memcontrol.c 130.0 KB
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/* memcontrol.c - Memory Controller
 *
 * Copyright IBM Corporation, 2007
 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
 *
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 * Copyright 2007 OpenVZ SWsoft Inc
 * Author: Pavel Emelianov <xemul@openvz.org>
 *
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 * Memory thresholds
 * Copyright (C) 2009 Nokia Corporation
 * Author: Kirill A. Shutemov
 *
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 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

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

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#include <trace/events/vmscan.h>

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

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#else
#define do_swap_account		(0)
#endif

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/*
 * Per memcg event counter is incremented at every pagein/pageout. This counter
 * is used for trigger some periodic events. This is straightforward and better
 * than using jiffies etc. to handle periodic memcg event.
 *
 * These values will be used as !((event) & ((1 <<(thresh)) - 1))
 */
#define THRESHOLDS_EVENTS_THRESH (7) /* once in 128 */
#define SOFTLIMIT_EVENTS_THRESH (10) /* once in 1024 */
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/*
 * Statistics for memory cgroup.
 */
enum mem_cgroup_stat_index {
	/*
	 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
	 */
	MEM_CGROUP_STAT_CACHE, 	   /* # of pages charged as cache */
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	MEM_CGROUP_STAT_RSS,	   /* # of pages charged as anon rss */
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	MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */
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	MEM_CGROUP_STAT_PGPGIN_COUNT,	/* # of pages paged in */
	MEM_CGROUP_STAT_PGPGOUT_COUNT,	/* # of pages paged out */
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	MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
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	MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */
	/* incremented at every  pagein/pageout */
	MEM_CGROUP_EVENTS = MEM_CGROUP_STAT_DATA,
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	MEM_CGROUP_ON_MOVE,	/* someone is moving account between groups */
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	MEM_CGROUP_STAT_NSTATS,
};

struct mem_cgroup_stat_cpu {
	s64 count[MEM_CGROUP_STAT_NSTATS];
};

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/*
 * per-zone information in memory controller.
 */
struct mem_cgroup_per_zone {
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	/*
	 * spin_lock to protect the per cgroup LRU
	 */
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	struct list_head	lists[NR_LRU_LISTS];
	unsigned long		count[NR_LRU_LISTS];
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	struct zone_reclaim_stat reclaim_stat;
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	struct rb_node		tree_node;	/* RB tree node */
	unsigned long long	usage_in_excess;/* Set to the value by which */
						/* the soft limit is exceeded*/
	bool			on_tree;
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	struct mem_cgroup	*mem;		/* Back pointer, we cannot */
						/* use container_of	   */
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};
/* Macro for accessing counter */
#define MEM_CGROUP_ZSTAT(mz, idx)	((mz)->count[(idx)])

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

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

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

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

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

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

static struct mem_cgroup_tree soft_limit_tree __read_mostly;

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

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

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

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	/*
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	 * While reclaiming in a hierarchy, we cache the last child we
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	 * reclaimed from.
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	 */
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	int last_scanned_child;
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	/*
	 * Should the accounting and control be hierarchical, per subtree?
	 */
	bool use_hierarchy;
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	atomic_t	oom_lock;
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	atomic_t	refcnt;
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	unsigned int	swappiness;
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	/* OOM-Killer disable */
	int		oom_kill_disable;
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	/* set when res.limit == memsw.limit */
	bool		memsw_is_minimum;

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

	/* thresholds for memory usage. RCU-protected */
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	struct mem_cgroup_thresholds thresholds;
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	/* thresholds for mem+swap usage. RCU-protected */
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	struct mem_cgroup_thresholds memsw_thresholds;
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	/* For oom notifier event fd */
	struct list_head oom_notify;

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	/*
	 * Should we move charges of a task when a task is moved into this
	 * mem_cgroup ? And what type of charges should we move ?
	 */
	unsigned long 	move_charge_at_immigrate;
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	/*
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	 * percpu counter.
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	 */
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	struct mem_cgroup_stat_cpu *stat;
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	/*
	 * used when a cpu is offlined or other synchronizations
	 * See mem_cgroup_read_stat().
	 */
	struct mem_cgroup_stat_cpu nocpu_base;
	spinlock_t pcp_counter_lock;
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};

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

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

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

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

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

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/* only for here (for easy reading.) */
#define PCGF_CACHE	(1UL << PCG_CACHE)
#define PCGF_USED	(1UL << PCG_USED)
#define PCGF_LOCK	(1UL << PCG_LOCK)
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/* Not used, but added here for completeness */
#define PCGF_ACCT	(1UL << PCG_ACCT)
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/* for encoding cft->private value on file */
#define _MEM			(0)
#define _MEMSWAP		(1)
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#define _OOM_TYPE		(2)
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#define MEMFILE_PRIVATE(x, val)	(((x) << 16) | (val))
#define MEMFILE_TYPE(val)	(((val) >> 16) & 0xffff)
#define MEMFILE_ATTR(val)	((val) & 0xffff)
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/* Used for OOM nofiier */
#define OOM_CONTROL		(0)
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/*
 * Reclaim flags for mem_cgroup_hierarchical_reclaim
 */
#define MEM_CGROUP_RECLAIM_NOSWAP_BIT	0x0
#define MEM_CGROUP_RECLAIM_NOSWAP	(1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
#define MEM_CGROUP_RECLAIM_SHRINK_BIT	0x1
#define MEM_CGROUP_RECLAIM_SHRINK	(1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
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#define MEM_CGROUP_RECLAIM_SOFT_BIT	0x2
#define MEM_CGROUP_RECLAIM_SOFT		(1 << MEM_CGROUP_RECLAIM_SOFT_BIT)
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static void mem_cgroup_get(struct mem_cgroup *mem);
static void mem_cgroup_put(struct mem_cgroup *mem);
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static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
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static void drain_all_stock_async(void);
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static struct mem_cgroup_per_zone *
mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
{
	return &mem->info.nodeinfo[nid]->zoneinfo[zid];
}

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

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

	if (!mem)
		return NULL;

	return mem_cgroup_zoneinfo(mem, nid, zid);
}

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

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

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

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

	if (mz->on_tree)
		return;

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

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

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


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

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

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

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

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

static struct mem_cgroup_per_zone *
__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
{
	struct rb_node *rightmost = NULL;
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	struct mem_cgroup_per_zone *mz;
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retry:
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	mz = NULL;
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	rightmost = rb_last(&mctz->rb_root);
	if (!rightmost)
		goto done;		/* Nothing to reclaim from */

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

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

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

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/*
 * Implementation Note: reading percpu statistics for memcg.
 *
 * Both of vmstat[] and percpu_counter has threshold and do periodic
 * synchronization to implement "quick" read. There are trade-off between
 * reading cost and precision of value. Then, we may have a chance to implement
 * a periodic synchronizion of counter in memcg's counter.
 *
 * But this _read() function is used for user interface now. The user accounts
 * memory usage by memory cgroup and he _always_ requires exact value because
 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
 * have to visit all online cpus and make sum. So, for now, unnecessary
 * synchronization is not implemented. (just implemented for cpu hotplug)
 *
 * If there are kernel internal actions which can make use of some not-exact
 * value, and reading all cpu value can be performance bottleneck in some
 * common workload, threashold and synchonization as vmstat[] should be
 * implemented.
 */
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static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
		enum mem_cgroup_stat_index idx)
{
	int cpu;
	s64 val = 0;

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

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

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

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

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

607 608
	if (file)
		__this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], nr_pages);
609
	else
610
		__this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], nr_pages);
611

612 613
	/* pagein of a big page is an event. So, ignore page size */
	if (nr_pages > 0)
614
		__this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGIN_COUNT]);
615
	else
616
		__this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGOUT_COUNT]);
617 618

	__this_cpu_add(mem->stat->count[MEM_CGROUP_EVENTS], nr_pages);
619

620
	preempt_enable();
621 622
}

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static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
624
					enum lru_list idx)
625 626 627 628 629 630 631 632 633 634 635
{
	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;
636 637
}

638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660
static bool __memcg_event_check(struct mem_cgroup *mem, int event_mask_shift)
{
	s64 val;

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

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

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

661
static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
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{
	return container_of(cgroup_subsys_state(cont,
				mem_cgroup_subsys_id), struct mem_cgroup,
				css);
}

668
struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
669
{
670 671 672 673 674 675 676 677
	/*
	 * 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;

678 679 680 681
	return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
				struct mem_cgroup, css);
}

682 683 684
static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
{
	struct mem_cgroup *mem = NULL;
685 686 687

	if (!mm)
		return NULL;
688 689 690 691 692 693 694 695 696 697 698 699 700 701 702
	/*
	 * Because we have no locks, mm->owner's may be being moved to other
	 * cgroup. We use css_tryget() here even if this looks
	 * pessimistic (rather than adding locks here).
	 */
	rcu_read_lock();
	do {
		mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
		if (unlikely(!mem))
			break;
	} while (!css_tryget(&mem->css));
	rcu_read_unlock();
	return mem;
}

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/* The caller has to guarantee "mem" exists before calling this */
static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *mem)
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{
706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727
	struct cgroup_subsys_state *css;
	int found;

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

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

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	hierarchy_used = iter->use_hierarchy;
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	css_put(&iter->css);
742 743
	/* If no ROOT, walk all, ignore hierarchy */
	if (!cond || (root && !hierarchy_used))
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		return NULL;
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746 747 748
	if (!root)
		root = root_mem_cgroup;

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

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

777 778 779
#define for_each_mem_cgroup_all(iter) \
	for_each_mem_cgroup_tree_cond(iter, NULL, true)

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781 782 783 784 785
static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
{
	return (mem == root_mem_cgroup);
}

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/*
 * Following LRU functions are allowed to be used without PCG_LOCK.
 * Operations are called by routine of global LRU independently from memcg.
 * What we have to take care of here is validness of pc->mem_cgroup.
 *
 * Changes to pc->mem_cgroup happens when
 * 1. charge
 * 2. moving account
 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
 * It is added to LRU before charge.
 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
 * When moving account, the page is not on LRU. It's isolated.
 */
799

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void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
{
	struct page_cgroup *pc;
	struct mem_cgroup_per_zone *mz;
804

805
	if (mem_cgroup_disabled())
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		return;
	pc = lookup_page_cgroup(page);
	/* can happen while we handle swapcache. */
809
	if (!TestClearPageCgroupAcctLRU(pc))
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		return;
811
	VM_BUG_ON(!pc->mem_cgroup);
812 813 814 815
	/*
	 * We don't check PCG_USED bit. It's cleared when the "page" is finally
	 * removed from global LRU.
	 */
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	mz = page_cgroup_zoneinfo(pc);
817 818
	/* huge page split is done under lru_lock. so, we have no races. */
	MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page);
819 820 821
	if (mem_cgroup_is_root(pc->mem_cgroup))
		return;
	VM_BUG_ON(list_empty(&pc->lru));
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	list_del_init(&pc->lru);
823 824
}

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void mem_cgroup_del_lru(struct page *page)
826
{
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	mem_cgroup_del_lru_list(page, page_lru(page));
}
829

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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;
834

835
	if (mem_cgroup_disabled())
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		return;
837

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	pc = lookup_page_cgroup(page);
839
	/* unused or root page is not rotated. */
840 841 842 843 844
	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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		return;
	mz = page_cgroup_zoneinfo(pc);
	list_move(&pc->lru, &mz->lists[lru]);
848 849
}

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void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
851
{
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	struct page_cgroup *pc;
	struct mem_cgroup_per_zone *mz;
854

855
	if (mem_cgroup_disabled())
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		return;
	pc = lookup_page_cgroup(page);
858
	VM_BUG_ON(PageCgroupAcctLRU(pc));
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	if (!PageCgroupUsed(pc))
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		return;
861 862
	/* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
	smp_rmb();
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	mz = page_cgroup_zoneinfo(pc);
864 865
	/* huge page split is done under lru_lock. so, we have no races. */
	MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page);
866 867 868
	SetPageCgroupAcctLRU(pc);
	if (mem_cgroup_is_root(pc->mem_cgroup))
		return;
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	list_add(&pc->lru, &mz->lists[lru]);
}
871

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/*
873 874 875 876 877
 * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to
 * lru because the page may.be reused after it's fully uncharged (because of
 * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge
 * it again. This function is only used to charge SwapCache. It's done under
 * lock_page and expected that zone->lru_lock is never held.
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 */
879
static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page)
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{
881 882 883 884 885 886 887 888 889 890 891 892
	unsigned long flags;
	struct zone *zone = page_zone(page);
	struct page_cgroup *pc = lookup_page_cgroup(page);

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

895 896 897 898 899 900 901 902
static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page)
{
	unsigned long flags;
	struct zone *zone = page_zone(page);
	struct page_cgroup *pc = lookup_page_cgroup(page);

	spin_lock_irqsave(&zone->lru_lock, flags);
	/* link when the page is linked to LRU but page_cgroup isn't */
903
	if (PageLRU(page) && !PageCgroupAcctLRU(pc))
904 905 906 907 908
		mem_cgroup_add_lru_list(page, page_lru(page));
	spin_unlock_irqrestore(&zone->lru_lock, flags);
}


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void mem_cgroup_move_lists(struct page *page,
			   enum lru_list from, enum lru_list to)
{
912
	if (mem_cgroup_disabled())
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913 914 915
		return;
	mem_cgroup_del_lru_list(page, from);
	mem_cgroup_add_lru_list(page, to);
916 917
}

918 919 920
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
{
	int ret;
921
	struct mem_cgroup *curr = NULL;
922
	struct task_struct *p;
923

924 925 926 927 928
	p = find_lock_task_mm(task);
	if (!p)
		return 0;
	curr = try_get_mem_cgroup_from_mm(p->mm);
	task_unlock(p);
929 930
	if (!curr)
		return 0;
931 932 933 934 935 936 937
	/*
	 * 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)
938 939 940 941
		ret = css_is_ancestor(&curr->css, &mem->css);
	else
		ret = (curr == mem);
	css_put(&curr->css);
942 943 944
	return ret;
}

