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 576BECCD193 for ; Mon, 20 Oct 2025 09:56:02 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vAmc0-0001d4-Vp; Mon, 20 Oct 2025 05:55:33 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vAmbz-0001cw-Cp for qemu-devel@nongnu.org; Mon, 20 Oct 2025 05:55:31 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vAmbx-0002ks-93 for qemu-devel@nongnu.org; Mon, 20 Oct 2025 05:55:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1760954125; 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=ZurhzRc+Ec9Dh/UVaIlZxVQiEXRt2/bVhx6dsUNI2uQ=; b=KmpCya8QiF1w7kxwNLyNg+xu4Uxlv4/Rv/mNHJg+o4CimNc41HM9ST7rmp/y5ijMNsnyWH ct+WtpRinF621G5K6h6HdtALzp9Gps5Im0L7ZK+GXhuBKarCfh+7zIETe4Doo87f940fZv cQjMEL01ZSDmYEhefWC0FdkBeqTHGqE= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-314-cU0yIoijN5OjpDyGUq-TiQ-1; Mon, 20 Oct 2025 05:55:21 -0400 X-MC-Unique: cU0yIoijN5OjpDyGUq-TiQ-1 X-Mimecast-MFC-AGG-ID: cU0yIoijN5OjpDyGUq-TiQ_1760954120 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5CEC0195609F; Mon, 20 Oct 2025 09:55:19 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.45.242.19]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 69E5C19560A2; Mon, 20 Oct 2025 09:55:18 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id DBC7F21E6A27; Mon, 20 Oct 2025 11:55:15 +0200 (CEST) From: Markus Armbruster To: Alexandr Moshkov Cc: qemu-devel@nongnu.org, Raphael Norwitz , "Michael S. Tsirkin" , Stefano Garzarella , Kevin Wolf , Hanna Reitz , Peter Xu , Fabiano Rosas , Eric Blake , Markus Armbruster , Vladimir Sementsov-Ogievskiy Subject: Re: [PATCH 0/2] vhost-user-blk: support inflight migration In-Reply-To: <20251020054413.2614932-1-dtalexundeer@yandex-team.ru> (Alexandr Moshkov's message of "Mon, 20 Oct 2025 10:44:12 +0500") References: <20251020054413.2614932-1-dtalexundeer@yandex-team.ru> Date: Mon, 20 Oct 2025 11:55:15 +0200 Message-ID: <87a51l99to.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; 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, 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_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Alexandr Moshkov writes: > Hi! > > During inter-host migration, waiting for disk requests to be drained > in the vhost-user backend can incur significant downtime. > > This can be avoided if QEMU migrates the inflight region in vhost-user-blk. > Thus, during the qemu migration, the vhost-user backend can cancel all inflight requests and > then, after migration, they will be executed on another host. > > At first, I tried to implement migration for all vhost-user devices that support inflight at once, > but this would require a lot of changes both in vhost-user-blk (to transfer it to the base class) and > in the vhost-user-base base class (inflight implementation and remodeling + a large refactor). > > Therefore, for now I decided to leave this idea for later and > implement the migration of the inflight region first for vhost-user-blk. How is this work related to Vladimir's "vhost-user-blk: live-backend local migration"?