From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264824AbUEQCNd (ORCPT ); Sun, 16 May 2004 22:13:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264835AbUEQCNd (ORCPT ); Sun, 16 May 2004 22:13:33 -0400 Received: from taco.zianet.com ([216.234.192.159]:50188 "HELO taco.zianet.com") by vger.kernel.org with SMTP id S264824AbUEQCN1 (ORCPT ); Sun, 16 May 2004 22:13:27 -0400 From: Steven Cole To: Andrea Arcangeli Subject: Re: 1352 NUL bytes at the end of a page? (was Re: Assertion `s && s->tree' failed: The saga continues.) Date: Sun, 16 May 2004 20:12:56 -0600 User-Agent: KMail/1.6.1 Cc: Andrew Morton , torvalds@osdl.org, adi@bitmover.com, scole@lanl.gov, support@bitmover.com, linux-kernel@vger.kernel.org References: <200405132232.01484.elenstev@mesatop.com> <200405161611.17688.elenstev@mesatop.com> <20040516235310.GZ3044@dualathlon.random> In-Reply-To: <20040516235310.GZ3044@dualathlon.random> MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200405162012.57066.elenstev@mesatop.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sunday 16 May 2004 05:53 pm, Andrea Arcangeli wrote: > On Sun, May 16, 2004 at 04:11:16PM -0600, Steven Cole wrote: > > On Sunday 16 May 2004 03:29 pm, Andrew Morton wrote: > > > Steven Cole wrote: > > > > > > > > Anyway, although the regression for my particular machine for this > > > > particular load may be interesting, the good news is that I've seen > > > > none of the failures which started this whole thread, which are relatively > > > > easily reproduceable with PREEMPT set. > > > > > > So... would it be correct to say that with CONFIG_PREEMPT, ppp or its > > > underlying driver stack > > > > > > a) screws up the connection and hangs and > > > > > > b) scribbles on pagecache? > > > > > > Because if so, the same will probably happen on SMP. > > > > > Perhaps someone has the hardware to test this. > > > > To summarize my experience with the past 24 hours of testing: > > Without PREEMPT , everything is rock solid. > > so we've two separate problems: the first is the ppp instability with > preempt, the second is a regresion in the vm heuristics between 2.6.3 > and 2.6.5. Yes, that is correct. The instability was first noticed about one month ago when doing a bk pull from linus' repository. I've been updating my kernel via bk almost nightly, and around the time of 2.6.6-rc1 (IIRC), I got the Assertion `s && s->tree' failed message from bk. At first it was thought to be related to using an older version (3.0.1) of bk, so that was updated. A few days later, the problem recurred. Since it only happened about 15% to 20% of the time, and was easy to recover from, I didn't scream too loudly or too often to bitmover. But then, the problem started becoming more persistent about a week ago, so I began complaining again. I managed to get a bitkeeper-generated file to bitmover, who discovered that a very odd (or even in this case) number of NUL bytes existed where they should not exist. Hence this thread. Then during the course of testing, I noticed the significant difference in time it took to run a test script supplied by bitkeeper for current kernels versus an older vendor kernel. Hence your being cc'ed. > > > and I (cringes at the thought) may repeat some bk pulls with > > PREEMPT set. > > I've heard other reports of preempt being unstable with some sound > stuff, just in case are you using sound drivers at all during that > workload? > > Yes, mea culpa. CONFIG_SND_ENS1371=y. Steven