945
static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
946 947 948
{
	unsigned long active;
	unsigned long inactive;
949 950
	unsigned long gb;
	unsigned long inactive_ratio;
951

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	inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON);
	active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON);
954

955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981
	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)
982 983 984 985 986
		return 1;

	return 0;
}

987 988 989 990 991 992 993 994 995 996 997
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);
}

998 999 1000 1001
unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
				       struct zone *zone,
				       enum lru_list lru)
{
1002
	int nid = zone_to_nid(zone);
1003 1004 1005 1006 1007 1008
	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)
{
1012
	int nid = zone_to_nid(zone);
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	int zid = zone_idx(zone);
	struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);

	return &mz->reclaim_stat;
}

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

	if (mem_cgroup_disabled())
		return NULL;

	pc = lookup_page_cgroup(page);
1029 1030
	if (!PageCgroupUsed(pc))
		return NULL;
1031 1032
	/* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
	smp_rmb();
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	mz = page_cgroup_zoneinfo(pc);
	if (!mz)
		return NULL;

	return &mz->reclaim_stat;
}

1040 1041 1042 1043 1044
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,
1045
					int active, int file)
1046 1047 1048 1049 1050 1051
{
	unsigned long nr_taken = 0;
	struct page *page;
	unsigned long scan;
	LIST_HEAD(pc_list);
	struct list_head *src;
1052
	struct page_cgroup *pc, *tmp;
1053
	int nid = zone_to_nid(z);
1054 1055
	int zid = zone_idx(z);
	struct mem_cgroup_per_zone *mz;
1056
	int lru = LRU_FILE * file + active;
1057
	int ret;
1058

1059
	BUG_ON(!mem_cont);
1060
	mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
1061
	src = &mz->lists[lru];
1062

1063 1064
	scan = 0;
	list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
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		if (scan >= nr_to_scan)
1066
			break;
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		page = pc->page;
1069 1070
		if (unlikely(!PageCgroupUsed(pc)))
			continue;
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1071
		if (unlikely(!PageLRU(page)))
1072 1073
			continue;

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		scan++;
1075 1076 1077
		ret = __isolate_lru_page(page, mode, file);
		switch (ret) {
		case 0:
1078
			list_move(&page->lru, dst);
1079
			mem_cgroup_del_lru(page);
1080
			nr_taken += hpage_nr_pages(page);
1081 1082 1083 1084 1085 1086 1087
			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;
1088 1089 1090 1091
		}
	}

	*scanned = scan;
1092 1093 1094 1095

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

1096 1097 1098
	return nr_taken;
}

1099 1100 1101
#define mem_cgroup_from_res_counter(counter, member)	\
	container_of(counter, struct mem_cgroup, member)

1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113
static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
{
	if (do_swap_account) {
		if (res_counter_check_under_limit(&mem->res) &&
			res_counter_check_under_limit(&mem->memsw))
			return true;
	} else
		if (res_counter_check_under_limit(&mem->res))
			return true;
	return false;
}

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

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

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

	return swappiness;
}

1130 1131 1132
static void mem_cgroup_start_move(struct mem_cgroup *mem)
{
	int cpu;
1133 1134 1135 1136

	get_online_cpus();
	spin_lock(&mem->pcp_counter_lock);
	for_each_online_cpu(cpu)
1137
		per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1;
1138 1139 1140
	mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1;
	spin_unlock(&mem->pcp_counter_lock);
	put_online_cpus();
1141 1142 1143 1144 1145 1146 1147 1148 1149 1150

	synchronize_rcu();
}

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

	if (!mem)
		return;
1151 1152 1153
	get_online_cpus();
	spin_lock(&mem->pcp_counter_lock);
	for_each_online_cpu(cpu)
1154
		per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1;
1155 1156 1157
	mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1;
	spin_unlock(&mem->pcp_counter_lock);
	put_online_cpus();
1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175
}
/*
 * 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;
}
1176 1177 1178

static bool mem_cgroup_under_move(struct mem_cgroup *mem)
{
1179 1180
	struct mem_cgroup *from;
	struct mem_cgroup *to;
1181
	bool ret = false;
1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196
	/*
	 * 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);
1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215
	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;
}

1216
/**
1217
 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235
 * @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;

1236
	if (!memcg || !p)
1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282
		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));
}

1283 1284 1285 1286 1287 1288 1289
/*
 * This function returns the number of memcg under hierarchy tree. Returns
 * 1(self count) if no children.
 */
static int mem_cgroup_count_children(struct mem_cgroup *mem)
{
	int num = 0;
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1290 1291 1292 1293
	struct mem_cgroup *iter;

	for_each_mem_cgroup_tree(iter, mem)
		num++;
1294 1295 1296
	return num;
}

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1297 1298 1299 1300 1301 1302 1303 1304
/*
 * Return the memory (and swap, if configured) limit for a memcg.
 */
u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
{
	u64 limit;
	u64 memsw;

1305 1306 1307
	limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
	limit += total_swap_pages << PAGE_SHIFT;

D
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1308 1309 1310 1311 1312 1313 1314 1315
	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);
}

1316
/*
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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 1351 1352 1353 1354 1355 1356 1357 1358
 * Visit the first child (need not be the first child as per the ordering
 * of the cgroup list, since we track last_scanned_child) of @mem and use
 * that to reclaim free pages from.
 */
static struct mem_cgroup *
mem_cgroup_select_victim(struct mem_cgroup *root_mem)
{
	struct mem_cgroup *ret = NULL;
	struct cgroup_subsys_state *css;
	int nextid, found;

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

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

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

	return ret;
}

/*
 * Scan the hierarchy if needed to reclaim memory. We remember the last child
 * we reclaimed from, so that we don't end up penalizing one child extensively
 * based on its position in the children list.
1359 1360
 *
 * root_mem is the original ancestor that we've been reclaim from.
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1361 1362 1363
 *
 * We give up and return to the caller when we visit root_mem twice.
 * (other groups can be removed while we're walking....)
1364 1365
 *
 * If shrink==true, for avoiding to free too much, this returns immedieately.
1366 1367
 */
static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
1368
						struct zone *zone,
1369 1370
						gfp_t gfp_mask,
						unsigned long reclaim_options)
1371
{
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1372 1373 1374
	struct mem_cgroup *victim;
	int ret, total = 0;
	int loop = 0;
1375 1376
	bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
	bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
1377 1378
	bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
	unsigned long excess = mem_cgroup_get_excess(root_mem);
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1379

1380 1381 1382 1383
	/* If memsw_is_minimum==1, swap-out is of-no-use. */
	if (root_mem->memsw_is_minimum)
		noswap = true;

1384
	while (1) {
K
KAMEZAWA Hiroyuki 已提交
1385
		victim = mem_cgroup_select_victim(root_mem);
1386
		if (victim == root_mem) {
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1387
			loop++;
1388 1389
			if (loop >= 1)
				drain_all_stock_async();
1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412
			if (loop >= 2) {
				/*
				 * If we have not been able to reclaim
				 * anything, it might because there are
				 * no reclaimable pages under this hierarchy
				 */
				if (!check_soft || !total) {
					css_put(&victim->css);
					break;
				}
				/*
				 * We want to do more targetted reclaim.
				 * excess >> 2 is not to excessive so as to
				 * reclaim too much, nor too less that we keep
				 * coming back to reclaim from this cgroup
				 */
				if (total >= (excess >> 2) ||
					(loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) {
					css_put(&victim->css);
					break;
				}
			}
		}
1413
		if (!mem_cgroup_local_usage(victim)) {
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KAMEZAWA Hiroyuki 已提交
1414 1415
			/* this cgroup's local usage == 0 */
			css_put(&victim->css);
1416 1417
			continue;
		}
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1418
		/* we use swappiness of local cgroup */
1419 1420
		if (check_soft)
			ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
1421
				noswap, get_swappiness(victim), zone);
1422 1423 1424
		else
			ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
						noswap, get_swappiness(victim));
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1425
		css_put(&victim->css);
1426 1427 1428 1429 1430 1431 1432
		/*
		 * 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;
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1433
		total += ret;
1434 1435 1436 1437
		if (check_soft) {
			if (res_counter_check_under_soft_limit(&root_mem->res))
				return total;
		} else if (mem_cgroup_check_under_limit(root_mem))
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1438
			return 1 + total;
1439
	}
K
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1440
	return total;
1441 1442
}

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1443 1444 1445 1446 1447 1448
/*
 * 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
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1449 1450
	int x, lock_count = 0;
	struct mem_cgroup *iter;
1451

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1452 1453 1454 1455
	for_each_mem_cgroup_tree(iter, mem) {
		x = atomic_inc_return(&iter->oom_lock);
		lock_count = max(x, lock_count);
	}
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1456 1457 1458 1459

	if (lock_count == 1)
		return true;
	return false;
1460
}
1461

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1462
static int mem_cgroup_oom_unlock(struct mem_cgroup *mem)
1463
{
K
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1464 1465
	struct mem_cgroup *iter;

K
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1466 1467 1468 1469 1470
	/*
	 * 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.
	 */
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1471 1472
	for_each_mem_cgroup_tree(iter, mem)
		atomic_add_unless(&iter->oom_lock, -1, 0);
1473 1474 1475
	return 0;
}

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1476 1477 1478 1479

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

K
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1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515
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);
}

1516 1517
static void memcg_oom_recover(struct mem_cgroup *mem)
{
1518
	if (mem && atomic_read(&mem->oom_lock))
1519 1520 1521
		memcg_wakeup_oom(mem);
}

K
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1522 1523 1524 1525
/*
 * 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)
1526
{
K
KAMEZAWA Hiroyuki 已提交
1527
	struct oom_wait_info owait;
1528
	bool locked, need_to_kill;
K
KAMEZAWA Hiroyuki 已提交
1529

K
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1530 1531 1532 1533 1534
	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);
1535
	need_to_kill = true;
K
KAMEZAWA Hiroyuki 已提交
1536 1537 1538 1539 1540 1541 1542 1543
	/* 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.
	 */
1544 1545 1546 1547
	prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
	if (!locked || mem->oom_kill_disable)
		need_to_kill = false;
	if (locked)
K
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1548
		mem_cgroup_oom_notify(mem);
K
KAMEZAWA Hiroyuki 已提交
1549 1550
	mutex_unlock(&memcg_oom_mutex);

1551 1552
	if (need_to_kill) {
		finish_wait(&memcg_oom_waitq, &owait.wait);
K
KAMEZAWA Hiroyuki 已提交
1553
		mem_cgroup_out_of_memory(mem, mask);
1554
	} else {
K
KAMEZAWA Hiroyuki 已提交
1555
		schedule();
K
KAMEZAWA Hiroyuki 已提交
1556
		finish_wait(&memcg_oom_waitq, &owait.wait);
K
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1557 1558 1559
	}
	mutex_lock(&memcg_oom_mutex);
	mem_cgroup_oom_unlock(mem);
K
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1560
	memcg_wakeup_oom(mem);
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1561 1562 1563 1564 1565 1566 1567
	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;
1568 1569
}

1570 1571 1572
/*
 * Currently used to update mapped file statistics, but the routine can be
 * generalized to update other statistics as well.
1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591
 *
 * 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.
1592
 */
1593

1594 1595
void mem_cgroup_update_page_stat(struct page *page,
				 enum mem_cgroup_page_stat_item idx, int val)
1596 1597
{
	struct mem_cgroup *mem;
1598 1599
	struct page_cgroup *pc = lookup_page_cgroup(page);
	bool need_unlock = false;
1600
	unsigned long uninitialized_var(flags);
1601 1602 1603 1604

	if (unlikely(!pc))
		return;

1605
	rcu_read_lock();
1606
	mem = pc->mem_cgroup;
1607 1608 1609
	if (unlikely(!mem || !PageCgroupUsed(pc)))
		goto out;
	/* pc->mem_cgroup is unstable ? */
1610
	if (unlikely(mem_cgroup_stealed(mem)) || PageTransHuge(page)) {
1611
		/* take a lock against to access pc->mem_cgroup */
1612
		move_lock_page_cgroup(pc, &flags);
1613 1614 1615 1616 1617
		need_unlock = true;
		mem = pc->mem_cgroup;
		if (!mem || !PageCgroupUsed(pc))
			goto out;
	}
1618 1619

	switch (idx) {
1620
	case MEMCG_NR_FILE_MAPPED:
1621 1622 1623
		if (val > 0)
			SetPageCgroupFileMapped(pc);
		else if (!page_mapped(page))
1624
			ClearPageCgroupFileMapped(pc);
1625
		idx = MEM_CGROUP_STAT_FILE_MAPPED;
1626 1627 1628
		break;
	default:
		BUG();
1629
	}
1630

1631 1632
	this_cpu_add(mem->stat->count[idx], val);

1633 1634
out:
	if (unlikely(need_unlock))
1635
		move_unlock_page_cgroup(pc, &flags);
1636 1637
	rcu_read_unlock();
	return;
1638
}
1639
EXPORT_SYMBOL(mem_cgroup_update_page_stat);
1640

1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701
/*
 * size of first charge trial. "32" comes from vmscan.c's magic value.
 * TODO: maybe necessary to use big numbers in big irons.
 */
#define CHARGE_SIZE	(32 * PAGE_SIZE)
struct memcg_stock_pcp {
	struct mem_cgroup *cached; /* this never be root cgroup */
	int charge;
	struct work_struct work;
};
static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
static atomic_t memcg_drain_count;

/*
 * Try to consume stocked charge on this cpu. If success, PAGE_SIZE is consumed
 * from local stock and true is returned. If the stock is 0 or charges from a
 * cgroup which is not current target, returns false. This stock will be
 * refilled.
 */
static bool consume_stock(struct mem_cgroup *mem)
{
	struct memcg_stock_pcp *stock;
	bool ret = true;

	stock = &get_cpu_var(memcg_stock);
	if (mem == stock->cached && stock->charge)
		stock->charge -= PAGE_SIZE;
	else /* need to call res_counter_charge */
		ret = false;
	put_cpu_var(memcg_stock);
	return ret;
}

