File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/include/linux/hugetlb_cgroup.h b/include/linux/hugetlb_cgroup.h
new file mode 100644
index 0000000..24154c2
--- /dev/null
+++ b/include/linux/hugetlb_cgroup.h
@@ -0,0 +1,123 @@
+/*
+ * Copyright IBM Corporation, 2012
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#ifndef _LINUX_HUGETLB_CGROUP_H
+#define _LINUX_HUGETLB_CGROUP_H
+
+#include <linux/mmdebug.h>
+
+struct hugetlb_cgroup;
+/*
+ * Minimum page order trackable by hugetlb cgroup.
+ * At least 3 pages are necessary for all the tracking information.
+ */
+#define HUGETLB_CGROUP_MIN_ORDER	2
+
+#ifdef CONFIG_CGROUP_HUGETLB
+
+static inline struct hugetlb_cgroup *hugetlb_cgroup_from_page(struct page *page)
+{
+	VM_BUG_ON_PAGE(!PageHuge(page), page);
+
+	if (compound_order(page) < HUGETLB_CGROUP_MIN_ORDER)
+		return NULL;
+	return (struct hugetlb_cgroup *)page[2].private;
+}
+
+static inline
+int set_hugetlb_cgroup(struct page *page, struct hugetlb_cgroup *h_cg)
+{
+	VM_BUG_ON_PAGE(!PageHuge(page), page);
+
+	if (compound_order(page) < HUGETLB_CGROUP_MIN_ORDER)
+		return -1;
+	page[2].private	= (unsigned long)h_cg;
+	return 0;
+}
+
+static inline bool hugetlb_cgroup_disabled(void)
+{
+	return !cgroup_subsys_enabled(hugetlb_cgrp_subsys);
+}
+
+extern int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
+					struct hugetlb_cgroup **ptr);
+extern void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
+					 struct hugetlb_cgroup *h_cg,
+					 struct page *page);
+extern void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages,
+					 struct page *page);
+extern void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
+					   struct hugetlb_cgroup *h_cg);
+extern void hugetlb_cgroup_file_init(void) __init;
+extern void hugetlb_cgroup_migrate(struct page *oldhpage,
+				   struct page *newhpage);
+
+#else
+static inline struct hugetlb_cgroup *hugetlb_cgroup_from_page(struct page *page)
+{
+	return NULL;
+}
+
+static inline
+int set_hugetlb_cgroup(struct page *page, struct hugetlb_cgroup *h_cg)
+{
+	return 0;
+}
+
+static inline bool hugetlb_cgroup_disabled(void)
+{
+	return true;
+}
+
+static inline int
+hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
+			     struct hugetlb_cgroup **ptr)
+{
+	return 0;
+}
+
+static inline void
+hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
+			     struct hugetlb_cgroup *h_cg,
+			     struct page *page)
+{
+	return;
+}
+
+static inline void
+hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages, struct page *page)
+{
+	return;
+}
+
+static inline void
+hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
+			       struct hugetlb_cgroup *h_cg)
+{
+	return;
+}
+
+static inline void hugetlb_cgroup_file_init(void)
+{
+}
+
+static inline void hugetlb_cgroup_migrate(struct page *oldhpage,
+					  struct page *newhpage)
+{
+	return;
+}
+
+#endif  /* CONFIG_MEM_RES_CTLR_HUGETLB */
+#endif