| // 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 |
| * |
| * Per memcg lru locking |
| * Copyright (C) 2020 Alibaba, Inc, Alex Shi |
| */ |
| |
| #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> |
| |
| 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 should_force_charge(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 |
| extern spinlock_t css_set_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(&css_set_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(&css_set_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(&css_set_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(&css_set_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_memcg(page); |
| |
| 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_memcg_check(page); |
| |
| 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; |
| } else { |
| 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_page_state(struct page *page, enum node_stat_item idx, |
| int val) |
| { |
| struct page *head = compound_head(page); /* rmap on tail pages */ |
| struct mem_cgroup *memcg = page_memcg(head); |
| pg_data_t *pgdat = page_pgdat(page); |
| struct lruvec *lruvec; |
| |
| /* Untracked pages have no memcg, no lruvec. Update only the node */ |
| if (!memcg) { |
| __mod_node_page_state(pgdat, idx, val); |
| return; |
| } |
| |
| lruvec = mem_cgroup_lruvec(memcg, pgdat); |
| __mod_lruvec_state(lruvec, idx, val); |
| } |
| EXPORT_SYMBOL(__mod_lruvec_page_state); |
| |
| void __mod_lruvec_kmem_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(); |
| } |
| |
| /** |
| * __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_memcg(page); |
| |
| 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(); |
| if (memcg) { |
| /* current->active_memcg must hold a ref. */ |
| if (WARN_ON_ONCE(!css_tryget(&memcg->css))) |
| memcg = root_mem_cgroup; |
| else |
| memcg = current->active_memcg; |
| } |
| 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; |
| |
| 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(); |
| 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; |
| } |
| |
| #ifdef CONFIG_DEBUG_VM |
| void lruvec_memcg_debug(struct lruvec *lruvec, struct page *page) |
| { |
| struct mem_cgroup *memcg; |
| |
| if (mem_cgroup_disabled()) |
| return; |
| |
| memcg = page_memcg(page); |
| |
| if (!memcg) |
| VM_BUG_ON_PAGE(lruvec_memcg(lruvec) != root_mem_cgroup, page); |
| else |
| VM_BUG_ON_PAGE(lruvec_memcg(lruvec) != memcg, page); |
| } |
| #endif |
| |
| /** |
| * lock_page_lruvec - lock and return lruvec for a given page. |
| * @page: the page |
| * |
| * This series functions should be used in either conditions: |
| * PageLRU is cleared or unset |
| * or page->_refcount is zero |
| * or page is locked. |
| */ |
| struct lruvec *lock_page_lruvec(struct page *page) |
| { |
| struct lruvec *lruvec; |
| struct pglist_data *pgdat = page_pgdat(page); |
| |
| rcu_read_lock(); |
| lruvec = mem_cgroup_page_lruvec(page, pgdat); |
| spin_lock(&lruvec->lru_lock); |
| rcu_read_unlock(); |
| |
| lruvec_memcg_debug(lruvec, page); |
| |
| return lruvec; |
| } |
| |
| struct lruvec *lock_page_lruvec_irq(struct page *page) |
| { |
| struct lruvec *lruvec; |
| struct pglist_data *pgdat = page_pgdat(page); |
| |
| rcu_read_lock(); |
| lruvec = mem_cgroup_page_lruvec(page, pgdat); |
| spin_lock_irq(&lruvec->lru_lock); |
| rcu_read_unlock(); |
| |
| lruvec_memcg_debug(lruvec, page); |
| |
| return lruvec; |
| } |
| |
| struct lruvec *lock_page_lruvec_irqsave(struct page *page, unsigned long *flags) |
| { |
| struct lruvec *lruvec; |
| struct pglist_data *pgdat = page_pgdat(page); |
| |
| rcu_read_lock(); |
| lruvec = mem_cgroup_page_lruvec(page, pgdat); |
| spin_lock_irqsave(&lruvec->lru_lock, *flags); |
| rcu_read_unlock(); |
| |
| lruvec_memcg_debug(lruvec, page); |
| |
| 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 }, |
| { "pagetables", PAGE_SIZE, NR_PAGETABLE }, |
| { "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 }, |
| { "file_thp", 0, NR_FILE_THPS }, |
| { "shmem_thp", 0, NR_SHMEM_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].idx == NR_FILE_THPS || |
| memory_stats[i].idx == NR_SHMEM_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 = should_force_charge() || 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 and memcg 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 = page_memcg(head); |
| if (unlikely(!memcg)) |
| return NULL; |
| |
| #ifdef CONFIG_PROVE_LOCKING |
| local_irq_save(flags); |
| might_lock(&memcg->move_lock); |
| local_irq_restore(flags); |
| #endif |
| |
| if (atomic_read(&memcg->moving_account) <= 0) |
| return memcg; |
| |
| spin_lock_irqsave(&memcg->move_lock, flags); |
| if (memcg != page_memcg(head)) { |
| 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 and memcg binding |
| * @page: the page |
| */ |
| void unlock_page_memcg(struct page *page) |
| { |
| struct page *head = compound_head(page); |
| |
| __unlock_page_memcg(page_memcg(head)); |
| } |
| 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 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; |
| |
| /* |
| * Unlike in global OOM situations, memcg is not in a physical |
| * memory shortage. Allow dying and OOM-killed tasks to |
| * bypass the last charges so that they can exit quickly and |
| * free their memory. |
| */ |
| if (unlikely(should_force_charge())) |
| 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; |
| |
| if (fatal_signal_pending(current)) |
| goto force; |
| |
| /* |
| * 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)); |
| switch (oom_status) { |
| case OOM_SUCCESS: |
| nr_retries = MAX_RECLAIM_RETRIES; |
| goto retry; |
| case OOM_FAILED: |
| goto force; |
| default: |
| goto nomem; |
| } |
| 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_memcg(page), page); |
| /* |
| * Any of the following ensures page's memcg stability: |
| * |
| * - the page lock |
| * - LRU isolation |
| * - lock_page_memcg() |
| * - exclusive reference |
| */ |
| page->memcg_data = (unsigned long)memcg; |
| } |
| |
| #ifdef CONFIG_MEMCG_KMEM |
| 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; |
| |
| vec = kcalloc_node(objects, sizeof(struct obj_cgroup *), gfp, |
| page_to_nid(page)); |
| if (!vec) |
| return -ENOMEM; |
| |
| if (!set_page_objcgs(page, vec)) |
| kfree(vec); |
| else |
| kmemleak_not_leak(vec); |
| |
| return 0; |
| } |
| |
| /* |
| * Returns a pointer to the memory cgroup to which the kernel object is charged. |
| * |
| * A passed kernel object can be a slab object or a generic kernel page, so |
| * different mechanisms for getting the memory cgroup pointer should be used. |
| * In certain cases (e.g. kernel stacks or large kmallocs with SLUB) the caller |
| * can not know for sure how the kernel object is implemented. |
| * mem_cgroup_from_obj() can be safely used in such cases. |
| * |
| * 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); |
| |
| /* |
| * Slab objects are accounted individually, not per-page. |
| * Memcg membership data for each individual object is saved in |
| * the page->obj_cgroups. |
| */ |
| if (page_objcgs_check(page)) { |
| struct obj_cgroup *objcg; |
| unsigned int off; |
| |
| off = obj_to_index(page->slab_cache, page, p); |
| objcg = page_objcgs(page)[off]; |
| if (objcg) |
| return obj_cgroup_memcg(objcg); |
| |
| return NULL; |
| } |
| |
| /* |
| * page_memcg_check() is used here, because page_has_obj_cgroups() |
| * check above could fail because the object cgroups vector wasn't set |
| * at that moment, but it can be set concurrently. |
| * page_memcg_check(page) will guarantee that a proper memory |
| * cgroup pointer or NULL will be returned. |
| */ |
| return page_memcg_check(page); |
| } |
| |
| __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); |
| |
| page_counter_uncharge(&memcg->memory, nr_pages); |
| if (do_memsw_account()) |
| page_counter_uncharge(&memcg->memsw, 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->memcg_data = (unsigned long)memcg | |
| MEMCG_DATA_KMEM; |
| 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_memcg(page); |
| 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->memcg_data = 0; |
| css_put(&memcg->css); |
| } |
| |
| 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) { |
| rcu_read_lock(); |
| __memcg_kmem_uncharge(obj_cgroup_memcg(old), nr_pages); |
| rcu_read_unlock(); |
| } |
| |
| /* |
| * 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 */ |
| |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| /* |
| * Because page_memcg(head) is not set on compound tails, set it now. |
| */ |
| void mem_cgroup_split_huge_fixup(struct page *head) |
| { |
| struct mem_cgroup *memcg = page_memcg(head); |
| int i; |
| |
| if (mem_cgroup_disabled()) |
| return; |
| |
| for (i = 1; i < HPAGE_PMD_NR; i++) { |
| css_get(&memcg->css); |
| head[i].memcg_data = (unsigned long)memcg; |
| } |
| } |
| #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ |
| |
| #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); |
| /* |
| * Make sure that the new limit (memsw or memory limit) doesn't |
| * break our basic invariant rule memory.max <= memsw.max. |
| */ |
| limits_invariant = memsw ? max >= READ_ONCE(memcg->memory.max) : |
| max <= memcg->memsw.max; |
| if (!limits_invariant) { |
| mutex_unlock(&memcg_max_mutex); |
| ret = -EINVAL; |
| break; |
| } |
| if (max > counter->max) |
| enlarge = true; |
| ret = page_counter_set_max(counter, max); |
| mutex_unlock(&memcg_max_mutex); |
| |
| if (!ret) |
| break; |
| |
| if (!drained) { |
| drain_all_stock(memcg); |
| drained = true; |
| continue; |
| } |
| |
| if (!try_to_free_mem_cgroup_pages(memcg, 1, |
| GFP_KERNEL, !memsw)) { |
| ret = -EBUSY; |
| break; |
| } |
| } while (true); |
| |
| if (!ret && enlarge) |
| memcg_oom_recover(memcg); |
| |
| return ret; |
| } |
| |
| unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, |
| gfp_t gfp_mask, |
| unsigned long *total_scanned) |
| { |
| unsigned long nr_reclaimed = 0; |
| struct mem_cgroup_per_node *mz, *next_mz = NULL; |
| unsigned long reclaimed; |
| int loop = 0; |
| struct mem_cgroup_tree_per_node *mctz; |
| unsigned long excess; |
| unsigned long nr_scanned; |
| |
| if (order > 0) |
| return 0; |
| |
| mctz = soft_limit_tree_node(pgdat->node_id); |
| |
| /* |
| * Do not even bother to check the largest node if the root |
| * is empty. Do it lockless to prevent lock bouncing. Races |
| * are acceptable as soft limit is best effort anyway. |
| */ |
| if (!mctz || RB_EMPTY_ROOT(&mctz->rb_root)) |
| return 0; |
| |
| /* |
| * This loop can run a while, specially if mem_cgroup's continuously |
| * keep exceeding their soft limit and putting the system under |
| * pressure |
| */ |
| do { |
| if (next_mz) |
| mz = next_mz; |
| else |
| mz = mem_cgroup_largest_soft_limit_node(mctz); |
| if (!mz) |
| break; |
| |
| nr_scanned = 0; |
| reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat, |
| gfp_mask, &nr_scanned); |
| nr_reclaimed += reclaimed; |
| *total_scanned += nr_scanned; |
| spin_lock_irq(&mctz->lock); |
| __mem_cgroup_remove_exceeded(mz, mctz); |
| |
| /* |
| * If we failed to reclaim anything from this memory cgroup |
| * it is time to move on to the next cgroup |
| */ |
| next_mz = NULL; |
| if (!reclaimed) |
| next_mz = __mem_cgroup_largest_soft_limit_node(mctz); |
| |
| excess = soft_limit_excess(mz->memcg); |
| /* |
| * One school of thought says that we should not add |
| * back the node to the tree if reclaim returns 0. |
| * But our reclaim could return 0, simply because due |
| * to priority we are exposing a smaller subset of |
| * memory to reclaim from. Consider this as a longer |
| * term TODO. |
| */ |
| /* If excess == 0, no tree ops */ |
| __mem_cgroup_insert_exceeded(mz, mctz, excess); |
| spin_unlock_irq(&mctz->lock); |
| css_put(&mz->memcg->css); |
| loop++; |
| /* |
| * Could not reclaim anything and there are no more |
| * mem cgroups to try or we seem to be looping without |
| * reclaiming anything. |
| */ |
| if (!nr_reclaimed && |
| (next_mz == NULL || |
| loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS)) |
| break; |
| } while (!nr_reclaimed); |
| if (next_mz) |
| css_put(&next_mz->memcg->css); |
| return nr_reclaimed; |
| } |
| |
| /* |
| * Reclaims as many pages from the given memcg as possible. |
| * |
| * Caller is responsible for holding css reference for memcg. |
| */ |
| static int mem_cgroup_force_empty(struct mem_cgroup *memcg) |
| { |
| int nr_retries = MAX_RECLAIM_RETRIES; |
| |
| /* we call try-to-free pages for make this cgroup empty */ |
| lru_add_drain_all(); |
| |
| drain_all_stock(memcg); |
| |
| /* try to free all pages in this cgroup */ |
| while (nr_retries && page_counter_read(&memcg->memory)) { |
| int progress; |
| |
| if (signal_pending(current)) |
| return -EINTR; |
| |
| progress = try_to_free_mem_cgroup_pages(memcg, 1, |
| GFP_KERNEL, true); |
| if (!progress) { |
| nr_retries--; |
| /* maybe some writeback is necessary */ |
| congestion_wait(BLK_RW_ASYNC, HZ/10); |
| } |
| |
| } |
| |
| return 0; |
| } |
| |
| static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of, |
| char *buf, size_t nbytes, |
| loff_t off) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); |
| |
| if (mem_cgroup_is_root(memcg)) |
| return -EINVAL; |
| return mem_cgroup_force_empty(memcg) ?: nbytes; |
| } |
| |
| static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css, |
| struct cftype *cft) |
| { |
| return 1; |
| } |
| |
| static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css, |
| struct cftype *cft, u64 val) |
| { |
| if (val == 1) |
| return 0; |
| |
| pr_warn_once("Non-hierarchical mode is deprecated. " |
| "Please report your usecase to linux-mm@kvack.org if you " |
| "depend on this functionality.\n"); |
| |
| return -EINVAL; |
| } |
| |
| static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) |
| { |
| unsigned long val; |
| |
| if (mem_cgroup_is_root(memcg)) { |
| val = memcg_page_state(memcg, NR_FILE_PAGES) + |
| memcg_page_state(memcg, NR_ANON_MAPPED); |
| if (swap) |
| val += memcg_page_state(memcg, MEMCG_SWAP); |
| } else { |
| if (!swap) |
| val = page_counter_read(&memcg->memory); |
| else |
| val = page_counter_read(&memcg->memsw); |
| } |
| return val; |
| } |
| |
| enum { |
| RES_USAGE, |
| RES_LIMIT, |
| RES_MAX_USAGE, |
| RES_FAILCNT, |
| RES_SOFT_LIMIT, |
| }; |
| |
| static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css, |
| struct cftype *cft) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
| struct page_counter *counter; |
| |
| switch (MEMFILE_TYPE(cft->private)) { |
| case _MEM: |
| counter = &memcg->memory; |
| break; |
| case _MEMSWAP: |
| counter = &memcg->memsw; |
| break; |
| case _KMEM: |
| counter = &memcg->kmem; |
| break; |
| case _TCP: |
| counter = &memcg->tcpmem; |
| break; |
| default: |
| BUG(); |
| } |
| |
| switch (MEMFILE_ATTR(cft->private)) { |
| case RES_USAGE: |
| if (counter == &memcg->memory) |
| return (u64)mem_cgroup_usage(memcg, false) * PAGE_SIZE; |
| if (counter == &memcg->memsw) |
| return (u64)mem_cgroup_usage(memcg, true) * PAGE_SIZE; |
| return (u64)page_counter_read(counter) * PAGE_SIZE; |
| case RES_LIMIT: |
| return (u64)counter->max * PAGE_SIZE; |
| case RES_MAX_USAGE: |
| return (u64)counter->watermark * PAGE_SIZE; |
| case RES_FAILCNT: |
| return counter->failcnt; |
| case RES_SOFT_LIMIT: |
| return (u64)memcg->soft_limit * PAGE_SIZE; |
| default: |
| BUG(); |
| } |
| } |
| |
| static void memcg_flush_percpu_vmstats(struct mem_cgroup *memcg) |
| { |
| unsigned long stat[MEMCG_NR_STAT] = {0}; |
| struct mem_cgroup *mi; |
