memcontrol.c 143.3 KB
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/* memcontrol.c - Memory Controller
 *
 * Copyright IBM Corporation, 2007
 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
 *
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 * Copyright 2007 OpenVZ SWsoft Inc
 * Author: Pavel Emelianov <xemul@openvz.org>
 *
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 * Memory thresholds
 * Copyright (C) 2009 Nokia Corporation
 * Author: Kirill A. Shutemov
 *
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 * 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.
 */

#include <linux/res_counter.h>
#include <linux/memcontrol.h>
#include <linux/cgroup.h>
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <linux/pagemap.h>
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#include <linux/smp.h>
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#include <linux/page-flags.h>
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#include <linux/backing-dev.h>
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#include <linux/bit_spinlock.h>
#include <linux/rcupdate.h>
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#include <linux/limits.h>
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#include <linux/export.h>
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#include <linux/mutex.h>
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#include <linux/rbtree.h>
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#include <linux/slab.h>
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#include <linux/swap.h>
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#include <linux/swapops.h>
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#include <linux/spinlock.h>
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#include <linux/eventfd.h>
#include <linux/sort.h>
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#include <linux/fs.h>
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#include <linux/seq_file.h>
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#include <linux/vmalloc.h>
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#include <linux/mm_inline.h>
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#include <linux/page_cgroup.h>
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#include <linux/cpu.h>
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#include <linux/oom.h>
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#include "internal.h"
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#include <net/sock.h>
#include <net/tcp_memcontrol.h>
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#include <asm/uaccess.h>

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#include <trace/events/vmscan.h>

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struct cgroup_subsys mem_cgroup_subsys __read_mostly;
#define MEM_CGROUP_RECLAIM_RETRIES	5
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struct mem_cgroup *root_mem_cgroup __read_mostly;
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#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
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/* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
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int do_swap_account __read_mostly;
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/* for remember boot option*/
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED
static int really_do_swap_account __initdata = 1;
#else
static int really_do_swap_account __initdata = 0;
#endif

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#else
#define do_swap_account		(0)
#endif


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/*
 * Statistics for memory cgroup.
 */
enum mem_cgroup_stat_index {
	/*
	 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
	 */
	MEM_CGROUP_STAT_CACHE, 	   /* # of pages charged as cache */
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	MEM_CGROUP_STAT_RSS,	   /* # of pages charged as anon rss */
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	MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */
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	MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
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	MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */
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	MEM_CGROUP_ON_MOVE,	/* someone is moving account between groups */
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	MEM_CGROUP_STAT_NSTATS,
};

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enum mem_cgroup_events_index {
	MEM_CGROUP_EVENTS_PGPGIN,	/* # of pages paged in */
	MEM_CGROUP_EVENTS_PGPGOUT,	/* # of pages paged out */
	MEM_CGROUP_EVENTS_COUNT,	/* # of pages paged in/out */
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	MEM_CGROUP_EVENTS_PGFAULT,	/* # of page-faults */
	MEM_CGROUP_EVENTS_PGMAJFAULT,	/* # of major page-faults */
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	MEM_CGROUP_EVENTS_NSTATS,
};
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/*
 * Per memcg event counter is incremented at every pagein/pageout. With THP,
 * it will be incremated by the number of pages. This counter is used for
 * for trigger some periodic events. This is straightforward and better
 * than using jiffies etc. to handle periodic memcg event.
 */
enum mem_cgroup_events_target {
	MEM_CGROUP_TARGET_THRESH,
	MEM_CGROUP_TARGET_SOFTLIMIT,
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	MEM_CGROUP_TARGET_NUMAINFO,
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	MEM_CGROUP_NTARGETS,
};
#define THRESHOLDS_EVENTS_TARGET (128)
#define SOFTLIMIT_EVENTS_TARGET (1024)
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#define NUMAINFO_EVENTS_TARGET	(1024)
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struct mem_cgroup_stat_cpu {
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	long count[MEM_CGROUP_STAT_NSTATS];
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	unsigned long events[MEM_CGROUP_EVENTS_NSTATS];
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	unsigned long targets[MEM_CGROUP_NTARGETS];
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};

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struct mem_cgroup_reclaim_iter {
	/* css_id of the last scanned hierarchy member */
	int position;
	/* scan generation, increased every round-trip */
	unsigned int generation;
};

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/*
 * per-zone information in memory controller.
 */
struct mem_cgroup_per_zone {
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	struct lruvec		lruvec;
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	unsigned long		count[NR_LRU_LISTS];
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	struct mem_cgroup_reclaim_iter reclaim_iter[DEF_PRIORITY + 1];

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	struct zone_reclaim_stat reclaim_stat;
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	struct rb_node		tree_node;	/* RB tree node */
	unsigned long long	usage_in_excess;/* Set to the value by which */
						/* the soft limit is exceeded*/
	bool			on_tree;
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	struct mem_cgroup	*mem;		/* Back pointer, we cannot */
						/* use container_of	   */
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};
/* Macro for accessing counter */
#define MEM_CGROUP_ZSTAT(mz, idx)	((mz)->count[(idx)])

struct mem_cgroup_per_node {
	struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
};

struct mem_cgroup_lru_info {
	struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES];
};

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/*
 * Cgroups above their limits are maintained in a RB-Tree, independent of
 * their hierarchy representation
 */

struct mem_cgroup_tree_per_zone {
	struct rb_root rb_root;
	spinlock_t lock;
};

struct mem_cgroup_tree_per_node {
	struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
};

struct mem_cgroup_tree {
	struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
};

static struct mem_cgroup_tree soft_limit_tree __read_mostly;

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struct mem_cgroup_threshold {
	struct eventfd_ctx *eventfd;
	u64 threshold;
};

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/* For threshold */
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struct mem_cgroup_threshold_ary {
	/* An array index points to threshold just below usage. */
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	int current_threshold;
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	/* Size of entries[] */
	unsigned int size;
	/* Array of thresholds */
	struct mem_cgroup_threshold entries[0];
};
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struct mem_cgroup_thresholds {
	/* Primary thresholds array */
	struct mem_cgroup_threshold_ary *primary;
	/*
	 * Spare threshold array.
	 * This is needed to make mem_cgroup_unregister_event() "never fail".
	 * It must be able to store at least primary->size - 1 entries.
	 */
	struct mem_cgroup_threshold_ary *spare;
};

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/* for OOM */
struct mem_cgroup_eventfd_list {
	struct list_head list;
	struct eventfd_ctx *eventfd;
};
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static void mem_cgroup_threshold(struct mem_cgroup *memcg);
static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
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/*
 * The memory controller data structure. The memory controller controls both
 * page cache and RSS per cgroup. We would eventually like to provide
 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
 * to help the administrator determine what knobs to tune.
 *
 * TODO: Add a water mark for the memory controller. Reclaim will begin when
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 * we hit the water mark. May be even add a low water mark, such that
 * no reclaim occurs from a cgroup at it's low water mark, this is
 * a feature that will be implemented much later in the future.
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 */
struct mem_cgroup {
	struct cgroup_subsys_state css;
	/*
	 * the counter to account for memory usage
	 */
	struct res_counter res;
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	union {
		/*
		 * the counter to account for mem+swap usage.
		 */
		struct res_counter memsw;

		/*
		 * rcu_freeing is used only when freeing struct mem_cgroup,
		 * so put it into a union to avoid wasting more memory.
		 * It must be disjoint from the css field.  It could be
		 * in a union with the res field, but res plays a much
		 * larger part in mem_cgroup life than memsw, and might
		 * be of interest, even at time of free, when debugging.
		 * So share rcu_head with the less interesting memsw.
		 */
		struct rcu_head rcu_freeing;
		/*
		 * But when using vfree(), that cannot be done at
		 * interrupt time, so we must then queue the work.
		 */
		struct work_struct work_freeing;
	};

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	/*
	 * Per cgroup active and inactive list, similar to the
	 * per zone LRU lists.
	 */
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	struct mem_cgroup_lru_info info;
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	int last_scanned_node;
#if MAX_NUMNODES > 1
	nodemask_t	scan_nodes;
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	atomic_t	numainfo_events;
	atomic_t	numainfo_updating;
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#endif
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	/*
	 * Should the accounting and control be hierarchical, per subtree?
	 */
	bool use_hierarchy;
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	bool		oom_lock;
	atomic_t	under_oom;

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	atomic_t	refcnt;
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	int	swappiness;
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	/* OOM-Killer disable */
	int		oom_kill_disable;
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	/* set when res.limit == memsw.limit */
	bool		memsw_is_minimum;

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	/* protect arrays of thresholds */
	struct mutex thresholds_lock;

	/* thresholds for memory usage. RCU-protected */
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	struct mem_cgroup_thresholds thresholds;
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	/* thresholds for mem+swap usage. RCU-protected */
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	struct mem_cgroup_thresholds memsw_thresholds;
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	/* For oom notifier event fd */
	struct list_head oom_notify;
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	/*
	 * Should we move charges of a task when a task is moved into this
	 * mem_cgroup ? And what type of charges should we move ?
	 */
	unsigned long 	move_charge_at_immigrate;
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	/*
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	 * percpu counter.
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	 */
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	struct mem_cgroup_stat_cpu *stat;
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	/*
	 * used when a cpu is offlined or other synchronizations
	 * See mem_cgroup_read_stat().
	 */
	struct mem_cgroup_stat_cpu nocpu_base;
	spinlock_t pcp_counter_lock;
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#ifdef CONFIG_INET
	struct tcp_memcontrol tcp_mem;
#endif
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};

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/* Stuffs for move charges at task migration. */
/*
 * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a
 * left-shifted bitmap of these types.
 */
enum move_type {
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	MOVE_CHARGE_TYPE_ANON,	/* private anonymous page and swap of it */
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	MOVE_CHARGE_TYPE_FILE,	/* file page(including tmpfs) and swap of it */
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	NR_MOVE_TYPE,
};

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/* "mc" and its members are protected by cgroup_mutex */
static struct move_charge_struct {
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	spinlock_t	  lock; /* for from, to */
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	struct mem_cgroup *from;
	struct mem_cgroup *to;
	unsigned long precharge;
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	unsigned long moved_charge;
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	unsigned long moved_swap;
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	struct task_struct *moving_task;	/* a task moving charges */
	wait_queue_head_t waitq;		/* a waitq for other context */
} mc = {
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	.lock = __SPIN_LOCK_UNLOCKED(mc.lock),
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	.waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
};
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static bool move_anon(void)
{
	return test_bit(MOVE_CHARGE_TYPE_ANON,
					&mc.to->move_charge_at_immigrate);
}

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static bool move_file(void)
{
	return test_bit(MOVE_CHARGE_TYPE_FILE,
					&mc.to->move_charge_at_immigrate);
}

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/*
 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
 * limit reclaim to prevent infinite loops, if they ever occur.
 */
#define	MEM_CGROUP_MAX_RECLAIM_LOOPS		(100)
#define	MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS	(2)

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enum charge_type {
	MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
	MEM_CGROUP_CHARGE_TYPE_MAPPED,
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	MEM_CGROUP_CHARGE_TYPE_SHMEM,	/* used by page migration of shmem */
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	MEM_CGROUP_CHARGE_TYPE_FORCE,	/* used by force_empty */
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	MEM_CGROUP_CHARGE_TYPE_SWAPOUT,	/* for accounting swapcache */
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	MEM_CGROUP_CHARGE_TYPE_DROP,	/* a page was unused swap cache */
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	NR_CHARGE_TYPE,
};

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/* for encoding cft->private value on file */
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#define _MEM			(0)
#define _MEMSWAP		(1)
#define _OOM_TYPE		(2)
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#define MEMFILE_PRIVATE(x, val)	(((x) << 16) | (val))
#define MEMFILE_TYPE(val)	(((val) >> 16) & 0xffff)
#define MEMFILE_ATTR(val)	((val) & 0xffff)
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/* Used for OOM nofiier */
#define OOM_CONTROL		(0)
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/*
 * Reclaim flags for mem_cgroup_hierarchical_reclaim
 */
#define MEM_CGROUP_RECLAIM_NOSWAP_BIT	0x0
#define MEM_CGROUP_RECLAIM_NOSWAP	(1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
#define MEM_CGROUP_RECLAIM_SHRINK_BIT	0x1
#define MEM_CGROUP_RECLAIM_SHRINK	(1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)

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static void mem_cgroup_get(struct mem_cgroup *memcg);
static void mem_cgroup_put(struct mem_cgroup *memcg);
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/* Writing them here to avoid exposing memcg's inner layout */
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
#include <net/sock.h>
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#include <net/ip.h>
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static bool mem_cgroup_is_root(struct mem_cgroup *memcg);
void sock_update_memcg(struct sock *sk)
{
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	if (mem_cgroup_sockets_enabled) {
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		struct mem_cgroup *memcg;

		BUG_ON(!sk->sk_prot->proto_cgroup);

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		/* Socket cloning can throw us here with sk_cgrp already
		 * filled. It won't however, necessarily happen from
		 * process context. So the test for root memcg given
		 * the current task's memcg won't help us in this case.
		 *
		 * Respecting the original socket's memcg is a better
		 * decision in this case.
		 */
		if (sk->sk_cgrp) {
			BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg));
			mem_cgroup_get(sk->sk_cgrp->memcg);
			return;
		}

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		rcu_read_lock();
		memcg = mem_cgroup_from_task(current);
		if (!mem_cgroup_is_root(memcg)) {
			mem_cgroup_get(memcg);
			sk->sk_cgrp = sk->sk_prot->proto_cgroup(memcg);
		}
		rcu_read_unlock();
	}
}
EXPORT_SYMBOL(sock_update_memcg);

void sock_release_memcg(struct sock *sk)
{
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	if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
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		struct mem_cgroup *memcg;
		WARN_ON(!sk->sk_cgrp->memcg);
		memcg = sk->sk_cgrp->memcg;
		mem_cgroup_put(memcg);
	}
}
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#ifdef CONFIG_INET
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struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
{
	if (!memcg || mem_cgroup_is_root(memcg))
		return NULL;

	return &memcg->tcp_mem.cg_proto;
}
EXPORT_SYMBOL(tcp_proto_cgroup);
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#endif /* CONFIG_INET */
#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */

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static void drain_all_stock_async(struct mem_cgroup *memcg);
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static struct mem_cgroup_per_zone *
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mem_cgroup_zoneinfo(struct mem_cgroup *memcg, int nid, int zid)
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{
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	return &memcg->info.nodeinfo[nid]->zoneinfo[zid];
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}

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struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg)
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{
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	return &memcg->css;
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}

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static struct mem_cgroup_per_zone *
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page_cgroup_zoneinfo(struct mem_cgroup *memcg, struct page *page)
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{
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	int nid = page_to_nid(page);
	int zid = page_zonenum(page);
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	return mem_cgroup_zoneinfo(memcg, nid, zid);
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}

static struct mem_cgroup_tree_per_zone *
soft_limit_tree_node_zone(int nid, int zid)
{
	return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
}

static struct mem_cgroup_tree_per_zone *
soft_limit_tree_from_page(struct page *page)
{
	int nid = page_to_nid(page);
	int zid = page_zonenum(page);

	return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
}

static void
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__mem_cgroup_insert_exceeded(struct mem_cgroup *memcg,
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				struct mem_cgroup_per_zone *mz,
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				struct mem_cgroup_tree_per_zone *mctz,
				unsigned long long new_usage_in_excess)
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{
	struct rb_node **p = &mctz->rb_root.rb_node;
	struct rb_node *parent = NULL;
	struct mem_cgroup_per_zone *mz_node;

	if (mz->on_tree)
		return;

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	mz->usage_in_excess = new_usage_in_excess;
	if (!mz->usage_in_excess)
		return;
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	while (*p) {
		parent = *p;
		mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
					tree_node);
		if (mz->usage_in_excess < mz_node->usage_in_excess)
			p = &(*p)->rb_left;
		/*
		 * We can't avoid mem cgroups that are over their soft
		 * limit by the same amount
		 */
		else if (mz->usage_in_excess >= mz_node->usage_in_excess)
			p = &(*p)->rb_right;
	}
	rb_link_node(&mz->tree_node, parent, p);
	rb_insert_color(&mz->tree_node, &mctz->rb_root);
	mz->on_tree = true;
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}

static void
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__mem_cgroup_remove_exceeded(struct mem_cgroup *memcg,
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				struct mem_cgroup_per_zone *mz,
				struct mem_cgroup_tree_per_zone *mctz)
{
	if (!mz->on_tree)
		return;
	rb_erase(&mz->tree_node, &mctz->rb_root);
	mz->on_tree = false;
}

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static void
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mem_cgroup_remove_exceeded(struct mem_cgroup *memcg,
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				struct mem_cgroup_per_zone *mz,
				struct mem_cgroup_tree_per_zone *mctz)
{
	spin_lock(&mctz->lock);
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	__mem_cgroup_remove_exceeded(memcg, mz, mctz);
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	spin_unlock(&mctz->lock);
}


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static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
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{
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	unsigned long long excess;
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	struct mem_cgroup_per_zone *mz;
	struct mem_cgroup_tree_per_zone *mctz;
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	int nid = page_to_nid(page);
	int zid = page_zonenum(page);
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	mctz = soft_limit_tree_from_page(page);

	/*
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	 * Necessary to update all ancestors when hierarchy is used.
	 * because their event counter is not touched.
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	 */
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	for (; memcg; memcg = parent_mem_cgroup(memcg)) {
		mz = mem_cgroup_zoneinfo(memcg, nid, zid);
		excess = res_counter_soft_limit_excess(&memcg->res);
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		/*
		 * We have to update the tree if mz is on RB-tree or
		 * mem is over its softlimit.
		 */
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		if (excess || mz->on_tree) {
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			spin_lock(&mctz->lock);
			/* if on-tree, remove it */
			if (mz->on_tree)
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				__mem_cgroup_remove_exceeded(memcg, mz, mctz);
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			/*
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			 * Insert again. mz->usage_in_excess will be updated.
			 * If excess is 0, no tree ops.
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			 */
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			__mem_cgroup_insert_exceeded(memcg, mz, mctz, excess);
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			spin_unlock(&mctz->lock);
		}
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	}
}

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static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
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{
	int node, zone;
	struct mem_cgroup_per_zone *mz;
	struct mem_cgroup_tree_per_zone *mctz;

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	for_each_node(node) {
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		for (zone = 0; zone < MAX_NR_ZONES; zone++) {
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			mz = mem_cgroup_zoneinfo(memcg, node, zone);
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			mctz = soft_limit_tree_node_zone(node, zone);
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			mem_cgroup_remove_exceeded(memcg, mz, mctz);
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		}
	}
}

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static struct mem_cgroup_per_zone *
__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
{
	struct rb_node *rightmost = NULL;
601
	struct mem_cgroup_per_zone *mz;
602 603

retry:
604
	mz = NULL;
605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633
	rightmost = rb_last(&mctz->rb_root);
	if (!rightmost)
		goto done;		/* Nothing to reclaim from */

	mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
	/*
	 * Remove the node now but someone else can add it back,
	 * we will to add it back at the end of reclaim to its correct
	 * position in the tree.
	 */
	__mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
	if (!res_counter_soft_limit_excess(&mz->mem->res) ||
		!css_tryget(&mz->mem->css))
		goto retry;
done:
	return mz;
}

static struct mem_cgroup_per_zone *
mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
{
	struct mem_cgroup_per_zone *mz;

	spin_lock(&mctz->lock);
	mz = __mem_cgroup_largest_soft_limit_node(mctz);
	spin_unlock(&mctz->lock);
	return mz;
}

634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652
/*
 * Implementation Note: reading percpu statistics for memcg.
 *
 * Both of vmstat[] and percpu_counter has threshold and do periodic
 * synchronization to implement "quick" read. There are trade-off between
 * reading cost and precision of value. Then, we may have a chance to implement
 * a periodic synchronizion of counter in memcg's counter.
 *
 * But this _read() function is used for user interface now. The user accounts
 * memory usage by memory cgroup and he _always_ requires exact value because
 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
 * have to visit all online cpus and make sum. So, for now, unnecessary
 * synchronization is not implemented. (just implemented for cpu hotplug)
 *
 * If there are kernel internal actions which can make use of some not-exact
 * value, and reading all cpu value can be performance bottleneck in some
 * common workload, threashold and synchonization as vmstat[] should be
 * implemented.
 */
653
static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
654
				 enum mem_cgroup_stat_index idx)
655
{
656
	long val = 0;
657 658
	int cpu;

659 660
	get_online_cpus();
	for_each_online_cpu(cpu)
661
		val += per_cpu(memcg->stat->count[idx], cpu);
662
#ifdef CONFIG_HOTPLUG_CPU
663 664 665
	spin_lock(&memcg->pcp_counter_lock);
	val += memcg->nocpu_base.count[idx];
	spin_unlock(&memcg->pcp_counter_lock);
666 667
#endif
	put_online_cpus();
668 669 670
	return val;
}

671
static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
672 673 674
					 bool charge)
{
	int val = (charge) ? 1 : -1;
675
	this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAPOUT], val);
676 677
}

678
static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
679 680 681 682 683 684
					    enum mem_cgroup_events_index idx)
{
	unsigned long val = 0;
	int cpu;

	for_each_online_cpu(cpu)
685
		val += per_cpu(memcg->stat->events[idx], cpu);
686
#ifdef CONFIG_HOTPLUG_CPU
687 688 689
	spin_lock(&memcg->pcp_counter_lock);
	val += memcg->nocpu_base.events[idx];
	spin_unlock(&memcg->pcp_counter_lock);
690 691 692 693
#endif
	return val;
}

694
static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
695
					 bool file, int nr_pages)
696
{
697 698
	preempt_disable();

699
	if (file)
700 701
		__this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE],
				nr_pages);
702
	else
703 704
		__this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS],
				nr_pages);
705

706 707
	/* pagein of a big page is an event. So, ignore page size */
	if (nr_pages > 0)
708
		__this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
709
	else {
710
		__this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
711 712
		nr_pages = -nr_pages; /* for event */
	}
713

714
	__this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_COUNT], nr_pages);
715

716
	preempt_enable();
717 718
}

719
unsigned long
720
mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid,
721
			unsigned int lru_mask)
722 723
{
	struct mem_cgroup_per_zone *mz;
724 725 726
	enum lru_list l;
	unsigned long ret = 0;

727
	mz = mem_cgroup_zoneinfo(memcg, nid, zid);
728 729 730 731 732 733 734 735 736

	for_each_lru(l) {
		if (BIT(l) & lru_mask)
			ret += MEM_CGROUP_ZSTAT(mz, l);
	}
	return ret;
}

static unsigned long
737
mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
738 739
			int nid, unsigned int lru_mask)
{
740 741 742
	u64 total = 0;
	int zid;

743
	for (zid = 0; zid < MAX_NR_ZONES; zid++)
744 745
		total += mem_cgroup_zone_nr_lru_pages(memcg,
						nid, zid, lru_mask);
746

747 748
	return total;
}
749

750
static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
751
			unsigned int lru_mask)
752
{
753
	int nid;
754 755
	u64 total = 0;

756
	for_each_node_state(nid, N_HIGH_MEMORY)
757
		total += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask);
758
	return total;
759 760
}

761 762
static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
				       enum mem_cgroup_events_target target)
763 764 765
{
	unsigned long val, next;

766 767
	val = __this_cpu_read(memcg->stat->events[MEM_CGROUP_EVENTS_COUNT]);
	next = __this_cpu_read(memcg->stat->targets[target]);
768
	/* from time_after() in jiffies.h */
769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784
	if ((long)next - (long)val < 0) {
		switch (target) {
		case MEM_CGROUP_TARGET_THRESH:
			next = val + THRESHOLDS_EVENTS_TARGET;
			break;
		case MEM_CGROUP_TARGET_SOFTLIMIT:
			next = val + SOFTLIMIT_EVENTS_TARGET;
			break;
		case MEM_CGROUP_TARGET_NUMAINFO:
			next = val + NUMAINFO_EVENTS_TARGET;
			break;
		default:
			break;
		}
		__this_cpu_write(memcg->stat->targets[target], next);
		return true;
785
	}
786
	return false;
787 788 789 790 791 792
}

/*
 * Check events in order.
 *
 */
793
static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
794
{
795
	preempt_disable();
796
	/* threshold event is triggered in finer grain than soft limit */
797 798
	if (unlikely(mem_cgroup_event_ratelimit(memcg,
						MEM_CGROUP_TARGET_THRESH))) {
799 800
		bool do_softlimit;
		bool do_numainfo __maybe_unused;
801 802 803 804 805 806 807 808 809

		do_softlimit = mem_cgroup_event_ratelimit(memcg,
						MEM_CGROUP_TARGET_SOFTLIMIT);
#if MAX_NUMNODES > 1
		do_numainfo = mem_cgroup_event_ratelimit(memcg,
						MEM_CGROUP_TARGET_NUMAINFO);
#endif
		preempt_enable();

