Re: [RFC PATCH v2 33/47] userfaultfd: add UFFD_FEATURE_MINOR_HUGETLBFS_HGM

From: Peter Xu
Date: Thu Dec 22 2022 - 09:31:26 EST


On Wed, Dec 21, 2022 at 08:24:45PM -0500, James Houghton wrote:
> Not sure what the best name for this flag is either. MADV_ENABLE_HGM
> sounds ok. MADV_HUGETLB_HGM or MADV_HUGETLB_SMALL_PAGES could work
> too. No need to figure it out now.

One more option to consider is MADV_SPLIT (hopefully to be more generic).

We already decided to reuse thp MADV_COLLAPSE, we can also introduce
MADV_SPLIT and leave thp for later if it can be anything helpful (I
remember we used to discuss this for thp split).

For hugetlb one SPLIT should enable hgm advise bit on the vma forever.

Thanks,

--
Peter Xu