From mboxrd@z Thu Jan 1 00:00:00 1970 From: Valerie Aurora Subject: Re: Results of my VFS scaling evaluation. Date: Fri, 8 Oct 2010 20:38:42 -0400 Message-ID: <20101009003842.GH30846@shell> References: <1286580739.3153.57.camel@bobble.smo.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, mrubin@google.com To: Frank Mayhar Return-path: Received: from mx1.redhat.com ([209.132.183.28]:5951 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759925Ab0JIAis (ORCPT ); Fri, 8 Oct 2010 20:38:48 -0400 Content-Disposition: inline In-Reply-To: <1286580739.3153.57.camel@bobble.smo.corp.google.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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? -VAL