Re: [Xen-devel] [PATCH v7 10/11] pvqspinlock, x86: Enable qspinlock PV support for KVM

[Waiman Long <waiman.long@xxxxxx>]

On 03/20/2014 06:07 PM, Paolo Bonzini wrote:
> Il 19/03/2014 21:14, Waiman Long ha scritto:
> > This patch adds the necessary KVM specific code to allow KVM to support
> > the sleeping and CPU kicking operations needed by the queue spinlock PV
> > code.
> The remaining problem of this patch is that you cannot get the 
> generically optimal configuration: qspinlock on baremetal, PV 
> qspinlock on KVM/Xen, unfair qspinlock on VMware/Hyper-V.  You really 
> need to disable unfair locks in kvm_spinlock_init.
> Paolo
So you are suggesting that it is not a good idea to have both unfair 
lock & PV be enabled together. Right?
In order to disable unfair locks in kvm_spinlock_init(), it has to run 
after the unfair lock init code. Do you guys know what determine the 
init function execution sequence?
-Longman

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