diff options
Diffstat (limited to 'kernel/mm/memcontrol.c')
| -rw-r--r-- | kernel/mm/memcontrol.c | 5933 |
1 files changed, 5933 insertions, 0 deletions
diff --git a/kernel/mm/memcontrol.c b/kernel/mm/memcontrol.c new file mode 100644 index 000000000..8bd68b5ec --- /dev/null +++ b/kernel/mm/memcontrol.c @@ -0,0 +1,5933 @@ +/* memcontrol.c - Memory Controller + * + * Copyright IBM Corporation, 2007 + * Author Balbir Singh <balbir@linux.vnet.ibm.com> + * + * Copyright 2007 OpenVZ SWsoft Inc + * Author: Pavel Emelianov <xemul@openvz.org> + * + * Memory thresholds + * Copyright (C) 2009 Nokia Corporation + * Author: Kirill A. Shutemov + * + * Kernel Memory Controller + * Copyright (C) 2012 Parallels Inc. and Google Inc. + * Authors: Glauber Costa and Suleiman Souhlal + * + * Native page reclaim + * Charge lifetime sanitation + * Lockless page tracking & accounting + * Unified hierarchy configuration model + * Copyright (C) 2015 Red Hat, Inc., Johannes Weiner + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/page_counter.h> +#include <linux/memcontrol.h> +#include <linux/cgroup.h> +#include <linux/mm.h> +#include <linux/hugetlb.h> +#include <linux/pagemap.h> +#include <linux/smp.h> +#include <linux/page-flags.h> +#include <linux/backing-dev.h> +#include <linux/bit_spinlock.h> +#include <linux/rcupdate.h> +#include <linux/limits.h> +#include <linux/export.h> +#include <linux/mutex.h> +#include <linux/rbtree.h> +#include <linux/slab.h> +#include <linux/swap.h> +#include <linux/swapops.h> +#include <linux/spinlock.h> +#include <linux/eventfd.h> +#include <linux/poll.h> +#include <linux/sort.h> +#include <linux/fs.h> +#include <linux/seq_file.h> +#include <linux/vmpressure.h> +#include <linux/mm_inline.h> +#include <linux/swap_cgroup.h> +#include <linux/cpu.h> +#include <linux/oom.h> +#include <linux/lockdep.h> +#include <linux/file.h> +#include "internal.h" +#include <net/sock.h> +#include <net/ip.h> +#include <net/tcp_memcontrol.h> +#include <linux/locallock.h> + +#include "slab.h" + +#include <asm/uaccess.h> + +#include <trace/events/vmscan.h> + +struct cgroup_subsys memory_cgrp_subsys __read_mostly; +EXPORT_SYMBOL(memory_cgrp_subsys); + +#define MEM_CGROUP_RECLAIM_RETRIES 5 +static struct mem_cgroup *root_mem_cgroup __read_mostly; + +/* Whether the swap controller is active */ +#ifdef CONFIG_MEMCG_SWAP +int do_swap_account __read_mostly; +#else +#define do_swap_account 0 +#endif + +static DEFINE_LOCAL_IRQ_LOCK(event_lock); +static const char * const mem_cgroup_stat_names[] = { + "cache", + "rss", + "rss_huge", + "mapped_file", + "writeback", + "swap", +}; + +static const char * const mem_cgroup_events_names[] = { + "pgpgin", + "pgpgout", + "pgfault", + "pgmajfault", +}; + +static const char * const mem_cgroup_lru_names[] = { + "inactive_anon", + "active_anon", + "inactive_file", + "active_file", + "unevictable", +}; + +/* + * Per memcg event counter is incremented at every pagein/pageout. With THP, + * it will be incremated by the number of pages. This counter is used for + * for trigger some periodic events. This is straightforward and better + * than using jiffies etc. to handle periodic memcg event. + */ +enum mem_cgroup_events_target { + MEM_CGROUP_TARGET_THRESH, + MEM_CGROUP_TARGET_SOFTLIMIT, + MEM_CGROUP_TARGET_NUMAINFO, + MEM_CGROUP_NTARGETS, +}; +#define THRESHOLDS_EVENTS_TARGET 128 +#define SOFTLIMIT_EVENTS_TARGET 1024 +#define NUMAINFO_EVENTS_TARGET 1024 + +struct mem_cgroup_stat_cpu { + long count[MEM_CGROUP_STAT_NSTATS]; + unsigned long events[MEMCG_NR_EVENTS]; + unsigned long nr_page_events; + unsigned long targets[MEM_CGROUP_NTARGETS]; +}; + +struct reclaim_iter { + struct mem_cgroup *position; + /* scan generation, increased every round-trip */ + unsigned int generation; +}; + +/* + * per-zone information in memory controller. + */ +struct mem_cgroup_per_zone { + struct lruvec lruvec; + unsigned long lru_size[NR_LRU_LISTS]; + + struct reclaim_iter iter[DEF_PRIORITY + 1]; + + struct rb_node tree_node; /* RB tree node */ + unsigned long usage_in_excess;/* Set to the value by which */ + /* the soft limit is exceeded*/ + bool on_tree; + struct mem_cgroup *memcg; /* Back pointer, we cannot */ + /* use container_of */ +}; + +struct mem_cgroup_per_node { + struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; +}; + +/* + * Cgroups above their limits are maintained in a RB-Tree, independent of + * their hierarchy representation + */ + +struct mem_cgroup_tree_per_zone { + struct rb_root rb_root; + spinlock_t lock; +}; + +struct mem_cgroup_tree_per_node { + struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES]; +}; + +struct mem_cgroup_tree { + struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES]; +}; + +static struct mem_cgroup_tree soft_limit_tree __read_mostly; + +struct mem_cgroup_threshold { + struct eventfd_ctx *eventfd; + unsigned long threshold; +}; + +/* For threshold */ +struct mem_cgroup_threshold_ary { + /* An array index points to threshold just below or equal to usage. */ + int current_threshold; + /* Size of entries[] */ + unsigned int size; + /* Array of thresholds */ + struct mem_cgroup_threshold entries[0]; +}; + +struct mem_cgroup_thresholds { + /* Primary thresholds array */ + struct mem_cgroup_threshold_ary *primary; + /* + * Spare threshold array. + * This is needed to make mem_cgroup_unregister_event() "never fail". + * It must be able to store at least primary->size - 1 entries. + */ + struct mem_cgroup_threshold_ary *spare; +}; + +/* for OOM */ +struct mem_cgroup_eventfd_list { + struct list_head list; + struct eventfd_ctx *eventfd; +}; + +/* + * cgroup_event represents events which userspace want to receive. + */ +struct mem_cgroup_event { + /* + * memcg which the event belongs to. + */ + struct mem_cgroup *memcg; + /* + * eventfd to signal userspace about the event. + */ + struct eventfd_ctx *eventfd; + /* + * Each of these stored in a list by the cgroup. + */ + struct list_head list; + /* + * register_event() callback will be used to add new userspace + * waiter for changes related to this event. Use eventfd_signal() + * on eventfd to send notification to userspace. + */ + int (*register_event)(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd, const char *args); + /* + * unregister_event() callback will be called when userspace closes + * the eventfd or on cgroup removing. This callback must be set, + * if you want provide notification functionality. + */ + void (*unregister_event)(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd); + /* + * All fields below needed to unregister event when + * userspace closes eventfd. + */ + poll_table pt; + wait_queue_head_t *wqh; + wait_queue_t wait; + struct work_struct remove; +}; + +static void mem_cgroup_threshold(struct mem_cgroup *memcg); +static void mem_cgroup_oom_notify(struct mem_cgroup *memcg); + +/* + * The memory controller data structure. The memory controller controls both + * page cache and RSS per cgroup. We would eventually like to provide + * statistics based on the statistics developed by Rik Van Riel for clock-pro, + * to help the administrator determine what knobs to tune. + */ +struct mem_cgroup { + struct cgroup_subsys_state css; + + /* Accounted resources */ + struct page_counter memory; + struct page_counter memsw; + struct page_counter kmem; + + /* Normal memory consumption range */ + unsigned long low; + unsigned long high; + + unsigned long soft_limit; + + /* vmpressure notifications */ + struct vmpressure vmpressure; + + /* css_online() has been completed */ + int initialized; + + /* + * Should the accounting and control be hierarchical, per subtree? + */ + bool use_hierarchy; + + bool oom_lock; + atomic_t under_oom; + atomic_t oom_wakeups; + + int swappiness; + /* OOM-Killer disable */ + int oom_kill_disable; + + /* protect arrays of thresholds */ + struct mutex thresholds_lock; + + /* thresholds for memory usage. RCU-protected */ + struct mem_cgroup_thresholds thresholds; + + /* thresholds for mem+swap usage. RCU-protected */ + struct mem_cgroup_thresholds memsw_thresholds; + + /* For oom notifier event fd */ + struct list_head oom_notify; + + /* + * Should we move charges of a task when a task is moved into this + * mem_cgroup ? And what type of charges should we move ? + */ + unsigned long move_charge_at_immigrate; + /* + * set > 0 if pages under this cgroup are moving to other cgroup. + */ + atomic_t moving_account; + /* taken only while moving_account > 0 */ + spinlock_t move_lock; + struct task_struct *move_lock_task; + unsigned long move_lock_flags; + /* + * percpu counter. + */ + struct mem_cgroup_stat_cpu __percpu *stat; + /* + * used when a cpu is offlined or other synchronizations + * See mem_cgroup_read_stat(). + */ + struct mem_cgroup_stat_cpu nocpu_base; + spinlock_t pcp_counter_lock; + +#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET) + struct cg_proto tcp_mem; +#endif +#if defined(CONFIG_MEMCG_KMEM) + /* Index in the kmem_cache->memcg_params.memcg_caches array */ + int kmemcg_id; + bool kmem_acct_activated; + bool kmem_acct_active; +#endif + + int last_scanned_node; +#if MAX_NUMNODES > 1 + nodemask_t scan_nodes; + atomic_t numainfo_events; + atomic_t numainfo_updating; +#endif + + /* List of events which userspace want to receive */ + struct list_head event_list; + spinlock_t event_list_lock; + + struct mem_cgroup_per_node *nodeinfo[0]; + /* WARNING: nodeinfo must be the last member here */ +}; + +#ifdef CONFIG_MEMCG_KMEM +bool memcg_kmem_is_active(struct mem_cgroup *memcg) +{ + return memcg->kmem_acct_active; +} +#endif + +/* Stuffs for move charges at task migration. */ +/* + * Types of charges to be moved. + */ +#define MOVE_ANON 0x1U +#define MOVE_FILE 0x2U +#define MOVE_MASK (MOVE_ANON | MOVE_FILE) + +/* "mc" and its members are protected by cgroup_mutex */ +static struct move_charge_struct { + spinlock_t lock; /* for from, to */ + struct mem_cgroup *from; + struct mem_cgroup *to; + unsigned long flags; + unsigned long precharge; + unsigned long moved_charge; + unsigned long moved_swap; + struct task_struct *moving_task; /* a task moving charges */ + wait_queue_head_t waitq; /* a waitq for other context */ +} mc = { + .lock = __SPIN_LOCK_UNLOCKED(mc.lock), + .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq), +}; + +/* + * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft + * limit reclaim to prevent infinite loops, if they ever occur. + */ +#define MEM_CGROUP_MAX_RECLAIM_LOOPS 100 +#define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2 + +enum charge_type { + MEM_CGROUP_CHARGE_TYPE_CACHE = 0, + MEM_CGROUP_CHARGE_TYPE_ANON, + MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */ + MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */ + NR_CHARGE_TYPE, +}; + +/* for encoding cft->private value on file */ +enum res_type { + _MEM, + _MEMSWAP, + _OOM_TYPE, + _KMEM, +}; + +#define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val)) +#define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff) +#define MEMFILE_ATTR(val) ((val) & 0xffff) +/* Used for OOM nofiier */ +#define OOM_CONTROL (0) + +/* + * The memcg_create_mutex will be held whenever a new cgroup is created. + * As a consequence, any change that needs to protect against new child cgroups + * appearing has to hold it as well. + */ +static DEFINE_MUTEX(memcg_create_mutex); + +struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s) +{ + return s ? container_of(s, struct mem_cgroup, css) : NULL; +} + +/* Some nice accessors for the vmpressure. */ +struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg) +{ + if (!memcg) + memcg = root_mem_cgroup; + return &memcg->vmpressure; +} + +struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr) +{ + return &container_of(vmpr, struct mem_cgroup, vmpressure)->css; +} + +static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg) +{ + return (memcg == root_mem_cgroup); +} + +/* + * We restrict the id in the range of [1, 65535], so it can fit into + * an unsigned short. + */ +#define MEM_CGROUP_ID_MAX USHRT_MAX + +static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg) +{ + return memcg->css.id; +} + +/* + * A helper function to get mem_cgroup from ID. must be called under + * rcu_read_lock(). The caller is responsible for calling + * css_tryget_online() if the mem_cgroup is used for charging. (dropping + * refcnt from swap can be called against removed memcg.) + */ +static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id) +{ + struct cgroup_subsys_state *css; + + css = css_from_id(id, &memory_cgrp_subsys); + return mem_cgroup_from_css(css); +} + +/* Writing them here to avoid exposing memcg's inner layout */ +#if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM) + +void sock_update_memcg(struct sock *sk) +{ + if (mem_cgroup_sockets_enabled) { + struct mem_cgroup *memcg; + struct cg_proto *cg_proto; + + BUG_ON(!sk->sk_prot->proto_cgroup); + + /* Socket cloning can throw us here with sk_cgrp already + * filled. It won't however, necessarily happen from + * process context. So the test for root memcg given + * the current task's memcg won't help us in this case. + * + * Respecting the original socket's memcg is a better + * decision in this case. + */ + if (sk->sk_cgrp) { + BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg)); + css_get(&sk->sk_cgrp->memcg->css); + return; + } + + rcu_read_lock(); + memcg = mem_cgroup_from_task(current); + cg_proto = sk->sk_prot->proto_cgroup(memcg); + if (!mem_cgroup_is_root(memcg) && + memcg_proto_active(cg_proto) && + css_tryget_online(&memcg->css)) { + sk->sk_cgrp = cg_proto; + } + rcu_read_unlock(); + } +} +EXPORT_SYMBOL(sock_update_memcg); + +void sock_release_memcg(struct sock *sk) +{ + if (mem_cgroup_sockets_enabled && sk->sk_cgrp) { + struct mem_cgroup *memcg; + WARN_ON(!sk->sk_cgrp->memcg); + memcg = sk->sk_cgrp->memcg; + css_put(&sk->sk_cgrp->memcg->css); + } +} + +struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg) +{ + if (!memcg || mem_cgroup_is_root(memcg)) + return NULL; + + return &memcg->tcp_mem; +} +EXPORT_SYMBOL(tcp_proto_cgroup); + +#endif + +#ifdef CONFIG_MEMCG_KMEM +/* + * This will be the memcg's index in each cache's ->memcg_params.memcg_caches. + * The main reason for not using cgroup id for this: + * this works better in sparse environments, where we have a lot of memcgs, + * but only a few kmem-limited. Or also, if we have, for instance, 200 + * memcgs, and none but the 200th is kmem-limited, we'd have to have a + * 200 entry array for that. + * + * The current size of the caches array is stored in memcg_nr_cache_ids. It + * will double each time we have to increase it. + */ +static DEFINE_IDA(memcg_cache_ida); +int memcg_nr_cache_ids; + +/* Protects memcg_nr_cache_ids */ +static DECLARE_RWSEM(memcg_cache_ids_sem); + +void memcg_get_cache_ids(void) +{ + down_read(&memcg_cache_ids_sem); +} + +void memcg_put_cache_ids(void) +{ + up_read(&memcg_cache_ids_sem); +} + +/* + * MIN_SIZE is different than 1, because we would like to avoid going through + * the alloc/free process all the time. In a small machine, 4 kmem-limited + * cgroups is a reasonable guess. In the future, it could be a parameter or + * tunable, but that is strictly not necessary. + * + * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get + * this constant directly from cgroup, but it is understandable that this is + * better kept as an internal representation in cgroup.c. In any case, the + * cgrp_id space is not getting any smaller, and we don't have to necessarily + * increase ours as well if it increases. + */ +#define MEMCG_CACHES_MIN_SIZE 4 +#define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX + +/* + * A lot of the calls to the cache allocation functions are expected to be + * inlined by the compiler. Since the calls to memcg_kmem_get_cache are + * conditional to this static branch, we'll have to allow modules that does + * kmem_cache_alloc and the such to see this symbol as well + */ +struct static_key memcg_kmem_enabled_key; +EXPORT_SYMBOL(memcg_kmem_enabled_key); + +#endif /* CONFIG_MEMCG_KMEM */ + +static struct mem_cgroup_per_zone * +mem_cgroup_zone_zoneinfo(struct mem_cgroup *memcg, struct zone *zone) +{ + int nid = zone_to_nid(zone); + int zid = zone_idx(zone); + + return &memcg->nodeinfo[nid]->zoneinfo[zid]; +} + +struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg) +{ + return &memcg->css; +} + +static struct mem_cgroup_per_zone * +mem_cgroup_page_zoneinfo(struct mem_cgroup *memcg, struct page *page) +{ + int nid = page_to_nid(page); + int zid = page_zonenum(page); + + return &memcg->nodeinfo[nid]->zoneinfo[zid]; +} + +static struct mem_cgroup_tree_per_zone * +soft_limit_tree_node_zone(int nid, int zid) +{ + return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; +} + +static struct mem_cgroup_tree_per_zone * +soft_limit_tree_from_page(struct page *page) +{ + int nid = page_to_nid(page); + int zid = page_zonenum(page); + + return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; +} + +static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_zone *mz, + struct mem_cgroup_tree_per_zone *mctz, + unsigned long new_usage_in_excess) +{ + struct rb_node **p = &mctz->rb_root.rb_node; + struct rb_node *parent = NULL; + struct mem_cgroup_per_zone *mz_node; + + if (mz->on_tree) + return; + + mz->usage_in_excess = new_usage_in_excess; + if (!mz->usage_in_excess) + return; + while (*p) { + parent = *p; + mz_node = rb_entry(parent, struct mem_cgroup_per_zone, + tree_node); + if (mz->usage_in_excess < mz_node->usage_in_excess) + p = &(*p)->rb_left; + /* + * We can't avoid mem cgroups that are over their soft + * limit by the same amount + */ + else if (mz->usage_in_excess >= mz_node->usage_in_excess) + p = &(*p)->rb_right; + } + rb_link_node(&mz->tree_node, parent, p); + rb_insert_color(&mz->tree_node, &mctz->rb_root); + mz->on_tree = true; +} + +static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz, + struct mem_cgroup_tree_per_zone *mctz) +{ + if (!mz->on_tree) + return; + rb_erase(&mz->tree_node, &mctz->rb_root); + mz->on_tree = false; +} + +static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz, + struct mem_cgroup_tree_per_zone *mctz) +{ + unsigned long flags; + + spin_lock_irqsave(&mctz->lock, flags); + __mem_cgroup_remove_exceeded(mz, mctz); + spin_unlock_irqrestore(&mctz->lock, flags); +} + +static unsigned long soft_limit_excess(struct mem_cgroup *memcg) +{ + unsigned long nr_pages = page_counter_read(&memcg->memory); + unsigned long soft_limit = READ_ONCE(memcg->soft_limit); + unsigned long excess = 0; + + if (nr_pages > soft_limit) + excess = nr_pages - soft_limit; + + return excess; +} + +static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page) +{ + unsigned long excess; + struct mem_cgroup_per_zone *mz; + struct mem_cgroup_tree_per_zone *mctz; + + mctz = soft_limit_tree_from_page(page); + /* + * Necessary to update all ancestors when hierarchy is used. + * because their event counter is not touched. + */ + for (; memcg; memcg = parent_mem_cgroup(memcg)) { + mz = mem_cgroup_page_zoneinfo(memcg, page); + excess = soft_limit_excess(memcg); + /* + * We have to update the tree if mz is on RB-tree or + * mem is over its softlimit. + */ + if (excess || mz->on_tree) { + unsigned long flags; + + spin_lock_irqsave(&mctz->lock, flags); + /* if