Re: io resources and cached mappings (was: [git pull] drm patchesfor 2.6.27-rc1)

From: Ingo Molnar
Date: Thu Oct 23 2008 - 04:06:27 EST

* Keith Packard <keithp@xxxxxxxxxx> wrote:

> > okay. So ... mind sending your io_mapping patch as a generic
> > facility? It looks all good to me in its present form, except that
> > it should live in include/linux/io.h, not in the
> > drivers/gpu/drm/i915/io_reserve.h file
> > :-)
> The first patch in this series (assuming I'm driving git-send-email
> correctly) adds the io_mapping API. I ended up creating a new
> linux/io_mapping.h file as the kernel init code uses io.h and got very
> angry when I tried to include linux/highmem.h from that. I'm afraid I
> gave up at that point and just moved the code to a new file.

ah ... good call, i missed that mess. linux/io.h is indeed dependency
laden and it's best to keep new facilities separated anyway.

> The second patch switches the drm/i915 driver to the new API.
> Performance improvements on 64-bit kernels are impressive as we were
> using the slow path before and now get to take advantage of 64-bit
> wonderfulness.

heh, cool - the wonders of 64-bit x86 :-)

Any ballpark-figure numbers you can share with us?

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