Multiprocessing in Python isn't exactly like forking on other languages. There's no shared Python memory, it's just a new interpreter instance, and then you have to use sharing mechanisms (shared arrays/values, pipes, queues) to transfer data explicitly.
I know, but the entire point of CoW is you don't need shared memory, as long as the fork happens after the memory was written it'll just act like an entirely independent copy transparently to the application, with the OS duplicating the backing page on the first write.
Edit: Ah I see, you're saying the library itself discards anything created from python. That sounds like an implementation problem then, I'd expect it to at least keep imports so any static code pages don't need to be recreated (the interpreter itself should be fine at least, unless it's doing something really dumb).
