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-rw-r--r--mm/memcontrol.c7914
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diff --git a/mm/memcontrol.c b/mm/memcontrol.c
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--- /dev/null
+++ b/mm/memcontrol.c
@@ -0,0 +1,7914 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* memcontrol.c - Memory Controller
+ *
+ * Copyright IBM Corporation, 2007
+ * Author Balbir Singh <balbir@linux.vnet.ibm.com>
+ *
+ * Copyright 2007 OpenVZ SWsoft Inc
+ * Author: Pavel Emelianov <xemul@openvz.org>
+ *
+ * Memory thresholds
+ * Copyright (C) 2009 Nokia Corporation
+ * Author: Kirill A. Shutemov
+ *
+ * Kernel Memory Controller
+ * Copyright (C) 2012 Parallels Inc. and Google Inc.
+ * Authors: Glauber Costa and Suleiman Souhlal
+ *
+ * Native page reclaim
+ * Charge lifetime sanitation
+ * Lockless page tracking & accounting
+ * Unified hierarchy configuration model
+ * Copyright (C) 2015 Red Hat, Inc., Johannes Weiner
+ *
+ * Per memcg lru locking
+ * Copyright (C) 2020 Alibaba, Inc, Alex Shi
+ */
+
+#include <linux/page_counter.h>
+#include <linux/memcontrol.h>
+#include <linux/cgroup.h>
+#include <linux/pagewalk.h>
+#include <linux/sched/mm.h>
+#include <linux/shmem_fs.h>
+#include <linux/hugetlb.h>
+#include <linux/pagemap.h>
+#include <linux/vm_event_item.h>
+#include <linux/smp.h>
+#include <linux/page-flags.h>
+#include <linux/backing-dev.h>
+#include <linux/bit_spinlock.h>
+#include <linux/rcupdate.h>
+#include <linux/limits.h>
+#include <linux/export.h>
+#include <linux/mutex.h>
+#include <linux/rbtree.h>
+#include <linux/slab.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+#include <linux/spinlock.h>
+#include <linux/eventfd.h>
+#include <linux/poll.h>
+#include <linux/sort.h>
+#include <linux/fs.h>
+#include <linux/seq_file.h>
+#include <linux/vmpressure.h>
+#include <linux/memremap.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/resume_user_mode.h>
+#include <linux/psi.h>
+#include <linux/seq_buf.h>
+#include <linux/sched/isolation.h>
+#include "internal.h"
+#include <net/sock.h>
+#include <net/ip.h>
+#include "slab.h"
+#include "swap.h"
+
+#include <linux/uaccess.h>
+
+#include <trace/events/vmscan.h>
+
+struct cgroup_subsys memory_cgrp_subsys __read_mostly;
+EXPORT_SYMBOL(memory_cgrp_subsys);
+
+struct mem_cgroup *root_mem_cgroup __read_mostly;
+
+/* Active memory cgroup to use from an interrupt context */
+DEFINE_PER_CPU(struct mem_cgroup *, int_active_memcg);
+EXPORT_PER_CPU_SYMBOL_GPL(int_active_memcg);
+
+/* Socket memory accounting disabled? */
+static bool cgroup_memory_nosocket __ro_after_init;
+
+/* Kernel memory accounting disabled? */
+static bool cgroup_memory_nokmem __ro_after_init;
+
+/* BPF memory accounting disabled? */
+static bool cgroup_memory_nobpf __ro_after_init;
+
+#ifdef CONFIG_CGROUP_WRITEBACK
+static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq);
+#endif
+
+/* Whether legacy memory+swap accounting is active */
+static bool do_memsw_account(void)
+{
+ return !cgroup_subsys_on_dfl(memory_cgrp_subsys);
+}
+
+#define THRESHOLDS_EVENTS_TARGET 128
+#define SOFTLIMIT_EVENTS_TARGET 1024
+
+/*
+ * Cgroups above their limits are maintained in a RB-Tree, independent of
+ * their hierarchy representation
+ */
+
+struct mem_cgroup_tree_per_node {
+ struct rb_root rb_root;
+ struct rb_node *rb_rightmost;
+ spinlock_t lock;
+};
+
+struct mem_cgroup_tree {
+ struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
+};
+
+static struct mem_cgroup_tree soft_limit_tree __read_mostly;
+
+/* for OOM */
+struct mem_cgroup_eventfd_list {
+ struct list_head list;
+ struct eventfd_ctx *eventfd;
+};
+
+/*
+ * cgroup_event represents events which userspace want to receive.
+ */
+struct mem_cgroup_event {
+ /*
+ * memcg which the event belongs to.
+ */
+ struct mem_cgroup *memcg;
+ /*
+ * eventfd to signal userspace about the event.
+ */
+ struct eventfd_ctx *eventfd;
+ /*
+ * Each of these stored in a list by the cgroup.
+ */
+ struct list_head list;
+ /*
+ * register_event() callback will be used to add new userspace
+ * waiter for changes related to this event. Use eventfd_signal()
+ * on eventfd to send notification to userspace.
+ */
+ int (*register_event)(struct mem_cgroup *memcg,
+ struct eventfd_ctx *eventfd, const char *args);
+ /*
+ * unregister_event() callback will be called when userspace closes
+ * the eventfd or on cgroup removing. This callback must be set,
+ * if you want provide notification functionality.
+ */
+ void (*unregister_event)(struct mem_cgroup *memcg,
+ struct eventfd_ctx *eventfd);
+ /*
+ * All fields below needed to unregister event when
+ * userspace closes eventfd.
+ */
+ poll_table pt;
+ wait_queue_head_t *wqh;
+ wait_queue_entry_t wait;
+ struct work_struct remove;
+};
+
+static void mem_cgroup_threshold(struct mem_cgroup *memcg);
+static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
+
+/* Stuffs for move charges at task migration. */
+/*
+ * Types of charges to be moved.
+ */
+#define MOVE_ANON 0x1U
+#define MOVE_FILE 0x2U
+#define MOVE_MASK (MOVE_ANON | MOVE_FILE)
+
+/* "mc" and its members are protected by cgroup_mutex */
+static struct move_charge_struct {
+ spinlock_t lock; /* for from, to */
+ struct mm_struct *mm;
+ struct mem_cgroup *from;
+ struct mem_cgroup *to;
+ unsigned long flags;
+ unsigned long precharge;
+ unsigned long moved_charge;
+ unsigned long moved_swap;
+ struct task_struct *moving_task; /* a task moving charges */
+ wait_queue_head_t waitq; /* a waitq for other context */
+} mc = {
+ .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
+ .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
+};
+
+/*
+ * Maximum loops in mem_cgroup_soft_reclaim(), used for soft
+ * limit reclaim to prevent infinite loops, if they ever occur.
+ */
+#define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
+#define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
+
+/* for encoding cft->private value on file */
+enum res_type {
+ _MEM,
+ _MEMSWAP,
+ _KMEM,
+ _TCP,
+};
+
+#define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
+#define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
+#define MEMFILE_ATTR(val) ((val) & 0xffff)
+
+/*
+ * Iteration constructs for visiting all cgroups (under a tree). If
+ * loops are exited prematurely (break), mem_cgroup_iter_break() must
+ * be used for reference counting.
+ */
+#define for_each_mem_cgroup_tree(iter, root) \
+ for (iter = mem_cgroup_iter(root, NULL, NULL); \
+ iter != NULL; \
+ iter = mem_cgroup_iter(root, iter, NULL))
+
+#define for_each_mem_cgroup(iter) \
+ for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
+ iter != NULL; \
+ iter = mem_cgroup_iter(NULL, iter, NULL))
+
+static inline bool task_is_dying(void)
+{
+ return tsk_is_oom_victim(current) || fatal_signal_pending(current) ||
+ (current->flags & PF_EXITING);
+}
+
+/* Some nice accessors for the vmpressure. */
+struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg)
+{
+ if (!memcg)
+ memcg = root_mem_cgroup;
+ return &memcg->vmpressure;
+}
+
+struct mem_cgroup *vmpressure_to_memcg(struct vmpressure *vmpr)
+{
+ return container_of(vmpr, struct mem_cgroup, vmpressure);
+}
+
+#ifdef CONFIG_MEMCG_KMEM
+static DEFINE_SPINLOCK(objcg_lock);
+
+bool mem_cgroup_kmem_disabled(void)
+{
+ return cgroup_memory_nokmem;
+}
+
+static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg,
+ unsigned int nr_pages);
+
+static void obj_cgroup_release(struct percpu_ref *ref)
+{
+ struct obj_cgroup *objcg = container_of(ref, struct obj_cgroup, refcnt);
+ unsigned int nr_bytes;
+ unsigned int nr_pages;
+ unsigned long flags;
+
+ /*
+ * At this point all allocated objects are freed, and
+ * objcg->nr_charged_bytes can't have an arbitrary byte value.
+ * However, it can be PAGE_SIZE or (x * PAGE_SIZE).
+ *
+ * The following sequence can lead to it:
+ * 1) CPU0: objcg == stock->cached_objcg
+ * 2) CPU1: we do a small allocation (e.g. 92 bytes),
+ * PAGE_SIZE bytes are charged
+ * 3) CPU1: a process from another memcg is allocating something,
+ * the stock if flushed,
+ * objcg->nr_charged_bytes = PAGE_SIZE - 92
+ * 5) CPU0: we do release this object,
+ * 92 bytes are added to stock->nr_bytes
+ * 6) CPU0: stock is flushed,
+ * 92 bytes are added to objcg->nr_charged_bytes
+ *
+ * In the result, nr_charged_bytes == PAGE_SIZE.
+ * This page will be uncharged in obj_cgroup_release().
+ */
+ nr_bytes = atomic_read(&objcg->nr_charged_bytes);
+ WARN_ON_ONCE(nr_bytes & (PAGE_SIZE - 1));
+ nr_pages = nr_bytes >> PAGE_SHIFT;
+
+ if (nr_pages)
+ obj_cgroup_uncharge_pages(objcg, nr_pages);
+
+ spin_lock_irqsave(&objcg_lock, flags);
+ list_del(&objcg->list);
+ spin_unlock_irqrestore(&objcg_lock, flags);
+
+ percpu_ref_exit(ref);
+ kfree_rcu(objcg, rcu);
+}
+
+static struct obj_cgroup *obj_cgroup_alloc(void)
+{
+ struct obj_cgroup *objcg;
+ int ret;
+
+ objcg = kzalloc(sizeof(struct obj_cgroup), GFP_KERNEL);
+ if (!objcg)
+ return NULL;
+
+ ret = percpu_ref_init(&objcg->refcnt, obj_cgroup_release, 0,
+ GFP_KERNEL);
+ if (ret) {
+ kfree(objcg);
+ return NULL;
+ }
+ INIT_LIST_HEAD(&objcg->list);
+ return objcg;
+}
+
+static void memcg_reparent_objcgs(struct mem_cgroup *memcg,
+ struct mem_cgroup *parent)
+{
+ struct obj_cgroup *objcg, *iter;
+
+ objcg = rcu_replace_pointer(memcg->objcg, NULL, true);
+
+ spin_lock_irq(&objcg_lock);
+
+ /* 1) Ready to reparent active objcg. */
+ list_add(&objcg->list, &memcg->objcg_list);
+ /* 2) Reparent active objcg and already reparented objcgs to parent. */
+ list_for_each_entry(iter, &memcg->objcg_list, list)
+ WRITE_ONCE(iter->memcg, parent);
+ /* 3) Move already reparented objcgs to the parent's list */
+ list_splice(&memcg->objcg_list, &parent->objcg_list);
+
+ spin_unlock_irq(&objcg_lock);
+
+ percpu_ref_kill(&objcg->refcnt);
+}
+
+/*
+ * A lot of the calls to the cache allocation functions are expected to be
+ * inlined by the compiler. Since the calls to memcg_slab_pre_alloc_hook() are
+ * conditional to this static branch, we'll have to allow modules that does
+ * kmem_cache_alloc and the such to see this symbol as well
+ */
+DEFINE_STATIC_KEY_FALSE(memcg_kmem_online_key);
+EXPORT_SYMBOL(memcg_kmem_online_key);
+
+DEFINE_STATIC_KEY_FALSE(memcg_bpf_enabled_key);
+EXPORT_SYMBOL(memcg_bpf_enabled_key);
+#endif
+
+/**
+ * mem_cgroup_css_from_folio - css of the memcg associated with a folio
+ * @folio: folio of interest
+ *
+ * If memcg is bound to the default hierarchy, css of the memcg associated
+ * with @folio is returned. The returned css remains associated with @folio
+ * until it is released.
+ *
+ * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
+ * is returned.
+ */
+struct cgroup_subsys_state *mem_cgroup_css_from_folio(struct folio *folio)
+{
+ struct mem_cgroup *memcg = folio_memcg(folio);
+
+ 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();
+ /* page_folio() is racy here, but the entire function is racy anyway */
+ memcg = folio_memcg_check(page_folio(page));
+
+ while (memcg && !(memcg->css.flags & CSS_ONLINE))
+ memcg = parent_mem_cgroup(memcg);
+ if (memcg)
+ ino = cgroup_ino(memcg->css.cgroup);
+ rcu_read_unlock();
+ return ino;
+}
+
+static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz,
+ struct mem_cgroup_tree_per_node *mctz,
+ unsigned long new_usage_in_excess)
+{
+ struct rb_node **p = &mctz->rb_root.rb_node;
+ struct rb_node *parent = NULL;
+ struct mem_cgroup_per_node *mz_node;
+ bool rightmost = true;
+
+ if (mz->on_tree)
+ return;
+
+ mz->usage_in_excess = new_usage_in_excess;
+ if (!mz->usage_in_excess)
+ return;
+ while (*p) {
+ parent = *p;
+ mz_node = rb_entry(parent, struct mem_cgroup_per_node,
+ tree_node);
+ if (mz->usage_in_excess < mz_node->usage_in_excess) {
+ p = &(*p)->rb_left;
+ rightmost = false;
+ } else {
+ p = &(*p)->rb_right;
+ }
+ }
+
+ if (rightmost)
+ mctz->rb_rightmost = &mz->tree_node;
+
+ rb_link_node(&mz->tree_node, parent, p);
+ rb_insert_color(&mz->tree_node, &mctz->rb_root);
+ mz->on_tree = true;
+}
+
+static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
+ struct mem_cgroup_tree_per_node *mctz)
+{
+ if (!mz->on_tree)
+ return;
+
+ if (&mz->tree_node == mctz->rb_rightmost)
+ mctz->rb_rightmost = rb_prev(&mz->tree_node);
+
+ rb_erase(&mz->tree_node, &mctz->rb_root);
+ mz->on_tree = false;
+}
+
+static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
+ struct mem_cgroup_tree_per_node *mctz)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&mctz->lock, flags);
+ __mem_cgroup_remove_exceeded(mz, mctz);
+ spin_unlock_irqrestore(&mctz->lock, flags);
+}
+
+static unsigned long soft_limit_excess(struct mem_cgroup *memcg)
+{
+ unsigned long nr_pages = page_counter_read(&memcg->memory);
+ unsigned long soft_limit = READ_ONCE(memcg->soft_limit);
+ unsigned long excess = 0;
+
+ if (nr_pages > soft_limit)
+ excess = nr_pages - soft_limit;
+
+ return excess;
+}
+
+static void mem_cgroup_update_tree(struct mem_cgroup *memcg, int nid)
+{
+ unsigned long excess;
+ struct mem_cgroup_per_node *mz;
+ struct mem_cgroup_tree_per_node *mctz;
+
+ if (lru_gen_enabled()) {
+ if (soft_limit_excess(memcg))
+ lru_gen_soft_reclaim(memcg, nid);
+ return;
+ }
+
+ mctz = soft_limit_tree.rb_tree_per_node[nid];
+ 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 = memcg->nodeinfo[nid];
+ 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 = memcg->nodeinfo[nid];
+ mctz = soft_limit_tree.rb_tree_per_node[nid];
+ if (mctz)
+ mem_cgroup_remove_exceeded(mz, mctz);
+ }
+}
+
+static struct mem_cgroup_per_node *
+__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
+{
+ struct mem_cgroup_per_node *mz;
+
+retry:
+ mz = NULL;
+ if (!mctz->rb_rightmost)
+ goto done; /* Nothing to reclaim from */
+
+ mz = rb_entry(mctz->rb_rightmost,
+ struct mem_cgroup_per_node, tree_node);
+ /*
+ * Remove the node now but someone else can add it back,
+ * we will to add it back at the end of reclaim to its correct
+ * position in the tree.
+ */
+ __mem_cgroup_remove_exceeded(mz, mctz);
+ if (!soft_limit_excess(mz->memcg) ||
+ !css_tryget(&mz->memcg->css))
+ goto retry;
+done:
+ return mz;
+}
+
+static struct mem_cgroup_per_node *
+mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
+{
+ struct mem_cgroup_per_node *mz;
+
+ spin_lock_irq(&mctz->lock);
+ mz = __mem_cgroup_largest_soft_limit_node(mctz);
+ spin_unlock_irq(&mctz->lock);
+ return mz;
+}
+
+/*
+ * memcg and lruvec stats flushing
+ *
+ * Many codepaths leading to stats update or read are performance sensitive and
+ * adding stats flushing in such codepaths is not desirable. So, to optimize the
+ * flushing the kernel does:
+ *
+ * 1) Periodically and asynchronously flush the stats every 2 seconds to not let
+ * rstat update tree grow unbounded.
+ *
+ * 2) Flush the stats synchronously on reader side only when there are more than
+ * (MEMCG_CHARGE_BATCH * nr_cpus) update events. Though this optimization
+ * will let stats be out of sync by atmost (MEMCG_CHARGE_BATCH * nr_cpus) but
+ * only for 2 seconds due to (1).
+ */
+static void flush_memcg_stats_dwork(struct work_struct *w);
+static DECLARE_DEFERRABLE_WORK(stats_flush_dwork, flush_memcg_stats_dwork);
+static DEFINE_PER_CPU(unsigned int, stats_updates);
+static atomic_t stats_flush_ongoing = ATOMIC_INIT(0);
+static atomic_t stats_flush_threshold = ATOMIC_INIT(0);
+static u64 flush_next_time;
+
+#define FLUSH_TIME (2UL*HZ)
+
+/*
+ * Accessors to ensure that preemption is disabled on PREEMPT_RT because it can
+ * not rely on this as part of an acquired spinlock_t lock. These functions are
+ * never used in hardirq context on PREEMPT_RT and therefore disabling preemtion
+ * is sufficient.
+ */
+static void memcg_stats_lock(void)
+{
+ preempt_disable_nested();
+ VM_WARN_ON_IRQS_ENABLED();
+}
+
+static void __memcg_stats_lock(void)
+{
+ preempt_disable_nested();
+}
+
+static void memcg_stats_unlock(void)
+{
+ preempt_enable_nested();
+}
+
+static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val)
+{
+ unsigned int x;
+
+ if (!val)
+ return;
+
+ cgroup_rstat_updated(memcg->css.cgroup, smp_processor_id());
+
+ x = __this_cpu_add_return(stats_updates, abs(val));
+ if (x > MEMCG_CHARGE_BATCH) {
+ /*
+ * If stats_flush_threshold exceeds the threshold
+ * (>num_online_cpus()), cgroup stats update will be triggered
+ * in __mem_cgroup_flush_stats(). Increasing this var further
+ * is redundant and simply adds overhead in atomic update.
+ */
+ if (atomic_read(&stats_flush_threshold) <= num_online_cpus())
+ atomic_add(x / MEMCG_CHARGE_BATCH, &stats_flush_threshold);
+ __this_cpu_write(stats_updates, 0);
+ }
+}
+
+static void do_flush_stats(void)
+{
+ /*
+ * We always flush the entire tree, so concurrent flushers can just
+ * skip. This avoids a thundering herd problem on the rstat global lock
+ * from memcg flushers (e.g. reclaim, refault, etc).
+ */
+ if (atomic_read(&stats_flush_ongoing) ||
+ atomic_xchg(&stats_flush_ongoing, 1))
+ return;
+
+ WRITE_ONCE(flush_next_time, jiffies_64 + 2*FLUSH_TIME);
+
+ cgroup_rstat_flush(root_mem_cgroup->css.cgroup);
+
+ atomic_set(&stats_flush_threshold, 0);
+ atomic_set(&stats_flush_ongoing, 0);
+}
+
+void mem_cgroup_flush_stats(void)
+{
+ if (atomic_read(&stats_flush_threshold) > num_online_cpus())
+ do_flush_stats();
+}
+
+void mem_cgroup_flush_stats_ratelimited(void)
+{
+ if (time_after64(jiffies_64, READ_ONCE(flush_next_time)))
+ mem_cgroup_flush_stats();
+}
+
+static void flush_memcg_stats_dwork(struct work_struct *w)
+{
+ /*
+ * Always flush here so that flushing in latency-sensitive paths is
+ * as cheap as possible.
+ */
+ do_flush_stats();
+ queue_delayed_work(system_unbound_wq, &stats_flush_dwork, FLUSH_TIME);
+}
+
+/* Subset of vm_event_item to report for memcg event stats */
+static const unsigned int memcg_vm_event_stat[] = {
+ PGPGIN,
+ PGPGOUT,
+ PGSCAN_KSWAPD,
+ PGSCAN_DIRECT,
+ PGSCAN_KHUGEPAGED,
+ PGSTEAL_KSWAPD,
+ PGSTEAL_DIRECT,
+ PGSTEAL_KHUGEPAGED,
+ PGFAULT,
+ PGMAJFAULT,
+ PGREFILL,
+ PGACTIVATE,
+ PGDEACTIVATE,
+ PGLAZYFREE,
+ PGLAZYFREED,
+#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
+ ZSWPIN,
+ ZSWPOUT,
+#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ THP_FAULT_ALLOC,
+ THP_COLLAPSE_ALLOC,
+#endif
+};
+
+#define NR_MEMCG_EVENTS ARRAY_SIZE(memcg_vm_event_stat)
+static int mem_cgroup_events_index[NR_VM_EVENT_ITEMS] __read_mostly;
+
+static void init_memcg_events(void)
+{
+ int i;
+
+ for (i = 0; i < NR_MEMCG_EVENTS; ++i)
+ mem_cgroup_events_index[memcg_vm_event_stat[i]] = i + 1;
+}
+
+static inline int memcg_events_index(enum vm_event_item idx)
+{
+ return mem_cgroup_events_index[idx] - 1;
+}
+
+struct memcg_vmstats_percpu {
+ /* Local (CPU and cgroup) page state & events */
+ long state[MEMCG_NR_STAT];
+ unsigned long events[NR_MEMCG_EVENTS];
+
+ /* Delta calculation for lockless upward propagation */
+ long state_prev[MEMCG_NR_STAT];
+ unsigned long events_prev[NR_MEMCG_EVENTS];
+
+ /* Cgroup1: threshold notifications & softlimit tree updates */
+ unsigned long nr_page_events;
+ unsigned long targets[MEM_CGROUP_NTARGETS];
+};
+
+struct memcg_vmstats {
+ /* Aggregated (CPU and subtree) page state & events */
+ long state[MEMCG_NR_STAT];
+ unsigned long events[NR_MEMCG_EVENTS];
+
+ /* Non-hierarchical (CPU aggregated) page state & events */
+ long state_local[MEMCG_NR_STAT];
+ unsigned long events_local[NR_MEMCG_EVENTS];
+
+ /* Pending child counts during tree propagation */
+ long state_pending[MEMCG_NR_STAT];
+ unsigned long events_pending[NR_MEMCG_EVENTS];
+};
+
+unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
+{
+ long x = READ_ONCE(memcg->vmstats->state[idx]);
+#ifdef CONFIG_SMP
+ if (x < 0)
+ x = 0;
+#endif
+ return x;
+}
+
+/**
+ * __mod_memcg_state - update cgroup memory statistics
+ * @memcg: the memory cgroup
+ * @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item
+ * @val: delta to add to the counter, can be negative
+ */
+void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val)
+{
+ if (mem_cgroup_disabled())
+ return;
+
+ __this_cpu_add(memcg->vmstats_percpu->state[idx], val);
+ memcg_rstat_updated(memcg, val);
+}
+
+/* idx can be of type enum memcg_stat_item or node_stat_item. */
+static unsigned long memcg_page_state_local(struct mem_cgroup *memcg, int idx)
+{
+ long x = READ_ONCE(memcg->vmstats->state_local[idx]);
+
+#ifdef CONFIG_SMP
+ if (x < 0)
+ x = 0;
+#endif
+ return x;
+}
+
+void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
+ int val)
+{
+ struct mem_cgroup_per_node *pn;
+ struct mem_cgroup *memcg;
+
+ pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
+ memcg = pn->memcg;
+
+ /*
+ * The caller from rmap relay on disabled preemption becase they never
+ * update their counter from in-interrupt context. For these two
+ * counters we check that the update is never performed from an
+ * interrupt context while other caller need to have disabled interrupt.
+ */
+ __memcg_stats_lock();
+ if (IS_ENABLED(CONFIG_DEBUG_VM)) {
+ switch (idx) {
+ case NR_ANON_MAPPED:
+ case NR_FILE_MAPPED:
+ case NR_ANON_THPS:
+ case NR_SHMEM_PMDMAPPED:
+ case NR_FILE_PMDMAPPED:
+ WARN_ON_ONCE(!in_task());
+ break;
+ default:
+ VM_WARN_ON_IRQS_ENABLED();
+ }
+ }
+
+ /* Update memcg */
+ __this_cpu_add(memcg->vmstats_percpu->state[idx], val);
+
+ /* Update lruvec */
+ __this_cpu_add(pn->lruvec_stats_percpu->state[idx], val);
+
+ memcg_rstat_updated(memcg, val);
+ memcg_stats_unlock();
+}
+
+/**
+ * __mod_lruvec_state - update lruvec memory statistics
+ * @lruvec: the lruvec
+ * @idx: the stat item
+ * @val: delta to add to the counter, can be negative
+ *
+ * The lruvec is the intersection of the NUMA node and a cgroup. This
+ * function updates the all three counters that are affected by a
+ * change of state at this level: per-node, per-cgroup, per-lruvec.
+ */
+void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
+ int val)
+{
+ /* Update node */
+ __mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
+
+ /* Update memcg and lruvec */
+ if (!mem_cgroup_disabled())
+ __mod_memcg_lruvec_state(lruvec, idx, val);
+}
+
+void __mod_lruvec_page_state(struct page *page, enum node_stat_item idx,
+ int val)
+{
+ struct page *head = compound_head(page); /* rmap on tail pages */
+ struct mem_cgroup *memcg;
+ pg_data_t *pgdat = page_pgdat(page);
+ struct lruvec *lruvec;
+
+ rcu_read_lock();
+ memcg = page_memcg(head);
+ /* Untracked pages have no memcg, no lruvec. Update only the node */
+ if (!memcg) {
+ rcu_read_unlock();
+ __mod_node_page_state(pgdat, idx, val);
+ return;
+ }
+
+ lruvec = mem_cgroup_lruvec(memcg, pgdat);
+ __mod_lruvec_state(lruvec, idx, val);
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL(__mod_lruvec_page_state);
+
+void __mod_lruvec_kmem_state(void *p, enum node_stat_item idx, int val)
+{
+ pg_data_t *pgdat = page_pgdat(virt_to_page(p));
+ struct mem_cgroup *memcg;
+ struct lruvec *lruvec;
+
+ rcu_read_lock();
+ memcg = mem_cgroup_from_slab_obj(p);
+
+ /*
+ * Untracked pages have no memcg, no lruvec. Update only the
+ * node. If we reparent the slab objects to the root memcg,
+ * when we free the slab object, we need to update the per-memcg
+ * vmstats to keep it correct for the root memcg.
