memcontrol.c 127.9 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/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 <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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/*
 * Per memcg event counter is incremented at every pagein/pageout. This counter
 * is used for trigger some periodic events. This is straightforward and better
 * than using jiffies etc. to handle periodic memcg event.
 *
 * These values will be used as !((event) & ((1 <<(thresh)) - 1))
 */
#define THRESHOLDS_EVENTS_THRESH (7) /* once in 128 */
#define SOFTLIMIT_EVENTS_THRESH (10) /* once in 1024 */
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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_PGPGIN_COUNT,	/* # of pages paged in */
	MEM_CGROUP_STAT_PGPGOUT_COUNT,	/* # of pages paged out */
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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 */
	/* incremented at every  pagein/pageout */
	MEM_CGROUP_EVENTS = MEM_CGROUP_STAT_DATA,
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	MEM_CGROUP_ON_MOVE,	/* someone is moving account between groups */
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	MEM_CGROUP_STAT_NSTATS,
};

struct mem_cgroup_stat_cpu {
	s64 count[MEM_CGROUP_STAT_NSTATS];
};

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/*
 * per-zone information in memory controller.
 */
struct mem_cgroup_per_zone {
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	/*
	 * spin_lock to protect the per cgroup LRU
	 */
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	struct list_head	lists[NR_LRU_LISTS];
	unsigned long		count[NR_LRU_LISTS];
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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 *mem);
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static void mem_cgroup_oom_notify(struct mem_cgroup *mem);
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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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	/*
	 * the counter to account for mem+swap usage.
	 */
	struct res_counter memsw;
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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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	/*
	  protect against reclaim related member.
	*/
	spinlock_t reclaim_param_lock;

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	/*
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	 * While reclaiming in a hierarchy, we cache the last child we
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	 * reclaimed from.
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	 */
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	int last_scanned_child;
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	/*
	 * Should the accounting and control be hierarchical, per subtree?
	 */
	bool use_hierarchy;
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	atomic_t	oom_lock;
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	atomic_t	refcnt;
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	unsigned 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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};

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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 */
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	struct mm_struct *mm;
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	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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/* only for here (for easy reading.) */
#define PCGF_CACHE	(1UL << PCG_CACHE)
#define PCGF_USED	(1UL << PCG_USED)
#define PCGF_LOCK	(1UL << PCG_LOCK)
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/* Not used, but added here for completeness */
#define PCGF_ACCT	(1UL << PCG_ACCT)
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/* for encoding cft->private value on file */
#define _MEM			(0)
#define _MEMSWAP		(1)
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#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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#define MEM_CGROUP_RECLAIM_SOFT_BIT	0x2
#define MEM_CGROUP_RECLAIM_SOFT		(1 << MEM_CGROUP_RECLAIM_SOFT_BIT)
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static void mem_cgroup_get(struct mem_cgroup *mem);
static void mem_cgroup_put(struct mem_cgroup *mem);
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static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
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static void drain_all_stock_async(void);
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static struct mem_cgroup_per_zone *
mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
{
	return &mem->info.nodeinfo[nid]->zoneinfo[zid];
}

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

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static struct mem_cgroup_per_zone *
page_cgroup_zoneinfo(struct page_cgroup *pc)
{
	struct mem_cgroup *mem = pc->mem_cgroup;
	int nid = page_cgroup_nid(pc);
	int zid = page_cgroup_zid(pc);

	if (!mem)
		return NULL;

	return mem_cgroup_zoneinfo(mem, nid, zid);
}

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 *mem,
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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
__mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
				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
mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
				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(mem, mz, mctz);
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	spin_unlock(&mctz->lock);
}


static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
{
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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 (; mem; mem = parent_mem_cgroup(mem)) {
		mz = mem_cgroup_zoneinfo(mem, nid, zid);
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		excess = res_counter_soft_limit_excess(&mem->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)
				__mem_cgroup_remove_exceeded(mem, mz, mctz);
			/*
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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(mem, mz, mctz, excess);
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			spin_unlock(&mctz->lock);
		}
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	}
}

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

	for_each_node_state(node, N_POSSIBLE) {
		for (zone = 0; zone < MAX_NR_ZONES; zone++) {
			mz = mem_cgroup_zoneinfo(mem, node, zone);
			mctz = soft_limit_tree_node_zone(node, zone);
			mem_cgroup_remove_exceeded(mem, mz, mctz);
		}
	}
}

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static inline unsigned long mem_cgroup_get_excess(struct mem_cgroup *mem)
{
	return res_counter_soft_limit_excess(&mem->res) >> PAGE_SHIFT;
}

static struct mem_cgroup_per_zone *
__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
{
	struct rb_node *rightmost = NULL;
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	struct mem_cgroup_per_zone *mz;
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retry:
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	mz = NULL;
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	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;
}

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/*
 * 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.
 */
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static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
		enum mem_cgroup_stat_index idx)
{
	int cpu;
	s64 val = 0;

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	get_online_cpus();
	for_each_online_cpu(cpu)
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		val += per_cpu(mem->stat->count[idx], cpu);
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#ifdef CONFIG_HOTPLUG_CPU
	spin_lock(&mem->pcp_counter_lock);
	val += mem->nocpu_base.count[idx];
	spin_unlock(&mem->pcp_counter_lock);
#endif
	put_online_cpus();
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	return val;
}

static s64 mem_cgroup_local_usage(struct mem_cgroup *mem)
{
	s64 ret;

	ret = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
	ret += mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
	return ret;
}

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static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,
					 bool charge)
{
	int val = (charge) ? 1 : -1;
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	this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_SWAPOUT], val);
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}

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static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
					 struct page_cgroup *pc,
					 bool charge)
606
{
607
	int val = (charge) ? 1 : -1;
608

609 610
	preempt_disable();

611
	if (PageCgroupCache(pc))
612
		__this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], val);
613
	else
614
		__this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], val);
615 616

	if (charge)
617
		__this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGIN_COUNT]);
618
	else
619
		__this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGOUT_COUNT]);
620
	__this_cpu_inc(mem->stat->count[MEM_CGROUP_EVENTS]);
621

622
	preempt_enable();
623 624
}

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static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
626
					enum lru_list idx)
627 628 629 630 631 632 633 634 635 636 637
{
	int nid, zid;
	struct mem_cgroup_per_zone *mz;
	u64 total = 0;

	for_each_online_node(nid)
		for (zid = 0; zid < MAX_NR_ZONES; zid++) {
			mz = mem_cgroup_zoneinfo(mem, nid, zid);
			total += MEM_CGROUP_ZSTAT(mz, idx);
		}
	return total;
638 639
}

640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662
static bool __memcg_event_check(struct mem_cgroup *mem, int event_mask_shift)
{
	s64 val;

	val = this_cpu_read(mem->stat->count[MEM_CGROUP_EVENTS]);

	return !(val & ((1 << event_mask_shift) - 1));
}

/*
 * Check events in order.
 *
 */
static void memcg_check_events(struct mem_cgroup *mem, struct page *page)
{
	/* threshold event is triggered in finer grain than soft limit */
	if (unlikely(__memcg_event_check(mem, THRESHOLDS_EVENTS_THRESH))) {
		mem_cgroup_threshold(mem);
		if (unlikely(__memcg_event_check(mem, SOFTLIMIT_EVENTS_THRESH)))
			mem_cgroup_update_tree(mem, page);
	}
}

663
static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
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{
	return container_of(cgroup_subsys_state(cont,
				mem_cgroup_subsys_id), struct mem_cgroup,
				css);
}

670
struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
671
{
672 673 674 675 676 677 678 679
	/*
	 * 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;

680 681 682 683
	return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
				struct mem_cgroup, css);
}

684 685 686
static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
{
	struct mem_cgroup *mem = NULL;
687 688 689

	if (!mm)
		return NULL;
690 691 692 693 694 695 696 697 698 699 700 701 702 703 704
	/*
	 * 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 {
		mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
		if (unlikely(!mem))
			break;
	} while (!css_tryget(&mem->css));
	rcu_read_unlock();
	return mem;
}

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/* The caller has to guarantee "mem" exists before calling this */
static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *mem)
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{
708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729
	struct cgroup_subsys_state *css;
	int found;

	if (!mem) /* ROOT cgroup has the smallest ID */
		return root_mem_cgroup; /*css_put/get against root is ignored*/
	if (!mem->use_hierarchy) {
		if (css_tryget(&mem->css))
			return mem;
		return NULL;
	}
	rcu_read_lock();
	/*
	 * searching a memory cgroup which has the smallest ID under given
	 * ROOT cgroup. (ID >= 1)
	 */
	css = css_get_next(&mem_cgroup_subsys, 1, &mem->css, &found);
	if (css && css_tryget(css))
		mem = container_of(css, struct mem_cgroup, css);
	else
		mem = NULL;
	rcu_read_unlock();
	return mem;
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}

static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter,
					struct mem_cgroup *root,
					bool cond)
{
	int nextid = css_id(&iter->css) + 1;
	int found;
	int hierarchy_used;
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	struct cgroup_subsys_state *css;

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	hierarchy_used = iter->use_hierarchy;
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	css_put(&iter->css);
744 745
	/* If no ROOT, walk all, ignore hierarchy */
	if (!cond || (root && !hierarchy_used))
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		return NULL;
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748 749 750
	if (!root)
		root = root_mem_cgroup;

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	do {
		iter = NULL;
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		rcu_read_lock();
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		css = css_get_next(&mem_cgroup_subsys, nextid,
				&root->css, &found);
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		if (css && css_tryget(css))
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			iter = container_of(css, struct mem_cgroup, css);
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		rcu_read_unlock();
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		/* If css is NULL, no more cgroups will be found */
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		nextid = found + 1;
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	} while (css && !iter);
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	return iter;
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}
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/*
 * for_eacn_mem_cgroup_tree() for visiting all cgroup under tree. Please
 * be careful that "break" loop is not allowed. We have reference count.
 * Instead of that modify "cond" to be false and "continue" to exit the loop.
 */
#define for_each_mem_cgroup_tree_cond(iter, root, cond)	\
	for (iter = mem_cgroup_start_loop(root);\
	     iter != NULL;\
	     iter = mem_cgroup_get_next(iter, root, cond))

#define for_each_mem_cgroup_tree(iter, root) \
	for_each_mem_cgroup_tree_cond(iter, root, true)

779 780 781
#define for_each_mem_cgroup_all(iter) \
	for_each_mem_cgroup_tree_cond(iter, NULL, true)

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783 784 785 786 787
static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
{
	return (mem == root_mem_cgroup);
}

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/*
 * 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.
 */
801

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void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
{
	struct page_cgroup *pc;
	struct mem_cgroup_per_zone *mz;
806

807
	if (mem_cgroup_disabled())
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		return;
	pc = lookup_page_cgroup(page);
	/* can happen while we handle swapcache. */
811
	if (!TestClearPageCgroupAcctLRU(pc))
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		return;
813
	VM_BUG_ON(!pc->mem_cgroup);
814 815 816 817
	/*
	 * We don't check PCG_USED bit. It's cleared when the "page" is finally
	 * removed from global LRU.
	 */
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	mz = page_cgroup_zoneinfo(pc);
819
	MEM_CGROUP_ZSTAT(mz, lru) -= 1;
820 821 822
	if (mem_cgroup_is_root(pc->mem_cgroup))
		return;
	VM_BUG_ON(list_empty(&pc->lru));
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	list_del_init(&pc->lru);
	return;
825 826
}

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void mem_cgroup_del_lru(struct page *page)
828
{
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	mem_cgroup_del_lru_list(page, page_lru(page));
}
831

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void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
{
	struct mem_cgroup_per_zone *mz;
	struct page_cgroup *pc;
836

837
	if (mem_cgroup_disabled())
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		return;
839

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	pc = lookup_page_cgroup(page);
841 842 843 844
	/*
	 * Used bit is set without atomic ops but after smp_wmb().
	 * For making pc->mem_cgroup visible, insert smp_rmb() here.
	 */
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	smp_rmb();
846 847
	/* unused or root page is not rotated. */
	if (!PageCgroupUsed(pc) || mem_cgroup_is_root(pc->mem_cgroup))
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		return;
	mz = page_cgroup_zoneinfo(pc);
	list_move(&pc->lru, &mz->lists[lru]);
851 852
}

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void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
854
{
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	struct page_cgroup *pc;
	struct mem_cgroup_per_zone *mz;
857

858
	if (mem_cgroup_disabled())
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		return;
	pc = lookup_page_cgroup(page);
861
	VM_BUG_ON(PageCgroupAcctLRU(pc));
862 863 864 865
	/*
	 * Used bit is set without atomic ops but after smp_wmb().
	 * For making pc->mem_cgroup visible, insert smp_rmb() here.
	 */
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	smp_rmb();
	if (!PageCgroupUsed(pc))
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		return;
869

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	mz = page_cgroup_zoneinfo(pc);
871
	MEM_CGROUP_ZSTAT(mz, lru) += 1;
872 873 874
	SetPageCgroupAcctLRU(pc);
	if (mem_cgroup_is_root(pc->mem_cgroup))
		return;
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	list_add(&pc->lru, &mz->lists[lru]);
}
877

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/*
879 880 881 882 883
 * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to
 * lru because the page may.be reused after it's fully uncharged (because of
 * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge
 * it again. This function is only used to charge SwapCache. It's done under
 * lock_page and expected that zone->lru_lock is never held.
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 */
885
static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page)
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{
887 888 889 890 891 892 893 894 895 896 897 898
	unsigned long flags;
	struct zone *zone = page_zone(page);
	struct page_cgroup *pc = lookup_page_cgroup(page);

	spin_lock_irqsave(&zone->lru_lock, flags);
	/*
	 * Forget old LRU when this page_cgroup is *not* used. This Used bit
	 * is guarded by lock_page() because the page is SwapCache.
	 */
	if (!PageCgroupUsed(pc))
		mem_cgroup_del_lru_list(page, page_lru(page));
	spin_unlock_irqrestore(&zone->lru_lock, flags);
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}

901 902 903 904 905 906 907 908
static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page)
{
	unsigned long flags;
	struct zone *zone = page_zone(page);
	struct page_cgroup *pc = lookup_page_cgroup(page);

	spin_lock_irqsave(&zone->lru_lock, flags);
	/* link when the page is linked to LRU but page_cgroup isn't */
909
	if (PageLRU(page) && !PageCgroupAcctLRU(pc))
910 911 912 913 914
		mem_cgroup_add_lru_list(page, page_lru(page));
	spin_unlock_irqrestore(&zone->lru_lock, flags);
}


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void mem_cgroup_move_lists(struct page *page,
			   enum lru_list from, enum lru_list to)
{
918
	if (mem_cgroup_disabled())
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		return;
	mem_cgroup_del_lru_list(page, from);
	mem_cgroup_add_lru_list(page, to);
922 923
}

924 925 926
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
{
	int ret;
927
	struct mem_cgroup *curr = NULL;
928
	struct task_struct *p;
929

930 931 932 933 934
	p = find_lock_task_mm(task);
	if (!p)
		return 0;
	curr = try_get_mem_cgroup_from_mm(p->mm);
	task_unlock(p);
935 936
	if (!curr)
		return 0;
937 938 939 940 941 942 943
	/*
	 * We should check use_hierarchy of "mem" not "curr". Because checking
	 * use_hierarchy of "curr" here make this function true if hierarchy is
	 * enabled in "curr" and "curr" is a child of "mem" in *cgroup*
	 * hierarchy(even if use_hierarchy is disabled in "mem").
	 */
	if (mem->use_hierarchy)
944 945 946 947
		ret = css_is_ancestor(&curr->css, &mem->css);
	else
		ret = (curr == mem);
	css_put(&curr->css);
948 949 950
	return ret;
}

