diff options
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 9846 |
1 files changed, 4237 insertions, 5609 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index d12ca6f3c293..be810c1fbfc3 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* memcontrol.c - Memory Controller * * Copyright IBM Corporation, 2007 @@ -14,23 +15,27 @@ * 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. + * Native page reclaim + * Charge lifetime sanitation + * Lockless page tracking & accounting + * Unified hierarchy configuration model + * Copyright (C) 2015 Red Hat, Inc., Johannes Weiner * - * This program is 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. + * Per memcg lru locking + * Copyright (C) 2020 Alibaba, Inc, Alex Shi */ -#include <linux/res_counter.h> +#include <linux/cgroup-defs.h> +#include <linux/page_counter.h> #include <linux/memcontrol.h> #include <linux/cgroup.h> -#include <linux/mm.h> +#include <linux/cpuset.h> +#include <linux/sched/mm.h> +#include <linux/shmem_fs.h> #include <linux/hugetlb.h> #include <linux/pagemap.h> +#include <linux/pagevec.h> +#include <linux/vm_event_item.h> #include <linux/smp.h> #include <linux/page-flags.h> #include <linux/backing-dev.h> @@ -38,1008 +43,834 @@ #include <linux/rcupdate.h> #include <linux/limits.h> #include <linux/export.h> +#include <linux/list.h> #include <linux/mutex.h> #include <linux/rbtree.h> #include <linux/slab.h> -#include <linux/swap.h> #include <linux/swapops.h> #include <linux/spinlock.h> -#include <linux/eventfd.h> -#include <linux/sort.h> #include <linux/fs.h> #include <linux/seq_file.h> -#include <linux/vmalloc.h> #include <linux/vmpressure.h> +#include <linux/memremap.h> #include <linux/mm_inline.h> -#include <linux/page_cgroup.h> +#include <linux/swap_cgroup.h> #include <linux/cpu.h> #include <linux/oom.h> +#include <linux/lockdep.h> +#include <linux/resume_user_mode.h> +#include <linux/psi.h> +#include <linux/seq_buf.h> +#include <linux/sched/isolation.h> +#include <linux/kmemleak.h> #include "internal.h" #include <net/sock.h> #include <net/ip.h> -#include <net/tcp_memcontrol.h> +#include "slab.h" +#include "memcontrol-v1.h" -#include <asm/uaccess.h> +#include <linux/uaccess.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/memcg.h> +#undef CREATE_TRACE_POINTS #include <trace/events/vmscan.h> -struct cgroup_subsys mem_cgroup_subsys __read_mostly; -EXPORT_SYMBOL(mem_cgroup_subsys); +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; +struct mem_cgroup *root_mem_cgroup __read_mostly; +EXPORT_SYMBOL(root_mem_cgroup); -#ifdef CONFIG_MEMCG_SWAP -/* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */ -int do_swap_account __read_mostly; +/* Active memory cgroup to use from an interrupt context */ +DEFINE_PER_CPU(struct mem_cgroup *, int_active_memcg); +EXPORT_PER_CPU_SYMBOL_GPL(int_active_memcg); -/* 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 +/* Socket memory accounting disabled? */ +static bool cgroup_memory_nosocket __ro_after_init; -#else -#define do_swap_account 0 +/* Kernel memory accounting disabled? */ +static bool cgroup_memory_nokmem __ro_after_init; + +/* BPF memory accounting disabled? */ +static bool cgroup_memory_nobpf __ro_after_init; + +static struct kmem_cache *memcg_cachep; +static struct kmem_cache *memcg_pn_cachep; + +#ifdef CONFIG_CGROUP_WRITEBACK +static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq); #endif +static inline bool task_is_dying(void) +{ + return tsk_is_oom_victim(current) || fatal_signal_pending(current) || + (current->flags & PF_EXITING); +} -/* - * Statistics for memory cgroup. - */ -enum mem_cgroup_stat_index { - /* - * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss. - */ - MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */ - MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */ - MEM_CGROUP_STAT_RSS_HUGE, /* # of pages charged as anon huge */ - MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */ - MEM_CGROUP_STAT_SWAP, /* # of pages, swapped out */ - MEM_CGROUP_STAT_NSTATS, -}; +/* Some nice accessors for the vmpressure. */ +struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg) +{ + if (!memcg) + memcg = root_mem_cgroup; + return &memcg->vmpressure; +} -static const char * const mem_cgroup_stat_names[] = { - "cache", - "rss", - "rss_huge", - "mapped_file", - "swap", -}; +struct mem_cgroup *vmpressure_to_memcg(struct vmpressure *vmpr) +{ + return container_of(vmpr, struct mem_cgroup, vmpressure); +} -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, -}; +#define SEQ_BUF_SIZE SZ_4K +#define CURRENT_OBJCG_UPDATE_BIT 0 +#define CURRENT_OBJCG_UPDATE_FLAG (1UL << CURRENT_OBJCG_UPDATE_BIT) -static const char * const mem_cgroup_events_names[] = { - "pgpgin", - "pgpgout", - "pgfault", - "pgmajfault", -}; +static DEFINE_SPINLOCK(objcg_lock); -static const char * const mem_cgroup_lru_names[] = { - "inactive_anon", - "active_anon", - "inactive_file", - "active_file", - "unevictable", -}; +bool mem_cgroup_kmem_disabled(void) +{ + return cgroup_memory_nokmem; +} -/* - * 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]; -}; +static void memcg_uncharge(struct mem_cgroup *memcg, unsigned int nr_pages); + +static void obj_cgroup_release(struct percpu_ref *ref) +{ + struct obj_cgroup *objcg = container_of(ref, struct obj_cgroup, refcnt); + unsigned int nr_bytes; + unsigned int nr_pages; + unsigned long flags; -struct mem_cgroup_reclaim_iter { /* - * last scanned hierarchy member. Valid only if last_dead_count - * matches memcg->dead_count of the hierarchy root group. + * At this point all allocated objects are freed, and + * objcg->nr_charged_bytes can't have an arbitrary byte value. + * However, it can be PAGE_SIZE or (x * PAGE_SIZE). + * + * The following sequence can lead to it: + * 1) CPU0: objcg == stock->cached_objcg + * 2) CPU1: we do a small allocation (e.g. 92 bytes), + * PAGE_SIZE bytes are charged + * 3) CPU1: a process from another memcg is allocating something, + * the stock if flushed, + * objcg->nr_charged_bytes = PAGE_SIZE - 92 + * 5) CPU0: we do release this object, + * 92 bytes are added to stock->nr_bytes + * 6) CPU0: stock is flushed, + * 92 bytes are added to objcg->nr_charged_bytes + * + * In the result, nr_charged_bytes == PAGE_SIZE. + * This page will be uncharged in obj_cgroup_release(). */ - struct mem_cgroup *last_visited; - unsigned long last_dead_count; + nr_bytes = atomic_read(&objcg->nr_charged_bytes); + WARN_ON_ONCE(nr_bytes & (PAGE_SIZE - 1)); + nr_pages = nr_bytes >> PAGE_SHIFT; - /* scan generation, increased every round-trip */ - unsigned int generation; -}; + if (nr_pages) { + struct mem_cgroup *memcg; -/* - * 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 */ -}; + memcg = get_mem_cgroup_from_objcg(objcg); + mod_memcg_state(memcg, MEMCG_KMEM, -nr_pages); + memcg1_account_kmem(memcg, -nr_pages); + if (!mem_cgroup_is_root(memcg)) + memcg_uncharge(memcg, nr_pages); + mem_cgroup_put(memcg); + } -struct mem_cgroup_per_node { - struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; -}; + spin_lock_irqsave(&objcg_lock, flags); + list_del(&objcg->list); + spin_unlock_irqrestore(&objcg_lock, flags); -/* - * Cgroups above their limits are maintained in a RB-Tree, independent of - * their hierarchy representation - */ + percpu_ref_exit(ref); + kfree_rcu(objcg, rcu); +} -struct mem_cgroup_tree_per_zone { - struct rb_root rb_root; - spinlock_t lock; -}; +static struct obj_cgroup *obj_cgroup_alloc(void) +{ + struct obj_cgroup *objcg; + int ret; -struct mem_cgroup_tree_per_node { - struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES]; -}; + objcg = kzalloc(sizeof(struct obj_cgroup), GFP_KERNEL); + if (!objcg) + return NULL; -struct mem_cgroup_tree { - struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES]; -}; + ret = percpu_ref_init(&objcg->refcnt, obj_cgroup_release, 0, + GFP_KERNEL); + if (ret) { + kfree(objcg); + return NULL; + } + INIT_LIST_HEAD(&objcg->list); + return objcg; +} -static struct mem_cgroup_tree soft_limit_tree __read_mostly; +static void memcg_reparent_objcgs(struct mem_cgroup *memcg, + struct mem_cgroup *parent) +{ + struct obj_cgroup *objcg, *iter; -struct mem_cgroup_threshold { - struct eventfd_ctx *eventfd; - u64 threshold; -}; + objcg = rcu_replace_pointer(memcg->objcg, NULL, true); -/* 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]; -}; + spin_lock_irq(&objcg_lock); -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; -}; + /* 1) Ready to reparent active objcg. */ + list_add(&objcg->list, &memcg->objcg_list); + /* 2) Reparent active objcg and already reparented objcgs to parent. */ + list_for_each_entry(iter, &memcg->objcg_list, list) + WRITE_ONCE(iter->memcg, parent); + /* 3) Move already reparented objcgs to the parent's list */ + list_splice(&memcg->objcg_list, &parent->objcg_list); -/* for OOM */ -struct mem_cgroup_eventfd_list { - struct list_head list; - struct eventfd_ctx *eventfd; -}; + spin_unlock_irq(&objcg_lock); -static void mem_cgroup_threshold(struct mem_cgroup *memcg); -static void mem_cgroup_oom_notify(struct mem_cgroup *memcg); + percpu_ref_kill(&objcg->refcnt); +} /* - * 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. + * A lot of the calls to the cache allocation functions are expected to be + * inlined by the compiler. Since the calls to memcg_slab_post_alloc_hook() 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 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; +DEFINE_STATIC_KEY_FALSE(memcg_kmem_online_key); +EXPORT_SYMBOL(memcg_kmem_online_key); - int swappiness; - /* OOM-Killer disable */ - int oom_kill_disable; +DEFINE_STATIC_KEY_FALSE(memcg_bpf_enabled_key); +EXPORT_SYMBOL(memcg_bpf_enabled_key); - /* set when res.limit == memsw.limit */ - bool memsw_is_minimum; - - /* protect arrays of thresholds */ - struct mutex thresholds_lock; +/** + * mem_cgroup_css_from_folio - css of the memcg associated with a folio + * @folio: folio of interest + * + * If memcg is bound to the default hierarchy, css of the memcg associated + * with @folio is returned. The returned css remains associated with @folio + * until it is released. + * + * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup + * is returned. + */ +struct cgroup_subsys_state *mem_cgroup_css_from_folio(struct folio *folio) +{ + struct mem_cgroup *memcg = folio_memcg(folio); - /* thresholds for memory usage. RCU-protected */ - struct mem_cgroup_thresholds thresholds; + if (!memcg || !cgroup_subsys_on_dfl(memory_cgrp_subsys)) + memcg = root_mem_cgroup; - /* thresholds for mem+swap usage. RCU-protected */ - struct mem_cgroup_thresholds memsw_thresholds; + return &memcg->css; +} - /* For oom notifier event fd */ - struct list_head oom_notify; +/** + * page_cgroup_ino - return inode number of the memcg a page is charged to + * @page: the page + * + * Look up the closest online ancestor of the memory cgroup @page is charged to + * and return its inode number or 0 if @page is not charged to any cgroup. It + * is safe to call this function without holding a reference to @page. + * + * Note, this function is inherently racy, because there is nothing to prevent + * the cgroup inode from getting torn down and potentially reallocated a moment + * after page_cgroup_ino() returns, so it only should be used by callers that + * do not care (such as procfs interfaces). + */ +ino_t page_cgroup_ino(struct page *page) +{ + struct mem_cgroup *memcg; + unsigned long ino = 0; - /* - * 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; + rcu_read_lock(); + /* page_folio() is racy here, but the entire function is racy anyway */ + memcg = folio_memcg_check(page_folio(page)); - atomic_t dead_count; -#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET) - struct tcp_memcontrol tcp_mem; + while (memcg && !(memcg->css.flags & CSS_ONLINE)) + memcg = parent_mem_cgroup(memcg); + if (memcg) + ino = cgroup_ino(memcg->css.cgroup); + rcu_read_unlock(); + return ino; +} +EXPORT_SYMBOL_GPL(page_cgroup_ino); + +/* Subset of node_stat_item for memcg stats */ +static const unsigned int memcg_node_stat_items[] = { + NR_INACTIVE_ANON, + NR_ACTIVE_ANON, + NR_INACTIVE_FILE, + NR_ACTIVE_FILE, + NR_UNEVICTABLE, + NR_SLAB_RECLAIMABLE_B, + NR_SLAB_UNRECLAIMABLE_B, + WORKINGSET_REFAULT_ANON, + WORKINGSET_REFAULT_FILE, + WORKINGSET_ACTIVATE_ANON, + WORKINGSET_ACTIVATE_FILE, + WORKINGSET_RESTORE_ANON, + WORKINGSET_RESTORE_FILE, + WORKINGSET_NODERECLAIM, + NR_ANON_MAPPED, + NR_FILE_MAPPED, + NR_FILE_PAGES, + NR_FILE_DIRTY, + NR_WRITEBACK, + NR_SHMEM, + NR_SHMEM_THPS, + NR_FILE_THPS, + NR_ANON_THPS, + NR_KERNEL_STACK_KB, + NR_PAGETABLE, + NR_SECONDARY_PAGETABLE, +#ifdef CONFIG_SWAP + NR_SWAPCACHE, #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; +#ifdef CONFIG_NUMA_BALANCING + PGPROMOTE_SUCCESS, #endif - - int last_scanned_node; -#if MAX_NUMNODES > 1 - nodemask_t scan_nodes; - atomic_t numainfo_events; - atomic_t numainfo_updating; + PGDEMOTE_KSWAPD, + PGDEMOTE_DIRECT, + PGDEMOTE_KHUGEPAGED, + PGDEMOTE_PROACTIVE, +#ifdef CONFIG_HUGETLB_PAGE + NR_HUGETLB, #endif - - struct mem_cgroup_per_node *nodeinfo[0]; - /* WARNING: nodeinfo must be the last member here */ }; -static size_t memcg_size(void) -{ - return sizeof(struct mem_cgroup) + - nr_node_ids * sizeof(struct mem_cgroup_per_node); -} - -/* internal only representation about the status of kmem accounting. */ -enum { - KMEM_ACCOUNTED_ACTIVE = 0, /* accounted by this cgroup itself */ - KMEM_ACCOUNTED_ACTIVATED, /* static key enabled. */ - KMEM_ACCOUNTED_DEAD, /* dead memcg with pending kmem charges */ +static const unsigned int memcg_stat_items[] = { + MEMCG_SWAP, + MEMCG_SOCK, + MEMCG_PERCPU_B, + MEMCG_VMALLOC, + MEMCG_KMEM, + MEMCG_ZSWAP_B, + MEMCG_ZSWAPPED, }; -/* We account when limit is on, but only after call sites are patched */ -#define KMEM_ACCOUNTED_MASK \ - ((1 << KMEM_ACCOUNTED_ACTIVE) | (1 << KMEM_ACCOUNTED_ACTIVATED)) +#define NR_MEMCG_NODE_STAT_ITEMS ARRAY_SIZE(memcg_node_stat_items) +#define MEMCG_VMSTAT_SIZE (NR_MEMCG_NODE_STAT_ITEMS + \ + ARRAY_SIZE(memcg_stat_items)) +#define BAD_STAT_IDX(index) ((u32)(index) >= U8_MAX) +static u8 mem_cgroup_stats_index[MEMCG_NR_STAT] __read_mostly; -#ifdef CONFIG_MEMCG_KMEM -static inline void memcg_kmem_set_active(struct mem_cgroup *memcg) +static void init_memcg_stats(void) { - set_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags); -} + u8 i, j = 0; -static bool memcg_kmem_is_active(struct mem_cgroup *memcg) -{ - return test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags); -} + BUILD_BUG_ON(MEMCG_NR_STAT >= U8_MAX); -static void memcg_kmem_set_activated(struct mem_cgroup *memcg) -{ - set_bit(KMEM_ACCOUNTED_ACTIVATED, &memcg->kmem_account_flags); -} + memset(mem_cgroup_stats_index, U8_MAX, sizeof(mem_cgroup_stats_index)); -static void memcg_kmem_clear_activated(struct mem_cgroup *memcg) -{ - clear_bit(KMEM_ACCOUNTED_ACTIVATED, &memcg->kmem_account_flags); -} + for (i = 0; i < NR_MEMCG_NODE_STAT_ITEMS; ++i, ++j) + mem_cgroup_stats_index[memcg_node_stat_items[i]] = j; -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); + for (i = 0; i < ARRAY_SIZE(memcg_stat_items); ++i, ++j) + mem_cgroup_stats_index[memcg_stat_items[i]] = j; } -static bool memcg_kmem_test_and_clear_dead(struct mem_cgroup *memcg) +static inline int memcg_stats_index(int idx) { - return test_and_clear_bit(KMEM_ACCOUNTED_DEAD, - &memcg->kmem_account_flags); + return mem_cgroup_stats_index[idx]; } -#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, +struct lruvec_stats_percpu { + /* Local (CPU and cgroup) state */ + long state[NR_MEMCG_NODE_STAT_ITEMS]; + + /* Delta calculation for lockless upward propagation */ + long state_prev[NR_MEMCG_NODE_STAT_ITEMS]; }; -/* "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), +struct lruvec_stats { + /* Aggregated (CPU and subtree) state */ + long state[NR_MEMCG_NODE_STAT_ITEMS]; + + /* Non-hierarchical (CPU aggregated) state */ + long state_local[NR_MEMCG_NODE_STAT_ITEMS]; + + /* Pending child counts during tree propagation */ + long state_pending[NR_MEMCG_NODE_STAT_ITEMS]; }; -static bool move_anon(void) +unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx) { - return test_bit(MOVE_CHARGE_TYPE_ANON, &mc.immigrate_flags); + struct mem_cgroup_per_node *pn; + long x; + int i; + + if (mem_cgroup_disabled()) + return node_page_state(lruvec_pgdat(lruvec), idx); + + i = memcg_stats_index(idx); + if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, idx)) + return 0; + + pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec); + x = READ_ONCE(pn->lruvec_stats->state[i]); +#ifdef CONFIG_SMP + if (x < 0) + x = 0; +#endif + return x; } -static bool move_file(void) +unsigned long lruvec_page_state_local(struct lruvec *lruvec, + enum node_stat_item idx) { - return test_bit(MOVE_CHARGE_TYPE_FILE, &mc.immigrate_flags); -} + struct mem_cgroup_per_node *pn; + long x; + int i; -/* - * 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, -}; + if (mem_cgroup_disabled()) + return node_page_state(lruvec_pgdat(lruvec), idx); -/* for encoding cft->private value on file */ -enum res_type { - _MEM, - _MEMSWAP, - _OOM_TYPE, - _KMEM, -}; + i = memcg_stats_index(idx); + if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, idx)) + return 0; -#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) + pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec); + x = READ_ONCE(pn->lruvec_stats->state_local[i]); +#ifdef CONFIG_SMP + if (x < 0) + x = 0; +#endif + return x; +} -/* - * 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) +/* Subset of vm_event_item to report for memcg event stats */ +static const unsigned int memcg_vm_event_stat[] = { +#ifdef CONFIG_MEMCG_V1 + PGPGIN, + PGPGOUT, +#endif + PSWPIN, + PSWPOUT, + PGSCAN_KSWAPD, + PGSCAN_DIRECT, + PGSCAN_KHUGEPAGED, + PGSCAN_PROACTIVE, + PGSTEAL_KSWAPD, + PGSTEAL_DIRECT, + PGSTEAL_KHUGEPAGED, + PGSTEAL_PROACTIVE, + PGFAULT, + PGMAJFAULT, + PGREFILL, + PGACTIVATE, + PGDEACTIVATE, + PGLAZYFREE, + PGLAZYFREED, +#ifdef CONFIG_SWAP + SWPIN_ZERO, + SWPOUT_ZERO, +#endif +#ifdef CONFIG_ZSWAP + ZSWPIN, + ZSWPOUT, + ZSWPWB, +#endif +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + THP_FAULT_ALLOC, + THP_COLLAPSE_ALLOC, + THP_SWPOUT, + THP_SWPOUT_FALLBACK, +#endif +#ifdef CONFIG_NUMA_BALANCING + NUMA_PAGE_MIGRATE, + NUMA_PTE_UPDATES, + NUMA_HINT_FAULTS, +#endif +}; -/* - * 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); +#define NR_MEMCG_EVENTS ARRAY_SIZE(memcg_vm_event_stat) +static u8 mem_cgroup_events_index[NR_VM_EVENT_ITEMS] __read_mostly; -static inline -struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s) +static void init_memcg_events(void) { - return container_of(s, struct mem_cgroup, css); -} + u8 i; -/* Some nice accessors for the vmpressure. */ -struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg) -{ - if (!memcg) - memcg = root_mem_cgroup; - return &memcg->vmpressure; -} + BUILD_BUG_ON(NR_VM_EVENT_ITEMS >= U8_MAX); -struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr) -{ - return &container_of(vmpr, struct mem_cgroup, vmpressure)->css; -} + memset(mem_cgroup_events_index, U8_MAX, + sizeof(mem_cgroup_events_index)); -struct vmpressure *css_to_vmpressure(struct cgroup_subsys_state *css) -{ - return &mem_cgroup_from_css(css)->vmpressure; + for (i = 0; i < NR_MEMCG_EVENTS; ++i) + mem_cgroup_events_index[memcg_vm_event_stat[i]] = i; } -static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg) +static inline int memcg_events_index(enum vm_event_item idx) { - return (memcg == root_mem_cgroup); + return mem_cgroup_events_index[idx]; } -/* Writing them here to avoid exposing memcg's inner layout */ -#if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM) +struct memcg_vmstats_percpu { + /* Stats updates since the last flush */ + unsigned int stats_updates; -void sock_update_memcg(struct sock *sk) -{ - if (mem_cgroup_sockets_enabled) { - struct mem_cgroup *memcg; - struct cg_proto *cg_proto; + /* Cached pointers for fast iteration in memcg_rstat_updated() */ + struct memcg_vmstats_percpu __percpu *parent_pcpu; + struct memcg_vmstats *vmstats; - BUG_ON(!sk->sk_prot->proto_cgroup); + /* The above should fit a single cacheline for memcg_rstat_updated() */ - /* 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; - } + /* Local (CPU and cgroup) page state & events */ + long state[MEMCG_VMSTAT_SIZE]; + unsigned long events[NR_MEMCG_EVENTS]; - 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); + /* Delta calculation for lockless upward propagation */ + long state_prev[MEMCG_VMSTAT_SIZE]; + unsigned long events_prev[NR_MEMCG_EVENTS]; +} ____cacheline_aligned; -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 memcg_vmstats { + /* Aggregated (CPU and subtree) page state & events */ + long state[MEMCG_VMSTAT_SIZE]; + unsigned long events[NR_MEMCG_EVENTS]; -struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg) -{ - if (!memcg || mem_cgroup_is_root(memcg)) - return NULL; + /* Non-hierarchical (CPU aggregated) page state & events */ + long state_local[MEMCG_VMSTAT_SIZE]; + unsigned long events_local[NR_MEMCG_EVENTS]; - return &memcg->tcp_mem.cg_proto; -} -EXPORT_SYMBOL(tcp_proto_cgroup); + /* Pending child counts during tree propagation */ + long state_pending[MEMCG_VMSTAT_SIZE]; + unsigned long events_pending[NR_MEMCG_EVENTS]; -static void disarm_sock_keys(struct mem_cgroup *memcg) -{ - if (!memcg_proto_activated(&memcg->tcp_mem.cg_proto)) - return; - static_key_slow_dec(&memcg_socket_limit_enabled); -} -#else -static void disarm_sock_keys(struct mem_cgroup *memcg) -{ -} -#endif + /* Stats updates since the last flush */ + atomic_t stats_updates; +}; -#ifdef CONFIG_MEMCG_KMEM /* - * This will be the memcg's index in each cache's ->memcg_params->memcg_caches. - * There are two main reasons for not using the css_id for this: - * 1) 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. + * memcg and lruvec stats flushing * - * 2) In order not to violate the cgroup API, we would like to do all memory - * allocation in ->create(). At that point, we haven't yet allocated the - * css_id. Having a separate index prevents us from messing with the cgroup - * core for this + * Many codepaths leading to stats update or read are performance sensitive and + * adding stats flushing in such codepaths is not desirable. So, to optimize the + * flushing the kernel does: * - * 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. + * 1) Periodically and asynchronously flush the stats every 2 seconds to not let + * rstat update tree grow unbounded. * - * MAX_SIZE should be as large as the number of css_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 - * css_id space is not getting any smaller, and we don't have to necessarily - * increase ours as well if it increases. + * 2) Flush the stats synchronously on reader side only when there are more than + * (MEMCG_CHARGE_BATCH * nr_cpus) update events. Though this optimization + * will let stats be out of sync by atmost (MEMCG_CHARGE_BATCH * nr_cpus) but + * only for 2 seconds due to (1). */ -#define MEMCG_CACHES_MIN_SIZE 4 -#define MEMCG_CACHES_MAX_SIZE 65535 +static void flush_memcg_stats_dwork(struct work_struct *w); +static DECLARE_DEFERRABLE_WORK(stats_flush_dwork, flush_memcg_stats_dwork); +static u64 flush_last_time; -/* - * 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); +#define FLUSH_TIME (2UL*HZ) -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) +static bool memcg_vmstats_needs_flush(struct memcg_vmstats *vmstats) { + return atomic_read(&vmstats->stats_updates) > + MEMCG_CHARGE_BATCH * num_online_cpus(); } -#endif /* CONFIG_MEMCG_KMEM */ -static void disarm_static_keys(struct mem_cgroup *memcg) +static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val, + int cpu) { - disarm_sock_keys(memcg); - disarm_kmem_keys(memcg); -} + struct memcg_vmstats_percpu __percpu *statc_pcpu; + struct memcg_vmstats_percpu *statc; + unsigned int stats_updates; -static void drain_all_stock_async(struct mem_cgroup *memcg); + if (!val) + return; -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]; -} + css_rstat_updated(&memcg->css, cpu); + statc_pcpu = memcg->vmstats_percpu; + for (; statc_pcpu; statc_pcpu = statc->parent_pcpu) { + statc = this_cpu_ptr(statc_pcpu); + /* + * If @memcg is already flushable then all its ancestors are + * flushable as well and also there is no need to increase + * stats_updates. + */ + if (memcg_vmstats_needs_flush(statc->vmstats)) + break; -struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg) -{ - return &memcg->css; + stats_updates = this_cpu_add_return(statc_pcpu->stats_updates, + abs(val)); + if (stats_updates < MEMCG_CHARGE_BATCH) + continue; + + stats_updates = this_cpu_xchg(statc_pcpu->stats_updates, 0); + atomic_add(stats_updates, &statc->vmstats->stats_updates); + } } -static struct mem_cgroup_per_zone * -page_cgroup_zoneinfo(struct mem_cgroup *memcg, struct page *page) +static void __mem_cgroup_flush_stats(struct mem_cgroup *memcg, bool force) { - int nid = page_to_nid(page); - int zid = page_zonenum(page); + bool needs_flush = memcg_vmstats_needs_flush(memcg->vmstats); - return mem_cgroup_zoneinfo(memcg, nid, zid); -} + trace_memcg_flush_stats(memcg, atomic_read(&memcg->vmstats->stats_updates), + force, needs_flush); -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]; -} + if (!force && !needs_flush) + return; -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); + if (mem_cgroup_is_root(memcg)) + WRITE_ONCE(flush_last_time, jiffies_64); - return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; + css_rstat_flush(&memcg->css); } -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) +/* + * mem_cgroup_flush_stats - flush the stats of a memory cgroup subtree + * @memcg: root of the subtree to flush + * + * Flushing is serialized by the underlying global rstat lock. There is also a + * minimum amount of work to be done even if there are no stat updates to flush. + * Hence, we only flush the stats if the updates delta exceeds a threshold. This + * avoids unnecessary work and contention on the underlying lock. + */ +void mem_cgroup_flush_stats(struct mem_cgroup *memcg) { - 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) + if (mem_cgroup_disabled()) 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; -} + if (!memcg) + memcg = root_mem_cgroup; -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; + __mem_cgroup_flush_stats(memcg, false); } -static void -mem_cgroup_remove_exceeded(struct mem_cgroup *memcg, - struct mem_cgroup_per_zone *mz, - struct mem_cgroup_tree_per_zone *mctz) +void mem_cgroup_flush_stats_ratelimited(struct mem_cgroup *memcg) { - spin_lock(&mctz->lock); - __mem_cgroup_remove_exceeded(memcg, mz, mctz); - spin_unlock(&mctz->lock); + /* Only flush if the periodic flusher is one full cycle late */ + if (time_after64(jiffies_64, READ_ONCE(flush_last_time) + 2*FLUSH_TIME)) + mem_cgroup_flush_stats(memcg); } - -static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page) +static void flush_memcg_stats_dwork(struct work_struct *w) { - 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. + * Deliberately ignore memcg_vmstats_needs_flush() here so that flushing + * in latency-sensitive paths is as cheap as possible. */ - 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); - } - } + __mem_cgroup_flush_stats(root_mem_cgroup, true); + queue_delayed_work(system_unbound_wq, &stats_flush_dwork, FLUSH_TIME); } -static struct mem_cgroup_per_zone * -__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) +unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx) { - struct rb_node *rightmost = NULL; - struct mem_cgroup_per_zone *mz; + long x; + int i = memcg_stats_index(idx); -retry: - mz = NULL; - rightmost = rb_last(&mctz->rb_root); - if (!rightmost) - goto done; /* Nothing to reclaim from */ + if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, idx)) + return 0; - 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; + x = READ_ONCE(memcg->vmstats->state[i]); +#ifdef CONFIG_SMP + if (x < 0) + x = 0; +#endif + return x; } -static struct mem_cgroup_per_zone * -mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) +static int memcg_page_state_unit(int item); + +/* + * Normalize the value passed into memcg_rstat_updated() to be in pages. Round + * up non-zero sub-page updates to 1 page as zero page updates are ignored. + */ +static int memcg_state_val_in_pages(int idx, int val) { - struct mem_cgroup_per_zone *mz; + int unit = memcg_page_state_unit(idx); - spin_lock(&mctz->lock); - mz = __mem_cgroup_largest_soft_limit_node(mctz); - spin_unlock(&mctz->lock); - return mz; + if (!val || unit == PAGE_SIZE) + return val; + else + return max(val * unit / PAGE_SIZE, 1UL); } -/* - * 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. +/** + * mod_memcg_state - update cgroup memory statistics + * @memcg: the memory cgroup + * @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item + * @val: delta to add to the counter, can be negative */ -static long mem_cgroup_read_stat(struct mem_cgroup *memcg, - enum mem_cgroup_stat_index idx) +void mod_memcg_state(struct mem_cgroup *memcg, enum memcg_stat_item idx, + int val) { - long val = 0; + int i = memcg_stats_index(idx); 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; -} + if (mem_cgroup_disabled()) + return; -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); + if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, idx)) + return; + + cpu = get_cpu(); + + this_cpu_add(memcg->vmstats_percpu->state[i], val); + val = memcg_state_val_in_pages(idx, val); + memcg_rstat_updated(memcg, val, cpu); + trace_mod_memcg_state(memcg, idx, val); + + put_cpu(); } -static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg, - enum mem_cgroup_events_index idx) +#ifdef CONFIG_MEMCG_V1 +/* idx can be of type enum memcg_stat_item or node_stat_item. */ +unsigned long memcg_page_state_local(struct mem_cgroup *memcg, int idx) { - unsigned long val = 0; - int cpu; + long x; + int i = memcg_stats_index(idx); - 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); + if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, idx)) + return 0; + + x = READ_ONCE(memcg->vmstats->state_local[i]); +#ifdef CONFIG_SMP + if (x < 0) + x = 0; #endif - return val; + return x; } +#endif -static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, - struct page *page, - bool anon, int nr_pages) +static void mod_memcg_lruvec_state(struct lruvec *lruvec, + enum node_stat_item idx, + int val) { - preempt_disable(); + struct mem_cgroup_per_node *pn; + struct mem_cgroup *memcg; + int i = memcg_stats_index(idx); + int cpu; - /* - * 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 (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, idx)) + return; - if (PageTransHuge(page)) - __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], - nr_pages); + pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec); + memcg = pn->memcg; - /* 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 */ - } + cpu = get_cpu(); - __this_cpu_add(memcg->stat->nr_page_events, nr_pages); + /* Update memcg */ + this_cpu_add(memcg->vmstats_percpu->state[i], val); - preempt_enable(); + /* Update lruvec */ + this_cpu_add(pn->lruvec_stats_percpu->state[i], val); + + val = memcg_state_val_in_pages(idx, val); + memcg_rstat_updated(memcg, val, cpu); + trace_mod_memcg_lruvec_state(memcg, idx, val); + + put_cpu(); } -unsigned long -mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru) +/** + * mod_lruvec_state - update lruvec memory statistics + * @lruvec: the lruvec + * @idx: the stat item + * @val: delta to add to the counter, can be negative + * + * The lruvec is the intersection of the NUMA node and a cgroup. This + * function updates the all three counters that are affected by a + * change of state at this level: per-node, per-cgroup, per-lruvec. + */ +void mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx, + int val) { - struct mem_cgroup_per_zone *mz; + /* Update node */ + mod_node_page_state(lruvec_pgdat(lruvec), idx, val); - mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec); - return mz->lru_size[lru]; + /* Update memcg and lruvec */ + if (!mem_cgroup_disabled()) + mod_memcg_lruvec_state(lruvec, idx, val); } -static unsigned long -mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid, - unsigned int lru_mask) +void lruvec_stat_mod_folio(struct folio *folio, enum node_stat_item idx, + int val) { - struct mem_cgroup_per_zone *mz; - enum lru_list lru; - unsigned long ret = 0; - - mz = mem_cgroup_zoneinfo(memcg, nid, zid); + struct mem_cgroup *memcg; + pg_data_t *pgdat = folio_pgdat(folio); + struct lruvec *lruvec; - for_each_lru(lru) { - if (BIT(lru) & lru_mask) - ret += mz->lru_size[lru]; + rcu_read_lock(); + memcg = folio_memcg(folio); + /* Untracked pages have no memcg, no lruvec. Update only the node */ + if (!memcg) { + rcu_read_unlock(); + mod_node_page_state(pgdat, idx, val); + return; } - return ret; + + lruvec = mem_cgroup_lruvec(memcg, pgdat); + mod_lruvec_state(lruvec, idx, val); + rcu_read_unlock(); } +EXPORT_SYMBOL(lruvec_stat_mod_folio); -static unsigned long -mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg, - int nid, unsigned int lru_mask) +void mod_lruvec_kmem_state(void *p, enum node_stat_item idx, int val) { - u64 total = 0; - int zid; + pg_data_t *pgdat = page_pgdat(virt_to_page(p)); + struct mem_cgroup *memcg; + struct lruvec *lruvec; - for (zid = 0; zid < MAX_NR_ZONES; zid++) - total += mem_cgroup_zone_nr_lru_pages(memcg, - nid, zid, lru_mask); + rcu_read_lock(); + memcg = mem_cgroup_from_slab_obj(p); - return total; + /* + * Untracked pages have no memcg, no lruvec. Update only the + * node. If we reparent the slab objects to the root memcg, + * when we free the slab object, we need to update the per-memcg + * vmstats to keep it correct for the root memcg. + */ + if (!memcg) { + mod_node_page_state(pgdat, idx, val); + } else { + lruvec = mem_cgroup_lruvec(memcg, pgdat); + mod_lruvec_state(lruvec, idx, val); + } + rcu_read_unlock(); } -static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg, - unsigned int lru_mask) +/** + * count_memcg_events - account VM events in a cgroup + * @memcg: the memory cgroup + * @idx: the event item + * @count: the number of events that occurred + */ +void count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx, + unsigned long count) { - int nid; - u64 total = 0; + int i = memcg_events_index(idx); + int cpu; + + if (mem_cgroup_disabled()) + return; + + if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, idx)) + return; - for_each_node_state(nid, N_MEMORY) - total += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask); - return total; + cpu = get_cpu(); + + this_cpu_add(memcg->vmstats_percpu->events[i], count); + memcg_rstat_updated(memcg, count, cpu); + trace_count_memcg_events(memcg, idx, count); + + put_cpu(); } -static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, - enum mem_cgroup_events_target target) +unsigned long memcg_events(struct mem_cgroup *memcg, int event) { - unsigned long val, next; + int i = memcg_events_index(event); - 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; -} + if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, event)) + return 0; -/* - * 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(); + return READ_ONCE(memcg->vmstats->events[i]); } -struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) +#ifdef CONFIG_MEMCG_V1 +unsigned long memcg_events_local(struct mem_cgroup *memcg, int event) { - return mem_cgroup_from_css( - cgroup_subsys_state(cont, mem_cgroup_subsys_id)); + int i = memcg_events_index(event); + + if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, event)) + return 0; + + return READ_ONCE(memcg->vmstats->events_local[i]); } +#endif struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) { @@ -1051,125 +882,105 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) if (unlikely(!p)) return NULL; - return mem_cgroup_from_css(task_subsys_state(p, mem_cgroup_subsys_id)); + return