[tip: sched/core] sched/eevdf: Always update slice protection

[tip-bot2 for Vincent Guittot]

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     7cd2ef17de5e11612001e98b6319f1793239b243
Gitweb:        https://git.kernel.org/tip/7cd2ef17de5e11612001e98b6319f1793239b243
Author:        Vincent Guittot <vincent.guittot@xxxxxxxxxx>
AuthorDate:    Wed, 24 Jun 2026 17:12:28 +02:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Tue, 30 Jun 2026 10:56:55 +02:00

sched/eevdf: Always update slice protection

Even if p will not preempt current, it modifies the avg_vruntime and
possibly the min slice. Make sure to update the slice protection with the
updated figures. As an example, Batch and Sched Idle tasks can otherwise
get a larger lag than their slice and finaly delay the scheduling of a
normal task, which deadline will be a later.

Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Tested-by: K Prateek Nayak <kprateek.nayak@xxxxxxx>
Link: https://patch.msgid.link/20260624151229.1710703-6-vincent.guittot@xxxxxxxxxx
---
 kernel/sched/fair.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 9046b2e..2547a97 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -9867,16 +9867,17 @@ static void wakeup_preempt_fair(struct rq *rq, struct task_struct *p, int wake_f
 	if (cse_is_idle && !pse_is_idle)
 		goto preempt;
 
+	update_curr_fair(rq);
+
 	if (cse_is_idle != pse_is_idle)
-		return;
+		goto update;
 
 	/*
 	 * BATCH and IDLE tasks do not preempt others.
 	 */
 	if (unlikely(!normal_policy(p->policy)))
-		return;
+		goto update;
 
-	update_curr_fair(rq);
 	/*
 	 * If @p has a shorter slice than current and @p is eligible, override
 	 * current's slice protection in order to allow preemption.
@@ -9893,7 +9894,7 @@ static void wakeup_preempt_fair(struct rq *rq, struct task_struct *p, int wake_f
 	 * EEVDF to forcibly queue an ineligible task.
 	 */
 	if ((wake_flags & WF_FORK) || pse->sched_delayed)
-		return;
+		goto update;
 
 	/* Prefer picking wakee soon if appropriate. */
 	if (sched_feat(NEXT_BUDDY) && set_preempt_buddy(cfs_rq, pse)) {
@@ -9934,7 +9935,7 @@ pick:
 	 */
 	if (preempt_action == PREEMPT_WAKEUP_SHORT && entity_eligible(cfs_rq, pse))
 		goto preempt;
-
+update:
 	if (sched_feat(RUN_TO_PARITY))
 		update_protect_slice(cfs_rq, se);