Linux 6.9-rc1

[linux-2.6-microblaze.git] / include / linux / memcontrol.h

/* SPDX-License-Identifier: GPL-2.0-or-later */
/* memcontrol.h - 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>
 */

#ifndef _LINUX_MEMCONTROL_H
#define _LINUX_MEMCONTROL_H
#include <linux/cgroup.h>
#include <linux/vm_event_item.h>
#include <linux/hardirq.h>
#include <linux/jump_label.h>
#include <linux/kernel.h>
#include <linux/page_counter.h>
#include <linux/vmpressure.h>
#include <linux/eventfd.h>
#include <linux/mm.h>
#include <linux/vmstat.h>
#include <linux/writeback.h>
#include <linux/page-flags.h>
#include <linux/shrinker.h>

struct mem_cgroup;
struct obj_cgroup;
struct page;
struct mm_struct;
struct kmem_cache;

/* Cgroup-specific page state, on top of universal node page state */
enum memcg_stat_item {
        MEMCG_SWAP = NR_VM_NODE_STAT_ITEMS,
        MEMCG_SOCK,
        MEMCG_PERCPU_B,
        MEMCG_VMALLOC,
        MEMCG_KMEM,
        MEMCG_ZSWAP_B,
        MEMCG_ZSWAPPED,
        MEMCG_NR_STAT,
};

enum memcg_memory_event {
        MEMCG_LOW,
        MEMCG_HIGH,
        MEMCG_MAX,
        MEMCG_OOM,
        MEMCG_OOM_KILL,
        MEMCG_OOM_GROUP_KILL,
        MEMCG_SWAP_HIGH,
        MEMCG_SWAP_MAX,
        MEMCG_SWAP_FAIL,
        MEMCG_NR_MEMORY_EVENTS,
};

struct mem_cgroup_reclaim_cookie {
        pg_data_t *pgdat;
        unsigned int generation;
};

#ifdef CONFIG_MEMCG

#define MEM_CGROUP_ID_SHIFT     16

struct mem_cgroup_id {
        int id;
        refcount_t ref;
};

/*
 * Per memcg event counter is incremented at every pagein/pageout. With THP,
 * it will be incremented by the number of pages. This counter is used
 * to trigger some periodic events. This is straightforward and better
 * than using jiffies etc. to handle periodic memcg event.
 */
enum mem_cgroup_events_target {
        MEM_CGROUP_TARGET_THRESH,
        MEM_CGROUP_TARGET_SOFTLIMIT,
        MEM_CGROUP_NTARGETS,
};

struct memcg_vmstats_percpu;
struct memcg_vmstats;

struct mem_cgroup_reclaim_iter {
        struct mem_cgroup *position;
        /* scan generation, increased every round-trip */
        unsigned int generation;
};

struct lruvec_stats_percpu {
        /* Local (CPU and cgroup) state */
        long state[NR_VM_NODE_STAT_ITEMS];

        /* Delta calculation for lockless upward propagation */
        long state_prev[NR_VM_NODE_STAT_ITEMS];
};

struct lruvec_stats {
        /* Aggregated (CPU and subtree) state */
        long state[NR_VM_NODE_STAT_ITEMS];

        /* Non-hierarchical (CPU aggregated) state */
        long state_local[NR_VM_NODE_STAT_ITEMS];

        /* Pending child counts during tree propagation */
        long state_pending[NR_VM_NODE_STAT_ITEMS];
};

/*
 * per-node information in memory controller.
 */
struct mem_cgroup_per_node {
        struct lruvec           lruvec;

        struct lruvec_stats_percpu __percpu     *lruvec_stats_percpu;
        struct lruvec_stats                     lruvec_stats;

        unsigned long           lru_zone_size[MAX_NR_ZONES][NR_LRU_LISTS];

        struct mem_cgroup_reclaim_iter  iter;

        struct shrinker_info __rcu      *shrinker_info;

        struct rb_node          tree_node;      /* RB tree node */
        unsigned long           usage_in_excess;/* Set to the value by which */
                                                /* the soft limit is exceeded*/
        bool                    on_tree;
        struct mem_cgroup       *memcg;         /* Back pointer, we cannot */
                                                /* use container_of        */
};

struct mem_cgroup_threshold {
        struct eventfd_ctx *eventfd;
        unsigned long threshold;
};

/* For threshold */
struct mem_cgroup_threshold_ary {
        /* An array index points to threshold just below or equal to usage. */
        int current_threshold;
        /* Size of entries[] */
        unsigned int size;
        /* Array of thresholds */
        struct mem_cgroup_threshold entries[] __counted_by(size);
};

struct mem_cgroup_thresholds {
        /* Primary thresholds array */
        struct mem_cgroup_threshold_ary *primary;
        /*
         * Spare threshold array.
         * This is needed to make mem_cgroup_unregister_event() "never fail".
         * It must be able to store at least primary->size - 1 entries.
         */
        struct mem_cgroup_threshold_ary *spare;
};

/*
 * Remember four most recent foreign writebacks with dirty pages in this
 * cgroup.  Inode sharing is expected to be uncommon and, even if we miss
 * one in a given round, we're likely to catch it later if it keeps
 * foreign-dirtying, so a fairly low count should be enough.
 *
 * See mem_cgroup_track_foreign_dirty_slowpath() for details.
 */
#define MEMCG_CGWB_FRN_CNT      4

struct memcg_cgwb_frn {
        u64 bdi_id;                     /* bdi->id of the foreign inode */
        int memcg_id;                   /* memcg->css.id of foreign inode */
        u64 at;                         /* jiffies_64 at the time of dirtying */
        struct wb_completion done;      /* tracks in-flight foreign writebacks */
};

/*
 * Bucket for arbitrarily byte-sized objects charged to a memory
 * cgroup. The bucket can be reparented in one piece when the cgroup
 * is destroyed, without having to round up the individual references
 * of all live memory objects in the wild.
 */
struct obj_cgroup {
        struct percpu_ref refcnt;
        struct mem_cgroup *memcg;
        atomic_t nr_charged_bytes;
        union {
                struct list_head list; /* protected by objcg_lock */
                struct rcu_head rcu;
        };
};

/*
 * The memory controller data structure. The memory controller controls both
 * page cache and RSS per cgroup. We would eventually like to provide
 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
 * to help the administrator determine what knobs to tune.
 */
struct mem_cgroup {
        struct cgroup_subsys_state css;

        /* Private memcg ID. Used to ID objects that outlive the cgroup */
        struct mem_cgroup_id id;

        /* Accounted resources */
        struct page_counter memory;             /* Both v1 & v2 */

        union {
                struct page_counter swap;       /* v2 only */
                struct page_counter memsw;      /* v1 only */
        };

        /* Legacy consumer-oriented counters */
        struct page_counter kmem;               /* v1 only */
        struct page_counter tcpmem;             /* v1 only */

        /* Range enforcement for interrupt charges */
        struct work_struct high_work;

