boolean_t swtch_pri(int pri)
{
thread_t thread = current_thread();
processor_t myprocessor;
#if NCPUS > 1
myprocessor = current_processor();
if (myprocessor->runq.count == 0 &&
myprocessor->processor_set->runq.count == 0)
return(FALSE);
#endif /* NCPUS > 1 */
/*
* XXX need to think about depression duration.
* XXX currently using min quantum.
*/
thread_depress_priority(thread, min_quantum);
counter(c_swtch_pri_block++);
thread_block(swtch_pri_continue);
if (thread->depress_priority >= 0)
(void) thread_depress_abort(thread);
myprocessor = current_processor();
return(myprocessor->runq.count > 0 ||
myprocessor->processor_set->runq.count > 0);
}
void swtch_pri_continue(void)
{
register thread_t thread = current_thread();
register processor_t myprocessor;
if (thread->depress_priority >= 0)
(void) thread_depress_abort(thread);
myprocessor = current_processor();
thread_syscall_return(myprocessor->runq.count > 0 ||
myprocessor->processor_set->runq.count > 0);
/*NOTREACHED*/
}
void thread_switch_continue(void)
{
thread_t cur_thread = current_thread();
/*
* Restore depressed priority
*/
if (cur_thread->depress_priority >= 0)
(void) thread_depress_abort(cur_thread);
thread_syscall_return(KERN_SUCCESS);
/*NOTREACHED*/
}
/*
* thread_switch:
*
* Context switch. User may supply thread hint.
*
* Fixed priority threads that call this get what they asked for
* even if that violates priority order.
*/
kern_return_t thread_switch(
mach_port_t thread_name,
int option,
mach_msg_timeout_t option_time)
{
thread_t cur_thread = current_thread();
processor_t myprocessor;
ipc_port_t port;
/*
* Process option.
*/
switch (option) {
case SWITCH_OPTION_NONE:
/*
* Nothing to do.
*/
break;
case SWITCH_OPTION_DEPRESS:
/*
* Depress priority for given time.
*/
thread_depress_priority(cur_thread, option_time);
break;
case SWITCH_OPTION_WAIT:
thread_will_wait_with_timeout(cur_thread, option_time);
break;
default:
return(KERN_INVALID_ARGUMENT);
}
#ifndef MIGRATING_THREADS /* XXX thread_run defunct */
/*
* Check and act on thread hint if appropriate.
*/
if ((thread_name != 0) &&
(ipc_port_translate_send(cur_thread->task->itk_space,
thread_name, &port) == KERN_SUCCESS)) {
/* port is locked, but it might not be active */
/*
* Get corresponding thread.
*/
if (ip_active(port) && (ip_kotype(port) == IKOT_THREAD)) {
thread_t thread;
spl_t s;
thread = (thread_t) port->ip_kobject;
/*
* Check if the thread is in the right pset. Then
* pull it off its run queue. If it
* doesn't come, then it's not eligible.
*/
s = splsched();
thread_lock(thread);
if ((thread->processor_set == cur_thread->processor_set)
&& (rem_runq(thread) != RUN_QUEUE_NULL)) {
/*
* Hah, got it!!
*/
thread_unlock(thread);
(void) splx(s);
ip_unlock(port);
/* XXX thread might disappear on us now? */
#if MACH_FIXPRI
if (thread->policy == POLICY_FIXEDPRI) {
myprocessor = current_processor();
myprocessor->quantum = thread->sched_data;
myprocessor->first_quantum = TRUE;
}
#endif /* MACH_FIXPRI */
counter(c_thread_switch_handoff++);
thread_run(thread_switch_continue, thread);
/*
* Restore depressed priority
*/
if (cur_thread->depress_priority >= 0)
(void) thread_depress_abort(cur_thread);
return(KERN_SUCCESS);
}
thread_unlock(thread);
(void) splx(s);
}
ip_unlock(port);
}
#endif /* not MIGRATING_THREADS */
/*
* No handoff hint supplied, or hint was wrong. Call thread_block() in
* hopes of running something else. If nothing else is runnable,
* thread_block will detect this. WARNING: thread_switch with no
* option will not do anything useful if the thread calling it is the
* highest priority thread (can easily happen with a collection
* of timesharing threads).
*/
#if NCPUS > 1
myprocessor = current_processor();
if (myprocessor->processor_set->runq.count > 0 ||
myprocessor->runq.count > 0)
#endif /* NCPUS > 1 */
{
counter(c_thread_switch_block++);
thread_block(thread_switch_continue);
}
/*
* Restore depressed priority
*/
if (cur_thread->depress_priority >= 0)
(void) thread_depress_abort(cur_thread);
return(KERN_SUCCESS);
}