On Fri, 25 Jun 2010, KOSAKI Motohiro wrote: > 'slab_reclaimable' and 'nr_pages' are unsigned. so, subtraction is > unsafe. Why? We are subtracting the current value of NR_SLAB_RECLAIMABLE from the earlier one. The result can be negative (maybe concurrent allocations) and then the nr_reclaimed gets decremented instead. This is okay since we have not reached our goal then of reducing the number of reclaimable slab pages on the zone. > @@ -2622,17 +2624,21 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) > * Note that shrink_slab will free memory on all zones and may > * take a long time. > */ > - while (shrink_slab(sc.nr_scanned, gfp_mask, lru_pages) && > - zone_page_state(zone, NR_SLAB_RECLAIMABLE) > > - slab_reclaimable - nr_pages) The comparison could be a problem here. So zone_page_state(zone, NR_SLAB_RECLAIMABLE) + nr_pages > slab_reclaimable ? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>