xref: /linux/include/linux/memcontrol.h (revision 49bda4826843be0ef97a162009a29ea3a63f3935)

/* 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;
struct swap_cluster_info;

/* 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_KMEM,
	MEMCG_ZSWAP_B,
	MEMCG_ZSWAPPED,
	MEMCG_ZSWAP_INCOMP,
	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_SOCK_THROTTLED,
	MEMCG_NR_MEMORY_EVENTS,
};

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

#ifdef CONFIG_MEMCG

#define MEM_CGROUP_ID_SHIFT	16

struct mem_cgroup_private_id {
	int id;
	refcount_t ref;
};

struct memcg_vmstats_percpu;
struct memcg1_events_percpu;
struct memcg_vmstats;
struct lruvec_stats_percpu;
struct lruvec_stats;

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

/*
 * per-node information in memory controller.
 */
struct mem_cgroup_per_node {
	/* Keep the read-only fields at the start */
	struct mem_cgroup	*memcg;		/* Back pointer, we cannot */
						/* use container_of	   */

	struct lruvec_stats_percpu __percpu	*lruvec_stats_percpu;
	struct lruvec_stats			*lruvec_stats;
	struct shrinker_info __rcu	*shrinker_info;

#ifdef CONFIG_MEMCG_V1
	/*
	 * Memcg-v1 only stuff in middle as buffer between read mostly fields
	 * and update often fields to avoid false sharing. If v1 stuff is
	 * not present, an explicit padding is needed.
	 */

	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;
#else
	CACHELINE_PADDING(_pad1_);
#endif

	/* Fields which get updated often at the end. */
	struct lruvec		lruvec;
	CACHELINE_PADDING(_pad2_);
	unsigned long		lru_zone_size[MAX_NR_ZONES][NR_LRU_LISTS];
	struct mem_cgroup_reclaim_iter	iter;

	/*
	 * objcg is wiped out as a part of the objcg repaprenting process.
	 * 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;

#ifdef CONFIG_MEMCG_NMI_SAFETY_REQUIRES_ATOMIC
	/* slab stats for nmi context */
	atomic_t		slab_reclaimable;
	atomic_t		slab_unreclaimable;
#endif
};

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;
	};
	bool is_root;
};

/*
 * 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_private_id id;

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

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

	/* registered local peak watchers */
	struct list_head memory_peaks;
	struct list_head swap_peaks;
	spinlock_t	 peaks_lock;

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

#ifdef 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

	/* vmpressure notifications */
	struct vmpressure vmpressure;

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

	/* 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;

	/* 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];

#ifdef CONFIG_MEMCG_NMI_SAFETY_REQUIRES_ATOMIC
	/* MEMCG_KMEM for nmi context */
	atomic_t		kmem_stat;
#endif
	/*
	 * 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.
	 */
	u64			socket_pressure;
#if BITS_PER_LONG < 64
	seqlock_t		socket_pressure_seqlock;
#endif
	int kmemcg_id;

#ifdef CONFIG_CGROUP_WRITEBACK
	struct list_head cgwb_list;
#endif

	/* Keep the hot per-CPU stats pointer away from memory event counters. */
	struct memcg_vmstats_percpu __percpu *vmstats_percpu
		____cacheline_aligned_in_smp;

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

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

#ifdef CONFIG_MEMCG_V1
	/* Legacy consumer-oriented counters */
	struct page_counter kmem;		/* v1 only */
	struct page_counter tcpmem;		/* v1 only */

	struct memcg1_events_percpu __percpu *events_percpu;

	unsigned long soft_limit;

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

	/* OOM-Killer disable */
	int oom_kill_disable;

	/* 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;

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

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

	int swappiness;
#endif /* CONFIG_MEMCG_V1 */

	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 slabobj_ext vector */
	MEMCG_DATA_OBJEXTS = (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 __OBJEXTS_ALLOC_FAIL	MEMCG_DATA_OBJEXTS
#define __FIRST_OBJEXT_FLAG	__NR_MEMCG_DATA_FLAGS