+ */
+ if (!memcg) {
+ __mod_node_page_state(pgdat, idx, val);
+ } else {
+ lruvec = mem_cgroup_lruvec(memcg, pgdat);
+ __mod_lruvec_state(lruvec, idx, val);
+ }
+ rcu_read_unlock();
+}
+
+/**
+ * __count_memcg_events - account VM events in a cgroup
+ * @memcg: the memory cgroup
+ * @idx: the event item
+ * @count: the number of events that occurred
+ */
+void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx,
+ unsigned long count)
+{
+ int index = memcg_events_index(idx);
+
+ if (mem_cgroup_disabled() || index < 0)
+ return;
+
+ memcg_stats_lock();
+ __this_cpu_add(memcg->vmstats_percpu->events[index], count);
+ memcg_rstat_updated(memcg, count);
+ memcg_stats_unlock();
+}
+
+static unsigned long memcg_events(struct mem_cgroup *memcg, int event)
+{
+ int index = memcg_events_index(event);
+
+ if (index < 0)
+ return 0;
+ return READ_ONCE(memcg->vmstats->events[index]);
+}
+
+static unsigned long memcg_events_local(struct mem_cgroup *memcg, int event)
+{
+ int index = memcg_events_index(event);
+
+ if (index < 0)
+ return 0;
+
+ return READ_ONCE(memcg->vmstats->events_local[index]);
+}
+
+static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
+ int nr_pages)
+{
+ /* pagein of a big page is an event. So, ignore page size */
+ if (nr_pages > 0)
+ __count_memcg_events(memcg, PGPGIN, 1);
+ else {
+ __count_memcg_events(memcg, PGPGOUT, 1);
+ nr_pages = -nr_pages; /* for event */
+ }
+
+ __this_cpu_add(memcg->vmstats_percpu->nr_page_events, nr_pages);
+}
+
+static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
+ enum mem_cgroup_events_target target)
+{
+ unsigned long val, next;
+
+ val = __this_cpu_read(memcg->vmstats_percpu->nr_page_events);
+ next = __this_cpu_read(memcg->vmstats_percpu->targets[target]);
+ /* from time_after() in jiffies.h */
+ if ((long)(next - val) < 0) {
+ switch (target) {
+ case MEM_CGROUP_TARGET_THRESH:
+ next = val + THRESHOLDS_EVENTS_TARGET;
+ break;
+ case MEM_CGROUP_TARGET_SOFTLIMIT:
+ next = val + SOFTLIMIT_EVENTS_TARGET;
+ break;
+ default:
+ break;
+ }
+ __this_cpu_write(memcg->vmstats_percpu->targets[target], next);
+ return true;
+ }
+ return false;
+}
+
+/*
+ * Check events in order.
+ *
+ */
+static void memcg_check_events(struct mem_cgroup *memcg, int nid)
+{
+ if (IS_ENABLED(CONFIG_PREEMPT_RT))
+ return;
+
+ /* threshold event is triggered in finer grain than soft limit */
+ if (unlikely(mem_cgroup_event_ratelimit(memcg,
+ MEM_CGROUP_TARGET_THRESH))) {
+ bool do_softlimit;
+
+ do_softlimit = mem_cgroup_event_ratelimit(memcg,
+ MEM_CGROUP_TARGET_SOFTLIMIT);
+ mem_cgroup_threshold(memcg);
+ if (unlikely(do_softlimit))
+ mem_cgroup_update_tree(memcg, nid);
+ }
+}
+
+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);
+
+static __always_inline struct mem_cgroup *active_memcg(void)
+{
+ if (!in_task())
+ return this_cpu_read(int_active_memcg);
+ else
+ return current->active_memcg;
+}
+
+/**
+ * get_mem_cgroup_from_mm: Obtain a reference on given mm_struct's memcg.
+ * @mm: mm from which memcg should be extracted. It can be NULL.
+ *
+ * Obtain a reference on mm->memcg and returns it if successful. If mm
+ * is NULL, then the memcg is chosen as follows:
+ * 1) The active memcg, if set.
+ * 2) current->mm->memcg, if available
+ * 3) root memcg
+ * If mem_cgroup is disabled, NULL is returned.
+ */
+struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
+{
+ struct mem_cgroup *memcg;
+
+ if (mem_cgroup_disabled())
+ return NULL;
+
+ /*
+ * Page cache insertions can happen without an
+ * actual mm context, e.g. during disk probing
+ * on boot, loopback IO, acct() writes etc.
+ *
+ * No need to css_get on root memcg as the reference
+ * counting is disabled on the root level in the
+ * cgroup core. See CSS_NO_REF.
+ */
+ if (unlikely(!mm)) {
+ memcg = active_memcg();
+ if (unlikely(memcg)) {
+ /* remote memcg must hold a ref */
+ css_get(&memcg->css);
+ return memcg;
+ }
+ mm = current->mm;
+ if (unlikely(!mm))
+ return root_mem_cgroup;
+ }
+
+ rcu_read_lock();
+ do {
+ memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
+ if (unlikely(!memcg))
+ memcg = root_mem_cgroup;
+ } while (!css_tryget(&memcg->css));
+ rcu_read_unlock();
+ return memcg;
+}
+EXPORT_SYMBOL(get_mem_cgroup_from_mm);
+
+static __always_inline bool memcg_kmem_bypass(void)
+{
+ /* Allow remote memcg charging from any context. */
+ if (unlikely(active_memcg()))
+ return false;
+
+ /* Memcg to charge can't be determined. */
+ if (!in_task() || !current->mm || (current->flags & PF_KTHREAD))
+ return true;
+
+ return false;
+}
+
+/**
+ * mem_cgroup_iter - iterate over memory cgroup hierarchy
+ * @root: hierarchy root
+ * @prev: previously returned memcg, NULL on first invocation
+ * @reclaim: cookie for shared reclaim walks, NULL for full walks
+ *
+ * Returns references to children of the hierarchy below @root, or
+ * @root itself, or %NULL after a full round-trip.
+ *
+ * Caller must pass the return value in @prev on subsequent
+ * invocations for reference counting, or use mem_cgroup_iter_break()
+ * to cancel a hierarchy walk before the round-trip is complete.
+ *
+ * Reclaimers can specify a node in @reclaim to divide up the memcgs
+ * in the hierarchy among all concurrent reclaimers operating on the
+ * same node.
+ */
+struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
+ struct mem_cgroup *prev,
+ struct mem_cgroup_reclaim_cookie *reclaim)
+{
+ struct mem_cgroup_reclaim_iter *iter;
+ struct cgroup_subsys_state *css = NULL;
+ struct mem_cgroup *memcg = NULL;
+ struct mem_cgroup *pos = NULL;
+
+ if (mem_cgroup_disabled())
+ return NULL;
+
+ if (!root)
+ root = root_mem_cgroup;
+
+ rcu_read_lock();
+
+ if (reclaim) {
+ struct mem_cgroup_per_node *mz;
+
+ mz = root->nodeinfo[reclaim->pgdat->node_id];
+ iter = &mz->iter;
+
+ /*
+ * On start, join the current reclaim iteration cycle.
+ * Exit when a concurrent walker completes it.
+ */
+ if (!prev)
+ reclaim->generation = iter->generation;
+ else if (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);
+ }
+ } else if (prev) {
+ pos = prev;
+ }
+
+ 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.
+ */
+ if (css == &root->css || css_tryget(css)) {
+ memcg = mem_cgroup_from_css(css);
+ break;
+ }
+ }
+
+ 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++;
+ }
+
+out_unlock:
+ rcu_read_unlock();
+ if (prev && prev != root)
+ css_put(&prev->css);
+
+ return memcg;
+}
+
+/**
+ * mem_cgroup_iter_break - abort a hierarchy walk prematurely
+ * @root: hierarchy root
+ * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
+ */
+void mem_cgroup_iter_break(struct mem_cgroup *root,
+ struct mem_cgroup *prev)
+{
+ if (!root)
+ root = root_mem_cgroup;
+ if (prev && prev != root)
+ css_put(&prev->css);
+}
+
+static void __invalidate_reclaim_iterators(struct mem_cgroup *from,
+ struct mem_cgroup *dead_memcg)
+{
+ struct mem_cgroup_reclaim_iter *iter;
+ struct mem_cgroup_per_node *mz;
+ int nid;
+
+ for_each_node(nid) {
+ mz = from->nodeinfo[nid];
+ iter = &mz->iter;
+ cmpxchg(&iter->position, dead_memcg, NULL);
+ }
+}
+
+static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
+{
+ struct mem_cgroup *memcg = dead_memcg;
+ struct mem_cgroup *last;
+
+ do {
+ __invalidate_reclaim_iterators(memcg, dead_memcg);
+ last = memcg;
+ } while ((memcg = parent_mem_cgroup(memcg)));
+
+ /*
+ * When cgroup1 non-hierarchy mode is used,
+ * parent_mem_cgroup() does not walk all the way up to the
+ * cgroup root (root_mem_cgroup). So we have to handle
+ * dead_memcg from cgroup root separately.
+ */
+ if (!mem_cgroup_is_root(last))
+ __invalidate_reclaim_iterators(root_mem_cgroup,
+ dead_memcg);
+}
+
+/**
+ * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
+ * @memcg: hierarchy root
+ * @fn: function to call for each task
+ * @arg: argument passed to @fn
+ *
+ * This function iterates over tasks attached to @memcg or to any of its
+ * descendants and calls @fn for each task. If @fn returns a non-zero
+ * value, the function breaks the iteration loop. Otherwise, it will iterate
+ * over all tasks and return 0.
+ *
+ * This function must not be called for the root memory cgroup.
+ */
+void 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(mem_cgroup_is_root(memcg));
+
+ for_each_mem_cgroup_tree(iter, memcg) {
+ struct css_task_iter it;
+ struct task_struct *task;
+
+ css_task_iter_start(&iter->css, CSS_TASK_ITER_PROCS, &it);
+ while (!ret && (task = css_task_iter_next(&it)))
+ ret = fn(task, arg);
+ css_task_iter_end(&it);
+ if (ret) {
+ mem_cgroup_iter_break(memcg, iter);
+ break;
+ }
+ }
+}
+
+#ifdef CONFIG_DEBUG_VM
+void lruvec_memcg_debug(struct lruvec *lruvec, struct folio *folio)
+{
+ struct mem_cgroup *memcg;
+
+ if (mem_cgroup_disabled())
+ return;
+
+ memcg = folio_memcg(folio);
+
+ if (!memcg)
+ VM_BUG_ON_FOLIO(!mem_cgroup_is_root(lruvec_memcg(lruvec)), folio);
+ else
+ VM_BUG_ON_FOLIO(lruvec_memcg(lruvec) != memcg, folio);
+}
+#endif
+
+/**
+ * folio_lruvec_lock - Lock the lruvec for a folio.
+ * @folio: Pointer to the folio.
+ *
+ * These functions are safe to use under any of the following conditions:
+ * - folio locked
+ * - folio_test_lru false
+ * - folio_memcg_lock()
+ * - folio frozen (refcount of 0)
+ *
+ * Return: The lruvec this folio is on with its lock held.
+ */
+struct lruvec *folio_lruvec_lock(struct folio *folio)
+{
+ struct lruvec *lruvec = folio_lruvec(folio);
+
+ spin_lock(&lruvec->lru_lock);
+ lruvec_memcg_debug(lruvec, folio);
+
+ return lruvec;
+}
+
+/**
+ * folio_lruvec_lock_irq - Lock the lruvec for a folio.
+ * @folio: Pointer to the folio.
+ *
+ * These functions are safe to use under any of the following conditions:
+ * - folio locked
+ * - folio_test_lru false
+ * - folio_memcg_lock()
+ * - folio frozen (refcount of 0)
+ *
+ * Return: The lruvec this folio is on with its lock held and interrupts
+ * disabled.
+ */
+struct lruvec *folio_lruvec_lock_irq(struct folio *folio)
+{
+ struct lruvec *lruvec = folio_lruvec(folio);
+
+ spin_lock_irq(&lruvec->lru_lock);
+ lruvec_memcg_debug(lruvec, folio);
+
+ return lruvec;
+}
+
+/**
+ * folio_lruvec_lock_irqsave - Lock the lruvec for a folio.
+ * @folio: Pointer to the folio.
+ * @flags: Pointer to irqsave flags.
+ *
+ * These functions are safe to use under any of the following conditions:
+ * - folio locked
+ * - folio_test_lru false
+ * - folio_memcg_lock()
+ * - folio frozen (refcount of 0)
+ *
+ * Return: The lruvec this folio is on with its lock held and interrupts
+ * disabled.
+ */
+struct lruvec *folio_lruvec_lock_irqsave(struct folio *folio,
+ unsigned long *flags)
+{
+ struct lruvec *lruvec = folio_lruvec(folio);
+
+ spin_lock_irqsave(&lruvec->lru_lock, *flags);
+ lruvec_memcg_debug(lruvec, folio);
+
+ 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.
+ */
+void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
+ int zid, int nr_pages)
+{
+ struct mem_cgroup_per_node *mz;
+ unsigned long *lru_size;
+ long size;
+
+ if (mem_cgroup_disabled())
+ return;
+
+ mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
+ lru_size = &mz->lru_zone_size[zid][lru];
+
+ if (nr_pages < 0)
+ *lru_size += nr_pages;
+
+ size = *lru_size;
+ if (WARN_ONCE(size < 0,
+ "%s(%p, %d, %d): lru_size %ld\n",
+ __func__, lruvec, lru, nr_pages, size)) {
+ VM_BUG_ON(1);
+ *lru_size = 0;
+ }
+
+ if (nr_pages > 0)
+ *lru_size += nr_pages;
+}
+
+/**
+ * mem_cgroup_margin - calculate chargeable space of a memory cgroup
+ * @memcg: the memory cgroup
+ *
+ * Returns the maximum amount of memory @mem can be charged with, in
+ * pages.
+ */
+static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
+{
+ unsigned long margin = 0;
+ unsigned long count;
+ unsigned long limit;
+
+ count = page_counter_read(&memcg->memory);
+ limit = READ_ONCE(memcg->memory.max);
+ if (count < limit)
+ margin = limit - count;
+
+ if (do_memsw_account()) {
+ count = page_counter_read(&memcg->memsw);
+ limit = READ_ONCE(memcg->memsw.max);
+ if (count < limit)
+ margin = min(margin, limit - count);
+ else
+ margin = 0;
+ }
+
+ return margin;
+}
+
+/*
+ * A routine for checking "mem" is under move_account() or not.
+ *
+ * Checking a cgroup is mc.from or mc.to or under hierarchy of
+ * moving cgroups. This is for waiting at high-memory pressure
+ * caused by "move".
+ */
+static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
+{
+ struct mem_cgroup *from;
+ struct mem_cgroup *to;
+ bool ret = false;
+ /*
+ * Unlike task_move routines, we access mc.to, mc.from not under
+ * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
+ */
+ spin_lock(&mc.lock);
+ from = mc.from;
+ to = mc.to;
+ if (!from)
+ goto unlock;
+
+ ret = mem_cgroup_is_descendant(from, memcg) ||
+ mem_cgroup_is_descendant(to, memcg);
+unlock:
+ spin_unlock(&mc.lock);
+ return ret;
+}
+
+static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
+{
+ if (mc.moving_task && current != mc.moving_task) {
+ if (mem_cgroup_under_move(memcg)) {
+ DEFINE_WAIT(wait);
+ prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
+ /* moving charge context might have finished. */
+ if (mc.moving_task)
+ schedule();
+ finish_wait(&mc.waitq, &wait);
+ return true;
+ }
+ }
+ return false;
+}
+
+struct memory_stat {
+ const char *name;
+ unsigned int idx;
+};
+
+static const struct memory_stat memory_stats[] = {
+ { "anon", NR_ANON_MAPPED },
+ { "file", NR_FILE_PAGES },
+ { "kernel", MEMCG_KMEM },
+ { "kernel_stack", NR_KERNEL_STACK_KB },
+ { "pagetables", NR_PAGETABLE },
+ { "sec_pagetables", NR_SECONDARY_PAGETABLE },
+ { "percpu", MEMCG_PERCPU_B },
+ { "sock", MEMCG_SOCK },
+ { "vmalloc", MEMCG_VMALLOC },
+ { "shmem", NR_SHMEM },
+#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
+ { "zswap", MEMCG_ZSWAP_B },
+ { "zswapped", MEMCG_ZSWAPPED },
+#endif
+ { "file_mapped", NR_FILE_MAPPED },
+ { "file_dirty", NR_FILE_DIRTY },
+ { "file_writeback", NR_WRITEBACK },
+#ifdef CONFIG_SWAP
+ { "swapcached", NR_SWAPCACHE },
+#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ { "anon_thp", NR_ANON_THPS },
+ { "file_thp", NR_FILE_THPS },
+ { "shmem_thp", NR_SHMEM_THPS },
+#endif
+ { "inactive_anon", NR_INACTIVE_ANON },
+ { "active_anon", NR_ACTIVE_ANON },
+ { "inactive_file", NR_INACTIVE_FILE },
+ { "active_file", NR_ACTIVE_FILE },
+ { "unevictable", NR_UNEVICTABLE },
+ { "slab_reclaimable", NR_SLAB_RECLAIMABLE_B },
+ { "slab_unreclaimable", NR_SLAB_UNRECLAIMABLE_B },
+
+ /* The memory events */
+ { "workingset_refault_anon", WORKINGSET_REFAULT_ANON },
+ { "workingset_refault_file", WORKINGSET_REFAULT_FILE },
+ { "workingset_activate_anon", WORKINGSET_ACTIVATE_ANON },
+ { "workingset_activate_file", WORKINGSET_ACTIVATE_FILE },
+ { "workingset_restore_anon", WORKINGSET_RESTORE_ANON },
+ { "workingset_restore_file", WORKINGSET_RESTORE_FILE },
+ { "workingset_nodereclaim", WORKINGSET_NODERECLAIM },
+};
+
+/* Translate stat items to the correct unit for memory.stat output */
+static int memcg_page_state_unit(int item)
+{
+ switch (item) {
+ case MEMCG_PERCPU_B:
+ case MEMCG_ZSWAP_B:
+ case NR_SLAB_RECLAIMABLE_B:
+ case NR_SLAB_UNRECLAIMABLE_B:
+ case WORKINGSET_REFAULT_ANON:
+ case WORKINGSET_REFAULT_FILE:
+ case WORKINGSET_ACTIVATE_ANON:
+ case WORKINGSET_ACTIVATE_FILE:
+ case WORKINGSET_RESTORE_ANON:
+ case WORKINGSET_RESTORE_FILE:
+ case WORKINGSET_NODERECLAIM:
+ return 1;
+ case NR_KERNEL_STACK_KB:
+ return SZ_1K;
+ default:
+ return PAGE_SIZE;
+ }
+}
+
+static inline unsigned long memcg_page_state_output(struct mem_cgroup *memcg,
+ int item)
+{
+ return memcg_page_state(memcg, item) * memcg_page_state_unit(item);
+}
+
+static void memcg_stat_format(struct mem_cgroup *memcg, struct seq_buf *s)
+{
+ 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:
+ */
+ mem_cgroup_flush_stats();
+
+ for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
+ u64 size;
+
+ size = memcg_page_state_output(memcg, memory_stats[i].idx);
+ seq_buf_printf(s, "%s %llu\n", memory_stats[i].name, size);
+
+ if (unlikely(memory_stats[i].idx == NR_SLAB_UNRECLAIMABLE_B)) {
+ size += memcg_page_state_output(memcg,
+ NR_SLAB_RECLAIMABLE_B);
+ seq_buf_printf(s, "slab %llu\n", size);
+ }
+ }
+
+ /* Accumulated memory events */
+ seq_buf_printf(s, "pgscan %lu\n",
+ memcg_events(memcg, PGSCAN_KSWAPD) +
+ memcg_events(memcg, PGSCAN_DIRECT) +
+ memcg_events(memcg, PGSCAN_KHUGEPAGED));
+ seq_buf_printf(s, "pgsteal %lu\n",
+ memcg_events(memcg, PGSTEAL_KSWAPD) +
+ memcg_events(memcg, PGSTEAL_DIRECT) +
+ memcg_events(memcg, PGSTEAL_KHUGEPAGED));
+
+ for (i = 0; i < ARRAY_SIZE(memcg_vm_event_stat); i++) {
+ if (memcg_vm_event_stat[i] == PGPGIN ||
+ memcg_vm_event_stat[i] == PGPGOUT)
+ continue;
+
+ seq_buf_printf(s, "%s %lu\n",
+ vm_event_name(memcg_vm_event_stat[i]),
+ memcg_events(memcg, memcg_vm_event_stat[i]));
+ }
+
+ /* The above should easily fit into one page */
+ WARN_ON_ONCE(seq_buf_has_overflowed(s));
+}
+
+static void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s);
+
+static void memory_stat_format(struct mem_cgroup *memcg, struct seq_buf *s)
+{
+ if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
+ memcg_stat_format(memcg, s);
+ else
+ memcg1_stat_format(memcg, s);
+ WARN_ON_ONCE(seq_buf_has_overflowed(s));
+}
+
+/**
+ * mem_cgroup_print_oom_context: Print OOM information relevant to
+ * memory controller.
+ * @memcg: The memory cgroup that went over limit
+ * @p: Task that is going to be killed
+ *
+ * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
+ * enabled
+ */
+void mem_cgroup_print_oom_context(struct mem_cgroup *memcg, struct task_struct *p)
+{
+ rcu_read_lock();
+
+ if (memcg) {
+ pr_cont(",oom_memcg=");
+ pr_cont_cgroup_path(memcg->css.cgroup);
+ } else
+ pr_cont(",global_oom");
+ if (p) {
+ pr_cont(",task_memcg=");
+ pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
+ }
+ rcu_read_unlock();
+}
+
+/**
+ * mem_cgroup_print_oom_meminfo: Print OOM memory information relevant to
+ * memory controller.
+ * @memcg: The memory cgroup that went over limit
+ */
+void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
+{
+ /* Use static buffer, for the caller is holding oom_lock. */
+ static char buf[PAGE_SIZE];
+ struct seq_buf s;
+
+ lockdep_assert_held(&oom_lock);
+
+ pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
+ K((u64)page_counter_read(&memcg->memory)),
+ K((u64)READ_ONCE(memcg->memory.max)), memcg->memory.failcnt);
+ if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
+ pr_info("swap: usage %llukB, limit %llukB, failcnt %lu\n",
+ K((u64)page_counter_read(&memcg->swap)),
+ K((u64)READ_ONCE(memcg->swap.max)), memcg->swap.failcnt);
+ else {
+ pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
+ K((u64)page_counter_read(&memcg->memsw)),
+ K((u64)memcg->memsw.max), memcg->memsw.failcnt);
+ pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
+ K((u64)page_counter_read(&memcg->kmem)),
+ K((u64)memcg->kmem.max), memcg->kmem.failcnt);
+ }
+
+ pr_info("Memory cgroup stats for ");
+ pr_cont_cgroup_path(memcg->css.cgroup);
+ pr_cont(":");
+ seq_buf_init(&s, buf, sizeof(buf));
+ memory_stat_format(memcg, &s);
+ seq_buf_do_printk(&s, KERN_INFO);
+}
+
+/*
+ * Return the memory (and swap, if configured) limit for a memcg.
+ */
+unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg)
+{
+ unsigned long max = READ_ONCE(memcg->memory.max);
+
+ if (do_memsw_account()) {
+ if (mem_cgroup_swappiness(memcg)) {
+ /* Calculate swap excess capacity from memsw limit */
+ unsigned long swap = READ_ONCE(memcg->memsw.max) - max;
+
+ max += min(swap, (unsigned long)total_swap_pages);
+ }
+ } else {
+ if (mem_cgroup_swappiness(memcg))
+ max += min(READ_ONCE(memcg->swap.max),
+ (unsigned long)total_swap_pages);
+ }
+ return max;
+}
+
+unsigned long mem_cgroup_size(struct mem_cgroup *memcg)
+{
+ return page_counter_read(&memcg->memory);
+}
+
+static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
+ int order)
+{
+ struct oom_control oc = {
+ .zonelist = NULL,
+ .nodemask = NULL,
+ .memcg = memcg,
+ .gfp_mask = gfp_mask,
+ .order = order,
+ };
+ bool ret = true;
+
+ if (mutex_lock_killable(&oom_lock))
+ return true;
+
+ if (mem_cgroup_margin(memcg) >= (1 << order))
+ goto unlock;
+
+ /*
+ * A few threads which were not waiting at mutex_lock_killable() can
+ * fail to bail out. Therefore, check again after holding oom_lock.
+ */
+ ret = task_is_dying() || out_of_memory(&oc);
+
+unlock:
+ mutex_unlock(&oom_lock);
+ return ret;
+}
+
+static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
+ pg_data_t *pgdat,
+ gfp_t gfp_mask,
+ unsigned long *total_scanned)
+{
+ struct mem_cgroup *victim = NULL;
+ int total = 0;
+ int loop = 0;
+ unsigned long excess;
+ unsigned long nr_scanned;
+ struct mem_cgroup_reclaim_cookie reclaim = {
+ .pgdat = pgdat,
+ };
+
+ excess = soft_limit_excess(root_memcg);
+
+ while (1) {
+ victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
+ if (!victim) {
+ loop++;
+ if (loop >= 2) {
+ /*
+ * If we have not been able to reclaim
+ * anything, it might because there are
+ * no reclaimable pages under this hierarchy
+ */
+ if (!total)
+ break;
+ /*
+ * We want to do more targeted reclaim.
+ * excess >> 2 is not to excessive so as to
+ * reclaim too much, nor too less that we keep
+ * coming back to reclaim from this cgroup
+ */
+ if (total >= (excess >> 2) ||
+ (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
+ break;
+ }
+ continue;
+ }
+ total += mem_cgroup_shrink_node(victim, gfp_mask, false,
+ pgdat, &nr_scanned);
+ *total_scanned += nr_scanned;
+ if (!soft_limit_excess(root_memcg))
+ break;
+ }
+ mem_cgroup_iter_break(root_memcg, victim);
+ return total;
+}
+
+#ifdef CONFIG_LOCKDEP
+static struct lockdep_map memcg_oom_lock_dep_map = {
+ .name = "memcg_oom_lock",
+};
+#endif
+
+static DEFINE_SPINLOCK(memcg_oom_lock);
+
+/*
+ * Check OOM-Killer is already running under our hierarchy.
+ * If someone is running, return false.
+ */
+static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg)
+{
+ struct mem_cgroup *iter, *failed = NULL;
+
+ spin_lock(&memcg_oom_lock);
+
+ for_each_mem_cgroup_tree(iter, memcg) {
+ if (iter->oom_lock) {
+ /*
+ * this subtree of our hierarchy is already locked
+ * so we cannot give a lock.