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

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

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

/*
 * Cache charges(val) which is from res_counter, to local per_cpu area.
1702
 * This will be consumed by consume_stock() function, later.
1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753
 */
static void refill_stock(struct mem_cgroup *mem, int val)
{
	struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);

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

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

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

1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768
/*
 * This function drains percpu counter value from DEAD cpu and
 * move it to local cpu. Note that this function can be preempted.
 */
static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *mem, int cpu)
{
	int i;

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

		per_cpu(mem->stat->count[i], cpu) = 0;
		mem->nocpu_base.count[i] += x;
	}
1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779
	/* 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];
1780 1781 1782 1783
	spin_unlock(&mem->pcp_counter_lock);
}

static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
1784 1785 1786 1787 1788
					unsigned long action,
					void *hcpu)
{
	int cpu = (unsigned long)hcpu;
	struct memcg_stock_pcp *stock;
1789
	struct mem_cgroup *iter;
1790

1791 1792 1793 1794 1795 1796
	if ((action == CPU_ONLINE)) {
		for_each_mem_cgroup_all(iter)
			synchronize_mem_cgroup_on_move(iter, cpu);
		return NOTIFY_OK;
	}

1797
	if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN)
1798
		return NOTIFY_OK;
1799 1800 1801 1802

	for_each_mem_cgroup_all(iter)
		mem_cgroup_drain_pcp_counter(iter, cpu);

1803 1804 1805 1806 1807
	stock = &per_cpu(memcg_stock, cpu);
	drain_stock(stock);
	return NOTIFY_OK;
}

1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834

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

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

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

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

1835
		res_counter_uncharge(&mem->res, csize);
1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875
		mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
		flags |= MEM_CGROUP_RECLAIM_NOSWAP;
	} else
		mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);

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

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

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

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

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

	return CHARGE_RETRY;
}

1876 1877 1878
/*
 * Unlike exported interface, "oom" parameter is added. if oom==true,
 * oom-killer can be invoked.
1879
 */
1880
static int __mem_cgroup_try_charge(struct mm_struct *mm,
A
Andrea Arcangeli 已提交
1881 1882 1883
				   gfp_t gfp_mask,
				   struct mem_cgroup **memcg, bool oom,
				   int page_size)
1884
{
1885 1886 1887
	int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
	struct mem_cgroup *mem = NULL;
	int ret;
A
Andrea Arcangeli 已提交
1888
	int csize = max(CHARGE_SIZE, (unsigned long) page_size);
1889

K
KAMEZAWA Hiroyuki 已提交
1890 1891 1892 1893 1894 1895 1896 1897
	/*
	 * 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;
1898

1899
	/*
1900 1901
	 * We always charge the cgroup the mm_struct belongs to.
	 * The mm_struct's mem_cgroup changes on task migration if the
1902 1903 1904
	 * 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
1905 1906 1907 1908
	if (!*memcg && !mm)
		goto bypass;
again:
	if (*memcg) { /* css should be a valid one */
1909
		mem = *memcg;
K
KAMEZAWA Hiroyuki 已提交
1910 1911 1912
		VM_BUG_ON(css_is_removed(&mem->css));
		if (mem_cgroup_is_root(mem))
			goto done;
A
Andrea Arcangeli 已提交
1913
		if (page_size == PAGE_SIZE && consume_stock(mem))
K
KAMEZAWA Hiroyuki 已提交
1914
			goto done;
1915 1916
		css_get(&mem->css);
	} else {
K
KAMEZAWA Hiroyuki 已提交
1917
		struct task_struct *p;
1918

K
KAMEZAWA Hiroyuki 已提交
1919 1920 1921
		rcu_read_lock();
		p = rcu_dereference(mm->owner);
		/*
1922 1923 1924 1925 1926 1927 1928 1929
		 * 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
1930 1931
		 */
		mem = mem_cgroup_from_task(p);
1932
		if (!mem || mem_cgroup_is_root(mem)) {
K
KAMEZAWA Hiroyuki 已提交
1933 1934 1935
			rcu_read_unlock();
			goto done;
		}
A
Andrea Arcangeli 已提交
1936
		if (page_size == PAGE_SIZE && consume_stock(mem)) {
K
KAMEZAWA Hiroyuki 已提交
1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954
			/*
			 * 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();
	}
1955

1956 1957
	do {
		bool oom_check;
1958

1959
		/* If killed, bypass charge */
K
KAMEZAWA Hiroyuki 已提交
1960 1961
		if (fatal_signal_pending(current)) {
			css_put(&mem->css);
1962
			goto bypass;
K
KAMEZAWA Hiroyuki 已提交
1963
		}
1964

1965 1966 1967 1968
		oom_check = false;
		if (oom && !nr_oom_retries) {
			oom_check = true;
			nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
1969
		}
1970

1971
		ret = __mem_cgroup_do_charge(mem, gfp_mask, csize, oom_check);
1972

1973 1974 1975 1976
		switch (ret) {
		case CHARGE_OK:
			break;
		case CHARGE_RETRY: /* not in OOM situation but retry */
A
Andrea Arcangeli 已提交
1977
			csize = page_size;
K
KAMEZAWA Hiroyuki 已提交
1978 1979 1980
			css_put(&mem->css);
			mem = NULL;
			goto again;
1981
		case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
K
KAMEZAWA Hiroyuki 已提交
1982
			css_put(&mem->css);
1983 1984
			goto nomem;
		case CHARGE_NOMEM: /* OOM routine works */
K
KAMEZAWA Hiroyuki 已提交
1985 1986
			if (!oom) {
				css_put(&mem->css);
K
KAMEZAWA Hiroyuki 已提交
1987
				goto nomem;
K
KAMEZAWA Hiroyuki 已提交
1988
			}
1989 1990 1991 1992
			/* If oom, we never return -ENOMEM */
			nr_oom_retries--;
			break;
		case CHARGE_OOM_DIE: /* Killed by OOM Killer */
K
KAMEZAWA Hiroyuki 已提交
1993
			css_put(&mem->css);
K
KAMEZAWA Hiroyuki 已提交
1994
			goto bypass;
1995
		}
1996 1997
	} while (ret != CHARGE_OK);

A
Andrea Arcangeli 已提交
1998 1999
	if (csize > page_size)
		refill_stock(mem, csize - page_size);
K
KAMEZAWA Hiroyuki 已提交
2000
	css_put(&mem->css);
2001
done:
K
KAMEZAWA Hiroyuki 已提交
2002
	*memcg = mem;
2003 2004
	return 0;
nomem:
K
KAMEZAWA Hiroyuki 已提交
2005
	*memcg = NULL;
2006
	return -ENOMEM;
K
KAMEZAWA Hiroyuki 已提交
2007 2008 2009
bypass:
	*memcg = NULL;
	return 0;
2010
}
2011

2012 2013 2014 2015 2016
/*
 * 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().
 */
2017 2018
static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem,
							unsigned long count)
2019 2020
{
	if (!mem_cgroup_is_root(mem)) {
2021
		res_counter_uncharge(&mem->res, PAGE_SIZE * count);
2022
		if (do_swap_account)
2023
			res_counter_uncharge(&mem->memsw, PAGE_SIZE * count);
2024
	}
2025 2026
}

A
Andrea Arcangeli 已提交
2027 2028
static void mem_cgroup_cancel_charge(struct mem_cgroup *mem,
				     int page_size)
2029
{
A
Andrea Arcangeli 已提交
2030
	__mem_cgroup_cancel_charge(mem, page_size >> PAGE_SHIFT);
2031 2032
}

2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051
/*
 * 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);
}

2052
struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2053
{
2054
	struct mem_cgroup *mem = NULL;
2055
	struct page_cgroup *pc;
2056
	unsigned short id;
2057 2058
	swp_entry_t ent;

2059 2060 2061
	VM_BUG_ON(!PageLocked(page));

	pc = lookup_page_cgroup(page);
2062
	lock_page_cgroup(pc);
2063
	if (PageCgroupUsed(pc)) {
2064
		mem = pc->mem_cgroup;
2065 2066
		if (mem && !css_tryget(&mem->css))
			mem = NULL;
2067
	} else if (PageSwapCache(page)) {
2068
		ent.val = page_private(page);
2069 2070 2071 2072 2073 2074
		id = lookup_swap_cgroup(ent);
		rcu_read_lock();
		mem = mem_cgroup_lookup(id);
		if (mem && !css_tryget(&mem->css))
			mem = NULL;
		rcu_read_unlock();
2075
	}
2076
	unlock_page_cgroup(pc);
2077 2078 2079
	return mem;
}

2080 2081 2082 2083
static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
				       struct page_cgroup *pc,
				       enum charge_type ctype,
				       int page_size)
2084
{
2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100
	int nr_pages = page_size >> PAGE_SHIFT;

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

	lock_page_cgroup(pc);
	if (unlikely(PageCgroupUsed(pc))) {
		unlock_page_cgroup(pc);
		mem_cgroup_cancel_charge(mem, page_size);
		return;
	}
	/*
	 * we don't need page_cgroup_lock about tail pages, becase they are not
	 * accessed by any other context at this point.
	 */
2101
	pc->mem_cgroup = mem;
2102 2103 2104 2105 2106 2107 2108
	/*
	 * We access a page_cgroup asynchronously without lock_page_cgroup().
	 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
	 * is accessed after testing USED bit. To make pc->mem_cgroup visible
	 * before USED bit, we need memory barrier here.
	 * See mem_cgroup_add_lru_list(), etc.
 	 */
K
KAMEZAWA Hiroyuki 已提交
2109
	smp_wmb();
2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122
	switch (ctype) {
	case MEM_CGROUP_CHARGE_TYPE_CACHE:
	case MEM_CGROUP_CHARGE_TYPE_SHMEM:
		SetPageCgroupCache(pc);
		SetPageCgroupUsed(pc);
		break;
	case MEM_CGROUP_CHARGE_TYPE_MAPPED:
		ClearPageCgroupCache(pc);
		SetPageCgroupUsed(pc);
		break;
	default:
		break;
	}
2123

2124
	mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), nr_pages);
2125
	unlock_page_cgroup(pc);
2126 2127 2128 2129 2130
	/*
	 * "charge_statistics" updated event counter. Then, check it.
	 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
	 * if they exceeds softlimit.
	 */
2131
	memcg_check_events(mem, pc->page);
2132
}
2133

2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147
#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;

2148 2149
	if (mem_cgroup_disabled())
		return;
2150
	/*
2151
	 * We have no races with charge/uncharge but will have races with
2152 2153 2154 2155 2156 2157
	 * page state accounting.
	 */
	move_lock_page_cgroup(head_pc, &flags);

	tail_pc->mem_cgroup = head_pc->mem_cgroup;
	smp_wmb(); /* see __commit_charge() */
2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170
	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);
		mz = page_cgroup_zoneinfo(head_pc);
		MEM_CGROUP_ZSTAT(mz, lru) -= 1;
	}
2171 2172 2173 2174 2175
	tail_pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
	move_unlock_page_cgroup(head_pc, &flags);
}
#endif

2176
/**
2177
 * __mem_cgroup_move_account - move account of the page
2178 2179 2180
 * @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.
2181
 * @uncharge: whether we should call uncharge and css_put against @from.
2182 2183
 *
 * The caller must confirm following.
K
KAMEZAWA Hiroyuki 已提交
2184
 * - page is not on LRU (isolate_page() is useful.)
2185
 * - the pc is locked, used, and ->mem_cgroup points to @from.
2186
 *
2187 2188 2189 2190
 * This function doesn't do "charge" nor css_get to new cgroup. It should be
 * done by a caller(__mem_cgroup_try_charge would be usefull). If @uncharge is
 * true, this function does "uncharge" from old cgroup, but it doesn't if
 * @uncharge is false, so a caller should do "uncharge".
2191 2192
 */

2193
static void __mem_cgroup_move_account(struct page_cgroup *pc,
2194 2195
	struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge,
	int charge_size)
2196
{
2197 2198
	int nr_pages = charge_size >> PAGE_SHIFT;

2199
	VM_BUG_ON(from == to);
K
KAMEZAWA Hiroyuki 已提交
2200
	VM_BUG_ON(PageLRU(pc->page));
2201
	VM_BUG_ON(!page_is_cgroup_locked(pc));
2202 2203
	VM_BUG_ON(!PageCgroupUsed(pc));
	VM_BUG_ON(pc->mem_cgroup != from);
2204

2205
	if (PageCgroupFileMapped(pc)) {
2206 2207 2208 2209 2210
		/* 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();
2211
	}
2212
	mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages);
2213 2214
	if (uncharge)
		/* This is not "cancel", but cancel_charge does all we need. */
2215
		mem_cgroup_cancel_charge(from, charge_size);
2216

2217
	/* caller should have done css_get */
K
KAMEZAWA Hiroyuki 已提交
2218
	pc->mem_cgroup = to;
2219
	mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages);
2220 2221 2222
	/*
	 * We charges against "to" which may not have any tasks. Then, "to"
	 * can be under rmdir(). But in current implementation, caller of
2223 2224 2225
	 * this function is just force_empty() and move charge, so it's
	 * garanteed that "to" is never removed. So, we don't check rmdir
	 * status here.
2226
	 */
2227 2228 2229 2230 2231 2232 2233
}

/*
 * check whether the @pc is valid for moving account and call
 * __mem_cgroup_move_account()
 */
static int mem_cgroup_move_account(struct page_cgroup *pc,
2234 2235
		struct mem_cgroup *from, struct mem_cgroup *to,
		bool uncharge, int charge_size)
2236 2237
{
	int ret = -EINVAL;
2238
	unsigned long flags;
2239 2240 2241 2242 2243 2244
	/*
	 * 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.
	 */
2245 2246 2247
	if ((charge_size > PAGE_SIZE) && !PageTransHuge(pc->page))
		return -EBUSY;

