[PATCH 47/54] sched: replace cpumask_weight with cpumask_weight_eq where appropriate

From: Yury Norov <yury.norov@gmail.com>
To: "Yury Norov" <yury.norov@gmail.com>,
	"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
	"Rasmus Villemoes" <linux@rasmusvillemoes.dk>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Michał Mirosław" <mirq-linux@rere.qmqm.pl>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"David Laight" <David.Laight@aculab.com>,
	"Joe Perches" <joe@perches.com>,
	"Dennis Zhou" <dennis@kernel.org>,
	"Emil Renner Berthing" <kernel@esmil.dk>,
	"Nicholas Piggin" <npiggin@gmail.com>,
	"Matti Vaittinen" <matti.vaittinen@fi.rohmeurope.com>,
	"Alexey Klimov" <aklimov@redhat.com>,
	linux-kernel@vger.kernel.org, "Ingo Molnar" <mingo@redhat.com>,
	"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>,
	"Daniel Bristot de Oliveira" <bristot@redhat.com>
Subject: [PATCH 47/54] sched: replace cpumask_weight with cpumask_weight_eq where appropriate
Date: Sun, 23 Jan 2022 10:39:18 -0800	[thread overview]
Message-ID: <20220123183925.1052919-48-yury.norov@gmail.com> (raw)
In-Reply-To: <20220123183925.1052919-1-yury.norov@gmail.com>

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@gmail.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

