memcontrol.c 133.5 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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/*
 * Statistics for memory cgroup.
 */
enum mem_cgroup_stat_index {
	/*
	 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
	 */
	MEM_CGROUP_STAT_CACHE, 	   /* # of pages charged as cache */
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	MEM_CGROUP_STAT_RSS,	   /* # of pages charged as anon rss */
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	MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */
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	MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
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	MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */
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	MEM_CGROUP_ON_MOVE,	/* someone is moving account between groups */
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	MEM_CGROUP_STAT_NSTATS,
};

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

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/*
 * 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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	/*
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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 */
	wait_queue_head_t waitq;		/* a waitq for other context */
} mc = {
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	.lock = __SPIN_LOCK_UNLOCKED(mc.lock),
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	.waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
};
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static bool move_anon(void)
{
	return test_bit(MOVE_CHARGE_TYPE_ANON,
					&mc.to->move_charge_at_immigrate);
}

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

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

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

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/* for encoding cft->private value on file */
#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 *
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page_cgroup_zoneinfo(struct mem_cgroup *mem, struct page *page)
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{
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	int nid = page_to_nid(page);
	int zid = page_zonenum(page);
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	return mem_cgroup_zoneinfo(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 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 long mem_cgroup_read_stat(struct mem_cgroup *mem,
				 enum mem_cgroup_stat_index idx)
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{
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	long val = 0;
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	int cpu;

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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;
}

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static long mem_cgroup_local_usage(struct mem_cgroup *mem)
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{
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	long ret;
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	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 unsigned long mem_cgroup_read_events(struct mem_cgroup *mem,
					    enum mem_cgroup_events_index idx)
{
	unsigned long val = 0;
	int cpu;

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

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static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
605
					 bool file, int nr_pages)
606
{
607 608
	preempt_disable();

609 610
	if (file)
		__this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], nr_pages);
611
	else
612
		__this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], nr_pages);
613

614 615
	/* pagein of a big page is an event. So, ignore page size */
	if (nr_pages > 0)
616
		__this_cpu_inc(mem->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
617
	else {
618
		__this_cpu_inc(mem->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
619 620
		nr_pages = -nr_pages; /* for event */
	}
621

622
	__this_cpu_add(mem->stat->events[MEM_CGROUP_EVENTS_COUNT], nr_pages);
623

624
	preempt_enable();
625 626
}

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static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
628
					enum lru_list idx)
629 630 631 632 633 634 635 636 637 638 639
{
	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;
640 641
}

642 643 644 645 646 647 648 649 650 651 652
static bool __memcg_event_check(struct mem_cgroup *mem, int target)
{
	unsigned long val, next;

	val = this_cpu_read(mem->stat->events[MEM_CGROUP_EVENTS_COUNT]);
	next = this_cpu_read(mem->stat->targets[target]);
	/* from time_after() in jiffies.h */
	return ((long)next - (long)val < 0);
}

static void __mem_cgroup_target_update(struct mem_cgroup *mem, int target)
653
{
654
	unsigned long val, next;
655

656
	val = this_cpu_read(mem->stat->events[MEM_CGROUP_EVENTS_COUNT]);
657

658 659 660 661 662 663 664 665 666 667 668 669
	switch (target) {
	case MEM_CGROUP_TARGET_THRESH:
		next = val + THRESHOLDS_EVENTS_TARGET;
		break;
	case MEM_CGROUP_TARGET_SOFTLIMIT:
		next = val + SOFTLIMIT_EVENTS_TARGET;
		break;
	default:
		return;
	}

	this_cpu_write(mem->stat->targets[target], next);
670 671 672 673 674 675 676 677 678
}

/*
 * 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 */
679
	if (unlikely(__memcg_event_check(mem, MEM_CGROUP_TARGET_THRESH))) {
680
		mem_cgroup_threshold(mem);
681 682 683
		__mem_cgroup_target_update(mem, MEM_CGROUP_TARGET_THRESH);
		if (unlikely(__memcg_event_check(mem,
			MEM_CGROUP_TARGET_SOFTLIMIT))){
684
			mem_cgroup_update_tree(mem, page);
685 686 687
			__mem_cgroup_target_update(mem,
				MEM_CGROUP_TARGET_SOFTLIMIT);
		}
688 689 690
	}
}

691
static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
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692 693 694 695 696 697
{
	return container_of(cgroup_subsys_state(cont,
				mem_cgroup_subsys_id), struct mem_cgroup,
				css);
}

698
struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
699
{
700 701 702 703 704 705 706 707
	/*
	 * 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;

708 709 710 711
	return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
				struct mem_cgroup, css);
}

712 713 714
static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
{
	struct mem_cgroup *mem = NULL;
715 716 717

	if (!mm)
		return NULL;
718 719 720 721 722 723 724 725 726 727 728 729 730 731 732
	/*
	 * 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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733 734
/* The caller has to guarantee "mem" exists before calling this */
static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *mem)
K
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735
{
736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757
	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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769
	hierarchy_used = iter->use_hierarchy;
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770

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771
	css_put(&iter->css);
772 773
	/* If no ROOT, walk all, ignore hierarchy */
	if (!cond || (root && !hierarchy_used))
K
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774
		return NULL;
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775

776 777 778
	if (!root)
		root = root_mem_cgroup;

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779 780
	do {
		iter = NULL;
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781
		rcu_read_lock();
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782 783 784

		css = css_get_next(&mem_cgroup_subsys, nextid,
				&root->css, &found);
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785
		if (css && css_tryget(css))
K
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786
			iter = container_of(css, struct mem_cgroup, css);
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787
		rcu_read_unlock();
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788
		/* If css is NULL, no more cgroups will be found */
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789
		nextid = found + 1;
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790
	} while (css && !iter);
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791

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792
	return iter;
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793
}
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794 795 796 797 798 799 800 801 802 803 804 805 806
/*
 * 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)

807 808 809
#define for_each_mem_cgroup_all(iter) \
	for_each_mem_cgroup_tree_cond(iter, NULL, true)

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811 812 813 814 815
static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
{
	return (mem == root_mem_cgroup);
}

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816 817 818 819 820 821 822 823 824 825 826 827 828
/*
 * 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.
 */
829

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830 831 832 833
void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
{
	struct page_cgroup *pc;
	struct mem_cgroup_per_zone *mz;
834

835
	if (mem_cgroup_disabled())
K
KAMEZAWA Hiroyuki 已提交
836 837 838
		return;
	pc = lookup_page_cgroup(page);
	/* can happen while we handle swapcache. */
839
	if (!TestClearPageCgroupAcctLRU(pc))
K
KAMEZAWA Hiroyuki 已提交
840
		return;
841
	VM_BUG_ON(!pc->mem_cgroup);
842 843 844 845
	/*
	 * We don't check PCG_USED bit. It's cleared when the "page" is finally
	 * removed from global LRU.
	 */
846
	mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
847 848
	/* huge page split is done under lru_lock. so, we have no races. */
	MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page);
849 850 851
	if (mem_cgroup_is_root(pc->mem_cgroup))
		return;
	VM_BUG_ON(list_empty(&pc->lru));
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KAMEZAWA Hiroyuki 已提交
852
	list_del_init(&pc->lru);
853 854
}

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855
void mem_cgroup_del_lru(struct page *page)
856
{
K
KAMEZAWA Hiroyuki 已提交
857 858
	mem_cgroup_del_lru_list(page, page_lru(page));
}
859

860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881
/*
 * Writeback is about to end against a page which has been marked for immediate
 * reclaim.  If it still appears to be reclaimable, move it to the tail of the
 * inactive list.
 */
void mem_cgroup_rotate_reclaimable_page(struct page *page)
{
	struct mem_cgroup_per_zone *mz;
	struct page_cgroup *pc;
	enum lru_list lru = page_lru(page);

	if (mem_cgroup_disabled())
		return;

	pc = lookup_page_cgroup(page);
	/* unused or root page is not rotated. */
	if (!PageCgroupUsed(pc))
		return;
	/* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
	smp_rmb();
	if (mem_cgroup_is_root(pc->mem_cgroup))
		return;
882
	mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
883 884 885
	list_move_tail(&pc->lru, &mz->lists[lru]);
}

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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;
890

891
	if (mem_cgroup_disabled())
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892
		return;
893

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894
	pc = lookup_page_cgroup(page);
895
	/* unused or root page is not rotated. */
896 897 898 899 900
	if (!PageCgroupUsed(pc))
		return;
	/* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
	smp_rmb();
	if (mem_cgroup_is_root(pc->mem_cgroup))
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901
		return;
902
	mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
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903
	list_move(&pc->lru, &mz->lists[lru]);
904 905
}

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906
void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
907
{
K
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908 909
	struct page_cgroup *pc;
	struct mem_cgroup_per_zone *mz;
910

911
	if (mem_cgroup_disabled())
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912 913
		return;
	pc = lookup_page_cgroup(page);
914
	VM_BUG_ON(PageCgroupAcctLRU(pc));
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915
	if (!PageCgroupUsed(pc))
L
Lee Schermerhorn 已提交
916
		return;
917 918
	/* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
	smp_rmb();
919
	mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
920 921
	/* huge page split is done under lru_lock. so, we have no races. */
	MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page);
922 923 924
	SetPageCgroupAcctLRU(pc);
	if (mem_cgroup_is_root(pc->mem_cgroup))
		return;
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925 926
	list_add(&pc->lru, &mz->lists[lru]);
}
927

K
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928
/*
929 930 931 932
 * At handling SwapCache and other FUSE stuff, pc->mem_cgroup may be changed
 * while it's linked to lru because the page may be reused after it's fully
 * uncharged. To handle that, unlink page_cgroup from LRU when charge it again.
 * It's done under lock_page and expected that zone->lru_lock isnever held.
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933
 */
934
static void mem_cgroup_lru_del_before_commit(struct page *page)
K
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935
{
936 937 938 939
	unsigned long flags;
	struct zone *zone = page_zone(page);
	struct page_cgroup *pc = lookup_page_cgroup(page);

940 941 942 943 944 945 946 947 948 949 950
	/*
	 * Doing this check without taking ->lru_lock seems wrong but this
	 * is safe. Because if page_cgroup's USED bit is unset, the page
	 * will not be added to any memcg's LRU. If page_cgroup's USED bit is
	 * set, the commit after this will fail, anyway.
	 * This all charge/uncharge is done under some mutual execustion.
	 * So, we don't need to taking care of changes in USED bit.
	 */
	if (likely(!PageLRU(page)))
		return;

951 952 953 954 955 956 957 958
	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);
K
KAMEZAWA Hiroyuki 已提交
959 960
}

961
static void mem_cgroup_lru_add_after_commit(struct page *page)
962 963 964 965 966
{
	unsigned long flags;
	struct zone *zone = page_zone(page);
	struct page_cgroup *pc = lookup_page_cgroup(page);

967 968 969
	/* taking care of that the page is added to LRU while we commit it */
	if (likely(!PageLRU(page)))
		return;
970 971
	spin_lock_irqsave(&zone->lru_lock, flags);
	/* link when the page is linked to LRU but page_cgroup isn't */
972
	if (PageLRU(page) && !PageCgroupAcctLRU(pc))
973 974 975 976 977
		mem_cgroup_add_lru_list(page, page_lru(page));
	spin_unlock_irqrestore(&zone->lru_lock, flags);
}


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978 979 980
void mem_cgroup_move_lists(struct page *page,
			   enum lru_list from, enum lru_list to)
{
981
	if (mem_cgroup_disabled())
K
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982 983 984
		return;
	mem_cgroup_del_lru_list(page, from);
	mem_cgroup_add_lru_list(page, to);
985 986
}

987 988 989
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
{
	int ret;
990
	struct mem_cgroup *curr = NULL;
991
	struct task_struct *p;
992

993 994 995 996 997
	p = find_lock_task_mm(task);
	if (!p)
		return 0;
	curr = try_get_mem_cgroup_from_mm(p->mm);
	task_unlock(p);
998 999
	if (!curr)
		return 0;
1000 1001 1002 1003 1004 1005 1006
	/*
	 * 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)
1007 1008 1009 1010
		ret = css_is_ancestor(&curr->css, &mem->css);
	else
		ret = (curr == mem);
	css_put(&curr->css);
1011 1012 1013
	return ret;
}

1014
static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
1015 1016 1017
{
	unsigned long active;
	unsigned long inactive;
1018 1019
	unsigned long gb;
	unsigned long inactive_ratio;
1020

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1021 1022
	inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON);
	active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON);
1023

1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050
	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)
1051 1052 1053 1054 1055
		return 1;

	return 0;
}

1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066
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);
}

1067 1068 1069 1070
unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
				       struct zone *zone,
				       enum lru_list lru)
{
1071
	int nid = zone_to_nid(zone);
1072 1073 1074 1075 1076 1077
	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)
{
1081
	int nid = zone_to_nid(zone);
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1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097
	int zid = zone_idx(zone);
	struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);

	return &mz->reclaim_stat;
}

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

	if (mem_cgroup_disabled())
		return NULL;

	pc = lookup_page_cgroup(page);
1098 1099
	if (!PageCgroupUsed(pc))
		return NULL;
1100 1101
	/* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
	smp_rmb();
1102
	mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
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1103 1104 1105
	return &mz->reclaim_stat;
}

1106 1107 1108 1109 1110
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,
1111
					int active, int file)
1112 1113 1114 1115 1116 1117
{
	unsigned long nr_taken = 0;
	struct page *page;
	unsigned long scan;
	LIST_HEAD(pc_list);
	struct list_head *src;
1118
	struct page_cgroup *pc, *tmp;
1119
	int nid = zone_to_nid(z);
1120 1121
	int zid = zone_idx(z);
	struct mem_cgroup_per_zone *mz;
1122
	int lru = LRU_FILE * file + active;
1123
	int ret;
1124

1125
	BUG_ON(!mem_cont);
1126
	mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
1127
	src = &mz->lists[lru];
1128

1129 1130
	scan = 0;
	list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
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Hugh Dickins 已提交
1131
		if (scan >= nr_to_scan)
1132
			break;
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1133

