+/*
+ * We place interactive tasks back into the active array, if possible.
+ *
+ * To guarantee that this does not starve expired tasks we ignore the
+ * interactivity of a task if the first expired task had to wait more
+ * than a 'reasonable' amount of time. This deadline timeout is
+ * load-dependent, as the frequency of array switched decreases with
+ * increasing number of running tasks. We also ignore the interactivity
+ * if a better static_prio task has expired, and switch periodically
+ * regardless, to ensure that highly interactive tasks do not starve
+ * the less fortunate for unreasonably long periods.
+ */
+static inline int expired_starving(runqueue_t *rq)
+{
+ int limit;
+
+ /*
+ * Arrays were recently switched, all is well
+ */
+ if (!rq->expired_timestamp)
+ return 0;
+
+ limit = STARVATION_LIMIT * rq->nr_running;
+
+ /*
+ * It's time to switch arrays
+ */
+ if (jiffies - rq->expired_timestamp >= limit)
+ return 1;
+
+ /*
+ * There's a better selection in the expired array
+ */
+ if (rq->curr->static_prio > rq->best_expired_prio)
+ return 1;
+
+ /*
+ * All is well
+ */
+ return 0;
+}
+