[Python-Dev] Python initialization and embedded Python

[Eric Snow]

On Mon, Nov 20, 2017 at 3:03 PM, Victor Stinner
<victor.stinner at gmail.com> wrote:
> To statically initialize PyMemAllocatorEx fields, you need to export a
> lot of allocator functions. I would prefer to not do that.
>
> [snip]
>
> The rules to choose the allocator to each domain are also complex
> depending if pymalloc is enabled, debug hooks are enabled by default,
> etc. The memory allocator is also linked to _PyMem_Debug which is not
> currently in Include/internals/ but Objects/obmalloc.c.

I'm not suggesting supporting the full machinery.  Rather, as my PR
demonstrates, we can statically initialize the minimum needed to
support pre-init use of PyMem_RawMalloc() and PyMem_RawFree().  The
allocators will be fully initialized once the runtime is initialized
(i.e. once Py_Initialize() is called), just as they are now.

FWIW, I'm not sure that's the best approach.  See my notes in
https://bugs.python.org/issue32096.

>
> I understand that moving global variables to _PyRuntime helps to
> clarify how these variables are initialized and then finalized, but
> memory allocators are a complex corner case.

Agreed.  I spent a large portion of my time getting the allocators
right when working on the original _PyRuntime patch.  It's tricky
code.

-eric