+ */
+ failed = iter;
+ mem_cgroup_iter_break(memcg, iter);
+ break;
+ } else
+ iter->oom_lock = true;
+ }
+
+ if (failed) {
+ /*
+ * OK, we failed to lock the whole subtree so we have
+ * to clean up what we set up to the failing subtree
+ */
+ for_each_mem_cgroup_tree(iter, memcg) {
+ if (iter == failed) {
+ mem_cgroup_iter_break(memcg, iter);
+ break;
+ }
+ iter->oom_lock = false;
+ }
+ } else
+ mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_);
+
+ spin_unlock(&memcg_oom_lock);
+
+ return !failed;
+}
+
+static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
+{
+ struct mem_cgroup *iter;
+
+ spin_lock(&memcg_oom_lock);
+ mutex_release(&memcg_oom_lock_dep_map, _RET_IP_);
+ for_each_mem_cgroup_tree(iter, memcg)
+ iter->oom_lock = false;
+ spin_unlock(&memcg_oom_lock);
+}
+
+static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
+{
+ struct mem_cgroup *iter;
+
+ spin_lock(&memcg_oom_lock);
+ for_each_mem_cgroup_tree(iter, memcg)
+ iter->under_oom++;
+ spin_unlock(&memcg_oom_lock);
+}
+
+static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
+{
+ struct mem_cgroup *iter;
+
+ /*
+ * Be careful about under_oom underflows because a child memcg
+ * could have been added after mem_cgroup_mark_under_oom.
+ */
+ spin_lock(&memcg_oom_lock);
+ for_each_mem_cgroup_tree(iter, memcg)
+ if (iter->under_oom > 0)
+ iter->under_oom--;
+ spin_unlock(&memcg_oom_lock);
+}
+
+static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
+
+struct oom_wait_info {
+ struct mem_cgroup *memcg;
+ wait_queue_entry_t wait;
+};
+
+static int memcg_oom_wake_function(wait_queue_entry_t *wait,
+ unsigned mode, int sync, void *arg)
+{
+ struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
+ struct mem_cgroup *oom_wait_memcg;
+ struct oom_wait_info *oom_wait_info;
+
+ oom_wait_info = container_of(wait, struct oom_wait_info, wait);
+ oom_wait_memcg = oom_wait_info->memcg;
+
+ if (!mem_cgroup_is_descendant(wake_memcg, oom_wait_memcg) &&
+ !mem_cgroup_is_descendant(oom_wait_memcg, wake_memcg))
+ return 0;
+ return autoremove_wake_function(wait, mode, sync, arg);
+}
+
+static void memcg_oom_recover(struct mem_cgroup *memcg)
+{
+ /*
+ * For the following lockless ->under_oom test, the only required
+ * guarantee is that it must see the state asserted by an OOM when
+ * this function is called as a result of userland actions
+ * triggered by the notification of the OOM. This is trivially
+ * achieved by invoking mem_cgroup_mark_under_oom() before
+ * triggering notification.
+ */
+ if (memcg && memcg->under_oom)
+ __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
+}
+
+/*
+ * Returns true if successfully killed one or more processes. Though in some
+ * corner cases it can return true even without killing any process.
+ */
+static bool mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
+{
+ bool locked, ret;
+
+ if (order > PAGE_ALLOC_COSTLY_ORDER)
+ return false;
+
+ memcg_memory_event(memcg, MEMCG_OOM);
+
+ /*
+ * We are in the middle of the charge context here, so we
+ * don't want to block when potentially sitting on a callstack
+ * that holds all kinds of filesystem and mm locks.
+ *
+ * cgroup1 allows disabling the OOM killer and waiting for outside
+ * handling until the charge can succeed; remember the context and put
+ * the task to sleep at the end of the page fault when all locks are
+ * released.
+ *
+ * On the other hand, in-kernel OOM killer allows for an async victim
+ * memory reclaim (oom_reaper) and that means that we are not solely
+ * relying on the oom victim to make a forward progress and we can
+ * invoke the oom killer here.
+ *
+ * Please note that mem_cgroup_out_of_memory might fail to find a
+ * victim and then we have to bail out from the charge path.
+ */
+ if (READ_ONCE(memcg->oom_kill_disable)) {
+ if (current->in_user_fault) {
+ css_get(&memcg->css);
+ current->memcg_in_oom = memcg;
+ current->memcg_oom_gfp_mask = mask;
+ current->memcg_oom_order = order;
+ }
+ return false;
+ }
+
+ mem_cgroup_mark_under_oom(memcg);
+
+ locked = mem_cgroup_oom_trylock(memcg);
+
+ if (locked)
+ mem_cgroup_oom_notify(memcg);
+
+ mem_cgroup_unmark_under_oom(memcg);
+ ret = mem_cgroup_out_of_memory(memcg, mask, order);
+
+ if (locked)
+ mem_cgroup_oom_unlock(memcg);
+
+ return ret;
+}
+
+/**
+ * mem_cgroup_oom_synchronize - complete memcg OOM handling
+ * @handle: actually kill/wait or just clean up the OOM state
+ *
+ * This has to be called at the end of a page fault if the memcg OOM
+ * handler was enabled.
+ *
+ * Memcg supports userspace OOM handling where failed allocations must
+ * sleep on a waitqueue until the userspace task resolves the
+ * situation. Sleeping directly in the charge context with all kinds
+ * of locks held is not a good idea, instead we remember an OOM state
+ * in the task and mem_cgroup_oom_synchronize() has to be called at
+ * the end of the page fault to complete the OOM handling.
+ *
+ * Returns %true if an ongoing memcg OOM situation was detected and
+ * completed, %false otherwise.
+ */
+bool mem_cgroup_oom_synchronize(bool handle)
+{
+ struct mem_cgroup *memcg = current->memcg_in_oom;
+ struct oom_wait_info owait;
+ bool locked;
+
+ /* OOM is global, do not handle */
+ if (!memcg)
+ return false;
+
+ if (!handle)
+ goto cleanup;
+
+ owait.memcg = memcg;
+ owait.wait.flags = 0;
+ owait.wait.func = memcg_oom_wake_function;
+ owait.wait.private = current;
+ INIT_LIST_HEAD(&owait.wait.entry);
+
+ prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
+ mem_cgroup_mark_under_oom(memcg);
+
+ locked = mem_cgroup_oom_trylock(memcg);
+
+ if (locked)
+ mem_cgroup_oom_notify(memcg);
+
+ schedule();
+ mem_cgroup_unmark_under_oom(memcg);
+ finish_wait(&memcg_oom_waitq, &owait.wait);
+
+ if (locked)
+ mem_cgroup_oom_unlock(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 (mem_cgroup_is_root(memcg))
+ goto out;
+
+ /*
+ * If the victim task has been asynchronously moved to a different
+ * memory cgroup, we might end up killing tasks outside oom_domain.
+ * In this case it's better to ignore memory.group.oom.
+ */
+ if (unlikely(!mem_cgroup_is_descendant(memcg, oom_domain)))
+ goto out;
+
+ /*
+ * Traverse the memory cgroup hierarchy from the victim task's
+ * cgroup up to the OOMing cgroup (or root) to find the
+ * highest-level memory cgroup with oom.group set.
+ */
+ for (; memcg; memcg = parent_mem_cgroup(memcg)) {
+ if (READ_ONCE(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");
+}
+
+/**
+ * folio_memcg_lock - Bind a folio to its memcg.
+ * @folio: The folio.
+ *
+ * This function prevents unlocked LRU folios from being moved to
+ * another cgroup.
+ *
+ * It ensures lifetime of the bound memcg. The caller is responsible
+ * for the lifetime of the folio.
+ */
+void folio_memcg_lock(struct folio *folio)
+{
+ 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.
+ */
+ rcu_read_lock();
+
+ if (mem_cgroup_disabled())
+ return;
+again:
+ memcg = folio_memcg(folio);
+ if (unlikely(!memcg))
+ return;
+
+#ifdef CONFIG_PROVE_LOCKING
+ local_irq_save(flags);
+ might_lock(&memcg->move_lock);
+ local_irq_restore(flags);
+#endif
+
+ if (atomic_read(&memcg->moving_account) <= 0)
+ return;
+
+ spin_lock_irqsave(&memcg->move_lock, flags);
+ if (memcg != folio_memcg(folio)) {
+ spin_unlock_irqrestore(&memcg->move_lock, flags);
+ goto again;
+ }
+
+ /*
+ * When charge migration first begins, we can have multiple
+ * critical sections holding the fast-path RCU lock and one
+ * holding the slowpath move_lock. Track the task who has the
+ * move_lock for folio_memcg_unlock().
+ */
+ memcg->move_lock_task = current;
+ memcg->move_lock_flags = flags;
+}
+
+static void __folio_memcg_unlock(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();
+}
+
+/**
+ * folio_memcg_unlock - Release the binding between a folio and its memcg.
+ * @folio: The folio.
+ *
+ * This releases the binding created by folio_memcg_lock(). This does
+ * not change the accounting of this folio to its memcg, but it does
+ * permit others to change it.
+ */
+void folio_memcg_unlock(struct folio *folio)
+{
+ __folio_memcg_unlock(folio_memcg(folio));
+}
+
+struct memcg_stock_pcp {
+ local_lock_t stock_lock;
+ struct mem_cgroup *cached; /* this never be root cgroup */
+ unsigned int nr_pages;
+
+#ifdef CONFIG_MEMCG_KMEM
+ struct obj_cgroup *cached_objcg;
+ struct pglist_data *cached_pgdat;
+ unsigned int nr_bytes;
+ int nr_slab_reclaimable_b;
+ int nr_slab_unreclaimable_b;
+#endif
+
+ struct work_struct work;
+ unsigned long flags;
+#define FLUSHING_CACHED_CHARGE 0
+};
+static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock) = {
+ .stock_lock = INIT_LOCAL_LOCK(stock_lock),
+};
+static DEFINE_MUTEX(percpu_charge_mutex);
+
+#ifdef CONFIG_MEMCG_KMEM
+static struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock);
+static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
+ struct mem_cgroup *root_memcg);
+static void memcg_account_kmem(struct mem_cgroup *memcg, int nr_pages);
+
+#else
+static inline struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock)
+{
+ return NULL;
+}
+static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
+ struct mem_cgroup *root_memcg)
+{
+ return false;
+}
+static void memcg_account_kmem(struct mem_cgroup *memcg, int nr_pages)
+{
+}
+#endif
+
+/**
+ * consume_stock: Try to consume stocked charge on this cpu.
+ * @memcg: memcg to consume from.
+ * @nr_pages: how many pages to charge.
+ *
+ * The charges will only happen if @memcg matches the current cpu's memcg
+ * stock, and at least @nr_pages are available in that stock. Failure to
+ * service an allocation will refill the stock.
+ *
+ * returns true if successful, false otherwise.
+ */
+static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
+{
+ struct memcg_stock_pcp *stock;
+ unsigned long flags;
+ bool ret = false;
+
+ if (nr_pages > MEMCG_CHARGE_BATCH)
+ return ret;
+
+ local_lock_irqsave(&memcg_stock.stock_lock, flags);
+
+ stock = this_cpu_ptr(&memcg_stock);
+ if (memcg == READ_ONCE(stock->cached) && stock->nr_pages >= nr_pages) {
+ stock->nr_pages -= nr_pages;
+ ret = true;
+ }
+
+ local_unlock_irqrestore(&memcg_stock.stock_lock, 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 = READ_ONCE(stock->cached);
+
+ if (!old)
+ return;
+
+ if (stock->nr_pages) {
+ page_counter_uncharge(&old->memory, stock->nr_pages);
+ if (do_memsw_account())
+ page_counter_uncharge(&old->memsw, stock->nr_pages);
+ stock->nr_pages = 0;
+ }
+
+ css_put(&old->css);
+ WRITE_ONCE(stock->cached, NULL);
+}
+
+static void drain_local_stock(struct work_struct *dummy)
+{
+ struct memcg_stock_pcp *stock;
+ struct obj_cgroup *old = NULL;
+ unsigned long flags;
+
+ /*
+ * The only protection from cpu hotplug (memcg_hotplug_cpu_dead) vs.
+ * drain_stock races is that we always operate on local CPU stock
+ * here with IRQ disabled
+ */
+ local_lock_irqsave(&memcg_stock.stock_lock, flags);
+
+ stock = this_cpu_ptr(&memcg_stock);
+ old = drain_obj_stock(stock);
+ drain_stock(stock);
+ clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
+
+ local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
+ if (old)
+ obj_cgroup_put(old);
+}
+
+/*
+ * 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;
+
+ stock = this_cpu_ptr(&memcg_stock);
+ if (READ_ONCE(stock->cached) != memcg) { /* reset if necessary */
+ drain_stock(stock);
+ css_get(&memcg->css);
+ WRITE_ONCE(stock->cached, memcg);
+ }
+ stock->nr_pages += nr_pages;
+
+ if (stock->nr_pages > MEMCG_CHARGE_BATCH)
+ drain_stock(stock);
+}
+
+static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
+{
+ unsigned long flags;
+
+ local_lock_irqsave(&memcg_stock.stock_lock, flags);
+ __refill_stock(memcg, nr_pages);
+ local_unlock_irqrestore(&memcg_stock.stock_lock, 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.
+ */
+ migrate_disable();
+ curcpu = smp_processor_id();
+ for_each_online_cpu(cpu) {
+ struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
+ struct mem_cgroup *memcg;
+ bool flush = false;
+
+ rcu_read_lock();
+ memcg = READ_ONCE(stock->cached);
+ if (memcg && stock->nr_pages &&
+ mem_cgroup_is_descendant(memcg, root_memcg))
+ flush = true;
+ else if (obj_stock_flush_required(stock, root_memcg))
+ flush = true;
+ rcu_read_unlock();
+
+ if (flush &&
+ !test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
+ if (cpu == curcpu)
+ drain_local_stock(&stock->work);
+ else if (!cpu_is_isolated(cpu))
+ schedule_work_on(cpu, &stock->work);
+ }
+ }
+ migrate_enable();
+ mutex_unlock(&percpu_charge_mutex);
+}
+
+static int memcg_hotplug_cpu_dead(unsigned int cpu)
+{
+ struct memcg_stock_pcp *stock;
+
+ stock = &per_cpu(memcg_stock, cpu);
+ drain_stock(stock);
+
+ return 0;
+}
+
+static unsigned long reclaim_high(struct mem_cgroup *memcg,
+ unsigned int nr_pages,
+ gfp_t gfp_mask)
+{
+ unsigned long nr_reclaimed = 0;
+
+ do {
+ unsigned long pflags;
+
+ if (page_counter_read(&memcg->memory) <=
+ READ_ONCE(memcg->memory.high))
+ continue;
+
+ memcg_memory_event(memcg, MEMCG_HIGH);
+
+ psi_memstall_enter(&pflags);
+ nr_reclaimed += try_to_free_mem_cgroup_pages(memcg, nr_pages,
+ gfp_mask,
+ MEMCG_RECLAIM_MAY_SWAP);
+ psi_memstall_leave(&pflags);
+ } while ((memcg = parent_mem_cgroup(memcg)) &&
+ !mem_cgroup_is_root(memcg));
+
+ return nr_reclaimed;
+}
+
+static void high_work_func(struct work_struct *work)
+{
+ struct mem_cgroup *memcg;
+
+ memcg = container_of(work, struct mem_cgroup, high_work);
+ reclaim_high(memcg, MEMCG_CHARGE_BATCH, GFP_KERNEL);
+}
+
+/*
+ * Clamp the maximum sleep time per allocation batch to 2 seconds. This is
+ * enough to still cause a significant slowdown in most cases, while still
+ * allowing diagnostics and tracing to proceed without becoming stuck.
+ */
+#define MEMCG_MAX_HIGH_DELAY_JIFFIES (2UL*HZ)
+
+/*
+ * When calculating the delay, we use these either side of the exponentiation to
+ * maintain precision and scale to a reasonable number of jiffies (see the table
+ * below.
+ *
+ * - MEMCG_DELAY_PRECISION_SHIFT: Extra precision bits while translating the
+ * overage ratio to a delay.
+ * - MEMCG_DELAY_SCALING_SHIFT: The number of bits to scale down the
+ * proposed penalty in order to reduce to a reasonable number of jiffies, and
+ * to produce a reasonable delay curve.
+ *
+ * MEMCG_DELAY_SCALING_SHIFT just happens to be a number that produces a
+ * reasonable delay curve compared to precision-adjusted overage, not
+ * penalising heavily at first, but still making sure that growth beyond the
+ * limit penalises misbehaviour cgroups by slowing them down exponentially. For
+ * example, with a high of 100 megabytes:
+ *
+ * +-------+------------------------+
+ * | usage | time to allocate in ms |
+ * +-------+------------------------+
+ * | 100M | 0 |
+ * | 101M | 6 |
+ * | 102M | 25 |
+ * | 103M | 57 |
+ * | 104M | 102 |
+ * | 105M | 159 |
+ * | 106M | 230 |
+ * | 107M | 313 |
+ * | 108M | 409 |
+ * | 109M | 518 |
+ * | 110M | 639 |
+ * | 111M | 774 |
+ * | 112M | 921 |
+ * | 113M | 1081 |
+ * | 114M | 1254 |
+ * | 115M | 1439 |
+ * | 116M | 1638 |
+ * | 117M | 1849 |
+ * | 118M | 2000 |
+ * | 119M | 2000 |
+ * | 120M | 2000 |
+ * +-------+------------------------+
+ */
+ #define MEMCG_DELAY_PRECISION_SHIFT 20
+ #define MEMCG_DELAY_SCALING_SHIFT 14
+
+static u64 calculate_overage(unsigned long usage, unsigned long high)
+{
+ u64 overage;
+
+ if (usage <= high)
+ return 0;
+
+ /*
+ * Prevent division by 0 in overage calculation by acting as if
+ * it was a threshold of 1 page
+ */
+ high = max(high, 1UL);
+
+ overage = usage - high;
+ overage <<= MEMCG_DELAY_PRECISION_SHIFT;
+ return div64_u64(overage, high);
+}
+
+static u64 mem_find_max_overage(struct mem_cgroup *memcg)
+{
+ u64 overage, max_overage = 0;
+
+ do {
+ overage = calculate_overage(page_counter_read(&memcg->memory),
+ READ_ONCE(memcg->memory.high));
+ max_overage = max(overage, max_overage);
+ } while ((memcg = parent_mem_cgroup(memcg)) &&
+ !mem_cgroup_is_root(memcg));
+
+ return max_overage;
+}
+
+static u64 swap_find_max_overage(struct mem_cgroup *memcg)
+{
+ u64 overage, max_overage = 0;
+
+ do {
+ overage = calculate_overage(page_counter_read(&memcg->swap),
+ READ_ONCE(memcg->swap.high));
+ if (overage)
+ memcg_memory_event(memcg, MEMCG_SWAP_HIGH);
+ max_overage = max(overage, max_overage);
+ } while ((memcg = parent_mem_cgroup(memcg)) &&
+ !mem_cgroup_is_root(memcg));
+
+ return max_overage;
+}
+
+/*
+ * Get the number of jiffies that we should penalise a mischievous cgroup which
+ * is exceeding its memory.high by checking both it and its ancestors.
+ */
+static unsigned long calculate_high_delay(struct mem_cgroup *memcg,
+ unsigned int nr_pages,
+ u64 max_overage)
+{
+ unsigned long penalty_jiffies;
+
+ if (!max_overage)
+ return 0;
+
+ /*
+ * We use overage compared to memory.high to calculate the number of
+ * jiffies to sleep (penalty_jiffies). Ideally this value should be
+ * fairly lenient on small overages, and increasingly harsh when the
+ * memcg in question makes it clear that it has no intention of stopping
+ * its crazy behaviour, so we exponentially increase the delay based on
+ * overage amount.
+ */
+ penalty_jiffies = max_overage * max_overage * HZ;
+ penalty_jiffies >>= MEMCG_DELAY_PRECISION_SHIFT;
+ penalty_jiffies >>= MEMCG_DELAY_SCALING_SHIFT;
+
+ /*
+ * Factor in the task's own contribution to the overage, such that four
+ * N-sized allocations are throttled approximately the same as one
+ * 4N-sized allocation.
+ *
+ * MEMCG_CHARGE_BATCH pages is nominal, so work out how much smaller or
+ * larger the current charge patch is than that.
+ */
+ return penalty_jiffies * nr_pages / MEMCG_CHARGE_BATCH;
+}
+
+/*
+ * Scheduled by try_charge() to be executed from the userland return path
+ * and reclaims memory over the high limit.
+ */
+void mem_cgroup_handle_over_high(gfp_t gfp_mask)
+{
+ unsigned long penalty_jiffies;
+ unsigned long pflags;
+ unsigned long nr_reclaimed;
+ unsigned int nr_pages = current->memcg_nr_pages_over_high;
+ int nr_retries = MAX_RECLAIM_RETRIES;
+ struct mem_cgroup *memcg;
+ bool in_retry = false;
+
+ if (likely(!nr_pages))
+ return;
+
+ memcg = get_mem_cgroup_from_mm(current->mm);
+ current->memcg_nr_pages_over_high = 0;
+
+retry_reclaim:
+ /*
+ * The allocating task should reclaim at least the batch size, but for
+ * subsequent retries we only want to do what's necessary to prevent oom
+ * or breaching resource isolation.
+ *
+ * This is distinct from memory.max or page allocator behaviour because
+ * memory.high is currently batched, whereas memory.max and the page
+ * allocator run every time an allocation is made.
+ */
+ nr_reclaimed = reclaim_high(memcg,
+ in_retry ? SWAP_CLUSTER_MAX : nr_pages,
+ gfp_mask);
+
+ /*
+ * memory.high is breached and reclaim is unable to keep up. Throttle
+ * allocators proactively to slow down excessive growth.
+ */
+ penalty_jiffies = calculate_high_delay(memcg, nr_pages,
+ mem_find_max_overage(memcg));
+
+ penalty_jiffies += calculate_high_delay(memcg, nr_pages,
+ swap_find_max_overage(memcg));
+
+ /*
+ * Clamp the max delay per usermode return so as to still keep the
+ * application moving forwards and also permit diagnostics, albeit
+ * extremely slowly.
+ */
+ penalty_jiffies = min(penalty_jiffies, MEMCG_MAX_HIGH_DELAY_JIFFIES);
+
+ /*
+ * Don't sleep if the amount of jiffies this memcg owes us is so low
+ * that it's not even worth doing, in an attempt to be nice to those who
+ * go only a small amount over their memory.high value and maybe haven't
+ * been aggressively reclaimed enough yet.
+ */
+ if (penalty_jiffies <= HZ / 100)
+ goto out;
+
+ /*
+ * If reclaim is making forward progress but we're still over
+ * memory.high, we want to encourage that rather than doing allocator
+ * throttling.
+ */
+ if (nr_reclaimed || nr_retries--) {
+ in_retry = true;
+ goto retry_reclaim;
+ }
+
+ /*
+ * If we exit early, we're guaranteed to die (since
+ * schedule_timeout_killable sets TASK_KILLABLE). This means we don't
+ * need to account for any ill-begotten jiffies to pay them off later.
+ */
+ psi_memstall_enter(&pflags);
+ schedule_timeout_killable(penalty_jiffies);
+ psi_memstall_leave(&pflags);
+
+out:
+ css_put(&memcg->css);
+}
+
+static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
+ unsigned int nr_pages)
+{
+ unsigned int batch = max(MEMCG_CHARGE_BATCH, nr_pages);
+ int nr_retries = MAX_RECLAIM_RETRIES;
+ struct mem_cgroup *mem_over_limit;
+ struct page_counter *counter;
+ unsigned long nr_reclaimed;
+ bool passed_oom = false;
+ unsigned int reclaim_options = MEMCG_RECLAIM_MAY_SWAP;
+ bool drained = false;
+ bool raised_max_event = false;
+ unsigned long pflags;
+
+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);
+ reclaim_options &= ~MEMCG_RECLAIM_MAY_SWAP;
+ }
+
+ if (batch > nr_pages) {
+ batch = nr_pages;
+ goto retry;
+ }
+
+ /*
+ * Prevent unbounded recursion when reclaim operations need to
+ * allocate memory. This might exceed the limits temporarily,
+ * but we prefer facilitating memory reclaim and getting back
+ * under the limit over triggering OOM kills in these cases.
+ */
+ if (unlikely(current->flags & PF_MEMALLOC))
+ goto force;
+
+ 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);
+ raised_max_event = true;
+
+ psi_memstall_enter(&pflags);
+ nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages,
+ gfp_mask, reclaim_options);
+ psi_memstall_leave(&pflags);
+
+ if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
+ goto retry;
+
+ if (!drained) {
+ drain_all_stock(mem_over_limit);
+ drained = true;
+ goto retry;
+ }
+
+ if (gfp_mask & __GFP_NORETRY)
+ goto nomem;
+ /*
+ * Even though the limit is exceeded at this point, reclaim
+ * may have been able to free some pages. Retry the charge
+ * before killing the task.
+ *
+ * Only for regular pages, though: huge pages are rather
+ * unlikely to succeed so close to the limit, and we fall back
+ * to regular pages anyway in case of failure.
+ */
+ if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER))
+ goto retry;
+ /*
+ * At task move, charge accounts can be doubly counted. So, it's
+ * better to wait until the end of task_move if something is going on.
+ */
+ if (mem_cgroup_wait_acct_move(mem_over_limit))
+ goto retry;
+
+ if (nr_retries--)
+ goto retry;
+
+ if (gfp_mask & __GFP_RETRY_MAYFAIL)
+ goto nomem;
+
+ /* Avoid endless loop for tasks bypassed by the oom killer */
+ if (passed_oom && task_is_dying())
+ goto nomem;
+
+ /*
+ * keep retrying as long as the memcg oom killer is able to make
+ * a forward progress or bypass the charge if the oom killer
+ * couldn't make any progress.
+ */
+ if (mem_cgroup_oom(mem_over_limit, gfp_mask,
+ get_order(nr_pages * PAGE_SIZE))) {
+ passed_oom = true;
+ nr_retries = MAX_RECLAIM_RETRIES;
+ goto retry;
+ }
+nomem:
+ /*
+ * Memcg doesn't have a dedicated reserve for atomic
+ * allocations. But like the global atomic pool, we need to
+ * put the burden of reclaim on regular allocation requests
+ * and let these go through as privileged allocations.
+ */
+ if (!(gfp_mask & (__GFP_NOFAIL | __GFP_HIGH)))
+ return -ENOMEM;
+force:
+ /*
+ * If the allocation has to be enforced, don't forget to raise
+ * a MEMCG_MAX event.
+ */
+ if (!raised_max_event)
+ memcg_memory_event(mem_over_limit, MEMCG_MAX);
+
+ /*
+ * The allocation either can't fail or will lead to more memory
+ * being freed very soon. Allow memory usage go over the limit
+ * temporarily by force charging it.
+ */
+ page_counter_charge(&memcg->memory, nr_pages);
+ if (do_memsw_account())
+ page_counter_charge(&memcg->memsw, nr_pages);
+
+ return 0;
+
+done_restock:
+ if (batch > nr_pages)
+ refill_stock(memcg, batch - nr_pages);
+
+ /*
+ * If the hierarchy is above the normal consumption range, schedule
+ * reclaim on returning to userland. We can perform reclaim here
+ * if __GFP_RECLAIM but let's always punt for simplicity and so that
+ * GFP_KERNEL can consistently be used during reclaim. @memcg is
+ * not recorded as it most likely matches current's and won't
+ * change in the meantime. As high limit is checked again before
+ * reclaim, the cost of mismatch is negligible.
+ */
+ do {
+ bool mem_high, swap_high;
+
+ mem_high = page_counter_read(&memcg->memory) >
+ READ_ONCE(memcg->memory.high);
+ swap_high = page_counter_read(&memcg->swap) >
+ READ_ONCE(memcg->swap.high);
+
+ /* Don't bother a random interrupted task */
+ if (!in_task()) {
+ if (mem_high) {
+ schedule_work(&memcg->high_work);
+ break;
+ }
+ continue;
+ }
+
+ if (mem_high || swap_high) {
+ /*
+ * The allocating tasks in this cgroup will need to do
+ * reclaim or be throttled to prevent further growth
+ * of the memory or swap footprints.
