| /* memcontrol.c - Memory Controller |
| * |
| * Copyright IBM Corporation, 2007 |
| * Author Balbir Singh <balbir@linux.vnet.ibm.com> |
| * |
| * Copyright 2007 OpenVZ SWsoft Inc |
| * Author: Pavel Emelianov <xemul@openvz.org> |
| * |
| * Memory thresholds |
| * Copyright (C) 2009 Nokia Corporation |
| * Author: Kirill A. Shutemov |
| * |
| * Kernel Memory Controller |
| * Copyright (C) 2012 Parallels Inc. and Google Inc. |
| * Authors: Glauber Costa and Suleiman Souhlal |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| */ |
| |
| #include <linux/res_counter.h> |
| #include <linux/memcontrol.h> |
| #include <linux/cgroup.h> |
| #include <linux/mm.h> |
| #include <linux/hugetlb.h> |
| #include <linux/pagemap.h> |
| #include <linux/smp.h> |
| #include <linux/page-flags.h> |
| #include <linux/backing-dev.h> |
| #include <linux/bit_spinlock.h> |
| #include <linux/rcupdate.h> |
| #include <linux/limits.h> |
| #include <linux/export.h> |
| #include <linux/mutex.h> |
| #include <linux/rbtree.h> |
| #include <linux/slab.h> |
| #include <linux/swap.h> |
| #include <linux/swapops.h> |
| #include <linux/spinlock.h> |
| #include <linux/eventfd.h> |
| #include <linux/poll.h> |
| #include <linux/sort.h> |
| #include <linux/fs.h> |
| #include <linux/seq_file.h> |
| #include <linux/vmpressure.h> |
| #include <linux/mm_inline.h> |
| #include <linux/page_cgroup.h> |
| #include <linux/cpu.h> |
| #include <linux/oom.h> |
| #include <linux/lockdep.h> |
| #include <linux/file.h> |
| #include "internal.h" |
| #include <net/sock.h> |
| #include <net/ip.h> |
| #include <net/tcp_memcontrol.h> |
| #include "slab.h" |
| |
| #include <asm/uaccess.h> |
| |
| #include <trace/events/vmscan.h> |
| |
| struct cgroup_subsys memory_cgrp_subsys __read_mostly; |
| EXPORT_SYMBOL(memory_cgrp_subsys); |
| |
| #define MEM_CGROUP_RECLAIM_RETRIES 5 |
| static struct mem_cgroup *root_mem_cgroup __read_mostly; |
| |
| #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 = 0; |
| #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 mem_cgroup_reclaim_iter { |
| /* |
| * last scanned hierarchy member. Valid only if last_dead_count |
| * matches memcg->dead_count of the hierarchy root group. |
| */ |
| struct mem_cgroup *last_visited; |
| int last_dead_count; |
| |
| /* scan generation, increased every round-trip */ |
| unsigned int generation; |
| }; |
| |
| /* |
| * per-zone information in memory controller. |
| */ |
| struct mem_cgroup_per_zone { |
| struct lruvec lruvec; |
| unsigned long lru_size[NR_LRU_LISTS]; |
| |
| struct mem_cgroup_reclaim_iter reclaim_iter[DEF_PRIORITY + 1]; |
| |
| struct rb_node tree_node; /* RB tree node */ |
| unsigned long long usage_in_excess;/* Set to the value by which */ |
| /* the soft limit is exceeded*/ |
| bool on_tree; |
| struct mem_cgroup *memcg; /* Back pointer, we cannot */ |
| /* use container_of */ |
| }; |
| |
| struct mem_cgroup_per_node { |
| struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; |
| }; |
| |
| /* |
| * Cgroups above their limits are maintained in a RB-Tree, independent of |
| * their hierarchy representation |
| */ |
| |
| struct mem_cgroup_tree_per_zone { |
| struct rb_root rb_root; |
| spinlock_t lock; |
| }; |
| |
| struct mem_cgroup_tree_per_node { |
| struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES]; |
| }; |
| |
| struct mem_cgroup_tree { |
| struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES]; |
| }; |
| |
| static struct mem_cgroup_tree soft_limit_tree __read_mostly; |
| |
| struct mem_cgroup_threshold { |
| struct eventfd_ctx *eventfd; |
| u64 threshold; |
| }; |
| |
| /* For threshold */ |
| struct mem_cgroup_threshold_ary { |
| /* An array index points to threshold just below 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; |
| /* |
| * the counter to account for memory usage |
| */ |
| struct res_counter res; |
| |
| /* vmpressure notifications */ |
| struct vmpressure vmpressure; |
| |
| /* |
| * the counter to account for mem+swap usage. |
| */ |
| struct res_counter memsw; |
| |
| /* |
| * the counter to account for kernel memory usage. |
| */ |
| struct res_counter kmem; |
| /* |
| * 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; |
| |
| /* set when res.limit == memsw.limit */ |
| bool memsw_is_minimum; |
| |
| /* protect arrays of thresholds */ |
| struct mutex thresholds_lock; |
| |
| /* thresholds for memory usage. RCU-protected */ |
| struct mem_cgroup_thresholds thresholds; |
| |
| /* thresholds for mem+swap usage. RCU-protected */ |
| struct mem_cgroup_thresholds memsw_thresholds; |
| |
| /* For oom notifier event fd */ |
| struct list_head oom_notify; |
| |
| /* |
| * Should we move charges of a task when a task is moved into this |
| * mem_cgroup ? And what type of charges should we move ? |
| */ |
| unsigned long move_charge_at_immigrate; |
| /* |
| * set > 0 if pages under this cgroup are moving to other cgroup. |
| */ |
| atomic_t moving_account; |
| /* taken only while moving_account > 0 */ |
| spinlock_t move_lock; |
| /* |
| * percpu counter. |
| */ |
| struct mem_cgroup_stat_cpu __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; |
| |
| atomic_t dead_count; |
| #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. per-memcg */ |
| struct list_head memcg_slab_caches; |
| /* Not a spinlock, we can take a lot of time walking the list */ |
| struct mutex slab_caches_mutex; |
| /* 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 */ |
| KMEM_ACCOUNTED_DEAD, /* dead memcg with pending kmem charges */ |
| }; |
| |
| #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); |
| } |
| |
| static void memcg_kmem_mark_dead(struct mem_cgroup *memcg) |
| { |
| /* |
| * Our caller must use css_get() first, because memcg_uncharge_kmem() |
| * will call css_put() if it sees the memcg is dead. |
| */ |
| smp_wmb(); |
| if (test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags)) |
| set_bit(KMEM_ACCOUNTED_DEAD, &memcg->kmem_account_flags); |
| } |
| |
| static bool memcg_kmem_test_and_clear_dead(struct mem_cgroup *memcg) |
| { |
| return test_and_clear_bit(KMEM_ACCOUNTED_DEAD, |
| &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) |
| |
| /* |
| * Reclaim flags for mem_cgroup_hierarchical_reclaim |
| */ |
| #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0 |
| #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT) |
| #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1 |
| #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT) |
| |
| /* |
| * 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) |
| { |
| /* |
| * The ID of the root cgroup is 0, but memcg treat 0 as an |
| * invalid ID, so we return (cgroup_id + 1). |
| */ |
| return memcg->css.cgroup->id + 1; |
| } |
| |
| static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id) |
| { |
| struct cgroup_subsys_state *css; |
| |
| css = css_from_id(id - 1, &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(&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 disarm_kmem_keys(struct mem_cgroup *memcg) |
| { |
| if (memcg_kmem_is_active(memcg)) { |
| static_key_slow_dec(&memcg_kmem_enabled_key); |
| ida_simple_remove(&kmem_limited_groups, memcg->kmemcg_id); |
| } |
| /* |
| * This check can't live in kmem destruction function, |
| * since the charges will outlive the cgroup |
