diff options
Diffstat (limited to 'Lib/multiprocessing/forking.py')
| -rw-r--r-- | Lib/multiprocessing/forking.py | 40 |
1 files changed, 25 insertions, 15 deletions
diff --git a/Lib/multiprocessing/forking.py b/Lib/multiprocessing/forking.py index cc7c326..a2c61ef 100644 --- a/Lib/multiprocessing/forking.py +++ b/Lib/multiprocessing/forking.py @@ -35,6 +35,7 @@ import os import sys import signal +import select from multiprocessing import util, process @@ -101,10 +102,12 @@ else: if sys.platform != 'win32': import time + import select exit = os._exit duplicate = os.dup close = os.close + _select = util._eintr_retry(select.select) # # We define a Popen class similar to the one from subprocess, but @@ -118,8 +121,12 @@ if sys.platform != 'win32': sys.stderr.flush() self.returncode = None + r, w = os.pipe() + self.sentinel = r + self.pid = os.fork() if self.pid == 0: + os.close(r) if 'random' in sys.modules: import random random.seed() @@ -128,6 +135,11 @@ if sys.platform != 'win32': sys.stderr.flush() os._exit(code) + # `w` will be closed when the child exits, at which point `r` + # will become ready for reading (using e.g. select()). + os.close(w) + util.Finalize(self, os.close, (r,)) + def poll(self, flag=os.WNOHANG): if self.returncode is None: try: @@ -145,20 +157,14 @@ if sys.platform != 'win32': return self.returncode def wait(self, timeout=None): - if timeout is None: - return self.poll(0) - deadline = time.time() + timeout - delay = 0.0005 - while 1: - res = self.poll() - if res is not None: - break - remaining = deadline - time.time() - if remaining <= 0: - break - delay = min(delay * 2, remaining, 0.05) - time.sleep(delay) - return res + if self.returncode is None: + if timeout is not None: + r = _select([self.sentinel], [], [], timeout)[0] + if not r: + return None + # This shouldn't block if select() returned successfully. + return self.poll(os.WNOHANG if timeout == 0.0 else 0) + return self.returncode def terminate(self): if self.returncode is None: @@ -183,7 +189,7 @@ else: import time from pickle import dump, load, HIGHEST_PROTOCOL - from _multiprocessing import win32, Connection, PipeConnection + from _multiprocessing import win32 from .util import Finalize def dump(obj, file, protocol=None): @@ -258,6 +264,7 @@ else: self.pid = pid self.returncode = None self._handle = hp + self.sentinel = int(hp) # send information to child prep_data = get_preparation_data(process_obj._name) @@ -411,6 +418,9 @@ else: # Make (Pipe)Connection picklable # + # Late import because of circular import + from .connection import Connection, PipeConnection + def reduce_connection(conn): if not Popen.thread_is_spawning(): raise RuntimeError( |