Re: [PATCH v4 3/9] mm: pagewalk: Don't split transhuge pmds when a pmd_entry is present

[Thomas HellstrÃm (VMware)]

On 10/9/19 6:21 PM, Linus Torvalds wrote:
> On Wed, Oct 9, 2019 at 8:27 AM Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> wrote:
> > Do we have any current user that expect split_huge_pmd() in this scenario.
> No. There are no current users of the pmd callback and the pte
> callback at all, that I could find.
>
> But it looks like the new drm use does want a "I can't handle the
> hugepage, please split it and I'll fo the ptes instead".
Nope, it handles the hugepages by ignoring them, since they should be 
read-only, but if pmd_entry() was called with something else than a 
hugepage, then it requests the fallback, but never a split.

/Thomas