Matthew Wilcox (Oracle) [off-list ref] 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>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: David Howells <dhowells@redhat.com>

Though I wonder if:

-		mz = mem_cgroup_page_nodeinfo(memcg, page);
+		mz = memcg->nodeinfo[nid];

should still have some sort of wrapper function.