mem_cgroup_from_css(task_css(p, memory_cgrp_id)); } +EXPORT_SYMBOL(mem_cgroup_from_task); -struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) +static __always_inline struct mem_cgroup *active_memcg(void) { - struct mem_cgroup *memcg = NULL; + if (!in_task()) + return this_cpu_read(int_active_memcg); + else + return current->active_memcg; +} - if (!mm) +/** + * get_mem_cgroup_from_mm: Obtain a reference on given mm_struct's memcg. + * @mm: mm from which memcg should be extracted. It can be NULL. + * + * Obtain a reference on mm->memcg and returns it if successful. If mm + * is NULL, then the memcg is chosen as follows: + * 1) The active memcg, if set. + * 2) current->mm->memcg, if available + * 3) root memcg + * If mem_cgroup is disabled, NULL is returned. + */ +struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) +{ + struct mem_cgroup *memcg; + + if (mem_cgroup_disabled()) return NULL; + /* - * Because we have no locks, mm->owner's may be being moved to other - * cgroup. We use css_tryget() here even if this looks - * pessimistic (rather than adding locks here). + * Page cache insertions can happen without an + * actual mm context, e.g. during disk probing + * on boot, loopback IO, acct() writes etc. + * + * No need to css_get on root memcg as the reference + * counting is disabled on the root level in the + * cgroup core. See CSS_NO_REF. */ + if (unlikely(!mm)) { + memcg = active_memcg(); + if (unlikely(memcg)) { + /* remote memcg must hold a ref */ + css_get(&memcg->css); + return memcg; + } + mm = current->mm; + if (unlikely(!mm)) + return root_mem_cgroup; + } + rcu_read_lock(); do { memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); if (unlikely(!memcg)) - break; + memcg = root_mem_cgroup; } while (!css_tryget(&memcg->css)); rcu_read_unlock(); return memcg; } +EXPORT_SYMBOL(get_mem_cgroup_from_mm); -/* - * 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 +/** + * get_mem_cgroup_from_current - Obtain a reference on current task's memcg. */ -static struct mem_cgroup *__mem_cgroup_iter_next(struct mem_cgroup *root, - struct mem_cgroup *last_visited) +struct mem_cgroup *get_mem_cgroup_from_current(void) { - struct cgroup *prev_cgroup, *next_cgroup; - - /* - * Root is not visited by cgroup iterators so it needs an - * explicit visit. - */ - if (!last_visited) - return root; + struct mem_cgroup *memcg; - prev_cgroup = (last_visited == root) ? NULL - : last_visited->css.cgroup; -skip_node: - next_cgroup = cgroup_next_descendant_pre( - prev_cgroup, root->css.cgroup); + if (mem_cgroup_disabled()) + return NULL; - /* - * 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. - */ - if (next_cgroup) { - struct mem_cgroup *mem = mem_cgroup_from_cont( - next_cgroup); - if (css_tryget(&mem->css)) - return mem; - else { - prev_cgroup = next_cgroup; - goto skip_node; - } +again: + rcu_read_lock(); + memcg = mem_cgroup_from_task(current); + if (!css_tryget(&memcg->css)) { + rcu_read_unlock(); + goto again; } - - return NULL; + rcu_read_unlock(); + return memcg; } -static void mem_cgroup_iter_invalidate(struct mem_cgroup *root) +/** + * get_mem_cgroup_from_folio - Obtain a reference on a given folio's memcg. + * @folio: folio from which memcg should be extracted. + */ +struct mem_cgroup *get_mem_cgroup_from_folio(struct folio *folio) { - /* - * 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); -} + struct mem_cgroup *memcg = folio_memcg(folio); -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; - if (position && !css_tryget(&position->css)) - position = NULL; - } - return position; -} + if (mem_cgroup_disabled()) + return NULL; -static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter *iter, - struct mem_cgroup *last_visited, - struct mem_cgroup *new_position, - int sequence) -{ - if (last_visited) - 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; + rcu_read_lock(); + if (!memcg || WARN_ON_ONCE(!css_tryget(&memcg->css))) + memcg = root_mem_cgroup; + rcu_read_unlock(); + return memcg; } /** @@ -1185,16 +996,18 @@ static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter *iter, * 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. + * Reclaimers can specify a node in @reclaim to divide up the memcgs + * in the hierarchy among all concurrent reclaimers operating on the + * same node. */ 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; + struct mem_cgroup_reclaim_iter *iter; + struct cgroup_subsys_state *css; + struct mem_cgroup *pos; + struct mem_cgroup *next; if (mem_cgroup_disabled()) return NULL; @@ -1202,56 +1015,76 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, if (!root) root = root_mem_cgroup; - if (prev && !reclaim) - last_visited = prev; + rcu_read_lock(); +restart: + next = NULL; + + if (reclaim) { + int gen; + int nid = reclaim->pgdat->node_id; - if (!root->use_hierarchy && root != root_mem_cgroup) { - if (prev) - goto out_css_put; - return root; - } + iter = &root->nodeinfo[nid]->iter; + gen = atomic_read(&iter->generation); - 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; - } + /* + * On start, join the current reclaim iteration cycle. + * Exit when a concurrent walker completes it. + */ + if (!prev) + reclaim->generation = gen; + else if (reclaim->generation != gen) + goto out_unlock; - last_visited = mem_cgroup_iter_load(iter, root, &seq); - } + pos = READ_ONCE(iter->position); + } else + pos = prev; - memcg = __mem_cgroup_iter_next(root, last_visited); + css = pos ? &pos->css : NULL; - if (reclaim) { - mem_cgroup_iter_update(iter, last_visited, memcg, seq); + while ((css = css_next_descendant_pre(css, &root->css))) { + /* + * Verify the css and acquire a reference. The root + * is provided by the caller, so we know it's alive + * and kicking, and don't take an extra reference. + */ + if (css == &root->css || css_tryget(css)) + break; + } + + next = mem_cgroup_from_css(css); - if (!memcg) - iter->generation++; - else if (!prev && memcg) - reclaim->generation = iter->generation; + if (reclaim) { + /* + * The position could have already been updated by a competing + * thread, so check that the value hasn't changed since we read + * it to avoid reclaiming from the same cgroup twice. + */ + if (cmpxchg(&iter->position, pos, next) != pos) { + if (css && css != &root->css) + css_put(css); + goto restart; } - if (prev && !memcg) - goto out_unlock; + if (!next) { + atomic_inc(&iter->generation); + + /* + * Reclaimers share the hierarchy walk, and a + * new one might jump in right at the end of + * the hierarchy - make sure they see at least + * one group and restart from the beginning. + */ + if (!prev) + goto restart; + } } + out_unlock: rcu_read_unlock(); -out_css_put: if (prev && prev != root) css_put(&prev->css); - return memcg; + return next; } /** @@ -1268,134 +1101,161 @@ void mem_cgroup_iter_break(struct mem_cgroup *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)) +static void __invalidate_reclaim_iterators(struct mem_cgroup *from, + struct mem_cgroup *dead_memcg) +{ + struct mem_cgroup_reclaim_iter *iter; + struct mem_cgroup_per_node *mz; + int nid; -#define for_each_mem_cgroup(iter) \ - for (iter = mem_cgroup_iter(NULL, NULL, NULL); \ - iter != NULL; \ - iter = mem_cgroup_iter(NULL, iter, NULL)) + for_each_node(nid) { + mz = from->nodeinfo[nid]; + iter = &mz->iter; + cmpxchg(&iter->position, dead_memcg, NULL); + } +} -void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx) +static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg) { - struct mem_cgroup *memcg; + struct mem_cgroup *memcg = dead_memcg; + struct mem_cgroup *last; - rcu_read_lock(); - memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); - if (unlikely(!memcg)) - goto out; + do { + __invalidate_reclaim_iterators(memcg, dead_memcg); + last = memcg; + } while ((memcg = parent_mem_cgroup(memcg))); - 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(); + /* + * When cgroup1 non-hierarchy mode is used, + * parent_mem_cgroup() does not walk all the way up to the + * cgroup root (root_mem_cgroup). So we have to handle + * dead_memcg from cgroup root separately. + */ + if (!mem_cgroup_is_root(last)) + __invalidate_reclaim_iterators(root_mem_cgroup, + dead_memcg); } -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 + * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy + * @memcg: hierarchy root + * @fn: function to call for each task + * @arg: argument passed to @fn + * + * This function iterates over tasks attached to @memcg or to any of its + * descendants and calls @fn for each task. If @fn returns a non-zero + * value, the function breaks the iteration loop. Otherwise, it will iterate + * over all tasks and return 0. * - * 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. + * This function must not be called for the root memory cgroup. */ -struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone, - struct mem_cgroup *memcg) +void mem_cgroup_scan_tasks(struct mem_cgroup *memcg, + int (*fn)(struct task_struct *, void *), void *arg) { - struct mem_cgroup_per_zone *mz; - struct lruvec *lruvec; + struct mem_cgroup *iter; + int ret = 0; - if (mem_cgroup_disabled()) { - lruvec = &zone->lruvec; - goto out; + BUG_ON(mem_cgroup_is_root(memcg)); + + for_each_mem_cgroup_tree(iter, memcg) { + struct css_task_iter it; + struct task_struct *task; + + css_task_iter_start(&iter->css, CSS_TASK_ITER_PROCS, &it); + while (!ret && (task = css_task_iter_next(&it))) { + ret = fn(task, arg); + /* Avoid potential softlockup warning */ + cond_resched(); + } + css_task_iter_end(&it); + if (ret) { + mem_cgroup_iter_break(memcg, iter); + break; + } } +} - 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; +#ifdef CONFIG_DEBUG_VM +void lruvec_memcg_debug(struct lruvec *lruvec, struct folio *folio) +{ + struct mem_cgroup *memcg; + + if (mem_cgroup_disabled()) + return; + + memcg = folio_memcg(folio); + + if (!memcg) + VM_BUG_ON_FOLIO(!mem_cgroup_is_root(lruvec_memcg(lruvec)), folio); + else + VM_BUG_ON_FOLIO(lruvec_memcg(lruvec) != memcg, folio); } +#endif -/* - * 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. +/** + * folio_lruvec_lock - Lock the lruvec for a folio. + * @folio: Pointer to the folio. * - * 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. + * These functions are safe to use under any of the following conditions: + * - folio locked + * - folio_test_lru false + * - folio frozen (refcount of 0) + * + * Return: The lruvec this folio is on with its lock held. */ +struct lruvec *folio_lruvec_lock(struct folio *folio) +{ + struct lruvec *lruvec = folio_lruvec(folio); + + spin_lock(&lruvec->lru_lock); + lruvec_memcg_debug(lruvec, folio); + + return lruvec; +} /** - * mem_cgroup_page_lruvec - return lruvec for adding an lru page - * @page: the page - * @zone: zone of the page + * folio_lruvec_lock_irq - Lock the lruvec for a folio. + * @folio: Pointer to the folio. + * + * These functions are safe to use under any of the following conditions: + * - folio locked + * - folio_test_lru false + * - folio frozen (refcount of 0) + * + * Return: The lruvec this folio is on with its lock held and interrupts + * disabled. */ -struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone) +struct lruvec *folio_lruvec_lock_irq(struct folio *folio) { - struct mem_cgroup_per_zone *mz; - struct mem_cgroup *memcg; - struct page_cgroup *pc; - struct lruvec *lruvec; + struct lruvec *lruvec = folio_lruvec(folio); - if (mem_cgroup_disabled()) { - lruvec = &zone->lruvec; - goto out; - } + spin_lock_irq(&lruvec->lru_lock); + lruvec_memcg_debug(lruvec, folio); - pc = lookup_page_cgroup(page); - memcg = pc->mem_cgroup; + return lruvec; +} - /* - * 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; +/** + * folio_lruvec_lock_irqsave - Lock the lruvec for a folio. + * @folio: Pointer to the folio. + * @flags: Pointer to irqsave flags. + * + * These functions are safe to use under any of the following conditions: + * - folio locked + * - folio_test_lru false + * - folio frozen (refcount of 0) + * + * Return: The lruvec this folio is on with its lock held and interrupts + * disabled. + */ +struct lruvec *folio_lruvec_lock_irqsave(struct folio *folio, + unsigned long *flags) +{ + struct lruvec *lruvec = folio_lruvec(folio); + + spin_lock_irqsave(&lruvec->lru_lock, *flags); + lruvec_memcg_debug(lruvec, folio); - 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; } @@ -1403,109 +1263,40 @@ out: * 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 + * @zid: zone id of the accounted pages * @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. + * This function must be called under lru_lock, just before a page is added + * to or just after a page is removed from an lru list. */ void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru, - int nr_pages) + int zid, int nr_pages) { - struct mem_cgroup_per_zone *mz; + struct mem_cgroup_per_node *mz; unsigned long *lru_size; + long 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 css_is_ancestor(&memcg->css, &root_memcg->css); -} - -static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, - struct mem_cgroup *memcg) -{ - bool ret; + mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec); + lru_size = &mz->lru_zone_size[zid][lru]; - rcu_read_lock(); - ret = __mem_cgroup_same_or_subtree(root_memcg, memcg); - rcu_read_unlock(); - return ret; -} + if (nr_pages < 0) + *lru_size += nr_pages; -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 = try_get_mem_cgroup_from_mm(p->mm); - task_unlock(p); - } else { - /* - * All threads may have already detached their mm's, but the oom - * killer still needs to detect if they have already been oom - * killed to prevent needlessly killing additional tasks. - */ - rcu_read_lock(); - curr = mem_cgroup_from_task(task); - if (curr) - css_get(&curr->css); - rcu_read_unlock(); + size = *lru_size; + if (WARN_ONCE(size < 0, + "%s(%p, %d, %d): lru_size %ld\n", + __func__, lruvec, lru, nr_pages, size)) { + VM_BUG_ON(1); + *lru_size = 0; } - if (!curr) - return false; - /* - * 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; + if (nr_pages > 0) + *lru_size += nr_pages; } -#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 @@ -1515,1085 +1306,1100 @@ int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec) */ static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg) { - unsigned long long margin; + unsigned long margin = 0; + unsigned long count; + unsigned long limit; - margin = res_counter_margin(&memcg->res); - if (do_swap_account) - margin = min(margin, res_counter_margin(&memcg->memsw)); - return margin >> PAGE_SHIFT; -} + count = page_counter_read(&memcg->memory); + limit = READ_ONCE(memcg->memory.max); + if (count < limit) + margin = limit - count; -int mem_cgroup_swappiness(struct mem_cgroup *memcg) -{ - struct cgroup *cgrp = memcg->css.cgroup; - - /* root ? */ - if (cgrp->parent == NULL) - return vm_swappiness; + if (do_memsw_account()) { + count = page_counter_read(&memcg->memsw); + limit = READ_ONCE(memcg->memsw.max); + if (count < limit) + margin = min(margin, limit - count); + else + margin = 0; + } - return memcg->swappiness; + return margin; } -/* - * 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. - */ +struct memory_stat { + const char *name; + unsigned int idx; +}; + +static const struct memory_stat memory_stats[] = { + { "anon", NR_ANON_MAPPED }, + { "file", NR_FILE_PAGES }, + { "kernel", MEMCG_KMEM }, + { "kernel_stack", NR_KERNEL_STACK_KB }, + { "pagetables", NR_PAGETABLE }, + { "sec_pagetables", NR_SECONDARY_PAGETABLE }, + { "percpu", MEMCG_PERCPU_B }, + { "sock", MEMCG_SOCK }, + { "vmalloc", MEMCG_VMALLOC }, + { "shmem", NR_SHMEM }, +#ifdef CONFIG_ZSWAP + { "zswap", MEMCG_ZSWAP_B }, + { "zswapped", MEMCG_ZSWAPPED }, +#endif + { "file_mapped", NR_FILE_MAPPED }, + { "file_dirty", NR_FILE_DIRTY }, + { "file_writeback", NR_WRITEBACK }, +#ifdef CONFIG_SWAP + { "swapcached", NR_SWAPCACHE }, +#endif +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + { "anon_thp", NR_ANON_THPS }, + { "file_thp", NR_FILE_THPS }, + { "shmem_thp", NR_SHMEM_THPS }, +#endif + { "inactive_anon", NR_INACTIVE_ANON }, + { "active_anon", NR_ACTIVE_ANON }, + { "inactive_file", NR_INACTIVE_FILE }, + { "active_file", NR_ACTIVE_FILE }, + { "unevictable", NR_UNEVICTABLE }, + { "slab_reclaimable", NR_SLAB_RECLAIMABLE_B }, + { "slab_unreclaimable", NR_SLAB_UNRECLAIMABLE_B }, +#ifdef CONFIG_HUGETLB_PAGE + { "hugetlb", NR_HUGETLB }, +#endif -/* for quick checking without looking up memcg */ -atomic_t memcg_moving __read_mostly; + /* The memory events */ + { "workingset_refault_anon", WORKINGSET_REFAULT_ANON }, + { "workingset_refault_file", WORKINGSET_REFAULT_FILE }, + { "workingset_activate_anon", WORKINGSET_ACTIVATE_ANON }, + { "workingset_activate_file", WORKINGSET_ACTIVATE_FILE }, + { "workingset_restore_anon", WORKINGSET_RESTORE_ANON }, + { "workingset_restore_file", WORKINGSET_RESTORE_FILE }, + { "workingset_nodereclaim", WORKINGSET_NODERECLAIM }, + + { "pgdemote_kswapd", PGDEMOTE_KSWAPD }, + { "pgdemote_direct", PGDEMOTE_DIRECT }, + { "pgdemote_khugepaged", PGDEMOTE_KHUGEPAGED }, + { "pgdemote_proactive", PGDEMOTE_PROACTIVE }, +#ifdef CONFIG_NUMA_BALANCING + { "pgpromote_success", PGPROMOTE_SUCCESS }, +#endif +}; -static void mem_cgroup_start_move(struct mem_cgroup *memcg) +/* The actual unit of the state item, not the same as the output unit */ +static int memcg_page_state_unit(int item) { - atomic_inc(&memcg_moving); - atomic_inc(&memcg->moving_account); - synchronize_rcu(); + switch (item) { + case MEMCG_PERCPU_B: + case MEMCG_ZSWAP_B: + case NR_SLAB_RECLAIMABLE_B: + case NR_SLAB_UNRECLAIMABLE_B: + return 1; + case NR_KERNEL_STACK_KB: + return SZ_1K; + default: + return PAGE_SIZE; + } } -static void mem_cgroup_end_move(struct mem_cgroup *memcg) +/* Translate stat items to the correct unit for memory.stat output */ +static int memcg_page_state_output_unit(int item) { /* - * Now, mem_cgroup_clear_mc() may call this function with NULL. - * We check NULL in callee rather than caller. + * Workingset state is actually in pages, but we export it to userspace + * as a scalar count of events, so special case it here. + * + * Demotion and promotion activities are exported in pages, consistent + * with their global counterparts. */ - if (memcg) { - atomic_dec(&memcg_moving); - atomic_dec(&memcg->moving_account); + switch (item) { + case WORKINGSET_REFAULT_ANON: + case WORKINGSET_REFAULT_FILE: + case WORKINGSET_ACTIVATE_ANON: + case WORKINGSET_ACTIVATE_FILE: + case WORKINGSET_RESTORE_ANON: + case WORKINGSET_RESTORE_FILE: + case WORKINGSET_NODERECLAIM: + case PGDEMOTE_KSWAPD: + case PGDEMOTE_DIRECT: + case PGDEMOTE_KHUGEPAGED: + case PGDEMOTE_PROACTIVE: +#ifdef CONFIG_NUMA_BALANCING + case PGPROMOTE_SUCCESS: +#endif + return 1; + default: + return memcg_page_state_unit(item); } } -/* - * 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". - */ +unsigned long memcg_page_state_output(struct mem_cgroup *memcg, int item) +{ + return memcg_page_state(memcg, item) * + memcg_page_state_output_unit(item); +} -static bool mem_cgroup_stolen(struct mem_cgroup *memcg) +#ifdef CONFIG_MEMCG_V1 +unsigned long memcg_page_state_local_output(struct mem_cgroup *memcg, int item) { - VM_BUG_ON(!rcu_read_lock_held()); - return atomic_read(&memcg->moving_account) > 0; + return memcg_page_state_local(memcg, item) * + memcg_page_state_output_unit(item); } +#endif -static bool mem_cgroup_under_move(struct mem_cgroup *memcg) +#ifdef CONFIG_HUGETLB_PAGE +static bool memcg_accounts_hugetlb(void) { - struct mem_cgroup *from; - struct mem_cgroup *to; - bool ret = false; + return cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING; +} +#else /* CONFIG_HUGETLB_PAGE */ +static bool memcg_accounts_hugetlb(void) +{ + return false; +} +#endif /* CONFIG_HUGETLB_PAGE */ + +static void memcg_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) +{ + int i; + /* - * Unlike task_move routines, we access mc.to, mc.from not under - * mutual exclusion by cgroup_mutex. Here, we take spinlock instead. + * Provide statistics on the state of the memory subsystem as + * well as cumulative event counters that show past behavior. + * + * This list is ordered following a combination of these gradients: + * 1) generic big picture -> specifics and details + * 2) reflecting userspace activity -> reflecting kernel heuristics + * + * Current memory state: */ - spin_lock(&mc.lock); - from = mc.from; - to = mc.to; - if (!from) - goto unlock; + mem_cgroup_flush_stats(memcg); - ret = mem_cgroup_same_or_subtree(memcg, from) - || mem_cgroup_same_or_subtree(memcg, to); -unlock: - spin_unlock(&mc.lock); - return ret; -} + for (i = 0; i < ARRAY_SIZE(memory_stats); i++) { + u64 size; -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; +#ifdef CONFIG_HUGETLB_PAGE + if (unlikely(memory_stats[i].idx == NR_HUGETLB) && + !memcg_accounts_hugetlb()) + continue; +#endif + size = memcg_page_state_output(memcg, memory_stats[i].idx); + seq_buf_printf(s, "%s %llu\n", memory_stats[i].name, size); + + if (unlikely(memory_stats[i].idx == NR_SLAB_UNRECLAIMABLE_B)) { + size += memcg_page_state_output(memcg, + NR_SLAB_RECLAIMABLE_B); + seq_buf_printf(s, "slab %llu\n", size); } } - 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); + /* Accumulated memory events */ + seq_buf_printf(s, "pgscan %lu\n", + memcg_events(memcg, PGSCAN_KSWAPD) + + memcg_events(memcg, PGSCAN_DIRECT) + + memcg_events(memcg, PGSCAN_PROACTIVE) + + memcg_events(memcg, PGSCAN_KHUGEPAGED)); + seq_buf_printf(s, "pgsteal %lu\n", + memcg_events(memcg, PGSTEAL_KSWAPD) + + memcg_events(memcg, PGSTEAL_DIRECT) + + memcg_events(memcg, PGSTEAL_PROACTIVE) + + memcg_events(memcg, PGSTEAL_KHUGEPAGED)); + + for (i = 0; i < ARRAY_SIZE(memcg_vm_event_stat); i++) { +#ifdef CONFIG_MEMCG_V1 + if (memcg_vm_event_stat[i] == PGPGIN || + memcg_vm_event_stat[i] == PGPGOUT) + continue; +#endif + seq_buf_printf(s, "%s %lu\n", + vm_event_name(memcg_vm_event_stat[i]), + memcg_events(memcg, memcg_vm_event_stat[i])); + } } -static void move_unlock_mem_cgroup(struct mem_cgroup *memcg, - unsigned long *flags) +static void memory_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) { - spin_unlock_irqrestore(&memcg->move_lock, *flags); + if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) + memcg_stat_format(memcg, s); + else + memcg1_stat_format(memcg, s); + if (seq_buf_has_overflowed(s)) + pr_warn("%s: Warning, stat buffer overflow, please report\n", __func__); } -#define K(x) ((x) << (PAGE_SHIFT-10)) /** - * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller. + * mem_cgroup_print_oom_context: 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) +void mem_cgroup_print_oom_context(struct mem_cgroup *memcg, struct task_struct *p) { - struct cgroup *task_cgrp; - struct cgroup *mem_cgrp; - /* - * Need a buffer in BSS, can't rely on allocations. The code relies - * on the assumption that OOM is serialized for memory controller. - * If this assumption is broken, revisit this code. - */ - static char memcg_name[PATH_MAX]; - int ret; - struct mem_cgroup *iter; - unsigned int i; - - if (!p) - return; - rcu_read_lock(); - mem_cgrp = memcg->css.cgroup; - task_cgrp = task_cgroup(p, mem_cgroup_subsys_id); - - ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX); - if (ret < 0) { - /* - * Unfortunately, we are unable to convert to a useful name - * But we'll still print out the usage information - */ - rcu_read_unlock(); - goto done; - } - rcu_read_unlock(); - - pr_info("Task in %s killed", memcg_name); - - rcu_read_lock(); - ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX); - if (ret < 0) { - rcu_read_unlock(); - goto done; + if (memcg) { + pr_cont(",oom_memcg="); + pr_cont_cgroup_path(memcg->css.cgroup); + } else + pr_cont(",global_oom"); + if (p) { + pr_cont(",task_memcg="); + pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id)); } rcu_read_unlock(); - - /* - * Continues from above, so we don't need an KERN_ level - */ - pr_cont(" as a result of limit of %s\n", memcg_name); -done: - - 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"); - - rcu_read_lock(); - ret = cgroup_path(iter->css.cgroup, memcg_name, PATH_MAX); - if (!ret) - pr_cont(" for %s", memcg_name); - rcu_read_unlock(); - 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"); - } } -/* - * This function returns the number of memcg under hierarchy tree. Returns - * 1(self count) if no children. +/** + * mem_cgroup_print_oom_meminfo: Print OOM memory information relevant to + * memory controller. + * @memcg: The memory cgroup that went over limit */ -static int mem_cgroup_count_children(struct mem_cgroup *memcg) +void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg) { - int num = 0; - struct mem_cgroup *iter; + /* Use static buffer, for the caller is holding oom_lock. */ + static char buf[SEQ_BUF_SIZE]; + struct seq_buf s; + unsigned long memory_failcnt; + + lockdep_assert_held(&oom_lock); + + if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) + memory_failcnt = atomic_long_read(&memcg->memory_events[MEMCG_MAX]); + else + memory_failcnt = memcg->memory.failcnt; + + pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n", + K((u64)page_counter_read(&memcg->memory)), + K((u64)READ_ONCE(memcg->memory.max)), memory_failcnt); + if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) + pr_info("swap: usage %llukB, limit %llukB, failcnt %lu\n", + K((u64)page_counter_read(&memcg->swap)), + K((u64)READ_ONCE(memcg->swap.max)), + atomic_long_read(&memcg->memory_events[MEMCG_SWAP_MAX])); +#ifdef CONFIG_MEMCG_V1 + else { + pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n", + K((u64)page_counter_read(&memcg->memsw)), + K((u64)memcg->memsw.max), memcg->memsw.failcnt); + pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n", + K((u64)page_counter_read(&memcg->kmem)), + K((u64)memcg->kmem.max), memcg->kmem.failcnt); + } +#endif - for_each_mem_cgroup_tree(iter, memcg) - num++; - return num; + pr_info("Memory cgroup stats for "); + pr_cont_cgroup_path(memcg->css.cgroup); + pr_cont(":"); + seq_buf_init(&s, buf, SEQ_BUF_SIZE); + memory_stat_format(memcg, &s); + seq_buf_do_printk(&s, KERN_INFO); } /* * Return the memory (and swap, if configured) limit for a memcg. */ -static u64 mem_cgroup_get_limit(struct mem_cgroup *memcg) +unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg) { - u64 limit; + unsigned long max = READ_ONCE(memcg->memory.max); - limit = res_counter_read_u64(&memcg->res, RES_LIMIT); + if (do_memsw_account()) { + if (mem_cgroup_swappiness(memcg)) { + /* Calculate swap excess capacity from memsw limit */ + unsigned long swap = READ_ONCE(memcg->memsw.max) - max; - /* - * 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); + max += min(swap, (unsigned long)total_swap_pages); + } + } else { + if (mem_cgroup_swappiness(memcg)) + max += min(READ_ONCE(memcg->swap.max), + (unsigned long)total_swap_pages); } + return max; +} - return limit; +unsigned long mem_cgroup_size(struct mem_cgroup *memcg) +{ + return page_counter_read(&memcg->memory); } -static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, - int order) +void __memcg_memory_event(struct mem_cgroup *memcg, + enum memcg_memory_event event, bool allow_spinning) { - struct mem_cgroup *iter; - unsigned long chosen_points = 0; - unsigned long totalpages; - unsigned int points = 0; - struct task_struct *chosen = NULL; + bool swap_event = event == MEMCG_SWAP_HIGH || event == MEMCG_SWAP_MAX || + event == MEMCG_SWAP_FAIL; - /* - * 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; - } + /* For now only MEMCG_MAX can happen with !allow_spinning context. */ + VM_WARN_ON_ONCE(!allow_spinning && event != MEMCG_MAX); - 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 cgroup *cgroup = iter->css.cgroup; - struct cgroup_iter it; - struct task_struct *task; + atomic_long_inc(&memcg->memory_events_local[event]); + if (!swap_event && allow_spinning) + cgroup_file_notify(&memcg->events_local_file); - cgroup_iter_start(cgroup, &it); - while ((task = cgroup_iter_next(cgroup, &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: - cgroup_iter_end(cgroup, &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 > chosen_points) { - if (chosen) - put_task_struct(chosen); - chosen = task; - chosen_points = points; - get_task_struct(chosen); - } + do { + atomic_long_inc(&memcg->memory_events[event]); + if (allow_spinning) { + if (swap_event) + cgroup_file_notify(&memcg->swap_events_file); + else + cgroup_file_notify(&memcg->events_file); } - cgroup_iter_end(cgroup, &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)) + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) break; - if (mem_cgroup_margin(memcg)) + if (cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_LOCAL_EVENTS) break; - /* - * If nothing was reclaimed after two attempts, there - * may be no reclaimable pages in this hierarchy. - */ - if (loop && !total) - break; - } - return total; + } while ((memcg = parent_mem_cgroup(memcg)) && + !mem_cgroup_is_root(memcg)); } +EXPORT_SYMBOL_GPL(__memcg_memory_event); -/** - * 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) +static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, + int order) { - 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)) + struct oom_control oc = { + .zonelist = NULL, + .nodemask = NULL, + .memcg = memcg, + .gfp_mask = gfp_mask, + .order = order, + }; + bool ret = true; + + if (mutex_lock_killable(&oom_lock)) return true; - return false; + if (mem_cgroup_margin(memcg) >= (1 << order)) + goto unlock; + + /* + * A few threads which were not waiting at mutex_lock_killable() can + * fail to bail out. Therefore, check again after holding oom_lock. + */ + ret = out_of_memory(&oc); + +unlock: + mutex_unlock(&oom_lock); + return ret; } -#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. - * + * Returns true if successfully killed one or more processes. Though in some + * corner cases it can return true even without killing any process. */ -static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg) +static bool mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order) { - 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; + bool locked, ret; - /* make a nodemask where this memcg uses memory from */ - memcg->scan_nodes = node_states[N_MEMORY]; + if (order > PAGE_ALLOC_COSTLY_ORDER) + return false; - for_each_node_mask(nid, node_states[N_MEMORY]) { + memcg_memory_event(memcg, MEMCG_OOM); - if (!test_mem_cgroup_node_reclaimable(memcg, nid, false)) - node_clear(nid, memcg->scan_nodes); - } + if (!memcg1_oom_prepare(memcg, &locked)) + return false; + + ret = mem_cgroup_out_of_memory(memcg, mask, order); + + memcg1_oom_finish(memcg, locked); - atomic_set(&memcg->numainfo_events, 0); - atomic_set(&memcg->numainfo_updating, 0); + return ret; } -/* - * 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. +/** + * mem_cgroup_get_oom_group - get a memory cgroup to clean up after OOM + * @victim: task to be killed by the OOM killer + * @oom_domain: memcg in case of memcg OOM, NULL in case of system-wide OOM * - * 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. + * Returns a pointer to a memory cgroup, which has to be cleaned up + * by killing all belonging OOM-killable tasks. * - * Now, we use round-robin. Better algorithm is welcomed. + * Caller has to call mem_cgroup_put() on the returned non-NULL memcg. */ -int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) +struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim, + struct mem_cgroup *oom_domain) { - int node; + struct mem_cgroup *oom_group = NULL; + struct mem_cgroup *memcg; - mem_cgroup_may_update_nodemask(memcg); - node = memcg->last_scanned_node; + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) + return NULL; - 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(); + if (!oom_domain) + oom_domain = root_mem_cgroup; - memcg->last_scanned_node = node; - return node; -} + rcu_read_lock(); -/* - * 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; + memcg = mem_cgroup_from_task(victim); + if (mem_cgroup_is_root(memcg)) + goto out; /* - * quick check...making use of scan_node. - * We can skip unused nodes. + * If the victim task has been asynchronously moved to a different + * memory cgroup, we might end up killing tasks outside oom_domain. + * In this case it's better to ignore memory.group.oom. */ - if (!nodes_empty(memcg->scan_nodes)) { - for (nid = first_node(memcg->scan_nodes); - nid < MAX_NUMNODES; - nid = next_node(nid, memcg->scan_nodes)) { + if (unlikely(!mem_cgroup_is_descendant(memcg, oom_domain))) + goto out; - if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap)) - return true; - } - } /* - * Check rest of nodes. + * Traverse the memory cgroup hierarchy from the victim task's + * cgroup up to the OOMing cgroup (or root) to find the + * highest-level memory cgroup with oom.group set. */ - 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; + for (; memcg; memcg = parent_mem_cgroup(memcg)) { + if (READ_ONCE(memcg->oom_group)) + oom_group = memcg; + + if (memcg == oom_domain) + break; } - return false; -} -#else -int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) -{ - return 0; + if (oom_group) + css_get(&oom_group->css); +out: + rcu_read_unlock(); + + return oom_group; } -static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap) +void mem_cgroup_print_oom_group(struct mem_cgroup *memcg) { - return test_mem_cgroup_node_reclaimable(memcg, 0, noswap); + pr_info("Tasks in "); + pr_cont_cgroup_path(memcg->css.cgroup); + pr_cont(" are going to be killed due to memory.oom.group set\n"); } -#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, - }; +/* + * The value of NR_MEMCG_STOCK is selected to keep the cached memcgs and their + * nr_pages in a single cacheline. This may change in future. + */ +#define NR_MEMCG_STOCK 7 +#define FLUSHING_CACHED_CHARGE 0 +struct memcg_stock_pcp { + local_trylock_t lock; + uint8_t nr_pages[NR_MEMCG_STOCK]; + struct mem_cgroup *cached[NR_MEMCG_STOCK]; - 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; -} + struct work_struct work; + unsigned long flags; +}; -/* - * Check OOM-Killer is already running under our hierarchy. - * If someone is running, return false. - * Has to be called with memcg_oom_lock +static DEFINE_PER_CPU_ALIGNED(struct memcg_stock_pcp, memcg_stock) = { + .lock = INIT_LOCAL_TRYLOCK(lock), +}; + +struct obj_stock_pcp { + local_trylock_t lock; + unsigned int nr_bytes; + struct obj_cgroup *cached_objcg; + struct pglist_data *cached_pgdat; + int nr_slab_reclaimable_b; + int nr_slab_unreclaimable_b; + + struct work_struct work; + unsigned long flags; +}; + +static DEFINE_PER_CPU_ALIGNED(struct obj_stock_pcp, obj_stock) = { + .lock = INIT_LOCAL_TRYLOCK(lock), +}; + +static DEFINE_MUTEX(percpu_charge_mutex); + +static void drain_obj_stock(struct obj_stock_pcp *stock); +static bool obj_stock_flush_required(struct obj_stock_pcp *stock, + struct mem_cgroup *root_memcg); + +/** + * consume_stock: Try to consume stocked charge on this cpu. + * @memcg: memcg to consume from. + * @nr_pages: how many pages to charge. + * + * Consume the cached charge if enough nr_pages are present otherwise return + * failure. Also return failure for charge request larger than + * MEMCG_CHARGE_BATCH or if the local lock is already taken. + * + * returns true if successful, false otherwise. */ -static bool mem_cgroup_oom_lock(struct mem_cgroup *memcg) +static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages) { - struct mem_cgroup *iter, *failed = NULL; + struct memcg_stock_pcp *stock; + uint8_t stock_pages; + bool ret = false; + int i; - 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 (nr_pages > MEMCG_CHARGE_BATCH || + !local_trylock(&memcg_stock.lock)) + return ret; - if (!failed) - return true; + stock = this_cpu_ptr(&memcg_stock); - /* - * 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; + for (i = 0; i < NR_MEMCG_STOCK; ++i) { + if (memcg != READ_ONCE(stock->cached[i])) + continue; + + stock_pages = READ_ONCE(stock->nr_pages[i]); + if (stock_pages >= nr_pages) { + WRITE_ONCE(stock->nr_pages[i], stock_pages - nr_pages); + ret = true; } - iter->oom_lock = false; + break; } - return false; + + local_unlock(&memcg_stock.lock); + + return ret; +} + +static void memcg_uncharge(struct mem_cgroup *memcg, unsigned int nr_pages) +{ + page_counter_uncharge(&memcg->memory, nr_pages); + if (do_memsw_account()) + page_counter_uncharge(&memcg->memsw, nr_pages); } /* - * Has to be called with memcg_oom_lock + * Returns stocks cached in percpu and reset cached information. */ -static int mem_cgroup_oom_unlock(struct mem_cgroup *memcg) +static void drain_stock(struct memcg_stock_pcp *stock, int i) { - struct mem_cgroup *iter; + struct mem_cgroup *old = READ_ONCE(stock->cached[i]); + uint8_t stock_pages; - for_each_mem_cgroup_tree(iter, memcg) - iter->oom_lock = false; - return 0; -} + if (!old) + return; -static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg) -{ - struct mem_cgroup *iter; + stock_pages = READ_ONCE(stock->nr_pages[i]); + if (stock_pages) { + memcg_uncharge(old, stock_pages); + WRITE_ONCE(stock->nr_pages[i], 0); + } - for_each_mem_cgroup_tree(iter, memcg) - atomic_inc(&iter->under_oom); + css_put(&old->css); + WRITE_ONCE(stock->cached[i], NULL); } -static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg) +static void drain_stock_fully(struct memcg_stock_pcp *stock) { - struct mem_cgroup *iter; + int i; - /* - * 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); + for (i = 0; i < NR_MEMCG_STOCK; ++i) + drain_stock(stock, i); } -static DEFINE_SPINLOCK(memcg_oom_lock); -static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq); +static void drain_local_memcg_stock(struct work_struct *dummy) +{ + struct memcg_stock_pcp *stock; -struct oom_wait_info { - struct mem_cgroup *memcg; - wait_queue_t wait; -}; + if (WARN_ONCE(!in_task(), "drain in non-task context")) + return; -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; + local_lock(&memcg_stock.lock); - oom_wait_info = container_of(wait, struct oom_wait_info, wait); - oom_wait_memcg = oom_wait_info->memcg; + stock = this_cpu_ptr(&memcg_stock); + drain_stock_fully(stock); + clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); - /* - * 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); + local_unlock(&memcg_stock.lock); } -static void memcg_wakeup_oom(struct mem_cgroup *memcg) +static void drain_local_obj_stock(struct work_struct *dummy) { - /* for filtering, pass "memcg" as argument. */ - __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg); + struct obj_stock_pcp *stock; + + if (WARN_ONCE(!in_task(), "drain in non-task context")) + return; + + local_lock(&obj_stock.lock); + + stock = this_cpu_ptr(&obj_stock); + drain_obj_stock(stock); + clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); + + local_unlock(&obj_stock.lock); } -static void memcg_oom_recover(struct mem_cgroup *memcg) +static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages) { - if (memcg && atomic_read(&memcg->under_oom)) - memcg_wakeup_oom(memcg); -} + struct memcg_stock_pcp *stock; + struct mem_cgroup *cached; + uint8_t stock_pages; + bool success = false; + int empty_slot = -1; + int i; -/* - * try to call OOM killer. returns false if we should exit memory-reclaim loop. - */ -static bool mem_cgroup_handle_oom(struct mem_cgroup *memcg, gfp_t mask, - int order) -{ - struct oom_wait_info owait; - bool locked, need_to_kill; - - owait.memcg = memcg; - owait.wait.flags = 0; - owait.wait.func = memcg_oom_wake_function; - owait.wait.private = current; - INIT_LIST_HEAD(&owait.wait.task_list); - need_to_kill = true; - mem_cgroup_mark_under_oom(memcg); - - /* At first, try to OOM lock hierarchy under memcg.