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=-11.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 CCE38C433E2 for ; Wed, 2 Sep 2020 10:15:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A787E2078B for ; Wed, 2 Sep 2020 10:15:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726586AbgIBKP3 (ORCPT ); Wed, 2 Sep 2020 06:15:29 -0400 Received: from mx2.suse.de ([195.135.220.15]:56542 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726285AbgIBKP1 (ORCPT ); Wed, 2 Sep 2020 06:15:27 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id D97A3AC61; Wed, 2 Sep 2020 10:15:26 +0000 (UTC) Subject: Re: [PATCH v1 4/5] xen/balloon: try to merge system ram resources To: David Hildenbrand , linux-kernel@vger.kernel.org Cc: virtualization@lists.linux-foundation.org, linux-mm@kvack.org, linux-hyperv@vger.kernel.org, xen-devel@lists.xenproject.org, Andrew Morton , Michal Hocko , Boris Ostrovsky , Stefano Stabellini , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Julien Grall , Pankaj Gupta , Baoquan He , Wei Yang References: <20200821103431.13481-1-david@redhat.com> <20200821103431.13481-5-david@redhat.com> From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: <226413fc-ef25-59bd-772f-79012fda0ee3@suse.com> Date: Wed, 2 Sep 2020 12:15:25 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200821103431.13481-5-david@redhat.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 21.08.20 12:34, David Hildenbrand wrote: > Let's reuse the new mechanism to merge system ram resources below the > root. We are the only one hotplugging system ram (e.g., DIMMs don't apply), > so this is safe to be used. > > Cc: Andrew Morton > Cc: Michal Hocko > Cc: Boris Ostrovsky > Cc: Juergen Gross > Cc: Stefano Stabellini > Cc: Roger Pau Monné > Cc: Julien Grall > Cc: Pankaj Gupta > Cc: Baoquan He > Cc: Wei Yang > Signed-off-by: David Hildenbrand > --- > drivers/xen/balloon.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c > index 37ffccda8bb87..5ec73f752b8a7 100644 > --- a/drivers/xen/balloon.c > +++ b/drivers/xen/balloon.c > @@ -338,6 +338,10 @@ static enum bp_state reserve_additional_memory(void) > if (rc) { > pr_warn("Cannot add additional memory (%i)\n", rc); > goto err; > + } else { > + resource = NULL; > + /* Try to reduce the number of system ram resources. */ > + merge_system_ram_resources(&iomem_resource); > } I don't see the need for setting resource to NULL and to use an "else" clause here. Juergen