| int node, cpu, i; |
| |
| for_each_online_cpu(cpu) |
| for (i = 0; i < MEMCG_NR_STAT; i++) |
| stat[i] += per_cpu(memcg->vmstats_percpu->stat[i], cpu); |
| |
| for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) |
| for (i = 0; i < MEMCG_NR_STAT; i++) |
| atomic_long_add(stat[i], &mi->vmstats[i]); |
| |
| for_each_node(node) { |
| struct mem_cgroup_per_node *pn = memcg->nodeinfo[node]; |
| struct mem_cgroup_per_node *pi; |
| |
| for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) |
| stat[i] = 0; |
| |
| for_each_online_cpu(cpu) |
| for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) |
| stat[i] += per_cpu( |
| pn->lruvec_stat_cpu->count[i], cpu); |
| |
| for (pi = pn; pi; pi = parent_nodeinfo(pi, node)) |
| for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) |
| atomic_long_add(stat[i], &pi->lruvec_stat[i]); |
| } |
| } |
| |
| static void memcg_flush_percpu_vmevents(struct mem_cgroup *memcg) |
| { |
| unsigned long events[NR_VM_EVENT_ITEMS]; |
| struct mem_cgroup *mi; |
| int cpu, i; |
| |
| for (i = 0; i < NR_VM_EVENT_ITEMS; i++) |
| events[i] = 0; |
| |
| for_each_online_cpu(cpu) |
| for (i = 0; i < NR_VM_EVENT_ITEMS; i++) |
| events[i] += per_cpu(memcg->vmstats_percpu->events[i], |
| cpu); |
| |
| for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) |
| for (i = 0; i < NR_VM_EVENT_ITEMS; i++) |
| atomic_long_add(events[i], &mi->vmevents[i]); |
| } |
| |
| #ifdef CONFIG_MEMCG_KMEM |
| static int memcg_online_kmem(struct mem_cgroup *memcg) |
| { |
| struct obj_cgroup *objcg; |
| int memcg_id; |
| |
| if (cgroup_memory_nokmem) |
| return 0; |
| |
| BUG_ON(memcg->kmemcg_id >= 0); |
| BUG_ON(memcg->kmem_state); |
| |
| memcg_id = memcg_alloc_cache_id(); |
| if (memcg_id < 0) |
| return memcg_id; |
| |
| objcg = obj_cgroup_alloc(); |
| if (!objcg) { |
| memcg_free_cache_id(memcg_id); |
| return -ENOMEM; |
| } |
| objcg->memcg = memcg; |
| rcu_assign_pointer(memcg->objcg, objcg); |
| |
| static_branch_enable(&memcg_kmem_enabled_key); |
| |
| memcg->kmemcg_id = memcg_id; |
| memcg->kmem_state = KMEM_ONLINE; |
| |
| return 0; |
| } |
| |
| static void memcg_offline_kmem(struct mem_cgroup *memcg) |
| { |
| struct cgroup_subsys_state *css; |
| struct mem_cgroup *parent, *child; |
| int kmemcg_id; |
| |
| if (memcg->kmem_state != KMEM_ONLINE) |
| return; |
| |
| memcg->kmem_state = KMEM_ALLOCATED; |
| |
| parent = parent_mem_cgroup(memcg); |
| if (!parent) |
| parent = root_mem_cgroup; |
| |
| memcg_reparent_objcgs(memcg, parent); |
| |
| kmemcg_id = memcg->kmemcg_id; |
| BUG_ON(kmemcg_id < 0); |
| |
| /* |
| * Change kmemcg_id of this cgroup and all its descendants to the |
| * parent's id, and then move all entries from this cgroup's list_lrus |
| * to ones of the parent. After we have finished, all list_lrus |
| * corresponding to this cgroup are guaranteed to remain empty. The |
| * ordering is imposed by list_lru_node->lock taken by |
| * memcg_drain_all_list_lrus(). |
| */ |
| rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */ |
| css_for_each_descendant_pre(css, &memcg->css) { |
| child = mem_cgroup_from_css(css); |
| BUG_ON(child->kmemcg_id != kmemcg_id); |
| child->kmemcg_id = parent->kmemcg_id; |
| } |
| rcu_read_unlock(); |
| |
| memcg_drain_all_list_lrus(kmemcg_id, parent); |
| |
| memcg_free_cache_id(kmemcg_id); |
| } |
| |
| static void memcg_free_kmem(struct mem_cgroup *memcg) |
| { |
| /* css_alloc() failed, offlining didn't happen */ |
| if (unlikely(memcg->kmem_state == KMEM_ONLINE)) |
| memcg_offline_kmem(memcg); |
| } |
| #else |
| static int memcg_online_kmem(struct mem_cgroup *memcg) |
| { |
| return 0; |
| } |
| static void memcg_offline_kmem(struct mem_cgroup *memcg) |
| { |
| } |
| static void memcg_free_kmem(struct mem_cgroup *memcg) |
| { |
| } |
| #endif /* CONFIG_MEMCG_KMEM */ |
| |
| static int memcg_update_kmem_max(struct mem_cgroup *memcg, |
| unsigned long max) |
| { |
| int ret; |
| |
| mutex_lock(&memcg_max_mutex); |
| ret = page_counter_set_max(&memcg->kmem, max); |
| mutex_unlock(&memcg_max_mutex); |
| return ret; |
| } |
| |
| static int memcg_update_tcp_max(struct mem_cgroup *memcg, unsigned long max) |
| { |
| int ret; |
| |
| mutex_lock(&memcg_max_mutex); |
| |
| ret = page_counter_set_max(&memcg->tcpmem, max); |
| if (ret) |
| goto out; |
| |
| if (!memcg->tcpmem_active) { |
| /* |
| * The active flag needs to be written after the static_key |
| * update. This is what guarantees that the socket activation |
| * function is the last one to run. See mem_cgroup_sk_alloc() |
| * for details, and note that we don't mark any socket as |
| * belonging to this memcg until that flag is up. |
| * |
| * We need to do this, because static_keys will span multiple |
| * sites, but we can't control their order. If we mark a socket |
| * as accounted, but the accounting functions are not patched in |
| * yet, we'll lose accounting. |
| * |
| * We never race with the readers in mem_cgroup_sk_alloc(), |
| * because when this value change, the code to process it is not |
| * patched in yet. |
| */ |
| static_branch_inc(&memcg_sockets_enabled_key); |
| memcg->tcpmem_active = true; |
| } |
| out: |
| mutex_unlock(&memcg_max_mutex); |
| return ret; |
| } |
| |
| /* |
| * The user of this function is... |
| * RES_LIMIT. |
| */ |
| static ssize_t mem_cgroup_write(struct kernfs_open_file *of, |
| char *buf, size_t nbytes, loff_t off) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); |
| unsigned long nr_pages; |
| int ret; |
| |
| buf = strstrip(buf); |
| ret = page_counter_memparse(buf, "-1", &nr_pages); |
| if (ret) |
| return ret; |
| |
| switch (MEMFILE_ATTR(of_cft(of)->private)) { |
| case RES_LIMIT: |
| if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */ |
| ret = -EINVAL; |
| break; |
| } |
| switch (MEMFILE_TYPE(of_cft(of)->private)) { |
| case _MEM: |
| ret = mem_cgroup_resize_max(memcg, nr_pages, false); |
| break; |
| case _MEMSWAP: |
| ret = mem_cgroup_resize_max(memcg, nr_pages, true); |
| break; |
| case _KMEM: |
| pr_warn_once("kmem.limit_in_bytes is deprecated and will be removed. " |
| "Please report your usecase to linux-mm@kvack.org if you " |
| "depend on this functionality.\n"); |
| ret = memcg_update_kmem_max(memcg, nr_pages); |
| break; |
| case _TCP: |
| ret = memcg_update_tcp_max(memcg, nr_pages); |
| break; |
| } |
| break; |
| case RES_SOFT_LIMIT: |
| memcg->soft_limit = nr_pages; |
| ret = 0; |
| break; |
| } |
| return ret ?: nbytes; |
| } |
| |
| static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf, |
| size_t nbytes, loff_t off) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); |
| struct page_counter *counter; |
| |
| switch (MEMFILE_TYPE(of_cft(of)->private)) { |
| case _MEM: |
| counter = &memcg->memory; |
| break; |
| case _MEMSWAP: |
| counter = &memcg->memsw; |
| break; |
| case _KMEM: |
| counter = &memcg->kmem; |
| break; |
| case _TCP: |
| counter = &memcg->tcpmem; |
| break; |
| default: |
| BUG(); |
| } |
| |
| switch (MEMFILE_ATTR(of_cft(of)->private)) { |
| case RES_MAX_USAGE: |
| page_counter_reset_watermark(counter); |
| break; |
| case RES_FAILCNT: |
| counter->failcnt = 0; |
| break; |
| default: |
| BUG(); |
| } |
| |
| return nbytes; |
| } |
| |
| static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css, |
| struct cftype *cft) |
| { |
| return mem_cgroup_from_css(css)->move_charge_at_immigrate; |
| } |
| |
| #ifdef CONFIG_MMU |
| static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, |
| struct cftype *cft, u64 val) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
| |
| if (val & ~MOVE_MASK) |
| return -EINVAL; |
| |
| /* |
| * No kind of locking is needed in here, because ->can_attach() will |
| * check this value once in the beginning of the process, and then carry |
| * on with stale data. This means that changes to this value will only |
| * affect task migrations starting after the change. |
| */ |
| memcg->move_charge_at_immigrate = val; |
| return 0; |
| } |
| #else |
| static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, |
| struct cftype *cft, u64 val) |
| { |
| return -ENOSYS; |
| } |
| #endif |
| |
| #ifdef CONFIG_NUMA |
| |
| #define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE)) |
| #define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON)) |
| #define LRU_ALL ((1 << NR_LRU_LISTS) - 1) |
| |
| static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg, |
| int nid, unsigned int lru_mask, bool tree) |
| { |
| struct lruvec *lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid)); |
| unsigned long nr = 0; |
| enum lru_list lru; |
| |
| VM_BUG_ON((unsigned)nid >= nr_node_ids); |
| |
| for_each_lru(lru) { |
| if (!(BIT(lru) & lru_mask)) |
| continue; |
| if (tree) |
| nr += lruvec_page_state(lruvec, NR_LRU_BASE + lru); |
| else |
| nr += lruvec_page_state_local(lruvec, NR_LRU_BASE + lru); |
| } |
| return nr; |
| } |
| |
| static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg, |
| unsigned int lru_mask, |
| bool tree) |
| { |
| unsigned long nr = 0; |
| enum lru_list lru; |
| |
| for_each_lru(lru) { |
| if (!(BIT(lru) & lru_mask)) |
| continue; |
| if (tree) |
| nr += memcg_page_state(memcg, NR_LRU_BASE + lru); |
| else |
| nr += memcg_page_state_local(memcg, NR_LRU_BASE + lru); |
| } |
| return nr; |
| } |
| |
| static int memcg_numa_stat_show(struct seq_file *m, void *v) |
| { |
| struct numa_stat { |
| const char *name; |
| unsigned int lru_mask; |
| }; |
| |
| static const struct numa_stat stats[] = { |
| { "total", LRU_ALL }, |
| { "file", LRU_ALL_FILE }, |
| { "anon", LRU_ALL_ANON }, |
| { "unevictable", BIT(LRU_UNEVICTABLE) }, |
| }; |
| const struct numa_stat *stat; |
| int nid; |
| struct mem_cgroup *memcg = mem_cgroup_from_seq(m); |
| |
| for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { |
| seq_printf(m, "%s=%lu", stat->name, |
| mem_cgroup_nr_lru_pages(memcg, stat->lru_mask, |
| false)); |
| for_each_node_state(nid, N_MEMORY) |
| seq_printf(m, " N%d=%lu", nid, |
| mem_cgroup_node_nr_lru_pages(memcg, nid, |
| stat->lru_mask, false)); |
| seq_putc(m, '\n'); |
| } |
| |
| for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { |
| |
| seq_printf(m, "hierarchical_%s=%lu", stat->name, |
| mem_cgroup_nr_lru_pages(memcg, stat->lru_mask, |
| true)); |
| for_each_node_state(nid, N_MEMORY) |
| seq_printf(m, " N%d=%lu", nid, |
| mem_cgroup_node_nr_lru_pages(memcg, nid, |
| stat->lru_mask, true)); |
| seq_putc(m, '\n'); |
| } |
| |
| return 0; |
| } |
| #endif /* CONFIG_NUMA */ |
| |
| static const unsigned int memcg1_stats[] = { |
| NR_FILE_PAGES, |
| NR_ANON_MAPPED, |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| NR_ANON_THPS, |
| #endif |
| NR_SHMEM, |
| NR_FILE_MAPPED, |
| NR_FILE_DIRTY, |
| NR_WRITEBACK, |
| MEMCG_SWAP, |
| }; |
| |
| static const char *const memcg1_stat_names[] = { |
| "cache", |
| "rss", |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| "rss_huge", |
| #endif |
| "shmem", |
| "mapped_file", |
| "dirty", |
| "writeback", |
| "swap", |
| }; |
| |
| /* Universal VM events cgroup1 shows, original sort order */ |
| static const unsigned int memcg1_events[] = { |
| PGPGIN, |
| PGPGOUT, |
| PGFAULT, |
| PGMAJFAULT, |
| }; |
| |
| static int memcg_stat_show(struct seq_file *m, void *v) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_seq(m); |
| unsigned long memory, memsw; |
| struct mem_cgroup *mi; |
| unsigned int i; |
| |
| BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats)); |
| |
| for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) { |
| unsigned long nr; |
| |
| if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account()) |
| continue; |
| nr = memcg_page_state_local(memcg, memcg1_stats[i]); |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| if (memcg1_stats[i] == NR_ANON_THPS) |
| nr *= HPAGE_PMD_NR; |
| #endif |
| seq_printf(m, "%s %lu\n", memcg1_stat_names[i], nr * PAGE_SIZE); |
| } |
| |
| for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) |
| seq_printf(m, "%s %lu\n", vm_event_name(memcg1_events[i]), |
| memcg_events_local(memcg, memcg1_events[i])); |
| |
| for (i = 0; i < NR_LRU_LISTS; i++) |
| seq_printf(m, "%s %lu\n", lru_list_name(i), |
| memcg_page_state_local(memcg, NR_LRU_BASE + i) * |
| PAGE_SIZE); |
| |
| /* Hierarchical information */ |
| memory = memsw = PAGE_COUNTER_MAX; |
| for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) { |
| memory = min(memory, READ_ONCE(mi->memory.max)); |
| memsw = min(memsw, READ_ONCE(mi->memsw.max)); |
| } |
| seq_printf(m, "hierarchical_memory_limit %llu\n", |
| (u64)memory * PAGE_SIZE); |
| if (do_memsw_account()) |
| seq_printf(m, "hierarchical_memsw_limit %llu\n", |
| (u64)memsw * PAGE_SIZE); |
| |
| for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) { |
| unsigned long nr; |
| |
| if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account()) |
| continue; |
| nr = memcg_page_state(memcg, memcg1_stats[i]); |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| if (memcg1_stats[i] == NR_ANON_THPS) |
| nr *= HPAGE_PMD_NR; |
| #endif |
| seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i], |
| (u64)nr * PAGE_SIZE); |
| } |
| |
| for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) |
| seq_printf(m, "total_%s %llu\n", |
| vm_event_name(memcg1_events[i]), |
| (u64)memcg_events(memcg, memcg1_events[i])); |
| |
| for (i = 0; i < NR_LRU_LISTS; i++) |
| seq_printf(m, "total_%s %llu\n", lru_list_name(i), |
| (u64)memcg_page_state(memcg, NR_LRU_BASE + i) * |
| PAGE_SIZE); |
| |
| #ifdef CONFIG_DEBUG_VM |
| { |
| pg_data_t *pgdat; |
| struct mem_cgroup_per_node *mz; |
| unsigned long anon_cost = 0; |
| unsigned long file_cost = 0; |
| |
| for_each_online_pgdat(pgdat) { |
| mz = mem_cgroup_nodeinfo(memcg, pgdat->node_id); |
| |
| anon_cost += mz->lruvec.anon_cost; |
| file_cost += mz->lruvec.file_cost; |
| } |
| seq_printf(m, "anon_cost %lu\n", anon_cost); |
| seq_printf(m, "file_cost %lu\n", file_cost); |
| } |
| #endif |
| |
| return 0; |
| } |
| |
| static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css, |
| struct cftype *cft) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
| |
| return mem_cgroup_swappiness(memcg); |
| } |
| |
| static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css, |
| struct cftype *cft, u64 val) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
| |
| if (val > 100) |
| return -EINVAL; |
| |
| if (css->parent) |
| memcg->swappiness = val; |
| else |
| vm_swappiness = val; |
| |
| return 0; |
| } |
| |
| static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap) |
| { |
| struct mem_cgroup_threshold_ary *t; |
| unsigned long usage; |
| int i; |
| |
| rcu_read_lock(); |
| if (!swap) |
| t = rcu_dereference(memcg->thresholds.primary); |
| else |
| t = rcu_dereference(memcg->memsw_thresholds.primary); |
| |
| if (!t) |
| goto unlock; |
| |
| usage = mem_cgroup_usage(memcg, swap); |
| |
| /* |
| * current_threshold points to threshold just below or equal to usage. |
| * If it's not true, a threshold was crossed after last |
| * call of __mem_cgroup_threshold(). |
| */ |
| i = t->current_threshold; |
| |
| /* |
| * Iterate backward over array of thresholds starting from |
| * current_threshold and check if a threshold is crossed. |
| * If none of thresholds below usage is crossed, we read |
| * only one element of the array here. |
| */ |
| for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--) |
| eventfd_signal(t->entries[i].eventfd, 1); |
| |
| /* i = current_threshold + 1 */ |
| i++; |
| |
| /* |
| * Iterate forward over array of thresholds starting from |
| * current_threshold+1 and check if a threshold is crossed. |
