v4.19.13 snapshot.
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
new file mode 100644
index 0000000..e79cb59
--- /dev/null
+++ b/mm/memcontrol.c
@@ -0,0 +1,6704 @@
+/* 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
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/page_counter.h>
+#include <linux/memcontrol.h>
+#include <linux/cgroup.h>
+#include <linux/mm.h>
+#include <linux/sched/mm.h>
+#include <linux/shmem_fs.h>
+#include <linux/hugetlb.h>
+#include <linux/pagemap.h>
+#include <linux/smp.h>
+#include <linux/page-flags.h>
+#include <linux/backing-dev.h>
+#include <linux/bit_spinlock.h>
+#include <linux/rcupdate.h>
+#include <linux/limits.h>
+#include <linux/export.h>
+#include <linux/mutex.h>
+#include <linux/rbtree.h>
+#include <linux/slab.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+#include <linux/spinlock.h>
+#include <linux/eventfd.h>
+#include <linux/poll.h>
+#include <linux/sort.h>
+#include <linux/fs.h>
+#include <linux/seq_file.h>
+#include <linux/vmpressure.h>
+#include <linux/mm_inline.h>
+#include <linux/swap_cgroup.h>
+#include <linux/cpu.h>
+#include <linux/oom.h>
+#include <linux/lockdep.h>
+#include <linux/file.h>
+#include <linux/tracehook.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;
+
+#define MEM_CGROUP_RECLAIM_RETRIES 5
+
+/* 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
+int do_swap_account __read_mostly;
+#else
+#define do_swap_account 0
+#endif
+
+/* Whether legacy memory+swap accounting is active */
+static bool do_memsw_account(void)
+{
+ return !cgroup_subsys_on_dfl(memory_cgrp_subsys) && do_swap_account;
+}
+
+static const char *const mem_cgroup_lru_names[] = {
+ "inactive_anon",
+ "active_anon",
+ "inactive_file",
+ "active_file",
+ "unevictable",
+};
+
+#define THRESHOLDS_EVENTS_TARGET 128
+#define SOFTLIMIT_EVENTS_TARGET 1024
+#define NUMAINFO_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
+
+enum charge_type {
+ MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
+ MEM_CGROUP_CHARGE_TYPE_ANON,
+ MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
+ MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
+ NR_CHARGE_TYPE,
+};
+
+/* for encoding cft->private value on file */
+enum res_type {
+ _MEM,
+ _MEMSWAP,
+ _OOM_TYPE,
+ _KMEM,
+ _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))
+
+/* 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
+/*
+ * This will be the memcg's index in each cache's ->memcg_params.memcg_caches.
+ * The main reason for not using cgroup id for this:
+ * this works better in sparse environments, where we have a lot of memcgs,
+ * but only a few kmem-limited. Or also, if we have, for instance, 200
+ * memcgs, and none but the 200th is kmem-limited, we'd have to have a
+ * 200 entry array for that.
+ *
+ * The current size of the caches array is stored in memcg_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_kmem_get_cache are
+ * conditional to this static branch, we'll have to allow modules that does
+ * kmem_cache_alloc and the such to see this symbol as well
+ */
+DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key);
+EXPORT_SYMBOL(memcg_kmem_enabled_key);
+
+struct workqueue_struct *memcg_kmem_cache_wq;
+
+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(sizeof(*new) + size, GFP_KERNEL);
+ 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(sizeof(*map) + size, GFP_KERNEL);
+ 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)
+ 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();
+ }
+}
+
+#else /* CONFIG_MEMCG_KMEM */
+static int memcg_alloc_shrinker_maps(struct mem_cgroup *memcg)
+{
+ return 0;
+}
+static void memcg_free_shrinker_maps(struct mem_cgroup *memcg) { }
+#endif /* CONFIG_MEMCG_KMEM */
+
+/**
+ * mem_cgroup_css_from_page - css of the memcg associated with a page
+ * @page: page of interest
+ *
+ * If memcg is bound to the default hierarchy, css of the memcg associated
+ * with @page is returned. The returned css remains associated with @page
+ * until it is released.
+ *
+ * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
+ * is returned.
+ */
+struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page)
+{
+ struct mem_cgroup *memcg;
+
+ memcg = page->mem_cgroup;
+
+ if (!memcg || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
+ memcg = root_mem_cgroup;
+
+ return &memcg->css;
+}
+
+/**
+ * page_cgroup_ino - return inode number of the memcg a page is charged to
+ * @page: the page
+ *
+ * Look up the closest online ancestor of the memory cgroup @page is charged to
+ * and return its inode number or 0 if @page is not charged to any cgroup. It
+ * is safe to call this function without holding a reference to @page.
+ *
+ * Note, this function is inherently racy, because there is nothing to prevent
+ * the cgroup inode from getting torn down and potentially reallocated a moment
+ * after page_cgroup_ino() returns, so it only should be used by callers that
+ * do not care (such as procfs interfaces).
+ */
+ino_t page_cgroup_ino(struct page *page)
+{
+ struct mem_cgroup *memcg;
+ unsigned long ino = 0;
+
+ rcu_read_lock();
+ memcg = READ_ONCE(page->mem_cgroup);
+ while (memcg && !(memcg->css.flags & CSS_ONLINE))
+ memcg = parent_mem_cgroup(memcg);
+ if (memcg)
+ ino = cgroup_ino(memcg->css.cgroup);
+ rcu_read_unlock();
+ return ino;
+}
+
+static struct mem_cgroup_per_node *
+mem_cgroup_page_nodeinfo(struct mem_cgroup *memcg, struct page *page)
+{
+ int nid = page_to_nid(page);
+
+ return memcg->nodeinfo[nid];
+}
+
+static struct mem_cgroup_tree_per_node *
+soft_limit_tree_node(int nid)
+{
+ return soft_limit_tree.rb_tree_per_node[nid];
+}
+
+static struct mem_cgroup_tree_per_node *
+soft_limit_tree_from_page(struct page *page)
+{
+ int nid = page_to_nid(page);
+
+ return soft_limit_tree.rb_tree_per_node[nid];
+}
+
+static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz,
+ struct mem_cgroup_tree_per_node *mctz,
+ unsigned long new_usage_in_excess)
+{
+ struct rb_node **p = &mctz->rb_root.rb_node;
+ struct rb_node *parent = NULL;
+ struct mem_cgroup_per_node *mz_node;
+ bool rightmost = true;
+
+ if (mz->on_tree)
+ return;
+
+ mz->usage_in_excess = new_usage_in_excess;
+ if (!mz->usage_in_excess)
+ return;
+ while (*p) {
+ parent = *p;
+ mz_node = rb_entry(parent, struct mem_cgroup_per_node,
+ tree_node);
+ if (mz->usage_in_excess < mz_node->usage_in_excess) {
+ p = &(*p)->rb_left;
+ rightmost = false;
+ }
+
+ /*
+ * We can't avoid mem cgroups that are over their soft
+ * limit by the same amount
+ */
+ else if (mz->usage_in_excess >= mz_node->usage_in_excess)
+ p = &(*p)->rb_right;
+ }
+
+ if (rightmost)
+ mctz->rb_rightmost = &mz->tree_node;
+
+ rb_link_node(&mz->tree_node, parent, p);
+ rb_insert_color(&mz->tree_node, &mctz->rb_root);
+ mz->on_tree = true;
+}
+
+static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
+ struct mem_cgroup_tree_per_node *mctz)
+{
+ if (!mz->on_tree)
+ return;
+
+ if (&mz->tree_node == mctz->rb_rightmost)
+ mctz->rb_rightmost = rb_prev(&mz->tree_node);
+
+ rb_erase(&mz->tree_node, &mctz->rb_root);
+ mz->on_tree = false;
+}
+
+static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
+ struct mem_cgroup_tree_per_node *mctz)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&mctz->lock, flags);
+ __mem_cgroup_remove_exceeded(mz, mctz);
+ spin_unlock_irqrestore(&mctz->lock, flags);
+}
+
+static unsigned long soft_limit_excess(struct mem_cgroup *memcg)
+{
+ unsigned long nr_pages = page_counter_read(&memcg->memory);
+ unsigned long soft_limit = READ_ONCE(memcg->soft_limit);
+ unsigned long excess = 0;
+
+ if (nr_pages > soft_limit)
+ excess = nr_pages - soft_limit;
+
+ return excess;
+}
+
+static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
+{
+ unsigned long excess;
+ struct mem_cgroup_per_node *mz;
+ struct mem_cgroup_tree_per_node *mctz;
+
+ mctz = soft_limit_tree_from_page(page);
+ if (!mctz)
+ return;
+ /*
+ * Necessary to update all ancestors when hierarchy is used.
+ * because their event counter is not touched.
+ */
+ for (; memcg; memcg = parent_mem_cgroup(memcg)) {
+ mz = mem_cgroup_page_nodeinfo(memcg, page);
+ excess = soft_limit_excess(memcg);
+ /*
+ * We have to update the tree if mz is on RB-tree or
+ * mem is over its softlimit.
+ */
+ if (excess || mz->on_tree) {
+ unsigned long flags;
+
+ spin_lock_irqsave(&mctz->lock, flags);
+ /* if on-tree, remove it */
+ if (mz->on_tree)
+ __mem_cgroup_remove_exceeded(mz, mctz);
+ /*
+ * Insert again. mz->usage_in_excess will be updated.
+ * If excess is 0, no tree ops.
+ */
+ __mem_cgroup_insert_exceeded(mz, mctz, excess);
+ spin_unlock_irqrestore(&mctz->lock, flags);
+ }
+ }
+}
+
+static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
+{
+ struct mem_cgroup_tree_per_node *mctz;
+ struct mem_cgroup_per_node *mz;
+ int nid;
+
+ for_each_node(nid) {
+ mz = mem_cgroup_nodeinfo(memcg, nid);
+ mctz = soft_limit_tree_node(nid);
+ if (mctz)
+ mem_cgroup_remove_exceeded(mz, mctz);
+ }
+}
+
+static struct mem_cgroup_per_node *
+__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
+{
+ struct mem_cgroup_per_node *mz;
+
+retry:
+ mz = NULL;
+ if (!mctz->rb_rightmost)
+ goto done; /* Nothing to reclaim from */
+
+ mz = rb_entry(mctz->rb_rightmost,
+ struct mem_cgroup_per_node, tree_node);
+ /*
+ * Remove the node now but someone else can add it back,
+ * we will to add it back at the end of reclaim to its correct
+ * position in the tree.
+ */
+ __mem_cgroup_remove_exceeded(mz, mctz);
+ if (!soft_limit_excess(mz->memcg) ||
+ !css_tryget_online(&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;
+}
+
+static unsigned long memcg_sum_events(struct mem_cgroup *memcg,
+ int event)
+{
+ return atomic_long_read(&memcg->events[event]);
+}
+
+static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
+ struct page *page,
+ bool compound, int nr_pages)
+{
+ /*
+ * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
+ * counted as CACHE even if it's on ANON LRU.
+ */
+ if (PageAnon(page))
+ __mod_memcg_state(memcg, MEMCG_RSS, nr_pages);
+ else {
+ __mod_memcg_state(memcg, MEMCG_CACHE, nr_pages);
+ if (PageSwapBacked(page))
+ __mod_memcg_state(memcg, NR_SHMEM, nr_pages);
+ }
+
+ if (compound) {
+ VM_BUG_ON_PAGE(!PageTransHuge(page), page);
+ __mod_memcg_state(memcg, MEMCG_RSS_HUGE, 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->stat_cpu->nr_page_events, nr_pages);
+}
+
+unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
+ int nid, unsigned int lru_mask)
+{
+ struct lruvec *lruvec = mem_cgroup_lruvec(NODE_DATA(nid), memcg);
+ 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;
+ nr += mem_cgroup_get_lru_size(lruvec, lru);
+ }
+ return nr;
+}
+
+static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
+ unsigned int lru_mask)
+{
+ unsigned long nr = 0;
+ int nid;
+
+ for_each_node_state(nid, N_MEMORY)
+ nr += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask);
+ return nr;
+}
+
+static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
+ enum mem_cgroup_events_target target)
+{
+ unsigned long val, next;
+
+ val = __this_cpu_read(memcg->stat_cpu->nr_page_events);
+ next = __this_cpu_read(memcg->stat_cpu->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;
+ case MEM_CGROUP_TARGET_NUMAINFO:
+ next = val + NUMAINFO_EVENTS_TARGET;
+ break;
+ default:
+ break;
+ }
+ __this_cpu_write(memcg->stat_cpu->targets[target], next);
+ return true;
+ }
+ return false;
+}
+
+/*
+ * Check events in order.