951
static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
952 953 954
{
	unsigned long active;
	unsigned long inactive;
955 956
	unsigned long gb;
	unsigned long inactive_ratio;
957

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	inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON);
	active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON);
960

961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987
	gb = (inactive + active) >> (30 - PAGE_SHIFT);
	if (gb)
		inactive_ratio = int_sqrt(10 * gb);
	else
		inactive_ratio = 1;

	if (present_pages) {
		present_pages[0] = inactive;
		present_pages[1] = active;
	}

	return inactive_ratio;
}

int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
{
	unsigned long active;
	unsigned long inactive;
	unsigned long present_pages[2];
	unsigned long inactive_ratio;

	inactive_ratio = calc_inactive_ratio(memcg, present_pages);

	inactive = present_pages[0];
	active = present_pages[1];

	if (inactive * inactive_ratio < active)
988 989 990 991 992
		return 1;

	return 0;
}

993 994 995 996 997 998 999 1000 1001 1002 1003
int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)
{
	unsigned long active;
	unsigned long inactive;

	inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_FILE);
	active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_FILE);

	return (active > inactive);
}

1004 1005 1006 1007
unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
				       struct zone *zone,
				       enum lru_list lru)
{
1008
	int nid = zone_to_nid(zone);
1009 1010 1011 1012 1013 1014
	int zid = zone_idx(zone);
	struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);

	return MEM_CGROUP_ZSTAT(mz, lru);
}

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struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
						      struct zone *zone)
{
1018
	int nid = zone_to_nid(zone);
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	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;
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	int page_size = PAGE_SIZE;

	if (PageTransHuge(page))
		page_size <<= compound_order(page);
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	if (mem_cgroup_disabled())
		return NULL;

	pc = lookup_page_cgroup(page);
1039 1040 1041 1042 1043 1044 1045 1046
	/*
	 * Used bit is set without atomic ops but after smp_wmb().
	 * For making pc->mem_cgroup visible, insert smp_rmb() here.
	 */
	smp_rmb();
	if (!PageCgroupUsed(pc))
		return NULL;

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	mz = page_cgroup_zoneinfo(pc);
	if (!mz)
		return NULL;

	return &mz->reclaim_stat;
}

1054 1055 1056 1057 1058
unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
					struct list_head *dst,
					unsigned long *scanned, int order,
					int mode, struct zone *z,
					struct mem_cgroup *mem_cont,
1059
					int active, int file)
1060 1061 1062 1063 1064 1065
{
	unsigned long nr_taken = 0;
	struct page *page;
	unsigned long scan;
	LIST_HEAD(pc_list);
	struct list_head *src;
1066
	struct page_cgroup *pc, *tmp;
1067
	int nid = zone_to_nid(z);
1068 1069
	int zid = zone_idx(z);
	struct mem_cgroup_per_zone *mz;
1070
	int lru = LRU_FILE * file + active;
1071
	int ret;
1072

1073
	BUG_ON(!mem_cont);
1074
	mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
1075
	src = &mz->lists[lru];
1076

1077 1078
	scan = 0;
	list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
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		if (scan >= nr_to_scan)
1080
			break;
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		page = pc->page;
1083 1084
		if (unlikely(!PageCgroupUsed(pc)))
			continue;
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		if (unlikely(!PageLRU(page)))
1086 1087
			continue;

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		scan++;
1089 1090 1091
		ret = __isolate_lru_page(page, mode, file);
		switch (ret) {
		case 0:
1092
			list_move(&page->lru, dst);
1093
			mem_cgroup_del_lru(page);
1094
			nr_taken++;
1095 1096 1097 1098 1099 1100 1101
			break;
		case -EBUSY:
			/* we don't affect global LRU but rotate in our LRU */
			mem_cgroup_rotate_lru_list(page, page_lru(page));
			break;
		default:
			break;
1102 1103 1104 1105
		}
	}

	*scanned = scan;
1106 1107 1108 1109

	trace_mm_vmscan_memcg_isolate(0, nr_to_scan, scan, nr_taken,
				      0, 0, 0, mode);

1110 1111 1112
	return nr_taken;
}

1113 1114 1115
#define mem_cgroup_from_res_counter(counter, member)	\
	container_of(counter, struct mem_cgroup, member)

1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127
static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
{
	if (do_swap_account) {
		if (res_counter_check_under_limit(&mem->res) &&
			res_counter_check_under_limit(&mem->memsw))
			return true;
	} else
		if (res_counter_check_under_limit(&mem->res))
			return true;
	return false;
}

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static unsigned int get_swappiness(struct mem_cgroup *memcg)
{
	struct cgroup *cgrp = memcg->css.cgroup;
	unsigned int swappiness;

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

	spin_lock(&memcg->reclaim_param_lock);
	swappiness = memcg->swappiness;
	spin_unlock(&memcg->reclaim_param_lock);

	return swappiness;
}

1144 1145 1146
static void mem_cgroup_start_move(struct mem_cgroup *mem)
{
	int cpu;
1147 1148 1149 1150

	get_online_cpus();
	spin_lock(&mem->pcp_counter_lock);
	for_each_online_cpu(cpu)
1151
		per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1;
1152 1153 1154
	mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1;
	spin_unlock(&mem->pcp_counter_lock);
	put_online_cpus();
1155 1156 1157 1158 1159 1160 1161 1162 1163 1164

	synchronize_rcu();
}

static void mem_cgroup_end_move(struct mem_cgroup *mem)
{
	int cpu;

	if (!mem)
		return;
1165 1166 1167
	get_online_cpus();
	spin_lock(&mem->pcp_counter_lock);
	for_each_online_cpu(cpu)
1168
		per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1;
1169 1170 1171
	mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1;
	spin_unlock(&mem->pcp_counter_lock);
	put_online_cpus();
1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189
}
/*
 * 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".
 */

static bool mem_cgroup_stealed(struct mem_cgroup *mem)
{
	VM_BUG_ON(!rcu_read_lock_held());
	return this_cpu_read(mem->stat->count[MEM_CGROUP_ON_MOVE]) > 0;
}
1190 1191 1192

static bool mem_cgroup_under_move(struct mem_cgroup *mem)
{
1193 1194
	struct mem_cgroup *from;
	struct mem_cgroup *to;
1195
	bool ret = false;
1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210
	/*
	 * 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;
	if (from == mem || to == mem
	    || (mem->use_hierarchy && css_is_ancestor(&from->css, &mem->css))
	    || (mem->use_hierarchy && css_is_ancestor(&to->css,	&mem->css)))
		ret = true;
unlock:
	spin_unlock(&mc.lock);
1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229
	return ret;
}

static bool mem_cgroup_wait_acct_move(struct mem_cgroup *mem)
{
	if (mc.moving_task && current != mc.moving_task) {
		if (mem_cgroup_under_move(mem)) {
			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;
}

1230
/**
1231
 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249
 * @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;

1250
	if (!memcg || !p)
1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296
		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));
}

1297 1298 1299 1300 1301 1302 1303
/*
 * This function returns the number of memcg under hierarchy tree. Returns
 * 1(self count) if no children.
 */
static int mem_cgroup_count_children(struct mem_cgroup *mem)
{
	int num = 0;
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1304 1305 1306 1307
	struct mem_cgroup *iter;

	for_each_mem_cgroup_tree(iter, mem)
		num++;
1308 1309 1310
	return num;
}

D
David Rientjes 已提交
1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328
/*
 * Return the memory (and swap, if configured) limit for a memcg.
 */
u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
{
	u64 limit;
	u64 memsw;

	limit = res_counter_read_u64(&memcg->res, RES_LIMIT) +
			total_swap_pages;
	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);
}

1329
/*
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1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371
 * Visit the first child (need not be the first child as per the ordering
 * of the cgroup list, since we track last_scanned_child) of @mem and use
 * that to reclaim free pages from.
 */
static struct mem_cgroup *
mem_cgroup_select_victim(struct mem_cgroup *root_mem)
{
	struct mem_cgroup *ret = NULL;
	struct cgroup_subsys_state *css;
	int nextid, found;

	if (!root_mem->use_hierarchy) {
		css_get(&root_mem->css);
		ret = root_mem;
	}

	while (!ret) {
		rcu_read_lock();
		nextid = root_mem->last_scanned_child + 1;
		css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
				   &found);
		if (css && css_tryget(css))
			ret = container_of(css, struct mem_cgroup, css);

		rcu_read_unlock();
		/* Updates scanning parameter */
		spin_lock(&root_mem->reclaim_param_lock);
		if (!css) {
			/* this means start scan from ID:1 */
			root_mem->last_scanned_child = 0;
		} else
			root_mem->last_scanned_child = found;
		spin_unlock(&root_mem->reclaim_param_lock);
	}

	return ret;
}

/*
 * Scan the hierarchy if needed to reclaim memory. We remember the last child
 * we reclaimed from, so that we don't end up penalizing one child extensively
 * based on its position in the children list.
1372 1373
 *
 * root_mem is the original ancestor that we've been reclaim from.
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1374 1375 1376
 *
 * We give up and return to the caller when we visit root_mem twice.
 * (other groups can be removed while we're walking....)
1377 1378
 *
 * If shrink==true, for avoiding to free too much, this returns immedieately.
1379 1380
 */
static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
1381
						struct zone *zone,
1382 1383
						gfp_t gfp_mask,
						unsigned long reclaim_options)
1384
{
K
KAMEZAWA Hiroyuki 已提交
1385 1386 1387
	struct mem_cgroup *victim;
	int ret, total = 0;
	int loop = 0;
1388 1389
	bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
	bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
1390 1391
	bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
	unsigned long excess = mem_cgroup_get_excess(root_mem);
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1392

1393 1394 1395 1396
	/* If memsw_is_minimum==1, swap-out is of-no-use. */
	if (root_mem->memsw_is_minimum)
		noswap = true;

1397
	while (1) {
K
KAMEZAWA Hiroyuki 已提交
1398
		victim = mem_cgroup_select_victim(root_mem);
1399
		if (victim == root_mem) {
K
KAMEZAWA Hiroyuki 已提交
1400
			loop++;
1401 1402
			if (loop >= 1)
				drain_all_stock_async();
1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425
			if (loop >= 2) {
				/*
				 * If we have not been able to reclaim
				 * anything, it might because there are
				 * no reclaimable pages under this hierarchy
				 */
				if (!check_soft || !total) {
					css_put(&victim->css);
					break;
				}
				/*
				 * We want to do more targetted reclaim.
				 * 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) ||
					(loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) {
					css_put(&victim->css);
					break;
				}
			}
		}
1426
		if (!mem_cgroup_local_usage(victim)) {
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KAMEZAWA Hiroyuki 已提交
1427 1428
			/* this cgroup's local usage == 0 */
			css_put(&victim->css);
1429 1430
			continue;
		}
K
KAMEZAWA Hiroyuki 已提交
1431
		/* we use swappiness of local cgroup */
1432 1433
		if (check_soft)
			ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
1434
				noswap, get_swappiness(victim), zone);
1435 1436 1437
		else
			ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
						noswap, get_swappiness(victim));
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1438
		css_put(&victim->css);
1439 1440 1441 1442 1443 1444 1445
		/*
		 * At shrinking usage, we can't check we should stop here or
		 * reclaim more. It's depends on callers. last_scanned_child
		 * will work enough for keeping fairness under tree.
		 */
		if (shrink)
			return ret;
K
KAMEZAWA Hiroyuki 已提交
1446
		total += ret;
1447 1448 1449 1450
		if (check_soft) {
			if (res_counter_check_under_soft_limit(&root_mem->res))
				return total;
		} else if (mem_cgroup_check_under_limit(root_mem))
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1451
			return 1 + total;
1452
	}
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1453
	return total;
1454 1455
}

K
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1456 1457 1458 1459 1460 1461
/*
 * Check OOM-Killer is already running under our hierarchy.
 * If someone is running, return false.
 */
static bool mem_cgroup_oom_lock(struct mem_cgroup *mem)
{
K
KAMEZAWA Hiroyuki 已提交
1462 1463
	int x, lock_count = 0;
	struct mem_cgroup *iter;
1464

K
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1465 1466 1467 1468
	for_each_mem_cgroup_tree(iter, mem) {
		x = atomic_inc_return(&iter->oom_lock);
		lock_count = max(x, lock_count);
	}
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1469 1470 1471 1472

	if (lock_count == 1)
		return true;
	return false;
1473
}
1474

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1475
static int mem_cgroup_oom_unlock(struct mem_cgroup *mem)
1476
{
K
KAMEZAWA Hiroyuki 已提交
1477 1478
	struct mem_cgroup *iter;

K
KAMEZAWA Hiroyuki 已提交
1479 1480 1481 1482 1483
	/*
	 * 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.
	 */
K
KAMEZAWA Hiroyuki 已提交
1484 1485
	for_each_mem_cgroup_tree(iter, mem)
		atomic_add_unless(&iter->oom_lock, -1, 0);
1486 1487 1488
	return 0;
}

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1489 1490 1491 1492

static DEFINE_MUTEX(memcg_oom_mutex);
static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);

K
KAMEZAWA Hiroyuki 已提交
1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528
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)
{
	struct mem_cgroup *wake_mem = (struct mem_cgroup *)arg;
	struct oom_wait_info *oom_wait_info;

	oom_wait_info = container_of(wait, struct oom_wait_info, wait);

	if (oom_wait_info->mem == wake_mem)
		goto wakeup;
	/* if no hierarchy, no match */
	if (!oom_wait_info->mem->use_hierarchy || !wake_mem->use_hierarchy)
		return 0;
	/*
	 * 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.
	 */
	if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) &&
	    !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css))
		return 0;

wakeup:
	return autoremove_wake_function(wait, mode, sync, arg);
}

static void memcg_wakeup_oom(struct mem_cgroup *mem)
{
	/* for filtering, pass "mem" as argument. */
	__wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, mem);
}

1529 1530
static void memcg_oom_recover(struct mem_cgroup *mem)
{
1531
	if (mem && atomic_read(&mem->oom_lock))
1532 1533 1534
		memcg_wakeup_oom(mem);
}

K
KAMEZAWA Hiroyuki 已提交
1535 1536 1537 1538
/*
 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
 */
bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask)
1539
{
K
KAMEZAWA Hiroyuki 已提交
1540
	struct oom_wait_info owait;
1541
	bool locked, need_to_kill;
K
KAMEZAWA Hiroyuki 已提交
1542

K
KAMEZAWA Hiroyuki 已提交
1543 1544 1545 1546 1547
	owait.mem = mem;
	owait.wait.flags = 0;
	owait.wait.func = memcg_oom_wake_function;
	owait.wait.private = current;
	INIT_LIST_HEAD(&owait.wait.task_list);
1548
	need_to_kill = true;
K
KAMEZAWA Hiroyuki 已提交
1549 1550 1551 1552 1553 1554 1555 1556
	/* At first, try to OOM lock hierarchy under mem.*/
	mutex_lock(&memcg_oom_mutex);
	locked = mem_cgroup_oom_lock(mem);
	/*
	 * 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.
	 */
1557 1558 1559 1560
	prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
	if (!locked || mem->oom_kill_disable)
		need_to_kill = false;
	if (locked)
K
KAMEZAWA Hiroyuki 已提交
1561
		mem_cgroup_oom_notify(mem);
K
KAMEZAWA Hiroyuki 已提交
1562 1563
	mutex_unlock(&memcg_oom_mutex);