*/ - spin_lock(&memcg_oom_lock); - locked = mem_cgroup_oom_lock(memcg); /* - * Even if signal_pending(), we can't quit charge() loop without - * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL - * under OOM is always welcomed, use TASK_KILLABLE here. + * For now limit MEMCG_CHARGE_BATCH to 127 and less. In future if we + * decide to increase it more than 127 then we will need more careful + * handling of nr_pages[] in struct memcg_stock_pcp. */ - prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE); - if (!locked || memcg->oom_kill_disable) - need_to_kill = false; - if (locked) - mem_cgroup_oom_notify(memcg); - spin_unlock(&memcg_oom_lock); - - if (need_to_kill) { - finish_wait(&memcg_oom_waitq, &owait.wait); - mem_cgroup_out_of_memory(memcg, mask, order); - } else { - schedule(); - finish_wait(&memcg_oom_waitq, &owait.wait); + BUILD_BUG_ON(MEMCG_CHARGE_BATCH > S8_MAX); + + VM_WARN_ON_ONCE(mem_cgroup_is_root(memcg)); + + if (nr_pages > MEMCG_CHARGE_BATCH || + !local_trylock(&memcg_stock.lock)) { + /* + * In case of larger than batch refill or unlikely failure to + * lock the percpu memcg_stock.lock, uncharge memcg directly. + */ + memcg_uncharge(memcg, nr_pages); + return; + } + + stock = this_cpu_ptr(&memcg_stock); + for (i = 0; i < NR_MEMCG_STOCK; ++i) { + cached = READ_ONCE(stock->cached[i]); + if (!cached && empty_slot == -1) + empty_slot = i; + if (memcg == READ_ONCE(stock->cached[i])) { + stock_pages = READ_ONCE(stock->nr_pages[i]) + nr_pages; + WRITE_ONCE(stock->nr_pages[i], stock_pages); + if (stock_pages > MEMCG_CHARGE_BATCH) + drain_stock(stock, i); + success = true; + break; + } } - spin_lock(&memcg_oom_lock); - if (locked) - mem_cgroup_oom_unlock(memcg); - memcg_wakeup_oom(memcg); - spin_unlock(&memcg_oom_lock); - mem_cgroup_unmark_under_oom(memcg); + if (!success) { + i = empty_slot; + if (i == -1) { + i = get_random_u32_below(NR_MEMCG_STOCK); + drain_stock(stock, i); + } + css_get(&memcg->css); + WRITE_ONCE(stock->cached[i], memcg); + WRITE_ONCE(stock->nr_pages[i], nr_pages); + } - if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current)) - return false; - /* Give chance to dying process */ - schedule_timeout_uninterruptible(1); - return true; + local_unlock(&memcg_stock.lock); +} + +static bool is_memcg_drain_needed(struct memcg_stock_pcp *stock, + struct mem_cgroup *root_memcg) +{ + struct mem_cgroup *memcg; + bool flush = false; + int i; + + rcu_read_lock(); + for (i = 0; i < NR_MEMCG_STOCK; ++i) { + memcg = READ_ONCE(stock->cached[i]); + if (!memcg) + continue; + + if (READ_ONCE(stock->nr_pages[i]) && + mem_cgroup_is_descendant(memcg, root_memcg)) { + flush = true; + break; + } + } + rcu_read_unlock(); + return flush; } /* - * 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. + * Drains all per-CPU charge caches for given root_memcg resp. subtree + * of the hierarchy under it. */ - -void __mem_cgroup_begin_update_page_stat(struct page *page, - bool *locked, unsigned long *flags) +void drain_all_stock(struct mem_cgroup *root_memcg) { - struct mem_cgroup *memcg; - struct page_cgroup *pc; + int cpu, curcpu; - pc = lookup_page_cgroup(page); -again: - memcg = pc->mem_cgroup; - if (unlikely(!memcg || !PageCgroupUsed(pc))) + /* If someone's already draining, avoid adding running more workers. */ + if (!mutex_trylock(&percpu_charge_mutex)) 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. + * Notify other cpus that system-wide "drain" is running + * We do not care about races with the cpu hotplug because cpu down + * as well as workers from this path always operate on the local + * per-cpu data. CPU up doesn't touch memcg_stock at all. */ - if (!mem_cgroup_stolen(memcg)) - return; + migrate_disable(); + curcpu = smp_processor_id(); + for_each_online_cpu(cpu) { + struct memcg_stock_pcp *memcg_st = &per_cpu(memcg_stock, cpu); + struct obj_stock_pcp *obj_st = &per_cpu(obj_stock, cpu); - move_lock_mem_cgroup(memcg, flags); - if (memcg != pc->mem_cgroup || !PageCgroupUsed(pc)) { - move_unlock_mem_cgroup(memcg, flags); - goto again; + if (!test_bit(FLUSHING_CACHED_CHARGE, &memcg_st->flags) && + is_memcg_drain_needed(memcg_st, root_memcg) && + !test_and_set_bit(FLUSHING_CACHED_CHARGE, + &memcg_st->flags)) { + if (cpu == curcpu) + drain_local_memcg_stock(&memcg_st->work); + else if (!cpu_is_isolated(cpu)) + schedule_work_on(cpu, &memcg_st->work); + } + + if (!test_bit(FLUSHING_CACHED_CHARGE, &obj_st->flags) && + obj_stock_flush_required(obj_st, root_memcg) && + !test_and_set_bit(FLUSHING_CACHED_CHARGE, + &obj_st->flags)) { + if (cpu == curcpu) + drain_local_obj_stock(&obj_st->work); + else if (!cpu_is_isolated(cpu)) + schedule_work_on(cpu, &obj_st->work); + } } - *locked = true; + migrate_enable(); + mutex_unlock(&percpu_charge_mutex); } -void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags) +static int memcg_hotplug_cpu_dead(unsigned int cpu) { - struct page_cgroup *pc = lookup_page_cgroup(page); + /* no need for the local lock */ + drain_obj_stock(&per_cpu(obj_stock, cpu)); + drain_stock_fully(&per_cpu(memcg_stock, cpu)); - /* - * 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); + return 0; } -void mem_cgroup_update_page_stat(struct page *page, - enum mem_cgroup_page_stat_item idx, int val) +static unsigned long reclaim_high(struct mem_cgroup *memcg, + unsigned int nr_pages, + gfp_t gfp_mask) { - struct mem_cgroup *memcg; - struct page_cgroup *pc = lookup_page_cgroup(page); - unsigned long uninitialized_var(flags); + unsigned long nr_reclaimed = 0; - if (mem_cgroup_disabled()) - return; + do { + unsigned long pflags; - memcg = pc->mem_cgroup; - if (unlikely(!memcg || !PageCgroupUsed(pc))) - return; + if (page_counter_read(&memcg->memory) <= + READ_ONCE(memcg->memory.high)) + continue; - switch (idx) { - case MEMCG_NR_FILE_MAPPED: - idx = MEM_CGROUP_STAT_FILE_MAPPED; - break; - default: - BUG(); - } + memcg_memory_event(memcg, MEMCG_HIGH); + + psi_memstall_enter(&pflags); + nr_reclaimed += try_to_free_mem_cgroup_pages(memcg, nr_pages, + gfp_mask, + MEMCG_RECLAIM_MAY_SWAP, + NULL); + psi_memstall_leave(&pflags); + } while ((memcg = parent_mem_cgroup(memcg)) && + !mem_cgroup_is_root(memcg)); + + return nr_reclaimed; +} - this_cpu_add(memcg->stat->count[idx], val); +static void high_work_func(struct work_struct *work) +{ + struct mem_cgroup *memcg; + + memcg = container_of(work, struct mem_cgroup, high_work); + reclaim_high(memcg, MEMCG_CHARGE_BATCH, GFP_KERNEL); } /* - * size of first charge trial. "32" comes from vmscan.c's magic value. - * TODO: maybe necessary to use big numbers in big irons. + * Clamp the maximum sleep time per allocation batch to 2 seconds. This is + * enough to still cause a significant slowdown in most cases, while still + * allowing diagnostics and tracing to proceed without becoming stuck. */ -#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); +#define MEMCG_MAX_HIGH_DELAY_JIFFIES (2UL*HZ) -/** - * consume_stock: Try to consume stocked charge on this cpu. - * @memcg: memcg to consume from. - * @nr_pages: how many pages to charge. +/* + * When calculating the delay, we use these either side of the exponentiation to + * maintain precision and scale to a reasonable number of jiffies (see the table + * below. * - * 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. + * - MEMCG_DELAY_PRECISION_SHIFT: Extra precision bits while translating the + * overage ratio to a delay. + * - MEMCG_DELAY_SCALING_SHIFT: The number of bits to scale down the + * proposed penalty in order to reduce to a reasonable number of jiffies, and + * to produce a reasonable delay curve. * - * returns true if successful, false otherwise. + * MEMCG_DELAY_SCALING_SHIFT just happens to be a number that produces a + * reasonable delay curve compared to precision-adjusted overage, not + * penalising heavily at first, but still making sure that growth beyond the + * limit penalises misbehaviour cgroups by slowing them down exponentially. For + * example, with a high of 100 megabytes: + * + * +-------+------------------------+ + * | usage | time to allocate in ms | + * +-------+------------------------+ + * | 100M | 0 | + * | 101M | 6 | + * | 102M | 25 | + * | 103M | 57 | + * | 104M | 102 | + * | 105M | 159 | + * | 106M | 230 | + * | 107M | 313 | + * | 108M | 409 | + * | 109M | 518 | + * | 110M | 639 | + * | 111M | 774 | + * | 112M | 921 | + * | 113M | 1081 | + * | 114M | 1254 | + * | 115M | 1439 | + * | 116M | 1638 | + * | 117M | 1849 | + * | 118M | 2000 | + * | 119M | 2000 | + * | 120M | 2000 | + * +-------+------------------------+ */ -static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages) + #define MEMCG_DELAY_PRECISION_SHIFT 20 + #define MEMCG_DELAY_SCALING_SHIFT 14 + +static u64 calculate_overage(unsigned long usage, unsigned long high) { - struct memcg_stock_pcp *stock; - bool ret = true; + u64 overage; - if (nr_pages > CHARGE_BATCH) - return false; + if (usage <= high) + return 0; - 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; + /* + * Prevent division by 0 in overage calculation by acting as if + * it was a threshold of 1 page + */ + high = max(high, 1UL); + + overage = usage - high; + overage <<= MEMCG_DELAY_PRECISION_SHIFT; + return div64_u64(overage, high); } -/* - * Returns stocks cached in percpu to res_counter and reset cached information. - */ -static void drain_stock(struct memcg_stock_pcp *stock) +static u64 mem_find_max_overage(struct mem_cgroup *memcg) { - struct mem_cgroup *old = stock->cached; + u64 overage, max_overage = 0; - if (stock->nr_pages) { - unsigned long bytes = stock->nr_pages * PAGE_SIZE; + do { + overage = calculate_overage(page_counter_read(&memcg->memory), + READ_ONCE(memcg->memory.high)); + max_overage = max(overage, max_overage); + } while ((memcg = parent_mem_cgroup(memcg)) && + !mem_cgroup_is_root(memcg)); - res_counter_uncharge(&old->res, bytes); - if (do_swap_account) - res_counter_uncharge(&old->memsw, bytes); - stock->nr_pages = 0; - } - stock->cached = NULL; + return max_overage; } -/* - * 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) +static u64 swap_find_max_overage(struct mem_cgroup *memcg) { - struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock); - drain_stock(stock); - clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); -} + u64 overage, max_overage = 0; -static void __init memcg_stock_init(void) -{ - int cpu; + do { + overage = calculate_overage(page_counter_read(&memcg->swap), + READ_ONCE(memcg->swap.high)); + if (overage) + memcg_memory_event(memcg, MEMCG_SWAP_HIGH); + max_overage = max(overage, max_overage); + } while ((memcg = parent_mem_cgroup(memcg)) && + !mem_cgroup_is_root(memcg)); - for_each_possible_cpu(cpu) { - struct memcg_stock_pcp *stock = - &per_cpu(memcg_stock, cpu); - INIT_WORK(&stock->work, drain_local_stock); - } + return max_overage; } /* - * Cache charges(val) which is from res_counter, to local per_cpu area. - * This will be consumed by consume_stock() function, later. + * Get the number of jiffies that we should penalise a mischievous cgroup which + * is exceeding its memory.high by checking both it and its ancestors. */ -static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages) +static unsigned long calculate_high_delay(struct mem_cgroup *memcg, + unsigned int nr_pages, + u64 max_overage) { - struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock); + unsigned long penalty_jiffies; - if (stock->cached != memcg) { /* reset if necessary */ - drain_stock(stock); - stock->cached = memcg; - } - stock->nr_pages += nr_pages; - put_cpu_var(memcg_stock); + if (!max_overage) + return 0; + + /* + * We use overage compared to memory.high to calculate the number of + * jiffies to sleep (penalty_jiffies). Ideally this value should be + * fairly lenient on small overages, and increasingly harsh when the + * memcg in question makes it clear that it has no intention of stopping + * its crazy behaviour, so we exponentially increase the delay based on + * overage amount. + */ + penalty_jiffies = max_overage * max_overage * HZ; + penalty_jiffies >>= MEMCG_DELAY_PRECISION_SHIFT; + penalty_jiffies >>= MEMCG_DELAY_SCALING_SHIFT; + + /* + * Factor in the task's own contribution to the overage, such that four + * N-sized allocations are throttled approximately the same as one + * 4N-sized allocation. + * + * MEMCG_CHARGE_BATCH pages is nominal, so work out how much smaller or + * larger the current charge patch is than that. + */ + return penalty_jiffies * nr_pages / MEMCG_CHARGE_BATCH; } /* - * 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. + * Reclaims memory over the high limit. Called directly from + * try_charge() (context permitting), as well as from the userland + * return path where reclaim is always able to block. */ -static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync) +void __mem_cgroup_handle_over_high(gfp_t gfp_mask) { - int cpu, curcpu; + unsigned long penalty_jiffies; + unsigned long pflags; + unsigned long nr_reclaimed; + unsigned int nr_pages = current->memcg_nr_pages_over_high; + int nr_retries = MAX_RECLAIM_RETRIES; + struct mem_cgroup *memcg; + bool in_retry = false; - /* 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 = get_mem_cgroup_from_mm(current->mm); + current->memcg_nr_pages_over_high = 0; - 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) +retry_reclaim: + /* + * Bail if the task is already exiting. Unlike memory.max, + * memory.high enforcement isn't as strict, and there is no + * OOM killer involved, which means the excess could already + * be much bigger (and still growing) than it could for + * memory.max; the dying task could get stuck in fruitless + * reclaim for a long time, which isn't desirable. + */ + if (task_is_dying()) 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(); -} + /* + * The allocating task should reclaim at least the batch size, but for + * subsequent retries we only want to do what's necessary to prevent oom + * or breaching resource isolation. + * + * This is distinct from memory.max or page allocator behaviour because + * memory.high is currently batched, whereas memory.max and the page + * allocator run every time an allocation is made. + */ + nr_reclaimed = reclaim_high(memcg, + in_retry ? SWAP_CLUSTER_MAX : nr_pages, + gfp_mask); -/* - * 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. + * memory.high is breached and reclaim is unable to keep up. Throttle + * allocators proactively to slow down excessive growth. */ - if (!mutex_trylock(&percpu_charge_mutex)) - return; - drain_all_stock(root_memcg, false); - mutex_unlock(&percpu_charge_mutex); -} + penalty_jiffies = calculate_high_delay(memcg, nr_pages, + mem_find_max_overage(memcg)); -/* 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); -} + penalty_jiffies += calculate_high_delay(memcg, nr_pages, + swap_find_max_overage(memcg)); -/* - * 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; + /* + * Clamp the max delay per usermode return so as to still keep the + * application moving forwards and also permit diagnostics, albeit + * extremely slowly. + */ + penalty_jiffies = min(penalty_jiffies, MEMCG_MAX_HIGH_DELAY_JIFFIES); - spin_lock(&memcg->pcp_counter_lock); - for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { - long x = per_cpu(memcg->stat->count[i], cpu); + /* + * Don't sleep if the amount of jiffies this memcg owes us is so low + * that it's not even worth doing, in an attempt to be nice to those who + * go only a small amount over their memory.high value and maybe haven't + * been aggressively reclaimed enough yet. + */ + if (penalty_jiffies <= HZ / 100) + goto out; - per_cpu(memcg->stat->count[i], cpu) = 0; - memcg->nocpu_base.count[i] += x; + /* + * If reclaim is making forward progress but we're still over + * memory.high, we want to encourage that rather than doing allocator + * throttling. + */ + if (nr_reclaimed || nr_retries--) { + in_retry = true; + goto retry_reclaim; } - 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); + /* + * Reclaim didn't manage to push usage below the limit, slow + * this allocating task down. + * + * If we exit early, we're guaranteed to die (since + * schedule_timeout_killable sets TASK_KILLABLE). This means we don't + * need to account for any ill-begotten jiffies to pay them off later. + */ + psi_memstall_enter(&pflags); + schedule_timeout_killable(penalty_jiffies); + psi_memstall_leave(&pflags); + +out: + css_put(&memcg->css); } -static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb, - unsigned long action, - void *hcpu) +static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask, + unsigned int nr_pages) { - int cpu = (unsigned long)hcpu; - struct memcg_stock_pcp *stock; - struct mem_cgroup *iter; - - if (action == CPU_ONLINE) - return NOTIFY_OK; + unsigned int batch = max(MEMCG_CHARGE_BATCH, nr_pages); + int nr_retries = MAX_RECLAIM_RETRIES; + struct mem_cgroup *mem_over_limit; + struct page_counter *counter; + unsigned long nr_reclaimed; + bool passed_oom = false; + unsigned int reclaim_options = MEMCG_RECLAIM_MAY_SWAP; + bool drained = false; + bool raised_max_event = false; + unsigned long pflags; + bool allow_spinning = gfpflags_allow_spinning(gfp_mask); - if (action != CPU_DEAD && action != CPU_DEAD_FROZEN) - return NOTIFY_OK; +retry: + if (consume_stock(memcg, nr_pages)) + return 0; - for_each_mem_cgroup(iter) - mem_cgroup_drain_pcp_counter(iter, cpu); + if (!allow_spinning) + /* Avoid the refill and flush of the older stock */ + batch = nr_pages; + + if (!do_memsw_account() || + page_counter_try_charge(&memcg->memsw, batch, &counter)) { + if (page_counter_try_charge(&memcg->memory, batch, &counter)) + goto done_restock; + if (do_memsw_account()) + page_counter_uncharge(&memcg->memsw, batch); + mem_over_limit = mem_cgroup_from_counter(counter, memory); + } else { + mem_over_limit = mem_cgroup_from_counter(counter, memsw); + reclaim_options &= ~MEMCG_RECLAIM_MAY_SWAP; + } - stock = &per_cpu(memcg_stock, cpu); - drain_stock(stock); - return NOTIFY_OK; -} + if (batch > nr_pages) { + batch = nr_pages; + goto retry; + } + /* + * Prevent unbounded recursion when reclaim operations need to + * allocate memory. This might exceed the limits temporarily, + * but we prefer facilitating memory reclaim and getting back + * under the limit over triggering OOM kills in these cases. + */ + if (unlikely(current->flags & PF_MEMALLOC)) + goto force; -/* See __mem_cgroup_try_charge() for details */ -enum { - CHARGE_OK, /* success */ - CHARGE_RETRY, /* need to retry but retry is not bad */ - CHARGE_NOMEM, /* we can't do more. return -ENOMEM */ - CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */ - CHARGE_OOM_DIE, /* the current is killed because of OOM */ -}; + if (unlikely(task_in_memcg_oom(current))) + goto nomem; -static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, - unsigned int nr_pages, unsigned int min_pages, - bool oom_check) -{ - unsigned long csize = nr_pages * PAGE_SIZE; - struct mem_cgroup *mem_over_limit; - struct res_counter *fail_res; - unsigned long flags = 0; - int ret; + if (!gfpflags_allow_blocking(gfp_mask)) + goto nomem; - ret = res_counter_charge(&memcg->res, csize, &fail_res); + __memcg_memory_event(mem_over_limit, MEMCG_MAX, allow_spinning); + raised_max_event = true; - 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; + psi_memstall_enter(&pflags); + nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages, + gfp_mask, reclaim_options, NULL); + psi_memstall_leave(&pflags); - 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 (mem_cgroup_margin(mem_over_limit) >= nr_pages) + goto retry; - if (!(gfp_mask & __GFP_WAIT)) - return CHARGE_WOULDBLOCK; + if (!drained) { + drain_all_stock(mem_over_limit); + drained = true; + goto retry; + } 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; + goto nomem; /* * Even though the limit is exceeded at this point, reclaim * may have been able to free some pages. Retry the charge @@ -2603,4413 +2409,3235 @@ static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, * 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 (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER)) + goto retry; - /* If we don't need to call oom-killer at el, return immediately */ - if (!oom_check) - return CHARGE_NOMEM; - /* check OOM */ - if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask, get_order(csize))) - return CHARGE_OOM_DIE; + if (nr_retries--) + goto retry; - return CHARGE_RETRY; -} + if (gfp_mask & __GFP_RETRY_MAYFAIL) + goto nomem; -/* - * __mem_cgroup_try_charge() does - * 1. detect memcg to be charged against from passed *mm and *ptr, - * 2. update res_counter - * 3. call memory reclaim if necessary. - * - * In some special case, if the task is fatal, fatal_signal_pending() or - * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup - * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon - * as possible without any hazards. 2: all pages should have a valid - * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg - * pointer, that is treated as a charge to root_mem_cgroup. - * - * So __mem_cgroup_try_charge() will return - * 0 ... on success, filling *ptr with a valid memcg pointer. - * -ENOMEM ... charge failure because of resource limits. - * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup. - * - * Unlike the exported interface, an "oom" parameter is added. if oom==true, - * the oom-killer can be invoked. - */ -static int __mem_cgroup_try_charge(struct mm_struct *mm, - gfp_t gfp_mask, - unsigned int nr_pages, - struct mem_cgroup **ptr, - bool oom) -{ - unsigned int batch = max(CHARGE_BATCH, nr_pages); - int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; - struct mem_cgroup *memcg = NULL; - int ret; + /* Avoid endless loop for tasks bypassed by the oom killer */ + if (passed_oom && task_is_dying()) + goto nomem; /* - * Unlike gloval-vm's OOM-kill, we're not in memory shortage - * in system level. So, allow to go ahead dying process in addition to - * MEMDIE process. + * keep retrying as long as the memcg oom killer is able to make + * a forward progress or bypass the charge if the oom killer + * couldn't make any progress. */ - if (unlikely(test_thread_flag(TIF_MEMDIE) - || fatal_signal_pending(current))) - goto bypass; + if (mem_cgroup_oom(mem_over_limit, gfp_mask, + get_order(nr_pages * PAGE_SIZE))) { + passed_oom = true; + nr_retries = MAX_RECLAIM_RETRIES; + goto retry; + } +nomem: + /* + * Memcg doesn't have a dedicated reserve for atomic + * allocations. But like the global atomic pool, we need to + * put the burden of reclaim on regular allocation requests + * and let these go through as privileged allocations. + */ + if (!(gfp_mask & (__GFP_NOFAIL | __GFP_HIGH))) + return -ENOMEM; +force: + /* + * If the allocation has to be enforced, don't forget to raise + * a MEMCG_MAX event. + */ + if (!raised_max_event) + __memcg_memory_event(mem_over_limit, MEMCG_MAX, allow_spinning); /* - * We always charge the cgroup the mm_struct belongs to. - * The mm_struct's mem_cgroup changes on task migration if the - * thread group leader migrates. It's possible that mm is not - * set, if so charge the root memcg (happens for pagecache usage). + * The allocation either can't fail or will lead to more memory + * being freed very soon. Allow memory usage go over the limit + * temporarily by force charging it. */ - if (!*ptr && !mm) - *ptr = root_mem_cgroup; -again: - if (*ptr) { /* css should be a valid one */ - memcg = *ptr; - if (mem_cgroup_is_root(memcg)) - goto done; - if (consume_stock(memcg, nr_pages)) - goto done; - css_get(&memcg->css); - } else { - struct task_struct *p; + page_counter_charge(&memcg->memory, nr_pages); + if (do_memsw_account()) + page_counter_charge(&memcg->memsw, nr_pages); - rcu_read_lock(); - p = rcu_dereference(mm->owner); - /* - * Because we don't have task_lock(), "p" can exit. - * In that case, "memcg" can point to root or p can be NULL with - * race with swapoff. Then, we have small risk of mis-accouning. - * But such kind of mis-account by race always happens because - * we don't have cgroup_mutex(). It's overkill and we allo that - * small race, here. - * (*) swapoff at el will charge against mm-struct not against - * task-struct. So, mm->owner can be NULL. - */ - memcg = mem_cgroup_from_task(p); - if (!memcg) - memcg = root_mem_cgroup; - if (mem_cgroup_is_root(memcg)) { - rcu_read_unlock(); - goto done; - } - if (consume_stock(memcg, nr_pages)) { - /* - * It seems dagerous to access memcg without css_get(). - * But considering how consume_stok works, it's not - * necessary. If consume_stock success, some charges - * from this memcg are cached on this cpu. So, we - * don't need to call css_get()/css_tryget() before - * calling consume_stock(). - */ - rcu_read_unlock(); - goto done; - } - /* after here, we may be blocked. we need to get refcnt */ - if (!css_tryget(&memcg->css)) { - rcu_read_unlock(); - goto again; - } - rcu_read_unlock(); - } + return 0; + +done_restock: + if (batch > nr_pages) + refill_stock(memcg, batch - nr_pages); + /* + * If the hierarchy is above the normal consumption range, schedule + * reclaim on returning to userland. We can perform reclaim here + * if __GFP_RECLAIM but let's always punt for simplicity and so that + * GFP_KERNEL can consistently be used during reclaim. @memcg is + * not recorded as it most likely matches current's and won't + * change in the meantime. As high limit is checked again before + * reclaim, the cost of mismatch is negligible. + */ do { - bool oom_check; + bool mem_high, swap_high; - /* If killed, bypass charge */ - if (fatal_signal_pending(current)) { - css_put(&memcg->css); - goto bypass; - } + mem_high = page_counter_read(&memcg->memory) > + READ_ONCE(memcg->memory.high); + swap_high = page_counter_read(&memcg->swap) > + READ_ONCE(memcg->swap.high); - oom_check = false; - if (oom && !nr_oom_retries) { - oom_check = true; - nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; + /* Don't bother a random interrupted task */ + if (!in_task()) { + if (mem_high) { + schedule_work(&memcg->high_work); + break; + } + continue; } - ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, nr_pages, - oom_check); - switch (ret) { - case CHARGE_OK: - break; - case CHARGE_RETRY: /* not in OOM situation but retry */ - batch = nr_pages; - css_put(&memcg->css); - memcg = NULL; - goto again; - case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */ - css_put(&memcg->css); - goto nomem; - case CHARGE_NOMEM: /* OOM routine works */ - if (!oom) { - css_put(&memcg->css); - goto nomem; - } - /* If oom, we never return -ENOMEM */ - nr_oom_retries--; + if (mem_high || swap_high) { + /* + * The allocating tasks in this cgroup will need to do + * reclaim or be throttled to prevent further growth + * of the memory or swap footprints. + * + * Target some best-effort fairness between the tasks, + * and distribute reclaim work and delay penalties + * based on how much each task is actually allocating. + */ + current->memcg_nr_pages_over_high += batch; + set_notify_resume(current); break; - case CHARGE_OOM_DIE: /* Killed by OOM Killer */ - css_put(&memcg->css); - goto bypass; } - } while (ret != CHARGE_OK); + } while ((memcg = parent_mem_cgroup(memcg))); - if (batch > nr_pages) - refill_stock(memcg, batch - nr_pages); - css_put(&memcg->css); -done: - *ptr = memcg; + /* + * Reclaim is set up above to be called from the userland + * return path. But also attempt synchronous reclaim to avoid + * excessive overrun while the task is still inside the + * kernel. If this is successful, the return path will see it + * when it rechecks the overage and simply bail out. + */ + if (current->memcg_nr_pages_over_high > MEMCG_CHARGE_BATCH && + !(current->flags & PF_MEMALLOC) && + gfpflags_allow_blocking(gfp_mask)) + __mem_cgroup_handle_over_high(gfp_mask); return 0; -nomem: - *ptr = NULL; - return -ENOMEM; -bypass: - *ptr = root_mem_cgroup; - return -EINTR; -} - -/* - * Somemtimes we have to undo a charge we got by try_charge(). - * This function is for that and do uncharge, put css's refcnt. - * gotten by try_charge(). - */ -static void __mem_cgroup_cancel_charge(struct mem_cgroup *memcg, - unsigned int nr_pages) -{ - if (!mem_cgroup_is_root(memcg)) { - unsigned long bytes = nr_pages * PAGE_SIZE; - - res_counter_uncharge(&memcg->res, bytes); - if (do_swap_account) - res_counter_uncharge(&memcg->memsw, bytes); - } } -/* - * 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) +static inline int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, + 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) -{ - struct cgroup_subsys_state *css; - - /* ID 0 is unused ID */ - if (!id) - return NULL; - css = css_lookup(&mem_cgroup_subsys, id); - if (!css) - return NULL; - return mem_cgroup_from_css(css); -} + return 0; -struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) -{ - struct mem_cgroup *memcg = NULL; - struct page_cgroup *pc; - unsigned short id; - swp_entry_t ent; - - VM_BUG_ON(!PageLocked(page)); - - pc = lookup_page_cgroup(page); - lock_page_cgroup(pc); - if (PageCgroupUsed(pc)) { - memcg = pc->mem_cgroup; - if (memcg && !css_tryget(&memcg->css)) - memcg = NULL; - } else if (PageSwapCache(page)) { - ent.val = page_private(page); - id = lookup_swap_cgroup_id(ent); - rcu_read_lock(); - memcg = mem_cgroup_lookup(id); - if (memcg && !css_tryget(&memcg->css)) - memcg = NULL; - rcu_read_unlock(); - } - unlock_page_cgroup(pc); - return memcg; + return try_charge_memcg(memcg, gfp_mask, nr_pages); } -static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, - struct page *page, - unsigned int nr_pages, - enum charge_type ctype, - bool lrucare) +static void commit_charge(struct folio *folio, struct mem_cgroup *memcg) { - 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(PageCgroupUsed(pc)); - /* - * 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(PageLRU(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); - + VM_BUG_ON_FOLIO(folio_memcg_charged(folio), folio); /* - * "charge_statistics" updated event counter. Then, check it. - * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree. - * if they exceeds softlimit. + * Any of the following ensures page's memcg stability: + * + * - the page lock + * - LRU isolation + * - exclusive reference */ - memcg_check_events(memcg, page); + folio->memcg_data = (unsigned long)memcg; } -static DEFINE_MUTEX(set_limit_mutex); - -#ifdef CONFIG_MEMCG_KMEM -static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg) +#ifdef CONFIG_MEMCG_NMI_SAFETY_REQUIRES_ATOMIC +static inline void account_slab_nmi_safe(struct mem_cgroup *memcg, + struct pglist_data *pgdat, + enum node_stat_item idx, int nr) { - return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) && - (memcg->kmem_account_flags & KMEM_ACCOUNTED_MASK); -} + struct lruvec *lruvec; -/* - * 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; + if (likely(!in_nmi())) { + lruvec = mem_cgroup_lruvec(memcg, pgdat); + mod_memcg_lruvec_state(lruvec, idx, nr); + } else { + struct mem_cgroup_per_node *pn = memcg->nodeinfo[pgdat->node_id]; - VM_BUG_ON(p->is_root_cache); - cachep = p->root_cache; - return cachep->memcg_params->memcg_caches[memcg_cache_id(p->memcg)]; + /* preemption is disabled in_nmi(). */ + css_rstat_updated(&memcg->css, smp_processor_id()); + if (idx == NR_SLAB_RECLAIMABLE_B) + atomic_add(nr, &pn->slab_reclaimable); + else + atomic_add(nr, &pn->slab_unreclaimable); + } } - -#ifdef CONFIG_SLABINFO -static int mem_cgroup_slabinfo_read(struct cgroup *cont, struct cftype *cft, - struct seq_file *m) +#else +static inline void account_slab_nmi_safe(struct mem_cgroup *memcg, + struct pglist_data *pgdat, + enum node_stat_item idx, int nr) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); - 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); + struct lruvec *lruvec; - return 0; + lruvec = mem_cgroup_lruvec(memcg, pgdat); + mod_memcg_lruvec_state(lruvec, idx, nr); } #endif -static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, u64 size) +static inline void mod_objcg_mlstate(struct obj_cgroup *objcg, + struct pglist_data *pgdat, + enum node_stat_item idx, int nr) { - struct res_counter *fail_res; - struct mem_cgroup *_memcg; - int ret = 0; - bool may_oom; - - ret = res_counter_charge(&memcg->kmem, size, &fail_res); - if (ret) - return ret; - - /* - * Conditions under which we can wait for the oom_killer. Those are - * the same conditions tested by the core page allocator - */ - may_oom = (gfp & __GFP_FS) && !