/*
* Get the darwin background state of the originator. If the current
* process app type is App, then it is the originator, else if it is
* a Daemon, then creator of the Resource Accounting attribute of
* the current thread voucher is the originator of the work.
*/
int
proc_get_originatorbgstate(uint32_t *is_backgrounded)
{
uint32_t bgstate;
proc_t p = current_proc();
uint32_t flagsp = 0;
kern_return_t kr;
pid_t pid;
int ret;
thread_t thread = current_thread();
bgstate = proc_get_effective_thread_policy(thread, TASK_POLICY_DARWIN_BG);
/* If current thread or task backgrounded, return background */
if (bgstate) {
*is_backgrounded = 1;
return 0;
}
/* Check if current process app type is App, then return foreground */
proc_get_darwinbgstate(p->task, &flagsp);
if ((flagsp & PROC_FLAG_APPLICATION) == PROC_FLAG_APPLICATION) {
*is_backgrounded = 0;
return 0;
}
/*
* Get the current voucher origin pid and it's bgstate.The pid
* returned here might not be valid or may have been recycled.
*/
kr = thread_get_current_voucher_origin_pid(&pid);
if (kr != KERN_SUCCESS) {
if (kr == KERN_INVALID_TASK)
return ESRCH;
else if (kr == KERN_INVALID_VALUE)
return ENOATTR;
else
return EINVAL;
}
ret = proc_pidbackgrounded(pid, is_backgrounded);
return ret;
}
/*
* thread_switch:
*
* Context switch. User may supply thread hint.
*/
kern_return_t
thread_switch(
struct thread_switch_args *args)
{
thread_t thread = THREAD_NULL;
thread_t self = current_thread();
mach_port_name_t thread_name = args->thread_name;
int option = args->option;
mach_msg_timeout_t option_time = args->option_time;
uint32_t scale_factor = NSEC_PER_MSEC;
boolean_t reenable_workq_callback = FALSE;
boolean_t depress_option = FALSE;
boolean_t wait_option = FALSE;
/*
* Validate and process option.
*/
switch (option) {
case SWITCH_OPTION_NONE:
workqueue_thread_yielded();
break;
case SWITCH_OPTION_WAIT:
wait_option = TRUE;
workqueue_thread_yielded();
break;
case SWITCH_OPTION_DEPRESS:
depress_option = TRUE;
workqueue_thread_yielded();
break;
case SWITCH_OPTION_DISPATCH_CONTENTION:
scale_factor = NSEC_PER_USEC;
wait_option = TRUE;
if (thread_switch_disable_workqueue_sched_callback())
reenable_workq_callback = TRUE;
break;
case SWITCH_OPTION_OSLOCK_DEPRESS:
depress_option = TRUE;
if (thread_switch_disable_workqueue_sched_callback())
reenable_workq_callback = TRUE;
break;
case SWITCH_OPTION_OSLOCK_WAIT:
wait_option = TRUE;
if (thread_switch_disable_workqueue_sched_callback())
reenable_workq_callback = TRUE;
break;
default:
return (KERN_INVALID_ARGUMENT);
}
/*
* Translate the port name if supplied.
*/
if (thread_name != MACH_PORT_NULL) {
ipc_port_t port;
if (ipc_port_translate_send(self->task->itk_space,
thread_name, &port) == KERN_SUCCESS) {
ip_reference(port);
ip_unlock(port);
thread = convert_port_to_thread(port);
ip_release(port);
if (thread == self) {
thread_deallocate(thread);
thread = THREAD_NULL;
}
}
}
if (option == SWITCH_OPTION_OSLOCK_DEPRESS || option == SWITCH_OPTION_OSLOCK_WAIT) {
if (thread != THREAD_NULL) {
if (thread->task != self->task) {
/*
* OSLock boosting only applies to other threads
* in your same task (even if you have a port for
* a thread in another task)
*/
thread_deallocate(thread);
thread = THREAD_NULL;
} else {
/*
* Attempt to kick the lock owner up to our same IO throttling tier.
* If the thread is currently blocked in throttle_lowpri_io(),
* it will immediately break out.
*
* TODO: SFI break out?
*/
int new_policy = proc_get_effective_thread_policy(self, TASK_POLICY_IO);
set_thread_iotier_override(thread, new_policy);
}
}
}
/*
* Try to handoff if supplied.
*/
if (thread != THREAD_NULL) {
spl_t s = splsched();
/* This may return a different thread if the target is pushing on something */
thread_t pulled_thread = thread_run_queue_remove_for_handoff(thread);
KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED,MACH_SCHED_THREAD_SWITCH)|DBG_FUNC_NONE,
thread_tid(thread), thread->state,
pulled_thread ? TRUE : FALSE, 0, 0);
if (pulled_thread != THREAD_NULL) {
/* We can't be dropping the last ref here */
thread_deallocate_safe(thread);
if (wait_option)
assert_wait_timeout((event_t)assert_wait_timeout, THREAD_ABORTSAFE,
option_time, scale_factor);
else if (depress_option)
thread_depress_ms(option_time);
self->saved.swtch.option = option;
self->saved.swtch.reenable_workq_callback = reenable_workq_callback;
thread_run(self, (thread_continue_t)thread_switch_continue, NULL, pulled_thread);
/* NOTREACHED */
panic("returned from thread_run!");
}
splx(s);
thread_deallocate(thread);
}
if (wait_option)
assert_wait_timeout((event_t)assert_wait_timeout, THREAD_ABORTSAFE, option_time, scale_factor);
else if (depress_option)
thread_depress_ms(option_time);
self->saved.swtch.option = option;
self->saved.swtch.reenable_workq_callback = reenable_workq_callback;
thread_block_reason((thread_continue_t)thread_switch_continue, NULL, AST_YIELD);
if (depress_option)
thread_depress_abort_internal(self);
if (reenable_workq_callback)
thread_switch_enable_workqueue_sched_callback();
return (KERN_SUCCESS);
}
