Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751998AbXBDDYI (ORCPT ); Sat, 3 Feb 2007 22:24:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752011AbXBDDYI (ORCPT ); Sat, 3 Feb 2007 22:24:08 -0500 Received: from firewall.rowland.harvard.edu ([140.247.233.35]:64492 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with SMTP id S1751998AbXBDDYH (ORCPT ); Sat, 3 Feb 2007 22:24:07 -0500 Date: Sat, 3 Feb 2007 22:24:04 -0500 (EST) From: Alan Stern X-X-Sender: stern@netrider.rowland.org To: "Paul E. McKenney" cc: Oleg Nesterov , Peter Zijlstra , Ingo Molnar , Christoph Hellwig , Andrew Morton , Subject: Re: [PATCH 3/7] barrier: a scalable synchonisation barrier In-Reply-To: <20070204002338.GB5647@linux.vnet.ibm.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1055 Lines: 24 On Sat, 3 Feb 2007, Paul E. McKenney wrote: > > And another note: this all assumes that STORE-MB-LOAD works "correctly", yes? > > We have other code which relies on that, should not be a problem. > > We have been working with Doug Lea of SUNY Oswego, Sebatian Burckhardt of > University of Pennsylvania, and Vijay Saraswat of IBM Research towards > a "universal memory model" that accommodates all machines. Currently, > it does in fact handle store-mb-load the way we all want, thankfully! We should add that many places in the kernel do depend on proper behavior for this data access pattern. So whatever "universal memory model" we end up with, it had better handle the pattern correctly if Linux is to support it. It's interesting to note, however, that this does exclude simple MESI. Alan Stern - 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/