| * If none of thresholds above usage is crossed, we read |
| * only one element of the array here. |
| */ |
| for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++) |
| eventfd_signal(t->entries[i].eventfd, 1); |
| |
| /* Update current_threshold */ |
| t->current_threshold = i - 1; |
| unlock: |
| rcu_read_unlock(); |
| } |
| |
| static void mem_cgroup_threshold(struct mem_cgroup *memcg) |
| { |
| while (memcg) { |
| __mem_cgroup_threshold(memcg, false); |
| if (do_memsw_account()) |
| __mem_cgroup_threshold(memcg, true); |
| |
| memcg = parent_mem_cgroup(memcg); |
| } |
| } |
| |
| static int compare_thresholds(const void *a, const void *b) |
| { |
| const struct mem_cgroup_threshold *_a = a; |
| const struct mem_cgroup_threshold *_b = b; |
| |
| if (_a->threshold > _b->threshold) |
| return 1; |
| |
| if (_a->threshold < _b->threshold) |
| return -1; |
| |
| return 0; |
| } |
| |
| static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg) |
| { |
| struct mem_cgroup_eventfd_list *ev; |
| |
| spin_lock(&memcg_oom_lock); |
| |
| list_for_each_entry(ev, &memcg->oom_notify, list) |
| eventfd_signal(ev->eventfd, 1); |
| |
| spin_unlock(&memcg_oom_lock); |
| return 0; |
| } |
| |
| static void mem_cgroup_oom_notify(struct mem_cgroup *memcg) |
| { |
| struct mem_cgroup *iter; |
| |
| for_each_mem_cgroup_tree(iter, memcg) |
| mem_cgroup_oom_notify_cb(iter); |
| } |
| |
| static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg, |
| struct eventfd_ctx *eventfd, const char *args, enum res_type type) |
| { |
| struct mem_cgroup_thresholds *thresholds; |
| struct mem_cgroup_threshold_ary *new; |
| unsigned long threshold; |
| unsigned long usage; |
| int i, size, ret; |
| |
| ret = page_counter_memparse(args, "-1", &threshold); |
| if (ret) |
| return ret; |
| |
| mutex_lock(&memcg->thresholds_lock); |
| |
| if (type == _MEM) { |
| thresholds = &memcg->thresholds; |
| usage = mem_cgroup_usage(memcg, false); |
| } else if (type == _MEMSWAP) { |
| thresholds = &memcg->memsw_thresholds; |
| usage = mem_cgroup_usage(memcg, true); |
| } else |
| BUG(); |
| |
| /* Check if a threshold crossed before adding a new one */ |
| if (thresholds->primary) |
| __mem_cgroup_threshold(memcg, type == _MEMSWAP); |
| |
| size = thresholds->primary ? thresholds->primary->size + 1 : 1; |
| |
| /* Allocate memory for new array of thresholds */ |
| new = kmalloc(struct_size(new, entries, size), GFP_KERNEL); |
| if (!new) { |
| ret = -ENOMEM; |
| goto unlock; |
| } |
| new->size = size; |
| |
| /* Copy thresholds (if any) to new array */ |
| if (thresholds->primary) |
| memcpy(new->entries, thresholds->primary->entries, |
| flex_array_size(new, entries, size - 1)); |
| |
| /* Add new threshold */ |
| new->entries[size - 1].eventfd = eventfd; |
| new->entries[size - 1].threshold = threshold; |
| |
| /* Sort thresholds. Registering of new threshold isn't time-critical */ |
| sort(new->entries, size, sizeof(*new->entries), |
| compare_thresholds, NULL); |
| |
| /* Find current threshold */ |
| new->current_threshold = -1; |
| for (i = 0; i < size; i++) { |
| if (new->entries[i].threshold <= usage) { |
| /* |
| * new->current_threshold will not be used until |
| * rcu_assign_pointer(), so it's safe to increment |
| * it here. |
| */ |
| ++new->current_threshold; |
| } else |
| break; |
| } |
| |
| /* Free old spare buffer and save old primary buffer as spare */ |
| kfree(thresholds->spare); |
| thresholds->spare = thresholds->primary; |
| |
| rcu_assign_pointer(thresholds->primary, new); |
| |
| /* To be sure that nobody uses thresholds */ |
| synchronize_rcu(); |
| |
| unlock: |
| mutex_unlock(&memcg->thresholds_lock); |
| |
| return ret; |
| } |
| |
| static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg, |
| struct eventfd_ctx *eventfd, const char *args) |
| { |
| return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM); |
| } |
| |
| static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg, |
| struct eventfd_ctx *eventfd, const char *args) |
| { |
| return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP); |
| } |
| |
| static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg, |
| struct eventfd_ctx *eventfd, enum res_type type) |
| { |
| struct mem_cgroup_thresholds *thresholds; |
| struct mem_cgroup_threshold_ary *new; |
| unsigned long usage; |
| int i, j, size, entries; |
| |
| mutex_lock(&memcg->thresholds_lock); |
| |
| if (type == _MEM) { |
| thresholds = &memcg->thresholds; |
| usage = mem_cgroup_usage(memcg, false); |
| } else if (type == _MEMSWAP) { |
| thresholds = &memcg->memsw_thresholds; |
| usage = mem_cgroup_usage(memcg, true); |
| } else |
| BUG(); |
| |
| if (!thresholds->primary) |
| goto unlock; |
| |
| /* Check if a threshold crossed before removing */ |
| __mem_cgroup_threshold(memcg, type == _MEMSWAP); |
| |
| /* Calculate new number of threshold */ |
| size = entries = 0; |
| for (i = 0; i < thresholds->primary->size; i++) { |
| if (thresholds->primary->entries[i].eventfd != eventfd) |
| size++; |
| else |
| entries++; |
| } |
| |
| new = thresholds->spare; |
| |
| /* If no items related to eventfd have been cleared, nothing to do */ |
| if (!entries) |
| goto unlock; |
| |
| /* Set thresholds array to NULL if we don't have thresholds */ |
| if (!size) { |
| kfree(new); |
| new = NULL; |
| goto swap_buffers; |
| } |
| |
| new->size = size; |
| |
| /* Copy thresholds and find current threshold */ |
| new->current_threshold = -1; |
| for (i = 0, j = 0; i < thresholds->primary->size; i++) { |
| if (thresholds->primary->entries[i].eventfd == eventfd) |
| continue; |
| |
| new->entries[j] = thresholds->primary->entries[i]; |
| if (new->entries[j].threshold <= usage) { |
| /* |
| * new->current_threshold will not be used |
| * until rcu_assign_pointer(), so it's safe to increment |
| * it here. |
| */ |
| ++new->current_threshold; |
| } |
| j++; |
| } |
| |
| swap_buffers: |
| /* Swap primary and spare array */ |
| thresholds->spare = thresholds->primary; |
| |
| rcu_assign_pointer(thresholds->primary, new); |
| |
| /* To be sure that nobody uses thresholds */ |
| synchronize_rcu(); |
| |
| /* If all events are unregistered, free the spare array */ |
| if (!new) { |
| kfree(thresholds->spare); |
| thresholds->spare = NULL; |
| } |
| unlock: |
| mutex_unlock(&memcg->thresholds_lock); |
| } |
| |
| static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg, |
| struct eventfd_ctx *eventfd) |
| { |
| return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM); |
| } |
| |
| static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg, |
| struct eventfd_ctx *eventfd) |
| { |
| return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP); |
| } |
| |
| static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg, |
| struct eventfd_ctx *eventfd, const char *args) |
| { |
| struct mem_cgroup_eventfd_list *event; |
| |
| event = kmalloc(sizeof(*event), GFP_KERNEL); |
| if (!event) |
| return -ENOMEM; |
| |
| spin_lock(&memcg_oom_lock); |
| |
| event->eventfd = eventfd; |
| list_add(&event->list, &memcg->oom_notify); |
| |
| /* already in OOM ? */ |
| if (memcg->under_oom) |
| eventfd_signal(eventfd, 1); |
| spin_unlock(&memcg_oom_lock); |
| |
| return 0; |
| } |
| |
| static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg, |
| struct eventfd_ctx *eventfd) |
| { |
| struct mem_cgroup_eventfd_list *ev, *tmp; |
| |
| spin_lock(&memcg_oom_lock); |
| |
| list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) { |
| if (ev->eventfd == eventfd) { |
| list_del(&ev->list); |
| kfree(ev); |
| } |
| } |
| |
| spin_unlock(&memcg_oom_lock); |
| } |
| |
| static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_seq(sf); |
| |
| seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable); |
| seq_printf(sf, "under_oom %d\n", (bool)memcg->under_oom); |
| seq_printf(sf, "oom_kill %lu\n", |
| atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL])); |
| return 0; |
| } |
| |
| static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css, |
| struct cftype *cft, u64 val) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
| |
| /* cannot set to root cgroup and only 0 and 1 are allowed */ |
| if (!css->parent || !((val == 0) || (val == 1))) |
| return -EINVAL; |
| |
| memcg->oom_kill_disable = val; |
| if (!val) |
| memcg_oom_recover(memcg); |
| |
| return 0; |
| } |
| |
| #ifdef CONFIG_CGROUP_WRITEBACK |
| |
| #include <trace/events/writeback.h> |
| |
| static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp) |
| { |
| return wb_domain_init(&memcg->cgwb_domain, gfp); |
| } |
| |
| static void memcg_wb_domain_exit(struct mem_cgroup *memcg) |
| { |
| wb_domain_exit(&memcg->cgwb_domain); |
| } |
| |
| static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg) |
| { |
| wb_domain_size_changed(&memcg->cgwb_domain); |
| } |
| |
| struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css); |
| |
| if (!memcg->css.parent) |
| return NULL; |
| |
| return &memcg->cgwb_domain; |
| } |
| |
| /* |
| * idx can be of type enum memcg_stat_item or node_stat_item. |
| * Keep in sync with memcg_exact_page(). |
| */ |
| static unsigned long memcg_exact_page_state(struct mem_cgroup *memcg, int idx) |
| { |
| long x = atomic_long_read(&memcg->vmstats[idx]); |
| int cpu; |
| |
| for_each_online_cpu(cpu) |
| x += per_cpu_ptr(memcg->vmstats_percpu, cpu)->stat[idx]; |
| if (x < 0) |
| x = 0; |
| return x; |
| } |
| |
| /** |
| * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg |
| * @wb: bdi_writeback in question |
| * @pfilepages: out parameter for number of file pages |
| * @pheadroom: out parameter for number of allocatable pages according to memcg |
| * @pdirty: out parameter for number of dirty pages |
| * @pwriteback: out parameter for number of pages under writeback |
| * |
| * Determine the numbers of file, headroom, dirty, and writeback pages in |
| * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom |
| * is a bit more involved. |
| * |
| * A memcg's headroom is "min(max, high) - used". In the hierarchy, the |
| * headroom is calculated as the lowest headroom of itself and the |
| * ancestors. Note that this doesn't consider the actual amount of |
| * available memory in the system. The caller should further cap |
| * *@pheadroom accordingly. |
| */ |
| void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages, |
| unsigned long *pheadroom, unsigned long *pdirty, |
| unsigned long *pwriteback) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css); |
| struct mem_cgroup *parent; |
| |
| *pdirty = memcg_exact_page_state(memcg, NR_FILE_DIRTY); |
| |
| *pwriteback = memcg_exact_page_state(memcg, NR_WRITEBACK); |
| *pfilepages = memcg_exact_page_state(memcg, NR_INACTIVE_FILE) + |
| memcg_exact_page_state(memcg, NR_ACTIVE_FILE); |
| *pheadroom = PAGE_COUNTER_MAX; |
| |
| while ((parent = parent_mem_cgroup(memcg))) { |
| unsigned long ceiling = min(READ_ONCE(memcg->memory.max), |
| READ_ONCE(memcg->memory.high)); |
| unsigned long used = page_counter_read(&memcg->memory); |
| |
| *pheadroom = min(*pheadroom, ceiling - min(ceiling, used)); |
| memcg = parent; |
| } |
| } |
| |
| /* |
| * Foreign dirty flushing |
| * |
| * There's an inherent mismatch between memcg and writeback. The former |
| * trackes ownership per-page while the latter per-inode. This was a |
| * deliberate design decision because honoring per-page ownership in the |
| * writeback path is complicated, may lead to higher CPU and IO overheads |
| * and deemed unnecessary given that write-sharing an inode across |
| * different cgroups isn't a common use-case. |
| * |
| * Combined with inode majority-writer ownership switching, this works well |
| * enough in most cases but there are some pathological cases. For |
| * example, let's say there are two cgroups A and B which keep writing to |
| * different but confined parts of the same inode. B owns the inode and |
| * A's memory is limited far below B's. A's dirty ratio can rise enough to |
| * trigger balance_dirty_pages() sleeps but B's can be low enough to avoid |
| * triggering background writeback. A will be slowed down without a way to |
| * make writeback of the dirty pages happen. |
| * |
| * Conditions like the above can lead to a cgroup getting repatedly and |
| * severely throttled after making some progress after each |
| * dirty_expire_interval while the underyling IO device is almost |
| * completely idle. |
| * |
| * Solving this problem completely requires matching the ownership tracking |
| * granularities between memcg and writeback in either direction. However, |
| * the more egregious behaviors can be avoided by simply remembering the |
| * most recent foreign dirtying events and initiating remote flushes on |
| * them when local writeback isn't enough to keep the memory clean enough. |
| * |
| * The following two functions implement such mechanism. When a foreign |
| * page - a page whose memcg and writeback ownerships don't match - is |
| * dirtied, mem_cgroup_track_foreign_dirty() records the inode owning |
| * bdi_writeback on the page owning memcg. When balance_dirty_pages() |
| * decides that the memcg needs to sleep due to high dirty ratio, it calls |
| * mem_cgroup_flush_foreign() which queues writeback on the recorded |
| * foreign bdi_writebacks which haven't expired. Both the numbers of |
| * recorded bdi_writebacks and concurrent in-flight foreign writebacks are |
| * limited to MEMCG_CGWB_FRN_CNT. |
| * |
| * The mechanism only remembers IDs and doesn't hold any object references. |
| * As being wrong occasionally doesn't matter, updates and accesses to the |
| * records are lockless and racy. |
| */ |
| void mem_cgroup_track_foreign_dirty_slowpath(struct page *page, |
| struct bdi_writeback *wb) |
| { |
| struct mem_cgroup *memcg = page_memcg(page); |
| struct memcg_cgwb_frn *frn; |
| u64 now = get_jiffies_64(); |
| u64 oldest_at = now; |
| int oldest = -1; |
| int i; |
| |
| trace_track_foreign_dirty(page, wb); |
| |
| /* |
| * Pick the slot to use. If there is already a slot for @wb, keep |
| * using it. If not replace the oldest one which isn't being |
| * written out. |
| */ |
| for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) { |
| frn = &memcg->cgwb_frn[i]; |
| if (frn->bdi_id == wb->bdi->id && |
| frn->memcg_id == wb->memcg_css->id) |
| break; |
| if (time_before64(frn->at, oldest_at) && |
| atomic_read(&frn->done.cnt) == 1) { |
| oldest = i; |
| oldest_at = frn->at; |
| } |
| } |
| |
| if (i < MEMCG_CGWB_FRN_CNT) { |
| /* |
| * Re-using an existing one. Update timestamp lazily to |
| * avoid making the cacheline hot. We want them to be |
| * reasonably up-to-date and significantly shorter than |
| * dirty_expire_interval as that's what expires the record. |
| * Use the shorter of 1s and dirty_expire_interval / 8. |
| */ |
| unsigned long update_intv = |
| min_t(unsigned long, HZ, |
| msecs_to_jiffies(dirty_expire_interval * 10) / 8); |
| |
| if (time_before64(frn->at, now - update_intv)) |
| frn->at = now; |
| } else if (oldest >= 0) { |
| /* replace the oldest free one */ |
| frn = &memcg->cgwb_frn[oldest]; |
| frn->bdi_id = wb->bdi->id; |
| frn->memcg_id = wb->memcg_css->id; |
| frn->at = now; |
| } |
| } |
| |
| /* issue foreign writeback flushes for recorded foreign dirtying events */ |
| void mem_cgroup_flush_foreign(struct bdi_writeback *wb) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css); |
| unsigned long intv = msecs_to_jiffies(dirty_expire_interval * 10); |
| u64 now = jiffies_64; |
| int i; |
| |
| for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) { |
| struct memcg_cgwb_frn *frn = &memcg->cgwb_frn[i]; |
| |
