[PATCH V1] sched: Cancel the slice protection of the idle entity

[zihan zhou]

A wakeup non-idle entity should preempt idle entity at any time,
but because of the slice protection of the idle entity, the non-idle
entity has to wait, so just cancel it.

Signed-off-by: zihan zhou <15645113830zzh@xxxxxxxxx>
---
 kernel/sched/fair.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 3e9ca38512de..7777d110d053 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8851,8 +8851,19 @@ static void check_preempt_wakeup_fair(struct rq *rq, struct task_struct *p, int
 	 * Preempt an idle entity in favor of a non-idle entity (and don't preempt
 	 * in the inverse case).
 	 */
-	if (cse_is_idle && !pse_is_idle)
+	if (cse_is_idle && !pse_is_idle) {
+
+		/*
+		 * When non-idle entity preempt an idle entity,
+		 * don't give idle entity slice protection.
+		 */
+		if (se->vlag == se->deadline)
+			se->vlag = se->deadline + 1;
+
 		goto preempt;
+
+	}
+
 	if (cse_is_idle != pse_is_idle)
 		return;
 
-- 
2.33.0