[PATCH] mm: rss = file_rss + anon_rss

I was lazy when we added anon_rss, and chose to change as few places as
possible.  So currently each anonymous page has to be counted twice, in rss
and in anon_rss.  Which won't be so good if those are atomic counts in some
configurations.

Change that around: keep file_rss and anon_rss separately, and add them
together (with get_mm_rss macro) when the total is needed - reading two
atomics is much cheaper than updating two atomics.  And update anon_rss
upfront, typically in memory.c, not tucked away in page_add_anon_rmap.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/proc/array.c b/fs/proc/array.c
index d84eeca..3e1239e 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -438,7 +438,7 @@
 		jiffies_to_clock_t(it_real_value),
 		start_time,
 		vsize,
-		mm ? get_mm_counter(mm, rss) : 0, /* you might want to shift this left 3 */
+		mm ? get_mm_rss(mm) : 0,
 	        rsslim,
 		mm ? mm->start_code : 0,
 		mm ? mm->end_code : 0,