(gfp & __GFP_NORETRY); - - _memcg = memcg; - ret = __mem_cgroup_try_charge(NULL, gfp, size >> PAGE_SHIFT, - &_memcg, may_oom); - - 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); + struct mem_cgroup *memcg; - return ret; + rcu_read_lock(); + memcg = obj_cgroup_memcg(objcg); + account_slab_nmi_safe(memcg, pgdat, idx, nr); + rcu_read_unlock(); } -static void memcg_uncharge_kmem(struct mem_cgroup *memcg, u64 size) +static __always_inline +struct mem_cgroup *mem_cgroup_from_obj_slab(struct slab *slab, void *p) { - 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(). + * Slab objects are accounted individually, not per-page. + * Memcg membership data for each individual object is saved in + * slab->obj_exts. */ - if (memcg_kmem_test_and_clear_dead(memcg)) - css_put(&memcg->css); -} + struct slabobj_ext *obj_exts; + unsigned int off; -void memcg_cache_list_add(struct mem_cgroup *memcg, struct kmem_cache *cachep) -{ - if (!memcg) - return; + obj_exts = slab_obj_exts(slab); + if (!obj_exts) + return NULL; - mutex_lock(&memcg->slab_caches_mutex); - list_add(&cachep->memcg_params->list, &memcg->memcg_slab_caches); - mutex_unlock(&memcg->slab_caches_mutex); -} + off = obj_to_index(slab->slab_cache, slab, p); + if (obj_exts[off].objcg) + return obj_cgroup_memcg(obj_exts[off].objcg); -/* - * 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; + return NULL; } /* - * This ends up being protected by the set_limit mutex, during normal - * operation, because that is its main call site. + * Returns a pointer to the memory cgroup to which the kernel object is charged. + * It is not suitable for objects allocated using vmalloc(). * - * But when we create a new cache, we can call this as well if its parent - * is kmem-limited. That will have to hold set_limit_mutex as well. + * A passed kernel object must be a slab object or a generic kernel page. + * + * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(), + * cgroup_mutex, etc. */ -int memcg_update_cache_sizes(struct mem_cgroup *memcg) +struct mem_cgroup *mem_cgroup_from_slab_obj(void *p) { - int num, ret; + struct slab *slab; - num = ida_simple_get(&kmem_limited_groups, - 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL); - if (num < 0) - return num; - /* - * After this point, kmem_accounted (that we test atomically in - * the beginning of this conditional), is no longer 0. This - * guarantees only one process will set the following boolean - * to true. We don't need test_and_set because we're protected - * by the set_limit_mutex anyway. - */ - memcg_kmem_set_activated(memcg); - - ret = memcg_update_all_caches(num+1); - if (ret) { - ida_simple_remove(&kmem_limited_groups, num); - memcg_kmem_clear_activated(memcg); - return ret; - } + if (mem_cgroup_disabled()) + return NULL; - memcg->kmemcg_id = num; - INIT_LIST_HEAD(&memcg->memcg_slab_caches); - mutex_init(&memcg->slab_caches_mutex); - return 0; + slab = virt_to_slab(p); + if (slab) + return mem_cgroup_from_obj_slab(slab, p); + return folio_memcg_check(virt_to_folio(p)); } -static size_t memcg_caches_array_size(int num_groups) +static struct obj_cgroup *__get_obj_cgroup_from_memcg(struct mem_cgroup *memcg) { - 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; + struct obj_cgroup *objcg = NULL; - 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); + for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) { + objcg = rcu_dereference(memcg->objcg); + if (likely(objcg && obj_cgroup_tryget(objcg))) + break; + objcg = NULL; + } + return objcg; } -static void kmem_cache_destroy_work_func(struct work_struct *w); - -int memcg_update_cache_size(struct kmem_cache *s, int num_groups) +static struct obj_cgroup *current_objcg_update(void) { - struct memcg_cache_params *cur_params = s->memcg_params; - - VM_BUG_ON(s->memcg_params && !s->memcg_params->is_root_cache); - - if (num_groups > memcg_limited_groups_array_size) { - int i; - ssize_t size = memcg_caches_array_size(num_groups); - - size *= sizeof(void *); - size += sizeof(struct memcg_cache_params); + struct mem_cgroup *memcg; + struct obj_cgroup *old, *objcg = NULL; - s->memcg_params = kzalloc(size, GFP_KERNEL); - if (!s->memcg_params) { - s->memcg_params = cur_params; - return -ENOMEM; + do { + /* Atomically drop the update bit. */ + old = xchg(¤t->objcg, NULL); + if (old) { + old = (struct obj_cgroup *) + ((unsigned long)old & ~CURRENT_OBJCG_UPDATE_FLAG); + obj_cgroup_put(old); + + old = NULL; } - s->memcg_params->is_root_cache = true; + /* If new objcg is NULL, no reason for the second atomic update. */ + if (!current->mm || (current->flags & PF_KTHREAD)) + return NULL; /* - * 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 + * Release the objcg pointer from the previous iteration, + * if try_cmpxcg() below fails. */ - for (i = 0; i < memcg_limited_groups_array_size; i++) { - if (!cur_params->memcg_caches[i]) - continue; - s->memcg_params->memcg_caches[i] = - cur_params->memcg_caches[i]; + if (unlikely(objcg)) { + obj_cgroup_put(objcg); + objcg = NULL; } /* - * 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. + * Obtain the new objcg pointer. The current task can be + * asynchronously moved to another memcg and the previous + * memcg can be offlined. So let's get the memcg pointer + * and try get a reference to objcg under a rcu read lock. */ - kfree(cur_params); - } - return 0; -} - -int memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s, - struct kmem_cache *root_cache) -{ - size_t size = sizeof(struct memcg_cache_params); - - if (!memcg_kmem_enabled()) - return 0; - - if (!memcg) - size += memcg_limited_groups_array_size * sizeof(void *); - s->memcg_params = kzalloc(size, GFP_KERNEL); - if (!s->memcg_params) - return -ENOMEM; + rcu_read_lock(); + memcg = mem_cgroup_from_task(current); + objcg = __get_obj_cgroup_from_memcg(memcg); + rcu_read_unlock(); - INIT_WORK(&s->memcg_params->destroy, - kmem_cache_destroy_work_func); - if (memcg) { - s->memcg_params->memcg = memcg; - s->memcg_params->root_cache = root_cache; - } else - s->memcg_params->is_root_cache = true; + /* + * Try set up a new objcg pointer atomically. If it + * fails, it means the update flag was set concurrently, so + * the whole procedure should be repeated. + */ + } while (!try_cmpxchg(¤t->objcg, &old, objcg)); - return 0; + return objcg; } -void memcg_release_cache(struct kmem_cache *s) +__always_inline struct obj_cgroup *current_obj_cgroup(void) { - struct kmem_cache *root; struct mem_cgroup *memcg; - int id; + struct obj_cgroup *objcg; - /* - * This happens, for instance, when a root cache goes away before we - * add any memcg. - */ - if (!s->memcg_params) - return; - - if (s->memcg_params->is_root_cache) - goto out; + if (IS_ENABLED(CONFIG_MEMCG_NMI_UNSAFE) && in_nmi()) + return NULL; - memcg = s->memcg_params->memcg; - id = memcg_cache_id(memcg); + if (in_task()) { + memcg = current->active_memcg; + if (unlikely(memcg)) + goto from_memcg; - root = s->memcg_params->root_cache; - root->memcg_params->memcg_caches[id] = NULL; + objcg = READ_ONCE(current->objcg); + if (unlikely((unsigned long)objcg & CURRENT_OBJCG_UPDATE_FLAG)) + objcg = current_objcg_update(); + /* + * Objcg reference is kept by the task, so it's safe + * to use the objcg by the current task. + */ + return objcg; + } - mutex_lock(&memcg->slab_caches_mutex); - list_del(&s->memcg_params->list); - mutex_unlock(&memcg->slab_caches_mutex); + memcg = this_cpu_read(int_active_memcg); + if (unlikely(memcg)) + goto from_memcg; - css_put(&memcg->css); -out: - kfree(s->memcg_params); -} + return 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++; -} +from_memcg: + objcg = NULL; + for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) { + /* + * Memcg pointer is protected by scope (see set_active_memcg()) + * and is pinning the corresponding objcg, so objcg can't go + * away and can be used within the scope without any additional + * protection. + */ + objcg = rcu_dereference_check(memcg->objcg, 1); + if (likely(objcg)) + break; + } -static inline void memcg_resume_kmem_account(void) -{ - VM_BUG_ON(!current->mm); - current->memcg_kmem_skip_account--; + return objcg; } -static void kmem_cache_destroy_work_func(struct work_struct *w) +struct obj_cgroup *get_obj_cgroup_from_folio(struct folio *folio) { - struct kmem_cache *cachep; - struct memcg_cache_params *p; + struct obj_cgroup *objcg; - p = container_of(w, struct memcg_cache_params, destroy); + if (!memcg_kmem_online()) + return NULL; - cachep = memcg_params_to_cache(p); + if (folio_memcg_kmem(folio)) { + objcg = __folio_objcg(folio); + obj_cgroup_get(objcg); + } else { + struct mem_cgroup *memcg; - /* - * 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); - if (atomic_read(&cachep->memcg_params->nr_pages) == 0) - return; - } else - kmem_cache_destroy(cachep); + rcu_read_lock(); + memcg = __folio_memcg(folio); + if (memcg) + objcg = __get_obj_cgroup_from_memcg(memcg); + else + objcg = NULL; + rcu_read_unlock(); + } + return objcg; } -void mem_cgroup_destroy_cache(struct kmem_cache *cachep) +#ifdef CONFIG_MEMCG_NMI_SAFETY_REQUIRES_ATOMIC +static inline void account_kmem_nmi_safe(struct mem_cgroup *memcg, int val) { - 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); + if (likely(!in_nmi())) { + mod_memcg_state(memcg, MEMCG_KMEM, val); + } else { + /* preemption is disabled in_nmi(). */ + css_rstat_updated(&memcg->css, smp_processor_id()); + atomic_add(val, &memcg->kmem_stat); + } } +#else +static inline void account_kmem_nmi_safe(struct mem_cgroup *memcg, int val) +{ + mod_memcg_state(memcg, MEMCG_KMEM, val); +} +#endif /* - * This lock protects updaters, not readers. We want readers to be as fast as - * they can, and they will either see NULL or a valid cache value. Our model - * allow them to see NULL, in which case the root memcg will be selected. - * - * We need this lock because multiple allocations to the same cache from a non - * will span more than one worker. Only one of them can create the cache. - */ -static DEFINE_MUTEX(memcg_cache_mutex); - -/* - * Called with memcg_cache_mutex held + * obj_cgroup_uncharge_pages: uncharge a number of kernel pages from a objcg + * @objcg: object cgroup to uncharge + * @nr_pages: number of pages to uncharge */ -static struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg, - struct kmem_cache *s) +static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg, + unsigned int nr_pages) { - struct kmem_cache *new; - static char *tmp_name = NULL; - - lockdep_assert_held(&memcg_cache_mutex); - - /* - * kmem_cache_create_memcg duplicates the given name and - * cgroup_name for this name requires RCU context. - * This static temporary buffer is used to prevent from - * pointless shortliving allocation. - */ - if (!tmp_name) { - tmp_name = kmalloc(PATH_MAX, GFP_KERNEL); - if (!tmp_name) - return NULL; - } - - rcu_read_lock(); - snprintf(tmp_name, PATH_MAX, "%s(%d:%s)", s->name, - memcg_cache_id(memcg), cgroup_name(memcg->css.cgroup)); - rcu_read_unlock(); + struct mem_cgroup *memcg; - new = kmem_cache_create_memcg(memcg, tmp_name, s->object_size, s->align, - (s->flags & ~SLAB_PANIC), s->ctor, s); + memcg = get_mem_cgroup_from_objcg(objcg); - if (new) - new->allocflags |= __GFP_KMEMCG; + account_kmem_nmi_safe(memcg, -nr_pages); + memcg1_account_kmem(memcg, -nr_pages); + if (!mem_cgroup_is_root(memcg)) + refill_stock(memcg, nr_pages); - return new; + css_put(&memcg->css); } -static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg, - struct kmem_cache *cachep) +/* + * obj_cgroup_charge_pages: charge a number of kernel pages to a objcg + * @objcg: object cgroup to charge + * @gfp: reclaim mode + * @nr_pages: number of pages to charge + * + * Returns 0 on success, an error code on failure. + */ +static int obj_cgroup_charge_pages(struct obj_cgroup *objcg, gfp_t gfp, + unsigned int nr_pages) { - struct kmem_cache *new_cachep; - int idx; - - BUG_ON(!memcg_can_account_kmem(memcg)); - - idx = memcg_cache_id(memcg); + struct mem_cgroup *memcg; + int ret; - mutex_lock(&memcg_cache_mutex); - new_cachep = cachep->memcg_params->memcg_caches[idx]; - if (new_cachep) { - css_put(&memcg->css); - goto out; - } + memcg = get_mem_cgroup_from_objcg(objcg); - new_cachep = kmem_cache_dup(memcg, cachep); - if (new_cachep == NULL) { - new_cachep = cachep; - css_put(&memcg->css); + ret = try_charge_memcg(memcg, gfp, nr_pages); + if (ret) goto out; - } - - atomic_set(&new_cachep->memcg_params->nr_pages , 0); - cachep->memcg_params->memcg_caches[idx] = new_cachep; - /* - * the readers won't lock, make sure everybody sees the updated value, - * so they won't put stuff in the queue again for no reason - */ - wmb(); + account_kmem_nmi_safe(memcg, nr_pages); + memcg1_account_kmem(memcg, nr_pages); out: - mutex_unlock(&memcg_cache_mutex); - return new_cachep; -} - -void kmem_cache_destroy_memcg_children(struct kmem_cache *s) -{ - struct kmem_cache *c; - int i; - - if (!s->memcg_params) - return; - if (!s->memcg_params->is_root_cache) - return; - - /* - * 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 set_limit_mutex to protect ourselves against this. - */ - mutex_lock(&set_limit_mutex); - for (i = 0; i < memcg_limited_groups_array_size; i++) { - c = s->memcg_params->memcg_caches[i]; - if (!c) - continue; + css_put(&memcg->css); - /* - * 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); - } - mutex_unlock(&set_limit_mutex); + return ret; } -struct create_work { - struct mem_cgroup *memcg; - struct kmem_cache *cachep; - struct work_struct work; -}; - -static void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg) +static struct obj_cgroup *page_objcg(const struct page *page) { - struct kmem_cache *cachep; - struct memcg_cache_params *params; + unsigned long memcg_data = page->memcg_data; - if (!memcg_kmem_is_active(memcg)) - return; + if (mem_cgroup_disabled() || !memcg_data) + return NULL; - mutex_lock(&memcg->slab_caches_mutex); - list_for_each_entry(params, &memcg->memcg_slab_caches, list) { - cachep = memcg_params_to_cache(params); - cachep->memcg_params->dead = true; - schedule_work(&cachep->memcg_params->destroy); - } - mutex_unlock(&memcg->slab_caches_mutex); + VM_BUG_ON_PAGE((memcg_data & OBJEXTS_FLAGS_MASK) != MEMCG_DATA_KMEM, + page); + return (struct obj_cgroup *)(memcg_data - MEMCG_DATA_KMEM); } -static void memcg_create_cache_work_func(struct work_struct *w) +static void page_set_objcg(struct page *page, const struct obj_cgroup *objcg) { - struct create_work *cw; - - cw = container_of(w, struct create_work, work); - memcg_create_kmem_cache(cw->memcg, cw->cachep); - kfree(cw); + page->memcg_data = (unsigned long)objcg | MEMCG_DATA_KMEM; } -/* - * Enqueue the creation of a per-memcg kmem_cache. +/** + * __memcg_kmem_charge_page: charge a kmem page to the current memory cgroup + * @page: page to charge + * @gfp: reclaim mode + * @order: allocation order + * + * Returns 0 on success, an error code on failure. */ -static void __memcg_create_cache_enqueue(struct mem_cgroup *memcg, - struct kmem_cache *cachep) +int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order) { - struct create_work *cw; + struct obj_cgroup *objcg; + int ret = 0; - cw = kmalloc(sizeof(struct create_work), GFP_NOWAIT); - if (cw == NULL) { - css_put(&memcg->css); - return; + objcg = current_obj_cgroup(); + if (objcg) { + ret = obj_cgroup_charge_pages(objcg, gfp, 1 << order); + if (!ret) { + obj_cgroup_get(objcg); + page_set_objcg(page, objcg); + return 0; + } } - - cw->memcg = memcg; - cw->cachep = cachep; - - INIT_WORK(&cw->work, memcg_create_cache_work_func); - schedule_work(&cw->work); + return ret; } -static void memcg_create_cache_enqueue(struct mem_cgroup *memcg, - struct kmem_cache *cachep) -{ - /* - * We need to stop accounting when we kmalloc, because if the - * corresponding kmalloc cache is not yet created, the first allocation - * in __memcg_create_cache_enqueue will recurse. - * - * However, it is better to enclose the whole function. Depending on - * the debugging options enabled, INIT_WORK(), for instance, can - * trigger an allocation. This too, will make us recurse. Because at - * this point we can't allow ourselves back into memcg_kmem_get_cache, - * the safest choice is to do it like this, wrapping the whole function. - */ - memcg_stop_kmem_account(); - __memcg_create_cache_enqueue(memcg, cachep); - memcg_resume_kmem_account(); -} -/* - * Return the kmem_cache we're supposed to use for a slab allocation. - * We try to use the current memcg's version of the cache. - * - * If the cache does not exist yet, if we are the first user of it, - * we either create it immediately, if possible, or create it asynchronously - * in a workqueue. - * In the latter case, we will let the current allocation go through with - * the original cache. - * - * Can't be called in interrupt context or from kernel threads. - * This function needs to be called with rcu_read_lock() held. +/** + * __memcg_kmem_uncharge_page: uncharge a kmem page + * @page: page to uncharge + * @order: allocation order */ -struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep, - gfp_t gfp) +void __memcg_kmem_uncharge_page(struct page *page, int order) { - struct mem_cgroup *memcg; - int idx; - - VM_BUG_ON(!cachep->memcg_params); - VM_BUG_ON(!cachep->memcg_params->is_root_cache); + struct obj_cgroup *objcg = page_objcg(page); + unsigned int nr_pages = 1 << order; - if (!current->mm || current->memcg_kmem_skip_account) - return cachep; - - rcu_read_lock(); - memcg = mem_cgroup_from_task(rcu_dereference(current->mm->owner)); + if (!objcg) + return; - if (!memcg_can_account_kmem(memcg)) - goto out; + obj_cgroup_uncharge_pages(objcg, nr_pages); + page->memcg_data = 0; + obj_cgroup_put(objcg); +} - idx = memcg_cache_id(memcg); +static void __account_obj_stock(struct obj_cgroup *objcg, + struct obj_stock_pcp *stock, int nr, + struct pglist_data *pgdat, enum node_stat_item idx) +{ + int *bytes; /* - * barrier to mare sure we're always seeing the up to date value. The - * code updating memcg_caches will issue a write barrier to match this. + * Save vmstat data in stock and skip vmstat array update unless + * accumulating over a page of vmstat data or when pgdat changes. */ - read_barrier_depends(); - if (likely(cachep->memcg_params->memcg_caches[idx])) { - cachep = cachep->memcg_params->memcg_caches[idx]; - goto out; + if (stock->cached_pgdat != pgdat) { + /* Flush the existing cached vmstat data */ + struct pglist_data *oldpg = stock->cached_pgdat; + + if (stock->nr_slab_reclaimable_b) { + mod_objcg_mlstate(objcg, oldpg, NR_SLAB_RECLAIMABLE_B, + stock->nr_slab_reclaimable_b); + stock->nr_slab_reclaimable_b = 0; + } + if (stock->nr_slab_unreclaimable_b) { + mod_objcg_mlstate(objcg, oldpg, NR_SLAB_UNRECLAIMABLE_B, + stock->nr_slab_unreclaimable_b); + stock->nr_slab_unreclaimable_b = 0; + } + stock->cached_pgdat = pgdat; } - /* The corresponding put will be done in the workqueue. */ - if (!css_tryget(&memcg->css)) - goto out; - rcu_read_unlock(); - + bytes = (idx == NR_SLAB_RECLAIMABLE_B) ? &stock->nr_slab_reclaimable_b + : &stock->nr_slab_unreclaimable_b; /* - * If we are in a safe context (can wait, and not in interrupt - * context), we could be be predictable and return right away. - * This would guarantee that the allocation being performed - * already belongs in the new cache. - * - * However, there are some clashes that can arrive from locking. - * For instance, because we acquire the slab_mutex while doing - * kmem_cache_dup, this means no further allocation could happen - * with the slab_mutex held. - * - * Also, because cache creation issue get_online_cpus(), this - * creates a lock chain: memcg_slab_mutex -> cpu_hotplug_mutex, - * that ends up reversed during cpu hotplug. (cpuset allocates - * a bunch of GFP_KERNEL memory during cpuup). Due to all that, - * better to defer everything. + * Even for large object >= PAGE_SIZE, the vmstat data will still be + * cached locally at least once before pushing it out. */ - memcg_create_cache_enqueue(memcg, cachep); - return cachep; -out: - rcu_read_unlock(); - return cachep; + if (!*bytes) { + *bytes = nr; + nr = 0; + } else { + *bytes += nr; + if (abs(*bytes) > PAGE_SIZE) { + nr = *bytes; + *bytes = 0; + } else { + nr = 0; + } + } + if (nr) + mod_objcg_mlstate(objcg, pgdat, idx, nr); } -EXPORT_SYMBOL(__memcg_kmem_get_cache); -/* - * We need to verify if the allocation against current->mm->owner's memcg is - * possible for the given order. But the page is not allocated yet, so we'll - * need a further commit step to do the final arrangements. - * - * It is possible for the task to switch cgroups in this mean time, so at - * commit time, we can't rely on task conversion any longer. We'll then use - * the handle argument to return to the caller which cgroup we should commit - * against. We could also return the memcg directly and avoid the pointer - * passing, but a boolean return value gives better semantics considering - * the compiled-out case as well. - * - * Returning true means the allocation is possible. - */ -bool -__memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order) +static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes, + struct pglist_data *pgdat, enum node_stat_item idx) { - struct mem_cgroup *memcg; - int ret; - - *_memcg = NULL; - - /* - * Disabling accounting is only relevant for some specific memcg - * internal allocations. Therefore we would initially not have such - * check here, since direct calls to the page allocator that are marked - * with GFP_KMEMCG only happen outside memcg core. We are mostly - * concerned with cache allocations, and by having this test at - * memcg_kmem_get_cache, we are already able to relay the allocation to - * the root cache and bypass the memcg cache altogether. - * - * There is one exception, though: the SLUB allocator does not create - * large order caches, but rather service large kmallocs directly from - * the page allocator. Therefore, the following sequence when backed by - * the SLUB allocator: - * - * memcg_stop_kmem_account(); - * kmalloc(<large_number>) - * memcg_resume_kmem_account(); - * - * would effectively ignore the fact that we should skip accounting, - * since it will drive us directly to this function without passing - * through the cache selector memcg_kmem_get_cache. Such large - * allocations are extremely rare but can happen, for instance, for the - * cache arrays. We bring this test here. - */ - if (!current->mm || current->memcg_kmem_skip_account) - return true; + struct obj_stock_pcp *stock; + bool ret = false; - memcg = try_get_mem_cgroup_from_mm(current->mm); + if (!local_trylock(&obj_stock.lock)) + return ret; - /* - * very rare case described in mem_cgroup_from_task. Unfortunately there - * isn't much we can do without complicating this too much, and it would - * be gfp-dependent anyway. Just let it go - */ - if (unlikely(!memcg)) - return true; + stock = this_cpu_ptr(&obj_stock); + if (objcg == READ_ONCE(stock->cached_objcg) && stock->nr_bytes >= nr_bytes) { + stock->nr_bytes -= nr_bytes; + ret = true; - if (!memcg_can_account_kmem(memcg)) { - css_put(&memcg->css); - return true; + if (pgdat) + __account_obj_stock(objcg, stock, nr_bytes, pgdat, idx); } - ret = memcg_charge_kmem(memcg, gfp, PAGE_SIZE << order); - if (!ret) - *_memcg = memcg; + local_unlock(&obj_stock.lock); - css_put(&memcg->css); - return (ret == 0); + return ret; } -void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, - int order) +static void drain_obj_stock(struct obj_stock_pcp *stock) { - struct page_cgroup *pc; + struct obj_cgroup *old = READ_ONCE(stock->cached_objcg); - VM_BUG_ON(mem_cgroup_is_root(memcg)); - - /* The page allocation failed. Revert */ - if (!page) { - memcg_uncharge_kmem(memcg, PAGE_SIZE << order); + if (!old) return; - } - pc = lookup_page_cgroup(page); - lock_page_cgroup(pc); - pc->mem_cgroup = memcg; - SetPageCgroupUsed(pc); - unlock_page_cgroup(pc); -} + if (stock->nr_bytes) { + unsigned int nr_pages = stock->nr_bytes >> PAGE_SHIFT; + unsigned int nr_bytes = stock->nr_bytes & (PAGE_SIZE - 1); -void __memcg_kmem_uncharge_pages(struct page *page, int order) -{ - struct mem_cgroup *memcg = NULL; - struct page_cgroup *pc; + if (nr_pages) { + struct mem_cgroup *memcg; + memcg = get_mem_cgroup_from_objcg(old); - pc = lookup_page_cgroup(page); - /* - * Fast unlocked return. Theoretically might have changed, have to - * check again after locking. - */ - if (!PageCgroupUsed(pc)) - return; + mod_memcg_state(memcg, MEMCG_KMEM, -nr_pages); + memcg1_account_kmem(memcg, -nr_pages); + if (!mem_cgroup_is_root(memcg)) + memcg_uncharge(memcg, nr_pages); - lock_page_cgroup(pc); - if (PageCgroupUsed(pc)) { - memcg = pc->mem_cgroup; - ClearPageCgroupUsed(pc); + css_put(&memcg->css); + } + + /* + * The leftover is flushed to the centralized per-memcg value. + * On the next attempt to refill obj stock it will be moved + * to a per-cpu stock (probably, on an other CPU), see + * refill_obj_stock(). + * + * How often it's flushed is a trade-off between the memory + * limit enforcement accuracy and potential CPU contention, + * so it might be changed in the future. + */ + atomic_add(nr_bytes, &old->nr_charged_bytes); + stock->nr_bytes = 0; } - unlock_page_cgroup(pc); /* - * We trust that only if there is a memcg associated with the page, it - * is a valid allocation + * Flush the vmstat data in current stock */ - if (!memcg) - return; + if (stock->nr_slab_reclaimable_b || stock->nr_slab_unreclaimable_b) { + if (stock->nr_slab_reclaimable_b) { + mod_objcg_mlstate(old, stock->cached_pgdat, + NR_SLAB_RECLAIMABLE_B, + stock->nr_slab_reclaimable_b); + stock->nr_slab_reclaimable_b = 0; + } + if (stock->nr_slab_unreclaimable_b) { + mod_objcg_mlstate(old, stock->cached_pgdat, + NR_SLAB_UNRECLAIMABLE_B, + stock->nr_slab_unreclaimable_b); + stock->nr_slab_unreclaimable_b = 0; + } + stock->cached_pgdat = NULL; + } - VM_BUG_ON(mem_cgroup_is_root(memcg)); - memcg_uncharge_kmem(memcg, PAGE_SIZE << order); + WRITE_ONCE(stock->cached_objcg, NULL); + obj_cgroup_put(old); } -#else -static inline void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg) -{ -} -#endif /* CONFIG_MEMCG_KMEM */ - -#ifdef CONFIG_TRANSPARENT_HUGEPAGE -#define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION) -/* - * Because tail pages are not marked as "used", set it. We're under - * zone->lru_lock, 'splitting on pmd' and compound_lock. - * charge/uncharge will be never happen and move_account() is done under - * compound_lock(), so we don't have to take care of races. - */ -void mem_cgroup_split_huge_fixup(struct page *head) +static bool obj_stock_flush_required(struct obj_stock_pcp *stock, + struct mem_cgroup *root_memcg) { - struct page_cgroup *head_pc = lookup_page_cgroup(head); - struct page_cgroup *pc; + struct obj_cgroup *objcg = READ_ONCE(stock->cached_objcg); struct mem_cgroup *memcg; - int i; - - if (mem_cgroup_disabled()) - return; + bool flush = false; - memcg = head_pc->mem_cgroup; - for (i = 1; i < HPAGE_PMD_NR; i++) { - pc = head_pc + i; - pc->mem_cgroup = memcg; - smp_wmb();/* see __commit_charge() */ - pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT; + rcu_read_lock(); + if (objcg) { + memcg = obj_cgroup_memcg(objcg); + if (memcg && mem_cgroup_is_descendant(memcg, root_memcg)) + flush = true; } - __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], - HPAGE_PMD_NR); + rcu_read_unlock(); + + return flush; } -#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ -/** - * mem_cgroup_move_account - move account of the page - * @page: the page - * @nr_pages: number of regular pages (>1 for huge pages) - * @pc: page_cgroup of the page. - * @from: mem_cgroup which the page is moved from. - * @to: mem_cgroup which the page is moved to. @from != @to. - * - * The caller must confirm following. - * - page is not on LRU (isolate_page() is useful.) - * - compound_lock is held when nr_pages > 1 - * - * This function doesn't do "charge" to new cgroup and doesn't do "uncharge" - * from old cgroup. - */ -static int mem_cgroup_move_account(struct page *page, - unsigned int nr_pages, - struct page_cgroup *pc, - struct mem_cgroup *from, - struct mem_cgroup *to) +static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes, + bool allow_uncharge, int nr_acct, struct pglist_data *pgdat, + enum node_stat_item idx) { - unsigned long flags; - int ret; - bool anon = PageAnon(page); + struct obj_stock_pcp *stock; + unsigned int nr_pages = 0; - VM_BUG_ON(from == to); - VM_BUG_ON(PageLRU(page)); - /* - * The page is isolated from LRU. So, collapse function - * will not handle this page. But page splitting can happen. - * Do this check under compound_page_lock(). The caller should - * hold it. - */ - ret = -EBUSY; - if (nr_pages > 1 && !PageTransHuge(page)) + if (!local_trylock(&obj_stock.lock)) { + if (pgdat) + mod_objcg_mlstate(objcg, pgdat, idx, nr_bytes); + nr_pages = nr_bytes >> PAGE_SHIFT; + nr_bytes = nr_bytes & (PAGE_SIZE - 1); + atomic_add(nr_bytes, &objcg->nr_charged_bytes); goto out; + } - lock_page_cgroup(pc); + stock = this_cpu_ptr(&obj_stock); + if (READ_ONCE(stock->cached_objcg) != objcg) { /* reset if necessary */ + drain_obj_stock(stock); + obj_cgroup_get(objcg); + stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes) + ? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0; + WRITE_ONCE(stock->cached_objcg, objcg); - ret = -EINVAL; - if (!PageCgroupUsed(pc) || pc->mem_cgroup != from) - goto unlock; + allow_uncharge = true; /* Allow uncharge when objcg changes */ + } + stock->nr_bytes += nr_bytes; - move_lock_mem_cgroup(from, &flags); + if (pgdat) + __account_obj_stock(objcg, stock, nr_acct, pgdat, idx); - if (!anon && page_mapped(page)) { - /* Update mapped_file data for mem_cgroup */ - preempt_disable(); - __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); - __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); - preempt_enable(); + if (allow_uncharge && (stock->nr_bytes > PAGE_SIZE)) { + nr_pages = stock->nr_bytes >> PAGE_SHIFT; + stock->nr_bytes &= (PAGE_SIZE - 1); } - mem_cgroup_charge_statistics(from, page, anon, -nr_pages); - /* caller should have done css_get */ - pc->mem_cgroup = to; - mem_cgroup_charge_statistics(to, page, anon, nr_pages); - move_unlock_mem_cgroup(from, &flags); - ret = 0; -unlock: - unlock_page_cgroup(pc); - /* - * check events - */ - memcg_check_events(to, page); - memcg_check_events(from, page); + local_unlock(&obj_stock.lock); out: - return ret; + if (nr_pages) + obj_cgroup_uncharge_pages(objcg, nr_pages); } -/** - * mem_cgroup_move_parent - moves page to the parent group - * @page: the page to move - * @pc: page_cgroup of the page - * @child: page's cgroup - * - * move charges to its parent or the root cgroup if the group has no - * parent (aka use_hierarchy==0). - * Although this might fail (get_page_unless_zero, isolate_lru_page or - * mem_cgroup_move_account fails) the failure is always temporary and - * it signals a race with a page removal/uncharge or migration. In the - * first case the page is on the way out and it will vanish from the LRU - * on the next attempt and the call should be retried later. - * Isolation from the LRU fails only if page has been isolated from - * the LRU since we looked at it and that usually means either global - * reclaim or migration going on. The page will either get back to the - * LRU or vanish. - * Finaly mem_cgroup_move_account fails only if the page got uncharged - * (!PageCgroupUsed) or moved to a different group. The page will - * disappear in the next attempt. - */ -static int mem_cgroup_move_parent(struct page *page, - struct page_cgroup *pc, - struct mem_cgroup *child) +static int obj_cgroup_charge_account(struct obj_cgroup *objcg, gfp_t gfp, size_t size, + struct pglist_data *pgdat, enum node_stat_item idx) { - struct mem_cgroup *parent; - unsigned int nr_pages; - unsigned long uninitialized_var(flags); + unsigned int nr_pages, nr_bytes; int ret; - VM_BUG_ON(mem_cgroup_is_root(child)); - - ret = -EBUSY; - if (!get_page_unless_zero(page)) - goto out; - if (isolate_lru_page(page)) - goto put; - - nr_pages = hpage_nr_pages(page); + if (likely(consume_obj_stock(objcg, size, pgdat, idx))) + return 0; - parent = parent_mem_cgroup(child); /* - * If no parent, move charges to root cgroup. + * In theory, objcg->nr_charged_bytes can have enough + * pre-charged bytes to satisfy the allocation. However, + * flushing objcg->nr_charged_bytes requires two atomic + * operations, and objcg->nr_charged_bytes can't be big. + * The shared objcg->nr_charged_bytes can also become a + * performance bottleneck if all tasks of the same memcg are + * trying to update it. So it's better to ignore it and try + * grab some new pages. The stock's nr_bytes will be flushed to + * objcg->nr_charged_bytes later on when objcg changes. + * + * The stock's nr_bytes may contain enough pre-charged bytes + * to allow one less page from being charged, but we can't rely + * on the pre-charged bytes not being changed outside of + * consume_obj_stock() or refill_obj_stock(). So ignore those + * pre-charged bytes as well when charging pages. To avoid a + * page uncharge right after a page charge, we set the + * allow_uncharge flag to false when calling refill_obj_stock() + * to temporarily allow the pre-charged bytes to exceed the page + * size limit. The maximum reachable value of the pre-charged + * bytes is (sizeof(object) + PAGE_SIZE - 2) if there is no data + * race. */ - if (!parent) - parent = root_mem_cgroup; + nr_pages = size >> PAGE_SHIFT; + nr_bytes = size & (PAGE_SIZE - 1); - if (nr_pages > 1) { - VM_BUG_ON(!PageTransHuge(page)); - flags = compound_lock_irqsave(page); - } + if (nr_bytes) + nr_pages += 1; - ret = mem_cgroup_move_account(page, nr_pages, - pc, child, parent); - if (!ret) - __mem_cgroup_cancel_local_charge(child, nr_pages); + ret = obj_cgroup_charge_pages(objcg, gfp, nr_pages); + if (!ret && (nr_bytes || pgdat)) + refill_obj_stock(objcg, nr_bytes ? PAGE_SIZE - nr_bytes : 0, + false, size, pgdat, idx); - if (nr_pages > 1) - compound_unlock_irqrestore(page, flags); - putback_lru_page(page); -put: - put_page(page); -out: return ret; } -/* - * Charge the memory controller for page usage. - * Return - * 0 if the charge was successful - * < 0 if the cgroup is over its limit - */ -static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, - gfp_t gfp_mask, enum charge_type ctype) +int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size) { - struct mem_cgroup *memcg = NULL; - unsigned int nr_pages = 1; - bool oom = true; - int ret; - - if (PageTransHuge(page)) { - nr_pages <<= compound_order(page); - VM_BUG_ON(!PageTransHuge(page)); - /* - * Never OOM-kill a process for a huge page. The - * fault handler will fall back to regular pages. - */ - oom = false; - } - - ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &memcg, oom); - if (ret == -ENOMEM) - return ret; - __mem_cgroup_commit_charge(memcg, page, nr_pages, ctype, false); - return 0; + return obj_cgroup_charge_account(objcg, gfp, size, NULL, 0); } -int mem_cgroup_newpage_charge(struct page *page, - struct mm_struct *mm, gfp_t gfp_mask) +void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size) { - if (mem_cgroup_disabled()) - return 0; - VM_BUG_ON(page_mapped(page)); - VM_BUG_ON(page->mapping && !PageAnon(page)); - VM_BUG_ON(!mm); - return mem_cgroup_charge_common(page, mm, gfp_mask, - MEM_CGROUP_CHARGE_TYPE_ANON); + refill_obj_stock(objcg, size, true, 0, NULL, 0); } -/* - * While swap-in, try_charge -> commit or cancel, the page is locked. - * And when try_charge() successfully returns, one refcnt to memcg without - * struct page_cgroup is acquired. This refcnt will be consumed by - * "commit()" or removed by "cancel()" - */ -static int __mem_cgroup_try_charge_swapin(struct mm_struct *mm, - struct page *page, - gfp_t mask, - struct mem_cgroup **memcgp) +static