#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
        unsigned long zswap_max;

        /*
         * Prevent pages from this memcg from being written back from zswap to
         * swap, and from being swapped out on zswap store failures.
         */
        bool zswap_writeback;
#endif

        unsigned long soft_limit;

        /* vmpressure notifications */
        struct vmpressure vmpressure;

        /*
         * Should the OOM killer kill all belonging tasks, had it kill one?
         */
        bool oom_group;

        /* protected by memcg_oom_lock */
        bool            oom_lock;
        int             under_oom;

        int     swappiness;
        /* OOM-Killer disable */
        int             oom_kill_disable;

        /* memory.events and memory.events.local */
        struct cgroup_file events_file;
        struct cgroup_file events_local_file;

        /* handle for "memory.swap.events" */
        struct cgroup_file swap_events_file;

        /* protect arrays of thresholds */
        struct mutex thresholds_lock;

        /* thresholds for memory usage. RCU-protected */
        struct mem_cgroup_thresholds thresholds;

        /* thresholds for mem+swap usage. RCU-protected */
        struct mem_cgroup_thresholds memsw_thresholds;

        /* For oom notifier event fd */
        struct list_head oom_notify;

        /*
         * Should we move charges of a task when a task is moved into this
         * mem_cgroup ? And what type of charges should we move ?
         */
        unsigned long move_charge_at_immigrate;
        /* taken only while moving_account > 0 */
        spinlock_t              move_lock;
        unsigned long           move_lock_flags;

        CACHELINE_PADDING(_pad1_);

        /* memory.stat */
        struct memcg_vmstats    *vmstats;

        /* memory.events */
        atomic_long_t           memory_events[MEMCG_NR_MEMORY_EVENTS];
        atomic_long_t           memory_events_local[MEMCG_NR_MEMORY_EVENTS];

        /*
         * Hint of reclaim pressure for socket memroy management. Note
         * that this indicator should NOT be used in legacy cgroup mode
         * where socket memory is accounted/charged separately.
         */
        unsigned long           socket_pressure;

        /* Legacy tcp memory accounting */
        bool                    tcpmem_active;
        int                     tcpmem_pressure;

#ifdef CONFIG_MEMCG_KMEM
        int kmemcg_id;
        /*
         * memcg->objcg is wiped out as a part of the objcg repaprenting
         * process. memcg->orig_objcg preserves a pointer (and a reference)
         * to the original objcg until the end of live of memcg.
         */
        struct obj_cgroup __rcu *objcg;
        struct obj_cgroup       *orig_objcg;
        /* list of inherited objcgs, protected by objcg_lock */
        struct list_head objcg_list;
#endif

        CACHELINE_PADDING(_pad2_);

        /*
         * set > 0 if pages under this cgroup are moving to other cgroup.
         */
        atomic_t                moving_account;
        struct task_struct      *move_lock_task;

        struct memcg_vmstats_percpu __percpu *vmstats_percpu;

#ifdef CONFIG_CGROUP_WRITEBACK
        struct list_head cgwb_list;
        struct wb_domain cgwb_domain;
        struct memcg_cgwb_frn cgwb_frn[MEMCG_CGWB_FRN_CNT];
#endif

        /* List of events which userspace want to receive */
        struct list_head event_list;
        spinlock_t event_list_lock;

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
        struct deferred_split deferred_split_queue;
#endif

#ifdef CONFIG_LRU_GEN_WALKS_MMU
        /* per-memcg mm_struct list */
        struct lru_gen_mm_list mm_list;
#endif

        struct mem_cgroup_per_node *nodeinfo[];
};

/*
 * size of first charge trial.
 * TODO: maybe necessary to use big numbers in big irons or dynamic based of the
 * workload.
 */
#define MEMCG_CHARGE_BATCH 64U

extern struct mem_cgroup *root_mem_cgroup;

enum page_memcg_data_flags {
        /* page->memcg_data is a pointer to an objcgs vector */
        MEMCG_DATA_OBJCGS = (1UL << 0),
        /* page has been accounted as a non-slab kernel page */
        MEMCG_DATA_KMEM = (1UL << 1),
        /* the next bit after the last actual flag */
        __NR_MEMCG_DATA_FLAGS  = (1UL << 2),
};

#define MEMCG_DATA_FLAGS_MASK (__NR_MEMCG_DATA_FLAGS - 1)

static inline bool folio_memcg_kmem(struct folio *folio);

/*
 * After the initialization objcg->memcg is always pointing at
 * a valid memcg, but can be atomically swapped to the parent memcg.
 *
 * The caller must ensure that the returned memcg won't be released:
 * e.g. acquire the rcu_read_lock or css_set_lock.
 */
static inline struct mem_cgroup *obj_cgroup_memcg(struct obj_cgroup *objcg)
{
        return READ_ONCE(objcg->memcg);
}

/*
 * __folio_memcg - Get the memory cgroup associated with a non-kmem folio
 * @folio: Pointer to the folio.
 *
 * Returns a pointer to the memory cgroup associated with the folio,
 * or NULL. This function assumes that the folio is known to have a
 * proper memory cgroup pointer. It's not safe to call this function
 * against some type of folios, e.g. slab folios or ex-slab folios or
 * kmem folios.
 */
static inline struct mem_cgroup *__folio_memcg(struct folio *folio)
{
        unsigned long memcg_data = folio->memcg_data;

        VM_BUG_ON_FOLIO(folio_test_slab(folio), folio);
        VM_BUG_ON_FOLIO(memcg_data & MEMCG_DATA_OBJCGS, folio);
        VM_BUG_ON_FOLIO(memcg_data & MEMCG_DATA_KMEM, folio);

        return (struct mem_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
}

/*
 * __folio_objcg - get the object cgroup associated with a kmem folio.
 * @folio: Pointer to the folio.
 *
 * Returns a pointer to the object cgroup associated with the folio,
 * or NULL. This function assumes that the folio is known to have a
 * proper object cgroup pointer. It's not safe to call this function
 * against some type of folios, e.g. slab folios or ex-slab folios or
 * LRU folios.
 */
static inline struct obj_cgroup *__folio_objcg(struct folio *folio)
{
        unsigned long memcg_data = folio->memcg_data;

        VM_BUG_ON_FOLIO(folio_test_slab(folio), folio);
        VM_BUG_ON_FOLIO(memcg_data & MEMCG_DATA_OBJCGS, folio);
        VM_BUG_ON_FOLIO(!(memcg_data & MEMCG_DATA_KMEM), folio);

        return (struct obj_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
}

/*
 * folio_memcg - Get the memory cgroup associated with a folio.
 * @folio: Pointer to the folio.
 *
 * Returns a pointer to the memory cgroup associated with the folio,
 * or NULL. This function assumes that the folio is known to have a
 * proper memory cgroup pointer. It's not safe to call this function
 * against some type of folios, e.g. slab folios or ex-slab folios.
 *
 * For a non-kmem folio any of the following ensures folio and memcg binding
 * stability:
 *
 * - the folio lock
 * - LRU isolation
 * - folio_memcg_lock()
 * - exclusive reference
 * - mem_cgroup_trylock_pages()
 *
 * For a kmem folio a caller should hold an rcu read lock to protect memcg
 * associated with a kmem folio from being released.
 */
static inline struct mem_cgroup *folio_memcg(struct folio *folio)
{
        if (folio_memcg_kmem(folio))
                return obj_cgroup_memcg(__folio_objcg(folio));
        return __folio_memcg(folio);
}

static inline struct mem_cgroup *page_memcg(struct page *page)
{
        return folio_memcg(page_folio(page));
}