| /* |
| * If the record is older than dirty_expire_interval, |
| * writeback on it has already started. No need to kick it |
| * off again. Also, don't start a new one if there's |
| * already one in flight. |
| */ |
| if (time_after64(frn->at, now - intv) && |
| atomic_read(&frn->done.cnt) == 1) { |
| frn->at = 0; |
| trace_flush_foreign(wb, frn->bdi_id, frn->memcg_id); |
| cgroup_writeback_by_id(frn->bdi_id, frn->memcg_id, 0, |
| WB_REASON_FOREIGN_FLUSH, |
| &frn->done); |
| } |
| } |
| } |
| |
| #else /* CONFIG_CGROUP_WRITEBACK */ |
| |
| static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp) |
| { |
| return 0; |
| } |
| |
| static void memcg_wb_domain_exit(struct mem_cgroup *memcg) |
| { |
| } |
| |
| static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg) |
| { |
| } |
| |
| #endif /* CONFIG_CGROUP_WRITEBACK */ |
| |
| /* |
| * DO NOT USE IN NEW FILES. |
| * |
| * "cgroup.event_control" implementation. |
| * |
| * This is way over-engineered. It tries to support fully configurable |
| * events for each user. Such level of flexibility is completely |
| * unnecessary especially in the light of the planned unified hierarchy. |
| * |
| * Please deprecate this and replace with something simpler if at all |
| * possible. |
| */ |
| |
| /* |
| * Unregister event and free resources. |
| * |
| * Gets called from workqueue. |
| */ |
| static void memcg_event_remove(struct work_struct *work) |
| { |
| struct mem_cgroup_event *event = |
| container_of(work, struct mem_cgroup_event, remove); |
| struct mem_cgroup *memcg = event->memcg; |
| |
| remove_wait_queue(event->wqh, &event->wait); |
| |
| event->unregister_event(memcg, event->eventfd); |
| |
| /* Notify userspace the event is going away. */ |
| eventfd_signal(event->eventfd, 1); |
| |
| eventfd_ctx_put(event->eventfd); |
| kfree(event); |
| css_put(&memcg->css); |
| } |
| |
| /* |
| * Gets called on EPOLLHUP on eventfd when user closes it. |
| * |
| * Called with wqh->lock held and interrupts disabled. |
| */ |
| static int memcg_event_wake(wait_queue_entry_t *wait, unsigned mode, |
| int sync, void *key) |
| { |
| struct mem_cgroup_event *event = |
| container_of(wait, struct mem_cgroup_event, wait); |
| struct mem_cgroup *memcg = event->memcg; |
| __poll_t flags = key_to_poll(key); |
| |
| if (flags & EPOLLHUP) { |
| /* |
| * If the event has been detached at cgroup removal, we |
| * can simply return knowing the other side will cleanup |
| * for us. |
| * |
| * We can't race against event freeing since the other |
| * side will require wqh->lock via remove_wait_queue(), |
| * which we hold. |
| */ |
| spin_lock(&memcg->event_list_lock); |
| if (!list_empty(&event->list)) { |
| list_del_init(&event->list); |
| /* |
| * We are in atomic context, but cgroup_event_remove() |
| * may sleep, so we have to call it in workqueue. |
| */ |
| schedule_work(&event->remove); |
| } |
| spin_unlock(&memcg->event_list_lock); |
| } |
| |
| return 0; |
| } |
| |
| static void memcg_event_ptable_queue_proc(struct file *file, |
| wait_queue_head_t *wqh, poll_table *pt) |
| { |
| struct mem_cgroup_event *event = |
| container_of(pt, struct mem_cgroup_event, pt); |
| |
| event->wqh = wqh; |
| add_wait_queue(wqh, &event->wait); |
| } |
| |
| /* |
| * DO NOT USE IN NEW FILES. |
| * |
| * Parse input and register new cgroup event handler. |
| * |
| * Input must be in format '<event_fd> <control_fd> <args>'. |
| * Interpretation of args is defined by control file implementation. |
| */ |
| static ssize_t memcg_write_event_control(struct kernfs_open_file *of, |
| char *buf, size_t nbytes, loff_t off) |
| { |
| struct cgroup_subsys_state *css = of_css(of); |
| struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
| struct mem_cgroup_event *event; |
| struct cgroup_subsys_state *cfile_css; |
| unsigned int efd, cfd; |
| struct fd efile; |
| struct fd cfile; |
| const char *name; |
| char *endp; |
| int ret; |
| |
| buf = strstrip(buf); |
| |
| efd = simple_strtoul(buf, &endp, 10); |
| if (*endp != ' ') |
| return -EINVAL; |
| buf = endp + 1; |
| |
| cfd = simple_strtoul(buf, &endp, 10); |
| if ((*endp != ' ') && (*endp != '\0')) |
| return -EINVAL; |
| buf = endp + 1; |
| |
| event = kzalloc(sizeof(*event), GFP_KERNEL); |
| if (!event) |
| return -ENOMEM; |
| |
| event->memcg = memcg; |
| INIT_LIST_HEAD(&event->list); |
| init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc); |
| init_waitqueue_func_entry(&event->wait, memcg_event_wake); |
| INIT_WORK(&event->remove, memcg_event_remove); |
| |
| efile = fdget(efd); |
| if (!efile.file) { |
| ret = -EBADF; |
| goto out_kfree; |
| } |
| |
| event->eventfd = eventfd_ctx_fileget(efile.file); |
| if (IS_ERR(event->eventfd)) { |
| ret = PTR_ERR(event->eventfd); |
| goto out_put_efile; |
| } |
| |
| cfile = fdget(cfd); |
| if (!cfile.file) { |
| ret = -EBADF; |
| goto out_put_eventfd; |
| } |
| |
| /* the process need read permission on control file */ |
| /* AV: shouldn't we check that it's been opened for read instead? */ |
| ret = file_permission(cfile.file, MAY_READ); |
| if (ret < 0) |
| goto out_put_cfile; |
| |
| /* |
| * Determine the event callbacks and set them in @event. This used |
| * to be done via struct cftype but cgroup core no longer knows |
| * about these events. The following is crude but the whole thing |
| * is for compatibility anyway. |
| * |
| * DO NOT ADD NEW FILES. |
| */ |
| name = cfile.file->f_path.dentry->d_name.name; |
| |
| if (!strcmp(name, "memory.usage_in_bytes")) { |
| event->register_event = mem_cgroup_usage_register_event; |
| event->unregister_event = mem_cgroup_usage_unregister_event; |
| } else if (!strcmp(name, "memory.oom_control")) { |
| event->register_event = mem_cgroup_oom_register_event; |
| event->unregister_event = mem_cgroup_oom_unregister_event; |
| } else if (!strcmp(name, "memory.pressure_level")) { |
| event->register_event = vmpressure_register_event; |
| event->unregister_event = vmpressure_unregister_event; |
| } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) { |
| event->register_event = memsw_cgroup_usage_register_event; |
| event->unregister_event = memsw_cgroup_usage_unregister_event; |
| } else { |
| ret = -EINVAL; |
| goto out_put_cfile; |
| } |
| |
| /* |
| * Verify @cfile should belong to @css. Also, remaining events are |
| * automatically removed on cgroup destruction but the removal is |
| * asynchronous, so take an extra ref on @css. |
| */ |
| cfile_css = css_tryget_online_from_dir(cfile.file->f_path.dentry->d_parent, |
| &memory_cgrp_subsys); |
| ret = -EINVAL; |
| if (IS_ERR(cfile_css)) |
| goto out_put_cfile; |
| if (cfile_css != css) { |
| css_put(cfile_css); |
| goto out_put_cfile; |
| } |
| |
| ret = event->register_event(memcg, event->eventfd, buf); |
| if (ret) |
| goto out_put_css; |
| |
| vfs_poll(efile.file, &event->pt); |
| |
| spin_lock(&memcg->event_list_lock); |
| list_add(&event->list, &memcg->event_list); |
| spin_unlock(&memcg->event_list_lock); |
| |
| fdput(cfile); |
| fdput(efile); |
| |
| return nbytes; |
| |
| out_put_css: |
| css_put(css); |
| out_put_cfile: |
| fdput(cfile); |
| out_put_eventfd: |
| eventfd_ctx_put(event->eventfd); |
| out_put_efile: |
| fdput(efile); |
| out_kfree: |
| kfree(event); |
| |
| return ret; |
| } |
| |
| static struct cftype mem_cgroup_legacy_files[] = { |
| { |
| .name = "usage_in_bytes", |
| .private = MEMFILE_PRIVATE(_MEM, RES_USAGE), |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| { |
| .name = "max_usage_in_bytes", |
| .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE), |
| .write = mem_cgroup_reset, |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| { |
| .name = "limit_in_bytes", |
| .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT), |
| .write = mem_cgroup_write, |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| { |
| .name = "soft_limit_in_bytes", |
| .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT), |
| .write = mem_cgroup_write, |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| { |
| .name = "failcnt", |
| .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT), |
| .write = mem_cgroup_reset, |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| { |
| .name = "stat", |
| .seq_show = memcg_stat_show, |
| }, |
| { |
| .name = "force_empty", |
| .write = mem_cgroup_force_empty_write, |
| }, |
| { |
| .name = "use_hierarchy", |
| .write_u64 = mem_cgroup_hierarchy_write, |
| .read_u64 = mem_cgroup_hierarchy_read, |
| }, |
| { |
| .name = "cgroup.event_control", /* XXX: for compat */ |
| .write = memcg_write_event_control, |
| .flags = CFTYPE_NO_PREFIX | CFTYPE_WORLD_WRITABLE, |
| }, |
| { |
| .name = "swappiness", |
| .read_u64 = mem_cgroup_swappiness_read, |
| .write_u64 = mem_cgroup_swappiness_write, |
| }, |
| { |
| .name = "move_charge_at_immigrate", |
| .read_u64 = mem_cgroup_move_charge_read, |
| .write_u64 = mem_cgroup_move_charge_write, |
| }, |
| { |
| .name = "oom_control", |
| .seq_show = mem_cgroup_oom_control_read, |
| .write_u64 = mem_cgroup_oom_control_write, |
| .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL), |
| }, |
| { |
| .name = "pressure_level", |
| }, |
| #ifdef CONFIG_NUMA |
| { |
| .name = "numa_stat", |
| .seq_show = memcg_numa_stat_show, |
| }, |
| #endif |
| { |
| .name = "kmem.limit_in_bytes", |
| .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT), |
| .write = mem_cgroup_write, |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| { |
| .name = "kmem.usage_in_bytes", |
| .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE), |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| { |
| .name = "kmem.failcnt", |
| .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT), |
| .write = mem_cgroup_reset, |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| { |
| .name = "kmem.max_usage_in_bytes", |
| .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE), |
| .write = mem_cgroup_reset, |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| #if defined(CONFIG_MEMCG_KMEM) && \ |
| (defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)) |
| { |
| .name = "kmem.slabinfo", |
| .seq_show = memcg_slab_show, |
| }, |
| #endif |
| { |
| .name = "kmem.tcp.limit_in_bytes", |
| .private = MEMFILE_PRIVATE(_TCP, RES_LIMIT), |
| .write = mem_cgroup_write, |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| { |
| .name = "kmem.tcp.usage_in_bytes", |
| .private = MEMFILE_PRIVATE(_TCP, RES_USAGE), |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| { |
| .name = "kmem.tcp.failcnt", |
| .private = MEMFILE_PRIVATE(_TCP, RES_FAILCNT), |
| .write = mem_cgroup_reset, |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| { |
| .name = "kmem.tcp.max_usage_in_bytes", |
| .private = MEMFILE_PRIVATE(_TCP, RES_MAX_USAGE), |
| .write = mem_cgroup_reset, |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| { }, /* terminate */ |
| }; |
| |
| /* |
| * Private memory cgroup IDR |
| * |
| * Swap-out records and page cache shadow entries need to store memcg |
| * references in constrained space, so we maintain an ID space that is |
| * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of |
| * memory-controlled cgroups to 64k. |
| * |
| * However, there usually are many references to the offline CSS after |
| * the cgroup has been destroyed, such as page cache or reclaimable |
| * slab objects, that don't need to hang on to the ID. We want to keep |
| * those dead CSS from occupying IDs, or we might quickly exhaust the |
| * relatively small ID space and prevent the creation of new cgroups |
| * even when there are much fewer than 64k cgroups - possibly none. |
| * |
| * Maintain a private 16-bit ID space for memcg, and allow the ID to |
| * be freed and recycled when it's no longer needed, which is usually |
| * when the CSS is offlined. |
| * |
| * The only exception to that are records of swapped out tmpfs/shmem |
| * pages that need to be attributed to live ancestors on swapin. But |
| * those references are manageable from userspace. |
| */ |
| |
| static DEFINE_IDR(mem_cgroup_idr); |
| |
| static void mem_cgroup_id_remove(struct mem_cgroup *memcg) |
| { |
| if (memcg->id.id > 0) { |
| idr_remove(&mem_cgroup_idr, memcg->id.id); |
| memcg->id.id = 0; |
| } |
| } |
| |
| static void __maybe_unused mem_cgroup_id_get_many(struct mem_cgroup *memcg, |
| unsigned int n) |
| { |
| refcount_add(n, &memcg->id.ref); |
| } |
| |
| static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n) |
| { |
| if (refcount_sub_and_test(n, &memcg->id.ref)) { |
| mem_cgroup_id_remove(memcg); |
| |
| /* Memcg ID pins CSS */ |
| css_put(&memcg->css); |
| } |
| } |
| |
| static inline void mem_cgroup_id_put(struct mem_cgroup *memcg) |
| { |
| mem_cgroup_id_put_many(memcg, 1); |
| } |
| |
| /** |
| * mem_cgroup_from_id - look up a memcg from a memcg id |
| * @id: the memcg id to look up |
| * |
| * Caller must hold rcu_read_lock(). |
| */ |
| struct mem_cgroup *mem_cgroup_from_id(unsigned short id) |
| { |
| WARN_ON_ONCE(!rcu_read_lock_held()); |
| return idr_find(&mem_cgroup_idr, id); |
| } |
| |
| static int alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node) |
| { |
| struct mem_cgroup_per_node *pn; |
| int tmp = node; |
| /* |
| * This routine is called against possible nodes. |
| * But it's BUG to call kmalloc() against offline node. |
| * |
| * TODO: this routine can waste much memory for nodes which will |
| * never be onlined. It's better to use memory hotplug callback |
| * function. |
| */ |
| if (!node_state(node, N_NORMAL_MEMORY)) |
| tmp = -1; |
| pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp); |
| if (!pn) |
| return 1; |
| |
| pn->lruvec_stat_local = alloc_percpu_gfp(struct lruvec_stat, |
| GFP_KERNEL_ACCOUNT); |
| if (!pn->lruvec_stat_local) { |
| kfree(pn); |
| return 1; |
| } |
| |
| pn->lruvec_stat_cpu = alloc_percpu_gfp(struct lruvec_stat, |
| GFP_KERNEL_ACCOUNT); |
| if (!pn->lruvec_stat_cpu) { |
| free_percpu(pn->lruvec_stat_local); |
| kfree(pn); |
| return 1; |
| } |
| |
| lruvec_init(&pn->lruvec); |
| pn->usage_in_excess = 0; |
| pn->on_tree = false; |
| pn->memcg = memcg; |
| |
| memcg->nodeinfo[node] = pn; |
| return 0; |
| } |
| |
| static void free_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node) |
| { |
| struct mem_cgroup_per_node *pn = memcg->nodeinfo[node]; |
| |
| if (!pn) |
| return; |
| |
| free_percpu(pn->lruvec_stat_cpu); |
| free_percpu(pn->lruvec_stat_local); |
| kfree(pn); |
| } |
| |
| static void __mem_cgroup_free(struct mem_cgroup *memcg) |
| { |
| int node; |
| |
| for_each_node(node) |
| free_mem_cgroup_per_node_info(memcg, node); |
| free_percpu(memcg->vmstats_percpu); |
| free_percpu(memcg->vmstats_local); |
| kfree(memcg); |
| } |
| |
| static void mem_cgroup_free(struct mem_cgroup *memcg) |
| { |
| memcg_wb_domain_exit(memcg); |
| /* |
| * Flush percpu vmstats and vmevents to guarantee the value correctness |
| * on parent's and all ancestor levels. |
| */ |
| memcg_flush_percpu_vmstats(memcg); |
| memcg_flush_percpu_vmevents(memcg); |
| __mem_cgroup_free(memcg); |
| } |
| |
| static struct mem_cgroup *mem_cgroup_alloc(void) |
| { |
| struct mem_cgroup *memcg; |
| unsigned int size; |
| int node; |
| int __maybe_unused i; |
| long error = -ENOMEM; |
| |
| size = sizeof(struct mem_cgroup); |
| size += nr_node_ids * sizeof(struct mem_cgroup_per_node *); |
| |
| memcg = kzalloc(size, GFP_KERNEL); |
| if (!memcg) |
| return ERR_PTR(error); |
| |
| memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL, |
| 1, MEM_CGROUP_ID_MAX, |
| GFP_KERNEL); |
| if (memcg->id.id < 0) { |
| error = memcg->id.id; |
| goto fail; |
| } |
| |
