Re: [patch -rt 2/2] KVM: lapic: mark LAPIC timer handler as irqsafe

Marcelo Tosatti
2014-12-05T16:17:01Z

On Thu, Dec 04, 2014 at 02:53:26PM +0100, Paolo Bonzini wrote:
>
>
> On 25/11/2014 21:24, Thomas Gleixner wrote:
> > On Tue, 25 Nov 2014, Rik van Riel wrote:
> >> On 11/25/2014 12:21 PM, Marcelo Tosatti wrote:
> >>> Since lapic timer handler only wakes up a simple waitqueue,
> >>> it can be executed from hardirq context.
> >>>
> >>> Reduces average cyclictest latency by 3us.
> >>
> >> Can this patch be merged in the KVM tree, and go
> >> upstream via Paolo?
> >
> > Not really as it has RT dependencies ....
>
> Can hrtimer_start_expires even return ETIME on a non-RT kernel? If yes,
> I can take patch 2. If not, it's better to keep both patches in the RT
> tree.
>
> Paolo

It can't. We're still evaluating the necessity of this patch, will
resubmit accordingly.