810
		mem_cgroup_threshold(memcg);
811
		if (unlikely(do_softlimit))
812
			mem_cgroup_update_tree(memcg, page);
813
#if MAX_NUMNODES > 1
814
		if (unlikely(do_numainfo))
815
			atomic_inc(&memcg->numainfo_events);
816
#endif
817 818
	} else
		preempt_enable();
819 820
}

G
Glauber Costa 已提交
821
struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
B
Balbir Singh 已提交
822 823 824 825 826 827
{
	return container_of(cgroup_subsys_state(cont,
				mem_cgroup_subsys_id), struct mem_cgroup,
				css);
}

828
struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
829
{
830 831 832 833 834 835 836 837
	/*
	 * mm_update_next_owner() may clear mm->owner to NULL
	 * if it races with swapoff, page migration, etc.
	 * So this can be called with p == NULL.
	 */
	if (unlikely(!p))
		return NULL;

838 839 840 841
	return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
				struct mem_cgroup, css);
}

842
struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
843
{
844
	struct mem_cgroup *memcg = NULL;
845 846 847

	if (!mm)
		return NULL;
848 849 850 851 852 853 854
	/*
	 * Because we have no locks, mm->owner's may be being moved to other
	 * cgroup. We use css_tryget() here even if this looks
	 * pessimistic (rather than adding locks here).
	 */
	rcu_read_lock();
	do {
855 856
		memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
		if (unlikely(!memcg))
857
			break;
858
	} while (!css_tryget(&memcg->css));
859
	rcu_read_unlock();
860
	return memcg;
861 862
}

863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882
/**
 * mem_cgroup_iter - iterate over memory cgroup hierarchy
 * @root: hierarchy root
 * @prev: previously returned memcg, NULL on first invocation
 * @reclaim: cookie for shared reclaim walks, NULL for full walks
 *
 * Returns references to children of the hierarchy below @root, or
 * @root itself, or %NULL after a full round-trip.
 *
 * Caller must pass the return value in @prev on subsequent
 * invocations for reference counting, or use mem_cgroup_iter_break()
 * to cancel a hierarchy walk before the round-trip is complete.
 *
 * Reclaimers can specify a zone and a priority level in @reclaim to
 * divide up the memcgs in the hierarchy among all concurrent
 * reclaimers operating on the same zone and priority.
 */
struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
				   struct mem_cgroup *prev,
				   struct mem_cgroup_reclaim_cookie *reclaim)
K
KAMEZAWA Hiroyuki 已提交
883
{
884 885
	struct mem_cgroup *memcg = NULL;
	int id = 0;
886

887 888 889
	if (mem_cgroup_disabled())
		return NULL;

890 891
	if (!root)
		root = root_mem_cgroup;
K
KAMEZAWA Hiroyuki 已提交
892

893 894
	if (prev && !reclaim)
		id = css_id(&prev->css);
K
KAMEZAWA Hiroyuki 已提交
895

896 897
	if (prev && prev != root)
		css_put(&prev->css);
K
KAMEZAWA Hiroyuki 已提交
898

899 900 901 902 903
	if (!root->use_hierarchy && root != root_mem_cgroup) {
		if (prev)
			return NULL;
		return root;
	}
K
KAMEZAWA Hiroyuki 已提交
904

905
	while (!memcg) {
906
		struct mem_cgroup_reclaim_iter *uninitialized_var(iter);
907
		struct cgroup_subsys_state *css;
908

909 910 911 912 913 914 915 916 917 918 919
		if (reclaim) {
			int nid = zone_to_nid(reclaim->zone);
			int zid = zone_idx(reclaim->zone);
			struct mem_cgroup_per_zone *mz;

			mz = mem_cgroup_zoneinfo(root, nid, zid);
			iter = &mz->reclaim_iter[reclaim->priority];
			if (prev && reclaim->generation != iter->generation)
				return NULL;
			id = iter->position;
		}
K
KAMEZAWA Hiroyuki 已提交
920

921 922 923 924 925 926 927 928
		rcu_read_lock();
		css = css_get_next(&mem_cgroup_subsys, id + 1, &root->css, &id);
		if (css) {
			if (css == &root->css || css_tryget(css))
				memcg = container_of(css,
						     struct mem_cgroup, css);
		} else
			id = 0;
K
KAMEZAWA Hiroyuki 已提交
929 930
		rcu_read_unlock();

931 932 933 934 935 936 937
		if (reclaim) {
			iter->position = id;
			if (!css)
				iter->generation++;
			else if (!prev && memcg)
				reclaim->generation = iter->generation;
		}
938 939 940 941 942

		if (prev && !css)
			return NULL;
	}
	return memcg;
K
KAMEZAWA Hiroyuki 已提交
943
}
K
KAMEZAWA Hiroyuki 已提交
944

945 946 947 948 949 950 951
/**
 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
 * @root: hierarchy root
 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
 */
void mem_cgroup_iter_break(struct mem_cgroup *root,
			   struct mem_cgroup *prev)
952 953 954 955 956 957
{
	if (!root)
		root = root_mem_cgroup;
	if (prev && prev != root)
		css_put(&prev->css);
}
K
KAMEZAWA Hiroyuki 已提交
958

959 960 961 962 963 964
/*
 * Iteration constructs for visiting all cgroups (under a tree).  If
 * loops are exited prematurely (break), mem_cgroup_iter_break() must
 * be used for reference counting.
 */
#define for_each_mem_cgroup_tree(iter, root)		\
965
	for (iter = mem_cgroup_iter(root, NULL, NULL);	\
966
	     iter != NULL;				\
967
	     iter = mem_cgroup_iter(root, iter, NULL))
968

969
#define for_each_mem_cgroup(iter)			\
970
	for (iter = mem_cgroup_iter(NULL, NULL, NULL);	\
971
	     iter != NULL;				\
972
	     iter = mem_cgroup_iter(NULL, iter, NULL))
K
KAMEZAWA Hiroyuki 已提交
973

974
static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
975
{
976
	return (memcg == root_mem_cgroup);
977 978
}

979 980
void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
{
981
	struct mem_cgroup *memcg;
982 983 984 985 986

	if (!mm)
		return;

	rcu_read_lock();
987 988
	memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
	if (unlikely(!memcg))
989 990 991 992
		goto out;

	switch (idx) {
	case PGFAULT:
993 994 995 996
		this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]);
		break;
	case PGMAJFAULT:
		this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
997 998 999 1000 1001 1002 1003 1004 1005
		break;
	default:
		BUG();
	}
out:
	rcu_read_unlock();
}
EXPORT_SYMBOL(mem_cgroup_count_vm_event);

1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026
/**
 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
 * @zone: zone of the wanted lruvec
 * @mem: memcg of the wanted lruvec
 *
 * Returns the lru list vector holding pages for the given @zone and
 * @mem.  This can be the global zone lruvec, if the memory controller
 * is disabled.
 */
struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
				      struct mem_cgroup *memcg)
{
	struct mem_cgroup_per_zone *mz;

	if (mem_cgroup_disabled())
		return &zone->lruvec;

	mz = mem_cgroup_zoneinfo(memcg, zone_to_nid(zone), zone_idx(zone));
	return &mz->lruvec;
}

K
KAMEZAWA Hiroyuki 已提交
1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039
/*
 * Following LRU functions are allowed to be used without PCG_LOCK.
 * Operations are called by routine of global LRU independently from memcg.
 * What we have to take care of here is validness of pc->mem_cgroup.
 *
 * Changes to pc->mem_cgroup happens when
 * 1. charge
 * 2. moving account
 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
 * It is added to LRU before charge.
 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
 * When moving account, the page is not on LRU. It's isolated.
 */
1040

1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054
/**
 * mem_cgroup_lru_add_list - account for adding an lru page and return lruvec
 * @zone: zone of the page
 * @page: the page
 * @lru: current lru
 *
 * This function accounts for @page being added to @lru, and returns
 * the lruvec for the given @zone and the memcg @page is charged to.
 *
 * The callsite is then responsible for physically linking the page to
 * the returned lruvec->lists[@lru].
 */
struct lruvec *mem_cgroup_lru_add_list(struct zone *zone, struct page *page,
				       enum lru_list lru)
K
KAMEZAWA Hiroyuki 已提交
1055 1056
{
	struct mem_cgroup_per_zone *mz;
1057 1058
	struct mem_cgroup *memcg;
	struct page_cgroup *pc;
1059

1060
	if (mem_cgroup_disabled())
1061 1062
		return &zone->lruvec;

K
KAMEZAWA Hiroyuki 已提交
1063
	pc = lookup_page_cgroup(page);
1064
	memcg = pc->mem_cgroup;
1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077

	/*
	 * Surreptitiously switch any uncharged page to root:
	 * an uncharged page off lru does nothing to secure
	 * its former mem_cgroup from sudden removal.
	 *
	 * Our caller holds lru_lock, and PageCgroupUsed is updated
	 * under page_cgroup lock: between them, they make all uses
	 * of pc->mem_cgroup safe.
	 */
	if (!PageCgroupUsed(pc) && memcg != root_mem_cgroup)
		pc->mem_cgroup = memcg = root_mem_cgroup;

1078 1079 1080 1081
	mz = page_cgroup_zoneinfo(memcg, page);
	/* compound_order() is stabilized through lru_lock */
	MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page);
	return &mz->lruvec;
K
KAMEZAWA Hiroyuki 已提交
1082
}
1083

1084 1085 1086 1087 1088 1089 1090 1091 1092
/**
 * mem_cgroup_lru_del_list - account for removing an lru page
 * @page: the page
 * @lru: target lru
 *
 * This function accounts for @page being removed from @lru.
 *
 * The callsite is then responsible for physically unlinking
 * @page->lru.
1093
 */
1094
void mem_cgroup_lru_del_list(struct page *page, enum lru_list lru)
1095 1096
{
	struct mem_cgroup_per_zone *mz;
1097
	struct mem_cgroup *memcg;
1098 1099 1100 1101 1102 1103
	struct page_cgroup *pc;

	if (mem_cgroup_disabled())
		return;

	pc = lookup_page_cgroup(page);
1104 1105
	memcg = pc->mem_cgroup;
	VM_BUG_ON(!memcg);
1106 1107
	mz = page_cgroup_zoneinfo(memcg, page);
	/* huge page split is done under lru_lock. so, we have no races. */
1108
	VM_BUG_ON(MEM_CGROUP_ZSTAT(mz, lru) < (1 << compound_order(page)));
1109
	MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page);
1110 1111
}

1112
void mem_cgroup_lru_del(struct page *page)
K
KAMEZAWA Hiroyuki 已提交
1113
{
1114
	mem_cgroup_lru_del_list(page, page_lru(page));
1115 1116
}

1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134
/**
 * mem_cgroup_lru_move_lists - account for moving a page between lrus
 * @zone: zone of the page
 * @page: the page
 * @from: current lru
 * @to: target lru
 *
 * This function accounts for @page being moved between the lrus @from
 * and @to, and returns the lruvec for the given @zone and the memcg
 * @page is charged to.
 *
 * The callsite is then responsible for physically relinking
 * @page->lru to the returned lruvec->lists[@to].
 */
struct lruvec *mem_cgroup_lru_move_lists(struct zone *zone,
					 struct page *page,
					 enum lru_list from,
					 enum lru_list to)
1135
{
1136 1137 1138
	/* XXX: Optimize this, especially for @from == @to */
	mem_cgroup_lru_del_list(page, from);
	return mem_cgroup_lru_add_list(zone, page, to);
K
KAMEZAWA Hiroyuki 已提交
1139
}
1140

1141
/*
1142
 * Checks whether given mem is same or in the root_mem_cgroup's
1143 1144
 * hierarchy subtree
 */
1145 1146
static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
		struct mem_cgroup *memcg)
1147
{
1148 1149 1150
	if (root_memcg != memcg) {
		return (root_memcg->use_hierarchy &&
			css_is_ancestor(&memcg->css, &root_memcg->css));
1151 1152 1153 1154 1155
	}

	return true;
}

1156
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg)
1157 1158
{
	int ret;
1159
	struct mem_cgroup *curr = NULL;
1160
	struct task_struct *p;
1161

1162
	p = find_lock_task_mm(task);
1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177
	if (p) {
		curr = try_get_mem_cgroup_from_mm(p->mm);
		task_unlock(p);
	} else {
		/*
		 * All threads may have already detached their mm's, but the oom
		 * killer still needs to detect if they have already been oom
		 * killed to prevent needlessly killing additional tasks.
		 */
		task_lock(task);
		curr = mem_cgroup_from_task(task);
		if (curr)
			css_get(&curr->css);
		task_unlock(task);
	}
1178 1179
	if (!curr)
		return 0;
1180
	/*
1181
	 * We should check use_hierarchy of "memcg" not "curr". Because checking
1182
	 * use_hierarchy of "curr" here make this function true if hierarchy is
1183 1184
	 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
	 * hierarchy(even if use_hierarchy is disabled in "memcg").
1185
	 */
1186
	ret = mem_cgroup_same_or_subtree(memcg, curr);
1187
	css_put(&curr->css);
1188 1189 1190
	return ret;
}

1191
int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg, struct zone *zone)
1192
{
1193 1194 1195
	unsigned long inactive_ratio;
	int nid = zone_to_nid(zone);
	int zid = zone_idx(zone);
1196
	unsigned long inactive;
1197
	unsigned long active;
1198
	unsigned long gb;
1199

1200 1201 1202 1203
	inactive = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid,
						BIT(LRU_INACTIVE_ANON));
	active = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid,
					      BIT(LRU_ACTIVE_ANON));
1204

1205 1206 1207 1208 1209 1210
	gb = (inactive + active) >> (30 - PAGE_SHIFT);
	if (gb)
		inactive_ratio = int_sqrt(10 * gb);
	else
		inactive_ratio = 1;

1211
	return inactive * inactive_ratio < active;
1212 1213
}

1214
int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg, struct zone *zone)
1215 1216 1217
{
	unsigned long active;
	unsigned long inactive;
1218 1219
	int zid = zone_idx(zone);
	int nid = zone_to_nid(zone);
1220

1221 1222 1223 1224
	inactive = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid,
						BIT(LRU_INACTIVE_FILE));
	active = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid,
					      BIT(LRU_ACTIVE_FILE));
1225 1226 1227 1228

	return (active > inactive);
}

K
KOSAKI Motohiro 已提交
1229 1230 1231
struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
						      struct zone *zone)
{
1232
	int nid = zone_to_nid(zone);
K
KOSAKI Motohiro 已提交
1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248
	int zid = zone_idx(zone);
	struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);

	return &mz->reclaim_stat;
}

struct zone_reclaim_stat *
mem_cgroup_get_reclaim_stat_from_page(struct page *page)
{
	struct page_cgroup *pc;
	struct mem_cgroup_per_zone *mz;

	if (mem_cgroup_disabled())
		return NULL;

	pc = lookup_page_cgroup(page);
1249 1250
	if (!PageCgroupUsed(pc))
		return NULL;
1251 1252
	/* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
	smp_rmb();
1253
	mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
K
KOSAKI Motohiro 已提交
1254 1255 1256
	return &mz->reclaim_stat;
}

1257 1258 1259
#define mem_cgroup_from_res_counter(counter, member)	\
	container_of(counter, struct mem_cgroup, member)

1260
/**
1261 1262
 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
 * @mem: the memory cgroup
1263
 *
1264
 * Returns the maximum amount of memory @mem can be charged with, in
1265
 * pages.
1266
 */
1267
static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
1268
{
1269 1270
	unsigned long long margin;

1271
	margin = res_counter_margin(&memcg->res);
1272
	if (do_swap_account)
1273
		margin = min(margin, res_counter_margin(&memcg->memsw));
1274
	return margin >> PAGE_SHIFT;
1275 1276
}

1277
int mem_cgroup_swappiness(struct mem_cgroup *memcg)
K
KOSAKI Motohiro 已提交
1278 1279 1280 1281 1282 1283 1284
{
	struct cgroup *cgrp = memcg->css.cgroup;

	/* root ? */
	if (cgrp->parent == NULL)
		return vm_swappiness;

1285
	return memcg->swappiness;
K
KOSAKI Motohiro 已提交
1286 1287
}

1288
static void mem_cgroup_start_move(struct mem_cgroup *memcg)
1289 1290
{
	int cpu;
1291 1292

	get_online_cpus();
1293
	spin_lock(&memcg->pcp_counter_lock);
1294
	for_each_online_cpu(cpu)
1295 1296 1297
		per_cpu(memcg->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1;
	memcg->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1;
	spin_unlock(&memcg->pcp_counter_lock);
1298
	put_online_cpus();
1299 1300 1301 1302

	synchronize_rcu();
}

1303
static void mem_cgroup_end_move(struct mem_cgroup *memcg)
1304 1305 1306
{
	int cpu;

1307
	if (!memcg)
1308
		return;
1309
	get_online_cpus();
1310
	spin_lock(&memcg->pcp_counter_lock);
1311
	for_each_online_cpu(cpu)
1312 1313 1314
		per_cpu(memcg->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1;
	memcg->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1;
	spin_unlock(&memcg->pcp_counter_lock);
1315
	put_online_cpus();
1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328
}
/*
 * 2 routines for checking "mem" is under move_account() or not.
 *
 * mem_cgroup_stealed() - checking a cgroup is mc.from or not. This is used
 *			  for avoiding race in accounting. If true,
 *			  pc->mem_cgroup may be overwritten.
 *
 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
 *			  under hierarchy of moving cgroups. This is for
 *			  waiting at hith-memory prressure caused by "move".
 */

1329
static bool mem_cgroup_stealed(struct mem_cgroup *memcg)
1330 1331
{
	VM_BUG_ON(!rcu_read_lock_held());
1332
	return this_cpu_read(memcg->stat->count[MEM_CGROUP_ON_MOVE]) > 0;
1333
}
1334

1335
static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
1336
{
1337 1338
	struct mem_cgroup *from;
	struct mem_cgroup *to;
1339
	bool ret = false;
1340 1341 1342 1343 1344 1345 1346 1347 1348
	/*
	 * Unlike task_move routines, we access mc.to, mc.from not under
	 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
	 */
	spin_lock(&mc.lock);
	from = mc.from;
	to = mc.to;
	if (!from)
		goto unlock;
1349

1350 1351
	ret = mem_cgroup_same_or_subtree(memcg, from)
		|| mem_cgroup_same_or_subtree(memcg, to);
1352 1353
unlock:
	spin_unlock(&mc.lock);
1354 1355 1356
	return ret;
}

1357
static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
1358 1359
{
	if (mc.moving_task && current != mc.moving_task) {
1360
		if (mem_cgroup_under_move(memcg)) {
1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372
			DEFINE_WAIT(wait);
			prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
			/* moving charge context might have finished. */
			if (mc.moving_task)
				schedule();
			finish_wait(&mc.waitq, &wait);
			return true;
		}
	}
	return false;
}

1373
/**
1374
 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392
 * @memcg: The memory cgroup that went over limit
 * @p: Task that is going to be killed
 *
 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
 * enabled
 */
void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
{
	struct cgroup *task_cgrp;
	struct cgroup *mem_cgrp;
	/*
	 * Need a buffer in BSS, can't rely on allocations. The code relies
	 * on the assumption that OOM is serialized for memory controller.
	 * If this assumption is broken, revisit this code.
	 */
	static char memcg_name[PATH_MAX];
	int ret;

1393
	if (!memcg || !p)
1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439
		return;


	rcu_read_lock();

	mem_cgrp = memcg->css.cgroup;
	task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);

	ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
	if (ret < 0) {
		/*
		 * Unfortunately, we are unable to convert to a useful name
		 * But we'll still print out the usage information
		 */
		rcu_read_unlock();
		goto done;
	}
	rcu_read_unlock();

	printk(KERN_INFO "Task in %s killed", memcg_name);

	rcu_read_lock();
	ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
	if (ret < 0) {
		rcu_read_unlock();
		goto done;
	}
	rcu_read_unlock();

	/*
	 * Continues from above, so we don't need an KERN_ level
	 */
	printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
done:

	printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
		res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
		res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
		res_counter_read_u64(&memcg->res, RES_FAILCNT));
	printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
		"failcnt %llu\n",
		res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
		res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
		res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
}

1440 1441 1442 1443
/*
 * This function returns the number of memcg under hierarchy tree. Returns
 * 1(self count) if no children.
 */
1444
static int mem_cgroup_count_children(struct mem_cgroup *memcg)
1445 1446
{
	int num = 0;
K
KAMEZAWA Hiroyuki 已提交
1447 1448
	struct mem_cgroup *iter;

1449
	for_each_mem_cgroup_tree(iter, memcg)
K
KAMEZAWA Hiroyuki 已提交
1450
		num++;
1451 1452 1453
	return num;
}

D
David Rientjes 已提交
1454 1455 1456 1457 1458 1459 1460 1461
/*
 * Return the memory (and swap, if configured) limit for a memcg.
 */
u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
{
	u64 limit;
	u64 memsw;

1462 1463 1464
	limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
	limit += total_swap_pages << PAGE_SHIFT;

D
David Rientjes 已提交
1465 1466 1467 1468 1469 1470 1471 1472
	memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
	/*
	 * If memsw is finite and limits the amount of swap space available
	 * to this memcg, return that limit.
	 */
	return min(limit, memsw);
}

1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508
static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg,
					gfp_t gfp_mask,
					unsigned long flags)
{
	unsigned long total = 0;
	bool noswap = false;
	int loop;

	if (flags & MEM_CGROUP_RECLAIM_NOSWAP)
		noswap = true;
	if (!(flags & MEM_CGROUP_RECLAIM_SHRINK) && memcg->memsw_is_minimum)
		noswap = true;

	for (loop = 0; loop < MEM_CGROUP_MAX_RECLAIM_LOOPS; loop++) {
		if (loop)
			drain_all_stock_async(memcg);
		total += try_to_free_mem_cgroup_pages(memcg, gfp_mask, noswap);
		/*
		 * Allow limit shrinkers, which are triggered directly
		 * by userspace, to catch signals and stop reclaim
		 * after minimal progress, regardless of the margin.
		 */
		if (total && (flags & MEM_CGROUP_RECLAIM_SHRINK))
			break;
		if (mem_cgroup_margin(memcg))
			break;
		/*
		 * If nothing was reclaimed after two attempts, there
		 * may be no reclaimable pages in this hierarchy.
		 */
		if (loop && !total)
			break;
	}
	return total;
}

1509 1510 1511 1512 1513 1514 1515 1516 1517 1518
/**
 * test_mem_cgroup_node_reclaimable
 * @mem: the target memcg
 * @nid: the node ID to be checked.
 * @noswap : specify true here if the user wants flle only information.
 *
 * This function returns whether the specified memcg contains any
 * reclaimable pages on a node. Returns true if there are any reclaimable
 * pages in the node.
 */
1519
static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
1520 1521
		int nid, bool noswap)
{
1522
	if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
1523 1524 1525
		return true;
	if (noswap || !total_swap_pages)
		return false;
1526
	if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
1527 1528 1529 1530
		return true;
	return false;

}
1531 1532 1533 1534 1535 1536 1537 1538
#if MAX_NUMNODES > 1

/*
 * Always updating the nodemask is not very good - even if we have an empty
 * list or the wrong list here, we can start from some node and traverse all
 * nodes based on the zonelist. So update the list loosely once per 10 secs.
 *
 */
1539
static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
1540 1541
{
	int nid;
1542 1543 1544 1545
	/*
	 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
	 * pagein/pageout changes since the last update.
	 */
1546
	if (!atomic_read(&memcg->numainfo_events))
1547
		return;
1548
	if (atomic_inc_return(&memcg->numainfo_updating) > 1)
1549 1550 1551
		return;

	/* make a nodemask where this memcg uses memory from */
1552
	memcg->scan_nodes = node_states[N_HIGH_MEMORY];
1553 1554 1555

	for_each_node_mask(nid, node_states[N_HIGH_MEMORY]) {

1556 1557
		if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
			node_clear(nid, memcg->scan_nodes);
1558
	}
1559

1560 1561
	atomic_set(&memcg->numainfo_events, 0);
	atomic_set(&memcg->numainfo_updating, 0);
1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575
}

/*
 * Selecting a node where we start reclaim from. Because what we need is just
 * reducing usage counter, start from anywhere is O,K. Considering
 * memory reclaim from current node, there are pros. and cons.
 *
 * Freeing memory from current node means freeing memory from a node which
 * we'll use or we've used. So, it may make LRU bad. And if several threads
 * hit limits, it will see a contention on a node. But freeing from remote
 * node means more costs for memory reclaim because of memory latency.
 *
 * Now, we use round-robin. Better algorithm is welcomed.
 */
1576
int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1577 1578 1579
{
	int node;

