| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* memcontrol.c - Memory Controller |
| * |
| * Copyright IBM Corporation, 2007 |
| * Author Balbir Singh <balbir@linux.vnet.ibm.com> |
| * |
| * Copyright 2007 OpenVZ SWsoft Inc |
| * Author: Pavel Emelianov <xemul@openvz.org> |
| * |
| * Memory thresholds |
| * Copyright (C) 2009 Nokia Corporation |
| * Author: Kirill A. Shutemov |
| * |
| * Kernel Memory Controller |
| * Copyright (C) 2012 Parallels Inc. and Google Inc. |
| * Authors: Glauber Costa and Suleiman Souhlal |
| * |
| * Native page reclaim |
| * Charge lifetime sanitation |
| * Lockless page tracking & accounting |
| * Unified hierarchy configuration model |
| * Copyright (C) 2015 Red Hat, Inc., Johannes Weiner |
| */ |
| |
| #include <linux/page_counter.h> |
| #include <linux/memcontrol.h> |
| #include <linux/cgroup.h> |
| #include <linux/pagewalk.h> |
| #include <linux/sched/mm.h> |
| #include <linux/shmem_fs.h> |
| #include <linux/hugetlb.h> |
| #include <linux/pagemap.h> |
| #include <linux/vm_event_item.h> |
| #include <linux/smp.h> |
| #include <linux/page-flags.h> |
| #include <linux/backing-dev.h> |
| #include <linux/bit_spinlock.h> |
| #include <linux/rcupdate.h> |
| #include <linux/limits.h> |
| #include <linux/export.h> |
| #include <linux/mutex.h> |
| #include <linux/rbtree.h> |
| #include <linux/slab.h> |
| #include <linux/swap.h> |
| #include <linux/swapops.h> |
| #include <linux/spinlock.h> |
| #include <linux/eventfd.h> |
| #include <linux/poll.h> |
| #include <linux/sort.h> |
| #include <linux/fs.h> |
| #include <linux/seq_file.h> |
| #include <linux/vmpressure.h> |
| #include <linux/mm_inline.h> |
| #include <linux/swap_cgroup.h> |
| #include <linux/cpu.h> |
| #include <linux/oom.h> |
| #include <linux/lockdep.h> |
| #include <linux/file.h> |
| #include <linux/tracehook.h> |
| #include <linux/psi.h> |
| #include <linux/seq_buf.h> |
| #include "internal.h" |
| #include <net/sock.h> |
| #include <net/ip.h> |
| #include "slab.h" |
| |
| #include <linux/uaccess.h> |
| |
| #include <trace/events/vmscan.h> |
| #include <trace/hooks/mm.h> |
| |
| struct cgroup_subsys memory_cgrp_subsys __read_mostly; |
| EXPORT_SYMBOL(memory_cgrp_subsys); |
| |
| struct mem_cgroup *root_mem_cgroup __read_mostly; |
| |
| /* Active memory cgroup to use from an interrupt context */ |
| DEFINE_PER_CPU(struct mem_cgroup *, int_active_memcg); |
| |
| /* Socket memory accounting disabled? */ |
| static bool cgroup_memory_nosocket; |
| |
| /* Kernel memory accounting disabled? */ |
| static bool cgroup_memory_nokmem; |
| |
| /* Whether the swap controller is active */ |
| #ifdef CONFIG_MEMCG_SWAP |
| bool cgroup_memory_noswap __read_mostly; |
| #else |
| #define cgroup_memory_noswap 1 |
| #endif |
| |
| #ifdef CONFIG_CGROUP_WRITEBACK |
| static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq); |
| #endif |
| |
| /* Whether legacy memory+swap accounting is active */ |
| static bool do_memsw_account(void) |
| { |
| return !cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_noswap; |
| } |
| |
| #define THRESHOLDS_EVENTS_TARGET 128 |
| #define SOFTLIMIT_EVENTS_TARGET 1024 |
| |
| /* |
| * Cgroups above their limits are maintained in a RB-Tree, independent of |
| * their hierarchy representation |
| */ |
| |
| struct mem_cgroup_tree_per_node { |
| struct rb_root rb_root; |
| struct rb_node *rb_rightmost; |
| spinlock_t lock; |
| }; |
| |
| struct mem_cgroup_tree { |
| struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES]; |
| }; |
| |
| static struct mem_cgroup_tree soft_limit_tree __read_mostly; |
| |
| /* for OOM */ |
| struct mem_cgroup_eventfd_list { |
| struct list_head list; |
| struct eventfd_ctx *eventfd; |
| }; |
| |
| /* |
| * cgroup_event represents events which userspace want to receive. |
| */ |
| struct mem_cgroup_event { |
| /* |
| * memcg which the event belongs to. |
| */ |
| struct mem_cgroup *memcg; |
| /* |
| * eventfd to signal userspace about the event. |
| */ |
| struct eventfd_ctx *eventfd; |
| /* |
| * Each of these stored in a list by the cgroup. |
| */ |
| struct list_head list; |
| /* |
| * register_event() callback will be used to add new userspace |
| * waiter for changes related to this event. Use eventfd_signal() |
| * on eventfd to send notification to userspace. |
| */ |
| int (*register_event)(struct mem_cgroup *memcg, |
| struct eventfd_ctx *eventfd, const char *args); |
| /* |
| * unregister_event() callback will be called when userspace closes |
| * the eventfd or on cgroup removing. This callback must be set, |
| * if you want provide notification functionality. |
| */ |
| void (*unregister_event)(struct mem_cgroup *memcg, |
| struct eventfd_ctx *eventfd); |
| /* |
| * All fields below needed to unregister event when |
| * userspace closes eventfd. |
| */ |
| poll_table pt; |
| wait_queue_head_t *wqh; |
| wait_queue_entry_t wait; |
| struct work_struct remove; |
| }; |
| |
| static void mem_cgroup_threshold(struct mem_cgroup *memcg); |
| static void mem_cgroup_oom_notify(struct mem_cgroup *memcg); |
| |
| /* Stuffs for move charges at task migration. */ |
| /* |
| * Types of charges to be moved. |
| */ |
| #define MOVE_ANON 0x1U |
| #define MOVE_FILE 0x2U |
| #define MOVE_MASK (MOVE_ANON | MOVE_FILE) |
| |
| /* "mc" and its members are protected by cgroup_mutex */ |
| static struct move_charge_struct { |
| spinlock_t lock; /* for from, to */ |
| struct mm_struct *mm; |
| struct mem_cgroup *from; |
| struct mem_cgroup *to; |
| unsigned long flags; |
| unsigned long precharge; |
| unsigned long moved_charge; |
| unsigned long moved_swap; |
| struct task_struct *moving_task; /* a task moving charges */ |
| wait_queue_head_t waitq; /* a waitq for other context */ |
| } mc = { |
| .lock = __SPIN_LOCK_UNLOCKED(mc.lock), |
| .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq), |
| }; |
| |
| /* |
| * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft |
| * limit reclaim to prevent infinite loops, if they ever occur. |
| */ |
| #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100 |
| #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2 |
| |
| /* for encoding cft->private value on file */ |
| enum res_type { |
| _MEM, |
| _MEMSWAP, |
| _OOM_TYPE, |
| _KMEM, |
| _TCP, |
| }; |
| |
| #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) |
| |
| /* |
| * Iteration constructs for visiting all cgroups (under a tree). If |
| * loops are exited prematurely (break), mem_cgroup_iter_break() must |
| * be used for reference counting. |
| */ |
| #define for_each_mem_cgroup_tree(iter, root) \ |
| for (iter = mem_cgroup_iter(root, NULL, NULL); \ |
| iter != NULL; \ |
| iter = mem_cgroup_iter(root, iter, NULL)) |
| |
| #define for_each_mem_cgroup(iter) \ |
| for (iter = mem_cgroup_iter(NULL, NULL, NULL); \ |
| iter != NULL; \ |
| iter = mem_cgroup_iter(NULL, iter, NULL)) |
| |
| static inline bool task_is_dying(void) |
| { |
| return tsk_is_oom_victim(current) || fatal_signal_pending(current) || |
| (current->flags & PF_EXITING); |
| } |
| |
| /* Some nice accessors for the vmpressure. */ |
| struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg) |
| { |
| if (!memcg) |
| memcg = root_mem_cgroup; |
| return &memcg->vmpressure; |
| } |
| |
| struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr) |
| { |
| return &container_of(vmpr, struct mem_cgroup, vmpressure)->css; |
| } |
| |
| #ifdef CONFIG_MEMCG_KMEM |
| static DEFINE_SPINLOCK(objcg_lock); |
| |
| static void obj_cgroup_release(struct percpu_ref *ref) |
| { |
| struct obj_cgroup *objcg = container_of(ref, struct obj_cgroup, refcnt); |
| struct mem_cgroup *memcg; |
| unsigned int nr_bytes; |
| unsigned int nr_pages; |
| unsigned long flags; |
| |
| /* |
| * 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(). |
| */ |
| nr_bytes = atomic_read(&objcg->nr_charged_bytes); |
| WARN_ON_ONCE(nr_bytes & (PAGE_SIZE - 1)); |
| nr_pages = nr_bytes >> PAGE_SHIFT; |
| |
| spin_lock_irqsave(&objcg_lock, flags); |
| memcg = obj_cgroup_memcg(objcg); |
| if (nr_pages) |
| __memcg_kmem_uncharge(memcg, nr_pages); |
| list_del(&objcg->list); |
| mem_cgroup_put(memcg); |
| spin_unlock_irqrestore(&objcg_lock, flags); |
| |
| percpu_ref_exit(ref); |
| kfree_rcu(objcg, rcu); |
| } |
| |
| static struct obj_cgroup *obj_cgroup_alloc(void) |
| { |
| struct obj_cgroup *objcg; |
| int ret; |
| |
| objcg = kzalloc(sizeof(struct obj_cgroup), GFP_KERNEL); |
| if (!objcg) |
| return NULL; |
| |
| 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 void memcg_reparent_objcgs(struct mem_cgroup *memcg, |
| struct mem_cgroup *parent) |
| { |
| struct obj_cgroup *objcg, *iter; |
| |
| objcg = rcu_replace_pointer(memcg->objcg, NULL, true); |
| |
| spin_lock_irq(&objcg_lock); |
| |
| /* Move active objcg to the parent's list */ |
| xchg(&objcg->memcg, parent); |
| css_get(&parent->css); |
| list_add(&objcg->list, &parent->objcg_list); |
| |
| /* Move already reparented objcgs to the parent's list */ |
| list_for_each_entry(iter, &memcg->objcg_list, list) { |
| css_get(&parent->css); |
| xchg(&iter->memcg, parent); |
| css_put(&memcg->css); |
| } |
| list_splice(&memcg->objcg_list, &parent->objcg_list); |
| |
| spin_unlock_irq(&objcg_lock); |
| |
| percpu_ref_kill(&objcg->refcnt); |
| } |
| |
| /* |
| * This will be used as a shrinker list's index. |
| * The main reason for not using cgroup id for this: |
| * this works better in sparse environments, where we have a lot of memcgs, |
| * but only a few kmem-limited. Or also, if we have, for instance, 200 |
| * memcgs, and none but the 200th is kmem-limited, we'd have to have a |
| * 200 entry array for that. |
| * |
| * The current size of the caches array is stored in memcg_nr_cache_ids. It |
| * will double each time we have to increase it. |
| */ |
| static DEFINE_IDA(memcg_cache_ida); |
| int memcg_nr_cache_ids; |
| |
| /* Protects memcg_nr_cache_ids */ |
| static DECLARE_RWSEM(memcg_cache_ids_sem); |
| |
| void memcg_get_cache_ids(void) |
| { |
| down_read(&memcg_cache_ids_sem); |
| } |
| |
| void memcg_put_cache_ids(void) |
