From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753412AbcITAya (ORCPT ); Mon, 19 Sep 2016 20:54:30 -0400 Received: from mail-pf0-f177.google.com ([209.85.192.177]:34301 "EHLO mail-pf0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752611AbcITAy3 (ORCPT ); Mon, 19 Sep 2016 20:54:29 -0400 Date: Mon, 19 Sep 2016 17:54:26 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Anshuman Khandual cc: Dave Hansen , linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org Subject: Re: [PATCH V4] mm: Add sysfs interface to dump each node's zonelist information In-Reply-To: <57DCC605.10305@linux.vnet.ibm.com> Message-ID: References: <1473150666-3875-1-git-send-email-khandual@linux.vnet.ibm.com> <1473302818-23974-1-git-send-email-khandual@linux.vnet.ibm.com> <57D1C914.9090403@intel.com> <57D63CB2.8070003@linux.vnet.ibm.com> <57DCC605.10305@linux.vnet.ibm.com> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 17 Sep 2016, Anshuman Khandual wrote: > > I'm questioning if this information can be inferred from information > > already in /proc/zoneinfo and sysfs. We know the no-fallback zonelist is > > going to include the local node, and we know the other zonelists are > > either node ordered or zone ordered (or do we need to extend > > vm.numa_zonelist_order for default?). I may have missed what new > > knowledge this interface is imparting on us. > > IIUC /proc/zoneinfo lists down zone internal state and statistics for > all zones on the system at any given point of time. The no-fallback > list contains the zones from the local node and fallback (which gets > used more often than the no-fallback) list contains all zones either > in node-ordered or zone-ordered manner. In most of the platforms the > default being the node order but the sequence of present nodes in > that order is determined by various factors like NUMA distance, load, > presence of CPUs on the node etc. This order of nodes in the fallback > list is the most important information derived out of this interface. > The point is that all of this can be inferred with information already provided, so the additional interface seems unnecessary. The only extension I think that is needed is to determine if the order is node or zone when vm.numa_zonelist_order == default and we shouldn't parse this from dmesg.