Problem description:

  We have additional_cpus= option for allocating possible_cpus.  But nid
  for possible cpus are not fixed at boot time.  cpus which is offlined at
  boot or cpus which is not on SRAT is not tied to its node.  This will
  cause panic at cpu onlining.

Usually, pxm_to_nid() mapping is fixed at boot time by SRAT.

But, unfortunately, some system (my system!) do not include
full SRAT table for possible cpus.  (Then, I use
additiona_cpus= option.)

For such possible cpus, pxm<->nid should be fixed at
hot-add.  We now have acpi_map_pxm_to_node() which is also
used at boot.  It's suitable here.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>