void
erts_thr_progress_finalize_wait(ErtsSchedulerData *esdp)
{
ErtsThrPrgrData *tpd = thr_prgr_data(esdp);
ErtsThrPrgrVal current, val;
#ifdef ERTS_ENABLE_LOCK_CHECK
erts_lc_check_exact(NULL, 0);
#endif
/*
* We aren't allowed to continue until our thread
* progress is past global current.
*/
val = current = read_acqb(&erts_thr_prgr__.current);
while (1) {
val++;
if (val == ERTS_THR_PRGR_VAL_WAITING)
val = 0;
tpd->confirmed = val;
set_mb(&intrnl->thr[tpd->id].data.current, val);
val = read_acqb(&erts_thr_prgr__.current);
if (current == val)
break;
current = val;
}
if (block_count_inc())
block_thread(tpd);
if (update(tpd))
leader_update(tpd);
}
thread_id_t iteration_begin(iteration_t iter)
{
iter_ = iter;
running_threads_count = thread_count;
finished_thread_count_ = 0;
timed_thread_count_ = 0;
spurious_thread_count_ = 0;
dynamic_thread_count_ = 0;
for (thread_id_t i = 0; i != thread_count; ++i)
{
running_threads.push_back(i);
threads_[i].reset(params_);
}
for (thread_id_t i = thread_count - total_dynamic_threads_; i != thread_count; ++i)
{
dynamic_threads_[dynamic_thread_count_++] = &threads_[i];
block_thread(i, false);
}
thread_id_t const th = self().iteration_begin_impl();
thread_ = &threads_[th];
return th;
}
/* Gain ownership of a mutex object or block until it becomes free */
void mutex_lock(struct mutex *m)
{
struct thread_entry *current = __running_self_entry();
if(current == m->blocker.thread)
{
/* current thread already owns this mutex */
m->recursion++;
return;
}
/* lock out other cores */
corelock_lock(&m->cl);
/* must read thread again inside cs (a multiprocessor concern really) */
if(LIKELY(m->blocker.thread == NULL))
{
/* lock is open */
m->blocker.thread = current;
corelock_unlock(&m->cl);
return;
}
/* block until the lock is open... */
disable_irq();
block_thread(current, TIMEOUT_BLOCK, &m->queue, &m->blocker);
corelock_unlock(&m->cl);
/* ...and turn control over to next thread */
switch_thread();
}
thread_finish_result thread_finished()
{
RL_VERIFY(thread_->state_ == thread_state_running);
block_thread(thread_->index_, false);
thread_->state_ = thread_state_finished;
finished_thread_count_ += 1;
self().thread_finished_impl();
retry:
if (finished_thread_count_ == thread_count)
{
return thread_finish_result_last;
}
else if (is_deadlock())
{
if (dynamic_thread_count_)
{
while (dynamic_thread_count_)
{
thread_info_t* th = dynamic_threads_[--dynamic_thread_count_];
unblock_thread(th->index_);
}
goto retry;
}
return thread_finish_result_deadlock;
}
else
{
return thread_finish_result_normal;
}
}
int block_threads(torque_ctx *ctx){
int ret = 0;
if(ctx->ev){
ret = block_thread(ctx->ev->nexttid);
}
return ret;
}
/* Down the semaphore's count or wait for 'timeout' ticks for it to go up if
* it is already 0. 'timeout' as TIMEOUT_NOBLOCK (0) will not block and may
* safely be used in an ISR. */
int semaphore_wait(struct semaphore *s, int timeout)
{
int ret = OBJ_WAIT_TIMEDOUT;
int oldlevel = disable_irq_save();
corelock_lock(&s->cl);
int count = s->count;
if(LIKELY(count > 0))
{
/* count is not zero; down it */
