[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/mm/rmap.c b/mm/rmap.c
index 1fc559e..5047576 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -445,8 +445,6 @@
{
BUG_ON(PageReserved(page));
- inc_mm_counter(vma->vm_mm, anon_rss);
-
if (atomic_inc_and_test(&page->_mapcount)) {
struct anon_vma *anon_vma = vma->anon_vma;
@@ -561,9 +559,9 @@
set_pte_at(mm, address, pte, swp_entry_to_pte(entry));
BUG_ON(pte_file(*pte));
dec_mm_counter(mm, anon_rss);
- }
+ } else
+ dec_mm_counter(mm, file_rss);
- dec_mm_counter(mm, rss);
page_remove_rmap(page);
page_cache_release(page);
@@ -667,7 +665,7 @@
page_remove_rmap(page);
page_cache_release(page);
- dec_mm_counter(mm, rss);
+ dec_mm_counter(mm, file_rss);
(*mapcount)--;
}