#else /* CONFIG_MEMCG */

#define __OBJEXTS_ALLOC_FAIL	(1UL << 0)
#define __FIRST_OBJEXT_FLAG	(1UL << 0)

#endif /* CONFIG_MEMCG */

enum objext_flags {
	/*
	 * Use bit 0 with zero other bits to signal that slabobj_ext vector
	 * failed to allocate. The same bit 0 with valid upper bits means
	 * MEMCG_DATA_OBJEXTS.
	 */
	OBJEXTS_ALLOC_FAIL = __OBJEXTS_ALLOC_FAIL,
	__OBJEXTS_FLAG_UNUSED = __FIRST_OBJEXT_FLAG,
	/* the next bit after the last actual flag */
	__NR_OBJEXTS_FLAGS  = (__FIRST_OBJEXT_FLAG << 1),
};

#define OBJEXTS_FLAGS_MASK (__NR_OBJEXTS_FLAGS - 1)

#ifdef CONFIG_MEMCG
/*
 * 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.
 */
static inline struct mem_cgroup *obj_cgroup_memcg(struct obj_cgroup *objcg)
{
	lockdep_assert_once(rcu_read_lock_held() || lockdep_is_held(&cgroup_mutex));
	return READ_ONCE(objcg->memcg);
}

/*
 * folio_objcg - get the object cgroup associated with a 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.
 */
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_OBJEXTS, folio);

	return (struct obj_cgroup *)(memcg_data & ~OBJEXTS_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 folio any of the following ensures folio and objcg binding stability:
 *
 * - the folio lock
 * - LRU isolation
 * - exclusive reference
 *
 * Based on the stable binding of folio and objcg, for a folio any of the
 * following ensures folio and memcg binding stability:
 *
 * - cgroup_mutex
 * - the lruvec lock
 *
 * If the caller only want to ensure that the page counters of memcg are
 * updated correctly, ensure that the binding stability of folio and objcg
 * is sufficient.
 *
 * Note: The caller should hold an rcu read lock or cgroup_mutex to protect
 * memcg associated with a folio from being released.
 */
static inline struct mem_cgroup *folio_memcg(struct folio *folio)
{
	struct obj_cgroup *objcg = folio_objcg(folio);

	return objcg ? obj_cgroup_memcg(objcg) : NULL;
}

/*
 * folio_memcg_charged - If a folio is charged to a memory cgroup.
 * @folio: Pointer to the folio.
 *
 * Returns true if folio is charged to a memory cgroup, otherwise returns false.
 */
static inline bool folio_memcg_charged(struct folio *folio)
{
	return folio->memcg_data != 0;
}

/*
 * 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.
 *
 * The page and objcg or memcg binding rules can refer to folio_memcg().
 *
 * A caller should hold an rcu read lock to protect memcg associated with a
 * page 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);
	struct obj_cgroup *objcg;

	if (memcg_data & MEMCG_DATA_OBJEXTS)
		return NULL;

	objcg = (void *)(memcg_data & ~OBJEXTS_FLAGS_MASK);

	return objcg ? obj_cgroup_memcg(objcg) : NULL;
}

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;
}

/*
 * 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_OBJEXTS, folio);
	return folio->memcg_data & MEMCG_DATA_KMEM;
}

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);
}

/**
 * mem_cgroup_shrink_is_root - is this a global or root-memcg shrink invocation?
 * @sc: shrink_control describing the current shrinker call
 *
 * Returns true when @sc represents a global reclaim shrink (sc->memcg == NULL)
 * or a root-memcg shrink, i.e. not a per-memcg iteration of
 * shrink_slab_memcg(). Filesystems whose ->nr_cached_objects()/
 * ->free_cached_objects() implementations operate on filesystem-global state
 * and do not honour sc->memcg can use this to early-return 0 in per-memcg
 * contexts.
 */
static inline bool mem_cgroup_shrink_is_root(struct shrink_control *sc)
{
	return !sc->memcg || mem_cgroup_is_root(sc->memcg);
}

static inline bool obj_cgroup_is_root(const struct obj_cgroup *objcg)
{
	return objcg->is_root;
}

