From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from hosted05.westnet.com.au ([203.10.1.219]) by bombadil.infradead.org with esmtp (Exim 4.68 #1 (Red Hat Linux)) id 1KXVfd-0003HX-7w for linux-mtd@lists.infradead.org; Mon, 25 Aug 2008 06:35:21 +0000 Message-ID: <48B2529B.8030906@snapgear.com> Date: Mon, 25 Aug 2008 16:35:07 +1000 From: Greg Ungerer MIME-Version: 1.0 To: Jared Hulbert Subject: Re: [PATCH 00/10] AXFS: Advanced XIP filesystem References: <48AD00C4.6060302@gmail.com> <20080821110749.GA1926@shareable.org> <6934efce0808210711t686a88eci6eb294dbb54d68fe@mail.gmail.com> <48AE0476.80109@snapgear.com> <6934efce0808211948kd12ba76k1ee847a0e08010e0@mail.gmail.com> In-Reply-To: <6934efce0808211948kd12ba76k1ee847a0e08010e0@mail.gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: cotte@de.ibm.com, linux-embedded@vger.kernel.org, nickpiggin@yahoo.com.au, =?UTF-8?B?SsO2cm4gRW5nZWw=?= , Jamie Lokier , Linux-kernel@vger.kernel.org, linux-mtd , tim.bird@am.sony.com List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Jared, Jared Hulbert wrote: >> That would be enough I think. If you could manually select >> which files are contiguous-and-uncompressed that would be >> useful for some too here. > > So.... If you don't have an MMU when do you call ->fault? Does the > noMMU code just loop through ->fault()ing all the pages in an mmap()? Sort of. It actually just uses a single ->read to bring in the entire file contents. There is a few limitations on the use of mmap() for non-mmu. Documentation/nommu-mmap.txt gives more details. With no MMU it does rely on being able to kmalloc() a single RAM region big enough to hold the entire file. >> One thing for sure is that many people who do non-MMU setups >> are interested in XIP to get the space savings. These are very >> often small devices with very constrained RAM and flash. (For >> whatever it is worth single NOR flash only boards are common in >> these smaller form factors :-) > > True. Regards Greg ------------------------------------------------------------------------ Greg Ungerer -- Chief Software Dude EMAIL: gerg@snapgear.com SnapGear -- a Secure Computing Company PHONE: +61 7 3435 2888 825 Stanley St, FAX: +61 7 3891 3630 Woolloongabba, QLD, 4102, Australia WEB: http://www.SnapGear.com