[RFC V7 PATCH 00/19] memory-hotplug: hot-remove physical memory

From: Wen Congyang <wency <at> cn.fujitsu.com>

This patch series aims to support physical memory hot-remove.

The patches can free/remove the following things:

  - acpi_memory_info                          : [RFC PATCH 4/19]
  - /sys/firmware/memmap/X/{end, start, type} : [RFC PATCH 8/19]
  - iomem_resource                            : [RFC PATCH 9/19]
  - mem_section and related sysfs files       : [RFC PATCH 10-11, 13-16/19]
  - page table of removed memory              : [RFC PATCH 12/19]
  - node and related sysfs files              : [RFC PATCH 18-19/19]

If you find lack of function for physical memory hot-remove, please let me
know.

Known problems:
1. memory can't be offlined when CONFIG_MEMCG is selected.

change log of v7:
 [RFC PATCH v7 4/19]
   * do not continue if acpi_memory_device_remove_memory() fails.
 [RFC PATCH v7 15/19]
   * handle usemap in register_page_bootmem_info_section() too.

change log of v6:
 [RFC PATCH v6 12/19]
   * fix building error on other archtitectures than x86

 [RFC PATCH v6 15-16/19]