| */ |
| WARN_ON(res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0); |
| } |
| #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 void drain_all_stock_async(struct mem_cgroup *memcg); |
| |
| static struct mem_cgroup_per_zone * |
| mem_cgroup_zoneinfo(struct mem_cgroup *memcg, int nid, int zid) |
| { |
| VM_BUG_ON((unsigned)nid >= nr_node_ids); |
| 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 * |
| page_cgroup_zoneinfo(struct mem_cgroup *memcg, struct page *page) |
| { |
| int nid = page_to_nid(page); |
| int zid = page_zonenum(page); |
| |
| return mem_cgroup_zoneinfo(memcg, nid, zid); |
| } |
| |
| static struct mem_cgroup_tree_per_zone * |
| soft_limit_tree_node_zone(int nid, int zid) |
| { |
| return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; |
| } |
| |
| static struct mem_cgroup_tree_per_zone * |
| soft_limit_tree_from_page(struct page *page) |
| { |
| int nid = page_to_nid(page); |
| int zid = page_zonenum(page); |
| |
| return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; |
| } |
| |
| static void |
| __mem_cgroup_insert_exceeded(struct mem_cgroup *memcg, |
| struct mem_cgroup_per_zone *mz, |
| struct mem_cgroup_tree_per_zone *mctz, |
| unsigned long long new_usage_in_excess) |
| { |
| struct rb_node **p = &mctz->rb_root.rb_node; |
| struct rb_node *parent = NULL; |
| struct mem_cgroup_per_zone *mz_node; |
| |
| if (mz->on_tree) |
| return; |
| |
| mz->usage_in_excess = new_usage_in_excess; |
| if (!mz->usage_in_excess) |
| return; |
| while (*p) { |
| parent = *p; |
| mz_node = rb_entry(parent, struct mem_cgroup_per_zone, |
| tree_node); |
| if (mz->usage_in_excess < mz_node->usage_in_excess) |
| p = &(*p)->rb_left; |
| /* |
| * We can't avoid mem cgroups that are over their soft |
| * limit by the same amount |
| */ |
| else if (mz->usage_in_excess >= mz_node->usage_in_excess) |
| p = &(*p)->rb_right; |
| } |
| rb_link_node(&mz->tree_node, parent, p); |
| rb_insert_color(&mz->tree_node, &mctz->rb_root); |
| mz->on_tree = true; |
| } |
| |
| static void |
| __mem_cgroup_remove_exceeded(struct mem_cgroup *memcg, |
| struct mem_cgroup_per_zone *mz, |
| struct mem_cgroup_tree_per_zone *mctz) |
| { |
| if (!mz->on_tree) |
| return; |
| rb_erase(&mz->tree_node, &mctz->rb_root); |
| mz->on_tree = false; |
| } |
| |
| static void |
| mem_cgroup_remove_exceeded(struct mem_cgroup *memcg, |
| struct mem_cgroup_per_zone *mz, |
| struct mem_cgroup_tree_per_zone *mctz) |
| { |
| spin_lock(&mctz->lock); |
| __mem_cgroup_remove_exceeded(memcg, mz, mctz); |
| spin_unlock(&mctz->lock); |
| } |
| |
| |
| static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page) |
| { |
| unsigned long long excess; |
| struct mem_cgroup_per_zone *mz; |
| struct mem_cgroup_tree_per_zone *mctz; |
| int nid = page_to_nid(page); |
| int zid = page_zonenum(page); |
| mctz = soft_limit_tree_from_page(page); |
| |
| /* |
| * Necessary to update all ancestors when hierarchy is used. |
| * because their event counter is not touched. |
| */ |
| for (; memcg; memcg = parent_mem_cgroup(memcg)) { |
| mz = mem_cgroup_zoneinfo(memcg, nid, zid); |
| excess = res_counter_soft_limit_excess(&memcg->res); |
| /* |
| * We have to update the tree if mz is on RB-tree or |
| * mem is over its softlimit. |
| */ |
| if (excess || mz->on_tree) { |
| spin_lock(&mctz->lock); |
| /* if on-tree, remove it */ |
| if (mz->on_tree) |
| __mem_cgroup_remove_exceeded(memcg, mz, mctz); |
| /* |
| * Insert again. mz->usage_in_excess will be updated. |
| * If excess is 0, no tree ops. |
| */ |
| __mem_cgroup_insert_exceeded(memcg, mz, mctz, excess); |
| spin_unlock(&mctz->lock); |
| } |
| } |
| } |
| |
| static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg) |
| { |
| int node, zone; |
| struct mem_cgroup_per_zone *mz; |
| struct mem_cgroup_tree_per_zone *mctz; |
| |
| for_each_node(node) { |
| for (zone = 0; zone < MAX_NR_ZONES; zone++) { |
| mz = mem_cgroup_zoneinfo(memcg, node, zone); |
| mctz = soft_limit_tree_node_zone(node, zone); |
| mem_cgroup_remove_exceeded(memcg, mz, mctz); |
| } |
| } |
| } |
| |
| static struct mem_cgroup_per_zone * |
| __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) |
| { |
| struct rb_node *rightmost = NULL; |
| struct mem_cgroup_per_zone *mz; |
| |
| retry: |
| mz = NULL; |
| rightmost = rb_last(&mctz->rb_root); |
| if (!rightmost) |
| goto done; /* Nothing to reclaim from */ |
| |
| mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node); |
| /* |
| * Remove the node now but someone else can add it back, |
| * we will to add it back at the end of reclaim to its correct |
| * position in the tree. |
| */ |
| __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz); |
| if (!res_counter_soft_limit_excess(&mz->memcg->res) || |
| !css_tryget(&mz->memcg->css)) |
| goto retry; |
| done: |
| return mz; |
| } |
| |
| static struct mem_cgroup_per_zone * |
| mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) |
| { |
| struct mem_cgroup_per_zone *mz; |
| |
| spin_lock(&mctz->lock); |
| mz = __mem_cgroup_largest_soft_limit_node(mctz); |
| spin_unlock(&mctz->lock); |
| return mz; |
| } |
| |
| /* |
| * Implementation Note: reading percpu statistics for memcg. |
| * |
| * Both of vmstat[] and percpu_counter has threshold and do periodic |
| * synchronization to implement "quick" read. There are trade-off between |
| * reading cost and precision of value. Then, we may have a chance to implement |
| * a periodic synchronizion of counter in memcg's counter. |
| * |
| * But this _read() function is used for user interface now. The user accounts |
| * memory usage by memory cgroup and he _always_ requires exact value because |
| * he accounts memory. Even if we provide quick-and-fuzzy read, we always |
| * have to visit all online cpus and make sum. So, for now, unnecessary |
| * synchronization is not implemented. (just implemented for cpu hotplug) |
| * |
| * If there are kernel internal actions which can make use of some not-exact |
| * value, and reading all cpu value can be performance bottleneck in some |
| * common workload, threashold and synchonization as vmstat[] should be |
| * implemented. |
| */ |
| static long mem_cgroup_read_stat(struct mem_cgroup *memcg, |
| enum mem_cgroup_stat_index idx) |
| { |
| long val = 0; |
| int cpu; |
| |
| get_online_cpus(); |
| for_each_online_cpu(cpu) |
| val += per_cpu(memcg->stat->count[idx], cpu); |
| #ifdef CONFIG_HOTPLUG_CPU |
| spin_lock(&memcg->pcp_counter_lock); |
| val += memcg->nocpu_base.count[idx]; |
| spin_unlock(&memcg->pcp_counter_lock); |
| #endif |
| put_online_cpus(); |
| return val; |
| } |
| |
| static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg, |
| bool charge) |
| { |
| int val = (charge) ? 1 : -1; |
| this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], 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, |
| bool anon, 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 (anon) |
| __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS], |
| nr_pages); |
| else |
| __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE], |
| nr_pages); |
| |
| 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_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid, |
| unsigned int lru_mask) |
| { |
| struct mem_cgroup_per_zone *mz; |
