From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id C384F6B004F for ; Thu, 16 Jul 2009 22:07:12 -0400 (EDT) Received: from m3.gw.fujitsu.co.jp ([10.0.50.73]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n6H27CG7004840 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Fri, 17 Jul 2009 11:07:12 +0900 Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id 3D46245DE57 for ; Fri, 17 Jul 2009 11:07:12 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.fujitsu.co.jp [10.0.50.93]) by m3.gw.fujitsu.co.jp (Postfix) with ESMTP id 118D145DE55 for ; Fri, 17 Jul 2009 11:07:12 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id D879D1DB8041 for ; Fri, 17 Jul 2009 11:07:11 +0900 (JST) Received: from m106.s.css.fujitsu.com (m106.s.css.fujitsu.com [10.249.87.106]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 3DC671DB8045 for ; Fri, 17 Jul 2009 11:07:11 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [BUG] set_mempolicy(MPOL_INTERLEAV) cause kernel panic In-Reply-To: <20090717095745.1d3039b1.kamezawa.hiroyu@jp.fujitsu.com> References: <20090717090003.A903.A69D9226@jp.fujitsu.com> <20090717095745.1d3039b1.kamezawa.hiroyu@jp.fujitsu.com> Message-Id: <20090717104512.A914.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Fri, 17 Jul 2009 11:07:09 +0900 (JST) Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: kosaki.motohiro@jp.fujitsu.com, David Rientjes , Lee Schermerhorn , Miao Xie , Ingo Molnar , Peter Zijlstra , Christoph Lameter , Paul Menage , Nick Piggin , Yasunori Goto , Pekka Enberg , linux-mm , LKML , Andrew Morton List-ID: > On Fri, 17 Jul 2009 09:04:46 +0900 (JST) > KOSAKI Motohiro wrote: > > > > On Wed, 15 Jul 2009, Lee Schermerhorn wrote: > > > > > > > Interestingly, on ia64, the top cpuset mems_allowed gets set to all > > > > possible nodes, while on x86_64, it gets set to on-line nodes [or nodes > > > > with memory]. Maybe this is a to support hot-plug? > > > > > > > > > > numactl --interleave=all simply passes a nodemask with all bits set, so if > > > cpuset_current_mems_allowed includes offline nodes from node_possible_map, > > > then mpol_set_nodemask() doesn't mask them off. > > > > > > Seems like we could handle this strictly in mempolicies without worrying > > > about top_cpuset like in the following? > > > > This patch seems band-aid patch. it will change memory-hotplug behavior. > > Please imazine following scenario: > > > > 1. numactl interleave=all process-A > > 2. memory hot-add > > > > before 2.6.30: > > -> process-A can use hot-added memory > > > > your proposal patch: > > -> process-A can't use hot-added memory > > > > IMHO, the application itseld should be notifed to change its mempolicy by > hot-plug script on the host. While an application uses interleave, a new node > hot-added is just a noise. I think "How pages are interleaved" should not be > changed implicitly. Then, checking at set_mempolicy() seems sane. If notified, > application can do page migration and rebuild his mapping in ideal way. Do you really want ABI change? > BUT I don't linke init->mem_allowed contains N_POSSIBLE...it should be initialized > to N_HIGH_MEMORY, IMHO. -- 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