linux-kernel - [PATCH v2 4/7] KVM: MMU: don't get free page number in the loop

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Message-ID: <4C09059E.2060205@cn.fujitsu.com>
Date:	Fri, 04 Jun 2010 21:54:38 +0800
From:	Xiao Guangrong <xiaoguangrong@...fujitsu.com>
To:	Avi Kivity <avi@...hat.com>
CC:	Marcelo Tosatti <mtosatti@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>,
	KVM list <kvm@...r.kernel.org>
Subject: [PATCH v2 4/7] KVM: MMU: don't get free page number in the loop

In the later patch, we will modify sp's zapping way like below:

	kvm_mmu_prepare_zap_page A
	kvm_mmu_prepare_zap_page B
	kvm_mmu_prepare_zap_page C
	....
	kvm_mmu_commit_zap_page

[ zaped multiple sps only need to call kvm_mmu_commit_zap_page once ]	

In __kvm_mmu_free_some_pages() function, the free page number is
getted form 'vcpu->kvm->arch.n_free_mmu_pages' in loop, it will
hinders us to apply kvm_mmu_prepare_zap_page() and kvm_mmu_commit_zap_page()
since kvm_mmu_prepare_zap_page() not free sp.

Signed-off-by: Xiao Guangrong <xiaoguangrong@...fujitsu.com>
---
 arch/x86/kvm/mmu.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index a64c0e0..77bc4ba 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2861,13 +2861,16 @@ EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt);
 
 void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
 {
-	while (vcpu->kvm->arch.n_free_mmu_pages < KVM_REFILL_PAGES &&
+	int free_pages;
+
+	free_pages = vcpu->kvm->arch.n_free_mmu_pages;
+	while (free_pages < KVM_REFILL_PAGES &&
 	       !list_empty(&vcpu->kvm->arch.active_mmu_pages)) {
 		struct kvm_mmu_page *sp;
 
 		sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,
 				  struct kvm_mmu_page, link);
-		kvm_mmu_zap_page(vcpu->kvm, sp);
+		free_pages += kvm_mmu_zap_page(vcpu->kvm, sp);
 		++vcpu->kvm->stat.mmu_recycled;
 	}
 }
-- 
1.6.1.2


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