1564 1565
	if (need_to_kill) {
		finish_wait(&memcg_oom_waitq, &owait.wait);
K
KAMEZAWA Hiroyuki 已提交
1566
		mem_cgroup_out_of_memory(mem, mask);
1567
	} else {
K
KAMEZAWA Hiroyuki 已提交
1568
		schedule();
K
KAMEZAWA Hiroyuki 已提交
1569
		finish_wait(&memcg_oom_waitq, &owait.wait);
K
KAMEZAWA Hiroyuki 已提交
1570 1571 1572
	}
	mutex_lock(&memcg_oom_mutex);
	mem_cgroup_oom_unlock(mem);
K
KAMEZAWA Hiroyuki 已提交
1573
	memcg_wakeup_oom(mem);
K
KAMEZAWA Hiroyuki 已提交
1574 1575 1576 1577 1578 1579 1580
	mutex_unlock(&memcg_oom_mutex);

	if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current))
		return false;
	/* Give chance to dying process */
	schedule_timeout(1);
	return true;
1581 1582
}

1583 1584 1585
/*
 * Currently used to update mapped file statistics, but the routine can be
 * generalized to update other statistics as well.
1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604
 *
 * 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.
1605
 */
1606 1607

static void mem_cgroup_update_file_stat(struct page *page, int idx, int val)
1608 1609
{
	struct mem_cgroup *mem;
1610 1611
	struct page_cgroup *pc = lookup_page_cgroup(page);
	bool need_unlock = false;
1612 1613 1614 1615

	if (unlikely(!pc))
		return;

1616
	rcu_read_lock();
1617
	mem = pc->mem_cgroup;
1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628
	if (unlikely(!mem || !PageCgroupUsed(pc)))
		goto out;
	/* pc->mem_cgroup is unstable ? */
	if (unlikely(mem_cgroup_stealed(mem))) {
		/* take a lock against to access pc->mem_cgroup */
		lock_page_cgroup(pc);
		need_unlock = true;
		mem = pc->mem_cgroup;
		if (!mem || !PageCgroupUsed(pc))
			goto out;
	}
1629 1630 1631 1632 1633 1634 1635 1636

	this_cpu_add(mem->stat->count[idx], val);

	switch (idx) {
	case MEM_CGROUP_STAT_FILE_MAPPED:
		if (val > 0)
			SetPageCgroupFileMapped(pc);
		else if (!page_mapped(page))
1637
			ClearPageCgroupFileMapped(pc);
1638 1639 1640
		break;
	default:
		BUG();
1641
	}
1642

1643 1644 1645 1646 1647
out:
	if (unlikely(need_unlock))
		unlock_page_cgroup(pc);
	rcu_read_unlock();
	return;
1648
}
1649

1650 1651 1652 1653 1654
void mem_cgroup_update_file_mapped(struct page *page, int val)
{
	mem_cgroup_update_file_stat(page, MEM_CGROUP_STAT_FILE_MAPPED, val);
}

1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715
/*
 * size of first charge trial. "32" comes from vmscan.c's magic value.
 * TODO: maybe necessary to use big numbers in big irons.
 */
#define CHARGE_SIZE	(32 * PAGE_SIZE)
struct memcg_stock_pcp {
	struct mem_cgroup *cached; /* this never be root cgroup */
	int charge;
	struct work_struct work;
};
static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
static atomic_t memcg_drain_count;

/*
 * Try to consume stocked charge on this cpu. If success, PAGE_SIZE is consumed
 * 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.
 */
static bool consume_stock(struct mem_cgroup *mem)
{
	struct memcg_stock_pcp *stock;
	bool ret = true;

	stock = &get_cpu_var(memcg_stock);
	if (mem == stock->cached && stock->charge)
		stock->charge -= PAGE_SIZE;
	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;

	if (stock->charge) {
		res_counter_uncharge(&old->res, stock->charge);
		if (do_swap_account)
			res_counter_uncharge(&old->memsw, stock->charge);
	}
	stock->cached = NULL;
	stock->charge = 0;
}

/*
 * 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);
}

/*
 * Cache charges(val) which is from res_counter, to local per_cpu area.
1716
 * This will be consumed by consume_stock() function, later.
1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767
 */
static void refill_stock(struct mem_cgroup *mem, int val)
{
	struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);

	if (stock->cached != mem) { /* reset if necessary */
		drain_stock(stock);
		stock->cached = mem;
	}
	stock->charge += val;
	put_cpu_var(memcg_stock);
}

/*
 * 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.
 */
static void drain_all_stock_async(void)
{
	int cpu;
	/* This function is for scheduling "drain" in asynchronous way.
	 * The result of "drain" is not directly handled by callers. Then,
	 * if someone is calling drain, we don't have to call drain more.
	 * Anyway, WORK_STRUCT_PENDING check in queue_work_on() will catch if
	 * there is a race. We just do loose check here.
	 */
	if (atomic_read(&memcg_drain_count))
		return;
	/* Notify other cpus that system-wide "drain" is running */
	atomic_inc(&memcg_drain_count);
	get_online_cpus();
	for_each_online_cpu(cpu) {
		struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
		schedule_work_on(cpu, &stock->work);
	}
 	put_online_cpus();
	atomic_dec(&memcg_drain_count);
	/* We don't wait for flush_work */
}

/* This is a synchronous drain interface. */
static void drain_all_stock_sync(void)
{
	/* called when force_empty is called */
	atomic_inc(&memcg_drain_count);
	schedule_on_each_cpu(drain_local_stock);
	atomic_dec(&memcg_drain_count);
}

1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782
/*
 * This function drains percpu counter value from DEAD cpu and
 * move it to local cpu. Note that this function can be preempted.
 */
static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *mem, int cpu)
{
	int i;

	spin_lock(&mem->pcp_counter_lock);
	for (i = 0; i < MEM_CGROUP_STAT_DATA; i++) {
		s64 x = per_cpu(mem->stat->count[i], cpu);

		per_cpu(mem->stat->count[i], cpu) = 0;
		mem->nocpu_base.count[i] += x;
	}
1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793
	/* need to clear ON_MOVE value, works as a kind of lock. */
	per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) = 0;
	spin_unlock(&mem->pcp_counter_lock);
}

static void synchronize_mem_cgroup_on_move(struct mem_cgroup *mem, int cpu)
{
	int idx = MEM_CGROUP_ON_MOVE;

	spin_lock(&mem->pcp_counter_lock);
	per_cpu(mem->stat->count[idx], cpu) = mem->nocpu_base.count[idx];
1794 1795 1796 1797
	spin_unlock(&mem->pcp_counter_lock);
}

static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
1798 1799 1800 1801 1802
					unsigned long action,
					void *hcpu)
{
	int cpu = (unsigned long)hcpu;
	struct memcg_stock_pcp *stock;
1803
	struct mem_cgroup *iter;
1804

1805 1806 1807 1808 1809 1810
	if ((action == CPU_ONLINE)) {
		for_each_mem_cgroup_all(iter)
			synchronize_mem_cgroup_on_move(iter, cpu);
		return NOTIFY_OK;
	}

1811
	if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN)
1812
		return NOTIFY_OK;
1813 1814 1815 1816

	for_each_mem_cgroup_all(iter)
		mem_cgroup_drain_pcp_counter(iter, cpu);

1817 1818 1819 1820 1821
	stock = &per_cpu(memcg_stock, cpu);
	drain_stock(stock);
	return NOTIFY_OK;
}

1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888

/* 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 */
};

static int __mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask,
				int csize, bool oom_check)
{
	struct mem_cgroup *mem_over_limit;
	struct res_counter *fail_res;
	unsigned long flags = 0;
	int ret;

	ret = res_counter_charge(&mem->res, csize, &fail_res);

	if (likely(!ret)) {
		if (!do_swap_account)
			return CHARGE_OK;
		ret = res_counter_charge(&mem->memsw, csize, &fail_res);
		if (likely(!ret))
			return CHARGE_OK;

		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);

	if (csize > PAGE_SIZE) /* change csize and retry */
		return CHARGE_RETRY;

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

	ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
					gfp_mask, flags);
	/*
	 * try_to_free_mem_cgroup_pages() might not give us a full
	 * picture of reclaim. Some pages are reclaimed and might be
	 * moved to swap cache or just unmapped from the cgroup.
	 * Check the limit again to see if the reclaim reduced the
	 * current usage of the cgroup before giving up
	 */
	if (ret || mem_cgroup_check_under_limit(mem_over_limit))
		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;
}

1889 1890 1891
/*
 * Unlike exported interface, "oom" parameter is added. if oom==true,
 * oom-killer can be invoked.
1892
 */
1893
static int __mem_cgroup_try_charge(struct mm_struct *mm,
A
Andrea Arcangeli 已提交
1894 1895 1896
				   gfp_t gfp_mask,
				   struct mem_cgroup **memcg, bool oom,
				   int page_size)
1897
{
1898 1899 1900
	int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
	struct mem_cgroup *mem = NULL;
	int ret;
A
Andrea Arcangeli 已提交
1901
	int csize = max(CHARGE_SIZE, (unsigned long) page_size);
1902

K
KAMEZAWA Hiroyuki 已提交
1903 1904 1905 1906 1907 1908 1909 1910
	/*
	 * 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;
1911

1912
	/*
1913 1914
	 * We always charge the cgroup the mm_struct belongs to.
	 * The mm_struct's mem_cgroup changes on task migration if the
1915 1916 1917
	 * thread group leader migrates. It's possible that mm is not
	 * set, if so charge the init_mm (happens for pagecache usage).
	 */
K
KAMEZAWA Hiroyuki 已提交
1918 1919 1920 1921
	if (!*memcg && !mm)
		goto bypass;
again:
	if (*memcg) { /* css should be a valid one */
1922
		mem = *memcg;
K
KAMEZAWA Hiroyuki 已提交
1923 1924 1925
		VM_BUG_ON(css_is_removed(&mem->css));
		if (mem_cgroup_is_root(mem))
			goto done;
A
Andrea Arcangeli 已提交
1926
		if (page_size == PAGE_SIZE && consume_stock(mem))
K
KAMEZAWA Hiroyuki 已提交
1927
			goto done;
1928 1929
		css_get(&mem->css);
	} else {
K
KAMEZAWA Hiroyuki 已提交
1930
		struct task_struct *p;
1931

K
KAMEZAWA Hiroyuki 已提交
1932 1933 1934
		rcu_read_lock();
		p = rcu_dereference(mm->owner);
		/*
1935 1936 1937 1938 1939 1940 1941 1942
		 * Because we don't have task_lock(), "p" can exit.
		 * In that case, "mem" can point to root or p can be NULL with
		 * 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
1943 1944
		 */
		mem = mem_cgroup_from_task(p);
1945
		if (!mem || mem_cgroup_is_root(mem)) {
K
KAMEZAWA Hiroyuki 已提交
1946 1947 1948
			rcu_read_unlock();
			goto done;
		}
A
Andrea Arcangeli 已提交
1949
		if (page_size == PAGE_SIZE && consume_stock(mem)) {
K
KAMEZAWA Hiroyuki 已提交
1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967
			/*
			 * 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 */
		if (!css_tryget(&mem->css)) {
			rcu_read_unlock();
			goto again;
		}
		rcu_read_unlock();
	}
1968

1969 1970
	do {
		bool oom_check;
1971

1972
		/* If killed, bypass charge */
K
KAMEZAWA Hiroyuki 已提交
1973 1974
		if (fatal_signal_pending(current)) {
			css_put(&mem->css);
1975
			goto bypass;
K
KAMEZAWA Hiroyuki 已提交
1976
		}
1977

1978 1979 1980 1981
		oom_check = false;
		if (oom && !nr_oom_retries) {
			oom_check = true;
			nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
1982
		}
1983

1984
		ret = __mem_cgroup_do_charge(mem, gfp_mask, csize, oom_check);
1985

1986 1987 1988 1989
		switch (ret) {
		case CHARGE_OK:
			break;
		case CHARGE_RETRY: /* not in OOM situation but retry */
A
Andrea Arcangeli 已提交
1990
			csize = page_size;
K
KAMEZAWA Hiroyuki 已提交
1991 1992 1993
			css_put(&mem->css);
			mem = NULL;
			goto again;
1994
		case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
K
KAMEZAWA Hiroyuki 已提交
1995
			css_put(&mem->css);
1996 1997
			goto nomem;
		case CHARGE_NOMEM: /* OOM routine works */
K
KAMEZAWA Hiroyuki 已提交
1998 1999
			if (!oom) {
				css_put(&mem->css);
K
KAMEZAWA Hiroyuki 已提交
2000
				goto nomem;
K
KAMEZAWA Hiroyuki 已提交
2001
			}
2002 2003 2004 2005
			/* If oom, we never return -ENOMEM */
			nr_oom_retries--;
			break;
		case CHARGE_OOM_DIE: /* Killed by OOM Killer */
K
KAMEZAWA Hiroyuki 已提交
2006
			css_put(&mem->css);
K
KAMEZAWA Hiroyuki 已提交
2007
			goto bypass;
2008
		}
2009 2010
	} while (ret != CHARGE_OK);

A
Andrea Arcangeli 已提交
2011 2012
	if (csize > page_size)
		refill_stock(mem, csize - page_size);
K
KAMEZAWA Hiroyuki 已提交
2013
	css_put(&mem->css);
2014
done:
K
KAMEZAWA Hiroyuki 已提交
2015
	*memcg = mem;
2016 2017
	return 0;
nomem:
K
KAMEZAWA Hiroyuki 已提交
2018
	*memcg = NULL;
2019
	return -ENOMEM;
K
KAMEZAWA Hiroyuki 已提交
2020 2021 2022
bypass:
	*memcg = NULL;
	return 0;
2023
}
2024

2025 2026 2027 2028 2029
/*
 * 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().
 */
2030 2031
static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem,
							unsigned long count)
2032 2033
{
	if (!mem_cgroup_is_root(mem)) {
2034
		res_counter_uncharge(&mem->res, PAGE_SIZE * count);
2035
		if (do_swap_account)
2036
			res_counter_uncharge(&mem->memsw, PAGE_SIZE * count);
2037
	}
2038 2039
}

A
Andrea Arcangeli 已提交
2040 2041
static void mem_cgroup_cancel_charge(struct mem_cgroup *mem,
				     int page_size)
2042
{
A
Andrea Arcangeli 已提交
2043
	__mem_cgroup_cancel_charge(mem, page_size >> PAGE_SHIFT);
2044 2045
}

2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064
/*
 * 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);
}

2065
struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2066
{
2067
	struct mem_cgroup *mem = NULL;
2068
	struct page_cgroup *pc;
2069
	unsigned short id;
2070 2071
	swp_entry_t ent;

2072 2073 2074
	VM_BUG_ON(!PageLocked(page));

	pc = lookup_page_cgroup(page);
2075
	lock_page_cgroup(pc);
2076
	if (PageCgroupUsed(pc)) {
2077
		mem = pc->mem_cgroup;
2078 2079
		if (mem && !css_tryget(&mem->css))
			mem = NULL;
2080
	} else if (PageSwapCache(page)) {
2081
		ent.val = page_private(page);
2082 2083 2084 2085 2086 2087
		id = lookup_swap_cgroup(ent);
		rcu_read_lock();
		mem = mem_cgroup_lookup(id);
		if (mem && !css_tryget(&mem->css))
			mem = NULL;
		rcu_read_unlock();
2088
	}
2089
	unlock_page_cgroup(pc);
2090 2091 2092
	return mem;
}

