+ mm-balloon_compaction-keep-ballooned-pages-away-from-normal-migration-path.patch added to -mm tree

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The patch titled
     Subject: mm/balloon_compaction: keep ballooned pages away from normal migration path
has been added to the -mm tree.  Its filename is
     mm-balloon_compaction-keep-ballooned-pages-away-from-normal-migration-path.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/mm-balloon_compaction-keep-ballooned-pages-away-from-normal-migration-path.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/mm-balloon_compaction-keep-ballooned-pages-away-from-normal-migration-path.patch

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------------------------------------------------------
From: Konstantin Khlebnikov <k.khlebnikov@xxxxxxxxxxx>
Subject: mm/balloon_compaction: keep ballooned pages away from normal migration path

Proper testing shows yet another problem in balloon migration: it works
only once for each page.  balloon_page_movable() check page flags and
page_count.  In __unmap_and_move page is locked, reference counter is
elevated, so balloon_page_movable() _always_ fails here.  As result in
__unmap_and_move() migration goes to the normal migration path.

Balloon ->migratepage() is so special, it returns
MIGRATEPAGE_BALLOON_SUCCESS instead of MIGRATEPAGE_SUCCESS.  After that in
move_to_new_page() successfully migrated page got NULL into its mapping
pointer and loses connectivity with balloon and ability for further
migration.

It's safe to use __is_movable_balloon_page here: page is isolated and pinned.

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@xxxxxxxxxxx>
Acked-by: Rafael Aquini <aquini@xxxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>	[v3.8+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/migrate.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -puN mm/migrate.c~mm-balloon_compaction-keep-ballooned-pages-away-from-normal-migration-path mm/migrate.c
--- a/mm/migrate.c~mm-balloon_compaction-keep-ballooned-pages-away-from-normal-migration-path
+++ a/mm/migrate.c
@@ -873,7 +873,7 @@ static int __unmap_and_move(struct page
 		}
 	}
 
-	if (unlikely(balloon_page_movable(page))) {
+	if (unlikely(__is_movable_balloon_page(page))) {
 		/*
 		 * A ballooned page does not need any special attention from
 		 * physical to virtual reverse mapping procedures.
_

Patches currently in -mm which might be from k.khlebnikov@xxxxxxxxxxx are

mm-balloon_compaction-ignore-anonymous-pages.patch
mm-balloon_compaction-keep-ballooned-pages-away-from-normal-migration-path.patch
mm-balloon_compaction-isolate-balloon-pages-without-lru_lock.patch
mm-introduce-common-page-state-for-ballooned-memory.patch
mm-balloon_compaction-use-common-page-ballooning.patch
mm-balloon_compaction-general-cleanup.patch

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