Re: [PATCH v2 2/7] mm/khugepaged: extract young page check into collapse_is_referenced() helper

[Nico Pache]

On Thu, Jul 30, 2026 at 6:16 AM David Hildenbrand (Arm)
<david@xxxxxxxxxx> wrote:
>
> On 7/30/26 09:52, Wei Yang wrote:
> > On Wed, Jul 29, 2026 at 11:47:00AM +0200, David Hildenbrand (Arm) wrote:
> >> On 7/15/26 04:59, Nico Pache wrote:
> >>> This change deduplicates the "is this PTE/folio referenced enough to be
> >>> considered for a collapse" condition that was repeated in both
> >>> __collapse_huge_page_isolate() and collapse_scan_pmd(), extracting it into
> >>> a single inline helper function.
> >>>
> >>> Also move the comment and use it as the function header. While we are at
> >>> it, updated the comment to clarify that a young pte is a recently accessed
> >>> one.
> >>>
> >>> Acked-by: Usama Arif <usama.arif@xxxxxxxxx>
> >>> Signed-off-by: Nico Pache <npache@xxxxxxxxxx>
> >>> ---
> >>
> >> Also, do we really need this (badly named :) ) helper given that there will only
> >> be a single invocation after #5?
> >>
> >
> > Hi, David
> >
> > I see collapse_is_referenced() is invoked by collapse_scan_pmd() and
> > __collapse_huge_page_isolate() after applying the whole series.
> >
> > I didn't see #5 refactor this out. Or I missed something?
>
> Looks like I was daydreaming when skimming #5 :D

Yeah it does get utilized twice :)

Regarding the naming, do you have a better suggestion? I had
collapse_is_young before...

Perhaps pte_is_referenced()? or _is_young()?

Cheers,
-- Nico

>
> --
> Cheers,
>
> David
>