linux-kernel - [PATCH 24/49] mm/vmstat: replace cpumask_weight with cpumask

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Date:   Thu, 10 Feb 2022 14:49:08 -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, linux-mm@...ck.org
Subject: [PATCH 24/49] mm/vmstat: replace cpumask_weight with cpumask_empty where appropriate

mm/vmstat.c 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>
---
 mm/vmstat.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/vmstat.c b/mm/vmstat.c
index d5cc8d739fac..27a94afd4ee5 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -2041,7 +2041,7 @@ static void __init init_cpu_node_state(void)
 	int node;
 
 	for_each_online_node(node) {
-		if (cpumask_weight(cpumask_of_node(node)) > 0)
+		if (!cpumask_empty(cpumask_of_node(node)))
 			node_set_state(node, N_CPU);
 	}
 }
@@ -2068,7 +2068,7 @@ static int vmstat_cpu_dead(unsigned int cpu)
 
 	refresh_zone_stat_thresholds();
 	node_cpus = cpumask_of_node(node);
-	if (cpumask_weight(node_cpus) > 0)
+	if (!cpumask_empty(node_cpus))
 		return 0;
 
 	node_clear_state(node, N_CPU);
-- 
2.32.0