Merge tag 'sched-urgent-2020-07-25' of... (3077805e) · Commits · 戴 / test

kernel/sched/core.c

+15 −10

Original line number	Diff line number	Diff line
		@@ -4119,9 +4119,6 @@ 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)
		@@ -4145,11 +4142,16 @@ 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 {
		@@ -4163,10 +4165,12 @@ 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.
		*/
		@@ -4481,6 +4485,7 @@ asmlinkage __visible void __sched preempt_schedule_irq(void)
		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);
		return try_to_wake_up(curr->private, mode, wake_flags);
		}
		EXPORT_SYMBOL(default_wake_function);

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