From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id 28AED6B009A for ; Fri, 24 Jul 2009 23:15:19 -0400 (EDT) Received: from m3.gw.fujitsu.co.jp ([10.0.50.73]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n6P3FCvC021438 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Sat, 25 Jul 2009 12:15:12 +0900 Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id D451045DE52 for ; Sat, 25 Jul 2009 12:15:11 +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 AC88945DE50 for ; Sat, 25 Jul 2009 12:15:11 +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 896311DB8040 for ; Sat, 25 Jul 2009 12:15:11 +0900 (JST) Received: from ml11.s.css.fujitsu.com (ml11.s.css.fujitsu.com [10.249.87.101]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 342581DB803E for ; Sat, 25 Jul 2009 12:15:11 +0900 (JST) Message-ID: <9443f91bd4648e6214b32acff4512b97.squirrel@webmail-b.css.fujitsu.com> In-Reply-To: <5bb65c0e4c6828b1331d33745f34d9ee.squirrel@webmail-b.css.fujitsu.com> 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> Date: Sat, 25 Jul 2009 12:15:10 +0900 (JST) Subject: Re: [BUG] set_mempolicy(MPOL_INTERLEAV) cause kernel panic From: "KAMEZAWA Hiroyuki" MIME-Version: 1.0 Content-Type: text/plain;charset=iso-2022-jp Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: Andrew Morton , David Rientjes , lee.schermerhorn@hp.com, kosaki.motohiro@jp.fujitsu.com, miaox@cn.fujitsu.com, mingo@elte.hu, a.p.zijlstra@chello.nl, cl@linux-foundation.org, menage@google.com, nickpiggin@yahoo.com.au, y-goto@jp.fujitsu.com, penberg@cs.helsinki.fi, linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: KAMEZAWA Hiroyuki wrote: > KAMEZAWA Hiroyuki wrote: > Then, here is a much easier fix. for trusting cpuset more. > just a memo about memory hotplug _Direct_ use of task->mems_allowed is only in cpuset and mempolicy. If no policy is used, it's not checked. (See alloc_pages_current()) memory hotplug's notifier just updates top_cpuset's mems_allowed. But it doesn't update each task's ones. Then, task's bahavior is - tasks which don't use mempolicy will use all nodes, N_HIGH_MEMORY. - tasks under cpuset will be controlled under their own cpuset. - tasks under mempolicy will use their own policy. but no new policy is re-calculated and, then, no new mask. Now, even if all memory on nodes a removed, pgdat just remains. Then, cpuset/mempolicy will never access NODE_DATA(nid) which is NULL. 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