https://github.com/python/cpython/commit/fc4532a55d23887bae49350d2f939c597d6... commit: fc4532a55d23887bae49350d2f939c597d6b5b98 branch: 3.12 author: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> committer: ericsnowcurrently <ericsnowcurrently@gmail.com> date: 2023-07-31T17:25:18-06:00 summary: [3.12] gh-105766: Document that Custom Allocators Must Be Thread-Safe (gh-107519) (gh-107522) gh-105766: Document that Custom Allocators Must Be Thread-Safe (gh-107519) (cherry picked from commit db361a340af3970c279908c8746a6b9ed45f47b8) Co-authored-by: Eric Snow <ericsnowcurrently@gmail.com> files: M Doc/c-api/memory.rst M Doc/whatsnew/3.12.rst diff --git a/Doc/c-api/memory.rst b/Doc/c-api/memory.rst index 8968b26b64320..1df8c2b911ca8 100644 --- a/Doc/c-api/memory.rst +++ b/Doc/c-api/memory.rst @@ -476,6 +476,10 @@ Customize Memory Allocators thread-safe: the :term:`GIL <global interpreter lock>` is not held when the allocator is called. + For the remaining domains, the allocator must also be thread-safe: + the allocator may be called in different interpreters that do not + share a ``GIL``. + If the new allocator is not a hook (does not call the previous allocator), the :c:func:`PyMem_SetupDebugHooks` function must be called to reinstall the debug hooks on top on the new allocator. @@ -500,6 +504,8 @@ Customize Memory Allocators **must** wrap the existing allocator. Substituting the current allocator for some other arbitrary one is **not supported**. + .. versionchanged:: 3.12 + All allocators must be thread-safe. .. c:function:: void PyMem_SetupDebugHooks(void) diff --git a/Doc/whatsnew/3.12.rst b/Doc/whatsnew/3.12.rst index cbf47e4ad835d..39e702bb012fb 100644 --- a/Doc/whatsnew/3.12.rst +++ b/Doc/whatsnew/3.12.rst @@ -1922,6 +1922,13 @@ Porting to Python 3.12 * :c:func:`PyUnstable_Long_IsCompact` * :c:func:`PyUnstable_Long_CompactValue` +* Custom allocators, set via :c:func:`PyMem_SetAllocator`, are now + required to be thread-safe, regardless of memory domain. Allocators + that don't have their own state, including "hooks", are not affected. + If your custom allocator is not already thread-safe and you need + guidance then please create a new GitHub issue + and CC ``@ericsnowcurrently``. + Deprecated ----------