From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762984AbXIXTLT (ORCPT ); Mon, 24 Sep 2007 15:11:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759138AbXIXTLF (ORCPT ); Mon, 24 Sep 2007 15:11:05 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:45658 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756235AbXIXTLD (ORCPT ); Mon, 24 Sep 2007 15:11:03 -0400 Date: Mon, 24 Sep 2007 12:10:35 -0700 From: Andrew Morton To: Christoph Hellwig Cc: Dave Hansen , linux-kernel@vger.kernel.org Subject: Re: [PATCH 24/25] r/o bind mounts: track number of mount writers Message-Id: <20070924121035.8d8c6ce2.akpm@linux-foundation.org> In-Reply-To: <20070924175411.GA2314@infradead.org> References: <20070920195249.852667D5@kernel> <20070920195320.38C8E20D@kernel> <20070924175411.GA2314@infradead.org> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.6; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 24 Sep 2007 18:54:11 +0100 Christoph Hellwig wrote: > As we already say in various messages the percpu counters in here > look rather fishy. I'd recomment to take a look at the per-cpu > superblock counters in XFS as they've been debugged quite well > now and could probably be lifted into a generic library for this > kind of think. The code is mostly in fs/xfs/xfs_mount.c can > can be spotted by beeing under #ifdef HAVE_PERCPU_SB. > > It also handles cases like hotplug cpu nicely that this code > seems to work around by always iterating over all possible cpus > which might not be nice on a dual core laptop with a distro kernel > that also has to support big iron. hm. How come xfs invented a new version of percpu_counters?