[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>

1 files changed, 1 insertions, 1 deletions

diff --git a/mm/nommu.c b/mm/nommu.c
index 0ef241ae3763..599924886eb5 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1083,7 +1083,7 @@ void update_mem_hiwater(struct task_struct *tsk)
         unsigned long rss;
 
         if (likely(tsk->mm)) {
-                rss = get_mm_counter(tsk->mm, rss);
+                rss = get_mm_rss(tsk->mm);
                 if (tsk->mm->hiwater_rss < rss)
                         tsk->mm->hiwater_rss = rss;
                 if (tsk->mm->hiwater_vm < tsk->mm->total_vm)