| enum lru_list lru; |
| unsigned long ret = 0; |
| |
| mz = mem_cgroup_zoneinfo(memcg, nid, zid); |
| |
| for_each_lru(lru) { |
| if (BIT(lru) & lru_mask) |
| ret += mz->lru_size[lru]; |
| } |
| return ret; |
| } |
| |
| static unsigned long |
| mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg, |
| int nid, unsigned int lru_mask) |
| { |
| u64 total = 0; |
| int zid; |
| |
| for (zid = 0; zid < MAX_NR_ZONES; zid++) |
| total += mem_cgroup_zone_nr_lru_pages(memcg, |
| nid, zid, lru_mask); |
| |
| return total; |
| } |
| |
| static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg, |
| unsigned int lru_mask) |
| { |
| int nid; |
| u64 total = 0; |
| |
| for_each_node_state(nid, N_MEMORY) |
| total += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask); |
| return total; |
| } |
| |
| static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, |
| enum mem_cgroup_events_target target) |
| { |
| unsigned long val, next; |
| |
| val = __this_cpu_read(memcg->stat->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) |
| { |
| preempt_disable(); |
| /* threshold event is triggered in finer grain than soft limit */ |
| if (unlikely(mem_cgroup_event_ratelimit(memcg, |
| MEM_CGROUP_TARGET_THRESH))) { |
| bool do_softlimit; |
| bool do_numainfo __maybe_unused; |
| |
| do_softlimit = mem_cgroup_event_ratelimit(memcg, |
| MEM_CGROUP_TARGET_SOFTLIMIT); |
| #if MAX_NUMNODES > 1 |
| do_numainfo = mem_cgroup_event_ratelimit(memcg, |
| MEM_CGROUP_TARGET_NUMAINFO); |
| #endif |
| preempt_enable(); |
| |
| mem_cgroup_threshold(memcg); |
| if (unlikely(do_softlimit)) |
| mem_cgroup_update_tree(memcg, page); |
| #if MAX_NUMNODES > 1 |
| if (unlikely(do_numainfo)) |
| atomic_inc(&memcg->numainfo_events); |
| #endif |
| } else |
| preempt_enable(); |
| } |
| |
| struct mem_cgroup *mem_cgroup_from_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(&memcg->css)); |
| rcu_read_unlock(); |
| return memcg; |
| } |
| |
| /* |
| * Returns a next (in a pre-order walk) alive memcg (with elevated css |
| * ref. count) or NULL if the whole root's subtree has been visited. |
| * |
| * helper function to be used by mem_cgroup_iter |
| */ |
| static struct mem_cgroup *__mem_cgroup_iter_next(struct mem_cgroup *root, |
| struct mem_cgroup *last_visited) |
| { |
| struct cgroup_subsys_state *prev_css, *next_css; |
| |
| prev_css = last_visited ? &last_visited->css : NULL; |
| skip_node: |
| next_css = css_next_descendant_pre(prev_css, &root->css); |
| |
| /* |
| * Even if we found a group we have to make sure it is |
| * alive. css && !memcg means that the groups should be |
| * skipped and we should continue the tree walk. |
| * last_visited css is safe to use because it is |
| * protected by css_get and the tree walk is rcu safe. |
| * |
| * We do not take a reference on the root of the tree walk |
| * because we might race with the root removal when it would |
| * be the only node in the iterated hierarchy and mem_cgroup_iter |
| * would end up in an endless loop because it expects that at |
| * least one valid node will be returned. Root cannot disappear |
| * because caller of the iterator should hold it already so |
| * skipping css reference should be safe. |
| */ |
| if (next_css) { |
| if ((next_css == &root->css) || |
| ((next_css->flags & CSS_ONLINE) && css_tryget(next_css))) |
| return mem_cgroup_from_css(next_css); |
| |
| prev_css = next_css; |
| goto skip_node; |
| } |
| |
| return NULL; |
| } |
| |
| static void mem_cgroup_iter_invalidate(struct mem_cgroup *root) |
| { |
| /* |
| * When a group in the hierarchy below root is destroyed, the |
| * hierarchy iterator can no longer be trusted since it might |
| * have pointed to the destroyed group. Invalidate it. |
| */ |
| atomic_inc(&root->dead_count); |
| } |
| |
| static struct mem_cgroup * |
| mem_cgroup_iter_load(struct mem_cgroup_reclaim_iter *iter, |
| struct mem_cgroup *root, |
| int *sequence) |
| { |
| struct mem_cgroup *position = NULL; |
| /* |
| * A cgroup destruction happens in two stages: offlining and |
| * release. They are separated by a RCU grace period. |
| * |
| * If the iterator is valid, we may still race with an |
| * offlining. The RCU lock ensures the object won't be |
| * released, tryget will fail if we lost the race. |
| */ |
| *sequence = atomic_read(&root->dead_count); |
| if (iter->last_dead_count == *sequence) { |
| smp_rmb(); |
| position = iter->last_visited; |
| |
| /* |
| * We cannot take a reference to root because we might race |
| * with root removal and returning NULL would end up in |
| * an endless loop on the iterator user level when root |
| * would be returned all the time. |
| */ |
| if (position && position != root && |
| !css_tryget(&position->css)) |
| position = NULL; |
| } |
| return position; |
| } |
| |
| static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter *iter, |
| struct mem_cgroup *last_visited, |
| struct mem_cgroup *new_position, |
| struct mem_cgroup *root, |
| int sequence) |
| { |
| /* root reference counting symmetric to mem_cgroup_iter_load */ |
| if (last_visited && last_visited != root) |
| css_put(&last_visited->css); |
| /* |
| * We store the sequence count from the time @last_visited was |
| * loaded successfully instead of rereading it here so that we |
| * don't lose destruction events in between. We could have |
| * raced with the destruction of @new_position after all. |
| */ |
| iter->last_visited = new_position; |
| smp_wmb(); |
| iter->last_dead_count = sequence; |
| } |
| |
| /** |
| * mem_cgroup_iter - iterate over memory cgroup hierarchy |
| * @root: hierarchy root |
| * @prev: previously returned memcg, NULL on first invocation |
| * @reclaim: cookie for shared reclaim walks, NULL for full walks |
| * |
| * Returns references to children of the hierarchy below @root, or |
| * @root itself, or %NULL after a full round-trip. |
| * |
| * Caller must pass the return value in @prev on subsequent |
| * invocations for reference counting, or use mem_cgroup_iter_break() |
| * to cancel a hierarchy walk before the round-trip is complete. |
| * |
| * Reclaimers can specify a zone and a priority level in @reclaim to |
| * divide up the memcgs in the hierarchy among all concurrent |
| * reclaimers operating on the same zone and priority. |
| */ |
| struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, |
| struct mem_cgroup *prev, |
| struct mem_cgroup_reclaim_cookie *reclaim) |
| { |
| struct mem_cgroup *memcg = NULL; |
| struct mem_cgroup *last_visited = NULL; |
| |
| if (mem_cgroup_disabled()) |
| return NULL; |
| |
| if (!root) |
| root = root_mem_cgroup; |
| |
| if (prev && !reclaim) |
| last_visited = prev; |
| |
| if (!root->use_hierarchy && root != root_mem_cgroup) { |
| if (prev) |
| goto out_css_put; |
| return root; |
| } |
| |
| rcu_read_lock(); |
| while (!memcg) { |
| struct mem_cgroup_reclaim_iter *uninitialized_var(iter); |
| int uninitialized_var(seq); |
| |
| if (reclaim) { |
| int nid = zone_to_nid(reclaim->zone); |
| int zid = zone_idx(reclaim->zone); |
| struct mem_cgroup_per_zone *mz; |
| |
| mz = mem_cgroup_zoneinfo(root, nid, zid); |
| iter = &mz->reclaim_iter[reclaim->priority]; |
| if (prev && reclaim->generation != iter->generation) { |
| iter->last_visited = NULL; |
