1/* memcontrol.c - Memory Controller
   2 *
   3 * Copyright IBM Corporation, 2007
   4 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
   5 *
   6 * Copyright 2007 OpenVZ SWsoft Inc
   7 * Author: Pavel Emelianov <xemul@openvz.org>
   8 *
   9 * Memory thresholds
  10 * Copyright (C) 2009 Nokia Corporation
  11 * Author: Kirill A. Shutemov
  12 *
  13 * Kernel Memory Controller
  14 * Copyright (C) 2012 Parallels Inc. and Google Inc.
  15 * Authors: Glauber Costa and Suleiman Souhlal
  16 *
  17 * This program is free software; you can redistribute it and/or modify
  18 * it under the terms of the GNU General Public License as published by
  19 * the Free Software Foundation; either version 2 of the License, or
  20 * (at your option) any later version.
  21 *
  22 * This program is distributed in the hope that it will be useful,
  23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25 * GNU General Public License for more details.
  26 */
  27
  28#include <linux/res_counter.h>
  29#include <linux/memcontrol.h>
  30#include <linux/cgroup.h>
  31#include <linux/mm.h>
 
 
  32#include <linux/hugetlb.h>
  33#include <linux/pagemap.h>
 
 
  34#include <linux/smp.h>
  35#include <linux/page-flags.h>
  36#include <linux/backing-dev.h>
  37#include <linux/bit_spinlock.h>
  38#include <linux/rcupdate.h>
  39#include <linux/limits.h>
  40#include <linux/export.h>
  41#include <linux/mutex.h>
  42#include <linux/rbtree.h>
  43#include <linux/slab.h>
  44#include <linux/swap.h>
  45#include <linux/swapops.h>
  46#include <linux/spinlock.h>
  47#include <linux/eventfd.h>
  48#include <linux/poll.h>
  49#include <linux/sort.h>
  50#include <linux/fs.h>
  51#include <linux/seq_file.h>
  52#include <linux/vmpressure.h>
 
  53#include <linux/mm_inline.h>
  54#include <linux/page_cgroup.h>
  55#include <linux/cpu.h>
  56#include <linux/oom.h>
  57#include <linux/lockdep.h>
  58#include <linux/file.h>
 
 
 
 
 
  59#include "internal.h"
  60#include <net/sock.h>
  61#include <net/ip.h>
  62#include <net/tcp_memcontrol.h>
  63#include "slab.h"
 
  64
  65#include <asm/uaccess.h>
  66
  67#include <trace/events/vmscan.h>
  68
  69struct cgroup_subsys memory_cgrp_subsys __read_mostly;
  70EXPORT_SYMBOL(memory_cgrp_subsys);
  71
  72#define MEM_CGROUP_RECLAIM_RETRIES	5
  73static struct mem_cgroup *root_mem_cgroup __read_mostly;
  74
  75#ifdef CONFIG_MEMCG_SWAP
  76/* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
  77int do_swap_account __read_mostly;
  78
  79/* for remember boot option*/
  80#ifdef CONFIG_MEMCG_SWAP_ENABLED
  81static int really_do_swap_account __initdata = 1;
  82#else
  83static int really_do_swap_account __initdata = 0;
  84#endif
  85
  86#else
  87#define do_swap_account		0
  88#endif
  89
 
 
  90
  91static const char * const mem_cgroup_stat_names[] = {
  92	"cache",
  93	"rss",
  94	"rss_huge",
  95	"mapped_file",
  96	"writeback",
  97	"swap",
  98};
  99
 100enum mem_cgroup_events_index {
 101	MEM_CGROUP_EVENTS_PGPGIN,	/* # of pages paged in */
 102	MEM_CGROUP_EVENTS_PGPGOUT,	/* # of pages paged out */
 103	MEM_CGROUP_EVENTS_PGFAULT,	/* # of page-faults */
 104	MEM_CGROUP_EVENTS_PGMAJFAULT,	/* # of major page-faults */
 105	MEM_CGROUP_EVENTS_NSTATS,
 106};
 107
 108static const char * const mem_cgroup_events_names[] = {
 109	"pgpgin",
 110	"pgpgout",
 111	"pgfault",
 112	"pgmajfault",
 113};
 114
 115static const char * const mem_cgroup_lru_names[] = {
 116	"inactive_anon",
 117	"active_anon",
 118	"inactive_file",
 119	"active_file",
 120	"unevictable",
 121};
 122
 123/*
 124 * Per memcg event counter is incremented at every pagein/pageout. With THP,
 125 * it will be incremated by the number of pages. This counter is used for
 126 * for trigger some periodic events. This is straightforward and better
 127 * than using jiffies etc. to handle periodic memcg event.
 128 */
 129enum mem_cgroup_events_target {
 130	MEM_CGROUP_TARGET_THRESH,
 131	MEM_CGROUP_TARGET_SOFTLIMIT,
 132	MEM_CGROUP_TARGET_NUMAINFO,
 133	MEM_CGROUP_NTARGETS,
 134};
 135#define THRESHOLDS_EVENTS_TARGET 128
 136#define SOFTLIMIT_EVENTS_TARGET 1024
 137#define NUMAINFO_EVENTS_TARGET	1024
 138
 139struct mem_cgroup_stat_cpu {
 140	long count[MEM_CGROUP_STAT_NSTATS];
 141	unsigned long events[MEM_CGROUP_EVENTS_NSTATS];
 142	unsigned long nr_page_events;
 143	unsigned long targets[MEM_CGROUP_NTARGETS];
 144};
 145
 146struct mem_cgroup_reclaim_iter {
 147	/*
 148	 * last scanned hierarchy member. Valid only if last_dead_count
 149	 * matches memcg->dead_count of the hierarchy root group.
 150	 */
 151	struct mem_cgroup *last_visited;
 152	int last_dead_count;
 153
 154	/* scan generation, increased every round-trip */
 155	unsigned int generation;
 156};
 157
 158/*
 159 * per-zone information in memory controller.
 160 */
 161struct mem_cgroup_per_zone {
 162	struct lruvec		lruvec;
 163	unsigned long		lru_size[NR_LRU_LISTS];
 164
 165	struct mem_cgroup_reclaim_iter reclaim_iter[DEF_PRIORITY + 1];
 166
 167	struct rb_node		tree_node;	/* RB tree node */
 168	unsigned long long	usage_in_excess;/* Set to the value by which */
 169						/* the soft limit is exceeded*/
 170	bool			on_tree;
 171	struct mem_cgroup	*memcg;		/* Back pointer, we cannot */
 172						/* use container_of	   */
 173};
 174
 175struct mem_cgroup_per_node {
 176	struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
 177};
 178
 179/*
 180 * Cgroups above their limits are maintained in a RB-Tree, independent of
 181 * their hierarchy representation
 182 */
 183
 184struct mem_cgroup_tree_per_zone {
 185	struct rb_root rb_root;
 
 186	spinlock_t lock;
 187};
 188
 189struct mem_cgroup_tree_per_node {
 190	struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
 191};
 192
 193struct mem_cgroup_tree {
 194	struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
 195};
 196
 197static struct mem_cgroup_tree soft_limit_tree __read_mostly;
 198
 199struct mem_cgroup_threshold {
 200	struct eventfd_ctx *eventfd;
 201	u64 threshold;
 202};
 203
 204/* For threshold */
 205struct mem_cgroup_threshold_ary {
 206	/* An array index points to threshold just below or equal to usage. */
 207	int current_threshold;
 208	/* Size of entries[] */
 209	unsigned int size;
 210	/* Array of thresholds */
 211	struct mem_cgroup_threshold entries[0];
 212};
 213
 214struct mem_cgroup_thresholds {
 215	/* Primary thresholds array */
 216	struct mem_cgroup_threshold_ary *primary;
 217	/*
 218	 * Spare threshold array.
 219	 * This is needed to make mem_cgroup_unregister_event() "never fail".
 220	 * It must be able to store at least primary->size - 1 entries.
 221	 */
 222	struct mem_cgroup_threshold_ary *spare;
 223};
 224
 225/* for OOM */
 226struct mem_cgroup_eventfd_list {
 227	struct list_head list;
 228	struct eventfd_ctx *eventfd;
 229};
 230
 231/*
 232 * cgroup_event represents events which userspace want to receive.
 233 */
 234struct mem_cgroup_event {
 235	/*
 236	 * memcg which the event belongs to.
 237	 */
 238	struct mem_cgroup *memcg;
 239	/*
 240	 * eventfd to signal userspace about the event.
 241	 */
 242	struct eventfd_ctx *eventfd;
 243	/*
 244	 * Each of these stored in a list by the cgroup.
 245	 */
 246	struct list_head list;
 247	/*
 248	 * register_event() callback will be used to add new userspace
 249	 * waiter for changes related to this event.  Use eventfd_signal()
 250	 * on eventfd to send notification to userspace.
 251	 */
 252	int (*register_event)(struct mem_cgroup *memcg,
 253			      struct eventfd_ctx *eventfd, const char *args);
 254	/*
 255	 * unregister_event() callback will be called when userspace closes
 256	 * the eventfd or on cgroup removing.  This callback must be set,
 257	 * if you want provide notification functionality.
 258	 */
 259	void (*unregister_event)(struct mem_cgroup *memcg,
 260				 struct eventfd_ctx *eventfd);
 261	/*
 262	 * All fields below needed to unregister event when
 263	 * userspace closes eventfd.
 264	 */
 265	poll_table pt;
 266	wait_queue_head_t *wqh;
 267	wait_queue_t wait;
 268	struct work_struct remove;
 269};
 270
 271static void mem_cgroup_threshold(struct mem_cgroup *memcg);
 272static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
 273
 274/*
 275 * The memory controller data structure. The memory controller controls both
 276 * page cache and RSS per cgroup. We would eventually like to provide
 277 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
 278 * to help the administrator determine what knobs to tune.
 279 *
 280 * TODO: Add a water mark for the memory controller. Reclaim will begin when
 281 * we hit the water mark. May be even add a low water mark, such that
 282 * no reclaim occurs from a cgroup at it's low water mark, this is
 283 * a feature that will be implemented much later in the future.
 284 */
 285struct mem_cgroup {
 286	struct cgroup_subsys_state css;
 287	/*
 288	 * the counter to account for memory usage
 289	 */
 290	struct res_counter res;
 291
 292	/* vmpressure notifications */
 293	struct vmpressure vmpressure;
 294
 295	/*
 296	 * the counter to account for mem+swap usage.
 297	 */
 298	struct res_counter memsw;
 299
 300	/*
 301	 * the counter to account for kernel memory usage.
 302	 */
 303	struct res_counter kmem;
 304	/*
 305	 * Should the accounting and control be hierarchical, per subtree?
 306	 */
 307	bool use_hierarchy;
 308	unsigned long kmem_account_flags; /* See KMEM_ACCOUNTED_*, below */
 309
 310	bool		oom_lock;
 311	atomic_t	under_oom;
 312	atomic_t	oom_wakeups;
 313
 314	int	swappiness;
 315	/* OOM-Killer disable */
 316	int		oom_kill_disable;
 317
 318	/* set when res.limit == memsw.limit */
 319	bool		memsw_is_minimum;
 320
 321	/* protect arrays of thresholds */
 322	struct mutex thresholds_lock;
 323
 324	/* thresholds for memory usage. RCU-protected */
 325	struct mem_cgroup_thresholds thresholds;
 326
 327	/* thresholds for mem+swap usage. RCU-protected */
 328	struct mem_cgroup_thresholds memsw_thresholds;
 329
 330	/* For oom notifier event fd */
 331	struct list_head oom_notify;
 332
 333	/*
 334	 * Should we move charges of a task when a task is moved into this
 335	 * mem_cgroup ? And what type of charges should we move ?
 336	 */
 337	unsigned long move_charge_at_immigrate;
 338	/*
 339	 * set > 0 if pages under this cgroup are moving to other cgroup.
 340	 */
 341	atomic_t	moving_account;
 342	/* taken only while moving_account > 0 */
 343	spinlock_t	move_lock;
 344	/*
 345	 * percpu counter.
 346	 */
 347	struct mem_cgroup_stat_cpu __percpu *stat;
 348	/*
 349	 * used when a cpu is offlined or other synchronizations
 350	 * See mem_cgroup_read_stat().
 351	 */
 352	struct mem_cgroup_stat_cpu nocpu_base;
 353	spinlock_t pcp_counter_lock;
 354
 355	atomic_t	dead_count;
 356#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
 357	struct cg_proto tcp_mem;
 358#endif
 359#if defined(CONFIG_MEMCG_KMEM)
 360	/* analogous to slab_common's slab_caches list. per-memcg */
 361	struct list_head memcg_slab_caches;
 362	/* Not a spinlock, we can take a lot of time walking the list */
 363	struct mutex slab_caches_mutex;
 364        /* Index in the kmem_cache->memcg_params->memcg_caches array */
 365	int kmemcg_id;
 366#endif
 367
 368	int last_scanned_node;
 369#if MAX_NUMNODES > 1
 370	nodemask_t	scan_nodes;
 371	atomic_t	numainfo_events;
 372	atomic_t	numainfo_updating;
 373#endif
 374
 375	/* List of events which userspace want to receive */
 376	struct list_head event_list;
 377	spinlock_t event_list_lock;
 378
 379	struct mem_cgroup_per_node *nodeinfo[0];
 380	/* WARNING: nodeinfo must be the last member here */
 381};
 382
 383/* internal only representation about the status of kmem accounting. */
 384enum {
 385	KMEM_ACCOUNTED_ACTIVE, /* accounted by this cgroup itself */
 386	KMEM_ACCOUNTED_DEAD, /* dead memcg with pending kmem charges */
 387};
 388
 389#ifdef CONFIG_MEMCG_KMEM
 390static inline void memcg_kmem_set_active(struct mem_cgroup *memcg)
 391{
 392	set_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags);
 393}
 394
 395static bool memcg_kmem_is_active(struct mem_cgroup *memcg)
 396{
 397	return test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags);
 398}
 399
 400static void memcg_kmem_mark_dead(struct mem_cgroup *memcg)
 401{
 402	/*
 403	 * Our caller must use css_get() first, because memcg_uncharge_kmem()
 404	 * will call css_put() if it sees the memcg is dead.
 405	 */
 406	smp_wmb();
 407	if (test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags))
 408		set_bit(KMEM_ACCOUNTED_DEAD, &memcg->kmem_account_flags);
 409}
 410
 411static bool memcg_kmem_test_and_clear_dead(struct mem_cgroup *memcg)
 412{
 413	return test_and_clear_bit(KMEM_ACCOUNTED_DEAD,
 414				  &memcg->kmem_account_flags);
 415}
 416#endif
 417
 418/* Stuffs for move charges at task migration. */
 419/*
 420 * Types of charges to be moved. "move_charge_at_immitgrate" and
 421 * "immigrate_flags" are treated as a left-shifted bitmap of these types.
 422 */
 423enum move_type {
 424	MOVE_CHARGE_TYPE_ANON,	/* private anonymous page and swap of it */
 425	MOVE_CHARGE_TYPE_FILE,	/* file page(including tmpfs) and swap of it */
 426	NR_MOVE_TYPE,
 427};
 428
 429/* "mc" and its members are protected by cgroup_mutex */
 430static struct move_charge_struct {
 431	spinlock_t	  lock; /* for from, to */
 
 432	struct mem_cgroup *from;
 433	struct mem_cgroup *to;
 434	unsigned long immigrate_flags;
 435	unsigned long precharge;
 436	unsigned long moved_charge;
 437	unsigned long moved_swap;
 438	struct task_struct *moving_task;	/* a task moving charges */
 439	wait_queue_head_t waitq;		/* a waitq for other context */
 440} mc = {
 441	.lock = __SPIN_LOCK_UNLOCKED(mc.lock),
 442	.waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
 443};
 444
 445static bool move_anon(void)
 446{
 447	return test_bit(MOVE_CHARGE_TYPE_ANON, &mc.immigrate_flags);
 448}
 449
 450static bool move_file(void)
 451{
 452	return test_bit(MOVE_CHARGE_TYPE_FILE, &mc.immigrate_flags);
 453}
 454
 455/*
 456 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
 457 * limit reclaim to prevent infinite loops, if they ever occur.
 458 */
 459#define	MEM_CGROUP_MAX_RECLAIM_LOOPS		100
 460#define	MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS	2
 461
 462enum charge_type {
 463	MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
 464	MEM_CGROUP_CHARGE_TYPE_ANON,
 465	MEM_CGROUP_CHARGE_TYPE_SWAPOUT,	/* for accounting swapcache */
 466	MEM_CGROUP_CHARGE_TYPE_DROP,	/* a page was unused swap cache */
 467	NR_CHARGE_TYPE,
 468};
 469
 470/* for encoding cft->private value on file */
 471enum res_type {
 472	_MEM,
 473	_MEMSWAP,
 474	_OOM_TYPE,
 475	_KMEM,
 
 476};
 477
 478#define MEMFILE_PRIVATE(x, val)	((x) << 16 | (val))
 479#define MEMFILE_TYPE(val)	((val) >> 16 & 0xffff)
 480#define MEMFILE_ATTR(val)	((val) & 0xffff)
 481/* Used for OOM nofiier */
 482#define OOM_CONTROL		(0)
 483
 484/*
 485 * Reclaim flags for mem_cgroup_hierarchical_reclaim
 
 
 486 */
 487#define MEM_CGROUP_RECLAIM_NOSWAP_BIT	0x0
 488#define MEM_CGROUP_RECLAIM_NOSWAP	(1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
 489#define MEM_CGROUP_RECLAIM_SHRINK_BIT	0x1
 490#define MEM_CGROUP_RECLAIM_SHRINK	(1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
 491
 492/*
 493 * The memcg_create_mutex will be held whenever a new cgroup is created.
 494 * As a consequence, any change that needs to protect against new child cgroups
 495 * appearing has to hold it as well.
 496 */
 497static DEFINE_MUTEX(memcg_create_mutex);
 498
 499struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s)
 500{
 501	return s ? container_of(s, struct mem_cgroup, css) : NULL;
 
 502}
 503
 504/* Some nice accessors for the vmpressure. */
 505struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg)
 506{
 507	if (!memcg)
 508		memcg = root_mem_cgroup;
 509	return &memcg->vmpressure;
 510}
 511
 512struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr)
 513{
 514	return &container_of(vmpr, struct mem_cgroup, vmpressure)->css;
 515}
 516
 517static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
 
 
 
 
 
 
 518{
 519	return (memcg == root_mem_cgroup);
 520}
 521
 522/*
 523 * We restrict the id in the range of [1, 65535], so it can fit into
 524 * an unsigned short.
 525 */
 526#define MEM_CGROUP_ID_MAX	USHRT_MAX
 527
 528static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
 529{
 
 
 
 
 
 530	/*
 531	 * The ID of the root cgroup is 0, but memcg treat 0 as an
 532	 * invalid ID, so we return (cgroup_id + 1).
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 533	 */
 534	return memcg->css.cgroup->id + 1;
 535}
 
 536
 537static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
 538{
 539	struct cgroup_subsys_state *css;
 540
 541	css = css_from_id(id - 1, &memory_cgrp_subsys);
 542	return mem_cgroup_from_css(css);
 543}
 544
 545/* Writing them here to avoid exposing memcg's inner layout */
 546#if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
 
 547
 548void sock_update_memcg(struct sock *sk)
 549{
 550	if (mem_cgroup_sockets_enabled) {
 551		struct mem_cgroup *memcg;
 552		struct cg_proto *cg_proto;
 553
 554		BUG_ON(!sk->sk_prot->proto_cgroup);
 555
 556		/* Socket cloning can throw us here with sk_cgrp already
 557		 * filled. It won't however, necessarily happen from
 558		 * process context. So the test for root memcg given
 559		 * the current task's memcg won't help us in this case.
 560		 *
 561		 * Respecting the original socket's memcg is a better
 562		 * decision in this case.
 563		 */
 564		if (sk->sk_cgrp) {
 565			BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg));
 566			css_get(&sk->sk_cgrp->memcg->css);
 567			return;
 568		}
 569
 570		rcu_read_lock();
 571		memcg = mem_cgroup_from_task(current);
 572		cg_proto = sk->sk_prot->proto_cgroup(memcg);
 573		if (!mem_cgroup_is_root(memcg) &&
 574		    memcg_proto_active(cg_proto) && css_tryget(&memcg->css)) {
 575			sk->sk_cgrp = cg_proto;
 576		}
 577		rcu_read_unlock();
 578	}
 
 
 579}
 580EXPORT_SYMBOL(sock_update_memcg);
 581
 582void sock_release_memcg(struct sock *sk)
 
 583{
 584	if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
 585		struct mem_cgroup *memcg;
 586		WARN_ON(!sk->sk_cgrp->memcg);
 587		memcg = sk->sk_cgrp->memcg;
 588		css_put(&sk->sk_cgrp->memcg->css);
 589	}
 590}
 591
 592struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
 593{
 594	if (!memcg || mem_cgroup_is_root(memcg))
 595		return NULL;
 596
 597	return &memcg->tcp_mem;
 598}
 599EXPORT_SYMBOL(tcp_proto_cgroup);
 600
 601static void disarm_sock_keys(struct mem_cgroup *memcg)
 602{
 603	if (!memcg_proto_activated(&memcg->tcp_mem))
 604		return;
 605	static_key_slow_dec(&memcg_socket_limit_enabled);
 606}
 607#else
 608static void disarm_sock_keys(struct mem_cgroup *memcg)
 609{
 610}
 611#endif
 612
 613#ifdef CONFIG_MEMCG_KMEM
 614/*
 615 * This will be the memcg's index in each cache's ->memcg_params->memcg_caches.
 616 * The main reason for not using cgroup id for this:
 617 *  this works better in sparse environments, where we have a lot of memcgs,
 618 *  but only a few kmem-limited. Or also, if we have, for instance, 200
 619 *  memcgs, and none but the 200th is kmem-limited, we'd have to have a
 620 *  200 entry array for that.
 621 *
 622 * The current size of the caches array is stored in
 623 * memcg_limited_groups_array_size.  It will double each time we have to
 624 * increase it.
 625 */
 626static DEFINE_IDA(kmem_limited_groups);
 627int memcg_limited_groups_array_size;
 628
 629/*
 630 * MIN_SIZE is different than 1, because we would like to avoid going through
 631 * the alloc/free process all the time. In a small machine, 4 kmem-limited
 632 * cgroups is a reasonable guess. In the future, it could be a parameter or
 633 * tunable, but that is strictly not necessary.
 634 *
 635 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
 636 * this constant directly from cgroup, but it is understandable that this is
 637 * better kept as an internal representation in cgroup.c. In any case, the
 638 * cgrp_id space is not getting any smaller, and we don't have to necessarily
 639 * increase ours as well if it increases.
 640 */
 641#define MEMCG_CACHES_MIN_SIZE 4
 642#define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
 643
 644/*
 645 * A lot of the calls to the cache allocation functions are expected to be
 646 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
 647 * conditional to this static branch, we'll have to allow modules that does
 648 * kmem_cache_alloc and the such to see this symbol as well
 649 */
 650struct static_key memcg_kmem_enabled_key;
 651EXPORT_SYMBOL(memcg_kmem_enabled_key);
 652
 653static void disarm_kmem_keys(struct mem_cgroup *memcg)
 654{
 655	if (memcg_kmem_is_active(memcg)) {
 656		static_key_slow_dec(&memcg_kmem_enabled_key);
 657		ida_simple_remove(&kmem_limited_groups, memcg->kmemcg_id);
 658	}
 659	/*
 660	 * This check can't live in kmem destruction function,
 661	 * since the charges will outlive the cgroup
 662	 */
 663	WARN_ON(res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0);
 664}
 665#else
 666static void disarm_kmem_keys(struct mem_cgroup *memcg)
 667{
 668}
 669#endif /* CONFIG_MEMCG_KMEM */
 670
 671static void disarm_static_keys(struct mem_cgroup *memcg)
 
 
 
 
 
 
 
 
 
 
 
 672{
 673	disarm_sock_keys(memcg);
 674	disarm_kmem_keys(memcg);
 675}
 676
 677static void drain_all_stock_async(struct mem_cgroup *memcg);
 678
 679static struct mem_cgroup_per_zone *
 680mem_cgroup_zoneinfo(struct mem_cgroup *memcg, int nid, int zid)
 681{
 682	VM_BUG_ON((unsigned)nid >= nr_node_ids);
 683	return &memcg->nodeinfo[nid]->zoneinfo[zid];
 684}
 685
 686struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg)
 687{
 688	return &memcg->css;
 689}
 690
 691static struct mem_cgroup_per_zone *
 692page_cgroup_zoneinfo(struct mem_cgroup *memcg, struct page *page)
 693{
 694	int nid = page_to_nid(page);
 695	int zid = page_zonenum(page);
 696
 697	return mem_cgroup_zoneinfo(memcg, nid, zid);
 698}
 699
 700static struct mem_cgroup_tree_per_zone *
 701soft_limit_tree_node_zone(int nid, int zid)
 
 
 
 702{
 703	return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
 704}
 705
 706static struct mem_cgroup_tree_per_zone *
 707soft_limit_tree_from_page(struct page *page)
 708{
 709	int nid = page_to_nid(page);
 710	int zid = page_zonenum(page);
 711
 712	return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
 
 
 
 
 
 713}
 714
 715static void
 716__mem_cgroup_insert_exceeded(struct mem_cgroup *memcg,
 717				struct mem_cgroup_per_zone *mz,
 718				struct mem_cgroup_tree_per_zone *mctz,
 719				unsigned long long new_usage_in_excess)
 720{
 721	struct rb_node **p = &mctz->rb_root.rb_node;
 722	struct rb_node *parent = NULL;
 723	struct mem_cgroup_per_zone *mz_node;
 
 724
 725	if (mz->on_tree)
 726		return;
 727
 728	mz->usage_in_excess = new_usage_in_excess;
 729	if (!mz->usage_in_excess)
 730		return;
 731	while (*p) {
 732		parent = *p;
 733		mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
 734					tree_node);
 735		if (mz->usage_in_excess < mz_node->usage_in_excess)
 736			p = &(*p)->rb_left;
 737		/*
 738		 * We can't avoid mem cgroups that are over their soft
 739		 * limit by the same amount
 740		 */
 741		else if (mz->usage_in_excess >= mz_node->usage_in_excess)
 742			p = &(*p)->rb_right;
 
 743	}
 
 
 
 
 744	rb_link_node(&mz->tree_node, parent, p);
 745	rb_insert_color(&mz->tree_node, &mctz->rb_root);
 746	mz->on_tree = true;
 747}
 748
 749static void
 750__mem_cgroup_remove_exceeded(struct mem_cgroup *memcg,
 751				struct mem_cgroup_per_zone *mz,
 752				struct mem_cgroup_tree_per_zone *mctz)
 753{
 754	if (!mz->on_tree)
 755		return;
 
 
 
 
 756	rb_erase(&mz->tree_node, &mctz->rb_root);
 757	mz->on_tree = false;
 758}
 759
 760static void
 761mem_cgroup_remove_exceeded(struct mem_cgroup *memcg,
 762				struct mem_cgroup_per_zone *mz,
 763				struct mem_cgroup_tree_per_zone *mctz)
 764{
 765	spin_lock(&mctz->lock);
 766	__mem_cgroup_remove_exceeded(memcg, mz, mctz);
 767	spin_unlock(&mctz->lock);
 
 
 768}
 769
 
 
 
 
 
 
 
 
 770
 771static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
 
 
 
 772{
 773	unsigned long long excess;
 774	struct mem_cgroup_per_zone *mz;
 775	struct mem_cgroup_tree_per_zone *mctz;
 776	int nid = page_to_nid(page);
 777	int zid = page_zonenum(page);
 778	mctz = soft_limit_tree_from_page(page);
 
 
 
 779
 
 
 
 780	/*
 781	 * Necessary to update all ancestors when hierarchy is used.
 782	 * because their event counter is not touched.
 783	 */
 784	for (; memcg; memcg = parent_mem_cgroup(memcg)) {
 785		mz = mem_cgroup_zoneinfo(memcg, nid, zid);
 786		excess = res_counter_soft_limit_excess(&memcg->res);
 787		/*
 788		 * We have to update the tree if mz is on RB-tree or
 789		 * mem is over its softlimit.
 790		 */
 791		if (excess || mz->on_tree) {
 792			spin_lock(&mctz->lock);
 
 
 793			/* if on-tree, remove it */
 794			if (mz->on_tree)
 795				__mem_cgroup_remove_exceeded(memcg, mz, mctz);
 796			/*
 797			 * Insert again. mz->usage_in_excess will be updated.
 798			 * If excess is 0, no tree ops.
 799			 */
 800			__mem_cgroup_insert_exceeded(memcg, mz, mctz, excess);
 801			spin_unlock(&mctz->lock);
 802		}
 803	}
 804}
 805
 806static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
 807{
 808	int node, zone;
 809	struct mem_cgroup_per_zone *mz;
 810	struct mem_cgroup_tree_per_zone *mctz;
 811
 812	for_each_node(node) {
 813		for (zone = 0; zone < MAX_NR_ZONES; zone++) {
 814			mz = mem_cgroup_zoneinfo(memcg, node, zone);
 815			mctz = soft_limit_tree_node_zone(node, zone);
 816			mem_cgroup_remove_exceeded(memcg, mz, mctz);
 817		}
 818	}
 819}
 820
 821static struct mem_cgroup_per_zone *
 822__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
 823{
 824	struct rb_node *rightmost = NULL;
 825	struct mem_cgroup_per_zone *mz;
 826
 827retry:
 828	mz = NULL;
 829	rightmost = rb_last(&mctz->rb_root);
 830	if (!rightmost)
 831		goto done;		/* Nothing to reclaim from */
 832
 833	mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
 
