[PATCH v3 0/2] memory-hotplug: introduce CONFIG_HAVE_BOOTMEM_INFO_NODE and revert register_page_bootmem_info_node() when platform not support

[Lin Feng <linfeng@cn.fujitsu.com>]

Memory-hotplug codes for x86_64 have been implemented by patchset:
https://lkml.org/lkml/2013/1/9/124
While other platforms haven't been completely implemented yet.

If we enable both CONFIG_MEMORY_HOTPLUG_SPARSE and CONFIG_SPARSEMEM_VMEMMAP,
register_page_bootmem_info_node() may be buggy, which is a hotplug generic
function but falling back to call platform related function
register_page_bootmem_memmap().

Other platforms such as powerpc it's not implemented, so on such platforms,
revert them to empty as they were before.

It's implemented by adding a new Kconfig option named
CONFIG_HAVE_BOOTMEM_INFO_NODE, which will be automatically selected by
memory-hotplug supported archs(currently only on x86_64).

changeLog v2->v3:
1) patch 1/2:
- Rename the patch title to conform it's content.
- Update memory_hotplug.h and remove the misleading TODO pointed out by Michal.
2) patch 2/2:
- New added, remove unimplemented functions suggested by Michal.

ChangeLog v1->v2:
1) patch 1/2:
- Add a Kconfig option named HAVE_BOOTMEM_INFO_NODE suggested by Michal, which
  will be automatically selected by supported archs(currently only on x86_64).

Lin Feng (1):
  memory-hotplug: revert register_page_bootmem_info_node() to empty
    when platform related code is not implemented

Michal Hocko (1):
  memory-hotplug: cleanup: removing the arch specific functions without
    any implementation

 arch/ia64/mm/discontig.c       |    5 -----
 arch/powerpc/mm/init_64.c      |    5 -----
 arch/s390/mm/vmem.c            |    6 ------
 arch/sparc/mm/init_64.c        |    5 -----
 arch/x86/mm/init_64.c          |    2 +-
 include/linux/memory_hotplug.h |    6 ++++++
 mm/Kconfig                     |    8 ++++++++
 mm/memory_hotplug.c            |    2 ++
 8 files changed, 17 insertions(+), 22 deletions(-)