Re: [patch 13/26] Xen-paravirt_ops: Consistently wrap paravirt opscallsites to make them patchable

[Zachary Amsden]

Jeremy Fitzhardinge wrote:
> Zachary Amsden wrote:
>   
> > I think Jeremy's idea was to have interrupt handlers leave interrupts
> > disabled on exit if pda.intr_mask was set.  In which case, they would
> > bypass all work and we could never get preempted.
> >     
>
> Yes, I was worried that if we left the isr without actually handling the
> interrupt, it would still be asserted and we'd just get interrupted
> again.  The idea is that we avoid touching cli/sti for the common case
> of no interrupts while interrupts are disabled, but we'd still need to
> fall back to using them if an interrupt becomes pending.
>
>   
> > I don't think leaving hardware interrupts disabled for such a long
> > time is good though. 
> >     
>
> How long?  It would be no longer than now, and possibly less, wouldn't it?
>   

Hmm.  Perhaps.  Something about the asymmetry bothers me alot though.

Zach

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