 834	/*
 835	 * Remove the node now but someone else can add it back,
 836	 * we will to add it back at the end of reclaim to its correct
 837	 * position in the tree.
 838	 */
 839	__mem_cgroup_remove_exceeded(mz->memcg, mz, mctz);
 840	if (!res_counter_soft_limit_excess(&mz->memcg->res) ||
 841		!css_tryget(&mz->memcg->css))
 842		goto retry;
 843done:
 844	return mz;
 845}
 846
 847static struct mem_cgroup_per_zone *
 848mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
 849{
 850	struct mem_cgroup_per_zone *mz;
 851
 852	spin_lock(&mctz->lock);
 853	mz = __mem_cgroup_largest_soft_limit_node(mctz);
 854	spin_unlock(&mctz->lock);
 855	return mz;
 856}
 857
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 858/*
 859 * Implementation Note: reading percpu statistics for memcg.
 860 *
 861 * Both of vmstat[] and percpu_counter has threshold and do periodic
 862 * synchronization to implement "quick" read. There are trade-off between
 863 * reading cost and precision of value. Then, we may have a chance to implement
 864 * a periodic synchronizion of counter in memcg's counter.
 865 *
 866 * But this _read() function is used for user interface now. The user accounts
 867 * memory usage by memory cgroup and he _always_ requires exact value because
 868 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
 869 * have to visit all online cpus and make sum. So, for now, unnecessary
 870 * synchronization is not implemented. (just implemented for cpu hotplug)
 871 *
 872 * If there are kernel internal actions which can make use of some not-exact
 873 * value, and reading all cpu value can be performance bottleneck in some
 874 * common workload, threashold and synchonization as vmstat[] should be
 875 * implemented.
 876 */
 877static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
 878				 enum mem_cgroup_stat_index idx)
 879{
 880	long val = 0;
 881	int cpu;
 882
 883	get_online_cpus();
 884	for_each_online_cpu(cpu)
 885		val += per_cpu(memcg->stat->count[idx], cpu);
 886#ifdef CONFIG_HOTPLUG_CPU
 887	spin_lock(&memcg->pcp_counter_lock);
 888	val += memcg->nocpu_base.count[idx];
 889	spin_unlock(&memcg->pcp_counter_lock);
 890#endif
 891	put_online_cpus();
 892	return val;
 893}
 894
 895static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
 896					 bool charge)
 897{
 898	int val = (charge) ? 1 : -1;
 899	this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val);
 900}
 901
 902static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
 903					    enum mem_cgroup_events_index idx)
 904{
 905	unsigned long val = 0;
 906	int cpu;
 907
 908	get_online_cpus();
 909	for_each_online_cpu(cpu)
 910		val += per_cpu(memcg->stat->events[idx], cpu);
 911#ifdef CONFIG_HOTPLUG_CPU
 912	spin_lock(&memcg->pcp_counter_lock);
 913	val += memcg->nocpu_base.events[idx];
 914	spin_unlock(&memcg->pcp_counter_lock);
 915#endif
 916	put_online_cpus();
 917	return val;
 918}
 919
 920static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
 921					 struct page *page,
 922					 bool anon, int nr_pages)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 923{
 924	/*
 925	 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
 926	 * counted as CACHE even if it's on ANON LRU.
 927	 */
 928	if (anon)
 929		__this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS],
 930				nr_pages);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 931	else
 932		__this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE],
 933				nr_pages);
 934
 935	if (PageTransHuge(page))
 936		__this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
 937				nr_pages);
 
 
 
 
 
 
 
 938
 939	/* pagein of a big page is an event. So, ignore page size */
 940	if (nr_pages > 0)
 941		__this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
 942	else {
 943		__this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
 944		nr_pages = -nr_pages; /* for event */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 945	}
 946
 947	__this_cpu_add(memcg->stat->nr_page_events, nr_pages);
 
 
 
 
 
 
 
 948}
 949
 950unsigned long
 951mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
 
 
 
 
 
 
 
 
 
 
 952{
 953	struct mem_cgroup_per_zone *mz;
 
 954
 955	mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
 956	return mz->lru_size[lru];
 
 957}
 958
 959static unsigned long
 960mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid,
 961			unsigned int lru_mask)
 962{
 963	struct mem_cgroup_per_zone *mz;
 964	enum lru_list lru;
 965	unsigned long ret = 0;
 966
 967	mz = mem_cgroup_zoneinfo(memcg, nid, zid);
 
 
 
 
 
 
 
 968
 969	for_each_lru(lru) {
 970		if (BIT(lru) & lru_mask)
 971			ret += mz->lru_size[lru];
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 972	}
 973	return ret;
 974}
 975
 976static unsigned long
 977mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
 978			int nid, unsigned int lru_mask)
 979{
 980	u64 total = 0;
 981	int zid;
 982
 983	for (zid = 0; zid < MAX_NR_ZONES; zid++)
 984		total += mem_cgroup_zone_nr_lru_pages(memcg,
 985						nid, zid, lru_mask);
 986
 987	return total;
 
 
 
 
 
 
 988}
 989
 990static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
 991			unsigned int lru_mask)
 992{
 993	int nid;
 994	u64 total = 0;
 995
 996	for_each_node_state(nid, N_MEMORY)
 997		total += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask);
 998	return total;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 999}
1000
1001static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
1002				       enum mem_cgroup_events_target target)
1003{
1004	unsigned long val, next;
1005
1006	val = __this_cpu_read(memcg->stat->nr_page_events);
1007	next = __this_cpu_read(memcg->stat->targets[target]);
1008	/* from time_after() in jiffies.h */
1009	if ((long)next - (long)val < 0) {
1010		switch (target) {
1011		case MEM_CGROUP_TARGET_THRESH:
1012			next = val + THRESHOLDS_EVENTS_TARGET;
1013			break;
1014		case MEM_CGROUP_TARGET_SOFTLIMIT:
1015			next = val + SOFTLIMIT_EVENTS_TARGET;
1016			break;
1017		case MEM_CGROUP_TARGET_NUMAINFO:
1018			next = val + NUMAINFO_EVENTS_TARGET;
1019			break;
1020		default:
1021			break;
1022		}
1023		__this_cpu_write(memcg->stat->targets[target], next);
1024		return true;
1025	}
1026	return false;
1027}
1028
1029/*
1030 * Check events in order.
1031 *
1032 */
1033static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
1034{
1035	preempt_disable();
 
 
1036	/* threshold event is triggered in finer grain than soft limit */
1037	if (unlikely(mem_cgroup_event_ratelimit(memcg,
1038						MEM_CGROUP_TARGET_THRESH))) {
1039		bool do_softlimit;
1040		bool do_numainfo __maybe_unused;
1041
1042		do_softlimit = mem_cgroup_event_ratelimit(memcg,
1043						MEM_CGROUP_TARGET_SOFTLIMIT);
1044#if MAX_NUMNODES > 1
1045		do_numainfo = mem_cgroup_event_ratelimit(memcg,
1046						MEM_CGROUP_TARGET_NUMAINFO);
1047#endif
1048		preempt_enable();
1049
1050		mem_cgroup_threshold(memcg);
1051		if (unlikely(do_softlimit))
1052			mem_cgroup_update_tree(memcg, page);
1053#if MAX_NUMNODES > 1
1054		if (unlikely(do_numainfo))
1055			atomic_inc(&memcg->numainfo_events);
1056#endif
1057	} else
1058		preempt_enable();
1059}
1060
1061struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
1062{
1063	/*
1064	 * mm_update_next_owner() may clear mm->owner to NULL
1065	 * if it races with swapoff, page migration, etc.
1066	 * So this can be called with p == NULL.
1067	 */
1068	if (unlikely(!p))
1069		return NULL;
1070
1071	return mem_cgroup_from_css(task_css(p, memory_cgrp_id));
1072}
 
1073
1074static struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
1075{
1076	struct mem_cgroup *memcg = NULL;
1077
1078	rcu_read_lock();
1079	do {
1080		/*
1081		 * Page cache insertions can happen withou an
1082		 * actual mm context, e.g. during disk probing
1083		 * on boot, loopback IO, acct() writes etc.
1084		 */
1085		if (unlikely(!mm))
1086			memcg = root_mem_cgroup;
1087		else {
1088			memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
1089			if (unlikely(!memcg))
1090				memcg = root_mem_cgroup;
1091		}
1092	} while (!css_tryget(&memcg->css));
1093	rcu_read_unlock();
1094	return memcg;
1095}
1096
1097/*
1098 * Returns a next (in a pre-order walk) alive memcg (with elevated css
1099 * ref. count) or NULL if the whole root's subtree has been visited.
1100 *
1101 * helper function to be used by mem_cgroup_iter
 
 
 
 
 
1102 */
1103static struct mem_cgroup *__mem_cgroup_iter_next(struct mem_cgroup *root,
1104		struct mem_cgroup *last_visited)
1105{
1106	struct cgroup_subsys_state *prev_css, *next_css;
1107
1108	prev_css = last_visited ? &last_visited->css : NULL;
1109skip_node:
1110	next_css = css_next_descendant_pre(prev_css, &root->css);
1111
1112	/*
1113	 * Even if we found a group we have to make sure it is
1114	 * alive. css && !memcg means that the groups should be
1115	 * skipped and we should continue the tree walk.
1116	 * last_visited css is safe to use because it is
1117	 * protected by css_get and the tree walk is rcu safe.
1118	 *
1119	 * We do not take a reference on the root of the tree walk
1120	 * because we might race with the root removal when it would
1121	 * be the only node in the iterated hierarchy and mem_cgroup_iter
1122	 * would end up in an endless loop because it expects that at
1123	 * least one valid node will be returned. Root cannot disappear
1124	 * because caller of the iterator should hold it already so
1125	 * skipping css reference should be safe.
1126	 */
1127	if (next_css) {
1128		if ((next_css == &root->css) ||
1129		    ((next_css->flags & CSS_ONLINE) && css_tryget(next_css)))
1130			return mem_cgroup_from_css(next_css);
1131
1132		prev_css = next_css;
1133		goto skip_node;
1134	}
1135
1136	return NULL;
 
 
 
 
 
 
 
1137}
 
1138
1139static void mem_cgroup_iter_invalidate(struct mem_cgroup *root)
 
 
 
1140{
1141	/*
1142	 * When a group in the hierarchy below root is destroyed, the
1143	 * hierarchy iterator can no longer be trusted since it might
1144	 * have pointed to the destroyed group.  Invalidate it.
1145	 */
1146	atomic_inc(&root->dead_count);
1147}
1148
1149static struct mem_cgroup *
1150mem_cgroup_iter_load(struct mem_cgroup_reclaim_iter *iter,
1151		     struct mem_cgroup *root,
1152		     int *sequence)
1153{
1154	struct mem_cgroup *position = NULL;
1155	/*
1156	 * A cgroup destruction happens in two stages: offlining and
1157	 * release.  They are separated by a RCU grace period.
1158	 *
1159	 * If the iterator is valid, we may still race with an
1160	 * offlining.  The RCU lock ensures the object won't be
1161	 * released, tryget will fail if we lost the race.
1162	 */
1163	*sequence = atomic_read(&root->dead_count);
1164	if (iter->last_dead_count == *sequence) {
1165		smp_rmb();
1166		position = iter->last_visited;
1167
1168		/*
1169		 * We cannot take a reference to root because we might race
1170		 * with root removal and returning NULL would end up in
1171		 * an endless loop on the iterator user level when root
1172		 * would be returned all the time.
1173		 */
1174		if (position && position != root &&
1175				!css_tryget(&position->css))
1176			position = NULL;
1177	}
1178	return position;
1179}
1180
1181static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter *iter,
1182				   struct mem_cgroup *last_visited,
1183				   struct mem_cgroup *new_position,
1184				   struct mem_cgroup *root,
1185				   int sequence)
1186{
1187	/* root reference counting symmetric to mem_cgroup_iter_load */
1188	if (last_visited && last_visited != root)
1189		css_put(&last_visited->css);
1190	/*
1191	 * We store the sequence count from the time @last_visited was
1192	 * loaded successfully instead of rereading it here so that we
1193	 * don't lose destruction events in between.  We could have
1194	 * raced with the destruction of @new_position after all.
1195	 */
1196	iter->last_visited = new_position;
1197	smp_wmb();
1198	iter->last_dead_count = sequence;
1199}
1200
1201/**
1202 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1203 * @root: hierarchy root
1204 * @prev: previously returned memcg, NULL on first invocation
1205 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1206 *
1207 * Returns references to children of the hierarchy below @root, or
1208 * @root itself, or %NULL after a full round-trip.
1209 *
1210 * Caller must pass the return value in @prev on subsequent
1211 * invocations for reference counting, or use mem_cgroup_iter_break()
1212 * to cancel a hierarchy walk before the round-trip is complete.
1213 *
1214 * Reclaimers can specify a zone and a priority level in @reclaim to
1215 * divide up the memcgs in the hierarchy among all concurrent
1216 * reclaimers operating on the same zone and priority.
1217 */
1218struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
1219				   struct mem_cgroup *prev,
1220				   struct mem_cgroup_reclaim_cookie *reclaim)
1221{
 
 
1222	struct mem_cgroup *memcg = NULL;
1223	struct mem_cgroup *last_visited = NULL;
1224
1225	if (mem_cgroup_disabled())
1226		return NULL;
1227
1228	if (!root)
1229		root = root_mem_cgroup;
1230
1231	if (prev && !reclaim)
1232		last_visited = prev;
1233
1234	if (!root->use_hierarchy && root != root_mem_cgroup) {
1235		if (prev)
1236			goto out_css_put;
1237		return root;
1238	}
1239
1240	rcu_read_lock();
1241	while (!memcg) {
1242		struct mem_cgroup_reclaim_iter *uninitialized_var(iter);
1243		int uninitialized_var(seq);
1244
1245		if (reclaim) {
1246			int nid = zone_to_nid(reclaim->zone);
1247			int zid = zone_idx(reclaim->zone);
1248			struct mem_cgroup_per_zone *mz;
1249
1250			mz = mem_cgroup_zoneinfo(root, nid, zid);
1251			iter = &mz->reclaim_iter[reclaim->priority];
1252			if (prev && reclaim->generation != iter->generation) {
1253				iter->last_visited = NULL;
1254				goto out_unlock;
1255			}
1256
1257			last_visited = mem_cgroup_iter_load(iter, root, &seq);
 
 
 
 
 
 
 
 
 
 
 
 
1258		}
 
 
 
1259
1260		memcg = __mem_cgroup_iter_next(root, last_visited);
 
1261
1262		if (reclaim) {
1263			mem_cgroup_iter_update(iter, last_visited, memcg, root,
1264					seq);
 
 
 
 
 
 
 
 
 
 
1265
1266			if (!memcg)
1267				iter->generation++;
1268			else if (!prev && memcg)
1269				reclaim->generation = iter->generation;
 
 
 
 
1270		}
 
1271
1272		if (prev && !memcg)
1273			goto out_unlock;
 
 
 
 
 
 
 
 
 
 
 
1274	}
 
1275out_unlock:
1276	rcu_read_unlock();
1277out_css_put:
1278	if (prev && prev != root)
1279		css_put(&prev->css);
1280
1281	return memcg;
1282}
1283
1284/**
1285 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1286 * @root: hierarchy root
1287 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1288 */
1289void mem_cgroup_iter_break(struct mem_cgroup *root,
1290			   struct mem_cgroup *prev)
1291{
1292	if (!root)
1293		root = root_mem_cgroup;
1294	if (prev && prev != root)
1295		css_put(&prev->css);
1296}
1297
1298/*
1299 * Iteration constructs for visiting all cgroups (under a tree).  If
1300 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1301 * be used for reference counting.
1302 */
1303#define for_each_mem_cgroup_tree(iter, root)		\
1304	for (iter = mem_cgroup_iter(root, NULL, NULL);	\
1305	     iter != NULL;				\
1306	     iter = mem_cgroup_iter(root, iter, NULL))
1307
1308#define for_each_mem_cgroup(iter)			\
1309	for (iter = mem_cgroup_iter(NULL, NULL, NULL);	\
1310	     iter != NULL;				\
1311	     iter = mem_cgroup_iter(NULL, iter, NULL))
 
 
1312
1313void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
1314{
1315	struct mem_cgroup *memcg;
 
1316
1317	rcu_read_lock();
1318	memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
1319	if (unlikely(!memcg))
1320		goto out;
1321
1322	switch (idx) {
1323	case PGFAULT:
1324		this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]);
1325		break;
1326	case PGMAJFAULT:
1327		this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
1328		break;
1329	default:
1330		BUG();
1331	}
1332out:
1333	rcu_read_unlock();
1334}
1335EXPORT_SYMBOL(__mem_cgroup_count_vm_event);
1336
1337/**
1338 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1339 * @zone: zone of the wanted lruvec
1340 * @memcg: memcg of the wanted lruvec
 
 
 
 
 
 
1341 *
1342 * Returns the lru list vector holding pages for the given @zone and
1343 * @mem.  This can be the global zone lruvec, if the memory controller
1344 * is disabled.
1345 */
1346struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
1347				      struct mem_cgroup *memcg)
1348{
1349	struct mem_cgroup_per_zone *mz;
1350	struct lruvec *lruvec;
1351
1352	if (mem_cgroup_disabled()) {
1353		lruvec = &zone->lruvec;
1354		goto out;
 
 
 
 
 
 
 
 
 
 
 
1355	}
 
1356
1357	mz = mem_cgroup_zoneinfo(memcg, zone_to_nid(zone), zone_idx(zone));
1358	lruvec = &mz->lruvec;
1359out:
1360	/*
1361	 * Since a node can be onlined after the mem_cgroup was created,
1362	 * we have to be prepared to initialize lruvec->zone here;
1363	 * and if offlined then reonlined, we need to reinitialize it.
1364	 */
1365	if (unlikely(lruvec->zone != zone))
1366		lruvec->zone = zone;
1367	return lruvec;
 
 
 
1368}
 
1369
1370/*
1371 * Following LRU functions are allowed to be used without PCG_LOCK.
1372 * Operations are called by routine of global LRU independently from memcg.
1373 * What we have to take care of here is validness of pc->mem_cgroup.
 
 
 
 
 
1374 *
1375 * Changes to pc->mem_cgroup happens when
1376 * 1. charge
1377 * 2. moving account
1378 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
1379 * It is added to LRU before charge.
1380 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
1381 * When moving account, the page is not on LRU. It's isolated.
1382 */
 
 
 
 
 
 
 
 
 
1383
1384/**
1385 * mem_cgroup_page_lruvec - return lruvec for adding an lru page
1386 * @page: the page
1387 * @zone: zone of the page
 
 
 
 
 
 
 
 
1388 */
1389struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone)
1390{
1391	struct mem_cgroup_per_zone *mz;
1392	struct mem_cgroup *memcg;
1393	struct page_cgroup *pc;
1394	struct lruvec *lruvec;
1395
1396	if (mem_cgroup_disabled()) {
1397		lruvec = &zone->lruvec;
1398		goto out;
1399	}
1400
1401	pc = lookup_page_cgroup(page);
1402	memcg = pc->mem_cgroup;
1403
1404	/*
1405	 * Surreptitiously switch any uncharged offlist page to root:
1406	 * an uncharged page off lru does nothing to secure
1407	 * its former mem_cgroup from sudden removal.
1408	 *
1409	 * Our caller holds lru_lock, and PageCgroupUsed is updated
1410	 * under page_cgroup lock: between them, they make all uses
1411	 * of pc->mem_cgroup safe.
1412	 */
1413	if (!PageLRU(page) && !PageCgroupUsed(pc) && memcg != root_mem_cgroup)
1414		pc->mem_cgroup = memcg = root_mem_cgroup;
 
 
 
 
 
 
 
 
 
 
1415
1416	mz = page_cgroup_zoneinfo(memcg, page);
1417	lruvec = &mz->lruvec;
1418out:
1419	/*
1420	 * Since a node can be onlined after the mem_cgroup was created,
1421	 * we have to be prepared to initialize lruvec->zone here;
1422	 * and if offlined then reonlined, we need to reinitialize it.
1423	 */
1424	if (unlikely(lruvec->zone != zone))
1425		lruvec->zone = zone;
1426	return lruvec;
1427}
1428
1429/**
1430 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1431 * @lruvec: mem_cgroup per zone lru vector
1432 * @lru: index of lru list the page is sitting on
 
1433 * @nr_pages: positive when adding or negative when removing
1434 *
1435 * This function must be called when a page is added to or removed from an
1436 * lru list.
1437 */
1438void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
1439				int nr_pages)
1440{
1441	struct mem_cgroup_per_zone *mz;
1442	unsigned long *lru_size;
 
1443
1444	if (mem_cgroup_disabled())
1445		return;
1446
1447	mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
1448	lru_size = mz->lru_size + lru;
1449	*lru_size += nr_pages;
1450	VM_BUG_ON((long)(*lru_size) < 0);
1451}
1452
1453/*
1454 * Checks whether given mem is same or in the root_mem_cgroup's
1455 * hierarchy subtree
1456 */
1457bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
1458				  struct mem_cgroup *memcg)
1459{
1460	if (root_memcg == memcg)
1461		return true;
1462	if (!root_memcg->use_hierarchy || !memcg)
1463		return false;
1464	return cgroup_is_descendant(memcg->css.cgroup, root_memcg->css.cgroup);
1465}
1466
1467static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
1468				       struct mem_cgroup *memcg)
1469{
1470	bool ret;
1471
1472	rcu_read_lock();
1473	ret = __mem_cgroup_same_or_subtree(root_memcg, memcg);
1474	rcu_read_unlock();
1475	return ret;
1476}
1477
1478bool task_in_mem_cgroup(struct task_struct *task,
1479			const struct mem_cgroup *memcg)
1480{
1481	struct mem_cgroup *curr = NULL;
1482	struct task_struct *p;
1483	bool ret;
1484
1485	p = find_lock_task_mm(task);
1486	if (p) {
1487		curr = get_mem_cgroup_from_mm(p->mm);
1488		task_unlock(p);
1489	} else {
1490		/*
1491		 * All threads may have already detached their mm's, but the oom
1492		 * killer still needs to detect if they have already been oom
1493		 * killed to prevent needlessly killing additional tasks.
1494		 */
1495		rcu_read_lock();
1496		curr = mem_cgroup_from_task(task);
1497		if (curr)
1498			css_get(&curr->css);
1499		rcu_read_unlock();
1500	}
1501	/*
1502	 * We should check use_hierarchy of "memcg" not "curr". Because checking
1503	 * use_hierarchy of "curr" here make this function true if hierarchy is
1504	 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
1505	 * hierarchy(even if use_hierarchy is disabled in "memcg").
1506	 */
1507	ret = mem_cgroup_same_or_subtree(memcg, curr);
1508	css_put(&curr->css);
1509	return ret;
1510}
1511
1512int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
1513{
1514	unsigned long inactive_ratio;
1515	unsigned long inactive;
1516	unsigned long active;
1517	unsigned long gb;
1518
1519	inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON);
1520	active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON);
1521
1522	gb = (inactive + active) >> (30 - PAGE_SHIFT);
1523	if (gb)
1524		inactive_ratio = int_sqrt(10 * gb);
1525	else
1526		inactive_ratio = 1;
1527
1528	return inactive * inactive_ratio < active;
1529}
1530
1531#define mem_cgroup_from_res_counter(counter, member)	\
1532	container_of(counter, struct mem_cgroup, member)
1533
1534/**
1535 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1536 * @memcg: the memory cgroup
1537 *
1538 * Returns the maximum amount of memory @mem can be charged with, in
1539 * pages.
1540 */
1541static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
1542{
1543	unsigned long long margin;
1544
1545	margin = res_counter_margin(&memcg->res);
1546	if (do_swap_account)
1547		margin = min(margin, res_counter_margin(&memcg->memsw));
1548	return margin >> PAGE_SHIFT;
1549}
1550
1551int mem_cgroup_swappiness(struct mem_cgroup *memcg)
1552{
1553	/* root ? */
1554	if (!css_parent(&memcg->css))
1555		return vm_swappiness;
1556
1557	return memcg->swappiness;
1558}
1559
1560/*
1561 * memcg->moving_account is used for checking possibility that some thread is
1562 * calling move_account(). When a thread on CPU-A starts moving pages under
1563 * a memcg, other threads should check memcg->moving_account under
1564 * rcu_read_lock(), like this:
1565 *
1566 *         CPU-A                                    CPU-B
1567 *                                              rcu_read_lock()
1568 *         memcg->moving_account+1              if (memcg->mocing_account)
1569 *                                                   take heavy locks.
1570 *         synchronize_rcu()                    update something.
1571 *                                              rcu_read_unlock()
1572 *         start move here.
1573 */
1574
1575/* for quick checking without looking up memcg */
1576atomic_t memcg_moving __read_mostly;
1577
1578static void mem_cgroup_start_move(struct mem_cgroup *memcg)
1579{
1580	atomic_inc(&memcg_moving);
1581	atomic_inc(&memcg->moving_account);
1582	synchronize_rcu();
1583}
1584
1585static void mem_cgroup_end_move(struct mem_cgroup *memcg)
1586{
1587	/*
1588	 * Now, mem_cgroup_clear_mc() may call this function with NULL.
1589	 * We check NULL in callee rather than caller.
1590	 */
1591	if (memcg) {
1592		atomic_dec(&memcg_moving);
1593		atomic_dec(&memcg->moving_account);
1594	}
 
 
1595}
1596
1597/*
1598 * 2 routines for checking "mem" is under move_account() or not.
1599 *
1600 * mem_cgroup_stolen() -  checking whether a cgroup is mc.from or not. This
1601 *			  is used for avoiding races in accounting.  If true,
1602 *			  pc->mem_cgroup may be overwritten.
1603 *
1604 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1605 *			  under hierarchy of moving cgroups. This is for
1606 *			  waiting at hith-memory prressure caused by "move".
1607 */
1608
1609static bool mem_cgroup_stolen(struct mem_cgroup *memcg)
1610{
1611	VM_BUG_ON(!rcu_read_lock_held());
1612	return atomic_read(&memcg->moving_account) > 0;
1613}
1614
1615static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
1616{
1617	struct mem_cgroup *from;
1618	struct mem_cgroup *to;
1619	bool ret = false;
1620	/*
1621	 * Unlike task_move routines, we access mc.to, mc.from not under
1622	 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1623	 */
1624	spin_lock(&mc.lock);
1625	from = mc.from;
1626	to = mc.to;
1627	if (!from)
1628		goto unlock;
1629
1630	ret = mem_cgroup_same_or_subtree(memcg, from)
1631		|| mem_cgroup_same_or_subtree(memcg, to);
1632unlock:
1633	spin_unlock(&mc.lock);
1634	return ret;
1635}
1636
1637static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
1638{
1639	if (mc.moving_task && current != mc.moving_task) {
1640		if (mem_cgroup_under_move(memcg)) {
1641			DEFINE_WAIT(wait);
1642			prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1643			/* moving charge context might have finished. */
1644			if (mc.moving_task)
1645				schedule();
1646			finish_wait(&mc.waitq, &wait);
1647			return true;
1648		}
1649	}
1650	return false;
1651}
1652
1653/*
1654 * Take this lock when
1655 * - a code tries to modify page's memcg while it's USED.
1656 * - a code tries to modify page state accounting in a memcg.
1657 * see mem_cgroup_stolen(), too.
1658 */
1659static void move_lock_mem_cgroup(struct mem_cgroup *memcg,
1660				  unsigned long *flags)
1661{
1662	spin_lock_irqsave(&memcg->move_lock, *flags);
1663}
1664
1665static void move_unlock_mem_cgroup(struct mem_cgroup *memcg,
1666				unsigned long *flags)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1667{
1668	spin_unlock_irqrestore(&memcg->move_lock, *flags);
 
 
 
 
 
 
 
 
 
 
1669}
1670
1671#define K(x) ((x) << (PAGE_SHIFT-10))
1672/**
1673 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1674 * @memcg: The memory cgroup that went over limit
1675 * @p: Task that is going to be killed
1676 *
1677 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1678 * enabled
1679 */
1680void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1681{
1682	/* oom_info_lock ensures that parallel ooms do not interleave */
1683	static DEFINE_MUTEX(oom_info_lock);
1684	struct mem_cgroup *iter;
1685	unsigned int i;
1686
1687	if (!p)
1688		return;
1689
1690	mutex_lock(&oom_info_lock);
1691	rcu_read_lock();
1692
1693	pr_info("Task in ");
1694	pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
1695	pr_info(" killed as a result of limit of ");
1696	pr_cont_cgroup_path(memcg->css.cgroup);
1697	pr_info("\n");
1698
1699	rcu_read_unlock();
1700
1701	pr_info("memory: usage %llukB, limit %llukB, failcnt %llu\n",
1702		res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1703		res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1704		res_counter_read_u64(&memcg->res, RES_FAILCNT));
1705	pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %llu\n",
1706		res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1707		res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1708		res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
1709	pr_info("kmem: usage %llukB, limit %llukB, failcnt %llu\n",
1710		res_counter_read_u64(&memcg->kmem, RES_USAGE) >> 10,
1711		res_counter_read_u64(&memcg->kmem, RES_LIMIT) >> 10,
1712		res_counter_read_u64(&memcg->kmem, RES_FAILCNT));
1713
1714	for_each_mem_cgroup_tree(iter, memcg) {
1715		pr_info("Memory cgroup stats for ");
1716		pr_cont_cgroup_path(iter->css.cgroup);
1717		pr_cont(":");
1718
1719		for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
1720			if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
1721				continue;
1722			pr_cont(" %s:%ldKB", mem_cgroup_stat_names[i],
1723				K(mem_cgroup_read_stat(iter, i)));
1724		}
1725
1726		for (i = 0; i < NR_LRU_LISTS; i++)
1727			pr_cont(" %s:%luKB", mem_cgroup_lru_names[i],
1728				K(mem_cgroup_nr_lru_pages(iter, BIT(i))));
1729
1730		pr_cont("\n");
1731	}
1732	mutex_unlock(&oom_info_lock);
1733}
1734
1735/*
1736 * This function returns the number of memcg under hierarchy tree. Returns
1737 * 1(self count) if no children.
1738 */
1739static int mem_cgroup_count_children(struct mem_cgroup *memcg)
1740{
1741	int num = 0;
1742	struct mem_cgroup *iter;
1743
1744	for_each_mem_cgroup_tree(iter, memcg)
1745		num++;
1746	return num;
1747}
1748
1749/*
1750 * Return the memory (and swap, if configured) limit for a memcg.
1751 */
1752static u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
1753{
1754	u64 limit;
1755
1756	limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
1757
1758	/*
1759	 * Do not consider swap space if we cannot swap due to swappiness
1760	 */
1761	if (mem_cgroup_swappiness(memcg)) {
1762		u64 memsw;
1763
1764		limit += total_swap_pages << PAGE_SHIFT;
1765		memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1766
1767		/*
1768		 * If memsw is finite and limits the amount of swap space
1769		 * available to this memcg, return that limit.
1770		 */
1771		limit = min(limit, memsw);
1772	}
1773
1774	return limit;
1775}
1776
1777static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
1778				     int order)
1779{
1780	struct mem_cgroup *iter;
1781	unsigned long chosen_points = 0;
1782	unsigned long totalpages;
1783	unsigned int points = 0;
1784	struct task_struct *chosen = NULL;
1785
1786	/*
1787	 * If current has a pending SIGKILL or is exiting, then automatically
1788	 * select it.  The goal is to allow it to allocate so that it may
1789	 * quickly exit and free its memory.
 