2248 2249
	lock_page_cgroup(pc);
	if (PageCgroupUsed(pc) && pc->mem_cgroup == from) {
2250
		move_lock_page_cgroup(pc, &flags);
2251
		__mem_cgroup_move_account(pc, from, to, uncharge, charge_size);
2252
		move_unlock_page_cgroup(pc, &flags);
2253 2254 2255
		ret = 0;
	}
	unlock_page_cgroup(pc);
2256 2257 2258 2259 2260
	/*
	 * check events
	 */
	memcg_check_events(to, pc->page);
	memcg_check_events(from, pc->page);
2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271
	return ret;
}

/*
 * move charges to its parent.
 */

static int mem_cgroup_move_parent(struct page_cgroup *pc,
				  struct mem_cgroup *child,
				  gfp_t gfp_mask)
{
K
KAMEZAWA Hiroyuki 已提交
2272
	struct page *page = pc->page;
2273 2274 2275
	struct cgroup *cg = child->css.cgroup;
	struct cgroup *pcg = cg->parent;
	struct mem_cgroup *parent;
2276
	int page_size = PAGE_SIZE;
2277
	unsigned long flags;
2278 2279 2280 2281 2282 2283
	int ret;

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

2284 2285 2286 2287 2288
	ret = -EBUSY;
	if (!get_page_unless_zero(page))
		goto out;
	if (isolate_lru_page(page))
		goto put;
2289 2290 2291

	if (PageTransHuge(page))
		page_size = HPAGE_SIZE;
K
KAMEZAWA Hiroyuki 已提交
2292

2293
	parent = mem_cgroup_from_cont(pcg);
2294 2295
	ret = __mem_cgroup_try_charge(NULL, gfp_mask,
				&parent, false, page_size);
2296
	if (ret || !parent)
2297
		goto put_back;
2298

2299
	if (page_size > PAGE_SIZE)
2300 2301
		flags = compound_lock_irqsave(page);

2302
	ret = mem_cgroup_move_account(pc, child, parent, true, page_size);
2303
	if (ret)
2304
		mem_cgroup_cancel_charge(parent, page_size);
2305

2306
	if (page_size > PAGE_SIZE)
2307
		compound_unlock_irqrestore(page, flags);
2308
put_back:
K
KAMEZAWA Hiroyuki 已提交
2309
	putback_lru_page(page);
2310
put:
2311
	put_page(page);
2312
out:
2313 2314 2315
	return ret;
}

2316 2317 2318 2319 2320 2321 2322
/*
 * 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,
2323
				gfp_t gfp_mask, enum charge_type ctype)
2324
{
2325
	struct mem_cgroup *mem = NULL;
2326 2327
	struct page_cgroup *pc;
	int ret;
A
Andrea Arcangeli 已提交
2328 2329
	int page_size = PAGE_SIZE;

A
Andrea Arcangeli 已提交
2330
	if (PageTransHuge(page)) {
A
Andrea Arcangeli 已提交
2331
		page_size <<= compound_order(page);
A
Andrea Arcangeli 已提交
2332 2333
		VM_BUG_ON(!PageTransHuge(page));
	}
2334 2335 2336 2337 2338 2339 2340

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

A
Andrea Arcangeli 已提交
2341
	ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true, page_size);
2342
	if (ret || !mem)
2343 2344
		return ret;

A
Andrea Arcangeli 已提交
2345
	__mem_cgroup_commit_charge(mem, pc, ctype, page_size);
2346 2347 2348
	return 0;
}

2349 2350
int mem_cgroup_newpage_charge(struct page *page,
			      struct mm_struct *mm, gfp_t gfp_mask)
2351
{
2352
	if (mem_cgroup_disabled())
2353
		return 0;
2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364
	/*
	 * 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;
2365
	return mem_cgroup_charge_common(page, mm, gfp_mask,
2366
				MEM_CGROUP_CHARGE_TYPE_MAPPED);
2367 2368
}

D
Daisuke Nishimura 已提交
2369 2370 2371 2372
static void
__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
					enum charge_type ctype);

2373 2374
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
				gfp_t gfp_mask)
2375
{
2376 2377
	int ret;

2378
	if (mem_cgroup_disabled())
2379
		return 0;
2380 2381
	if (PageCompound(page))
		return 0;
2382 2383 2384 2385 2386 2387 2388 2389
	/*
	 * 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.)
2390 2391
	 * And when the page is SwapCache, it should take swap information
	 * into account. This is under lock_page() now.
2392 2393 2394 2395
	 */
	if (!(gfp_mask & __GFP_WAIT)) {
		struct page_cgroup *pc;

2396 2397 2398 2399 2400 2401
		pc = lookup_page_cgroup(page);
		if (!pc)
			return 0;
		lock_page_cgroup(pc);
		if (PageCgroupUsed(pc)) {
			unlock_page_cgroup(pc);
2402 2403
			return 0;
		}
2404
		unlock_page_cgroup(pc);
2405 2406
	}

2407
	if (unlikely(!mm))
2408
		mm = &init_mm;
2409

2410 2411
	if (page_is_file_cache(page))
		return mem_cgroup_charge_common(page, mm, gfp_mask,
2412
				MEM_CGROUP_CHARGE_TYPE_CACHE);
2413

D
Daisuke Nishimura 已提交
2414 2415
	/* shmem */
	if (PageSwapCache(page)) {
2416 2417
		struct mem_cgroup *mem = NULL;

D
Daisuke Nishimura 已提交
2418 2419 2420 2421 2422 2423
		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,
2424
					MEM_CGROUP_CHARGE_TYPE_SHMEM);
2425 2426

	return ret;
2427 2428
}

2429 2430 2431
/*
 * While swap-in, try_charge -> commit or cancel, the page is locked.
 * And when try_charge() successfully returns, one refcnt to memcg without
2432
 * struct page_cgroup is acquired. This refcnt will be consumed by
2433 2434
 * "commit()" or removed by "cancel()"
 */
2435 2436 2437 2438 2439
int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
				 struct page *page,
				 gfp_t mask, struct mem_cgroup **ptr)
{
	struct mem_cgroup *mem;
2440
	int ret;
2441

2442
	if (mem_cgroup_disabled())
2443 2444 2445 2446 2447 2448
		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
2449 2450 2451
	 * 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.
2452 2453
	 */
	if (!PageSwapCache(page))
H
Hugh Dickins 已提交
2454
		goto charge_cur_mm;
2455
	mem = try_get_mem_cgroup_from_page(page);
2456 2457
	if (!mem)
		goto charge_cur_mm;
2458
	*ptr = mem;
A
Andrea Arcangeli 已提交
2459
	ret = __mem_cgroup_try_charge(NULL, mask, ptr, true, PAGE_SIZE);
2460 2461
	css_put(&mem->css);
	return ret;
2462 2463 2464
charge_cur_mm:
	if (unlikely(!mm))
		mm = &init_mm;
A
Andrea Arcangeli 已提交
2465
	return __mem_cgroup_try_charge(mm, mask, ptr, true, PAGE_SIZE);
2466 2467
}

D
Daisuke Nishimura 已提交
2468 2469 2470
static void
__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
					enum charge_type ctype)
2471 2472 2473
{
	struct page_cgroup *pc;

2474
	if (mem_cgroup_disabled())
2475 2476 2477
		return;
	if (!ptr)
		return;
2478
	cgroup_exclude_rmdir(&ptr->css);
2479
	pc = lookup_page_cgroup(page);
2480
	mem_cgroup_lru_del_before_commit_swapcache(page);
A
Andrea Arcangeli 已提交
2481
	__mem_cgroup_commit_charge(ptr, pc, ctype, PAGE_SIZE);
2482
	mem_cgroup_lru_add_after_commit_swapcache(page);
2483 2484 2485
	/*
	 * Now swap is on-memory. This means this page may be
	 * counted both as mem and swap....double count.
2486 2487 2488
	 * 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.
2489
	 */
2490
	if (do_swap_account && PageSwapCache(page)) {
2491
		swp_entry_t ent = {.val = page_private(page)};
2492
		unsigned short id;
2493
		struct mem_cgroup *memcg;
2494 2495 2496 2497

		id = swap_cgroup_record(ent, 0);
		rcu_read_lock();
		memcg = mem_cgroup_lookup(id);
2498
		if (memcg) {
2499 2500 2501 2502
			/*
			 * This recorded memcg can be obsolete one. So, avoid
			 * calling css_tryget
			 */
2503
			if (!mem_cgroup_is_root(memcg))
2504
				res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2505
			mem_cgroup_swap_statistics(memcg, false);
2506 2507
			mem_cgroup_put(memcg);
		}
2508
		rcu_read_unlock();
2509
	}
2510 2511 2512 2513 2514 2515
	/*
	 * 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);
2516 2517
}

D
Daisuke Nishimura 已提交
2518 2519 2520 2521 2522 2523
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);
}

2524 2525
void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
{
2526
	if (mem_cgroup_disabled())
2527 2528 2529
		return;
	if (!mem)
		return;
A
Andrea Arcangeli 已提交
2530
	mem_cgroup_cancel_charge(mem, PAGE_SIZE);
2531 2532
}

2533
static void
A
Andrea Arcangeli 已提交
2534 2535
__do_uncharge(struct mem_cgroup *mem, const enum charge_type ctype,
	      int page_size)
2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550
{
	struct memcg_batch_info *batch = NULL;
	bool uncharge_memsw = true;
	/* If swapout, usage of swap doesn't decrease */
	if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
		uncharge_memsw = false;

	batch = &current->memcg_batch;
	/*
	 * In usual, we do css_get() when we remember memcg pointer.
	 * But in this case, we keep res->usage until end of a series of
	 * uncharges. Then, it's ok to ignore memcg's refcnt.
	 */
	if (!batch->memcg)
		batch->memcg = mem;
2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561
	/*
	 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
	 * In those cases, all pages freed continously can be expected to be in
	 * the same cgroup and we have chance to coalesce uncharges.
	 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
	 * because we want to do uncharge as soon as possible.
	 */

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

A
Andrea Arcangeli 已提交
2562 2563 2564
	if (page_size != PAGE_SIZE)
		goto direct_uncharge;

2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577
	/*
	 * In typical case, batch->memcg == mem. This means we can
	 * merge a series of uncharges to an uncharge of res_counter.
	 * If not, we uncharge res_counter ony by one.
	 */
	if (batch->memcg != mem)
		goto direct_uncharge;
	/* remember freed charge and uncharge it later */
	batch->bytes += PAGE_SIZE;
	if (uncharge_memsw)
		batch->memsw_bytes += PAGE_SIZE;
	return;
direct_uncharge:
A
Andrea Arcangeli 已提交
2578
	res_counter_uncharge(&mem->res, page_size);
2579
	if (uncharge_memsw)
A
Andrea Arcangeli 已提交
2580
		res_counter_uncharge(&mem->memsw, page_size);
2581 2582
	if (unlikely(batch->memcg != mem))
		memcg_oom_recover(mem);
2583 2584
	return;
}
2585

2586
/*
2587
 * uncharge if !page_mapped(page)
2588
 */
2589
static struct mem_cgroup *
2590
__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
2591
{
2592
	int count;
H
Hugh Dickins 已提交
2593
	struct page_cgroup *pc;
2594
	struct mem_cgroup *mem = NULL;
A
Andrea Arcangeli 已提交
2595
	int page_size = PAGE_SIZE;
2596

2597
	if (mem_cgroup_disabled())
2598
		return NULL;
2599

K
KAMEZAWA Hiroyuki 已提交
2600
	if (PageSwapCache(page))
2601
		return NULL;
K
KAMEZAWA Hiroyuki 已提交
2602

A
Andrea Arcangeli 已提交
2603
	if (PageTransHuge(page)) {
A
Andrea Arcangeli 已提交
2604
		page_size <<= compound_order(page);
A
Andrea Arcangeli 已提交
2605 2606
		VM_BUG_ON(!PageTransHuge(page));
	}
A
Andrea Arcangeli 已提交
2607

2608
	count = page_size >> PAGE_SHIFT;
2609
	/*
2610
	 * Check if our page_cgroup is valid
2611
	 */
2612 2613
	pc = lookup_page_cgroup(page);
	if (unlikely(!pc || !PageCgroupUsed(pc)))
2614
		return NULL;
2615

2616
	lock_page_cgroup(pc);
K
KAMEZAWA Hiroyuki 已提交
2617

2618 2619
	mem = pc->mem_cgroup;

K
KAMEZAWA Hiroyuki 已提交
2620 2621 2622 2623 2624
	if (!PageCgroupUsed(pc))
		goto unlock_out;

	switch (ctype) {
	case MEM_CGROUP_CHARGE_TYPE_MAPPED:
K
KAMEZAWA Hiroyuki 已提交
2625
	case MEM_CGROUP_CHARGE_TYPE_DROP:
2626 2627
		/* See mem_cgroup_prepare_migration() */
		if (page_mapped(page) || PageCgroupMigration(pc))
K
KAMEZAWA Hiroyuki 已提交
2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638
			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;
2639
	}
K
KAMEZAWA Hiroyuki 已提交
2640

2641
	mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), -count);
K
KAMEZAWA Hiroyuki 已提交
2642

2643
	ClearPageCgroupUsed(pc);
2644 2645 2646 2647 2648 2649
	/*
	 * 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.
	 */
2650

2651
	unlock_page_cgroup(pc);
K
KAMEZAWA Hiroyuki 已提交
2652 2653 2654 2655
	/*
	 * even after unlock, we have mem->res.usage here and this memcg
	 * will never be freed.
	 */
2656
	memcg_check_events(mem, page);
K
KAMEZAWA Hiroyuki 已提交
2657 2658 2659 2660 2661
	if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
		mem_cgroup_swap_statistics(mem, true);
		mem_cgroup_get(mem);
	}
	if (!mem_cgroup_is_root(mem))
A
Andrea Arcangeli 已提交
2662
		__do_uncharge(mem, ctype, page_size);
2663