1580 1581
	mem_cgroup_may_update_nodemask(memcg);
	node = memcg->last_scanned_node;
1582

1583
	node = next_node(node, memcg->scan_nodes);
1584
	if (node == MAX_NUMNODES)
1585
		node = first_node(memcg->scan_nodes);
1586 1587 1588 1589 1590 1591 1592 1593 1594
	/*
	 * We call this when we hit limit, not when pages are added to LRU.
	 * No LRU may hold pages because all pages are UNEVICTABLE or
	 * memcg is too small and all pages are not on LRU. In that case,
	 * we use curret node.
	 */
	if (unlikely(node == MAX_NUMNODES))
		node = numa_node_id();

1595
	memcg->last_scanned_node = node;
1596 1597 1598
	return node;
}

1599 1600 1601 1602 1603 1604
/*
 * Check all nodes whether it contains reclaimable pages or not.
 * For quick scan, we make use of scan_nodes. This will allow us to skip
 * unused nodes. But scan_nodes is lazily updated and may not cotain
 * enough new information. We need to do double check.
 */
1605
bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
1606 1607 1608 1609 1610 1611 1612
{
	int nid;

	/*
	 * quick check...making use of scan_node.
	 * We can skip unused nodes.
	 */
1613 1614
	if (!nodes_empty(memcg->scan_nodes)) {
		for (nid = first_node(memcg->scan_nodes);
1615
		     nid < MAX_NUMNODES;
1616
		     nid = next_node(nid, memcg->scan_nodes)) {
1617

1618
			if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
1619 1620 1621 1622 1623 1624 1625
				return true;
		}
	}
	/*
	 * Check rest of nodes.
	 */
	for_each_node_state(nid, N_HIGH_MEMORY) {
1626
		if (node_isset(nid, memcg->scan_nodes))
1627
			continue;
1628
		if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
1629 1630 1631 1632 1633
			return true;
	}
	return false;
}

1634
#else
1635
int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1636 1637 1638
{
	return 0;
}
1639

1640
bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
1641
{
1642
	return test_mem_cgroup_node_reclaimable(memcg, 0, noswap);
1643
}
1644 1645
#endif

1646 1647 1648 1649
static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
				   struct zone *zone,
				   gfp_t gfp_mask,
				   unsigned long *total_scanned)
1650
{
1651
	struct mem_cgroup *victim = NULL;
1652
	int total = 0;
K
KAMEZAWA Hiroyuki 已提交
1653
	int loop = 0;
1654
	unsigned long excess;
1655
	unsigned long nr_scanned;
1656 1657 1658 1659
	struct mem_cgroup_reclaim_cookie reclaim = {
		.zone = zone,
		.priority = 0,
	};
1660

1661
	excess = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT;
K
KAMEZAWA Hiroyuki 已提交
1662

1663
	while (1) {
1664
		victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
1665
		if (!victim) {
K
KAMEZAWA Hiroyuki 已提交
1666
			loop++;
1667 1668 1669 1670 1671 1672
			if (loop >= 2) {
				/*
				 * If we have not been able to reclaim
				 * anything, it might because there are
				 * no reclaimable pages under this hierarchy
				 */
1673
				if (!total)
1674 1675
					break;
				/*
L
Lucas De Marchi 已提交
1676
				 * We want to do more targeted reclaim.
1677 1678 1679 1680 1681
				 * excess >> 2 is not to excessive so as to
				 * reclaim too much, nor too less that we keep
				 * coming back to reclaim from this cgroup
				 */
				if (total >= (excess >> 2) ||
1682
					(loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
1683 1684
					break;
			}
1685
			continue;
1686
		}
1687
		if (!mem_cgroup_reclaimable(victim, false))
1688
			continue;
1689 1690 1691 1692
		total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false,
						     zone, &nr_scanned);
		*total_scanned += nr_scanned;
		if (!res_counter_soft_limit_excess(&root_memcg->res))
1693
			break;
1694
	}
1695
	mem_cgroup_iter_break(root_memcg, victim);
K
KAMEZAWA Hiroyuki 已提交
1696
	return total;
1697 1698
}

K
KAMEZAWA Hiroyuki 已提交
1699 1700 1701
/*
 * Check OOM-Killer is already running under our hierarchy.
 * If someone is running, return false.
1702
 * Has to be called with memcg_oom_lock
K
KAMEZAWA Hiroyuki 已提交
1703
 */
1704
static bool mem_cgroup_oom_lock(struct mem_cgroup *memcg)
K
KAMEZAWA Hiroyuki 已提交
1705
{
1706
	struct mem_cgroup *iter, *failed = NULL;
1707

1708
	for_each_mem_cgroup_tree(iter, memcg) {
1709
		if (iter->oom_lock) {
1710 1711 1712 1713 1714
			/*
			 * this subtree of our hierarchy is already locked
			 * so we cannot give a lock.
			 */
			failed = iter;
1715 1716
			mem_cgroup_iter_break(memcg, iter);
			break;
1717 1718
		} else
			iter->oom_lock = true;
K
KAMEZAWA Hiroyuki 已提交
1719
	}
K
KAMEZAWA Hiroyuki 已提交
1720

1721
	if (!failed)
1722
		return true;
1723 1724 1725 1726 1727

	/*
	 * OK, we failed to lock the whole subtree so we have to clean up
	 * what we set up to the failing subtree
	 */
1728
	for_each_mem_cgroup_tree(iter, memcg) {
1729
		if (iter == failed) {
1730 1731
			mem_cgroup_iter_break(memcg, iter);
			break;
1732 1733 1734
		}
		iter->oom_lock = false;
	}
1735
	return false;
1736
}
1737

1738
/*
1739
 * Has to be called with memcg_oom_lock
1740
 */
1741
static int mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
1742
{
K
KAMEZAWA Hiroyuki 已提交
1743 1744
	struct mem_cgroup *iter;

1745
	for_each_mem_cgroup_tree(iter, memcg)
1746 1747 1748 1749
		iter->oom_lock = false;
	return 0;
}

1750
static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
1751 1752 1753
{
	struct mem_cgroup *iter;

1754
	for_each_mem_cgroup_tree(iter, memcg)
1755 1756 1757
		atomic_inc(&iter->under_oom);
}

1758
static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
1759 1760 1761
{
	struct mem_cgroup *iter;

K
KAMEZAWA Hiroyuki 已提交
1762 1763 1764 1765 1766
	/*
	 * When a new child is created while the hierarchy is under oom,
	 * mem_cgroup_oom_lock() may not be called. We have to use
	 * atomic_add_unless() here.
	 */
1767
	for_each_mem_cgroup_tree(iter, memcg)
1768
		atomic_add_unless(&iter->under_oom, -1, 0);
1769 1770
}

1771
static DEFINE_SPINLOCK(memcg_oom_lock);
K
KAMEZAWA Hiroyuki 已提交
1772 1773
static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);

K
KAMEZAWA Hiroyuki 已提交
1774 1775 1776 1777 1778 1779 1780 1781
struct oom_wait_info {
	struct mem_cgroup *mem;
	wait_queue_t	wait;
};

static int memcg_oom_wake_function(wait_queue_t *wait,
	unsigned mode, int sync, void *arg)
{
1782 1783
	struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg,
			  *oom_wait_memcg;
K
KAMEZAWA Hiroyuki 已提交
1784 1785 1786
	struct oom_wait_info *oom_wait_info;

	oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1787
	oom_wait_memcg = oom_wait_info->mem;
K
KAMEZAWA Hiroyuki 已提交
1788 1789 1790 1791 1792

	/*
	 * Both of oom_wait_info->mem and wake_mem are stable under us.
	 * Then we can use css_is_ancestor without taking care of RCU.
	 */
1793 1794
	if (!mem_cgroup_same_or_subtree(oom_wait_memcg, wake_memcg)
		&& !mem_cgroup_same_or_subtree(wake_memcg, oom_wait_memcg))
K
KAMEZAWA Hiroyuki 已提交
1795 1796 1797 1798
		return 0;
	return autoremove_wake_function(wait, mode, sync, arg);
}

1799
static void memcg_wakeup_oom(struct mem_cgroup *memcg)
K
KAMEZAWA Hiroyuki 已提交
1800
{
1801 1802
	/* for filtering, pass "memcg" as argument. */
	__wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
K
KAMEZAWA Hiroyuki 已提交
1803 1804
}

1805
static void memcg_oom_recover(struct mem_cgroup *memcg)
1806
{
1807 1808
	if (memcg && atomic_read(&memcg->under_oom))
		memcg_wakeup_oom(memcg);
1809 1810
}

K
KAMEZAWA Hiroyuki 已提交
1811 1812 1813
/*
 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
 */
1814
bool mem_cgroup_handle_oom(struct mem_cgroup *memcg, gfp_t mask)
1815
{
K
KAMEZAWA Hiroyuki 已提交
1816
	struct oom_wait_info owait;
1817
	bool locked, need_to_kill;
K
KAMEZAWA Hiroyuki 已提交
1818

1819
	owait.mem = memcg;
K
KAMEZAWA Hiroyuki 已提交
1820 1821 1822 1823
	owait.wait.flags = 0;
	owait.wait.func = memcg_oom_wake_function;
	owait.wait.private = current;
	INIT_LIST_HEAD(&owait.wait.task_list);
1824
	need_to_kill = true;
1825
	mem_cgroup_mark_under_oom(memcg);
1826

1827
	/* At first, try to OOM lock hierarchy under memcg.*/
1828
	spin_lock(&memcg_oom_lock);
1829
	locked = mem_cgroup_oom_lock(memcg);
K
KAMEZAWA Hiroyuki 已提交
1830 1831 1832 1833 1834
	/*
	 * Even if signal_pending(), we can't quit charge() loop without
	 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
	 * under OOM is always welcomed, use TASK_KILLABLE here.
	 */
1835
	prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1836
	if (!locked || memcg->oom_kill_disable)
1837 1838
		need_to_kill = false;
	if (locked)
1839
		mem_cgroup_oom_notify(memcg);
1840
	spin_unlock(&memcg_oom_lock);
K
KAMEZAWA Hiroyuki 已提交
1841

1842 1843
	if (need_to_kill) {
		finish_wait(&memcg_oom_waitq, &owait.wait);
1844
		mem_cgroup_out_of_memory(memcg, mask);
1845
	} else {
K
KAMEZAWA Hiroyuki 已提交
1846
		schedule();
K
KAMEZAWA Hiroyuki 已提交
1847
		finish_wait(&memcg_oom_waitq, &owait.wait);
K
KAMEZAWA Hiroyuki 已提交
1848
	}
1849
	spin_lock(&memcg_oom_lock);
1850
	if (locked)
1851 1852
		mem_cgroup_oom_unlock(memcg);
	memcg_wakeup_oom(memcg);
1853
	spin_unlock(&memcg_oom_lock);
K
KAMEZAWA Hiroyuki 已提交
1854

1855
	mem_cgroup_unmark_under_oom(memcg);
1856

K
KAMEZAWA Hiroyuki 已提交
1857 1858 1859
	if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current))
		return false;
	/* Give chance to dying process */
1860
	schedule_timeout_uninterruptible(1);
K
KAMEZAWA Hiroyuki 已提交
1861
	return true;
1862 1863
}

1864 1865 1866
/*
 * Currently used to update mapped file statistics, but the routine can be
 * generalized to update other statistics as well.
1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885
 *
 * Notes: Race condition
 *
 * We usually use page_cgroup_lock() for accessing page_cgroup member but
 * it tends to be costly. But considering some conditions, we doesn't need
 * to do so _always_.
 *
 * Considering "charge", lock_page_cgroup() is not required because all
 * file-stat operations happen after a page is attached to radix-tree. There
 * are no race with "charge".
 *
 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
 * if there are race with "uncharge". Statistics itself is properly handled
 * by flags.
 *
 * Considering "move", this is an only case we see a race. To make the race
 * small, we check MEM_CGROUP_ON_MOVE percpu value and detect there are
 * possibility of race condition. If there is, we take a lock.
1886
 */
1887

1888 1889
void mem_cgroup_update_page_stat(struct page *page,
				 enum mem_cgroup_page_stat_item idx, int val)
1890
{
1891
	struct mem_cgroup *memcg;
1892 1893
	struct page_cgroup *pc = lookup_page_cgroup(page);
	bool need_unlock = false;
1894
	unsigned long uninitialized_var(flags);
1895

1896
	if (mem_cgroup_disabled())
1897 1898
		return;

1899
	rcu_read_lock();
1900 1901
	memcg = pc->mem_cgroup;
	if (unlikely(!memcg || !PageCgroupUsed(pc)))
1902 1903
		goto out;
	/* pc->mem_cgroup is unstable ? */
1904
	if (unlikely(mem_cgroup_stealed(memcg)) || PageTransHuge(page)) {
1905
		/* take a lock against to access pc->mem_cgroup */
1906
		move_lock_page_cgroup(pc, &flags);
1907
		need_unlock = true;
1908 1909
		memcg = pc->mem_cgroup;
		if (!memcg || !PageCgroupUsed(pc))
1910 1911
			goto out;
	}
1912 1913

	switch (idx) {
1914
	case MEMCG_NR_FILE_MAPPED:
1915 1916 1917
		if (val > 0)
			SetPageCgroupFileMapped(pc);
		else if (!page_mapped(page))
1918
			ClearPageCgroupFileMapped(pc);
1919
		idx = MEM_CGROUP_STAT_FILE_MAPPED;
1920 1921 1922
		break;
	default:
		BUG();
1923
	}
1924

1925
	this_cpu_add(memcg->stat->count[idx], val);
1926

1927 1928
out:
	if (unlikely(need_unlock))
1929
		move_unlock_page_cgroup(pc, &flags);
1930 1931
	rcu_read_unlock();
	return;
1932
}
1933
EXPORT_SYMBOL(mem_cgroup_update_page_stat);
1934

1935 1936 1937 1938
/*
 * size of first charge trial. "32" comes from vmscan.c's magic value.
 * TODO: maybe necessary to use big numbers in big irons.
 */
1939
#define CHARGE_BATCH	32U
1940 1941
struct memcg_stock_pcp {
	struct mem_cgroup *cached; /* this never be root cgroup */
1942
	unsigned int nr_pages;
1943
	struct work_struct work;
1944 1945
	unsigned long flags;
#define FLUSHING_CACHED_CHARGE	(0)
1946 1947
};
static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
1948
static DEFINE_MUTEX(percpu_charge_mutex);
1949 1950

/*
1951
 * Try to consume stocked charge on this cpu. If success, one page is consumed
1952 1953 1954 1955
 * from local stock and true is returned. If the stock is 0 or charges from a
 * cgroup which is not current target, returns false. This stock will be
 * refilled.
 */
1956
static bool consume_stock(struct mem_cgroup *memcg)
1957 1958 1959 1960 1961
{
	struct memcg_stock_pcp *stock;
	bool ret = true;

	stock = &get_cpu_var(memcg_stock);
1962
	if (memcg == stock->cached && stock->nr_pages)
1963
		stock->nr_pages--;
1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976
	else /* need to call res_counter_charge */
		ret = false;
	put_cpu_var(memcg_stock);
	return ret;
}

/*
 * Returns stocks cached in percpu to res_counter and reset cached information.
 */
static void drain_stock(struct memcg_stock_pcp *stock)
{
	struct mem_cgroup *old = stock->cached;

1977 1978 1979 1980
	if (stock->nr_pages) {
		unsigned long bytes = stock->nr_pages * PAGE_SIZE;

		res_counter_uncharge(&old->res, bytes);
1981
		if (do_swap_account)
1982 1983
			res_counter_uncharge(&old->memsw, bytes);
		stock->nr_pages = 0;
1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995
	}
	stock->cached = NULL;
}

/*
 * This must be called under preempt disabled or must be called by
 * a thread which is pinned to local cpu.
 */
static void drain_local_stock(struct work_struct *dummy)
{
	struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock);
	drain_stock(stock);
1996
	clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
1997 1998 1999 2000
}

/*
 * Cache charges(val) which is from res_counter, to local per_cpu area.
2001
 * This will be consumed by consume_stock() function, later.
2002
 */
2003
static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2004 2005 2006
{
	struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);

2007
	if (stock->cached != memcg) { /* reset if necessary */
2008
		drain_stock(stock);
2009
		stock->cached = memcg;
2010
	}
2011
	stock->nr_pages += nr_pages;
2012 2013 2014 2015
	put_cpu_var(memcg_stock);
}

/*
2016
 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2017 2018
 * of the hierarchy under it. sync flag says whether we should block
 * until the work is done.
2019
 */
2020
static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync)
2021
{
2022
	int cpu, curcpu;
2023

2024 2025
	/* Notify other cpus that system-wide "drain" is running */
	get_online_cpus();
2026
	curcpu = get_cpu();
2027 2028
	for_each_online_cpu(cpu) {
		struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2029
		struct mem_cgroup *memcg;
2030

2031 2032
		memcg = stock->cached;
		if (!memcg || !stock->nr_pages)
2033
			continue;
2034
		if (!mem_cgroup_same_or_subtree(root_memcg, memcg))
2035
			continue;
2036 2037 2038 2039 2040 2041
		if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
			if (cpu == curcpu)
				drain_local_stock(&stock->work);
			else
				schedule_work_on(cpu, &stock->work);
		}
2042
	}
2043
	put_cpu();
2044 2045 2046 2047 2048 2049

	if (!sync)
		goto out;

	for_each_online_cpu(cpu) {
		struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2050
		if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
2051 2052 2053
			flush_work(&stock->work);
	}
out:
2054
 	put_online_cpus();
2055 2056 2057 2058 2059 2060 2061 2062
}

/*
 * Tries to drain stocked charges in other cpus. This function is asynchronous
 * and just put a work per cpu for draining localy on each cpu. Caller can
 * expects some charges will be back to res_counter later but cannot wait for
 * it.
 */
2063
static void drain_all_stock_async(struct mem_cgroup *root_memcg)
2064
{
2065 2066 2067 2068 2069
	/*
	 * If someone calls draining, avoid adding more kworker runs.
	 */
	if (!mutex_trylock(&percpu_charge_mutex))
		return;
2070
	drain_all_stock(root_memcg, false);
2071
	mutex_unlock(&percpu_charge_mutex);
2072 2073 2074
}

/* This is a synchronous drain interface. */
2075
static void drain_all_stock_sync(struct mem_cgroup *root_memcg)
2076 2077
{
	/* called when force_empty is called */
2078
	mutex_lock(&percpu_charge_mutex);
2079
	drain_all_stock(root_memcg, true);
2080
	mutex_unlock(&percpu_charge_mutex);
2081 2082
}

2083 2084 2085 2086
/*
 * This function drains percpu counter value from DEAD cpu and
 * move it to local cpu. Note that this function can be preempted.
 */
2087
static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu)
2088 2089 2090
{
	int i;

2091
	spin_lock(&memcg->pcp_counter_lock);
2092
	for (i = 0; i < MEM_CGROUP_STAT_DATA; i++) {
2093
		long x = per_cpu(memcg->stat->count[i], cpu);
2094

2095 2096
		per_cpu(memcg->stat->count[i], cpu) = 0;
		memcg->nocpu_base.count[i] += x;
2097
	}
2098
	for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
2099
		unsigned long x = per_cpu(memcg->stat->events[i], cpu);
2100

2101 2102
		per_cpu(memcg->stat->events[i], cpu) = 0;
		memcg->nocpu_base.events[i] += x;
2103
	}
2104
	/* need to clear ON_MOVE value, works as a kind of lock. */
2105 2106
	per_cpu(memcg->stat->count[MEM_CGROUP_ON_MOVE], cpu) = 0;
	spin_unlock(&memcg->pcp_counter_lock);
2107 2108
}

2109
static void synchronize_mem_cgroup_on_move(struct mem_cgroup *memcg, int cpu)
2110 2111 2112
{
	int idx = MEM_CGROUP_ON_MOVE;

2113 2114 2115
	spin_lock(&memcg->pcp_counter_lock);
	per_cpu(memcg->stat->count[idx], cpu) = memcg->nocpu_base.count[idx];
	spin_unlock(&memcg->pcp_counter_lock);
2116 2117 2118
}

static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
2119 2120 2121 2122 2123
					unsigned long action,
					void *hcpu)
{
	int cpu = (unsigned long)hcpu;
	struct memcg_stock_pcp *stock;
2124
	struct mem_cgroup *iter;
2125

2126
	if ((action == CPU_ONLINE)) {
2127
		for_each_mem_cgroup(iter)
2128 2129 2130 2131
			synchronize_mem_cgroup_on_move(iter, cpu);
		return NOTIFY_OK;
	}

2132
	if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN)
2133
		return NOTIFY_OK;
2134

2135
	for_each_mem_cgroup(iter)
2136 2137
		mem_cgroup_drain_pcp_counter(iter, cpu);

2138 2139 2140 2141 2142
	stock = &per_cpu(memcg_stock, cpu);
	drain_stock(stock);
	return NOTIFY_OK;
}

2143 2144 2145 2146 2147 2148 2149 2150 2151 2152

/* See __mem_cgroup_try_charge() for details */
enum {
	CHARGE_OK,		/* success */
	CHARGE_RETRY,		/* need to retry but retry is not bad */
	CHARGE_NOMEM,		/* we can't do more. return -ENOMEM */
	CHARGE_WOULDBLOCK,	/* GFP_WAIT wasn't set and no enough res. */
	CHARGE_OOM_DIE,		/* the current is killed because of OOM */
};

2153
static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
2154
				unsigned int nr_pages, bool oom_check)
2155
{
2156
	unsigned long csize = nr_pages * PAGE_SIZE;
2157 2158 2159 2160 2161
	struct mem_cgroup *mem_over_limit;
	struct res_counter *fail_res;
	unsigned long flags = 0;
	int ret;

2162
	ret = res_counter_charge(&memcg->res, csize, &fail_res);
2163 2164 2165 2166

	if (likely(!ret)) {
		if (!do_swap_account)
			return CHARGE_OK;
2167
		ret = res_counter_charge(&memcg->memsw, csize, &fail_res);
2168 2169 2170
		if (likely(!ret))
			return CHARGE_OK;

2171
		res_counter_uncharge(&memcg->res, csize);
2172 2173 2174 2175
		mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
		flags |= MEM_CGROUP_RECLAIM_NOSWAP;
	} else
		mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
2176
	/*
2177 2178
	 * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch
	 * of regular pages (CHARGE_BATCH), or a single regular page (1).
2179 2180 2181 2182
	 *
	 * Never reclaim on behalf of optional batching, retry with a
	 * single page instead.
	 */
2183
	if (nr_pages == CHARGE_BATCH)
2184 2185 2186 2187 2188
		return CHARGE_RETRY;

	if (!(gfp_mask & __GFP_WAIT))
		return CHARGE_WOULDBLOCK;

2189
	ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags);
2190
	if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2191
		return CHARGE_RETRY;
2192
	/*
2193 2194 2195 2196 2197 2198 2199
	 * Even though the limit is exceeded at this point, reclaim
	 * may have been able to free some pages.  Retry the charge
	 * before killing the task.
	 *
	 * Only for regular pages, though: huge pages are rather
	 * unlikely to succeed so close to the limit, and we fall back
	 * to regular pages anyway in case of failure.
2200
	 */
2201
	if (nr_pages == 1 && ret)
2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220
		return CHARGE_RETRY;

	/*
	 * At task move, charge accounts can be doubly counted. So, it's
	 * better to wait until the end of task_move if something is going on.
	 */
	if (mem_cgroup_wait_acct_move(mem_over_limit))
		return CHARGE_RETRY;

	/* If we don't need to call oom-killer at el, return immediately */
	if (!oom_check)
		return CHARGE_NOMEM;
	/* check OOM */
	if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask))
		return CHARGE_OOM_DIE;

	return CHARGE_RETRY;
}

2221
/*
2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240
 * __mem_cgroup_try_charge() does
 * 1. detect memcg to be charged against from passed *mm and *ptr,
 * 2. update res_counter
 * 3. call memory reclaim if necessary.
 *
 * In some special case, if the task is fatal, fatal_signal_pending() or
 * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup
 * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon
 * as possible without any hazards. 2: all pages should have a valid
 * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg
 * pointer, that is treated as a charge to root_mem_cgroup.
 *
 * So __mem_cgroup_try_charge() will return
 *  0       ...  on success, filling *ptr with a valid memcg pointer.
 *  -ENOMEM ...  charge failure because of resource limits.
 *  -EINTR  ...  if thread is fatal. *ptr is filled with root_mem_cgroup.
 *
 * Unlike the exported interface, an "oom" parameter is added. if oom==true,
 * the oom-killer can be invoked.
2241
 */
2242
static int __mem_cgroup_try_charge(struct mm_struct *mm,
A
Andrea Arcangeli 已提交
2243
				   gfp_t gfp_mask,
2244
				   unsigned int nr_pages,
2245
				   struct mem_cgroup **ptr,
2246
				   bool oom)
2247
{
2248
	unsigned int batch = max(CHARGE_BATCH, nr_pages);
2249
	int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2250
	struct mem_cgroup *memcg = NULL;
2251
	int ret;
2252