1134 1135
		if (unlikely(!PageCgroupUsed(pc)))
			continue;
1136

1137
		page = lookup_cgroup_page(pc);
1138

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Hugh Dickins 已提交
1139
		if (unlikely(!PageLRU(page)))
1140 1141
			continue;

H
Hugh Dickins 已提交
1142
		scan++;
1143 1144 1145
		ret = __isolate_lru_page(page, mode, file);
		switch (ret) {
		case 0:
1146
			list_move(&page->lru, dst);
1147
			mem_cgroup_del_lru(page);
1148
			nr_taken += hpage_nr_pages(page);
1149 1150 1151 1152 1153 1154 1155
			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;
1156 1157 1158 1159
		}
	}

	*scanned = scan;
1160 1161 1162 1163

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

1164 1165 1166
	return nr_taken;
}

1167 1168 1169
#define mem_cgroup_from_res_counter(counter, member)	\
	container_of(counter, struct mem_cgroup, member)

1170
/**
1171 1172
 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
 * @mem: the memory cgroup
1173
 *
1174
 * Returns the maximum amount of memory @mem can be charged with, in
1175
 * pages.
1176
 */
1177
static unsigned long mem_cgroup_margin(struct mem_cgroup *mem)
1178
{
1179 1180 1181 1182 1183
	unsigned long long margin;

	margin = res_counter_margin(&mem->res);
	if (do_swap_account)
		margin = min(margin, res_counter_margin(&mem->memsw));
1184
	return margin >> PAGE_SHIFT;
1185 1186
}

K
KOSAKI Motohiro 已提交
1187 1188 1189 1190 1191 1192 1193 1194
static unsigned int get_swappiness(struct mem_cgroup *memcg)
{
	struct cgroup *cgrp = memcg->css.cgroup;

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

1195
	return memcg->swappiness;
K
KOSAKI Motohiro 已提交
1196 1197
}

1198 1199 1200
static void mem_cgroup_start_move(struct mem_cgroup *mem)
{
	int cpu;
1201 1202 1203 1204

	get_online_cpus();
	spin_lock(&mem->pcp_counter_lock);
	for_each_online_cpu(cpu)
1205
		per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1;
1206 1207 1208
	mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1;
	spin_unlock(&mem->pcp_counter_lock);
	put_online_cpus();
1209 1210 1211 1212 1213 1214 1215 1216 1217 1218

	synchronize_rcu();
}

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

	if (!mem)
		return;
1219 1220 1221
	get_online_cpus();
	spin_lock(&mem->pcp_counter_lock);
	for_each_online_cpu(cpu)
1222
		per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1;
1223 1224 1225
	mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1;
	spin_unlock(&mem->pcp_counter_lock);
	put_online_cpus();
1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243
}
/*
 * 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;
}
1244 1245 1246

static bool mem_cgroup_under_move(struct mem_cgroup *mem)
{
1247 1248
	struct mem_cgroup *from;
	struct mem_cgroup *to;
1249
	bool ret = false;
1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264
	/*
	 * 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);
1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283
	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;
}

1284
/**
1285
 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303
 * @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;

1304
	if (!memcg || !p)
1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350
		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));
}

1351 1352 1353 1354 1355 1356 1357
/*
 * 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;
K
KAMEZAWA Hiroyuki 已提交
1358 1359 1360 1361
	struct mem_cgroup *iter;

	for_each_mem_cgroup_tree(iter, mem)
		num++;
1362 1363 1364
	return num;
}

D
David Rientjes 已提交
1365 1366 1367 1368 1369 1370 1371 1372
/*
 * Return the memory (and swap, if configured) limit for a memcg.
 */
u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
{
	u64 limit;
	u64 memsw;

1373 1374 1375
	limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
	limit += total_swap_pages << PAGE_SHIFT;

D
David Rientjes 已提交
1376 1377 1378 1379 1380 1381 1382 1383
	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);
}

1384
/*
K
KAMEZAWA Hiroyuki 已提交
1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424
 * 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 */
		if (!css) {
			/* this means start scan from ID:1 */
			root_mem->last_scanned_child = 0;
		} else
			root_mem->last_scanned_child = found;
	}

	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.
1425 1426
 *
 * root_mem is the original ancestor that we've been reclaim from.
K
KAMEZAWA Hiroyuki 已提交
1427 1428 1429
 *
 * We give up and return to the caller when we visit root_mem twice.
 * (other groups can be removed while we're walking....)
1430 1431
 *
 * If shrink==true, for avoiding to free too much, this returns immedieately.
1432 1433
 */
static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
1434
						struct zone *zone,
1435
						gfp_t gfp_mask,
1436 1437
						unsigned long reclaim_options,
						unsigned long *total_scanned)
1438
{
K
KAMEZAWA Hiroyuki 已提交
1439 1440 1441
	struct mem_cgroup *victim;
	int ret, total = 0;
	int loop = 0;
1442 1443
	bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
	bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
1444
	bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
1445
	unsigned long excess;
1446
	unsigned long nr_scanned;
1447 1448

	excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT;
K
KAMEZAWA Hiroyuki 已提交
1449

1450 1451 1452 1453
	/* If memsw_is_minimum==1, swap-out is of-no-use. */
	if (root_mem->memsw_is_minimum)
		noswap = true;

1454
	while (1) {
K
KAMEZAWA Hiroyuki 已提交
1455
		victim = mem_cgroup_select_victim(root_mem);
1456
		if (victim == root_mem) {
K
KAMEZAWA Hiroyuki 已提交
1457
			loop++;
1458 1459
			if (loop >= 1)
				drain_all_stock_async();
1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470
			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;
				}
				/*
L
Lucas De Marchi 已提交
1471
				 * We want to do more targeted reclaim.
1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482
				 * 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;
				}
			}
		}
1483
		if (!mem_cgroup_local_usage(victim)) {
K
KAMEZAWA Hiroyuki 已提交
1484 1485
			/* this cgroup's local usage == 0 */
			css_put(&victim->css);
1486 1487
			continue;
		}
K
KAMEZAWA Hiroyuki 已提交
1488
		/* we use swappiness of local cgroup */
1489
		if (check_soft) {
1490
			ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
1491 1492 1493 1494
				noswap, get_swappiness(victim), zone,
				&nr_scanned);
			*total_scanned += nr_scanned;
		} else
1495 1496
			ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
						noswap, get_swappiness(victim));
K
KAMEZAWA Hiroyuki 已提交
1497
		css_put(&victim->css);
1498 1499 1500 1501 1502 1503 1504
		/*
		 * 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
1505
		total += ret;
1506
		if (check_soft) {
1507
			if (!res_counter_soft_limit_excess(&root_mem->res))
1508
				return total;
1509
		} else if (mem_cgroup_margin(root_mem))
K
KAMEZAWA Hiroyuki 已提交
1510
			return 1 + total;
1511
	}
K
KAMEZAWA Hiroyuki 已提交
1512
	return total;
1513 1514
}

K
KAMEZAWA Hiroyuki 已提交
1515 1516 1517 1518 1519 1520
/*
 * 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
1521 1522
	int x, lock_count = 0;
	struct mem_cgroup *iter;
1523

K
KAMEZAWA Hiroyuki 已提交
1524 1525 1526 1527
	for_each_mem_cgroup_tree(iter, mem) {
		x = atomic_inc_return(&iter->oom_lock);
		lock_count = max(x, lock_count);
	}
K
KAMEZAWA Hiroyuki 已提交
1528 1529 1530 1531

	if (lock_count == 1)
		return true;
	return false;
1532
}
1533

K
KAMEZAWA Hiroyuki 已提交
1534
static int mem_cgroup_oom_unlock(struct mem_cgroup *mem)
1535
{
K
KAMEZAWA Hiroyuki 已提交
1536 1537
	struct mem_cgroup *iter;

K
KAMEZAWA Hiroyuki 已提交
1538 1539 1540 1541 1542
	/*
	 * 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
1543 1544
	for_each_mem_cgroup_tree(iter, mem)
		atomic_add_unless(&iter->oom_lock, -1, 0);
1545 1546 1547
	return 0;
}

K
KAMEZAWA Hiroyuki 已提交
1548 1549 1550 1551

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

K
KAMEZAWA Hiroyuki 已提交
1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587
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);
}

1588 1589
static void memcg_oom_recover(struct mem_cgroup *mem)
{
1590
	if (mem && atomic_read(&mem->oom_lock))
1591 1592 1593
		memcg_wakeup_oom(mem);
}

K
KAMEZAWA Hiroyuki 已提交
1594 1595 1596 1597
/*
 * 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)
1598
{
K
KAMEZAWA Hiroyuki 已提交
1599
	struct oom_wait_info owait;
1600
	bool locked, need_to_kill;
K
KAMEZAWA Hiroyuki 已提交
1601

K
KAMEZAWA Hiroyuki 已提交
1602 1603 1604 1605 1606
	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);
1607
	need_to_kill = true;
K
KAMEZAWA Hiroyuki 已提交
1608 1609 1610 1611 1612 1613 1614 1615
	/* 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.
	 */
1616 1617 1618 1619
	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
1620
		mem_cgroup_oom_notify(mem);
K
KAMEZAWA Hiroyuki 已提交
1621 1622
	mutex_unlock(&memcg_oom_mutex);

1623 1624
	if (need_to_kill) {
		finish_wait(&memcg_oom_waitq, &owait.wait);
K
KAMEZAWA Hiroyuki 已提交
1625
		mem_cgroup_out_of_memory(mem, mask);
1626
	} else {
K
KAMEZAWA Hiroyuki 已提交
1627
		schedule();
K
KAMEZAWA Hiroyuki 已提交
1628
		finish_wait(&memcg_oom_waitq, &owait.wait);
K
KAMEZAWA Hiroyuki 已提交
1629 1630 1631
	}
	mutex_lock(&memcg_oom_mutex);
	mem_cgroup_oom_unlock(mem);
K
KAMEZAWA Hiroyuki 已提交
1632
	memcg_wakeup_oom(mem);
K
KAMEZAWA Hiroyuki 已提交
1633 1634 1635 1636 1637 1638 1639
	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;
1640 1641
}

1642 1643 1644
/*
 * Currently used to update mapped file statistics, but the routine can be
 * generalized to update other statistics as well.
1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663
 *
 * 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.
1664
 */
1665

1666 1667
void mem_cgroup_update_page_stat(struct page *page,
				 enum mem_cgroup_page_stat_item idx, int val)
1668 1669
{
	struct mem_cgroup *mem;
1670 1671
	struct page_cgroup *pc = lookup_page_cgroup(page);
	bool need_unlock = false;
1672
	unsigned long uninitialized_var(flags);
1673 1674 1675 1676

	if (unlikely(!pc))
		return;

1677
	rcu_read_lock();
1678
	mem = pc->mem_cgroup;
1679 1680 1681
	if (unlikely(!mem || !PageCgroupUsed(pc)))
		goto out;
	/* pc->mem_cgroup is unstable ? */
1682
	if (unlikely(mem_cgroup_stealed(mem)) || PageTransHuge(page)) {
1683
		/* take a lock against to access pc->mem_cgroup */
1684
		move_lock_page_cgroup(pc, &flags);
1685 1686 1687 1688 1689
		need_unlock = true;
		mem = pc->mem_cgroup;
		if (!mem || !PageCgroupUsed(pc))
			goto out;
	}
1690 1691

	switch (idx) {
1692
	case MEMCG_NR_FILE_MAPPED:
1693 1694 1695
		if (val > 0)
			SetPageCgroupFileMapped(pc);
		else if (!page_mapped(page))
1696
			ClearPageCgroupFileMapped(pc);
1697
		idx = MEM_CGROUP_STAT_FILE_MAPPED;
1698 1699 1700
		break;
	default:
		BUG();
1701
	}
1702

1703 1704
	this_cpu_add(mem->stat->count[idx], val);

1705 1706
out:
	if (unlikely(need_unlock))
1707
		move_unlock_page_cgroup(pc, &flags);
1708 1709
	rcu_read_unlock();
	return;
1710
}
1711
EXPORT_SYMBOL(mem_cgroup_update_page_stat);
1712

1713 1714 1715 1716
/*
 * size of first charge trial. "32" comes from vmscan.c's magic value.
 * TODO: maybe necessary to use big numbers in big irons.
 */
1717
#define CHARGE_BATCH	32U
1718 1719
struct memcg_stock_pcp {
	struct mem_cgroup *cached; /* this never be root cgroup */
1720
	unsigned int nr_pages;
1721 1722 1723 1724 1725 1726
	struct work_struct work;
};
static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
static atomic_t memcg_drain_count;

/*
1727
 * Try to consume stocked charge on this cpu. If success, one page is consumed
1728 1729 1730 1731 1732 1733 1734 1735 1736 1737
 * 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);
1738 1739
	if (mem == stock->cached && stock->nr_pages)
		stock->nr_pages--;
1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752
	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;

1753 1754 1755 1756
	if (stock->nr_pages) {
		unsigned long bytes = stock->nr_pages * PAGE_SIZE;

		res_counter_uncharge(&old->res, bytes);
1757
		if (do_swap_account)
1758 1759
			res_counter_uncharge(&old->memsw, bytes);
		stock->nr_pages = 0;
1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775
	}
	stock->cached = NULL;
}

/*
 * This must be called under preempt disabled or must be called by
 * a thread which is pinned to local cpu.
 */
static void drain_local_stock(struct work_struct *dummy)
{
	struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock);
	drain_stock(stock);
}

/*
 * Cache charges(val) which is from res_counter, to local per_cpu area.
1776
 * This will be consumed by consume_stock() function, later.
1777
 */
1778
static void refill_stock(struct mem_cgroup *mem, unsigned int nr_pages)
1779 1780 1781 1782 1783 1784 1785
{
	struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);

	if (stock->cached != mem) { /* reset if necessary */
		drain_stock(stock);
		stock->cached = mem;
	}
1786
	stock->nr_pages += nr_pages;
1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827
	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);
}