+ *
+ */
+static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
+{
+ /* threshold event is triggered in finer grain than soft limit */
+ if (unlikely(mem_cgroup_event_ratelimit(memcg,
+ MEM_CGROUP_TARGET_THRESH))) {
+ bool do_softlimit;
+ bool do_numainfo __maybe_unused;
+
+ do_softlimit = mem_cgroup_event_ratelimit(memcg,
+ MEM_CGROUP_TARGET_SOFTLIMIT);
+#if MAX_NUMNODES > 1
+ do_numainfo = mem_cgroup_event_ratelimit(memcg,
+ MEM_CGROUP_TARGET_NUMAINFO);
+#endif
+ mem_cgroup_threshold(memcg);
+ if (unlikely(do_softlimit))
+ mem_cgroup_update_tree(memcg, page);
+#if MAX_NUMNODES > 1
+ if (unlikely(do_numainfo))
+ atomic_inc(&memcg->numainfo_events);
+#endif
+ }
+}
+
+struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
+{
+ /*
+ * mm_update_next_owner() may clear mm->owner to NULL
+ * if it races with swapoff, page migration, etc.
+ * So this can be called with p == NULL.
+ */
+ if (unlikely(!p))
+ return NULL;
+
+ return mem_cgroup_from_css(task_css(p, memory_cgrp_id));
+}
+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_online(&memcg->css));
+ rcu_read_unlock();
+ return memcg;
+}
+EXPORT_SYMBOL(get_mem_cgroup_from_mm);
+
+/**
+ * get_mem_cgroup_from_page: Obtain a reference on given page's memcg.
+ * @page: page from which memcg should be extracted.
+ *
+ * Obtain a reference on page->memcg and returns it if successful. Otherwise
+ * root_mem_cgroup is returned.
+ */
+struct mem_cgroup *get_mem_cgroup_from_page(struct page *page)
+{
+ struct mem_cgroup *memcg = page->mem_cgroup;
+
+ if (mem_cgroup_disabled())
+ return NULL;
+
+ rcu_read_lock();
+ if (!memcg || !css_tryget_online(&memcg->css))
+ memcg = root_mem_cgroup;
+ rcu_read_unlock();
+ return memcg;
+}
+EXPORT_SYMBOL(get_mem_cgroup_from_page);
+
+/**
+ * If current->active_memcg is non-NULL, do not fallback to current->mm->memcg.
+ */
+static __always_inline struct mem_cgroup *get_mem_cgroup_from_current(void)
+{
+ if (unlikely(current->active_memcg)) {
+ struct mem_cgroup *memcg = root_mem_cgroup;
+
+ rcu_read_lock();
+ if (css_tryget_online(¤t->active_memcg->css))
+ memcg = current->active_memcg;
+ rcu_read_unlock();
+ return 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 and a priority level in @reclaim to
+ * divide up the memcgs in the hierarchy among all concurrent
+ * reclaimers operating on the same node and priority.
+ */
+struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
+ struct mem_cgroup *prev,
+ struct mem_cgroup_reclaim_cookie *reclaim)
+{
+ struct mem_cgroup_reclaim_iter *uninitialized_var(iter);
+ struct cgroup_subsys_state *css = NULL;
+ struct mem_cgroup *memcg = NULL;
+ struct mem_cgroup *pos = NULL;
+
+ if (mem_cgroup_disabled())
+ return NULL;
+
+ if (!root)
+ root = root_mem_cgroup;
+
+ if (prev && !reclaim)
+ pos = prev;
+
+ if (!root->use_hierarchy && root != root_mem_cgroup) {
+ if (prev)
+ goto out;
+ return root;
+ }
+
+ rcu_read_lock();
+
+ if (reclaim) {
+ struct mem_cgroup_per_node *mz;
+
+ mz = mem_cgroup_nodeinfo(root, reclaim->pgdat->node_id);
+ iter = &mz->iter[reclaim->priority];
+
+ if (prev && reclaim->generation != iter->generation)
+ goto out_unlock;
+
+ while (1) {
+ pos = READ_ONCE(iter->position);
+ if (!pos || css_tryget(&pos->css))
+ break;
+ /*
+ * css reference reached zero, so iter->position will
+ * be cleared by ->css_released. However, we should not
+ * rely on this happening soon, because ->css_released
+ * is called from a work queue, and by busy-waiting we
+ * might block it. So we clear iter->position right
+ * away.
+ */
+ (void)cmpxchg(&iter->position, pos, NULL);
+ }
+ }
+
+ if (pos)
+ css = &pos->css;
+
+ for (;;) {
+ css = css_next_descendant_pre(css, &root->css);
+ if (!css) {
+ /*
+ * Reclaimers share the hierarchy walk, and a
+ * new one might jump in right at the end of
+ * the hierarchy - make sure they see at least
+ * one group and restart from the beginning.
+ */
+ if (!prev)
+ continue;
+ break;
+ }
+
+ /*
+ * Verify the css and acquire a reference. The root
+ * is provided by the caller, so we know it's alive
+ * and kicking, and don't take an extra reference.
+ */
+ memcg = mem_cgroup_from_css(css);
+
+ if (css == &root->css)
+ break;
+
+ if (css_tryget(css))
+ break;
+
+ memcg = NULL;
+ }
+
+ if (reclaim) {
+ /*
+ * The position could have already been updated by a competing
+ * thread, so check that the value hasn't changed since we read
+ * it to avoid reclaiming from the same cgroup twice.
+ */
+ (void)cmpxchg(&iter->position, pos, memcg);
+
+ if (pos)
+ css_put(&pos->css);
+
+ if (!memcg)
+ iter->generation++;
+ else if (!prev)
+ reclaim->generation = iter->generation;
+ }
+
+out_unlock:
+ rcu_read_unlock();
+out:
+ if (prev && prev != root)
+ css_put(&prev->css);
+
+ return memcg;
+}
+
+/**
+ * mem_cgroup_iter_break - abort a hierarchy walk prematurely
+ * @root: hierarchy root
+ * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
+ */
+void mem_cgroup_iter_break(struct mem_cgroup *root,
+ struct mem_cgroup *prev)
+{
+ if (!root)
+ root = root_mem_cgroup;
+ if (prev && prev != root)
+ css_put(&prev->css);
+}
+
+static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
+{
+ struct mem_cgroup *memcg = dead_memcg;
+ struct mem_cgroup_reclaim_iter *iter;
+ struct mem_cgroup_per_node *mz;
+ int nid;
+ int i;
+
+ for (; memcg; memcg = parent_mem_cgroup(memcg)) {
+ for_each_node(nid) {
+ mz = mem_cgroup_nodeinfo(memcg, nid);
+ for (i = 0; i <= DEF_PRIORITY; i++) {
+ iter = &mz->iter[i];
+ cmpxchg(&iter->position,
+ dead_memcg, NULL);
+ }
+ }
+ }
+}
+
+/**
+ * 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, 0, &it);
+ while (!ret && (task = css_task_iter_next(&it)))
+ ret = fn(task, arg);
+ css_task_iter_end(&it);
+ if (ret) {
+ mem_cgroup_iter_break(memcg, iter);
+ break;
+ }
+ }
+ return ret;
+}
+
+/**
+ * mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page
+ * @page: the page
+ * @pgdat: pgdat of the page
+ *
+ * This function is only safe when following the LRU page isolation
+ * and putback protocol: the LRU lock must be held, and the page must
+ * either be PageLRU() or the caller must have isolated/allocated it.
+ */
+struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgdat)
+{
+ struct mem_cgroup_per_node *mz;
+ struct mem_cgroup *memcg;
+ struct lruvec *lruvec;
+
+ if (mem_cgroup_disabled()) {
+ lruvec = &pgdat->lruvec;
+ goto out;
+ }
+
+ memcg = page->mem_cgroup;
+ /*
+ * Swapcache readahead pages are added to the LRU - and
+ * possibly migrated - before they are charged.
+ */
+ if (!memcg)
+ memcg = root_mem_cgroup;
+
+ mz = mem_cgroup_page_nodeinfo(memcg, page);
+ lruvec = &mz->lruvec;
+out:
+ /*
+ * Since a node can be onlined after the mem_cgroup was created,
+ * we have to be prepared to initialize lruvec->zone here;
+ * and if offlined then reonlined, we need to reinitialize it.
+ */
+ if (unlikely(lruvec->pgdat != pgdat))
+ lruvec->pgdat = pgdat;
+ return lruvec;
+}
+
+/**
+ * mem_cgroup_update_lru_size - account for adding or removing an lru page
+ * @lruvec: mem_cgroup per zone lru vector
+ * @lru: index of lru list the page is sitting on
+ * @zid: zone id of the accounted pages
+ * @nr_pages: positive when adding or negative when removing
+ *
+ * This function must be called under lru_lock, just before a page is added
+ * to or just after a page is removed from an lru list (that ordering being
+ * so as to allow it to check that lru_size 0 is consistent with list_empty).
+ */
+void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
+ int zid, int nr_pages)
+{
+ struct mem_cgroup_per_node *mz;
+ unsigned long *lru_size;
+ long size;
+
+ if (mem_cgroup_disabled())
+ return;
+
+ mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
+ lru_size = &mz->lru_zone_size[zid][lru];
+
+ if (nr_pages < 0)
+ *lru_size += nr_pages;
+
+ size = *lru_size;
+ if (WARN_ONCE(size < 0,
+ "%s(%p, %d, %d): lru_size %ld\n",
+ __func__, lruvec, lru, nr_pages, size)) {
+ VM_BUG_ON(1);
+ *lru_size = 0;
+ }
+
+ if (nr_pages > 0)
+ *lru_size += nr_pages;
+}
+
+bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg)
+{
+ struct mem_cgroup *task_memcg;
+ struct task_struct *p;
+ bool ret;
+
+ p = find_lock_task_mm(task);
+ if (p) {
+ task_memcg = get_mem_cgroup_from_mm(p->mm);
+ task_unlock(p);
+ } else {
+ /*
+ * All threads may have already detached their mm's, but the oom
+ * killer still needs to detect if they have already been oom
+ * killed to prevent needlessly killing additional tasks.
+ */
+ rcu_read_lock();
+ task_memcg = mem_cgroup_from_task(task);
+ css_get(&task_memcg->css);
+ rcu_read_unlock();
+ }
+ ret = mem_cgroup_is_descendant(task_memcg, memcg);
+ css_put(&task_memcg->css);
+ return ret;
+}
+
+/**
+ * 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;
+}
+
+static const unsigned int memcg1_stats[] = {
+ MEMCG_CACHE,
+ MEMCG_RSS,
+ MEMCG_RSS_HUGE,
+ NR_SHMEM,
+ NR_FILE_MAPPED,
+ NR_FILE_DIRTY,
+ NR_WRITEBACK,
+ MEMCG_SWAP,
+};
+
+static const char *const memcg1_stat_names[] = {
+ "cache",
+ "rss",
+ "rss_huge",
+ "shmem",
+ "mapped_file",
+ "dirty",
+ "writeback",
+ "swap",
+};
+
+#define K(x) ((x) << (PAGE_SHIFT-10))
+/**
+ * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
+ * @memcg: The memory cgroup that went over limit
+ * @p: Task that is going to be killed
+ *
+ * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
+ * enabled
+ */
+void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
+{
+ struct mem_cgroup *iter;
+ unsigned int i;
+
+ rcu_read_lock();
+
+ if (p) {
+ pr_info("Task in ");
+ pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
+ pr_cont(" killed as a result of limit of ");
+ } else {
+ pr_info("Memory limit reached of cgroup ");
+ }
+
+ pr_cont_cgroup_path(memcg->css.cgroup);
+ pr_cont("\n");
+
+ rcu_read_unlock();
+
+ pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
+ K((u64)page_counter_read(&memcg->memory)),
+ K((u64)memcg->memory.max), memcg->memory.failcnt);
+ pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
+ K((u64)page_counter_read(&memcg->memsw)),
+ K((u64)memcg->memsw.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);
+
+ for_each_mem_cgroup_tree(iter, memcg) {
+ pr_info("Memory cgroup stats for ");
+ pr_cont_cgroup_path(iter->css.cgroup);
+ pr_cont(":");
+
+ for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
+ if (memcg1_stats[i] == MEMCG_SWAP && !do_swap_account)
+ continue;
+ pr_cont(" %s:%luKB", memcg1_stat_names[i],
+ K(memcg_page_state(iter, memcg1_stats[i])));
+ }
+
+ for (i = 0; i < NR_LRU_LISTS; i++)
+ pr_cont(" %s:%luKB", mem_cgroup_lru_names[i],
+ K(mem_cgroup_nr_lru_pages(iter, BIT(i))));
+
+ pr_cont("\n");
+ }
+}
+
+/*
+ * Return the memory (and swap, if configured) limit for a memcg.
