hugetlb/cgroup: add charge/uncharge routines for hugetlb cgroup

hugetlb/cgroup: add charge/uncharge routines for hugetlb cgroup

Add the charge and uncharge routines for hugetlb cgroup.  We do cgroup
charging in page alloc and uncharge in compound page destructor.
Assigning page's hugetlb cgroup is protected by hugetlb_lock.

[[email protected]: add huge_page_order check to avoid incorrect uncharge]
Signed-off-by: Aneesh Kumar K.V <[email protected]>
Cc: David Rientjes <[email protected]>
Acked-by: KAMEZAWA Hiroyuki <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: KOSAKI Motohiro <[email protected]>
Signed-off-by: Aneesh Kumar K.V <[email protected]>
Signed-off-by: Wanpeng Li <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>