K
KAMEZAWA Hiroyuki 已提交
2253 2254 2255 2256 2257 2258 2259 2260
	/*
	 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
	 * in system level. So, allow to go ahead dying process in addition to
	 * MEMDIE process.
	 */
	if (unlikely(test_thread_flag(TIF_MEMDIE)
		     || fatal_signal_pending(current)))
		goto bypass;
2261

2262
	/*
2263 2264
	 * We always charge the cgroup the mm_struct belongs to.
	 * The mm_struct's mem_cgroup changes on task migration if the
2265 2266 2267
	 * thread group leader migrates. It's possible that mm is not
	 * set, if so charge the init_mm (happens for pagecache usage).
	 */
2268
	if (!*ptr && !mm)
2269
		*ptr = root_mem_cgroup;
K
KAMEZAWA Hiroyuki 已提交
2270
again:
2271 2272 2273 2274
	if (*ptr) { /* css should be a valid one */
		memcg = *ptr;
		VM_BUG_ON(css_is_removed(&memcg->css));
		if (mem_cgroup_is_root(memcg))
K
KAMEZAWA Hiroyuki 已提交
2275
			goto done;
2276
		if (nr_pages == 1 && consume_stock(memcg))
K
KAMEZAWA Hiroyuki 已提交
2277
			goto done;
2278
		css_get(&memcg->css);
2279
	} else {
K
KAMEZAWA Hiroyuki 已提交
2280
		struct task_struct *p;
2281

K
KAMEZAWA Hiroyuki 已提交
2282 2283 2284
		rcu_read_lock();
		p = rcu_dereference(mm->owner);
		/*
2285
		 * Because we don't have task_lock(), "p" can exit.
2286
		 * In that case, "memcg" can point to root or p can be NULL with
2287 2288 2289 2290 2291 2292
		 * race with swapoff. Then, we have small risk of mis-accouning.
		 * But such kind of mis-account by race always happens because
		 * we don't have cgroup_mutex(). It's overkill and we allo that
		 * small race, here.
		 * (*) swapoff at el will charge against mm-struct not against
		 * task-struct. So, mm->owner can be NULL.
K
KAMEZAWA Hiroyuki 已提交
2293
		 */
2294
		memcg = mem_cgroup_from_task(p);
2295 2296 2297
		if (!memcg)
			memcg = root_mem_cgroup;
		if (mem_cgroup_is_root(memcg)) {
K
KAMEZAWA Hiroyuki 已提交
2298 2299 2300
			rcu_read_unlock();
			goto done;
		}
2301
		if (nr_pages == 1 && consume_stock(memcg)) {
K
KAMEZAWA Hiroyuki 已提交
2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313
			/*
			 * It seems dagerous to access memcg without css_get().
			 * But considering how consume_stok works, it's not
			 * necessary. If consume_stock success, some charges
			 * from this memcg are cached on this cpu. So, we
			 * don't need to call css_get()/css_tryget() before
			 * calling consume_stock().
			 */
			rcu_read_unlock();
			goto done;
		}
		/* after here, we may be blocked. we need to get refcnt */
2314
		if (!css_tryget(&memcg->css)) {
K
KAMEZAWA Hiroyuki 已提交
2315 2316 2317 2318 2319
			rcu_read_unlock();
			goto again;
		}
		rcu_read_unlock();
	}
2320

2321 2322
	do {
		bool oom_check;
2323

2324
		/* If killed, bypass charge */
K
KAMEZAWA Hiroyuki 已提交
2325
		if (fatal_signal_pending(current)) {
2326
			css_put(&memcg->css);
2327
			goto bypass;
K
KAMEZAWA Hiroyuki 已提交
2328
		}
2329

2330 2331 2332 2333
		oom_check = false;
		if (oom && !nr_oom_retries) {
			oom_check = true;
			nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2334
		}
2335

2336
		ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, oom_check);
2337 2338 2339 2340
		switch (ret) {
		case CHARGE_OK:
			break;
		case CHARGE_RETRY: /* not in OOM situation but retry */
2341
			batch = nr_pages;
2342 2343
			css_put(&memcg->css);
			memcg = NULL;
K
KAMEZAWA Hiroyuki 已提交
2344
			goto again;
2345
		case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
2346
			css_put(&memcg->css);
2347 2348
			goto nomem;
		case CHARGE_NOMEM: /* OOM routine works */
K
KAMEZAWA Hiroyuki 已提交
2349
			if (!oom) {
2350
				css_put(&memcg->css);
K
KAMEZAWA Hiroyuki 已提交
2351
				goto nomem;
K
KAMEZAWA Hiroyuki 已提交
2352
			}
2353 2354 2355 2356
			/* If oom, we never return -ENOMEM */
			nr_oom_retries--;
			break;
		case CHARGE_OOM_DIE: /* Killed by OOM Killer */
2357
			css_put(&memcg->css);
K
KAMEZAWA Hiroyuki 已提交
2358
			goto bypass;
2359
		}
2360 2361
	} while (ret != CHARGE_OK);

2362
	if (batch > nr_pages)
2363 2364
		refill_stock(memcg, batch - nr_pages);
	css_put(&memcg->css);
2365
done:
2366
	*ptr = memcg;
2367 2368
	return 0;
nomem:
2369
	*ptr = NULL;
2370
	return -ENOMEM;
K
KAMEZAWA Hiroyuki 已提交
2371
bypass:
2372 2373
	*ptr = root_mem_cgroup;
	return -EINTR;
2374
}
2375

2376 2377 2378 2379 2380
/*
 * Somemtimes we have to undo a charge we got by try_charge().
 * This function is for that and do uncharge, put css's refcnt.
 * gotten by try_charge().
 */
2381
static void __mem_cgroup_cancel_charge(struct mem_cgroup *memcg,
2382
				       unsigned int nr_pages)
2383
{
2384
	if (!mem_cgroup_is_root(memcg)) {
2385 2386
		unsigned long bytes = nr_pages * PAGE_SIZE;

2387
		res_counter_uncharge(&memcg->res, bytes);
2388
		if (do_swap_account)
2389
			res_counter_uncharge(&memcg->memsw, bytes);
2390
	}
2391 2392
}

2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411
/*
 * A helper function to get mem_cgroup from ID. must be called under
 * rcu_read_lock(). The caller must check css_is_removed() or some if
 * it's concern. (dropping refcnt from swap can be called against removed
 * memcg.)
 */
static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
{
	struct cgroup_subsys_state *css;

	/* ID 0 is unused ID */
	if (!id)
		return NULL;
	css = css_lookup(&mem_cgroup_subsys, id);
	if (!css)
		return NULL;
	return container_of(css, struct mem_cgroup, css);
}

2412
struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2413
{
2414
	struct mem_cgroup *memcg = NULL;
2415
	struct page_cgroup *pc;
2416
	unsigned short id;
2417 2418
	swp_entry_t ent;

2419 2420 2421
	VM_BUG_ON(!PageLocked(page));

	pc = lookup_page_cgroup(page);
2422
	lock_page_cgroup(pc);
2423
	if (PageCgroupUsed(pc)) {
2424 2425 2426
		memcg = pc->mem_cgroup;
		if (memcg && !css_tryget(&memcg->css))
			memcg = NULL;
2427
	} else if (PageSwapCache(page)) {
2428
		ent.val = page_private(page);
2429
		id = lookup_swap_cgroup_id(ent);
2430
		rcu_read_lock();
2431 2432 2433
		memcg = mem_cgroup_lookup(id);
		if (memcg && !css_tryget(&memcg->css))
			memcg = NULL;
2434
		rcu_read_unlock();
2435
	}
2436
	unlock_page_cgroup(pc);
2437
	return memcg;
2438 2439
}

2440
static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg,
2441
				       struct page *page,
2442
				       unsigned int nr_pages,
2443
				       struct page_cgroup *pc,
2444 2445
				       enum charge_type ctype,
				       bool lrucare)
2446
{
2447 2448 2449
	struct zone *uninitialized_var(zone);
	bool was_on_lru = false;

2450 2451 2452
	lock_page_cgroup(pc);
	if (unlikely(PageCgroupUsed(pc))) {
		unlock_page_cgroup(pc);
2453
		__mem_cgroup_cancel_charge(memcg, nr_pages);
2454 2455 2456 2457 2458 2459
		return;
	}
	/*
	 * we don't need page_cgroup_lock about tail pages, becase they are not
	 * accessed by any other context at this point.
	 */
2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474

	/*
	 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
	 * may already be on some other mem_cgroup's LRU.  Take care of it.
	 */
	if (lrucare) {
		zone = page_zone(page);
		spin_lock_irq(&zone->lru_lock);
		if (PageLRU(page)) {
			ClearPageLRU(page);
			del_page_from_lru_list(zone, page, page_lru(page));
			was_on_lru = true;
		}
	}

2475
	pc->mem_cgroup = memcg;
2476 2477 2478 2479 2480 2481 2482
	/*
	 * We access a page_cgroup asynchronously without lock_page_cgroup().
	 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
	 * is accessed after testing USED bit. To make pc->mem_cgroup visible
	 * before USED bit, we need memory barrier here.
	 * See mem_cgroup_add_lru_list(), etc.
 	 */
K
KAMEZAWA Hiroyuki 已提交
2483
	smp_wmb();
2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496
	switch (ctype) {
	case MEM_CGROUP_CHARGE_TYPE_CACHE:
	case MEM_CGROUP_CHARGE_TYPE_SHMEM:
		SetPageCgroupCache(pc);
		SetPageCgroupUsed(pc);
		break;
	case MEM_CGROUP_CHARGE_TYPE_MAPPED:
		ClearPageCgroupCache(pc);
		SetPageCgroupUsed(pc);
		break;
	default:
		break;
	}
2497

2498 2499 2500 2501 2502 2503 2504 2505 2506
	if (lrucare) {
		if (was_on_lru) {
			VM_BUG_ON(PageLRU(page));
			SetPageLRU(page);
			add_page_to_lru_list(zone, page, page_lru(page));
		}
		spin_unlock_irq(&zone->lru_lock);
	}

2507
	mem_cgroup_charge_statistics(memcg, PageCgroupCache(pc), nr_pages);
2508
	unlock_page_cgroup(pc);
2509

2510 2511 2512 2513 2514
	/*
	 * "charge_statistics" updated event counter. Then, check it.
	 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
	 * if they exceeds softlimit.
	 */
2515
	memcg_check_events(memcg, page);
2516
}
2517

2518 2519 2520
#ifdef CONFIG_TRANSPARENT_HUGEPAGE

#define PCGF_NOCOPY_AT_SPLIT ((1 << PCG_LOCK) | (1 << PCG_MOVE_LOCK) |\
2521
			(1 << PCG_MIGRATION))
2522 2523
/*
 * Because tail pages are not marked as "used", set it. We're under
2524 2525 2526
 * zone->lru_lock, 'splitting on pmd' and compound_lock.
 * charge/uncharge will be never happen and move_account() is done under
 * compound_lock(), so we don't have to take care of races.
2527
 */
2528
void mem_cgroup_split_huge_fixup(struct page *head)
2529 2530
{
	struct page_cgroup *head_pc = lookup_page_cgroup(head);
2531 2532
	struct page_cgroup *pc;
	int i;
2533

2534 2535
	if (mem_cgroup_disabled())
		return;
2536 2537 2538 2539 2540 2541
	for (i = 1; i < HPAGE_PMD_NR; i++) {
		pc = head_pc + i;
		pc->mem_cgroup = head_pc->mem_cgroup;
		smp_wmb();/* see __commit_charge() */
		pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
	}
2542
}
2543
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
2544

2545
/**
2546
 * mem_cgroup_move_account - move account of the page
2547
 * @page: the page
2548
 * @nr_pages: number of regular pages (>1 for huge pages)
2549 2550 2551
 * @pc:	page_cgroup of the page.
 * @from: mem_cgroup which the page is moved from.
 * @to:	mem_cgroup which the page is moved to. @from != @to.
2552
 * @uncharge: whether we should call uncharge and css_put against @from.
2553 2554
 *
 * The caller must confirm following.
K
KAMEZAWA Hiroyuki 已提交
2555
 * - page is not on LRU (isolate_page() is useful.)
2556
 * - compound_lock is held when nr_pages > 1
2557
 *
2558
 * This function doesn't do "charge" nor css_get to new cgroup. It should be
L
Lucas De Marchi 已提交
2559
 * done by a caller(__mem_cgroup_try_charge would be useful). If @uncharge is
2560 2561
 * true, this function does "uncharge" from old cgroup, but it doesn't if
 * @uncharge is false, so a caller should do "uncharge".
2562
 */
2563 2564 2565 2566 2567 2568
static int mem_cgroup_move_account(struct page *page,
				   unsigned int nr_pages,
				   struct page_cgroup *pc,
				   struct mem_cgroup *from,
				   struct mem_cgroup *to,
				   bool uncharge)
2569
{
2570 2571
	unsigned long flags;
	int ret;
2572

2573
	VM_BUG_ON(from == to);
2574
	VM_BUG_ON(PageLRU(page));
2575 2576 2577 2578 2579 2580 2581
	/*
	 * The page is isolated from LRU. So, collapse function
	 * will not handle this page. But page splitting can happen.
	 * Do this check under compound_page_lock(). The caller should
	 * hold it.
	 */
	ret = -EBUSY;
2582
	if (nr_pages > 1 && !PageTransHuge(page))
2583 2584 2585 2586 2587 2588 2589 2590 2591
		goto out;

	lock_page_cgroup(pc);

	ret = -EINVAL;
	if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
		goto unlock;

	move_lock_page_cgroup(pc, &flags);
2592

2593
	if (PageCgroupFileMapped(pc)) {
2594 2595 2596 2597 2598
		/* Update mapped_file data for mem_cgroup */
		preempt_disable();
		__this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
		__this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
		preempt_enable();
2599
	}
2600
	mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages);
2601 2602
	if (uncharge)
		/* This is not "cancel", but cancel_charge does all we need. */
2603
		__mem_cgroup_cancel_charge(from, nr_pages);
2604

2605
	/* caller should have done css_get */
K
KAMEZAWA Hiroyuki 已提交
2606
	pc->mem_cgroup = to;
2607
	mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages);
2608 2609 2610
	/*
	 * We charges against "to" which may not have any tasks. Then, "to"
	 * can be under rmdir(). But in current implementation, caller of
2611
	 * this function is just force_empty() and move charge, so it's
L
Lucas De Marchi 已提交
2612
	 * guaranteed that "to" is never removed. So, we don't check rmdir
2613
	 * status here.
2614
	 */
2615 2616 2617
	move_unlock_page_cgroup(pc, &flags);
	ret = 0;
unlock:
2618
	unlock_page_cgroup(pc);
2619 2620 2621
	/*
	 * check events
	 */
2622 2623
	memcg_check_events(to, page);
	memcg_check_events(from, page);
2624
out:
2625 2626 2627 2628 2629 2630 2631
	return ret;
}

/*
 * move charges to its parent.
 */

2632 2633
static int mem_cgroup_move_parent(struct page *page,
				  struct page_cgroup *pc,
2634 2635 2636 2637 2638 2639
				  struct mem_cgroup *child,
				  gfp_t gfp_mask)
{
	struct cgroup *cg = child->css.cgroup;
	struct cgroup *pcg = cg->parent;
	struct mem_cgroup *parent;
2640
	unsigned int nr_pages;
2641
	unsigned long uninitialized_var(flags);
2642 2643 2644 2645 2646 2647
	int ret;

	/* Is ROOT ? */
	if (!pcg)
		return -EINVAL;

2648 2649 2650 2651 2652
	ret = -EBUSY;
	if (!get_page_unless_zero(page))
		goto out;
	if (isolate_lru_page(page))
		goto put;
2653

2654
	nr_pages = hpage_nr_pages(page);
K
KAMEZAWA Hiroyuki 已提交
2655

2656
	parent = mem_cgroup_from_cont(pcg);
2657
	ret = __mem_cgroup_try_charge(NULL, gfp_mask, nr_pages, &parent, false);
2658
	if (ret)
2659
		goto put_back;
2660

2661
	if (nr_pages > 1)
2662 2663
		flags = compound_lock_irqsave(page);

2664
	ret = mem_cgroup_move_account(page, nr_pages, pc, child, parent, true);
2665
	if (ret)
2666
		__mem_cgroup_cancel_charge(parent, nr_pages);
2667

2668
	if (nr_pages > 1)
2669
		compound_unlock_irqrestore(page, flags);
2670
put_back:
K
KAMEZAWA Hiroyuki 已提交
2671
	putback_lru_page(page);
2672
put:
2673
	put_page(page);
2674
out:
2675 2676 2677
	return ret;
}

2678 2679 2680 2681 2682 2683 2684
/*
 * Charge the memory controller for page usage.
 * Return
 * 0 if the charge was successful
 * < 0 if the cgroup is over its limit
 */
static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
2685
				gfp_t gfp_mask, enum charge_type ctype)
2686
{
2687
	struct mem_cgroup *memcg = NULL;
2688
	unsigned int nr_pages = 1;
2689
	struct page_cgroup *pc;
2690
	bool oom = true;
2691
	int ret;
A
Andrea Arcangeli 已提交
2692

A
Andrea Arcangeli 已提交
2693
	if (PageTransHuge(page)) {
2694
		nr_pages <<= compound_order(page);
A
Andrea Arcangeli 已提交
2695
		VM_BUG_ON(!PageTransHuge(page));
2696 2697 2698 2699 2700
		/*
		 * Never OOM-kill a process for a huge page.  The
		 * fault handler will fall back to regular pages.
		 */
		oom = false;
A
Andrea Arcangeli 已提交
2701
	}
2702 2703

	pc = lookup_page_cgroup(page);
2704
	ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &memcg, oom);
2705
	if (ret == -ENOMEM)
2706
		return ret;
2707
	__mem_cgroup_commit_charge(memcg, page, nr_pages, pc, ctype, false);
2708 2709 2710
	return 0;
}

2711 2712
int mem_cgroup_newpage_charge(struct page *page,
			      struct mm_struct *mm, gfp_t gfp_mask)
2713
{
2714
	if (mem_cgroup_disabled())
2715
		return 0;
2716 2717 2718
	VM_BUG_ON(page_mapped(page));
	VM_BUG_ON(page->mapping && !PageAnon(page));
	VM_BUG_ON(!mm);
2719
	return mem_cgroup_charge_common(page, mm, gfp_mask,
2720
					MEM_CGROUP_CHARGE_TYPE_MAPPED);
2721 2722
}

D
Daisuke Nishimura 已提交
2723 2724 2725 2726
static void
__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
					enum charge_type ctype);

2727 2728
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
				gfp_t gfp_mask)
2729
{
2730
	struct mem_cgroup *memcg = NULL;
2731
	enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
2732 2733
	int ret;

2734
	if (mem_cgroup_disabled())
2735
		return 0;
2736 2737
	if (PageCompound(page))
		return 0;
2738

2739
	if (unlikely(!mm))
2740
		mm = &init_mm;
2741 2742
	if (!page_is_file_cache(page))
		type = MEM_CGROUP_CHARGE_TYPE_SHMEM;
2743

2744
	if (!PageSwapCache(page))
2745
		ret = mem_cgroup_charge_common(page, mm, gfp_mask, type);
2746
	else { /* page is swapcache/shmem */
2747
		ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &memcg);
D
Daisuke Nishimura 已提交
2748
		if (!ret)
2749 2750
			__mem_cgroup_commit_charge_swapin(page, memcg, type);
	}
2751
	return ret;
2752 2753
}

2754 2755 2756
/*
 * While swap-in, try_charge -> commit or cancel, the page is locked.
 * And when try_charge() successfully returns, one refcnt to memcg without
2757
 * struct page_cgroup is acquired. This refcnt will be consumed by
2758 2759
 * "commit()" or removed by "cancel()"
 */
2760 2761
int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
				 struct page *page,
2762
				 gfp_t mask, struct mem_cgroup **memcgp)
2763
{
2764
	struct mem_cgroup *memcg;
2765
	int ret;
2766

2767
	*memcgp = NULL;
2768

2769
	if (mem_cgroup_disabled())
2770 2771 2772 2773 2774 2775
		return 0;

	if (!do_swap_account)
		goto charge_cur_mm;
	/*
	 * A racing thread's fault, or swapoff, may have already updated
H
Hugh Dickins 已提交
2776 2777 2778
	 * the pte, and even removed page from swap cache: in those cases
	 * do_swap_page()'s pte_same() test will fail; but there's also a
	 * KSM case which does need to charge the page.
2779 2780
	 */
	if (!PageSwapCache(page))
H
Hugh Dickins 已提交
2781
		goto charge_cur_mm;
2782 2783
	memcg = try_get_mem_cgroup_from_page(page);
	if (!memcg)
2784
		goto charge_cur_mm;
2785 2786
	*memcgp = memcg;
	ret = __mem_cgroup_try_charge(NULL, mask, 1, memcgp, true);
2787
	css_put(&memcg->css);
2788 2789
	if (ret == -EINTR)
		ret = 0;
2790
	return ret;
2791 2792 2793
charge_cur_mm:
	if (unlikely(!mm))
		mm = &init_mm;
2794 2795 2796 2797
	ret = __mem_cgroup_try_charge(mm, mask, 1, memcgp, true);
	if (ret == -EINTR)
		ret = 0;
	return ret;
2798 2799
}

D
Daisuke Nishimura 已提交
2800
static void
2801
__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg,
D
Daisuke Nishimura 已提交
2802
					enum charge_type ctype)
2803
{
2804 2805
	struct page_cgroup *pc;

2806
	if (mem_cgroup_disabled())
2807
		return;
2808
	if (!memcg)
2809
		return;
2810
	cgroup_exclude_rmdir(&memcg->css);
2811

2812 2813
	pc = lookup_page_cgroup(page);
	__mem_cgroup_commit_charge(memcg, page, 1, pc, ctype, true);
2814 2815 2816
	/*
	 * Now swap is on-memory. This means this page may be
	 * counted both as mem and swap....double count.
2817 2818 2819
	 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
	 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
	 * may call delete_from_swap_cache() before reach here.
2820
	 */
2821
	if (do_swap_account && PageSwapCache(page)) {
2822
		swp_entry_t ent = {.val = page_private(page)};
2823
		struct mem_cgroup *swap_memcg;
2824 2825 2826 2827
		unsigned short id;

		id = swap_cgroup_record(ent, 0);
		rcu_read_lock();
2828 2829
		swap_memcg = mem_cgroup_lookup(id);
		if (swap_memcg) {
2830 2831 2832 2833
			/*
			 * This recorded memcg can be obsolete one. So, avoid
			 * calling css_tryget
			 */
2834 2835 2836 2837 2838
			if (!mem_cgroup_is_root(swap_memcg))
				res_counter_uncharge(&swap_memcg->memsw,
						     PAGE_SIZE);
			mem_cgroup_swap_statistics(swap_memcg, false);
			mem_cgroup_put(swap_memcg);
2839
		}
2840
		rcu_read_unlock();
2841
	}
2842 2843 2844 2845 2846
	/*
	 * At swapin, we may charge account against cgroup which has no tasks.
	 * So, rmdir()->pre_destroy() can be called while we do this charge.
	 * In that case, we need to call pre_destroy() again. check it here.
	 */
2847
	cgroup_release_and_wakeup_rmdir(&memcg->css);
2848 2849
}

2850 2851
void mem_cgroup_commit_charge_swapin(struct page *page,
				     struct mem_cgroup *memcg)
D
Daisuke Nishimura 已提交
2852
{
2853 2854
	__mem_cgroup_commit_charge_swapin(page, memcg,
					  MEM_CGROUP_CHARGE_TYPE_MAPPED);
D
Daisuke Nishimura 已提交
2855 2856
}

2857
void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg)
2858
{
2859
	if (mem_cgroup_disabled())
2860
		return;
2861
	if (!memcg)
2862
		return;
2863
	__mem_cgroup_cancel_charge(memcg, 1);
2864 2865
}

2866
static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg,
2867 2868
				   unsigned int nr_pages,
				   const enum charge_type ctype)
2869 2870 2871
{
	struct memcg_batch_info *batch = NULL;
	bool uncharge_memsw = true;
2872

