/* Thread0 scheduler ops (for processes that haven't linked in a full 2LS) */
static void thread0_sched_entry(void)
{
if (current_uthread)
run_current_uthread();
else
run_uthread(thread0_uth);
}
static void __pth_switch_cb(struct uthread *uthread, void *target)
{
/* by not returning, this bypasses vcore entry and event checks, though when
* we pop back out of the 2LS, we'll check notif pending. think about this
* if you put this into your 2LS. */
current_uthread = NULL;
run_uthread((struct uthread*)target);
assert(0);
}
/* Called from vcore entry. Options usually include restarting whoever was
* running there before or running a new thread. Events are handled out of
* event.c (table of function pointers, stuff like that). */
static void __attribute__((noreturn)) pth_sched_entry(void)
{
uint32_t vcoreid = vcore_id();
if (current_uthread) {
/* Prep the pthread to run any pending posix signal handlers registered
* via pthread_kill once it is restored. */
__pthread_prep_for_pending_posix_signals((pthread_t)current_uthread);
/* Run the thread itself */
run_current_uthread();
assert(0);
}
/* no one currently running, so lets get someone from the ready queue */
struct pthread_tcb *new_thread = NULL;
/* Try to get a thread. If we get one, we'll break out and run it. If not,
* we'll try to yield. vcore_yield() might return, if we lost a race and
* had a new event come in, one that may make us able to get a new_thread */
do {
handle_events(vcoreid);
__check_preempt_pending(vcoreid);
mcs_pdr_lock(&queue_lock);
new_thread = TAILQ_FIRST(&ready_queue);
if (new_thread) {
TAILQ_REMOVE(&ready_queue, new_thread, tq_next);
TAILQ_INSERT_TAIL(&active_queue, new_thread, tq_next);
threads_active++;
threads_ready--;
mcs_pdr_unlock(&queue_lock);
/* If you see what looks like the same uthread running in multiple
* places, your list might be jacked up. Turn this on. */
printd("[P] got uthread %08p on vc %d state %08p flags %08p\n",
new_thread, vcoreid,
((struct uthread*)new_thread)->state,
((struct uthread*)new_thread)->flags);
break;
}
mcs_pdr_unlock(&queue_lock);
/* no new thread, try to yield */
printd("[P] No threads, vcore %d is yielding\n", vcore_id());
/* TODO: you can imagine having something smarter here, like spin for a
* bit before yielding (or not at all if you want to be greedy). */
if (can_adjust_vcores)
vcore_yield(FALSE);
if (!parlib_wants_to_be_mcp)
sys_yield(FALSE);
} while (1);
assert(new_thread->state == PTH_RUNNABLE);
/* Prep the pthread to run any pending posix signal handlers registered
* via pthread_kill once it is restored. */
__pthread_prep_for_pending_posix_signals(new_thread);
/* Run the thread itself */
run_uthread((struct uthread*)new_thread);
assert(0);
}
/* Thread0 scheduler ops (for processes that haven't linked in a full 2LS) */
static void thread0_sched_entry(void)
{
/* TODO: support signal handling whenever we run a uthread */
if (current_uthread) {
uthread_prep_pending_signals(current_uthread);
run_current_uthread();
assert(0);
}
while (1) {
if (!thread0_info.is_blocked) {
uthread_prep_pending_signals(thread0_uth);
run_uthread(thread0_uth);
assert(0);
}
sys_yield(FALSE);
handle_events(0);
}
}
/* Called from vcore entry. Options usually include restarting whoever was
* running there before or running a new thread. Events are handled out of
* event.c (table of function pointers, stuff like that). */
void __attribute__((noreturn)) pth_sched_entry(void)
{
uint32_t vcoreid = vcore_id();
if (current_uthread) {
run_current_uthread();
assert(0);
}
/* no one currently running, so lets get someone from the ready queue */
struct pthread_tcb *new_thread = NULL;
struct mcs_lock_qnode local_qn = {0};
/* For now, let's spin and handle events til we get a thread to run. This
* will help catch races, instead of only having one core ever run a thread
* (if there is just one, etc). Also, we don't need the EVENT_IPIs for this
* to work (since we poll handle_events() */
while (!new_thread) {
handle_events(vcoreid);
mcs_lock_notifsafe(&queue_lock, &local_qn);
new_thread = TAILQ_FIRST(&ready_queue);
if (new_thread) {
TAILQ_REMOVE(&ready_queue, new_thread, next);
TAILQ_INSERT_TAIL(&active_queue, new_thread, next);
threads_active++;
threads_ready--;
}
mcs_unlock_notifsafe(&queue_lock, &local_qn);
}
/* Instead of yielding, you could spin, turn off the core, set an alarm,
* whatever. You want some logic to decide this. Uthread code wil have
* helpers for this (like how we provide run_uthread()) */
if (!new_thread) {
/* Note, we currently don't get here (due to the while loop) */
printd("[P] No threads, vcore %d is yielding\n", vcore_id());
/* Not actually yielding - just spin for now, so we can get syscall
* unblocking events */
vcore_idle();
//sys_yield(0);
assert(0);
}
assert(((struct uthread*)new_thread)->state != UT_RUNNING);
run_uthread((struct uthread*)new_thread);
assert(0);
}
