def _shutdown_workers(self):
if not self.shutdown:
self.shutdown = True
# removes pids from the C side data structure first so worker
# termination afterwards won't trigger false positive error report.
if self.worker_pids_set:
_remove_worker_pids(id(self))
self.worker_pids_set = False
self.done_event.set()
if self.pin_memory:
# Sending `None` to `pin_memory_thread` must be before
# stopping worker processes because the workers may leave
# corrupted data in `worker_result_queue`, causing
# `pin_memory_thread` unable to read and terminate properly.
self.worker_result_queue.put(None)
# Workers can't be waiting to put be cause their output queue
# is a multiprocessing.Queue and its .put is non-blocking.
# They can only be waiting to get, so we put `None` here.
for _w in self.workers:
# Putting as many None as workers to ensure worker will get one
self.batch_queue.put(None)
for w in self.workers:
w.join()
if self.pin_memory:
self.pin_memory_thread.join()
def _shutdown_workers(self):
if not self.shutdown:
self.shutdown = True
# removes pids from the C side data structure first so worker
# termination afterwards won't trigger false positive error report.
if self.worker_pids_set:
_remove_worker_pids(id(self))
self.worker_pids_set = False
self.done_event.set()
if self.pin_memory:
# Sending `None` to `pin_memory_thread` must be before
# stopping worker processes because the workers may leave
# corrupted data in `worker_result_queue`, causing
# `pin_memory_thread` unable to read and terminate properly.
self.worker_result_queue.put(None)
# Workers can't be waiting to put be cause their output queue
# is a multiprocessing.Queue and its .put is non-blocking.
# They can only be waiting to get, so we put `None` here.
for _w in self.workers:
# Putting as many None as workers to ensure worker will get one
self.batch_queue.put(None)
for w in self.workers:
w.join()
if self.pin_memory:
self.pin_memory_thread.join()
def _shutdown_workers(self):
# Called when shutting down this `_MultiProcessingDataLoaderIter`.
# See NOTE [ Data Loader Multiprocessing Shutdown Logic ] for details on
# the logic of this function.
python_exit_status = torch_data_utils.python_exit_status
if python_exit_status is True or python_exit_status is None:
# See (2) of the note. If Python is shutting down, do no-op.
return
# Normal exit when last reference is gone / iterator is depleted.
# See (1) and the second half of the note.
if not self._shutdown:
self._shutdown = True
try:
# Exit `pin_memory_thread` first because exiting workers may leave
# corrupted data in `worker_result_queue` which `pin_memory_thread`
# reads from.
if hasattr(self, '_pin_memory_thread'):
# Use hasattr in case error happens before we set the attribute.
self._pin_memory_thread_done_event.set()
# Send something to pin_memory_thread in case it is waiting
# so that it can wake up and check `pin_memory_thread_done_event`
for worker_id in range(len(self._workers)):
self._worker_result_queues[worker_id].put((None, None))
self._pin_memory_thread.join()
for worker_id in range(len(self._workers)):
self._worker_result_queues[
worker_id].cancel_join_thread()
self._worker_result_queues[worker_id].close()
# Exit workers now.
self._workers_done_event.set()
for worker_id in range(len(self._workers)):
# Get number of workers from `len(self._workers)` instead of
# `self.num_workers` in case we error before starting all
# workers.
if self._worker_is_active[worker_id]:
self._shutdown_worker(worker_id)
for w in self._workers:
w.join()
for q in self._task_queues:
q.cancel_join_thread()
q.close()
finally:
# Even though all this function does is putting into queues that
# we have called `cancel_join_thread` on, weird things can
# happen when a worker is killed by a signal, e.g., hanging in
# `Event.set()`. So we need to guard this with SIGCHLD handler,
# and remove pids from the C side data structure only at the
# end.
#
# FIXME: Unfortunately, for Windows, we are missing a worker
# error detection mechanism here in this function, as it
# doesn't provide a SIGCHLD handler.
if self._worker_pids_set:
signal_handling._remove_worker_pids(id(self))
self._worker_pids_set = False