Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761241AbZCaACw (ORCPT ); Mon, 30 Mar 2009 20:02:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759945AbZCaABP (ORCPT ); Mon, 30 Mar 2009 20:01:15 -0400 Received: from mx2.redhat.com ([66.187.237.31]:59768 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759822AbZCaABO (ORCPT ); Mon, 30 Mar 2009 20:01:14 -0400 From: Izik Eidus Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, avi@redhat.com, aarcange@redhat.com, chrisw@redhat.com, riel@redhat.com, jeremy@goop.org, mtosatti@redhat.com, hugh@veritas.com, corbet@lwn.net, yaniv@redhat.com, dmonakhov@openvz.org, Izik Eidus Subject: [PATCH 1/3] kvm: dont hold pagecount reference for mapped sptes pages. Date: Tue, 31 Mar 2009 03:00:02 +0300 Message-Id: <1238457604-7637-2-git-send-email-ieidus@redhat.com> In-Reply-To: <1238457604-7637-1-git-send-email-ieidus@redhat.com> References: <1238457604-7637-1-git-send-email-ieidus@redhat.com> To: unlisted-recipients:; (no To-header on input) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1761 Lines: 50 When using mmu notifiers, we are allowed to remove the page count reference tooken by get_user_pages to a specific page that is mapped inside the shadow page tables. This is needed so we can balance the pagecount against mapcount checking. (Right now kvm increase the pagecount and does not increase the mapcount when mapping page into shadow page table entry, so when comparing pagecount against mapcount, you have no reliable result.) Signed-off-by: Izik Eidus --- arch/x86/kvm/mmu.c | 7 ++----- 1 files changed, 2 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index b625ed4..df8fbaf 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -567,9 +567,7 @@ static void rmap_remove(struct kvm *kvm, u64 *spte) if (*spte & shadow_accessed_mask) kvm_set_pfn_accessed(pfn); if (is_writeble_pte(*spte)) - kvm_release_pfn_dirty(pfn); - else - kvm_release_pfn_clean(pfn); + kvm_set_pfn_dirty(pfn); rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt], is_large_pte(*spte)); if (!*rmapp) { printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte); @@ -1812,8 +1810,7 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte, page_header_update_slot(vcpu->kvm, shadow_pte, gfn); if (!was_rmapped) { rmap_add(vcpu, shadow_pte, gfn, largepage); - if (!is_rmap_pte(*shadow_pte)) - kvm_release_pfn_clean(pfn); + kvm_release_pfn_clean(pfn); } else { if (was_writeble) kvm_release_pfn_dirty(pfn); -- 1.5.6.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/