on-tree, remove it */ + if (mz->on_tree) + __mem_cgroup_remove_exceeded(mz, mctz); + /* + * Insert again. mz->usage_in_excess will be updated. + * If excess is 0, no tree ops. + */ + __mem_cgroup_insert_exceeded(mz, mctz, excess); + spin_unlock_irqrestore(&mctz->lock, flags); + } + } +} + +static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg) +{ + struct mem_cgroup_tree_per_zone *mctz; + struct mem_cgroup_per_zone *mz; + int nid, zid; + + for_each_node(nid) { + for (zid = 0; zid < MAX_NR_ZONES; zid++) { + mz = &memcg->nodeinfo[nid]->zoneinfo[zid]; + mctz = soft_limit_tree_node_zone(nid, zid); + mem_cgroup_remove_exceeded(mz, mctz); + } + } +} + +static struct mem_cgroup_per_zone * +__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) +{ + struct rb_node *rightmost = NULL; + struct mem_cgroup_per_zone *mz; + +retry: + mz = NULL; + rightmost = rb_last(&mctz->rb_root); + if (!rightmost) + goto done; /* Nothing to reclaim from */ + + mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node); + /* + * Remove the node now but someone else can add it back, + * we will to add it back at the end of reclaim to its correct + * position in the tree. + */ + __mem_cgroup_remove_exceeded(mz, mctz); + if (!soft_limit_excess(mz->memcg) || + !css_tryget_online(&mz->memcg->css)) + goto retry; +done: + return mz; +} + +static struct mem_cgroup_per_zone * +mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) +{ + struct mem_cgroup_per_zone *mz; + + spin_lock_irq(&mctz->lock); + mz = __mem_cgroup_largest_soft_limit_node(mctz); + spin_unlock_irq(&mctz->lock); + return mz; +} + +/* + * Implementation Note: reading percpu statistics for memcg. + * + * Both of vmstat[] and percpu_counter has threshold and do periodic + * synchronization to implement "quick" read. There are trade-off between + * reading cost and precision of value. Then, we may have a chance to implement + * a periodic synchronizion of counter in memcg's counter. + * + * But this _read() function is used for user interface now. The user accounts + * memory usage by memory cgroup and he _always_ requires exact value because + * he accounts memory. Even if we provide quick-and-fuzzy read, we always + * have to visit all online cpus and make sum. So, for now, unnecessary + * synchronization is not implemented. (just implemented for cpu hotplug) + * + * If there are kernel internal actions which can make use of some not-exact + * value, and reading all cpu value can be performance bottleneck in some + * common workload, threashold and synchonization as vmstat[] should be + * implemented. + */ +static long mem_cgroup_read_stat(struct mem_cgroup *memcg, + enum mem_cgroup_stat_index idx) +{ + long val = 0; + int cpu; + + get_online_cpus(); + for_each_online_cpu(cpu) + val += per_cpu(memcg->stat->count[idx], cpu); +#ifdef CONFIG_HOTPLUG_CPU + spin_lock(&memcg->pcp_counter_lock); + val += memcg->nocpu_base.count[idx]; + spin_unlock(&memcg->pcp_counter_lock); +#endif + put_online_cpus(); + return val; +} + +static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg, + enum mem_cgroup_events_index idx) +{ + unsigned long val = 0; + int cpu; + + get_online_cpus(); + for_each_online_cpu(cpu) + val += per_cpu(memcg->stat->events[idx], cpu); +#ifdef CONFIG_HOTPLUG_CPU + spin_lock(&memcg->pcp_counter_lock); + val += memcg->nocpu_base.events[idx]; + spin_unlock(&memcg->pcp_counter_lock); +#endif + put_online_cpus(); + return val; +} + +static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, + struct page *page, + int nr_pages) +{ + /* + * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is + * counted as CACHE even if it's on ANON LRU. + */ + if (PageAnon(page)) + __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS], + nr_pages); + else + __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE], + nr_pages); + + if (PageTransHuge(page)) + __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], + nr_pages); + + /* pagein of a big page is an event. So, ignore page size */ + if (nr_pages > 0) + __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]); + else { + __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]); + nr_pages = -nr_pages; /* for event */ + } + + __this_cpu_add(memcg->stat->nr_page_events, nr_pages); +} + +unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru) +{ + struct mem_cgroup_per_zone *mz; + + mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec); + return mz->lru_size[lru]; +} + +static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg, + int nid, + unsigned int lru_mask) +{ + unsigned long nr = 0; + int zid; + + VM_BUG_ON((unsigned)nid >= nr_node_ids); + + for (zid = 0; zid < MAX_NR_ZONES; zid++) { + struct mem_cgroup_per_zone *mz; + enum lru_list lru; + + for_each_lru(lru) { + if (!(BIT(lru) & lru_mask)) + continue; + mz = &memcg->nodeinfo[nid]->zoneinfo[zid]; + nr += mz->lru_size[lru]; + } + } + return nr; +} + +static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg, + unsigned int lru_mask) +{ + unsigned long nr = 0; + int nid; + + for_each_node_state(nid, N_MEMORY) + nr += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask); + return nr; +} + +static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, + enum mem_cgroup_events_target target) +{ + unsigned long val, next; + + val = __this_cpu_read(memcg->stat->nr_page_events); + next = __this_cpu_read(memcg->stat->targets[target]); + /* from time_after() in jiffies.h */ + if ((long)next - (long)val < 0) { + switch (target) { + case MEM_CGROUP_TARGET_THRESH: + next = val + THRESHOLDS_EVENTS_TARGET; + break; + case MEM_CGROUP_TARGET_SOFTLIMIT: + next = val + SOFTLIMIT_EVENTS_TARGET; + break; + case MEM_CGROUP_TARGET_NUMAINFO: + next = val + NUMAINFO_EVENTS_TARGET; + break; + default: + break; + } + __this_cpu_write(memcg->stat->targets[target], next); + return true; + } + return false; +} + +/* + * Check events in order. + * + */ +static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) +{ + /* threshold event is triggered in finer grain than soft limit */ + if (unlikely(mem_cgroup_event_ratelimit(memcg, + MEM_CGROUP_TARGET_THRESH))) { + bool do_softlimit; + bool do_numainfo __maybe_unused; + + do_softlimit = mem_cgroup_event_ratelimit(memcg, + MEM_CGROUP_TARGET_SOFTLIMIT); +#if MAX_NUMNODES > 1 + do_numainfo = mem_cgroup_event_ratelimit(memcg, + MEM_CGROUP_TARGET_NUMAINFO); +#endif + mem_cgroup_threshold(memcg); + if (unlikely(do_softlimit)) + mem_cgroup_update_tree(memcg, page); +#if MAX_NUMNODES > 1 + if (unlikely(do_numainfo)) + atomic_inc(&memcg->numainfo_events); +#endif + } +} + +struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) +{ + /* + * mm_update_next_owner() may clear mm->owner to NULL + * if it races with swapoff, page migration, etc. + * So this can be called with p == NULL. + */ + if (unlikely(!p)) + return NULL; + + return mem_cgroup_from_css(task_css(p, memory_cgrp_id)); +} + +static struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) +{ + struct mem_cgroup *memcg = NULL; + + rcu_read_lock(); + do { + /* + * Page cache insertions can happen withou an + * actual mm context, e.g. during disk probing + * on boot, loopback IO, acct() writes etc. + */ + if (unlikely(!mm)) + memcg = root_mem_cgroup; + else { + memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); + if (unlikely(!memcg)) + memcg = root_mem_cgroup; + } + } while (!css_tryget_online(&memcg->css)); + rcu_read_unlock(); + return memcg; +} + +/** + * mem_cgroup_iter - iterate over memory cgroup hierarchy + * @root: hierarchy root + * @prev: previously returned memcg, NULL on first invocation + * @reclaim: cookie for shared reclaim walks, NULL for full walks + * + * Returns references to children of the hierarchy below @root, or + * @root itself, or %NULL after a full round-trip. + * + * Caller must pass the return value in @prev on subsequent + * invocations for reference counting, or use mem_cgroup_iter_break() + * to cancel a hierarchy walk before the round-trip is complete. + * + * Reclaimers can specify a zone and a priority level in @reclaim to + * divide up the memcgs in the hierarchy among all concurrent + * reclaimers operating on the same zone and priority. + */ +struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, + struct mem_cgroup *prev, + struct mem_cgroup_reclaim_cookie *reclaim) +{ + struct reclaim_iter *uninitialized_var(iter); + struct cgroup_subsys_state *css = NULL; + struct mem_cgroup *memcg = NULL; + struct mem_cgroup *pos = NULL; + + if (mem_cgroup_disabled()) + return NULL; + + if (!root) + root = root_mem_cgroup; + + if (prev && !reclaim) + pos = prev; + + if (!root->use_hierarchy && root != root_mem_cgroup) { + if (prev) + goto out; + return root; + } + + rcu_read_lock(); + + if (reclaim) { + struct mem_cgroup_per_zone *mz; + + mz = mem_cgroup_zone_zoneinfo(root, reclaim->zone); + iter = &mz->iter[reclaim->priority]; + + if (prev && reclaim->generation != iter->generation) + goto out_unlock; + + do { + pos = READ_ONCE(iter->position); + /* + * A racing update may change the position and + * put the last reference, hence css_tryget(), + * or retry to see the updated position. + */ + } while (pos && !css_tryget(&pos->css)); + } + + if (pos) + css = &pos->css; + + for (;;) { + css = css_next_descendant_pre(css, &root->css); + if (!css) { + /* + * Reclaimers share the hierarchy walk, and a + * new one might jump in right at the end of + * the hierarchy - make sure they see at least + * one group and restart from the beginning. + */ + if (!prev) + continue; + break; + } + + /* + * Verify the css and acquire a reference. The root + * is provided by the caller, so we know it's alive + * and kicking, and don't take an extra reference. + */ + memcg = mem_cgroup_from_css(css); + + if (css == &root->css) + break; + + if (css_tryget(css)) { + /* + * Make sure the memcg is initialized: + * mem_cgroup_css_online() orders the the + * initialization against setting the flag. + */ + if (smp_load_acquire(&memcg->initialized)) + break; + + css_put(css); + } + + memcg = NULL; + } + + if (reclaim) { + if (cmpxchg(&iter->position, pos, memcg) == pos) { + if (memcg) + css_get(&memcg->css); + if (pos) + css_put(&pos->css); + } + + /* + * pairs with css_tryget when dereferencing iter->position + * above. + */ + if (pos) + css_put(&pos->css); + + if (!memcg) + iter->generation++; + else if (!prev) + reclaim->generation = iter->generation; + } + +out_unlock: + rcu_read_unlock(); +out: + if (prev && prev != root) + css_put(&prev->css); + + return memcg; +} + +/** + * mem_cgroup_iter_break - abort a hierarchy walk prematurely + * @root: hierarchy root + * @prev: last visited hierarchy member as returned by mem_cgroup_iter() + */ +void mem_cgroup_iter_break(struct mem_cgroup *root, + struct mem_cgroup *prev) +{ + if (!root) + root = root_mem_cgroup; + if (prev && prev != root) + css_put(&prev->css); +} + +/* + * Iteration constructs for visiting all cgroups (under a tree). If + * loops are exited prematurely (break), mem_cgroup_iter_break() must + * be used for reference counting. + */ +#define for_each_mem_cgroup_tree(iter, root) \ + for (iter = mem_cgroup_iter(root, NULL, NULL); \ + iter != NULL; \ + iter = mem_cgroup_iter(root, iter, NULL)) + +#define for_each_mem_cgroup(iter) \ + for (iter = mem_cgroup_iter(NULL, NULL, NULL); \ + iter != NULL; \ + iter = mem_cgroup_iter(NULL, iter, NULL)) + +void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx) +{ + struct mem_cgroup *memcg; + + rcu_read_lock(); + memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); + if (unlikely(!memcg)) + goto out; + + switch (idx) { + case PGFAULT: + this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]); + break; + case PGMAJFAULT: + this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]); + break; + default: + BUG(); + } +out: + rcu_read_unlock(); +} +EXPORT_SYMBOL(__mem_cgroup_count_vm_event); + +/** + * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg + * @zone: zone of the wanted lruvec + * @memcg: memcg of the wanted lruvec + * + * Returns the lru list vector holding pages for the given @zone and + * @mem. This can be the global zone lruvec, if the memory controller + * is disabled. + */ +struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone, + struct mem_cgroup *memcg) +{ + struct mem_cgroup_per_zone *mz; + struct lruvec *lruvec; + + if (mem_cgroup_disabled()) { + lruvec = &zone->lruvec; + goto out; + } + + mz = mem_cgroup_zone_zoneinfo(memcg, zone); + lruvec = &mz->lruvec; +out: + /* + * Since a node can be onlined after the mem_cgroup was created, + * we have to be prepared to initialize lruvec->zone here; + * and if offlined then reonlined, we need to reinitialize it. + */ + if (unlikely(lruvec->zone != zone)) + lruvec->zone = zone; + return lruvec; +} + +/** + * mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page + * @page: the page + * @zone: zone of the page + * + * This function is only safe when following the LRU page isolation + * and putback protocol: the LRU lock must be held, and the page must + * either be PageLRU() or the caller must have isolated/allocated it. + */ +struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone) +{ + struct mem_cgroup_per_zone *mz; + struct mem_cgroup *memcg; + struct lruvec *lruvec; + + if (mem_cgroup_disabled()) { + lruvec = &zone->lruvec; + goto out; + } + + memcg = page->mem_cgroup; + /* + * Swapcache readahead pages are added to the LRU - and + * possibly migrated - before they are charged. + */ + if (!memcg) + memcg = root_mem_cgroup; + + mz = mem_cgroup_page_zoneinfo(memcg, page); + lruvec = &mz->lruvec; +out: + /* + * Since a node can be onlined after the mem_cgroup was created, + * we have to be prepared to initialize lruvec->zone here; + * and if offlined then reonlined, we need to reinitialize it. + */ + if (unlikely(lruvec->zone != zone)) + lruvec->zone = zone; + return lruvec; +} + +/** + * mem_cgroup_update_lru_size - account for adding or removing an lru page + * @lruvec: mem_cgroup per zone lru vector + * @lru: index of lru list the page is sitting on + * @nr_pages: positive when adding or negative when removing + * + * This function must be called when a page is added to or removed from an + * lru list. + */ +void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru, + int nr_pages) +{ + struct mem_cgroup_per_zone *mz; + unsigned long *lru_size; + + if (mem_cgroup_disabled()) + return; + + mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec); + lru_size = mz->lru_size + lru; + *lru_size += nr_pages; + VM_BUG_ON((long)(*lru_size) < 0); +} + +bool mem_cgroup_is_descendant(struct mem_cgroup *memcg, struct mem_cgroup *root) +{ + if (root == memcg) + return true; + if (!root->use_hierarchy) + return false; + return cgroup_is_descendant(memcg->css.cgroup, root->css.cgroup); +} + +bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg) +{ + struct mem_cgroup *task_memcg; + struct task_struct *p; + bool ret; + + p = find_lock_task_mm(task); + if (p) { + task_memcg = get_mem_cgroup_from_mm(p->mm); + task_unlock(p); + } else { + /* + * All threads may have already detached their mm's, but the oom + * killer still needs to detect if they have already been oom + * killed to prevent needlessly killing additional tasks. + */ + rcu_read_lock(); + task_memcg = mem_cgroup_from_task(task); + css_get(&task_memcg->css); + rcu_read_unlock(); + } + ret = mem_cgroup_is_descendant(task_memcg, memcg); + css_put(&task_memcg->css); + return ret; +} + +int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec) +{ + unsigned long inactive_ratio; + unsigned long inactive; + unsigned long active; + unsigned long gb; + + inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON); + active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON); + + gb = (inactive + active) >> (30 - PAGE_SHIFT); + if (gb) + inactive_ratio = int_sqrt(10 * gb); + else + inactive_ratio = 1; + + return inactive * inactive_ratio < active; +} + +bool mem_cgroup_lruvec_online(struct lruvec *lruvec) +{ + struct mem_cgroup_per_zone *mz; + struct mem_cgroup *memcg; + + if (mem_cgroup_disabled()) + return true; + + mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec); + memcg = mz->memcg; + + return !!(memcg->css.flags & CSS_ONLINE); +} + +#define mem_cgroup_from_counter(counter, member) \ + container_of(counter, struct mem_cgroup, member) + +/** + * mem_cgroup_margin - calculate chargeable space of a memory cgroup + * @memcg: the memory cgroup + * + * Returns the maximum amount of memory @mem can be charged with, in + * pages. + */ +static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg) +{ + unsigned long margin = 0; + unsigned long count; + unsigned long limit; + + count = page_counter_read(&memcg->memory); + limit = READ_ONCE(memcg->memory.limit); + if (count < limit) + margin = limit - count; + + if (do_swap_account) { + count = page_counter_read(&memcg->memsw); + limit = READ_ONCE(memcg->memsw.limit); + if (count <= limit) + margin = min(margin, limit - count); + } + + return margin; +} + +int mem_cgroup_swappiness(struct mem_cgroup *memcg) +{ + /* root ? */ + if (mem_cgroup_disabled() || !memcg->css.parent) + return vm_swappiness; + + return memcg->swappiness; +} + +/* + * A routine for checking "mem" is under move_account() or not. + * + * Checking a cgroup is mc.from or mc.to or under hierarchy of + * moving cgroups. This is for waiting at high-memory pressure + * caused by "move". + */ +static bool mem_cgroup_under_move(struct mem_cgroup *memcg) +{ + struct mem_cgroup *from; + struct mem_cgroup *to; + bool ret = false; + /* + * Unlike task_move routines, we access mc.to, mc.from not under + * mutual exclusion by cgroup_mutex. Here, we take spinlock instead. + */ + spin_lock(&mc.lock); + from = mc.from; + to = mc.to; + if (!from) + goto unlock; + + ret = mem_cgroup_is_descendant(from, memcg) || + mem_cgroup_is_descendant(to, memcg); +unlock: + spin_unlock(&mc.lock); + return ret; +} + +static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg) +{ + if (mc.moving_task && current != mc.moving_task) { + if (mem_cgroup_under_move(memcg)) { + DEFINE_WAIT(wait); + prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE); + /* moving charge context might have finished. */ + if (mc.moving_task) + schedule(); + finish_wait(&mc.waitq, &wait); + return true; + } + } + return false; +} + +#define K(x) ((x) << (PAGE_SHIFT-10)) +/** + * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller. + * @memcg: The memory cgroup that went over limit + * @p: Task that is going to be killed + * + * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is + * enabled + */ +void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) +{ + /* oom_info_lock ensures that parallel ooms do not interleave */ + static DEFINE_MUTEX(oom_info_lock); + struct mem_cgroup *iter; + unsigned int i; + + mutex_lock(&oom_info_lock); + rcu_read_lock(); + + if (p) { + pr_info("Task in "); + pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id)); + pr_cont(" killed as a result of limit of "); + } else { + pr_info("Memory limit reached of cgroup "); + } + + pr_cont_cgroup_path(memcg->css.cgroup); + pr_cont("\n"); + + rcu_read_unlock(); + + pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n", + K((u64)page_counter_read(&memcg->memory)), + K((u64)memcg->memory.limit), memcg->memory.failcnt); + pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n", + K((u64)page_counter_read(&memcg->memsw)), + K((u64)memcg->memsw.limit), memcg->memsw.failcnt); + pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n", + K((u64)page_counter_read(&memcg->kmem)), + K((u64)memcg->kmem.limit), memcg->kmem.failcnt); + + for_each_mem_cgroup_tree(iter, memcg) { + pr_info("Memory cgroup stats for "); + pr_cont_cgroup_path(iter->css.cgroup); + pr_cont(":"); + + for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { + if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account) + continue; + pr_cont(" %s:%ldKB", mem_cgroup_stat_names[i], + K(mem_cgroup_read_stat(iter, i))); + } + + for (i = 0; i < NR_LRU_LISTS; i++) + pr_cont(" %s:%luKB", mem_cgroup_lru_names[i], + K(mem_cgroup_nr_lru_pages(iter, BIT(i)))); + + pr_cont("\n"); + } + mutex_unlock(&oom_info_lock); +} + +/* + * This function returns the number of memcg under hierarchy tree. Returns + * 1(self count) if no children. + */ +static int mem_cgroup_count_children(struct mem_cgroup *memcg) +{ + int num = 0; + struct mem_cgroup *iter; + + for_each_mem_cgroup_tree(iter, memcg) + num++; + return num; +} + +/* + * Return the memory (and swap, if configured) limit for a memcg. + */ +static unsigned long mem_cgroup_get_limit(struct mem_cgroup *memcg) +{ + unsigned long limit; + + limit = memcg->memory.limit; + if (mem_cgroup_swappiness(memcg)) { + unsigned long memsw_limit; + + memsw_limit = memcg->memsw.limit; + limit = min(limit + total_swap_pages, memsw_limit); + } + return limit; +} + +static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, + int order) +{ + struct mem_cgroup *iter; + unsigned long chosen_points = 0; + unsigned long totalpages; + unsigned int points = 0; + struct task_struct *chosen = NULL; + + /* + * If current has a pending SIGKILL or is exiting, then automatically + * select it. The goal is to allow it to allocate so that it may + * quickly exit and free its memory. + */ + if (fatal_signal_pending(current) || task_will_free_mem(current)) { + mark_tsk_oom_victim(current); + return; + } + + check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL, memcg); + totalpages = mem_cgroup_get_limit(memcg) ? : 1; + for_each_mem_cgroup_tree(iter, memcg) { + struct css_task_iter it; + struct task_struct *task; + + css_task_iter_start(&iter->css, &it); + while ((task = css_task_iter_next(&it))) { + switch (oom_scan_process_thread(task, totalpages, NULL, + false)) { + case OOM_SCAN_SELECT: + if (chosen) + put_task_struct(chosen); + chosen = task; + chosen_points = ULONG_MAX; + get_task_struct(chosen); + /* fall through */ + case OOM_SCAN_CONTINUE: + continue; + case OOM_SCAN_ABORT: + css_task_iter_end(&it); + mem_cgroup_iter_break(memcg, iter); + if (chosen) + put_task_struct(chosen); + return; + case OOM_SCAN_OK: + break; + }; + points = oom_badness(task, memcg, NULL, totalpages); + if (!points || points < chosen_points) + continue; + /* Prefer thread group leaders for display purposes */ + if (points == chosen_points && + thread_group_leader(chosen)) + continue; + + if (chosen) + put_task_struct(chosen); + chosen = task; + chosen_points = points; + get_task_struct(chosen); + } + css_task_iter_end(&it); + } + + if (!chosen) + return; + points = chosen_points * 1000 / totalpages; + oom_kill_process(chosen, gfp_mask, order, points, totalpages, memcg, + NULL, "Memory cgroup out of memory"); +} + +#if MAX_NUMNODES > 1 + +/** + * test_mem_cgroup_node_reclaimable + * @memcg: the target memcg + * @nid: the node ID to be checked. + * @noswap : specify true here if the user wants flle only information. + * + * This function returns whether the specified memcg contains any + * reclaimable pages on a node. Returns true if there are any reclaimable + * pages in the node. + */ +static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg, + int nid, bool noswap) +{ + if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE)) + return true; + if (noswap || !total_swap_pages) + return false; + if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON)) + return true; + return false; + +} + +/* + * Always updating the nodemask is not very good - even if we have an empty + * list or the wrong list here, we can start from some node and traverse all + * nodes based on the zonelist. So update the list loosely once per 10 secs. + * + */ +static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg) +{ + int nid; + /* + * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET + * pagein/pageout changes since the last update. + */ + if (!atomic_read(&memcg->numainfo_events)) + return; + if (atomic_inc_return(&memcg->numainfo_updating) > 1) + return; + + /* make a nodemask where this memcg uses memory from */ + memcg->scan_nodes = node_states[N_MEMORY]; + + for_each_node_mask(nid, node_states[N_MEMORY]) { + + if (!test_mem_cgroup_node_reclaimable(memcg, nid, false)) + node_clear(nid, memcg->scan_nodes); + } + + atomic_set(&memcg->numainfo_events, 0); + atomic_set(&memcg->numainfo_updating, 0); +} + +/* + * Selecting a node where we start reclaim from. Because what we need is just + * reducing usage counter, start from anywhere is O,K. Considering + * memory reclaim from current node, there are pros. and cons. + * + * Freeing memory from current node means freeing memory from a node which + * we'll use or we've used. So, it may make LRU bad. And if several threads + * hit limits, it will see a contention on a node. But freeing from remote + * node means more costs for memory reclaim because of memory latency. + * + * Now, we use round-robin. Better algorithm is welcomed. + */ +int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) +{ + int node; + + mem_cgroup_may_update_nodemask(memcg); + node = memcg->last_scanned_node; + + node = next_node(node, memcg->scan_nodes); + if (node == MAX_NUMNODES) + node = first_node(memcg->scan_nodes); + /* + * We call this when we hit limit, not when pages are added to LRU. + * No LRU may hold pages because all pages are UNEVICTABLE or + * memcg is too small and all pages are not on LRU. In that case, + * we use curret node. + */ + if (unlikely(node == MAX_NUMNODES)) + node = numa_node_id(); + + memcg->last_scanned_node = node; + return node; +} +#else +int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) +{ + return 0; +} +#endif + +static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg, + struct zone *zone, + gfp_t gfp_mask, + unsigned long *total_scanned) +{ + struct mem_cgroup *victim = NULL; + int total = 0; + int loop = 0; + unsigned long excess; + unsigned long nr_scanned; + struct mem_cgroup_reclaim_cookie reclaim = { + .zone = zone, + .priority = 0, + }; + + excess = soft_limit_excess(root_memcg); + + while (1) { + victim = mem_cgroup_iter(root_memcg, victim, &reclaim); + if (!victim) { + loop++; + if (loop >= 2) { + /* + * If we have not been able to reclaim + * anything, it might because there are + * no reclaimable pages under this hierarchy + */ + if (!total) + break; + /* + * We want to do more targeted reclaim. + * excess >> 2 is not to excessive so as to + * reclaim too much, nor too less that we keep + * coming back to reclaim from this cgroup + */ + if (total >= (excess >> 2) || + (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) + break; + } + continue; + } + total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false, + zone, &nr_scanned); + *total_scanned += nr_scanned; + if (!soft_limit_excess(root_memcg)) + break; + } + mem_cgroup_iter_break(root_memcg, victim); + return total; +} + +#ifdef CONFIG_LOCKDEP +static struct lockdep_map memcg_oom_lock_dep_map = { + .name = "memcg_oom_lock", +}; +#endif + +static DEFINE_SPINLOCK(memcg_oom_lock); + +/* + * Check OOM-Killer is already running under our hierarchy. + * If someone is running, return false. + */ +static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg) +{ + struct mem_cgroup *iter, *failed = NULL; + + spin_lock(&memcg_oom_lock); + + for_each_mem_cgroup_tree(iter, memcg) { + if (iter->oom_lock) { + /* + * this subtree of our hierarchy is already locked + * so we cannot give a lock. + */ + failed = iter; + mem_cgroup_iter_break(memcg, iter); + break; + } else + iter->oom_lock = true; + } + + if (failed) { + /* + * OK, we failed to lock the whole subtree so we have + * to clean up what we set up to the failing subtree + */ + for_each_mem_cgroup_tree(iter, memcg) { + if (iter == failed) { + mem_cgroup_iter_break(memcg, iter); + break; + } + iter->oom_lock = false; + } + } else + mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_); + + spin_unlock(&memcg_oom_lock); + + return !failed; +} + +static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg) +{ + struct mem_cgroup *iter; + + spin_lock(&memcg_oom_lock); + mutex_release(&memcg_oom_lock_dep_map, 1, _RET_IP_); + for_each_mem_cgroup_tree(iter, memcg) + iter->oom_lock = false; + spin_unlock(&memcg_oom_lock); +} + +static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg) +{ + struct mem_cgroup *iter; + + for_each_mem_cgroup_tree(iter, memcg) + atomic_inc(&iter->under_oom); +} + +static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg) +{ + struct mem_cgroup *iter; + + /* + * When a new child is created while the hierarchy is under oom, + * mem_cgroup_oom_lock() may not be called. We have to use + * atomic_add_unless() here. + */ + for_each_mem_cgroup_tree(iter, memcg) + atomic_add_unless(&iter->under_oom, -1, 0); +} + +static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq); + +struct oom_wait_info { + struct mem_cgroup *memcg; + wait_queue_t wait; +}; + +static int memcg_oom_wake_function(wait_queue_t *wait, + unsigned mode, int sync, void *arg) +{ + struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg; + struct mem_cgroup *oom_wait_memcg; + struct oom_wait_info *oom_wait_info; + + oom_wait_info = container_of(wait, struct oom_wait_info, wait); + oom_wait_memcg = oom_wait_info->memcg; + + if (!mem_cgroup_is_descendant(wake_memcg, oom_wait_memcg) && + !mem_cgroup_is_descendant(oom_wait_memcg, wake_memcg)) + return 0; + return autoremove_wake_function(wait, mode, sync, arg); +} + +static void memcg_wakeup_oom(struct mem_cgroup *memcg) +{ + atomic_inc(&memcg->oom_wakeups); + /* for filtering, pass "memcg" as argument. */ + __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg); +} + +static void memcg_oom_recover(struct mem_cgroup *memcg) +{ + if (memcg && atomic_read(&memcg->under_oom)) + memcg_wakeup_oom(memcg); +} + +static void mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order) +{ + if (!current->memcg_oom.may_oom) + return; + /* + * We are in the middle of the charge context here, so we + * don't want to block when potentially sitting on a callstack + * that holds all kinds of filesystem and mm locks. + * + * Also, the caller may handle a failed allocation gracefully + * (like optional page cache readahead) and so an OOM killer + * invocation might not even be necessary. + * + * That's why we don't do anything here except remember the + * OOM context and then deal with it at the end of the page + * fault when the stack is unwound, the locks are released, + * and when we know whether the fault was overall successful. + */ + css_get(&memcg->css); + current->memcg_oom.memcg = memcg; + current->memcg_oom.gfp_mask = mask; + current->memcg_oom.order = order; +} + +/** + * mem_cgroup_oom_synchronize - complete memcg OOM handling + * @handle: actually kill/wait or just clean up the OOM state + * + * This has to be called at the end of a page fault if the memcg OOM + * handler was enabled. + * + * Memcg supports userspace OOM handling where failed allocations must + * sleep on a waitqueue until the userspace task resolves the + * situation. Sleeping directly in the charge context with all kinds + * of locks held is not a good idea, instead we remember an OOM state + * in the task and mem_cgroup_oom_synchronize() has to be called at + * the end of the page fault to complete the OOM handling. + * + * Returns %true if an ongoing memcg OOM situation was detected and + * completed, %false otherwise. + */ +bool mem_cgroup_oom_synchronize(bool handle) +{ + struct mem_cgroup *memcg = current->memcg_oom.memcg; + struct oom_wait_info owait; + bool locked; + + /* OOM is global, do not handle */ + if (!memcg) + return false; + + if (!handle || oom_killer_disabled) + goto cleanup; + + owait.memcg = memcg; + owait.wait.flags = 0; + owait.wait.func = memcg_oom_wake_function; + owait.wait.private = current; + INIT_LIST_HEAD(&owait.wait.task_list); + + prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE); + mem_cgroup_mark_under_oom(memcg); + + locked = mem_cgroup_oom_trylock(memcg); + + if (locked) + mem_cgroup_oom_notify(memcg); + + if (locked && !memcg->oom_kill_disable) { + mem_cgroup_unmark_under_oom(memcg); + finish_wait(&memcg_oom_waitq, &owait.wait); + mem_cgroup_out_of_memory(memcg, current->memcg_oom.gfp_mask, + current->memcg_oom.order); + } else { + schedule(); + mem_cgroup_unmark_under_oom(memcg); + finish_wait(&memcg_oom_waitq, &owait.wait); + } + + if (locked) { + mem_cgroup_oom_unlock(memcg); + /* + * There is no guarantee that an OOM-lock contender + * sees the wakeups triggered by the OOM kill + * uncharges. Wake any sleepers explicitely. + */ + memcg_oom_recover(memcg); + } +cleanup: + current->memcg_oom.memcg = NULL; + css_put(&memcg->css); + return true; +} + +/** + * mem_cgroup_begin_page_stat - begin a page state statistics transaction + * @page: page that is going to change accounted state + * + * This function must mark the beginning of an accounted page state + * change to prevent double accounting when the page is concurrently + * being moved to another memcg: + * + * memcg = mem_cgroup_begin_page_stat(page); + * if (TestClearPageState(page)) + * mem_cgroup_update_page_stat(memcg, state, -1); + * mem_cgroup_end_page_stat(memcg); + */ +struct mem_cgroup *mem_cgroup_begin_page_stat(struct page *page) +{ + struct mem_cgroup *memcg; + unsigned long flags; + + /* + * The RCU lock is held throughout the transaction. The fast + * path can get away without acquiring the memcg->move_lock + * because page moving starts with an RCU grace period. + * + * The RCU lock also protects the memcg from being freed when + * the page state that is going to change is the only thing + * preventing the page from being uncharged. + * E.g. end-writeback clearing PageWriteback(), which allows + * migration to go ahead and uncharge the page before the + * account transaction might be complete. + */ + rcu_read_lock(); + + if (mem_cgroup_disabled()) + return NULL; +again: + memcg = page->mem_cgroup; + if (unlikely(!memcg)) + return NULL; + + if (atomic_read(&memcg->moving_account) <= 0) + return memcg; + + spin_lock_irqsave(&memcg->move_lock, flags); + if (memcg != page->mem_cgroup) { + spin_unlock_irqrestore(&memcg->move_lock, flags); + goto again; + } + + /* + * When charge migration first begins, we can have locked and + * unlocked page stat updates happening concurrently. Track + * the task who has the lock for mem_cgroup_end_page_stat(). + */ + memcg->move_lock_task = current; + memcg->move_lock_flags = flags; + + return memcg; +} + +/** + * mem_cgroup_end_page_stat - finish a page state statistics transaction + * @memcg: the memcg that was accounted against + */ +void mem_cgroup_end_page_stat(struct mem_cgroup *memcg) +{ + if (memcg && memcg->move_lock_task == current) { + unsigned long flags = memcg->move_lock_flags; + + memcg->move_lock_task = NULL; + memcg->move_lock_flags = 0; + + spin_unlock_irqrestore(&memcg->move_lock, flags); + } + + rcu_read_unlock(); +} + +/** + * mem_cgroup_update_page_stat - update page state statistics + * @memcg: memcg to account against + * @idx: page state item to account + * @val: number of pages (positive or negative) + * + * See mem_cgroup_begin_page_stat() for locking requirements. + */ +void mem_cgroup_update_page_stat(struct mem_cgroup *memcg, + enum mem_cgroup_stat_index idx, int val) +{ + VM_BUG_ON(!rcu_read_lock_held()); + + if (memcg) + this_cpu_add(memcg->stat->count[idx], val); +} + +/* + * size of first charge trial. "32" comes from vmscan.c's magic value. + * TODO: maybe necessary to use big numbers in big irons. + */ +#define CHARGE_BATCH 32U +struct memcg_stock_pcp { + struct mem_cgroup *cached; /* this never be root cgroup */ + unsigned int nr_pages; + struct work_struct work; + unsigned long flags; +#define FLUSHING_CACHED_CHARGE 0 +}; +static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock); +static DEFINE_MUTEX(percpu_charge_mutex); + +/** + * consume_stock: Try to consume stocked charge on this cpu. + * @memcg: memcg to consume from. + * @nr_pages: how many pages to charge. + * + * The charges will only happen if @memcg matches the current cpu's memcg + * stock, and at least @nr_pages are available in that stock. Failure to + * service an allocation will refill the stock. + * + * returns true if successful, false otherwise. + */ +static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages) +{ + struct memcg_stock_pcp *stock; + bool ret = false; + + if (nr_pages > CHARGE_BATCH) + return ret; + + stock = &get_cpu_var(memcg_stock); + if (memcg == stock->cached && stock->nr_pages >= nr_pages) { + stock->nr_pages -= nr_pages; + ret = true; + } + put_cpu_var(memcg_stock); + return ret; +} + +/* + * Returns stocks cached in percpu and reset cached information. + */ +static void drain_stock(struct memcg_stock_pcp *stock) +{ + struct mem_cgroup *old = stock->cached; + + if (stock->nr_pages) { + page_counter_uncharge(&old->memory, stock->nr_pages); + if (do_swap_account) + page_counter_uncharge(&old->memsw, stock->nr_pages); + css_put_many(&old->css, stock->nr_pages); + stock->nr_pages = 0; + } + stock->cached = NULL; +} + +/* + * This must be called under preempt disabled or must be called by + * a thread which is pinned to local cpu. + */ +static void drain_local_stock(struct work_struct *dummy) +{ + struct memcg_stock_pcp *stock = this_cpu_ptr(&memcg_stock); + drain_stock(stock); + clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); +} + +/* + * Cache charges(val) to local per_cpu area. + * This will be consumed by consume_stock() function, later. + */ +static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages) +{ + struct memcg_stock_pcp *stock; + int cpu = get_cpu_light(); + + stock = &per_cpu(memcg_stock, cpu); + + if (stock->cached != memcg) { /* reset if necessary */ + drain_stock(stock); + stock->cached = memcg; + } + stock->nr_pages += nr_pages; + put_cpu_light(); +} + +/* + * Drains all per-CPU charge caches for given root_memcg resp. subtree + * of the hierarchy under it. + */ +static void drain_all_stock(struct mem_cgroup *root_memcg) +{ + int cpu, curcpu; + + /* If someone's already draining, avoid adding running more workers. */ + if (!mutex_trylock(&percpu_charge_mutex)) + return; + /* Notify other cpus that system-wide "drain" is running */ + get_online_cpus(); + curcpu = get_cpu_light(); + for_each_online_cpu(cpu) { + struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); + struct mem_cgroup *memcg; + + memcg = stock->cached; + if (!memcg || !stock->nr_pages) + continue; + if (!mem_cgroup_is_descendant(memcg, root_memcg)) + continue; + if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) { + if (cpu == curcpu) + drain_local_stock(&stock->work); + else + schedule_work_on(cpu, &stock->work); + } + } + put_cpu_light(); + put_online_cpus(); + mutex_unlock(&percpu_charge_mutex); +} + +/* + * This function drains percpu counter value from DEAD cpu and + * move it to local cpu. Note that this function can be preempted. + */ +static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu) +{ + int i; + + spin_lock(&memcg->pcp_counter_lock); + for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { + long x = per_cpu(memcg->stat->count[i], cpu); + + per_cpu(memcg->stat->count[i], cpu) = 0; + memcg->nocpu_base.count[i] += x; + } + for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) { + unsigned long x = per_cpu(memcg->stat->events[i], cpu); + + per_cpu(memcg->stat->events[i], cpu) = 0; + memcg->nocpu_base.events[i] += x; + } + spin_unlock(&memcg->pcp_counter_lock); +} + +static int memcg_cpu_hotplug_callback(struct notifier_block *nb, + unsigned long action, + void *hcpu) +{ + int cpu = (unsigned long)hcpu; + struct memcg_stock_pcp *stock; + struct mem_cgroup *iter; + + if (action == CPU_ONLINE) + return NOTIFY_OK; + + if (action != CPU_DEAD && action != CPU_DEAD_FROZEN) + return NOTIFY_OK; + + for_each_mem_cgroup(iter) + mem_cgroup_drain_pcp_counter(iter, cpu); + + stock = &per_cpu(memcg_stock, cpu); + drain_stock(stock); + return NOTIFY_OK; +} + +static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, + unsigned int nr_pages) +{ + unsigned int batch = max(CHARGE_BATCH, nr_pages); + int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; + struct mem_cgroup *mem_over_limit; + struct page_counter *counter; + unsigned long nr_reclaimed; + bool may_swap = true; + bool drained = false; + int ret = 0; + + if (mem_cgroup_is_root(memcg)) + goto done; +retry: + if (consume_stock(memcg, nr_pages)) + goto done; + + if (!do_swap_account || + !page_counter_try_charge(&memcg->memsw, batch, &counter)) { + if (!page_counter_try_charge(&memcg->memory, batch, &counter)) + goto done_restock; + if (do_swap_account) + page_counter_uncharge(&memcg->memsw, batch); + mem_over_limit = mem_cgroup_from_counter(counter, memory); + } else { + mem_over_limit = mem_cgroup_from_counter(counter, memsw); + may_swap = false; + } + + if (batch > nr_pages) { + batch = nr_pages; + goto retry; + } + + /* + * Unlike in global OOM situations, memcg is not in a physical + * memory shortage. Allow dying and OOM-killed tasks to + * bypass the last charges so that they can exit quickly and + * free their memory. + */ + if (unlikely(test_thread_flag(TIF_MEMDIE) || + fatal_signal_pending(current) || + current->flags & PF_EXITING)) + goto bypass; + + if (unlikely(task_in_memcg_oom(current))) + goto nomem; + + if (!