From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id 7FF156B0071 for ; Mon, 11 Oct 2010 14:47:37 -0400 (EDT) Received: from wpaz1.hot.corp.google.com (wpaz1.hot.corp.google.com [172.24.198.65]) by smtp-out.google.com with ESMTP id o9BIlZ2C015887 for ; Mon, 11 Oct 2010 11:47:36 -0700 Received: from vws1 (vws1.prod.google.com [10.241.21.129]) by wpaz1.hot.corp.google.com with ESMTP id o9BIlYZ9004099 for ; Mon, 11 Oct 2010 11:47:34 -0700 Received: by vws1 with SMTP id 1so1895299vws.27 for ; Mon, 11 Oct 2010 11:47:34 -0700 (PDT) Subject: Re: Results of my VFS scaling evaluation. From: Frank Mayhar In-Reply-To: <20101009003842.GH30846@shell> References: <1286580739.3153.57.camel@bobble.smo.corp.google.com> <20101009003842.GH30846@shell> Content-Type: text/plain; charset="UTF-8" Date: Mon, 11 Oct 2010 11:47:28 -0700 Message-ID: <1286822848.29899.305.camel@bobble.smo.corp.google.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Valerie Aurora Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, mrubin@google.com List-ID: On Fri, 2010-10-08 at 20:38 -0400, Valerie Aurora wrote: > On Fri, Oct 08, 2010 at 04:32:19PM -0700, Frank Mayhar wrote: > > > > Before going into details of the test results, however, I must say that > > the most striking thing about Nick's work how stable it is. In all of > > :D > > > the work I've been doing, all the kernels I've built and run and all the > > tests I've run, I've run into no hangs and only one crash, that in an > > area that we happen to stress very heavily, for which I posted a patch, > > available at > > http://www.kerneltrap.org/mailarchive/linux-fsdevel/2010/9/27/6886943 > > The crash involved the fact that we use cgroups very heavily, and there > > was an oversight in the new d_set_d_op() routine that failed to clear > > flags before it set them. > > I honestly can't stand the d_set_d_op() patch (testing flags instead > of d_op->op) because it obfuscates the code in such a way that leads > directly to this kind of bug. I don't suppose you could test the > performance effect of that specific patch and see how big of a > difference it makes? I do kind of understand why he did it but you're right that it makes things a bit error-prone. Unfortunately I'm not in a position at the moment to do a lot more testing and analysis. I'll try to find some spare time in which to do some more testing of both this and Dave Chinner's tree, but no promises. -- Frank Mayhar Google Inc. -- 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