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

xinhui xinhui.pan at linux.vnet.ibm.com
Wed Jul 6 20:18:27 AEST 2016

On 2016年07月06日 16:32, Wanpeng Li wrote:
> 2016-07-06 15:58 GMT+08:00 Peter Zijlstra <peterz at infradead.org>:
>> 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

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