 
 
 
 
1790	 */
1791	if (fatal_signal_pending(current) || current->flags & PF_EXITING) {
1792		set_thread_flag(TIF_MEMDIE);
1793		return;
1794	}
1795
1796	check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL);
1797	totalpages = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT ? : 1;
1798	for_each_mem_cgroup_tree(iter, memcg) {
1799		struct css_task_iter it;
1800		struct task_struct *task;
1801
1802		css_task_iter_start(&iter->css, &it);
1803		while ((task = css_task_iter_next(&it))) {
1804			switch (oom_scan_process_thread(task, totalpages, NULL,
1805							false)) {
1806			case OOM_SCAN_SELECT:
1807				if (chosen)
1808					put_task_struct(chosen);
1809				chosen = task;
1810				chosen_points = ULONG_MAX;
1811				get_task_struct(chosen);
1812				/* fall through */
1813			case OOM_SCAN_CONTINUE:
1814				continue;
1815			case OOM_SCAN_ABORT:
1816				css_task_iter_end(&it);
1817				mem_cgroup_iter_break(memcg, iter);
1818				if (chosen)
1819					put_task_struct(chosen);
1820				return;
1821			case OOM_SCAN_OK:
1822				break;
1823			};
1824			points = oom_badness(task, memcg, NULL, totalpages);
1825			if (!points || points < chosen_points)
1826				continue;
1827			/* Prefer thread group leaders for display purposes */
1828			if (points == chosen_points &&
1829			    thread_group_leader(chosen))
1830				continue;
1831
1832			if (chosen)
1833				put_task_struct(chosen);
1834			chosen = task;
1835			chosen_points = points;
1836			get_task_struct(chosen);
1837		}
1838		css_task_iter_end(&it);
1839	}
1840
1841	if (!chosen)
1842		return;
1843	points = chosen_points * 1000 / totalpages;
1844	oom_kill_process(chosen, gfp_mask, order, points, totalpages, memcg,
1845			 NULL, "Memory cgroup out of memory");
1846}
1847
1848static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg,
1849					gfp_t gfp_mask,
1850					unsigned long flags)
1851{
1852	unsigned long total = 0;
1853	bool noswap = false;
1854	int loop;
1855
1856	if (flags & MEM_CGROUP_RECLAIM_NOSWAP)
1857		noswap = true;
1858	if (!(flags & MEM_CGROUP_RECLAIM_SHRINK) && memcg->memsw_is_minimum)
1859		noswap = true;
1860
1861	for (loop = 0; loop < MEM_CGROUP_MAX_RECLAIM_LOOPS; loop++) {
1862		if (loop)
1863			drain_all_stock_async(memcg);
1864		total += try_to_free_mem_cgroup_pages(memcg, gfp_mask, noswap);
1865		/*
1866		 * Allow limit shrinkers, which are triggered directly
1867		 * by userspace, to catch signals and stop reclaim
1868		 * after minimal progress, regardless of the margin.
1869		 */
1870		if (total && (flags & MEM_CGROUP_RECLAIM_SHRINK))
1871			break;
1872		if (mem_cgroup_margin(memcg))
1873			break;
1874		/*
1875		 * If nothing was reclaimed after two attempts, there
1876		 * may be no reclaimable pages in this hierarchy.
1877		 */
1878		if (loop && !total)
1879			break;
1880	}
1881	return total;
 
 
1882}
1883
1884/**
1885 * test_mem_cgroup_node_reclaimable
1886 * @memcg: the target memcg
1887 * @nid: the node ID to be checked.
1888 * @noswap : specify true here if the user wants flle only information.
1889 *
1890 * This function returns whether the specified memcg contains any
1891 * reclaimable pages on a node. Returns true if there are any reclaimable
1892 * pages in the node.
1893 */
1894static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
1895		int nid, bool noswap)
1896{
1897	if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
1898		return true;
1899	if (noswap || !total_swap_pages)
1900		return false;
1901	if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
1902		return true;
1903	return false;
1904
 
 
 
 
 
 
 
1905}
1906#if MAX_NUMNODES > 1
1907
1908/*
1909 * Always updating the nodemask is not very good - even if we have an empty
1910 * list or the wrong list here, we can start from some node and traverse all
1911 * nodes based on the zonelist. So update the list loosely once per 10 secs.
 
1912 *
 
 
1913 */
1914static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
1915{
1916	int nid;
1917	/*
1918	 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1919	 * pagein/pageout changes since the last update.
1920	 */
1921	if (!atomic_read(&memcg->numainfo_events))
1922		return;
1923	if (atomic_inc_return(&memcg->numainfo_updating) > 1)
1924		return;
1925
1926	/* make a nodemask where this memcg uses memory from */
1927	memcg->scan_nodes = node_states[N_MEMORY];
1928
1929	for_each_node_mask(nid, node_states[N_MEMORY]) {
1930
1931		if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
1932			node_clear(nid, memcg->scan_nodes);
 
 
 
 
 
 
1933	}
1934
1935	atomic_set(&memcg->numainfo_events, 0);
1936	atomic_set(&memcg->numainfo_updating, 0);
1937}
1938
1939/*
1940 * Selecting a node where we start reclaim from. Because what we need is just
1941 * reducing usage counter, start from anywhere is O,K. Considering
1942 * memory reclaim from current node, there are pros. and cons.
1943 *
1944 * Freeing memory from current node means freeing memory from a node which
1945 * we'll use or we've used. So, it may make LRU bad. And if several threads
1946 * hit limits, it will see a contention on a node. But freeing from remote
1947 * node means more costs for memory reclaim because of memory latency.
1948 *
1949 * Now, we use round-robin. Better algorithm is welcomed.
1950 */
1951int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1952{
1953	int node;
1954
1955	mem_cgroup_may_update_nodemask(memcg);
1956	node = memcg->last_scanned_node;
1957
1958	node = next_node(node, memcg->scan_nodes);
1959	if (node == MAX_NUMNODES)
1960		node = first_node(memcg->scan_nodes);
1961	/*
1962	 * We call this when we hit limit, not when pages are added to LRU.
1963	 * No LRU may hold pages because all pages are UNEVICTABLE or
1964	 * memcg is too small and all pages are not on LRU. In that case,
1965	 * we use curret node.
1966	 */
1967	if (unlikely(node == MAX_NUMNODES))
1968		node = numa_node_id();
 
 
 
 
 
1969
1970	memcg->last_scanned_node = node;
1971	return node;
 
 
 
 
1972}
1973
1974/*
1975 * Check all nodes whether it contains reclaimable pages or not.
1976 * For quick scan, we make use of scan_nodes. This will allow us to skip
1977 * unused nodes. But scan_nodes is lazily updated and may not cotain
1978 * enough new information. We need to do double check.
1979 */
1980static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
1981{
1982	int nid;
1983
1984	/*
1985	 * quick check...making use of scan_node.
1986	 * We can skip unused nodes.
1987	 */
1988	if (!nodes_empty(memcg->scan_nodes)) {
1989		for (nid = first_node(memcg->scan_nodes);
1990		     nid < MAX_NUMNODES;
1991		     nid = next_node(nid, memcg->scan_nodes)) {
1992
1993			if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
1994				return true;
1995		}
 
 
 
 
1996	}
1997	/*
1998	 * Check rest of nodes.
1999	 */
2000	for_each_node_state(nid, N_MEMORY) {
2001		if (node_isset(nid, memcg->scan_nodes))
2002			continue;
2003		if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
2004			return true;
2005	}
2006	return false;
2007}
2008
2009#else
2010int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
2011{
2012	return 0;
2013}
2014
2015static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
 
2016{
2017	return test_mem_cgroup_node_reclaimable(memcg, 0, noswap);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2018}
2019#endif
2020
2021static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
2022				   struct zone *zone,
2023				   gfp_t gfp_mask,
2024				   unsigned long *total_scanned)
2025{
2026	struct mem_cgroup *victim = NULL;
2027	int total = 0;
2028	int loop = 0;
2029	unsigned long excess;
2030	unsigned long nr_scanned;
2031	struct mem_cgroup_reclaim_cookie reclaim = {
2032		.zone = zone,
2033		.priority = 0,
2034	};
2035
2036	excess = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT;
2037
2038	while (1) {
2039		victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
2040		if (!victim) {
2041			loop++;
2042			if (loop >= 2) {
2043				/*
2044				 * If we have not been able to reclaim
2045				 * anything, it might because there are
2046				 * no reclaimable pages under this hierarchy
2047				 */
2048				if (!total)
2049					break;
2050				/*
2051				 * We want to do more targeted reclaim.
2052				 * excess >> 2 is not to excessive so as to
2053				 * reclaim too much, nor too less that we keep
2054				 * coming back to reclaim from this cgroup
2055				 */
2056				if (total >= (excess >> 2) ||
2057					(loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
2058					break;
2059			}
2060			continue;
2061		}
2062		if (!mem_cgroup_reclaimable(victim, false))
2063			continue;
2064		total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false,
2065						     zone, &nr_scanned);
2066		*total_scanned += nr_scanned;
2067		if (!res_counter_soft_limit_excess(&root_memcg->res))
2068			break;
2069	}
2070	mem_cgroup_iter_break(root_memcg, victim);
2071	return total;
2072}
2073
2074#ifdef CONFIG_LOCKDEP
2075static struct lockdep_map memcg_oom_lock_dep_map = {
2076	.name = "memcg_oom_lock",
2077};
2078#endif
2079
2080static DEFINE_SPINLOCK(memcg_oom_lock);
2081
2082/*
2083 * Check OOM-Killer is already running under our hierarchy.
2084 * If someone is running, return false.
2085 */
2086static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg)
2087{
2088	struct mem_cgroup *iter, *failed = NULL;
2089
2090	spin_lock(&memcg_oom_lock);
2091
2092	for_each_mem_cgroup_tree(iter, memcg) {
2093		if (iter->oom_lock) {
2094			/*
2095			 * this subtree of our hierarchy is already locked
2096			 * so we cannot give a lock.
2097			 */
2098			failed = iter;
2099			mem_cgroup_iter_break(memcg, iter);
2100			break;
2101		} else
2102			iter->oom_lock = true;
2103	}
2104
2105	if (failed) {
2106		/*
2107		 * OK, we failed to lock the whole subtree so we have
2108		 * to clean up what we set up to the failing subtree
2109		 */
2110		for_each_mem_cgroup_tree(iter, memcg) {
2111			if (iter == failed) {
2112				mem_cgroup_iter_break(memcg, iter);
2113				break;
2114			}
2115			iter->oom_lock = false;
2116		}
2117	} else
2118		mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_);
2119
2120	spin_unlock(&memcg_oom_lock);
2121
2122	return !failed;
2123}
2124
2125static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
2126{
2127	struct mem_cgroup *iter;
2128
2129	spin_lock(&memcg_oom_lock);
2130	mutex_release(&memcg_oom_lock_dep_map, 1, _RET_IP_);
2131	for_each_mem_cgroup_tree(iter, memcg)
2132		iter->oom_lock = false;
2133	spin_unlock(&memcg_oom_lock);
2134}
2135
2136static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
2137{
2138	struct mem_cgroup *iter;
2139
 
2140	for_each_mem_cgroup_tree(iter, memcg)
2141		atomic_inc(&iter->under_oom);
 
2142}
2143
2144static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
2145{
2146	struct mem_cgroup *iter;
2147
2148	/*
2149	 * When a new child is created while the hierarchy is under oom,
2150	 * mem_cgroup_oom_lock() may not be called. We have to use
2151	 * atomic_add_unless() here.
2152	 */
 
2153	for_each_mem_cgroup_tree(iter, memcg)
2154		atomic_add_unless(&iter->under_oom, -1, 0);
 
 
2155}
2156
2157static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
2158
2159struct oom_wait_info {
2160	struct mem_cgroup *memcg;
2161	wait_queue_t	wait;
2162};
2163
2164static int memcg_oom_wake_function(wait_queue_t *wait,
2165	unsigned mode, int sync, void *arg)
2166{
2167	struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
2168	struct mem_cgroup *oom_wait_memcg;
2169	struct oom_wait_info *oom_wait_info;
2170
2171	oom_wait_info = container_of(wait, struct oom_wait_info, wait);
2172	oom_wait_memcg = oom_wait_info->memcg;
2173
2174	/*
2175	 * Both of oom_wait_info->memcg and wake_memcg are stable under us.
2176	 * Then we can use css_is_ancestor without taking care of RCU.
2177	 */
2178	if (!mem_cgroup_same_or_subtree(oom_wait_memcg, wake_memcg)
2179		&& !mem_cgroup_same_or_subtree(wake_memcg, oom_wait_memcg))
2180		return 0;
2181	return autoremove_wake_function(wait, mode, sync, arg);
2182}
2183
2184static void memcg_wakeup_oom(struct mem_cgroup *memcg)
2185{
2186	atomic_inc(&memcg->oom_wakeups);
2187	/* for filtering, pass "memcg" as argument. */
2188	__wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
2189}
2190
2191static void memcg_oom_recover(struct mem_cgroup *memcg)
2192{
2193	if (memcg && atomic_read(&memcg->under_oom))
2194		memcg_wakeup_oom(memcg);
 
 
 
 
 
 
 
 
2195}
2196
2197static void mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
 
 
 
 
2198{
2199	if (!current->memcg_oom.may_oom)
2200		return;
 
 
 
 
 
2201	/*
2202	 * We are in the middle of the charge context here, so we
2203	 * don't want to block when potentially sitting on a callstack
2204	 * that holds all kinds of filesystem and mm locks.
2205	 *
2206	 * Also, the caller may handle a failed allocation gracefully
2207	 * (like optional page cache readahead) and so an OOM killer
2208	 * invocation might not even be necessary.
 
2209	 *
2210	 * That's why we don't do anything here except remember the
2211	 * OOM context and then deal with it at the end of the page
2212	 * fault when the stack is unwound, the locks are released,
2213	 * and when we know whether the fault was overall successful.
 
 
 
2214	 */
2215	css_get(&memcg->css);
2216	current->memcg_oom.memcg = memcg;
2217	current->memcg_oom.gfp_mask = mask;
2218	current->memcg_oom.order = order;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2219}
2220
2221/**
2222 * mem_cgroup_oom_synchronize - complete memcg OOM handling
2223 * @handle: actually kill/wait or just clean up the OOM state
2224 *
2225 * This has to be called at the end of a page fault if the memcg OOM
2226 * handler was enabled.
2227 *
2228 * Memcg supports userspace OOM handling where failed allocations must
2229 * sleep on a waitqueue until the userspace task resolves the
2230 * situation.  Sleeping directly in the charge context with all kinds
2231 * of locks held is not a good idea, instead we remember an OOM state
2232 * in the task and mem_cgroup_oom_synchronize() has to be called at
2233 * the end of the page fault to complete the OOM handling.
2234 *
2235 * Returns %true if an ongoing memcg OOM situation was detected and
2236 * completed, %false otherwise.
2237 */
2238bool mem_cgroup_oom_synchronize(bool handle)
2239{
2240	struct mem_cgroup *memcg = current->memcg_oom.memcg;
2241	struct oom_wait_info owait;
2242	bool locked;
2243
2244	/* OOM is global, do not handle */
2245	if (!memcg)
2246		return false;
2247
2248	if (!handle)
2249		goto cleanup;
2250
2251	owait.memcg = memcg;
2252	owait.wait.flags = 0;
2253	owait.wait.func = memcg_oom_wake_function;
2254	owait.wait.private = current;
2255	INIT_LIST_HEAD(&owait.wait.task_list);
2256
2257	prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
2258	mem_cgroup_mark_under_oom(memcg);
2259
2260	locked = mem_cgroup_oom_trylock(memcg);
2261
2262	if (locked)
2263		mem_cgroup_oom_notify(memcg);
2264
2265	if (locked && !memcg->oom_kill_disable) {
2266		mem_cgroup_unmark_under_oom(memcg);
2267		finish_wait(&memcg_oom_waitq, &owait.wait);
2268		mem_cgroup_out_of_memory(memcg, current->memcg_oom.gfp_mask,
2269					 current->memcg_oom.order);
2270	} else {
2271		schedule();
2272		mem_cgroup_unmark_under_oom(memcg);
2273		finish_wait(&memcg_oom_waitq, &owait.wait);
2274	}
2275
2276	if (locked) {
2277		mem_cgroup_oom_unlock(memcg);
2278		/*
2279		 * There is no guarantee that an OOM-lock contender
2280		 * sees the wakeups triggered by the OOM kill
2281		 * uncharges.  Wake any sleepers explicitely.
2282		 */
2283		memcg_oom_recover(memcg);
2284	}
2285cleanup:
2286	current->memcg_oom.memcg = NULL;
2287	css_put(&memcg->css);
2288	return true;
2289}
2290
2291/*
2292 * Currently used to update mapped file statistics, but the routine can be
2293 * generalized to update other statistics as well.
2294 *
2295 * Notes: Race condition
2296 *
2297 * We usually use page_cgroup_lock() for accessing page_cgroup member but
2298 * it tends to be costly. But considering some conditions, we doesn't need
2299 * to do so _always_.
2300 *
2301 * Considering "charge", lock_page_cgroup() is not required because all
2302 * file-stat operations happen after a page is attached to radix-tree. There
2303 * are no race with "charge".
2304 *
2305 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
2306 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
2307 * if there are race with "uncharge". Statistics itself is properly handled
2308 * by flags.
2309 *
2310 * Considering "move", this is an only case we see a race. To make the race
2311 * small, we check mm->moving_account and detect there are possibility of race
2312 * If there is, we take a lock.
2313 */
2314
2315void __mem_cgroup_begin_update_page_stat(struct page *page,
2316				bool *locked, unsigned long *flags)
2317{
 
2318	struct mem_cgroup *memcg;
2319	struct page_cgroup *pc;
2320
2321	pc = lookup_page_cgroup(page);
2322again:
2323	memcg = pc->mem_cgroup;
2324	if (unlikely(!memcg || !PageCgroupUsed(pc)))
2325		return;
 
 
 
 
 
 
 
2326	/*
2327	 * If this memory cgroup is not under account moving, we don't
2328	 * need to take move_lock_mem_cgroup(). Because we already hold
2329	 * rcu_read_lock(), any calls to move_account will be delayed until
2330	 * rcu_read_unlock() if mem_cgroup_stolen() == true.
2331	 */
2332	if (!mem_cgroup_stolen(memcg))
2333		return;
2334
2335	move_lock_mem_cgroup(memcg, flags);
2336	if (memcg != pc->mem_cgroup || !PageCgroupUsed(pc)) {
2337		move_unlock_mem_cgroup(memcg, flags);
2338		goto again;
 
 
 
 
 
 
 
2339	}
2340	*locked = true;
 
 
 
 
 
 
2341}
2342
2343void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags)
2344{
2345	struct page_cgroup *pc = lookup_page_cgroup(page);
2346
2347	/*
2348	 * It's guaranteed that pc->mem_cgroup never changes while
2349	 * lock is held because a routine modifies pc->mem_cgroup
2350	 * should take move_lock_mem_cgroup().
2351	 */
2352	move_unlock_mem_cgroup(pc->mem_cgroup, flags);
2353}
2354
2355void mem_cgroup_update_page_stat(struct page *page,
2356				 enum mem_cgroup_stat_index idx, int val)
 
 
 
 
 
 
 
 
 
2357{
2358	struct mem_cgroup *memcg;
2359	struct page_cgroup *pc = lookup_page_cgroup(page);
2360	unsigned long uninitialized_var(flags);
 
 
 
 
 
 
2361
2362	if (mem_cgroup_disabled())
2363		return;
 
 
 
 
 
 
 
 
 
 
2364
2365	VM_BUG_ON(!rcu_read_lock_held());
2366	memcg = pc->mem_cgroup;
2367	if (unlikely(!memcg || !PageCgroupUsed(pc)))
2368		return;
2369
2370	this_cpu_add(memcg->stat->count[idx], val);
 
 
 
 
 
 
 
 
 
 
 
 
 
2371}
2372
2373/*
2374 * size of first charge trial. "32" comes from vmscan.c's magic value.
2375 * TODO: maybe necessary to use big numbers in big irons.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2376 */
2377#define CHARGE_BATCH	32U
 
 
 
 
2378struct memcg_stock_pcp {
 
2379	struct mem_cgroup *cached; /* this never be root cgroup */
2380	unsigned int nr_pages;
 
 
 
 
 
 
 
 
 
2381	struct work_struct work;
2382	unsigned long flags;
2383#define FLUSHING_CACHED_CHARGE	0
2384};
2385static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
 
 
2386static DEFINE_MUTEX(percpu_charge_mutex);
2387
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2388/**
2389 * consume_stock: Try to consume stocked charge on this cpu.
2390 * @memcg: memcg to consume from.
2391 * @nr_pages: how many pages to charge.
2392 *
2393 * The charges will only happen if @memcg matches the current cpu's memcg
2394 * stock, and at least @nr_pages are available in that stock.  Failure to
2395 * service an allocation will refill the stock.
2396 *
2397 * returns true if successful, false otherwise.
2398 */
2399static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2400{
2401	struct memcg_stock_pcp *stock;
2402	bool ret = true;
 
2403
2404	if (nr_pages > CHARGE_BATCH)
2405		return false;
 
 
2406
2407	stock = &get_cpu_var(memcg_stock);
2408	if (memcg == stock->cached && stock->nr_pages >= nr_pages)
2409		stock->nr_pages -= nr_pages;
2410	else /* need to call res_counter_charge */
2411		ret = false;
2412	put_cpu_var(memcg_stock);
 
 
2413	return ret;
2414}
2415
2416/*
2417 * Returns stocks cached in percpu to res_counter and reset cached information.
2418 */
2419static void drain_stock(struct memcg_stock_pcp *stock)
2420{
2421	struct mem_cgroup *old = stock->cached;
2422
2423	if (stock->nr_pages) {
2424		unsigned long bytes = stock->nr_pages * PAGE_SIZE;
2425
2426		res_counter_uncharge(&old->res, bytes);
2427		if (do_swap_account)
2428			res_counter_uncharge(&old->memsw, bytes);
 
2429		stock->nr_pages = 0;
2430	}
2431	stock->cached = NULL;
 
 
2432}
2433
2434/*
2435 * This must be called under preempt disabled or must be called by
2436 * a thread which is pinned to local cpu.
2437 */
2438static void drain_local_stock(struct work_struct *dummy)
2439{
2440	struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock);
 
 
 
 
 
 
 
 
 
 
 
 
2441	drain_stock(stock);
2442	clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2443}
2444
2445static void __init memcg_stock_init(void)
2446{
2447	int cpu;
2448
2449	for_each_possible_cpu(cpu) {
2450		struct memcg_stock_pcp *stock =
2451					&per_cpu(memcg_stock, cpu);
2452		INIT_WORK(&stock->work, drain_local_stock);
2453	}
2454}
2455
2456/*
2457 * Cache charges(val) which is from res_counter, to local per_cpu area.
2458 * This will be consumed by consume_stock() function, later.
2459 */
2460static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2461{
2462	struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
2463
2464	if (stock->cached != memcg) { /* reset if necessary */
 
2465		drain_stock(stock);
2466		stock->cached = memcg;
 
2467	}
2468	stock->nr_pages += nr_pages;
2469	put_cpu_var(memcg_stock);
 
 
 
 
 
 
 
 
 
 
 
2470}
2471
2472/*
2473 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2474 * of the hierarchy under it. sync flag says whether we should block
2475 * until the work is done.
2476 */
2477static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync)
2478{
2479	int cpu, curcpu;
2480
2481	/* Notify other cpus that system-wide "drain" is running */
2482	get_online_cpus();
2483	curcpu = get_cpu();
 
 
 
 
 
 
 
 
2484	for_each_online_cpu(cpu) {
2485		struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2486		struct mem_cgroup *memcg;
 
2487
2488		memcg = stock->cached;
2489		if (!memcg || !stock->nr_pages)
2490			continue;
2491		if (!mem_cgroup_same_or_subtree(root_memcg, memcg))
2492			continue;
2493		if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
 
 
 
 
 
2494			if (cpu == curcpu)
2495				drain_local_stock(&stock->work);
2496			else
2497				schedule_work_on(cpu, &stock->work);
2498		}
2499	}
2500	put_cpu();
2501
2502	if (!sync)
2503		goto out;
2504
2505	for_each_online_cpu(cpu) {
2506		struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2507		if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
2508			flush_work(&stock->work);
2509	}
2510out:
2511	put_online_cpus();
2512}
2513
2514/*
2515 * Tries to drain stocked charges in other cpus. This function is asynchronous
2516 * and just put a work per cpu for draining localy on each cpu. Caller can
2517 * expects some charges will be back to res_counter later but cannot wait for
2518 * it.
2519 */
2520static void drain_all_stock_async(struct mem_cgroup *root_memcg)
2521{
2522	/*
2523	 * If someone calls draining, avoid adding more kworker runs.
2524	 */
2525	if (!mutex_trylock(&percpu_charge_mutex))
2526		return;
2527	drain_all_stock(root_memcg, false);
2528	mutex_unlock(&percpu_charge_mutex);
2529}
2530
2531/* This is a synchronous drain interface. */
2532static void drain_all_stock_sync(struct mem_cgroup *root_memcg)
2533{
2534	/* called when force_empty is called */
2535	mutex_lock(&percpu_charge_mutex);
2536	drain_all_stock(root_memcg, true);
2537	mutex_unlock(&percpu_charge_mutex);
2538}
2539
2540/*
2541 * This function drains percpu counter value from DEAD cpu and
2542 * move it to local cpu. Note that this function can be preempted.
2543 */
2544static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu)
2545{
2546	int i;
2547
2548	spin_lock(&memcg->pcp_counter_lock);
2549	for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
2550		long x = per_cpu(memcg->stat->count[i], cpu);
2551
2552		per_cpu(memcg->stat->count[i], cpu) = 0;
2553		memcg->nocpu_base.count[i] += x;
2554	}
2555	for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
2556		unsigned long x = per_cpu(memcg->stat->events[i], cpu);
2557
2558		per_cpu(memcg->stat->events[i], cpu) = 0;
2559		memcg->nocpu_base.events[i] += x;
2560	}
2561	spin_unlock(&memcg->pcp_counter_lock);
2562}
2563
2564static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
2565					unsigned long action,
2566					void *hcpu)
2567{
2568	int cpu = (unsigned long)hcpu;
2569	struct memcg_stock_pcp *stock;
2570	struct mem_cgroup *iter;
2571
2572	if (action == CPU_ONLINE)
2573		return NOTIFY_OK;
2574
2575	if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
2576		return NOTIFY_OK;
 
2577
2578	for_each_mem_cgroup(iter)
2579		mem_cgroup_drain_pcp_counter(iter, cpu);
2580
2581	stock = &per_cpu(memcg_stock, cpu);
2582	drain_stock(stock);
2583	return NOTIFY_OK;
2584}
2585
 
 
 
 
 
 
 
2586
2587/* See mem_cgroup_try_charge() for details */
2588enum {
2589	CHARGE_OK,		/* success */
2590	CHARGE_RETRY,		/* need to retry but retry is not bad */
2591	CHARGE_NOMEM,		/* we can't do more. return -ENOMEM */
2592	CHARGE_WOULDBLOCK,	/* GFP_WAIT wasn't set and no enough res. */
2593};
2594
2595static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
2596				unsigned int nr_pages, unsigned int min_pages,
2597				bool invoke_oom)
2598{
2599	unsigned long csize = nr_pages * PAGE_SIZE;
2600	struct mem_cgroup *mem_over_limit;
2601	struct res_counter *fail_res;
2602	unsigned long flags = 0;
2603	int ret;
2604
2605	ret = res_counter_charge(&memcg->res, csize, &fail_res);
2606
2607	if (likely(!ret)) {
2608		if (!do_swap_account)
2609			return CHARGE_OK;
2610		ret = res_counter_charge(&memcg->memsw, csize, &fail_res);
2611		if (likely(!ret))
2612			return CHARGE_OK;
2613
2614		res_counter_uncharge(&memcg->res, csize);
2615		mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
2616		flags |= MEM_CGROUP_RECLAIM_NOSWAP;
2617	} else
2618		mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
2619	/*
2620	 * Never reclaim on behalf of optional batching, retry with a
2621	 * single page instead.
2622	 */
2623	if (nr_pages > min_pages)
2624		return CHARGE_RETRY;
2625
2626	if (!(gfp_mask & __GFP_WAIT))
2627		return CHARGE_WOULDBLOCK;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2628
2629	if (gfp_mask & __GFP_NORETRY)
2630		return CHARGE_NOMEM;
 
2631
2632	ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags);
2633	if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2634		return CHARGE_RETRY;
2635	/*
2636	 * Even though the limit is exceeded at this point, reclaim
2637	 * may have been able to free some pages.  Retry the charge
2638	 * before killing the task.
2639	 *
2640	 * Only for regular pages, though: huge pages are rather
2641	 * unlikely to succeed so close to the limit, and we fall back
2642	 * to regular pages anyway in case of failure.
2643	 */
2644	if (nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER) && ret)
2645		return CHARGE_RETRY;
2646
2647	/*
2648	 * At task move, charge accounts can be doubly counted. So, it's
2649	 * better to wait until the end of task_move if something is going on.
2650	 */
2651	if (mem_cgroup_wait_acct_move(mem_over_limit))
2652		return CHARGE_RETRY;
2653
2654	if (invoke_oom)
2655		mem_cgroup_oom(mem_over_limit, gfp_mask, get_order(csize));
2656
2657	return CHARGE_NOMEM;
 
 
2658}
2659
2660/**
2661 * mem_cgroup_try_charge - try charging a memcg
2662 * @memcg: memcg to charge
2663 * @nr_pages: number of pages to charge
2664 * @oom: trigger OOM if reclaim fails
2665 *
2666 * Returns 0 if @memcg was charged successfully, -EINTR if the charge
2667 * was bypassed to root_mem_cgroup, and -ENOMEM if the charge failed.
2668 */
2669static int mem_cgroup_try_charge(struct mem_cgroup *memcg,
2670				 gfp_t gfp_mask,
2671				 unsigned int nr_pages,
2672				 bool oom)
2673{
2674	unsigned int batch = max(CHARGE_BATCH, nr_pages);
2675	int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2676	int ret;
2677
2678	if (mem_cgroup_is_root(memcg))
2679		goto done;
2680	/*
2681	 * Unlike in global OOM situations, memcg is not in a physical
2682	 * memory shortage.  Allow dying and OOM-killed tasks to
2683	 * bypass the last charges so that they can exit quickly and
2684	 * free their memory.
2685	 */
2686	if (unlikely(test_thread_flag(TIF_MEMDIE) ||
2687		     fatal_signal_pending(current)))
2688		goto bypass;
2689
2690	if (unlikely(task_in_memcg_oom(current)))
2691		goto nomem;
2692
2693	if (gfp_mask & __GFP_NOFAIL)
2694		oom = false;
2695again:
2696	if (consume_stock(memcg, nr_pages))
2697		goto done;
2698
2699	do {
2700		bool invoke_oom = oom && !nr_oom_retries;
 
