Re: [Xen-ia64-devel] context switch bug ?

[Tristan Gingold <Tristan.Gingold@xxxxxxxx>]

Le Lundi 26 Septembre 2005 21:38, Magenheimer, Dan (HP Labs Fort Collins) a 
écrit :
> I'm not sure if I'm misunderstanding, but the line
> that is between context_switch and context_switch_finalize
> is spin_UNLOCK_irq, which releases the lock, correct?
Sure, but this is not run in the next domain, since a switch has just occured!

Tristan.

> > Hi,
> >
> > while working on SMP, I think I hit a problem which may
> > require a local
> > redesign in context switching.
> >
> > In common/schedule.c(__enter_scheduler), the last lines are:
> >
> >     context_switch(prev, next);
> >
> >     spin_unlock_irq(&schedule_data[cpu].schedule_lock);
> >
> >     context_switch_finalise(next);
> > }
> >
> > Unfortunatly, on ia64, context_switch does all the work and
> > context_switch_finalise does nothing.  Therefore, the cpu-spin lock is
> > still taken when the domain runs [even with one cpu].
> > It is correct ?
> >
> > I will try to fix this issue tomorrow, and I will look on x86
> > code.  However,
> > if anymore has already think about this issue, please share!


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