diff -urN oldtree/include/linux/sched.h newtree/include/linux/sched.h
--- oldtree/include/linux/sched.h	2006-09-29 14:03:22.000000000 -0400
+++ newtree/include/linux/sched.h	2006-09-29 14:08:46.000000000 -0400
@@ -508,6 +508,9 @@
 #define is_rt_policy(p)		((p) != SCHED_NORMAL && (p) != SCHED_BATCH)
 #define has_rt_policy(p)	unlikely(is_rt_policy((p)->policy))
 
+/* Must be high prio: stop_machine expects to yield to it. */
+#define MIGRATION_THREAD_PRIO (MAX_RT_PRIO-20)
+
 /*
  * Some day this will be a full-fledged user tracking system..
  */
diff -urN oldtree/include/linux/stop_machine.h newtree/include/linux/stop_machine.h
--- oldtree/include/linux/stop_machine.h	2006-09-29 13:50:42.000000000 -0400
+++ newtree/include/linux/stop_machine.h	2006-09-29 14:08:46.000000000 -0400
@@ -8,6 +8,9 @@
 #include <asm/system.h>
 
 #if defined(CONFIG_STOP_MACHINE) && defined(CONFIG_SMP)
+
+#define STOP_MACHINE_PRIO (MAX_RT_PRIO-20)
+
 /**
  * stop_machine_run: freeze the machine on all CPUs and run this function
  * @fn: the function to run
diff -urN oldtree/kernel/sched.c newtree/kernel/sched.c
--- oldtree/kernel/sched.c	2006-09-29 14:08:38.000000000 -0400
+++ newtree/kernel/sched.c	2006-09-29 14:08:46.000000000 -0400
@@ -5206,9 +5206,8 @@
 			return NOTIFY_BAD;
 		p->flags |= PF_NOFREEZE;
 		kthread_bind(p, cpu);
-		/* Must be high prio: stop_machine expects to yield to it. */
 		rq = task_rq_lock(p, &flags);
-		__setscheduler(p, SCHED_FIFO, MAX_RT_PRIO-1);
+		__setscheduler(p, SCHED_FIFO, MIGRATION_THREAD_PRIO);
 		task_rq_unlock(rq, &flags);
 		cpu_rq(cpu)->migration_thread = p;
 		break;
diff -urN oldtree/kernel/stop_machine.c newtree/kernel/stop_machine.c
--- oldtree/kernel/stop_machine.c	2006-09-29 14:03:22.000000000 -0400
+++ newtree/kernel/stop_machine.c	2006-09-29 14:08:46.000000000 -0400
@@ -89,7 +89,7 @@
 static int stop_machine(void)
 {
 	int i, ret = 0;
-	struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
+	struct sched_param param = { .sched_priority = STOP_MACHINE_PRIO };
 
 	/* One high-prio thread per cpu.  We'll do this one. */
 	sched_setscheduler(current, SCHED_FIFO, &param);