2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883
	/* If swapout, usage of swap doesn't decrease */
	if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
		uncharge_memsw = false;

	batch = &current->memcg_batch;
	/*
	 * In usual, we do css_get() when we remember memcg pointer.
	 * But in this case, we keep res->usage until end of a series of
	 * uncharges. Then, it's ok to ignore memcg's refcnt.
	 */
	if (!batch->memcg)
2884
		batch->memcg = memcg;
2885 2886
	/*
	 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
L
Lucas De Marchi 已提交
2887
	 * In those cases, all pages freed continuously can be expected to be in
2888 2889 2890 2891 2892 2893 2894 2895
	 * the same cgroup and we have chance to coalesce uncharges.
	 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
	 * because we want to do uncharge as soon as possible.
	 */

	if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
		goto direct_uncharge;

2896
	if (nr_pages > 1)
A
Andrea Arcangeli 已提交
2897 2898
		goto direct_uncharge;

2899 2900 2901 2902 2903
	/*
	 * In typical case, batch->memcg == mem. This means we can
	 * merge a series of uncharges to an uncharge of res_counter.
	 * If not, we uncharge res_counter ony by one.
	 */
2904
	if (batch->memcg != memcg)
2905 2906
		goto direct_uncharge;
	/* remember freed charge and uncharge it later */
2907
	batch->nr_pages++;
2908
	if (uncharge_memsw)
2909
		batch->memsw_nr_pages++;
2910 2911
	return;
direct_uncharge:
2912
	res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE);
2913
	if (uncharge_memsw)
2914 2915 2916
		res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE);
	if (unlikely(batch->memcg != memcg))
		memcg_oom_recover(memcg);
2917 2918
	return;
}
2919

2920
/*
2921
 * uncharge if !page_mapped(page)
2922
 */
2923
static struct mem_cgroup *
2924
__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
2925
{
2926
	struct mem_cgroup *memcg = NULL;
2927 2928
	unsigned int nr_pages = 1;
	struct page_cgroup *pc;
2929

2930
	if (mem_cgroup_disabled())
2931
		return NULL;
2932

K
KAMEZAWA Hiroyuki 已提交
2933
	if (PageSwapCache(page))
2934
		return NULL;
K
KAMEZAWA Hiroyuki 已提交
2935

A
Andrea Arcangeli 已提交
2936
	if (PageTransHuge(page)) {
2937
		nr_pages <<= compound_order(page);
A
Andrea Arcangeli 已提交
2938 2939
		VM_BUG_ON(!PageTransHuge(page));
	}
2940
	/*
2941
	 * Check if our page_cgroup is valid
2942
	 */
2943
	pc = lookup_page_cgroup(page);
2944
	if (unlikely(!PageCgroupUsed(pc)))
2945
		return NULL;
2946

2947
	lock_page_cgroup(pc);
K
KAMEZAWA Hiroyuki 已提交
2948

2949
	memcg = pc->mem_cgroup;
2950

K
KAMEZAWA Hiroyuki 已提交
2951 2952 2953 2954 2955
	if (!PageCgroupUsed(pc))
		goto unlock_out;

	switch (ctype) {
	case MEM_CGROUP_CHARGE_TYPE_MAPPED:
K
KAMEZAWA Hiroyuki 已提交
2956
	case MEM_CGROUP_CHARGE_TYPE_DROP:
2957 2958
		/* See mem_cgroup_prepare_migration() */
		if (page_mapped(page) || PageCgroupMigration(pc))
K
KAMEZAWA Hiroyuki 已提交
2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969
			goto unlock_out;
		break;
	case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
		if (!PageAnon(page)) {	/* Shared memory */
			if (page->mapping && !page_is_file_cache(page))
				goto unlock_out;
		} else if (page_mapped(page)) /* Anon */
				goto unlock_out;
		break;
	default:
		break;
2970
	}
K
KAMEZAWA Hiroyuki 已提交
2971

2972
	mem_cgroup_charge_statistics(memcg, PageCgroupCache(pc), -nr_pages);
K
KAMEZAWA Hiroyuki 已提交
2973

2974
	ClearPageCgroupUsed(pc);
2975 2976 2977 2978 2979 2980
	/*
	 * pc->mem_cgroup is not cleared here. It will be accessed when it's
	 * freed from LRU. This is safe because uncharged page is expected not
	 * to be reused (freed soon). Exception is SwapCache, it's handled by
	 * special functions.
	 */
2981

2982
	unlock_page_cgroup(pc);
K
KAMEZAWA Hiroyuki 已提交
2983
	/*
2984
	 * even after unlock, we have memcg->res.usage here and this memcg
K
KAMEZAWA Hiroyuki 已提交
2985 2986
	 * will never be freed.
	 */
2987
	memcg_check_events(memcg, page);
K
KAMEZAWA Hiroyuki 已提交
2988
	if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
2989 2990
		mem_cgroup_swap_statistics(memcg, true);
		mem_cgroup_get(memcg);
K
KAMEZAWA Hiroyuki 已提交
2991
	}
2992 2993
	if (!mem_cgroup_is_root(memcg))
		mem_cgroup_do_uncharge(memcg, nr_pages, ctype);
2994

2995
	return memcg;
K
KAMEZAWA Hiroyuki 已提交
2996 2997 2998

unlock_out:
	unlock_page_cgroup(pc);
2999
	return NULL;
3000 3001
}

3002 3003
void mem_cgroup_uncharge_page(struct page *page)
{
3004 3005 3006
	/* early check. */
	if (page_mapped(page))
		return;
3007
	VM_BUG_ON(page->mapping && !PageAnon(page));
3008 3009 3010 3011 3012 3013
	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
}

void mem_cgroup_uncharge_cache_page(struct page *page)
{
	VM_BUG_ON(page_mapped(page));
3014
	VM_BUG_ON(page->mapping);
3015 3016 3017
	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
}

3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031
/*
 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
 * In that cases, pages are freed continuously and we can expect pages
 * are in the same memcg. All these calls itself limits the number of
 * pages freed at once, then uncharge_start/end() is called properly.
 * This may be called prural(2) times in a context,
 */

void mem_cgroup_uncharge_start(void)
{
	current->memcg_batch.do_batch++;
	/* We can do nest. */
	if (current->memcg_batch.do_batch == 1) {
		current->memcg_batch.memcg = NULL;
3032 3033
		current->memcg_batch.nr_pages = 0;
		current->memcg_batch.memsw_nr_pages = 0;
3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053
	}
}

void mem_cgroup_uncharge_end(void)
{
	struct memcg_batch_info *batch = &current->memcg_batch;

	if (!batch->do_batch)
		return;

	batch->do_batch--;
	if (batch->do_batch) /* If stacked, do nothing. */
		return;

	if (!batch->memcg)
		return;
	/*
	 * This "batch->memcg" is valid without any css_get/put etc...
	 * bacause we hide charges behind us.
	 */
3054 3055 3056 3057 3058 3059
	if (batch->nr_pages)
		res_counter_uncharge(&batch->memcg->res,
				     batch->nr_pages * PAGE_SIZE);
	if (batch->memsw_nr_pages)
		res_counter_uncharge(&batch->memcg->memsw,
				     batch->memsw_nr_pages * PAGE_SIZE);
3060
	memcg_oom_recover(batch->memcg);
3061 3062 3063 3064
	/* forget this pointer (for sanity check) */
	batch->memcg = NULL;
}

3065
#ifdef CONFIG_SWAP
3066
/*
3067
 * called after __delete_from_swap_cache() and drop "page" account.
3068 3069
 * memcg information is recorded to swap_cgroup of "ent"
 */
K
KAMEZAWA Hiroyuki 已提交
3070 3071
void
mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
3072 3073
{
	struct mem_cgroup *memcg;
K
KAMEZAWA Hiroyuki 已提交
3074 3075 3076 3077 3078 3079
	int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;

	if (!swapout) /* this was a swap cache but the swap is unused ! */
		ctype = MEM_CGROUP_CHARGE_TYPE_DROP;

	memcg = __mem_cgroup_uncharge_common(page, ctype);
3080

K
KAMEZAWA Hiroyuki 已提交
3081 3082 3083 3084 3085
	/*
	 * record memcg information,  if swapout && memcg != NULL,
	 * mem_cgroup_get() was called in uncharge().
	 */
	if (do_swap_account && swapout && memcg)
3086
		swap_cgroup_record(ent, css_id(&memcg->css));
3087
}
3088
#endif
3089 3090 3091 3092 3093 3094 3095

#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
/*
 * called from swap_entry_free(). remove record in swap_cgroup and
 * uncharge "memsw" account.
 */
void mem_cgroup_uncharge_swap(swp_entry_t ent)
K
KAMEZAWA Hiroyuki 已提交
3096
{
3097
	struct mem_cgroup *memcg;
3098
	unsigned short id;
3099 3100 3101 3102

	if (!do_swap_account)
		return;

3103 3104 3105
	id = swap_cgroup_record(ent, 0);
	rcu_read_lock();
	memcg = mem_cgroup_lookup(id);
3106
	if (memcg) {
3107 3108 3109 3110
		/*
		 * We uncharge this because swap is freed.
		 * This memcg can be obsolete one. We avoid calling css_tryget
		 */
3111
		if (!mem_cgroup_is_root(memcg))
3112
			res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
3113
		mem_cgroup_swap_statistics(memcg, false);
3114 3115
		mem_cgroup_put(memcg);
	}
3116
	rcu_read_unlock();
K
KAMEZAWA Hiroyuki 已提交
3117
}
3118 3119 3120 3121 3122 3123

/**
 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
 * @entry: swap entry to be moved
 * @from:  mem_cgroup which the entry is moved from
 * @to:  mem_cgroup which the entry is moved to
3124
 * @need_fixup: whether we should fixup res_counters and refcounts.
3125 3126 3127 3128 3129 3130 3131 3132 3133 3134
 *
 * It succeeds only when the swap_cgroup's record for this entry is the same
 * as the mem_cgroup's id of @from.
 *
 * Returns 0 on success, -EINVAL on failure.
 *
 * The caller must have charged to @to, IOW, called res_counter_charge() about
 * both res and memsw, and called css_get().
 */
static int mem_cgroup_move_swap_account(swp_entry_t entry,
3135
		struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
3136 3137 3138 3139 3140 3141 3142 3143
{
	unsigned short old_id, new_id;

	old_id = css_id(&from->css);
	new_id = css_id(&to->css);

	if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
		mem_cgroup_swap_statistics(from, false);
3144
		mem_cgroup_swap_statistics(to, true);
3145
		/*
3146 3147 3148 3149 3150 3151
		 * This function is only called from task migration context now.
		 * It postpones res_counter and refcount handling till the end
		 * of task migration(mem_cgroup_clear_mc()) for performance
		 * improvement. But we cannot postpone mem_cgroup_get(to)
		 * because if the process that has been moved to @to does
		 * swap-in, the refcount of @to might be decreased to 0.
3152 3153
		 */
		mem_cgroup_get(to);
3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164
		if (need_fixup) {
			if (!mem_cgroup_is_root(from))
				res_counter_uncharge(&from->memsw, PAGE_SIZE);
			mem_cgroup_put(from);
			/*
			 * we charged both to->res and to->memsw, so we should
			 * uncharge to->res.
			 */
			if (!mem_cgroup_is_root(to))
				res_counter_uncharge(&to->res, PAGE_SIZE);
		}
3165 3166 3167 3168 3169 3170
		return 0;
	}
	return -EINVAL;
}
#else
static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
3171
		struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
3172 3173 3174
{
	return -EINVAL;
}
3175
#endif
K
KAMEZAWA Hiroyuki 已提交
3176

3177
/*
3178 3179
 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
 * page belongs to.
3180
 */
3181
int mem_cgroup_prepare_migration(struct page *page,
3182
	struct page *newpage, struct mem_cgroup **memcgp, gfp_t gfp_mask)
3183
{
3184
	struct mem_cgroup *memcg = NULL;
3185
	struct page_cgroup *pc;
3186
	enum charge_type ctype;
3187
	int ret = 0;
3188

3189
	*memcgp = NULL;
3190

A
Andrea Arcangeli 已提交
3191
	VM_BUG_ON(PageTransHuge(page));
3192
	if (mem_cgroup_disabled())
3193 3194
		return 0;

3195 3196 3197
	pc = lookup_page_cgroup(page);
	lock_page_cgroup(pc);
	if (PageCgroupUsed(pc)) {
3198 3199
		memcg = pc->mem_cgroup;
		css_get(&memcg->css);
3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230
		/*
		 * At migrating an anonymous page, its mapcount goes down
		 * to 0 and uncharge() will be called. But, even if it's fully
		 * unmapped, migration may fail and this page has to be
		 * charged again. We set MIGRATION flag here and delay uncharge
		 * until end_migration() is called
		 *
		 * Corner Case Thinking
		 * A)
		 * When the old page was mapped as Anon and it's unmap-and-freed
		 * while migration was ongoing.
		 * If unmap finds the old page, uncharge() of it will be delayed
		 * until end_migration(). If unmap finds a new page, it's
		 * uncharged when it make mapcount to be 1->0. If unmap code
		 * finds swap_migration_entry, the new page will not be mapped
		 * and end_migration() will find it(mapcount==0).
		 *
		 * B)
		 * When the old page was mapped but migraion fails, the kernel
		 * remaps it. A charge for it is kept by MIGRATION flag even
		 * if mapcount goes down to 0. We can do remap successfully
		 * without charging it again.
		 *
		 * C)
		 * The "old" page is under lock_page() until the end of
		 * migration, so, the old page itself will not be swapped-out.
		 * If the new page is swapped out before end_migraton, our
		 * hook to usual swap-out path will catch the event.
		 */
		if (PageAnon(page))
			SetPageCgroupMigration(pc);
3231
	}
3232
	unlock_page_cgroup(pc);
3233 3234 3235 3236
	/*
	 * If the page is not charged at this point,
	 * we return here.
	 */
3237
	if (!memcg)
3238
		return 0;
3239

3240 3241
	*memcgp = memcg;
	ret = __mem_cgroup_try_charge(NULL, gfp_mask, 1, memcgp, false);
3242
	css_put(&memcg->css);/* drop extra refcnt */
3243
	if (ret) {
3244 3245 3246 3247 3248 3249 3250 3251 3252
		if (PageAnon(page)) {
			lock_page_cgroup(pc);
			ClearPageCgroupMigration(pc);
			unlock_page_cgroup(pc);
			/*
			 * The old page may be fully unmapped while we kept it.
			 */
			mem_cgroup_uncharge_page(page);
		}
3253
		/* we'll need to revisit this error code (we have -EINTR) */
3254
		return -ENOMEM;
3255
	}
3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268
	/*
	 * We charge new page before it's used/mapped. So, even if unlock_page()
	 * is called before end_migration, we can catch all events on this new
	 * page. In the case new page is migrated but not remapped, new page's
	 * mapcount will be finally 0 and we call uncharge in end_migration().
	 */
	pc = lookup_page_cgroup(newpage);
	if (PageAnon(page))
		ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
	else if (page_is_file_cache(page))
		ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
	else
		ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
3269
	__mem_cgroup_commit_charge(memcg, newpage, 1, pc, ctype, false);
3270
	return ret;
3271
}
3272

3273
/* remove redundant charge if migration failed*/
3274
void mem_cgroup_end_migration(struct mem_cgroup *memcg,
3275
	struct page *oldpage, struct page *newpage, bool migration_ok)
3276
{
3277
	struct page *used, *unused;
3278 3279
	struct page_cgroup *pc;

3280
	if (!memcg)
3281
		return;
3282
	/* blocks rmdir() */
3283
	cgroup_exclude_rmdir(&memcg->css);
3284
	if (!migration_ok) {
3285 3286
		used = oldpage;
		unused = newpage;
3287
	} else {
3288
		used = newpage;
3289 3290
		unused = oldpage;
	}
3291
	/*
3292 3293 3294
	 * We disallowed uncharge of pages under migration because mapcount
	 * of the page goes down to zero, temporarly.
	 * Clear the flag and check the page should be charged.
3295
	 */
3296 3297 3298 3299
	pc = lookup_page_cgroup(oldpage);
	lock_page_cgroup(pc);
	ClearPageCgroupMigration(pc);
	unlock_page_cgroup(pc);
3300

3301 3302
	__mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);

3303
	/*
3304 3305 3306 3307 3308 3309
	 * If a page is a file cache, radix-tree replacement is very atomic
	 * and we can skip this check. When it was an Anon page, its mapcount
	 * goes down to 0. But because we added MIGRATION flage, it's not
	 * uncharged yet. There are several case but page->mapcount check
	 * and USED bit check in mem_cgroup_uncharge_page() will do enough
	 * check. (see prepare_charge() also)
3310
	 */
3311 3312
	if (PageAnon(used))
		mem_cgroup_uncharge_page(used);
3313
	/*
3314 3315
	 * At migration, we may charge account against cgroup which has no
	 * tasks.
3316 3317 3318
	 * So, rmdir()->pre_destroy() can be called while we do this charge.
	 * In that case, we need to call pre_destroy() again. check it here.
	 */
3319
	cgroup_release_and_wakeup_rmdir(&memcg->css);
3320
}
3321

3322 3323 3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 3349 3350 3351 3352
/*
 * At replace page cache, newpage is not under any memcg but it's on
 * LRU. So, this function doesn't touch res_counter but handles LRU
 * in correct way. Both pages are locked so we cannot race with uncharge.
 */
void mem_cgroup_replace_page_cache(struct page *oldpage,
				  struct page *newpage)
{
	struct mem_cgroup *memcg;
	struct page_cgroup *pc;
	enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;

	if (mem_cgroup_disabled())
		return;

	pc = lookup_page_cgroup(oldpage);
	/* fix accounting on old pages */
	lock_page_cgroup(pc);
	memcg = pc->mem_cgroup;
	mem_cgroup_charge_statistics(memcg, PageCgroupCache(pc), -1);
	ClearPageCgroupUsed(pc);
	unlock_page_cgroup(pc);

	if (PageSwapBacked(oldpage))
		type = MEM_CGROUP_CHARGE_TYPE_SHMEM;

	/*
	 * Even if newpage->mapping was NULL before starting replacement,
	 * the newpage may be on LRU(or pagevec for LRU) already. We lock
	 * LRU while we overwrite pc->mem_cgroup.
	 */
3353
	__mem_cgroup_commit_charge(memcg, newpage, 1, pc, type, true);
3354 3355
}

3356 3357 3358 3359 3360 3361
#ifdef CONFIG_DEBUG_VM
static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
{
	struct page_cgroup *pc;

	pc = lookup_page_cgroup(page);
3362 3363 3364 3365 3366
	/*
	 * Can be NULL while feeding pages into the page allocator for
	 * the first time, i.e. during boot or memory hotplug;
	 * or when mem_cgroup_disabled().
	 */
3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385
	if (likely(pc) && PageCgroupUsed(pc))
		return pc;
	return NULL;
}

bool mem_cgroup_bad_page_check(struct page *page)
{
	if (mem_cgroup_disabled())
		return false;

	return lookup_page_cgroup_used(page) != NULL;
}

void mem_cgroup_print_bad_page(struct page *page)
{
	struct page_cgroup *pc;

	pc = lookup_page_cgroup_used(page);
	if (pc) {
3386
		printk(KERN_ALERT "pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
3387 3388 3389 3390 3391
		       pc, pc->flags, pc->mem_cgroup);
	}
}
#endif

3392 3393
static DEFINE_MUTEX(set_limit_mutex);

3394
static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
3395
				unsigned long long val)
3396
{
3397
	int retry_count;
3398
	u64 memswlimit, memlimit;
3399
	int ret = 0;
3400 3401
	int children = mem_cgroup_count_children(memcg);
	u64 curusage, oldusage;
3402
	int enlarge;
3403 3404 3405 3406 3407 3408 3409 3410 3411

	/*
	 * For keeping hierarchical_reclaim simple, how long we should retry
	 * is depends on callers. We set our retry-count to be function
	 * of # of children which we should visit in this loop.
	 */
	retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;

	oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3412

3413
	enlarge = 0;
3414
	while (retry_count) {
3415 3416 3417 3418
		if (signal_pending(current)) {
			ret = -EINTR;
			break;
		}
3419 3420 3421
		/*
		 * Rather than hide all in some function, I do this in
		 * open coded manner. You see what this really does.
3422
		 * We have to guarantee memcg->res.limit < memcg->memsw.limit.
3423 3424 3425 3426 3427 3428
		 */
		mutex_lock(&set_limit_mutex);
		memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
		if (memswlimit < val) {
			ret = -EINVAL;
			mutex_unlock(&set_limit_mutex);
3429 3430
			break;
		}
3431 3432 3433 3434 3435

		memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
		if (memlimit < val)
			enlarge = 1;

3436
		ret = res_counter_set_limit(&memcg->res, val);
3437 3438 3439 3440 3441 3442
		if (!ret) {
			if (memswlimit == val)
				memcg->memsw_is_minimum = true;
			else
				memcg->memsw_is_minimum = false;
		}
3443 3444 3445 3446 3447
		mutex_unlock(&set_limit_mutex);

		if (!ret)
			break;

3448 3449
		mem_cgroup_reclaim(memcg, GFP_KERNEL,
				   MEM_CGROUP_RECLAIM_SHRINK);
3450 3451 3452 3453 3454 3455
		curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
		/* Usage is reduced ? */
  		if (curusage >= oldusage)
			retry_count--;
		else
			oldusage = curusage;
3456
	}
3457 3458
	if (!ret && enlarge)
		memcg_oom_recover(memcg);
3459

3460 3461 3462
	return ret;
}

L
Li Zefan 已提交
3463 3464
static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
					unsigned long long val)
3465
{
3466
	int retry_count;
3467
	u64 memlimit, memswlimit, oldusage, curusage;
3468 3469
	int children = mem_cgroup_count_children(memcg);
	int ret = -EBUSY;
3470
	int enlarge = 0;
3471

3472 3473 3474
	/* see mem_cgroup_resize_res_limit */
 	retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
	oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3475 3476 3477 3478 3479 3480 3481 3482
	while (retry_count) {
		if (signal_pending(current)) {
			ret = -EINTR;
			break;
		}
		/*
		 * Rather than hide all in some function, I do this in
		 * open coded manner. You see what this really does.
3483
		 * We have to guarantee memcg->res.limit < memcg->memsw.limit.
3484 3485 3486 3487 3488 3489 3490 3491
		 */
		mutex_lock(&set_limit_mutex);
		memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
		if (memlimit > val) {
			ret = -EINVAL;
			mutex_unlock(&set_limit_mutex);
			break;
		}
3492 3493 3494
		memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
		if (memswlimit < val)
			enlarge = 1;
3495
		ret = res_counter_set_limit(&memcg->memsw, val);
3496 3497 3498 3499 3500 3501
		if (!ret) {
			if (memlimit == val)
				memcg->memsw_is_minimum = true;
			else
				memcg->memsw_is_minimum = false;
		}
3502 3503 3504 3505 3506
		mutex_unlock(&set_limit_mutex);

		if (!ret)
			break;

3507 3508 3509
		mem_cgroup_reclaim(memcg, GFP_KERNEL,
				   MEM_CGROUP_RECLAIM_NOSWAP |
				   MEM_CGROUP_RECLAIM_SHRINK);
3510
		curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3511
		/* Usage is reduced ? */
3512
		if (curusage >= oldusage)
3513
			retry_count--;
3514 3515
		else
			oldusage = curusage;
3516
	}
3517 3518
	if (!ret && enlarge)
		memcg_oom_recover(memcg);
3519 3520 3521
	return ret;
}

3522
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3523 3524
					    gfp_t gfp_mask,
					    unsigned long *total_scanned)
3525 3526 3527 3528 3529 3530
{
	unsigned long nr_reclaimed = 0;
	struct mem_cgroup_per_zone *mz, *next_mz = NULL;
	unsigned long reclaimed;
	int loop = 0;
	struct mem_cgroup_tree_per_zone *mctz;
3531
	unsigned long long excess;
3532
	unsigned long nr_scanned;
3533 3534 3535 3536

	if (order > 0)
		return 0;

3537
	mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550
	/*
	 * This loop can run a while, specially if mem_cgroup's continuously
	 * keep exceeding their soft limit and putting the system under
	 * pressure
	 */
	do {
		if (next_mz)
			mz = next_mz;
		else
			mz = mem_cgroup_largest_soft_limit_node(mctz);
		if (!mz)
			break;

3551
		nr_scanned = 0;
3552 3553
		reclaimed = mem_cgroup_soft_reclaim(mz->mem, zone,
						    gfp_mask, &nr_scanned);
3554
		nr_reclaimed += reclaimed;
3555
		*total_scanned += nr_scanned;
3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577
		spin_lock(&mctz->lock);

