On Sun, Apr 17, 2022, 3:59 AM Jin-oh Kang <jinoh.kang.kr@gmail.com> wrote:

On Tue, Apr 12, 2022, 5:59 PM Paul Gofman <pgofman@codeweavers.com> wrote:

I don’t think this complication worth it. What we would like to save is address space on 32 bit, but we can’t (before running 32 on 64 of course where this stack will be on 64 only). We apparently need to reserve address space for stack at once, so it has the space to grow, and then growing would only mean saving committed pages.

Maybe allocate extra stack only for function calls that might need it? Something like this: https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/ntddk/nf-ntddk-keexpandkernelstackandcallout

There's also https://github.com/gcc-mirror/gcc/blob/master/libgcc/config/i386/morestack.S, which is used by gcc -fsplit-stack, but we might need something more portable.

Will that work with existing host libraries which actually use the stack and are supposed to be be compatible with this split stack mechanics if we do something like that?