I am using it a euphemism for reserving address space and then committing pages as your list grows. This isn't preallocating memory, just address space.
But pool allocation works as well. The idea is to go from a chonky representation to a portable compact representation of a C-struct but still have the Python accessors to this data look idiomatic.
In what sense is reserving address space not "preallocating memory"? It might not be allocated to an object, but it certainly is allocated to your process... yes?
No address space does not mean you have memory, you can reserve gigabytes of address space and your process will still show nothing allocated until you commit it.
The term isn't familiar to me, and when I try to look it up I get almost exclusively Rust-related results. I guess you mean https://en.wikipedia.org/wiki/Region-based_memory_management , which I grew up calling "pool allocation".