From: Hugh Dickins <hugh@veritas.com>
Date: Sun, 30 Oct 2005 01:15:54 +0000 (-0700)
Subject: [PATCH] mm: zap_pte_range dont dirty anon
X-Git-Tag: v2.6.15-rc1~730^2^2~72
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6237bcd94851e9cf0ecd2520d744779df0f5a9a6;p=linux-2.6

[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>
---

diff --git a/mm/memory.c b/mm/memory.c
index 222c13e461..fd5d4c6dc7 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);