From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759539AbYETCWa (ORCPT ); Mon, 19 May 2008 22:22:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753246AbYETCWV (ORCPT ); Mon, 19 May 2008 22:22:21 -0400 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:36605 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752151AbYETCWU (ORCPT ); Mon, 19 May 2008 22:22:20 -0400 Date: Mon, 19 May 2008 19:22:15 -0700 (PDT) Message-Id: <20080519.192215.193701293.davem@davemloft.net> To: geoffrey.levand@am.sony.com Cc: linux-kernel@vger.kernel.org, benh@kernel.crashing.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: <48322191.6060909@am.sony.com> References: <20080515.000203.225783838.davem@davemloft.net> <48321DF9.6060807@am.sony.com> <48322191.6060909@am.sony.com> 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: Geoff Levand Date: Mon, 19 May 2008 17:55:45 -0700 > Add a spinlock to struct lmb to enforce concurrency in > lmb_add(), lmb_remove(), lmb_analyze(), lmb_find(), and > lmb_dump_all(). > > This locking is needed for SMP systems that access the lmb structure > during hot memory add and remove operations after secondary cpus > have been started. > > Signed-off-by: Geoff Levand > --- > > v2: o Add locking to lmb_find(). I'm not against this patch, but I'm pretty sure it's not necessary. Isn't memory hotplug already synchronized at a higher level? If not, it should be.