+ *
+ * Target some best-effort fairness between the tasks,
+ * and distribute reclaim work and delay penalties
+ * based on how much each task is actually allocating.
+ */
+ current->memcg_nr_pages_over_high += batch;
+ set_notify_resume(current);
+ break;
+ }
+ } while ((memcg = parent_mem_cgroup(memcg)));
+
+ if (current->memcg_nr_pages_over_high > MEMCG_CHARGE_BATCH &&
+ !(current->flags & PF_MEMALLOC) &&
+ gfpflags_allow_blocking(gfp_mask)) {
+ mem_cgroup_handle_over_high(gfp_mask);
+ }
+ return 0;
+}
+
+static inline int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
+ unsigned int nr_pages)
+{
+ if (mem_cgroup_is_root(memcg))
+ return 0;
+
+ return try_charge_memcg(memcg, gfp_mask, nr_pages);
+}
+
+static inline 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);
+}
+
+static void commit_charge(struct folio *folio, struct mem_cgroup *memcg)
+{
+ VM_BUG_ON_FOLIO(folio_memcg(folio), folio);
+ /*
+ * Any of the following ensures page's memcg stability:
+ *
+ * - the page lock
+ * - LRU isolation
+ * - folio_memcg_lock()
+ * - exclusive reference
+ * - mem_cgroup_trylock_pages()
+ */
+ folio->memcg_data = (unsigned long)memcg;
+}
+
+#ifdef CONFIG_MEMCG_KMEM
+/*
+ * The allocated objcg pointers array is not accounted directly.
+ * Moreover, it should not come from DMA buffer and is not readily
+ * reclaimable. So those GFP bits should be masked off.
+ */
+#define OBJCGS_CLEAR_MASK (__GFP_DMA | __GFP_RECLAIMABLE | \
+ __GFP_ACCOUNT | __GFP_NOFAIL)
+
+/*
+ * mod_objcg_mlstate() may be called with irq enabled, so
+ * mod_memcg_lruvec_state() should be used.
+ */
+static inline void mod_objcg_mlstate(struct obj_cgroup *objcg,
+ struct pglist_data *pgdat,
+ enum node_stat_item idx, int nr)
+{
+ struct mem_cgroup *memcg;
+ struct lruvec *lruvec;
+
+ rcu_read_lock();
+ memcg = obj_cgroup_memcg(objcg);
+ lruvec = mem_cgroup_lruvec(memcg, pgdat);
+ mod_memcg_lruvec_state(lruvec, idx, nr);
+ rcu_read_unlock();
+}
+
+int memcg_alloc_slab_cgroups(struct slab *slab, struct kmem_cache *s,
+ gfp_t gfp, bool new_slab)
+{
+ unsigned int objects = objs_per_slab(s, slab);
+ unsigned long memcg_data;
+ void *vec;
+
+ gfp &= ~OBJCGS_CLEAR_MASK;
+ vec = kcalloc_node(objects, sizeof(struct obj_cgroup *), gfp,
+ slab_nid(slab));
+ if (!vec)
+ return -ENOMEM;
+
+ memcg_data = (unsigned long) vec | MEMCG_DATA_OBJCGS;
+ if (new_slab) {
+ /*
+ * If the slab is brand new and nobody can yet access its
+ * memcg_data, no synchronization is required and memcg_data can
+ * be simply assigned.
+ */
+ slab->memcg_data = memcg_data;
+ } else if (cmpxchg(&slab->memcg_data, 0, memcg_data)) {
+ /*
+ * If the slab is already in use, somebody can allocate and
+ * assign obj_cgroups in parallel. In this case the existing
+ * objcg vector should be reused.
+ */
+ kfree(vec);
+ return 0;
+ }
+
+ kmemleak_not_leak(vec);
+ return 0;
+}
+
+static __always_inline
+struct mem_cgroup *mem_cgroup_from_obj_folio(struct folio *folio, void *p)
+{
+ /*
+ * Slab objects are accounted individually, not per-page.
+ * Memcg membership data for each individual object is saved in
+ * slab->memcg_data.
+ */
+ if (folio_test_slab(folio)) {
+ struct obj_cgroup **objcgs;
+ struct slab *slab;
+ unsigned int off;
+
+ slab = folio_slab(folio);
+ objcgs = slab_objcgs(slab);
+ if (!objcgs)
+ return NULL;
+
+ off = obj_to_index(slab->slab_cache, slab, p);
+ if (objcgs[off])
+ return obj_cgroup_memcg(objcgs[off]);
+
+ return NULL;
+ }
+
+ /*
+ * folio_memcg_check() is used here, because in theory we can encounter
+ * a folio where the slab flag has been cleared already, but
+ * slab->memcg_data has not been freed yet
+ * folio_memcg_check() will guarantee that a proper memory
+ * cgroup pointer or NULL will be returned.
+ */
+ return folio_memcg_check(folio);
+}
+
+/*
+ * Returns a pointer to the memory cgroup to which the kernel object is charged.
+ *
+ * A passed kernel object can be a slab object, vmalloc object or a generic
+ * kernel page, so different mechanisms for getting the memory cgroup pointer
+ * should be used.
+ *
+ * In certain cases (e.g. kernel stacks or large kmallocs with SLUB) the caller
+ * can not know for sure how the kernel object is implemented.
+ * mem_cgroup_from_obj() can be safely used in such cases.
+ *
+ * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(),
+ * cgroup_mutex, etc.
+ */
+struct mem_cgroup *mem_cgroup_from_obj(void *p)
+{
+ struct folio *folio;
+
+ if (mem_cgroup_disabled())
+ return NULL;
+
+ if (unlikely(is_vmalloc_addr(p)))
+ folio = page_folio(vmalloc_to_page(p));
+ else
+ folio = virt_to_folio(p);
+
+ return mem_cgroup_from_obj_folio(folio, p);
+}
+
+/*
+ * Returns a pointer to the memory cgroup to which the kernel object is charged.
+ * Similar to mem_cgroup_from_obj(), but faster and not suitable for objects,
+ * allocated using vmalloc().
+ *
+ * A passed kernel object must be a slab object or a generic kernel page.
+ *
+ * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(),
+ * cgroup_mutex, etc.
+ */
+struct mem_cgroup *mem_cgroup_from_slab_obj(void *p)
+{
+ if (mem_cgroup_disabled())
+ return NULL;
+
+ return mem_cgroup_from_obj_folio(virt_to_folio(p), p);
+}
+
+static struct obj_cgroup *__get_obj_cgroup_from_memcg(struct mem_cgroup *memcg)
+{
+ struct obj_cgroup *objcg = NULL;
+
+ for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) {
+ objcg = rcu_dereference(memcg->objcg);
+ if (objcg && obj_cgroup_tryget(objcg))
+ break;
+ objcg = NULL;
+ }
+ return objcg;
+}
+
+__always_inline struct obj_cgroup *get_obj_cgroup_from_current(void)
+{
+ struct obj_cgroup *objcg = NULL;
+ struct mem_cgroup *memcg;
+
+ if (memcg_kmem_bypass())
+ return NULL;
+
+ rcu_read_lock();
+ if (unlikely(active_memcg()))
+ memcg = active_memcg();
+ else
+ memcg = mem_cgroup_from_task(current);
+ objcg = __get_obj_cgroup_from_memcg(memcg);
+ rcu_read_unlock();
+ return objcg;
+}
+
+struct obj_cgroup *get_obj_cgroup_from_folio(struct folio *folio)
+{
+ struct obj_cgroup *objcg;
+
+ if (!memcg_kmem_online())
+ return NULL;
+
+ if (folio_memcg_kmem(folio)) {
+ objcg = __folio_objcg(folio);
+ obj_cgroup_get(objcg);
+ } else {
+ struct mem_cgroup *memcg;
+
+ rcu_read_lock();
+ memcg = __folio_memcg(folio);
+ if (memcg)
+ objcg = __get_obj_cgroup_from_memcg(memcg);
+ else
+ objcg = NULL;
+ rcu_read_unlock();
+ }
+ return objcg;
+}
+
+static void memcg_account_kmem(struct mem_cgroup *memcg, int nr_pages)
+{
+ mod_memcg_state(memcg, MEMCG_KMEM, nr_pages);
+ if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
+ if (nr_pages > 0)
+ page_counter_charge(&memcg->kmem, nr_pages);
+ else
+ page_counter_uncharge(&memcg->kmem, -nr_pages);
+ }
+}
+
+
+/*
+ * obj_cgroup_uncharge_pages: uncharge a number of kernel pages from a objcg
+ * @objcg: object cgroup to uncharge
+ * @nr_pages: number of pages to uncharge
+ */
+static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg,
+ unsigned int nr_pages)
+{
+ struct mem_cgroup *memcg;
+
+ memcg = get_mem_cgroup_from_objcg(objcg);
+
+ memcg_account_kmem(memcg, -nr_pages);
+ refill_stock(memcg, nr_pages);
+
+ css_put(&memcg->css);
+}
+
+/*
+ * obj_cgroup_charge_pages: charge a number of kernel pages to a objcg
+ * @objcg: object cgroup to charge
+ * @gfp: reclaim mode
+ * @nr_pages: number of pages to charge
+ *
+ * Returns 0 on success, an error code on failure.
+ */
+static int obj_cgroup_charge_pages(struct obj_cgroup *objcg, gfp_t gfp,
+ unsigned int nr_pages)
+{
+ struct mem_cgroup *memcg;
+ int ret;
+
+ memcg = get_mem_cgroup_from_objcg(objcg);
+
+ ret = try_charge_memcg(memcg, gfp, nr_pages);
+ if (ret)
+ goto out;
+
+ memcg_account_kmem(memcg, nr_pages);
+out:
+ css_put(&memcg->css);
+
+ return ret;
+}
+
+/**
+ * __memcg_kmem_charge_page: charge a kmem page to the current memory cgroup
+ * @page: page to charge
+ * @gfp: reclaim mode
+ * @order: allocation order
+ *
+ * Returns 0 on success, an error code on failure.
+ */
+int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order)
+{
+ struct obj_cgroup *objcg;
+ int ret = 0;
+
+ objcg = get_obj_cgroup_from_current();
+ if (objcg) {
+ ret = obj_cgroup_charge_pages(objcg, gfp, 1 << order);
+ if (!ret) {
+ page->memcg_data = (unsigned long)objcg |
+ MEMCG_DATA_KMEM;
+ return 0;
+ }
+ obj_cgroup_put(objcg);
+ }
+ return ret;
+}
+
+/**
+ * __memcg_kmem_uncharge_page: uncharge a kmem page
+ * @page: page to uncharge
+ * @order: allocation order
+ */
+void __memcg_kmem_uncharge_page(struct page *page, int order)
+{
+ struct folio *folio = page_folio(page);
+ struct obj_cgroup *objcg;
+ unsigned int nr_pages = 1 << order;
+
+ if (!folio_memcg_kmem(folio))
+ return;
+
+ objcg = __folio_objcg(folio);
+ obj_cgroup_uncharge_pages(objcg, nr_pages);
+ folio->memcg_data = 0;
+ obj_cgroup_put(objcg);
+}
+
+void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
+ enum node_stat_item idx, int nr)
+{
+ struct memcg_stock_pcp *stock;
+ struct obj_cgroup *old = NULL;
+ unsigned long flags;
+ int *bytes;
+
+ local_lock_irqsave(&memcg_stock.stock_lock, flags);
+ stock = this_cpu_ptr(&memcg_stock);
+
+ /*
+ * Save vmstat data in stock and skip vmstat array update unless
+ * accumulating over a page of vmstat data or when pgdat or idx
+ * changes.
+ */
+ if (READ_ONCE(stock->cached_objcg) != objcg) {
+ old = drain_obj_stock(stock);
+ obj_cgroup_get(objcg);
+ stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
+ ? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
+ WRITE_ONCE(stock->cached_objcg, objcg);
+ stock->cached_pgdat = pgdat;
+ } else if (stock->cached_pgdat != pgdat) {
+ /* Flush the existing cached vmstat data */
+ struct pglist_data *oldpg = stock->cached_pgdat;
+
+ if (stock->nr_slab_reclaimable_b) {
+ mod_objcg_mlstate(objcg, oldpg, NR_SLAB_RECLAIMABLE_B,
+ stock->nr_slab_reclaimable_b);
+ stock->nr_slab_reclaimable_b = 0;
+ }
+ if (stock->nr_slab_unreclaimable_b) {
+ mod_objcg_mlstate(objcg, oldpg, NR_SLAB_UNRECLAIMABLE_B,
+ stock->nr_slab_unreclaimable_b);
+ stock->nr_slab_unreclaimable_b = 0;
+ }
+ stock->cached_pgdat = pgdat;
+ }
+
+ bytes = (idx == NR_SLAB_RECLAIMABLE_B) ? &stock->nr_slab_reclaimable_b
+ : &stock->nr_slab_unreclaimable_b;
+ /*
+ * Even for large object >= PAGE_SIZE, the vmstat data will still be
+ * cached locally at least once before pushing it out.
+ */
+ if (!*bytes) {
+ *bytes = nr;
+ nr = 0;
+ } else {
+ *bytes += nr;
+ if (abs(*bytes) > PAGE_SIZE) {
+ nr = *bytes;
+ *bytes = 0;
+ } else {
+ nr = 0;
+ }
+ }
+ if (nr)
+ mod_objcg_mlstate(objcg, pgdat, idx, nr);
+
+ local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
+ if (old)
+ obj_cgroup_put(old);
+}
+
+static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
+{
+ struct memcg_stock_pcp *stock;
+ unsigned long flags;
+ bool ret = false;
+
+ local_lock_irqsave(&memcg_stock.stock_lock, flags);
+
+ stock = this_cpu_ptr(&memcg_stock);
+ if (objcg == READ_ONCE(stock->cached_objcg) && stock->nr_bytes >= nr_bytes) {
+ stock->nr_bytes -= nr_bytes;
+ ret = true;
+ }
+
+ local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
+
+ return ret;
+}
+
+static struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock)
+{
+ struct obj_cgroup *old = READ_ONCE(stock->cached_objcg);
+
+ if (!old)
+ return NULL;
+
+ if (stock->nr_bytes) {
+ unsigned int nr_pages = stock->nr_bytes >> PAGE_SHIFT;
+ unsigned int nr_bytes = stock->nr_bytes & (PAGE_SIZE - 1);
+
+ if (nr_pages) {
+ struct mem_cgroup *memcg;
+
+ memcg = get_mem_cgroup_from_objcg(old);
+
+ memcg_account_kmem(memcg, -nr_pages);
+ __refill_stock(memcg, nr_pages);
+
+ css_put(&memcg->css);
+ }
+
+ /*
+ * The leftover is flushed to the centralized per-memcg value.
+ * On the next attempt to refill obj stock it will be moved
+ * to a per-cpu stock (probably, on an other CPU), see
+ * refill_obj_stock().
+ *
+ * How often it's flushed is a trade-off between the memory
+ * limit enforcement accuracy and potential CPU contention,
+ * so it might be changed in the future.
+ */
+ atomic_add(nr_bytes, &old->nr_charged_bytes);
+ stock->nr_bytes = 0;
+ }
+
+ /*
+ * Flush the vmstat data in current stock
+ */
+ if (stock->nr_slab_reclaimable_b || stock->nr_slab_unreclaimable_b) {
+ if (stock->nr_slab_reclaimable_b) {
+ mod_objcg_mlstate(old, stock->cached_pgdat,
+ NR_SLAB_RECLAIMABLE_B,
+ stock->nr_slab_reclaimable_b);
+ stock->nr_slab_reclaimable_b = 0;
+ }
+ if (stock->nr_slab_unreclaimable_b) {
+ mod_objcg_mlstate(old, stock->cached_pgdat,
+ NR_SLAB_UNRECLAIMABLE_B,
+ stock->nr_slab_unreclaimable_b);
+ stock->nr_slab_unreclaimable_b = 0;
+ }
+ stock->cached_pgdat = NULL;
+ }
+
+ WRITE_ONCE(stock->cached_objcg, NULL);
+ /*
+ * The `old' objects needs to be released by the caller via
+ * obj_cgroup_put() outside of memcg_stock_pcp::stock_lock.
+ */
+ return old;
+}
+
+static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
+ struct mem_cgroup *root_memcg)
+{
+ struct obj_cgroup *objcg = READ_ONCE(stock->cached_objcg);
+ struct mem_cgroup *memcg;
+
+ if (objcg) {
+ memcg = obj_cgroup_memcg(objcg);
+ if (memcg && mem_cgroup_is_descendant(memcg, root_memcg))
+ return true;
+ }
+
+ return false;
+}
+
+static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes,
+ bool allow_uncharge)
+{
+ struct memcg_stock_pcp *stock;
+ struct obj_cgroup *old = NULL;
+ unsigned long flags;
+ unsigned int nr_pages = 0;
+
+ local_lock_irqsave(&memcg_stock.stock_lock, flags);
+
+ stock = this_cpu_ptr(&memcg_stock);
+ if (READ_ONCE(stock->cached_objcg) != objcg) { /* reset if necessary */
+ old = drain_obj_stock(stock);
+ obj_cgroup_get(objcg);
+ WRITE_ONCE(stock->cached_objcg, objcg);
+ stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
+ ? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
+ allow_uncharge = true; /* Allow uncharge when objcg changes */
+ }
+ stock->nr_bytes += nr_bytes;
+
+ if (allow_uncharge && (stock->nr_bytes > PAGE_SIZE)) {
+ nr_pages = stock->nr_bytes >> PAGE_SHIFT;
+ stock->nr_bytes &= (PAGE_SIZE - 1);
+ }
+
+ local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
+ if (old)
+ obj_cgroup_put(old);
+
+ if (nr_pages)
+ obj_cgroup_uncharge_pages(objcg, nr_pages);
+}
+
+int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size)
+{
+ unsigned int nr_pages, nr_bytes;
+ int ret;
+
+ if (consume_obj_stock(objcg, size))
+ return 0;
+
+ /*
+ * In theory, objcg->nr_charged_bytes can have enough
+ * pre-charged bytes to satisfy the allocation. However,
+ * flushing objcg->nr_charged_bytes requires two atomic
+ * operations, and objcg->nr_charged_bytes can't be big.
+ * The shared objcg->nr_charged_bytes can also become a
+ * performance bottleneck if all tasks of the same memcg are
+ * trying to update it. So it's better to ignore it and try
+ * grab some new pages. The stock's nr_bytes will be flushed to
+ * objcg->nr_charged_bytes later on when objcg changes.
+ *
+ * The stock's nr_bytes may contain enough pre-charged bytes
+ * to allow one less page from being charged, but we can't rely
+ * on the pre-charged bytes not being changed outside of
+ * consume_obj_stock() or refill_obj_stock(). So ignore those
+ * pre-charged bytes as well when charging pages. To avoid a
+ * page uncharge right after a page charge, we set the
+ * allow_uncharge flag to false when calling refill_obj_stock()
+ * to temporarily allow the pre-charged bytes to exceed the page
+ * size limit. The maximum reachable value of the pre-charged
+ * bytes is (sizeof(object) + PAGE_SIZE - 2) if there is no data
+ * race.
+ */
+ nr_pages = size >> PAGE_SHIFT;
+ nr_bytes = size & (PAGE_SIZE - 1);
+
+ if (nr_bytes)
+ nr_pages += 1;
+
+ ret = obj_cgroup_charge_pages(objcg, gfp, nr_pages);
+ if (!ret && nr_bytes)
+ refill_obj_stock(objcg, PAGE_SIZE - nr_bytes, false);
+
+ return ret;
+}
+
+void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size)
+{
+ refill_obj_stock(objcg, size, true);
+}
+
+#endif /* CONFIG_MEMCG_KMEM */
+
+/*
+ * Because page_memcg(head) is not set on tails, set it now.
+ */
+void split_page_memcg(struct page *head, unsigned int nr)
+{
+ struct folio *folio = page_folio(head);
+ struct mem_cgroup *memcg = folio_memcg(folio);
+ int i;
+
+ if (mem_cgroup_disabled() || !memcg)
+ return;
+
+ for (i = 1; i < nr; i++)
+ folio_page(folio, i)->memcg_data = folio->memcg_data;
+
+ if (folio_memcg_kmem(folio))
+ obj_cgroup_get_many(__folio_objcg(folio), nr - 1);
+ else
+ css_get_many(&memcg->css, nr - 1);
+}
+
+#ifdef CONFIG_SWAP
+/**
+ * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
+ * @entry: swap entry to be moved
+ * @from: mem_cgroup which the entry is moved from
+ * @to: mem_cgroup which the entry is moved to
+ *
+ * It succeeds only when the swap_cgroup's record for this entry is the same
+ * as the mem_cgroup's id of @from.
+ *
+ * Returns 0 on success, -EINVAL on failure.
+ *
+ * The caller must have charged to @to, IOW, called page_counter_charge() about
+ * both res and memsw, and called css_get().
+ */
+static int mem_cgroup_move_swap_account(swp_entry_t entry,
+ struct mem_cgroup *from, struct mem_cgroup *to)
+{
+ unsigned short old_id, new_id;
+
+ old_id = mem_cgroup_id(from);
+ new_id = mem_cgroup_id(to);
+
+ if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
+ mod_memcg_state(from, MEMCG_SWAP, -1);
+ mod_memcg_state(to, MEMCG_SWAP, 1);
+ return 0;
+ }
+ return -EINVAL;
+}
+#else
+static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
+ struct mem_cgroup *from, struct mem_cgroup *to)
+{
+ return -EINVAL;
+}
+#endif
+
+static DEFINE_MUTEX(memcg_max_mutex);
+
+static int mem_cgroup_resize_max(struct mem_cgroup *memcg,
+ unsigned long max, bool memsw)
+{
+ bool enlarge = false;
+ bool drained = false;
+ int ret;
+ bool limits_invariant;
+ struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;
+
+ do {
+ if (signal_pending(current)) {
+ ret = -EINTR;
+ break;
+ }
+
+ mutex_lock(&memcg_max_mutex);
+ /*
+ * Make sure that the new limit (memsw or memory limit) doesn't
+ * break our basic invariant rule memory.max <= memsw.max.
+ */
+ limits_invariant = memsw ? max >= READ_ONCE(memcg->memory.max) :
+ max <= memcg->memsw.max;
+ if (!limits_invariant) {
+ mutex_unlock(&memcg_max_mutex);
+ ret = -EINVAL;
+ break;
+ }
+ if (max > counter->max)
+ enlarge = true;
+ ret = page_counter_set_max(counter, max);
+ mutex_unlock(&memcg_max_mutex);
+
+ if (!ret)
+ break;
+
+ if (!drained) {
+ drain_all_stock(memcg);
+ drained = true;
+ continue;
+ }
+
+ if (!try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL,
+ memsw ? 0 : MEMCG_RECLAIM_MAY_SWAP)) {
+ 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;
+
+ if (lru_gen_enabled())
+ return 0;
+
+ if (order > 0)
+ return 0;
+
+ mctz = soft_limit_tree.rb_tree_per_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;
+
+ reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat,
+ gfp_mask, total_scanned);
+ nr_reclaimed += reclaimed;
+ spin_lock_irq(&mctz->lock);
+
+ /*
+ * If we failed to reclaim anything from this memory cgroup
+ * it is time to move on to the next cgroup
+ */
+ next_mz = NULL;
+ if (!reclaimed)
+ next_mz = __mem_cgroup_largest_soft_limit_node(mctz);
+
+ excess = soft_limit_excess(mz->memcg);
+ /*
+ * One school of thought says that we should not add
+ * back the node to the tree if reclaim returns 0.
+ * But our reclaim could return 0, simply because due
+ * to priority we are exposing a smaller subset of
+ * memory to reclaim from. Consider this as a longer
+ * term TODO.
+ */
+ /* If excess == 0, no tree ops */
+ __mem_cgroup_insert_exceeded(mz, mctz, excess);
+ spin_unlock_irq(&mctz->lock);
+ css_put(&mz->memcg->css);
+ loop++;
+ /*
+ * Could not reclaim anything and there are no more
+ * mem cgroups to try or we seem to be looping without
+ * reclaiming anything.
+ */
+ if (!nr_reclaimed &&
+ (next_mz == NULL ||
+ loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
+ break;
+ } while (!nr_reclaimed);
+ if (next_mz)
+ css_put(&next_mz->memcg->css);
+ return nr_reclaimed;
+}
+
+/*
+ * Reclaims as many pages from the given memcg as possible.
+ *
+ * Caller is responsible for holding css reference for memcg.
+ */
+static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
+{
+ int nr_retries = MAX_RECLAIM_RETRIES;
+
+ /* we call try-to-free pages for make this cgroup empty */
+ lru_add_drain_all();
+
+ drain_all_stock(memcg);
+
+ /* try to free all pages in this cgroup */
+ while (nr_retries && page_counter_read(&memcg->memory)) {
+ if (signal_pending(current))
+ return -EINTR;
+
+ if (!try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL,
+ MEMCG_RECLAIM_MAY_SWAP))
+ nr_retries--;
+ }
+
+ return 0;
+}
+
+static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes,
+ loff_t off)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+
+ if (mem_cgroup_is_root(memcg))
+ return -EINVAL;
+ return mem_cgroup_force_empty(memcg) ?: nbytes;
+}
+
+static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
+ struct cftype *cft)
+{
+ return 1;
+}
+
+static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
+ struct cftype *cft, u64 val)
+{
+ if (val == 1)
+ return 0;
+
+ pr_warn_once("Non-hierarchical mode is deprecated. "
+ "Please report your usecase to linux-mm@kvack.org if you "
+ "depend on this functionality.\n");
+
+ return -EINVAL;
+}
+
+static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
+{
+ unsigned long val;
+
+ if (mem_cgroup_is_root(memcg)) {
+ /*
+ * Approximate root's usage from global state. This isn't
+ * perfect, but the root usage was always an approximation.
+ */
+ val = global_node_page_state(NR_FILE_PAGES) +
+ global_node_page_state(NR_ANON_MAPPED);
+ if (swap)
+ val += total_swap_pages - get_nr_swap_pages();
+ } else {
+ if (!swap)
+ val = page_counter_read(&memcg->memory);
+ else
+ val = page_counter_read(&memcg->memsw);
+ }
+ return val;
+}
+
+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)READ_ONCE(memcg->soft_limit) * PAGE_SIZE;
+ default:
+ BUG();
+ }
+}
+
+/*
+ * This function doesn't do anything useful. Its only job is to provide a read
+ * handler for a file so that cgroup_file_mode() will add read permissions.
+ */
+static int mem_cgroup_dummy_seq_show(__always_unused struct seq_file *m,
+ __always_unused void *v)
+{
+ return -EINVAL;
+}
+
+#ifdef CONFIG_MEMCG_KMEM
+static int memcg_online_kmem(struct mem_cgroup *memcg)
+{
+ struct obj_cgroup *objcg;
+
+ if (mem_cgroup_kmem_disabled())
+ return 0;
+
+ if (unlikely(mem_cgroup_is_root(memcg)))
+ return 0;
+
+ objcg = obj_cgroup_alloc();
+ if (!objcg)
+ return -ENOMEM;
+
+ objcg->memcg = memcg;
+ rcu_assign_pointer(memcg->objcg, objcg);
+
+ static_branch_enable(&memcg_kmem_online_key);
+
+ memcg->kmemcg_id = memcg->id.id;
+
+ return 0;
+}
+
+static void memcg_offline_kmem(struct mem_cgroup *memcg)
+{
+ struct mem_cgroup *parent;
+
+ if (mem_cgroup_kmem_disabled())
+ return;
+
+ if (unlikely(mem_cgroup_is_root(memcg)))
+ return;
+
+ parent = parent_mem_cgroup(memcg);
+ if (!parent)
+ parent = root_mem_cgroup;
+
+ memcg_reparent_objcgs(memcg, parent);
+
+ /*
+ * After we have finished memcg_reparent_objcgs(), all list_lrus
+ * corresponding to this cgroup are guaranteed to remain empty.
