sched/core: Add rq->lock wrappers
The missing update_rq_clock() check can work with partial rq->lock
wrappery, since a missing wrapper can cause the warning to not be
emitted when it should have, but cannot cause the warning to trigger
when it should not have.
The duplicate update_rq_clock() check however can cause false warnings
to trigger. Therefore add more comprehensive rq->lock wrappery.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 1bd15d0..c5a514b 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -86,21 +86,6 @@ int sysctl_sched_rt_runtime = 950000;
cpumask_var_t cpu_isolated_map;
/*
- * this_rq_lock - lock this runqueue and disable interrupts.
- */
-static struct rq *this_rq_lock(void)
- __acquires(rq->lock)
-{
- struct rq *rq;
-
- local_irq_disable();
- rq = this_rq();
- raw_spin_lock(&rq->lock);
-
- return rq;
-}
-
-/*
* __task_rq_lock - lock the rq @p resides on.
*/
struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
@@ -264,13 +249,14 @@ static void hrtick_clear(struct rq *rq)
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());
- raw_spin_lock(&rq->lock);
+ rq_lock(rq, &rf);
update_rq_clock(rq);
rq->curr->sched_class->task_tick(rq, rq->curr, 1);
- raw_spin_unlock(&rq->lock);
+ rq_unlock(rq, &rf);
return HRTIMER_NORESTART;
}
@@ -290,11 +276,12 @@ static void __hrtick_restart(struct rq *rq)
static void __hrtick_start(void *arg)
{
struct rq *rq = arg;
+ struct rq_flags rf;
- raw_spin_lock(&rq->lock);
+ rq_lock(rq, &rf);
__hrtick_restart(rq);
rq->hrtick_csd_pending = 0;
- raw_spin_unlock(&rq->lock);
+ rq_unlock(rq, &rf);
}
/*
@@ -949,18 +936,19 @@ void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
*
* Returns (locked) new rq. Old rq's lock is released.
*/
-static struct rq *move_queued_task(struct rq *rq, struct task_struct *p, int new_cpu)
+static struct rq *move_queued_task(struct rq *rq, struct rq_flags *rf,
+ struct task_struct *p, int new_cpu)
{
lockdep_assert_held(&rq->lock);
p->on_rq = TASK_ON_RQ_MIGRATING;
dequeue_task(rq, p, 0);
set_task_cpu(p, new_cpu);
- raw_spin_unlock(&rq->lock);
+ rq_unlock(rq, rf);
rq = cpu_rq(new_cpu);
- raw_spin_lock(&rq->lock);
+ rq_lock(rq, rf);
BUG_ON(task_cpu(p) != new_cpu);
enqueue_task(rq, p, 0);
p->on_rq = TASK_ON_RQ_QUEUED;
@@ -983,7 +971,8 @@ struct migration_arg {
* 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 task_struct *p, int dest_cpu)
+static struct rq *__migrate_task(struct rq *rq, struct rq_flags *rf,
+ struct task_struct *p, int dest_cpu)
{
if (unlikely(!cpu_active(dest_cpu)))
return rq;
@@ -992,7 +981,7 @@ static struct rq *__migrate_task(struct rq *rq, struct task_struct *p, int dest_
if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
return rq;
- rq = move_queued_task(rq, p, dest_cpu);
+ rq = move_queued_task(rq, rf, p, dest_cpu);
return rq;
}
@@ -1007,6 +996,7 @@ 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
@@ -1021,7 +1011,7 @@ static int migration_cpu_stop(void *data)
sched_ttwu_pending();
raw_spin_lock(&p->pi_lock);
- raw_spin_lock(&rq->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
@@ -1029,11 +1019,11 @@ static int migration_cpu_stop(void *data)
*/
if (task_rq(p) == rq) {
if (task_on_rq_queued(p))
- rq = __migrate_task(rq, p, arg->dest_cpu);
+ rq = __migrate_task(rq, &rf, p, arg->dest_cpu);
else
p->wake_cpu = arg->dest_cpu;
}
- raw_spin_unlock(&rq->lock);
+ rq_unlock(rq, &rf);
raw_spin_unlock(&p->pi_lock);
local_irq_enable();
@@ -1153,9 +1143,7 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
* OK, since we're going to drop the lock immediately
* afterwards anyway.
