Re: [PATCH-next v2 6/6] selftests/cgroup: Skip test_cpuset_prs.sh test if some required CPUs are offline

[Waiman Long <longman@redhat.com>]

On 10/11/26 5:00 AM, Guopeng Zhang wrote:
>
> 在 2026/10/11 06:19, Waiman Long 写道:
>> The test_cpuset_prs.sh test assumes that all the relevant CPUs being
>> tested are online. If some of them are offline, some of the test cases
>> may fail. So skip the test if the required CPUs are either offline or
>> not present.
>>
>> Signed-off-by: Waiman Long <longman@redhat.com>
>> ---
>>   .../selftests/cgroup/test_cpuset_prs.sh       | 20 +++++++++++++++++++
>>   1 file changed, 20 insertions(+)
>>
>> diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
>> index 3d392e8c66aa..f57971ebb90e 100755
>> --- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh
>> +++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
>> @@ -118,6 +118,26 @@ TEST_ISOLCPUS=
>>   		skip_test "Current isolated CPUs ($CURRENT_ISOLCPUS) don't match boot isolated CPUs!"
>>   }
>>   
>> +#
>> +# This test assumes that all the relevant CPUs being tested are online.
>> +# If some of them are offline, some of the tests may fail. So we are going to
>> +# skip running this test script if some of the required CPUs may be offline.
>> +# The required CPUs include CPUs 0-7 and the first boot time isolated CPU if
>> +# present. However the check below is not exhaustive and can be a false
>> +# positive, but users should not run this test if some CPUs are offline.
>> +#
>> +ONLINE_CPUS=$(cat /sys/devices/system/cpu/online | sed -e "s/,.*//")
>> +ONLINE_FIRST=$(echo $ONLINE_CPUS | sed -e "s/-.*//")
>> +ONLINE_LAST=$(echo $ONLINE_CPUS | sed -e "s/.*-//")
>> +if [[ -n "$FIRST_ISOLCPUS" ]]
>> +then
>> +	LAST_REQUIRED_CPU=$FIRST_ISOLCPUS
>> +else
>> +	LAST_REQUIRED_CPU=7
>> +fi
>> +[[ $ONLINE_FIRST != 0 || $ONLINE_LAST -lt $LAST_REQUIRED_CPU ]] &&
>> +	skip_test "Some of the required CPUs are offline or not present!"
>> +
> Could this check run before the setup that creates the test cgroup and
> changes sched/verbose?
>
> skip_test() exits directly, and the cleanup trap hasn't been installed
> here. We have already created test; with -v, sched/verbose has also been
> set to Y. This exit leaves the cgroup behind and bypasses restoring
> verbose.

Good point. I am going to move the trap statement earlier to make sure 
that it will be run when there is an early abort.

Cheers,
Longman