| { |
| up_read(&memcg_cache_ids_sem); |
| } |
| |
| /* |
| * MIN_SIZE is different than 1, because we would like to avoid going through |
| * the alloc/free process all the time. In a small machine, 4 kmem-limited |
| * cgroups is a reasonable guess. In the future, it could be a parameter or |
| * tunable, but that is strictly not necessary. |
| * |
| * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get |
| * this constant directly from cgroup, but it is understandable that this is |
| * better kept as an internal representation in cgroup.c. In any case, the |
| * cgrp_id space is not getting any smaller, and we don't have to necessarily |
| * increase ours as well if it increases. |
| */ |
| #define MEMCG_CACHES_MIN_SIZE 4 |
| #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX |
| |
| /* |
| * A lot of the calls to the cache allocation functions are expected to be |
| * inlined by the compiler. Since the calls to memcg_slab_pre_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 |
| */ |
| DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key); |
| EXPORT_SYMBOL(memcg_kmem_enabled_key); |
| #endif |
| |
| static int memcg_shrinker_map_size; |
| static DEFINE_MUTEX(memcg_shrinker_map_mutex); |
| |
| static void memcg_free_shrinker_map_rcu(struct rcu_head *head) |
| { |
| kvfree(container_of(head, struct memcg_shrinker_map, rcu)); |
| } |
| |
| static int memcg_expand_one_shrinker_map(struct mem_cgroup *memcg, |
| int size, int old_size) |
| { |
| struct memcg_shrinker_map *new, *old; |
| int nid; |
| |
| lockdep_assert_held(&memcg_shrinker_map_mutex); |
| |
| for_each_node(nid) { |
| old = rcu_dereference_protected( |
| mem_cgroup_nodeinfo(memcg, nid)->shrinker_map, true); |
| /* Not yet online memcg */ |
| if (!old) |
| return 0; |
| |
| new = kvmalloc_node(sizeof(*new) + size, GFP_KERNEL, nid); |
| if (!new) |
| return -ENOMEM; |
| |
| /* Set all old bits, clear all new bits */ |
| memset(new->map, (int)0xff, old_size); |
| memset((void *)new->map + old_size, 0, size - old_size); |
| |
| rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_map, new); |
| call_rcu(&old->rcu, memcg_free_shrinker_map_rcu); |
| } |
| |
| return 0; |
| } |
| |
| static void memcg_free_shrinker_maps(struct mem_cgroup *memcg) |
| { |
| struct mem_cgroup_per_node *pn; |
| struct memcg_shrinker_map *map; |
| int nid; |
| |
| if (mem_cgroup_is_root(memcg)) |
| return; |
| |
| for_each_node(nid) { |
| pn = mem_cgroup_nodeinfo(memcg, nid); |
| map = rcu_dereference_protected(pn->shrinker_map, true); |
| if (map) |
| kvfree(map); |
| rcu_assign_pointer(pn->shrinker_map, NULL); |
| } |
| } |
| |
| static int memcg_alloc_shrinker_maps(struct mem_cgroup *memcg) |
| { |
| struct memcg_shrinker_map *map; |
| int nid, size, ret = 0; |
| |
| if (mem_cgroup_is_root(memcg)) |
| return 0; |
| |
| mutex_lock(&memcg_shrinker_map_mutex); |
| size = memcg_shrinker_map_size; |
| for_each_node(nid) { |
| map = kvzalloc_node(sizeof(*map) + size, GFP_KERNEL, nid); |
| if (!map) { |
| memcg_free_shrinker_maps(memcg); |
| ret = -ENOMEM; |
| break; |
| } |
| rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_map, map); |
| } |
| mutex_unlock(&memcg_shrinker_map_mutex); |
| |
| return ret; |
| } |
| |
| int memcg_expand_shrinker_maps(int new_id) |
| { |
| int size, old_size, ret = 0; |
| struct mem_cgroup *memcg; |
| |
| size = DIV_ROUND_UP(new_id + 1, BITS_PER_LONG) * sizeof(unsigned long); |
| old_size = memcg_shrinker_map_size; |
| if (size <= old_size) |
| return 0; |
| |
| mutex_lock(&memcg_shrinker_map_mutex); |
| if (!root_mem_cgroup) |
| goto unlock; |
| |
| for_each_mem_cgroup(memcg) { |
| if (mem_cgroup_is_root(memcg)) |
| continue; |
| ret = memcg_expand_one_shrinker_map(memcg, size, old_size); |
| if (ret) { |
| mem_cgroup_iter_break(NULL, memcg); |
| goto unlock; |
| } |
| } |
| unlock: |
| if (!ret) |
| memcg_shrinker_map_size = size; |
| mutex_unlock(&memcg_shrinker_map_mutex); |
| return ret; |
| } |
| |
| void memcg_set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id) |
| { |
| if (shrinker_id >= 0 && memcg && !mem_cgroup_is_root(memcg)) { |
| struct memcg_shrinker_map *map; |
| |
| rcu_read_lock(); |
| map = rcu_dereference(memcg->nodeinfo[nid]->shrinker_map); |
| /* Pairs with smp mb in shrink_slab() */ |
| smp_mb__before_atomic(); |
| set_bit(shrinker_id, map->map); |
| rcu_read_unlock(); |
| } |
| } |
| |
| /** |
| * mem_cgroup_css_from_page - css of the memcg associated with a page |
| * @page: page of interest |
| * |
| * If memcg is bound to the default hierarchy, css of the memcg associated |
| * with @page is returned. The returned css remains associated with @page |
| * 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_page(struct page *page) |
| { |
| struct mem_cgroup *memcg; |
| |
| memcg = page->mem_cgroup; |
| |
| if (!memcg || !cgroup_subsys_on_dfl(memory_cgrp_subsys)) |
| memcg = root_mem_cgroup; |
| |
| return &memcg->css; |
| } |
| |
| /** |
| * 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; |
| |
| rcu_read_lock(); |
| memcg = page->mem_cgroup; |
| |
| /* |
| * The lowest bit set means that memcg isn't a valid |
| * memcg pointer, but a obj_cgroups pointer. |
| * In this case the page is shared and doesn't belong |
| * to any specific memory cgroup. |
| */ |
| if ((unsigned long) memcg & 0x1UL) |
| memcg = NULL; |
| |
| 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; |
| } |
| |
| static struct mem_cgroup_per_node * |
| mem_cgroup_page_nodeinfo(struct mem_cgroup *memcg, struct page *page) |
| { |
| int nid = page_to_nid(page); |
| |
| return memcg->nodeinfo[nid]; |
| } |
| |
| static struct mem_cgroup_tree_per_node * |
| soft_limit_tree_node(int nid) |
| { |
| return soft_limit_tree.rb_tree_per_node[nid]; |
| } |
| |
| static struct mem_cgroup_tree_per_node * |
| soft_limit_tree_from_page(struct page *page) |
| { |
| int nid = page_to_nid(page); |
| |
| return soft_limit_tree.rb_tree_per_node[nid]; |
| } |
| |
| static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz, |
| struct mem_cgroup_tree_per_node *mctz, |
| unsigned long new_usage_in_excess) |
| { |
| struct rb_node **p = &mctz->rb_root.rb_node; |
| struct rb_node *parent = NULL; |
| struct mem_cgroup_per_node *mz_node; |
| bool rightmost = true; |
| |
| if (mz->on_tree) |
| return; |
| |
| mz->usage_in_excess = new_usage_in_excess; |
| if (!mz->usage_in_excess) |
| return; |
| while (*p) { |
| parent = *p; |
| mz_node = rb_entry(parent, struct mem_cgroup_per_node, |
| tree_node); |
| if (mz->usage_in_excess < mz_node->usage_in_excess) { |
| p = &(*p)->rb_left; |
| rightmost = false; |
| } |
| |
| /* |
| * 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; |
| } |
| |
| if (rightmost) |
| mctz->rb_rightmost = &mz->tree_node; |
| |
| rb_link_node(&mz->tree_node, parent, p); |
| rb_insert_color(&mz->tree_node, &mctz->rb_root); |
| mz->on_tree = true; |
| } |
| |
| static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz, |
| struct mem_cgroup_tree_per_node *mctz) |
| { |
| if (!mz->on_tree) |
| return; |
| |
| if (&mz->tree_node == mctz->rb_rightmost) |
| mctz->rb_rightmost = rb_prev(&mz->tree_node); |
| |
| rb_erase(&mz->tree_node, &mctz->rb_root); |
| mz->on_tree = false; |
| } |
| |
| static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz, |
| struct mem_cgroup_tree_per_node *mctz) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&mctz->lock, flags); |
| __mem_cgroup_remove_exceeded(mz, mctz); |
| spin_unlock_irqrestore(&mctz->lock, flags); |
| } |
| |
| static unsigned long soft_limit_excess(struct mem_cgroup *memcg) |
| { |
| unsigned long nr_pages = page_counter_read(&memcg->memory); |
| unsigned long soft_limit = READ_ONCE(memcg->soft_limit); |
| unsigned long excess = 0; |
| |
| if (nr_pages > soft_limit) |
| excess = nr_pages - soft_limit; |
| |
| return excess; |
| } |
| |
| static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page) |
| { |
| unsigned long excess; |
| struct mem_cgroup_per_node *mz; |
| struct mem_cgroup_tree_per_node *mctz; |
| |
| mctz = soft_limit_tree_from_page(page); |
| if (!mctz) |
| return; |
| /* |
| * Necessary to update all ancestors when hierarchy is used. |
| * because their event counter is not touched. |
| */ |
| for (; memcg; memcg = parent_mem_cgroup(memcg)) { |
| mz = mem_cgroup_page_nodeinfo(memcg, page); |
| excess = soft_limit_excess(memcg); |
| /* |
| * We have to update the tree if mz is on RB-tree or |
| * mem is over its softlimit. |
| */ |
| if (excess || mz->on_tree) { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&mctz->lock, flags); |
| /* if on-tree, remove it */ |
| if (mz->on_tree) |
| __mem_cgroup_remove_exceeded(mz, mctz); |
| /* |
| * Insert again. mz->usage_in_excess will be updated. |
| * If excess is 0, no tree ops. |
| */ |
| __mem_cgroup_insert_exceeded(mz, mctz, excess); |
| spin_unlock_irqrestore(&mctz->lock, flags); |
| } |
| } |
| } |
| |
| static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg) |
| { |
| struct mem_cgroup_tree_per_node *mctz; |
| struct mem_cgroup_per_node *mz; |
| int nid; |
| |
| for_each_node(nid) { |
| mz = mem_cgroup_nodeinfo(memcg, nid); |
| mctz = soft_limit_tree_node(nid); |
| if (mctz) |
| mem_cgroup_remove_exceeded(mz, mctz); |
| } |
| } |
| |
| static struct mem_cgroup_per_node * |
| __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz) |
| { |
| struct mem_cgroup_per_node *mz; |
| |
| retry: |
| mz = NULL; |
| if (!mctz->rb_rightmost) |
| goto done; /* Nothing to reclaim from */ |
| |
| mz = rb_entry(mctz->rb_rightmost, |
| struct mem_cgroup_per_node, tree_node); |
| /* |
| * Remove the node now but someone else can add it back, |
| * we will to add it back at the end of reclaim to its correct |
| * position in the tree. |
| */ |
| __mem_cgroup_remove_exceeded(mz, mctz); |
| if (!soft_limit_excess(mz->memcg) || |
| !css_tryget(&mz->memcg->css)) |
| goto retry; |
| done: |
| return mz; |
| } |
| |
| static struct mem_cgroup_per_node * |
| mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz) |
| { |
