memcontrol.c 131.8 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
		nr_pages = -nr_pages; /* for event */
	}
619 620

	__this_cpu_add(mem->stat->count[MEM_CGROUP_EVENTS], nr_pages);
621

622
	preempt_enable();
623 624
}

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

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

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

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

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

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

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

670
struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
671
{
672 673 674 675 676 677 678 679
	/*
	 * mm_update_next_owner() may clear mm->owner to NULL
	 * if it races with swapoff, page migration, etc.
	 * So this can be called with p == NULL.
	 */
	if (unlikely(!p))
		return NULL;

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

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

	if (!mm)
		return NULL;
690 691 692 693 694 695 696 697 698 699 700 701 702 703 704
	/*
	 * Because we have no locks, mm->owner's may be being moved to other
	 * cgroup. We use css_tryget() here even if this looks
	 * pessimistic (rather than adding locks here).
	 */
	rcu_read_lock();
	do {
		mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
		if (unlikely(!mem))
			break;
	} while (!css_tryget(&mem->css));
	rcu_read_unlock();
	return mem;
}

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

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

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

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

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

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

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

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

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/*
 * Following LRU functions are allowed to be used without PCG_LOCK.
 * Operations are called by routine of global LRU independently from memcg.
 * What we have to take care of here is validness of pc->mem_cgroup.
 *
 * Changes to pc->mem_cgroup happens when
 * 1. charge
 * 2. moving account
 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
 * It is added to LRU before charge.
 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
 * When moving account, the page is not on LRU. It's isolated.
 */
801

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

807
	if (mem_cgroup_disabled())
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		return;
	pc = lookup_page_cgroup(page);
	/* can happen while we handle swapcache. */
811
	if (!TestClearPageCgroupAcctLRU(pc))
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		return;
813
	VM_BUG_ON(!pc->mem_cgroup);
814 815 816 817
	/*
	 * We don't check PCG_USED bit. It's cleared when the "page" is finally
	 * removed from global LRU.
	 */
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	mz = page_cgroup_zoneinfo(pc);
819 820
	/* huge page split is done under lru_lock. so, we have no races. */
	MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page);
821 822 823
	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);
825 826
}

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

832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857
/*
 * Writeback is about to end against a page which has been marked for immediate
 * reclaim.  If it still appears to be reclaimable, move it to the tail of the
 * inactive list.
 */
void mem_cgroup_rotate_reclaimable_page(struct page *page)
{
	struct mem_cgroup_per_zone *mz;
	struct page_cgroup *pc;
	enum lru_list lru = page_lru(page);

	if (mem_cgroup_disabled())
		return;

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

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void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
{
	struct mem_cgroup_per_zone *mz;
	struct page_cgroup *pc;
862

863
	if (mem_cgroup_disabled())
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		return;
865

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	pc = lookup_page_cgroup(page);
867
	/* unused or root page is not rotated. */
868 869 870 871 872
	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]);
876 877
}

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void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
879
{
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	struct page_cgroup *pc;
	struct mem_cgroup_per_zone *mz;
882

883
	if (mem_cgroup_disabled())
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		return;
	pc = lookup_page_cgroup(page);
886
	VM_BUG_ON(PageCgroupAcctLRU(pc));
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	if (!PageCgroupUsed(pc))
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		return;
889 890
	/* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
	smp_rmb();
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	mz = page_cgroup_zoneinfo(pc);
892 893
	/* huge page split is done under lru_lock. so, we have no races. */
	MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page);
894 895 896
	SetPageCgroupAcctLRU(pc);
	if (mem_cgroup_is_root(pc->mem_cgroup))
		return;
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	list_add(&pc->lru, &mz->lists[lru]);
}
899

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/*
901 902 903 904 905
 * 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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 */
907
static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page)
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{
909 910 911 912 913 914 915 916 917 918 919 920
	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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}

923 924 925 926 927 928 929 930
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 */
931
	if (PageLRU(page) && !PageCgroupAcctLRU(pc))
932 933 934 935 936
		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)
{
940
	if (mem_cgroup_disabled())
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		return;
	mem_cgroup_del_lru_list(page, from);
	mem_cgroup_add_lru_list(page, to);
944 945
}

946 947 948
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
{
	int ret;
949
	struct mem_cgroup *curr = NULL;
950
	struct task_struct *p;
951

952 953 954 955 956
	p = find_lock_task_mm(task);
	if (!p)
		return 0;
	curr = try_get_mem_cgroup_from_mm(p->mm);
	task_unlock(p);
957 958
	if (!curr)
		return 0;
959 960 961 962 963 964 965
	/*
	 * 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)
966 967 968 969
		ret = css_is_ancestor(&curr->css, &mem->css);
	else
		ret = (curr == mem);
	css_put(&curr->css);
970 971 972
	return ret;
}

973
static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
974 975 976
{
	unsigned long active;
	unsigned long inactive;
977 978
	unsigned long gb;
	unsigned long inactive_ratio;
979

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	inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON);
	active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON);
982

983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009
	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)
1010 1011 1012 1013 1014
		return 1;

	return 0;
}

1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025
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);
}

1026 1027 1028 1029
unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
				       struct zone *zone,
				       enum lru_list lru)
{
1030
	int nid = zone_to_nid(zone);
1031 1032 1033 1034 1035 1036
	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)
{
1040
	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);
1057 1058
	if (!PageCgroupUsed(pc))
		return NULL;
1059 1060
	/* 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;
}

1068 1069 1070 1071 1072
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,
1073
					int active, int file)
1074 1075 1076 1077 1078 1079
{
	unsigned long nr_taken = 0;
	struct page *page;
	unsigned long scan;
	LIST_HEAD(pc_list);
	struct list_head *src;
1080
	struct page_cgroup *pc, *tmp;
1081
	int nid = zone_to_nid(z);
1082 1083
	int zid = zone_idx(z);
	struct mem_cgroup_per_zone *mz;
1084
	int lru = LRU_FILE * file + active;
1085
	int ret;
1086

1087
	BUG_ON(!mem_cont);
1088
	mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
1089
	src = &mz->lists[lru];
1090

1091 1092
	scan = 0;
	list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
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Hugh Dickins 已提交
1093
		if (scan >= nr_to_scan)
1094
			break;
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		page = pc->page;
1097 1098
		if (unlikely(!PageCgroupUsed(pc)))
			continue;
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Hugh Dickins 已提交
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		if (unlikely(!PageLRU(page)))
1100 1101
			continue;

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		scan++;
1103 1104 1105
		ret = __isolate_lru_page(page, mode, file);
		switch (ret) {
		case 0:
1106
			list_move(&page->lru, dst);
1107
			mem_cgroup_del_lru(page);
1108
			nr_taken += hpage_nr_pages(page);
1109 1110 1111 1112 1113 1114 1115
			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;
1116 1117 1118 1119
		}
	}

	*scanned = scan;
1120 1121 1122 1123

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

1124 1125 1126
	return nr_taken;
}

1127 1128 1129
#define mem_cgroup_from_res_counter(counter, member)	\
	container_of(counter, struct mem_cgroup, member)

1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141
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;
}

1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158
/**
 * mem_cgroup_check_margin - check if the memory cgroup allows charging
 * @mem: memory cgroup to check
 * @bytes: the number of bytes the caller intends to charge
 *
 * Returns a boolean value on whether @mem can be charged @bytes or
 * whether this would exceed the limit.
 */
static bool mem_cgroup_check_margin(struct mem_cgroup *mem, unsigned long bytes)
{
	if (!res_counter_check_margin(&mem->res, bytes))
		return false;
	if (do_swap_account && !res_counter_check_margin(&mem->memsw, bytes))
		return false;
	return true;
}

K
KOSAKI Motohiro 已提交
1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174
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;
}

1175 1176 1177
static void mem_cgroup_start_move(struct mem_cgroup *mem)
{
	int cpu;
1178 1179 1180 1181

	get_online_cpus();
	spin_lock(&mem->pcp_counter_lock);
	for_each_online_cpu(cpu)
1182
		per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1;
1183 1184 1185
	mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1;
	spin_unlock(&mem->pcp_counter_lock);
	put_online_cpus();
1186 1187 1188 1189 1190 1191 1192 1193 1194 1195

	synchronize_rcu();
}

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

	if (!mem)
		return;
1196 1197 1198
	get_online_cpus();
	spin_lock(&mem->pcp_counter_lock);
	for_each_online_cpu(cpu)
1199
		per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1;
1200 1201 1202
	mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1;
	spin_unlock(&mem->pcp_counter_lock);
	put_online_cpus();
1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220
}
/*
 * 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;
}
1221 1222 1223

static bool mem_cgroup_under_move(struct mem_cgroup *mem)
{
1224 1225
	struct mem_cgroup *from;
	struct mem_cgroup *to;
1226
	bool ret = false;
1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241
	/*
	 * 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);
1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260
	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;
}

1261
/**
1262
 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280
 * @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;

1281
	if (!memcg || !p)
1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327
		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));
}

1328 1329 1330 1331 1332 1333 1334
/*
 * This function returns the number of memcg under hierarchy tree. Returns
 * 1(self count) if no children.
 */
static int mem_cgroup_count_children(struct mem_cgroup *mem)
{
	int num = 0;
K
KAMEZAWA Hiroyuki 已提交
1335 1336 1337 1338
	struct mem_cgroup *iter;

	for_each_mem_cgroup_tree(iter, mem)
		num++;
1339 1340 1341
	return num;
}

D
David Rientjes 已提交
1342 1343 1344 1345 1346 1347 1348 1349
/*
 * Return the memory (and swap, if configured) limit for a memcg.
 */
u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
{
	u64 limit;
	u64 memsw;

1350 1351 1352
	limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
	limit += total_swap_pages << PAGE_SHIFT;

D
David Rientjes 已提交
1353 1354 1355 1356 1357 1358 1359 1360
	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);
}

1361
/*
K
KAMEZAWA Hiroyuki 已提交
1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403
 * 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.
1404 1405
 *
 * root_mem is the original ancestor that we've been reclaim from.
K
KAMEZAWA Hiroyuki 已提交
1406 1407 1408
 *
 * We give up and return to the caller when we visit root_mem twice.
 * (other groups can be removed while we're walking....)
1409 1410
 *
 * If shrink==true, for avoiding to free too much, this returns immedieately.
1411 1412
 */
static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
1413
						struct zone *zone,
1414 1415
						gfp_t gfp_mask,
						unsigned long reclaim_options)
1416
{
K
KAMEZAWA Hiroyuki 已提交
1417 1418 1419
	struct mem_cgroup *victim;
	int ret, total = 0;
	int loop = 0;
1420 1421
	bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
	bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
1422 1423
	bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
	unsigned long excess = mem_cgroup_get_excess(root_mem);
K
KAMEZAWA Hiroyuki 已提交
1424

1425 1426 1427 1428
	/* If memsw_is_minimum==1, swap-out is of-no-use. */
	if (root_mem->memsw_is_minimum)
		noswap = true;

1429
	while (1) {
K
KAMEZAWA Hiroyuki 已提交
1430
		victim = mem_cgroup_select_victim(root_mem);
1431
		if (victim == root_mem) {
K
KAMEZAWA Hiroyuki 已提交
1432
			loop++;
1433 1434
			if (loop >= 1)
				drain_all_stock_async();
1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457
			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;
				}
			}
		}
1458
		if (!mem_cgroup_local_usage(victim)) {
K
KAMEZAWA Hiroyuki 已提交
1459 1460
			/* this cgroup's local usage == 0 */
			css_put(&victim->css);
1461 1462
			continue;
		}
K
KAMEZAWA Hiroyuki 已提交
1463
		/* we use swappiness of local cgroup */
1464 1465
		if (check_soft)
			ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
1466
				noswap, get_swappiness(victim), zone);
1467 1468 1469
		else
			ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
						noswap, get_swappiness(victim));
K
KAMEZAWA Hiroyuki 已提交
1470
		css_put(&victim->css);
1471 1472 1473 1474 1475 1476 1477
		/*
		 * At shrinking usage, we can't check we should stop here or
		 * reclaim more. It's depends on callers. last_scanned_child
		 * will work enough for keeping fairness under tree.
		 */
		if (shrink)
			return ret;
K
KAMEZAWA Hiroyuki 已提交
1478
		total += ret;
1479 1480 1481 1482
		if (check_soft) {
			if (res_counter_check_under_soft_limit(&root_mem->res))
				return total;
		} else if (mem_cgroup_check_under_limit(root_mem))
K
KAMEZAWA Hiroyuki 已提交
1483
			return 1 + total;
1484
	}
K
KAMEZAWA Hiroyuki 已提交
1485
	return total;
1486 1487
}

