memcontrol.c 133.4 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 1436
						gfp_t gfp_mask,
						unsigned long reclaim_options)
1437
{
K
KAMEZAWA Hiroyuki 已提交
1438 1439 1440
	struct mem_cgroup *victim;
	int ret, total = 0;
	int loop = 0;
1441 1442
	bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
	bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
1443
	bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
1444 1445 1446
	unsigned long excess;

	excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT;
K
KAMEZAWA Hiroyuki 已提交
1447

1448 1449 1450 1451
	/* If memsw_is_minimum==1, swap-out is of-no-use. */
	if (root_mem->memsw_is_minimum)
		noswap = true;

1452
	while (1) {
K
KAMEZAWA Hiroyuki 已提交
1453
		victim = mem_cgroup_select_victim(root_mem);
1454
		if (victim == root_mem) {
K
KAMEZAWA Hiroyuki 已提交
1455
			loop++;
1456 1457
			if (loop >= 1)
				drain_all_stock_async();
1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468
			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
1469
				 * We want to do more targeted reclaim.
1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480
				 * 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;
				}
			}
		}
1481
		if (!mem_cgroup_local_usage(victim)) {
K
KAMEZAWA Hiroyuki 已提交
1482 1483
			/* this cgroup's local usage == 0 */
			css_put(&victim->css);
1484 1485
			continue;
		}
K
KAMEZAWA Hiroyuki 已提交
1486
		/* we use swappiness of local cgroup */
1487 1488
		if (check_soft)
			ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
1489
				noswap, get_swappiness(victim), zone);
1490 1491 1492
		else
			ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
						noswap, get_swappiness(victim));
K
KAMEZAWA Hiroyuki 已提交
1493
		css_put(&victim->css);
1494 1495 1496 1497 1498 1499 1500
		/*
		 * 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
1501
		total += ret;
1502
		if (check_soft) {
1503
			if (!res_counter_soft_limit_excess(&root_mem->res))
1504
				return total;
1505
		} else if (mem_cgroup_margin(root_mem))
K
KAMEZAWA Hiroyuki 已提交
1506
			return 1 + total;
1507
	}
K
KAMEZAWA Hiroyuki 已提交
1508
	return total;
1509 1510
}

K
KAMEZAWA Hiroyuki 已提交
1511 1512 1513 1514 1515 1516
/*
 * 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
1517 1518
	int x, lock_count = 0;
	struct mem_cgroup *iter;
1519

K
KAMEZAWA Hiroyuki 已提交
1520 1521 1522 1523
	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
1524 1525 1526 1527

	if (lock_count == 1)
		return true;
	return false;
1528
}
1529

K
KAMEZAWA Hiroyuki 已提交
1530
static int mem_cgroup_oom_unlock(struct mem_cgroup *mem)
1531
{
K
KAMEZAWA Hiroyuki 已提交
1532 1533
	struct mem_cgroup *iter;

K
KAMEZAWA Hiroyuki 已提交
1534 1535 1536 1537 1538
	/*
	 * 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
1539 1540
	for_each_mem_cgroup_tree(iter, mem)
		atomic_add_unless(&iter->oom_lock, -1, 0);
1541 1542 1543
	return 0;
}

K
KAMEZAWA Hiroyuki 已提交
1544 1545 1546 1547

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

K
KAMEZAWA Hiroyuki 已提交
1548 1549 1550 1551 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
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);
}

1584 1585
static void memcg_oom_recover(struct mem_cgroup *mem)
{
1586
	if (mem && atomic_read(&mem->oom_lock))
1587 1588 1589
		memcg_wakeup_oom(mem);
}

K
KAMEZAWA Hiroyuki 已提交
1590 1591 1592 1593
/*
 * 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)
1594
{
K
KAMEZAWA Hiroyuki 已提交
1595
	struct oom_wait_info owait;
1596
	bool locked, need_to_kill;
K
KAMEZAWA Hiroyuki 已提交
1597

K
KAMEZAWA Hiroyuki 已提交
1598 1599 1600 1601 1602
	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);
1603
	need_to_kill = true;
K
KAMEZAWA Hiroyuki 已提交
1604 1605 1606 1607 1608 1609 1610 1611
	/* 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.
	 */
1612 1613 1614 1615
	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
1616
		mem_cgroup_oom_notify(mem);
K
KAMEZAWA Hiroyuki 已提交
1617 1618
	mutex_unlock(&memcg_oom_mutex);

1619 1620
	if (need_to_kill) {
		finish_wait(&memcg_oom_waitq, &owait.wait);
K
KAMEZAWA Hiroyuki 已提交
1621
		mem_cgroup_out_of_memory(mem, mask);
1622
	} else {
K
KAMEZAWA Hiroyuki 已提交
1623
		schedule();
K
KAMEZAWA Hiroyuki 已提交
1624
		finish_wait(&memcg_oom_waitq, &owait.wait);
K
KAMEZAWA Hiroyuki 已提交
1625 1626 1627
	}
	mutex_lock(&memcg_oom_mutex);
	mem_cgroup_oom_unlock(mem);
K
KAMEZAWA Hiroyuki 已提交
1628
	memcg_wakeup_oom(mem);
K
KAMEZAWA Hiroyuki 已提交
1629 1630 1631 1632 1633 1634 1635
	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;
1636 1637
}

1638 1639 1640
/*
 * Currently used to update mapped file statistics, but the routine can be
 * generalized to update other statistics as well.
1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659
 *
 * 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.
1660
 */
1661

1662 1663
void mem_cgroup_update_page_stat(struct page *page,
				 enum mem_cgroup_page_stat_item idx, int val)
1664 1665
{
	struct mem_cgroup *mem;
1666 1667
	struct page_cgroup *pc = lookup_page_cgroup(page);
	bool need_unlock = false;
1668
	unsigned long uninitialized_var(flags);
1669 1670 1671 1672

	if (unlikely(!pc))
		return;

1673
	rcu_read_lock();
1674
	mem = pc->mem_cgroup;
1675 1676 1677
	if (unlikely(!mem || !PageCgroupUsed(pc)))
		goto out;
	/* pc->mem_cgroup is unstable ? */
1678
	if (unlikely(mem_cgroup_stealed(mem)) || PageTransHuge(page)) {
1679
		/* take a lock against to access pc->mem_cgroup */
1680
		move_lock_page_cgroup(pc, &flags);
1681 1682 1683 1684 1685
		need_unlock = true;
		mem = pc->mem_cgroup;
		if (!mem || !PageCgroupUsed(pc))
			goto out;
	}
1686 1687

	switch (idx) {
1688
	case MEMCG_NR_FILE_MAPPED:
1689 1690 1691
		if (val > 0)
			SetPageCgroupFileMapped(pc);
		else if (!page_mapped(page))
1692
			ClearPageCgroupFileMapped(pc);
1693
		idx = MEM_CGROUP_STAT_FILE_MAPPED;
1694 1695 1696
		break;
	default:
		BUG();
1697
	}
1698

1699 1700
	this_cpu_add(mem->stat->count[idx], val);

1701 1702
out:
	if (unlikely(need_unlock))
1703
		move_unlock_page_cgroup(pc, &flags);
1704 1705
	rcu_read_unlock();
	return;
1706
}
1707
EXPORT_SYMBOL(mem_cgroup_update_page_stat);
1708

1709 1710 1711 1712
/*
 * size of first charge trial. "32" comes from vmscan.c's magic value.
 * TODO: maybe necessary to use big numbers in big irons.
 */
1713
#define CHARGE_BATCH	32U
1714 1715
struct memcg_stock_pcp {
	struct mem_cgroup *cached; /* this never be root cgroup */
1716
	unsigned int nr_pages;
1717 1718 1719 1720 1721 1722
	struct work_struct work;
};
static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
static atomic_t memcg_drain_count;

/*
1723
 * Try to consume stocked charge on this cpu. If success, one page is consumed
1724 1725 1726 1727 1728 1729 1730 1731 1732 1733
 * 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);
1734 1735
	if (mem == stock->cached && stock->nr_pages)
		stock->nr_pages--;
1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748
	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;

1749 1750 1751 1752
	if (stock->nr_pages) {
		unsigned long bytes = stock->nr_pages * PAGE_SIZE;

		res_counter_uncharge(&old->res, bytes);
1753
		if (do_swap_account)
1754 1755
			res_counter_uncharge(&old->memsw, bytes);
		stock->nr_pages = 0;
1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771
	}
	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.
1772
 * This will be consumed by consume_stock() function, later.
1773
 */
1774
static void refill_stock(struct mem_cgroup *mem, unsigned int nr_pages)
1775 1776 1777 1778 1779 1780 1781
{
	struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);

	if (stock->cached != mem) { /* reset if necessary */
		drain_stock(stock);
		stock->cached = mem;
	}
1782
	stock->nr_pages += nr_pages;
1783 1784 1785 1786 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
	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);
}

1824 1825 1826 1827 1828 1829 1830 1831 1832 1833
/*
 * 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++) {
1834
		long x = per_cpu(mem->stat->count[i], cpu);
1835 1836 1837 1838

		per_cpu(mem->stat->count[i], cpu) = 0;
		mem->nocpu_base.count[i] += x;
	}
1839 1840 1841 1842 1843 1844
	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;
	}
1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855
	/* 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];
1856 1857 1858 1859
	spin_unlock(&mem->pcp_counter_lock);
}

static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
1860 1861 1862 1863 1864
					unsigned long action,
					void *hcpu)
{
	int cpu = (unsigned long)hcpu;
	struct memcg_stock_pcp *stock;
1865
	struct mem_cgroup *iter;
1866

1867 1868 1869 1870 1871 1872
	if ((action == CPU_ONLINE)) {
		for_each_mem_cgroup_all(iter)
			synchronize_mem_cgroup_on_move(iter, cpu);
		return NOTIFY_OK;
	}

1873
	if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN)
1874
		return NOTIFY_OK;
1875 1876 1877 1878

	for_each_mem_cgroup_all(iter)
		mem_cgroup_drain_pcp_counter(iter, cpu);

1879 1880 1881 1882 1883
	stock = &per_cpu(memcg_stock, cpu);
	drain_stock(stock);
	return NOTIFY_OK;
}

1884 1885 1886 1887 1888 1889 1890 1891 1892 1893

/* 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 */
};

1894 1895
static int mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask,
				unsigned int nr_pages, bool oom_check)
1896
{
1897
	unsigned long csize = nr_pages * PAGE_SIZE;
1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911
	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;

1912
		res_counter_uncharge(&mem->res, csize);
1913 1914 1915 1916
		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);
1917
	/*
1918 1919
	 * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch
	 * of regular pages (CHARGE_BATCH), or a single regular page (1).
1920 1921 1922 1923
	 *
	 * Never reclaim on behalf of optional batching, retry with a
	 * single page instead.
	 */
1924
	if (nr_pages == CHARGE_BATCH)
1925 1926 1927 1928 1929 1930
		return CHARGE_RETRY;

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

	ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
1931
					      gfp_mask, flags);
1932
	if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
1933
		return CHARGE_RETRY;
1934
	/*
1935 1936 1937 1938 1939 1940 1941
	 * 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.
1942
	 */
1943
	if (nr_pages == 1 && ret)
1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962
		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;
}

