memory hotplug: make pages from movable zone always isolatable

Pages on movable zone have two types, MIGRATE_MOVABLE and MIGRATE_RESERVE,
both them can be movable, because only movable memory allocation can get
pages from movable zone.  This makes pages in movable zone always be able
to migrate.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Yakui Zhao <yakui.zhao@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8a8302711725..7b4d4e4ea64f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4906,13 +4906,16 @@ int set_migratetype_isolate(struct page *page)
         struct zone *zone;
         unsigned long flags;
         int ret = -EBUSY;
+        int zone_idx;
 
         zone = page_zone(page);
+        zone_idx = zone_idx(zone);
         spin_lock_irqsave(&zone->lock, flags);
         /*
          * In future, more migrate types will be able to be isolation target.
          */
-        if (get_pageblock_migratetype(page) != MIGRATE_MOVABLE)
+        if (get_pageblock_migratetype(page) != MIGRATE_MOVABLE &&
+            zone_idx != ZONE_MOVABLE)
                 goto out;
         set_pageblock_migratetype(page, MIGRATE_ISOLATE);
         move_freepages_block(zone, page, MIGRATE_ISOLATE);