| goto out_unlock; |
| } |
| |
| last_visited = mem_cgroup_iter_load(iter, root, &seq); |
| } |
| |
| memcg = __mem_cgroup_iter_next(root, last_visited); |
| |
| if (reclaim) { |
| mem_cgroup_iter_update(iter, last_visited, memcg, root, |
| seq); |
| |
| if (!memcg) |
| iter->generation++; |
| else if (!prev && memcg) |
| reclaim->generation = iter->generation; |
| } |
| |
| if (prev && !memcg) |
| goto out_unlock; |
| } |
| out_unlock: |
| rcu_read_unlock(); |
| out_css_put: |
| 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_zoneinfo(memcg, zone_to_nid(zone), zone_idx(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; |
| } |
| |
| /* |
| * Following LRU functions are allowed to be used without PCG_LOCK. |
| * Operations are called by routine of global LRU independently from memcg. |
| * What we have to take care of here is validness of pc->mem_cgroup. |
| * |
| * Changes to pc->mem_cgroup happens when |
| * 1. charge |
| * 2. moving account |
| * In typical case, "charge" is done before add-to-lru. Exception is SwapCache. |
| * It is added to LRU before charge. |
| * If PCG_USED bit is not set, page_cgroup is not added to this private LRU. |
| * When moving account, the page is not on LRU. It's isolated. |
| */ |
| |
| /** |
| * mem_cgroup_page_lruvec - return lruvec for adding an lru page |
| * @page: the page |
| * @zone: zone of the page |
| */ |
| 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; |
| |
| /* |
| * Surreptitiously switch any uncharged offlist page to root: |
| * an uncharged page off lru does nothing to secure |
| * its former mem_cgroup from sudden removal. |
| * |
| * Our caller holds lru_lock, and PageCgroupUsed is updated |
| * under page_cgroup lock: between them, they make all uses |
| * of pc->mem_cgroup safe. |
| */ |
| if (!PageLRU(page) && !PageCgroupUsed(pc) && memcg != root_mem_cgroup) |
| pc->mem_cgroup = memcg = root_mem_cgroup; |
| |
| mz = page_cgroup_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_res_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 long margin; |
| |
| margin = res_counter_margin(&memcg->res); |
| if (do_swap_account) |
| margin = min(margin, res_counter_margin(&memcg->memsw)); |
| return margin >> PAGE_SHIFT; |
| } |
| |
| int mem_cgroup_swappiness(struct mem_cgroup *memcg) |
| { |
| /* root ? */ |
| if (!css_parent(&memcg->css)) |
| return vm_swappiness; |
| |
| return memcg->swappiness; |
| } |
| |
| /* |
| * memcg->moving_account is used for checking possibility that some thread is |
| * calling move_account(). When a thread on CPU-A starts moving pages under |
| * a memcg, other threads should check memcg->moving_account under |
| * rcu_read_lock(), like this: |
| * |
| * CPU-A CPU-B |
| * rcu_read_lock() |
| * memcg->moving_account+1 if (memcg->mocing_account) |
| * take heavy locks. |
| * synchronize_rcu() update something. |
| * rcu_read_unlock() |
| * start move here. |
| */ |
| |
| /* for quick checking without looking up memcg */ |
| atomic_t memcg_moving __read_mostly; |
| |
| static void mem_cgroup_start_move(struct mem_cgroup *memcg) |
| { |
| atomic_inc(&memcg_moving); |
| atomic_inc(&memcg->moving_account); |
| synchronize_rcu(); |
| } |
| |
| static void mem_cgroup_end_move(struct mem_cgroup *memcg) |
| { |
| /* |
| * Now, mem_cgroup_clear_mc() may call this function with NULL. |
| * We check NULL in callee rather than caller. |
| */ |
| if (memcg) { |
| atomic_dec(&memcg_moving); |
| atomic_dec(&memcg->moving_account); |
| } |
| } |
| |
| /* |
| * 2 routines for checking "mem" is under move_account() or not. |
| * |
| * mem_cgroup_stolen() - checking whether a cgroup is mc.from or not. This |
| * is used for avoiding races in accounting. If true, |
| * pc->mem_cgroup may be overwritten. |
| * |
| * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or |
| * under hierarchy of moving cgroups. This is for |
| * waiting at hith-memory prressure caused by "move". |
| */ |
| |
| static bool mem_cgroup_stolen(struct mem_cgroup *memcg) |
| { |
| VM_BUG_ON(!rcu_read_lock_held()); |
| return atomic_read(&memcg->moving_account) > 0; |
| } |
| |
| static bool mem_cgroup_under_move(struct mem_cgroup *memcg) |
| { |
| struct mem_cgroup *from; |
| struct mem_cgroup *to; |
| bool ret = false; |
| /* |
| * Unlike task_move routines, we access mc.to, mc.from not under |
| * mutual exclusion by cgroup_mutex. Here, we take spinlock instead. |
| */ |
| spin_lock(&mc.lock); |
| from = mc.from; |
| to = mc.to; |
| if (!from) |
| goto unlock; |
| |
| ret = mem_cgroup_same_or_subtree(memcg, from) |
| || mem_cgroup_same_or_subtree(memcg, to); |
| unlock: |
| spin_unlock(&mc.lock); |
| return ret; |
| } |
| |
| static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg) |
| { |
| if (mc.moving_task && current != mc.moving_task) { |
| if (mem_cgroup_under_move(memcg)) { |
| DEFINE_WAIT(wait); |
| prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE); |
| /* moving charge context might have finished. */ |
| if (mc.moving_task) |
| schedule(); |
| finish_wait(&mc.waitq, &wait); |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /* |
| * Take this lock when |
| * - a code tries to modify page's memcg while it's USED. |
| * - a code tries to modify page state accounting in a memcg. |
| * see mem_cgroup_stolen(), too. |
| */ |
| static void move_lock_mem_cgroup(struct mem_cgroup *memcg, |
| unsigned long *flags) |
| { |
| spin_lock_irqsave(&memcg->move_lock, *flags); |
| } |
| |
| static void move_unlock_mem_cgroup(struct mem_cgroup *memcg, |
| unsigned long *flags) |
| { |
| spin_unlock_irqrestore(&memcg->move_lock, *flags); |
| } |
| |
| #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 %llu\n", |
| res_counter_read_u64(&memcg->res, RES_USAGE) >> 10, |
| res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10, |
| res_counter_read_u64(&memcg->res, RES_FAILCNT)); |
| pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %llu\n", |
| res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10, |
| res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10, |
| res_counter_read_u64(&memcg->memsw, RES_FAILCNT)); |
| pr_info("kmem: usage %llukB, limit %llukB, failcnt %llu\n", |
| res_counter_read_u64(&memcg->kmem, RES_USAGE) >> 10, |
| res_counter_read_u64(&memcg->kmem, RES_LIMIT) >> 10, |
| res_counter_read_u64(&memcg->kmem, RES_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 u64 mem_cgroup_get_limit(struct mem_cgroup *memcg) |
| { |
| u64 limit; |
| |
| limit = res_counter_read_u64(&memcg->res, RES_LIMIT); |
| |
| /* |
| * Do not consider swap space if we cannot swap due to swappiness |
| */ |
| if (mem_cgroup_swappiness(memcg)) { |
| u64 memsw; |
| |
| limit += total_swap_pages << PAGE_SHIFT; |
| memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT); |
| |
| /* |
| * If memsw is finite and limits the amount of swap space |
| * available to this memcg, return that limit. |
| */ |
| limit = min(limit, memsw); |
| } |
| |
| 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) >> PAGE_SHIFT ? : 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"); |
| } |
| |
| static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg, |
| gfp_t gfp_mask, |
| unsigned long flags) |
| { |
| unsigned long total = 0; |
| bool noswap = false; |
| int loop; |
| |
