Commit 1ae5f5df authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

sched: Cleanup sched_delayed handling for class switches 



Use the new sched_class::switching_from() method to dequeue delayed
tasks before switching to another class.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarVincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: default avatarJuri Lelli <juri.lelli@redhat.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
parent 637b0682

kernel/sched/core.c

+8 −4
Original line number Diff line number Diff line
@@ -7366,9 +7366,6 @@ void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task) 
	if (prev_class != next_class)

		queue_flag |= DEQUEUE_CLASS;



	if (prev_class != next_class && p->se.sched_delayed)

		dequeue_task(rq, p, DEQUEUE_SLEEP | DEQUEUE_DELAYED | DEQUEUE_NOCLOCK);



	scoped_guard (sched_change, p, queue_flag) {

		/*

		 * Boosting condition are:
@@ -10840,9 +10837,16 @@ struct sched_change_ctx *sched_change_begin(struct task_struct *p, unsigned int 
	lockdep_assert_rq_held(rq);



	if (flags & DEQUEUE_CLASS) {

		if (p->sched_class->switching_from)

		if (p->sched_class->switching_from) {

			/*

			 * switching_from_fair() assumes CLASS implies NOCLOCK;

			 * fixing this assumption would mean switching_from()

			 * would need to be able to change flags.

			 */

			WARN_ON(!(flags & DEQUEUE_NOCLOCK));

			p->sched_class->switching_from(rq, p);

		}

	}



	*ctx = (struct sched_change_ctx){

		.p = p,

kernel/sched/ext.c

+0 −6
Original line number Diff line number Diff line
@@ -3922,9 +3922,6 @@ static void scx_disable_workfn(struct kthread_work *work) 
		if (old_class != new_class)

			queue_flags |= DEQUEUE_CLASS;



		if (old_class != new_class && p->se.sched_delayed)

			dequeue_task(task_rq(p), p, DEQUEUE_SLEEP | DEQUEUE_DELAYED | DEQUEUE_NOCLOCK);



		scoped_guard (sched_change, p, queue_flags) {

			p->sched_class = new_class;

		}
@@ -4673,9 +4670,6 @@ static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link) 
		if (old_class != new_class)

			queue_flags |= DEQUEUE_CLASS;



		if (old_class != new_class && p->se.sched_delayed)

			dequeue_task(task_rq(p), p, DEQUEUE_SLEEP | DEQUEUE_DELAYED | DEQUEUE_NOCLOCK);



		scoped_guard (sched_change, p, queue_flags) {

			p->scx.slice = SCX_SLICE_DFL;

			p->sched_class = new_class;

kernel/sched/fair.c

+7 −0
Original line number Diff line number Diff line
@@ -13249,6 +13249,12 @@ static void attach_task_cfs_rq(struct task_struct *p) 
	attach_entity_cfs_rq(se);

}



static void switching_from_fair(struct rq *rq, struct task_struct *p)

{

	if (p->se.sched_delayed)

		dequeue_task(rq, p, DEQUEUE_SLEEP | DEQUEUE_DELAYED | DEQUEUE_NOCLOCK);

}



static void switched_from_fair(struct rq *rq, struct task_struct *p)

{

	detach_task_cfs_rq(p);
@@ -13650,6 +13656,7 @@ DEFINE_SCHED_CLASS(fair) = { 


	.reweight_task		= reweight_task_fair,

	.prio_changed		= prio_changed_fair,

	.switching_from		= switching_from_fair,

	.switched_from		= switched_from_fair,

	.switched_to		= switched_to_fair,

kernel/sched/syscalls.c

+0 −3
Original line number Diff line number Diff line
@@ -687,9 +687,6 @@ int __sched_setscheduler(struct task_struct *p, 
	if (prev_class != next_class)

		queue_flags |= DEQUEUE_CLASS;



	if (prev_class != next_class && p->se.sched_delayed)

		dequeue_task(rq, p, DEQUEUE_SLEEP | DEQUEUE_DELAYED | DEQUEUE_NOCLOCK);



	scoped_guard (sched_change, p, queue_flags) {



		if (!(attr->sched_flags & SCHED_FLAG_KEEP_PARAMS)) {