From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx148.postini.com [74.125.245.148]) by kanga.kvack.org (Postfix) with SMTP id B98636B0069 for ; Fri, 17 Aug 2012 19:33:25 -0400 (EDT) Received: from /spool/local by e33.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 17 Aug 2012 17:33:24 -0600 Received: from d03relay01.boulder.ibm.com (d03relay01.boulder.ibm.com [9.17.195.226]) by d03dlp03.boulder.ibm.com (Postfix) with ESMTP id A9A5119D803D for ; Fri, 17 Aug 2012 17:33:22 -0600 (MDT) Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d03relay01.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q7HNXMa4178510 for ; Fri, 17 Aug 2012 17:33:22 -0600 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q7HNXL7p026547 for ; Fri, 17 Aug 2012 17:33:22 -0600 Message-ID: <502ED4C0.70305@linux.vnet.ibm.com> Date: Fri, 17 Aug 2012 18:33:20 -0500 From: Seth Jennings MIME-Version: 1.0 Subject: Re: [PATCH 0/4] promote zcache from staging References: <1343413117-1989-1-git-send-email-sjenning@linux.vnet.ibm.com> <5021795A.5000509@linux.vnet.ibm.com> <5024067F.3010602@linux.vnet.ibm.com> <2e9ccb4f-1339-4c26-88dd-ea294b022127@default> <50254F69.2000409@linux.vnet.ibm.com> <8fa37327-17ff-4734-9007-40412b18d0fb@default> In-Reply-To: <8fa37327-17ff-4734-9007-40412b18d0fb@default> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Dan Magenheimer Cc: Greg Kroah-Hartman , Andrew Morton , Nitin Gupta , Minchan Kim , Konrad Wilk , Robert Jennings , linux-mm@kvack.org, linux-kernel@vger.kernel.org, devel@driverdev.osuosl.org, Kurt Hackel On 08/17/2012 05:21 PM, Dan Magenheimer wrote: >> From: Seth Jennings [mailto:sjenning@linux.vnet.ibm.com] >> Subject: Re: [PATCH 0/4] promote zcache from staging >> >> On 08/09/2012 03:20 PM, Dan Magenheimer wrote >>> I also wonder if you have anything else unusual in your >>> test setup, such as a fast swap disk (mine is a partition >>> on the same rotating disk as source and target of the kernel build, >>> the default install for a RHEL6 system)? >> >> I'm using a normal SATA HDD with two partitions, one for >> swap and the other an ext3 filesystem with the kernel source. >> >>> Or have you disabled cleancache? >> >> Yes, I _did_ disable cleancache. I could see where having >> cleancache enabled could explain the difference in results. > > Sorry to beat a dead horse, but I meant to report this > earlier in the week and got tied up by other things. > > I finally got my test scaffold set up earlier this week > to try to reproduce my "bad" numbers with the RHEL6-ish > config file. > > I found that with "make -j28" and "make -j32" I experienced > __DATA CORRUPTION__. This was repeatable. I actually hit this for the first time a few hours ago when I was running performance for your rewrite. I didn't know what to make of it yet. The 24-thread kernel build failed when both frontswap and cleancache were enabled. > The type of error led me to believe that the problem was > due to concurrency of cleancache reclaim. I did not try > with cleancache disabled to prove/support this theory > but it is consistent with the fact that you (Seth) have not > seen a similar problem and has disabled cleancache. > > While this problem is most likely in my code and I am > suitably chagrined, it re-emphasizes the fact that > the current zcache in staging is 20-month old "demo" > code. The proposed new zcache codebase handles concurrency > much more effectively. I imagine this can be solved without rewriting the entire codebase. If your new code contains a fix for this, can we just pull it as a single patch? Seth -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org