Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756782AbZAJX70 (ORCPT ); Sat, 10 Jan 2009 18:59:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753916AbZAJX7Q (ORCPT ); Sat, 10 Jan 2009 18:59:16 -0500 Received: from gw.goop.org ([64.81.55.164]:47685 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752176AbZAJX7O (ORCPT ); Sat, 10 Jan 2009 18:59:14 -0500 Message-ID: <49693649.1020406@goop.org> Date: Sun, 11 Jan 2009 10:59:05 +1100 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.19 (X11/20090105) MIME-Version: 1.0 To: Linus Torvalds CC: Chris Mason , Steven Rostedt , Peter Zijlstra , Ingo Molnar , paulmck@linux.vnet.ibm.com, Gregory Haskins , Matthew Wilcox , Andi Kleen , Andrew Morton , Linux Kernel Mailing List , linux-fsdevel , linux-btrfs , Thomas Gleixner , Nick Piggin , Peter Morreale , Sven Dietrich Subject: Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning References: <1231441350.14304.48.camel@think.oraclecorp.com> In-Reply-To: X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 752 Lines: 19 Linus Torvalds wrote: > Actually, the real spin locks are now fair. We use ticket locks on x86. > > Well, at least we do unless you enable that broken paravirt support. I'm > not at all clear on why CONFIG_PARAVIRT wants to use inferior locks, but I > don't much care. > No, it will continue to use ticket locks, but there's the option to switch to byte locks or something else. Ticket locks are awesomely bad when the VCPU scheduler fights with the run-order required by the ticket order. J -- 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/