2664
	return mem;
K
KAMEZAWA Hiroyuki 已提交
2665 2666 2667

unlock_out:
	unlock_page_cgroup(pc);
2668
	return NULL;
2669 2670
}

2671 2672
void mem_cgroup_uncharge_page(struct page *page)
{
2673 2674 2675 2676 2677
	/* early check. */
	if (page_mapped(page))
		return;
	if (page->mapping && !PageAnon(page))
		return;
2678 2679 2680 2681 2682 2683
	__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));
2684
	VM_BUG_ON(page->mapping);
2685 2686 2687
	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
}

2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727
/*
 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
 * In that cases, pages are freed continuously and we can expect pages
 * are in the same memcg. All these calls itself limits the number of
 * pages freed at once, then uncharge_start/end() is called properly.
 * This may be called prural(2) times in a context,
 */

void mem_cgroup_uncharge_start(void)
{
	current->memcg_batch.do_batch++;
	/* We can do nest. */
	if (current->memcg_batch.do_batch == 1) {
		current->memcg_batch.memcg = NULL;
		current->memcg_batch.bytes = 0;
		current->memcg_batch.memsw_bytes = 0;
	}
}

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

	if (!batch->do_batch)
		return;

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

	if (!batch->memcg)
		return;
	/*
	 * This "batch->memcg" is valid without any css_get/put etc...
	 * bacause we hide charges behind us.
	 */
	if (batch->bytes)
		res_counter_uncharge(&batch->memcg->res, batch->bytes);
	if (batch->memsw_bytes)
		res_counter_uncharge(&batch->memcg->memsw, batch->memsw_bytes);
2728
	memcg_oom_recover(batch->memcg);
2729 2730 2731 2732
	/* forget this pointer (for sanity check) */
	batch->memcg = NULL;
}

2733
#ifdef CONFIG_SWAP
2734
/*
2735
 * called after __delete_from_swap_cache() and drop "page" account.
2736 2737
 * memcg information is recorded to swap_cgroup of "ent"
 */
K
KAMEZAWA Hiroyuki 已提交
2738 2739
void
mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
2740 2741
{
	struct mem_cgroup *memcg;
K
KAMEZAWA Hiroyuki 已提交
2742 2743 2744 2745 2746 2747
	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);
2748

K
KAMEZAWA Hiroyuki 已提交
2749 2750 2751 2752 2753
	/*
	 * record memcg information,  if swapout && memcg != NULL,
	 * mem_cgroup_get() was called in uncharge().
	 */
	if (do_swap_account && swapout && memcg)
2754
		swap_cgroup_record(ent, css_id(&memcg->css));
2755
}
2756
#endif
2757 2758 2759 2760 2761 2762 2763

#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
2764
{
2765
	struct mem_cgroup *memcg;
2766
	unsigned short id;
2767 2768 2769 2770

	if (!do_swap_account)
		return;

2771 2772 2773
	id = swap_cgroup_record(ent, 0);
	rcu_read_lock();
	memcg = mem_cgroup_lookup(id);
2774
	if (memcg) {
2775 2776 2777 2778
		/*
		 * We uncharge this because swap is freed.
		 * This memcg can be obsolete one. We avoid calling css_tryget
		 */
2779
		if (!mem_cgroup_is_root(memcg))
2780
			res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2781
		mem_cgroup_swap_statistics(memcg, false);
2782 2783
		mem_cgroup_put(memcg);
	}
2784
	rcu_read_unlock();
K
KAMEZAWA Hiroyuki 已提交
2785
}
2786 2787 2788 2789 2790 2791

/**
 * 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
2792
 * @need_fixup: whether we should fixup res_counters and refcounts.
2793 2794 2795 2796 2797 2798 2799 2800 2801 2802
 *
 * 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,
2803
		struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2804 2805 2806 2807 2808 2809 2810 2811
{
	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);
2812
		mem_cgroup_swap_statistics(to, true);
2813
		/*
2814 2815 2816 2817 2818 2819
		 * 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.
2820 2821
		 */
		mem_cgroup_get(to);
2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832
		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);
		}
2833 2834 2835 2836 2837 2838
		return 0;
	}
	return -EINVAL;
}
#else
static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
2839
		struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2840 2841 2842
{
	return -EINVAL;
}
2843
#endif
K
KAMEZAWA Hiroyuki 已提交
2844

2845
/*
2846 2847
 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
 * page belongs to.
2848
 */
2849 2850
int mem_cgroup_prepare_migration(struct page *page,
	struct page *newpage, struct mem_cgroup **ptr)
2851 2852
{
	struct page_cgroup *pc;
2853
	struct mem_cgroup *mem = NULL;
2854
	enum charge_type ctype;
2855
	int ret = 0;
2856

A
Andrea Arcangeli 已提交
2857
	VM_BUG_ON(PageTransHuge(page));
2858
	if (mem_cgroup_disabled())
2859 2860
		return 0;

2861 2862 2863
	pc = lookup_page_cgroup(page);
	lock_page_cgroup(pc);
	if (PageCgroupUsed(pc)) {
2864 2865
		mem = pc->mem_cgroup;
		css_get(&mem->css);
2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896
		/*
		 * 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);
2897
	}
2898
	unlock_page_cgroup(pc);
2899 2900 2901 2902 2903 2904
	/*
	 * If the page is not charged at this point,
	 * we return here.
	 */
	if (!mem)
		return 0;
2905

A
Andrea Arcangeli 已提交
2906
	*ptr = mem;
A
Andrea Arcangeli 已提交
2907
	ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, ptr, false, PAGE_SIZE);
2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919
	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;
2920
	}
2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933
	/*
	 * We charge new page before it's used/mapped. So, even if unlock_page()
	 * is called before end_migration, we can catch all events on this new
	 * page. In the case new page is migrated but not remapped, new page's
	 * mapcount will be finally 0 and we call uncharge in end_migration().
	 */
	pc = lookup_page_cgroup(newpage);
	if (PageAnon(page))
		ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
	else if (page_is_file_cache(page))
		ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
	else
		ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
A
Andrea Arcangeli 已提交
2934
	__mem_cgroup_commit_charge(mem, pc, ctype, PAGE_SIZE);
2935
	return ret;
2936
}
2937

2938
/* remove redundant charge if migration failed*/
2939
void mem_cgroup_end_migration(struct mem_cgroup *mem,
2940
	struct page *oldpage, struct page *newpage, bool migration_ok)
2941
{
2942
	struct page *used, *unused;
2943 2944 2945 2946
	struct page_cgroup *pc;

	if (!mem)
		return;
2947
	/* blocks rmdir() */
2948
	cgroup_exclude_rmdir(&mem->css);
2949
	if (!migration_ok) {
2950 2951
		used = oldpage;
		unused = newpage;
2952
	} else {
2953
		used = newpage;
2954 2955
		unused = oldpage;
	}
2956
	/*
2957 2958 2959
	 * 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.
2960
	 */
2961 2962 2963 2964
	pc = lookup_page_cgroup(oldpage);
	lock_page_cgroup(pc);
	ClearPageCgroupMigration(pc);
	unlock_page_cgroup(pc);
2965

2966 2967
	__mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);

2968
	/*
2969 2970 2971 2972 2973 2974
	 * 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)
2975
	 */
2976 2977
	if (PageAnon(used))
		mem_cgroup_uncharge_page(used);
2978
	/*
2979 2980
	 * At migration, we may charge account against cgroup which has no
	 * tasks.
2981 2982 2983 2984
	 * 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);
2985
}
2986

2987
/*
2988 2989 2990 2991 2992 2993
 * 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.
2994
 */
2995
int mem_cgroup_shmem_charge_fallback(struct page *page,
2996 2997
			    struct mm_struct *mm,
			    gfp_t gfp_mask)
2998
{
2999
	struct mem_cgroup *mem = NULL;
3000
	int ret;
3001

3002
	if (mem_cgroup_disabled())
3003
		return 0;
3004

3005 3006 3007
	ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
	if (!ret)
		mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
3008

3009
	return ret;
3010 3011
}

3012 3013
static DEFINE_MUTEX(set_limit_mutex);

3014
static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
3015
				unsigned long long val)
3016
{
3017
	int retry_count;
3018
	u64 memswlimit, memlimit;
3019
	int ret = 0;
3020 3021
	int children = mem_cgroup_count_children(memcg);
	u64 curusage, oldusage;
3022
	int enlarge;
3023 3024 3025 3026 3027 3028 3029 3030 3031

	/*
	 * 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);
3032

3033
	enlarge = 0;
3034
	while (retry_count) {
3035 3036 3037 3038
		if (signal_pending(current)) {
			ret = -EINTR;
			break;
		}
3039 3040 3041 3042 3043 3044 3045 3046 3047 3048
		/*
		 * 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);
3049 3050
			break;
		}
3051 3052 3053 3054 3055

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

3056
		ret = res_counter_set_limit(&memcg->res, val);
3057 3058 3059 3060 3061 3062
		if (!ret) {
			if (memswlimit == val)
				memcg->memsw_is_minimum = true;
			else
				memcg->memsw_is_minimum = false;
		}
3063 3064 3065 3066 3067
		mutex_unlock(&set_limit_mutex);

		if (!ret)
			break;

3068
		mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3069
						MEM_CGROUP_RECLAIM_SHRINK);
3070 3071 3072 3073 3074 3075
		curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
		/* Usage is reduced ? */
  		if (curusage >= oldusage)
			retry_count--;
		else
			oldusage = curusage;
3076
	}
3077 3078
	if (!ret && enlarge)
		memcg_oom_recover(memcg);
3079

3080 3081 3082
	return ret;
}

L
Li Zefan 已提交
3083 3084
static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
					unsigned long long val)
3085
{
3086
	int retry_count;
3087
	u64 memlimit, memswlimit, oldusage, curusage;
3088 3089
	int children = mem_cgroup_count_children(memcg);
	int ret = -EBUSY;
3090
	int enlarge = 0;
3091

3092 3093 3094
	/* see mem_cgroup_resize_res_limit */
 	retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
	oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111
	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;
		}
3112 3113 3114
		memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
		if (memswlimit < val)
			enlarge = 1;
3115
		ret = res_counter_set_limit(&memcg->memsw, val);
3116 3117 3118 3119 3120 3121
		if (!ret) {
			if (memlimit == val)
				memcg->memsw_is_minimum = true;
			else
				memcg->memsw_is_minimum = false;
		}
3122 3123 3124 3125 3126
		mutex_unlock(&set_limit_mutex);

		if (!ret)
			break;

3127
		mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3128 3129
						MEM_CGROUP_RECLAIM_NOSWAP |
						MEM_CGROUP_RECLAIM_SHRINK);
3130
		curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3131
		/* Usage is reduced ? */
3132
		if (curusage >= oldusage)
3133
			retry_count--;
3134 3135
		else
			oldusage = curusage;
3136
	}
3137 3138
	if (!ret && enlarge)
		memcg_oom_recover(memcg);
3139 3140 3141
	return ret;
}

3142
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3143
					    gfp_t gfp_mask)
3144 3145 3146 3147 3148 3149
{
	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;
3150
	unsigned long long excess;
3151 3152 3153 3154

	if (order > 0)
		return 0;

3155
	mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202
	/*
	 * 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);
3203
		excess = res_counter_soft_limit_excess(&mz->mem->res);
3204 3205 3206 3207 3208 3209 3210 3211
		/*
		 * 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.
		 */
3212 3213
		/* If excess == 0, no tree ops */
		__mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess);
3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231
		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;
}

3232 3233 3234 3235
/*
 * This routine traverse page_cgroup in given list and drop them all.
 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
 */
3236
static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
K
KAMEZAWA Hiroyuki 已提交
3237
				int node, int zid, enum lru_list lru)
3238
{
K
KAMEZAWA Hiroyuki 已提交
3239 3240
	struct zone *zone;
	struct mem_cgroup_per_zone *mz;
3241
	struct page_cgroup *pc, *busy;
K
KAMEZAWA Hiroyuki 已提交
3242
	unsigned long flags, loop;
3243
	struct list_head *list;
3244
	int ret = 0;
3245

K
KAMEZAWA Hiroyuki 已提交
3246 3247
	zone = &NODE_DATA(node)->node_zones[zid];
	mz = mem_cgroup_zoneinfo(mem, node, zid);
3248
	list = &mz->lists[lru];
3249

3250 3251 3252 3253 3254 3255
	loop = MEM_CGROUP_ZSTAT(mz, lru);
	/* give some margin against EBUSY etc...*/
	loop += 256;
	busy = NULL;
	while (loop--) {
		ret = 0;
K
KAMEZAWA Hiroyuki 已提交
3256
		spin_lock_irqsave(&zone->lru_lock, flags);
3257
		if (list_empty(list)) {
K
KAMEZAWA Hiroyuki 已提交
3258
			spin_unlock_irqrestore(&zone->lru_lock, flags);
3259
			break;
3260 3261 3262 3263
		}
		pc = list_entry(list->prev, struct page_cgroup, lru);
		if (busy == pc) {
			list_move(&pc->lru, list);
3264
			busy = NULL;
K
KAMEZAWA Hiroyuki 已提交
3265
			spin_unlock_irqrestore(&zone->lru_lock, flags);
3266 3267
			continue;
		}
K
KAMEZAWA Hiroyuki 已提交
3268
		spin_unlock_irqrestore(&zone->lru_lock, flags);
3269

K
KAMEZAWA Hiroyuki 已提交
3270
		ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL);
3271
		if (ret == -ENOMEM)
3272
			break;
3273 3274 3275 3276 3277 3278 3279

		if (ret == -EBUSY || ret == -EINVAL) {
			/* found lock contention or "pc" is obsolete. */
			busy = pc;
			cond_resched();
		} else
			busy = NULL;
3280
	}
K
KAMEZAWA Hiroyuki 已提交
3281