| if (flags & MEM_CGROUP_RECLAIM_NOSWAP) |
| noswap = true; |
| if (!(flags & MEM_CGROUP_RECLAIM_SHRINK) && memcg->memsw_is_minimum) |
| noswap = true; |
| |
| for (loop = 0; loop < MEM_CGROUP_MAX_RECLAIM_LOOPS; loop++) { |
| if (loop) |
| drain_all_stock_async(memcg); |
| total += try_to_free_mem_cgroup_pages(memcg, gfp_mask, noswap); |
| /* |
| * Allow limit shrinkers, which are triggered directly |
| * by userspace, to catch signals and stop reclaim |
| * after minimal progress, regardless of the margin. |
| */ |
| if (total && (flags & MEM_CGROUP_RECLAIM_SHRINK)) |
| break; |
| if (mem_cgroup_margin(memcg)) |
| break; |
| /* |
| * If nothing was reclaimed after two attempts, there |
| * may be no reclaimable pages in this hierarchy. |
| */ |
| if (loop && !total) |
| break; |
| } |
| return total; |
| } |
| |
| /** |
| * test_mem_cgroup_node_reclaimable |
| * @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 = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT; |
| |
| while (1) { |
| victim = mem_cgroup_iter(root_memcg, victim, &reclaim); |
| if (!victim) { |
| loop++; |
| if (loop >= 2) { |
| /* |
| * If we have not been able to reclaim |
| * anything, it might because there are |
| * no reclaimable pages under this hierarchy |
| */ |
| if (!total) |
| break; |
| /* |
| * We want to do more targeted reclaim. |
| * excess >> 2 is not to excessive so as to |
| * reclaim too much, nor too less that we keep |
| * coming back to reclaim from this cgroup |
| */ |
| if (total >= (excess >> 2) || |
| (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) |
| break; |
| } |
| continue; |
| } |
| if (!mem_cgroup_reclaimable(victim, false)) |
| continue; |
| total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false, |
| zone, &nr_scanned); |
| *total_scanned += nr_scanned; |
| if (!res_counter_soft_limit_excess(&root_memcg->res)) |
| break; |
| } |
| mem_cgroup_iter_break(root_memcg, victim); |
| return total; |
| } |
| |
| #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; |
| } |
| |
| /* |
| * Currently used to update mapped file statistics, but the routine can be |
| * generalized to update other statistics as well. |
| * |
| * Notes: Race condition |
| * |
| * We usually use page_cgroup_lock() for accessing page_cgroup member but |
| * it tends to be costly. But considering some conditions, we doesn't need |
| * to do so _always_. |
| * |
| * Considering "charge", lock_page_cgroup() is not required because all |
| * file-stat operations happen after a page is attached to radix-tree. There |
| * are no race with "charge". |
| * |
| * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup |
| * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even |
| * if there are race with "uncharge". Statistics itself is properly handled |
| * by flags. |
| * |
| * Considering "move", this is an only case we see a race. To make the race |
| * small, we check mm->moving_account and detect there are possibility of race |
| * If there is, we take a lock. |
| */ |
| |
| void __mem_cgroup_begin_update_page_stat(struct page *page, |
| bool *locked, unsigned long *flags) |
| { |
| struct mem_cgroup *memcg; |
| struct page_cgroup *pc; |
| |
| pc = lookup_page_cgroup(page); |
| again: |
| memcg = pc->mem_cgroup; |
| if (unlikely(!memcg || !PageCgroupUsed(pc))) |
| return; |
| /* |
| * If this memory cgroup is not under account moving, we don't |
| * need to take move_lock_mem_cgroup(). Because we already hold |
| * rcu_read_lock(), any calls to move_account will be delayed until |
| * rcu_read_unlock() if mem_cgroup_stolen() == true. |
| */ |
| if (!mem_cgroup_stolen(memcg)) |
| return; |
| |
| move_lock_mem_cgroup(memcg, flags); |
| if (memcg != pc->mem_cgroup || !PageCgroupUsed(pc)) { |
| move_unlock_mem_cgroup(memcg, flags); |
| goto again; |
| } |
| *locked = true; |
| } |
| |
| void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags) |
| { |
| struct page_cgroup *pc = lookup_page_cgroup(page); |
| |
| /* |
| * It's guaranteed that pc->mem_cgroup never changes while |
| * lock is held because a routine modifies pc->mem_cgroup |
| * should take move_lock_mem_cgroup(). |
| */ |
| move_unlock_mem_cgroup(pc->mem_cgroup, flags); |
| } |
| |
| void mem_cgroup_update_page_stat(struct page *page, |
| enum mem_cgroup_stat_index idx, int val) |
| { |
| struct mem_cgroup *memcg; |
| struct page_cgroup *pc = lookup_page_cgroup(page); |
| unsigned long uninitialized_var(flags); |
| |
| if (mem_cgroup_disabled()) |
| return; |
| |
| VM_BUG_ON(!rcu_read_lock_held()); |
| memcg = pc->mem_cgroup; |
| if (unlikely(!memcg || !PageCgroupUsed(pc))) |
| return; |
| |
| 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 = true; |
| |
| if (nr_pages > CHARGE_BATCH) |
| return false; |
| |
| stock = &get_cpu_var(memcg_stock); |
| if (memcg == stock->cached && stock->nr_pages >= nr_pages) |
| stock->nr_pages -= nr_pages; |
| else /* need to call res_counter_charge */ |
| ret = false; |
| put_cpu_var(memcg_stock); |
| return ret; |
| } |
| |
| /* |
| * Returns stocks cached in percpu to res_counter and reset cached information. |
| */ |
| static void drain_stock(struct memcg_stock_pcp *stock) |
| { |
| struct mem_cgroup *old = stock->cached; |
| |
| if (stock->nr_pages) { |
| unsigned long bytes = stock->nr_pages * PAGE_SIZE; |
| |
| res_counter_uncharge(&old->res, bytes); |
| if (do_swap_account) |
| res_counter_uncharge(&old->memsw, bytes); |
| stock->nr_pages = 0; |
| } |
| stock->cached = NULL; |
| } |
| |
| /* |
| * This must be called under preempt disabled or must be called by |
| * a thread which is pinned to local cpu. |
| */ |
| static void drain_local_stock(struct work_struct *dummy) |
| { |
| struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock); |
| drain_stock(stock); |
| clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); |
| } |
| |
| 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) which is from res_counter, to local per_cpu area. |
| * This will be consumed by consume_stock() function, later. |
| */ |
| static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages) |
| { |
| struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock); |
| |
| if (stock->cached != memcg) { /* reset if necessary */ |
| drain_stock(stock); |
| stock->cached = memcg; |
| } |
| stock->nr_pages += nr_pages; |
| put_cpu_var(memcg_stock); |
| } |
| |
| /* |
| * Drains all per-CPU charge caches for given root_memcg resp. subtree |
| * of the hierarchy under it. sync flag says whether we should block |
| * until the work is done. |
| */ |
| static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync) |
| { |
| int cpu, curcpu; |
| |
| /* Notify other cpus that system-wide "drain" is running */ |
| get_online_cpus(); |
| curcpu = get_cpu(); |
| for_each_online_cpu(cpu) { |
| struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); |
| struct mem_cgroup *memcg; |
| |
| memcg = stock->cached; |
| if (!memcg || !stock->nr_pages) |
| continue; |
| if (!mem_cgroup_same_or_subtree(root_memcg, memcg)) |
| continue; |
| if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) { |
| if (cpu == curcpu) |
| drain_local_stock(&stock->work); |
| else |
| schedule_work_on(cpu, &stock->work); |
| } |
| } |
| put_cpu(); |
| |
| if (!sync) |
| goto out; |
| |
