From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id EA4E06B01E3 for ; Fri, 23 Apr 2010 03:00:19 -0400 (EDT) Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [202.81.31.245]) by e23smtp03.au.ibm.com (8.14.3/8.13.1) with ESMTP id o3N6uuau005585 for ; Fri, 23 Apr 2010 16:56:56 +1000 Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o3N70D9O1630298 for ; Fri, 23 Apr 2010 17:00:13 +1000 Received: from d23av01.au.ibm.com (loopback [127.0.0.1]) by d23av01.au.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o3N70DmU017121 for ; Fri, 23 Apr 2010 17:00:13 +1000 Date: Fri, 23 Apr 2010 12:30:11 +0530 From: Balbir Singh Subject: Re: [BUGFIX][PATCH] memcg rcu lock fix v3 Message-ID: <20100423070011.GS3994@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <4BD10D59.9090504@cn.fujitsu.com> <20100423121424.ae47efcb.kamezawa.hiroyu@jp.fujitsu.com> <4BD118E2.7080307@cn.fujitsu.com> <4BD11A24.2070500@cn.fujitsu.com> <20100423125814.01e95bce.kamezawa.hiroyu@jp.fujitsu.com> <20100423130349.f320d0be.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20100423130349.f320d0be.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: Li Zefan , Daisuke Nishimura , "Paul E. McKenney" , "linux-mm@kvack.org" , LKML , "akpm@linux-foundation.org" List-ID: * KAMEZAWA Hiroyuki [2010-04-23 13:03:49]: > On Fri, 23 Apr 2010 12:58:14 +0900 > KAMEZAWA Hiroyuki wrote: > > > On Fri, 23 Apr 2010 11:55:16 +0800 > > Li Zefan wrote: > > > > > Li Zefan wrote: > > > > KAMEZAWA Hiroyuki wrote: > > > >> On Fri, 23 Apr 2010 11:00:41 +0800 > > > >> Li Zefan wrote: > > > >> > > > >>> with CONFIG_PROVE_RCU=y, I saw this warning, it's because > > > >>> css_id() is not under rcu_read_lock(). > > > >>> > > > >> Ok. Thank you for reporting. > > > >> This is ok ? > > > > > > > > Yes, and I did some more simple tests on memcg, no more warning > > > > showed up. > > > > > > > > > > oops, after trigging oom, I saw 2 more warnings: > > > > > > > Thank you for good testing. > v3 here...sorry too rapid posting... > Looking at the patch we seem to be protecting the use of only css_*(). I wonder if we should push down the rcu_read_*lock() semnatics to the css routines or is it just too instrusive to do it that way? -- Three Cheers, Balbir -- 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