From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752180Ab3KYKUT (ORCPT ); Mon, 25 Nov 2013 05:20:19 -0500 Received: from mx1.redhat.com ([209.132.183.28]:13877 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750825Ab3KYKUR convert rfc822-to-8bit (ORCPT ); Mon, 25 Nov 2013 05:20:17 -0500 Date: Mon, 25 Nov 2013 12:19:43 +0200 From: Gleb Natapov To: Xiao Guangrong Cc: Marcelo Tosatti , avi.kivity@gmail.com, "pbonzini@redhat.com Bonzini" , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Eric Dumazet , Peter Zijlstra Subject: Re: [PATCH v3 07/15] KVM: MMU: introduce nulls desc Message-ID: <20131125101943.GS2108@redhat.com> References: <1382534973-13197-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com> <1382534973-13197-8-git-send-email-xiaoguangrong@linux.vnet.ibm.com> <20131122191429.GA13308@amt.cnet> <65EE805B-B5DB-4BD0-A057-E5FF78D96D67@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=cp1255 Content-Disposition: inline Content-Transfer-Encoding: 8BIT In-Reply-To: <65EE805B-B5DB-4BD0-A057-E5FF78D96D67@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 25, 2013 at 02:11:31PM +0800, Xiao Guangrong wrote: > > > > For example, nothing prevents lockless walker to move into some > > parent_ptes chain, right? > > No. > > The nulls can help us to detect this case, for parent_ptes, the nulls points > to "shadow page" but for rmaps, the nulls points to slot.arch.rmap. There > is no chance that the “rmap" is used as shadow page when slot-lock is held. > But meanwhile we will write protect non-last level sptes, no? Better to create separate slab caches for rmap and parent_ptes lists. -- Gleb.