linux-kernel - Re: [PATCH v4] mm/rmap: do not add fully unmapped large folio to deferred split list

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Date: Fri, 26 Apr 2024 10:26:03 +0200
From: David Hildenbrand <david@...hat.com>
To: Zi Yan <ziy@...dia.com>, Andrew Morton <akpm@...ux-foundation.org>,
 linux-mm@...ck.org
Cc: "Matthew Wilcox (Oracle)" <willy@...radead.org>,
 Yang Shi <shy828301@...il.com>, Ryan Roberts <ryan.roberts@....com>,
 Barry Song <21cnbao@...il.com>, Lance Yang <ioworker0@...il.com>,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4] mm/rmap: do not add fully unmapped large folio to
 deferred split list


> @@ -1553,9 +1557,9 @@ static __always_inline void __folio_remove_rmap(struct folio *folio,
>                    * page of the folio is unmapped and at least one page
>                    * is still mapped.
>                    */
> -               if (folio_test_large(folio) && folio_test_anon(folio))
> -                       if (level == RMAP_LEVEL_PTE || nr < nr_pmdmapped)
> -                               deferred_split_folio(folio);
> +               if (folio_test_large(folio) && folio_test_anon(folio) &&
> +                   list_empty(&folio->_deferred_list) && partially_mapped)
> +                       deferred_split_folio(folio);

And now I realize that we can then even drop the folio_test_large(folio) 
check here!

-- 
Cheers,

David / dhildenb