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Merge branch 'sched/urgent'

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This commit is contained in:
Peter Zijlstra
2020-07-22 10:22:02 +02:00
parent 9d246053a6 d136122f58
commit 015dc08918
654 changed files with 5148 additions and 2792 deletions
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24
kernel/sched/core.c
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@@ -4193,9 +4193,6 @@ static void __sched notrace __schedule(bool preempt)
local_irq_disable();
rcu_note_context_switch(preempt);
/* See deactivate_task() below. */
prev_state = prev->state;
/*
* Make sure that signal_pending_state()->signal_pending() below
* can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
@@ -4219,11 +4216,16 @@ static void __sched notrace __schedule(bool preempt)
update_rq_clock(rq);
switch_count = &prev->nivcsw;
/*
* We must re-load prev->state in case ttwu_remote() changed it
* before we acquired rq->lock.
* 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.
*/
if (!preempt && prev_state && prev_state == prev->state) {
prev_state = prev->state;
if (!preempt && prev_state) {
if (signal_pending_state(prev_state, prev)) {
prev->state = TASK_RUNNING;
} else {
@@ -4237,10 +4239,12 @@ static void __sched notrace __schedule(bool preempt)
/*
* __schedule() ttwu()
* prev_state = prev->state; if (READ_ONCE(p->on_rq) && ...)
* LOCK rq->lock goto out;
* smp_mb__after_spinlock(); smp_acquire__after_ctrl_dep();
* p->on_rq = 0; p->state = TASK_WAKING;
* 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.
*/