s->count = count - 1;
ret = OBJ_WAIT_SUCCEEDED;
}
else if(timeout != 0)
{
ASSERT_CPU_MODE(CPU_MODE_THREAD_CONTEXT, oldlevel);
/* too many waits - block until count is upped... */
struct thread_entry *current = __running_self_entry();
block_thread(current, timeout, &s->queue, NULL);
corelock_unlock(&s->cl);
/* ...and turn control over to next thread */
switch_thread();
/* if explicit wake indicated; do no more */
if(LIKELY(!wait_queue_ptr(current)))
return OBJ_WAIT_SUCCEEDED;
disable_irq();
corelock_lock(&s->cl);
/* see if anyone got us after the expired wait */
if(wait_queue_try_remove(current))
{
count = s->count;
if(count > 0)
{
/* down it lately */
s->count = count - 1;
ret = OBJ_WAIT_SUCCEEDED;
}
}
}
/* else just polling it */
corelock_unlock(&s->cl);
restore_irq(oldlevel);
return ret;
}
void thread_wait(unsigned int thread_id)
{
struct thread_entry *current = cores[CURRENT_CORE].running;
struct thread_entry *thread = thread_id_entry(thread_id);
if (thread->id == thread_id && thread->state != STATE_KILLED)
{
current->bqp = &thread->queue;
block_thread(current);
switch_thread();
}
}
/*
* Will block the thread if needed, otherwise will just decrement
* the semaphore's value
*
* @Param - Pointer to the semaphore that will impose waiting
*/
void mysem_wait(Semaphore* sem){
DISABLE_INTERRUPTS();
sem->value--;
tcb* currentThread = get_mythread();
if(sem->value < 0){
mythread_block(currentThread);
block_thread(sem, currentThread);
mysem_printQueue(sem);
}
ENABLE_INTERRUPTS();
// Stall the thread until the thread becomes READY
while(currentThread->state==BLOCKED){
asm("nop");
}
}
static inline int
reap_thread(pthread_t tid){
int ret = 0;
// POSIX has a special case for process-autodirected signals; kill(2)
// does not return until at least one signal is delivered. This works
// around a race condition (see block_thread()) *most* of the time.
// There's two problems with it: should some other thread have
// EVTHREAD_TERM unblocked, this breaks (but they shouldn't be doing
// that anyway), and should some other signal already be pending, it
// breaks (we're only guaranteed that *one* signal gets delivered
// before we return, so we can still hit the block_thread() early).
ret |= kill(getpid(),EVTHREAD_TERM);
ret |= block_thread(tid);
return ret;
}
static erts_aint32_t
thr_progress_block(ErtsThrPrgrData *tpd, int wait)
{
erts_tse_t *event = NULL; /* Remove erroneous warning... sigh... */
erts_aint32_t lflgs, bc;
if (tpd->is_blocking++)
return (erts_aint32_t) 0;
while (1) {
lflgs = erts_atomic32_read_bor_nob(&intrnl->misc.data.lflgs,
ERTS_THR_PRGR_LFLG_BLOCK);
if (lflgs & ERTS_THR_PRGR_LFLG_BLOCK)
block_thread(tpd);
else
break;
}
#if ERTS_THR_PRGR_PRINT_BLOCKERS
erts_fprintf(stderr, "block(%d)\n", tpd->id);
#endif
ASSERT(ERTS_AINT_NULL
== erts_atomic_read_nob(&intrnl->misc.data.blocker_event));
if (wait) {
event = erts_tse_fetch();
erts_tse_reset(event);
erts_atomic_set_nob(&intrnl->misc.data.blocker_event,
(erts_aint_t) event);
}
if (tpd->is_managed)
erts_atomic32_dec_nob(&intrnl->misc.data.block_count);