(gfp_mask & __GFP_WAIT)) + goto nomem; + + mem_cgroup_events(mem_over_limit, MEMCG_MAX, 1); + + nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages, + gfp_mask, may_swap); + + if (mem_cgroup_margin(mem_over_limit) >= nr_pages) + goto retry; + + if (!drained) { + drain_all_stock(mem_over_limit); + drained = true; + goto retry; + } + + if (gfp_mask & __GFP_NORETRY) + goto nomem; + /* + * Even though the limit is exceeded at this point, reclaim + * may have been able to free some pages. Retry the charge + * before killing the task. + * + * Only for regular pages, though: huge pages are rather + * unlikely to succeed so close to the limit, and we fall back + * to regular pages anyway in case of failure. + */ + if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER)) + goto retry; + /* + * At task move, charge accounts can be doubly counted. So, it's + * better to wait until the end of task_move if something is going on. + */ + if (mem_cgroup_wait_acct_move(mem_over_limit)) + goto retry; + + if (nr_retries--) + goto retry; + + if (gfp_mask & __GFP_NOFAIL) + goto bypass; + + if (fatal_signal_pending(current)) + goto bypass; + + mem_cgroup_events(mem_over_limit, MEMCG_OOM, 1); + + mem_cgroup_oom(mem_over_limit, gfp_mask, get_order(nr_pages)); +nomem: + if (!(gfp_mask & __GFP_NOFAIL)) + return -ENOMEM; +bypass: + return -EINTR; + +done_restock: + css_get_many(&memcg->css, batch); + if (batch > nr_pages) + refill_stock(memcg, batch - nr_pages); + if (!(gfp_mask & __GFP_WAIT)) + goto done; + /* + * If the hierarchy is above the normal consumption range, + * make the charging task trim their excess contribution. + */ + do { + if (page_counter_read(&memcg->memory) <= memcg->high) + continue; + mem_cgroup_events(memcg, MEMCG_HIGH, 1); + try_to_free_mem_cgroup_pages(memcg, nr_pages, gfp_mask, true); + } while ((memcg = parent_mem_cgroup(memcg))); +done: + return ret; +} + +static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages) +{ + if (mem_cgroup_is_root(memcg)) + return; + + page_counter_uncharge(&memcg->memory, nr_pages); + if (do_swap_account) + page_counter_uncharge(&memcg->memsw, nr_pages); + + css_put_many(&memcg->css, nr_pages); +} + +/* + * try_get_mem_cgroup_from_page - look up page's memcg association + * @page: the page + * + * Look up, get a css reference, and return the memcg that owns @page. + * + * The page must be locked to prevent racing with swap-in and page + * cache charges. If coming from an unlocked page table, the caller + * must ensure the page is on the LRU or this can race with charging. + */ +struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) +{ + struct mem_cgroup *memcg; + unsigned short id; + swp_entry_t ent; + + VM_BUG_ON_PAGE(!PageLocked(page), page); + + memcg = page->mem_cgroup; + if (memcg) { + if (!css_tryget_online(&memcg->css)) + memcg = NULL; + } else if (PageSwapCache(page)) { + ent.val = page_private(page); + id = lookup_swap_cgroup_id(ent); + rcu_read_lock(); + memcg = mem_cgroup_from_id(id); + if (memcg && !css_tryget_online(&memcg->css)) + memcg = NULL; + rcu_read_unlock(); + } + return memcg; +} + +static void lock_page_lru(struct page *page, int *isolated) +{ + struct zone *zone = page_zone(page); + + spin_lock_irq(&zone->lru_lock); + if (PageLRU(page)) { + struct lruvec *lruvec; + + lruvec = mem_cgroup_page_lruvec(page, zone); + ClearPageLRU(page); + del_page_from_lru_list(page, lruvec, page_lru(page)); + *isolated = 1; + } else + *isolated = 0; +} + +static void unlock_page_lru(struct page *page, int isolated) +{ + struct zone *zone = page_zone(page); + + if (isolated) { + struct lruvec *lruvec; + + lruvec = mem_cgroup_page_lruvec(page, zone); + VM_BUG_ON_PAGE(PageLRU(page), page); + SetPageLRU(page); + add_page_to_lru_list(page, lruvec, page_lru(page)); + } + spin_unlock_irq(&zone->lru_lock); +} + +static void commit_charge(struct page *page, struct mem_cgroup *memcg, + bool lrucare) +{ + int isolated; + + VM_BUG_ON_PAGE(page->mem_cgroup, page); + + /* + * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page + * may already be on some other mem_cgroup's LRU. Take care of it. + */ + if (lrucare) + lock_page_lru(page, &isolated); + + /* + * Nobody should be changing or seriously looking at + * page->mem_cgroup at this point: + * + * - the page is uncharged + * + * - the page is off-LRU + * + * - an anonymous fault has exclusive page access, except for + * a locked page table + * + * - a page cache insertion, a swapin fault, or a migration + * have the page locked + */ + page->mem_cgroup = memcg; + + if (lrucare) + unlock_page_lru(page, isolated); +} + +#ifdef CONFIG_MEMCG_KMEM +int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, + unsigned long nr_pages) +{ + struct page_counter *counter; + int ret = 0; + + ret = page_counter_try_charge(&memcg->kmem, nr_pages, &counter); + if (ret < 0) + return ret; + + ret = try_charge(memcg, gfp, nr_pages); + if (ret == -EINTR) { + /* + * try_charge() chose to bypass to root due to OOM kill or + * fatal signal. Since our only options are to either fail + * the allocation or charge it to this cgroup, do it as a + * temporary condition. But we can't fail. From a kmem/slab + * perspective, the cache has already been selected, by + * mem_cgroup_kmem_get_cache(), so it is too late to change + * our minds. + * + * This condition will only trigger if the task entered + * memcg_charge_kmem in a sane state, but was OOM-killed + * during try_charge() above. Tasks that were already dying + * when the allocation triggers should have been already + * directed to the root cgroup in memcontrol.h + */ + page_counter_charge(&memcg->memory, nr_pages); + if (do_swap_account) + page_counter_charge(&memcg->memsw, nr_pages); + css_get_many(&memcg->css, nr_pages); + ret = 0; + } else if (ret) + page_counter_uncharge(&memcg->kmem, nr_pages); + + return ret; +} + +void memcg_uncharge_kmem(struct mem_cgroup *memcg, unsigned long nr_pages) +{ + page_counter_uncharge(&memcg->memory, nr_pages); + if (do_swap_account) + page_counter_uncharge(&memcg->memsw, nr_pages); + + page_counter_uncharge(&memcg->kmem, nr_pages); + + css_put_many(&memcg->css, nr_pages); +} + +/* + * helper for acessing a memcg's index. It will be used as an index in the + * child cache array in kmem_cache, and also to derive its name. This function + * will return -1 when this is not a kmem-limited memcg. + */ +int memcg_cache_id(struct mem_cgroup *memcg) +{ + return memcg ? memcg->kmemcg_id : -1; +} + +static int memcg_alloc_cache_id(void) +{ + int id, size; + int err; + + id = ida_simple_get(&memcg_cache_ida, + 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL); + if (id < 0) + return id; + + if (id < memcg_nr_cache_ids) + return id; + + /* + * There's no space for the new id in memcg_caches arrays, + * so we have to grow them. + */ + down_write(&memcg_cache_ids_sem); + + size = 2 * (id + 1); + if (size < MEMCG_CACHES_MIN_SIZE) + size = MEMCG_CACHES_MIN_SIZE; + else if (size > MEMCG_CACHES_MAX_SIZE) + size = MEMCG_CACHES_MAX_SIZE; + + err = memcg_update_all_caches(size); + if (!err) + err = memcg_update_all_list_lrus(size); + if (!err) + memcg_nr_cache_ids = size; + + up_write(&memcg_cache_ids_sem); + + if (err) { + ida_simple_remove(&memcg_cache_ida, id); + return err; + } + return id; +} + +static void memcg_free_cache_id(int id) +{ + ida_simple_remove(&memcg_cache_ida, id); +} + +struct memcg_kmem_cache_create_work { + struct mem_cgroup *memcg; + struct kmem_cache *cachep; + struct work_struct work; +}; + +static void memcg_kmem_cache_create_func(struct work_struct *w) +{ + struct memcg_kmem_cache_create_work *cw = + container_of(w, struct memcg_kmem_cache_create_work, work); + struct mem_cgroup *memcg = cw->memcg; + struct kmem_cache *cachep = cw->cachep; + + memcg_create_kmem_cache(memcg, cachep); + + css_put(&memcg->css); + kfree(cw); +} + +/* + * Enqueue the creation of a per-memcg kmem_cache. + */ +static void __memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg, + struct kmem_cache *cachep) +{ + struct memcg_kmem_cache_create_work *cw; + + cw = kmalloc(sizeof(*cw), GFP_NOWAIT); + if (!cw) + return; + + css_get(&memcg->css); + + cw->memcg = memcg; + cw->cachep = cachep; + INIT_WORK(&cw->work, memcg_kmem_cache_create_func); + + schedule_work(&cw->work); +} + +static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg, + struct kmem_cache *cachep) +{ + /* + * We need to stop accounting when we kmalloc, because if the + * corresponding kmalloc cache is not yet created, the first allocation + * in __memcg_schedule_kmem_cache_create will recurse. + * + * However, it is better to enclose the whole function. Depending on + * the debugging options enabled, INIT_WORK(), for instance, can + * trigger an allocation. This too, will make us recurse. Because at + * this point we can't allow ourselves back into memcg_kmem_get_cache, + * the safest choice is to do it like this, wrapping the whole function. + */ + current->memcg_kmem_skip_account = 1; + __memcg_schedule_kmem_cache_create(memcg, cachep); + current->memcg_kmem_skip_account = 0; +} + +/* + * Return the kmem_cache we're supposed to use for a slab allocation. + * We try to use the current memcg's version of the cache. + * + * If the cache does not exist yet, if we are the first user of it, + * we either create it immediately, if possible, or create it asynchronously + * in a workqueue. + * In the latter case, we will let the current allocation go through with + * the original cache. + * + * Can't be called in interrupt context or from kernel threads. + * This function needs to be called with rcu_read_lock() held. + */ +struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep) +{ + struct mem_cgroup *memcg; + struct kmem_cache *memcg_cachep; + int kmemcg_id; + + VM_BUG_ON(!is_root_cache(cachep)); + + if (current->memcg_kmem_skip_account) + return cachep; + + memcg = get_mem_cgroup_from_mm(current->mm); + kmemcg_id = READ_ONCE(memcg->kmemcg_id); + if (kmemcg_id < 0) + goto out; + + memcg_cachep = cache_from_memcg_idx(cachep, kmemcg_id); + if (likely(memcg_cachep)) + return memcg_cachep; + + /* + * If we are in a safe context (can wait, and not in interrupt + * context), we could be be predictable and return right away. + * This would guarantee that the allocation being performed + * already belongs in the new cache. + * + * However, there are some clashes that can arrive from locking. + * For instance, because we acquire the slab_mutex while doing + * memcg_create_kmem_cache, this means no further allocation + * could happen with the slab_mutex held. So it's better to + * defer everything. + */ + memcg_schedule_kmem_cache_create(memcg, cachep); +out: + css_put(&memcg->css); + return cachep; +} + +void __memcg_kmem_put_cache(struct kmem_cache *cachep) +{ + if (!is_root_cache(cachep)) + css_put(&cachep->memcg_params.memcg->css); +} + +/* + * We need to verify if the allocation against current->mm->owner's memcg is + * possible for the given order. But the page is not allocated yet, so we'll + * need a further commit step to do the final arrangements. + * + * It is possible for the task to switch cgroups in this mean time, so at + * commit time, we can't rely on task conversion any longer. We'll then use + * the handle argument to return to the caller which cgroup we should commit + * against. We could also return the memcg directly and avoid the pointer + * passing, but a boolean return value gives better semantics considering + * the compiled-out case as well. + * + * Returning true means the allocation is possible. + */ +bool +__memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order) +{ + struct mem_cgroup *memcg; + int ret; + + *_memcg = NULL; + + memcg = get_mem_cgroup_from_mm(current->mm); + + if (!memcg_kmem_is_active(memcg)) { + css_put(&memcg->css); + return true; + } + + ret = memcg_charge_kmem(memcg, gfp, 1 << order); + if (!ret) + *_memcg = memcg; + + css_put(&memcg->css); + return (ret == 0); +} + +void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, + int order) +{ + VM_BUG_ON(mem_cgroup_is_root(memcg)); + + /* The page allocation failed. Revert */ + if (!page) { + memcg_uncharge_kmem(memcg, 1 << order); + return; + } + page->mem_cgroup = memcg; +} + +void __memcg_kmem_uncharge_pages(struct page *page, int order) +{ + struct mem_cgroup *memcg = page->mem_cgroup; + + if (!memcg) + return; + + VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page); + + memcg_uncharge_kmem(memcg, 1 << order); + page->mem_cgroup = NULL; +} + +struct mem_cgroup *__mem_cgroup_from_kmem(void *ptr) +{ + struct mem_cgroup *memcg = NULL; + struct kmem_cache *cachep; + struct page *page; + + page = virt_to_head_page(ptr); + if (PageSlab(page)) { + cachep = page->slab_cache; + if (!is_root_cache(cachep)) + memcg = cachep->memcg_params.memcg; + } else + /* page allocated by alloc_kmem_pages */ + memcg = page->mem_cgroup; + + return memcg; +} +#endif /* CONFIG_MEMCG_KMEM */ + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + +/* + * Because tail pages are not marked as "used", set it. We're under + * zone->lru_lock, 'splitting on pmd' and compound_lock. + * charge/uncharge will be never happen and move_account() is done under + * compound_lock(), so we don't have to take care of races. + */ +void mem_cgroup_split_huge_fixup(struct page *head) +{ + int i; + + if (mem_cgroup_disabled()) + return; + + for (i = 1; i < HPAGE_PMD_NR; i++) + head[i].mem_cgroup = head->mem_cgroup; + + __this_cpu_sub(head->mem_cgroup->stat->count[MEM_CGROUP_STAT_RSS_HUGE], + HPAGE_PMD_NR); +} +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ + +#ifdef CONFIG_MEMCG_SWAP +static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg, + bool charge) +{ + int val = (charge) ? 