| memcg->vmstats_local = alloc_percpu_gfp(struct memcg_vmstats_percpu, |
| GFP_KERNEL_ACCOUNT); |
| if (!memcg->vmstats_local) |
| goto fail; |
| |
| memcg->vmstats_percpu = alloc_percpu_gfp(struct memcg_vmstats_percpu, |
| GFP_KERNEL_ACCOUNT); |
| if (!memcg->vmstats_percpu) |
| goto fail; |
| |
| for_each_node(node) |
| if (alloc_mem_cgroup_per_node_info(memcg, node)) |
| goto fail; |
| |
| if (memcg_wb_domain_init(memcg, GFP_KERNEL)) |
| goto fail; |
| |
| INIT_WORK(&memcg->high_work, high_work_func); |
| INIT_LIST_HEAD(&memcg->oom_notify); |
| mutex_init(&memcg->thresholds_lock); |
| spin_lock_init(&memcg->move_lock); |
| vmpressure_init(&memcg->vmpressure); |
| INIT_LIST_HEAD(&memcg->event_list); |
| spin_lock_init(&memcg->event_list_lock); |
| memcg->socket_pressure = jiffies; |
| #ifdef CONFIG_MEMCG_KMEM |
| memcg->kmemcg_id = -1; |
| INIT_LIST_HEAD(&memcg->objcg_list); |
| #endif |
| #ifdef CONFIG_CGROUP_WRITEBACK |
| INIT_LIST_HEAD(&memcg->cgwb_list); |
| for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) |
| memcg->cgwb_frn[i].done = |
| __WB_COMPLETION_INIT(&memcg_cgwb_frn_waitq); |
| #endif |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| spin_lock_init(&memcg->deferred_split_queue.split_queue_lock); |
| INIT_LIST_HEAD(&memcg->deferred_split_queue.split_queue); |
| memcg->deferred_split_queue.split_queue_len = 0; |
| #endif |
| idr_replace(&mem_cgroup_idr, memcg, memcg->id.id); |
| return memcg; |
| fail: |
| mem_cgroup_id_remove(memcg); |
| __mem_cgroup_free(memcg); |
| return ERR_PTR(error); |
| } |
| |
| static struct cgroup_subsys_state * __ref |
| mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) |
| { |
| struct mem_cgroup *parent = mem_cgroup_from_css(parent_css); |
| struct mem_cgroup *memcg, *old_memcg; |
| long error = -ENOMEM; |
| |
| old_memcg = set_active_memcg(parent); |
| memcg = mem_cgroup_alloc(); |
| set_active_memcg(old_memcg); |
| if (IS_ERR(memcg)) |
| return ERR_CAST(memcg); |
| |
| page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX); |
| memcg->soft_limit = PAGE_COUNTER_MAX; |
| page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX); |
| if (parent) { |
| memcg->swappiness = mem_cgroup_swappiness(parent); |
| memcg->oom_kill_disable = parent->oom_kill_disable; |
| |
| page_counter_init(&memcg->memory, &parent->memory); |
| page_counter_init(&memcg->swap, &parent->swap); |
| page_counter_init(&memcg->kmem, &parent->kmem); |
| page_counter_init(&memcg->tcpmem, &parent->tcpmem); |
| } else { |
| page_counter_init(&memcg->memory, NULL); |
| page_counter_init(&memcg->swap, NULL); |
| page_counter_init(&memcg->kmem, NULL); |
| page_counter_init(&memcg->tcpmem, NULL); |
| |
| root_mem_cgroup = memcg; |
| return &memcg->css; |
| } |
| |
| /* The following stuff does not apply to the root */ |
| error = memcg_online_kmem(memcg); |
| if (error) |
| goto fail; |
| |
| if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket) |
| static_branch_inc(&memcg_sockets_enabled_key); |
| |
| return &memcg->css; |
| fail: |
| mem_cgroup_id_remove(memcg); |
| mem_cgroup_free(memcg); |
| return ERR_PTR(error); |
| } |
| |
| static int mem_cgroup_css_online(struct cgroup_subsys_state *css) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
| |
| /* |
| * A memcg must be visible for memcg_expand_shrinker_maps() |
| * by the time the maps are allocated. So, we allocate maps |
| * here, when for_each_mem_cgroup() can't skip it. |
| */ |
| if (memcg_alloc_shrinker_maps(memcg)) { |
| mem_cgroup_id_remove(memcg); |
| return -ENOMEM; |
| } |
| |
| /* Online state pins memcg ID, memcg ID pins CSS */ |
| refcount_set(&memcg->id.ref, 1); |
| css_get(css); |
| return 0; |
| } |
| |
| static void mem_cgroup_css_offline(struct cgroup_subsys_state *css) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
| struct mem_cgroup_event *event, *tmp; |
| |
| /* |
| * Unregister events and notify userspace. |
| * Notify userspace about cgroup removing only after rmdir of cgroup |
| * directory to avoid race between userspace and kernelspace. |
| */ |
| spin_lock(&memcg->event_list_lock); |
| list_for_each_entry_safe(event, tmp, &memcg->event_list, list) { |
| list_del_init(&event->list); |
| schedule_work(&event->remove); |
| } |
| spin_unlock(&memcg->event_list_lock); |
| |
| page_counter_set_min(&memcg->memory, 0); |
| page_counter_set_low(&memcg->memory, 0); |
| |
| memcg_offline_kmem(memcg); |
| wb_memcg_offline(memcg); |
| |
| drain_all_stock(memcg); |
| |
| mem_cgroup_id_put(memcg); |
| } |
| |
| static void mem_cgroup_css_released(struct cgroup_subsys_state *css) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
| |
| invalidate_reclaim_iterators(memcg); |
| } |
| |
| static void mem_cgroup_css_free(struct cgroup_subsys_state *css) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
| int __maybe_unused i; |
| |
| #ifdef CONFIG_CGROUP_WRITEBACK |
| for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) |
| wb_wait_for_completion(&memcg->cgwb_frn[i].done); |
| #endif |
| if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket) |
| static_branch_dec(&memcg_sockets_enabled_key); |
| |
| if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_active) |
| static_branch_dec(&memcg_sockets_enabled_key); |
| |
| vmpressure_cleanup(&memcg->vmpressure); |
| cancel_work_sync(&memcg->high_work); |
| mem_cgroup_remove_from_trees(memcg); |
| memcg_free_shrinker_maps(memcg); |
| memcg_free_kmem(memcg); |
| mem_cgroup_free(memcg); |
| } |
| |
| /** |
| * mem_cgroup_css_reset - reset the states of a mem_cgroup |
| * @css: the target css |
| * |
| * Reset the states of the mem_cgroup associated with @css. This is |
| * invoked when the userland requests disabling on the default hierarchy |
| * but the memcg is pinned through dependency. The memcg should stop |
| * applying policies and should revert to the vanilla state as it may be |
| * made visible again. |
| * |
| * The current implementation only resets the essential configurations. |
| * This needs to be expanded to cover all the visible parts. |
| */ |
| static void mem_cgroup_css_reset(struct cgroup_subsys_state *css) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
| |
| page_counter_set_max(&memcg->memory, PAGE_COUNTER_MAX); |
| page_counter_set_max(&memcg->swap, PAGE_COUNTER_MAX); |
| page_counter_set_max(&memcg->kmem, PAGE_COUNTER_MAX); |
| page_counter_set_max(&memcg->tcpmem, PAGE_COUNTER_MAX); |
| page_counter_set_min(&memcg->memory, 0); |
| page_counter_set_low(&memcg->memory, 0); |
| page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX); |
| memcg->soft_limit = PAGE_COUNTER_MAX; |
| page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX); |
| memcg_wb_domain_size_changed(memcg); |
| } |
| |
| #ifdef CONFIG_MMU |
| /* Handlers for move charge at task migration. */ |
| static int mem_cgroup_do_precharge(unsigned long count) |
| { |
| int ret; |
| |
| /* Try a single bulk charge without reclaim first, kswapd may wake */ |
| ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_DIRECT_RECLAIM, count); |
| if (!ret) { |
| mc.precharge += count; |
| return ret; |
| } |
| |
| /* Try charges one by one with reclaim, but do not retry */ |
| while (count--) { |
| ret = try_charge(mc.to, GFP_KERNEL | __GFP_NORETRY, 1); |
| if (ret) |
| return ret; |
| mc.precharge++; |
| cond_resched(); |
| } |
| return 0; |
| } |
| |
| union mc_target { |
| struct page *page; |
| swp_entry_t ent; |
| }; |
| |
| enum mc_target_type { |
| MC_TARGET_NONE = 0, |
| MC_TARGET_PAGE, |
| MC_TARGET_SWAP, |
| MC_TARGET_DEVICE, |
| }; |
| |
| static struct page *mc_handle_present_pte(struct vm_area_struct *vma, |
| unsigned long addr, pte_t ptent) |
| { |
| struct page *page = vm_normal_page(vma, addr, ptent); |
| |
| if (!page || !page_mapped(page)) |
| return NULL; |
| if (PageAnon(page)) { |
| if (!(mc.flags & MOVE_ANON)) |
| return NULL; |
| } else { |
| if (!(mc.flags & MOVE_FILE)) |
| return NULL; |
| } |
| if (!get_page_unless_zero(page)) |
| return NULL; |
| |
| return page; |
| } |
| |
| #if defined(CONFIG_SWAP) || defined(CONFIG_DEVICE_PRIVATE) |
| static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, |
| pte_t ptent, swp_entry_t *entry) |
| { |
| struct page *page = NULL; |
| swp_entry_t ent = pte_to_swp_entry(ptent); |
| |
| if (!(mc.flags & MOVE_ANON)) |
| return NULL; |
| |
| /* |
| * Handle MEMORY_DEVICE_PRIVATE which are ZONE_DEVICE page belonging to |
| * a device and because they are not accessible by CPU they are store |
| * as special swap entry in the CPU page table. |
| */ |
| if (is_device_private_entry(ent)) { |
| page = device_private_entry_to_page(ent); |
| /* |
| * MEMORY_DEVICE_PRIVATE means ZONE_DEVICE page and which have |
| * a refcount of 1 when free (unlike normal page) |
| */ |
| if (!page_ref_add_unless(page, 1, 1)) |
| return NULL; |
| return page; |
| } |
| |
| if (non_swap_entry(ent)) |
| return NULL; |
| |
| /* |
| * Because lookup_swap_cache() updates some statistics counter, |
| * we call find_get_page() with swapper_space directly. |
| */ |
| page = find_get_page(swap_address_space(ent), swp_offset(ent)); |
| entry->val = ent.val; |
| |
| return page; |
| } |
| #else |
| static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, |
| pte_t ptent, swp_entry_t *entry) |
| { |
| return NULL; |
| } |
| #endif |
| |
| static struct page *mc_handle_file_pte(struct vm_area_struct *vma, |
| unsigned long addr, pte_t ptent, swp_entry_t *entry) |
| { |
| if (!vma->vm_file) /* anonymous vma */ |
| return NULL; |
| if (!(mc.flags & MOVE_FILE)) |
| return NULL; |
| |
| /* page is moved even if it's not RSS of this task(page-faulted). */ |
| /* shmem/tmpfs may report page out on swap: account for that too. */ |
| return find_get_incore_page(vma->vm_file->f_mapping, |
| linear_page_index(vma, addr)); |
| } |
| |
| /** |
| * mem_cgroup_move_account - move account of the page |
| * @page: the page |
| * @compound: charge the page as compound or small page |
| * @from: mem_cgroup which the page is moved from. |
| * @to: mem_cgroup which the page is moved to. @from != @to. |
| * |
| * The caller must make sure the page is not on LRU (isolate_page() is useful.) |
| * |
| * This function doesn't do "charge" to new cgroup and doesn't do "uncharge" |
| * from old cgroup. |
| */ |
| static int mem_cgroup_move_account(struct page *page, |
| bool compound, |
| struct mem_cgroup *from, |
| struct mem_cgroup *to) |
| { |
| struct lruvec *from_vec, *to_vec; |
| struct pglist_data *pgdat; |
| unsigned int nr_pages = compound ? thp_nr_pages(page) : 1; |
| int ret; |
| |
| VM_BUG_ON(from == to); |
| VM_BUG_ON_PAGE(PageLRU(page), page); |
| VM_BUG_ON(compound && !PageTransHuge(page)); |
| |
| /* |
| * Prevent mem_cgroup_migrate() from looking at |
| * page's memory cgroup of its source page while we change it. |
| */ |
| ret = -EBUSY; |
| if (!trylock_page(page)) |
| goto out; |
| |
| ret = -EINVAL; |
| if (page_memcg(page) != from) |
| goto out_unlock; |
| |
| pgdat = page_pgdat(page); |
| from_vec = mem_cgroup_lruvec(from, pgdat); |
| to_vec = mem_cgroup_lruvec(to, pgdat); |
| |
| lock_page_memcg(page); |
| |
| if (PageAnon(page)) { |
| if (page_mapped(page)) { |
| __mod_lruvec_state(from_vec, NR_ANON_MAPPED, -nr_pages); |
| __mod_lruvec_state(to_vec, NR_ANON_MAPPED, nr_pages); |
| if (PageTransHuge(page)) { |
| __mod_lruvec_state(from_vec, NR_ANON_THPS, |
| -nr_pages); |
| __mod_lruvec_state(to_vec, NR_ANON_THPS, |
| nr_pages); |
| } |
| |
| } |
| } else { |
| __mod_lruvec_state(from_vec, NR_FILE_PAGES, -nr_pages); |
| __mod_lruvec_state(to_vec, NR_FILE_PAGES, nr_pages); |
| |
| if (PageSwapBacked(page)) { |
| __mod_lruvec_state(from_vec, NR_SHMEM, -nr_pages); |
| __mod_lruvec_state(to_vec, NR_SHMEM, nr_pages); |
| } |
| |
| if (page_mapped(page)) { |
| __mod_lruvec_state(from_vec, NR_FILE_MAPPED, -nr_pages); |
| __mod_lruvec_state(to_vec, NR_FILE_MAPPED, nr_pages); |
| } |
| |
| if (PageDirty(page)) { |
| struct address_space *mapping = page_mapping(page); |
| |
| if (mapping_can_writeback(mapping)) { |
| __mod_lruvec_state(from_vec, NR_FILE_DIRTY, |
| -nr_pages); |
| __mod_lruvec_state(to_vec, NR_FILE_DIRTY, |
| nr_pages); |
| } |
| } |
| } |
| |
| if (PageWriteback(page)) { |
| __mod_lruvec_state(from_vec, NR_WRITEBACK, -nr_pages); |
| __mod_lruvec_state(to_vec, NR_WRITEBACK, nr_pages); |
| } |
| |
| /* |
| * All state has been migrated, let's switch to the new memcg. |
| * |
| * It is safe to change page's memcg here because the page |
| * is referenced, charged, isolated, and locked: we can't race |
| * with (un)charging, migration, LRU putback, or anything else |
| * that would rely on a stable page's memory cgroup. |
| * |
| * Note that lock_page_memcg is a memcg lock, not a page lock, |
| * to save space. As soon as we switch page's memory cgroup to a |
| * new memcg that isn't locked, the above state can change |
| * concurrently again. Make sure we're truly done with it. |
| */ |
| smp_mb(); |
| |
| css_get(&to->css); |
| css_put(&from->css); |
| |
| page->memcg_data = (unsigned long)to; |
| |
| __unlock_page_memcg(from); |
| |
| ret = 0; |
| |
| local_irq_disable(); |
| mem_cgroup_charge_statistics(to, page, nr_pages); |
| memcg_check_events(to, page); |
| mem_cgroup_charge_statistics(from, page, -nr_pages); |
| memcg_check_events(from, page); |
| local_irq_enable(); |
| out_unlock: |
| unlock_page(page); |
| out: |
| return ret; |
| } |
| |
| /** |
| * get_mctgt_type - get target type of moving charge |
| * @vma: the vma the pte to be checked belongs |
| * @addr: the address corresponding to the pte to be checked |
| * @ptent: the pte to be checked |
| * @target: the pointer the target page or swap ent will be stored(can be NULL) |
| * |
| * Returns |
| * 0(MC_TARGET_NONE): if the pte is not a target for move charge. |
| * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for |
| * move charge. if @target is not NULL, the page is stored in target->page |
| * with extra refcnt got(Callers should handle it). |
| * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a |
| * target for charge migration. if @target is not NULL, the entry is stored |
| * in target->ent. |
| * 3(MC_TARGET_DEVICE): like MC_TARGET_PAGE but page is MEMORY_DEVICE_PRIVATE |
| * (so ZONE_DEVICE page and thus not on the lru). |
| * For now we such page is charge like a regular page would be as for all |
| * intent and purposes it is just special memory taking the place of a |
| * regular page. |
| * |
| * See Documentations/vm/hmm.txt and include/linux/hmm.h |
| * |
| * Called with pte lock held. |
| */ |
| |
| static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma, |
| unsigned long addr, pte_t ptent, union mc_target *target) |
| { |
| struct page *page = NULL; |
| enum mc_target_type ret = MC_TARGET_NONE; |
| swp_entry_t ent = { .val = 0 }; |
| |
| if (pte_present(ptent)) |
| page = mc_handle_present_pte(vma, addr, ptent); |
| else if (is_swap_pte(ptent)) |
| page = mc_handle_swap_pte(vma, ptent, &ent); |
| else if (pte_none(ptent)) |
| page = mc_handle_file_pte(vma, addr, ptent, &ent); |
| |
| if (!page && !ent.val) |
| return ret; |
| if (page) { |
| /* |
| * Do only loose check w/o serialization. |
| * mem_cgroup_move_account() checks the page is valid or |
| * not under LRU exclusion. |
| */ |
| if (page_memcg(page) == mc.from) { |
| ret = MC_TARGET_PAGE; |
| if (is_device_private_page(page)) |
| ret = MC_TARGET_DEVICE; |
| if (target) |
| target->page = page; |
| } |
| if (!ret || !target) |
| put_page(page); |
| } |
| /* |
| * There is a swap entry and a page doesn't exist or isn't charged. |
| * But we cannot move a tail-page in a THP. |
| */ |
