X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fsched.c;h=2e8a146dd0660a8e8a914ee0936e66832934b33d;hb=5ce74abe788a26698876e66b9c9ce7e7acc25413;hp=dd153d6f8a04b7c2ba8c4954b8628ef70ad307ce;hpb=019ff2d57b0bbe77d1eca19f5b634e5e7ff2a0b8;p=linux-2.6-omap-h63xx.git

diff --git a/kernel/sched.c b/kernel/sched.c
index dd153d6f8a0..2e8a146dd06 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -664,6 +664,48 @@ static int effective_prio(task_t *p)
 	return prio;
 }
 
+/*
+ * 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;
+}
+
 /*
  * __activate_task - move a task to the runqueue.
  */
@@ -671,7 +713,7 @@ static void __activate_task(task_t *p, runqueue_t *rq)
 {
 	prio_array_t *target = rq->active;
 
-	if (batch_task(p))
+	if (unlikely(batch_task(p) || expired_starving(rq)))
 		target = rq->expired;
 	enqueue_task(p, target);
 	rq->nr_running++;
@@ -2489,22 +2531,6 @@ unsigned long long current_sched_time(const task_t *tsk)
 	return ns;
 }
 
-/*
- * 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:
- */
-#define EXPIRED_STARVING(rq) \
-	((STARVATION_LIMIT && ((rq)->expired_timestamp && \
-		(jiffies - (rq)->expired_timestamp >= \
-			STARVATION_LIMIT * ((rq)->nr_running) + 1))) || \
-			((rq)->curr->static_prio > (rq)->best_expired_prio))
-
 /*
  * Account user cpu time to a process.
  * @p: the process that the cpu time gets accounted to
@@ -2640,7 +2666,7 @@ void scheduler_tick(void)
 
 		if (!rq->expired_timestamp)
 			rq->expired_timestamp = jiffies;
-		if (!TASK_INTERACTIVE(p) || EXPIRED_STARVING(rq)) {
+		if (!TASK_INTERACTIVE(p) || expired_starving(rq)) {
 			enqueue_task(p, rq->expired);
 			if (p->static_prio < rq->best_expired_prio)
 				rq->best_expired_prio = p->static_prio;