1963 1964 1965
/*
 * Unlike exported interface, "oom" parameter is added. if oom==true,
 * oom-killer can be invoked.
1966
 */
1967
static int __mem_cgroup_try_charge(struct mm_struct *mm,
A
Andrea Arcangeli 已提交
1968
				   gfp_t gfp_mask,
1969 1970 1971
				   unsigned int nr_pages,
				   struct mem_cgroup **memcg,
				   bool oom)
1972
{
1973
	unsigned int batch = max(CHARGE_BATCH, nr_pages);
1974 1975 1976
	int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
	struct mem_cgroup *mem = NULL;
	int ret;
1977

K
KAMEZAWA Hiroyuki 已提交
1978 1979 1980 1981 1982 1983 1984 1985
	/*
	 * 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;
1986

1987
	/*
1988 1989
	 * We always charge the cgroup the mm_struct belongs to.
	 * The mm_struct's mem_cgroup changes on task migration if the
1990 1991 1992
	 * 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
1993 1994 1995 1996
	if (!*memcg && !mm)
		goto bypass;
again:
	if (*memcg) { /* css should be a valid one */
1997
		mem = *memcg;
K
KAMEZAWA Hiroyuki 已提交
1998 1999 2000
		VM_BUG_ON(css_is_removed(&mem->css));
		if (mem_cgroup_is_root(mem))
			goto done;
2001
		if (nr_pages == 1 && consume_stock(mem))
K
KAMEZAWA Hiroyuki 已提交
2002
			goto done;
2003 2004
		css_get(&mem->css);
	} else {
K
KAMEZAWA Hiroyuki 已提交
2005
		struct task_struct *p;
2006

K
KAMEZAWA Hiroyuki 已提交
2007 2008 2009
		rcu_read_lock();
		p = rcu_dereference(mm->owner);
		/*
2010 2011 2012 2013 2014 2015 2016 2017
		 * 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
2018 2019
		 */
		mem = mem_cgroup_from_task(p);
2020
		if (!mem || mem_cgroup_is_root(mem)) {
K
KAMEZAWA Hiroyuki 已提交
2021 2022 2023
			rcu_read_unlock();
			goto done;
		}
2024
		if (nr_pages == 1 && consume_stock(mem)) {
K
KAMEZAWA Hiroyuki 已提交
2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042
			/*
			 * 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();
	}
2043

2044 2045
	do {
		bool oom_check;
2046

2047
		/* If killed, bypass charge */
K
KAMEZAWA Hiroyuki 已提交
2048 2049
		if (fatal_signal_pending(current)) {
			css_put(&mem->css);
2050
			goto bypass;
K
KAMEZAWA Hiroyuki 已提交
2051
		}
2052

2053 2054 2055 2056
		oom_check = false;
		if (oom && !nr_oom_retries) {
			oom_check = true;
			nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2057
		}
2058

2059
		ret = mem_cgroup_do_charge(mem, gfp_mask, batch, oom_check);
2060 2061 2062 2063
		switch (ret) {
		case CHARGE_OK:
			break;
		case CHARGE_RETRY: /* not in OOM situation but retry */
2064
			batch = nr_pages;
K
KAMEZAWA Hiroyuki 已提交
2065 2066 2067
			css_put(&mem->css);
			mem = NULL;
			goto again;
2068
		case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
K
KAMEZAWA Hiroyuki 已提交
2069
			css_put(&mem->css);
2070 2071
			goto nomem;
		case CHARGE_NOMEM: /* OOM routine works */
K
KAMEZAWA Hiroyuki 已提交
2072 2073
			if (!oom) {
				css_put(&mem->css);
K
KAMEZAWA Hiroyuki 已提交
2074
				goto nomem;
K
KAMEZAWA Hiroyuki 已提交
2075
			}
2076 2077 2078 2079
			/* If oom, we never return -ENOMEM */
			nr_oom_retries--;
			break;
		case CHARGE_OOM_DIE: /* Killed by OOM Killer */
K
KAMEZAWA Hiroyuki 已提交
2080
			css_put(&mem->css);
K
KAMEZAWA Hiroyuki 已提交
2081
			goto bypass;
2082
		}
2083 2084
	} while (ret != CHARGE_OK);

2085 2086
	if (batch > nr_pages)
		refill_stock(mem, batch - nr_pages);
K
KAMEZAWA Hiroyuki 已提交
2087
	css_put(&mem->css);
2088
done:
K
KAMEZAWA Hiroyuki 已提交
2089
	*memcg = mem;
2090 2091
	return 0;
nomem:
K
KAMEZAWA Hiroyuki 已提交
2092
	*memcg = NULL;
2093
	return -ENOMEM;
K
KAMEZAWA Hiroyuki 已提交
2094 2095 2096
bypass:
	*memcg = NULL;
	return 0;
2097
}
2098

2099 2100 2101 2102 2103
/*
 * 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().
 */
2104
static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem,
2105
				       unsigned int nr_pages)
2106 2107
{
	if (!mem_cgroup_is_root(mem)) {
2108 2109 2110
		unsigned long bytes = nr_pages * PAGE_SIZE;

		res_counter_uncharge(&mem->res, bytes);
2111
		if (do_swap_account)
2112
			res_counter_uncharge(&mem->memsw, bytes);
2113
	}
2114 2115
}

2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134
/*
 * 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);
}

2135
struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2136
{
2137
	struct mem_cgroup *mem = NULL;
2138
	struct page_cgroup *pc;
2139
	unsigned short id;
2140 2141
	swp_entry_t ent;

2142 2143 2144
	VM_BUG_ON(!PageLocked(page));

	pc = lookup_page_cgroup(page);
2145
	lock_page_cgroup(pc);
2146
	if (PageCgroupUsed(pc)) {
2147
		mem = pc->mem_cgroup;
2148 2149
		if (mem && !css_tryget(&mem->css))
			mem = NULL;
2150
	} else if (PageSwapCache(page)) {
2151
		ent.val = page_private(page);
2152 2153 2154 2155 2156 2157
		id = lookup_swap_cgroup(ent);
		rcu_read_lock();
		mem = mem_cgroup_lookup(id);
		if (mem && !css_tryget(&mem->css))
			mem = NULL;
		rcu_read_unlock();
2158
	}
2159
	unlock_page_cgroup(pc);
2160 2161 2162
	return mem;
}

2163
static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
2164
				       struct page *page,
2165
				       unsigned int nr_pages,
2166
				       struct page_cgroup *pc,
2167
				       enum charge_type ctype)
2168
{
2169 2170 2171
	lock_page_cgroup(pc);
	if (unlikely(PageCgroupUsed(pc))) {
		unlock_page_cgroup(pc);
2172
		__mem_cgroup_cancel_charge(mem, nr_pages);
2173 2174 2175 2176 2177 2178
		return;
	}
	/*
	 * we don't need page_cgroup_lock about tail pages, becase they are not
	 * accessed by any other context at this point.
	 */
2179
	pc->mem_cgroup = mem;
2180 2181 2182 2183 2184 2185 2186
	/*
	 * 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
2187
	smp_wmb();
2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200
	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;
	}
2201

2202
	mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), nr_pages);
2203
	unlock_page_cgroup(pc);
2204 2205 2206 2207 2208
	/*
	 * "charge_statistics" updated event counter. Then, check it.
	 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
	 * if they exceeds softlimit.
	 */
2209
	memcg_check_events(mem, page);
2210
}
2211

2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225
#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;

2226 2227
	if (mem_cgroup_disabled())
		return;
2228
	/*
2229
	 * We have no races with charge/uncharge but will have races with
2230 2231 2232 2233 2234 2235
	 * page state accounting.
	 */
	move_lock_page_cgroup(head_pc, &flags);

	tail_pc->mem_cgroup = head_pc->mem_cgroup;
	smp_wmb(); /* see __commit_charge() */
2236 2237 2238 2239 2240 2241 2242 2243 2244 2245
	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);
2246
		mz = page_cgroup_zoneinfo(head_pc->mem_cgroup, head);
2247 2248
		MEM_CGROUP_ZSTAT(mz, lru) -= 1;
	}
2249 2250 2251 2252 2253
	tail_pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
	move_unlock_page_cgroup(head_pc, &flags);
}
#endif

2254
/**
2255
 * mem_cgroup_move_account - move account of the page
2256
 * @page: the page
2257
 * @nr_pages: number of regular pages (>1 for huge pages)
2258 2259 2260
 * @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.
2261
 * @uncharge: whether we should call uncharge and css_put against @from.
2262 2263
 *
 * The caller must confirm following.
K
KAMEZAWA Hiroyuki 已提交
2264
 * - page is not on LRU (isolate_page() is useful.)
2265
 * - compound_lock is held when nr_pages > 1
2266
 *
2267
 * This function doesn't do "charge" nor css_get to new cgroup. It should be
L
Lucas De Marchi 已提交
2268
 * done by a caller(__mem_cgroup_try_charge would be useful). If @uncharge is
2269 2270
 * true, this function does "uncharge" from old cgroup, but it doesn't if
 * @uncharge is false, so a caller should do "uncharge".
2271
 */
2272 2273 2274 2275 2276 2277
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)
2278
{
2279 2280
	unsigned long flags;
	int ret;
2281

2282
	VM_BUG_ON(from == to);
2283
	VM_BUG_ON(PageLRU(page));
2284 2285 2286 2287 2288 2289 2290
	/*
	 * 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;
2291
	if (nr_pages > 1 && !PageTransHuge(page))
2292 2293 2294 2295 2296 2297 2298 2299 2300
		goto out;

	lock_page_cgroup(pc);

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

	move_lock_page_cgroup(pc, &flags);
2301

2302
	if (PageCgroupFileMapped(pc)) {
2303 2304 2305 2306 2307
		/* 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();
2308
	}
2309
	mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages);
2310 2311
	if (uncharge)
		/* This is not "cancel", but cancel_charge does all we need. */
2312
		__mem_cgroup_cancel_charge(from, nr_pages);
2313

2314
	/* caller should have done css_get */
K
KAMEZAWA Hiroyuki 已提交
2315
	pc->mem_cgroup = to;
2316
	mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages);
2317 2318 2319
	/*
	 * We charges against "to" which may not have any tasks. Then, "to"
	 * can be under rmdir(). But in current implementation, caller of
2320
	 * this function is just force_empty() and move charge, so it's
L
Lucas De Marchi 已提交
2321
	 * guaranteed that "to" is never removed. So, we don't check rmdir
2322
	 * status here.
2323
	 */
2324 2325 2326
	move_unlock_page_cgroup(pc, &flags);
	ret = 0;
unlock:
2327
	unlock_page_cgroup(pc);
2328 2329 2330
	/*
	 * check events
	 */
2331 2332
	memcg_check_events(to, page);
	memcg_check_events(from, page);
2333
out:
2334 2335 2336 2337 2338 2339 2340
	return ret;
}

