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Wed, 10 Sep 2025 19:34:29 -0700 (PDT) Received: from localhost ([216.228.125.130]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-77607b392fcsm270133b3a.87.2025.09.10.19.34.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 Sep 2025 19:34:29 -0700 (PDT) From: Yury Norov To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , linux-kernel@vger.kernel.org Cc: Yury Norov Subject: [PATCH] sched: fair: drop useless cpumask_empty() in find_energy_efficient_cpu() Date: Wed, 10 Sep 2025 22:34:25 -0400 Message-ID: <20250911023426.457745-1-yury.norov@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Yury Norov (NVIDIA) cpumask_empty() call is O(N) and useless, because the previous cpumask_and() returns false for empty 'cpus'. Signed-off-by: Yury Norov (NVIDIA) Reviewed-by: K Prateek Nayak Reviewed-by: Madadi Vineeth Reddy Reviewed-by: Vincent Guittot --- kernel/sched/fair.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index b173a059315c..7229339cbb1b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8320,9 +8320,7 @@ static int find_energy_efficient_cpu(struct task_stru= ct *p, int prev_cpu) int max_spare_cap_cpu =3D -1; int fits, max_fits =3D -1; =20 - cpumask_and(cpus, perf_domain_span(pd), cpu_online_mask); - - if (cpumask_empty(cpus)) + if (!cpumask_and(cpus, perf_domain_span(pd), cpu_online_mask)) continue; =20 /* Account external pressure for the energy estimation */ --=20 2.43.0