mm: Add notifier in pageblock isolation for balloon drivers

Memory balloon drivers can allocate a large amount of memory which is not
movable but could be freed to accomodate memory hotplug remove.

Prior to calling the memory hotplug notifier chain the memory in the
pageblock is isolated.  Currently, if the migrate type is not
MIGRATE_MOVABLE the isolation will not proceed, causing the memory removal
for that page range to fail.

Rather than failing pageblock isolation if the migrateteype is not
MIGRATE_MOVABLE, this patch checks if all of the pages in the pageblock,
and not on the LRU, are owned by a registered balloon driver (or other
entity) using a notifier chain.  If all of the non-movable pages are owned
by a balloon, they can be freed later through the memory notifier chain
and the range can still be isolated in set_migratetype_isolate().

Signed-off-by: Robert Jennings <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Brian King <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Gerald Schaefer <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Benjamin Herrenschmidt <[email protected]>

0 files changed, 0 insertions, 0 deletions