bc = erts_atomic32_read_band_mb(&intrnl->misc.data.block_count,
~ERTS_THR_PRGR_BC_FLG_NOT_BLOCKING);
bc &= ~ERTS_THR_PRGR_BC_FLG_NOT_BLOCKING;
if (wait) {
while (bc != 0) {
erts_tse_wait(event);
erts_tse_reset(event);
bc = erts_atomic32_read_acqb(&intrnl->misc.data.block_count);
}
}
return bc;
}
bool park_current_thread(bool is_timed, bool allow_spurious_wakeup)
{
if (is_timed)
{
timed_threads_[timed_thread_count_++] = thread_;
RL_VERIFY(timed_thread_count_ <= thread_count);
}
if (allow_spurious_wakeup)
{
spurious_threads_[spurious_thread_count_++] = thread_;
RL_VERIFY(spurious_thread_count_ <= thread_count);
}
block_thread(thread_->index_, true);
return is_deadlock() ? false : true;
}
/* Down the semaphore's count or wait for 'timeout' ticks for it to go up if
* it is already 0. 'timeout' as TIMEOUT_NOBLOCK (0) will not block and may
* safely be used in an ISR. */
int semaphore_wait(struct semaphore *s, int timeout)
{
int ret;
int oldlevel;
int count;
oldlevel = disable_irq_save();
corelock_lock(&s->cl);
count = s->count;
if(LIKELY(count > 0))
{
/* count is not zero; down it */
s->count = count - 1;
ret = OBJ_WAIT_SUCCEEDED;
}
else if(timeout == 0)
{
/* just polling it */
ret = OBJ_WAIT_TIMEDOUT;
}
else
{
/* too many waits - block until count is upped... */
struct thread_entry * current = thread_self_entry();
IF_COP( current->obj_cl = &s->cl; )
current->bqp = &s->queue;
/* return value will be OBJ_WAIT_SUCCEEDED after wait if wake was
* explicit in semaphore_release */
current->retval = OBJ_WAIT_TIMEDOUT;
if(timeout > 0)
block_thread_w_tmo(current, timeout); /* ...or timed out... */
else
block_thread(current); /* -timeout = infinite */
corelock_unlock(&s->cl);
/* ...and turn control over to next thread */
switch_thread();
return current->retval;
}
static ERTS_INLINE int
leader_update(ErtsThrPrgrData *tpd)
{
#ifdef ERTS_ENABLE_LOCK_CHECK
erts_lc_check_exact(NULL, 0);
#endif
if (!tpd->leader) {
/* Probably need to block... */
block_thread(tpd);
}
else {
ErtsThrPrgrVal current;
int ix, chk_next_ix, umrefc_ix, my_ix, no_managed, waiting_unmanaged;
erts_aint32_t lflgs;
ErtsThrPrgrVal next;
erts_aint_t refc;
my_ix = tpd->id;
if (tpd->leader_state.current == ERTS_THR_PRGR_VAL_WAITING) {
/* Took over as leader from another thread */
tpd->leader_state.current = read_nob(&erts_thr_prgr__.current);
tpd->leader_state.next = tpd->leader_state.current;
tpd->leader_state.next++;
if (tpd->leader_state.next == ERTS_THR_PRGR_VAL_WAITING)
tpd->leader_state.next = 0;
tpd->leader_state.chk_next_ix = intrnl->misc.data.chk_next_ix;
tpd->leader_state.umrefc_ix.waiting = intrnl->misc.data.umrefc_ix.waiting;
tpd->leader_state.umrefc_ix.current =
(int) erts_atomic32_read_nob(&intrnl->misc.data.umrefc_ix.current);
if (tpd->confirmed == tpd->leader_state.current) {
ErtsThrPrgrVal val = tpd->leader_state.current + 1;
if (val == ERTS_THR_PRGR_VAL_WAITING)
val = 0;
tpd->confirmed = val;
set_mb(&intrnl->thr[my_ix].data.current, val);
}
}
next = tpd->leader_state.next;
waiting_unmanaged = 0;
umrefc_ix = -1; /* Shut up annoying warning */
chk_next_ix = tpd->leader_state.chk_next_ix;
