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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 D2276C48BD6 for ; Wed, 26 Jun 2019 10:35:18 +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 ACD3620663 for ; Wed, 26 Jun 2019 10:35:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ACD3620663 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]:38710 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hg5Gn-0002a9-VV for qemu-devel@archiver.kernel.org; Wed, 26 Jun 2019 06:35:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:52881) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hg5F5-0001YP-DP for qemu-devel@nongnu.org; Wed, 26 Jun 2019 06:33:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hg5F4-0004Zb-6k for qemu-devel@nongnu.org; Wed, 26 Jun 2019 06:33:31 -0400 Received: from mail-wr1-f68.google.com ([209.85.221.68]:34974) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1hg5F4-0004FZ-0b for qemu-devel@nongnu.org; Wed, 26 Jun 2019 06:33:30 -0400 Received: by mail-wr1-f68.google.com with SMTP id f15so2140389wrp.2 for ; Wed, 26 Jun 2019 03:33:10 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:openpgp:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=6FEoyIJFmiCe378e7DrgdHINSy2kAjijN6BA1YKUcwo=; b=rYYRcQVfrufh18sdimE3T8eNfh81w81QihLUouSR66XTSGyd57Nt0DNXOK74AW0G+Y TgVA+ODaGX0YuohxH23EDUcpu6MSe3anEH9GcFXoSfJwe3lthfqUYF5sX3YpTotFg5/J mYylZ4rmrxUGA2C6mpg6NVTA2pE6vpDgb/N82wQo2emkGJg+Y5hd8Er0+KX8kntnYibn HfPftterwnBRo8z99R3tNzvhRU2/wHwI+PbzdZij/3sPXB2/fftCxEg8tU0XW4edaIDu QHfOraxeia79Ktz5r0Ws6HERroPF3cjwey7/uQahj5k8hGQQjmmoSF/O3PCyTdeeeNn7 xsEA== X-Gm-Message-State: APjAAAVzSqJMLGJdlm5YrTL9JRugKY/y2NrIMcCXmVe2UcypIYmBVzZd WGq2dtE9JeX5udrU53Y0XYGxzA== X-Google-Smtp-Source: APXvYqwR0q7AIoAas6DS7DsDBWWi6X7UPuKVDlPim9PeIn3ZyQjPhdZ8u/UtElTf5zoZEdCIswAnbA== X-Received: by 2002:adf:e88e:: with SMTP id d14mr2900767wrm.189.1561545189282; Wed, 26 Jun 2019 03:33:09 -0700 (PDT) Received: from [10.201.33.53] ([195.166.127.210]) by smtp.gmail.com with ESMTPSA id h21sm2254743wmb.47.2019.06.26.03.33.08 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Wed, 26 Jun 2019 03:33:08 -0700 (PDT) To: Igor Mammedov , qemu-devel@nongnu.org References: <20190626074228.11558-1-imammedo@redhat.com> From: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= Openpgp: id=89C1E78F601EE86C867495CBA2A3FD6EDEADC0DE; url=http://pgp.mit.edu/pks/lookup?op=get&search=0xA2A3FD6EDEADC0DE Message-ID: Date: Wed, 26 Jun 2019 12:33:07 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20190626074228.11558-1-imammedo@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.85.221.68 Subject: Re: [Qemu-devel] [PATCH v3] 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: armbru@redhat.com, berrange@redhat.com, ehabkost@redhat.com, dgilbert@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 6/26/19 9:42 AM, Igor Mammedov wrote: > 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: Markus Armbruster Reviewed-by: Philippe Mathieu-Daudé > --- > v2: > * improve text language > (Markus Armbruster ) > v3: > * drop confusing 'or QEMU will fail to start' in error message > * fix up grammar error > (Markus Armbruster ) > > numa.c | 6 ++++-- > qemu-deprecated.texi | 9 +++++++++ > 2 files changed, 13 insertions(+), 2 deletions(-) > > diff --git a/numa.c b/numa.c > index 91a29138a2..1994ab0655 100644 > --- a/numa.c > +++ b/numa.c > @@ -494,8 +494,10 @@ 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"); > + error_printf("This is deprecated. Make sure that -mem-path " > + " specified path has sufficient resources to allocate" > + " -m specified RAM amount"); > /* Legacy behavior: if allocation failed, fall back to > * regular RAM allocation. > */ > diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi > index 2fe9b72121..9cba82d5ec 100644 > --- a/qemu-deprecated.texi > +++ b/qemu-deprecated.texi > @@ -112,6 +112,15 @@ 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 guest RAM allocation from file pointed by @option{mem-path} > +fails, QEMU falls back to allocating from RAM, which might result > +in unpredictable behavior since the backing file specified by the user > +is ignored. In the future, users will be responsible for making sure > +the backing storage specified with @option{-mem-path} can actually provide > +the guest RAM configured with @option{-m} and QEMU will fail to start up if > +RAM allocation is unsuccessful. > + > @section QEMU Machine Protocol (QMP) commands > > @subsection block-dirty-bitmap-add "autoload" parameter (since 2.12.0) >