memory hotplug: fix notifier's return value check
authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tue, 26 Oct 2010 21:21:29 +0000 (14:21 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 26 Oct 2010 23:52:06 +0000 (16:52 -0700)
commit4b20477f588055fbe87e69435d3c2344d250f0d7
tree4e4d1ef7280ea5c09ff10489e6b9c47bc1223a73
parentcf608ac19c95804dc2df43b1f4f9e068aa9034ab
memory hotplug: fix notifier's return value check

Even if notifier cannot find any pages, it doesn't mean no pages are
available...And, if there are no notifiers registered, this condition will
be always true and memory hotplug will show -EBUSY.

This is a bug but not critical.

In most case, a pageblock which will be offlined is MIGRATE_MOVABLE This
"notifier" is called only when the pageblock is _not_ MIGRATE_MOVABLE.
But if not MIGRATE_MOVABLE, it's common case that memory hotplug will
fail.  So, no one notice this bug.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/page_alloc.c