1828 1829 1830 1831 1832 1833 1834 1835 1836 1837
/*
 * 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++) {
1838
		long x = per_cpu(mem->stat->count[i], cpu);
1839 1840 1841 1842

		per_cpu(mem->stat->count[i], cpu) = 0;
		mem->nocpu_base.count[i] += x;
	}
1843 1844 1845 1846 1847 1848
	for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
		unsigned long x = per_cpu(mem->stat->events[i], cpu);

		per_cpu(mem->stat->events[i], cpu) = 0;
		mem->nocpu_base.events[i] += x;
	}
1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859
	/* 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];
1860 1861 1862 1863
	spin_unlock(&mem->pcp_counter_lock);
}

static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
1864 1865 1866 1867 1868
					unsigned long action,
					void *hcpu)
{
	int cpu = (unsigned long)hcpu;
	struct memcg_stock_pcp *stock;
1869
	struct mem_cgroup *iter;
1870

1871 1872 1873 1874 1875 1876
	if ((action == CPU_ONLINE)) {
		for_each_mem_cgroup_all(iter)
			synchronize_mem_cgroup_on_move(iter, cpu);
		return NOTIFY_OK;
	}

1877
	if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN)
1878
		return NOTIFY_OK;
1879 1880 1881 1882

	for_each_mem_cgroup_all(iter)
		mem_cgroup_drain_pcp_counter(iter, cpu);

1883 1884 1885 1886 1887
	stock = &per_cpu(memcg_stock, cpu);
	drain_stock(stock);
	return NOTIFY_OK;
}

1888 1889 1890 1891 1892 1893 1894 1895 1896 1897

/* 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 */
};

1898 1899
static int mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask,
				unsigned int nr_pages, bool oom_check)
1900
{
1901
	unsigned long csize = nr_pages * PAGE_SIZE;
1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915
	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;

1916
		res_counter_uncharge(&mem->res, csize);
1917 1918 1919 1920
		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);
1921
	/*
1922 1923
	 * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch
	 * of regular pages (CHARGE_BATCH), or a single regular page (1).
1924 1925 1926 1927
	 *
	 * Never reclaim on behalf of optional batching, retry with a
	 * single page instead.
	 */
1928
	if (nr_pages == CHARGE_BATCH)
1929 1930 1931 1932 1933 1934
		return CHARGE_RETRY;

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

	ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
1935
					      gfp_mask, flags, NULL);
1936
	if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
1937
		return CHARGE_RETRY;
1938
	/*
1939 1940 1941 1942 1943 1944 1945
	 * Even though the limit is exceeded at this point, reclaim
	 * may have been able to free some pages.  Retry the charge
	 * before killing the task.
	 *
	 * Only for regular pages, though: huge pages are rather
	 * unlikely to succeed so close to the limit, and we fall back
	 * to regular pages anyway in case of failure.
1946
	 */
1947
	if (nr_pages == 1 && ret)
1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966
		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;
}

1967 1968 1969
/*
 * Unlike exported interface, "oom" parameter is added. if oom==true,
 * oom-killer can be invoked.
1970
 */
1971
static int __mem_cgroup_try_charge(struct mm_struct *mm,
A
Andrea Arcangeli 已提交
1972
				   gfp_t gfp_mask,
1973 1974 1975
				   unsigned int nr_pages,
				   struct mem_cgroup **memcg,
				   bool oom)
1976
{
1977
	unsigned int batch = max(CHARGE_BATCH, nr_pages);
1978 1979 1980
	int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
	struct mem_cgroup *mem = NULL;
	int ret;
1981

K
KAMEZAWA Hiroyuki 已提交
1982 1983 1984 1985 1986 1987 1988 1989
	/*
	 * 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;
1990

1991
	/*
1992 1993
	 * We always charge the cgroup the mm_struct belongs to.
	 * The mm_struct's mem_cgroup changes on task migration if the
1994 1995 1996
	 * 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
1997 1998 1999 2000
	if (!*memcg && !mm)
		goto bypass;
again:
	if (*memcg) { /* css should be a valid one */
2001
		mem = *memcg;
K
KAMEZAWA Hiroyuki 已提交
2002 2003 2004
		VM_BUG_ON(css_is_removed(&mem->css));
		if (mem_cgroup_is_root(mem))
			goto done;
2005
		if (nr_pages == 1 && consume_stock(mem))
K
KAMEZAWA Hiroyuki 已提交
2006
			goto done;
2007 2008
		css_get(&mem->css);
	} else {
K
KAMEZAWA Hiroyuki 已提交
2009
		struct task_struct *p;
2010

K
KAMEZAWA Hiroyuki 已提交
2011 2012 2013
		rcu_read_lock();
		p = rcu_dereference(mm->owner);
		/*
2014 2015 2016 2017 2018 2019 2020 2021
		 * 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
2022 2023
		 */
		mem = mem_cgroup_from_task(p);
2024
		if (!mem || mem_cgroup_is_root(mem)) {
K
KAMEZAWA Hiroyuki 已提交
2025 2026 2027
			rcu_read_unlock();
			goto done;
		}
2028
		if (nr_pages == 1 && consume_stock(mem)) {
K
KAMEZAWA Hiroyuki 已提交
2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046
			/*
			 * 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();
	}
2047

2048 2049
	do {
		bool oom_check;
2050

2051
		/* If killed, bypass charge */
K
KAMEZAWA Hiroyuki 已提交
2052 2053
		if (fatal_signal_pending(current)) {
			css_put(&mem->css);
2054
			goto bypass;
K
KAMEZAWA Hiroyuki 已提交
2055
		}
2056

2057 2058 2059 2060
		oom_check = false;
		if (oom && !nr_oom_retries) {
			oom_check = true;
			nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2061
		}
2062

2063
		ret = mem_cgroup_do_charge(mem, gfp_mask, batch, oom_check);
2064 2065 2066 2067
		switch (ret) {
		case CHARGE_OK:
			break;
		case CHARGE_RETRY: /* not in OOM situation but retry */
2068
			batch = nr_pages;
K
KAMEZAWA Hiroyuki 已提交
2069 2070 2071
			css_put(&mem->css);
			mem = NULL;
			goto again;
2072
		case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
K
KAMEZAWA Hiroyuki 已提交
2073
			css_put(&mem->css);
2074 2075
			goto nomem;
		case CHARGE_NOMEM: /* OOM routine works */
K
KAMEZAWA Hiroyuki 已提交
2076 2077
			if (!oom) {
				css_put(&mem->css);
K
KAMEZAWA Hiroyuki 已提交
2078
				goto nomem;
K
KAMEZAWA Hiroyuki 已提交
2079
			}
2080 2081 2082 2083
			/* If oom, we never return -ENOMEM */
			nr_oom_retries--;
			break;
		case CHARGE_OOM_DIE: /* Killed by OOM Killer */
K
KAMEZAWA Hiroyuki 已提交
2084
			css_put(&mem->css);
K
KAMEZAWA Hiroyuki 已提交
2085
			goto bypass;
2086
		}
2087 2088
	} while (ret != CHARGE_OK);

2089 2090
	if (batch > nr_pages)
		refill_stock(mem, batch - nr_pages);
K
KAMEZAWA Hiroyuki 已提交
2091
	css_put(&mem->css);
2092
done:
K
KAMEZAWA Hiroyuki 已提交
2093
	*memcg = mem;
2094 2095
	return 0;
nomem:
K
KAMEZAWA Hiroyuki 已提交
2096
	*memcg = NULL;
2097
	return -ENOMEM;
K
KAMEZAWA Hiroyuki 已提交
2098 2099 2100
bypass:
	*memcg = NULL;
	return 0;
2101
}
2102

2103 2104 2105 2106 2107
/*
 * 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().
 */
2108
static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem,
2109
				       unsigned int nr_pages)
2110 2111
{
	if (!mem_cgroup_is_root(mem)) {
2112 2113 2114
		unsigned long bytes = nr_pages * PAGE_SIZE;

		res_counter_uncharge(&mem->res, bytes);
2115
		if (do_swap_account)
2116
			res_counter_uncharge(&mem->memsw, bytes);
2117
	}
2118 2119
}

2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138
/*
 * 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);
}

2139
struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2140
{
2141
	struct mem_cgroup *mem = NULL;
2142
	struct page_cgroup *pc;
2143
	unsigned short id;
2144 2145
	swp_entry_t ent;

2146 2147 2148
	VM_BUG_ON(!PageLocked(page));

	pc = lookup_page_cgroup(page);
2149
	lock_page_cgroup(pc);
2150
	if (PageCgroupUsed(pc)) {
2151
		mem = pc->mem_cgroup;
2152 2153
		if (mem && !css_tryget(&mem->css))
			mem = NULL;
2154
	} else if (PageSwapCache(page)) {
2155
		ent.val = page_private(page);
2156 2157 2158 2159 2160 2161
		id = lookup_swap_cgroup(ent);
		rcu_read_lock();
		mem = mem_cgroup_lookup(id);
		if (mem && !css_tryget(&mem->css))
			mem = NULL;
		rcu_read_unlock();
2162
	}
2163
	unlock_page_cgroup(pc);
2164 2165 2166
	return mem;
}

2167
static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
2168
				       struct page *page,
2169
				       unsigned int nr_pages,
2170
				       struct page_cgroup *pc,
2171
				       enum charge_type ctype)
2172
{
2173 2174 2175
	lock_page_cgroup(pc);
	if (unlikely(PageCgroupUsed(pc))) {
		unlock_page_cgroup(pc);
2176
		__mem_cgroup_cancel_charge(mem, nr_pages);
2177 2178 2179 2180 2181 2182
		return;
	}
	/*
	 * we don't need page_cgroup_lock about tail pages, becase they are not
	 * accessed by any other context at this point.
	 */
2183
	pc->mem_cgroup = mem;
2184 2185 2186 2187 2188 2189 2190
	/*
	 * 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
2191
	smp_wmb();
2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204
	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;
	}
2205

2206
	mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), nr_pages);
2207
	unlock_page_cgroup(pc);
2208 2209 2210 2211 2212
	/*
	 * "charge_statistics" updated event counter. Then, check it.
	 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
	 * if they exceeds softlimit.
	 */
2213
	memcg_check_events(mem, page);
2214
}
2215

2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229
#ifdef CONFIG_TRANSPARENT_HUGEPAGE

#define PCGF_NOCOPY_AT_SPLIT ((1 << PCG_LOCK) | (1 << PCG_MOVE_LOCK) |\
			(1 << PCG_ACCT_LRU) | (1 << PCG_MIGRATION))
/*
 * Because tail pages are not marked as "used", set it. We're under
 * zone->lru_lock, 'splitting on pmd' and compund_lock.
 */
void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail)
{
	struct page_cgroup *head_pc = lookup_page_cgroup(head);
	struct page_cgroup *tail_pc = lookup_page_cgroup(tail);
	unsigned long flags;

2230 2231
	if (mem_cgroup_disabled())
		return;
2232
	/*
2233
	 * We have no races with charge/uncharge but will have races with
2234 2235 2236 2237 2238 2239
	 * page state accounting.
	 */
	move_lock_page_cgroup(head_pc, &flags);

	tail_pc->mem_cgroup = head_pc->mem_cgroup;
	smp_wmb(); /* see __commit_charge() */
2240 2241 2242 2243 2244 2245 2246 2247 2248 2249
	if (PageCgroupAcctLRU(head_pc)) {
		enum lru_list lru;
		struct mem_cgroup_per_zone *mz;

		/*
		 * LRU flags cannot be copied because we need to add tail
		 *.page to LRU by generic call and our hook will be called.
		 * We hold lru_lock, then, reduce counter directly.
		 */
		lru = page_lru(head);
2250
		mz = page_cgroup_zoneinfo(head_pc->mem_cgroup, head);
2251 2252
		MEM_CGROUP_ZSTAT(mz, lru) -= 1;
	}
2253 2254 2255 2256 2257
	tail_pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
	move_unlock_page_cgroup(head_pc, &flags);
}
#endif

2258
/**
2259
 * mem_cgroup_move_account - move account of the page
2260
 * @page: the page
2261
 * @nr_pages: number of regular pages (>1 for huge pages)
2262 2263 2264
 * @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.
2265
 * @uncharge: whether we should call uncharge and css_put against @from.
2266 2267
 *
 * The caller must confirm following.
K
KAMEZAWA Hiroyuki 已提交
2268
 * - page is not on LRU (isolate_page() is useful.)
2269
 * - compound_lock is held when nr_pages > 1
2270
 *
2271
 * This function doesn't do "charge" nor css_get to new cgroup. It should be
L
Lucas De Marchi 已提交
2272
 * done by a caller(__mem_cgroup_try_charge would be useful). If @uncharge is
2273 2274
 * true, this function does "uncharge" from old cgroup, but it doesn't if
 * @uncharge is false, so a caller should do "uncharge".
2275
 */
2276 2277 2278 2279 2280 2281
static int mem_cgroup_move_account(struct page *page,
				   unsigned int nr_pages,
				   struct page_cgroup *pc,
				   struct mem_cgroup *from,
				   struct mem_cgroup *to,
				   bool uncharge)
2282
{
2283 2284
	unsigned long flags;
	int ret;
2285

2286
	VM_BUG_ON(from == to);
2287
	VM_BUG_ON(PageLRU(page));
2288 2289 2290 2291 2292 2293 2294
	/*
	 * The page is isolated from LRU. So, collapse function
	 * will not handle this page. But page splitting can happen.
	 * Do this check under compound_page_lock(). The caller should
	 * hold it.
	 */
	ret = -EBUSY;
2295
	if (nr_pages > 1 && !PageTransHuge(page))
2296 2297 2298 2299 2300 2301 2302 2303 2304
		goto out;

	lock_page_cgroup(pc);

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

	move_lock_page_cgroup(pc, &flags);
2305

2306
	if (PageCgroupFileMapped(pc)) {
2307 2308 2309 2310 2311
		/* 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();
2312
	}
2313
	mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages);
2314 2315
	if (uncharge)
		/* This is not "cancel", but cancel_charge does all we need. */
2316
		__mem_cgroup_cancel_charge(from, nr_pages);
2317

