linux-kernel - [PATCH 23/54] sched: replace cpumask_weight with cpumask

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Message-Id: <20220123183925.1052919-24-yury.norov@gmail.com>
Date:   Sun, 23 Jan 2022 10:38:54 -0800
From:   Yury Norov <yury.norov@...il.com>
To:     Yury Norov <yury.norov@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        David Laight <David.Laight@...lab.com>,
        Joe Perches <joe@...ches.com>, Dennis Zhou <dennis@...nel.org>,
        Emil Renner Berthing <kernel@...il.dk>,
        Nicholas Piggin <npiggin@...il.com>,
        Matti Vaittinen <matti.vaittinen@...rohmeurope.com>,
        Alexey Klimov <aklimov@...hat.com>,
        linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
        Daniel Bristot de Oliveira <bristot@...hat.com>
Subject: [PATCH 23/54] sched: replace cpumask_weight with cpumask_empty where appropriate

In some places, kernel/sched code calls cpumask_weight() to check if
any bit of a given cpumask is set. We can do it more efficiently with
cpumask_empty() because cpumask_empty() stops traversing the cpumask as
soon as it finds first set bit, while cpumask_weight() counts all bits
unconditionally.

Signed-off-by: Yury Norov <yury.norov@...il.com>
---
 kernel/sched/core.c     | 2 +-
 kernel/sched/topology.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 2e4ae00e52d1..918d0bdc2ea8 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8707,7 +8707,7 @@ int cpuset_cpumask_can_shrink(const struct cpumask *cur,
 {
 	int ret = 1;
 
-	if (!cpumask_weight(cur))
+	if (cpumask_empty(cur))
 		return ret;
 
 	ret = dl_cpuset_cpumask_can_shrink(cur, trial);
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index d201a7052a29..8478e2a8cd65 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -74,7 +74,7 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
 			break;
 		}
 
-		if (!cpumask_weight(sched_group_span(group))) {
+		if (cpumask_empty(sched_group_span(group))) {
 			printk(KERN_CONT "\n");
 			printk(KERN_ERR "ERROR: empty group\n");
 			break;
-- 
2.30.2