From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752790Ab1JXCrb (ORCPT ); Sun, 23 Oct 2011 22:47:31 -0400 Received: from mga01.intel.com ([192.55.52.88]:22941 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752668Ab1JXCra (ORCPT ); Sun, 23 Oct 2011 22:47:30 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.69,396,1315206000"; d="scan'208";a="80998220" Subject: Re: [PATCH 2/3] kvm: use this_cpu_xxx replace percpu_xxx funcs From: "Alex,Shi" To: Avi Kivity Cc: Christoph Lameter , "tj@kernel.org" , "linux-kernel@vger.kernel.org" , "eric.dumazet@gmail.com" , "Huang, Ying" , "tglx@linutronix.de" , "mingo@redhat.com" , "akpm@linux-foundation.org" , "davem@davemloft.net" , "kaber@trash.net" , "a.p.zijlstra@chello.nl" , "kvm@vger.kernel.org" , "jeremy@xensource.com" In-Reply-To: <1319096041.23426.182.camel@debian> References: <1318237851.27949.190.camel@debian> <1318324774.27949.693.camel@debian> <1318382964.27949.782.camel@debian> <1318428673.29699.13.camel@debian> <1318908091.23426.52.camel@debian> <1319016218.23426.104.camel@debian> <4E9E97D2.1040807@redhat.com> <1319096041.23426.182.camel@debian> Content-Type: text/plain; charset="UTF-8" Date: Mon, 24 Oct 2011 10:50:08 +0800 Message-ID: <1319424608.5061.25.camel@debian> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2011-10-20 at 15:34 +0800, Alex,Shi wrote: > percpu_xxx funcs are duplicated with this_cpu_xxx funcs, so replace them > for further code clean up. > > And in preempt safe scenario, __this_cpu_xxx funcs has a bit better > performance since __this_cpu_xxx has no redundant preempt_disable() > Avi: Would you like to give some comments of this? > Signed-off-by: Alex Shi > --- > arch/x86/kvm/x86.c | 14 +++++++------- > 1 files changed, 7 insertions(+), 7 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 84a28ea..432c4bc 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -5024,15 +5024,15 @@ static DEFINE_PER_CPU(struct kvm_vcpu *, current_vcpu); > > static int kvm_is_in_guest(void) > { > - return percpu_read(current_vcpu) != NULL; > + return __this_cpu_read(current_vcpu) != NULL; > } > > static int kvm_is_user_mode(void) > { > int user_mode = 3; > > - if (percpu_read(current_vcpu)) > - user_mode = kvm_x86_ops->get_cpl(percpu_read(current_vcpu)); > + if (__this_cpu_read(current_vcpu)) > + user_mode = kvm_x86_ops->get_cpl(__this_cpu_read(current_vcpu)); > > return user_mode != 0; > } > @@ -5041,8 +5041,8 @@ static unsigned long kvm_get_guest_ip(void) > { > unsigned long ip = 0; > > - if (percpu_read(current_vcpu)) > - ip = kvm_rip_read(percpu_read(current_vcpu)); > + if (__this_cpu_read(current_vcpu)) > + ip = kvm_rip_read(__this_cpu_read(current_vcpu)); > > return ip; > } > @@ -5055,13 +5055,13 @@ static struct perf_guest_info_callbacks kvm_guest_cbs = { > > void kvm_before_handle_nmi(struct kvm_vcpu *vcpu) > { > - percpu_write(current_vcpu, vcpu); > + __this_cpu_write(current_vcpu, vcpu); > } > EXPORT_SYMBOL_GPL(kvm_before_handle_nmi); > > void kvm_after_handle_nmi(struct kvm_vcpu *vcpu) > { > - percpu_write(current_vcpu, NULL); > + __this_cpu_write(current_vcpu, NULL); > } > EXPORT_SYMBOL_GPL(kvm_after_handle_nmi); >