New submission from Eric Snow <ericsnowcurren...@gmail.com>:
In order to keep subinterpreters properly isolated, objects
from one interpreter should not be used in C-API calls in
another interpreter. That is relatively straight-forward
except in one case: indicating that the other interpreter
doesn't need the object to exist any more (similar to
PyBuffer_Release() but more general). I consider the
following solutions to be the most viable. Both make use
of recounts to protect cross-interpreter usage (with incref
before sharing).
1. manually switch interpreters (new private function)
a. acquire the GIL
b. if refcount > 1 then decref and release the GIL
c. switch
d. new thread (or re-use dedicated one)
e. decref
f. kill thread
g. switch back
h. release the GIL
2. change pending call mechanism (see Py_AddPendingCall) to
per-interpreter instead of global (add "interp" arg to
signature of new private C-API function)
a. queue a function that decrefs the object
3. new cross-interpreter-specific private C-API function
a. queue the object for decref (a la Py_AddPendingCall)
in owning interpreter
I favor #2, since it is more generally applicable. #3 would
probably be built on #2 anyway. #1 is relatively inefficient.
With #2, Py_AddPendingCall() would become a simple wrapper
around the new private function.
----------
messages: 317333
nosy: eric.snow, ncoghlan, serhiy.storchaka, vstinner, yselivanov
priority: normal
severity: normal
stage: needs patch
status: open
title: Add a cross-interpreter-safe mechanism to indicate that an object may be
destroyed.
versions: Python 3.4
_______________________________________
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue33608>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe:
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