+ * The ordering is imposed by list_lru_node->lock taken by
+ * memcg_reparent_list_lrus().
+ */
+ memcg_reparent_list_lrus(memcg, parent);
+}
+#else
+static int memcg_online_kmem(struct mem_cgroup *memcg)
+{
+ return 0;
+}
+static void memcg_offline_kmem(struct mem_cgroup *memcg)
+{
+}
+#endif /* CONFIG_MEMCG_KMEM */
+
+static int memcg_update_tcp_max(struct mem_cgroup *memcg, unsigned long max)
+{
+ int ret;
+
+ mutex_lock(&memcg_max_mutex);
+
+ ret = page_counter_set_max(&memcg->tcpmem, max);
+ if (ret)
+ goto out;
+
+ if (!memcg->tcpmem_active) {
+ /*
+ * The active flag needs to be written after the static_key
+ * update. This is what guarantees that the socket activation
+ * function is the last one to run. See mem_cgroup_sk_alloc()
+ * for details, and note that we don't mark any socket as
+ * belonging to this memcg until that flag is up.
+ *
+ * We need to do this, because static_keys will span multiple
+ * sites, but we can't control their order. If we mark a socket
+ * as accounted, but the accounting functions are not patched in
+ * yet, we'll lose accounting.
+ *
+ * We never race with the readers in mem_cgroup_sk_alloc(),
+ * because when this value change, the code to process it is not
+ * patched in yet.
+ */
+ static_branch_inc(&memcg_sockets_enabled_key);
+ memcg->tcpmem_active = true;
+ }
+out:
+ mutex_unlock(&memcg_max_mutex);
+ return ret;
+}
+
+/*
+ * The user of this function is...
+ * RES_LIMIT.
+ */
+static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+ unsigned long nr_pages;
+ int ret;
+
+ buf = strstrip(buf);
+ ret = page_counter_memparse(buf, "-1", &nr_pages);
+ if (ret)
+ return ret;
+
+ switch (MEMFILE_ATTR(of_cft(of)->private)) {
+ case RES_LIMIT:
+ if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
+ ret = -EINVAL;
+ break;
+ }
+ switch (MEMFILE_TYPE(of_cft(of)->private)) {
+ case _MEM:
+ ret = mem_cgroup_resize_max(memcg, nr_pages, false);
+ break;
+ case _MEMSWAP:
+ ret = mem_cgroup_resize_max(memcg, nr_pages, true);
+ break;
+ case _KMEM:
+ pr_warn_once("kmem.limit_in_bytes is deprecated and will be removed. "
+ "Writing any value to this file has no effect. "
+ "Please report your usecase to linux-mm@kvack.org if you "
+ "depend on this functionality.\n");
+ ret = 0;
+ break;
+ case _TCP:
+ ret = memcg_update_tcp_max(memcg, nr_pages);
+ break;
+ }
+ break;
+ case RES_SOFT_LIMIT:
+ if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
+ ret = -EOPNOTSUPP;
+ } else {
+ WRITE_ONCE(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);
+
+ pr_warn_once("Cgroup memory moving (move_charge_at_immigrate) is deprecated. "
+ "Please report your usecase to linux-mm@kvack.org if you "
+ "depend on this functionality.\n");
+
+ if (val & ~MOVE_MASK)
+ return -EINVAL;
+
+ /*
+ * No kind of locking is needed in here, because ->can_attach() will
+ * check this value once in the beginning of the process, and then carry
+ * on with stale data. This means that changes to this value will only
+ * affect task migrations starting after the change.
+ */
+ memcg->move_charge_at_immigrate = val;
+ return 0;
+}
+#else
+static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
+ struct cftype *cft, u64 val)
+{
+ return -ENOSYS;
+}
+#endif
+
+#ifdef CONFIG_NUMA
+
+#define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE))
+#define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON))
+#define LRU_ALL ((1 << NR_LRU_LISTS) - 1)
+
+static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
+ int nid, unsigned int lru_mask, bool tree)
+{
+ struct lruvec *lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
+ unsigned long nr = 0;
+ enum lru_list lru;
+
+ VM_BUG_ON((unsigned)nid >= nr_node_ids);
+
+ for_each_lru(lru) {
+ if (!(BIT(lru) & lru_mask))
+ continue;
+ if (tree)
+ nr += lruvec_page_state(lruvec, NR_LRU_BASE + lru);
+ else
+ nr += lruvec_page_state_local(lruvec, NR_LRU_BASE + lru);
+ }
+ return nr;
+}
+
+static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
+ unsigned int lru_mask,
+ bool tree)
+{
+ unsigned long nr = 0;
+ enum lru_list lru;
+
+ for_each_lru(lru) {
+ if (!(BIT(lru) & lru_mask))
+ continue;
+ if (tree)
+ nr += memcg_page_state(memcg, NR_LRU_BASE + lru);
+ else
+ nr += memcg_page_state_local(memcg, NR_LRU_BASE + lru);
+ }
+ return nr;
+}
+
+static int memcg_numa_stat_show(struct seq_file *m, void *v)
+{
+ struct numa_stat {
+ const char *name;
+ unsigned int lru_mask;
+ };
+
+ static const struct numa_stat stats[] = {
+ { "total", LRU_ALL },
+ { "file", LRU_ALL_FILE },
+ { "anon", LRU_ALL_ANON },
+ { "unevictable", BIT(LRU_UNEVICTABLE) },
+ };
+ const struct numa_stat *stat;
+ int nid;
+ struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
+
+ mem_cgroup_flush_stats();
+
+ for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
+ seq_printf(m, "%s=%lu", stat->name,
+ mem_cgroup_nr_lru_pages(memcg, stat->lru_mask,
+ false));
+ for_each_node_state(nid, N_MEMORY)
+ seq_printf(m, " N%d=%lu", nid,
+ mem_cgroup_node_nr_lru_pages(memcg, nid,
+ stat->lru_mask, false));
+ seq_putc(m, '\n');
+ }
+
+ for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
+
+ seq_printf(m, "hierarchical_%s=%lu", stat->name,
+ mem_cgroup_nr_lru_pages(memcg, stat->lru_mask,
+ true));
+ for_each_node_state(nid, N_MEMORY)
+ seq_printf(m, " N%d=%lu", nid,
+ mem_cgroup_node_nr_lru_pages(memcg, nid,
+ stat->lru_mask, true));
+ seq_putc(m, '\n');
+ }
+
+ return 0;
+}
+#endif /* CONFIG_NUMA */
+
+static const unsigned int memcg1_stats[] = {
+ NR_FILE_PAGES,
+ NR_ANON_MAPPED,
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ NR_ANON_THPS,
+#endif
+ NR_SHMEM,
+ NR_FILE_MAPPED,
+ NR_FILE_DIRTY,
+ NR_WRITEBACK,
+ WORKINGSET_REFAULT_ANON,
+ WORKINGSET_REFAULT_FILE,
+ MEMCG_SWAP,
+};
+
+static const char *const memcg1_stat_names[] = {
+ "cache",
+ "rss",
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ "rss_huge",
+#endif
+ "shmem",
+ "mapped_file",
+ "dirty",
+ "writeback",
+ "workingset_refault_anon",
+ "workingset_refault_file",
+ "swap",
+};
+
+/* Universal VM events cgroup1 shows, original sort order */
+static const unsigned int memcg1_events[] = {
+ PGPGIN,
+ PGPGOUT,
+ PGFAULT,
+ PGMAJFAULT,
+};
+
+static void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s)
+{
+ unsigned long memory, memsw;
+ struct mem_cgroup *mi;
+ unsigned int i;
+
+ BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats));
+
+ mem_cgroup_flush_stats();
+
+ for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
+ unsigned long nr;
+
+ if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
+ continue;
+ nr = memcg_page_state_local(memcg, memcg1_stats[i]);
+ seq_buf_printf(s, "%s %lu\n", memcg1_stat_names[i],
+ nr * memcg_page_state_unit(memcg1_stats[i]));
+ }
+
+ for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
+ seq_buf_printf(s, "%s %lu\n", vm_event_name(memcg1_events[i]),
+ memcg_events_local(memcg, memcg1_events[i]));
+
+ for (i = 0; i < NR_LRU_LISTS; i++)
+ seq_buf_printf(s, "%s %lu\n", lru_list_name(i),
+ memcg_page_state_local(memcg, NR_LRU_BASE + i) *
+ PAGE_SIZE);
+
+ /* Hierarchical information */
+ memory = memsw = PAGE_COUNTER_MAX;
+ for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) {
+ memory = min(memory, READ_ONCE(mi->memory.max));
+ memsw = min(memsw, READ_ONCE(mi->memsw.max));
+ }
+ seq_buf_printf(s, "hierarchical_memory_limit %llu\n",
+ (u64)memory * PAGE_SIZE);
+ if (do_memsw_account())
+ seq_buf_printf(s, "hierarchical_memsw_limit %llu\n",
+ (u64)memsw * PAGE_SIZE);
+
+ for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
+ unsigned long nr;
+
+ if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
+ continue;
+ nr = memcg_page_state(memcg, memcg1_stats[i]);
+ seq_buf_printf(s, "total_%s %llu\n", memcg1_stat_names[i],
+ (u64)nr * memcg_page_state_unit(memcg1_stats[i]));
+ }
+
+ for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
+ seq_buf_printf(s, "total_%s %llu\n",
+ vm_event_name(memcg1_events[i]),
+ (u64)memcg_events(memcg, memcg1_events[i]));
+
+ for (i = 0; i < NR_LRU_LISTS; i++)
+ seq_buf_printf(s, "total_%s %llu\n", lru_list_name(i),
+ (u64)memcg_page_state(memcg, NR_LRU_BASE + i) *
+ PAGE_SIZE);
+
+#ifdef CONFIG_DEBUG_VM
+ {
+ pg_data_t *pgdat;
+ struct mem_cgroup_per_node *mz;
+ unsigned long anon_cost = 0;
+ unsigned long file_cost = 0;
+
+ for_each_online_pgdat(pgdat) {
+ mz = memcg->nodeinfo[pgdat->node_id];
+
+ anon_cost += mz->lruvec.anon_cost;
+ file_cost += mz->lruvec.file_cost;
+ }
+ seq_buf_printf(s, "anon_cost %lu\n", anon_cost);
+ seq_buf_printf(s, "file_cost %lu\n", file_cost);
+ }
+#endif
+}
+
+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 > 200)
+ return -EINVAL;
+
+ if (!mem_cgroup_is_root(memcg))
+ WRITE_ONCE(memcg->swappiness, val);
+ else
+ WRITE_ONCE(vm_swappiness, val);
+
+ return 0;
+}
+
+static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
+{
+ struct mem_cgroup_threshold_ary *t;
+ unsigned long usage;
+ int i;
+
+ rcu_read_lock();
+ if (!swap)
+ t = rcu_dereference(memcg->thresholds.primary);
+ else
+ t = rcu_dereference(memcg->memsw_thresholds.primary);
+
+ if (!t)
+ goto unlock;
+
+ usage = mem_cgroup_usage(memcg, swap);
+
+ /*
+ * current_threshold points to threshold just below or equal to usage.
+ * If it's not true, a threshold was crossed after last
+ * call of __mem_cgroup_threshold().
+ */
+ i = t->current_threshold;
+
+ /*
+ * Iterate backward over array of thresholds starting from
+ * current_threshold and check if a threshold is crossed.
+ * If none of thresholds below usage is crossed, we read
+ * only one element of the array here.
+ */
+ for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
+ eventfd_signal(t->entries[i].eventfd, 1);
+
+ /* i = current_threshold + 1 */
+ i++;
+
+ /*
+ * Iterate forward over array of thresholds starting from
+ * current_threshold+1 and check if a threshold is crossed.
+ * If none of thresholds above usage is crossed, we read
+ * only one element of the array here.
+ */
+ for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
+ eventfd_signal(t->entries[i].eventfd, 1);
+
+ /* Update current_threshold */
+ t->current_threshold = i - 1;
+unlock:
+ rcu_read_unlock();
+}
+
+static void mem_cgroup_threshold(struct mem_cgroup *memcg)
+{
+ while (memcg) {
+ __mem_cgroup_threshold(memcg, false);
+ if (do_memsw_account())
+ __mem_cgroup_threshold(memcg, true);
+
+ memcg = parent_mem_cgroup(memcg);
+ }
+}
+
+static int compare_thresholds(const void *a, const void *b)
+{
+ const struct mem_cgroup_threshold *_a = a;
+ const struct mem_cgroup_threshold *_b = b;
+
+ if (_a->threshold > _b->threshold)
+ return 1;
+
+ if (_a->threshold < _b->threshold)
+ return -1;
+
+ return 0;
+}
+
+static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
+{
+ struct mem_cgroup_eventfd_list *ev;
+
+ spin_lock(&memcg_oom_lock);
+
+ list_for_each_entry(ev, &memcg->oom_notify, list)
+ eventfd_signal(ev->eventfd, 1);
+
+ spin_unlock(&memcg_oom_lock);
+ return 0;
+}
+
+static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
+{
+ struct mem_cgroup *iter;
+
+ for_each_mem_cgroup_tree(iter, memcg)
+ mem_cgroup_oom_notify_cb(iter);
+}
+
+static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
+ struct eventfd_ctx *eventfd, const char *args, enum res_type type)
+{
+ struct mem_cgroup_thresholds *thresholds;
+ struct mem_cgroup_threshold_ary *new;
+ unsigned long threshold;
+ unsigned long usage;
+ int i, size, ret;
+
+ ret = page_counter_memparse(args, "-1", &threshold);
+ if (ret)
+ return ret;
+
+ mutex_lock(&memcg->thresholds_lock);
+
+ if (type == _MEM) {
+ thresholds = &memcg->thresholds;
+ usage = mem_cgroup_usage(memcg, false);
+ } else if (type == _MEMSWAP) {
+ thresholds = &memcg->memsw_thresholds;
+ usage = mem_cgroup_usage(memcg, true);
+ } else
+ BUG();
+
+ /* Check if a threshold crossed before adding a new one */
+ if (thresholds->primary)
+ __mem_cgroup_threshold(memcg, type == _MEMSWAP);
+
+ size = thresholds->primary ? thresholds->primary->size + 1 : 1;
+
+ /* Allocate memory for new array of thresholds */
+ new = kmalloc(struct_size(new, entries, size), GFP_KERNEL);
+ if (!new) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+ new->size = size;
+
+ /* Copy thresholds (if any) to new array */
+ if (thresholds->primary)
+ memcpy(new->entries, thresholds->primary->entries,
+ flex_array_size(new, entries, size - 1));
+
+ /* Add new threshold */
+ new->entries[size - 1].eventfd = eventfd;
+ new->entries[size - 1].threshold = threshold;
+
+ /* Sort thresholds. Registering of new threshold isn't time-critical */
+ sort(new->entries, size, sizeof(*new->entries),
+ compare_thresholds, NULL);
+
+ /* Find current threshold */
+ new->current_threshold = -1;
+ for (i = 0; i < size; i++) {
+ if (new->entries[i].threshold <= usage) {
+ /*
+ * new->current_threshold will not be used until
+ * rcu_assign_pointer(), so it's safe to increment
+ * it here.
+ */
+ ++new->current_threshold;
+ } else
+ break;
+ }
+
+ /* Free old spare buffer and save old primary buffer as spare */
+ kfree(thresholds->spare);
+ thresholds->spare = thresholds->primary;
+
+ rcu_assign_pointer(thresholds->primary, new);
+
+ /* To be sure that nobody uses thresholds */
+ synchronize_rcu();
+
+unlock:
+ mutex_unlock(&memcg->thresholds_lock);
+
+ return ret;
+}
+
+static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
+ struct eventfd_ctx *eventfd, const char *args)
+{
+ return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM);
+}
+
+static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg,
+ struct eventfd_ctx *eventfd, const char *args)
+{
+ return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP);
+}
+
+static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
+ struct eventfd_ctx *eventfd, enum res_type type)
+{
+ struct mem_cgroup_thresholds *thresholds;
+ struct mem_cgroup_threshold_ary *new;
+ unsigned long usage;
+ int i, j, size, entries;
+
+ mutex_lock(&memcg->thresholds_lock);
+
+ if (type == _MEM) {
+ thresholds = &memcg->thresholds;
+ usage = mem_cgroup_usage(memcg, false);
+ } else if (type == _MEMSWAP) {
+ thresholds = &memcg->memsw_thresholds;
+ usage = mem_cgroup_usage(memcg, true);
+ } else
+ BUG();
+
+ if (!thresholds->primary)
+ goto unlock;
+
+ /* Check if a threshold crossed before removing */
+ __mem_cgroup_threshold(memcg, type == _MEMSWAP);
+
+ /* Calculate new number of threshold */
+ size = entries = 0;
+ for (i = 0; i < thresholds->primary->size; i++) {
+ if (thresholds->primary->entries[i].eventfd != eventfd)
+ size++;
+ else
+ entries++;
+ }
+
+ new = thresholds->spare;
+
+ /* If no items related to eventfd have been cleared, nothing to do */
+ if (!entries)
+ goto unlock;
+
+ /* Set thresholds array to NULL if we don't have thresholds */
+ if (!size) {
+ kfree(new);
+ new = NULL;
+ goto swap_buffers;
+ }
+
+ new->size = size;
+
+ /* Copy thresholds and find current threshold */
+ new->current_threshold = -1;
+ for (i = 0, j = 0; i < thresholds->primary->size; i++) {
+ if (thresholds->primary->entries[i].eventfd == eventfd)
+ continue;
+
+ new->entries[j] = thresholds->primary->entries[i];
+ if (new->entries[j].threshold <= usage) {
+ /*
+ * new->current_threshold will not be used
+ * until rcu_assign_pointer(), so it's safe to increment
+ * it here.
+ */
+ ++new->current_threshold;
+ }
+ j++;
+ }
+
+swap_buffers:
+ /* Swap primary and spare array */
+ thresholds->spare = thresholds->primary;
+
+ rcu_assign_pointer(thresholds->primary, new);
+
+ /* To be sure that nobody uses thresholds */
+ synchronize_rcu();
+
+ /* If all events are unregistered, free the spare array */
+ if (!new) {
+ kfree(thresholds->spare);
+ thresholds->spare = NULL;
+ }
+unlock:
+ mutex_unlock(&memcg->thresholds_lock);
+}
+
+static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
+ struct eventfd_ctx *eventfd)
+{
+ return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM);
+}
+
+static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
+ struct eventfd_ctx *eventfd)
+{
+ return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP);
+}
+
+static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
+ struct eventfd_ctx *eventfd, const char *args)
+{
+ struct mem_cgroup_eventfd_list *event;
+
+ event = kmalloc(sizeof(*event), GFP_KERNEL);
+ if (!event)
+ return -ENOMEM;
+
+ spin_lock(&memcg_oom_lock);
+
+ event->eventfd = eventfd;
+ list_add(&event->list, &memcg->oom_notify);
+
+ /* already in OOM ? */
+ if (memcg->under_oom)
+ eventfd_signal(eventfd, 1);
+ spin_unlock(&memcg_oom_lock);
+
+ return 0;
+}
+
+static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg,
+ struct eventfd_ctx *eventfd)
+{
+ struct mem_cgroup_eventfd_list *ev, *tmp;
+
+ spin_lock(&memcg_oom_lock);
+
+ list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
+ if (ev->eventfd == eventfd) {
+ list_del(&ev->list);
+ kfree(ev);
+ }
+ }
+
+ spin_unlock(&memcg_oom_lock);
+}
+
+static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_seq(sf);
+
+ seq_printf(sf, "oom_kill_disable %d\n", READ_ONCE(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 (mem_cgroup_is_root(memcg) || !((val == 0) || (val == 1)))
+ return -EINVAL;
+
+ WRITE_ONCE(memcg->oom_kill_disable, val);
+ if (!val)
+ memcg_oom_recover(memcg);
+
+ return 0;
+}
+
+#ifdef CONFIG_CGROUP_WRITEBACK
+
+#include <trace/events/writeback.h>
+
+static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
+{
+ return wb_domain_init(&memcg->cgwb_domain, gfp);
+}
+
+static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
+{
+ wb_domain_exit(&memcg->cgwb_domain);
+}
+
+static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
+{
+ wb_domain_size_changed(&memcg->cgwb_domain);
+}
+
+struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
+
+ if (!memcg->css.parent)
+ return NULL;
+
+ return &memcg->cgwb_domain;
+}
+
+/**
+ * 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;
+
+ mem_cgroup_flush_stats();
+
+ *pdirty = memcg_page_state(memcg, NR_FILE_DIRTY);
+ *pwriteback = memcg_page_state(memcg, NR_WRITEBACK);
+ *pfilepages = memcg_page_state(memcg, NR_INACTIVE_FILE) +
+ memcg_page_state(memcg, NR_ACTIVE_FILE);
+
+ *pheadroom = PAGE_COUNTER_MAX;
+ while ((parent = parent_mem_cgroup(memcg))) {
+ unsigned long ceiling = min(READ_ONCE(memcg->memory.max),
+ READ_ONCE(memcg->memory.high));
+ unsigned long used = page_counter_read(&memcg->memory);
+
+ *pheadroom = min(*pheadroom, ceiling - min(ceiling, used));
+ memcg = parent;
+ }
+}
+
+/*
+ * Foreign dirty flushing
+ *
+ * There's an inherent mismatch between memcg and writeback. The former
+ * tracks ownership per-page while the latter per-inode. This was a
+ * deliberate design decision because honoring per-page ownership in the
+ * writeback path is complicated, may lead to higher CPU and IO overheads
+ * and deemed unnecessary given that write-sharing an inode across
+ * different cgroups isn't a common use-case.
+ *
+ * Combined with inode majority-writer ownership switching, this works well
+ * enough in most cases but there are some pathological cases. For
+ * example, let's say there are two cgroups A and B which keep writing to
+ * different but confined parts of the same inode. B owns the inode and
+ * A's memory is limited far below B's. A's dirty ratio can rise enough to
+ * trigger balance_dirty_pages() sleeps but B's can be low enough to avoid
+ * triggering background writeback. A will be slowed down without a way to
+ * make writeback of the dirty pages happen.
+ *
+ * Conditions like the above can lead to a cgroup getting repeatedly and
+ * severely throttled after making some progress after each
+ * dirty_expire_interval while the underlying IO device is almost
+ * completely idle.
+ *
+ * Solving this problem completely requires matching the ownership tracking
+ * granularities between memcg and writeback in either direction. However,
+ * the more egregious behaviors can be avoided by simply remembering the
+ * most recent foreign dirtying events and initiating remote flushes on
+ * them when local writeback isn't enough to keep the memory clean enough.
+ *
+ * The following two functions implement such mechanism. When a foreign
+ * page - a page whose memcg and writeback ownerships don't match - is
+ * dirtied, mem_cgroup_track_foreign_dirty() records the inode owning
+ * bdi_writeback on the page owning memcg. When balance_dirty_pages()
+ * decides that the memcg needs to sleep due to high dirty ratio, it calls
+ * mem_cgroup_flush_foreign() which queues writeback on the recorded
+ * foreign bdi_writebacks which haven't expired. Both the numbers of
+ * recorded bdi_writebacks and concurrent in-flight foreign writebacks are
+ * limited to MEMCG_CGWB_FRN_CNT.
+ *
+ * The mechanism only remembers IDs and doesn't hold any object references.
+ * As being wrong occasionally doesn't matter, updates and accesses to the
+ * records are lockless and racy.
+ */
+void mem_cgroup_track_foreign_dirty_slowpath(struct folio *folio,
+ struct bdi_writeback *wb)
+{
+ struct mem_cgroup *memcg = folio_memcg(folio);
+ struct memcg_cgwb_frn *frn;
+ u64 now = get_jiffies_64();
+ u64 oldest_at = now;
+ int oldest = -1;
+ int i;
+
+ trace_track_foreign_dirty(folio, wb);
+
+ /*
+ * Pick the slot to use. If there is already a slot for @wb, keep
+ * using it. If not replace the oldest one which isn't being
+ * written out.
+ */
+ for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) {
+ frn = &memcg->cgwb_frn[i];
+ if (frn->bdi_id == wb->bdi->id &&
+ frn->memcg_id == wb->memcg_css->id)
+ break;
+ if (time_before64(frn->at, oldest_at) &&
+ atomic_read(&frn->done.cnt) == 1) {
+ oldest = i;
+ oldest_at = frn->at;
+ }
+ }
+
+ if (i < MEMCG_CGWB_FRN_CNT) {
+ /*
+ * Re-using an existing one. Update timestamp lazily to
+ * avoid making the cacheline hot. We want them to be
+ * reasonably up-to-date and significantly shorter than
+ * dirty_expire_interval as that's what expires the record.
+ * Use the shorter of 1s and dirty_expire_interval / 8.
+ */
+ unsigned long update_intv =
+ min_t(unsigned long, HZ,
+ msecs_to_jiffies(dirty_expire_interval * 10) / 8);
+
+ if (time_before64(frn->at, now - update_intv))
+ frn->at = now;
+ } else if (oldest >= 0) {
+ /* replace the oldest free one */
+ frn = &memcg->cgwb_frn[oldest];
+ frn->bdi_id = wb->bdi->id;
+ frn->memcg_id = wb->memcg_css->id;
+ frn->at = now;
+ }
+}
+
+/* issue foreign writeback flushes for recorded foreign dirtying events */
+void mem_cgroup_flush_foreign(struct bdi_writeback *wb)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
+ unsigned long intv = msecs_to_jiffies(dirty_expire_interval * 10);
+ u64 now = jiffies_64;
+ int i;
+
+ for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) {
+ struct memcg_cgwb_frn *frn = &memcg->cgwb_frn[i];
+
+ /*
+ * If the record is older than dirty_expire_interval,
+ * writeback on it has already started. No need to kick it
+ * off again. Also, don't start a new one if there's
+ * already one in flight.
+ */
+ if (time_after64(frn->at, now - intv) &&
+ atomic_read(&frn->done.cnt) == 1) {
+ frn->at = 0;
+ trace_flush_foreign(wb, frn->bdi_id, frn->memcg_id);
+ cgroup_writeback_by_id(frn->bdi_id, frn->memcg_id,
+ WB_REASON_FOREIGN_FLUSH,
+ &frn->done);
+ }
+ }
+}
+
+#else /* CONFIG_CGROUP_WRITEBACK */
+
+static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
+{
+ return 0;
+}
+
+static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
+{
+}
+
+static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
+{
+}
+
+#endif /* CONFIG_CGROUP_WRITEBACK */
+
+/*
+ * DO NOT USE IN NEW FILES.
+ *
+ * "cgroup.event_control" implementation.
+ *
+ * This is way over-engineered. It tries to support fully configurable
+ * events for each user. Such level of flexibility is completely
+ * unnecessary especially in the light of the planned unified hierarchy.
+ *
+ * Please deprecate this and replace with something simpler if at all
+ * possible.
+ */
+
+/*
+ * Unregister event and free resources.
+ *
+ * Gets called from workqueue.