/**
 * folio_memcg_rcu - Locklessly get the memory cgroup associated with a folio.
 * @folio: Pointer to the folio.
 *
 * This function assumes that the folio is known to have a
 * proper memory cgroup pointer. It's not safe to call this function
 * against some type of folios, e.g. slab folios or ex-slab folios.
 *
 * Return: A pointer to the memory cgroup associated with the folio,
 * or NULL.
 */
static inline struct mem_cgroup *folio_memcg_rcu(struct folio *folio)
{
        unsigned long memcg_data = READ_ONCE(folio->memcg_data);

        VM_BUG_ON_FOLIO(folio_test_slab(folio), folio);
        WARN_ON_ONCE(!rcu_read_lock_held());

        if (memcg_data & MEMCG_DATA_KMEM) {
                struct obj_cgroup *objcg;

                objcg = (void *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
                return obj_cgroup_memcg(objcg);
        }

        return (struct mem_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
}

/*
 * folio_memcg_check - Get the memory cgroup associated with a folio.
 * @folio: Pointer to the folio.
 *
 * Returns a pointer to the memory cgroup associated with the folio,
 * or NULL. This function unlike folio_memcg() can take any folio
 * as an argument. It has to be used in cases when it's not known if a folio
 * has an associated memory cgroup pointer or an object cgroups vector or
 * an object cgroup.
 *
 * For a non-kmem folio any of the following ensures folio and memcg binding
 * stability:
 *
 * - the folio lock
 * - LRU isolation
 * - lock_folio_memcg()
 * - exclusive reference
 * - mem_cgroup_trylock_pages()
 *
 * For a kmem folio a caller should hold an rcu read lock to protect memcg
 * associated with a kmem folio from being released.
 */
static inline struct mem_cgroup *folio_memcg_check(struct folio *folio)
{
        /*
         * Because folio->memcg_data might be changed asynchronously
         * for slabs, READ_ONCE() should be used here.
         */
        unsigned long memcg_data = READ_ONCE(folio->memcg_data);

        if (memcg_data & MEMCG_DATA_OBJCGS)
                return NULL;

        if (memcg_data & MEMCG_DATA_KMEM) {
                struct obj_cgroup *objcg;

                objcg = (void *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
                return obj_cgroup_memcg(objcg);
        }

        return (struct mem_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
}

static inline struct mem_cgroup *page_memcg_check(struct page *page)
{
        if (PageTail(page))
                return NULL;
        return folio_memcg_check((struct folio *)page);
}

static inline struct mem_cgroup *get_mem_cgroup_from_objcg(struct obj_cgroup *objcg)
{
        struct mem_cgroup *memcg;

        rcu_read_lock();
retry:
        memcg = obj_cgroup_memcg(objcg);
        if (unlikely(!css_tryget(&memcg->css)))
                goto retry;
        rcu_read_unlock();

        return memcg;
}

#ifdef CONFIG_MEMCG_KMEM
/*
 * folio_memcg_kmem - Check if the folio has the memcg_kmem flag set.
 * @folio: Pointer to the folio.
 *
 * Checks if the folio has MemcgKmem flag set. The caller must ensure
 * that the folio has an associated memory cgroup. It's not safe to call
 * this function against some types of folios, e.g. slab folios.
 */
static inline bool folio_memcg_kmem(struct folio *folio)
{
        VM_BUG_ON_PGFLAGS(PageTail(&folio->page), &folio->page);
        VM_BUG_ON_FOLIO(folio->memcg_data & MEMCG_DATA_OBJCGS, folio);
        return folio->memcg_data & MEMCG_DATA_KMEM;
}


#else
static inline bool folio_memcg_kmem(struct folio *folio)
{
        return false;
}

#endif

static inline bool PageMemcgKmem(struct page *page)
{
        return folio_memcg_kmem(page_folio(page));
}

static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
{
        return (memcg == root_mem_cgroup);
}

static inline bool mem_cgroup_disabled(void)
{
        return !cgroup_subsys_enabled(memory_cgrp_subsys);
}

static inline void mem_cgroup_protection(struct mem_cgroup *root,
                                         struct mem_cgroup *memcg,
                                         unsigned long *min,
                                         unsigned long *low)
{
        *min = *low = 0;

        if (mem_cgroup_disabled())
                return;

        /*
         * There is no reclaim protection applied to a targeted reclaim.
         * We are special casing this specific case here because
         * mem_cgroup_calculate_protection is not robust enough to keep
         * the protection invariant for calculated effective values for
         * parallel reclaimers with different reclaim target. This is
         * especially a problem for tail memcgs (as they have pages on LRU)
         * which would want to have effective values 0 for targeted reclaim
         * but a different value for external reclaim.
         *
         * Example
         * Let's have global and A's reclaim in parallel:
         *  |
         *  A (low=2G, usage = 3G, max = 3G, children_low_usage = 1.5G)
         *  |\
         *  | C (low = 1G, usage = 2.5G)
         *  B (low = 1G, usage = 0.5G)
         *
         * For the global reclaim
         * A.elow = A.low
         * B.elow = min(B.usage, B.low) because children_low_usage <= A.elow
         * C.elow = min(C.usage, C.low)
         *
         * With the effective values resetting we have A reclaim
         * A.elow = 0
         * B.elow = B.low
         * C.elow = C.low
         *
         * If the global reclaim races with A's reclaim then
         * B.elow = C.elow = 0 because children_low_usage > A.elow)
         * is possible and reclaiming B would be violating the protection.
         *
         */
        if (root == memcg)
                return;

        *min = READ_ONCE(memcg->memory.emin);
        *low = READ_ONCE(memcg->memory.elow);
}

void mem_cgroup_calculate_protection(struct mem_cgroup *root,
                                     struct mem_cgroup *memcg);

static inline bool mem_cgroup_unprotected(struct mem_cgroup *target,
                                          struct mem_cgroup *memcg)
{
        /*
         * The root memcg doesn't account charges, and doesn't support
         * protection. The target memcg's protection is ignored, see
         * mem_cgroup_calculate_protection() and mem_cgroup_protection()
         */
        return mem_cgroup_disabled() || mem_cgroup_is_root(memcg) ||
                memcg == target;
}

static inline bool mem_cgroup_below_low(struct mem_cgroup *target,
                                        struct mem_cgroup *memcg)
{
        if (mem_cgroup_unprotected(target, memcg))
                return false;

        return READ_ONCE(memcg->memory.elow) >=
                page_counter_read(&memcg->memory);
}

static inline bool mem_cgroup_below_min(struct mem_cgroup *target,
                                        struct mem_cgroup *memcg)
{
        if (mem_cgroup_unprotected(target, memcg))
                return false;

        return READ_ONCE(memcg->memory.emin) >=
                page_counter_read(&memcg->memory);
}

void mem_cgroup_commit_charge(struct folio *folio, struct mem_cgroup *memcg);

int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp);

