Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756119Ab0DWHAT (ORCPT ); Fri, 23 Apr 2010 03:00:19 -0400 Received: from e23smtp06.au.ibm.com ([202.81.31.148]:49493 "EHLO e23smtp06.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756092Ab0DWHAQ (ORCPT ); Fri, 23 Apr 2010 03:00:16 -0400 Date: Fri, 23 Apr 2010 12:30:11 +0530 From: Balbir Singh To: KAMEZAWA Hiroyuki Cc: Li Zefan , Daisuke Nishimura , "Paul E. McKenney" , "linux-mm@kvack.org" , LKML , "akpm@linux-foundation.org" 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> User-Agent: Mutt/1.5.20 (2009-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1339 Lines: 42 * 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 from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/