From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id E00636B0055 for ; Mon, 27 Jul 2009 20:27:22 -0400 (EDT) Received: from m3.gw.fujitsu.co.jp ([10.0.50.73]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n6S0RUgo018187 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Tue, 28 Jul 2009 09:27:30 +0900 Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id 02D7745DE4F for ; Tue, 28 Jul 2009 09:27:30 +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 C47A545DE4E for ; Tue, 28 Jul 2009 09:27:29 +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 77CE11DB8038 for ; Tue, 28 Jul 2009 09:27:29 +0900 (JST) Received: from m107.s.css.fujitsu.com (m107.s.css.fujitsu.com [10.249.87.107]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id C2BB31DB803E for ; Tue, 28 Jul 2009 09:27:28 +0900 (JST) Date: Tue, 28 Jul 2009 09:25:29 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [BUG] set_mempolicy(MPOL_INTERLEAV) cause kernel panic Message-Id: <20090728092529.bb0d7e9c.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20090715182320.39B5.A69D9226@jp.fujitsu.com> <1247679064.4089.26.camel@useless.americas.hpqcorp.net> <20090724160936.a3b8ad29.akpm@linux-foundation.org> <337c5d83954b38b14a17f0adf4d357d8.squirrel@webmail-b.css.fujitsu.com> <5bb65c0e4c6828b1331d33745f34d9ee.squirrel@webmail-b.css.fujitsu.com> <9443f91bd4648e6214b32acff4512b97.squirrel@webmail-b.css.fujitsu.com> <20090728085810.f7ae678a.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: David Rientjes Cc: Andrew Morton , Lee Schermerhorn , KOSAKI Motohiro , miaox@cn.fujitsu.com, Ingo Molnar , Peter Zijlstra , Christoph Lameter , Paul Menage , Nick Piggin , y-goto@jp.fujitsu.com, Pekka Enberg , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Mon, 27 Jul 2009 17:14:32 -0700 (PDT) David Rientjes wrote: > On Tue, 28 Jul 2009, KAMEZAWA Hiroyuki wrote: > > > > The nodemask for each task is updated to reflect the removal of a node and > > > it calls mpol_rebind_mm() with the new nodemask. > > > > > yes, but _not_ updated at online. > > > > Well, I disagreed that we needed to alter any pre-existing mempolicies for > MEM_GOING_ONLINE or MEM_ONLINE since it may diverge from the original > intent of the policy. MPOL_PREFERRED certain shouldn't change, > MPOL_INTERLEAVE would be unbalanced, and MPOL_BIND could diverge from > memory isolation or affinity requirements. > > I'd be interested to hear any real world use cases for MEM_ONLINE updating > of mempolicies. > Sorry, I was a bit condused. I thought I said about task->mems_allowed. Not each policy. Because we dont' update, task->mems_allowed need to be initilaized as N_POSSIBLE_NODES. At usual thinking, it should be N_HIGH_MEMORY or N_ONLINE_NODES, as my patch does. > > What I felt at reading cpuset/mempolicy again is that it's too complex ;) > > The 1st question is why mems_allowed which can be 1024bytes when max_node=4096 > > is copied per tasks.... > > The page allocator needs lockless access to mems_allowed. > Hmm, ok, I'll take care of that. Thanks, -Kame -- 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