> If we knew in advance which thread would need extra contiguous memory for deep recursion using variables of automatic storage duration we could allocates its

> If we knew in advance which thread would need extra contiguous memory for deep recursion using variables of automatic storage duration we could allocates its stack at an address with enough space left. And this is a real option. While determining the maximum stack size of an arbitrary program is halting-problem-equivalent (requires determining the maximum depth of the runtime call graph), we can trivially choose to write code where determining the maximum stack size is also trivial. This static analysis is commonly done on embedded systems, and essentially comes down to "don't write code that you can't guarantee the correctness of", which should be starting stakes anyhow.