From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760485AbYETCex (ORCPT ); Mon, 19 May 2008 22:34:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756129AbYETCep (ORCPT ); Mon, 19 May 2008 22:34:45 -0400 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:48866 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1755057AbYETCeo (ORCPT ); Mon, 19 May 2008 22:34:44 -0400 Date: Mon, 19 May 2008 19:34:39 -0700 (PDT) Message-Id: <20080519.193439.31663045.davem@davemloft.net> To: benh@kernel.crashing.org Cc: geoffrey.levand@am.sony.com, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, paulus@samba.org Subject: Re: [patch v2] LMB: Add basic spin locking to lmb From: David Miller In-Reply-To: <1211250778.8297.159.camel@pasglop> References: <48322191.6060909@am.sony.com> <20080519.192215.193701293.davem@davemloft.net> <1211250778.8297.159.camel@pasglop> X-Mailer: Mew version 5.2 on Emacs 22.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Benjamin Herrenschmidt Date: Mon, 19 May 2008 22:32:58 -0400 > I think the core memory hotplug is... However, we used to not change the > LMB when doing so (afaik, I'm travelling and not looking at the code > right now). However, things like PS3 memory hotplug tries to keep LMB is > sync for the sake of /dev/mem or similar and that happens before the > memory is added to the core. But if the memory hotplug is synchronized, so are changes to the LMB tables. And if there are LMB read side access concernes outside of the hotplug event, ideally we should use the synchronization mechanism that hotplug uses instead of adding a new one.