I tried to start compaction via /proc/sys/vm/compact_memory as soon as I turned on my ARM-based platform. But the compaction didn't start. I found some variables in struct zone are not initalized. I think zone->compact_cached_free_pfn and some cache values for compaction are initalized when the kernel starts compaction, not via /proc/sys/vm/compact_memory. If my guess is correct, an initialization are needed for that case. Signed-off-by: Gioh Kim <gioh.kim@xxxxxxx> --- mm/compaction.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/mm/compaction.c b/mm/compaction.c index 8c0d945..944a9cc 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1299,6 +1299,14 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) __reset_isolation_suitable(zone); /* + * If this is activated by /proc/sys/vm/compact_memory + * and the first try, cached information for compaction is not + * initialized. + */ + if (cc->order == -1 && zone->compact_cached_free_pfn == 0) + __reset_isolation_suitable(zone); + + /* * Setup to move all movable pages to the end of the zone. Used cached * information on where the scanners should start but check that it * is initialised by ensuring the values are within zone boundaries. -- 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>