| for_each_online_cpu(cpu) { |
| struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); |
| if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) |
| flush_work(&stock->work); |
| } |
| out: |
| put_online_cpus(); |
| } |
| |
| /* |
| * Tries to drain stocked charges in other cpus. This function is asynchronous |
| * and just put a work per cpu for draining localy on each cpu. Caller can |
| * expects some charges will be back to res_counter later but cannot wait for |
| * it. |
| */ |
| static void drain_all_stock_async(struct mem_cgroup *root_memcg) |
| { |
| /* |
| * If someone calls draining, avoid adding more kworker runs. |
| */ |
| if (!mutex_trylock(&percpu_charge_mutex)) |
| return; |
| drain_all_stock(root_memcg, false); |
| mutex_unlock(&percpu_charge_mutex); |
| } |
| |
| /* This is a synchronous drain interface. */ |
| static void drain_all_stock_sync(struct mem_cgroup *root_memcg) |
| { |
| /* called when force_empty is called */ |
| mutex_lock(&percpu_charge_mutex); |
| drain_all_stock(root_memcg, true); |
| mutex_unlock(&percpu_charge_mutex); |
| } |
| |
| /* |
| * This function drains percpu counter value from DEAD cpu and |
| * move it to local cpu. Note that this function can be preempted. |
| */ |
| static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu) |
| { |
| int i; |
| |
| spin_lock(&memcg->pcp_counter_lock); |
| for (i = 0; i < MEM_CGROUP_STAT_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; |
| } |
| |
| |
| /* See mem_cgroup_try_charge() for details */ |
| enum { |
| CHARGE_OK, /* success */ |
| CHARGE_RETRY, /* need to retry but retry is not bad */ |
| CHARGE_NOMEM, /* we can't do more. return -ENOMEM */ |
| CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */ |
| }; |
| |
| static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, |
| unsigned int nr_pages, unsigned int min_pages, |
| bool invoke_oom) |
| { |
| unsigned long csize = nr_pages * PAGE_SIZE; |
| struct mem_cgroup *mem_over_limit; |
| struct res_counter *fail_res; |
| unsigned long flags = 0; |
| int ret; |
| |
| ret = res_counter_charge(&memcg->res, csize, &fail_res); |
| |
| if (likely(!ret)) { |
| if (!do_swap_account) |
| return CHARGE_OK; |
| ret = res_counter_charge(&memcg->memsw, csize, &fail_res); |
| if (likely(!ret)) |
| return CHARGE_OK; |
| |
| res_counter_uncharge(&memcg->res, csize); |
| mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw); |
| flags |= MEM_CGROUP_RECLAIM_NOSWAP; |
| } else |
| mem_over_limit = mem_cgroup_from_res_counter(fail_res, res); |
| /* |
| * Never reclaim on behalf of optional batching, retry with a |
| * single page instead. |
| */ |
| if (nr_pages > min_pages) |
| return CHARGE_RETRY; |
| |
| if (!(gfp_mask & __GFP_WAIT)) |
| return CHARGE_WOULDBLOCK; |
| |
| if (gfp_mask & __GFP_NORETRY) |
| return CHARGE_NOMEM; |
| |
| ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags); |
| if (mem_cgroup_margin(mem_over_limit) >= nr_pages) |
| return CHARGE_RETRY; |
| /* |
| * Even though the limit is exceeded at this point, reclaim |
| * may have been able to free some pages. Retry the charge |
| * before killing the task. |
| * |
| * Only for regular pages, though: huge pages are rather |
| * unlikely to succeed so close to the limit, and we fall back |
| * to regular pages anyway in case of failure. |
| */ |
| if (nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER) && ret) |
| return CHARGE_RETRY; |
| |
| /* |
| * At task move, charge accounts can be doubly counted. So, it's |
| * better to wait until the end of task_move if something is going on. |
| */ |
| if (mem_cgroup_wait_acct_move(mem_over_limit)) |
| return CHARGE_RETRY; |
| |
| if (invoke_oom) |
| mem_cgroup_oom(mem_over_limit, gfp_mask, get_order(csize)); |
| |
| return CHARGE_NOMEM; |
| } |
| |
| /** |
| * mem_cgroup_try_charge - try charging a memcg |
| * @memcg: memcg to charge |
| * @nr_pages: number of pages to charge |
| * @oom: trigger OOM if reclaim fails |
| * |
| * Returns 0 if @memcg was charged successfully, -EINTR if the charge |
| * was bypassed to root_mem_cgroup, and -ENOMEM if the charge failed. |
| */ |
| static int mem_cgroup_try_charge(struct mem_cgroup *memcg, |
| gfp_t gfp_mask, |
| unsigned int nr_pages, |
| bool oom) |
| { |
| unsigned int batch = max(CHARGE_BATCH, nr_pages); |
| int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; |
| int ret; |
| |
| if (mem_cgroup_is_root(memcg)) |
| goto done; |
| /* |
| * 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))) |
| goto bypass; |
| |
| if (unlikely(task_in_memcg_oom(current))) |
| goto nomem; |
| |
| if (gfp_mask & __GFP_NOFAIL) |
| oom = false; |
| again: |
| if (consume_stock(memcg, nr_pages)) |
| goto done; |
| |
| do { |
| bool invoke_oom = oom && !nr_oom_retries; |
| |
| /* If killed, bypass charge */ |
| if (fatal_signal_pending(current)) |
| goto bypass; |
| |
| ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, |
| nr_pages, invoke_oom); |
| switch (ret) { |
| case CHARGE_OK: |
| break; |
| case CHARGE_RETRY: /* not in OOM situation but retry */ |
| batch = nr_pages; |
| goto again; |
| case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */ |
| goto nomem; |
| case CHARGE_NOMEM: /* OOM routine works */ |
| if (!oom || invoke_oom) |
| goto nomem; |
| nr_oom_retries--; |
| break; |
| } |
| } while (ret != CHARGE_OK); |
| |
| if (batch > nr_pages) |
| refill_stock(memcg, batch - nr_pages); |
| done: |
| return 0; |
| nomem: |
| if (!(gfp_mask & __GFP_NOFAIL)) |
| return -ENOMEM; |
| bypass: |
| return -EINTR; |
| } |
| |
| /** |
| * mem_cgroup_try_charge_mm - try charging a mm |
| * @mm: mm_struct to charge |
| * @nr_pages: number of pages to charge |
| * @oom: trigger OOM if reclaim fails |
| * |
| * Returns the charged mem_cgroup associated with the given mm_struct or |
| * NULL the charge failed. |
| */ |
| static struct mem_cgroup *mem_cgroup_try_charge_mm(struct mm_struct *mm, |
| gfp_t gfp_mask, |
| unsigned int nr_pages, |
| bool oom) |
| |
| { |
| struct mem_cgroup *memcg; |
| int ret; |
| |
| memcg = get_mem_cgroup_from_mm(mm); |
| ret = mem_cgroup_try_charge(memcg, gfp_mask, nr_pages, oom); |
| css_put(&memcg->css); |
| if (ret == -EINTR) |
| memcg = root_mem_cgroup; |
| else if (ret) |
| memcg = NULL; |
| |
| return memcg; |
| } |
| |
| /* |
| * Somemtimes we have to undo a charge we got by try_charge(). |
| * This function is for that and do uncharge, put css's refcnt. |
| * gotten by try_charge(). |
| */ |
| static void __mem_cgroup_cancel_charge(struct mem_cgroup *memcg, |
| unsigned int nr_pages) |
| { |
| if (!mem_cgroup_is_root(memcg)) { |
| unsigned long bytes = nr_pages * PAGE_SIZE; |
| |
| res_counter_uncharge(&memcg->res, bytes); |
| if (do_swap_account) |
| res_counter_uncharge(&memcg->memsw, bytes); |
| } |
| } |
| |
| /* |
| * Cancel chrages in this cgroup....doesn't propagate to parent cgroup. |
| * This is useful when moving usage to parent cgroup. |
| */ |
| static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg, |
| unsigned int nr_pages) |
| { |
| unsigned long bytes = nr_pages * PAGE_SIZE; |
| |
| if (mem_cgroup_is_root(memcg)) |
| return; |
| |
| res_counter_uncharge_until(&memcg->res, memcg->res.parent, bytes); |
| if (do_swap_account) |
| res_counter_uncharge_until(&memcg->memsw, |