/*
 * move charges to its parent.
 */

2341 2342
static int mem_cgroup_move_parent(struct page *page,
				  struct page_cgroup *pc,
2343 2344 2345 2346 2347 2348
				  struct mem_cgroup *child,
				  gfp_t gfp_mask)
{
	struct cgroup *cg = child->css.cgroup;
	struct cgroup *pcg = cg->parent;
	struct mem_cgroup *parent;
2349
	unsigned int nr_pages;
2350
	unsigned long uninitialized_var(flags);
2351 2352 2353 2354 2355 2356
	int ret;

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

2357 2358 2359 2360 2361
	ret = -EBUSY;
	if (!get_page_unless_zero(page))
		goto out;
	if (isolate_lru_page(page))
		goto put;
2362

2363
	nr_pages = hpage_nr_pages(page);
K
KAMEZAWA Hiroyuki 已提交
2364

2365
	parent = mem_cgroup_from_cont(pcg);
2366
	ret = __mem_cgroup_try_charge(NULL, gfp_mask, nr_pages, &parent, false);
2367
	if (ret || !parent)
2368
		goto put_back;
2369

2370
	if (nr_pages > 1)
2371 2372
		flags = compound_lock_irqsave(page);

2373
	ret = mem_cgroup_move_account(page, nr_pages, pc, child, parent, true);
2374
	if (ret)
2375
		__mem_cgroup_cancel_charge(parent, nr_pages);
2376

2377
	if (nr_pages > 1)
2378
		compound_unlock_irqrestore(page, flags);
2379
put_back:
K
KAMEZAWA Hiroyuki 已提交
2380
	putback_lru_page(page);
2381
put:
2382
	put_page(page);
2383
out:
2384 2385 2386
	return ret;
}

2387 2388 2389 2390 2391 2392 2393
/*
 * 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,
2394
				gfp_t gfp_mask, enum charge_type ctype)
2395
{
2396
	struct mem_cgroup *mem = NULL;
2397
	unsigned int nr_pages = 1;
2398
	struct page_cgroup *pc;
2399
	bool oom = true;
2400
	int ret;
A
Andrea Arcangeli 已提交
2401

A
Andrea Arcangeli 已提交
2402
	if (PageTransHuge(page)) {
2403
		nr_pages <<= compound_order(page);
A
Andrea Arcangeli 已提交
2404
		VM_BUG_ON(!PageTransHuge(page));
2405 2406 2407 2408 2409
		/*
		 * 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
2410
	}
2411 2412

	pc = lookup_page_cgroup(page);
2413
	BUG_ON(!pc); /* XXX: remove this and move pc lookup into commit */
2414

2415
	ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &mem, oom);
2416
	if (ret || !mem)
2417 2418
		return ret;

2419
	__mem_cgroup_commit_charge(mem, page, nr_pages, pc, ctype);
2420 2421 2422
	return 0;
}

2423 2424
int mem_cgroup_newpage_charge(struct page *page,
			      struct mm_struct *mm, gfp_t gfp_mask)
2425
{
2426
	if (mem_cgroup_disabled())
2427
		return 0;
2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438
	/*
	 * 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;
2439
	return mem_cgroup_charge_common(page, mm, gfp_mask,
2440
				MEM_CGROUP_CHARGE_TYPE_MAPPED);
2441 2442
}

D
Daisuke Nishimura 已提交
2443 2444 2445 2446
static void
__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
					enum charge_type ctype);

2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462
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;
}

2463 2464
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
				gfp_t gfp_mask)
2465
{
2466
	struct mem_cgroup *mem = NULL;
2467 2468
	int ret;

2469
	if (mem_cgroup_disabled())
2470
		return 0;
2471 2472
	if (PageCompound(page))
		return 0;
2473 2474 2475 2476 2477 2478 2479 2480
	/*
	 * 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.)
2481 2482
	 * And when the page is SwapCache, it should take swap information
	 * into account. This is under lock_page() now.
2483 2484 2485 2486
	 */
	if (!(gfp_mask & __GFP_WAIT)) {
		struct page_cgroup *pc;

2487 2488 2489 2490 2491 2492
		pc = lookup_page_cgroup(page);
		if (!pc)
			return 0;
		lock_page_cgroup(pc);
		if (PageCgroupUsed(pc)) {
			unlock_page_cgroup(pc);
2493 2494
			return 0;
		}
2495
		unlock_page_cgroup(pc);
2496 2497
	}

2498
	if (unlikely(!mm))
2499
		mm = &init_mm;
2500

2501 2502 2503 2504
	if (page_is_file_cache(page)) {
		ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, &mem, true);
		if (ret || !mem)
			return ret;
2505

2506 2507 2508 2509 2510 2511 2512 2513 2514
		/*
		 * 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
2515 2516 2517 2518 2519 2520 2521 2522
	/* 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,
2523
					MEM_CGROUP_CHARGE_TYPE_SHMEM);
2524 2525

	return ret;
2526 2527
}

2528 2529 2530
/*
 * While swap-in, try_charge -> commit or cancel, the page is locked.
 * And when try_charge() successfully returns, one refcnt to memcg without
2531
 * struct page_cgroup is acquired. This refcnt will be consumed by
2532 2533
 * "commit()" or removed by "cancel()"
 */
2534 2535 2536 2537 2538
int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
				 struct page *page,
				 gfp_t mask, struct mem_cgroup **ptr)
{
	struct mem_cgroup *mem;
2539
	int ret;
2540

2541 2542
	*ptr = NULL;

2543
	if (mem_cgroup_disabled())
2544 2545 2546 2547 2548 2549
		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
2550 2551 2552
	 * 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.
2553 2554
	 */
	if (!PageSwapCache(page))
H
Hugh Dickins 已提交
2555
		goto charge_cur_mm;
2556
	mem = try_get_mem_cgroup_from_page(page);
2557 2558
	if (!mem)
		goto charge_cur_mm;
2559
	*ptr = mem;
2560
	ret = __mem_cgroup_try_charge(NULL, mask, 1, ptr, true);
2561 2562
	css_put(&mem->css);
	return ret;
2563 2564 2565
charge_cur_mm:
	if (unlikely(!mm))
		mm = &init_mm;
2566
	return __mem_cgroup_try_charge(mm, mask, 1, ptr, true);
2567 2568
}

D
Daisuke Nishimura 已提交
2569 2570 2571
static void
__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
					enum charge_type ctype)
2572
{
2573
	if (mem_cgroup_disabled())
2574 2575 2576
		return;
	if (!ptr)
		return;
2577
	cgroup_exclude_rmdir(&ptr->css);
2578 2579

	__mem_cgroup_commit_charge_lrucare(page, ptr, ctype);
2580 2581 2582
	/*
	 * Now swap is on-memory. This means this page may be
	 * counted both as mem and swap....double count.
2583 2584 2585
	 * 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.
2586
	 */
2587
	if (do_swap_account && PageSwapCache(page)) {
2588
		swp_entry_t ent = {.val = page_private(page)};
2589
		unsigned short id;
2590
		struct mem_cgroup *memcg;
2591 2592 2593 2594

		id = swap_cgroup_record(ent, 0);
		rcu_read_lock();
		memcg = mem_cgroup_lookup(id);
2595
		if (memcg) {
2596 2597 2598 2599
			/*
			 * This recorded memcg can be obsolete one. So, avoid
			 * calling css_tryget
			 */
2600
			if (!mem_cgroup_is_root(memcg))
2601
				res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2602
			mem_cgroup_swap_statistics(memcg, false);
2603 2604
			mem_cgroup_put(memcg);
		}
2605
		rcu_read_unlock();
2606
	}
2607 2608 2609 2610 2611 2612
	/*
	 * 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);
2613 2614
}

D
Daisuke Nishimura 已提交
2615 2616 2617 2618 2619 2620
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);
}

2621 2622
void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
{
2623
	if (mem_cgroup_disabled())
2624 2625 2626
		return;
	if (!mem)
		return;
2627
	__mem_cgroup_cancel_charge(mem, 1);
2628 2629
}

2630 2631 2632
static void mem_cgroup_do_uncharge(struct mem_cgroup *mem,
				   unsigned int nr_pages,
				   const enum charge_type ctype)
2633 2634 2635
{
	struct memcg_batch_info *batch = NULL;
	bool uncharge_memsw = true;
2636

2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648
	/* 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;
2649 2650
	/*
	 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
L
Lucas De Marchi 已提交
2651
	 * In those cases, all pages freed continuously can be expected to be in
2652 2653 2654 2655 2656 2657 2658 2659
	 * 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;

2660
	if (nr_pages > 1)
A
Andrea Arcangeli 已提交
2661 2662
		goto direct_uncharge;

2663 2664 2665 2666 2667 2668 2669 2670
	/*
	 * 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 */
2671
	batch->nr_pages++;
2672
	if (uncharge_memsw)
2673
		batch->memsw_nr_pages++;
2674 2675
	return;
direct_uncharge:
2676
	res_counter_uncharge(&mem->res, nr_pages * PAGE_SIZE);
2677
	if (uncharge_memsw)
2678
		res_counter_uncharge(&mem->memsw, nr_pages * PAGE_SIZE);
2679 2680
	if (unlikely(batch->memcg != mem))
		memcg_oom_recover(mem);
2681 2682
	return;
}
2683

2684
/*
2685
 * uncharge if !page_mapped(page)
2686
 */
2687
static struct mem_cgroup *
2688
__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
2689
{
2690
	struct mem_cgroup *mem = NULL;
2691 2692
	unsigned int nr_pages = 1;
	struct page_cgroup *pc;
2693

2694
	if (mem_cgroup_disabled())
2695
		return NULL;
2696

K
KAMEZAWA Hiroyuki 已提交
2697
	if (PageSwapCache(page))
2698
		return NULL;
K
KAMEZAWA Hiroyuki 已提交
2699

A
Andrea Arcangeli 已提交
2700
	if (PageTransHuge(page)) {
2701
		nr_pages <<= compound_order(page);
A
Andrea Arcangeli 已提交
2702 2703
		VM_BUG_ON(!PageTransHuge(page));
	}
2704
	/*
2705
	 * Check if our page_cgroup is valid
2706
	 */
2707 2708
	pc = lookup_page_cgroup(page);
	if (unlikely(!pc || !PageCgroupUsed(pc)))
2709
		return NULL;
2710

2711
	lock_page_cgroup(pc);
K
KAMEZAWA Hiroyuki 已提交
2712

2713 2714
	mem = pc->mem_cgroup;

K
KAMEZAWA Hiroyuki 已提交
2715 2716 2717 2718 2719
	if (!PageCgroupUsed(pc))
		goto unlock_out;

	switch (ctype) {
	case MEM_CGROUP_CHARGE_TYPE_MAPPED:
K
KAMEZAWA Hiroyuki 已提交
2720
	case MEM_CGROUP_CHARGE_TYPE_DROP:
2721 2722
		/* See mem_cgroup_prepare_migration() */
		if (page_mapped(page) || PageCgroupMigration(pc))
K
KAMEZAWA Hiroyuki 已提交
2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733
			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;
2734
	}
K
KAMEZAWA Hiroyuki 已提交
2735

2736
	mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), -nr_pages);
K
KAMEZAWA Hiroyuki 已提交
2737

