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

Zachary Amsden
2007-03-21T00:14:21Z

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