Re: [PATCH v2 2/4] powerpc/spinlock: support vcpu preempted check

[xinhui]

On 2016å07æ06æ 16:32, Wanpeng Li wrote:
> 2016-07-06 15:58 GMT+08:00 Peter Zijlstra <peterz@xxxxxxxxxxxxx>:
> > On Wed, Jul 06, 2016 at 02:46:34PM +0800, Wanpeng Li wrote:
> > > > SO it's easy for ppc to implement such interface. Note that yield_count is
> > > > set by powerVM/KVM.
> > > > and only pSeries can run a guest for now. :)
> > > >
> > > > I also review x86 related code, looks like we need add one hyer-call to get
> > > > such vcpu preemption info?
> > >
> > > There is no such stuff to record lock holder in x86 kvm, maybe we
> > > don't need to depend on PLE handler algorithm to guess it if we can
> > > know lock holder vCPU directly.
> >
> > x86/kvm has vcpu->preempted to indicate if a vcpu is currently preempted
> > or not. I'm just not sure if that is visible to the guest or how to make
> > it so.
>
> Yeah, I miss it. I can be the volunteer to do it if there is any idea,
> ping Paolo. :)
glad to know that. :)


> Regards,
> Wanpeng Li