[$] Dynamically sizing the kernel stack

The kernel stack is a scarce and tightly constrained resource; kerneldevelopers often have to go far out of their way to avoid using too muchstack space. The size of the stack is also fixed, leading to situationswhere it is too small for some code paths, while wastefully large forothers. At the 2024 Linux Storage,Filesystem, Memory Management, and BPF Summit, Pasha Tatashin proposedmaking the kernel stack size dynamic, making more space available whenneeded while saving memory overall. This change is not as easy toimplement as it might seem, though.