K
KAMEZAWA Hiroyuki 已提交
1488 1489 1490 1491 1492 1493
/*
 * Check OOM-Killer is already running under our hierarchy.
 * If someone is running, return false.
 */
static bool mem_cgroup_oom_lock(struct mem_cgroup *mem)
{
K
KAMEZAWA Hiroyuki 已提交
1494 1495
	int x, lock_count = 0;
	struct mem_cgroup *iter;
1496

K
KAMEZAWA Hiroyuki 已提交
1497 1498 1499 1500
	for_each_mem_cgroup_tree(iter, mem) {
		x = atomic_inc_return(&iter->oom_lock);
		lock_count = max(x, lock_count);
	}
K
KAMEZAWA Hiroyuki 已提交
1501 1502 1503 1504

	if (lock_count == 1)
		return true;
	return false;
1505
}
1506

K
KAMEZAWA Hiroyuki 已提交
1507
static int mem_cgroup_oom_unlock(struct mem_cgroup *mem)
1508
{
K
KAMEZAWA Hiroyuki 已提交
1509 1510
	struct mem_cgroup *iter;

K
KAMEZAWA Hiroyuki 已提交
1511 1512 1513 1514 1515
	/*
	 * When a new child is created while the hierarchy is under oom,
	 * mem_cgroup_oom_lock() may not be called. We have to use
	 * atomic_add_unless() here.
	 */
K
KAMEZAWA Hiroyuki 已提交
1516 1517
	for_each_mem_cgroup_tree(iter, mem)
		atomic_add_unless(&iter->oom_lock, -1, 0);
1518 1519 1520
	return 0;
}

K
KAMEZAWA Hiroyuki 已提交
1521 1522 1523 1524

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

K
KAMEZAWA Hiroyuki 已提交
1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560
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);
}

1561 1562
static void memcg_oom_recover(struct mem_cgroup *mem)
{
1563
	if (mem && atomic_read(&mem->oom_lock))
1564 1565 1566
		memcg_wakeup_oom(mem);
}

K
KAMEZAWA Hiroyuki 已提交
1567 1568 1569 1570
/*
 * 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)
1571
{
K
KAMEZAWA Hiroyuki 已提交
1572
	struct oom_wait_info owait;
1573
	bool locked, need_to_kill;
K
KAMEZAWA Hiroyuki 已提交
1574

K
KAMEZAWA Hiroyuki 已提交
1575 1576 1577 1578 1579
	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);
1580
	need_to_kill = true;
K
KAMEZAWA Hiroyuki 已提交
1581 1582 1583 1584 1585 1586 1587 1588
	/* 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.
	 */
1589 1590 1591 1592
	prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
	if (!locked || mem->oom_kill_disable)
		need_to_kill = false;
	if (locked)
K
KAMEZAWA Hiroyuki 已提交
1593
		mem_cgroup_oom_notify(mem);
K
KAMEZAWA Hiroyuki 已提交
1594 1595
	mutex_unlock(&memcg_oom_mutex);

1596 1597
	if (need_to_kill) {
		finish_wait(&memcg_oom_waitq, &owait.wait);
K
KAMEZAWA Hiroyuki 已提交
1598
		mem_cgroup_out_of_memory(mem, mask);
1599
	} else {
K
KAMEZAWA Hiroyuki 已提交
1600
		schedule();
K
KAMEZAWA Hiroyuki 已提交
1601
		finish_wait(&memcg_oom_waitq, &owait.wait);
K
KAMEZAWA Hiroyuki 已提交
1602 1603 1604
	}
	mutex_lock(&memcg_oom_mutex);
	mem_cgroup_oom_unlock(mem);
K
KAMEZAWA Hiroyuki 已提交
1605
	memcg_wakeup_oom(mem);
K
KAMEZAWA Hiroyuki 已提交
1606 1607 1608 1609 1610 1611 1612
	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;
1613 1614
}

1615 1616 1617
/*
 * Currently used to update mapped file statistics, but the routine can be
 * generalized to update other statistics as well.
1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636
 *
 * 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.
1637
 */
1638

1639 1640
void mem_cgroup_update_page_stat(struct page *page,
				 enum mem_cgroup_page_stat_item idx, int val)
1641 1642
{
	struct mem_cgroup *mem;
1643 1644
	struct page_cgroup *pc = lookup_page_cgroup(page);
	bool need_unlock = false;
1645
	unsigned long uninitialized_var(flags);
1646 1647 1648 1649

	if (unlikely(!pc))
		return;

1650
	rcu_read_lock();
1651
	mem = pc->mem_cgroup;
1652 1653 1654
	if (unlikely(!mem || !PageCgroupUsed(pc)))
		goto out;
	/* pc->mem_cgroup is unstable ? */
1655
	if (unlikely(mem_cgroup_stealed(mem)) || PageTransHuge(page)) {
1656
		/* take a lock against to access pc->mem_cgroup */
1657
		move_lock_page_cgroup(pc, &flags);
1658 1659 1660 1661 1662
		need_unlock = true;
		mem = pc->mem_cgroup;
		if (!mem || !PageCgroupUsed(pc))
			goto out;
	}
1663 1664

	switch (idx) {
1665
	case MEMCG_NR_FILE_MAPPED:
1666 1667 1668
		if (val > 0)
			SetPageCgroupFileMapped(pc);
		else if (!page_mapped(page))
1669
			ClearPageCgroupFileMapped(pc);
1670
		idx = MEM_CGROUP_STAT_FILE_MAPPED;
1671 1672 1673
		break;
	default:
		BUG();
1674
	}
1675

1676 1677
	this_cpu_add(mem->stat->count[idx], val);

1678 1679
out:
	if (unlikely(need_unlock))
1680
		move_unlock_page_cgroup(pc, &flags);
1681 1682
	rcu_read_unlock();
	return;
1683
}
1684
EXPORT_SYMBOL(mem_cgroup_update_page_stat);
1685

1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 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
/*
 * 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.
1747
 * This will be consumed by consume_stock() function, later.
1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798
 */
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);
}

1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813
/*
 * 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;
	}
1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824
	/* 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];
1825 1826 1827 1828
	spin_unlock(&mem->pcp_counter_lock);
}

static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
1829 1830 1831 1832 1833
					unsigned long action,
					void *hcpu)
{
	int cpu = (unsigned long)hcpu;
	struct memcg_stock_pcp *stock;
1834
	struct mem_cgroup *iter;
1835

1836 1837 1838 1839 1840 1841
	if ((action == CPU_ONLINE)) {
		for_each_mem_cgroup_all(iter)
			synchronize_mem_cgroup_on_move(iter, cpu);
		return NOTIFY_OK;
	}

1842
	if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN)
1843
		return NOTIFY_OK;
1844 1845 1846 1847

	for_each_mem_cgroup_all(iter)
		mem_cgroup_drain_pcp_counter(iter, cpu);

1848 1849 1850 1851 1852
	stock = &per_cpu(memcg_stock, cpu);
	drain_stock(stock);
	return NOTIFY_OK;
}

1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879

/* 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;

1880
		res_counter_uncharge(&mem->res, csize);
1881 1882 1883 1884
		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);
1885 1886 1887 1888 1889 1890 1891 1892 1893
	/*
	 * csize can be either a huge page (HPAGE_SIZE), a batch of
	 * regular pages (CHARGE_SIZE), or a single regular page
	 * (PAGE_SIZE).
	 *
	 * Never reclaim on behalf of optional batching, retry with a
	 * single page instead.
	 */
	if (csize == CHARGE_SIZE)
1894 1895 1896 1897 1898 1899
		return CHARGE_RETRY;

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

	ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
1900 1901 1902
					      gfp_mask, flags);
	if (mem_cgroup_check_margin(mem_over_limit, csize))
		return CHARGE_RETRY;
1903
	/*
1904 1905 1906 1907 1908 1909 1910
	 * Even though the limit is exceeded at this point, reclaim
	 * may have been able to free some pages.  Retry the charge
	 * before killing the task.
	 *
	 * Only for regular pages, though: huge pages are rather
	 * unlikely to succeed so close to the limit, and we fall back
	 * to regular pages anyway in case of failure.
1911
	 */
1912
	if (csize == PAGE_SIZE && ret)
1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931
		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;
}

1932 1933 1934
/*
 * Unlike exported interface, "oom" parameter is added. if oom==true,
 * oom-killer can be invoked.
1935
 */
1936
static int __mem_cgroup_try_charge(struct mm_struct *mm,
A
Andrea Arcangeli 已提交
1937 1938 1939
				   gfp_t gfp_mask,
				   struct mem_cgroup **memcg, bool oom,
				   int page_size)
1940
{
1941 1942 1943
	int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
	struct mem_cgroup *mem = NULL;
	int ret;
A
Andrea Arcangeli 已提交
1944
	int csize = max(CHARGE_SIZE, (unsigned long) page_size);
1945

K
KAMEZAWA Hiroyuki 已提交
1946 1947 1948 1949 1950 1951 1952 1953
	/*
	 * 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;
1954

1955
	/*
1956 1957
	 * We always charge the cgroup the mm_struct belongs to.
	 * The mm_struct's mem_cgroup changes on task migration if the
1958 1959 1960
	 * 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
1961 1962 1963 1964
	if (!*memcg && !mm)
		goto bypass;
again:
	if (*memcg) { /* css should be a valid one */
1965
		mem = *memcg;
K
KAMEZAWA Hiroyuki 已提交
1966 1967 1968
		VM_BUG_ON(css_is_removed(&mem->css));
		if (mem_cgroup_is_root(mem))
			goto done;
A
Andrea Arcangeli 已提交
1969
		if (page_size == PAGE_SIZE && consume_stock(mem))
K
KAMEZAWA Hiroyuki 已提交
1970
			goto done;
1971 1972
		css_get(&mem->css);
	} else {
K
KAMEZAWA Hiroyuki 已提交
1973
		struct task_struct *p;
1974

K
KAMEZAWA Hiroyuki 已提交
1975 1976 1977
		rcu_read_lock();
		p = rcu_dereference(mm->owner);
		/*
1978 1979 1980 1981 1982 1983 1984 1985
		 * 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
1986 1987
		 */
		mem = mem_cgroup_from_task(p);
1988
		if (!mem || mem_cgroup_is_root(mem)) {
K
KAMEZAWA Hiroyuki 已提交
1989 1990 1991
			rcu_read_unlock();
			goto done;
		}
A
Andrea Arcangeli 已提交
1992
		if (page_size == PAGE_SIZE && consume_stock(mem)) {
K
KAMEZAWA Hiroyuki 已提交
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
			/*
			 * 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();
	}
2011

2012 2013
	do {
		bool oom_check;
2014

2015
		/* If killed, bypass charge */
K
KAMEZAWA Hiroyuki 已提交
2016 2017
		if (fatal_signal_pending(current)) {
			css_put(&mem->css);
2018
			goto bypass;
K
KAMEZAWA Hiroyuki 已提交
2019
		}
2020

2021 2022 2023 2024
		oom_check = false;
		if (oom && !nr_oom_retries) {
			oom_check = true;
			nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2025
		}
2026