 
 
 
2701
2702		/* If killed, bypass charge */
2703		if (fatal_signal_pending(current))
2704			goto bypass;
2705
2706		ret = mem_cgroup_do_charge(memcg, gfp_mask, batch,
2707					   nr_pages, invoke_oom);
2708		switch (ret) {
2709		case CHARGE_OK:
2710			break;
2711		case CHARGE_RETRY: /* not in OOM situation but retry */
2712			batch = nr_pages;
2713			goto again;
2714		case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
2715			goto nomem;
2716		case CHARGE_NOMEM: /* OOM routine works */
2717			if (!oom || invoke_oom)
2718				goto nomem;
2719			nr_oom_retries--;
2720			break;
2721		}
2722	} while (ret != CHARGE_OK);
2723
2724	if (batch > nr_pages)
2725		refill_stock(memcg, batch - nr_pages);
2726done:
2727	return 0;
2728nomem:
2729	if (!(gfp_mask & __GFP_NOFAIL))
2730		return -ENOMEM;
2731bypass:
2732	return -EINTR;
2733}
2734
2735/**
2736 * mem_cgroup_try_charge_mm - try charging a mm
2737 * @mm: mm_struct to charge
2738 * @nr_pages: number of pages to charge
2739 * @oom: trigger OOM if reclaim fails
2740 *
2741 * Returns the charged mem_cgroup associated with the given mm_struct or
2742 * NULL the charge failed.
2743 */
2744static struct mem_cgroup *mem_cgroup_try_charge_mm(struct mm_struct *mm,
2745				 gfp_t gfp_mask,
2746				 unsigned int nr_pages,
2747				 bool oom)
2748
2749{
2750	struct mem_cgroup *memcg;
2751	int ret;
2752
2753	memcg = get_mem_cgroup_from_mm(mm);
2754	ret = mem_cgroup_try_charge(memcg, gfp_mask, nr_pages, oom);
2755	css_put(&memcg->css);
2756	if (ret == -EINTR)
2757		memcg = root_mem_cgroup;
2758	else if (ret)
2759		memcg = NULL;
 
2760
2761	return memcg;
2762}
2763
2764/*
2765 * Somemtimes we have to undo a charge we got by try_charge().
2766 * This function is for that and do uncharge, put css's refcnt.
2767 * gotten by try_charge().
2768 */
2769static void __mem_cgroup_cancel_charge(struct mem_cgroup *memcg,
2770				       unsigned int nr_pages)
 
2771{
2772	if (!mem_cgroup_is_root(memcg)) {
2773		unsigned long bytes = nr_pages * PAGE_SIZE;
2774
2775		res_counter_uncharge(&memcg->res, bytes);
2776		if (do_swap_account)
2777			res_counter_uncharge(&memcg->memsw, bytes);
2778	}
2779}
2780
2781/*
2782 * Cancel chrages in this cgroup....doesn't propagate to parent cgroup.
2783 * This is useful when moving usage to parent cgroup.
2784 */
2785static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg,
2786					unsigned int nr_pages)
2787{
2788	unsigned long bytes = nr_pages * PAGE_SIZE;
2789
2790	if (mem_cgroup_is_root(memcg))
2791		return;
 
 
 
 
 
 
 
 
 
2792
2793	res_counter_uncharge_until(&memcg->res, memcg->res.parent, bytes);
2794	if (do_swap_account)
2795		res_counter_uncharge_until(&memcg->memsw,
2796						memcg->memsw.parent, bytes);
 
 
 
 
 
2797}
2798
2799/*
2800 * A helper function to get mem_cgroup from ID. must be called under
2801 * rcu_read_lock().  The caller is responsible for calling css_tryget if
2802 * the mem_cgroup is used for charging. (dropping refcnt from swap can be
2803 * called against removed memcg.)
2804 */
2805static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2806{
2807	/* ID 0 is unused ID */
2808	if (!id)
2809		return NULL;
2810	return mem_cgroup_from_id(id);
2811}
2812
2813struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2814{
2815	struct mem_cgroup *memcg = NULL;
2816	struct page_cgroup *pc;
2817	unsigned short id;
2818	swp_entry_t ent;
2819
2820	VM_BUG_ON_PAGE(!PageLocked(page), page);
2821
2822	pc = lookup_page_cgroup(page);
2823	lock_page_cgroup(pc);
2824	if (PageCgroupUsed(pc)) {
2825		memcg = pc->mem_cgroup;
2826		if (memcg && !css_tryget(&memcg->css))
2827			memcg = NULL;
2828	} else if (PageSwapCache(page)) {
2829		ent.val = page_private(page);
2830		id = lookup_swap_cgroup_id(ent);
2831		rcu_read_lock();
2832		memcg = mem_cgroup_lookup(id);
2833		if (memcg && !css_tryget(&memcg->css))
2834			memcg = NULL;
2835		rcu_read_unlock();
2836	}
2837	unlock_page_cgroup(pc);
2838	return memcg;
2839}
2840
2841static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg,
2842				       struct page *page,
2843				       unsigned int nr_pages,
2844				       enum charge_type ctype,
2845				       bool lrucare)
2846{
2847	struct page_cgroup *pc = lookup_page_cgroup(page);
2848	struct zone *uninitialized_var(zone);
2849	struct lruvec *lruvec;
2850	bool was_on_lru = false;
2851	bool anon;
2852
2853	lock_page_cgroup(pc);
2854	VM_BUG_ON_PAGE(PageCgroupUsed(pc), page);
2855	/*
2856	 * we don't need page_cgroup_lock about tail pages, becase they are not
2857	 * accessed by any other context at this point.
 
 
 
 
2858	 */
 
 
2859
2860	/*
2861	 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2862	 * may already be on some other mem_cgroup's LRU.  Take care of it.
 
 
 
 
 
2863	 */
2864	if (lrucare) {
2865		zone = page_zone(page);
2866		spin_lock_irq(&zone->lru_lock);
2867		if (PageLRU(page)) {
2868			lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
2869			ClearPageLRU(page);
2870			del_page_from_lru_list(page, lruvec, page_lru(page));
2871			was_on_lru = true;
2872		}
2873	}
2874
2875	pc->mem_cgroup = memcg;
2876	/*
2877	 * We access a page_cgroup asynchronously without lock_page_cgroup().
2878	 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2879	 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2880	 * before USED bit, we need memory barrier here.
2881	 * See mem_cgroup_add_lru_list(), etc.
2882	 */
2883	smp_wmb();
2884	SetPageCgroupUsed(pc);
2885
2886	if (lrucare) {
2887		if (was_on_lru) {
2888			lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
2889			VM_BUG_ON_PAGE(PageLRU(page), page);
2890			SetPageLRU(page);
2891			add_page_to_lru_list(page, lruvec, page_lru(page));
2892		}
2893		spin_unlock_irq(&zone->lru_lock);
2894	}
2895
2896	if (ctype == MEM_CGROUP_CHARGE_TYPE_ANON)
2897		anon = true;
2898	else
2899		anon = false;
2900
2901	mem_cgroup_charge_statistics(memcg, page, anon, nr_pages);
2902	unlock_page_cgroup(pc);
2903
2904	/*
2905	 * "charge_statistics" updated event counter. Then, check it.
2906	 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2907	 * if they exceeds softlimit.
2908	 */
2909	memcg_check_events(memcg, page);
2910}
2911
2912static DEFINE_MUTEX(set_limit_mutex);
2913
2914#ifdef CONFIG_MEMCG_KMEM
2915static DEFINE_MUTEX(activate_kmem_mutex);
2916
2917static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg)
2918{
2919	return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) &&
2920		memcg_kmem_is_active(memcg);
2921}
2922
2923/*
2924 * This is a bit cumbersome, but it is rarely used and avoids a backpointer
2925 * in the memcg_cache_params struct.
2926 */
2927static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p)
2928{
2929	struct kmem_cache *cachep;
2930
2931	VM_BUG_ON(p->is_root_cache);
2932	cachep = p->root_cache;
2933	return cache_from_memcg_idx(cachep, memcg_cache_id(p->memcg));
2934}
2935
2936#ifdef CONFIG_SLABINFO
2937static int mem_cgroup_slabinfo_read(struct seq_file *m, void *v)
2938{
2939	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
2940	struct memcg_cache_params *params;
2941
2942	if (!memcg_can_account_kmem(memcg))
2943		return -EIO;
2944
2945	print_slabinfo_header(m);
2946
2947	mutex_lock(&memcg->slab_caches_mutex);
2948	list_for_each_entry(params, &memcg->memcg_slab_caches, list)
2949		cache_show(memcg_params_to_cache(params), m);
2950	mutex_unlock(&memcg->slab_caches_mutex);
2951
2952	return 0;
2953}
2954#endif
2955
2956static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, u64 size)
2957{
2958	struct res_counter *fail_res;
2959	int ret = 0;
2960
2961	ret = res_counter_charge(&memcg->kmem, size, &fail_res);
2962	if (ret)
2963		return ret;
2964
2965	ret = mem_cgroup_try_charge(memcg, gfp, size >> PAGE_SHIFT,
2966				    oom_gfp_allowed(gfp));
2967	if (ret == -EINTR)  {
2968		/*
2969		 * mem_cgroup_try_charge() chosed to bypass to root due to
2970		 * OOM kill or fatal signal.  Since our only options are to
2971		 * either fail the allocation or charge it to this cgroup, do
2972		 * it as a temporary condition. But we can't fail. From a
2973		 * kmem/slab perspective, the cache has already been selected,
2974		 * by mem_cgroup_kmem_get_cache(), so it is too late to change
2975		 * our minds.
2976		 *
2977		 * This condition will only trigger if the task entered
2978		 * memcg_charge_kmem in a sane state, but was OOM-killed during
2979		 * mem_cgroup_try_charge() above. Tasks that were already
2980		 * dying when the allocation triggers should have been already
2981		 * directed to the root cgroup in memcontrol.h
2982		 */
2983		res_counter_charge_nofail(&memcg->res, size, &fail_res);
2984		if (do_swap_account)
2985			res_counter_charge_nofail(&memcg->memsw, size,
2986						  &fail_res);
2987		ret = 0;
2988	} else if (ret)
2989		res_counter_uncharge(&memcg->kmem, size);
2990
2991	return ret;
2992}
2993
2994static void memcg_uncharge_kmem(struct mem_cgroup *memcg, u64 size)
2995{
2996	res_counter_uncharge(&memcg->res, size);
2997	if (do_swap_account)
2998		res_counter_uncharge(&memcg->memsw, size);
2999
3000	/* Not down to 0 */
3001	if (res_counter_uncharge(&memcg->kmem, size))
3002		return;
3003
3004	/*
3005	 * Releases a reference taken in kmem_cgroup_css_offline in case
3006	 * this last uncharge is racing with the offlining code or it is
3007	 * outliving the memcg existence.
3008	 *
3009	 * The memory barrier imposed by test&clear is paired with the
3010	 * explicit one in memcg_kmem_mark_dead().
3011	 */
3012	if (memcg_kmem_test_and_clear_dead(memcg))
3013		css_put(&memcg->css);
3014}
3015
3016/*
3017 * helper for acessing a memcg's index. It will be used as an index in the
3018 * child cache array in kmem_cache, and also to derive its name. This function
3019 * will return -1 when this is not a kmem-limited memcg.
3020 */
3021int memcg_cache_id(struct mem_cgroup *memcg)
3022{
3023	return memcg ? memcg->kmemcg_id : -1;
3024}
3025
3026static size_t memcg_caches_array_size(int num_groups)
3027{
3028	ssize_t size;
3029	if (num_groups <= 0)
3030		return 0;
3031
3032	size = 2 * num_groups;
3033	if (size < MEMCG_CACHES_MIN_SIZE)
3034		size = MEMCG_CACHES_MIN_SIZE;
3035	else if (size > MEMCG_CACHES_MAX_SIZE)
3036		size = MEMCG_CACHES_MAX_SIZE;
 
 
 
 
3037
3038	return size;
3039}
 
 
 
 
 
 
 
 
 
3040
3041/*
3042 * We should update the current array size iff all caches updates succeed. This
3043 * can only be done from the slab side. The slab mutex needs to be held when
3044 * calling this.
3045 */
3046void memcg_update_array_size(int num)
3047{
3048	if (num > memcg_limited_groups_array_size)
3049		memcg_limited_groups_array_size = memcg_caches_array_size(num);
3050}
3051
3052static void kmem_cache_destroy_work_func(struct work_struct *w);
3053
3054int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
3055{
3056	struct memcg_cache_params *cur_params = s->memcg_params;
3057
3058	VM_BUG_ON(!is_root_cache(s));
3059
3060	if (num_groups > memcg_limited_groups_array_size) {
3061		int i;
3062		struct memcg_cache_params *new_params;
3063		ssize_t size = memcg_caches_array_size(num_groups);
3064
3065		size *= sizeof(void *);
3066		size += offsetof(struct memcg_cache_params, memcg_caches);
3067
3068		new_params = kzalloc(size, GFP_KERNEL);
3069		if (!new_params)
3070			return -ENOMEM;
3071
3072		new_params->is_root_cache = true;
3073
3074		/*
3075		 * There is the chance it will be bigger than
3076		 * memcg_limited_groups_array_size, if we failed an allocation
3077		 * in a cache, in which case all caches updated before it, will
3078		 * have a bigger array.
3079		 *
3080		 * But if that is the case, the data after
3081		 * memcg_limited_groups_array_size is certainly unused
3082		 */
3083		for (i = 0; i < memcg_limited_groups_array_size; i++) {
3084			if (!cur_params->memcg_caches[i])
3085				continue;
3086			new_params->memcg_caches[i] =
3087						cur_params->memcg_caches[i];
3088		}
3089
3090		/*
3091		 * Ideally, we would wait until all caches succeed, and only
3092		 * then free the old one. But this is not worth the extra
3093		 * pointer per-cache we'd have to have for this.
3094		 *
3095		 * It is not a big deal if some caches are left with a size
3096		 * bigger than the others. And all updates will reset this
3097		 * anyway.
3098		 */
3099		rcu_assign_pointer(s->memcg_params, new_params);
3100		if (cur_params)
3101			kfree_rcu(cur_params, rcu_head);
3102	}
3103	return 0;
3104}
3105
3106char *memcg_create_cache_name(struct mem_cgroup *memcg,
3107			      struct kmem_cache *root_cache)
3108{
3109	static char *buf = NULL;
3110
3111	/*
3112	 * We need a mutex here to protect the shared buffer. Since this is
3113	 * expected to be called only on cache creation, we can employ the
3114	 * slab_mutex for that purpose.
 
3115	 */
3116	lockdep_assert_held(&slab_mutex);
3117
3118	if (!buf) {
3119		buf = kmalloc(NAME_MAX + 1, GFP_KERNEL);
3120		if (!buf)
3121			return NULL;
3122	}
3123
3124	cgroup_name(memcg->css.cgroup, buf, NAME_MAX + 1);
3125	return kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name,
3126			 memcg_cache_id(memcg), buf);
3127}
3128
3129int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s,
3130			     struct kmem_cache *root_cache)
3131{
3132	size_t size;
3133
3134	if (!memcg_kmem_enabled())
3135		return 0;
3136
3137	if (!memcg) {
3138		size = offsetof(struct memcg_cache_params, memcg_caches);
3139		size += memcg_limited_groups_array_size * sizeof(void *);
3140	} else
3141		size = sizeof(struct memcg_cache_params);
3142
3143	s->memcg_params = kzalloc(size, GFP_KERNEL);
3144	if (!s->memcg_params)
3145		return -ENOMEM;
3146
3147	if (memcg) {
3148		s->memcg_params->memcg = memcg;
3149		s->memcg_params->root_cache = root_cache;
3150		INIT_WORK(&s->memcg_params->destroy,
3151				kmem_cache_destroy_work_func);
3152		css_get(&memcg->css);
3153	} else
3154		s->memcg_params->is_root_cache = true;
3155
3156	return 0;
3157}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3158
3159void memcg_free_cache_params(struct kmem_cache *s)
3160{
3161	if (!s->memcg_params)
3162		return;
3163	if (!s->memcg_params->is_root_cache)
3164		css_put(&s->memcg_params->memcg->css);
3165	kfree(s->memcg_params);
3166}
3167
3168void memcg_register_cache(struct kmem_cache *s)
3169{
3170	struct kmem_cache *root;
3171	struct mem_cgroup *memcg;
3172	int id;
3173
3174	if (is_root_cache(s))
3175		return;
 
3176
3177	/*
3178	 * Holding the slab_mutex assures nobody will touch the memcg_caches
3179	 * array while we are modifying it.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3180	 */
3181	lockdep_assert_held(&slab_mutex);
3182
3183	root = s->memcg_params->root_cache;
3184	memcg = s->memcg_params->memcg;
3185	id = memcg_cache_id(memcg);
3186
3187	/*
3188	 * Since readers won't lock (see cache_from_memcg_idx()), we need a
3189	 * barrier here to ensure nobody will see the kmem_cache partially
3190	 * initialized.
3191	 */
3192	smp_wmb();
 
3193
3194	/*
3195	 * Initialize the pointer to this cache in its parent's memcg_params
3196	 * before adding it to the memcg_slab_caches list, otherwise we can
3197	 * fail to convert memcg_params_to_cache() while traversing the list.
3198	 */
3199	VM_BUG_ON(root->memcg_params->memcg_caches[id]);
3200	root->memcg_params->memcg_caches[id] = s;
 
3201
3202	mutex_lock(&memcg->slab_caches_mutex);
3203	list_add(&s->memcg_params->list, &memcg->memcg_slab_caches);
3204	mutex_unlock(&memcg->slab_caches_mutex);
3205}
3206
3207void memcg_unregister_cache(struct kmem_cache *s)
3208{
3209	struct kmem_cache *root;
3210	struct mem_cgroup *memcg;
3211	int id;
3212
3213	if (is_root_cache(s))
3214		return;
 
3215
3216	/*
3217	 * Holding the slab_mutex assures nobody will touch the memcg_caches
3218	 * array while we are modifying it.
 
 
 
 
 
3219	 */
3220	lockdep_assert_held(&slab_mutex);
 
3221
3222	root = s->memcg_params->root_cache;
3223	memcg = s->memcg_params->memcg;
3224	id = memcg_cache_id(memcg);
 
 
 
 
 
 
 
 
 
 
3225
3226	mutex_lock(&memcg->slab_caches_mutex);
3227	list_del(&s->memcg_params->list);
3228	mutex_unlock(&memcg->slab_caches_mutex);
 
 
 
 
 
 
 
 
 
 
 
 
3229
3230	/*
3231	 * Clear the pointer to this cache in its parent's memcg_params only
3232	 * after removing it from the memcg_slab_caches list, otherwise we can
3233	 * fail to convert memcg_params_to_cache() while traversing the list.
3234	 */
3235	VM_BUG_ON(root->memcg_params->memcg_caches[id] != s);
3236	root->memcg_params->memcg_caches[id] = NULL;
 
 
 
 
 
3237}
3238
3239/*
3240 * During the creation a new cache, we need to disable our accounting mechanism
3241 * altogether. This is true even if we are not creating, but rather just
3242 * enqueing new caches to be created.
3243 *
3244 * This is because that process will trigger allocations; some visible, like
3245 * explicit kmallocs to auxiliary data structures, name strings and internal
3246 * cache structures; some well concealed, like INIT_WORK() that can allocate
3247 * objects during debug.
3248 *
3249 * If any allocation happens during memcg_kmem_get_cache, we will recurse back
3250 * to it. This may not be a bounded recursion: since the first cache creation
3251 * failed to complete (waiting on the allocation), we'll just try to create the
3252 * cache again, failing at the same point.
3253 *
3254 * memcg_kmem_get_cache is prepared to abort after seeing a positive count of
3255 * memcg_kmem_skip_account. So we enclose anything that might allocate memory
3256 * inside the following two functions.
3257 */
3258static inline void memcg_stop_kmem_account(void)
3259{
3260	VM_BUG_ON(!current->mm);
3261	current->memcg_kmem_skip_account++;
3262}
3263
3264static inline void memcg_resume_kmem_account(void)
3265{
3266	VM_BUG_ON(!current->mm);
3267	current->memcg_kmem_skip_account--;
3268}
3269
3270static void kmem_cache_destroy_work_func(struct work_struct *w)
 
 
 
 
 
3271{
3272	struct kmem_cache *cachep;
3273	struct memcg_cache_params *p;
3274
3275	p = container_of(w, struct memcg_cache_params, destroy);
3276
3277	cachep = memcg_params_to_cache(p);
 
 
 
3278
 
 
 
3279	/*
3280	 * If we get down to 0 after shrink, we could delete right away.
3281	 * However, memcg_release_pages() already puts us back in the workqueue
3282	 * in that case. If we proceed deleting, we'll get a dangling
3283	 * reference, and removing the object from the workqueue in that case
3284	 * is unnecessary complication. We are not a fast path.
3285	 *
3286	 * Note that this case is fundamentally different from racing with
3287	 * shrink_slab(): if memcg_cgroup_destroy_cache() is called in
3288	 * kmem_cache_shrink, not only we would be reinserting a dead cache
3289	 * into the queue, but doing so from inside the worker racing to
3290	 * destroy it.
3291	 *
3292	 * So if we aren't down to zero, we'll just schedule a worker and try
3293	 * again
 
 
 
3294	 */
3295	if (atomic_read(&cachep->memcg_params->nr_pages) != 0)
3296		kmem_cache_shrink(cachep);
3297	else
3298		kmem_cache_destroy(cachep);
3299}
3300
3301void mem_cgroup_destroy_cache(struct kmem_cache *cachep)
 
 
 
 
 
3302{
3303	if (!cachep->memcg_params->dead)
3304		return;
3305
3306	/*
3307	 * There are many ways in which we can get here.
3308	 *
3309	 * We can get to a memory-pressure situation while the delayed work is
3310	 * still pending to run. The vmscan shrinkers can then release all
3311	 * cache memory and get us to destruction. If this is the case, we'll
3312	 * be executed twice, which is a bug (the second time will execute over
3313	 * bogus data). In this case, cancelling the work should be fine.
3314	 *
3315	 * But we can also get here from the worker itself, if
3316	 * kmem_cache_shrink is enough to shake all the remaining objects and
3317	 * get the page count to 0. In this case, we'll deadlock if we try to
3318	 * cancel the work (the worker runs with an internal lock held, which
3319	 * is the same lock we would hold for cancel_work_sync().)
3320	 *
3321	 * Since we can't possibly know who got us here, just refrain from
3322	 * running if there is already work pending
3323	 */
3324	if (work_pending(&cachep->memcg_params->destroy))
3325		return;
3326	/*
3327	 * We have to defer the actual destroying to a workqueue, because
3328	 * we might currently be in a context that cannot sleep.
3329	 */
3330	schedule_work(&cachep->memcg_params->destroy);
3331}
3332
3333int __kmem_cache_destroy_memcg_children(struct kmem_cache *s)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3334{
3335	struct kmem_cache *c;
3336	int i, failed = 0;
3337
3338	/*
3339	 * If the cache is being destroyed, we trust that there is no one else
3340	 * requesting objects from it. Even if there are, the sanity checks in
3341	 * kmem_cache_destroy should caught this ill-case.
3342	 *
3343	 * Still, we don't want anyone else freeing memcg_caches under our
3344	 * noses, which can happen if a new memcg comes to life. As usual,
3345	 * we'll take the activate_kmem_mutex to protect ourselves against
3346	 * this.
3347	 */
3348	mutex_lock(&activate_kmem_mutex);
3349	for_each_memcg_cache_index(i) {
3350		c = cache_from_memcg_idx(s, i);
3351		if (!c)
3352			continue;
 
 
 
 
3353
 
 
3354		/*
3355		 * We will now manually delete the caches, so to avoid races
3356		 * we need to cancel all pending destruction workers and
3357		 * proceed with destruction ourselves.
3358		 *
3359		 * kmem_cache_destroy() will call kmem_cache_shrink internally,
3360		 * and that could spawn the workers again: it is likely that
3361		 * the cache still have active pages until this very moment.
3362		 * This would lead us back to mem_cgroup_destroy_cache.
3363		 *
3364		 * But that will not execute at all if the "dead" flag is not
3365		 * set, so flip it down to guarantee we are in control.
3366		 */
3367		c->memcg_params->dead = false;
3368		cancel_work_sync(&c->memcg_params->destroy);
3369		kmem_cache_destroy(c);
3370
3371		if (cache_from_memcg_idx(s, i))
3372			failed++;
 
 
 
3373	}
3374	mutex_unlock(&activate_kmem_mutex);
3375	return failed;
 
3376}
3377
3378static void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg)
 
3379{
3380	struct kmem_cache *cachep;
3381	struct memcg_cache_params *params;
 
 
 
 
 
 
 
 
 
 
 
 
3382
3383	if (!memcg_kmem_is_active(memcg))
3384		return;
 
3385
3386	mutex_lock(&memcg->slab_caches_mutex);
3387	list_for_each_entry(params, &memcg->memcg_slab_caches, list) {
3388		cachep = memcg_params_to_cache(params);
3389		cachep->memcg_params->dead = true;
3390		schedule_work(&cachep->memcg_params->destroy);
3391	}
3392	mutex_unlock(&memcg->slab_caches_mutex);
3393}
3394
3395struct create_work {
3396	struct mem_cgroup *memcg;
3397	struct kmem_cache *cachep;
3398	struct work_struct work;
3399};
3400
3401static void memcg_create_cache_work_func(struct work_struct *w)
3402{
3403	struct create_work *cw = container_of(w, struct create_work, work);
3404	struct mem_cgroup *memcg = cw->memcg;
3405	struct kmem_cache *cachep = cw->cachep;
3406
3407	kmem_cache_create_memcg(memcg, cachep);
3408	css_put(&memcg->css);
3409	kfree(cw);
 
 
 
 
 
3410}
3411
3412/*
3413 * Enqueue the creation of a per-memcg kmem_cache.
 
 
 
 
 
 
 
 
 
 
 
3414 */
3415static void __memcg_create_cache_enqueue(struct mem_cgroup *memcg,
3416					 struct kmem_cache *cachep)
3417{
3418	struct create_work *cw;
3419
3420	cw = kmalloc(sizeof(struct create_work), GFP_NOWAIT);
3421	if (cw == NULL) {
3422		css_put(&memcg->css);
3423		return;
3424	}
3425
3426	cw->memcg = memcg;
3427	cw->cachep = cachep;
 
 
3428
3429	INIT_WORK(&cw->work, memcg_create_cache_work_func);
3430	schedule_work(&cw->work);
3431}
3432
3433static void memcg_create_cache_enqueue(struct mem_cgroup *memcg,
3434				       struct kmem_cache *cachep)
3435{
3436	/*
3437	 * We need to stop accounting when we kmalloc, because if the
3438	 * corresponding kmalloc cache is not yet created, the first allocation
3439	 * in __memcg_create_cache_enqueue will recurse.
3440	 *
3441	 * However, it is better to enclose the whole function. Depending on
3442	 * the debugging options enabled, INIT_WORK(), for instance, can
3443	 * trigger an allocation. This too, will make us recurse. Because at
3444	 * this point we can't allow ourselves back into memcg_kmem_get_cache,
3445	 * the safest choice is to do it like this, wrapping the whole function.
3446	 */
3447	memcg_stop_kmem_account();
3448	__memcg_create_cache_enqueue(memcg, cachep);
3449	memcg_resume_kmem_account();
3450}
3451/*
3452 * Return the kmem_cache we're supposed to use for a slab allocation.
3453 * We try to use the current memcg's version of the cache.
3454 *
3455 * If the cache does not exist yet, if we are the first user of it,
3456 * we either create it immediately, if possible, or create it asynchronously
3457 * in a workqueue.
3458 * In the latter case, we will let the current allocation go through with
3459 * the original cache.
3460 *
3461 * Can't be called in interrupt context or from kernel threads.
3462 * This function needs to be called with rcu_read_lock() held.
 
