Re: [PATCH] mm/vmstat: avoid taking zone lock in /proc/buddyinfo reads

[Lorenzo Stoakes <ljs@kernel.org>]

Hi Andrew,

I think this one got missed last cycle? I don't see it in any mm- tree, and has
a bunch of tags.

I guess Imran will need to resend it at -rc1?

Cheers, Lorenzo

On Thu, Jun 04, 2026 at 09:42:45PM +0800, Imran Khan wrote:
> frag_show_print() just reads zone->free_area[order].nr_free, so
> it can safely do this without needing the zone->lock.
>
> Pass nolock=true from frag_show(), so that walk_zones_in_node()
> can skip the zone->lock acquisition.
>
> Signed-off-by: Imran Khan <imran.f.khan@oracle.com>
> ---
>  mm/vmstat.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/vmstat.c b/mm/vmstat.c
> index f534972f517de..7b93fbf9af092 100644
> --- a/mm/vmstat.c
> +++ b/mm/vmstat.c
> @@ -1568,7 +1568,7 @@ static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
>  static int frag_show(struct seq_file *m, void *arg)
>  {
>  	pg_data_t *pgdat = (pg_data_t *)arg;
> -	walk_zones_in_node(m, pgdat, true, false, frag_show_print);
> +	walk_zones_in_node(m, pgdat, true, true, frag_show_print);
>  	return 0;
>  }
>
>
> base-commit: e43ffb69e0438cddd72aaa30898b4dc446f664f8
> --
> 2.34.1
>