| memcg->memsw.parent, bytes); |
| } |
| |
| /* |
| * A helper function to get mem_cgroup from ID. must be called under |
| * rcu_read_lock(). The caller is responsible for calling css_tryget 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); |
| } |
| |
| 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); |
| lock_page_cgroup(pc); |
| if (PageCgroupUsed(pc)) { |
| memcg = pc->mem_cgroup; |
| if (memcg && !css_tryget(&memcg->css)) |
| memcg = NULL; |
| } else if (PageSwapCache(page)) { |
| ent.val = page_private(page); |
| id = lookup_swap_cgroup_id(ent); |
| rcu_read_lock(); |
| memcg = mem_cgroup_lookup(id); |
| if (memcg && !css_tryget(&memcg->css)) |
| memcg = NULL; |
| rcu_read_unlock(); |
| } |
| unlock_page_cgroup(pc); |
| return memcg; |
| } |
| |
| static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, |
| struct page *page, |
| unsigned int nr_pages, |
| enum charge_type ctype, |
| bool lrucare) |
| { |
| struct page_cgroup *pc = lookup_page_cgroup(page); |
| struct zone *uninitialized_var(zone); |
| struct lruvec *lruvec; |
| bool was_on_lru = false; |
| bool anon; |
| |
| lock_page_cgroup(pc); |
| 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) { |
| zone = page_zone(page); |
| spin_lock_irq(&zone->lru_lock); |
| if (PageLRU(page)) { |
| lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup); |
| ClearPageLRU(page); |
| del_page_from_lru_list(page, lruvec, page_lru(page)); |
| was_on_lru = true; |
| } |
| } |
| |
| pc->mem_cgroup = memcg; |
| /* |
| * We access a page_cgroup asynchronously without lock_page_cgroup(). |
| * Especially when a page_cgroup is taken from a page, pc->mem_cgroup |
| * is accessed after testing USED bit. To make pc->mem_cgroup visible |
| * before USED bit, we need memory barrier here. |
| * See mem_cgroup_add_lru_list(), etc. |
| */ |
| smp_wmb(); |
| SetPageCgroupUsed(pc); |
| |
| if (lrucare) { |
| if (was_on_lru) { |
| lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup); |
| 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); |
| } |
| |
| if (ctype == MEM_CGROUP_CHARGE_TYPE_ANON) |
| anon = true; |
| else |
| anon = false; |
| |
| mem_cgroup_charge_statistics(memcg, page, anon, nr_pages); |
| unlock_page_cgroup(pc); |
| |
| /* |
| * "charge_statistics" updated event counter. Then, check it. |
| * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree. |
| * if they exceeds softlimit. |
| */ |
| memcg_check_events(memcg, page); |
| } |
| |
| static DEFINE_MUTEX(set_limit_mutex); |
| |
| #ifdef CONFIG_MEMCG_KMEM |
| static DEFINE_MUTEX(activate_kmem_mutex); |
| |
| static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg) |
| { |
| return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) && |
| memcg_kmem_is_active(memcg); |
| } |
| |
| /* |
| * 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_can_account_kmem(memcg)) |
| return -EIO; |
| |
| print_slabinfo_header(m); |
| |
| mutex_lock(&memcg->slab_caches_mutex); |
| list_for_each_entry(params, &memcg->memcg_slab_caches, list) |
| cache_show(memcg_params_to_cache(params), m); |
| mutex_unlock(&memcg->slab_caches_mutex); |
| |
| return 0; |
| } |
| #endif |
| |
| static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, u64 size) |
| { |
| struct res_counter *fail_res; |
| int ret = 0; |
| |
| ret = res_counter_charge(&memcg->kmem, size, &fail_res); |
| if (ret) |
| return ret; |
| |
| ret = mem_cgroup_try_charge(memcg, gfp, size >> PAGE_SHIFT, |
| oom_gfp_allowed(gfp)); |
| if (ret == -EINTR) { |
| /* |
| * mem_cgroup_try_charge() chosed 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 |
| * mem_cgroup_try_charge() above. Tasks that were already |
| * dying when the allocation triggers should have been already |
| * directed to the root cgroup in memcontrol.h |
| */ |
| res_counter_charge_nofail(&memcg->res, size, &fail_res); |
| if (do_swap_account) |
| res_counter_charge_nofail(&memcg->memsw, size, |
| &fail_res); |
| ret = 0; |
| } else if (ret) |
| res_counter_uncharge(&memcg->kmem, size); |
| |
| return ret; |
| } |
| |
| static void memcg_uncharge_kmem(struct mem_cgroup *memcg, u64 size) |
| { |
| res_counter_uncharge(&memcg->res, size); |
| if (do_swap_account) |
| res_counter_uncharge(&memcg->memsw, size); |
| |
| /* Not down to 0 */ |
| if (res_counter_uncharge(&memcg->kmem, size)) |
| return; |
| |
| /* |
| * Releases a reference taken in kmem_cgroup_css_offline in case |
| * this last uncharge is racing with the offlining code or it is |
| * outliving the memcg existence. |
| * |
| * The memory barrier imposed by test&clear is paired with the |
| * explicit one in memcg_kmem_mark_dead(). |
| */ |
| if (memcg_kmem_test_and_clear_dead(memcg)) |
| css_put(&memcg->css); |
| } |
| |
| /* |
| * 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 size_t memcg_caches_array_size(int num_groups) |
| { |
| ssize_t size; |
| if (num_groups <= 0) |
| return 0; |
| |
| size = 2 * num_groups; |
| if (size < MEMCG_CACHES_MIN_SIZE) |
| size = MEMCG_CACHES_MIN_SIZE; |
| else if (size > MEMCG_CACHES_MAX_SIZE) |
| size = MEMCG_CACHES_MAX_SIZE; |
| |
| return size; |
| } |
| |
| /* |
| * 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) |
| { |
| if (num > memcg_limited_groups_array_size) |
| memcg_limited_groups_array_size = memcg_caches_array_size(num); |
| } |
| |
| static void kmem_cache_destroy_work_func(struct work_struct *w); |
| |
| int memcg_update_cache_size(struct kmem_cache *s, int num_groups) |
| { |
| struct memcg_cache_params *cur_params = s->memcg_params; |
| |
| VM_BUG_ON(!is_root_cache(s)); |
| |
| if (num_groups > memcg_limited_groups_array_size) { |
| int i; |
| struct memcg_cache_params *new_params; |
| ssize_t size = memcg_caches_array_size(num_groups); |
| |
| size *= sizeof(void *); |
| size += offsetof(struct memcg_cache_params, memcg_caches); |
| |
| new_params = kzalloc(size, GFP_KERNEL); |
| if (!new_params) |
| return -ENOMEM; |
| |
| new_params->is_root_cache = true; |
| |
| /* |
| * There is the chance it will be bigger than |
| * memcg_limited_groups_array_size, if we failed an allocation |
| * in a cache, in which case all caches updated before it, will |
| * have a bigger array. |
| * |
| * But if that is the case, the data after |
| * memcg_limited_groups_array_size is certainly unused |
| */ |
| for (i = 0; i < memcg_limited_groups_array_size; i++) { |
| if (!cur_params->memcg_caches[i]) |
| continue; |
| new_params->memcg_caches[i] = |
| cur_params->memcg_caches[i]; |
| } |
| |
| /* |
| * Ideally, we would wait until all caches succeed, and only |
| * then free the old one. But this is not worth the extra |
| * pointer per-cache we'd have to have for this. |
| * |
| * It is not a big deal if some caches are left with a size |
| * bigger than the others. And all updates will reset this |
| * anyway. |
| */ |
| rcu_assign_pointer(s->memcg_params, new_params); |
| if (cur_params) |
| kfree_rcu(cur_params, rcu_head); |
| } |
| return 0; |
| } |
| |
| char *memcg_create_cache_name(struct mem_cgroup *memcg, |
| struct kmem_cache *root_cache) |
| { |
| static char *buf = NULL; |
| |
| /* |
| * We need a mutex here to protect the shared buffer. Since this is |
| * expected to be called only on cache creation, we can employ the |
| * slab_mutex for that purpose. |
| */ |