 
3463 */
3464struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep,
3465					  gfp_t gfp)
3466{
3467	struct mem_cgroup *memcg;
3468	struct kmem_cache *memcg_cachep;
3469
3470	VM_BUG_ON(!cachep->memcg_params);
3471	VM_BUG_ON(!cachep->memcg_params->is_root_cache);
3472
3473	if (!current->mm || current->memcg_kmem_skip_account)
3474		return cachep;
3475
3476	rcu_read_lock();
3477	memcg = mem_cgroup_from_task(rcu_dereference(current->mm->owner));
3478
3479	if (!memcg_can_account_kmem(memcg))
3480		goto out;
 
3481
3482	memcg_cachep = cache_from_memcg_idx(cachep, memcg_cache_id(memcg));
3483	if (likely(memcg_cachep)) {
3484		cachep = memcg_cachep;
3485		goto out;
 
3486	}
3487
3488	/* The corresponding put will be done in the workqueue. */
3489	if (!css_tryget(&memcg->css))
3490		goto out;
3491	rcu_read_unlock();
3492
3493	/*
3494	 * If we are in a safe context (can wait, and not in interrupt
3495	 * context), we could be be predictable and return right away.
3496	 * This would guarantee that the allocation being performed
3497	 * already belongs in the new cache.
3498	 *
3499	 * However, there are some clashes that can arrive from locking.
3500	 * For instance, because we acquire the slab_mutex while doing
3501	 * kmem_cache_dup, this means no further allocation could happen
3502	 * with the slab_mutex held.
3503	 *
3504	 * Also, because cache creation issue get_online_cpus(), this
3505	 * creates a lock chain: memcg_slab_mutex -> cpu_hotplug_mutex,
3506	 * that ends up reversed during cpu hotplug. (cpuset allocates
3507	 * a bunch of GFP_KERNEL memory during cpuup). Due to all that,
3508	 * better to defer everything.
3509	 */
3510	memcg_create_cache_enqueue(memcg, cachep);
3511	return cachep;
3512out:
3513	rcu_read_unlock();
3514	return cachep;
3515}
3516EXPORT_SYMBOL(__memcg_kmem_get_cache);
3517
3518/*
3519 * We need to verify if the allocation against current->mm->owner's memcg is
3520 * possible for the given order. But the page is not allocated yet, so we'll
3521 * need a further commit step to do the final arrangements.
3522 *
3523 * It is possible for the task to switch cgroups in this mean time, so at
3524 * commit time, we can't rely on task conversion any longer.  We'll then use
3525 * the handle argument to return to the caller which cgroup we should commit
3526 * against. We could also return the memcg directly and avoid the pointer
3527 * passing, but a boolean return value gives better semantics considering
3528 * the compiled-out case as well.
3529 *
3530 * Returning true means the allocation is possible.
3531 */
3532bool
3533__memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order)
3534{
3535	struct mem_cgroup *memcg;
3536	int ret;
3537
3538	*_memcg = NULL;
 
 
 
 
 
 
 
3539
3540	/*
3541	 * Disabling accounting is only relevant for some specific memcg
3542	 * internal allocations. Therefore we would initially not have such
3543	 * check here, since direct calls to the page allocator that are marked
3544	 * with GFP_KMEMCG only happen outside memcg core. We are mostly
3545	 * concerned with cache allocations, and by having this test at
3546	 * memcg_kmem_get_cache, we are already able to relay the allocation to
3547	 * the root cache and bypass the memcg cache altogether.
3548	 *
3549	 * There is one exception, though: the SLUB allocator does not create
3550	 * large order caches, but rather service large kmallocs directly from
3551	 * the page allocator. Therefore, the following sequence when backed by
3552	 * the SLUB allocator:
3553	 *
3554	 *	memcg_stop_kmem_account();
3555	 *	kmalloc(<large_number>)
3556	 *	memcg_resume_kmem_account();
3557	 *
3558	 * would effectively ignore the fact that we should skip accounting,
3559	 * since it will drive us directly to this function without passing
3560	 * through the cache selector memcg_kmem_get_cache. Such large
3561	 * allocations are extremely rare but can happen, for instance, for the
3562	 * cache arrays. We bring this test here.
3563	 */
3564	if (!current->mm || current->memcg_kmem_skip_account)
3565		return true;
3566
3567	memcg = get_mem_cgroup_from_mm(current->mm);
 
 
3568
3569	if (!memcg_can_account_kmem(memcg)) {
3570		css_put(&memcg->css);
3571		return true;
3572	}
 
 
 
 
3573
3574	ret = memcg_charge_kmem(memcg, gfp, PAGE_SIZE << order);
3575	if (!ret)
3576		*_memcg = memcg;
 
 
 
3577
3578	css_put(&memcg->css);
3579	return (ret == 0);
 
 
 
 
 
 
 
 
 
 
 
3580}
3581
3582void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg,
3583			      int order)
3584{
3585	struct page_cgroup *pc;
 
3586
3587	VM_BUG_ON(mem_cgroup_is_root(memcg));
 
 
 
 
 
 
 
 
 
 
 
 
 
3588
3589	/* The page allocation failed. Revert */
3590	if (!page) {
3591		memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
3592		return;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3593	}
3594
3595	pc = lookup_page_cgroup(page);
3596	lock_page_cgroup(pc);
3597	pc->mem_cgroup = memcg;
3598	SetPageCgroupUsed(pc);
3599	unlock_page_cgroup(pc);
3600}
3601
3602void __memcg_kmem_uncharge_pages(struct page *page, int order)
3603{
3604	struct mem_cgroup *memcg = NULL;
3605	struct page_cgroup *pc;
3606
 
 
3607
3608	pc = lookup_page_cgroup(page);
3609	/*
3610	 * Fast unlocked return. Theoretically might have changed, have to
3611	 * check again after locking.
3612	 */
3613	if (!PageCgroupUsed(pc))
3614		return;
3615
3616	lock_page_cgroup(pc);
3617	if (PageCgroupUsed(pc)) {
3618		memcg = pc->mem_cgroup;
3619		ClearPageCgroupUsed(pc);
 
 
 
3620	}
3621	unlock_page_cgroup(pc);
3622
3623	/*
3624	 * We trust that only if there is a memcg associated with the page, it
3625	 * is a valid allocation
3626	 */
3627	if (!memcg)
3628		return;
3629
3630	VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page);
3631	memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
3632}
3633#else
3634static inline void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg)
3635{
 
 
 
 
 
 
 
3636}
3637#endif /* CONFIG_MEMCG_KMEM */
3638
3639#ifdef CONFIG_TRANSPARENT_HUGEPAGE
3640
3641#define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION)
3642/*
3643 * Because tail pages are not marked as "used", set it. We're under
3644 * zone->lru_lock, 'splitting on pmd' and compound_lock.
3645 * charge/uncharge will be never happen and move_account() is done under
3646 * compound_lock(), so we don't have to take care of races.
3647 */
3648void mem_cgroup_split_huge_fixup(struct page *head)
 
3649{
3650	struct page_cgroup *head_pc = lookup_page_cgroup(head);
3651	struct page_cgroup *pc;
3652	struct mem_cgroup *memcg;
3653	int i;
3654
3655	if (mem_cgroup_disabled())
3656		return;
3657
3658	memcg = head_pc->mem_cgroup;
3659	for (i = 1; i < HPAGE_PMD_NR; i++) {
3660		pc = head_pc + i;
3661		pc->mem_cgroup = memcg;
3662		smp_wmb();/* see __commit_charge() */
3663		pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
3664	}
3665	__this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
3666		       HPAGE_PMD_NR);
3667}
3668#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3669
3670/**
3671 * mem_cgroup_move_account - move account of the page
3672 * @page: the page
3673 * @nr_pages: number of regular pages (>1 for huge pages)
3674 * @pc:	page_cgroup of the page.
3675 * @from: mem_cgroup which the page is moved from.
3676 * @to:	mem_cgroup which the page is moved to. @from != @to.
3677 *
3678 * The caller must confirm following.
3679 * - page is not on LRU (isolate_page() is useful.)
3680 * - compound_lock is held when nr_pages > 1
3681 *
3682 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
3683 * from old cgroup.
3684 */
3685static int mem_cgroup_move_account(struct page *page,
3686				   unsigned int nr_pages,
3687				   struct page_cgroup *pc,
3688				   struct mem_cgroup *from,
3689				   struct mem_cgroup *to)
3690{
3691	unsigned long flags;
3692	int ret;
3693	bool anon = PageAnon(page);
3694
3695	VM_BUG_ON(from == to);
3696	VM_BUG_ON_PAGE(PageLRU(page), page);
3697	/*
3698	 * The page is isolated from LRU. So, collapse function
3699	 * will not handle this page. But page splitting can happen.
3700	 * Do this check under compound_page_lock(). The caller should
3701	 * hold it.
3702	 */
3703	ret = -EBUSY;
3704	if (nr_pages > 1 && !PageTransHuge(page))
3705		goto out;
3706
3707	lock_page_cgroup(pc);
3708
3709	ret = -EINVAL;
3710	if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
3711		goto unlock;
3712
3713	move_lock_mem_cgroup(from, &flags);
3714
3715	if (!anon && page_mapped(page)) {
3716		__this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
3717			       nr_pages);
3718		__this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
3719			       nr_pages);
3720	}
3721
3722	if (PageWriteback(page)) {
3723		__this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK],
3724			       nr_pages);
3725		__this_cpu_add(to->stat->count[MEM_CGROUP_STAT_WRITEBACK],
3726			       nr_pages);
3727	}
3728
3729	mem_cgroup_charge_statistics(from, page, anon, -nr_pages);
3730
3731	/* caller should have done css_get */
3732	pc->mem_cgroup = to;
3733	mem_cgroup_charge_statistics(to, page, anon, nr_pages);
3734	move_unlock_mem_cgroup(from, &flags);
3735	ret = 0;
3736unlock:
3737	unlock_page_cgroup(pc);
3738	/*
3739	 * check events
3740	 */
3741	memcg_check_events(to, page);
3742	memcg_check_events(from, page);
3743out:
 
 
3744	return ret;
3745}
3746
3747/**
3748 * mem_cgroup_move_parent - moves page to the parent group
3749 * @page: the page to move
3750 * @pc: page_cgroup of the page
3751 * @child: page's cgroup
3752 *
3753 * move charges to its parent or the root cgroup if the group has no
3754 * parent (aka use_hierarchy==0).
3755 * Although this might fail (get_page_unless_zero, isolate_lru_page or
3756 * mem_cgroup_move_account fails) the failure is always temporary and
3757 * it signals a race with a page removal/uncharge or migration. In the
3758 * first case the page is on the way out and it will vanish from the LRU
3759 * on the next attempt and the call should be retried later.
3760 * Isolation from the LRU fails only if page has been isolated from
3761 * the LRU since we looked at it and that usually means either global
3762 * reclaim or migration going on. The page will either get back to the
3763 * LRU or vanish.
3764 * Finaly mem_cgroup_move_account fails only if the page got uncharged
3765 * (!PageCgroupUsed) or moved to a different group. The page will
3766 * disappear in the next attempt.
3767 */
3768static int mem_cgroup_move_parent(struct page *page,
3769				  struct page_cgroup *pc,
3770				  struct mem_cgroup *child)
3771{
3772	struct mem_cgroup *parent;
3773	unsigned int nr_pages;
3774	unsigned long uninitialized_var(flags);
3775	int ret;
3776
3777	VM_BUG_ON(mem_cgroup_is_root(child));
3778
3779	ret = -EBUSY;
3780	if (!get_page_unless_zero(page))
3781		goto out;
3782	if (isolate_lru_page(page))
3783		goto put;
3784
3785	nr_pages = hpage_nr_pages(page);
3786
3787	parent = parent_mem_cgroup(child);
3788	/*
3789	 * If no parent, move charges to root cgroup.
3790	 */
3791	if (!parent)
3792		parent = root_mem_cgroup;
3793
3794	if (nr_pages > 1) {
3795		VM_BUG_ON_PAGE(!PageTransHuge(page), page);
3796		flags = compound_lock_irqsave(page);
 
 
 
 
 
 
3797	}
3798
3799	ret = mem_cgroup_move_account(page, nr_pages,
3800				pc, child, parent);
3801	if (!ret)
3802		__mem_cgroup_cancel_local_charge(child, nr_pages);
3803
3804	if (nr_pages > 1)
3805		compound_unlock_irqrestore(page, flags);
3806	putback_lru_page(page);
3807put:
3808	put_page(page);
3809out:
3810	return ret;
3811}
3812
3813int mem_cgroup_charge_anon(struct page *page,
3814			      struct mm_struct *mm, gfp_t gfp_mask)
 
 
 
 
3815{
3816	unsigned int nr_pages = 1;
3817	struct mem_cgroup *memcg;
3818	bool oom = true;
3819
3820	if (mem_cgroup_disabled())
3821		return 0;
3822
3823	VM_BUG_ON_PAGE(page_mapped(page), page);
3824	VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page);
3825	VM_BUG_ON(!mm);
3826
3827	if (PageTransHuge(page)) {
3828		nr_pages <<= compound_order(page);
3829		VM_BUG_ON_PAGE(!PageTransHuge(page), page);
3830		/*
3831		 * Never OOM-kill a process for a huge page.  The
3832		 * fault handler will fall back to regular pages.
3833		 */
3834		oom = false;
3835	}
3836
3837	memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, nr_pages, oom);
3838	if (!memcg)
3839		return -ENOMEM;
3840	__mem_cgroup_commit_charge(memcg, page, nr_pages,
3841				   MEM_CGROUP_CHARGE_TYPE_ANON, false);
3842	return 0;
3843}
3844
3845/*
3846 * While swap-in, try_charge -> commit or cancel, the page is locked.
3847 * And when try_charge() successfully returns, one refcnt to memcg without
3848 * struct page_cgroup is acquired. This refcnt will be consumed by
3849 * "commit()" or removed by "cancel()"
3850 */
3851static int __mem_cgroup_try_charge_swapin(struct mm_struct *mm,
3852					  struct page *page,
3853					  gfp_t mask,
3854					  struct mem_cgroup **memcgp)
3855{
3856	struct mem_cgroup *memcg = NULL;
3857	struct page_cgroup *pc;
3858	int ret;
 
3859
3860	pc = lookup_page_cgroup(page);
3861	/*
3862	 * Every swap fault against a single page tries to charge the
3863	 * page, bail as early as possible.  shmem_unuse() encounters
3864	 * already charged pages, too.  The USED bit is protected by
3865	 * the page lock, which serializes swap cache removal, which
3866	 * in turn serializes uncharging.
3867	 */
3868	if (PageCgroupUsed(pc))
3869		goto out;
3870	if (do_swap_account)
3871		memcg = try_get_mem_cgroup_from_page(page);
3872	if (!memcg)
3873		memcg = get_mem_cgroup_from_mm(mm);
3874	ret = mem_cgroup_try_charge(memcg, mask, 1, true);
3875	css_put(&memcg->css);
3876	if (ret == -EINTR)
3877		memcg = root_mem_cgroup;
3878	else if (ret)
3879		return ret;
3880out:
3881	*memcgp = memcg;
3882	return 0;
3883}
3884
3885int mem_cgroup_try_charge_swapin(struct mm_struct *mm, struct page *page,
3886				 gfp_t gfp_mask, struct mem_cgroup **memcgp)
3887{
3888	if (mem_cgroup_disabled()) {
3889		*memcgp = NULL;
3890		return 0;
3891	}
3892	/*
3893	 * A racing thread's fault, or swapoff, may have already
3894	 * updated the pte, and even removed page from swap cache: in
3895	 * those cases unuse_pte()'s pte_same() test will fail; but
3896	 * there's also a KSM case which does need to charge the page.
3897	 */
3898	if (!PageSwapCache(page)) {
3899		struct mem_cgroup *memcg;
 
 
 
 
 
 
 
 
3900
3901		memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, 1, true);
3902		if (!memcg)
3903			return -ENOMEM;
3904		*memcgp = memcg;
3905		return 0;
 
 
 
 
 
 
3906	}
3907	return __mem_cgroup_try_charge_swapin(mm, page, gfp_mask, memcgp);
3908}
3909
3910void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg)
3911{
3912	if (mem_cgroup_disabled())
3913		return;
3914	if (!memcg)
3915		return;
3916	__mem_cgroup_cancel_charge(memcg, 1);
3917}
3918
3919static void
3920__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg,
3921					enum charge_type ctype)
3922{
3923	if (mem_cgroup_disabled())
3924		return;
3925	if (!memcg)
3926		return;
3927
3928	__mem_cgroup_commit_charge(memcg, page, 1, ctype, true);
3929	/*
3930	 * Now swap is on-memory. This means this page may be
3931	 * counted both as mem and swap....double count.
3932	 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
3933	 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
3934	 * may call delete_from_swap_cache() before reach here.
3935	 */
3936	if (do_swap_account && PageSwapCache(page)) {
3937		swp_entry_t ent = {.val = page_private(page)};
3938		mem_cgroup_uncharge_swap(ent);
 
 
 
 
 
 
 
 
3939	}
3940}
 
3941
3942void mem_cgroup_commit_charge_swapin(struct page *page,
3943				     struct mem_cgroup *memcg)
3944{
3945	__mem_cgroup_commit_charge_swapin(page, memcg,
3946					  MEM_CGROUP_CHARGE_TYPE_ANON);
3947}
3948
3949int mem_cgroup_charge_file(struct page *page, struct mm_struct *mm,
3950				gfp_t gfp_mask)
3951{
3952	enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
3953	struct mem_cgroup *memcg;
3954	int ret;
3955
3956	if (mem_cgroup_disabled())
3957		return 0;
3958	if (PageCompound(page))
3959		return 0;
3960
3961	if (PageSwapCache(page)) { /* shmem */
3962		ret = __mem_cgroup_try_charge_swapin(mm, page,
3963						     gfp_mask, &memcg);
3964		if (ret)
3965			return ret;
3966		__mem_cgroup_commit_charge_swapin(page, memcg, type);
3967		return 0;
3968	}
3969
3970	memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, 1, true);
3971	if (!memcg)
3972		return -ENOMEM;
3973	__mem_cgroup_commit_charge(memcg, page, 1, type, false);
3974	return 0;
3975}
3976
3977static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg,
3978				   unsigned int nr_pages,
3979				   const enum charge_type ctype)
3980{
3981	struct memcg_batch_info *batch = NULL;
3982	bool uncharge_memsw = true;
3983
3984	/* If swapout, usage of swap doesn't decrease */
3985	if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
3986		uncharge_memsw = false;
3987
3988	batch = &current->memcg_batch;
3989	/*
3990	 * In usual, we do css_get() when we remember memcg pointer.
3991	 * But in this case, we keep res->usage until end of a series of
3992	 * uncharges. Then, it's ok to ignore memcg's refcnt.
3993	 */
3994	if (!batch->memcg)
3995		batch->memcg = memcg;
3996	/*
3997	 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
3998	 * In those cases, all pages freed continuously can be expected to be in
3999	 * the same cgroup and we have chance to coalesce uncharges.
4000	 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
4001	 * because we want to do uncharge as soon as possible.
4002	 */
4003
4004	if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
4005		goto direct_uncharge;
4006
4007	if (nr_pages > 1)
4008		goto direct_uncharge;
4009
4010	/*
4011	 * In typical case, batch->memcg == mem. This means we can
4012	 * merge a series of uncharges to an uncharge of res_counter.
4013	 * If not, we uncharge res_counter ony by one.
4014	 */
4015	if (batch->memcg != memcg)
4016		goto direct_uncharge;
4017	/* remember freed charge and uncharge it later */
4018	batch->nr_pages++;
4019	if (uncharge_memsw)
4020		batch->memsw_nr_pages++;
4021	return;
4022direct_uncharge:
4023	res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE);
4024	if (uncharge_memsw)
4025		res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE);
4026	if (unlikely(batch->memcg != memcg))
4027		memcg_oom_recover(memcg);
4028}
4029
4030/*
4031 * uncharge if !page_mapped(page)
4032 */
4033static struct mem_cgroup *
4034__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype,
4035			     bool end_migration)
4036{
4037	struct mem_cgroup *memcg = NULL;
4038	unsigned int nr_pages = 1;
4039	struct page_cgroup *pc;
4040	bool anon;
4041
4042	if (mem_cgroup_disabled())
4043		return NULL;
4044
4045	if (PageTransHuge(page)) {
4046		nr_pages <<= compound_order(page);
4047		VM_BUG_ON_PAGE(!PageTransHuge(page), page);
4048	}
4049	/*
4050	 * Check if our page_cgroup is valid
4051	 */
4052	pc = lookup_page_cgroup(page);
4053	if (unlikely(!PageCgroupUsed(pc)))
4054		return NULL;
4055
4056	lock_page_cgroup(pc);
 
4057
4058	memcg = pc->mem_cgroup;
4059
4060	if (!PageCgroupUsed(pc))
4061		goto unlock_out;
4062
4063	anon = PageAnon(page);
 
4064
4065	switch (ctype) {
4066	case MEM_CGROUP_CHARGE_TYPE_ANON:
4067		/*
4068		 * Generally PageAnon tells if it's the anon statistics to be
4069		 * updated; but sometimes e.g. mem_cgroup_uncharge_page() is
4070		 * used before page reached the stage of being marked PageAnon.
4071		 */
4072		anon = true;
4073		/* fallthrough */
4074	case MEM_CGROUP_CHARGE_TYPE_DROP:
4075		/* See mem_cgroup_prepare_migration() */
4076		if (page_mapped(page))
4077			goto unlock_out;
4078		/*
4079		 * Pages under migration may not be uncharged.  But
4080		 * end_migration() /must/ be the one uncharging the
4081		 * unused post-migration page and so it has to call
4082		 * here with the migration bit still set.  See the
4083		 * res_counter handling below.
 
 
 
4084		 */
4085		if (!end_migration && PageCgroupMigration(pc))
4086			goto unlock_out;
4087		break;
4088	case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
4089		if (!PageAnon(page)) {	/* Shared memory */
4090			if (page->mapping && !page_is_file_cache(page))
4091				goto unlock_out;
4092		} else if (page_mapped(page)) /* Anon */
4093				goto unlock_out;
4094		break;
4095	default:
4096		break;
4097	}
4098
4099	mem_cgroup_charge_statistics(memcg, page, anon, -nr_pages);
4100
4101	ClearPageCgroupUsed(pc);
4102	/*
4103	 * pc->mem_cgroup is not cleared here. It will be accessed when it's
4104	 * freed from LRU. This is safe because uncharged page is expected not
4105	 * to be reused (freed soon). Exception is SwapCache, it's handled by
4106	 * special functions.
4107	 */
4108
4109	unlock_page_cgroup(pc);
4110	/*
4111	 * even after unlock, we have memcg->res.usage here and this memcg
4112	 * will never be freed, so it's safe to call css_get().
4113	 */
4114	memcg_check_events(memcg, page);
4115	if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
4116		mem_cgroup_swap_statistics(memcg, true);
4117		css_get(&memcg->css);
 
 
 
 
4118	}
4119	/*
4120	 * Migration does not charge the res_counter for the
4121	 * replacement page, so leave it alone when phasing out the
4122	 * page that is unused after the migration.
4123	 */
4124	if (!end_migration && !mem_cgroup_is_root(memcg))
4125		mem_cgroup_do_uncharge(memcg, nr_pages, ctype);
4126
4127	return memcg;
4128
4129unlock_out:
4130	unlock_page_cgroup(pc);
4131	return NULL;
4132}
4133
4134void mem_cgroup_uncharge_page(struct page *page)
4135{
4136	/* early check. */
4137	if (page_mapped(page))
4138		return;
4139	VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page);
4140	/*
4141	 * If the page is in swap cache, uncharge should be deferred
4142	 * to the swap path, which also properly accounts swap usage
4143	 * and handles memcg lifetime.
4144	 *
4145	 * Note that this check is not stable and reclaim may add the
4146	 * page to swap cache at any time after this.  However, if the
4147	 * page is not in swap cache by the time page->mapcount hits
4148	 * 0, there won't be any page table references to the swap
4149	 * slot, and reclaim will free it and not actually write the
4150	 * page to disk.
4151	 */
4152	if (PageSwapCache(page))
4153		return;
4154	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_ANON, false);
4155}
4156
4157void mem_cgroup_uncharge_cache_page(struct page *page)
 
4158{
4159	VM_BUG_ON_PAGE(page_mapped(page), page);
4160	VM_BUG_ON_PAGE(page->mapping, page);
4161	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false);
4162}
4163
4164/*
4165 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
4166 * In that cases, pages are freed continuously and we can expect pages
4167 * are in the same memcg. All these calls itself limits the number of
4168 * pages freed at once, then uncharge_start/end() is called properly.
4169 * This may be called prural(2) times in a context,
4170 */
4171
4172void mem_cgroup_uncharge_start(void)
4173{
4174	current->memcg_batch.do_batch++;
4175	/* We can do nest. */
4176	if (current->memcg_batch.do_batch == 1) {
4177		current->memcg_batch.memcg = NULL;
4178		current->memcg_batch.nr_pages = 0;
4179		current->memcg_batch.memsw_nr_pages = 0;
4180	}
 
 
4181}
4182
4183void mem_cgroup_uncharge_end(void)
 
4184{
4185	struct memcg_batch_info *batch = &current->memcg_batch;
 
 
 
4186
4187	if (!batch->do_batch)
4188		return;
4189
4190	batch->do_batch--;
4191	if (batch->do_batch) /* If stacked, do nothing. */
4192		return;
 
 
 
 
 
 
 
4193
4194	if (!batch->memcg)
4195		return;
4196	/*
4197	 * This "batch->memcg" is valid without any css_get/put etc...
4198	 * bacause we hide charges behind us.
4199	 */
4200	if (batch->nr_pages)
4201		res_counter_uncharge(&batch->memcg->res,
4202				     batch->nr_pages * PAGE_SIZE);
4203	if (batch->memsw_nr_pages)
4204		res_counter_uncharge(&batch->memcg->memsw,
4205				     batch->memsw_nr_pages * PAGE_SIZE);
4206	memcg_oom_recover(batch->memcg);
4207	/* forget this pointer (for sanity check) */
4208	batch->memcg = NULL;
4209}
4210
4211#ifdef CONFIG_SWAP
4212/*
4213 * called after __delete_from_swap_cache() and drop "page" account.
4214 * memcg information is recorded to swap_cgroup of "ent"
4215 */
4216void
4217mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
4218{
4219	struct mem_cgroup *memcg;
4220	int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
4221
4222	if (!swapout) /* this was a swap cache but the swap is unused ! */
4223		ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
4224
4225	memcg = __mem_cgroup_uncharge_common(page, ctype, false);
 
4226
4227	/*
4228	 * record memcg information,  if swapout && memcg != NULL,
4229	 * css_get() was called in uncharge().
4230	 */
4231	if (do_swap_account && swapout && memcg)
4232		swap_cgroup_record(ent, mem_cgroup_id(memcg));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4233}
4234#endif
4235
4236#ifdef CONFIG_MEMCG_SWAP
 
4237/*
4238 * called from swap_entry_free(). remove record in swap_cgroup and
4239 * uncharge "memsw" account.
4240 */
4241void mem_cgroup_uncharge_swap(swp_entry_t ent)
4242{
4243	struct mem_cgroup *memcg;
4244	unsigned short id;
 
 
 
4245
4246	if (!do_swap_account)
4247		return;
4248
4249	id = swap_cgroup_record(ent, 0);
4250	rcu_read_lock();
4251	memcg = mem_cgroup_lookup(id);
4252	if (memcg) {
4253		/*
4254		 * We uncharge this because swap is freed.
4255		 * This memcg can be obsolete one. We avoid calling css_tryget
4256		 */
4257		if (!mem_cgroup_is_root(memcg))
4258			res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
4259		mem_cgroup_swap_statistics(memcg, false);
4260		css_put(&memcg->css);
4261	}
4262	rcu_read_unlock();
4263}
4264
 
4265/**
4266 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
4267 * @entry: swap entry to be moved
4268 * @from:  mem_cgroup which the entry is moved from
4269 * @to:  mem_cgroup which the entry is moved to
4270 *
4271 * It succeeds only when the swap_cgroup's record for this entry is the same
4272 * as the mem_cgroup's id of @from.
4273 *
4274 * Returns 0 on success, -EINVAL on failure.
4275 *
4276 * The caller must have charged to @to, IOW, called res_counter_charge() about
4277 * both res and memsw, and called css_get().
4278 */
4279static int mem_cgroup_move_swap_account(swp_entry_t entry,
4280				struct mem_cgroup *from, struct mem_cgroup *to)
4281{
4282	unsigned short old_id, new_id;
4283
4284	old_id = mem_cgroup_id(from);
4285	new_id = mem_cgroup_id(to);
4286
4287	if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
4288		mem_cgroup_swap_statistics(from, false);
4289		mem_cgroup_swap_statistics(to, true);
4290		/*
4291		 * This function is only called from task migration context now.
4292		 * It postpones res_counter and refcount handling till the end
4293		 * of task migration(mem_cgroup_clear_mc()) for performance
4294		 * improvement. But we cannot postpone css_get(to)  because if
4295		 * the process that has been moved to @to does swap-in, the
4296		 * refcount of @to might be decreased to 0.
4297		 *
4298		 * We are in attach() phase, so the cgroup is guaranteed to be
4299		 * alive, so we can just call css_get().
4300		 */
4301		css_get(&to->css);
4302		return 0;
4303	}
4304	return -EINVAL;
4305}
4306#else
4307static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
4308				struct mem_cgroup *from, struct mem_cgroup *to)
4309{
4310	return -EINVAL;
4311}
4312#endif
4313
4314/*
4315 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
4316 * page belongs to.
4317 */
4318void mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
4319				  struct mem_cgroup **memcgp)
4320{
4321	struct mem_cgroup *memcg = NULL;
4322	unsigned int nr_pages = 1;
4323	struct page_cgroup *pc;
4324	enum charge_type ctype;
4325
4326	*memcgp = NULL;
4327
4328	if (mem_cgroup_disabled())
4329		return;
4330
4331	if (PageTransHuge(page))
4332		nr_pages <<= compound_order(page);
4333
4334	pc = lookup_page_cgroup(page);
4335	lock_page_cgroup(pc);
4336	if (PageCgroupUsed(pc)) {
4337		memcg = pc->mem_cgroup;
4338		css_get(&memcg->css);
4339		/*
4340		 * At migrating an anonymous page, its mapcount goes down
4341		 * to 0 and uncharge() will be called. But, even if it's fully
4342		 * unmapped, migration may fail and this page has to be
4343		 * charged again. We set MIGRATION flag here and delay uncharge
4344		 * until end_migration() is called
4345		 *
4346		 * Corner Case Thinking
4347		 * A)
4348		 * When the old page was mapped as Anon and it's unmap-and-freed
4349		 * while migration was ongoing.
4350		 * If unmap finds the old page, uncharge() of it will be delayed
4351		 * until end_migration(). If unmap finds a new page, it's
4352		 * uncharged when it make mapcount to be 1->0. If unmap code
4353		 * finds swap_migration_entry, the new page will not be mapped
4354		 * and end_migration() will find it(mapcount==0).
4355		 *
4356		 * B)
4357		 * When the old page was mapped but migraion fails, the kernel
4358		 * remaps it. A charge for it is kept by MIGRATION flag even
4359		 * if mapcount goes down to 0. We can do remap successfully
4360		 * without charging it again.
4361		 *
4362		 * C)
4363		 * The "old" page is under lock_page() until the end of
4364		 * migration, so, the old page itself will not be swapped-out.
4365		 * If the new page is swapped out before end_migraton, our
4366		 * hook to usual swap-out path will catch the event.
4367		 */
4368		if (PageAnon(page))
4369			SetPageCgroupMigration(pc);
4370	}
4371	unlock_page_cgroup(pc);
4372	/*
4373	 * If the page is not charged at this point,
4374	 * we return here.
4375	 */
4376	if (!memcg)
4377		return;
4378
4379	*memcgp = memcg;
4380	/*
4381	 * We charge new page before it's used/mapped. So, even if unlock_page()
4382	 * is called before end_migration, we can catch all events on this new
4383	 * page. In the case new page is migrated but not remapped, new page's
4384	 * mapcount will be finally 0 and we call uncharge in end_migration().
4385	 */
4386	if (PageAnon(page))
4387		ctype = MEM_CGROUP_CHARGE_TYPE_ANON;
4388	else
4389		ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
4390	/*
4391	 * The page is committed to the memcg, but it's not actually
4392	 * charged to the res_counter since we plan on replacing the
4393	 * old one and only one page is going to be left afterwards.
4394	 */
4395	__mem_cgroup_commit_charge(memcg, newpage, nr_pages, ctype, false);
4396}
4397
4398/* remove redundant charge if migration failed*/
4399void mem_cgroup_end_migration(struct mem_cgroup *memcg,
4400	struct page *oldpage, struct page *newpage, bool migration_ok)
4401{
4402	struct page *used, *unused;
4403	struct page_cgroup *pc;
4404	bool anon;
4405
4406	if (!memcg)
4407		return;
4408
4409	if (!migration_ok) {
4410		used = oldpage;
4411		unused = newpage;
4412	} else {
4413		used = newpage;
4414		unused = oldpage;
4415	}
4416	anon = PageAnon(used);
4417	__mem_cgroup_uncharge_common(unused,
4418				     anon ? MEM_CGROUP_CHARGE_TYPE_ANON
4419				     : MEM_CGROUP_CHARGE_TYPE_CACHE,
4420				     true);
4421	css_put(&memcg->css);
4422	/*
4423	 * We disallowed uncharge of pages under migration because mapcount
4424	 * of the page goes down to zero, temporarly.
4425	 * Clear the flag and check the page should be charged.
4426	 */
4427	pc = lookup_page_cgroup(oldpage);
4428	lock_page_cgroup(pc);
4429	ClearPageCgroupMigration(pc);
4430	unlock_page_cgroup(pc);
4431
4432	/*
4433	 * If a page is a file cache, radix-tree replacement is very atomic
4434	 * and we can skip this check. When it was an Anon page, its mapcount
4435	 * goes down to 0. But because we added MIGRATION flage, it's not
4436	 * uncharged yet. There are several case but page->mapcount check
4437	 * and USED bit check in mem_cgroup_uncharge_page() will do enough
4438	 * check. (see prepare_charge() also)
4439	 */
4440	if (anon)
4441		mem_cgroup_uncharge_page(used);
4442}
4443
4444/*
4445 * At replace page cache, newpage is not under any memcg but it's on
4446 * LRU. So, this function doesn't touch res_counter but handles LRU
4447 * in correct way. Both pages are locked so we cannot race with uncharge.
4448 */
4449void mem_cgroup_replace_page_cache(struct page *oldpage,
4450				  struct page *newpage)
4451{
4452	struct mem_cgroup *memcg = NULL;
4453	struct page_cgroup *pc;
4454	enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
4455
4456	if (mem_cgroup_disabled())
4457		return;
4458
4459	pc = lookup_page_cgroup(oldpage);
4460	/* fix accounting on old pages */
4461	lock_page_cgroup(pc);
4462	if (PageCgroupUsed(pc)) {
4463		memcg = pc->mem_cgroup;
4464		mem_cgroup_charge_statistics(memcg, oldpage, false, -1);
4465		ClearPageCgroupUsed(pc);
4466	}
4467	unlock_page_cgroup(pc);
4468
4469	/*
4470	 * When called from shmem_replace_page(), in some cases the
4471	 * oldpage has already been charged, and in some cases not.
4472	 */
4473	if (!memcg)
4474		return;
4475	/*
4476	 * Even if newpage->mapping was NULL before starting replacement,
4477	 * the newpage may be on LRU(or pagevec for LRU) already. We lock
4478	 * LRU while we overwrite pc->mem_cgroup.
4479	 */
4480	__mem_cgroup_commit_charge(memcg, newpage, 1, type, true);
4481}
4482
4483#ifdef CONFIG_DEBUG_VM
4484static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
4485{
4486	struct page_cgroup *pc;
4487
4488	pc = lookup_page_cgroup(page);
4489	/*
4490	 * Can be NULL while feeding pages into the page allocator for
4491	 * the first time, i.e. during boot or memory hotplug;
4492	 * or when mem_cgroup_disabled().
4493	 */
4494	if (likely(pc) && PageCgroupUsed(pc))
4495		return pc;
4496	return NULL;
4497}
4498
4499bool mem_cgroup_bad_page_check(struct page *page)
4500{
4501	if (mem_cgroup_disabled())
4502		return false;
4503
4504	return lookup_page_cgroup_used(page) != NULL;
4505}
4506
4507void mem_cgroup_print_bad_page(struct page *page)
 
