Commit 1087ad4e authored by Yury Norov's avatar Yury Norov Committed by Peter Zijlstra
Browse files

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: default avatarYury Norov <yury.norov@gmail.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220210224933.379149-23-yury.norov@gmail.com
parent 3624ba7b

kernel/sched/core.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

kernel/sched/topology.c

+1 −1
Original line number Diff line number Diff line
@@ -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;