No "eventually" here, it does the mapping now. Also s/Fech/Fetch/. Also, I would say "_PXM" method instead of label because that is the nomenclature used in the ACPI specs. I would also possibly shorten the description a bit: "If a device has a _PXM method, map that to a NUMA domain." The rest of the comments just echo the code.

Probably put ACPI_HANDLE above int and sort the int vars as 'int d, pxm'. This will save you a mail from Bruce later.

You can combine the test from above here which would mean that bus_generic_get_domain() is only called via a fall-through if you do:

if (h != NULL &&
    ACPI_SUCCESS(...))) {
        ...
}

As I suggested previously, you should make 'acpi_get_domain' non-static and re-use it here instead of duplicating.

Perhaps "Map a _PXM value to a VM domain".

This line isn't needed as it is already obvious from the #if test on the next line.

This is fine for testing, but shouldn't go into the commit. However, what I do think would be useful is to add a '%domain' sysctl node similar to '%desc', etc.

You could even only add that during device_add_child if bus_get_domain() is successful, and you can set it to the returned domain statically so the sysctl doesn't have to invoke BUS_GET_DOMAIN() each time it is called.

System administrators would much rather have a simple way ('sysctl dev.foo.0.%domain') to get this than having to do sed/awk magic on dmesg.boot.

s/PXM/_PXM/

Didn't see this earlier.. no need for extern for function prototypes. (We don't use it for other prototypes in the tree and in this file in particular.) You could also probably move these prototypes up into the earlier list (at least move acpi_get_domain up below acpi_MatchHid() perhaps).

I think printing it for ACPI and PCI makes sense, but it's not clear to me it make sense to print this on i2c buses, etc. I may work on the sysctl node today btw.

This could actually move up after bus_generic_get_dma_tag() as well.