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