2093
/*
2094
 * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be
2095 2096
 * USED state. If already USED, uncharge and return.
 */
2097 2098 2099
static void ____mem_cgroup_commit_charge(struct mem_cgroup *mem,
					 struct page_cgroup *pc,
					 enum charge_type ctype)
2100
{
2101
	pc->mem_cgroup = mem;
2102 2103 2104 2105 2106 2107 2108
	/*
	 * 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
2109
	smp_wmb();
2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122
	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;
	}
2123

K
KAMEZAWA Hiroyuki 已提交
2124
	mem_cgroup_charge_statistics(mem, pc, true);
2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151
}

static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
				       struct page_cgroup *pc,
				       enum charge_type ctype,
				       int page_size)
{
	int i;
	int count = page_size >> PAGE_SHIFT;

	/* try_charge() can return NULL to *memcg, taking care of it. */
	if (!mem)
		return;

	lock_page_cgroup(pc);
	if (unlikely(PageCgroupUsed(pc))) {
		unlock_page_cgroup(pc);
		mem_cgroup_cancel_charge(mem, page_size);
		return;
	}

	/*
	 * we don't need page_cgroup_lock about tail pages, becase they are not
	 * accessed by any other context at this point.
	 */
	for (i = 0; i < count; i++)
		____mem_cgroup_commit_charge(mem, pc + i, ctype);
2152 2153

	unlock_page_cgroup(pc);
2154 2155 2156 2157 2158
	/*
	 * "charge_statistics" updated event counter. Then, check it.
	 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
	 * if they exceeds softlimit.
	 */
2159
	memcg_check_events(mem, pc->page);
2160
}
2161

2162
/**
2163
 * __mem_cgroup_move_account - move account of the page
2164 2165 2166
 * @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.
2167
 * @uncharge: whether we should call uncharge and css_put against @from.
2168 2169
 *
 * The caller must confirm following.
K
KAMEZAWA Hiroyuki 已提交
2170
 * - page is not on LRU (isolate_page() is useful.)
2171
 * - the pc is locked, used, and ->mem_cgroup points to @from.
2172
 *
2173 2174 2175 2176
 * This function doesn't do "charge" nor css_get to new cgroup. It should be
 * done by a caller(__mem_cgroup_try_charge would be usefull). If @uncharge is
 * true, this function does "uncharge" from old cgroup, but it doesn't if
 * @uncharge is false, so a caller should do "uncharge".
2177 2178
 */

2179
static void __mem_cgroup_move_account(struct page_cgroup *pc,
2180
	struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge)
2181 2182
{
	VM_BUG_ON(from == to);
K
KAMEZAWA Hiroyuki 已提交
2183
	VM_BUG_ON(PageLRU(pc->page));
2184
	VM_BUG_ON(!page_is_cgroup_locked(pc));
2185 2186
	VM_BUG_ON(!PageCgroupUsed(pc));
	VM_BUG_ON(pc->mem_cgroup != from);
2187

2188
	if (PageCgroupFileMapped(pc)) {
2189 2190 2191 2192 2193
		/* 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();
2194
	}
2195 2196 2197
	mem_cgroup_charge_statistics(from, pc, false);
	if (uncharge)
		/* This is not "cancel", but cancel_charge does all we need. */
A
Andrea Arcangeli 已提交
2198
		mem_cgroup_cancel_charge(from, PAGE_SIZE);
2199

2200
	/* caller should have done css_get */
K
KAMEZAWA Hiroyuki 已提交
2201 2202
	pc->mem_cgroup = to;
	mem_cgroup_charge_statistics(to, pc, true);
2203 2204 2205
	/*
	 * We charges against "to" which may not have any tasks. Then, "to"
	 * can be under rmdir(). But in current implementation, caller of
2206 2207 2208
	 * this function is just force_empty() and move charge, so it's
	 * garanteed that "to" is never removed. So, we don't check rmdir
	 * status here.
2209
	 */
2210 2211 2212 2213 2214 2215 2216
}

/*
 * check whether the @pc is valid for moving account and call
 * __mem_cgroup_move_account()
 */
static int mem_cgroup_move_account(struct page_cgroup *pc,
2217
		struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge)
2218 2219 2220 2221
{
	int ret = -EINVAL;
	lock_page_cgroup(pc);
	if (PageCgroupUsed(pc) && pc->mem_cgroup == from) {
2222
		__mem_cgroup_move_account(pc, from, to, uncharge);
2223 2224 2225
		ret = 0;
	}
	unlock_page_cgroup(pc);
2226 2227 2228 2229 2230
	/*
	 * check events
	 */
	memcg_check_events(to, pc->page);
	memcg_check_events(from, pc->page);
2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241
	return ret;
}

/*
 * move charges to its parent.
 */

static int mem_cgroup_move_parent(struct page_cgroup *pc,
				  struct mem_cgroup *child,
				  gfp_t gfp_mask)
{
K
KAMEZAWA Hiroyuki 已提交
2242
	struct page *page = pc->page;
2243 2244 2245 2246 2247 2248 2249 2250 2251
	struct cgroup *cg = child->css.cgroup;
	struct cgroup *pcg = cg->parent;
	struct mem_cgroup *parent;
	int ret;

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

2252 2253 2254 2255 2256
	ret = -EBUSY;
	if (!get_page_unless_zero(page))
		goto out;
	if (isolate_lru_page(page))
		goto put;
K
KAMEZAWA Hiroyuki 已提交
2257

2258
	parent = mem_cgroup_from_cont(pcg);
A
Andrea Arcangeli 已提交
2259 2260
	ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false,
				      PAGE_SIZE);
2261
	if (ret || !parent)
2262
		goto put_back;
2263

2264 2265
	ret = mem_cgroup_move_account(pc, child, parent, true);
	if (ret)
A
Andrea Arcangeli 已提交
2266
		mem_cgroup_cancel_charge(parent, PAGE_SIZE);
2267
put_back:
K
KAMEZAWA Hiroyuki 已提交
2268
	putback_lru_page(page);
2269
put:
2270
	put_page(page);
2271
out:
2272 2273 2274
	return ret;
}

2275 2276 2277 2278 2279 2280 2281
/*
 * 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,
2282
				gfp_t gfp_mask, enum charge_type ctype)
2283
{
2284
	struct mem_cgroup *mem = NULL;
2285 2286
	struct page_cgroup *pc;
	int ret;
A
Andrea Arcangeli 已提交
2287 2288 2289 2290
	int page_size = PAGE_SIZE;

	if (PageTransHuge(page))
		page_size <<= compound_order(page);
2291 2292 2293 2294 2295 2296 2297

	pc = lookup_page_cgroup(page);
	/* can happen at boot */
	if (unlikely(!pc))
		return 0;
	prefetchw(pc);

A
Andrea Arcangeli 已提交
2298
	ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true, page_size);
2299
	if (ret || !mem)
2300 2301
		return ret;

A
Andrea Arcangeli 已提交
2302
	__mem_cgroup_commit_charge(mem, pc, ctype, page_size);
2303 2304 2305
	return 0;
}

2306 2307
int mem_cgroup_newpage_charge(struct page *page,
			      struct mm_struct *mm, gfp_t gfp_mask)
2308
{
2309
	if (mem_cgroup_disabled())
2310
		return 0;
2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321
	/*
	 * If already mapped, we don't have to account.
	 * If page cache, page->mapping has address_space.
	 * But page->mapping may have out-of-use anon_vma pointer,
	 * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
	 * is NULL.
  	 */
	if (page_mapped(page) || (page->mapping && !PageAnon(page)))
		return 0;
	if (unlikely(!mm))
		mm = &init_mm;
2322
	return mem_cgroup_charge_common(page, mm, gfp_mask,
2323
				MEM_CGROUP_CHARGE_TYPE_MAPPED);
2324 2325
}

D
Daisuke Nishimura 已提交
2326 2327 2328 2329
static void
__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
					enum charge_type ctype);

2330 2331
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
				gfp_t gfp_mask)
2332
{
2333 2334
	int ret;

2335
	if (mem_cgroup_disabled())
2336
		return 0;
2337 2338
	if (PageCompound(page))
		return 0;
2339 2340 2341 2342 2343 2344 2345 2346
	/*
	 * Corner case handling. This is called from add_to_page_cache()
	 * in usual. But some FS (shmem) precharges this page before calling it
	 * and call add_to_page_cache() with GFP_NOWAIT.
	 *
	 * For GFP_NOWAIT case, the page may be pre-charged before calling
	 * add_to_page_cache(). (See shmem.c) check it here and avoid to call
	 * charge twice. (It works but has to pay a bit larger cost.)
2347 2348
	 * And when the page is SwapCache, it should take swap information
	 * into account. This is under lock_page() now.
2349 2350 2351 2352
	 */
	if (!(gfp_mask & __GFP_WAIT)) {
		struct page_cgroup *pc;

2353 2354 2355 2356 2357 2358
		pc = lookup_page_cgroup(page);
		if (!pc)
			return 0;
		lock_page_cgroup(pc);
		if (PageCgroupUsed(pc)) {
			unlock_page_cgroup(pc);
2359 2360
			return 0;
		}
2361
		unlock_page_cgroup(pc);
2362 2363
	}

2364
	if (unlikely(!mm))
2365
		mm = &init_mm;
2366

2367 2368
	if (page_is_file_cache(page))
		return mem_cgroup_charge_common(page, mm, gfp_mask,
2369
				MEM_CGROUP_CHARGE_TYPE_CACHE);
2370

D
Daisuke Nishimura 已提交
2371 2372
	/* shmem */
	if (PageSwapCache(page)) {
2373 2374
		struct mem_cgroup *mem = NULL;

D
Daisuke Nishimura 已提交
2375 2376 2377 2378 2379 2380
		ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
		if (!ret)
			__mem_cgroup_commit_charge_swapin(page, mem,
					MEM_CGROUP_CHARGE_TYPE_SHMEM);
	} else
		ret = mem_cgroup_charge_common(page, mm, gfp_mask,
2381
					MEM_CGROUP_CHARGE_TYPE_SHMEM);
2382 2383

	return ret;
2384 2385
}

2386 2387 2388
/*
 * While swap-in, try_charge -> commit or cancel, the page is locked.
 * And when try_charge() successfully returns, one refcnt to memcg without
2389
 * struct page_cgroup is acquired. This refcnt will be consumed by
2390 2391
 * "commit()" or removed by "cancel()"
 */
2392 2393 2394 2395 2396
int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
				 struct page *page,
				 gfp_t mask, struct mem_cgroup **ptr)
{
	struct mem_cgroup *mem;
2397
	int ret;
2398

2399
	if (mem_cgroup_disabled())
2400 2401 2402 2403 2404 2405
		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
2406 2407 2408
	 * 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.
2409 2410
	 */
	if (!PageSwapCache(page))
H
Hugh Dickins 已提交
2411
		goto charge_cur_mm;
2412
	mem = try_get_mem_cgroup_from_page(page);
2413 2414
	if (!mem)
		goto charge_cur_mm;
2415
	*ptr = mem;
A
Andrea Arcangeli 已提交
2416
	ret = __mem_cgroup_try_charge(NULL, mask, ptr, true, PAGE_SIZE);
2417 2418
	css_put(&mem->css);
	return ret;
2419 2420 2421
charge_cur_mm:
	if (unlikely(!mm))
		mm = &init_mm;
A
Andrea Arcangeli 已提交
2422
	return __mem_cgroup_try_charge(mm, mask, ptr, true, PAGE_SIZE);
2423 2424
}

D
Daisuke Nishimura 已提交
2425 2426 2427
static void
__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
					enum charge_type ctype)
2428 2429 2430
{
	struct page_cgroup *pc;

2431
	if (mem_cgroup_disabled())
2432 2433 2434
		return;
	if (!ptr)
		return;
2435
	cgroup_exclude_rmdir(&ptr->css);
2436
	pc = lookup_page_cgroup(page);
2437
	mem_cgroup_lru_del_before_commit_swapcache(page);
A
Andrea Arcangeli 已提交
2438
	__mem_cgroup_commit_charge(ptr, pc, ctype, PAGE_SIZE);
2439
	mem_cgroup_lru_add_after_commit_swapcache(page);
2440 2441 2442
	/*
	 * Now swap is on-memory. This means this page may be
	 * counted both as mem and swap....double count.
2443 2444 2445
	 * 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.
2446
	 */
2447
	if (do_swap_account && PageSwapCache(page)) {
2448
		swp_entry_t ent = {.val = page_private(page)};
2449
		unsigned short id;
2450
		struct mem_cgroup *memcg;
2451 2452 2453 2454

		id = swap_cgroup_record(ent, 0);
		rcu_read_lock();
		memcg = mem_cgroup_lookup(id);
2455
		if (memcg) {
2456 2457 2458 2459
			/*
			 * This recorded memcg can be obsolete one. So, avoid
			 * calling css_tryget
			 */
2460
			if (!mem_cgroup_is_root(memcg))
2461
				res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2462
			mem_cgroup_swap_statistics(memcg, false);
2463 2464
			mem_cgroup_put(memcg);
		}
2465
		rcu_read_unlock();
2466
	}
2467 2468 2469 2470 2471 2472
	/*
	 * 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.
	 */
	cgroup_release_and_wakeup_rmdir(&ptr->css);
2473 2474
}

D
Daisuke Nishimura 已提交
2475 2476 2477 2478 2479 2480
void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
{
	__mem_cgroup_commit_charge_swapin(page, ptr,
					MEM_CGROUP_CHARGE_TYPE_MAPPED);
}

2481 2482
void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
{
2483
	if (mem_cgroup_disabled())
2484 2485 2486
		return;
	if (!mem)
		return;
A
Andrea Arcangeli 已提交
2487
	mem_cgroup_cancel_charge(mem, PAGE_SIZE);
2488 2489
}

2490
static void
A
Andrea Arcangeli 已提交
2491 2492
__do_uncharge(struct mem_cgroup *mem, const enum charge_type ctype,
	      int page_size)
2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507
{
	struct memcg_batch_info *batch = NULL;
	bool uncharge_memsw = true;
	/* 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)
		batch->memcg = mem;
2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518
	/*
	 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
	 * In those cases, all pages freed continously can be expected to be in
	 * 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;

A
Andrea Arcangeli 已提交
2519 2520 2521
	if (page_size != PAGE_SIZE)
		goto direct_uncharge;

2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534
	/*
	 * 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.
	 */
	if (batch->memcg != mem)
		goto direct_uncharge;
	/* remember freed charge and uncharge it later */
	batch->bytes += PAGE_SIZE;
	if (uncharge_memsw)
		batch->memsw_bytes += PAGE_SIZE;
	return;
direct_uncharge:
A
Andrea Arcangeli 已提交
2535
	res_counter_uncharge(&mem->res, page_size);
2536
	if (uncharge_memsw)
A
Andrea Arcangeli 已提交
2537
		res_counter_uncharge(&mem->memsw, page_size);
2538 2539
	if (unlikely(batch->memcg != mem))
		memcg_oom_recover(mem);
2540 2541
	return;
}
2542

2543
/*
2544
 * uncharge if !page_mapped(page)
2545
 */
2546
static struct mem_cgroup *
2547
__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
2548
{
2549 2550
	int i;
	int count;
H
Hugh Dickins 已提交
2551
	struct page_cgroup *pc;
2552
	struct mem_cgroup *mem = NULL;
A
Andrea Arcangeli 已提交
2553
	int page_size = PAGE_SIZE;
2554

2555
	if (mem_cgroup_disabled())
2556
		return NULL;
2557

K
KAMEZAWA Hiroyuki 已提交
2558
	if (PageSwapCache(page))
2559
		return NULL;
K
KAMEZAWA Hiroyuki 已提交
2560

A
Andrea Arcangeli 已提交
2561 2562 2563
	if (PageTransHuge(page))
		page_size <<= compound_order(page);