2738
	ClearPageCgroupUsed(pc);
2739 2740 2741 2742 2743 2744
	/*
	 * 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.
	 */
2745

2746
	unlock_page_cgroup(pc);
K
KAMEZAWA Hiroyuki 已提交
2747 2748 2749 2750
	/*
	 * even after unlock, we have mem->res.usage here and this memcg
	 * will never be freed.
	 */
2751
	memcg_check_events(mem, page);
K
KAMEZAWA Hiroyuki 已提交
2752 2753 2754 2755 2756
	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))
2757
		mem_cgroup_do_uncharge(mem, nr_pages, ctype);
2758

2759
	return mem;
K
KAMEZAWA Hiroyuki 已提交
2760 2761 2762

unlock_out:
	unlock_page_cgroup(pc);
2763
	return NULL;
2764 2765
}

2766 2767
void mem_cgroup_uncharge_page(struct page *page)
{
2768 2769 2770 2771 2772
	/* early check. */
	if (page_mapped(page))
		return;
	if (page->mapping && !PageAnon(page))
		return;
2773 2774 2775 2776 2777 2778
	__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));
2779
	VM_BUG_ON(page->mapping);
2780 2781 2782
	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
}

2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796
/*
 * 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;
2797 2798
		current->memcg_batch.nr_pages = 0;
		current->memcg_batch.memsw_nr_pages = 0;
2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818
	}
}

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.
	 */
2819 2820 2821 2822 2823 2824
	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);
2825
	memcg_oom_recover(batch->memcg);
2826 2827 2828 2829
	/* forget this pointer (for sanity check) */
	batch->memcg = NULL;
}

2830
#ifdef CONFIG_SWAP
2831
/*
2832
 * called after __delete_from_swap_cache() and drop "page" account.
2833 2834
 * memcg information is recorded to swap_cgroup of "ent"
 */
K
KAMEZAWA Hiroyuki 已提交
2835 2836
void
mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
2837 2838
{
	struct mem_cgroup *memcg;
K
KAMEZAWA Hiroyuki 已提交
2839 2840 2841 2842 2843 2844
	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);
2845

K
KAMEZAWA Hiroyuki 已提交
2846 2847 2848 2849 2850
	/*
	 * record memcg information,  if swapout && memcg != NULL,
	 * mem_cgroup_get() was called in uncharge().
	 */
	if (do_swap_account && swapout && memcg)
2851
		swap_cgroup_record(ent, css_id(&memcg->css));
2852
}
2853
#endif
2854 2855 2856 2857 2858 2859 2860

#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
2861
{
2862
	struct mem_cgroup *memcg;
2863
	unsigned short id;
2864 2865 2866 2867

	if (!do_swap_account)
		return;

2868 2869 2870
	id = swap_cgroup_record(ent, 0);
	rcu_read_lock();
	memcg = mem_cgroup_lookup(id);
2871
	if (memcg) {
2872 2873 2874 2875
		/*
		 * We uncharge this because swap is freed.
		 * This memcg can be obsolete one. We avoid calling css_tryget
		 */
2876
		if (!mem_cgroup_is_root(memcg))
2877
			res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2878
		mem_cgroup_swap_statistics(memcg, false);
2879 2880
		mem_cgroup_put(memcg);
	}
2881
	rcu_read_unlock();
K
KAMEZAWA Hiroyuki 已提交
2882
}
2883 2884 2885 2886 2887 2888

/**
 * 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
2889
 * @need_fixup: whether we should fixup res_counters and refcounts.
2890 2891 2892 2893 2894 2895 2896 2897 2898 2899
 *
 * 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,
2900
		struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2901 2902 2903 2904 2905 2906 2907 2908
{
	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);
2909
		mem_cgroup_swap_statistics(to, true);
2910
		/*
2911 2912 2913 2914 2915 2916
		 * 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.
2917 2918
		 */
		mem_cgroup_get(to);
2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929
		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);
		}
2930 2931 2932 2933 2934 2935
		return 0;
	}
	return -EINVAL;
}
#else
static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
2936
		struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2937 2938 2939
{
	return -EINVAL;
}
2940
#endif
K
KAMEZAWA Hiroyuki 已提交
2941

2942
/*
2943 2944
 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
 * page belongs to.
2945
 */
2946
int mem_cgroup_prepare_migration(struct page *page,
2947
	struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask)
2948
{
2949
	struct mem_cgroup *mem = NULL;
2950
	struct page_cgroup *pc;
2951
	enum charge_type ctype;
2952
	int ret = 0;
2953

2954 2955
	*ptr = NULL;

A
Andrea Arcangeli 已提交
2956
	VM_BUG_ON(PageTransHuge(page));
2957
	if (mem_cgroup_disabled())
2958 2959
		return 0;

2960 2961 2962
	pc = lookup_page_cgroup(page);
	lock_page_cgroup(pc);
	if (PageCgroupUsed(pc)) {
2963 2964
		mem = pc->mem_cgroup;
		css_get(&mem->css);
2965 2966 2967 2968 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
		/*
		 * 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);
2996
	}
2997
	unlock_page_cgroup(pc);
2998 2999 3000 3001 3002 3003
	/*
	 * If the page is not charged at this point,
	 * we return here.
	 */
	if (!mem)
		return 0;
3004

A
Andrea Arcangeli 已提交
3005
	*ptr = mem;
3006
	ret = __mem_cgroup_try_charge(NULL, gfp_mask, 1, ptr, false);
3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018
	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;
3019
	}
3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032
	/*
	 * 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;
3033
	__mem_cgroup_commit_charge(mem, page, 1, pc, ctype);
3034
	return ret;
3035
}
3036

3037
/* remove redundant charge if migration failed*/
3038
void mem_cgroup_end_migration(struct mem_cgroup *mem,
3039
	struct page *oldpage, struct page *newpage, bool migration_ok)
3040
{
3041
	struct page *used, *unused;
3042 3043 3044 3045
	struct page_cgroup *pc;

	if (!mem)
		return;
3046
	/* blocks rmdir() */
3047
	cgroup_exclude_rmdir(&mem->css);
3048
	if (!migration_ok) {
3049 3050
		used = oldpage;
		unused = newpage;
3051
	} else {
3052
		used = newpage;
3053 3054
		unused = oldpage;
	}
3055
	/*
3056 3057 3058
	 * 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.
3059
	 */
3060 3061 3062 3063
	pc = lookup_page_cgroup(oldpage);
	lock_page_cgroup(pc);
	ClearPageCgroupMigration(pc);
	unlock_page_cgroup(pc);
3064

3065 3066
	__mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);

3067
	/*
3068 3069 3070 3071 3072 3073
	 * 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)
3074
	 */
3075 3076
	if (PageAnon(used))
		mem_cgroup_uncharge_page(used);
3077
	/*
3078 3079
	 * At migration, we may charge account against cgroup which has no
	 * tasks.
3080 3081 3082 3083
	 * 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);
3084
}
3085

3086
/*
3087 3088 3089 3090 3091 3092
 * 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.
3093
 */
3094
int mem_cgroup_shmem_charge_fallback(struct page *page,
3095 3096
			    struct mm_struct *mm,
			    gfp_t gfp_mask)
3097
{
3098
	struct mem_cgroup *mem;
3099
	int ret;
3100

3101
	if (mem_cgroup_disabled())
3102
		return 0;
3103

3104 3105 3106
	ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
	if (!ret)
		mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
3107

3108
	return ret;
3109 3110
}

3111 3112 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
#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

3157 3158
static DEFINE_MUTEX(set_limit_mutex);

3159
static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
3160
				unsigned long long val)
3161
{
3162
	int retry_count;
3163
	u64 memswlimit, memlimit;
3164
	int ret = 0;
3165 3166
	int children = mem_cgroup_count_children(memcg);
	u64 curusage, oldusage;
3167
	int enlarge;
3168 3169 3170 3171 3172 3173 3174 3175 3176

	/*
	 * 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);
3177

3178
	enlarge = 0;
3179
	while (retry_count) {
3180 3181 3182 3183
		if (signal_pending(current)) {
			ret = -EINTR;
			break;
		}
3184 3185 3186 3187 3188 3189 3190 3191 3192 3193
		/*
		 * 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);
3194 3195
			break;
		}
3196 3197 3198 3199 3200

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

3201
		ret = res_counter_set_limit(&memcg->res, val);
3202 3203 3204 3205 3206 3207
		if (!ret) {
			if (memswlimit == val)
				memcg->memsw_is_minimum = true;
			else
				memcg->memsw_is_minimum = false;
		}
3208 3209 3210 3211 3212
		mutex_unlock(&set_limit_mutex);

		if (!ret)
			break;

3213
		mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3214
						MEM_CGROUP_RECLAIM_SHRINK);
3215 3216 3217 3218 3219 3220
		curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
		/* Usage is reduced ? */
  		if (curusage >= oldusage)
			retry_count--;
		else
			oldusage = curusage;
3221
	}
3222 3223
	if (!ret && enlarge)
		memcg_oom_recover(memcg);
3224

3225 3226 3227
	return ret;
}

L
Li Zefan 已提交
3228 3229
static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
					unsigned long long val)
3230
{
3231
	int retry_count;
3232
	u64 memlimit, memswlimit, oldusage, curusage;
3233 3234
	int children = mem_cgroup_count_children(memcg);
	int ret = -EBUSY;
3235
	int enlarge = 0;
3236

3237 3238 3239
	/* see mem_cgroup_resize_res_limit */
 	retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
	oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256
	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;
		}
3257 3258 3259
		memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
		if (memswlimit < val)
			enlarge = 1;
3260
		ret = res_counter_set_limit(&memcg->memsw, val);
3261 3262 3263 3264 3265 3266
		if (!ret) {
			if (memlimit == val)
				memcg->memsw_is_minimum = true;
			else
				memcg->memsw_is_minimum = false;
		}
3267 3268 3269 3270 3271
		mutex_unlock(&set_limit_mutex);

		if (!ret)
			break;

3272
		mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3273 3274
						MEM_CGROUP_RECLAIM_NOSWAP |
						MEM_CGROUP_RECLAIM_SHRINK);
3275
		curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3276
		/* Usage is reduced ? */
3277
		if (curusage >= oldusage)
3278
			retry_count--;
3279 3280
		else
			oldusage = curusage;
3281
	}
3282 3283
	if (!ret && enlarge)
		memcg_oom_recover(memcg);
3284 3285 3286
	return ret;
}

3287
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3288
					    gfp_t gfp_mask)
3289 3290 3291 3292 3293 3294
{
	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;
3295
	unsigned long long excess;
3296 3297 3298 3299

	if (order > 0)
		return 0;

3300
	mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347
	/*
	 * This loop can run a while, specially if mem_cgroup's continuously
	 * keep exceeding their soft limit and putting the system under
	 * pressure
	 */
	do {
		if (next_mz)
			mz = next_mz;
		else
			mz = mem_cgroup_largest_soft_limit_node(mctz);
		if (!mz)
			break;

		reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone,
						gfp_mask,
						MEM_CGROUP_RECLAIM_SOFT);
		nr_reclaimed += reclaimed;
		spin_lock(&mctz->lock);

