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

[Baolin Wang]

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.