From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx133.postini.com [74.125.245.133]) by kanga.kvack.org (Postfix) with SMTP id B3F1D6B002B for ; Thu, 13 Dec 2012 18:15:44 -0500 (EST) Message-ID: <1355440542.1823.21.camel@buesod1.americas.hpqcorp.net> Subject: Re: [PATCH] mm: add node physical memory range to sysfs From: Davidlohr Bueso Date: Thu, 13 Dec 2012 15:15:42 -0800 In-Reply-To: <50C95E4A.9010509@linux.vnet.ibm.com> References: <1354919696.2523.6.camel@buesod1.americas.hpqcorp.net> <20121207155125.d3117244.akpm@linux-foundation.org> <50C28720.3070205@linux.vnet.ibm.com> <1355361524.5255.9.camel@buesod1.americas.hpqcorp.net> <50C933E9.2040707@linux.vnet.ibm.com> <1355364222.9244.3.camel@buesod1.americas.hpqcorp.net> <50C95E4A.9010509@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: Andrew Morton , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Wed, 2012-12-12 at 20:49 -0800, Dave Hansen wrote: > On 12/12/2012 06:03 PM, Davidlohr Bueso wrote: > > On Wed, 2012-12-12 at 17:48 -0800, Dave Hansen wrote: > >> But if we went and did it per-DIMM (showing which physical addresses and > >> NUMA nodes a DIMM maps to), wouldn't that be redundant with this > >> proposed interface? > > > > If DIMMs overlap between nodes, then we wouldn't have an exact range for > > a node in question. Having both approaches would complement each other. > > How is that possible? If NUMA nodes are defined by distances from CPUs > to memory, how could a DIMM have more than a single distance to any > given CPU? Can't this occur when interleaving emulated nodes with physical ones? > > >> How do you plan to use this in practice, btw? > > > > It started because I needed to recognize the address of a node to remove > > it from the e820 mappings and have the system "ignore" the node's > > memory. > > Actually, now that I think about it, can you check in the > /sys/devices/system/ directories for memory and nodes? We have linkages > there for each memory section to every NUMA node, and you can also > derive the physical address from the phys_index in each section. That > should allow you to work out physical addresses for a given node. > I had looked at the memory-hotplug interface but found that this 'phys_index' doesn't include holes, while ->node_spanned_pages does. Thanks, Davidlohr -- 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