| Message ID | 1458127996-21799-1-git-send-email-liangchen.linux@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 16/03/2016 12:33, Liang Chen wrote: > Since accumulate_steal_time is now only called in record_steal_time, it > doesn't quite make sense to put the delta calculation in a separate > function. The function could be called thousands of times before guest > enables the steal time MSR (though the compiler may optimize out this > function call). And after it's enabled, the MSR enable bit is tested twice > every time. Removing the accumulate_steal_time function also avoids the > necessity of having the accum_steal field. > > Signed-off-by: Liang Chen <liangchen.linux@gmail.com> > Signed-off-by: Gavin Guo <gavin.guo@canonical.com> > --- > arch/x86/include/asm/kvm_host.h | 1 - > arch/x86/kvm/x86.c | 19 +++---------------- > 2 files changed, 3 insertions(+), 17 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 44adbb8..3f460a7 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -547,7 +547,6 @@ struct kvm_vcpu_arch { > struct { > u64 msr_val; > u64 last_steal; > - u64 accum_steal; > struct gfn_to_hva_cache stime; > struct kvm_steal_time steal; > } st; > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index eaf6ee8..82bfefc 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -2002,22 +2002,8 @@ static void kvmclock_reset(struct kvm_vcpu *vcpu) > vcpu->arch.pv_time_enabled = false; > } > > -static void accumulate_steal_time(struct kvm_vcpu *vcpu) > -{ > - u64 delta; > - > - if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED)) > - return; > - > - delta = current->sched_info.run_delay - vcpu->arch.st.last_steal; > - vcpu->arch.st.last_steal = current->sched_info.run_delay; > - vcpu->arch.st.accum_steal = delta; > -} > - > static void record_steal_time(struct kvm_vcpu *vcpu) > { > - accumulate_steal_time(vcpu); > - > if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED)) > return; > > @@ -2025,9 +2011,10 @@ static void record_steal_time(struct kvm_vcpu *vcpu) > &vcpu->arch.st.steal, sizeof(struct kvm_steal_time)))) > return; > > - vcpu->arch.st.steal.steal += vcpu->arch.st.accum_steal; > + vcpu->arch.st.steal.steal += current->sched_info.run_delay - > + vcpu->arch.st.last_steal; > + vcpu->arch.st.last_steal = current->sched_info.run_delay; > vcpu->arch.st.steal.version += 2; > - vcpu->arch.st.accum_steal = 0; > > kvm_write_guest_cached(vcpu->kvm, &vcpu->arch.st.stime, > &vcpu->arch.st.steal, sizeof(struct kvm_steal_time)); > Nice cleanup; queued for 4.7, thanks. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 44adbb8..3f460a7 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -547,7 +547,6 @@ struct kvm_vcpu_arch { struct { u64 msr_val; u64 last_steal; - u64 accum_steal; struct gfn_to_hva_cache stime; struct kvm_steal_time steal; } st; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index eaf6ee8..82bfefc 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2002,22 +2002,8 @@ static void kvmclock_reset(struct kvm_vcpu *vcpu) vcpu->arch.pv_time_enabled = false; } -static void accumulate_steal_time(struct kvm_vcpu *vcpu) -{ - u64 delta; - - if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED)) - return; - - delta = current->sched_info.run_delay - vcpu->arch.st.last_steal; - vcpu->arch.st.last_steal = current->sched_info.run_delay; - vcpu->arch.st.accum_steal = delta; -} - static void record_steal_time(struct kvm_vcpu *vcpu) { - accumulate_steal_time(vcpu); - if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED)) return; @@ -2025,9 +2011,10 @@ static void record_steal_time(struct kvm_vcpu *vcpu) &vcpu->arch.st.steal, sizeof(struct kvm_steal_time)))) return; - vcpu->arch.st.steal.steal += vcpu->arch.st.accum_steal; + vcpu->arch.st.steal.steal += current->sched_info.run_delay - + vcpu->arch.st.last_steal; + vcpu->arch.st.last_steal = current->sched_info.run_delay; vcpu->arch.st.steal.version += 2; - vcpu->arch.st.accum_steal = 0; kvm_write_guest_cached(vcpu->kvm, &vcpu->arch.st.stime, &vcpu->arch.st.steal, sizeof(struct kvm_steal_time));