Re: Weightless process class

Rik van Riel (riel@conectiva.com.br)
Wed, 4 Oct 2000 17:34:55 -0300 (BRST)

On Wed, 4 Oct 2000, Nathan Paul Simons wrote:
> On Wed, Oct 04, 2000 at 04:16:22PM -0300, Rik van Riel wrote:
> > Do we have something like an in_kernel(proc) macro ???
>
> "user_mode()" in include/asm/ptrace.h? But that only checks to
> see if the regs struct you passed it are from a kernel thread or
> not. No checks to see if the process has any kernel locks.

A process can't grab a kernel lock and then switch
back to user mode, can it? (if it could, I can
imagine some nasty DoS attacks...)

Problem is, when we decide to schedule in a process
or not, we know the process was last stuck in
schedule() ... in kernel mode ;(

I'd love to be proven wrong though ... this would be
some extremely useful functionality ;)

regards,

Rik

--
"What you're running that piece of shit Gnome?!?!"
       -- Miguel de Icaza, UKUUG 2000


http://www.conectiva.com/		http://www.surriel.com/


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