| struct mem_cgroup_per_node *mz; |
| |
| spin_lock_irq(&mctz->lock); |
| mz = __mem_cgroup_largest_soft_limit_node(mctz); |
| spin_unlock_irq(&mctz->lock); |
| return mz; |
| } |
| |
| /** |
| * __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 |
| */ |
| void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val) |
| { |
| long x, threshold = MEMCG_CHARGE_BATCH; |
| |
| if (mem_cgroup_disabled()) |
| return; |
| |
| if (memcg_stat_item_in_bytes(idx)) |
| threshold <<= PAGE_SHIFT; |
| |
| x = val + __this_cpu_read(memcg->vmstats_percpu->stat[idx]); |
| if (unlikely(abs(x) > threshold)) { |
| struct mem_cgroup *mi; |
| |
| /* |
| * Batch local counters to keep them in sync with |
| * the hierarchical ones. |
| */ |
| __this_cpu_add(memcg->vmstats_local->stat[idx], x); |
| for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) |
| atomic_long_add(x, &mi->vmstats[idx]); |
| x = 0; |
| } |
| __this_cpu_write(memcg->vmstats_percpu->stat[idx], x); |
| } |
| |
| static struct mem_cgroup_per_node * |
| parent_nodeinfo(struct mem_cgroup_per_node *pn, int nid) |
| { |
| struct mem_cgroup *parent; |
| |
| parent = parent_mem_cgroup(pn->memcg); |
| if (!parent) |
| return NULL; |
| return mem_cgroup_nodeinfo(parent, nid); |
| } |
| |
| void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx, |
| int val) |
| { |
| struct mem_cgroup_per_node *pn; |
| struct mem_cgroup *memcg; |
| long x, threshold = MEMCG_CHARGE_BATCH; |
| |
| pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec); |
| memcg = pn->memcg; |
| |
| /* Update memcg */ |
| __mod_memcg_state(memcg, idx, val); |
| |
| /* Update lruvec */ |
| __this_cpu_add(pn->lruvec_stat_local->count[idx], val); |
| |
| if (vmstat_item_in_bytes(idx)) |
| threshold <<= PAGE_SHIFT; |
| |
| x = val + __this_cpu_read(pn->lruvec_stat_cpu->count[idx]); |
| if (unlikely(abs(x) > threshold)) { |
| pg_data_t *pgdat = lruvec_pgdat(lruvec); |
| struct mem_cgroup_per_node *pi; |
| |
| for (pi = pn; pi; pi = parent_nodeinfo(pi, pgdat->node_id)) |
| atomic_long_add(x, &pi->lruvec_stat[idx]); |
| x = 0; |
| } |
| __this_cpu_write(pn->lruvec_stat_cpu->count[idx], x); |
| } |
| |
| /** |
| * __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) |
| { |
| /* Update node */ |
| __mod_node_page_state(lruvec_pgdat(lruvec), idx, val); |
| |
| /* Update memcg and lruvec */ |
| if (!mem_cgroup_disabled()) |
| __mod_memcg_lruvec_state(lruvec, idx, val); |
| } |
| |
| void __mod_lruvec_slab_state(void *p, enum node_stat_item idx, int val) |
| { |
| pg_data_t *pgdat = page_pgdat(virt_to_page(p)); |
| struct mem_cgroup *memcg; |
| struct lruvec *lruvec; |
| |
| rcu_read_lock(); |
| memcg = mem_cgroup_from_obj(p); |
| |
| /* |
| * 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(); |
| } |
| |
| void mod_memcg_obj_state(void *p, int idx, int val) |
| { |
| struct mem_cgroup *memcg; |
| |
| rcu_read_lock(); |
| memcg = mem_cgroup_from_obj(p); |
| if (memcg) |
| mod_memcg_state(memcg, idx, val); |
| rcu_read_unlock(); |
| } |
| |
| /** |
| * __count_memcg_events - account VM events in a cgroup |
| * @memcg: the memory cgroup |
| * @idx: the event item |
| * @count: the number of events that occured |
| */ |
| void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx, |
| unsigned long count) |
| { |
| unsigned long x; |
| |
| if (mem_cgroup_disabled()) |
| return; |
| |
| x = count + __this_cpu_read(memcg->vmstats_percpu->events[idx]); |
| if (unlikely(x > MEMCG_CHARGE_BATCH)) { |
| struct mem_cgroup *mi; |
| |
| /* |
| * Batch local counters to keep them in sync with |
| * the hierarchical ones. |
| */ |
| __this_cpu_add(memcg->vmstats_local->events[idx], x); |
| for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) |
| atomic_long_add(x, &mi->vmevents[idx]); |
| x = 0; |
| } |
| __this_cpu_write(memcg->vmstats_percpu->events[idx], x); |
| } |
| |
| static unsigned long memcg_events(struct mem_cgroup *memcg, int event) |
| { |
| return atomic_long_read(&memcg->vmevents[event]); |
| } |
| |
| static unsigned long memcg_events_local(struct mem_cgroup *memcg, int event) |
| { |
| long x = 0; |
| int cpu; |
| |
| for_each_possible_cpu(cpu) |
| x += per_cpu(memcg->vmstats_local->events[event], cpu); |
| return x; |
| } |
| |
| static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, |
| struct page *page, |
| int nr_pages) |
| { |
| /* pagein of a big page is an event. So, ignore page size */ |
| if (nr_pages > 0) |
| __count_memcg_events(memcg, PGPGIN, 1); |
| else { |
| __count_memcg_events(memcg, PGPGOUT, 1); |
| nr_pages = -nr_pages; /* for event */ |
| } |
| |
| __this_cpu_add(memcg->vmstats_percpu->nr_page_events, nr_pages); |
| } |
| |
| static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, |
| enum mem_cgroup_events_target target) |
| { |
| unsigned long val, next; |
| |
| val = __this_cpu_read(memcg->vmstats_percpu->nr_page_events); |
| next = __this_cpu_read(memcg->vmstats_percpu->targets[target]); |
| /* from time_after() in jiffies.h */ |
| if ((long)(next - 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; |
| default: |
| break; |
| } |
| __this_cpu_write(memcg->vmstats_percpu->targets[target], next); |
| return true; |
| } |
| return false; |
| } |
| |
| /* |
| * Check events in order. |
| * |
| */ |
| static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) |
| { |
| /* threshold event is triggered in finer grain than soft limit */ |
| if (unlikely(mem_cgroup_event_ratelimit(memcg, |
| MEM_CGROUP_TARGET_THRESH))) { |
| bool do_softlimit; |
| |
| do_softlimit = mem_cgroup_event_ratelimit(memcg, |
| MEM_CGROUP_TARGET_SOFTLIMIT); |
| mem_cgroup_threshold(memcg); |
| if (unlikely(do_softlimit)) |
| mem_cgroup_update_tree(memcg, page); |
| } |
| } |
| |
| struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) |
| { |
| /* |
| * mm_update_next_owner() may clear mm->owner to NULL |
| * if it races with swapoff, page migration, etc. |
| * So this can be called with p == NULL. |
| */ |
| if (unlikely(!p)) |
| return NULL; |
| |
| return mem_cgroup_from_css(task_css(p, memory_cgrp_id)); |
| } |
| EXPORT_SYMBOL(mem_cgroup_from_task); |
| |
| /** |
| * 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. Otherwise |
| * root_mem_cgroup is returned. However 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; |
| |
| rcu_read_lock(); |
| do { |
| /* |
| * Page cache insertions can happen withou an |
| * actual mm context, e.g. during disk probing |
| * on boot, loopback IO, acct() writes etc. |
| */ |
| if (unlikely(!mm)) |
| memcg = root_mem_cgroup; |
| else { |
| memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); |
| if (unlikely(!memcg)) |
| memcg = root_mem_cgroup; |
| } |
| } while (!css_tryget(&memcg->css)); |
| rcu_read_unlock(); |
| return memcg; |
| } |
| EXPORT_SYMBOL(get_mem_cgroup_from_mm); |
| |
| /** |
| * get_mem_cgroup_from_page: Obtain a reference on given page's memcg. |
| * @page: page from which memcg should be extracted. |
| * |
| * Obtain a reference on page->memcg and returns it if successful. Otherwise |
| * root_mem_cgroup is returned. |
| */ |
| struct mem_cgroup *get_mem_cgroup_from_page(struct page *page) |
| { |
| struct mem_cgroup *memcg = page->mem_cgroup; |
| |
| if (mem_cgroup_disabled()) |
| return NULL; |
| |
| rcu_read_lock(); |
| /* Page should not get uncharged and freed memcg under us. */ |
| if (!memcg || WARN_ON_ONCE(!css_tryget(&memcg->css))) |
| memcg = root_mem_cgroup; |
| rcu_read_unlock(); |
| return memcg; |
| } |
| EXPORT_SYMBOL(get_mem_cgroup_from_page); |
| |
| static __always_inline struct mem_cgroup *active_memcg(void) |
| { |
| if (in_interrupt()) |
| return this_cpu_read(int_active_memcg); |
| else |
| return current->active_memcg; |
| } |
| |
| static __always_inline struct mem_cgroup *get_active_memcg(void) |
| { |
| struct mem_cgroup *memcg; |
| |
| rcu_read_lock(); |
| memcg = active_memcg(); |
| /* remote memcg must hold a ref. */ |
| if (memcg && WARN_ON_ONCE(!css_tryget(&memcg->css))) |
| memcg = root_mem_cgroup; |
| rcu_read_unlock(); |
| |
| return memcg; |
| } |
| |
| static __always_inline bool memcg_kmem_bypass(void) |
| { |
| /* Allow remote memcg charging from any context. */ |
| if (unlikely(active_memcg())) |
| return false; |
| |
| /* Memcg to charge can't be determined. */ |
| if (in_interrupt() || !current->mm || (current->flags & PF_KTHREAD)) |
| return true; |
| |
| return false; |
| } |
| |
| /** |
| * If active memcg is set, do not fallback to current->mm->memcg. |
| */ |
| static __always_inline struct mem_cgroup *get_mem_cgroup_from_current(void) |
| { |
| if (memcg_kmem_bypass()) |
| return NULL; |
| |
| if (unlikely(active_memcg())) |
| return get_active_memcg(); |
| |
| return get_mem_cgroup_from_mm(current->mm); |
| } |
| |
| /** |
| * mem_cgroup_iter - iterate over memory cgroup hierarchy |
| * @root: hierarchy root |
| * @prev: previously returned memcg, NULL on first invocation |
| * @reclaim: cookie for shared reclaim walks, NULL for full walks |
| * |
| * Returns references to children of the hierarchy below @root, or |
| * @root itself, or %NULL after a full round-trip. |
| * |
| * Caller must pass the return value in @prev on subsequent |
| * invocations for reference counting, or use mem_cgroup_iter_break() |
| * to cancel a hierarchy walk before the round-trip is complete. |
| * |
| * Reclaimers can specify a 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_reclaim_iter *iter; |
| struct cgroup_subsys_state *css = NULL; |
| struct mem_cgroup *memcg = NULL; |
| struct mem_cgroup *pos = NULL; |
| |
| if (mem_cgroup_disabled()) |
| return NULL; |
| |
| if (!root) |
| root = root_mem_cgroup; |
| |
| if (prev && !reclaim) |
| pos = prev; |
| |
| if (!root->use_hierarchy && root != root_mem_cgroup) { |
| if (prev) |
| goto out; |
| return root; |
| } |
| |
| rcu_read_lock(); |
| |
| if (reclaim) { |
| struct mem_cgroup_per_node *mz; |
| |
| mz = mem_cgroup_nodeinfo(root, reclaim->pgdat->node_id); |
| iter = &mz->iter; |
| |
| if (prev && reclaim->generation != iter->generation) |
| goto out_unlock; |
| |
