---

yaml
---
r: 172976
b: refs/heads/master
c: 8e55063
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 76280aff1c7e9ae761cac4b48591c43cd7d69159
+refs/heads/master: 8e550632cccae34e265cb066691945515eaa7fb5

trunk/block/cfq-iosched.c

@@ -172,6 +172,7 @@ struct cfq_data {
 	enum wl_prio_t serving_prio;
 	enum wl_type_t serving_type;
 	unsigned long workload_expires;
+	bool noidle_tree_requires_idle;
 
 	/*
 	 * Each priority tree is sorted by next_request position.  These
@@ -1253,9 +1254,9 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
 		return;
 
 	/*
-	 * still requests with the driver, don't idle
+	 * still active requests from this queue, don't idle
 	 */
-	if (rq_in_driver(cfqd))
+	if (cfqq->dispatched)
 		return;
 
 	/*
@@ -1478,6 +1479,7 @@ static void choose_service_tree(struct cfq_data *cfqd)
 
 	slice = max_t(unsigned, slice, CFQ_MIN_TT);
 	cfqd->workload_expires = jiffies + slice;
+	cfqd->noidle_tree_requires_idle = false;
 }
 
 /*
@@ -2597,17 +2599,27 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
 			cfq_clear_cfqq_slice_new(cfqq);
 		}
 		/*
-		 * If there are no requests waiting in this queue, and
-		 * there are other queues ready to issue requests, AND
-		 * those other queues are issuing requests within our
-		 * mean seek distance, give them a chance to run instead
-		 * of idling.
+		 * Idling is not enabled on:
+		 * - expired queues
+		 * - idle-priority queues
+		 * - async queues
+		 * - queues with still some requests queued
+		 * - when there is a close cooperator
 		 */
 		if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq))
 			cfq_slice_expired(cfqd, 1);
-		else if (cfqq_empty && !cfq_close_cooperator(cfqd, cfqq) &&
-			 sync && !rq_noidle(rq))
-			cfq_arm_slice_timer(cfqd);
+		else if (sync && cfqq_empty &&
+			 !cfq_close_cooperator(cfqd, cfqq)) {
+			cfqd->noidle_tree_requires_idle |= !rq_noidle(rq);
+			/*
+			 * Idling is enabled for SYNC_WORKLOAD.
+			 * SYNC_NOIDLE_WORKLOAD idles at the end of the tree
+			 * only if we processed at least one !rq_noidle request
+			 */
+			if (cfqd->serving_type == SYNC_WORKLOAD
+			    || cfqd->noidle_tree_requires_idle)
+				cfq_arm_slice_timer(cfqd);
+		}
 	}
 
 	if (!rq_in_driver(cfqd))