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Date: Mon, 1 Nov 2010 11:25:30 +0200 From: Gleb Natapov <gleb@...hat.com> To: Xiao Guangrong <xiaoguangrong@...fujitsu.com> Cc: Avi Kivity <avi@...hat.com>, Marcelo Tosatti <mtosatti@...hat.com>, LKML <linux-kernel@...r.kernel.org>, KVM <kvm@...r.kernel.org> Subject: Re: [PATCH v2 4/7] KVM: avoid unnecessary wait for a async pf On Mon, Nov 01, 2010 at 05:01:28PM +0800, Xiao Guangrong wrote: > In current code, it checks async pf completion out of the wait context, > like this: > > if (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE && > !vcpu->arch.apf.halted) > r = vcpu_enter_guest(vcpu); > else { > ...... > kvm_vcpu_block(vcpu) > ^- waiting until 'async_pf.done' is not empty > } > > kvm_check_async_pf_completion(vcpu) > ^- delete list from async_pf.done > > So, if we check aysnc pf completion first, it can be blocked at > kvm_vcpu_block > > Fixed by mark the vcpu is unhalted in kvm_check_async_pf_completion() > path > > Signed-off-by: Xiao Guangrong <xiaoguangrong@...fujitsu.com> Acked-by: Gleb Natapov <gleb@...hat.com> > --- > arch/x86/kvm/x86.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 9b543f4..4da8485 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -6280,6 +6280,7 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu, > vcpu->arch.fault.address = work->arch.token; > kvm_inject_page_fault(vcpu); > } > + vcpu->arch.apf.halted = false; > } > > bool kvm_arch_can_inject_async_page_present(struct kvm_vcpu *vcpu) > -- > 1.7.0.4 -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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