From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268165AbUHKSCZ (ORCPT ); Wed, 11 Aug 2004 14:02:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268145AbUHKSAG (ORCPT ); Wed, 11 Aug 2004 14:00:06 -0400 Received: from mailer.nec-labs.com ([138.15.108.3]:49359 "EHLO mailer.nec-labs.com") by vger.kernel.org with ESMTP id S268156AbUHKR6r (ORCPT ); Wed, 11 Aug 2004 13:58:47 -0400 Message-ID: <411A5E55.3050508@nec-labs.com> Date: Wed, 11 Aug 2004 10:58:45 -0700 From: Lei Yang User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040114 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Phillip Lougher CC: linux-kernel@vger.kernel.org Subject: Re: Compression algorithm in cloop References: <411A4D34.6000104@lougher.demon.co.uk> In-Reply-To: <411A4D34.6000104@lougher.demon.co.uk> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 11 Aug 2004 17:58:42.0258 (UTC) FILETIME=[D6891320:01C47FCC] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org If I don't want to build a new compression library and port it to kernel, all I want to do is to try out the idea -- whether it could work on cloop, whether the compression ratio is acceptable, can I just change the cloop code? In other words, I just need a loopback block device with other compression scheme. I know that adding the new algorithm support to kernel would be standard way to do this and would be helpful to more people, it's just that I don't have that time :( Phillip Lougher wrote: > > Hello, > > > > I am trying to do some experiment on compression ratios with cloop. I > > know that currently cloop uses zlib. How can I change it to other > > algorithms? > > Changing the algorithm from gzip is going to be probably unpopular. > Cloop uses the gzip deflate library inside the kernel shared by a > large number of other programs. To change the algorithm you'll have > to add more (private) decompression code to the kernel. This is a > retrograde > step because the shared library was only introduced in 2.4.17 to avoid lots > of private copies of gzip. > > > Where should I start from? Really a newbie to this, > > appreciate any comments and suggestions!! > > There has been discussion on this list before about adding > bzip2 support to the kernel. Do a search on the list for this. > > Regards > > Phillip >