diff options
| -rw-r--r-- | Lib/multiprocessing/util.py | 5 | ||||
| -rw-r--r-- | Lib/test/test_multiprocessing.py | 32 | ||||
| -rw-r--r-- | Misc/NEWS | 3 |
3 files changed, 38 insertions, 2 deletions
diff --git a/Lib/multiprocessing/util.py b/Lib/multiprocessing/util.py index 72385a8..f5862b4 100644 --- a/Lib/multiprocessing/util.py +++ b/Lib/multiprocessing/util.py @@ -322,10 +322,13 @@ atexit.register(_exit_function) class ForkAwareThreadLock(object): def __init__(self): + self._reset() + register_after_fork(self, ForkAwareThreadLock._reset) + + def _reset(self): self._lock = threading.Lock() self.acquire = self._lock.acquire self.release = self._lock.release - register_after_fork(self, ForkAwareThreadLock.__init__) class ForkAwareLocal(threading.local): def __init__(self): diff --git a/Lib/test/test_multiprocessing.py b/Lib/test/test_multiprocessing.py index 14ec61c..9b3e180 100644 --- a/Lib/test/test_multiprocessing.py +++ b/Lib/test/test_multiprocessing.py @@ -3432,12 +3432,42 @@ class TestNoForkBomb(unittest.TestCase): self.assertEqual('', err.decode('ascii')) # +# Issue #17555: ForkAwareThreadLock +# + +class TestForkAwareThreadLock(unittest.TestCase): + # We recurisvely start processes. Issue #17555 meant that the + # after fork registry would get duplicate entries for the same + # lock. The size of the registry at generation n was ~2**n. + + @classmethod + def child(cls, n, conn): + if n > 1: + p = multiprocessing.Process(target=cls.child, args=(n-1, conn)) + p.start() + p.join() + else: + conn.send(len(util._afterfork_registry)) + conn.close() + + def test_lock(self): + r, w = multiprocessing.Pipe(False) + l = util.ForkAwareThreadLock() + old_size = len(util._afterfork_registry) + p = multiprocessing.Process(target=self.child, args=(5, w)) + p.start() + new_size = r.recv() + p.join() + self.assertLessEqual(new_size, old_size) + +# # # testcases_other = [OtherTest, TestInvalidHandle, TestInitializers, TestStdinBadfiledescriptor, TestWait, TestInvalidFamily, - TestFlags, TestTimeouts, TestNoForkBomb] + TestFlags, TestTimeouts, TestNoForkBomb, + TestForkAwareThreadLock] # # @@ -29,6 +29,9 @@ Core and Builtins Library ------- +- Issue #17555: Fix ForkAwareThreadLock so that size of after fork + registry does not grow exponentially with generation of process. + - Issue #17707: multiprocessing.Queue's get() method does not block for short timeouts. |