Commit 160fb0d8 authored by Chengming Zhou's avatar Chengming Zhou Committed by Ingo Molnar
Browse files

sched/core: Reorganize ttwu_do_wakeup() and ttwu_do_activate() 



ttwu_do_activate() is used for a complete wakeup, in which we will
activate_task() and use ttwu_do_wakeup() to mark the task runnable
and perform wakeup-preemption, also call class->task_woken() callback
and update the rq->idle_stamp.

Since ttwu_runnable() is not a complete wakeup, don't need all those
done in ttwu_do_wakeup(), so we can move those to ttwu_do_activate()
to simplify ttwu_do_wakeup(), making it only mark the task runnable
to be reused in ttwu_runnable() and try_to_wake_up().

This patch should not have any functional changes.

Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarChengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20221223103257.4962-2-zhouchengming@bytedance.com
parent efe09385

kernel/sched/core.c

+31 −33
Original line number Diff line number Diff line
@@ -3625,14 +3625,39 @@ ttwu_stat(struct task_struct *p, int cpu, int wake_flags) 
}



/*

 * Mark the task runnable and perform wakeup-preemption.

 * Mark the task runnable.

 */

static void ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags,

			   struct rq_flags *rf)

static inline void ttwu_do_wakeup(struct task_struct *p)

{

	check_preempt_curr(rq, p, wake_flags);

	WRITE_ONCE(p->__state, TASK_RUNNING);

	trace_sched_wakeup(p);

}



static void

ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags,

		 struct rq_flags *rf)

{

	int en_flags = ENQUEUE_WAKEUP | ENQUEUE_NOCLOCK;



	lockdep_assert_rq_held(rq);



	if (p->sched_contributes_to_load)

		rq->nr_uninterruptible--;



#ifdef CONFIG_SMP

	if (wake_flags & WF_MIGRATED)

		en_flags |= ENQUEUE_MIGRATED;

	else

#endif

	if (p->in_iowait) {

		delayacct_blkio_end(p);

		atomic_dec(&task_rq(p)->nr_iowait);

	}



	activate_task(rq, p, en_flags);

	check_preempt_curr(rq, p, wake_flags);



	ttwu_do_wakeup(p);



#ifdef CONFIG_SMP

	if (p->sched_class->task_woken) {
@@ -3662,31 +3687,6 @@ static void ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags, 
#endif

}



static void

ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags,

		 struct rq_flags *rf)

{

	int en_flags = ENQUEUE_WAKEUP | ENQUEUE_NOCLOCK;



	lockdep_assert_rq_held(rq);



	if (p->sched_contributes_to_load)

		rq->nr_uninterruptible--;



#ifdef CONFIG_SMP

	if (wake_flags & WF_MIGRATED)

		en_flags |= ENQUEUE_MIGRATED;

	else

#endif

	if (p->in_iowait) {

		delayacct_blkio_end(p);

		atomic_dec(&task_rq(p)->nr_iowait);

	}



	activate_task(rq, p, en_flags);

	ttwu_do_wakeup(rq, p, wake_flags, rf);

}



/*

 * Consider @p being inside a wait loop:

 *
@@ -3728,8 +3728,7 @@ static int ttwu_runnable(struct task_struct *p, int wake_flags) 
			update_rq_clock(rq);

			check_preempt_curr(rq, p, wake_flags);

		}

		WRITE_ONCE(p->__state, TASK_RUNNING);

		trace_sched_wakeup(p);

		ttwu_do_wakeup(p);

		ret = 1;

	}

	__task_rq_unlock(rq, &rf);
@@ -4095,8 +4094,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) 
			goto out;



		trace_sched_waking(p);

		WRITE_ONCE(p->__state, TASK_RUNNING);

		trace_sched_wakeup(p);

		ttwu_do_wakeup(p);

		goto out;

	}