linux-kernel - [PATCH 01/11 v3] sched/fair: Fix sched_can_stop

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Message-ID: <20241202174606.4074512-2-vincent.guittot@linaro.org>
Date: Mon,  2 Dec 2024 18:45:56 +0100
From: Vincent Guittot <vincent.guittot@...aro.org>
To: mingo@...hat.com,
	peterz@...radead.org,
	juri.lelli@...hat.com,
	dietmar.eggemann@....com,
	rostedt@...dmis.org,
	bsegall@...gle.com,
	mgorman@...e.de,
	vschneid@...hat.com,
	linux-kernel@...r.kernel.org
Cc: kprateek.nayak@....com,
	pauld@...hat.com,
	efault@....de,
	luis.machado@....com,
	tj@...nel.org,
	void@...ifault.com,
	Vincent Guittot <vincent.guittot@...aro.org>
Subject: [PATCH 01/11 v3] sched/fair: Fix sched_can_stop_tick() for fair tasks

We can't stop the tick of a rq if there are at least 2 tasks enqueued in
the whole hierarchy and not only at the root cfs rq.

rq->cfs.nr_running tracks the number of sched_entity at one level
whereas rq->cfs.h_nr_running tracks all queued tasks in the
hierarchy.

Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>
---
 kernel/sched/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 1dee3f5ef940..ed95861e9887 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1343,7 +1343,7 @@ bool sched_can_stop_tick(struct rq *rq)
 	if (scx_enabled() && !scx_can_stop_tick(rq))
 		return false;
 
-	if (rq->cfs.nr_running > 1)
+	if (rq->cfs.h_nr_running > 1)
 		return false;
 
 	/*
-- 
2.43.0