+ */
+unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg)
+{
+ unsigned long max;
+
+ max = memcg->memory.max;
+ if (mem_cgroup_swappiness(memcg)) {
+ unsigned long memsw_max;
+ unsigned long swap_max;
+
+ memsw_max = memcg->memsw.max;
+ swap_max = memcg->swap.max;
+ swap_max = min(swap_max, (unsigned long)total_swap_pages);
+ max = min(max + swap_max, memsw_max);
+ }
+ return max;
+}
+
+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;
+
+ mutex_lock(&oom_lock);
+ ret = out_of_memory(&oc);
+ mutex_unlock(&oom_lock);
+ return ret;
+}
+
+#if MAX_NUMNODES > 1
+
+/**
+ * test_mem_cgroup_node_reclaimable
+ * @memcg: the target memcg
+ * @nid: the node ID to be checked.
+ * @noswap : specify true here if the user wants flle only information.
+ *
+ * This function returns whether the specified memcg contains any
+ * reclaimable pages on a node. Returns true if there are any reclaimable
+ * pages in the node.
+ */
+static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
+ int nid, bool noswap)
+{
+ if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
+ return true;
+ if (noswap || !total_swap_pages)
+ return false;
+ if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
+ return true;
+ return false;
+
+}
+
+/*
+ * Always updating the nodemask is not very good - even if we have an empty
+ * list or the wrong list here, we can start from some node and traverse all
+ * nodes based on the zonelist. So update the list loosely once per 10 secs.
+ *
+ */
+static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
+{
+ int nid;
+ /*
+ * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
+ * pagein/pageout changes since the last update.
+ */
+ if (!atomic_read(&memcg->numainfo_events))
+ return;
+ if (atomic_inc_return(&memcg->numainfo_updating) > 1)
+ return;
+
+ /* make a nodemask where this memcg uses memory from */
+ memcg->scan_nodes = node_states[N_MEMORY];
+
+ for_each_node_mask(nid, node_states[N_MEMORY]) {
+
+ if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
+ node_clear(nid, memcg->scan_nodes);
+ }
+
+ atomic_set(&memcg->numainfo_events, 0);
+ atomic_set(&memcg->numainfo_updating, 0);
+}
+
+/*
+ * Selecting a node where we start reclaim from. Because what we need is just
+ * reducing usage counter, start from anywhere is O,K. Considering
+ * memory reclaim from current node, there are pros. and cons.
+ *
+ * Freeing memory from current node means freeing memory from a node which
+ * we'll use or we've used. So, it may make LRU bad. And if several threads
+ * hit limits, it will see a contention on a node. But freeing from remote
+ * node means more costs for memory reclaim because of memory latency.
+ *
+ * Now, we use round-robin. Better algorithm is welcomed.
+ */
+int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
+{
+ int node;
+
+ mem_cgroup_may_update_nodemask(memcg);
+ node = memcg->last_scanned_node;
+
+ node = next_node_in(node, memcg->scan_nodes);
+ /*
+ * mem_cgroup_may_update_nodemask might have seen no reclaimmable pages
+ * last time it really checked all the LRUs due to rate limiting.
+ * Fallback to the current node in that case for simplicity.
+ */
+ if (unlikely(node == MAX_NUMNODES))
+ node = numa_node_id();
+
+ memcg->last_scanned_node = node;
+ return node;
+}
+#else
+int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
+{
+ return 0;
+}
+#endif
+
+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,
+ .priority = 0,
+ };
+
+ excess = soft_limit_excess(root_memcg);
+
+ while (1) {
+ victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
+ if (!victim) {
+ loop++;
+ if (loop >= 2) {
+ /*
+ * If we have not been able to reclaim
+ * anything, it might because there are
+ * no reclaimable pages under this hierarchy
+ */
+ if (!total)
+ break;
+ /*
+ * We want to do more targeted reclaim.
+ * excess >> 2 is not to excessive so as to
+ * reclaim too much, nor too less that we keep
+ * coming back to reclaim from this cgroup
+ */
+ if (total >= (excess >> 2) ||
+ (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
+ break;
+ }
+ continue;
+ }
+ 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, 1, _RET_IP_);
+ for_each_mem_cgroup_tree(iter, memcg)
+ iter->oom_lock = false;
+ spin_unlock(&memcg_oom_lock);
+}
+
+static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
+{
+ struct mem_cgroup *iter;
+
+ 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;
+
+ /*
+ * When a new child is created while the hierarchy is under oom,
+ * mem_cgroup_oom_lock() may not be called. Watch for underflow.
+ */
+ 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)
+{
+ if (order > PAGE_ALLOC_COSTLY_ORDER)
+ return OOM_SKIPPED;
+
+ /*
+ * 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;
+ }
+
+ if (mem_cgroup_out_of_memory(memcg, mask, order))
+ return OOM_SUCCESS;
+
+ return OOM_FAILED;
+}
+
+/**
+ * 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;
+
+ /*
+ * Traverse the memory cgroup hierarchy from the victim task's
+ * cgroup up to the OOMing cgroup (or root) to find the
+ * highest-level memory cgroup with oom.group set.
+ */
+ for (; memcg; memcg = parent_mem_cgroup(memcg)) {
+ if (memcg->oom_group)
+ oom_group = memcg;
+
+ if (memcg == oom_domain)
+ break;
+ }
+
+ if (oom_group)
+ css_get(&oom_group->css);
+out:
+ rcu_read_unlock();
+
+ return oom_group;
+}
+
+void mem_cgroup_print_oom_group(struct mem_cgroup *memcg)
+{
+ pr_info("Tasks in ");
+ pr_cont_cgroup_path(memcg->css.cgroup);
+ pr_cont(" are going to be killed due to memory.oom.group set\n");
+}
+
+/**
+ * lock_page_memcg - lock a page->mem_cgroup binding
+ * @page: the page
+ *
+ * This function protects unlocked LRU pages from being moved to
+ * another cgroup.
+ *
+ * It ensures lifetime of the returned memcg. Caller is responsible
+ * for the lifetime of the page; __unlock_page_memcg() is available
+ * when @page might get freed inside the locked section.
+ */
+struct mem_cgroup *lock_page_memcg(struct page *page)
+{
+ struct 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->mem_cgroup;
+ if (unlikely(!memcg))
+ return NULL;
+
+ if (atomic_read(&memcg->moving_account) <= 0)
+ return memcg;
+
+ spin_lock_irqsave(&memcg->move_lock, flags);
+ if (memcg != page->mem_cgroup) {
+ spin_unlock_irqrestore(&memcg->move_lock, flags);
+ goto again;
+ }
+
+ /*
+ * When charge migration first begins, we can have locked and
+ * unlocked page stat updates happening concurrently. Track
+ * the task who has the lock for unlock_page_memcg().
+ */
+ memcg->move_lock_task = current;
+ memcg->move_lock_flags = flags;
+
+ return memcg;
+}
+EXPORT_SYMBOL(lock_page_memcg);
+
+/**
+ * __unlock_page_memcg - unlock and unpin a memcg
+ * @memcg: the memcg
+ *
+ * Unlock and unpin a memcg returned by lock_page_memcg().
+ */
+void __unlock_page_memcg(struct mem_cgroup *memcg)
+{
+ if (memcg && memcg->move_lock_task == current) {
+ unsigned long flags = memcg->move_lock_flags;
+
+ memcg->move_lock_task = NULL;
+ memcg->move_lock_flags = 0;
+
+ spin_unlock_irqrestore(&memcg->move_lock, flags);
+ }
+
+ rcu_read_unlock();
+}
+
+/**
+ * unlock_page_memcg - unlock a page->mem_cgroup binding
+ * @page: the page
+ */
+void unlock_page_memcg(struct page *page)
+{
+ __unlock_page_memcg(page->mem_cgroup);
+}
+EXPORT_SYMBOL(unlock_page_memcg);
+
+struct memcg_stock_pcp {
+ struct mem_cgroup *cached; /* this never be root cgroup */
+ unsigned int nr_pages;
+ struct work_struct work;
+ unsigned long flags;
+#define FLUSHING_CACHED_CHARGE 0
+};
+static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
+static DEFINE_MUTEX(percpu_charge_mutex);
+
+/**
+ * consume_stock: Try to consume stocked charge on this cpu.
+ * @memcg: memcg to consume from.
+ * @nr_pages: how many pages to charge.
+ *
+ * The charges will only happen if @memcg matches the current cpu's memcg
+ * stock, and at least @nr_pages are available in that stock. Failure to
+ * service an allocation will refill the stock.
+ *
+ * returns true if successful, false otherwise.
+ */
+static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
+{
+ struct memcg_stock_pcp *stock;
+ 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 (stock->nr_pages) {
+ page_counter_uncharge(&old->memory, stock->nr_pages);
+ if (do_memsw_account())
+ page_counter_uncharge(&old->memsw, stock->nr_pages);
+ css_put_many(&old->css, stock->nr_pages);
+ stock->nr_pages = 0;
+ }
+ 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_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);
+ 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;
+
+ memcg = stock->cached;
+ if (!memcg || !stock->nr_pages || !css_tryget(&memcg->css))
+ continue;
+ if (!mem_cgroup_is_descendant(memcg, root_memcg)) {
+ css_put(&memcg->css);
+ continue;
+ }
+ if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
+ if (cpu == curcpu)
+ drain_local_stock(&stock->work);
+ else
+ schedule_work_on(cpu, &stock->work);
+ }
+ css_put(&memcg->css);
+ }
+ 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;
+
+ 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->stat_cpu->count[i], 0);
+ if (x)
+ atomic_long_add(x, &memcg->stat[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)
+ atomic_long_add(x, &pn->lruvec_stat[i]);
+ }
+ }
+
+ for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
+ long x;
+
+ x = this_cpu_xchg(memcg->stat_cpu->events[i], 0);
+ if (x)
+ atomic_long_add(x, &memcg->events[i]);
+ }
+ }
+
+ return 0;
+}
+
+static void reclaim_high(struct mem_cgroup *memcg,
+ unsigned int nr_pages,
+ gfp_t gfp_mask)
+{
+ do {
+ if (page_counter_read(&memcg->memory) <= memcg->high)
+ continue;
+ memcg_memory_event(memcg, MEMCG_HIGH);
+ try_to_free_mem_cgroup_pages(memcg, nr_pages, gfp_mask, true);
+ } while ((memcg = parent_mem_cgroup(memcg)));
+}
+
+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);
+}
+
+/*
+ * 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 int nr_pages = current->memcg_nr_pages_over_high;
+ struct mem_cgroup *memcg;
+
+ if (likely(!nr_pages))
+ return;
+
+ memcg = get_mem_cgroup_from_mm(current->mm);
+ reclaim_high(memcg, nr_pages, GFP_KERNEL);
+ css_put(&memcg->css);
+ current->memcg_nr_pages_over_high = 0;
+}
+
+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 = MEM_CGROUP_RECLAIM_RETRIES;
+ struct mem_cgroup *mem_over_limit;
+ struct page_counter *counter;
+ unsigned long nr_reclaimed;
+ bool may_swap = true;
+ bool drained = false;
+ bool oomed = false;
+ enum oom_status oom_status;
+
+ 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;
+ }
+
+ /*
+ * 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(tsk_is_oom_victim(current) ||
+ fatal_signal_pending(current) ||
+ current->flags & PF_EXITING))
+ 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);
+
+ nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages,
+ gfp_mask, may_swap);
+
+ if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
+ goto retry;
+
+ if (!drained) {
+ drain_all_stock(mem_over_limit);
+ drained = true;
+ goto retry;
+ }
+
+ if (gfp_mask & __GFP_NORETRY)
+ goto nomem;
+ /*
+ * Even though the limit is exceeded at this point, reclaim
+ * may have been able to free some pages. Retry the charge
+ * before killing the task.
+ *
+ * Only for regular pages, though: huge pages are rather
+ * unlikely to succeed so close to the limit, and we fall back
+ * to regular pages anyway in case of failure.
+ */
+ if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER))
+ goto retry;
+ /*
+ * At task move, charge accounts can be doubly counted. So, it's
+ * better to wait until the end of task_move if something is going on.
