Re: [PATCH 7/9] memcg: remove the per-node soft limit tree fields

[Michal Hocko]

On Tue 11-08-26 13:32:01, Shakeel Butt wrote:
> tree_node, usage_in_excess and on_tree only existed for the soft limit
> rbtree. They also doubled as the buffer between the read-mostly head of
> struct mem_cgroup_per_node and its update-often tail, so replace them
> with the explicit padding that CONFIG_MEMCG_V1=n already used.
> 
> Signed-off-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>

Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Thanks!

> ---
>  include/linux/memcontrol.h | 13 -------------
>  1 file changed, 13 deletions(-)
> 
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 7b02f1b3bb88..ce24e04967d8 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -95,20 +95,7 @@ struct mem_cgroup_per_node {
>  	struct lruvec_stats			*lruvec_stats;
>  	struct shrinker_info __rcu	*shrinker_info;
>  
> -#ifdef CONFIG_MEMCG_V1
> -	/*
> -	 * Memcg-v1 only stuff in middle as buffer between read mostly fields
> -	 * and update often fields to avoid false sharing. If v1 stuff is
> -	 * not present, an explicit padding is needed.
> -	 */
> -
> -	struct rb_node		tree_node;	/* RB tree node */
> -	unsigned long		usage_in_excess;/* Set to the value by which */
> -						/* the soft limit is exceeded*/
> -	bool			on_tree;
> -#else
>  	CACHELINE_PADDING(_pad1_);
> -#endif
>  
>  	/* Fields which get updated often at the end. */
>  	struct lruvec		lruvec;
> -- 
> 2.53.0-Meta

-- 
Michal Hocko
SUSE Labs