I remember Jason Thorpe speaking a while back about having the VM mechanisms
available to do an implementation of clone() or rfork() (not necessarily
threading, but `splitting a process').

As it turns out, Wine (which I pretty much need for work... <sigh>) now
requires some sort of syscall in the kernel to do this sort of work,
otherwise the real preemptive multitasking of Win32 doesn't work, and hence
Wine can only run Win16 apps.  It doesn't use pthread et. al. because it
needs some low level control (over things like the LDT).

Now, O*BSD implemented rfork() over Mach VM, so certainly this shouldn't be
impossible on UVM?

-- 
-- Todd Vierling (Personal tv@pobox.com; Bus. todd_vierling@xn.xerox.com)