| while (1) { |
| pos = READ_ONCE(iter->position); |
| if (!pos || css_tryget(&pos->css)) |
| break; |
| /* |
| * css reference reached zero, so iter->position will |
| * be cleared by ->css_released. However, we should not |
| * rely on this happening soon, because ->css_released |
| * is called from a work queue, and by busy-waiting we |
| * might block it. So we clear iter->position right |
| * away. |
| */ |
| (void)cmpxchg(&iter->position, pos, NULL); |
| } |
| } |
| |
| if (pos) |
| css = &pos->css; |
| |
| for (;;) { |
| css = css_next_descendant_pre(css, &root->css); |
| if (!css) { |
| /* |
| * Reclaimers share the hierarchy walk, and a |
| * new one might jump in right at the end of |
| * the hierarchy - make sure they see at least |
| * one group and restart from the beginning. |
| */ |
| if (!prev) |
| continue; |
| break; |
| } |
| |
| /* |
| * Verify the css and acquire a reference. The root |
| * is provided by the caller, so we know it's alive |
| * and kicking, and don't take an extra reference. |
| */ |
| memcg = mem_cgroup_from_css(css); |
| |
| if (css == &root->css) |
| break; |
| |
| if (css_tryget(css)) |
| break; |
| |
| memcg = NULL; |
| } |
| |
| 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. |
| */ |
| (void)cmpxchg(&iter->position, pos, memcg); |
| |
| if (pos) |
| css_put(&pos->css); |
| |
| if (!memcg) |
| iter->generation++; |
| else if (!prev) |
| reclaim->generation = iter->generation; |
| } |
| |
| out_unlock: |
| rcu_read_unlock(); |
| out: |
| if (prev && prev != root) |
| css_put(&prev->css); |
| |
| return memcg; |
| } |
| |
| /** |
| * mem_cgroup_iter_break - abort a hierarchy walk prematurely |
| * @root: hierarchy root |
| * @prev: last visited hierarchy member as returned by mem_cgroup_iter() |
| */ |
| void mem_cgroup_iter_break(struct mem_cgroup *root, |
| struct mem_cgroup *prev) |
| { |
| if (!root) |
| root = root_mem_cgroup; |
| if (prev && prev != root) |
| css_put(&prev->css); |
| } |
| |
| 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; |
| |
| for_each_node(nid) { |
| mz = mem_cgroup_nodeinfo(from, nid); |
| iter = &mz->iter; |
| cmpxchg(&iter->position, dead_memcg, NULL); |
| } |
| } |
| |
| static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg) |
| { |
| struct mem_cgroup *memcg = dead_memcg; |
| struct mem_cgroup *last; |
| |
| do { |
| __invalidate_reclaim_iterators(memcg, dead_memcg); |
| last = memcg; |
| } while ((memcg = parent_mem_cgroup(memcg))); |
| |
| /* |
| * When cgruop1 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 (last != root_mem_cgroup) |
| __invalidate_reclaim_iterators(root_mem_cgroup, |
| dead_memcg); |
| } |
| |
| /** |
| * 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 and returns the value. |
| * Otherwise, it will iterate over all tasks and return 0. |
| * |
| * This function must not be called for the root memory cgroup. |
| */ |
| int mem_cgroup_scan_tasks(struct mem_cgroup *memcg, |
| int (*fn)(struct task_struct *, void *), void *arg) |
| { |
| struct mem_cgroup *iter; |
| int ret = 0; |
| |
| BUG_ON(memcg == root_mem_cgroup); |
| |
| 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); |
| css_task_iter_end(&it); |
| if (ret) { |
| mem_cgroup_iter_break(memcg, iter); |
| break; |
| } |
| } |
| return ret; |
| } |
| |
| /** |
| * mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page |
| * @page: the page |
| * @pgdat: pgdat of the page |
| * |
| * This function relies on page->mem_cgroup being stable - see the |
| * access rules in commit_charge(). |
| */ |
| struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgdat) |
| { |
| struct mem_cgroup_per_node *mz; |
| struct mem_cgroup *memcg; |
| struct lruvec *lruvec; |
| |
| if (mem_cgroup_disabled()) { |
| lruvec = &pgdat->__lruvec; |
| goto out; |
| } |
| |
| memcg = page->mem_cgroup; |
| /* |
| * Swapcache readahead pages are added to the LRU - and |
| * possibly migrated - before they are charged. |
| */ |
| if (!memcg) |
| memcg = root_mem_cgroup; |
| |
| mz = mem_cgroup_page_nodeinfo(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->pgdat != pgdat)) |
| lruvec->pgdat = pgdat; |
| return lruvec; |
| } |
| |
| /** |
| * mem_cgroup_update_lru_size - account for adding or removing an lru page |
| * @lruvec: mem_cgroup per zone lru vector |
| * @lru: index of lru list the page is sitting on |
| * @zid: zone id of the accounted pages |
| * @nr_pages: positive when adding or negative when removing |
| * |
| * 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 (that ordering being |
| * so as to allow it to check that lru_size 0 is consistent with list_empty). |
| */ |
| void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru, |
| int zid, int nr_pages) |
| { |
| 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_node, lruvec); |
| lru_size = &mz->lru_zone_size[zid][lru]; |
| |
| if (nr_pages < 0) |
| *lru_size += nr_pages; |
| |
| 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 (nr_pages > 0) |
| *lru_size += nr_pages; |
| } |
| |
| /** |
| * mem_cgroup_margin - calculate chargeable space of a memory cgroup |
| * @memcg: the memory cgroup |
| * |
| * Returns the maximum amount of memory @mem can be charged with, in |
| * pages. |
| */ |
| static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg) |
| { |
| unsigned long margin = 0; |
| unsigned long count; |
| unsigned long limit; |
| |
| count = page_counter_read(&memcg->memory); |
| limit = READ_ONCE(memcg->memory.max); |
| if (count < limit) |
| margin = limit - count; |
| |
| 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 margin; |
| } |
| |
| /* |
| * A routine for checking "mem" is under move_account() or not. |
| * |
| * Checking a cgroup is mc.from or mc.to or under hierarchy of |
| * moving cgroups. This is for waiting at high-memory pressure |
| * caused by "move". |
| */ |
| static bool mem_cgroup_under_move(struct mem_cgroup *memcg) |
| { |
| struct mem_cgroup *from; |
| struct mem_cgroup *to; |
| bool ret = false; |
| /* |
| * Unlike task_move routines, we access mc.to, mc.from not under |
| * mutual exclusion by cgroup_mutex. Here, we take spinlock instead. |
| */ |
| spin_lock(&mc.lock); |
| from = mc.from; |
| to = mc.to; |
| if (!from) |
| goto unlock; |
| |
| ret = mem_cgroup_is_descendant(from, memcg) || |
| mem_cgroup_is_descendant(to, memcg); |
| unlock: |
| spin_unlock(&mc.lock); |
| return ret; |
| } |
| |
| static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg) |
| { |
| if (mc.moving_task && current != mc.moving_task) { |
| if (mem_cgroup_under_move(memcg)) { |
| DEFINE_WAIT(wait); |
| prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE); |
| /* moving charge context might have finished. */ |
| if (mc.moving_task) |
| schedule(); |
| finish_wait(&mc.waitq, &wait); |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| struct memory_stat { |
| const char *name; |
| unsigned int ratio; |
| unsigned int idx; |
| }; |
| |
| static struct memory_stat memory_stats[] = { |
| { "anon", PAGE_SIZE, NR_ANON_MAPPED }, |
| { "file", PAGE_SIZE, NR_FILE_PAGES }, |
| { "kernel_stack", 1024, NR_KERNEL_STACK_KB }, |
| { "percpu", 1, MEMCG_PERCPU_B }, |
| { "sock", PAGE_SIZE, MEMCG_SOCK }, |
| { "shmem", PAGE_SIZE, NR_SHMEM }, |
| { "file_mapped", PAGE_SIZE, NR_FILE_MAPPED }, |
| { "file_dirty", PAGE_SIZE, NR_FILE_DIRTY }, |
| { "file_writeback", PAGE_SIZE, NR_WRITEBACK }, |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| /* |
| * The ratio will be initialized in memory_stats_init(). Because |
| * on some architectures, the macro of HPAGE_PMD_SIZE is not |
| * constant(e.g. powerpc). |
| */ |
| { "anon_thp", 0, NR_ANON_THPS }, |
| #endif |
| { "inactive_anon", PAGE_SIZE, NR_INACTIVE_ANON }, |
| { "active_anon", PAGE_SIZE, NR_ACTIVE_ANON }, |
| { "inactive_file", PAGE_SIZE, NR_INACTIVE_FILE }, |
| { "active_file", PAGE_SIZE, NR_ACTIVE_FILE }, |
| { "unevictable", PAGE_SIZE, NR_UNEVICTABLE }, |
| |
| /* |
| * Note: The slab_reclaimable and slab_unreclaimable must be |
| * together and slab_reclaimable must be in front. |
| */ |
| { "slab_reclaimable", 1, NR_SLAB_RECLAIMABLE_B }, |
| { "slab_unreclaimable", 1, NR_SLAB_UNRECLAIMABLE_B }, |
| |
| /* The memory events */ |
| { "workingset_refault_anon", 1, WORKINGSET_REFAULT_ANON }, |
| { "workingset_refault_file", 1, WORKINGSET_REFAULT_FILE }, |
| { "workingset_activate_anon", 1, WORKINGSET_ACTIVATE_ANON }, |
| { "workingset_activate_file", 1, WORKINGSET_ACTIVATE_FILE }, |
| { "workingset_restore_anon", 1, WORKINGSET_RESTORE_ANON }, |
| { "workingset_restore_file", 1, WORKINGSET_RESTORE_FILE }, |
| { "workingset_nodereclaim", 1, WORKINGSET_NODERECLAIM }, |
| }; |
| |
| static int __init memory_stats_init(void) |
| { |
| int i; |
| |
| for (i = 0; i < ARRAY_SIZE(memory_stats); i++) { |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| if (memory_stats[i].idx == NR_ANON_THPS) |
| memory_stats[i].ratio = HPAGE_PMD_SIZE; |
| #endif |
| VM_BUG_ON(!memory_stats[i].ratio); |
| VM_BUG_ON(memory_stats[i].idx >= MEMCG_NR_STAT); |
| } |
| |
| return 0; |
| } |
| pure_initcall(memory_stats_init); |
| |
| static char *memory_stat_format(struct mem_cgroup *memcg) |
| { |
| struct seq_buf s; |
| int i; |
| |
| seq_buf_init(&s, kmalloc(PAGE_SIZE, GFP_KERNEL), PAGE_SIZE); |
| if (!s.buffer) |
| return NULL; |
| |
| /* |
| * 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: |
| */ |
| |
| for (i = 0; i < ARRAY_SIZE(memory_stats); i++) { |
| u64 size; |
| |
| size = memcg_page_state(memcg, memory_stats[i].idx); |
| size *= memory_stats[i].ratio; |
| 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(memcg, NR_SLAB_RECLAIMABLE_B) + |
| memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE_B); |
| seq_buf_printf(&s, "slab %llu\n", size); |
| } |
| } |
| |
| /* Accumulated memory events */ |
| |
| seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGFAULT), |
| memcg_events(memcg, PGFAULT)); |
| seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGMAJFAULT), |
| memcg_events(memcg, PGMAJFAULT)); |
| seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGREFILL), |
| memcg_events(memcg, PGREFILL)); |
| seq_buf_printf(&s, "pgscan %lu\n", |
| memcg_events(memcg, PGSCAN_KSWAPD) + |
| memcg_events(memcg, PGSCAN_DIRECT)); |
| seq_buf_printf(&s, "pgsteal %lu\n", |
| memcg_events(memcg, PGSTEAL_KSWAPD) + |
| memcg_events(memcg, PGSTEAL_DIRECT)); |
| seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGACTIVATE), |
| memcg_events(memcg, PGACTIVATE)); |
| seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGDEACTIVATE), |
| memcg_events(memcg, PGDEACTIVATE)); |
| seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGLAZYFREE), |
| memcg_events(memcg, PGLAZYFREE)); |
| seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGLAZYFREED), |
| memcg_events(memcg, PGLAZYFREED)); |
| |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| seq_buf_printf(&s, "%s %lu\n", vm_event_name(THP_FAULT_ALLOC), |
| memcg_events(memcg, THP_FAULT_ALLOC)); |
| seq_buf_printf(&s, "%s %lu\n", vm_event_name(THP_COLLAPSE_ALLOC), |
| memcg_events(memcg, THP_COLLAPSE_ALLOC)); |
| #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ |
| |
| /* The above should easily fit into one page */ |
| WARN_ON_ONCE(seq_buf_has_overflowed(&s)); |
| |
| return s.buffer; |
| } |
| |
| #define K(x) ((x) << (PAGE_SHIFT-10)) |
| /** |
| * 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_context(struct mem_cgroup *memcg, struct task_struct *p) |
| { |
| rcu_read_lock(); |
| |
| 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(); |
| } |
| |
| /** |
| * mem_cgroup_print_oom_meminfo: Print OOM memory information relevant to |
| * memory controller. |
| * @memcg: The memory cgroup that went over limit |
| */ |
| void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg) |
| { |
| char *buf; |
| |
| pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n", |
| K((u64)page_counter_read(&memcg->memory)), |
| K((u64)READ_ONCE(memcg->memory.max)), memcg->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)), memcg->swap.failcnt); |
| 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); |
| } |
| |
| pr_info("Memory cgroup stats for "); |
| pr_cont_cgroup_path(memcg->css.cgroup); |
| pr_cont(":"); |
| buf = memory_stat_format(memcg); |
| if (!buf) |
| return; |
| pr_info("%s", buf); |
| kfree(buf); |
| } |
| |
| /* |
| * Return the memory (and swap, if configured) limit for a memcg. |
| */ |
| unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg) |
| { |
| unsigned long max = READ_ONCE(memcg->memory.max); |
| |
| if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) { |
| if (mem_cgroup_swappiness(memcg)) |
| max += min(READ_ONCE(memcg->swap.max), |
| (unsigned long)total_swap_pages); |
| } else { /* v1 */ |
| if (mem_cgroup_swappiness(memcg)) { |
| /* Calculate swap excess capacity from memsw limit */ |
| unsigned long swap = READ_ONCE(memcg->memsw.max) - max; |
| |
| max += min(swap, (unsigned long)total_swap_pages); |
| } |
| } |
| return max; |
| } |
| |
| unsigned long mem_cgroup_size(struct mem_cgroup *memcg) |
| { |
| return page_counter_read(&memcg->memory); |
| } |
| |
| static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, |
| int order) |
| { |
| 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; |
| |
| 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 = task_is_dying() || out_of_memory(&oc); |
| |
| unlock: |
| mutex_unlock(&oom_lock); |
| return ret; |
| } |
| |
| static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg, |
| pg_data_t *pgdat, |
| 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 = { |
| .pgdat = pgdat, |
| }; |
| |
| excess = soft_limit_excess(root_memcg); |
| |
| while (1) { |
| victim = mem_cgroup_iter(root_memcg, victim, &reclaim); |
| if (!victim) { |
| loop++; |
| if (loop >= 2) { |
| /* |
| * If we have not been able to reclaim |
| * anything, it might because there are |
| * no reclaimable pages under this hierarchy |
| */ |
| if (!total) |
| break; |
| /* |
| * We want to do more targeted reclaim. |
| * excess >> 2 is not to excessive so as to |
| * reclaim too much, nor too less that we keep |
| * coming back to reclaim from this cgroup |
| */ |
| if (total >= (excess >> 2) || |
| (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) |
| break; |
| } |
| continue; |
| } |
| total += mem_cgroup_shrink_node(victim, gfp_mask, false, |
| pgdat, &nr_scanned); |
| *total_scanned += nr_scanned; |
| if (!soft_limit_excess(root_memcg)) |
| break; |
| } |
| mem_cgroup_iter_break(root_memcg, victim); |
| return total; |
| } |
| |
| #ifdef CONFIG_LOCKDEP |
| static struct lockdep_map memcg_oom_lock_dep_map = { |
| .name = "memcg_oom_lock", |
| }; |
| #endif |
| |
| static DEFINE_SPINLOCK(memcg_oom_lock); |
| |
| /* |
| * Check OOM-Killer is already running under our hierarchy. |
| * If someone is running, return false. |
| */ |
| static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg) |
| { |
| struct mem_cgroup *iter, *failed = NULL; |
| |
| spin_lock(&memcg_oom_lock); |
| |
| for_each_mem_cgroup_tree(iter, memcg) { |
| if (iter->oom_lock) { |
| /* |
| * this subtree of our hierarchy is already locked |
| * so we cannot give a lock. |
| */ |
| failed = iter; |
| mem_cgroup_iter_break(memcg, iter); |
| break; |
| } else |
| iter->oom_lock = true; |
| } |
| |
| if (failed) { |
| /* |
| * OK, we failed to lock the whole subtree so we have |
| * to clean up what we set up to the failing subtree |
| */ |
| for_each_mem_cgroup_tree(iter, memcg) { |
| if (iter == failed) { |
| mem_cgroup_iter_break(memcg, iter); |
| break; |
| } |
| iter->oom_lock = false; |
| } |
| } else |
| mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_); |
| |
| spin_unlock(&memcg_oom_lock); |
| |
| return !failed; |
| } |
| |
| static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg) |
| { |
| struct mem_cgroup *iter; |
| |
| spin_lock(&memcg_oom_lock); |
| mutex_release(&memcg_oom_lock_dep_map, _RET_IP_); |
| for_each_mem_cgroup_tree(iter, memcg) |
| iter->oom_lock = false; |
| spin_unlock(&memcg_oom_lock); |
| } |
| |
| static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg) |
| { |
| struct mem_cgroup *iter; |
| |
| spin_lock(&memcg_oom_lock); |
| for_each_mem_cgroup_tree(iter, memcg) |
| iter->under_oom++; |
| spin_unlock(&memcg_oom_lock); |
| } |
| |
| static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg) |
| { |
| struct mem_cgroup *iter; |
| |
| /* |
| * Be careful about under_oom underflows becase a child memcg |
| * could have been added after mem_cgroup_mark_under_oom. |
| */ |
| spin_lock(&memcg_oom_lock); |
| for_each_mem_cgroup_tree(iter, memcg) |
| if (iter->under_oom > 0) |
| iter->under_oom--; |
| spin_unlock(&memcg_oom_lock); |
| } |
| |
| static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq); |
| |
| struct oom_wait_info { |
| struct mem_cgroup *memcg; |
| wait_queue_entry_t wait; |
| }; |
| |
| static int memcg_oom_wake_function(wait_queue_entry_t *wait, |
| unsigned mode, int sync, void *arg) |
| { |
| struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg; |
| struct mem_cgroup *oom_wait_memcg; |
| struct oom_wait_info *oom_wait_info; |
| |
| oom_wait_info = container_of(wait, struct oom_wait_info, wait); |
| oom_wait_memcg = oom_wait_info->memcg; |
| |
| if (!mem_cgroup_is_descendant(wake_memcg, oom_wait_memcg) && |
| !mem_cgroup_is_descendant(oom_wait_memcg, wake_memcg)) |
| return 0; |
| return autoremove_wake_function(wait, mode, sync, arg); |
| } |
| |
| static void memcg_oom_recover(struct mem_cgroup *memcg) |
| { |
| /* |
| * For the following lockless ->under_oom test, the only required |
| * guarantee is that it must see the state asserted by an OOM when |
| * this function is called as a result of userland actions |
| * triggered by the notification of the OOM. This is trivially |
| * achieved by invoking mem_cgroup_mark_under_oom() before |
| * triggering notification. |
| */ |
| if (memcg && memcg->under_oom) |
| __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg); |
| } |
| |
| enum oom_status { |
| OOM_SUCCESS, |
| OOM_FAILED, |
| OOM_ASYNC, |
| OOM_SKIPPED |
| }; |
| |
| static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order) |
| { |
| enum oom_status ret; |
| bool locked; |
| |
| if (order > PAGE_ALLOC_COSTLY_ORDER) |
| return OOM_SKIPPED; |
| |
| memcg_memory_event(memcg, MEMCG_OOM); |
| |
| /* |
| * We are in the middle of the charge context here, so we |
| * don't want to block when potentially sitting on a callstack |
| * that holds all kinds of filesystem and mm locks. |
| * |
| * cgroup1 allows disabling the OOM killer and waiting for outside |
| * handling until the charge can succeed; remember the context and put |
| * the task to sleep at the end of the page fault when all locks are |
| * released. |
| * |
| * On the other hand, in-kernel OOM killer allows for an async victim |
| * memory reclaim (oom_reaper) and that means that we are not solely |
| * relying on the oom victim to make a forward progress and we can |
| * invoke the oom killer here. |
| * |
| * Please note that mem_cgroup_out_of_memory might fail to find a |
| * victim and then we have to bail out from the charge path. |
| */ |
| if (memcg->oom_kill_disable) { |
| if (!current->in_user_fault) |
| return OOM_SKIPPED; |
| css_get(&memcg->css); |
| current->memcg_in_oom = memcg; |
| current->memcg_oom_gfp_mask = mask; |
| current->memcg_oom_order = order; |
| |
| return OOM_ASYNC; |
| } |
| |
| mem_cgroup_mark_under_oom(memcg); |
| |
| locked = mem_cgroup_oom_trylock(memcg); |
| |
| if (locked) |
| mem_cgroup_oom_notify(memcg); |
| |
| mem_cgroup_unmark_under_oom(memcg); |
| if (mem_cgroup_out_of_memory(memcg, mask, order)) |
| ret = OOM_SUCCESS; |
| else |
| ret = OOM_FAILED; |
| |
| if (locked) |
| mem_cgroup_oom_unlock(memcg); |
| |
| return ret; |
| } |
| |
| /** |
| * mem_cgroup_oom_synchronize - complete memcg OOM handling |
| * @handle: actually kill/wait or just clean up the OOM state |
| * |
| * This has to be called at the end of a page fault if the memcg OOM |
| * handler was enabled. |
| * |