4508{
4509	struct page_cgroup *pc;
4510
4511	pc = lookup_page_cgroup_used(page);
4512	if (pc) {
4513		pr_alert("pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
4514			 pc, pc->flags, pc->mem_cgroup);
4515	}
4516}
4517#endif
4518
4519static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
4520				unsigned long long val)
4521{
4522	int retry_count;
4523	u64 memswlimit, memlimit;
4524	int ret = 0;
4525	int children = mem_cgroup_count_children(memcg);
4526	u64 curusage, oldusage;
4527	int enlarge;
4528
4529	/*
4530	 * For keeping hierarchical_reclaim simple, how long we should retry
4531	 * is depends on callers. We set our retry-count to be function
4532	 * of # of children which we should visit in this loop.
4533	 */
4534	retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
4535
4536	oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
4537
4538	enlarge = 0;
4539	while (retry_count) {
4540		if (signal_pending(current)) {
4541			ret = -EINTR;
4542			break;
4543		}
 
 
4544		/*
4545		 * Rather than hide all in some function, I do this in
4546		 * open coded manner. You see what this really does.
4547		 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4548		 */
4549		mutex_lock(&set_limit_mutex);
4550		memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4551		if (memswlimit < val) {
 
4552			ret = -EINVAL;
4553			mutex_unlock(&set_limit_mutex);
4554			break;
4555		}
4556
4557		memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
4558		if (memlimit < val)
4559			enlarge = 1;
4560
4561		ret = res_counter_set_limit(&memcg->res, val);
4562		if (!ret) {
4563			if (memswlimit == val)
4564				memcg->memsw_is_minimum = true;
4565			else
4566				memcg->memsw_is_minimum = false;
4567		}
4568		mutex_unlock(&set_limit_mutex);
4569
4570		if (!ret)
4571			break;
4572
4573		mem_cgroup_reclaim(memcg, GFP_KERNEL,
4574				   MEM_CGROUP_RECLAIM_SHRINK);
4575		curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
4576		/* Usage is reduced ? */
4577		if (curusage >= oldusage)
4578			retry_count--;
4579		else
4580			oldusage = curusage;
4581	}
4582	if (!ret && enlarge)
4583		memcg_oom_recover(memcg);
4584
4585	return ret;
4586}
4587
4588static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
4589					unsigned long long val)
4590{
4591	int retry_count;
4592	u64 memlimit, memswlimit, oldusage, curusage;
4593	int children = mem_cgroup_count_children(memcg);
4594	int ret = -EBUSY;
4595	int enlarge = 0;
4596
4597	/* see mem_cgroup_resize_res_limit */
4598	retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
4599	oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
4600	while (retry_count) {
4601		if (signal_pending(current)) {
4602			ret = -EINTR;
4603			break;
4604		}
4605		/*
4606		 * Rather than hide all in some function, I do this in
4607		 * open coded manner. You see what this really does.
4608		 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4609		 */
4610		mutex_lock(&set_limit_mutex);
4611		memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
4612		if (memlimit > val) {
4613			ret = -EINVAL;
4614			mutex_unlock(&set_limit_mutex);
4615			break;
4616		}
4617		memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4618		if (memswlimit < val)
4619			enlarge = 1;
4620		ret = res_counter_set_limit(&memcg->memsw, val);
4621		if (!ret) {
4622			if (memlimit == val)
4623				memcg->memsw_is_minimum = true;
4624			else
4625				memcg->memsw_is_minimum = false;
4626		}
4627		mutex_unlock(&set_limit_mutex);
4628
4629		if (!ret)
 
 
4630			break;
 
 
4631
4632		mem_cgroup_reclaim(memcg, GFP_KERNEL,
4633				   MEM_CGROUP_RECLAIM_NOSWAP |
4634				   MEM_CGROUP_RECLAIM_SHRINK);
4635		curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
4636		/* Usage is reduced ? */
4637		if (curusage >= oldusage)
4638			retry_count--;
4639		else
4640			oldusage = curusage;
4641	}
4642	if (!ret && enlarge)
4643		memcg_oom_recover(memcg);
 
4644	return ret;
4645}
4646
4647unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
4648					    gfp_t gfp_mask,
4649					    unsigned long *total_scanned)
4650{
4651	unsigned long nr_reclaimed = 0;
4652	struct mem_cgroup_per_zone *mz, *next_mz = NULL;
4653	unsigned long reclaimed;
4654	int loop = 0;
4655	struct mem_cgroup_tree_per_zone *mctz;
4656	unsigned long long excess;
4657	unsigned long nr_scanned;
 
 
4658
4659	if (order > 0)
4660		return 0;
4661
4662	mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
 
 
 
 
 
 
 
 
 
4663	/*
4664	 * This loop can run a while, specially if mem_cgroup's continuously
4665	 * keep exceeding their soft limit and putting the system under
4666	 * pressure
4667	 */
4668	do {
4669		if (next_mz)
4670			mz = next_mz;
4671		else
4672			mz = mem_cgroup_largest_soft_limit_node(mctz);
4673		if (!mz)
4674			break;
4675
4676		nr_scanned = 0;
4677		reclaimed = mem_cgroup_soft_reclaim(mz->memcg, zone,
4678						    gfp_mask, &nr_scanned);
4679		nr_reclaimed += reclaimed;
4680		*total_scanned += nr_scanned;
4681		spin_lock(&mctz->lock);
4682
4683		/*
4684		 * If we failed to reclaim anything from this memory cgroup
4685		 * it is time to move on to the next cgroup
4686		 */
4687		next_mz = NULL;
4688		if (!reclaimed) {
4689			do {
4690				/*
4691				 * Loop until we find yet another one.
4692				 *
4693				 * By the time we get the soft_limit lock
4694				 * again, someone might have aded the
4695				 * group back on the RB tree. Iterate to
4696				 * make sure we get a different mem.
4697				 * mem_cgroup_largest_soft_limit_node returns
4698				 * NULL if no other cgroup is present on
4699				 * the tree
4700				 */
4701				next_mz =
4702				__mem_cgroup_largest_soft_limit_node(mctz);
4703				if (next_mz == mz)
4704					css_put(&next_mz->memcg->css);
4705				else /* next_mz == NULL or other memcg */
4706					break;
4707			} while (1);
4708		}
4709		__mem_cgroup_remove_exceeded(mz->memcg, mz, mctz);
4710		excess = res_counter_soft_limit_excess(&mz->memcg->res);
4711		/*
4712		 * One school of thought says that we should not add
4713		 * back the node to the tree if reclaim returns 0.
4714		 * But our reclaim could return 0, simply because due
4715		 * to priority we are exposing a smaller subset of
4716		 * memory to reclaim from. Consider this as a longer
4717		 * term TODO.
4718		 */
4719		/* If excess == 0, no tree ops */
4720		__mem_cgroup_insert_exceeded(mz->memcg, mz, mctz, excess);
4721		spin_unlock(&mctz->lock);
4722		css_put(&mz->memcg->css);
4723		loop++;
4724		/*
4725		 * Could not reclaim anything and there are no more
4726		 * mem cgroups to try or we seem to be looping without
4727		 * reclaiming anything.
4728		 */
4729		if (!nr_reclaimed &&
4730			(next_mz == NULL ||
4731			loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
4732			break;
4733	} while (!nr_reclaimed);
4734	if (next_mz)
4735		css_put(&next_mz->memcg->css);
4736	return nr_reclaimed;
4737}
4738
4739/**
4740 * mem_cgroup_force_empty_list - clears LRU of a group
4741 * @memcg: group to clear
4742 * @node: NUMA node
4743 * @zid: zone id
4744 * @lru: lru to to clear
4745 *
4746 * Traverse a specified page_cgroup list and try to drop them all.  This doesn't
4747 * reclaim the pages page themselves - pages are moved to the parent (or root)
4748 * group.
4749 */
4750static void mem_cgroup_force_empty_list(struct mem_cgroup *memcg,
4751				int node, int zid, enum lru_list lru)
4752{
4753	struct lruvec *lruvec;
4754	unsigned long flags;
4755	struct list_head *list;
4756	struct page *busy;
4757	struct zone *zone;
4758
4759	zone = &NODE_DATA(node)->node_zones[zid];
4760	lruvec = mem_cgroup_zone_lruvec(zone, memcg);
4761	list = &lruvec->lists[lru];
4762
4763	busy = NULL;
4764	do {
4765		struct page_cgroup *pc;
4766		struct page *page;
4767
4768		spin_lock_irqsave(&zone->lru_lock, flags);
4769		if (list_empty(list)) {
4770			spin_unlock_irqrestore(&zone->lru_lock, flags);
4771			break;
4772		}
4773		page = list_entry(list->prev, struct page, lru);
4774		if (busy == page) {
4775			list_move(&page->lru, list);
4776			busy = NULL;
4777			spin_unlock_irqrestore(&zone->lru_lock, flags);
4778			continue;
4779		}
4780		spin_unlock_irqrestore(&zone->lru_lock, flags);
4781
4782		pc = lookup_page_cgroup(page);
4783
4784		if (mem_cgroup_move_parent(page, pc, memcg)) {
4785			/* found lock contention or "pc" is obsolete. */
4786			busy = page;
4787			cond_resched();
4788		} else
4789			busy = NULL;
4790	} while (!list_empty(list));
4791}
4792
4793/*
4794 * make mem_cgroup's charge to be 0 if there is no task by moving
4795 * all the charges and pages to the parent.
4796 * This enables deleting this mem_cgroup.
4797 *
4798 * Caller is responsible for holding css reference on the memcg.
4799 */
4800static void mem_cgroup_reparent_charges(struct mem_cgroup *memcg)
4801{
4802	int node, zid;
4803	u64 usage;
4804
4805	do {
4806		/* This is for making all *used* pages to be on LRU. */
4807		lru_add_drain_all();
4808		drain_all_stock_sync(memcg);
4809		mem_cgroup_start_move(memcg);
4810		for_each_node_state(node, N_MEMORY) {
4811			for (zid = 0; zid < MAX_NR_ZONES; zid++) {
4812				enum lru_list lru;
4813				for_each_lru(lru) {
4814					mem_cgroup_force_empty_list(memcg,
4815							node, zid, lru);
4816				}
4817			}
4818		}
4819		mem_cgroup_end_move(memcg);
4820		memcg_oom_recover(memcg);
4821		cond_resched();
4822
4823		/*
4824		 * Kernel memory may not necessarily be trackable to a specific
4825		 * process. So they are not migrated, and therefore we can't
4826		 * expect their value to drop to 0 here.
4827		 * Having res filled up with kmem only is enough.
4828		 *
4829		 * This is a safety check because mem_cgroup_force_empty_list
4830		 * could have raced with mem_cgroup_replace_page_cache callers
4831		 * so the lru seemed empty but the page could have been added
4832		 * right after the check. RES_USAGE should be safe as we always
4833		 * charge before adding to the LRU.
4834		 */
4835		usage = res_counter_read_u64(&memcg->res, RES_USAGE) -
4836			res_counter_read_u64(&memcg->kmem, RES_USAGE);
4837	} while (usage > 0);
4838}
4839
4840static inline bool memcg_has_children(struct mem_cgroup *memcg)
4841{
4842	lockdep_assert_held(&memcg_create_mutex);
4843	/*
4844	 * The lock does not prevent addition or deletion to the list
4845	 * of children, but it prevents a new child from being
4846	 * initialized based on this parent in css_online(), so it's
4847	 * enough to decide whether hierarchically inherited
4848	 * attributes can still be changed or not.
4849	 */
4850	return memcg->use_hierarchy &&
4851		!list_empty(&memcg->css.cgroup->children);
4852}
4853
4854/*
4855 * Reclaims as many pages from the given memcg as possible and moves
4856 * the rest to the parent.
4857 *
4858 * Caller is responsible for holding css reference for memcg.
4859 */
4860static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
4861{
4862	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
4863	struct cgroup *cgrp = memcg->css.cgroup;
4864
4865	/* returns EBUSY if there is a task or if we come here twice. */
4866	if (cgroup_has_tasks(cgrp) || !list_empty(&cgrp->children))
4867		return -EBUSY;
4868
4869	/* we call try-to-free pages for make this cgroup empty */
4870	lru_add_drain_all();
4871	/* try to free all pages in this cgroup */
4872	while (nr_retries && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) {
4873		int progress;
4874
 
 
 
 
4875		if (signal_pending(current))
4876			return -EINTR;
4877
4878		progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL,
4879						false);
4880		if (!progress) {
4881			nr_retries--;
4882			/* maybe some writeback is necessary */
4883			congestion_wait(BLK_RW_ASYNC, HZ/10);
4884		}
4885
4886	}
4887	lru_add_drain();
4888	mem_cgroup_reparent_charges(memcg);
4889
4890	return 0;
4891}
4892
4893static int mem_cgroup_force_empty_write(struct cgroup_subsys_state *css,
4894					unsigned int event)
 
4895{
4896	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4897
4898	if (mem_cgroup_is_root(memcg))
4899		return -EINVAL;
4900	return mem_cgroup_force_empty(memcg);
4901}
4902
4903static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
4904				     struct cftype *cft)
4905{
4906	return mem_cgroup_from_css(css)->use_hierarchy;
4907}
4908
4909static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
4910				      struct cftype *cft, u64 val)
4911{
4912	int retval = 0;
4913	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4914	struct mem_cgroup *parent_memcg = mem_cgroup_from_css(css_parent(&memcg->css));
4915
4916	mutex_lock(&memcg_create_mutex);
4917
4918	if (memcg->use_hierarchy == val)
4919		goto out;
4920
4921	/*
4922	 * If parent's use_hierarchy is set, we can't make any modifications
4923	 * in the child subtrees. If it is unset, then the change can
4924	 * occur, provided the current cgroup has no children.
4925	 *
4926	 * For the root cgroup, parent_mem is NULL, we allow value to be
4927	 * set if there are no children.
4928	 */
4929	if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
4930				(val == 1 || val == 0)) {
4931		if (list_empty(&memcg->css.cgroup->children))
4932			memcg->use_hierarchy = val;
4933		else
4934			retval = -EBUSY;
4935	} else
4936		retval = -EINVAL;
4937
4938out:
4939	mutex_unlock(&memcg_create_mutex);
4940
4941	return retval;
4942}
4943
4944
4945static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *memcg,
4946					       enum mem_cgroup_stat_index idx)
4947{
4948	struct mem_cgroup *iter;
4949	long val = 0;
4950
4951	/* Per-cpu values can be negative, use a signed accumulator */
4952	for_each_mem_cgroup_tree(iter, memcg)
4953		val += mem_cgroup_read_stat(iter, idx);
4954
4955	if (val < 0) /* race ? */
4956		val = 0;
4957	return val;
4958}
4959
4960static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
4961{
4962	u64 val;
4963
4964	if (!mem_cgroup_is_root(memcg)) {
 
 
 
 
 
 
 
 
 
4965		if (!swap)
4966			return res_counter_read_u64(&memcg->res, RES_USAGE);
4967		else
4968			return res_counter_read_u64(&memcg->memsw, RES_USAGE);
4969	}
4970
4971	/*
4972	 * Transparent hugepages are still accounted for in MEM_CGROUP_STAT_RSS
4973	 * as well as in MEM_CGROUP_STAT_RSS_HUGE.
4974	 */
4975	val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE);
4976	val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS);
4977
4978	if (swap)
4979		val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAP);
4980
4981	return val << PAGE_SHIFT;
4982}
4983
 
 
 
 
 
 
 
 
4984static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
4985				   struct cftype *cft)
4986{
4987	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4988	u64 val;
4989	int name;
4990	enum res_type type;
4991
4992	type = MEMFILE_TYPE(cft->private);
4993	name = MEMFILE_ATTR(cft->private);
4994
4995	switch (type) {
4996	case _MEM:
4997		if (name == RES_USAGE)
4998			val = mem_cgroup_usage(memcg, false);
4999		else
5000			val = res_counter_read_u64(&memcg->res, name);
5001		break;
5002	case _MEMSWAP:
5003		if (name == RES_USAGE)
5004			val = mem_cgroup_usage(memcg, true);
5005		else
5006			val = res_counter_read_u64(&memcg->memsw, name);
5007		break;
5008	case _KMEM:
5009		val = res_counter_read_u64(&memcg->kmem, name);
 
 
 
5010		break;
5011	default:
5012		BUG();
5013	}
5014
5015	return val;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5016}
5017
5018#ifdef CONFIG_MEMCG_KMEM
5019/* should be called with activate_kmem_mutex held */
5020static int __memcg_activate_kmem(struct mem_cgroup *memcg,
5021				 unsigned long long limit)
5022{
5023	int err = 0;
5024	int memcg_id;
5025
5026	if (memcg_kmem_is_active(memcg))
5027		return 0;
5028
5029	/*
5030	 * We are going to allocate memory for data shared by all memory
5031	 * cgroups so let's stop accounting here.
5032	 */
5033	memcg_stop_kmem_account();
5034
5035	/*
5036	 * For simplicity, we won't allow this to be disabled.  It also can't
5037	 * be changed if the cgroup has children already, or if tasks had
5038	 * already joined.
5039	 *
5040	 * If tasks join before we set the limit, a person looking at
5041	 * kmem.usage_in_bytes will have no way to determine when it took
5042	 * place, which makes the value quite meaningless.
5043	 *
5044	 * After it first became limited, changes in the value of the limit are
5045	 * of course permitted.
5046	 */
5047	mutex_lock(&memcg_create_mutex);
5048	if (cgroup_has_tasks(memcg->css.cgroup) || memcg_has_children(memcg))
5049		err = -EBUSY;
5050	mutex_unlock(&memcg_create_mutex);
5051	if (err)
5052		goto out;
5053
5054	memcg_id = ida_simple_get(&kmem_limited_groups,
5055				  0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
5056	if (memcg_id < 0) {
5057		err = memcg_id;
5058		goto out;
5059	}
5060
5061	/*
5062	 * Make sure we have enough space for this cgroup in each root cache's
5063	 * memcg_params.
5064	 */
5065	err = memcg_update_all_caches(memcg_id + 1);
5066	if (err)
5067		goto out_rmid;
5068
5069	memcg->kmemcg_id = memcg_id;
5070	INIT_LIST_HEAD(&memcg->memcg_slab_caches);
5071	mutex_init(&memcg->slab_caches_mutex);
5072
5073	/*
5074	 * We couldn't have accounted to this cgroup, because it hasn't got the
5075	 * active bit set yet, so this should succeed.
5076	 */
5077	err = res_counter_set_limit(&memcg->kmem, limit);
5078	VM_BUG_ON(err);
5079
5080	static_key_slow_inc(&memcg_kmem_enabled_key);
5081	/*
5082	 * Setting the active bit after enabling static branching will
5083	 * guarantee no one starts accounting before all call sites are
5084	 * patched.
5085	 */
5086	memcg_kmem_set_active(memcg);
5087out:
5088	memcg_resume_kmem_account();
5089	return err;
5090
5091out_rmid:
5092	ida_simple_remove(&kmem_limited_groups, memcg_id);
5093	goto out;
5094}
5095
5096static int memcg_activate_kmem(struct mem_cgroup *memcg,
5097			       unsigned long long limit)
5098{
5099	int ret;
5100
5101	mutex_lock(&activate_kmem_mutex);
5102	ret = __memcg_activate_kmem(memcg, limit);
5103	mutex_unlock(&activate_kmem_mutex);
5104	return ret;
5105}
5106
5107static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
5108				   unsigned long long val)
5109{
5110	int ret;
5111
5112	if (!memcg_kmem_is_active(memcg))
5113		ret = memcg_activate_kmem(memcg, val);
5114	else
5115		ret = res_counter_set_limit(&memcg->kmem, val);
5116	return ret;
5117}
5118
5119static int memcg_propagate_kmem(struct mem_cgroup *memcg)
5120{
5121	int ret = 0;
5122	struct mem_cgroup *parent = parent_mem_cgroup(memcg);
5123
 
5124	if (!parent)
5125		return 0;
 
 
5126
5127	mutex_lock(&activate_kmem_mutex);
5128	/*
5129	 * If the parent cgroup is not kmem-active now, it cannot be activated
5130	 * after this point, because it has at least one child already.
 
 
5131	 */
5132	if (memcg_kmem_is_active(parent))
5133		ret = __memcg_activate_kmem(memcg, RES_COUNTER_MAX);
5134	mutex_unlock(&activate_kmem_mutex);
5135	return ret;
5136}
5137#else
5138static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
5139				   unsigned long long val)
 
 
 
5140{
5141	return -EINVAL;
5142}
5143#endif /* CONFIG_MEMCG_KMEM */
5144
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5145/*
5146 * The user of this function is...
5147 * RES_LIMIT.
5148 */
5149static int mem_cgroup_write(struct cgroup_subsys_state *css, struct cftype *cft,
5150			    char *buffer)
5151{
5152	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5153	enum res_type type;
5154	int name;
5155	unsigned long long val;
5156	int ret;
5157
5158	type = MEMFILE_TYPE(cft->private);
5159	name = MEMFILE_ATTR(cft->private);
 
 
5160
5161	switch (name) {
5162	case RES_LIMIT:
5163		if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
5164			ret = -EINVAL;
5165			break;
5166		}
5167		/* This function does all necessary parse...reuse it */
5168		ret = res_counter_memparse_write_strategy(buffer, &val);
5169		if (ret)
5170			break;
5171		if (type == _MEM)
5172			ret = mem_cgroup_resize_limit(memcg, val);
5173		else if (type == _MEMSWAP)
5174			ret = mem_cgroup_resize_memsw_limit(memcg, val);
5175		else if (type == _KMEM)
5176			ret = memcg_update_kmem_limit(memcg, val);
5177		else
5178			return -EINVAL;
5179		break;
5180	case RES_SOFT_LIMIT:
5181		ret = res_counter_memparse_write_strategy(buffer, &val);
5182		if (ret)
5183			break;
5184		/*
5185		 * For memsw, soft limits are hard to implement in terms
5186		 * of semantics, for now, we support soft limits for
5187		 * control without swap
5188		 */
5189		if (type == _MEM)
5190			ret = res_counter_set_soft_limit(&memcg->res, val);
5191		else
5192			ret = -EINVAL;
 
 
5193		break;
5194	default:
5195		ret = -EINVAL; /* should be BUG() ? */
 
 
 
 
 
5196		break;
5197	}
5198	return ret;
5199}
5200
5201static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
5202		unsigned long long *mem_limit, unsigned long long *memsw_limit)
5203{
5204	unsigned long long min_limit, min_memsw_limit, tmp;
 
5205
5206	min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
5207	min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
5208	if (!memcg->use_hierarchy)
5209		goto out;
5210
5211	while (css_parent(&memcg->css)) {
5212		memcg = mem_cgroup_from_css(css_parent(&memcg->css));
5213		if (!memcg->use_hierarchy)
5214			break;
5215		tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
5216		min_limit = min(min_limit, tmp);
5217		tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
5218		min_memsw_limit = min(min_memsw_limit, tmp);
 
 
5219	}
5220out:
5221	*mem_limit = min_limit;
5222	*memsw_limit = min_memsw_limit;
5223}
5224
5225static int mem_cgroup_reset(struct cgroup_subsys_state *css, unsigned int event)
5226{
5227	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5228	int name;
5229	enum res_type type;
5230
5231	type = MEMFILE_TYPE(event);
5232	name = MEMFILE_ATTR(event);
5233
5234	switch (name) {
5235	case RES_MAX_USAGE:
5236		if (type == _MEM)
5237			res_counter_reset_max(&memcg->res);
5238		else if (type == _MEMSWAP)
5239			res_counter_reset_max(&memcg->memsw);
5240		else if (type == _KMEM)
5241			res_counter_reset_max(&memcg->kmem);
5242		else
5243			return -EINVAL;
5244		break;
5245	case RES_FAILCNT:
5246		if (type == _MEM)
5247			res_counter_reset_failcnt(&memcg->res);
5248		else if (type == _MEMSWAP)
5249			res_counter_reset_failcnt(&memcg->memsw);
5250		else if (type == _KMEM)
5251			res_counter_reset_failcnt(&memcg->kmem);
5252		else
5253			return -EINVAL;
5254		break;
 
 
5255	}
5256
5257	return 0;
5258}
5259
5260static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
5261					struct cftype *cft)
5262{
5263	return mem_cgroup_from_css(css)->move_charge_at_immigrate;
5264}
5265
5266#ifdef CONFIG_MMU
5267static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
5268					struct cftype *cft, u64 val)
5269{
5270	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5271
5272	if (val >= (1 << NR_MOVE_TYPE))
 
 
 
 
5273		return -EINVAL;
5274
5275	/*
5276	 * No kind of locking is needed in here, because ->can_attach() will
5277	 * check this value once in the beginning of the process, and then carry
5278	 * on with stale data. This means that changes to this value will only
5279	 * affect task migrations starting after the change.
5280	 */
5281	memcg->move_charge_at_immigrate = val;
5282	return 0;
5283}
5284#else
5285static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
5286					struct cftype *cft, u64 val)
5287{
5288	return -ENOSYS;
5289}
5290#endif
5291
5292#ifdef CONFIG_NUMA
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5293static int memcg_numa_stat_show(struct seq_file *m, void *v)
5294{
5295	struct numa_stat {
5296		const char *name;
5297		unsigned int lru_mask;
5298	};
5299
5300	static const struct numa_stat stats[] = {
5301		{ "total", LRU_ALL },
5302		{ "file", LRU_ALL_FILE },
5303		{ "anon", LRU_ALL_ANON },
5304		{ "unevictable", BIT(LRU_UNEVICTABLE) },
5305	};
5306	const struct numa_stat *stat;
5307	int nid;
5308	unsigned long nr;
5309	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
 
5310
5311	for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
5312		nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask);
5313		seq_printf(m, "%s=%lu", stat->name, nr);
5314		for_each_node_state(nid, N_MEMORY) {
5315			nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
5316							  stat->lru_mask);
5317			seq_printf(m, " N%d=%lu", nid, nr);
5318		}
5319		seq_putc(m, '\n');
5320	}
5321
5322	for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
5323		struct mem_cgroup *iter;
5324
5325		nr = 0;
5326		for_each_mem_cgroup_tree(iter, memcg)
5327			nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask);
5328		seq_printf(m, "hierarchical_%s=%lu", stat->name, nr);
5329		for_each_node_state(nid, N_MEMORY) {
5330			nr = 0;
5331			for_each_mem_cgroup_tree(iter, memcg)
5332				nr += mem_cgroup_node_nr_lru_pages(
5333					iter, nid, stat->lru_mask);
5334			seq_printf(m, " N%d=%lu", nid, nr);
5335		}
5336		seq_putc(m, '\n');
5337	}
5338
5339	return 0;
5340}
5341#endif /* CONFIG_NUMA */
5342
5343static inline void mem_cgroup_lru_names_not_uptodate(void)
5344{
5345	BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
5346}
 
 
 
 
 
 
 
 
 
 
 
 
 