+ */
+static void memcg_event_remove(struct work_struct *work)
+{
+ struct mem_cgroup_event *event =
+ container_of(work, struct mem_cgroup_event, remove);
+ struct mem_cgroup *memcg = event->memcg;
+
+ remove_wait_queue(event->wqh, &event->wait);
+
+ event->unregister_event(memcg, event->eventfd);
+
+ /* Notify userspace the event is going away. */
+ eventfd_signal(event->eventfd, 1);
+
+ eventfd_ctx_put(event->eventfd);
+ kfree(event);
+ css_put(&memcg->css);
+}
+
+/*
+ * Gets called on EPOLLHUP on eventfd when user closes it.
+ *
+ * Called with wqh->lock held and interrupts disabled.
+ */
+static int memcg_event_wake(wait_queue_entry_t *wait, unsigned mode,
+ int sync, void *key)
+{
+ struct mem_cgroup_event *event =
+ container_of(wait, struct mem_cgroup_event, wait);
+ struct mem_cgroup *memcg = event->memcg;
+ __poll_t flags = key_to_poll(key);
+
+ if (flags & EPOLLHUP) {
+ /*
+ * If the event has been detached at cgroup removal, we
+ * can simply return knowing the other side will cleanup
+ * for us.
+ *
+ * We can't race against event freeing since the other
+ * side will require wqh->lock via remove_wait_queue(),
+ * which we hold.
+ */
+ spin_lock(&memcg->event_list_lock);
+ if (!list_empty(&event->list)) {
+ list_del_init(&event->list);
+ /*
+ * We are in atomic context, but cgroup_event_remove()
+ * may sleep, so we have to call it in workqueue.
+ */
+ schedule_work(&event->remove);
+ }
+ spin_unlock(&memcg->event_list_lock);
+ }
+
+ return 0;
+}
+
+static void memcg_event_ptable_queue_proc(struct file *file,
+ wait_queue_head_t *wqh, poll_table *pt)
+{
+ struct mem_cgroup_event *event =
+ container_of(pt, struct mem_cgroup_event, pt);
+
+ event->wqh = wqh;
+ add_wait_queue(wqh, &event->wait);
+}
+
+/*
+ * DO NOT USE IN NEW FILES.
+ *
+ * Parse input and register new cgroup event handler.
+ *
+ * Input must be in format '<event_fd> <control_fd> <args>'.
+ * Interpretation of args is defined by control file implementation.
+ */
+static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct cgroup_subsys_state *css = of_css(of);
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+ struct mem_cgroup_event *event;
+ struct cgroup_subsys_state *cfile_css;
+ unsigned int efd, cfd;
+ struct fd efile;
+ struct fd cfile;
+ struct dentry *cdentry;
+ const char *name;
+ char *endp;
+ int ret;
+
+ if (IS_ENABLED(CONFIG_PREEMPT_RT))
+ return -EOPNOTSUPP;
+
+ buf = strstrip(buf);
+
+ efd = simple_strtoul(buf, &endp, 10);
+ if (*endp != ' ')
+ return -EINVAL;
+ buf = endp + 1;
+
+ cfd = simple_strtoul(buf, &endp, 10);
+ if ((*endp != ' ') && (*endp != '\0'))
+ return -EINVAL;
+ buf = endp + 1;
+
+ event = kzalloc(sizeof(*event), GFP_KERNEL);
+ if (!event)
+ return -ENOMEM;
+
+ event->memcg = memcg;
+ INIT_LIST_HEAD(&event->list);
+ init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc);
+ init_waitqueue_func_entry(&event->wait, memcg_event_wake);
+ INIT_WORK(&event->remove, memcg_event_remove);
+
+ efile = fdget(efd);
+ if (!efile.file) {
+ ret = -EBADF;
+ goto out_kfree;
+ }
+
+ event->eventfd = eventfd_ctx_fileget(efile.file);
+ if (IS_ERR(event->eventfd)) {
+ ret = PTR_ERR(event->eventfd);
+ goto out_put_efile;
+ }
+
+ cfile = fdget(cfd);
+ if (!cfile.file) {
+ ret = -EBADF;
+ goto out_put_eventfd;
+ }
+
+ /* the process need read permission on control file */
+ /* AV: shouldn't we check that it's been opened for read instead? */
+ ret = file_permission(cfile.file, MAY_READ);
+ if (ret < 0)
+ goto out_put_cfile;
+
+ /*
+ * The control file must be a regular cgroup1 file. As a regular cgroup
+ * file can't be renamed, it's safe to access its name afterwards.
+ */
+ cdentry = cfile.file->f_path.dentry;
+ if (cdentry->d_sb->s_type != &cgroup_fs_type || !d_is_reg(cdentry)) {
+ ret = -EINVAL;
+ 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 = cdentry->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(cdentry->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_irq(&memcg->event_list_lock);
+ list_add(&event->list, &memcg->event_list);
+ spin_unlock_irq(&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;
+}
+
+#if defined(CONFIG_MEMCG_KMEM) && (defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG))
+static int mem_cgroup_slab_show(struct seq_file *m, void *p)
+{
+ /*
+ * Deprecated.
+ * Please, take a look at tools/cgroup/memcg_slabinfo.py .
+ */
+ return 0;
+}
+#endif
+
+static int memory_stat_show(struct seq_file *m, void *v);
+
+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 = memory_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,
+ },
+ {
+ .name = "pressure_level",
+ .seq_show = mem_cgroup_dummy_seq_show,
+ },
+#ifdef CONFIG_NUMA
+ {
+ .name = "numa_stat",
+ .seq_show = memcg_numa_stat_show,
+ },
+#endif
+ {
+ .name = "kmem.limit_in_bytes",
+ .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
+ .write = mem_cgroup_write,
+ .read_u64 = mem_cgroup_read_u64,
+ },
+ {
+ .name = "kmem.usage_in_bytes",
+ .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
+ .read_u64 = mem_cgroup_read_u64,
+ },
+ {
+ .name = "kmem.failcnt",
+ .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
+ .write = mem_cgroup_reset,
+ .read_u64 = mem_cgroup_read_u64,
+ },
+ {
+ .name = "kmem.max_usage_in_bytes",
+ .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
+ .write = mem_cgroup_reset,
+ .read_u64 = mem_cgroup_read_u64,
+ },
+#if defined(CONFIG_MEMCG_KMEM) && \
+ (defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG))
+ {
+ .name = "kmem.slabinfo",
+ .seq_show = mem_cgroup_slab_show,
+ },
+#endif
+ {
+ .name = "kmem.tcp.limit_in_bytes",
+ .private = MEMFILE_PRIVATE(_TCP, RES_LIMIT),
+ .write = mem_cgroup_write,
+ .read_u64 = mem_cgroup_read_u64,
+ },
+ {
+ .name = "kmem.tcp.usage_in_bytes",
+ .private = MEMFILE_PRIVATE(_TCP, RES_USAGE),
+ .read_u64 = mem_cgroup_read_u64,
+ },
+ {
+ .name = "kmem.tcp.failcnt",
+ .private = MEMFILE_PRIVATE(_TCP, RES_FAILCNT),
+ .write = mem_cgroup_reset,
+ .read_u64 = mem_cgroup_read_u64,
+ },
+ {
+ .name = "kmem.tcp.max_usage_in_bytes",
+ .private = MEMFILE_PRIVATE(_TCP, RES_MAX_USAGE),
+ .write = mem_cgroup_reset,
+ .read_u64 = mem_cgroup_read_u64,
+ },
+ { }, /* terminate */
+};
+
+/*
+ * Private memory cgroup IDR
+ *
+ * Swap-out records and page cache shadow entries need to store memcg
+ * references in constrained space, so we maintain an ID space that is
+ * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of
+ * memory-controlled cgroups to 64k.
+ *
+ * However, there usually are many references to the offline CSS after
+ * the cgroup has been destroyed, such as page cache or reclaimable
+ * slab objects, that don't need to hang on to the ID. We want to keep
+ * those dead CSS from occupying IDs, or we might quickly exhaust the
+ * relatively small ID space and prevent the creation of new cgroups
+ * even when there are much fewer than 64k cgroups - possibly none.
+ *
+ * Maintain a private 16-bit ID space for memcg, and allow the ID to
+ * be freed and recycled when it's no longer needed, which is usually
+ * when the CSS is offlined.
+ *
+ * The only exception to that are records of swapped out tmpfs/shmem
+ * pages that need to be attributed to live ancestors on swapin. But
+ * those references are manageable from userspace.
+ */
+
+#define MEM_CGROUP_ID_MAX ((1UL << MEM_CGROUP_ID_SHIFT) - 1)
+static DEFINE_IDR(mem_cgroup_idr);
+
+static void mem_cgroup_id_remove(struct mem_cgroup *memcg)
+{
+ if (memcg->id.id > 0) {
+ idr_remove(&mem_cgroup_idr, memcg->id.id);
+ memcg->id.id = 0;
+ }
+}
+
+static void __maybe_unused mem_cgroup_id_get_many(struct mem_cgroup *memcg,
+ unsigned int n)
+{
+ refcount_add(n, &memcg->id.ref);
+}
+
+static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
+{
+ if (refcount_sub_and_test(n, &memcg->id.ref)) {
+ mem_cgroup_id_remove(memcg);
+
+ /* Memcg ID pins CSS */
+ css_put(&memcg->css);
+ }
+}
+
+static inline void mem_cgroup_id_put(struct mem_cgroup *memcg)
+{
+ mem_cgroup_id_put_many(memcg, 1);
+}
+
+/**
+ * mem_cgroup_from_id - look up a memcg from a memcg id
+ * @id: the memcg id to look up
+ *
+ * Caller must hold rcu_read_lock().
+ */
+struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
+{
+ WARN_ON_ONCE(!rcu_read_lock_held());
+ return idr_find(&mem_cgroup_idr, id);
+}
+
+#ifdef CONFIG_SHRINKER_DEBUG
+struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino)
+{
+ struct cgroup *cgrp;
+ struct cgroup_subsys_state *css;
+ struct mem_cgroup *memcg;
+
+ cgrp = cgroup_get_from_id(ino);
+ if (IS_ERR(cgrp))
+ return ERR_CAST(cgrp);
+
+ css = cgroup_get_e_css(cgrp, &memory_cgrp_subsys);
+ if (css)
+ memcg = container_of(css, struct mem_cgroup, css);
+ else
+ memcg = ERR_PTR(-ENOENT);
+
+ cgroup_put(cgrp);
+
+ return memcg;
+}
+#endif
+
+static int alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
+{
+ struct mem_cgroup_per_node *pn;
+
+ pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, node);
+ if (!pn)
+ return 1;
+
+ pn->lruvec_stats_percpu = alloc_percpu_gfp(struct lruvec_stats_percpu,
+ GFP_KERNEL_ACCOUNT);
+ if (!pn->lruvec_stats_percpu) {
+ kfree(pn);
+ return 1;
+ }
+
+ lruvec_init(&pn->lruvec);
+ 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_stats_percpu);
+ 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);
+ kfree(memcg->vmstats);
+ free_percpu(memcg->vmstats_percpu);
+ kfree(memcg);
+}
+
+static void mem_cgroup_free(struct mem_cgroup *memcg)
+{
+ lru_gen_exit_memcg(memcg);
+ memcg_wb_domain_exit(memcg);
+ __mem_cgroup_free(memcg);
+}
+
+static struct mem_cgroup *mem_cgroup_alloc(void)
+{
+ struct mem_cgroup *memcg;
+ int node;
+ int __maybe_unused i;
+ long error = -ENOMEM;
+
+ memcg = kzalloc(struct_size(memcg, nodeinfo, nr_node_ids), GFP_KERNEL);
+ if (!memcg)
+ return ERR_PTR(error);
+
+ memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL,
+ 1, MEM_CGROUP_ID_MAX + 1, GFP_KERNEL);
+ if (memcg->id.id < 0) {
+ error = memcg->id.id;
+ goto fail;
+ }
+
+ memcg->vmstats = kzalloc(sizeof(struct memcg_vmstats), GFP_KERNEL);
+ if (!memcg->vmstats)
+ goto fail;
+
+ memcg->vmstats_percpu = alloc_percpu_gfp(struct memcg_vmstats_percpu,
+ GFP_KERNEL_ACCOUNT);
+ if (!memcg->vmstats_percpu)
+ goto fail;
+
+ for_each_node(node)
+ if (alloc_mem_cgroup_per_node_info(memcg, node))
+ goto fail;
+
+ if (memcg_wb_domain_init(memcg, GFP_KERNEL))
+ goto fail;
+
+ INIT_WORK(&memcg->high_work, high_work_func);
+ INIT_LIST_HEAD(&memcg->oom_notify);
+ mutex_init(&memcg->thresholds_lock);
+ spin_lock_init(&memcg->move_lock);
+ vmpressure_init(&memcg->vmpressure);
+ INIT_LIST_HEAD(&memcg->event_list);
+ spin_lock_init(&memcg->event_list_lock);
+ memcg->socket_pressure = jiffies;
+#ifdef CONFIG_MEMCG_KMEM
+ memcg->kmemcg_id = -1;
+ INIT_LIST_HEAD(&memcg->objcg_list);
+#endif
+#ifdef CONFIG_CGROUP_WRITEBACK
+ INIT_LIST_HEAD(&memcg->cgwb_list);
+ for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++)
+ memcg->cgwb_frn[i].done =
+ __WB_COMPLETION_INIT(&memcg_cgwb_frn_waitq);
+#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ spin_lock_init(&memcg->deferred_split_queue.split_queue_lock);
+ INIT_LIST_HEAD(&memcg->deferred_split_queue.split_queue);
+ memcg->deferred_split_queue.split_queue_len = 0;
+#endif
+ lru_gen_init_memcg(memcg);
+ return memcg;
+fail:
+ mem_cgroup_id_remove(memcg);
+ __mem_cgroup_free(memcg);
+ return ERR_PTR(error);
+}
+
+static struct cgroup_subsys_state * __ref
+mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+ struct mem_cgroup *parent = mem_cgroup_from_css(parent_css);
+ struct mem_cgroup *memcg, *old_memcg;
+
+ old_memcg = set_active_memcg(parent);
+ memcg = mem_cgroup_alloc();
+ set_active_memcg(old_memcg);
+ if (IS_ERR(memcg))
+ return ERR_CAST(memcg);
+
+ page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX);
+ WRITE_ONCE(memcg->soft_limit, PAGE_COUNTER_MAX);
+#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
+ memcg->zswap_max = PAGE_COUNTER_MAX;
+#endif
+ page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX);
+ if (parent) {
+ WRITE_ONCE(memcg->swappiness, mem_cgroup_swappiness(parent));
+ WRITE_ONCE(memcg->oom_kill_disable, READ_ONCE(parent->oom_kill_disable));
+
+ page_counter_init(&memcg->memory, &parent->memory);
+ page_counter_init(&memcg->swap, &parent->swap);
+ page_counter_init(&memcg->kmem, &parent->kmem);
+ page_counter_init(&memcg->tcpmem, &parent->tcpmem);
+ } else {
+ init_memcg_events();
+ page_counter_init(&memcg->memory, NULL);
+ page_counter_init(&memcg->swap, NULL);
+ page_counter_init(&memcg->kmem, NULL);
+ page_counter_init(&memcg->tcpmem, NULL);
+
+ root_mem_cgroup = memcg;
+ return &memcg->css;
+ }
+
+ if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
+ static_branch_inc(&memcg_sockets_enabled_key);
+
+#if defined(CONFIG_MEMCG_KMEM)
+ if (!cgroup_memory_nobpf)
+ static_branch_inc(&memcg_bpf_enabled_key);
+#endif
+
+ return &memcg->css;
+}
+
+static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+
+ if (memcg_online_kmem(memcg))
+ goto remove_id;
+
+ /*
+ * A memcg must be visible for expand_shrinker_info()
+ * by the time the maps are allocated. So, we allocate maps
+ * here, when for_each_mem_cgroup() can't skip it.
+ */
+ if (alloc_shrinker_info(memcg))
+ goto offline_kmem;
+
+ if (unlikely(mem_cgroup_is_root(memcg)))
+ queue_delayed_work(system_unbound_wq, &stats_flush_dwork,
+ FLUSH_TIME);
+ lru_gen_online_memcg(memcg);
+
+ /* Online state pins memcg ID, memcg ID pins CSS */
+ refcount_set(&memcg->id.ref, 1);
+ css_get(css);
+
+ /*
+ * Ensure mem_cgroup_from_id() works once we're fully online.
+ *
+ * We could do this earlier and require callers to filter with
+ * css_tryget_online(). But right now there are no users that
+ * need earlier access, and the workingset code relies on the
+ * cgroup tree linkage (mem_cgroup_get_nr_swap_pages()). So
+ * publish it here at the end of onlining. This matches the
+ * regular ID destruction during offlining.
+ */
+ idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
+
+ return 0;
+offline_kmem:
+ memcg_offline_kmem(memcg);
+remove_id:
+ mem_cgroup_id_remove(memcg);
+ return -ENOMEM;
+}
+
+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_irq(&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_irq(&memcg->event_list_lock);
+
+ page_counter_set_min(&memcg->memory, 0);
+ page_counter_set_low(&memcg->memory, 0);
+
+ memcg_offline_kmem(memcg);
+ reparent_shrinker_deferred(memcg);
+ wb_memcg_offline(memcg);
+ lru_gen_offline_memcg(memcg);
+
+ drain_all_stock(memcg);
+
+ mem_cgroup_id_put(memcg);
+}
+
+static void mem_cgroup_css_released(struct cgroup_subsys_state *css)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+
+ invalidate_reclaim_iterators(memcg);
+ lru_gen_release_memcg(memcg);
+}
+
+static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+ int __maybe_unused i;
+
+#ifdef CONFIG_CGROUP_WRITEBACK
+ for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++)
+ wb_wait_for_completion(&memcg->cgwb_frn[i].done);
+#endif
+ if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
+ static_branch_dec(&memcg_sockets_enabled_key);
+
+ if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_active)
+ static_branch_dec(&memcg_sockets_enabled_key);
+
+#if defined(CONFIG_MEMCG_KMEM)
+ if (!cgroup_memory_nobpf)
+ static_branch_dec(&memcg_bpf_enabled_key);
+#endif
+
+ vmpressure_cleanup(&memcg->vmpressure);
+ cancel_work_sync(&memcg->high_work);
+ mem_cgroup_remove_from_trees(memcg);
+ free_shrinker_info(memcg);
+ mem_cgroup_free(memcg);
+}
+
+/**
+ * mem_cgroup_css_reset - reset the states of a mem_cgroup
+ * @css: the target css
+ *
+ * Reset the states of the mem_cgroup associated with @css. This is
+ * invoked when the userland requests disabling on the default hierarchy
+ * but the memcg is pinned through dependency. The memcg should stop
+ * applying policies and should revert to the vanilla state as it may be
+ * made visible again.
+ *
+ * The current implementation only resets the essential configurations.
+ * This needs to be expanded to cover all the visible parts.
+ */
+static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+
+ page_counter_set_max(&memcg->memory, PAGE_COUNTER_MAX);
+ page_counter_set_max(&memcg->swap, PAGE_COUNTER_MAX);
+ page_counter_set_max(&memcg->kmem, PAGE_COUNTER_MAX);
+ page_counter_set_max(&memcg->tcpmem, PAGE_COUNTER_MAX);
+ page_counter_set_min(&memcg->memory, 0);
+ page_counter_set_low(&memcg->memory, 0);
+ page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX);
+ WRITE_ONCE(memcg->soft_limit, PAGE_COUNTER_MAX);
+ page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX);
+ memcg_wb_domain_size_changed(memcg);
+}
+
+static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+ struct mem_cgroup *parent = parent_mem_cgroup(memcg);
+ struct memcg_vmstats_percpu *statc;
+ long delta, delta_cpu, v;
+ int i, nid;
+
+ statc = per_cpu_ptr(memcg->vmstats_percpu, cpu);
+
+ for (i = 0; i < MEMCG_NR_STAT; i++) {
+ /*
+ * Collect the aggregated propagation counts of groups
+ * below us. We're in a per-cpu loop here and this is
+ * a global counter, so the first cycle will get them.
+ */
+ delta = memcg->vmstats->state_pending[i];
+ if (delta)
+ memcg->vmstats->state_pending[i] = 0;
+
+ /* Add CPU changes on this level since the last flush */
+ delta_cpu = 0;
+ v = READ_ONCE(statc->state[i]);
+ if (v != statc->state_prev[i]) {
+ delta_cpu = v - statc->state_prev[i];
+ delta += delta_cpu;
+ statc->state_prev[i] = v;
+ }
+
+ /* Aggregate counts on this level and propagate upwards */
+ if (delta_cpu)
+ memcg->vmstats->state_local[i] += delta_cpu;
+
+ if (delta) {
+ memcg->vmstats->state[i] += delta;
+ if (parent)
+ parent->vmstats->state_pending[i] += delta;
+ }
+ }
+
+ for (i = 0; i < NR_MEMCG_EVENTS; i++) {
+ delta = memcg->vmstats->events_pending[i];
+ if (delta)
+ memcg->vmstats->events_pending[i] = 0;
+
+ delta_cpu = 0;
+ v = READ_ONCE(statc->events[i]);
+ if (v != statc->events_prev[i]) {
+ delta_cpu = v - statc->events_prev[i];
+ delta += delta_cpu;
+ statc->events_prev[i] = v;
+ }
+
+ if (delta_cpu)
+ memcg->vmstats->events_local[i] += delta_cpu;
+
+ if (delta) {
+ memcg->vmstats->events[i] += delta;
+ if (parent)
+ parent->vmstats->events_pending[i] += delta;
+ }
+ }
+
+ for_each_node_state(nid, N_MEMORY) {
+ struct mem_cgroup_per_node *pn = memcg->nodeinfo[nid];
+ struct mem_cgroup_per_node *ppn = NULL;
+ struct lruvec_stats_percpu *lstatc;
+
+ if (parent)
+ ppn = parent->nodeinfo[nid];
+
+ lstatc = per_cpu_ptr(pn->lruvec_stats_percpu, cpu);
+
+ for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
+ delta = pn->lruvec_stats.state_pending[i];
+ if (delta)
+ pn->lruvec_stats.state_pending[i] = 0;
+
+ delta_cpu = 0;
+ v = READ_ONCE(lstatc->state[i]);
+ if (v != lstatc->state_prev[i]) {
+ delta_cpu = v - lstatc->state_prev[i];
+ delta += delta_cpu;
+ lstatc->state_prev[i] = v;
+ }
+
+ if (delta_cpu)
+ pn->lruvec_stats.state_local[i] += delta_cpu;
+
+ if (delta) {
+ pn->lruvec_stats.state[i] += delta;
+ if (ppn)
+ ppn->lruvec_stats.state_pending[i] += delta;
+ }
+ }
+ }
+}
+
+#ifdef CONFIG_MMU
+/* Handlers for move charge at task migration. */
+static int mem_cgroup_do_precharge(unsigned long count)
+{
+ int ret;
+
+ /* Try a single bulk charge without reclaim first, kswapd may wake */
+ ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_DIRECT_RECLAIM, count);
+ if (!ret) {
+ mc.precharge += count;
+ return ret;
+ }
+
+ /* Try charges one by one with reclaim, but do not retry */
+ while (count--) {
+ ret = try_charge(mc.to, GFP_KERNEL | __GFP_NORETRY, 1);
+ if (ret)
+ return ret;
+ mc.precharge++;
+ cond_resched();
+ }
+ return 0;
+}
+
+union mc_target {
+ struct page *page;
+ swp_entry_t ent;
+};
+
+enum mc_target_type {
+ MC_TARGET_NONE = 0,
+ MC_TARGET_PAGE,
+ MC_TARGET_SWAP,
+ MC_TARGET_DEVICE,
+};
+
+static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
+ unsigned long addr, pte_t ptent)
+{
+ struct page *page = vm_normal_page(vma, addr, ptent);
+
+ if (!page)
+ return NULL;
+ if (PageAnon(page)) {
+ if (!(mc.flags & MOVE_ANON))
+ return NULL;
+ } else {
+ if (!(mc.flags & MOVE_FILE))
+ return NULL;
+ }
+ get_page(page);
+
+ return page;
+}
+
+#if defined(CONFIG_SWAP) || defined(CONFIG_DEVICE_PRIVATE)
+static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
+ pte_t ptent, swp_entry_t *entry)
+{
+ struct page *page = NULL;
+ swp_entry_t ent = pte_to_swp_entry(ptent);
+
+ if (!(mc.flags & MOVE_ANON))
+ return NULL;
+
+ /*
+ * Handle device private pages that are not accessible by the CPU, but
+ * stored as special swap entries in the page table.
+ */
+ if (is_device_private_entry(ent)) {
+ page = pfn_swap_entry_to_page(ent);
+ if (!get_page_unless_zero(page))
+ return NULL;
+ return page;
+ }
+
+ if (non_swap_entry(ent))
+ return NULL;
+
+ /*
+ * Because swap_cache_get_folio() updates some statistics counter,
+ * we call find_get_page() with swapper_space directly.
+ */
+ page = find_get_page(swap_address_space(ent), swp_offset(ent));
+ entry->val = ent.val;
+
+ return page;
+}
+#else
+static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
+ pte_t ptent, swp_entry_t *entry)
+{
+ return NULL;
+}
+#endif
+
+static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
+ unsigned long addr, pte_t ptent)
+{
+ unsigned long index;
+ struct folio *folio;
+
+ if (!vma->vm_file) /* anonymous vma */
+ return NULL;
+ if (!(mc.flags & MOVE_FILE))
+ return NULL;
+
+ /* folio is moved even if it's not RSS of this task(page-faulted). */
+ /* shmem/tmpfs may report page out on swap: account for that too. */
+ index = linear_page_index(vma, addr);
+ folio = filemap_get_incore_folio(vma->vm_file->f_mapping, index);
+ if (IS_ERR(folio))
+ return NULL;
+ return folio_file_page(folio, index);
+}
+
+/**
+ * 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 page must be locked and not on the LRU.
+ *
+ * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
+ * from old cgroup.
+ */
+static int mem_cgroup_move_account(struct page *page,
+ bool compound,
+ struct mem_cgroup *from,
+ struct mem_cgroup *to)
+{
+ struct folio *folio = page_folio(page);
+ struct lruvec *from_vec, *to_vec;
+ struct pglist_data *pgdat;
+ unsigned int nr_pages = compound ? folio_nr_pages(folio) : 1;
+ int nid, ret;
+
+ VM_BUG_ON(from == to);
+ VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
+ VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
+ VM_BUG_ON(compound && !folio_test_large(folio));
+
+ ret = -EINVAL;
+ if (folio_memcg(folio) != from)
+ goto out;
+
+ pgdat = folio_pgdat(folio);
+ from_vec = mem_cgroup_lruvec(from, pgdat);
+ to_vec = mem_cgroup_lruvec(to, pgdat);
+
+ folio_memcg_lock(folio);
+
+ if (folio_test_anon(folio)) {
+ if (folio_mapped(folio)) {
+ __mod_lruvec_state(from_vec, NR_ANON_MAPPED, -nr_pages);
+ __mod_lruvec_state(to_vec, NR_ANON_MAPPED, nr_pages);
+ if (folio_test_pmd_mappable(folio)) {
+ __mod_lruvec_state(from_vec, NR_ANON_THPS,
+ -nr_pages);
+ __mod_lruvec_state(to_vec, NR_ANON_THPS,
+ nr_pages);
+ }
+ }
+ } else {
+ __mod_lruvec_state(from_vec, NR_FILE_PAGES, -nr_pages);
+ __mod_lruvec_state(to_vec, NR_FILE_PAGES, nr_pages);
+
+ if (folio_test_swapbacked(folio)) {
+ __mod_lruvec_state(from_vec, NR_SHMEM, -nr_pages);
+ __mod_lruvec_state(to_vec, NR_SHMEM, nr_pages);
+ }
+
+ if (folio_mapped(folio)) {
+ __mod_lruvec_state(from_vec, NR_FILE_MAPPED, -nr_pages);
+ __mod_lruvec_state(to_vec, NR_FILE_MAPPED, nr_pages);
+ }
+
+ if (folio_test_dirty(folio)) {
+ struct address_space *mapping = folio_mapping(folio);
+
+ if (mapping_can_writeback(mapping)) {
+ __mod_lruvec_state(from_vec, NR_FILE_DIRTY,
+ -nr_pages);
+ __mod_lruvec_state(to_vec, NR_FILE_DIRTY,
+ nr_pages);
+ }
+ }
+ }
+
+#ifdef CONFIG_SWAP
+ if (folio_test_swapcache(folio)) {
+ __mod_lruvec_state(from_vec, NR_SWAPCACHE, -nr_pages);
+ __mod_lruvec_state(to_vec, NR_SWAPCACHE, nr_pages);
+ }
+#endif
+ if (folio_test_writeback(folio)) {
+ __mod_lruvec_state(from_vec, NR_WRITEBACK, -nr_pages);
+ __mod_lruvec_state(to_vec, NR_WRITEBACK, nr_pages);
+ }
+
+ /*
+ * All state has been migrated, let's switch to the new memcg.