*/
- rq_unpin_lock(rq, &rf);
- rq = move_queued_task(rq, p, dest_cpu);
- rq_repin_lock(rq, &rf);
+ rq = move_queued_task(rq, &rf, p, dest_cpu);
}
out:
task_rq_unlock(rq, p, &rf);
@@ -1220,16 +1208,24 @@ 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);
+
p->on_rq = TASK_ON_RQ_MIGRATING;
deactivate_task(src_rq, p, 0);
set_task_cpu(p, cpu);
activate_task(dst_rq, p, 0);
p->on_rq = TASK_ON_RQ_QUEUED;
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
@@ -1729,14 +1725,12 @@ void sched_ttwu_pending(void)
struct rq *rq = this_rq();
struct llist_node *llist = llist_del_all(&rq->wake_list);
struct task_struct *p;
- unsigned long flags;
struct rq_flags rf;
if (!llist)
return;
- raw_spin_lock_irqsave(&rq->lock, flags);
- rq_pin_lock(rq, &rf);
+ rq_lock_irqsave(rq, &rf);
while (llist) {
int wake_flags = 0;
@@ -1750,8 +1744,7 @@ void sched_ttwu_pending(void)
ttwu_do_activate(rq, p, wake_flags, &rf);
}
- rq_unpin_lock(rq, &rf);
- raw_spin_unlock_irqrestore(&rq->lock, flags);
+ rq_unlock_irqrestore(rq, &rf);
}
void scheduler_ipi(void)
@@ -1809,7 +1802,7 @@ static void ttwu_queue_remote(struct task_struct *p, int cpu, int wake_flags)
void wake_up_if_idle(int cpu)
{
struct rq *rq = cpu_rq(cpu);
- unsigned long flags;
+ struct rq_flags rf;
rcu_read_lock();
@@ -1819,11 +1812,11 @@ void wake_up_if_idle(int cpu)
if (set_nr_if_polling(rq->idle)) {
trace_sched_wake_idle_without_ipi(cpu);
} else {
- raw_spin_lock_irqsave(&rq->lock, flags);
+ rq_lock_irqsave(rq, &rf);
if (is_idle_task(rq->curr))
smp_send_reschedule(cpu);
/* Else CPU is not idle, do nothing here: */
- raw_spin_unlock_irqrestore(&rq->lock, flags);
+ rq_unlock_irqrestore(rq, &rf);
}
out:
@@ -1849,11 +1842,9 @@ static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags)
}
#endif
- raw_spin_lock(&rq->lock);
- rq_pin_lock(rq, &rf);
+ rq_lock(rq, &rf);
ttwu_do_activate(rq, p, wake_flags, &rf);
- rq_unpin_lock(rq, &rf);
- raw_spin_unlock(&rq->lock);
+ rq_unlock(rq, &rf);
}
/*
@@ -2100,11 +2091,9 @@ static void try_to_wake_up_local(struct task_struct *p, struct rq_flags *rf)
* disabled avoiding further scheduler activity on it and we've
* not yet picked a replacement task.
*/
- rq_unpin_lock(rq, rf);
- raw_spin_unlock(&rq->lock);
+ rq_unlock(rq, rf);
raw_spin_lock(&p->pi_lock);
- raw_spin_lock(&rq->lock);
- rq_repin_lock(rq, rf);
+ rq_relock(rq, rf);
}
if (!(p->state & TASK_NORMAL))
@@ -2778,9 +2767,9 @@ static void __balance_callback(struct rq *rq)
{
struct callback_head *head, *next;
void (*func)(struct rq *rq);
- unsigned long flags;
+ struct rq_flags rf;
- raw_spin_lock_irqsave(&rq->lock, flags);
+ rq_lock_irqsave(rq, &rf);
head = rq->balance_callback;
rq->balance_callback = NULL;
while (head) {
@@ -2791,7 +2780,7 @@ static void __balance_callback(struct rq *rq)
func(rq);
}
- raw_spin_unlock_irqrestore(&rq->lock, flags);
+ rq_unlock_irqrestore(rq, &rf);
}
static inline void balance_callback(struct rq *rq)
@@ -3096,15 +3085,18 @@ 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;
sched_clock_tick();
- raw_spin_lock(&rq->lock);
+ rq_lock(rq, &rf);
+
update_rq_clock(rq);
curr->sched_class->task_tick(rq, curr, 0);
cpu_load_update_active(rq);
calc_global_load_tick(rq);
- raw_spin_unlock(&rq->lock);
+
+ rq_unlock(rq, &rf);
perf_event_task_tick();
@@ -3389,8 +3381,7 @@ static void __sched notrace __schedule(bool preempt)
* done by the caller to avoid the race with signal_wake_up().
*/
smp_mb__before_spinlock();
- raw_spin_lock(&rq->lock);
- rq_pin_lock(rq, &rf);
+ rq_lock(rq, &rf);
/* Promote REQ to ACT */
rq->clock_update_flags <<= 1;
@@ -3442,8 +3433,7 @@ static void __sched notrace __schedule(bool preempt)
rq = context_switch(rq, prev, next, &rf);
} else {
rq->clock_update_flags &= ~(RQCF_ACT_SKIP|RQCF_REQ_SKIP);
- rq_unpin_lock(rq, &rf);
- raw_spin_unlock_irq(&rq->lock);
+ rq_unlock_irq(rq, &rf);
}
balance_callback(rq);
@@ -4926,7 +4916,12 @@ SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
*/
SYSCALL_DEFINE0(sched_yield)
{
- struct rq *rq = this_rq_lock();
+ struct rq_flags rf;
+ struct rq *rq;
+
+ local_irq_disable();
+ rq = this_rq();
+ rq_lock(rq, &rf);
schedstat_inc(rq->yld_count);
current->sched_class->yield_task(rq);
@@ -4935,9 +4930,8 @@ SYSCALL_DEFINE0(sched_yield)
* Since we are going to call schedule() anyway, there's
* no need to preempt or enable interrupts:
*/
- __release(rq->lock);
- spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
- do_raw_spin_unlock(&rq->lock);
+ preempt_disable();
+ rq_unlock(rq, &rf);
sched_preempt_enable_no_resched();
schedule();
@@ -5582,11 +5576,11 @@ static struct task_struct fake_task = {
* there's no concurrency possible, we hold the required locks anyway
* because of lock validation efforts.
