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From: Yang Shi <shy828301@gmail.com>
Date: Fri, 26 Apr 2024 11:41:42 -0700
Message-ID: <CAHbLzkqZmd=HGQ8_adjEipp49GEzN45bz=NwJPi9X+qOHnNFZQ@mail.gmail.com>
Subject: Re: [PATCH v4] mm/rmap: do not add fully unmapped large folio to
 deferred split list
To: David Hildenbrand <david@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>, Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org, 
	"Matthew Wilcox (Oracle)" <willy@infradead.org>, Ryan Roberts <ryan.roberts@arm.com>, 
	Barry Song <21cnbao@gmail.com>, Lance Yang <ioworker0@gmail.com>, linux-kernel@vger.kernel.org
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On Fri, Apr 26, 2024 at 1:26=E2=80=AFAM David Hildenbrand <david@redhat.com=
> wrote:
>
>
> > @@ -1553,9 +1557,9 @@ static __always_inline void __folio_remove_rmap(s=
truct folio *folio,
> >                    * page of the folio is unmapped and at least one pag=
e
> >                    * is still mapped.
> >                    */
> > -               if (folio_test_large(folio) && folio_test_anon(folio))
> > -                       if (level =3D=3D RMAP_LEVEL_PTE || nr < nr_pmdm=
apped)
> > -                               deferred_split_folio(folio);
> > +               if (folio_test_large(folio) && folio_test_anon(folio) &=
&
> > +                   list_empty(&folio->_deferred_list) && partially_map=
ped)
> > +                       deferred_split_folio(folio);
>
> And now I realize that we can then even drop the folio_test_large(folio)
> check here!

Good idea. This is more understandable.

>
> --
> Cheers,
>
> David / dhildenb
>