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

[Donet Tom <donettom@linux.ibm.com>]

On 4/15/25 1:00 PM, Dev Jain wrote:
>
>
> 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 : )
>
Yes, I was thinking the same.

>
>>
>>> 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
>>>   }
>>
>
>