From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xiao Guangrong Subject: Re: [PATCH 2/6] KVM MMU: fix kvm_mmu_zap_page() and its calling path Date: Wed, 14 Apr 2010 10:14:29 +0800 Message-ID: <4BC52505.6000502@cn.fujitsu.com> References: <4BC2D2E2.1030604@cn.fujitsu.com> <4BC2D345.100@cn.fujitsu.com> <20100412171037.GB4976@amt.cnet> <4BC3CA16.6020106@cn.fujitsu.com> <20100413145927.GA24128@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Avi Kivity , KVM list , LKML To: Marcelo Tosatti Return-path: In-Reply-To: <20100413145927.GA24128@amt.cnet> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Marcelo Tosatti wrote: > On Tue, Apr 13, 2010 at 09:34:14AM +0800, Xiao Guangrong wrote: >> >> Marcelo Tosatti wrote: >> >>>> @@ -1483,8 +1483,8 @@ static int mmu_zap_unsync_children(struct kvm *kvm, >>>> for_each_sp(pages, sp, parents, i) { >>>> kvm_mmu_zap_page(kvm, sp); >>>> mmu_pages_clear_parents(&parents); >>>> + zapped++; >>>> } >>>> - zapped += pages.nr; >>>> kvm_mmu_pages_init(parent, &parents, &pages); >>>> } >>> Don't see why this is needed? The for_each_sp loop uses pvec.nr. >> I think mmu_zap_unsync_children() should return the number of zapped pages then we >> can adjust the number of free pages in kvm_mmu_change_mmu_pages(), but pages.nr no >> only includes the unsync/zapped pages but also includes their parents. > > Oh i see. I think its safer to check for list_empty then to rely on > proper accounting there, like __kvm_mmu_free_some_pages does. Do you mean that we'd better add WARN_ON(list_empty()) code in kvm_mmu_zap_page()? Thanks, Xiao