There are a couple of issues with sync_mm_rss(), as added by patch:

	commit 34e55232e59f7b19050267a05ff1226e5cd122a5
	Author: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
	Date:   Fri Mar 5 13:41:40 2010 -0800
	Subject: mm: avoid false sharing of mm_counter

 (1) You haven't implemented it for NOMMU mode.  What's the right way to do
     this?  Just give an empty function?

 (2) linux/mm.h should carry the empty function as an inline when
     CONFIG_SPLIT_RSS_COUNTING=n, rather than it being defined as an empty
     function in mm/memory.c.

David