On Thu, Apr 03, 2014 at 05:40:18PM +0200, Vlastimil Babka wrote: > For the MIGRATE_RESERVE pages, it is important they do not get misplaced > on free_list of other migratetype, otherwise the whole MIGRATE_RESERVE > pageblock might be changed to other migratetype in try_to_steal_freepages(). > For MIGRATE_CMA, the pages also must not go to a different free_list, otherwise > they could get allocated as unmovable and result in CMA failure. > > This is ensured by setting the freepage_migratetype appropriately when placing > pages on pcp lists, and using the information when releasing them back to > free_list. It is also assumed that CMA and RESERVE pageblocks are created only > in the init phase. This patch adds DEBUG_VM checks to catch any regressions > introduced for this invariant. Hello, Vlastimil. Idea looks good to me. > > Cc: Yong-Taek Lee <ytk.lee@xxxxxxxxxxx> > Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx> > Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> > Cc: Mel Gorman <mgorman@xxxxxxx> > Cc: Minchan Kim <minchan@xxxxxxxxxx> > Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> > Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> > Cc: Hugh Dickins <hughd@xxxxxxxxxx> > Cc: Rik van Riel <riel@xxxxxxxxxx> > Cc: Michal Nazarewicz <mina86@xxxxxxxxxx> > Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx> Acked-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>