Re: [PATCH 3/7] mm/migrate: copy the referenced state via folio_migrate_refs()

[Kairui Song <ryncsn@gmail.com>]

On Thu, Aug 20, 2026 at 08:20:34PM +0800, David Hildenbrand (Arm) wrote:
> On 8/18/26 07:38, Kairui Song via B4 Relay wrote:
> > From: Kairui Song <kasong@tencent.com>
> > 
> > folio_migrate_flags() copies PG_referenced separately, while
> > folio_migrate_refs() copies the rest of the reference state. Make
> > folio_migrate_refs() copy the complete state, i.e., PG_referenced plus
> > the MGLRU refs counter, in both LRU implementations, and drop the
> > open-coded copy so the reference state is transferred in one place.
> > 
> > Signed-off-by: Kairui Song <kasong@tencent.com>
> > ---
> >  include/linux/mm_inline.h | 16 +++++++++++++---
> >  mm/migrate.c              |  4 ++--
> >  2 files changed, 15 insertions(+), 5 deletions(-)
> > 
> > diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
> > index 93bf3fa221f8..df62daaa2ee7 100644
> > --- a/include/linux/mm_inline.h
> > +++ b/include/linux/mm_inline.h
> > @@ -366,11 +366,19 @@ static inline bool lru_gen_del_folio(struct lruvec *lruvec, struct folio *folio,
> >  	return true;
> >  }
> >  
> > +/**
> > + * folio_migrate_refs - copy the reference state to a new folio
> > + * @new: the destination folio
> > + * @old: the source folio
> > + *
> 
> Man, that function has a confusing name (refs vs. ref_count). :)
> 
> "ref_state" would be clearer (just what the description says).
> 
> Or better, "folio_migrate_lru_refs", because that's literally the name of the
> function you use: folio_set_lru_refs.
> 
> Can we have a cleanup patch to name that consistently?

Sure, I think I can just rename it here as the code gets consolidated
and kdoc being added