[PATCH] mm: zap_pte_range dont dirty anon

zap_pte_range already avoids wasting time to mark_page_accessed on anon pages:
it can also skip anon set_page_dirty - the page only needs to be marked dirty
if shared with another mm, but that will say pte_dirty too.

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, 6 insertions, 4 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 222c13e46130..fd5d4c6dc762 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -574,12 +574,14 @@ static void zap_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
                                                 addr) != page->index)
                                 set_pte_at(tlb->mm, addr, pte,
                                            pgoff_to_pte(page->index));
-                        if (pte_dirty(ptent))
-                                set_page_dirty(page);
                         if (PageAnon(page))
                                 dec_mm_counter(tlb->mm, anon_rss);
-                        else if (pte_young(ptent))
-                                mark_page_accessed(page);
+                        else {
+                                if (pte_dirty(ptent))
+                                        set_page_dirty(page);
+                                if (pte_young(ptent))
+                                        mark_page_accessed(page);
+                        }
                         tlb->freed++;
                         page_remove_rmap(page);
                         tlb_remove_page(tlb, page);