[PATCH][2.5] Don't wake up tasks on offline processors

[Zwane Mwaikambo]

This patch stops waking up of tasks onto offline processors. We need this 
when migrating tasks from offline processors onto other online ones and to 
avert a livelock whilst doing so.

Index: linux-2.5.61-trojan/kernel/sched.c
===================================================================
RCS file: /build/cvsroot/linux-2.5.61/kernel/sched.c,v
retrieving revision 1.1.1.1
diff -u -r1.1.1.1 sched.c
--- linux-2.5.61-trojan/kernel/sched.c	15 Feb 2003 12:32:44 -0000	1.1.1.1
+++ linux-2.5.61-trojan/kernel/sched.c	15 Feb 2003 16:04:51 -0000
@@ -465,7 +473,8 @@
 			 * Fast-migrate the task if it's not running or runnable
 			 * currently. Do not violate hard affinity.
 			 */
-			if (unlikely(sync && !task_running(rq, p) &&
+			if (likely(cpu_online(smp_processor_id())) &&
+				unlikely(sync && !task_running(rq, p) &&
 				(task_cpu(p) != smp_processor_id()) &&
 				(p->cpus_allowed & (1UL << smp_processor_id())))) {