1 files changed, 28 insertions, 4 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 8427697..7be4c79 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -598,8 +598,8 @@ cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg)
 	return cfq_target_latency * cfqg->weight / st->total_weight;
 }
 
-static inline void
-cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+static inline unsigned
+cfq_scaled_cfqq_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
 	unsigned slice = cfq_prio_to_slice(cfqd, cfqq);
 	if (cfqd->cfq_latency) {
@@ -625,6 +625,14 @@ cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 				    low_slice);
 		}
 	}
+	return slice;
+}
+
+static inline void
+cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+	unsigned slice = cfq_scaled_cfqq_slice(cfqd, cfqq);
+
 	cfqq->slice_start = jiffies;
 	cfqq->slice_end = jiffies + slice;
 	cfqq->allocated_slice = slice;
@@ -1661,8 +1669,11 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	/*
 	 * store what was left of this slice, if the queue idled/timed out
 	 */
-	if (timed_out && !cfq_cfqq_slice_new(cfqq)) {
-		cfqq->slice_resid = cfqq->slice_end - jiffies;
+	if (timed_out) {
+		if (cfq_cfqq_slice_new(cfqq))
+			cfqq->slice_resid = cfq_scaled_cfqq_slice(cfqd, cfqq);
+		else
+			cfqq->slice_resid = cfqq->slice_end - jiffies;
 		cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid);
 	}
 
@@ -3284,10 +3295,19 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
  */
 static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
+	struct cfq_queue *old_cfqq = cfqd->active_queue;
+
 	cfq_log_cfqq(cfqd, cfqq, "preempt");
 	cfq_slice_expired(cfqd, 1);
 
 	/*
+	 * workload type is changed, don't save slice, otherwise preempt
+	 * doesn't happen
+	 */
+	if (cfqq_type(old_cfqq) != cfqq_type(cfqq))
+		cfqq->cfqg->saved_workload_slice = 0;
+
+	/*
 	 * Put the new queue at the front of the of the current list,
 	 * so we know that it will be selected next.
 	 */
@@ -3412,6 +3432,10 @@ static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
 	struct cfq_io_context *cic = cfqd->active_cic;
 
+	/* If the queue already has requests, don't wait */
+	if (!RB_EMPTY_ROOT(&cfqq->sort_list))
+		return false;
+
 	/* If there are other queues in the group, don't wait */
 	if (cfqq->cfqg->nr_cfqq > 1)
 		return false;