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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 4B128C43441 for ; Thu, 15 Nov 2018 15:02:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1723E223DD for ; Thu, 15 Nov 2018 15:02:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1723E223DD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388534AbeKPBK5 (ORCPT ); Thu, 15 Nov 2018 20:10:57 -0500 Received: from mga09.intel.com ([134.134.136.24]:2786 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726185AbeKPBK5 (ORCPT ); Thu, 15 Nov 2018 20:10:57 -0500 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 15 Nov 2018 07:02:45 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,236,1539673200"; d="scan'208";a="281348564" Received: from unknown (HELO localhost.localdomain) ([10.232.112.69]) by fmsmga006.fm.intel.com with ESMTP; 15 Nov 2018 07:02:45 -0800 Date: Thu, 15 Nov 2018 07:59:20 -0700 From: Keith Busch To: Matthew Wilcox Cc: linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-mm@kvack.org, Greg Kroah-Hartman , Rafael Wysocki , Dave Hansen , Dan Williams Subject: Re: [PATCH 1/7] node: Link memory nodes to their compute nodes Message-ID: <20181115145920.GG11416@localhost.localdomain> References: <20181114224921.12123-2-keith.busch@intel.com> <20181115135710.GD19286@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181115135710.GD19286@bombadil.infradead.org> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 15, 2018 at 05:57:10AM -0800, Matthew Wilcox wrote: > On Wed, Nov 14, 2018 at 03:49:14PM -0700, Keith Busch wrote: > > Memory-only nodes will often have affinity to a compute node, and > > platforms have ways to express that locality relationship. > > > > A node containing CPUs or other DMA devices that can initiate memory > > access are referred to as "memory iniators". A "memory target" is a > > node that provides at least one phyiscal address range accessible to a > > memory initiator. > > I think I may be confused here. If there is _no_ link from node X to > node Y, does that mean that node X's CPUs cannot access the memory on > node Y? In my mind, all nodes can access all memory in the system, > just not with uniform bandwidth/latency. The link is just about which nodes are "local". It's like how nodes have a cpulist. Other CPUs not in the node's list can acces that node's memory, but the ones in the mask are local, and provide useful optimization hints. Would a node mask would be prefered to symlinks?