2027
		ret = __mem_cgroup_do_charge(mem, gfp_mask, csize, oom_check);
2028

2029 2030 2031 2032
		switch (ret) {
		case CHARGE_OK:
			break;
		case CHARGE_RETRY: /* not in OOM situation but retry */
A
Andrea Arcangeli 已提交
2033
			csize = page_size;
K
KAMEZAWA Hiroyuki 已提交
2034 2035 2036
			css_put(&mem->css);
			mem = NULL;
			goto again;
2037
		case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
K
KAMEZAWA Hiroyuki 已提交
2038
			css_put(&mem->css);
2039 2040
			goto nomem;
		case CHARGE_NOMEM: /* OOM routine works */
K
KAMEZAWA Hiroyuki 已提交
2041 2042
			if (!oom) {
				css_put(&mem->css);
K
KAMEZAWA Hiroyuki 已提交
2043
				goto nomem;
K
KAMEZAWA Hiroyuki 已提交
2044
			}
2045 2046 2047 2048
			/* If oom, we never return -ENOMEM */
			nr_oom_retries--;
			break;
		case CHARGE_OOM_DIE: /* Killed by OOM Killer */
K
KAMEZAWA Hiroyuki 已提交
2049
			css_put(&mem->css);
K
KAMEZAWA Hiroyuki 已提交
2050
			goto bypass;
2051
		}
2052 2053
	} while (ret != CHARGE_OK);

A
Andrea Arcangeli 已提交
2054 2055
	if (csize > page_size)
		refill_stock(mem, csize - page_size);
K
KAMEZAWA Hiroyuki 已提交
2056
	css_put(&mem->css);
2057
done:
K
KAMEZAWA Hiroyuki 已提交
2058
	*memcg = mem;
2059 2060
	return 0;
nomem:
K
KAMEZAWA Hiroyuki 已提交
2061
	*memcg = NULL;
2062
	return -ENOMEM;
K
KAMEZAWA Hiroyuki 已提交
2063 2064 2065
bypass:
	*memcg = NULL;
	return 0;
2066
}
2067

2068 2069 2070 2071 2072
/*
 * 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().
 */
2073 2074
static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem,
							unsigned long count)
2075 2076
{
	if (!mem_cgroup_is_root(mem)) {
2077
		res_counter_uncharge(&mem->res, PAGE_SIZE * count);
2078
		if (do_swap_account)
2079
			res_counter_uncharge(&mem->memsw, PAGE_SIZE * count);
2080
	}
2081 2082
}

A
Andrea Arcangeli 已提交
2083 2084
static void mem_cgroup_cancel_charge(struct mem_cgroup *mem,
				     int page_size)
2085
{
A
Andrea Arcangeli 已提交
2086
	__mem_cgroup_cancel_charge(mem, page_size >> PAGE_SHIFT);
2087 2088
}

2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107
/*
 * 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);
}

2108
struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2109
{
2110
	struct mem_cgroup *mem = NULL;
2111
	struct page_cgroup *pc;
2112
	unsigned short id;
2113 2114
	swp_entry_t ent;

2115 2116 2117
	VM_BUG_ON(!PageLocked(page));

	pc = lookup_page_cgroup(page);
2118
	lock_page_cgroup(pc);
2119
	if (PageCgroupUsed(pc)) {
2120
		mem = pc->mem_cgroup;
2121 2122
		if (mem && !css_tryget(&mem->css))
			mem = NULL;
2123
	} else if (PageSwapCache(page)) {
2124
		ent.val = page_private(page);
2125 2126 2127 2128 2129 2130
		id = lookup_swap_cgroup(ent);
		rcu_read_lock();
		mem = mem_cgroup_lookup(id);
		if (mem && !css_tryget(&mem->css))
			mem = NULL;
		rcu_read_unlock();
2131
	}
2132
	unlock_page_cgroup(pc);
2133 2134 2135
	return mem;
}

2136 2137 2138 2139
static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
				       struct page_cgroup *pc,
				       enum charge_type ctype,
				       int page_size)
2140
{
2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156
	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.
	 */
2157
	pc->mem_cgroup = mem;
2158 2159 2160 2161 2162 2163 2164
	/*
	 * 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
2165
	smp_wmb();
2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178
	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;
	}
2179

2180
	mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), nr_pages);
2181
	unlock_page_cgroup(pc);
2182 2183 2184 2185 2186
	/*
	 * "charge_statistics" updated event counter. Then, check it.
	 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
	 * if they exceeds softlimit.
	 */
2187
	memcg_check_events(mem, pc->page);
2188
}
2189

2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203
#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;

2204 2205
	if (mem_cgroup_disabled())
		return;
2206
	/*
2207
	 * We have no races with charge/uncharge but will have races with
2208 2209 2210 2211 2212 2213
	 * page state accounting.
	 */
	move_lock_page_cgroup(head_pc, &flags);

	tail_pc->mem_cgroup = head_pc->mem_cgroup;
	smp_wmb(); /* see __commit_charge() */
2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226
	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;
	}
2227 2228 2229 2230 2231
	tail_pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
	move_unlock_page_cgroup(head_pc, &flags);
}
#endif

2232
/**
2233
 * __mem_cgroup_move_account - move account of the page
2234 2235 2236
 * @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.
2237
 * @uncharge: whether we should call uncharge and css_put against @from.
2238 2239
 *
 * The caller must confirm following.
K
KAMEZAWA Hiroyuki 已提交
2240
 * - page is not on LRU (isolate_page() is useful.)
2241
 * - the pc is locked, used, and ->mem_cgroup points to @from.
2242
 *
2243 2244 2245 2246
 * 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".
2247 2248
 */

2249
static void __mem_cgroup_move_account(struct page_cgroup *pc,
2250 2251
	struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge,
	int charge_size)
2252
{
2253 2254
	int nr_pages = charge_size >> PAGE_SHIFT;

2255
	VM_BUG_ON(from == to);
K
KAMEZAWA Hiroyuki 已提交
2256
	VM_BUG_ON(PageLRU(pc->page));
2257
	VM_BUG_ON(!page_is_cgroup_locked(pc));
2258 2259
	VM_BUG_ON(!PageCgroupUsed(pc));
	VM_BUG_ON(pc->mem_cgroup != from);
2260

2261
	if (PageCgroupFileMapped(pc)) {
2262 2263 2264 2265 2266
		/* 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();
2267
	}
2268
	mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages);
2269 2270
	if (uncharge)
		/* This is not "cancel", but cancel_charge does all we need. */
2271
		mem_cgroup_cancel_charge(from, charge_size);
2272

2273
	/* caller should have done css_get */
K
KAMEZAWA Hiroyuki 已提交
2274
	pc->mem_cgroup = to;
2275
	mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages);
2276 2277 2278
	/*
	 * We charges against "to" which may not have any tasks. Then, "to"
	 * can be under rmdir(). But in current implementation, caller of
2279 2280 2281
	 * 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.
2282
	 */
2283 2284 2285 2286 2287 2288 2289
}

/*
 * 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,
2290 2291
		struct mem_cgroup *from, struct mem_cgroup *to,
		bool uncharge, int charge_size)
2292 2293
{
	int ret = -EINVAL;
2294
	unsigned long flags;
2295 2296 2297 2298 2299 2300
	/*
	 * 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.
	 */
2301 2302 2303
	if ((charge_size > PAGE_SIZE) && !PageTransHuge(pc->page))
		return -EBUSY;

2304 2305
	lock_page_cgroup(pc);
	if (PageCgroupUsed(pc) && pc->mem_cgroup == from) {
2306
		move_lock_page_cgroup(pc, &flags);
2307
		__mem_cgroup_move_account(pc, from, to, uncharge, charge_size);
2308
		move_unlock_page_cgroup(pc, &flags);
2309 2310 2311
		ret = 0;
	}
	unlock_page_cgroup(pc);
2312 2313 2314 2315 2316
	/*
	 * check events
	 */
	memcg_check_events(to, pc->page);
	memcg_check_events(from, pc->page);
2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327
	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
2328
	struct page *page = pc->page;
2329 2330 2331
	struct cgroup *cg = child->css.cgroup;
	struct cgroup *pcg = cg->parent;
	struct mem_cgroup *parent;
2332
	int page_size = PAGE_SIZE;
2333
	unsigned long flags;
2334 2335 2336 2337 2338 2339
	int ret;

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

2340 2341 2342 2343 2344
	ret = -EBUSY;
	if (!get_page_unless_zero(page))
		goto out;
	if (isolate_lru_page(page))
		goto put;
2345 2346 2347

	if (PageTransHuge(page))
		page_size = HPAGE_SIZE;
K
KAMEZAWA Hiroyuki 已提交
2348

2349
	parent = mem_cgroup_from_cont(pcg);
2350 2351
	ret = __mem_cgroup_try_charge(NULL, gfp_mask,
				&parent, false, page_size);
2352
	if (ret || !parent)
2353
		goto put_back;
2354

2355
	if (page_size > PAGE_SIZE)
2356 2357
		flags = compound_lock_irqsave(page);

2358
	ret = mem_cgroup_move_account(pc, child, parent, true, page_size);
2359
	if (ret)
2360
		mem_cgroup_cancel_charge(parent, page_size);
2361

2362
	if (page_size > PAGE_SIZE)
2363
		compound_unlock_irqrestore(page, flags);
2364
put_back:
K
KAMEZAWA Hiroyuki 已提交
2365
	putback_lru_page(page);
2366
put:
2367
	put_page(page);
2368
out:
2369 2370 2371
	return ret;
}

2372 2373 2374 2375 2376 2377 2378
/*
 * 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,
2379
				gfp_t gfp_mask, enum charge_type ctype)
2380
{
2381
	struct mem_cgroup *mem = NULL;
2382
	int page_size = PAGE_SIZE;
2383
	struct page_cgroup *pc;
2384
	bool oom = true;
2385
	int ret;
A
Andrea Arcangeli 已提交
2386

A
Andrea Arcangeli 已提交
2387
	if (PageTransHuge(page)) {
A
Andrea Arcangeli 已提交
2388
		page_size <<= compound_order(page);
A
Andrea Arcangeli 已提交
2389
		VM_BUG_ON(!PageTransHuge(page));
2390 2391 2392 2393 2394
		/*
		 * Never OOM-kill a process for a huge page.  The
		 * fault handler will fall back to regular pages.
		 */
		oom = false;
A
Andrea Arcangeli 已提交
2395
	}
2396 2397 2398 2399 2400 2401 2402

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

2403
	ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, oom, page_size);
2404
	if (ret || !mem)
2405 2406
		return ret;

A
Andrea Arcangeli 已提交
2407
	__mem_cgroup_commit_charge(mem, pc, ctype, page_size);
2408 2409 2410
	return 0;
}

2411 2412
int mem_cgroup_newpage_charge(struct page *page,
			      struct mm_struct *mm, gfp_t gfp_mask)
2413
{
2414
	if (mem_cgroup_disabled())
2415
		return 0;
2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426
	/*
	 * 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;
2427
	return mem_cgroup_charge_common(page, mm, gfp_mask,
2428
				MEM_CGROUP_CHARGE_TYPE_MAPPED);
2429 2430
}

D
Daisuke Nishimura 已提交
2431 2432 2433 2434
static void
__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
					enum charge_type ctype);

2435 2436
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
				gfp_t gfp_mask)
2437
{
2438 2439
	int ret;

2440
	if (mem_cgroup_disabled())
2441
		return 0;
2442 2443
	if (PageCompound(page))
		return 0;
2444 2445 2446 2447 2448 2449 2450 2451
	/*
	 * 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.)
2452 2453
	 * And when the page is SwapCache, it should take swap information
	 * into account. This is under lock_page() now.
2454 2455 2456 2457
	 */
	if (!(gfp_mask & __GFP_WAIT)) {
		struct page_cgroup *pc;

2458 2459 2460 2461 2462 2463
		pc = lookup_page_cgroup(page);
		if (!pc)
			return 0;
		lock_page_cgroup(pc);
		if (PageCgroupUsed(pc)) {
			unlock_page_cgroup(pc);
2464 2465
			return 0;
		}
2466
		unlock_page_cgroup(pc);
2467 2468
	}