		/*
		 * If we failed to reclaim anything from this memory cgroup
		 * it is time to move on to the next cgroup
		 */
		next_mz = NULL;
		if (!reclaimed) {
			do {
				/*
				 * Loop until we find yet another one.
				 *
				 * By the time we get the soft_limit lock
				 * again, someone might have aded the
				 * group back on the RB tree. Iterate to
				 * make sure we get a different mem.
				 * mem_cgroup_largest_soft_limit_node returns
				 * NULL if no other cgroup is present on
				 * the tree
				 */
				next_mz =
				__mem_cgroup_largest_soft_limit_node(mctz);
				if (next_mz == mz) {
					css_put(&next_mz->mem->css);
					next_mz = NULL;
				} else /* next_mz == NULL or other memcg */
					break;
			} while (1);
		}
		__mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
3348
		excess = res_counter_soft_limit_excess(&mz->mem->res);
3349 3350 3351 3352 3353 3354 3355 3356
		/*
		 * 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.
		 */
3357 3358
		/* If excess == 0, no tree ops */
		__mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess);
3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376
		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;
}

3377 3378 3379 3380
/*
 * This routine traverse page_cgroup in given list and drop them all.
 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
 */
3381
static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
K
KAMEZAWA Hiroyuki 已提交
3382
				int node, int zid, enum lru_list lru)
3383
{
K
KAMEZAWA Hiroyuki 已提交
3384 3385
	struct zone *zone;
	struct mem_cgroup_per_zone *mz;
3386
	struct page_cgroup *pc, *busy;
K
KAMEZAWA Hiroyuki 已提交
3387
	unsigned long flags, loop;
3388
	struct list_head *list;
3389
	int ret = 0;
3390

K
KAMEZAWA Hiroyuki 已提交
3391 3392
	zone = &NODE_DATA(node)->node_zones[zid];
	mz = mem_cgroup_zoneinfo(mem, node, zid);
3393
	list = &mz->lists[lru];
3394

3395 3396 3397 3398 3399
	loop = MEM_CGROUP_ZSTAT(mz, lru);
	/* give some margin against EBUSY etc...*/
	loop += 256;
	busy = NULL;
	while (loop--) {
3400 3401
		struct page *page;

3402
		ret = 0;
K
KAMEZAWA Hiroyuki 已提交
3403
		spin_lock_irqsave(&zone->lru_lock, flags);
3404
		if (list_empty(list)) {
K
KAMEZAWA Hiroyuki 已提交
3405
			spin_unlock_irqrestore(&zone->lru_lock, flags);
3406
			break;
3407 3408 3409 3410
		}
		pc = list_entry(list->prev, struct page_cgroup, lru);
		if (busy == pc) {
			list_move(&pc->lru, list);
3411
			busy = NULL;
K
KAMEZAWA Hiroyuki 已提交
3412
			spin_unlock_irqrestore(&zone->lru_lock, flags);
3413 3414
			continue;
		}
K
KAMEZAWA Hiroyuki 已提交
3415
		spin_unlock_irqrestore(&zone->lru_lock, flags);
3416

3417
		page = lookup_cgroup_page(pc);
3418 3419

		ret = mem_cgroup_move_parent(page, pc, mem, GFP_KERNEL);
3420
		if (ret == -ENOMEM)
3421
			break;
3422 3423 3424 3425 3426 3427 3428

		if (ret == -EBUSY || ret == -EINVAL) {
			/* found lock contention or "pc" is obsolete. */
			busy = pc;
			cond_resched();
		} else
			busy = NULL;
3429
	}
K
KAMEZAWA Hiroyuki 已提交
3430

3431 3432 3433
	if (!ret && !list_empty(list))
		return -EBUSY;
	return ret;
3434 3435 3436 3437 3438 3439
}

/*
 * make mem_cgroup's charge to be 0 if there is no task.
 * This enables deleting this mem_cgroup.
 */
3440
static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
3441
{
3442 3443 3444
	int ret;
	int node, zid, shrink;
	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3445
	struct cgroup *cgrp = mem->css.cgroup;
3446

3447
	css_get(&mem->css);
3448 3449

	shrink = 0;
3450 3451 3452
	/* should free all ? */
	if (free_all)
		goto try_to_free;
3453
move_account:
3454
	do {
3455
		ret = -EBUSY;
3456 3457 3458 3459
		if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
			goto out;
		ret = -EINTR;
		if (signal_pending(current))
3460
			goto out;
3461 3462
		/* This is for making all *used* pages to be on LRU. */
		lru_add_drain_all();
3463
		drain_all_stock_sync();
3464
		ret = 0;
3465
		mem_cgroup_start_move(mem);
3466
		for_each_node_state(node, N_HIGH_MEMORY) {
3467
			for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
3468
				enum lru_list l;
3469 3470
				for_each_lru(l) {
					ret = mem_cgroup_force_empty_list(mem,
K
KAMEZAWA Hiroyuki 已提交
3471
							node, zid, l);
3472 3473 3474
					if (ret)
						break;
				}
3475
			}
3476 3477 3478
			if (ret)
				break;
		}
3479
		mem_cgroup_end_move(mem);
3480
		memcg_oom_recover(mem);
3481 3482 3483
		/* it seems parent cgroup doesn't have enough mem */
		if (ret == -ENOMEM)
			goto try_to_free;
3484
		cond_resched();
3485 3486
	/* "ret" should also be checked to ensure all lists are empty. */
	} while (mem->res.usage > 0 || ret);
3487 3488 3489
out:
	css_put(&mem->css);
	return ret;
3490 3491

try_to_free:
3492 3493
	/* returns EBUSY if there is a task or if we come here twice. */
	if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
3494 3495 3496
		ret = -EBUSY;
		goto out;
	}
3497 3498
	/* we call try-to-free pages for make this cgroup empty */
	lru_add_drain_all();
3499 3500 3501 3502
	/* try to free all pages in this cgroup */
	shrink = 1;
	while (nr_retries && mem->res.usage > 0) {
		int progress;
3503 3504 3505 3506 3507

		if (signal_pending(current)) {
			ret = -EINTR;
			goto out;
		}
K
KOSAKI Motohiro 已提交
3508 3509
		progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
						false, get_swappiness(mem));
3510
		if (!progress) {
3511
			nr_retries--;
3512
			/* maybe some writeback is necessary */
3513
			congestion_wait(BLK_RW_ASYNC, HZ/10);
3514
		}
3515 3516

	}
K
KAMEZAWA Hiroyuki 已提交
3517
	lru_add_drain();
3518
	/* try move_account...there may be some *locked* pages. */
3519
	goto move_account;
3520 3521
}

3522 3523 3524 3525 3526 3527
int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
{
	return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
}


3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545
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();
	/*
3546
	 * If parent's use_hierarchy is set, we can't make any modifications
3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565
	 * 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;
}

3566

3567 3568
static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *mem,
					       enum mem_cgroup_stat_index idx)
3569
{
K
KAMEZAWA Hiroyuki 已提交
3570
	struct mem_cgroup *iter;
3571
	long val = 0;
3572

3573
	/* Per-cpu values can be negative, use a signed accumulator */
K
KAMEZAWA Hiroyuki 已提交
3574 3575 3576 3577 3578 3579
	for_each_mem_cgroup_tree(iter, mem)
		val += mem_cgroup_read_stat(iter, idx);

	if (val < 0) /* race ? */
		val = 0;
	return val;
3580 3581
}

3582 3583
static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap)
{
K
KAMEZAWA Hiroyuki 已提交
3584
	u64 val;
3585 3586 3587 3588 3589 3590 3591 3592

	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);
	}

3593 3594
	val = mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_CACHE);
	val += mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_RSS);
3595

K
KAMEZAWA Hiroyuki 已提交
3596
	if (swap)
3597
		val += mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
3598 3599 3600 3601

	return val << PAGE_SHIFT;
}

3602
static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
B
Balbir Singh 已提交
3603
{
3604
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3605
	u64 val;
3606 3607 3608 3609 3610 3611
	int type, name;

	type = MEMFILE_TYPE(cft->private);
	name = MEMFILE_ATTR(cft->private);
	switch (type) {
	case _MEM:
3612 3613 3614
		if (name == RES_USAGE)
			val = mem_cgroup_usage(mem, false);
		else
3615
			val = res_counter_read_u64(&mem->res, name);
3616 3617
		break;
	case _MEMSWAP:
3618 3619 3620
		if (name == RES_USAGE)
			val = mem_cgroup_usage(mem, true);
		else
3621
			val = res_counter_read_u64(&mem->memsw, name);
3622 3623 3624 3625 3626 3627
		break;
	default:
		BUG();
		break;
	}
	return val;
B
Balbir Singh 已提交
3628
}
3629 3630 3631 3632
/*
 * The user of this function is...
 * RES_LIMIT.
 */
3633 3634
static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
			    const char *buffer)
B
Balbir Singh 已提交
3635
{
3636
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3637
	int type, name;
3638 3639 3640
	unsigned long long val;
	int ret;

3641 3642 3643
	type = MEMFILE_TYPE(cft->private);
	name = MEMFILE_ATTR(cft->private);
	switch (name) {
3644
	case RES_LIMIT:
3645 3646 3647 3648
		if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
			ret = -EINVAL;
			break;
		}
3649 3650
		/* This function does all necessary parse...reuse it */
		ret = res_counter_memparse_write_strategy(buffer, &val);
3651 3652 3653
		if (ret)
			break;
		if (type == _MEM)
3654
			ret = mem_cgroup_resize_limit(memcg, val);
3655 3656
		else
			ret = mem_cgroup_resize_memsw_limit(memcg, val);
3657
		break;
3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671
	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;
3672 3673 3674 3675 3676
	default:
		ret = -EINVAL; /* should be BUG() ? */
		break;
	}
	return ret;
B
Balbir Singh 已提交
3677 3678
}

3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706
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;
}

3707
static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
3708 3709
{
	struct mem_cgroup *mem;
3710
	int type, name;
3711 3712

	mem = mem_cgroup_from_cont(cont);
3713 3714 3715
	type = MEMFILE_TYPE(event);
	name = MEMFILE_ATTR(event);
	switch (name) {
3716
	case RES_MAX_USAGE:
3717 3718 3719 3720
		if (type == _MEM)
			res_counter_reset_max(&mem->res);
		else
			res_counter_reset_max(&mem->memsw);
3721 3722
		break;
	case RES_FAILCNT:
3723 3724 3725 3726
		if (type == _MEM)
			res_counter_reset_failcnt(&mem->res);
		else
			res_counter_reset_failcnt(&mem->memsw);
3727 3728
		break;
	}
3729

3730
	return 0;
3731 3732
}

3733 3734 3735 3736 3737 3738
static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
					struct cftype *cft)
{
	return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
}

3739
#ifdef CONFIG_MMU
3740 3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755 3756 3757
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;
}
3758 3759 3760 3761 3762 3763 3764
#else
static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
					struct cftype *cft, u64 val)
{
	return -ENOSYS;
}
#endif
3765

