diff options
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 5661 |
1 files changed, 5661 insertions, 0 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c new file mode 100644 index 00000000..7685d4a0 --- /dev/null +++ b/mm/memcontrol.c @@ -0,0 +1,5661 @@ +/* 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 + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/res_counter.h> +#include <linux/memcontrol.h> +#include <linux/cgroup.h> +#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/sort.h> +#include <linux/fs.h> +#include <linux/seq_file.h> +#include <linux/vmalloc.h> +#include <linux/mm_inline.h> +#include <linux/page_cgroup.h> +#include <linux/cpu.h> +#include <linux/oom.h> +#include "internal.h" +#include <net/sock.h> +#include <net/tcp_memcontrol.h> + +#include <asm/uaccess.h> + +#include <trace/events/vmscan.h> + +struct cgroup_subsys mem_cgroup_subsys __read_mostly; +#define MEM_CGROUP_RECLAIM_RETRIES 5 +struct mem_cgroup *root_mem_cgroup __read_mostly; + +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP +/* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */ +int do_swap_account __read_mostly; + +/* for remember boot option*/ +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED +static int really_do_swap_account __initdata = 1; +#else +static int really_do_swap_account __initdata = 0; +#endif + +#else +#define do_swap_account (0) +#endif + + +/* + * Statistics for memory cgroup. + */ +enum mem_cgroup_stat_index { + /* + * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss. + */ + MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */ + MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */ + MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */ + MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */ + MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */ + MEM_CGROUP_STAT_NSTATS, +}; + +enum mem_cgroup_events_index { + MEM_CGROUP_EVENTS_PGPGIN, /* # of pages paged in */ + MEM_CGROUP_EVENTS_PGPGOUT, /* # of pages paged out */ + MEM_CGROUP_EVENTS_COUNT, /* # of pages paged in/out */ + MEM_CGROUP_EVENTS_PGFAULT, /* # of page-faults */ + MEM_CGROUP_EVENTS_PGMAJFAULT, /* # of major page-faults */ + MEM_CGROUP_EVENTS_NSTATS, +}; +/* + * 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[MEM_CGROUP_EVENTS_NSTATS]; + unsigned long targets[MEM_CGROUP_NTARGETS]; +}; + +struct mem_cgroup_reclaim_iter { + /* css_id of the last scanned hierarchy member */ + int 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 mem_cgroup_reclaim_iter reclaim_iter[DEF_PRIORITY + 1]; + + struct zone_reclaim_stat reclaim_stat; + struct rb_node tree_node; /* RB tree node */ + unsigned long long usage_in_excess;/* Set to the value by which */ + /* the soft limit is exceeded*/ + bool on_tree; + 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]; +}; + +struct mem_cgroup_lru_info { + struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES]; +}; + +/* + * 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; + u64 threshold; +}; + +/* For threshold */ +struct mem_cgroup_threshold_ary { + /* An array index points to threshold just below 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; +}; + +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. + * + * TODO: Add a water mark for the memory controller. Reclaim will begin when + * we hit the water mark. May be even add a low water mark, such that + * no reclaim occurs from a cgroup at it's low water mark, this is + * a feature that will be implemented much later in the future. + */ +struct mem_cgroup { + struct cgroup_subsys_state css; + /* + * the counter to account for memory usage + */ + struct res_counter res; + + union { + /* + * the counter to account for mem+swap usage. + */ + struct res_counter memsw; + + /* + * rcu_freeing is used only when freeing struct mem_cgroup, + * so put it into a union to avoid wasting more memory. + * It must be disjoint from the css field. It could be + * in a union with the res field, but res plays a much + * larger part in mem_cgroup life than memsw, and might + * be of interest, even at time of free, when debugging. + * So share rcu_head with the less interesting memsw. + */ + struct rcu_head rcu_freeing; + /* + * But when using vfree(), that cannot be done at + * interrupt time, so we must then queue the work. + */ + struct work_struct work_freeing; + }; + + /* + * Per cgroup active and inactive list, similar to the + * per zone LRU lists. + */ + struct mem_cgroup_lru_info info; + int last_scanned_node; +#if MAX_NUMNODES > 1 + nodemask_t scan_nodes; + atomic_t numainfo_events; + atomic_t numainfo_updating; +#endif + /* + * Should the accounting and control be hierarchical, per subtree? + */ + bool use_hierarchy; + + bool oom_lock; + atomic_t under_oom; + + atomic_t refcnt; + + int swappiness; + /* OOM-Killer disable */ + int oom_kill_disable; + + /* set when res.limit == memsw.limit */ + bool memsw_is_minimum; + + /* 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; + /* + * percpu counter. + */ + struct mem_cgroup_stat_cpu *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; + +#ifdef CONFIG_INET + struct tcp_memcontrol tcp_mem; +#endif +}; + +/* Stuffs for move charges at task migration. */ +/* + * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a + * left-shifted bitmap of these types. + */ +enum move_type { + MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */ + MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */ + NR_MOVE_TYPE, +}; + +/* "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 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), +}; + +static bool move_anon(void) +{ + return test_bit(MOVE_CHARGE_TYPE_ANON, + &mc.to->move_charge_at_immigrate); +} + +static bool move_file(void) +{ + return test_bit(MOVE_CHARGE_TYPE_FILE, + &mc.to->move_charge_at_immigrate); +} + +/* + * 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_MAPPED, + MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */ + MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */ + 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 */ +#define _MEM (0) +#define _MEMSWAP (1) +#define _OOM_TYPE (2) +#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) + +/* + * Reclaim flags for mem_cgroup_hierarchical_reclaim + */ +#define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0 +#define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT) +#define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1 +#define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT) + +static void mem_cgroup_get(struct mem_cgroup *memcg); +static void mem_cgroup_put(struct mem_cgroup *memcg); + +/* Writing them here to avoid exposing memcg's inner layout */ +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM +#include <net/sock.h> +#include <net/ip.h> + +static bool mem_cgroup_is_root(struct mem_cgroup *memcg); +void sock_update_memcg(struct sock *sk) +{ + if (mem_cgroup_sockets_enabled) { + struct mem_cgroup *memcg; + + 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)); + mem_cgroup_get(sk->sk_cgrp->memcg); + return; + } + + rcu_read_lock(); + memcg = mem_cgroup_from_task(current); + if (!mem_cgroup_is_root(memcg)) { + mem_cgroup_get(memcg); + sk->sk_cgrp = sk->sk_prot->proto_cgroup(memcg); + } + 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; + mem_cgroup_put(memcg); + } +} + +#ifdef CONFIG_INET +struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg) +{ + if (!memcg || mem_cgroup_is_root(memcg)) + return NULL; + + return &memcg->tcp_mem.cg_proto; +} +EXPORT_SYMBOL(tcp_proto_cgroup); +#endif /* CONFIG_INET */ +#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */ + +static void drain_all_stock_async(struct mem_cgroup *memcg); + +static struct mem_cgroup_per_zone * +mem_cgroup_zoneinfo(struct mem_cgroup *memcg, int nid, int zid) +{ + return &memcg->info.nodeinfo[nid]->zoneinfo[zid]; +} + +struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg) +{ + return &memcg->css; +} + +static struct mem_cgroup_per_zone * +page_cgroup_zoneinfo(struct mem_cgroup *memcg, struct page *page) +{ + int nid = page_to_nid(page); + int zid = page_zonenum(page); + + return mem_cgroup_zoneinfo(memcg, nid, zid); +} + +static struct mem_cgroup_tree_per_zone * +soft_limit_tree_node_zone(int nid, int zid) +{ + return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; +} + +static struct mem_cgroup_tree_per_zone * +soft_limit_tree_from_page(struct page *page) +{ + int nid = page_to_nid(page); + int zid = page_zonenum(page); + + return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; +} + +static void +__mem_cgroup_insert_exceeded(struct mem_cgroup *memcg, + struct mem_cgroup_per_zone *mz, + struct mem_cgroup_tree_per_zone *mctz, + unsigned long 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 *memcg, + 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 *memcg, + struct mem_cgroup_per_zone *mz, + struct mem_cgroup_tree_per_zone *mctz) +{ + spin_lock(&mctz->lock); + __mem_cgroup_remove_exceeded(memcg, mz, mctz); + spin_unlock(&mctz->lock); +} + + +static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page) +{ + unsigned long long excess; + struct mem_cgroup_per_zone *mz; + struct mem_cgroup_tree_per_zone *mctz; + int nid = page_to_nid(page); + int zid = page_zonenum(page); + 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_zoneinfo(memcg, nid, zid); + excess = res_counter_soft_limit_excess(&memcg->res); + /* + * We have to update the tree if mz is on RB-tree or + * mem is over its softlimit. + */ + if (excess || mz->on_tree) { + spin_lock(&mctz->lock); + /* if on-tree, remove it */ + if (mz->on_tree) + __mem_cgroup_remove_exceeded(memcg, mz, mctz); + /* + * Insert again. mz->usage_in_excess will be updated. + * If excess is 0, no tree ops. + */ + __mem_cgroup_insert_exceeded(memcg, mz, mctz, excess); + spin_unlock(&mctz->lock); + } + } +} + +static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg) +{ + int node, zone; + struct mem_cgroup_per_zone *mz; + struct mem_cgroup_tree_per_zone *mctz; + + for_each_node(node) { + for (zone = 0; zone < MAX_NR_ZONES; zone++) { + mz = mem_cgroup_zoneinfo(memcg, node, zone); + mctz = soft_limit_tree_node_zone(node, zone); + mem_cgroup_remove_exceeded(memcg, 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->memcg, mz, mctz); + if (!res_counter_soft_limit_excess(&mz->memcg->res) || + !css_tryget(&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(&mctz->lock); + mz = __mem_cgroup_largest_soft_limit_node(mctz); + spin_unlock(&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 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_SWAPOUT], val); +} + +static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg, + enum mem_cgroup_events_index idx) +{ + unsigned long val = 0; + int cpu; + + 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 + return val; +} + +static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, + bool anon, int nr_pages) +{ + preempt_disable(); + + /* + * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is + * counted as CACHE even if it's on ANON LRU. + */ + if (anon) + __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); + + /* 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->events[MEM_CGROUP_EVENTS_COUNT], nr_pages); + + preempt_enable(); +} + +unsigned long +mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid, + unsigned int lru_mask) +{ + struct mem_cgroup_per_zone *mz; + enum lru_list lru; + unsigned long ret = 0; + + mz = mem_cgroup_zoneinfo(memcg, nid, zid); + + for_each_lru(lru) { + if (BIT(lru) & lru_mask) + ret += mz->lru_size[lru]; + } + return ret; +} + +static unsigned long +mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg, + int nid, unsigned int lru_mask) +{ + u64 total = 0; + int zid; + + for (zid = 0; zid < MAX_NR_ZONES; zid++) + total += mem_cgroup_zone_nr_lru_pages(memcg, + nid, zid, lru_mask); + + return total; +} + +static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg, + unsigned int lru_mask) +{ + int nid; + u64 total = 0; + + for_each_node_state(nid, N_HIGH_MEMORY) + total += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask); + return total; +} + +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->events[MEM_CGROUP_EVENTS_COUNT]); + 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) +{ + preempt_disable(); + /* 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 + preempt_enable(); + + 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 + } else + preempt_enable(); +} + +struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) +{ + return container_of(cgroup_subsys_state(cont, + mem_cgroup_subsys_id), struct mem_cgroup, + css); +} + +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 container_of(task_subsys_state(p, mem_cgroup_subsys_id), + struct mem_cgroup, css); +} + +struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) +{ + struct mem_cgroup *memcg = NULL; + + if (!mm) + return NULL; + /* + * Because we have no locks, mm->owner's may be being moved to other + * cgroup. We use css_tryget() here even if this looks + * pessimistic (rather than adding locks here). + */ + rcu_read_lock(); + do { + memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); + if (unlikely(!memcg)) + break; + } while (!css_tryget(&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 mem_cgroup *memcg = NULL; + int id = 0; + + if (mem_cgroup_disabled()) + return NULL; + + if (!root) + root = root_mem_cgroup; + + if (prev && !reclaim) + id = css_id(&prev->css); + + if (prev && prev != root) + css_put(&prev->css); + + if (!root->use_hierarchy && root != root_mem_cgroup) { + if (prev) + return NULL; + return root; + } + + while (!memcg) { + struct mem_cgroup_reclaim_iter *uninitialized_var(iter); + struct cgroup_subsys_state *css; + + if (reclaim) { + int nid = zone_to_nid(reclaim->zone); + int zid = zone_idx(reclaim->zone); + struct mem_cgroup_per_zone *mz; + + mz = mem_cgroup_zoneinfo(root, nid, zid); + iter = &mz->reclaim_iter[reclaim->priority]; + if (prev && reclaim->generation != iter->generation) + return NULL; + id = iter->position; + } + + rcu_read_lock(); + css = css_get_next(&mem_cgroup_subsys, id + 1, &root->css, &id); + if (css) { + if (css == &root->css || css_tryget(css)) + memcg = container_of(css, + struct mem_cgroup, css); + } else + id = 0; + rcu_read_unlock(); + + if (reclaim) { + iter->position = id; + if (!css) + iter->generation++; + else if (!prev && memcg) + reclaim->generation = iter->generation; + } + + if (prev && !css) + return NULL; + } + 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)) + +static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg) +{ + return (memcg == root_mem_cgroup); +} + +void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx) +{ + struct mem_cgroup *memcg; + + if (!mm) + return; + + 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 + * @mem: 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; + + if (mem_cgroup_disabled()) + return &zone->lruvec; + + mz = mem_cgroup_zoneinfo(memcg, zone_to_nid(zone), zone_idx(zone)); + return &mz->lruvec; +} + +/* + * Following LRU functions are allowed to be used without PCG_LOCK. + * Operations are called by routine of global LRU independently from memcg. + * What we have to take care of here is validness of pc->mem_cgroup. + * + * Changes to pc->mem_cgroup happens when + * 1. charge + * 2. moving account + * In typical case, "charge" is done before add-to-lru. Exception is SwapCache. + * It is added to LRU before charge. + * If PCG_USED bit is not set, page_cgroup is not added to this private LRU. + * When moving account, the page is not on LRU. It's isolated. + */ + +/** + * mem_cgroup_lru_add_list - account for adding an lru page and return lruvec + * @zone: zone of the page + * @page: the page + * @lru: current lru + * + * This function accounts for @page being added to @lru, and returns + * the lruvec for the given @zone and the memcg @page is charged to. + * + * The callsite is then responsible for physically linking the page to + * the returned lruvec->lists[@lru]. + */ +struct lruvec *mem_cgroup_lru_add_list(struct zone *zone, struct page *page, + enum lru_list lru) +{ + struct mem_cgroup_per_zone *mz; + struct mem_cgroup *memcg; + struct page_cgroup *pc; + + if (mem_cgroup_disabled()) + return &zone->lruvec; + + pc = lookup_page_cgroup(page); + memcg = pc->mem_cgroup; + + /* + * Surreptitiously switch any uncharged page to root: + * an uncharged page off lru does nothing to secure + * its former mem_cgroup from sudden removal. + * + * Our caller holds lru_lock, and PageCgroupUsed is updated + * under page_cgroup lock: between them, they make all uses + * of pc->mem_cgroup safe. + */ + if (!PageCgroupUsed(pc) && memcg != root_mem_cgroup) + pc->mem_cgroup = memcg = root_mem_cgroup; + + mz = page_cgroup_zoneinfo(memcg, page); + /* compound_order() is stabilized through lru_lock */ + mz->lru_size[lru] += 1 << compound_order(page); + return &mz->lruvec; +} + +/** + * mem_cgroup_lru_del_list - account for removing an lru page + * @page: the page + * @lru: target lru + * + * This function accounts for @page being removed from @lru. + * + * The callsite is then responsible for physically unlinking + * @page->lru. + */ +void mem_cgroup_lru_del_list(struct page *page, enum lru_list lru) +{ + struct mem_cgroup_per_zone *mz; + struct mem_cgroup *memcg; + struct page_cgroup *pc; + + if (mem_cgroup_disabled()) + return; + + pc = lookup_page_cgroup(page); + memcg = pc->mem_cgroup; + VM_BUG_ON(!memcg); + mz = page_cgroup_zoneinfo(memcg, page); + /* huge page split is done under lru_lock. so, we have no races. */ + VM_BUG_ON(mz->lru_size[lru] < (1 << compound_order(page))); + mz->lru_size[lru] -= 1 << compound_order(page); +} + +void mem_cgroup_lru_del(struct page *page) +{ + mem_cgroup_lru_del_list(page, page_lru(page)); +} + +/** + * mem_cgroup_lru_move_lists - account for moving a page between lrus + * @zone: zone of the page + * @page: the page + * @from: current lru + * @to: target lru + * + * This function accounts for @page being moved between the lrus @from + * and @to, and returns the lruvec for the given @zone and the memcg + * @page is charged to. + * + * The callsite is then responsible for physically relinking + * @page->lru to the returned lruvec->lists[@to]. + */ +struct lruvec *mem_cgroup_lru_move_lists(struct zone *zone, + struct page *page, + enum lru_list from, + enum lru_list to) +{ + /* XXX: Optimize this, especially for @from == @to */ + mem_cgroup_lru_del_list(page, from); + return mem_cgroup_lru_add_list(zone, page, to); +} + +/* + * Checks whether given mem is same or in the root_mem_cgroup's + * hierarchy subtree + */ +static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, + struct mem_cgroup *memcg) +{ + if (root_memcg != memcg) { + return (root_memcg->use_hierarchy && + css_is_ancestor(&memcg->css, &root_memcg->css)); + } + + return true; +} + +int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg) +{ + int ret; + struct mem_cgroup *curr = NULL; + struct task_struct *p; + + p = find_lock_task_mm(task); + if (p) { + curr = try_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. + */ + task_lock(task); + curr = mem_cgroup_from_task(task); + if (curr) + css_get(&curr->css); + task_unlock(task); + } + if (!curr) + return 0; + /* + * We should check use_hierarchy of "memcg" not "curr". Because checking + * use_hierarchy of "curr" here make this function true if hierarchy is + * enabled in "curr" and "curr" is a child of "memcg" in *cgroup* + * hierarchy(even if use_hierarchy is disabled in "memcg"). + */ + ret = mem_cgroup_same_or_subtree(memcg, curr); + css_put(&curr->css); + return ret; +} + +int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg, struct zone *zone) +{ + unsigned long inactive_ratio; + int nid = zone_to_nid(zone); + int zid = zone_idx(zone); + unsigned long inactive; + unsigned long active; + unsigned long gb; + + inactive = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid, + BIT(LRU_INACTIVE_ANON)); + active = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid, + BIT(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; +} + +int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg, struct zone *zone) +{ + unsigned long active; + unsigned long inactive; + int zid = zone_idx(zone); + int nid = zone_to_nid(zone); + + inactive = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid, + BIT(LRU_INACTIVE_FILE)); + active = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid, + BIT(LRU_ACTIVE_FILE)); + + return (active > inactive); +} + +struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg, + struct zone *zone) +{ + int nid = zone_to_nid(zone); + int zid = zone_idx(zone); + struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid); + + return &mz->reclaim_stat; +} + +struct zone_reclaim_stat * +mem_cgroup_get_reclaim_stat_from_page(struct page *page) +{ + struct page_cgroup *pc; + struct mem_cgroup_per_zone *mz; + + if (mem_cgroup_disabled()) + return NULL; + + pc = lookup_page_cgroup(page); + if (!PageCgroupUsed(pc)) + return NULL; + /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ + smp_rmb(); + mz = page_cgroup_zoneinfo(pc->mem_cgroup, page); + return &mz->reclaim_stat; +} + +#define mem_cgroup_from_res_counter(counter, member) \ + container_of(counter, struct mem_cgroup, member) + +/** + * mem_cgroup_margin - calculate chargeable space of a memory cgroup + * @mem: 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 long margin; + + margin = res_counter_margin(&memcg->res); + if (do_swap_account) + margin = min(margin, res_counter_margin(&memcg->memsw)); + return margin >> PAGE_SHIFT; +} + +int mem_cgroup_swappiness(struct mem_cgroup *memcg) +{ + struct cgroup *cgrp = memcg->css.cgroup; + + /* root ? */ + if (cgrp->parent == NULL) + return vm_swappiness; + + return memcg->swappiness; +} + +/* + * memcg->moving_account is used for checking possibility that some thread is + * calling move_account(). When a thread on CPU-A starts moving pages under + * a memcg, other threads should check memcg->moving_account under + * rcu_read_lock(), like this: + * + * CPU-A CPU-B + * rcu_read_lock() + * memcg->moving_account+1 if (memcg->mocing_account) + * take heavy locks. + * synchronize_rcu() update something. + * rcu_read_unlock() + * start move here. + */ + +/* for quick checking without looking up memcg */ +atomic_t memcg_moving __read_mostly; + +static void mem_cgroup_start_move(struct mem_cgroup *memcg) +{ + atomic_inc(&memcg_moving); + atomic_inc(&memcg->moving_account); + synchronize_rcu(); +} + +static void mem_cgroup_end_move(struct mem_cgroup *memcg) +{ + /* + * Now, mem_cgroup_clear_mc() may call this function with NULL. + * We check NULL in callee rather than caller. + */ + if (memcg) { + atomic_dec(&memcg_moving); + atomic_dec(&memcg->moving_account); + } +} + +/* + * 2 routines for checking "mem" is under move_account() or not. + * + * mem_cgroup_stolen() - checking whether a cgroup is mc.from or not. This + * is used for avoiding races in accounting. If true, + * pc->mem_cgroup may be overwritten. + * + * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or + * under hierarchy of moving cgroups. This is for + * waiting at hith-memory prressure caused by "move". + */ + +static bool mem_cgroup_stolen(struct mem_cgroup *memcg) +{ + VM_BUG_ON(!rcu_read_lock_held()); + return atomic_read(&memcg->moving_account) > 0; +} + +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_same_or_subtree(memcg, from) + || mem_cgroup_same_or_subtree(memcg, to); +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; +} + +/* + * Take this lock when + * - a code tries to modify page's memcg while it's USED. + * - a code tries to modify page state accounting in a memcg. + * see mem_cgroup_stolen(), too. + */ +static void move_lock_mem_cgroup(struct mem_cgroup *memcg, + unsigned long *flags) +{ + spin_lock_irqsave(&memcg->move_lock, *flags); +} + +static void move_unlock_mem_cgroup(struct mem_cgroup *memcg, + unsigned long *flags) +{ + spin_unlock_irqrestore(&memcg->move_lock, *flags); +} + +/** + * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode. + * @memcg: The memory cgroup that went over limit + * @p: Task that is going to be killed + * + * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is + * enabled + */ +void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) +{ + struct cgroup *task_cgrp; + struct cgroup *mem_cgrp; + /* + * Need a buffer in BSS, can't rely on allocations. The code relies + * on the assumption that OOM is serialized for memory controller. + * If this assumption is broken, revisit this code. + */ + static char memcg_name[PATH_MAX]; + int ret; + + if (!memcg || !p) + return; + + rcu_read_lock(); + + mem_cgrp = memcg->css.cgroup; + task_cgrp = task_cgroup(p, mem_cgroup_subsys_id); + + ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX); + if (ret < 0) { + /* + * Unfortunately, we are unable to convert to a useful name + * But we'll still print out the usage information + */ + rcu_read_unlock(); + goto done; + } + rcu_read_unlock(); + + printk(KERN_INFO "Task in %s killed", memcg_name); + + rcu_read_lock(); + ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX); + if (ret < 0) { + rcu_read_unlock(); + goto done; + } + rcu_read_unlock(); + + /* + * Continues from above, so we don't need an KERN_ level + */ + printk(KERN_CONT " as a result of limit of %s\n", memcg_name); +done: + + printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n", + res_counter_read_u64(&memcg->res, RES_USAGE) >> 10, + res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10, + res_counter_read_u64(&memcg->res, RES_FAILCNT)); + printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, " + "failcnt %llu\n", + res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10, + res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10, + res_counter_read_u64(&memcg->memsw, RES_FAILCNT)); +} + +/* + * 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. + */ +u64 mem_cgroup_get_limit(struct mem_cgroup *memcg) +{ + u64 limit; + u64 memsw; + + limit = res_counter_read_u64(&memcg->res, RES_LIMIT); + limit += total_swap_pages << PAGE_SHIFT; + + memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT); + /* + * If memsw is finite and limits the amount of swap space available + * to this memcg, return that limit. + */ + return min(limit, memsw); +} + +static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg, + gfp_t gfp_mask, + unsigned long flags) +{ + unsigned long total = 0; + bool noswap = false; + int loop; + + if (flags & MEM_CGROUP_RECLAIM_NOSWAP) + noswap = true; + if (!