From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754128Ab0C0WqP (ORCPT ); Sat, 27 Mar 2010 18:46:15 -0400 Received: from e8.ny.us.ibm.com ([32.97.182.138]:55429 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754099Ab0C0WqO (ORCPT ); Sat, 27 Mar 2010 18:46:14 -0400 Date: Sat, 27 Mar 2010 15:46:06 -0700 From: "Paul E. McKenney" To: Mathieu Desnoyers Cc: akpm@linux-foundation.org, Ingo Molnar , linux-kernel@vger.kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com, josh@joshtriplett.org, dvhltc@us.ibm.com, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, adobriyan@gmail.com Subject: Re: [patch 0/6] rcu head debugobjects Message-ID: <20100327224606.GK2343@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20100327153233.993367557@efficios.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100327153233.993367557@efficios.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Mar 27, 2010 at 11:32:33AM -0400, Mathieu Desnoyers wrote: > Hi, > > Here is an updated version of the rcu head debugobjects, following the comments > I received in the last rounds. > > It applies on top of -tip, based on 2.6.34-rc2, commit > 2e958f219d2b8d192d44e2472a214b3a93c44673 > > Unless people have any objection, it should be ready to be merged. I think the > appropriate maintainer to perform this merge would be Paul E. McKenney, because > this patchset is RCU-related. This should be very helpful in tracking down otherwise-painful bugs!!! Thank you, Mathieu!!! I am happy to apply this, especially given Dave Miller's Acked-by. A few questions and comments: o Patches 1/6, 2/6, 3/6: Was the intent for the three Subject lines to read as follows? [patch 1/6] Revert "net: remove INIT_RCU_HEAD() usage" [patch 2/6] Revert "netfilter: don't use INIT_RCU_HEAD()" [patch 3/6] Revert "net: don't use INIT_RCU_HEAD" o Patch 4/6 looks good to me, and given that Thomas hasn't complained, I am guessing that he is OK with it. o Would it be possible to make this bisectable as follows? a. Insert a new patch after current patch 4/6 that defines destroy_rcu_head_on_stack(), rcu_head_init_on_stack(), and rcu_head_init() with their !CONFIG_DEBUG_OBJECTS_RCU_HEAD definitions. b. Move current patch 6/6 to this position. c. Move current patch 5/6 to this position, updating to reflect the new patch added in (a) above. o Patch 6/6: Would it be possible to use the object_is_on_stack() function defined in include/linux/sched.h instead of passing in the flag on_stack to bdi_work_init()? It looks like fs/fs-writeback.c already includes include/linux/sched.h, so shouldn't be a problem from a #include-hell viewpoint. Please let me know if I am missing something on any of the above. If these changes seem reasonable to you, please either submit a new patch set or let me know that you are OK with me making these changes. Thanx, Paul