+ *
+ * It is safe to change page's memcg here because the page
+ * is referenced, charged, isolated, and locked: we can't race
+ * with (un)charging, migration, LRU putback, or anything else
+ * that would rely on a stable page's memory cgroup.
+ *
+ * Note that folio_memcg_lock is a memcg lock, not a page lock,
+ * to save space. As soon as we switch page's memory cgroup to a
+ * new memcg that isn't locked, the above state can change
+ * concurrently again. Make sure we're truly done with it.
+ */
+ smp_mb();
+
+ css_get(&to->css);
+ css_put(&from->css);
+
+ folio->memcg_data = (unsigned long)to;
+
+ __folio_memcg_unlock(from);
+
+ ret = 0;
+ nid = folio_nid(folio);
+
+ local_irq_disable();
+ mem_cgroup_charge_statistics(to, nr_pages);
+ memcg_check_events(to, nid);
+ mem_cgroup_charge_statistics(from, -nr_pages);
+ memcg_check_events(from, nid);
+ local_irq_enable();
+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)
+ *
+ * Context: Called with pte lock held.
+ * Return:
+ * * MC_TARGET_NONE - If the pte is not a target for move charge.
+ * * 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 taken (Caller should release it).
+ * * 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.
+ * * MC_TARGET_DEVICE - Like MC_TARGET_PAGE but page is device memory and
+ * thus not on the lru. For now such page is charged like a regular page
+ * would be as it is just special memory taking the place of a regular page.
+ * See Documentations/vm/hmm.txt and include/linux/hmm.h
+ */
+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 (pte_none_mostly(ptent))
+ /*
+ * PTE markers should be treated as a none pte here, separated
+ * from other swap handling below.
+ */
+ page = mc_handle_file_pte(vma, addr, ptent);
+ else if (is_swap_pte(ptent))
+ page = mc_handle_swap_pte(vma, ptent, &ent);
+
+ if (target && page) {
+ if (!trylock_page(page)) {
+ put_page(page);
+ return ret;
+ }
+ /*
+ * page_mapped() must be stable during the move. This
+ * pte is locked, so if it's present, the page cannot
+ * become unmapped. If it isn't, we have only partial
+ * control over the mapped state: the page lock will
+ * prevent new faults against pagecache and swapcache,
+ * so an unmapped page cannot become mapped. However,
+ * if the page is already mapped elsewhere, it can
+ * unmap, and there is nothing we can do about it.
+ * Alas, skip moving the page in this case.
+ */
+ if (!pte_present(ptent) && page_mapped(page)) {
+ unlock_page(page);
+ put_page(page);
+ return ret;
+ }
+ }
+
+ if (!page && !ent.val)
+ return ret;
+ if (page) {
+ /*
+ * Do only loose check w/o serialization.
+ * mem_cgroup_move_account() checks the page is valid or
+ * not under LRU exclusion.
+ */
+ if (page_memcg(page) == mc.from) {
+ ret = MC_TARGET_PAGE;
+ if (is_device_private_page(page) ||
+ is_device_coherent_page(page))
+ ret = MC_TARGET_DEVICE;
+ if (target)
+ target->page = page;
+ }
+ if (!ret || !target) {
+ if (target)
+ unlock_page(page);
+ put_page(page);
+ }
+ }
+ /*
+ * There is a swap entry and a page doesn't exist or isn't charged.
+ * But we cannot move a tail-page in a THP.
+ */
+ if (ent.val && !ret && (!page || !PageTransCompound(page)) &&
+ mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) {
+ ret = MC_TARGET_SWAP;
+ if (target)
+ target->ent = ent;
+ }
+ return ret;
+}
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+/*
+ * We don't consider PMD mapped swapping or file mapped pages because THP does
+ * not support them for now.
+ * Caller should make sure that pmd_trans_huge(pmd) is true.
+ */
+static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
+ unsigned long addr, pmd_t pmd, union mc_target *target)
+{
+ struct page *page = NULL;
+ enum mc_target_type ret = MC_TARGET_NONE;
+
+ if (unlikely(is_swap_pmd(pmd))) {
+ VM_BUG_ON(thp_migration_supported() &&
+ !is_pmd_migration_entry(pmd));
+ return ret;
+ }
+ page = pmd_page(pmd);
+ VM_BUG_ON_PAGE(!page || !PageHead(page), page);
+ if (!(mc.flags & MOVE_ANON))
+ return ret;
+ if (page_memcg(page) == mc.from) {
+ ret = MC_TARGET_PAGE;
+ if (target) {
+ get_page(page);
+ if (!trylock_page(page)) {
+ put_page(page);
+ return MC_TARGET_NONE;
+ }
+ target->page = page;
+ }
+ }
+ return ret;
+}
+#else
+static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
+ unsigned long addr, pmd_t pmd, union mc_target *target)
+{
+ return MC_TARGET_NONE;
+}
+#endif
+
+static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
+ unsigned long addr, unsigned long end,
+ struct mm_walk *walk)
+{
+ struct vm_area_struct *vma = walk->vma;
+ pte_t *pte;
+ spinlock_t *ptl;
+
+ ptl = pmd_trans_huge_lock(pmd, vma);
+ if (ptl) {
+ /*
+ * Note their can not be MC_TARGET_DEVICE for now as we do not
+ * support transparent huge page with MEMORY_DEVICE_PRIVATE but
+ * this might change.
+ */
+ if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
+ mc.precharge += HPAGE_PMD_NR;
+ spin_unlock(ptl);
+ return 0;
+ }
+
+ pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
+ if (!pte)
+ return 0;
+ for (; addr != end; pte++, addr += PAGE_SIZE)
+ if (get_mctgt_type(vma, addr, ptep_get(pte), NULL))
+ mc.precharge++; /* increment precharge temporarily */
+ pte_unmap_unlock(pte - 1, ptl);
+ cond_resched();
+
+ return 0;
+}
+
+static const struct mm_walk_ops precharge_walk_ops = {
+ .pmd_entry = mem_cgroup_count_precharge_pte_range,
+ .walk_lock = PGWALK_RDLOCK,
+};
+
+static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
+{
+ unsigned long precharge;
+
+ mmap_read_lock(mm);
+ walk_page_range(mm, 0, ULONG_MAX, &precharge_walk_ops, NULL);
+ mmap_read_unlock(mm);
+
+ precharge = mc.precharge;
+ mc.precharge = 0;
+
+ return precharge;
+}
+
+static int mem_cgroup_precharge_mc(struct mm_struct *mm)
+{
+ unsigned long precharge = mem_cgroup_count_precharge(mm);
+
+ VM_BUG_ON(mc.moving_task);
+ mc.moving_task = current;
+ return mem_cgroup_do_precharge(precharge);
+}
+
+/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
+static void __mem_cgroup_clear_mc(void)
+{
+ struct mem_cgroup *from = mc.from;
+ struct mem_cgroup *to = mc.to;
+
+ /* we must uncharge all the leftover precharges from mc.to */
+ if (mc.precharge) {
+ cancel_charge(mc.to, mc.precharge);
+ mc.precharge = 0;
+ }
+ /*
+ * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
+ * we must uncharge here.
+ */
+ if (mc.moved_charge) {
+ cancel_charge(mc.from, mc.moved_charge);
+ mc.moved_charge = 0;
+ }
+ /* we must fixup refcnts and charges */
+ if (mc.moved_swap) {
+ /* uncharge swap account from the old cgroup */
+ if (!mem_cgroup_is_root(mc.from))
+ page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
+
+ mem_cgroup_id_put_many(mc.from, mc.moved_swap);
+
+ /*
+ * we charged both to->memory and to->memsw, so we
+ * should uncharge to->memory.
+ */
+ if (!mem_cgroup_is_root(mc.to))
+ page_counter_uncharge(&mc.to->memory, mc.moved_swap);
+
+ mc.moved_swap = 0;
+ }
+ memcg_oom_recover(from);
+ memcg_oom_recover(to);
+ wake_up_all(&mc.waitq);
+}
+
+static void mem_cgroup_clear_mc(void)
+{
+ struct mm_struct *mm = mc.mm;
+
+ /*
+ * we must clear moving_task before waking up waiters at the end of
+ * task migration.
+ */
+ mc.moving_task = NULL;
+ __mem_cgroup_clear_mc();
+ spin_lock(&mc.lock);
+ mc.from = NULL;
+ mc.to = NULL;
+ mc.mm = NULL;
+ spin_unlock(&mc.lock);
+
+ mmput(mm);
+}
+
+static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
+{
+ struct cgroup_subsys_state *css;
+ struct mem_cgroup *memcg = NULL; /* unneeded init to make gcc happy */
+ struct mem_cgroup *from;
+ struct task_struct *leader, *p;
+ struct mm_struct *mm;
+ unsigned long move_flags;
+ int ret = 0;
+
+ /* charge immigration isn't supported on the default hierarchy */
+ if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
+ return 0;
+
+ /*
+ * Multi-process migrations only happen on the default hierarchy
+ * where charge immigration is not used. Perform charge
+ * immigration if @tset contains a leader and whine if there are
+ * multiple.
+ */
+ p = NULL;
+ cgroup_taskset_for_each_leader(leader, css, tset) {
+ WARN_ON_ONCE(p);
+ p = leader;
+ memcg = mem_cgroup_from_css(css);
+ }
+ if (!p)
+ return 0;
+
+ /*
+ * We are now committed 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);
+ }
+ unlock_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;
+ }
+ unlock_page(page);
+ put_page(page);
+ }
+ spin_unlock(ptl);
+ return 0;
+ }
+
+retry:
+ pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
+ if (!pte)
+ return 0;
+ for (; addr != end; addr += PAGE_SIZE) {
+ pte_t ptent = ptep_get(pte++);
+ bool device = false;
+ swp_entry_t ent;
+
+ if (!mc.precharge)
+ break;
+
+ switch (get_mctgt_type(vma, addr, ptent, &target)) {
+ case MC_TARGET_DEVICE:
+ device = true;
+ fallthrough;
+ case MC_TARGET_PAGE:
+ page = target.page;
+ /*
+ * We can have a part of the split pmd here. Moving it
+ * can be done but it would be too convoluted so simply
+ * ignore such a partial THP and keep it in original
+ * memcg. There should be somebody mapping the head.
+ */
+ if (PageTransCompound(page))
+ goto put;
+ if (!device && !isolate_lru_page(page))
+ goto put;
+ if (!mem_cgroup_move_account(page, false,
+ mc.from, mc.to)) {
+ mc.precharge--;
+ /* we uncharge from mc.from later. */
+ mc.moved_charge++;
+ }
+ if (!device)
+ putback_lru_page(page);
+put: /* get_mctgt_type() gets & locks the page */
+ unlock_page(page);
+ put_page(page);
+ break;
+ case MC_TARGET_SWAP:
+ ent = target.ent;
+ if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
+ mc.precharge--;
+ mem_cgroup_id_get_many(mc.to, 1);
+ /* we fixup other refcnts and charges later. */
+ mc.moved_swap++;
+ }
+ break;
+ default:
+ break;
+ }
+ }
+ pte_unmap_unlock(pte - 1, ptl);
+ cond_resched();
+
+ if (addr != end) {
+ /*
+ * We have consumed all precharges we got in can_attach().
+ * We try charge one by one, but don't do any additional
+ * charges to mc.to if we have failed in charge once in attach()
+ * phase.
+ */
+ ret = mem_cgroup_do_precharge(1);
+ if (!ret)
+ goto retry;
+ }
+
+ return ret;
+}
+
+static const struct mm_walk_ops charge_walk_ops = {
+ .pmd_entry = mem_cgroup_move_charge_pte_range,
+ .walk_lock = PGWALK_RDLOCK,
+};
+
+static void mem_cgroup_move_charge(void)
+{
+ lru_add_drain_all();
+ /*
+ * Signal folio_memcg_lock() to take the memcg's move_lock
+ * while we're moving its pages to another memcg. Then wait
+ * for already started RCU-only updates to finish.
+ */
+ atomic_inc(&mc.from->moving_account);
+ synchronize_rcu();
+retry:
+ if (unlikely(!mmap_read_trylock(mc.mm))) {
+ /*
+ * Someone who are holding the mmap_lock might be waiting in
+ * waitq. So we cancel all extra charges, wake up all waiters,
+ * and retry. Because we cancel precharges, we might not be able
+ * to move enough charges, but moving charge is a best-effort
+ * feature anyway, so it wouldn't be a big problem.
+ */
+ __mem_cgroup_clear_mc();
+ cond_resched();
+ goto retry;
+ }
+ /*
+ * When we have consumed all precharges and failed in doing
+ * additional charge, the page walk just aborts.
+ */
+ walk_page_range(mc.mm, 0, ULONG_MAX, &charge_walk_ops, NULL);
+ mmap_read_unlock(mc.mm);
+ atomic_dec(&mc.from->moving_account);
+}
+
+static void mem_cgroup_move_task(void)
+{
+ if (mc.to) {
+ mem_cgroup_move_charge();
+ mem_cgroup_clear_mc();
+ }
+}
+#else /* !CONFIG_MMU */
+static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
+{
+ return 0;
+}
+static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
+{
+}
+static void mem_cgroup_move_task(void)
+{
+}
+#endif
+
+#ifdef CONFIG_LRU_GEN
+static void mem_cgroup_attach(struct cgroup_taskset *tset)
+{
+ struct task_struct *task;
+ struct cgroup_subsys_state *css;
+
+ /* find the first leader if there is any */
+ cgroup_taskset_for_each_leader(task, css, tset)
+ break;
+
+ if (!task)
+ return;
+
+ task_lock(task);
+ if (task->mm && READ_ONCE(task->mm->owner) == task)
+ lru_gen_migrate_mm(task->mm);
+ task_unlock(task);
+}
+#else
+static void mem_cgroup_attach(struct cgroup_taskset *tset)
+{
+}
+#endif /* CONFIG_LRU_GEN */
+
+static int seq_puts_memcg_tunable(struct seq_file *m, unsigned long value)
+{
+ if (value == PAGE_COUNTER_MAX)
+ seq_puts(m, "max\n");
+ else
+ seq_printf(m, "%llu\n", (u64)value * PAGE_SIZE);
+
+ return 0;
+}
+
+static u64 memory_current_read(struct cgroup_subsys_state *css,
+ struct cftype *cft)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+
+ return (u64)page_counter_read(&memcg->memory) * PAGE_SIZE;
+}
+
+static u64 memory_peak_read(struct cgroup_subsys_state *css,
+ struct cftype *cft)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+
+ return (u64)memcg->memory.watermark * PAGE_SIZE;
+}
+
+static int memory_min_show(struct seq_file *m, void *v)
+{
+ return seq_puts_memcg_tunable(m,
+ READ_ONCE(mem_cgroup_from_seq(m)->memory.min));
+}
+
+static ssize_t memory_min_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+ unsigned long min;
+ int err;
+
+ buf = strstrip(buf);
+ err = page_counter_memparse(buf, "max", &min);
+ if (err)
+ return err;
+
+ page_counter_set_min(&memcg->memory, min);
+
+ return nbytes;
+}
+
+static int memory_low_show(struct seq_file *m, void *v)
+{
+ return seq_puts_memcg_tunable(m,
+ READ_ONCE(mem_cgroup_from_seq(m)->memory.low));
+}
+
+static ssize_t memory_low_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+ unsigned long low;
+ int err;
+
+ buf = strstrip(buf);
+ err = page_counter_memparse(buf, "max", &low);
+ if (err)
+ return err;
+
+ page_counter_set_low(&memcg->memory, low);
+
+ return nbytes;
+}
+
+static int memory_high_show(struct seq_file *m, void *v)
+{
+ return seq_puts_memcg_tunable(m,
+ READ_ONCE(mem_cgroup_from_seq(m)->memory.high));
+}
+
+static ssize_t memory_high_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+ unsigned int nr_retries = MAX_RECLAIM_RETRIES;
+ bool drained = false;
+ unsigned long high;
+ int err;
+
+ buf = strstrip(buf);
+ err = page_counter_memparse(buf, "max", &high);
+ if (err)
+ return err;
+
+ page_counter_set_high(&memcg->memory, high);
+
+ for (;;) {
+ unsigned long nr_pages = page_counter_read(&memcg->memory);
+ unsigned long reclaimed;
+
+ if (nr_pages <= high)
+ break;
+
+ if (signal_pending(current))
+ break;
+
+ if (!drained) {
+ drain_all_stock(memcg);
+ drained = true;
+ continue;
+ }
+
+ reclaimed = try_to_free_mem_cgroup_pages(memcg, nr_pages - high,
+ GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP);
+
+ if (!reclaimed && !nr_retries--)
+ break;
+ }
+
+ memcg_wb_domain_size_changed(memcg);
+ return nbytes;
+}
+
+static int memory_max_show(struct seq_file *m, void *v)
+{
+ return seq_puts_memcg_tunable(m,
+ READ_ONCE(mem_cgroup_from_seq(m)->memory.max));
+}
+
+static ssize_t memory_max_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+ unsigned int nr_reclaims = MAX_RECLAIM_RETRIES;
+ bool drained = false;
+ unsigned long max;
+ int err;
+
+ buf = strstrip(buf);
+ err = page_counter_memparse(buf, "max", &max);
+ if (err)
+ return err;
+
+ xchg(&memcg->memory.max, max);
+
+ for (;;) {
+ unsigned long nr_pages = page_counter_read(&memcg->memory);
+
+ if (nr_pages <= max)
+ break;
+
+ if (signal_pending(current))
+ break;
+
+ if (!drained) {
+ drain_all_stock(memcg);
+ drained = true;
+ continue;
+ }
+
+ if (nr_reclaims) {
+ if (!try_to_free_mem_cgroup_pages(memcg, nr_pages - max,
+ GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP))
+ nr_reclaims--;
+ continue;
+ }
+
+ memcg_memory_event(memcg, MEMCG_OOM);
+ if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0))
+ break;
+ }
+
+ memcg_wb_domain_size_changed(memcg);
+ return nbytes;
+}
+
+static void __memory_events_show(struct seq_file *m, atomic_long_t *events)
+{
+ seq_printf(m, "low %lu\n", atomic_long_read(&events[MEMCG_LOW]));
+ seq_printf(m, "high %lu\n", atomic_long_read(&events[MEMCG_HIGH]));
+ seq_printf(m, "max %lu\n", atomic_long_read(&events[MEMCG_MAX]));
+ seq_printf(m, "oom %lu\n", atomic_long_read(&events[MEMCG_OOM]));
+ seq_printf(m, "oom_kill %lu\n",
+ atomic_long_read(&events[MEMCG_OOM_KILL]));
+ seq_printf(m, "oom_group_kill %lu\n",
+ atomic_long_read(&events[MEMCG_OOM_GROUP_KILL]));
+}
+
+static int memory_events_show(struct seq_file *m, void *v)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
+
+ __memory_events_show(m, memcg->memory_events);
+ return 0;
+}
+
+static int memory_events_local_show(struct seq_file *m, void *v)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
+
+ __memory_events_show(m, memcg->memory_events_local);
+ return 0;
+}
+
+static int memory_stat_show(struct seq_file *m, void *v)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
+ char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ struct seq_buf s;
+
+ if (!buf)
+ return -ENOMEM;
+ seq_buf_init(&s, buf, PAGE_SIZE);
+ memory_stat_format(memcg, &s);
+ seq_puts(m, buf);
+ kfree(buf);
+ return 0;
+}
+
+#ifdef CONFIG_NUMA
+static inline unsigned long lruvec_page_state_output(struct lruvec *lruvec,
+ int item)
+{
+ return lruvec_page_state(lruvec, item) * memcg_page_state_unit(item);
+}
+
+static int memory_numa_stat_show(struct seq_file *m, void *v)
+{
+ int i;
+ struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
+
+ mem_cgroup_flush_stats();
+
+ for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
+ int nid;
+
+ if (memory_stats[i].idx >= NR_VM_NODE_STAT_ITEMS)
+ continue;
+
+ seq_printf(m, "%s", memory_stats[i].name);
+ for_each_node_state(nid, N_MEMORY) {
+ u64 size;
+ struct lruvec *lruvec;
+
+ lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
+ size = lruvec_page_state_output(lruvec,
+ memory_stats[i].idx);
+ seq_printf(m, " N%d=%llu", nid, size);
+ }
+ seq_putc(m, '\n');
+ }
+
+ return 0;
+}
+#endif
+
+static int memory_oom_group_show(struct seq_file *m, void *v)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
+
+ seq_printf(m, "%d\n", READ_ONCE(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;
+
+ WRITE_ONCE(memcg->oom_group, oom_group);
+
+ return nbytes;
+}
+
+static ssize_t memory_reclaim(struct kernfs_open_file *of, char *buf,
+ size_t nbytes, loff_t off)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+ unsigned int nr_retries = MAX_RECLAIM_RETRIES;
+ unsigned long nr_to_reclaim, nr_reclaimed = 0;
+ unsigned int reclaim_options;
+ int err;
+
+ buf = strstrip(buf);
+ err = page_counter_memparse(buf, "", &nr_to_reclaim);
+ if (err)
+ return err;
+
+ reclaim_options = MEMCG_RECLAIM_MAY_SWAP | MEMCG_RECLAIM_PROACTIVE;
+ while (nr_reclaimed < nr_to_reclaim) {
+ unsigned long reclaimed;
+
+ if (signal_pending(current))
+ return -EINTR;
+
+ /*
+ * This is the final attempt, drain percpu lru caches in the
+ * hope of introducing more evictable pages for
+ * try_to_free_mem_cgroup_pages().
+ */
+ if (!nr_retries)
+ lru_add_drain_all();
+
+ reclaimed = try_to_free_mem_cgroup_pages(memcg,
+ min(nr_to_reclaim - nr_reclaimed, SWAP_CLUSTER_MAX),
+ GFP_KERNEL, reclaim_options);
+
+ if (!reclaimed && !nr_retries--)
+ return -EAGAIN;
+
+ nr_reclaimed += reclaimed;
+ }
+
+ return nbytes;
+}
+
+static struct cftype memory_files[] = {
+ {
+ .name = "current",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .read_u64 = memory_current_read,
+ },
+ {
+ .name = "peak",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .read_u64 = memory_peak_read,
+ },
+ {
+ .name = "min",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = memory_min_show,
+ .write = memory_min_write,
+ },
+ {
+ .name = "low",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = memory_low_show,
+ .write = memory_low_write,
+ },
+ {
+ .name = "high",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = memory_high_show,
+ .write = memory_high_write,
+ },
+ {
+ .name = "max",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = memory_max_show,
+ .write = memory_max_write,
+ },
+ {
+ .name = "events",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .file_offset = offsetof(struct mem_cgroup, events_file),
+ .seq_show = memory_events_show,
+ },
+ {
+ .name = "events.local",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .file_offset = offsetof(struct mem_cgroup, events_local_file),
+ .seq_show = memory_events_local_show,
+ },
+ {
+ .name = "stat",
+ .seq_show = memory_stat_show,
+ },
+#ifdef CONFIG_NUMA
+ {
+ .name = "numa_stat",
+ .seq_show = memory_numa_stat_show,
+ },
+#endif
+ {
+ .name = "oom.group",
+ .flags = CFTYPE_NOT_ON_ROOT | CFTYPE_NS_DELEGATABLE,
+ .seq_show = memory_oom_group_show,
+ .write = memory_oom_group_write,
+ },
+ {
+ .name = "reclaim",
+ .flags = CFTYPE_NS_DELEGATABLE,
+ .write = memory_reclaim,
+ },
+ { } /* terminate */
+};
+
+struct cgroup_subsys memory_cgrp_subsys = {
+ .css_alloc = mem_cgroup_css_alloc,
+ .css_online = mem_cgroup_css_online,
+ .css_offline = mem_cgroup_css_offline,
+ .css_released = mem_cgroup_css_released,
+ .css_free = mem_cgroup_css_free,
+ .css_reset = mem_cgroup_css_reset,
+ .css_rstat_flush = mem_cgroup_css_rstat_flush,
+ .can_attach = mem_cgroup_can_attach,
+ .attach = mem_cgroup_attach,
+ .cancel_attach = mem_cgroup_cancel_attach,
+ .post_attach = mem_cgroup_move_task,
+ .dfl_cftypes = memory_files,
+ .legacy_cftypes = mem_cgroup_legacy_files,
+ .early_init = 0,
+};
+
+/*
+ * This function calculates an individual cgroup's effective
+ * protection which is derived from its own memory.min/low, its
+ * parent's and siblings' settings, as well as the actual memory
+ * distribution in the tree.
+ *
+ * The following rules apply to the effective protection values:
+ *
+ * 1. At the first level of reclaim, effective protection is equal to
+ * the declared protection in memory.min and memory.low.
+ *
+ * 2. To enable safe delegation of the protection configuration, at
+ * subsequent levels the effective protection is capped to the
+ * parent's effective protection.
+ *
+ * 3. To make complex and dynamic subtrees easier to configure, the
+ * user is allowed to overcommit the declared protection at a given
+ * level. If that is the case, the parent's effective protection is
+ * distributed to the children in proportion to how much protection
+ * they have declared and how much of it they are utilizing.
+ *
+ * This makes distribution proportional, but also work-conserving:
+ * if one cgroup claims much more protection than it uses memory,
+ * the unused remainder is available to its siblings.
+ *
+ * 4. Conversely, when the declared protection is undercommitted at a
+ * given level, the distribution of the larger parental protection
+ * budget is NOT proportional. A cgroup's protection from a sibling
+ * is capped to its own memory.min/low setting.
+ *
+ * 5. However, to allow protecting recursive subtrees from each other
+ * without having to declare each individual cgroup's fixed share
+ * of the ancestor's claim to protection, any unutilized -
+ * "floating" - protection from up the tree is distributed in
+ * proportion to each cgroup's *usage*. This makes the protection
+ * neutral wrt sibling cgroups and lets them compete freely over
+ * the shared parental protection budget, but it protects the
+ * subtree as a whole from neighboring subtrees.
+ *
+ * Note that 4. and 5. are not in conflict: 4. is about protecting
+ * against immediate siblings whereas 5. is about protecting against
+ * neighboring subtrees.
+ */
+static unsigned long effective_protection(unsigned long usage,
+ unsigned long parent_usage,
+ unsigned long setting,
+ unsigned long parent_effective,
+ unsigned long siblings_protected)
+{
+ unsigned long protected;
+ unsigned long ep;
+
+ protected = min(usage, setting);
+ /*
+ * If all cgroups at this level combined claim and use more
+ * protection than what the parent affords them, distribute
+ * shares in proportion to utilization.