(flags & MEM_CGROUP_RECLAIM_SHRINK) && memcg->memsw_is_minimum) + noswap = true; + + for (loop = 0; loop < MEM_CGROUP_MAX_RECLAIM_LOOPS; loop++) { + if (loop) + drain_all_stock_async(memcg); + total += try_to_free_mem_cgroup_pages(memcg, gfp_mask, noswap); + /* + * Allow limit shrinkers, which are triggered directly + * by userspace, to catch signals and stop reclaim + * after minimal progress, regardless of the margin. + */ + if (total && (flags & MEM_CGROUP_RECLAIM_SHRINK)) + break; + if (mem_cgroup_margin(memcg)) + break; + /* + * If nothing was reclaimed after two attempts, there + * may be no reclaimable pages in this hierarchy. + */ + if (loop && !total) + break; + } + return total; +} + +/** + * test_mem_cgroup_node_reclaimable + * @mem: 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; + +} +#if MAX_NUMNODES > 1 + +/* + * 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_HIGH_MEMORY]; + + for_each_node_mask(nid, node_states[N_HIGH_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; +} + +/* + * Check all nodes whether it contains reclaimable pages or not. + * For quick scan, we make use of scan_nodes. This will allow us to skip + * unused nodes. But scan_nodes is lazily updated and may not cotain + * enough new information. We need to do double check. + */ +bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap) +{ + int nid; + + /* + * quick check...making use of scan_node. + * We can skip unused nodes. + */ + if (!nodes_empty(memcg->scan_nodes)) { + for (nid = first_node(memcg->scan_nodes); + nid < MAX_NUMNODES; + nid = next_node(nid, memcg->scan_nodes)) { + + if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap)) + return true; + } + } + /* + * Check rest of nodes. + */ + for_each_node_state(nid, N_HIGH_MEMORY) { + if (node_isset(nid, memcg->scan_nodes)) + continue; + if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap)) + return true; + } + return false; +} + +#else +int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) +{ + return 0; +} + +bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap) +{ + return test_mem_cgroup_node_reclaimable(memcg, 0, noswap); +} +#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 = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT; + + 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; + } + if (!mem_cgroup_reclaimable(victim, false)) + continue; + total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false, + zone, &nr_scanned); + *total_scanned += nr_scanned; + if (!res_counter_soft_limit_excess(&root_memcg->res)) + break; + } + mem_cgroup_iter_break(root_memcg, victim); + return total; +} + +/* + * Check OOM-Killer is already running under our hierarchy. + * If someone is running, return false. + * Has to be called with memcg_oom_lock + */ +static bool mem_cgroup_oom_lock(struct mem_cgroup *memcg) +{ + struct mem_cgroup *iter, *failed = NULL; + + 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) + return true; + + /* + * 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; + } + return false; +} + +/* + * Has to be called with memcg_oom_lock + */ +static int mem_cgroup_oom_unlock(struct mem_cgroup *memcg) +{ + struct mem_cgroup *iter; + + for_each_mem_cgroup_tree(iter, memcg) + iter->oom_lock = false; + return 0; +} + +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 DEFINE_SPINLOCK(memcg_oom_lock); +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; + + /* + * Both of oom_wait_info->memcg and wake_memcg are stable under us. + * Then we can use css_is_ancestor without taking care of RCU. + */ + if (!mem_cgroup_same_or_subtree(oom_wait_memcg, wake_memcg) + && !mem_cgroup_same_or_subtree(wake_memcg, oom_wait_memcg)) + return 0; + return autoremove_wake_function(wait, mode, sync, arg); +} + +static void memcg_wakeup_oom(struct mem_cgroup *memcg) +{ + /* 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); +} + +/* + * try to call OOM killer. returns false if we should exit memory-reclaim loop. + */ +bool mem_cgroup_handle_oom(struct mem_cgroup *memcg, gfp_t mask, int order) +{ + struct oom_wait_info owait; + bool locked, need_to_kill; + + 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); + need_to_kill = true; + mem_cgroup_mark_under_oom(memcg); + + /* At first, try to OOM lock hierarchy under memcg.*/ + spin_lock(&memcg_oom_lock); + locked = mem_cgroup_oom_lock(memcg); + /* + * Even if signal_pending(), we can't quit charge() loop without + * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL + * under OOM is always welcomed, use TASK_KILLABLE here. + */ + prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE); + if (!locked || memcg->oom_kill_disable) + need_to_kill = false; + if (locked) + mem_cgroup_oom_notify(memcg); + spin_unlock(&memcg_oom_lock); + + if (need_to_kill) { + finish_wait(&memcg_oom_waitq, &owait.wait); + mem_cgroup_out_of_memory(memcg, mask, order); + } else { + schedule(); + finish_wait(&memcg_oom_waitq, &owait.wait); + } + spin_lock(&memcg_oom_lock); + if (locked) + mem_cgroup_oom_unlock(memcg); + memcg_wakeup_oom(memcg); + spin_unlock(&memcg_oom_lock); + + mem_cgroup_unmark_under_oom(memcg); + + if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current)) + return false; + /* Give chance to dying process */ + schedule_timeout_uninterruptible(1); + return true; +} + +/* + * Currently used to update mapped file statistics, but the routine can be + * generalized to update other statistics as well. + * + * Notes: Race condition + * + * We usually use page_cgroup_lock() for accessing page_cgroup member but + * it tends to be costly. But considering some conditions, we doesn't need + * to do so _always_. + * + * Considering "charge", lock_page_cgroup() is not required because all + * file-stat operations happen after a page is attached to radix-tree. There + * are no race with "charge". + * + * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup + * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even + * if there are race with "uncharge". Statistics itself is properly handled + * by flags. + * + * Considering "move", this is an only case we see a race. To make the race + * small, we check mm->moving_account and detect there are possibility of race + * If there is, we take a lock. + */ + +void __mem_cgroup_begin_update_page_stat(struct page *page, + bool *locked, unsigned long *flags) +{ + struct mem_cgroup *memcg; + struct page_cgroup *pc; + + pc = lookup_page_cgroup(page); +again: + memcg = pc->mem_cgroup; + if (unlikely(!memcg || !PageCgroupUsed(pc))) + return; + /* + * If this memory cgroup is not under account moving, we don't + * need to take move_lock_page_cgroup(). Because we already hold + * rcu_read_lock(), any calls to move_account will be delayed until + * rcu_read_unlock() if mem_cgroup_stolen() == true. + */ + if (!mem_cgroup_stolen(memcg)) + return; + + move_lock_mem_cgroup(memcg, flags); + if (memcg != pc->mem_cgroup || !PageCgroupUsed(pc)) { + move_unlock_mem_cgroup(memcg, flags); + goto again; + } + *locked = true; +} + +void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags) +{ + struct page_cgroup *pc = lookup_page_cgroup(page); + + /* + * It's guaranteed that pc->mem_cgroup never changes while + * lock is held because a routine modifies pc->mem_cgroup + * should take move_lock_page_cgroup(). + */ + move_unlock_mem_cgroup(pc->mem_cgroup, flags); +} + +void mem_cgroup_update_page_stat(struct page *page, + enum mem_cgroup_page_stat_item idx, int val) +{ + struct mem_cgroup *memcg; + struct page_cgroup *pc = lookup_page_cgroup(page); + unsigned long uninitialized_var(flags); + + if (mem_cgroup_disabled()) + return; + + memcg = pc->mem_cgroup; + if (unlikely(!memcg || !PageCgroupUsed(pc))) + return; + + switch (idx) { + case MEMCG_NR_FILE_MAPPED: + idx = MEM_CGROUP_STAT_FILE_MAPPED; + break; + default: + BUG(); + } + + 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); + +/* + * Try to consume stocked charge on this cpu. If success, one page is consumed + * from local stock and true is returned. If the stock is 0 or charges from a + * cgroup which is not current target, returns false. This stock will be + * refilled. + */ +static bool consume_stock(struct mem_cgroup *memcg) +{ + struct memcg_stock_pcp *stock; + bool ret = true; + + stock = &get_cpu_var(memcg_stock); + if (memcg == stock->cached && stock->nr_pages) + stock->nr_pages--; + else /* need to call res_counter_charge */ + ret = false; + put_cpu_var(memcg_stock); + return ret; +} + +/* + * Returns stocks cached in percpu to res_counter and reset cached information. + */ +static void drain_stock(struct memcg_stock_pcp *stock) +{ + struct mem_cgroup *old = stock->cached; + + if (stock->nr_pages) { + unsigned long bytes = stock->nr_pages * PAGE_SIZE; + + res_counter_uncharge(&old->res, bytes); + if (do_swap_account) + res_counter_uncharge(&old->memsw, bytes); + 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 = &__get_cpu_var(memcg_stock); + drain_stock(stock); + clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); +} + +/* + * Cache charges(val) which is from res_counter, 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 = &get_cpu_var(memcg_stock); + + if (stock->cached != memcg) { /* reset if necessary */ + drain_stock(stock); + stock->cached = memcg; + } + stock->nr_pages += nr_pages; + put_cpu_var(memcg_stock); +} + +/* + * Drains all per-CPU charge caches for given root_memcg resp. subtree + * of the hierarchy under it. sync flag says whether we should block + * until the work is done. + */ +static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync) +{ + int cpu, curcpu; + + /* Notify other cpus that system-wide "drain" is running */ + get_online_cpus(); + curcpu = get_cpu(); + 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_same_or_subtree(root_memcg, 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(); + + if (!sync) + goto out; + + for_each_online_cpu(cpu) { + struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); + if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) + flush_work(&stock->work); + } +out: + put_online_cpus(); +} + +/* + * Tries to drain stocked charges in other cpus. This function is asynchronous + * and just put a work per cpu for draining localy on each cpu. Caller can + * expects some charges will be back to res_counter later but cannot wait for + * it. + */ +static void drain_all_stock_async(struct mem_cgroup *root_memcg) +{ + /* + * If someone calls draining, avoid adding more kworker runs. + */ + if (!mutex_trylock(&percpu_charge_mutex)) + return; + drain_all_stock(root_memcg, false); + mutex_unlock(&percpu_charge_mutex); +} + +/* This is a synchronous drain interface. */ +static void drain_all_stock_sync(struct mem_cgroup *root_memcg) +{ + /* called when force_empty is called */ + mutex_lock(&percpu_charge_mutex); + drain_all_stock(root_memcg, true); + 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_DATA; 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 __cpuinit 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; +} + + +/* See __mem_cgroup_try_charge() for details */ +enum { + CHARGE_OK, /* success */ + CHARGE_RETRY, /* need to retry but retry is not bad */ + CHARGE_NOMEM, /* we can't do more. return -ENOMEM */ + CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */ + CHARGE_OOM_DIE, /* the current is killed because of OOM */ +}; + +static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, + unsigned int nr_pages, bool oom_check) +{ + unsigned long csize = nr_pages * PAGE_SIZE; + struct mem_cgroup *mem_over_limit; + struct res_counter *fail_res; + unsigned long flags = 0; + int ret; + + ret = res_counter_charge(&memcg->res, csize, &fail_res); + + if (likely(!ret)) { + if (!do_swap_account) + return CHARGE_OK; + ret = res_counter_charge(&memcg->memsw, csize, &fail_res); + if (likely(!ret)) + return CHARGE_OK; + + res_counter_uncharge(&memcg->res, csize); + mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw); + flags |= MEM_CGROUP_RECLAIM_NOSWAP; + } else + mem_over_limit = mem_cgroup_from_res_counter(fail_res, res); + /* + * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch + * of regular pages (CHARGE_BATCH), or a single regular page (1). + * + * Never reclaim on behalf of optional batching, retry with a + * single page instead. + */ + if (nr_pages == CHARGE_BATCH) + return CHARGE_RETRY; + + if (!(gfp_mask & __GFP_WAIT)) + return CHARGE_WOULDBLOCK; + + ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags); + if (mem_cgroup_margin(mem_over_limit) >= nr_pages) + return CHARGE_RETRY; + /* + * 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_pages == 1 && ret) + return CHARGE_RETRY; + + /* + * At task move, charge accounts can be doubly counted. So, it's + * better to wait until the end of task_move if something is going on. + */ + if (mem_cgroup_wait_acct_move(mem_over_limit)) + return CHARGE_RETRY; + + /* If we don't need to call oom-killer at el, return immediately */ + if (!oom_check) + return CHARGE_NOMEM; + /* check OOM */ + if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask, get_order(csize))) + return CHARGE_OOM_DIE; + + return CHARGE_RETRY; +} + +/* + * __mem_cgroup_try_charge() does + * 1. detect memcg to be charged against from passed *mm and *ptr, + * 2. update res_counter + * 3. call memory reclaim if necessary. + * + * In some special case, if the task is fatal, fatal_signal_pending() or + * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup + * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon + * as possible without any hazards. 2: all pages should have a valid + * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg + * pointer, that is treated as a charge to root_mem_cgroup. + * + * So __mem_cgroup_try_charge() will return + * 0 ... on success, filling *ptr with a valid memcg pointer. + * -ENOMEM ... charge failure because of resource limits. + * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup. + * + * Unlike the exported interface, an "oom" parameter is added. if oom==true, + * the oom-killer can be invoked. + */ +static int __mem_cgroup_try_charge(struct mm_struct *mm, + gfp_t gfp_mask, + unsigned int nr_pages, + struct mem_cgroup **ptr, + bool oom) +{ + unsigned int batch = max(CHARGE_BATCH, nr_pages); + int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; + struct mem_cgroup *memcg = NULL; + int ret; + + /* + * Unlike gloval-vm's OOM-kill, we're not in memory shortage + * in system level. So, allow to go ahead dying process in addition to + * MEMDIE process. + */ + if (unlikely(test_thread_flag(TIF_MEMDIE) + || fatal_signal_pending(current))) + goto bypass; + + /* + * We always charge the cgroup the mm_struct belongs to. + * The mm_struct's mem_cgroup changes on task migration if the + * thread group leader migrates. It's possible that mm is not + * set, if so charge the init_mm (happens for pagecache usage). + */ + if (!