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 * This program is free software; you can redistribute it and/or modify
  14 * it under the terms of the GNU General Public License as published by
  15 * the Free Software Foundation; either version 2 of the License, or
  16 * (at your option) any later version.
  17 *
  18 * This program is distributed in the hope that it will be useful,
  19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 * GNU General Public License for more details.
  22 */
  23
  24#include <linux/res_counter.h>
  25#include <linux/memcontrol.h>
  26#include <linux/cgroup.h>
  27#include <linux/mm.h>
  28#include <linux/hugetlb.h>
  29#include <linux/pagemap.h>
  30#include <linux/smp.h>
  31#include <linux/page-flags.h>
  32#include <linux/backing-dev.h>
  33#include <linux/bit_spinlock.h>
  34#include <linux/rcupdate.h>
  35#include <linux/limits.h>
 
  36#include <linux/mutex.h>
  37#include <linux/rbtree.h>
  38#include <linux/slab.h>
  39#include <linux/swap.h>
  40#include <linux/swapops.h>
  41#include <linux/spinlock.h>
  42#include <linux/eventfd.h>
 
  43#include <linux/sort.h>
  44#include <linux/fs.h>
  45#include <linux/seq_file.h>
  46#include <linux/vmalloc.h>
  47#include <linux/mm_inline.h>
  48#include <linux/page_cgroup.h>
  49#include <linux/cpu.h>
  50#include <linux/oom.h>
 
 
 
  51#include "internal.h"
 
 
 
  52
  53#include <asm/uaccess.h>
  54
  55#include <trace/events/vmscan.h>
  56
  57struct cgroup_subsys mem_cgroup_subsys __read_mostly;
  58#define MEM_CGROUP_RECLAIM_RETRIES	5
 
  59struct mem_cgroup *root_mem_cgroup __read_mostly;
  60
  61#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
  62/* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
  63int do_swap_account __read_mostly;
  64
  65/* for remember boot option*/
  66#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED
  67static int really_do_swap_account __initdata = 1;
  68#else
  69static int really_do_swap_account __initdata = 0;
  70#endif
  71
 
 
 
  72#else
  73#define do_swap_account		(0)
  74#endif
  75
 
 
 
 
 
  76
  77/*
  78 * Statistics for memory cgroup.
  79 */
  80enum mem_cgroup_stat_index {
  81	/*
  82	 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
  83	 */
  84	MEM_CGROUP_STAT_CACHE, 	   /* # of pages charged as cache */
  85	MEM_CGROUP_STAT_RSS,	   /* # of pages charged as anon rss */
  86	MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */
  87	MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
  88	MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */
  89	MEM_CGROUP_ON_MOVE,	/* someone is moving account between groups */
  90	MEM_CGROUP_STAT_NSTATS,
  91};
  92
  93enum mem_cgroup_events_index {
  94	MEM_CGROUP_EVENTS_PGPGIN,	/* # of pages paged in */
  95	MEM_CGROUP_EVENTS_PGPGOUT,	/* # of pages paged out */
  96	MEM_CGROUP_EVENTS_COUNT,	/* # of pages paged in/out */
  97	MEM_CGROUP_EVENTS_PGFAULT,	/* # of page-faults */
  98	MEM_CGROUP_EVENTS_PGMAJFAULT,	/* # of major page-faults */
  99	MEM_CGROUP_EVENTS_NSTATS,
 100};
 101/*
 102 * Per memcg event counter is incremented at every pagein/pageout. With THP,
 103 * it will be incremated by the number of pages. This counter is used for
 104 * for trigger some periodic events. This is straightforward and better
 105 * than using jiffies etc. to handle periodic memcg event.
 106 */
 107enum mem_cgroup_events_target {
 108	MEM_CGROUP_TARGET_THRESH,
 109	MEM_CGROUP_TARGET_SOFTLIMIT,
 110	MEM_CGROUP_TARGET_NUMAINFO,
 111	MEM_CGROUP_NTARGETS,
 112};
 113#define THRESHOLDS_EVENTS_TARGET (128)
 114#define SOFTLIMIT_EVENTS_TARGET (1024)
 115#define NUMAINFO_EVENTS_TARGET	(1024)
 116
 117struct mem_cgroup_stat_cpu {
 118	long count[MEM_CGROUP_STAT_NSTATS];
 119	unsigned long events[MEM_CGROUP_EVENTS_NSTATS];
 120	unsigned long targets[MEM_CGROUP_NTARGETS];
 121};
 122
 123/*
 124 * per-zone information in memory controller.
 125 */
 126struct mem_cgroup_per_zone {
 127	/*
 128	 * spin_lock to protect the per cgroup LRU
 129	 */
 130	struct list_head	lists[NR_LRU_LISTS];
 131	unsigned long		count[NR_LRU_LISTS];
 132
 133	struct zone_reclaim_stat reclaim_stat;
 134	struct rb_node		tree_node;	/* RB tree node */
 135	unsigned long long	usage_in_excess;/* Set to the value by which */
 136						/* the soft limit is exceeded*/
 137	bool			on_tree;
 138	struct mem_cgroup	*mem;		/* Back pointer, we cannot */
 139						/* use container_of	   */
 140};
 141/* Macro for accessing counter */
 142#define MEM_CGROUP_ZSTAT(mz, idx)	((mz)->count[(idx)])
 143
 144struct mem_cgroup_per_node {
 145	struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
 
 
 
 
 146};
 147
 148struct mem_cgroup_lru_info {
 149	struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES];
 150};
 151
 152/*
 153 * Cgroups above their limits are maintained in a RB-Tree, independent of
 154 * their hierarchy representation
 155 */
 156
 157struct mem_cgroup_tree_per_zone {
 158	struct rb_root rb_root;
 159	spinlock_t lock;
 160};
 161
 162struct mem_cgroup_tree_per_node {
 163	struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
 164};
 165
 166struct mem_cgroup_tree {
 167	struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
 168};
 169
 170static struct mem_cgroup_tree soft_limit_tree __read_mostly;
 171
 172struct mem_cgroup_threshold {
 173	struct eventfd_ctx *eventfd;
 174	u64 threshold;
 175};
 176
 177/* For threshold */
 178struct mem_cgroup_threshold_ary {
 179	/* An array index points to threshold just below usage. */
 180	int current_threshold;
 181	/* Size of entries[] */
 182	unsigned int size;
 183	/* Array of thresholds */
 184	struct mem_cgroup_threshold entries[0];
 185};
 186
 187struct mem_cgroup_thresholds {
 188	/* Primary thresholds array */
 189	struct mem_cgroup_threshold_ary *primary;
 190	/*
 191	 * Spare threshold array.
 192	 * This is needed to make mem_cgroup_unregister_event() "never fail".
 193	 * It must be able to store at least primary->size - 1 entries.
 194	 */
 195	struct mem_cgroup_threshold_ary *spare;
 196};
 197
 198/* for OOM */
 199struct mem_cgroup_eventfd_list {
 200	struct list_head list;
 201	struct eventfd_ctx *eventfd;
 202};
 203
 204static void mem_cgroup_threshold(struct mem_cgroup *mem);
 205static void mem_cgroup_oom_notify(struct mem_cgroup *mem);
 206
 207/*
 208 * The memory controller data structure. The memory controller controls both
 209 * page cache and RSS per cgroup. We would eventually like to provide
 210 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
 211 * to help the administrator determine what knobs to tune.
 212 *
 213 * TODO: Add a water mark for the memory controller. Reclaim will begin when
 214 * we hit the water mark. May be even add a low water mark, such that
 215 * no reclaim occurs from a cgroup at it's low water mark, this is
 216 * a feature that will be implemented much later in the future.
 217 */
 218struct mem_cgroup {
 219	struct cgroup_subsys_state css;
 220	/*
 221	 * the counter to account for memory usage
 222	 */
 223	struct res_counter res;
 224	/*
 225	 * the counter to account for mem+swap usage.
 226	 */
 227	struct res_counter memsw;
 228	/*
 229	 * Per cgroup active and inactive list, similar to the
 230	 * per zone LRU lists.
 231	 */
 232	struct mem_cgroup_lru_info info;
 233	/*
 234	 * While reclaiming in a hierarchy, we cache the last child we
 235	 * reclaimed from.
 236	 */
 237	int last_scanned_child;
 238	int last_scanned_node;
 239#if MAX_NUMNODES > 1
 240	nodemask_t	scan_nodes;
 241	atomic_t	numainfo_events;
 242	atomic_t	numainfo_updating;
 243#endif
 244	/*
 245	 * Should the accounting and control be hierarchical, per subtree?
 246	 */
 247	bool use_hierarchy;
 248
 249	bool		oom_lock;
 250	atomic_t	under_oom;
 251
 252	atomic_t	refcnt;
 253
 254	int	swappiness;
 255	/* OOM-Killer disable */
 256	int		oom_kill_disable;
 257
 258	/* set when res.limit == memsw.limit */
 259	bool		memsw_is_minimum;
 260
 261	/* protect arrays of thresholds */
 262	struct mutex thresholds_lock;
 263
 264	/* thresholds for memory usage. RCU-protected */
 265	struct mem_cgroup_thresholds thresholds;
 266
 267	/* thresholds for mem+swap usage. RCU-protected */
 268	struct mem_cgroup_thresholds memsw_thresholds;
 269
 270	/* For oom notifier event fd */
 271	struct list_head oom_notify;
 272
 273	/*
 274	 * Should we move charges of a task when a task is moved into this
 275	 * mem_cgroup ? And what type of charges should we move ?
 276	 */
 277	unsigned long 	move_charge_at_immigrate;
 278	/*
 279	 * percpu counter.
 280	 */
 281	struct mem_cgroup_stat_cpu *stat;
 282	/*
 283	 * used when a cpu is offlined or other synchronizations
 284	 * See mem_cgroup_read_stat().
 285	 */
 286	struct mem_cgroup_stat_cpu nocpu_base;
 287	spinlock_t pcp_counter_lock;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 288};
 289
 
 
 
 290/* Stuffs for move charges at task migration. */
 291/*
 292 * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a
 293 * left-shifted bitmap of these types.
 294 */
 295enum move_type {
 296	MOVE_CHARGE_TYPE_ANON,	/* private anonymous page and swap of it */
 297	MOVE_CHARGE_TYPE_FILE,	/* file page(including tmpfs) and swap of it */
 298	NR_MOVE_TYPE,
 299};
 300
 301/* "mc" and its members are protected by cgroup_mutex */
 302static struct move_charge_struct {
 303	spinlock_t	  lock; /* for from, to */
 
 304	struct mem_cgroup *from;
 305	struct mem_cgroup *to;
 
 306	unsigned long precharge;
 307	unsigned long moved_charge;
 308	unsigned long moved_swap;
 309	struct task_struct *moving_task;	/* a task moving charges */
 310	wait_queue_head_t waitq;		/* a waitq for other context */
 311} mc = {
 312	.lock = __SPIN_LOCK_UNLOCKED(mc.lock),
 313	.waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
 314};
 315
 316static bool move_anon(void)
 317{
 318	return test_bit(MOVE_CHARGE_TYPE_ANON,
 319					&mc.to->move_charge_at_immigrate);
 320}
 321
 322static bool move_file(void)
 323{
 324	return test_bit(MOVE_CHARGE_TYPE_FILE,
 325					&mc.to->move_charge_at_immigrate);
 326}
 327
 328/*
 329 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
 330 * limit reclaim to prevent infinite loops, if they ever occur.
 331 */
 332#define	MEM_CGROUP_MAX_RECLAIM_LOOPS		(100)
 333#define	MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS	(2)
 334
 335enum charge_type {
 336	MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
 337	MEM_CGROUP_CHARGE_TYPE_MAPPED,
 338	MEM_CGROUP_CHARGE_TYPE_SHMEM,	/* used by page migration of shmem */
 339	MEM_CGROUP_CHARGE_TYPE_FORCE,	/* used by force_empty */
 340	MEM_CGROUP_CHARGE_TYPE_SWAPOUT,	/* for accounting swapcache */
 341	MEM_CGROUP_CHARGE_TYPE_DROP,	/* a page was unused swap cache */
 342	NR_CHARGE_TYPE,
 343};
 344
 345/* for encoding cft->private value on file */
 346#define _MEM			(0)
 347#define _MEMSWAP		(1)
 348#define _OOM_TYPE		(2)
 349#define MEMFILE_PRIVATE(x, val)	(((x) << 16) | (val))
 350#define MEMFILE_TYPE(val)	(((val) >> 16) & 0xffff)
 
 
 
 
 
 351#define MEMFILE_ATTR(val)	((val) & 0xffff)
 352/* Used for OOM nofiier */
 353#define OOM_CONTROL		(0)
 354
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 355/*
 356 * Reclaim flags for mem_cgroup_hierarchical_reclaim
 
 
 
 
 
 
 
 
 
 357 */
 358#define MEM_CGROUP_RECLAIM_NOSWAP_BIT	0x0
 359#define MEM_CGROUP_RECLAIM_NOSWAP	(1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
 360#define MEM_CGROUP_RECLAIM_SHRINK_BIT	0x1
 361#define MEM_CGROUP_RECLAIM_SHRINK	(1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
 362#define MEM_CGROUP_RECLAIM_SOFT_BIT	0x2
 363#define MEM_CGROUP_RECLAIM_SOFT		(1 << MEM_CGROUP_RECLAIM_SOFT_BIT)
 364
 365static void mem_cgroup_get(struct mem_cgroup *mem);
 366static void mem_cgroup_put(struct mem_cgroup *mem);
 367static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
 368static void drain_all_stock_async(struct mem_cgroup *mem);
 
 
 369
 370static struct mem_cgroup_per_zone *
 371mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 372{
 373	return &mem->info.nodeinfo[nid]->zoneinfo[zid];
 
 
 
 
 
 
 
 374}
 375
 376struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem)
 
 
 
 
 
 
 
 
 
 
 
 
 
 377{
 378	return &mem->css;
 
 
 
 
 
 
 
 
 
 
 379}
 380
 381static struct mem_cgroup_per_zone *
 382page_cgroup_zoneinfo(struct mem_cgroup *mem, struct page *page)
 383{
 384	int nid = page_to_nid(page);
 385	int zid = page_zonenum(page);
 386
 387	return mem_cgroup_zoneinfo(mem, nid, zid);
 388}
 389
 390static struct mem_cgroup_tree_per_zone *
 391soft_limit_tree_node_zone(int nid, int zid)
 392{
 393	return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
 394}
 395
 396static struct mem_cgroup_tree_per_zone *
 397soft_limit_tree_from_page(struct page *page)
 398{
 399	int nid = page_to_nid(page);
 400	int zid = page_zonenum(page);
 401
 402	return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
 403}
 404
 405static void
 406__mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
 407				struct mem_cgroup_per_zone *mz,
 408				struct mem_cgroup_tree_per_zone *mctz,
 409				unsigned long long new_usage_in_excess)
 410{
 411	struct rb_node **p = &mctz->rb_root.rb_node;
 412	struct rb_node *parent = NULL;
 413	struct mem_cgroup_per_zone *mz_node;
 414
 415	if (mz->on_tree)
 416		return;
 417
 418	mz->usage_in_excess = new_usage_in_excess;
 419	if (!mz->usage_in_excess)
 420		return;
 421	while (*p) {
 422		parent = *p;
 423		mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
 424					tree_node);
 425		if (mz->usage_in_excess < mz_node->usage_in_excess)
 426			p = &(*p)->rb_left;
 427		/*
 428		 * We can't avoid mem cgroups that are over their soft
 429		 * limit by the same amount
 430		 */
 431		else if (mz->usage_in_excess >= mz_node->usage_in_excess)
 432			p = &(*p)->rb_right;
 433	}
 434	rb_link_node(&mz->tree_node, parent, p);
 435	rb_insert_color(&mz->tree_node, &mctz->rb_root);
 436	mz->on_tree = true;
 437}
 438
 439static void
 440__mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
 441				struct mem_cgroup_per_zone *mz,
 442				struct mem_cgroup_tree_per_zone *mctz)
 443{
 444	if (!mz->on_tree)
 445		return;
 446	rb_erase(&mz->tree_node, &mctz->rb_root);
 447	mz->on_tree = false;
 448}
 449
 450static void
 451mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
 452				struct mem_cgroup_per_zone *mz,
 453				struct mem_cgroup_tree_per_zone *mctz)
 454{
 455	spin_lock(&mctz->lock);
 456	__mem_cgroup_remove_exceeded(mem, mz, mctz);
 457	spin_unlock(&mctz->lock);
 
 
 458}
 459
 
 
 
 
 
 
 
 
 460
 461static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
 
 
 
 462{
 463	unsigned long long excess;
 464	struct mem_cgroup_per_zone *mz;
 465	struct mem_cgroup_tree_per_zone *mctz;
 466	int nid = page_to_nid(page);
 467	int zid = page_zonenum(page);
 468	mctz = soft_limit_tree_from_page(page);
 469
 
 470	/*
 471	 * Necessary to update all ancestors when hierarchy is used.
 472	 * because their event counter is not touched.
 473	 */
 474	for (; mem; mem = parent_mem_cgroup(mem)) {
 475		mz = mem_cgroup_zoneinfo(mem, nid, zid);
 476		excess = res_counter_soft_limit_excess(&mem->res);
 477		/*
 478		 * We have to update the tree if mz is on RB-tree or
 479		 * mem is over its softlimit.
 480		 */
 481		if (excess || mz->on_tree) {
 482			spin_lock(&mctz->lock);
 
 
 483			/* if on-tree, remove it */
 484			if (mz->on_tree)
 485				__mem_cgroup_remove_exceeded(mem, mz, mctz);
 486			/*
 487			 * Insert again. mz->usage_in_excess will be updated.
 488			 * If excess is 0, no tree ops.
 489			 */
 490			__mem_cgroup_insert_exceeded(mem, mz, mctz, excess);
 491			spin_unlock(&mctz->lock);
 492		}
 493	}
 494}
 495
 496static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem)
 497{
 498	int node, zone;
 499	struct mem_cgroup_per_zone *mz;
 500	struct mem_cgroup_tree_per_zone *mctz;
 
 
 501
 502	for_each_node_state(node, N_POSSIBLE) {
 503		for (zone = 0; zone < MAX_NR_ZONES; zone++) {
 504			mz = mem_cgroup_zoneinfo(mem, node, zone);
 505			mctz = soft_limit_tree_node_zone(node, zone);
 506			mem_cgroup_remove_exceeded(mem, mz, mctz);
 507		}
 508	}
 509}
 510
 511static struct mem_cgroup_per_zone *
 512__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
 513{
 514	struct rb_node *rightmost = NULL;
 515	struct mem_cgroup_per_zone *mz;
 516
 517retry:
 518	mz = NULL;
 519	rightmost = rb_last(&mctz->rb_root);
 520	if (!rightmost)
 521		goto done;		/* Nothing to reclaim from */
 522
 523	mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
 524	/*
 525	 * Remove the node now but someone else can add it back,
 526	 * we will to add it back at the end of reclaim to its correct
 527	 * position in the tree.
 528	 */
 529	__mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
 530	if (!res_counter_soft_limit_excess(&mz->mem->res) ||
 531		!css_tryget(&mz->mem->css))
 532		goto retry;
 533done:
 534	return mz;
 535}
 536
 537static struct mem_cgroup_per_zone *
 538mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
 539{
 540	struct mem_cgroup_per_zone *mz;
 541
 542	spin_lock(&mctz->lock);
 543	mz = __mem_cgroup_largest_soft_limit_node(mctz);
 544	spin_unlock(&mctz->lock);
 545	return mz;
 546}
 547
 548/*
 
 
 549 * Implementation Note: reading percpu statistics for memcg.
 550 *
 551 * Both of vmstat[] and percpu_counter has threshold and do periodic
 552 * synchronization to implement "quick" read. There are trade-off between
 553 * reading cost and precision of value. Then, we may have a chance to implement
 554 * a periodic synchronizion of counter in memcg's counter.
 555 *
 556 * But this _read() function is used for user interface now. The user accounts
 557 * memory usage by memory cgroup and he _always_ requires exact value because
 558 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
 559 * have to visit all online cpus and make sum. So, for now, unnecessary
 560 * synchronization is not implemented. (just implemented for cpu hotplug)
 561 *
 562 * If there are kernel internal actions which can make use of some not-exact
 563 * value, and reading all cpu value can be performance bottleneck in some
 564 * common workload, threashold and synchonization as vmstat[] should be
 565 * implemented.
 566 */
 567static long mem_cgroup_read_stat(struct mem_cgroup *mem,
 568				 enum mem_cgroup_stat_index idx)
 569{
 570	long val = 0;
 571	int cpu;
 572
 573	get_online_cpus();
 574	for_each_online_cpu(cpu)
 575		val += per_cpu(mem->stat->count[idx], cpu);
 576#ifdef CONFIG_HOTPLUG_CPU
 577	spin_lock(&mem->pcp_counter_lock);
 578	val += mem->nocpu_base.count[idx];
 579	spin_unlock(&mem->pcp_counter_lock);
 580#endif
 581	put_online_cpus();
 582	return val;
 583}
 584
 585static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,
 586					 bool charge)
 587{
 588	int val = (charge) ? 1 : -1;
 589	this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_SWAPOUT], val);
 590}
 591
 592void mem_cgroup_pgfault(struct mem_cgroup *mem, int val)
 593{
 594	this_cpu_add(mem->stat->events[MEM_CGROUP_EVENTS_PGFAULT], val);
 595}
 596
 597void mem_cgroup_pgmajfault(struct mem_cgroup *mem, int val)
 598{
 599	this_cpu_add(mem->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT], val);
 600}
 601
 602static unsigned long mem_cgroup_read_events(struct mem_cgroup *mem,
 603					    enum mem_cgroup_events_index idx)
 604{
 605	unsigned long val = 0;
 606	int cpu;
 607
 608	for_each_online_cpu(cpu)
 609		val += per_cpu(mem->stat->events[idx], cpu);
 610#ifdef CONFIG_HOTPLUG_CPU
 611	spin_lock(&mem->pcp_counter_lock);
 612	val += mem->nocpu_base.events[idx];
 613	spin_unlock(&mem->pcp_counter_lock);
 614#endif
 615	return val;
 616}
 617
 618static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
 619					 bool file, int nr_pages)
 
 620{
 621	preempt_disable();
 622
 623	if (file)
 624		__this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], nr_pages);
 
 
 
 625	else
 626		__this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], nr_pages);
 
 
 
 
 
 
 