2564
	count = page_size >> PAGE_SHIFT;
2565
	/*
2566
	 * Check if our page_cgroup is valid
2567
	 */
2568 2569
	pc = lookup_page_cgroup(page);
	if (unlikely(!pc || !PageCgroupUsed(pc)))
2570
		return NULL;
2571

2572
	lock_page_cgroup(pc);
K
KAMEZAWA Hiroyuki 已提交
2573

2574 2575
	mem = pc->mem_cgroup;

K
KAMEZAWA Hiroyuki 已提交
2576 2577 2578 2579 2580
	if (!PageCgroupUsed(pc))
		goto unlock_out;

	switch (ctype) {
	case MEM_CGROUP_CHARGE_TYPE_MAPPED:
K
KAMEZAWA Hiroyuki 已提交
2581
	case MEM_CGROUP_CHARGE_TYPE_DROP:
2582 2583
		/* See mem_cgroup_prepare_migration() */
		if (page_mapped(page) || PageCgroupMigration(pc))
K
KAMEZAWA Hiroyuki 已提交
2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594
			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;
2595
	}
K
KAMEZAWA Hiroyuki 已提交
2596

2597 2598
	for (i = 0; i < count; i++)
		mem_cgroup_charge_statistics(mem, pc + i, false);
K
KAMEZAWA Hiroyuki 已提交
2599

2600
	ClearPageCgroupUsed(pc);
2601 2602 2603 2604 2605 2606
	/*
	 * 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.
	 */
2607

2608
	unlock_page_cgroup(pc);
K
KAMEZAWA Hiroyuki 已提交
2609 2610 2611 2612
	/*
	 * even after unlock, we have mem->res.usage here and this memcg
	 * will never be freed.
	 */
2613
	memcg_check_events(mem, page);
K
KAMEZAWA Hiroyuki 已提交
2614 2615 2616 2617 2618
	if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
		mem_cgroup_swap_statistics(mem, true);
		mem_cgroup_get(mem);
	}
	if (!mem_cgroup_is_root(mem))
A
Andrea Arcangeli 已提交
2619
		__do_uncharge(mem, ctype, page_size);
2620

2621
	return mem;
K
KAMEZAWA Hiroyuki 已提交
2622 2623 2624

unlock_out:
	unlock_page_cgroup(pc);
2625
	return NULL;
2626 2627
}

2628 2629
void mem_cgroup_uncharge_page(struct page *page)
{
2630 2631 2632 2633 2634
	/* early check. */
	if (page_mapped(page))
		return;
	if (page->mapping && !PageAnon(page))
		return;
2635 2636 2637 2638 2639 2640
	__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));
2641
	VM_BUG_ON(page->mapping);
2642 2643 2644
	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
}

2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684
/*
 * 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;
		current->memcg_batch.bytes = 0;
		current->memcg_batch.memsw_bytes = 0;
	}
}

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.
	 */
	if (batch->bytes)
		res_counter_uncharge(&batch->memcg->res, batch->bytes);
	if (batch->memsw_bytes)
		res_counter_uncharge(&batch->memcg->memsw, batch->memsw_bytes);
2685
	memcg_oom_recover(batch->memcg);
2686 2687 2688 2689
	/* forget this pointer (for sanity check) */
	batch->memcg = NULL;
}

2690
#ifdef CONFIG_SWAP
2691
/*
2692
 * called after __delete_from_swap_cache() and drop "page" account.
2693 2694
 * memcg information is recorded to swap_cgroup of "ent"
 */
K
KAMEZAWA Hiroyuki 已提交
2695 2696
void
mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
2697 2698
{
	struct mem_cgroup *memcg;
K
KAMEZAWA Hiroyuki 已提交
2699 2700 2701 2702 2703 2704
	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);
2705

K
KAMEZAWA Hiroyuki 已提交
2706 2707 2708 2709 2710
	/*
	 * record memcg information,  if swapout && memcg != NULL,
	 * mem_cgroup_get() was called in uncharge().
	 */
	if (do_swap_account && swapout && memcg)
2711
		swap_cgroup_record(ent, css_id(&memcg->css));
2712
}
2713
#endif
2714 2715 2716 2717 2718 2719 2720

#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
2721
{
2722
	struct mem_cgroup *memcg;
2723
	unsigned short id;
2724 2725 2726 2727

	if (!do_swap_account)
		return;

2728 2729 2730
	id = swap_cgroup_record(ent, 0);
	rcu_read_lock();
	memcg = mem_cgroup_lookup(id);
2731
	if (memcg) {
2732 2733 2734 2735
		/*
		 * We uncharge this because swap is freed.
		 * This memcg can be obsolete one. We avoid calling css_tryget
		 */
2736
		if (!mem_cgroup_is_root(memcg))
2737
			res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2738
		mem_cgroup_swap_statistics(memcg, false);
2739 2740
		mem_cgroup_put(memcg);
	}
2741
	rcu_read_unlock();
K
KAMEZAWA Hiroyuki 已提交
2742
}
2743 2744 2745 2746 2747 2748

/**
 * 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
2749
 * @need_fixup: whether we should fixup res_counters and refcounts.
2750 2751 2752 2753 2754 2755 2756 2757 2758 2759
 *
 * 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,
2760
		struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2761 2762 2763 2764 2765 2766 2767 2768
{
	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);
2769
		mem_cgroup_swap_statistics(to, true);
2770
		/*
2771 2772 2773 2774 2775 2776
		 * 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.
2777 2778
		 */
		mem_cgroup_get(to);
2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789
		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);
		}
2790 2791 2792 2793 2794 2795
		return 0;
	}
	return -EINVAL;
}
#else
static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
2796
		struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2797 2798 2799
{
	return -EINVAL;
}
2800
#endif
K
KAMEZAWA Hiroyuki 已提交
2801

2802
/*
2803 2804
 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
 * page belongs to.
2805
 */
2806 2807
int mem_cgroup_prepare_migration(struct page *page,
	struct page *newpage, struct mem_cgroup **ptr)
2808 2809
{
	struct page_cgroup *pc;
2810
	struct mem_cgroup *mem = NULL;
2811
	enum charge_type ctype;
2812
	int ret = 0;
2813

A
Andrea Arcangeli 已提交
2814
	VM_BUG_ON(PageTransHuge(page));
2815
	if (mem_cgroup_disabled())
2816 2817
		return 0;

2818 2819 2820
	pc = lookup_page_cgroup(page);
	lock_page_cgroup(pc);
	if (PageCgroupUsed(pc)) {
2821 2822
		mem = pc->mem_cgroup;
		css_get(&mem->css);
2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853
		/*
		 * 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);
2854
	}
2855
	unlock_page_cgroup(pc);
2856 2857 2858 2859 2860 2861
	/*
	 * If the page is not charged at this point,
	 * we return here.
	 */
	if (!mem)
		return 0;
2862

A
Andrea Arcangeli 已提交
2863
	*ptr = mem;
A
Andrea Arcangeli 已提交
2864
	ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, ptr, false, PAGE_SIZE);
2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876
	css_put(&mem->css);/* drop extra refcnt */
	if (ret || *ptr == NULL) {
		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);
		}
		return -ENOMEM;
2877
	}
2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890
	/*
	 * 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;
A
Andrea Arcangeli 已提交
2891
	__mem_cgroup_commit_charge(mem, pc, ctype, PAGE_SIZE);
2892
	return ret;
2893
}
2894

2895
/* remove redundant charge if migration failed*/
2896
void mem_cgroup_end_migration(struct mem_cgroup *mem,
2897
	struct page *oldpage, struct page *newpage)
2898
{
2899
	struct page *used, *unused;
2900 2901 2902 2903
	struct page_cgroup *pc;

	if (!mem)
		return;
2904
	/* blocks rmdir() */
2905
	cgroup_exclude_rmdir(&mem->css);
2906 2907
	/* at migration success, oldpage->mapping is NULL. */
	if (oldpage->mapping) {
2908 2909
		used = oldpage;
		unused = newpage;
2910
	} else {
2911
		used = newpage;
2912 2913
		unused = oldpage;
	}
2914
	/*
2915 2916 2917
	 * 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.
2918
	 */
2919 2920 2921 2922
	pc = lookup_page_cgroup(oldpage);
	lock_page_cgroup(pc);
	ClearPageCgroupMigration(pc);
	unlock_page_cgroup(pc);
2923

2924 2925
	__mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);

2926
	/*
2927 2928 2929 2930 2931 2932
	 * 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)
2933
	 */
2934 2935
	if (PageAnon(used))
		mem_cgroup_uncharge_page(used);
2936
	/*
2937 2938
	 * At migration, we may charge account against cgroup which has no
	 * tasks.
2939 2940 2941 2942
	 * 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.
	 */
	cgroup_release_and_wakeup_rmdir(&mem->css);
2943
}
2944

2945
/*
2946 2947 2948 2949 2950 2951
 * A call to try to shrink memory usage on charge failure at shmem's swapin.
 * Calling hierarchical_reclaim is not enough because we should update
 * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM.
 * Moreover considering hierarchy, we should reclaim from the mem_over_limit,
 * not from the memcg which this page would be charged to.
 * try_charge_swapin does all of these works properly.
2952
 */
2953
int mem_cgroup_shmem_charge_fallback(struct page *page,
2954 2955
			    struct mm_struct *mm,
			    gfp_t gfp_mask)
2956
{
2957
	struct mem_cgroup *mem = NULL;
2958
	int ret;
2959

2960
	if (mem_cgroup_disabled())
2961
		return 0;
2962

2963 2964 2965
	ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
	if (!ret)
		mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
2966

2967
	return ret;
2968 2969
}

2970 2971
static DEFINE_MUTEX(set_limit_mutex);

2972
static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
2973
				unsigned long long val)
2974
{
2975
	int retry_count;
2976
	u64 memswlimit, memlimit;
2977
	int ret = 0;
2978 2979
	int children = mem_cgroup_count_children(memcg);
	u64 curusage, oldusage;
2980
	int enlarge;
2981 2982 2983 2984 2985 2986 2987 2988 2989

	/*
	 * 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);
2990

2991
	enlarge = 0;
2992
	while (retry_count) {
2993 2994 2995 2996
		if (signal_pending(current)) {
			ret = -EINTR;
			break;
		}
2997 2998 2999 3000 3001 3002 3003 3004 3005 3006
		/*
		 * Rather than hide all in some function, I do this in
		 * open coded manner. You see what this really does.
		 * We have to guarantee mem->res.limit < mem->memsw.limit.
		 */
		mutex_lock(&set_limit_mutex);
		memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
		if (memswlimit < val) {
			ret = -EINVAL;
			mutex_unlock(&set_limit_mutex);
3007 3008
			break;
		}
3009 3010 3011 3012 3013

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

3014
		ret = res_counter_set_limit(&memcg->res, val);
3015 3016 3017 3018 3019 3020
		if (!ret) {
			if (memswlimit == val)
				memcg->memsw_is_minimum = true;
			else
				memcg->memsw_is_minimum = false;
		}
3021 3022 3023 3024 3025
		mutex_unlock(&set_limit_mutex);

		if (!ret)
			break;

3026
		mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3027
						MEM_CGROUP_RECLAIM_SHRINK);
3028 3029 3030 3031 3032 3033
		curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
		/* Usage is reduced ? */
  		if (curusage >= oldusage)
			retry_count--;
		else
			oldusage = curusage;
3034
	}
3035 3036
	if (!ret && enlarge)
		memcg_oom_recover(memcg);
3037

3038 3039 3040
	return ret;
}

L
Li Zefan 已提交
3041 3042
static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
					unsigned long long val)
3043
{
3044
	int retry_count;
3045
	u64 memlimit, memswlimit, oldusage, curusage;
3046 3047
	int children = mem_cgroup_count_children(memcg);
	int ret = -EBUSY;
3048
	int enlarge = 0;
3049

3050 3051 3052
	/* see mem_cgroup_resize_res_limit */
 	retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
	oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069
	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.
		 * We have to guarantee mem->res.limit < mem->memsw.limit.
		 */
		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;
		}
3070 3071 3072
		memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
		if (memswlimit < val)
			enlarge = 1;
3073
		ret = res_counter_set_limit(&memcg->memsw, val);
3074 3075 3076 3077 3078 3079
		if (!ret) {
			if (memlimit == val)
				memcg->memsw_is_minimum = true;
			else
				memcg->memsw_is_minimum = false;
		}
3080 3081 3082 3083 3084
		mutex_unlock(&set_limit_mutex);

		if (!ret)
			break;

3085
		mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3086 3087
						MEM_CGROUP_RECLAIM_NOSWAP |
						MEM_CGROUP_RECLAIM_SHRINK);
3088
		curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3089
		/* Usage is reduced ? */
3090
		if (curusage >= oldusage)
3091
			retry_count--;
3092 3093
		else
			oldusage = curusage;
3094
	}
3095 3096
	if (!ret && enlarge)
		memcg_oom_recover(memcg);
3097 3098 3099
	return ret;
}

3100
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3101
					    gfp_t gfp_mask)
3102 3103 3104 3105 3106 3107
{
	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;
3108
	unsigned long long excess;
3109 3110 3111 3112

	if (order > 0)
		return 0;

3113
	mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160
	/*
	 * 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;

		reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone,
						gfp_mask,
						MEM_CGROUP_RECLAIM_SOFT);
		nr_reclaimed += reclaimed;
		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);
				if (next_mz == mz) {
					css_put(&next_mz->mem->css);
					next_mz = NULL;
				} else /* next_mz == NULL or other memcg */
					break;
			} while (1);
		}
		__mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
3161
		excess = res_counter_soft_limit_excess(&mz->mem->res);
3162 3163 3164 3165 3166 3167 3168 3169
		/*
		 * 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.
		 */
3170 3171
		/* If excess == 0, no tree ops */
		__mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess);
3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189
		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;
}

3190 3191 3192 3193
/*
 * This routine traverse page_cgroup in given list and drop them all.
 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
 */
3194
static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
K
KAMEZAWA Hiroyuki 已提交
3195
				int node, int zid, enum lru_list lru)
3196
{
K
KAMEZAWA Hiroyuki 已提交
3197 3198
	struct zone *zone;
	struct mem_cgroup_per_zone *mz;
3199
	struct page_cgroup *pc, *busy;
K
KAMEZAWA Hiroyuki 已提交
3200
	unsigned long flags, loop;
3201
	struct list_head *list;
3202
	int ret = 0;
3203

K
KAMEZAWA Hiroyuki 已提交
3204 3205
	zone = &NODE_DATA(node)->node_zones[zid];
	mz = mem_cgroup_zoneinfo(mem, node, zid);
3206
	list = &mz->lists[lru];
3207

3208 3209 3210 3211 3212 3213
	loop = MEM_CGROUP_ZSTAT(mz, lru);
	/* give some margin against EBUSY etc...*/
	loop += 256;
	busy = NULL;
	while (loop--) {
		ret = 0;
K
KAMEZAWA Hiroyuki 已提交
3214
		spin_lock_irqsave(&zone->lru_lock, flags);
3215
		if (list_empty(list)) {
K
KAMEZAWA Hiroyuki 已提交
3216
			spin_unlock_irqrestore(&zone->lru_lock, flags);
3217
			break;
3218 3219 3220 3221
		}
		pc = list_entry(list->prev, struct page_cgroup, lru);
		if (busy == pc) {
			list_move(&pc->lru, list);
3222
			busy = NULL;
K
KAMEZAWA Hiroyuki 已提交
3223
			spin_unlock_irqrestore(&zone->lru_lock, flags);
3224 3225
			continue;
		}
K
KAMEZAWA Hiroyuki 已提交
3226
		spin_unlock_irqrestore(&zone->lru_lock, flags);
3227