*ptr && !mm) + *ptr = root_mem_cgroup; +again: + if (*ptr) { /* css should be a valid one */ + memcg = *ptr; + VM_BUG_ON(css_is_removed(&memcg->css)); + if (mem_cgroup_is_root(memcg)) + goto done; + if (nr_pages == 1 && consume_stock(memcg)) + goto done; + css_get(&memcg->css); + } else { + struct task_struct *p; + + rcu_read_lock(); + p = rcu_dereference(mm->owner); + /* + * Because we don't have task_lock(), "p" can exit. + * In that case, "memcg" can point to root or p can be NULL with + * race with swapoff. Then, we have small risk of mis-accouning. + * But such kind of mis-account by race always happens because + * we don't have cgroup_mutex(). It's overkill and we allo that + * small race, here. + * (*) swapoff at el will charge against mm-struct not against + * task-struct. So, mm->owner can be NULL. + */ + memcg = mem_cgroup_from_task(p); + if (!memcg) + memcg = root_mem_cgroup; + if (mem_cgroup_is_root(memcg)) { + rcu_read_unlock(); + goto done; + } + if (nr_pages == 1 && consume_stock(memcg)) { + /* + * It seems dagerous to access memcg without css_get(). + * But considering how consume_stok works, it's not + * necessary. If consume_stock success, some charges + * from this memcg are cached on this cpu. So, we + * don't need to call css_get()/css_tryget() before + * calling consume_stock(). + */ + rcu_read_unlock(); + goto done; + } + /* after here, we may be blocked. we need to get refcnt */ + if (!css_tryget(&memcg->css)) { + rcu_read_unlock(); + goto again; + } + rcu_read_unlock(); + } + + do { + bool oom_check; + + /* If killed, bypass charge */ + if (fatal_signal_pending(current)) { + css_put(&memcg->css); + goto bypass; + } + + oom_check = false; + if (oom && !nr_oom_retries) { + oom_check = true; + nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; + } + + ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, oom_check); + switch (ret) { + case CHARGE_OK: + break; + case CHARGE_RETRY: /* not in OOM situation but retry */ + batch = nr_pages; + css_put(&memcg->css); + memcg = NULL; + goto again; + case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */ + css_put(&memcg->css); + goto nomem; + case CHARGE_NOMEM: /* OOM routine works */ + if (!oom) { + css_put(&memcg->css); + goto nomem; + } + /* If oom, we never return -ENOMEM */ + nr_oom_retries--; + break; + case CHARGE_OOM_DIE: /* Killed by OOM Killer */ + css_put(&memcg->css); + goto bypass; + } + } while (ret != CHARGE_OK); + + if (batch > nr_pages) + refill_stock(memcg, batch - nr_pages); + css_put(&memcg->css); +done: + *ptr = memcg; + return 0; +nomem: + *ptr = NULL; + return -ENOMEM; +bypass: + *ptr = root_mem_cgroup; + return -EINTR; +} + +/* + * Somemtimes we have to undo a charge we got by try_charge(). + * This function is for that and do uncharge, put css's refcnt. + * gotten by try_charge(). + */ +static void __mem_cgroup_cancel_charge(struct mem_cgroup *memcg, + unsigned int nr_pages) +{ + if (!mem_cgroup_is_root(memcg)) { + unsigned long bytes = nr_pages * PAGE_SIZE; + + res_counter_uncharge(&memcg->res, bytes); + if (do_swap_account) + res_counter_uncharge(&memcg->memsw, bytes); + } +} + +/* + * A helper function to get mem_cgroup from ID. must be called under + * rcu_read_lock(). The caller must check css_is_removed() or some if + * it's concern. (dropping refcnt from swap can be called against removed + * memcg.) + */ +static struct mem_cgroup *mem_cgroup_lookup(unsigned short id) +{ + struct cgroup_subsys_state *css; + + /* ID 0 is unused ID */ + if (!id) + return NULL; + css = css_lookup(&mem_cgroup_subsys, id); + if (!css) + return NULL; + return container_of(css, struct mem_cgroup, css); +} + +struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) +{ + struct mem_cgroup *memcg = NULL; + struct page_cgroup *pc; + unsigned short id; + swp_entry_t ent; + + VM_BUG_ON(!PageLocked(page)); + + pc = lookup_page_cgroup(page); + lock_page_cgroup(pc); + if (PageCgroupUsed(pc)) { + memcg = pc->mem_cgroup; + if (memcg && !css_tryget(&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_lookup(id); + if (memcg && !css_tryget(&memcg->css)) + memcg = NULL; + rcu_read_unlock(); + } + unlock_page_cgroup(pc); + return memcg; +} + +static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, + struct page *page, + unsigned int nr_pages, + enum charge_type ctype, + bool lrucare) +{ + struct page_cgroup *pc = lookup_page_cgroup(page); + struct zone *uninitialized_var(zone); + bool was_on_lru = false; + bool anon; + + lock_page_cgroup(pc); + if (unlikely(PageCgroupUsed(pc))) { + unlock_page_cgroup(pc); + __mem_cgroup_cancel_charge(memcg, nr_pages); + return; + } + /* + * we don't need page_cgroup_lock about tail pages, becase they are not + * accessed by any other context at this point. + */ + + /* + * 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) { + zone = page_zone(page); + spin_lock_irq(&zone->lru_lock); + if (PageLRU(page)) { + ClearPageLRU(page); + del_page_from_lru_list(zone, page, page_lru(page)); + was_on_lru = true; + } + } + + pc->mem_cgroup = memcg; + /* + * We access a page_cgroup asynchronously without lock_page_cgroup(). + * Especially when a page_cgroup is taken from a page, pc->mem_cgroup + * is accessed after testing USED bit. To make pc->mem_cgroup visible + * before USED bit, we need memory barrier here. + * See mem_cgroup_add_lru_list(), etc. + */ + smp_wmb(); + SetPageCgroupUsed(pc); + + if (lrucare) { + if (was_on_lru) { + VM_BUG_ON(PageLRU(page)); + SetPageLRU(page); + add_page_to_lru_list(zone, page, page_lru(page)); + } + spin_unlock_irq(&zone->lru_lock); + } + + if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED) + anon = true; + else + anon = false; + + mem_cgroup_charge_statistics(memcg, anon, nr_pages); + unlock_page_cgroup(pc); + + /* + * "charge_statistics" updated event counter. Then, check it. + * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree. + * if they exceeds softlimit. + */ + memcg_check_events(memcg, page); +} + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + +#define PCGF_NOCOPY_AT_SPLIT ((1 << PCG_LOCK) | (1 << PCG_MIGRATION)) +/* + * 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) +{ + struct page_cgroup *head_pc = lookup_page_cgroup(head); + struct page_cgroup *pc; + int i; + + if (mem_cgroup_disabled()) + return; + for (i = 1; i < HPAGE_PMD_NR; i++) { + pc = head_pc + i; + pc->mem_cgroup = head_pc->mem_cgroup; + smp_wmb();/* see __commit_charge() */ + pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT; + } +} +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ + +/** + * mem_cgroup_move_account - move account of the page + * @page: the page + * @nr_pages: number of regular pages (>1 for huge pages) + * @pc: page_cgroup of the page. + * @from: mem_cgroup which the page is moved from. + * @to: mem_cgroup which the page is moved to. @from != @to. + * @uncharge: whether we should call uncharge and css_put against @from. + * + * 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" nor css_get to new cgroup. It should be + * done by a caller(__mem_cgroup_try_charge would be useful). If @uncharge is + * true, this function does "uncharge" from old cgroup, but it doesn't if + * @uncharge is false, so a caller should do "uncharge". + */ +static int mem_cgroup_move_account(struct page *page, + unsigned int nr_pages, + struct page_cgroup *pc, + struct mem_cgroup *from, + struct mem_cgroup *to, + bool uncharge) +{ + unsigned long flags; + int ret; + bool anon = PageAnon(page); + + VM_BUG_ON(from == to); + VM_BUG_ON(PageLRU(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; + + lock_page_cgroup(pc); + + ret = -EINVAL; + if (!PageCgroupUsed(pc) || pc->mem_cgroup != from) + goto unlock; + + move_lock_mem_cgroup(from, &flags); + + if (!anon && page_mapped(page)) { + /* Update mapped_file data for mem_cgroup */ + preempt_disable(); + __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); + __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); + preempt_enable(); + } + mem_cgroup_charge_statistics(from, anon, -nr_pages); + if (uncharge) + /* This is not "cancel", but cancel_charge does all we need. */ + __mem_cgroup_cancel_charge(from, nr_pages); + + /* caller should have done css_get */ + pc->mem_cgroup = to; + mem_cgroup_charge_statistics(to, anon, nr_pages); + /* + * We charges against "to" which may not have any tasks. Then, "to" + * can be under rmdir(). But in current implementation, caller of + * this function is just force_empty() and move charge, so it's + * guaranteed that "to" is never removed. So, we don't check rmdir + * status here. + */ + move_unlock_mem_cgroup(from, &flags); + ret = 0; +unlock: + unlock_page_cgroup(pc); + /* + * check events + */ + memcg_check_events(to, page); + memcg_check_events(from, page); +out: + return ret; +} + +/* + * move charges to its parent. + */ + +static int mem_cgroup_move_parent(struct page *page, + struct page_cgroup *pc, + struct mem_cgroup *child, + gfp_t gfp_mask) +{ + struct cgroup *cg = child->css.cgroup; + struct cgroup *pcg = cg->parent; + struct mem_cgroup *parent; + unsigned int nr_pages; + unsigned long uninitialized_var(flags); + int ret; + + /* Is ROOT ? */ + if (!pcg) + return -EINVAL; + + ret = -EBUSY; + if (!get_page_unless_zero(page)) + goto out; + if (isolate_lru_page(page)) + goto put; + + nr_pages = hpage_nr_pages(page); + + parent = mem_cgroup_from_cont(pcg); + ret = __mem_cgroup_try_charge(NULL, gfp_mask, nr_pages, &parent, false); + if (ret) + goto put_back; + + if (nr_pages > 1) + flags = compound_lock_irqsave(page); + + ret = mem_cgroup_move_account(page, nr_pages, pc, child, parent, true); + if (ret) + __mem_cgroup_cancel_charge(parent, nr_pages); + + if (nr_pages > 1) + compound_unlock_irqrestore(page, flags); +put_back: + putback_lru_page(page); +put: + put_page(page); +out: + return ret; +} + +/* + * Charge the memory controller for page usage. + * Return + * 0 if the charge was successful + * < 0 if the cgroup is over its limit + */ +static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, + gfp_t gfp_mask, enum charge_type ctype) +{ + struct mem_cgroup *memcg = NULL; + unsigned int nr_pages = 1; + bool oom = true; + int ret; + + if (PageTransHuge(page)) { + nr_pages <<= compound_order(page); + VM_BUG_ON(!PageTransHuge(page)); + /* + * Never OOM-kill a process for a huge page. The + * fault handler will fall back to regular pages. + */ + oom = false; + } + + ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &memcg, oom); + if (ret == -ENOMEM) + return ret; + __mem_cgroup_commit_charge(memcg, page, nr_pages, ctype, false); + return 0; +} + +int mem_cgroup_newpage_charge(struct page *page, + struct mm_struct *mm, gfp_t gfp_mask) +{ + if (mem_cgroup_disabled()) + return 0; + VM_BUG_ON(page_mapped(page)); + VM_BUG_ON(page->mapping && !PageAnon(page)); + VM_BUG_ON(!mm); + return mem_cgroup_charge_common(page, mm, gfp_mask, + MEM_CGROUP_CHARGE_TYPE_MAPPED); +} + +static void +__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, + enum charge_type ctype); + +int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, + gfp_t gfp_mask) +{ + struct mem_cgroup *memcg = NULL; + enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE; + int ret; + + if (mem_cgroup_disabled()) + return 0; + if (PageCompound(page)) + return 0; + + if (unlikely(!mm)) + mm = &init_mm; + if (!page_is_file_cache(page)) + type = MEM_CGROUP_CHARGE_TYPE_SHMEM; + + if (!PageSwapCache(page)) + ret = mem_cgroup_charge_common(page, mm, gfp_mask, type); + else { /* page is swapcache/shmem */ + ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &memcg); + if (!ret) + __mem_cgroup_commit_charge_swapin(page, memcg, type); + } + return ret; +} + +/* + * While swap-in, try_charge -> commit or cancel, the page is locked. + * And when try_charge() successfully returns, one refcnt to memcg without + * struct page_cgroup is acquired. This refcnt will be consumed by + * "commit()" or removed by "cancel()" + */ +int mem_cgroup_try_charge_swapin(struct mm_struct *mm, + struct page *page, + gfp_t mask, struct mem_cgroup **memcgp) +{ + struct mem_cgroup *memcg; + int ret; + + *memcgp = NULL; + + if (mem_cgroup_disabled()) + return 0; + + if (!do_swap_account) + goto charge_cur_mm; + /* + * A racing thread's fault, or swapoff, may have already updated + * the pte, and even removed page from swap cache: in those cases + * do_swap_page()'s pte_same() test will fail; but there's also a + * KSM case which does need to charge the page. + */ + if (!PageSwapCache(page)) + goto charge_cur_mm; + memcg = try_get_mem_cgroup_from_page(page); + if (!memcg) + goto charge_cur_mm; + *memcgp = memcg; + ret = __mem_cgroup_try_charge(NULL, mask, 1, memcgp, true); + css_put(&memcg->css); + if (ret == -EINTR) + ret = 0; + return ret; +charge_cur_mm: + if (unlikely(!mm)) + mm = &init_mm; + ret = __mem_cgroup_try_charge(mm, mask, 1, memcgp, true); + if (ret == -EINTR) + ret = 0; + return ret; +} + +static void +__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg, + enum charge_type ctype) +{ + if (mem_cgroup_disabled()) + return; + if (!memcg) + return; + cgroup_exclude_rmdir(&memcg->css); + + __mem_cgroup_commit_charge(memcg, page, 1, ctype, true); + /* + * Now swap is on-memory. This means this page may be + * counted both as mem and swap....double count. + * Fix it by uncharging from memsw. Basically, this SwapCache is stable + * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page() + * may call delete_from_swap_cache() before reach here. + */ + if (do_swap_account && PageSwapCache(page)) { + swp_entry_t ent = {.val = page_private(page)}; + struct mem_cgroup *swap_memcg; + unsigned short id; + + id = swap_cgroup_record(ent, 0); + rcu_read_lock(); + swap_memcg = mem_cgroup_lookup(id); + if (swap_memcg) { + /* + * This recorded memcg can be obsolete one. So, avoid + * calling css_tryget + */ + if (!mem_cgroup_is_root(swap_memcg)) + res_counter_uncharge(&swap_memcg->memsw, + PAGE_SIZE); + mem_cgroup_swap_statistics(swap_memcg, false); + mem_cgroup_put(swap_memcg); + } + rcu_read_unlock(); + } + /* + * At swapin, we may charge account against cgroup which has no tasks. + * So, rmdir()->pre_destroy() can be called while we do this charge. + * In that case, we need to call pre_destroy() again. check it here. + */ + cgroup_release_and_wakeup_rmdir(&memcg->css); +} + +void mem_cgroup_commit_charge_swapin(struct page *page, + struct mem_cgroup *memcg) +{ + __mem_cgroup_commit_charge_swapin(page, memcg, + MEM_CGROUP_CHARGE_TYPE_MAPPED); +} + +void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg) +{ + if (mem_cgroup_disabled()) + return; + if (!memcg) + return; + __mem_cgroup_cancel_charge(memcg, 1); +} + +static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg, + unsigned int nr_pages, + const enum charge_type ctype) +{ + struct memcg_batch_info *batch = NULL; + bool uncharge_memsw = true; + + /* If swapout, usage of swap doesn't decrease */ + if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) + uncharge_memsw = false; + + batch = ¤t->memcg_batch; + /* + * In usual, we do css_get() when we remember memcg pointer. + * But in this case, we keep res->usage until end of a series of + * uncharges. Then, it's ok to ignore memcg's refcnt. + */ + if (!batch->memcg) + batch->memcg = memcg; + /* + * do_batch > 0 when unmapping pages or inode invalidate/truncate. + * In those cases, all pages freed continuously