From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760638Ab2EIRrg (ORCPT ); Wed, 9 May 2012 13:47:36 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:35053 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754924Ab2EIRrf (ORCPT ); Wed, 9 May 2012 13:47:35 -0400 Date: Wed, 9 May 2012 13:47:34 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Tejun Heo cc: "Eric W. Biederman" , Peter Zijlstra , Kernel development list Subject: Re: Lockdep false positive in sysfs In-Reply-To: <20120509174114.GE24636@google.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 9 May 2012, Tejun Heo wrote: > 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. Unless there are any objections from Eric or Peter in the next few days, I'll submit it. Can I add your Acked-by? Alan Stern