K
KAMEZAWA Hiroyuki 已提交
3228
		ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL);
3229
		if (ret == -ENOMEM)
3230
			break;
3231 3232 3233 3234 3235 3236 3237

		if (ret == -EBUSY || ret == -EINVAL) {
			/* found lock contention or "pc" is obsolete. */
			busy = pc;
			cond_resched();
		} else
			busy = NULL;
3238
	}
K
KAMEZAWA Hiroyuki 已提交
3239

3240 3241 3242
	if (!ret && !list_empty(list))
		return -EBUSY;
	return ret;
3243 3244 3245 3246 3247 3248
}

/*
 * make mem_cgroup's charge to be 0 if there is no task.
 * This enables deleting this mem_cgroup.
 */
3249
static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
3250
{
3251 3252 3253
	int ret;
	int node, zid, shrink;
	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3254
	struct cgroup *cgrp = mem->css.cgroup;
3255

3256
	css_get(&mem->css);
3257 3258

	shrink = 0;
3259 3260 3261
	/* should free all ? */
	if (free_all)
		goto try_to_free;
3262
move_account:
3263
	do {
3264
		ret = -EBUSY;
3265 3266 3267 3268
		if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
			goto out;
		ret = -EINTR;
		if (signal_pending(current))
3269
			goto out;
3270 3271
		/* This is for making all *used* pages to be on LRU. */
		lru_add_drain_all();
3272
		drain_all_stock_sync();
3273
		ret = 0;
3274
		mem_cgroup_start_move(mem);
3275
		for_each_node_state(node, N_HIGH_MEMORY) {
3276
			for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
3277
				enum lru_list l;
3278 3279
				for_each_lru(l) {
					ret = mem_cgroup_force_empty_list(mem,
K
KAMEZAWA Hiroyuki 已提交
3280
							node, zid, l);
3281 3282 3283
					if (ret)
						break;
				}
3284
			}
3285 3286 3287
			if (ret)
				break;
		}
3288
		mem_cgroup_end_move(mem);
3289
		memcg_oom_recover(mem);
3290 3291 3292
		/* it seems parent cgroup doesn't have enough mem */
		if (ret == -ENOMEM)
			goto try_to_free;
3293
		cond_resched();
3294 3295
	/* "ret" should also be checked to ensure all lists are empty. */
	} while (mem->res.usage > 0 || ret);
3296 3297 3298
out:
	css_put(&mem->css);
	return ret;
3299 3300

try_to_free:
3301 3302
	/* returns EBUSY if there is a task or if we come here twice. */
	if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
3303 3304 3305
		ret = -EBUSY;
		goto out;
	}
3306 3307
	/* we call try-to-free pages for make this cgroup empty */
	lru_add_drain_all();
3308 3309 3310 3311
	/* try to free all pages in this cgroup */
	shrink = 1;
	while (nr_retries && mem->res.usage > 0) {
		int progress;
3312 3313 3314 3315 3316

		if (signal_pending(current)) {
			ret = -EINTR;
			goto out;
		}
K
KOSAKI Motohiro 已提交
3317 3318
		progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
						false, get_swappiness(mem));
3319
		if (!progress) {
3320
			nr_retries--;
3321
			/* maybe some writeback is necessary */
3322
			congestion_wait(BLK_RW_ASYNC, HZ/10);
3323
		}
3324 3325

	}
K
KAMEZAWA Hiroyuki 已提交
3326
	lru_add_drain();
3327
	/* try move_account...there may be some *locked* pages. */
3328
	goto move_account;
3329 3330
}

3331 3332 3333 3334 3335 3336
int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
{
	return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
}


3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 3349 3350 3351 3352 3353 3354
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;
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
	struct cgroup *parent = cont->parent;
	struct mem_cgroup *parent_mem = NULL;

	if (parent)
		parent_mem = mem_cgroup_from_cont(parent);

	cgroup_lock();
	/*
3355
	 * If parent's use_hierarchy is set, we can't make any modifications
3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374
	 * 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.
	 */
	if ((!parent_mem || !parent_mem->use_hierarchy) &&
				(val == 1 || val == 0)) {
		if (list_empty(&cont->children))
			mem->use_hierarchy = val;
		else
			retval = -EBUSY;
	} else
		retval = -EINVAL;
	cgroup_unlock();

	return retval;
}

3375

K
KAMEZAWA Hiroyuki 已提交
3376 3377
static u64 mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem,
				enum mem_cgroup_stat_index idx)
3378
{
K
KAMEZAWA Hiroyuki 已提交
3379 3380
	struct mem_cgroup *iter;
	s64 val = 0;
3381

K
KAMEZAWA Hiroyuki 已提交
3382 3383 3384 3385 3386 3387 3388
	/* each per cpu's value can be minus.Then, use s64 */
	for_each_mem_cgroup_tree(iter, mem)
		val += mem_cgroup_read_stat(iter, idx);

	if (val < 0) /* race ? */
		val = 0;
	return val;
3389 3390
}

3391 3392
static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap)
{
K
KAMEZAWA Hiroyuki 已提交
3393
	u64 val;
3394 3395 3396 3397 3398 3399 3400 3401

	if (!mem_cgroup_is_root(mem)) {
		if (!swap)
			return res_counter_read_u64(&mem->res, RES_USAGE);
		else
			return res_counter_read_u64(&mem->memsw, RES_USAGE);
	}

K
KAMEZAWA Hiroyuki 已提交
3402 3403
	val = mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_CACHE);
	val += mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_RSS);
3404

K
KAMEZAWA Hiroyuki 已提交
3405 3406 3407
	if (swap)
		val += mem_cgroup_get_recursive_idx_stat(mem,
				MEM_CGROUP_STAT_SWAPOUT);
3408 3409 3410 3411

	return val << PAGE_SHIFT;
}

3412
static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
B
Balbir Singh 已提交
3413
{
3414
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3415
	u64 val;
3416 3417 3418 3419 3420 3421
	int type, name;

	type = MEMFILE_TYPE(cft->private);
	name = MEMFILE_ATTR(cft->private);
	switch (type) {
	case _MEM:
3422 3423 3424
		if (name == RES_USAGE)
			val = mem_cgroup_usage(mem, false);
		else
3425
			val = res_counter_read_u64(&mem->res, name);
3426 3427
		break;
	case _MEMSWAP:
3428 3429 3430
		if (name == RES_USAGE)
			val = mem_cgroup_usage(mem, true);
		else
3431
			val = res_counter_read_u64(&mem->memsw, name);
3432 3433 3434 3435 3436 3437
		break;
	default:
		BUG();
		break;
	}
	return val;
B
Balbir Singh 已提交
3438
}
3439 3440 3441 3442
/*
 * The user of this function is...
 * RES_LIMIT.
 */
3443 3444
static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
			    const char *buffer)
B
Balbir Singh 已提交
3445
{
3446
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3447
	int type, name;
3448 3449 3450
	unsigned long long val;
	int ret;

3451 3452 3453
	type = MEMFILE_TYPE(cft->private);
	name = MEMFILE_ATTR(cft->private);
	switch (name) {
3454
	case RES_LIMIT:
3455 3456 3457 3458
		if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
			ret = -EINVAL;
			break;
		}
3459 3460
		/* This function does all necessary parse...reuse it */
		ret = res_counter_memparse_write_strategy(buffer, &val);
3461 3462 3463
		if (ret)
			break;
		if (type == _MEM)
3464
			ret = mem_cgroup_resize_limit(memcg, val);
3465 3466
		else
			ret = mem_cgroup_resize_memsw_limit(memcg, val);
3467
		break;
3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481
	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;
3482 3483 3484 3485 3486
	default:
		ret = -EINVAL; /* should be BUG() ? */
		break;
	}
	return ret;
B
Balbir Singh 已提交
3487 3488
}

3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516
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;
}

3517
static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
3518 3519
{
	struct mem_cgroup *mem;
3520
	int type, name;
3521 3522

	mem = mem_cgroup_from_cont(cont);
3523 3524 3525
	type = MEMFILE_TYPE(event);
	name = MEMFILE_ATTR(event);
	switch (name) {
3526
	case RES_MAX_USAGE:
3527 3528 3529 3530
		if (type == _MEM)
			res_counter_reset_max(&mem->res);
		else
			res_counter_reset_max(&mem->memsw);
3531 3532
		break;
	case RES_FAILCNT:
3533 3534 3535 3536
		if (type == _MEM)
			res_counter_reset_failcnt(&mem->res);
		else
			res_counter_reset_failcnt(&mem->memsw);
3537 3538
		break;
	}
3539

3540
	return 0;
3541 3542
}

3543 3544 3545 3546 3547 3548
static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
					struct cftype *cft)
{
	return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
}

3549
#ifdef CONFIG_MMU
3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567
static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
					struct cftype *cft, u64 val)
{
	struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);

	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();
	mem->move_charge_at_immigrate = val;
	cgroup_unlock();

	return 0;
}
3568 3569 3570 3571 3572 3573 3574
#else
static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
					struct cftype *cft, u64 val)
{
	return -ENOSYS;
}
#endif
3575

K
KAMEZAWA Hiroyuki 已提交
3576 3577 3578 3579 3580

/* For read statistics */
enum {
	MCS_CACHE,
	MCS_RSS,
3581
	MCS_FILE_MAPPED,
K
KAMEZAWA Hiroyuki 已提交
3582 3583
	MCS_PGPGIN,
	MCS_PGPGOUT,
3584
	MCS_SWAP,
K
KAMEZAWA Hiroyuki 已提交
3585 3586 3587 3588 3589 3590 3591 3592 3593 3594
	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];
3595 3596
};

K
KAMEZAWA Hiroyuki 已提交
3597 3598 3599 3600 3601 3602
struct {
	char *local_name;
	char *total_name;
} memcg_stat_strings[NR_MCS_STAT] = {
	{"cache", "total_cache"},
	{"rss", "total_rss"},
3603
	{"mapped_file", "total_mapped_file"},
K
KAMEZAWA Hiroyuki 已提交
3604 3605
	{"pgpgin", "total_pgpgin"},
	{"pgpgout", "total_pgpgout"},
3606
	{"swap", "total_swap"},
K
KAMEZAWA Hiroyuki 已提交
3607 3608 3609 3610 3611 3612 3613 3614
	{"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
3615 3616
static void
mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
K
KAMEZAWA Hiroyuki 已提交
3617 3618 3619 3620
{
	s64 val;

	/* per cpu stat */
3621
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
K
KAMEZAWA Hiroyuki 已提交
3622
	s->stat[MCS_CACHE] += val * PAGE_SIZE;
3623
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
K
KAMEZAWA Hiroyuki 已提交
3624
	s->stat[MCS_RSS] += val * PAGE_SIZE;
3625
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED);
3626
	s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
3627
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGIN_COUNT);
K
KAMEZAWA Hiroyuki 已提交
3628
	s->stat[MCS_PGPGIN] += val;
3629
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGOUT_COUNT);
K
KAMEZAWA Hiroyuki 已提交
3630
	s->stat[MCS_PGPGOUT] += val;
3631
	if (do_swap_account) {
3632
		val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
3633 3634
		s->stat[MCS_SWAP] += val * PAGE_SIZE;
	}
K
KAMEZAWA Hiroyuki 已提交
3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651

	/* per zone stat */
	val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
	s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
	val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON);
	s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE;
	val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE);
	s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE;
	val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE);
	s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE;
	val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE);
	s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE;
}

static void
mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
{
K
KAMEZAWA Hiroyuki 已提交
3652 3653 3654 3655
	struct mem_cgroup *iter;

	for_each_mem_cgroup_tree(iter, mem)
		mem_cgroup_get_local_stat(iter, s);
K
KAMEZAWA Hiroyuki 已提交
3656 3657
}

3658 3659
static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
				 struct cgroup_map_cb *cb)
3660 3661
{
	struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
K
KAMEZAWA Hiroyuki 已提交
3662
	struct mcs_total_stat mystat;
3663 3664
	int i;

K
KAMEZAWA Hiroyuki 已提交
3665 3666
	memset(&mystat, 0, sizeof(mystat));
	mem_cgroup_get_local_stat(mem_cont, &mystat);
3667

3668 3669 3670
	for (i = 0; i < NR_MCS_STAT; i++) {
		if (i == MCS_SWAP && !do_swap_account)
			continue;
K
KAMEZAWA Hiroyuki 已提交
3671
		cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
3672
	}
L
Lee Schermerhorn 已提交
3673

K
KAMEZAWA Hiroyuki 已提交
3674
	/* Hierarchical information */
3675 3676 3677 3678 3679 3680 3681
	{
		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
3682

K
KAMEZAWA Hiroyuki 已提交
3683 3684
	memset(&mystat, 0, sizeof(mystat));
	mem_cgroup_get_total_stat(mem_cont, &mystat);
3685 3686 3687
	for (i = 0; i < NR_MCS_STAT; i++) {
		if (i == MCS_SWAP && !do_swap_account)
			continue;
K
KAMEZAWA Hiroyuki 已提交
3688
		cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
3689
	}
K
KAMEZAWA Hiroyuki 已提交
3690

K
KOSAKI Motohiro 已提交
3691
#ifdef CONFIG_DEBUG_VM
3692
	cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
K
KOSAKI Motohiro 已提交
3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719

	{
		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

3720 3721 3722
	return 0;
}

K
KOSAKI Motohiro 已提交
3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733 3734
static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);

	return get_swappiness(memcg);
}

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;
3735

K
KOSAKI Motohiro 已提交
3736 3737 3738 3739 3740 3741 3742
	if (val > 100)
		return -EINVAL;

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

	parent = mem_cgroup_from_cont(cgrp->parent);
3743 3744 3745

	cgroup_lock();

K
KOSAKI Motohiro 已提交
3746 3747
	/* If under hierarchy, only empty-root can set this value */
	if ((parent->use_hierarchy) ||
3748 3749
	    (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
		cgroup_unlock();
K
KOSAKI Motohiro 已提交
3750
		return -EINVAL;
3751
	}
K
KOSAKI Motohiro 已提交
3752 3753 3754 3755 3756

	spin_lock(&memcg->reclaim_param_lock);
	memcg->swappiness = val;
	spin_unlock(&memcg->reclaim_param_lock);

3757 3758
	cgroup_unlock();

K
KOSAKI Motohiro 已提交
3759 3760 3761
	return 0;
}

3762 3763 3764 3765 3766 3767 3768 3769
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)
3770
		t = rcu_dereference(memcg->thresholds.primary);
3771
	else
3772
		t = rcu_dereference(memcg->memsw_thresholds.primary);
3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783

	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().
	 */
3784
	i = t->current_threshold;
3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803 3804 3805 3806 3807

	/*
	 * 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 */
3808
	t->current_threshold = i - 1;
3809 3810 3811 3812 3813 3814
unlock:
	rcu_read_unlock();
}

static void mem_cgroup_threshold(struct mem_cgroup *memcg)
{
3815 3816 3817 3818 3819 3820 3821
	while (memcg) {
		__mem_cgroup_threshold(memcg, false);
		if (do_swap_account)
			__mem_cgroup_threshold(memcg, true);

		memcg = parent_mem_cgroup(memcg);
	}
3822 3823 3824 3825 3826 3827 3828 3829 3830 3831
}

