From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e3.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id l6PEkXpj022817 for ; Wed, 25 Jul 2007 10:46:33 -0400 Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v8.4) with ESMTP id l6PFokro557354 for ; Wed, 25 Jul 2007 11:50:46 -0400 Received: from d01av01.pok.ibm.com (loopback [127.0.0.1]) by d01av01.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l6PFokEV027390 for ; Wed, 25 Jul 2007 11:50:46 -0400 Date: Wed, 25 Jul 2007 08:50:44 -0700 From: Nishanth Aravamudan Subject: Re: [PATCH take2] Memoryless nodes: use "node_memory_map" for cpuset mems_allowed validation Message-ID: <20070725155044.GD18510@us.ibm.com> References: <20070711182219.234782227@sgi.com> <20070711182250.005856256@sgi.com> <1185286525.5649.27.camel@localhost> <20070724161925.GB18510@us.ibm.com> <1185303693.5649.45.camel@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1185303693.5649.45.camel@localhost> Sender: owner-linux-mm@kvack.org Return-Path: To: Lee Schermerhorn Cc: Christoph Lameter , Paul Jackson , akpm@linux-foundation.org, kxr@sgi.com, linux-mm@kvack.org, KAMEZAWA Hiroyuki List-ID: On 24.07.2007 [15:01:33 -0400], Lee Schermerhorn wrote: > On Tue, 2007-07-24 at 09:19 -0700, Nishanth Aravamudan wrote: > > On 24.07.2007 [10:15:25 -0400], Lee Schermerhorn wrote: > > > Memoryless Nodes: use "node_memory_map" for cpusets - take 2 > > > > > > Against 2.6.22-rc6-mm1 atop Christoph Lameter's memoryless nodes > > > series > > > > > > take 2: > > > + replaced node_online_map in cpuset_current_mems_allowed() > > > with node_states[N_MEMORY] > > > + replaced node_online_map in cpuset_init_smp() with > > > node_states[N_MEMORY] > > > > > > cpusets try to ensure that any node added to a cpuset's > > > mems_allowed is on-line and contains memory. The assumption > > > was that online nodes contained memory. Thus, it is possible > > > to add memoryless nodes to a cpuset and then add tasks to this > > > cpuset. This results in continuous series of oom-kill and > > > apparent system hang. > > > > > > Change cpusets to use node_states[N_MEMORY] [a.k.a. > > > node_memory_map] in place of node_online_map when vetting > > > memories. Return error if admin attempts to write a non-empty > > > mems_allowed node mask containing only memoryless-nodes. > > > > I think you still are missing a few comment changes (anything mentioning > > 'track'ing node_online_map will need to be changed, I think). Also, I > > don't see the necessary change in common_cpu_mem_hotplug_unplug() > > similar to cpuset_init_smp()'s change. > > Sorry. Multitasking meltdown... Will fix. > > Meanwhile: > > I've tested your 3 patches atop Christoph's series [on 22-rc6-mm1], > with and without my cpuset patch and I can't reproduce the hang I saw > a couple of days ago :-(. I hate it when that happens! Perhaps some > system daemon started up during the test that hung. Hrm, that stinks. I tested on several h/w variations before posting. And the changes are pretty transparent, so I'm not sure where we'd hang (and I would think if we were, we'd see it now too). But I'll do another audit just to be sure. Thanks, Nish -- Nishanth Aravamudan IBM Linux Technology Center -- 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