Re: Q: behaviour of mlockall(MCL_FUTURE) and VM_GROWSDOWN segments

[Andi Kleen]

Andrew Morton <[e-mail]> writes:

> So in this case, the behaviour I would prefer is MCL_FUTURE for
> all vma's *except* the stack.   Stack pages should be locked
> only when they are faulted in.   Hard call.

There is just one problem: linuxthread stacks are just ordinary mappings
and they are in no way special to the kernel; they aren't VM_GROWSDOWN. 
You would need to add a way to the kernel first to tag the linux thread 
stacks in a way that is recognizable to mlockall and then do that 
from linuxthreads. 

I think for the normal stack - real VM_GROWSDOWN segments - mlockall
already does the right thing.

-Andi