can be expected to be in + * the same cgroup and we have chance to coalesce uncharges. + * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE) + * because we want to do uncharge as soon as possible. + */ + + if (!batch->do_batch || test_thread_flag(TIF_MEMDIE)) + goto direct_uncharge; + + if (nr_pages > 1) + goto direct_uncharge; + + /* + * In typical case, batch->memcg == mem. This means we can + * merge a series of uncharges to an uncharge of res_counter. + * If not, we uncharge res_counter ony by one. + */ + if (batch->memcg != memcg) + goto direct_uncharge; + /* remember freed charge and uncharge it later */ + batch->nr_pages++; + if (uncharge_memsw) + batch->memsw_nr_pages++; + return; +direct_uncharge: + res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE); + if (uncharge_memsw) + res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE); + if (unlikely(batch->memcg != memcg)) + memcg_oom_recover(memcg); +} + +/* + * uncharge if !page_mapped(page) + */ +static struct mem_cgroup * +__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype) +{ + struct mem_cgroup *memcg = NULL; + unsigned int nr_pages = 1; + struct page_cgroup *pc; + bool anon; + + if (mem_cgroup_disabled()) + return NULL; + + if (PageSwapCache(page)) + return NULL; + + if (PageTransHuge(page)) { + nr_pages <<= compound_order(page); + VM_BUG_ON(!PageTransHuge(page)); + } + /* + * Check if our page_cgroup is valid + */ + pc = lookup_page_cgroup(page); + if (unlikely(!PageCgroupUsed(pc))) + return NULL; + + lock_page_cgroup(pc); + + memcg = pc->mem_cgroup; + + if (!PageCgroupUsed(pc)) + goto unlock_out; + + anon = PageAnon(page); + + switch (ctype) { + case MEM_CGROUP_CHARGE_TYPE_MAPPED: + /* + * Generally PageAnon tells if it's the anon statistics to be + * updated; but sometimes e.g. mem_cgroup_uncharge_page() is + * used before page reached the stage of being marked PageAnon. + */ + anon = true; + /* fallthrough */ + case MEM_CGROUP_CHARGE_TYPE_DROP: + /* See mem_cgroup_prepare_migration() */ + if (page_mapped(page) || PageCgroupMigration(pc)) + goto unlock_out; + break; + case MEM_CGROUP_CHARGE_TYPE_SWAPOUT: + if (!PageAnon(page)) { /* Shared memory */ + if (page->mapping && !page_is_file_cache(page)) + goto unlock_out; + } else if (page_mapped(page)) /* Anon */ + goto unlock_out; + break; + default: + break; + } + + mem_cgroup_charge_statistics(memcg, anon, -nr_pages); + + ClearPageCgroupUsed(pc); + /* + * pc->mem_cgroup is not cleared here. It will be accessed when it's + * freed from LRU. This is safe because uncharged page is expected not + * to be reused (freed soon). Exception is SwapCache, it's handled by + * special functions. + */ + + unlock_page_cgroup(pc); + /* + * even after unlock, we have memcg->res.usage here and this memcg + * will never be freed. + */ + memcg_check_events(memcg, page); + if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) { + mem_cgroup_swap_statistics(memcg, true); + mem_cgroup_get(memcg); + } + if (!mem_cgroup_is_root(memcg)) + mem_cgroup_do_uncharge(memcg, nr_pages, ctype); + + return memcg; + +unlock_out: + unlock_page_cgroup(pc); + return NULL; +} + +void mem_cgroup_uncharge_page(struct page *page) +{ + /* early check. */ + if (page_mapped(page)) + return; + VM_BUG_ON(page->mapping && !PageAnon(page)); + __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED); +} + +void mem_cgroup_uncharge_cache_page(struct page *page) +{ + VM_BUG_ON(page_mapped(page)); + VM_BUG_ON(page->mapping); + __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE); +} + +/* + * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate. + * In that cases, pages are freed continuously and we can expect pages + * are in the same memcg. All these calls itself limits the number of + * pages freed at once, then uncharge_start/end() is called properly. + * This may be called prural(2) times in a context, + */ + +void mem_cgroup_uncharge_start(void) +{ + current->memcg_batch.do_batch++; + /* We can do nest. */ + if (current->memcg_batch.do_batch == 1) { + current->memcg_batch.memcg = NULL; + current->memcg_batch.nr_pages = 0; + current->memcg_batch.memsw_nr_pages = 0; + } +} + +void mem_cgroup_uncharge_end(void) +{ + struct memcg_batch_info *batch = ¤t->memcg_batch; + + if (!batch->do_batch) + return; + + batch->do_batch--; + if (batch->do_batch) /* If stacked, do nothing. */ + return; + + if (!batch->memcg) + return; + /* + * This "batch->memcg" is valid without any css_get/put etc... + * bacause we hide charges behind us. + */ + if (batch->nr_pages) + res_counter_uncharge(&batch->memcg->res, + batch->nr_pages * PAGE_SIZE); + if (batch->memsw_nr_pages) + res_counter_uncharge(&batch->memcg->memsw, + batch->memsw_nr_pages * PAGE_SIZE); + memcg_oom_recover(batch->memcg); + /* forget this pointer (for sanity check) */ + batch->memcg = NULL; +} + +#ifdef CONFIG_SWAP +/* + * called after __delete_from_swap_cache() and drop "page" account. + * memcg information is recorded to swap_cgroup of "ent" + */ +void +mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) +{ + struct mem_cgroup *memcg; + int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT; + + if (!swapout) /* this was a swap cache but the swap is unused ! */ + ctype = MEM_CGROUP_CHARGE_TYPE_DROP; + + memcg = __mem_cgroup_uncharge_common(page, ctype); + + /* + * record memcg information, if swapout && memcg != NULL, + * mem_cgroup_get() was called in uncharge(). + */ + if (do_swap_account && swapout && memcg) + swap_cgroup_record(ent, css_id(&memcg->css)); +} +#endif + +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP +/* + * called from swap_entry_free(). remove record in swap_cgroup and + * uncharge "memsw" account. + */ +void mem_cgroup_uncharge_swap(swp_entry_t ent) +{ + struct mem_cgroup *memcg; + unsigned short id; + + if (!do_swap_account) + return; + + id = swap_cgroup_record(ent, 0); + rcu_read_lock(); + memcg = mem_cgroup_lookup(id); + if (memcg) { + /* + * We uncharge this because swap is freed. + * This memcg can be obsolete one. We avoid calling css_tryget + */ + if (!mem_cgroup_is_root(memcg)) + res_counter_uncharge(&memcg->memsw, PAGE_SIZE); + mem_cgroup_swap_statistics(memcg, false); + mem_cgroup_put(memcg); + } + rcu_read_unlock(); +} + +/** + * 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 + * @need_fixup: whether we should fixup res_counters and refcounts. + * + * It succeeds only when the swap_cgroup's record for this entry is the same + * as the mem_cgroup's id of @from. + * + * Returns 0 on success, -EINVAL on failure. + * + * The caller must have charged to @to, IOW, called res_counter_charge() about + * both res and memsw, and called css_get(). + */ +static int mem_cgroup_move_swap_account(swp_entry_t entry, + struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup) +{ + unsigned short old_id, new_id; + + old_id = css_id(&from->css); + new_id = css_id(&to->css); + + if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { + mem_cgroup_swap_statistics(from, false); + mem_cgroup_swap_statistics(to, true); + /* + * This function is only called from task migration context now. + * It postpones res_counter and refcount handling till the end + * of task migration(mem_cgroup_clear_mc()) for performance + * improvement. But we cannot postpone mem_cgroup_get(to) + * because if the process that has been moved to @to does + * swap-in, the refcount of @to might be decreased to 0. + */ + mem_cgroup_get(to); + if (need_fixup) { + if (!mem_cgroup_is_root(from)) + res_counter_uncharge(&from->memsw, PAGE_SIZE); + mem_cgroup_put(from); + /* + * we charged both to->res and to->memsw, so we should + * uncharge to->res. + */ + if (!mem_cgroup_is_root(to)) + res_counter_uncharge(&to->res, PAGE_SIZE); + } + 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, bool need_fixup) +{ + return -EINVAL; +} +#endif + +/* + * Before starting migration, account PAGE_SIZE to mem_cgroup that the old + * page belongs to. + */ +int mem_cgroup_prepare_migration(struct page *page, + struct page *newpage, struct mem_cgroup **memcgp, gfp_t gfp_mask) +{ + struct mem_cgroup *memcg = NULL; + struct page_cgroup *pc; + enum charge_type ctype; + int ret = 0; + + *memcgp = NULL; + + VM_BUG_ON(PageTransHuge(page)); + if (mem_cgroup_disabled()) + return 0; + + pc = lookup_page_cgroup(page); + lock_page_cgroup(pc); + if (PageCgroupUsed(pc)) { + memcg = pc->mem_cgroup; + css_get(&memcg->css); + /* + * At migrating an anonymous page, its mapcount goes down + * to 0 and uncharge() will be called. But, even if it's fully + * unmapped, migration may fail and this page has to be + * charged again. We set MIGRATION flag here and delay uncharge + * until end_migration() is called + * + * Corner Case Thinking + * A) + * When the old page was mapped as Anon and it's unmap-and-freed + * while migration was ongoing. + * If unmap finds the old page, uncharge() of it will be delayed + * until end_migration(). If unmap finds a new page, it's + * uncharged when it make mapcount to be 1->0. If unmap code + * finds swap_migration_entry, the new page will not be mapped + * and end_migration() will find it(mapcount==0). + * + * B) + * When the old page was mapped but migraion fails, the kernel + * remaps it. A charge for it is kept by MIGRATION flag even + * if mapcount goes down to 0. We can do remap successfully + * without charging it again. + * + * C) + * The "old" page is under lock_page() until the end of + * migration, so, the old page itself will not be swapped-out. + * If the new page is swapped out before end_migraton, our + * hook to usual swap-out path will catch the event. + */ + if (PageAnon(page)) + SetPageCgroupMigration(pc); + } + unlock_page_cgroup(pc); + /* + * If the page is not charged at this point, + * we return here. + */ + if (!memcg) + return 0; + + *memcgp = memcg; + ret = __mem_cgroup_try_charge(NULL, gfp_mask, 1, memcgp, false); + css_put(&memcg->css);/* drop extra refcnt */ + if (ret) { + if (PageAnon(page)) { + lock_page_cgroup(pc); + ClearPageCgroupMigration(pc); + unlock_page_cgroup(pc); + /* + * The old page may be fully unmapped while we kept it. + */ + mem_cgroup_uncharge_page(page); + } + /* we'll need to revisit this error code (we have -EINTR) */ + return -ENOMEM; + } + /* + * We charge new page before it's used/mapped. So, even if unlock_page() + * is called before end_migration, we can catch all events on this new + * page. In the case new page is migrated but not remapped, new page's + * mapcount will be finally 0 and we call uncharge in end_migration(). + */ + if (PageAnon(page)) + ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED; + else if (page_is_file_cache(page)) + ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; + else + ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM; + __mem_cgroup_commit_charge(memcg, newpage, 1, ctype, false); + return ret; +} + +/* remove redundant charge if migration failed*/ +void mem_cgroup_end_migration(struct mem_cgroup *memcg, + struct page *oldpage, struct page *newpage, bool migration_ok) +{ + struct page *used, *unused; + struct page_cgroup *pc; + bool anon; + + if (!memcg) + return; + /* blocks rmdir() */ + cgroup_exclude_rmdir(&memcg->css); + if (!migration_ok) { + used = oldpage; + unused = newpage; + } else { + used = newpage; + unused = oldpage; + } + /* + * We disallowed uncharge of pages under migration because mapcount + * of the page goes down to zero, temporarly. + * Clear the flag and check the page should be charged. + */ + pc = lookup_page_cgroup(oldpage); + lock_page_cgroup(pc); + ClearPageCgroupMigration(pc); + unlock_page_cgroup(pc); + anon = PageAnon(used); + __mem_cgroup_uncharge_common(unused, + anon ? MEM_CGROUP_CHARGE_TYPE_MAPPED + : MEM_CGROUP_CHARGE_TYPE_CACHE); + + /* + * If a page is a file cache, radix-tree replacement is very atomic + * and we can skip this check. When it was an Anon page, its mapcount + * goes down to 0. But because we added MIGRATION flage, it's not + * uncharged yet. There are several case but page->mapcount check + * and USED bit check in mem_cgroup_uncharge_page() will do enough + * check. (see prepare_charge() also) + */ + if (anon) + mem_cgroup_uncharge_page(used); + /* + * At migration, we may charge account against cgroup which has no + * tasks. + * So, rmdir()->pre_destroy() can be called while we do this charge. + * In that case, we need to call pre_destroy() again. check it here. + */ + cgroup_release_and_wakeup_rmdir(&memcg->css); +} + +/* + * At replace page cache, newpage is not under any memcg but it's on + * LRU. So, this function doesn't touch res_counter but handles LRU + * in correct way. Both pages are locked so we cannot race with uncharge. + */ +void mem_cgroup_replace_page_cache(struct page *oldpage, + struct page *newpage) +{ + struct mem_cgroup *memcg; + struct page_cgroup *pc; + enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE; + + if (mem_cgroup_disabled()) + return; + + pc = lookup_page_cgroup(oldpage); + /* fix accounting on old pages */ + lock_page_cgroup(pc); + memcg = pc->mem_cgroup; + mem_cgroup_charge_statistics(memcg, false, -1); + ClearPageCgroupUsed(pc); + unlock_page_cgroup(pc); + + if (PageSwapBacked(oldpage)) + type = MEM_CGROUP_CHARGE_TYPE_SHMEM; + + /* + * Even if newpage->mapping was NULL before starting replacement, + * the newpage may be on LRU(or pagevec for LRU) already. We lock + * LRU while we overwrite pc->mem_cgroup. + */ + __mem_cgroup_commit_charge(memcg, newpage, 1, type, true); +} + +#ifdef CONFIG_DEBUG_VM +static struct page_cgroup *lookup_page_cgroup_used(struct page *page) +{ + struct page_cgroup *pc; + + pc = lookup_page_cgroup(page); + /* + * Can be NULL while feeding pages into the page allocator for + * the first time, i.e. during boot or memory hotplug; + * or when mem_cgroup_disabled(). + */ + if (likely(pc) && PageCgroupUsed(pc)) + return pc; + return NULL; +} + +bool mem_cgroup_bad_page_check(struct page *page) +{ + if (mem_cgroup_disabled()) + return false; + + return lookup_page_cgroup_used(page) != NULL; +} + +void mem_cgroup_print_bad_page(struct page *page) +{ + struct page_cgroup *pc; + + pc = lookup_page_cgroup_used(page); + if (pc) { + printk(KERN_ALERT "pc:%p pc->flags:%lx pc->mem_cgroup:%p\n", + pc, pc->flags, pc->mem_cgroup); + } +} +#endif + +static DEFINE_MUTEX(set_limit_mutex); + +static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, + unsigned long long val) +{ + int retry_count; + u64 memswlimit, memlimit; + int ret = 0; + int children = mem_cgroup_count_children(memcg); + u64 curusage, oldusage; + int enlarge; + + /* + * For keeping hierarchical_reclaim simple, how long we should retry + * is depends on callers. We set our retry-count to be function + * of # of children which we should visit in this loop. + */ + retry_count = MEM_CGROUP_RECLAIM_RETRIES * children; + + oldusage = res_counter_read_u64(&memcg->res, RES_USAGE); + + enlarge = 0; + while (retry_count) { + if (signal_pending(current)) { + ret = -EINTR; + break; + } + /* + * Rather than hide all in some function, I do this in + * open coded manner. You see what this really does. + * We have to guarantee memcg->res.limit < memcg->memsw.limit. + */ + mutex_lock(&set_limit_mutex); + memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); + if (memswlimit < val) { + ret = -EINVAL; + mutex_unlock(&set_limit_mutex); + break; + } + + memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); + if (memlimit < val) + enlarge = 1; + + ret = res_counter_set_limit(&memcg->res, val); + if (!ret) { + if (memswlimit == val) + memcg->memsw_is_minimum = true; + else + memcg->memsw_is_minimum = false; + } + mutex_unlock(&set_limit_mutex); + + if (!ret) + break; + + mem_cgroup_reclaim(memcg, GFP_KERNEL, + MEM_CGROUP_RECLAIM_SHRINK); + curusage = res_counter_read_u64(&memcg->res, RES_USAGE); + /* Usage is reduced ? */ + if (curusage >= oldusage) + retry_count--; + else + oldusage = curusage; + } + if (!ret && enlarge) + memcg_oom_recover(memcg); + + return ret; +} + +static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, + unsigned long long val) +{ + int retry_count; + u64 memlimit, memswlimit, oldusage, curusage; + int children = mem_cgroup_count_children(memcg); + int ret = -EBUSY; + int enlarge = 0; + + /* see mem_cgroup_resize_res_limit */ + retry_count = children * MEM_CGROUP_RECLAIM_RETRIES; + oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); + while (retry_count) { + if (signal_pending(current)) { + ret = -EINTR; + break; + } + /* + * Rather than hide all in some function, I do this in + * open coded manner. You see what this really does. + * We have to guarantee memcg->res.limit < memcg->memsw.limit. + */ + mutex_lock(&set_limit_mutex); + memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); + if (memlimit > val) { + ret = -EINVAL; + mutex_unlock(&set_limit_mutex); + break; + } + memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); + if (memswlimit < val) + enlarge = 1; + ret = res_counter_set_limit(&memcg->memsw, val); + if (!ret) { + if (memlimit == val) + memcg->memsw_is_minimum = true; + else + memcg->memsw_is_minimum = false; + } + mutex_unlock(&set_limit_mutex); + + if (!ret) + break; + + mem_cgroup_reclaim(memcg, GFP_KERNEL, + MEM_CGROUP_RECLAIM_NOSWAP | + MEM_CGROUP_RECLAIM_SHRINK); + curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); + /* Usage is reduced ? */ + if (curusage >= oldusage) + retry_count--; + else + oldusage = curusage; + } + 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 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(&mctz->lock); + + /* + * If we failed to reclaim anything from this memory cgroup + * it is time to move on to the next cgroup + */ + next_mz = NULL; + if (!reclaimed) { + do { + /* + * Loop until we find yet another one. + * + * By the time we get the soft_limit lock + * again, someone might have aded the + * group back on the RB tree. Iterate to + * make sure we get a different mem. + * mem_cgroup_largest_soft_limit_node returns + * NULL if no other cgroup is present on + * the tree + */ + next_mz = + __mem_cgroup_largest_soft_limit_node(mctz); + if (next_mz == mz) + css_put(&next_mz->memcg->css); + else /* next_mz == NULL or other memcg */ + break; + } while (1); + } + __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz); + excess = res_counter_soft_limit_excess(&mz->memcg->res); + /* + * 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->memcg, mz, mctz, excess); + spin_unlock(&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; +} + +/* + * This routine traverse page_cgroup in given list and drop them all. + * *And* this routine doesn't reclaim page itself, just removes page_cgroup. + */ +static int mem_cgroup_force_empty_list(struct mem_cgroup *memcg, + int node, int zid, enum lru_list lru) +{ + struct mem_cgroup_per_zone *mz; + unsigned long flags, loop; + struct list_head *list; + struct page *busy; + struct zone *zone; + int ret = 0; + + zone = &NODE_DATA(node)->node_zones[zid]; + mz = mem_cgroup_zoneinfo(memcg, node, zid); + list = &mz->lruvec.lists[lru]; + + loop = mz->lru_size[lru]; + /* give some margin against EBUSY etc...*/ + loop += 256; + busy = NULL; + while (loop--) { + struct page_cgroup *pc; + struct page *page; + + ret = 0; + spin_lock_irqsave(&zone->lru_lock, flags); + if (list_empty(list)) { + spin_unlock_irqrestore(&zone->lru_lock, flags); + break; + } + page = list_entry(list->prev, struct page, lru); + if (busy == page) { + list_move(&page->lru, list); + busy = NULL; + spin_unlock_irqrestore(&zone->lru_lock, flags); + continue; + } + spin_unlock_irqrestore(&zone->lru_lock, flags); + + pc = lookup_page_cgroup(page); + + ret = mem_cgroup_move_parent(page, pc, memcg, GFP_KERNEL); + if (ret == -ENOMEM || ret == -EINTR) + break; + + if (ret == -EBUSY || ret == -EINVAL) { + /* found lock contention or "pc" is obsolete. */ + busy = page; + cond_resched(); + } else + busy = NULL; + } + + if (!ret && !list_empty(list)) + return -EBUSY; + return ret; +} + +/* + * make mem_cgroup's charge to be 0 if there is no task. + * This enables deleting this mem_cgroup. + */ +static int mem_cgroup_force_empty(struct mem_cgroup *memcg, bool free_all) +{ + int ret; + int node, zid, shrink; + int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; + struct cgroup *cgrp = memcg->css.cgroup; + + css_get(&memcg->css); + + shrink = 0; + /* should free all ? */ + if (free_all) + goto try_to_free; +move_account: + do { + ret = -EBUSY; + if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children)) + goto out; + ret = -EINTR; + if (signal_pending(current)) + goto out; + /* This is for making all *used* pages to be on LRU. */ + lru_add_drain_all(); + drain_all_stock_sync(memcg); + ret = 0; + mem_cgroup_start_move(memcg); + for_each_node_state(node, N_HIGH_MEMORY) { + for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) { + enum lru_list lru; + for_each_lru(lru) { + ret = mem_cgroup_force_empty_list(memcg, + node, zid, lru); + if (ret) + break; + } + } + if (ret) + break; + } + mem_cgroup_end_move(memcg); + memcg_oom_recover(memcg); + /* it seems parent cgroup doesn't have enough mem */ + if (ret == -ENOMEM) + goto try_to_free; + cond_resched(); + /* "ret" should also be checked to ensure all lists are empty. */ + } while (res_counter_read_u64(&memcg->res, RES_USAGE) > 0 || ret); +out: + css_put(&memcg->css); + return ret; + +try_to_free: + /* returns EBUSY if there is a task or if we come here twice. */ + if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) { + ret = -EBUSY; + goto out; + } + /* we call try-to-free pages for make this cgroup empty */ + lru_add_drain_all(); + /* try to free all pages in this cgroup */ + shrink = 1; + while (nr_retries && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) { + int progress; + + if (signal_pending(current)) { + ret = -EINTR; + goto out; + } + progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL, + false); + if (!progress) { + nr_retries--; + /* maybe some writeback is necessary */ + congestion_wait(BLK_RW_ASYNC, HZ/10); + } + + } + lru_add_drain(); + /* try move_account...there may be some *locked* pages. */ + goto move_account; +} + +int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event) +{ + return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true); +} + + +static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft) +{ + return mem_cgroup_from_cont(cont)->use_hierarchy; +} + +static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft, + u64 val) +{ + int retval = 0; + struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + struct cgroup *parent = cont->parent; + struct mem_cgroup *parent_memcg = NULL; + + if (parent) + parent_memcg = mem_cgroup_from_cont(parent); + + cgroup_lock(); + /* + * 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 (list_empty(&cont->children)) + memcg->use_hierarchy = val; + else + retval = -EBUSY; + } else + retval = -EINVAL; + cgroup_unlock(); + + return retval; +} + + +static unsigned long mem_cgroup_recursive_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)) { + if (!swap) + return res_counter_read_u64(&memcg->res, RES_USAGE); + else + return res_counter_read_u64(&memcg->memsw, RES_USAGE); + } + + val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE); + val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS); + + if (swap) + val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAPOUT); + + return val << PAGE_SHIFT; +} + +static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + u64 val; + int type, name; + + type = MEMFILE_TYPE(cft->private); + name = MEMFILE_ATTR(cft->private); + switch (type) { + case _MEM: + if (name == RES_USAGE) + val = mem_cgroup_usage(memcg, false); + else + val = res_counter_read_u64(&memcg->res, name); + break; + case _MEMSWAP: + if (name == RES_USAGE) + val = mem_cgroup_usage(memcg, true); + else + val = res_counter_read_u64(&memcg->memsw, name); + break; + default: + BUG(); + } + return val; +} +/* + * The user of this function is... + * RES_LIMIT. + */ +static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft, + const char *buffer) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + int type, name; + unsigned long long val; + int ret; + + type = MEMFILE_TYPE(cft->private); + name = MEMFILE_ATTR(cft->private); + switch (name) { + case RES_LIMIT: + if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */ + ret = -EINVAL; + break; + } + /* This function does all necessary parse...reuse it */ + ret = res_counter_memparse_write_strategy(buffer, &val); + if (ret) + break; + if (type == _MEM) + ret = mem_cgroup_resize_limit(memcg, val); + else + ret = mem_cgroup_resize_memsw_limit(memcg, val); + break; + case RES_SOFT_LIMIT: + ret = res_counter_memparse_write_strategy(buffer, &val); + if (ret) + break; + /* + * For memsw, soft limits are hard to implement in terms + * of semantics, for now, we support soft limits for + * control without swap + */ + if (type == _MEM) + ret = res_counter_set_soft_limit(&memcg->res, val); + else + ret = -EINVAL; + break; + default: + ret = -EINVAL; /* should be BUG() ? */ + break; + } + return ret; +} + +static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg, + unsigned long long *mem_limit, unsigned long long *memsw_limit) +{ + struct cgroup *cgroup; + unsigned long long min_limit, min_memsw_limit, tmp; + + min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT); + min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); + cgroup = memcg->css.cgroup; + if (!memcg->use_hierarchy) + goto out; + + while (cgroup->parent) { + cgroup = cgroup->parent; + memcg = mem_cgroup_from_cont(cgroup); + if (!memcg->use_hierarchy) + break; + tmp = res_counter_read_u64(&memcg->res, RES_LIMIT); + min_limit = min(min_limit, tmp); + tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT); + min_memsw_limit = min(min_memsw_limit, tmp); + } +out: + *mem_limit = min_limit; + *memsw_limit = min_memsw_limit; +} + +static int mem_cgroup_reset(struct cgroup *cont, unsigned int event) +{ + struct mem_cgroup *memcg; + int type, name; + + memcg = mem_cgroup_from_cont(cont); + type = MEMFILE_TYPE(event); + name = MEMFILE_ATTR(event); + switch (name) { + case RES_MAX_USAGE: + if (type == _MEM) + res_counter_reset_max(&memcg->res); + else + res_counter_reset_max(&memcg->memsw); + break; + case RES_FAILCNT: + if (type == _MEM) + res_counter_reset_failcnt(&memcg->res); + else + res_counter_reset_failcnt(&memcg->memsw); + break; + } + + return 0; +} + +static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp, + struct cftype *cft) +{ + return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate; +} + +#ifdef CONFIG_MMU +static int mem_cgroup_move_charge_write(struct cgroup *cgrp, + struct cftype *cft, u64 val) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + + if (val >= (1 << NR_MOVE_TYPE)) + return -EINVAL; + /* + * We check this value several times in both in can_attach() and + * attach(), so we need cgroup lock to prevent this value from being + * inconsistent. + */ + cgroup_lock(); + memcg->move_charge_at_immigrate = val; + cgroup_unlock(); + + return 0; +} +#else +static int mem_cgroup_move_charge_write(struct cgroup *cgrp, + struct cftype *cft, u64 val) +{ + return -ENOSYS; +} +#endif + + +/* For read statistics */ +enum { + MCS_CACHE, + MCS_RSS, + MCS_FILE_MAPPED, + MCS_PGPGIN, + MCS_PGPGOUT, + MCS_SWAP, + MCS_PGFAULT, + MCS_PGMAJFAULT, + MCS_INACTIVE_ANON, + MCS_ACTIVE_ANON, + MCS_INACTIVE_FILE, + MCS_ACTIVE_FILE, + MCS_UNEVICTABLE, + NR_MCS_STAT, +}; + +struct mcs_total_stat { + s64 stat[NR_MCS_STAT]; +}; + +struct { + char *local_name; + char *total_name; +} memcg_stat_strings[NR_MCS_STAT] = { + {"cache", "total_cache"}, + {"rss", "total_rss"}, + {"mapped_file", "total_mapped_file"}, + {"pgpgin", "total_pgpgin"}, + {"pgpgout", "total_pgpgout"}, + {"swap", "total_swap"}, + {"pgfault", "total_pgfault"}, + {"pgmajfault", "total_pgmajfault"}, + {"inactive_anon", "total_inactive_anon"}, + {"active_anon", "total_active_anon"}, + {"inactive_file", "total_inactive_file"}, + {"active_file", "total_active_file"}, + {"unevictable", "total_unevictable"} +}; + + +static void +mem_cgroup_get_local_stat(struct mem_cgroup *memcg, struct mcs_total_stat *s) +{ + s64 val; + + /* per cpu stat */ + val = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_CACHE); + s->stat[MCS_CACHE] += val * PAGE_SIZE; + val = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_RSS); + s->stat[MCS_RSS] += val * PAGE_SIZE; + val = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_FILE_MAPPED); + s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE; + val = mem_cgroup_read_events(memcg, MEM_CGROUP_EVENTS_PGPGIN); + s->stat[MCS_PGPGIN] += val; + val = mem_cgroup_read_events(memcg, MEM_CGROUP_EVENTS_PGPGOUT); + s->stat[MCS_PGPGOUT] += val; + if (do_swap_account) { + val = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_SWAPOUT); + s->stat[MCS_SWAP] += val * PAGE_SIZE; + } + val = mem_cgroup_read_events(memcg, MEM_CGROUP_EVENTS_PGFAULT); + s->stat[MCS_PGFAULT] += val; + val = mem_cgroup_read_events(memcg, MEM_CGROUP_EVENTS_PGMAJFAULT); + s->stat[MCS_PGMAJFAULT] += val; + + /* per zone stat */ + val = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_INACTIVE_ANON)); + s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE; + val = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_ACTIVE_ANON)); + s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE; + val = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_INACTIVE_FILE)); + s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE; + val = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_ACTIVE_FILE)); + s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE; + val = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_UNEVICTABLE)); + s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE; +} + +static void +mem_cgroup_get_total_stat(struct mem_cgroup *memcg, struct mcs_total_stat *s) +{ + struct mem_cgroup *iter; + + for_each_mem_cgroup_tree(iter, memcg) + mem_cgroup_get_local_stat(iter, s); +} + +#ifdef CONFIG_NUMA +static int mem_control_numa_stat_show(struct seq_file *m, void *arg) +{ + int nid; + unsigned long total_nr, file_nr, anon_nr, unevictable_nr; + unsigned long node_nr; + struct cgroup *cont = m->private; + struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + + total_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL); + seq_printf(m, "total=%lu", total_nr); + for_each_node_state(nid, N_HIGH_MEMORY) { + node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL); + seq_printf(m, " N%d=%lu", nid, node_nr); + } + seq_putc(m, '\n'); + + file_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL_FILE); + seq_printf(m, "file=%lu", file_nr); + for_each_node_state(nid, N_HIGH_MEMORY) { + node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, + LRU_ALL_FILE); + seq_printf(m, " N%d=%lu", nid, node_nr); + } + seq_putc(m, '\n'); + + anon_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL_ANON); + seq_printf(m, "anon=%lu", anon_nr); + for_each_node_state(nid, N_HIGH_MEMORY) { + node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, + LRU_ALL_ANON); + seq_printf(m, " N%d=%lu", nid, node_nr); + } + seq_putc(m, '\n'); + + unevictable_nr = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_UNEVICTABLE)); + seq_printf(m, "unevictable=%lu", unevictable_nr); + for_each_node_state(nid, N_HIGH_MEMORY) { + node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, + BIT(LRU_UNEVICTABLE)); + seq_printf(m, " N%d=%lu", nid, node_nr); + } + seq_putc(m, '\n'); + return 0; +} +#endif /* CONFIG_NUMA */ + +static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft, + struct cgroup_map_cb *cb) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + struct mcs_total_stat mystat; + int i; + + memset(&mystat, 0, sizeof(mystat)); + mem_cgroup_get_local_stat(memcg, &mystat); + + + for (i = 0; i < NR_MCS_STAT; i++) { + if (i == MCS_SWAP && !do_swap_account) + continue; + cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]); + } + + /* Hierarchical information */ + { + unsigned long long limit, memsw_limit; + memcg_get_hierarchical_limit(memcg, &limit, &memsw_limit); + cb->fill(cb, "hierarchical_memory_limit", limit); + if (do_swap_account) + cb->fill(cb, "hierarchical_memsw_limit", memsw_limit); + } + + memset(&mystat, 0, sizeof(mystat)); + mem_cgroup_get_total_stat(memcg, &mystat); + for (i = 0; i < NR_MCS_STAT; i++) { + if (i == MCS_SWAP && !do_swap_account) + continue; + cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]); + } + +#ifdef CONFIG_DEBUG_VM + { + int nid, zid; + struct mem_cgroup_per_zone *mz; + unsigned long recent_rotated[2] = {0, 0}; + unsigned long recent_scanned[2] = {0, 0}; + + for_each_online_node(nid) + for (zid = 0; zid < MAX_NR_ZONES; zid++) { + mz = mem_cgroup_zoneinfo(memcg, nid, zid); + + recent_rotated[0] += + mz->reclaim_stat.recent_rotated[0]; + recent_rotated[1] += + mz->reclaim_stat.recent_rotated[1]; + recent_scanned[0] += + mz->reclaim_stat.recent_scanned[0]; + recent_scanned[1] += + mz->reclaim_stat.recent_scanned[1]; + } + cb->fill(cb, "recent_rotated_anon", recent_rotated[0]); + cb->fill(cb, "recent_rotated_file", recent_rotated[1]); + cb->fill(cb, "recent_scanned_anon", recent_scanned[0]); + cb->fill(cb, "recent_scanned_file", recent_scanned[1]); + } +#endif + + return 0; +} + +static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + + return mem_cgroup_swappiness(memcg); +} + +static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft, + u64 val) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + struct mem_cgroup *parent; + + if (val > 100) + return -EINVAL; + + if (cgrp->parent == NULL) + return -EINVAL; + + parent = mem_cgroup_from_cont(cgrp->parent); + + cgroup_lock(); + + /* If under hierarchy, only empty-root can set this value */ + if ((parent->use_hierarchy) || + (memcg->use_hierarchy && !list_empty(&cgrp->children))) { + cgroup_unlock(); + return -EINVAL; + } + + memcg->swappiness = val; + + cgroup_unlock(); + + return 0; +} + +static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap) +{ + struct mem_cgroup_threshold_ary *t; + u64 usage; + int i; + + rcu_read_lock(); + if (!swap) + 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 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; + + return _a->threshold - _b->threshold; +} + +static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg) +{ + struct mem_cgroup_eventfd_list *ev; + + list_for_each_entry(ev, &memcg->oom_notify, list) + eventfd_signal(ev->eventfd, 1); + 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 cgroup *cgrp, + struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + struct mem_cgroup_thresholds *thresholds; + struct mem_cgroup_threshold_ary *new; + int type = MEMFILE_TYPE(cft->private); + u64 threshold, usage; + int i, size, ret; + + ret = res_counter_memparse_write_strategy(args, &threshold); + if (ret) + return ret; + + mutex_lock(&memcg->thresholds_lock); + + if (type == _MEM) + thresholds = &memcg->thresholds; + else if (type == _MEMSWAP) + thresholds = &memcg->memsw_thresholds; + else + BUG(); + + usage = mem_cgroup_usage(memcg, type == _MEMSWAP); + + /* 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; + } + } + + /* 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 void mem_cgroup_usage_unregister_event(struct cgroup *cgrp, + struct cftype *cft, struct eventfd_ctx *eventfd) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + struct mem_cgroup_thresholds *thresholds; + struct mem_cgroup_threshold_ary *new; + int type = MEMFILE_TYPE(cft->private); + u64 usage; + int i, j, size; + + mutex_lock(&memcg->thresholds_lock); + if (type == _MEM) + thresholds = &memcg->thresholds; + else if (type == _MEMSWAP) + thresholds = &memcg->memsw_thresholds; + else + BUG(); + + if (!thresholds->primary) + goto unlock; + + usage = mem_cgroup_usage(memcg, type == _MEMSWAP); + + /* Check if a threshold crossed before removing */ + __mem_cgroup_threshold(memcg, type == _MEMSWAP); + + /* Calculate new number of threshold */ + 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 int mem_cgroup_oom_register_event(struct cgroup *cgrp, + struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + struct mem_cgroup_eventfd_list *event; + int type = MEMFILE_TYPE(cft->private); + + BUG_ON(type != _OOM_TYPE); + event = kmalloc(sizeof(*event), GFP_KERNEL); + if (!event) + return -ENOMEM; + + 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 cgroup *cgrp, + struct cftype *cft, struct eventfd_ctx *eventfd) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + struct mem_cgroup_eventfd_list *ev, *tmp; + int type = MEMFILE_TYPE(cft->private); + + BUG_ON(type != _OOM_TYPE); + + 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 cgroup *cgrp, + struct cftype *cft, struct cgroup_map_cb *cb) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + + cb->fill(cb, "oom_kill_disable", memcg->oom_kill_disable); + + if (atomic_read(&memcg->under_oom)) + cb->fill(cb, "under_oom", 1); + else + cb->fill(cb, "under_oom", 0); + return 0; +} + +static int mem_cgroup_oom_control_write(struct cgroup *cgrp, + struct cftype *cft, u64 val) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + struct mem_cgroup *parent; + + /* cannot set to root cgroup and only 0 and 1 are allowed */ + if (!cgrp->parent || !((val == 0) || (val == 1))) + return -EINVAL; + + parent = mem_cgroup_from_cont(cgrp->parent); + + cgroup_lock(); + /* oom-kill-disable is a flag for subhierarchy. */ + if ((parent->use_hierarchy) || + (memcg->use_hierarchy && !list_empty(&cgrp->children))) { + cgroup_unlock(); + return -EINVAL; + } + memcg->oom_kill_disable = val; + if (!val) + memcg_oom_recover(memcg); + cgroup_unlock(); + return 0; +} + +#ifdef CONFIG_NUMA +static const struct file_operations mem_control_numa_stat_file_operations = { + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static int mem_control_numa_stat_open(struct inode *unused, struct file *file) +{ + struct cgroup *cont = file->f_dentry->d_parent->d_fsdata; + + file->f_op = &mem_control_numa_stat_file_operations; + return single_open(file, mem_control_numa_stat_show, cont); +} +#endif /* CONFIG_NUMA */ + +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM +static int register_kmem_files(struct cgroup *cont, struct cgroup_subsys *ss) +{ + /* + * Part of this would be better living in a separate allocation + * function, leaving us with just the cgroup tree population work. + * We, however, depend on state such as network's proto_list that + * is only initialized after cgroup creation. I found the less + * cumbersome way to deal with it to defer it all to populate time + */ + return mem_cgroup_sockets_init(cont, ss); +}; + +static void kmem_cgroup_destroy(struct cgroup *cont) +{ + mem_cgroup_sockets_destroy(cont); +} +#else +static int register_kmem_files(struct cgroup *cont, struct cgroup_subsys *ss) +{ + return 0; +} + +static void kmem_cgroup_destroy(struct cgroup *cont) +{ +} +#endif + +static struct cftype mem_cgroup_files[] = { + { + .name = "usage_in_bytes", + .private = MEMFILE_PRIVATE(_MEM, RES_USAGE), + .read_u64 = mem_cgroup_read, + .register_event = mem_cgroup_usage_register_event, + .unregister_event = mem_cgroup_usage_unregister_event, + }, + { + .name = "max_usage_in_bytes", + .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE), + .trigger = mem_cgroup_reset, + .read_u64 = mem_cgroup_read, + }, + { + .name = "limit_in_bytes", + .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT), + .write_string = mem_cgroup_write, + .read_u64 = mem_cgroup_read, + }, + { + .name = "soft_limit_in_bytes", + .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT), + .write_string = mem_cgroup_write, + .read_u64 = mem_cgroup_read, + }, + { + .name = "failcnt", + .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT), + .trigger = mem_cgroup_reset, + .read_u64 = mem_cgroup_read, + }, + { + .name = "stat", + .read_map = mem_control_stat_show, + }, + { + .name = "force_empty", + .trigger = mem_cgroup_force_empty_write, + }, + { + .name = "use_hierarchy", + .write_u64 = mem_cgroup_hierarchy_write, + .read_u64 = mem_cgroup_hierarchy_read, + }, + { + .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", + .read_map = mem_cgroup_oom_control_read, + .write_u64 = mem_cgroup_oom_control_write, + .register_event = mem_cgroup_oom_register_event, + .unregister_event = mem_cgroup_oom_unregister_event, + .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL), + }, +#ifdef CONFIG_NUMA + { + .name = "numa_stat", + .open = mem_control_numa_stat_open, + .mode = S_IRUGO, + }, +#endif +}; + +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP +static struct cftype memsw_cgroup_files[] = { + { + .name = "memsw.usage_in_bytes", + .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), + .read_u64 = mem_cgroup_read, + .register_event = mem_cgroup_usage_register_event, + .unregister_event = mem_cgroup_usage_unregister_event, + }, + { + .name = "memsw.max_usage_in_bytes", + .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE), + .trigger = mem_cgroup_reset, + .read_u64 = mem_cgroup_read, + }, + { + .name = "memsw.limit_in_bytes", + .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT), + .write_string = mem_cgroup_write, + .read_u64 = mem_cgroup_read, + }, + { + .name = "memsw.failcnt", + .