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=-10.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 0C485C64E7C for ; Wed, 2 Dec 2020 11:10:08 +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 4C56D22203 for ; Wed, 2 Dec 2020 11:10:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C56D22203 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=tempfail smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:36522 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kkQ1K-0000Yi-2q for qemu-devel@archiver.kernel.org; Wed, 02 Dec 2020 06:10:02 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:56074) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kkPTe-00024e-Jx for qemu-devel@nongnu.org; Wed, 02 Dec 2020 05:35:14 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:33990) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kkPTa-00016W-3i for qemu-devel@nongnu.org; Wed, 02 Dec 2020 05:35:14 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1606905308; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=L6FNw8ZXMvzG4FYYN9Eqyd5K4oozoHU9dG0QGcyXlz4=; b=PL8J1ZPmsJaz0QLr0BnHLtKPeuu13u2f4fJPEkpTxmzv6OlMR5PAzJ9s/c1Oki1XrgvDWz XIfUNIClL/mowDUretw8ThEGt8to1xFHsvRUmxU+j3yE0fXJO4agTkv3jKEQwS2l7BjEWF Nd+GZ9xa94EuE5UDD0J0TTRvNm7CCiM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-84-fuavLcUpNlObnP0ObXRrNA-1; Wed, 02 Dec 2020 05:35:07 -0500 X-MC-Unique: fuavLcUpNlObnP0ObXRrNA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6DB681074641 for ; Wed, 2 Dec 2020 10:35:06 +0000 (UTC) Received: from redhat.com (ovpn-115-57.ams2.redhat.com [10.36.115.57]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AA49C60BFA; Wed, 2 Dec 2020 10:35:01 +0000 (UTC) Date: Wed, 2 Dec 2020 10:34:57 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: "Michael S. Tsirkin" Subject: Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest Message-ID: <20201202103457.GB2360260@redhat.com> References: <20201118083748.1328-1-quintela@redhat.com> <20201118083748.1328-2-quintela@redhat.com> <20201202050918-mutt-send-email-mst@kernel.org> <20201202102718.GA2360260@redhat.com> <20201202053111-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 In-Reply-To: <20201202053111-mutt-send-email-mst@kernel.org> User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -35 X-Spam_score: -3.6 X-Spam_bar: --- X-Spam_report: (-3.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.497, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Eduardo Habkost , Juan Quintela , Jason Wang , "Dr. David Alan Gilbert" , qemu-devel@nongnu.org, Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Dec 02, 2020 at 05:31:50AM -0500, Michael S. Tsirkin wrote: > On Wed, Dec 02, 2020 at 10:27:18AM +0000, Daniel P. Berrangé wrote: > > On Wed, Dec 02, 2020 at 05:13:18AM -0500, Michael S. Tsirkin wrote: > > > On Wed, Nov 18, 2020 at 09:37:22AM +0100, Juan Quintela wrote: > > > > If we have a paused guest, it can't unplug the network VF device, so > > > > we wait there forever. Just change the code to give one error on that > > > > case. > > > > > > > > Signed-off-by: Juan Quintela > > > > > > It's certainly possible but it's management that created > > > this situation after all - why do we bother to enforce > > > a policy? It is possible that management will unpause immediately > > > afterwards and everything will proceed smoothly. > > > > > > Yes migration will not happen until guest is > > > unpaused but the same it true of e.g. a guest that is stuck > > > because of a bug. > > > > That's pretty different behaviour from how migration normally handles > > a paused guest, which is that it is guaranteed to complete the migration > > in as short a time as network bandwidth allows. > > > > Just ignoring the situation I think will lead to surprise apps / admins, > > because the person/entity invoking the migration is not likely to have > > checked wether this particular guest uses net failover or not before > > invoking - they'll just be expecting a paused migration to run fast and > > be guaranteed to complete. > > Okay I guess. But then shouldn't we handle the reverse situation too: > pausing guest after migration started but before device was > unplugged? Yeah we likely want todo something there. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|