From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759333Ab2EIRl0 (ORCPT ); Wed, 9 May 2012 13:41:26 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:60767 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755789Ab2EIRlU (ORCPT ); Wed, 9 May 2012 13:41:20 -0400 Date: Wed, 9 May 2012 10:41:14 -0700 From: Tejun Heo To: Alan Stern Cc: "Eric W. Biederman" , Peter Zijlstra , Kernel development list Subject: Re: Lockdep false positive in sysfs Message-ID: <20120509174114.GE24636@google.com> References: <20120507215518.GN19417@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Tue, May 08, 2012 at 02:53:11PM -0400, Alan Stern wrote: > On Mon, 7 May 2012, Tejun Heo wrote: > > > On Mon, May 07, 2012 at 05:51:52PM -0400, Alan Stern wrote: > > > I guess in the end it's a question of balance. Which has more > > > overhead, adding a few function calls here and there, or adding a new > > > flags field to every struct attribute? > > > > Yes, and there are different types of overheads. I'm happy to trade > > some runtime memory overhead under debugging mode for lower code > > complexity. Lock proving is pretty expensive anyway. I don't think > > there's much point in trying to optimize some bytes from struct > > attributes. > > Okay, then what do you think about this approach? It does seem smaller > and simpler than the previous attempt. > > And I did try to avoid unnecessary bloat; if lockdep isn't being used > then the extra attribute flag isn't present. Yeap, looks good to me. Thanks. -- tejun