[nostrademons]

Only the portions of the stack that are actually touched trigger a TLB miss and page fault. If you've got a million threads but each only touches the first 4K of stack space, you end up only touching 4G of RAM even though you've mapped 1T of it.

[cryptonector]

When you have terabytes of RAM you want large pages anyways.

[gpderetta]

As each stack will need to use [1] at least one page of physical memory, large pages are not great for stacks as they will normally waste memory.

[1] for classic contiguous stacks of course. That doesn't apply for separately allocated frames or segmented stacks.