From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH v5 8/8] KVM: MMU: zap pages in batch Date: Thu, 16 May 2013 14:45:59 +0200 Message-ID: <5194D507.5080005@redhat.com> References: <1368706673-8530-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com> <1368706673-8530-9-git-send-email-xiaoguangrong@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Cc: gleb@redhat.com, avi.kivity@gmail.com, mtosatti@redhat.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org To: Xiao Guangrong Return-path: Received: from mx1.redhat.com ([209.132.183.28]:62726 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753627Ab3EPMqL (ORCPT ); Thu, 16 May 2013 08:46:11 -0400 In-Reply-To: <1368706673-8530-9-git-send-email-xiaoguangrong@linux.vnet.ibm.com> Sender: kvm-owner@vger.kernel.org List-ID: Il 16/05/2013 14:17, Xiao Guangrong ha scritto: > Zap at lease 10 pages before releasing mmu-lock to reduce the overload > caused by requiring lock > > [ It improves kernel building 0.6% ~ 1% ] > > Signed-off-by: Xiao Guangrong > --- > arch/x86/kvm/mmu.c | 11 ++++++++--- > 1 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c > index e12f431..9c27fda 100644 > --- a/arch/x86/kvm/mmu.c > +++ b/arch/x86/kvm/mmu.c > @@ -4216,10 +4216,12 @@ restart: > spin_unlock(&kvm->mmu_lock); > } > > +#define BATCH_ZAP_PAGES 10 > static void zap_invalid_pages(struct kvm *kvm) > { > struct kvm_mmu_page *sp, *node; > LIST_HEAD(invalid_list); > + int batch = 0; > > restart: > list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link) { > @@ -4256,11 +4258,14 @@ restart: > * Need not flush tlb since we only zap the sp with invalid > * generation number. > */ > - if (cond_resched_lock(&kvm->mmu_lock)) > + if ((batch >= BATCH_ZAP_PAGES) && > + cond_resched_lock(&kvm->mmu_lock)) { > + batch = 0; > goto restart; > + } > > - if (kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list)) > - goto restart; > + batch += kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list); > + goto restart; Would this look again and again at the same page if kvm_mmu_prepare_zap_page returns 0? Paolo > } > > /* >