From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946873AbdEZDrR (ORCPT ); Thu, 25 May 2017 23:47:17 -0400 Received: from mail-pf0-f194.google.com ([209.85.192.194]:35907 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1946827AbdEZDqw (ORCPT ); Thu, 25 May 2017 23:46:52 -0400 Date: Fri, 26 May 2017 13:46:36 +1000 From: Balbir Singh To: Reza Arbab Cc: Michael Ellerman , Michael Bringmann , linux-kernel@vger.kernel.org, Paul Mackerras , "Aneesh Kumar K.V" , Bharata B Rao , Shailendra Singh , Thomas Gleixner , linuxppc-dev@lists.ozlabs.org, Sebastian Andrzej Siewior Subject: Re: [Patch 2/2]: powerpc/hotplug/mm: Fix hot-add memory node assoc Message-ID: <20170526134636.03548feb@firefly.ozlabs.ibm.com> In-Reply-To: <20170525151011.m4ae4ipxbqsj3mn7@arbab-laptop.localdomain> References: <3bb44d92-b2ff-e197-4bdf-ec6d588d6dab@linux.vnet.ibm.com> <20170523155251.bqwc5mc4jpgzkqlm@arbab-laptop.localdomain> <1c1d70e3-4e45-b035-0e75-1b0f531c111b@linux.vnet.ibm.com> <20170523214922.bns675oqzqj4pkhc@arbab-laptop.localdomain> <87poeya4dt.fsf@concordia.ellerman.id.au> <8e2417d8-d108-2949-40f2-997d53a3f367@linux.vnet.ibm.com> <87a861a25y.fsf@concordia.ellerman.id.au> <20170525151011.m4ae4ipxbqsj3mn7@arbab-laptop.localdomain> X-Mailer: Claws Mail 3.14.1 (GTK+ 2.24.31; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 25 May 2017 10:10:11 -0500 Reza Arbab wrote: > On Thu, May 25, 2017 at 04:19:53PM +1000, Michael Ellerman wrote: > >The commit message for 3af229f2071f says: > > > > In practice, we never see a system with 256 NUMA nodes, and in fact, we > > do not support node hotplug on power in the first place, so the nodes > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > that are online when we come up are the nodes that will be present for > > the lifetime of this kernel. > > > >Is that no longer true? > > I don't know what the reasoning behind that statement was at the time, > but as far as I can tell, the only thing missing for node hotplug now is > Balbir's patchset [1]. He fixes the resource issue which motivated > 3af229f2071f and reverts it. > > With that set, I can instantiate a new numa node just by doing > add_memory(nid, ...) where nid doesn't currently exist. > > [1] https://lkml.kernel.org/r/1479253501-26261-1-git-send-email-bsingharora@gmail.com > I guess I should try and revive that patchset. One of the suggestions of then was to limit maximum possible nodes in firmware, but I'm double checking to see if we can do that in a well defined manner. Balbir Singh