 627
 628	/* pagein of a big page is an event. So, ignore page size */
 629	if (nr_pages > 0)
 630		__this_cpu_inc(mem->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
 631	else {
 632		__this_cpu_inc(mem->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
 633		nr_pages = -nr_pages; /* for event */
 634	}
 635
 636	__this_cpu_add(mem->stat->events[MEM_CGROUP_EVENTS_COUNT], nr_pages);
 637
 638	preempt_enable();
 639}
 640
 641unsigned long
 642mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *mem, int nid, int zid,
 643			unsigned int lru_mask)
 644{
 645	struct mem_cgroup_per_zone *mz;
 646	enum lru_list l;
 647	unsigned long ret = 0;
 648
 649	mz = mem_cgroup_zoneinfo(mem, nid, zid);
 650
 651	for_each_lru(l) {
 652		if (BIT(l) & lru_mask)
 653			ret += MEM_CGROUP_ZSTAT(mz, l);
 654	}
 655	return ret;
 656}
 657
 658static unsigned long
 659mem_cgroup_node_nr_lru_pages(struct mem_cgroup *mem,
 660			int nid, unsigned int lru_mask)
 661{
 662	u64 total = 0;
 663	int zid;
 664
 665	for (zid = 0; zid < MAX_NR_ZONES; zid++)
 666		total += mem_cgroup_zone_nr_lru_pages(mem, nid, zid, lru_mask);
 667
 668	return total;
 
 
 
 
 
 
 
 
 
 
 
 669}
 670
 671static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *mem,
 672			unsigned int lru_mask)
 673{
 
 674	int nid;
 675	u64 total = 0;
 676
 677	for_each_node_state(nid, N_HIGH_MEMORY)
 678		total += mem_cgroup_node_nr_lru_pages(mem, nid, lru_mask);
 679	return total;
 680}
 681
 682static bool __memcg_event_check(struct mem_cgroup *mem, int target)
 
 683{
 684	unsigned long val, next;
 685
 686	val = this_cpu_read(mem->stat->events[MEM_CGROUP_EVENTS_COUNT]);
 687	next = this_cpu_read(mem->stat->targets[target]);
 688	/* from time_after() in jiffies.h */
 689	return ((long)next - (long)val < 0);
 690}
 691
 692static void __mem_cgroup_target_update(struct mem_cgroup *mem, int target)
 693{
 694	unsigned long val, next;
 695
 696	val = this_cpu_read(mem->stat->events[MEM_CGROUP_EVENTS_COUNT]);
 697
 698	switch (target) {
 699	case MEM_CGROUP_TARGET_THRESH:
 700		next = val + THRESHOLDS_EVENTS_TARGET;
 701		break;
 702	case MEM_CGROUP_TARGET_SOFTLIMIT:
 703		next = val + SOFTLIMIT_EVENTS_TARGET;
 704		break;
 705	case MEM_CGROUP_TARGET_NUMAINFO:
 706		next = val + NUMAINFO_EVENTS_TARGET;
 707		break;
 708	default:
 709		return;
 710	}
 711
 712	this_cpu_write(mem->stat->targets[target], next);
 713}
 714
 715/*
 716 * Check events in order.
 717 *
 718 */
 719static void memcg_check_events(struct mem_cgroup *mem, struct page *page)
 720{
 721	/* threshold event is triggered in finer grain than soft limit */
 722	if (unlikely(__memcg_event_check(mem, MEM_CGROUP_TARGET_THRESH))) {
 723		mem_cgroup_threshold(mem);
 724		__mem_cgroup_target_update(mem, MEM_CGROUP_TARGET_THRESH);
 725		if (unlikely(__memcg_event_check(mem,
 726			     MEM_CGROUP_TARGET_SOFTLIMIT))) {
 727			mem_cgroup_update_tree(mem, page);
 728			__mem_cgroup_target_update(mem,
 729						   MEM_CGROUP_TARGET_SOFTLIMIT);
 730		}
 731#if MAX_NUMNODES > 1
 732		if (unlikely(__memcg_event_check(mem,
 733			MEM_CGROUP_TARGET_NUMAINFO))) {
 734			atomic_inc(&mem->numainfo_events);
 735			__mem_cgroup_target_update(mem,
 736				MEM_CGROUP_TARGET_NUMAINFO);
 737		}
 
 
 
 738#endif
 739	}
 740}
 741
 742static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
 743{
 744	return container_of(cgroup_subsys_state(cont,
 745				mem_cgroup_subsys_id), struct mem_cgroup,
 746				css);
 747}
 748
 749struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
 750{
 751	/*
 752	 * mm_update_next_owner() may clear mm->owner to NULL
 753	 * if it races with swapoff, page migration, etc.
 754	 * So this can be called with p == NULL.
 755	 */
 756	if (unlikely(!p))
 757		return NULL;
 758
 759	return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
 760				struct mem_cgroup, css);
 761}
 
 762
 763struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
 764{
 765	struct mem_cgroup *mem = NULL;
 766
 767	if (!mm)
 768		return NULL;
 769	/*
 770	 * Because we have no locks, mm->owner's may be being moved to other
 771	 * cgroup. We use css_tryget() here even if this looks
 772	 * pessimistic (rather than adding locks here).
 773	 */
 774	rcu_read_lock();
 775	do {
 776		mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
 777		if (unlikely(!mem))
 778			break;
 779	} while (!css_tryget(&mem->css));
 780	rcu_read_unlock();
 781	return mem;
 782}
 783
 784/* The caller has to guarantee "mem" exists before calling this */
 785static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *mem)
 786{
 787	struct cgroup_subsys_state *css;
 788	int found;
 789
 790	if (!mem) /* ROOT cgroup has the smallest ID */
 791		return root_mem_cgroup; /*css_put/get against root is ignored*/
 792	if (!mem->use_hierarchy) {
 793		if (css_tryget(&mem->css))
 794			return mem;
 795		return NULL;
 796	}
 797	rcu_read_lock();
 798	/*
 799	 * searching a memory cgroup which has the smallest ID under given
 800	 * ROOT cgroup. (ID >= 1)
 801	 */
 802	css = css_get_next(&mem_cgroup_subsys, 1, &mem->css, &found);
 803	if (css && css_tryget(css))
 804		mem = container_of(css, struct mem_cgroup, css);
 805	else
 806		mem = NULL;
 807	rcu_read_unlock();
 808	return mem;
 809}
 810
 811static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter,
 812					struct mem_cgroup *root,
 813					bool cond)
 814{
 815	int nextid = css_id(&iter->css) + 1;
 816	int found;
 817	int hierarchy_used;
 818	struct cgroup_subsys_state *css;
 819
 820	hierarchy_used = iter->use_hierarchy;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 821
 822	css_put(&iter->css);
 823	/* If no ROOT, walk all, ignore hierarchy */
 824	if (!cond || (root && !hierarchy_used))
 825		return NULL;
 826
 827	if (!root)
 828		root = root_mem_cgroup;
 829
 830	do {
 831		iter = NULL;
 832		rcu_read_lock();
 833
 834		css = css_get_next(&mem_cgroup_subsys, nextid,
 835				&root->css, &found);
 836		if (css && css_tryget(css))
 837			iter = container_of(css, struct mem_cgroup, css);
 838		rcu_read_unlock();
 839		/* If css is NULL, no more cgroups will be found */
 840		nextid = found + 1;
 841	} while (css && !iter);
 842
 843	return iter;
 844}
 845/*
 846 * for_eacn_mem_cgroup_tree() for visiting all cgroup under tree. Please
 847 * be careful that "break" loop is not allowed. We have reference count.
 848 * Instead of that modify "cond" to be false and "continue" to exit the loop.
 849 */
 850#define for_each_mem_cgroup_tree_cond(iter, root, cond)	\
 851	for (iter = mem_cgroup_start_loop(root);\
 852	     iter != NULL;\
 853	     iter = mem_cgroup_get_next(iter, root, cond))
 854
 855#define for_each_mem_cgroup_tree(iter, root) \
 856	for_each_mem_cgroup_tree_cond(iter, root, true)
 857
 858#define for_each_mem_cgroup_all(iter) \
 859	for_each_mem_cgroup_tree_cond(iter, NULL, true)
 860
 
 
 861
 862static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
 863{
 864	return (mem == root_mem_cgroup);
 865}
 
 
 
 
 
 
 
 
 
 
 
 866
 867void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
 868{
 869	struct mem_cgroup *mem;
 870
 871	if (!mm)
 872		return;
 
 
 
 
 
 
 
 
 
 
 
 873
 874	rcu_read_lock();
 875	mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
 876	if (unlikely(!mem))
 877		goto out;
 
 
 878
 879	switch (idx) {
 880	case PGMAJFAULT:
 881		mem_cgroup_pgmajfault(mem, 1);
 882		break;
 883	case PGFAULT:
 884		mem_cgroup_pgfault(mem, 1);
 885		break;
 886	default:
 887		BUG();
 888	}
 889out:
 890	rcu_read_unlock();
 891}
 892EXPORT_SYMBOL(mem_cgroup_count_vm_event);
 893
 894/*
 895 * Following LRU functions are allowed to be used without PCG_LOCK.
 896 * Operations are called by routine of global LRU independently from memcg.
 897 * What we have to take care of here is validness of pc->mem_cgroup.
 898 *
 899 * Changes to pc->mem_cgroup happens when
 900 * 1. charge
 901 * 2. moving account
 902 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
 903 * It is added to LRU before charge.
 904 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
 905 * When moving account, the page is not on LRU. It's isolated.
 906 */
 907
 908void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
 909{
 910	struct page_cgroup *pc;
 911	struct mem_cgroup_per_zone *mz;
 912
 913	if (mem_cgroup_disabled())
 914		return;
 915	pc = lookup_page_cgroup(page);
 916	/* can happen while we handle swapcache. */
 917	if (!TestClearPageCgroupAcctLRU(pc))
 918		return;
 919	VM_BUG_ON(!pc->mem_cgroup);
 920	/*
 921	 * We don't check PCG_USED bit. It's cleared when the "page" is finally
 922	 * removed from global LRU.
 923	 */
 924	mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
 925	/* huge page split is done under lru_lock. so, we have no races. */
 926	MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page);
 927	if (mem_cgroup_is_root(pc->mem_cgroup))
 928		return;
 929	VM_BUG_ON(list_empty(&pc->lru));
 930	list_del_init(&pc->lru);
 931}
 932
 933void mem_cgroup_del_lru(struct page *page)
 934{
 935	mem_cgroup_del_lru_list(page, page_lru(page));
 936}
 937
 938/*
 939 * Writeback is about to end against a page which has been marked for immediate
 940 * reclaim.  If it still appears to be reclaimable, move it to the tail of the
 941 * inactive list.
 942 */
 943void mem_cgroup_rotate_reclaimable_page(struct page *page)
 944{
 945	struct mem_cgroup_per_zone *mz;
 946	struct page_cgroup *pc;
 947	enum lru_list lru = page_lru(page);
 948
 949	if (mem_cgroup_disabled())
 950		return;
 
 
 
 951
 952	pc = lookup_page_cgroup(page);
 953	/* unused or root page is not rotated. */
 954	if (!PageCgroupUsed(pc))
 955		return;
 956	/* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
 957	smp_rmb();
 958	if (mem_cgroup_is_root(pc->mem_cgroup))
 959		return;
 960	mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
 961	list_move_tail(&pc->lru, &mz->lists[lru]);
 962}
 963
 964void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
 
 
 
 
 
 
 965{
 966	struct mem_cgroup_per_zone *mz;
 967	struct page_cgroup *pc;
 968
 969	if (mem_cgroup_disabled())
 970		return;
 971
 972	pc = lookup_page_cgroup(page);
 973	/* unused or root page is not rotated. */
 974	if (!PageCgroupUsed(pc))
 975		return;
 976	/* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
 977	smp_rmb();
 978	if (mem_cgroup_is_root(pc->mem_cgroup))
 979		return;
 980	mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
 981	list_move(&pc->lru, &mz->lists[lru]);
 982}
 983
 984void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
 985{
 986	struct page_cgroup *pc;
 
 987	struct mem_cgroup_per_zone *mz;
 
 
 988
 989	if (mem_cgroup_disabled())
 990		return;
 991	pc = lookup_page_cgroup(page);
 992	VM_BUG_ON(PageCgroupAcctLRU(pc));
 993	if (!PageCgroupUsed(pc))
 994		return;
 995	/* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
 996	smp_rmb();
 997	mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
 998	/* huge page split is done under lru_lock. so, we have no races. */
 999	MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page);
1000	SetPageCgroupAcctLRU(pc);
1001	if (mem_cgroup_is_root(pc->mem_cgroup))
1002		return;
1003	list_add(&pc->lru, &mz->lists[lru]);
1004}
1005
1006/*
1007 * At handling SwapCache and other FUSE stuff, pc->mem_cgroup may be changed
1008 * while it's linked to lru because the page may be reused after it's fully
1009 * uncharged. To handle that, unlink page_cgroup from LRU when charge it again.
1010 * It's done under lock_page and expected that zone->lru_lock isnever held.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1011 */
1012static void mem_cgroup_lru_del_before_commit(struct page *page)
 
1013{
1014	unsigned long flags;
1015	struct zone *zone = page_zone(page);
1016	struct page_cgroup *pc = lookup_page_cgroup(page);
1017
1018	/*
1019	 * Doing this check without taking ->lru_lock seems wrong but this
1020	 * is safe. Because if page_cgroup's USED bit is unset, the page
1021	 * will not be added to any memcg's LRU. If page_cgroup's USED bit is
1022	 * set, the commit after this will fail, anyway.
1023	 * This all charge/uncharge is done under some mutual execustion.
1024	 * So, we don't need to taking care of changes in USED bit.
1025	 */
1026	if (likely(!PageLRU(page)))
1027		return;
1028
1029	spin_lock_irqsave(&zone->lru_lock, flags);
 
 
1030	/*
1031	 * Forget old LRU when this page_cgroup is *not* used. This Used bit
1032	 * is guarded by lock_page() because the page is SwapCache.
1033	 */
1034	if (!PageCgroupUsed(pc))
1035		mem_cgroup_del_lru_list(page, page_lru(page));
1036	spin_unlock_irqrestore(&zone->lru_lock, flags);
1037}
1038
1039static void mem_cgroup_lru_add_after_commit(struct page *page)
1040{
1041	unsigned long flags;
1042	struct zone *zone = page_zone(page);
1043	struct page_cgroup *pc = lookup_page_cgroup(page);
1044
1045	/* taking care of that the page is added to LRU while we commit it */
1046	if (likely(!PageLRU(page)))
1047		return;
1048	spin_lock_irqsave(&zone->lru_lock, flags);
1049	/* link when the page is linked to LRU but page_cgroup isn't */
1050	if (PageLRU(page) && !PageCgroupAcctLRU(pc))
1051		mem_cgroup_add_lru_list(page, page_lru(page));
1052	spin_unlock_irqrestore(&zone->lru_lock, flags);
1053}
1054
1055
1056void mem_cgroup_move_lists(struct page *page,
1057			   enum lru_list from, enum lru_list to)
1058{
1059	if (mem_cgroup_disabled())
1060		return;
1061	mem_cgroup_del_lru_list(page, from);
1062	mem_cgroup_add_lru_list(page, to);
1063}
1064
1065/*
1066 * Checks whether given mem is same or in the root_mem's
1067 * hierarchy subtree
 
 
 
 
 
1068 */
1069static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_mem,
1070		struct mem_cgroup *mem)
1071{
1072	if (root_mem != mem) {
1073		return (root_mem->use_hierarchy &&
1074			css_is_ancestor(&mem->css, &root_mem->css));
1075	}
1076
1077	return true;
1078}
1079
1080int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
1081{
1082	int ret;
1083	struct mem_cgroup *curr = NULL;
1084	struct task_struct *p;
1085
1086	p = find_lock_task_mm(task);
1087	if (!p)
1088		return 0;
1089	curr = try_get_mem_cgroup_from_mm(p->mm);
1090	task_unlock(p);
1091	if (!curr)
1092		return 0;
1093	/*
1094	 * We should check use_hierarchy of "mem" not "curr". Because checking
1095	 * use_hierarchy of "curr" here make this function true if hierarchy is
1096	 * enabled in "curr" and "curr" is a child of "mem" in *cgroup*
1097	 * hierarchy(even if use_hierarchy is disabled in "mem").
1098	 */
1099	ret = mem_cgroup_same_or_subtree(mem, curr);
1100	css_put(&curr->css);
1101	return ret;
1102}
1103
1104static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
1105{
1106	unsigned long active;
1107	unsigned long inactive;
1108	unsigned long gb;
1109	unsigned long inactive_ratio;
1110
1111	inactive = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_INACTIVE_ANON));
1112	active = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_ACTIVE_ANON));
1113
1114	gb = (inactive + active) >> (30 - PAGE_SHIFT);
1115	if (gb)
1116		inactive_ratio = int_sqrt(10 * gb);
1117	else
1118		inactive_ratio = 1;
1119
1120	if (present_pages) {
1121		present_pages[0] = inactive;
1122		present_pages[1] = active;
1123	}
1124
1125	return inactive_ratio;
1126}
1127
1128int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
1129{
1130	unsigned long active;
1131	unsigned long inactive;
1132	unsigned long present_pages[2];
1133	unsigned long inactive_ratio;
1134
1135	inactive_ratio = calc_inactive_ratio(memcg, present_pages);
1136
1137	inactive = present_pages[0];
1138	active = present_pages[1];
1139
1140	if (inactive * inactive_ratio < active)
1141		return 1;
1142
1143	return 0;
1144}
1145
1146int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)
1147{
1148	unsigned long active;
1149	unsigned long inactive;
1150
1151	inactive = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_INACTIVE_FILE));
1152	active = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_ACTIVE_FILE));
1153
1154	return (active > inactive);
1155}
1156
1157struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
1158						      struct zone *zone)
1159{
1160	int nid = zone_to_nid(zone);
1161	int zid = zone_idx(zone);
1162	struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
1163
1164	return &mz->reclaim_stat;
 
 
 
 
 
 
 
 
 
 
1165}
1166
1167struct zone_reclaim_stat *
1168mem_cgroup_get_reclaim_stat_from_page(struct page *page)
 
 
 
 
 
 
 
 
 
1169{
1170	struct page_cgroup *pc;
1171	struct mem_cgroup_per_zone *mz;
 
1172
1173	if (mem_cgroup_disabled())
1174		return NULL;
1175
1176	pc = lookup_page_cgroup(page);
1177	if (!PageCgroupUsed(pc))
1178		return NULL;
1179	/* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
1180	smp_rmb();
1181	mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
1182	return &mz->reclaim_stat;
1183}
1184
1185unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
1186					struct list_head *dst,
1187					unsigned long *scanned, int order,
1188					int mode, struct zone *z,
1189					struct mem_cgroup *mem_cont,
1190					int active, int file)
1191{
1192	unsigned long nr_taken = 0;
1193	struct page *page;
1194	unsigned long scan;
1195	LIST_HEAD(pc_list);
1196	struct list_head *src;
1197	struct page_cgroup *pc, *tmp;
1198	int nid = zone_to_nid(z);
1199	int zid = zone_idx(z);
1200	struct mem_cgroup_per_zone *mz;
1201	int lru = LRU_FILE * file + active;
1202	int ret;
1203
1204	BUG_ON(!mem_cont);
1205	mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
1206	src = &mz->lists[lru];
1207
1208	scan = 0;
1209	list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
1210		if (scan >= nr_to_scan)
1211			break;
1212
1213		if (unlikely(!PageCgroupUsed(pc)))
1214			continue;
1215
1216		page = lookup_cgroup_page(pc);
1217
1218		if (unlikely(!PageLRU(page)))
1219			continue;
1220
1221		scan++;
1222		ret = __isolate_lru_page(page, mode, file);
1223		switch (ret) {
1224		case 0:
1225			list_move(&page->lru, dst);
1226			mem_cgroup_del_lru(page);
1227			nr_taken += hpage_nr_pages(page);
1228			break;
1229		case -EBUSY:
1230			/* we don't affect global LRU but rotate in our LRU */
1231			mem_cgroup_rotate_lru_list(page, page_lru(page));
1232			break;
1233		default:
1234			break;
1235		}
1236	}
1237
1238	*scanned = scan;
1239
1240	trace_mm_vmscan_memcg_isolate(0, nr_to_scan, scan, nr_taken,
1241				      0, 0, 0, mode);
1242
1243	return nr_taken;
1244}
1245
1246#define mem_cgroup_from_res_counter(counter, member)	\
1247	container_of(counter, struct mem_cgroup, member)
1248
1249/**
1250 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1251 * @mem: the memory cgroup
1252 *
1253 * Returns the maximum amount of memory @mem can be charged with, in
1254 * pages.
1255 */
1256static unsigned long mem_cgroup_margin(struct mem_cgroup *mem)
1257{
1258	unsigned long long margin;
 
 
1259
1260	margin = res_counter_margin(&mem->res);
1261	if (do_swap_account)
1262		margin = min(margin, res_counter_margin(&mem->memsw));
1263	return margin >> PAGE_SHIFT;
1264}
1265
1266int mem_cgroup_swappiness(struct mem_cgroup *memcg)
1267{
1268	struct cgroup *cgrp = memcg->css.cgroup;
1269
1270	/* root ? */
1271	if (cgrp->parent == NULL)
1272		return vm_swappiness;
1273
1274	return memcg->swappiness;
1275}
1276
1277static void mem_cgroup_start_move(struct mem_cgroup *mem)
1278{
1279	int cpu;
1280
1281	get_online_cpus();
1282	spin_lock(&mem->pcp_counter_lock);
1283	for_each_online_cpu(cpu)
1284		per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1;
1285	mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1;
1286	spin_unlock(&mem->pcp_counter_lock);
1287	put_online_cpus();
1288
1289	synchronize_rcu();
1290}
1291
1292static void mem_cgroup_end_move(struct mem_cgroup *mem)
1293{
1294	int cpu;
1295
1296	if (!mem)
1297		return;
1298	get_online_cpus();
1299	spin_lock(&mem->pcp_counter_lock);
1300	for_each_online_cpu(cpu)
1301		per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1;
1302	mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1;
1303	spin_unlock(&mem->pcp_counter_lock);
1304	put_online_cpus();
1305}
1306/*
1307 * 2 routines for checking "mem" is under move_account() or not.
1308 *
1309 * mem_cgroup_stealed() - checking a cgroup is mc.from or not. This is used
1310 *			  for avoiding race in accounting. If true,
1311 *			  pc->mem_cgroup may be overwritten.
1312 *
1313 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1314 *			  under hierarchy of moving cgroups. This is for
1315 *			  waiting at hith-memory prressure caused by "move".
1316 */
1317
1318static bool mem_cgroup_stealed(struct mem_cgroup *mem)
1319{
1320	VM_BUG_ON(!rcu_read_lock_held());
1321	return this_cpu_read(mem->stat->count[MEM_CGROUP_ON_MOVE]) > 0;
1322}
1323
1324static bool mem_cgroup_under_move(struct mem_cgroup *mem)
1325{
1326	struct mem_cgroup *from;
1327	struct mem_cgroup *to;
1328	bool ret = false;
1329	/*
1330	 * Unlike task_move routines, we access mc.to, mc.from not under
1331	 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1332	 */
1333	spin_lock(&mc.lock);
1334	from = mc.from;
1335	to = mc.to;
1336	if (!from)
1337		goto unlock;
1338
1339	ret = mem_cgroup_same_or_subtree(mem, from)
1340		|| mem_cgroup_same_or_subtree(mem, to);
1341unlock:
1342	spin_unlock(&mc.lock);
1343	return ret;
1344}
1345
1346static bool mem_cgroup_wait_acct_move(struct mem_cgroup *mem)
1347{
1348	if (mc.moving_task && current != mc.moving_task) {
1349		if (mem_cgroup_under_move(mem)) {
1350			DEFINE_WAIT(wait);
1351			prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1352			/* moving charge context might have finished. */
1353			if (mc.moving_task)
1354				schedule();
1355			finish_wait(&mc.waitq, &wait);
1356			return true;
1357		}
1358	}
1359	return false;
1360}
1361
 