2469
	if (unlikely(!mm))
2470
		mm = &init_mm;
2471

2472 2473
	if (page_is_file_cache(page))
		return mem_cgroup_charge_common(page, mm, gfp_mask,
2474
				MEM_CGROUP_CHARGE_TYPE_CACHE);
2475

D
Daisuke Nishimura 已提交
2476 2477
	/* shmem */
	if (PageSwapCache(page)) {
2478 2479
		struct mem_cgroup *mem = NULL;

D
Daisuke Nishimura 已提交
2480 2481 2482 2483 2484 2485
		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,
2486
					MEM_CGROUP_CHARGE_TYPE_SHMEM);
2487 2488

	return ret;
2489 2490
}

2491 2492 2493
/*
 * While swap-in, try_charge -> commit or cancel, the page is locked.
 * And when try_charge() successfully returns, one refcnt to memcg without
2494
 * struct page_cgroup is acquired. This refcnt will be consumed by
2495 2496
 * "commit()" or removed by "cancel()"
 */
2497 2498 2499 2500 2501
int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
				 struct page *page,
				 gfp_t mask, struct mem_cgroup **ptr)
{
	struct mem_cgroup *mem;
2502
	int ret;
2503

2504
	if (mem_cgroup_disabled())
2505 2506 2507 2508 2509 2510
		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
2511 2512 2513
	 * 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.
2514 2515
	 */
	if (!PageSwapCache(page))
H
Hugh Dickins 已提交
2516
		goto charge_cur_mm;
2517
	mem = try_get_mem_cgroup_from_page(page);
2518 2519
	if (!mem)
		goto charge_cur_mm;
2520
	*ptr = mem;
A
Andrea Arcangeli 已提交
2521
	ret = __mem_cgroup_try_charge(NULL, mask, ptr, true, PAGE_SIZE);
2522 2523
	css_put(&mem->css);
	return ret;
2524 2525 2526
charge_cur_mm:
	if (unlikely(!mm))
		mm = &init_mm;
A
Andrea Arcangeli 已提交
2527
	return __mem_cgroup_try_charge(mm, mask, ptr, true, PAGE_SIZE);
2528 2529
}

D
Daisuke Nishimura 已提交
2530 2531 2532
static void
__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
					enum charge_type ctype)
2533 2534 2535
{
	struct page_cgroup *pc;

2536
	if (mem_cgroup_disabled())
2537 2538 2539
		return;
	if (!ptr)
		return;
2540
	cgroup_exclude_rmdir(&ptr->css);
2541
	pc = lookup_page_cgroup(page);
2542
	mem_cgroup_lru_del_before_commit_swapcache(page);
A
Andrea Arcangeli 已提交
2543
	__mem_cgroup_commit_charge(ptr, pc, ctype, PAGE_SIZE);
2544
	mem_cgroup_lru_add_after_commit_swapcache(page);
2545 2546 2547
	/*
	 * Now swap is on-memory. This means this page may be
	 * counted both as mem and swap....double count.
2548 2549 2550
	 * 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.
2551
	 */
2552
	if (do_swap_account && PageSwapCache(page)) {
2553
		swp_entry_t ent = {.val = page_private(page)};
2554
		unsigned short id;
2555
		struct mem_cgroup *memcg;
2556 2557 2558 2559

		id = swap_cgroup_record(ent, 0);
		rcu_read_lock();
		memcg = mem_cgroup_lookup(id);
2560
		if (memcg) {
2561 2562 2563 2564
			/*
			 * This recorded memcg can be obsolete one. So, avoid
			 * calling css_tryget
			 */
2565
			if (!mem_cgroup_is_root(memcg))
2566
				res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2567
			mem_cgroup_swap_statistics(memcg, false);
2568 2569
			mem_cgroup_put(memcg);
		}
2570
		rcu_read_unlock();
2571
	}
2572 2573 2574 2575 2576 2577
	/*
	 * 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);
2578 2579
}

D
Daisuke Nishimura 已提交
2580 2581 2582 2583 2584 2585
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);
}

2586 2587
void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
{
2588
	if (mem_cgroup_disabled())
2589 2590 2591
		return;
	if (!mem)
		return;
A
Andrea Arcangeli 已提交
2592
	mem_cgroup_cancel_charge(mem, PAGE_SIZE);
2593 2594
}

2595
static void
A
Andrea Arcangeli 已提交
2596 2597
__do_uncharge(struct mem_cgroup *mem, const enum charge_type ctype,
	      int page_size)
2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612
{
	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;
2613 2614 2615 2616 2617 2618 2619 2620 2621 2622 2623
	/*
	 * 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
2624 2625 2626
	if (page_size != PAGE_SIZE)
		goto direct_uncharge;

2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639
	/*
	 * 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
2640
	res_counter_uncharge(&mem->res, page_size);
2641
	if (uncharge_memsw)
A
Andrea Arcangeli 已提交
2642
		res_counter_uncharge(&mem->memsw, page_size);
2643 2644
	if (unlikely(batch->memcg != mem))
		memcg_oom_recover(mem);
2645 2646
	return;
}
2647

2648
/*
2649
 * uncharge if !page_mapped(page)
2650
 */
2651
static struct mem_cgroup *
2652
__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
2653
{
2654
	int count;
H
Hugh Dickins 已提交
2655
	struct page_cgroup *pc;
2656
	struct mem_cgroup *mem = NULL;
A
Andrea Arcangeli 已提交
2657
	int page_size = PAGE_SIZE;
2658

2659
	if (mem_cgroup_disabled())
2660
		return NULL;
2661

K
KAMEZAWA Hiroyuki 已提交
2662
	if (PageSwapCache(page))
2663
		return NULL;
K
KAMEZAWA Hiroyuki 已提交
2664

A
Andrea Arcangeli 已提交
2665
	if (PageTransHuge(page)) {
A
Andrea Arcangeli 已提交
2666
		page_size <<= compound_order(page);
A
Andrea Arcangeli 已提交
2667 2668
		VM_BUG_ON(!PageTransHuge(page));
	}
A
Andrea Arcangeli 已提交
2669

2670
	count = page_size >> PAGE_SHIFT;
2671
	/*
2672
	 * Check if our page_cgroup is valid
2673
	 */
2674 2675
	pc = lookup_page_cgroup(page);
	if (unlikely(!pc || !PageCgroupUsed(pc)))
2676
		return NULL;
2677

2678
	lock_page_cgroup(pc);
K
KAMEZAWA Hiroyuki 已提交
2679

2680 2681
	mem = pc->mem_cgroup;

K
KAMEZAWA Hiroyuki 已提交
2682 2683 2684 2685 2686
	if (!PageCgroupUsed(pc))
		goto unlock_out;

	switch (ctype) {
	case MEM_CGROUP_CHARGE_TYPE_MAPPED:
K
KAMEZAWA Hiroyuki 已提交
2687
	case MEM_CGROUP_CHARGE_TYPE_DROP:
2688 2689
		/* See mem_cgroup_prepare_migration() */
		if (page_mapped(page) || PageCgroupMigration(pc))
K
KAMEZAWA Hiroyuki 已提交
2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700
			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;
2701
	}
K
KAMEZAWA Hiroyuki 已提交
2702

2703
	mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), -count);
K
KAMEZAWA Hiroyuki 已提交
2704

2705
	ClearPageCgroupUsed(pc);
2706 2707 2708 2709 2710 2711
	/*
	 * 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.
	 */
2712

2713
	unlock_page_cgroup(pc);
K
KAMEZAWA Hiroyuki 已提交
2714 2715 2716 2717
	/*
	 * even after unlock, we have mem->res.usage here and this memcg
	 * will never be freed.
	 */
2718
	memcg_check_events(mem, page);
K
KAMEZAWA Hiroyuki 已提交
2719 2720 2721 2722 2723
	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
2724
		__do_uncharge(mem, ctype, page_size);
2725

2726
	return mem;
K
KAMEZAWA Hiroyuki 已提交
2727 2728 2729

unlock_out:
	unlock_page_cgroup(pc);
2730
	return NULL;
2731 2732
}

2733 2734
void mem_cgroup_uncharge_page(struct page *page)
{
2735 2736 2737 2738 2739
	/* early check. */
	if (page_mapped(page))
		return;
	if (page->mapping && !PageAnon(page))
		return;
2740 2741 2742 2743 2744 2745
	__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));
2746
	VM_BUG_ON(page->mapping);
2747 2748 2749
	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
}

2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789
/*
 * 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);
2790
	memcg_oom_recover(batch->memcg);
2791 2792 2793 2794
	/* forget this pointer (for sanity check) */
	batch->memcg = NULL;
}

2795
#ifdef CONFIG_SWAP
2796
/*
2797
 * called after __delete_from_swap_cache() and drop "page" account.
2798 2799
 * memcg information is recorded to swap_cgroup of "ent"
 */
K
KAMEZAWA Hiroyuki 已提交
2800 2801
void
mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
2802 2803
{
	struct mem_cgroup *memcg;
K
KAMEZAWA Hiroyuki 已提交
2804 2805 2806 2807 2808 2809
	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);
2810

K
KAMEZAWA Hiroyuki 已提交
2811 2812 2813 2814 2815
	/*
	 * record memcg information,  if swapout && memcg != NULL,
	 * mem_cgroup_get() was called in uncharge().
	 */
	if (do_swap_account && swapout && memcg)
2816
		swap_cgroup_record(ent, css_id(&memcg->css));
2817
}
2818
#endif
2819 2820 2821 2822 2823 2824 2825

#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
2826
{
2827
	struct mem_cgroup *memcg;
2828
	unsigned short id;
2829 2830 2831 2832

	if (!do_swap_account)
		return;

2833 2834 2835
	id = swap_cgroup_record(ent, 0);
	rcu_read_lock();
	memcg = mem_cgroup_lookup(id);
2836
	if (memcg) {
2837 2838 2839 2840
		/*
		 * We uncharge this because swap is freed.
		 * This memcg can be obsolete one. We avoid calling css_tryget
		 */
2841
		if (!mem_cgroup_is_root(memcg))
2842
			res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2843
		mem_cgroup_swap_statistics(memcg, false);
2844 2845
		mem_cgroup_put(memcg);
	}
2846
	rcu_read_unlock();
K
KAMEZAWA Hiroyuki 已提交
2847
}
2848 2849 2850 2851 2852 2853

/**
 * 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
2854
 * @need_fixup: whether we should fixup res_counters and refcounts.
2855 2856 2857 2858 2859 2860 2861 2862 2863 2864
 *
 * 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,
2865
		struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2866 2867 2868 2869 2870 2871 2872 2873
{
	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);
2874
		mem_cgroup_swap_statistics(to, true);
2875
		/*
2876 2877 2878 2879 2880 2881
		 * 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.
2882 2883
		 */
		mem_cgroup_get(to);
2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894
		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);
		}
2895 2896 2897 2898 2899 2900
		return 0;
	}
	return -EINVAL;
}
#else
static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
2901
		struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
2902 2903 2904
{
	return -EINVAL;
}
2905
#endif
K
KAMEZAWA Hiroyuki 已提交
2906

2907
/*
2908 2909
 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
 * page belongs to.
2910
 */
2911
int mem_cgroup_prepare_migration(struct page *page,
2912
	struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask)
2913 2914
{
	struct page_cgroup *pc;
2915
	struct mem_cgroup *mem = NULL;
2916
	enum charge_type ctype;
2917
	int ret = 0;
2918

A
Andrea Arcangeli 已提交
2919
	VM_BUG_ON(PageTransHuge(page));
2920
	if (mem_cgroup_disabled())
2921 2922
		return 0;

2923 2924 2925
	pc = lookup_page_cgroup(page);
	lock_page_cgroup(pc);
	if (PageCgroupUsed(pc)) {
2926 2927
		mem = pc->mem_cgroup;
		css_get(&mem->css);
2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958
		/*
		 * 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);
2959
	}
2960
	unlock_page_cgroup(pc);
2961 2962 2963 2964 2965 2966
	/*
	 * If the page is not charged at this point,
	 * we return here.
	 */
	if (!mem)
		return 0;
2967

