I didn't see this until now, the problem is that when you spawn a new thread space for the stack needs to be allocated. Since the stack can't be reallocated eas

I didn't see this until now, the problem is that when you spawn a new thread space for the stack needs to be allocated. Since the stack can't be reallocated easily in C/C++ it also needs to be "big enough". The current implementation is to allocate several megabytes of stack for each thread, since memory accounting isn't strict this doesn't create problems because unused stack doesn't really take up space. If you start accounting memory you will also have to be stricter with allocating stacks for new threads, limiting yourself to just a page or two wherever possible. This is not an easy task.