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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 495E9C433FE for ; Thu, 13 Oct 2022 09:02:26 +0000 (UTC) Received: from localhost ([::1]:44784 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oiu6j-0003PA-AP for qemu-devel@archiver.kernel.org; Thu, 13 Oct 2022 05:02:25 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59262) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oitNK-0005v6-1u for qemu-devel@nongnu.org; Thu, 13 Oct 2022 04:15:30 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:42011) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oitND-000289-Cq for qemu-devel@nongnu.org; Thu, 13 Oct 2022 04:15:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1665648921; 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:in-reply-to:in-reply-to: references:references; bh=/as0WB4+8GRntlUAZkae+fBfwIZzB51gqmUF20F7zfs=; b=SvHJmr4+PpzIeLriGeXlvsZfN6be/6kA6EfG5sHSpsAyWqEMWHy1/UpZhqHTSn+9LNsGsF RoxUh47ITMOW6wykl/H2RGX6j4hqBAehhEmiTYgR0qJeA/crh2PUA3LPX+Sa08UHV7o6qn U4fNXb8v4AC2x+NT8t0nAhXW2BSNrUs= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-249-jxRLAmQ0NJGmUahHghQuSg-1; Thu, 13 Oct 2022 04:15:20 -0400 X-MC-Unique: jxRLAmQ0NJGmUahHghQuSg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5797B833A0D; Thu, 13 Oct 2022 08:15:20 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.27]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B6615C15BB9; Thu, 13 Oct 2022 08:15:19 +0000 (UTC) Date: Thu, 13 Oct 2022 09:15:17 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: "manish.mishra" Cc: qemu-devel , Juan Quintela Subject: Re: MultiFD and default channel out of order mapping on receive side. Message-ID: References: <9f02255a-ceb9-9ca6-2606-b91c5e9e6459@nutanix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <9f02255a-ceb9-9ca6-2606-b91c5e9e6459@nutanix.com> User-Agent: Mutt/2.2.7 (2022-08-07) X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Oct 13, 2022 at 01:23:40AM +0530, manish.mishra wrote: > Hi Everyone, > Hope everyone is doing great. I have seen some live migration issues with qemu-4.2 when using multiFD. Signature of issue is something like this. > 2022-10-01T09:57:53.972864Z qemu-kvm: failed to receive packet via multifd channel 0: multifd: received packet magic 5145564d expected 11223344 > > Basically default live migration channel packet is received on multiFD channel. I see a older patch explaining potential reason for this behavior. > https://lists.gnu.org/archive/html/qemu-devel/2019-10/msg05920.html > > [PATCH 3/3] migration/multifd: fix potential wrong acception order of IO. > > But i see this patch was not merged. By looking at qemu master code, i > could not find any other patch too which can handle this issue. So as > per my understanding this is still a potential issue even in qemu > master. I mainly wanted to check why this patch was dropped? See my repllies in that message - it broke compatilibity of data on the wire, meaning old QEMU can't talk to new QEMU and vica-verca. We need a fix for this issue, but it needs to take into account wire compatibility. With 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 :|