Commit cf3e9443 authored by Tejun Heo's avatar Tejun Heo
Browse files

sched_ext: Replace consume_local_task() with move_local_task_to_local_dsq() 



- Rename move_task_to_local_dsq() to move_remote_task_to_local_dsq().

- Rename consume_local_task() to move_local_task_to_local_dsq() and remove
  task_unlink_from_dsq() and source DSQ unlocking from it.

This is to make the migration code easier to reuse.

No functional changes intended.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarDavid Vernet <void@manifault.com>
parent d434210e

kernel/sched/ext.c

+26 −16
Original line number Diff line number Diff line
@@ -2172,23 +2172,30 @@ static bool yield_to_task_scx(struct rq *rq, struct task_struct *to) 
		return false;

}



static void consume_local_task(struct task_struct *p,

			       struct scx_dispatch_q *dsq, struct rq *rq)

static void move_local_task_to_local_dsq(struct task_struct *p, u64 enq_flags,

					 struct scx_dispatch_q *src_dsq,

					 struct rq *dst_rq)

{

	lockdep_assert_held(&dsq->lock);	/* released on return */

	struct scx_dispatch_q *dst_dsq = &dst_rq->scx.local_dsq;



	/* @dsq is locked and @p is on @dst_rq */

	lockdep_assert_held(&src_dsq->lock);

	lockdep_assert_rq_held(dst_rq);



	/* @dsq is locked and @p is on this rq */

	WARN_ON_ONCE(p->scx.holding_cpu >= 0);

	task_unlink_from_dsq(p, dsq);

	list_add_tail(&p->scx.dsq_list.node, &rq->scx.local_dsq.list);

	dsq_mod_nr(&rq->scx.local_dsq, 1);

	p->scx.dsq = &rq->scx.local_dsq;

	raw_spin_unlock(&dsq->lock);



	if (enq_flags & (SCX_ENQ_HEAD | SCX_ENQ_PREEMPT))

		list_add(&p->scx.dsq_list.node, &dst_dsq->list);

	else

		list_add_tail(&p->scx.dsq_list.node, &dst_dsq->list);



	dsq_mod_nr(dst_dsq, 1);

	p->scx.dsq = dst_dsq;

}



#ifdef CONFIG_SMP

/**

 * move_task_to_local_dsq - Move a task from a different rq to a local DSQ

 * move_remote_task_to_local_dsq - Move a task from a foreign rq to a local DSQ

 * @p: task to move

 * @enq_flags: %SCX_ENQ_*

 * @src_rq: rq to move the task from, locked on entry, released on return
@@ -2196,7 +2203,7 @@ static void consume_local_task(struct task_struct *p, 
 *

 * Move @p which is currently on @src_rq to @dst_rq's local DSQ.

 */

static void move_task_to_local_dsq(struct task_struct *p, u64 enq_flags,

static void move_remote_task_to_local_dsq(struct task_struct *p, u64 enq_flags,

					  struct rq *src_rq, struct rq *dst_rq)

{

	lockdep_assert_rq_held(src_rq);
@@ -2320,7 +2327,7 @@ static bool consume_remote_task(struct rq *this_rq, struct task_struct *p, 
	raw_spin_rq_unlock(this_rq);



	if (unlink_dsq_and_lock_src_rq(p, dsq, src_rq)) {

		move_task_to_local_dsq(p, 0, src_rq, this_rq);

		move_remote_task_to_local_dsq(p, 0, src_rq, this_rq);

		return true;

	} else {

		raw_spin_rq_unlock(src_rq);
@@ -2351,7 +2358,9 @@ static bool consume_dispatch_q(struct rq *rq, struct scx_dispatch_q *dsq) 
		struct rq *task_rq = task_rq(p);



		if (rq == task_rq) {

			consume_local_task(p, dsq, rq);

			task_unlink_from_dsq(p, dsq);

			move_local_task_to_local_dsq(p, 0, dsq, rq);

			raw_spin_unlock(&dsq->lock);

			return true;

		}
@@ -2431,13 +2440,14 @@ static void dispatch_to_local_dsq(struct rq *rq, struct scx_dispatch_q *dst_dsq, 
		/*

		 * If @p is staying on the same rq, there's no need to go

		 * through the full deactivate/activate cycle. Optimize by

		 * abbreviating the operations in move_task_to_local_dsq().

		 * abbreviating move_remote_task_to_local_dsq().

		 */

		if (src_rq == dst_rq) {

			p->scx.holding_cpu = -1;

			dispatch_enqueue(&dst_rq->scx.local_dsq, p, enq_flags);

		} else {

			move_task_to_local_dsq(p, enq_flags, src_rq, dst_rq);

			move_remote_task_to_local_dsq(p, enq_flags,

						      src_rq, dst_rq);

		}



		/* if the destination CPU is idle, wake it up */