On Fri, Sep 27, 2019 at 04:27:02PM +0800, Wanpeng Li wrote:
> From: Wanpeng Li <wanpen...@tencent.com>
> 
> Don't waste cycles to shrink/grow vCPU halt_poll_ns if host 
> side polling is disabled.
> 
> Cc: Marcelo Tosatti <mtosa...@redhat.com>
> Signed-off-by: Wanpeng Li <wanpen...@tencent.com>
> ---
>  virt/kvm/kvm_main.c | 28 +++++++++++++++-------------
>  1 file changed, 15 insertions(+), 13 deletions(-)
> 
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index e6de315..b368be4 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -2359,20 +2359,22 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
>       kvm_arch_vcpu_unblocking(vcpu);
>       block_ns = ktime_to_ns(cur) - ktime_to_ns(start);
>  
> -     if (!vcpu_valid_wakeup(vcpu))
> -             shrink_halt_poll_ns(vcpu);
> -     else if (halt_poll_ns) {
> -             if (block_ns <= vcpu->halt_poll_ns)
> -                     ;
> -             /* we had a long block, shrink polling */
> -             else if (vcpu->halt_poll_ns && block_ns > halt_poll_ns)
> +     if (!kvm_arch_no_poll(vcpu)) {
> +             if (!vcpu_valid_wakeup(vcpu))
>                       shrink_halt_poll_ns(vcpu);
> -             /* we had a short halt and our poll time is too small */
> -             else if (vcpu->halt_poll_ns < halt_poll_ns &&
> -                     block_ns < halt_poll_ns)
> -                     grow_halt_poll_ns(vcpu);
> -     } else
> -             vcpu->halt_poll_ns = 0;
> +             else if (halt_poll_ns) {
> +                     if (block_ns <= vcpu->halt_poll_ns)
> +                             ;
> +                     /* we had a long block, shrink polling */
> +                     else if (vcpu->halt_poll_ns && block_ns > halt_poll_ns)
> +                             shrink_halt_poll_ns(vcpu);
> +                     /* we had a short halt and our poll time is too small */
> +                     else if (vcpu->halt_poll_ns < halt_poll_ns &&
> +                             block_ns < halt_poll_ns)
> +                             grow_halt_poll_ns(vcpu);
> +             } else
> +                     vcpu->halt_poll_ns = 0;
> +     }
>  
>       trace_kvm_vcpu_wakeup(block_ns, waited, vcpu_valid_wakeup(vcpu));
>       kvm_arch_vcpu_block_finish(vcpu);
> -- 
> 2.7.4

Looks good.

Reply via email to