Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757280AbZAHDig (ORCPT ); Wed, 7 Jan 2009 22:38:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751749AbZAHDiX (ORCPT ); Wed, 7 Jan 2009 22:38:23 -0500 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123]:47283 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751189AbZAHDiV (ORCPT ); Wed, 7 Jan 2009 22:38:21 -0500 Date: Wed, 7 Jan 2009 22:38:18 -0500 (EST) From: Steven Rostedt X-X-Sender: rostedt@gandalf.stny.rr.com To: Gregory Haskins cc: Linus Torvalds , Andi Kleen , Matthew Wilcox , Peter Zijlstra , paulmck@linux.vnet.ibm.com, Ingo Molnar , Chris Mason , Andrew Morton , Linux Kernel Mailing List , linux-fsdevel , linux-btrfs , Thomas Gleixner , Nick Piggin , Peter Morreale , Sven Dietrich Subject: Re: [PATCH -v5][RFC]: mutex: implement adaptive spinning In-Reply-To: <49657297.9000708@novell.com> Message-ID: References: <1231281801.11687.125.camel@twins> <1231283778.11687.136.camel@twins> <1231329783.11687.287.camel@twins> <1231347442.11687.344.camel@twins> <20090107210923.GV2002@parisc-linux.org> <20090107213924.GP496@one.firstfloor.org> <49652C7C.3000909@novell.com> <49657297.9000708@novell.com> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) 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 Content-Length: 1033 Lines: 24 On Wed, 7 Jan 2009, Gregory Haskins wrote: > > In my defense, the -rt versions of the patches guarantee this is ok > based on a little hack: The -rt versions worry about much more than what the mutex code in mainline does. Linus is correct in his arguments. The adaptive mutex (as suppose to what -rt has), is only to help aid in preformance. There are a lot of races that can happen in mainline version where lock taking may not be fifo, or where we might start to schedule when we could have taken the lock. These races are not in -rt, but that is because -rt cares about these. But mainline cares more about performance over determinism. This means that we have to look at the current code that Peter is submitting with a different perspective than we do in -rt. -- Steve -- 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/