From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754479AbYI3Pw7 (ORCPT ); Tue, 30 Sep 2008 11:52:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753749AbYI3Pwt (ORCPT ); Tue, 30 Sep 2008 11:52:49 -0400 Received: from tomts10.bellnexxia.net ([209.226.175.54]:55442 "EHLO tomts10-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753145AbYI3Pws (ORCPT ); Tue, 30 Sep 2008 11:52:48 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ArgEALHl4UhMQWq+/2dsb2JhbACBZL0KgWc Date: Tue, 30 Sep 2008 11:52:45 -0400 From: Mathieu Desnoyers To: Ingo Molnar Cc: Andrew Morton , "Paul E. McKenney" , Linux Kernel Mailing List , Steven Rostedt , Peter Zijlstra , Rusty Russell , "Frank Ch. Eigler" , Lai Jiangshan Subject: Re: [PATCH] Markers : fix reentrancy Message-ID: <20080930155245.GC12623@Krystal> References: <20080930054151.GA16961@Krystal> <20080930070923.GB30927@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <20080930070923.GB30927@elte.hu> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.21.3-grsec (i686) X-Uptime: 11:43:02 up 117 days, 20:23, 8 users, load average: 0.36, 0.38, 0.36 User-Agent: Mutt/1.5.16 (2007-06-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Ingo Molnar (mingo@elte.hu) wrote: > > * Mathieu Desnoyers wrote: > > > Lai Jiangshan wrote : > > > marker_synchronize_unregister must be called _also_ between unregistration > > > and destruction the data that unregistration-ed probes need to make sure > > > there is no caller executing a probe when it's data is destroyed. > > > > > > > Ah, you're right. I looked again through your patch description and I > > think using a : > > > > > > if (entry->rcu_pending) > > rcu_barrier_sched(); > > > > After each time the markers_mutex is taken would keep the fast batch > > registration/unregistration and fix the reentrancy problem. The > > following patch should address the problem. > > could you please send a delta patch against tip/master? Lai's patch is > already applied and is tested. Thanks, > > Ingo Hrm, Most of Lai "simplifications" to use synchronize_sched() instead of call_rcu_sched() will make batch registration/unregistration much slower (very noticeable on ~50 markers on a loaded machine). It also contains two different fixes in one, one of which has been nacked. The correct list of changes against tip now becomes : Revert commit d587284c1d26b796bf52a6e3d3f783db4e462119 Apply patch "Markers : marker_synchronize_unregister()" Apply patch "Markers : probe example fix teardown" Apply patch "Markers : documentation fix teardown" Apply patch "sputrace : use marker_synchronize_unregister()" Apply patch "Markers : fix reentrancy" Sorry, but rebasing those marker fixes will just make all those changes really messy. I think the cleanest way is to just revert. :-/ Mathieu -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68