/**
 * mem_cgroup_charge - Charge a newly allocated folio to a cgroup.
 * @folio: Folio to charge.
 * @mm: mm context of the allocating task.
 * @gfp: Reclaim mode.
 *
 * Try to charge @folio to the memcg that @mm belongs to, reclaiming
 * pages according to @gfp if necessary.  If @mm is NULL, try to
 * charge to the active memcg.
 *
 * Do not use this for folios allocated for swapin.
 *
 * Return: 0 on success. Otherwise, an error code is returned.
 */
static inline int mem_cgroup_charge(struct folio *folio, struct mm_struct *mm,
                                    gfp_t gfp)
{
        if (mem_cgroup_disabled())
                return 0;
        return __mem_cgroup_charge(folio, mm, gfp);
}

int mem_cgroup_hugetlb_try_charge(struct mem_cgroup *memcg, gfp_t gfp,
                long nr_pages);

int mem_cgroup_swapin_charge_folio(struct folio *folio, struct mm_struct *mm,
                                  gfp_t gfp, swp_entry_t entry);
void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry);

void __mem_cgroup_uncharge(struct folio *folio);

/**
 * mem_cgroup_uncharge - Uncharge a folio.
 * @folio: Folio to uncharge.
 *
 * Uncharge a folio previously charged with mem_cgroup_charge().
 */
static inline void mem_cgroup_uncharge(struct folio *folio)
{
        if (mem_cgroup_disabled())
                return;
        __mem_cgroup_uncharge(folio);
}

void __mem_cgroup_uncharge_folios(struct folio_batch *folios);
static inline void mem_cgroup_uncharge_folios(struct folio_batch *folios)
{
        if (mem_cgroup_disabled())
                return;
        __mem_cgroup_uncharge_folios(folios);
}

void mem_cgroup_cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages);
void mem_cgroup_replace_folio(struct folio *old, struct folio *new);
void mem_cgroup_migrate(struct folio *old, struct folio *new);

/**
 * mem_cgroup_lruvec - get the lru list vector for a memcg & node
 * @memcg: memcg of the wanted lruvec
 * @pgdat: pglist_data
 *
 * Returns the lru list vector holding pages for a given @memcg &
 * @pgdat combination. This can be the node lruvec, if the memory
 * controller is disabled.
 */
static inline struct lruvec *mem_cgroup_lruvec(struct mem_cgroup *memcg,
                                               struct pglist_data *pgdat)
{
        struct mem_cgroup_per_node *mz;
        struct lruvec *lruvec;

        if (mem_cgroup_disabled()) {
                lruvec = &pgdat->__lruvec;
                goto out;
        }

        if (!memcg)
                memcg = root_mem_cgroup;

        mz = memcg->nodeinfo[pgdat->node_id];
        lruvec = &mz->lruvec;
out:
        /*
         * Since a node can be onlined after the mem_cgroup was created,
         * we have to be prepared to initialize lruvec->pgdat here;
         * and if offlined then reonlined, we need to reinitialize it.
         */
        if (unlikely(lruvec->pgdat != pgdat))
                lruvec->pgdat = pgdat;
        return lruvec;
}

/**
 * folio_lruvec - return lruvec for isolating/putting an LRU folio
 * @folio: Pointer to the folio.
 *
 * This function relies on folio->mem_cgroup being stable.
 */
static inline struct lruvec *folio_lruvec(struct folio *folio)
{
        struct mem_cgroup *memcg = folio_memcg(folio);

        VM_WARN_ON_ONCE_FOLIO(!memcg && !mem_cgroup_disabled(), folio);
        return mem_cgroup_lruvec(memcg, folio_pgdat(folio));
}

struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);

struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm);

struct mem_cgroup *get_mem_cgroup_from_current(void);

struct lruvec *folio_lruvec_lock(struct folio *folio);
struct lruvec *folio_lruvec_lock_irq(struct folio *folio);
struct lruvec *folio_lruvec_lock_irqsave(struct folio *folio,
                                                unsigned long *flags);

#ifdef CONFIG_DEBUG_VM
void lruvec_memcg_debug(struct lruvec *lruvec, struct folio *folio);
#else
static inline
void lruvec_memcg_debug(struct lruvec *lruvec, struct folio *folio)
{
}
#endif

static inline
struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css){
        return css ? container_of(css, struct mem_cgroup, css) : NULL;
}

static inline bool obj_cgroup_tryget(struct obj_cgroup *objcg)
{
        return percpu_ref_tryget(&objcg->refcnt);
}

static inline void obj_cgroup_get(struct obj_cgroup *objcg)
{
        percpu_ref_get(&objcg->refcnt);
}

static inline void obj_cgroup_get_many(struct obj_cgroup *objcg,
                                       unsigned long nr)
{
        percpu_ref_get_many(&objcg->refcnt, nr);
}

static inline void obj_cgroup_put(struct obj_cgroup *objcg)
{
        percpu_ref_put(&objcg->refcnt);
}

static inline bool mem_cgroup_tryget(struct mem_cgroup *memcg)
{
        return !memcg || css_tryget(&memcg->css);
}

static inline bool mem_cgroup_tryget_online(struct mem_cgroup *memcg)
{
        return !memcg || css_tryget_online(&memcg->css);
}

static inline void mem_cgroup_put(struct mem_cgroup *memcg)
{
        if (memcg)
                css_put(&memcg->css);
}

#define mem_cgroup_from_counter(counter, member)        \
        container_of(counter, struct mem_cgroup, member)

struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *,
                                   struct mem_cgroup *,
                                   struct mem_cgroup_reclaim_cookie *);
void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);
void mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
                           int (*)(struct task_struct *, void *), void *arg);

static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
{
        if (mem_cgroup_disabled())
                return 0;

        return memcg->id.id;
}
struct mem_cgroup *mem_cgroup_from_id(unsigned short id);

#ifdef CONFIG_SHRINKER_DEBUG
static inline unsigned long mem_cgroup_ino(struct mem_cgroup *memcg)
{
        return memcg ? cgroup_ino(memcg->css.cgroup) : 0;
}

struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino);
#endif

static inline struct mem_cgroup *mem_cgroup_from_seq(struct seq_file *m)
{
        return mem_cgroup_from_css(seq_css(m));
}

static inline struct mem_cgroup *lruvec_memcg(struct lruvec *lruvec)
{
        struct mem_cgroup_per_node *mz;

        if (mem_cgroup_disabled())
                return NULL;

        mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
        return mz->memcg;
}