2318
	/* caller should have done css_get */
K
KAMEZAWA Hiroyuki 已提交
2319
	pc->mem_cgroup = to;
2320
	mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages);
2321 2322 2323
	/*
	 * We charges against "to" which may not have any tasks. Then, "to"
	 * can be under rmdir(). But in current implementation, caller of
2324
	 * this function is just force_empty() and move charge, so it's
L
Lucas De Marchi 已提交
2325
	 * guaranteed that "to" is never removed. So, we don't check rmdir
2326
	 * status here.
2327
	 */
2328 2329 2330
	move_unlock_page_cgroup(pc, &flags);
	ret = 0;
unlock:
2331
	unlock_page_cgroup(pc);
2332 2333 2334
	/*
	 * check events
	 */
2335 2336
	memcg_check_events(to, page);
	memcg_check_events(from, page);
2337
out:
2338 2339 2340 2341 2342 2343 2344
	return ret;
}

/*
 * move charges to its parent.
 */

2345 2346
static int mem_cgroup_move_parent(struct page *page,
				  struct page_cgroup *pc,
2347 2348 2349 2350 2351 2352
				  struct mem_cgroup *child,
				  gfp_t gfp_mask)
{
	struct cgroup *cg = child->css.cgroup;
	struct cgroup *pcg = cg->parent;
	struct mem_cgroup *parent;
2353
	unsigned int nr_pages;
2354
	unsigned long uninitialized_var(flags);
2355 2356 2357 2358 2359 2360
	int ret;

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

2361 2362 2363 2364 2365
	ret = -EBUSY;
	if (!get_page_unless_zero(page))
		goto out;
	if (isolate_lru_page(page))
		goto put;
2366

2367
	nr_pages = hpage_nr_pages(page);
K
KAMEZAWA Hiroyuki 已提交
2368

2369
	parent = mem_cgroup_from_cont(pcg);
2370
	ret = __mem_cgroup_try_charge(NULL, gfp_mask, nr_pages, &parent, false);
2371
	if (ret || !parent)
2372
		goto put_back;
2373

2374
	if (nr_pages > 1)
2375 2376
		flags = compound_lock_irqsave(page);

2377
	ret = mem_cgroup_move_account(page, nr_pages, pc, child, parent, true);
2378
	if (ret)
2379
		__mem_cgroup_cancel_charge(parent, nr_pages);
2380

2381
	if (nr_pages > 1)
2382
		compound_unlock_irqrestore(page, flags);
2383
put_back:
K
KAMEZAWA Hiroyuki 已提交
2384
	putback_lru_page(page);
2385
put:
2386
	put_page(page);
2387
out:
2388 2389 2390
	return ret;
}

2391 2392 2393 2394 2395 2396 2397
/*
 * 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,
2398
				gfp_t gfp_mask, enum charge_type ctype)
2399
{
2400
	struct mem_cgroup *mem = NULL;
2401
	unsigned int nr_pages = 1;
2402
	struct page_cgroup *pc;
2403
	bool oom = true;
2404
	int ret;
A
Andrea Arcangeli 已提交
2405

A
Andrea Arcangeli 已提交
2406
	if (PageTransHuge(page)) {
2407
		nr_pages <<= compound_order(page);
A
Andrea Arcangeli 已提交
2408
		VM_BUG_ON(!PageTransHuge(page));
2409 2410 2411 2412 2413
		/*
		 * Never OOM-kill a process for a huge page.  The
		 * fault handler will fall back to regular pages.
		 */
		oom = false;
A
Andrea Arcangeli 已提交
2414
	}
2415 2416

	pc = lookup_page_cgroup(page);
2417
	BUG_ON(!pc); /* XXX: remove this and move pc lookup into commit */
2418

2419
	ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &mem, oom);
2420
	if (ret || !mem)
2421 2422
		return ret;

2423
	__mem_cgroup_commit_charge(mem, page, nr_pages, pc, ctype);
2424 2425 2426
	return 0;
}

2427 2428
int mem_cgroup_newpage_charge(struct page *page,
			      struct mm_struct *mm, gfp_t gfp_mask)
2429
{
2430
	if (mem_cgroup_disabled())
2431
		return 0;
2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442
	/*
	 * 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;
2443
	return mem_cgroup_charge_common(page, mm, gfp_mask,
2444
				MEM_CGROUP_CHARGE_TYPE_MAPPED);
2445 2446
}

D
Daisuke Nishimura 已提交
2447 2448 2449 2450
static void
__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
					enum charge_type ctype);

2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466
static void
__mem_cgroup_commit_charge_lrucare(struct page *page, struct mem_cgroup *mem,
					enum charge_type ctype)
{
	struct page_cgroup *pc = lookup_page_cgroup(page);
	/*
	 * In some case, SwapCache, FUSE(splice_buf->radixtree), the page
	 * is already on LRU. It means the page may on some other page_cgroup's
	 * LRU. Take care of it.
	 */
	mem_cgroup_lru_del_before_commit(page);
	__mem_cgroup_commit_charge(mem, page, 1, pc, ctype);
	mem_cgroup_lru_add_after_commit(page);
	return;
}

2467 2468
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
				gfp_t gfp_mask)
2469
{
2470
	struct mem_cgroup *mem = NULL;
2471 2472
	int ret;

2473
	if (mem_cgroup_disabled())
2474
		return 0;
2475 2476
	if (PageCompound(page))
		return 0;
2477 2478 2479 2480 2481 2482 2483 2484
	/*
	 * 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.)
2485 2486
	 * And when the page is SwapCache, it should take swap information
	 * into account. This is under lock_page() now.
2487 2488 2489 2490
	 */
	if (!(gfp_mask & __GFP_WAIT)) {
		struct page_cgroup *pc;

2491 2492 2493 2494 2495 2496
		pc = lookup_page_cgroup(page);
		if (!pc)
			return 0;
		lock_page_cgroup(pc);
		if (PageCgroupUsed(pc)) {
			unlock_page_cgroup(pc);
2497 2498
			return 0;
		}
2499
		unlock_page_cgroup(pc);
2500 2501
	}

2502
	if (unlikely(!mm))
2503
		mm = &init_mm;
2504

2505 2506 2507 2508
	if (page_is_file_cache(page)) {
		ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, &mem, true);
		if (ret || !mem)
			return ret;
2509

2510 2511 2512 2513 2514 2515 2516 2517 2518
		/*
		 * FUSE reuses pages without going through the final
		 * put that would remove them from the LRU list, make
		 * sure that they get relinked properly.
		 */
		__mem_cgroup_commit_charge_lrucare(page, mem,
					MEM_CGROUP_CHARGE_TYPE_CACHE);
		return ret;
	}
D
Daisuke Nishimura 已提交
2519 2520 2521 2522 2523 2524 2525 2526
	/* shmem */
	if (PageSwapCache(page)) {
		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,
2527
					MEM_CGROUP_CHARGE_TYPE_SHMEM);
2528 2529

	return ret;
2530 2531
}

2532 2533 2534
/*
 * While swap-in, try_charge -> commit or cancel, the page is locked.
 * And when try_charge() successfully returns, one refcnt to memcg without
2535
 * struct page_cgroup is acquired. This refcnt will be consumed by
2536 2537
 * "commit()" or removed by "cancel()"
 */
2538 2539 2540 2541 2542
int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
				 struct page *page,
				 gfp_t mask, struct mem_cgroup **ptr)
{
	struct mem_cgroup *mem;
2543
	int ret;
2544

2545 2546
	*ptr = NULL;

2547
	if (mem_cgroup_disabled())
2548 2549 2550 2551 2552 2553
		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
2554 2555 2556
	 * 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.
2557 2558
	 */
	if (!PageSwapCache(page))
H
Hugh Dickins 已提交
2559
		goto charge_cur_mm;
2560
	mem = try_get_mem_cgroup_from_page(page);
2561 2562
	if (!mem)
		goto charge_cur_mm;
2563
	*ptr = mem;
2564
	ret = __mem_cgroup_try_charge(NULL, mask, 1, ptr, true);
2565 2566
	css_put(&mem->css);
	return ret;
2567 2568 2569
charge_cur_mm:
	if (unlikely(!mm))
		mm = &init_mm;
2570
	return __mem_cgroup_try_charge(mm, mask, 1, ptr, true);
2571 2572
}

D
Daisuke Nishimura 已提交
2573 2574 2575
static void
__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
					enum charge_type ctype)
2576
{
2577
	if (mem_cgroup_disabled())
2578 2579 2580
		return;
	if (!ptr)
		return;
2581
	cgroup_exclude_rmdir(&ptr->css);
2582 2583

	__mem_cgroup_commit_charge_lrucare(page, ptr, ctype);
2584 2585 2586
	/*
	 * Now swap is on-memory. This means this page may be
	 * counted both as mem and swap....double count.
2587 2588 2589
	 * 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.
2590
	 */
2591
	if (do_swap_account && PageSwapCache(page)) {
2592
		swp_entry_t ent = {.val = page_private(page)};
2593
		unsigned short id;
2594
		struct mem_cgroup *memcg;
2595 2596 2597 2598

		id = swap_cgroup_record(ent, 0);
		rcu_read_lock();
		memcg = mem_cgroup_lookup(id);
2599
		if (memcg) {
2600 2601 2602 2603
			/*
			 * This recorded memcg can be obsolete one. So, avoid
			 * calling css_tryget
			 */
2604
			if (!mem_cgroup_is_root(memcg))
2605
				res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2606
			mem_cgroup_swap_statistics(memcg, false);
2607 2608
			mem_cgroup_put(memcg);
		}
2609
		rcu_read_unlock();
2610
	}
2611 2612 2613 2614 2615 2616
	/*
	 * 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);
2617 2618
}

D
Daisuke Nishimura 已提交
2619 2620 2621 2622 2623 2624
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);
}

2625 2626
void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
{
2627
	if (mem_cgroup_disabled())
2628 2629 2630
		return;
	if (!mem)
		return;
2631
	__mem_cgroup_cancel_charge(mem, 1);
2632 2633
}

2634 2635 2636
static void mem_cgroup_do_uncharge(struct mem_cgroup *mem,
				   unsigned int nr_pages,
				   const enum charge_type ctype)
2637 2638 2639
{
	struct memcg_batch_info *batch = NULL;
	bool uncharge_memsw = true;
2640

2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652
	/* 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;
2653 2654
	/*
	 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
L
Lucas De Marchi 已提交
2655
	 * In those cases, all pages freed continuously can be expected to be in
2656 2657 2658 2659 2660 2661 2662 2663
	 * 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;

2664
	if (nr_pages > 1)
A
Andrea Arcangeli 已提交
2665 2666
		goto direct_uncharge;

2667 2668 2669 2670 2671 2672 2673 2674
	/*
	 * 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 */
2675
	batch->nr_pages++;
2676
	if (uncharge_memsw)
2677
		batch->memsw_nr_pages++;
2678 2679
	return;
direct_uncharge:
2680
	res_counter_uncharge(&mem->res, nr_pages * PAGE_SIZE);
2681
	if (uncharge_memsw)
2682
		res_counter_uncharge(&mem->memsw, nr_pages * PAGE_SIZE);
2683 2684
	if (unlikely(batch->memcg != mem))
		memcg_oom_recover(mem);
2685 2686
	return;
}
2687

2688
/*
2689
 * uncharge if !page_mapped(page)
2690
 */
2691
static struct mem_cgroup *
2692
__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
2693
{
2694
	struct mem_cgroup *mem = NULL;
2695 2696
	unsigned int nr_pages = 1;
	struct page_cgroup *pc;
2697

2698
	if (mem_cgroup_disabled())
2699
		return NULL;
2700

K
KAMEZAWA Hiroyuki 已提交
2701
	if (PageSwapCache(page))
2702
		return NULL;
K
KAMEZAWA Hiroyuki 已提交
2703

A
Andrea Arcangeli 已提交
2704
	if (PageTransHuge(page)) {
2705
		nr_pages <<= compound_order(page);
A
Andrea Arcangeli 已提交
2706 2707
		VM_BUG_ON(!PageTransHuge(page));
	}
2708
	/*
2709
	 * Check if our page_cgroup is valid
2710
	 */
2711 2712
	pc = lookup_page_cgroup(page);
	if (unlikely(!pc || !PageCgroupUsed(pc)))
2713
		return NULL;
2714

2715
	lock_page_cgroup(pc);
K
KAMEZAWA Hiroyuki 已提交
2716

2717 2718
	mem = pc->mem_cgroup;

K
KAMEZAWA Hiroyuki 已提交
2719 2720 2721 2722 2723
	if (!PageCgroupUsed(pc))
		goto unlock_out;

	switch (ctype) {
	case MEM_CGROUP_CHARGE_TYPE_MAPPED:
K
KAMEZAWA Hiroyuki 已提交
2724
	case MEM_CGROUP_CHARGE_TYPE_DROP:
2725 2726
		/* See mem_cgroup_prepare_migration() */
		if (page_mapped(page) || PageCgroupMigration(pc))
K
KAMEZAWA Hiroyuki 已提交
2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737
			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;
2738
	}
K
KAMEZAWA Hiroyuki 已提交
2739

2740
	mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), -nr_pages);
K
KAMEZAWA Hiroyuki 已提交
2741

2742
	ClearPageCgroupUsed(pc);
2743 2744 2745 2746 2747 2748
	/*
	 * 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.
	 */
2749

2750
	unlock_page_cgroup(pc);
K
KAMEZAWA Hiroyuki 已提交
2751 2752 2753 2754
	/*
	 * even after unlock, we have mem->res.usage here and this memcg
	 * will never be freed.
	 */
2755
	memcg_check_events(mem, page);
K
KAMEZAWA Hiroyuki 已提交
2756 2757 2758 2759 2760
	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))
2761
		mem_cgroup_do_uncharge(mem, nr_pages, ctype);
2762

