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Diffstat (limited to 'kernel/sched/core.c')
-rw-r--r--kernel/sched/core.c203
1 files changed, 115 insertions, 88 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index f7402f7eb448..aa5973220ad2 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -817,7 +817,7 @@ static void set_load_weight(struct task_struct *p)
/*
* SCHED_IDLE tasks get minimal weight:
*/
- if (p->policy == SCHED_IDLE) {
+ if (idle_policy(p->policy)) {
load->weight = scale_load(WEIGHT_IDLEPRIO);
load->inv_weight = WMULT_IDLEPRIO;
return;
@@ -827,17 +827,19 @@ static void set_load_weight(struct task_struct *p)
load->inv_weight = prio_to_wmult[prio];
}
-static void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
+static inline void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
{
update_rq_clock(rq);
- sched_info_queued(rq, p);
+ if (!(flags & ENQUEUE_RESTORE))
+ sched_info_queued(rq, p);
p->sched_class->enqueue_task(rq, p, flags);
}
-static void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
+static inline void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
{
update_rq_clock(rq);
- sched_info_dequeued(rq, p);
+ if (!(flags & DEQUEUE_SAVE))
+ sched_info_dequeued(rq, p);
p->sched_class->dequeue_task(rq, p, flags);
}
@@ -1178,7 +1180,7 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
* holding rq->lock.
*/
lockdep_assert_held(&rq->lock);
- dequeue_task(rq, p, 0);
+ dequeue_task(rq, p, DEQUEUE_SAVE);
}
if (running)
put_prev_task(rq, p);
@@ -1188,7 +1190,7 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
if (running)
p->sched_class->set_curr_task(rq);
if (queued)
- enqueue_task(rq, p, 0);
+ enqueue_task(rq, p, ENQUEUE_RESTORE);
}
/*
@@ -1292,7 +1294,7 @@ void set_task_cpu(struct task_struct *p, unsigned int 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->sched_class->migrate_task_rq(p);
p->se.nr_migrations++;
perf_event_task_migrate(p);
}
@@ -1333,12 +1335,16 @@ static int migrate_swap_stop(void *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;
@@ -1574,13 +1580,15 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
goto out;
}
+ /* No more Mr. Nice Guy. */
switch (state) {
case cpuset:
- /* No more Mr. Nice Guy. */
- cpuset_cpus_allowed_fallback(p);
- state = possible;
- break;
-
+ if (IS_ENABLED(CONFIG_CPUSETS)) {
+ cpuset_cpus_allowed_fallback(p);
+ state = possible;
+ break;
+ }
+ /* fall-through */
case possible:
do_set_cpus_allowed(p, cpu_possible_mask);
state = fail;
@@ -1692,7 +1700,7 @@ ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
#endif /* CONFIG_SCHEDSTATS */
}
-static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
+static inline void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
{
activate_task(rq, p, en_flags);
p->on_rq = TASK_ON_RQ_QUEUED;
@@ -2114,23 +2122,17 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
#endif /* CONFIG_NUMA_BALANCING */
}
+DEFINE_STATIC_KEY_FALSE(sched_numa_balancing);
+
#ifdef CONFIG_NUMA_BALANCING
-#ifdef CONFIG_SCHED_DEBUG
+
void set_numabalancing_state(bool enabled)
{
if (enabled)
- sched_feat_set("NUMA");
+ static_branch_enable(&sched_numa_balancing);
else
- sched_feat_set("NO_NUMA");
+ static_branch_disable(&sched_numa_balancing);
}
-#else
-__read_mostly bool numabalancing_enabled;
-
-void set_numabalancing_state(bool enabled)
-{
- numabalancing_enabled = enabled;
-}
-#endif /* CONFIG_SCHED_DEBUG */
#ifdef CONFIG_PROC_SYSCTL
int sysctl_numa_balancing(struct ctl_table *table, int write,
@@ -2138,7 +2140,7 @@ int sysctl_numa_balancing(struct ctl_table *table, int write,
{
struct ctl_table t;
int err;
- int state = numabalancing_enabled;
+ int state = static_branch_likely(&sched_numa_balancing);
if (write && !capable(CAP_SYS_ADMIN))
return -EPERM;
@@ -2349,6 +2351,8 @@ void wake_up_new_task(struct task_struct *p)
struct rq *rq;
