Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261492AbVCaO7F (ORCPT ); Thu, 31 Mar 2005 09:59:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261490AbVCaO7F (ORCPT ); Thu, 31 Mar 2005 09:59:05 -0500 Received: from mx1.elte.hu ([157.181.1.137]:43987 "EHLO mx1.elte.hu") by vger.kernel.org with ESMTP id S261488AbVCaO6m (ORCPT ); Thu, 31 Mar 2005 09:58:42 -0500 Date: Thu, 31 Mar 2005 16:58:25 +0200 From: Ingo Molnar To: Trond Myklebust Cc: Andrew Morton , rlrevell@joe-job.com, linux-kernel@vger.kernel.org Subject: Re: NFS client latencies Message-ID: <20050331145825.GA5107@elte.hu> References: <1112240918.10975.4.camel@lade.trondhjem.org> <20050331065942.GA14952@elte.hu> <20050330231801.129b0715.akpm@osdl.org> <20050331073017.GA16577@elte.hu> <1112270304.10975.41.camel@lade.trondhjem.org> <1112272451.10975.72.camel@lade.trondhjem.org> <20050331135825.GA2214@elte.hu> <1112279522.20211.8.camel@lade.trondhjem.org> <20050331143930.GA4032@elte.hu> <1112280891.20211.29.camel@lade.trondhjem.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1112280891.20211.29.camel@lade.trondhjem.org> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamVersion: MailScanner 4.31.6-itk1 (ELTE 1.2) SpamAssassin 2.63 ClamAV 0.73 X-ELTE-VirusStatus: clean X-ELTE-SpamCheck: no X-ELTE-SpamCheck-Details: score=-4.9, required 5.9, autolearn=not spam, BAYES_00 -4.90 X-ELTE-SpamLevel: X-ELTE-SpamScore: -4 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1266 Lines: 29 * Trond Myklebust wrote: > Errm... That looks a bit unsafe. What is there then to stop another > process from removing "pos" while you are scheduling? It seems to me > that you should really start afresh in that case. yeah. > The good news, though, is that because requests on the "commit" list > do not remain locked for long without being removed from the list, you > should rarely have to skip them. IOW restarting from the head of the > list is pretty much the same as starting from where you left off. as we've learned it through painful experience on the ext3 side, restarting scans where 'skipping' has to be done is unhealthy. would it be safe to collect locked entries into a separate, local list, so that the restart would only see newly added entries? Then once the moving of all entries has been done, all the locked entries could be added back to the commit_list via one list_add. (can anything happen to those locked entries that would break this method?) Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/