From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754548AbbAWVJ0 (ORCPT ); Fri, 23 Jan 2015 16:09:26 -0500 Received: from resqmta-ch2-09v.sys.comcast.net ([69.252.207.41]:57840 "EHLO resqmta-ch2-09v.sys.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752722AbbAWVJW (ORCPT ); Fri, 23 Jan 2015 16:09:22 -0500 Date: Fri, 23 Jan 2015 15:09:20 -0600 (CST) From: Christoph Lameter X-X-Sender: cl@gentwo.org To: Guenter Roeck cc: Johannes Weiner , akpm@linux-foundation.org, mm-commits@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-next@vger.kernel.org, sfr@canb.auug.org.au, mhocko@suse.cz Subject: Re: mmotm 2015-01-22-15-04: qemu failure due to 'mm: memcontrol: remove unnecessary soft limit tree node test' In-Reply-To: <54C2B01D.4070303@roeck-us.net> Message-ID: References: <54c1822d.RtdGfWPekQVAw8Ly%akpm@linux-foundation.org> <20150123050802.GB22751@roeck-us.net> <20150123141817.GA22926@phnom.home.cmpxchg.org> <54C2B01D.4070303@roeck-us.net> 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 Fri, 23 Jan 2015, Guenter Roeck wrote: > Wouldn't that have unintended consequences ? So far > rb tree nodes are allocated even if a node not online; > the above would change that. Are you saying it is > unnecessary to initialize rb tree nodes if the node > is not online ? It is not advisable to allocate since an offline node means that the structure cannot be allocated on the node where it would be most beneficial. Typically subsystems allocate the per node data structures when the node is brought online. > Not that I have any idea what is correct, it just seems odd > that the existing code would do all this allocation if it is not > necessary. Not sure how the code there works just guessing from other subsystems.