A
Andrea Arcangeli 已提交
2968
	*ptr = mem;
2969
	ret = __mem_cgroup_try_charge(NULL, gfp_mask, ptr, false, PAGE_SIZE);
2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981
	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;
2982
	}
2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995
	/*
	 * 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
2996
	__mem_cgroup_commit_charge(mem, pc, ctype, PAGE_SIZE);
2997
	return ret;
2998
}
2999

3000
/* remove redundant charge if migration failed*/
3001
void mem_cgroup_end_migration(struct mem_cgroup *mem,
3002
	struct page *oldpage, struct page *newpage, bool migration_ok)
3003
{
3004
	struct page *used, *unused;
3005 3006 3007 3008
	struct page_cgroup *pc;

	if (!mem)
		return;
3009
	/* blocks rmdir() */
3010
	cgroup_exclude_rmdir(&mem->css);
3011
	if (!migration_ok) {
3012 3013
		used = oldpage;
		unused = newpage;
3014
	} else {
3015
		used = newpage;
3016 3017
		unused = oldpage;
	}
3018
	/*
3019 3020 3021
	 * 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.
3022
	 */
3023 3024 3025 3026
	pc = lookup_page_cgroup(oldpage);
	lock_page_cgroup(pc);
	ClearPageCgroupMigration(pc);
	unlock_page_cgroup(pc);
3027

3028 3029
	__mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);

3030
	/*
3031 3032 3033 3034 3035 3036
	 * 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)
3037
	 */
3038 3039
	if (PageAnon(used))
		mem_cgroup_uncharge_page(used);
3040
	/*
3041 3042
	 * At migration, we may charge account against cgroup which has no
	 * tasks.
3043 3044 3045 3046
	 * 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);
3047
}
3048

3049
/*
3050 3051 3052 3053 3054 3055
 * 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.
3056
 */
3057
int mem_cgroup_shmem_charge_fallback(struct page *page,
3058 3059
			    struct mm_struct *mm,
			    gfp_t gfp_mask)
3060
{
3061
	struct mem_cgroup *mem = NULL;
3062
	int ret;
3063

3064
	if (mem_cgroup_disabled())
3065
		return 0;
3066

3067 3068 3069
	ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
	if (!ret)
		mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
3070

3071
	return ret;
3072 3073
}

3074 3075
static DEFINE_MUTEX(set_limit_mutex);

3076
static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
3077
				unsigned long long val)
3078
{
3079
	int retry_count;
3080
	u64 memswlimit, memlimit;
3081
	int ret = 0;
3082 3083
	int children = mem_cgroup_count_children(memcg);
	u64 curusage, oldusage;
3084
	int enlarge;
3085 3086 3087 3088 3089 3090 3091 3092 3093

	/*
	 * 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);
3094

3095
	enlarge = 0;
3096
	while (retry_count) {
3097 3098 3099 3100
		if (signal_pending(current)) {
			ret = -EINTR;
			break;
		}
3101 3102 3103 3104 3105 3106 3107 3108 3109 3110
		/*
		 * 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);
3111 3112
			break;
		}
3113 3114 3115 3116 3117

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

3118
		ret = res_counter_set_limit(&memcg->res, val);
3119 3120 3121 3122 3123 3124
		if (!ret) {
			if (memswlimit == val)
				memcg->memsw_is_minimum = true;
			else
				memcg->memsw_is_minimum = false;
		}
3125 3126 3127 3128 3129
		mutex_unlock(&set_limit_mutex);

		if (!ret)
			break;

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

3142 3143 3144
	return ret;
}

L
Li Zefan 已提交
3145 3146
static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
					unsigned long long val)
3147
{
3148
	int retry_count;
3149
	u64 memlimit, memswlimit, oldusage, curusage;
3150 3151
	int children = mem_cgroup_count_children(memcg);
	int ret = -EBUSY;
3152
	int enlarge = 0;
3153

3154 3155 3156
	/* see mem_cgroup_resize_res_limit */
 	retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
	oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173
	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;
		}
3174 3175 3176
		memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
		if (memswlimit < val)
			enlarge = 1;
3177
		ret = res_counter_set_limit(&memcg->memsw, val);
3178 3179 3180 3181 3182 3183
		if (!ret) {
			if (memlimit == val)
				memcg->memsw_is_minimum = true;
			else
				memcg->memsw_is_minimum = false;
		}
3184 3185 3186 3187 3188
		mutex_unlock(&set_limit_mutex);

		if (!ret)
			break;

3189
		mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3190 3191
						MEM_CGROUP_RECLAIM_NOSWAP |
						MEM_CGROUP_RECLAIM_SHRINK);
3192
		curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3193
		/* Usage is reduced ? */
3194
		if (curusage >= oldusage)
3195
			retry_count--;
3196 3197
		else
			oldusage = curusage;
3198
	}
3199 3200
	if (!ret && enlarge)
		memcg_oom_recover(memcg);
3201 3202 3203
	return ret;
}

3204
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3205
					    gfp_t gfp_mask)
3206 3207 3208 3209 3210 3211
{
	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;
3212
	unsigned long long excess;
3213 3214 3215 3216

	if (order > 0)
		return 0;

3217
	mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264
	/*
	 * 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);
3265
		excess = res_counter_soft_limit_excess(&mz->mem->res);
3266 3267 3268 3269 3270 3271 3272 3273
		/*
		 * 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.
		 */
3274 3275
		/* If excess == 0, no tree ops */
		__mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess);
3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 3293
		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;
}

3294 3295 3296 3297
/*
 * This routine traverse page_cgroup in given list and drop them all.
 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
 */
3298
static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
K
KAMEZAWA Hiroyuki 已提交
3299
				int node, int zid, enum lru_list lru)
3300
{
K
KAMEZAWA Hiroyuki 已提交
3301 3302
	struct zone *zone;
	struct mem_cgroup_per_zone *mz;
3303
	struct page_cgroup *pc, *busy;
K
KAMEZAWA Hiroyuki 已提交
3304
	unsigned long flags, loop;
3305
	struct list_head *list;
3306
	int ret = 0;
3307

K
KAMEZAWA Hiroyuki 已提交
3308 3309
	zone = &NODE_DATA(node)->node_zones[zid];
	mz = mem_cgroup_zoneinfo(mem, node, zid);
3310
	list = &mz->lists[lru];
3311

3312 3313 3314 3315 3316 3317
	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
3318
		spin_lock_irqsave(&zone->lru_lock, flags);
3319
		if (list_empty(list)) {
K
KAMEZAWA Hiroyuki 已提交
3320
			spin_unlock_irqrestore(&zone->lru_lock, flags);
3321
			break;
3322 3323 3324 3325
		}
		pc = list_entry(list->prev, struct page_cgroup, lru);
		if (busy == pc) {
			list_move(&pc->lru, list);
3326
			busy = NULL;
K
KAMEZAWA Hiroyuki 已提交
3327
			spin_unlock_irqrestore(&zone->lru_lock, flags);
3328 3329
			continue;
		}
K
KAMEZAWA Hiroyuki 已提交
3330
		spin_unlock_irqrestore(&zone->lru_lock, flags);
3331

K
KAMEZAWA Hiroyuki 已提交
3332
		ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL);
3333
		if (ret == -ENOMEM)
3334
			break;
3335 3336 3337 3338 3339 3340 3341

		if (ret == -EBUSY || ret == -EINVAL) {
			/* found lock contention or "pc" is obsolete. */
			busy = pc;
			cond_resched();
		} else
			busy = NULL;
3342
	}
K
KAMEZAWA Hiroyuki 已提交
3343

3344 3345 3346
	if (!ret && !list_empty(list))
		return -EBUSY;
	return ret;
3347 3348 3349 3350 3351 3352
}

/*
 * make mem_cgroup's charge to be 0 if there is no task.
 * This enables deleting this mem_cgroup.
 */
3353
static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
3354
{
3355 3356 3357
	int ret;
	int node, zid, shrink;
	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3358
	struct cgroup *cgrp = mem->css.cgroup;
3359

3360
	css_get(&mem->css);
3361 3362

	shrink = 0;
3363 3364 3365
	/* should free all ? */
	if (free_all)
		goto try_to_free;
3366
move_account:
3367
	do {
3368
		ret = -EBUSY;
3369 3370 3371 3372
		if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
			goto out;
		ret = -EINTR;
		if (signal_pending(current))
3373
			goto out;
3374 3375
		/* This is for making all *used* pages to be on LRU. */
		lru_add_drain_all();
3376
		drain_all_stock_sync();
3377
		ret = 0;
3378
		mem_cgroup_start_move(mem);
3379
		for_each_node_state(node, N_HIGH_MEMORY) {
3380
			for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
3381
				enum lru_list l;
3382 3383
				for_each_lru(l) {
					ret = mem_cgroup_force_empty_list(mem,
K
KAMEZAWA Hiroyuki 已提交
3384
							node, zid, l);
3385 3386 3387
					if (ret)
						break;
				}
3388
			}
3389 3390 3391
			if (ret)
				break;
		}
3392
		mem_cgroup_end_move(mem);
3393
		memcg_oom_recover(mem);
3394 3395 3396
		/* it seems parent cgroup doesn't have enough mem */
		if (ret == -ENOMEM)
			goto try_to_free;
3397
		cond_resched();
3398 3399
	/* "ret" should also be checked to ensure all lists are empty. */
	} while (mem->res.usage > 0 || ret);
3400 3401 3402
out:
	css_put(&mem->css);
	return ret;
3403 3404

try_to_free:
3405 3406
	/* returns EBUSY if there is a task or if we come here twice. */
	if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
3407 3408 3409
		ret = -EBUSY;
		goto out;
	}
3410 3411
	/* we call try-to-free pages for make this cgroup empty */
	lru_add_drain_all();
3412 3413 3414 3415
	/* try to free all pages in this cgroup */
	shrink = 1;
	while (nr_retries && mem->res.usage > 0) {
		int progress;
3416 3417 3418 3419 3420

		if (signal_pending(current)) {
			ret = -EINTR;
			goto out;
		}
K
KOSAKI Motohiro 已提交
3421 3422
		progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
						false, get_swappiness(mem));
3423
		if (!progress) {
3424
			nr_retries--;
3425
			/* maybe some writeback is necessary */
3426
			congestion_wait(BLK_RW_ASYNC, HZ/10);
3427
		}
3428 3429

	}
K
KAMEZAWA Hiroyuki 已提交
3430
	lru_add_drain();
3431
	/* try move_account...there may be some *locked* pages. */
3432
	goto move_account;
3433 3434
}

3435 3436 3437 3438 3439 3440
int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
{
	return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
}


3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453 3454 3455 3456 3457 3458
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();
	/*
3459
	 * If parent's use_hierarchy is set, we can't make any modifications
3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478
	 * 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;
}

3479

K
KAMEZAWA Hiroyuki 已提交
3480 3481
static u64 mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem,
				enum mem_cgroup_stat_index idx)
3482
{
K
KAMEZAWA Hiroyuki 已提交
3483 3484
	struct mem_cgroup *iter;
	s64 val = 0;
3485

K
KAMEZAWA Hiroyuki 已提交
3486 3487 3488 3489 3490 3491 3492
	/* 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;
3493 3494
}

3495 3496
static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap)
{
K
KAMEZAWA Hiroyuki 已提交
3497
	u64 val;
3498 3499 3500 3501 3502 3503 3504 3505

	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
3506 3507
	val = mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_CACHE);
	val += mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_RSS);
3508