K
KAMEZAWA Hiroyuki 已提交
3766 3767 3768 3769 3770

/* For read statistics */
enum {
	MCS_CACHE,
	MCS_RSS,
3771
	MCS_FILE_MAPPED,
K
KAMEZAWA Hiroyuki 已提交
3772 3773
	MCS_PGPGIN,
	MCS_PGPGOUT,
3774
	MCS_SWAP,
K
KAMEZAWA Hiroyuki 已提交
3775 3776 3777 3778 3779 3780 3781 3782 3783 3784
	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];
3785 3786
};

K
KAMEZAWA Hiroyuki 已提交
3787 3788 3789 3790 3791 3792
struct {
	char *local_name;
	char *total_name;
} memcg_stat_strings[NR_MCS_STAT] = {
	{"cache", "total_cache"},
	{"rss", "total_rss"},
3793
	{"mapped_file", "total_mapped_file"},
K
KAMEZAWA Hiroyuki 已提交
3794 3795
	{"pgpgin", "total_pgpgin"},
	{"pgpgout", "total_pgpgout"},
3796
	{"swap", "total_swap"},
K
KAMEZAWA Hiroyuki 已提交
3797 3798 3799 3800 3801 3802 3803 3804
	{"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
3805 3806
static void
mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
K
KAMEZAWA Hiroyuki 已提交
3807 3808 3809 3810
{
	s64 val;

	/* per cpu stat */
3811
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
K
KAMEZAWA Hiroyuki 已提交
3812
	s->stat[MCS_CACHE] += val * PAGE_SIZE;
3813
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
K
KAMEZAWA Hiroyuki 已提交
3814
	s->stat[MCS_RSS] += val * PAGE_SIZE;
3815
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED);
3816
	s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
3817
	val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGPGIN);
K
KAMEZAWA Hiroyuki 已提交
3818
	s->stat[MCS_PGPGIN] += val;
3819
	val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGPGOUT);
K
KAMEZAWA Hiroyuki 已提交
3820
	s->stat[MCS_PGPGOUT] += val;
3821
	if (do_swap_account) {
3822
		val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
3823 3824
		s->stat[MCS_SWAP] += val * PAGE_SIZE;
	}
K
KAMEZAWA Hiroyuki 已提交
3825 3826 3827 3828 3829 3830 3831 3832 3833 3834 3835 3836 3837 3838 3839 3840 3841

	/* 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
3842 3843 3844 3845
	struct mem_cgroup *iter;

	for_each_mem_cgroup_tree(iter, mem)
		mem_cgroup_get_local_stat(iter, s);
K
KAMEZAWA Hiroyuki 已提交
3846 3847
}

3848 3849
static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
				 struct cgroup_map_cb *cb)
3850 3851
{
	struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
K
KAMEZAWA Hiroyuki 已提交
3852
	struct mcs_total_stat mystat;
3853 3854
	int i;

K
KAMEZAWA Hiroyuki 已提交
3855 3856
	memset(&mystat, 0, sizeof(mystat));
	mem_cgroup_get_local_stat(mem_cont, &mystat);
3857

3858 3859 3860
	for (i = 0; i < NR_MCS_STAT; i++) {
		if (i == MCS_SWAP && !do_swap_account)
			continue;
K
KAMEZAWA Hiroyuki 已提交
3861
		cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
3862
	}
L
Lee Schermerhorn 已提交
3863

K
KAMEZAWA Hiroyuki 已提交
3864
	/* Hierarchical information */
3865 3866 3867 3868 3869 3870 3871
	{
		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
3872

K
KAMEZAWA Hiroyuki 已提交
3873 3874
	memset(&mystat, 0, sizeof(mystat));
	mem_cgroup_get_total_stat(mem_cont, &mystat);
3875 3876 3877
	for (i = 0; i < NR_MCS_STAT; i++) {
		if (i == MCS_SWAP && !do_swap_account)
			continue;
K
KAMEZAWA Hiroyuki 已提交
3878
		cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
3879
	}
K
KAMEZAWA Hiroyuki 已提交
3880

K
KOSAKI Motohiro 已提交
3881
#ifdef CONFIG_DEBUG_VM
3882
	cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
K
KOSAKI Motohiro 已提交
3883 3884 3885 3886 3887 3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907 3908 3909

	{
		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

3910 3911 3912
	return 0;
}

K
KOSAKI Motohiro 已提交
3913 3914 3915 3916 3917 3918 3919 3920 3921 3922 3923 3924
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;
3925

K
KOSAKI Motohiro 已提交
3926 3927 3928 3929 3930 3931 3932
	if (val > 100)
		return -EINVAL;

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

	parent = mem_cgroup_from_cont(cgrp->parent);
3933 3934 3935

	cgroup_lock();

K
KOSAKI Motohiro 已提交
3936 3937
	/* If under hierarchy, only empty-root can set this value */
	if ((parent->use_hierarchy) ||
3938 3939
	    (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
		cgroup_unlock();
K
KOSAKI Motohiro 已提交
3940
		return -EINVAL;
3941
	}
K
KOSAKI Motohiro 已提交
3942 3943 3944

	memcg->swappiness = val;

3945 3946
	cgroup_unlock();

K
KOSAKI Motohiro 已提交
3947 3948 3949
	return 0;
}

3950 3951 3952 3953 3954 3955 3956 3957
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)
3958
		t = rcu_dereference(memcg->thresholds.primary);
3959
	else
3960
		t = rcu_dereference(memcg->memsw_thresholds.primary);
3961 3962 3963 3964 3965 3966 3967 3968 3969 3970 3971

	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().
	 */
3972
	i = t->current_threshold;
3973 3974 3975 3976 3977 3978 3979 3980 3981 3982 3983 3984 3985 3986 3987 3988 3989 3990 3991 3992 3993 3994 3995

	/*
	 * 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 */
3996
	t->current_threshold = i - 1;
3997 3998 3999 4000 4001 4002
unlock:
	rcu_read_unlock();
}

static void mem_cgroup_threshold(struct mem_cgroup *memcg)
{
4003 4004 4005 4006 4007 4008 4009
	while (memcg) {
		__mem_cgroup_threshold(memcg, false);
		if (do_swap_account)
			__mem_cgroup_threshold(memcg, true);

		memcg = parent_mem_cgroup(memcg);
	}
4010 4011 4012 4013 4014 4015 4016 4017 4018 4019
}

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
4020
static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem)
K
KAMEZAWA Hiroyuki 已提交
4021 4022 4023 4024 4025 4026 4027 4028 4029 4030
{
	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
4031 4032 4033 4034
	struct mem_cgroup *iter;

	for_each_mem_cgroup_tree(iter, mem)
		mem_cgroup_oom_notify_cb(iter);
K
KAMEZAWA Hiroyuki 已提交
4035 4036 4037 4038
}

static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
	struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
4039 4040
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4041 4042
	struct mem_cgroup_thresholds *thresholds;
	struct mem_cgroup_threshold_ary *new;
4043 4044
	int type = MEMFILE_TYPE(cft->private);
	u64 threshold, usage;
4045
	int i, size, ret;
4046 4047 4048 4049 4050 4051

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

	mutex_lock(&memcg->thresholds_lock);
4052

4053
	if (type == _MEM)
4054
		thresholds = &memcg->thresholds;
4055
	else if (type == _MEMSWAP)
4056
		thresholds = &memcg->memsw_thresholds;
4057 4058 4059 4060 4061 4062
	else
		BUG();

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

	/* Check if a threshold crossed before adding a new one */
4063
	if (thresholds->primary)
4064 4065
		__mem_cgroup_threshold(memcg, type == _MEMSWAP);

4066
	size = thresholds->primary ? thresholds->primary->size + 1 : 1;
4067 4068

	/* Allocate memory for new array of thresholds */
4069
	new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
4070
			GFP_KERNEL);
4071
	if (!new) {
4072 4073 4074
		ret = -ENOMEM;
		goto unlock;
	}
4075
	new->size = size;
4076 4077

	/* Copy thresholds (if any) to new array */
4078 4079
	if (thresholds->primary) {
		memcpy(new->entries, thresholds->primary->entries, (size - 1) *
4080
				sizeof(struct mem_cgroup_threshold));
4081 4082
	}

4083
	/* Add new threshold */
4084 4085
	new->entries[size - 1].eventfd = eventfd;
	new->entries[size - 1].threshold = threshold;
4086 4087

	/* Sort thresholds. Registering of new threshold isn't time-critical */
4088
	sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
4089 4090 4091
			compare_thresholds, NULL);

	/* Find current threshold */
4092
	new->current_threshold = -1;
4093
	for (i = 0; i < size; i++) {
4094
		if (new->entries[i].threshold < usage) {
4095
			/*
4096 4097
			 * new->current_threshold will not be used until
			 * rcu_assign_pointer(), so it's safe to increment
4098 4099
			 * it here.
			 */
4100
			++new->current_threshold;
4101 4102 4103
		}
	}

4104 4105 4106 4107 4108
	/* Free old spare buffer and save old primary buffer as spare */
	kfree(thresholds->spare);
	thresholds->spare = thresholds->primary;

	rcu_assign_pointer(thresholds->primary, new);
4109

4110
	/* To be sure that nobody uses thresholds */
4111 4112 4113 4114 4115 4116 4117 4118
	synchronize_rcu();

unlock:
	mutex_unlock(&memcg->thresholds_lock);

	return ret;
}

4119
static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
K
KAMEZAWA Hiroyuki 已提交
4120
	struct cftype *cft, struct eventfd_ctx *eventfd)
4121 4122
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4123 4124
	struct mem_cgroup_thresholds *thresholds;
	struct mem_cgroup_threshold_ary *new;
4125 4126
	int type = MEMFILE_TYPE(cft->private);
	u64 usage;
4127
	int i, j, size;
4128 4129 4130

	mutex_lock(&memcg->thresholds_lock);
	if (type == _MEM)
4131
		thresholds = &memcg->thresholds;
4132
	else if (type == _MEMSWAP)
4133
		thresholds = &memcg->memsw_thresholds;
4134 4135 4136 4137 4138 4139 4140 4141 4142 4143 4144 4145 4146 4147 4148
	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 */
4149 4150 4151
	size = 0;
	for (i = 0; i < thresholds->primary->size; i++) {
		if (thresholds->primary->entries[i].eventfd != eventfd)
4152 4153 4154
			size++;
	}

4155
	new = thresholds->spare;
4156

4157 4158
	/* Set thresholds array to NULL if we don't have thresholds */
	if (!size) {
4159 4160
		kfree(new);
		new = NULL;
4161
		goto swap_buffers;
4162 4163
	}

4164
	new->size = size;
4165 4166

	/* Copy thresholds and find current threshold */
4167 4168 4169
	new->current_threshold = -1;
	for (i = 0, j = 0; i < thresholds->primary->size; i++) {
		if (thresholds->primary->entries[i].eventfd == eventfd)
4170 4171
			continue;

4172 4173
		new->entries[j] = thresholds->primary->entries[i];
		if (new->entries[j].threshold < usage) {
4174
			/*
4175
			 * new->current_threshold will not be used
4176 4177 4178
			 * until rcu_assign_pointer(), so it's safe to increment
			 * it here.
			 */
4179
			++new->current_threshold;
4180 4181 4182 4183
		}
		j++;
	}

