Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755644AbcJTDbH (ORCPT ); Wed, 19 Oct 2016 23:31:07 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:35550 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752738AbcJTDbG (ORCPT ); Wed, 19 Oct 2016 23:31:06 -0400 Subject: Re: [PATCH v4 3/5] powerpc/mm: allow memory hotplug into a memoryless node To: Reza Arbab , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Rob Herring , Frank Rowand , Andrew Morton References: <1475778995-1420-1-git-send-email-arbab@linux.vnet.ibm.com> <1475778995-1420-4-git-send-email-arbab@linux.vnet.ibm.com> Cc: Bharata B Rao , Nathan Fontenot , Stewart Smith , Alistair Popple , "Aneesh Kumar K.V" , Tang Chen , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, devicetree@vger.kernel.org, linux-mm@kvack.org From: Balbir Singh Message-ID: <872f253d-8a55-246c-2be0-636a588e2dd0@gmail.com> Date: Thu, 20 Oct 2016 14:30:42 +1100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.0 MIME-Version: 1.0 In-Reply-To: <1475778995-1420-4-git-send-email-arbab@linux.vnet.ibm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1863 Lines: 58 On 07/10/16 05:36, Reza Arbab wrote: > Remove the check which prevents us from hotplugging into an empty node. > > This limitation has been questioned before [1], and judging by the > response, there doesn't seem to be a reason we can't remove it. No issues > have been found in light testing. > > [1] http://lkml.kernel.org/r/CAGZKiBrmkSa1yyhbf5hwGxubcjsE5SmkSMY4tpANERMe2UG4bg@mail.gmail.com > http://lkml.kernel.org/r/20160511215051.GF22115@arbab-laptop.austin.ibm.com > > Signed-off-by: Reza Arbab > Reviewed-by: Aneesh Kumar K.V > Acked-by: Balbir Singh > Cc: Nathan Fontenot > Cc: Bharata B Rao > --- > arch/powerpc/mm/numa.c | 13 +------------ > 1 file changed, 1 insertion(+), 12 deletions(-) > > diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c > index 75b9cd6..d7ac419 100644 > --- a/arch/powerpc/mm/numa.c > +++ b/arch/powerpc/mm/numa.c > @@ -1121,7 +1121,7 @@ static int hot_add_node_scn_to_nid(unsigned long scn_addr) > int hot_add_scn_to_nid(unsigned long scn_addr) > { > struct device_node *memory = NULL; > - int nid, found = 0; > + int nid; > > if (!numa_enabled || (min_common_depth < 0)) > return first_online_node; > @@ -1137,17 +1137,6 @@ int hot_add_scn_to_nid(unsigned long scn_addr) > if (nid < 0 || !node_online(nid)) > nid = first_online_node; > > - if (NODE_DATA(nid)->node_spanned_pages) > - return nid; > - > - for_each_online_node(nid) { > - if (NODE_DATA(nid)->node_spanned_pages) { > - found = 1; > - break; > - } > - } > - > - BUG_ON(!found); > return nid; FYI, these checks were temporary to begin with I found this in git history b226e462124522f2f23153daff31c311729dfa2f (powerpc: don't add memory to empty node/zone) Balbir Singh.