Re: fuse, get_user_pages, flush_anon_page, aliasing caches and all that again

From: Russell King
Date: Sun Dec 31 2006 - 04:56:05 EST

On Sun, Dec 31, 2006 at 10:27:22AM +0100, Arjan van de Ven wrote:
> >
> > However, it's not only FUSE which is suffering - direct-IO also doesn't
> > work.
> for direct-IO the kernel won't touch the data *at all*... (that's the
> point ;)

Wrong. One word: PIO. We _still_ to this day have no guarantee by
block device drivers that the data they've read into the page cache
will be flushed into RAM rather than sitting in the CPU cache.

> is it still an issue then?

Depends if you think about that patch I guess. If you're an embedded
person trying to get direct-IO working on ARM I guess that patch is
very attractive, even if it is distasteful to us.

Russell King
Linux kernel 2.6 ARM Linux -
maintainer of:
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