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[188.141.5.72]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43ead33d6d3sm5173020f8f.8.2026.04.15.05.40.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Apr 2026 05:40:47 -0700 (PDT) From: David Carlier To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak Cc: David Carlier , linux-kernel@vger.kernel.org Subject: [PATCH] sched/rt: Use atomic_try_cmpxchg_acquire() in rto_start_trylock() Date: Wed, 15 Apr 2026 13:40:44 +0100 Message-ID: <20260415124045.372307-1-devnexen@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Replace this pattern in rto_start_trylock(): !atomic_cmpxchg_acquire(*ptr, 0, new) ... with the simpler and faster: atomic_try_cmpxchg_acquire(*ptr, &zero, new) The x86 CMPXCHG instruction returns success in the ZF flag, so atomic_try_cmpxchg_acquire() saves a compare after the CMPXCHG. No functional change intended. Signed-off-by: David Carlier --- kernel/sched/rt.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 4ee8faf01441..13ac94899c18 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -2172,7 +2172,8 @@ static int rto_next_cpu(struct root_domain *rd) static inline bool rto_start_trylock(atomic_t *v) { - return !atomic_cmpxchg_acquire(v, 0, 1); + int zero = 0; + return atomic_try_cmpxchg_acquire(v, &zero, 1); } static inline void rto_start_unlock(atomic_t *v) -- 2.53.0