3282 3283 3284
	if (!ret && !list_empty(list))
		return -EBUSY;
	return ret;
3285 3286 3287 3288 3289 3290
}

/*
 * make mem_cgroup's charge to be 0 if there is no task.
 * This enables deleting this mem_cgroup.
 */
3291
static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
3292
{
3293 3294 3295
	int ret;
	int node, zid, shrink;
	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3296
	struct cgroup *cgrp = mem->css.cgroup;
3297

3298
	css_get(&mem->css);
3299 3300

	shrink = 0;
3301 3302 3303
	/* should free all ? */
	if (free_all)
		goto try_to_free;
3304
move_account:
3305
	do {
3306
		ret = -EBUSY;
3307 3308 3309 3310
		if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
			goto out;
		ret = -EINTR;
		if (signal_pending(current))
3311
			goto out;
3312 3313
		/* This is for making all *used* pages to be on LRU. */
		lru_add_drain_all();
3314
		drain_all_stock_sync();
3315
		ret = 0;
3316
		mem_cgroup_start_move(mem);
3317
		for_each_node_state(node, N_HIGH_MEMORY) {
3318
			for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
3319
				enum lru_list l;
3320 3321
				for_each_lru(l) {
					ret = mem_cgroup_force_empty_list(mem,
K
KAMEZAWA Hiroyuki 已提交
3322
							node, zid, l);
3323 3324 3325
					if (ret)
						break;
				}
3326
			}
3327 3328 3329
			if (ret)
				break;
		}
3330
		mem_cgroup_end_move(mem);
3331
		memcg_oom_recover(mem);
3332 3333 3334
		/* it seems parent cgroup doesn't have enough mem */
		if (ret == -ENOMEM)
			goto try_to_free;
3335
		cond_resched();
3336 3337
	/* "ret" should also be checked to ensure all lists are empty. */
	} while (mem->res.usage > 0 || ret);
3338 3339 3340
out:
	css_put(&mem->css);
	return ret;
3341 3342

try_to_free:
3343 3344
	/* returns EBUSY if there is a task or if we come here twice. */
	if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
3345 3346 3347
		ret = -EBUSY;
		goto out;
	}
3348 3349
	/* we call try-to-free pages for make this cgroup empty */
	lru_add_drain_all();
3350 3351 3352 3353
	/* try to free all pages in this cgroup */
	shrink = 1;
	while (nr_retries && mem->res.usage > 0) {
		int progress;
3354 3355 3356 3357 3358

		if (signal_pending(current)) {
			ret = -EINTR;
			goto out;
		}
K
KOSAKI Motohiro 已提交
3359 3360
		progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
						false, get_swappiness(mem));
3361
		if (!progress) {
3362
			nr_retries--;
3363
			/* maybe some writeback is necessary */
3364
			congestion_wait(BLK_RW_ASYNC, HZ/10);
3365
		}
3366 3367

	}
K
KAMEZAWA Hiroyuki 已提交
3368
	lru_add_drain();
3369
	/* try move_account...there may be some *locked* pages. */
3370
	goto move_account;
3371 3372
}

3373 3374 3375 3376 3377 3378
int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
{
	return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
}


3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396
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();
	/*
3397
	 * If parent's use_hierarchy is set, we can't make any modifications
3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416
	 * 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;
}

3417

K
KAMEZAWA Hiroyuki 已提交
3418 3419
static u64 mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem,
				enum mem_cgroup_stat_index idx)
3420
{
K
KAMEZAWA Hiroyuki 已提交
3421 3422
	struct mem_cgroup *iter;
	s64 val = 0;
3423

K
KAMEZAWA Hiroyuki 已提交
3424 3425 3426 3427 3428 3429 3430
	/* each per cpu's value can be minus.Then, use s64 */
	for_each_mem_cgroup_tree(iter, mem)
		val += mem_cgroup_read_stat(iter, idx);

	if (val < 0) /* race ? */
		val = 0;
	return val;
3431 3432
}

3433 3434
static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap)
{
K
KAMEZAWA Hiroyuki 已提交
3435
	u64 val;
3436 3437 3438 3439 3440 3441 3442 3443

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

K
KAMEZAWA Hiroyuki 已提交
3444 3445
	val = mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_CACHE);
	val += mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_RSS);
3446

K
KAMEZAWA Hiroyuki 已提交
3447 3448 3449
	if (swap)
		val += mem_cgroup_get_recursive_idx_stat(mem,
				MEM_CGROUP_STAT_SWAPOUT);
3450 3451 3452 3453

	return val << PAGE_SHIFT;
}

3454
static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
B
Balbir Singh 已提交
3455
{
3456
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3457
	u64 val;
3458 3459 3460 3461 3462 3463
	int type, name;

	type = MEMFILE_TYPE(cft->private);
	name = MEMFILE_ATTR(cft->private);
	switch (type) {
	case _MEM:
3464 3465 3466
		if (name == RES_USAGE)
			val = mem_cgroup_usage(mem, false);
		else
3467
			val = res_counter_read_u64(&mem->res, name);
3468 3469
		break;
	case _MEMSWAP:
3470 3471 3472
		if (name == RES_USAGE)
			val = mem_cgroup_usage(mem, true);
		else
3473
			val = res_counter_read_u64(&mem->memsw, name);
3474 3475 3476 3477 3478 3479
		break;
	default:
		BUG();
		break;
	}
	return val;
B
Balbir Singh 已提交
3480
}
3481 3482 3483 3484
/*
 * The user of this function is...
 * RES_LIMIT.
 */
3485 3486
static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
			    const char *buffer)
B
Balbir Singh 已提交
3487
{
3488
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3489
	int type, name;
3490 3491 3492
	unsigned long long val;
	int ret;

3493 3494 3495
	type = MEMFILE_TYPE(cft->private);
	name = MEMFILE_ATTR(cft->private);
	switch (name) {
3496
	case RES_LIMIT:
3497 3498 3499 3500
		if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
			ret = -EINVAL;
			break;
		}
3501 3502
		/* This function does all necessary parse...reuse it */
		ret = res_counter_memparse_write_strategy(buffer, &val);
3503 3504 3505
		if (ret)
			break;
		if (type == _MEM)
3506
			ret = mem_cgroup_resize_limit(memcg, val);
3507 3508
		else
			ret = mem_cgroup_resize_memsw_limit(memcg, val);
3509
		break;
3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523
	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;
3524 3525 3526 3527 3528
	default:
		ret = -EINVAL; /* should be BUG() ? */
		break;
	}
	return ret;
B
Balbir Singh 已提交
3529 3530
}

3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558
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;
}

3559
static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
3560 3561
{
	struct mem_cgroup *mem;
3562
	int type, name;
3563 3564

	mem = mem_cgroup_from_cont(cont);
3565 3566 3567
	type = MEMFILE_TYPE(event);
	name = MEMFILE_ATTR(event);
	switch (name) {
3568
	case RES_MAX_USAGE:
3569 3570 3571 3572
		if (type == _MEM)
			res_counter_reset_max(&mem->res);
		else
			res_counter_reset_max(&mem->memsw);
3573 3574
		break;
	case RES_FAILCNT:
3575 3576 3577 3578
		if (type == _MEM)
			res_counter_reset_failcnt(&mem->res);
		else
			res_counter_reset_failcnt(&mem->memsw);
3579 3580
		break;
	}
3581

3582
	return 0;
3583 3584
}

3585 3586 3587 3588 3589 3590
static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
					struct cftype *cft)
{
	return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
}

3591
#ifdef CONFIG_MMU
3592 3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609
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;
}
3610 3611 3612 3613 3614 3615 3616
#else
static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
					struct cftype *cft, u64 val)
{
	return -ENOSYS;
}
#endif
3617

K
KAMEZAWA Hiroyuki 已提交
3618 3619 3620 3621 3622

/* For read statistics */
enum {
	MCS_CACHE,
	MCS_RSS,
3623
	MCS_FILE_MAPPED,
K
KAMEZAWA Hiroyuki 已提交
3624 3625
	MCS_PGPGIN,
	MCS_PGPGOUT,
3626
	MCS_SWAP,
K
KAMEZAWA Hiroyuki 已提交
3627 3628 3629 3630 3631 3632 3633 3634 3635 3636
	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];
3637 3638
};

K
KAMEZAWA Hiroyuki 已提交
3639 3640 3641 3642 3643 3644
struct {
	char *local_name;
	char *total_name;
} memcg_stat_strings[NR_MCS_STAT] = {
	{"cache", "total_cache"},
	{"rss", "total_rss"},
3645
	{"mapped_file", "total_mapped_file"},
K
KAMEZAWA Hiroyuki 已提交
3646 3647
	{"pgpgin", "total_pgpgin"},
	{"pgpgout", "total_pgpgout"},
3648
	{"swap", "total_swap"},
K
KAMEZAWA Hiroyuki 已提交
3649 3650 3651 3652 3653 3654 3655 3656
	{"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
3657 3658
static void
mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
K
KAMEZAWA Hiroyuki 已提交
3659 3660 3661 3662
{
	s64 val;

	/* per cpu stat */
3663
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
K
KAMEZAWA Hiroyuki 已提交
3664
	s->stat[MCS_CACHE] += val * PAGE_SIZE;
3665
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
K
KAMEZAWA Hiroyuki 已提交
3666
	s->stat[MCS_RSS] += val * PAGE_SIZE;
3667
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED);
3668
	s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
3669
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGIN_COUNT);
K
KAMEZAWA Hiroyuki 已提交
3670
	s->stat[MCS_PGPGIN] += val;
3671
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGOUT_COUNT);
K
KAMEZAWA Hiroyuki 已提交
3672
	s->stat[MCS_PGPGOUT] += val;
3673
	if (do_swap_account) {
3674
		val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
3675 3676
		s->stat[MCS_SWAP] += val * PAGE_SIZE;
	}
K
KAMEZAWA Hiroyuki 已提交
3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693

	/* 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
3694 3695 3696 3697
	struct mem_cgroup *iter;

	for_each_mem_cgroup_tree(iter, mem)
		mem_cgroup_get_local_stat(iter, s);
K
KAMEZAWA Hiroyuki 已提交
3698 3699
}

3700 3701
static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
				 struct cgroup_map_cb *cb)
3702 3703
{
	struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
K
KAMEZAWA Hiroyuki 已提交
3704
	struct mcs_total_stat mystat;
3705 3706
	int i;

K
KAMEZAWA Hiroyuki 已提交
3707 3708
	memset(&mystat, 0, sizeof(mystat));
	mem_cgroup_get_local_stat(mem_cont, &mystat);
3709

3710 3711 3712
	for (i = 0; i < NR_MCS_STAT; i++) {
		if (i == MCS_SWAP && !do_swap_account)
			continue;
K
KAMEZAWA Hiroyuki 已提交
3713
		cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
3714
	}
L
Lee Schermerhorn 已提交
3715

K
KAMEZAWA Hiroyuki 已提交
3716
	/* Hierarchical information */
3717 3718 3719 3720 3721 3722 3723
	{
		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
3724

K
KAMEZAWA Hiroyuki 已提交
3725 3726
	memset(&mystat, 0, sizeof(mystat));
	mem_cgroup_get_total_stat(mem_cont, &mystat);
3727 3728 3729
	for (i = 0; i < NR_MCS_STAT; i++) {
		if (i == MCS_SWAP && !do_swap_account)
			continue;
K
KAMEZAWA Hiroyuki 已提交
3730
		cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
3731
	}
K
KAMEZAWA Hiroyuki 已提交
3732

K
KOSAKI Motohiro 已提交
3733
#ifdef CONFIG_DEBUG_VM
3734
	cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
K
KOSAKI Motohiro 已提交
3735 3736 3737 3738 3739 3740 3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755 3756 3757 3758 3759 3760 3761

	{
		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

3762 3763 3764
	return 0;
}

K
KOSAKI Motohiro 已提交
3765 3766 3767 3768 3769 3770 3771 3772 3773 3774 3775 3776
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;
3777

K
KOSAKI Motohiro 已提交
3778 3779 3780 3781 3782 3783 3784
	if (val > 100)
		return -EINVAL;

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

	parent = mem_cgroup_from_cont(cgrp->parent);
3785 3786 3787

	cgroup_lock();

K
KOSAKI Motohiro 已提交
3788 3789
	/* If under hierarchy, only empty-root can set this value */
	if ((parent->use_hierarchy) ||
3790 3791
	    (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
		cgroup_unlock();
K
KOSAKI Motohiro 已提交
3792
		return -EINVAL;
3793
	}
K
KOSAKI Motohiro 已提交
3794 3795 3796 3797 3798

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

3799 3800
	cgroup_unlock();

K
KOSAKI Motohiro 已提交
3801 3802 3803
	return 0;
}

3804 3805 3806 3807 3808 3809 3810 3811
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)
3812
		t = rcu_dereference(memcg->thresholds.primary);
3813
	else
3814
		t = rcu_dereference(memcg->memsw_thresholds.primary);
3815 3816 3817 3818 3819 3820 3821 3822 3823 3824 3825

	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().
	 */
3826
	i = t->current_threshold;
3827 3828 3829 3830 3831 3832 3833 3834 3835 3836 3837 3838 3839 3840 3841 3842 3843 3844 3845 3846 3847 3848 3849

	/*
	 * 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 */
3850
	t->current_threshold = i - 1;
3851 3852 3853 3854 3855 3856
unlock:
	rcu_read_unlock();
}

static void mem_cgroup_threshold(struct mem_cgroup *memcg)
{
3857 3858 3859 3860 3861 3862 3863
	while (memcg) {
		__mem_cgroup_threshold(memcg, false);
		if (do_swap_account)
			__mem_cgroup_threshold(memcg, true);

		memcg = parent_mem_cgroup(memcg);
	}
3864 3865 3866 3867 3868 3869 3870 3871 3872 3873
}

