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

[Russell King]

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?

http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2006-November/036906.html

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   - http://www.arm.linux.org.uk/
 maintainer of:
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/