2763
	return mem;
K
KAMEZAWA Hiroyuki 已提交
2764 2765 2766

unlock_out:
	unlock_page_cgroup(pc);
2767
	return NULL;
2768 2769
}

2770 2771
void mem_cgroup_uncharge_page(struct page *page)
{
2772 2773 2774 2775 2776
	/* early check. */
	if (page_mapped(page))
		return;
	if (page->mapping && !PageAnon(page))
		return;
2777 2778 2779 2780 2781 2782
	__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));
2783
	VM_BUG_ON(page->mapping);
2784 2785 2786
	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
}

2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800
/*
 * 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;
2801 2802
		current->memcg_batch.nr_pages = 0;
		current->memcg_batch.memsw_nr_pages = 0;
2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822
	}
}

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.
	 */
2823 2824 2825 2826 2827 2828
	if (batch->nr_pages)
		res_counter_uncharge(&batch->memcg->res,
				     batch->nr_pages * PAGE_SIZE);
	if (batch->memsw_nr_pages)
		res_counter_uncharge(&batch->memcg->memsw,
				     batch->memsw_nr_pages * PAGE_SIZE);
2829
	memcg_oom_recover(batch->memcg);
2830 2831 2832 2833
	/* forget this pointer (for sanity check) */
	batch->memcg = NULL;
}

2834
#ifdef CONFIG_SWAP
2835
/*
2836
 * called after __delete_from_swap_cache() and drop "page" account.
2837 2838
 * memcg information is recorded to swap_cgroup of "ent"
 */
K
KAMEZAWA Hiroyuki 已提交
2839 2840
void
mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
2841 2842
{
	struct mem_cgroup *memcg;
K
KAMEZAWA Hiroyuki 已提交
2843 2844 2845 2846 2847 2848
	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);
2849

K
KAMEZAWA Hiroyuki 已提交
2850 2851 2852 2853 2854
	/*
	 * record memcg information,  if swapout && memcg != NULL,
	 * mem_cgroup_get() was called in uncharge().
	 */
	if (do_swap_account && swapout && memcg)
2855
		swap_cgroup_record(ent, css_id(&memcg->css));
2856
}
2857
#endif
2858 2859 2860 2861 2862 2863 2864

#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
2865
{
2866
	struct mem_cgroup *memcg;
2867
	unsigned short id;
2868 2869 2870 2871

	if (!do_swap_account)
		return;

2872 2873 2874
	id = swap_cgroup_record(ent, 0);
	rcu_read_lock();
	memcg = mem_cgroup_lookup(id);
2875
	if (memcg) {
2876 2877 2878 2879
		/*
		 * We uncharge this because swap is freed.
		 * This memcg can be obsolete one. We avoid calling css_tryget
		 */
2880
		if (!mem_cgroup_is_root(memcg))
2881
			res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2882
		mem_cgroup_swap_statistics(memcg, false);
2883 2884
		mem_cgroup_put(memcg);
	}
2885
	rcu_read_unlock();
K
KAMEZAWA Hiroyuki 已提交
2886
}
2887 2888 2889 2890 2891 2892

/**
 * 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
2893
 * @need_fixup: whether we should fixup res_counters and refcounts.
2894 2895 2896 2897 2898 2899 2900 2901 2902 2903
 *
 * 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,
2904
		struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2905 2906 2907 2908 2909 2910 2911 2912
{
	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);
2913
		mem_cgroup_swap_statistics(to, true);
2914
		/*
2915 2916 2917 2918 2919 2920
		 * 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.
2921 2922
		 */
		mem_cgroup_get(to);
2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933
		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);
		}
2934 2935 2936 2937 2938 2939
		return 0;
	}
	return -EINVAL;
}
#else
static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
2940
		struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2941 2942 2943
{
	return -EINVAL;
}
2944
#endif
K
KAMEZAWA Hiroyuki 已提交
2945

2946
/*
2947 2948
 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
 * page belongs to.
2949
 */
2950
int mem_cgroup_prepare_migration(struct page *page,
2951
	struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask)
2952
{
2953
	struct mem_cgroup *mem = NULL;
2954
	struct page_cgroup *pc;
2955
	enum charge_type ctype;
2956
	int ret = 0;
2957

2958 2959
	*ptr = NULL;

A
Andrea Arcangeli 已提交
2960
	VM_BUG_ON(PageTransHuge(page));
2961
	if (mem_cgroup_disabled())
2962 2963
		return 0;

2964 2965 2966
	pc = lookup_page_cgroup(page);
	lock_page_cgroup(pc);
	if (PageCgroupUsed(pc)) {
2967 2968
		mem = pc->mem_cgroup;
		css_get(&mem->css);
2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999
		/*
		 * 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);
3000
	}
3001
	unlock_page_cgroup(pc);
3002 3003 3004 3005 3006 3007
	/*
	 * If the page is not charged at this point,
	 * we return here.
	 */
	if (!mem)
		return 0;
3008

A
Andrea Arcangeli 已提交
3009
	*ptr = mem;
3010
	ret = __mem_cgroup_try_charge(NULL, gfp_mask, 1, ptr, false);
3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022
	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;
3023
	}
3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036
	/*
	 * 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;
3037
	__mem_cgroup_commit_charge(mem, page, 1, pc, ctype);
3038
	return ret;
3039
}
3040

3041
/* remove redundant charge if migration failed*/
3042
void mem_cgroup_end_migration(struct mem_cgroup *mem,
3043
	struct page *oldpage, struct page *newpage, bool migration_ok)
3044
{
3045
	struct page *used, *unused;
3046 3047 3048 3049
	struct page_cgroup *pc;

	if (!mem)
		return;
3050
	/* blocks rmdir() */
3051
	cgroup_exclude_rmdir(&mem->css);
3052
	if (!migration_ok) {
3053 3054
		used = oldpage;
		unused = newpage;
3055
	} else {
3056
		used = newpage;
3057 3058
		unused = oldpage;
	}
3059
	/*
3060 3061 3062
	 * 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.
3063
	 */
3064 3065 3066 3067
	pc = lookup_page_cgroup(oldpage);
	lock_page_cgroup(pc);
	ClearPageCgroupMigration(pc);
	unlock_page_cgroup(pc);
3068

3069 3070
	__mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);

3071
	/*
3072 3073 3074 3075 3076 3077
	 * 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)
3078
	 */
3079 3080
	if (PageAnon(used))
		mem_cgroup_uncharge_page(used);
3081
	/*
3082 3083
	 * At migration, we may charge account against cgroup which has no
	 * tasks.
3084 3085 3086 3087
	 * 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);
3088
}
3089

3090
/*
3091 3092 3093 3094 3095 3096
 * 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.
3097
 */
3098
int mem_cgroup_shmem_charge_fallback(struct page *page,
3099 3100
			    struct mm_struct *mm,
			    gfp_t gfp_mask)
3101
{
3102
	struct mem_cgroup *mem;
3103
	int ret;
3104

3105
	if (mem_cgroup_disabled())
3106
		return 0;
3107

3108 3109 3110
	ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
	if (!ret)
		mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
3111

3112
	return ret;
3113 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
#ifdef CONFIG_DEBUG_VM
static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
{
	struct page_cgroup *pc;

	pc = lookup_page_cgroup(page);
	if (likely(pc) && PageCgroupUsed(pc))
		return pc;
	return NULL;
}

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

	return lookup_page_cgroup_used(page) != NULL;
}

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

	pc = lookup_page_cgroup_used(page);
	if (pc) {
		int ret = -1;
		char *path;

		printk(KERN_ALERT "pc:%p pc->flags:%lx pc->mem_cgroup:%p",
		       pc, pc->flags, pc->mem_cgroup);

		path = kmalloc(PATH_MAX, GFP_KERNEL);
		if (path) {
			rcu_read_lock();
			ret = cgroup_path(pc->mem_cgroup->css.cgroup,
							path, PATH_MAX);
			rcu_read_unlock();
		}

		printk(KERN_CONT "(%s)\n",
				(ret < 0) ? "cannot get the path" : path);
		kfree(path);
	}
}
#endif

3161 3162
static DEFINE_MUTEX(set_limit_mutex);

3163
static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
3164
				unsigned long long val)
3165
{
3166
	int retry_count;
3167
	u64 memswlimit, memlimit;
3168
	int ret = 0;
3169 3170
	int children = mem_cgroup_count_children(memcg);
	u64 curusage, oldusage;
3171
	int enlarge;
3172 3173 3174 3175 3176 3177 3178 3179 3180

	/*
	 * 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);
3181

3182
	enlarge = 0;
3183
	while (retry_count) {
3184 3185 3186 3187
		if (signal_pending(current)) {
			ret = -EINTR;
			break;
		}
3188 3189 3190 3191 3192 3193 3194 3195 3196 3197
		/*
		 * 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);
3198 3199
			break;
		}
3200 3201 3202 3203 3204

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

3205
		ret = res_counter_set_limit(&memcg->res, val);
3206 3207 3208 3209 3210 3211
		if (!ret) {
			if (memswlimit == val)
				memcg->memsw_is_minimum = true;
			else
				memcg->memsw_is_minimum = false;
		}
3212 3213 3214 3215 3216
		mutex_unlock(&set_limit_mutex);

		if (!ret)
			break;

3217
		mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3218 3219
						MEM_CGROUP_RECLAIM_SHRINK,
						NULL);
3220 3221 3222 3223 3224 3225
		curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
		/* Usage is reduced ? */
  		if (curusage >= oldusage)
			retry_count--;
		else
			oldusage = curusage;
3226
	}
3227 3228
	if (!ret && enlarge)
		memcg_oom_recover(memcg);
3229

3230 3231 3232
	return ret;
}

L
Li Zefan 已提交
3233 3234
static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
					unsigned long long val)
3235
{
3236
	int retry_count;
3237
	u64 memlimit, memswlimit, oldusage, curusage;
3238 3239
	int children = mem_cgroup_count_children(memcg);
	int ret = -EBUSY;
3240
	int enlarge = 0;
3241

3242 3243 3244
	/* see mem_cgroup_resize_res_limit */
 	retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
	oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261
	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;
		}
3262 3263 3264
		memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
		if (memswlimit < val)
			enlarge = 1;
3265
		ret = res_counter_set_limit(&memcg->memsw, val);
3266 3267 3268 3269 3270 3271
		if (!ret) {
			if (memlimit == val)
				memcg->memsw_is_minimum = true;
			else
				memcg->memsw_is_minimum = false;
		}
3272 3273 3274 3275 3276
		mutex_unlock(&set_limit_mutex);

		if (!ret)
			break;

3277
		mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3278
						MEM_CGROUP_RECLAIM_NOSWAP |
3279 3280
						MEM_CGROUP_RECLAIM_SHRINK,
						NULL);
3281
		curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3282
		/* Usage is reduced ? */
3283
		if (curusage >= oldusage)
3284
			retry_count--;
3285 3286
		else
			oldusage = curusage;
3287
	}
3288 3289
	if (!ret && enlarge)
		memcg_oom_recover(memcg);
3290 3291 3292
	return ret;
}

3293
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3294 3295
					    gfp_t gfp_mask,
					    unsigned long *total_scanned)
3296 3297 3298 3299 3300 3301
{
	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;
3302
	unsigned long long excess;
3303
	unsigned long nr_scanned;
3304 3305 3306 3307

	if (order > 0)
		return 0;

3308
	mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321
	/*
	 * 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;

3322
		nr_scanned = 0;
3323 3324
		reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone,
						gfp_mask,
3325 3326
						MEM_CGROUP_RECLAIM_SOFT,
						&nr_scanned);
3327
		nr_reclaimed += reclaimed;
3328
		*total_scanned += nr_scanned;
3329 3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 3349 3350
		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);
3351
				if (next_mz == mz)
3352
					css_put(&next_mz->mem->css);
3353
				else /* next_mz == NULL or other memcg */
3354 3355 3356 3357
					break;
			} while (1);
		}
		__mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
3358
		excess = res_counter_soft_limit_excess(&mz->mem->res);
3359 3360 3361 3362 3363 3364 3365 3366
		/*
		 * 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.
		 */
3367 3368
		/* If excess == 0, no tree ops */
		__mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess);
3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386
		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;
}

3387 3388 3389 3390
/*
 * This routine traverse page_cgroup in given list and drop them all.
 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
 */
3391
static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
K
KAMEZAWA Hiroyuki 已提交
3392
				int node, int zid, enum lru_list lru)
3393
{
K
KAMEZAWA Hiroyuki 已提交
3394 3395
	struct zone *zone;
	struct mem_cgroup_per_zone *mz;
3396
	struct page_cgroup *pc, *busy;
K
KAMEZAWA Hiroyuki 已提交
3397
	unsigned long flags, loop;
3398
	struct list_head *list;
3399
	int ret = 0;
3400

K
KAMEZAWA Hiroyuki 已提交
3401 3402
	zone = &NODE_DATA(node)->node_zones[zid];
	mz = mem_cgroup_zoneinfo(mem, node, zid);
3403
	list = &mz->lists[lru];
3404

3405 3406 3407 3408 3409
	loop = MEM_CGROUP_ZSTAT(mz, lru);
	/* give some margin against EBUSY etc...*/
	loop += 256;
	busy = NULL;
	while (loop--) {
3410 3411
		struct page *page;

3412
		ret = 0;
K
KAMEZAWA Hiroyuki 已提交
3413
		spin_lock_irqsave(&zone->lru_lock, flags);
3414
		if (list_empty(list)) {
K
KAMEZAWA Hiroyuki 已提交
3415
			spin_unlock_irqrestore(&zone->lru_lock, flags);
3416
			break;
3417 3418 3419 3420
		}
		pc = list_entry(list->prev, struct page_cgroup, lru);
		if (busy == pc) {
			list_move(&pc->lru, list);
3421
			busy = NULL;
K
KAMEZAWA Hiroyuki 已提交
3422
			spin_unlock_irqrestore(&zone->lru_lock, flags);
3423 3424
			continue;
		}
K
KAMEZAWA Hiroyuki 已提交
3425
		spin_unlock_irqrestore(&zone->lru_lock, flags);
3426