+ */
+ if (mem_cgroup_wait_acct_move(mem_over_limit))
+ goto retry;
+
+ if (nr_retries--)
+ goto retry;
+
+ if (gfp_mask & __GFP_RETRY_MAYFAIL && oomed)
+ goto nomem;
+
+ if (gfp_mask & __GFP_NOFAIL)
+ goto force;
+
+ if (fatal_signal_pending(current))
+ goto force;
+
+ memcg_memory_event(mem_over_limit, MEMCG_OOM);
+
+ /*
+ * 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 = MEM_CGROUP_RECLAIM_RETRIES;
+ oomed = true;
+ 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);
+ css_get_many(&memcg->css, nr_pages);
+
+ return 0;
+
+done_restock:
+ css_get_many(&memcg->css, batch);
+ 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 {
+ if (page_counter_read(&memcg->memory) > memcg->high) {
+ /* Don't bother a random interrupted task */
+ if (in_interrupt()) {
+ schedule_work(&memcg->high_work);
+ break;
+ }
+ current->memcg_nr_pages_over_high += batch;
+ set_notify_resume(current);
+ break;
+ }
+ } while ((memcg = parent_mem_cgroup(memcg)));
+
+ return 0;
+}
+
+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);
+
+ css_put_many(&memcg->css, nr_pages);
+}
+
+static void lock_page_lru(struct page *page, int *isolated)
+{
+ struct zone *zone = page_zone(page);
+
+ spin_lock_irq(zone_lru_lock(zone));
+ if (PageLRU(page)) {
+ struct lruvec *lruvec;
+
+ lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat);
+ ClearPageLRU(page);
+ del_page_from_lru_list(page, lruvec, page_lru(page));
+ *isolated = 1;
+ } else
+ *isolated = 0;
+}
+
+static void unlock_page_lru(struct page *page, int isolated)
+{
+ struct zone *zone = page_zone(page);
+
+ if (isolated) {
+ struct lruvec *lruvec;
+
+ lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat);
+ VM_BUG_ON_PAGE(PageLRU(page), page);
+ SetPageLRU(page);
+ add_page_to_lru_list(page, lruvec, page_lru(page));
+ }
+ spin_unlock_irq(zone_lru_lock(zone));
+}
+
+static void commit_charge(struct page *page, struct mem_cgroup *memcg,
+ bool lrucare)
+{
+ int isolated;
+
+ VM_BUG_ON_PAGE(page->mem_cgroup, page);
+
+ /*
+ * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
+ * may already be on some other mem_cgroup's LRU. Take care of it.
+ */
+ if (lrucare)
+ lock_page_lru(page, &isolated);
+
+ /*
+ * Nobody should be changing or seriously looking at
+ * page->mem_cgroup at this point:
+ *
+ * - the page is uncharged
+ *
+ * - the page is off-LRU
+ *
+ * - an anonymous fault has exclusive page access, except for
+ * a locked page table
+ *
+ * - a page cache insertion, a swapin fault, or a migration
+ * have the page locked
+ */
+ page->mem_cgroup = memcg;
+
+ if (lrucare)
+ unlock_page_lru(page, isolated);
+}
+
+#ifdef CONFIG_MEMCG_KMEM
+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_caches(size);
+ if (!err)
+ 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);
+}
+
+struct memcg_kmem_cache_create_work {
+ struct mem_cgroup *memcg;
+ struct kmem_cache *cachep;
+ struct work_struct work;
+};
+
+static void memcg_kmem_cache_create_func(struct work_struct *w)
+{
+ struct memcg_kmem_cache_create_work *cw =
+ container_of(w, struct memcg_kmem_cache_create_work, work);
+ struct mem_cgroup *memcg = cw->memcg;
+ struct kmem_cache *cachep = cw->cachep;
+
+ memcg_create_kmem_cache(memcg, cachep);
+
+ css_put(&memcg->css);
+ kfree(cw);
+}
+
+/*
+ * Enqueue the creation of a per-memcg kmem_cache.
+ */
+static void __memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
+ struct kmem_cache *cachep)
+{
+ struct memcg_kmem_cache_create_work *cw;
+
+ cw = kmalloc(sizeof(*cw), GFP_NOWAIT | __GFP_NOWARN);
+ if (!cw)
+ return;
+
+ css_get(&memcg->css);
+
+ cw->memcg = memcg;
+ cw->cachep = cachep;
+ INIT_WORK(&cw->work, memcg_kmem_cache_create_func);
+
+ queue_work(memcg_kmem_cache_wq, &cw->work);
+}
+
+static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
+ struct kmem_cache *cachep)
+{
+ /*
+ * We need to stop accounting when we kmalloc, because if the
+ * corresponding kmalloc cache is not yet created, the first allocation
+ * in __memcg_schedule_kmem_cache_create will recurse.
+ *
+ * However, it is better to enclose the whole function. Depending on
+ * the debugging options enabled, INIT_WORK(), for instance, can
+ * trigger an allocation. This too, will make us recurse. Because at
+ * this point we can't allow ourselves back into memcg_kmem_get_cache,
+ * the safest choice is to do it like this, wrapping the whole function.
+ */
+ current->memcg_kmem_skip_account = 1;
+ __memcg_schedule_kmem_cache_create(memcg, cachep);
+ current->memcg_kmem_skip_account = 0;
+}
+
+static inline bool memcg_kmem_bypass(void)
+{
+ if (in_interrupt() || !current->mm || (current->flags & PF_KTHREAD))
+ return true;
+ return false;
+}
+
+/**
+ * memcg_kmem_get_cache: select the correct per-memcg cache for allocation
+ * @cachep: the original global kmem cache
+ *
+ * Return the kmem_cache we're supposed to use for a slab allocation.
+ * We try to use the current memcg's version of the cache.
+ *
+ * If the cache does not exist yet, if we are the first user of it, we
+ * create it asynchronously in a workqueue and let the current allocation
+ * go through with the original cache.
+ *
+ * This function takes a reference to the cache it returns to assure it
+ * won't get destroyed while we are working with it. Once the caller is
+ * done with it, memcg_kmem_put_cache() must be called to release the
+ * reference.
+ */
+struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep)
+{
+ struct mem_cgroup *memcg;
+ struct kmem_cache *memcg_cachep;
+ int kmemcg_id;
+
+ VM_BUG_ON(!is_root_cache(cachep));
+
+ if (memcg_kmem_bypass())
+ return cachep;
+
+ if (current->memcg_kmem_skip_account)
+ return cachep;
+
+ memcg = get_mem_cgroup_from_current();
+ kmemcg_id = READ_ONCE(memcg->kmemcg_id);
+ if (kmemcg_id < 0)
+ goto out;
+
+ memcg_cachep = cache_from_memcg_idx(cachep, kmemcg_id);
+ if (likely(memcg_cachep))
+ return memcg_cachep;
+
+ /*
+ * If we are in a safe context (can wait, and not in interrupt
+ * context), we could be be predictable and return right away.
+ * This would guarantee that the allocation being performed
+ * already belongs in the new cache.
+ *
+ * However, there are some clashes that can arrive from locking.
+ * For instance, because we acquire the slab_mutex while doing
+ * memcg_create_kmem_cache, this means no further allocation
+ * could happen with the slab_mutex held. So it's better to
+ * defer everything.
+ */
+ memcg_schedule_kmem_cache_create(memcg, cachep);
+out:
+ css_put(&memcg->css);
+ return cachep;
+}
+
+/**
+ * memcg_kmem_put_cache: drop reference taken by memcg_kmem_get_cache
+ * @cachep: the cache returned by memcg_kmem_get_cache
+ */
+void memcg_kmem_put_cache(struct kmem_cache *cachep)
+{
+ if (!is_root_cache(cachep))
+ css_put(&cachep->memcg_params.memcg->css);
+}
+
+/**
+ * memcg_kmem_charge_memcg: charge a kmem page
+ * @page: page to charge
+ * @gfp: reclaim mode
+ * @order: allocation order
+ * @memcg: memory cgroup to charge
+ *
+ * Returns 0 on success, an error code on failure.
+ */
+int memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
+ struct mem_cgroup *memcg)
+{
+ unsigned int nr_pages = 1 << order;
+ 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)) {
+ cancel_charge(memcg, nr_pages);
+ return -ENOMEM;
+ }
+
+ page->mem_cgroup = memcg;
+
+ return 0;
+}
+
+/**
+ * memcg_kmem_charge: 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(struct page *page, gfp_t gfp, int order)
+{
+ struct mem_cgroup *memcg;
+ int ret = 0;
+
+ if (memcg_kmem_bypass())
+ return 0;
+
+ memcg = get_mem_cgroup_from_current();
+ if (!mem_cgroup_is_root(memcg)) {
+ ret = memcg_kmem_charge_memcg(page, gfp, order, memcg);
+ if (!ret)
+ __SetPageKmemcg(page);
+ }
+ css_put(&memcg->css);
+ return ret;
+}
+/**
+ * memcg_kmem_uncharge: uncharge a kmem page
+ * @page: page to uncharge
+ * @order: allocation order
+ */
+void memcg_kmem_uncharge(struct page *page, int order)
+{
+ struct mem_cgroup *memcg = page->mem_cgroup;
+ unsigned int nr_pages = 1 << order;
+
+ if (!memcg)
+ return;
+
+ VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page);
+
+ 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);
+
+ page->mem_cgroup = NULL;
+
+ /* slab pages do not have PageKmemcg flag set */
+ if (PageKmemcg(page))
+ __ClearPageKmemcg(page);
+
+ css_put_many(&memcg->css, nr_pages);
+}
+#endif /* CONFIG_MEMCG_KMEM */
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+
+/*
+ * Because tail pages are not marked as "used", set it. We're under
+ * zone_lru_lock and migration entries setup in all page mappings.
+ */
+void mem_cgroup_split_huge_fixup(struct page *head)
+{
+ int i;
+
+ if (mem_cgroup_disabled())
+ return;
+
+ for (i = 1; i < HPAGE_PMD_NR; i++)
+ head[i].mem_cgroup = head->mem_cgroup;
+
+ __mod_memcg_state(head->mem_cgroup, MEMCG_RSS_HUGE, -HPAGE_PMD_NR);
+}
+#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 >= 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;
+}
+
+/*
+ * Test whether @memcg has children, dead or alive. Note that this
+ * function doesn't care whether @memcg has use_hierarchy enabled and
+ * returns %true if there are child csses according to the cgroup
+ * hierarchy. Testing use_hierarchy is the caller's responsiblity.
+ */
+static inline bool memcg_has_children(struct mem_cgroup *memcg)
+{
+ bool ret;
+
+ rcu_read_lock();
+ ret = css_next_child(NULL, &memcg->css);
+ rcu_read_unlock();
+ return ret;
+}
+
+/*
+ * Reclaims as many pages from the given memcg as possible.
+ *
+ * Caller is responsible for holding css reference for memcg.
+ */
+static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
+{
+ int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+
+ /* we call try-to-free pages for make this cgroup empty */
+ lru_add_drain_all();
+
+ 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 mem_cgroup_from_css(css)->use_hierarchy;
+}
+
+static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
+ struct cftype *cft, u64 val)
+{
+ int retval = 0;
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+ struct mem_cgroup *parent_memcg = mem_cgroup_from_css(memcg->css.parent);
+
+ if (memcg->use_hierarchy == val)
+ return 0;
+
+ /*
+ * If parent's use_hierarchy is set, we can't make any modifications
+ * in the child subtrees. If it is unset, then the change can
+ * occur, provided the current cgroup has no children.
+ *
+ * For the root cgroup, parent_mem is NULL, we allow value to be
+ * set if there are no children.
+ */
+ if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
+ (val == 1 || val == 0)) {
+ if (!memcg_has_children(memcg))
+ memcg->use_hierarchy = val;
+ else
+ retval = -EBUSY;
+ } else
+ retval = -EINVAL;
+
+ return retval;
+}
+
+struct accumulated_stats {
+ unsigned long stat[MEMCG_NR_STAT];
+ unsigned long events[NR_VM_EVENT_ITEMS];
+ unsigned long lru_pages[NR_LRU_LISTS];
+ const unsigned int *stats_array;
+ const unsigned int *events_array;
+ int stats_size;
+ int events_size;
+};
+
+static void accumulate_memcg_tree(struct mem_cgroup *memcg,
+ struct accumulated_stats *acc)
+{
+ struct mem_cgroup *mi;
+ int i;
+
+ for_each_mem_cgroup_tree(mi, memcg) {
+ for (i = 0; i < acc->stats_size; i++)
+ acc->stat[i] += memcg_page_state(mi,
+ acc->stats_array ? acc->stats_array[i] : i);
+
+ for (i = 0; i < acc->events_size; i++)
+ acc->events[i] += memcg_sum_events(mi,
+ acc->events_array ? acc->events_array[i] : i);
+
+ for (i = 0; i < NR_LRU_LISTS; i++)
+ acc->lru_pages[i] +=
+ mem_cgroup_nr_lru_pages(mi, BIT(i));
+ }
+}
+
+static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
+{
+ unsigned long val = 0;
+
+ if (mem_cgroup_is_root(memcg)) {
+ struct mem_cgroup *iter;
+
+ for_each_mem_cgroup_tree(iter, memcg) {
+ val += memcg_page_state(iter, MEMCG_CACHE);
+ val += memcg_page_state(iter, MEMCG_RSS);
+ if (swap)
+ val += memcg_page_state(iter, 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();
+ }
+}
+
+#ifdef CONFIG_MEMCG_KMEM
+static int memcg_online_kmem(struct mem_cgroup *memcg)
+{
+ 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;
+
+ static_branch_inc(&memcg_kmem_enabled_key);
+ /*
+ * A memory cgroup is considered kmem-online as soon as it gets
+ * kmemcg_id. Setting the id after enabling static branching will
+ * guarantee no one starts accounting before all call sites are
+ * patched.
