linux-kernel - [tip: sched/urgent] sched/deadline: Avoid double update_rq

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Message-ID: <176851086283.510.1348786970791383617.tip-bot2@tip-bot2>
Date: Thu, 15 Jan 2026 21:01:02 -0000
From: "tip-bot2 for Peter Zijlstra" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Pierre Gondois <pierre.gondois@....com>,
 "Peter Zijlstra (Intel)" <peterz@...radead.org>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: sched/urgent] sched/deadline: Avoid double update_rq_clock()

The following commit has been merged into the sched/urgent branch of tip:

Commit-ID:     4de9ff76067b40c3660df73efaea57389e62ea7a
Gitweb:        https://git.kernel.org/tip/4de9ff76067b40c3660df73efaea57389e62ea7a
Author:        Peter Zijlstra <peterz@...radead.org>
AuthorDate:    Tue, 13 Jan 2026 12:57:14 +01:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Thu, 15 Jan 2026 21:57:52 +01:00

sched/deadline: Avoid double update_rq_clock()

When setup_new_dl_entity() is called from enqueue_task_dl() ->
enqueue_dl_entity(), the rq-clock should already be updated, and
calling update_rq_clock() again is not right.

Move the update_rq_clock() to the one other caller of
setup_new_dl_entity(): sched_init_dl_server().

Fixes: 9f239df55546 ("sched/deadline: Initialize dl_servers after SMP")
Reported-by: Pierre Gondois <pierre.gondois@....com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Tested-by: Pierre Gondois <pierre.gondois@....com>
Link: https://patch.msgid.link/20260113115622.GA831285@noisy.programming.kicks-ass.net
---
 kernel/sched/deadline.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index b7acf74..5d6f3cc 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -752,8 +752,6 @@ static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se)
 	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
 	struct rq *rq = rq_of_dl_rq(dl_rq);
 
-	update_rq_clock(rq);
-
 	WARN_ON(is_dl_boosted(dl_se));
 	WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline));
 
@@ -1839,6 +1837,7 @@ void sched_init_dl_servers(void)
 		rq = cpu_rq(cpu);
 
 		guard(rq_lock_irq)(rq);
+		update_rq_clock(rq);
 
 		dl_se = &rq->fair_server;