4184
swap_buffers:
4185 4186 4187
	/* Swap primary and spare array */
	thresholds->spare = thresholds->primary;
	rcu_assign_pointer(thresholds->primary, new);
4188

4189
	/* To be sure that nobody uses thresholds */
4190 4191 4192 4193
	synchronize_rcu();

	mutex_unlock(&memcg->thresholds_lock);
}
4194

K
KAMEZAWA Hiroyuki 已提交
4195 4196 4197 4198 4199 4200 4201 4202 4203 4204 4205 4206 4207 4208 4209 4210 4211 4212 4213 4214 4215 4216 4217 4218 4219
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;
}

4220
static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
K
KAMEZAWA Hiroyuki 已提交
4221 4222 4223 4224 4225 4226 4227 4228 4229 4230 4231 4232 4233 4234 4235 4236 4237 4238 4239 4240
	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);
}

4241 4242 4243 4244 4245 4246 4247 4248 4249 4250 4251 4252 4253 4254 4255 4256 4257 4258 4259 4260 4261 4262 4263 4264 4265 4266 4267 4268 4269 4270 4271 4272 4273 4274
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;
4275 4276
	if (!val)
		memcg_oom_recover(mem);
4277 4278 4279 4280
	cgroup_unlock();
	return 0;
}

B
Balbir Singh 已提交
4281 4282
static struct cftype mem_cgroup_files[] = {
	{
4283
		.name = "usage_in_bytes",
4284
		.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4285
		.read_u64 = mem_cgroup_read,
K
KAMEZAWA Hiroyuki 已提交
4286 4287
		.register_event = mem_cgroup_usage_register_event,
		.unregister_event = mem_cgroup_usage_unregister_event,
B
Balbir Singh 已提交
4288
	},
4289 4290
	{
		.name = "max_usage_in_bytes",
4291
		.private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4292
		.trigger = mem_cgroup_reset,
4293 4294
		.read_u64 = mem_cgroup_read,
	},
B
Balbir Singh 已提交
4295
	{
4296
		.name = "limit_in_bytes",
4297
		.private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4298
		.write_string = mem_cgroup_write,
4299
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
4300
	},
4301 4302 4303 4304 4305 4306
	{
		.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
4307 4308
	{
		.name = "failcnt",
4309
		.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4310
		.trigger = mem_cgroup_reset,
4311
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
4312
	},
4313 4314
	{
		.name = "stat",
4315
		.read_map = mem_control_stat_show,
4316
	},
4317 4318 4319 4320
	{
		.name = "force_empty",
		.trigger = mem_cgroup_force_empty_write,
	},
4321 4322 4323 4324 4325
	{
		.name = "use_hierarchy",
		.write_u64 = mem_cgroup_hierarchy_write,
		.read_u64 = mem_cgroup_hierarchy_read,
	},
K
KOSAKI Motohiro 已提交
4326 4327 4328 4329 4330
	{
		.name = "swappiness",
		.read_u64 = mem_cgroup_swappiness_read,
		.write_u64 = mem_cgroup_swappiness_write,
	},
4331 4332 4333 4334 4335
	{
		.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
4336 4337
	{
		.name = "oom_control",
4338 4339
		.read_map = mem_cgroup_oom_control_read,
		.write_u64 = mem_cgroup_oom_control_write,
K
KAMEZAWA Hiroyuki 已提交
4340 4341 4342 4343
		.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
4344 4345
};

4346 4347 4348 4349 4350 4351
#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
4352 4353
		.register_event = mem_cgroup_usage_register_event,
		.unregister_event = mem_cgroup_usage_unregister_event,
4354 4355 4356 4357 4358 4359 4360 4361 4362 4363 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
	},
	{
		.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

4389 4390 4391
static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
	struct mem_cgroup_per_node *pn;
4392
	struct mem_cgroup_per_zone *mz;
4393
	enum lru_list l;
4394
	int zone, tmp = node;
4395 4396 4397 4398 4399 4400 4401 4402
	/*
	 * 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.
	 */
4403 4404
	if (!node_state(node, N_NORMAL_MEMORY))
		tmp = -1;
4405
	pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4406 4407
	if (!pn)
		return 1;
4408

4409
	mem->info.nodeinfo[node] = pn;
4410 4411
	for (zone = 0; zone < MAX_NR_ZONES; zone++) {
		mz = &pn->zoneinfo[zone];
4412 4413
		for_each_lru(l)
			INIT_LIST_HEAD(&mz->lists[l]);
4414
		mz->usage_in_excess = 0;
4415 4416
		mz->on_tree = false;
		mz->mem = mem;
4417
	}
4418 4419 4420
	return 0;
}

4421 4422 4423 4424 4425
static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
	kfree(mem->info.nodeinfo[node]);
}

4426 4427 4428
static struct mem_cgroup *mem_cgroup_alloc(void)
{
	struct mem_cgroup *mem;
4429
	int size = sizeof(struct mem_cgroup);
4430

4431
	/* Can be very big if MAX_NUMNODES is very big */
4432
	if (size < PAGE_SIZE)
4433
		mem = kzalloc(size, GFP_KERNEL);
4434
	else
4435
		mem = vzalloc(size);
4436

4437 4438 4439
	if (!mem)
		return NULL;

4440
	mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4441 4442
	if (!mem->stat)
		goto out_free;
4443
	spin_lock_init(&mem->pcp_counter_lock);
4444
	return mem;
4445 4446 4447 4448 4449 4450 4451

out_free:
	if (size < PAGE_SIZE)
		kfree(mem);
	else
		vfree(mem);
	return NULL;
4452 4453
}

4454 4455 4456 4457 4458 4459 4460 4461 4462 4463 4464
/*
 * 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.
 */

4465
static void __mem_cgroup_free(struct mem_cgroup *mem)
4466
{
K
KAMEZAWA Hiroyuki 已提交
4467 4468
	int node;

4469
	mem_cgroup_remove_from_trees(mem);
K
KAMEZAWA Hiroyuki 已提交
4470 4471
	free_css_id(&mem_cgroup_subsys, &mem->css);

K
KAMEZAWA Hiroyuki 已提交
4472 4473 4474
	for_each_node_state(node, N_POSSIBLE)
		free_mem_cgroup_per_zone_info(mem, node);

4475 4476
	free_percpu(mem->stat);
	if (sizeof(struct mem_cgroup) < PAGE_SIZE)
4477 4478 4479 4480 4481
		kfree(mem);
	else
		vfree(mem);
}

4482 4483 4484 4485 4486
static void mem_cgroup_get(struct mem_cgroup *mem)
{
	atomic_inc(&mem->refcnt);
}

4487
static void __mem_cgroup_put(struct mem_cgroup *mem, int count)
4488
{
4489
	if (atomic_sub_and_test(count, &mem->refcnt)) {
4490
		struct mem_cgroup *parent = parent_mem_cgroup(mem);
4491
		__mem_cgroup_free(mem);
4492 4493 4494
		if (parent)
			mem_cgroup_put(parent);
	}
4495 4496
}

4497 4498 4499 4500 4501
static void mem_cgroup_put(struct mem_cgroup *mem)
{
	__mem_cgroup_put(mem, 1);
}

4502 4503 4504 4505 4506 4507 4508 4509 4510
/*
 * 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);
}
4511

4512 4513 4514
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
static void __init enable_swap_cgroup(void)
{
4515
	if (!mem_cgroup_disabled() && really_do_swap_account)
4516 4517 4518 4519 4520 4521 4522 4523
		do_swap_account = 1;
}
#else
static void __init enable_swap_cgroup(void)
{
}
#endif

4524 4525 4526 4527 4528 4529 4530 4531 4532 4533 4534 4535 4536 4537 4538 4539 4540 4541 4542 4543 4544 4545 4546 4547 4548
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
4549
static struct cgroup_subsys_state * __ref
B
Balbir Singh 已提交
4550 4551
mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
{
4552
	struct mem_cgroup *mem, *parent;
K
KAMEZAWA Hiroyuki 已提交
4553
	long error = -ENOMEM;
4554
	int node;
B
Balbir Singh 已提交
4555

4556 4557
	mem = mem_cgroup_alloc();
	if (!mem)
K
KAMEZAWA Hiroyuki 已提交
4558
		return ERR_PTR(error);
4559

4560 4561 4562
	for_each_node_state(node, N_POSSIBLE)
		if (alloc_mem_cgroup_per_zone_info(mem, node))
			goto free_out;
4563

4564
	/* root ? */
4565
	if (cont->parent == NULL) {
4566
		int cpu;
4567
		enable_swap_cgroup();
4568
		parent = NULL;
4569
		root_mem_cgroup = mem;
4570 4571
		if (mem_cgroup_soft_limit_tree_init())
			goto free_out;
4572 4573 4574 4575 4576
		for_each_possible_cpu(cpu) {
			struct memcg_stock_pcp *stock =
						&per_cpu(memcg_stock, cpu);
			INIT_WORK(&stock->work, drain_local_stock);
		}
4577
		hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
4578
	} else {
4579
		parent = mem_cgroup_from_cont(cont->parent);
4580
		mem->use_hierarchy = parent->use_hierarchy;
4581
		mem->oom_kill_disable = parent->oom_kill_disable;
4582
	}
4583

4584 4585 4586
	if (parent && parent->use_hierarchy) {
		res_counter_init(&mem->res, &parent->res);
		res_counter_init(&mem->memsw, &parent->memsw);
4587 4588 4589 4590 4591 4592 4593
		/*
		 * 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);
4594 4595 4596 4597
	} else {
		res_counter_init(&mem->res, NULL);
		res_counter_init(&mem->memsw, NULL);
	}
K
KAMEZAWA Hiroyuki 已提交
4598
	mem->last_scanned_child = 0;
K
KAMEZAWA Hiroyuki 已提交
4599
	INIT_LIST_HEAD(&mem->oom_notify);
4600

K
KOSAKI Motohiro 已提交
4601 4602
	if (parent)
		mem->swappiness = get_swappiness(parent);
4603
	atomic_set(&mem->refcnt, 1);
4604
	mem->move_charge_at_immigrate = 0;
4605
	mutex_init(&mem->thresholds_lock);
B
Balbir Singh 已提交
4606
	return &mem->css;
4607
free_out:
4608
	__mem_cgroup_free(mem);
4609
	root_mem_cgroup = NULL;
K
KAMEZAWA Hiroyuki 已提交
4610
	return ERR_PTR(error);
B
Balbir Singh 已提交
4611 4612
}

4613
static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
4614 4615 4616
					struct cgroup *cont)
{
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4617 4618

	return mem_cgroup_force_empty(mem, false);
4619 4620
}

B
Balbir Singh 已提交
4621 4622 4623
static void mem_cgroup_destroy(struct cgroup_subsys *ss,
				struct cgroup *cont)
{
4624 4625 4626
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);

	mem_cgroup_put(mem);
B
Balbir Singh 已提交
4627 4628 4629 4630 4631
}

static int mem_cgroup_populate(struct cgroup_subsys *ss,
				struct cgroup *cont)
{
4632 4633 4634 4635 4636 4637 4638 4639
	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
4640 4641
}