1 : -1; + this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val); +} + +/** + * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record. + * @entry: swap entry to be moved + * @from: mem_cgroup which the entry is moved from + * @to: mem_cgroup which the entry is moved to + * + * It succeeds only when the swap_cgroup's record for this entry is the same + * as the mem_cgroup's id of @from. + * + * Returns 0 on success, -EINVAL on failure. + * + * The caller must have charged to @to, IOW, called page_counter_charge() about + * both res and memsw, and called css_get(). + */ +static int mem_cgroup_move_swap_account(swp_entry_t entry, + struct mem_cgroup *from, struct mem_cgroup *to) +{ + unsigned short old_id, new_id; + + old_id = mem_cgroup_id(from); + new_id = mem_cgroup_id(to); + + if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { + mem_cgroup_swap_statistics(from, false); + mem_cgroup_swap_statistics(to, true); + return 0; + } + return -EINVAL; +} +#else +static inline int mem_cgroup_move_swap_account(swp_entry_t entry, + struct mem_cgroup *from, struct mem_cgroup *to) +{ + return -EINVAL; +} +#endif + +static DEFINE_MUTEX(memcg_limit_mutex); + +static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, + unsigned long limit) +{ + unsigned long curusage; + unsigned long oldusage; + bool enlarge = false; + int retry_count; + int ret; + + /* + * For keeping hierarchical_reclaim simple, how long we should retry + * is depends on callers. We set our retry-count to be function + * of # of children which we should visit in this loop. + */ + retry_count = MEM_CGROUP_RECLAIM_RETRIES * + mem_cgroup_count_children(memcg); + + oldusage = page_counter_read(&memcg->memory); + + do { + if (signal_pending(current)) { + ret = -EINTR; + break; + } + + mutex_lock(&memcg_limit_mutex); + if (limit > memcg->memsw.limit) { + mutex_unlock(&memcg_limit_mutex); + ret = -EINVAL; + break; + } + if (limit > memcg->memory.limit) + enlarge = true; + ret = page_counter_limit(&memcg->memory, limit); + mutex_unlock(&memcg_limit_mutex); + + if (!ret) + break; + + try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, true); + + curusage = page_counter_read(&memcg->memory); + /* Usage is reduced ? */ + if (curusage >= oldusage) + retry_count--; + else + oldusage = curusage; + } while (retry_count); + + if (!ret && enlarge) + memcg_oom_recover(memcg); + + return ret; +} + +static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, + unsigned long limit) +{ + unsigned long curusage; + unsigned long oldusage; + bool enlarge = false; + int retry_count; + int ret; + + /* see mem_cgroup_resize_res_limit */ + retry_count = MEM_CGROUP_RECLAIM_RETRIES * + mem_cgroup_count_children(memcg); + + oldusage = page_counter_read(&memcg->memsw); + + do { + if (signal_pending(current)) { + ret = -EINTR; + break; + } + + mutex_lock(&memcg_limit_mutex); + if (limit < memcg->memory.limit) { + mutex_unlock(&memcg_limit_mutex); + ret = -EINVAL; + break; + } + if (limit > memcg->memsw.limit) + enlarge = true; + ret = page_counter_limit(&memcg->memsw, limit); + mutex_unlock(&memcg_limit_mutex); + + if (!ret) + break; + + try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, false); + + curusage = page_counter_read(&memcg->memsw); + /* Usage is reduced ? */ + if (curusage >= oldusage) + retry_count--; + else + oldusage = curusage; + } while (retry_count); + + if (!ret && enlarge) + memcg_oom_recover(memcg); + + return ret; +} + +unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, + gfp_t gfp_mask, + unsigned long *total_scanned) +{ + unsigned long nr_reclaimed = 0; + struct mem_cgroup_per_zone *mz, *next_mz = NULL; + unsigned long reclaimed; + int loop = 0; + struct mem_cgroup_tree_per_zone *mctz; + unsigned long excess; + unsigned long nr_scanned; + + if (order > 0) + return 0; + + mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone)); + /* + * This loop can run a while, specially if mem_cgroup's continuously + * keep exceeding their soft limit and putting the system under + * pressure + */ + do { + if (next_mz) + mz = next_mz; + else + mz = mem_cgroup_largest_soft_limit_node(mctz); + if (!mz) + break; + + nr_scanned = 0; + reclaimed = mem_cgroup_soft_reclaim(mz->memcg, zone, + gfp_mask, &nr_scanned); + nr_reclaimed += reclaimed; + *total_scanned += nr_scanned; + spin_lock_irq(&mctz->lock); + __mem_cgroup_remove_exceeded(mz, mctz); + + /* + * If we failed to reclaim anything from this memory cgroup + * it is time to move on to the next cgroup + */ + next_mz = NULL; + if (!reclaimed) + next_mz = __mem_cgroup_largest_soft_limit_node(mctz); + + excess = soft_limit_excess(mz->memcg); + /* + * One school of thought says that we should not add + * back the node to the tree if reclaim returns 0. + * But our reclaim could return 0, simply because due + * to priority we are exposing a smaller subset of + * memory to reclaim from. Consider this as a longer + * term TODO. + */ + /* If excess == 0, no tree ops */ + __mem_cgroup_insert_exceeded(mz, mctz, excess); + spin_unlock_irq(&mctz->lock); + css_put(&mz->memcg->css); + loop++; + /* + * Could not reclaim anything and there are no more + * mem cgroups to try or we seem to be looping without + * reclaiming anything. + */ + if (!nr_reclaimed && + (next_mz == NULL || + loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS)) + break; + } while (!nr_reclaimed); + if (next_mz) + css_put(&next_mz->memcg->css); + return nr_reclaimed; +} + +/* + * Test whether @memcg has children, dead or alive. Note that this + * function doesn't care whether @memcg has use_hierarchy enabled and + * returns %true if there are child csses according to the cgroup + * hierarchy. Testing use_hierarchy is the caller's responsiblity. + */ +static inline bool memcg_has_children(struct mem_cgroup *memcg) +{ + bool ret; + + /* + * The lock does not prevent addition or deletion of children, but + * it prevents a new child from being initialized based on this + * parent in css_online(), so it's enough to decide whether + * hierarchically inherited attributes can still be changed or not. + */ + lockdep_assert_held(&memcg_create_mutex); + + rcu_read_lock(); + ret = css_next_child(NULL, &memcg->css); + rcu_read_unlock(); + return ret; +} + +/* + * Reclaims as many pages from the given memcg as possible and moves + * the rest to the parent. + * + * Caller is responsible for holding css reference for memcg. + */ +static int mem_cgroup_force_empty(struct mem_cgroup *memcg) +{ + int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; + + /* we call try-to-free pages for make this cgroup empty */ + lru_add_drain_all(); + /* try to free all pages in this cgroup */ + while (nr_retries && page_counter_read(&memcg->memory)) { + int progress; + + if (signal_pending(current)) + return -EINTR; + + progress = try_to_free_mem_cgroup_pages(memcg, 1, + GFP_KERNEL, true); + if (!progress) { + nr_retries--; + /* maybe some writeback is necessary */ + congestion_wait(BLK_RW_ASYNC, HZ/10); + } + + } + + return 0; +} + +static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, + loff_t off) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + + if (mem_cgroup_is_root(memcg)) + return -EINVAL; + return mem_cgroup_force_empty(memcg) ?: nbytes; +} + +static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css, + struct cftype *cft) +{ + return mem_cgroup_from_css(css)->use_hierarchy; +} + +static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css, + struct cftype *cft, u64 val) +{ + int retval = 0; + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + struct mem_cgroup *parent_memcg = mem_cgroup_from_css(memcg->css.parent); + + mutex_lock(&memcg_create_mutex); + + if (memcg->use_hierarchy == val) + goto out; + + /* + * If parent's use_hierarchy is set, we can't make any modifications + * in the child subtrees. If it is unset, then the change can + * occur, provided the current cgroup has no children. + * + * For the root cgroup, parent_mem is NULL, we allow value to be + * set if there are no children. + */ + if ((!parent_memcg || !parent_memcg->use_hierarchy) && + (val == 1 || val == 0)) { + if (!memcg_has_children(memcg)) + memcg->use_hierarchy = val; + else + retval = -EBUSY; + } else + retval = -EINVAL; + +out: + mutex_unlock(&memcg_create_mutex); + + return retval; +} + +static unsigned long tree_stat(struct mem_cgroup *memcg, + enum mem_cgroup_stat_index idx) +{ + struct mem_cgroup *iter; + long val = 0; + + /* Per-cpu values can be negative, use a signed accumulator */ + for_each_mem_cgroup_tree(iter, memcg) + val += mem_cgroup_read_stat(iter, idx); + + if (val < 0) /* race ? */ + val = 0; + return val; +} + +static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) +{ + u64 val; + + if (mem_cgroup_is_root(memcg)) { + val = tree_stat(memcg, MEM_CGROUP_STAT_CACHE); + val += tree_stat(memcg, MEM_CGROUP_STAT_RSS); + if (swap) + val += tree_stat(memcg, MEM_CGROUP_STAT_SWAP); + } else { + if (!swap) + val = page_counter_read(&memcg->memory); + else + val = page_counter_read(&memcg->memsw); + } + return val << PAGE_SHIFT; +} + +enum { + RES_USAGE, + RES_LIMIT, + RES_MAX_USAGE, + RES_FAILCNT, + RES_SOFT_LIMIT, +}; + +static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css, + struct cftype *cft) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + struct page_counter *counter; + + switch (MEMFILE_TYPE(cft->private)) { + case _MEM: + counter = &memcg->memory; + break; + case _MEMSWAP: + counter = &memcg->memsw; + break; + case _KMEM: + counter = &memcg->kmem; + break; + default: + BUG(); + } + + switch (MEMFILE_ATTR(cft->private)) { + case RES_USAGE: + if (counter == &memcg->memory) + return mem_cgroup_usage(memcg, false); + if (counter == &memcg->memsw) + return mem_cgroup_usage(memcg, true); + return (u64)page_counter_read(counter) * PAGE_SIZE; + case RES_LIMIT: + return (u64)counter->limit * PAGE_SIZE; + case RES_MAX_USAGE: + return (u64)counter->watermark * PAGE_SIZE; + case RES_FAILCNT: + return counter->failcnt; + case RES_SOFT_LIMIT: + return (u64)memcg->soft_limit * PAGE_SIZE; + default: + BUG(); + } +} + +#ifdef CONFIG_MEMCG_KMEM +static int memcg_activate_kmem(struct mem_cgroup *memcg, + unsigned long nr_pages) +{ + int err = 0; + int memcg_id; + + BUG_ON(memcg->kmemcg_id >= 0); + BUG_ON(memcg->kmem_acct_activated); + BUG_ON(memcg->kmem_acct_active); + + /* + * For simplicity, we won't allow this to be disabled. It also can't + * be changed if the cgroup has children already, or if tasks had + * already joined. + * + * If tasks join before we set the limit, a person looking at + * kmem.usage_in_bytes will have no way to determine when it took + * place, which makes the value quite meaningless. + * + * After it first became limited, changes in the value of the limit are + * of course permitted. + */ + mutex_lock(&memcg_create_mutex); + if (cgroup_has_tasks(memcg->css.cgroup) || + (memcg->use_hierarchy && memcg_has_children(memcg))) + err = -EBUSY; + mutex_unlock(&memcg_create_mutex); + if (err) + goto out; + + memcg_id = memcg_alloc_cache_id(); + if (memcg_id < 0) { + err = memcg_id; + goto out; + } + + /* + * We couldn't have accounted to this cgroup, because it hasn't got + * activated yet, so this should succeed. + */ + err = page_counter_limit(&memcg->kmem, nr_pages); + VM_BUG_ON(err); + + static_key_slow_inc(&memcg_kmem_enabled_key); + /* + * A memory cgroup is considered kmem-active as soon as it gets + * kmemcg_id. Setting the id after enabling static branching will + * guarantee no one starts accounting before all call sites are + * patched. + */ + memcg->kmemcg_id = memcg_id; + memcg->kmem_acct_activated = true; + memcg->kmem_acct_active = true; +out: + return err; +} + +static int memcg_update_kmem_limit(struct mem_cgroup *memcg, + unsigned long limit) +{ + int ret; + + mutex_lock(&memcg_limit_mutex); + if (!memcg_kmem_is_active(memcg)) + ret = memcg_activate_kmem(memcg, limit); + else + ret = page_counter_limit(&memcg->kmem, limit); + mutex_unlock(&memcg_limit_mutex); + return ret; +} + +static int memcg_propagate_kmem(struct mem_cgroup *memcg) +{ + int ret = 0; + struct mem_cgroup *parent = parent_mem_cgroup(memcg); + + if (!parent) + return 0; + + mutex_lock(&memcg_limit_mutex); + /* + * If the parent cgroup is not kmem-active now, it cannot be activated + * after this point, because it has at least one child already. + */ + if (memcg_kmem_is_active(parent)) + ret = memcg_activate_kmem(memcg, PAGE_COUNTER_MAX); + mutex_unlock(&memcg_limit_mutex); + return ret; +} +#else +static int memcg_update_kmem_limit(struct mem_cgroup *memcg, + unsigned long limit) +{ + return -EINVAL; +} +#endif /* CONFIG_MEMCG_KMEM */ + +/* + * The user of this function is... + * RES_LIMIT. + */ +static ssize_t mem_cgroup_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + unsigned long nr_pages; + int ret; + + buf = strstrip(buf); + ret = page_counter_memparse(buf, "-1", &nr_pages); + if (ret) + return ret; + + switch (MEMFILE_ATTR(of_cft(of)->private)) { + case RES_LIMIT: + if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */ + ret = -EINVAL; + break; + } + switch (MEMFILE_TYPE(of_cft(of)->private)) { + case _MEM: + ret = mem_cgroup_resize_limit(memcg, nr_pages); + break; + case _MEMSWAP: + ret = mem_cgroup_resize_memsw_limit(memcg, nr_pages); + break; + case _KMEM: + ret = memcg_update_kmem_limit(memcg, nr_pages); + break; + } + break; + case RES_SOFT_LIMIT: + memcg->soft_limit = nr_pages; + ret = 0; + break; + } + return ret ?: nbytes; +} + +static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf, + size_t nbytes, loff_t off) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + struct page_counter *counter; + + switch (MEMFILE_TYPE(of_cft(of)->private)) { + case _MEM: + counter = &memcg->memory; + break; + case _MEMSWAP: + counter = &memcg->memsw; + break; + case _KMEM: + counter = &memcg->kmem; + break; + default: + BUG(); + } + + switch (MEMFILE_ATTR(of_cft(of)->private)) { + case RES_MAX_USAGE: + page_counter_reset_watermark(counter); + break; + case RES_FAILCNT: + counter->failcnt = 0; + break; + default: + BUG(); + } + + return nbytes; +} + +static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css, + struct cftype *cft) +{ + return mem_cgroup_from_css(css)->move_charge_at_immigrate; +} + +#ifdef CONFIG_MMU +static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, + struct cftype *cft, u64 val) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + + if (val & ~MOVE_MASK) + return -EINVAL; + + /* + * No kind of locking is needed in here, because ->can_attach() will + * check this value once in the beginning of the process, and then carry + * on with stale data. This means that changes to this value will only + * affect task migrations starting after the change. + */ + memcg->move_charge_at_immigrate = val; + return 0; +} +#else +static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, + struct cftype *cft, u64 val) +{ + return -ENOSYS; +} +#endif + +#ifdef CONFIG_NUMA +static int memcg_numa_stat_show(struct seq_file *m, void *v) +{ + struct numa_stat { + const char *name; + unsigned int lru_mask; + }; + + static const struct numa_stat stats[] = { + { "total", LRU_ALL }, + { "file", LRU_ALL_FILE }, + { "anon", LRU_ALL_ANON }, + { "unevictable", BIT(LRU_UNEVICTABLE) }, + }; + const struct numa_stat *stat; + int nid; + unsigned long nr; + struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); + + for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { + nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask); + seq_printf(m, "%s=%lu", stat->name, nr); + for_each_node_state(nid, N_MEMORY) { + nr = mem_cgroup_node_nr_lru_pages(memcg, nid, + stat->lru_mask); + seq_printf(m, " N%d=%lu", nid, nr); + } + seq_putc(m, '\n'); + } + + for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { + struct mem_cgroup *iter; + + nr = 0; + for_each_mem_cgroup_tree(iter, memcg) + nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask); + seq_printf(m, "hierarchical_%s=%lu", stat->name, nr); + for_each_node_state(nid, N_MEMORY) { + nr = 0; + for_each_mem_cgroup_tree(iter, memcg) + nr += mem_cgroup_node_nr_lru_pages( + iter, nid, stat->lru_mask); + seq_printf(m, " N%d=%lu", nid, nr); + } + seq_putc(m, '\n'); + } + + return 0; +} +#endif /* CONFIG_NUMA */ + +static int memcg_stat_show(struct seq_file *m, void *v) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); + unsigned long memory, memsw; + struct mem_cgroup *mi; + unsigned int i; + + BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_stat_names) != + MEM_CGROUP_STAT_NSTATS); + BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_events_names) != + MEM_CGROUP_EVENTS_NSTATS); + BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS); + + for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { + if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account) + continue; + seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i], + mem_cgroup_read_stat(memcg, i) * PAGE_SIZE); + } + + for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) + seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i], + mem_cgroup_read_events(memcg, i)); + + for (i = 0; i < NR_LRU_LISTS; i++) + seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i], + mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE); + + /* Hierarchical information */ + memory = memsw = PAGE_COUNTER_MAX; + for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) { + memory = min(memory, mi->memory.limit); + memsw = min(memsw, mi->memsw.limit); + } + seq_printf(m, "hierarchical_memory_limit %llu\n", + (u64)memory * PAGE_SIZE); + if (do_swap_account) + seq_printf(m, "hierarchical_memsw_limit %llu\n", + (u64)memsw * PAGE_SIZE); + + for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { + long long val = 0; + + if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account) + continue; + for_each_mem_cgroup_tree(mi, memcg) + val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE; + seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val); + } + + for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) { + unsigned long long val = 0; + + for_each_mem_cgroup_tree(mi, memcg) + val += mem_cgroup_read_events(mi, i); + seq_printf(m, "total_%s %llu\n", + mem_cgroup_events_names[i], val); + } + + for (i = 0; i < NR_LRU_LISTS; i++) { + unsigned long long val = 0; + + for_each_mem_cgroup_tree(mi, memcg) + val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE; + seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val); + } + +#ifdef CONFIG_DEBUG_VM + { + int nid, zid; + struct mem_cgroup_per_zone *mz; + struct zone_reclaim_stat *rstat; + unsigned long recent_rotated[2] = {0, 0}; + unsigned long recent_scanned[2] = {0, 0}; + + for_each_online_node(nid) + for (zid = 0; zid < MAX_NR_ZONES; zid++) { + mz = &memcg->nodeinfo[nid]->zoneinfo[zid]; + rstat = &mz->lruvec.reclaim_stat; + + recent_rotated[0] += rstat->recent_rotated[0]; + recent_rotated[1] += rstat->recent_rotated[1]; + recent_scanned[0] += rstat->recent_scanned[0]; + recent_scanned[1] += rstat->recent_scanned[1]; + } + seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]); + seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]); + seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]); + seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]); + } +#endif + + return 0; +} + +static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css, + struct cftype *cft) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + + return mem_cgroup_swappiness(memcg); +} + +static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css, + struct cftype *cft, u64 val) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + + if (val > 100) + return -EINVAL; + + if (css->parent) + memcg->swappiness = val; + else + vm_swappiness = val; + + return 0; +} + +static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap) +{ + struct mem_cgroup_threshold_ary *t; + unsigned long usage; + int i; + + rcu_read_lock(); + if (!swap) + t = rcu_dereference(memcg->thresholds.primary); + else + t = rcu_dereference(memcg->memsw_thresholds.primary); + + if (!t) + goto unlock; + + usage = mem_cgroup_usage(memcg, swap); + + /* + * current_threshold points to threshold just below or equal to usage. + * If it's not true, a threshold was crossed after last + * call of __mem_cgroup_threshold(). + */ + i = t->current_threshold; + + /* + * Iterate backward over array of thresholds starting from + * current_threshold and check if a threshold is crossed. + * If none of thresholds below usage is crossed, we read + * only one element of the array here. + */ + for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--) + eventfd_signal(t->entries[i].eventfd, 1); + + /* i = current_threshold + 1 */ + i++; + + /* + * Iterate forward over array of thresholds starting from + * current_threshold+1 and check if a threshold is crossed. + * If none of thresholds above usage is crossed, we read + * only one element of the array here. + */ + for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++) + eventfd_signal(t->entries[i].eventfd, 1); + + /* Update current_threshold */ + t->current_threshold = i - 1; +unlock: + rcu_read_unlock(); +} + +static void mem_cgroup_threshold(struct mem_cgroup *memcg) +{ + while (memcg) { + __mem_cgroup_threshold(memcg, false); + if (do_swap_account) + __mem_cgroup_threshold(memcg, true); + + memcg = parent_mem_cgroup(memcg); + } +} + +static int compare_thresholds(const void *a, const void *b) +{ + const struct mem_cgroup_threshold *_a = a; + const struct mem_cgroup_threshold *_b = b; + + if (_a->threshold > _b->threshold) + return 1; + + if (_a->threshold < _b->threshold) + return -1; + + return 0; +} + +static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg) +{ + struct mem_cgroup_eventfd_list *ev; + + spin_lock(&memcg_oom_lock); + + list_for_each_entry(ev, &memcg->oom_notify, list) + eventfd_signal(ev->eventfd, 1); + + spin_unlock(&memcg_oom_lock); + return 0; +} + +static void mem_cgroup_oom_notify(struct mem_cgroup *memcg) +{ + struct mem_cgroup *iter; + + for_each_mem_cgroup_tree(iter, memcg) + mem_cgroup_oom_notify_cb(iter); +} + +static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd, const