From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from detroit.securenet-server.net ([209.51.153.26]:16618 "EHLO detroit.securenet-server.net") by vger.kernel.org with ESMTP id S1030211AbWCIA7W (ORCPT ); Wed, 8 Mar 2006 19:59:22 -0500 From: Jesse Barnes Subject: Re: [PATCH] Document Linux's memory barriers [try #2] Date: Wed, 8 Mar 2006 16:59:05 -0800 References: <20060308184500.GA17716@devserv.devel.redhat.com> <20060308194037.GO7301@parisc-linux.org> <17423.30924.278031.151438@cargo.ozlabs.ibm.com> In-Reply-To: <17423.30924.278031.151438@cargo.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200603081659.05786.jbarnes@virtuousgeek.org> Sender: linux-arch-owner@vger.kernel.org To: Paul Mackerras Cc: Matthew Wilcox , Linus Torvalds , David Howells , Alan Cox , akpm@osdl.org, mingo@redhat.com, linux-arch@vger.kernel.org, linuxppc64-dev@ozlabs.org, linux-kernel@vger.kernel.org List-ID: On Wednesday, March 8, 2006 4:37 pm, Paul Mackerras wrote: > Matthew Wilcox writes: > > Looking at the SGI implementation, it's smarter than you think. > > Looks like there's a register in the local I/O hub that lets you > > determine when this write has been queued in the appropriate > > host->pci bridge. > > Given that mmiowb takes no arguments, how does it know which is the > appropriate PCI host bridge? It uses a per-node address space to reference the local bridge. The local bridge then waits until the remote bridge has acked the write before, then sets the outstanding write register to the appropriate value. Jesse