+/*
+ * Update hw_tag based on peak queue depth over 50 samples under
+ * sufficient load.
+ */
+static void cfq_update_hw_tag(struct cfq_data *cfqd)
+{
+ if (cfqd->rq_in_driver > cfqd->rq_in_driver_peak)
+ cfqd->rq_in_driver_peak = cfqd->rq_in_driver;
+
+ if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN &&
+ cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN)
+ return;
+
+ if (cfqd->hw_tag_samples++ < 50)
+ return;
+
+ if (cfqd->rq_in_driver_peak >= CFQ_HW_QUEUE_MIN)
+ cfqd->hw_tag = 1;
+ else
+ cfqd->hw_tag = 0;
+
+ cfqd->hw_tag_samples = 0;
+ cfqd->rq_in_driver_peak = 0;
+}
+