linux-kernel - [tip: sched/core] sched: replace cpumask_weight with cpumask

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Message-ID: <164512421465.16921.1322444581830816438.tip-bot2@tip-bot2>
Date:   Thu, 17 Feb 2022 18:56:54 -0000
From:   "tip-bot2 for Yury Norov" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Yury Norov <yury.norov@...il.com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: sched/core] sched: replace cpumask_weight with cpumask_empty
 where appropriate

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     1087ad4e3f88c474b8134a482720782922bf3fdf
Gitweb:        https://git.kernel.org/tip/1087ad4e3f88c474b8134a482720782922bf3fdf
Author:        Yury Norov <yury.norov@...il.com>
AuthorDate:    Thu, 10 Feb 2022 14:49:06 -08:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Wed, 16 Feb 2022 15:57:53 +01:00

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>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Link: https://lkml.kernel.org/r/20220210224933.379149-23-yury.norov@gmail.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 1d863d7..c620aab 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8708,7 +8708,7 @@ 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 e6cd559..1c84b48 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;