		/*
		 * If we failed to reclaim anything from this memory cgroup
		 * it is time to move on to the next cgroup
		 */
		next_mz = NULL;
		if (!reclaimed) {
			do {
				/*
				 * Loop until we find yet another one.
				 *
				 * By the time we get the soft_limit lock
				 * again, someone might have aded the
				 * group back on the RB tree. Iterate to
				 * make sure we get a different mem.
				 * mem_cgroup_largest_soft_limit_node returns
				 * NULL if no other cgroup is present on
				 * the tree
				 */
				next_mz =
				__mem_cgroup_largest_soft_limit_node(mctz);
3578
				if (next_mz == mz)
3579
					css_put(&next_mz->mem->css);
3580
				else /* next_mz == NULL or other memcg */
3581 3582 3583 3584
					break;
			} while (1);
		}
		__mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
3585
		excess = res_counter_soft_limit_excess(&mz->mem->res);
3586 3587 3588 3589 3590 3591 3592 3593
		/*
		 * One school of thought says that we should not add
		 * back the node to the tree if reclaim returns 0.
		 * But our reclaim could return 0, simply because due
		 * to priority we are exposing a smaller subset of
		 * memory to reclaim from. Consider this as a longer
		 * term TODO.
		 */
3594 3595
		/* If excess == 0, no tree ops */
		__mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess);
3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613
		spin_unlock(&mctz->lock);
		css_put(&mz->mem->css);
		loop++;
		/*
		 * Could not reclaim anything and there are no more
		 * mem cgroups to try or we seem to be looping without
		 * reclaiming anything.
		 */
		if (!nr_reclaimed &&
			(next_mz == NULL ||
			loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
			break;
	} while (!nr_reclaimed);
	if (next_mz)
		css_put(&next_mz->mem->css);
	return nr_reclaimed;
}

3614 3615 3616 3617
/*
 * This routine traverse page_cgroup in given list and drop them all.
 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
 */
3618
static int mem_cgroup_force_empty_list(struct mem_cgroup *memcg,
K
KAMEZAWA Hiroyuki 已提交
3619
				int node, int zid, enum lru_list lru)
3620
{
K
KAMEZAWA Hiroyuki 已提交
3621 3622
	struct mem_cgroup_per_zone *mz;
	unsigned long flags, loop;
3623
	struct list_head *list;
3624 3625
	struct page *busy;
	struct zone *zone;
3626
	int ret = 0;
3627

K
KAMEZAWA Hiroyuki 已提交
3628
	zone = &NODE_DATA(node)->node_zones[zid];
3629
	mz = mem_cgroup_zoneinfo(memcg, node, zid);
3630
	list = &mz->lruvec.lists[lru];
3631

3632 3633 3634 3635 3636
	loop = MEM_CGROUP_ZSTAT(mz, lru);
	/* give some margin against EBUSY etc...*/
	loop += 256;
	busy = NULL;
	while (loop--) {
3637
		struct page_cgroup *pc;
3638 3639
		struct page *page;

3640
		ret = 0;
K
KAMEZAWA Hiroyuki 已提交
3641
		spin_lock_irqsave(&zone->lru_lock, flags);
3642
		if (list_empty(list)) {
K
KAMEZAWA Hiroyuki 已提交
3643
			spin_unlock_irqrestore(&zone->lru_lock, flags);
3644
			break;
3645
		}
3646 3647 3648
		page = list_entry(list->prev, struct page, lru);
		if (busy == page) {
			list_move(&page->lru, list);
3649
			busy = NULL;
K
KAMEZAWA Hiroyuki 已提交
3650
			spin_unlock_irqrestore(&zone->lru_lock, flags);
3651 3652
			continue;
		}
K
KAMEZAWA Hiroyuki 已提交
3653
		spin_unlock_irqrestore(&zone->lru_lock, flags);
3654

3655
		pc = lookup_page_cgroup(page);
3656

3657
		ret = mem_cgroup_move_parent(page, pc, memcg, GFP_KERNEL);
3658
		if (ret == -ENOMEM || ret == -EINTR)
3659
			break;
3660 3661 3662

		if (ret == -EBUSY || ret == -EINVAL) {
			/* found lock contention or "pc" is obsolete. */
3663
			busy = page;
3664 3665 3666
			cond_resched();
		} else
			busy = NULL;
3667
	}
K
KAMEZAWA Hiroyuki 已提交
3668

3669 3670 3671
	if (!ret && !list_empty(list))
		return -EBUSY;
	return ret;
3672 3673 3674 3675 3676 3677
}

/*
 * make mem_cgroup's charge to be 0 if there is no task.
 * This enables deleting this mem_cgroup.
 */
3678
static int mem_cgroup_force_empty(struct mem_cgroup *memcg, bool free_all)
3679
{
3680 3681 3682
	int ret;
	int node, zid, shrink;
	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3683
	struct cgroup *cgrp = memcg->css.cgroup;
3684

3685
	css_get(&memcg->css);
3686 3687

	shrink = 0;
3688 3689 3690
	/* should free all ? */
	if (free_all)
		goto try_to_free;
3691
move_account:
3692
	do {
3693
		ret = -EBUSY;
3694 3695 3696 3697
		if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
			goto out;
		ret = -EINTR;
		if (signal_pending(current))
3698
			goto out;
3699 3700
		/* This is for making all *used* pages to be on LRU. */
		lru_add_drain_all();
3701
		drain_all_stock_sync(memcg);
3702
		ret = 0;
3703
		mem_cgroup_start_move(memcg);
3704
		for_each_node_state(node, N_HIGH_MEMORY) {
3705
			for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
3706
				enum lru_list l;
3707
				for_each_lru(l) {
3708
					ret = mem_cgroup_force_empty_list(memcg,
K
KAMEZAWA Hiroyuki 已提交
3709
							node, zid, l);
3710 3711 3712
					if (ret)
						break;
				}
3713
			}
3714 3715 3716
			if (ret)
				break;
		}
3717 3718
		mem_cgroup_end_move(memcg);
		memcg_oom_recover(memcg);
3719 3720 3721
		/* it seems parent cgroup doesn't have enough mem */
		if (ret == -ENOMEM)
			goto try_to_free;
3722
		cond_resched();
3723
	/* "ret" should also be checked to ensure all lists are empty. */
3724
	} while (memcg->res.usage > 0 || ret);
3725
out:
3726
	css_put(&memcg->css);
3727
	return ret;
3728 3729

try_to_free:
3730 3731
	/* returns EBUSY if there is a task or if we come here twice. */
	if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
3732 3733 3734
		ret = -EBUSY;
		goto out;
	}
3735 3736
	/* we call try-to-free pages for make this cgroup empty */
	lru_add_drain_all();
3737 3738
	/* try to free all pages in this cgroup */
	shrink = 1;
3739
	while (nr_retries && memcg->res.usage > 0) {
3740
		int progress;
3741 3742 3743 3744 3745

		if (signal_pending(current)) {
			ret = -EINTR;
			goto out;
		}
3746
		progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL,
3747
						false);
3748
		if (!progress) {
3749
			nr_retries--;
3750
			/* maybe some writeback is necessary */
3751
			congestion_wait(BLK_RW_ASYNC, HZ/10);
3752
		}
3753 3754

	}
K
KAMEZAWA Hiroyuki 已提交
3755
	lru_add_drain();
3756
	/* try move_account...there may be some *locked* pages. */
3757
	goto move_account;
3758 3759
}

3760 3761 3762 3763 3764 3765
int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
{
	return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
}


3766 3767 3768 3769 3770 3771 3772 3773 3774
static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
{
	return mem_cgroup_from_cont(cont)->use_hierarchy;
}

static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
					u64 val)
{
	int retval = 0;
3775
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3776
	struct cgroup *parent = cont->parent;
3777
	struct mem_cgroup *parent_memcg = NULL;
3778 3779

	if (parent)
3780
		parent_memcg = mem_cgroup_from_cont(parent);
3781 3782 3783

	cgroup_lock();
	/*
3784
	 * If parent's use_hierarchy is set, we can't make any modifications
3785 3786 3787 3788 3789 3790
	 * in the child subtrees. If it is unset, then the change can
	 * occur, provided the current cgroup has no children.
	 *
	 * For the root cgroup, parent_mem is NULL, we allow value to be
	 * set if there are no children.
	 */
3791
	if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
3792 3793
				(val == 1 || val == 0)) {
		if (list_empty(&cont->children))
3794
			memcg->use_hierarchy = val;
3795 3796 3797 3798 3799 3800 3801 3802 3803
		else
			retval = -EBUSY;
	} else
		retval = -EINVAL;
	cgroup_unlock();

	return retval;
}

3804

3805
static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *memcg,
3806
					       enum mem_cgroup_stat_index idx)
3807
{
K
KAMEZAWA Hiroyuki 已提交
3808
	struct mem_cgroup *iter;
3809
	long val = 0;
3810

3811
	/* Per-cpu values can be negative, use a signed accumulator */
3812
	for_each_mem_cgroup_tree(iter, memcg)
K
KAMEZAWA Hiroyuki 已提交
3813 3814 3815 3816 3817
		val += mem_cgroup_read_stat(iter, idx);

	if (val < 0) /* race ? */
		val = 0;
	return val;
3818 3819
}

3820
static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
3821
{
K
KAMEZAWA Hiroyuki 已提交
3822
	u64 val;
3823

3824
	if (!mem_cgroup_is_root(memcg)) {
3825
		if (!swap)
3826
			return res_counter_read_u64(&memcg->res, RES_USAGE);
3827
		else
3828
			return res_counter_read_u64(&memcg->memsw, RES_USAGE);
3829 3830
	}

3831 3832
	val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE);
	val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS);
3833

K
KAMEZAWA Hiroyuki 已提交
3834
	if (swap)
3835
		val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAPOUT);
3836 3837 3838 3839

	return val << PAGE_SHIFT;
}

3840
static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
B
Balbir Singh 已提交
3841
{
3842
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3843
	u64 val;
3844 3845 3846 3847 3848 3849
	int type, name;

	type = MEMFILE_TYPE(cft->private);
	name = MEMFILE_ATTR(cft->private);
	switch (type) {
	case _MEM:
3850
		if (name == RES_USAGE)
3851
			val = mem_cgroup_usage(memcg, false);
3852
		else
3853
			val = res_counter_read_u64(&memcg->res, name);
3854 3855
		break;
	case _MEMSWAP:
3856
		if (name == RES_USAGE)
3857
			val = mem_cgroup_usage(memcg, true);
3858
		else
3859
			val = res_counter_read_u64(&memcg->memsw, name);
3860 3861 3862 3863 3864 3865
		break;
	default:
		BUG();
		break;
	}
	return val;
B
Balbir Singh 已提交
3866
}
3867 3868 3869 3870
/*
 * The user of this function is...
 * RES_LIMIT.
 */
3871 3872
static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
			    const char *buffer)
B
Balbir Singh 已提交
3873
{
3874
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3875
	int type, name;
3876 3877 3878
	unsigned long long val;
	int ret;

3879 3880 3881
	type = MEMFILE_TYPE(cft->private);
	name = MEMFILE_ATTR(cft->private);
	switch (name) {
3882
	case RES_LIMIT:
3883 3884 3885 3886
		if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
			ret = -EINVAL;
			break;
		}
3887 3888
		/* This function does all necessary parse...reuse it */
		ret = res_counter_memparse_write_strategy(buffer, &val);
3889 3890 3891
		if (ret)
			break;
		if (type == _MEM)
3892
			ret = mem_cgroup_resize_limit(memcg, val);
3893 3894
		else
			ret = mem_cgroup_resize_memsw_limit(memcg, val);
3895
		break;
3896 3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907 3908 3909
	case RES_SOFT_LIMIT:
		ret = res_counter_memparse_write_strategy(buffer, &val);
		if (ret)
			break;
		/*
		 * For memsw, soft limits are hard to implement in terms
		 * of semantics, for now, we support soft limits for
		 * control without swap
		 */
		if (type == _MEM)
			ret = res_counter_set_soft_limit(&memcg->res, val);
		else
			ret = -EINVAL;
		break;
3910 3911 3912 3913 3914
	default:
		ret = -EINVAL; /* should be BUG() ? */
		break;
	}
	return ret;
B
Balbir Singh 已提交
3915 3916
}

3917 3918 3919 3920 3921 3922 3923 3924 3925 3926 3927 3928 3929 3930 3931 3932 3933 3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944
static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
		unsigned long long *mem_limit, unsigned long long *memsw_limit)
{
	struct cgroup *cgroup;
	unsigned long long min_limit, min_memsw_limit, tmp;

	min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
	min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
	cgroup = memcg->css.cgroup;
	if (!memcg->use_hierarchy)
		goto out;

	while (cgroup->parent) {
		cgroup = cgroup->parent;
		memcg = mem_cgroup_from_cont(cgroup);
		if (!memcg->use_hierarchy)
			break;
		tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
		min_limit = min(min_limit, tmp);
		tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
		min_memsw_limit = min(min_memsw_limit, tmp);
	}
out:
	*mem_limit = min_limit;
	*memsw_limit = min_memsw_limit;
	return;
}

3945
static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
3946
{
3947
	struct mem_cgroup *memcg;
3948
	int type, name;
3949

3950
	memcg = mem_cgroup_from_cont(cont);
3951 3952 3953
	type = MEMFILE_TYPE(event);
	name = MEMFILE_ATTR(event);
	switch (name) {
3954
	case RES_MAX_USAGE:
3955
		if (type == _MEM)
3956
			res_counter_reset_max(&memcg->res);
3957
		else
3958
			res_counter_reset_max(&memcg->memsw);
3959 3960
		break;
	case RES_FAILCNT:
3961
		if (type == _MEM)
3962
			res_counter_reset_failcnt(&memcg->res);
3963
		else
3964
			res_counter_reset_failcnt(&memcg->memsw);
3965 3966
		break;
	}
3967

3968
	return 0;
3969 3970
}

3971 3972 3973 3974 3975 3976
static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
					struct cftype *cft)
{
	return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
}

3977
#ifdef CONFIG_MMU
3978 3979 3980
static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
					struct cftype *cft, u64 val)
{
3981
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3982 3983 3984 3985 3986 3987 3988 3989 3990

	if (val >= (1 << NR_MOVE_TYPE))
		return -EINVAL;
	/*
	 * We check this value several times in both in can_attach() and
	 * attach(), so we need cgroup lock to prevent this value from being
	 * inconsistent.
	 */
	cgroup_lock();
3991
	memcg->move_charge_at_immigrate = val;
3992 3993 3994 3995
	cgroup_unlock();

	return 0;
}
3996 3997 3998 3999 4000 4001 4002
#else
static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
					struct cftype *cft, u64 val)
{
	return -ENOSYS;
}
#endif
4003

K
KAMEZAWA Hiroyuki 已提交
4004 4005 4006 4007 4008

/* For read statistics */
enum {
	MCS_CACHE,
	MCS_RSS,
4009
	MCS_FILE_MAPPED,
K
KAMEZAWA Hiroyuki 已提交
4010 4011
	MCS_PGPGIN,
	MCS_PGPGOUT,
4012
	MCS_SWAP,
4013 4014
	MCS_PGFAULT,
	MCS_PGMAJFAULT,
K
KAMEZAWA Hiroyuki 已提交
4015 4016 4017 4018 4019 4020 4021 4022 4023 4024
	MCS_INACTIVE_ANON,
	MCS_ACTIVE_ANON,
	MCS_INACTIVE_FILE,
	MCS_ACTIVE_FILE,
	MCS_UNEVICTABLE,
	NR_MCS_STAT,
};

struct mcs_total_stat {
	s64 stat[NR_MCS_STAT];
4025 4026
};

K
KAMEZAWA Hiroyuki 已提交
4027 4028 4029 4030 4031 4032
struct {
	char *local_name;
	char *total_name;
} memcg_stat_strings[NR_MCS_STAT] = {
	{"cache", "total_cache"},
	{"rss", "total_rss"},
4033
	{"mapped_file", "total_mapped_file"},
K
KAMEZAWA Hiroyuki 已提交
4034 4035
	{"pgpgin", "total_pgpgin"},
	{"pgpgout", "total_pgpgout"},
4036
	{"swap", "total_swap"},
4037 4038
	{"pgfault", "total_pgfault"},
	{"pgmajfault", "total_pgmajfault"},
K
KAMEZAWA Hiroyuki 已提交
4039 4040 4041 4042 4043 4044 4045 4046
	{"inactive_anon", "total_inactive_anon"},
	{"active_anon", "total_active_anon"},
	{"inactive_file", "total_inactive_file"},
	{"active_file", "total_active_file"},
	{"unevictable", "total_unevictable"}
};


K
KAMEZAWA Hiroyuki 已提交
4047
static void
4048
mem_cgroup_get_local_stat(struct mem_cgroup *memcg, struct mcs_total_stat *s)
K
KAMEZAWA Hiroyuki 已提交
4049 4050 4051 4052
{
	s64 val;

	/* per cpu stat */
4053
	val = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_CACHE);
K
KAMEZAWA Hiroyuki 已提交
4054
	s->stat[MCS_CACHE] += val * PAGE_SIZE;
4055
	val = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_RSS);
K
KAMEZAWA Hiroyuki 已提交
4056
	s->stat[MCS_RSS] += val * PAGE_SIZE;
4057
	val = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_FILE_MAPPED);
4058
	s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
4059
	val = mem_cgroup_read_events(memcg, MEM_CGROUP_EVENTS_PGPGIN);
K
KAMEZAWA Hiroyuki 已提交
4060
	s->stat[MCS_PGPGIN] += val;
4061
	val = mem_cgroup_read_events(memcg, MEM_CGROUP_EVENTS_PGPGOUT);
K
KAMEZAWA Hiroyuki 已提交
4062
	s->stat[MCS_PGPGOUT] += val;
4063
	if (do_swap_account) {
4064
		val = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_SWAPOUT);
4065 4066
		s->stat[MCS_SWAP] += val * PAGE_SIZE;
	}
4067
	val = mem_cgroup_read_events(memcg, MEM_CGROUP_EVENTS_PGFAULT);
4068
	s->stat[MCS_PGFAULT] += val;
4069
	val = mem_cgroup_read_events(memcg, MEM_CGROUP_EVENTS_PGMAJFAULT);
4070
	s->stat[MCS_PGMAJFAULT] += val;
K
KAMEZAWA Hiroyuki 已提交
4071 4072

	/* per zone stat */
4073
	val = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_INACTIVE_ANON));
K
KAMEZAWA Hiroyuki 已提交
4074
	s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
4075
	val = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_ACTIVE_ANON));
K
KAMEZAWA Hiroyuki 已提交
4076
	s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE;
4077
	val = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_INACTIVE_FILE));
K
KAMEZAWA Hiroyuki 已提交
4078
	s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE;
4079
	val = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_ACTIVE_FILE));
K
KAMEZAWA Hiroyuki 已提交
4080
	s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE;
4081
	val = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_UNEVICTABLE));
K
KAMEZAWA Hiroyuki 已提交
4082 4083 4084 4085
	s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE;
}

static void
4086
mem_cgroup_get_total_stat(struct mem_cgroup *memcg, struct mcs_total_stat *s)
K
KAMEZAWA Hiroyuki 已提交
4087
{
K
KAMEZAWA Hiroyuki 已提交
4088 4089
	struct mem_cgroup *iter;

4090
	for_each_mem_cgroup_tree(iter, memcg)
K
KAMEZAWA Hiroyuki 已提交
4091
		mem_cgroup_get_local_stat(iter, s);
K
KAMEZAWA Hiroyuki 已提交
4092 4093
}

4094 4095 4096 4097 4098 4099 4100 4101 4102
#ifdef CONFIG_NUMA
static int mem_control_numa_stat_show(struct seq_file *m, void *arg)
{
	int nid;
	unsigned long total_nr, file_nr, anon_nr, unevictable_nr;
	unsigned long node_nr;
	struct cgroup *cont = m->private;
	struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);

4103
	total_nr = mem_cgroup_nr_lru_pages(mem_cont, LRU_ALL);
4104 4105
	seq_printf(m, "total=%lu", total_nr);
	for_each_node_state(nid, N_HIGH_MEMORY) {
4106
		node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid, LRU_ALL);
4107 4108 4109 4110
		seq_printf(m, " N%d=%lu", nid, node_nr);
	}
	seq_putc(m, '\n');

4111
	file_nr = mem_cgroup_nr_lru_pages(mem_cont, LRU_ALL_FILE);
4112 4113
	seq_printf(m, "file=%lu", file_nr);
	for_each_node_state(nid, N_HIGH_MEMORY) {
4114 4115
		node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid,
				LRU_ALL_FILE);
4116 4117 4118 4119
		seq_printf(m, " N%d=%lu", nid, node_nr);
	}
	seq_putc(m, '\n');

4120
	anon_nr = mem_cgroup_nr_lru_pages(mem_cont, LRU_ALL_ANON);
4121 4122
	seq_printf(m, "anon=%lu", anon_nr);
	for_each_node_state(nid, N_HIGH_MEMORY) {
4123 4124
		node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid,
				LRU_ALL_ANON);
4125 4126 4127 4128
		seq_printf(m, " N%d=%lu", nid, node_nr);
	}
	seq_putc(m, '\n');

4129
	unevictable_nr = mem_cgroup_nr_lru_pages(mem_cont, BIT(LRU_UNEVICTABLE));
4130 4131
	seq_printf(m, "unevictable=%lu", unevictable_nr);
	for_each_node_state(nid, N_HIGH_MEMORY) {
4132 4133
		node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid,
				BIT(LRU_UNEVICTABLE));
4134 4135 4136 4137 4138 4139 4140
		seq_printf(m, " N%d=%lu", nid, node_nr);
	}
	seq_putc(m, '\n');
	return 0;
}
#endif /* CONFIG_NUMA */

4141 4142
static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
				 struct cgroup_map_cb *cb)
4143 4144
{
	struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
K
KAMEZAWA Hiroyuki 已提交
4145
	struct mcs_total_stat mystat;
4146 4147
	int i;

K
KAMEZAWA Hiroyuki 已提交
4148 4149
	memset(&mystat, 0, sizeof(mystat));
	mem_cgroup_get_local_stat(mem_cont, &mystat);
4150

4151

4152 4153 4154
	for (i = 0; i < NR_MCS_STAT; i++) {
		if (i == MCS_SWAP && !do_swap_account)
			continue;
K
KAMEZAWA Hiroyuki 已提交
4155
		cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
4156
	}
L
Lee Schermerhorn 已提交
4157

K
KAMEZAWA Hiroyuki 已提交
4158
	/* Hierarchical information */
4159 4160 4161 4162 4163 4164 4165
	{
		unsigned long long limit, memsw_limit;
		memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
		cb->fill(cb, "hierarchical_memory_limit", limit);
		if (do_swap_account)
			cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
	}
K
KOSAKI Motohiro 已提交
4166

K
KAMEZAWA Hiroyuki 已提交
4167 4168
	memset(&mystat, 0, sizeof(mystat));
	mem_cgroup_get_total_stat(mem_cont, &mystat);
4169 4170 4171
	for (i = 0; i < NR_MCS_STAT; i++) {
		if (i == MCS_SWAP && !do_swap_account)
			continue;
K
KAMEZAWA Hiroyuki 已提交
4172
		cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
4173
	}
K
KAMEZAWA Hiroyuki 已提交
4174

K
KOSAKI Motohiro 已提交
4175 4176 4177 4178 4179 4180 4181 4182 4183 4184 4185 4186 4187 4188 4189 4190 4191 4192 4193 4194 4195 4196 4197 4198 4199 4200 4201
#ifdef CONFIG_DEBUG_VM
	{
		int nid, zid;
		struct mem_cgroup_per_zone *mz;
		unsigned long recent_rotated[2] = {0, 0};
		unsigned long recent_scanned[2] = {0, 0};

		for_each_online_node(nid)
			for (zid = 0; zid < MAX_NR_ZONES; zid++) {
				mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);

				recent_rotated[0] +=
					mz->reclaim_stat.recent_rotated[0];
				recent_rotated[1] +=
					mz->reclaim_stat.recent_rotated[1];
				recent_scanned[0] +=
					mz->reclaim_stat.recent_scanned[0];
				recent_scanned[1] +=
					mz->reclaim_stat.recent_scanned[1];
			}
		cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
		cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
		cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
		cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
	}
#endif

4202 4203 4204
	return 0;
}

K
KOSAKI Motohiro 已提交
4205 4206 4207 4208
static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);

4209
	return mem_cgroup_swappiness(memcg);
K
KOSAKI Motohiro 已提交
4210 4211 4212 4213 4214 4215 4216
}

static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
				       u64 val)
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
	struct mem_cgroup *parent;
4217