K
KAMEZAWA Hiroyuki 已提交
3509 3510 3511
	if (swap)
		val += mem_cgroup_get_recursive_idx_stat(mem,
				MEM_CGROUP_STAT_SWAPOUT);
3512 3513 3514 3515

	return val << PAGE_SHIFT;
}

3516
static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
B
Balbir Singh 已提交
3517
{
3518
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3519
	u64 val;
3520 3521 3522 3523 3524 3525
	int type, name;

	type = MEMFILE_TYPE(cft->private);
	name = MEMFILE_ATTR(cft->private);
	switch (type) {
	case _MEM:
3526 3527 3528
		if (name == RES_USAGE)
			val = mem_cgroup_usage(mem, false);
		else
3529
			val = res_counter_read_u64(&mem->res, name);
3530 3531
		break;
	case _MEMSWAP:
3532 3533 3534
		if (name == RES_USAGE)
			val = mem_cgroup_usage(mem, true);
		else
3535
			val = res_counter_read_u64(&mem->memsw, name);
3536 3537 3538 3539 3540 3541
		break;
	default:
		BUG();
		break;
	}
	return val;
B
Balbir Singh 已提交
3542
}
3543 3544 3545 3546
/*
 * The user of this function is...
 * RES_LIMIT.
 */
3547 3548
static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
			    const char *buffer)
B
Balbir Singh 已提交
3549
{
3550
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3551
	int type, name;
3552 3553 3554
	unsigned long long val;
	int ret;

3555 3556 3557
	type = MEMFILE_TYPE(cft->private);
	name = MEMFILE_ATTR(cft->private);
	switch (name) {
3558
	case RES_LIMIT:
3559 3560 3561 3562
		if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
			ret = -EINVAL;
			break;
		}
3563 3564
		/* This function does all necessary parse...reuse it */
		ret = res_counter_memparse_write_strategy(buffer, &val);
3565 3566 3567
		if (ret)
			break;
		if (type == _MEM)
3568
			ret = mem_cgroup_resize_limit(memcg, val);
3569 3570
		else
			ret = mem_cgroup_resize_memsw_limit(memcg, val);
3571
		break;
3572 3573 3574 3575 3576 3577 3578 3579 3580 3581 3582 3583 3584 3585
	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;
3586 3587 3588 3589 3590
	default:
		ret = -EINVAL; /* should be BUG() ? */
		break;
	}
	return ret;
B
Balbir Singh 已提交
3591 3592
}

3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620
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;
}

3621
static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
3622 3623
{
	struct mem_cgroup *mem;
3624
	int type, name;
3625 3626

	mem = mem_cgroup_from_cont(cont);
3627 3628 3629
	type = MEMFILE_TYPE(event);
	name = MEMFILE_ATTR(event);
	switch (name) {
3630
	case RES_MAX_USAGE:
3631 3632 3633 3634
		if (type == _MEM)
			res_counter_reset_max(&mem->res);
		else
			res_counter_reset_max(&mem->memsw);
3635 3636
		break;
	case RES_FAILCNT:
3637 3638 3639 3640
		if (type == _MEM)
			res_counter_reset_failcnt(&mem->res);
		else
			res_counter_reset_failcnt(&mem->memsw);
3641 3642
		break;
	}
3643

3644
	return 0;
3645 3646
}

3647 3648 3649 3650 3651 3652
static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
					struct cftype *cft)
{
	return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
}

3653
#ifdef CONFIG_MMU
3654 3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671
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;
}
3672 3673 3674 3675 3676 3677 3678
#else
static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
					struct cftype *cft, u64 val)
{
	return -ENOSYS;
}
#endif
3679

K
KAMEZAWA Hiroyuki 已提交
3680 3681 3682 3683 3684

/* For read statistics */
enum {
	MCS_CACHE,
	MCS_RSS,
3685
	MCS_FILE_MAPPED,
K
KAMEZAWA Hiroyuki 已提交
3686 3687
	MCS_PGPGIN,
	MCS_PGPGOUT,
3688
	MCS_SWAP,
K
KAMEZAWA Hiroyuki 已提交
3689 3690 3691 3692 3693 3694 3695 3696 3697 3698
	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];
3699 3700
};

K
KAMEZAWA Hiroyuki 已提交
3701 3702 3703 3704 3705 3706
struct {
	char *local_name;
	char *total_name;
} memcg_stat_strings[NR_MCS_STAT] = {
	{"cache", "total_cache"},
	{"rss", "total_rss"},
3707
	{"mapped_file", "total_mapped_file"},
K
KAMEZAWA Hiroyuki 已提交
3708 3709
	{"pgpgin", "total_pgpgin"},
	{"pgpgout", "total_pgpgout"},
3710
	{"swap", "total_swap"},
K
KAMEZAWA Hiroyuki 已提交
3711 3712 3713 3714 3715 3716 3717 3718
	{"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
3719 3720
static void
mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
K
KAMEZAWA Hiroyuki 已提交
3721 3722 3723 3724
{
	s64 val;

	/* per cpu stat */
3725
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
K
KAMEZAWA Hiroyuki 已提交
3726
	s->stat[MCS_CACHE] += val * PAGE_SIZE;
3727
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
K
KAMEZAWA Hiroyuki 已提交
3728
	s->stat[MCS_RSS] += val * PAGE_SIZE;
3729
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED);
3730
	s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
3731
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGIN_COUNT);
K
KAMEZAWA Hiroyuki 已提交
3732
	s->stat[MCS_PGPGIN] += val;
3733
	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGOUT_COUNT);
K
KAMEZAWA Hiroyuki 已提交
3734
	s->stat[MCS_PGPGOUT] += val;
3735
	if (do_swap_account) {
3736
		val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
3737 3738
		s->stat[MCS_SWAP] += val * PAGE_SIZE;
	}
K
KAMEZAWA Hiroyuki 已提交
3739 3740 3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755

	/* 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
3756 3757 3758 3759
	struct mem_cgroup *iter;

	for_each_mem_cgroup_tree(iter, mem)
		mem_cgroup_get_local_stat(iter, s);
K
KAMEZAWA Hiroyuki 已提交
3760 3761
}

3762 3763
static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
				 struct cgroup_map_cb *cb)
3764 3765
{
	struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
K
KAMEZAWA Hiroyuki 已提交
3766
	struct mcs_total_stat mystat;
3767 3768
	int i;

K
KAMEZAWA Hiroyuki 已提交
3769 3770
	memset(&mystat, 0, sizeof(mystat));
	mem_cgroup_get_local_stat(mem_cont, &mystat);
3771

3772 3773 3774
	for (i = 0; i < NR_MCS_STAT; i++) {
		if (i == MCS_SWAP && !do_swap_account)
			continue;
K
KAMEZAWA Hiroyuki 已提交
3775
		cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
3776
	}
L
Lee Schermerhorn 已提交
3777

K
KAMEZAWA Hiroyuki 已提交
3778
	/* Hierarchical information */
3779 3780 3781 3782 3783 3784 3785
	{
		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
3786

K
KAMEZAWA Hiroyuki 已提交
3787 3788
	memset(&mystat, 0, sizeof(mystat));
	mem_cgroup_get_total_stat(mem_cont, &mystat);
3789 3790 3791
	for (i = 0; i < NR_MCS_STAT; i++) {
		if (i == MCS_SWAP && !do_swap_account)
			continue;
K
KAMEZAWA Hiroyuki 已提交
3792
		cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
3793
	}
K
KAMEZAWA Hiroyuki 已提交
3794

K
KOSAKI Motohiro 已提交
3795
#ifdef CONFIG_DEBUG_VM
3796
	cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
K
KOSAKI Motohiro 已提交
3797 3798 3799 3800 3801 3802 3803 3804 3805 3806 3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823

	{
		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

3824 3825 3826
	return 0;
}

K
KOSAKI Motohiro 已提交
3827 3828 3829 3830 3831 3832 3833 3834 3835 3836 3837 3838
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;
3839

K
KOSAKI Motohiro 已提交
3840 3841 3842 3843 3844 3845 3846
	if (val > 100)
		return -EINVAL;

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

	parent = mem_cgroup_from_cont(cgrp->parent);
3847 3848 3849

	cgroup_lock();

K
KOSAKI Motohiro 已提交
3850 3851
	/* If under hierarchy, only empty-root can set this value */
	if ((parent->use_hierarchy) ||
3852 3853
	    (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
		cgroup_unlock();
K
KOSAKI Motohiro 已提交
3854
		return -EINVAL;
3855
	}
K
KOSAKI Motohiro 已提交
3856 3857 3858 3859 3860

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

3861 3862
	cgroup_unlock();

K
KOSAKI Motohiro 已提交
3863 3864 3865
	return 0;
}

3866 3867 3868 3869 3870 3871 3872 3873
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)
3874
		t = rcu_dereference(memcg->thresholds.primary);
3875
	else
3876
		t = rcu_dereference(memcg->memsw_thresholds.primary);
3877 3878 3879 3880 3881 3882 3883 3884 3885 3886 3887

	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().
	 */
3888
	i = t->current_threshold;
3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911

	/*
	 * 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 */
3912
	t->current_threshold = i - 1;
3913 3914 3915 3916 3917 3918
unlock:
	rcu_read_unlock();
}

static void mem_cgroup_threshold(struct mem_cgroup *memcg)
{
3919 3920 3921 3922 3923 3924 3925
	while (memcg) {
		__mem_cgroup_threshold(memcg, false);
		if (do_swap_account)
			__mem_cgroup_threshold(memcg, true);

		memcg = parent_mem_cgroup(memcg);
	}
3926 3927 3928 3929 3930 3931 3932 3933 3934 3935
}

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
3936
static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem)
K
KAMEZAWA Hiroyuki 已提交
3937 3938 3939 3940 3941 3942 3943 3944 3945 3946
{
	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
3947 3948 3949 3950
	struct mem_cgroup *iter;

	for_each_mem_cgroup_tree(iter, mem)
		mem_cgroup_oom_notify_cb(iter);
K
KAMEZAWA Hiroyuki 已提交
3951 3952 3953 3954
}

static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
	struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
3955 3956
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3957 3958
	struct mem_cgroup_thresholds *thresholds;
	struct mem_cgroup_threshold_ary *new;
3959 3960
	int type = MEMFILE_TYPE(cft->private);
	u64 threshold, usage;
3961
	int i, size, ret;
3962 3963 3964 3965 3966 3967

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

	mutex_lock(&memcg->thresholds_lock);
3968

3969
	if (type == _MEM)
3970
		thresholds = &memcg->thresholds;
3971
	else if (type == _MEMSWAP)
3972
		thresholds = &memcg->memsw_thresholds;
3973 3974 3975 3976 3977 3978
	else
		BUG();

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

	/* Check if a threshold crossed before adding a new one */
3979
	if (thresholds->primary)
3980 3981
		__mem_cgroup_threshold(memcg, type == _MEMSWAP);

3982
	size = thresholds->primary ? thresholds->primary->size + 1 : 1;
3983 3984

	/* Allocate memory for new array of thresholds */
3985
	new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
3986
			GFP_KERNEL);
3987
	if (!new) {
3988 3989 3990
		ret = -ENOMEM;
		goto unlock;
	}
3991
	new->size = size;
3992 3993

	/* Copy thresholds (if any) to new array */
3994 3995
	if (thresholds->primary) {
		memcpy(new->entries, thresholds->primary->entries, (size - 1) *
3996
				sizeof(struct mem_cgroup_threshold));
3997 3998
	}

3999
	/* Add new threshold */
4000 4001
	new->entries[size - 1].eventfd = eventfd;
	new->entries[size - 1].threshold = threshold;
4002 4003

	/* Sort thresholds. Registering of new threshold isn't time-critical */
4004
	sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
4005 4006 4007
			compare_thresholds, NULL);

	/* Find current threshold */
4008
	new->current_threshold = -1;
4009
	for (i = 0; i < size; i++) {
4010
		if (new->entries[i].threshold < usage) {
4011
			/*
4012 4013
			 * new->current_threshold will not be used until
			 * rcu_assign_pointer(), so it's safe to increment
4014 4015
			 * it here.
			 */
4016
			++new->current_threshold;
4017 4018 4019
		}
	}

