linux-kernel - [PATCH 2/3] kvm: use this_cpu_xxx replace percpu

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Message-ID: <1319096041.23426.182.camel@debian>
Date:	Thu, 20 Oct 2011 15:34:01 +0800
From:	"Alex,Shi" <alex.shi@...el.com>
To:	Avi Kivity <avi@...hat.com>
Cc:	Christoph Lameter <cl@...two.org>, "tj@...nel.org" <tj@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"eric.dumazet@...il.com" <eric.dumazet@...il.com>,
	"Huang, Ying" <ying.huang@...el.com>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"mingo@...hat.com" <mingo@...hat.com>,
	"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
	"davem@...emloft.net" <davem@...emloft.net>,
	"kaber@...sh.net" <kaber@...sh.net>,
	"a.p.zijlstra@...llo.nl" <a.p.zijlstra@...llo.nl>,
	"kvm@...r.kernel.org" <kvm@...r.kernel.org>,
	"jeremy@...source.com" <jeremy@...source.com>
Subject: [PATCH 2/3] kvm: use this_cpu_xxx replace percpu_xxx funcs

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()

Signed-off-by: Alex Shi <alex.shi@...el.com>
---
 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);
 
-- 
1.6.3.3



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