From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753353AbYLSBt6 (ORCPT ); Thu, 18 Dec 2008 20:49:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751644AbYLSBtu (ORCPT ); Thu, 18 Dec 2008 20:49:50 -0500 Received: from e3.ny.us.ibm.com ([32.97.182.143]:54690 "EHLO e3.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750789AbYLSBtt (ORCPT ); Thu, 18 Dec 2008 20:49:49 -0500 Date: Thu, 18 Dec 2008 17:49:46 -0800 From: "Paul E. McKenney" To: Andi Kleen Cc: linux-kernel@vger.kernel.org, cl@linux-foundation.org, mingo@elte.hu, akpm@linux-foundation.org, manfred@colorfullife.com, dipankar@in.ibm.com, josht@linux.vnet.ibm.com, schamp@sgi.com, niv@us.ibm.com, dvhltc@us.ibm.com, ego@in.ibm.com, laijs@cn.fujitsu.com, rostedt@goodmis.org, peterz@infradead.org, penberg@cs.helsinki.fi, tglx@linutronix.de Subject: Re: [PATCH -tip] v9 scalable classic RCU implementation Message-ID: <20081219014946.GJ6912@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20081202222157.GA14911@linux.vnet.ibm.com> <20081202233144.GE6703@one.firstfloor.org> <20081202235145.GF6719@linux.vnet.ibm.com> <20081203001811.GF6703@one.firstfloor.org> <20081203004759.GG6719@linux.vnet.ibm.com> <20081203011042.GH6703@one.firstfloor.org> <20081203013659.GH6719@linux.vnet.ibm.com> <20081218225403.GA24881@linux.vnet.ibm.com> <20081219012935.GO25779@one.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081219012935.GO25779@one.firstfloor.org> User-Agent: Mutt/1.5.15+20070412 (2007-04-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 19, 2008 at 02:29:35AM +0100, Andi Kleen wrote: > On Thu, Dec 18, 2008 at 02:54:03PM -0800, Paul E. McKenney wrote: > > On Tue, Dec 02, 2008 at 05:36:59PM -0800, Paul E. McKenney wrote: > > > On Wed, Dec 03, 2008 at 02:10:42AM +0100, Andi Kleen wrote: > > > > > On Power, I see a hang in all three flavors of RCU when CPU hotplug > > > > > is enabled and dynticks is not. I have not yet seen this hang on x86. > > > > > On Power, the hang occurs in the CPU-offline code, and is identical to > > > > > the hangs I was seeing in 2.6.27, except that "sleep 1" does not hang > > > > > in recent 2.6.28 versions. So the timeout is apparently failing to fire > > > > > (or being ignored) for some other reason. > > > > > > > > > > Is this similar to what you are seeing on x86? > > > > > > > > Yes it is. > > > > > > OK, then I will consider them to be the same bug for the moment. > > > > Question based on some further testing over here... > > > > Do you still get failures if you refrain from offlining CPU 0? > > Yes, i never offlined cpu 0 in fact. Hmmm... Then you are most likely seeing a different failure than I see on Power. Could you please retry with v10 of the patch, setting CONFIG_TREE_RCU? Thanx, Paul