[Python-checkins] Revert "bpo-34172: multiprocessing.Pool leaks resources after being deleted (GH-8450)" (GH-10971)
Victor Stinner
webhook-mailer at python.org
Thu Dec 6 02:51:54 EST 2018
https://github.com/python/cpython/commit/9dfc754d61c55a526304e10a328bad448efa9ee9
commit: 9dfc754d61c55a526304e10a328bad448efa9ee9
branch: master
author: Victor Stinner <vstinner at redhat.com>
committer: GitHub <noreply at github.com>
date: 2018-12-06T08:51:47+01:00
summary:
Revert "bpo-34172: multiprocessing.Pool leaks resources after being deleted (GH-8450)" (GH-10971)
This reverts commit 97bfe8d3ebb0a54c8798f57555cb4152f9b2e1d0.
files:
D Misc/NEWS.d/next/Library/2018-07-26-10-31-52.bpo-34172.8ovLNi.rst
M Lib/multiprocessing/pool.py
M Lib/test/_test_multiprocessing.py
diff --git a/Lib/multiprocessing/pool.py b/Lib/multiprocessing/pool.py
index 7a6d01490146..2b3cc59a9ff8 100644
--- a/Lib/multiprocessing/pool.py
+++ b/Lib/multiprocessing/pool.py
@@ -149,9 +149,8 @@ class Pool(object):
'''
_wrap_exception = True
- @staticmethod
- def Process(ctx, *args, **kwds):
- return ctx.Process(*args, **kwds)
+ def Process(self, *args, **kwds):
+ return self._ctx.Process(*args, **kwds)
def __init__(self, processes=None, initializer=None, initargs=(),
maxtasksperchild=None, context=None):
@@ -186,15 +185,13 @@ def __init__(self, processes=None, initializer=None, initargs=(),
self._worker_handler = threading.Thread(
target=Pool._handle_workers,
- args=(self._cache, self._taskqueue, self._ctx, self.Process,
- self._processes, self._pool, self._inqueue, self._outqueue,
- self._initializer, self._initargs, self._maxtasksperchild,
- self._wrap_exception)
+ args=(self, )
)
self._worker_handler.daemon = True
self._worker_handler._state = RUN
self._worker_handler.start()
+
self._task_handler = threading.Thread(
target=Pool._handle_tasks,
args=(self._taskqueue, self._quick_put, self._outqueue,
@@ -220,62 +217,43 @@ def __init__(self, processes=None, initializer=None, initargs=(),
exitpriority=15
)
- @staticmethod
- def _join_exited_workers(pool):
+ def _join_exited_workers(self):
"""Cleanup after any worker processes which have exited due to reaching
their specified lifetime. Returns True if any workers were cleaned up.
"""
cleaned = False
- for i in reversed(range(len(pool))):
- worker = pool[i]
+ for i in reversed(range(len(self._pool))):
+ worker = self._pool[i]
if worker.exitcode is not None:
# worker exited
util.debug('cleaning up worker %d' % i)
worker.join()
cleaned = True
- del pool[i]
+ del self._pool[i]
return cleaned
def _repopulate_pool(self):
- return self._repopulate_pool_static(self._ctx, self.Process,
- self._processes,
- self._pool, self._inqueue,
- self._outqueue, self._initializer,
- self._initargs,
- self._maxtasksperchild,
- self._wrap_exception)
-
- @staticmethod
- def _repopulate_pool_static(ctx, Process, processes, pool, inqueue,
- outqueue, initializer, initargs,
- maxtasksperchild, wrap_exception):
"""Bring the number of pool processes up to the specified number,
for use after reaping workers which have exited.
"""
- for i in range(processes - len(pool)):
- w = Process(ctx, target=worker,
- args=(inqueue, outqueue,
- initializer,
- initargs, maxtasksperchild,
- wrap_exception)
- )
+ for i in range(self._processes - len(self._pool)):
+ w = self.Process(target=worker,
+ args=(self._inqueue, self._outqueue,
+ self._initializer,
+ self._initargs, self._maxtasksperchild,
+ self._wrap_exception)
+ )
w.name = w.name.replace('Process', 'PoolWorker')
w.daemon = True
w.start()
- pool.append(w)
+ self._pool.append(w)
util.debug('added worker')
- @staticmethod
- def _maintain_pool(ctx, Process, processes, pool, inqueue, outqueue,
- initializer, initargs, maxtasksperchild,
- wrap_exception):
+ def _maintain_pool(self):
"""Clean up any exited workers and start replacements for them.
"""
- if Pool._join_exited_workers(pool):
- Pool._repopulate_pool_static(ctx, Process, processes, pool,
- inqueue, outqueue, initializer,
- initargs, maxtasksperchild,
- wrap_exception)
+ if self._join_exited_workers():
+ self._repopulate_pool()
def _setup_queues(self):
self._inqueue = self._ctx.SimpleQueue()
@@ -433,20 +411,16 @@ def _map_async(self, func, iterable, mapper, chunksize=None, callback=None,
return result
@staticmethod
- def _handle_workers(cache, taskqueue, ctx, Process, processes, pool,
- inqueue, outqueue, initializer, initargs,
- maxtasksperchild, wrap_exception):
+ def _handle_workers(pool):
thread = threading.current_thread()
# Keep maintaining workers until the cache gets drained, unless the pool
# is terminated.
- while thread._state == RUN or (cache and thread._state != TERMINATE):
- Pool._maintain_pool(ctx, Process, processes, pool, inqueue,
- outqueue, initializer, initargs,
- maxtasksperchild, wrap_exception)
+ while thread._state == RUN or (pool._cache and thread._state != TERMINATE):
+ pool._maintain_pool()
time.sleep(0.1)
# send sentinel to stop workers
- taskqueue.put(None)
+ pool._taskqueue.put(None)
util.debug('worker handler exiting')
@staticmethod
@@ -828,7 +802,7 @@ class ThreadPool(Pool):
_wrap_exception = False
@staticmethod
- def Process(ctx, *args, **kwds):
+ def Process(*args, **kwds):
from .dummy import Process
return Process(*args, **kwds)
diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
index b62c119e9ae0..163419c30eba 100644
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -2558,13 +2558,6 @@ def test_release_task_refs(self):
# they were released too.
self.assertEqual(CountedObject.n_instances, 0)
- @support.reap_threads
- def test_del_pool(self):
- p = self.Pool(1)
- wr = weakref.ref(p)
- del p
- gc.collect()
- self.assertIsNone(wr())
def raising():
raise KeyError("key")
diff --git a/Misc/NEWS.d/next/Library/2018-07-26-10-31-52.bpo-34172.8ovLNi.rst b/Misc/NEWS.d/next/Library/2018-07-26-10-31-52.bpo-34172.8ovLNi.rst
deleted file mode 100644
index d1c5a7721019..000000000000
--- a/Misc/NEWS.d/next/Library/2018-07-26-10-31-52.bpo-34172.8ovLNi.rst
+++ /dev/null
@@ -1 +0,0 @@
-Fix a reference issue inside multiprocessing.Pool that caused the pool to remain alive if it was deleted without being closed or terminated explicitly.
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