The multiprocessing.resource_tracker replaces the multiprocessing.semaphore_tracker module. Other than semaphores, resource_tracker also tracks shared_memory segments. Patch by Pierre Glaser.
Deprecated passing the following arguments as keyword arguments:
- "func" in functools.partialmethod(), weakref.finalize(),
profile.Profile.runcall(), cProfile.Profile.runcall(),
bdb.Bdb.runcall(), trace.Trace.runfunc() and
curses.wrapper().
- "function" in unittest.addModuleCleanup() and
unittest.TestCase.addCleanup().
- "fn" in the submit() method of concurrent.futures.ThreadPoolExecutor
and concurrent.futures.ProcessPoolExecutor.
- "callback" in contextlib.ExitStack.callback(),
contextlib.AsyncExitStack.callback() and
contextlib.AsyncExitStack.push_async_callback().
- "c" and "typeid" in the create() method of multiprocessing.managers.Server
and multiprocessing.managers.SharedMemoryServer.
- "obj" in weakref.finalize().
Also allowed to pass arbitrary keyword arguments (even "self" and "func")
if the above arguments are passed as positional argument.
* bpo-35493: Use Process.sentinel instead of sleeping for polling worker status in multiprocessing.Pool
* Use self-pipe pattern to avoid polling for changes
* Refactor some variable names and add comments
* Restore timeout and poll
* Use reader object only on wait()
* Recompute worker sentinels every time
* Remove timeout and use change notifier
* Refactor some methods to be overloaded by the ThreadPool, document the cache class and fix typos
* Added tests for shared_memory submodule.
* Added tests for ShareableList.
* Fix bug in allocationn size during creation of empty ShareableList illuminated by existing test run on Linux.
* Initial set of docs for shared_memory module.
* Added docs for ShareableList, added doctree entry for shared_memory submodule, name refactoring for greater clarity.
* Added examples to SharedMemoryManager docs, for ease of documentation switched away from exclusively registered functions to some explicit methods on SharedMemoryManager.
* Wording tweaks to docs.
* Fix test failures on Windows.
* Added tests around SharedMemoryManager.
* Documentation tweaks.
* Fix inappropriate test on Windows.
* Further documentation tweaks.
* Fix bare exception.
* Removed __copyright__.
* Fixed typo in doc, removed comment.
* Updated SharedMemoryManager preliminary tests to reflect change of not supporting all registered functions on SyncManager.
* Added Sphinx doctest run controls.
* CloseHandle should be in a finally block in case MapViewOfFile fails.
* Missed opportunity to use with statement.
* Switch to self.addCleanup to spare long try/finally blocks and save one indentation, change to use decorator to skip test instead.
* Simplify the posixshmem extension module.
Provide shm_open() and shm_unlink() functions. Move other
functionality into the shared_memory.py module.
* Added to doc around size parameter of SharedMemory.
* Changed PosixSharedMemory.size to use os.fstat.
* Change SharedMemory.buf to a read-only property as well as NamedSharedMemory.size.
* Marked as provisional per PEP411 in docstring.
* Changed SharedMemoryTracker to be private.
* Removed registered Proxy Objects from SharedMemoryManager.
* Removed shareable_wrap().
* Removed shareable_wrap() and dangling references to it.
* For consistency added __reduce__ to key classes.
* Fix for potential race condition on Windows for O_CREX.
* Remove unused imports.
* Update access to kernel32 on Windows per feedback from eryksun.
* Moved kernel32 calls to _winapi.
* Removed ShareableList.copy as redundant.
* Changes to _winapi use from eryksun feedback.
* Adopt simpler SharedMemory API, collapsing PosixSharedMemory and WindowsNamedSharedMemory into one.
* Fix missing docstring on class, add test for ignoring size when attaching.
* Moved SharedMemoryManager to managers module, tweak to fragile test.
* Tweak to exception in OpenFileMapping suggested by eryksun.
* Mark a few dangling bits as private as suggested by Giampaolo.
Changes in this commit:
1. Use a _strong_ reference between the Pool and associated iterators
2. Rework PR #8450 to eliminate a cycle in the Pool.
There is no test in this commit because any test that automatically tests this behaviour needs to eliminate the pool before joining the pool to check that the pool object is garbaged collected/does not hang. But doing this will potentially leak threads and processes (see https://bugs.python.org/issue35413).
Fix a reference issue inside multiprocessing.Pool that caused the pool to remain alive if it was deleted without being closed or terminated explicitly.