inline size_t obj_full_size(struct kmem_cache *s) { - struct mem_cgroup *memcg; - struct page_cgroup *pc; - int ret; - - pc = lookup_page_cgroup(page); /* - * Every swap fault against a single page tries to charge the - * page, bail as early as possible. shmem_unuse() encounters - * already charged pages, too. The USED bit is protected by - * the page lock, which serializes swap cache removal, which - * in turn serializes uncharging. + * For each accounted object there is an extra space which is used + * to store obj_cgroup membership. Charge it too. */ - if (PageCgroupUsed(pc)) - return 0; - if (!do_swap_account) - goto charge_cur_mm; - memcg = try_get_mem_cgroup_from_page(page); - if (!memcg) - goto charge_cur_mm; - *memcgp = memcg; - ret = __mem_cgroup_try_charge(NULL, mask, 1, memcgp, true); - css_put(&memcg->css); - if (ret == -EINTR) - ret = 0; - return ret; -charge_cur_mm: - ret = __mem_cgroup_try_charge(mm, mask, 1, memcgp, true); - if (ret == -EINTR) - ret = 0; - return ret; + return s->size + sizeof(struct obj_cgroup *); } -int mem_cgroup_try_charge_swapin(struct mm_struct *mm, struct page *page, - gfp_t gfp_mask, struct mem_cgroup **memcgp) +bool __memcg_slab_post_alloc_hook(struct kmem_cache *s, struct list_lru *lru, + gfp_t flags, size_t size, void **p) { - *memcgp = NULL; - if (mem_cgroup_disabled()) - return 0; + struct obj_cgroup *objcg; + struct slab *slab; + unsigned long off; + size_t i; + /* - * A racing thread's fault, or swapoff, may have already - * updated the pte, and even removed page from swap cache: in - * those cases unuse_pte()'s pte_same() test will fail; but - * there's also a KSM case which does need to charge the page. + * The obtained objcg pointer is safe to use within the current scope, + * defined by current task or set_active_memcg() pair. + * obj_cgroup_get() is used to get a permanent reference. */ - if (!PageSwapCache(page)) { - int ret; + objcg = current_obj_cgroup(); + if (!objcg) + return true; - ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, memcgp, true); - if (ret == -EINTR) - ret = 0; - return ret; - } - return __mem_cgroup_try_charge_swapin(mm, page, gfp_mask, memcgp); -} + /* + * slab_alloc_node() avoids the NULL check, so we might be called with a + * single NULL object. kmem_cache_alloc_bulk() aborts if it can't fill + * the whole requested size. + * return success as there's nothing to free back + */ + if (unlikely(*p == NULL)) + return true; -void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg) -{ - if (mem_cgroup_disabled()) - return; - if (!memcg) - return; - __mem_cgroup_cancel_charge(memcg, 1); -} + flags &= gfp_allowed_mask; -static void -__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg, - enum charge_type ctype) -{ - if (mem_cgroup_disabled()) - return; - if (!memcg) - return; + if (lru) { + int ret; + struct mem_cgroup *memcg; - __mem_cgroup_commit_charge(memcg, page, 1, ctype, true); - /* - * Now swap is on-memory. This means this page may be - * counted both as mem and swap....double count. - * Fix it by uncharging from memsw. Basically, this SwapCache is stable - * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page() - * may call delete_from_swap_cache() before reach here. - */ - if (do_swap_account && PageSwapCache(page)) { - swp_entry_t ent = {.val = page_private(page)}; - mem_cgroup_uncharge_swap(ent); + memcg = get_mem_cgroup_from_objcg(objcg); + ret = memcg_list_lru_alloc(memcg, lru, flags); + css_put(&memcg->css); + + if (ret) + return false; } -} -void mem_cgroup_commit_charge_swapin(struct page *page, - struct mem_cgroup *memcg) -{ - __mem_cgroup_commit_charge_swapin(page, memcg, - MEM_CGROUP_CHARGE_TYPE_ANON); -} + for (i = 0; i < size; i++) { + slab = virt_to_slab(p[i]); -int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, - gfp_t gfp_mask) -{ - struct mem_cgroup *memcg = NULL; - enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE; - int ret; + if (!slab_obj_exts(slab) && + alloc_slab_obj_exts(slab, s, flags, false)) { + continue; + } - if (mem_cgroup_disabled()) - return 0; - if (PageCompound(page)) - return 0; + /* + * if we fail and size is 1, memcg_alloc_abort_single() will + * just free the object, which is ok as we have not assigned + * objcg to its obj_ext yet + * + * for larger sizes, kmem_cache_free_bulk() will uncharge + * any objects that were already charged and obj_ext assigned + * + * TODO: we could batch this until slab_pgdat(slab) changes + * between iterations, with a more complicated undo + */ + if (obj_cgroup_charge_account(objcg, flags, obj_full_size(s), + slab_pgdat(slab), cache_vmstat_idx(s))) + return false; - if (!PageSwapCache(page)) - ret = mem_cgroup_charge_common(page, mm, gfp_mask, type); - else { /* page is swapcache/shmem */ - ret = __mem_cgroup_try_charge_swapin(mm, page, - gfp_mask, &memcg); - if (!ret) - __mem_cgroup_commit_charge_swapin(page, memcg, type); + off = obj_to_index(s, slab, p[i]); + obj_cgroup_get(objcg); + slab_obj_exts(slab)[off].objcg = objcg; } - return ret; + + return true; } -static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg, - unsigned int nr_pages, - const enum charge_type ctype) +void __memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab, + void **p, int objects, struct slabobj_ext *obj_exts) { - struct memcg_batch_info *batch = NULL; - bool uncharge_memsw = true; - - /* If swapout, usage of swap doesn't decrease */ - if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) - uncharge_memsw = false; - - batch = ¤t->memcg_batch; - /* - * In usual, we do css_get() when we remember memcg pointer. - * But in this case, we keep res->usage until end of a series of - * uncharges. Then, it's ok to ignore memcg's refcnt. - */ - if (!batch->memcg) - batch->memcg = memcg; - /* - * do_batch > 0 when unmapping pages or inode invalidate/truncate. - * In those cases, all pages freed continuously can be expected to be in - * the same cgroup and we have chance to coalesce uncharges. - * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE) - * because we want to do uncharge as soon as possible. - */ + size_t obj_size = obj_full_size(s); - if (!batch->do_batch || test_thread_flag(TIF_MEMDIE)) - goto direct_uncharge; + for (int i = 0; i < objects; i++) { + struct obj_cgroup *objcg; + unsigned int off; - if (nr_pages > 1) - goto direct_uncharge; + off = obj_to_index(s, slab, p[i]); + objcg = obj_exts[off].objcg; + if (!objcg) + continue; - /* - * In typical case, batch->memcg == mem. This means we can - * merge a series of uncharges to an uncharge of res_counter. - * If not, we uncharge res_counter ony by one. - */ - if (batch->memcg != memcg) - goto direct_uncharge; - /* remember freed charge and uncharge it later */ - batch->nr_pages++; - if (uncharge_memsw) - batch->memsw_nr_pages++; - return; -direct_uncharge: - res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE); - if (uncharge_memsw) - res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE); - if (unlikely(batch->memcg != memcg)) - memcg_oom_recover(memcg); + obj_exts[off].objcg = NULL; + refill_obj_stock(objcg, obj_size, true, -obj_size, + slab_pgdat(slab), cache_vmstat_idx(s)); + obj_cgroup_put(objcg); + } } /* - * uncharge if !page_mapped(page) + * The objcg is only set on the first page, so transfer it to all the + * other pages. */ -static struct mem_cgroup * -__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype, - bool end_migration) +void split_page_memcg(struct page *page, unsigned order) { - struct mem_cgroup *memcg = NULL; - unsigned int nr_pages = 1; - struct page_cgroup *pc; - bool anon; + struct obj_cgroup *objcg = page_objcg(page); + unsigned int i, nr = 1 << order; - if (mem_cgroup_disabled()) - return NULL; + if (!objcg) + return; - if (PageTransHuge(page)) { - nr_pages <<= compound_order(page); - VM_BUG_ON(!PageTransHuge(page)); - } - /* - * Check if our page_cgroup is valid - */ - pc = lookup_page_cgroup(page); - if (unlikely(!PageCgroupUsed(pc))) - return NULL; + for (i = 1; i < nr; i++) + page_set_objcg(&page[i], objcg); - lock_page_cgroup(pc); + obj_cgroup_get_many(objcg, nr - 1); +} - memcg = pc->mem_cgroup; +void folio_split_memcg_refs(struct folio *folio, unsigned old_order, + unsigned new_order) +{ + unsigned new_refs; - if (!PageCgroupUsed(pc)) - goto unlock_out; + if (mem_cgroup_disabled() || !folio_memcg_charged(folio)) + return; - anon = PageAnon(page); + new_refs = (1 << (old_order - new_order)) - 1; + css_get_many(&__folio_memcg(folio)->css, new_refs); +} - switch (ctype) { - case MEM_CGROUP_CHARGE_TYPE_ANON: - /* - * Generally PageAnon tells if it's the anon statistics to be - * updated; but sometimes e.g. mem_cgroup_uncharge_page() is - * used before page reached the stage of being marked PageAnon. - */ - anon = true; - /* fallthrough */ - case MEM_CGROUP_CHARGE_TYPE_DROP: - /* See mem_cgroup_prepare_migration() */ - if (page_mapped(page)) - goto unlock_out; +unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) +{ + unsigned long val; + + if (mem_cgroup_is_root(memcg)) { /* - * Pages under migration may not be uncharged. But - * end_migration() /must/ be the one uncharging the - * unused post-migration page and so it has to call - * here with the migration bit still set. See the - * res_counter handling below. + * Approximate root's usage from global state. This isn't + * perfect, but the root usage was always an approximation. */ - if (!end_migration && PageCgroupMigration(pc)) - goto unlock_out; - break; - case MEM_CGROUP_CHARGE_TYPE_SWAPOUT: - if (!PageAnon(page)) { /* Shared memory */ - if (page->mapping && !page_is_file_cache(page)) - goto unlock_out; - } else if (page_mapped(page)) /* Anon */ - goto unlock_out; - break; - default: - break; + val = global_node_page_state(NR_FILE_PAGES) + + global_node_page_state(NR_ANON_MAPPED); + if (swap) + val += total_swap_pages - get_nr_swap_pages(); + } else { + if (!swap) + val = page_counter_read(&memcg->memory); + else + val = page_counter_read(&memcg->memsw); } + return val; +} - mem_cgroup_charge_statistics(memcg, page, anon, -nr_pages); +static int memcg_online_kmem(struct mem_cgroup *memcg) +{ + struct obj_cgroup *objcg; - ClearPageCgroupUsed(pc); - /* - * pc->mem_cgroup is not cleared here. It will be accessed when it's - * freed from LRU. This is safe because uncharged page is expected not - * to be reused (freed soon). Exception is SwapCache, it's handled by - * special functions. - */ + if (mem_cgroup_kmem_disabled()) + return 0; - unlock_page_cgroup(pc); - /* - * even after unlock, we have memcg->res.usage here and this memcg - * will never be freed, so it's safe to call css_get(). - */ - memcg_check_events(memcg, page); - if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) { - mem_cgroup_swap_statistics(memcg, true); - css_get(&memcg->css); - } - /* - * Migration does not charge the res_counter for the - * replacement page, so leave it alone when phasing out the - * page that is unused after the migration. - */ - if (!end_migration && !mem_cgroup_is_root(memcg)) - mem_cgroup_do_uncharge(memcg, nr_pages, ctype); + if (unlikely(mem_cgroup_is_root(memcg))) + return 0; - return memcg; + objcg = obj_cgroup_alloc(); + if (!objcg) + return -ENOMEM; -unlock_out: - unlock_page_cgroup(pc); - return NULL; + objcg->memcg = memcg; + rcu_assign_pointer(memcg->objcg, objcg); + obj_cgroup_get(objcg); + memcg->orig_objcg = objcg; + + static_branch_enable(&memcg_kmem_online_key); + + memcg->kmemcg_id = memcg->id.id; + + return 0; } -void mem_cgroup_uncharge_page(struct page *page) +static void memcg_offline_kmem(struct mem_cgroup *memcg) { - /* early check. */ - if (page_mapped(page)) + struct mem_cgroup *parent; + + if (mem_cgroup_kmem_disabled()) + return; + + if (unlikely(mem_cgroup_is_root(memcg))) return; - VM_BUG_ON(page->mapping && !PageAnon(page)); + + parent = parent_mem_cgroup(memcg); + if (!parent) + parent = root_mem_cgroup; + + memcg_reparent_list_lrus(memcg, parent); + /* - * If the page is in swap cache, uncharge should be deferred - * to the swap path, which also properly accounts swap usage - * and handles memcg lifetime. - * - * Note that this check is not stable and reclaim may add the - * page to swap cache at any time after this. However, if the - * page is not in swap cache by the time page->mapcount hits - * 0, there won't be any page table references to the swap - * slot, and reclaim will free it and not actually write the - * page to disk. + * Objcg's reparenting must be after list_lru's, make sure list_lru + * helpers won't use parent's list_lru until child is drained. */ - if (PageSwapCache(page)) - return; - __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_ANON, false); + memcg_reparent_objcgs(memcg, parent); } -void mem_cgroup_uncharge_cache_page(struct page *page) -{ - VM_BUG_ON(page_mapped(page)); - VM_BUG_ON(page->mapping); - __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false); -} +#ifdef CONFIG_CGROUP_WRITEBACK -/* - * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate. - * In that cases, pages are freed continuously and we can expect pages - * are in the same memcg. All these calls itself limits the number of - * pages freed at once, then uncharge_start/end() is called properly. - * This may be called prural(2) times in a context, - */ +#include <trace/events/writeback.h> -void mem_cgroup_uncharge_start(void) +static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp) { - current->memcg_batch.do_batch++; - /* We can do nest. */ - if (current->memcg_batch.do_batch == 1) { - current->memcg_batch.memcg = NULL; - current->memcg_batch.nr_pages = 0; - current->memcg_batch.memsw_nr_pages = 0; - } + return wb_domain_init(&memcg->cgwb_domain, gfp); } -void mem_cgroup_uncharge_end(void) +static void memcg_wb_domain_exit(struct mem_cgroup *memcg) { - struct memcg_batch_info *batch = ¤t->memcg_batch; - - if (!batch->do_batch) - return; - - batch->do_batch--; - if (batch->do_batch) /* If stacked, do nothing. */ - return; - - if (!batch->memcg) - return; - /* - * This "batch->memcg" is valid without any css_get/put etc... - * bacause we hide charges behind us. - */ - if (batch->nr_pages) - res_counter_uncharge(&batch->memcg->res, - batch->nr_pages * PAGE_SIZE); - if (batch->memsw_nr_pages) - res_counter_uncharge(&batch->memcg->memsw, - batch->memsw_nr_pages * PAGE_SIZE); - memcg_oom_recover(batch->memcg); - /* forget this pointer (for sanity check) */ - batch->memcg = NULL; + wb_domain_exit(&memcg->cgwb_domain); } -#ifdef CONFIG_SWAP -/* - * called after __delete_from_swap_cache() and drop "page" account. - * memcg information is recorded to swap_cgroup of "ent" - */ -void -mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) +static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg) { - struct mem_cgroup *memcg; - int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT; + wb_domain_size_changed(&memcg->cgwb_domain); +} - if (!swapout) /* this was a swap cache but the swap is unused ! */ - ctype = MEM_CGROUP_CHARGE_TYPE_DROP; +struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css); - memcg = __mem_cgroup_uncharge_common(page, ctype, false); + if (!memcg->css.parent) + return NULL; - /* - * record memcg information, if swapout && memcg != NULL, - * css_get() was called in uncharge(). - */ - if (do_swap_account && swapout && memcg) - swap_cgroup_record(ent, css_id(&memcg->css)); + return &memcg->cgwb_domain; } -#endif -#ifdef CONFIG_MEMCG_SWAP -/* - * called from swap_entry_free(). remove record in swap_cgroup and - * uncharge "memsw" account. +/** + * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg + * @wb: bdi_writeback in question + * @pfilepages: out parameter for number of file pages + * @pheadroom: out parameter for number of allocatable pages according to memcg + * @pdirty: out parameter for number of dirty pages + * @pwriteback: out parameter for number of pages under writeback + * + * Determine the numbers of file, headroom, dirty, and writeback pages in + * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom + * is a bit more involved. + * + * A memcg's headroom is "min(max, high) - used". In the hierarchy, the + * headroom is calculated as the lowest headroom of itself and the + * ancestors. Note that this doesn't consider the actual amount of + * available memory in the system. The caller should further cap + * *@pheadroom accordingly. */ -void mem_cgroup_uncharge_swap(swp_entry_t ent) +void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages, + unsigned long *pheadroom, unsigned long *pdirty, + unsigned long *pwriteback) { - struct mem_cgroup *memcg; - unsigned short id; + struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css); + struct mem_cgroup *parent; - if (!do_swap_account) - return; + mem_cgroup_flush_stats_ratelimited(memcg); - id = swap_cgroup_record(ent, 0); - rcu_read_lock(); - memcg = mem_cgroup_lookup(id); - if (memcg) { - /* - * We uncharge this because swap is freed. - * This memcg can be obsolete one. We avoid calling css_tryget - */ - if (!mem_cgroup_is_root(memcg)) - res_counter_uncharge(&memcg->memsw, PAGE_SIZE); - mem_cgroup_swap_statistics(memcg, false); - css_put(&memcg->css); + *pdirty = memcg_page_state(memcg, NR_FILE_DIRTY); + *pwriteback = memcg_page_state(memcg, NR_WRITEBACK); + *pfilepages = memcg_page_state(memcg, NR_INACTIVE_FILE) + + memcg_page_state(memcg, NR_ACTIVE_FILE); + + *pheadroom = PAGE_COUNTER_MAX; + while ((parent = parent_mem_cgroup(memcg))) { + unsigned long ceiling = min(READ_ONCE(memcg->memory.max), + READ_ONCE(memcg->memory.high)); + unsigned long used = page_counter_read(&memcg->memory); + + *pheadroom = min(*pheadroom, ceiling - min(ceiling, used)); + memcg = parent; } - rcu_read_unlock(); } -/** - * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record. - * @entry: swap entry to be moved - * @from: mem_cgroup which the entry is moved from - * @to: mem_cgroup which the entry is moved to +/* + * Foreign dirty flushing + * + * There's an inherent mismatch between memcg and writeback. The former + * tracks ownership per-page while the latter per-inode. This was a + * deliberate design decision because honoring per-page ownership in the + * writeback path is complicated, may lead to higher CPU and IO overheads + * and deemed unnecessary given that write-sharing an inode across + * different cgroups isn't a common use-case. + * + * Combined with inode majority-writer ownership switching, this works well + * enough in most cases but there are some pathological cases. For + * example, let's say there are two cgroups A and B which keep writing to + * different but confined parts of the same inode. B owns the inode and + * A's memory is limited far below B's. A's dirty ratio can rise enough to + * trigger balance_dirty_pages() sleeps but B's can be low enough to avoid + * triggering background writeback. A will be slowed down without a way to + * make writeback of the dirty pages happen. + * + * Conditions like the above can lead to a cgroup getting repeatedly and + * severely throttled after making some progress after each + * dirty_expire_interval while the underlying IO device is almost + * completely idle. * - * It succeeds only when the swap_cgroup's record for this entry is the same - * as the mem_cgroup's id of @from. + * Solving this problem completely requires matching the ownership tracking + * granularities between memcg and writeback in either direction. However, + * the more egregious behaviors can be avoided by simply remembering the + * most recent foreign dirtying events and initiating remote flushes on + * them when local writeback isn't enough to keep the memory clean enough. * - * Returns 0 on success, -EINVAL on failure. + * The following two functions implement such mechanism. When a foreign + * page - a page whose memcg and writeback ownerships don't match - is + * dirtied, mem_cgroup_track_foreign_dirty() records the inode owning + * bdi_writeback on the page owning memcg. When balance_dirty_pages() + * decides that the memcg needs to sleep due to high dirty ratio, it calls + * mem_cgroup_flush_foreign() which queues writeback on the recorded + * foreign bdi_writebacks which haven't expired. Both the numbers of + * recorded bdi_writebacks and concurrent in-flight foreign writebacks are + * limited to MEMCG_CGWB_FRN_CNT. * - * The caller must have charged to @to, IOW, called res_counter_charge() about - * both res and memsw, and called css_get(). + * The mechanism only remembers IDs and doesn't hold any object references. + * As being wrong occasionally doesn't matter, updates and accesses to the + * records are lockless and racy. */ -static int mem_cgroup_move_swap_account(swp_entry_t entry, - struct mem_cgroup *from, struct mem_cgroup *to) -{ - unsigned short old_id, new_id; +void mem_cgroup_track_foreign_dirty_slowpath(struct folio *folio, + struct bdi_writeback *wb) +{ + struct mem_cgroup *memcg = folio_memcg(folio); + struct memcg_cgwb_frn *frn; + u64 now = get_jiffies_64(); + u64 oldest_at = now; + int oldest = -1; + int i; + + trace_track_foreign_dirty(folio, wb); - old_id = css_id(&from->css); - new_id = css_id(&to->css); + /* + * Pick the slot to use. If there is already a slot for @wb, keep + * using it. If not replace the oldest one which isn't being + * written out. + */ + for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) { + frn = &memcg->cgwb_frn[i]; + if (frn->bdi_id == wb->bdi->id && + frn->memcg_id == wb->memcg_css->id) + break; + if (time_before64(frn->at, oldest_at) && + atomic_read(&frn->done.cnt) == 1) { + oldest = i; + oldest_at = frn->at; + } + } - if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { - mem_cgroup_swap_statistics(from, false); - mem_cgroup_swap_statistics(to, true); + if (i < MEMCG_CGWB_FRN_CNT) { /* - * This function is only called from task migration context now. - * It postpones res_counter and refcount handling till the end - * of task migration(mem_cgroup_clear_mc()) for performance - * improvement. But we cannot postpone css_get(to) because if - * the process that has been moved to @to does swap-in, the - * refcount of @to might be decreased to 0. - * - * We are in attach() phase, so the cgroup is guaranteed to be - * alive, so we can just call css_get(). + * Re-using an existing one. Update timestamp lazily to + * avoid making the cacheline hot. We want them to be + * reasonably up-to-date and significantly shorter than + * dirty_expire_interval as that's what expires the record. + * Use the shorter of 1s and dirty_expire_interval / 8. */ - css_get(&to->css); - return 0; + unsigned long update_intv = + min_t(unsigned long, HZ, + msecs_to_jiffies(dirty_expire_interval * 10) / 8); + + if (time_before64(frn->at, now - update_intv)) + frn->at = now; + } else if (oldest >= 0) { + /* replace the oldest free one */ + frn = &memcg->cgwb_frn[oldest]; + frn->bdi_id = wb->bdi->id; + frn->memcg_id = wb->memcg_css->id; + frn->at = now; } - return -EINVAL; -} -#else -static inline int mem_cgroup_move_swap_account(swp_entry_t entry, - struct mem_cgroup *from, struct mem_cgroup *to) -{ - return -EINVAL; } -#endif -/* - * Before starting migration, account PAGE_SIZE to mem_cgroup that the old - * page belongs to. - */ -void mem_cgroup_prepare_migration(struct page *page, struct page *newpage, - struct mem_cgroup **memcgp) +/* issue foreign writeback flushes for recorded foreign dirtying events */ +void mem_cgroup_flush_foreign(struct bdi_writeback *wb) { - struct mem_cgroup *memcg = NULL; - unsigned int nr_pages = 1; - struct page_cgroup *pc; - enum charge_type ctype; - - *memcgp = NULL; - - if (mem_cgroup_disabled()) - return; + struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css); + unsigned long intv = msecs_to_jiffies(dirty_expire_interval * 10); + u64 now = jiffies_64; + int i; - if (PageTransHuge(page)) - nr_pages <<= compound_order(page); + for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) { + struct memcg_cgwb_frn *frn = &memcg->cgwb_frn[i]; - pc = lookup_page_cgroup(page); - lock_page_cgroup(pc); - if (PageCgroupUsed(pc)) { - memcg = pc->mem_cgroup; - css_get(&memcg->css); /* - * At migrating an anonymous page, its mapcount goes down - * to 0 and uncharge() will be called. But, even if it's fully - * unmapped, migration may fail and this page has to be - * charged again. We set MIGRATION flag here and delay uncharge - * until end_migration() is called - * - * Corner Case Thinking - * A) - * When the old page was mapped as Anon and it's unmap-and-freed - * while migration was ongoing. - * If unmap finds the old page, uncharge() of it will be delayed - * until end_migration(). If unmap finds a new page, it's - * uncharged when it make mapcount to be 1->0. If unmap code - * finds swap_migration_entry, the new page will not be mapped - * and end_migration() will find it(mapcount==0). - * - * B) - * When the old page was mapped but migraion fails, the kernel - * remaps it. A charge for it is kept by MIGRATION flag even - * if mapcount goes down to 0. We can do remap successfully - * without charging it again. - * - * C) - * The "old" page is under lock_page() until the end of - * migration, so, the old page itself will not be swapped-out. - * If the new page is swapped out before end_migraton, our - * hook to usual swap-out path will catch the event. + * If the record is older than dirty_expire_interval, + * writeback on it has already started. No need to kick it + * off again. Also, don't start a new one if there's + * already one in flight. */ - if (PageAnon(page)) - SetPageCgroupMigration(pc); + if (time_after64(frn->at, now - intv) && + atomic_read(&frn->done.cnt) == 1) { + frn->at = 0; + trace_flush_foreign(wb, frn->bdi_id, frn->memcg_id); + cgroup_writeback_by_id(frn->bdi_id, frn->memcg_id, + WB_REASON_FOREIGN_FLUSH, + &frn->done); + } } - unlock_page_cgroup(pc); - /* - * If the page is not charged at this point, - * we return here. - */ - if (!memcg) - return; - - *memcgp = memcg; - /* - * We charge new page before it's used/mapped. So, even if unlock_page() - * is called before end_migration, we can catch all events on this new - * page. In the case new page is migrated but not remapped, new page's - * mapcount will be finally 0 and we call uncharge in end_migration(). - */ - if (PageAnon(page)) - ctype = MEM_CGROUP_CHARGE_TYPE_ANON; - else - ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; - /* - * The page is committed to the memcg, but it's not actually - * charged to the res_counter since we plan on replacing the - * old one and only one page is going to be left afterwards. - */ - __mem_cgroup_commit_charge(memcg, newpage, nr_pages, ctype, false); } -/* remove redundant charge if migration failed*/ -void mem_cgroup_end_migration(struct mem_cgroup *memcg, - struct page *oldpage, struct page *newpage, bool migration_ok) -{ - struct page *used, *unused; - struct page_cgroup *pc; - bool anon; +#else /* CONFIG_CGROUP_WRITEBACK */ - if (!memcg) - return; +static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp) +{ + return 0; +} - if (!migration_ok) { - used = oldpage; - unused = newpage; - } else { - used = newpage; - unused = oldpage; - } - anon = PageAnon(used); - __mem_cgroup_uncharge_common(unused, - anon ? MEM_CGROUP_CHARGE_TYPE_ANON - : MEM_CGROUP_CHARGE_TYPE_CACHE, - true); - css_put(&memcg->css); - /* - * We disallowed uncharge of pages under migration because mapcount - * of the page goes down to zero, temporarly. - * Clear the flag and check the page should be charged. - */ - pc = lookup_page_cgroup(oldpage); - lock_page_cgroup(pc); - ClearPageCgroupMigration(pc); - unlock_page_cgroup(pc); +static void memcg_wb_domain_exit(struct mem_cgroup *memcg) +{ +} - /* - * If a page is a file cache, radix-tree replacement is very atomic - * and we can skip this check. When it was an Anon page, its mapcount - * goes down to 0. But because we added MIGRATION flage, it's not - * uncharged yet. There are several case but page->mapcount check - * and USED bit check in mem_cgroup_uncharge_page() will do enough - * check. (see prepare_charge() also) - */ - if (anon) - mem_cgroup_uncharge_page(used); +static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg) +{ } +#endif /* CONFIG_CGROUP_WRITEBACK */ + /* - * At replace page cache, newpage is not under any memcg but it's on - * LRU. So, this function doesn't touch res_counter but handles LRU - * in correct way. Both pages are locked so we cannot race with uncharge. + * Private memory cgroup IDR + * + * Swap-out records and page cache shadow entries need to store memcg + * references in constrained space, so we maintain an ID space that is + * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of + * memory-controlled cgroups to 64k. + * + * However, there usually are many references to the offline CSS after + * the cgroup has been destroyed, such as page cache or reclaimable + * slab objects, that don't need to hang on to the ID. We want to keep + * those dead CSS from occupying IDs, or we might quickly exhaust the + * relatively small ID space and prevent the creation of new cgroups + * even when there are much fewer than 64k cgroups - possibly none. + * + * Maintain a private 16-bit ID space for memcg, and allow the ID to + * be freed and recycled when it's no longer needed, which is usually + * when the CSS is offlined. + * + * The only exception to that are records of swapped out tmpfs/shmem + * pages that need to be attributed to live ancestors on swapin. But + * those references are manageable from userspace. */ -void mem_cgroup_replace_page_cache(struct page *oldpage, - struct page *newpage) -{ - struct mem_cgroup *memcg = NULL; - struct page_cgroup *pc; - enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE; - if (mem_cgroup_disabled()) - return; +#define MEM_CGROUP_ID_MAX ((1UL << MEM_CGROUP_ID_SHIFT) - 1) +static DEFINE_XARRAY_ALLOC1(mem_cgroup_ids); - pc = lookup_page_cgroup(oldpage); - /* fix accounting on old pages */ - lock_page_cgroup(pc); - if (PageCgroupUsed(pc)) { - memcg = pc->mem_cgroup; - mem_cgroup_charge_statistics(memcg, oldpage, false, -1); - ClearPageCgroupUsed(pc); +static void mem_cgroup_id_remove(struct mem_cgroup *memcg) +{ + if (memcg->id.id > 0) { + xa_erase(&mem_cgroup_ids, memcg->id.id); + memcg->id.id = 0; } - unlock_page_cgroup(pc); - - /* - * When called from shmem_replace_page(), in some cases the - * oldpage has already been charged, and in some cases not. - */ - if (!memcg) - return; - /* - * Even if newpage->mapping was NULL before starting replacement, - * the newpage may be on LRU(or pagevec for LRU) already. We lock - * LRU while we overwrite pc->mem_cgroup. - */ - __mem_cgroup_commit_charge(memcg, newpage, 1, type, true); } -#ifdef CONFIG_DEBUG_VM -static struct page_cgroup *lookup_page_cgroup_used(struct page *page) +void __maybe_unused mem_cgroup_id_get_many(struct mem_cgroup *memcg, + unsigned int n) { - struct page_cgroup *pc; - - pc = lookup_page_cgroup(page); - /* - * Can be NULL while feeding pages into the page allocator for - * the first time, i.e. during boot or memory hotplug; - * or when mem_cgroup_disabled(). - */ - if (likely(pc) && PageCgroupUsed(pc)) - return pc; - return NULL; + refcount_add(n, &memcg->id.ref); } -bool mem_cgroup_bad_page_check(struct page *page) +static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n) { - if (mem_cgroup_disabled()) - return false; + if (refcount_sub_and_test(n, &memcg->id.ref)) { + mem_cgroup_id_remove(memcg); - return lookup_page_cgroup_used(page) != NULL; + /* Memcg ID pins CSS */ + css_put(&memcg->css); + } } -void mem_cgroup_print_bad_page(struct page *page) +static inline void mem_cgroup_id_put(struct mem_cgroup *memcg) { - struct page_cgroup *pc; - - pc = lookup_page_cgroup_used(page); - if (pc) { - pr_alert("pc:%p pc->flags:%lx pc->mem_cgroup:%p\n", - pc, pc->flags, pc->mem_cgroup); - } + mem_cgroup_id_put_many(memcg, 1); } -#endif -static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, - unsigned long long val) +struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg) { - int retry_count; - u64 memswlimit, memlimit; - int ret = 0; - int children = mem_cgroup_count_children(memcg); - u64 curusage, oldusage; - int enlarge; - - /* - * For keeping hierarchical_reclaim simple, how long we should retry - * is depends on callers. We set our retry-count to be function - * of # of children which we should visit in this loop. - */ - retry_count = MEM_CGROUP_RECLAIM_RETRIES * children; - - oldusage = res_counter_read_u64(&memcg->res, RES_USAGE); - - enlarge = 0; - while (retry_count) { - if (signal_pending(current)) { - ret = -EINTR; - break; - } + while (!refcount_inc_not_zero(&memcg->id.ref)) { /* - * Rather than hide all in some function, I do this in - * open coded manner. You see what this really does. - * We have to guarantee memcg->res.limit <= memcg->memsw.limit. + * The root cgroup cannot be destroyed, so it's refcount must + * always be >= 1. */ - mutex_lock(&set_limit_mutex); - memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); - if (memswlimit < val) { - ret = -EINVAL; - mutex_unlock(&set_limit_mutex); + if (WARN_ON_ONCE(mem_cgroup_is_root(memcg))) { + VM_BUG_ON(1); break; } - - memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); - if (memlimit < val) - enlarge = 1; - - ret = res_counter_set_limit(&memcg->res, val); - if (!ret) { - if (memswlimit == val) - memcg->memsw_is_minimum = true; - else - memcg->memsw_is_minimum = false; - } - mutex_unlock(&set_limit_mutex); - - if (!ret) - break; - - mem_cgroup_reclaim(memcg, GFP_KERNEL, - MEM_CGROUP_RECLAIM_SHRINK); - curusage = res_counter_read_u64(&memcg->res, RES_USAGE); - /* Usage is reduced ? */ - if (curusage >= oldusage) - retry_count--; - else - oldusage = curusage; + memcg = parent_mem_cgroup(memcg); + if (!memcg) + memcg = root_mem_cgroup; } - if (!ret && enlarge) - memcg_oom_recover(memcg); + return memcg; +} - return ret; +/** + * mem_cgroup_from_id - look up a memcg from a memcg id + * @id: the memcg id to look up + * + * Caller must hold rcu_read_lock(). + */ +struct mem_cgroup *mem_cgroup_from_id(unsigned short id) +{ + WARN_ON_ONCE(!rcu_read_lock_held()); + return xa_load(&mem_cgroup_ids, id); } -static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, - unsigned long long val) +#ifdef CONFIG_SHRINKER_DEBUG +struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino) { - int retry_count; - u64 memlimit, memswlimit, oldusage, curusage; - int children = mem_cgroup_count_children(memcg); - int ret = -EBUSY; - int enlarge = 0; + struct cgroup *cgrp; + struct cgroup_subsys_state *css; + struct mem_cgroup *memcg; - /* see mem_cgroup_resize_res_limit */ - retry_count = children * MEM_CGROUP_RECLAIM_RETRIES; - oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); - while (retry_count) { - if (signal_pending(current)) { - ret = -EINTR; - break; - } - /* - * Rather than hide all in some function, I do this in - * open coded manner. You see what this really does. - * We have to guarantee memcg->res.limit <= memcg->memsw.limit. - */ - mutex_lock(&set_limit_mutex); - memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); - if (memlimit > val) { - ret = -EINVAL; - mutex_unlock(&set_limit_mutex); - break; - } - memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); - if (memswlimit < val) - enlarge = 1; - ret = res_counter_set_limit(&memcg->memsw, val); - if (!ret) { - if (memlimit == val) - memcg->memsw_is_minimum = true; - else - memcg->memsw_is_minimum = false; - } - mutex_unlock(&set_limit_mutex); + cgrp = cgroup_get_from_id(ino); + if (IS_ERR(cgrp)) + return ERR_CAST(cgrp); - if (!ret) - break; + css = cgroup_get_e_css(cgrp, &memory_cgrp_subsys); + if (css) + memcg = container_of(css, struct mem_cgroup, css); + else + memcg = ERR_PTR(-ENOENT); - mem_cgroup_reclaim(memcg, GFP_KERNEL, - MEM_CGROUP_RECLAIM_NOSWAP | - MEM_CGROUP_RECLAIM_SHRINK); - curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); - /* Usage is reduced ? */ - if (curusage >= oldusage) - retry_count--; - else - oldusage = curusage; - } - if (!ret && enlarge) - memcg_oom_recover(memcg); - return ret; + cgroup_put(cgrp); + + return memcg; } +#endif -unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, - gfp_t gfp_mask, - unsigned long *total_scanned) +static void free_mem_cgroup_per_node_info(struct mem_cgroup_per_node *pn) { - unsigned long nr_reclaimed = 0; - struct mem_cgroup_per_zone *mz, *next_mz = NULL; - unsigned long reclaimed; - int loop = 0; - struct mem_cgroup_tree_per_zone *mctz; - unsigned long long excess; - unsigned long nr_scanned; - - if (order > 0) - return 0; - - mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone)); - /* - * This loop can run a while, specially if mem_cgroup's continuously - * keep exceeding their soft limit and putting the system under - * pressure - */ - do { - if (next_mz) - mz = next_mz; - else - mz = mem_cgroup_largest_soft_limit_node(mctz); - if (!mz) - break; - - nr_scanned = 0; - reclaimed = mem_cgroup_soft_reclaim(mz->memcg, zone, - gfp_mask, &nr_scanned); - nr_reclaimed += reclaimed; - *total_scanned += nr_scanned; - spin_lock(&mctz->lock); + if (!pn) + return; - /* - * If we failed to reclaim anything from this memory cgroup - * it is time to move on to the next cgroup - */ - next_mz = NULL; - if (!reclaimed) { - do { - /* - * Loop until we find yet another one. - * - * By the time we get the soft_limit lock - * again, someone might have aded the - * group back on the RB tree. Iterate to - * make sure we get a different mem. - * mem_cgroup_largest_soft_limit_node returns - * NULL if no other cgroup is present on - * the tree - */ - next_mz = - __mem_cgroup_largest_soft_limit_node(mctz); - if (next_mz == mz) - css_put(&next_mz->memcg->css); - else /* next_mz == NULL or other memcg */ - break; - } while (1); - } - __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz); - excess = res_counter_soft_limit_excess(&mz->memcg->res); - /* - * One school of thought says that we should not add - * back the node to the tree if reclaim returns 0. - * But our reclaim could return 0, simply because due - * to priority we are exposing a smaller subset of - * memory to reclaim from. Consider this as a longer - * term TODO. - */ - /* If excess == 0, no tree ops */ - __mem_cgroup_insert_exceeded(mz->memcg, mz, mctz, excess); - spin_unlock(&mctz->lock); - css_put(&mz->memcg->css); - loop++; - /* - * Could not reclaim anything and there are no more - * mem cgroups to try or we seem to be looping without - * reclaiming anything. - */ - if (!nr_reclaimed && - (next_mz == NULL || - loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS)) - break; - } while (!nr_reclaimed); - if (next_mz) - css_put(&next_mz->memcg->css); - return nr_reclaimed; + free_percpu(pn->lruvec_stats_percpu); + kfree(pn->lruvec_stats); + kfree(pn); } -/** - * mem_cgroup_force_empty_list - clears LRU of a group - * @memcg: group to clear - * @node: NUMA node - * @zid: zone id - * @lru: lru to to clear - * - * Traverse a specified page_cgroup list and try to drop them all. This doesn't - * reclaim the pages page themselves - pages are moved to the parent (or root) - * group. - */ -static void mem_cgroup_force_empty_list(struct mem_cgroup *memcg, - int node, int zid, enum lru_list lru) +static bool alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node) { - struct lruvec *lruvec; - unsigned long flags; - struct list_head *list; - struct page *busy; - struct zone *zone; + struct mem_cgroup_per_node *pn; - zone = &NODE_DATA(node)->node_zones[zid]; - lruvec = mem_cgroup_zone_lruvec(zone, memcg); - list = &lruvec->lists[lru]; + pn = kmem_cache_alloc_node(memcg_pn_cachep, GFP_KERNEL | __GFP_ZERO, + node); + if (!pn) + return false; - busy = NULL; - do { - struct page_cgroup *pc; - struct page *page; + pn->lruvec_stats = kzalloc_node(sizeof(struct lruvec_stats), + GFP_KERNEL_ACCOUNT, node); + if (!pn->lruvec_stats) + goto fail; - spin_lock_irqsave(&zone->lru_lock, flags); - if (list_empty(list)) { - spin_unlock_irqrestore(&zone->lru_lock, flags); - break; - } - page = list_entry(list->prev, struct page, lru); - if (busy == page) { - list_move(&page->lru, list); - busy = NULL; - spin_unlock_irqrestore(&zone->lru_lock, flags); - continue; - } - spin_unlock_irqrestore(&zone->lru_lock, flags); + pn->lruvec_stats_percpu = alloc_percpu_gfp(struct lruvec_stats_percpu, + GFP_KERNEL_ACCOUNT); + if (!pn->lruvec_stats_percpu) + goto fail; - pc = lookup_page_cgroup(page); + lruvec_init(&pn->lruvec); + pn->memcg = memcg; - if (mem_cgroup_move_parent(page, pc, memcg)) { - /* found lock contention or "pc" is obsolete. */ - busy = page; - cond_resched(); - } else - busy = NULL; - } while (!list_empty(list)); + memcg->nodeinfo[node] = pn; + return true; +fail: + free_mem_cgroup_per_node_info(pn); + return false; } -/* - * make mem_cgroup's charge to be 0 if there is no task by moving - * all the charges and pages to the parent. - * This enables deleting this mem_cgroup. - * - * Caller is responsible for holding css reference on the memcg. - */ -static void mem_cgroup_reparent_charges(struct mem_cgroup *memcg) +static void __mem_cgroup_free(struct mem_cgroup *memcg) { - int node, zid; - u64 usage; + int node; - do { - /* This is for making all *used* pages to be on LRU. */ - lru_add_drain_all(); - drain_all_stock_sync(memcg); - mem_cgroup_start_move(memcg); - for_each_node_state(node, N_MEMORY) { - for (zid = 0; zid < MAX_NR_ZONES; zid++) { - enum lru_list lru; - for_each_lru(lru) { - mem_cgroup_force_empty_list(memcg, - node, zid, lru); - } - } - } - mem_cgroup_end_move(memcg); - memcg_oom_recover(memcg); - cond_resched(); + obj_cgroup_put(memcg->orig_objcg); - /* - * Kernel memory may not necessarily be trackable to a specific - * process. So they are not migrated, and therefore we can't - * expect their value to drop to 0 here. - * Having res filled up with kmem only is enough. - * - * This is a safety check because mem_cgroup_force_empty_list - * could have raced with mem_cgroup_replace_page_cache callers - * so the lru seemed empty but the page could have been added - * right after the check. RES_USAGE should be safe as we always - * charge before adding to the LRU. - */ - usage = res_counter_read_u64(&memcg->res, RES_USAGE) - - res_counter_read_u64(&memcg->kmem, RES_USAGE); - } while (usage > 0); + for_each_node(node) + free_mem_cgroup_per_node_info(memcg->nodeinfo[node]); + memcg1_free_events(memcg); + kfree(memcg->vmstats); + free_percpu(memcg->vmstats_percpu); + kfree(memcg); } -/* - * This mainly exists for tests during the setting of set of use_hierarchy. - * Since this is the very setting we are changing, the current hierarchy value - * is meaningless - */ -static inline bool __memcg_has_children(struct mem_cgroup *memcg) +static void mem_cgroup_free(struct mem_cgroup *memcg) { - struct cgroup *pos; - - /* bounce at first found */ - cgroup_for_each_child(pos, memcg->css.cgroup) - return true; - return false; + lru_gen_exit_memcg(memcg); + memcg_wb_domain_exit(memcg); + __mem_cgroup_free(memcg); } -/* - * Must be called with memcg_create_mutex held, unless the cgroup is guaranteed - * to be already dead (as in mem_cgroup_force_empty, for instance). This is - * from mem_cgroup_count_children(), in the sense that we don't really care how - * many children we have; we only need to know if we have any. It also counts - * any memcg without hierarchy as infertile. - */ -static inline bool memcg_has_children(struct mem_cgroup *memcg) +static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent) { - return memcg->use_hierarchy && __memcg_has_children(memcg); -} + struct memcg_vmstats_percpu *statc; + struct memcg_vmstats_percpu __percpu *pstatc_pcpu; + struct mem_cgroup *memcg; + int node, cpu; + int __maybe_unused i; + long error; -/* - * Reclaims as many pages from the given memcg as possible and moves - * the rest to the parent. - * - * Caller is responsible for holding css reference for memcg. - */ -static int mem_cgroup_force_empty(struct mem_cgroup *memcg) -{ - int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; - struct cgroup *cgrp = memcg->css.cgroup; + memcg = kmem_cache_zalloc(memcg_cachep, GFP_KERNEL); + if (!memcg) + return ERR_PTR(-ENOMEM); - /* returns EBUSY if there is a task or if we come here twice. */ - if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children)) - return -EBUSY; + error = xa_alloc(&mem_cgroup_ids, &memcg->id.id, NULL, + XA_LIMIT(1, MEM_CGROUP_ID_MAX), GFP_KERNEL); + if (error) + goto fail; + error = -ENOMEM; - /* we call try-to-free pages for make this cgroup empty */ - lru_add_drain_all(); - /* try to free all pages in this cgroup */ - while (nr_retries && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) { - int progress; + memcg->vmstats = kzalloc(sizeof(struct memcg_vmstats), + GFP_KERNEL_ACCOUNT); + if (!memcg->vmstats) + goto fail; - if (signal_pending(current)) - return -EINTR; - - progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL, - false); - if (!progress) { - nr_retries--; - /* maybe some writeback is necessary */ - congestion_wait(BLK_RW_ASYNC, HZ/10); - } + memcg->vmstats_percpu = alloc_percpu_gfp(struct memcg_vmstats_percpu, + GFP_KERNEL_ACCOUNT); + if (!memcg->vmstats_percpu) + goto fail; - } - lru_add_drain(); - mem_cgroup_reparent_charges(memcg); + if (!memcg1_alloc_events(memcg)) + goto fail; - return 0; -} + for_each_possible_cpu(cpu) { + if (parent) + pstatc_pcpu = parent->vmstats_percpu; + statc = per_cpu_ptr(memcg->vmstats_percpu, cpu); + statc->parent_pcpu = parent ? pstatc_pcpu : NULL; + statc->vmstats = memcg->vmstats; + } -static int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event) -{ - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); - int ret; + for_each_node(node) + if (!alloc_mem_cgroup_per_node_info(memcg, node)) + goto fail; - if (mem_cgroup_is_root(memcg)) - return -EINVAL; - css_get(&memcg->css); - ret = mem_cgroup_force_empty(memcg); - css_put(&memcg->css); + if (memcg_wb_domain_init(memcg, GFP_KERNEL)) + goto fail; - return ret; + INIT_WORK(&memcg->high_work, high_work_func); + vmpressure_init(&memcg->vmpressure); + INIT_LIST_HEAD(&memcg->memory_peaks); + INIT_LIST_HEAD(&memcg->swap_peaks); + spin_lock_init(&memcg->peaks_lock); + memcg->socket_pressure = get_jiffies_64(); +#if BITS_PER_LONG < 64 + seqlock_init(&memcg->socket_pressure_seqlock); +#endif + memcg1_memcg_init(memcg); + memcg->kmemcg_id = -1; + INIT_LIST_HEAD(&memcg->objcg_list); +#ifdef CONFIG_CGROUP_WRITEBACK + INIT_LIST_HEAD(&memcg->cgwb_list); + for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) + memcg->cgwb_frn[i].done = + __WB_COMPLETION_INIT(&memcg_cgwb_frn_waitq); +#endif +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + spin_lock_init(&memcg->deferred_split_queue.split_queue_lock); + INIT_LIST_HEAD(&memcg->deferred_split_queue.split_queue); + memcg->deferred_split_queue.split_queue_len = 0; +#endif + lru_gen_init_memcg(memcg); + return memcg; +fail: + mem_cgroup_id_remove(memcg); + __mem_cgroup_free(memcg); + return ERR_PTR(error); } +static struct cgroup_subsys_state * __ref +mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) +{ + struct mem_cgroup *parent = mem_cgroup_from_css(parent_css); + struct mem_cgroup *memcg, *old_memcg; + bool memcg_on_dfl = cgroup_subsys_on_dfl(memory_cgrp_subsys); + + old_memcg = set_active_memcg(parent); + memcg = mem_cgroup_alloc(parent); + set_active_memcg(old_memcg); + if (IS_ERR(memcg)) + return ERR_CAST(memcg); + + page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX); + memcg1_soft_limit_reset(memcg); +#ifdef CONFIG_ZSWAP + memcg->zswap_max = PAGE_COUNTER_MAX; + WRITE_ONCE(memcg->zswap_writeback, true); +#endif + page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX); + if (parent) { + WRITE_ONCE(memcg->swappiness, mem_cgroup_swappiness(parent)); + + page_counter_init(&memcg->memory, &parent->memory, memcg_on_dfl); + page_counter_init(&memcg->swap, &parent->swap, false); +#ifdef CONFIG_MEMCG_V1 + memcg->memory.track_failcnt = !memcg_on_dfl; + WRITE_ONCE(memcg->oom_kill_disable, READ_ONCE(parent->oom_kill_disable)); + page_counter_init(&memcg->kmem, &parent->kmem, false); + page_counter_init(&memcg->tcpmem, &parent->tcpmem, false); +#endif + } else { + init_memcg_stats(); + init_memcg_events(); + page_counter_init(&memcg->memory, NULL, true); + page_counter_init(&memcg->swap, NULL, false); +#ifdef CONFIG_MEMCG_V1 + page_counter_init(&memcg->kmem, NULL, false); + page_counter_init(&memcg->tcpmem, NULL, false); +#endif + root_mem_cgroup = memcg; + return &memcg->css; + } + + if (memcg_on_dfl && !cgroup_memory_nosocket) + static_branch_inc(&memcg_sockets_enabled_key); -static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft) -{ - return mem_cgroup_from_cont(cont)->use_hierarchy; + if (!cgroup_memory_nobpf) + static_branch_inc(&memcg_bpf_enabled_key); + + return &memcg->css; } -static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft, - u64 val) +static int mem_cgroup_css_online(struct cgroup_subsys_state *css) { - int retval = 0; - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); - struct cgroup *parent = cont->parent; - struct mem_cgroup *parent_memcg = NULL; + struct mem_cgroup *memcg = mem_cgroup_from_css(css); - if (parent) - parent_memcg = mem_cgroup_from_cont(parent); + if (memcg_online_kmem(memcg)) + goto remove_id; - mutex_lock(&memcg_create_mutex); + /* + * A memcg must be visible for expand_shrinker_info() + * by the time the maps are allocated. So, we allocate maps + * here, when for_each_mem_cgroup() can't skip it. + */ + if (alloc_shrinker_info(memcg)) + goto offline_kmem; - if (memcg->use_hierarchy == val) - goto out; + if (unlikely(mem_cgroup_is_root(memcg)) && !mem_cgroup_disabled()) + queue_delayed_work(system_unbound_wq, &stats_flush_dwork, + FLUSH_TIME); + lru_gen_online_memcg(memcg); + + /* Online state pins memcg ID, memcg ID pins CSS */ + refcount_set(&memcg->id.ref, 1); + css_get(css); /* - * If parent's use_hierarchy is set, we can't make any modifications - * in the child subtrees. If it is unset, then the change can - * occur, provided the current cgroup has no children. + * Ensure mem_cgroup_from_id() works once we're fully online. * - * For the root cgroup, parent_mem is NULL, we allow value to be - * set if there are no children. + * We could do this earlier and require callers to filter with + * css_tryget_online(). But right now there are no users that + * need earlier access, and the workingset code relies on the + * cgroup tree linkage (mem_cgroup_get_nr_swap_pages()). So + * publish it here at the end of onlining. This matches the + * regular ID destruction during offlining. */ - if ((!parent_memcg || !parent_memcg->use_hierarchy) && - (val == 1 || val == 0)) { - if (!__memcg_has_children(memcg)) - memcg->use_hierarchy = val; - else - retval = -EBUSY; - } else - retval = -EINVAL; + xa_store(&mem_cgroup_ids, memcg->id.id, memcg, GFP_KERNEL); -out: - mutex_unlock(&memcg_create_mutex); - - return retval; + return 0; +offline_kmem: + memcg_offline_kmem(memcg); +remove_id: + mem_cgroup_id_remove(memcg); + return -ENOMEM; } - -static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *memcg, - enum mem_cgroup_stat_index idx) +static void mem_cgroup_css_offline(struct cgroup_subsys_state *css) { - struct mem_cgroup *iter; - long val = 0; + struct mem_cgroup *memcg = mem_cgroup_from_css(css); - /* Per-cpu values can be negative, use a signed accumulator */ - for_each_mem_cgroup_tree(iter, memcg) - val += mem_cgroup_read_stat(iter, idx); - - if (val < 0) /* race ? */ - val = 0; - return val; -} + memcg1_css_offline(memcg); -static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) -{ - u64 val; + page_counter_set_min(&memcg->memory, 0); + page_counter_set_low(&memcg->memory, 0); - if (!mem_cgroup_is_root(memcg)) { - if (!swap) - return res_counter_read_u64(&memcg->res, RES_USAGE); - else - return res_counter_read_u64(&memcg->memsw, RES_USAGE); - } + zswap_memcg_offline_cleanup(memcg); - /* - * Transparent hugepages are still accounted for in MEM_CGROUP_STAT_RSS - * as well as in MEM_CGROUP_STAT_RSS_HUGE. - */ - val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE); - val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS); + memcg_offline_kmem(memcg); + reparent_deferred_split_queue(memcg); + reparent_shrinker_deferred(memcg); + wb_memcg_offline(memcg); + lru_gen_offline_memcg(memcg); - if (swap) - val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAP); + drain_all_stock(memcg); - return val << PAGE_SHIFT; + mem_cgroup_id_put(memcg); } -static ssize_t mem_cgroup_read(struct cgroup *cont, struct cftype *cft, - struct file *file, char __user *buf, - size_t nbytes, loff_t *ppos) +static void mem_cgroup_css_released(struct cgroup_subsys_state *css) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); - char str[64]; - u64 val; - int name, len; - enum res_type type; - - type = MEMFILE_TYPE(cft->private); - name = MEMFILE_ATTR(cft->private); + struct mem_cgroup *memcg = mem_cgroup_from_css(css); - switch (type) { - case _MEM: - if (name == RES_USAGE) - val = mem_cgroup_usage(memcg, false); - else - val = res_counter_read_u64(&memcg->res, name); - break; - case _MEMSWAP: - if (name == RES_USAGE) - val = mem_cgroup_usage(memcg, true); - else - val = res_counter_read_u64(&memcg->memsw, name); - break; - case _KMEM: - val = res_counter_read_u64(&memcg->kmem, name); - break; - default: - BUG(); - } - - len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val); - return simple_read_from_buffer(buf, nbytes, ppos, str, len); + invalidate_reclaim_iterators(memcg); + lru_gen_release_memcg(memcg); } -static int memcg_update_kmem_limit(struct cgroup *cont, u64 val) +static void mem_cgroup_css_free(struct cgroup_subsys_state *css) { - int ret = -EINVAL; -#ifdef CONFIG_MEMCG_KMEM - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); - /* - * For simplicity, we won't allow this to be disabled. It also can't - * be changed if the cgroup has children already, or if tasks had - * already joined. - * - * If tasks join before we set the limit, a person looking at - * kmem.usage_in_bytes will have no way to determine when it took - * place, which makes the value quite meaningless. - * - * After it first became limited, changes in the value of the limit are - * of course permitted. - */ - mutex_lock(&memcg_create_mutex); - mutex_lock(&set_limit_mutex); - if (!memcg->kmem_account_flags && val != RESOURCE_MAX) { - if (cgroup_task_count(cont) || memcg_has_children(memcg)) { - ret = -EBUSY; - goto out; - } - ret = res_counter_set_limit(&memcg->kmem, val); - VM_BUG_ON(ret); + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + int __maybe_unused i; - ret = memcg_update_cache_sizes(memcg); - if (ret) { - res_counter_set_limit(&memcg->kmem, RESOURCE_MAX); - goto out; - } - static_key_slow_inc(&memcg_kmem_enabled_key); - /* - * setting the active bit after the inc will guarantee no one - * starts accounting before all call sites are patched - */ - memcg_kmem_set_active(memcg); - } else - ret = res_counter_set_limit(&memcg->kmem, val); -out: - mutex_unlock(&set_limit_mutex); - mutex_unlock(&memcg_create_mutex); +#ifdef CONFIG_CGROUP_WRITEBACK + for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) + wb_wait_for_completion(&memcg->cgwb_frn[i].done); #endif - return ret; -} + if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket) + static_branch_dec(&memcg_sockets_enabled_key); -#ifdef CONFIG_MEMCG_KMEM -static int memcg_propagate_kmem(struct mem_cgroup *memcg) -{ - int ret = 0; - struct mem_cgroup *parent = parent_mem_cgroup(memcg); - if (!parent) - goto out; - - memcg->kmem_account_flags = parent->kmem_account_flags; - /* - * When that happen, we need to disable the static branch only on those - * memcgs that enabled it. To achieve this, we would be forced to - * complicate the code by keeping track of which memcgs were the ones - * that actually enabled limits, and which ones got it from its - * parents. - * - * It is a lot simpler just to do static_key_slow_inc() on every child - * that is accounted. - */ - if (!memcg_kmem_is_active(memcg)) - goto out; + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg1_tcpmem_active(memcg)) + static_branch_dec(&memcg_sockets_enabled_key); - /* - * __mem_cgroup_free() will issue static_key_slow_dec() because this - * memcg is active already. If the later initialization fails then the - * cgroup core triggers the cleanup so we do not have to do it here. - */ - static_key_slow_inc(&memcg_kmem_enabled_key); + if (!cgroup_memory_nobpf) + static_branch_dec(&memcg_bpf_enabled_key); - mutex_lock(&set_limit_mutex); - memcg_stop_kmem_account(); - ret = memcg_update_cache_sizes(memcg); - memcg_resume_kmem_account(); - mutex_unlock(&set_limit_mutex); -out: - return ret; + vmpressure_cleanup(&memcg->vmpressure); + cancel_work_sync(&memcg->high_work); + memcg1_remove_from_trees(memcg); + free_shrinker_info(memcg); + mem_cgroup_free(memcg); } -#endif /* CONFIG_MEMCG_KMEM */ -/* - * The user of this function is... - * RES_LIMIT. +/** + * mem_cgroup_css_reset - reset the states of a mem_cgroup + * @css: the target css + * + * Reset the states of the mem_cgroup associated with @css. This is + * invoked when the userland requests disabling on the default hierarchy + * but the memcg is pinned through dependency. The memcg should stop + * applying policies and should revert to the vanilla state as it may be + * made visible again. + * + * The current implementation only resets the essential configurations. + * This needs to be expanded to cover all the visible parts. */ -static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft, - const char *buffer) +static void mem_cgroup_css_reset(struct cgroup_subsys_state *css) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); - enum res_type type; - int name; - unsigned long long val; - int ret; + struct mem_cgroup *memcg = mem_cgroup_from_css(css); - type = MEMFILE_TYPE(cft->private); - name = MEMFILE_ATTR(cft->private); + page_counter_set_max(&memcg->memory, PAGE_COUNTER_MAX); + page_counter_set_max(&memcg->swap, PAGE_COUNTER_MAX); +#ifdef CONFIG_MEMCG_V1 + page_counter_set_max(&memcg->kmem, PAGE_COUNTER_MAX); + page_counter_set_max(&memcg->tcpmem, PAGE_COUNTER_MAX); +#endif + page_counter_set_min(&memcg->memory, 0); + page_counter_set_low(&memcg->memory, 0); + page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX); + memcg1_soft_limit_reset(memcg); + page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX); + memcg_wb_domain_size_changed(memcg); +} + +struct aggregate_control { + /* pointer to the aggregated (CPU and subtree aggregated) counters */ + long *aggregate; + /* pointer to the non-hierarchichal (CPU aggregated) counters */ + long *local; + /* pointer to the pending child counters during tree propagation */ + long *pending; + /* pointer to the parent's pending counters, could be NULL */ + long *ppending; + /* pointer to the percpu counters to be aggregated */ + long *cstat; + /* pointer to the percpu counters of the last aggregation*/ + long *cstat_prev; + /* size of the above counters */ + int size; +}; - switch (name) { - case RES_LIMIT: - if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */ - ret = -EINVAL; - break; - } - /* This function does all necessary parse...reuse it */ - ret = res_counter_memparse_write_strategy(buffer, &val); - if (ret) - break; - if (type == _MEM) - ret = mem_cgroup_resize_limit(memcg, val); - else if (type == _MEMSWAP) - ret = mem_cgroup_resize_memsw_limit(memcg, val); - else if (type == _KMEM) - ret = memcg_update_kmem_limit(cont, val); - else - return -EINVAL; - break; - case RES_SOFT_LIMIT: - ret = res_counter_memparse_write_strategy(buffer, &val); - if (ret) - break; +static void mem_cgroup_stat_aggregate(struct aggregate_control *ac) +{ + int i; + long delta, delta_cpu, v; + + for (i = 0; i < ac->size; i++) { /* - * For memsw, soft limits are hard to implement in terms - * of semantics, for now, we support soft limits for - * control without swap + * Collect the aggregated propagation counts of groups + * below us. We're in a per-cpu loop here and this is + * a global counter, so the first cycle will get them. */ - if (type == _MEM) - ret = res_counter_set_soft_limit(&memcg->res, val); - else - ret = -EINVAL; - break; - default: - ret = -EINVAL; /* should be BUG() ? */ - break; - } - return ret; -} + delta = ac->pending[i]; + if (delta) + ac->pending[i] = 0; + + /* Add CPU changes on this level since the last flush */ + delta_cpu = 0; + v = READ_ONCE(ac->cstat[i]); + if (v != ac->cstat_prev[i]) { + delta_cpu = v - ac->cstat_prev[i]; + delta += delta_cpu; + ac->cstat_prev[i] = v; + } -static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg, - unsigned long long *mem_limit, unsigned long long *memsw_limit) -{ - struct cgroup *cgroup; - unsigned long long min_limit, min_memsw_limit, tmp; + /* Aggregate counts on this level and propagate upwards */ + if (delta_cpu) + ac->local[i] += delta_cpu; - min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT); - min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); - cgroup = memcg->css.cgroup; - if (!memcg->use_hierarchy) - goto out; - - while (cgroup->parent) { - cgroup = cgroup->parent; - memcg = mem_cgroup_from_cont(cgroup); - if (!memcg->use_hierarchy) - break; - tmp = res_counter_read_u64(&memcg->res, RES_LIMIT); - min_limit = min(min_limit, tmp); - tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT); - min_memsw_limit = min(min_memsw_limit, tmp); + if (delta) { + ac->aggregate[i] += delta; + if (ac->ppending) + ac->ppending[i] += delta; + } } -out: - *mem_limit = min_limit; - *memsw_limit = min_memsw_limit; } -static int mem_cgroup_reset(struct cgroup *cont, unsigned int event) +#ifdef CONFIG_MEMCG_NMI_SAFETY_REQUIRES_ATOMIC +static void flush_nmi_stats(struct mem_cgroup *memcg, struct mem_cgroup *parent, + int cpu) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); - int name; - enum res_type type; + int nid; - type = MEMFILE_TYPE(event); - name = MEMFILE_ATTR(event); + if (atomic_read(&memcg->kmem_stat)) { + int kmem = atomic_xchg(&memcg->kmem_stat, 0); + int index = memcg_stats_index(MEMCG_KMEM); - switch (name) { - case RES_MAX_USAGE: - if (type == _MEM) - res_counter_reset_max(&memcg->res); - else if (type == _MEMSWAP) - res_counter_reset_max(&memcg->memsw); - else if (type == _KMEM) - res_counter_reset_max(&memcg->kmem); - else - return -EINVAL; - break; - case RES_FAILCNT: - if (type == _MEM) - res_counter_reset_failcnt(&memcg->res); - else if (type == _MEMSWAP) - res_counter_reset_failcnt(&memcg->memsw); - else if (type == _KMEM) - res_counter_reset_failcnt(&memcg->kmem); - else - return -EINVAL; - break; + memcg->vmstats->state[index] += kmem; + if (parent) + parent->vmstats->state_pending[index] += kmem; } - return 0; -} + for_each_node_state(nid, N_MEMORY) { + struct mem_cgroup_per_node *pn = memcg->nodeinfo[nid]; + struct lruvec_stats *lstats = pn->lruvec_stats; + struct lruvec_stats *plstats = NULL; -static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp, - struct cftype *cft) -{ - return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate; -} + if (parent) + plstats = parent->nodeinfo[nid]->lruvec_stats; -#ifdef CONFIG_MMU -static int mem_cgroup_move_charge_write(struct cgroup *cgrp, - struct cftype *cft, u64 val) -{ - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + if (atomic_read(&pn->slab_reclaimable)) { + int slab = atomic_xchg(&pn->slab_reclaimable, 0); + int index = memcg_stats_index(NR_SLAB_RECLAIMABLE_B); - if (val >= (1 << NR_MOVE_TYPE)) - return -EINVAL; + lstats->state[index] += slab; + if (plstats) + plstats->state_pending[index] += slab; + } + if (atomic_read(&pn->slab_unreclaimable)) { + int slab = atomic_xchg(&pn->slab_unreclaimable, 0); + int index = memcg_stats_index(NR_SLAB_UNRECLAIMABLE_B); - /* - * No kind of locking is needed in here, because ->can_attach() will - * check this value once in the beginning of the process, and then carry - * on with stale data. This means that changes to this value will only - * affect task migrations starting after the change. - */ - memcg->move_charge_at_immigrate = val; - return 0; + lstats->state[index] += slab; + if (plstats) + plstats->state_pending[index] += slab; + } + } } #else -static int mem_cgroup_move_charge_write(struct cgroup *cgrp, - struct cftype *cft, u64 val) -{ - return -ENOSYS; -} +static void flush_nmi_stats(struct mem_cgroup *memcg, struct mem_cgroup *parent, + int cpu) +{} #endif -#ifdef CONFIG_NUMA -static int memcg_numa_stat_show(struct cgroup *cont, struct cftype *cft, - struct seq_file *m) +static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu) { + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + struct mem_cgroup *parent = parent_mem_cgroup(memcg); + struct memcg_vmstats_percpu *statc; + struct aggregate_control ac; int nid; - unsigned long total_nr, file_nr, anon_nr, unevictable_nr; - unsigned long node_nr; - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); - total_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL); - seq_printf(m, "total=%lu", total_nr); - for_each_node_state(nid, N_MEMORY) { - node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL); - seq_printf(m, " N%d=%lu", nid, node_nr); - } - seq_putc(m, '\n'); + flush_nmi_stats(memcg, parent, cpu); - file_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL_FILE); - seq_printf(m, "file=%lu", file_nr); - for_each_node_state(nid, N_MEMORY) { - node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, - LRU_ALL_FILE); - seq_printf(m, " N%d=%lu", nid, node_nr); - } - seq_putc(m, '\n'); + statc = per_cpu_ptr(memcg->vmstats_percpu, cpu); - anon_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL_ANON); - seq_printf(m, "anon=%lu", anon_nr); - for_each_node_state(nid, N_MEMORY) { - node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, - LRU_ALL_ANON); - seq_printf(m, " N%d=%lu", nid, node_nr); - } - seq_putc(m, '\n'); + ac = (struct aggregate_control) { + .aggregate = memcg->vmstats->state, + .local = memcg->vmstats->state_local, + .pending = memcg->vmstats->state_pending, + .ppending = parent ? parent->vmstats->state_pending : NULL, + .cstat = statc->state, + .cstat_prev = statc->state_prev, + .size = MEMCG_VMSTAT_SIZE, + }; + mem_cgroup_stat_aggregate(&ac); + + ac = (struct aggregate_control) { + .aggregate = memcg->vmstats->events, + .local = memcg->vmstats->events_local, + .pending = memcg->vmstats->events_pending, + .ppending = parent ? parent->vmstats->events_pending : NULL, + .cstat = statc->events, + .cstat_prev = statc->events_prev, + .size = NR_MEMCG_EVENTS, + }; + mem_cgroup_stat_aggregate(&ac); - unevictable_nr = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_UNEVICTABLE)); - seq_printf(m, "unevictable=%lu", unevictable_nr); for_each_node_state(nid, N_MEMORY) { - node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, - BIT(LRU_UNEVICTABLE)); - seq_printf(m, " N%d=%lu", nid, node_nr); + struct mem_cgroup_per_node *pn = memcg->nodeinfo[nid]; + struct lruvec_stats *lstats = pn->lruvec_stats; + struct lruvec_stats *plstats = NULL; + struct lruvec_stats_percpu *lstatc; + + if (parent) + plstats = parent->nodeinfo[nid]->lruvec_stats; + + lstatc = per_cpu_ptr(pn->lruvec_stats_percpu, cpu); + + ac = (struct aggregate_control) { + .aggregate = lstats->state, + .local = lstats->state_local, + .pending = lstats->state_pending, + .ppending = plstats ? plstats->state_pending : NULL, + .cstat = lstatc->state, + .cstat_prev = lstatc->state_prev, + .size = NR_MEMCG_NODE_STAT_ITEMS, + }; + mem_cgroup_stat_aggregate(&ac); + } - seq_putc(m, '\n'); - return 0; + WRITE_ONCE(statc->stats_updates, 0); + /* We are in a per-cpu loop here, only do the atomic write once */ + if (atomic_read(&memcg->vmstats->stats_updates)) + atomic_set(&memcg->vmstats->stats_updates, 0); } -#endif /* CONFIG_NUMA */ -static inline void mem_cgroup_lru_names_not_uptodate(void) +static void mem_cgroup_fork(struct task_struct *task) { - BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS); + /* + * Set the update flag to cause task->objcg to be initialized lazily + * on the first allocation. It can be done without any synchronization + * because it's always performed on the current task, so does + * current_objcg_update(). + */ + task->objcg = (struct obj_cgroup *)CURRENT_OBJCG_UPDATE_FLAG; } -static int memcg_stat_show(struct cgroup *cont, struct cftype *cft, - struct seq_file *m) +static void mem_cgroup_exit(struct task_struct *task) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); - struct mem_cgroup *mi; - unsigned int i; + struct obj_cgroup *objcg = task->objcg; - for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { - if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account) - continue; - seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i], - mem_cgroup_read_stat(memcg, i) * PAGE_SIZE); - } + objcg = (struct obj_cgroup *) + ((unsigned long)objcg & ~CURRENT_OBJCG_UPDATE_FLAG); + obj_cgroup_put(objcg); - for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) - seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i], - mem_cgroup_read_events(memcg, i)); + /* + * Some kernel allocations can happen after this point, + * but let's ignore them. It can be done without any synchronization + * because it's always performed on the current task, so does + * current_objcg_update(). + */ + task->objcg = NULL; +} - for (i = 0; i < NR_LRU_LISTS; i++) - seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i], - mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE); +#ifdef CONFIG_LRU_GEN +static void mem_cgroup_lru_gen_attach(struct cgroup_taskset *tset) +{ + struct task_struct *task; + struct cgroup_subsys_state *css; - /* Hierarchical information */ - { - unsigned long long limit, memsw_limit; - memcg_get_hierarchical_limit(memcg, &limit, &memsw_limit); - seq_printf(m, "hierarchical_memory_limit %llu\n", limit); - if (do_swap_account) - seq_printf(m, "hierarchical_memsw_limit %llu\n", - memsw_limit); - } + /* find the first leader if there is any */ + cgroup_taskset_for_each_leader(task, css, tset) + break; - for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { - long long val = 0; + if (!task) + return; - if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account) - continue; - for_each_mem_cgroup_tree(mi, memcg) - val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE; - seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val); - } + task_lock(task); + if (task->mm && READ_ONCE(task->mm->owner) == task) + lru_gen_migrate_mm(task->mm); + task_unlock(task); +} +#else +static void mem_cgroup_lru_gen_attach(struct cgroup_taskset *tset) {} +#endif /* CONFIG_LRU_GEN */ - for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) { - unsigned long long val = 0; +static void mem_cgroup_kmem_attach(struct cgroup_taskset *tset) +{ + struct task_struct *task; + struct cgroup_subsys_state *css; - for_each_mem_cgroup_tree(mi, memcg) - val += mem_cgroup_read_events(mi, i); - seq_printf(m, "total_%s %llu\n", - mem_cgroup_events_names[i], val); + cgroup_taskset_for_each(task, css, tset) { + /* atomically set the update bit */ + set_bit(CURRENT_OBJCG_UPDATE_BIT, (unsigned long *)&task->objcg); } +} - for (i = 0; i < NR_LRU_LISTS; i++) { - unsigned long long val = 0; - - for_each_mem_cgroup_tree(mi, memcg) - val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE; - seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val); - } +static void mem_cgroup_attach(struct cgroup_taskset *tset) +{ + mem_cgroup_lru_gen_attach(tset); + mem_cgroup_kmem_attach(tset); +} -#ifdef CONFIG_DEBUG_VM - { - int nid, zid; - struct mem_cgroup_per_zone *mz; - struct zone_reclaim_stat *rstat; - unsigned long recent_rotated[2] = {0, 0}; - unsigned long recent_scanned[2] = {0, 0}; - - for_each_online_node(nid) - for (zid = 0; zid < MAX_NR_ZONES; zid++) { - mz = mem_cgroup_zoneinfo(memcg, nid, zid); - rstat = &mz->lruvec.reclaim_stat; - - recent_rotated[0] += rstat->recent_rotated[0]; - recent_rotated[1] += rstat->recent_rotated[1]; - recent_scanned[0] += rstat->recent_scanned[0]; - recent_scanned[1] += rstat->recent_scanned[1]; - } - seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]); - seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]); - seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]); - seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]); - } -#endif +static int seq_puts_memcg_tunable(struct seq_file *m, unsigned long value) +{ + if (value == PAGE_COUNTER_MAX) + seq_puts(m, "max\n"); + else + seq_printf(m, "%llu\n", (u64)value * PAGE_SIZE); return 0; } -static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft) +static u64 memory_current_read(struct cgroup_subsys_state *css, + struct cftype *cft) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + struct mem_cgroup *memcg = mem_cgroup_from_css(css); - return mem_cgroup_swappiness(memcg); + return (u64)page_counter_read(&memcg->memory) * PAGE_SIZE; } -static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft, - u64 val) -{ - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); - struct mem_cgroup *parent; +#define OFP_PEAK_UNSET (((-1UL))) - if (val > 100) - return -EINVAL; - - if (cgrp->parent == NULL) - return -EINVAL; +static int peak_show(struct seq_file *sf, void *v, struct page_counter *pc) +{ + struct cgroup_of_peak *ofp = of_peak(sf->private); + u64 fd_peak = READ_ONCE(ofp->value), peak; - parent = mem_cgroup_from_cont(cgrp->parent); + /* User wants global or local peak? */ + if (fd_peak == OFP_PEAK_UNSET) + peak = pc->watermark; + else + peak = max(fd_peak, READ_ONCE(pc->local_watermark)); - mutex_lock(&memcg_create_mutex); + seq_printf(sf, "%llu\n", peak * PAGE_SIZE); + return 0; +} - /* If under hierarchy, only empty-root can set this value */ - if ((parent->use_hierarchy) || memcg_has_children(memcg)) { - mutex_unlock(&memcg_create_mutex); - return -EINVAL; - } +static int memory_peak_show(struct seq_file *sf, void *v) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(sf)); - memcg->swappiness = val; + return peak_show(sf, v, &memcg->memory); +} - mutex_unlock(&memcg_create_mutex); +static int peak_open(struct kernfs_open_file *of) +{ + struct cgroup_of_peak *ofp = of_peak(of); + ofp->value = OFP_PEAK_UNSET; return 0; } -static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap) +static void peak_release(struct kernfs_open_file *of) { - struct mem_cgroup_threshold_ary *t; - u64 usage; - int i; + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + struct cgroup_of_peak *ofp = of_peak(of); - rcu_read_lock(); - if (!swap) - t = rcu_dereference(memcg->thresholds.primary); - else - t = rcu_dereference(memcg->memsw_thresholds.primary); + if (ofp->value == OFP_PEAK_UNSET) { + /* fast path (no writes on this fd) */ + return; + } + spin_lock(&memcg->peaks_lock); + list_del(&ofp->list); + spin_unlock(&memcg->peaks_lock); +} - if (!t) - goto unlock; +static ssize_t peak_write(struct kernfs_open_file *of, char *buf, size_t nbytes, + loff_t off, struct page_counter *pc, + struct list_head *watchers) +{ + unsigned long usage; + struct cgroup_of_peak *peer_ctx; + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + struct cgroup_of_peak *ofp = of_peak(of); - usage = mem_cgroup_usage(memcg, swap); + spin_lock(&memcg->peaks_lock); - /* - * current_threshold points to threshold just below or equal to usage. - * If it's not true, a threshold was crossed after last - * call of __mem_cgroup_threshold(). - */ - i = t->current_threshold; + usage = page_counter_read(pc); + WRITE_ONCE(pc->local_watermark, usage); - /* - * Iterate backward over array of thresholds starting from - * current_threshold and check if a threshold is crossed. - * If none of thresholds below usage is crossed, we read - * only one element of the array here. - */ - for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--) - eventfd_signal(t->entries[i].eventfd, 1); + list_for_each_entry(peer_ctx, watchers, list) + if (usage > peer_ctx->value) + WRITE_ONCE(peer_ctx->value, usage); - /* i = current_threshold + 1 */ - i++; + /* initial write, register watcher */ + if (ofp->value == OFP_PEAK_UNSET) + list_add(&ofp->list, watchers); - /* - * Iterate forward over array of thresholds starting from - * current_threshold+1 and check if a threshold is crossed. - * If none of thresholds above usage is crossed, we read - * only one element of the array here. - */ - for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++) - eventfd_signal(t->entries[i].eventfd, 1); + WRITE_ONCE(ofp->value, usage); + spin_unlock(&memcg->peaks_lock); - /* Update current_threshold */ - t->current_threshold = i - 1; -unlock: - rcu_read_unlock(); + return nbytes; } -static void mem_cgroup_threshold(struct mem_cgroup *memcg) +static ssize_t memory_peak_write(struct kernfs_open_file *of, char *buf, + size_t nbytes, loff_t off) { - while (memcg) { - __mem_cgroup_threshold(memcg, false); - if (do_swap_account) - __mem_cgroup_threshold(memcg, true); + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); - memcg = parent_mem_cgroup(memcg); - } + return peak_write(of, buf, nbytes, off, &memcg->memory, + &memcg->memory_peaks); } -static int compare_thresholds(const void *a, const void *b) -{ - const struct mem_cgroup_threshold *_a = a; - const struct mem_cgroup_threshold *_b = b; +#undef OFP_PEAK_UNSET - return _a->threshold - _b->threshold; +static int memory_min_show(struct seq_file *m, void *v) +{ + return seq_puts_memcg_tunable(m, + READ_ONCE(mem_cgroup_from_seq(m)->memory.min)); } -static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg) +static ssize_t memory_min_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) { - struct mem_cgroup_eventfd_list *ev; + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + unsigned long min; + int err; - list_for_each_entry(ev, &memcg->oom_notify, list) - eventfd_signal(ev->eventfd, 1); - return 0; -} + buf = strstrip(buf); + err = page_counter_memparse(buf, "max", &min); + if (err) + return err; -static void mem_cgroup_oom_notify(struct mem_cgroup *memcg) -{ - struct mem_cgroup *iter; + page_counter_set_min(&memcg->memory, min); - for_each_mem_cgroup_tree(iter, memcg) - mem_cgroup_oom_notify_cb(iter); + return nbytes; } -static int mem_cgroup_usage_register_event(struct cgroup *cgrp, - struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) +static int memory_low_show(struct seq_file *m, void *v) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); - struct mem_cgroup_thresholds *thresholds; - struct mem_cgroup_threshold_ary *new; - enum res_type type = MEMFILE_TYPE(cft->private); - u64 threshold, usage; - int i, size, ret; + return seq_puts_memcg_tunable(m, + READ_ONCE(mem_cgroup_from_seq(m)->memory.low)); +} - ret = res_counter_memparse_write_strategy(args, &threshold); - if (ret) - return ret; +static ssize_t memory_low_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + unsigned long low; + int err; - mutex_lock(&memcg->thresholds_lock); + buf = strstrip(buf); + err = page_counter_memparse(buf, "max", &low); + if (err) + return err; - if (type == _MEM) - thresholds = &memcg->thresholds; - else if (type == _MEMSWAP) - thresholds = &memcg->memsw_thresholds; - else - BUG(); + page_counter_set_low(&memcg->memory, low); - usage = mem_cgroup_usage(memcg, type == _MEMSWAP); + return nbytes; +} - /* Check if a threshold crossed before adding a new one */ - if (thresholds->primary) - __mem_cgroup_threshold(memcg, type == _MEMSWAP); +static int memory_high_show(struct seq_file *m, void *v) +{ + return seq_puts_memcg_tunable(m, + READ_ONCE(mem_cgroup_from_seq(m)->memory.high)); +} - size = thresholds->primary ? thresholds->primary->size + 1 : 1; +static ssize_t memory_high_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + unsigned int nr_retries = MAX_RECLAIM_RETRIES; + bool drained = false; + unsigned long high; + int err; - /* Allocate memory for new array of thresholds */ - new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold), - GFP_KERNEL); - if (!new) { - ret = -ENOMEM; - goto unlock; - } - new->size = size; + buf = strstrip(buf); + err = page_counter_memparse(buf, "max", &high); + if (err) + return err; - /* Copy thresholds (if any) to new array */ - if (thresholds->primary) { - memcpy(new->entries, thresholds->primary->entries, (size - 1) * - sizeof(struct mem_cgroup_threshold)); - } + page_counter_set_high(&memcg->memory, high); - /* Add new threshold */ - new->entries[size - 1].eventfd = eventfd; - new->entries[size - 1].threshold = threshold; + if (of->file->f_flags & O_NONBLOCK) + goto out; - /* Sort thresholds. Registering of new threshold isn't time-critical */ - sort(new->entries, size, sizeof(struct mem_cgroup_threshold), - compare_thresholds, NULL); + for (;;) { + unsigned long nr_pages = page_counter_read(&memcg->memory); + unsigned long reclaimed; - /* Find current threshold */ - new->current_threshold = -1; - for (i = 0; i < size; i++) { - if (new->entries[i].threshold <= usage) { - /* - * new->current_threshold will not be used until - * rcu_assign_pointer(), so it's safe to increment - * it here. - */ - ++new->current_threshold; - } else + if (nr_pages <= high) break; - } - /* Free old spare buffer and save old primary buffer as spare */ - kfree(thresholds->spare); - thresholds->spare = thresholds->primary; - - rcu_assign_pointer(thresholds->primary, new); + if (signal_pending(current)) + break; - /* To be sure that nobody uses thresholds */ - synchronize_rcu(); + if (!drained) { + drain_all_stock(memcg); + drained = true; + continue; + } -unlock: - mutex_unlock(&memcg->thresholds_lock); + reclaimed = try_to_free_mem_cgroup_pages(memcg, nr_pages - high, + GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP, NULL); - return ret; + if (!reclaimed && !nr_retries--) + break; + } +out: + memcg_wb_domain_size_changed(memcg); + return nbytes; } -static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp, - struct cftype *cft, struct eventfd_ctx *eventfd) +static int memory_max_show(struct seq_file *m, void *v) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); - struct mem_cgroup_thresholds *thresholds; - struct mem_cgroup_threshold_ary *new; - enum res_type type = MEMFILE_TYPE(cft->private); - u64 usage; - int i, j, size; - - mutex_lock(&memcg->thresholds_lock); - if (type == _MEM) - thresholds = &memcg->thresholds; - else if (type == _MEMSWAP) - thresholds = &memcg->memsw_thresholds; - else - BUG(); + return seq_puts_memcg_tunable(m, + READ_ONCE(mem_cgroup_from_seq(m)->memory.max)); +} - if (!thresholds->primary) - goto unlock; +static ssize_t memory_max_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + unsigned int nr_reclaims = MAX_RECLAIM_RETRIES; + bool drained = false; + unsigned long max; + int err; - usage = mem_cgroup_usage(memcg, type == _MEMSWAP); + buf = strstrip(buf); + err = page_counter_memparse(buf, "max", &max); + if (err) + return err; - /* Check if a threshold crossed before removing */ - __mem_cgroup_threshold(memcg, type == _MEMSWAP); + xchg(&memcg->memory.max, max); - /* Calculate new number of threshold */ - size = 0; - for (i = 0; i < thresholds->primary->size; i++) { - if (thresholds->primary->entries[i].eventfd != eventfd) - size++; - } + if (of->file->f_flags & O_NONBLOCK) + goto out; - new = thresholds->spare; + for (;;) { + unsigned long nr_pages = page_counter_read(&memcg->memory); - /* Set thresholds array to NULL if we don't have thresholds */ - if (!size) { - kfree(new); - new = NULL; - goto swap_buffers; - } + if (nr_pages <= max) + break; - new->size = size; + if (signal_pending(current)) + break; - /* Copy thresholds and find current threshold */ - new->current_threshold = -1; - for (i = 0, j = 0; i < thresholds->primary->size; i++) { - if (thresholds->primary->entries[i].eventfd == eventfd) + if (!drained) { + drain_all_stock(memcg); + drained = true; continue; + } - new->entries[j] = thresholds->primary->entries[i]; - if (new->entries[j].threshold <= usage) { - /* - * new->current_threshold will not be used - * until rcu_assign_pointer(), so it's safe to increment - * it here. - */ - ++new->current_threshold; + if (nr_reclaims) { + if (!try_to_free_mem_cgroup_pages(memcg, nr_pages - max, + GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP, NULL)) + nr_reclaims--; + continue; } - j++; - } -swap_buffers: - /* Swap primary and spare array */ - thresholds->spare = thresholds->primary; - /* If all events are unregistered, free the spare array */ - if (!new) { - kfree(thresholds->spare); - thresholds->spare = NULL; + memcg_memory_event(memcg, MEMCG_OOM); + if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0)) + break; + cond_resched(); } +out: + memcg_wb_domain_size_changed(memcg); + return nbytes; +} - rcu_assign_pointer(thresholds->primary, new); - - /* To be sure that nobody uses thresholds */ - synchronize_rcu(); -unlock: - mutex_unlock(&memcg->thresholds_lock); +/* + * Note: don't forget to update the 'samples/cgroup/memcg_event_listener' + * if any new events become available. + */ +static void __memory_events_show(struct seq_file *m, atomic_long_t *events) +{ + seq_printf(m, "low %lu\n", atomic_long_read(&events[MEMCG_LOW])); + seq_printf(m, "high %lu\n", atomic_long_read(&events[MEMCG_HIGH])); + seq_printf(m, "max %lu\n", atomic_long_read(&events[MEMCG_MAX])); + seq_printf(m, "oom %lu\n", atomic_long_read(&events[MEMCG_OOM])); + seq_printf(m, "oom_kill %lu\n", + atomic_long_read(&events[MEMCG_OOM_KILL])); + seq_printf(m, "oom_group_kill %lu\n", + atomic_long_read(&events[MEMCG_OOM_GROUP_KILL])); + seq_printf(m, "sock_throttled %lu\n", + atomic_long_read(&events[MEMCG_SOCK_THROTTLED])); } -static int mem_cgroup_oom_register_event(struct cgroup *cgrp, - struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) +static int memory_events_show(struct seq_file *m, void *v) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); - struct mem_cgroup_eventfd_list *event; - enum res_type type = MEMFILE_TYPE(cft->private); + struct mem_cgroup *memcg = mem_cgroup_from_seq(m); - BUG_ON(type != _OOM_TYPE); - event = kmalloc(sizeof(*event), GFP_KERNEL); - if (!event) - return -ENOMEM; + __memory_events_show(m, memcg->memory_events); + return 0; +} - spin_lock(&memcg_oom_lock); +static int memory_events_local_show(struct seq_file *m, void *v) +{ + struct mem_cgroup *memcg = mem_cgroup_from_seq(m); - event->eventfd = eventfd; - list_add(&event->list, &memcg->oom_notify); + __memory_events_show(m, memcg->memory_events_local); + return 0; +} - /* already in OOM ? */ - if (atomic_read(&memcg->under_oom)) - eventfd_signal(eventfd, 1); - spin_unlock(&memcg_oom_lock); +int memory_stat_show(struct seq_file *m, void *v) +{ + struct mem_cgroup *memcg = mem_cgroup_from_seq(m); + char *buf = kmalloc(SEQ_BUF_SIZE, GFP_KERNEL); + struct seq_buf s; + if (!buf) + return -ENOMEM; + seq_buf_init(&s, buf, SEQ_BUF_SIZE); + memory_stat_format(memcg, &s); + seq_puts(m, buf); + kfree(buf); return 0; } -static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp, - struct cftype *cft, struct eventfd_ctx *eventfd) +#ifdef CONFIG_NUMA +static inline unsigned long lruvec_page_state_output(struct lruvec *lruvec, + int item) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); - struct mem_cgroup_eventfd_list *ev, *tmp; - enum res_type type = MEMFILE_TYPE(cft->private); + return lruvec_page_state(lruvec, item) * + memcg_page_state_output_unit(item); +} + +static int memory_numa_stat_show(struct seq_file *m, void *v) +{ + int i; + struct mem_cgroup *memcg = mem_cgroup_from_seq(m); + + mem_cgroup_flush_stats(memcg); - BUG_ON(type != _OOM_TYPE); + for (i = 0; i < ARRAY_SIZE(memory_stats); i++) { + int nid; - spin_lock(&memcg_oom_lock); + if (memory_stats[i].idx >= NR_VM_NODE_STAT_ITEMS) + continue; + + seq_printf(m, "%s", memory_stats[i].name); + for_each_node_state(nid, N_MEMORY) { + u64 size; + struct lruvec *lruvec; - list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) { - if (ev->eventfd == eventfd) { - list_del(&ev->list); - kfree(ev); + lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid)); + size = lruvec_page_state_output(lruvec, + memory_stats[i].idx); + seq_printf(m, " N%d=%llu", nid, size); } + seq_putc(m, '\n'); } - spin_unlock(&memcg_oom_lock); + return 0; } +#endif -static int mem_cgroup_oom_control_read(struct cgroup *cgrp, - struct cftype *cft, struct cgroup_map_cb *cb) +static int memory_oom_group_show(struct seq_file *m, void *v) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + struct mem_cgroup *memcg = mem_cgroup_from_seq(m); - cb->fill(cb, "oom_kill_disable", memcg->oom_kill_disable); + seq_printf(m, "%d\n", READ_ONCE(memcg->oom_group)); - if (atomic_read(&memcg->under_oom)) - cb->fill(cb, "under_oom", 1); - else - cb->fill(cb, "under_oom", 0); return 0; } -static int mem_cgroup_oom_control_write(struct cgroup *cgrp, - struct cftype *cft, u64 val) +static ssize_t memory_oom_group_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); - struct mem_cgroup *parent; + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + int ret, oom_group; - /* cannot set to root cgroup and only 0 and 1 are allowed */ - if (!cgrp->parent || !((val == 0) || (val == 1))) + buf = strstrip(buf); + if (!buf) return -EINVAL; - parent = mem_cgroup_from_cont(cgrp->parent); + ret = kstrtoint(buf, 0, &oom_group); + if (ret) + return ret; - mutex_lock(&memcg_create_mutex); - /* oom-kill-disable is a flag for subhierarchy. */ - if ((parent->use_hierarchy) || memcg_has_children(memcg)) { - mutex_unlock(&memcg_create_mutex); + if (oom_group != 0 && oom_group != 1) return -EINVAL; - } - memcg->oom_kill_disable = val; - if (!val) - memcg_oom_recover(memcg); - mutex_unlock(&memcg_create_mutex); - return 0; + + WRITE_ONCE(memcg->oom_group, oom_group); + + return nbytes; } -#ifdef CONFIG_MEMCG_KMEM -static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss) +static ssize_t memory_reclaim(struct kernfs_open_file *of, char *buf, + size_t nbytes, loff_t off) { + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); int ret; - memcg->kmemcg_id = -1; - ret = memcg_propagate_kmem(memcg); + ret = user_proactive_reclaim(buf, memcg, NULL); if (ret) return ret; - return mem_cgroup_sockets_init(memcg, ss); + return nbytes; } -static void memcg_destroy_kmem(struct mem_cgroup *memcg) -{ - mem_cgroup_sockets_destroy(memcg); -} - -static void kmem_cgroup_css_offline(struct mem_cgroup *memcg) -{ - if (!memcg_kmem_is_active(memcg)) - return; - - /* - * kmem charges can outlive the cgroup. In the case of slab - * pages, for instance, a page contain objects from various - * processes. As we prevent from taking a reference for every - * such allocation we have to be careful when doing uncharge - * (see memcg_uncharge_kmem) and here during offlining. - * - * The idea is that that only the _last_ uncharge which sees - * the dead memcg will drop the last reference. An additional - * reference is taken here before the group is marked dead - * which is then paired with css_put during uncharge resp. here. - * - * Although this might sound strange as this path is called from - * css_offline() when the referencemight have dropped down to 0 - * and shouldn't be incremented anymore (css_tryget would fail) - * we do not have other options because of the kmem allocations - * lifetime. - */ - css_get(&memcg->css); - - memcg_kmem_mark_dead(memcg); - - if (res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0) - return; - - if (memcg_kmem_test_and_clear_dead(memcg)) - css_put(&memcg->css); -} -#else -static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss) -{ - return 0; -} - -static void memcg_destroy_kmem(struct mem_cgroup *memcg) -{ -} - -static void kmem_cgroup_css_offline(struct mem_cgroup *memcg) -{ -} -#endif - -static struct cftype mem_cgroup_files[] = { - { - .name = "usage_in_bytes", - .private = MEMFILE_PRIVATE(_MEM, RES_USAGE), - .read = mem_cgroup_read, - .register_event = mem_cgroup_usage_register_event, - .unregister_event = mem_cgroup_usage_unregister_event, - }, - { - .name = "max_usage_in_bytes", - .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE), - .trigger = mem_cgroup_reset, - .read = mem_cgroup_read, - }, +static struct cftype memory_files[] = { { - .name = "limit_in_bytes", - .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT), - .write_string = mem_cgroup_write, - .read = mem_cgroup_read, + .name = "current", + .flags = CFTYPE_NOT_ON_ROOT, + .read_u64 = memory_current_read, }, { - .name = "soft_limit_in_bytes", - .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT), - .write_string = mem_cgroup_write, - .read = mem_cgroup_read, + .name = "peak", + .flags = CFTYPE_NOT_ON_ROOT, + .open = peak_open, + .release = peak_release, + .seq_show = memory_peak_show, + .write = memory_peak_write, }, { - .name = "failcnt", - .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT), - .trigger = mem_cgroup_reset, - .read = mem_cgroup_read, + .name = "min", + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = memory_min_show, + .write = memory_min_write, }, { - .name = "stat", - .read_seq_string = memcg_stat_show, - }, - { - .name = "force_empty", - .trigger = mem_cgroup_force_empty_write, + .name = "low", + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = memory_low_show, + .write = memory_low_write, }, { - .name = "use_hierarchy", - .flags = CFTYPE_INSANE, - .write_u64 = mem_cgroup_hierarchy_write, - .read_u64 = mem_cgroup_hierarchy_read, + .name = "high", + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = memory_high_show, + .write = memory_high_write, }, { - .name = "swappiness", - .read_u64 = mem_cgroup_swappiness_read, - .write_u64 = mem_cgroup_swappiness_write, + .name = "max", + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = memory_max_show, + .write = memory_max_write, }, { - .name = "move_charge_at_immigrate", - .read_u64 = mem_cgroup_move_charge_read, - .write_u64 = mem_cgroup_move_charge_write, + .name = "events", + .flags = CFTYPE_NOT_ON_ROOT, + .file_offset = offsetof(struct mem_cgroup, events_file), + .seq_show = memory_events_show, }, { - .name = "oom_control", - .read_map = mem_cgroup_oom_control_read, - .write_u64 = mem_cgroup_oom_control_write, - .register_event = mem_cgroup_oom_register_event, - .unregister_event = mem_cgroup_oom_unregister_event, - .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL), + .name = "events.local", + .flags = CFTYPE_NOT_ON_ROOT, + .file_offset = offsetof(struct mem_cgroup, events_local_file), + .seq_show = memory_events_local_show, }, { - .name = "pressure_level", - .register_event = vmpressure_register_event, - .unregister_event = vmpressure_unregister_event, + .name = "stat", + .seq_show = memory_stat_show, }, #ifdef CONFIG_NUMA { .name = "numa_stat", - .read_seq_string = memcg_numa_stat_show, + .seq_show = memory_numa_stat_show, }, #endif -#ifdef CONFIG_MEMCG_KMEM - { - .name = "kmem.limit_in_bytes", - .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT), - .write_string = mem_cgroup_write, - .read = mem_cgroup_read, - }, { - .name = "kmem.usage_in_bytes", - .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE), - .read = mem_cgroup_read, + .name = "oom.group", + .flags = CFTYPE_NOT_ON_ROOT | CFTYPE_NS_DELEGATABLE, + .seq_show = memory_oom_group_show, + .write = memory_oom_group_write, }, { - .name = "kmem.failcnt", - .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT), - .trigger = mem_cgroup_reset, - .read = mem_cgroup_read, + .name = "reclaim", + .flags = CFTYPE_NS_DELEGATABLE, + .write = memory_reclaim, }, - { - .name = "kmem.max_usage_in_bytes", - .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE), - .trigger = mem_cgroup_reset, - .read = mem_cgroup_read, - }, -#ifdef CONFIG_SLABINFO - { - .name = "kmem.slabinfo", - .read_seq_string = mem_cgroup_slabinfo_read, - }, -#endif -#endif - { }, /* terminate */ + { } /* terminate */ }; -#ifdef CONFIG_MEMCG_SWAP -static struct cftype memsw_cgroup_files[] = { - { - .name = "memsw.usage_in_bytes", - .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), - .read = mem_cgroup_read, - .register_event = mem_cgroup_usage_register_event, - .unregister_event = mem_cgroup_usage_unregister_event, - }, - { - .name = "memsw.max_usage_in_bytes", - .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE), - .trigger = mem_cgroup_reset, - .read = mem_cgroup_read, - }, - { - .name = "memsw.limit_in_bytes", - .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT), - .write_string = mem_cgroup_write, - .read = mem_cgroup_read, - }, - { - .name = "memsw.failcnt", - .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT), - .trigger = mem_cgroup_reset, - .read = mem_cgroup_read, - }, - { }, /* terminate */ -}; +struct cgroup_subsys memory_cgrp_subsys = { + .css_alloc = mem_cgroup_css_alloc, + .css_online = mem_cgroup_css_online, + .css_offline = mem_cgroup_css_offline, + .css_released = mem_cgroup_css_released, + .css_free = mem_cgroup_css_free, + .css_reset = mem_cgroup_css_reset, + .css_rstat_flush = mem_cgroup_css_rstat_flush, + .attach = mem_cgroup_attach, + .fork = mem_cgroup_fork, + .exit = mem_cgroup_exit, + .dfl_cftypes = memory_files, +#ifdef CONFIG_MEMCG_V1 + .legacy_cftypes = mem_cgroup_legacy_files, #endif -static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node) + .early_init = 0, +}; + +/** + * mem_cgroup_calculate_protection - check if memory consumption is in the normal range + * @root: the top ancestor of the sub-tree being checked + * @memcg: the memory cgroup to check + * + * WARNING: This function is not stateless! It can only be used as part + * of a top-down tree iteration, not for isolated queries. + */ +void mem_cgroup_calculate_protection(struct mem_cgroup *root, + struct mem_cgroup *memcg) { - struct mem_cgroup_per_node *pn; - struct mem_cgroup_per_zone *mz; - int zone, tmp = node; - /* - * This routine is called against possible nodes. - * But it's BUG to call kmalloc() against offline node. - * - * TODO: this routine can waste much memory for nodes which will - * never be onlined. It's better to use memory hotplug callback - * function. - */ - if (!node_state(node, N_NORMAL_MEMORY)) - tmp = -1; - pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp); - if (!pn) - return 1; + bool recursive_protection = + cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_RECURSIVE_PROT; - for (zone = 0; zone < MAX_NR_ZONES; zone++) { - mz = &pn->zoneinfo[zone]; - lruvec_init(&mz->lruvec); - mz->usage_in_excess = 0; - mz->on_tree = false; - mz->memcg = memcg; - } - memcg->nodeinfo[node] = pn; - return 0; + if (mem_cgroup_disabled()) + return; + + if (!root) + root = root_mem_cgroup; + + page_counter_calculate_protection(&root->memory, &memcg->memory, recursive_protection); } -static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node) +static int charge_memcg(struct folio *folio, struct mem_cgroup *memcg, + gfp_t gfp) { - kfree(memcg->nodeinfo[node]); + int ret; + + ret = try_charge(memcg, gfp, folio_nr_pages(folio)); + if (ret) + goto out; + + css_get(&memcg->css); + commit_charge(folio, memcg); + memcg1_commit_charge(folio, memcg); +out: + return ret; } -static struct mem_cgroup *mem_cgroup_alloc(void) +int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp) { struct mem_cgroup *memcg; - size_t size = memcg_size(); + int ret; - /* Can be very big if nr_node_ids is very big */ - if (size < PAGE_SIZE) - memcg = kzalloc(size, GFP_KERNEL); - else - memcg = vzalloc(size); + memcg = get_mem_cgroup_from_mm(mm); + ret = charge_memcg(folio, memcg, gfp); + css_put(&memcg->css); - if (!memcg) - return NULL; + return ret; +} - memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu); - if (!memcg->stat) - goto out_free; - spin_lock_init(&memcg->pcp_counter_lock); - return memcg; +/** + * mem_cgroup_charge_hugetlb - charge the memcg for a hugetlb folio + * @folio: folio being charged + * @gfp: reclaim mode + * + * This function is called when allocating a huge page folio, after the page has + * already been obtained and charged to the appropriate hugetlb cgroup + * controller (if it is enabled). + * + * Returns ENOMEM if the memcg is already full. + * Returns 0 if either the charge was successful, or if we skip the charging. + */ +int mem_cgroup_charge_hugetlb(struct folio *folio, gfp_t gfp) +{ + struct mem_cgroup *memcg = get_mem_cgroup_from_current(); + int ret = 0; -out_free: - if (size < PAGE_SIZE) - kfree(memcg); - else - vfree(memcg); - return NULL; + /* + * Even memcg does not account for hugetlb, we still want to update + * system-level stats via lruvec_stat_mod_folio. Return 0, and skip + * charging the memcg. + */ + if (mem_cgroup_disabled() || !memcg_accounts_hugetlb() || + !memcg || !cgroup_subsys_on_dfl(memory_cgrp_subsys)) + goto out; + + if (charge_memcg(folio, memcg, gfp)) + ret = -ENOMEM; + +out: + mem_cgroup_put(memcg); + return ret; } -/* - * At destroying mem_cgroup, references from swap_cgroup can remain. - * (scanning all at force_empty is too costly...) +/** + * mem_cgroup_swapin_charge_folio - Charge a newly allocated folio for swapin. + * @folio: folio to charge. + * @mm: mm context of the victim + * @gfp: reclaim mode + * @entry: swap entry for which the folio is allocated * - * Instead of clearing all references at force_empty, we remember - * the number of reference from swap_cgroup and free mem_cgroup when - * it goes down to 0. + * This function charges a folio allocated for swapin. Please call this before + * adding the folio to the swapcache. * - * Removal of cgroup itself succeeds regardless of refs from swap. + * Returns 0 on success. Otherwise, an error code is returned. */ - -static void __mem_cgroup_free(struct mem_cgroup *memcg) +int mem_cgroup_swapin_charge_folio(struct folio *folio, struct mm_struct *mm, + gfp_t gfp, swp_entry_t entry) { - int node; - size_t size = memcg_size(); + struct mem_cgroup *memcg; + unsigned short id; + int ret; - mem_cgroup_remove_from_trees(memcg); - free_css_id(&mem_cgroup_subsys, &memcg->css); + if (mem_cgroup_disabled()) + return 0; - for_each_node(node) - free_mem_cgroup_per_zone_info(memcg, node); + id = lookup_swap_cgroup_id(entry); + rcu_read_lock(); + memcg = mem_cgroup_from_id(id); + if (!memcg || !css_tryget_online(&memcg->css)) + memcg = get_mem_cgroup_from_mm(mm); + rcu_read_unlock(); - free_percpu(memcg->stat); + ret = charge_memcg(folio, memcg, gfp); - /* - * We need to make sure that (at least for now), the jump label - * destruction code runs outside of the cgroup lock. This is because - * get_online_cpus(), which is called from the static_branch update, - * can't be called inside the cgroup_lock. cpusets are the ones - * enforcing this dependency, so if they ever change, we might as well. - * - * schedule_work() will guarantee this happens. Be careful if you need - * to move this code around, and make sure it is outside - * the cgroup_lock. - */ - disarm_static_keys(memcg); - if (size < PAGE_SIZE) - kfree(memcg); - else - vfree(memcg); + css_put(&memcg->css); + return ret; } -/* - * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled. - */ -struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg) +struct uncharge_gather { + struct mem_cgroup *memcg; + unsigned long nr_memory; + unsigned long pgpgout; + unsigned long nr_kmem; + int nid; +}; + +static inline void uncharge_gather_clear(struct uncharge_gather *ug) { - if (!memcg->res.parent) - return NULL; - return mem_cgroup_from_res_counter(memcg->res.parent, res); + memset(ug, 0, sizeof(*ug)); } -EXPORT_SYMBOL(parent_mem_cgroup); -static void __init mem_cgroup_soft_limit_tree_init(void) +static void uncharge_batch(const struct uncharge_gather *ug) { - struct mem_cgroup_tree_per_node *rtpn; - struct mem_cgroup_tree_per_zone *rtpz; - int tmp, node, zone; - - for_each_node(node) { - tmp = node; - if (!node_state(node, N_NORMAL_MEMORY)) - tmp = -1; - rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp); - BUG_ON(!rtpn); - - soft_limit_tree.rb_tree_per_node[node] = rtpn; - - for (zone = 0; zone < MAX_NR_ZONES; zone++) { - rtpz = &rtpn->rb_tree_per_zone[zone]; - rtpz->rb_root = RB_ROOT; - spin_lock_init(&rtpz->lock); + if (ug->nr_memory) { + memcg_uncharge(ug->memcg, ug->nr_memory); + if (ug->nr_kmem) { + mod_memcg_state(ug->memcg, MEMCG_KMEM, -ug->nr_kmem); + memcg1_account_kmem(ug->memcg, -ug->nr_kmem); } + memcg1_oom_recover(ug->memcg); } + + memcg1_uncharge_batch(ug->memcg, ug->pgpgout, ug->nr_memory, ug->nid); + + /* drop reference from uncharge_folio */ + css_put(&ug->memcg->css); } -static struct cgroup_subsys_state * __ref -mem_cgroup_css_alloc(struct cgroup *cont) +static void uncharge_folio(struct folio *folio, struct uncharge_gather *ug) { + long nr_pages; struct mem_cgroup *memcg; - long error = -ENOMEM; - int node; + struct obj_cgroup *objcg; + + VM_BUG_ON_FOLIO(folio_test_lru(folio), folio); + + /* + * Nobody should be changing or seriously looking at + * folio memcg or objcg at this point, we have fully + * exclusive access to the folio. + */ + if (folio_memcg_kmem(folio)) { + objcg = __folio_objcg(folio); + /* + * This get matches the put at the end of the function and + * kmem pages do not hold memcg references anymore. + */ + memcg = get_mem_cgroup_from_objcg(objcg); + } else { + memcg = __folio_memcg(folio); + } - memcg = mem_cgroup_alloc(); if (!memcg) - return ERR_PTR(error); + return; - for_each_node(node) - if (alloc_mem_cgroup_per_zone_info(memcg, node)) - goto free_out; + if (ug->memcg != memcg) { + if (ug->memcg) { + uncharge_batch(ug); + uncharge_gather_clear(ug); + } + ug->memcg = memcg; + ug->nid = folio_nid(folio); - /* root ? */ - if (cont->parent == NULL) { - root_mem_cgroup = memcg; - res_counter_init(&memcg->res, NULL); - res_counter_init(&memcg->memsw, NULL); - res_counter_init(&memcg->kmem, NULL); + /* pairs with css_put in uncharge_batch */ + css_get(&memcg->css); } - memcg->last_scanned_node = MAX_NUMNODES; - INIT_LIST_HEAD(&memcg->oom_notify); - memcg->move_charge_at_immigrate = 0; - mutex_init(&memcg->thresholds_lock); - spin_lock_init(&memcg->move_lock); - vmpressure_init(&memcg->vmpressure); + nr_pages = folio_nr_pages(folio); - return &memcg->css; + if (folio_memcg_kmem(folio)) { + ug->nr_memory += nr_pages; + ug->nr_kmem += nr_pages; -free_out: - __mem_cgroup_free(memcg); - return ERR_PTR(error); + folio->memcg_data = 0; + obj_cgroup_put(objcg); + } else { + /* LRU pages aren't accounted at the root level */ + if (!mem_cgroup_is_root(memcg)) + ug->nr_memory += nr_pages; + ug->pgpgout++; + + WARN_ON_ONCE(folio_unqueue_deferred_split(folio)); + folio->memcg_data = 0; + } + + css_put(&memcg->css); } -static int -mem_cgroup_css_online(struct cgroup *cont) +void __mem_cgroup_uncharge(struct folio *folio) { - struct mem_cgroup *memcg, *parent; - int error = 0; + struct uncharge_gather ug; - if (!cont->parent) - return 0; + /* Don't touch folio->lru of any random page, pre-check: */ + if (!folio_memcg_charged(folio)) + return; - mutex_lock(&memcg_create_mutex); - memcg = mem_cgroup_from_cont(cont); - parent = mem_cgroup_from_cont(cont->parent); + uncharge_gather_clear(&ug); + uncharge_folio(folio, &ug); + uncharge_batch(&ug); +} - memcg->use_hierarchy = parent->use_hierarchy; - memcg->oom_kill_disable = parent->oom_kill_disable; - memcg->swappiness = mem_cgroup_swappiness(parent); +void __mem_cgroup_uncharge_folios(struct folio_batch *folios) +{ + struct uncharge_gather ug; + unsigned int i; - if (parent->use_hierarchy) { - res_counter_init(&memcg->res, &parent->res); - res_counter_init(&memcg->memsw, &parent->memsw); - res_counter_init(&memcg->kmem, &parent->kmem); + uncharge_gather_clear(&ug); + for (i = 0; i < folios->nr; i++) + uncharge_folio(folios->folios[i], &ug); + if (ug.memcg) + uncharge_batch(&ug); +} - /* - * No need to take a reference to the parent because cgroup - * core guarantees its existence. - */ - } else { - res_counter_init(&memcg->res, NULL); - res_counter_init(&memcg->memsw, NULL); - res_counter_init(&memcg->kmem, NULL); - /* - * Deeper hierachy with use_hierarchy == false doesn't make - * much sense so