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 6D60AC32774 for ; Tue, 23 Aug 2022 17:17:27 +0000 (UTC) Received: from localhost ([::1]:40122 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oQXWo-0007V2-8j for qemu-devel@archiver.kernel.org; Tue, 23 Aug 2022 13:17:26 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:39478) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oQXUI-0006ey-0L for qemu-devel@nongnu.org; Tue, 23 Aug 2022 13:14:50 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:58521) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oQXUB-0001iG-Bu for qemu-devel@nongnu.org; Tue, 23 Aug 2022 13:14:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1661274882; 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=/WjhRz/oaexJ5rV00mKzwsJNRZwX260x0x3kJtBvInA=; b=WjO/AetnZToVkBqbfI+an4evTxWYKV8N9RZQ9NkbIt25hvCtmfkqSM78oaMMMF0OlGo/MA B2ZnPCROZ90mGl51tQa7CSMiaDsr6gKjIAK5RpgeQDW5OeEDivOiKQh3clG85E2Rq9xAP4 TlzfeXagvlRFAFrcLxrFVl52uGp6mm4= 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-124-QpoozooeNH6BEPOGAMfbKQ-1; Tue, 23 Aug 2022 13:14:38 -0400 X-MC-Unique: QpoozooeNH6BEPOGAMfbKQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0AB6780231E; Tue, 23 Aug 2022 17:14:38 +0000 (UTC) Received: from redhat.com (unknown [10.33.37.31]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 900491415125; Tue, 23 Aug 2022 17:14:35 +0000 (UTC) Date: Tue, 23 Aug 2022 18:14:31 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Claudio Imbrenda Cc: pbonzini@redhat.com, qemu-devel@nongnu.org, david@redhat.com, cohuck@redhat.com, thuth@redhat.com, borntraeger@de.ibm.com, frankja@linux.ibm.com, fiuczy@linux.ibm.com, pasic@linux.ibm.com, alex.bennee@linaro.org, armbru@redhat.com, Murilo Opsfelder Araujo Subject: Re: [PATCH v4 1/1] os-posix: asynchronous teardown for shutdown on Linux Message-ID: References: <20220812133453.82671-1-imbrenda@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220812133453.82671-1-imbrenda@linux.ibm.com> User-Agent: Mutt/2.2.6 (2022-06-05) X-Scanned-By: MIMEDefang 2.85 on 10.11.54.7 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@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, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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 Fri, Aug 12, 2022 at 03:34:53PM +0200, Claudio Imbrenda wrote: > This patch adds support for asynchronously tearing down a VM on Linux. > > When qemu terminates, either naturally or because of a fatal signal, > the VM is torn down. If the VM is huge, it can take a considerable > amount of time for it to be cleaned up. In case of a protected VM, it > might take even longer than a non-protected VM (this is the case on > s390x, for example). > > Some users might want to shut down a VM and restart it immediately, > without having to wait. This is especially true if management > infrastructure like libvirt is used. > > This patch implements a simple trick on Linux to allow qemu to return > immediately, with the teardown of the VM being performed > asynchronously. > > If the new commandline option -async-teardown is used, a new process is > spawned from qemu at startup, using the clone syscall, in such way that > it will share its address space with qemu.The new process will have the > name "cleanup/". It will wait until qemu terminates > completely, and then it will exit itself. > > This allows qemu to terminate quickly, without having to wait for the > whole address space to be torn down. The cleanup process will exit > after qemu, so it will be the last user of the address space, and > therefore it will take care of the actual teardown. The cleanup > process will share the same cgroups as qemu, so both memory usage and > cpu time will be accounted properly. > > If possible, close_range will be used in the cleanup process to close > all open file descriptors. If it is not available or if it fails, /proc > will be used to determine which file descriptors to close. > > If the cleanup process is forcefully killed with SIGKILL before the > main qemu process has terminated completely, the mechanism is defeated > and the teardown will not be asynchronous. > > This feature can already be used with libvirt by adding the following > to the XML domain definition to pass the parameter to qemu directly: > > > > > > Signed-off-by: Claudio Imbrenda > Reviewed-by: Murilo Opsfelder Araujo > Tested-by: Murilo Opsfelder Araujo > --- > include/qemu/async-teardown.h | 22 +++++ > meson.build | 1 + > os-posix.c | 6 ++ > qemu-options.hx | 19 +++++ > util/async-teardown.c | 155 ++++++++++++++++++++++++++++++++++ > util/meson.build | 1 + > 6 files changed, 204 insertions(+) > create mode 100644 include/qemu/async-teardown.h > create mode 100644 util/async-teardown.c Reviewed-by: Daniel P. Berrangé 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 :|