1362/**
1363 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
1364 * @memcg: The memory cgroup that went over limit
1365 * @p: Task that is going to be killed
1366 *
1367 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1368 * enabled
1369 */
1370void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1371{
1372	struct cgroup *task_cgrp;
1373	struct cgroup *mem_cgrp;
1374	/*
1375	 * Need a buffer in BSS, can't rely on allocations. The code relies
1376	 * on the assumption that OOM is serialized for memory controller.
1377	 * If this assumption is broken, revisit this code.
1378	 */
1379	static char memcg_name[PATH_MAX];
1380	int ret;
1381
1382	if (!memcg || !p)
1383		return;
1384
1385
1386	rcu_read_lock();
1387
1388	mem_cgrp = memcg->css.cgroup;
1389	task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
1390
1391	ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
1392	if (ret < 0) {
1393		/*
1394		 * Unfortunately, we are unable to convert to a useful name
1395		 * But we'll still print out the usage information
1396		 */
1397		rcu_read_unlock();
1398		goto done;
1399	}
1400	rcu_read_unlock();
1401
1402	printk(KERN_INFO "Task in %s killed", memcg_name);
 
1403
1404	rcu_read_lock();
1405	ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
1406	if (ret < 0) {
1407		rcu_read_unlock();
1408		goto done;
1409	}
1410	rcu_read_unlock();
1411
1412	/*
1413	 * Continues from above, so we don't need an KERN_ level
1414	 */
1415	printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
1416done:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1417
1418	printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
1419		res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1420		res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1421		res_counter_read_u64(&memcg->res, RES_FAILCNT));
1422	printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
1423		"failcnt %llu\n",
1424		res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1425		res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1426		res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
1427}
1428
1429/*
1430 * This function returns the number of memcg under hierarchy tree. Returns
1431 * 1(self count) if no children.
1432 */
1433static int mem_cgroup_count_children(struct mem_cgroup *mem)
1434{
1435	int num = 0;
1436	struct mem_cgroup *iter;
1437
1438	for_each_mem_cgroup_tree(iter, mem)
1439		num++;
1440	return num;
1441}
1442
1443/*
1444 * Return the memory (and swap, if configured) limit for a memcg.
1445 */
1446u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
1447{
1448	u64 limit;
1449	u64 memsw;
1450
1451	limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
1452	limit += total_swap_pages << PAGE_SHIFT;
 
 
1453
1454	memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1455	/*
1456	 * If memsw is finite and limits the amount of swap space available
1457	 * to this memcg, return that limit.
1458	 */
1459	return min(limit, memsw);
1460}
1461
1462/*
1463 * Visit the first child (need not be the first child as per the ordering
1464 * of the cgroup list, since we track last_scanned_child) of @mem and use
1465 * that to reclaim free pages from.
1466 */
1467static struct mem_cgroup *
1468mem_cgroup_select_victim(struct mem_cgroup *root_mem)
1469{
1470	struct mem_cgroup *ret = NULL;
1471	struct cgroup_subsys_state *css;
1472	int nextid, found;
1473
1474	if (!root_mem->use_hierarchy) {
1475		css_get(&root_mem->css);
1476		ret = root_mem;
1477	}
 
 
 
1478
1479	while (!ret) {
1480		rcu_read_lock();
1481		nextid = root_mem->last_scanned_child + 1;
1482		css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
1483				   &found);
1484		if (css && css_tryget(css))
1485			ret = container_of(css, struct mem_cgroup, css);
1486
1487		rcu_read_unlock();
1488		/* Updates scanning parameter */
1489		if (!css) {
1490			/* this means start scan from ID:1 */
1491			root_mem->last_scanned_child = 0;
1492		} else
1493			root_mem->last_scanned_child = found;
 
1494	}
1495
1496	return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1497}
1498
 
 
1499/**
1500 * test_mem_cgroup_node_reclaimable
1501 * @mem: the target memcg
1502 * @nid: the node ID to be checked.
1503 * @noswap : specify true here if the user wants flle only information.
1504 *
1505 * This function returns whether the specified memcg contains any
1506 * reclaimable pages on a node. Returns true if there are any reclaimable
1507 * pages in the node.
1508 */
1509static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *mem,
1510		int nid, bool noswap)
1511{
1512	if (mem_cgroup_node_nr_lru_pages(mem, nid, LRU_ALL_FILE))
1513		return true;
1514	if (noswap || !total_swap_pages)
1515		return false;
1516	if (mem_cgroup_node_nr_lru_pages(mem, nid, LRU_ALL_ANON))
1517		return true;
1518	return false;
1519
1520}
1521#if MAX_NUMNODES > 1
1522
1523/*
1524 * Always updating the nodemask is not very good - even if we have an empty
1525 * list or the wrong list here, we can start from some node and traverse all
1526 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1527 *
1528 */
1529static void mem_cgroup_may_update_nodemask(struct mem_cgroup *mem)
1530{
1531	int nid;
1532	/*
1533	 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1534	 * pagein/pageout changes since the last update.
1535	 */
1536	if (!atomic_read(&mem->numainfo_events))
1537		return;
1538	if (atomic_inc_return(&mem->numainfo_updating) > 1)
1539		return;
1540
1541	/* make a nodemask where this memcg uses memory from */
1542	mem->scan_nodes = node_states[N_HIGH_MEMORY];
1543
1544	for_each_node_mask(nid, node_states[N_HIGH_MEMORY]) {
1545
1546		if (!test_mem_cgroup_node_reclaimable(mem, nid, false))
1547			node_clear(nid, mem->scan_nodes);
1548	}
1549
1550	atomic_set(&mem->numainfo_events, 0);
1551	atomic_set(&mem->numainfo_updating, 0);
1552}
1553
1554/*
1555 * Selecting a node where we start reclaim from. Because what we need is just
1556 * reducing usage counter, start from anywhere is O,K. Considering
1557 * memory reclaim from current node, there are pros. and cons.
1558 *
1559 * Freeing memory from current node means freeing memory from a node which
1560 * we'll use or we've used. So, it may make LRU bad. And if several threads
1561 * hit limits, it will see a contention on a node. But freeing from remote
1562 * node means more costs for memory reclaim because of memory latency.
1563 *
1564 * Now, we use round-robin. Better algorithm is welcomed.
1565 */
1566int mem_cgroup_select_victim_node(struct mem_cgroup *mem)
1567{
1568	int node;
1569
1570	mem_cgroup_may_update_nodemask(mem);
1571	node = mem->last_scanned_node;
1572
1573	node = next_node(node, mem->scan_nodes);
1574	if (node == MAX_NUMNODES)
1575		node = first_node(mem->scan_nodes);
1576	/*
1577	 * We call this when we hit limit, not when pages are added to LRU.
1578	 * No LRU may hold pages because all pages are UNEVICTABLE or
1579	 * memcg is too small and all pages are not on LRU. In that case,
1580	 * we use curret node.
1581	 */
1582	if (unlikely(node == MAX_NUMNODES))
1583		node = numa_node_id();
1584
1585	mem->last_scanned_node = node;
1586	return node;
1587}
1588
1589/*
1590 * Check all nodes whether it contains reclaimable pages or not.
1591 * For quick scan, we make use of scan_nodes. This will allow us to skip
1592 * unused nodes. But scan_nodes is lazily updated and may not cotain
1593 * enough new information. We need to do double check.
1594 */
1595bool mem_cgroup_reclaimable(struct mem_cgroup *mem, bool noswap)
1596{
1597	int nid;
1598
1599	/*
1600	 * quick check...making use of scan_node.
1601	 * We can skip unused nodes.
1602	 */
1603	if (!nodes_empty(mem->scan_nodes)) {
1604		for (nid = first_node(mem->scan_nodes);
1605		     nid < MAX_NUMNODES;
1606		     nid = next_node(nid, mem->scan_nodes)) {
1607
1608			if (test_mem_cgroup_node_reclaimable(mem, nid, noswap))
1609				return true;
1610		}
1611	}
1612	/*
1613	 * Check rest of nodes.
1614	 */
1615	for_each_node_state(nid, N_HIGH_MEMORY) {
1616		if (node_isset(nid, mem->scan_nodes))
1617			continue;
1618		if (test_mem_cgroup_node_reclaimable(mem, nid, noswap))
1619			return true;
1620	}
1621	return false;
1622}
1623
1624#else
1625int mem_cgroup_select_victim_node(struct mem_cgroup *mem)
1626{
1627	return 0;
1628}
1629
1630bool mem_cgroup_reclaimable(struct mem_cgroup *mem, bool noswap)
1631{
1632	return test_mem_cgroup_node_reclaimable(mem, 0, noswap);
1633}
1634#endif
1635
1636/*
1637 * Scan the hierarchy if needed to reclaim memory. We remember the last child
1638 * we reclaimed from, so that we don't end up penalizing one child extensively
1639 * based on its position in the children list.
1640 *
1641 * root_mem is the original ancestor that we've been reclaim from.
1642 *
1643 * We give up and return to the caller when we visit root_mem twice.
1644 * (other groups can be removed while we're walking....)
1645 *
1646 * If shrink==true, for avoiding to free too much, this returns immedieately.
1647 */
1648static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
1649						struct zone *zone,
1650						gfp_t gfp_mask,
1651						unsigned long reclaim_options,
1652						unsigned long *total_scanned)
1653{
1654	struct mem_cgroup *victim;
1655	int ret, total = 0;
1656	int loop = 0;
1657	bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
1658	bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
1659	bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
1660	unsigned long excess;
1661	unsigned long nr_scanned;
 
 
 
 
1662
1663	excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT;
1664
1665	/* If memsw_is_minimum==1, swap-out is of-no-use. */
1666	if (!check_soft && !shrink && root_mem->memsw_is_minimum)
1667		noswap = true;
1668
1669	while (1) {
1670		victim = mem_cgroup_select_victim(root_mem);
1671		if (victim == root_mem) {
1672			loop++;
1673			/*
1674			 * We are not draining per cpu cached charges during
1675			 * soft limit reclaim  because global reclaim doesn't
1676			 * care about charges. It tries to free some memory and
1677			 * charges will not give any.
1678			 */
1679			if (!check_soft && loop >= 1)
1680				drain_all_stock_async(root_mem);
1681			if (loop >= 2) {
1682				/*
1683				 * If we have not been able to reclaim
1684				 * anything, it might because there are
1685				 * no reclaimable pages under this hierarchy
1686				 */
1687				if (!check_soft || !total) {
1688					css_put(&victim->css);
1689					break;
1690				}
1691				/*
1692				 * We want to do more targeted reclaim.
1693				 * excess >> 2 is not to excessive so as to
1694				 * reclaim too much, nor too less that we keep
1695				 * coming back to reclaim from this cgroup
1696				 */
1697				if (total >= (excess >> 2) ||
1698					(loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) {
1699					css_put(&victim->css);
1700					break;
1701				}
1702			}
1703		}
1704		if (!mem_cgroup_reclaimable(victim, noswap)) {
1705			/* this cgroup's local usage == 0 */
1706			css_put(&victim->css);
1707			continue;
1708		}
1709		/* we use swappiness of local cgroup */
1710		if (check_soft) {
1711			ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
1712				noswap, zone, &nr_scanned);
1713			*total_scanned += nr_scanned;
1714		} else
1715			ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
1716						noswap);
1717		css_put(&victim->css);
1718		/*
1719		 * At shrinking usage, we can't check we should stop here or
1720		 * reclaim more. It's depends on callers. last_scanned_child
1721		 * will work enough for keeping fairness under tree.
1722		 */
1723		if (shrink)
1724			return ret;
1725		total += ret;
1726		if (check_soft) {
1727			if (!res_counter_soft_limit_excess(&root_mem->res))
1728				return total;
1729		} else if (mem_cgroup_margin(root_mem))
1730			return total;
1731	}
 
1732	return total;
1733}
1734
 
 
 
 
 
 
 
 
1735/*
1736 * Check OOM-Killer is already running under our hierarchy.
1737 * If someone is running, return false.
1738 * Has to be called with memcg_oom_lock
1739 */
1740static bool mem_cgroup_oom_lock(struct mem_cgroup *mem)
1741{
1742	struct mem_cgroup *iter, *failed = NULL;
1743	bool cond = true;
1744
1745	for_each_mem_cgroup_tree_cond(iter, mem, cond) {
 
 
1746		if (iter->oom_lock) {
1747			/*
1748			 * this subtree of our hierarchy is already locked
1749			 * so we cannot give a lock.
1750			 */
1751			failed = iter;
1752			cond = false;
 
1753		} else
1754			iter->oom_lock = true;
1755	}
1756
1757	if (!failed)
1758		return true;
1759
1760	/*
1761	 * OK, we failed to lock the whole subtree so we have to clean up
1762	 * what we set up to the failing subtree
1763	 */
1764	cond = true;
1765	for_each_mem_cgroup_tree_cond(iter, mem, cond) {
1766		if (iter == failed) {
1767			cond = false;
1768			continue;
1769		}
1770		iter->oom_lock = false;
1771	}
1772	return false;
 
 
 
1773}
1774
1775/*
1776 * Has to be called with memcg_oom_lock
1777 */
1778static int mem_cgroup_oom_unlock(struct mem_cgroup *mem)
1779{
1780	struct mem_cgroup *iter;
1781
1782	for_each_mem_cgroup_tree(iter, mem)
 
 
1783		iter->oom_lock = false;
1784	return 0;
1785}
1786
1787static void mem_cgroup_mark_under_oom(struct mem_cgroup *mem)
1788{
1789	struct mem_cgroup *iter;
1790
1791	for_each_mem_cgroup_tree(iter, mem)
1792		atomic_inc(&iter->under_oom);
 
 
1793}
1794
1795static void mem_cgroup_unmark_under_oom(struct mem_cgroup *mem)
1796{
1797	struct mem_cgroup *iter;
1798
1799	/*
1800	 * When a new child is created while the hierarchy is under oom,
1801	 * mem_cgroup_oom_lock() may not be called. We have to use
1802	 * atomic_add_unless() here.
1803	 */
1804	for_each_mem_cgroup_tree(iter, mem)
1805		atomic_add_unless(&iter->under_oom, -1, 0);
 
 
 
1806}
1807
1808static DEFINE_SPINLOCK(memcg_oom_lock);
1809static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1810
1811struct oom_wait_info {
1812	struct mem_cgroup *mem;
1813	wait_queue_t	wait;
1814};
1815
1816static int memcg_oom_wake_function(wait_queue_t *wait,
1817	unsigned mode, int sync, void *arg)
1818{
1819	struct mem_cgroup *wake_mem = (struct mem_cgroup *)arg,
1820			  *oom_wait_mem;
1821	struct oom_wait_info *oom_wait_info;
1822
1823	oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1824	oom_wait_mem = oom_wait_info->mem;
1825
1826	/*
1827	 * Both of oom_wait_info->mem and wake_mem are stable under us.
1828	 * Then we can use css_is_ancestor without taking care of RCU.
1829	 */
1830	if (!mem_cgroup_same_or_subtree(oom_wait_mem, wake_mem)
1831			&& !mem_cgroup_same_or_subtree(wake_mem, oom_wait_mem))
1832		return 0;
1833	return autoremove_wake_function(wait, mode, sync, arg);
1834}
1835
1836static void memcg_wakeup_oom(struct mem_cgroup *mem)
1837{
1838	/* for filtering, pass "mem" as argument. */
1839	__wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, mem);
 
 
 
 
 
 
 
 
1840}
1841
1842static void memcg_oom_recover(struct mem_cgroup *mem)
1843{
1844	if (mem && atomic_read(&mem->under_oom))
1845		memcg_wakeup_oom(mem);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1846}
1847
1848/*
1849 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1850 */
1851bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask)
1852{
 
1853	struct oom_wait_info owait;
1854	bool locked, need_to_kill;
 
 
 
 
1855
1856	owait.mem = mem;
 
 
 
1857	owait.wait.flags = 0;
1858	owait.wait.func = memcg_oom_wake_function;
1859	owait.wait.private = current;
1860	INIT_LIST_HEAD(&owait.wait.task_list);
1861	need_to_kill = true;
1862	mem_cgroup_mark_under_oom(mem);
1863
1864	/* At first, try to OOM lock hierarchy under mem.*/
1865	spin_lock(&memcg_oom_lock);
1866	locked = mem_cgroup_oom_lock(mem);
1867	/*
1868	 * Even if signal_pending(), we can't quit charge() loop without
1869	 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
1870	 * under OOM is always welcomed, use TASK_KILLABLE here.
1871	 */
1872	prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1873	if (!locked || mem->oom_kill_disable)
1874		need_to_kill = false;
 
 
1875	if (locked)
1876		mem_cgroup_oom_notify(mem);
1877	spin_unlock(&memcg_oom_lock);
1878
1879	if (need_to_kill) {
 
1880		finish_wait(&memcg_oom_waitq, &owait.wait);
1881		mem_cgroup_out_of_memory(mem, mask);
 
1882	} else {
1883		schedule();
 
1884		finish_wait(&memcg_oom_waitq, &owait.wait);
1885	}
1886	spin_lock(&memcg_oom_lock);
1887	if (locked)
1888		mem_cgroup_oom_unlock(mem);
1889	memcg_wakeup_oom(mem);
1890	spin_unlock(&memcg_oom_lock);
1891
1892	mem_cgroup_unmark_under_oom(mem);
1893
1894	if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current))
1895		return false;
1896	/* Give chance to dying process */
1897	schedule_timeout(1);
 
 
 
 
 
 
 
 
1898	return true;
1899}
1900
1901/*
1902 * Currently used to update mapped file statistics, but the routine can be
1903 * generalized to update other statistics as well.
1904 *
1905 * Notes: Race condition
1906 *
1907 * We usually use page_cgroup_lock() for accessing page_cgroup member but
1908 * it tends to be costly. But considering some conditions, we doesn't need
1909 * to do so _always_.
1910 *
1911 * Considering "charge", lock_page_cgroup() is not required because all
1912 * file-stat operations happen after a page is attached to radix-tree. There
1913 * are no race with "charge".
1914 *
1915 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
1916 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
1917 * if there are race with "uncharge". Statistics itself is properly handled
1918 * by flags.
1919 *
1920 * Considering "move", this is an only case we see a race. To make the race
1921 * small, we check MEM_CGROUP_ON_MOVE percpu value and detect there are
1922 * possibility of race condition. If there is, we take a lock.
1923 */
1924
1925void mem_cgroup_update_page_stat(struct page *page,
1926				 enum mem_cgroup_page_stat_item idx, int val)
1927{
1928	struct mem_cgroup *mem;
1929	struct page_cgroup *pc = lookup_page_cgroup(page);
1930	bool need_unlock = false;
1931	unsigned long uninitialized_var(flags);
1932
1933	if (unlikely(!pc))
 
 
 
 
 
 
 
 
 
 
 
1934		return;
1935
1936	rcu_read_lock();
1937	mem = pc->mem_cgroup;
1938	if (unlikely(!mem || !PageCgroupUsed(pc)))
1939		goto out;
1940	/* pc->mem_cgroup is unstable ? */
1941	if (unlikely(mem_cgroup_stealed(mem)) || PageTransHuge(page)) {
1942		/* take a lock against to access pc->mem_cgroup */
1943		move_lock_page_cgroup(pc, &flags);
1944		need_unlock = true;
1945		mem = pc->mem_cgroup;
1946		if (!mem || !PageCgroupUsed(pc))
1947			goto out;
1948	}
1949
1950	switch (idx) {
1951	case MEMCG_NR_FILE_MAPPED:
1952		if (val > 0)
1953			SetPageCgroupFileMapped(pc);
1954		else if (!page_mapped(page))
1955			ClearPageCgroupFileMapped(pc);
1956		idx = MEM_CGROUP_STAT_FILE_MAPPED;
1957		break;
1958	default:
1959		BUG();
1960	}
1961
1962	this_cpu_add(mem->stat->count[idx], val);
 
 
 
 
 
 
1963
1964out:
1965	if (unlikely(need_unlock))
1966		move_unlock_page_cgroup(pc, &flags);
1967	rcu_read_unlock();
1968	return;
1969}
1970EXPORT_SYMBOL(mem_cgroup_update_page_stat);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1971
1972/*
1973 * size of first charge trial. "32" comes from vmscan.c's magic value.
1974 * TODO: maybe necessary to use big numbers in big irons.
1975 */
1976#define CHARGE_BATCH	32U
1977struct memcg_stock_pcp {
1978	struct mem_cgroup *cached; /* this never be root cgroup */
1979	unsigned int nr_pages;
1980	struct work_struct work;
1981	unsigned long flags;
1982#define FLUSHING_CACHED_CHARGE	(0)
1983};
1984static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
1985static DEFINE_MUTEX(percpu_charge_mutex);
1986
1987/*
1988 * Try to consume stocked charge on this cpu. If success, one page is consumed
1989 * from local stock and true is returned. If the stock is 0 or charges from a
1990 * cgroup which is not current target, returns false. This stock will be
1991 * refilled.
 
