Re: static scheduling - SCHED_IDLE?

Rik van Riel
2001-03-10T14:09:36Z

On Fri, 9 Mar 2001, Jamie Lokier wrote:
> Rik van Riel wrote:
> > > Just raise the priority whenever the task's in kernel mode. Problem
> > > solved.
> >
> > Remember that a task schedules itself out at the timer interrupt,
> > in kernel/sched.c::schedule() ... which is kernel mode ;)
>
> Even nicer. On x86 change this:
>
> reschedule:
> call SYMBOL_NAME(schedule) # test
> jmp ret_from_sys_call
>
> to this:
>
> reschedule:
> orl $PF_HONOUR_LOW_PRIORITY,flags(%ebx)
> call SYMBOL_NAME(schedule) # test
> andl $~PF_HONOUR_LOW_PRIORITY,flags(%ebx)
> jmp ret_from_sys_call

Wonderful !

I think we'll want to use this, since we can use it for:

1. SCHED_IDLE
2. load control, when the VM starts thrashing we can just
suspend a few processes to make sure the system as a
whole won't thrash to death
3. ... ?

regards,

Rik
--
Linux MM bugzilla: http://linux-mm.org/bugzilla.shtml

Virtual memory is like a game you can't win;
However, without VM there's truly nothing to lose...

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