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authorRik van Riel <riel@redhat.com>2010-03-05 13:42:09 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2010-03-06 11:26:26 -0800
commitc44b674323f4a2480dbeb65d4b487fa5f06f49e0 (patch)
treeb753050e6752eb2fc961ad3ea5dfdf88ef88364d /include/linux
parent033a64b56aed798991de18d226085dfb1ccd858d (diff)
rmap: move exclusively owned pages to own anon_vma in do_wp_page()
When the parent process breaks the COW on a page, both the original which is mapped at child and the new page which is mapped parent end up in that same anon_vma. Generally this won't be a problem, but for some workloads it could preserve the O(N) rmap scanning complexity. A simple fix is to ensure that, when a page which is mapped child gets reused in do_wp_page, because we already are the exclusive owner, the page gets moved to our own exclusive child's anon_vma. Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/rmap.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 62da2001d55c..72be23b1480a 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -125,6 +125,7 @@ static inline void anon_vma_merge(struct vm_area_struct *vma,
/*
* rmap interfaces called when adding or removing pte of page
*/
+void page_move_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
void page_add_file_rmap(struct page *);

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