 
 
 
 
1992 */
1993static bool consume_stock(struct mem_cgroup *mem)
1994{
1995	struct memcg_stock_pcp *stock;
1996	bool ret = true;
 
 
 
1997
1998	stock = &get_cpu_var(memcg_stock);
1999	if (mem == stock->cached && stock->nr_pages)
2000		stock->nr_pages--;
2001	else /* need to call res_counter_charge */
2002		ret = false;
2003	put_cpu_var(memcg_stock);
2004	return ret;
2005}
2006
2007/*
2008 * Returns stocks cached in percpu to res_counter and reset cached information.
2009 */
2010static void drain_stock(struct memcg_stock_pcp *stock)
2011{
2012	struct mem_cgroup *old = stock->cached;
2013
2014	if (stock->nr_pages) {
2015		unsigned long bytes = stock->nr_pages * PAGE_SIZE;
2016
2017		res_counter_uncharge(&old->res, bytes);
2018		if (do_swap_account)
2019			res_counter_uncharge(&old->memsw, bytes);
2020		stock->nr_pages = 0;
2021	}
2022	stock->cached = NULL;
2023}
2024
2025/*
2026 * This must be called under preempt disabled or must be called by
2027 * a thread which is pinned to local cpu.
2028 */
2029static void drain_local_stock(struct work_struct *dummy)
2030{
2031	struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock);
2032	drain_stock(stock);
2033	clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2034}
2035
2036/*
2037 * Cache charges(val) which is from res_counter, to local per_cpu area.
2038 * This will be consumed by consume_stock() function, later.
2039 */
2040static void refill_stock(struct mem_cgroup *mem, unsigned int nr_pages)
2041{
2042	struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
2043
2044	if (stock->cached != mem) { /* reset if necessary */
2045		drain_stock(stock);
2046		stock->cached = mem;
2047	}
2048	stock->nr_pages += nr_pages;
2049	put_cpu_var(memcg_stock);
2050}
2051
2052/*
2053 * Drains all per-CPU charge caches for given root_mem resp. subtree
2054 * of the hierarchy under it. sync flag says whether we should block
2055 * until the work is done.
2056 */
2057static void drain_all_stock(struct mem_cgroup *root_mem, bool sync)
2058{
2059	int cpu, curcpu;
2060
 
 
 
2061	/* Notify other cpus that system-wide "drain" is running */
2062	get_online_cpus();
2063	curcpu = get_cpu();
2064	for_each_online_cpu(cpu) {
2065		struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2066		struct mem_cgroup *mem;
2067
2068		mem = stock->cached;
2069		if (!mem || !stock->nr_pages)
2070			continue;
2071		if (!mem_cgroup_same_or_subtree(root_mem, mem))
2072			continue;
2073		if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2074			if (cpu == curcpu)
2075				drain_local_stock(&stock->work);
2076			else
2077				schedule_work_on(cpu, &stock->work);
2078		}
2079	}
2080	put_cpu();
 
 
 
2081
2082	if (!sync)
2083		goto out;
 
 
 
 
2084
2085	for_each_online_cpu(cpu) {
2086		struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2087		if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
2088			flush_work(&stock->work);
2089	}
2090out:
2091 	put_online_cpus();
 
 
2092}
2093
2094/*
2095 * Tries to drain stocked charges in other cpus. This function is asynchronous
2096 * and just put a work per cpu for draining localy on each cpu. Caller can
2097 * expects some charges will be back to res_counter later but cannot wait for
2098 * it.
2099 */
2100static void drain_all_stock_async(struct mem_cgroup *root_mem)
2101{
2102	/*
2103	 * If someone calls draining, avoid adding more kworker runs.
2104	 */
2105	if (!mutex_trylock(&percpu_charge_mutex))
2106		return;
2107	drain_all_stock(root_mem, false);
2108	mutex_unlock(&percpu_charge_mutex);
2109}
2110
2111/* This is a synchronous drain interface. */
2112static void drain_all_stock_sync(struct mem_cgroup *root_mem)
2113{
2114	/* called when force_empty is called */
2115	mutex_lock(&percpu_charge_mutex);
2116	drain_all_stock(root_mem, true);
2117	mutex_unlock(&percpu_charge_mutex);
2118}
2119
2120/*
2121 * This function drains percpu counter value from DEAD cpu and
2122 * move it to local cpu. Note that this function can be preempted.
2123 */
2124static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *mem, int cpu)
2125{
2126	int i;
2127
2128	spin_lock(&mem->pcp_counter_lock);
2129	for (i = 0; i < MEM_CGROUP_STAT_DATA; i++) {
2130		long x = per_cpu(mem->stat->count[i], cpu);
2131
2132		per_cpu(mem->stat->count[i], cpu) = 0;
2133		mem->nocpu_base.count[i] += x;
2134	}
2135	for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
2136		unsigned long x = per_cpu(mem->stat->events[i], cpu);
2137
2138		per_cpu(mem->stat->events[i], cpu) = 0;
2139		mem->nocpu_base.events[i] += x;
2140	}
2141	/* need to clear ON_MOVE value, works as a kind of lock. */
2142	per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) = 0;
2143	spin_unlock(&mem->pcp_counter_lock);
2144}
2145
2146static void synchronize_mem_cgroup_on_move(struct mem_cgroup *mem, int cpu)
 
2147{
2148	int idx = MEM_CGROUP_ON_MOVE;
2149
2150	spin_lock(&mem->pcp_counter_lock);
2151	per_cpu(mem->stat->count[idx], cpu) = mem->nocpu_base.count[idx];
2152	spin_unlock(&mem->pcp_counter_lock);
2153}
 
2154
2155static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
2156					unsigned long action,
2157					void *hcpu)
2158{
2159	int cpu = (unsigned long)hcpu;
2160	struct memcg_stock_pcp *stock;
2161	struct mem_cgroup *iter;
2162
2163	if ((action == CPU_ONLINE)) {
2164		for_each_mem_cgroup_all(iter)
2165			synchronize_mem_cgroup_on_move(iter, cpu);
2166		return NOTIFY_OK;
 
 
 
 
 
 
2167	}
2168
2169	if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN)
2170		return NOTIFY_OK;
2171
2172	for_each_mem_cgroup_all(iter)
2173		mem_cgroup_drain_pcp_counter(iter, cpu);
2174
2175	stock = &per_cpu(memcg_stock, cpu);
2176	drain_stock(stock);
2177	return NOTIFY_OK;
2178}
2179
 
 
 
 
 
 
 
 
 
 
 
 
 
2180
2181/* See __mem_cgroup_try_charge() for details */
2182enum {
2183	CHARGE_OK,		/* success */
2184	CHARGE_RETRY,		/* need to retry but retry is not bad */
2185	CHARGE_NOMEM,		/* we can't do more. return -ENOMEM */
2186	CHARGE_WOULDBLOCK,	/* GFP_WAIT wasn't set and no enough res. */
2187	CHARGE_OOM_DIE,		/* the current is killed because of OOM */
2188};
2189
2190static int mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask,
2191				unsigned int nr_pages, bool oom_check)
2192{
2193	unsigned long csize = nr_pages * PAGE_SIZE;
2194	struct mem_cgroup *mem_over_limit;
2195	struct res_counter *fail_res;
2196	unsigned long flags = 0;
2197	int ret;
2198
2199	ret = res_counter_charge(&mem->res, csize, &fail_res);
 
2200
2201	if (likely(!ret)) {
2202		if (!do_swap_account)
2203			return CHARGE_OK;
2204		ret = res_counter_charge(&mem->memsw, csize, &fail_res);
2205		if (likely(!ret))
2206			return CHARGE_OK;
2207
2208		res_counter_uncharge(&mem->res, csize);
2209		mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
2210		flags |= MEM_CGROUP_RECLAIM_NOSWAP;
2211	} else
2212		mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
2213	/*
2214	 * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch
2215	 * of regular pages (CHARGE_BATCH), or a single regular page (1).
2216	 *
2217	 * Never reclaim on behalf of optional batching, retry with a
2218	 * single page instead.
2219	 */
2220	if (nr_pages == CHARGE_BATCH)
2221		return CHARGE_RETRY;
2222
2223	if (!(gfp_mask & __GFP_WAIT))
2224		return CHARGE_WOULDBLOCK;
 
 
 
2225
2226	ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
2227					      gfp_mask, flags, NULL);
2228	if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2229		return CHARGE_RETRY;
2230	/*
2231	 * Even though the limit is exceeded at this point, reclaim
2232	 * may have been able to free some pages.  Retry the charge
2233	 * before killing the task.
2234	 *
2235	 * Only for regular pages, though: huge pages are rather
2236	 * unlikely to succeed so close to the limit, and we fall back
2237	 * to regular pages anyway in case of failure.
2238	 */
2239	if (nr_pages == 1 && ret)
2240		return CHARGE_RETRY;
2241
2242	/*
2243	 * At task move, charge accounts can be doubly counted. So, it's
2244	 * better to wait until the end of task_move if something is going on.
2245	 */
2246	if (mem_cgroup_wait_acct_move(mem_over_limit))
2247		return CHARGE_RETRY;
2248
2249	/* If we don't need to call oom-killer at el, return immediately */
2250	if (!oom_check)
2251		return CHARGE_NOMEM;
2252	/* check OOM */
2253	if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask))
2254		return CHARGE_OOM_DIE;
2255
2256	return CHARGE_RETRY;
2257}
2258
2259/*
2260 * Unlike exported interface, "oom" parameter is added. if oom==true,
2261 * oom-killer can be invoked.
2262 */
2263static int __mem_cgroup_try_charge(struct mm_struct *mm,
2264				   gfp_t gfp_mask,
2265				   unsigned int nr_pages,
2266				   struct mem_cgroup **memcg,
2267				   bool oom)
2268{
2269	unsigned int batch = max(CHARGE_BATCH, nr_pages);
2270	int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2271	struct mem_cgroup *mem = NULL;
2272	int ret;
2273
2274	/*
2275	 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
2276	 * in system level. So, allow to go ahead dying process in addition to
2277	 * MEMDIE process.
2278	 */
2279	if (unlikely(test_thread_flag(TIF_MEMDIE)
2280		     || fatal_signal_pending(current)))
2281		goto bypass;
2282
2283	/*
2284	 * We always charge the cgroup the mm_struct belongs to.
2285	 * The mm_struct's mem_cgroup changes on task migration if the
2286	 * thread group leader migrates. It's possible that mm is not
2287	 * set, if so charge the init_mm (happens for pagecache usage).
2288	 */
2289	if (!*memcg && !mm)
2290		goto bypass;
2291again:
2292	if (*memcg) { /* css should be a valid one */
2293		mem = *memcg;
2294		VM_BUG_ON(css_is_removed(&mem->css));
2295		if (mem_cgroup_is_root(mem))
2296			goto done;
2297		if (nr_pages == 1 && consume_stock(mem))
2298			goto done;
2299		css_get(&mem->css);
2300	} else {
2301		struct task_struct *p;
2302
2303		rcu_read_lock();
2304		p = rcu_dereference(mm->owner);
2305		/*
2306		 * Because we don't have task_lock(), "p" can exit.
2307		 * In that case, "mem" can point to root or p can be NULL with
2308		 * race with swapoff. Then, we have small risk of mis-accouning.
2309		 * But such kind of mis-account by race always happens because
2310		 * we don't have cgroup_mutex(). It's overkill and we allo that
2311		 * small race, here.
2312		 * (*) swapoff at el will charge against mm-struct not against
2313		 * task-struct. So, mm->owner can be NULL.
2314		 */
2315		mem = mem_cgroup_from_task(p);
2316		if (!mem || mem_cgroup_is_root(mem)) {
2317			rcu_read_unlock();
2318			goto done;
2319		}
2320		if (nr_pages == 1 && consume_stock(mem)) {
2321			/*
2322			 * It seems dagerous to access memcg without css_get().
2323			 * But considering how consume_stok works, it's not
2324			 * necessary. If consume_stock success, some charges
2325			 * from this memcg are cached on this cpu. So, we
2326			 * don't need to call css_get()/css_tryget() before
2327			 * calling consume_stock().
2328			 */
2329			rcu_read_unlock();
2330			goto done;
2331		}
2332		/* after here, we may be blocked. we need to get refcnt */
2333		if (!css_tryget(&mem->css)) {
2334			rcu_read_unlock();
2335			goto again;
2336		}
2337		rcu_read_unlock();
2338	}
2339
2340	do {
2341		bool oom_check;
 
 
 
 
 
 
 
 
 
 
 
 
 
2342
2343		/* If killed, bypass charge */
2344		if (fatal_signal_pending(current)) {
2345			css_put(&mem->css);
2346			goto bypass;
2347		}
2348
2349		oom_check = false;
2350		if (oom && !nr_oom_retries) {
2351			oom_check = true;
2352			nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2353		}
2354
2355		ret = mem_cgroup_do_charge(mem, gfp_mask, batch, oom_check);
2356		switch (ret) {
2357		case CHARGE_OK:
2358			break;
2359		case CHARGE_RETRY: /* not in OOM situation but retry */
2360			batch = nr_pages;
2361			css_put(&mem->css);
2362			mem = NULL;
2363			goto again;
2364		case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
2365			css_put(&mem->css);
2366			goto nomem;
2367		case CHARGE_NOMEM: /* OOM routine works */
2368			if (!oom) {
2369				css_put(&mem->css);
2370				goto nomem;
2371			}
2372			/* If oom, we never return -ENOMEM */
2373			nr_oom_retries--;
2374			break;
2375		case CHARGE_OOM_DIE: /* Killed by OOM Killer */
2376			css_put(&mem->css);
2377			goto bypass;
2378		}
2379	} while (ret != CHARGE_OK);
2380
2381	if (batch > nr_pages)
2382		refill_stock(mem, batch - nr_pages);
2383	css_put(&mem->css);
2384done:
2385	*memcg = mem;
2386	return 0;
2387nomem:
2388	*memcg = NULL;
2389	return -ENOMEM;
2390bypass:
2391	*memcg = NULL;
2392	return 0;
2393}
2394
2395/*
2396 * Somemtimes we have to undo a charge we got by try_charge().
2397 * This function is for that and do uncharge, put css's refcnt.
2398 * gotten by try_charge().
2399 */
2400static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem,
2401				       unsigned int nr_pages)
2402{
2403	if (!mem_cgroup_is_root(mem)) {
2404		unsigned long bytes = nr_pages * PAGE_SIZE;
2405
2406		res_counter_uncharge(&mem->res, bytes);
2407		if (do_swap_account)
2408			res_counter_uncharge(&mem->memsw, bytes);
2409	}
2410}
2411
2412/*
2413 * A helper function to get mem_cgroup from ID. must be called under
2414 * rcu_read_lock(). The caller must check css_is_removed() or some if
2415 * it's concern. (dropping refcnt from swap can be called against removed
2416 * memcg.)
2417 */
2418static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2419{
2420	struct cgroup_subsys_state *css;
2421
2422	/* ID 0 is unused ID */
2423	if (!id)
2424		return NULL;
2425	css = css_lookup(&mem_cgroup_subsys, id);
2426	if (!css)
2427		return NULL;
2428	return container_of(css, struct mem_cgroup, css);
2429}
2430
2431struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2432{
2433	struct mem_cgroup *mem = NULL;
2434	struct page_cgroup *pc;
2435	unsigned short id;
2436	swp_entry_t ent;
2437
2438	VM_BUG_ON(!PageLocked(page));
 
 
2439
2440	pc = lookup_page_cgroup(page);
2441	lock_page_cgroup(pc);
2442	if (PageCgroupUsed(pc)) {
2443		mem = pc->mem_cgroup;
2444		if (mem && !css_tryget(&mem->css))
2445			mem = NULL;
2446	} else if (PageSwapCache(page)) {
2447		ent.val = page_private(page);
2448		id = lookup_swap_cgroup(ent);
2449		rcu_read_lock();
2450		mem = mem_cgroup_lookup(id);
2451		if (mem && !css_tryget(&mem->css))
2452			mem = NULL;
2453		rcu_read_unlock();
2454	}
2455	unlock_page_cgroup(pc);
2456	return mem;
2457}
2458
2459static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
2460				       struct page *page,
2461				       unsigned int nr_pages,
2462				       struct page_cgroup *pc,
2463				       enum charge_type ctype)
2464{
2465	lock_page_cgroup(pc);
2466	if (unlikely(PageCgroupUsed(pc))) {
2467		unlock_page_cgroup(pc);
2468		__mem_cgroup_cancel_charge(mem, nr_pages);
2469		return;
2470	}
2471	/*
2472	 * we don't need page_cgroup_lock about tail pages, becase they are not
2473	 * accessed by any other context at this point.
2474	 */
2475	pc->mem_cgroup = mem;
2476	/*
2477	 * We access a page_cgroup asynchronously without lock_page_cgroup().
2478	 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2479	 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2480	 * before USED bit, we need memory barrier here.
2481	 * See mem_cgroup_add_lru_list(), etc.
2482 	 */
2483	smp_wmb();
2484	switch (ctype) {
2485	case MEM_CGROUP_CHARGE_TYPE_CACHE:
2486	case MEM_CGROUP_CHARGE_TYPE_SHMEM:
2487		SetPageCgroupCache(pc);
2488		SetPageCgroupUsed(pc);
2489		break;
2490	case MEM_CGROUP_CHARGE_TYPE_MAPPED:
2491		ClearPageCgroupCache(pc);
2492		SetPageCgroupUsed(pc);
2493		break;
2494	default:
2495		break;
2496	}
2497
2498	mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), nr_pages);
2499	unlock_page_cgroup(pc);
2500	/*
2501	 * "charge_statistics" updated event counter. Then, check it.
2502	 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2503	 * if they exceeds softlimit.
2504	 */
2505	memcg_check_events(mem, page);
 
 
2506}
2507
2508#ifdef CONFIG_TRANSPARENT_HUGEPAGE
2509
2510#define PCGF_NOCOPY_AT_SPLIT ((1 << PCG_LOCK) | (1 << PCG_MOVE_LOCK) |\
2511			(1 << PCG_ACCT_LRU) | (1 << PCG_MIGRATION))
2512/*
2513 * Because tail pages are not marked as "used", set it. We're under
2514 * zone->lru_lock, 'splitting on pmd' and compund_lock.
2515 */
2516void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail)
2517{
2518	struct page_cgroup *head_pc = lookup_page_cgroup(head);
2519	struct page_cgroup *tail_pc = lookup_page_cgroup(tail);
2520	unsigned long flags;
2521
2522	if (mem_cgroup_disabled())
2523		return;
2524	/*
2525	 * We have no races with charge/uncharge but will have races with
2526	 * page state accounting.
2527	 */
2528	move_lock_page_cgroup(head_pc, &flags);
2529
2530	tail_pc->mem_cgroup = head_pc->mem_cgroup;
2531	smp_wmb(); /* see __commit_charge() */
2532	if (PageCgroupAcctLRU(head_pc)) {
2533		enum lru_list lru;
2534		struct mem_cgroup_per_zone *mz;
2535
2536		/*
2537		 * LRU flags cannot be copied because we need to add tail
2538		 *.page to LRU by generic call and our hook will be called.
2539		 * We hold lru_lock, then, reduce counter directly.
2540		 */
2541		lru = page_lru(head);
2542		mz = page_cgroup_zoneinfo(head_pc->mem_cgroup, head);
2543		MEM_CGROUP_ZSTAT(mz, lru) -= 1;
2544	}
2545	tail_pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
2546	move_unlock_page_cgroup(head_pc, &flags);
2547}
2548#endif
2549
2550/**
2551 * mem_cgroup_move_account - move account of the page
2552 * @page: the page
2553 * @nr_pages: number of regular pages (>1 for huge pages)
2554 * @pc:	page_cgroup of the page.
2555 * @from: mem_cgroup which the page is moved from.
2556 * @to:	mem_cgroup which the page is moved to. @from != @to.
2557 * @uncharge: whether we should call uncharge and css_put against @from.
2558 *
2559 * The caller must confirm following.
2560 * - page is not on LRU (isolate_page() is useful.)
2561 * - compound_lock is held when nr_pages > 1
2562 *
2563 * This function doesn't do "charge" nor css_get to new cgroup. It should be
2564 * done by a caller(__mem_cgroup_try_charge would be useful). If @uncharge is
2565 * true, this function does "uncharge" from old cgroup, but it doesn't if
2566 * @uncharge is false, so a caller should do "uncharge".
2567 */
2568static int mem_cgroup_move_account(struct page *page,
2569				   unsigned int nr_pages,
2570				   struct page_cgroup *pc,
2571				   struct mem_cgroup *from,
2572				   struct mem_cgroup *to,
2573				   bool uncharge)
2574{
2575	unsigned long flags;
2576	int ret;
2577
2578	VM_BUG_ON(from == to);
2579	VM_BUG_ON(PageLRU(page));
2580	/*
2581	 * The page is isolated from LRU. So, collapse function
2582	 * will not handle this page. But page splitting can happen.
2583	 * Do this check under compound_page_lock(). The caller should
2584	 * hold it.
2585	 */
2586	ret = -EBUSY;
2587	if (nr_pages > 1 && !PageTransHuge(page))
2588		goto out;
2589
2590	lock_page_cgroup(pc);
2591
2592	ret = -EINVAL;
2593	if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
2594		goto unlock;
2595
2596	move_lock_page_cgroup(pc, &flags);
2597
2598	if (PageCgroupFileMapped(pc)) {
2599		/* Update mapped_file data for mem_cgroup */
2600		preempt_disable();
2601		__this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2602		__this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2603		preempt_enable();
2604	}
2605	mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages);
2606	if (uncharge)
2607		/* This is not "cancel", but cancel_charge does all we need. */
2608		__mem_cgroup_cancel_charge(from, nr_pages);
2609
2610	/* caller should have done css_get */
2611	pc->mem_cgroup = to;
2612	mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages);
2613	/*
2614	 * We charges against "to" which may not have any tasks. Then, "to"
2615	 * can be under rmdir(). But in current implementation, caller of
2616	 * this function is just force_empty() and move charge, so it's
2617	 * guaranteed that "to" is never removed. So, we don't check rmdir
2618	 * status here.
2619	 */
2620	move_unlock_page_cgroup(pc, &flags);
2621	ret = 0;
2622unlock:
2623	unlock_page_cgroup(pc);
2624	/*
2625	 * check events
 
 
 
 
 
 
 
 
 
 
 
2626	 */
2627	memcg_check_events(to, page);
2628	memcg_check_events(from, page);
2629out:
2630	return ret;
2631}
2632
2633/*
2634 * move charges to its parent.
2635 */
2636
2637static int mem_cgroup_move_parent(struct page *page,
2638				  struct page_cgroup *pc,
2639				  struct mem_cgroup *child,
2640				  gfp_t gfp_mask)
2641{
2642	struct cgroup *cg = child->css.cgroup;
2643	struct cgroup *pcg = cg->parent;
2644	struct mem_cgroup *parent;
2645	unsigned int nr_pages;
2646	unsigned long uninitialized_var(flags);
2647	int ret;
2648
2649	/* Is ROOT ? */
2650	if (!pcg)
2651		return -EINVAL;
2652
2653	ret = -EBUSY;
2654	if (!get_page_unless_zero(page))
2655		goto out;
2656	if (isolate_lru_page(page))
2657		goto put;
2658
2659	nr_pages = hpage_nr_pages(page);
 
 
 
2660
2661	parent = mem_cgroup_from_cont(pcg);
2662	ret = __mem_cgroup_try_charge(NULL, gfp_mask, nr_pages, &parent, false);
2663	if (ret || !parent)
2664		goto put_back;
2665
2666	if (nr_pages > 1)
2667		flags = compound_lock_irqsave(page);
 
 
 
2668
2669	ret = mem_cgroup_move_account(page, nr_pages, pc, child, parent, true);
2670	if (ret)
2671		__mem_cgroup_cancel_charge(parent, nr_pages);
 
