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From: Xuewen Yan <xuewen.yan@unisoc.com>
To: <vincent.guittot@linaro.org>, <peterz@infradead.org>,
	<mingo@redhat.com>, <juri.lelli@redhat.com>,
	<dietmar.eggemann@arm.com>, <rostedt@goodmis.org>,
	<bsegall@google.com>, <mgorman@suse.de>, <vschneid@redhat.com>
Cc: <linux-kernel@vger.kernel.org>, <ke.wang@unisoc.com>,
	<di.shen@unisoc.com>, <xuewen.yan94@gmail.com>
Subject: [RFC PATCH V2 2/3] sched/fair: Do not consider the sched-delayed task when yield
Date: Mon, 3 Mar 2025 18:52:40 +0800	[thread overview]
Message-ID: <20250303105241.17251-3-xuewen.yan@unisoc.com> (raw)
In-Reply-To: <20250303105241.17251-1-xuewen.yan@unisoc.com>

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@unisoc.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


  parent reply	other threads:[~2025-03-03 10:53 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-03 10:52 [RFC PATCH V2 0/3] sched/fair: Fix nr-running vs delayed-dequeue Xuewen Yan
2025-03-03 10:52 ` [RFC PATCH V2 1/3] sched/fair: Fixup-wake_up_sync-vs-DELAYED_DEQUEUE Xuewen Yan
2025-03-19  9:05   ` Tianchen Ding
2025-03-19  9:34   ` Vincent Guittot
2025-05-20  6:00     ` Xuewen Yan
2025-05-21 12:06   ` [tip: sched/core] sched/fair: Fixup wake_up_sync() vs DELAYED_DEQUEUE tip-bot2 for Xuewen Yan
2025-03-03 10:52 ` Xuewen Yan [this message]
2025-03-03 10:52 ` [RFC PATCH V2 3/3] sched: Do not consider the delayed task when cpu is about to enter idle Xuewen Yan
2025-03-03 12:00 ` [RFC PATCH V2 0/3] sched/fair: Fix nr-running vs delayed-dequeue Peter Zijlstra
2025-03-04  1:56   ` Xuewen Yan
2025-03-05  8:17     ` Vincent Guittot
2025-03-06  7:33       ` Xuewen Yan

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