lb_env *env,
struct sched_group *group, int load_idx,
- int local_group, struct sg_lb_stats *sgs)
+ int local_group, struct sg_lb_stats *sgs,
+ bool *overload)
{
unsigned long load;
int i;
sgs->group_load += load;
sgs->sum_nr_running += rq->nr_running;
+
+ if (rq->nr_running > 1)
+ *overload = true;
+
#ifdef CONFIG_NUMA_BALANCING
sgs->nr_numa_running += rq->nr_numa_running;
sgs->nr_preferred_running += rq->nr_preferred_running;
struct sched_group *sg = env->sd->groups;
struct sg_lb_stats tmp_sgs;
int load_idx, prefer_sibling = 0;
+ bool overload = false;
if (child && child->flags & SD_PREFER_SIBLING)
prefer_sibling = 1;
update_group_capacity(env->sd, env->dst_cpu);
}
- update_sg_lb_stats(env, sg, load_idx, local_group, sgs);
+ update_sg_lb_stats(env, sg, load_idx, local_group, sgs,
+ &overload);
if (local_group)
goto next_group;
if (env->sd->flags & SD_NUMA)
env->fbq_type = fbq_classify_group(&sds->busiest_stat);
+
+ if (!env->sd->parent) {
+ /* update overload indicator if we are at root domain */
+ if (env->dst_rq->rd->overload != overload)
+ env->dst_rq->rd->overload = overload;
+ }
+
}
/**
*/
this_rq->idle_stamp = rq_clock(this_rq);
- if (this_rq->avg_idle < sysctl_sched_migration_cost) {
+ if (this_rq->avg_idle < sysctl_sched_migration_cost ||
+ !this_rq->rd->overload) {
rcu_read_lock();
sd = rcu_dereference_check_sched_domain(this_rq->sd);
if (sd)
static void rq_online_fair(struct rq *rq)
{
update_sysctl();
+
+ update_runtime_enabled(rq);
}
static void rq_offline_fair(struct rq *rq)
* 'current' within the tree based on its new key value.
*/
swap(curr->vruntime, se->vruntime);
- resched_task(rq->curr);
+ resched_curr(rq);
}
se->vruntime -= cfs_rq->min_vruntime;
*/
if (rq->curr == p) {
if (p->prio > oldprio)
- resched_task(rq->curr);
+ resched_curr(rq);
} else
check_preempt_curr(rq, p, 0);
}
* if we can still preempt the current task.
*/
if (rq->curr == p)
- resched_task(rq->curr);
+ resched_curr(rq);
else
check_preempt_curr(rq, p, 0);
}
struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
int next_state, entered_state;
- bool broadcast;
+ unsigned int broadcast;
/*
* Check if the idle task must be rescheduled. If it is the
goto exit_idle;
}
- broadcast = !!(drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP);
+ broadcast = drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP;
/*
* Tell the time framework to switch to a broadcast timer
*/
static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p, int flags)
{
- resched_task(rq->idle);
+ resched_curr(rq);
}
static struct task_struct *
static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
{
struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
+ struct rq *rq = rq_of_rt_rq(rt_rq);
struct sched_rt_entity *rt_se;
- int cpu = cpu_of(rq_of_rt_rq(rt_rq));
+ int cpu = cpu_of(rq);
rt_se = rt_rq->tg->rt_se[cpu];
enqueue_rt_entity(rt_se, false);
if (rt_rq->highest_prio.curr < curr->prio)
- resched_task(curr);
+ resched_curr(rq);
}
}
return;
enqueue_top_rt_rq(rt_rq);
- resched_task(rq->curr);
+ resched_curr(rq);
}
static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
rt_rq->rt_throttled = 0;
raw_spin_unlock(&rt_rq->rt_runtime_lock);
raw_spin_unlock(&rt_b->rt_runtime_lock);
+
+ /* Make rt_rq available for pick_next_task() */
+ sched_rt_rq_enqueue(rt_rq);
}
}
raw_spin_lock(&rt_rq->rt_runtime_lock);
rt_rq->rt_time += delta_exec;
if (sched_rt_runtime_exceeded(rt_rq))
- resched_task(curr);
+ resched_curr(rq);
raw_spin_unlock(&rt_rq->rt_runtime_lock);
}
}
* to try and push current away:
*/
requeue_task_rt(rq, p, 1);
- resched_task(rq->curr);
+ resched_curr(rq);
}
#endif /* CONFIG_SMP */
static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flags)
{
if (p->prio < rq->curr->prio) {
- resched_task(rq->curr);
+ resched_curr(rq);
return;
}
* just reschedule current.