| * Memcg supports userspace OOM handling where failed allocations must |
| * sleep on a waitqueue until the userspace task resolves the |
| * situation. Sleeping directly in the charge context with all kinds |
| * of locks held is not a good idea, instead we remember an OOM state |
| * in the task and mem_cgroup_oom_synchronize() has to be called at |
| * the end of the page fault to complete the OOM handling. |
| * |
| * Returns %true if an ongoing memcg OOM situation was detected and |
| * completed, %false otherwise. |
| */ |
| bool mem_cgroup_oom_synchronize(bool handle) |
| { |
| struct mem_cgroup *memcg = current->memcg_in_oom; |
| struct oom_wait_info owait; |
| bool locked; |
| |
| /* OOM is global, do not handle */ |
| if (!memcg) |
| return false; |
| |
| if (!handle) |
| goto cleanup; |
| |
| owait.memcg = memcg; |
| owait.wait.flags = 0; |
| owait.wait.func = memcg_oom_wake_function; |
| owait.wait.private = current; |
| INIT_LIST_HEAD(&owait.wait.entry); |
| |
| prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE); |
| mem_cgroup_mark_under_oom(memcg); |
| |
| locked = mem_cgroup_oom_trylock(memcg); |
| |
| if (locked) |
| mem_cgroup_oom_notify(memcg); |
| |
| if (locked && !memcg->oom_kill_disable) { |
| mem_cgroup_unmark_under_oom(memcg); |
| finish_wait(&memcg_oom_waitq, &owait.wait); |
| mem_cgroup_out_of_memory(memcg, current->memcg_oom_gfp_mask, |
| current->memcg_oom_order); |
| } else { |
| schedule(); |
| mem_cgroup_unmark_under_oom(memcg); |
| finish_wait(&memcg_oom_waitq, &owait.wait); |
| } |
| |
| if (locked) { |
| mem_cgroup_oom_unlock(memcg); |
| /* |
| * There is no guarantee that an OOM-lock contender |
| * sees the wakeups triggered by the OOM kill |
| * uncharges. Wake any sleepers explicitely. |
| */ |
| memcg_oom_recover(memcg); |
| } |
| cleanup: |
| current->memcg_in_oom = NULL; |
| css_put(&memcg->css); |
| return true; |
| } |
| |
| /** |
| * 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 |
| * |
| * Returns a pointer to a memory cgroup, which has to be cleaned up |
| * by killing all belonging OOM-killable tasks. |
| * |
| * Caller has to call mem_cgroup_put() on the returned non-NULL memcg. |
| */ |
| struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim, |
| struct mem_cgroup *oom_domain) |
| { |
| struct mem_cgroup *oom_group = NULL; |
| struct mem_cgroup *memcg; |
| |
| if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) |
| return NULL; |
| |
| if (!oom_domain) |
| oom_domain = root_mem_cgroup; |
| |
| rcu_read_lock(); |
| |
| memcg = mem_cgroup_from_task(victim); |
| if (memcg == root_mem_cgroup) |
| goto out; |
| |
| /* |
| * 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 (unlikely(!mem_cgroup_is_descendant(memcg, oom_domain))) |
| goto out; |
| |
| /* |
| * 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 (; memcg; memcg = parent_mem_cgroup(memcg)) { |
| if (memcg->oom_group) |
| oom_group = memcg; |
| |
| if (memcg == oom_domain) |
| break; |
| } |
| |
| if (oom_group) |
| css_get(&oom_group->css); |
| out: |
| rcu_read_unlock(); |
| |
| return oom_group; |
| } |
| |
| void mem_cgroup_print_oom_group(struct mem_cgroup *memcg) |
| { |
| 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"); |
| } |
| |
| /** |
| * lock_page_memcg - lock a page->mem_cgroup binding |
| * @page: the page |
| * |
| * This function protects unlocked LRU pages from being moved to |
| * another cgroup. |
| * |
| * It ensures lifetime of the returned memcg. Caller is responsible |
| * for the lifetime of the page; __unlock_page_memcg() is available |
| * when @page might get freed inside the locked section. |
| */ |
| struct mem_cgroup *lock_page_memcg(struct page *page) |
| { |
| struct page *head = compound_head(page); /* rmap on tail pages */ |
| struct mem_cgroup *memcg; |
| unsigned long flags; |
| |
| /* |
| * The RCU lock is held throughout the transaction. The fast |
| * path can get away without acquiring the memcg->move_lock |
| * because page moving starts with an RCU grace period. |
| * |
| * The RCU lock also protects the memcg from being freed when |
| * the page state that is going to change is the only thing |
| * preventing the page itself from being freed. E.g. writeback |
| * doesn't hold a page reference and relies on PG_writeback to |
| * keep off truncation, migration and so forth. |
| */ |
| rcu_read_lock(); |
| |
| if (mem_cgroup_disabled()) |
| return NULL; |
| again: |
| memcg = head->mem_cgroup; |
| if (unlikely(!memcg)) |
| return NULL; |
| |
| if (atomic_read(&memcg->moving_account) <= 0) |
| return memcg; |
| |
| spin_lock_irqsave(&memcg->move_lock, flags); |
| if (memcg != head->mem_cgroup) { |
| spin_unlock_irqrestore(&memcg->move_lock, flags); |
| goto again; |
| } |
| |
| /* |
| * When charge migration first begins, we can have locked and |
| * unlocked page stat updates happening concurrently. Track |
| * the task who has the lock for unlock_page_memcg(). |
| */ |
| memcg->move_lock_task = current; |
| memcg->move_lock_flags = flags; |
| |
| return memcg; |
| } |
| EXPORT_SYMBOL(lock_page_memcg); |
| |
| /** |
| * __unlock_page_memcg - unlock and unpin a memcg |
| * @memcg: the memcg |
| * |
| * Unlock and unpin a memcg returned by lock_page_memcg(). |
| */ |
| void __unlock_page_memcg(struct mem_cgroup *memcg) |
| { |
| if (memcg && memcg->move_lock_task == current) { |
| unsigned long flags = memcg->move_lock_flags; |
| |
| memcg->move_lock_task = NULL; |
| memcg->move_lock_flags = 0; |
| |
| spin_unlock_irqrestore(&memcg->move_lock, flags); |
| } |
| |
| rcu_read_unlock(); |
| } |
| |
| /** |
| * unlock_page_memcg - unlock a page->mem_cgroup binding |
| * @page: the page |
| */ |
| void unlock_page_memcg(struct page *page) |
| { |
| struct page *head = compound_head(page); |
| |
| __unlock_page_memcg(head->mem_cgroup); |
| } |
| EXPORT_SYMBOL(unlock_page_memcg); |
| |
| struct memcg_stock_pcp { |
| struct mem_cgroup *cached; /* this never be root cgroup */ |
| unsigned int nr_pages; |
| |
| #ifdef CONFIG_MEMCG_KMEM |
| struct obj_cgroup *cached_objcg; |
| unsigned int nr_bytes; |
| #endif |
| |
| 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); |
| |
| #ifdef CONFIG_MEMCG_KMEM |
| static void drain_obj_stock(struct memcg_stock_pcp *stock); |
| static bool obj_stock_flush_required(struct memcg_stock_pcp *stock, |
| struct mem_cgroup *root_memcg); |
| |
| #else |
| static inline void drain_obj_stock(struct memcg_stock_pcp *stock) |
| { |
| } |
| static bool obj_stock_flush_required(struct memcg_stock_pcp *stock, |
| struct mem_cgroup *root_memcg) |
| { |
| return false; |
| } |
| #endif |
| |
| /** |
| * consume_stock: Try to consume stocked charge on this cpu. |
| * @memcg: memcg to consume from. |
| * @nr_pages: how many pages to charge. |
| * |
| * The charges will only happen if @memcg matches the current cpu's memcg |
| * stock, and at least @nr_pages are available in that stock. Failure to |
| * service an allocation will refill the stock. |
| * |
| * returns true if successful, false otherwise. |
| */ |
| static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages) |
| { |
| struct memcg_stock_pcp *stock; |
| unsigned long flags; |
| bool ret = false; |
| |
| if (nr_pages > MEMCG_CHARGE_BATCH) |
| return ret; |
| |
| local_irq_save(flags); |
| |
| stock = this_cpu_ptr(&memcg_stock); |
| if (memcg == stock->cached && stock->nr_pages >= nr_pages) { |
| stock->nr_pages -= nr_pages; |
| ret = true; |
| } |
| |
| local_irq_restore(flags); |
| |
| return ret; |
| } |
| |
| /* |
| * Returns stocks cached in percpu and reset cached information. |
| */ |
| static void drain_stock(struct memcg_stock_pcp *stock) |
| { |
| struct mem_cgroup *old = stock->cached; |
| |
| if (!old) |
| return; |
| |
| if (stock->nr_pages) { |
| page_counter_uncharge(&old->memory, stock->nr_pages); |
| if (do_memsw_account()) |
| page_counter_uncharge(&old->memsw, stock->nr_pages); |
| stock->nr_pages = 0; |
| } |
| |
| css_put(&old->css); |
| stock->cached = NULL; |
| } |
| |
| static void drain_local_stock(struct work_struct *dummy) |
| { |
| struct memcg_stock_pcp *stock; |
| unsigned long flags; |
| |
| /* |
| * The only protection from memory hotplug vs. drain_stock races is |
| * that we always operate on local CPU stock here with IRQ disabled |
| */ |
| local_irq_save(flags); |
| |
| stock = this_cpu_ptr(&memcg_stock); |
| drain_obj_stock(stock); |
| drain_stock(stock); |
| clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); |
| |
| local_irq_restore(flags); |
| } |
| |
| /* |
| * Cache charges(val) to local per_cpu area. |
| * This will be consumed by consume_stock() function, later. |
| */ |
| static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages) |
| { |
| struct memcg_stock_pcp *stock; |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| |
| stock = this_cpu_ptr(&memcg_stock); |
| if (stock->cached != memcg) { /* reset if necessary */ |
| drain_stock(stock); |
| css_get(&memcg->css); |
| stock->cached = memcg; |
| } |
| stock->nr_pages += nr_pages; |
| |
| if (stock->nr_pages > MEMCG_CHARGE_BATCH) |
| drain_stock(stock); |
| |
| local_irq_restore(flags); |
| } |
| |
| /* |
| * Drains all per-CPU charge caches for given root_memcg resp. subtree |
| * of the hierarchy under it. |
| */ |
| static void drain_all_stock(struct mem_cgroup *root_memcg) |
| { |
| int cpu, curcpu; |
| |
| /* If someone's already draining, avoid adding running more workers. */ |
| if (!mutex_trylock(&percpu_charge_mutex)) |
| return; |
| /* |
| * Notify other cpus that system-wide "drain" is running |
| * 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. |
| */ |
| curcpu = get_cpu(); |
| for_each_online_cpu(cpu) { |
| struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); |
| struct mem_cgroup *memcg; |
| bool flush = false; |
| |
| rcu_read_lock(); |
| memcg = stock->cached; |
| if (memcg && stock->nr_pages && |
| mem_cgroup_is_descendant(memcg, root_memcg)) |
| flush = true; |
| if (obj_stock_flush_required(stock, root_memcg)) |
| flush = true; |
| rcu_read_unlock(); |