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,
					 unsigned long *usage)
{
	*min = *low = *usage = 0;

	if (mem_cgroup_disabled())
		return;

	*usage = page_counter_read(&memcg->memory);
	/*
	 * 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);
}

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_charge_hugetlb(struct folio* folio, gfp_t gfp);

int mem_cgroup_swapin_charge_folio(struct folio *folio, unsigned short id,
				   struct mm_struct *mm, gfp_t gfp);

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_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.
 *
 * Call with rcu_read_lock() held to ensure the lifetime of the returned lruvec.
 * Note that this alone will NOT guarantee the stability of the folio->lruvec
 * association; the folio can be reparented to an ancestor if this races with
 * cgroup deletion.
 *
 * Use folio_lruvec_lock() to ensure both lifetime and stability of the binding.
 * Once a lruvec is locked, folio_lruvec() can be called on other folios, and
 * their binding is stable if the returned lruvec matches the one the caller has
 * locked. Useful for lock batching.
 */
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 mem_cgroup *get_mem_cgroup_from_folio(struct folio *folio);

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);

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)
{
	if (obj_cgroup_is_root(objcg))
		return true;
	return percpu_ref_tryget(&objcg->refcnt);
}

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

static inline void obj_cgroup_get(struct obj_cgroup *objcg)
{
	obj_cgroup_get_many(objcg, 1);
}

static inline void obj_cgroup_put(struct obj_cgroup *objcg)
{
	if (objcg && !obj_cgroup_is_root(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_private_id(struct mem_cgroup *memcg)
{
	if (mem_cgroup_disabled())
		return 0;

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

static inline u64 mem_cgroup_id(struct mem_cgroup *memcg)
{
	return memcg ? cgroup_id(memcg->css.cgroup) : 0;
}

struct mem_cgroup *mem_cgroup_get_from_id(u64 id);

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 *get_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 css_is_online(&memcg->css);
}

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

static inline void mem_cgroup_handle_over_high(gfp_t gfp_mask)
{
	if (unlikely(current->memcg_nr_pages_over_high))
		__mem_cgroup_handle_over_high(gfp_mask);
}

unsigned long mem_cgroup_get_max(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);

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);

/* idx can be of type enum memcg_stat_item or node_stat_item */
void mod_memcg_state(struct mem_cgroup *memcg,
		     enum memcg_stat_item idx, int val);

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

	if (mem_cgroup_disabled())
		return;

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

unsigned long memcg_events(struct mem_cgroup *memcg, int event);
unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx);
unsigned long memcg_page_state_output(struct mem_cgroup *memcg, int item);
bool memcg_stat_item_valid(int idx);
bool memcg_vm_event_item_valid(enum vm_event_item idx);
unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx);
unsigned long lruvec_page_state_monotonic(struct lruvec *lruvec,
					  enum node_stat_item idx);
unsigned long lruvec_page_state_local(struct lruvec *lruvec,
				      enum node_stat_item idx);

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

void mod_lruvec_kmem_state(void *p, enum node_stat_item idx, int val);

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)
{
	struct mem_cgroup *memcg;

	if (!folio_memcg_charged(folio))
		return;

	rcu_read_lock();
	memcg = folio_memcg(folio);
	count_memcg_events(memcg, idx, nr);
	rcu_read_unlock();
}

static inline void count_memcg_events_mm(struct mm_struct *mm,
					enum vm_event_item idx, unsigned long count)
{
	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, count);
	rcu_read_unlock();
}

static inline void count_memcg_event_mm(struct mm_struct *mm,
					enum vm_event_item idx)
{
	count_memcg_events_mm(mm, idx, 1);
}

void __memcg_memory_event(struct mem_cgroup *memcg,
			  enum memcg_memory_event event, bool allow_spinning);

