When the compaction is activated via /proc/sys/vm/compact_memory it would better scan the whole zone. And some platform, for instance ARM, has the start_pfn of a zone is zero. Therefore the first try to compaction via /proc doesn't work. It needs to force to reset compaction scanner position at first. Signed-off-by: Gioh Kim <gioh.kim@xxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Acked-by: David Rientjes <rientjes@xxxxxxxxxx> --- mm/compaction.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/mm/compaction.c b/mm/compaction.c index 8c0d945..ccf48ce 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1587,6 +1587,14 @@ static void __compact_pgdat(pg_data_t *pgdat, struct compact_control *cc) INIT_LIST_HEAD(&cc->freepages); INIT_LIST_HEAD(&cc->migratepages); + /* + * When called via /proc/sys/vm/compact_memory + * this makes sure we compact the whole zone regardless of + * cached scanner positions. + */ + if (cc->order == -1) + __reset_isolation_suitable(zone); + if (cc->order == -1 || !compaction_deferred(zone, cc->order)) compact_zone(zone, cc); -- 1.7.9.5 -- 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>