Issue 23291: Documentation about Py_Finalize(): Freeing objects

➜

This issue tracker has been migrated to GitHub, and is currently read-only.
For more information, see the GitHub FAQs in the Python's Developer Guide.

This issue has been migrated to GitHub: https://github.com/python/cpython/issues/67480

classification

Title:	Documentation about Py_Finalize(): Freeing objects
Type:		Stage:
Components:	Documentation, Interpreter Core	Versions:	Python 3.11, Python 3.10, Python 3.9

process

Status:	open	Resolution:
Dependencies:		Superseder:
Assigned To:	docs@python	Nosy List:	Albert.Zeyer, docs@python, iritkatriel, vstinner
Priority:	normal	Keywords:

Created on 2015-01-21 17:53 by Albert.Zeyer, last changed 2022-04-11 14:58 by admin.

Messages (1)
msg234441 - (view)	Author: Albert Zeyer (Albert.Zeyer) *	Date: 2015-01-21 17:53
The documentation about Py_Finalize() about freeing objects is not exactly clear. Esp., when I have called Py_INCREF somewhere, those objects will always have ob_refcnt > 0 unless I call Py_DECREF somewhere, what about these objects? Will they be freed in Py_Finalize() or not? If not, what can I do? I guess calling Py_DECREF after Py_Finalize() is not allowed. I studied the Py_Finalize() code but I'm not exactly sure. It looks like such objects would not get freed (unless some implicit magic is happening somewhere). The comment about the last commented-out PyGC_Collect() call is also insightful and somewhat unsatisfying. Maybe PyObject_Free() still works, although that would not free any further referenced objects, I guess. Also, I'm not exactly sure about the pymalloc arenas. With pymalloc, maybe we could just free all pymalloc arenas and it would free all memory allocated by Python objects? Of course, that would not call any advanced tp_dealloc functions which might be important to be called, but we would never ever call those anyway anymore, or would we (how?)? So, maybe it would be good to do that?

msg234441 - (view)

Author: Albert Zeyer (Albert.Zeyer) *

Date: 2015-01-21 17:53

The documentation about Py_Finalize() about freeing objects is not exactly clear.

Esp., when I have called Py_INCREF somewhere, those objects will always have ob_refcnt > 0 unless I call Py_DECREF somewhere, what about these objects? Will they be freed in Py_Finalize() or not? If not, what can I do? I guess calling Py_DECREF after Py_Finalize() is not allowed.

I studied the Py_Finalize() code but I'm not exactly sure. It looks like such objects would not get freed (unless some implicit magic is happening somewhere). The comment about the last commented-out PyGC_Collect() call is also insightful and somewhat unsatisfying.

Maybe PyObject_Free() still works, although that would not free any further referenced objects, I guess. Also, I'm not exactly sure about the pymalloc arenas.

With pymalloc, maybe we could just free all pymalloc arenas and it would free all memory allocated by Python objects? Of course, that would not call any advanced tp_dealloc functions which might be important to be called, but we would never ever call those anyway anymore, or would we (how?)?
So, maybe it would be good to do that?

History
Date	User	Action	Args
2022-04-11 14:58:12	admin	set	github: 67480
2022-01-28 19:43:34	iritkatriel	set	nosy: + iritkatriel, docs@python, vstinner assignee: docs@python components: + Documentation versions: + Python 3.9, Python 3.10, Python 3.11, - Python 2.7
2015-01-21 17:53:44	Albert.Zeyer	create