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;
}

K
KAMEZAWA Hiroyuki 已提交
3832
static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem)
K
KAMEZAWA Hiroyuki 已提交
3833 3834 3835 3836 3837 3838 3839 3840 3841 3842
{
	struct mem_cgroup_eventfd_list *ev;

	list_for_each_entry(ev, &mem->oom_notify, list)
		eventfd_signal(ev->eventfd, 1);
	return 0;
}

static void mem_cgroup_oom_notify(struct mem_cgroup *mem)
{
K
KAMEZAWA Hiroyuki 已提交
3843 3844 3845 3846
	struct mem_cgroup *iter;

	for_each_mem_cgroup_tree(iter, mem)
		mem_cgroup_oom_notify_cb(iter);
K
KAMEZAWA Hiroyuki 已提交
3847 3848 3849 3850
}

static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
	struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
3851 3852
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3853 3854
	struct mem_cgroup_thresholds *thresholds;
	struct mem_cgroup_threshold_ary *new;
3855 3856
	int type = MEMFILE_TYPE(cft->private);
	u64 threshold, usage;
3857
	int i, size, ret;
3858 3859 3860 3861 3862 3863

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

	mutex_lock(&memcg->thresholds_lock);
3864

3865
	if (type == _MEM)
3866
		thresholds = &memcg->thresholds;
3867
	else if (type == _MEMSWAP)
3868
		thresholds = &memcg->memsw_thresholds;
3869 3870 3871 3872 3873 3874
	else
		BUG();

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

	/* Check if a threshold crossed before adding a new one */
3875
	if (thresholds->primary)
3876 3877
		__mem_cgroup_threshold(memcg, type == _MEMSWAP);

3878
	size = thresholds->primary ? thresholds->primary->size + 1 : 1;
3879 3880

	/* Allocate memory for new array of thresholds */
3881
	new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
3882
			GFP_KERNEL);
3883
	if (!new) {
3884 3885 3886
		ret = -ENOMEM;
		goto unlock;
	}
3887
	new->size = size;
3888 3889

	/* Copy thresholds (if any) to new array */
3890 3891
	if (thresholds->primary) {
		memcpy(new->entries, thresholds->primary->entries, (size - 1) *
3892
				sizeof(struct mem_cgroup_threshold));
3893 3894
	}

3895
	/* Add new threshold */
3896 3897
	new->entries[size - 1].eventfd = eventfd;
	new->entries[size - 1].threshold = threshold;
3898 3899

	/* Sort thresholds. Registering of new threshold isn't time-critical */
3900
	sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
3901 3902 3903
			compare_thresholds, NULL);

	/* Find current threshold */
3904
	new->current_threshold = -1;
3905
	for (i = 0; i < size; i++) {
3906
		if (new->entries[i].threshold < usage) {
3907
			/*
3908 3909
			 * new->current_threshold will not be used until
			 * rcu_assign_pointer(), so it's safe to increment
3910 3911
			 * it here.
			 */
3912
			++new->current_threshold;
3913 3914 3915
		}
	}

3916 3917 3918 3919 3920
	/* Free old spare buffer and save old primary buffer as spare */
	kfree(thresholds->spare);
	thresholds->spare = thresholds->primary;

	rcu_assign_pointer(thresholds->primary, new);
3921

3922
	/* To be sure that nobody uses thresholds */
3923 3924 3925 3926 3927 3928 3929 3930
	synchronize_rcu();

unlock:
	mutex_unlock(&memcg->thresholds_lock);

	return ret;
}

3931
static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
K
KAMEZAWA Hiroyuki 已提交
3932
	struct cftype *cft, struct eventfd_ctx *eventfd)
3933 3934
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3935 3936
	struct mem_cgroup_thresholds *thresholds;
	struct mem_cgroup_threshold_ary *new;
3937 3938
	int type = MEMFILE_TYPE(cft->private);
	u64 usage;
3939
	int i, j, size;
3940 3941 3942

	mutex_lock(&memcg->thresholds_lock);
	if (type == _MEM)
3943
		thresholds = &memcg->thresholds;
3944
	else if (type == _MEMSWAP)
3945
		thresholds = &memcg->memsw_thresholds;
3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 3960
	else
		BUG();

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

	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 */
3961 3962 3963
	size = 0;
	for (i = 0; i < thresholds->primary->size; i++) {
		if (thresholds->primary->entries[i].eventfd != eventfd)
3964 3965 3966
			size++;
	}

3967
	new = thresholds->spare;
3968

3969 3970
	/* Set thresholds array to NULL if we don't have thresholds */
	if (!size) {
3971 3972
		kfree(new);
		new = NULL;
3973
		goto swap_buffers;
3974 3975
	}

3976
	new->size = size;
3977 3978

	/* Copy thresholds and find current threshold */
3979 3980 3981
	new->current_threshold = -1;
	for (i = 0, j = 0; i < thresholds->primary->size; i++) {
		if (thresholds->primary->entries[i].eventfd == eventfd)
3982 3983
			continue;

3984 3985
		new->entries[j] = thresholds->primary->entries[i];
		if (new->entries[j].threshold < usage) {
3986
			/*
3987
			 * new->current_threshold will not be used
3988 3989 3990
			 * until rcu_assign_pointer(), so it's safe to increment
			 * it here.
			 */
3991
			++new->current_threshold;
3992 3993 3994 3995
		}
		j++;
	}

3996
swap_buffers:
3997 3998 3999
	/* Swap primary and spare array */
	thresholds->spare = thresholds->primary;
	rcu_assign_pointer(thresholds->primary, new);
4000

4001
	/* To be sure that nobody uses thresholds */
4002 4003 4004 4005
	synchronize_rcu();

	mutex_unlock(&memcg->thresholds_lock);
}
4006

K
KAMEZAWA Hiroyuki 已提交
4007 4008 4009 4010 4011 4012 4013 4014 4015 4016 4017 4018 4019 4020 4021 4022 4023 4024 4025 4026 4027 4028 4029 4030 4031
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;

	mutex_lock(&memcg_oom_mutex);

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

	/* already in OOM ? */
	if (atomic_read(&memcg->oom_lock))
		eventfd_signal(eventfd, 1);
	mutex_unlock(&memcg_oom_mutex);

	return 0;
}

4032
static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
K
KAMEZAWA Hiroyuki 已提交
4033 4034 4035 4036 4037 4038 4039 4040 4041 4042 4043 4044 4045 4046 4047 4048 4049 4050 4051 4052
	struct cftype *cft, struct eventfd_ctx *eventfd)
{
	struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
	struct mem_cgroup_eventfd_list *ev, *tmp;
	int type = MEMFILE_TYPE(cft->private);

	BUG_ON(type != _OOM_TYPE);

	mutex_lock(&memcg_oom_mutex);

	list_for_each_entry_safe(ev, tmp, &mem->oom_notify, list) {
		if (ev->eventfd == eventfd) {
			list_del(&ev->list);
			kfree(ev);
		}
	}

	mutex_unlock(&memcg_oom_mutex);
}

4053 4054 4055 4056 4057 4058 4059 4060 4061 4062 4063 4064 4065 4066 4067 4068 4069 4070 4071 4072 4073 4074 4075 4076 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086
static int mem_cgroup_oom_control_read(struct cgroup *cgrp,
	struct cftype *cft,  struct cgroup_map_cb *cb)
{
	struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);

	cb->fill(cb, "oom_kill_disable", mem->oom_kill_disable);

	if (atomic_read(&mem->oom_lock))
		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)
{
	struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
	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) ||
	    (mem->use_hierarchy && !list_empty(&cgrp->children))) {
		cgroup_unlock();
		return -EINVAL;
	}
	mem->oom_kill_disable = val;
4087 4088
	if (!val)
		memcg_oom_recover(mem);
4089 4090 4091 4092
	cgroup_unlock();
	return 0;
}

B
Balbir Singh 已提交
4093 4094
static struct cftype mem_cgroup_files[] = {
	{
4095
		.name = "usage_in_bytes",
4096
		.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4097
		.read_u64 = mem_cgroup_read,
K
KAMEZAWA Hiroyuki 已提交
4098 4099
		.register_event = mem_cgroup_usage_register_event,
		.unregister_event = mem_cgroup_usage_unregister_event,
B
Balbir Singh 已提交
4100
	},
4101 4102
	{
		.name = "max_usage_in_bytes",
4103
		.private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4104
		.trigger = mem_cgroup_reset,
4105 4106
		.read_u64 = mem_cgroup_read,
	},
B
Balbir Singh 已提交
4107
	{
4108
		.name = "limit_in_bytes",
4109
		.private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4110
		.write_string = mem_cgroup_write,
4111
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
4112
	},
4113 4114 4115 4116 4117 4118
	{
		.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
4119 4120
	{
		.name = "failcnt",
4121
		.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4122
		.trigger = mem_cgroup_reset,
4123
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
4124
	},
4125 4126
	{
		.name = "stat",
4127
		.read_map = mem_control_stat_show,
4128
	},
4129 4130 4131 4132
	{
		.name = "force_empty",
		.trigger = mem_cgroup_force_empty_write,
	},
4133 4134 4135 4136 4137
	{
		.name = "use_hierarchy",
		.write_u64 = mem_cgroup_hierarchy_write,
		.read_u64 = mem_cgroup_hierarchy_read,
	},
K
KOSAKI Motohiro 已提交
4138 4139 4140 4141 4142
	{
		.name = "swappiness",
		.read_u64 = mem_cgroup_swappiness_read,
		.write_u64 = mem_cgroup_swappiness_write,
	},
4143 4144 4145 4146 4147
	{
		.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
4148 4149
	{
		.name = "oom_control",
4150 4151
		.read_map = mem_cgroup_oom_control_read,
		.write_u64 = mem_cgroup_oom_control_write,
K
KAMEZAWA Hiroyuki 已提交
4152 4153 4154 4155
		.register_event = mem_cgroup_oom_register_event,
		.unregister_event = mem_cgroup_oom_unregister_event,
		.private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
	},
B
Balbir Singh 已提交
4156 4157
};

4158 4159 4160 4161 4162 4163
#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
4164 4165
		.register_event = mem_cgroup_usage_register_event,
		.unregister_event = mem_cgroup_usage_unregister_event,
4166 4167 4168 4169 4170 4171 4172 4173 4174 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
	},
	{
		.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

4201 4202 4203
static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
	struct mem_cgroup_per_node *pn;
4204
	struct mem_cgroup_per_zone *mz;
4205
	enum lru_list l;
4206
	int zone, tmp = node;
4207 4208 4209 4210 4211 4212 4213 4214
	/*
	 * 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.
	 */
4215 4216 4217
	if (!node_state(node, N_NORMAL_MEMORY))
		tmp = -1;
	pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4218 4219
	if (!pn)
		return 1;
4220

4221 4222
	mem->info.nodeinfo[node] = pn;
	memset(pn, 0, sizeof(*pn));
4223 4224 4225

	for (zone = 0; zone < MAX_NR_ZONES; zone++) {
		mz = &pn->zoneinfo[zone];
4226 4227
		for_each_lru(l)
			INIT_LIST_HEAD(&mz->lists[l]);
4228
		mz->usage_in_excess = 0;
4229 4230
		mz->on_tree = false;
		mz->mem = mem;
4231
	}
4232 4233 4234
	return 0;
}

4235 4236 4237 4238 4239
static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
	kfree(mem->info.nodeinfo[node]);
}

4240 4241 4242
static struct mem_cgroup *mem_cgroup_alloc(void)
{
	struct mem_cgroup *mem;
4243
	int size = sizeof(struct mem_cgroup);
4244

4245
	/* Can be very big if MAX_NUMNODES is very big */
4246 4247
	if (size < PAGE_SIZE)
		mem = kmalloc(size, GFP_KERNEL);
4248
	else
4249
		mem = vmalloc(size);
4250

4251 4252 4253 4254
	if (!mem)
		return NULL;

	memset(mem, 0, size);
4255
	mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4256 4257
	if (!mem->stat)
		goto out_free;
4258
	spin_lock_init(&mem->pcp_counter_lock);
4259
	return mem;
4260 4261 4262 4263 4264 4265 4266

out_free:
	if (size < PAGE_SIZE)
		kfree(mem);
	else
		vfree(mem);
	return NULL;
4267 4268
}

4269 4270 4271 4272 4273 4274 4275 4276 4277 4278 4279
/*
 * 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.
 */

4280
static void __mem_cgroup_free(struct mem_cgroup *mem)
4281
{
K
KAMEZAWA Hiroyuki 已提交
4282 4283
	int node;

4284
	mem_cgroup_remove_from_trees(mem);
K
KAMEZAWA Hiroyuki 已提交
4285 4286
	free_css_id(&mem_cgroup_subsys, &mem->css);

K
KAMEZAWA Hiroyuki 已提交
4287 4288 4289
	for_each_node_state(node, N_POSSIBLE)
		free_mem_cgroup_per_zone_info(mem, node);

4290 4291
	free_percpu(mem->stat);
	if (sizeof(struct mem_cgroup) < PAGE_SIZE)
4292 4293 4294 4295 4296
		kfree(mem);
	else
		vfree(mem);
}

4297 4298 4299 4300 4301
static void mem_cgroup_get(struct mem_cgroup *mem)
{
	atomic_inc(&mem->refcnt);
}

4302
static void __mem_cgroup_put(struct mem_cgroup *mem, int count)
4303
{
4304
	if (atomic_sub_and_test(count, &mem->refcnt)) {
4305
		struct mem_cgroup *parent = parent_mem_cgroup(mem);
4306
		__mem_cgroup_free(mem);
4307 4308 4309
		if (parent)
			mem_cgroup_put(parent);
	}
4310 4311
}

4312 4313 4314 4315 4316
static void mem_cgroup_put(struct mem_cgroup *mem)
{
	__mem_cgroup_put(mem, 1);
}

4317 4318 4319 4320 4321 4322 4323 4324 4325
/*
 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
 */
static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem)
{
	if (!mem->res.parent)
		return NULL;
	return mem_cgroup_from_res_counter(mem->res.parent, res);
}
4326

4327 4328 4329
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
static void __init enable_swap_cgroup(void)
{
4330
	if (!mem_cgroup_disabled() && really_do_swap_account)
4331 4332 4333 4334 4335 4336 4337 4338
		do_swap_account = 1;
}
#else
static void __init enable_swap_cgroup(void)
{
}
#endif

4339 4340 4341 4342 4343 4344 4345 4346 4347 4348 4349 4350 4351 4352 4353 4354 4355 4356 4357 4358 4359 4360 4361 4362 4363
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;

	for_each_node_state(node, N_POSSIBLE) {
		tmp = node;
		if (!node_state(node, N_NORMAL_MEMORY))
			tmp = -1;
		rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
		if (!rtpn)
			return 1;

		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;
}

L
Li Zefan 已提交
4364
static struct cgroup_subsys_state * __ref
B
Balbir Singh 已提交
4365 4366
mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
{
4367
	struct mem_cgroup *mem, *parent;
K
KAMEZAWA Hiroyuki 已提交
4368
	long error = -ENOMEM;
4369
	int node;
B
Balbir Singh 已提交
4370

4371 4372
	mem = mem_cgroup_alloc();
	if (!mem)
K
KAMEZAWA Hiroyuki 已提交
4373
		return ERR_PTR(error);
4374

4375 4376 4377
	for_each_node_state(node, N_POSSIBLE)
		if (alloc_mem_cgroup_per_zone_info(mem, node))
			goto free_out;
4378

4379
	/* root ? */
4380
	if (cont->parent == NULL) {
4381
		int cpu;
4382
		enable_swap_cgroup();
4383
		parent = NULL;
4384
		root_mem_cgroup = mem;
4385 4386
		if (mem_cgroup_soft_limit_tree_init())
			goto free_out;
4387 4388 4389 4390 4391
		for_each_possible_cpu(cpu) {
			struct memcg_stock_pcp *stock =
						&per_cpu(memcg_stock, cpu);
			INIT_WORK(&stock->work, drain_local_stock);
		}
4392
		hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
4393
	} else {
4394
		parent = mem_cgroup_from_cont(cont->parent);
4395
		mem->use_hierarchy = parent->use_hierarchy;
4396
		mem->oom_kill_disable = parent->oom_kill_disable;
4397
	}
4398