/**
 * parent_mem_cgroup - find the accounting parent of a memcg
 * @memcg: memcg whose parent to find
 *
 * Returns the parent memcg, or NULL if this is the root.
 */
static inline struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
{
        return mem_cgroup_from_css(memcg->css.parent);
}

static inline bool mem_cgroup_is_descendant(struct mem_cgroup *memcg,
                              struct mem_cgroup *root)
{
        if (root == memcg)
                return true;
        return cgroup_is_descendant(memcg->css.cgroup, root->css.cgroup);
}

static inline bool mm_match_cgroup(struct mm_struct *mm,
                                   struct mem_cgroup *memcg)
{
        struct mem_cgroup *task_memcg;
        bool match = false;

        rcu_read_lock();
        task_memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
        if (task_memcg)
                match = mem_cgroup_is_descendant(task_memcg, memcg);
        rcu_read_unlock();
        return match;
}

struct cgroup_subsys_state *mem_cgroup_css_from_folio(struct folio *folio);
ino_t page_cgroup_ino(struct page *page);

static inline bool mem_cgroup_online(struct mem_cgroup *memcg)
{
        if (mem_cgroup_disabled())
                return true;
        return !!(memcg->css.flags & CSS_ONLINE);
}

void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
                int zid, int nr_pages);

static inline
unsigned long mem_cgroup_get_zone_lru_size(struct lruvec *lruvec,
                enum lru_list lru, int zone_idx)
{
        struct mem_cgroup_per_node *mz;

        mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
        return READ_ONCE(mz->lru_zone_size[zone_idx][lru]);
}

void mem_cgroup_handle_over_high(gfp_t gfp_mask);

unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg);

unsigned long mem_cgroup_size(struct mem_cgroup *memcg);

void mem_cgroup_print_oom_context(struct mem_cgroup *memcg,
                                struct task_struct *p);

void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg);

static inline void mem_cgroup_enter_user_fault(void)
{
        WARN_ON(current->in_user_fault);
        current->in_user_fault = 1;
}

static inline void mem_cgroup_exit_user_fault(void)
{
        WARN_ON(!current->in_user_fault);
        current->in_user_fault = 0;
}

static inline bool task_in_memcg_oom(struct task_struct *p)
{
        return p->memcg_in_oom;
}

bool mem_cgroup_oom_synchronize(bool wait);
struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim,
                                            struct mem_cgroup *oom_domain);
void mem_cgroup_print_oom_group(struct mem_cgroup *memcg);

void folio_memcg_lock(struct folio *folio);
void folio_memcg_unlock(struct folio *folio);

void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val);

/* try to stablize folio_memcg() for all the pages in a memcg */
static inline bool mem_cgroup_trylock_pages(struct mem_cgroup *memcg)
{
        rcu_read_lock();

        if (mem_cgroup_disabled() || !atomic_read(&memcg->moving_account))
                return true;

        rcu_read_unlock();
        return false;
}

static inline void mem_cgroup_unlock_pages(void)
{
        rcu_read_unlock();
}

/* idx can be of type enum memcg_stat_item or node_stat_item */
static inline void mod_memcg_state(struct mem_cgroup *memcg,
                                   int idx, int val)
{
        unsigned long flags;

        local_irq_save(flags);
        __mod_memcg_state(memcg, idx, val);
        local_irq_restore(flags);
}

static inline void mod_memcg_page_state(struct page *page,
                                        int idx, int val)
{
        struct mem_cgroup *memcg;

        if (mem_cgroup_disabled())
                return;

        rcu_read_lock();
        memcg = page_memcg(page);
        if (memcg)
                mod_memcg_state(memcg, idx, val);
        rcu_read_unlock();
}

unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx);

static inline unsigned long lruvec_page_state(struct lruvec *lruvec,
                                              enum node_stat_item idx)
{
        struct mem_cgroup_per_node *pn;
        long x;

        if (mem_cgroup_disabled())
                return node_page_state(lruvec_pgdat(lruvec), idx);

        pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
        x = READ_ONCE(pn->lruvec_stats.state[idx]);
#ifdef CONFIG_SMP
        if (x < 0)
                x = 0;
#endif
        return x;
}

static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec,
                                                    enum node_stat_item idx)
{
        struct mem_cgroup_per_node *pn;
        long x = 0;

        if (mem_cgroup_disabled())
                return node_page_state(lruvec_pgdat(lruvec), idx);

        pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
        x = READ_ONCE(pn->lruvec_stats.state_local[idx]);
#ifdef CONFIG_SMP
        if (x < 0)
                x = 0;
#endif
        return x;
}

void mem_cgroup_flush_stats(struct mem_cgroup *memcg);
void mem_cgroup_flush_stats_ratelimited(struct mem_cgroup *memcg);

void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
                              int val);
void __mod_lruvec_kmem_state(void *p, enum node_stat_item idx, int val);

static inline void mod_lruvec_kmem_state(void *p, enum node_stat_item idx,
                                         int val)
{
        unsigned long flags;

        local_irq_save(flags);
        __mod_lruvec_kmem_state(p, idx, val);
        local_irq_restore(flags);
}

static inline void mod_memcg_lruvec_state(struct lruvec *lruvec,
                                          enum node_stat_item idx, int val)
{
        unsigned long flags;

        local_irq_save(flags);
        __mod_memcg_lruvec_state(lruvec, idx, val);
        local_irq_restore(flags);
}

void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx,
                          unsigned long count);

static inline void count_memcg_events(struct mem_cgroup *memcg,
                                      enum vm_event_item idx,
                                      unsigned long count)
{
        unsigned long flags;

        local_irq_save(flags);
        __count_memcg_events(memcg, idx, count);
        local_irq_restore(flags);
}

static inline void count_memcg_folio_events(struct folio *folio,
                enum vm_event_item idx, unsigned long nr)
{
        struct mem_cgroup *memcg = folio_memcg(folio);

        if (memcg)
                count_memcg_events(memcg, idx, nr);
}

static inline void count_memcg_event_mm(struct mm_struct *mm,
                                        enum vm_event_item idx)
{
        struct mem_cgroup *memcg;

        if (mem_cgroup_disabled())
                return;

        rcu_read_lock();
        memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
        if (likely(memcg))
                count_memcg_events(memcg, idx, 1);
        rcu_read_unlock();
}

static inline void memcg_memory_event(struct mem_cgroup *memcg,
                                      enum memcg_memory_event event)
{
        bool swap_event = event == MEMCG_SWAP_HIGH || event == MEMCG_SWAP_MAX ||
                          event == MEMCG_SWAP_FAIL;

        atomic_long_inc(&memcg->memory_events_local[event]);
        if (!swap_event)
                cgroup_file_notify(&memcg->events_local_file);

        do {
                atomic_long_inc(&memcg->memory_events[event]);
                if (swap_event)
                        cgroup_file_notify(&memcg->swap_events_file);
                else
                        cgroup_file_notify(&memcg->events_file);

                if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
                        break;
                if (cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_LOCAL_EVENTS)
                        break;
        } while ((memcg = parent_mem_cgroup(memcg)) &&
                 !mem_cgroup_is_root(memcg));
}

static inline void memcg_memory_event_mm(struct mm_struct *mm,
                                         enum memcg_memory_event event)
{
        struct mem_cgroup *memcg;

        if (mem_cgroup_disabled())
                return;

        rcu_read_lock();
        memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
        if (likely(memcg))
                memcg_memory_event(memcg, event);
        rcu_read_unlock();
}

void split_page_memcg(struct page *head, int old_order, int new_order);

unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
                                                gfp_t gfp_mask,
                                                unsigned long *total_scanned);

