Re: AZFS file system proposal

From: Maxim Shchetynin
Date: Tue Jun 17 2008 - 05:07:20 EST


> >+config AZ_FS
> >+ tristate "AZFS filesystem support"
>
> This is slightly redundant, it should probably be
> tristate "AZ filesystem support"

I have called it the same way as other file systems (in Kconfig they say "JFS filesystem support", "XFS filesystem support", "NTFS file system support", ...)

> >+ help
> >+ azfs is a file system for I/O attached memory backing. It requires
> >+ a block device with direct_access capability, e.g. axonram.
>
> (a) What is axonram?
> (b) why is axonram direct_access, and my other devices (including
> standard PC RAM) not?

Axonram is a module specific for IBM CellBlade and allows access to a DDR2 memory attached onto Axon controller.
You don't need direct_access and not azfs for main memory because there is already a pretty nice tmpfs for it.

> >+ Mounting such device with azfs gives memory mapped access to the
> >+ underlying memory to user space.
>
> Can't I just mmap(/dev/theblockdevice), why would I need to go through
> azfs?

Yes, you can mmap it. But what does it have to do with a file system. I would say you can either mmap it or place a file system on it.

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Mit freundlichen GrÃÃen / met vriendelijke groeten / avec regards

Maxim V. Shchetynin
Linux Kernel Entwicklung
IBM Deutschland Entwicklung GmbH
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