Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936938AbXFGVPu (ORCPT ); Thu, 7 Jun 2007 17:15:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S936951AbXFGVP3 (ORCPT ); Thu, 7 Jun 2007 17:15:29 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:45446 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935743AbXFGVP1 (ORCPT ); Thu, 7 Jun 2007 17:15:27 -0400 Date: Thu, 7 Jun 2007 22:15:19 +0100 From: Christoph Hellwig To: Jared Hulbert Cc: Christoph Hellwig , carsteno@de.ibm.com, Nick Piggin , Andrew Morton , richard.griffiths@windriver.com, Richard Griffiths , Linux-kernel@vger.kernel.org Subject: Re: [PATCH 2.6.21] cramfs: add cramfs Linear XIP Message-ID: <20070607211519.GA22348@infradead.org> Mail-Followup-To: Christoph Hellwig , Jared Hulbert , carsteno@de.ibm.com, Nick Piggin , Andrew Morton , richard.griffiths@windriver.com, Richard Griffiths , Linux-kernel@vger.kernel.org References: <6934efce0706011748p46cf7995vdca0b9cc3f0b06a3@mail.gmail.com> <46612D6F.6000002@yahoo.com.au> <46641472.3080802@de.ibm.com> <6934efce0706060413y6e74512s19d5f468106d4b85@mail.gmail.com> <20070606113351.GA11701@infradead.org> <6934efce0706060907n209fe6bcnb470101196aa9c55@mail.gmail.com> <20070606161621.GA20247@infradead.org> <6934efce0706061126n551cccaeg68a0def87457911@mail.gmail.com> <20070607193707.GA17144@infradead.org> <6934efce0706071411y6d184629i5ce0694175bef164@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6934efce0706071411y6d184629i5ce0694175bef164@mail.gmail.com> User-Agent: Mutt/1.4.2.2i X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1692 Lines: 36 On Thu, Jun 07, 2007 at 02:11:44PM -0700, Jared Hulbert wrote: > >that even more important doesn't require pulling in > >the whole block layer which is especially important for embedded > >devices at the lower end of the scala. > > Good point. That is a big oversight. Though I would prefer to handle > that in the same fs rather than fork. If if were actually talking about complex filesystem I'd agree. But the cramfs xip patch posted here touches about 2/3 of the number of lines that cramfs has in total. And cramfs is not exactly the best base to start with.. > >I still think it'd be even better to just > >hook xip support into jffs or logfs because they give you a full > >featured flash filesystem for all needs without the complexity > >of strictly partitioning between xip-capable and write parts > >of your storage. > > This is nirvana. But it is not the goal of the patches in question. > In fact there are several use cases that don't need and don't value > the writeability and don't need therefore the overhead. It is a long > term goal never the less. With the filemap_xip.c helpers adding xip support to any filesystem is pretty trivial for the highlevel filesystem operations. The only interesting bit is the lowlevel code (the get_xip_page method and the others Carsten mentioned), but we need to do these lowlevel code in a generic and proper way anyway. I'll try to hack up an xip prototype for jffs2 next week. - 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/