char *args, enum res_type type) +{ + struct mem_cgroup_thresholds *thresholds; + struct mem_cgroup_threshold_ary *new; + unsigned long threshold; + unsigned long usage; + int i, size, ret; + + ret = page_counter_memparse(args, "-1", &threshold); + if (ret) + return ret; + + mutex_lock(&memcg->thresholds_lock); + + if (type == _MEM) { + thresholds = &memcg->thresholds; + usage = mem_cgroup_usage(memcg, false); + } else if (type == _MEMSWAP) { + thresholds = &memcg->memsw_thresholds; + usage = mem_cgroup_usage(memcg, true); + } else + BUG(); + + /* Check if a threshold crossed before adding a new one */ + if (thresholds->primary) + __mem_cgroup_threshold(memcg, type == _MEMSWAP); + + size = thresholds->primary ? thresholds->primary->size + 1 : 1; + + /* Allocate memory for new array of thresholds */ + new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold), + GFP_KERNEL); + if (!new) { + ret = -ENOMEM; + goto unlock; + } + new->size = size; + + /* Copy thresholds (if any) to new array */ + if (thresholds->primary) { + memcpy(new->entries, thresholds->primary->entries, (size - 1) * + sizeof(struct mem_cgroup_threshold)); + } + + /* Add new threshold */ + new->entries[size - 1].eventfd = eventfd; + new->entries[size - 1].threshold = threshold; + + /* Sort thresholds. Registering of new threshold isn't time-critical */ + sort(new->entries, size, sizeof(struct mem_cgroup_threshold), + compare_thresholds, NULL); + + /* Find current threshold */ + new->current_threshold = -1; + for (i = 0; i < size; i++) { + if (new->entries[i].threshold <= usage) { + /* + * new->current_threshold will not be used until + * rcu_assign_pointer(), so it's safe to increment + * it here. + */ + ++new->current_threshold; + } else + break; + } + + /* Free old spare buffer and save old primary buffer as spare */ + kfree(thresholds->spare); + thresholds->spare = thresholds->primary; + + rcu_assign_pointer(thresholds->primary, new); + + /* To be sure that nobody uses thresholds */ + synchronize_rcu(); + +unlock: + mutex_unlock(&memcg->thresholds_lock); + + return ret; +} + +static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd, const char *args) +{ + return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM); +} + +static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd, const char *args) +{ + return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP); +} + +static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd, enum res_type type) +{ + struct mem_cgroup_thresholds *thresholds; + struct mem_cgroup_threshold_ary *new; + unsigned long usage; + int i, j, size; + + mutex_lock(&memcg->thresholds_lock); + + if (type == _MEM) { + thresholds = &memcg->thresholds; + usage = mem_cgroup_usage(memcg, false); + } else if (type == _MEMSWAP) { + thresholds = &memcg->memsw_thresholds; + usage = mem_cgroup_usage(memcg, true); + } else + BUG(); + + if (!thresholds->primary) + goto unlock; + + /* Check if a threshold crossed before removing */ + __mem_cgroup_threshold(memcg, type == _MEMSWAP); + + /* Calculate new number of threshold */ + size = 0; + for (i = 0; i < thresholds->primary->size; i++) { + if (thresholds->primary->entries[i].eventfd != eventfd) + size++; + } + + new = thresholds->spare; + + /* Set thresholds array to NULL if we don't have thresholds */ + if (!size) { + kfree(new); + new = NULL; + goto swap_buffers; + } + + new->size = size; + + /* Copy thresholds and find current threshold */ + new->current_threshold = -1; + for (i = 0, j = 0; i < thresholds->primary->size; i++) { + if (thresholds->primary->entries[i].eventfd == eventfd) + continue; + + new->entries[j] = thresholds->primary->entries[i]; + if (new->entries[j].threshold <= usage) { + /* + * new->current_threshold will not be used + * until rcu_assign_pointer(), so it's safe to increment + * it here. + */ + ++new->current_threshold; + } + j++; + } + +swap_buffers: + /* Swap primary and spare array */ + thresholds->spare = thresholds->primary; + /* If all events are unregistered, free the spare array */ + if (!new) { + kfree(thresholds->spare); + thresholds->spare = NULL; + } + + rcu_assign_pointer(thresholds->primary, new); + + /* To be sure that nobody uses thresholds */ + synchronize_rcu(); +unlock: + mutex_unlock(&memcg->thresholds_lock); +} + +static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd) +{ + return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM); +} + +static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd) +{ + return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP); +} + +static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd, const char *args) +{ + struct mem_cgroup_eventfd_list *event; + + event = kmalloc(sizeof(*event), GFP_KERNEL); + if (!event) + return -ENOMEM; + + spin_lock(&memcg_oom_lock); + + event->eventfd = eventfd; + list_add(&event->list, &memcg->oom_notify); + + /* already in OOM ? */ + if (atomic_read(&memcg->under_oom)) + eventfd_signal(eventfd, 1); + spin_unlock(&memcg_oom_lock); + + return 0; +} + +static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd) +{ + struct mem_cgroup_eventfd_list *ev, *tmp; + + spin_lock(&memcg_oom_lock); + + list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) { + if (ev->eventfd == eventfd) { + list_del(&ev->list); + kfree(ev); + } + } + + spin_unlock(&memcg_oom_lock); +} + +static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(sf)); + + seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable); + seq_printf(sf, "under_oom %d\n", (bool)atomic_read(&memcg->under_oom)); + return 0; +} + +static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css, + struct cftype *cft, u64 val) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + + /* cannot set to root cgroup and only 0 and 1 are allowed */ + if (!css->parent || !((val == 0) || (val == 1))) + return -EINVAL; + + memcg->oom_kill_disable = val; + if (!val) + memcg_oom_recover(memcg); + + return 0; +} + +#ifdef CONFIG_MEMCG_KMEM +static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss) +{ + int ret; + + ret = memcg_propagate_kmem(memcg); + if (ret) + return ret; + + return mem_cgroup_sockets_init(memcg, ss); +} + +static void memcg_deactivate_kmem(struct mem_cgroup *memcg) +{ + struct cgroup_subsys_state *css; + struct mem_cgroup *parent, *child; + int kmemcg_id; + + if (!memcg->kmem_acct_active) + return; + + /* + * Clear the 'active' flag before clearing memcg_caches arrays entries. + * Since we take the slab_mutex in memcg_deactivate_kmem_caches(), it + * guarantees no cache will be created for this cgroup after we are + * done (see memcg_create_kmem_cache()). + */ + memcg->kmem_acct_active = false; + + memcg_deactivate_kmem_caches(memcg); + + kmemcg_id = memcg->kmemcg_id; + BUG_ON(kmemcg_id < 0); + + parent = parent_mem_cgroup(memcg); + if (!parent) + parent = root_mem_cgroup; + + /* + * Change kmemcg_id of this cgroup and all its descendants to the + * parent's id, and then move all entries from this cgroup's list_lrus + * to ones of the parent. After we have finished, all list_lrus + * corresponding to this cgroup are guaranteed to remain empty. The + * ordering is imposed by list_lru_node->lock taken by + * memcg_drain_all_list_lrus(). + */ + css_for_each_descendant_pre(css, &memcg->css) { + child = mem_cgroup_from_css(css); + BUG_ON(child->kmemcg_id != kmemcg_id); + child->kmemcg_id = parent->kmemcg_id; + if (!memcg->use_hierarchy) + break; + } + memcg_drain_all_list_lrus(kmemcg_id, parent->kmemcg_id); + + memcg_free_cache_id(kmemcg_id); +} + +static void memcg_destroy_kmem(struct mem_cgroup *memcg) +{ + if (memcg->kmem_acct_activated) { + memcg_destroy_kmem_caches(memcg); + static_key_slow_dec(&memcg_kmem_enabled_key); + WARN_ON(page_counter_read(&memcg->kmem)); + } + mem_cgroup_sockets_destroy(memcg); +} +#else +static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss) +{ + return 0; +} + +static void memcg_deactivate_kmem(struct mem_cgroup *memcg) +{ +} + +static void memcg_destroy_kmem(struct mem_cgroup *memcg) +{ +} +#endif + +/* + * DO NOT USE IN NEW FILES. + * + * "cgroup.event_control" implementation. + * + * This is way over-engineered. It tries to support fully configurable + * events for each user. Such level of flexibility is completely + * unnecessary especially in the light of the planned unified hierarchy. + * + * Please deprecate this and replace with something simpler if at all + * possible. + */ + +/* + * Unregister event and free resources. + * + * Gets called from workqueue. + */ +static void memcg_event_remove(struct work_struct *work) +{ + struct mem_cgroup_event *event = + container_of(work, struct mem_cgroup_event, remove); + struct mem_cgroup *memcg = event->memcg; + + remove_wait_queue(event->wqh, &event->wait); + + event->unregister_event(memcg, event->eventfd); + + /* Notify userspace the event is going away. */ + eventfd_signal(event->eventfd, 1); + + eventfd_ctx_put(event->eventfd); + kfree(event); + css_put(&memcg->css); +} + +/* + * Gets called on POLLHUP on eventfd when user closes it. + * + * Called with wqh->lock held and interrupts disabled. + */ +static int memcg_event_wake(wait_queue_t *wait, unsigned mode, + int sync, void *key) +{ + struct mem_cgroup_event *event = + container_of(wait, struct mem_cgroup_event, wait); + struct mem_cgroup *memcg = event->memcg; + unsigned long flags = (unsigned long)key; + + if (flags & POLLHUP) { + /* + * If the event has been detached at cgroup removal, we + * can simply return knowing the other side will cleanup + * for us. + * + * We can't race against event freeing since the other + * side will require wqh->lock via remove_wait_queue(), + * which we hold. + */ + spin_lock(&memcg->event_list_lock); + if (!list_empty(&event->list)) { + list_del_init(&event->list); + /* + * We are in atomic context, but cgroup_event_remove() + * may sleep, so we have to call it in workqueue. + */ + schedule_work(&event->remove); + } + spin_unlock(&memcg->event_list_lock); + } + + return 0; +} + +static void memcg_event_ptable_queue_proc(struct file *file, + wait_queue_head_t *wqh, poll_table *pt) +{ + struct mem_cgroup_event *event = + container_of(pt, struct mem_cgroup_event, pt); + + event->wqh = wqh; + add_wait_queue(wqh, &event->wait); +} + +/* + * DO NOT USE IN NEW FILES. + * + * Parse input and register new cgroup event handler. + * + * Input must be in format '<event_fd> <control_fd> <args>'. + * Interpretation of args is defined by control file implementation. + */ +static ssize_t memcg_write_event_control(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct cgroup_subsys_state *css = of_css(of); + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + struct mem_cgroup_event *event; + struct cgroup_subsys_state *cfile_css; + unsigned int efd, cfd; + struct fd efile; + struct fd cfile; + const char *name; + char *endp; + int ret; + + buf = strstrip(buf); + + efd = simple_strtoul(buf, &endp, 10); + if (*endp != ' ') + return -EINVAL; + buf = endp + 1; + + cfd = simple_strtoul(buf, &endp, 10); + if ((*endp != ' ') && (*endp != '\0')) + return -EINVAL; + buf = endp + 1; + + event = kzalloc(sizeof(*event), GFP_KERNEL); + if (!event) + return -ENOMEM; + + event->memcg = memcg; + INIT_LIST_HEAD(&event->list); + init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc); + init_waitqueue_func_entry(&event->wait, memcg_event_wake); + INIT_WORK(&event->remove, memcg_event_remove); + + efile = fdget(efd); + if (!efile.file) { + ret = -EBADF; + goto out_kfree; + } + + event->eventfd = eventfd_ctx_fileget(efile.file); + if (IS_ERR(event->eventfd)) { + ret = PTR_ERR(event->eventfd); + goto out_put_efile; + } + + cfile = fdget(cfd); + if (!cfile.file) { + ret = -EBADF; + goto out_put_eventfd; + } + + /* the process need read permission on control file */ + /* AV: shouldn't we check that it's been opened for read instead? */ + ret = inode_permission(file_inode(cfile.file), MAY_READ); + if (ret < 0) + goto out_put_cfile; + + /* + * Determine the event callbacks and set them in @event. This used + * to be done via struct cftype but cgroup core no longer knows + * about these events. The following is crude but the whole thing + * is for compatibility anyway. + * + * DO NOT ADD NEW FILES. + */ + name = cfile.file->f_path.dentry->d_name.name; + + if (!strcmp(name, "memory.usage_in_bytes")) { + event->register_event = mem_cgroup_usage_register_event; + event->unregister_event = mem_cgroup_usage_unregister_event; + } else if (!strcmp(name, "memory.oom_control")) { + event->register_event = mem_cgroup_oom_register_event; + event->unregister_event = mem_cgroup_oom_unregister_event; + } else if (!strcmp(name, "memory.pressure_level")) { + event->register_event = vmpressure_register_event; + event->unregister_event = vmpressure_unregister_event; + } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) { + event->register_event = memsw_cgroup_usage_register_event; + event->unregister_event = memsw_cgroup_usage_unregister_event; + } else { + ret = -EINVAL; + goto out_put_cfile; + } + + /* + * Verify @cfile should belong to @css. Also, remaining events are + * automatically removed on cgroup destruction but the removal is + * asynchronous, so take an extra ref on @css. + */ + cfile_css = css_tryget_online_from_dir(cfile.file->f_path.dentry->d_parent, + &memory_cgrp_subsys); + ret = -EINVAL; + if (IS_ERR(cfile_css)) + goto out_put_cfile; + if (cfile_css != css) { + css_put(cfile_css); + goto out_put_cfile; + } + + ret = event->register_event(memcg, event->eventfd, buf); + if (ret) + goto out_put_css; + + efile.file->f_op->poll(efile.file, &event->pt); + + spin_lock(&memcg->event_list_lock); + list_add(&event->list, &memcg->event_list); + spin_unlock(&memcg->event_list_lock); + + fdput(cfile); + fdput(efile); + + return nbytes; + +out_put_css: + css_put(css); +out_put_cfile: + fdput(cfile); +out_put_eventfd: + eventfd_ctx_put(event->eventfd); +out_put_efile: + fdput(efile); +out_kfree: + kfree(event); + + return ret; +} + +static struct cftype mem_cgroup_legacy_files[] = { + { + .name = "usage_in_bytes", + .private = MEMFILE_PRIVATE(_MEM, RES_USAGE), + .read_u64 = mem_cgroup_read_u64, + }, + { + .name = "max_usage_in_bytes", + .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE), + .write = mem_cgroup_reset, + .read_u64 = mem_cgroup_read_u64, + }, + { + .name = "limit_in_bytes", + .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT), + .write = mem_cgroup_write, + .read_u64 = mem_cgroup_read_u64, + }, + { + .name = "soft_limit_in_bytes", + .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT), + .write = mem_cgroup_write, + .read_u64 = mem_cgroup_read_u64, + }, + { + .name = "failcnt", + .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT), + .write = mem_cgroup_reset, + .read_u64 = mem_cgroup_read_u64, + }, + { + .name = "stat", + .seq_show = memcg_stat_show, + }, + { + .name = "force_empty", + .write = mem_cgroup_force_empty_write, + }, + { + .name = "use_hierarchy", + .write_u64 = mem_cgroup_hierarchy_write, + .read_u64 = mem_cgroup_hierarchy_read, + }, + { + .name = "cgroup.event_control", /* XXX: for compat */ + .write = memcg_write_event_control, + .flags = CFTYPE_NO_PREFIX, + .mode = S_IWUGO, + }, + { + .name = "swappiness", + .read_u64 = mem_cgroup_swappiness_read, + .write_u64 = mem_cgroup_swappiness_write, + }, + { + .name = "move_charge_at_immigrate", + .read_u64 = mem_cgroup_move_charge_read, + .write_u64 = mem_cgroup_move_charge_write, + }, + { + .name = "oom_control", + .seq_show = mem_cgroup_oom_control_read, + .write_u64 = mem_cgroup_oom_control_write, + .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL), + }, + { + .name = "pressure_level", + }, +#ifdef CONFIG_NUMA + { + .name = "numa_stat", + .seq_show = memcg_numa_stat_show, + }, +#endif +#ifdef CONFIG_MEMCG_KMEM + { + .name = "kmem.limit_in_bytes", + .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT), + .write = mem_cgroup_write, + .read_u64 = mem_cgroup_read_u64, + }, + { + .name = "kmem.usage_in_bytes", + .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE), + .read_u64 = mem_cgroup_read_u64, + }, + { + .name = "kmem.failcnt", + .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT), + .write = mem_cgroup_reset, + .read_u64 = mem_cgroup_read_u64, + }, + { + .name = "kmem.max_usage_in_bytes", + .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE), + .write = mem_cgroup_reset, + .read_u64 = mem_cgroup_read_u64, + }, +#ifdef CONFIG_SLABINFO + { + .name = "kmem.slabinfo", + .seq_start = slab_start, + .seq_next = slab_next, + .seq_stop = slab_stop, + .seq_show = memcg_slab_show, + }, +#endif +#endif + { }, /* terminate */ +}; + +static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node) +{ + struct mem_cgroup_per_node *pn; + struct mem_cgroup_per_zone *mz; + int zone, tmp = node; + /* + * This routine is called against possible nodes. + * But it's BUG to call kmalloc() against offline node. + * + * TODO: this routine can waste much memory for nodes which will + * never be onlined. It's better to use memory hotplug callback + * function. + */ + if (!node_state(node, N_NORMAL_MEMORY)) + tmp = -1; + pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp); + if (!pn) + return 1; + + for (zone = 0; zone < MAX_NR_ZONES; zone++) { + mz = &pn->zoneinfo[zone]; + lruvec_init(&mz->lruvec); + mz->usage_in_excess = 0; + mz->on_tree = false; + mz->memcg = memcg; + } + memcg->nodeinfo[node] = pn; + return 0; +} + +static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node) +{ + kfree(memcg->nodeinfo[node]); +} + +static struct mem_cgroup *mem_cgroup_alloc(void) +{ + struct mem_cgroup *memcg; + size_t size; + + size = sizeof(struct mem_cgroup); + size += nr_node_ids * sizeof(struct mem_cgroup_per_node *); + + memcg = kzalloc(size, GFP_KERNEL); + if (!memcg) + return NULL; + + memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu); + if (!memcg->stat) + goto out_free; + spin_lock_init(&memcg->pcp_counter_lock); + return memcg; + +out_free: + kfree(memcg); + return NULL; +} + +/* + * At destroying mem_cgroup, references from swap_cgroup can remain. + * (scanning all at force_empty is too costly...) + * + * Instead of clearing all references at force_empty, we remember + * the number of reference from swap_cgroup and free mem_cgroup when + * it goes down to 0. + * + * Removal of cgroup itself succeeds regardless of refs from swap. + */ + +static void __mem_cgroup_free(struct mem_cgroup *memcg) +{ + int node; + + mem_cgroup_remove_from_trees(memcg); + + for_each_node(node) + free_mem_cgroup_per_zone_info(memcg, node); + + free_percpu(memcg->stat); + kfree(memcg); +} + +/* + * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled. + */ +struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg) +{ + if (!memcg->memory.parent) + return NULL; + return mem_cgroup_from_counter(memcg->memory.parent, memory); +} +EXPORT_SYMBOL(parent_mem_cgroup); + +static struct cgroup_subsys_state * __ref +mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) +{ + struct mem_cgroup *memcg; + long error = -ENOMEM; + int node; + + memcg = mem_cgroup_alloc(); + if (!memcg) + return ERR_PTR(error); + + for_each_node(node) + if (alloc_mem_cgroup_per_zone_info(memcg, node)) + goto free_out; + + /* root ? */ + if (parent_css == NULL) { + root_mem_cgroup = memcg; + page_counter_init(&memcg->memory, NULL); + memcg->high = PAGE_COUNTER_MAX; + memcg->soft_limit = PAGE_COUNTER_MAX; + page_counter_init(&memcg->memsw, NULL); + page_counter_init(&memcg->kmem, NULL); + } + + memcg->last_scanned_node = MAX_NUMNODES; + INIT_LIST_HEAD(&memcg->oom_notify); + memcg->move_charge_at_immigrate = 0; + mutex_init(&memcg->thresholds_lock); + spin_lock_init(&memcg->move_lock); + vmpressure_init(&memcg->vmpressure); + INIT_LIST_HEAD(&memcg->event_list); + spin_lock_init(&memcg->event_list_lock); +#ifdef CONFIG_MEMCG_KMEM + memcg->kmemcg_id = -1; +#endif + + return &memcg->css; + +free_out: + __mem_cgroup_free(memcg); + return ERR_PTR(error); +} + +static int +mem_cgroup_css_online(struct cgroup_subsys_state *css) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + struct mem_cgroup *parent = mem_cgroup_from_css(css->parent); + int ret; + + if (css->id > MEM_CGROUP_ID_MAX) + return -ENOSPC; + + if (!parent) + return 0; + + mutex_lock(&memcg_create_mutex); + + memcg->use_hierarchy = parent->use_hierarchy; + memcg->oom_kill_disable = parent->oom_kill_disable; + memcg->swappiness = mem_cgroup_swappiness(parent); + + if (parent->use_hierarchy) { + page_counter_init(&memcg->memory, &parent->memory); + memcg->high = PAGE_COUNTER_MAX; + memcg->soft_limit = PAGE_COUNTER_MAX; + page_counter_init(&memcg->memsw, &parent->memsw); + page_counter_init(&memcg->kmem, &parent->kmem); + + /* + * No need to take a reference to the parent because cgroup + * core guarantees its existence. + */ + } else { + page_counter_init(&memcg->memory, NULL); + memcg->high = PAGE_COUNTER_MAX; + memcg->soft_limit = PAGE_COUNTER_MAX; + page_counter_init(&memcg->memsw, NULL); + page_counter_init(&memcg->kmem, NULL); + /* + * Deeper hierachy with use_hierarchy == false doesn't make + * much sense so let cgroup subsystem know about this + * unfortunate state in our controller. + */ + if (parent != root_mem_cgroup) + memory_cgrp_subsys.broken_hierarchy = true; + } + mutex_unlock(&memcg_create_mutex); + + ret = memcg_init_kmem(memcg, &memory_cgrp_subsys); + if (ret) + return ret; + + /* + * Make sure the memcg is initialized: mem_cgroup_iter() + * orders reading memcg->initialized against its callers + * reading the memcg members. + */ + smp_store_release(&memcg->initialized, 1); + + return 0; +} + +static void mem_cgroup_css_offline(struct cgroup_subsys_state *css) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + struct mem_cgroup_event *event, *tmp; + + /* + * Unregister events and notify userspace. + * Notify userspace about cgroup removing only after rmdir of cgroup + * directory to avoid race between userspace and kernelspace. + */ + spin_lock(&memcg->event_list_lock); + list_for_each_entry_safe(event, tmp, &memcg->event_list, list) { + list_del_init(&event->list); + schedule_work(&event->remove); + } + spin_unlock(&memcg->event_list_lock); + + vmpressure_cleanup(&memcg->vmpressure); + + memcg_deactivate_kmem(memcg); +} + +static void mem_cgroup_css_free(struct cgroup_subsys_state *css) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + + memcg_destroy_kmem(memcg); + __mem_cgroup_free(memcg); +} + +/** + * mem_cgroup_css_reset - reset the states of a mem_cgroup + * @css: the target css + * + * Reset the states of the mem_cgroup associated with @css. This is + * invoked when the userland requests disabling on the default hierarchy + * but the memcg is pinned through dependency. The memcg should stop + * applying policies and should revert to the vanilla state as it may be + * made visible again. + * + * The current implementation only resets the essential configurations. + * This needs to be expanded to cover all the visible parts. + */ +static void mem_cgroup_css_reset(struct cgroup_subsys_state *css) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + + mem_cgroup_resize_limit(memcg, PAGE_COUNTER_MAX); + mem_cgroup_resize_memsw_limit(memcg, PAGE_COUNTER_MAX); + memcg_update_kmem_limit(memcg, PAGE_COUNTER_MAX); + memcg->low = 0; + memcg->high = PAGE_COUNTER_MAX; + memcg->soft_limit = PAGE_COUNTER_MAX; +} + +#ifdef CONFIG_MMU +/* Handlers for move charge at task migration. */ +static int mem_cgroup_do_precharge(unsigned long count) +{ + int ret; + + /* Try a single bulk charge without reclaim first */ + ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_WAIT, count); + if (!ret) { + mc.precharge += count; + return ret; + } + if (ret == -EINTR) { + cancel_charge(root_mem_cgroup, count); + return ret; + } + + /* Try charges one by one with reclaim */ + while (count--) { + ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_NORETRY, 1); + /* + * In case of failure, any residual charges against + * mc.to will be dropped by mem_cgroup_clear_mc() + * later on. However, cancel any charges that are + * bypassed to root right away or they'll be lost. + */ + if (ret == -EINTR) + cancel_charge(root_mem_cgroup, 1); + if (ret) + return ret; + mc.precharge++; + cond_resched(); + } + return 0; +} + +/** + * get_mctgt_type - get target type of moving charge + * @vma: the vma the pte to be checked belongs + * @addr: the address corresponding to the pte to be checked + * @ptent: the pte to be checked + * @target: the pointer the target page or swap ent will be stored(can be NULL) + * + * Returns + * 0(MC_TARGET_NONE): if the pte is not a target for move charge. + * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for + * move charge. if @target is not NULL, the page is stored in target->page + * with extra refcnt got(Callers should handle it). + * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a + * target for charge migration. if @target is not NULL, the entry is stored + * in target->ent. + * + * Called with pte lock held. + */ +union mc_target { + struct page *page; + swp_entry_t ent; +}; + +enum mc_target_type { + MC_TARGET_NONE = 0, + MC_TARGET_PAGE, + MC_TARGET_SWAP, +}; + +static struct page *mc_handle_present_pte(struct vm_area_struct *vma, + unsigned long addr, pte_t ptent) +{ + struct page *page = vm_normal_page(vma, addr, ptent); + + if (!page || !page_mapped(page)) + return NULL; + if (PageAnon(page)) { + if (!(mc.flags & MOVE_ANON)) + return NULL; + } else { + if (!(mc.flags & MOVE_FILE)) + return NULL; + } + if (!get_page_unless_zero(page)) + return NULL; + + return page; +} + +#ifdef CONFIG_SWAP +static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, + unsigned long addr, pte_t ptent, swp_entry_t *entry) +{ + struct page *page = NULL; + swp_entry_t ent = pte_to_swp_entry(ptent); + + if (!(mc.flags & MOVE_ANON) || non_swap_entry(ent)) + return NULL; + /* + * Because lookup_swap_cache() updates some statistics counter, + * we call find_get_page() with swapper_space directly. + */ + page = find_get_page(swap_address_space(ent), ent.val); + if (do_swap_account) + entry->val = ent.val; + + return page; +} +#else +static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, + unsigned long addr, pte_t ptent, swp_entry_t *entry) +{ + return NULL; +} +#endif + +static struct page *mc_handle_file_pte(struct vm_area_struct *vma, + unsigned long addr, pte_t ptent, swp_entry_t *entry) +{ + struct page *page = NULL; + struct address_space *mapping; + pgoff_t pgoff; + + if (!vma->vm_file) /* anonymous vma */ + return NULL; + if (!(mc.flags & MOVE_FILE)) + return NULL; + + mapping = vma->vm_file->f_mapping; + pgoff = linear_page_index(vma, addr); + + /* page is moved even if it's not RSS of this task(page-faulted). */ +#ifdef CONFIG_SWAP + /* shmem/tmpfs may report page out on swap: account for that too. */ + if (shmem_mapping(mapping)) { + page = find_get_entry(mapping, pgoff); + if (radix_tree_exceptional_entry(page)) { + swp_entry_t swp = radix_to_swp_entry(page); + if (do_swap_account) + *entry = swp; + page = find_get_page(swap_address_space(swp), swp.val); + } + } else + page = find_get_page(mapping, pgoff); +#else + page = find_get_page(mapping, pgoff); +#endif + return page; +} + +/** + * mem_cgroup_move_account - move account of the page + * @page: the page + * @nr_pages: number of regular pages (>1 for huge pages) + * @from: mem_cgroup which the page is moved from. + * @to: mem_cgroup which the page is moved to. @from != @to. + * + * The caller must confirm following. + * - page is not on LRU (isolate_page() is useful.) + * - compound_lock is held when nr_pages > 1 + * + * This function doesn't do "charge" to new cgroup and doesn't do "uncharge" + * from old cgroup. + */ +static int mem_cgroup_move_account(struct page *page, + unsigned int nr_pages, + struct mem_cgroup *from, + struct mem_cgroup *to) +{ + unsigned long flags; + int ret; + + VM_BUG_ON(from == to); + VM_BUG_ON_PAGE(PageLRU(page), page); + /* + * The page is isolated from LRU. So, collapse function + * will not handle this page. But page splitting can happen. + * Do this check under compound_page_lock(). The caller should + * hold it. + */ + ret = -EBUSY; + if (nr_pages > 1 && !PageTransHuge(page)) + goto out; + + /* + * Prevent mem_cgroup_migrate() from looking at page->mem_cgroup + * of its source page while we change it: page migration takes + * both pages off the LRU, but page cache replacement doesn't. + */ + if (!trylock_page(page)) + goto out; + + ret = -EINVAL; + if (page->mem_cgroup != from) + goto out_unlock; + + spin_lock_irqsave(&from->move_lock, flags); + + if (!PageAnon(page) && page_mapped(page)) { + __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], + nr_pages); + __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], + nr_pages); + } + + if (PageWriteback(page)) { + __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK], + nr_pages); + __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_WRITEBACK], + nr_pages); + } + + /* + * It is safe to change page->mem_cgroup here because the page + * is referenced, charged, and isolated - we can't race with + * uncharging, charging, migration, or LRU putback. + */ + + /* caller should have done css_get */ + page->mem_cgroup = to; + spin_unlock_irqrestore(&from->move_lock, flags); + + ret = 0; + + local_lock_irq(event_lock); + mem_cgroup_charge_statistics(to, page, nr_pages); + memcg_check_events(to, page); + mem_cgroup_charge_statistics(from, page, -nr_pages); + memcg_check_events(from, page); + local_unlock_irq(event_lock); +out_unlock: + unlock_page(page); +out: + return ret; +} + +static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma, + unsigned long addr, pte_t ptent, union mc_target *target) +{ + struct page *page = NULL; + enum mc_target_type ret = MC_TARGET_NONE; + swp_entry_t ent = { .val = 0 }; + + if (pte_present(ptent)) + page = mc_handle_present_pte(vma, addr, ptent); + else if (is_swap_pte(ptent)) + page = mc_handle_swap_pte(vma, addr, ptent, &ent); + else if (pte_none(ptent)) + page = mc_handle_file_pte(vma, addr, ptent, &ent); + + if (!page && !ent.val) + return ret; + if (page) { + /* + * Do only loose check w/o serialization. + * mem_cgroup_move_account() checks the page is valid or + * not under LRU exclusion. + */ + if (page->mem_cgroup == mc.from) { + ret = MC_TARGET_PAGE; + if (target) + target->page = page; + } + if (!ret || !target) + put_page(page); + } + /* There is a swap entry and a page doesn't exist or isn't charged */ + if (ent.val && !ret && + mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) { + ret = MC_TARGET_SWAP; + if (target) + target->ent = ent; + } + return ret; +} + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +/* + * We don't consider swapping or file mapped pages because THP does not + * support them for now. + * Caller should make sure that pmd_trans_huge(pmd) is true. + */ +static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma, + unsigned long addr, pmd_t pmd, union mc_target *target) +{ + struct page *page = NULL; + enum mc_target_type ret = MC_TARGET_NONE; + + page = pmd_page(pmd); + VM_BUG_ON_PAGE(!page || !PageHead(page), page); + if (!(mc.flags & MOVE_ANON)) + return ret; + if (page->mem_cgroup == mc.from) { + ret = MC_TARGET_PAGE; + if (target) { + get_page(page); + target->page = page; + } + } + return ret; +} +#else +static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma, + unsigned long addr, pmd_t pmd, union mc_target *target) +{ + return MC_TARGET_NONE; +} +#endif + +static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, + unsigned long addr, unsigned long end, + struct mm_walk *walk) +{ + struct vm_area_struct *vma = walk->vma; + pte_t *pte; + spinlock_t *ptl; + + if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { + if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE) + mc.precharge += HPAGE_PMD_NR; + spin_unlock(ptl); + return 0; + } + + if (pmd_trans_unstable(pmd)) + return 0; + pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + for (; addr != end; pte++, addr += PAGE_SIZE) + if (get_mctgt_type(vma, addr, *pte, NULL)) + mc.precharge++; /* increment precharge temporarily */ + pte_unmap_unlock(pte - 1, ptl); + cond_resched(); + + return 0; +} + +static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm) +{ + unsigned long precharge; + + struct mm_walk mem_cgroup_count_precharge_walk = { + .pmd_entry = mem_cgroup_count_precharge_pte_range, + .mm = mm, + }; + down_read(&mm->mmap_sem); + walk_page_range(0, ~0UL, &mem_cgroup_count_precharge_walk); + up_read(&mm->mmap_sem); + + precharge = mc.precharge; + mc.precharge = 0; + + return precharge; +} + +static int mem_cgroup_precharge_mc(struct mm_struct *mm) +{ + unsigned long precharge = mem_cgroup_count_precharge(mm); + + VM_BUG_ON(mc.moving_task); + mc.moving_task = current; + return mem_cgroup_do_precharge(precharge); +} + +/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */ +static void __mem_cgroup_clear_mc(void) +{ + struct mem_cgroup *from = mc.from; + struct mem_cgroup *to = mc.to; + + /* we must uncharge all the leftover precharges from mc.to */ + if (mc.precharge) { + cancel_charge(mc.to, mc.precharge); + mc.precharge = 0; + } + /* + * we didn't uncharge from mc.from at mem_cgroup_move_account(), so + * we must uncharge here. + */ + if (mc.moved_charge) { + cancel_charge(mc.from, mc.moved_charge); + mc.moved_charge = 0; + } + /* we must fixup refcnts and charges */ + if (mc.moved_swap) { + /* uncharge swap account from the old cgroup */ + if (!mem_cgroup_is_root(mc.from)) + page_counter_uncharge(&mc.from->memsw, mc.moved_swap); + + /* + * we charged both to->memory and to->memsw, so we + * should uncharge to->memory. + */ + if (!mem_cgroup_is_root(mc.to)) + page_counter_uncharge(&mc.to->memory, mc.moved_swap); + + css_put_many(&mc.from->css, mc.moved_swap); + + /* we've already done css_get(mc.to) */ + mc.moved_swap = 0; + } + memcg_oom_recover(from); + memcg_oom_recover(to); + wake_up_all(&mc.waitq); +} + +static void mem_cgroup_clear_mc(void) +{ + /* + * we must clear moving_task before waking up waiters at the end of + * task migration. + */ + mc.moving_task = NULL; + __mem_cgroup_clear_mc(); + spin_lock(&mc.lock); + mc.from = NULL; + mc.to = NULL; + spin_unlock(&mc.lock); +} + +static int mem_cgroup_can_attach(struct cgroup_subsys_state *css, + struct cgroup_taskset *tset) +{ + struct task_struct *p = cgroup_taskset_first(tset); + int ret = 0; + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + unsigned long move_flags; + + /* + * We are now commited to this value whatever it is. Changes in this + * tunable will only affect upcoming migrations, not the current one. + * So we need to save it, and keep it going. + */ + move_flags = READ_ONCE(memcg->move_charge_at_immigrate); + if (move_flags) { + struct mm_struct *mm; + struct mem_cgroup *from = mem_cgroup_from_task(p); + + VM_BUG_ON(from == memcg); + + mm = get_task_mm(p); + if (!mm) + return 0; + /* We move charges only when we move a owner of the mm */ + if (mm->owner == p) { + VM_BUG_ON(mc.from); + VM_BUG_ON(mc.to); + VM_BUG_ON(mc.precharge); + VM_BUG_ON(mc.moved_charge); + VM_BUG_ON(mc.moved_swap); + + spin_lock(&mc.lock); + mc.from = from; + mc.to = memcg; + mc.flags = move_flags; + spin_unlock(&mc.lock); + /* We set mc.moving_task later */ + + ret = mem_cgroup_precharge_mc(mm); + if (ret) + mem_cgroup_clear_mc(); + } + mmput(mm); + } + return ret; +} + +static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css, + struct cgroup_taskset *tset) +{ + if (mc.to) + mem_cgroup_clear_mc(); +} + +static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, + unsigned long addr, unsigned long end, + struct mm_walk *walk) +{ + int ret = 0; + struct vm_area_struct *vma = walk->vma; + pte_t *pte; + spinlock_t *ptl; + enum mc_target_type target_type; + union mc_target target; + struct page *page; + + /* + * We don't take compound_lock() here but no race with splitting thp + * happens because: + * - if pmd_trans_huge_lock() returns 1, the relevant thp is not + * under splitting, which means there's no concurrent thp split, + * - if another thread runs into split_huge_page() just after we + * entered this if-block, the thread must wait for page table lock + * to be unlocked in __split_huge_page_splitting(), where the main + * part of thp split is not executed yet. + */ + if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { + if (mc.precharge < HPAGE_PMD_NR) { + spin_unlock(ptl); + return 0; + } + target_type = get_mctgt_type_thp(vma, addr, *pmd, &target); + if (target_type == MC_TARGET_PAGE) { + page = target.page; + if (!isolate_lru_page(page)) { + if (!mem_cgroup_move_account(page, HPAGE_PMD_NR, + mc.from, mc.to)) { + mc.precharge -= HPAGE_PMD_NR; + mc.moved_charge += HPAGE_PMD_NR; + } + putback_lru_page(page); + } + put_page(page); + } + spin_unlock(ptl); + return 0; + } + + if (pmd_trans_unstable(pmd)) + return 0; +retry: + pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + for (; addr != end; addr += PAGE_SIZE) { + pte_t ptent = *(pte++); + swp_entry_t ent; + + if (!mc.precharge) + break; + + switch (get_mctgt_type(vma, addr, ptent, &target)) { + case MC_TARGET_PAGE: + page = target.page; + if (isolate_lru_page(page)) + goto put; + if (!mem_cgroup_move_account(page, 1, mc.from, mc.to)) { + mc.precharge--; + /* we uncharge from mc.from later. */ + mc.moved_charge++; + } + putback_lru_page(page); +put: /* get_mctgt_type() gets the page */ + put_page(page); + break; + case MC_TARGET_SWAP: + ent = target.ent; + if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) { + mc.precharge--; + /* we fixup refcnts and charges later. */ + mc.moved_swap++; + } + break; + default: + break; + } + } + pte_unmap_unlock(pte - 1, ptl); + cond_resched(); + + if (addr != end) { + /* + * We have consumed all precharges we got in can_attach(). + * We try charge one by one, but don't do any additional + * charges to mc.to if we have failed in charge once in attach() + * phase. + */ + ret = mem_cgroup_do_precharge(1); + if (!ret) + goto retry; + } + + return ret; +} + +static void mem_cgroup_move_charge(struct mm_struct *mm) +{ + struct mm_walk mem_cgroup_move_charge_walk = { + .pmd_entry = mem_cgroup_move_charge_pte_range, + .mm = mm, + }; + + lru_add_drain_all(); + /* + * Signal mem_cgroup_begin_page_stat() to take the memcg's + * move_lock while we're moving its pages to another memcg. + * Then wait for already started RCU-only updates to finish. + */ + atomic_inc(&mc.from->moving_account); + synchronize_rcu(); +retry: + if (unlikely(!down_read_trylock(&mm->mmap_sem))) { + /* + * Someone