| lockdep_assert_held(&slab_mutex); |
| |
| if (!buf) { |
| buf = kmalloc(NAME_MAX + 1, GFP_KERNEL); |
| if (!buf) |
| return NULL; |
| } |
| |
| cgroup_name(memcg->css.cgroup, buf, NAME_MAX + 1); |
| return kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name, |
| memcg_cache_id(memcg), buf); |
| } |
| |
| int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s, |
| struct kmem_cache *root_cache) |
| { |
| size_t size; |
| |
| if (!memcg_kmem_enabled()) |
| return 0; |
| |
| if (!memcg) { |
| size = offsetof(struct memcg_cache_params, memcg_caches); |
| size += memcg_limited_groups_array_size * sizeof(void *); |
| } else |
| size = sizeof(struct memcg_cache_params); |
| |
| s->memcg_params = kzalloc(size, GFP_KERNEL); |
| if (!s->memcg_params) |
| return -ENOMEM; |
| |
| if (memcg) { |
| s->memcg_params->memcg = memcg; |
| s->memcg_params->root_cache = root_cache; |
| INIT_WORK(&s->memcg_params->destroy, |
| kmem_cache_destroy_work_func); |
| css_get(&memcg->css); |
| } else |
| s->memcg_params->is_root_cache = true; |
| |
| return 0; |
| } |
| |
| void memcg_free_cache_params(struct kmem_cache *s) |
| { |
| if (!s->memcg_params) |
| return; |
| if (!s->memcg_params->is_root_cache) |
| css_put(&s->memcg_params->memcg->css); |
| kfree(s->memcg_params); |
| } |
| |
| void memcg_register_cache(struct kmem_cache *s) |
| { |
| struct kmem_cache *root; |
| struct mem_cgroup *memcg; |
| int id; |
| |
| if (is_root_cache(s)) |
| return; |
| |
| /* |
| * Holding the slab_mutex assures nobody will touch the memcg_caches |
| * array while we are modifying it. |
| */ |
| lockdep_assert_held(&slab_mutex); |
| |
| root = s->memcg_params->root_cache; |
| memcg = s->memcg_params->memcg; |
| id = memcg_cache_id(memcg); |
| |
| /* |
| * 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(); |
| |
| /* |
| * Initialize the pointer to this cache in its parent's memcg_params |
| * before adding it to the memcg_slab_caches list, otherwise we can |
| * fail to convert memcg_params_to_cache() while traversing the list. |
| */ |
| VM_BUG_ON(root->memcg_params->memcg_caches[id]); |
| root->memcg_params->memcg_caches[id] = s; |
| |
| mutex_lock(&memcg->slab_caches_mutex); |
| list_add(&s->memcg_params->list, &memcg->memcg_slab_caches); |
| mutex_unlock(&memcg->slab_caches_mutex); |
| } |
| |
| void memcg_unregister_cache(struct kmem_cache *s) |
| { |
| struct kmem_cache *root; |
| struct mem_cgroup *memcg; |
| int id; |
| |
| if (is_root_cache(s)) |
| return; |
| |
| /* |
| * Holding the slab_mutex assures nobody will touch the memcg_caches |
| * array while we are modifying it. |
| */ |
| lockdep_assert_held(&slab_mutex); |
| |
| root = s->memcg_params->root_cache; |
| memcg = s->memcg_params->memcg; |
| id = memcg_cache_id(memcg); |
| |
| mutex_lock(&memcg->slab_caches_mutex); |
| list_del(&s->memcg_params->list); |
| mutex_unlock(&memcg->slab_caches_mutex); |
| |
| /* |
| * Clear the pointer to this cache in its parent's memcg_params only |
| * after removing it from the memcg_slab_caches list, otherwise we can |
| * fail to convert memcg_params_to_cache() while traversing the list. |
| */ |
| VM_BUG_ON(root->memcg_params->memcg_caches[id] != s); |
| root->memcg_params->memcg_caches[id] = NULL; |
| } |
| |
| /* |
| * 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--; |
| } |
| |
| static void kmem_cache_destroy_work_func(struct work_struct *w) |
| { |
| struct kmem_cache *cachep; |
| struct memcg_cache_params *p; |
| |
| p = container_of(w, struct memcg_cache_params, destroy); |
| |
| cachep = memcg_params_to_cache(p); |
| |
| /* |
| * If we get down to 0 after shrink, we could delete right away. |
| * However, memcg_release_pages() already puts us back in the workqueue |
| * in that case. If we proceed deleting, we'll get a dangling |
| * reference, and removing the object from the workqueue in that case |
| * is unnecessary complication. We are not a fast path. |
| * |
| * Note that this case is fundamentally different from racing with |
| * shrink_slab(): if memcg_cgroup_destroy_cache() is called in |
| * kmem_cache_shrink, not only we would be reinserting a dead cache |
| * into the queue, but doing so from inside the worker racing to |
| * destroy it. |
| * |
| * So if we aren't down to zero, we'll just schedule a worker and try |
| * again |
| */ |
| if (atomic_read(&cachep->memcg_params->nr_pages) != 0) |
| kmem_cache_shrink(cachep); |
| else |
| kmem_cache_destroy(cachep); |
| } |
| |
| void mem_cgroup_destroy_cache(struct kmem_cache *cachep) |
| { |
| if (!cachep->memcg_params->dead) |
| return; |
| |
| /* |
| * There are many ways in which we can get here. |
| * |
| * We can get to a memory-pressure situation while the delayed work is |
| * still pending to run. The vmscan shrinkers can then release all |
| * cache memory and get us to destruction. If this is the case, we'll |
| * be executed twice, which is a bug (the second time will execute over |
| * bogus data). In this case, cancelling the work should be fine. |
| * |
| * But we can also get here from the worker itself, if |
| * kmem_cache_shrink is enough to shake all the remaining objects and |
| * get the page count to 0. In this case, we'll deadlock if we try to |
| * cancel the work (the worker runs with an internal lock held, which |
| * is the same lock we would hold for cancel_work_sync().) |
| * |
| * Since we can't possibly know who got us here, just refrain from |
| * running if there is already work pending |
| */ |
| if (work_pending(&cachep->memcg_params->destroy)) |
| return; |
| /* |
| * We have to defer the actual destroying to a workqueue, because |
| * we might currently be in a context that cannot sleep. |
| */ |
| schedule_work(&cachep->memcg_params->destroy); |
| } |
| |
| int __kmem_cache_destroy_memcg_children(struct kmem_cache *s) |
| { |
| struct kmem_cache *c; |
| int i, failed = 0; |
| |
| /* |
| * If the cache is being destroyed, we trust that there is no one else |
| * requesting objects from it. Even if there are, the sanity checks in |
| * kmem_cache_destroy should caught this ill-case. |
| * |
| * Still, we don't want anyone else freeing memcg_caches under our |
| * noses, which can happen if a new memcg comes to life. As usual, |
| * we'll take the activate_kmem_mutex to protect ourselves against |
| * this. |
| */ |
| mutex_lock(&activate_kmem_mutex); |
| for_each_memcg_cache_index(i) { |
| c = cache_from_memcg_idx(s, i); |
| if (!c) |
| continue; |
| |
| /* |
| * We will now manually delete the caches, so to avoid races |
| * we need to cancel all pending destruction workers and |
| * proceed with destruction ourselves. |
| * |
| * kmem_cache_destroy() will call kmem_cache_shrink internally, |
| * and that could spawn the workers again: it is likely that |
| * the cache still have active pages until this very moment. |
| * This would lead us back to mem_cgroup_destroy_cache. |
| * |
| * But that will not execute at all if the "dead" flag is not |
| * set, so flip it down to guarantee we are in control. |
| */ |
| c->memcg_params->dead = false; |
| cancel_work_sync(&c->memcg_params->destroy); |
| kmem_cache_destroy(c); |
| |
| if (cache_from_memcg_idx(s, i)) |
| failed++; |
| } |
| mutex_unlock(&activate_kmem_mutex); |
| return failed; |
| } |
| |
| |