Messages in this thread | | | Date | Mon, 25 Aug 2008 16:35:07 +1000 | From | Greg Ungerer <> | Subject | Re: [PATCH 00/10] AXFS: Advanced XIP filesystem |
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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
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