memory hotplug prototype for ia64

Hello,

This set of 2 patches make Iwamoto-san's memory hotplug prototype correspond to an IPF NUMA machines. The patch is against linux 2.6.5 and works with Iwamoto-san's memory hotplug patch.

I don't have an IPF NUMA machine. So, I tested on Tiger4 (intel's IPF machine) with NUMA node
in emulation.

Changes from Iwamoto-san's patches are:

- Using SRAT for NUMA node.
- Structures of all nodes are initialized at boot. In Iwamoto-san's patch, node0 is initialized at boot, and after boot, all nodes except node0 are initialized by hot-add operation.

Patch Details:

- Patch(1/2) memory hotplug prototype for ia64 The main patch.
- Patch(2/2) NUMA node emulation
To emulate NUMA node on non-NUMA machines.

Remainder items:

The following items are being made.
- Support of HotAdd function.
- Correspond to ACPI's SLIT.
So, it does not use find_next_best_node() function (mm/page_alloc.c) which added to linux 2.6.5.
- Support of hugetlbpage.

How to apply:

1) First of all, apply Iwamoto-san's patches.
2) Apply this set of patches.

Thank you,
Fumihiro Terasawa.