Hi Barry
Thank you for your interest in my proposal. Let me try to answer your
question. You wrote:
To make the code avoid COW you would need to be able to make sure that all
> code memory blocks are not mixed in with PyObject memory blocks.
>
> Then the ref count dance will have trigger COW for the code.
The relevant parts of my proposal are (emphasis added)
When a Python function is called, the interpreter increases the refcount of
> its code object. At the end of the function's execution, the interpreter
> decreases the refcount. (An example below shows this.)
>
> **If Python were extended to take advantage of permanent code objects**,
> then for example popular code objects could be loaded into memory in this
> way. This can reduce memory usage (by sharing immutable resources) and
> reduce startup time.
I wanted this to mean that if the interpreter needs access to a permanent
code object, it simply accesses it, without changing any reference counts.
For this reason, permanent code objects don't need a refcount field. And
without that field, there is no refcount dance.
The interpreter has privileged access to permanent code objects (just as it
has to its own internals, unless deliberately exposed).
However, the code that is being interpreted has no such access. To enable
something like
>>> fn.__code__.co_code
b'whatever-the-bytecodes-are'
Python must have fn.__code__ return something that DOES have a refcount
field. It could be some sort of proxy object. Or it could be a 'transient
copy' of the permanent code object.
I tried to explain this in the Appendix, perhaps not well enough. I hope
this helps.
--
Jonathan
_______________________________________________
Python-ideas mailing list -- python-ideas@python.org
To unsubscribe send an email to python-ideas-le...@python.org
https://mail.python.org/mailman3/lists/python-ideas.python.org/
Message archived at
https://mail.python.org/archives/list/python-ideas@python.org/message/MTTSQNRZTLPLQKC2JDROY3S6VQW2VW3R/
Code of Conduct: http://python.org/psf/codeofconduct/