raw_spin_lock_irqsave(&p->pi_lock, flags);
+ /* Initialize new task's runnable average */
+ init_entity_runnable_average(&p->se);
#ifdef CONFIG_SMP
/*
* Fork balancing, do it here and not earlier because:
@@ -2358,8 +2362,6 @@ void wake_up_new_task(struct task_struct *p)
set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0));
#endif
- /* Initialize new task's runnable average */
- init_entity_runnable_average(&p->se);
rq = __task_rq_lock(p);
activate_task(rq, p, 0);
p->on_rq = TASK_ON_RQ_QUEUED;
@@ -2483,7 +2485,6 @@ static inline void
prepare_task_switch(struct rq *rq, struct task_struct *prev,
struct task_struct *next)
{
- trace_sched_switch(prev, next);
sched_info_switch(rq, prev, next);
perf_event_task_sched_out(prev, next);
fire_sched_out_preempt_notifiers(prev, next);
@@ -2517,6 +2518,22 @@ static struct rq *finish_task_switch(struct task_struct *prev)
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;
/*
@@ -2601,8 +2618,15 @@ asmlinkage __visible void schedule_tail(struct task_struct *prev)
{
struct rq *rq;
- /* finish_task_switch() drops rq->lock and enables preemtion */
- preempt_disable();
+ /*
+ * 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();
@@ -2960,15 +2984,13 @@ static noinline void __schedule_bug(struct task_struct *prev)
static inline void schedule_debug(struct task_struct *prev)
{
#ifdef CONFIG_SCHED_STACK_END_CHECK
- BUG_ON(unlikely(task_stack_end_corrupted(prev)));
+ BUG_ON(task_stack_end_corrupted(prev));
#endif
- /*
- * Test if we are atomic. Since do_exit() needs to call into
- * schedule() atomically, we ignore that path. Otherwise whine
- * if we are scheduling when we should not.
- */
- if (unlikely(in_atomic_preempt_off() && prev->state != TASK_DEAD))
+
+ 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));
@@ -3054,7 +3076,7 @@ again:
*
* WARNING: must be called with preemption disabled!
*/
-static void __sched __schedule(void)
+static void __sched notrace __schedule(bool preempt)
{
struct task_struct *prev, *next;
unsigned long *switch_count;
@@ -3066,6 +3088,17 @@ static void __sched __schedule(void)
rcu_note_context_switch();
prev = rq->curr;
+ /*
+ * do_exit() calls schedule() with preemption disabled as an exception;
+ * however we must fix that up, otherwise the next task will see an
+ * inconsistent (higher) preempt count.
+ *
+ * It also avoids the below schedule_debug() test from complaining
+ * about this.
+ */
+ if (unlikely(prev->state == TASK_DEAD))
+ preempt_enable_no_resched_notrace();
+
schedule_debug(prev);
if (sched_feat(HRTICK))
@@ -3083,7 +3116,7 @@ static void __sched __schedule(void)
rq->clock_skip_update <<= 1; /* promote REQ to ACT */
switch_count = &prev->nivcsw;
- if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
+ if (!preempt && prev->state) {
if (unlikely(signal_pending_state(prev->state, prev))) {
prev->state = TASK_RUNNING;
} else {
@@ -3119,6 +3152,7 @@ static void __sched __schedule(void)
rq->curr = next;
++*switch_count;
+ trace_sched_switch(preempt, prev, next);
rq = context_switch(rq, prev, next); /* unlocks the rq */
cpu = cpu_of(rq);
} else {
@@ -3148,7 +3182,7 @@ asmlinkage __visible void __sched schedule(void)
sched_submit_work(tsk);
do {
preempt_disable();
- __schedule();
+ __schedule(false);
sched_preempt_enable_no_resched();
} while (need_resched());
}
@@ -3188,9 +3222,9 @@ void __sched schedule_preempt_disabled(void)
static void __sched notrace preempt_schedule_common(void)
{
do {
- preempt_active_enter();
- __schedule();
- preempt_active_exit();
+ preempt_disable_notrace();
+ __schedule(true);
+ preempt_enable_no_resched_notrace();
/*
* Check again in case we missed a preemption opportunity
@@ -3241,24 +3275,17 @@ asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
return;
do {
- /*
- * Use raw __prempt_count() ops that don't call function.
