Re: [PATCH v3 1/2] mm: huge_memory: disallow hugepages if the system-wide THP sysfs settings are disabled

[Baolin Wang <baolin.wang@linux.alibaba.com>]

On 2025/6/23 21:54, David Hildenbrand wrote:
> 
>> diff --git a/tools/testing/selftests/mm/khugepaged.c b/tools/testing/ 
>> selftests/mm/khugepaged.c
>> index 4341ce6b3b38..85bfff53dba6 100644
>> --- a/tools/testing/selftests/mm/khugepaged.c
>> +++ b/tools/testing/selftests/mm/khugepaged.c
>> @@ -501,11 +501,7 @@ static void __madvise_collapse(const char *msg, 
>> char *p, int nr_hpages,
>>       printf("%s...", msg);
>> -    /*
>> -     * Prevent khugepaged interference and tests that MADV_COLLAPSE
>> -     * ignores /sys/kernel/mm/transparent_hugepage/enabled
>> -     */
>> -    settings.thp_enabled = THP_NEVER;
>> +    settings.thp_enabled = THP_ALWAYS;
> 
> 
> Would MADVISE mode also work here? If we don't set MADV_HUGEPAGE, then 
> khugepaged should be excluded, correct?

I tried this, but some test cases failed. As I replied to Barry, it's 
because some tests previously set MADV_NOHUGEPAGE, and now there is no 
way to clear the MADV_NOHUGEPAGE flag except by setting MADV_HUGEPAGE.