[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, 3 insertions, 3 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 61d380678030..094455bcbbf7 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -286,7 +286,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
                         entry = *src_pte;
                         ptepage = pte_page(entry);
                         get_page(ptepage);
-                        add_mm_counter(dst, rss, HPAGE_SIZE / PAGE_SIZE);
+                        add_mm_counter(dst, file_rss, HPAGE_SIZE / PAGE_SIZE);
                         set_huge_pte_at(dst, addr, dst_pte, entry);
                 }
                 spin_unlock(&src->page_table_lock);
@@ -324,7 +324,7 @@ void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
 
                 page = pte_page(pte);
                 put_page(page);
-                add_mm_counter(mm, rss,  - (HPAGE_SIZE / PAGE_SIZE));
+                add_mm_counter(mm, file_rss, (int) -(HPAGE_SIZE / PAGE_SIZE));
         }
         flush_tlb_range(vma, start, end);
 }
@@ -386,7 +386,7 @@ int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
                                 goto out;
                         }
                 }
-                add_mm_counter(mm, rss, HPAGE_SIZE / PAGE_SIZE);
+                add_mm_counter(mm, file_rss, HPAGE_SIZE / PAGE_SIZE);
                 set_huge_pte_at(mm, addr, pte, make_huge_pte(vma, page));
         }
 out: