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=-17.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, 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 D16DBC2B9F4 for ; Fri, 25 Jun 2021 08:37:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B3B4F6141C for ; Fri, 25 Jun 2021 08:37:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229902AbhFYIjW (ORCPT ); Fri, 25 Jun 2021 04:39:22 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:52527 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229864AbhFYIjU (ORCPT ); Fri, 25 Jun 2021 04:39:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624610219; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jiGTpqScPyn0OOpdftLJOFCY/HfTcmoXaeFMThRMK7I=; b=IzzraJoCxwNFW/ACzBZf7FcaYAXzrwjljoWRTW9qAZzg9KchHLPwjP6vpgn+pRMhYVOBvM nDXDj2YMmFX9ZrN1lbV6PKFFtxiV91awGglXdFQp7EZVgZzgmdcTD4LdSLDtrYFdvUerW3 H4xhMela17dbOjxPFsk/miirf8pSB1Q= 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-270-fCPG14BiMzud5_W5JH6jiA-1; Fri, 25 Jun 2021 04:36:58 -0400 X-MC-Unique: fCPG14BiMzud5_W5JH6jiA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 23C48100C662; Fri, 25 Jun 2021 08:36:57 +0000 (UTC) Received: from [10.64.54.233] (vpn2-54-233.bne.redhat.com [10.64.54.233]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 66BA960E3A; Fri, 25 Jun 2021 08:36:50 +0000 (UTC) Reply-To: Gavin Shan Subject: Re: [PATCH v4] Documentation, dt, numa: Add note to empty NUMA node To: Andrew Jones Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, rdunlap@infradead.org, robh+dt@kernel.org, shan.gavin@gmail.com References: <20210625052338.4875-1-gshan@redhat.com> <20210625070217.4ffmfe7nwlusbbjc@gator> <20210625070656.j373hveemf5cdch4@gator> From: Gavin Shan Message-ID: <41643136-798b-a0f3-aee7-b6af94a2fc67@redhat.com> Date: Fri, 25 Jun 2021 18:36:48 +1000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.0 MIME-Version: 1.0 In-Reply-To: <20210625070656.j373hveemf5cdch4@gator> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 6/25/21 5:06 PM, Andrew Jones wrote: > On Fri, Jun 25, 2021 at 09:02:17AM +0200, Andrew Jones wrote: >> On Fri, Jun 25, 2021 at 01:23:38PM +0800, Gavin Shan wrote: >>> The empty memory nodes, where no memory resides in, are allowed. >>> For these empty memory nodes, the 'len' of 'reg' property is zero. >>> The NUMA node IDs are still valid and parsed, but memory can be >>> added to them through hotplug afterwards. I finds difficulty to >>> get where it's properly documented. >>> >>> So lets add note to empty memory nodes in the NUMA binding doc. >>> >>> Signed-off-by: Gavin Shan >>> --- >>> Documentation/devicetree/bindings/numa.txt | 4 ++++ >>> 1 file changed, 4 insertions(+) >>> >>> diff --git a/Documentation/devicetree/bindings/numa.txt b/Documentation/devicetree/bindings/numa.txt >>> index 21b35053ca5a..0fc882e44270 100644 >>> --- a/Documentation/devicetree/bindings/numa.txt >>> +++ b/Documentation/devicetree/bindings/numa.txt >>> @@ -109,6 +109,10 @@ Example: >>> Dual socket system consists of 2 boards connected through ccn bus and >>> each board having one socket/soc of 8 cpus, memory and pci bus. >>> >>> +Note that empty memory nodes, which no memory resides in, are allowed. >>> +The NUMA node IDs in these empty memory nodes are still valid, but >>> +memory can be added into them through hotplug afterwards. >> >> Please change the second sentence to: >> >> The NUMA node IDs in these empty memory nodes are still valid and >> memory may be added into them through hotplug afterwards. >> >> But, this doesn't look like the right place for this paragraph. You're >> adding the paragraph to the example section, but the example doesn't have >> any empty memory nodes. >> >> I think the paragraph should be added to section "2 - numa-node-id" and an > > Or maybe even create a new section for it. > >> example empty memory node should be provided. Also, the commit message >> talks about the length of 'reg' being zero, which is an important >> distinction which should also be documented. >> Drew, thanks for your comments. Yeah, it sounds sensible to create a new section for it and an example would be more helpful. Please check if below changes are fine to you. I probably need Randy's review again. I'm trying to avoid too many revisions for this sort of trivial patch, even though I already had. However, it's time frame for v5.14 and I'm pushing this to be merged during the cycle. --- a/Documentation/devicetree/bindings/numa.txt +++ b/Documentation/devicetree/bindings/numa.txt @@ -103,7 +103,65 @@ Example: }; ============================================================================== -4 - Example dts +4 - Empty memory node +============================================================================== + +Empty memory nodes, which no memory resides in, are allowed. The 'length' +field of 'reg' property is zero, but 'base-address' is dummy and invalid +for these empty memory nodes. However, the NUMA node IDs and distance maps +for them are still valid, but memory may be added into them through hotplug +afterwards. + +Example: + + memory@0 { + device_type = "memory"; + reg = <0x0 0x0 0x0 0x80000000>; + numa-node-id = <0>; + }; + + memory@0x80000000 { + device_type = "memory"; + reg = <0x0 0x80000000 0x0 0x80000000>; + numa-node-id = <1>; + }; + + /* Empty memory node */ + memory@0x100000000 { + device_type = "memory"; + reg = <0x1 0x0 0x0 0x0>; + numa-node-id = <2>; + }; + + /* Empty memory node */ + memory@0x180000000 { + device_type = "memory"; + reg = <0x1 0x80000000 0x0 0x0>; + numa-node-id = <3>; + }; + + distance-map { + compatible = "numa-distance-map-v1"; + distance-matrix = <0 0 10>, + <0 1 20>, + <0 2 40>, + <0 3 20>, + <1 0 20>, + <1 1 10>, + <1 2 20>, + <1 3 40>, + <2 0 40>, + <2 1 20>, + <2 2 10>, + <2 3 20>, + <3 0 20>, + <3 1 40>, + <3 2 20>, + <3 3 10>; + }; + +============================================================================== +5 - Example dts ============================================================================== Dual socket system consists of 2 boards connected through ccn bus and Thanks, Gavin