Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933337AbaGURdw (ORCPT ); Mon, 21 Jul 2014 13:33:52 -0400 Received: from e39.co.us.ibm.com ([32.97.110.160]:59761 "EHLO e39.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932647AbaGURdu (ORCPT ); Mon, 21 Jul 2014 13:33:50 -0400 Date: Mon, 21 Jul 2014 10:33:42 -0700 From: "Paul E. McKenney" To: Nishanth Aravamudan Cc: Jiang Liu , Andrew Morton , Mel Gorman , David Rientjes , Mike Galbraith , Peter Zijlstra , "Rafael J . Wysocki" , Dipankar Sarma , Balbir Singh , Thomas Gleixner , Jens Axboe , Frederic Weisbecker , Jan Kara , Ingo Molnar , Christoph Hellwig , "Srivatsa S. Bhat" , Roman Gushchin , Xie XiuQi , Tony Luck , linux-mm@kvack.org, linux-hotplug@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC Patch V1 01/30] mm, kernel: Use cpu_to_mem()/numa_mem_id() to support memoryless node Message-ID: <20140721173342.GB8690@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <1405064267-11678-1-git-send-email-jiang.liu@linux.intel.com> <1405064267-11678-2-git-send-email-jiang.liu@linux.intel.com> <20140711151405.GK16041@linux.vnet.ibm.com> <20140721171527.GA4156@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140721171527.GA4156@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14072117-9332-0000-0000-00000173DD54 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 21, 2014 at 10:15:27AM -0700, Nishanth Aravamudan wrote: > Hi Paul, > > On 11.07.2014 [08:14:05 -0700], Paul E. McKenney wrote: > > On Fri, Jul 11, 2014 at 03:37:18PM +0800, Jiang Liu wrote: > > > When CONFIG_HAVE_MEMORYLESS_NODES is enabled, cpu_to_node()/numa_node_id() > > > may return a node without memory, and later cause system failure/panic > > > when calling kmalloc_node() and friends with returned node id. > > > So use cpu_to_mem()/numa_mem_id() instead to get the nearest node with > > > memory for the/current cpu. > > > > > > If CONFIG_HAVE_MEMORYLESS_NODES is disabled, cpu_to_mem()/numa_mem_id() > > > is the same as cpu_to_node()/numa_node_id(). > > > > > > Signed-off-by: Jiang Liu > > > > For the rcutorture piece: > > > > Acked-by: Paul E. McKenney > > > > Or if you separate the kernel/rcu/rcutorture.c portion into a separate > > patch, I will queue it separately. > > Just FYI, based upon a separate discussion with Tejun and others, it > seems to be preferred to avoid the proliferation of cpu_to_mem > throughout the kernel blindly. For kthread_create_on_node(), I'm going > to try and fix the underlying issue and so you, as the caller, should > still specify the NUMA node you are running the kthread on > (cpu_to_node), not where you expect the memory to come from > (cpu_to_mem). Even better!!! ;-) Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/