Re: [PATCH 1/2] kselftest: mm: prevent random failure of huge page split for khugepaged

From: Yeoreum Yun

Date: Thu Aug 20 2026 - 17:24:13 EST


On Thu, Aug 20, 2026 at 03:51:34PM -0400, Zi Yan wrote:
> On Thu Aug 20, 2026 at 3:40 PM EDT, Yeoreum Yun wrote:
> > There're some random failure for split_huge_page_test when khugepaged
> > collapses pages into pmd again which had split by the test.
> >
> > Prevent the khugepaged's collapses for split page by setting the
> > mapped pmd-huge-page with MADV_NOHUGEPAGE before split.
>
> Why not disable khugepaged using APIs from hugepage_setting.h?

Well, this also works with hugepage_save_settings() and write the
khugepaged/scan_sleep_millisecs with the maximum integer.

I don't have a strong opinion but since it seems more hackish way to
change scan_sllep_millisecs, I use madvise() with MADV_NOHUGEPATE.

Would it be better to change using APIs in hugepage_setting,h?

--
Sincerely,
Yeoreum Yun