Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755196AbZALQFp (ORCPT ); Mon, 12 Jan 2009 11:05:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752677AbZALQFd (ORCPT ); Mon, 12 Jan 2009 11:05:33 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:39941 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752576AbZALQFc (ORCPT ); Mon, 12 Jan 2009 11:05:32 -0500 Date: Mon, 12 Jan 2009 08:04:22 -0800 (PST) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: Peter Zijlstra cc: Ingo Molnar , "Paul E. McKenney" , Gregory Haskins , Matthew Wilcox , Andi Kleen , Chris Mason , Andrew Morton , Linux Kernel Mailing List , linux-fsdevel , linux-btrfs , Thomas Gleixner , Nick Piggin , Peter Morreale , Sven Dietrich , Dmitry Adamushko Subject: Re: [PATCH -v8][RFC] mutex: implement adaptive spinning In-Reply-To: <1231774622.4371.96.camel@laptop> Message-ID: References: <1231774622.4371.96.camel@laptop> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) 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: 765 Lines: 24 On Mon, 12 Jan 2009, Peter Zijlstra wrote: > > Change mutex contention behaviour such that it will sometimes busy wait on > acquisition - moving its behaviour closer to that of spinlocks. This version seems worse in so many ways. You made the mutex bigger, for no obvious reason. You made it back into the locked version. You have unnecessary preempt_enable/preempt_disable calls in functions that need to be called (and are called) with preemption already disabled. Things seem to be going backwards. Linus -- 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/