From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 503F3C43381 for ; Thu, 7 Mar 2019 02:46:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 176122064A for ; Thu, 7 Mar 2019 02:46:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727563AbfCGCqH (ORCPT ); Wed, 6 Mar 2019 21:46:07 -0500 Received: from mx1.redhat.com ([209.132.183.28]:46780 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726873AbfCGCqH (ORCPT ); Wed, 6 Mar 2019 21:46:07 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 65AF7C05090A; Thu, 7 Mar 2019 02:46:07 +0000 (UTC) Received: from [10.72.12.83] (ovpn-12-83.pek2.redhat.com [10.72.12.83]) by smtp.corp.redhat.com (Postfix) with ESMTP id A0A7C1001DD9; Thu, 7 Mar 2019 02:45:59 +0000 (UTC) Subject: Re: [RFC PATCH V2 5/5] vhost: access vq metadata through kernel virtual address To: "Michael S. Tsirkin" Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, peterx@redhat.com, linux-mm@kvack.org, aarcange@redhat.com References: <1551856692-3384-1-git-send-email-jasowang@redhat.com> <1551856692-3384-6-git-send-email-jasowang@redhat.com> <20190306092837-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: <15105894-4ec1-1ed0-1976-7b68ed9eeeda@redhat.com> Date: Thu, 7 Mar 2019 10:45:57 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190306092837-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Thu, 07 Mar 2019 02:46:07 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/3/7 上午12:31, Michael S. Tsirkin wrote: >> +static void vhost_set_vmap_dirty(struct vhost_vmap *used) >> +{ >> + int i; >> + >> + for (i = 0; i < used->npages; i++) >> + set_page_dirty_lock(used->pages[i]); > This seems to rely on page lock to mark page dirty. > > Could it happen that page writeback will check the > page, find it clean, and then you mark it dirty and then > invalidate callback is called? > > Yes. But does this break anything? The page is still there, we just remove a kernel mapping to it. Thanks