Notify huge and giant allocations through callback

Hi,

I am new to mimalloc, but I'm loving it already.

I read the mimalloc paper and I understand mimalloc purpose is to improve allocation performance for not too big allocations. I think it would be useful to be able to register a callback that notifies you when you have allocations considered huge and giant. I already tried this and it helped me find some places where we could use another allocator specific for those cases.

It would be even better if you could provide the memory for those allocations through the callback, although mimalloc would keep control of when to alloc and free. This could be like being able to extend mimalloc for huge and giant cases and it would be really nice in some applications.

What do you think?

Thanks.

The issue names no files, tests, or entry points. Begin by locating the huge and giant allocation paths in mimalloc and determine the callback and externally supplied memory semantics before proposing an API. Done would require an agreed design and corresponding implementation and tests.