atomic_set(&stopmachine_thread_ack, 0);
stopmachine_num_threads = 0;
stopmachine_state = STOPMACHINE_WAIT;
for_each_online_cpu(i) {
atomic_set(&stopmachine_thread_ack, 0);
stopmachine_num_threads = 0;
stopmachine_state = STOPMACHINE_WAIT;
for_each_online_cpu(i) {