- * We can't call functions before disabling preemption which
- * disarm preemption tracing recursions.
- */
- __preempt_count_add(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET);
- barrier();
+ preempt_disable_notrace();
/*
* 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();
+ __schedule(true);
exception_exit(prev_ctx);
- barrier();
- __preempt_count_sub(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET);
+ preempt_enable_no_resched_notrace();
} while (need_resched());
}
EXPORT_SYMBOL_GPL(preempt_schedule_notrace);
@@ -3281,11 +3308,11 @@ asmlinkage __visible void __sched preempt_schedule_irq(void)
prev_state = exception_enter();
do {
- preempt_active_enter();
+ preempt_disable();
local_irq_enable();
- __schedule();
+ __schedule(true);
local_irq_disable();
- preempt_active_exit();
+ sched_preempt_enable_no_resched();
} while (need_resched());
exception_exit(prev_state);
@@ -3313,7 +3340,7 @@ EXPORT_SYMBOL(default_wake_function);
*/
void rt_mutex_setprio(struct task_struct *p, int prio)
{
- int oldprio, queued, running, enqueue_flag = 0;
+ int oldprio, queued, running, enqueue_flag = ENQUEUE_RESTORE;
struct rq *rq;
const struct sched_class *prev_class;
@@ -3345,7 +3372,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
queued = task_on_rq_queued(p);
running = task_current(rq, p);
if (queued)
- dequeue_task(rq, p, 0);
+ dequeue_task(rq, p, DEQUEUE_SAVE);
if (running)
put_prev_task(rq, p);
@@ -3363,7 +3390,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
if (!dl_prio(p->normal_prio) ||
(pi_task && dl_entity_preempt(&pi_task->dl, &p->dl))) {
p->dl.dl_boosted = 1;
- enqueue_flag = ENQUEUE_REPLENISH;
+ enqueue_flag |= ENQUEUE_REPLENISH;
} else
p->dl.dl_boosted = 0;
p->sched_class = &dl_sched_class;
@@ -3371,7 +3398,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
if (dl_prio(oldprio))
p->dl.dl_boosted = 0;
if (oldprio < prio)
- enqueue_flag = ENQUEUE_HEAD;
+ enqueue_flag |= ENQUEUE_HEAD;
p->sched_class = &rt_sched_class;
} else {
if (dl_prio(oldprio))
@@ -3423,7 +3450,7 @@ void set_user_nice(struct task_struct *p, long nice)
}
queued = task_on_rq_queued(p);
if (queued)
- dequeue_task(rq, p, 0);
+ dequeue_task(rq, p, DEQUEUE_SAVE);
p->static_prio = NICE_TO_PRIO(nice);
set_load_weight(p);
@@ -3432,7 +3459,7 @@ void set_user_nice(struct task_struct *p, long nice)
delta = p->prio - old_prio;
if (queued) {
- enqueue_task(rq, p, 0);
+ enqueue_task(rq, p, ENQUEUE_RESTORE);
/*
* If the task increased its priority or is running and
* lowered its priority, then reschedule its CPU:
@@ -3753,10 +3780,7 @@ recheck:
} else {
reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK);
- if (policy != SCHED_DEADLINE &&
- policy != SCHED_FIFO && policy != SCHED_RR &&
- policy != SCHED_NORMAL && policy != SCHED_BATCH &&
- policy != SCHED_IDLE)
+ if (!valid_policy(policy))
return -EINVAL;
}
@@ -3812,7 +3836,7 @@ recheck:
* Treat SCHED_IDLE as nice 20. Only allow a switch to
* SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
*/
- if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) {
+ if (idle_policy(p->policy) && !idle_policy(policy)) {
if (!can_nice(p, task_nice(p)))
return -EPERM;
}
@@ -3937,7 +3961,7 @@ change:
queued = task_on_rq_queued(p);
running = task_current(rq, p);
if (queued)
- dequeue_task(rq, p, 0);
+ dequeue_task(rq, p, DEQUEUE_SAVE);
if (running)
put_prev_task(rq, p);
@@ -3947,11 +3971,15 @@ change:
if (running)
p->sched_class->set_curr_task(rq);
if (queued) {
+ int enqueue_flags = ENQUEUE_RESTORE;
/*
* We enqueue to tail when the priority of a task is
* increased (user space view).
