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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 8C2E6C433B4 for ; Thu, 6 May 2021 13:04:03 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BC126610FA for ; Thu, 6 May 2021 13:04:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BC126610FA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:48342 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ledfd-000855-H2 for qemu-devel@archiver.kernel.org; Thu, 06 May 2021 09:04:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46832) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ledeL-0007YN-6x for qemu-devel@nongnu.org; Thu, 06 May 2021 09:02:41 -0400 Received: from szxga03-in.huawei.com ([45.249.212.189]:2204) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ledeI-0001ic-Ic for qemu-devel@nongnu.org; Thu, 06 May 2021 09:02:40 -0400 Received: from dggeml757-chm.china.huawei.com (unknown [172.30.72.56]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4FbYYk6Zhwz5xhb; Thu, 6 May 2021 20:59:06 +0800 (CST) Received: from dggema765-chm.china.huawei.com (10.1.198.207) by dggeml757-chm.china.huawei.com (10.1.199.137) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Thu, 6 May 2021 21:02:23 +0800 Received: from [10.174.185.210] (10.174.185.210) by dggema765-chm.china.huawei.com (10.1.198.207) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Thu, 6 May 2021 21:02:22 +0800 From: Kunkun Jiang Subject: [question] The source cannot recover, if the destination fails in the last round of live migration To: Juan Quintela , "Dr. David Alan Gilbert" , "open list:All patches CC here" Message-ID: <7d87a3b7-86c9-9248-59dc-e1612a00e7c3@huawei.com> Date: Thu, 6 May 2021 21:02:22 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [10.174.185.210] X-ClientProxiedBy: dggeme715-chm.china.huawei.com (10.1.199.111) To dggema765-chm.china.huawei.com (10.1.198.207) X-CFilter-Loop: Reflected Received-SPF: pass client-ip=45.249.212.189; envelope-from=jiangkunkun@huawei.com; helo=szxga03-in.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Zenghui Yu , wanghaibin.wang@huawei.com, Keqian Zhu , Peter Xu , David Edmondson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi all, Recently I am learning about the part of live migration. I have a question about the last round. When the pending_size is less than the threshold, it will enter the last round and call migration_completion(). It will stop the source and sent the remaining dirty pages and devices' status information to the destination. The destination will load these information and start the VM. If there is an error at the destination at this time, it will exit directly, and the source will not be able to detect the error and recover. Because the source will not call migration_detect_error(). Is my understanding correct? Should the source wait the result of the last round of destination ? Thanks, Kunkun Jiang