| |
| if (flush && |
| !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(); |
| mutex_unlock(&percpu_charge_mutex); |
| } |
| |
| static int memcg_hotplug_cpu_dead(unsigned int cpu) |
| { |
| struct memcg_stock_pcp *stock; |
| struct mem_cgroup *memcg, *mi; |
| |
| stock = &per_cpu(memcg_stock, cpu); |
| drain_stock(stock); |
| |
| for_each_mem_cgroup(memcg) { |
| int i; |
| |
| for (i = 0; i < MEMCG_NR_STAT; i++) { |
| int nid; |
| long x; |
| |
| x = this_cpu_xchg(memcg->vmstats_percpu->stat[i], 0); |
| if (x) |
| for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) |
| atomic_long_add(x, &memcg->vmstats[i]); |
| |
| if (i >= NR_VM_NODE_STAT_ITEMS) |
| continue; |
| |
| for_each_node(nid) { |
| struct mem_cgroup_per_node *pn; |
| |
| pn = mem_cgroup_nodeinfo(memcg, nid); |
| x = this_cpu_xchg(pn->lruvec_stat_cpu->count[i], 0); |
| if (x) |
| do { |
| atomic_long_add(x, &pn->lruvec_stat[i]); |
| } while ((pn = parent_nodeinfo(pn, nid))); |
| } |
| } |
| |
| for (i = 0; i < NR_VM_EVENT_ITEMS; i++) { |
| long x; |
| |
| x = this_cpu_xchg(memcg->vmstats_percpu->events[i], 0); |
| if (x) |
| for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) |
| atomic_long_add(x, &memcg->vmevents[i]); |
| } |
| } |
| |
| return 0; |
| } |
| |
| static unsigned long reclaim_high(struct mem_cgroup *memcg, |
| unsigned int nr_pages, |
| gfp_t gfp_mask) |
| { |
| unsigned long nr_reclaimed = 0; |
| |
| do { |
| unsigned long pflags; |
| |
| if (page_counter_read(&memcg->memory) <= |
| READ_ONCE(memcg->memory.high)) |
| continue; |
| |
| memcg_memory_event(memcg, MEMCG_HIGH); |
| |
| psi_memstall_enter(&pflags); |
| nr_reclaimed += try_to_free_mem_cgroup_pages(memcg, nr_pages, |
| gfp_mask, true); |
| psi_memstall_leave(&pflags); |
| } while ((memcg = parent_mem_cgroup(memcg)) && |
| !mem_cgroup_is_root(memcg)); |
| |
| return nr_reclaimed; |
| } |
| |
| 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); |
| } |
| |
| /* |
| * 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 MEMCG_MAX_HIGH_DELAY_JIFFIES (2UL*HZ) |
| |
| /* |
| * 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. |
| * |
| * - 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. |
| * |
| * 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 | |
| * +-------+------------------------+ |
| */ |
| #define MEMCG_DELAY_PRECISION_SHIFT 20 |
| #define MEMCG_DELAY_SCALING_SHIFT 14 |
| |
| static u64 calculate_overage(unsigned long usage, unsigned long high) |
| { |
| u64 overage; |
| |
| if (usage <= high) |
| return 0; |
| |
| /* |
| * 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); |
| } |
| |
| static u64 mem_find_max_overage(struct mem_cgroup *memcg) |
| { |
| u64 overage, max_overage = 0; |
| |
| 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)); |
| |
| return max_overage; |
| } |
| |
| static u64 swap_find_max_overage(struct mem_cgroup *memcg) |
| { |
| u64 overage, max_overage = 0; |
| |
| 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)); |
| |
| return max_overage; |
| } |
| |
| /* |
| * 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 unsigned long calculate_high_delay(struct mem_cgroup *memcg, |
| unsigned int nr_pages, |
| u64 max_overage) |
| { |
| unsigned long penalty_jiffies; |
| |
| 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; |
| } |
| |
| /* |
| * Scheduled by try_charge() to be executed from the userland return path |
| * and reclaims memory over the high limit. |
| */ |
| void mem_cgroup_handle_over_high(void) |
| { |
| 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; |
| |
| if (likely(!nr_pages)) |
| return; |
| |
| memcg = get_mem_cgroup_from_mm(current->mm); |
| current->memcg_nr_pages_over_high = 0; |
| |
| retry_reclaim: |
| /* |
| * 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_KERNEL); |
| |
| /* |
| * memory.high is breached and reclaim is unable to keep up. Throttle |
| * allocators proactively to slow down excessive growth. |
| */ |
| penalty_jiffies = calculate_high_delay(memcg, nr_pages, |
| mem_find_max_overage(memcg)); |
| |
| penalty_jiffies += calculate_high_delay(memcg, nr_pages, |
| swap_find_max_overage(memcg)); |
| |
| /* |
| * 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); |
| |
| /* |
| * 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; |
| |
| /* |
| * 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; |
| } |
| |
| /* |
| * 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 try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, |
| unsigned int nr_pages) |
| { |
| 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; |
| enum oom_status oom_status; |
| unsigned long nr_reclaimed; |
| bool passed_oom = false; |
| bool may_swap = true; |
| bool drained = false; |
| unsigned long pflags; |
| |
| if (mem_cgroup_is_root(memcg)) |
| return 0; |
| retry: |
| if (consume_stock(memcg, nr_pages)) |
| return 0; |
| |
| 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); |
| may_swap = false; |
| } |
| |
| if (batch > nr_pages) { |
| batch = nr_pages; |
| goto retry; |
| } |
| |
| /* |
| * 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_ATOMIC) |
| goto force; |
| |
| /* |
| * 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; |
| |
| if (unlikely(task_in_memcg_oom(current))) |
| goto nomem; |
| |
| if (!gfpflags_allow_blocking(gfp_mask)) |
| goto nomem; |
| |
| memcg_memory_event(mem_over_limit, MEMCG_MAX); |
| |
| psi_memstall_enter(&pflags); |
| nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages, |
| gfp_mask, may_swap); |
| psi_memstall_leave(&pflags); |
| |
| if (mem_cgroup_margin(mem_over_limit) >= nr_pages) |
| goto retry; |
| |
| if (!drained) { |
| drain_all_stock(mem_over_limit); |
| drained = true; |
| goto retry; |
| } |
| |
| if (gfp_mask & __GFP_NORETRY) |
| goto nomem; |
| /* |
| * Even though the limit is exceeded at this point, reclaim |
| * may have been able to free some pages. Retry the charge |
| * before killing the task. |
| * |
| * Only for regular pages, though: huge pages are rather |
| * unlikely to succeed so close to the limit, and we fall back |
| * to regular pages anyway in case of failure. |
| */ |
| if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER)) |
| goto retry; |
| /* |
| * At task move, charge accounts can be doubly counted. So, it's |
| * better to wait until the end of task_move if something is going on. |
| */ |
| if (mem_cgroup_wait_acct_move(mem_over_limit)) |
| goto retry; |
| |
| if (nr_retries--) |
| goto retry; |
| |
| if (gfp_mask & __GFP_RETRY_MAYFAIL) |
| goto nomem; |
| |
| if (gfp_mask & __GFP_NOFAIL) |
| goto force; |
| |
| /* Avoid endless loop for tasks bypassed by the oom killer */ |
| if (passed_oom && task_is_dying()) |
| goto nomem; |
| |
| /* |
| * 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. |
| */ |
| oom_status = mem_cgroup_oom(mem_over_limit, gfp_mask, |
| get_order(nr_pages * PAGE_SIZE)); |
| if (oom_status == OOM_SUCCESS) { |
| passed_oom = true; |
| nr_retries = MAX_RECLAIM_RETRIES; |
| goto retry; |
| } |
| nomem: |
| if (!(gfp_mask & __GFP_NOFAIL)) |
| return -ENOMEM; |
| force: |
| /* |
| * 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. |
| */ |
| page_counter_charge(&memcg->memory, nr_pages); |
| if (do_memsw_account()) |
| page_counter_charge(&memcg->memsw, nr_pages); |
| |
| 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 mem_high, swap_high; |
| |
| mem_high = page_counter_read(&memcg->memory) > |
| READ_ONCE(memcg->memory.high); |
| swap_high = page_counter_read(&memcg->swap) > |
| READ_ONCE(memcg->swap.high); |
| |
| /* Don't bother a random interrupted task */ |
| if (in_interrupt()) { |
| if (mem_high) { |
| schedule_work(&memcg->high_work); |
| break; |
| } |
| continue; |
| } |
| |
| 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; |
| } |
| } while ((memcg = parent_mem_cgroup(memcg))); |
| |
| return 0; |
| } |
| |
| #if defined(CONFIG_MEMCG_KMEM) || defined(CONFIG_MMU) |
| static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages) |
| { |
| if (mem_cgroup_is_root(memcg)) |
| return; |
| |
| page_counter_uncharge(&memcg->memory, nr_pages); |
| if (do_memsw_account()) |
| page_counter_uncharge(&memcg->memsw, nr_pages); |
| } |
| #endif |
| |
| static void commit_charge(struct page *page, struct mem_cgroup *memcg) |
| { |
| VM_BUG_ON_PAGE(page->mem_cgroup, page); |
| /* |
| * Any of the following ensures page->mem_cgroup stability: |
| * |
| * - the page lock |
| * - LRU isolation |
| * - lock_page_memcg() |
| * - exclusive reference |
| * - mem_cgroup_trylock_pages() |
| */ |
| page->mem_cgroup = memcg; |
| } |
| |
| #ifdef CONFIG_MEMCG_KMEM |
| /* |
| * The allocated objcg pointers array is not accounted directly. |
| * Moreover, it should not come from DMA buffer and is not readily |
| * reclaimable. So those GFP bits should be masked off. |
| */ |
| #define OBJCGS_CLEAR_MASK (__GFP_DMA | __GFP_RECLAIMABLE | \ |
| __GFP_ACCOUNT | __GFP_NOFAIL) |
| |
| int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s, |
| gfp_t gfp) |
| { |
| unsigned int objects = objs_per_slab_page(s, page); |
| void *vec; |
| |
| gfp &= ~OBJCGS_CLEAR_MASK; |
| vec = kcalloc_node(objects, sizeof(struct obj_cgroup *), gfp, |
| page_to_nid(page)); |
| if (!vec) |
| return -ENOMEM; |
| |
| if (cmpxchg(&page->obj_cgroups, NULL, |
| (struct obj_cgroup **) ((unsigned long)vec | 0x1UL))) |
| kfree(vec); |
| else |
| kmemleak_not_leak(vec); |
| |
| return 0; |
| } |
| |
| /* |
| * Returns a pointer to the memory cgroup to which the kernel object is charged. |
| * |
| * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(), |
| * cgroup_mutex, etc. |
| */ |
| struct mem_cgroup *mem_cgroup_from_obj(void *p) |
| { |
| struct page *page; |
| |
| if (mem_cgroup_disabled()) |
| return NULL; |
| |
| page = virt_to_head_page(p); |
| |
| /* |
| * If page->mem_cgroup is set, it's either a simple mem_cgroup pointer |
| * or a pointer to obj_cgroup vector. In the latter case the lowest |
| * bit of the pointer is set. |
| * The page->mem_cgroup pointer can be asynchronously changed |