K
KOSAKI Motohiro 已提交
4218 4219 4220 4221 4222 4223 4224
	if (val > 100)
		return -EINVAL;

	if (cgrp->parent == NULL)
		return -EINVAL;

	parent = mem_cgroup_from_cont(cgrp->parent);
4225 4226 4227

	cgroup_lock();

K
KOSAKI Motohiro 已提交
4228 4229
	/* If under hierarchy, only empty-root can set this value */
	if ((parent->use_hierarchy) ||
4230 4231
	    (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
		cgroup_unlock();
K
KOSAKI Motohiro 已提交
4232
		return -EINVAL;
4233
	}
K
KOSAKI Motohiro 已提交
4234 4235 4236

	memcg->swappiness = val;

4237 4238
	cgroup_unlock();

K
KOSAKI Motohiro 已提交
4239 4240 4241
	return 0;
}

4242 4243 4244 4245 4246 4247 4248 4249
static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
{
	struct mem_cgroup_threshold_ary *t;
	u64 usage;
	int i;

	rcu_read_lock();
	if (!swap)
4250
		t = rcu_dereference(memcg->thresholds.primary);
4251
	else
4252
		t = rcu_dereference(memcg->memsw_thresholds.primary);
4253 4254 4255 4256 4257 4258 4259 4260 4261 4262 4263

	if (!t)
		goto unlock;

	usage = mem_cgroup_usage(memcg, swap);

	/*
	 * current_threshold points to threshold just below usage.
	 * If it's not true, a threshold was crossed after last
	 * call of __mem_cgroup_threshold().
	 */
4264
	i = t->current_threshold;
4265 4266 4267 4268 4269 4270 4271 4272 4273 4274 4275 4276 4277 4278 4279 4280 4281 4282 4283 4284 4285 4286 4287

	/*
	 * Iterate backward over array of thresholds starting from
	 * current_threshold and check if a threshold is crossed.
	 * If none of thresholds below usage is crossed, we read
	 * only one element of the array here.
	 */
	for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
		eventfd_signal(t->entries[i].eventfd, 1);

	/* i = current_threshold + 1 */
	i++;

	/*
	 * Iterate forward over array of thresholds starting from
	 * current_threshold+1 and check if a threshold is crossed.
	 * If none of thresholds above usage is crossed, we read
	 * only one element of the array here.
	 */
	for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
		eventfd_signal(t->entries[i].eventfd, 1);

	/* Update current_threshold */
4288
	t->current_threshold = i - 1;
4289 4290 4291 4292 4293 4294
unlock:
	rcu_read_unlock();
}

static void mem_cgroup_threshold(struct mem_cgroup *memcg)
{
4295 4296 4297 4298 4299 4300 4301
	while (memcg) {
		__mem_cgroup_threshold(memcg, false);
		if (do_swap_account)
			__mem_cgroup_threshold(memcg, true);

		memcg = parent_mem_cgroup(memcg);
	}
4302 4303 4304 4305 4306 4307 4308 4309 4310 4311
}

static int compare_thresholds(const void *a, const void *b)
{
	const struct mem_cgroup_threshold *_a = a;
	const struct mem_cgroup_threshold *_b = b;

	return _a->threshold - _b->threshold;
}

4312
static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
K
KAMEZAWA Hiroyuki 已提交
4313 4314 4315
{
	struct mem_cgroup_eventfd_list *ev;

4316
	list_for_each_entry(ev, &memcg->oom_notify, list)
K
KAMEZAWA Hiroyuki 已提交
4317 4318 4319 4320
		eventfd_signal(ev->eventfd, 1);
	return 0;
}

4321
static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
K
KAMEZAWA Hiroyuki 已提交
4322
{
K
KAMEZAWA Hiroyuki 已提交
4323 4324
	struct mem_cgroup *iter;

4325
	for_each_mem_cgroup_tree(iter, memcg)
K
KAMEZAWA Hiroyuki 已提交
4326
		mem_cgroup_oom_notify_cb(iter);
K
KAMEZAWA Hiroyuki 已提交
4327 4328 4329 4330
}

static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
	struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
4331 4332
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4333 4334
	struct mem_cgroup_thresholds *thresholds;
	struct mem_cgroup_threshold_ary *new;
4335 4336
	int type = MEMFILE_TYPE(cft->private);
	u64 threshold, usage;
4337
	int i, size, ret;
4338 4339 4340 4341 4342 4343

	ret = res_counter_memparse_write_strategy(args, &threshold);
	if (ret)
		return ret;

	mutex_lock(&memcg->thresholds_lock);
4344

4345
	if (type == _MEM)
4346
		thresholds = &memcg->thresholds;
4347
	else if (type == _MEMSWAP)
4348
		thresholds = &memcg->memsw_thresholds;
4349 4350 4351 4352 4353 4354
	else
		BUG();

	usage = mem_cgroup_usage(memcg, type == _MEMSWAP);

	/* Check if a threshold crossed before adding a new one */
4355
	if (thresholds->primary)
4356 4357
		__mem_cgroup_threshold(memcg, type == _MEMSWAP);

4358
	size = thresholds->primary ? thresholds->primary->size + 1 : 1;
4359 4360

	/* Allocate memory for new array of thresholds */
4361
	new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
4362
			GFP_KERNEL);
4363
	if (!new) {
4364 4365 4366
		ret = -ENOMEM;
		goto unlock;
	}
4367
	new->size = size;
4368 4369

	/* Copy thresholds (if any) to new array */
4370 4371
	if (thresholds->primary) {
		memcpy(new->entries, thresholds->primary->entries, (size - 1) *
4372
				sizeof(struct mem_cgroup_threshold));
4373 4374
	}

4375
	/* Add new threshold */
4376 4377
	new->entries[size - 1].eventfd = eventfd;
	new->entries[size - 1].threshold = threshold;
4378 4379

	/* Sort thresholds. Registering of new threshold isn't time-critical */
4380
	sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
4381 4382 4383
			compare_thresholds, NULL);

	/* Find current threshold */
4384
	new->current_threshold = -1;
4385
	for (i = 0; i < size; i++) {
4386
		if (new->entries[i].threshold < usage) {
4387
			/*
4388 4389
			 * new->current_threshold will not be used until
			 * rcu_assign_pointer(), so it's safe to increment
4390 4391
			 * it here.
			 */
4392
			++new->current_threshold;
4393 4394 4395
		}
	}

4396 4397 4398 4399 4400
	/* Free old spare buffer and save old primary buffer as spare */
	kfree(thresholds->spare);
	thresholds->spare = thresholds->primary;

	rcu_assign_pointer(thresholds->primary, new);
4401

4402
	/* To be sure that nobody uses thresholds */
4403 4404 4405 4406 4407 4408 4409 4410
	synchronize_rcu();

unlock:
	mutex_unlock(&memcg->thresholds_lock);

	return ret;
}

4411
static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
K
KAMEZAWA Hiroyuki 已提交
4412
	struct cftype *cft, struct eventfd_ctx *eventfd)
4413 4414
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4415 4416
	struct mem_cgroup_thresholds *thresholds;
	struct mem_cgroup_threshold_ary *new;
4417 4418
	int type = MEMFILE_TYPE(cft->private);
	u64 usage;
4419
	int i, j, size;
4420 4421 4422

	mutex_lock(&memcg->thresholds_lock);
	if (type == _MEM)
4423
		thresholds = &memcg->thresholds;
4424
	else if (type == _MEMSWAP)
4425
		thresholds = &memcg->memsw_thresholds;
4426 4427 4428 4429 4430 4431 4432 4433 4434
	else
		BUG();

	/*
	 * Something went wrong if we trying to unregister a threshold
	 * if we don't have thresholds
	 */
	BUG_ON(!thresholds);

4435 4436 4437
	if (!thresholds->primary)
		goto unlock;

4438 4439 4440 4441 4442 4443
	usage = mem_cgroup_usage(memcg, type == _MEMSWAP);

	/* Check if a threshold crossed before removing */
	__mem_cgroup_threshold(memcg, type == _MEMSWAP);

	/* Calculate new number of threshold */
4444 4445 4446
	size = 0;
	for (i = 0; i < thresholds->primary->size; i++) {
		if (thresholds->primary->entries[i].eventfd != eventfd)
4447 4448 4449
			size++;
	}

4450
	new = thresholds->spare;
4451

4452 4453
	/* Set thresholds array to NULL if we don't have thresholds */
	if (!size) {
4454 4455
		kfree(new);
		new = NULL;
4456
		goto swap_buffers;
4457 4458
	}

4459
	new->size = size;
4460 4461

	/* Copy thresholds and find current threshold */
4462 4463 4464
	new->current_threshold = -1;
	for (i = 0, j = 0; i < thresholds->primary->size; i++) {
		if (thresholds->primary->entries[i].eventfd == eventfd)
4465 4466
			continue;

4467 4468
		new->entries[j] = thresholds->primary->entries[i];
		if (new->entries[j].threshold < usage) {
4469
			/*
4470
			 * new->current_threshold will not be used
4471 4472 4473
			 * until rcu_assign_pointer(), so it's safe to increment
			 * it here.
			 */
4474
			++new->current_threshold;
4475 4476 4477 4478
		}
		j++;
	}

4479
swap_buffers:
4480 4481 4482
	/* Swap primary and spare array */
	thresholds->spare = thresholds->primary;
	rcu_assign_pointer(thresholds->primary, new);
4483

4484
	/* To be sure that nobody uses thresholds */
4485
	synchronize_rcu();
4486
unlock:
4487 4488
	mutex_unlock(&memcg->thresholds_lock);
}
4489

K
KAMEZAWA Hiroyuki 已提交
4490 4491 4492 4493 4494 4495 4496 4497 4498 4499 4500 4501
static int mem_cgroup_oom_register_event(struct cgroup *cgrp,
	struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
	struct mem_cgroup_eventfd_list *event;
	int type = MEMFILE_TYPE(cft->private);

	BUG_ON(type != _OOM_TYPE);
	event = kmalloc(sizeof(*event),	GFP_KERNEL);
	if (!event)
		return -ENOMEM;

4502
	spin_lock(&memcg_oom_lock);
K
KAMEZAWA Hiroyuki 已提交
4503 4504 4505 4506 4507

	event->eventfd = eventfd;
	list_add(&event->list, &memcg->oom_notify);

	/* already in OOM ? */
4508
	if (atomic_read(&memcg->under_oom))
K
KAMEZAWA Hiroyuki 已提交
4509
		eventfd_signal(eventfd, 1);
4510
	spin_unlock(&memcg_oom_lock);
K
KAMEZAWA Hiroyuki 已提交
4511 4512 4513 4514

	return 0;
}

4515
static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
K
KAMEZAWA Hiroyuki 已提交
4516 4517
	struct cftype *cft, struct eventfd_ctx *eventfd)
{
4518
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
K
KAMEZAWA Hiroyuki 已提交
4519 4520 4521 4522 4523
	struct mem_cgroup_eventfd_list *ev, *tmp;
	int type = MEMFILE_TYPE(cft->private);

	BUG_ON(type != _OOM_TYPE);

4524
	spin_lock(&memcg_oom_lock);
K
KAMEZAWA Hiroyuki 已提交
4525

4526
	list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
K
KAMEZAWA Hiroyuki 已提交
4527 4528 4529 4530 4531 4532
		if (ev->eventfd == eventfd) {
			list_del(&ev->list);
			kfree(ev);
		}
	}

4533
	spin_unlock(&memcg_oom_lock);
K
KAMEZAWA Hiroyuki 已提交
4534 4535
}

4536 4537 4538
static int mem_cgroup_oom_control_read(struct cgroup *cgrp,
	struct cftype *cft,  struct cgroup_map_cb *cb)
{
4539
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4540

4541
	cb->fill(cb, "oom_kill_disable", memcg->oom_kill_disable);
4542

4543
	if (atomic_read(&memcg->under_oom))
4544 4545 4546 4547 4548 4549 4550 4551 4552
		cb->fill(cb, "under_oom", 1);
	else
		cb->fill(cb, "under_oom", 0);
	return 0;
}

static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
	struct cftype *cft, u64 val)
{
4553
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4554 4555 4556 4557 4558 4559 4560 4561 4562 4563 4564
	struct mem_cgroup *parent;

	/* cannot set to root cgroup and only 0 and 1 are allowed */
	if (!cgrp->parent || !((val == 0) || (val == 1)))
		return -EINVAL;

	parent = mem_cgroup_from_cont(cgrp->parent);

	cgroup_lock();
	/* oom-kill-disable is a flag for subhierarchy. */
	if ((parent->use_hierarchy) ||
4565
	    (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
4566 4567 4568
		cgroup_unlock();
		return -EINVAL;
	}
4569
	memcg->oom_kill_disable = val;
4570
	if (!val)
4571
		memcg_oom_recover(memcg);
4572 4573 4574 4575
	cgroup_unlock();
	return 0;
}

4576 4577 4578 4579 4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590 4591
#ifdef CONFIG_NUMA
static const struct file_operations mem_control_numa_stat_file_operations = {
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};

static int mem_control_numa_stat_open(struct inode *unused, struct file *file)
{
	struct cgroup *cont = file->f_dentry->d_parent->d_fsdata;

	file->f_op = &mem_control_numa_stat_file_operations;
	return single_open(file, mem_control_numa_stat_show, cont);
}
#endif /* CONFIG_NUMA */

4592 4593 4594
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
static int register_kmem_files(struct cgroup *cont, struct cgroup_subsys *ss)
{
G
Glauber Costa 已提交
4595 4596 4597 4598 4599 4600 4601
	/*
	 * Part of this would be better living in a separate allocation
	 * function, leaving us with just the cgroup tree population work.
	 * We, however, depend on state such as network's proto_list that
	 * is only initialized after cgroup creation. I found the less
	 * cumbersome way to deal with it to defer it all to populate time
	 */
4602
	return mem_cgroup_sockets_init(cont, ss);
4603 4604
};

4605
static void kmem_cgroup_destroy(struct cgroup *cont)
G
Glauber Costa 已提交
4606
{
4607
	mem_cgroup_sockets_destroy(cont);
G
Glauber Costa 已提交
4608
}
4609 4610 4611 4612 4613
#else
static int register_kmem_files(struct cgroup *cont, struct cgroup_subsys *ss)
{
	return 0;
}
G
Glauber Costa 已提交
4614

4615
static void kmem_cgroup_destroy(struct cgroup *cont)
G
Glauber Costa 已提交
4616 4617
{
}
4618 4619
#endif

B
Balbir Singh 已提交
4620 4621
static struct cftype mem_cgroup_files[] = {
	{
4622
		.name = "usage_in_bytes",
4623
		.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4624
		.read_u64 = mem_cgroup_read,
K
KAMEZAWA Hiroyuki 已提交
4625 4626
		.register_event = mem_cgroup_usage_register_event,
		.unregister_event = mem_cgroup_usage_unregister_event,
B
Balbir Singh 已提交
4627
	},
4628 4629
	{
		.name = "max_usage_in_bytes",
4630
		.private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4631
		.trigger = mem_cgroup_reset,
4632 4633
		.read_u64 = mem_cgroup_read,
	},
B
Balbir Singh 已提交
4634
	{
4635
		.name = "limit_in_bytes",
4636
		.private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4637
		.write_string = mem_cgroup_write,
4638
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
4639
	},
4640 4641 4642 4643 4644 4645
	{
		.name = "soft_limit_in_bytes",
		.private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
		.write_string = mem_cgroup_write,
		.read_u64 = mem_cgroup_read,
	},
B
Balbir Singh 已提交
4646 4647
	{
		.name = "failcnt",
4648
		.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4649
		.trigger = mem_cgroup_reset,
4650
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
4651
	},
4652 4653
	{
		.name = "stat",
4654
		.read_map = mem_control_stat_show,
4655
	},
4656 4657 4658 4659
	{
		.name = "force_empty",
		.trigger = mem_cgroup_force_empty_write,
	},
4660 4661 4662 4663 4664
	{
		.name = "use_hierarchy",
		.write_u64 = mem_cgroup_hierarchy_write,
		.read_u64 = mem_cgroup_hierarchy_read,
	},
K
KOSAKI Motohiro 已提交
4665 4666 4667 4668 4669
	{
		.name = "swappiness",
		.read_u64 = mem_cgroup_swappiness_read,
		.write_u64 = mem_cgroup_swappiness_write,
	},
4670 4671 4672 4673 4674
	{
		.name = "move_charge_at_immigrate",
		.read_u64 = mem_cgroup_move_charge_read,
		.write_u64 = mem_cgroup_move_charge_write,
	},
K
KAMEZAWA Hiroyuki 已提交
4675 4676
	{
		.name = "oom_control",
4677 4678
		.read_map = mem_cgroup_oom_control_read,
		.write_u64 = mem_cgroup_oom_control_write,
K
KAMEZAWA Hiroyuki 已提交
4679 4680 4681 4682
		.register_event = mem_cgroup_oom_register_event,
		.unregister_event = mem_cgroup_oom_unregister_event,
		.private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
	},
4683 4684 4685 4686
#ifdef CONFIG_NUMA
	{
		.name = "numa_stat",
		.open = mem_control_numa_stat_open,
4687
		.mode = S_IRUGO,
4688 4689
	},
#endif
B
Balbir Singh 已提交
4690 4691
};

4692 4693 4694 4695 4696 4697
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
static struct cftype memsw_cgroup_files[] = {
	{
		.name = "memsw.usage_in_bytes",
		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
		.read_u64 = mem_cgroup_read,
K
KAMEZAWA Hiroyuki 已提交
4698 4699
		.register_event = mem_cgroup_usage_register_event,
		.unregister_event = mem_cgroup_usage_unregister_event,
4700 4701 4702 4703 4704 4705 4706 4707 4708 4709 4710 4711 4712 4713 4714 4715 4716 4717 4718 4719 4720 4721 4722 4723 4724 4725 4726 4727 4728 4729 4730 4731 4732 4733 4734
	},
	{
		.name = "memsw.max_usage_in_bytes",
		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
		.trigger = mem_cgroup_reset,
		.read_u64 = mem_cgroup_read,
	},
	{
		.name = "memsw.limit_in_bytes",
		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
		.write_string = mem_cgroup_write,
		.read_u64 = mem_cgroup_read,
	},
	{
		.name = "memsw.failcnt",
		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
		.trigger = mem_cgroup_reset,
		.read_u64 = mem_cgroup_read,
	},
};

static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
{
	if (!do_swap_account)
		return 0;
	return cgroup_add_files(cont, ss, memsw_cgroup_files,
				ARRAY_SIZE(memsw_cgroup_files));
};
#else
static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
{
	return 0;
}
#endif

4735
static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
4736 4737
{
	struct mem_cgroup_per_node *pn;
4738
	struct mem_cgroup_per_zone *mz;
4739
	enum lru_list l;
4740
	int zone, tmp = node;
4741 4742 4743 4744 4745 4746 4747 4748
	/*
	 * This routine is called against possible nodes.
	 * But it's BUG to call kmalloc() against offline node.
	 *
	 * TODO: this routine can waste much memory for nodes which will
	 *       never be onlined. It's better to use memory hotplug callback
	 *       function.
	 */
4749 4750
	if (!node_state(node, N_NORMAL_MEMORY))
		tmp = -1;
4751
	pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4752 4753
	if (!pn)
		return 1;
4754 4755 4756

	for (zone = 0; zone < MAX_NR_ZONES; zone++) {
		mz = &pn->zoneinfo[zone];
4757
		for_each_lru(l)
4758
			INIT_LIST_HEAD(&mz->lruvec.lists[l]);
4759
		mz->usage_in_excess = 0;
4760
		mz->on_tree = false;
4761
		mz->mem = memcg;
4762
	}
4763
	memcg->info.nodeinfo[node] = pn;
4764 4765 4766
	return 0;
}

4767
static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
4768
{
4769
	kfree(memcg->info.nodeinfo[node]);
4770 4771
}

4772 4773 4774
static struct mem_cgroup *mem_cgroup_alloc(void)
{
	struct mem_cgroup *mem;
4775
	int size = sizeof(struct mem_cgroup);
4776

4777
	/* Can be very big if MAX_NUMNODES is very big */
4778
	if (size < PAGE_SIZE)
4779
		mem = kzalloc(size, GFP_KERNEL);
4780
	else
4781
		mem = vzalloc(size);
4782

4783 4784 4785
	if (!mem)
		return NULL;

4786
	mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4787 4788
	if (!mem->stat)
		goto out_free;
4789
	spin_lock_init(&mem->pcp_counter_lock);
4790
	return mem;
4791 4792 4793 4794 4795 4796 4797

out_free:
	if (size < PAGE_SIZE)
		kfree(mem);
	else
		vfree(mem);
	return NULL;
4798 4799
}

4800 4801 4802 4803 4804 4805 4806 4807 4808 4809 4810 4811 4812 4813 4814 4815 4816 4817 4818 4819 4820
/*
 * Helpers for freeing a vzalloc()ed mem_cgroup by RCU,
 * but in process context.  The work_freeing structure is overlaid
 * on the rcu_freeing structure, which itself is overlaid on memsw.
 */
static void vfree_work(struct work_struct *work)
{
	struct mem_cgroup *memcg;

	memcg = container_of(work, struct mem_cgroup, work_freeing);
	vfree(memcg);
}
static void vfree_rcu(struct rcu_head *rcu_head)
{
	struct mem_cgroup *memcg;

	memcg = container_of(rcu_head, struct mem_cgroup, rcu_freeing);
	INIT_WORK(&memcg->work_freeing, vfree_work);
	schedule_work(&memcg->work_freeing);
}

4821 4822 4823 4824 4825 4826 4827 4828 4829 4830 4831
/*
 * At destroying mem_cgroup, references from swap_cgroup can remain.
 * (scanning all at force_empty is too costly...)
 *
 * Instead of clearing all references at force_empty, we remember
 * the number of reference from swap_cgroup and free mem_cgroup when
 * it goes down to 0.
 *
 * Removal of cgroup itself succeeds regardless of refs from swap.
 */

4832
static void __mem_cgroup_free(struct mem_cgroup *memcg)
4833
{
K
KAMEZAWA Hiroyuki 已提交
4834 4835
	int node;

4836 4837
	mem_cgroup_remove_from_trees(memcg);
	free_css_id(&mem_cgroup_subsys, &memcg->css);
K
KAMEZAWA Hiroyuki 已提交
4838

B
Bob Liu 已提交
4839
	for_each_node(node)
4840
		free_mem_cgroup_per_zone_info(memcg, node);
K
KAMEZAWA Hiroyuki 已提交
4841

4842
	free_percpu(memcg->stat);
4843
	if (sizeof(struct mem_cgroup) < PAGE_SIZE)
4844
		kfree_rcu(memcg, rcu_freeing);
4845
	else
4846
		call_rcu(&memcg->rcu_freeing, vfree_rcu);
4847 4848
}

4849
static void mem_cgroup_get(struct mem_cgroup *memcg)
4850
{
4851
	atomic_inc(&memcg->refcnt);
4852 4853
}

4854
static void __mem_cgroup_put(struct mem_cgroup *memcg, int count)
4855
{
4856 4857 4858
	if (atomic_sub_and_test(count, &memcg->refcnt)) {
		struct mem_cgroup *parent = parent_mem_cgroup(memcg);
		__mem_cgroup_free(memcg);
4859 4860 4861
		if (parent)
			mem_cgroup_put(parent);
	}
4862 4863
}

4864
static void mem_cgroup_put(struct mem_cgroup *memcg)
4865
{
4866
	__mem_cgroup_put(memcg, 1);
4867 4868
}

4869 4870 4871
/*
 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
 */
G
Glauber Costa 已提交
4872
struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
4873
{
4874
	if (!memcg->res.parent)
4875
		return NULL;
4876
	return mem_cgroup_from_res_counter(memcg->res.parent, res);
4877
}
G
Glauber Costa 已提交
4878
EXPORT_SYMBOL(parent_mem_cgroup);
4879

4880 4881 4882
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
static void __init enable_swap_cgroup(void)
{
4883
	if (!mem_cgroup_disabled() && really_do_swap_account)
4884 4885 4886 4887 4888 4889 4890 4891
		do_swap_account = 1;
}
#else
static void __init enable_swap_cgroup(void)
{
}
#endif

4892 4893 4894 4895 4896 4897
static int mem_cgroup_soft_limit_tree_init(void)
{
	struct mem_cgroup_tree_per_node *rtpn;
	struct mem_cgroup_tree_per_zone *rtpz;
	int tmp, node, zone;

