memcg: add null check to page_cgroup_zoneinfo()

[deliverable/linux.git] / include / linux / memcontrol.h

/* memcontrol.h - Memory Controller
 *
 * Copyright IBM Corporation, 2007
 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
 *
 * Copyright 2007 OpenVZ SWsoft Inc
 * Author: Pavel Emelianov <xemul@openvz.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#ifndef _LINUX_MEMCONTROL_H
#define _LINUX_MEMCONTROL_H
#include <linux/cgroup.h>
struct mem_cgroup;
struct page_cgroup;
struct page;
struct mm_struct;

#ifdef CONFIG_CGROUP_MEM_RES_CTLR
/*
 * All "charge" functions with gfp_mask should use GFP_KERNEL or
 * (gfp_mask & GFP_RECLAIM_MASK). In current implementatin, memcg doesn't
 * alloc memory but reclaims memory from all available zones. So, "where I want
 * memory from" bits of gfp_mask has no meaning. So any bits of that field is
 * available but adding a rule is better. charge functions' gfp_mask should
 * be set to GFP_KERNEL or gfp_mask & GFP_RECLAIM_MASK for avoiding ambiguous
 * codes.
 * (Of course, if memcg does memory allocation in future, GFP_KERNEL is sane.)
 */

extern int mem_cgroup_newpage_charge(struct page *page, struct mm_struct *mm,
				gfp_t gfp_mask);
/* for swap handling */
extern int mem_cgroup_try_charge(struct mm_struct *mm,
		gfp_t gfp_mask, struct mem_cgroup **ptr);
extern int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
		struct page *page, gfp_t mask, struct mem_cgroup **ptr);
extern void mem_cgroup_commit_charge_swapin(struct page *page,
					struct mem_cgroup *ptr);
extern void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *ptr);

extern int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
					gfp_t gfp_mask);
extern void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru);
extern void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru);
extern void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru);
extern void mem_cgroup_del_lru(struct page *page);
extern void mem_cgroup_move_lists(struct page *page,
				  enum lru_list from, enum lru_list to);
extern void mem_cgroup_uncharge_page(struct page *page);
extern void mem_cgroup_uncharge_cache_page(struct page *page);
extern int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask);

extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
					struct list_head *dst,
					unsigned long *scanned, int order,
					int mode, struct zone *z,
					struct mem_cgroup *mem_cont,
					int active, int file);
extern void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask);
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem);

extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);

static inline
int mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *cgroup)
{
	struct mem_cgroup *mem;
	rcu_read_lock();
	mem = mem_cgroup_from_task((mm)->owner);
	rcu_read_unlock();
	return cgroup == mem;
}

extern int
mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr);
extern void mem_cgroup_end_migration(struct mem_cgroup *mem,
	struct page *oldpage, struct page *newpage);

/*
 * For memory reclaim.
 */
extern int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem);
extern long mem_cgroup_reclaim_imbalance(struct mem_cgroup *mem);

extern int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem);
extern void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem,
							int priority);
extern void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem,
							int priority);

extern long mem_cgroup_calc_reclaim(struct mem_cgroup *mem, struct zone *zone,
					int priority, enum lru_list lru);

#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
extern int do_swap_account;
#endif

static inline bool mem_cgroup_disabled(void)
{
	if (mem_cgroup_subsys.disabled)
		return true;
	return false;
}

extern bool mem_cgroup_oom_called(struct task_struct *task);

#else /* CONFIG_CGROUP_MEM_RES_CTLR */
struct mem_cgroup;

static inline int mem_cgroup_newpage_charge(struct page *page,
					struct mm_struct *mm, gfp_t gfp_mask)
{
	return 0;
}

static inline int mem_cgroup_cache_charge(struct page *page,
					struct mm_struct *mm, gfp_t gfp_mask)
{
	return 0;
}

static inline int mem_cgroup_try_charge(struct mm_struct *mm,
			gfp_t gfp_mask, struct mem_cgroup **ptr)
{
	return 0;
}

static inline int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
		struct page *page, gfp_t gfp_mask, struct mem_cgroup **ptr)
{
	return 0;
}

static inline void mem_cgroup_commit_charge_swapin(struct page *page,
					  struct mem_cgroup *ptr)
{
}

static inline void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *ptr)
{
}

static inline void mem_cgroup_uncharge_page(struct page *page)
{
}

static inline void mem_cgroup_uncharge_cache_page(struct page *page)
{
}

static inline int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)
{
	return 0;
}

static inline void mem_cgroup_add_lru_list(struct page *page, int lru)
{
}

static inline void mem_cgroup_del_lru_list(struct page *page, int lru)
{
	return ;
}

static inline void mem_cgroup_rotate_lru_list(struct page *page, int lru)
{
	return ;
}

static inline void mem_cgroup_del_lru(struct page *page)
{
	return ;
}

static inline void
mem_cgroup_move_lists(struct page *page, enum lru_list from, enum lru_list to)
{
}

static inline int mm_match_cgroup(struct mm_struct *mm, struct mem_cgroup *mem)
{
	return 1;
}

static inline int task_in_mem_cgroup(struct task_struct *task,
				     const struct mem_cgroup *mem)
{
	return 1;
}

static inline int
mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
{
	return 0;
}

static inline void mem_cgroup_end_migration(struct mem_cgroup *mem,
					struct page *oldpage,
					struct page *newpage)
{
}

static inline int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem)
{
	return 0;
}

static inline int mem_cgroup_reclaim_imbalance(struct mem_cgroup *mem)
{
	return 0;
}

static inline int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
{
	return 0;
}

static inline void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem,
						int priority)
{
}

static inline void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem,
						int priority)
{
}

static inline long mem_cgroup_calc_reclaim(struct mem_cgroup *mem,
					struct zone *zone, int priority,
					enum lru_list lru)
{
	return 0;
}

static inline bool mem_cgroup_disabled(void)
{
	return true;
}

static inline bool mem_cgroup_oom_called(struct task_struct *task)
{
	return false;
}
#endif /* CONFIG_CGROUP_MEM_CONT */

#endif /* _LINUX_MEMCONTROL_H */