Memory controller: add per cgroup LRU and reclaim

Memory controller: add per cgroup LRU and reclaim

Add the page_cgroup to the per cgroup LRU.  The reclaim algorithm has
been modified to make the isolate_lru_pages() as a pluggable component.  The
scan_control data structure now accepts the cgroup on behalf of which
reclaims are carried out.  try_to_free_pages() has been extended to become
cgroup aware.

[[email protected]: fix warning]
[[email protected]: initialize all scan_control's isolate_pages member]
[[email protected]: make do_try_to_free_pages() static]
[[email protected]: memcgroup: fix try_to_free order]
[[email protected]: this unlock_page_cgroup() is unnecessary]
Signed-off-by: Pavel Emelianov <[email protected]>
Signed-off-by: Balbir Singh <[email protected]>
Cc: Paul Menage <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Cc: Nick Piggin <[email protected]>
Cc: Kirill Korotaev <[email protected]>
Cc: Herbert Poetzl <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Vaidyanathan Srinivasan <[email protected]>
Signed-off-by: Lee Schermerhorn <[email protected]>
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: KAMEZAWA Hiroyuki <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>