5347
5348static int memcg_stat_show(struct seq_file *m, void *v)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5349{
5350	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
5351	struct mem_cgroup *mi;
5352	unsigned int i;
5353
5354	for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
5355		if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
5356			continue;
5357		seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i],
5358			   mem_cgroup_read_stat(memcg, i) * PAGE_SIZE);
5359	}
5360
5361	for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++)
5362		seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i],
5363			   mem_cgroup_read_events(memcg, i));
5364
5365	for (i = 0; i < NR_LRU_LISTS; i++)
5366		seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
5367			   mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE);
5368
5369	/* Hierarchical information */
5370	{
5371		unsigned long long limit, memsw_limit;
5372		memcg_get_hierarchical_limit(memcg, &limit, &memsw_limit);
5373		seq_printf(m, "hierarchical_memory_limit %llu\n", limit);
5374		if (do_swap_account)
5375			seq_printf(m, "hierarchical_memsw_limit %llu\n",
5376				   memsw_limit);
5377	}
5378
5379	for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
5380		long long val = 0;
5381
5382		if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
5383			continue;
5384		for_each_mem_cgroup_tree(mi, memcg)
5385			val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE;
5386		seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val);
5387	}
5388
5389	for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
5390		unsigned long long val = 0;
 
5391
5392		for_each_mem_cgroup_tree(mi, memcg)
5393			val += mem_cgroup_read_events(mi, i);
5394		seq_printf(m, "total_%s %llu\n",
5395			   mem_cgroup_events_names[i], val);
5396	}
5397
5398	for (i = 0; i < NR_LRU_LISTS; i++) {
5399		unsigned long long val = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5400
5401		for_each_mem_cgroup_tree(mi, memcg)
5402			val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE;
5403		seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val);
5404	}
5405
5406#ifdef CONFIG_DEBUG_VM
5407	{
5408		int nid, zid;
5409		struct mem_cgroup_per_zone *mz;
5410		struct zone_reclaim_stat *rstat;
5411		unsigned long recent_rotated[2] = {0, 0};
5412		unsigned long recent_scanned[2] = {0, 0};
5413
5414		for_each_online_node(nid)
5415			for (zid = 0; zid < MAX_NR_ZONES; zid++) {
5416				mz = mem_cgroup_zoneinfo(memcg, nid, zid);
5417				rstat = &mz->lruvec.reclaim_stat;
5418
5419				recent_rotated[0] += rstat->recent_rotated[0];
5420				recent_rotated[1] += rstat->recent_rotated[1];
5421				recent_scanned[0] += rstat->recent_scanned[0];
5422				recent_scanned[1] += rstat->recent_scanned[1];
5423			}
5424		seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
5425		seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
5426		seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
5427		seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
5428	}
5429#endif
5430
5431	return 0;
5432}
5433
5434static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
5435				      struct cftype *cft)
5436{
5437	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5438
5439	return mem_cgroup_swappiness(memcg);
5440}
5441
5442static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
5443				       struct cftype *cft, u64 val)
5444{
5445	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5446	struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(&memcg->css));
5447
5448	if (val > 100 || !parent)
5449		return -EINVAL;
5450
5451	mutex_lock(&memcg_create_mutex);
5452
5453	/* If under hierarchy, only empty-root can set this value */
5454	if ((parent->use_hierarchy) || memcg_has_children(memcg)) {
5455		mutex_unlock(&memcg_create_mutex);
5456		return -EINVAL;
5457	}
5458
5459	memcg->swappiness = val;
5460
5461	mutex_unlock(&memcg_create_mutex);
5462
5463	return 0;
5464}
5465
5466static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
5467{
5468	struct mem_cgroup_threshold_ary *t;
5469	u64 usage;
5470	int i;
5471
5472	rcu_read_lock();
5473	if (!swap)
5474		t = rcu_dereference(memcg->thresholds.primary);
5475	else
5476		t = rcu_dereference(memcg->memsw_thresholds.primary);
5477
5478	if (!t)
5479		goto unlock;
5480
5481	usage = mem_cgroup_usage(memcg, swap);
5482
5483	/*
5484	 * current_threshold points to threshold just below or equal to usage.
5485	 * If it's not true, a threshold was crossed after last
5486	 * call of __mem_cgroup_threshold().
5487	 */
5488	i = t->current_threshold;
5489
5490	/*
5491	 * Iterate backward over array of thresholds starting from
5492	 * current_threshold and check if a threshold is crossed.
5493	 * If none of thresholds below usage is crossed, we read
5494	 * only one element of the array here.
5495	 */
5496	for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
5497		eventfd_signal(t->entries[i].eventfd, 1);
5498
5499	/* i = current_threshold + 1 */
5500	i++;
5501
5502	/*
5503	 * Iterate forward over array of thresholds starting from
5504	 * current_threshold+1 and check if a threshold is crossed.
5505	 * If none of thresholds above usage is crossed, we read
5506	 * only one element of the array here.
5507	 */
5508	for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
5509		eventfd_signal(t->entries[i].eventfd, 1);
5510
5511	/* Update current_threshold */
5512	t->current_threshold = i - 1;
5513unlock:
5514	rcu_read_unlock();
5515}
5516
5517static void mem_cgroup_threshold(struct mem_cgroup *memcg)
5518{
5519	while (memcg) {
5520		__mem_cgroup_threshold(memcg, false);
5521		if (do_swap_account)
5522			__mem_cgroup_threshold(memcg, true);
5523
5524		memcg = parent_mem_cgroup(memcg);
5525	}
5526}
5527
5528static int compare_thresholds(const void *a, const void *b)
5529{
5530	const struct mem_cgroup_threshold *_a = a;
5531	const struct mem_cgroup_threshold *_b = b;
5532
5533	if (_a->threshold > _b->threshold)
5534		return 1;
5535
5536	if (_a->threshold < _b->threshold)
5537		return -1;
5538
5539	return 0;
5540}
5541
5542static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
5543{
5544	struct mem_cgroup_eventfd_list *ev;
5545
 
 
5546	list_for_each_entry(ev, &memcg->oom_notify, list)
5547		eventfd_signal(ev->eventfd, 1);
 
 
5548	return 0;
5549}
5550
5551static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
5552{
5553	struct mem_cgroup *iter;
5554
5555	for_each_mem_cgroup_tree(iter, memcg)
5556		mem_cgroup_oom_notify_cb(iter);
5557}
5558
5559static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
5560	struct eventfd_ctx *eventfd, const char *args, enum res_type type)
5561{
5562	struct mem_cgroup_thresholds *thresholds;
5563	struct mem_cgroup_threshold_ary *new;
5564	u64 threshold, usage;
 
5565	int i, size, ret;
5566
5567	ret = res_counter_memparse_write_strategy(args, &threshold);
5568	if (ret)
5569		return ret;
5570
5571	mutex_lock(&memcg->thresholds_lock);
5572
5573	if (type == _MEM)
5574		thresholds = &memcg->thresholds;
5575	else if (type == _MEMSWAP)
 
5576		thresholds = &memcg->memsw_thresholds;
5577	else
 
5578		BUG();
5579
5580	usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
5581
5582	/* Check if a threshold crossed before adding a new one */
5583	if (thresholds->primary)
5584		__mem_cgroup_threshold(memcg, type == _MEMSWAP);
5585
5586	size = thresholds->primary ? thresholds->primary->size + 1 : 1;
5587
5588	/* Allocate memory for new array of thresholds */
5589	new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
5590			GFP_KERNEL);
5591	if (!new) {
5592		ret = -ENOMEM;
5593		goto unlock;
5594	}
5595	new->size = size;
5596
5597	/* Copy thresholds (if any) to new array */
5598	if (thresholds->primary) {
5599		memcpy(new->entries, thresholds->primary->entries, (size - 1) *
5600				sizeof(struct mem_cgroup_threshold));
5601	}
5602
5603	/* Add new threshold */
5604	new->entries[size - 1].eventfd = eventfd;
5605	new->entries[size - 1].threshold = threshold;
5606
5607	/* Sort thresholds. Registering of new threshold isn't time-critical */
5608	sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
5609			compare_thresholds, NULL);
5610
5611	/* Find current threshold */
5612	new->current_threshold = -1;
5613	for (i = 0; i < size; i++) {
5614		if (new->entries[i].threshold <= usage) {
5615			/*
5616			 * new->current_threshold will not be used until
5617			 * rcu_assign_pointer(), so it's safe to increment
5618			 * it here.
5619			 */
5620			++new->current_threshold;
5621		} else
5622			break;
5623	}
5624
5625	/* Free old spare buffer and save old primary buffer as spare */
5626	kfree(thresholds->spare);
5627	thresholds->spare = thresholds->primary;
5628
5629	rcu_assign_pointer(thresholds->primary, new);
5630
5631	/* To be sure that nobody uses thresholds */
5632	synchronize_rcu();
5633
5634unlock:
5635	mutex_unlock(&memcg->thresholds_lock);
5636
5637	return ret;
5638}
5639
5640static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
5641	struct eventfd_ctx *eventfd, const char *args)
5642{
5643	return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM);
5644}
5645
5646static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg,
5647	struct eventfd_ctx *eventfd, const char *args)
5648{
5649	return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP);
5650}
5651
5652static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
5653	struct eventfd_ctx *eventfd, enum res_type type)
5654{
5655	struct mem_cgroup_thresholds *thresholds;
5656	struct mem_cgroup_threshold_ary *new;
5657	u64 usage;
5658	int i, j, size;
5659
5660	mutex_lock(&memcg->thresholds_lock);
5661	if (type == _MEM)
 
5662		thresholds = &memcg->thresholds;
5663	else if (type == _MEMSWAP)
 
5664		thresholds = &memcg->memsw_thresholds;
5665	else
 
5666		BUG();
5667
5668	if (!thresholds->primary)
5669		goto unlock;
5670
5671	usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
5672
5673	/* Check if a threshold crossed before removing */
5674	__mem_cgroup_threshold(memcg, type == _MEMSWAP);
5675
5676	/* Calculate new number of threshold */
5677	size = 0;
5678	for (i = 0; i < thresholds->primary->size; i++) {
5679		if (thresholds->primary->entries[i].eventfd != eventfd)
5680			size++;
 
 
5681	}
5682
5683	new = thresholds->spare;
5684
 
 
 
 
5685	/* Set thresholds array to NULL if we don't have thresholds */
5686	if (!size) {
5687		kfree(new);
5688		new = NULL;
5689		goto swap_buffers;
5690	}
5691
5692	new->size = size;
5693
5694	/* Copy thresholds and find current threshold */
5695	new->current_threshold = -1;
5696	for (i = 0, j = 0; i < thresholds->primary->size; i++) {
5697		if (thresholds->primary->entries[i].eventfd == eventfd)
5698			continue;
5699
5700		new->entries[j] = thresholds->primary->entries[i];
5701		if (new->entries[j].threshold <= usage) {
5702			/*
5703			 * new->current_threshold will not be used
5704			 * until rcu_assign_pointer(), so it's safe to increment
5705			 * it here.
5706			 */
5707			++new->current_threshold;
5708		}
5709		j++;
5710	}
5711
5712swap_buffers:
5713	/* Swap primary and spare array */
5714	thresholds->spare = thresholds->primary;
5715	/* If all events are unregistered, free the spare array */
5716	if (!new) {
5717		kfree(thresholds->spare);
5718		thresholds->spare = NULL;
5719	}
5720
5721	rcu_assign_pointer(thresholds->primary, new);
5722
5723	/* To be sure that nobody uses thresholds */
5724	synchronize_rcu();
 
 
 
 
 
 
5725unlock:
5726	mutex_unlock(&memcg->thresholds_lock);
5727}
5728
5729static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
5730	struct eventfd_ctx *eventfd)
5731{
5732	return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM);
5733}
5734
5735static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
5736	struct eventfd_ctx *eventfd)
5737{
5738	return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP);
5739}
5740
5741static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
5742	struct eventfd_ctx *eventfd, const char *args)
5743{
5744	struct mem_cgroup_eventfd_list *event;
5745
5746	event = kmalloc(sizeof(*event),	GFP_KERNEL);
5747	if (!event)
5748		return -ENOMEM;
5749
5750	spin_lock(&memcg_oom_lock);
5751
5752	event->eventfd = eventfd;
5753	list_add(&event->list, &memcg->oom_notify);
5754
5755	/* already in OOM ? */
5756	if (atomic_read(&memcg->under_oom))
5757		eventfd_signal(eventfd, 1);
5758	spin_unlock(&memcg_oom_lock);
5759
5760	return 0;
5761}
5762
5763static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg,
5764	struct eventfd_ctx *eventfd)
5765{
5766	struct mem_cgroup_eventfd_list *ev, *tmp;
5767
5768	spin_lock(&memcg_oom_lock);
5769
5770	list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
5771		if (ev->eventfd == eventfd) {
5772			list_del(&ev->list);
5773			kfree(ev);
5774		}
5775	}
5776
5777	spin_unlock(&memcg_oom_lock);
5778}
5779
5780static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v)
5781{
5782	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(sf));
5783
5784	seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable);
5785	seq_printf(sf, "under_oom %d\n", (bool)atomic_read(&memcg->under_oom));
 
 
5786	return 0;
5787}
5788
5789static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css,
5790	struct cftype *cft, u64 val)
5791{
5792	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5793	struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(&memcg->css));
5794
5795	/* cannot set to root cgroup and only 0 and 1 are allowed */
5796	if (!parent || !((val == 0) || (val == 1)))
5797		return -EINVAL;
5798
5799	mutex_lock(&memcg_create_mutex);
5800	/* oom-kill-disable is a flag for subhierarchy. */
5801	if ((parent->use_hierarchy) || memcg_has_children(memcg)) {
5802		mutex_unlock(&memcg_create_mutex);
5803		return -EINVAL;
5804	}
5805	memcg->oom_kill_disable = val;
5806	if (!val)
5807		memcg_oom_recover(memcg);
5808	mutex_unlock(&memcg_create_mutex);
5809	return 0;
5810}
5811
5812#ifdef CONFIG_MEMCG_KMEM
5813static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
 
 
 
5814{
5815	int ret;
 
5816
5817	memcg->kmemcg_id = -1;
5818	ret = memcg_propagate_kmem(memcg);
5819	if (ret)
5820		return ret;
5821
5822	return mem_cgroup_sockets_init(memcg, ss);
 
 
5823}
5824
5825static void memcg_destroy_kmem(struct mem_cgroup *memcg)
5826{
5827	mem_cgroup_sockets_destroy(memcg);
 
 
 
 
 
5828}
5829
5830static void kmem_cgroup_css_offline(struct mem_cgroup *memcg)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5831{
5832	if (!memcg_kmem_is_active(memcg))
5833		return;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5834
5835	/*
5836	 * kmem charges can outlive the cgroup. In the case of slab
5837	 * pages, for instance, a page contain objects from various
5838	 * processes. As we prevent from taking a reference for every
5839	 * such allocation we have to be careful when doing uncharge
5840	 * (see memcg_uncharge_kmem) and here during offlining.
5841	 *
5842	 * The idea is that that only the _last_ uncharge which sees
5843	 * the dead memcg will drop the last reference. An additional
5844	 * reference is taken here before the group is marked dead
5845	 * which is then paired with css_put during uncharge resp. here.
5846	 *
5847	 * Although this might sound strange as this path is called from
5848	 * css_offline() when the referencemight have dropped down to 0
5849	 * and shouldn't be incremented anymore (css_tryget would fail)
5850	 * we do not have other options because of the kmem allocations
5851	 * lifetime.
5852	 */
5853	css_get(&memcg->css);
 
 
 
 
 
 
 
 
 
 
5854
5855	memcg_kmem_mark_dead(memcg);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5856
5857	if (res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0)
5858		return;
 
 
 
 
 
5859
5860	if (memcg_kmem_test_and_clear_dead(memcg))
5861		css_put(&memcg->css);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5862}
5863#else
5864static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
 
 
5865{
5866	return 0;
5867}
5868
5869static void memcg_destroy_kmem(struct mem_cgroup *memcg)
5870{
5871}
5872
5873static void kmem_cgroup_css_offline(struct mem_cgroup *memcg)
5874{
5875}
5876#endif
 
5877
5878/*
5879 * DO NOT USE IN NEW FILES.
5880 *
5881 * "cgroup.event_control" implementation.
5882 *
5883 * This is way over-engineered.  It tries to support fully configurable
5884 * events for each user.  Such level of flexibility is completely
5885 * unnecessary especially in the light of the planned unified hierarchy.
5886 *
5887 * Please deprecate this and replace with something simpler if at all
5888 * possible.
5889 */
5890
5891/*
5892 * Unregister event and free resources.
5893 *
5894 * Gets called from workqueue.
5895 */
5896static void memcg_event_remove(struct work_struct *work)
5897{
5898	struct mem_cgroup_event *event =
5899		container_of(work, struct mem_cgroup_event, remove);
5900	struct mem_cgroup *memcg = event->memcg;
5901
5902	remove_wait_queue(event->wqh, &event->wait);
5903
5904	event->unregister_event(memcg, event->eventfd);
5905
5906	/* Notify userspace the event is going away. */
5907	eventfd_signal(event->eventfd, 1);
5908
5909	eventfd_ctx_put(event->eventfd);
5910	kfree(event);
5911	css_put(&memcg->css);
5912}
5913
5914/*
5915 * Gets called on POLLHUP on eventfd when user closes it.
5916 *
5917 * Called with wqh->lock held and interrupts disabled.
5918 */
5919static int memcg_event_wake(wait_queue_t *wait, unsigned mode,
5920			    int sync, void *key)
5921{
5922	struct mem_cgroup_event *event =
5923		container_of(wait, struct mem_cgroup_event, wait);
5924	struct mem_cgroup *memcg = event->memcg;
5925	unsigned long flags = (unsigned long)key;
5926
5927	if (flags & POLLHUP) {
5928		/*
5929		 * If the event has been detached at cgroup removal, we
5930		 * can simply return knowing the other side will cleanup
5931		 * for us.
5932		 *
5933		 * We can't race against event freeing since the other
5934		 * side will require wqh->lock via remove_wait_queue(),
5935		 * which we hold.
5936		 */
5937		spin_lock(&memcg->event_list_lock);
5938		if (!list_empty(&event->list)) {
5939			list_del_init(&event->list);
5940			/*
5941			 * We are in atomic context, but cgroup_event_remove()
5942			 * may sleep, so we have to call it in workqueue.
5943			 */
5944			schedule_work(&event->remove);
5945		}
5946		spin_unlock(&memcg->event_list_lock);
5947	}
5948
5949	return 0;
5950}
5951
5952static void memcg_event_ptable_queue_proc(struct file *file,
5953		wait_queue_head_t *wqh, poll_table *pt)
5954{
5955	struct mem_cgroup_event *event =
5956		container_of(pt, struct mem_cgroup_event, pt);
5957
5958	event->wqh = wqh;
5959	add_wait_queue(wqh, &event->wait);
5960}
5961
5962/*
5963 * DO NOT USE IN NEW FILES.
5964 *
5965 * Parse input and register new cgroup event handler.
5966 *
5967 * Input must be in format '<event_fd> <control_fd> <args>'.
5968 * Interpretation of args is defined by control file implementation.
5969 */
5970static int memcg_write_event_control(struct cgroup_subsys_state *css,
5971				     struct cftype *cft, char *buffer)
5972{
 
5973	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5974	struct mem_cgroup_event *event;
5975	struct cgroup_subsys_state *cfile_css;
5976	unsigned int efd, cfd;
5977	struct fd efile;
5978	struct fd cfile;
 
5979	const char *name;
5980	char *endp;
5981	int ret;
5982
5983	efd = simple_strtoul(buffer, &endp, 10);
 
 
 
 
 
5984	if (*endp != ' ')
5985		return -EINVAL;
5986	buffer = endp + 1;
5987
5988	cfd = simple_strtoul(buffer, &endp, 10);
5989	if ((*endp != ' ') && (*endp != '\0'))
5990		return -EINVAL;
5991	buffer = endp + 1;
5992
5993	event = kzalloc(sizeof(*event), GFP_KERNEL);
5994	if (!event)
5995		return -ENOMEM;
5996
5997	event->memcg = memcg;
5998	INIT_LIST_HEAD(&event->list);
5999	init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc);
6000	init_waitqueue_func_entry(&event->wait, memcg_event_wake);
6001	INIT_WORK(&event->remove, memcg_event_remove);
6002
6003	efile = fdget(efd);
6004	if (!efile.file) {
6005		ret = -EBADF;
6006		goto out_kfree;
6007	}
6008
6009	event->eventfd = eventfd_ctx_fileget(efile.file);
6010	if (IS_ERR(event->eventfd)) {
6011		ret = PTR_ERR(event->eventfd);
6012		goto out_put_efile;
6013	}
6014
6015	cfile = fdget(cfd);
6016	if (!cfile.file) {
6017		ret = -EBADF;
6018		goto out_put_eventfd;
6019	}
6020
6021	/* the process need read permission on control file */
6022	/* AV: shouldn't we check that it's been opened for read instead? */
6023	ret = inode_permission(file_inode(cfile.file), MAY_READ);
6024	if (ret < 0)
6025		goto out_put_cfile;
6026
6027	/*
 
 
 
 
 
 
 
 
 
 
6028	 * Determine the event callbacks and set them in @event.  This used
6029	 * to be done via struct cftype but cgroup core no longer knows
6030	 * about these events.  The following is crude but the whole thing
6031	 * is for compatibility anyway.
6032	 *
6033	 * DO NOT ADD NEW FILES.
6034	 */
6035	name = cfile.file->f_dentry->d_name.name;
6036
6037	if (!strcmp(name, "memory.usage_in_bytes")) {
6038		event->register_event = mem_cgroup_usage_register_event;
6039		event->unregister_event = mem_cgroup_usage_unregister_event;
6040	} else if (!strcmp(name, "memory.oom_control")) {
6041		event->register_event = mem_cgroup_oom_register_event;
6042		event->unregister_event = mem_cgroup_oom_unregister_event;
6043	} else if (!strcmp(name, "memory.pressure_level")) {
6044		event->register_event = vmpressure_register_event;
6045		event->unregister_event = vmpressure_unregister_event;
6046	} else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
6047		event->register_event = memsw_cgroup_usage_register_event;
6048		event->unregister_event = memsw_cgroup_usage_unregister_event;
6049	} else {
6050		ret = -EINVAL;
6051		goto out_put_cfile;
6052	}
6053
6054	/*
6055	 * Verify @cfile should belong to @css.  Also, remaining events are
6056	 * automatically removed on cgroup destruction but the removal is
6057	 * asynchronous, so take an extra ref on @css.
6058	 */
6059	cfile_css = css_tryget_from_dir(cfile.file->f_dentry->d_parent,
6060					&memory_cgrp_subsys);
6061	ret = -EINVAL;
6062	if (IS_ERR(cfile_css))
6063		goto out_put_cfile;
6064	if (cfile_css != css) {
6065		css_put(cfile_css);
6066		goto out_put_cfile;
6067	}
6068
6069	ret = event->register_event(memcg, event->eventfd, buffer);
6070	if (ret)
6071		goto out_put_css;
6072
6073	efile.file->f_op->poll(efile.file, &event->pt);
6074
6075	spin_lock(&memcg->event_list_lock);
6076	list_add(&event->list, &memcg->event_list);
6077	spin_unlock(&memcg->event_list_lock);
6078
6079	fdput(cfile);
6080	fdput(efile);
6081
6082	return 0;
6083
6084out_put_css:
6085	css_put(css);
6086out_put_cfile:
6087	fdput(cfile);
6088out_put_eventfd:
6089	eventfd_ctx_put(event->eventfd);
6090out_put_efile:
6091	fdput(efile);
6092out_kfree:
6093	kfree(event);
6094
6095	return ret;
6096}
6097
6098static struct cftype mem_cgroup_files[] = {
 
 
 
 
 
 
 
 
 
 
 
 
 
6099	{
6100		.name = "usage_in_bytes",
6101		.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
6102		.read_u64 = mem_cgroup_read_u64,
6103	},
6104	{
6105		.name = "max_usage_in_bytes",
6106		.private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
6107		.trigger = mem_cgroup_reset,
6108		.read_u64 = mem_cgroup_read_u64,
6109	},
6110	{
6111		.name = "limit_in_bytes",
6112		.private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
6113		.write_string = mem_cgroup_write,
6114		.read_u64 = mem_cgroup_read_u64,
6115	},
6116	{
6117		.name = "soft_limit_in_bytes",
6118		.private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
6119		.write_string = mem_cgroup_write,
6120		.read_u64 = mem_cgroup_read_u64,
6121	},
6122	{
6123		.name = "failcnt",
6124		.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
6125		.trigger = mem_cgroup_reset,
6126		.read_u64 = mem_cgroup_read_u64,
6127	},
6128	{
6129		.name = "stat",
6130		.seq_show = memcg_stat_show,
6131	},
6132	{
6133		.name = "force_empty",
6134		.trigger = mem_cgroup_force_empty_write,
6135	},
6136	{
6137		.name = "use_hierarchy",
6138		.flags = CFTYPE_INSANE,
6139		.write_u64 = mem_cgroup_hierarchy_write,
6140		.read_u64 = mem_cgroup_hierarchy_read,
6141	},
6142	{
6143		.name = "cgroup.event_control",		/* XXX: for compat */
6144		.write_string = memcg_write_event_control,
6145		.flags = CFTYPE_NO_PREFIX,
6146		.mode = S_IWUGO,
6147	},
6148	{
6149		.name = "swappiness",
6150		.read_u64 = mem_cgroup_swappiness_read,
6151		.write_u64 = mem_cgroup_swappiness_write,
6152	},
6153	{
6154		.name = "move_charge_at_immigrate",
6155		.read_u64 = mem_cgroup_move_charge_read,
6156		.write_u64 = mem_cgroup_move_charge_write,
6157	},
6158	{
6159		.name = "oom_control",
6160		.seq_show = mem_cgroup_oom_control_read,
6161		.write_u64 = mem_cgroup_oom_control_write,
6162		.private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
6163	},
6164	{
6165		.name = "pressure_level",
 
6166	},
6167#ifdef CONFIG_NUMA
6168	{
6169		.name = "numa_stat",
6170		.seq_show = memcg_numa_stat_show,
6171	},
6172#endif
6173#ifdef CONFIG_MEMCG_KMEM
6174	{
6175		.name = "kmem.limit_in_bytes",
6176		.private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
6177		.write_string = mem_cgroup_write,
6178		.read_u64 = mem_cgroup_read_u64,
6179	},
6180	{
6181		.name = "kmem.usage_in_bytes",
6182		.private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
6183		.read_u64 = mem_cgroup_read_u64,
6184	},
6185	{
6186		.name = "kmem.failcnt",
6187		.private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
6188		.trigger = mem_cgroup_reset,
6189		.read_u64 = mem_cgroup_read_u64,
6190	},
6191	{
6192		.name = "kmem.max_usage_in_bytes",
6193		.private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
6194		.trigger = mem_cgroup_reset,
6195		.read_u64 = mem_cgroup_read_u64,
6196	},
6197#ifdef CONFIG_SLABINFO
6198	{
6199		.name = "kmem.slabinfo",
6200		.seq_show = mem_cgroup_slabinfo_read,
6201	},
6202#endif
6203#endif
6204	{ },	/* terminate */
6205};
6206
6207#ifdef CONFIG_MEMCG_SWAP
6208static struct cftype memsw_cgroup_files[] = {
6209	{
6210		.name = "memsw.usage_in_bytes",
6211		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
 
6212		.read_u64 = mem_cgroup_read_u64,
6213	},
6214	{
6215		.name = "memsw.max_usage_in_bytes",
6216		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
6217		.trigger = mem_cgroup_reset,
6218		.read_u64 = mem_cgroup_read_u64,
6219	},
6220	{
6221		.name = "memsw.limit_in_bytes",
6222		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
6223		.write_string = mem_cgroup_write,
6224		.read_u64 = mem_cgroup_read_u64,
6225	},
6226	{
6227		.name = "memsw.failcnt",
6228		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
6229		.trigger = mem_cgroup_reset,
6230		.read_u64 = mem_cgroup_read_u64,
6231	},
6232	{ },	/* terminate */
6233};
6234#endif
6235static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6236{
6237	struct mem_cgroup_per_node *pn;
6238	struct mem_cgroup_per_zone *mz;
6239	int zone, tmp = node;
6240	/*
6241	 * This routine is called against possible nodes.
6242	 * But it's BUG to call kmalloc() against offline node.
6243	 *
6244	 * TODO: this routine can waste much memory for nodes which will
6245	 *       never be onlined. It's better to use memory hotplug callback
6246	 *       function.
6247	 */
6248	if (!node_state(node, N_NORMAL_MEMORY))
6249		tmp = -1;
6250	pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
6251	if (!pn)
6252		return 1;
6253
6254	for (zone = 0; zone < MAX_NR_ZONES; zone++) {
6255		mz = &pn->zoneinfo[zone];
6256		lruvec_init(&mz->lruvec);
6257		mz->usage_in_excess = 0;
6258		mz->on_tree = false;
6259		mz->memcg = memcg;
6260	}
6261	memcg->nodeinfo[node] = pn;
6262	return 0;
6263}
6264
6265static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
 
 
 
 
 
 
 
 
 
 
 
6266{
6267	kfree(memcg->nodeinfo[node]);
 
6268}
6269
6270static struct mem_cgroup *mem_cgroup_alloc(void)
 
6271{
 
 
6272	struct mem_cgroup *memcg;
6273	size_t size;
6274
6275	size = sizeof(struct mem_cgroup);
6276	size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
 
 
 
 
 
 
 
6277
6278	memcg = kzalloc(size, GFP_KERNEL);
6279	if (!memcg)
6280		return NULL;
6281
6282	memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
6283	if (!memcg->stat)
6284		goto out_free;
6285	spin_lock_init(&memcg->pcp_counter_lock);
6286	return memcg;
6287
6288out_free:
6289	kfree(memcg);
6290	return NULL;
6291}
 
6292
6293/*
6294 * At destroying mem_cgroup, references from swap_cgroup can remain.
6295 * (scanning all at force_empty is too costly...)
6296 *
6297 * Instead of clearing all references at force_empty, we remember
6298 * the number of reference from swap_cgroup and free mem_cgroup when
6299 * it goes down to 0.
6300 *
6301 * Removal of cgroup itself succeeds regardless of refs from swap.
6302 */
6303
6304static void __mem_cgroup_free(struct mem_cgroup *memcg)
6305{
6306	int node;
6307
6308	mem_cgroup_remove_from_trees(memcg);
 
 
6309
6310	for_each_node(node)
6311		free_mem_cgroup_per_zone_info(memcg, node);
 
 
 
 
6312
6313	free_percpu(memcg->stat);
 