*/
if (unlikely(next_task->prio < rq->curr->prio)) {
- resched_task(rq->curr);
+ resched_curr(rq);
return 0;
}
activate_task(lowest_rq, next_task, 0);
ret = 1;
- resched_task(lowest_rq->curr);
+ resched_curr(lowest_rq);
double_unlock_balance(rq, lowest_rq);
return;
if (pull_rt_task(rq))
- resched_task(rq->curr);
+ resched_curr(rq);
}
void __init init_sched_rt_class(void)
check_resched = 0;
#endif /* CONFIG_SMP */
if (check_resched && p->prio < rq->curr->prio)
- resched_task(rq->curr);
+ resched_curr(rq);
}
}
* Only reschedule if p is still on the same runqueue.
*/
if (p->prio > rq->rt.highest_prio.curr && rq->curr == p)
- resched_task(p);
+ resched_curr(rq);
#else
/* For UP simply resched on drop of prio */
if (oldprio < p->prio)
- resched_task(p);
+ resched_curr(rq);
#endif /* CONFIG_SMP */
} else {
/*
* then reschedule.
*/
if (p->prio < rq->curr->prio)
- resched_task(rq->curr);
+ resched_curr(rq);
}
}
cpumask_var_t span;
cpumask_var_t online;
+ /* Indicate more than one runnable task for any CPU */
+ bool overload;
+
/*
* The bit corresponding to a CPU gets set here if such CPU has more
* than one runnable -deadline task (as it is below for RT tasks).
#undef SCHED_FEAT
#if defined(CONFIG_SCHED_DEBUG) && defined(HAVE_JUMP_LABEL)
-static __always_inline bool static_branch__true(struct static_key *key)
-{
- return static_key_true(key); /* Not out of line branch. */
-}
-
-static __always_inline bool static_branch__false(struct static_key *key)
-{
- return static_key_false(key); /* Out of line branch. */
-}
-
#define SCHED_FEAT(name, enabled) \
static __always_inline bool static_branch_##name(struct static_key *key) \
{ \
- return static_branch__##enabled(key); \
+ return static_key_##enabled(key); \
}
#include "features.h"
extern void init_sched_fair_class(void);
extern void init_sched_dl_class(void);
-extern void resched_task(struct task_struct *p);
+extern void resched_curr(struct rq *rq);
extern void resched_cpu(int cpu);
extern struct rt_bandwidth def_rt_bandwidth;
rq->nr_running = prev_nr + count;
-#ifdef CONFIG_NO_HZ_FULL
if (prev_nr < 2 && rq->nr_running >= 2) {
+#ifdef CONFIG_SMP
+ if (!rq->rd->overload)
+ rq->rd->overload = true;
+#endif
+
+#ifdef CONFIG_NO_HZ_FULL
if (tick_nohz_full_cpu(rq->cpu)) {
- /* Order rq->nr_running write against the IPI */
- smp_wmb();
- smp_send_reschedule(rq->cpu);
+ /*
+ * Tick is needed if more than one task runs on a CPU.
+ * Send the target an IPI to kick it out of nohz mode.
+ *
+ * We assume that IPI implies full memory barrier and the
+ * new value of rq->nr_running is visible on reception
+ * from the target.
+ */
+ tick_nohz_full_kick_cpu(rq->cpu);
}
- }
#endif
+ }
}
static inline void sub_nr_running(struct rq *rq, unsigned count)
*
* (C) Jens Axboe <jens.axboe@oracle.com> 2008
*/
+#include <linux/irq_work.h>
#include <linux/rcupdate.h>
#include <linux/rculist.h>
#include <linux/kernel.h>
csd->func(csd->info);
csd_unlock(csd);
}
+
+ /*
+ * Handle irq works queued remotely by irq_work_queue_on().
+ * Smp functions above are typically synchronous so they
+ * better run first since some other CPUs may be busy waiting
+ * for them.
+ */
+ irq_work_run();
}
/*
};
/*
- * Kick the current CPU if it's full dynticks in order to force it to
+ * Kick the CPU if it's full dynticks in order to force it to
* re-evaluate its dependency on the tick and restart it if necessary.
*/
-void tick_nohz_full_kick(void)
+void tick_nohz_full_kick_cpu(int cpu)
{
- if (tick_nohz_full_cpu(smp_processor_id()))
- irq_work_queue(&__get_cpu_var(nohz_full_kick_work));
+ if (!tick_nohz_full_cpu(cpu))
+ return;
+
+ irq_work_queue_on(&per_cpu(nohz_full_kick_work, cpu), cpu);
}
static void nohz_full_kick_ipi(void *info)
projects / linux-beck.git / commitdiff