Re: [PATCH v2 2/2] cgroup/cpuset: Add test cases for sibling CPU exclusion on partition update
From: Waiman Long
Date: Wed May 27 2026 - 14:08:53 EST
On 5/27/26 3:05 AM, Sun Shaojie wrote:
When sibling CPU exclusion occurs, a partition's effective_xcpus may beReviewed-by: Waiman Long <longman@xxxxxxxxxx>
a subset of its user_xcpus. The partcmd_update path must use
effective_xcpus instead of user_xcpus when calculating CPUs to return
to or request from the parent.
Add two test cases to verify this behavior:
1) Narrowing cpuset.cpus to only the sibling-excluded CPUs should not
return CPUs to parent that the partition never actually owned.
2) Expanding cpuset.cpus after a sibling becomes a member should
correctly request the additional CPUs from parent.
Co-developed-by: Zhang Guopeng <zhangguopeng@xxxxxxxxxx>
Signed-off-by: Zhang Guopeng <zhangguopeng@xxxxxxxxxx>
Signed-off-by: Sun Shaojie <sunshaojie@xxxxxxxxxx>
---
tools/testing/selftests/cgroup/test_cpuset_prs.sh | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
index a56f4153c64d..683b05062810 100755
--- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh
+++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
@@ -492,6 +492,16 @@ REMOTE_TEST_MATRIX=(
" C1-5:P1 . C1-4:P1 C2-3 . . \
. . . P1 . . p1:5|c11:1-4|c12:5 \
p1:P1|c11:P1|c12:P-1"
+ # Narrowing cpuset.cpus to previously sibling-excluded CPUs should
+ # not return CPUs that were never actually owned.
+ " C1-4:P1 . C1-2:P1 C1-3:P2 . . \
+ . . . C3 . . p1:4|c11:1-2|c12:3 \
+ p1:P1|c11:P1|c12:P2 3"
+ # Expanding cpuset.cpus to include a previously sibling-excluded CPU
+ # after the sibling has become a member should correctly request it.
+ " C1-4:P1 . C1-2:P1 C1-3:P2 . . \
+ . . P0 C2-3 . . p1:1,4|c11:1|c12:2-3 \
+ p1:P1|c11:P0|c12:P2 2-3"
)
#