Commit fe3ad7a5 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'sched_urgent_for_v6.17_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull scheduler fixes from Borislav Petkov:

 - Fix a stall on the CPU offline path due to mis-counting a deadline
   server task twice as part of the runqueue's running tasks count

 - Fix a realtime tasks starvation case where failure to enqueue a timer
   whose expiration time is already in the past would cause repeated
   attempts to re-enqueue a deadline server task which leads to starving
   the former, realtime one

 - Prevent a delayed deadline server task stop from breaking the
   per-runqueue bandwidth tracking

 - Have a function checking whether the deadline server task has
   stopped, return the correct value

* tag 'sched_urgent_for_v6.17_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/deadline: Don't count nr_running for dl_server proxy tasks
  sched/deadline: Fix RT task potential starvation when expiry time passed
  sched/deadline: Always stop dl-server before changing parameters
  sched/deadline: Fix dl_server_stopped()
parents c9e4e961 52d15521

kernel/sched/deadline.c

+12 −6
Original line number Diff line number Diff line
@@ -1496,11 +1496,13 @@ static void update_curr_dl_se(struct rq *rq, struct sched_dl_entity *dl_se, s64 
		}



		if (unlikely(is_dl_boosted(dl_se) || !start_dl_timer(dl_se))) {

			if (dl_server(dl_se))

				enqueue_dl_entity(dl_se, ENQUEUE_REPLENISH);

			else

			if (dl_server(dl_se)) {

				replenish_dl_new_period(dl_se, rq);

				start_dl_timer(dl_se);

			} else {

				enqueue_task_dl(rq, dl_task_of(dl_se), ENQUEUE_REPLENISH);

			}

		}



		if (!is_leftmost(dl_se, &rq->dl))

			resched_curr(rq);
@@ -1611,7 +1613,7 @@ void dl_server_stop(struct sched_dl_entity *dl_se) 
static bool dl_server_stopped(struct sched_dl_entity *dl_se)

{

	if (!dl_se->dl_server_active)

		return false;

		return true;



	if (dl_se->dl_server_idle) {

		dl_server_stop(dl_se);
@@ -1849,6 +1851,8 @@ void inc_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) 
	u64 deadline = dl_se->deadline;



	dl_rq->dl_nr_running++;



	if (!dl_server(dl_se))

		add_nr_running(rq_of_dl_rq(dl_rq), 1);



	inc_dl_deadline(dl_rq, deadline);
@@ -1859,6 +1863,8 @@ void dec_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) 
{

	WARN_ON(!dl_rq->dl_nr_running);

	dl_rq->dl_nr_running--;



	if (!dl_server(dl_se))

		sub_nr_running(rq_of_dl_rq(dl_rq), 1);



	dec_dl_deadline(dl_rq, dl_se->deadline);

kernel/sched/debug.c

+2 −4
Original line number Diff line number Diff line
@@ -376,10 +376,8 @@ static ssize_t sched_fair_server_write(struct file *filp, const char __user *ubu 
			return  -EINVAL;

		}



		if (rq->cfs.h_nr_queued) {

		update_rq_clock(rq);

		dl_server_stop(&rq->fair_server);

		}



		retval = dl_server_apply_params(&rq->fair_server, runtime, period, 0);

		if (retval)