linux-kernel - Re: [PATCH] mm: migrate: drop redundant anonymous statistics for file folios migration

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Message-ID: <87v7vy7kos.fsf@DESKTOP-5N7EMDA>
Date: Thu, 05 Dec 2024 13:39:15 +0800
From: "Huang, Ying" <ying.huang@...ux.alibaba.com>
To: Baolin Wang <baolin.wang@...ux.alibaba.com>
Cc: akpm@...ux-foundation.org,  21cnbao@...il.com,  david@...hat.com,
  ziy@...dia.com,  linux-mm@...ck.org,  linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm: migrate: drop redundant anonymous statistics for
 file folios migration

Baolin Wang <baolin.wang@...ux.alibaba.com> writes:

> Commit 5d65c8d758f2 ("mm: count the number of anonymous THPs per size") adds
> a new anonymous counter per THP size, however, when folio_mapping() is not NULL
> during folio migration, it means this is not an anonymous folio, so remove the
> redundant anonymous statistics in this case.

They may be anonymous folios in swap cache?

> Signed-off-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
> ---
>  mm/migrate.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/mm/migrate.c b/mm/migrate.c
> index e9e00d1d1d19..d7fdfdd23fd0 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -523,8 +523,6 @@ static int __folio_migrate_mapping(struct address_space *mapping,
>  	 */
>  	newfolio->index = folio->index;
>  	newfolio->mapping = folio->mapping;
> -	if (folio_test_anon(folio) && folio_test_large(folio))
> -		mod_mthp_stat(folio_order(folio), MTHP_STAT_NR_ANON, 1);
>  	folio_ref_add(newfolio, nr); /* add cache reference */
>  	if (folio_test_swapbacked(folio)) {
>  		__folio_set_swapbacked(newfolio);

---
Best Regards,
Huang, Ying