 
2672
2673	if (nr_pages > 1)
2674		compound_unlock_irqrestore(page, flags);
2675put_back:
2676	putback_lru_page(page);
2677put:
2678	put_page(page);
2679out:
2680	return ret;
2681}
2682
2683/*
2684 * Charge the memory controller for page usage.
2685 * Return
2686 * 0 if the charge was successful
2687 * < 0 if the cgroup is over its limit
2688 */
2689static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
2690				gfp_t gfp_mask, enum charge_type ctype)
2691{
2692	struct mem_cgroup *mem = NULL;
2693	unsigned int nr_pages = 1;
2694	struct page_cgroup *pc;
2695	bool oom = true;
2696	int ret;
2697
2698	if (PageTransHuge(page)) {
2699		nr_pages <<= compound_order(page);
2700		VM_BUG_ON(!PageTransHuge(page));
2701		/*
2702		 * Never OOM-kill a process for a huge page.  The
2703		 * fault handler will fall back to regular pages.
2704		 */
2705		oom = false;
2706	}
2707
2708	pc = lookup_page_cgroup(page);
2709	BUG_ON(!pc); /* XXX: remove this and move pc lookup into commit */
2710
2711	ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &mem, oom);
2712	if (ret || !mem)
2713		return ret;
2714
2715	__mem_cgroup_commit_charge(mem, page, nr_pages, pc, ctype);
2716	return 0;
2717}
2718
2719int mem_cgroup_newpage_charge(struct page *page,
2720			      struct mm_struct *mm, gfp_t gfp_mask)
2721{
2722	if (mem_cgroup_disabled())
2723		return 0;
2724	/*
2725	 * If already mapped, we don't have to account.
2726	 * If page cache, page->mapping has address_space.
2727	 * But page->mapping may have out-of-use anon_vma pointer,
2728	 * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
2729	 * is NULL.
2730  	 */
2731	if (page_mapped(page) || (page->mapping && !PageAnon(page)))
2732		return 0;
2733	if (unlikely(!mm))
2734		mm = &init_mm;
2735	return mem_cgroup_charge_common(page, mm, gfp_mask,
2736				MEM_CGROUP_CHARGE_TYPE_MAPPED);
2737}
2738
2739static void
2740__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
2741					enum charge_type ctype);
2742
2743static void
2744__mem_cgroup_commit_charge_lrucare(struct page *page, struct mem_cgroup *mem,
2745					enum charge_type ctype)
2746{
2747	struct page_cgroup *pc = lookup_page_cgroup(page);
2748	/*
2749	 * In some case, SwapCache, FUSE(splice_buf->radixtree), the page
2750	 * is already on LRU. It means the page may on some other page_cgroup's
2751	 * LRU. Take care of it.
2752	 */
2753	mem_cgroup_lru_del_before_commit(page);
2754	__mem_cgroup_commit_charge(mem, page, 1, pc, ctype);
2755	mem_cgroup_lru_add_after_commit(page);
2756	return;
2757}
2758
2759int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
2760				gfp_t gfp_mask)
2761{
2762	struct mem_cgroup *mem = NULL;
2763	int ret;
2764
2765	if (mem_cgroup_disabled())
2766		return 0;
2767	if (PageCompound(page))
2768		return 0;
2769
2770	if (unlikely(!mm))
2771		mm = &init_mm;
2772
2773	if (page_is_file_cache(page)) {
2774		ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, &mem, true);
2775		if (ret || !mem)
2776			return ret;
2777
2778		/*
2779		 * FUSE reuses pages without going through the final
2780		 * put that would remove them from the LRU list, make
2781		 * sure that they get relinked properly.
2782		 */
2783		__mem_cgroup_commit_charge_lrucare(page, mem,
2784					MEM_CGROUP_CHARGE_TYPE_CACHE);
2785		return ret;
2786	}
2787	/* shmem */
2788	if (PageSwapCache(page)) {
2789		ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
2790		if (!ret)
2791			__mem_cgroup_commit_charge_swapin(page, mem,
2792					MEM_CGROUP_CHARGE_TYPE_SHMEM);
2793	} else
2794		ret = mem_cgroup_charge_common(page, mm, gfp_mask,
2795					MEM_CGROUP_CHARGE_TYPE_SHMEM);
2796
2797	return ret;
 
2798}
2799
2800/*
2801 * While swap-in, try_charge -> commit or cancel, the page is locked.
2802 * And when try_charge() successfully returns, one refcnt to memcg without
2803 * struct page_cgroup is acquired. This refcnt will be consumed by
2804 * "commit()" or removed by "cancel()"
2805 */
2806int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
2807				 struct page *page,
2808				 gfp_t mask, struct mem_cgroup **ptr)
2809{
2810	struct mem_cgroup *mem;
2811	int ret;
2812
2813	*ptr = NULL;
2814
2815	if (mem_cgroup_disabled())
2816		return 0;
2817
2818	if (!do_swap_account)
2819		goto charge_cur_mm;
2820	/*
2821	 * A racing thread's fault, or swapoff, may have already updated
2822	 * the pte, and even removed page from swap cache: in those cases
2823	 * do_swap_page()'s pte_same() test will fail; but there's also a
2824	 * KSM case which does need to charge the page.
2825	 */
2826	if (!PageSwapCache(page))
2827		goto charge_cur_mm;
2828	mem = try_get_mem_cgroup_from_page(page);
2829	if (!mem)
2830		goto charge_cur_mm;
2831	*ptr = mem;
2832	ret = __mem_cgroup_try_charge(NULL, mask, 1, ptr, true);
2833	css_put(&mem->css);
2834	return ret;
2835charge_cur_mm:
2836	if (unlikely(!mm))
2837		mm = &init_mm;
2838	return __mem_cgroup_try_charge(mm, mask, 1, ptr, true);
2839}
2840
2841static void
2842__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
2843					enum charge_type ctype)
2844{
2845	if (mem_cgroup_disabled())
2846		return;
2847	if (!ptr)
2848		return;
2849	cgroup_exclude_rmdir(&ptr->css);
2850
2851	__mem_cgroup_commit_charge_lrucare(page, ptr, ctype);
2852	/*
2853	 * Now swap is on-memory. This means this page may be
2854	 * counted both as mem and swap....double count.
2855	 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
2856	 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
2857	 * may call delete_from_swap_cache() before reach here.
2858	 */
2859	if (do_swap_account && PageSwapCache(page)) {
2860		swp_entry_t ent = {.val = page_private(page)};
2861		unsigned short id;
2862		struct mem_cgroup *memcg;
2863
2864		id = swap_cgroup_record(ent, 0);
2865		rcu_read_lock();
2866		memcg = mem_cgroup_lookup(id);
2867		if (memcg) {
2868			/*
2869			 * This recorded memcg can be obsolete one. So, avoid
2870			 * calling css_tryget
2871			 */
2872			if (!mem_cgroup_is_root(memcg))
2873				res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
2874			mem_cgroup_swap_statistics(memcg, false);
2875			mem_cgroup_put(memcg);
2876		}
2877		rcu_read_unlock();
2878	}
2879	/*
2880	 * At swapin, we may charge account against cgroup which has no tasks.
2881	 * So, rmdir()->pre_destroy() can be called while we do this charge.
2882	 * In that case, we need to call pre_destroy() again. check it here.
2883	 */
2884	cgroup_release_and_wakeup_rmdir(&ptr->css);
2885}
2886
2887void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
2888{
2889	__mem_cgroup_commit_charge_swapin(page, ptr,
2890					MEM_CGROUP_CHARGE_TYPE_MAPPED);
2891}
2892
2893void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
2894{
2895	if (mem_cgroup_disabled())
2896		return;
2897	if (!mem)
2898		return;
2899	__mem_cgroup_cancel_charge(mem, 1);
2900}
2901
2902static void mem_cgroup_do_uncharge(struct mem_cgroup *mem,
2903				   unsigned int nr_pages,
2904				   const enum charge_type ctype)
2905{
2906	struct memcg_batch_info *batch = NULL;
2907	bool uncharge_memsw = true;
2908
2909	/* If swapout, usage of swap doesn't decrease */
2910	if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
2911		uncharge_memsw = false;
2912
2913	batch = &current->memcg_batch;
2914	/*
2915	 * In usual, we do css_get() when we remember memcg pointer.
2916	 * But in this case, we keep res->usage until end of a series of
2917	 * uncharges. Then, it's ok to ignore memcg's refcnt.
2918	 */
2919	if (!batch->memcg)
2920		batch->memcg = mem;
2921	/*
2922	 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
2923	 * In those cases, all pages freed continuously can be expected to be in
2924	 * the same cgroup and we have chance to coalesce uncharges.
2925	 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
2926	 * because we want to do uncharge as soon as possible.
2927	 */
2928
2929	if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
2930		goto direct_uncharge;
2931
2932	if (nr_pages > 1)
2933		goto direct_uncharge;
2934
2935	/*
2936	 * In typical case, batch->memcg == mem. This means we can
2937	 * merge a series of uncharges to an uncharge of res_counter.
2938	 * If not, we uncharge res_counter ony by one.
 
 
 
 
 
 
2939	 */
2940	if (batch->memcg != mem)
2941		goto direct_uncharge;
2942	/* remember freed charge and uncharge it later */
2943	batch->nr_pages++;
2944	if (uncharge_memsw)
2945		batch->memsw_nr_pages++;
2946	return;
2947direct_uncharge:
2948	res_counter_uncharge(&mem->res, nr_pages * PAGE_SIZE);
2949	if (uncharge_memsw)
2950		res_counter_uncharge(&mem->memsw, nr_pages * PAGE_SIZE);
2951	if (unlikely(batch->memcg != mem))
2952		memcg_oom_recover(mem);
2953	return;
2954}
2955
2956/*
2957 * uncharge if !page_mapped(page)
 
 
 
 
 
 
 
 
 
 
2958 */
2959static struct mem_cgroup *
2960__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
2961{
2962	struct mem_cgroup *mem = NULL;
2963	unsigned int nr_pages = 1;
2964	struct page_cgroup *pc;
2965
2966	if (mem_cgroup_disabled())
2967		return NULL;
2968
2969	if (PageSwapCache(page))
2970		return NULL;
2971
2972	if (PageTransHuge(page)) {
2973		nr_pages <<= compound_order(page);
2974		VM_BUG_ON(!PageTransHuge(page));
2975	}
2976	/*
2977	 * Check if our page_cgroup is valid
2978	 */
2979	pc = lookup_page_cgroup(page);
2980	if (unlikely(!pc || !PageCgroupUsed(pc)))
2981		return NULL;
2982
2983	lock_page_cgroup(pc);
2984
2985	mem = pc->mem_cgroup;
 
2986
2987	if (!PageCgroupUsed(pc))
2988		goto unlock_out;
2989
2990	switch (ctype) {
2991	case MEM_CGROUP_CHARGE_TYPE_MAPPED:
2992	case MEM_CGROUP_CHARGE_TYPE_DROP:
2993		/* See mem_cgroup_prepare_migration() */
2994		if (page_mapped(page) || PageCgroupMigration(pc))
2995			goto unlock_out;
2996		break;
2997	case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
2998		if (!PageAnon(page)) {	/* Shared memory */
2999			if (page->mapping && !page_is_file_cache(page))
3000				goto unlock_out;
3001		} else if (page_mapped(page)) /* Anon */
3002				goto unlock_out;
3003		break;
3004	default:
3005		break;
3006	}
3007
3008	mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), -nr_pages);
 
 
 
3009
3010	ClearPageCgroupUsed(pc);
3011	/*
3012	 * pc->mem_cgroup is not cleared here. It will be accessed when it's
3013	 * freed from LRU. This is safe because uncharged page is expected not
3014	 * to be reused (freed soon). Exception is SwapCache, it's handled by
3015	 * special functions.
3016	 */
3017
3018	unlock_page_cgroup(pc);
3019	/*
3020	 * even after unlock, we have mem->res.usage here and this memcg
3021	 * will never be freed.
 
 
 
 
 
 
 
 
3022	 */
3023	memcg_check_events(mem, page);
3024	if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
3025		mem_cgroup_swap_statistics(mem, true);
3026		mem_cgroup_get(mem);
3027	}
3028	if (!mem_cgroup_is_root(mem))
3029		mem_cgroup_do_uncharge(mem, nr_pages, ctype);
3030
3031	return mem;
3032
3033unlock_out:
3034	unlock_page_cgroup(pc);
3035	return NULL;
3036}
3037
3038void mem_cgroup_uncharge_page(struct page *page)
3039{
3040	/* early check. */
3041	if (page_mapped(page))
3042		return;
3043	if (page->mapping && !PageAnon(page))
3044		return;
3045	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
3046}
3047
3048void mem_cgroup_uncharge_cache_page(struct page *page)
 
3049{
3050	VM_BUG_ON(page_mapped(page));
3051	VM_BUG_ON(page->mapping);
3052	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
3053}
3054
3055/*
3056 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
3057 * In that cases, pages are freed continuously and we can expect pages
3058 * are in the same memcg. All these calls itself limits the number of
3059 * pages freed at once, then uncharge_start/end() is called properly.
3060 * This may be called prural(2) times in a context,
3061 */
3062
3063void mem_cgroup_uncharge_start(void)
3064{
3065	current->memcg_batch.do_batch++;
3066	/* We can do nest. */
3067	if (current->memcg_batch.do_batch == 1) {
3068		current->memcg_batch.memcg = NULL;
3069		current->memcg_batch.nr_pages = 0;
3070		current->memcg_batch.memsw_nr_pages = 0;
3071	}
 
 
 
 
3072}
3073
3074void mem_cgroup_uncharge_end(void)
3075{
3076	struct memcg_batch_info *batch = &current->memcg_batch;
 
3077
3078	if (!batch->do_batch)
3079		return;
 
 
 
 
3080
3081	batch->do_batch--;
3082	if (batch->do_batch) /* If stacked, do nothing. */
3083		return;
 
3084
3085	if (!batch->memcg)
3086		return;
3087	/*
3088	 * This "batch->memcg" is valid without any css_get/put etc...
3089	 * bacause we hide charges behind us.
3090	 */
3091	if (batch->nr_pages)
3092		res_counter_uncharge(&batch->memcg->res,
3093				     batch->nr_pages * PAGE_SIZE);
3094	if (batch->memsw_nr_pages)
3095		res_counter_uncharge(&batch->memcg->memsw,
3096				     batch->memsw_nr_pages * PAGE_SIZE);
3097	memcg_oom_recover(batch->memcg);
3098	/* forget this pointer (for sanity check) */
3099	batch->memcg = NULL;
3100}
3101
3102#ifdef CONFIG_SWAP
3103/*
3104 * called after __delete_from_swap_cache() and drop "page" account.
3105 * memcg information is recorded to swap_cgroup of "ent"
3106 */
3107void
3108mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
3109{
3110	struct mem_cgroup *memcg;
3111	int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
3112
3113	if (!swapout) /* this was a swap cache but the swap is unused ! */
3114		ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
3115
3116	memcg = __mem_cgroup_uncharge_common(page, ctype);
 
 
3117
3118	/*
3119	 * record memcg information,  if swapout && memcg != NULL,
3120	 * mem_cgroup_get() was called in uncharge().
3121	 */
3122	if (do_swap_account && swapout && memcg)
3123		swap_cgroup_record(ent, css_id(&memcg->css));
3124}
3125#endif
 
 
3126
3127#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
3128/*
3129 * called from swap_entry_free(). remove record in swap_cgroup and
3130 * uncharge "memsw" account.
3131 */
3132void mem_cgroup_uncharge_swap(swp_entry_t ent)
3133{
3134	struct mem_cgroup *memcg;
3135	unsigned short id;
3136
3137	if (!do_swap_account)
3138		return;
3139
3140	id = swap_cgroup_record(ent, 0);
3141	rcu_read_lock();
3142	memcg = mem_cgroup_lookup(id);
3143	if (memcg) {
3144		/*
3145		 * We uncharge this because swap is freed.
3146		 * This memcg can be obsolete one. We avoid calling css_tryget
3147		 */
3148		if (!mem_cgroup_is_root(memcg))
3149			res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
3150		mem_cgroup_swap_statistics(memcg, false);
3151		mem_cgroup_put(memcg);
3152	}
3153	rcu_read_unlock();
3154}
3155
3156/**
3157 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3158 * @entry: swap entry to be moved
3159 * @from:  mem_cgroup which the entry is moved from
3160 * @to:  mem_cgroup which the entry is moved to
3161 * @need_fixup: whether we should fixup res_counters and refcounts.
3162 *
3163 * It succeeds only when the swap_cgroup's record for this entry is the same
3164 * as the mem_cgroup's id of @from.
3165 *
3166 * Returns 0 on success, -EINVAL on failure.
3167 *
3168 * The caller must have charged to @to, IOW, called res_counter_charge() about
3169 * both res and memsw, and called css_get().
3170 */
3171static int mem_cgroup_move_swap_account(swp_entry_t entry,
3172		struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
3173{
3174	unsigned short old_id, new_id;
3175
3176	old_id = css_id(&from->css);
3177	new_id = css_id(&to->css);
3178
3179	if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
3180		mem_cgroup_swap_statistics(from, false);
3181		mem_cgroup_swap_statistics(to, true);
3182		/*
3183		 * This function is only called from task migration context now.
3184		 * It postpones res_counter and refcount handling till the end
3185		 * of task migration(mem_cgroup_clear_mc()) for performance
3186		 * improvement. But we cannot postpone mem_cgroup_get(to)
3187		 * because if the process that has been moved to @to does
3188		 * swap-in, the refcount of @to might be decreased to 0.
3189		 */
3190		mem_cgroup_get(to);
3191		if (need_fixup) {
3192			if (!mem_cgroup_is_root(from))
3193				res_counter_uncharge(&from->memsw, PAGE_SIZE);
3194			mem_cgroup_put(from);
3195			/*
3196			 * we charged both to->res and to->memsw, so we should
3197			 * uncharge to->res.
3198			 */
3199			if (!mem_cgroup_is_root(to))
3200				res_counter_uncharge(&to->res, PAGE_SIZE);
3201		}
3202		return 0;
3203	}
3204	return -EINVAL;
3205}
3206#else
3207static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
3208		struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup)
3209{
3210	return -EINVAL;
3211}
3212#endif
3213
3214/*
3215 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
3216 * page belongs to.
3217 */
3218int mem_cgroup_prepare_migration(struct page *page,
3219	struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask)
3220{
3221	struct mem_cgroup *mem = NULL;
3222	struct page_cgroup *pc;
3223	enum charge_type ctype;
3224	int ret = 0;
3225
3226	*ptr = NULL;
3227
3228	VM_BUG_ON(PageTransHuge(page));
3229	if (mem_cgroup_disabled())
3230		return 0;
3231
3232	pc = lookup_page_cgroup(page);
3233	lock_page_cgroup(pc);
3234	if (PageCgroupUsed(pc)) {
3235		mem = pc->mem_cgroup;
3236		css_get(&mem->css);
3237		/*
3238		 * At migrating an anonymous page, its mapcount goes down
3239		 * to 0 and uncharge() will be called. But, even if it's fully
3240		 * unmapped, migration may fail and this page has to be
3241		 * charged again. We set MIGRATION flag here and delay uncharge
3242		 * until end_migration() is called
3243		 *
3244		 * Corner Case Thinking
3245		 * A)
3246		 * When the old page was mapped as Anon and it's unmap-and-freed
3247		 * while migration was ongoing.
3248		 * If unmap finds the old page, uncharge() of it will be delayed
3249		 * until end_migration(). If unmap finds a new page, it's
3250		 * uncharged when it make mapcount to be 1->0. If unmap code
3251		 * finds swap_migration_entry, the new page will not be mapped
3252		 * and end_migration() will find it(mapcount==0).
3253		 *
3254		 * B)
3255		 * When the old page was mapped but migraion fails, the kernel
3256		 * remaps it. A charge for it is kept by MIGRATION flag even
3257		 * if mapcount goes down to 0. We can do remap successfully
3258		 * without charging it again.
3259		 *
3260		 * C)
3261		 * The "old" page is under lock_page() until the end of
3262		 * migration, so, the old page itself will not be swapped-out.
3263		 * If the new page is swapped out before end_migraton, our
3264		 * hook to usual swap-out path will catch the event.
3265		 */
3266		if (PageAnon(page))
3267			SetPageCgroupMigration(pc);
3268	}
3269	unlock_page_cgroup(pc);
3270	/*
3271	 * If the page is not charged at this point,
3272	 * we return here.
3273	 */
3274	if (!mem)
3275		return 0;
3276
3277	*ptr = mem;
3278	ret = __mem_cgroup_try_charge(NULL, gfp_mask, 1, ptr, false);
3279	css_put(&mem->css);/* drop extra refcnt */
3280	if (ret || *ptr == NULL) {
3281		if (PageAnon(page)) {
3282			lock_page_cgroup(pc);
3283			ClearPageCgroupMigration(pc);
3284			unlock_page_cgroup(pc);
3285			/*
3286			 * The old page may be fully unmapped while we kept it.
3287			 */
3288			mem_cgroup_uncharge_page(page);
3289		}
3290		return -ENOMEM;
3291	}
3292	/*
3293	 * We charge new page before it's used/mapped. So, even if unlock_page()
3294	 * is called before end_migration, we can catch all events on this new
3295	 * page. In the case new page is migrated but not remapped, new page's
3296	 * mapcount will be finally 0 and we call uncharge in end_migration().
3297	 */
3298	pc = lookup_page_cgroup(newpage);
3299	if (PageAnon(page))
3300		ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
3301	else if (page_is_file_cache(page))
3302		ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
3303	else
3304		ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
3305	__mem_cgroup_commit_charge(mem, page, 1, pc, ctype);
3306	return ret;
3307}
3308
3309/* remove redundant charge if migration failed*/
3310void mem_cgroup_end_migration(struct mem_cgroup *mem,
3311	struct page *oldpage, struct page *newpage, bool migration_ok)
3312{
3313	struct page *used, *unused;
3314	struct page_cgroup *pc;
3315
3316	if (!mem)
3317		return;
3318	/* blocks rmdir() */
3319	cgroup_exclude_rmdir(&mem->css);
3320	if (!migration_ok) {
3321		used = oldpage;
3322		unused = newpage;
3323	} else {
3324		used = newpage;
3325		unused = oldpage;
3326	}
3327	/*
3328	 * We disallowed uncharge of pages under migration because mapcount
3329	 * of the page goes down to zero, temporarly.
3330	 * Clear the flag and check the page should be charged.
3331	 */
3332	pc = lookup_page_cgroup(oldpage);
3333	lock_page_cgroup(pc);
3334	ClearPageCgroupMigration(pc);
3335	unlock_page_cgroup(pc);
3336
3337	__mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);
3338
3339	/*
3340	 * If a page is a file cache, radix-tree replacement is very atomic
3341	 * and we can skip this check. When it was an Anon page, its mapcount
3342	 * goes down to 0. But because we added MIGRATION flage, it's not
3343	 * uncharged yet. There are several case but page->mapcount check
3344	 * and USED bit check in mem_cgroup_uncharge_page() will do enough
3345	 * check. (see prepare_charge() also)
3346	 */
3347	if (PageAnon(used))
3348		mem_cgroup_uncharge_page(used);
3349	/*
3350	 * At migration, we may charge account against cgroup which has no
3351	 * tasks.
3352	 * So, rmdir()->pre_destroy() can be called while we do this charge.
3353	 * In that case, we need to call pre_destroy() again. check it here.
3354	 */
3355	cgroup_release_and_wakeup_rmdir(&mem->css);
3356}
3357
3358#ifdef CONFIG_DEBUG_VM
3359static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
3360{
3361	struct page_cgroup *pc;
3362
3363	pc = lookup_page_cgroup(page);
3364	if (likely(pc) && PageCgroupUsed(pc))
3365		return pc;
3366	return NULL;
3367}
3368
3369bool mem_cgroup_bad_page_check(struct page *page)
3370{
3371	if (mem_cgroup_disabled())
3372		return false;
3373
3374	return lookup_page_cgroup_used(page) != NULL;
3375}
3376
3377void mem_cgroup_print_bad_page(struct page *page)
3378{
3379	struct page_cgroup *pc;
3380
3381	pc = lookup_page_cgroup_used(page);
3382	if (pc) {
3383		int ret = -1;
3384		char *path;
3385
3386		printk(KERN_ALERT "pc:%p pc->flags:%lx pc->mem_cgroup:%p",
3387		       pc, pc->flags, pc->mem_cgroup);
3388
3389		path = kmalloc(PATH_MAX, GFP_KERNEL);
3390		if (path) {
3391			rcu_read_lock();
3392			ret = cgroup_path(pc->mem_cgroup->css.cgroup,
3393							path, PATH_MAX);
3394			rcu_read_unlock();
3395		}
3396
3397		printk(KERN_CONT "(%s)\n",
3398				(ret < 0) ? "cannot get the path" : path);
3399		kfree(path);
3400	}
3401}
3402#endif
3403
3404static DEFINE_MUTEX(set_limit_mutex);
3405
3406static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
3407				unsigned long long val)
3408{
 
