[{"id":3680625,"web_url":"http://patchwork.ozlabs.org/comment/3680625/","msgid":"","list_archive_url":null,"date":"2026-04-22T13:16:16","subject":"Re: [PATCH v2 07/16] migration: Introduce stopcopy_bytes in\n save_query_pending()","submitter":{"id":89058,"url":"http://patchwork.ozlabs.org/api/people/89058/","name":"Juraj Marcin","email":"jmarcin@redhat.com"},"content":"On 2026-04-21 16:21, Peter Xu wrote:\n> Allow modules to report data that can only be migrated after VM is stopped.\n> \n> When this concept is introduced, we will need to account stopcopy size to\n> be part of pending_size as before.\n> \n> However, when there're data only can be migrated in stopcopy phase, it\n> means the old \"pending_size\" may not always be able to reach low enough to\n> kickoff an slow version of query sync.\n> \n> It used to be almost guaranteed to happen as all prior iterative modules\n> doesn't have stopcopy only data. VFIO may change that fact by having some\n> data that must be copied during stop phase.\n> \n> So we need to make sure QEMU will kickoff a synchronized version of query\n> pending when all precopy data is migrated. This might be important to VFIO\n> to keep making progress even if the downtime cannot yet be satisfied.\n> \n> So far, this patch should introduce no functional change, as no module yet\n> report stopcopy size.\n> \n> This paves way for VFIO to properly report its pending data sizes, which\n> will start to include stop-only data.\n> \n> Signed-off-by: Peter Xu \n> ---\n> include/migration/register.h | 7 ++++\n> migration/migration.c | 65 ++++++++++++++++++++++++++++++------\n> migration/savevm.c | 10 ++++--\n> migration/trace-events | 2 +-\n> 4 files changed, 70 insertions(+), 14 deletions(-)\n\nReviewed-by: Juraj Marcin ","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=W9s1AxkQ;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=google header.b=TuBuAEJB;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists1p.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)"],"Received":["from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g10BM1w9zz1y2d\n\tfor ; Wed, 22 Apr 2026 23:17:13 +1000 (AEST)","from localhost ([::1] helo=lists1p.gnu.org)\n\tby lists1p.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from )\n\tid 1wFXRZ-0003BF-UU; Wed, 22 Apr 2026 09:16:42 -0400","from eggs.gnu.org ([2001:470:142:3::10])\n by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from )\n id 1wFXRY-0003Av-BB\n for qemu-devel@nongnu.org; Wed, 22 Apr 2026 09:16:40 -0400","from us-smtp-delivery-124.mimecast.com ([170.10.133.124])\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from )\n id 1wFXRW-0005GL-RJ\n for qemu-devel@nongnu.org; Wed, 22 Apr 2026 09:16:40 -0400","from mail-pl1-f200.google.com (mail-pl1-f200.google.com\n [209.85.214.200]) by relay.mimecast.com with ESMTP with STARTTLS\n (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id\n us-mta-364-TmfVoUTSO7Kq71TNYHDAfw-1; Wed, 22 Apr 2026 09:16:35 -0400","by mail-pl1-f200.google.com with SMTP id\n d9443c01a7336-2b24a00d12cso55421165ad.1\n for ; Wed, 22 Apr 2026 06:16:34 -0700 (PDT)","from fedora (193-179-61-20.customers.tmcz.cz. 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Szmigiero\" ","Subject":"Re: [PATCH v2 07/16] migration: Introduce stopcopy_bytes in\n save_query_pending()","Message-ID":"","References":"<20260421202110.306051-1-peterx@redhat.com>\n <20260421202110.306051-8-peterx@redhat.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=us-ascii","Content-Disposition":"inline","In-Reply-To":"<20260421202110.306051-8-peterx@redhat.com>","Received-SPF":"pass client-ip=170.10.133.124; envelope-from=jmarcin@redhat.com;\n helo=us-smtp-delivery-124.mimecast.com","X-Spam_score_int":"-20","X-Spam_score":"-2.1","X-Spam_bar":"--","X-Spam_report":"(-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_PASS=-0.001,\n 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":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"}}]