The following commit has been merged into the sched/core branch of tip:
Commit-ID: ff1de90dd7a69ef43586683535ad87ab899a1214
Gitweb: https://git.kernel.org/tip/ff1de90dd7a69ef43586683535ad87ab899a1214
Author: Yury Norov (NVIDIA) <yury.norov@gmail.com>
AuthorDate: Sat, 06 Dec 2025 23:05:42 -05:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Thu, 08 Jan 2026 12:43:56 +01:00
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
---
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 7377f91..64275d7 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 */