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=-5.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 B2EA3C433E0 for ; Wed, 3 Feb 2021 13:41:09 +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 E200D64E2B for ; Wed, 3 Feb 2021 13:41:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E200D64E2B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:44442 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l7IP5-00031m-NZ for qemu-devel@archiver.kernel.org; Wed, 03 Feb 2021 08:41:07 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:34080) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l7INi-0002Pt-9D for qemu-devel@nongnu.org; Wed, 03 Feb 2021 08:39:42 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:31705) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l7INg-0005Km-MO for qemu-devel@nongnu.org; Wed, 03 Feb 2021 08:39:42 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612359580; h=from:from: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=0xtjWJuTmH5XdTCapqVv1HPn+ANwV4oNSWaKAOCbax0=; b=OY/pL067HV9cFJB3GQJQ5TEbOEhuiUD1TQZtYeXyVOjYrQSlaEoZQI6hNEmAf2eNCAkkbi OlPsMt1Au8XQd8CulvQCldrapaaA1/0ZjUG7RSjw/5PJZdP8LRMtkPsPA9OaSz2uGnbkDC xjcfyrW/F3NMfL6fwOmHSgVrSLkIwzY= 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-577-5MCtCHdJM2C8hW-FV1clNw-1; Wed, 03 Feb 2021 08:39:38 -0500 X-MC-Unique: 5MCtCHdJM2C8hW-FV1clNw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5380C85EE60; Wed, 3 Feb 2021 13:39:37 +0000 (UTC) Received: from angien.pipo.sk (unknown [10.40.208.53]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5FAD6E15B; Wed, 3 Feb 2021 13:39:35 +0000 (UTC) Date: Wed, 3 Feb 2021 14:39:32 +0100 From: Peter Krempa To: Vladimir Sementsov-Ogievskiy Subject: Re: [PATCH 2/2] migration: dirty-bitmap: Allow control of bitmap persistence on destination Message-ID: <20210203133932.GF54538@angien.pipo.sk> References: <3afd4b353cf75c01c9260ca65e073d897e8c42d2.1612356810.git.pkrempa@redhat.com> <20210203132744.GE54538@angien.pipo.sk> MIME-Version: 1.0 In-Reply-To: <20210203132744.GE54538@angien.pipo.sk> X-PGP-Key-ID: 0xD018682B X-PGP-Key-Fingerprint: D294 FF38 A6A2 BF40 6C75 5DEF 36EC 16AC D018 682B User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=pkrempa@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=pkrempa@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -32 X-Spam_score: -3.3 X-Spam_bar: --- X-Spam_report: (-3.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.539, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=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: , Cc: John Snow , qemu-devel@nongnu.org, qemu-block@nongnu.org, Markus Armbruster Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Feb 03, 2021 at 14:27:49 +0100, Peter Krempa wrote: > On Wed, Feb 03, 2021 at 16:23:21 +0300, Vladimir Sementsov-Ogievskiy wrote: > > 03.02.2021 16:00, Peter Krempa wrote: > > > Bitmap's source persistence is transported over the migration stream and > > > the destination mirrors it. In some cases the destination might want to > > > persist bitmaps which are not persistent on the source (e.g. the result > > > of merge of bitmaps from a number of layers on the source when migrating > > > into a squashed image) > > > > Why not make merge target on source be persistent itself? Then it will be persistent on migration destination. > > Because they are temporary on the source. I don't want to make it > persistent in case of a failure so that it doesn't get written to the > disk e.g. in case of VM shutdown. To be a bit more specific, I don't want the bitmaps to stay in the image, that means that I'd have to also delete them on the source after a successfull migration before qemu is terminated, which might not even be possible since source deactivates storage after migration. So making them persistent on source is impossible. > > > > > > but currently it would need to create another set > > > of persistent bitmaps and merge them. > > > > > > This adds 'dest-persistent' optional property to > > > 'BitmapMigrationBitmapAlias' which when present overrides the bitmap > > > presence state from the source. > > > > It's seems simpler to make a separate qmp command block-dirty-bitmap-make-persistent.. Didn't you consider this way? > > I'm not sure how the internals work entirely. In my case it's way > simpler to do this setup when generating the mapping which I need to do > anyways rather than calling separate commands. Similarly here, after a successful migration I'd have to go and make all the bitmaps persistent, which is an extra step, and also a vector for possible failures after migration which also doesn't seem appealing.