+ */
+ memcg->kmemcg_id = memcg_id;
+ memcg->kmem_state = KMEM_ONLINE;
+ INIT_LIST_HEAD(&memcg->kmem_caches);
+
+ 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;
+ /*
+ * Clear the online state before clearing memcg_caches array
+ * entries. The slab_mutex in memcg_deactivate_kmem_caches()
+ * guarantees that no cache will be created for this cgroup
+ * after we are done (see memcg_create_kmem_cache()).
+ */
+ memcg->kmem_state = KMEM_ALLOCATED;
+
+ memcg_deactivate_kmem_caches(memcg);
+
+ kmemcg_id = memcg->kmemcg_id;
+ BUG_ON(kmemcg_id < 0);
+
+ parent = parent_mem_cgroup(memcg);
+ if (!parent)
+ parent = root_mem_cgroup;
+
+ /*
+ * 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;
+ if (!memcg->use_hierarchy)
+ break;
+ }
+ 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);
+
+ if (memcg->kmem_state == KMEM_ALLOCATED) {
+ memcg_destroy_kmem_caches(memcg);
+ static_branch_dec(&memcg_kmem_enabled_key);
+ WARN_ON(page_counter_read(&memcg->kmem));
+ }
+}
+#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:
+ 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
+static int memcg_numa_stat_show(struct seq_file *m, void *v)
+{
+ struct numa_stat {
+ const char *name;
+ unsigned int lru_mask;
+ };
+
+ static const struct numa_stat stats[] = {
+ { "total", LRU_ALL },
+ { "file", LRU_ALL_FILE },
+ { "anon", LRU_ALL_ANON },
+ { "unevictable", BIT(LRU_UNEVICTABLE) },
+ };
+ const struct numa_stat *stat;
+ int nid;
+ unsigned long nr;
+ struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+
+ for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
+ nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask);
+ seq_printf(m, "%s=%lu", stat->name, nr);
+ for_each_node_state(nid, N_MEMORY) {
+ nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
+ stat->lru_mask);
+ seq_printf(m, " N%d=%lu", nid, nr);
+ }
+ seq_putc(m, '\n');
+ }
+
+ for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
+ struct mem_cgroup *iter;
+
+ nr = 0;
+ for_each_mem_cgroup_tree(iter, memcg)
+ nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask);
+ seq_printf(m, "hierarchical_%s=%lu", stat->name, nr);
+ for_each_node_state(nid, N_MEMORY) {
+ nr = 0;
+ for_each_mem_cgroup_tree(iter, memcg)
+ nr += mem_cgroup_node_nr_lru_pages(
+ iter, nid, stat->lru_mask);
+ seq_printf(m, " N%d=%lu", nid, nr);
+ }
+ seq_putc(m, '\n');
+ }
+
+ return 0;
+}
+#endif /* CONFIG_NUMA */
+
+/* Universal VM events cgroup1 shows, original sort order */
+static const unsigned int memcg1_events[] = {
+ PGPGIN,
+ PGPGOUT,
+ PGFAULT,
+ PGMAJFAULT,
+};
+
+static const char *const memcg1_event_names[] = {
+ "pgpgin",
+ "pgpgout",
+ "pgfault",
+ "pgmajfault",
+};
+
+static int memcg_stat_show(struct seq_file *m, void *v)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+ unsigned long memory, memsw;
+ struct mem_cgroup *mi;
+ unsigned int i;
+ struct accumulated_stats acc;
+
+ BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats));
+ BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
+
+ for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
+ if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
+ continue;
+ seq_printf(m, "%s %lu\n", memcg1_stat_names[i],
+ memcg_page_state(memcg, memcg1_stats[i]) *
+ PAGE_SIZE);
+ }
+
+ for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
+ seq_printf(m, "%s %lu\n", memcg1_event_names[i],
+ memcg_sum_events(memcg, memcg1_events[i]));
+
+ for (i = 0; i < NR_LRU_LISTS; i++)
+ seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
+ mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE);
+
+ /* Hierarchical information */
+ memory = memsw = PAGE_COUNTER_MAX;
+ for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) {
+ memory = min(memory, mi->memory.max);
+ memsw = min(memsw, 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);
+
+ memset(&acc, 0, sizeof(acc));
+ acc.stats_size = ARRAY_SIZE(memcg1_stats);
+ acc.stats_array = memcg1_stats;
+ acc.events_size = ARRAY_SIZE(memcg1_events);
+ acc.events_array = memcg1_events;
+ accumulate_memcg_tree(memcg, &acc);
+
+ for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
+ if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
+ continue;
+ seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i],
+ (u64)acc.stat[i] * PAGE_SIZE);
+ }
+
+ for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
+ seq_printf(m, "total_%s %llu\n", memcg1_event_names[i],
+ (u64)acc.events[i]);
+
+ for (i = 0; i < NR_LRU_LISTS; i++)
+ seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i],
+ (u64)acc.lru_pages[i] * PAGE_SIZE);
+
+#ifdef CONFIG_DEBUG_VM
+ {
+ pg_data_t *pgdat;
+ struct mem_cgroup_per_node *mz;
+ struct zone_reclaim_stat *rstat;
+ unsigned long recent_rotated[2] = {0, 0};
+ unsigned long recent_scanned[2] = {0, 0};
+
+ for_each_online_pgdat(pgdat) {
+ mz = mem_cgroup_nodeinfo(memcg, pgdat->node_id);
+ rstat = &mz->lruvec.reclaim_stat;
+
+ recent_rotated[0] += rstat->recent_rotated[0];
+ recent_rotated[1] += rstat->recent_rotated[1];
+ recent_scanned[0] += rstat->recent_scanned[0];
+ recent_scanned[1] += rstat->recent_scanned[1];
+ }
+ seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
+ seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
+ seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
+ seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
+ }
+#endif
+
+ return 0;
+}
+
+static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
+ struct cftype *cft)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+
+ return mem_cgroup_swappiness(memcg);
+}
+
+static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
+ struct cftype *cft, u64 val)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+
+ if (val > 100)
+ return -EINVAL;
+
+ if (css->parent)
+ memcg->swappiness = val;
+ else
+ vm_swappiness = val;
+
+ return 0;
+}
+
+static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
+{
+ struct mem_cgroup_threshold_ary *t;
+ unsigned long usage;
+ int i;
+
+ rcu_read_lock();
+ if (!swap)
+ t = rcu_dereference(memcg->thresholds.primary);
+ else
+ t = rcu_dereference(memcg->memsw_thresholds.primary);
+
+ if (!t)
+ goto unlock;
+
+ usage = mem_cgroup_usage(memcg, swap);
+
+ /*
+ * current_threshold points to threshold just below or equal to usage.
+ * If it's not true, a threshold was crossed after last
+ * call of __mem_cgroup_threshold().
+ */
+ i = t->current_threshold;
+
+ /*
+ * Iterate backward over array of thresholds starting from
+ * current_threshold and check if a threshold is crossed.
+ * If none of thresholds below usage is crossed, we read
+ * only one element of the array here.
+ */
+ for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
+ eventfd_signal(t->entries[i].eventfd, 1);
+
+ /* i = current_threshold + 1 */
+ i++;
+
+ /*
+ * Iterate forward over array of thresholds starting from
+ * current_threshold+1 and check if a threshold is crossed.
+ * If none of thresholds above usage is crossed, we read
+ * only one element of the array here.
+ */
+ for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
+ eventfd_signal(t->entries[i].eventfd, 1);
+
+ /* Update current_threshold */
+ t->current_threshold = i - 1;
+unlock:
+ rcu_read_unlock();
+}
+
+static void mem_cgroup_threshold(struct mem_cgroup *memcg)
+{
+ while (memcg) {
+ __mem_cgroup_threshold(memcg, false);
+ if (do_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(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
+ GFP_KERNEL);
+ if (!new) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+ new->size = size;
+
+ /* Copy thresholds (if any) to new array */
+ if (thresholds->primary) {
+ memcpy(new->entries, thresholds->primary->entries, (size - 1) *
+ sizeof(struct mem_cgroup_threshold));
+ }
+
+ /* Add new threshold */
+ new->entries[size - 1].eventfd = eventfd;
+ new->entries[size - 1].threshold = threshold;
+
+ /* Sort thresholds. Registering of new threshold isn't time-critical */
+ sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
+ compare_thresholds, NULL);
+
+ /* Find current threshold */
+ new->current_threshold = -1;
+ for (i = 0; i < size; i++) {
+ if (new->entries[i].threshold <= usage) {
+ /*
+ * new->current_threshold will not be used until
+ * rcu_assign_pointer(), so it's safe to increment
+ * it here.
+ */
+ ++new->current_threshold;
+ } else
+ break;
+ }
+
+ /* Free old spare buffer and save old primary buffer as spare */
+ kfree(thresholds->spare);
+ thresholds->spare = thresholds->primary;
+
+ rcu_assign_pointer(thresholds->primary, new);
+
+ /* To be sure that nobody uses thresholds */
+ synchronize_rcu();
+
+unlock:
+ mutex_unlock(&memcg->thresholds_lock);
+
+ return ret;
+}
+
+static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
+ struct eventfd_ctx *eventfd, const char *args)
+{
+ return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM);
+}
+
+static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg,
+ struct eventfd_ctx *eventfd, const char *args)
+{
+ return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP);
+}
+
+static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
+ struct eventfd_ctx *eventfd, enum res_type type)
+{
+ struct mem_cgroup_thresholds *thresholds;
+ struct mem_cgroup_threshold_ary *new;
+ unsigned long usage;
+ int i, j, size;
+
+ mutex_lock(&memcg->thresholds_lock);
+
+ if (type == _MEM) {
+ thresholds = &memcg->thresholds;
+ usage = mem_cgroup_usage(memcg, false);
+ } else if (type == _MEMSWAP) {
+ thresholds = &memcg->memsw_thresholds;
+ usage = mem_cgroup_usage(memcg, true);
+ } else
+ BUG();
+
+ if (!thresholds->primary)
+ goto unlock;
+
+ /* Check if a threshold crossed before removing */
+ __mem_cgroup_threshold(memcg, type == _MEMSWAP);
+
+ /* Calculate new number of threshold */
+ size = 0;
+ for (i = 0; i < thresholds->primary->size; i++) {
+ if (thresholds->primary->entries[i].eventfd != eventfd)
+ size++;
+ }
+
+ new = thresholds->spare;
+
+ /* Set thresholds array to NULL if we don't have thresholds */
+ if (!size) {
+ kfree(new);
+ new = NULL;
+ goto swap_buffers;
+ }
+
+ new->size = size;
+
+ /* Copy thresholds and find current threshold */
+ new->current_threshold = -1;
+ for (i = 0, j = 0; i < thresholds->primary->size; i++) {
+ if (thresholds->primary->entries[i].eventfd == eventfd)
+ continue;
+
+ new->entries[j] = thresholds->primary->entries[i];
+ if (new->entries[j].threshold <= usage) {
+ /*
+ * new->current_threshold will not be used
+ * until rcu_assign_pointer(), so it's safe to increment
+ * it here.
