Re: [PATCH 2/2] cuse: implement memory mapping

From: Linus Torvalds
Date: Fri Jan 13 2012 - 13:20:19 EST


On Fri, Jan 13, 2012 at 9:06 AM, Miklos Szeredi <miklos@xxxxxxxxxx> wrote:
> From: Tejun Heo <htejun@xxxxxxxxx>
>
> This implements memory mapping of char devices.

I don't think this is how you want to do it.

It seems to maintain a page list of its own, and do the magic page
fault etc behavior. Which to me smells like a really bad design.

I would expect that what you actually want to do is to expose it as a
shared mmap, and depend on all the normal shmem support. Is there any
reason not to do that?

I guess you don't generally have big mappings, so an argument like
"that way you can page out pages etc" may not strike you as a very
strong argument, but I'd still prefer to at least see that approach
explored. Hmm?

Linus
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