Commit 4b20477f authored Oct 26, 2010 by KAMEZAWA Hiroyuki Committed by Linus Torvalds Oct 26, 2010

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>

parent cf608ac1

mm/page_alloc.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -5336,7 +5336,7 @@ int set_migratetype_isolate(struct page *page)
		*/
		notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg);
		notifier_ret = notifier_to_errno(notifier_ret);
		if (notifier_ret \|\| !arg.pages_found)
		if (notifier_ret)
		goto out;

		for (iter = pfn; iter < (pfn + pageblock_nr_pages); iter++) {

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