*/
- enqueue_task(rq, p, oldprio <= p->prio ? ENQUEUE_HEAD : 0);
+ if (oldprio <= p->prio)
+ enqueue_flags |= ENQUEUE_HEAD;
+
+ enqueue_task(rq, p, enqueue_flags);
}
check_class_changed(rq, p, prev_class, oldprio);
@@ -5101,7 +5129,7 @@ void sched_setnuma(struct task_struct *p, int nid)
running = task_current(rq, p);
if (queued)
- dequeue_task(rq, p, 0);
+ dequeue_task(rq, p, DEQUEUE_SAVE);
if (running)
put_prev_task(rq, p);
@@ -5110,7 +5138,7 @@ void sched_setnuma(struct task_struct *p, int nid)
if (running)
p->sched_class->set_curr_task(rq);
if (queued)
- enqueue_task(rq, p, 0);
+ enqueue_task(rq, p, ENQUEUE_RESTORE);
task_rq_unlock(rq, p, &flags);
}
#endif /* CONFIG_NUMA_BALANCING */
@@ -5531,21 +5559,27 @@ static void set_cpu_rq_start_time(void)
static int sched_cpu_active(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
+ int cpu = (long)hcpu;
+
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_STARTING:
set_cpu_rq_start_time();
return NOTIFY_OK;
+
case CPU_ONLINE:
/*
* At this point a starting CPU has marked itself as online via
* set_cpu_online(). But it might not yet have marked itself
* as active, which is essential from here on.
- *
- * Thus, fall-through and help the starting CPU along.
*/
+ set_cpu_active(cpu, true);
+ stop_machine_unpark(cpu);
+ return NOTIFY_OK;
+
case CPU_DOWN_FAILED:
- set_cpu_active((long)hcpu, true);
+ set_cpu_active(cpu, true);
return NOTIFY_OK;
+
default:
return NOTIFY_DONE;
}
@@ -6477,7 +6511,8 @@ static struct sched_domain_topology_level default_topology[] = {
{ NULL, },
};
-struct sched_domain_topology_level *sched_domain_topology = default_topology;
+static struct sched_domain_topology_level *sched_domain_topology =
+ default_topology;
#define for_each_sd_topology(tl) \
for (tl = sched_domain_topology; tl->mask; tl++)
@@ -7478,7 +7513,7 @@ void __init sched_init(void)
#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
static inline int preempt_count_equals(int preempt_offset)
{
- int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
+ int nested = preempt_count() + rcu_preempt_depth();
return (nested == preempt_offset);
}
@@ -7725,7 +7760,7 @@ void sched_move_task(struct task_struct *tsk)
queued = task_on_rq_queued(tsk);
if (queued)
- dequeue_task(rq, tsk, 0);
+ dequeue_task(rq, tsk, DEQUEUE_SAVE);
if (unlikely(running))
put_prev_task(rq, tsk);
@@ -7741,7 +7776,7 @@ void sched_move_task(struct task_struct *tsk)
#ifdef CONFIG_FAIR_GROUP_SCHED
if (tsk->sched_class->task_move_group)
- tsk->sched_class->task_move_group(tsk, queued);
+ tsk->sched_class->task_move_group(tsk);
else
#endif
set_task_rq(tsk, task_cpu(tsk));
@@ -7749,7 +7784,7 @@ void sched_move_task(struct task_struct *tsk)
if (unlikely(running))
tsk->sched_class->set_curr_task(rq);
if (queued)
- enqueue_task(rq, tsk, 0);
+ enqueue_task(rq, tsk, ENQUEUE_RESTORE);
task_rq_unlock(rq, tsk, &flags);
}
@@ -8213,14 +8248,6 @@ static void cpu_cgroup_exit(struct cgroup_subsys_state *css,
struct cgroup_subsys_state *old_css,
struct task_struct *task)
{
- /*
- * cgroup_exit() is called in the copy_process() failure path.
- * Ignore this case since the task hasn't ran yet, this avoids
- * trying to poke a half freed task state from generic code.
- */
- if (!(task->flags & PF_EXITING))
- return;
-
sched_move_task(task);
}