Re: [PATCH] mm: Fix vmstat after removing NR_BOUNCE

[Michal Hocko <mhocko@suse.com>]

On Thu 29-05-25 13:38:32, Kirill A. Shutemov wrote:
> Hongyu noticed that the nr_unaccepted counter kept growing even in the
> absence of unaccepted memory on the machine.
> 
> This happens due to a commit that removed NR_BOUNCE: it removed the
> counter from the enum zone_stat_item, but left it in the vmstat_text
> array.
> 
> As a result, all counters below nr_bounce in /proc/vmstat are
> shifted by one line, causing the numa_hit counter to be labeled as
> nr_unaccepted.
> 
> To fix this issue, remove nr_bounce from the vmstat_text array.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Reported-by: Hongyu Ning <hongyu.ning@linux.intel.com>
> Fixes: 194df9f66db8 ("mm: remove NR_BOUNCE zone stat")
> Cc: stable@vger.kernel.org
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Hannes Reinecke <hare@suse.de>
> Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> Cc: Jens Axboe <axboe@kernel.dk>

Acked-by: Michal Hocko <mhocko@suse.com>
Unfortunatelly a common mistake to make. I have seen you have a followup
fix with a stricter build time check. Will have a look.

Thanks!

> ---
>  mm/vmstat.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/mm/vmstat.c b/mm/vmstat.c
> index 4c268ce39ff2..ae9882063d89 100644
> --- a/mm/vmstat.c
> +++ b/mm/vmstat.c
> @@ -1201,7 +1201,6 @@ const char * const vmstat_text[] = {
>  	"nr_zone_unevictable",
>  	"nr_zone_write_pending",
>  	"nr_mlock",
> -	"nr_bounce",
>  #if IS_ENABLED(CONFIG_ZSMALLOC)
>  	"nr_zspages",
>  #endif
> -- 
> 2.47.2

-- 
Michal Hocko
SUSE Labs