B
Bob Liu 已提交
4898
	for_each_node(node) {
4899 4900 4901 4902 4903
		tmp = node;
		if (!node_state(node, N_NORMAL_MEMORY))
			tmp = -1;
		rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
		if (!rtpn)
4904
			goto err_cleanup;
4905 4906 4907 4908 4909 4910 4911 4912 4913 4914

		soft_limit_tree.rb_tree_per_node[node] = rtpn;

		for (zone = 0; zone < MAX_NR_ZONES; zone++) {
			rtpz = &rtpn->rb_tree_per_zone[zone];
			rtpz->rb_root = RB_ROOT;
			spin_lock_init(&rtpz->lock);
		}
	}
	return 0;
4915 4916

err_cleanup:
B
Bob Liu 已提交
4917
	for_each_node(node) {
4918 4919 4920 4921 4922 4923 4924
		if (!soft_limit_tree.rb_tree_per_node[node])
			break;
		kfree(soft_limit_tree.rb_tree_per_node[node]);
		soft_limit_tree.rb_tree_per_node[node] = NULL;
	}
	return 1;

4925 4926
}

L
Li Zefan 已提交
4927
static struct cgroup_subsys_state * __ref
4928
mem_cgroup_create(struct cgroup *cont)
B
Balbir Singh 已提交
4929
{
4930
	struct mem_cgroup *memcg, *parent;
K
KAMEZAWA Hiroyuki 已提交
4931
	long error = -ENOMEM;
4932
	int node;
B
Balbir Singh 已提交
4933

4934 4935
	memcg = mem_cgroup_alloc();
	if (!memcg)
K
KAMEZAWA Hiroyuki 已提交
4936
		return ERR_PTR(error);
4937

B
Bob Liu 已提交
4938
	for_each_node(node)
4939
		if (alloc_mem_cgroup_per_zone_info(memcg, node))
4940
			goto free_out;
4941

4942
	/* root ? */
4943
	if (cont->parent == NULL) {
4944
		int cpu;
4945
		enable_swap_cgroup();
4946
		parent = NULL;
4947 4948
		if (mem_cgroup_soft_limit_tree_init())
			goto free_out;
4949
		root_mem_cgroup = memcg;
4950 4951 4952 4953 4954
		for_each_possible_cpu(cpu) {
			struct memcg_stock_pcp *stock =
						&per_cpu(memcg_stock, cpu);
			INIT_WORK(&stock->work, drain_local_stock);
		}
4955
		hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
4956
	} else {
4957
		parent = mem_cgroup_from_cont(cont->parent);
4958 4959
		memcg->use_hierarchy = parent->use_hierarchy;
		memcg->oom_kill_disable = parent->oom_kill_disable;
4960
	}
4961

4962
	if (parent && parent->use_hierarchy) {
4963 4964
		res_counter_init(&memcg->res, &parent->res);
		res_counter_init(&memcg->memsw, &parent->memsw);
4965 4966 4967 4968 4969 4970 4971
		/*
		 * We increment refcnt of the parent to ensure that we can
		 * safely access it on res_counter_charge/uncharge.
		 * This refcnt will be decremented when freeing this
		 * mem_cgroup(see mem_cgroup_put).
		 */
		mem_cgroup_get(parent);
4972
	} else {
4973 4974
		res_counter_init(&memcg->res, NULL);
		res_counter_init(&memcg->memsw, NULL);
4975
	}
4976 4977
	memcg->last_scanned_node = MAX_NUMNODES;
	INIT_LIST_HEAD(&memcg->oom_notify);
4978

K
KOSAKI Motohiro 已提交
4979
	if (parent)
4980 4981 4982 4983 4984
		memcg->swappiness = mem_cgroup_swappiness(parent);
	atomic_set(&memcg->refcnt, 1);
	memcg->move_charge_at_immigrate = 0;
	mutex_init(&memcg->thresholds_lock);
	return &memcg->css;
4985
free_out:
4986
	__mem_cgroup_free(memcg);
K
KAMEZAWA Hiroyuki 已提交
4987
	return ERR_PTR(error);
B
Balbir Singh 已提交
4988 4989
}

4990
static int mem_cgroup_pre_destroy(struct cgroup *cont)
4991
{
4992
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
4993

4994
	return mem_cgroup_force_empty(memcg, false);
4995 4996
}

4997
static void mem_cgroup_destroy(struct cgroup *cont)
B
Balbir Singh 已提交
4998
{
4999
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
5000

5001
	kmem_cgroup_destroy(cont);
G
Glauber Costa 已提交
5002

5003
	mem_cgroup_put(memcg);
B
Balbir Singh 已提交
5004 5005 5006 5007 5008
}

static int mem_cgroup_populate(struct cgroup_subsys *ss,
				struct cgroup *cont)
{
5009 5010 5011 5012 5013 5014 5015
	int ret;

	ret = cgroup_add_files(cont, ss, mem_cgroup_files,
				ARRAY_SIZE(mem_cgroup_files));

	if (!ret)
		ret = register_memsw_files(cont, ss);
5016 5017 5018 5019

	if (!ret)
		ret = register_kmem_files(cont, ss);

5020
	return ret;
B
Balbir Singh 已提交
5021 5022
}

5023
#ifdef CONFIG_MMU
5024
/* Handlers for move charge at task migration. */
5025 5026
#define PRECHARGE_COUNT_AT_ONCE	256
static int mem_cgroup_do_precharge(unsigned long count)
5027
{
5028 5029
	int ret = 0;
	int batch_count = PRECHARGE_COUNT_AT_ONCE;
5030
	struct mem_cgroup *memcg = mc.to;
5031

5032
	if (mem_cgroup_is_root(memcg)) {
5033 5034 5035 5036 5037 5038 5039 5040
		mc.precharge += count;
		/* we don't need css_get for root */
		return ret;
	}
	/* try to charge at once */
	if (count > 1) {
		struct res_counter *dummy;
		/*
5041
		 * "memcg" cannot be under rmdir() because we've already checked
5042 5043 5044 5045
		 * by cgroup_lock_live_cgroup() that it is not removed and we
		 * are still under the same cgroup_mutex. So we can postpone
		 * css_get().
		 */
5046
		if (res_counter_charge(&memcg->res, PAGE_SIZE * count, &dummy))
5047
			goto one_by_one;
5048
		if (do_swap_account && res_counter_charge(&memcg->memsw,
5049
						PAGE_SIZE * count, &dummy)) {
5050
			res_counter_uncharge(&memcg->res, PAGE_SIZE * count);
5051 5052 5053 5054 5055 5056 5057 5058 5059 5060 5061 5062 5063 5064 5065 5066
			goto one_by_one;
		}
		mc.precharge += count;
		return ret;
	}
one_by_one:
	/* fall back to one by one charge */
	while (count--) {
		if (signal_pending(current)) {
			ret = -EINTR;
			break;
		}
		if (!batch_count--) {
			batch_count = PRECHARGE_COUNT_AT_ONCE;
			cond_resched();
		}
5067 5068
		ret = __mem_cgroup_try_charge(NULL,
					GFP_KERNEL, 1, &memcg, false);
5069
		if (ret)
5070
			/* mem_cgroup_clear_mc() will do uncharge later */
5071
			return ret;
5072 5073
		mc.precharge++;
	}
5074 5075 5076 5077 5078 5079 5080 5081
	return ret;
}

/**
 * is_target_pte_for_mc - check a pte whether it is valid for move charge
 * @vma: the vma the pte to be checked belongs
 * @addr: the address corresponding to the pte to be checked
 * @ptent: the pte to be checked
5082
 * @target: the pointer the target page or swap ent will be stored(can be NULL)
5083 5084 5085 5086 5087 5088
 *
 * Returns
 *   0(MC_TARGET_NONE): if the pte is not a target for move charge.
 *   1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
 *     move charge. if @target is not NULL, the page is stored in target->page
 *     with extra refcnt got(Callers should handle it).
5089 5090 5091
 *   2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
 *     target for charge migration. if @target is not NULL, the entry is stored
 *     in target->ent.
5092 5093 5094 5095 5096
 *
 * Called with pte lock held.
 */
union mc_target {
	struct page	*page;
5097
	swp_entry_t	ent;
5098 5099 5100 5101 5102
};

enum mc_target_type {
	MC_TARGET_NONE,	/* not used */
	MC_TARGET_PAGE,
5103
	MC_TARGET_SWAP,
5104 5105
};

D
Daisuke Nishimura 已提交
5106 5107
static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
						unsigned long addr, pte_t ptent)
5108
{
D
Daisuke Nishimura 已提交
5109
	struct page *page = vm_normal_page(vma, addr, ptent);
5110

D
Daisuke Nishimura 已提交
5111 5112 5113 5114
	if (!page || !page_mapped(page))
		return NULL;
	if (PageAnon(page)) {
		/* we don't move shared anon */
5115
		if (!move_anon() || page_mapcount(page) > 2)
D
Daisuke Nishimura 已提交
5116
			return NULL;
5117 5118
	} else if (!move_file())
		/* we ignore mapcount for file pages */
D
Daisuke Nishimura 已提交
5119 5120 5121 5122 5123 5124 5125 5126 5127 5128 5129 5130 5131 5132 5133 5134 5135 5136
		return NULL;
	if (!get_page_unless_zero(page))
		return NULL;

	return page;
}

static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
			unsigned long addr, pte_t ptent, swp_entry_t *entry)
{
	int usage_count;
	struct page *page = NULL;
	swp_entry_t ent = pte_to_swp_entry(ptent);

	if (!move_anon() || non_swap_entry(ent))
		return NULL;
	usage_count = mem_cgroup_count_swap_user(ent, &page);
	if (usage_count > 1) { /* we don't move shared anon */
5137 5138
		if (page)
			put_page(page);
D
Daisuke Nishimura 已提交
5139
		return NULL;
5140
	}
D
Daisuke Nishimura 已提交
5141 5142 5143 5144 5145 5146
	if (do_swap_account)
		entry->val = ent.val;

	return page;
}

5147 5148 5149 5150 5151 5152 5153 5154 5155 5156 5157 5158 5159 5160 5161 5162 5163 5164 5165 5166 5167
static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
			unsigned long addr, pte_t ptent, swp_entry_t *entry)
{
	struct page *page = NULL;
	struct inode *inode;
	struct address_space *mapping;
	pgoff_t pgoff;

	if (!vma->vm_file) /* anonymous vma */
		return NULL;
	if (!move_file())
		return NULL;

	inode = vma->vm_file->f_path.dentry->d_inode;
	mapping = vma->vm_file->f_mapping;
	if (pte_none(ptent))
		pgoff = linear_page_index(vma, addr);
	else /* pte_file(ptent) is true */
		pgoff = pte_to_pgoff(ptent);

	/* page is moved even if it's not RSS of this task(page-faulted). */
5168 5169 5170 5171 5172 5173
	page = find_get_page(mapping, pgoff);

#ifdef CONFIG_SWAP
	/* shmem/tmpfs may report page out on swap: account for that too. */
	if (radix_tree_exceptional_entry(page)) {
		swp_entry_t swap = radix_to_swp_entry(page);
5174
		if (do_swap_account)
5175 5176
			*entry = swap;
		page = find_get_page(&swapper_space, swap.val);
5177
	}
5178
#endif
5179 5180 5181
	return page;
}

D
Daisuke Nishimura 已提交
5182 5183 5184 5185 5186 5187 5188 5189 5190 5191 5192 5193
static int is_target_pte_for_mc(struct vm_area_struct *vma,
		unsigned long addr, pte_t ptent, union mc_target *target)
{
	struct page *page = NULL;
	struct page_cgroup *pc;
	int ret = 0;
	swp_entry_t ent = { .val = 0 };

	if (pte_present(ptent))
		page = mc_handle_present_pte(vma, addr, ptent);
	else if (is_swap_pte(ptent))
		page = mc_handle_swap_pte(vma, addr, ptent, &ent);
5194 5195
	else if (pte_none(ptent) || pte_file(ptent))
		page = mc_handle_file_pte(vma, addr, ptent, &ent);
D
Daisuke Nishimura 已提交
5196 5197 5198

	if (!page && !ent.val)
		return 0;
5199 5200 5201 5202 5203 5204 5205 5206 5207 5208 5209 5210 5211 5212 5213
	if (page) {
		pc = lookup_page_cgroup(page);
		/*
		 * Do only loose check w/o page_cgroup lock.
		 * mem_cgroup_move_account() checks the pc is valid or not under
		 * the lock.
		 */
		if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
			ret = MC_TARGET_PAGE;
			if (target)
				target->page = page;
		}
		if (!ret || !target)
			put_page(page);
	}
D
Daisuke Nishimura 已提交
5214 5215
	/* There is a swap entry and a page doesn't exist or isn't charged */
	if (ent.val && !ret &&
5216
			css_id(&mc.from->css) == lookup_swap_cgroup_id(ent)) {
5217 5218 5219
		ret = MC_TARGET_SWAP;
		if (target)
			target->ent = ent;
5220 5221 5222 5223 5224 5225 5226 5227 5228 5229 5230 5231
	}
	return ret;
}

static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
					unsigned long addr, unsigned long end,
					struct mm_walk *walk)
{
	struct vm_area_struct *vma = walk->private;
	pte_t *pte;
	spinlock_t *ptl;

5232
	split_huge_page_pmd(walk->mm, pmd);
5233 5234
	if (pmd_trans_unstable(pmd))
		return 0;
5235

5236 5237 5238 5239 5240 5241 5242
	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
	for (; addr != end; pte++, addr += PAGE_SIZE)
		if (is_target_pte_for_mc(vma, addr, *pte, NULL))
			mc.precharge++;	/* increment precharge temporarily */
	pte_unmap_unlock(pte - 1, ptl);
	cond_resched();

5243 5244 5245
	return 0;
}

5246 5247 5248 5249 5250
static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
{
	unsigned long precharge;
	struct vm_area_struct *vma;

5251
	down_read(&mm->mmap_sem);
5252 5253 5254 5255 5256 5257 5258 5259 5260 5261 5262
	for (vma = mm->mmap; vma; vma = vma->vm_next) {
		struct mm_walk mem_cgroup_count_precharge_walk = {
			.pmd_entry = mem_cgroup_count_precharge_pte_range,
			.mm = mm,
			.private = vma,
		};
		if (is_vm_hugetlb_page(vma))
			continue;
		walk_page_range(vma->vm_start, vma->vm_end,
					&mem_cgroup_count_precharge_walk);
	}
5263
	up_read(&mm->mmap_sem);
5264 5265 5266 5267 5268 5269 5270 5271 5272

	precharge = mc.precharge;
	mc.precharge = 0;

	return precharge;
}

static int mem_cgroup_precharge_mc(struct mm_struct *mm)
{
5273 5274 5275 5276 5277
	unsigned long precharge = mem_cgroup_count_precharge(mm);

	VM_BUG_ON(mc.moving_task);
	mc.moving_task = current;
	return mem_cgroup_do_precharge(precharge);
5278 5279
}

5280 5281
/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
static void __mem_cgroup_clear_mc(void)
5282
{
5283 5284 5285
	struct mem_cgroup *from = mc.from;
	struct mem_cgroup *to = mc.to;

5286
	/* we must uncharge all the leftover precharges from mc.to */
5287 5288 5289 5290 5291 5292 5293 5294 5295 5296 5297
	if (mc.precharge) {
		__mem_cgroup_cancel_charge(mc.to, mc.precharge);
		mc.precharge = 0;
	}
	/*
	 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
	 * we must uncharge here.
	 */
	if (mc.moved_charge) {
		__mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
		mc.moved_charge = 0;
5298
	}
5299 5300 5301 5302 5303 5304 5305 5306 5307 5308 5309 5310 5311 5312 5313 5314 5315 5316 5317
	/* we must fixup refcnts and charges */
	if (mc.moved_swap) {
		/* uncharge swap account from the old cgroup */
		if (!mem_cgroup_is_root(mc.from))
			res_counter_uncharge(&mc.from->memsw,
						PAGE_SIZE * mc.moved_swap);
		__mem_cgroup_put(mc.from, mc.moved_swap);

		if (!mem_cgroup_is_root(mc.to)) {
			/*
			 * we charged both to->res and to->memsw, so we should
			 * uncharge to->res.
			 */
			res_counter_uncharge(&mc.to->res,
						PAGE_SIZE * mc.moved_swap);
		}
		/* we've already done mem_cgroup_get(mc.to) */
		mc.moved_swap = 0;
	}
5318 5319 5320 5321 5322 5323 5324 5325 5326 5327 5328 5329 5330 5331 5332
	memcg_oom_recover(from);
	memcg_oom_recover(to);
	wake_up_all(&mc.waitq);
}

static void mem_cgroup_clear_mc(void)
{
	struct mem_cgroup *from = mc.from;

	/*
	 * we must clear moving_task before waking up waiters at the end of
	 * task migration.
	 */
	mc.moving_task = NULL;
	__mem_cgroup_clear_mc();
5333
	spin_lock(&mc.lock);
5334 5335
	mc.from = NULL;
	mc.to = NULL;
5336
	spin_unlock(&mc.lock);
5337
	mem_cgroup_end_move(from);
5338 5339
}

5340 5341
static int mem_cgroup_can_attach(struct cgroup *cgroup,
				 struct cgroup_taskset *tset)
5342
{
5343
	struct task_struct *p = cgroup_taskset_first(tset);
5344
	int ret = 0;
5345
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgroup);
5346

5347
	if (memcg->move_charge_at_immigrate) {
5348 5349 5350
		struct mm_struct *mm;
		struct mem_cgroup *from = mem_cgroup_from_task(p);

5351
		VM_BUG_ON(from == memcg);
5352 5353 5354 5355 5356

		mm = get_task_mm(p);
		if (!mm)
			return 0;
		/* We move charges only when we move a owner of the mm */
5357 5358 5359 5360
		if (mm->owner == p) {
			VM_BUG_ON(mc.from);
			VM_BUG_ON(mc.to);
			VM_BUG_ON(mc.precharge);
5361
			VM_BUG_ON(mc.moved_charge);
5362
			VM_BUG_ON(mc.moved_swap);
5363
			mem_cgroup_start_move(from);
5364
			spin_lock(&mc.lock);
5365
			mc.from = from;
5366
			mc.to = memcg;
5367
			spin_unlock(&mc.lock);
5368
			/* We set mc.moving_task later */
5369 5370 5371 5372

			ret = mem_cgroup_precharge_mc(mm);
			if (ret)
				mem_cgroup_clear_mc();
5373 5374
		}
		mmput(mm);
5375 5376 5377 5378
	}
	return ret;
}

5379 5380
static void mem_cgroup_cancel_attach(struct cgroup *cgroup,
				     struct cgroup_taskset *tset)
5381
{
5382
	mem_cgroup_clear_mc();
5383 5384
}

5385 5386 5387
static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
				unsigned long addr, unsigned long end,
				struct mm_walk *walk)
5388
{
5389 5390 5391 5392 5393
	int ret = 0;
	struct vm_area_struct *vma = walk->private;
	pte_t *pte;
	spinlock_t *ptl;

5394
	split_huge_page_pmd(walk->mm, pmd);
5395 5396
	if (pmd_trans_unstable(pmd))
		return 0;
5397 5398 5399 5400 5401 5402 5403 5404
retry:
	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
	for (; addr != end; addr += PAGE_SIZE) {
		pte_t ptent = *(pte++);
		union mc_target target;
		int type;
		struct page *page;
		struct page_cgroup *pc;
5405
		swp_entry_t ent;
5406 5407 5408 5409 5410 5411 5412 5413 5414 5415 5416

		if (!mc.precharge)
			break;

		type = is_target_pte_for_mc(vma, addr, ptent, &target);
		switch (type) {
		case MC_TARGET_PAGE:
			page = target.page;
			if (isolate_lru_page(page))
				goto put;
			pc = lookup_page_cgroup(page);
5417 5418
			if (!mem_cgroup_move_account(page, 1, pc,
						     mc.from, mc.to, false)) {
5419
				mc.precharge--;
5420 5421
				/* we uncharge from mc.from later. */
				mc.moved_charge++;
5422 5423 5424 5425 5426
			}
			putback_lru_page(page);
put:			/* is_target_pte_for_mc() gets the page */
			put_page(page);
			break;
5427 5428
		case MC_TARGET_SWAP:
			ent = target.ent;
5429 5430
			if (!mem_cgroup_move_swap_account(ent,
						mc.from, mc.to, false)) {
5431
				mc.precharge--;
5432 5433 5434
				/* we fixup refcnts and charges later. */
				mc.moved_swap++;
			}
5435
			break;
5436 5437 5438 5439 5440 5441 5442 5443 5444 5445 5446 5447 5448 5449
		default:
			break;
		}
	}
	pte_unmap_unlock(pte - 1, ptl);
	cond_resched();

	if (addr != end) {
		/*
		 * We have consumed all precharges we got in can_attach().
		 * We try charge one by one, but don't do any additional
		 * charges to mc.to if we have failed in charge once in attach()
		 * phase.
		 */
5450
		ret = mem_cgroup_do_precharge(1);
5451 5452 5453 5454 5455 5456 5457 5458 5459 5460 5461 5462
		if (!ret)
			goto retry;
	}

	return ret;
}

static void mem_cgroup_move_charge(struct mm_struct *mm)
{
	struct vm_area_struct *vma;

	lru_add_drain_all();
5463 5464 5465 5466 5467 5468 5469 5470 5471 5472 5473 5474 5475
retry:
	if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
		/*
		 * Someone who are holding the mmap_sem might be waiting in
		 * waitq. So we cancel all extra charges, wake up all waiters,
		 * and retry. Because we cancel precharges, we might not be able
		 * to move enough charges, but moving charge is a best-effort
		 * feature anyway, so it wouldn't be a big problem.
		 */
		__mem_cgroup_clear_mc();
		cond_resched();
		goto retry;
	}
5476 5477 5478 5479 5480 5481 5482 5483 5484 5485 5486 5487 5488 5489 5490 5491 5492 5493
	for (vma = mm->mmap; vma; vma = vma->vm_next) {
		int ret;
		struct mm_walk mem_cgroup_move_charge_walk = {
			.pmd_entry = mem_cgroup_move_charge_pte_range,
			.mm = mm,
			.private = vma,
		};
		if (is_vm_hugetlb_page(vma))
			continue;
		ret = walk_page_range(vma->vm_start, vma->vm_end,
						&mem_cgroup_move_charge_walk);
		if (ret)
			/*
			 * means we have consumed all precharges and failed in
			 * doing additional charge. Just abandon here.
			 */
			break;
	}
5494
	up_read(&mm->mmap_sem);
5495 5496
}

5497 5498
static void mem_cgroup_move_task(struct cgroup *cont,
				 struct cgroup_taskset *tset)
B
Balbir Singh 已提交
5499
{
5500
	struct task_struct *p = cgroup_taskset_first(tset);
5501
	struct mm_struct *mm = get_task_mm(p);
5502 5503

	if (mm) {
5504 5505 5506
		if (mc.to)
			mem_cgroup_move_charge(mm);
		put_swap_token(mm);
5507 5508
		mmput(mm);
	}
5509 5510
	if (mc.to)
		mem_cgroup_clear_mc();
B
Balbir Singh 已提交
5511
}
5512
#else	/* !CONFIG_MMU */
5513 5514
static int mem_cgroup_can_attach(struct cgroup *cgroup,
				 struct cgroup_taskset *tset)
5515 5516 5517
{
	return 0;
}
5518 5519
static void mem_cgroup_cancel_attach(struct cgroup *cgroup,
				     struct cgroup_taskset *tset)
5520 5521
{
}
5522 5523
static void mem_cgroup_move_task(struct cgroup *cont,
				 struct cgroup_taskset *tset)
5524 5525 5526
{
}
#endif
B
Balbir Singh 已提交
5527

B
Balbir Singh 已提交
5528 5529 5530 5531
struct cgroup_subsys mem_cgroup_subsys = {
	.name = "memory",
	.subsys_id = mem_cgroup_subsys_id,
	.create = mem_cgroup_create,
5532
	.pre_destroy = mem_cgroup_pre_destroy,
B
Balbir Singh 已提交
5533 5534
	.destroy = mem_cgroup_destroy,
	.populate = mem_cgroup_populate,
5535 5536
	.can_attach = mem_cgroup_can_attach,
	.cancel_attach = mem_cgroup_cancel_attach,
B
Balbir Singh 已提交
5537
	.attach = mem_cgroup_move_task,
5538
	.early_init = 0,
K
KAMEZAWA Hiroyuki 已提交
5539
	.use_id = 1,
B
Balbir Singh 已提交
5540
};
5541 5542

#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
5543 5544 5545
static int __init enable_swap_account(char *s)
{
	/* consider enabled if no parameter or 1 is given */
5546
	if (!strcmp(s, "1"))
5547
		really_do_swap_account = 1;
5548
	else if (!strcmp(s, "0"))
5549 5550 5551
		really_do_swap_account = 0;
	return 1;
}
5552
__setup("swapaccount=", enable_swap_account);
5553 5554

#endif