4642
#ifdef CONFIG_MMU
4643
/* Handlers for move charge at task migration. */
4644 4645
#define PRECHARGE_COUNT_AT_ONCE	256
static int mem_cgroup_do_precharge(unsigned long count)
4646
{
4647 4648
	int ret = 0;
	int batch_count = PRECHARGE_COUNT_AT_ONCE;
4649 4650
	struct mem_cgroup *mem = mc.to;

4651 4652 4653 4654 4655 4656 4657 4658 4659 4660 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
	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();
		}
4686
		ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, 1, &mem, false);
4687 4688 4689 4690 4691
		if (ret || !mem)
			/* mem_cgroup_clear_mc() will do uncharge later */
			return -ENOMEM;
		mc.precharge++;
	}
4692 4693 4694 4695 4696 4697 4698 4699
	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
4700
 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4701 4702 4703 4704 4705 4706
 *
 * 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).
4707 4708 4709
 *   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.
4710 4711 4712 4713 4714
 *
 * Called with pte lock held.
 */
union mc_target {
	struct page	*page;
4715
	swp_entry_t	ent;
4716 4717 4718 4719 4720
};

enum mc_target_type {
	MC_TARGET_NONE,	/* not used */
	MC_TARGET_PAGE,
4721
	MC_TARGET_SWAP,
4722 4723
};

D
Daisuke Nishimura 已提交
4724 4725
static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
						unsigned long addr, pte_t ptent)
4726
{
D
Daisuke Nishimura 已提交
4727
	struct page *page = vm_normal_page(vma, addr, ptent);
4728

D
Daisuke Nishimura 已提交
4729 4730 4731 4732 4733 4734
	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;
4735 4736
	} else if (!move_file())
		/* we ignore mapcount for file pages */
D
Daisuke Nishimura 已提交
4737 4738 4739 4740 4741 4742 4743 4744 4745 4746 4747 4748 4749 4750 4751 4752 4753 4754
		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 */
4755 4756
		if (page)
			put_page(page);
D
Daisuke Nishimura 已提交
4757
		return NULL;
4758
	}
D
Daisuke Nishimura 已提交
4759 4760 4761 4762 4763 4764
	if (do_swap_account)
		entry->val = ent.val;

	return page;
}

4765 4766 4767 4768 4769 4770 4771 4772 4773 4774 4775 4776 4777 4778 4779 4780 4781 4782 4783 4784 4785 4786 4787 4788 4789 4790 4791 4792 4793 4794 4795 4796 4797
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
4798 4799 4800 4801 4802 4803 4804 4805 4806 4807 4808 4809
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);
4810 4811
	else if (pte_none(ptent) || pte_file(ptent))
		page = mc_handle_file_pte(vma, addr, ptent, &ent);
D
Daisuke Nishimura 已提交
4812 4813 4814

	if (!page && !ent.val)
		return 0;
4815 4816 4817 4818 4819 4820 4821 4822 4823 4824 4825 4826 4827 4828 4829
	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
4830 4831
	/* There is a swap entry and a page doesn't exist or isn't charged */
	if (ent.val && !ret &&
4832 4833 4834 4835
			css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
		ret = MC_TARGET_SWAP;
		if (target)
			target->ent = ent;
4836 4837 4838 4839 4840 4841 4842 4843 4844 4845 4846 4847
	}
	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;

4848 4849
	split_huge_page_pmd(walk->mm, pmd);

4850 4851 4852 4853 4854 4855 4856
	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();

4857 4858 4859
	return 0;
}

4860 4861 4862 4863 4864
static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
{
	unsigned long precharge;
	struct vm_area_struct *vma;

4865
	down_read(&mm->mmap_sem);
4866 4867 4868 4869 4870 4871 4872 4873 4874 4875 4876
	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);
	}
4877
	up_read(&mm->mmap_sem);
4878 4879 4880 4881 4882 4883 4884 4885 4886

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

	return precharge;
}

static int mem_cgroup_precharge_mc(struct mm_struct *mm)
{
4887 4888 4889 4890 4891
	unsigned long precharge = mem_cgroup_count_precharge(mm);

	VM_BUG_ON(mc.moving_task);
	mc.moving_task = current;
	return mem_cgroup_do_precharge(precharge);
4892 4893
}

4894 4895
/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
static void __mem_cgroup_clear_mc(void)
4896
{
4897 4898 4899
	struct mem_cgroup *from = mc.from;
	struct mem_cgroup *to = mc.to;

4900
	/* we must uncharge all the leftover precharges from mc.to */
4901 4902 4903 4904 4905 4906 4907 4908 4909 4910 4911
	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;
4912
	}
4913 4914 4915 4916 4917 4918 4919 4920 4921 4922 4923 4924 4925 4926 4927 4928 4929 4930 4931
	/* 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;
	}
4932 4933 4934 4935 4936 4937 4938 4939 4940 4941 4942 4943 4944 4945 4946
	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();
4947
	spin_lock(&mc.lock);
4948 4949
	mc.from = NULL;
	mc.to = NULL;
4950
	spin_unlock(&mc.lock);
4951
	mem_cgroup_end_move(from);
4952 4953
}

4954 4955 4956 4957 4958 4959 4960 4961 4962 4963 4964 4965 4966 4967 4968 4969 4970 4971
static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
				struct cgroup *cgroup,
				struct task_struct *p,
				bool threadgroup)
{
	int ret = 0;
	struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup);

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

		VM_BUG_ON(from == mem);

		mm = get_task_mm(p);
		if (!mm)
			return 0;
		/* We move charges only when we move a owner of the mm */
4972 4973 4974 4975
		if (mm->owner == p) {
			VM_BUG_ON(mc.from);
			VM_BUG_ON(mc.to);
			VM_BUG_ON(mc.precharge);
4976
			VM_BUG_ON(mc.moved_charge);
4977
			VM_BUG_ON(mc.moved_swap);
4978
			mem_cgroup_start_move(from);
4979
			spin_lock(&mc.lock);
4980 4981
			mc.from = from;
			mc.to = mem;
4982
			spin_unlock(&mc.lock);
4983
			/* We set mc.moving_task later */
4984 4985 4986 4987

			ret = mem_cgroup_precharge_mc(mm);
			if (ret)
				mem_cgroup_clear_mc();
4988 4989
		}
		mmput(mm);
4990 4991 4992 4993 4994 4995 4996 4997 4998
	}
	return ret;
}

static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
				struct cgroup *cgroup,
				struct task_struct *p,
				bool threadgroup)
{
4999
	mem_cgroup_clear_mc();
5000 5001
}

5002 5003 5004
static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
				unsigned long addr, unsigned long end,
				struct mm_walk *walk)
5005
{
5006 5007 5008 5009 5010
	int ret = 0;
	struct vm_area_struct *vma = walk->private;
	pte_t *pte;
	spinlock_t *ptl;

5011
	split_huge_page_pmd(walk->mm, pmd);
5012 5013 5014 5015 5016 5017 5018 5019
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;
5020
		swp_entry_t ent;
5021 5022 5023 5024 5025 5026 5027 5028 5029 5030 5031

		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);
5032 5033
			if (!mem_cgroup_move_account(page, 1, pc,
						     mc.from, mc.to, false)) {
5034
				mc.precharge--;
5035 5036
				/* we uncharge from mc.from later. */
				mc.moved_charge++;
5037 5038 5039 5040 5041
			}
			putback_lru_page(page);
put:			/* is_target_pte_for_mc() gets the page */
			put_page(page);
			break;
5042 5043
		case MC_TARGET_SWAP:
			ent = target.ent;
5044 5045
			if (!mem_cgroup_move_swap_account(ent,
						mc.from, mc.to, false)) {
5046
				mc.precharge--;
5047 5048 5049
				/* we fixup refcnts and charges later. */
				mc.moved_swap++;
			}
5050
			break;
5051 5052 5053 5054 5055 5056 5057 5058 5059 5060 5061 5062 5063 5064
		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.
		 */
5065
		ret = mem_cgroup_do_precharge(1);
5066 5067 5068 5069 5070 5071 5072 5073 5074 5075 5076 5077
		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();
5078 5079 5080 5081 5082 5083 5084 5085 5086 5087 5088 5089 5090
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;
	}
5091 5092 5093 5094 5095 5096 5097 5098 5099 5100 5101 5102 5103 5104 5105 5106 5107 5108
	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;
	}
5109
	up_read(&mm->mmap_sem);
5110 5111
}

B
Balbir Singh 已提交
5112 5113 5114
static void mem_cgroup_move_task(struct cgroup_subsys *ss,
				struct cgroup *cont,
				struct cgroup *old_cont,
5115 5116
				struct task_struct *p,
				bool threadgroup)
B
Balbir Singh 已提交
5117
{
5118 5119 5120
	struct mm_struct *mm;

	if (!mc.to)
5121 5122 5123
		/* no need to move charge */
		return;

5124 5125 5126 5127 5128
	mm = get_task_mm(p);
	if (mm) {
		mem_cgroup_move_charge(mm);
		mmput(mm);
	}
5129
	mem_cgroup_clear_mc();
B
Balbir Singh 已提交
5130
}
5131 5132 5133 5134 5135 5136 5137 5138 5139 5140 5141 5142 5143 5144 5145 5146 5147 5148 5149 5150 5151 5152
#else	/* !CONFIG_MMU */
static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
				struct cgroup *cgroup,
				struct task_struct *p,
				bool threadgroup)
{
	return 0;
}
static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
				struct cgroup *cgroup,
				struct task_struct *p,
				bool threadgroup)
{
}
static void mem_cgroup_move_task(struct cgroup_subsys *ss,
				struct cgroup *cont,
				struct cgroup *old_cont,
				struct task_struct *p,
				bool threadgroup)
{
}
#endif
B
Balbir Singh 已提交
5153

B
Balbir Singh 已提交
5154 5155 5156 5157
struct cgroup_subsys mem_cgroup_subsys = {
	.name = "memory",
	.subsys_id = mem_cgroup_subsys_id,
	.create = mem_cgroup_create,
5158
	.pre_destroy = mem_cgroup_pre_destroy,
B
Balbir Singh 已提交
5159 5160
	.destroy = mem_cgroup_destroy,
	.populate = mem_cgroup_populate,
5161 5162
	.can_attach = mem_cgroup_can_attach,
	.cancel_attach = mem_cgroup_cancel_attach,
B
Balbir Singh 已提交
5163
	.attach = mem_cgroup_move_task,
5164
	.early_init = 0,
K
KAMEZAWA Hiroyuki 已提交
5165
	.use_id = 1,
B
Balbir Singh 已提交
5166
};
5167 5168

#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
5169 5170 5171
static int __init enable_swap_account(char *s)
{
	/* consider enabled if no parameter or 1 is given */
5172
	if (!strcmp(s, "1"))
5173
		really_do_swap_account = 1;
5174
	else if (!strcmp(s, "0"))
5175 5176 5177
		really_do_swap_account = 0;
	return 1;
}
5178
__setup("swapaccount=", enable_swap_account);
5179 5180

#endif