+ if (td->latency_qd + 1 == td->latency_qd_high) {
+ /*
+ * latency_qd will not incease on lat_target_success(), so
+ * called stable. If we stick with this queue depth, the
+ * final latency is likely lower than latency_target. Fix
+ * this by increasing latency_qd_high slowly. Use a naive
+ * heuristic here. If we get lat_target_success() 3 times
+ * in a row, increase latency_qd_high by 1.
+ */
+ if (++td->latency_stable_count >= 3) {
+ td->latency_qd_high++;
+ td->latency_stable_count = 0;
+ }
+ }
+