linux-kernel - [PATCH 47/54] sched: replace cpumask_weight with cpumask_weight

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Message-Id: <20220123183925.1052919-48-yury.norov@gmail.com>
Date:   Sun, 23 Jan 2022 10:39:18 -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 47/54] sched: replace cpumask_weight with cpumask_weight_eq where appropriate

kernel/sched code uses cpumask_weight() to compare the weight of
cpumask with a given number. We can do it more efficiently with
cpumask_weight_eq because conditional cpumask_weight may stop
traversing the cpumask earlier, as soon as condition is met.

Signed-off-by: Yury Norov <yury.norov@...il.com>
---
 kernel/sched/core.c     | 8 ++++----
 kernel/sched/topology.c | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 918d0bdc2ea8..7494f51a3608 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6006,7 +6006,7 @@ static void sched_core_cpu_starting(unsigned int cpu)
 	WARN_ON_ONCE(rq->core != rq);
 
 	/* if we're the first, we'll be our own leader */
-	if (cpumask_weight(smt_mask) == 1)
+	if (cpumask_weight_eq(smt_mask, 1))
 		goto unlock;
 
 	/* find the leader */
@@ -6047,7 +6047,7 @@ static void sched_core_cpu_deactivate(unsigned int cpu)
 	sched_core_lock(cpu, &flags);
 
 	/* if we're the last man standing, nothing to do */
-	if (cpumask_weight(smt_mask) == 1) {
+	if (cpumask_weight_eq(smt_mask, 1)) {
 		WARN_ON_ONCE(rq->core != rq);
 		goto unlock;
 	}
@@ -9045,7 +9045,7 @@ int sched_cpu_activate(unsigned int cpu)
 	/*
 	 * When going up, increment the number of cores with SMT present.
 	 */
-	if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
+	if (cpumask_weight_eq(cpu_smt_mask(cpu), 2))
 		static_branch_inc_cpuslocked(&sched_smt_present);
 #endif
 	set_cpu_active(cpu, true);
@@ -9120,7 +9120,7 @@ int sched_cpu_deactivate(unsigned int cpu)
 	/*
 	 * When going down, decrement the number of cores with SMT present.
 	 */
-	if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
+	if (cpumask_weight_eq(cpu_smt_mask(cpu), 2))
 		static_branch_dec_cpuslocked(&sched_smt_present);
 
 	sched_core_cpu_deactivate(cpu);
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 8478e2a8cd65..79395571599f 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -169,7 +169,7 @@ static const unsigned int SD_DEGENERATE_GROUPS_MASK =
 
 static int sd_degenerate(struct sched_domain *sd)
 {
-	if (cpumask_weight(sched_domain_span(sd)) == 1)
+	if (cpumask_weight_eq(sched_domain_span(sd), 1))
 		return 1;
 
 	/* Following flags need at least 2 groups */
-- 
2.30.2