From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl1-f198.google.com (mail-pl1-f198.google.com [209.85.214.198]) by kanga.kvack.org (Postfix) with ESMTP id 1DFAD6B0332 for ; Thu, 15 Nov 2018 08:57:13 -0500 (EST) Received: by mail-pl1-f198.google.com with SMTP id y2so6892433plr.8 for ; Thu, 15 Nov 2018 05:57:13 -0800 (PST) Received: from bombadil.infradead.org (bombadil.infradead.org. [2607:7c80:54:e::133]) by mx.google.com with ESMTPS id 3-v6si28010306plm.136.2018.11.15.05.57.11 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 15 Nov 2018 05:57:11 -0800 (PST) Date: Thu, 15 Nov 2018 05:57:10 -0800 From: Matthew Wilcox Subject: Re: [PATCH 1/7] node: Link memory nodes to their compute nodes Message-ID: <20181115135710.GD19286@bombadil.infradead.org> References: <20181114224921.12123-2-keith.busch@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181114224921.12123-2-keith.busch@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Keith Busch Cc: linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-mm@kvack.org, Greg Kroah-Hartman , Rafael Wysocki , Dave Hansen , Dan Williams 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.