Re: [PATCH v3] mm: migrate: requeue destination folio on deferred split queue

[Andrew Morton]

On Thu, 12 Mar 2026 17:16:30 -0700 SeongJae Park <sj@xxxxxxxxxx> wrote:

> > By the time migrate_folio_move() runs, partially mapped folios without a
> > pin have already been split by migrate_pages_batch().  So only two cases
> > remain on the deferred list at this point:
> >   1. Partially mapped folios with a pin (split failed).
> >   2. Fully mapped but potentially underused folios.
> > The recorded partially_mapped state is forwarded to deferred_split_folio()
> > so that the destination folio is correctly re-queued in both cases.
> > 
> > Reported-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> > Fixes: dafff3f4c850 ("mm: split underused THPs")
> 
> Seems the commit is merged in 6.12.  And I assume the user impact on
> THP-shrinker enabled systems is visible.  If so, should we Cc stable@ ?

I think the user impact should be visible to backport, but the
changelog is elusive on details?