Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161694AbWKEUQt (ORCPT ); Sun, 5 Nov 2006 15:16:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161697AbWKEUQt (ORCPT ); Sun, 5 Nov 2006 15:16:49 -0500 Received: from terminus.zytor.com ([192.83.249.54]:51420 "EHLO terminus.zytor.com") by vger.kernel.org with ESMTP id S1161694AbWKEUQs (ORCPT ); Sun, 5 Nov 2006 15:16:48 -0500 Message-ID: <454E46A8.20106@zytor.com> Date: Sun, 05 Nov 2006 12:16:40 -0800 From: "H. Peter Anvin" User-Agent: Thunderbird 1.5.0.7 (X11/20061008) MIME-Version: 1.0 To: Maurizio Lombardi CC: linux-kernel@vger.kernel.org Subject: Re: New filesystem for Linux References: <454A76CC.6030003@cosmosbay.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 878 Lines: 25 Maurizio Lombardi wrote: > On 11/4/06, Mikulas Patocka wrote: > >> free space is organized in lists of free runs >> and converted to bitmap only in case of >> extreme fragmentation. > > There is a performance reason to prefer lists of free blocks rather than > bitmap? > > I read from [Tanenbaum: Operating System, Design and Implementation II > ed. ] that lists are better than bitmap only when disk is almost full. > Yes, if you have a truly random access medium. If you have media like physical disks, where fragmentation costs you, the lists will kill you dead in no time at all. -hpa - 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/