Re: [PATCH] selftests/mm: Restore default nr_hugepages value during cleanup in hugetlb_reparenting_test.sh

[Dev Jain <dev.jain@arm.com>]

On 15/04/25 12:28 pm, Anshuman Khandual wrote:
> 
> 
> On 4/10/25 15:37, Donet Tom wrote:
>> During cleanup, the value of /proc/sys/vm/nr_hugepages is currently
>> being set to 0. At the end of the test, if all tests pass, the
>> original nr_hugepages value is restored. However, if any test fails,
>> it remains set to 0.
>>
>> With this patch, we ensure that the original nr_hugepages value is
>> restored during cleanup, regardless of whether the test passes or fails.
>>
>> Fixes: 29750f71a9b4 ("hugetlb_cgroup: add hugetlb_cgroup reservation tests")
> Although this change makes sense as an improvement or a cleanup but
> not sure if this also deserves a Fixes: tag as well.

IMHO it deserves a Fixes tag, the tests should always cleanly exit 
without changing system state. It may or may not cause an actual 
problem, so let's be proactive : )

> 
>> Signed-off-by: Donet Tom <donettom@linux.ibm.com>
>> ---
>>   tools/testing/selftests/mm/hugetlb_reparenting_test.sh | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/tools/testing/selftests/mm/hugetlb_reparenting_test.sh b/tools/testing/selftests/mm/hugetlb_reparenting_test.sh
>> index 11f9bbe7dc22..114875a2b018 100755
>> --- a/tools/testing/selftests/mm/hugetlb_reparenting_test.sh
>> +++ b/tools/testing/selftests/mm/hugetlb_reparenting_test.sh
>> @@ -56,7 +56,7 @@ function cleanup() {
>>     rmdir "$CGROUP_ROOT"/a/b 2>/dev/null
>>     rmdir "$CGROUP_ROOT"/a 2>/dev/null
>>     rmdir "$CGROUP_ROOT"/test1 2>/dev/null
>> -  echo 0 >/proc/sys/vm/nr_hugepages
>> +  echo $nr_hugepgs >/proc/sys/vm/nr_hugepages
>>     set -e
>>   }
>>   
>