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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 08:28:07 -0700
commit5d6ac1a7861f806ee68810a08a7064fec15477ed (patch)
tree3bf9fddbca35aa7b99ab87de4d48e8b039dad7a7
parent30f5582a68a013f742657c3f2b8737f0c5ad6c79 (diff)
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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 4126dd16778c..445ff3019c5b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2586,7 +2586,8 @@ 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))