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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 5C4B9C2BA2B for ; Fri, 10 Apr 2020 06:46:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2449B20732 for ; Fri, 10 Apr 2020 06:46:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="KXeuZ0Y3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726009AbgDJGqo (ORCPT ); Fri, 10 Apr 2020 02:46:44 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:28376 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725816AbgDJGqo (ORCPT ); Fri, 10 Apr 2020 02:46:44 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1586501201; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=0zUfVt7mgJNJCuwkZj/ZTQSIXiHqwpNQ3G1o5Vhakx4=; b=KXeuZ0Y3Q4Fd1oRBxZdrCmwCr9pXYjt0e6MhyYKis8OyQqQr8KWvmUAOrdc70aWeFHfF9M KLhAI9PihDHgf0aaW9zMDYUVEPA6dJ1CAMSoXtCORYwLJsc/atu6GrOlNL8OCNgtZFOOQ1 YkBGCIYXta3WoMzYn0TjRL6M31G9pXM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-43-Z0rWAvSEOYaWut_WfuFMDw-1; Fri, 10 Apr 2020 02:46:36 -0400 X-MC-Unique: Z0rWAvSEOYaWut_WfuFMDw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 854D6107ACC4; Fri, 10 Apr 2020 06:46:31 +0000 (UTC) Received: from localhost (ovpn-13-236.pek2.redhat.com [10.72.13.236]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 21183272A6; Fri, 10 Apr 2020 06:46:29 +0000 (UTC) Date: Fri, 10 Apr 2020 14:46:26 +0800 From: Baoquan He To: Michal Hocko Cc: Mike Rapoport , Hoan Tran , Catalin Marinas , Will Deacon , Andrew Morton , Vlastimil Babka , Oscar Salvador , Pavel Tatashin , Alexander Duyck , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , "David S. Miller" , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , "open list:MEMORY MANAGEMENT" , linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, x86@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, lho@amperecomputing.com, mmorana@amperecomputing.com Subject: Re: [PATCH RFC] mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP (was: Re: [PATCH v3 0/5] mm: Enable CONFIG_NODES_SPAN_OTHER_NODES by default for NUMA) Message-ID: <20200410064626.GF2129@MiWiFi-R3L-srv> References: <1585420282-25630-1-git-send-email-Hoan@os.amperecomputing.com> <20200330074246.GA14243@dhcp22.suse.cz> <20200330092127.GB30942@linux.ibm.com> <20200330095843.GF14243@dhcp22.suse.cz> <20200331215618.GG30942@linux.ibm.com> <20200401054227.GC2129@MiWiFi-R3L-srv> <20200401075155.GH30942@linux.ibm.com> <20200402080144.GK22681@dhcp22.suse.cz> <20200409144119.GE2129@MiWiFi-R3L-srv> <20200409153321.GQ18386@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200409153321.GQ18386@dhcp22.suse.cz> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/09/20 at 05:33pm, Michal Hocko wrote: > On Thu 09-04-20 22:41:19, Baoquan He wrote: > > On 04/02/20 at 10:01am, Michal Hocko wrote: > > > On Wed 01-04-20 10:51:55, Mike Rapoport wrote: > > > > Hi, > > > > > > > > On Wed, Apr 01, 2020 at 01:42:27PM +0800, Baoquan He wrote: > > > [...] > > > > > From above information, we can remove HAVE_MEMBLOCK_NODE_MAP, and > > > > > replace it with CONFIG_NUMA. That sounds more sensible to store nid into > > > > > memblock when NUMA support is enabled. > > > > > > > > Replacing CONFIG_HAVE_MEMBLOCK_NODE_MAP with CONFIG_NUMA will work, but > > > > this will not help cleaning up the whole node/zone initialization mess and > > > > we'll be stuck with two implementations. > > > > > > Yeah, this is far from optimal. > > > > > > > The overhead of enabling HAVE_MEMBLOCK_NODE_MAP is only for init time as > > > > most architectures will anyway discard the entire memblock, so having it in > > > > a UMA arch won't be a problem. The only exception is arm that uses > > > > memblock for pfn_valid(), here we may also think about a solution to > > > > compensate the addition of nid to the memblock structures. > > > > > > Well, we can make memblock_region->nid defined only for CONFIG_NUMA. > > > memblock_get_region_node would then unconditionally return 0 on UMA. > > > Essentially the same way we do NUMA for other MM code. I only see few > > > direct usage of region->nid. > > > > Checked code again, seems HAVE_MEMBLOCK_NODE_MAP is selected directly in > > all ARCHes which support it. Means HAVE_MEMBLOCK_NODE_MAP is enabled by > > default on those ARCHes, and has no dependency on CONFIG_NUMA at all. > > E.g on x86, it just calls free_area_init_nodes() in generic code path, > > while free_area_init_nodes() is defined in CONFIG_HAVE_MEMBLOCK_NODE_MAP > > ifdeffery scope. So I tend to agree with Mike to remove > > HAVE_MEMBLOCK_NODE_MAP firstly on all ARCHes. We can check if it's worth > > only defining memblock_region->nid for CONFIG_NUMA case after > > HAVE_MEMBLOCK_NODE_MAP is removed. > > This can surely go in separate patches. What I meant to say is the > region->nid is by definition 0 on !CONFIG_NUMA. I see, thanks.