Re: [PATCH-next v2 1/5] selftests/cgroup: Fix "test_cpuset_prs.sh -v" failures

[Ridong Chen <ridong.chen@linux.dev>]

On 11/10/2026 3:09 AM, Waiman Long wrote:
> When the -v option is used to run test_cpuset_prs.sh, it activates the
> use of sched-debug to determine the set of isolated CPUs which will
> also consider 1-CPU partition as being isolated though they will not be
> reflected in "cpuset.cpus.isolated". As a result, some of the expected
> isolated CPUs values have 2 different set of values to correspond to
> these two ways of determining isolated CPUs.
> 
> Commit 6e4834ba8986 ("cgroup/cpuset: Fix incorrect CPU accounting with
> parent's effective_xcpus expansion") introduces some new test cases
> which fail when the -v option is used. Update the test cases to make
> them pass with the -v option as well.
> 
> Also remove an obsolete comment in update_parent_effective_cpumask()
> of cpuset.c.
> 
> Reported-by: Tejun Heo <tj@kernel.org>
> Link: https://lore.kernel.org/lkml/886a562b52b1c5094142d547a8336457@kernel.org
> Fixes: 362212853cd0 ("cgroup/cpuset: Fix incorrect CPU accounting with parent's effective_xcpus expansion")
> Signed-off-by: Waiman Long <longman@redhat.com>
> ---
>   kernel/cgroup/cpuset.c                            |  6 ------
>   tools/testing/selftests/cgroup/test_cpuset_prs.sh | 13 ++++++++-----
>   2 files changed, 8 insertions(+), 11 deletions(-)
> 
> diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
> index 85e5b529d144..6074327c3477 100644
> --- a/kernel/cgroup/cpuset.c
> +++ b/kernel/cgroup/cpuset.c
> @@ -2164,12 +2164,6 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd,
>   			else
>   				part_error = PERR_NOTEXCL;
>   		}
> -		/*
> -		 * When both cs and parent remain valid, parent's
> -		 * compute_partition_effective_cpumask() call would have removed
> -		 * cs's effective_xcpus from the parent's effective_cpus. So
> -		 * there is no need to adjust parent's effective_cpus here.
> -		 */
>   	}
>   
>   write_error:
> diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
> index 32e1e44fa0b1..2d4744f2d6ac 100755
> --- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh
> +++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
> @@ -540,16 +540,19 @@ TEST_MATRIX=(
>   
>   	# The extra CPUs gained by a child partition when its parent expands the
>   	# exclusive CPUs have to be taken away from the parent.
> -	" C2-6:X2-5:P1 CX3-6:P1 \
> -	                    .      .    X2-6     .      .      .     0 A1:2|A2:3-6|XA2:3-6 A1:P1|A2:P1 ."
> -	" C2-6:X2-5:P1 CX3-6:P2 \
> -	                    .      .    X2-6     .      .      .     0 A1:2|A2:3-6|XA2:3-6 A1:P1|A2:P2 3-6"
> +	" C2-6:X2-5:P1 CX4-6:P1 \
> +	                    .      .    X2-6     .      .      .     0 A1:2-3|A2:4-6|XA2:4-6 \
> +								       A1:P1|A2:P1 ."
> +	" C2-6:X2-5:P1 CX4-6:P2 \
> +	                    .      .    X2-6     .      .      .     0 A1:2-3|A2:4-6|XA2:4-6 \
> +								       A1:P1|A2:P2 4-6"
>   
>   	# Both expansion and contraction of parent's effective_xcpus will be
>   	# correctly handled in child partition and the child can be invalidated
>   	# if a populated parent could lose all its effective_cpus.
>   	" C2-6:X2-5:P1 CX3,5-6:P2 \
> -	                    .      .    X4-6     .      .      .     0 A1:4|A2:5-6|XA2:5-6 A1:P1|A2:P2 5-6"
> +	                    .      .    X4-6     .      .      .     0 A1:4|A2:5-6|XA2:5-6 \
> +								       A1:P1|A2:P2 4-6|5-6"
>   	" C2-6:X2-5:P1 CX3-6:P2 \
>   	                    .      .   T:X4-6    .      .      .     0 A1:4-6|A2:4-6 A1:P1|A2:P-2 ."
>   

The commit message still refers to commit 6e4834ba8986, which isn't in
next tree. It should be 362212853cd0 ?

I applied the whole series on top of next-20261109 and ran
test_cpuset_prs.sh with and without -v as well as test_cpuset on an
8-CPU VM. All tests passed and there is no warning in dmesg.


Reviewed-by: Ridong Chen <ridong.chen@linux.dev>
Tested-by: Ridong Chen <ridong.chen@linux.dev>

-- 
Best regards
Ridong