--- linux-2.6.3-ck1pre/kernel/sched.c	2004-02-16 17:05:07.545898228 +1100
+++ linux-2.6.3-ck1/kernel/sched.c	2004-02-16 17:12:17.059432103 +1100
@@ -1750,7 +1750,7 @@ need_resched:
 			if (SMT_ACTIVE) {
 				/*
 				 * If an SMT sibling task is sleeping due to
-				 * priority reasons wake it up now
+				 * priority or batch reasons wake it up now
 				 */
 				runqueue_t *smt_rq;
 				smt_rq = cpu_rq(cpu_sibling_map[(rq->cpu)]);
@@ -1806,7 +1806,8 @@ need_resched:
 		 * priority task from using an unfair proportion of the 
 		 * physical cpu's resources.
 		 */
-		if (next->mm && smt_curr->mm && !rt_task(next) && 
+		if (next->mm && smt_curr->mm && !rt_task(next) &&
+			!batch_task(smt_curr) &&
 			((next->static_prio > smt_curr->static_prio && 
 			(smt_curr->time_slice * SMT_SIBLING_IMPACT / 100) > 
 			task_timeslice(next)) || rt_task(smt_curr))) {
@@ -1815,14 +1816,31 @@ need_resched:
 		}
 		
 		/*
-		 * Reschedule a lower priority task
+		 * Prevent a batch task from running if a user
+		 * non batch task is running on an SMT sibling.
+		 */
+		if (unlikely(batch_task(next) && smt_rq->nr_running > 
+			smt_rq->nr_batch)) {
+				if (smt_curr->mm) {
+					dequeue_task(next, array);
+					enqueue_task(next, rq->batch);
+					next = rq->idle;
+				}  
+				if (smt_curr == smt_rq->idle)
+					resched_task(smt_curr);
+				goto switch_tasks;
+		}
+		
+		/*
+		 * Reschedule a lower priority or batch task
 		 * on the SMT sibling, or wake it up if it has been
 		 * put to sleep for priority reasons.
 		 */
 		if ((smt_curr != smt_rq->idle && 
 			smt_curr->static_prio > next->static_prio) ||
 			(rt_task(next) && !rt_task(smt_curr)) ||
-			(smt_curr == smt_rq->idle && smt_rq->nr_running))
+			(smt_curr == smt_rq->idle && smt_rq->nr_running) ||
+			(batch_task(smt_curr) && next->mm && !batch_task(next)))
 				resched_task(smt_curr);
 
 	}