From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751677AbXCULJu (ORCPT ); Wed, 21 Mar 2007 07:09:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751671AbXCULJu (ORCPT ); Wed, 21 Mar 2007 07:09:50 -0400 Received: from lazybastard.de ([212.112.238.170]:41475 "EHLO longford.lazybastard.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751366AbXCULJt (ORCPT ); Wed, 21 Mar 2007 07:09:49 -0400 Date: Wed, 21 Mar 2007 12:05:29 +0100 From: =?utf-8?B?SsO2cm4=?= Engel To: Thomas Gleixner Cc: Matt Mackall , Josh Boyer , Artem Bityutskiy , Linux Kernel Mailing List , Frank Haverkamp , Christoph Hellwig , David Woodhouse Subject: Re: [PATCH 00/22 take 3] UBI: Unsorted Block Images Message-ID: <20070321110528.GC3785@lazybastard.org> References: <20070318162720.GI10459@waste.org> <1174236579.17249.6.camel@sauron> <20070318191812.GM4892@waste.org> <20070318203149.GC29295@crusty.rchland.ibm.com> <20070319170838.GP4892@waste.org> <1174328188.30079.46.camel@zod.rchland.ibm.com> <20070319195442.GT4892@waste.org> <1174338329.13341.633.camel@localhost.localdomain> <20070319223205.GZ4892@waste.org> <1174351366.13341.739.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1174351366.13341.739.camel@localhost.localdomain> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 20 March 2007 01:42:46 +0100, Thomas Gleixner wrote: > On Mon, 2007-03-19 at 17:32 -0500, Matt Mackall wrote: > > > > > 4. JFFS2 has its own wear-leving scheme, as do several other > > > > filesystems, so they probably want to bypass this piece of the stack. > > > > > > JFFS2 on top of UBI delegates the wear levelling to UBI, as JFFS2s own > > > wear levelling sucks. > > > > Ok, fine. How about LogFS, then? > > LogFS can easily leverage UBI's wear algorithm. Ok, now we have reached the absurd. UBI quite fundamentally cannot do wear leveling as good as LogFS can. Simply because UBI has zero knowledge of the _contents_ of its blocks. Knowing whether a block is 90% garbage or not makes a great difference. Also LogFS currently requires erasesizes of 2^n. Thomas, I can give you my opinion on this flamewar in private - after you have cooled off. Jörn -- When I am working on a problem I never think about beauty. I think only how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong. -- R. Buckminster Fuller