per-zone and reclaim enhancements for memory controller: per zone lru for cgroup

per-zone and reclaim enhancements for memory controller: per zone lru for cgroup

This patch implements per-zone lru for memory cgroup.
This patch makes use of mem_cgroup_per_zone struct for per zone lru.

LRU can be accessed by

   mz = mem_cgroup_zoneinfo(mem_cgroup, node, zone);
   &mz->active_list
   &mz->inactive_list

   or
   mz = page_cgroup_zoneinfo(page_cgroup);
   &mz->active_list
   &mz->inactive_list

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Paul Menage <menage@google.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>