kernel threads as threads.

[David Xu]

Julian Elischer wrote:

>
> I have made a first set of changes to allow threads to be 'forked' 
> within the kernel.
>
> I have run on the resulting kernel for some of today with no problems 
> other than
> some statistics oddness in top which I plan on looking at next week.
>
> The current patch doen't remove the ability to make kernel processes, 
> however it does
> add the ability to make threads under process 0 and alters nearly all 
> the users of
> kernel threads to actually do this.. The exception is the aio threads, 
> as they seem to require
> separate address spaces to work with and that requires separate proc 
> structures.
>
> I was thinking that they could act as extra threads on the calling 
> processes but that
> is more of a rewrite than I plan right now.
>
> Anyhow the diffs so far are at:
>
> http://www.freebsd.org/~julian/kthread.diff.
>
> more later.
>
> julian

in vfs_aio.c, we have to borrow user process's vmspace,  creating all 
kthread in
proc0 breaks this.

David Xu