Index: linux-2.6.8.1/include/linux/sched.h
===================================================================
--- linux-2.6.8.1.orig/include/linux/sched.h	2004-08-15 15:01:13.887305672 +1000
+++ linux-2.6.8.1/include/linux/sched.h	2004-08-15 15:01:15.117113043 +1000
@@ -127,9 +127,10 @@ extern unsigned long nr_iowait(void);
 #define SCHED_FIFO		1
 #define SCHED_RR		2
 #define SCHED_BATCH		3
+#define SCHED_ISO		4
 
 #define SCHED_MIN		0
-#define SCHED_MAX		3
+#define SCHED_MAX		4
 
 #define SCHED_RANGE(policy)	((policy) >= SCHED_MIN && \
 					(policy) <= SCHED_MAX)
@@ -312,6 +313,7 @@ struct signal_struct {
 
 #define rt_task(p)		((p)->prio < MAX_RT_PRIO)
 #define batch_task(p)		((p)->policy == SCHED_BATCH)
+#define iso_task(p)		((p)->policy == SCHED_ISO)
 
 /*
  * Some day this will be a full-fledged user tracking system..
Index: linux-2.6.8.1/kernel/sched.c
===================================================================
--- linux-2.6.8.1.orig/kernel/sched.c	2004-08-15 15:01:13.890305202 +1000
+++ linux-2.6.8.1/kernel/sched.c	2004-08-15 15:01:53.693073042 +1000
@@ -247,6 +247,8 @@ static unsigned int burst(task_t *p)
 {
 	if (likely(!rt_task(p))) {
 		unsigned int task_user_prio = TASK_USER_PRIO(p);
+		if (iso_task(p))
+			task_user_prio /= 2;
 		return 39 - task_user_prio;
 	} else
 		return p->burst;
@@ -285,6 +287,18 @@ static unsigned int slice(task_t *p)
  */
 int sched_interactive = 1;
 
+static int rr_interval(task_t * p)
+{
+	int rr_interval = RR_INTERVAL();
+	if (batch_task(p))
+		rr_interval *= 10;
+	else if (iso_task(p))
+		rr_interval /= 2;
+	if (!rr_interval)
+		rr_interval = 1;
+	return rr_interval;
+}
+
 /*
  * effective_prio - dynamic priority dependent on burst.
  * The priority normally decreases by one each RR_INTERVAL.
@@ -293,7 +307,7 @@ int sched_interactive = 1;
  */
 static int effective_prio(task_t *p)
 {
-	int prio;
+	int prio, rr;
 	unsigned int full_slice, used_slice, first_slice;
 	unsigned int best_burst;
 	if (rt_task(p))
@@ -311,20 +325,22 @@ static int effective_prio(task_t *p)
 	}
 
 	best_burst = burst(p);
-	if (p->flags & PF_UISLEEP && sched_interactive && best_burst && p->mm)
-		best_burst--;
+	if (p->flags & PF_UISLEEP && sched_interactive && best_burst && 
+		p->mm && !iso_task(p))
+			best_burst--;
 	full_slice = slice(p);
+	rr = rr_interval(p);
 	used_slice = full_slice - p->slice;
 	if (p->burst > best_burst)
 		p->burst = best_burst;
-	first_slice = RR_INTERVAL();
-	if (sched_interactive && !sched_compute && p->mm)
+	first_slice = rr;
+	if (sched_interactive && !sched_compute && p->mm && !iso_task(p))
 		first_slice *= (p->burst + 1);
 	prio = MAX_PRIO - 2 - best_burst;
 
 	if (used_slice < first_slice)
 		return prio;
-	prio += 1 + (used_slice - first_slice) / RR_INTERVAL();
+	prio += 1 + (used_slice - first_slice) / rr;
 	if (prio > MAX_PRIO - 2)
 		prio = MAX_PRIO - 2;
 	return prio;
@@ -338,7 +354,7 @@ static int effective_prio(task_t *p)
 static void recalc_task_prio(task_t *p, unsigned long long now)
 {
 	unsigned long sleep_time = now - p->timestamp;
-	unsigned int rr = RR_INTERVAL();
+	unsigned int rr = rr_interval(p);
 	if (p->flags & PF_FORKED || 
 		(NS_TO_JIFFIES(p->runtime + sleep_time) < rr / 2 || 
 		((!sched_interactive || sched_compute) && 
@@ -382,7 +398,7 @@ static void activate_task(task_t *p, run
 	recalc_task_prio(p, now);
 	p->prio = effective_prio(p);
 	p->flags &= ~PF_UISLEEP;
-	p->time_slice = RR_INTERVAL();
+	p->time_slice = rr_interval(p);
 	if (batch_task(p))
 		p->time_slice = p->slice;
 	p->timestamp = now;
@@ -1803,19 +1819,19 @@ void scheduler_tick(int user_ticks, int 
 		dec_burst(p);
 		p->slice = slice(p);
 		p->prio = effective_prio(p);
-		p->time_slice = RR_INTERVAL();
+		p->time_slice = rr_interval(p);
 		enqueue_task(p, rq);
 		goto out_unlock;
 	}
 	/*
 	 * Tasks that run out of time_slice but still have slice left get
-	 * requeued with a lower priority && RR_INTERVAL time_slice.
+	 * requeued with a lower priority && rr_interval time_slice.
 	 */
 	if (!--p->time_slice) {
 		set_tsk_need_resched(p);
 		dequeue_task(p, rq);
 		p->prio = effective_prio(p);
-		p->time_slice = RR_INTERVAL();
+		p->time_slice = rr_interval(p);
 		enqueue_task(p, rq);
 		goto out_unlock;
 	}
@@ -2457,7 +2473,11 @@ static int setscheduler(pid_t pid, int p
 
 	retval = -EPERM;
 	if (SCHED_RT(policy) && !capable(CAP_SYS_NICE))
-		goto out_unlock;
+		/*
+		 * If the caller requested an RT policy without having the
+		 * necessary rights, we downgrade the policy to SCHED_ISO.
+		 */
+		policy = SCHED_ISO;
 	if ((current->euid != p->euid) && (current->euid != p->uid) &&
 	    !capable(CAP_SYS_NICE))
 		goto out_unlock;
@@ -2792,6 +2812,7 @@ asmlinkage long sys_sched_get_priority_m
 		break;
 	case SCHED_NORMAL:
 	case SCHED_BATCH:
+	case SCHED_ISO:
 		ret = 0;
 		break;
 	}
@@ -2816,6 +2837,7 @@ asmlinkage long sys_sched_get_priority_m
 		break;
 	case SCHED_NORMAL:
 	case SCHED_BATCH:
+	case SCHED_ISO:
 		ret = 0;
 	}
 	return ret;