let cgroup subsystem know about this - * unfortunate state in our controller. - */ - if (parent != root_mem_cgroup) - mem_cgroup_subsys.broken_hierarchy = true; +/** + * mem_cgroup_replace_folio - Charge a folio's replacement. + * @old: Currently circulating folio. + * @new: Replacement folio. + * + * Charge @new as a replacement folio for @old. @old will + * be uncharged upon free. + * + * Both folios must be locked, @new->mapping must be set up. + */ +void mem_cgroup_replace_folio(struct folio *old, struct folio *new) +{ + struct mem_cgroup *memcg; + long nr_pages = folio_nr_pages(new); + + VM_BUG_ON_FOLIO(!folio_test_locked(old), old); + VM_BUG_ON_FOLIO(!folio_test_locked(new), new); + VM_BUG_ON_FOLIO(folio_test_anon(old) != folio_test_anon(new), new); + VM_BUG_ON_FOLIO(folio_nr_pages(old) != nr_pages, new); + + if (mem_cgroup_disabled()) + return; + + /* Page cache replacement: new folio already charged? */ + if (folio_memcg_charged(new)) + return; + + memcg = folio_memcg(old); + VM_WARN_ON_ONCE_FOLIO(!memcg, old); + if (!memcg) + return; + + /* Force-charge the new page. The old one will be freed soon */ + if (!mem_cgroup_is_root(memcg)) { + page_counter_charge(&memcg->memory, nr_pages); + if (do_memsw_account()) + page_counter_charge(&memcg->memsw, nr_pages); } - error = memcg_init_kmem(memcg, &mem_cgroup_subsys); - mutex_unlock(&memcg_create_mutex); - return error; + css_get(&memcg->css); + commit_charge(new, memcg); + memcg1_commit_charge(new, memcg); } -/* - * Announce all parents that a group from their hierarchy is gone. +/** + * mem_cgroup_migrate - Transfer the memcg data from the old to the new folio. + * @old: Currently circulating folio. + * @new: Replacement folio. + * + * Transfer the memcg data from the old folio to the new folio for migration. + * The old folio's data info will be cleared. Note that the memory counters + * will remain unchanged throughout the process. + * + * Both folios must be locked, @new->mapping must be set up. */ -static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup *memcg) +void mem_cgroup_migrate(struct folio *old, struct folio *new) { - struct mem_cgroup *parent = memcg; + struct mem_cgroup *memcg; + + VM_BUG_ON_FOLIO(!folio_test_locked(old), old); + VM_BUG_ON_FOLIO(!folio_test_locked(new), new); + VM_BUG_ON_FOLIO(folio_test_anon(old) != folio_test_anon(new), new); + VM_BUG_ON_FOLIO(folio_nr_pages(old) != folio_nr_pages(new), new); + VM_BUG_ON_FOLIO(folio_test_lru(old), old); - while ((parent = parent_mem_cgroup(parent))) - mem_cgroup_iter_invalidate(parent); + if (mem_cgroup_disabled()) + return; + memcg = folio_memcg(old); /* - * if the root memcg is not hierarchical we have to check it - * explicitely. + * Note that it is normal to see !memcg for a hugetlb folio. + * For e.g, itt could have been allocated when memory_hugetlb_accounting + * was not selected. */ - if (!root_mem_cgroup->use_hierarchy) - mem_cgroup_iter_invalidate(root_mem_cgroup); + VM_WARN_ON_ONCE_FOLIO(!folio_test_hugetlb(old) && !memcg, old); + if (!memcg) + return; + + /* Transfer the charge and the css ref */ + commit_charge(new, memcg); + + /* Warning should never happen, so don't worry about refcount non-0 */ + WARN_ON_ONCE(folio_unqueue_deferred_split(old)); + old->memcg_data = 0; } -static void mem_cgroup_css_offline(struct cgroup *cont) +DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key); +EXPORT_SYMBOL(memcg_sockets_enabled_key); + +void mem_cgroup_sk_alloc(struct sock *sk) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + struct mem_cgroup *memcg; - kmem_cgroup_css_offline(memcg); + if (!mem_cgroup_sockets_enabled) + return; + + /* Do not associate the sock with unrelated interrupted task's memcg. */ + if (!in_task()) + return; - mem_cgroup_invalidate_reclaim_iterators(memcg); - mem_cgroup_reparent_charges(memcg); - mem_cgroup_destroy_all_caches(memcg); + rcu_read_lock(); + memcg = mem_cgroup_from_task(current); + if (mem_cgroup_is_root(memcg)) + goto out; + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg1_tcpmem_active(memcg)) + goto out; + if (css_tryget(&memcg->css)) + sk->sk_memcg = memcg; +out: + rcu_read_unlock(); } -static void mem_cgroup_css_free(struct cgroup *cont) +void mem_cgroup_sk_free(struct sock *sk) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + struct mem_cgroup *memcg = mem_cgroup_from_sk(sk); - memcg_destroy_kmem(memcg); - __mem_cgroup_free(memcg); + if (memcg) + css_put(&memcg->css); } -#ifdef CONFIG_MMU -/* Handlers for move charge at task migration. */ -#define PRECHARGE_COUNT_AT_ONCE 256 -static int mem_cgroup_do_precharge(unsigned long count) +void mem_cgroup_sk_inherit(const struct sock *sk, struct sock *newsk) { - int ret = 0; - int batch_count = PRECHARGE_COUNT_AT_ONCE; - struct mem_cgroup *memcg = mc.to; + struct mem_cgroup *memcg; - if (mem_cgroup_is_root(memcg)) { - mc.precharge += count; - /* we don't need css_get for root */ - return ret; - } - /* try to charge at once */ - if (count > 1) { - struct res_counter *dummy; - /* - * "memcg" cannot be under rmdir() because we've already checked - * by cgroup_lock_live_cgroup() that it is not removed and we - * are still under the same cgroup_mutex. So we can postpone - * css_get(). - */ - if (res_counter_charge(&memcg->res, PAGE_SIZE * count, &dummy)) - goto one_by_one; - if (do_swap_account && res_counter_charge(&memcg->memsw, - PAGE_SIZE * count, &dummy)) { - res_counter_uncharge(&memcg->res, PAGE_SIZE * count); - goto one_by_one; - } - mc.precharge += count; - return ret; - } -one_by_one: - /* fall back to one by one charge */ - while (count--) { - if (signal_pending(current)) { - ret = -EINTR; - break; - } - if (!batch_count--) { - batch_count = PRECHARGE_COUNT_AT_ONCE; - cond_resched(); - } - ret = __mem_cgroup_try_charge(NULL, - GFP_KERNEL, 1, &memcg, false); - if (ret) - /* mem_cgroup_clear_mc() will do uncharge later */ - return ret; - mc.precharge++; - } - return ret; + if (sk->sk_memcg == newsk->sk_memcg) + return; + + mem_cgroup_sk_free(newsk); + + memcg = mem_cgroup_from_sk(sk); + if (memcg) + css_get(&memcg->css); + + newsk->sk_memcg = sk->sk_memcg; } /** - * get_mctgt_type - get target type of moving charge - * @vma: the vma the pte to be checked belongs - * @addr: the address corresponding to the pte to be checked - * @ptent: the pte to be checked - * @target: the pointer the target page or swap ent will be stored(can be NULL) - * - * Returns - * 0(MC_TARGET_NONE): if the pte is not a target for move charge. - * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for - * move charge. if @target is not NULL, the page is stored in target->page - * with extra refcnt got(Callers should handle it). - * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a - * target for charge migration. if @target is not NULL, the entry is stored - * in target->ent. + * mem_cgroup_sk_charge - charge socket memory + * @sk: socket in memcg to charge + * @nr_pages: number of pages to charge + * @gfp_mask: reclaim mode * - * Called with pte lock held. + * Charges @nr_pages to @memcg. Returns %true if the charge fit within + * @memcg's configured limit, %false if it doesn't. */ -union mc_target { - struct page *page; - swp_entry_t ent; -}; - -enum mc_target_type { - MC_TARGET_NONE = 0, - MC_TARGET_PAGE, - MC_TARGET_SWAP, -}; - -static struct page *mc_handle_present_pte(struct vm_area_struct *vma, - unsigned long addr, pte_t ptent) +bool mem_cgroup_sk_charge(const struct sock *sk, unsigned int nr_pages, + gfp_t gfp_mask) { - struct page *page = vm_normal_page(vma, addr, ptent); + struct mem_cgroup *memcg = mem_cgroup_from_sk(sk); - if (!page || !page_mapped(page)) - return NULL; - if (PageAnon(page)) { - /* we don't move shared anon */ - if (!move_anon()) - return NULL; - } else if (!move_file()) - /* we ignore mapcount for file pages */ - return NULL; - if (!get_page_unless_zero(page)) - return NULL; + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) + return memcg1_charge_skmem(memcg, nr_pages, gfp_mask); - return page; + if (try_charge_memcg(memcg, gfp_mask, nr_pages) == 0) { + mod_memcg_state(memcg, MEMCG_SOCK, nr_pages); + return true; + } + + return false; } -#ifdef CONFIG_SWAP -static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, - unsigned long addr, pte_t ptent, swp_entry_t *entry) +/** + * mem_cgroup_sk_uncharge - uncharge socket memory + * @sk: socket in memcg to uncharge + * @nr_pages: number of pages to uncharge + */ +void mem_cgroup_sk_uncharge(const struct sock *sk, unsigned int nr_pages) { - struct page *page = NULL; - swp_entry_t ent = pte_to_swp_entry(ptent); + struct mem_cgroup *memcg = mem_cgroup_from_sk(sk); - if (!move_anon() || non_swap_entry(ent)) - return NULL; - /* - * Because lookup_swap_cache() updates some statistics counter, - * we call find_get_page() with swapper_space directly. - */ - page = find_get_page(swap_address_space(ent), ent.val); - if (do_swap_account) - entry->val = ent.val; + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) { + memcg1_uncharge_skmem(memcg, nr_pages); + return; + } + + mod_memcg_state(memcg, MEMCG_SOCK, -nr_pages); - return page; + refill_stock(memcg, nr_pages); } -#else -static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, - unsigned long addr, pte_t ptent, swp_entry_t *entry) + +static int __init cgroup_memory(char *s) { - return NULL; + char *token; + + while ((token = strsep(&s, ",")) != NULL) { + if (!*token) + continue; + if (!strcmp(token, "nosocket")) + cgroup_memory_nosocket = true; + if (!strcmp(token, "nokmem")) + cgroup_memory_nokmem = true; + if (!strcmp(token, "nobpf")) + cgroup_memory_nobpf = true; + } + return 1; } -#endif +__setup("cgroup.memory=", cgroup_memory); -static struct page *mc_handle_file_pte(struct vm_area_struct *vma, - unsigned long addr, pte_t ptent, swp_entry_t *entry) +/* + * Memory controller init before cgroup_init() initialize root_mem_cgroup. + * + * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this + * context because of lock dependencies (cgroup_lock -> cpu hotplug) but + * basically everything that doesn't depend on a specific mem_cgroup structure + * should be initialized from here. + */ +int __init mem_cgroup_init(void) { - struct page *page = NULL; - struct address_space *mapping; - pgoff_t pgoff; - - if (!vma->vm_file) /* anonymous vma */ - return NULL; - if (!move_file()) - return NULL; + unsigned int memcg_size; + int cpu; - mapping = vma->vm_file->f_mapping; - if (pte_none(ptent)) - pgoff = linear_page_index(vma, addr); - else /* pte_file(ptent) is true */ - pgoff = pte_to_pgoff(ptent); + /* + * Currently s32 type (can refer to struct batched_lruvec_stat) is + * used for per-memcg-per-cpu caching of per-node statistics. In order + * to work fine, we should make sure that the overfill threshold can't + * exceed S32_MAX / PAGE_SIZE. + */ + BUILD_BUG_ON(MEMCG_CHARGE_BATCH > S32_MAX / PAGE_SIZE); - /* page is moved even if it's not RSS of this task(page-faulted). */ - page = find_get_page(mapping, pgoff); + cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL, + memcg_hotplug_cpu_dead); -#ifdef CONFIG_SWAP - /* shmem/tmpfs may report page out on swap: account for that too. */ - if (radix_tree_exceptional_entry(page)) { - swp_entry_t swap = radix_to_swp_entry(page); - if (do_swap_account) - *entry = swap; - page = find_get_page(swap_address_space(swap), swap.val); + for_each_possible_cpu(cpu) { + INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work, + drain_local_memcg_stock); + INIT_WORK(&per_cpu_ptr(&obj_stock, cpu)->work, + drain_local_obj_stock); } -#endif - return page; + + memcg_size = struct_size_t(struct mem_cgroup, nodeinfo, nr_node_ids); + memcg_cachep = kmem_cache_create("mem_cgroup", memcg_size, 0, + SLAB_PANIC | SLAB_HWCACHE_ALIGN, NULL); + + memcg_pn_cachep = KMEM_CACHE(mem_cgroup_per_node, + SLAB_PANIC | SLAB_HWCACHE_ALIGN); + + return 0; } -static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma, - unsigned long addr, pte_t ptent, union mc_target *target) +#ifdef CONFIG_SWAP +/** + * __mem_cgroup_try_charge_swap - try charging swap space for a folio + * @folio: folio being added to swap + * @entry: swap entry to charge + * + * Try to charge @folio's memcg for the swap space at @entry. + * + * Returns 0 on success, -ENOMEM on failure. + */ +int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry) { - struct page *page = NULL; - struct page_cgroup *pc; - enum mc_target_type ret = MC_TARGET_NONE; - swp_entry_t ent = { .val = 0 }; + unsigned int nr_pages = folio_nr_pages(folio); + struct page_counter *counter; + struct mem_cgroup *memcg; - if (pte_present(ptent)) - page = mc_handle_present_pte(vma, addr, ptent); - else if (is_swap_pte(ptent)) - page = mc_handle_swap_pte(vma, addr, ptent, &ent); - else if (pte_none(ptent) || pte_file(ptent)) - page = mc_handle_file_pte(vma, addr, ptent, &ent); + if (do_memsw_account()) + return 0; - if (!page && !ent.val) - return ret; - if (page) { - pc = lookup_page_cgroup(page); - /* - * Do only loose check w/o page_cgroup lock. - * mem_cgroup_move_account() checks the pc is valid or not under - * the lock. - */ - if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) { - ret = MC_TARGET_PAGE; - if (target) - target->page = page; - } - if (!ret || !target) - put_page(page); + memcg = folio_memcg(folio); + + VM_WARN_ON_ONCE_FOLIO(!memcg, folio); + if (!memcg) + return 0; + + if (!entry.val) { + memcg_memory_event(memcg, MEMCG_SWAP_FAIL); + return 0; } - /* There is a swap entry and a page doesn't exist or isn't charged */ - if (ent.val && !ret && - css_id(&mc.from->css) == lookup_swap_cgroup_id(ent)) { - ret = MC_TARGET_SWAP; - if (target) - target->ent = ent; + + memcg = mem_cgroup_id_get_online(memcg); + + if (!mem_cgroup_is_root(memcg) && + !page_counter_try_charge(&memcg->swap, nr_pages, &counter)) { + memcg_memory_event(memcg, MEMCG_SWAP_MAX); + memcg_memory_event(memcg, MEMCG_SWAP_FAIL); + mem_cgroup_id_put(memcg); + return -ENOMEM; } - return ret; + + /* Get references for the tail pages, too */ + if (nr_pages > 1) + mem_cgroup_id_get_many(memcg, nr_pages - 1); + mod_memcg_state(memcg, MEMCG_SWAP, nr_pages); + + swap_cgroup_record(folio, mem_cgroup_id(memcg), entry); + + return 0; } -#ifdef CONFIG_TRANSPARENT_HUGEPAGE -/* - * We don't consider swapping or file mapped pages because THP does not - * support them for now. - * Caller should make sure that pmd_trans_huge(pmd) is true. +/** + * __mem_cgroup_uncharge_swap - uncharge swap space + * @entry: swap entry to uncharge + * @nr_pages: the amount of swap space to uncharge */ -static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma, - unsigned long addr, pmd_t pmd, union mc_target *target) +void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages) { - struct page *page = NULL; - struct page_cgroup *pc; - enum mc_target_type ret = MC_TARGET_NONE; + struct mem_cgroup *memcg; + unsigned short id; - page = pmd_page(pmd); - VM_BUG_ON(!page || !PageHead(page)); - if (!move_anon()) - return ret; - pc = lookup_page_cgroup(page); - if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) { - ret = MC_TARGET_PAGE; - if (target) { - get_page(page); - target->page = page; + id = swap_cgroup_clear(entry, nr_pages); + rcu_read_lock(); + memcg = mem_cgroup_from_id(id); + if (memcg) { + if (!mem_cgroup_is_root(memcg)) { + if (do_memsw_account()) + page_counter_uncharge(&memcg->memsw, nr_pages); + else + page_counter_uncharge(&memcg->swap, nr_pages); } + mod_memcg_state(memcg, MEMCG_SWAP, -nr_pages); + mem_cgroup_id_put_many(memcg, nr_pages); } - return ret; + rcu_read_unlock(); } -#else -static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma, - unsigned long addr, pmd_t pmd, union mc_target *target) + +long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) { - return MC_TARGET_NONE; + long nr_swap_pages = get_nr_swap_pages(); + + if (mem_cgroup_disabled() || do_memsw_account()) + return nr_swap_pages; + for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) + nr_swap_pages = min_t(long, nr_swap_pages, + READ_ONCE(memcg->swap.max) - + page_counter_read(&memcg->swap)); + return nr_swap_pages; } -#endif -static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, - unsigned long addr, unsigned long end, - struct mm_walk *walk) +bool mem_cgroup_swap_full(struct folio *folio) { - struct vm_area_struct *vma = walk->private; - pte_t *pte; - spinlock_t *ptl; + struct mem_cgroup *memcg; - if (pmd_trans_huge_lock(pmd, vma) == 1) { - if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE) - mc.precharge += HPAGE_PMD_NR; - spin_unlock(&vma->vm_mm->page_table_lock); - return 0; - } + VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); - if (pmd_trans_unstable(pmd)) - return 0; - pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); - for (; addr != end; pte++, addr += PAGE_SIZE) - if (get_mctgt_type(vma, addr, *pte, NULL)) - mc.precharge++; /* increment precharge temporarily */ - pte_unmap_unlock(pte - 1, ptl); - cond_resched(); + if (vm_swap_full()) + return true; + if (do_memsw_account()) + return false; - return 0; -} + memcg = folio_memcg(folio); + if (!memcg) + return false; -static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm) -{ - unsigned long precharge; - struct vm_area_struct *vma; + for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) { + unsigned long usage = page_counter_read(&memcg->swap); - down_read(&mm->mmap_sem); - for (vma = mm->mmap; vma; vma = vma->vm_next) { - struct mm_walk mem_cgroup_count_precharge_walk = { - .pmd_entry = mem_cgroup_count_precharge_pte_range, - .mm = mm, - .private = vma, - }; - if (is_vm_hugetlb_page(vma)) - continue; - walk_page_range(vma->vm_start, vma->vm_end, - &mem_cgroup_count_precharge_walk); + if (usage * 2 >= READ_ONCE(memcg->swap.high) || + usage * 2 >= READ_ONCE(memcg->swap.max)) + return true; } - up_read(&mm->mmap_sem); - precharge = mc.precharge; - mc.precharge = 0; - - return precharge; + return false; } -static int mem_cgroup_precharge_mc(struct mm_struct *mm) +static int __init setup_swap_account(char *s) { - unsigned long precharge = mem_cgroup_count_precharge(mm); + bool res; - VM_BUG_ON(mc.moving_task); - mc.moving_task = current; - return mem_cgroup_do_precharge(precharge); + if (!kstrtobool(s, &res) && !res) + pr_warn_once("The swapaccount=0 commandline option is deprecated " + "in favor of configuring swap control via cgroupfs. " + "Please report your usecase to linux-mm@kvack.org if you " + "depend on this functionality.\n"); + return 1; } +__setup("swapaccount=", setup_swap_account); -/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */ -static void __mem_cgroup_clear_mc(void) +static u64 swap_current_read(struct cgroup_subsys_state *css, + struct cftype *cft) { - struct mem_cgroup *from = mc.from; - struct mem_cgroup *to = mc.to; - int i; + struct mem_cgroup *memcg = mem_cgroup_from_css(css); - /* we must uncharge all the leftover precharges from mc.to */ - if (mc.precharge) { - __mem_cgroup_cancel_charge(mc.to, mc.precharge); - mc.precharge = 0; - } - /* - * we didn't uncharge from mc.from at mem_cgroup_move_account(), so - * we must uncharge here. - */ - if (mc.moved_charge) { - __mem_cgroup_cancel_charge(mc.from, mc.moved_charge); - mc.moved_charge = 0; - } - /* we must fixup refcnts and charges */ - if (mc.moved_swap) { - /* uncharge swap account from the old cgroup */ - if (!mem_cgroup_is_root(mc.from)) - res_counter_uncharge(&mc.from->memsw, - PAGE_SIZE * mc.moved_swap); + return (u64)page_counter_read(&memcg->swap) * PAGE_SIZE; +} - for (i = 0; i < mc.moved_swap; i++) - css_put(&mc.from->css); +static int swap_peak_show(struct seq_file *sf, void *v) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(sf)); - if (!mem_cgroup_is_root(mc.to)) { - /* - * we charged both to->res and to->memsw, so we should - * uncharge to->res. - */ - res_counter_uncharge(&mc.to->res, - PAGE_SIZE * mc.moved_swap); - } - /* we've already done css_get(mc.to) */ - mc.moved_swap = 0; - } - memcg_oom_recover(from); - memcg_oom_recover(to); - wake_up_all(&mc.waitq); + return peak_show(sf, v, &memcg->swap); } -static void mem_cgroup_clear_mc(void) +static ssize_t swap_peak_write(struct kernfs_open_file *of, char *buf, + size_t nbytes, loff_t off) { - struct mem_cgroup *from = mc.from; + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); - /* - * we must clear moving_task before waking up waiters at the end of - * task migration. - */ - mc.moving_task = NULL; - __mem_cgroup_clear_mc(); - spin_lock(&mc.lock); - mc.from = NULL; - mc.to = NULL; - spin_unlock(&mc.lock); - mem_cgroup_end_move(from); + return peak_write(of, buf, nbytes, off, &memcg->swap, + &memcg->swap_peaks); } -static int mem_cgroup_can_attach(struct cgroup *cgroup, - struct cgroup_taskset *tset) +static int swap_high_show(struct seq_file *m, void *v) { - struct task_struct *p = cgroup_taskset_first(tset); - int ret = 0; - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgroup); - unsigned long move_charge_at_immigrate; + return seq_puts_memcg_tunable(m, + READ_ONCE(mem_cgroup_from_seq(m)->swap.high)); +} - /* - * We are now commited to this value whatever it is. Changes in this - * tunable will only affect upcoming migrations, not the current one. - * So we need to save it, and keep it going. - */ - move_charge_at_immigrate = memcg->move_charge_at_immigrate; - if (move_charge_at_immigrate) { - struct mm_struct *mm; - struct mem_cgroup *from = mem_cgroup_from_task(p); +static ssize_t swap_high_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + unsigned long high; + int err; - VM_BUG_ON(from == memcg); + buf = strstrip(buf); + err = page_counter_memparse(buf, "max", &high); + if (err) + return err; - mm = get_task_mm(p); - if (!mm) - return 0; - /* We move charges only when we move a owner of the mm */ - if (mm->owner == p) { - VM_BUG_ON(mc.from); - VM_BUG_ON(mc.to); - VM_BUG_ON(mc.precharge); - VM_BUG_ON(mc.moved_charge); - VM_BUG_ON(mc.moved_swap); - mem_cgroup_start_move(from); - spin_lock(&mc.lock); - mc.from = from; - mc.to = memcg; - mc.immigrate_flags = move_charge_at_immigrate; - spin_unlock(&mc.lock); - /* We set mc.moving_task later */ - - ret = mem_cgroup_precharge_mc(mm); - if (ret) - mem_cgroup_clear_mc(); - } - mmput(mm); - } - return ret; + page_counter_set_high(&memcg->swap, high); + + return nbytes; } -static void mem_cgroup_cancel_attach(struct cgroup *cgroup, - struct cgroup_taskset *tset) +static int swap_max_show(struct seq_file *m, void *v) { - mem_cgroup_clear_mc(); + return seq_puts_memcg_tunable(m, + READ_ONCE(mem_cgroup_from_seq(m)->swap.max)); } -static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, - unsigned long addr, unsigned long end, - struct mm_walk *walk) +static ssize_t swap_max_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) { - int ret = 0; - struct vm_area_struct *vma = walk->private; - pte_t *pte; - spinlock_t *ptl; - enum mc_target_type target_type; - union mc_target target; - struct page *page; - struct page_cgroup *pc; + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + unsigned long max; + int err; - /* - * We don't take compound_lock() here but no race with splitting thp - * happens because: - * - if pmd_trans_huge_lock() returns 1, the relevant thp is not - * under splitting, which means there's no concurrent thp split, - * - if another thread runs into split_huge_page() just after we - * entered this if-block, the thread must wait for page table lock - * to be unlocked in __split_huge_page_splitting(), where the main - * part of thp split is not executed yet. - */ - if (pmd_trans_huge_lock(pmd, vma) == 1) { - if (mc.precharge < HPAGE_PMD_NR) { - spin_unlock(&vma->vm_mm->page_table_lock); - return 0; - } - target_type = get_mctgt_type_thp(vma, addr, *pmd, &target); - if (target_type == MC_TARGET_PAGE) { - page = target.page; - if (!isolate_lru_page(page)) { - pc = lookup_page_cgroup(page); - if (!mem_cgroup_move_account(page, HPAGE_PMD_NR, - pc, mc.from, mc.to)) { - mc.precharge -= HPAGE_PMD_NR; - mc.moved_charge += HPAGE_PMD_NR; - } - putback_lru_page(page); - } - put_page(page); - } - spin_unlock(&vma->vm_mm->page_table_lock); - return 0; - } + buf = strstrip(buf); + err = page_counter_memparse(buf, "max", &max); + if (err) + return err; - if (pmd_trans_unstable(pmd)) - return 0; -retry: - pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); - for (; addr != end; addr += PAGE_SIZE) { - pte_t ptent = *(pte++); - swp_entry_t ent; + xchg(&memcg->swap.max, max); - if (!mc.precharge) - break; + return nbytes; +} - switch (get_mctgt_type(vma, addr, ptent, &target)) { - case MC_TARGET_PAGE: - page = target.page; - if (isolate_lru_page(page)) - goto put; - pc = lookup_page_cgroup(page); - if (!mem_cgroup_move_account(page, 1, pc, - mc.from, mc.to)) { - mc.precharge--; - /* we uncharge from mc.from later. */ - mc.moved_charge++; - } - putback_lru_page(page); -put: /* get_mctgt_type() gets the page */ - put_page(page); - break; - case MC_TARGET_SWAP: - ent = target.ent; - if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) { - mc.precharge--; - /* we fixup refcnts and charges later. */ - mc.moved_swap++; - } - break; - default: - break; - } - } - pte_unmap_unlock(pte - 1, ptl); - cond_resched(); +static int swap_events_show(struct seq_file *m, void *v) +{ + struct mem_cgroup *memcg = mem_cgroup_from_seq(m); - if (addr != end) { - /* - * We have consumed all precharges we got in can_attach(). - * We try charge one by one, but don't do any additional - * charges to mc.to if we have failed in charge once in attach() - * phase. - */ - ret = mem_cgroup_do_precharge(1); - if (!ret) - goto retry; - } + seq_printf(m, "high %lu\n", + atomic_long_read(&memcg->memory_events[MEMCG_SWAP_HIGH])); + seq_printf(m, "max %lu\n", + atomic_long_read(&memcg->memory_events[MEMCG_SWAP_MAX])); + seq_printf(m, "fail %lu\n", + atomic_long_read(&memcg->memory_events[MEMCG_SWAP_FAIL])); - return ret; + return 0; } -static void mem_cgroup_move_charge(struct mm_struct *mm) +static struct cftype swap_files[] = { + { + .name = "swap.current", + .flags = CFTYPE_NOT_ON_ROOT, + .read_u64 = swap_current_read, + }, + { + .name = "swap.high", + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = swap_high_show, + .write = swap_high_write, + }, + { + .name = "swap.max", + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = swap_max_show, + .write = swap_max_write, + }, + { + .name = "swap.peak", + .flags = CFTYPE_NOT_ON_ROOT, + .open = peak_open, + .release = peak_release, + .seq_show = swap_peak_show, + .write = swap_peak_write, + }, + { + .name = "swap.events", + .flags = CFTYPE_NOT_ON_ROOT, + .file_offset = offsetof(struct mem_cgroup, swap_events_file), + .seq_show = swap_events_show, + }, + { } /* terminate */ +}; + +#ifdef CONFIG_ZSWAP +/** + * obj_cgroup_may_zswap - check if this cgroup can zswap + * @objcg: the object cgroup + * + * Check if the hierarchical zswap limit has been reached. + * + * This doesn't check for specific headroom, and it is not atomic + * either. But with zswap, the size of the allocation is only known + * once compression has occurred, and this optimistic pre-check avoids + * spending cycles on compression when there is already no room left + * or zswap is disabled altogether somewhere in the hierarchy. + */ +bool obj_cgroup_may_zswap(struct obj_cgroup *objcg) { - struct vm_area_struct *vma; + struct mem_cgroup *memcg, *original_memcg; + bool ret = true; - lru_add_drain_all(); -retry: - if (unlikely(!down_read_trylock(&mm->mmap_sem))) { - /* - * Someone who are holding the mmap_sem might be waiting in - * waitq. So we cancel all extra charges, wake up all waiters, - * and retry. Because we cancel precharges, we might not be able - * to move enough charges, but moving charge is a best-effort - * feature anyway, so it wouldn't be a big problem. - */ - __mem_cgroup_clear_mc(); - cond_resched(); - goto retry; - } - for (vma = mm->mmap; vma; vma = vma->vm_next) { - int ret; - struct mm_walk mem_cgroup_move_charge_walk = { - .pmd_entry = mem_cgroup_move_charge_pte_range, - .mm = mm, - .private = vma, - }; - if (is_vm_hugetlb_page(vma)) + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) + return true; + + original_memcg = get_mem_cgroup_from_objcg(objcg); + for (memcg = original_memcg; !mem_cgroup_is_root(memcg); + memcg = parent_mem_cgroup(memcg)) { + unsigned long max = READ_ONCE(memcg->zswap_max); + unsigned long pages; + + if (max == PAGE_COUNTER_MAX) continue; - ret = walk_page_range(vma->vm_start, vma->vm_end, - &mem_cgroup_move_charge_walk); - if (ret) - /* - * means we have consumed all precharges and failed in - * doing additional charge. Just abandon here. - */ + if (max == 0) { + ret = false; break; + } + + /* Force flush to get accurate stats for charging */ + __mem_cgroup_flush_stats(memcg, true); + pages = memcg_page_state(memcg, MEMCG_ZSWAP_B) / PAGE_SIZE; + if (pages < max) + continue; + ret = false; + break; } - up_read(&mm->mmap_sem); + mem_cgroup_put(original_memcg); + return ret; } -static void mem_cgroup_move_task(struct cgroup *cont, - struct cgroup_taskset *tset) +/** + * obj_cgroup_charge_zswap - charge compression backend memory + * @objcg: the object cgroup + * @size: size of compressed object + * + * This forces the charge after obj_cgroup_may_zswap() allowed + * compression and storage in zswap for this cgroup to go ahead. + */ +void obj_cgroup_charge_zswap(struct obj_cgroup *objcg, size_t size) { - struct task_struct *p = cgroup_taskset_first(tset); - struct mm_struct *mm = get_task_mm(p); + struct mem_cgroup *memcg; - if (mm) { - if (mc.to) - mem_cgroup_move_charge(mm); - mmput(mm); - } - if (mc.to) - mem_cgroup_clear_mc(); + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) + return; + + VM_WARN_ON_ONCE(!(current->flags & PF_MEMALLOC)); + + /* PF_MEMALLOC context, charging must succeed */ + if (obj_cgroup_charge(objcg, GFP_KERNEL, size)) + VM_WARN_ON_ONCE(1); + + rcu_read_lock(); + memcg = obj_cgroup_memcg(objcg); + mod_memcg_state(memcg, MEMCG_ZSWAP_B, size); + mod_memcg_state(memcg, MEMCG_ZSWAPPED, 1); + rcu_read_unlock(); } -#else /* !CONFIG_MMU */ -static int mem_cgroup_can_attach(struct cgroup *cgroup, - struct cgroup_taskset *tset) + +/** + * obj_cgroup_uncharge_zswap - uncharge compression backend memory + * @objcg: the object cgroup + * @size: size of compressed object + * + * Uncharges zswap memory on page in. + */ +void obj_cgroup_uncharge_zswap(struct obj_cgroup *objcg, size_t size) { - return 0; + struct mem_cgroup *memcg; + + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) + return; + + obj_cgroup_uncharge(objcg, size); + + rcu_read_lock(); + memcg = obj_cgroup_memcg(objcg); + mod_memcg_state(memcg, MEMCG_ZSWAP_B, -size); + mod_memcg_state(memcg, MEMCG_ZSWAPPED, -1); + rcu_read_unlock(); } -static void mem_cgroup_cancel_attach(struct cgroup *cgroup, - struct cgroup_taskset *tset) + +bool mem_cgroup_zswap_writeback_enabled(struct mem_cgroup *memcg) { + /* if zswap is disabled, do not block pages going to the swapping device */ + if (!zswap_is_enabled()) + return true; + + for (; memcg; memcg = parent_mem_cgroup(memcg)) + if (!READ_ONCE(memcg->zswap_writeback)) + return false; + + return true; } -static void mem_cgroup_move_task(struct cgroup *cont, - struct cgroup_taskset *tset) + +static u64 zswap_current_read(struct cgroup_subsys_state *css, + struct cftype *cft) { + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + + mem_cgroup_flush_stats(memcg); + return memcg_page_state(memcg, MEMCG_ZSWAP_B); } -#endif -/* - * Cgroup retains root cgroups across [un]mount cycles making it necessary - * to verify sane_behavior flag on each mount attempt. - */ -static void mem_cgroup_bind(struct cgroup *root) +static int zswap_max_show(struct seq_file *m, void *v) { - /* - * use_hierarchy is forced with sane_behavior. cgroup core - * guarantees that @root doesn't have any children, so turning it - * on for the root memcg is enough. - */ - if (cgroup_sane_behavior(root)) - mem_cgroup_from_cont(root)->use_hierarchy = true; + return seq_puts_memcg_tunable(m, + READ_ONCE(mem_cgroup_from_seq(m)->zswap_max)); } -struct cgroup_subsys mem_cgroup_subsys = { - .name = "memory", - .subsys_id = mem_cgroup_subsys_id, - .css_alloc = mem_cgroup_css_alloc, - .css_online = mem_cgroup_css_online, - .css_offline = mem_cgroup_css_offline, - .css_free = mem_cgroup_css_free, - .can_attach = mem_cgroup_can_attach, - .cancel_attach = mem_cgroup_cancel_attach, - .attach = mem_cgroup_move_task, - .bind = mem_cgroup_bind, - .base_cftypes = mem_cgroup_files, - .early_init = 0, - .use_id = 1, -}; +static ssize_t zswap_max_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + unsigned long max; + int err; -#ifdef CONFIG_MEMCG_SWAP -static int __init enable_swap_account(char *s) + buf = strstrip(buf); + err = page_counter_memparse(buf, "max", &max); + if (err) + return err; + + xchg(&memcg->zswap_max, max); + + return nbytes; +} + +static int zswap_writeback_show(struct seq_file *m, void *v) { - /* consider enabled if no parameter or 1 is given */ - if (!strcmp(s, "1")) - really_do_swap_account = 1; - else if (!strcmp(s, "0")) - really_do_swap_account = 0; - return 1; + struct mem_cgroup *memcg = mem_cgroup_from_seq(m); + + seq_printf(m, "%d\n", READ_ONCE(memcg->zswap_writeback)); + return 0; } -__setup("swapaccount=", enable_swap_account); -static void __init memsw_file_init(void) +static ssize_t zswap_writeback_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) { - WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys, memsw_cgroup_files)); + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + int zswap_writeback; + ssize_t parse_ret = kstrtoint(strstrip(buf), 0, &zswap_writeback); + + if (parse_ret) + return parse_ret; + + if (zswap_writeback != 0 && zswap_writeback != 1) + return -EINVAL; + + WRITE_ONCE(memcg->zswap_writeback, zswap_writeback); + return nbytes; } -static void __init enable_swap_cgroup(void) +static struct cftype zswap_files[] = { + { + .name = "zswap.current", + .flags = CFTYPE_NOT_ON_ROOT, + .read_u64 = zswap_current_read, + }, + { + .name = "zswap.max", + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = zswap_max_show, + .write = zswap_max_write, + }, + { + .name = "zswap.writeback", + .seq_show = zswap_writeback_show, + .write = zswap_writeback_write, + }, + { } /* terminate */ +}; +#endif /* CONFIG_ZSWAP */ + +static int __init mem_cgroup_swap_init(void) { - if (!mem_cgroup_disabled() && really_do_swap_account) { - do_swap_account = 1; - memsw_file_init(); - } + if (mem_cgroup_disabled()) + return 0; + + WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, swap_files)); +#ifdef CONFIG_MEMCG_V1 + WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, memsw_files)); +#endif +#ifdef CONFIG_ZSWAP + WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, zswap_files)); +#endif + return 0; } +subsys_initcall(mem_cgroup_swap_init); -#else -static void __init enable_swap_cgroup(void) +#endif /* CONFIG_SWAP */ + +bool mem_cgroup_node_allowed(struct mem_cgroup *memcg, int nid) { + return memcg ? cpuset_node_allowed(memcg->css.cgroup, nid) : true; } -#endif -/* - * subsys_initcall() for memory controller. - * - * Some parts like hotcpu_notifier() have to be initialized from this context - * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically - * everything that doesn't depend on a specific mem_cgroup structure should - * be initialized from here. - */ -static int __init mem_cgroup_init(void) +void mem_cgroup_show_protected_memory(struct mem_cgroup *memcg) { - hotcpu_notifier(memcg_cpu_hotplug_callback, 0); - enable_swap_cgroup(); - mem_cgroup_soft_limit_tree_init(); - memcg_stock_init(); - return 0; + if (mem_cgroup_disabled() || !cgroup_subsys_on_dfl(memory_cgrp_subsys)) + return; + + if (!memcg) + memcg = root_mem_cgroup; + + pr_warn("Memory cgroup min protection %lukB -- low protection %lukB", + K(atomic_long_read(&memcg->memory.children_min_usage)*PAGE_SIZE), + K(atomic_long_read(&memcg->memory.children_low_usage)*PAGE_SIZE)); } -subsys_initcall(mem_cgroup_init); |