Re: [PATCH -v2 next 4/4] memcg: factor out stat(event)/stat_local(event_local) reading functions

[Roman Gushchin <roman.gushchin@linux.dev>]

On Tue, Jan 14, 2025 at 12:25:19PM +0000, Chen Ridong wrote:
> From: Chen Ridong <chenridong@huawei.com>
> 
> The only difference between 'lruvec_page_state' and
> 'lruvec_page_state_local' is that they read 'state' and 'state_local',
> respectively. Factor out an inner functions to make the code more concise.
> Do the same for reading 'memcg_page_stat' and 'memcg_events'.
> 
> Signed-off-by: Chen Ridong <chenridong@huawei.com>
> ---
>  mm/memcontrol.c | 72 +++++++++++++++++++++----------------------------
>  1 file changed, 30 insertions(+), 42 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index b10e0a8f3375..14541610cad0 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -375,7 +375,8 @@ struct lruvec_stats {
>  	long state_pending[NR_MEMCG_NODE_STAT_ITEMS];
>  };
>  
> -unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
> +static unsigned long __lruvec_page_state(struct lruvec *lruvec,
> +		enum node_stat_item idx, bool local)
>  {
>  	struct mem_cgroup_per_node *pn;
>  	long x;
> @@ -389,7 +390,8 @@ unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
>  		return 0;
>  
>  	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
> -	x = READ_ONCE(pn->lruvec_stats->state[i]);
> +	x = local ? READ_ONCE(pn->lruvec_stats->state_local[i]) :
> +		    READ_ONCE(pn->lruvec_stats->state[i]);
>  #ifdef CONFIG_SMP
>  	if (x < 0)
>  		x = 0;
> @@ -397,27 +399,16 @@ unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
>  	return x;
>  }
>  
> +
> +unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
> +{
> +	return __lruvec_page_state(lruvec, idx, false);
> +}

I'd move these wrapper function definitions to memcontrol.h and make them
static inline.

Other than that, lgtm.

Thank you!