1 files changed, 22 insertions, 10 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 15f7238f527f..a5de31f76d3b 100644
--- a/block/cfq-iosched.c
+++ b/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))