From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 8 Nov 2002 14:21:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 8 Nov 2002 14:21:44 -0500 Received: from deimos.hpl.hp.com ([192.6.19.190]:29691 "EHLO deimos.hpl.hp.com") by vger.kernel.org with ESMTP id ; Fri, 8 Nov 2002 14:21:41 -0500 From: David Mosberger MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15820.4071.102881.673519@napali.hpl.hp.com> Date: Fri, 8 Nov 2002 11:26:31 -0800 To: Matthew Wilcox Cc: "Van Maren, Kevin" , "''Linus Torvalds ' '" , "''Jeremy Fitzhardinge ' '" , "''William Lee Irwin III ' '" , "''linux-ia64@linuxia64.org ' '" , "''Linux Kernel List ' '" , "''rusty@rustcorp.com.au ' '" , "''dhowells@redhat.com ' '" , "''mingo@elte.hu ' '" Subject: Re: [Linux-ia64] reader-writer livelock problem In-Reply-To: <20021108191907.N12011@parcelfarce.linux.theplanet.co.uk> References: <3FAD1088D4556046AEC48D80B47B478C0101F4EE@usslc-exch-4.slc.unisys.com> <20021108191907.N12011@parcelfarce.linux.theplanet.co.uk> X-Mailer: VM 7.07 under Emacs 21.2.1 Reply-To: davidm@hpl.hp.com X-URL: http://www.hpl.hp.com/personal/David_Mosberger/ Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org >>>>> On Fri, 8 Nov 2002 19:19:07 +0000, Matthew Wilcox said: Matthew> On Fri, Nov 08, 2002 at 12:05:30PM -0600, Van Maren, Kevin Matthew> wrote: >> Absolutely you should minimize the locking contention. However, >> that isn't always possible, such as when you have 64 processors >> contending on the same resource. Matthew> if you've got 64 processors contending on the same Matthew> resource, maybe you need to split that resource up so they Matthew> can have a copy each. all that cacheline bouncing can't do Matthew> your numa boxes any good. Matthew, please understand that this is NOT a performance problem. It's a correctness problem. If livelock can resolut from read-write locks, it's a huge security problem. Period. --david