From patchwork Thu Jun 20 11:41:16 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Igor Mammedov X-Patchwork-Id: 11006535 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BAABB14E5 for ; Thu, 20 Jun 2019 11:51:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A9486286D4 for ; Thu, 20 Jun 2019 11:51:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9E0FF286DB; Thu, 20 Jun 2019 11:51:50 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 4AE62286D4 for ; Thu, 20 Jun 2019 11:51:50 +0000 (UTC) Received: from localhost ([::1]:46576 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hdvbZ-0002JZ-Kz for patchwork-qemu-devel@patchwork.kernel.org; Thu, 20 Jun 2019 07:51:49 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55036) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hdvYd-00082C-JU for qemu-devel@nongnu.org; Thu, 20 Jun 2019 07:48:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hdvRh-0007US-6o for qemu-devel@nongnu.org; Thu, 20 Jun 2019 07:41:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39548) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hdvRd-0007QC-6v for qemu-devel@nongnu.org; Thu, 20 Jun 2019 07:41:33 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E5D4F308FE8D for ; Thu, 20 Jun 2019 11:41:23 +0000 (UTC) Received: from dell-r430-03.lab.eng.brq.redhat.com (dell-r430-03.lab.eng.brq.redhat.com [10.37.153.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id E0CE3608D0; Thu, 20 Jun 2019 11:41:20 +0000 (UTC) From: Igor Mammedov To: qemu-devel@nongnu.org Date: Thu, 20 Jun 2019 07:41:16 -0400 Message-Id: <20190620114116.27254-1-imammedo@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Thu, 20 Jun 2019 11:41:23 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH] deprecate -mem-path fallback to anonymous RAM 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: libvir-list@redhat.com, ehabkost@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Fallback might affect guest or worse whole host performance or functionality if backing file were used to share guest RAM with another process. Patch deprecates fallback so that we could remove it in future and ensure that QEMU will provide expected behavior and fail if it can't use user provided backing file. Signed-off-by: Igor Mammedov Reviewed-by: Daniel P. Berrangé Reviewed-by: Dr. David Alan Gilbert --- PS: Patch is written on top of [PATCH v4 0/3] numa: deprecate '-numa node, mem' and default memory distribution to avoid conflicts in qemu-deprecated.texi numa.c | 4 ++-- qemu-deprecated.texi | 8 ++++++++ 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/numa.c b/numa.c index 91a29138a2..53d67b8ad9 100644 --- a/numa.c +++ b/numa.c @@ -494,8 +494,8 @@ static void allocate_system_memory_nonnuma(MemoryRegion *mr, Object *owner, if (mem_prealloc) { exit(1); } - error_report("falling back to regular RAM allocation."); - + warn_report("falling back to regular RAM allocation. " + "Fallback to RAM allocation is deprecated."); /* Legacy behavior: if allocation failed, fall back to * regular RAM allocation. */ diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi index 2fe9b72121..2193705644 100644 --- a/qemu-deprecated.texi +++ b/qemu-deprecated.texi @@ -112,6 +112,14 @@ QEMU using implicit generic or board specific splitting rule. Use @option{memdev} with @var{memory-backend-ram} backend or @option{mem} (if it's supported by used machine type) to define mapping explictly instead. +@subsection -mem-path fallback to RAM (since 4.1) +Currently if system memory allocation from file pointed by @option{mem-path} +fails, QEMU fallbacks to allocating from anonymous RAM. Which might result +in unpredictable behavior since provided backing file wasn't used. In future +QEMU will not fallback and fail to start up, so user could fix his/her QEMU/host +configuration or explicitly use -m without -mem-path if system memory allocated +from anonymous RAM suits usecase. + @section QEMU Machine Protocol (QMP) commands @subsection block-dirty-bitmap-add "autoload" parameter (since 2.12.0)