linux-kernel - [RFC PATCH V2 2/3] sched/fair: Do not consider the sched-delayed task when yield

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Message-ID: <20250303105241.17251-3-xuewen.yan@unisoc.com>
Date: Mon, 3 Mar 2025 18:52:40 +0800
From: Xuewen Yan <xuewen.yan@...soc.com>
To: <vincent.guittot@...aro.org>, <peterz@...radead.org>, <mingo@...hat.com>,
        <juri.lelli@...hat.com>, <dietmar.eggemann@....com>,
        <rostedt@...dmis.org>, <bsegall@...gle.com>, <mgorman@...e.de>,
        <vschneid@...hat.com>
CC: <linux-kernel@...r.kernel.org>, <ke.wang@...soc.com>, <di.shen@...soc.com>,
        <xuewen.yan94@...il.com>
Subject: [RFC PATCH V2 2/3] sched/fair: Do not consider the sched-delayed task when yield

When task call sched_yield, if there is only one task in rq,
it is no need to yield, however now, the rq->nr_running include
the sched-delayed tasks which are indeed not runnable tasks.
So sub the sched-delayed tasks when check the nr-running.

Fixes: 152e11f6df29 ("sched/fair: Implement delayed dequeue")
Signed-off-by: Xuewen Yan <xuewen.yan@...soc.com>
---
 kernel/sched/fair.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a354f29c4f6f..8797f6872155 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8992,7 +8992,7 @@ static void yield_task_fair(struct rq *rq)
 	/*
 	 * Are we the only task in the tree?
 	 */
-	if (unlikely(rq->nr_running == 1))
+	if (unlikely((rq->nr_running - cfs_h_nr_delayed(rq)) == 1))
 		return;
 
 	clear_buddies(cfs_rq, se);
-- 
2.25.1