> And I understood that Dino proposed to share one code instance as a memory mapped file for *all* processes.

What instance means?  code object? co_code?
Anyway, Dino didn't propose such thing.  He only proposed accepting buffer object for code constructor.
He didn't describe how to use buffer object.  Python doesn't provide share buffer object inter processes.

There are no enough concrete information for estimate benefits.
We're discussing imagination, not concrete idea.

Let's stop discuss more, and wait Dino provide concrete example which can be used to estimate benefits.