linux-kernel - [PATCH] sched/core: Remove double update_rq_clock() in __set_cpus_allowed_ptr

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Message-Id: <20251029093655.31252-1-jiahao.kernel@gmail.com>
Date: Wed, 29 Oct 2025 17:36:55 +0800
From: Hao Jia <jiahao.kernel@...il.com>
To: mingo@...hat.com,
	peterz@...radead.org,
	mingo@...nel.org,
	juri.lelli@...hat.com,
	vincent.guittot@...aro.org,
	dietmar.eggemann@....com,
	rostedt@...dmis.org,
	bsegall@...gle.com,
	mgorman@...e.de,
	vschneid@...hat.com,
	kprateek.nayak@....com
Cc: linux-kernel@...r.kernel.org,
	Hao Jia <jiahao1@...iang.com>
Subject: [PATCH] sched/core: Remove double update_rq_clock() in __set_cpus_allowed_ptr_locked()

From: Hao Jia <jiahao1@...iang.com>

Since commit d4c64207b88a ("sched: Cleanup the sched_change NOCLOCK usage"),
update_rq_clock() is called in do_set_cpus_allowed() -> sched_change_begin()
to update the rq clock. This results in a duplicate call update_rq_clock()
in __set_cpus_allowed_ptr_locked().

While holding the rq lock and before calling do_set_cpus_allowed(),
there is nothing that depends on an updated rq_clock.

Therefore, remove the redundant update_rq_clock() in
__set_cpus_allowed_ptr_locked() to avoid the warning about double
rq clock updates.

Fixes: d4c64207b88a ("sched: Cleanup the sched_change NOCLOCK usage")
Signed-off-by: Hao Jia <jiahao1@...iang.com>
---
 kernel/sched/core.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 1842285eac1e..1123cd0ddffb 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2999,8 +2999,6 @@ static int __set_cpus_allowed_ptr_locked(struct task_struct *p,
 	unsigned int dest_cpu;
 	int ret = 0;

-	update_rq_clock(rq);
-
 	if (kthread || is_migration_disabled(p)) {
 		/*
 		 * Kernel threads are allowed on online && !active CPUs,
-- 
2.34.1