> Windows does allow you to reserve address space without committing it, but it then requires you to commit the chunks before you use them (see VirtualAlloc + M

> Windows does allow you to reserve address space without committing it, but it then requires you to commit the chunks before you use them (see VirtualAlloc + MEM_RESERVE) Personally, I think this is the right approach. Because you shouldn't have to decide between memory overcommit (which can fail badly in some reasonable scenarios) or "having to reserve all allocated address space of all processes in swap", which is way too pessimistic and would start causing unnecessary memory allocation failures in many reasonable scenarios. And I also think that even if you decide to support memory overcommit, it should be done per-process (at least), not at the whole system level like Linux is doing.