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
3874
static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem)
K
KAMEZAWA Hiroyuki 已提交
3875 3876 3877 3878 3879 3880 3881 3882 3883 3884
{
	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
3885 3886 3887 3888
	struct mem_cgroup *iter;

	for_each_mem_cgroup_tree(iter, mem)
		mem_cgroup_oom_notify_cb(iter);
K
KAMEZAWA Hiroyuki 已提交
3889 3890 3891 3892
}

static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
	struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
3893 3894
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3895 3896
	struct mem_cgroup_thresholds *thresholds;
	struct mem_cgroup_threshold_ary *new;
3897 3898
	int type = MEMFILE_TYPE(cft->private);
	u64 threshold, usage;
3899
	int i, size, ret;
3900 3901 3902 3903 3904 3905

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

	mutex_lock(&memcg->thresholds_lock);
3906

3907
	if (type == _MEM)
3908
		thresholds = &memcg->thresholds;
3909
	else if (type == _MEMSWAP)
3910
		thresholds = &memcg->memsw_thresholds;
3911 3912 3913 3914 3915 3916
	else
		BUG();

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

	/* Check if a threshold crossed before adding a new one */
3917
	if (thresholds->primary)
3918 3919
		__mem_cgroup_threshold(memcg, type == _MEMSWAP);

3920
	size = thresholds->primary ? thresholds->primary->size + 1 : 1;
3921 3922

	/* Allocate memory for new array of thresholds */
3923
	new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
3924
			GFP_KERNEL);
3925
	if (!new) {
3926 3927 3928
		ret = -ENOMEM;
		goto unlock;
	}
3929
	new->size = size;
3930 3931

	/* Copy thresholds (if any) to new array */
3932 3933
	if (thresholds->primary) {
		memcpy(new->entries, thresholds->primary->entries, (size - 1) *
3934
				sizeof(struct mem_cgroup_threshold));
3935 3936
	}

3937
	/* Add new threshold */
3938 3939
	new->entries[size - 1].eventfd = eventfd;
	new->entries[size - 1].threshold = threshold;
3940 3941

	/* Sort thresholds. Registering of new threshold isn't time-critical */
3942
	sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
3943 3944 3945
			compare_thresholds, NULL);

	/* Find current threshold */
3946
	new->current_threshold = -1;
3947
	for (i = 0; i < size; i++) {
3948
		if (new->entries[i].threshold < usage) {
3949
			/*
3950 3951
			 * new->current_threshold will not be used until
			 * rcu_assign_pointer(), so it's safe to increment
3952 3953
			 * it here.
			 */
3954
			++new->current_threshold;
3955 3956 3957
		}
	}

3958 3959 3960 3961 3962
	/* Free old spare buffer and save old primary buffer as spare */
	kfree(thresholds->spare);
	thresholds->spare = thresholds->primary;

	rcu_assign_pointer(thresholds->primary, new);
3963

3964
	/* To be sure that nobody uses thresholds */
3965 3966 3967 3968 3969 3970 3971 3972
	synchronize_rcu();

unlock:
	mutex_unlock(&memcg->thresholds_lock);

	return ret;
}

3973
static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
K
KAMEZAWA Hiroyuki 已提交
3974
	struct cftype *cft, struct eventfd_ctx *eventfd)
3975 3976
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3977 3978
	struct mem_cgroup_thresholds *thresholds;
	struct mem_cgroup_threshold_ary *new;
3979 3980
	int type = MEMFILE_TYPE(cft->private);
	u64 usage;
3981
	int i, j, size;
3982 3983 3984

	mutex_lock(&memcg->thresholds_lock);
	if (type == _MEM)
3985
		thresholds = &memcg->thresholds;
3986
	else if (type == _MEMSWAP)
3987
		thresholds = &memcg->memsw_thresholds;
3988 3989 3990 3991 3992 3993 3994 3995 3996 3997 3998 3999 4000 4001 4002
	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 */
4003 4004 4005
	size = 0;
	for (i = 0; i < thresholds->primary->size; i++) {
		if (thresholds->primary->entries[i].eventfd != eventfd)
4006 4007 4008
			size++;
	}

4009
	new = thresholds->spare;
4010

4011 4012
	/* Set thresholds array to NULL if we don't have thresholds */
	if (!size) {
4013 4014
		kfree(new);
		new = NULL;
4015
		goto swap_buffers;
4016 4017
	}

4018
	new->size = size;
4019 4020

	/* Copy thresholds and find current threshold */
4021 4022 4023
	new->current_threshold = -1;
	for (i = 0, j = 0; i < thresholds->primary->size; i++) {
		if (thresholds->primary->entries[i].eventfd == eventfd)
4024 4025
			continue;

4026 4027
		new->entries[j] = thresholds->primary->entries[i];
		if (new->entries[j].threshold < usage) {
4028
			/*
4029
			 * new->current_threshold will not be used
4030 4031 4032
			 * until rcu_assign_pointer(), so it's safe to increment
			 * it here.
			 */
4033
			++new->current_threshold;
4034 4035 4036 4037
		}
		j++;
	}

4038
swap_buffers:
4039 4040 4041
	/* Swap primary and spare array */
	thresholds->spare = thresholds->primary;
	rcu_assign_pointer(thresholds->primary, new);
4042

4043
	/* To be sure that nobody uses thresholds */
4044 4045 4046 4047
	synchronize_rcu();

	mutex_unlock(&memcg->thresholds_lock);
}
4048

K
KAMEZAWA Hiroyuki 已提交
4049 4050 4051 4052 4053 4054 4055 4056 4057 4058 4059 4060 4061 4062 4063 4064 4065 4066 4067 4068 4069 4070 4071 4072 4073
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;
}

4074
static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
K
KAMEZAWA Hiroyuki 已提交
4075 4076 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089 4090 4091 4092 4093 4094
	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);
}

4095 4096 4097 4098 4099 4100 4101 4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128
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;
4129 4130
	if (!val)
		memcg_oom_recover(mem);
4131 4132 4133 4134
	cgroup_unlock();
	return 0;
}

B
Balbir Singh 已提交
4135 4136
static struct cftype mem_cgroup_files[] = {
	{
4137
		.name = "usage_in_bytes",
4138
		.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4139
		.read_u64 = mem_cgroup_read,
K
KAMEZAWA Hiroyuki 已提交
4140 4141
		.register_event = mem_cgroup_usage_register_event,
		.unregister_event = mem_cgroup_usage_unregister_event,
B
Balbir Singh 已提交
4142
	},
4143 4144
	{
		.name = "max_usage_in_bytes",
4145
		.private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4146
		.trigger = mem_cgroup_reset,
4147 4148
		.read_u64 = mem_cgroup_read,
	},
B
Balbir Singh 已提交
4149
	{
4150
		.name = "limit_in_bytes",
4151
		.private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4152
		.write_string = mem_cgroup_write,
4153
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
4154
	},
4155 4156 4157 4158 4159 4160
	{
		.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
4161 4162
	{
		.name = "failcnt",
4163
		.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4164
		.trigger = mem_cgroup_reset,
4165
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
4166
	},
4167 4168
	{
		.name = "stat",
4169
		.read_map = mem_control_stat_show,
4170
	},
4171 4172 4173 4174
	{
		.name = "force_empty",
		.trigger = mem_cgroup_force_empty_write,
	},
4175 4176 4177 4178 4179
	{
		.name = "use_hierarchy",
		.write_u64 = mem_cgroup_hierarchy_write,
		.read_u64 = mem_cgroup_hierarchy_read,
	},
K
KOSAKI Motohiro 已提交
4180 4181 4182 4183 4184
	{
		.name = "swappiness",
		.read_u64 = mem_cgroup_swappiness_read,
		.write_u64 = mem_cgroup_swappiness_write,
	},
4185 4186 4187 4188 4189
	{
		.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
4190 4191
	{
		.name = "oom_control",
4192 4193
		.read_map = mem_cgroup_oom_control_read,
		.write_u64 = mem_cgroup_oom_control_write,
K
KAMEZAWA Hiroyuki 已提交
4194 4195 4196 4197
		.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
4198 4199
};

4200 4201 4202 4203 4204 4205
#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
4206 4207
		.register_event = mem_cgroup_usage_register_event,
		.unregister_event = mem_cgroup_usage_unregister_event,
4208 4209 4210 4211 4212 4213 4214 4215 4216 4217 4218 4219 4220 4221 4222 4223 4224 4225 4226 4227 4228 4229 4230 4231 4232 4233 4234 4235 4236 4237 4238 4239 4240 4241 4242
	},
	{
		.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

4243 4244 4245
static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
	struct mem_cgroup_per_node *pn;
4246
	struct mem_cgroup_per_zone *mz;
4247
	enum lru_list l;
4248
	int zone, tmp = node;
4249 4250 4251 4252 4253 4254 4255 4256
	/*
	 * 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.
	 */
4257 4258
	if (!node_state(node, N_NORMAL_MEMORY))
		tmp = -1;
4259
	pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4260 4261
	if (!pn)
		return 1;
4262

4263
	mem->info.nodeinfo[node] = pn;
4264 4265
	for (zone = 0; zone < MAX_NR_ZONES; zone++) {
		mz = &pn->zoneinfo[zone];
4266 4267
		for_each_lru(l)
			INIT_LIST_HEAD(&mz->lists[l]);
4268
		mz->usage_in_excess = 0;
4269 4270
		mz->on_tree = false;
		mz->mem = mem;
4271
	}
4272 4273 4274
	return 0;
}

4275 4276 4277 4278 4279
static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
	kfree(mem->info.nodeinfo[node]);
}

4280 4281 4282
static struct mem_cgroup *mem_cgroup_alloc(void)
{
	struct mem_cgroup *mem;
4283
	int size = sizeof(struct mem_cgroup);
4284

4285
	/* Can be very big if MAX_NUMNODES is very big */
4286
	if (size < PAGE_SIZE)
4287
		mem = kzalloc(size, GFP_KERNEL);
4288
	else
4289
		mem = vzalloc(size);
4290

4291 4292 4293
	if (!mem)
		return NULL;

4294
	mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4295 4296
	if (!mem->stat)
		goto out_free;
4297
	spin_lock_init(&mem->pcp_counter_lock);
4298
	return mem;
4299 4300 4301 4302 4303 4304 4305

out_free:
	if (size < PAGE_SIZE)
		kfree(mem);
	else
		vfree(mem);
	return NULL;
4306 4307
}

4308 4309 4310 4311 4312 4313 4314 4315 4316 4317 4318
/*
 * 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.
 */

4319
static void __mem_cgroup_free(struct mem_cgroup *mem)
4320
{
K
KAMEZAWA Hiroyuki 已提交
4321 4322
	int node;

4323
	mem_cgroup_remove_from_trees(mem);
K
KAMEZAWA Hiroyuki 已提交
4324 4325
	free_css_id(&mem_cgroup_subsys, &mem->css);

K
KAMEZAWA Hiroyuki 已提交
4326 4327 4328
	for_each_node_state(node, N_POSSIBLE)
		free_mem_cgroup_per_zone_info(mem, node);

4329 4330
	free_percpu(mem->stat);
	if (sizeof(struct mem_cgroup) < PAGE_SIZE)
4331 4332 4333 4334 4335
		kfree(mem);
	else
		vfree(mem);
}

4336 4337 4338 4339 4340
static void mem_cgroup_get(struct mem_cgroup *mem)
{
	atomic_inc(&mem->refcnt);
}

4341
static void __mem_cgroup_put(struct mem_cgroup *mem, int count)
4342
{
4343
	if (atomic_sub_and_test(count, &mem->refcnt)) {
4344
		struct mem_cgroup *parent = parent_mem_cgroup(mem);
4345
		__mem_cgroup_free(mem);
4346 4347 4348
		if (parent)
			mem_cgroup_put(parent);
	}
4349 4350
}

4351 4352 4353 4354 4355
static void mem_cgroup_put(struct mem_cgroup *mem)
{
	__mem_cgroup_put(mem, 1);
}

4356 4357 4358 4359 4360 4361 4362 4363 4364
/*
 * 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);
}
4365

4366 4367 4368
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
static void __init enable_swap_cgroup(void)
{
4369
	if (!mem_cgroup_disabled() && really_do_swap_account)
4370 4371 4372 4373 4374 4375 4376 4377
		do_swap_account = 1;
}
#else
static void __init enable_swap_cgroup(void)
{
}
#endif

4378 4379 4380 4381 4382 4383 4384 4385 4386 4387 4388 4389 4390 4391 4392 4393 4394 4395 4396 4397 4398 4399 4400 4401 4402
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
4403
static struct cgroup_subsys_state * __ref
B
Balbir Singh 已提交
4404 4405
mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
{
4406
	struct mem_cgroup *mem, *parent;
K
KAMEZAWA Hiroyuki 已提交
4407
	long error = -ENOMEM;
4408
	int node;
B
Balbir Singh 已提交
4409

4410 4411
	mem = mem_cgroup_alloc();
	if (!mem)
K
KAMEZAWA Hiroyuki 已提交
4412
		return ERR_PTR(error);
4413

4414 4415 4416
	for_each_node_state(node, N_POSSIBLE)
		if (alloc_mem_cgroup_per_zone_info(mem, node))
			goto free_out;
4417

4418
	/* root ? */
4419
	if (cont->parent == NULL) {
4420
		int cpu;
4421
		enable_swap_cgroup();
4422
		parent = NULL;
4423
		root_mem_cgroup = mem;
4424 4425
		if (mem_cgroup_soft_limit_tree_init())
			goto free_out;
4426 4427 4428 4429 4430
		for_each_possible_cpu(cpu) {
			struct memcg_stock_pcp *stock =
						&per_cpu(memcg_stock, cpu);
			INIT_WORK(&stock->work, drain_local_stock);
		}
4431
		hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
4432
	} else {
4433
		parent = mem_cgroup_from_cont(cont->parent);
4434
		mem->use_hierarchy = parent->use_hierarchy;
4435
		mem->oom_kill_disable = parent->oom_kill_disable;
4436
	}
4437

