Re: [PATCH v3 03/18] mm/memcg: Use the node id in mem_cgroup_update_tree()

[Michal Hocko <mhocko@suse.com>]

On Wed 30-06-21 05:00:19, Matthew Wilcox wrote:
> By using the node id in mem_cgroup_update_tree(), we can delete
> soft_limit_tree_from_page() and mem_cgroup_page_nodeinfo().  Saves 42
> bytes of kernel text on my config.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Acked-by: Michal Hocko <mhocko@suse.com>

Thanks!

> ---
>  mm/memcontrol.c | 24 ++++--------------------
>  1 file changed, 4 insertions(+), 20 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 25cad0fb7d4e..29b28a050707 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -446,28 +446,12 @@ ino_t page_cgroup_ino(struct page *page)
>  	return ino;
>  }
>  
> -static struct mem_cgroup_per_node *
> -mem_cgroup_page_nodeinfo(struct mem_cgroup *memcg, struct page *page)
> -{
> -	int nid = page_to_nid(page);
> -
> -	return memcg->nodeinfo[nid];
> -}
> -
>  static struct mem_cgroup_tree_per_node *
>  soft_limit_tree_node(int nid)
>  {
>  	return soft_limit_tree.rb_tree_per_node[nid];
>  }
>  
> -static struct mem_cgroup_tree_per_node *
> -soft_limit_tree_from_page(struct page *page)
> -{
> -	int nid = page_to_nid(page);
> -
> -	return soft_limit_tree.rb_tree_per_node[nid];
> -}
> -
>  static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz,
>  					 struct mem_cgroup_tree_per_node *mctz,
>  					 unsigned long new_usage_in_excess)
> @@ -538,13 +522,13 @@ static unsigned long soft_limit_excess(struct mem_cgroup *memcg)
>  	return excess;
>  }
>  
> -static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
> +static void mem_cgroup_update_tree(struct mem_cgroup *memcg, int nid)
>  {
>  	unsigned long excess;
>  	struct mem_cgroup_per_node *mz;
>  	struct mem_cgroup_tree_per_node *mctz;
>  
> -	mctz = soft_limit_tree_from_page(page);
> +	mctz = soft_limit_tree_node(nid);
>  	if (!mctz)
>  		return;
>  	/*
> @@ -552,7 +536,7 @@ static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
>  	 * because their event counter is not touched.
>  	 */
>  	for (; memcg; memcg = parent_mem_cgroup(memcg)) {
> -		mz = mem_cgroup_page_nodeinfo(memcg, page);
> +		mz = memcg->nodeinfo[nid];
>  		excess = soft_limit_excess(memcg);
>  		/*
>  		 * We have to update the tree if mz is on RB-tree or
> @@ -879,7 +863,7 @@ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
>  						MEM_CGROUP_TARGET_SOFTLIMIT);
>  		mem_cgroup_threshold(memcg);
>  		if (unlikely(do_softlimit))
> -			mem_cgroup_update_tree(memcg, page);
> +			mem_cgroup_update_tree(memcg, page_to_nid(page));
>  	}
>  }
>  
> -- 
> 2.30.2

-- 
Michal Hocko
SUSE Labs