Re: Fwd: Re: flush_cache_page()

[Russell King <rmk+lkml@arm.linux.org.uk>]

On Tue, Jan 11, 2005 at 04:07:09PM -0800, Linus Torvalds wrote:
> On Tue, 11 Jan 2005, Russell King wrote:
> > Any responses on this?  Didn't get any last time I mailed this out.
> 
> I don't have any real objections. I'd like it verified that gcc can
> compile away all the overhead on the architectures that don't use the pfn, 
> since "page_to_pfn()" can be a bit expensive otherwise.. But I don't see 
> anything wrong with the approach.

Thanks for the response.  However, apart from Ralph, Paul and yourself,
it seems none of the other architecture maintainers care about this
patch - the original mail was BCC'd to the architecture list.  Maybe
that's an implicit acceptance of this patch, I don't know.

I do know that page_to_pfn() will generate code on some platforms which
don't require it due to them declaring flush_cache_page() as a function.
However, I assert that if they don't need this overhead, that's for them
to fix up.  I don't know all their quirks so it isn't something I can
tackle.

In other words, unless I actually receive some real help from the other
architecture maintainers on this to address your concerns, ARM version 6
CPUs with aliasing L1 caches (== >16K) will remain a dead dodo with
mainline Linux kernels.

(This mail BCC'd to the architecture list again in the vain hope that
someone will offer assistance.)

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                 2.6 Serial core