From 1ac0cb5d0e22d5e483f56b2bc12172dec1cf7536 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Mon, 21 Sep 2009 17:03:29 -0700 Subject: [PATCH] mm: fix anonymous dirtying 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 Cc: Acked-by: Rik van Riel Cc: KAMEZAWA Hiroyuki Cc: KOSAKI Motohiro Cc: Nick Piggin Cc: Mel Gorman Cc: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/memory.c b/mm/memory.c index 6359a4f80c4a..fc38d4ed9ad9 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2653,7 +2653,8 @@ 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)) -- 2.30.2