3427
		page = lookup_cgroup_page(pc);
3428 3429

		ret = mem_cgroup_move_parent(page, pc, mem, GFP_KERNEL);
3430
		if (ret == -ENOMEM)
3431
			break;
3432 3433 3434 3435 3436 3437 3438

		if (ret == -EBUSY || ret == -EINVAL) {
			/* found lock contention or "pc" is obsolete. */
			busy = pc;
			cond_resched();
		} else
			busy = NULL;
3439
	}
K
KAMEZAWA Hiroyuki 已提交
3440

3441 3442 3443
	if (!ret && !list_empty(list))
		return -EBUSY;
	return ret;
3444 3445 3446 3447 3448 3449
}

/*
 * make mem_cgroup's charge to be 0 if there is no task.
 * This enables deleting this mem_cgroup.
 */
3450
static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
3451
{
3452 3453 3454
	int ret;
	int node, zid, shrink;
	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3455
	struct cgroup *cgrp = mem->css.cgroup;
3456

3457
	css_get(&mem->css);
3458 3459

	shrink = 0;
3460 3461 3462
	/* should free all ? */
	if (free_all)
		goto try_to_free;
3463
move_account:
3464
	do {
3465
		ret = -EBUSY;
3466 3467 3468 3469
		if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
			goto out;
		ret = -EINTR;
		if (signal_pending(current))
3470
			goto out;
3471 3472
		/* This is for making all *used* pages to be on LRU. */
		lru_add_drain_all();
3473
		drain_all_stock_sync();
3474
		ret = 0;
3475
		mem_cgroup_start_move(mem);
3476
		for_each_node_state(node, N_HIGH_MEMORY) {
3477
			for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
3478
				enum lru_list l;
3479 3480
				for_each_lru(l) {
					ret = mem_cgroup_force_empty_list(mem,
K
KAMEZAWA Hiroyuki 已提交
3481
							node, zid, l);
3482 3483 3484
					if (ret)
						break;
				}
3485
			}
3486 3487 3488
			if (ret)
				break;
		}
3489
		mem_cgroup_end_move(mem);
3490
		memcg_oom_recover(mem);
3491 3492 3493
		/* it seems parent cgroup doesn't have enough mem */
		if (ret == -ENOMEM)
			goto try_to_free;
3494
		cond_resched();
3495 3496
	/* "ret" should also be checked to ensure all lists are empty. */
	} while (mem->res.usage > 0 || ret);
3497 3498 3499
out:
	css_put(&mem->css);
	return ret;
3500 3501

try_to_free:
3502 3503
	/* returns EBUSY if there is a task or if we come here twice. */
	if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
3504 3505 3506
		ret = -EBUSY;
		goto out;
	}
3507 3508
	/* we call try-to-free pages for make this cgroup empty */
	lru_add_drain_all();
3509 3510 3511 3512
	/* try to free all pages in this cgroup */
	shrink = 1;
	while (nr_retries && mem->res.usage > 0) {
		int progress;
3513 3514 3515 3516 3517

		if (signal_pending(current)) {
			ret = -EINTR;
			goto out;
		}
K
KOSAKI Motohiro 已提交
3518 3519
		progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
						false, get_swappiness(mem));
3520
		if (!progress) {
3521
			nr_retries--;
3522
			/* maybe some writeback is necessary */
3523
			congestion_wait(BLK_RW_ASYNC, HZ/10);
3524
		}
3525 3526

	}
K
KAMEZAWA Hiroyuki 已提交
3527
	lru_add_drain();
3528
	/* try move_account...there may be some *locked* pages. */
3529
	goto move_account;
3530 3531
}

3532 3533 3534 3535 3536 3537
int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
{
	return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
}


3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555
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();
	/*
3556
	 * If parent's use_hierarchy is set, we can't make any modifications
3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575
	 * 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;
}

3576

3577 3578
static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *mem,
					       enum mem_cgroup_stat_index idx)
3579
{
K
KAMEZAWA Hiroyuki 已提交
3580
	struct mem_cgroup *iter;
3581
	long val = 0;
3582

3583
	/* Per-cpu values can be negative, use a signed accumulator */
K
KAMEZAWA Hiroyuki 已提交
3584 3585 3586 3587 3588 3589
	for_each_mem_cgroup_tree(iter, mem)
		val += mem_cgroup_read_stat(iter, idx);

	if (val < 0) /* race ? */
		val = 0;
	return val;
3590 3591
}

3592 3593
static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap)
{
K
KAMEZAWA Hiroyuki 已提交
3594
	u64 val;
3595 3596 3597 3598 3599 3600 3601 3602

	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);
	}

3603 3604
	val = mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_CACHE);
	val += mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_RSS);
3605

K
KAMEZAWA Hiroyuki 已提交
3606
	if (swap)
3607
		val += mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
3608 3609 3610 3611

	return val << PAGE_SHIFT;
}

3612
static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
B
Balbir Singh 已提交
3613
{
3614
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3615
	u64 val;
3616 3617 3618 3619 3620 3621
	int type, name;

	type = MEMFILE_TYPE(cft->private);
	name = MEMFILE_ATTR(cft->private);
	switch (type) {
	case _MEM:
3622 3623 3624
		if (name == RES_USAGE)
			val = mem_cgroup_usage(mem, false);
		else
3625
			val = res_counter_read_u64(&mem->res, name);
3626 3627
		break;
	case _MEMSWAP:
3628 3629 3630
		if (name == RES_USAGE)
			val = mem_cgroup_usage(mem, true);
		else
3631
			val = res_counter_read_u64(&mem->memsw, name);
3632 3633 3634 3635 3636 3637
		break;
	default:
		BUG();
		break;
	}
	return val;
B
Balbir Singh 已提交
3638
}
3639 3640 3641 3642
/*
 * The user of this function is...
 * RES_LIMIT.
 */
3643 3644
static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
			    const char *buffer)
B
Balbir Singh 已提交
3645
{
3646
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3647
	int type, name;
3648 3649 3650
	unsigned long long val;
	int ret;

3651 3652 3653
	type = MEMFILE_TYPE(cft->private);
	name = MEMFILE_ATTR(cft->private);
	switch (name) {
3654
	case RES_LIMIT:
3655 3656 3657 3658
		if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
			ret = -EINVAL;
			break;
		}
3659 3660
		/* This function does all necessary parse...reuse it */
		ret = res_counter_memparse_write_strategy(buffer, &val);
3661 3662 3663
		if (ret)
			break;
		if (type == _MEM)
3664
			ret = mem_cgroup_resize_limit(memcg, val);
3665 3666
		else
			ret = mem_cgroup_resize_memsw_limit(memcg, val);
3667
		break;
3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681
	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;
3682 3683 3684 3685 3686
	default:
		ret = -EINVAL; /* should be BUG() ? */
		break;
	}
	return ret;
B
Balbir Singh 已提交
3687 3688
}

3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716
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;
}

3717
static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
3718 3719
{
	struct mem_cgroup *mem;
3720
	int type, name;
3721 3722

	mem = mem_cgroup_from_cont(cont);
3723 3724 3725
	type = MEMFILE_TYPE(event);
	name = MEMFILE_ATTR(event);
	switch (name) {
3726
	case RES_MAX_USAGE:
3727 3728 3729 3730
		if (type == _MEM)
			res_counter_reset_max(&mem->res);
		else
			res_counter_reset_max(&mem->memsw);
3731 3732
		break;
	case RES_FAILCNT:
3733 3734 3735 3736
		if (type == _MEM)
			res_counter_reset_failcnt(&mem->res);
		else
			res_counter_reset_failcnt(&mem->memsw);
3737 3738
		break;
	}
3739

3740
	return 0;
3741 3742
}

3743 3744 3745 3746 3747 3748
static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
					struct cftype *cft)
{
	return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
}

3749
#ifdef CONFIG_MMU
3750 3751 3752 3753 3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767
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;
}
3768 3769 3770 3771 3772 3773 3774
#else
static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
					struct cftype *cft, u64 val)
{
	return -ENOSYS;
}
#endif
3775

K
KAMEZAWA Hiroyuki 已提交
3776 3777 3778 3779 3780

/* For read statistics */
enum {
	MCS_CACHE,
	MCS_RSS,
3781
	MCS_FILE_MAPPED,
K
KAMEZAWA Hiroyuki 已提交
3782 3783
	MCS_PGPGIN,
	MCS_PGPGOUT,
3784
	MCS_SWAP,
K
KAMEZAWA Hiroyuki 已提交
3785 3786 3787 3788 3789 3790 3791 3792 3793 3794
	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];
3795 3796
};

K
KAMEZAWA Hiroyuki 已提交
3797 3798 3799 3800 3801 3802
struct {
	char *local_name;
	char *total_name;
} memcg_stat_strings[NR_MCS_STAT] = {
	{"cache", "total_cache"},
	{"rss", "total_rss"},
3803
	{"mapped_file", "total_mapped_file"},
K
KAMEZAWA Hiroyuki 已提交
3804 3805
	{"pgpgin", "total_pgpgin"},
	{"pgpgout", "total_pgpgout"},
3806
	{"swap", "total_swap"},
K
KAMEZAWA Hiroyuki 已提交
3807 3808 3809 3810 3811 3812 3813 3814
	{"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
3815 3816
static void
mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
K
KAMEZAWA Hiroyuki 已提交
3817 3818 3819 3820
{
	s64 val;

	/* per cpu stat */
3821
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
K
KAMEZAWA Hiroyuki 已提交
3822
	s->stat[MCS_CACHE] += val * PAGE_SIZE;
3823
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
K
KAMEZAWA Hiroyuki 已提交
3824
	s->stat[MCS_RSS] += val * PAGE_SIZE;
3825
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED);
3826
	s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
3827
	val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGPGIN);
K
KAMEZAWA Hiroyuki 已提交
3828
	s->stat[MCS_PGPGIN] += val;
3829
	val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGPGOUT);
K
KAMEZAWA Hiroyuki 已提交
3830
	s->stat[MCS_PGPGOUT] += val;
3831
	if (do_swap_account) {
3832
		val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
3833 3834
		s->stat[MCS_SWAP] += val * PAGE_SIZE;
	}
K
KAMEZAWA Hiroyuki 已提交
3835 3836 3837 3838 3839 3840 3841 3842 3843 3844 3845 3846 3847 3848 3849 3850 3851

	/* 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
3852 3853 3854 3855
	struct mem_cgroup *iter;

	for_each_mem_cgroup_tree(iter, mem)
		mem_cgroup_get_local_stat(iter, s);
K
KAMEZAWA Hiroyuki 已提交
3856 3857
}

3858 3859
static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
				 struct cgroup_map_cb *cb)
3860 3861
{
	struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
K
KAMEZAWA Hiroyuki 已提交
3862
	struct mcs_total_stat mystat;
3863 3864
	int i;

K
KAMEZAWA Hiroyuki 已提交
3865 3866
	memset(&mystat, 0, sizeof(mystat));
	mem_cgroup_get_local_stat(mem_cont, &mystat);
3867

3868 3869 3870
	for (i = 0; i < NR_MCS_STAT; i++) {
		if (i == MCS_SWAP && !do_swap_account)
			continue;
K
KAMEZAWA Hiroyuki 已提交
3871
		cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
3872
	}
L
Lee Schermerhorn 已提交
3873

K
KAMEZAWA Hiroyuki 已提交
3874
	/* Hierarchical information */
3875 3876 3877 3878 3879 3880 3881
	{
		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
3882

K
KAMEZAWA Hiroyuki 已提交
3883 3884
	memset(&mystat, 0, sizeof(mystat));
	mem_cgroup_get_total_stat(mem_cont, &mystat);
3885 3886 3887
	for (i = 0; i < NR_MCS_STAT; i++) {
		if (i == MCS_SWAP && !do_swap_account)
			continue;
K
KAMEZAWA Hiroyuki 已提交
3888
		cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
3889
	}
K
KAMEZAWA Hiroyuki 已提交
3890

K
KOSAKI Motohiro 已提交
3891
#ifdef CONFIG_DEBUG_VM
3892
	cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
K
KOSAKI Motohiro 已提交
3893 3894 3895 3896 3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914 3915 3916 3917 3918 3919

	{
		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

3920 3921 3922
	return 0;
}

K
KOSAKI Motohiro 已提交
3923 3924 3925 3926 3927 3928 3929 3930 3931 3932 3933 3934
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;
3935

K
KOSAKI Motohiro 已提交
3936 3937 3938 3939 3940 3941 3942
	if (val > 100)
		return -EINVAL;

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

	parent = mem_cgroup_from_cont(cgrp->parent);
3943 3944 3945

	cgroup_lock();

K
KOSAKI Motohiro 已提交
3946 3947
	/* If under hierarchy, only empty-root can set this value */
	if ((parent->use_hierarchy) ||
3948 3949
	    (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
		cgroup_unlock();
K
KOSAKI Motohiro 已提交
3950
		return -EINVAL;
3951
	}
K
KOSAKI Motohiro 已提交
3952 3953 3954

	memcg->swappiness = val;

3955 3956
	cgroup_unlock();

K
KOSAKI Motohiro 已提交
3957 3958 3959
	return 0;
}

3960 3961 3962 3963 3964 3965 3966 3967
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)
3968
		t = rcu_dereference(memcg->thresholds.primary);
3969
	else
3970
		t = rcu_dereference(memcg->memsw_thresholds.primary);
3971 3972 3973 3974 3975 3976 3977 3978 3979 3980 3981

	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().
	 */
3982
	i = t->current_threshold;
3983 3984 3985 3986 3987 3988 3989 3990 3991 3992 3993 3994 3995 3996 3997 3998 3999 4000 4001 4002 4003 4004 4005

	/*
	 * 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 */
4006
	t->current_threshold = i - 1;
4007 4008 4009 4010 4011 4012
unlock:
	rcu_read_unlock();
}

static void mem_cgroup_threshold(struct mem_cgroup *memcg)
{
4013 4014 4015 4016 4017 4018 4019
	while (memcg) {
		__mem_cgroup_threshold(memcg, false);
		if (do_swap_account)
			__mem_cgroup_threshold(memcg, true);

		memcg = parent_mem_cgroup(memcg);
	}
4020 4021 4022 4023 4024 4025 4026 4027 4028 4029
}

