Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755480AbXKRW06 (ORCPT ); Sun, 18 Nov 2007 17:26:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752570AbXKRW0u (ORCPT ); Sun, 18 Nov 2007 17:26:50 -0500 Received: from relay1.sgi.com ([192.48.171.29]:33132 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752527AbXKRW0t (ORCPT ); Sun, 18 Nov 2007 17:26:49 -0500 Date: Mon, 19 Nov 2007 09:26:20 +1100 From: David Chinner To: Peter Zijlstra Cc: Daniel Walker , Ingo Molnar , Remy Bohmer , Steven Rostedt , Thomas Gleixner , RT , linux-kernel , Dave Chinner Subject: Re: [BUG on PREEMPT_RT, 2.6.23.1-rt5] in rt-mutex code and signals Message-ID: <20071118222620.GN66820511@sgi.com> References: <3efb10970711170344n670d8b69w6679d494922c5bb@mail.gmail.com> <1195316550.25393.21.camel@imap.mvista.com> <3efb10970711170909n3acca605j70525e36faf8da7f@mail.gmail.com> <1195320569.25393.38.camel@imap.mvista.com> <20071117174608.GA30641@elte.hu> <1195322141.25393.41.camel@imap.mvista.com> <20071117180430.GA10768@elte.hu> <1195323177.25393.56.camel@imap.mvista.com> <1195389230.6747.5.camel@twins> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1195389230.6747.5.camel@twins> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1018 Lines: 31 On Sun, Nov 18, 2007 at 01:33:50PM +0100, Peter Zijlstra wrote: > > On Sat, 2007-11-17 at 10:12 -0800, Daniel Walker wrote: > > > What specifically is wrong with dev->sem ? > > Nothing really, other than that they use semaphores to avoid lockdep :-/ > > I think I know how to annotate this, after Alan Stern explained all the > use cases, but I haven't come around to implementing it. Hope to do that > soonish. > > Another real semaphore user is XFS, they really use the down/up > asymmetry that semaphores allow, last time I spoke with Dave Chinner he > didn't know a way around this. Hasn't changed recently. We could convert some to completions, but others are much more difficult. Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/