no_managed = intrnl->managed.no;
ASSERT(0 <= chk_next_ix && chk_next_ix <= no_managed);
/* Check manged threads */
if (chk_next_ix < no_managed) {
for (ix = chk_next_ix; ix < no_managed; ix++) {
ErtsThrPrgrVal tmp;
if (ix == my_ix)
continue;
tmp = read_nob(&intrnl->thr[ix].data.current);
if (tmp != next && tmp != ERTS_THR_PRGR_VAL_WAITING) {
tpd->leader_state.chk_next_ix = ix;
ASSERT(erts_thr_progress_has_passed__(next, tmp));
goto done;
}
}
}
/* Check unmanged threads */
waiting_unmanaged = tpd->leader_state.umrefc_ix.waiting != -1;
umrefc_ix = (waiting_unmanaged
? tpd->leader_state.umrefc_ix.waiting
: tpd->leader_state.umrefc_ix.current);
refc = erts_atomic_read_nob(&intrnl->umrefc[umrefc_ix].refc);
ASSERT(refc >= 0);
if (refc != 0) {
int new_umrefc_ix;
if (waiting_unmanaged)
goto done;
new_umrefc_ix = (umrefc_ix + 1) & 0x1;
tpd->leader_state.umrefc_ix.waiting = umrefc_ix;
tpd->leader_state.chk_next_ix = no_managed;
erts_atomic32_set_nob(&intrnl->misc.data.umrefc_ix.current,
(erts_aint32_t) new_umrefc_ix);
ETHR_MEMBAR(ETHR_StoreLoad);
refc = erts_atomic_read_nob(&intrnl->umrefc[umrefc_ix].refc);
ASSERT(refc >= 0);
waiting_unmanaged = 1;
if (refc != 0)
goto done;
}
/* Make progress */
current = next;
next++;
if (next == ERTS_THR_PRGR_VAL_WAITING)
next = 0;
set_nob(&intrnl->thr[my_ix].data.current, next);
set_mb(&erts_thr_prgr__.current, current);
tpd->confirmed = next;
tpd->leader_state.next = next;
tpd->leader_state.current = current;
#if ERTS_THR_PRGR_PRINT_VAL
if (current % 1000 == 0)
erts_fprintf(stderr, "%b64u\n", current);
#endif
handle_wakeup_requests(current);
if (waiting_unmanaged) {
waiting_unmanaged = 0;
tpd->leader_state.umrefc_ix.waiting = -1;
erts_atomic32_read_band_nob(&intrnl->misc.data.lflgs,
~ERTS_THR_PRGR_LFLG_WAITING_UM);
}
tpd->leader_state.chk_next_ix = 0;
done:
if (tpd->active) {
lflgs = erts_atomic32_read_nob(&intrnl->misc.data.lflgs);
if (lflgs & ERTS_THR_PRGR_LFLG_BLOCK)
(void) block_thread(tpd);
}
else {
int force_wakeup_check = 0;
erts_aint32_t set_flags = ERTS_THR_PRGR_LFLG_NO_LEADER;
tpd->leader = 0;
tpd->leader_state.current = ERTS_THR_PRGR_VAL_WAITING;
#if ERTS_THR_PRGR_PRINT_LEADER
erts_fprintf(stderr, "L <- %d\n", tpd->id);
#endif
ERTS_THR_PROGRESS_STATE_DEBUG_SET_LEADER(tpd->id, 0);
intrnl->misc.data.umrefc_ix.waiting
= tpd->leader_state.umrefc_ix.waiting;
if (waiting_unmanaged)
set_flags |= ERTS_THR_PRGR_LFLG_WAITING_UM;
lflgs = erts_atomic32_read_bor_relb(&intrnl->misc.data.lflgs,
set_flags);
lflgs |= set_flags;
if (lflgs & ERTS_THR_PRGR_LFLG_BLOCK)
lflgs = block_thread(tpd);
if (waiting_unmanaged) {
/* Need to check umrefc again */
ETHR_MEMBAR(ETHR_StoreLoad);
refc = erts_atomic_read_nob(&intrnl->umrefc[umrefc_ix].refc);
if (refc == 0) {
/* Need to force wakeup check */
force_wakeup_check = 1;
}
}
if ((force_wakeup_check
|| ((lflgs & (ERTS_THR_PRGR_LFLG_NO_LEADER
| ERTS_THR_PRGR_LFLG_WAITING_UM
| ERTS_THR_PRGR_LFLG_ACTIVE_MASK))
== ERTS_THR_PRGR_LFLG_NO_LEADER))
&& got_sched_wakeups()) {
/* Someone need to make progress */
wakeup_managed(0);
}
}
}
return tpd->leader;
}