mm/balloon_compaction.c: enqueue zero page to balloon device

presently pages in the balloon device have random value, and these pages
will be scanned by ksmd on the host.  They usually cannot be merged.
Enqueue zero pages will resolve this problem.

Link: http://lkml.kernel.org/r/1498698637-26389-1-git-send-email-zhenwei.pi@youruncloud.com
Signed-off-by: zhenwei.pi <zhenwei.pi@youruncloud.com>
Cc: Gioh Kim <gi-oh.kim@profitbricks.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index da91df50ba31abfbe742afd9611682d5740a9afb..9075aa54e95517cdbb1094f04e72c36357401e52 100644 (file)
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -24,7 +24,7 @@ struct page *balloon_page_enqueue(struct balloon_dev_info *b_dev_info)
 {
        unsigned long flags;
        struct page *page = alloc_page(balloon_mapping_gfp_mask() |
-                                       __GFP_NOMEMALLOC | __GFP_NORETRY);
+                               __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_ZERO);
        if (!page)
                return NULL;