| * from NULL to (obj_cgroup_vec | 0x1UL), but can't be changed |
| * from a valid memcg pointer to objcg vector or back. |
| */ |
| if (!page->mem_cgroup) |
| return NULL; |
| |
| /* |
| * Slab objects are accounted individually, not per-page. |
| * Memcg membership data for each individual object is saved in |
| * the page->obj_cgroups. |
| */ |
| if (page_has_obj_cgroups(page)) { |
| struct obj_cgroup *objcg; |
| unsigned int off; |
| |
| off = obj_to_index(page->slab_cache, page, p); |
| objcg = page_obj_cgroups(page)[off]; |
| if (objcg) |
| return obj_cgroup_memcg(objcg); |
| |
| return NULL; |
| } |
| |
| /* All other pages use page->mem_cgroup */ |
| return page->mem_cgroup; |
| } |
| |
| __always_inline struct obj_cgroup *get_obj_cgroup_from_current(void) |
| { |
| struct obj_cgroup *objcg = NULL; |
| struct mem_cgroup *memcg; |
| |
| if (memcg_kmem_bypass()) |
| return NULL; |
| |
| rcu_read_lock(); |
| if (unlikely(active_memcg())) |
| memcg = active_memcg(); |
| else |
| memcg = mem_cgroup_from_task(current); |
| |
| for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) { |
| objcg = rcu_dereference(memcg->objcg); |
| if (objcg && obj_cgroup_tryget(objcg)) |
| break; |
| objcg = NULL; |
| } |
| rcu_read_unlock(); |
| |
| return objcg; |
| } |
| |
| static int memcg_alloc_cache_id(void) |
| { |
| int id, size; |
| int err; |
| |
| id = ida_simple_get(&memcg_cache_ida, |
| 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL); |
| if (id < 0) |
| return id; |
| |
| if (id < memcg_nr_cache_ids) |
| return id; |
| |
| /* |
| * There's no space for the new id in memcg_caches arrays, |
| * so we have to grow them. |
| */ |
| down_write(&memcg_cache_ids_sem); |
| |
| size = 2 * (id + 1); |
| if (size < MEMCG_CACHES_MIN_SIZE) |
| size = MEMCG_CACHES_MIN_SIZE; |
| else if (size > MEMCG_CACHES_MAX_SIZE) |
| size = MEMCG_CACHES_MAX_SIZE; |
| |
| err = memcg_update_all_list_lrus(size); |
| if (!err) |
| memcg_nr_cache_ids = size; |
| |
| up_write(&memcg_cache_ids_sem); |
| |
| if (err) { |
| ida_simple_remove(&memcg_cache_ida, id); |
| return err; |
| } |
| return id; |
| } |
| |
| static void memcg_free_cache_id(int id) |
| { |
| ida_simple_remove(&memcg_cache_ida, id); |
| } |
| |
| /** |
| * __memcg_kmem_charge: charge a number of kernel pages to a memcg |
| * @memcg: memory cgroup to charge |
| * @gfp: reclaim mode |
| * @nr_pages: number of pages to charge |
| * |
| * Returns 0 on success, an error code on failure. |
| */ |
| int __memcg_kmem_charge(struct mem_cgroup *memcg, gfp_t gfp, |
| unsigned int nr_pages) |
| { |
| struct page_counter *counter; |
| int ret; |
| |
| ret = try_charge(memcg, gfp, nr_pages); |
| if (ret) |
| return ret; |
| |
| if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && |
| !page_counter_try_charge(&memcg->kmem, nr_pages, &counter)) { |
| |
| /* |
| * Enforce __GFP_NOFAIL allocation because callers are not |
| * prepared to see failures and likely do not have any failure |
| * handling code. |
| */ |
| if (gfp & __GFP_NOFAIL) { |
| page_counter_charge(&memcg->kmem, nr_pages); |
| return 0; |
| } |
| cancel_charge(memcg, nr_pages); |
| return -ENOMEM; |
| } |
| return 0; |
| } |
| |
| /** |
| * __memcg_kmem_uncharge: uncharge a number of kernel pages from a memcg |
| * @memcg: memcg to uncharge |
| * @nr_pages: number of pages to uncharge |
| */ |
| void __memcg_kmem_uncharge(struct mem_cgroup *memcg, unsigned int nr_pages) |
| { |
| if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) |
| page_counter_uncharge(&memcg->kmem, nr_pages); |
| |
| refill_stock(memcg, nr_pages); |
| } |
| |
| /** |
| * __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. |
| */ |
| int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order) |
| { |
| struct mem_cgroup *memcg; |
| int ret = 0; |
| |
| memcg = get_mem_cgroup_from_current(); |
| if (memcg && !mem_cgroup_is_root(memcg)) { |
| ret = __memcg_kmem_charge(memcg, gfp, 1 << order); |
| if (!ret) { |
| page->mem_cgroup = memcg; |
| __SetPageKmemcg(page); |
| return 0; |
| } |
| css_put(&memcg->css); |
| } |
| return ret; |
| } |
| |
| /** |
| * __memcg_kmem_uncharge_page: uncharge a kmem page |
| * @page: page to uncharge |
| * @order: allocation order |
| */ |
| void __memcg_kmem_uncharge_page(struct page *page, int order) |
| { |
| struct mem_cgroup *memcg = page->mem_cgroup; |
| unsigned int nr_pages = 1 << order; |
| |
| if (!memcg) |
| return; |
| |
| VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page); |
| __memcg_kmem_uncharge(memcg, nr_pages); |
| page->mem_cgroup = NULL; |
| css_put(&memcg->css); |
| |
| /* slab pages do not have PageKmemcg flag set */ |
| if (PageKmemcg(page)) |
| __ClearPageKmemcg(page); |
| } |
| |
| static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes) |
| { |
| struct memcg_stock_pcp *stock; |
| unsigned long flags; |
| bool ret = false; |
| |
| local_irq_save(flags); |
| |
| stock = this_cpu_ptr(&memcg_stock); |
| if (objcg == stock->cached_objcg && stock->nr_bytes >= nr_bytes) { |
| stock->nr_bytes -= nr_bytes; |
| ret = true; |
| } |
| |
| local_irq_restore(flags); |
| |
| return ret; |
| } |
| |
| static void drain_obj_stock(struct memcg_stock_pcp *stock) |
| { |
| struct obj_cgroup *old = stock->cached_objcg; |
| |
| if (!old) |
| return; |
| |
| if (stock->nr_bytes) { |
| unsigned int nr_pages = stock->nr_bytes >> PAGE_SHIFT; |
| unsigned int nr_bytes = stock->nr_bytes & (PAGE_SIZE - 1); |
| |
| if (nr_pages) { |
| struct mem_cgroup *memcg; |
| |
| rcu_read_lock(); |
| retry: |
| memcg = obj_cgroup_memcg(old); |
| if (unlikely(!css_tryget(&memcg->css))) |
| goto retry; |
| rcu_read_unlock(); |
| |
| __memcg_kmem_uncharge(memcg, nr_pages); |
| 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; |
| } |
| |
| obj_cgroup_put(old); |
| stock->cached_objcg = NULL; |
| } |
| |
| static bool obj_stock_flush_required(struct memcg_stock_pcp *stock, |
| struct mem_cgroup *root_memcg) |
| { |
| struct mem_cgroup *memcg; |
| |
| if (stock->cached_objcg) { |
| memcg = obj_cgroup_memcg(stock->cached_objcg); |
| if (memcg && mem_cgroup_is_descendant(memcg, root_memcg)) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes) |
| { |
| struct memcg_stock_pcp *stock; |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| |
| stock = this_cpu_ptr(&memcg_stock); |
| if (stock->cached_objcg != objcg) { /* reset if necessary */ |
| drain_obj_stock(stock); |
| obj_cgroup_get(objcg); |
| stock->cached_objcg = objcg; |
| stock->nr_bytes = atomic_xchg(&objcg->nr_charged_bytes, 0); |
| } |
| stock->nr_bytes += nr_bytes; |
| |
| if (stock->nr_bytes > PAGE_SIZE) |
| drain_obj_stock(stock); |
| |
| local_irq_restore(flags); |
| } |
| |
| int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size) |
| { |
| struct mem_cgroup *memcg; |
| unsigned int nr_pages, nr_bytes; |
| int ret; |
| |
| if (consume_obj_stock(objcg, size)) |
| return 0; |
| |
| /* |
| * In theory, memcg->nr_charged_bytes can have enough |
| * pre-charged bytes to satisfy the allocation. However, |
| * flushing memcg->nr_charged_bytes requires two atomic |
| * operations, and memcg->nr_charged_bytes can't be big, |
| * so it's better to ignore it and try grab some new pages. |
| * memcg->nr_charged_bytes will be flushed in |
| * refill_obj_stock(), called from this function or |
| * independently later. |
| */ |
| rcu_read_lock(); |
| retry: |
| memcg = obj_cgroup_memcg(objcg); |
| if (unlikely(!css_tryget(&memcg->css))) |
| goto retry; |
| rcu_read_unlock(); |
| |
| nr_pages = size >> PAGE_SHIFT; |
| nr_bytes = size & (PAGE_SIZE - 1); |
| |
| if (nr_bytes) |
| nr_pages += 1; |
| |
| ret = __memcg_kmem_charge(memcg, gfp, nr_pages); |
| if (!ret && nr_bytes) |
| refill_obj_stock(objcg, PAGE_SIZE - nr_bytes); |
| |
| css_put(&memcg->css); |
| return ret; |
| } |
| |
| void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size) |
| { |
| refill_obj_stock(objcg, size); |
| } |
| |
| #endif /* CONFIG_MEMCG_KMEM */ |
| |
| /* |
| * Because head->mem_cgroup is not set on tails, set it now. |
| */ |
| void split_page_memcg(struct page *head, unsigned int nr) |
| { |
| struct mem_cgroup *memcg = head->mem_cgroup; |
| int kmemcg = PageKmemcg(head); |
| int i; |
| |
| if (mem_cgroup_disabled() || !memcg) |
| return; |
| |
| for (i = 1; i < nr; i++) { |
| head[i].mem_cgroup = memcg; |
| if (kmemcg) |
| __SetPageKmemcg(head + i); |
| } |
| css_get_many(&memcg->css, nr - 1); |
| } |
| |
| #ifdef CONFIG_MEMCG_SWAP |
| /** |
| * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record. |
| * @entry: swap entry to be moved |
| * @from: mem_cgroup which the entry is moved from |
| * @to: mem_cgroup which the entry is moved to |
| * |
| * It succeeds only when the swap_cgroup's record for this entry is the same |
| * as the mem_cgroup's id of @from. |
| * |
| * Returns 0 on success, -EINVAL on failure. |
| * |
| * The caller must have charged to @to, IOW, called page_counter_charge() about |
| * both res and memsw, and called css_get(). |
| */ |
| static int mem_cgroup_move_swap_account(swp_entry_t entry, |
| struct mem_cgroup *from, struct mem_cgroup *to) |
| { |
| unsigned short old_id, new_id; |
| |
| old_id = mem_cgroup_id(from); |
| new_id = mem_cgroup_id(to); |
| |
| if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { |
| mod_memcg_state(from, MEMCG_SWAP, -1); |
| mod_memcg_state(to, MEMCG_SWAP, 1); |
| return 0; |
| } |
| return -EINVAL; |
| } |
| #else |
| static inline int mem_cgroup_move_swap_account(swp_entry_t entry, |
| struct mem_cgroup *from, struct mem_cgroup *to) |
| { |
| return -EINVAL; |
| } |
| #endif |
| |
| static DEFINE_MUTEX(memcg_max_mutex); |
| |
| static int mem_cgroup_resize_max(struct mem_cgroup *memcg, |
| unsigned long max, bool memsw) |
| { |
| bool enlarge = false; |
| bool drained = false; |
| int ret; |
| bool limits_invariant; |
| struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory; |
| |
| do { |
| if (signal_pending(current)) { |
| ret = -EINTR; |
| break; |
| } |
| |
| mutex_lock(&memcg_max_mutex); |
| /* |
|