[cgroup/for-6.20 PATCH 1/4] cgroup/cpuset: Streamline rm_siblings_excl_cpus()

From: Waiman Long
Date: Thu Dec 25 2025 - 02:32:28 EST


If exclusive_cpus is set, effective_xcpus must be a subset of
exclusive_cpus. Currently, rm_siblings_excl_cpus() checks both
exclusive_cpus and effective_xcpus connectively. It is simpler
to check only exclusive_cpus if non-empty or just effective_xcpus
otherwise.

No functional change is expected.

Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
---
kernel/cgroup/cpuset.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 221da921b4f9..3d2d28f0fd03 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -1355,23 +1355,24 @@ static int rm_siblings_excl_cpus(struct cpuset *parent, struct cpuset *cs,
int retval = 0;

if (cpumask_empty(excpus))
- return retval;
+ return 0;

/*
* Exclude exclusive CPUs from siblings
*/
rcu_read_lock();
cpuset_for_each_child(sibling, css, parent) {
+ struct cpumask *sibling_xcpus;
+
if (sibling == cs)
continue;

- if (cpumask_intersects(excpus, sibling->exclusive_cpus)) {
- cpumask_andnot(excpus, excpus, sibling->exclusive_cpus);
- retval++;
- continue;
- }
- if (cpumask_intersects(excpus, sibling->effective_xcpus)) {
- cpumask_andnot(excpus, excpus, sibling->effective_xcpus);
+ sibling_xcpus = cpumask_empty(sibling->exclusive_cpus)
+ ? sibling->effective_xcpus
+ : sibling->exclusive_cpus;
+
+ if (cpumask_intersects(excpus, sibling_xcpus)) {
+ cpumask_andnot(excpus, excpus, sibling_xcpus);
retval++;
}
}
--
2.52.0