From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753537Ab0F3Lyb (ORCPT ); Wed, 30 Jun 2010 07:54:31 -0400 Received: from vpn.id2.novell.com ([195.33.99.129]:44970 "EHLO vpn.id2.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752080Ab0F3Lya convert rfc822-to-8bit (ORCPT ); Wed, 30 Jun 2010 07:54:30 -0400 Message-Id: <4C2B4CB10200007800008CDE@vpn.id2.novell.com> X-Mailer: Novell GroupWise Internet Agent 8.0.1 Date: Wed, 30 Jun 2010 12:54:57 +0100 From: "Jan Beulich" To: "Peter Zijlstra" Cc: "mingo@elte.hu" , "Jeremy Fitzhardinge" , "tglx@linutronix.de" , "Ky Srinivasan" , "linux-kernel@vger.kernel.org" , "hpa@zytor.com" Subject: Re: [PATCH 1/4, v2] x86: enlightenment for ticket spin locks - base implementation References: <4C2A1FE902000078000089E1@vpn.id2.novell.com> <1277885133.1868.71.camel@laptop> <4C2B23CD0200007800008BFA@vpn.id2.novell.com> <1277889116.1868.95.camel@laptop> <4C2B14BE.6080505@goop.org> <4C2B4A100200007800008CC5@vpn.id2.novell.com> <1277898525.1868.108.camel@laptop> In-Reply-To: <1277898525.1868.108.camel@laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> On 30.06.10 at 13:48, Peter Zijlstra wrote: > On Wed, 2010-06-30 at 12:43 +0100, Jan Beulich wrote: > >> It does tickle just the new owner - that's what the list is for. > > But if you have a FIFO list you don't need the ticket stuff and can > implement a FIFO lock instead. The list is LIFO (not FIFO, as only the most recently added entry is a candidate for needing wakeup as long as there's no interrupt re-enabling in irqsave lock paths), and is only used for tickling (not for deciding who's going to be the next owner). Jan