[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, 2 insertions, 2 deletions

diff --git a/mm/fremap.c b/mm/fremap.c
index ab23a0673c35..fd7f2a17ff3e 100644
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -39,7 +39,7 @@ static inline void zap_pte(struct mm_struct *mm, struct vm_area_struct *vma,
                                         set_page_dirty(page);
                                 page_remove_rmap(page);
                                 page_cache_release(page);
-                                dec_mm_counter(mm, rss);
+                                dec_mm_counter(mm, file_rss);
                         }
                 }
         } else {
@@ -95,7 +95,7 @@ int install_page(struct mm_struct *mm, struct vm_area_struct *vma,
 
         zap_pte(mm, vma, addr, pte);
 
-        inc_mm_counter(mm,rss);
+        inc_mm_counter(mm, file_rss);
         flush_icache_page(vma, page);
         set_pte_at(mm, addr, pte, mk_pte(page, prot));
         page_add_file_rmap(page);