From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f51.google.com (mail-pb0-f51.google.com [209.85.160.51]) by kanga.kvack.org (Postfix) with ESMTP id 735A56B0035 for ; Fri, 11 Apr 2014 12:24:24 -0400 (EDT) Received: by mail-pb0-f51.google.com with SMTP id uo5so5578169pbc.24 for ; Fri, 11 Apr 2014 09:24:24 -0700 (PDT) Received: from mga02.intel.com (mga02.intel.com. [134.134.136.20]) by mx.google.com with ESMTP id ep2si4549627pbb.131.2014.04.11.09.24.23 for ; Fri, 11 Apr 2014 09:24:23 -0700 (PDT) Message-ID: <53481724.8020304@intel.com> Date: Fri, 11 Apr 2014 09:24:04 -0700 From: Dave Hansen MIME-Version: 1.0 Subject: Re: [PATCH] drivers/base/node.c: export physical address range of given node (Re: NUMA node information for pages) References: <87eh1ix7g0.fsf@x240.local.i-did-not-set--mail-host-address--so-tickle-me> <533a1563.ad318c0a.6a93.182bSMTPIN_ADDED_BROKEN@mx.google.com> <5343806c.100cc30a.0461.ffffc401SMTPIN_ADDED_BROKEN@mx.google.com> <5345fe27.82dab40a.0831.0af9SMTPIN_ADDED_BROKEN@mx.google.com> <53474709.e59ec20a.3bd5.3b91SMTPIN_ADDED_BROKEN@mx.google.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes , Naoya Horiguchi Cc: drepper@gmail.com, anatol.pomozov@gmail.com, jkosina@suse.cz, akpm@linux-foundation.org, xemul@parallels.com, paul.gortmaker@windriver.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org On 04/11/2014 04:00 AM, David Rientjes wrote: > On Thu, 10 Apr 2014, Naoya Horiguchi wrote: >> > Yes, that's right, but it seems to me that just node_start_pfn and node_end_pfn >> > is not enough because there can be holes (without any page struct backed) inside >> > [node_start_pfn, node_end_pfn), and it's not aware of memory hotplug. >> > > So? Who cares if there are non-addressable holes in part of the span? > Ulrich, correct me if I'm wrong, but it seems you're looking for just a > address-to-nodeid mapping (or pfn-to-nodeid mapping) and aren't actually > expecting that there are no holes in a node for things like acpi or I/O or > reserved memory. ... > I think trying to represent holes and handling different memory models and > hotplug in special ways is complete overkill. This isn't just about memory hotplug or different memory models. There are systems out there today, in production, that have layouts like this: |------Node0-----| |------Node1-----| and this: |------Node0-----| |-Node1-| For those systems, this interface has no meaning. Given a page in the shared-span areas, this interface provides no way to figure out which node it is in. If you want a non-portable hack that just works on one system, I'd suggest parsing the existing firmware tables. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org