4020 4021 4022 4023 4024
	/* Free old spare buffer and save old primary buffer as spare */
	kfree(thresholds->spare);
	thresholds->spare = thresholds->primary;

	rcu_assign_pointer(thresholds->primary, new);
4025

4026
	/* To be sure that nobody uses thresholds */
4027 4028 4029 4030 4031 4032 4033 4034
	synchronize_rcu();

unlock:
	mutex_unlock(&memcg->thresholds_lock);

	return ret;
}

4035
static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
K
KAMEZAWA Hiroyuki 已提交
4036
	struct cftype *cft, struct eventfd_ctx *eventfd)
4037 4038
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4039 4040
	struct mem_cgroup_thresholds *thresholds;
	struct mem_cgroup_threshold_ary *new;
4041 4042
	int type = MEMFILE_TYPE(cft->private);
	u64 usage;
4043
	int i, j, size;
4044 4045 4046

	mutex_lock(&memcg->thresholds_lock);
	if (type == _MEM)
4047
		thresholds = &memcg->thresholds;
4048
	else if (type == _MEMSWAP)
4049
		thresholds = &memcg->memsw_thresholds;
4050 4051 4052 4053 4054 4055 4056 4057 4058 4059 4060 4061 4062 4063 4064
	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 */
4065 4066 4067
	size = 0;
	for (i = 0; i < thresholds->primary->size; i++) {
		if (thresholds->primary->entries[i].eventfd != eventfd)
4068 4069 4070
			size++;
	}

4071
	new = thresholds->spare;
4072

4073 4074
	/* Set thresholds array to NULL if we don't have thresholds */
	if (!size) {
4075 4076
		kfree(new);
		new = NULL;
4077
		goto swap_buffers;
4078 4079
	}

4080
	new->size = size;
4081 4082

	/* Copy thresholds and find current threshold */
4083 4084 4085
	new->current_threshold = -1;
	for (i = 0, j = 0; i < thresholds->primary->size; i++) {
		if (thresholds->primary->entries[i].eventfd == eventfd)
4086 4087
			continue;

4088 4089
		new->entries[j] = thresholds->primary->entries[i];
		if (new->entries[j].threshold < usage) {
4090
			/*
4091
			 * new->current_threshold will not be used
4092 4093 4094
			 * until rcu_assign_pointer(), so it's safe to increment
			 * it here.
			 */
4095
			++new->current_threshold;
4096 4097 4098 4099
		}
		j++;
	}

4100
swap_buffers:
4101 4102 4103
	/* Swap primary and spare array */
	thresholds->spare = thresholds->primary;
	rcu_assign_pointer(thresholds->primary, new);
4104

4105
	/* To be sure that nobody uses thresholds */
4106 4107 4108 4109
	synchronize_rcu();

	mutex_unlock(&memcg->thresholds_lock);
}
4110

K
KAMEZAWA Hiroyuki 已提交
4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128 4129 4130 4131 4132 4133 4134 4135
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;
}

4136
static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
K
KAMEZAWA Hiroyuki 已提交
4137 4138 4139 4140 4141 4142 4143 4144 4145 4146 4147 4148 4149 4150 4151 4152 4153 4154 4155 4156
	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);
}

4157 4158 4159 4160 4161 4162 4163 4164 4165 4166 4167 4168 4169 4170 4171 4172 4173 4174 4175 4176 4177 4178 4179 4180 4181 4182 4183 4184 4185 4186 4187 4188 4189 4190
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;
4191 4192
	if (!val)
		memcg_oom_recover(mem);
4193 4194 4195 4196
	cgroup_unlock();
	return 0;
}

B
Balbir Singh 已提交
4197 4198
static struct cftype mem_cgroup_files[] = {
	{
4199
		.name = "usage_in_bytes",
4200
		.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4201
		.read_u64 = mem_cgroup_read,
K
KAMEZAWA Hiroyuki 已提交
4202 4203
		.register_event = mem_cgroup_usage_register_event,
		.unregister_event = mem_cgroup_usage_unregister_event,
B
Balbir Singh 已提交
4204
	},
4205 4206
	{
		.name = "max_usage_in_bytes",
4207
		.private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4208
		.trigger = mem_cgroup_reset,
4209 4210
		.read_u64 = mem_cgroup_read,
	},
B
Balbir Singh 已提交
4211
	{
4212
		.name = "limit_in_bytes",
4213
		.private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4214
		.write_string = mem_cgroup_write,
4215
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
4216
	},
4217 4218 4219 4220 4221 4222
	{
		.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
4223 4224
	{
		.name = "failcnt",
4225
		.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4226
		.trigger = mem_cgroup_reset,
4227
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
4228
	},
4229 4230
	{
		.name = "stat",
4231
		.read_map = mem_control_stat_show,
4232
	},
4233 4234 4235 4236
	{
		.name = "force_empty",
		.trigger = mem_cgroup_force_empty_write,
	},
4237 4238 4239 4240 4241
	{
		.name = "use_hierarchy",
		.write_u64 = mem_cgroup_hierarchy_write,
		.read_u64 = mem_cgroup_hierarchy_read,
	},
K
KOSAKI Motohiro 已提交
4242 4243 4244 4245 4246
	{
		.name = "swappiness",
		.read_u64 = mem_cgroup_swappiness_read,
		.write_u64 = mem_cgroup_swappiness_write,
	},
4247 4248 4249 4250 4251
	{
		.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
4252 4253
	{
		.name = "oom_control",
4254 4255
		.read_map = mem_cgroup_oom_control_read,
		.write_u64 = mem_cgroup_oom_control_write,
K
KAMEZAWA Hiroyuki 已提交
4256 4257 4258 4259
		.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
4260 4261
};

4262 4263 4264 4265 4266 4267
#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
4268 4269
		.register_event = mem_cgroup_usage_register_event,
		.unregister_event = mem_cgroup_usage_unregister_event,
4270 4271 4272 4273 4274 4275 4276 4277 4278 4279 4280 4281 4282 4283 4284 4285 4286 4287 4288 4289 4290 4291 4292 4293 4294 4295 4296 4297 4298 4299 4300 4301 4302 4303 4304
	},
	{
		.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

4305 4306 4307
static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
	struct mem_cgroup_per_node *pn;
4308
	struct mem_cgroup_per_zone *mz;
4309
	enum lru_list l;
4310
	int zone, tmp = node;
4311 4312 4313 4314 4315 4316 4317 4318
	/*
	 * 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.
	 */
4319 4320
	if (!node_state(node, N_NORMAL_MEMORY))
		tmp = -1;
4321
	pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4322 4323
	if (!pn)
		return 1;
4324

4325
	mem->info.nodeinfo[node] = pn;
4326 4327
	for (zone = 0; zone < MAX_NR_ZONES; zone++) {
		mz = &pn->zoneinfo[zone];
4328 4329
		for_each_lru(l)
			INIT_LIST_HEAD(&mz->lists[l]);
4330
		mz->usage_in_excess = 0;
4331 4332
		mz->on_tree = false;
		mz->mem = mem;
4333
	}
4334 4335 4336
	return 0;
}

4337 4338 4339 4340 4341
static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
	kfree(mem->info.nodeinfo[node]);
}

4342 4343 4344
static struct mem_cgroup *mem_cgroup_alloc(void)
{
	struct mem_cgroup *mem;
4345
	int size = sizeof(struct mem_cgroup);
4346

4347
	/* Can be very big if MAX_NUMNODES is very big */
4348
	if (size < PAGE_SIZE)
4349
		mem = kzalloc(size, GFP_KERNEL);
4350
	else
4351
		mem = vzalloc(size);
4352

4353 4354 4355
	if (!mem)
		return NULL;

4356
	mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4357 4358
	if (!mem->stat)
		goto out_free;
4359
	spin_lock_init(&mem->pcp_counter_lock);
4360
	return mem;
4361 4362 4363 4364 4365 4366 4367

out_free:
	if (size < PAGE_SIZE)
		kfree(mem);
	else
		vfree(mem);
	return NULL;
4368 4369
}

4370 4371 4372 4373 4374 4375 4376 4377 4378 4379 4380
/*
 * 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.
 */

4381
static void __mem_cgroup_free(struct mem_cgroup *mem)
4382
{
K
KAMEZAWA Hiroyuki 已提交
4383 4384
	int node;

4385
	mem_cgroup_remove_from_trees(mem);
K
KAMEZAWA Hiroyuki 已提交
4386 4387
	free_css_id(&mem_cgroup_subsys, &mem->css);

K
KAMEZAWA Hiroyuki 已提交
4388 4389 4390
	for_each_node_state(node, N_POSSIBLE)
		free_mem_cgroup_per_zone_info(mem, node);

4391 4392
	free_percpu(mem->stat);
	if (sizeof(struct mem_cgroup) < PAGE_SIZE)
4393 4394 4395 4396 4397
		kfree(mem);
	else
		vfree(mem);
}

4398 4399 4400 4401 4402
static void mem_cgroup_get(struct mem_cgroup *mem)
{
	atomic_inc(&mem->refcnt);
}

4403
static void __mem_cgroup_put(struct mem_cgroup *mem, int count)
4404
{
4405
	if (atomic_sub_and_test(count, &mem->refcnt)) {
4406
		struct mem_cgroup *parent = parent_mem_cgroup(mem);
4407
		__mem_cgroup_free(mem);
4408 4409 4410
		if (parent)
			mem_cgroup_put(parent);
	}
4411 4412
}

4413 4414 4415 4416 4417
static void mem_cgroup_put(struct mem_cgroup *mem)
{
	__mem_cgroup_put(mem, 1);
}

4418 4419 4420 4421 4422 4423 4424 4425 4426
/*
 * 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);
}
4427

4428 4429 4430
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
static void __init enable_swap_cgroup(void)
{
4431
	if (!mem_cgroup_disabled() && really_do_swap_account)
4432 4433 4434 4435 4436 4437 4438 4439
		do_swap_account = 1;
}
#else
static void __init enable_swap_cgroup(void)
{
}
#endif

4440 4441 4442 4443 4444 4445 4446 4447 4448 4449 4450 4451 4452 4453 4454 4455 4456 4457 4458 4459 4460 4461 4462 4463 4464
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
4465
static struct cgroup_subsys_state * __ref
B
Balbir Singh 已提交
4466 4467
mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
{
4468
	struct mem_cgroup *mem, *parent;
K
KAMEZAWA Hiroyuki 已提交
4469
	long error = -ENOMEM;
4470
	int node;
B
Balbir Singh 已提交
4471

4472 4473
	mem = mem_cgroup_alloc();
	if (!mem)
K
KAMEZAWA Hiroyuki 已提交
4474
		return ERR_PTR(error);
4475

4476 4477 4478
	for_each_node_state(node, N_POSSIBLE)
		if (alloc_mem_cgroup_per_zone_info(mem, node))
			goto free_out;
4479

4480
	/* root ? */
4481
	if (cont->parent == NULL) {
4482
		int cpu;
4483
		enable_swap_cgroup();
4484
		parent = NULL;
4485
		root_mem_cgroup = mem;
4486 4487
		if (mem_cgroup_soft_limit_tree_init())
			goto free_out;
4488 4489 4490 4491 4492
		for_each_possible_cpu(cpu) {
			struct memcg_stock_pcp *stock =
						&per_cpu(memcg_stock, cpu);
			INIT_WORK(&stock->work, drain_local_stock);
		}
4493
		hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
4494
	} else {
4495
		parent = mem_cgroup_from_cont(cont->parent);
4496
		mem->use_hierarchy = parent->use_hierarchy;
4497
		mem->oom_kill_disable = parent->oom_kill_disable;
4498
	}
4499

4500 4501 4502
	if (parent && parent->use_hierarchy) {
		res_counter_init(&mem->res, &parent->res);
		res_counter_init(&mem->memsw, &parent->memsw);
4503 4504 4505 4506 4507 4508 4509
		/*
		 * 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);
4510 4511 4512 4513
	} else {
		res_counter_init(&mem->res, NULL);
		res_counter_init(&mem->memsw, NULL);
	}
K
KAMEZAWA Hiroyuki 已提交
4514
	mem->last_scanned_child = 0;
K
KOSAKI Motohiro 已提交
4515
	spin_lock_init(&mem->reclaim_param_lock);
K
KAMEZAWA Hiroyuki 已提交
4516
	INIT_LIST_HEAD(&mem->oom_notify);
4517

