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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 53E3EC43331 for ; Tue, 24 Mar 2020 15:09:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E68720775 for ; Tue, 24 Mar 2020 15:09:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727774AbgCXPJi (ORCPT ); Tue, 24 Mar 2020 11:09:38 -0400 Received: from mx2.suse.de ([195.135.220.15]:47802 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727567AbgCXPJh (ORCPT ); Tue, 24 Mar 2020 11:09:37 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 42C1FAC22; Tue, 24 Mar 2020 15:09:36 +0000 (UTC) Subject: Re: [PATCH 2/2] xen: enable BALLOON_MEMORY_HOTPLUG by default To: Roger Pau Monne , linux-kernel@vger.kernel.org Cc: Ian Jackson , Boris Ostrovsky , Stefano Stabellini , xen-devel@lists.xenproject.org References: <20200324150015.50496-1-roger.pau@citrix.com> <20200324150015.50496-2-roger.pau@citrix.com> From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: Date: Tue, 24 Mar 2020 16:09:35 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200324150015.50496-2-roger.pau@citrix.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 24.03.20 16:00, Roger Pau Monne wrote: > Without it a PVH dom0 is mostly useless, as it would balloon down huge > amounts of RAM in order get physical address space to map foreign > memory and grants, ultimately leading to an out of memory situation. > > Such option is also needed for HVM or PVH driver domains, since they > also require mapping grants into physical memory regions. > > Suggested-by: Ian Jackson > Signed-off-by: Roger Pau Monné > --- > Cc: Boris Ostrovsky > Cc: Juergen Gross > Cc: Stefano Stabellini > Cc: xen-devel@lists.xenproject.org > --- > drivers/xen/Kconfig | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig > index 57ddd6f4b729..c344bcffd89d 100644 > --- a/drivers/xen/Kconfig > +++ b/drivers/xen/Kconfig > @@ -13,6 +13,7 @@ config XEN_BALLOON > config XEN_BALLOON_MEMORY_HOTPLUG > bool "Memory hotplug support for Xen balloon driver" > depends on XEN_BALLOON && MEMORY_HOTPLUG > + default y > help > Memory hotplug support for Xen balloon driver allows expanding memory > available for the system above limit declared at system startup. > Another variant would be to set: default XEN_BACKEND This would match the reasoning for switching it on. Either way would be fine with me, so you can add Reviewed-by: Juergen Gross Juergen