Subject: + page-owners-correct-page-order-when-to-free-page.patch added to -mm tree
To: jungsoo.son@xxxxxxx,iamjoonsoo.kim@xxxxxxx,minchan@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Wed, 12 Mar 2014 13:03:50 -0700
The patch titled
Subject: page owners: correct page->order when to free page
has been added to the -mm tree. Its filename is
page-owners-correct-page-order-when-to-free-page.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/page-owners-correct-page-order-when-to-free-page.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/page-owners-correct-page-order-when-to-free-page.patch
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From: Jungsoo Son <jungsoo.son@xxxxxxx>
Subject: page owners: correct page->order when to free page
When I use PAGE_OWNER in mmotm tree, I found a problem that mismatches the
number of allocated pages. When I investigate, the problem is that
set_page_order is called for only a head page if freed page is merged to a
higher order page in the buddy allocator so tail pages of the higher order
page couldn't be reset to page->order = -1.
It means when we do 'cat /proc/page-owner', it could show wrong
information.
So page->order should be set to -1 for all the tail pages as well as the
first page before buddy allocator merges them.
This patch is for clearing page->order of all the tail pages in
free_pages_prepare() when to free page.
Signed-off-by: Jungsoo Son <jungsoo.son@xxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Acked-by: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 7 +++++++
1 file changed, 7 insertions(+)
diff -puN mm/page_alloc.c~page-owners-correct-page-order-when-to-free-page mm/page_alloc.c
--- a/mm/page_alloc.c~page-owners-correct-page-order-when-to-free-page
+++ a/mm/page_alloc.c
@@ -742,6 +742,13 @@ static bool free_pages_prepare(struct pa
if (bad)
return false;
+#ifdef CONFIG_PAGE_OWNER
+ for (i = 0; i < (1 << order); i++) {
+ struct page *p = (page + i);
+ p->order = -1;
+ }
+#endif
+
if (!PageHighMem(page)) {
debug_check_no_locks_freed(page_address(page),
PAGE_SIZE << order);
_
Patches currently in -mm which might be from jungsoo.son@xxxxxxx are
page-owners-correct-page-order-when-to-free-page.patch
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