[PATCH 5/6 v3] sched/eevdf: Always update slice protection

[Vincent Guittot]

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>
Tested-by: K Prateek Nayak <kprateek.nayak@xxxxxxx>
---
 kernel/sched/fair.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 719aa53851e4..f972987618e7 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -9824,17 +9824,18 @@ static void wakeup_preempt_fair(struct rq *rq, struct task_struct *p, int wake_f
 	if (cse_is_idle && !pse_is_idle)
 		goto preempt;
 
+	cfs_rq = cfs_rq_of(se);
+	update_curr(cfs_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;
 
-	cfs_rq = cfs_rq_of(se);
-	update_curr(cfs_rq);
 	/*
 	 * If @p has a shorter slice than current and @p is eligible, override
 	 * current's slice protection in order to allow preemption.
@@ -9851,7 +9852,7 @@ 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) &&
@@ -9897,7 +9898,7 @@ static void wakeup_preempt_fair(struct rq *rq, struct task_struct *p, int wake_f
 	 */
 	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);
 
-- 
2.43.0