Re: [PATCH 3/4] mm/vmstat: remove unused __node_stat_* wrappers

[Joshua Hahn]

On Tue, 14 Apr 2026 17:15:20 +0800 Ye Liu <ye.liu@xxxxxxxxx> wrote:

> From: Ye Liu <liuye@xxxxxxxxxx>
> 
> Replace the single call to __node_stat_mod_folio()
> with node_stat_mod_folio(), and remove the dead inline __node_stat_*
> wrapper definitions from include/linux/vmstat.h.
> 
> Signed-off-by: Ye Liu <liuye@xxxxxxxxxx>
> ---
>  include/linux/vmstat.h | 18 ------------------
>  mm/page-writeback.c    |  2 +-
>  2 files changed, 1 insertion(+), 19 deletions(-)
> 
> diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
> index 3c9c266cf782..54da7d820f78 100644
> --- a/include/linux/vmstat.h
> +++ b/include/linux/vmstat.h
> @@ -440,24 +440,6 @@ static inline void zone_stat_sub_folio(struct folio *folio,
>  	mod_zone_page_state(folio_zone(folio), item, -folio_nr_pages(folio));
>  }
>  
> -static inline void __node_stat_mod_folio(struct folio *folio,
> -		enum node_stat_item item, long nr)
> -{
> -	__mod_node_page_state(folio_pgdat(folio), item, nr);
> -}
> -
> -static inline void __node_stat_add_folio(struct folio *folio,
> -		enum node_stat_item item)
> -{
> -	__mod_node_page_state(folio_pgdat(folio), item, folio_nr_pages(folio));
> -}
> -
> -static inline void __node_stat_sub_folio(struct folio *folio,
> -		enum node_stat_item item)
> -{
> -	__mod_node_page_state(folio_pgdat(folio), item, -folio_nr_pages(folio));
> -}
> -
>  static inline void node_stat_mod_folio(struct folio *folio,
>  		enum node_stat_item item, long nr)
>  {
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index 6f9b7b081ab7..ed3301753e89 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -2627,7 +2627,7 @@ static void folio_account_dirtied(struct folio *folio,
>  
>  		lruvec_stat_mod_folio(folio, NR_FILE_DIRTY, nr);
>  		__zone_stat_mod_folio(folio, NR_ZONE_WRITE_PENDING, nr);
> -		__node_stat_mod_folio(folio, NR_DIRTIED, nr);
> +		node_stat_mod_folio(folio, NR_DIRTIED, nr);

Hi Ye, thank you for the patch,

In addition to what Matthew has pointed out, I also wanted to note that this
substitution isn't trivial; there are differences between the __ prefixed
version of node_stat_mod_folio and the one without. Even though the correctness
of the two versions might be the same, I think that a change like this should
be supplemented by a description of what side effects this change has
(i.e. introducing additional overhead from the cmpxchg loop).

Thank you, I hope you have a great day!
Joshua