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT), + .trigger = mem_cgroup_reset, + .read_u64 = mem_cgroup_read, + }, +}; + +static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) +{ + if (!do_swap_account) + return 0; + return cgroup_add_files(cont, ss, memsw_cgroup_files, + ARRAY_SIZE(memsw_cgroup_files)); +}; +#else +static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) +{ + return 0; +} +#endif + +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; + enum lru_list lru; + 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]; + for_each_lru(lru) + INIT_LIST_HEAD(&mz->lruvec.lists[lru]); + mz->usage_in_excess = 0; + mz->on_tree = false; + mz->memcg = memcg; + } + memcg->info.nodeinfo[node] = pn; + return 0; +} + +static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node) +{ + kfree(memcg->info.nodeinfo[node]); +} + +static struct mem_cgroup *mem_cgroup_alloc(void) +{ + struct mem_cgroup *memcg; + int size = sizeof(struct mem_cgroup); + + /* Can be very big if MAX_NUMNODES is very big */ + if (size < PAGE_SIZE) + memcg = kzalloc(size, GFP_KERNEL); + else + memcg = vzalloc(size); + + 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: + if (size < PAGE_SIZE) + kfree(memcg); + else + vfree(memcg); + return NULL; +} + +/* + * Helpers for freeing a vzalloc()ed mem_cgroup by RCU, + * but in process context. The work_freeing structure is overlaid + * on the rcu_freeing structure, which itself is overlaid on memsw. + */ +static void vfree_work(struct work_struct *work) +{ + struct mem_cgroup *memcg; + + memcg = container_of(work, struct mem_cgroup, work_freeing); + vfree(memcg); +} +static void vfree_rcu(struct rcu_head *rcu_head) +{ + struct mem_cgroup *memcg; + + memcg = container_of(rcu_head, struct mem_cgroup, rcu_freeing); + INIT_WORK(&memcg->work_freeing, vfree_work); + schedule_work(&memcg->work_freeing); +} + +/* + * 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); + free_css_id(&mem_cgroup_subsys, &memcg->css); + + for_each_node(node) + free_mem_cgroup_per_zone_info(memcg, node); + + free_percpu(memcg->stat); + if (sizeof(struct mem_cgroup) < PAGE_SIZE) + kfree_rcu(memcg, rcu_freeing); + else + call_rcu(&memcg->rcu_freeing, vfree_rcu); +} + +static void mem_cgroup_get(struct mem_cgroup *memcg) +{ + atomic_inc(&memcg->refcnt); +} + +static void __mem_cgroup_put(struct mem_cgroup *memcg, int count) +{ + if (atomic_sub_and_test(count, &memcg->refcnt)) { + struct mem_cgroup *parent = parent_mem_cgroup(memcg); + __mem_cgroup_free(memcg); + if (parent) + mem_cgroup_put(parent); + } +} + +static void mem_cgroup_put(struct mem_cgroup *memcg) +{ + __mem_cgroup_put(memcg, 1); +} + +/* + * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled. + */ +struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg) +{ + if (!memcg->res.parent) + return NULL; + return mem_cgroup_from_res_counter(memcg->res.parent, res); +} +EXPORT_SYMBOL(parent_mem_cgroup); + +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP +static void __init enable_swap_cgroup(void) +{ + if (!mem_cgroup_disabled() && really_do_swap_account) + do_swap_account = 1; +} +#else +static void __init enable_swap_cgroup(void) +{ +} +#endif + +static int mem_cgroup_soft_limit_tree_init(void) +{ + struct mem_cgroup_tree_per_node *rtpn; + struct mem_cgroup_tree_per_zone *rtpz; + int tmp, node, zone; + + for_each_node(node) { + tmp = node; + if (!node_state(node, N_NORMAL_MEMORY)) + tmp = -1; + rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp); + if (!rtpn) + goto err_cleanup; + + soft_limit_tree.rb_tree_per_node[node] = rtpn; + + for (zone = 0; zone < MAX_NR_ZONES; zone++) { + rtpz = &rtpn->rb_tree_per_zone[zone]; + rtpz->rb_root = RB_ROOT; + spin_lock_init(&rtpz->lock); + } + } + return 0; + +err_cleanup: + for_each_node(node) { + if (!soft_limit_tree.rb_tree_per_node[node]) + break; + kfree(soft_limit_tree.rb_tree_per_node[node]); + soft_limit_tree.rb_tree_per_node[node] = NULL; + } + return 1; + +} + +static struct cgroup_subsys_state * __ref +mem_cgroup_create(struct cgroup *cont) +{ + struct mem_cgroup *memcg, *parent; + 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 (cont->parent == NULL) { + int cpu; + enable_swap_cgroup(); + parent = NULL; + if (mem_cgroup_soft_limit_tree_init()) + goto free_out; + root_mem_cgroup = memcg; + for_each_possible_cpu(cpu) { + struct memcg_stock_pcp *stock = + &per_cpu(memcg_stock, cpu); + INIT_WORK(&stock->work, drain_local_stock); + } + hotcpu_notifier(memcg_cpu_hotplug_callback, 0); + } else { + parent = mem_cgroup_from_cont(cont->parent); + memcg->use_hierarchy = parent->use_hierarchy; + memcg->oom_kill_disable = parent->oom_kill_disable; + } + + if (parent && parent->use_hierarchy) { + res_counter_init(&memcg->res, &parent->res); + res_counter_init(&memcg->memsw, &parent->memsw); + /* + * We increment refcnt of the parent to ensure that we can + * safely access it on res_counter_charge/uncharge. + * This refcnt will be decremented when freeing this + * mem_cgroup(see mem_cgroup_put). + */ + mem_cgroup_get(parent); + } else { + res_counter_init(&memcg->res, NULL); + res_counter_init(&memcg->memsw, NULL); + } + memcg->last_scanned_node = MAX_NUMNODES; + INIT_LIST_HEAD(&memcg->oom_notify); + + if (parent) + memcg->swappiness = mem_cgroup_swappiness(parent); + atomic_set(&memcg->refcnt, 1); + memcg->move_charge_at_immigrate = 0; + mutex_init(&memcg->thresholds_lock); + spin_lock_init(&memcg->move_lock); + return &memcg->css; +free_out: + __mem_cgroup_free(memcg); + return ERR_PTR(error); +} + +static int mem_cgroup_pre_destroy(struct cgroup *cont) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + + return mem_cgroup_force_empty(memcg, false); +} + +static void mem_cgroup_destroy(struct cgroup *cont) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + + kmem_cgroup_destroy(cont); + + mem_cgroup_put(memcg); +} + +static int mem_cgroup_populate(struct cgroup_subsys *ss, + struct cgroup *cont) +{ + int ret; + + ret = cgroup_add_files(cont, ss, mem_cgroup_files, + ARRAY_SIZE(mem_cgroup_files)); + + if (!ret) + ret = register_memsw_files(cont, ss); + + if (!ret) + ret = register_kmem_files(cont, ss); + + return ret; +} + +#ifdef CONFIG_MMU +/* Handlers for move charge at task migration. */ +#define PRECHARGE_COUNT_AT_ONCE 256 +static int mem_cgroup_do_precharge(unsigned long count) +{ + int ret = 0; + int batch_count = PRECHARGE_COUNT_AT_ONCE; + struct mem_cgroup *memcg = mc.to; + + if (mem_cgroup_is_root(memcg)) { + mc.precharge += count; + /* we don't need css_get for root */ + return ret; + } + /* try to charge at once */ + if (count > 1) { + struct res_counter *dummy; + /* + * "memcg" cannot be under rmdir() because we've already checked + * by cgroup_lock_live_cgroup() that it is not removed and we + * are still under the same cgroup_mutex. So we can postpone + * css_get(). + */ + if (res_counter_charge(&memcg->res, PAGE_SIZE * count, &dummy)) + goto one_by_one; + if (do_swap_account && res_counter_charge(&memcg->memsw, + PAGE_SIZE * count, &dummy)) { + res_counter_uncharge(&memcg->res, PAGE_SIZE * count); + goto one_by_one; + } + mc.precharge += count; + return ret; + } +one_by_one: + /* fall back to one by one charge */ + while (count--) { + if (signal_pending(current)) { + ret = -EINTR; + break; + } + if (!batch_count--) { + batch_count = PRECHARGE_COUNT_AT_ONCE; + cond_resched(); + } + ret = __mem_cgroup_try_charge(NULL, + GFP_KERNEL, 1, &memcg, false); + if (ret) + /* mem_cgroup_clear_mc() will do uncharge later */ + return ret; + mc.precharge++; + } + return ret; +} + +/** + * 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)) { + /* we don't move shared anon */ + if (!move_anon() || page_mapcount(page) > 2) + return NULL; + } else if (!move_file()) + /* we ignore mapcount for file pages */ + return NULL; + if (!get_page_unless_zero(page)) + return NULL; + + return page; +} + +static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, + unsigned long addr, pte_t ptent, swp_entry_t *entry) +{ + int usage_count; + struct page *page = NULL; + swp_entry_t ent = pte_to_swp_entry(ptent); + + if (!move_anon() || non_swap_entry(ent)) + return NULL; + usage_count = mem_cgroup_count_swap_user(ent, &page); + if (usage_count > 1) { /* we don't move shared anon */ + if (page) + put_page(page); + return NULL; + } + if (do_swap_account) + entry->val = ent.val; + + return page; +} + +static struct page *mc_handle_file_pte(struct vm_area_struct *vma, + unsigned long addr, pte_t ptent, swp_entry_t *entry) +{ + struct page *page = NULL; + struct inode *inode; + struct address_space *mapping; + pgoff_t pgoff; + + if (!vma->vm_file) /* anonymous vma */ + return NULL; + if (!move_file()) + return NULL; + + inode = vma->vm_file->f_path.dentry->d_inode; + mapping = vma->vm_file->f_mapping; + if (pte_none(ptent)) + pgoff = linear_page_index(vma, addr); + else /* pte_file(ptent) is true */ + pgoff = pte_to_pgoff(ptent); + + /* page is moved even if it's not RSS of this task(page-faulted). */ + page = find_get_page(mapping, pgoff); + +#ifdef CONFIG_SWAP + /* shmem/tmpfs may report page out on swap: account for that too. */ + if (radix_tree_exceptional_entry(page)) { + swp_entry_t swap = radix_to_swp_entry(page); + if (do_swap_account) + *entry = swap; + page = find_get_page(&swapper_space, swap.val); + } +#endif + return page; +} + +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; + struct page_cgroup *pc; + 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) || pte_file(ptent)) + page = mc_handle_file_pte(vma, addr, ptent, &ent); + + if (!page && !ent.val) + return ret; + if (page) { + pc = lookup_page_cgroup(page); + /* + * Do only loose check w/o page_cgroup lock. + * mem_cgroup_move_account() checks the pc is valid or not under + * the lock. + */ + if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) { + ret = MC_TARGET_PAGE; + if (target) + target->page = page; + } + if (!ret || !target) + put_page(page); + } + /* There is a swap entry and a page doesn't exist or isn't charged */ + if (ent.val && !ret && + css_id(&mc.from->css) == 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; + struct page_cgroup *pc; + enum mc_target_type ret = MC_TARGET_NONE; + + page = pmd_page(pmd); + VM_BUG_ON(!page || !PageHead(page)); + if (!move_anon()) + return ret; + pc = lookup_page_cgroup(page); + if (PageCgroupUsed(pc) && pc->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->private; + pte_t *pte; + spinlock_t *ptl; + + if (pmd_trans_huge_lock(pmd, vma) == 1) { + if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE) + mc.precharge += HPAGE_PMD_NR; + spin_unlock(&vma->vm_mm->page_table_lock); + 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 vm_area_struct *vma; + + down_read(&mm->mmap_sem); + for (vma = mm->mmap; vma; vma = vma->vm_next) { + struct mm_walk mem_cgroup_count_precharge_walk = { + .pmd_entry = mem_cgroup_count_precharge_pte_range, + .mm = mm, + .private = vma, + }; + if (is_vm_hugetlb_page(vma)) + continue; + walk_page_range(vma->vm_start, vma->vm_end, + &mem_cgroup_count_precharge_walk); + } + 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) { + __mem_cgroup_cancel_charge(mc.to, mc.precharge); + mc.precharge = 0; + } + /* + * we didn't uncharge from mc.from at mem_cgroup_move_account(), so + * we must uncharge here. + */ + if (mc.moved_charge) { + __mem_cgroup_cancel_charge(mc.from, mc.moved_charge); + mc.moved_charge = 0; + } + /* we must fixup refcnts and charges */ + if (mc.moved_swap) { + /* uncharge swap account from the old cgroup */ + if (!mem_cgroup_is_root(mc.from)) + res_counter_uncharge(&mc.from->memsw, + PAGE_SIZE * mc.moved_swap); + __mem_cgroup_put(mc.from, mc.moved_swap); + + if (!mem_cgroup_is_root(mc.to)) { + /* + * we charged both to->res and to->memsw, so we should + * uncharge to->res. + */ + res_counter_uncharge(&mc.to->res, + PAGE_SIZE * mc.moved_swap); + } + /* we've already done mem_cgroup_get(mc.to) */ + mc.moved_swap = 0; + } + memcg_oom_recover(from); + memcg_oom_recover(to); + wake_up_all(&mc.waitq); +} + +static void mem_cgroup_clear_mc(void) +{ + struct mem_cgroup *from = mc.from; + + /* + * we must clear moving_task before waking up waiters at the end of + * task migration. + */ + mc.moving_task = NULL; + __mem_cgroup_clear_mc(); + spin_lock(&mc.lock); + mc.from = NULL; + mc.to = NULL; + spin_unlock(&mc.lock); + mem_cgroup_end_move(from); +} + +static int mem_cgroup_can_attach(struct cgroup *cgroup, + struct cgroup_taskset *tset) +{ + struct task_struct *p = cgroup_taskset_first(tset); + int ret = 0; + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgroup); + + if (memcg->move_charge_at_immigrate) { + 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); + mem_cgroup_start_move(from); + spin_lock(&mc.lock); + mc.from = from; + mc.to = memcg; + 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 *cgroup, + struct cgroup_taskset *tset) +{ + 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->private; + pte_t *pte; + spinlock_t *ptl; + enum mc_target_type target_type; + union mc_target target; + struct page *page; + struct page_cgroup *pc; + + /* + * 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) == 1) { + if (mc.precharge < HPAGE_PMD_NR) { + spin_unlock(&vma->vm_mm->page_table_lock); + 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)) { + pc = lookup_page_cgroup(page); + if (!mem_cgroup_move_account(page, HPAGE_PMD_NR, + pc, mc.from, mc.to, + false)) { + mc.precharge -= HPAGE_PMD_NR; + mc.moved_charge += HPAGE_PMD_NR; + } + putback_lru_page(page); + } + put_page(page); + } + spin_unlock(&vma->vm_mm->page_table_lock); + 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; + pc = lookup_page_cgroup(page); + if (!mem_cgroup_move_account(page, 1, pc, + mc.from, mc.to, false)) { + 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, false)) { + 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 vm_area_struct *vma; + + lru_add_drain_all(); +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; + } + for (vma = mm->mmap; vma; vma = vma->vm_next) { + int ret; + struct mm_walk mem_cgroup_move_charge_walk = { + .pmd_entry = mem_cgroup_move_charge_pte_range, + .mm = mm, + .private = vma, + }; + if (is_vm_hugetlb_page(vma)) + continue; + ret = walk_page_range(vma->vm_start, vma->vm_end, + &mem_cgroup_move_charge_walk); + if (ret) + /* + * means we have consumed all precharges and failed in + * doing additional charge. Just abandon here. + */ + break; + } + up_read(&mm->mmap_sem); +} + +static void mem_cgroup_move_task(struct cgroup *cont, + 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); + put_swap_token(mm); + mmput(mm); + } + if (mc.to) + mem_cgroup_clear_mc(); +} +#else /* !CONFIG_MMU */ +static int mem_cgroup_can_attach(struct cgroup *cgroup, + struct cgroup_taskset *tset) +{ + return 0; +} +static void mem_cgroup_cancel_attach(struct cgroup *cgroup, + struct cgroup_taskset *tset) +{ +} +static void mem_cgroup_move_task(struct cgroup *cont, + struct cgroup_taskset *tset) +{ +} +#endif + +struct cgroup_subsys mem_cgroup_subsys = { + .name = "memory", + .subsys_id = mem_cgroup_subsys_id, + .create = mem_cgroup_create, + .pre_destroy = mem_cgroup_pre_destroy, + .destroy = mem_cgroup_destroy, + .populate = mem_cgroup_populate, + .can_attach = mem_cgroup_can_attach, + .cancel_attach = mem_cgroup_cancel_attach, + .attach = mem_cgroup_move_task, + .early_init = 0, + .use_id = 1, +}; + +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP +static int __init enable_swap_account(char *s) +{ + /* consider enabled if no parameter or 1 is given */ + 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); + +#endif |