diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 8427697..7bfea53c 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3284,10 +3284,19 @@
  */
 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.
 	 */