#else /* CONFIG_MEMCG */

#define MEM_CGROUP_ID_SHIFT     0

static inline struct mem_cgroup *folio_memcg(struct folio *folio)
{
        return NULL;
}

static inline struct mem_cgroup *page_memcg(struct page *page)
{
        return NULL;
}

static inline struct mem_cgroup *folio_memcg_rcu(struct folio *folio)
{
        WARN_ON_ONCE(!rcu_read_lock_held());
        return NULL;
}

static inline struct mem_cgroup *folio_memcg_check(struct folio *folio)
{
        return NULL;
}

static inline struct mem_cgroup *page_memcg_check(struct page *page)
{
        return NULL;
}

static inline struct mem_cgroup *get_mem_cgroup_from_objcg(struct obj_cgroup *objcg)
{
        return NULL;
}

static inline bool folio_memcg_kmem(struct folio *folio)
{
        return false;
}

static inline bool PageMemcgKmem(struct page *page)
{
        return false;
}

static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
{
        return true;
}

static inline bool mem_cgroup_disabled(void)
{
        return true;
}

static inline void memcg_memory_event(struct mem_cgroup *memcg,
                                      enum memcg_memory_event event)
{
}

static inline void memcg_memory_event_mm(struct mm_struct *mm,
                                         enum memcg_memory_event event)
{
}

static inline void mem_cgroup_protection(struct mem_cgroup *root,
                                         struct mem_cgroup *memcg,
                                         unsigned long *min,
                                         unsigned long *low)
{
        *min = *low = 0;
}

static inline void mem_cgroup_calculate_protection(struct mem_cgroup *root,
                                                   struct mem_cgroup *memcg)
{
}

static inline bool mem_cgroup_unprotected(struct mem_cgroup *target,
                                          struct mem_cgroup *memcg)
{
        return true;
}
static inline bool mem_cgroup_below_low(struct mem_cgroup *target,
                                        struct mem_cgroup *memcg)
{
        return false;
}

static inline bool mem_cgroup_below_min(struct mem_cgroup *target,
                                        struct mem_cgroup *memcg)
{
        return false;
}

static inline void mem_cgroup_commit_charge(struct folio *folio,
                struct mem_cgroup *memcg)
{
}

static inline int mem_cgroup_charge(struct folio *folio,
                struct mm_struct *mm, gfp_t gfp)
{
        return 0;
}

static inline int mem_cgroup_hugetlb_try_charge(struct mem_cgroup *memcg,
                gfp_t gfp, long nr_pages)
{
        return 0;
}

static inline int mem_cgroup_swapin_charge_folio(struct folio *folio,
                        struct mm_struct *mm, gfp_t gfp, swp_entry_t entry)
{
        return 0;
}

static inline void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry)
{
}

static inline void mem_cgroup_uncharge(struct folio *folio)
{
}

static inline void mem_cgroup_uncharge_folios(struct folio_batch *folios)
{
}

static inline void mem_cgroup_cancel_charge(struct mem_cgroup *memcg,
                unsigned int nr_pages)
{
}

static inline void mem_cgroup_replace_folio(struct folio *old,
                struct folio *new)
{
}

static inline void mem_cgroup_migrate(struct folio *old, struct folio *new)
{
}

static inline struct lruvec *mem_cgroup_lruvec(struct mem_cgroup *memcg,
                                               struct pglist_data *pgdat)
{
        return &pgdat->__lruvec;
}

static inline struct lruvec *folio_lruvec(struct folio *folio)
{
        struct pglist_data *pgdat = folio_pgdat(folio);
        return &pgdat->__lruvec;
}

static inline
void lruvec_memcg_debug(struct lruvec *lruvec, struct folio *folio)
{
}

static inline struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
{
        return NULL;
}

static inline bool mm_match_cgroup(struct mm_struct *mm,
                struct mem_cgroup *memcg)
{
        return true;
}

static inline struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
{
        return NULL;
}

static inline struct mem_cgroup *get_mem_cgroup_from_current(void)
{
        return NULL;
}

static inline
struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css)
{
        return NULL;
}

static inline void obj_cgroup_put(struct obj_cgroup *objcg)
{
}

static inline bool mem_cgroup_tryget(struct mem_cgroup *memcg)
{
        return true;
}

static inline bool mem_cgroup_tryget_online(struct mem_cgroup *memcg)
{
        return true;
}

static inline void mem_cgroup_put(struct mem_cgroup *memcg)
{
}

static inline struct lruvec *folio_lruvec_lock(struct folio *folio)
{
        struct pglist_data *pgdat = folio_pgdat(folio);

        spin_lock(&pgdat->__lruvec.lru_lock);
        return &pgdat->__lruvec;
}

static inline struct lruvec *folio_lruvec_lock_irq(struct folio *folio)
{
        struct pglist_data *pgdat = folio_pgdat(folio);

        spin_lock_irq(&pgdat->__lruvec.lru_lock);
        return &pgdat->__lruvec;
}

static inline struct lruvec *folio_lruvec_lock_irqsave(struct folio *folio,
                unsigned long *flagsp)
{
        struct pglist_data *pgdat = folio_pgdat(folio);

        spin_lock_irqsave(&pgdat->__lruvec.lru_lock, *flagsp);
        return &pgdat->__lruvec;
}

static inline struct mem_cgroup *
mem_cgroup_iter(struct mem_cgroup *root,
                struct mem_cgroup *prev,
                struct mem_cgroup_reclaim_cookie *reclaim)
{
        return NULL;
}

static inline void mem_cgroup_iter_break(struct mem_cgroup *root,
                                         struct mem_cgroup *prev)
{
}

static inline void mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
                int (*fn)(struct task_struct *, void *), void *arg)
{
}

static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
{
        return 0;
}

static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
{
        WARN_ON_ONCE(id);
        /* XXX: This should always return root_mem_cgroup */
        return NULL;
}