 
 
3409	int retry_count;
3410	u64 memswlimit, memlimit;
3411	int ret = 0;
3412	int children = mem_cgroup_count_children(memcg);
3413	u64 curusage, oldusage;
3414	int enlarge;
3415
3416	/*
3417	 * For keeping hierarchical_reclaim simple, how long we should retry
3418	 * is depends on callers. We set our retry-count to be function
3419	 * of # of children which we should visit in this loop.
3420	 */
3421	retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
 
3422
3423	oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3424
3425	enlarge = 0;
3426	while (retry_count) {
3427		if (signal_pending(current)) {
3428			ret = -EINTR;
3429			break;
3430		}
3431		/*
3432		 * Rather than hide all in some function, I do this in
3433		 * open coded manner. You see what this really does.
3434		 * We have to guarantee mem->res.limit < mem->memsw.limit.
3435		 */
3436		mutex_lock(&set_limit_mutex);
3437		memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3438		if (memswlimit < val) {
3439			ret = -EINVAL;
3440			mutex_unlock(&set_limit_mutex);
3441			break;
3442		}
3443
3444		memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3445		if (memlimit < val)
3446			enlarge = 1;
3447
3448		ret = res_counter_set_limit(&memcg->res, val);
3449		if (!ret) {
3450			if (memswlimit == val)
3451				memcg->memsw_is_minimum = true;
3452			else
3453				memcg->memsw_is_minimum = false;
3454		}
3455		mutex_unlock(&set_limit_mutex);
3456
3457		if (!ret)
3458			break;
3459
3460		mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3461						MEM_CGROUP_RECLAIM_SHRINK,
3462						NULL);
3463		curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3464		/* Usage is reduced ? */
3465  		if (curusage >= oldusage)
3466			retry_count--;
3467		else
3468			oldusage = curusage;
3469	}
 
3470	if (!ret && enlarge)
3471		memcg_oom_recover(memcg);
3472
3473	return ret;
3474}
3475
3476static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
3477					unsigned long long val)
3478{
 
 
 
3479	int retry_count;
3480	u64 memlimit, memswlimit, oldusage, curusage;
3481	int children = mem_cgroup_count_children(memcg);
3482	int ret = -EBUSY;
3483	int enlarge = 0;
3484
3485	/* see mem_cgroup_resize_res_limit */
3486 	retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
3487	oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3488	while (retry_count) {
 
 
 
3489		if (signal_pending(current)) {
3490			ret = -EINTR;
3491			break;
3492		}
3493		/*
3494		 * Rather than hide all in some function, I do this in
3495		 * open coded manner. You see what this really does.
3496		 * We have to guarantee mem->res.limit < mem->memsw.limit.
3497		 */
3498		mutex_lock(&set_limit_mutex);
3499		memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3500		if (memlimit > val) {
3501			ret = -EINVAL;
3502			mutex_unlock(&set_limit_mutex);
3503			break;
3504		}
3505		memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3506		if (memswlimit < val)
3507			enlarge = 1;
3508		ret = res_counter_set_limit(&memcg->memsw, val);
3509		if (!ret) {
3510			if (memlimit == val)
3511				memcg->memsw_is_minimum = true;
3512			else
3513				memcg->memsw_is_minimum = false;
3514		}
3515		mutex_unlock(&set_limit_mutex);
3516
3517		if (!ret)
3518			break;
3519
3520		mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
3521						MEM_CGROUP_RECLAIM_NOSWAP |
3522						MEM_CGROUP_RECLAIM_SHRINK,
3523						NULL);
3524		curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3525		/* Usage is reduced ? */
3526		if (curusage >= oldusage)
3527			retry_count--;
3528		else
3529			oldusage = curusage;
3530	}
 
3531	if (!ret && enlarge)
3532		memcg_oom_recover(memcg);
 
3533	return ret;
3534}
3535
3536unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3537					    gfp_t gfp_mask,
3538					    unsigned long *total_scanned)
3539{
3540	unsigned long nr_reclaimed = 0;
3541	struct mem_cgroup_per_zone *mz, *next_mz = NULL;
3542	unsigned long reclaimed;
3543	int loop = 0;
3544	struct mem_cgroup_tree_per_zone *mctz;
3545	unsigned long long excess;
3546	unsigned long nr_scanned;
3547
3548	if (order > 0)
3549		return 0;
3550
3551	mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3552	/*
3553	 * This loop can run a while, specially if mem_cgroup's continuously
3554	 * keep exceeding their soft limit and putting the system under
3555	 * pressure
3556	 */
3557	do {
3558		if (next_mz)
3559			mz = next_mz;
3560		else
3561			mz = mem_cgroup_largest_soft_limit_node(mctz);
3562		if (!mz)
3563			break;
3564
3565		nr_scanned = 0;
3566		reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone,
3567						gfp_mask,
3568						MEM_CGROUP_RECLAIM_SOFT,
3569						&nr_scanned);
3570		nr_reclaimed += reclaimed;
3571		*total_scanned += nr_scanned;
3572		spin_lock(&mctz->lock);
 
3573
3574		/*
3575		 * If we failed to reclaim anything from this memory cgroup
3576		 * it is time to move on to the next cgroup
3577		 */
3578		next_mz = NULL;
3579		if (!reclaimed) {
3580			do {
3581				/*
3582				 * Loop until we find yet another one.
3583				 *
3584				 * By the time we get the soft_limit lock
3585				 * again, someone might have aded the
3586				 * group back on the RB tree. Iterate to
3587				 * make sure we get a different mem.
3588				 * mem_cgroup_largest_soft_limit_node returns
3589				 * NULL if no other cgroup is present on
3590				 * the tree
3591				 */
3592				next_mz =
3593				__mem_cgroup_largest_soft_limit_node(mctz);
3594				if (next_mz == mz)
3595					css_put(&next_mz->mem->css);
3596				else /* next_mz == NULL or other memcg */
3597					break;
3598			} while (1);
3599		}
3600		__mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
3601		excess = res_counter_soft_limit_excess(&mz->mem->res);
3602		/*
3603		 * One school of thought says that we should not add
3604		 * back the node to the tree if reclaim returns 0.
3605		 * But our reclaim could return 0, simply because due
3606		 * to priority we are exposing a smaller subset of
3607		 * memory to reclaim from. Consider this as a longer
3608		 * term TODO.
3609		 */
3610		/* If excess == 0, no tree ops */
3611		__mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess);
3612		spin_unlock(&mctz->lock);
3613		css_put(&mz->mem->css);
3614		loop++;
3615		/*
3616		 * Could not reclaim anything and there are no more
3617		 * mem cgroups to try or we seem to be looping without
3618		 * reclaiming anything.
3619		 */
3620		if (!nr_reclaimed &&
3621			(next_mz == NULL ||
3622			loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
3623			break;
3624	} while (!nr_reclaimed);
3625	if (next_mz)
3626		css_put(&next_mz->mem->css);
3627	return nr_reclaimed;
3628}
3629
3630/*
3631 * This routine traverse page_cgroup in given list and drop them all.
3632 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
 
 
3633 */
3634static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
3635				int node, int zid, enum lru_list lru)
3636{
3637	struct zone *zone;
3638	struct mem_cgroup_per_zone *mz;
3639	struct page_cgroup *pc, *busy;
3640	unsigned long flags, loop;
3641	struct list_head *list;
3642	int ret = 0;
3643
3644	zone = &NODE_DATA(node)->node_zones[zid];
3645	mz = mem_cgroup_zoneinfo(mem, node, zid);
3646	list = &mz->lists[lru];
3647
3648	loop = MEM_CGROUP_ZSTAT(mz, lru);
3649	/* give some margin against EBUSY etc...*/
3650	loop += 256;
3651	busy = NULL;
3652	while (loop--) {
3653		struct page *page;
3654
3655		ret = 0;
3656		spin_lock_irqsave(&zone->lru_lock, flags);
3657		if (list_empty(list)) {
3658			spin_unlock_irqrestore(&zone->lru_lock, flags);
3659			break;
3660		}
3661		pc = list_entry(list->prev, struct page_cgroup, lru);
3662		if (busy == pc) {
3663			list_move(&pc->lru, list);
3664			busy = NULL;
3665			spin_unlock_irqrestore(&zone->lru_lock, flags);
3666			continue;
3667		}
3668		spin_unlock_irqrestore(&zone->lru_lock, flags);
3669
3670		page = lookup_cgroup_page(pc);
3671
3672		ret = mem_cgroup_move_parent(page, pc, mem, GFP_KERNEL);
3673		if (ret == -ENOMEM)
3674			break;
3675
3676		if (ret == -EBUSY || ret == -EINVAL) {
3677			/* found lock contention or "pc" is obsolete. */
3678			busy = pc;
3679			cond_resched();
3680		} else
3681			busy = NULL;
3682	}
3683
3684	if (!ret && !list_empty(list))
3685		return -EBUSY;
 
3686	return ret;
3687}
3688
3689/*
3690 * make mem_cgroup's charge to be 0 if there is no task.
3691 * This enables deleting this mem_cgroup.
 
 
3692 */
3693static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
3694{
3695	int ret;
3696	int node, zid, shrink;
3697	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3698	struct cgroup *cgrp = mem->css.cgroup;
3699
3700	css_get(&mem->css);
3701
3702	shrink = 0;
3703	/* should free all ? */
3704	if (free_all)
3705		goto try_to_free;
3706move_account:
3707	do {
3708		ret = -EBUSY;
3709		if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
3710			goto out;
3711		ret = -EINTR;
3712		if (signal_pending(current))
3713			goto out;
3714		/* This is for making all *used* pages to be on LRU. */
3715		lru_add_drain_all();
3716		drain_all_stock_sync(mem);
3717		ret = 0;
3718		mem_cgroup_start_move(mem);
3719		for_each_node_state(node, N_HIGH_MEMORY) {
3720			for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
3721				enum lru_list l;
3722				for_each_lru(l) {
3723					ret = mem_cgroup_force_empty_list(mem,
3724							node, zid, l);
3725					if (ret)
3726						break;
3727				}
3728			}
3729			if (ret)
3730				break;
3731		}
3732		mem_cgroup_end_move(mem);
3733		memcg_oom_recover(mem);
3734		/* it seems parent cgroup doesn't have enough mem */
3735		if (ret == -ENOMEM)
3736			goto try_to_free;
3737		cond_resched();
3738	/* "ret" should also be checked to ensure all lists are empty. */
3739	} while (mem->res.usage > 0 || ret);
3740out:
3741	css_put(&mem->css);
3742	return ret;
3743
3744try_to_free:
3745	/* returns EBUSY if there is a task or if we come here twice. */
3746	if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
3747		ret = -EBUSY;
3748		goto out;
3749	}
3750	/* we call try-to-free pages for make this cgroup empty */
3751	lru_add_drain_all();
3752	/* try to free all pages in this cgroup */
3753	shrink = 1;
3754	while (nr_retries && mem->res.usage > 0) {
3755		int progress;
3756
3757		if (signal_pending(current)) {
3758			ret = -EINTR;
3759			goto out;
3760		}
3761		progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
3762						false);
3763		if (!progress) {
3764			nr_retries--;
3765			/* maybe some writeback is necessary */
3766			congestion_wait(BLK_RW_ASYNC, HZ/10);
3767		}
3768
3769	}
3770	lru_add_drain();
3771	/* try move_account...there may be some *locked* pages. */
3772	goto move_account;
3773}
3774
3775int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
 
 
3776{
3777	return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
3778}
3779
 
 
 
 
3780
3781static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
 
3782{
3783	return mem_cgroup_from_cont(cont)->use_hierarchy;
3784}
3785
3786static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
3787					u64 val)
3788{
3789	int retval = 0;
3790	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3791	struct cgroup *parent = cont->parent;
3792	struct mem_cgroup *parent_mem = NULL;
3793
3794	if (parent)
3795		parent_mem = mem_cgroup_from_cont(parent);
3796
3797	cgroup_lock();
3798	/*
3799	 * If parent's use_hierarchy is set, we can't make any modifications
3800	 * in the child subtrees. If it is unset, then the change can
3801	 * occur, provided the current cgroup has no children.
3802	 *
3803	 * For the root cgroup, parent_mem is NULL, we allow value to be
3804	 * set if there are no children.
3805	 */
3806	if ((!parent_mem || !parent_mem->use_hierarchy) &&
3807				(val == 1 || val == 0)) {
3808		if (list_empty(&cont->children))
3809			mem->use_hierarchy = val;
3810		else
3811			retval = -EBUSY;
3812	} else
3813		retval = -EINVAL;
3814	cgroup_unlock();
3815
3816	return retval;
3817}
3818
3819
3820static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *mem,
3821					       enum mem_cgroup_stat_index idx)
3822{
3823	struct mem_cgroup *iter;
3824	long val = 0;
3825
3826	/* Per-cpu values can be negative, use a signed accumulator */
3827	for_each_mem_cgroup_tree(iter, mem)
3828		val += mem_cgroup_read_stat(iter, idx);
3829
3830	if (val < 0) /* race ? */
3831		val = 0;
3832	return val;
 
3833}
3834
3835static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap)
3836{
3837	u64 val;
 
3838
3839	if (!mem_cgroup_is_root(mem)) {
3840		if (!swap)
3841			return res_counter_read_u64(&mem->res, RES_USAGE);
3842		else
3843			return res_counter_read_u64(&mem->memsw, RES_USAGE);
3844	}
 
3845
3846	val = mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_CACHE);
3847	val += mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_RSS);
 
3848
3849	if (swap)
3850		val += mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
3851
3852	return val << PAGE_SHIFT;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3853}
3854
3855static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
 
 
 
 
 
 
 
 
 
3856{
3857	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
3858	u64 val;
3859	int type, name;
3860
3861	type = MEMFILE_TYPE(cft->private);
3862	name = MEMFILE_ATTR(cft->private);
3863	switch (type) {
3864	case _MEM:
3865		if (name == RES_USAGE)
3866			val = mem_cgroup_usage(mem, false);
3867		else
3868			val = res_counter_read_u64(&mem->res, name);
3869		break;
3870	case _MEMSWAP:
3871		if (name == RES_USAGE)
3872			val = mem_cgroup_usage(mem, true);
3873		else
3874			val = res_counter_read_u64(&mem->memsw, name);
 
 
 
3875		break;
3876	default:
3877		BUG();
3878		break;
3879	}
3880	return val;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3881}
 
3882/*
3883 * The user of this function is...
3884 * RES_LIMIT.
3885 */
3886static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
3887			    const char *buffer)
3888{
3889	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3890	int type, name;
3891	unsigned long long val;
3892	int ret;
3893
3894	type = MEMFILE_TYPE(cft->private);
3895	name = MEMFILE_ATTR(cft->private);
3896	switch (name) {
 
 
 
3897	case RES_LIMIT:
3898		if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
3899			ret = -EINVAL;
3900			break;
3901		}
3902		/* This function does all necessary parse...reuse it */
3903		ret = res_counter_memparse_write_strategy(buffer, &val);
3904		if (ret)
3905			break;
3906		if (type == _MEM)
3907			ret = mem_cgroup_resize_limit(memcg, val);
3908		else
3909			ret = mem_cgroup_resize_memsw_limit(memcg, val);
3910		break;
3911	case RES_SOFT_LIMIT:
3912		ret = res_counter_memparse_write_strategy(buffer, &val);
3913		if (ret)
3914			break;
3915		/*
3916		 * For memsw, soft limits are hard to implement in terms
3917		 * of semantics, for now, we support soft limits for
3918		 * control without swap
3919		 */
3920		if (type == _MEM)
3921			ret = res_counter_set_soft_limit(&memcg->res, val);
3922		else
3923			ret = -EINVAL;
3924		break;
3925	default:
3926		ret = -EINVAL; /* should be BUG() ? */
 
3927		break;
3928	}
3929	return ret;
3930}
3931
3932static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
3933		unsigned long long *mem_limit, unsigned long long *memsw_limit)
3934{
3935	struct cgroup *cgroup;
3936	unsigned long long min_limit, min_memsw_limit, tmp;
3937
3938	min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3939	min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3940	cgroup = memcg->css.cgroup;
3941	if (!memcg->use_hierarchy)
3942		goto out;
3943
3944	while (cgroup->parent) {
3945		cgroup = cgroup->parent;
3946		memcg = mem_cgroup_from_cont(cgroup);
3947		if (!memcg->use_hierarchy)
3948			break;
3949		tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
3950		min_limit = min(min_limit, tmp);
3951		tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3952		min_memsw_limit = min(min_memsw_limit, tmp);
3953	}
3954out:
3955	*mem_limit = min_limit;
3956	*memsw_limit = min_memsw_limit;
3957	return;
3958}
3959
3960static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
3961{
3962	struct mem_cgroup *mem;
3963	int type, name;
3964
3965	mem = mem_cgroup_from_cont(cont);
3966	type = MEMFILE_TYPE(event);
3967	name = MEMFILE_ATTR(event);
3968	switch (name) {
3969	case RES_MAX_USAGE:
3970		if (type == _MEM)
3971			res_counter_reset_max(&mem->res);
3972		else
3973			res_counter_reset_max(&mem->memsw);
3974		break;
3975	case RES_FAILCNT:
3976		if (type == _MEM)
3977			res_counter_reset_failcnt(&mem->res);
3978		else
3979			res_counter_reset_failcnt(&mem->memsw);
3980		break;
 
 
3981	}
3982
3983	return 0;
3984}
3985
3986static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
3987					struct cftype *cft)
3988{
3989	return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
3990}
3991
3992#ifdef CONFIG_MMU
3993static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
3994					struct cftype *cft, u64 val)
3995{
3996	struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
3997
3998	if (val >= (1 << NR_MOVE_TYPE))
3999		return -EINVAL;
4000	/*
4001	 * We check this value several times in both in can_attach() and
4002	 * attach(), so we need cgroup lock to prevent this value from being
4003	 * inconsistent.
4004	 */
4005	cgroup_lock();
4006	mem->move_charge_at_immigrate = val;
4007	cgroup_unlock();
4008
 
 
 
 
 
 
 
4009	return 0;
4010}
4011#else
4012static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
4013					struct cftype *cft, u64 val)
4014{
4015	return -ENOSYS;
4016}
4017#endif
4018
4019
4020/* For read statistics */
4021enum {
4022	MCS_CACHE,
4023	MCS_RSS,
4024	MCS_FILE_MAPPED,
4025	MCS_PGPGIN,
4026	MCS_PGPGOUT,
4027	MCS_SWAP,
4028	MCS_PGFAULT,
4029	MCS_PGMAJFAULT,
4030	MCS_INACTIVE_ANON,
4031	MCS_ACTIVE_ANON,
4032	MCS_INACTIVE_FILE,
4033	MCS_ACTIVE_FILE,
4034	MCS_UNEVICTABLE,
4035	NR_MCS_STAT,
4036};
4037
4038struct mcs_total_stat {
4039	s64 stat[NR_MCS_STAT];
4040};
4041
4042struct {
4043	char *local_name;
4044	char *total_name;
4045} memcg_stat_strings[NR_MCS_STAT] = {
4046	{"cache", "total_cache"},
4047	{"rss", "total_rss"},
4048	{"mapped_file", "total_mapped_file"},
4049	{"pgpgin", "total_pgpgin"},
4050	{"pgpgout", "total_pgpgout"},
4051	{"swap", "total_swap"},
4052	{"pgfault", "total_pgfault"},
4053	{"pgmajfault", "total_pgmajfault"},
4054	{"inactive_anon", "total_inactive_anon"},
4055	{"active_anon", "total_active_anon"},
4056	{"inactive_file", "total_inactive_file"},
4057	{"active_file", "total_active_file"},
4058	{"unevictable", "total_unevictable"}
4059};
4060
4061
4062static void
4063mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
4064{
4065	s64 val;
4066
4067	/* per cpu stat */
4068	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
4069	s->stat[MCS_CACHE] += val * PAGE_SIZE;
4070	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
4071	s->stat[MCS_RSS] += val * PAGE_SIZE;
4072	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED);
4073	s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
4074	val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGPGIN);
4075	s->stat[MCS_PGPGIN] += val;
4076	val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGPGOUT);
4077	s->stat[MCS_PGPGOUT] += val;
4078	if (do_swap_account) {
4079		val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
4080		s->stat[MCS_SWAP] += val * PAGE_SIZE;
4081	}
4082	val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGFAULT);
4083	s->stat[MCS_PGFAULT] += val;
4084	val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGMAJFAULT);
4085	s->stat[MCS_PGMAJFAULT] += val;
4086
4087	/* per zone stat */
4088	val = mem_cgroup_nr_lru_pages(mem, BIT(LRU_INACTIVE_ANON));
4089	s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
4090	val = mem_cgroup_nr_lru_pages(mem, BIT(LRU_ACTIVE_ANON));
4091	s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE;
4092	val = mem_cgroup_nr_lru_pages(mem, BIT(LRU_INACTIVE_FILE));
4093	s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE;
4094	val = mem_cgroup_nr_lru_pages(mem, BIT(LRU_ACTIVE_FILE));
4095	s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE;
4096	val = mem_cgroup_nr_lru_pages(mem, BIT(LRU_UNEVICTABLE));
4097	s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE;
4098}
4099
4100static void
4101mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
4102{
4103	struct mem_cgroup *iter;
4104
4105	for_each_mem_cgroup_tree(iter, mem)
4106		mem_cgroup_get_local_stat(iter, s);
4107}
4108
4109#ifdef CONFIG_NUMA
4110static int mem_control_numa_stat_show(struct seq_file *m, void *arg)
4111{
 
 
 
 
 
 
 
 
 
 
 
