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

To: "Tristan Gingold" <Tristan.Gingold@xxxxxxxx>, <xen-ia64-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-ia64-devel] context switch bug ?
From: "Magenheimer, Dan (HP Labs Fort Collins)" <dan.magenheimer@xxxxxx>
Date: Mon, 26 Sep 2005 12:38:18 -0700
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Thread-topic: [Xen-ia64-devel] context switch bug ?
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? 

> -----Original Message-----
> From: xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx 
> [mailto:xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf 
> Of Tristan Gingold
> Sent: Monday, September 26, 2005 10:50 AM
> To: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
> Subject: [Xen-ia64-devel] context switch bug ?
> 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!
> Thanks.
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