include/linux/hugetlb_cgroup.h

/*
 * 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/res_counter.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(!PageHuge(page));

	if (compound_order(page) < HUGETLB_CGROUP_MIN_ORDER)
		return NULL;
	return (struct hugetlb_cgroup *)page[2].lru.next;
}

static inline
int set_hugetlb_cgroup(struct page *page, struct hugetlb_cgroup *h_cg)
{
	VM_BUG_ON(!PageHuge(page));

	if (compound_order(page) < HUGETLB_CGROUP_MIN_ORDER)
		return -1;
	page[2].lru.next = (void *)h_cg;
	return 0;
}

static inline bool hugetlb_cgroup_disabled(void)
{
	if (hugetlb_subsys.disabled)
		return true;
	return false;
}

#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;
}

#endif  /* CONFIG_MEM_RES_CTLR_HUGETLB */
#endif