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authorHugh Dickins <hugh.dickins@tiscali.co.uk>2009-09-21 17:03:29 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2009-10-05 08:11:50 -0700
commit007a89a7e629137845da320c48af2a06c2bc624e (patch)
treebe1055eb99e37be7d3b9a45d0898b6d2d2be0739
parent66ff90a1b5fce45397f7643a11c33e1e92bd891e (diff)
mm: fix anonymous dirtying
commit 1ac0cb5d0e22d5e483f56b2bc12172dec1cf7536 upstream. do_anonymous_page() has been wrong to dirty the pte regardless. If it's not going to mark the pte writable, then it won't help to mark it dirty here, and clogs up memory with pages which will need swap instead of being thrown away. Especially wrong if no overcommit is chosen, and this vma is not yet VM_ACCOUNTed - we could exceed the limit and OOM despite no overcommit. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Acked-by: Rik van Riel <riel@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--mm/memory.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 3856c3681fc..1300b70f375 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2422,7 +2422,8 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
goto oom_free_page;
entry = mk_pte(page, vma->vm_page_prot);
- entry = maybe_mkwrite(pte_mkdirty(entry), vma);
+ if (vma->vm_flags & VM_WRITE)
+ entry = pte_mkwrite(pte_mkdirty(entry));
page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
if (!pte_none(*page_table))