 
4112	int nid;
4113	unsigned long total_nr, file_nr, anon_nr, unevictable_nr;
4114	unsigned long node_nr;
4115	struct cgroup *cont = m->private;
4116	struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
4117
4118	total_nr = mem_cgroup_nr_lru_pages(mem_cont, LRU_ALL);
4119	seq_printf(m, "total=%lu", total_nr);
4120	for_each_node_state(nid, N_HIGH_MEMORY) {
4121		node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid, LRU_ALL);
4122		seq_printf(m, " N%d=%lu", nid, node_nr);
4123	}
4124	seq_putc(m, '\n');
4125
4126	file_nr = mem_cgroup_nr_lru_pages(mem_cont, LRU_ALL_FILE);
4127	seq_printf(m, "file=%lu", file_nr);
4128	for_each_node_state(nid, N_HIGH_MEMORY) {
4129		node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid,
4130				LRU_ALL_FILE);
4131		seq_printf(m, " N%d=%lu", nid, node_nr);
4132	}
4133	seq_putc(m, '\n');
4134
4135	anon_nr = mem_cgroup_nr_lru_pages(mem_cont, LRU_ALL_ANON);
4136	seq_printf(m, "anon=%lu", anon_nr);
4137	for_each_node_state(nid, N_HIGH_MEMORY) {
4138		node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid,
4139				LRU_ALL_ANON);
4140		seq_printf(m, " N%d=%lu", nid, node_nr);
4141	}
4142	seq_putc(m, '\n');
4143
4144	unevictable_nr = mem_cgroup_nr_lru_pages(mem_cont, BIT(LRU_UNEVICTABLE));
4145	seq_printf(m, "unevictable=%lu", unevictable_nr);
4146	for_each_node_state(nid, N_HIGH_MEMORY) {
4147		node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid,
4148				BIT(LRU_UNEVICTABLE));
4149		seq_printf(m, " N%d=%lu", nid, node_nr);
4150	}
4151	seq_putc(m, '\n');
4152	return 0;
4153}
4154#endif /* CONFIG_NUMA */
4155
4156static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
4157				 struct cgroup_map_cb *cb)
4158{
4159	struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
4160	struct mcs_total_stat mystat;
4161	int i;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4162
4163	memset(&mystat, 0, sizeof(mystat));
4164	mem_cgroup_get_local_stat(mem_cont, &mystat);
 
4165
 
 
 
4166
4167	for (i = 0; i < NR_MCS_STAT; i++) {
4168		if (i == MCS_SWAP && !do_swap_account)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4169			continue;
4170		cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
 
 
4171	}
4172
4173	/* Hierarchical information */
4174	{
4175		unsigned long long limit, memsw_limit;
4176		memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
4177		cb->fill(cb, "hierarchical_memory_limit", limit);
4178		if (do_swap_account)
4179			cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
4180	}
4181
4182	memset(&mystat, 0, sizeof(mystat));
4183	mem_cgroup_get_total_stat(mem_cont, &mystat);
4184	for (i = 0; i < NR_MCS_STAT; i++) {
4185		if (i == MCS_SWAP && !do_swap_account)
4186			continue;
4187		cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
4188	}
4189
4190#ifdef CONFIG_DEBUG_VM
4191	cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
4192
4193	{
4194		int nid, zid;
4195		struct mem_cgroup_per_zone *mz;
 
4196		unsigned long recent_rotated[2] = {0, 0};
4197		unsigned long recent_scanned[2] = {0, 0};
4198
4199		for_each_online_node(nid)
4200			for (zid = 0; zid < MAX_NR_ZONES; zid++) {
4201				mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
 
4202
4203				recent_rotated[0] +=
4204					mz->reclaim_stat.recent_rotated[0];
4205				recent_rotated[1] +=
4206					mz->reclaim_stat.recent_rotated[1];
4207				recent_scanned[0] +=
4208					mz->reclaim_stat.recent_scanned[0];
4209				recent_scanned[1] +=
4210					mz->reclaim_stat.recent_scanned[1];
4211			}
4212		cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
4213		cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
4214		cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
4215		cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
4216	}
4217#endif
4218
4219	return 0;
4220}
4221
4222static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
 
4223{
4224	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4225
4226	return mem_cgroup_swappiness(memcg);
4227}
4228
4229static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
4230				       u64 val)
4231{
4232	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4233	struct mem_cgroup *parent;
4234
4235	if (val > 100)
4236		return -EINVAL;
4237
4238	if (cgrp->parent == NULL)
4239		return -EINVAL;
4240
4241	parent = mem_cgroup_from_cont(cgrp->parent);
4242
4243	cgroup_lock();
4244
4245	/* If under hierarchy, only empty-root can set this value */
4246	if ((parent->use_hierarchy) ||
4247	    (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
4248		cgroup_unlock();
4249		return -EINVAL;
4250	}
4251
4252	memcg->swappiness = val;
4253
4254	cgroup_unlock();
4255
4256	return 0;
4257}
4258
4259static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
4260{
4261	struct mem_cgroup_threshold_ary *t;
4262	u64 usage;
4263	int i;
4264
4265	rcu_read_lock();
4266	if (!swap)
4267		t = rcu_dereference(memcg->thresholds.primary);
4268	else
4269		t = rcu_dereference(memcg->memsw_thresholds.primary);
4270
4271	if (!t)
4272		goto unlock;
4273
4274	usage = mem_cgroup_usage(memcg, swap);
4275
4276	/*
4277	 * current_threshold points to threshold just below usage.
4278	 * If it's not true, a threshold was crossed after last
4279	 * call of __mem_cgroup_threshold().
4280	 */
4281	i = t->current_threshold;
4282
4283	/*
4284	 * Iterate backward over array of thresholds starting from
4285	 * current_threshold and check if a threshold is crossed.
4286	 * If none of thresholds below usage is crossed, we read
4287	 * only one element of the array here.
4288	 */
4289	for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
4290		eventfd_signal(t->entries[i].eventfd, 1);
4291
4292	/* i = current_threshold + 1 */
4293	i++;
4294
4295	/*
4296	 * Iterate forward over array of thresholds starting from
4297	 * current_threshold+1 and check if a threshold is crossed.
4298	 * If none of thresholds above usage is crossed, we read
4299	 * only one element of the array here.
4300	 */
4301	for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
4302		eventfd_signal(t->entries[i].eventfd, 1);
4303
4304	/* Update current_threshold */
4305	t->current_threshold = i - 1;
4306unlock:
4307	rcu_read_unlock();
4308}
4309
4310static void mem_cgroup_threshold(struct mem_cgroup *memcg)
4311{
4312	while (memcg) {
4313		__mem_cgroup_threshold(memcg, false);
4314		if (do_swap_account)
4315			__mem_cgroup_threshold(memcg, true);
4316
4317		memcg = parent_mem_cgroup(memcg);
4318	}
4319}
4320
4321static int compare_thresholds(const void *a, const void *b)
4322{
4323	const struct mem_cgroup_threshold *_a = a;
4324	const struct mem_cgroup_threshold *_b = b;
4325
4326	return _a->threshold - _b->threshold;
 
 
 
 
 
 
4327}
4328
4329static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem)
4330{
4331	struct mem_cgroup_eventfd_list *ev;
4332
4333	list_for_each_entry(ev, &mem->oom_notify, list)
 
 
4334		eventfd_signal(ev->eventfd, 1);
 
 
4335	return 0;
4336}
4337
4338static void mem_cgroup_oom_notify(struct mem_cgroup *mem)
4339{
4340	struct mem_cgroup *iter;
4341
4342	for_each_mem_cgroup_tree(iter, mem)
4343		mem_cgroup_oom_notify_cb(iter);
4344}
4345
4346static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
4347	struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
4348{
4349	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4350	struct mem_cgroup_thresholds *thresholds;
4351	struct mem_cgroup_threshold_ary *new;
4352	int type = MEMFILE_TYPE(cft->private);
4353	u64 threshold, usage;
4354	int i, size, ret;
4355
4356	ret = res_counter_memparse_write_strategy(args, &threshold);
4357	if (ret)
4358		return ret;
4359
4360	mutex_lock(&memcg->thresholds_lock);
4361
4362	if (type == _MEM)
4363		thresholds = &memcg->thresholds;
4364	else if (type == _MEMSWAP)
 
4365		thresholds = &memcg->memsw_thresholds;
4366	else
 
4367		BUG();
4368
4369	usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
4370
4371	/* Check if a threshold crossed before adding a new one */
4372	if (thresholds->primary)
4373		__mem_cgroup_threshold(memcg, type == _MEMSWAP);
4374
4375	size = thresholds->primary ? thresholds->primary->size + 1 : 1;
4376
4377	/* Allocate memory for new array of thresholds */
4378	new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
4379			GFP_KERNEL);
4380	if (!new) {
4381		ret = -ENOMEM;
4382		goto unlock;
4383	}
4384	new->size = size;
4385
4386	/* Copy thresholds (if any) to new array */
4387	if (thresholds->primary) {
4388		memcpy(new->entries, thresholds->primary->entries, (size - 1) *
4389				sizeof(struct mem_cgroup_threshold));
4390	}
4391
4392	/* Add new threshold */
4393	new->entries[size - 1].eventfd = eventfd;
4394	new->entries[size - 1].threshold = threshold;
4395
4396	/* Sort thresholds. Registering of new threshold isn't time-critical */
4397	sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
4398			compare_thresholds, NULL);
4399
4400	/* Find current threshold */
4401	new->current_threshold = -1;
4402	for (i = 0; i < size; i++) {
4403		if (new->entries[i].threshold < usage) {
4404			/*
4405			 * new->current_threshold will not be used until
4406			 * rcu_assign_pointer(), so it's safe to increment
4407			 * it here.
4408			 */
4409			++new->current_threshold;
4410		}
 
4411	}
4412
4413	/* Free old spare buffer and save old primary buffer as spare */
4414	kfree(thresholds->spare);
4415	thresholds->spare = thresholds->primary;
4416
4417	rcu_assign_pointer(thresholds->primary, new);
4418
4419	/* To be sure that nobody uses thresholds */
4420	synchronize_rcu();
4421
4422unlock:
4423	mutex_unlock(&memcg->thresholds_lock);
4424
4425	return ret;
4426}
4427
4428static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
4429	struct cftype *cft, struct eventfd_ctx *eventfd)
 
 
 
 
 
 
 
 
 
 
 
 
4430{
4431	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4432	struct mem_cgroup_thresholds *thresholds;
4433	struct mem_cgroup_threshold_ary *new;
4434	int type = MEMFILE_TYPE(cft->private);
4435	u64 usage;
4436	int i, j, size;
4437
4438	mutex_lock(&memcg->thresholds_lock);
4439	if (type == _MEM)
 
4440		thresholds = &memcg->thresholds;
4441	else if (type == _MEMSWAP)
 
4442		thresholds = &memcg->memsw_thresholds;
4443	else
 
4444		BUG();
4445
4446	/*
4447	 * Something went wrong if we trying to unregister a threshold
4448	 * if we don't have thresholds
4449	 */
4450	BUG_ON(!thresholds);
4451
4452	usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
4453
4454	/* Check if a threshold crossed before removing */
4455	__mem_cgroup_threshold(memcg, type == _MEMSWAP);
4456
4457	/* Calculate new number of threshold */
4458	size = 0;
4459	for (i = 0; i < thresholds->primary->size; i++) {
4460		if (thresholds->primary->entries[i].eventfd != eventfd)
4461			size++;
4462	}
4463
4464	new = thresholds->spare;
4465
4466	/* Set thresholds array to NULL if we don't have thresholds */
4467	if (!size) {
4468		kfree(new);
4469		new = NULL;
4470		goto swap_buffers;
4471	}
4472
4473	new->size = size;
4474
4475	/* Copy thresholds and find current threshold */
4476	new->current_threshold = -1;
4477	for (i = 0, j = 0; i < thresholds->primary->size; i++) {
4478		if (thresholds->primary->entries[i].eventfd == eventfd)
4479			continue;
4480
4481		new->entries[j] = thresholds->primary->entries[i];
4482		if (new->entries[j].threshold < usage) {
4483			/*
4484			 * new->current_threshold will not be used
4485			 * until rcu_assign_pointer(), so it's safe to increment
4486			 * it here.
4487			 */
4488			++new->current_threshold;
4489		}
4490		j++;
4491	}
4492
4493swap_buffers:
4494	/* Swap primary and spare array */
4495	thresholds->spare = thresholds->primary;
 
4496	rcu_assign_pointer(thresholds->primary, new);
4497
4498	/* To be sure that nobody uses thresholds */
4499	synchronize_rcu();
4500
 
 
 
 
 
 
4501	mutex_unlock(&memcg->thresholds_lock);
4502}
4503
4504static int mem_cgroup_oom_register_event(struct cgroup *cgrp,
4505	struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
 
 
 
 
 
 
 
 
 
 
 
 
4506{
4507	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4508	struct mem_cgroup_eventfd_list *event;
4509	int type = MEMFILE_TYPE(cft->private);
4510
4511	BUG_ON(type != _OOM_TYPE);
4512	event = kmalloc(sizeof(*event),	GFP_KERNEL);
4513	if (!event)
4514		return -ENOMEM;
4515
4516	spin_lock(&memcg_oom_lock);
4517
4518	event->eventfd = eventfd;
4519	list_add(&event->list, &memcg->oom_notify);
4520
4521	/* already in OOM ? */
4522	if (atomic_read(&memcg->under_oom))
4523		eventfd_signal(eventfd, 1);
4524	spin_unlock(&memcg_oom_lock);
4525
4526	return 0;
4527}
4528
4529static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
4530	struct cftype *cft, struct eventfd_ctx *eventfd)
4531{
4532	struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4533	struct mem_cgroup_eventfd_list *ev, *tmp;
4534	int type = MEMFILE_TYPE(cft->private);
4535
4536	BUG_ON(type != _OOM_TYPE);
4537
4538	spin_lock(&memcg_oom_lock);
4539
4540	list_for_each_entry_safe(ev, tmp, &mem->oom_notify, list) {
4541		if (ev->eventfd == eventfd) {
4542			list_del(&ev->list);
4543			kfree(ev);
4544		}
4545	}
4546
4547	spin_unlock(&memcg_oom_lock);
4548}
4549
4550static int mem_cgroup_oom_control_read(struct cgroup *cgrp,
4551	struct cftype *cft,  struct cgroup_map_cb *cb)
4552{
4553	struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4554
4555	cb->fill(cb, "oom_kill_disable", mem->oom_kill_disable);
4556
4557	if (atomic_read(&mem->under_oom))
4558		cb->fill(cb, "under_oom", 1);
4559	else
4560		cb->fill(cb, "under_oom", 0);
4561	return 0;
4562}
4563
4564static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
4565	struct cftype *cft, u64 val)
4566{
4567	struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
4568	struct mem_cgroup *parent;
4569
4570	/* cannot set to root cgroup and only 0 and 1 are allowed */
4571	if (!cgrp->parent || !((val == 0) || (val == 1)))
4572		return -EINVAL;
4573
4574	parent = mem_cgroup_from_cont(cgrp->parent);
 
 
 
 
 
4575
4576	cgroup_lock();
4577	/* oom-kill-disable is a flag for subhierarchy. */
4578	if ((parent->use_hierarchy) ||
4579	    (mem->use_hierarchy && !list_empty(&cgrp->children))) {
4580		cgroup_unlock();
4581		return -EINVAL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4582	}
4583	mem->oom_kill_disable = val;
4584	if (!val)
4585		memcg_oom_recover(mem);
4586	cgroup_unlock();
 
 
4587	return 0;
4588}
4589
4590#ifdef CONFIG_NUMA
4591static const struct file_operations mem_control_numa_stat_file_operations = {
4592	.read = seq_read,
4593	.llseek = seq_lseek,
4594	.release = single_release,
4595};
 
 
 
4596
4597static int mem_control_numa_stat_open(struct inode *unused, struct file *file)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4598{
4599	struct cgroup *cont = file->f_dentry->d_parent->d_fsdata;
 
 
4600
4601	file->f_op = &mem_control_numa_stat_file_operations;
4602	return single_open(file, mem_control_numa_stat_show, cont);
 
 
 
 
 
 
 
 
4603}
4604#endif /* CONFIG_NUMA */
4605
4606static struct cftype mem_cgroup_files[] = {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4607	{
4608		.name = "usage_in_bytes",
4609		.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4610		.read_u64 = mem_cgroup_read,
4611		.register_event = mem_cgroup_usage_register_event,
4612		.unregister_event = mem_cgroup_usage_unregister_event,
4613	},
4614	{
4615		.name = "max_usage_in_bytes",
4616		.private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4617		.trigger = mem_cgroup_reset,
4618		.read_u64 = mem_cgroup_read,
4619	},
4620	{
4621		.name = "limit_in_bytes",
4622		.private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4623		.write_string = mem_cgroup_write,
4624		.read_u64 = mem_cgroup_read,
4625	},
4626	{
4627		.name = "soft_limit_in_bytes",
4628		.private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
4629		.write_string = mem_cgroup_write,
4630		.read_u64 = mem_cgroup_read,
4631	},
4632	{
4633		.name = "failcnt",
4634		.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4635		.trigger = mem_cgroup_reset,
4636		.read_u64 = mem_cgroup_read,
4637	},
4638	{
4639		.name = "stat",
4640		.read_map = mem_control_stat_show,
4641	},
4642	{
4643		.name = "force_empty",
4644		.trigger = mem_cgroup_force_empty_write,
4645	},
4646	{
4647		.name = "use_hierarchy",
4648		.write_u64 = mem_cgroup_hierarchy_write,
4649		.read_u64 = mem_cgroup_hierarchy_read,
4650	},
4651	{
 
 
 
 
 
4652		.name = "swappiness",
4653		.read_u64 = mem_cgroup_swappiness_read,
4654		.write_u64 = mem_cgroup_swappiness_write,
4655	},
4656	{
4657		.name = "move_charge_at_immigrate",
4658		.read_u64 = mem_cgroup_move_charge_read,
4659		.write_u64 = mem_cgroup_move_charge_write,
4660	},
4661	{
4662		.name = "oom_control",
4663		.read_map = mem_cgroup_oom_control_read,
4664		.write_u64 = mem_cgroup_oom_control_write,
4665		.register_event = mem_cgroup_oom_register_event,
4666		.unregister_event = mem_cgroup_oom_unregister_event,
4667		.private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
4668	},
 
 
 
4669#ifdef CONFIG_NUMA
4670	{
4671		.name = "numa_stat",
4672		.open = mem_control_numa_stat_open,
4673		.mode = S_IRUGO,
4674	},
4675#endif
4676};
4677
4678#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4679static struct cftype memsw_cgroup_files[] = {
4680	{
4681		.name = "memsw.usage_in_bytes",
4682		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
4683		.read_u64 = mem_cgroup_read,
4684		.register_event = mem_cgroup_usage_register_event,
4685		.unregister_event = mem_cgroup_usage_unregister_event,
4686	},
4687	{
4688		.name = "memsw.max_usage_in_bytes",
4689		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
4690		.trigger = mem_cgroup_reset,
4691		.read_u64 = mem_cgroup_read,
4692	},
4693	{
4694		.name = "memsw.limit_in_bytes",
4695		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
4696		.write_string = mem_cgroup_write,
4697		.read_u64 = mem_cgroup_read,
4698	},
4699	{
4700		.name = "memsw.failcnt",
4701		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
4702		.trigger = mem_cgroup_reset,
4703		.read_u64 = mem_cgroup_read,
 
 
 
 
 
 
 
 
4704	},
4705};
4706
4707static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
4708{
4709	if (!do_swap_account)
4710		return 0;
4711	return cgroup_add_files(cont, ss, memsw_cgroup_files,
4712				ARRAY_SIZE(memsw_cgroup_files));
4713};
4714#else
4715static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
4716{
4717	return 0;
4718}
4719#endif
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4720
4721static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
4722{
4723	struct mem_cgroup_per_node *pn;
4724	struct mem_cgroup_per_zone *mz;
4725	enum lru_list l;
4726	int zone, tmp = node;
4727	/*
4728	 * This routine is called against possible nodes.
4729	 * But it's BUG to call kmalloc() against offline node.
4730	 *
4731	 * TODO: this routine can waste much memory for nodes which will
4732	 *       never be onlined. It's better to use memory hotplug callback
4733	 *       function.
4734	 */
4735	if (!node_state(node, N_NORMAL_MEMORY))
4736		tmp = -1;
4737	pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4738	if (!pn)
4739		return 1;
4740
4741	mem->info.nodeinfo[node] = pn;
4742	for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4743		mz = &pn->zoneinfo[zone];
4744		for_each_lru(l)
4745			INIT_LIST_HEAD(&mz->lists[l]);
4746		mz->usage_in_excess = 0;
4747		mz->on_tree = false;
4748		mz->mem = mem;
4749	}
 
4750	return 0;
4751}
4752
4753static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
4754{
4755	kfree(mem->info.nodeinfo[node]);
4756}
4757
4758static struct mem_cgroup *mem_cgroup_alloc(void)
4759{
4760	struct mem_cgroup *mem;
4761	int size = sizeof(struct mem_cgroup);
4762
4763	/* Can be very big if MAX_NUMNODES is very big */
4764	if (size < PAGE_SIZE)
4765		mem = kzalloc(size, GFP_KERNEL);
4766	else
4767		mem = vzalloc(size);
4768
4769	if (!mem)
4770		return NULL;
4771
4772	mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4773	if (!mem->stat)
4774		goto out_free;
4775	spin_lock_init(&mem->pcp_counter_lock);
4776	return mem;
4777
4778out_free:
4779	if (size < PAGE_SIZE)
4780		kfree(mem);
4781	else
4782		vfree(mem);
4783	return NULL;
4784}
4785
4786/*
4787 * At destroying mem_cgroup, references from swap_cgroup can remain.
4788 * (scanning all at force_empty is too costly...)
4789 *
4790 * Instead of clearing all references at force_empty, we remember
4791 * the number of reference from swap_cgroup and free mem_cgroup when
4792 * it goes down to 0.
4793 *
4794 * Removal of cgroup itself succeeds regardless of refs from swap.
4795 */
4796
4797static void __mem_cgroup_free(struct mem_cgroup *mem)
4798{
 
 
4799	int node;
4800
4801	mem_cgroup_remove_from_trees(mem);
4802	free_css_id(&mem_cgroup_subsys, &mem->css);
4803
4804	for_each_node_state(node, N_POSSIBLE)
4805		free_mem_cgroup_per_zone_info(mem, node);
 
4806
4807	free_percpu(mem->stat);
4808	if (sizeof(struct mem_cgroup) < PAGE_SIZE)
4809		kfree(mem);
4810	else
4811		vfree(mem);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4812}
4813
4814static void mem_cgroup_get(struct mem_cgroup *mem)
 
