Re: 2.5.40-mm2

[Robert Love <rml@tech9.net>]

On Sun, 2002-10-06 at 18:07, Andrew Morton wrote:

> > -                       while (base->running_timer == timer) {
> > +                       while (base->running_timer == timer)
> >                                 cpu_relax();
> > -                               preempt_disable();
> > -                               preempt_enable();

I am confused as to why Ingo would put these here.  He knows very well
what he is doing... surely he had a reason.

If he intended to force a preemption point here, then the lines needs to
be reversed.  This assumes, of course, preemption is disabled here.  But
I do not think it is.

If he just wanted to check for preemption, we have a
preempt_check_resched() which does just that (I even think he wrote
it).  Note as long as interrupts are enabled this probably does not
achieve much anyhow.

So I do not know.  I find it odd the solution is to completely remove
it...

Btw, I think the solution to the crash is to add a check to
cpu_online().

	Robert Love