When a delay-dequeue task is woken and requeued back, it may
becomes eligible, and changes the CPU idle status,
so we need to update the rq->avg_idle for it.

This patch adds a new parameter for requeue_delayed_entity(),
and updates the rq->avg_idle as needed.

Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com>
---
 kernel/sched/fair.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c1a8fa043156..2ac630ecdbd5 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5208,7 +5208,7 @@ static void check_enqueue_throttle(struct cfs_rq *cfs_rq);
 static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq);
 
 static void
-requeue_delayed_entity(struct sched_entity *se);
+requeue_delayed_entity(struct rq *rq, struct sched_entity *se);
 
 static void
 enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
@@ -6835,7 +6835,7 @@ static int sched_idle_cpu(int cpu)
 }
 
 static void
-requeue_delayed_entity(struct sched_entity *se)
+requeue_delayed_entity(struct rq *rq, struct sched_entity *se)
 {
 	struct cfs_rq *cfs_rq = cfs_rq_of(se);
 
@@ -6862,6 +6862,10 @@ requeue_delayed_entity(struct sched_entity *se)
 	}
 
 	update_load_avg(cfs_rq, se, 0);
+
+	if (entity_eligible(cfs_rq, se))
+		update_rq_avg_idle(rq);
+
 	clear_delayed(se);
 }
 
@@ -6894,7 +6898,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
 		util_est_enqueue(&rq->cfs, p);
 
 	if (flags & ENQUEUE_DELAYED) {
-		requeue_delayed_entity(se);
+		requeue_delayed_entity(rq, se);
 		return;
 	}
 
@@ -6912,7 +6916,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
 	for_each_sched_entity(se) {
 		if (se->on_rq) {
 			if (se->sched_delayed)
-				requeue_delayed_entity(se);
+				requeue_delayed_entity(rq, se);
 			break;
 		}
 		cfs_rq = cfs_rq_of(se);
-- 
2.40.1

On 11/27/2025 10:33 AM, Huang Shijie wrote:
> When a delay-dequeue task is woken and requeued back, it may
> becomes eligible, and changes the CPU idle status,
> so we need to update the rq->avg_idle for it.
> 
> This patch adds a new parameter for requeue_delayed_entity(),
> and updates the rq->avg_idle as needed.

Can't this be solved by moving update_rq_avg_idle() into
enqueue_task() in the previous patch? The only path that can
reenqueue a delayed task from ttwu_runnable() calls
enqueue_task() with ENQUEUE_DELAYED.

-- 
Thanks and Regards,
Prateek

On 27/11/2025 13:51, K Prateek Nayak wrote:
> Can't this be solved by moving update_rq_avg_idle() into
> enqueue_task() in the previous patch? The only path that can

No problem, I can merge this patch into previous patch.


Thanks

Huang Shijie