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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF6A4C433FE for ; Mon, 27 Sep 2021 06:42:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9721360F4A for ; Mon, 27 Sep 2021 06:42:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233020AbhI0GoL (ORCPT ); Mon, 27 Sep 2021 02:44:11 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:46364 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233007AbhI0GoJ (ORCPT ); Mon, 27 Sep 2021 02:44:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1632724952; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dgUQa1q2yVLHuH43oDCQpdzXKKAxjWaL6vBqtSCv00M=; b=aseZ2k5tgTcAZc0QSA2kiugIe3aVZJ80x042v8OjqIUJoMO91fg7WeANfrfXZQ2DW2P4tl /j5CxH5Bsgc98OgTqRyA3cVJn+vRV1NAE7R/wsVKOLZxxpUmxSkaGSEnCEmwJW+kY+IDJK /aKZRo+zGneFozKghRh5SVKu/dW0Br8= 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-548-Up7L8uypM4ConrfU_bs3rA-1; Mon, 27 Sep 2021 02:42:28 -0400 X-MC-Unique: Up7L8uypM4ConrfU_bs3rA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 977BC1966320; Mon, 27 Sep 2021 06:42:26 +0000 (UTC) Received: from gshan.redhat.com (vpn2-54-16.bne.redhat.com [10.64.54.16]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9527560936; Mon, 27 Sep 2021 06:42:22 +0000 (UTC) From: Gavin Shan To: devicetree@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, robh@kernel.org, maz@kernel.org, rdunlap@infradead.org, catalin.marinas@arm.com, will@kernel.org, shan.gavin@gmail.com Subject: [PATCH v2 1/2] Documentation, dt, numa: Add note to empty NUMA node Date: Mon, 27 Sep 2021 14:41:18 +0800 Message-Id: <20210927064119.127285-2-gshan@redhat.com> In-Reply-To: <20210927064119.127285-1-gshan@redhat.com> References: <20210927064119.127285-1-gshan@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The empty memory nodes, where no memory resides in, are allowed. The NUMA node IDs are still valid and parsed, but memory may be added to them through hotplug afterwards. Currently, QEMU fails to boot when multiple empty memory nodes are specified. It's caused by device-tree population failure and duplicated memory node names. The device-tree specification doesn't provide how empty NUMA nodes are handled. Besides, I finds difficulty to get where this case is documented. So lets add a section for empty memory nodes to cover it in NUMA binding document. Signed-off-by: Gavin Shan --- Documentation/devicetree/bindings/numa.txt | 46 +++++++++++++++++++++- 1 file changed, 45 insertions(+), 1 deletion(-) diff --git a/Documentation/devicetree/bindings/numa.txt b/Documentation/devicetree/bindings/numa.txt index 21b35053ca5a..42f282c2f3cc 100644 --- a/Documentation/devicetree/bindings/numa.txt +++ b/Documentation/devicetree/bindings/numa.txt @@ -103,7 +103,51 @@ Example: }; ============================================================================== -4 - Example dts +4 - Empty memory nodes +============================================================================== + +Empty memory nodes, which no memory resides in, are allowed. There are no +device nodes for these empty memory nodes. However, the NUMA node IDs and +distance maps are still valid and 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@80000000 { + device_type = "memory"; + reg = <0x0 0x80000000 0x0 0x80000000>; + numa-node-id = <1>; + }; + + /* Empty memory node 2 and 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 -- 2.23.0