| if (ent.val && !ret && (!page || !PageTransCompound(page)) && |
| mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) { |
| ret = MC_TARGET_SWAP; |
| if (target) |
| target->ent = ent; |
| } |
| return ret; |
| } |
| |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| /* |
| * We don't consider PMD mapped swapping or file mapped pages because THP does |
| * not support them for now. |
| * Caller should make sure that pmd_trans_huge(pmd) is true. |
| */ |
| static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma, |
| unsigned long addr, pmd_t pmd, union mc_target *target) |
| { |
| struct page *page = NULL; |
| enum mc_target_type ret = MC_TARGET_NONE; |
| |
| if (unlikely(is_swap_pmd(pmd))) { |
| VM_BUG_ON(thp_migration_supported() && |
| !is_pmd_migration_entry(pmd)); |
| return ret; |
| } |
| page = pmd_page(pmd); |
| VM_BUG_ON_PAGE(!page || !PageHead(page), page); |
| if (!(mc.flags & MOVE_ANON)) |
| return ret; |
| if (page_memcg(page) == mc.from) { |
| ret = MC_TARGET_PAGE; |
| if (target) { |
| get_page(page); |
| target->page = page; |
| } |
| } |
| return ret; |
| } |
| #else |
| static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma, |
| unsigned long addr, pmd_t pmd, union mc_target *target) |
| { |
| return MC_TARGET_NONE; |
| } |
| #endif |
| |
| static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, |
| unsigned long addr, unsigned long end, |
| struct mm_walk *walk) |
| { |
| struct vm_area_struct *vma = walk->vma; |
| pte_t *pte; |
| spinlock_t *ptl; |
| |
| ptl = pmd_trans_huge_lock(pmd, vma); |
| if (ptl) { |
| /* |
| * Note their can not be MC_TARGET_DEVICE for now as we do not |
| * support transparent huge page with MEMORY_DEVICE_PRIVATE but |
| * this might change. |
| */ |
| if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE) |
| mc.precharge += HPAGE_PMD_NR; |
| spin_unlock(ptl); |
| return 0; |
| } |
| |
| if (pmd_trans_unstable(pmd)) |
| return 0; |
| pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); |
| for (; addr != end; pte++, addr += PAGE_SIZE) |
| if (get_mctgt_type(vma, addr, *pte, NULL)) |
| mc.precharge++; /* increment precharge temporarily */ |
| pte_unmap_unlock(pte - 1, ptl); |
| cond_resched(); |
| |
| return 0; |
| } |
| |
| static const struct mm_walk_ops precharge_walk_ops = { |
| .pmd_entry = mem_cgroup_count_precharge_pte_range, |
| }; |
| |
| static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm) |
| { |
| unsigned long precharge; |
| |
| mmap_read_lock(mm); |
| walk_page_range(mm, 0, mm->highest_vm_end, &precharge_walk_ops, NULL); |
| mmap_read_unlock(mm); |
| |
| precharge = mc.precharge; |
| mc.precharge = 0; |
| |
| return precharge; |
| } |
| |
| static int mem_cgroup_precharge_mc(struct mm_struct *mm) |
| { |
| unsigned long precharge = mem_cgroup_count_precharge(mm); |
| |
| VM_BUG_ON(mc.moving_task); |
| mc.moving_task = current; |
| return mem_cgroup_do_precharge(precharge); |
| } |
| |
| /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */ |
| static void __mem_cgroup_clear_mc(void) |
| { |
| struct mem_cgroup *from = mc.from; |
| struct mem_cgroup *to = mc.to; |
| |
| /* we must uncharge all the leftover precharges from mc.to */ |
| if (mc.precharge) { |
| cancel_charge(mc.to, mc.precharge); |
| mc.precharge = 0; |
| } |
| /* |
| * we didn't uncharge from mc.from at mem_cgroup_move_account(), so |
| * we must uncharge here. |
| */ |
| if (mc.moved_charge) { |
| cancel_charge(mc.from, mc.moved_charge); |
| mc.moved_charge = 0; |
| } |
| /* we must fixup refcnts and charges */ |
| if (mc.moved_swap) { |
| /* uncharge swap account from the old cgroup */ |
| if (!mem_cgroup_is_root(mc.from)) |
| page_counter_uncharge(&mc.from->memsw, mc.moved_swap); |
| |
| mem_cgroup_id_put_many(mc.from, mc.moved_swap); |
| |
| /* |
| * we charged both to->memory and to->memsw, so we |
| * should uncharge to->memory. |
| */ |
| if (!mem_cgroup_is_root(mc.to)) |
| page_counter_uncharge(&mc.to->memory, mc.moved_swap); |
| |
| mc.moved_swap = 0; |
| } |
| memcg_oom_recover(from); |
| memcg_oom_recover(to); |
| wake_up_all(&mc.waitq); |
| } |
| |
| static void mem_cgroup_clear_mc(void) |
| { |
| struct mm_struct *mm = mc.mm; |
| |
| /* |
| * we must clear moving_task before waking up waiters at the end of |
| * task migration. |
| */ |
| mc.moving_task = NULL; |
| __mem_cgroup_clear_mc(); |
| spin_lock(&mc.lock); |
| mc.from = NULL; |
| mc.to = NULL; |
| mc.mm = NULL; |
| spin_unlock(&mc.lock); |
| |
| mmput(mm); |
| } |
| |
| static int mem_cgroup_can_attach(struct cgroup_taskset *tset) |
| { |
| struct cgroup_subsys_state *css; |
| struct mem_cgroup *memcg = NULL; /* unneeded init to make gcc happy */ |
| struct mem_cgroup *from; |
| struct task_struct *leader, *p; |
| struct mm_struct *mm; |
| unsigned long move_flags; |
| int ret = 0; |
| |
| /* charge immigration isn't supported on the default hierarchy */ |
| if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) |
| return 0; |
| |
| /* |
| * Multi-process migrations only happen on the default hierarchy |
| * where charge immigration is not used. Perform charge |
| * immigration if @tset contains a leader and whine if there are |
| * multiple. |
| */ |
| p = NULL; |
| cgroup_taskset_for_each_leader(leader, css, tset) { |
| WARN_ON_ONCE(p); |
| p = leader; |
| memcg = mem_cgroup_from_css(css); |
| } |
| if (!p) |
| return 0; |
| |
| /* |
| * We are now commited to this value whatever it is. Changes in this |
| * tunable will only affect upcoming migrations, not the current one. |
| * So we need to save it, and keep it going. |
| */ |
| move_flags = READ_ONCE(memcg->move_charge_at_immigrate); |
| if (!move_flags) |
| return 0; |
| |
| from = mem_cgroup_from_task(p); |
| |
| VM_BUG_ON(from == memcg); |
| |
| mm = get_task_mm(p); |
| if (!mm) |
| return 0; |
| /* We move charges only when we move a owner of the mm */ |
| if (mm->owner == p) { |
| VM_BUG_ON(mc.from); |
| VM_BUG_ON(mc.to); |
| VM_BUG_ON(mc.precharge); |
| VM_BUG_ON(mc.moved_charge); |
| VM_BUG_ON(mc.moved_swap); |
| |
| spin_lock(&mc.lock); |
| mc.mm = mm; |
| mc.from = from; |
| mc.to = memcg; |
| mc.flags = move_flags; |
| spin_unlock(&mc.lock); |
| /* We set mc.moving_task later */ |
| |
| ret = mem_cgroup_precharge_mc(mm); |
| if (ret) |
| mem_cgroup_clear_mc(); |
| } else { |
| mmput(mm); |
| } |
| return ret; |
| } |
| |
| static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset) |
| { |
| if (mc.to) |
| mem_cgroup_clear_mc(); |
| } |
| |
| static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, |
| unsigned long addr, unsigned long end, |
| struct mm_walk *walk) |
| { |
| int ret = 0; |
| struct vm_area_struct *vma = walk->vma; |
| pte_t *pte; |
| spinlock_t *ptl; |
| enum mc_target_type target_type; |
| union mc_target target; |
| struct page *page; |
| |
| ptl = pmd_trans_huge_lock(pmd, vma); |
| if (ptl) { |
| if (mc.precharge < HPAGE_PMD_NR) { |
| spin_unlock(ptl); |
| return 0; |
| } |
| target_type = get_mctgt_type_thp(vma, addr, *pmd, &target); |
| if (target_type == MC_TARGET_PAGE) { |
| page = target.page; |
| if (!isolate_lru_page(page)) { |
| if (!mem_cgroup_move_account(page, true, |
| mc.from, mc.to)) { |
| mc.precharge -= HPAGE_PMD_NR; |
| mc.moved_charge += HPAGE_PMD_NR; |
| } |
| putback_lru_page(page); |
| } |
| put_page(page); |
| } else if (target_type == MC_TARGET_DEVICE) { |
| page = target.page; |
| if (!mem_cgroup_move_account(page, true, |
| mc.from, mc.to)) { |
| mc.precharge -= HPAGE_PMD_NR; |
| mc.moved_charge += HPAGE_PMD_NR; |
| } |
| put_page(page); |
| } |
| spin_unlock(ptl); |
| return 0; |
| } |
| |
| if (pmd_trans_unstable(pmd)) |
| return 0; |
| retry: |
| pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); |
| for (; addr != end; addr += PAGE_SIZE) { |
| pte_t ptent = *(pte++); |
| bool device = false; |
| swp_entry_t ent; |
| |
| if (!mc.precharge) |
| break; |
| |
| switch (get_mctgt_type(vma, addr, ptent, &target)) { |
| case MC_TARGET_DEVICE: |
| device = true; |
| fallthrough; |
| case MC_TARGET_PAGE: |
| page = target.page; |
| /* |
| * We can have a part of the split pmd here. Moving it |
| * can be done but it would be too convoluted so simply |
| * ignore such a partial THP and keep it in original |
| * memcg. There should be somebody mapping the head. |
| */ |
| if (PageTransCompound(page)) |
| goto put; |
| if (!device && isolate_lru_page(page)) |
| goto put; |
| if (!mem_cgroup_move_account(page, false, |
| mc.from, mc.to)) { |
| mc.precharge--; |
| /* we uncharge from mc.from later. */ |
| mc.moved_charge++; |
| } |
| if (!device) |
| putback_lru_page(page); |
| put: /* get_mctgt_type() gets the page */ |
| put_page(page); |
| break; |
| case MC_TARGET_SWAP: |
| ent = target.ent; |
| if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) { |
| mc.precharge--; |
| mem_cgroup_id_get_many(mc.to, 1); |
| /* we fixup other refcnts and charges later. */ |
| mc.moved_swap++; |
| } |
| break; |
| default: |
| break; |
| } |
| } |
| pte_unmap_unlock(pte - 1, ptl); |
| cond_resched(); |
| |
| if (addr != end) { |
| /* |
| * We have consumed all precharges we got in can_attach(). |
| * We try charge one by one, but don't do any additional |
| * charges to mc.to if we have failed in charge once in attach() |
| * phase. |
| */ |
| ret = mem_cgroup_do_precharge(1); |
| if (!ret) |
| goto retry; |
| } |
| |
| return ret; |
| } |
| |
| static const struct mm_walk_ops charge_walk_ops = { |
| .pmd_entry = mem_cgroup_move_charge_pte_range, |
| }; |
| |
| static void mem_cgroup_move_charge(void) |
| { |
| lru_add_drain_all(); |
| /* |
| * Signal lock_page_memcg() to take the memcg's move_lock |
| * while we're moving its pages to another memcg. Then wait |
| * for already started RCU-only updates to finish. |
| */ |
| atomic_inc(&mc.from->moving_account); |
| synchronize_rcu(); |
| retry: |
| if (unlikely(!mmap_read_trylock(mc.mm))) { |
| /* |
| * Someone who are holding the mmap_lock might be waiting in |
| * waitq. So we cancel all extra charges, wake up all waiters, |
| * and retry. Because we cancel precharges, we might not be able |
| * to move enough charges, but moving charge is a best-effort |
| * feature anyway, so it wouldn't be a big problem. |
| */ |
| __mem_cgroup_clear_mc(); |
| cond_resched(); |
| goto retry; |
| } |
| /* |
| * When we have consumed all precharges and failed in doing |
| * additional charge, the page walk just aborts. |
| */ |
| walk_page_range(mc.mm, 0, mc.mm->highest_vm_end, &charge_walk_ops, |
| NULL); |
| |
| mmap_read_unlock(mc.mm); |
| atomic_dec(&mc.from->moving_account); |
| } |
| |
| static void mem_cgroup_move_task(void) |
| { |
| if (mc.to) { |
| mem_cgroup_move_charge(); |
| mem_cgroup_clear_mc(); |
| } |
| } |
| #else /* !CONFIG_MMU */ |
| static int mem_cgroup_can_attach(struct cgroup_taskset *tset) |
| { |
| return 0; |
| } |
| static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset) |
| { |
| } |
| static void mem_cgroup_move_task(void) |
| { |
| } |
| #endif |
| |
| static int seq_puts_memcg_tunable(struct seq_file *m, unsigned long value) |
| { |
| if (value == PAGE_COUNTER_MAX) |
| seq_puts(m, "max\n"); |
| else |
| seq_printf(m, "%llu\n", (u64)value * PAGE_SIZE); |
| |
| return 0; |
| } |
| |
| static u64 memory_current_read(struct cgroup_subsys_state *css, |
| struct cftype *cft) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
| |
| return (u64)page_counter_read(&memcg->memory) * PAGE_SIZE; |
| } |
| |
| static int memory_min_show(struct seq_file *m, void *v) |
| { |
| return seq_puts_memcg_tunable(m, |
| READ_ONCE(mem_cgroup_from_seq(m)->memory.min)); |
| } |
| |
| static ssize_t memory_min_write(struct kernfs_open_file *of, |
| char *buf, size_t nbytes, loff_t off) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); |
| unsigned long min; |
| int err; |
| |
| buf = strstrip(buf); |
| err = page_counter_memparse(buf, "max", &min); |
| if (err) |
| return err; |
| |
| page_counter_set_min(&memcg->memory, min); |
| |
| return nbytes; |
| } |
| |
| static int memory_low_show(struct seq_file *m, void *v) |
| { |
| return seq_puts_memcg_tunable(m, |
| READ_ONCE(mem_cgroup_from_seq(m)->memory.low)); |
| } |
| |
| static ssize_t memory_low_write(struct kernfs_open_file *of, |
| char *buf, size_t nbytes, loff_t off) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); |
| unsigned long low; |
| int err; |
| |
| buf = strstrip(buf); |
| err = page_counter_memparse(buf, "max", &low); |
| if (err) |
| return err; |
| |
| page_counter_set_low(&memcg->memory, low); |
| |
| return nbytes; |
| } |
| |
| static int memory_high_show(struct seq_file *m, void *v) |
| { |
| return seq_puts_memcg_tunable(m, |
| READ_ONCE(mem_cgroup_from_seq(m)->memory.high)); |
| } |
| |
| static ssize_t memory_high_write(struct kernfs_open_file *of, |
| char *buf, size_t nbytes, loff_t off) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); |
| unsigned int nr_retries = MAX_RECLAIM_RETRIES; |
| bool drained = false; |
| unsigned long high; |
| int err; |
| |
| buf = strstrip(buf); |
| err = page_counter_memparse(buf, "max", &high); |
| if (err) |
| return err; |
| |
| for (;;) { |
| unsigned long nr_pages = page_counter_read(&memcg->memory); |
| unsigned long reclaimed; |
| |
| if (nr_pages <= high) |
| break; |
| |
| if (signal_pending(current)) |
| break; |
| |
| if (!drained) { |
| drain_all_stock(memcg); |
| drained = true; |
| continue; |
| } |
| |
| reclaimed = try_to_free_mem_cgroup_pages(memcg, nr_pages - high, |
| GFP_KERNEL, true); |
| |
| if (!reclaimed && !nr_retries--) |
| break; |
| } |
| |
| page_counter_set_high(&memcg->memory, high); |
| |
| memcg_wb_domain_size_changed(memcg); |
| |
| return nbytes; |
| } |
| |
| static int memory_max_show(struct seq_file *m, void *v) |
| { |
| return seq_puts_memcg_tunable(m, |
| READ_ONCE(mem_cgroup_from_seq(m)->memory.max)); |
| } |
| |
| static ssize_t memory_max_write(struct kernfs_open_file *of, |
| char *buf, size_t nbytes, loff_t off) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); |
| unsigned int nr_reclaims = MAX_RECLAIM_RETRIES; |
| bool drained = false; |
| unsigned long max; |
| int err; |
| |
| buf = strstrip(buf); |
| err = page_counter_memparse(buf, "max", &max); |
| if (err) |
| return err; |
| |
| xchg(&memcg->memory.max, max); |
| |
| for (;;) { |
| unsigned long nr_pages = page_counter_read(&memcg->memory); |
| |
| if (nr_pages <= max) |
| break; |
| |
| if (signal_pending(current)) |
| break; |
| |
| if (!drained) { |
| drain_all_stock(memcg); |
| drained = true; |
| continue; |
| } |
| |
| if (nr_reclaims) { |
| if (!try_to_free_mem_cgroup_pages(memcg, nr_pages - max, |
| GFP_KERNEL, true)) |
| nr_reclaims--; |
| continue; |
| } |
| |
| memcg_memory_event(memcg, MEMCG_OOM); |
| if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0)) |
| break; |
| } |
| |
| memcg_wb_domain_size_changed(memcg); |
| return nbytes; |
| } |
| |
| static void __memory_events_show(struct seq_file *m, atomic_long_t *events) |
| { |
| seq_printf(m, "low %lu\n", atomic_long_read(&events[MEMCG_LOW])); |
| seq_printf(m, "high %lu\n", atomic_long_read(&events[MEMCG_HIGH])); |
| seq_printf(m, "max %lu\n", atomic_long_read(&events[MEMCG_MAX])); |
| seq_printf(m, "oom %lu\n", atomic_long_read(&events[MEMCG_OOM])); |
| seq_printf(m, "oom_kill %lu\n", |
| atomic_long_read(&events[MEMCG_OOM_KILL])); |
| } |
| |
| static int memory_events_show(struct seq_file *m, void *v) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_seq(m); |
| |
| __memory_events_show(m, memcg->memory_events); |
| return 0; |
| } |
| |
