1 files changed, 16 insertions, 48 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index d4c4996bb052..a891593a0089 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1672,10 +1672,9 @@ out:
 	preempt_enable();
 }
 
-static volatile unsigned long migration_mask;
-
-static int migration_thread(void * unused)
+static int migration_thread(void * bind_cpu)
 {
+	int cpu = cpu_logical_map((int) (long) bind_cpu);
 	struct sched_param param = { sched_priority: 99 };
 	runqueue_t *rq;
 	int ret;
@@ -1683,36 +1682,20 @@ static int migration_thread(void * unused)
 	daemonize();
 	sigfillset(&current->blocked);
 	set_fs(KERNEL_DS);
-	ret = setscheduler(0, SCHED_FIFO, &param);
-
 	/*
-	 * We have to migrate manually - there is no migration thread
-	 * to do this for us yet :-)
-	 *
-	 * We use the following property of the Linux scheduler. At
-	 * this point no other task is running, so by keeping all
-	 * migration threads running, the load-balancer will distribute
-	 * them between all CPUs equally. At that point every migration
-	 * task binds itself to the current CPU.
+	 * The first migration thread is started on CPU #0. This one can migrate
+	 * the other migration threads to their destination CPUs.
 	 */
-
-	/* wait for all migration threads to start up. */
-	while (!migration_mask)
-		yield();
-
-	for (;;) {
-		preempt_disable();
-		if (test_and_clear_bit(smp_processor_id(), &migration_mask))
-			current->cpus_allowed = 1 << smp_processor_id();
-		if (test_thread_flag(TIF_NEED_RESCHED))
-			schedule();
-		if (!migration_mask)
-			break;
-		preempt_enable();
+	if (cpu != 0) {
+		while (!cpu_rq(cpu_logical_map(0))->migration_thread)
+			yield();
+		set_cpus_allowed(current, 1UL << cpu);
 	}
+	printk("migration_task %d on cpu=%d\n",cpu,smp_processor_id());
+	ret = setscheduler(0, SCHED_FIFO, &param);
+
 	rq = this_rq();
 	rq->migration_thread = current;
-	preempt_enable();
 
 	sprintf(current->comm, "migration_CPU%d", smp_processor_id());
 
@@ -1766,33 +1749,18 @@ repeat:
 
 void __init migration_init(void)
 {
-	unsigned long tmp, orig_cache_decay_ticks;
 	int cpu;
 
-	tmp = 0;
+	current->cpus_allowed = 1UL << cpu_logical_map(0);
 	for (cpu = 0; cpu < smp_num_cpus; cpu++) {
-		if (kernel_thread(migration_thread, NULL,
+		if (kernel_thread(migration_thread, (void *) (long) cpu,
 				CLONE_FS | CLONE_FILES | CLONE_SIGNAL) < 0)
 			BUG();
-		tmp |= (1UL << cpu_logical_map(cpu));
 	}
+	current->cpus_allowed = -1L;
 
-	migration_mask = tmp;
-
-	orig_cache_decay_ticks = cache_decay_ticks;
-	cache_decay_ticks = 0;
-
-	for (cpu = 0; cpu < smp_num_cpus; cpu++) {
-		int logical = cpu_logical_map(cpu);
-
-		while (!cpu_rq(logical)->migration_thread) {
-			set_current_state(TASK_INTERRUPTIBLE);
+	for (cpu = 0; cpu < smp_num_cpus; cpu++)
+		while (!cpu_rq(cpu)->migration_thread)
 			schedule_timeout(2);
-		}
-	}
-	if (migration_mask)
-		BUG();
-
-	cache_decay_ticks = orig_cache_decay_ticks;
 }
 #endif