#ifdef CONFIG_SHRINKER_DEBUG
static inline unsigned long mem_cgroup_ino(struct mem_cgroup *memcg)
{
        return 0;
}

static inline struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino)
{
        return NULL;
}
#endif

static inline struct mem_cgroup *mem_cgroup_from_seq(struct seq_file *m)
{
        return NULL;
}

static inline struct mem_cgroup *lruvec_memcg(struct lruvec *lruvec)
{
        return NULL;
}

static inline bool mem_cgroup_online(struct mem_cgroup *memcg)
{
        return true;
}

static inline
unsigned long mem_cgroup_get_zone_lru_size(struct lruvec *lruvec,
                enum lru_list lru, int zone_idx)
{
        return 0;
}

static inline unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg)
{
        return 0;
}

static inline unsigned long mem_cgroup_size(struct mem_cgroup *memcg)
{
        return 0;
}

static inline void
mem_cgroup_print_oom_context(struct mem_cgroup *memcg, struct task_struct *p)
{
}

static inline void
mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
{
}

static inline void folio_memcg_lock(struct folio *folio)
{
}

static inline void folio_memcg_unlock(struct folio *folio)
{
}

static inline bool mem_cgroup_trylock_pages(struct mem_cgroup *memcg)
{
        /* to match folio_memcg_rcu() */
        rcu_read_lock();
        return true;
}

static inline void mem_cgroup_unlock_pages(void)
{
        rcu_read_unlock();
}

static inline void mem_cgroup_handle_over_high(gfp_t gfp_mask)
{
}

static inline void mem_cgroup_enter_user_fault(void)
{
}

static inline void mem_cgroup_exit_user_fault(void)
{
}

static inline bool task_in_memcg_oom(struct task_struct *p)
{
        return false;
}

static inline bool mem_cgroup_oom_synchronize(bool wait)
{
        return false;
}

static inline struct mem_cgroup *mem_cgroup_get_oom_group(
        struct task_struct *victim, struct mem_cgroup *oom_domain)
{
        return NULL;
}

static inline void mem_cgroup_print_oom_group(struct mem_cgroup *memcg)
{
}

static inline void __mod_memcg_state(struct mem_cgroup *memcg,
                                     int idx,
                                     int nr)
{
}

static inline void mod_memcg_state(struct mem_cgroup *memcg,
                                   int idx,
                                   int nr)
{
}

static inline void mod_memcg_page_state(struct page *page,
                                        int idx, int val)
{
}

static inline unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
{
        return 0;
}

static inline unsigned long lruvec_page_state(struct lruvec *lruvec,
                                              enum node_stat_item idx)
{
        return node_page_state(lruvec_pgdat(lruvec), idx);
}

static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec,
                                                    enum node_stat_item idx)
{
        return node_page_state(lruvec_pgdat(lruvec), idx);
}

static inline void mem_cgroup_flush_stats(struct mem_cgroup *memcg)
{
}

static inline void mem_cgroup_flush_stats_ratelimited(struct mem_cgroup *memcg)
{
}

static inline void __mod_memcg_lruvec_state(struct lruvec *lruvec,
                                            enum node_stat_item idx, int val)
{
}

static inline void __mod_lruvec_kmem_state(void *p, enum node_stat_item idx,
                                           int val)
{
        struct page *page = virt_to_head_page(p);

        __mod_node_page_state(page_pgdat(page), idx, val);
}

static inline void mod_lruvec_kmem_state(void *p, enum node_stat_item idx,
                                         int val)
{
        struct page *page = virt_to_head_page(p);

        mod_node_page_state(page_pgdat(page), idx, val);
}

static inline void count_memcg_events(struct mem_cgroup *memcg,
                                      enum vm_event_item idx,
                                      unsigned long count)
{
}

static inline void __count_memcg_events(struct mem_cgroup *memcg,
                                        enum vm_event_item idx,
                                        unsigned long count)
{
}

static inline void count_memcg_folio_events(struct folio *folio,
                enum vm_event_item idx, unsigned long nr)
{
}

static inline
void count_memcg_event_mm(struct mm_struct *mm, enum vm_event_item idx)
{
}

static inline void split_page_memcg(struct page *head, int old_order, int new_order)
{
}

static inline
unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
                                            gfp_t gfp_mask,
                                            unsigned long *total_scanned)
{
        return 0;
}
#endif /* CONFIG_MEMCG */

static inline void __inc_lruvec_kmem_state(void *p, enum node_stat_item idx)
{
        __mod_lruvec_kmem_state(p, idx, 1);
}

static inline void __dec_lruvec_kmem_state(void *p, enum node_stat_item idx)
{
        __mod_lruvec_kmem_state(p, idx, -1);
}

static inline struct lruvec *parent_lruvec(struct lruvec *lruvec)
{
        struct mem_cgroup *memcg;

        memcg = lruvec_memcg(lruvec);
        if (!memcg)
                return NULL;
        memcg = parent_mem_cgroup(memcg);
        if (!memcg)
                return NULL;
        return mem_cgroup_lruvec(memcg, lruvec_pgdat(lruvec));
}

static inline void unlock_page_lruvec(struct lruvec *lruvec)
{
        spin_unlock(&lruvec->lru_lock);
}

static inline void unlock_page_lruvec_irq(struct lruvec *lruvec)
{
        spin_unlock_irq(&lruvec->lru_lock);
}

static inline void unlock_page_lruvec_irqrestore(struct lruvec *lruvec,
                unsigned long flags)
{
        spin_unlock_irqrestore(&lruvec->lru_lock, flags);
}

/* Test requires a stable page->memcg binding, see page_memcg() */
static inline bool folio_matches_lruvec(struct folio *folio,
                struct lruvec *lruvec)
{
        return lruvec_pgdat(lruvec) == folio_pgdat(folio) &&
               lruvec_memcg(lruvec) == folio_memcg(folio);
}

/* Don't lock again iff page's lruvec locked */
static inline struct lruvec *folio_lruvec_relock_irq(struct folio *folio,
                struct lruvec *locked_lruvec)
{
        if (locked_lruvec) {
                if (folio_matches_lruvec(folio, locked_lruvec))
                        return locked_lruvec;

                unlock_page_lruvec_irq(locked_lruvec);
        }

        return folio_lruvec_lock_irq(folio);
}

/* Don't lock again iff folio's lruvec locked */
static inline void folio_lruvec_relock_irqsave(struct folio *folio,
                struct lruvec **lruvecp, unsigned long *flags)
{
        if (*lruvecp) {
                if (folio_matches_lruvec(folio, *lruvecp))
                        return;

                unlock_page_lruvec_irqrestore(*lruvecp, *flags);
        }

        *lruvecp = folio_lruvec_lock_irqsave(folio, flags);
}

#ifdef CONFIG_CGROUP_WRITEBACK

struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb);
void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
                         unsigned long *pheadroom, unsigned long *pdirty,
                         unsigned long *pwriteback);

void mem_cgroup_track_foreign_dirty_slowpath(struct folio *folio,
                                             struct bdi_writeback *wb);

static inline void mem_cgroup_track_foreign_dirty(struct folio *folio,
                                                  struct bdi_writeback *wb)
{
        struct mem_cgroup *memcg;

        if (mem_cgroup_disabled())
                return;

        memcg = folio_memcg(folio);
        if (unlikely(memcg && &memcg->css != wb->memcg_css))
                mem_cgroup_track_foreign_dirty_slowpath(folio, wb);
}

void mem_cgroup_flush_foreign(struct bdi_writeback *wb);

