Thanks for your comments! :-) But I still don't understand...
I'm not proposing to swap out kernel stack pages. Instead, I'm wondering why it isn't possible
to just allocate additional memory pages for the stack the moment a page fault happens because
the currently allocated stack overflows.
This assumes that it is possible to just map in additional pages. Why does the stack have to
be in contiguous memory - is it addressed via its physical address?
If so, is the cost of setting up virtual page mapping too high? The event that new stack pages
would have to be allocated would be very rare, so it wouldn't have to be fast...