Re: static scheduling - SCHED_IDLE?

[Rik van Riel]

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
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