| static int memory_events_local_show(struct seq_file *m, void *v) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_seq(m); |
| |
| __memory_events_show(m, memcg->memory_events_local); |
| return 0; |
| } |
| |
| static int memory_stat_show(struct seq_file *m, void *v) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_seq(m); |
| char *buf; |
| |
| buf = memory_stat_format(memcg); |
| if (!buf) |
| return -ENOMEM; |
| seq_puts(m, buf); |
| kfree(buf); |
| return 0; |
| } |
| |
| #ifdef CONFIG_NUMA |
| static int memory_numa_stat_show(struct seq_file *m, void *v) |
| { |
| int i; |
| struct mem_cgroup *memcg = mem_cgroup_from_seq(m); |
| |
| for (i = 0; i < ARRAY_SIZE(memory_stats); i++) { |
| int nid; |
| |
| if (memory_stats[i].idx >= NR_VM_NODE_STAT_ITEMS) |
| continue; |
| |
| seq_printf(m, "%s", memory_stats[i].name); |
| for_each_node_state(nid, N_MEMORY) { |
| u64 size; |
| struct lruvec *lruvec; |
| |
| lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid)); |
| size = lruvec_page_state(lruvec, memory_stats[i].idx); |
| size *= memory_stats[i].ratio; |
| seq_printf(m, " N%d=%llu", nid, size); |
| } |
| seq_putc(m, '\n'); |
| } |
| |
| return 0; |
| } |
| #endif |
| |
| static int memory_oom_group_show(struct seq_file *m, void *v) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_seq(m); |
| |
| seq_printf(m, "%d\n", memcg->oom_group); |
| |
| return 0; |
| } |
| |
| static ssize_t memory_oom_group_write(struct kernfs_open_file *of, |
| char *buf, size_t nbytes, loff_t off) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); |
| int ret, oom_group; |
| |
| buf = strstrip(buf); |
| if (!buf) |
| return -EINVAL; |
| |
| ret = kstrtoint(buf, 0, &oom_group); |
| if (ret) |
| return ret; |
| |
| if (oom_group != 0 && oom_group != 1) |
| return -EINVAL; |
| |
| memcg->oom_group = oom_group; |
| |
| return nbytes; |
| } |
| |
| static struct cftype memory_files[] = { |
| { |
| .name = "current", |
| .flags = CFTYPE_NOT_ON_ROOT, |
| .read_u64 = memory_current_read, |
| }, |
| { |
| .name = "min", |
| .flags = CFTYPE_NOT_ON_ROOT, |
| .seq_show = memory_min_show, |
| .write = memory_min_write, |
| }, |
| { |
| .name = "low", |
| .flags = CFTYPE_NOT_ON_ROOT, |
| .seq_show = memory_low_show, |
| .write = memory_low_write, |
| }, |
| { |
| .name = "high", |
| .flags = CFTYPE_NOT_ON_ROOT, |
| .seq_show = memory_high_show, |
| .write = memory_high_write, |
| }, |
| { |
| .name = "max", |
| .flags = CFTYPE_NOT_ON_ROOT, |
| .seq_show = memory_max_show, |
| .write = memory_max_write, |
| }, |
| { |
| .name = "events", |
| .flags = CFTYPE_NOT_ON_ROOT, |
| .file_offset = offsetof(struct mem_cgroup, events_file), |
| .seq_show = memory_events_show, |
| }, |
| { |
| .name = "events.local", |
| .flags = CFTYPE_NOT_ON_ROOT, |
| .file_offset = offsetof(struct mem_cgroup, events_local_file), |
| .seq_show = memory_events_local_show, |
| }, |
| { |
| .name = "stat", |
| .seq_show = memory_stat_show, |
| }, |
| #ifdef CONFIG_NUMA |
| { |
| .name = "numa_stat", |
| .seq_show = memory_numa_stat_show, |
| }, |
| #endif |
| { |
| .name = "oom.group", |
| .flags = CFTYPE_NOT_ON_ROOT | CFTYPE_NS_DELEGATABLE, |
| .seq_show = memory_oom_group_show, |
| .write = memory_oom_group_write, |
| }, |
| { } /* terminate */ |
| }; |
| |
| struct cgroup_subsys memory_cgrp_subsys = { |
| .css_alloc = mem_cgroup_css_alloc, |
| .css_online = mem_cgroup_css_online, |
| .css_offline = mem_cgroup_css_offline, |
| .css_released = mem_cgroup_css_released, |
| .css_free = mem_cgroup_css_free, |
| .css_reset = mem_cgroup_css_reset, |
| .can_attach = mem_cgroup_can_attach, |
| .cancel_attach = mem_cgroup_cancel_attach, |
| .post_attach = mem_cgroup_move_task, |
| .dfl_cftypes = memory_files, |
| .legacy_cftypes = mem_cgroup_legacy_files, |
| .early_init = 0, |
| }; |
| |
| /* |
| * This function calculates an individual cgroup's effective |
| * protection which is derived from its own memory.min/low, its |
| * parent's and siblings' settings, as well as the actual memory |
| * distribution in the tree. |
| * |
| * The following rules apply to the effective protection values: |
| * |
| * 1. At the first level of reclaim, effective protection is equal to |
| * the declared protection in memory.min and memory.low. |
| * |
| * 2. To enable safe delegation of the protection configuration, at |
| * subsequent levels the effective protection is capped to the |
| * parent's effective protection. |
| * |
| * 3. To make complex and dynamic subtrees easier to configure, the |
| * user is allowed to overcommit the declared protection at a given |
| * level. If that is the case, the parent's effective protection is |
| * distributed to the children in proportion to how much protection |
| * they have declared and how much of it they are utilizing. |
| * |
| * This makes distribution proportional, but also work-conserving: |
| * if one cgroup claims much more protection than it uses memory, |
| * the unused remainder is available to its siblings. |
| * |
| * 4. Conversely, when the declared protection is undercommitted at a |
| * given level, the distribution of the larger parental protection |
| * budget is NOT proportional. A cgroup's protection from a sibling |
| * is capped to its own memory.min/low setting. |
| * |
| * 5. However, to allow protecting recursive subtrees from each other |
| * without having to declare each individual cgroup's fixed share |
| * of the ancestor's claim to protection, any unutilized - |
| * "floating" - protection from up the tree is distributed in |
| * proportion to each cgroup's *usage*. This makes the protection |
| * neutral wrt sibling cgroups and lets them compete freely over |
| * the shared parental protection budget, but it protects the |
| * subtree as a whole from neighboring subtrees. |
| * |
| * Note that 4. and 5. are not in conflict: 4. is about protecting |
| * against immediate siblings whereas 5. is about protecting against |
| * neighboring subtrees. |
| */ |
| static unsigned long effective_protection(unsigned long usage, |
| unsigned long parent_usage, |
| unsigned long setting, |
| unsigned long parent_effective, |
| unsigned long siblings_protected) |
| { |
| unsigned long protected; |
| unsigned long ep; |
| |
| protected = min(usage, setting); |
| /* |
| * If all cgroups at this level combined claim and use more |
| * protection then what the parent affords them, distribute |
| * shares in proportion to utilization. |
| * |
| * We are using actual utilization rather than the statically |
| * claimed protection in order to be work-conserving: claimed |
| * but unused protection is available to siblings that would |
| * otherwise get a smaller chunk than what they claimed. |
| */ |
| if (siblings_protected > parent_effective) |
| return protected * parent_effective / siblings_protected; |
| |
| /* |
| * Ok, utilized protection of all children is within what the |
| * parent affords them, so we know whatever this child claims |
| * and utilizes is effectively protected. |
| * |
| * If there is unprotected usage beyond this value, reclaim |
| * will apply pressure in proportion to that amount. |
| * |
| * If there is unutilized protection, the cgroup will be fully |
| * shielded from reclaim, but we do return a smaller value for |
| * protection than what the group could enjoy in theory. This |
| * is okay. With the overcommit distribution above, effective |
| * protection is always dependent on how memory is actually |
| * consumed among the siblings anyway. |
| */ |
| ep = protected; |
| |
| /* |
| * If the children aren't claiming (all of) the protection |
| * afforded to them by the parent, distribute the remainder in |
| * proportion to the (unprotected) memory of each cgroup. That |
| * way, cgroups that aren't explicitly prioritized wrt each |
| * other compete freely over the allowance, but they are |
| * collectively protected from neighboring trees. |
| * |
| * We're using unprotected memory for the weight so that if |
| * some cgroups DO claim explicit protection, we don't protect |
| * the same bytes twice. |
| * |
| * Check both usage and parent_usage against the respective |
| * protected values. One should imply the other, but they |
| * aren't read atomically - make sure the division is sane. |
| */ |
| if (!(cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_RECURSIVE_PROT)) |
| return ep; |
| if (parent_effective > siblings_protected && |
| parent_usage > siblings_protected && |
| usage > protected) { |
| unsigned long unclaimed; |
| |
| unclaimed = parent_effective - siblings_protected; |
| unclaimed *= usage - protected; |
| unclaimed /= parent_usage - siblings_protected; |
| |
| ep += unclaimed; |
| } |
| |
| return ep; |
| } |
| |
| /** |
| * mem_cgroup_protected - check if memory consumption is in the normal range |
| * @root: the top ancestor of the sub-tree being checked |
| * @memcg: the memory cgroup to check |
| * |
| * WARNING: This function is not stateless! It can only be used as part |
| * of a top-down tree iteration, not for isolated queries. |
| */ |
| void mem_cgroup_calculate_protection(struct mem_cgroup *root, |
| struct mem_cgroup *memcg) |
| { |
| unsigned long usage, parent_usage; |
| struct mem_cgroup *parent; |
| |
| if (mem_cgroup_disabled()) |
| return; |
| |
| if (!root) |
| root = root_mem_cgroup; |
| |
| /* |
| * Effective values of the reclaim targets are ignored so they |
| * can be stale. Have a look at mem_cgroup_protection for more |
| * details. |
| * TODO: calculation should be more robust so that we do not need |
| * that special casing. |
| */ |
| if (memcg == root) |
| return; |
| |
| usage = page_counter_read(&memcg->memory); |
| if (!usage) |
| return; |
| |
| parent = parent_mem_cgroup(memcg); |
| /* No parent means a non-hierarchical mode on v1 memcg */ |
| if (!parent) |
| return; |
| |
| if (parent == root) { |
| memcg->memory.emin = READ_ONCE(memcg->memory.min); |
| memcg->memory.elow = READ_ONCE(memcg->memory.low); |
| return; |
| } |
| |
| parent_usage = page_counter_read(&parent->memory); |
| |
| WRITE_ONCE(memcg->memory.emin, effective_protection(usage, parent_usage, |
| READ_ONCE(memcg->memory.min), |
| READ_ONCE(parent->memory.emin), |
| atomic_long_read(&parent->memory.children_min_usage))); |
| |
| WRITE_ONCE(memcg->memory.elow, effective_protection(usage, parent_usage, |
| READ_ONCE(memcg->memory.low), |
| READ_ONCE(parent->memory.elow), |
| atomic_long_read(&parent->memory.children_low_usage))); |
| } |
| |
| /** |
| * mem_cgroup_charge - charge a newly allocated page to a cgroup |
| * @page: page to charge |
| * @mm: mm context of the victim |
| * @gfp_mask: reclaim mode |
| * |
| * Try to charge @page to the memcg that @mm belongs to, reclaiming |
| * pages according to @gfp_mask if necessary. |
| * |
| * Returns 0 on success. Otherwise, an error code is returned. |
| */ |
| int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) |
| { |
| unsigned int nr_pages = thp_nr_pages(page); |
| struct mem_cgroup *memcg = NULL; |
| int ret = 0; |
| |
| if (mem_cgroup_disabled()) |
| goto out; |
| |
| if (PageSwapCache(page)) { |
| swp_entry_t ent = { .val = page_private(page), }; |
| unsigned short id; |
| |
| /* |
| * Every swap fault against a single page tries to charge the |
| * page, bail as early as possible. shmem_unuse() encounters |
| * already charged pages, too. page and memcg binding is |
| * protected by the page lock, which serializes swap cache |
| * removal, which in turn serializes uncharging. |
| */ |
| VM_BUG_ON_PAGE(!PageLocked(page), page); |
| if (page_memcg(compound_head(page))) |
| goto out; |
| |
| id = lookup_swap_cgroup_id(ent); |
| rcu_read_lock(); |
| memcg = mem_cgroup_from_id(id); |
| if (memcg && !css_tryget_online(&memcg->css)) |
| memcg = NULL; |
| rcu_read_unlock(); |
| } |
| |
| if (!memcg) |
| memcg = get_mem_cgroup_from_mm(mm); |
| |
| ret = try_charge(memcg, gfp_mask, nr_pages); |
| if (ret) |
| goto out_put; |
| |
| css_get(&memcg->css); |
| commit_charge(page, memcg); |
| |
| local_irq_disable(); |
| mem_cgroup_charge_statistics(memcg, page, nr_pages); |
| memcg_check_events(memcg, page); |
| local_irq_enable(); |
| |
| if (PageSwapCache(page)) { |
| swp_entry_t entry = { .val = page_private(page) }; |
| /* |
| * The swap entry might not get freed for a long time, |
| * let's not wait for it. The page already received a |
| * memory+swap charge, drop the swap entry duplicate. |
| */ |
| mem_cgroup_uncharge_swap(entry, nr_pages); |
| } |
| |
| out_put: |
| css_put(&memcg->css); |
| out: |
| return ret; |
| } |
| |
| struct uncharge_gather { |
| struct mem_cgroup *memcg; |
| unsigned long nr_pages; |
| unsigned long pgpgout; |
| unsigned long nr_kmem; |
| struct page *dummy_page; |
| }; |
| |
| static inline void uncharge_gather_clear(struct uncharge_gather *ug) |
| { |
| memset(ug, 0, sizeof(*ug)); |
| } |
| |
| static void uncharge_batch(const struct uncharge_gather *ug) |
| { |
| unsigned long flags; |
| |
| if (!mem_cgroup_is_root(ug->memcg)) { |
| page_counter_uncharge(&ug->memcg->memory, ug->nr_pages); |
| if (do_memsw_account()) |
| page_counter_uncharge(&ug->memcg->memsw, ug->nr_pages); |
| if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && ug->nr_kmem) |
| page_counter_uncharge(&ug->memcg->kmem, ug->nr_kmem); |
| memcg_oom_recover(ug->memcg); |
| } |
| |
| local_irq_save(flags); |
| __count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout); |
| __this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, ug->nr_pages); |
| memcg_check_events(ug->memcg, ug->dummy_page); |
| local_irq_restore(flags); |
| |
| /* drop reference from uncharge_page */ |
| css_put(&ug->memcg->css); |
| } |
| |
| static void uncharge_page(struct page *page, struct uncharge_gather *ug) |
| { |
| unsigned long nr_pages; |
| |
| VM_BUG_ON_PAGE(PageLRU(page), page); |
| |
| if (!page_memcg(page)) |
| return; |
| |
| /* |
| * Nobody should be changing or seriously looking at |
| * page_memcg(page) at this point, we have fully |
| * exclusive access to the page. |
| */ |
| |
| if (ug->memcg != page_memcg(page)) { |
| if (ug->memcg) { |
| uncharge_batch(ug); |
| uncharge_gather_clear(ug); |
| } |
| ug->memcg = page_memcg(page); |
| |
| /* pairs with css_put in uncharge_batch */ |
| css_get(&ug->memcg->css); |
| } |
| |
| nr_pages = compound_nr(page); |
| ug->nr_pages += nr_pages; |
| |
| if (PageMemcgKmem(page)) |
| ug->nr_kmem += nr_pages; |
| else |
| ug->pgpgout++; |
| |
| ug->dummy_page = page; |
| page->memcg_data = 0; |
| css_put(&ug->memcg->css); |
| } |
| |
| static void uncharge_list(struct list_head *page_list) |
| { |
| struct uncharge_gather ug; |
| struct list_head *next; |
| |
| uncharge_gather_clear(&ug); |
| |
| /* |
| * Note that the list can be a single page->lru; hence the |
| * do-while loop instead of a simple list_for_each_entry(). |
| */ |
| next = page_list->next; |
| do { |
| struct page *page; |
| |
| page = list_entry(next, struct page, lru); |
| next = page->lru.next; |
| |
| uncharge_page(page, &ug); |
| } while (next != page_list); |
| |
| if (ug.memcg) |
| uncharge_batch(&ug); |
| } |
| |
| /** |
| * mem_cgroup_uncharge - uncharge a page |
| * @page: page to uncharge |
| * |
| * Uncharge a page previously charged with mem_cgroup_charge(). |
| */ |
| void mem_cgroup_uncharge(struct page *page) |
| { |
| struct uncharge_gather ug; |
| |
| if (mem_cgroup_disabled()) |
| return; |
| |
| /* Don't touch page->lru of any random page, pre-check: */ |
| if (!page_memcg(page)) |
| return; |
| |
| uncharge_gather_clear(&ug); |
| uncharge_page(page, &ug); |
| uncharge_batch(&ug); |
| } |
| |
| /** |
| * mem_cgroup_uncharge_list - uncharge a list of page |