+ *
+ * We are using actual utilization rather than the statically
+ * claimed protection in order to be work-conserving: claimed
+ * but unused protection is available to siblings that would
+ * otherwise get a smaller chunk than what they claimed.
+ */
+ if (siblings_protected > parent_effective)
+ return protected * parent_effective / siblings_protected;
+
+ /*
+ * Ok, utilized protection of all children is within what the
+ * parent affords them, so we know whatever this child claims
+ * and utilizes is effectively protected.
+ *
+ * If there is unprotected usage beyond this value, reclaim
+ * will apply pressure in proportion to that amount.
+ *
+ * If there is unutilized protection, the cgroup will be fully
+ * shielded from reclaim, but we do return a smaller value for
+ * protection than what the group could enjoy in theory. This
+ * is okay. With the overcommit distribution above, effective
+ * protection is always dependent on how memory is actually
+ * consumed among the siblings anyway.
+ */
+ ep = protected;
+
+ /*
+ * If the children aren't claiming (all of) the protection
+ * afforded to them by the parent, distribute the remainder in
+ * proportion to the (unprotected) memory of each cgroup. That
+ * way, cgroups that aren't explicitly prioritized wrt each
+ * other compete freely over the allowance, but they are
+ * collectively protected from neighboring trees.
+ *
+ * We're using unprotected memory for the weight so that if
+ * some cgroups DO claim explicit protection, we don't protect
+ * the same bytes twice.
+ *
+ * Check both usage and parent_usage against the respective
+ * protected values. One should imply the other, but they
+ * aren't read atomically - make sure the division is sane.
+ */
+ if (!(cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_RECURSIVE_PROT))
+ return ep;
+ if (parent_effective > siblings_protected &&
+ parent_usage > siblings_protected &&
+ usage > protected) {
+ unsigned long unclaimed;
+
+ unclaimed = parent_effective - siblings_protected;
+ unclaimed *= usage - protected;
+ unclaimed /= parent_usage - siblings_protected;
+
+ ep += unclaimed;
+ }
+
+ return ep;
+}
+
+/**
+ * mem_cgroup_calculate_protection - check if memory consumption is in the normal range
+ * @root: the top ancestor of the sub-tree being checked
+ * @memcg: the memory cgroup to check
+ *
+ * WARNING: This function is not stateless! It can only be used as part
+ * of a top-down tree iteration, not for isolated queries.
+ */
+void mem_cgroup_calculate_protection(struct mem_cgroup *root,
+ struct mem_cgroup *memcg)
+{
+ unsigned long usage, parent_usage;
+ struct mem_cgroup *parent;
+
+ if (mem_cgroup_disabled())
+ return;
+
+ if (!root)
+ root = root_mem_cgroup;
+
+ /*
+ * Effective values of the reclaim targets are ignored so they
+ * can be stale. Have a look at mem_cgroup_protection for more
+ * details.
+ * TODO: calculation should be more robust so that we do not need
+ * that special casing.
+ */
+ if (memcg == root)
+ return;
+
+ usage = page_counter_read(&memcg->memory);
+ if (!usage)
+ return;
+
+ parent = parent_mem_cgroup(memcg);
+
+ if (parent == root) {
+ memcg->memory.emin = READ_ONCE(memcg->memory.min);
+ memcg->memory.elow = READ_ONCE(memcg->memory.low);
+ return;
+ }
+
+ parent_usage = page_counter_read(&parent->memory);
+
+ WRITE_ONCE(memcg->memory.emin, effective_protection(usage, parent_usage,
+ READ_ONCE(memcg->memory.min),
+ READ_ONCE(parent->memory.emin),
+ atomic_long_read(&parent->memory.children_min_usage)));
+
+ WRITE_ONCE(memcg->memory.elow, effective_protection(usage, parent_usage,
+ READ_ONCE(memcg->memory.low),
+ READ_ONCE(parent->memory.elow),
+ atomic_long_read(&parent->memory.children_low_usage)));
+}
+
+static int charge_memcg(struct folio *folio, struct mem_cgroup *memcg,
+ gfp_t gfp)
+{
+ long nr_pages = folio_nr_pages(folio);
+ int ret;
+
+ ret = try_charge(memcg, gfp, nr_pages);
+ if (ret)
+ goto out;
+
+ css_get(&memcg->css);
+ commit_charge(folio, memcg);
+
+ local_irq_disable();
+ mem_cgroup_charge_statistics(memcg, nr_pages);
+ memcg_check_events(memcg, folio_nid(folio));
+ local_irq_enable();
+out:
+ return ret;
+}
+
+int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp)
+{
+ struct mem_cgroup *memcg;
+ int ret;
+
+ memcg = get_mem_cgroup_from_mm(mm);
+ ret = charge_memcg(folio, memcg, gfp);
+ css_put(&memcg->css);
+
+ return ret;
+}
+
+/**
+ * mem_cgroup_swapin_charge_folio - Charge a newly allocated folio for swapin.
+ * @folio: folio to charge.
+ * @mm: mm context of the victim
+ * @gfp: reclaim mode
+ * @entry: swap entry for which the folio is allocated
+ *
+ * This function charges a folio allocated for swapin. Please call this before
+ * adding the folio to the swapcache.
+ *
+ * Returns 0 on success. Otherwise, an error code is returned.
+ */
+int mem_cgroup_swapin_charge_folio(struct folio *folio, struct mm_struct *mm,
+ gfp_t gfp, swp_entry_t entry)
+{
+ struct mem_cgroup *memcg;
+ unsigned short id;
+ int ret;
+
+ if (mem_cgroup_disabled())
+ return 0;
+
+ id = lookup_swap_cgroup_id(entry);
+ rcu_read_lock();
+ memcg = mem_cgroup_from_id(id);
+ if (!memcg || !css_tryget_online(&memcg->css))
+ memcg = get_mem_cgroup_from_mm(mm);
+ rcu_read_unlock();
+
+ ret = charge_memcg(folio, memcg, gfp);
+
+ css_put(&memcg->css);
+ return ret;
+}
+
+/*
+ * mem_cgroup_swapin_uncharge_swap - uncharge swap slot
+ * @entry: swap entry for which the page is charged
+ *
+ * Call this function after successfully adding the charged page to swapcache.
+ *
+ * Note: This function assumes the page for which swap slot is being uncharged
+ * is order 0 page.
+ */
+void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry)
+{
+ /*
+ * Cgroup1's unified memory+swap counter has been charged with the
+ * new swapcache page, finish the transfer by uncharging the swap
+ * slot. The swap slot would also get uncharged when it dies, but
+ * it can stick around indefinitely and we'd count the page twice
+ * the entire time.
+ *
+ * Cgroup2 has separate resource counters for memory and swap,
+ * so this is a non-issue here. Memory and swap charge lifetimes
+ * correspond 1:1 to page and swap slot lifetimes: we charge the
+ * page to memory here, and uncharge swap when the slot is freed.
+ */
+ if (!mem_cgroup_disabled() && do_memsw_account()) {
+ /*
+ * 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, 1);
+ }
+}
+
+struct uncharge_gather {
+ struct mem_cgroup *memcg;
+ unsigned long nr_memory;
+ unsigned long pgpgout;
+ unsigned long nr_kmem;
+ int nid;
+};
+
+static inline void uncharge_gather_clear(struct uncharge_gather *ug)
+{
+ memset(ug, 0, sizeof(*ug));
+}
+
+static void uncharge_batch(const struct uncharge_gather *ug)
+{
+ unsigned long flags;
+
+ if (ug->nr_memory) {
+ page_counter_uncharge(&ug->memcg->memory, ug->nr_memory);
+ if (do_memsw_account())
+ page_counter_uncharge(&ug->memcg->memsw, ug->nr_memory);
+ if (ug->nr_kmem)
+ memcg_account_kmem(ug->memcg, -ug->nr_kmem);
+ memcg_oom_recover(ug->memcg);
+ }
+
+ local_irq_save(flags);
+ __count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
+ __this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, ug->nr_memory);
+ memcg_check_events(ug->memcg, ug->nid);
+ local_irq_restore(flags);
+
+ /* drop reference from uncharge_folio */
+ css_put(&ug->memcg->css);
+}
+
+static void uncharge_folio(struct folio *folio, struct uncharge_gather *ug)
+{
+ long nr_pages;
+ struct mem_cgroup *memcg;
+ struct obj_cgroup *objcg;
+
+ VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
+
+ /*
+ * Nobody should be changing or seriously looking at
+ * folio memcg or objcg at this point, we have fully
+ * exclusive access to the folio.
+ */
+ if (folio_memcg_kmem(folio)) {
+ objcg = __folio_objcg(folio);
+ /*
+ * This get matches the put at the end of the function and
+ * kmem pages do not hold memcg references anymore.
+ */
+ memcg = get_mem_cgroup_from_objcg(objcg);
+ } else {
+ memcg = __folio_memcg(folio);
+ }
+
+ if (!memcg)
+ return;
+
+ if (ug->memcg != memcg) {
+ if (ug->memcg) {
+ uncharge_batch(ug);
+ uncharge_gather_clear(ug);
+ }
+ ug->memcg = memcg;
+ ug->nid = folio_nid(folio);
+
+ /* pairs with css_put in uncharge_batch */
+ css_get(&memcg->css);
+ }
+
+ nr_pages = folio_nr_pages(folio);
+
+ if (folio_memcg_kmem(folio)) {
+ ug->nr_memory += nr_pages;
+ ug->nr_kmem += nr_pages;
+
+ folio->memcg_data = 0;
+ obj_cgroup_put(objcg);
+ } else {
+ /* LRU pages aren't accounted at the root level */
+ if (!mem_cgroup_is_root(memcg))
+ ug->nr_memory += nr_pages;
+ ug->pgpgout++;
+
+ folio->memcg_data = 0;
+ }
+
+ css_put(&memcg->css);
+}
+
+void __mem_cgroup_uncharge(struct folio *folio)
+{
+ struct uncharge_gather ug;
+
+ /* Don't touch folio->lru of any random page, pre-check: */
+ if (!folio_memcg(folio))
+ return;
+
+ uncharge_gather_clear(&ug);
+ uncharge_folio(folio, &ug);
+ uncharge_batch(&ug);
+}
+
+/**
+ * __mem_cgroup_uncharge_list - uncharge a list of page
+ * @page_list: list of pages to uncharge
+ *
+ * Uncharge a list of pages previously charged with
+ * __mem_cgroup_charge().
+ */
+void __mem_cgroup_uncharge_list(struct list_head *page_list)
+{
+ struct uncharge_gather ug;
+ struct folio *folio;
+
+ uncharge_gather_clear(&ug);
+ list_for_each_entry(folio, page_list, lru)
+ uncharge_folio(folio, &ug);
+ if (ug.memcg)
+ uncharge_batch(&ug);
+}
+
+/**
+ * mem_cgroup_migrate - Charge a folio's replacement.
+ * @old: Currently circulating folio.
+ * @new: Replacement folio.
+ *
+ * Charge @new as a replacement folio for @old. @old will
+ * be uncharged upon free.
+ *
+ * Both folios must be locked, @new->mapping must be set up.
+ */
+void mem_cgroup_migrate(struct folio *old, struct folio *new)
+{
+ struct mem_cgroup *memcg;
+ long nr_pages = folio_nr_pages(new);
+ unsigned long flags;
+
+ VM_BUG_ON_FOLIO(!folio_test_locked(old), old);
+ VM_BUG_ON_FOLIO(!folio_test_locked(new), new);
+ VM_BUG_ON_FOLIO(folio_test_anon(old) != folio_test_anon(new), new);
+ VM_BUG_ON_FOLIO(folio_nr_pages(old) != nr_pages, new);
+
+ if (mem_cgroup_disabled())
+ return;
+
+ /* Page cache replacement: new folio already charged? */
+ if (folio_memcg(new))
+ return;
+
+ memcg = folio_memcg(old);
+ VM_WARN_ON_ONCE_FOLIO(!memcg, old);
+ if (!memcg)
+ return;
+
+ /* Force-charge the new page. The old one will be freed soon */
+ if (!mem_cgroup_is_root(memcg)) {
+ page_counter_charge(&memcg->memory, nr_pages);
+ if (do_memsw_account())
+ page_counter_charge(&memcg->memsw, nr_pages);
+ }
+
+ css_get(&memcg->css);
+ commit_charge(new, memcg);
+
+ local_irq_save(flags);
+ mem_cgroup_charge_statistics(memcg, nr_pages);
+ memcg_check_events(memcg, folio_nid(new));
+ local_irq_restore(flags);
+}
+
+DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key);
+EXPORT_SYMBOL(memcg_sockets_enabled_key);
+
+void mem_cgroup_sk_alloc(struct sock *sk)
+{
+ struct mem_cgroup *memcg;
+
+ if (!mem_cgroup_sockets_enabled)
+ return;
+
+ /* Do not associate the sock with unrelated interrupted task's memcg. */
+ if (!in_task())
+ return;
+
+ rcu_read_lock();
+ memcg = mem_cgroup_from_task(current);
+ if (mem_cgroup_is_root(memcg))
+ goto out;
+ if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg->tcpmem_active)
+ goto out;
+ if (css_tryget(&memcg->css))
+ sk->sk_memcg = memcg;
+out:
+ rcu_read_unlock();
+}
+
+void mem_cgroup_sk_free(struct sock *sk)
+{
+ if (sk->sk_memcg)
+ css_put(&sk->sk_memcg->css);
+}
+
+/**
+ * mem_cgroup_charge_skmem - charge socket memory
+ * @memcg: memcg to charge
+ * @nr_pages: number of pages to charge
+ * @gfp_mask: reclaim mode
+ *
+ * Charges @nr_pages to @memcg. Returns %true if the charge fit within
+ * @memcg's configured limit, %false if it doesn't.
+ */
+bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages,
+ gfp_t gfp_mask)
+{
+ 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;
+ }
+ memcg->tcpmem_pressure = 1;
+ if (gfp_mask & __GFP_NOFAIL) {
+ page_counter_charge(&memcg->tcpmem, nr_pages);
+ return true;
+ }
+ return false;
+ }
+
+ if (try_charge(memcg, gfp_mask, nr_pages) == 0) {
+ mod_memcg_state(memcg, MEMCG_SOCK, nr_pages);
+ return true;
+ }
+
+ 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;
+ if (!strcmp(token, "nobpf"))
+ cgroup_memory_nobpf = true;
+ }
+ return 1;
+}
+__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;
+
+ /*
+ * Currently s32 type (can refer to struct batched_lruvec_stat) is
+ * used for per-memcg-per-cpu caching of per-node statistics. In order
+ * to work fine, we should make sure that the overfill threshold can't
+ * exceed S32_MAX / PAGE_SIZE.
+ */
+ BUILD_BUG_ON(MEMCG_CHARGE_BATCH > S32_MAX / PAGE_SIZE);
+
+ 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);
+
+ 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_SWAP
+static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
+{
+ while (!refcount_inc_not_zero(&memcg->id.ref)) {
+ /*
+ * The root cgroup cannot be destroyed, so it's refcount must
+ * always be >= 1.
+ */
+ if (WARN_ON_ONCE(mem_cgroup_is_root(memcg))) {
+ 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
+ * @folio: folio whose memsw charge to transfer
+ * @entry: swap entry to move the charge to
+ *
+ * Transfer the memsw charge of @folio to @entry.
+ */
+void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry)
+{
+ struct mem_cgroup *memcg, *swap_memcg;
+ unsigned int nr_entries;
+ unsigned short oldid;
+
+ VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
+ VM_BUG_ON_FOLIO(folio_ref_count(folio), folio);
+
+ if (mem_cgroup_disabled())
+ return;
+
+ if (!do_memsw_account())
+ return;
+
+ memcg = folio_memcg(folio);
+
+ VM_WARN_ON_ONCE_FOLIO(!memcg, folio);
+ 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 = folio_nr_pages(folio);
+ /* 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_FOLIO(oldid, folio);
+ mod_memcg_state(swap_memcg, MEMCG_SWAP, nr_entries);
+
+ folio->memcg_data = 0;
+
+ 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.
+ */
+ memcg_stats_lock();
+ mem_cgroup_charge_statistics(memcg, -nr_entries);
+ memcg_stats_unlock();
+ memcg_check_events(memcg, folio_nid(folio));
+
+ css_put(&memcg->css);
+}
+
+/**
+ * __mem_cgroup_try_charge_swap - try charging swap space for a folio
+ * @folio: folio being added to swap
+ * @entry: swap entry to charge
+ *
+ * Try to charge @folio's memcg for the swap space at @entry.
+ *
+ * Returns 0 on success, -ENOMEM on failure.
+ */
+int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry)
+{
+ unsigned int nr_pages = folio_nr_pages(folio);
+ struct page_counter *counter;
+ struct mem_cgroup *memcg;
+ unsigned short oldid;
+
+ if (do_memsw_account())
+ return 0;
+
+ memcg = folio_memcg(folio);
+
+ VM_WARN_ON_ONCE_FOLIO(!memcg, folio);
+ if (!memcg)
+ return 0;
+
+ if (!entry.val) {
+ memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
+ return 0;
+ }
+
+ 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_FOLIO(oldid, folio);
+ mod_memcg_state(memcg, MEMCG_SWAP, nr_pages);
+
+ return 0;
+}
+
+/**
+ * __mem_cgroup_uncharge_swap - uncharge swap space
+ * @entry: swap entry to uncharge
+ * @nr_pages: the amount of swap space to uncharge
+ */
+void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
+{
+ struct mem_cgroup *memcg;
+ unsigned short id;
+
+ id = swap_cgroup_record(entry, 0, nr_pages);
+ rcu_read_lock();
+ memcg = mem_cgroup_from_id(id);
+ if (memcg) {
+ if (!mem_cgroup_is_root(memcg)) {
+ if (do_memsw_account())
+ page_counter_uncharge(&memcg->memsw, nr_pages);
+ else
+ page_counter_uncharge(&memcg->swap, nr_pages);
+ }
+ mod_memcg_state(memcg, MEMCG_SWAP, -nr_pages);
+ mem_cgroup_id_put_many(memcg, nr_pages);
+ }
+ rcu_read_unlock();
+}
+
+long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
+{
+ long nr_swap_pages = get_nr_swap_pages();
+
+ if (mem_cgroup_disabled() || do_memsw_account())
+ return nr_swap_pages;
+ for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg))
+ nr_swap_pages = min_t(long, nr_swap_pages,
+ READ_ONCE(memcg->swap.max) -
+ page_counter_read(&memcg->swap));
+ return nr_swap_pages;
+}
+
+bool mem_cgroup_swap_full(struct folio *folio)
+{
+ struct mem_cgroup *memcg;
+
+ VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
+
+ if (vm_swap_full())
+ return true;
+ if (do_memsw_account())
+ return false;
+
+ memcg = folio_memcg(folio);
+ if (!memcg)
+ return false;
+
+ for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) {
+ unsigned long usage = page_counter_read(&memcg->swap);
+
+ if (usage * 2 >= READ_ONCE(memcg->swap.high) ||
+ usage * 2 >= READ_ONCE(memcg->swap.max))
+ return true;
+ }
+
+ return false;
+}
+
+static int __init setup_swap_account(char *s)
+{
+ pr_warn_once("The swapaccount= commandline option is deprecated. "
+ "Please report your usecase to linux-mm@kvack.org if you "
+ "depend on this functionality.\n");
+ return 1;
+}
+__setup("swapaccount=", setup_swap_account);
+
+static u64 swap_current_read(struct cgroup_subsys_state *css,
+ struct cftype *cft)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+
+ return (u64)page_counter_read(&memcg->swap) * PAGE_SIZE;
+}
+
+static u64 swap_peak_read(struct cgroup_subsys_state *css,
+ struct cftype *cft)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+
+ return (u64)memcg->swap.watermark * PAGE_SIZE;
+}
+
+static int swap_high_show(struct seq_file *m, void *v)
+{
+ return seq_puts_memcg_tunable(m,
+ READ_ONCE(mem_cgroup_from_seq(m)->swap.high));
+}
+
+static ssize_t swap_high_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+ unsigned long high;
+ int err;
+
+ buf = strstrip(buf);
+ err = page_counter_memparse(buf, "max", &high);
+ if (err)
+ return err;
+
+ page_counter_set_high(&memcg->swap, high);
+
+ return nbytes;
+}
+
+static int swap_max_show(struct seq_file *m, void *v)
+{
+ return seq_puts_memcg_tunable(m,
+ READ_ONCE(mem_cgroup_from_seq(m)->swap.max));
+}
+
+static ssize_t swap_max_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+ unsigned long max;
+ int err;
+
+ buf = strstrip(buf);
+ err = page_counter_memparse(buf, "max", &max);
+ if (err)
+ return err;
+
+ xchg(&memcg->swap.max, max);
+
+ return nbytes;
+}
+
+static int swap_events_show(struct seq_file *m, void *v)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
+
+ seq_printf(m, "high %lu\n",
+ atomic_long_read(&memcg->memory_events[MEMCG_SWAP_HIGH]));
+ seq_printf(m, "max %lu\n",
+ atomic_long_read(&memcg->memory_events[MEMCG_SWAP_MAX]));
+ seq_printf(m, "fail %lu\n",
+ atomic_long_read(&memcg->memory_events[MEMCG_SWAP_FAIL]));
+
+ return 0;
+}
+
+static struct cftype swap_files[] = {
+ {
+ .name = "swap.current",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .read_u64 = swap_current_read,
+ },
+ {
+ .name = "swap.high",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = swap_high_show,
+ .write = swap_high_write,
+ },
+ {
+ .name = "swap.max",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = swap_max_show,
+ .write = swap_max_write,
+ },
+ {
+ .name = "swap.peak",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .read_u64 = swap_peak_read,
+ },
+ {
+ .name = "swap.events",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .file_offset = offsetof(struct mem_cgroup, swap_events_file),
+ .seq_show = swap_events_show,
+ },
+ { } /* terminate */
+};
+
+static struct cftype memsw_files[] = {
+ {
+ .name = "memsw.usage_in_bytes",
+ .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
+ .read_u64 = mem_cgroup_read_u64,
+ },
+ {
+ .name = "memsw.max_usage_in_bytes",
+ .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
+ .write = mem_cgroup_reset,
+ .read_u64 = mem_cgroup_read_u64,
+ },
+ {
+ .name = "memsw.limit_in_bytes",
+ .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
+ .write = mem_cgroup_write,
+ .read_u64 = mem_cgroup_read_u64,
+ },
+ {
+ .name = "memsw.failcnt",
+ .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
+ .write = mem_cgroup_reset,
+ .read_u64 = mem_cgroup_read_u64,
+ },
+ { }, /* terminate */
+};
+
+#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
+/**
+ * obj_cgroup_may_zswap - check if this cgroup can zswap
+ * @objcg: the object cgroup
+ *
+ * Check if the hierarchical zswap limit has been reached.
+ *
+ * This doesn't check for specific headroom, and it is not atomic
+ * either. But with zswap, the size of the allocation is only known
+ * once compression has occured, and this optimistic pre-check avoids
+ * spending cycles on compression when there is already no room left
+ * or zswap is disabled altogether somewhere in the hierarchy.
+ */
+bool obj_cgroup_may_zswap(struct obj_cgroup *objcg)
+{
+ struct mem_cgroup *memcg, *original_memcg;
+ bool ret = true;
+
+ if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
+ return true;
+
+ original_memcg = get_mem_cgroup_from_objcg(objcg);
+ for (memcg = original_memcg; !mem_cgroup_is_root(memcg);
+ memcg = parent_mem_cgroup(memcg)) {
+ unsigned long max = READ_ONCE(memcg->zswap_max);
+ unsigned long pages;
+
+ if (max == PAGE_COUNTER_MAX)
+ continue;
+ if (max == 0) {
+ ret = false;
+ break;
+ }
+
+ cgroup_rstat_flush(memcg->css.cgroup);
+ pages = memcg_page_state(memcg, MEMCG_ZSWAP_B) / PAGE_SIZE;
+ if (pages < max)
+ continue;
+ ret = false;
+ break;
+ }
+ mem_cgroup_put(original_memcg);
+ return ret;
+}
+
+/**
+ * obj_cgroup_charge_zswap - charge compression backend memory
+ * @objcg: the object cgroup
+ * @size: size of compressed object
+ *
+ * This forces the charge after obj_cgroup_may_zswap() allowed
+ * compression and storage in zwap for this cgroup to go ahead.
+ */
+void obj_cgroup_charge_zswap(struct obj_cgroup *objcg, size_t size)
+{
+ struct mem_cgroup *memcg;
+
+ if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
+ return;
+
+ VM_WARN_ON_ONCE(!(current->flags & PF_MEMALLOC));
+
+ /* PF_MEMALLOC context, charging must succeed */
+ if (obj_cgroup_charge(objcg, GFP_KERNEL, size))
+ VM_WARN_ON_ONCE(1);
+
+ rcu_read_lock();
+ memcg = obj_cgroup_memcg(objcg);
+ mod_memcg_state(memcg, MEMCG_ZSWAP_B, size);
+ mod_memcg_state(memcg, MEMCG_ZSWAPPED, 1);
+ rcu_read_unlock();
+}
+
+/**
+ * obj_cgroup_uncharge_zswap - uncharge compression backend memory
+ * @objcg: the object cgroup
+ * @size: size of compressed object
+ *
+ * Uncharges zswap memory on page in.
+ */
+void obj_cgroup_uncharge_zswap(struct obj_cgroup *objcg, size_t size)
+{
+ struct mem_cgroup *memcg;
+
+ if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
+ return;
+
+ obj_cgroup_uncharge(objcg, size);
+
+ rcu_read_lock();
+ memcg = obj_cgroup_memcg(objcg);
+ mod_memcg_state(memcg, MEMCG_ZSWAP_B, -size);
+ mod_memcg_state(memcg, MEMCG_ZSWAPPED, -1);
+ rcu_read_unlock();
+}
+
+static u64 zswap_current_read(struct cgroup_subsys_state *css,
+ struct cftype *cft)
+{
+ cgroup_rstat_flush(css->cgroup);
+ return memcg_page_state(mem_cgroup_from_css(css), MEMCG_ZSWAP_B);
+}
+
+static int zswap_max_show(struct seq_file *m, void *v)
+{
+ return seq_puts_memcg_tunable(m,
+ READ_ONCE(mem_cgroup_from_seq(m)->zswap_max));
+}
+
+static ssize_t zswap_max_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+ unsigned long max;
+ int err;
+
+ buf = strstrip(buf);
+ err = page_counter_memparse(buf, "max", &max);
+ if (err)
+ return err;
+
+ xchg(&memcg->zswap_max, max);
+
+ return nbytes;
+}
+
+static struct cftype zswap_files[] = {
+ {
+ .name = "zswap.current",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .read_u64 = zswap_current_read,
+ },
+ {
+ .name = "zswap.max",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = zswap_max_show,
+ .write = zswap_max_write,
+ },
+ { } /* terminate */
+};
+#endif /* CONFIG_MEMCG_KMEM && CONFIG_ZSWAP */
+
+static int __init mem_cgroup_swap_init(void)
+{
+ if (mem_cgroup_disabled())
+ return 0;
+
+ WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, swap_files));
+ WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, memsw_files));
+#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
+ WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, zswap_files));
+#endif
+ return 0;
+}
+subsys_initcall(mem_cgroup_swap_init);
+
+#endif /* CONFIG_SWAP */