From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH 10/10] mm: per device dirty threshold From: Peter Zijlstra In-Reply-To: <1177156902.2934.96.camel@lappy> References: <20070420155154.898600123@chello.nl> <20070420155503.608300342@chello.nl> <20070421025532.916b1e2e.akpm@linux-foundation.org> <1177156902.2934.96.camel@lappy> Content-Type: text/plain Date: Sat, 21 Apr 2007 14:15:08 +0200 Message-Id: <1177157708.2934.100.camel@lappy> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, miklos@szeredi.hu, neilb@suse.de, dgc@sgi.com, tomoki.sekiyama.qu@hitachi.com, nikita@clusterfs.com, trond.myklebust@fys.uio.no, yingchao.zhou@gmail.com List-ID: > > > +/* > > > + * maximal error of a stat counter. > > > + */ > > > +static inline unsigned long bdi_stat_delta(void) > > > +{ > > > +#ifdef CONFIG_SMP > > > + return NR_CPUS * FBC_BATCH; > > > > This is enormously wrong for CONFIG_NR_CPUS=1024 on a 2-way. Right, I knew about that but, uhm. I wanted to make that num_online_cpus(), and install a hotplug notifier to fold the percpu delta back into the total on cpu offline. But I have to look into doing that hotplug notifier stuff. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org