linux-kernel - [PATCH] KVM: Remove redundant smp_mb() in the kvm_mmu_commit_zap

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Message-Id: <1457055312-27067-1-git-send-email-tianyu.lan@intel.com>
Date:	Fri,  4 Mar 2016 09:35:12 +0800
From:	Lan Tianyu <tianyu.lan@...el.com>
To:	gleb@...nel.org, pbonzini@...hat.com, tglx@...utronix.de,
	mingo@...hat.com, hpa@...or.com, x86@...nel.org
Cc:	Lan Tianyu <tianyu.lan@...el.com>, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] KVM: Remove redundant smp_mb() in the kvm_mmu_commit_zap_page()

The following kvm_flush_remote_tlbs() will call smp_mb() inside and so
remove smp_mb() here.

Signed-off-by: Lan Tianyu <tianyu.lan@...el.com>
---
 arch/x86/kvm/mmu.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index a54ecd9..6315416 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2383,12 +2383,6 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm,
 		return;
 
 	/*
-	 * wmb: make sure everyone sees our modifications to the page tables
-	 * rmb: make sure we see changes to vcpu->mode
-	 */
-	smp_mb();
-
-	/*
 	 * Wait for all vcpus to exit guest mode and/or lockless shadow
 	 * page table walks.
 	 */
-- 
1.8.4.rc0.1.g8f6a3e5.dirty