4815{
4816	atomic_inc(&mem->refcnt);
4817}
 
4818
4819static void __mem_cgroup_put(struct mem_cgroup *mem, int count)
4820{
4821	if (atomic_sub_and_test(count, &mem->refcnt)) {
4822		struct mem_cgroup *parent = parent_mem_cgroup(mem);
4823		__mem_cgroup_free(mem);
4824		if (parent)
4825			mem_cgroup_put(parent);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4826	}
4827}
4828
4829static void mem_cgroup_put(struct mem_cgroup *mem)
4830{
4831	__mem_cgroup_put(mem, 1);
4832}
 
4833
4834/*
4835 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
4836 */
4837static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem)
4838{
4839	if (!mem->res.parent)
4840		return NULL;
4841	return mem_cgroup_from_res_counter(mem->res.parent, res);
4842}
4843
4844#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4845static void __init enable_swap_cgroup(void)
4846{
4847	if (!mem_cgroup_disabled() && really_do_swap_account)
4848		do_swap_account = 1;
4849}
4850#else
4851static void __init enable_swap_cgroup(void)
4852{
4853}
4854#endif
4855
4856static int mem_cgroup_soft_limit_tree_init(void)
 
4857{
4858	struct mem_cgroup_tree_per_node *rtpn;
4859	struct mem_cgroup_tree_per_zone *rtpz;
4860	int tmp, node, zone;
4861
4862	for_each_node_state(node, N_POSSIBLE) {
4863		tmp = node;
4864		if (!node_state(node, N_NORMAL_MEMORY))
4865			tmp = -1;
4866		rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
4867		if (!rtpn)
4868			return 1;
4869
4870		soft_limit_tree.rb_tree_per_node[node] = rtpn;
4871
4872		for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4873			rtpz = &rtpn->rb_tree_per_zone[zone];
4874			rtpz->rb_root = RB_ROOT;
4875			spin_lock_init(&rtpz->lock);
4876		}
4877	}
4878	return 0;
4879}
4880
4881static struct cgroup_subsys_state * __ref
4882mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
4883{
4884	struct mem_cgroup *mem, *parent;
4885	long error = -ENOMEM;
4886	int node;
4887
4888	mem = mem_cgroup_alloc();
4889	if (!mem)
4890		return ERR_PTR(error);
4891
4892	for_each_node_state(node, N_POSSIBLE)
4893		if (alloc_mem_cgroup_per_zone_info(mem, node))
4894			goto free_out;
4895
4896	/* root ? */
4897	if (cont->parent == NULL) {
4898		int cpu;
4899		enable_swap_cgroup();
4900		parent = NULL;
4901		root_mem_cgroup = mem;
4902		if (mem_cgroup_soft_limit_tree_init())
4903			goto free_out;
4904		for_each_possible_cpu(cpu) {
4905			struct memcg_stock_pcp *stock =
4906						&per_cpu(memcg_stock, cpu);
4907			INIT_WORK(&stock->work, drain_local_stock);
4908		}
4909		hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
4910	} else {
4911		parent = mem_cgroup_from_cont(cont->parent);
4912		mem->use_hierarchy = parent->use_hierarchy;
4913		mem->oom_kill_disable = parent->oom_kill_disable;
4914	}
4915
4916	if (parent && parent->use_hierarchy) {
4917		res_counter_init(&mem->res, &parent->res);
4918		res_counter_init(&mem->memsw, &parent->memsw);
4919		/*
4920		 * We increment refcnt of the parent to ensure that we can
4921		 * safely access it on res_counter_charge/uncharge.
4922		 * This refcnt will be decremented when freeing this
4923		 * mem_cgroup(see mem_cgroup_put).
4924		 */
4925		mem_cgroup_get(parent);
4926	} else {
4927		res_counter_init(&mem->res, NULL);
4928		res_counter_init(&mem->memsw, NULL);
4929	}
4930	mem->last_scanned_child = 0;
4931	mem->last_scanned_node = MAX_NUMNODES;
4932	INIT_LIST_HEAD(&mem->oom_notify);
4933
4934	if (parent)
4935		mem->swappiness = mem_cgroup_swappiness(parent);
4936	atomic_set(&mem->refcnt, 1);
4937	mem->move_charge_at_immigrate = 0;
4938	mutex_init(&mem->thresholds_lock);
4939	return &mem->css;
4940free_out:
4941	__mem_cgroup_free(mem);
4942	root_mem_cgroup = NULL;
4943	return ERR_PTR(error);
4944}
4945
4946static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
4947					struct cgroup *cont)
4948{
4949	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
4950
4951	return mem_cgroup_force_empty(mem, false);
4952}
4953
4954static void mem_cgroup_destroy(struct cgroup_subsys *ss,
4955				struct cgroup *cont)
4956{
4957	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
 
 
 
 
 
 
4958
4959	mem_cgroup_put(mem);
 
 
 
 
4960}
4961
4962static int mem_cgroup_populate(struct cgroup_subsys *ss,
4963				struct cgroup *cont)
 
 
 
 
 
 
 
 
 
 
 
 
4964{
4965	int ret;
4966
4967	ret = cgroup_add_files(cont, ss, mem_cgroup_files,
4968				ARRAY_SIZE(mem_cgroup_files));
4969
4970	if (!ret)
4971		ret = register_memsw_files(cont, ss);
4972	return ret;
 
 
 
 
 
 
4973}
4974
4975#ifdef CONFIG_MMU
4976/* Handlers for move charge at task migration. */
4977#define PRECHARGE_COUNT_AT_ONCE	256
4978static int mem_cgroup_do_precharge(unsigned long count)
4979{
4980	int ret = 0;
4981	int batch_count = PRECHARGE_COUNT_AT_ONCE;
4982	struct mem_cgroup *mem = mc.to;
4983
4984	if (mem_cgroup_is_root(mem)) {
4985		mc.precharge += count;
4986		/* we don't need css_get for root */
4987		return ret;
4988	}
4989	/* try to charge at once */
4990	if (count > 1) {
4991		struct res_counter *dummy;
4992		/*
4993		 * "mem" cannot be under rmdir() because we've already checked
4994		 * by cgroup_lock_live_cgroup() that it is not removed and we
4995		 * are still under the same cgroup_mutex. So we can postpone
4996		 * css_get().
4997		 */
4998		if (res_counter_charge(&mem->res, PAGE_SIZE * count, &dummy))
4999			goto one_by_one;
5000		if (do_swap_account && res_counter_charge(&mem->memsw,
5001						PAGE_SIZE * count, &dummy)) {
5002			res_counter_uncharge(&mem->res, PAGE_SIZE * count);
5003			goto one_by_one;
5004		}
5005		mc.precharge += count;
5006		return ret;
5007	}
5008one_by_one:
5009	/* fall back to one by one charge */
5010	while (count--) {
5011		if (signal_pending(current)) {
5012			ret = -EINTR;
5013			break;
5014		}
5015		if (!batch_count--) {
5016			batch_count = PRECHARGE_COUNT_AT_ONCE;
5017			cond_resched();
5018		}
5019		ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, 1, &mem, false);
5020		if (ret || !mem)
5021			/* mem_cgroup_clear_mc() will do uncharge later */
5022			return -ENOMEM;
5023		mc.precharge++;
 
5024	}
5025	return ret;
5026}
5027
5028/**
5029 * is_target_pte_for_mc - check a pte whether it is valid for move charge
5030 * @vma: the vma the pte to be checked belongs
5031 * @addr: the address corresponding to the pte to be checked
5032 * @ptent: the pte to be checked
5033 * @target: the pointer the target page or swap ent will be stored(can be NULL)
5034 *
5035 * Returns
5036 *   0(MC_TARGET_NONE): if the pte is not a target for move charge.
5037 *   1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
5038 *     move charge. if @target is not NULL, the page is stored in target->page
5039 *     with extra refcnt got(Callers should handle it).
5040 *   2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
5041 *     target for charge migration. if @target is not NULL, the entry is stored
5042 *     in target->ent.
5043 *
5044 * Called with pte lock held.
5045 */
5046union mc_target {
5047	struct page	*page;
5048	swp_entry_t	ent;
5049};
5050
5051enum mc_target_type {
5052	MC_TARGET_NONE,	/* not used */
5053	MC_TARGET_PAGE,
5054	MC_TARGET_SWAP,
5055};
5056
5057static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
5058						unsigned long addr, pte_t ptent)
5059{
5060	struct page *page = vm_normal_page(vma, addr, ptent);
5061
5062	if (!page || !page_mapped(page))
5063		return NULL;
5064	if (PageAnon(page)) {
5065		/* we don't move shared anon */
5066		if (!move_anon() || page_mapcount(page) > 2)
5067			return NULL;
5068	} else if (!move_file())
5069		/* we ignore mapcount for file pages */
5070		return NULL;
 
5071	if (!get_page_unless_zero(page))
5072		return NULL;
5073
5074	return page;
5075}
5076
 
5077static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5078			unsigned long addr, pte_t ptent, swp_entry_t *entry)
5079{
5080	int usage_count;
5081	struct page *page = NULL;
5082	swp_entry_t ent = pte_to_swp_entry(ptent);
5083
5084	if (!move_anon() || non_swap_entry(ent))
5085		return NULL;
5086	usage_count = mem_cgroup_count_swap_user(ent, &page);
5087	if (usage_count > 1) { /* we don't move shared anon */
5088		if (page)
5089			put_page(page);
5090		return NULL;
5091	}
5092	if (do_swap_account)
 
 
 
 
5093		entry->val = ent.val;
5094
5095	return page;
5096}
 
 
 
 
 
 
 
5097
5098static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
5099			unsigned long addr, pte_t ptent, swp_entry_t *entry)
5100{
5101	struct page *page = NULL;
5102	struct inode *inode;
5103	struct address_space *mapping;
5104	pgoff_t pgoff;
5105
5106	if (!vma->vm_file) /* anonymous vma */
5107		return NULL;
5108	if (!move_file())
5109		return NULL;
5110
5111	inode = vma->vm_file->f_path.dentry->d_inode;
5112	mapping = vma->vm_file->f_mapping;
5113	if (pte_none(ptent))
5114		pgoff = linear_page_index(vma, addr);
5115	else /* pte_file(ptent) is true */
5116		pgoff = pte_to_pgoff(ptent);
5117
5118	/* page is moved even if it's not RSS of this task(page-faulted). */
5119	page = find_get_page(mapping, pgoff);
5120
5121#ifdef CONFIG_SWAP
5122	/* shmem/tmpfs may report page out on swap: account for that too. */
5123	if (radix_tree_exceptional_entry(page)) {
5124		swp_entry_t swap = radix_to_swp_entry(page);
5125		if (do_swap_account)
5126			*entry = swap;
5127		page = find_get_page(&swapper_space, swap.val);
5128	}
 
 
 
 
 
 
5129#endif
5130	return page;
5131}
5132
5133static int is_target_pte_for_mc(struct vm_area_struct *vma,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5134		unsigned long addr, pte_t ptent, union mc_target *target)
5135{
5136	struct page *page = NULL;
5137	struct page_cgroup *pc;
5138	int ret = 0;
5139	swp_entry_t ent = { .val = 0 };
5140
5141	if (pte_present(ptent))
5142		page = mc_handle_present_pte(vma, addr, ptent);
5143	else if (is_swap_pte(ptent))
5144		page = mc_handle_swap_pte(vma, addr, ptent, &ent);
5145	else if (pte_none(ptent) || pte_file(ptent))
5146		page = mc_handle_file_pte(vma, addr, ptent, &ent);
5147
5148	if (!page && !ent.val)
5149		return 0;
5150	if (page) {
5151		pc = lookup_page_cgroup(page);
5152		/*
5153		 * Do only loose check w/o page_cgroup lock.
5154		 * mem_cgroup_move_account() checks the pc is valid or not under
5155		 * the lock.
5156		 */
5157		if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
5158			ret = MC_TARGET_PAGE;
5159			if (target)
5160				target->page = page;
5161		}
5162		if (!ret || !target)
5163			put_page(page);
5164	}
5165	/* There is a swap entry and a page doesn't exist or isn't charged */
5166	if (ent.val && !ret &&
5167			css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
5168		ret = MC_TARGET_SWAP;
5169		if (target)
5170			target->ent = ent;
5171	}
5172	return ret;
5173}
5174
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5175static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
5176					unsigned long addr, unsigned long end,
5177					struct mm_walk *walk)
5178{
5179	struct vm_area_struct *vma = walk->private;
5180	pte_t *pte;
5181	spinlock_t *ptl;
5182
5183	split_huge_page_pmd(walk->mm, pmd);
 
 
 
 
 
 
5184
 
 
5185	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5186	for (; addr != end; pte++, addr += PAGE_SIZE)
5187		if (is_target_pte_for_mc(vma, addr, *pte, NULL))
5188			mc.precharge++;	/* increment precharge temporarily */
5189	pte_unmap_unlock(pte - 1, ptl);
5190	cond_resched();
5191
5192	return 0;
5193}
5194
5195static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
5196{
5197	unsigned long precharge;
5198	struct vm_area_struct *vma;
5199
 
 
 
 
5200	down_read(&mm->mmap_sem);
5201	for (vma = mm->mmap; vma; vma = vma->vm_next) {
5202		struct mm_walk mem_cgroup_count_precharge_walk = {
5203			.pmd_entry = mem_cgroup_count_precharge_pte_range,
5204			.mm = mm,
5205			.private = vma,
5206		};
5207		if (is_vm_hugetlb_page(vma))
5208			continue;
5209		walk_page_range(vma->vm_start, vma->vm_end,
5210					&mem_cgroup_count_precharge_walk);
5211	}
5212	up_read(&mm->mmap_sem);
5213
5214	precharge = mc.precharge;
5215	mc.precharge = 0;
5216
5217	return precharge;
5218}
5219
5220static int mem_cgroup_precharge_mc(struct mm_struct *mm)
5221{
5222	unsigned long precharge = mem_cgroup_count_precharge(mm);
5223
5224	VM_BUG_ON(mc.moving_task);
5225	mc.moving_task = current;
5226	return mem_cgroup_do_precharge(precharge);
5227}
5228
5229/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
5230static void __mem_cgroup_clear_mc(void)
5231{
5232	struct mem_cgroup *from = mc.from;
5233	struct mem_cgroup *to = mc.to;
5234
5235	/* we must uncharge all the leftover precharges from mc.to */
5236	if (mc.precharge) {
5237		__mem_cgroup_cancel_charge(mc.to, mc.precharge);
5238		mc.precharge = 0;
5239	}
5240	/*
5241	 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
5242	 * we must uncharge here.
5243	 */
5244	if (mc.moved_charge) {
5245		__mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
5246		mc.moved_charge = 0;
5247	}
5248	/* we must fixup refcnts and charges */
5249	if (mc.moved_swap) {
5250		/* uncharge swap account from the old cgroup */
5251		if (!mem_cgroup_is_root(mc.from))
5252			res_counter_uncharge(&mc.from->memsw,
5253						PAGE_SIZE * mc.moved_swap);
5254		__mem_cgroup_put(mc.from, mc.moved_swap);
5255
5256		if (!mem_cgroup_is_root(mc.to)) {
5257			/*
5258			 * we charged both to->res and to->memsw, so we should
5259			 * uncharge to->res.
5260			 */
5261			res_counter_uncharge(&mc.to->res,
5262						PAGE_SIZE * mc.moved_swap);
5263		}
5264		/* we've already done mem_cgroup_get(mc.to) */
 
5265		mc.moved_swap = 0;
5266	}
5267	memcg_oom_recover(from);
5268	memcg_oom_recover(to);
5269	wake_up_all(&mc.waitq);
5270}
5271
5272static void mem_cgroup_clear_mc(void)
5273{
5274	struct mem_cgroup *from = mc.from;
5275
5276	/*
5277	 * we must clear moving_task before waking up waiters at the end of
5278	 * task migration.
5279	 */
5280	mc.moving_task = NULL;
5281	__mem_cgroup_clear_mc();
5282	spin_lock(&mc.lock);
5283	mc.from = NULL;
5284	mc.to = NULL;
 
5285	spin_unlock(&mc.lock);
5286	mem_cgroup_end_move(from);
 
5287}
5288
5289static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
5290				struct cgroup *cgroup,
5291				struct task_struct *p)
5292{
 
 
 
 
 
 
5293	int ret = 0;
5294	struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup);
5295
5296	if (mem->move_charge_at_immigrate) {
5297		struct mm_struct *mm;
5298		struct mem_cgroup *from = mem_cgroup_from_task(p);
5299
5300		VM_BUG_ON(from == mem);
 
 
 
 
 
 
 
 
 
 
 
 
 
5301
5302		mm = get_task_mm(p);
5303		if (!mm)
5304			return 0;
5305		/* We move charges only when we move a owner of the mm */
5306		if (mm->owner == p) {
5307			VM_BUG_ON(mc.from);
5308			VM_BUG_ON(mc.to);
5309			VM_BUG_ON(mc.precharge);
5310			VM_BUG_ON(mc.moved_charge);
5311			VM_BUG_ON(mc.moved_swap);
5312			mem_cgroup_start_move(from);
5313			spin_lock(&mc.lock);
5314			mc.from = from;
5315			mc.to = mem;
5316			spin_unlock(&mc.lock);
5317			/* We set mc.moving_task later */
5318
5319			ret = mem_cgroup_precharge_mc(mm);
5320			if (ret)
5321				mem_cgroup_clear_mc();
5322		}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5323		mmput(mm);
5324	}
5325	return ret;
5326}
5327
5328static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
5329				struct cgroup *cgroup,
5330				struct task_struct *p)
5331{
5332	mem_cgroup_clear_mc();
 
5333}
5334
5335static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
5336				unsigned long addr, unsigned long end,
5337				struct mm_walk *walk)
5338{
5339	int ret = 0;
5340	struct vm_area_struct *vma = walk->private;
5341	pte_t *pte;
5342	spinlock_t *ptl;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5343
5344	split_huge_page_pmd(walk->mm, pmd);
 
5345retry:
5346	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5347	for (; addr != end; addr += PAGE_SIZE) {
5348		pte_t ptent = *(pte++);
5349		union mc_target target;
5350		int type;
5351		struct page *page;
5352		struct page_cgroup *pc;
5353		swp_entry_t ent;
5354
5355		if (!mc.precharge)
5356			break;
5357
5358		type = is_target_pte_for_mc(vma, addr, ptent, &target);
5359		switch (type) {
5360		case MC_TARGET_PAGE:
5361			page = target.page;
 
 
 
 
 
 
 
 
5362			if (isolate_lru_page(page))
5363				goto put;
5364			pc = lookup_page_cgroup(page);
5365			if (!mem_cgroup_move_account(page, 1, pc,
5366						     mc.from, mc.to, false)) {
5367				mc.precharge--;
5368				/* we uncharge from mc.from later. */
5369				mc.moved_charge++;
5370			}
5371			putback_lru_page(page);
5372put:			/* is_target_pte_for_mc() gets the page */
5373			put_page(page);
5374			break;
5375		case MC_TARGET_SWAP:
5376			ent = target.ent;
5377			if (!mem_cgroup_move_swap_account(ent,
5378						mc.from, mc.to, false)) {
5379				mc.precharge--;
5380				/* we fixup refcnts and charges later. */
5381				mc.moved_swap++;
5382			}
5383			break;
5384		default:
5385			break;
5386		}
5387	}
5388	pte_unmap_unlock(pte - 1, ptl);
5389	cond_resched();
5390
5391	if (addr != end) {
5392		/*
5393		 * We have consumed all precharges we got in can_attach().
5394		 * We try charge one by one, but don't do any additional
5395		 * charges to mc.to if we have failed in charge once in attach()
5396		 * phase.
5397		 */
5398		ret = mem_cgroup_do_precharge(1);
5399		if (!ret)
5400			goto retry;
5401	}
5402
5403	return ret;
5404}
5405
5406static void mem_cgroup_move_charge(struct mm_struct *mm)
5407{
5408	struct vm_area_struct *vma;
 
 
 
5409
5410	lru_add_drain_all();
 
 
 
 
 
 
 
5411retry:
5412	if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
5413		/*
5414		 * Someone who are holding the mmap_sem might be waiting in
5415		 * waitq. So we cancel all extra charges, wake up all waiters,
5416		 * and retry. Because we cancel precharges, we might not be able
5417		 * to move enough charges, but moving charge is a best-effort
5418		 * feature anyway, so it wouldn't be a big problem.
5419		 */
5420		__mem_cgroup_clear_mc();
5421		cond_resched();
5422		goto retry;
5423	}
5424	for (vma = mm->mmap; vma; vma = vma->vm_next) {
5425		int ret;
5426		struct mm_walk mem_cgroup_move_charge_walk = {
5427			.pmd_entry = mem_cgroup_move_charge_pte_range,
5428			.mm = mm,
5429			.private = vma,
5430		};
5431		if (is_vm_hugetlb_page(vma))
5432			continue;
5433		ret = walk_page_range(vma->vm_start, vma->vm_end,
5434						&mem_cgroup_move_charge_walk);
5435		if (ret)
5436			/*
5437			 * means we have consumed all precharges and failed in
5438			 * doing additional charge. Just abandon here.
5439			 */
5440			break;
5441	}
5442	up_read(&mm->mmap_sem);
5443}
5444
5445static void mem_cgroup_move_task(struct cgroup_subsys *ss,
5446				struct cgroup *cont,
5447				struct cgroup *old_cont,
5448				struct task_struct *p)
5449{
5450	struct mm_struct *mm = get_task_mm(p);
5451
5452	if (mm) {
5453		if (mc.to)
5454			mem_cgroup_move_charge(mm);
5455		put_swap_token(mm);
5456		mmput(mm);
5457	}
5458	if (mc.to)
5459		mem_cgroup_clear_mc();
 
5460}
5461#else	/* !CONFIG_MMU */
5462static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
5463				struct cgroup *cgroup,
5464				struct task_struct *p)
5465{
5466	return 0;
5467}
5468static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
5469				struct cgroup *cgroup,
5470				struct task_struct *p)
5471{
5472}
5473static void mem_cgroup_move_task(struct cgroup_subsys *ss,
5474				struct cgroup *cont,
5475				struct cgroup *old_cont,
5476				struct task_struct *p)
5477{
5478}
5479#endif
5480
5481struct cgroup_subsys mem_cgroup_subsys = {
5482	.name = "memory",
5483	.subsys_id = mem_cgroup_subsys_id,
5484	.create = mem_cgroup_create,
5485	.pre_destroy = mem_cgroup_pre_destroy,
5486	.destroy = mem_cgroup_destroy,
5487	.populate = mem_cgroup_populate,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5488	.can_attach = mem_cgroup_can_attach,
5489	.cancel_attach = mem_cgroup_cancel_attach,
5490	.attach = mem_cgroup_move_task,
 
 
 
5491	.early_init = 0,
5492	.use_id = 1,
5493};
5494
5495#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5496static int __init enable_swap_account(char *s)
5497{
5498	/* consider enabled if no parameter or 1 is given */
5499	if (!strcmp(s, "1"))
5500		really_do_swap_account = 1;
5501	else if (!strcmp(s, "0"))
5502		really_do_swap_account = 0;
5503	return 1;
5504}
5505__setup("swapaccount=", enable_swap_account);
5506
5507#endif