4438 4439 4440
	if (parent && parent->use_hierarchy) {
		res_counter_init(&mem->res, &parent->res);
		res_counter_init(&mem->memsw, &parent->memsw);
4441 4442 4443 4444 4445 4446 4447
		/*
		 * 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);
4448 4449 4450 4451
	} else {
		res_counter_init(&mem->res, NULL);
		res_counter_init(&mem->memsw, NULL);
	}
K
KAMEZAWA Hiroyuki 已提交
4452
	mem->last_scanned_child = 0;
K
KOSAKI Motohiro 已提交
4453
	spin_lock_init(&mem->reclaim_param_lock);
K
KAMEZAWA Hiroyuki 已提交
4454
	INIT_LIST_HEAD(&mem->oom_notify);
4455

K
KOSAKI Motohiro 已提交
4456 4457
	if (parent)
		mem->swappiness = get_swappiness(parent);
4458
	atomic_set(&mem->refcnt, 1);
4459
	mem->move_charge_at_immigrate = 0;
4460
	mutex_init(&mem->thresholds_lock);
B
Balbir Singh 已提交
4461
	return &mem->css;
4462
free_out:
4463
	__mem_cgroup_free(mem);
4464
	root_mem_cgroup = NULL;
K
KAMEZAWA Hiroyuki 已提交
4465
	return ERR_PTR(error);
B
Balbir Singh 已提交
4466 4467
}

4468
static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
4469 4470 4471
					struct cgroup *cont)
{
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4472 4473

	return mem_cgroup_force_empty(mem, false);
4474 4475
}

B
Balbir Singh 已提交
4476 4477 4478
static void mem_cgroup_destroy(struct cgroup_subsys *ss,
				struct cgroup *cont)
{
4479 4480 4481
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);

	mem_cgroup_put(mem);
B
Balbir Singh 已提交
4482 4483 4484 4485 4486
}

static int mem_cgroup_populate(struct cgroup_subsys *ss,
				struct cgroup *cont)
{
4487 4488 4489 4490 4491 4492 4493 4494
	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
4495 4496
}

4497
#ifdef CONFIG_MMU
4498
/* Handlers for move charge at task migration. */
4499 4500
#define PRECHARGE_COUNT_AT_ONCE	256
static int mem_cgroup_do_precharge(unsigned long count)
4501
{
4502 4503
	int ret = 0;
	int batch_count = PRECHARGE_COUNT_AT_ONCE;
4504 4505
	struct mem_cgroup *mem = mc.to;

4506 4507 4508 4509 4510 4511 4512 4513 4514 4515 4516 4517 4518 4519 4520 4521 4522 4523 4524 4525 4526 4527 4528 4529 4530 4531 4532 4533 4534 4535 4536 4537 4538 4539 4540
	if (mem_cgroup_is_root(mem)) {
		mc.precharge += count;
		/* we don't need css_get for root */
		return ret;
	}
	/* try to charge at once */
	if (count > 1) {
		struct res_counter *dummy;
		/*
		 * "mem" cannot be under rmdir() because we've already checked
		 * by cgroup_lock_live_cgroup() that it is not removed and we
		 * are still under the same cgroup_mutex. So we can postpone
		 * css_get().
		 */
		if (res_counter_charge(&mem->res, PAGE_SIZE * count, &dummy))
			goto one_by_one;
		if (do_swap_account && res_counter_charge(&mem->memsw,
						PAGE_SIZE * count, &dummy)) {
			res_counter_uncharge(&mem->res, PAGE_SIZE * count);
			goto one_by_one;
		}
		mc.precharge += count;
		return ret;
	}
one_by_one:
	/* fall back to one by one charge */
	while (count--) {
		if (signal_pending(current)) {
			ret = -EINTR;
			break;
		}
		if (!batch_count--) {
			batch_count = PRECHARGE_COUNT_AT_ONCE;
			cond_resched();
		}
A
Andrea Arcangeli 已提交
4541 4542
		ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false,
					      PAGE_SIZE);
4543 4544 4545 4546 4547
		if (ret || !mem)
			/* mem_cgroup_clear_mc() will do uncharge later */
			return -ENOMEM;
		mc.precharge++;
	}
4548 4549 4550 4551 4552 4553 4554 4555
	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
4556
 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4557 4558 4559 4560 4561 4562
 *
 * 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).
4563 4564 4565
 *   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.
4566 4567 4568 4569 4570
 *
 * Called with pte lock held.
 */
union mc_target {
	struct page	*page;
4571
	swp_entry_t	ent;
4572 4573 4574 4575 4576
};

enum mc_target_type {
	MC_TARGET_NONE,	/* not used */
	MC_TARGET_PAGE,
4577
	MC_TARGET_SWAP,
4578 4579
};

D
Daisuke Nishimura 已提交
4580 4581
static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
						unsigned long addr, pte_t ptent)
4582
{
D
Daisuke Nishimura 已提交
4583
	struct page *page = vm_normal_page(vma, addr, ptent);
4584

D
Daisuke Nishimura 已提交
4585 4586 4587 4588 4589 4590
	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;
4591 4592
	} else if (!move_file())
		/* we ignore mapcount for file pages */
D
Daisuke Nishimura 已提交
4593 4594 4595 4596 4597 4598 4599 4600 4601 4602 4603 4604 4605 4606 4607 4608 4609 4610
		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 */
4611 4612
		if (page)
			put_page(page);
D
Daisuke Nishimura 已提交
4613
		return NULL;
4614
	}
D
Daisuke Nishimura 已提交
4615 4616 4617 4618 4619 4620
	if (do_swap_account)
		entry->val = ent.val;

	return page;
}

4621 4622 4623 4624 4625 4626 4627 4628 4629 4630 4631 4632 4633 4634 4635 4636 4637 4638 4639 4640 4641 4642 4643 4644 4645 4646 4647 4648 4649 4650 4651 4652 4653
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
4654 4655 4656 4657 4658 4659 4660 4661 4662 4663 4664 4665
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);
4666 4667
	else if (pte_none(ptent) || pte_file(ptent))
		page = mc_handle_file_pte(vma, addr, ptent, &ent);
D
Daisuke Nishimura 已提交
4668 4669 4670

	if (!page && !ent.val)
		return 0;
4671 4672 4673 4674 4675 4676 4677 4678 4679 4680 4681 4682 4683 4684 4685
	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
4686 4687
	/* There is a swap entry and a page doesn't exist or isn't charged */
	if (ent.val && !ret &&
4688 4689 4690 4691
			css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
		ret = MC_TARGET_SWAP;
		if (target)
			target->ent = ent;
4692 4693 4694 4695 4696 4697 4698 4699 4700 4701 4702 4703
	}
	return ret;
}

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

A
Andrea Arcangeli 已提交
4704
	VM_BUG_ON(pmd_trans_huge(*pmd));
4705 4706 4707 4708 4709 4710 4711
	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();

4712 4713 4714
	return 0;
}

4715 4716 4717 4718 4719
static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
{
	unsigned long precharge;
	struct vm_area_struct *vma;

4720
	down_read(&mm->mmap_sem);
4721 4722 4723 4724 4725 4726 4727 4728 4729 4730 4731
	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);
	}
4732
	up_read(&mm->mmap_sem);
4733 4734 4735 4736 4737 4738 4739 4740 4741

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

	return precharge;
}

static int mem_cgroup_precharge_mc(struct mm_struct *mm)
{
4742 4743 4744 4745 4746
	unsigned long precharge = mem_cgroup_count_precharge(mm);

	VM_BUG_ON(mc.moving_task);
	mc.moving_task = current;
	return mem_cgroup_do_precharge(precharge);
4747 4748
}

4749 4750
/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
static void __mem_cgroup_clear_mc(void)
4751
{
4752 4753 4754
	struct mem_cgroup *from = mc.from;
	struct mem_cgroup *to = mc.to;

4755
	/* we must uncharge all the leftover precharges from mc.to */
4756 4757 4758 4759 4760 4761 4762 4763 4764 4765 4766
	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;
4767
	}
4768 4769 4770 4771 4772 4773 4774 4775 4776 4777 4778 4779 4780 4781 4782 4783 4784 4785 4786
	/* 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;
	}
4787 4788 4789 4790 4791 4792 4793 4794 4795 4796 4797 4798 4799 4800 4801
	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();
4802
	spin_lock(&mc.lock);
4803 4804
	mc.from = NULL;
	mc.to = NULL;
4805
	spin_unlock(&mc.lock);
4806
	mem_cgroup_end_move(from);
4807 4808
}

4809 4810 4811 4812 4813 4814 4815 4816 4817 4818 4819 4820 4821 4822 4823 4824 4825 4826
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 */
4827 4828 4829 4830
		if (mm->owner == p) {
			VM_BUG_ON(mc.from);
			VM_BUG_ON(mc.to);
			VM_BUG_ON(mc.precharge);
4831
			VM_BUG_ON(mc.moved_charge);
4832
			VM_BUG_ON(mc.moved_swap);
4833
			mem_cgroup_start_move(from);
4834
			spin_lock(&mc.lock);
4835 4836
			mc.from = from;
			mc.to = mem;
4837
			spin_unlock(&mc.lock);
4838
			/* We set mc.moving_task later */
4839 4840 4841 4842

			ret = mem_cgroup_precharge_mc(mm);
			if (ret)
				mem_cgroup_clear_mc();
4843 4844
		}
		mmput(mm);
4845 4846 4847 4848 4849 4850 4851 4852 4853
	}
	return ret;
}

static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
				struct cgroup *cgroup,
				struct task_struct *p,
				bool threadgroup)
{
4854
	mem_cgroup_clear_mc();
4855 4856
}

4857 4858 4859
static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
				unsigned long addr, unsigned long end,
				struct mm_walk *walk)
4860
{
4861 4862 4863 4864 4865 4866
	int ret = 0;
	struct vm_area_struct *vma = walk->private;
	pte_t *pte;
	spinlock_t *ptl;

retry:
A
Andrea Arcangeli 已提交
4867
	VM_BUG_ON(pmd_trans_huge(*pmd));
4868 4869 4870 4871 4872 4873 4874
	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;
4875
		swp_entry_t ent;
4876 4877 4878 4879 4880 4881 4882 4883 4884 4885 4886

		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);
4887
			if (!mem_cgroup_move_account(pc,
4888
					mc.from, mc.to, false, PAGE_SIZE)) {
4889
				mc.precharge--;
4890 4891
				/* we uncharge from mc.from later. */
				mc.moved_charge++;
4892 4893 4894 4895 4896
			}
			putback_lru_page(page);
put:			/* is_target_pte_for_mc() gets the page */
			put_page(page);
			break;
4897 4898
		case MC_TARGET_SWAP:
			ent = target.ent;
4899 4900
			if (!mem_cgroup_move_swap_account(ent,
						mc.from, mc.to, false)) {
4901
				mc.precharge--;
4902 4903 4904
				/* we fixup refcnts and charges later. */
				mc.moved_swap++;
			}
4905
			break;
4906 4907 4908 4909 4910 4911 4912 4913 4914 4915 4916 4917 4918 4919
		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.
		 */
4920
		ret = mem_cgroup_do_precharge(1);
4921 4922 4923 4924 4925 4926 4927 4928 4929 4930 4931 4932
		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();
4933 4934 4935 4936 4937 4938 4939 4940 4941 4942 4943 4944 4945
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;
	}
4946 4947 4948 4949 4950 4951 4952 4953 4954 4955 4956 4957 4958 4959 4960 4961 4962 4963
	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;
	}
4964
	up_read(&mm->mmap_sem);
4965 4966
}

B
Balbir Singh 已提交
4967 4968 4969
static void mem_cgroup_move_task(struct cgroup_subsys *ss,
				struct cgroup *cont,
				struct cgroup *old_cont,
4970 4971
				struct task_struct *p,
				bool threadgroup)
B
Balbir Singh 已提交
4972
{
4973 4974 4975
	struct mm_struct *mm;

	if (!mc.to)
4976 4977 4978
		/* no need to move charge */
		return;

4979 4980 4981 4982 4983
	mm = get_task_mm(p);
	if (mm) {
		mem_cgroup_move_charge(mm);
		mmput(mm);
	}
4984
	mem_cgroup_clear_mc();
B
Balbir Singh 已提交
4985
}
4986 4987 4988 4989 4990 4991 4992 4993 4994 4995 4996 4997 4998 4999 5000 5001 5002 5003 5004 5005 5006 5007
#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
5008

B
Balbir Singh 已提交
5009 5010 5011 5012
struct cgroup_subsys mem_cgroup_subsys = {
	.name = "memory",
	.subsys_id = mem_cgroup_subsys_id,
	.create = mem_cgroup_create,
5013
	.pre_destroy = mem_cgroup_pre_destroy,
B
Balbir Singh 已提交
5014 5015
	.destroy = mem_cgroup_destroy,
	.populate = mem_cgroup_populate,
5016 5017
	.can_attach = mem_cgroup_can_attach,
	.cancel_attach = mem_cgroup_cancel_attach,
B
Balbir Singh 已提交
5018
	.attach = mem_cgroup_move_task,
5019
	.early_init = 0,
K
KAMEZAWA Hiroyuki 已提交
5020
	.use_id = 1,
B
Balbir Singh 已提交
5021
};
5022 5023

#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
5024 5025 5026 5027 5028 5029 5030 5031 5032 5033
static int __init enable_swap_account(char *s)
{
	/* consider enabled if no parameter or 1 is given */
	if (!s || !strcmp(s, "1"))
		really_do_swap_account = 1;
	else if (!strcmp(s, "0"))
		really_do_swap_account = 0;
	return 1;
}
__setup("swapaccount", enable_swap_account);
5034 5035 5036

static int __init disable_swap_account(char *s)
{
5037
	enable_swap_account("0");
5038 5039 5040 5041
	return 1;
}
__setup("noswapaccount", disable_swap_account);
#endif