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 * 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;
struct resv_map;
struct file_region;

#ifdef CONFIG_CGROUP_HUGETLB
/*
 * Minimum page order trackable by hugetlb cgroup.
 * At least 3 pages are necessary for all the tracking information.
 * The second tail page contains all of the hugetlb-specific fields.
 */
#define HUGETLB_CGROUP_MIN_ORDER order_base_2(__NR_USED_SUBPAGE)

enum hugetlb_memory_event {
	HUGETLB_MAX,
	HUGETLB_NR_MEMORY_EVENTS,
};

struct hugetlb_cgroup_per_node {
	/* hugetlb usage in pages over all hstates. */
	unsigned long usage[HUGE_MAX_HSTATE];
};

struct hugetlb_cgroup {
	struct cgroup_subsys_state css;

	/*
	 * the counter to account for hugepages from hugetlb.
	 */
	struct page_counter hugepage[HUGE_MAX_HSTATE];

	/*
	 * the counter to account for hugepage reservations from hugetlb.
	 */
	struct page_counter rsvd_hugepage[HUGE_MAX_HSTATE];

	atomic_long_t events[HUGE_MAX_HSTATE][HUGETLB_NR_MEMORY_EVENTS];
	atomic_long_t events_local[HUGE_MAX_HSTATE][HUGETLB_NR_MEMORY_EVENTS];

	/* Handle for "hugetlb.events" */
	struct cgroup_file events_file[HUGE_MAX_HSTATE];

	/* Handle for "hugetlb.events.local" */
	struct cgroup_file events_local_file[HUGE_MAX_HSTATE];

	struct hugetlb_cgroup_per_node *nodeinfo[];
};

static inline struct hugetlb_cgroup *
__hugetlb_cgroup_from_folio(struct folio *folio, bool rsvd)
{
	VM_BUG_ON_FOLIO(!folio_test_hugetlb(folio), folio);
	if (folio_order(folio) < HUGETLB_CGROUP_MIN_ORDER)
		return NULL;
	if (rsvd)
		return folio->_hugetlb_cgroup_rsvd;
	else
		return folio->_hugetlb_cgroup;
}

static inline struct hugetlb_cgroup *hugetlb_cgroup_from_folio(struct folio *folio)
{
	return __hugetlb_cgroup_from_folio(folio, false);
}

static inline struct hugetlb_cgroup *
hugetlb_cgroup_from_folio_rsvd(struct folio *folio)
{
	return __hugetlb_cgroup_from_folio(folio, true);
}

static inline void __set_hugetlb_cgroup(struct folio *folio,
				       struct hugetlb_cgroup *h_cg, bool rsvd)
{
	VM_BUG_ON_FOLIO(!folio_test_hugetlb(folio), folio);
	if (folio_order(folio) < HUGETLB_CGROUP_MIN_ORDER)
		return;
	if (rsvd)
		folio->_hugetlb_cgroup_rsvd = h_cg;
	else
		folio->_hugetlb_cgroup = h_cg;
}

static inline void set_hugetlb_cgroup(struct folio *folio,
				     struct hugetlb_cgroup *h_cg)
{
	__set_hugetlb_cgroup(folio, h_cg, false);
}

static inline void set_hugetlb_cgroup_rsvd(struct folio *folio,
					  struct hugetlb_cgroup *h_cg)
{
	__set_hugetlb_cgroup(folio, h_cg, true);
}

static inline bool hugetlb_cgroup_disabled(void)
{
	return !cgroup_subsys_enabled(hugetlb_cgrp_subsys);
}

static inline void hugetlb_cgroup_put_rsvd_cgroup(struct hugetlb_cgroup *h_cg)
{
	css_put(&h_cg->css);
}

static inline void resv_map_dup_hugetlb_cgroup_uncharge_info(
						struct resv_map *resv_map)
{
	if (resv_map->css)
		css_get(resv_map->css);
}

static inline void resv_map_put_hugetlb_cgroup_uncharge_info(
						struct resv_map *resv_map)
{
	if (resv_map->css)
		css_put(resv_map->css);
}

extern int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
					struct hugetlb_cgroup **ptr);
extern int hugetlb_cgroup_charge_cgroup_rsvd(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 folio *folio);
extern void hugetlb_cgroup_commit_charge_rsvd(int idx, unsigned long nr_pages,
					      struct hugetlb_cgroup *h_cg,
					      struct folio