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
4030
static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem)
K
KAMEZAWA Hiroyuki 已提交
4031 4032 4033 4034 4035 4036 4037 4038 4039 4040
{
	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
4041 4042 4043 4044
	struct mem_cgroup *iter;

	for_each_mem_cgroup_tree(iter, mem)
		mem_cgroup_oom_notify_cb(iter);
K
KAMEZAWA Hiroyuki 已提交
4045 4046 4047 4048
}

static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
	struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
4049 4050
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4051 4052
	struct mem_cgroup_thresholds *thresholds;
	struct mem_cgroup_threshold_ary *new;
4053 4054
	int type = MEMFILE_TYPE(cft->private);
	u64 threshold, usage;
4055
	int i, size, ret;
4056 4057 4058 4059 4060 4061

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

	mutex_lock(&memcg->thresholds_lock);
4062

4063
	if (type == _MEM)
4064
		thresholds = &memcg->thresholds;
4065
	else if (type == _MEMSWAP)
4066
		thresholds = &memcg->memsw_thresholds;
4067 4068 4069 4070 4071 4072
	else
		BUG();

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

	/* Check if a threshold crossed before adding a new one */
4073
	if (thresholds->primary)
4074 4075
		__mem_cgroup_threshold(memcg, type == _MEMSWAP);

4076
	size = thresholds->primary ? thresholds->primary->size + 1 : 1;
4077 4078

	/* Allocate memory for new array of thresholds */
4079
	new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
4080
			GFP_KERNEL);
4081
	if (!new) {
4082 4083 4084
		ret = -ENOMEM;
		goto unlock;
	}
4085
	new->size = size;
4086 4087

	/* Copy thresholds (if any) to new array */
4088 4089
	if (thresholds->primary) {
		memcpy(new->entries, thresholds->primary->entries, (size - 1) *
4090
				sizeof(struct mem_cgroup_threshold));
4091 4092
	}

4093
	/* Add new threshold */
4094 4095
	new->entries[size - 1].eventfd = eventfd;
	new->entries[size - 1].threshold = threshold;
4096 4097

	/* Sort thresholds. Registering of new threshold isn't time-critical */
4098
	sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
4099 4100 4101
			compare_thresholds, NULL);

	/* Find current threshold */
4102
	new->current_threshold = -1;
4103
	for (i = 0; i < size; i++) {
4104
		if (new->entries[i].threshold < usage) {
4105
			/*
4106 4107
			 * new->current_threshold will not be used until
			 * rcu_assign_pointer(), so it's safe to increment
4108 4109
			 * it here.
			 */
4110
			++new->current_threshold;
4111 4112 4113
		}
	}

4114 4115 4116 4117 4118
	/* Free old spare buffer and save old primary buffer as spare */
	kfree(thresholds->spare);
	thresholds->spare = thresholds->primary;

	rcu_assign_pointer(thresholds->primary, new);
4119

4120
	/* To be sure that nobody uses thresholds */
4121 4122 4123 4124 4125 4126 4127 4128
	synchronize_rcu();

unlock:
	mutex_unlock(&memcg->thresholds_lock);

	return ret;
}

4129
static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
K
KAMEZAWA Hiroyuki 已提交
4130
	struct cftype *cft, struct eventfd_ctx *eventfd)
4131 4132
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4133 4134
	struct mem_cgroup_thresholds *thresholds;
	struct mem_cgroup_threshold_ary *new;
4135 4136
	int type = MEMFILE_TYPE(cft->private);
	u64 usage;
4137
	int i, j, size;
4138 4139 4140

	mutex_lock(&memcg->thresholds_lock);
	if (type == _MEM)
4141
		thresholds = &memcg->thresholds;
4142
	else if (type == _MEMSWAP)
4143
		thresholds = &memcg->memsw_thresholds;
4144 4145 4146 4147 4148 4149 4150 4151 4152 4153 4154 4155 4156 4157 4158
	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 */
4159 4160 4161
	size = 0;
	for (i = 0; i < thresholds->primary->size; i++) {
		if (thresholds->primary->entries[i].eventfd != eventfd)
4162 4163 4164
			size++;
	}

4165
	new = thresholds->spare;
4166

4167 4168
	/* Set thresholds array to NULL if we don't have thresholds */
	if (!size) {
4169 4170
		kfree(new);
		new = NULL;
4171
		goto swap_buffers;
4172 4173
	}

4174
	new->size = size;
4175 4176

	/* Copy thresholds and find current threshold */
4177 4178 4179
	new->current_threshold = -1;
	for (i = 0, j = 0; i < thresholds->primary->size; i++) {
		if (thresholds->primary->entries[i].eventfd == eventfd)
4180 4181
			continue;

4182 4183
		new->entries[j] = thresholds->primary->entries[i];
		if (new->entries[j].threshold < usage) {
4184
			/*
4185
			 * new->current_threshold will not be used
4186 4187 4188
			 * until rcu_assign_pointer(), so it's safe to increment
			 * it here.
			 */
4189
			++new->current_threshold;
4190 4191 4192 4193
		}
		j++;
	}

4194
swap_buffers:
4195 4196 4197
	/* Swap primary and spare array */
	thresholds->spare = thresholds->primary;
	rcu_assign_pointer(thresholds->primary, new);
4198

4199
	/* To be sure that nobody uses thresholds */
4200 4201 4202 4203
	synchronize_rcu();

	mutex_unlock(&memcg->thresholds_lock);
}
4204

K
KAMEZAWA Hiroyuki 已提交
4205 4206 4207 4208 4209 4210 4211 4212 4213 4214 4215 4216 4217 4218 4219 4220 4221 4222 4223 4224 4225 4226 4227 4228 4229
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;
}

4230
static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
K
KAMEZAWA Hiroyuki 已提交
4231 4232 4233 4234 4235 4236 4237 4238 4239 4240 4241 4242 4243 4244 4245 4246 4247 4248 4249 4250
	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);
}

4251 4252 4253 4254 4255 4256 4257 4258 4259 4260 4261 4262 4263 4264 4265 4266 4267 4268 4269 4270 4271 4272 4273 4274 4275 4276 4277 4278 4279 4280 4281 4282 4283 4284
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;
4285 4286
	if (!val)
		memcg_oom_recover(mem);
4287 4288 4289 4290
	cgroup_unlock();
	return 0;
}

B
Balbir Singh 已提交
4291 4292
static struct cftype mem_cgroup_files[] = {
	{
4293
		.name = "usage_in_bytes",
4294
		.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4295
		.read_u64 = mem_cgroup_read,
K
KAMEZAWA Hiroyuki 已提交
4296 4297
		.register_event = mem_cgroup_usage_register_event,
		.unregister_event = mem_cgroup_usage_unregister_event,
B
Balbir Singh 已提交
4298
	},
4299 4300
	{
		.name = "max_usage_in_bytes",
4301
		.private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4302
		.trigger = mem_cgroup_reset,
4303 4304
		.read_u64 = mem_cgroup_read,
	},
B
Balbir Singh 已提交
4305
	{
4306
		.name = "limit_in_bytes",
4307
		.private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4308
		.write_string = mem_cgroup_write,
4309
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
4310
	},
4311 4312 4313 4314 4315 4316
	{
		.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
4317 4318
	{
		.name = "failcnt",
4319
		.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4320
		.trigger = mem_cgroup_reset,
4321
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
4322
	},
4323 4324
	{
		.name = "stat",
4325
		.read_map = mem_control_stat_show,
4326
	},
4327 4328 4329 4330
	{
		.name = "force_empty",
		.trigger = mem_cgroup_force_empty_write,
	},
4331 4332 4333 4334 4335
	{
		.name = "use_hierarchy",
		.write_u64 = mem_cgroup_hierarchy_write,
		.read_u64 = mem_cgroup_hierarchy_read,
	},
K
KOSAKI Motohiro 已提交
4336 4337 4338 4339 4340
	{
		.name = "swappiness",
		.read_u64 = mem_cgroup_swappiness_read,
		.write_u64 = mem_cgroup_swappiness_write,
	},
4341 4342 4343 4344 4345
	{
		.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
4346 4347
	{
		.name = "oom_control",
4348 4349
		.read_map = mem_cgroup_oom_control_read,
		.write_u64 = mem_cgroup_oom_control_write,
K
KAMEZAWA Hiroyuki 已提交
4350 4351 4352 4353
		.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
4354 4355
};

4356 4357 4358 4359 4360 4361
#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
4362 4363
		.register_event = mem_cgroup_usage_register_event,
		.unregister_event = mem_cgroup_usage_unregister_event,
4364 4365 4366 4367 4368 4369 4370 4371 4372 4373 4374 4375 4376 4377 4378 4379 4380 4381 4382 4383 4384 4385 4386 4387 4388 4389 4390 4391 4392 4393 4394 4395 4396 4397 4398
	},
	{
		.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

4399 4400 4401
static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
	struct mem_cgroup_per_node *pn;
4402
	struct mem_cgroup_per_zone *mz;
4403
	enum lru_list l;
4404
	int zone, tmp = node;
4405 4406 4407 4408 4409 4410 4411 4412
	/*
	 * 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.
	 */
4413 4414
	if (!node_state(node, N_NORMAL_MEMORY))
		tmp = -1;
4415
	pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4416 4417
	if (!pn)
		return 1;
4418

4419
	mem->info.nodeinfo[node] = pn;
4420 4421
	for (zone = 0; zone < MAX_NR_ZONES; zone++) {
		mz = &pn->zoneinfo[zone];
4422 4423
		for_each_lru(l)
			INIT_LIST_HEAD(&mz->lists[l]);
4424
		mz->usage_in_excess = 0;
4425 4426
		mz->on_tree = false;
		mz->mem = mem;
4427
	}
4428 4429 4430
	return 0;
}

4431 4432 4433 4434 4435
static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
	kfree(mem->info.nodeinfo[node]);
}

4436 4437 4438
static struct mem_cgroup *mem_cgroup_alloc(void)
{
	struct mem_cgroup *mem;
4439
	int size = sizeof(struct mem_cgroup);
4440

4441
	/* Can be very big if MAX_NUMNODES is very big */
4442
	if (size < PAGE_SIZE)
4443
		mem = kzalloc(size, GFP_KERNEL);
4444
	else
4445
		mem = vzalloc(size);
4446

4447 4448 4449
	if (!mem)
		return NULL;

4450
	mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4451 4452
	if (!mem->stat)
		goto out_free;
4453
	spin_lock_init(&mem->pcp_counter_lock);
4454
	return mem;
4455 4456 4457 4458 4459 4460 4461

out_free:
	if (size < PAGE_SIZE)
		kfree(mem);
	else
		vfree(mem);
	return NULL;
4462 4463
}

4464 4465 4466 4467 4468 4469 4470 4471 4472 4473 4474
/*
 * 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.
 */

4475
static void __mem_cgroup_free(struct mem_cgroup *mem)
4476
{
K
KAMEZAWA Hiroyuki 已提交
4477 4478
	int node;

4479
	mem_cgroup_remove_from_trees(mem);
K
KAMEZAWA Hiroyuki 已提交
4480 4481
	free_css_id(&mem_cgroup_subsys, &mem->css);

K
KAMEZAWA Hiroyuki 已提交
4482 4483 4484
	for_each_node_state(node, N_POSSIBLE)
		free_mem_cgroup_per_zone_info(mem, node);

4485 4486
	free_percpu(mem->stat);
	if (sizeof(struct mem_cgroup) < PAGE_SIZE)
4487 4488 4489 4490 4491
		kfree(mem);
	else
		vfree(mem);
}

4492 4493 4494 4495 4496
static void mem_cgroup_get(struct mem_cgroup *mem)
{
	atomic_inc(&mem->refcnt);
}

4497
static void __mem_cgroup_put(struct mem_cgroup *mem, int count)
4498
{
4499
	if (atomic_sub_and_test(count, &mem->refcnt)) {
4500
		struct mem_cgroup *parent = parent_mem_cgroup(mem);
4501
		__mem_cgroup_free(mem);
4502 4503 4504
		if (parent)
			mem_cgroup_put(parent);
	}
4505 4506
}

4507 4508 4509 4510 4511
static void mem_cgroup_put(struct mem_cgroup *mem)
{
	__mem_cgroup_put(mem, 1);
}

4512 4513 4514 4515 4516 4517 4518 4519 4520
/*
 * 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);
}
4521

4522 4523 4524
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
static void __init enable_swap_cgroup(void)
{
4525
	if (!mem_cgroup_disabled() && really_do_swap_account)
4526 4527 4528 4529 4530 4531 4532 4533
		do_swap_account = 1;
}
#else
static void __init enable_swap_cgroup(void)
{
}
#endif

4534 4535 4536 4537 4538 4539 4540 4541 4542 4543 4544 4545 4546 4547 4548 4549 4550 4551 4552 4553 4554 4555 4556 4557 4558
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
4559
static struct cgroup_subsys_state * __ref
B
Balbir Singh 已提交
4560 4561
mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
{
4562
	struct mem_cgroup *mem, *parent;
K
KAMEZAWA Hiroyuki 已提交
4563
	long error = -ENOMEM;
4564
	int node;
B
Balbir Singh 已提交
4565

4566 4567
	mem = mem_cgroup_alloc();
	if (!mem)
K
KAMEZAWA Hiroyuki 已提交
4568
		return ERR_PTR(error);
4569

4570 4571 4572
	for_each_node_state(node, N_POSSIBLE)
		if (alloc_mem_cgroup_per_zone_info(mem, node))
			goto free_out;
4573