+ */
+ ++new->current_threshold;
+ }
+ j++;
+ }
+
+swap_buffers:
+ /* Swap primary and spare array */
+ thresholds->spare = thresholds->primary;
+
+ 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_css(seq_css(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
+
+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;
+}
+
+/**
+ * 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_page_state(memcg, NR_FILE_DIRTY);
+
+ /* this should eventually include NR_UNSTABLE_NFS */
+ *pwriteback = memcg_page_state(memcg, NR_WRITEBACK);
+ *pfilepages = mem_cgroup_nr_lru_pages(memcg, (1 << LRU_INACTIVE_FILE) |
+ (1 << LRU_ACTIVE_FILE));
+ *pheadroom = PAGE_COUNTER_MAX;
+
+ while ((parent = parent_mem_cgroup(memcg))) {
+ unsigned long ceiling = min(memcg->memory.max, memcg->high);
+ unsigned long used = page_counter_read(&memcg->memory);
+
+ *pheadroom = min(*pheadroom, ceiling - min(ceiling, used));
+ memcg = parent;
+ }
+}
+
+#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 = inode_permission(file_inode(cfile.file), MAY_READ);
+ if (ret < 0)
+ goto out_put_cfile;
+
+ /*
+ * Determine the event callbacks and set them in @event. This used
+ * to be done via struct cftype but cgroup core no longer knows
+ * about these events. The following is crude but the whole thing
+ * is for compatibility anyway.
+ *
+ * DO NOT ADD NEW FILES.
+ */
+ name = cfile.file->f_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_SLAB) || defined(CONFIG_SLUB_DEBUG)
+ {
+ .name = "kmem.slabinfo",
+ .seq_start = memcg_slab_start,
+ .seq_next = memcg_slab_next,
+ .seq_stop = memcg_slab_stop,
+ .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 oflline 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 mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n)
+{
+ VM_BUG_ON(atomic_read(&memcg->id.ref) <= 0);
+ atomic_add(n, &memcg->id.ref);
+}
+
+static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
+{
+ VM_BUG_ON(atomic_read(&memcg->id.ref) < n);
+ if (atomic_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_get(struct mem_cgroup *memcg)
+{
+ mem_cgroup_id_get_many(memcg, 1);
+}
+
+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_cpu = alloc_percpu(struct lruvec_stat);
+ if (!pn->lruvec_stat_cpu) {
+ 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);
+ 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->stat_cpu);
+ kfree(memcg);
+}
+
+static void mem_cgroup_free(struct mem_cgroup *memcg)
+{
+ memcg_wb_domain_exit(memcg);
+ __mem_cgroup_free(memcg);
+}
+
+static struct mem_cgroup *mem_cgroup_alloc(void)
+{
+ struct mem_cgroup *memcg;
+ size_t size;
+ int node;
+
+ size = sizeof(struct mem_cgroup);
+ size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
+
+ memcg = kzalloc(size, GFP_KERNEL);
+ if (!memcg)
+ return NULL;
+
+ memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL,
+ 1, MEM_CGROUP_ID_MAX,
+ GFP_KERNEL);
+ if (memcg->id.id < 0)
+ goto fail;
+
+ memcg->stat_cpu = alloc_percpu(struct mem_cgroup_stat_cpu);
+ if (!memcg->stat_cpu)
+ 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);
+ memcg->last_scanned_node = MAX_NUMNODES;
+ 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;
+#endif
+#ifdef CONFIG_CGROUP_WRITEBACK
+ INIT_LIST_HEAD(&memcg->cgwb_list);
+#endif
+ idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
+ return memcg;
+fail:
+ mem_cgroup_id_remove(memcg);
+ __mem_cgroup_free(memcg);
+ return NULL;
+}
+
+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;
+ long error = -ENOMEM;
+
+ memcg = mem_cgroup_alloc();
+ if (!memcg)
+ return ERR_PTR(error);
+
+ memcg->high = PAGE_COUNTER_MAX;
+ memcg->soft_limit = PAGE_COUNTER_MAX;
+ if (parent) {
+ memcg->swappiness = mem_cgroup_swappiness(parent);
+ memcg->oom_kill_disable = parent->oom_kill_disable;
+ }
+ if (parent && parent->use_hierarchy) {
+ memcg->use_hierarchy = true;
+ page_counter_init(&memcg->memory, &parent->memory);
+ page_counter_init(&memcg->swap, &parent->swap);
+ page_counter_init(&memcg->memsw, &parent->memsw);
+ 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->memsw, NULL);
+ page_counter_init(&memcg->kmem, NULL);
+ page_counter_init(&memcg->tcpmem, NULL);
+ /*
+ * Deeper hierachy with use_hierarchy == false doesn't make
+ * much sense so let cgroup subsystem know about this
+ * unfortunate state in our controller.
+ */
+ if (parent != root_mem_cgroup)
+ memory_cgrp_subsys.broken_hierarchy = true;
+ }
+
+ /* The following stuff does not apply to the root */
+ if (!parent) {
+ root_mem_cgroup = memcg;
+ return &memcg->css;
+ }
+
+ 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(-ENOMEM);
+}
+
+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 */
+ atomic_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);
+
+ 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);
+
+ 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->memsw, 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);
+ memcg->high = PAGE_COUNTER_MAX;
+ memcg->soft_limit = 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, true);
+
+ 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) || non_swap_entry(ent))
+ 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;
+ }
+
+ /*
+ * 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));
+ if (do_memsw_account())
+ 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)
+{
+ struct page *page = NULL;
+ struct address_space *mapping;
+ pgoff_t pgoff;
+
+ if (!vma->vm_file) /* anonymous vma */
+ return NULL;
+ if (!(mc.flags & MOVE_FILE))
+ return NULL;
+
+ mapping = vma->vm_file->f_mapping;
+ pgoff = linear_page_index(vma, addr);
+
+ /* page is moved even if it's not RSS of this task(page-faulted). */
+#ifdef CONFIG_SWAP
+ /* shmem/tmpfs may report page out on swap: account for that too. */
+ if (shmem_mapping(mapping)) {
+ page = find_get_entry(mapping, pgoff);
+ if (radix_tree_exceptional_entry(page)) {
+ swp_entry_t swp = radix_to_swp_entry(page);
+ if (do_memsw_account())
+ *entry = swp;
+ page = find_get_page(swap_address_space(swp),
+ swp_offset(swp));
+ }
+ } else
+ page = find_get_page(mapping, pgoff);
+#else
+ page = find_get_page(mapping, pgoff);
+#endif
+ return page;
+}
+
+/**
+ * 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)
+{
+ unsigned long flags;
+ unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
+ int ret;
+ bool anon;
+
+ 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->mem_cgroup of its source page while we change it.
+ */
+ ret = -EBUSY;
+ if (!trylock_page(page))
+ goto out;
+
+ ret = -EINVAL;
+ if (page->mem_cgroup != from)
+ goto out_unlock;
+
+ anon = PageAnon(page);
+
+ spin_lock_irqsave(&from->move_lock, flags);
+
+ if (!anon && page_mapped(page)) {
+ __mod_memcg_state(from, NR_FILE_MAPPED, -nr_pages);
+ __mod_memcg_state(to, NR_FILE_MAPPED, nr_pages);
+ }
+
+ /*
+ * move_lock grabbed above and caller set from->moving_account, so
+ * mod_memcg_page_state will serialize updates to PageDirty.
+ * So mapping should be stable for dirty pages.
+ */
+ if (!anon && PageDirty(page)) {
+ struct address_space *mapping = page_mapping(page);
+
+ if (mapping_cap_account_dirty(mapping)) {
+ __mod_memcg_state(from, NR_FILE_DIRTY, -nr_pages);
+ __mod_memcg_state(to, NR_FILE_DIRTY, nr_pages);
+ }
+ }
+
+ if (PageWriteback(page)) {
+ __mod_memcg_state(from, NR_WRITEBACK, -nr_pages);
+ __mod_memcg_state(to, NR_WRITEBACK, nr_pages);
+ }
+
+ /*
+ * It is safe to change page->mem_cgroup here because the page
+ * is referenced, charged, and isolated - we can't race with
+ * uncharging, charging, migration, or LRU putback.
+ */
+
+ /* caller should have done css_get */
+ page->mem_cgroup = to;
+ spin_unlock_irqrestore(&from->move_lock, flags);
+
+ ret = 0;
+
+ local_irq_disable();
+ mem_cgroup_charge_statistics(to, page, compound, nr_pages);
+ memcg_check_events(to, page);
+ mem_cgroup_charge_statistics(from, page, compound, -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_PUBLIC
+ * or 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->mem_cgroup == mc.from) {
+ ret = MC_TARGET_PAGE;
+ if (is_device_private_page(page) ||
+ is_device_public_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->mem_cgroup == mc.from) {
+ ret = MC_TARGET_PAGE;
+ if (target) {
+ get_page(page);
+ target->page = page;
+ }
+ }
+ return ret;
+}
+#else
+static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
+ unsigned long addr, pmd_t pmd, union mc_target *target)
+{
+ return MC_TARGET_NONE;
+}
+#endif
+
+static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
+ unsigned long addr, unsigned long end,
+ struct mm_walk *walk)
+{
+ struct vm_area_struct *vma = walk->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_PUBLIC or
+ * 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 unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
+{
+ unsigned long precharge;
+
+ struct mm_walk mem_cgroup_count_precharge_walk = {
+ .pmd_entry = mem_cgroup_count_precharge_pte_range,
+ .mm = mm,
+ };
+ down_read(&mm->mmap_sem);
+ walk_page_range(0, mm->highest_vm_end,
+ &mem_cgroup_count_precharge_walk);
+ up_read(&mm->mmap_sem);
+
+ precharge = mc.precharge;
+ mc.precharge = 0;
+
+ return precharge;
+}
+
+static int mem_cgroup_precharge_mc(struct mm_struct *mm)
+{
+ unsigned long precharge = mem_cgroup_count_precharge(mm);
+
+ VM_BUG_ON(mc.moving_task);
+ mc.moving_task = current;
+ return mem_cgroup_do_precharge(precharge);
+}
+
+/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
+static void __mem_cgroup_clear_mc(void)
+{
+ struct mem_cgroup *from = mc.from;
+ struct mem_cgroup *to = mc.to;
+
+ /* we must uncharge all the leftover precharges from mc.to */
+ if (mc.precharge) {
+ cancel_charge(mc.to, mc.precharge);
+ mc.precharge = 0;
+ }
+ /*
+ * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
+ * we must uncharge here.
+ */
+ if (mc.moved_charge) {
+ cancel_charge(mc.from, mc.moved_charge);
+ mc.moved_charge = 0;
+ }
+ /* we must fixup refcnts and charges */
+ if (mc.moved_swap) {
+ /* uncharge swap account from the old cgroup */
+ if (!mem_cgroup_is_root(mc.from))
+ page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
+
+ 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);
+
+ mem_cgroup_id_get_many(mc.to, mc.moved_swap);
+ css_put_many(&mc.to->css, 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;
+ /* fall through */
+ 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--;
+ /* we fixup refcnts and charges later. */
+ mc.moved_swap++;
+ }
+ break;
+ default:
+ break;
+ }
+ }
+ pte_unmap_unlock(pte - 1, ptl);
+ cond_resched();
+
+ if (addr != end) {
+ /*
+ * We have consumed all precharges we got in can_attach().
+ * We try charge one by one, but don't do any additional
+ * charges to mc.to if we have failed in charge once in attach()
+ * phase.
+ */
+ ret = mem_cgroup_do_precharge(1);
+ if (!ret)
+ goto retry;
+ }
+
+ return ret;
+}
+
+static void mem_cgroup_move_charge(void)
+{
+ struct mm_walk mem_cgroup_move_charge_walk = {
+ .pmd_entry = mem_cgroup_move_charge_pte_range,
+ .mm = mc.mm,
+ };
+
+ 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(!down_read_trylock(&mc.mm->mmap_sem))) {
+ /*
+ * Someone who are holding the mmap_sem might be waiting in
+ * waitq. So we cancel all extra charges, wake up all waiters,
+ * and retry. Because we cancel precharges, we might not be able
+ * to move enough charges, but moving charge is a best-effort
+ * feature anyway, so it wouldn't be a big problem.
+ */
+ __mem_cgroup_clear_mc();
+ cond_resched();
+ goto retry;
+ }
+ /*
+ * When we have consumed all precharges and failed in doing
+ * additional charge, the page walk just aborts.
+ */
+ walk_page_range(0, mc.mm->highest_vm_end, &mem_cgroup_move_charge_walk);
+
+ up_read(&mc.mm->mmap_sem);
+ 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
+
+/*
+ * Cgroup retains root cgroups across [un]mount cycles making it necessary
+ * to verify whether we're attached to the default hierarchy on each mount
+ * attempt.
+ */
+static void mem_cgroup_bind(struct cgroup_subsys_state *root_css)
+{
+ /*
+ * use_hierarchy is forced on the default hierarchy. cgroup core
+ * guarantees that @root doesn't have any children, so turning it
+ * on for the root memcg is enough.
