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From: Yury Norov <yury.norov@gmail.com>
To: Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
	Valentin Schneider <vschneid@redhat.com>,
	linux-kernel@vger.kernel.org
Cc: Yury Norov <yury.norov@gmail.com>
Subject: [PATCH] sched/fair: use cpumask_weight_and() in sched_balance_find_dst_group()
Date: Wed, 10 Sep 2025 23:44:52 -0400	[thread overview]
Message-ID: <20250911034454.494852-1-yury.norov@gmail.com> (raw)

From: Yury Norov (NVIDIA) <yury.norov@gmail.com>

In the group_has_spare case, the function creates a temporary cpumask
to just calculate weight of (p->cpus_ptr & sched_group_span(local)).

We've got a dedicated helper for it.

Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
---
 kernel/sched/fair.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 7229339cbb1b..4ec012912cd1 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -10821,10 +10821,9 @@ sched_balance_find_dst_group(struct sched_domain *sd, struct task_struct *p, int
 			 * take care of it.
 			 */
 			if (p->nr_cpus_allowed != NR_CPUS) {
-				struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_rq_mask);
-
-				cpumask_and(cpus, sched_group_span(local), p->cpus_ptr);
-				imb_numa_nr = min(cpumask_weight(cpus), sd->imb_numa_nr);
+				unsigned w = cpumask_weight_and(p->cpus_ptr,
+								sched_group_span(local));
+				imb_numa_nr = min(w, sd->imb_numa_nr);
 			}
 
 			imbalance = abs(local_sgs.idle_cpus - idlest_sgs.idle_cpus);
-- 
2.43.0


             reply	other threads:[~2025-09-11  3:44 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-11  3:44 Yury Norov [this message]
2025-09-11  6:52 ` [PATCH] sched/fair: use cpumask_weight_and() in sched_balance_find_dst_group() K Prateek Nayak
2025-09-11  8:50 ` Vincent Guittot
2025-09-11  8:58 ` Fernand Sieber

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