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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@gmail.com>
AuthorDate: Thu, 10 Feb 2022 14:49:06 -08:00
Committer: Peter Zijlstra <peterz@infradead.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@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.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;
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