Re: [PATCH v4 7/7] selftests: prctl: introduce tests for disabling THPs except for madvise

[David Hildenbrand <david@redhat.com>]

>> +
>> +FIXTURE_SETUP(prctl_thp_disable_except_madvise)
>> +{
>> +	if (!thp_available())
>> +		SKIP(return, "Transparent Hugepages not available\n");
>> +
>> +	self->pmdsize = read_pmd_pagesize();
>> +	if (!self->pmdsize)
>> +		SKIP(return, "Unable to read PMD size\n");
>> +
>> +	if (prctl(PR_SET_THP_DISABLE, 1, PR_THP_DISABLE_EXCEPT_ADVISED, NULL, NULL))
>> +		SKIP(return, "Unable to set PR_THP_DISABLE_EXCEPT_ADVISED\n");
> 
> This should be a test fail I think, as the only ways this could fail are
> invalid flags, or failure to obtain an mmap write lock.

Running a kernel that does not support it?

We could check the errno to distinguish I guess.

-- 
Cheers,

David / dhildenb