#else   /* CONFIG_CGROUP_WRITEBACK */

static inline struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
{
        return NULL;
}

static inline void mem_cgroup_wb_stats(struct bdi_writeback *wb,
                                       unsigned long *pfilepages,
                                       unsigned long *pheadroom,
                                       unsigned long *pdirty,
                                       unsigned long *pwriteback)
{
}

static inline void mem_cgroup_track_foreign_dirty(struct folio *folio,
                                                  struct bdi_writeback *wb)
{
}

static inline void mem_cgroup_flush_foreign(struct bdi_writeback *wb)
{
}

#endif  /* CONFIG_CGROUP_WRITEBACK */

struct sock;
bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages,
                             gfp_t gfp_mask);
void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages);
#ifdef CONFIG_MEMCG
extern struct static_key_false memcg_sockets_enabled_key;
#define mem_cgroup_sockets_enabled static_branch_unlikely(&memcg_sockets_enabled_key)
void mem_cgroup_sk_alloc(struct sock *sk);
void mem_cgroup_sk_free(struct sock *sk);
static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
{
        if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
                return !!memcg->tcpmem_pressure;
        do {
                if (time_before(jiffies, READ_ONCE(memcg->socket_pressure)))
                        return true;
        } while ((memcg = parent_mem_cgroup(memcg)));
        return false;
}

int alloc_shrinker_info(struct mem_cgroup *memcg);
void free_shrinker_info(struct mem_cgroup *memcg);
void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id);
void reparent_shrinker_deferred(struct mem_cgroup *memcg);
#else
#define mem_cgroup_sockets_enabled 0
static inline void mem_cgroup_sk_alloc(struct sock *sk) { };
static inline void mem_cgroup_sk_free(struct sock *sk) { };
static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
{
        return false;
}

static inline void set_shrinker_bit(struct mem_cgroup *memcg,
                                    int nid, int shrinker_id)
{
}
#endif

#ifdef CONFIG_MEMCG_KMEM
bool mem_cgroup_kmem_disabled(void);
int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order);
void __memcg_kmem_uncharge_page(struct page *page, int order);

/*
 * The returned objcg pointer is safe to use without additional
 * protection within a scope. The scope is defined either by
 * the current task (similar to the "current" global variable)
 * or by set_active_memcg() pair.
 * Please, use obj_cgroup_get() to get a reference if the pointer
 * needs to be used outside of the local scope.
 */
struct obj_cgroup *current_obj_cgroup(void);
struct obj_cgroup *get_obj_cgroup_from_folio(struct folio *folio);

static inline struct obj_cgroup *get_obj_cgroup_from_current(void)
{
        struct obj_cgroup *objcg = current_obj_cgroup();

        if (objcg)
                obj_cgroup_get(objcg);

        return objcg;
}

int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size);
void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size);

extern struct static_key_false memcg_bpf_enabled_key;
static inline bool memcg_bpf_enabled(void)
{
        return static_branch_likely(&memcg_bpf_enabled_key);
}

extern struct static_key_false memcg_kmem_online_key;

static inline bool memcg_kmem_online(void)
{
        return static_branch_likely(&memcg_kmem_online_key);
}

static inline int memcg_kmem_charge_page(struct page *page, gfp_t gfp,
                                         int order)
{
        if (memcg_kmem_online())
                return __memcg_kmem_charge_page(page, gfp, order);
        return 0;
}

static inline void memcg_kmem_uncharge_page(struct page *page, int order)
{
        if (memcg_kmem_online())
                __memcg_kmem_uncharge_page(page, order);
}

/*
 * A helper for accessing memcg's kmem_id, used for getting
 * corresponding LRU lists.
 */
static inline int memcg_kmem_id(struct mem_cgroup *memcg)
{
        return memcg ? memcg->kmemcg_id : -1;
}

struct mem_cgroup *mem_cgroup_from_obj(void *p);
struct mem_cgroup *mem_cgroup_from_slab_obj(void *p);

static inline void count_objcg_event(struct obj_cgroup *objcg,
                                     enum vm_event_item idx)
{
        struct mem_cgroup *memcg;

        if (!memcg_kmem_online())
                return;

        rcu_read_lock();
        memcg = obj_cgroup_memcg(objcg);
        count_memcg_events(memcg, idx, 1);
        rcu_read_unlock();
}

#else
static inline bool mem_cgroup_kmem_disabled(void)
{
        return true;
}

static inline int memcg_kmem_charge_page(struct page *page, gfp_t gfp,
                                         int order)
{
        return 0;
}

static inline void memcg_kmem_uncharge_page(struct page *page, int order)
{
}

static inline int __memcg_kmem_charge_page(struct page *page, gfp_t gfp,
                                           int order)
{
        return 0;
}

static inline void __memcg_kmem_uncharge_page(struct page *page, int order)
{
}

static inline struct obj_cgroup *get_obj_cgroup_from_folio(struct folio *folio)
{
        return NULL;
}

static inline bool memcg_bpf_enabled(void)
{
        return false;
}

static inline bool memcg_kmem_online(void)
{
        return false;
}

static inline int memcg_kmem_id(struct mem_cgroup *memcg)
{
        return -1;
}

static inline struct mem_cgroup *mem_cgroup_from_obj(void *p)
{
        return NULL;
}

static inline struct mem_cgroup *mem_cgroup_from_slab_obj(void *p)
{
        return NULL;
}

static inline void count_objcg_event(struct obj_cgroup *objcg,
                                     enum vm_event_item idx)
{
}

#endif /* CONFIG_MEMCG_KMEM */

#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
bool obj_cgroup_may_zswap(struct obj_cgroup *objcg);
void obj_cgroup_charge_zswap(struct obj_cgroup *objcg, size_t size);
void obj_cgroup_uncharge_zswap(struct obj_cgroup *objcg, size_t size);
bool mem_cgroup_zswap_writeback_enabled(struct mem_cgroup *memcg);
#else
static inline bool obj_cgroup_may_zswap(struct obj_cgroup *objcg)
{
        return true;
}
static inline void obj_cgroup_charge_zswap(struct obj_cgroup *objcg,
                                           size_t size)
{
}
static inline void obj_cgroup_uncharge_zswap(struct obj_cgroup *objcg,
                                             size_t size)
{
}
static inline bool mem_cgroup_zswap_writeback_enabled(struct mem_cgroup *memcg)
{
        /* if zswap is disabled, do not block pages going to the swapping device */
        return true;
}
#endif

#endif /* _LINUX_MEMCONTROL_H */