> Adding yet another API to allocate memory has a cost
Please don't FUD this one to death. Aligned memory access is sometimes important and we currently have no straight-forward way to achieve it. If you're truly worried about adding single new function to the public C API, we can create just a single internal function: void * _PyMem_RawMallocAligned(size_t size, size_t alignment).
> aligning every data structure on a cacheline boundary
> doesn't sound like a very good idea
We don't have to align EVERY data structure. But I do have immediate beneficial use cases for set tables and for data blocks in deque objects. I need this function and would appreciate your help in fitting it in nicely with the current memory management functions and macros.