From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f45.google.com (mail-qg0-f45.google.com [209.85.192.45]) by kanga.kvack.org (Postfix) with ESMTP id 53B676B003C for ; Mon, 21 Jul 2014 13:15:37 -0400 (EDT) Received: by mail-qg0-f45.google.com with SMTP id f51so5644840qge.32 for ; Mon, 21 Jul 2014 10:15:37 -0700 (PDT) Received: from e8.ny.us.ibm.com (e8.ny.us.ibm.com. [32.97.182.138]) by mx.google.com with ESMTPS id w35si28978388qge.36.2014.07.21.10.15.36 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 21 Jul 2014 10:15:36 -0700 (PDT) Received: from /spool/local by e8.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 21 Jul 2014 13:15:36 -0400 Received: from b01cxnp22036.gho.pok.ibm.com (b01cxnp22036.gho.pok.ibm.com [9.57.198.26]) by d01dlp03.pok.ibm.com (Postfix) with ESMTP id 348B6C90062 for ; Mon, 21 Jul 2014 13:15:25 -0400 (EDT) Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by b01cxnp22036.gho.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s6LHFWvM4522364 for ; Mon, 21 Jul 2014 17:15:32 GMT Received: from d01av01.pok.ibm.com (localhost [127.0.0.1]) by d01av01.pok.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s6LHFUY2026018 for ; Mon, 21 Jul 2014 13:15:31 -0400 Date: Mon, 21 Jul 2014 10:15:27 -0700 From: Nishanth Aravamudan Subject: Re: [RFC Patch V1 01/30] mm, kernel: Use cpu_to_mem()/numa_mem_id() to support memoryless node Message-ID: <20140721171527.GA4156@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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140711151405.GK16041@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Paul E. McKenney" 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 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). Thanks, Nish -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org