+ */
+ if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
+ root_mem_cgroup->use_hierarchy = true;
+ else
+ root_mem_cgroup->use_hierarchy = false;
+}
+
+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)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+ unsigned long min = READ_ONCE(memcg->memory.min);
+
+ if (min == PAGE_COUNTER_MAX)
+ seq_puts(m, "max\n");
+ else
+ seq_printf(m, "%llu\n", (u64)min * PAGE_SIZE);
+
+ return 0;
+}
+
+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)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+ unsigned long low = READ_ONCE(memcg->memory.low);
+
+ if (low == PAGE_COUNTER_MAX)
+ seq_puts(m, "max\n");
+ else
+ seq_printf(m, "%llu\n", (u64)low * PAGE_SIZE);
+
+ return 0;
+}
+
+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)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+ unsigned long high = READ_ONCE(memcg->high);
+
+ if (high == PAGE_COUNTER_MAX)
+ seq_puts(m, "max\n");
+ else
+ seq_printf(m, "%llu\n", (u64)high * PAGE_SIZE);
+
+ return 0;
+}
+
+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 long nr_pages;
+ unsigned long high;
+ int err;
+
+ buf = strstrip(buf);
+ err = page_counter_memparse(buf, "max", &high);
+ if (err)
+ return err;
+
+ memcg->high = high;
+
+ nr_pages = page_counter_read(&memcg->memory);
+ if (nr_pages > high)
+ try_to_free_mem_cgroup_pages(memcg, nr_pages - high,
+ GFP_KERNEL, true);
+
+ memcg_wb_domain_size_changed(memcg);
+ return nbytes;
+}
+
+static int memory_max_show(struct seq_file *m, void *v)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+ unsigned long max = READ_ONCE(memcg->memory.max);
+
+ if (max == PAGE_COUNTER_MAX)
+ seq_puts(m, "max\n");
+ else
+ seq_printf(m, "%llu\n", (u64)max * PAGE_SIZE);
+
+ return 0;
+}
+
+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 = MEM_CGROUP_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)) {
+ err = -EINTR;
+ 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 int memory_events_show(struct seq_file *m, void *v)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+
+ seq_printf(m, "low %lu\n",
+ atomic_long_read(&memcg->memory_events[MEMCG_LOW]));
+ seq_printf(m, "high %lu\n",
+ atomic_long_read(&memcg->memory_events[MEMCG_HIGH]));
+ seq_printf(m, "max %lu\n",
+ atomic_long_read(&memcg->memory_events[MEMCG_MAX]));
+ seq_printf(m, "oom %lu\n",
+ atomic_long_read(&memcg->memory_events[MEMCG_OOM]));
+ seq_printf(m, "oom_kill %lu\n",
+ atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL]));
+
+ return 0;
+}
+
+static int memory_stat_show(struct seq_file *m, void *v)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+ struct accumulated_stats acc;
+ int i;
+
+ /*
+ * 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:
+ */
+
+ memset(&acc, 0, sizeof(acc));
+ acc.stats_size = MEMCG_NR_STAT;
+ acc.events_size = NR_VM_EVENT_ITEMS;
+ accumulate_memcg_tree(memcg, &acc);
+
+ seq_printf(m, "anon %llu\n",
+ (u64)acc.stat[MEMCG_RSS] * PAGE_SIZE);
+ seq_printf(m, "file %llu\n",
+ (u64)acc.stat[MEMCG_CACHE] * PAGE_SIZE);
+ seq_printf(m, "kernel_stack %llu\n",
+ (u64)acc.stat[MEMCG_KERNEL_STACK_KB] * 1024);
+ seq_printf(m, "slab %llu\n",
+ (u64)(acc.stat[NR_SLAB_RECLAIMABLE] +
+ acc.stat[NR_SLAB_UNRECLAIMABLE]) * PAGE_SIZE);
+ seq_printf(m, "sock %llu\n",
+ (u64)acc.stat[MEMCG_SOCK] * PAGE_SIZE);
+
+ seq_printf(m, "shmem %llu\n",
+ (u64)acc.stat[NR_SHMEM] * PAGE_SIZE);
+ seq_printf(m, "file_mapped %llu\n",
+ (u64)acc.stat[NR_FILE_MAPPED] * PAGE_SIZE);
+ seq_printf(m, "file_dirty %llu\n",
+ (u64)acc.stat[NR_FILE_DIRTY] * PAGE_SIZE);
+ seq_printf(m, "file_writeback %llu\n",
+ (u64)acc.stat[NR_WRITEBACK] * PAGE_SIZE);
+
+ for (i = 0; i < NR_LRU_LISTS; i++)
+ seq_printf(m, "%s %llu\n", mem_cgroup_lru_names[i],
+ (u64)acc.lru_pages[i] * PAGE_SIZE);
+
+ seq_printf(m, "slab_reclaimable %llu\n",
+ (u64)acc.stat[NR_SLAB_RECLAIMABLE] * PAGE_SIZE);
+ seq_printf(m, "slab_unreclaimable %llu\n",
+ (u64)acc.stat[NR_SLAB_UNRECLAIMABLE] * PAGE_SIZE);
+
+ /* Accumulated memory events */
+
+ seq_printf(m, "pgfault %lu\n", acc.events[PGFAULT]);
+ seq_printf(m, "pgmajfault %lu\n", acc.events[PGMAJFAULT]);
+
+ seq_printf(m, "pgrefill %lu\n", acc.events[PGREFILL]);
+ seq_printf(m, "pgscan %lu\n", acc.events[PGSCAN_KSWAPD] +
+ acc.events[PGSCAN_DIRECT]);
+ seq_printf(m, "pgsteal %lu\n", acc.events[PGSTEAL_KSWAPD] +
+ acc.events[PGSTEAL_DIRECT]);
+ seq_printf(m, "pgactivate %lu\n", acc.events[PGACTIVATE]);
+ seq_printf(m, "pgdeactivate %lu\n", acc.events[PGDEACTIVATE]);
+ seq_printf(m, "pglazyfree %lu\n", acc.events[PGLAZYFREE]);
+ seq_printf(m, "pglazyfreed %lu\n", acc.events[PGLAZYFREED]);
+
+ seq_printf(m, "workingset_refault %lu\n",
+ acc.stat[WORKINGSET_REFAULT]);
+ seq_printf(m, "workingset_activate %lu\n",
+ acc.stat[WORKINGSET_ACTIVATE]);
+ seq_printf(m, "workingset_nodereclaim %lu\n",
+ acc.stat[WORKINGSET_NODERECLAIM]);
+
+ return 0;
+}
+
+static int memory_oom_group_show(struct seq_file *m, void *v)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(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 = "stat",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = memory_stat_show,
+ },
+ {
+ .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,
+ .bind = mem_cgroup_bind,
+ .dfl_cftypes = memory_files,
+ .legacy_cftypes = mem_cgroup_legacy_files,
+ .early_init = 0,
+};
+
+/**
+ * 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.
+ *
+ * Returns one of the following:
+ * MEMCG_PROT_NONE: cgroup memory is not protected
+ * MEMCG_PROT_LOW: cgroup memory is protected as long there is
+ * an unprotected supply of reclaimable memory from other cgroups.
+ * MEMCG_PROT_MIN: cgroup memory is protected
+ *
+ * @root is exclusive; it is never protected when looked at directly
+ *
+ * To provide a proper hierarchical behavior, effective memory.min/low values
+ * are used. Below is the description of how effective memory.low is calculated.
+ * Effective memory.min values is calculated in the same way.
+ *
+ * Effective memory.low is always equal or less than the original memory.low.
+ * If there is no memory.low overcommittment (which is always true for
+ * top-level memory cgroups), these two values are equal.
+ * Otherwise, it's a part of parent's effective memory.low,
+ * calculated as a cgroup's memory.low usage divided by sum of sibling's
+ * memory.low usages, where memory.low usage is the size of actually
+ * protected memory.
+ *
+ * low_usage
+ * elow = min( memory.low, parent->elow * ------------------ ),
+ * siblings_low_usage
+ *
+ * | memory.current, if memory.current < memory.low
+ * low_usage = |
+ | 0, otherwise.
+ *
+ *
+ * Such definition of the effective memory.low provides the expected
+ * hierarchical behavior: parent's memory.low value is limiting
+ * children, unprotected memory is reclaimed first and cgroups,
+ * which are not using their guarantee do not affect actual memory
+ * distribution.
+ *
+ * For example, if there are memcgs A, A/B, A/C, A/D and A/E:
+ *
+ * A A/memory.low = 2G, A/memory.current = 6G
+ * //\\
+ * BC DE B/memory.low = 3G B/memory.current = 2G
+ * C/memory.low = 1G C/memory.current = 2G
+ * D/memory.low = 0 D/memory.current = 2G
+ * E/memory.low = 10G E/memory.current = 0
+ *
+ * and the memory pressure is applied, the following memory distribution
+ * is expected (approximately):
+ *
+ * A/memory.current = 2G
+ *
+ * B/memory.current = 1.3G
+ * C/memory.current = 0.6G
+ * D/memory.current = 0
+ * E/memory.current = 0
+ *
+ * These calculations require constant tracking of the actual low usages
+ * (see propagate_protected_usage()), as well as recursive calculation of
+ * effective memory.low values. But as we do call mem_cgroup_protected()
+ * path for each memory cgroup top-down from the reclaim,
+ * it's possible to optimize this part, and save calculated elow
+ * for next usage. This part is intentionally racy, but it's ok,
+ * as memory.low is a best-effort mechanism.
+ */
+enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root,
+ struct mem_cgroup *memcg)
+{
+ struct mem_cgroup *parent;
+ unsigned long emin, parent_emin;
+ unsigned long elow, parent_elow;
+ unsigned long usage;
+
+ if (mem_cgroup_disabled())
+ return MEMCG_PROT_NONE;
+
+ if (!root)
+ root = root_mem_cgroup;
+ if (memcg == root)
+ return MEMCG_PROT_NONE;
+
+ usage = page_counter_read(&memcg->memory);
+ if (!usage)
+ return MEMCG_PROT_NONE;
+
+ emin = memcg->memory.min;
+ elow = memcg->memory.low;
+
+ parent = parent_mem_cgroup(memcg);
+ /* No parent means a non-hierarchical mode on v1 memcg */
+ if (!parent)
+ return MEMCG_PROT_NONE;
+
+ if (parent == root)
+ goto exit;
+
+ parent_emin = READ_ONCE(parent->memory.emin);
+ emin = min(emin, parent_emin);
+ if (emin && parent_emin) {
+ unsigned long min_usage, siblings_min_usage;
+
+ min_usage = min(usage, memcg->memory.min);
+ siblings_min_usage = atomic_long_read(
+ &parent->memory.children_min_usage);
+
+ if (min_usage && siblings_min_usage)
+ emin = min(emin, parent_emin * min_usage /
+ siblings_min_usage);
+ }
+
+ parent_elow = READ_ONCE(parent->memory.elow);
+ elow = min(elow, parent_elow);
+ if (elow && parent_elow) {
+ unsigned long low_usage, siblings_low_usage;
+
+ low_usage = min(usage, memcg->memory.low);
+ siblings_low_usage = atomic_long_read(
+ &parent->memory.children_low_usage);
+
+ if (low_usage && siblings_low_usage)
+ elow = min(elow, parent_elow * low_usage /
+ siblings_low_usage);
+ }
+
+exit:
+ memcg->memory.emin = emin;
+ memcg->memory.elow = elow;
+
+ if (usage <= emin)
+ return MEMCG_PROT_MIN;
+ else if (usage <= elow)
+ return MEMCG_PROT_LOW;
+ else
+ return MEMCG_PROT_NONE;
+}
+
+/**
+ * mem_cgroup_try_charge - try charging a page
+ * @page: page to charge
+ * @mm: mm context of the victim
+ * @gfp_mask: reclaim mode
+ * @memcgp: charged memcg return
+ * @compound: charge the page as compound or small page
+ *
+ * Try to charge @page to the memcg that @mm belongs to, reclaiming
+ * pages according to @gfp_mask if necessary.
+ *
+ * Returns 0 on success, with *@memcgp pointing to the charged memcg.
+ * Otherwise, an error code is returned.
+ *
+ * After page->mapping has been set up, the caller must finalize the
+ * charge with mem_cgroup_commit_charge(). Or abort the transaction
+ * with mem_cgroup_cancel_charge() in case page instantiation fails.
+ */
+int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
+ gfp_t gfp_mask, struct mem_cgroup **memcgp,
+ bool compound)
+{
+ struct mem_cgroup *memcg = NULL;
+ unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
+ int ret = 0;
+
+ if (mem_cgroup_disabled())
+ goto out;
+
+ if (PageSwapCache(page)) {
+ /*
+ * Every swap fault against a single page tries to charge the
+ * page, bail as early as possible. shmem_unuse() encounters
+ * already charged pages, too. The USED bit is protected by
+ * the page lock, which serializes swap cache removal, which
+ * in turn serializes uncharging.
