linux-kernel - [PATCH v2] sched/topology: remove redundant cpumask_and in init_overlap_sched

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Message-ID: <20210325023140.23456-1-song.bao.hua@hisilicon.com>
Date:   Thu, 25 Mar 2021 15:31:40 +1300
From:   Barry Song <song.bao.hua@...ilicon.com>
To:     <vincent.guittot@...aro.org>, <mingo@...hat.com>,
        <peterz@...radead.org>, <juri.lelli@...hat.com>,
        <dietmar.eggemann@....com>, <rostedt@...dmis.org>,
        <bsegall@...gle.com>, <mgorman@...e.de>
CC:     <valentin.schneider@....com>, <linux-kernel@...r.kernel.org>,
        <linuxarm@...neuler.org>, Barry Song <song.bao.hua@...ilicon.com>,
        "Valentin Schneider" <Valentin.Schneider@....com>
Subject: [PATCH v2] sched/topology: remove redundant cpumask_and in init_overlap_sched_group

mask is built in build_balance_mask() by for_each_cpu(i, sg_span), so
it must be a subset of sched_group_span(sg). Though cpumask_first_and
doesn't lead to a wrong result of balance cpu, it is pointless to do
cpumask_and again.

Signed-off-by: Barry Song <song.bao.hua@...ilicon.com>
Reviewed-by: Valentin Schneider <Valentin.Schneider@....com>
---
 -v2: add reviewed-by of Valentin, thanks!

 kernel/sched/topology.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index f2066d682cd8..d1aec244c027 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -934,7 +934,7 @@ static void init_overlap_sched_group(struct sched_domain *sd,
 	int cpu;
 
 	build_balance_mask(sd, sg, mask);
-	cpu = cpumask_first_and(sched_group_span(sg), mask);
+	cpu = cpumask_first(mask);
 
 	sg->sgc = *per_cpu_ptr(sdd->sgc, cpu);
 	if (atomic_inc_return(&sg->sgc->ref) == 1)
-- 
2.25.1