4574
	/* root ? */
4575
	if (cont->parent == NULL) {
4576
		int cpu;
4577
		enable_swap_cgroup();
4578
		parent = NULL;
4579
		root_mem_cgroup = mem;
4580 4581
		if (mem_cgroup_soft_limit_tree_init())
			goto free_out;
4582 4583 4584 4585 4586
		for_each_possible_cpu(cpu) {
			struct memcg_stock_pcp *stock =
						&per_cpu(memcg_stock, cpu);
			INIT_WORK(&stock->work, drain_local_stock);
		}
4587
		hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
4588
	} else {
4589
		parent = mem_cgroup_from_cont(cont->parent);
4590
		mem->use_hierarchy = parent->use_hierarchy;
4591
		mem->oom_kill_disable = parent->oom_kill_disable;
4592
	}
4593

4594 4595 4596
	if (parent && parent->use_hierarchy) {
		res_counter_init(&mem->res, &parent->res);
		res_counter_init(&mem->memsw, &parent->memsw);
4597 4598 4599 4600 4601 4602 4603
		/*
		 * 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);
4604 4605 4606 4607
	} else {
		res_counter_init(&mem->res, NULL);
		res_counter_init(&mem->memsw, NULL);
	}
K
KAMEZAWA Hiroyuki 已提交
4608
	mem->last_scanned_child = 0;
K
KAMEZAWA Hiroyuki 已提交
4609
	INIT_LIST_HEAD(&mem->oom_notify);
4610

K
KOSAKI Motohiro 已提交
4611 4612
	if (parent)
		mem->swappiness = get_swappiness(parent);
4613
	atomic_set(&mem->refcnt, 1);
4614
	mem->move_charge_at_immigrate = 0;
4615
	mutex_init(&mem->thresholds_lock);
B
Balbir Singh 已提交
4616
	return &mem->css;
4617
free_out:
4618
	__mem_cgroup_free(mem);
4619
	root_mem_cgroup = NULL;
K
KAMEZAWA Hiroyuki 已提交
4620
	return ERR_PTR(error);
B
Balbir Singh 已提交
4621 4622
}

4623
static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
4624 4625 4626
					struct cgroup *cont)
{
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4627 4628

	return mem_cgroup_force_empty(mem, false);
4629 4630
}

B
Balbir Singh 已提交
4631 4632 4633
static void mem_cgroup_destroy(struct cgroup_subsys *ss,
				struct cgroup *cont)
{
4634 4635 4636
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);

	mem_cgroup_put(mem);
B
Balbir Singh 已提交
4637 4638 4639 4640 4641
}

static int mem_cgroup_populate(struct cgroup_subsys *ss,
				struct cgroup *cont)
{
4642 4643 4644 4645 4646 4647 4648 4649
	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
4650 4651
}

4652
#ifdef CONFIG_MMU
4653
/* Handlers for move charge at task migration. */
4654 4655
#define PRECHARGE_COUNT_AT_ONCE	256
static int mem_cgroup_do_precharge(unsigned long count)
4656
{
4657 4658
	int ret = 0;
	int batch_count = PRECHARGE_COUNT_AT_ONCE;
4659 4660
	struct mem_cgroup *mem = mc.to;

4661 4662 4663 4664 4665 4666 4667 4668 4669 4670 4671 4672 4673 4674 4675 4676 4677 4678 4679 4680 4681 4682 4683 4684 4685 4686 4687 4688 4689 4690 4691 4692 4693 4694 4695
	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();
		}
4696
		ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, 1, &mem, false);
4697 4698 4699 4700 4701
		if (ret || !mem)
			/* mem_cgroup_clear_mc() will do uncharge later */
			return -ENOMEM;
		mc.precharge++;
	}
4702 4703 4704 4705 4706 4707 4708 4709
	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
4710
 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4711 4712 4713 4714 4715 4716
 *
 * 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).
4717 4718 4719
 *   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.
4720 4721 4722 4723 4724
 *
 * Called with pte lock held.
 */
union mc_target {
	struct page	*page;
4725
	swp_entry_t	ent;
4726 4727 4728 4729 4730
};

enum mc_target_type {
	MC_TARGET_NONE,	/* not used */
	MC_TARGET_PAGE,
4731
	MC_TARGET_SWAP,
4732 4733
};

D
Daisuke Nishimura 已提交
4734 4735
static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
						unsigned long addr, pte_t ptent)
4736
{
D
Daisuke Nishimura 已提交
4737
	struct page *page = vm_normal_page(vma, addr, ptent);
4738

D
Daisuke Nishimura 已提交
4739 4740 4741 4742 4743 4744
	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;
4745 4746
	} else if (!move_file())
		/* we ignore mapcount for file pages */
D
Daisuke Nishimura 已提交
4747 4748 4749 4750 4751 4752 4753 4754 4755 4756 4757 4758 4759 4760 4761 4762 4763 4764
		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 */
4765 4766
		if (page)
			put_page(page);
D
Daisuke Nishimura 已提交
4767
		return NULL;
4768
	}
D
Daisuke Nishimura 已提交
4769 4770 4771 4772 4773 4774
	if (do_swap_account)
		entry->val = ent.val;

	return page;
}

4775 4776 4777 4778 4779 4780 4781 4782 4783 4784 4785 4786 4787 4788 4789 4790 4791 4792 4793 4794 4795 4796 4797 4798 4799 4800 4801 4802 4803 4804 4805 4806 4807
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
4808 4809 4810 4811 4812 4813 4814 4815 4816 4817 4818 4819
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);
4820 4821
	else if (pte_none(ptent) || pte_file(ptent))
		page = mc_handle_file_pte(vma, addr, ptent, &ent);
D
Daisuke Nishimura 已提交
4822 4823 4824

	if (!page && !ent.val)
		return 0;
4825 4826 4827 4828 4829 4830 4831 4832 4833 4834 4835 4836 4837 4838 4839
	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
4840 4841
	/* There is a swap entry and a page doesn't exist or isn't charged */
	if (ent.val && !ret &&
4842 4843 4844 4845
			css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
		ret = MC_TARGET_SWAP;
		if (target)
			target->ent = ent;
4846 4847 4848 4849 4850 4851 4852 4853 4854 4855 4856 4857
	}
	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;

4858 4859
	split_huge_page_pmd(walk->mm, pmd);

4860 4861 4862 4863 4864 4865 4866
	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();

4867 4868 4869
	return 0;
}

4870 4871 4872 4873 4874
static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
{
	unsigned long precharge;
	struct vm_area_struct *vma;

4875
	down_read(&mm->mmap_sem);
4876 4877 4878 4879 4880 4881 4882 4883 4884 4885 4886
	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);
	}
4887
	up_read(&mm->mmap_sem);
4888 4889 4890 4891 4892 4893 4894 4895 4896

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

	return precharge;
}

static int mem_cgroup_precharge_mc(struct mm_struct *mm)
{
4897 4898 4899 4900 4901
	unsigned long precharge = mem_cgroup_count_precharge(mm);

	VM_BUG_ON(mc.moving_task);
	mc.moving_task = current;
	return mem_cgroup_do_precharge(precharge);
4902 4903
}

4904 4905
/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
static void __mem_cgroup_clear_mc(void)
4906
{
4907 4908 4909
	struct mem_cgroup *from = mc.from;
	struct mem_cgroup *to = mc.to;

4910
	/* we must uncharge all the leftover precharges from mc.to */
4911 4912 4913 4914 4915 4916 4917 4918 4919 4920 4921
	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;
4922
	}
4923 4924 4925 4926 4927 4928 4929 4930 4931 4932 4933 4934 4935 4936 4937 4938 4939 4940 4941
	/* 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;
	}
4942 4943 4944 4945 4946 4947 4948 4949 4950 4951 4952 4953 4954 4955 4956
	memcg_oom_recover(from);
	memcg_oom_recover(to);
	wake_up_all(&mc.waitq);
}

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

	/*
	 * we must clear moving_task before waking up waiters at the end of
	 * task migration.
	 */
	mc.moving_task = NULL;
	__mem_cgroup_clear_mc();
4957
	spin_lock(&mc.lock);
4958 4959
	mc.from = NULL;
	mc.to = NULL;
4960
	spin_unlock(&mc.lock);
4961
	mem_cgroup_end_move(from);
4962 4963
}

4964 4965
static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
				struct cgroup *cgroup,
4966
				struct task_struct *p)
4967 4968 4969 4970 4971 4972 4973 4974 4975 4976 4977 4978 4979 4980
{
	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 */
4981 4982 4983 4984
		if (mm->owner == p) {
			VM_BUG_ON(mc.from);
			VM_BUG_ON(mc.to);
			VM_BUG_ON(mc.precharge);
4985
			VM_BUG_ON(mc.moved_charge);
4986
			VM_BUG_ON(mc.moved_swap);
4987
			mem_cgroup_start_move(from);
4988
			spin_lock(&mc.lock);
4989 4990
			mc.from = from;
			mc.to = mem;
4991
			spin_unlock(&mc.lock);
4992
			/* We set mc.moving_task later */
4993 4994 4995 4996

			ret = mem_cgroup_precharge_mc(mm);
			if (ret)
				mem_cgroup_clear_mc();
4997 4998
		}
		mmput(mm);
4999 5000 5001 5002 5003 5004
	}
	return ret;
}

static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
				struct cgroup *cgroup,
5005
				struct task_struct *p)
5006
{
5007
	mem_cgroup_clear_mc();
5008 5009
}

5010 5011 5012
static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
				unsigned long addr, unsigned long end,
				struct mm_walk *walk)
5013
{
5014 5015 5016 5017 5018
	int ret = 0;
	struct vm_area_struct *vma = walk->private;
	pte_t *pte;
	spinlock_t *ptl;

5019
	split_huge_page_pmd(walk->mm, pmd);
5020 5021 5022 5023 5024 5025 5026 5027
retry:
	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
	for (; addr != end; addr += PAGE_SIZE) {
		pte_t ptent = *(pte++);
		union mc_target target;
		int type;
		struct page *page;
		struct page_cgroup *pc;
5028
		swp_entry_t ent;
5029 5030 5031 5032 5033 5034 5035 5036 5037 5038 5039

		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);
5040 5041
			if (!mem_cgroup_move_account(page, 1, pc,
						     mc.from, mc.to, false)) {
5042
				mc.precharge--;
5043 5044
				/* we uncharge from mc.from later. */
				mc.moved_charge++;
5045 5046 5047 5048 5049
			}
			putback_lru_page(page);
put:			/* is_target_pte_for_mc() gets the page */
			put_page(page);
			break;
5050 5051
		case MC_TARGET_SWAP:
			ent = target.ent;
5052 5053
			if (!mem_cgroup_move_swap_account(ent,
						mc.from, mc.to, false)) {
5054
				mc.precharge--;
5055 5056 5057
				/* we fixup refcnts and charges later. */
				mc.moved_swap++;
			}
5058
			break;
5059 5060 5061 5062 5063 5064 5065 5066 5067 5068 5069 5070 5071 5072
		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.
		 */
5073
		ret = mem_cgroup_do_precharge(1);
5074 5075 5076 5077 5078 5079 5080 5081 5082 5083 5084 5085
		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();
5086 5087 5088 5089 5090 5091 5092 5093 5094 5095 5096 5097 5098
retry:
	if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
		/*
		 * Someone who are holding the mmap_sem might be waiting in
		 * waitq. So we cancel all extra charges, wake up all waiters,
		 * and retry. Because we cancel precharges, we might not be able
		 * to move enough charges, but moving charge is a best-effort
		 * feature anyway, so it wouldn't be a big problem.
		 */
		__mem_cgroup_clear_mc();
		cond_resched();
		goto retry;
	}
5099 5100 5101 5102 5103 5104 5105 5106 5107 5108 5109 5110 5111 5112 5113 5114 5115 5116
	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;
	}
5117
	up_read(&mm->mmap_sem);
5118 5119
}

B
Balbir Singh 已提交
5120 5121 5122
static void mem_cgroup_move_task(struct cgroup_subsys *ss,
				struct cgroup *cont,
				struct cgroup *old_cont,
5123
				struct task_struct *p)
B
Balbir Singh 已提交
5124
{
5125 5126 5127
	struct mm_struct *mm;

	if (!mc.to)
5128 5129 5130
		/* no need to move charge */
		return;

5131 5132 5133 5134 5135
	mm = get_task_mm(p);
	if (mm) {
		mem_cgroup_move_charge(mm);
		mmput(mm);
	}
5136
	mem_cgroup_clear_mc();
B
Balbir Singh 已提交
5137
}
5138 5139 5140
#else	/* !CONFIG_MMU */
static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
				struct cgroup *cgroup,
5141
				struct task_struct *p)
5142 5143 5144 5145 5146
{
	return 0;
}
static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
				struct cgroup *cgroup,
5147
				struct task_struct *p)
5148 5149 5150 5151 5152
{
}
static void mem_cgroup_move_task(struct cgroup_subsys *ss,
				struct cgroup *cont,
				struct cgroup *old_cont,
5153
				struct task_struct *p)
5154 5155 5156
{
}
#endif
B
Balbir Singh 已提交
5157

B
Balbir Singh 已提交
5158 5159 5160 5161
struct cgroup_subsys mem_cgroup_subsys = {
	.name = "memory",
	.subsys_id = mem_cgroup_subsys_id,
	.create = mem_cgroup_create,
5162
	.pre_destroy = mem_cgroup_pre_destroy,
B
Balbir Singh 已提交
5163 5164
	.destroy = mem_cgroup_destroy,
	.populate = mem_cgroup_populate,
5165 5166
	.can_attach = mem_cgroup_can_attach,
	.cancel_attach = mem_cgroup_cancel_attach,
B
Balbir Singh 已提交
5167
	.attach = mem_cgroup_move_task,
5168
	.early_init = 0,
K
KAMEZAWA Hiroyuki 已提交
5169
	.use_id = 1,
B
Balbir Singh 已提交
5170
};
5171 5172

#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
5173 5174 5175
static int __init enable_swap_account(char *s)
{
	/* consider enabled if no parameter or 1 is given */
5176
	if (!strcmp(s, "1"))
5177
		really_do_swap_account = 1;
5178
	else if (!strcmp(s, "0"))
5179 5180 5181
		really_do_swap_account = 0;
	return 1;
}
5182
__setup("swapaccount=", enable_swap_account);
5183 5184

#endif