4399 4400 4401
	if (parent && parent->use_hierarchy) {
		res_counter_init(&mem->res, &parent->res);
		res_counter_init(&mem->memsw, &parent->memsw);
4402 4403 4404 4405 4406 4407 4408
		/*
		 * 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);
4409 4410 4411 4412
	} else {
		res_counter_init(&mem->res, NULL);
		res_counter_init(&mem->memsw, NULL);
	}
K
KAMEZAWA Hiroyuki 已提交
4413
	mem->last_scanned_child = 0;
K
KOSAKI Motohiro 已提交
4414
	spin_lock_init(&mem->reclaim_param_lock);
K
KAMEZAWA Hiroyuki 已提交
4415
	INIT_LIST_HEAD(&mem->oom_notify);
4416

K
KOSAKI Motohiro 已提交
4417 4418
	if (parent)
		mem->swappiness = get_swappiness(parent);
4419
	atomic_set(&mem->refcnt, 1);
4420
	mem->move_charge_at_immigrate = 0;
4421
	mutex_init(&mem->thresholds_lock);
B
Balbir Singh 已提交
4422
	return &mem->css;
4423
free_out:
4424
	__mem_cgroup_free(mem);
4425
	root_mem_cgroup = NULL;
K
KAMEZAWA Hiroyuki 已提交
4426
	return ERR_PTR(error);
B
Balbir Singh 已提交
4427 4428
}

4429
static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
4430 4431 4432
					struct cgroup *cont)
{
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4433 4434

	return mem_cgroup_force_empty(mem, false);
4435 4436
}

B
Balbir Singh 已提交
4437 4438 4439
static void mem_cgroup_destroy(struct cgroup_subsys *ss,
				struct cgroup *cont)
{
4440 4441 4442
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);

	mem_cgroup_put(mem);
B
Balbir Singh 已提交
4443 4444 4445 4446 4447
}

static int mem_cgroup_populate(struct cgroup_subsys *ss,
				struct cgroup *cont)
{
4448 4449 4450 4451 4452 4453 4454 4455
	int ret;

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

	if (!ret)
		ret = register_memsw_files(cont, ss);
	return ret;
B
Balbir Singh 已提交
4456 4457
}

4458
#ifdef CONFIG_MMU
4459
/* Handlers for move charge at task migration. */
4460 4461
#define PRECHARGE_COUNT_AT_ONCE	256
static int mem_cgroup_do_precharge(unsigned long count)
4462
{
4463 4464
	int ret = 0;
	int batch_count = PRECHARGE_COUNT_AT_ONCE;
4465 4466
	struct mem_cgroup *mem = mc.to;

4467 4468 4469 4470 4471 4472 4473 4474 4475 4476 4477 4478 4479 4480 4481 4482 4483 4484 4485 4486 4487 4488 4489 4490 4491 4492 4493 4494 4495 4496 4497 4498 4499 4500 4501
	if (mem_cgroup_is_root(mem)) {
		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;
		/*
		 * "mem" cannot be under rmdir() because we've already checked
		 * 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().
		 */
		if (res_counter_charge(&mem->res, PAGE_SIZE * count, &dummy))
			goto one_by_one;
		if (do_swap_account && res_counter_charge(&mem->memsw,
						PAGE_SIZE * count, &dummy)) {
			res_counter_uncharge(&mem->res, PAGE_SIZE * count);
			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();
		}
A
Andrea Arcangeli 已提交
4502 4503
		ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false,
					      PAGE_SIZE);
4504 4505 4506 4507 4508
		if (ret || !mem)
			/* mem_cgroup_clear_mc() will do uncharge later */
			return -ENOMEM;
		mc.precharge++;
	}
4509 4510 4511 4512 4513 4514 4515 4516
	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
4517
 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4518 4519 4520 4521 4522 4523
 *
 * 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).
4524 4525 4526
 *   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.
4527 4528 4529 4530 4531
 *
 * Called with pte lock held.
 */
union mc_target {
	struct page	*page;
4532
	swp_entry_t	ent;
4533 4534 4535 4536 4537
};

enum mc_target_type {
	MC_TARGET_NONE,	/* not used */
	MC_TARGET_PAGE,
4538
	MC_TARGET_SWAP,
4539 4540
};

D
Daisuke Nishimura 已提交
4541 4542
static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
						unsigned long addr, pte_t ptent)
4543
{
D
Daisuke Nishimura 已提交
4544
	struct page *page = vm_normal_page(vma, addr, ptent);
4545

D
Daisuke Nishimura 已提交
4546 4547 4548 4549 4550 4551
	if (!page || !page_mapped(page))
		return NULL;
	if (PageAnon(page)) {
		/* we don't move shared anon */
		if (!move_anon() || page_mapcount(page) > 2)
			return NULL;
4552 4553
	} else if (!move_file())
		/* we ignore mapcount for file pages */
D
Daisuke Nishimura 已提交
4554 4555 4556 4557 4558 4559 4560 4561 4562 4563 4564 4565 4566 4567 4568 4569 4570 4571
		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 */
4572 4573
		if (page)
			put_page(page);
D
Daisuke Nishimura 已提交
4574
		return NULL;
4575
	}
D
Daisuke Nishimura 已提交
4576 4577 4578 4579 4580 4581
	if (do_swap_account)
		entry->val = ent.val;

	return page;
}

4582 4583 4584 4585 4586 4587 4588 4589 4590 4591 4592 4593 4594 4595 4596 4597 4598 4599 4600 4601 4602 4603 4604 4605 4606 4607 4608 4609 4610 4611 4612 4613 4614
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). */
	if (!mapping_cap_swap_backed(mapping)) { /* normal file */
		page = find_get_page(mapping, pgoff);
	} else { /* shmem/tmpfs file. we should take account of swap too. */
		swp_entry_t ent;
		mem_cgroup_get_shmem_target(inode, pgoff, &page, &ent);
		if (do_swap_account)
			entry->val = ent.val;
	}

	return page;
}

D
Daisuke Nishimura 已提交
4615 4616 4617 4618 4619 4620 4621 4622 4623 4624 4625 4626
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);
4627 4628
	else if (pte_none(ptent) || pte_file(ptent))
		page = mc_handle_file_pte(vma, addr, ptent, &ent);
D
Daisuke Nishimura 已提交
4629 4630 4631

	if (!page && !ent.val)
		return 0;
4632 4633 4634 4635 4636 4637 4638 4639 4640 4641 4642 4643 4644 4645 4646
	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
4647 4648
	/* There is a swap entry and a page doesn't exist or isn't charged */
	if (ent.val && !ret &&
4649 4650 4651 4652
			css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
		ret = MC_TARGET_SWAP;
		if (target)
			target->ent = ent;
4653 4654 4655 4656 4657 4658 4659 4660 4661 4662 4663 4664
	}
	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;

A
Andrea Arcangeli 已提交
4665
	VM_BUG_ON(pmd_trans_huge(*pmd));
4666 4667 4668 4669 4670 4671 4672
	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();

4673 4674 4675
	return 0;
}

4676 4677 4678 4679 4680
static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
{
	unsigned long precharge;
	struct vm_area_struct *vma;

4681
	/* We've already held the mmap_sem */
4682 4683 4684 4685 4686 4687 4688 4689 4690 4691 4692 4693 4694 4695 4696 4697 4698 4699 4700 4701
	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);
	}

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

	return precharge;
}

static int mem_cgroup_precharge_mc(struct mm_struct *mm)
{
4702
	return mem_cgroup_do_precharge(mem_cgroup_count_precharge(mm));
4703 4704 4705 4706
}

static void mem_cgroup_clear_mc(void)
{
4707 4708 4709
	struct mem_cgroup *from = mc.from;
	struct mem_cgroup *to = mc.to;

4710
	/* we must uncharge all the leftover precharges from mc.to */
4711 4712 4713 4714 4715 4716 4717 4718 4719 4720 4721
	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;
4722
	}
4723 4724 4725 4726 4727 4728 4729 4730 4731 4732 4733 4734 4735 4736 4737 4738 4739 4740 4741 4742
	/* 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;
	}
4743 4744 4745 4746
	if (mc.mm) {
		up_read(&mc.mm->mmap_sem);
		mmput(mc.mm);
	}
4747
	spin_lock(&mc.lock);
4748 4749
	mc.from = NULL;
	mc.to = NULL;
4750
	spin_unlock(&mc.lock);
4751 4752
	mc.moving_task = NULL;
	mc.mm = NULL;
4753
	mem_cgroup_end_move(from);
4754 4755
	memcg_oom_recover(from);
	memcg_oom_recover(to);
4756
	wake_up_all(&mc.waitq);
4757 4758
}

4759 4760 4761 4762 4763 4764 4765 4766 4767 4768 4769 4770 4771 4772 4773 4774 4775 4776
static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
				struct cgroup *cgroup,
				struct task_struct *p,
				bool threadgroup)
{
	int ret = 0;
	struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup);

	if (mem->move_charge_at_immigrate) {
		struct mm_struct *mm;
		struct mem_cgroup *from = mem_cgroup_from_task(p);

		VM_BUG_ON(from == mem);

		mm = get_task_mm(p);
		if (!mm)
			return 0;
		/* We move charges only when we move a owner of the mm */
4777
		if (mm->owner == p) {
4778 4779 4780 4781 4782 4783 4784
			/*
			 * We do all the move charge works under one mmap_sem to
			 * avoid deadlock with down_write(&mmap_sem)
			 * -> try_charge() -> if (mc.moving_task) -> sleep.
			 */
			down_read(&mm->mmap_sem);

4785 4786 4787
			VM_BUG_ON(mc.from);
			VM_BUG_ON(mc.to);
			VM_BUG_ON(mc.precharge);
4788
			VM_BUG_ON(mc.moved_charge);
4789
			VM_BUG_ON(mc.moved_swap);
4790
			VM_BUG_ON(mc.moving_task);
4791 4792
			VM_BUG_ON(mc.mm);

4793
			mem_cgroup_start_move(from);
4794
			spin_lock(&mc.lock);
4795 4796 4797
			mc.from = from;
			mc.to = mem;
			mc.precharge = 0;
4798
			mc.moved_charge = 0;
4799
			mc.moved_swap = 0;
4800
			spin_unlock(&mc.lock);
4801 4802
			mc.moving_task = current;
			mc.mm = mm;
4803 4804 4805 4806

			ret = mem_cgroup_precharge_mc(mm);
			if (ret)
				mem_cgroup_clear_mc();
4807 4808 4809
			/* We call up_read() and mmput() in clear_mc(). */
		} else
			mmput(mm);
4810 4811 4812 4813 4814 4815 4816 4817 4818
	}
	return ret;
}

static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
				struct cgroup *cgroup,
				struct task_struct *p,
				bool threadgroup)
{
4819
	mem_cgroup_clear_mc();
4820 4821
}

4822 4823 4824
static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
				unsigned long addr, unsigned long end,
				struct mm_walk *walk)
4825
{
4826 4827 4828 4829 4830 4831
	int ret = 0;
	struct vm_area_struct *vma = walk->private;
	pte_t *pte;
	spinlock_t *ptl;

retry:
A
Andrea Arcangeli 已提交
4832
	VM_BUG_ON(pmd_trans_huge(*pmd));
4833 4834 4835 4836 4837 4838 4839
	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;
4840
		swp_entry_t ent;
4841 4842 4843 4844 4845 4846 4847 4848 4849 4850 4851

		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);
4852 4853
			if (!mem_cgroup_move_account(pc,
						mc.from, mc.to, false)) {
4854
				mc.precharge--;
4855 4856
				/* we uncharge from mc.from later. */
				mc.moved_charge++;
4857 4858 4859 4860 4861
			}
			putback_lru_page(page);
put:			/* is_target_pte_for_mc() gets the page */
			put_page(page);
			break;
4862 4863
		case MC_TARGET_SWAP:
			ent = target.ent;
4864 4865
			if (!mem_cgroup_move_swap_account(ent,
						mc.from, mc.to, false)) {
4866
				mc.precharge--;
4867 4868 4869
				/* we fixup refcnts and charges later. */
				mc.moved_swap++;
			}
4870
			break;
4871 4872 4873 4874 4875 4876 4877 4878 4879 4880 4881 4882 4883 4884
		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.
		 */
4885
		ret = mem_cgroup_do_precharge(1);
4886 4887 4888 4889 4890 4891 4892 4893 4894 4895 4896 4897
		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();
4898
	/* We've already held the mmap_sem */
4899 4900 4901 4902 4903 4904 4905 4906 4907 4908 4909 4910 4911 4912 4913 4914 4915 4916
	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;
	}
4917 4918
}

B
Balbir Singh 已提交
4919 4920 4921
static void mem_cgroup_move_task(struct cgroup_subsys *ss,
				struct cgroup *cont,
				struct cgroup *old_cont,
4922 4923
				struct task_struct *p,
				bool threadgroup)
B
Balbir Singh 已提交
4924
{
4925
	if (!mc.mm)
4926 4927 4928
		/* no need to move charge */
		return;

4929
	mem_cgroup_move_charge(mc.mm);
4930
	mem_cgroup_clear_mc();
B
Balbir Singh 已提交
4931
}
4932 4933 4934 4935 4936 4937 4938 4939 4940 4941 4942 4943 4944 4945 4946 4947 4948 4949 4950 4951 4952 4953
#else	/* !CONFIG_MMU */
static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
				struct cgroup *cgroup,
				struct task_struct *p,
				bool threadgroup)
{
	return 0;
}
static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
				struct cgroup *cgroup,
				struct task_struct *p,
				bool threadgroup)
{
}
static void mem_cgroup_move_task(struct cgroup_subsys *ss,
				struct cgroup *cont,
				struct cgroup *old_cont,
				struct task_struct *p,
				bool threadgroup)
{
}
#endif
B
Balbir Singh 已提交
4954

B
Balbir Singh 已提交
4955 4956 4957 4958
struct cgroup_subsys mem_cgroup_subsys = {
	.name = "memory",
	.subsys_id = mem_cgroup_subsys_id,
	.create = mem_cgroup_create,
4959
	.pre_destroy = mem_cgroup_pre_destroy,
B
Balbir Singh 已提交
4960 4961
	.destroy = mem_cgroup_destroy,
	.populate = mem_cgroup_populate,
4962 4963
	.can_attach = mem_cgroup_can_attach,
	.cancel_attach = mem_cgroup_cancel_attach,
B
Balbir Singh 已提交
4964
	.attach = mem_cgroup_move_task,
4965
	.early_init = 0,
K
KAMEZAWA Hiroyuki 已提交
4966
	.use_id = 1,
B
Balbir Singh 已提交
4967
};
4968 4969

#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4970 4971 4972 4973 4974 4975 4976 4977 4978 4979
static int __init enable_swap_account(char *s)
{
	/* consider enabled if no parameter or 1 is given */
	if (!s || !strcmp(s, "1"))
		really_do_swap_account = 1;
	else if (!strcmp(s, "0"))
		really_do_swap_account = 0;
	return 1;
}
__setup("swapaccount", enable_swap_account);
4980 4981 4982

static int __init disable_swap_account(char *s)
{
4983
	enable_swap_account("0");
4984 4985 4986 4987
	return 1;
}
__setup("noswapaccount", disable_swap_account);
#endif