6314
6315	/*
6316	 * We need to make sure that (at least for now), the jump label
6317	 * destruction code runs outside of the cgroup lock. This is because
6318	 * get_online_cpus(), which is called from the static_branch update,
6319	 * can't be called inside the cgroup_lock. cpusets are the ones
6320	 * enforcing this dependency, so if they ever change, we might as well.
6321	 *
6322	 * schedule_work() will guarantee this happens. Be careful if you need
6323	 * to move this code around, and make sure it is outside
6324	 * the cgroup_lock.
6325	 */
6326	disarm_static_keys(memcg);
6327	kfree(memcg);
6328}
6329
6330/*
6331 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
6332 */
6333struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
6334{
6335	if (!memcg->res.parent)
6336		return NULL;
6337	return mem_cgroup_from_res_counter(memcg->res.parent, res);
 
 
 
 
6338}
6339EXPORT_SYMBOL(parent_mem_cgroup);
6340
6341static void __init mem_cgroup_soft_limit_tree_init(void)
6342{
6343	struct mem_cgroup_tree_per_node *rtpn;
6344	struct mem_cgroup_tree_per_zone *rtpz;
6345	int tmp, node, zone;
6346
6347	for_each_node(node) {
6348		tmp = node;
6349		if (!node_state(node, N_NORMAL_MEMORY))
6350			tmp = -1;
6351		rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
6352		BUG_ON(!rtpn);
6353
6354		soft_limit_tree.rb_tree_per_node[node] = rtpn;
 
 
 
 
 
6355
6356		for (zone = 0; zone < MAX_NR_ZONES; zone++) {
6357			rtpz = &rtpn->rb_tree_per_zone[zone];
6358			rtpz->rb_root = RB_ROOT;
6359			spin_lock_init(&rtpz->lock);
6360		}
6361	}
6362}
6363
6364static struct cgroup_subsys_state * __ref
6365mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
6366{
 
6367	struct mem_cgroup *memcg;
 
 
6368	long error = -ENOMEM;
6369	int node;
6370
6371	memcg = mem_cgroup_alloc();
6372	if (!memcg)
6373		return ERR_PTR(error);
6374
6375	for_each_node(node)
6376		if (alloc_mem_cgroup_per_zone_info(memcg, node))
6377			goto free_out;
 
 
 
6378
6379	/* root ? */
6380	if (parent_css == NULL) {
6381		root_mem_cgroup = memcg;
6382		res_counter_init(&memcg->res, NULL);
6383		res_counter_init(&memcg->memsw, NULL);
6384		res_counter_init(&memcg->kmem, NULL);
 
 
 
 
 
 
 
 
 
6385	}
6386
6387	memcg->last_scanned_node = MAX_NUMNODES;
 
 
 
 
 
 
 
6388	INIT_LIST_HEAD(&memcg->oom_notify);
6389	memcg->move_charge_at_immigrate = 0;
6390	mutex_init(&memcg->thresholds_lock);
6391	spin_lock_init(&memcg->move_lock);
6392	vmpressure_init(&memcg->vmpressure);
6393	INIT_LIST_HEAD(&memcg->event_list);
6394	spin_lock_init(&memcg->event_list_lock);
6395
6396	return &memcg->css;
6397
6398free_out:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6399	__mem_cgroup_free(memcg);
6400	return ERR_PTR(error);
6401}
6402
6403static int
6404mem_cgroup_css_online(struct cgroup_subsys_state *css)
6405{
6406	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6407	struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(css));
6408
6409	if (css->cgroup->id > MEM_CGROUP_ID_MAX)
6410		return -ENOSPC;
6411
6412	if (!parent)
6413		return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6414
6415	mutex_lock(&memcg_create_mutex);
 
 
6416
6417	memcg->use_hierarchy = parent->use_hierarchy;
6418	memcg->oom_kill_disable = parent->oom_kill_disable;
6419	memcg->swappiness = mem_cgroup_swappiness(parent);
6420
6421	if (parent->use_hierarchy) {
6422		res_counter_init(&memcg->res, &parent->res);
6423		res_counter_init(&memcg->memsw, &parent->memsw);
6424		res_counter_init(&memcg->kmem, &parent->kmem);
6425
6426		/*
6427		 * No need to take a reference to the parent because cgroup
6428		 * core guarantees its existence.
6429		 */
6430	} else {
6431		res_counter_init(&memcg->res, NULL);
6432		res_counter_init(&memcg->memsw, NULL);
6433		res_counter_init(&memcg->kmem, NULL);
6434		/*
6435		 * Deeper hierachy with use_hierarchy == false doesn't make
6436		 * much sense so let cgroup subsystem know about this
6437		 * unfortunate state in our controller.
6438		 */
6439		if (parent != root_mem_cgroup)
6440			memory_cgrp_subsys.broken_hierarchy = true;
6441	}
6442	mutex_unlock(&memcg_create_mutex);
6443
6444	return memcg_init_kmem(memcg, &memory_cgrp_subsys);
6445}
6446
6447/*
6448 * Announce all parents that a group from their hierarchy is gone.
6449 */
6450static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup *memcg)
6451{
6452	struct mem_cgroup *parent = memcg;
6453
6454	while ((parent = parent_mem_cgroup(parent)))
6455		mem_cgroup_iter_invalidate(parent);
6456
6457	/*
6458	 * if the root memcg is not hierarchical we have to check it
6459	 * explicitely.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6460	 */
6461	if (!root_mem_cgroup->use_hierarchy)
6462		mem_cgroup_iter_invalidate(root_mem_cgroup);
 
 
 
 
 
 
6463}
6464
6465static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
6466{
6467	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6468	struct mem_cgroup_event *event, *tmp;
6469	struct cgroup_subsys_state *iter;
6470
6471	/*
6472	 * Unregister events and notify userspace.
6473	 * Notify userspace about cgroup removing only after rmdir of cgroup
6474	 * directory to avoid race between userspace and kernelspace.
6475	 */
6476	spin_lock(&memcg->event_list_lock);
6477	list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
6478		list_del_init(&event->list);
6479		schedule_work(&event->remove);
6480	}
6481	spin_unlock(&memcg->event_list_lock);
6482
6483	kmem_cgroup_css_offline(memcg);
 
6484
6485	mem_cgroup_invalidate_reclaim_iterators(memcg);
6486
6487	/*
6488	 * This requires that offlining is serialized.  Right now that is
6489	 * guaranteed because css_killed_work_fn() holds the cgroup_mutex.
6490	 */
6491	css_for_each_descendant_post(iter, css)
6492		mem_cgroup_reparent_charges(mem_cgroup_from_css(iter));
6493
6494	mem_cgroup_destroy_all_caches(memcg);
6495	vmpressure_cleanup(&memcg->vmpressure);
 
 
 
 
 
 
 
 
 
6496}
6497
6498static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
6499{
6500	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6501	/*
6502	 * XXX: css_offline() would be where we should reparent all
6503	 * memory to prepare the cgroup for destruction.  However,
6504	 * memcg does not do css_tryget() and res_counter charging
6505	 * under the same RCU lock region, which means that charging
6506	 * could race with offlining.  Offlining only happens to
6507	 * cgroups with no tasks in them but charges can show up
6508	 * without any tasks from the swapin path when the target
6509	 * memcg is looked up from the swapout record and not from the
6510	 * current task as it usually is.  A race like this can leak
6511	 * charges and put pages with stale cgroup pointers into
6512	 * circulation:
6513	 *
6514	 * #0                        #1
6515	 *                           lookup_swap_cgroup_id()
6516	 *                           rcu_read_lock()
6517	 *                           mem_cgroup_lookup()
6518	 *                           css_tryget()
6519	 *                           rcu_read_unlock()
6520	 * disable css_tryget()
6521	 * call_rcu()
6522	 *   offline_css()
6523	 *     reparent_charges()
6524	 *                           res_counter_charge()
6525	 *                           css_put()
6526	 *                             css_free()
6527	 *                           pc->mem_cgroup = dead memcg
6528	 *                           add page to lru
6529	 *
6530	 * The bulk of the charges are still moved in offline_css() to
6531	 * avoid pinning a lot of pages in case a long-term reference
6532	 * like a swapout record is deferring the css_free() to long
6533	 * after offlining.  But this makes sure we catch any charges
6534	 * made after offlining:
6535	 */
6536	mem_cgroup_reparent_charges(memcg);
6537
6538	memcg_destroy_kmem(memcg);
6539	__mem_cgroup_free(memcg);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6540}
6541
6542#ifdef CONFIG_MMU
6543/* Handlers for move charge at task migration. */
6544#define PRECHARGE_COUNT_AT_ONCE	256
6545static int mem_cgroup_do_precharge(unsigned long count)
 
 
 
 
 
 
 
 
 
 
6546{
6547	int ret = 0;
6548	int batch_count = PRECHARGE_COUNT_AT_ONCE;
6549	struct mem_cgroup *memcg = mc.to;
6550
6551	if (mem_cgroup_is_root(memcg)) {
6552		mc.precharge += count;
6553		/* we don't need css_get for root */
6554		return ret;
6555	}
6556	/* try to charge at once */
6557	if (count > 1) {
6558		struct res_counter *dummy;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6559		/*
6560		 * "memcg" cannot be under rmdir() because we've already checked
6561		 * by cgroup_lock_live_cgroup() that it is not removed and we
6562		 * are still under the same cgroup_mutex. So we can postpone
6563		 * css_get().
6564		 */
6565		if (res_counter_charge(&memcg->res, PAGE_SIZE * count, &dummy))
6566			goto one_by_one;
6567		if (do_swap_account && res_counter_charge(&memcg->memsw,
6568						PAGE_SIZE * count, &dummy)) {
6569			res_counter_uncharge(&memcg->res, PAGE_SIZE * count);
6570			goto one_by_one;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6571		}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6572		mc.precharge += count;
6573		return ret;
6574	}
6575one_by_one:
6576	/* fall back to one by one charge */
6577	while (count--) {
6578		if (signal_pending(current)) {
6579			ret = -EINTR;
6580			break;
6581		}
6582		if (!batch_count--) {
6583			batch_count = PRECHARGE_COUNT_AT_ONCE;
6584			cond_resched();
6585		}
6586		ret = mem_cgroup_try_charge(memcg, GFP_KERNEL, 1, false);
6587		if (ret)
6588			/* mem_cgroup_clear_mc() will do uncharge later */
6589			return ret;
6590		mc.precharge++;
 
6591	}
6592	return ret;
6593}
6594
6595/**
6596 * get_mctgt_type - get target type of moving charge
6597 * @vma: the vma the pte to be checked belongs
6598 * @addr: the address corresponding to the pte to be checked
6599 * @ptent: the pte to be checked
6600 * @target: the pointer the target page or swap ent will be stored(can be NULL)
6601 *
6602 * Returns
6603 *   0(MC_TARGET_NONE): if the pte is not a target for move charge.
6604 *   1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
6605 *     move charge. if @target is not NULL, the page is stored in target->page
6606 *     with extra refcnt got(Callers should handle it).
6607 *   2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
6608 *     target for charge migration. if @target is not NULL, the entry is stored
6609 *     in target->ent.
6610 *
6611 * Called with pte lock held.
6612 */
6613union mc_target {
6614	struct page	*page;
6615	swp_entry_t	ent;
6616};
6617
6618enum mc_target_type {
6619	MC_TARGET_NONE = 0,
6620	MC_TARGET_PAGE,
6621	MC_TARGET_SWAP,
 
6622};
6623
6624static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
6625						unsigned long addr, pte_t ptent)
6626{
6627	struct page *page = vm_normal_page(vma, addr, ptent);
6628
6629	if (!page || !page_mapped(page))
6630		return NULL;
6631	if (PageAnon(page)) {
6632		/* we don't move shared anon */
6633		if (!move_anon())
6634			return NULL;
6635	} else if (!move_file())
6636		/* we ignore mapcount for file pages */
6637		return NULL;
6638	if (!get_page_unless_zero(page))
6639		return NULL;
6640
6641	return page;
6642}
6643
6644#ifdef CONFIG_SWAP
6645static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
6646			unsigned long addr, pte_t ptent, swp_entry_t *entry)
6647{
6648	struct page *page = NULL;
6649	swp_entry_t ent = pte_to_swp_entry(ptent);
6650
6651	if (!move_anon() || non_swap_entry(ent))
6652		return NULL;
 
6653	/*
6654	 * Because lookup_swap_cache() updates some statistics counter,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6655	 * we call find_get_page() with swapper_space directly.
6656	 */
6657	page = find_get_page(swap_address_space(ent), ent.val);
6658	if (do_swap_account)
6659		entry->val = ent.val;
6660
6661	return page;
6662}
6663#else
6664static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
6665			unsigned long addr, pte_t ptent, swp_entry_t *entry)
6666{
6667	return NULL;
6668}
6669#endif
6670
6671static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
6672			unsigned long addr, pte_t ptent, swp_entry_t *entry)
6673{
6674	struct page *page = NULL;
6675	struct address_space *mapping;
6676	pgoff_t pgoff;
6677
6678	if (!vma->vm_file) /* anonymous vma */
6679		return NULL;
6680	if (!move_file())
6681		return NULL;
6682
6683	mapping = vma->vm_file->f_mapping;
6684	if (pte_none(ptent))
6685		pgoff = linear_page_index(vma, addr);
6686	else /* pte_file(ptent) is true */
6687		pgoff = pte_to_pgoff(ptent);
6688
6689	/* page is moved even if it's not RSS of this task(page-faulted). */
6690#ifdef CONFIG_SWAP
6691	/* shmem/tmpfs may report page out on swap: account for that too. */
6692	if (shmem_mapping(mapping)) {
6693		page = find_get_entry(mapping, pgoff);
6694		if (radix_tree_exceptional_entry(page)) {
6695			swp_entry_t swp = radix_to_swp_entry(page);
6696			if (do_swap_account)
6697				*entry = swp;
6698			page = find_get_page(swap_address_space(swp), swp.val);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6699		}
6700	} else
6701		page = find_get_page(mapping, pgoff);
6702#else
6703	page = find_get_page(mapping, pgoff);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6704#endif
6705	return page;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6706}
6707
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6708static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
6709		unsigned long addr, pte_t ptent, union mc_target *target)
6710{
6711	struct page *page = NULL;
6712	struct page_cgroup *pc;
6713	enum mc_target_type ret = MC_TARGET_NONE;
6714	swp_entry_t ent = { .val = 0 };
6715
6716	if (pte_present(ptent))
6717		page = mc_handle_present_pte(vma, addr, ptent);
 
 
 
 
 
 
6718	else if (is_swap_pte(ptent))
6719		page = mc_handle_swap_pte(vma, addr, ptent, &ent);
6720	else if (pte_none(ptent) || pte_file(ptent))
6721		page = mc_handle_file_pte(vma, addr, ptent, &ent);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6722
6723	if (!page && !ent.val)
6724		return ret;
6725	if (page) {
6726		pc = lookup_page_cgroup(page);
6727		/*
6728		 * Do only loose check w/o page_cgroup lock.
6729		 * mem_cgroup_move_account() checks the pc is valid or not under
6730		 * the lock.
6731		 */
6732		if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
6733			ret = MC_TARGET_PAGE;
 
 
 
 
 
 
 
6734			if (target)
6735				target->page = page;
 
6736		}
6737		if (!ret || !target)
6738			put_page(page);
6739	}
6740	/* There is a swap entry and a page doesn't exist or isn't charged */
6741	if (ent.val && !ret &&
 
 
 
6742	    mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) {
6743		ret = MC_TARGET_SWAP;
6744		if (target)
6745			target->ent = ent;
6746	}
6747	return ret;
6748}
6749
6750#ifdef CONFIG_TRANSPARENT_HUGEPAGE
6751/*
6752 * We don't consider swapping or file mapped pages because THP does not
6753 * support them for now.
6754 * Caller should make sure that pmd_trans_huge(pmd) is true.
6755 */
6756static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
6757		unsigned long addr, pmd_t pmd, union mc_target *target)
6758{
6759	struct page *page = NULL;
6760	struct page_cgroup *pc;
6761	enum mc_target_type ret = MC_TARGET_NONE;
6762
 
 
 
 
 
6763	page = pmd_page(pmd);
6764	VM_BUG_ON_PAGE(!page || !PageHead(page), page);
6765	if (!move_anon())
 
6766		return ret;
6767	pc = lookup_page_cgroup(page);
6768	if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
6769		ret = MC_TARGET_PAGE;
6770		if (target) {
6771			get_page(page);
6772			target->page = page;
 
 
 
 
6773		}
6774	}
6775	return ret;
6776}
6777#else
6778static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
6779		unsigned long addr, pmd_t pmd, union mc_target *target)
6780{
6781	return MC_TARGET_NONE;
6782}
6783#endif
6784
6785static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
6786					unsigned long addr, unsigned long end,
6787					struct mm_walk *walk)
6788{
6789	struct vm_area_struct *vma = walk->private;
6790	pte_t *pte;
6791	spinlock_t *ptl;
6792
6793	if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
 
 
 
 
 
 
6794		if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
6795			mc.precharge += HPAGE_PMD_NR;
6796		spin_unlock(ptl);
6797		return 0;
6798	}
6799
6800	if (pmd_trans_unstable(pmd))
6801		return 0;
6802	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
 
 
6803	for (; addr != end; pte++, addr += PAGE_SIZE)
6804		if (get_mctgt_type(vma, addr, *pte, NULL))
6805			mc.precharge++;	/* increment precharge temporarily */
6806	pte_unmap_unlock(pte - 1, ptl);
6807	cond_resched();
6808
6809	return 0;
6810}
6811
 
 
 
 
 
6812static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
6813{
6814	unsigned long precharge;
6815	struct vm_area_struct *vma;
6816
6817	down_read(&mm->mmap_sem);
6818	for (vma = mm->mmap; vma; vma = vma->vm_next) {
6819		struct mm_walk mem_cgroup_count_precharge_walk = {
6820			.pmd_entry = mem_cgroup_count_precharge_pte_range,
6821			.mm = mm,
6822			.private = vma,
6823		};
6824		if (is_vm_hugetlb_page(vma))
6825			continue;
6826		walk_page_range(vma->vm_start, vma->vm_end,
6827					&mem_cgroup_count_precharge_walk);
6828	}
6829	up_read(&mm->mmap_sem);
6830
6831	precharge = mc.precharge;
6832	mc.precharge = 0;
6833
6834	return precharge;
6835}
6836
6837static int mem_cgroup_precharge_mc(struct mm_struct *mm)
6838{
6839	unsigned long precharge = mem_cgroup_count_precharge(mm);
6840
6841	VM_BUG_ON(mc.moving_task);
6842	mc.moving_task = current;
6843	return mem_cgroup_do_precharge(precharge);
6844}
6845
6846/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
6847static void __mem_cgroup_clear_mc(void)
6848{
6849	struct mem_cgroup *from = mc.from;
6850	struct mem_cgroup *to = mc.to;
6851	int i;
6852
6853	/* we must uncharge all the leftover precharges from mc.to */
6854	if (mc.precharge) {
6855		__mem_cgroup_cancel_charge(mc.to, mc.precharge);
6856		mc.precharge = 0;
6857	}
6858	/*
6859	 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
6860	 * we must uncharge here.
6861	 */
6862	if (mc.moved_charge) {
6863		__mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
6864		mc.moved_charge = 0;
6865	}
6866	/* we must fixup refcnts and charges */
6867	if (mc.moved_swap) {
6868		/* uncharge swap account from the old cgroup */
6869		if (!mem_cgroup_is_root(mc.from))
6870			res_counter_uncharge(&mc.from->memsw,
6871						PAGE_SIZE * mc.moved_swap);
6872
6873		for (i = 0; i < mc.moved_swap; i++)
6874			css_put(&mc.from->css);
 
 
 
 
 
 
6875
6876		if (!mem_cgroup_is_root(mc.to)) {
6877			/*
6878			 * we charged both to->res and to->memsw, so we should
6879			 * uncharge to->res.
6880			 */
6881			res_counter_uncharge(&mc.to->res,
6882						PAGE_SIZE * mc.moved_swap);
6883		}
6884		/* we've already done css_get(mc.to) */
6885		mc.moved_swap = 0;
6886	}
6887	memcg_oom_recover(from);
6888	memcg_oom_recover(to);
6889	wake_up_all(&mc.waitq);
6890}
6891
6892static void mem_cgroup_clear_mc(void)
6893{
6894	struct mem_cgroup *from = mc.from;
6895
6896	/*
6897	 * we must clear moving_task before waking up waiters at the end of
6898	 * task migration.
6899	 */
6900	mc.moving_task = NULL;
6901	__mem_cgroup_clear_mc();
6902	spin_lock(&mc.lock);
6903	mc.from = NULL;
6904	mc.to = NULL;
 
6905	spin_unlock(&mc.lock);
6906	mem_cgroup_end_move(from);
 
6907}
6908
6909static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
6910				 struct cgroup_taskset *tset)
6911{
6912	struct task_struct *p = cgroup_taskset_first(tset);
 
 
 
 
 
6913	int ret = 0;
6914	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6915	unsigned long move_charge_at_immigrate;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6916
6917	/*
6918	 * We are now commited to this value whatever it is. Changes in this
6919	 * tunable will only affect upcoming migrations, not the current one.
6920	 * So we need to save it, and keep it going.
6921	 */
6922	move_charge_at_immigrate  = memcg->move_charge_at_immigrate;
6923	if (move_charge_at_immigrate) {
6924		struct mm_struct *mm;
6925		struct mem_cgroup *from = mem_cgroup_from_task(p);
6926
6927		VM_BUG_ON(from == memcg);
6928
6929		mm = get_task_mm(p);
6930		if (!mm)
6931			return 0;
6932		/* We move charges only when we move a owner of the mm */
6933		if (mm->owner == p) {
6934			VM_BUG_ON(mc.from);
6935			VM_BUG_ON(mc.to);
6936			VM_BUG_ON(mc.precharge);
6937			VM_BUG_ON(mc.moved_charge);
6938			VM_BUG_ON(mc.moved_swap);
6939			mem_cgroup_start_move(from);
6940			spin_lock(&mc.lock);
6941			mc.from = from;
6942			mc.to = memcg;
6943			mc.immigrate_flags = move_charge_at_immigrate;
6944			spin_unlock(&mc.lock);
6945			/* We set mc.moving_task later */
6946
6947			ret = mem_cgroup_precharge_mc(mm);
6948			if (ret)
6949				mem_cgroup_clear_mc();
6950		}
 
 
 
6951		mmput(mm);
6952	}
6953	return ret;
6954}
6955
6956static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
6957				     struct cgroup_taskset *tset)
6958{
6959	mem_cgroup_clear_mc();
 
6960}
6961
6962static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
6963				unsigned long addr, unsigned long end,
6964				struct mm_walk *walk)
6965{
6966	int ret = 0;
6967	struct vm_area_struct *vma = walk->private;
6968	pte_t *pte;
6969	spinlock_t *ptl;
6970	enum mc_target_type target_type;
6971	union mc_target target;
6972	struct page *page;
6973	struct page_cgroup *pc;
6974
6975	/*
6976	 * We don't take compound_lock() here but no race with splitting thp
6977	 * happens because:
6978	 *  - if pmd_trans_huge_lock() returns 1, the relevant thp is not
6979	 *    under splitting, which means there's no concurrent thp split,
6980	 *  - if another thread runs into split_huge_page() just after we
6981	 *    entered this if-block, the thread must wait for page table lock
6982	 *    to be unlocked in __split_huge_page_splitting(), where the main
6983	 *    part of thp split is not executed yet.
6984	 */
6985	if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
6986		if (mc.precharge < HPAGE_PMD_NR) {
6987			spin_unlock(ptl);
6988			return 0;
6989		}
6990		target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
6991		if (target_type == MC_TARGET_PAGE) {
6992			page = target.page;
6993			if (!isolate_lru_page(page)) {
6994				pc = lookup_page_cgroup(page);
6995				if (!mem_cgroup_move_account(page, HPAGE_PMD_NR,
6996							pc, mc.from, mc.to)) {
6997					mc.precharge -= HPAGE_PMD_NR;
6998					mc.moved_charge += HPAGE_PMD_NR;
6999				}
7000				putback_lru_page(page);
 
 
 
 
 
 
 
 
 
7001			}
7002			put_page(page);
 
7003		}
7004		spin_unlock(ptl);
7005		return 0;
7006	}
7007
7008	if (pmd_trans_unstable(pmd))
7009		return 0;
7010retry:
7011	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
 
 
7012	for (; addr != end; addr += PAGE_SIZE) {
7013		pte_t ptent = *(pte++);
 
7014		swp_entry_t ent;
7015
7016		if (!mc.precharge)
7017			break;
7018
7019		switch (get_mctgt_type(vma, addr, ptent, &target)) {
 
 
 
7020		case MC_TARGET_PAGE:
7021			page = target.page;
7022			if (isolate_lru_page(page))
 
 
 
 
 
 
7023				goto put;
7024			pc = lookup_page_cgroup(page);
7025			if (!mem_cgroup_move_account(page, 1, pc,
7026						     mc.from, mc.to)) {
 
7027				mc.precharge--;
7028				/* we uncharge from mc.from later. */
7029				mc.moved_charge++;
7030			}
7031			putback_lru_page(page);
7032put:			/* get_mctgt_type() gets the page */
7033			put_page(page);
 
 
7034			break;
7035		case MC_TARGET_SWAP:
7036			ent = target.ent;
7037			if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
7038				mc.precharge--;
7039				/* we fixup refcnts and charges later. */
 
7040				mc.moved_swap++;
7041			}
7042			break;
7043		default:
7044			break;
7045		}
7046	}
7047	pte_unmap_unlock(pte - 1, ptl);
7048	cond_resched();
7049
7050	if (addr != end) {
7051		/*
7052		 * We have consumed all precharges we got in can_attach().
7053		 * We try charge one by one, but don't do any additional
7054		 * charges to mc.to if we have failed in charge once in attach()
7055		 * phase.
7056		 */
7057		ret = mem_cgroup_do_precharge(1);
7058		if (!ret)
7059			goto retry;
7060	}
7061
7062	return ret;
7063}
7064
7065static void mem_cgroup_move_charge(struct mm_struct *mm)
7066{
7067	struct vm_area_struct *vma;
 
7068
 
 
7069	lru_add_drain_all();
 
 
 
 
 
 
 
7070retry:
7071	if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
7072		/*
7073		 * Someone who are holding the mmap_sem might be waiting in
7074		 * waitq. So we cancel all extra charges, wake up all waiters,
7075		 * and retry. Because we cancel precharges, we might not be able
7076		 * to move enough charges, but moving charge is a best-effort
7077		 * feature anyway, so it wouldn't be a big problem.
7078		 */
7079		__mem_cgroup_clear_mc();
7080		cond_resched();
7081		goto retry;
7082	}
7083	for (vma = mm->mmap; vma; vma = vma->vm_next) {
7084		int ret;
7085		struct mm_walk mem_cgroup_move_charge_walk = {
7086			.pmd_entry = mem_cgroup_move_charge_pte_range,
7087			.mm = mm,
7088			.private = vma,
7089		};
7090		if (is_vm_hugetlb_page(vma))
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7091			continue;
7092		ret = walk_page_range(vma->vm_start, vma->vm_end,
7093						&mem_cgroup_move_charge_walk);
7094		if (ret)
7095			/*
7096			 * means we have consumed all precharges and failed in
7097			 * doing additional charge. Just abandon here.
7098			 */
7099			break;
7100	}
7101	up_read(&mm->mmap_sem);
 
 
 
 
 
 
 
 
7102}
7103
7104static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
7105				 struct cgroup_taskset *tset)
7106{
7107	struct task_struct *p = cgroup_taskset_first(tset);
7108	struct mm_struct *mm = get_task_mm(p);
 
 
 
7109
7110	if (mm) {
7111		if (mc.to)
7112			mem_cgroup_move_charge(mm);
7113		mmput(mm);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7114	}
7115	if (mc.to)
7116		mem_cgroup_clear_mc();
 
7117}
7118#else	/* !CONFIG_MMU */
7119static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
7120				 struct cgroup_taskset *tset)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7121{
 
 
 
7122	return 0;
7123}
7124static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
7125				     struct cgroup_taskset *tset)
7126{
 
 
 
 
7127}
7128static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
7129				 struct cgroup_taskset *tset)
7130{
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7131}
7132#endif
7133
7134/*
7135 * Cgroup retains root cgroups across [un]mount cycles making it necessary
7136 * to verify sane_behavior flag on each mount attempt.
7137 */
7138static void mem_cgroup_bind(struct cgroup_subsys_state *root_css)
7139{
7140	/*
7141	 * use_hierarchy is forced with sane_behavior.  cgroup core
7142	 * guarantees that @root doesn't have any children, so turning it
7143	 * on for the root memcg is enough.
7144	 */
7145	if (cgroup_sane_behavior(root_css->cgroup))
7146		mem_cgroup_from_css(root_css)->use_hierarchy = true;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7147}
7148
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7149struct cgroup_subsys memory_cgrp_subsys = {
7150	.css_alloc = mem_cgroup_css_alloc,
7151	.css_online = mem_cgroup_css_online,
7152	.css_offline = mem_cgroup_css_offline,
 
7153	.css_free = mem_cgroup_css_free,
 
 
7154	.can_attach = mem_cgroup_can_attach,
 
 
 
7155	.cancel_attach = mem_cgroup_cancel_attach,
7156	.attach = mem_cgroup_move_task,
7157	.bind = mem_cgroup_bind,
7158	.base_cftypes = mem_cgroup_files,
 
 
 
 
7159	.early_init = 0,
7160};
7161
7162#ifdef CONFIG_MEMCG_SWAP
7163static int __init enable_swap_account(char *s)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7164{
7165	if (!strcmp(s, "1"))
7166		really_do_swap_account = 1;
7167	else if (!strcmp(s, "0"))
7168		really_do_swap_account = 0;
7169	return 1;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7170}
7171__setup("swapaccount=", enable_swap_account);
7172
7173static void __init memsw_file_init(void)
7174{
7175	WARN_ON(cgroup_add_cftypes(&memory_cgrp_subsys, memsw_cgroup_files));
 
 
 
 
 
 
 
7176}
7177
7178static void __init enable_swap_cgroup(void)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7179{
7180	if (!mem_cgroup_disabled() && really_do_swap_account) {
7181		do_swap_account = 1;
7182		memsw_file_init();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7183	}
7184}
7185
7186#else
7187static void __init enable_swap_cgroup(void)
 
 
 
 
 
 
 
7188{
 
7189}
7190#endif
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7191
7192/*
7193 * subsys_initcall() for memory controller.
7194 *
7195 * Some parts like hotcpu_notifier() have to be initialized from this context
7196 * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
7197 * everything that doesn't depend on a specific mem_cgroup structure should
7198 * be initialized from here.
7199 */
7200static int __init mem_cgroup_init(void)
7201{
7202	hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
7203	enable_swap_cgroup();
7204	mem_cgroup_soft_limit_tree_init();
7205	memcg_stock_init();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7206	return 0;
7207}
7208subsys_initcall(mem_cgroup_init);