After some failures in AMD64 FreeBSD CURRENT Debug 3.x buildbots
regarding tests in test_multiprocessing_spawn and after examining
similar failures in test_socket, some errors in the calculation of
ancillary data buffers were found in multiprocessing.reduction.
CMSG_LEN() can often be used as the buffer size for recvmsg() to
receive a single item of ancillary data, but RFC 3542 requires portable
applications to use CMSG_SPACE() and thus include space for padding,
even when the item will be the last in the buffer.
The failures we experience are due to the usage of CMSG_LEN() instead of
CMSG_SPACE().
Fail `test_semaphore_tracker_sigint` if no warnings are expected and one is received.
Fix race condition when the child receives SIGINT before it can register signal handlers for it.
The race condition occurs when the parent calls
`_semaphore_tracker.ensure_running()` (which in turn spawns the
semaphore_tracker using `_posixsubprocess.fork_exec`), the child
registers the signal handlers and the parent tries to kill the child.
What seem to happen is that in some slow systems, the parent sends the
signal to kill the child before the child protects against the signal.
Fix a race condition in Popen of
multiprocessing.popen_spawn_win32. The child process now duplicates
the read end of pipe instead of "stealing" it.
Previously, the read end of pipe was "stolen" by the child process,
but it leaked a handle if the child process had been terminated
before it could steal the handle from the parent process.
In some conditions the standard streams will be None or closed in the child process (for example if using "pythonw" instead of "python" on Windows). Avoid failing with a non-0 exit code in those conditions.
Report and initial patch by poxthegreat.
Fix deadlocks in :class:`concurrent.futures.ProcessPoolExecutor` when task arguments or results cause pickling or unpickling errors.
This should make sure that calls to the :class:`ProcessPoolExecutor` API always eventually return.
* bpo-31310: multiprocessing's semaphore tracker should be launched again if crashed
* Avoid mucking with process state in test.
Add a warning if the semaphore process died, as semaphores may then be leaked.
* Add NEWS entry
* bpo-31308: If multiprocessing's forkserver dies, launch it again when necessary.
* Fix test on Windows
* Add NEWS entry
* Adopt a different approach: ignore SIGINT and SIGTERM, as in semaphore tracker.
* Fix comment
* Make sure the test doesn't muck with process state
* Also test previously-started processes
* Update 2017-08-30-17-59-36.bpo-31308.KbexyC.rst
* Avoid masking SIGTERM in forkserver. It's not necessary and causes a race condition in test_many_processes.
* Make error message more informative
Replace assertions in error-reporting code with more-informative version that doesn't cause confusion over where and what the error is.
* Additional clarification + get travis to check
* Change from SystemError to TypeError
As suggested in PR comment by @pitrou, changing from SystemError; TypeError appears appropriate.
* NEWS file installation; ACKS addition (will do my best to justify it by additional work)
* Making current AssertionErrors in multiprocessing more informative
* Blurb added re multiprocessing managers.py, queues.py cleanup
* Further multiprocessing cleanup - went through pool.py
* Fix two asserts in multiprocessing/util.py
* Most asserts in multiprocessing more informative
* Didn't save right version
* Further work on multiprocessing error messages
* Correct typo
* Correct typo v2
* Blasted colon... serves me right for trying to work on two things at once
* Simplify NEWS entry
* Update 2017-08-18-17-16-38.bpo-5001.gwnthq.rst
* Update 2017-08-18-17-16-38.bpo-5001.gwnthq.rst
OK, never mind.
* Corrected (thanks to pitrou) error messages for notify
* Remove extraneous backslash in docstring.
* Make error message more informative
Replace assertions in error-reporting code with more-informative version that doesn't cause confusion over where and what the error is.
* Additional clarification + get travis to check
* Change from SystemError to TypeError
As suggested in PR comment by @pitrou, changing from SystemError; TypeError appears appropriate.
* NEWS file installation; ACKS addition (will do my best to justify it by additional work)
multiprocessing.Process.is_alive() now removes the process from the
_children set if the process completed.
The change prevents leaking "dangling" processes.
Pierre Glaser
Antoine Pitrou
Serhiy Storchaka
penguindustin
Thomas Moreau
Pablo Galindo
Davin Potts
Rémi Lapeyre
Steve Dower
Victor Stinner
Srinivas Thatiparthy (శ్రీనివాస్ తాటిపర్తి)
Alexander Buchkovsky
Julien Palard
Zackery Spytz
tzickel
Derek B. Kim
Antoine Pitrou
Allen W. Smith, Ph.D
Victor Stinner