From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753055AbbJZFrO (ORCPT ); Mon, 26 Oct 2015 01:47:14 -0400 Received: from mga09.intel.com ([134.134.136.24]:36346 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751632AbbJZFrM (ORCPT ); Mon, 26 Oct 2015 01:47:12 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,200,1444719600"; d="scan'208";a="835405055" Message-ID: <562DBBC9.4000104@intel.com> Date: Mon, 26 Oct 2015 13:36:09 +0800 From: Lan Tianyu User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: Alexander Duyck , bhelgaas@google.com, carolyn.wyborny@intel.com, donald.c.skidmore@intel.com, eddie.dong@intel.com, nrupal.jani@intel.com, yang.z.zhang@intel.com, agraf@suse.de, kvm@vger.kernel.org, pbonzini@redhat.com, qemu-devel@nongnu.org, emil.s.tantilov@intel.com, intel-wired-lan@lists.osuosl.org, jeffrey.t.kirsher@intel.com, jesse.brandeburg@intel.com, john.ronciak@intel.com, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, matthew.vick@intel.com, mitch.a.williams@intel.com, netdev@vger.kernel.org, shannon.nelson@intel.com Subject: Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV NIC References: <1445445464-5056-1-git-send-email-tianyu.lan@intel.com> <562A7E33.4080800@gmail.com> In-Reply-To: <562A7E33.4080800@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015年10月24日 02:36, Alexander Duyck wrote: > I was thinking about it and I am pretty sure the dummy write approach is > problematic at best. Specifically the issue is that while you are > performing a dummy write you risk pulling in descriptors for data that > hasn't been dummy written to yet. So when you resume and restore your > descriptors you will have once that may contain Rx descriptors > indicating they contain data when after the migration they don't. How about changing sequence? dummy writing Rx packet data fist and then its desc. This can ensure that RX data is migrated before its desc and prevent such case. -- Best regards Tianyu Lan