From: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Date: Sun, 7 Dec 2025 04:05:42 +0000 (-0500)
Subject: sched/fair: Drop useless cpumask_empty() in find_energy_efficient_cpu()
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ff1de90dd7a69ef43586683535ad87ab899a1214;p=thirdparty%2Fkernel%2Flinux.git

sched/fair: Drop useless cpumask_empty() in find_energy_efficient_cpu()

cpumask_empty() call is O(N) and useless because the previous
cpumask_and() returns false for empty 'cpus'. Drop it.

Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Madadi Vineeth Reddy <vineethr@linux.ibm.com>
Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://patch.msgid.link/20251207040543.407695-1-yury.norov@gmail.com
---

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 7377f91175010..64275d75a964d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8359,9 +8359,7 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu)
 		int max_spare_cap_cpu = -1;
 		int fits, max_fits = -1;
 
-		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;
 
 		/* Account external pressure for the energy estimation */