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authorMinchan Kim <minchan@kernel.org>2012-10-08 16:32:16 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-09 16:22:46 +0900
commit435b405c06119d93333738172b8060b0ed12af41 (patch)
treea87f9a493f5c677ab23eeab1eab2e45caeb79bc3 /mm/page_alloc.c
parent41d575ad4a511b71a4a41c8313004212f5c229b1 (diff)
downloadlinux-435b405c06119d93333738172b8060b0ed12af41.tar.bz2
memory-hotplug: fix pages missed by race rather than failing
If race between allocation and isolation in memory-hotplug offline happens, some pages could be in MIGRATE_MOVABLE of free_list although the pageblock's migratetype of the page is MIGRATE_ISOLATE. The race could be detected by get_freepage_migratetype in __test_page_isolated_in_pageblock. If it is detected, now EBUSY gets bubbled all the way up and the hotplug operations fails. But better idea is instead of returning and failing memory-hotremove, move the free page to the correct list at the time it is detected. It could enhance memory-hotremove operation success ratio although the race is really rare. Suggested by Mel Gorman. [akpm@linux-foundation.org: small cleanup] Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 94fd283dde98..82f0b2f54f81 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -925,7 +925,7 @@ static int fallbacks[MIGRATE_TYPES][4] = {
* Note that start_page and end_pages are not aligned on a pageblock
* boundary. If alignment is required, use move_freepages_block()
*/
-static int move_freepages(struct zone *zone,
+int move_freepages(struct zone *zone,
struct page *start_page, struct page *end_page,
int migratetype)
{