who are holding the mmap_sem might be waiting in + * waitq. So we cancel all extra charges, wake up all waiters, + * and retry. Because we cancel precharges, we might not be able + * to move enough charges, but moving charge is a best-effort + * feature anyway, so it wouldn't be a big problem. + */ + __mem_cgroup_clear_mc(); + cond_resched(); + goto retry; + } + /* + * When we have consumed all precharges and failed in doing + * additional charge, the page walk just aborts. + */ + walk_page_range(0, ~0UL, &mem_cgroup_move_charge_walk); + up_read(&mm->mmap_sem); + atomic_dec(&mc.from->moving_account); +} + +static void mem_cgroup_move_task(struct cgroup_subsys_state *css, + struct cgroup_taskset *tset) +{ + struct task_struct *p = cgroup_taskset_first(tset); + struct mm_struct *mm = get_task_mm(p); + + if (mm) { + if (mc.to) + mem_cgroup_move_charge(mm); + mmput(mm); + } + if (mc.to) + mem_cgroup_clear_mc(); +} +#else /* !CONFIG_MMU */ +static int mem_cgroup_can_attach(struct cgroup_subsys_state *css, + struct cgroup_taskset *tset) +{ + return 0; +} +static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css, + struct cgroup_taskset *tset) +{ +} +static void mem_cgroup_move_task(struct cgroup_subsys_state *css, + struct cgroup_taskset *tset) +{ +} +#endif + +/* + * Cgroup retains root cgroups across [un]mount cycles making it necessary + * to verify whether we're attached to the default hierarchy on each mount + * attempt. + */ +static void mem_cgroup_bind(struct cgroup_subsys_state *root_css) +{ + /* + * use_hierarchy is forced on the default hierarchy. cgroup core + * guarantees that @root doesn't have any children, so turning it + * on for the root memcg is enough. + */ + if (cgroup_on_dfl(root_css->cgroup)) + root_mem_cgroup->use_hierarchy = true; + else + root_mem_cgroup->use_hierarchy = false; +} + +static u64 memory_current_read(struct cgroup_subsys_state *css, + struct cftype *cft) +{ + return mem_cgroup_usage(mem_cgroup_from_css(css), false); +} + +static int memory_low_show(struct seq_file *m, void *v) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); + unsigned long low = READ_ONCE(memcg->low); + + if (low == PAGE_COUNTER_MAX) + seq_puts(m, "max\n"); + else + seq_printf(m, "%llu\n", (u64)low * PAGE_SIZE); + + return 0; +} + +static ssize_t memory_low_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + unsigned long low; + int err; + + buf = strstrip(buf); + err = page_counter_memparse(buf, "max", &low); + if (err) + return err; + + memcg->low = low; + + return nbytes; +} + +static int memory_high_show(struct seq_file *m, void *v) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); + unsigned long high = READ_ONCE(memcg->high); + + if (high == PAGE_COUNTER_MAX) + seq_puts(m, "max\n"); + else + seq_printf(m, "%llu\n", (u64)high * PAGE_SIZE); + + return 0; +} + +static ssize_t memory_high_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + unsigned long high; + int err; + + buf = strstrip(buf); + err = page_counter_memparse(buf, "max", &high); + if (err) + return err; + + memcg->high = high; + + return nbytes; +} + +static int memory_max_show(struct seq_file *m, void *v) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); + unsigned long max = READ_ONCE(memcg->memory.limit); + + if (max == PAGE_COUNTER_MAX) + seq_puts(m, "max\n"); + else + seq_printf(m, "%llu\n", (u64)max * PAGE_SIZE); + + return 0; +} + +static ssize_t memory_max_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + unsigned long max; + int err; + + buf = strstrip(buf); + err = page_counter_memparse(buf, "max", &max); + if (err) + return err; + + err = mem_cgroup_resize_limit(memcg, max); + if (err) + return err; + + return nbytes; +} + +static int memory_events_show(struct seq_file *m, void *v) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); + + seq_printf(m, "low %lu\n", mem_cgroup_read_events(memcg, MEMCG_LOW)); + seq_printf(m, "high %lu\n", mem_cgroup_read_events(memcg, MEMCG_HIGH)); + seq_printf(m, "max %lu\n", mem_cgroup_read_events(memcg, MEMCG_MAX)); + seq_printf(m, "oom %lu\n", mem_cgroup_read_events(memcg, MEMCG_OOM)); + + return 0; +} + +static struct cftype memory_files[] = { + { + .name = "current", + .read_u64 = memory_current_read, + }, + { + .name = "low", + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = memory_low_show, + .write = memory_low_write, + }, + { + .name = "high", + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = memory_high_show, + .write = memory_high_write, + }, + { + .name = "max", + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = memory_max_show, + .write = memory_max_write, + }, + { + .name = "events", + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = memory_events_show, + }, + { } /* terminate */ +}; + +struct cgroup_subsys memory_cgrp_subsys = { + .css_alloc = mem_cgroup_css_alloc, + .css_online = mem_cgroup_css_online, + .css_offline = mem_cgroup_css_offline, + .css_free = mem_cgroup_css_free, + .css_reset = mem_cgroup_css_reset, + .can_attach = mem_cgroup_can_attach, + .cancel_attach = mem_cgroup_cancel_attach, + .attach = mem_cgroup_move_task, + .bind = mem_cgroup_bind, + .dfl_cftypes = memory_files, + .legacy_cftypes = mem_cgroup_legacy_files, + .early_init = 0, +}; + +/** + * mem_cgroup_events - count memory events against a cgroup + * @memcg: the memory cgroup + * @idx: the event index + * @nr: the number of events to account for + */ +void mem_cgroup_events(struct mem_cgroup *memcg, + enum mem_cgroup_events_index idx, + unsigned int nr) +{ + this_cpu_add(memcg->stat->events[idx], nr); +} + +/** + * mem_cgroup_low - check if memory consumption is below the normal range + * @root: the highest ancestor to consider + * @memcg: the memory cgroup to check + * + * Returns %true if memory consumption of @memcg, and that of all + * configurable ancestors up to @root, is below the normal range. + */ +bool mem_cgroup_low(struct mem_cgroup *root, struct mem_cgroup *memcg) +{ + if (mem_cgroup_disabled()) + return false; + + /* + * The toplevel group doesn't have a configurable range, so + * it's never low when looked at directly, and it is not + * considered an ancestor when assessing the hierarchy. + */ + + if (memcg == root_mem_cgroup) + return false; + + if (page_counter_read(&memcg->memory) >= memcg->low) + return false; + + while (memcg != root) { + memcg = parent_mem_cgroup(memcg); + + if (memcg == root_mem_cgroup) + break; + + if (page_counter_read(&memcg->memory) >= memcg->low) + return false; + } + return true; +} + +/** + * mem_cgroup_try_charge - try charging a page + * @page: page to charge + * @mm: mm context of the victim + * @gfp_mask: reclaim mode + * @memcgp: charged memcg return + * + * Try to charge @page to the memcg that @mm belongs to, reclaiming + * pages according to @gfp_mask if necessary. + * + * Returns 0 on success, with *@memcgp pointing to the charged memcg. + * Otherwise, an error code is returned. + * + * After page->mapping has been set up, the caller must finalize the + * charge with mem_cgroup_commit_charge(). Or abort the transaction + * with mem_cgroup_cancel_charge() in case page instantiation fails. + */ +int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm, + gfp_t gfp_mask, struct mem_cgroup **memcgp) +{ + struct mem_cgroup *memcg = NULL; + unsigned int nr_pages = 1; + int ret = 0; + + if (mem_cgroup_disabled()) + goto out; + + if (PageSwapCache(page)) { + /* + * Every swap fault against a single page tries to charge the + * page, bail as early as possible. shmem_unuse() encounters + * already charged pages, too. The USED bit is protected by + * the page lock, which serializes swap cache removal, which + * in turn serializes uncharging. + */ + if (page->mem_cgroup) + goto out; + } + + if (PageTransHuge(page)) { + nr_pages <<= compound_order(page); + VM_BUG_ON_PAGE(!PageTransHuge(page), page); + } + + if (do_swap_account && PageSwapCache(page)) + memcg = try_get_mem_cgroup_from_page(page); + if (!memcg) + memcg = get_mem_cgroup_from_mm(mm); + + ret = try_charge(memcg, gfp_mask, nr_pages); + + css_put(&memcg->css); + + if (ret == -EINTR) { + memcg = root_mem_cgroup; + ret = 0; + } +out: + *memcgp = memcg; + return ret; +} + +/** + * mem_cgroup_commit_charge - commit a page charge + * @page: page to charge + * @memcg: memcg to charge the page to + * @lrucare: page might be on LRU already + * + * Finalize a charge transaction started by mem_cgroup_try_charge(), + * after page->mapping has been set up. This must happen atomically + * as part of the page instantiation, i.e. under the page table lock + * for anonymous pages, under the page lock for page and swap cache. + * + * In addition, the page must not be on the LRU during the commit, to + * prevent racing with task migration. If it might be, use @lrucare. + * + * Use mem_cgroup_cancel_charge() to cancel the transaction instead. + */ +void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg, + bool lrucare) +{ + unsigned int nr_pages = 1; + + VM_BUG_ON_PAGE(!page->mapping, page); + VM_BUG_ON_PAGE(PageLRU(page) && !lrucare, page); + + if (mem_cgroup_disabled()) + return; + /* + * Swap faults will attempt to charge the same page multiple + * times. But reuse_swap_page() might have removed the page + * from swapcache already, so we can't check PageSwapCache(). + */ + if (!memcg) + return; + + commit_charge(page, memcg, lrucare); + + if (PageTransHuge(page)) { + nr_pages <<= compound_order(page); + VM_BUG_ON_PAGE(!PageTransHuge(page), page); + } + + local_lock_irq(event_lock); + mem_cgroup_charge_statistics(memcg, page, nr_pages); + memcg_check_events(memcg, page); + local_unlock_irq(event_lock); + + if (do_swap_account && PageSwapCache(page)) { + swp_entry_t entry = { .val = page_private(page) }; + /* + * The swap entry might not get freed for a long time, + * let's not wait for it. The page already received a + * memory+swap charge, drop the swap entry duplicate. + */ + mem_cgroup_uncharge_swap(entry); + } +} + +/** + * mem_cgroup_cancel_charge - cancel a page charge + * @page: page to charge + * @memcg: memcg to charge the page to + * + * Cancel a charge transaction started by mem_cgroup_try_charge(). + */ +void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg) +{ + unsigned int nr_pages = 1; + + if (mem_cgroup_disabled()) + return; + /* + * Swap faults will attempt to charge the same page multiple + * times. But reuse_swap_page() might have removed the page + * from swapcache already, so we can't check PageSwapCache(). + */ + if (!memcg) + return; + + if (PageTransHuge(page)) { + nr_pages <<= compound_order(page); + VM_BUG_ON_PAGE(!PageTransHuge(page), page); + } + + cancel_charge(memcg, nr_pages); +} + +static void uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout, + unsigned long nr_anon, unsigned long nr_file, + unsigned long nr_huge, struct page *dummy_page) +{ + unsigned long nr_pages = nr_anon + nr_file; + unsigned long flags; + + if (!mem_cgroup_is_root(memcg)) { + page_counter_uncharge(&memcg->memory, nr_pages); + if (do_swap_account) + page_counter_uncharge(&memcg->memsw, nr_pages); + memcg_oom_recover(memcg); + } + + local_lock_irqsave(event_lock, flags); + __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS], nr_anon); + __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_CACHE], nr_file); + __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], nr_huge); + __this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT], pgpgout); + __this_cpu_add(memcg->stat->nr_page_events, nr_pages); + memcg_check_events(memcg, dummy_page); + local_unlock_irqrestore(event_lock, flags); + + if (!mem_cgroup_is_root(memcg)) + css_put_many(&memcg->css, nr_pages); +} + +static void uncharge_list(struct list_head *page_list) +{ + struct mem_cgroup *memcg = NULL; + unsigned long nr_anon = 0; + unsigned long nr_file = 0; + unsigned long nr_huge = 0; + unsigned long pgpgout = 0; + struct list_head *next; + struct page *page; + + next = page_list->next; + do { + unsigned int nr_pages = 1; + + page = list_entry(next, struct page, lru); + next = page->lru.next; + + VM_BUG_ON_PAGE(PageLRU(page), page); + VM_BUG_ON_PAGE(page_count(page), page); + + if (!page->mem_cgroup) + continue; + + /* + * Nobody should be changing or seriously looking at + * page->mem_cgroup at this point, we have fully + * exclusive access to the page. + */ + + if (memcg != page->mem_cgroup) { + if (memcg) { + uncharge_batch(memcg, pgpgout, nr_anon, nr_file, + nr_huge, page); + pgpgout = nr_anon = nr_file = nr_huge = 0; + } + memcg = page->mem_cgroup; + } + + if (PageTransHuge(page)) { + nr_pages <<= compound_order(page); + VM_BUG_ON_PAGE(!PageTransHuge(page), page); + nr_huge += nr_pages; + } + + if (PageAnon(page)) + nr_anon += nr_pages; + else + nr_file += nr_pages; + + page->mem_cgroup = NULL; + + pgpgout++; + } while (next != page_list); + + if (memcg) + uncharge_batch(memcg, pgpgout, nr_anon, nr_file, + nr_huge, page); +} + +/** + * mem_cgroup_uncharge - uncharge a page + * @page: page to uncharge + * + * Uncharge a page previously charged with mem_cgroup_try_charge() and + * mem_cgroup_commit_charge(). + */ +void mem_cgroup_uncharge(struct page *page) +{ + if (mem_cgroup_disabled()) + return; + + /* Don't touch page->lru of any random page, pre-check: */ + if (!page->mem_cgroup) + return; + + INIT_LIST_HEAD(&page->lru); + uncharge_list(&page->lru); +} + +/** + * mem_cgroup_uncharge_list - uncharge a list of page + * @page_list: list of pages to uncharge + * + * Uncharge a list of pages previously charged with + * mem_cgroup_try_charge() and mem_cgroup_commit_charge(). + */ +void mem_cgroup_uncharge_list(struct list_head *page_list) +{ + if (mem_cgroup_disabled()) + return; + + if (!list_empty(page_list)) + uncharge_list(page_list); +} + +/** + * mem_cgroup_migrate - migrate a charge to another page + * @oldpage: currently charged page + * @newpage: page to transfer the charge to + * @lrucare: either or both pages might be on the LRU already + * + * Migrate the charge from @oldpage to @newpage. + * + * Both pages must be locked, @newpage->mapping must be set up. + */ +void mem_cgroup_migrate(struct page *oldpage, struct page *newpage, + bool lrucare) +{ + struct mem_cgroup *memcg; + int isolated; + + VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage); + VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); + VM_BUG_ON_PAGE(!lrucare && PageLRU(oldpage), oldpage); + VM_BUG_ON_PAGE(!lrucare && PageLRU(newpage), newpage); + VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage); + VM_BUG_ON_PAGE(PageTransHuge(oldpage) != PageTransHuge(newpage), + newpage); + + if (mem_cgroup_disabled()) + return; + + /* Page cache replacement: new page already charged? */ + if (newpage->mem_cgroup) + return; + + /* + * Swapcache readahead pages can get migrated before being + * charged, and migration from compaction can happen to an + * uncharged page when the PFN walker finds a page that + * reclaim just put back on the LRU but has not released yet. + */ + memcg = oldpage->mem_cgroup; + if (!memcg) + return; + + if (lrucare) + lock_page_lru(oldpage, &isolated); + + oldpage->mem_cgroup = NULL; + + if (lrucare) + unlock_page_lru(oldpage, isolated); + + commit_charge(newpage, memcg, lrucare); +} + +/* + * subsys_initcall() for memory controller. + * + * Some parts like hotcpu_notifier() have to be initialized from this context + * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically + * everything that doesn't depend on a specific mem_cgroup structure should + * be initialized from here. + */ +static int __init mem_cgroup_init(void) +{ + int cpu, node; + + hotcpu_notifier(memcg_cpu_hotplug_callback, 0); + + for_each_possible_cpu(cpu) + INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work, + drain_local_stock); + + for_each_node(node) { + struct mem_cgroup_tree_per_node *rtpn; + int zone; + + rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, + node_online(node) ? node : NUMA_NO_NODE); + + for (zone = 0; zone < MAX_NR_ZONES; zone++) { + struct mem_cgroup_tree_per_zone *rtpz; + + rtpz = &rtpn->rb_tree_per_zone[zone]; + rtpz->rb_root = RB_ROOT; + spin_lock_init(&rtpz->lock); + } + soft_limit_tree.rb_tree_per_node[node] = rtpn; + } + + return 0; +} +subsys_initcall(mem_cgroup_init); + +#ifdef CONFIG_MEMCG_SWAP +/** + * mem_cgroup_swapout - transfer a memsw charge to swap + * @page: page whose memsw charge to transfer + * @entry: swap entry to move the charge to + * + * Transfer the memsw charge of @page to @entry. + */ +void mem_cgroup_swapout(struct page *page, swp_entry_t entry) +{ + struct mem_cgroup *memcg; + unsigned short oldid; + unsigned long flags; + + VM_BUG_ON_PAGE(PageLRU(page), page); + VM_BUG_ON_PAGE(page_count(page), page); + + if (!do_swap_account) + return; + + memcg = page->mem_cgroup; + + /* Readahead page, never charged */ + if (!memcg) + return; + + oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg)); + VM_BUG_ON_PAGE(oldid, page); + mem_cgroup_swap_statistics(memcg, true); + + page->mem_cgroup = NULL; + + if (!mem_cgroup_is_root(memcg)) + page_counter_uncharge(&memcg->memory, 1); + + local_lock_irqsave(event_lock, flags); + /* Caller disabled preemption with mapping->tree_lock */ + mem_cgroup_charge_statistics(memcg, page, -1); + memcg_check_events(memcg, page); + local_unlock_irqrestore(event_lock, flags); +} + +/** + * mem_cgroup_uncharge_swap - uncharge a swap entry + * @entry: swap entry to uncharge + * + * Drop the memsw charge associated with @entry. + */ +void mem_cgroup_uncharge_swap(swp_entry_t entry) +{ + struct mem_cgroup *memcg; + unsigned short id; + + if (!do_swap_account) + return; + + id = swap_cgroup_record(entry, 0); + rcu_read_lock(); + memcg = mem_cgroup_from_id(id); + if (memcg) { + if (!mem_cgroup_is_root(memcg)) + page_counter_uncharge(&memcg->memsw, 1); + mem_cgroup_swap_statistics(memcg, false); + css_put(&memcg->css); + } + rcu_read_unlock(); +} + +/* for remember boot option*/ +#ifdef CONFIG_MEMCG_SWAP_ENABLED +static int really_do_swap_account __initdata = 1; +#else +static int really_do_swap_account __initdata; +#endif + +static int __init enable_swap_account(char *s) +{ + if (!strcmp(s, "1")) + really_do_swap_account = 1; + else if (!strcmp(s, "0")) + really_do_swap_account = 0; + return 1; +} +__setup("swapaccount=", enable_swap_account); + +static struct cftype memsw_cgroup_files[] = { + { + .name = "memsw.usage_in_bytes", + .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), + .read_u64 = mem_cgroup_read_u64, + }, + { + .name = "memsw.max_usage_in_bytes", + .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE), + .write = mem_cgroup_reset, + .read_u64 = mem_cgroup_read_u64, + }, + { + .name = "memsw.limit_in_bytes", + .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT), + .write = mem_cgroup_write, + .read_u64 = mem_cgroup_read_u64, + }, + { + .name = "memsw.failcnt", + .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT), + .write = mem_cgroup_reset, + .read_u64 = mem_cgroup_read_u64, + }, + { }, /* terminate */ +}; + +static int __init mem_cgroup_swap_init(void) +{ + if (!mem_cgroup_disabled() && really_do_swap_account) { + do_swap_account = 1; + WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, + memsw_cgroup_files)); + } + return 0; +} +subsys_initcall(mem_cgroup_swap_init); + +#endif /* CONFIG_MEMCG_SWAP */ |