[PATCH] fix the kswapd zone scanning algorithm

This removes a vestige of the old algorithm.  We don't want to skip zones if
all_zones_ok is true: we've already precalculated which zones need scanning
and this just stops us from ever performing kswapd reclaim from the DMA zone.

mm/vmscan.c

@@ -970,8 +970,6 @@ static int balance_pgdat(pg_data_t *pgdat, int nr_pages, struct page_state *ps)
 			if (nr_pages == 0) {	/* Not software suspend */
 				if (zone->free_pages <= zone->pages_high)
 					all_zones_ok = 0;
-				if (all_zones_ok)
-					continue;
 			}
 			zone->temp_priority = priority;
 			max_scan = zone->nr_inactive >> priority;