[PATCH] make deadline_merge prefetch next entry

Make deadline_merge() prefetch the next entry on the list.

drivers/block/deadline-iosched.c

@@ -118,6 +118,8 @@ deadline_find_hash(struct deadline_data *dd, sector_t offset)
 
 	while ((entry = next) != hash_list) {
 		next = entry->next;
+		prefetch(next);
+		
 		drq = list_entry_hash(entry);
 
 		BUG_ON(!drq->hash_valid_count);
@@ -191,6 +193,8 @@ deadline_merge(request_queue_t *q, struct list_head **insert, struct bio *bio)
 	while ((entry = entry->prev) != sort_list) {
 		__rq = list_entry_rq(entry);
 
+		prefetch(entry->prev);
+
 		BUG_ON(__rq->flags & REQ_STARTED);
 
 		if (!(__rq->flags & REQ_CMD))
@@ -298,6 +302,8 @@ static void deadline_move_requests(struct deadline_data *dd, struct request *rq)
 		struct list_head *nxt = rq->queuelist.next;
 		int this_rq_cost;
 
+		prefetch(nxt);
+
 		/*
 		 * take it off the sort and fifo list, move
 		 * to dispatch queue