Re: [PATCH v3 05/18] mm/huge_memory: rename __split_unmapped_folio() to __split_frozen_folio()

[Kairui Song]

On Fri, Aug 28, 2026 at 12:22 AM David Hildenbrand (Arm)
<david@xxxxxxxxxx> wrote:
>
> On 8/27/26 17:06, Kiryl Shutsemau wrote:
> > On Fri, Aug 21, 2026 at 02:55:18AM +0800, Kairui Song via B4 Relay wrote:
> >> From: Kairui Song <kasong@xxxxxxxxxxx>
> >>
> >> The helper splits a folio whose refcount is frozen: the frozen refcount
> >> is the state it relies on, while unmapping is arranged by the caller
> >> beforehand. The old name caused confusion and people may try to call the
> >> helper on non-frozen folios.
> >>
> >> Suggested-by: Zi Yan <ziy@xxxxxxxxxx>
> >> Reviewed-by: Zi Yan <ziy@xxxxxxxxxx>
> >> Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
> >
> > This patch is fine:
> >
> > Reviewed-by: Kiryl Shutsemau (Meta) <kas@xxxxxxxxxx>
> >
> >> @@ -3989,8 +3989,8 @@ static int __folio_freeze_split_unmapped_anon(struct folio *folio, unsigned int
> >>      if (do_lru)
> >>              lruvec = folio_lruvec_lock(folio);
> >>
> >> -    ret = __split_unmapped_folio(folio, new_order, split_at, NULL,
> >> -                                 NULL, split_type);
> >> +    ret = __split_frozen_folio(folio, new_order, split_at, NULL,
> >> +                               NULL, split_type);
> >>
> >>      /*
> >>       * Unfreeze the post-split folios and put them back to the right
> >> @@ -4053,8 +4053,8 @@ static int __folio_freeze_split_unmapped_file(struct folio *folio, unsigned int
> >>      if (do_lru)
> >>              lruvec = folio_lruvec_lock(folio);
> >>
> >> -    ret = __split_unmapped_folio(folio, new_order, split_at, xas,
> >> -                                 mapping, split_type);
> >> +    ret = __split_frozen_folio(folio, new_order, split_at, xas,
> >> +                               mapping, split_type);
> >>
> >>      /*
> >>       * Unfreeze after-split folios and put them back to the right
> >
> > But now you have *unmapped_anon/file() call *frozen_folio().
> >
> > Given that you introduced *unmapped_anon/file() in the previous patch,
> > why not give them the right names from the start?
> >
>
> +1
>
> And just for completeness:  we cannot possibly freeze a mapped folio. So frozen
> implies unmapped.
>
> So the function can possibly just be called
>
>         __folio_freeze_split_file
>
> And we can can add a
>
>         VM_WARN_ON_ONCE(folio_mapped(folio));
>
> to self-document the expectation in the code.
>

Right, I'll just squash this into the previous commit then?