K
KOSAKI Motohiro 已提交
4518 4519
	if (parent)
		mem->swappiness = get_swappiness(parent);
4520
	atomic_set(&mem->refcnt, 1);
4521
	mem->move_charge_at_immigrate = 0;
4522
	mutex_init(&mem->thresholds_lock);
B
Balbir Singh 已提交
4523
	return &mem->css;
4524
free_out:
4525
	__mem_cgroup_free(mem);
4526
	root_mem_cgroup = NULL;
K
KAMEZAWA Hiroyuki 已提交
4527
	return ERR_PTR(error);
B
Balbir Singh 已提交
4528 4529
}

4530
static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
4531 4532 4533
					struct cgroup *cont)
{
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4534 4535

	return mem_cgroup_force_empty(mem, false);
4536 4537
}

B
Balbir Singh 已提交
4538 4539 4540
static void mem_cgroup_destroy(struct cgroup_subsys *ss,
				struct cgroup *cont)
{
4541 4542 4543
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);

	mem_cgroup_put(mem);
B
Balbir Singh 已提交
4544 4545 4546 4547 4548
}

static int mem_cgroup_populate(struct cgroup_subsys *ss,
				struct cgroup *cont)
{
4549 4550 4551 4552 4553 4554 4555 4556
	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
4557 4558
}

4559
#ifdef CONFIG_MMU
4560
/* Handlers for move charge at task migration. */
4561 4562
#define PRECHARGE_COUNT_AT_ONCE	256
static int mem_cgroup_do_precharge(unsigned long count)
4563
{
4564 4565
	int ret = 0;
	int batch_count = PRECHARGE_COUNT_AT_ONCE;
4566 4567
	struct mem_cgroup *mem = mc.to;

4568 4569 4570 4571 4572 4573 4574 4575 4576 4577 4578 4579 4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590 4591 4592 4593 4594 4595 4596 4597 4598 4599 4600 4601 4602
	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
4603 4604
		ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false,
					      PAGE_SIZE);
4605 4606 4607 4608 4609
		if (ret || !mem)
			/* mem_cgroup_clear_mc() will do uncharge later */
			return -ENOMEM;
		mc.precharge++;
	}
4610 4611 4612 4613 4614 4615 4616 4617
	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
4618
 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4619 4620 4621 4622 4623 4624
 *
 * 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).
4625 4626 4627
 *   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.
4628 4629 4630 4631 4632
 *
 * Called with pte lock held.
 */
union mc_target {
	struct page	*page;
4633
	swp_entry_t	ent;
4634 4635 4636 4637 4638
};

enum mc_target_type {
	MC_TARGET_NONE,	/* not used */
	MC_TARGET_PAGE,
4639
	MC_TARGET_SWAP,
4640 4641
};

D
Daisuke Nishimura 已提交
4642 4643
static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
						unsigned long addr, pte_t ptent)
4644
{
D
Daisuke Nishimura 已提交
4645
	struct page *page = vm_normal_page(vma, addr, ptent);
4646

D
Daisuke Nishimura 已提交
4647 4648 4649 4650 4651 4652
	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;
4653 4654
	} else if (!move_file())
		/* we ignore mapcount for file pages */
D
Daisuke Nishimura 已提交
4655 4656 4657 4658 4659 4660 4661 4662 4663 4664 4665 4666 4667 4668 4669 4670 4671 4672
		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 */
4673 4674
		if (page)
			put_page(page);
D
Daisuke Nishimura 已提交
4675
		return NULL;
4676
	}
D
Daisuke Nishimura 已提交
4677 4678 4679 4680 4681 4682
	if (do_swap_account)
		entry->val = ent.val;

	return page;
}

4683 4684 4685 4686 4687 4688 4689 4690 4691 4692 4693 4694 4695 4696 4697 4698 4699 4700 4701 4702 4703 4704 4705 4706 4707 4708 4709 4710 4711 4712 4713 4714 4715
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
4716 4717 4718 4719 4720 4721 4722 4723 4724 4725 4726 4727
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);
4728 4729
	else if (pte_none(ptent) || pte_file(ptent))
		page = mc_handle_file_pte(vma, addr, ptent, &ent);
D
Daisuke Nishimura 已提交
4730 4731 4732

	if (!page && !ent.val)
		return 0;
4733 4734 4735 4736 4737 4738 4739 4740 4741 4742 4743 4744 4745 4746 4747
	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
4748 4749
	/* There is a swap entry and a page doesn't exist or isn't charged */
	if (ent.val && !ret &&
4750 4751 4752 4753
			css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
		ret = MC_TARGET_SWAP;
		if (target)
			target->ent = ent;
4754 4755 4756 4757 4758 4759 4760 4761 4762 4763 4764 4765
	}
	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
4766
	VM_BUG_ON(pmd_trans_huge(*pmd));
4767 4768 4769 4770 4771 4772 4773
	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();

4774 4775 4776
	return 0;
}

4777 4778 4779 4780 4781
static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
{
	unsigned long precharge;
	struct vm_area_struct *vma;

4782
	down_read(&mm->mmap_sem);
4783 4784 4785 4786 4787 4788 4789 4790 4791 4792 4793
	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);
	}
4794
	up_read(&mm->mmap_sem);
4795 4796 4797 4798 4799 4800 4801 4802 4803

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

	return precharge;
}

static int mem_cgroup_precharge_mc(struct mm_struct *mm)
{
4804 4805 4806 4807 4808
	unsigned long precharge = mem_cgroup_count_precharge(mm);

	VM_BUG_ON(mc.moving_task);
	mc.moving_task = current;
	return mem_cgroup_do_precharge(precharge);
4809 4810
}

4811 4812
/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
static void __mem_cgroup_clear_mc(void)
4813
{
4814 4815 4816
	struct mem_cgroup *from = mc.from;
	struct mem_cgroup *to = mc.to;

4817
	/* we must uncharge all the leftover precharges from mc.to */
4818 4819 4820 4821 4822 4823 4824 4825 4826 4827 4828
	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;
4829
	}
4830 4831 4832 4833 4834 4835 4836 4837 4838 4839 4840 4841 4842 4843 4844 4845 4846 4847 4848
	/* 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;
	}
4849 4850 4851 4852 4853 4854 4855 4856 4857 4858 4859 4860 4861 4862 4863
	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();
4864
	spin_lock(&mc.lock);
4865 4866
	mc.from = NULL;
	mc.to = NULL;
4867
	spin_unlock(&mc.lock);
4868
	mem_cgroup_end_move(from);
4869 4870
}

4871 4872 4873 4874 4875 4876 4877 4878 4879 4880 4881 4882 4883 4884 4885 4886 4887 4888
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 */
4889 4890 4891 4892
		if (mm->owner == p) {
			VM_BUG_ON(mc.from);
			VM_BUG_ON(mc.to);
			VM_BUG_ON(mc.precharge);
4893
			VM_BUG_ON(mc.moved_charge);
4894
			VM_BUG_ON(mc.moved_swap);
4895
			mem_cgroup_start_move(from);
4896
			spin_lock(&mc.lock);
4897 4898
			mc.from = from;
			mc.to = mem;
4899
			spin_unlock(&mc.lock);
4900
			/* We set mc.moving_task later */
4901 4902 4903 4904

			ret = mem_cgroup_precharge_mc(mm);
			if (ret)
				mem_cgroup_clear_mc();
4905 4906
		}
		mmput(mm);
4907 4908 4909 4910 4911 4912 4913 4914 4915
	}
	return ret;
}

static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
				struct cgroup *cgroup,
				struct task_struct *p,
				bool threadgroup)
{
4916
	mem_cgroup_clear_mc();
4917 4918
}

4919 4920 4921
static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
				unsigned long addr, unsigned long end,
				struct mm_walk *walk)
4922
{
4923 4924 4925 4926 4927 4928
	int ret = 0;
	struct vm_area_struct *vma = walk->private;
	pte_t *pte;
	spinlock_t *ptl;

retry:
A
Andrea Arcangeli 已提交
4929
	VM_BUG_ON(pmd_trans_huge(*pmd));
4930 4931 4932 4933 4934 4935 4936
	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;
4937
		swp_entry_t ent;
4938 4939 4940 4941 4942 4943 4944 4945 4946 4947 4948

		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);
4949
			if (!mem_cgroup_move_account(pc,
4950
					mc.from, mc.to, false, PAGE_SIZE)) {
4951
				mc.precharge--;
4952 4953
				/* we uncharge from mc.from later. */
				mc.moved_charge++;
4954 4955 4956 4957 4958
			}
			putback_lru_page(page);
put:			/* is_target_pte_for_mc() gets the page */
			put_page(page);
			break;
4959 4960
		case MC_TARGET_SWAP:
			ent = target.ent;
4961 4962
			if (!mem_cgroup_move_swap_account(ent,
						mc.from, mc.to, false)) {
4963
				mc.precharge--;
4964 4965 4966
				/* we fixup refcnts and charges later. */
				mc.moved_swap++;
			}
4967
			break;
4968 4969 4970 4971 4972 4973 4974 4975 4976 4977 4978 4979 4980 4981
		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.
		 */
4982
		ret = mem_cgroup_do_precharge(1);
4983 4984 4985 4986 4987 4988 4989 4990 4991 4992 4993 4994
		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();
4995 4996 4997 4998 4999 5000 5001 5002 5003 5004 5005 5006 5007
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;
	}
5008 5009 5010 5011 5012 5013 5014 5015 5016 5017 5018 5019 5020 5021 5022 5023 5024 5025
	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;
	}
5026
	up_read(&mm->mmap_sem);
5027 5028
}

B
Balbir Singh 已提交
5029 5030 5031
static void mem_cgroup_move_task(struct cgroup_subsys *ss,
				struct cgroup *cont,
				struct cgroup *old_cont,
5032 5033
				struct task_struct *p,
				bool threadgroup)
B
Balbir Singh 已提交
5034
{
5035 5036 5037
	struct mm_struct *mm;

	if (!mc.to)
5038 5039 5040
		/* no need to move charge */
		return;

5041 5042 5043 5044 5045
	mm = get_task_mm(p);
	if (mm) {
		mem_cgroup_move_charge(mm);
		mmput(mm);
	}
5046
	mem_cgroup_clear_mc();
B
Balbir Singh 已提交
5047
}
5048 5049 5050 5051 5052 5053 5054 5055 5056 5057 5058 5059 5060 5061 5062 5063 5064 5065 5066 5067 5068 5069
#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
5070

B
Balbir Singh 已提交
5071 5072 5073 5074
struct cgroup_subsys mem_cgroup_subsys = {
	.name = "memory",
	.subsys_id = mem_cgroup_subsys_id,
	.create = mem_cgroup_create,
5075
	.pre_destroy = mem_cgroup_pre_destroy,
B
Balbir Singh 已提交
5076 5077
	.destroy = mem_cgroup_destroy,
	.populate = mem_cgroup_populate,
5078 5079
	.can_attach = mem_cgroup_can_attach,
	.cancel_attach = mem_cgroup_cancel_attach,
B
Balbir Singh 已提交
5080
	.attach = mem_cgroup_move_task,
5081
	.early_init = 0,
K
KAMEZAWA Hiroyuki 已提交
5082
	.use_id = 1,
B
Balbir Singh 已提交
5083
};
5084 5085

#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
5086 5087 5088
static int __init enable_swap_account(char *s)
{
	/* consider enabled if no parameter or 1 is given */
5089
	if (!(*s) || !strcmp(s, "=1"))
5090
		really_do_swap_account = 1;
5091
	else if (!strcmp(s, "=0"))
5092 5093 5094 5095
		really_do_swap_account = 0;
	return 1;
}
__setup("swapaccount", enable_swap_account);
5096 5097 5098

static int __init disable_swap_account(char *s)
{
5099
	printk_once("noswapaccount is deprecated and will be removed in 2.6.40. Use swapaccount=0 instead\n");
5100
	enable_swap_account("=0");
5101 5102 5103 5104
	return 1;
}
__setup("noswapaccount", disable_swap_account);
#endif