Merge branch 'linux-2.6' into for-2.6.22

1 files changed, 25 insertions, 21 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index b6491c020f26..f92ba2a869b4 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -532,6 +532,12 @@ static void cfq_add_rq_rb(struct request *rq)
 
 	if (!cfq_cfqq_on_rr(cfqq))
 		cfq_add_cfqq_rr(cfqd, cfqq);
+
+	/*
+	 * check if this request is a better next-serve candidate
+	 */
+	cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
+	BUG_ON(!cfqq->next_rq);
 }
 
 static inline void
@@ -986,9 +992,9 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	 * expire an async queue immediately if it has used up its slice. idle
 	 * queue always expire after 1 dispatch round.
 	 */
-	if ((!cfq_cfqq_sync(cfqq) &&
+	if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) &&
 	    cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
-	    cfq_class_idle(cfqq)) {
+	    cfq_class_idle(cfqq))) {
 		cfqq->slice_end = jiffies + 1;
 		cfq_slice_expired(cfqd, 0, 0);
 	}
@@ -1051,19 +1057,21 @@ cfq_dispatch_requests(request_queue_t *q, int force)
 	while ((cfqq = cfq_select_queue(cfqd)) != NULL) {
 		int max_dispatch;
 
-		/*
-		 * Don't repeat dispatch from the previous queue.
-		 */
-		if (prev_cfqq == cfqq)
-			break;
+		if (cfqd->busy_queues > 1) {
+			/*
+			 * Don't repeat dispatch from the previous queue.
+			 */
+			if (prev_cfqq == cfqq)
+				break;
 
-		/*
-		 * So we have dispatched before in this round, if the
-		 * next queue has idling enabled (must be sync), don't
-		 * allow it service until the previous have continued.
-		 */
-		if (cfqd->rq_in_driver && cfq_cfqq_idle_window(cfqq))
-			break;
+			/*
+			 * So we have dispatched before in this round, if the
+			 * next queue has idling enabled (must be sync), don't
+			 * allow it service until the previous have continued.
+			 */
+			if (cfqd->rq_in_driver && cfq_cfqq_idle_window(cfqq))
+				break;
+		}
 
 		cfq_clear_cfqq_must_dispatch(cfqq);
 		cfq_clear_cfqq_wait_request(cfqq);
@@ -1370,7 +1378,9 @@ retry:
 		atomic_set(&cfqq->ref, 0);
 		cfqq->cfqd = cfqd;
 
-		cfq_mark_cfqq_idle_window(cfqq);
+		if (key != CFQ_KEY_ASYNC)
+			cfq_mark_cfqq_idle_window(cfqq);
+
 		cfq_mark_cfqq_prio_changed(cfqq);
 		cfq_mark_cfqq_queue_new(cfqq);
 		cfq_init_prio_data(cfqq);
@@ -1635,12 +1645,6 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 		cfqq->meta_pending++;
 
 	/*
-	 * check if this request is a better next-serve candidate)) {
-	 */
-	cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
-	BUG_ON(!cfqq->next_rq);
-
-	/*
 	 * we never wait for an async request and we don't allow preemption
 	 * of an async request. so just return early
 	 */