*/
-static void migrate_tasks(struct rq *dead_rq)
+static void migrate_tasks(struct rq *dead_rq, struct rq_flags *rf)
{
struct rq *rq = dead_rq;
struct task_struct *next, *stop = rq->stop;
- struct rq_flags rf;
+ struct rq_flags orf = *rf;
int dest_cpu;
/*
@@ -5605,9 +5599,7 @@ static void migrate_tasks(struct rq *dead_rq)
* class method both need to have an up-to-date
* value of rq->clock[_task]
*/
- rq_pin_lock(rq, &rf);
update_rq_clock(rq);
- rq_unpin_lock(rq, &rf);
for (;;) {
/*
@@ -5620,8 +5612,7 @@ static void migrate_tasks(struct rq *dead_rq)
/*
* pick_next_task() assumes pinned rq->lock:
*/
- rq_repin_lock(rq, &rf);
- next = pick_next_task(rq, &fake_task, &rf);
+ next = pick_next_task(rq, &fake_task, rf);
BUG_ON(!next);
next->sched_class->put_prev_task(rq, next);
@@ -5634,10 +5625,9 @@ static void migrate_tasks(struct rq *dead_rq)
* because !cpu_active at this point, which means load-balance
* will not interfere. Also, stop-machine.
*/
- rq_unpin_lock(rq, &rf);
- raw_spin_unlock(&rq->lock);
+ rq_unlock(rq, rf);
raw_spin_lock(&next->pi_lock);
- raw_spin_lock(&rq->lock);
+ rq_relock(rq, rf);
/*
* Since we're inside stop-machine, _nothing_ should have
@@ -5651,12 +5641,12 @@ static void migrate_tasks(struct rq *dead_rq)
/* Find suitable destination for @next, with force if needed. */
dest_cpu = select_fallback_rq(dead_rq->cpu, next);
-
- rq = __migrate_task(rq, next, dest_cpu);
+ rq = __migrate_task(rq, rf, next, dest_cpu);
if (rq != dead_rq) {
- raw_spin_unlock(&rq->lock);
+ rq_unlock(rq, rf);
rq = dead_rq;
- raw_spin_lock(&rq->lock);
+ *rf = orf;
+ rq_relock(rq, rf);
}
raw_spin_unlock(&next->pi_lock);
}
@@ -5769,7 +5759,7 @@ static int cpuset_cpu_inactive(unsigned int cpu)
int sched_cpu_activate(unsigned int cpu)
{
struct rq *rq = cpu_rq(cpu);
- unsigned long flags;
+ struct rq_flags rf;
set_cpu_active(cpu, true);
@@ -5787,12 +5777,12 @@ int sched_cpu_activate(unsigned int cpu)
* 2) At runtime, if cpuset_cpu_active() fails to rebuild the
* domains.
*/
- raw_spin_lock_irqsave(&rq->lock, flags);
+ rq_lock_irqsave(rq, &rf);
if (rq->rd) {
BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
set_rq_online(rq);
}
- raw_spin_unlock_irqrestore(&rq->lock, flags);
+ rq_unlock_irqrestore(rq, &rf);
update_max_interval();
@@ -5850,18 +5840,20 @@ int sched_cpu_starting(unsigned int cpu)
int sched_cpu_dying(unsigned int cpu)
{
struct rq *rq = cpu_rq(cpu);
- unsigned long flags;
+ struct rq_flags rf;
/* Handle pending wakeups and then migrate everything off */
sched_ttwu_pending();
- raw_spin_lock_irqsave(&rq->lock, flags);
+
+ rq_lock_irqsave(rq, &rf);
if (rq->rd) {
BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
set_rq_offline(rq);
}
- migrate_tasks(rq);
+ migrate_tasks(rq, &rf);
BUG_ON(rq->nr_running != 1);
- raw_spin_unlock_irqrestore(&rq->lock, flags);
+ rq_unlock_irqrestore(rq, &rf);
+
calc_load_migrate(rq);
update_max_interval();
nohz_balance_exit_idle(cpu);
@@ -7011,14 +7003,15 @@ static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota)
for_each_online_cpu(i) {
struct cfs_rq *cfs_rq = tg->cfs_rq[i];
struct rq *rq = cfs_rq->rq;
+ struct rq_flags rf;
- raw_spin_lock_irq(&rq->lock);
+ 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);
- raw_spin_unlock_irq(&rq->lock);
+ rq_unlock_irq(rq, &rf);
}
if (runtime_was_enabled && !runtime_enabled)
cfs_bandwidth_usage_dec();