+ */
+ VM_BUG_ON_PAGE(!PageLocked(page), page);
+ if (compound_head(page)->mem_cgroup)
+ goto out;
+
+ if (do_swap_account) {
+ swp_entry_t ent = { .val = page_private(page), };
+ unsigned short 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);
+
+ css_put(&memcg->css);
+out:
+ *memcgp = memcg;
+ return ret;
+}
+
+int mem_cgroup_try_charge_delay(struct page *page, struct mm_struct *mm,
+ gfp_t gfp_mask, struct mem_cgroup **memcgp,
+ bool compound)
+{
+ struct mem_cgroup *memcg;
+ int ret;
+
+ ret = mem_cgroup_try_charge(page, mm, gfp_mask, memcgp, compound);
+ memcg = *memcgp;
+ mem_cgroup_throttle_swaprate(memcg, page_to_nid(page), gfp_mask);
+ return ret;
+}
+
+/**
+ * mem_cgroup_commit_charge - commit a page charge
+ * @page: page to charge
+ * @memcg: memcg to charge the page to
+ * @lrucare: page might be on LRU already
+ * @compound: charge the page as compound or small page
+ *
+ * Finalize a charge transaction started by mem_cgroup_try_charge(),
+ * after page->mapping has been set up. This must happen atomically
+ * as part of the page instantiation, i.e. under the page table lock
+ * for anonymous pages, under the page lock for page and swap cache.
+ *
+ * In addition, the page must not be on the LRU during the commit, to
+ * prevent racing with task migration. If it might be, use @lrucare.
+ *
+ * Use mem_cgroup_cancel_charge() to cancel the transaction instead.
+ */
+void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,
+ bool lrucare, bool compound)
+{
+ unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
+
+ VM_BUG_ON_PAGE(!page->mapping, page);
+ VM_BUG_ON_PAGE(PageLRU(page) && !lrucare, page);
+
+ if (mem_cgroup_disabled())
+ return;
+ /*
+ * Swap faults will attempt to charge the same page multiple
+ * times. But reuse_swap_page() might have removed the page
+ * from swapcache already, so we can't check PageSwapCache().
+ */
+ if (!memcg)
+ return;
+
+ commit_charge(page, memcg, lrucare);
+
+ local_irq_disable();
+ mem_cgroup_charge_statistics(memcg, page, compound, nr_pages);
+ memcg_check_events(memcg, page);
+ local_irq_enable();
+
+ if (do_memsw_account() && PageSwapCache(page)) {
+ swp_entry_t entry = { .val = page_private(page) };
+ /*
+ * The swap entry might not get freed for a long time,
+ * let's not wait for it. The page already received a
+ * memory+swap charge, drop the swap entry duplicate.
+ */
+ mem_cgroup_uncharge_swap(entry, nr_pages);
+ }
+}
+
+/**
+ * mem_cgroup_cancel_charge - cancel a page charge
+ * @page: page to charge
+ * @memcg: memcg to charge the page to
+ * @compound: charge the page as compound or small page
+ *
+ * Cancel a charge transaction started by mem_cgroup_try_charge().
+ */
+void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg,
+ bool compound)
+{
+ unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
+
+ if (mem_cgroup_disabled())
+ return;
+ /*
+ * Swap faults will attempt to charge the same page multiple
+ * times. But reuse_swap_page() might have removed the page
+ * from swapcache already, so we can't check PageSwapCache().
+ */
+ if (!memcg)
+ return;
+
+ cancel_charge(memcg, nr_pages);
+}
+
+struct uncharge_gather {
+ struct mem_cgroup *memcg;
+ unsigned long pgpgout;
+ unsigned long nr_anon;
+ unsigned long nr_file;
+ unsigned long nr_kmem;
+ unsigned long nr_huge;
+ unsigned long nr_shmem;
+ 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 nr_pages = ug->nr_anon + ug->nr_file + ug->nr_kmem;
+ unsigned long flags;
+
+ if (!mem_cgroup_is_root(ug->memcg)) {
+ page_counter_uncharge(&ug->memcg->memory, nr_pages);
+ if (do_memsw_account())
+ page_counter_uncharge(&ug->memcg->memsw, 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);
+ __mod_memcg_state(ug->memcg, MEMCG_RSS, -ug->nr_anon);
+ __mod_memcg_state(ug->memcg, MEMCG_CACHE, -ug->nr_file);
+ __mod_memcg_state(ug->memcg, MEMCG_RSS_HUGE, -ug->nr_huge);
+ __mod_memcg_state(ug->memcg, NR_SHMEM, -ug->nr_shmem);
+ __count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
+ __this_cpu_add(ug->memcg->stat_cpu->nr_page_events, nr_pages);
+ memcg_check_events(ug->memcg, ug->dummy_page);
+ local_irq_restore(flags);
+
+ if (!mem_cgroup_is_root(ug->memcg))
+ css_put_many(&ug->memcg->css, nr_pages);
+}
+
+static void uncharge_page(struct page *page, struct uncharge_gather *ug)
+{
+ VM_BUG_ON_PAGE(PageLRU(page), page);
+ VM_BUG_ON_PAGE(page_count(page) && !is_zone_device_page(page) &&
+ !PageHWPoison(page) , page);
+
+ if (!page->mem_cgroup)
+ return;
+
+ /*
+ * Nobody should be changing or seriously looking at
+ * page->mem_cgroup at this point, we have fully
+ * exclusive access to the page.
+ */
+
+ if (ug->memcg != page->mem_cgroup) {
+ if (ug->memcg) {
+ uncharge_batch(ug);
+ uncharge_gather_clear(ug);
+ }
+ ug->memcg = page->mem_cgroup;
+ }
+
+ if (!PageKmemcg(page)) {
+ unsigned int nr_pages = 1;
+
+ if (PageTransHuge(page)) {
+ nr_pages <<= compound_order(page);
+ ug->nr_huge += nr_pages;
+ }
+ if (PageAnon(page))
+ ug->nr_anon += nr_pages;
+ else {
+ ug->nr_file += nr_pages;
+ if (PageSwapBacked(page))
+ ug->nr_shmem += nr_pages;
+ }
+ ug->pgpgout++;
+ } else {
+ ug->nr_kmem += 1 << compound_order(page);
+ __ClearPageKmemcg(page);
+ }
+
+ ug->dummy_page = page;
+ page->mem_cgroup = NULL;
+}
+
+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_try_charge() and
+ * mem_cgroup_commit_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->mem_cgroup)
+ 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_try_charge() and mem_cgroup_commit_charge().
+ */
+void mem_cgroup_uncharge_list(struct list_head *page_list)
+{
+ if (mem_cgroup_disabled())
+ return;
+
+ if (!list_empty(page_list))
+ uncharge_list(page_list);
+}
+
+/**
+ * mem_cgroup_migrate - 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;
+ bool compound;
+ 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 (newpage->mem_cgroup)
+ return;
+
+ /* Swapcache readahead pages can get replaced before being charged */
+ memcg = oldpage->mem_cgroup;
+ if (!memcg)
+ return;
+
+ /* Force-charge the new page. The old one will be freed soon */
+ compound = PageTransHuge(newpage);
+ nr_pages = compound ? hpage_nr_pages(newpage) : 1;
+
+ page_counter_charge(&memcg->memory, nr_pages);
+ if (do_memsw_account())
+ page_counter_charge(&memcg->memsw, nr_pages);
+ css_get_many(&memcg->css, nr_pages);
+
+ commit_charge(newpage, memcg, false);
+
+ local_irq_save(flags);
+ mem_cgroup_charge_statistics(memcg, newpage, compound, 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;
+
+ /*
+ * Socket cloning can throw us here with sk_memcg already
+ * filled. It won't however, necessarily happen from
+ * process context. So the test for root memcg given
+ * the current task's memcg won't help us in this case.
+ *
+ * Respecting the original socket's memcg is a better
+ * decision in this case.
+ */
+ if (sk->sk_memcg) {
+ css_get(&sk->sk_memcg->css);
+ 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_online(&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;
+
+#ifdef CONFIG_MEMCG_KMEM
+ /*
+ * Kmem cache creation is mostly done with the slab_mutex held,
+ * so use a workqueue with limited concurrency to avoid stalling
+ * all worker threads in case lots of cgroups are created and
+ * destroyed simultaneously.
+ */
+ memcg_kmem_cache_wq = alloc_workqueue("memcg_kmem_cache", 0, 1);
+ BUG_ON(!memcg_kmem_cache_wq);
+#endif
+
+ 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 (!atomic_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 (!do_memsw_account())
+ return;
+
+ memcg = page->mem_cgroup;
+
+ /* Readahead page, never charged */
+ 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 = hpage_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->mem_cgroup = NULL;
+
+ if (!mem_cgroup_is_root(memcg))
+ page_counter_uncharge(&memcg->memory, nr_entries);
+
+ if (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, PageTransHuge(page),
+ -nr_entries);
+ memcg_check_events(memcg, page);
+
+ if (!mem_cgroup_is_root(memcg))
+ css_put_many(&memcg->css, nr_entries);
+}
+
+/**
+ * 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 = hpage_nr_pages(page);
+ struct page_counter *counter;
+ struct mem_cgroup *memcg;
+ unsigned short oldid;
+
+ if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) || !do_swap_account)
+ return 0;
+
+ memcg = page->mem_cgroup;
+
+ /* Readahead page, never charged */
+ if (!memcg)
+ return 0;
+
+ if (!entry.val) {
+ memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
+ return 0;
+ }
+
+ memcg = mem_cgroup_id_get_online(memcg);
+
+ if (!mem_cgroup_is_root(memcg) &&
+ !page_counter_try_charge(&memcg->swap, nr_pages, &counter)) {
+ memcg_memory_event(memcg, MEMCG_SWAP_MAX);
+ memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
+ mem_cgroup_id_put(memcg);
+ return -ENOMEM;
+ }
+
+ /* 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;
+
+ if (!do_swap_account)
+ return;
+
+ id = swap_cgroup_record(entry, 0, nr_pages);
+ rcu_read_lock();
+ memcg = mem_cgroup_from_id(id);
+ if (memcg) {
+ if (!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 (!do_swap_account || !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 (!do_swap_account || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
+ return false;
+
+ memcg = page->mem_cgroup;
+ if (!memcg)
+ return false;
+
+ for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg))
+ if (page_counter_read(&memcg->swap) * 2 >= memcg->swap.max)
+ return true;
+
+ return false;
+}
+
+/* for remember boot option*/
+#ifdef CONFIG_MEMCG_SWAP_ENABLED
+static int really_do_swap_account __initdata = 1;
+#else
+static int really_do_swap_account __initdata;
+#endif
+
+static int __init enable_swap_account(char *s)
+{
+ if (!strcmp(s, "1"))
+ really_do_swap_account = 1;
+ else if (!strcmp(s, "0"))
+ really_do_swap_account = 0;
+ return 1;
+}
+__setup("swapaccount=", enable_swap_account);
+
+static 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_max_show(struct seq_file *m, void *v)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+ unsigned long max = READ_ONCE(memcg->swap.max);
+
+ if (max == PAGE_COUNTER_MAX)
+ seq_puts(m, "max\n");
+ else
+ seq_printf(m, "%llu\n", (u64)max * PAGE_SIZE);
+
+ return 0;
+}
+
+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_css(seq_css(m));
+
+ 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.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_cgroup_files[] = {
+ {
+ .name = "memsw.usage_in_bytes",
+ .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
+ .read_u64 = mem_cgroup_read_u64,
+ },
+ {
+ .name = "memsw.max_usage_in_bytes",
+ .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
+ .write = mem_cgroup_reset,
+ .read_u64 = mem_cgroup_read_u64,
+ },
+ {
+ .name = "memsw.limit_in_bytes",
+ .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
+ .write = mem_cgroup_write,
+ .read_u64 = mem_cgroup_read_u64,
+ },
+ {
+ .name = "memsw.failcnt",
+ .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
+ .write = mem_cgroup_reset,
+ .read_u64 = mem_cgroup_read_u64,
+ },
+ { }, /* terminate */
+};
+
+static int __init mem_cgroup_swap_init(void)
+{
+ if (!mem_cgroup_disabled() && really_do_swap_account) {
+ do_swap_account = 1;
+ WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys,
+ swap_files));
+ WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys,
+ memsw_cgroup_files));
+ }
+ return 0;
+}
+subsys_initcall(mem_cgroup_swap_init);
+
+#endif /* CONFIG_MEMCG_SWAP */