Re: [PATCH v2 12/46] mm/memcg: Use the node id in mem_cgroup_update_tree()

[Christoph Hellwig]

On Tue, Jun 22, 2021 at 01:15:17PM +0100, Matthew Wilcox (Oracle) wrote:
>  static struct mem_cgroup_per_node *
> -mem_cgroup_page_nodeinfo(struct mem_cgroup *memcg, struct page *page)
> +mem_cgroup_nodeinfo(struct mem_cgroup *memcg, int nid)
>  {
> -	int nid = page_to_nid(page);
> -
>  	return memcg->nodeinfo[nid];
>  }

I'd just kill this function entirely and open code it into the only
caller

> -	mctz = soft_limit_tree_from_page(page);
> +	mctz = soft_limit_tree_node(nid);

And while were at it, soft_limit_tree_node seems like a completely
pointless helper that does nothing but obsfucating the code.  While
you touch this area it might be worth to spin another patch to just
remove it as well.