| * @page_list: list of pages to uncharge |
| * |
| * Uncharge a list of pages previously charged with |
| * mem_cgroup_charge(). |
| */ |
| void mem_cgroup_uncharge_list(struct list_head *page_list) |
| { |
| if (mem_cgroup_disabled()) |
| return; |
| |
| if (!list_empty(page_list)) |
| uncharge_list(page_list); |
| } |
| |
| /** |
| * mem_cgroup_migrate - charge a page's replacement |
| * @oldpage: currently circulating page |
| * @newpage: replacement page |
| * |
| * Charge @newpage as a replacement page for @oldpage. @oldpage will |
| * be uncharged upon free. |
| * |
| * Both pages must be locked, @newpage->mapping must be set up. |
| */ |
| void mem_cgroup_migrate(struct page *oldpage, struct page *newpage) |
| { |
| struct mem_cgroup *memcg; |
| unsigned int nr_pages; |
| unsigned long flags; |
| |
| VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage); |
| VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); |
| VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage); |
| VM_BUG_ON_PAGE(PageTransHuge(oldpage) != PageTransHuge(newpage), |
| newpage); |
| |
| if (mem_cgroup_disabled()) |
| return; |
| |
| /* Page cache replacement: new page already charged? */ |
| if (page_memcg(newpage)) |
| return; |
| |
| memcg = page_memcg(oldpage); |
| VM_WARN_ON_ONCE_PAGE(!memcg, oldpage); |
| if (!memcg) |
| return; |
| |
| /* Force-charge the new page. The old one will be freed soon */ |
| nr_pages = thp_nr_pages(newpage); |
| |
| page_counter_charge(&memcg->memory, nr_pages); |
| if (do_memsw_account()) |
| page_counter_charge(&memcg->memsw, nr_pages); |
| |
| css_get(&memcg->css); |
| commit_charge(newpage, memcg); |
| |
| local_irq_save(flags); |
| mem_cgroup_charge_statistics(memcg, newpage, nr_pages); |
| memcg_check_events(memcg, newpage); |
| local_irq_restore(flags); |
| } |
| |
| DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key); |
| EXPORT_SYMBOL(memcg_sockets_enabled_key); |
| |
| void mem_cgroup_sk_alloc(struct sock *sk) |
| { |
| struct mem_cgroup *memcg; |
| |
| if (!mem_cgroup_sockets_enabled) |
| return; |
| |
| /* Do not associate the sock with unrelated interrupted task's memcg. */ |
| if (in_interrupt()) |
| return; |
| |
| rcu_read_lock(); |
| memcg = mem_cgroup_from_task(current); |
| if (memcg == root_mem_cgroup) |
| goto out; |
| if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg->tcpmem_active) |
| goto out; |
| if (css_tryget(&memcg->css)) |
| sk->sk_memcg = memcg; |
| out: |
| rcu_read_unlock(); |
| } |
| |
| void mem_cgroup_sk_free(struct sock *sk) |
| { |
| if (sk->sk_memcg) |
| css_put(&sk->sk_memcg->css); |
| } |
| |
| /** |
| * mem_cgroup_charge_skmem - charge socket memory |
| * @memcg: memcg to charge |
| * @nr_pages: number of pages to charge |
| * |
| * Charges @nr_pages to @memcg. Returns %true if the charge fit within |
| * @memcg's configured limit, %false if the charge had to be forced. |
| */ |
| bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages) |
| { |
| gfp_t gfp_mask = GFP_KERNEL; |
| |
| if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) { |
| struct page_counter *fail; |
| |
| if (page_counter_try_charge(&memcg->tcpmem, nr_pages, &fail)) { |
| memcg->tcpmem_pressure = 0; |
| return true; |
| } |
| page_counter_charge(&memcg->tcpmem, nr_pages); |
| memcg->tcpmem_pressure = 1; |
| return false; |
| } |
| |
| /* Don't block in the packet receive path */ |
| if (in_softirq()) |
| gfp_mask = GFP_NOWAIT; |
| |
| mod_memcg_state(memcg, MEMCG_SOCK, nr_pages); |
| |
| if (try_charge(memcg, gfp_mask, nr_pages) == 0) |
| return true; |
| |
| try_charge(memcg, gfp_mask|__GFP_NOFAIL, nr_pages); |
| return false; |
| } |
| |
| /** |
| * mem_cgroup_uncharge_skmem - uncharge socket memory |
| * @memcg: memcg to uncharge |
| * @nr_pages: number of pages to uncharge |
| */ |
| void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages) |
| { |
| if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) { |
| page_counter_uncharge(&memcg->tcpmem, nr_pages); |
| return; |
| } |
| |
| mod_memcg_state(memcg, MEMCG_SOCK, -nr_pages); |
| |
| refill_stock(memcg, nr_pages); |
| } |
| |
| static int __init cgroup_memory(char *s) |
| { |
| char *token; |
| |
| while ((token = strsep(&s, ",")) != NULL) { |
| if (!*token) |
| continue; |
| if (!strcmp(token, "nosocket")) |
| cgroup_memory_nosocket = true; |
| if (!strcmp(token, "nokmem")) |
| cgroup_memory_nokmem = true; |
| } |
| return 0; |
| } |
| __setup("cgroup.memory=", cgroup_memory); |
| |
| /* |
| * subsys_initcall() for memory controller. |
| * |
| * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this |
| * context because of lock dependencies (cgroup_lock -> cpu hotplug) but |
| * basically everything that doesn't depend on a specific mem_cgroup structure |
| * should be initialized from here. |
| */ |
| static int __init mem_cgroup_init(void) |
| { |
| int cpu, node; |
| |
| cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL, |
| memcg_hotplug_cpu_dead); |
| |
| for_each_possible_cpu(cpu) |
| INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work, |
| drain_local_stock); |
| |
| for_each_node(node) { |
| struct mem_cgroup_tree_per_node *rtpn; |
| |
| rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, |
| node_online(node) ? node : NUMA_NO_NODE); |
| |
| rtpn->rb_root = RB_ROOT; |
| rtpn->rb_rightmost = NULL; |
| spin_lock_init(&rtpn->lock); |
| soft_limit_tree.rb_tree_per_node[node] = rtpn; |
| } |
| |
| return 0; |
| } |
| subsys_initcall(mem_cgroup_init); |
| |
| #ifdef CONFIG_MEMCG_SWAP |
| static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg) |
| { |
| while (!refcount_inc_not_zero(&memcg->id.ref)) { |
| /* |
| * The root cgroup cannot be destroyed, so it's refcount must |
| * always be >= 1. |
| */ |
| if (WARN_ON_ONCE(memcg == root_mem_cgroup)) { |
| VM_BUG_ON(1); |
| break; |
| } |
| memcg = parent_mem_cgroup(memcg); |
| if (!memcg) |
| memcg = root_mem_cgroup; |
| } |
| return memcg; |
| } |
| |
| /** |
| * mem_cgroup_swapout - transfer a memsw charge to swap |
| * @page: page whose memsw charge to transfer |
| * @entry: swap entry to move the charge to |
| * |
| * Transfer the memsw charge of @page to @entry. |
| */ |
| void mem_cgroup_swapout(struct page *page, swp_entry_t entry) |
| { |
| struct mem_cgroup *memcg, *swap_memcg; |
| unsigned int nr_entries; |
| unsigned short oldid; |
| |
| VM_BUG_ON_PAGE(PageLRU(page), page); |
| VM_BUG_ON_PAGE(page_count(page), page); |
| |
| if (mem_cgroup_disabled()) |
| return; |
| |
| if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) |
| return; |
| |
| memcg = page_memcg(page); |
| |
| VM_WARN_ON_ONCE_PAGE(!memcg, page); |
| if (!memcg) |
| return; |
| |
| /* |
| * In case the memcg owning these pages has been offlined and doesn't |
| * have an ID allocated to it anymore, charge the closest online |
| * ancestor for the swap instead and transfer the memory+swap charge. |
| */ |
| swap_memcg = mem_cgroup_id_get_online(memcg); |
| nr_entries = thp_nr_pages(page); |
| /* Get references for the tail pages, too */ |
| if (nr_entries > 1) |
| mem_cgroup_id_get_many(swap_memcg, nr_entries - 1); |
| oldid = swap_cgroup_record(entry, mem_cgroup_id(swap_memcg), |
| nr_entries); |
| VM_BUG_ON_PAGE(oldid, page); |
| mod_memcg_state(swap_memcg, MEMCG_SWAP, nr_entries); |
| |
| page->memcg_data = 0; |
| |
| if (!mem_cgroup_is_root(memcg)) |
| page_counter_uncharge(&memcg->memory, nr_entries); |
| |
| if (!cgroup_memory_noswap && memcg != swap_memcg) { |
| if (!mem_cgroup_is_root(swap_memcg)) |
| page_counter_charge(&swap_memcg->memsw, nr_entries); |
| page_counter_uncharge(&memcg->memsw, nr_entries); |
| } |
| |
| /* |
| * Interrupts should be disabled here because the caller holds the |
| * i_pages lock which is taken with interrupts-off. It is |
| * important here to have the interrupts disabled because it is the |
| * only synchronisation we have for updating the per-CPU variables. |
| */ |
| VM_BUG_ON(!irqs_disabled()); |
| mem_cgroup_charge_statistics(memcg, page, -nr_entries); |
| memcg_check_events(memcg, page); |
| |
| css_put(&memcg->css); |
| } |
| |
| /** |
| * mem_cgroup_try_charge_swap - try charging swap space for a page |
| * @page: page being added to swap |
| * @entry: swap entry to charge |
| * |
| * Try to charge @page's memcg for the swap space at @entry. |
| * |
| * Returns 0 on success, -ENOMEM on failure. |
| */ |
| int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry) |
| { |
| unsigned int nr_pages = thp_nr_pages(page); |
| struct page_counter *counter; |
| struct mem_cgroup *memcg; |
| unsigned short oldid; |
| |
| if (mem_cgroup_disabled()) |
| return 0; |
| |
| if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) |
| return 0; |
| |
| memcg = page_memcg(page); |
| |
| VM_WARN_ON_ONCE_PAGE(!memcg, page); |
| if (!memcg) |
| return 0; |
| |
| if (!entry.val) { |
| memcg_memory_event(memcg, MEMCG_SWAP_FAIL); |
| return 0; |
| } |
| |
| memcg = mem_cgroup_id_get_online(memcg); |
| |
| if (!cgroup_memory_noswap && !mem_cgroup_is_root(memcg) && |
| !page_counter_try_charge(&memcg->swap, nr_pages, &counter)) { |
| memcg_memory_event(memcg, MEMCG_SWAP_MAX); |
| memcg_memory_event(memcg, MEMCG_SWAP_FAIL); |
| mem_cgroup_id_put(memcg); |
| return -ENOMEM; |
| } |
| |
| /* Get references for the tail pages, too */ |
| if (nr_pages > 1) |
| mem_cgroup_id_get_many(memcg, nr_pages - 1); |
| oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg), nr_pages); |
| VM_BUG_ON_PAGE(oldid, page); |
| mod_memcg_state(memcg, MEMCG_SWAP, nr_pages); |
| |
| return 0; |
| } |
| |
| /** |
| * mem_cgroup_uncharge_swap - uncharge swap space |
| * @entry: swap entry to uncharge |
| * @nr_pages: the amount of swap space to uncharge |
| */ |
| void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages) |
| { |
| struct mem_cgroup *memcg; |
| unsigned short id; |
| |
| id = swap_cgroup_record(entry, 0, nr_pages); |
| rcu_read_lock(); |
| memcg = mem_cgroup_from_id(id); |
| if (memcg) { |
| if (!cgroup_memory_noswap && !mem_cgroup_is_root(memcg)) { |
| if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) |
| page_counter_uncharge(&memcg->swap, nr_pages); |
| else |
| page_counter_uncharge(&memcg->memsw, nr_pages); |
| } |
| mod_memcg_state(memcg, MEMCG_SWAP, -nr_pages); |
| mem_cgroup_id_put_many(memcg, nr_pages); |
| } |
| rcu_read_unlock(); |
| } |
| |
| long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) |
| { |
| long nr_swap_pages = get_nr_swap_pages(); |
| |
| if (cgroup_memory_noswap || !cgroup_subsys_on_dfl(memory_cgrp_subsys)) |
| return nr_swap_pages; |
| for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) |
| nr_swap_pages = min_t(long, nr_swap_pages, |
| READ_ONCE(memcg->swap.max) - |
| page_counter_read(&memcg->swap)); |
| return nr_swap_pages; |
| } |
| |
| bool mem_cgroup_swap_full(struct page *page) |
| { |
| struct mem_cgroup *memcg; |
| |
| VM_BUG_ON_PAGE(!PageLocked(page), page); |
| |
| if (vm_swap_full()) |
| return true; |
| if (cgroup_memory_noswap || !cgroup_subsys_on_dfl(memory_cgrp_subsys)) |
| return false; |
| |
| memcg = page_memcg(page); |
| if (!memcg) |
| return false; |
| |
| for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) { |
| unsigned long usage = page_counter_read(&memcg->swap); |
| |
| if (usage * 2 >= READ_ONCE(memcg->swap.high) || |
| usage * 2 >= READ_ONCE(memcg->swap.max)) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| static int __init setup_swap_account(char *s) |
| { |
| if (!strcmp(s, "1")) |
| cgroup_memory_noswap = false; |
| else if (!strcmp(s, "0")) |
| cgroup_memory_noswap = true; |
| return 1; |
| } |
| __setup("swapaccount=", setup_swap_account); |
| |
| static u64 swap_current_read(struct cgroup_subsys_state *css, |
| struct cftype *cft) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(css); |
| |
| return (u64)page_counter_read(&memcg->swap) * PAGE_SIZE; |
| } |
| |
| static int swap_high_show(struct seq_file *m, void *v) |
| { |
| return seq_puts_memcg_tunable(m, |
| READ_ONCE(mem_cgroup_from_seq(m)->swap.high)); |
| } |
| |
| static ssize_t swap_high_write(struct kernfs_open_file *of, |
| char *buf, size_t nbytes, loff_t off) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); |
| unsigned long high; |
| int err; |
| |
| buf = strstrip(buf); |
| err = page_counter_memparse(buf, "max", &high); |
| if (err) |
| return err; |
| |
| page_counter_set_high(&memcg->swap, high); |
| |
| return nbytes; |
| } |
| |
| static int swap_max_show(struct seq_file *m, void *v) |
| { |
| return seq_puts_memcg_tunable(m, |
| READ_ONCE(mem_cgroup_from_seq(m)->swap.max)); |
| } |
| |
| static ssize_t swap_max_write(struct kernfs_open_file *of, |
| char *buf, size_t nbytes, loff_t off) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); |
| unsigned long max; |
| int err; |
| |
| buf = strstrip(buf); |
| err = page_counter_memparse(buf, "max", &max); |
| if (err) |
| return err; |
| |
| xchg(&memcg->swap.max, max); |
| |
| return nbytes; |
| } |
| |
| static int swap_events_show(struct seq_file *m, void *v) |
| { |
| struct mem_cgroup *memcg = mem_cgroup_from_seq(m); |
| |
| seq_printf(m, "high %lu\n", |
| atomic_long_read(&memcg->memory_events[MEMCG_SWAP_HIGH])); |
| seq_printf(m, "max %lu\n", |
| atomic_long_read(&memcg->memory_events[MEMCG_SWAP_MAX])); |
| seq_printf(m, "fail %lu\n", |
| atomic_long_read(&memcg->memory_events[MEMCG_SWAP_FAIL])); |
| |
| return 0; |
| } |
| |
| static struct cftype swap_files[] = { |
| { |
| .name = "swap.current", |
| .flags = CFTYPE_NOT_ON_ROOT, |
| .read_u64 = swap_current_read, |
| }, |
| { |
| .name = "swap.high", |
| .flags = CFTYPE_NOT_ON_ROOT, |
| .seq_show = swap_high_show, |
| .write = swap_high_write, |
| }, |
| { |
| .name = "swap.max", |
| .flags = CFTYPE_NOT_ON_ROOT, |
| .seq_show = swap_max_show, |
| .write = swap_max_write, |
| }, |
| { |
| .name = "swap.events", |
| .flags = CFTYPE_NOT_ON_ROOT, |
| .file_offset = offsetof(struct mem_cgroup, swap_events_file), |
| .seq_show = swap_events_show, |
| }, |
| { } /* terminate */ |
| }; |
| |
| static struct cftype memsw_files[] = { |
| { |
| .name = "memsw.usage_in_bytes", |
| .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| { |
| .name = "memsw.max_usage_in_bytes", |
| .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE), |
| .write = mem_cgroup_reset, |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| { |
| .name = "memsw.limit_in_bytes", |
| .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT), |
| .write = mem_cgroup_write, |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| { |
| .name = "memsw.failcnt", |
| .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT), |
| .write = mem_cgroup_reset, |
| .read_u64 = mem_cgroup_read_u64, |
| }, |
| { }, /* terminate */ |
| }; |
| |
| /* |
| * If mem_cgroup_swap_init() is implemented as a subsys_initcall() |
| * instead of a core_initcall(), this could mean cgroup_memory_noswap still |
| * remains set to false even when memcg is disabled via "cgroup_disable=memory" |
| * boot parameter. This may result in premature OOPS inside |
| * mem_cgroup_get_nr_swap_pages() function in corner cases. |
| */ |
| static int __init mem_cgroup_swap_init(void) |
| { |
| /* No memory control -> no swap control */ |
| if (mem_cgroup_disabled()) |
| cgroup_memory_noswap = true; |
| |
| if (cgroup_memory_noswap) |
| return 0; |
| |
| WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, swap_files)); |
| WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, memsw_files)); |
| |
| return 0; |
| } |
| core_initcall(mem_cgroup_swap_init); |
| |
| #endif /* CONFIG_MEMCG_SWAP */ |