From 435b405c06119d93333738172b8060b0ed12af41 Mon Sep 17 00:00:00 2001 From: Minchan Kim Date: Mon, 8 Oct 2012 16:32:16 -0700 Subject: 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 Cc: KAMEZAWA Hiroyuki Reviewed-by: Yasuaki Ishimatsu Acked-by: Mel Gorman Cc: Xishi Qiu Cc: Wen Congyang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/page-isolation.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/page-isolation.h') diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h index 105077aa7685..fca8c0a5c188 100644 --- a/include/linux/page-isolation.h +++ b/include/linux/page-isolation.h @@ -6,6 +6,10 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int count); void set_pageblock_migratetype(struct page *page, int migratetype); int move_freepages_block(struct zone *zone, struct page *page, int migratetype); +int move_freepages(struct zone *zone, + struct page *start_page, struct page *end_page, + int migratetype); + /* * Changes migrate type in [start_pfn, end_pfn) to be MIGRATE_ISOLATE. * If specified range includes migrate types other than MOVABLE or CMA, -- cgit v1.2.1