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

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 *first, unsigned order);
void folio_split_memcg_refs(struct folio *folio, unsigned old_order,
		unsigned new_order);

static inline u64 cgroup_id_from_mm(struct mm_struct *mm)
{
	struct mem_cgroup *memcg;
	u64 id;

	if (mem_cgroup_disabled())
		return 0;

	rcu_read_lock();
	memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
	if (!memcg)
		memcg = root_mem_cgroup;
	id = cgroup_id(memcg->css.cgroup);
	rcu_read_unlock();
	return id;
}

void mem_cgroup_flush_workqueue(void);

extern int mem_cgroup_init(void);
#else /* CONFIG_MEMCG */

#define MEM_CGROUP_ID_SHIFT	0

#define root_mem_cgroup		(NULL)

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

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

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_shrink_is_root(struct shrink_control *sc)
{
	return true;
}

static inline bool obj_cgroup_is_root(const struct obj_cgroup *objcg)
{
	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,
					 unsigned long *usage)
{
	*min = *low = *usage = 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 int mem_cgroup_charge(struct folio *folio,
		struct mm_struct *mm, gfp_t gfp)
{
	return 0;
}

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

static inline int mem_cgroup_swapin_charge_folio(struct folio *folio,
		 unsigned short id, struct mm_struct *mm, gfp_t gfp)
{
	return 0;
}

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_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 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 *get_mem_cgroup_from_folio(struct folio *folio)
{
	return NULL;
}

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

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

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);

	rcu_read_lock();
	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);

	rcu_read_lock();
	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);

	rcu_read_lock();
	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_private_id(struct mem_cgroup *memcg)
{
	return 0;
}

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

static inline u64 mem_cgroup_id(struct mem_cgroup *memcg)
{
	return 0;
}

static inline struct mem_cgroup *mem_cgroup_get_from_id(u64 id)
{
	return NULL;
}

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 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 mem_cgroup_handle_over_high(gfp_t gfp_mask)
{
}

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,
				   enum memcg_stat_item idx,
				   int nr)
{
}

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

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

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

static inline bool memcg_stat_item_valid(int idx)
{
	return false;
}

static inline bool memcg_vm_event_item_valid(enum vm_event_item idx)
{
	return false;
}

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_monotonic(struct lruvec *lruvec,
							enum node_stat_item idx)
{
	return node_page_state_monotonic(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_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_folio_events(struct folio *folio,
		enum vm_event_item idx, unsigned long nr)
{
}

static inline void count_memcg_events_mm(struct mm_struct *mm,
					enum vm_event_item idx, unsigned long count)
{
}

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

static inline void split_page_memcg(struct page *first, unsigned order)
{
}

static inline void folio_split_memcg_refs(struct folio *folio,
		unsigned old_order, unsigned new_order)
{
}

static inline u64 cgroup_id_from_mm(struct mm_struct *mm)
{
	return 0;
}

static inline void mem_cgroup_flush_workqueue(void) { }

static inline int mem_cgroup_init(void) { return 0; }
#endif /* CONFIG_MEMCG */

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 lruvec_lock_irq(struct lruvec *lruvec)
{
	rcu_read_lock();
	spin_lock_irq(&lruvec->lru_lock);
}

static inline struct lruvec *lruvec_live_lock_irq(struct lruvec *lruvec)
{
#ifdef CONFIG_MEMCG
	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
	struct mem_cgroup *memcg = lruvec_memcg(lruvec);

	rcu_read_lock();

	/*
	 * The memcg can be NULL when the memory controller is disabled.
	 * Otherwise, the caller keeps the memcg owning @lruvec alive.
	 */
	while (unlikely(memcg && css_is_dying(&memcg->css))) {
		memcg = parent_mem_cgroup(memcg);
		lruvec = mem_cgroup_lruvec(memcg, pgdat);
	}

	spin_lock_irq(&lruvec->lru_lock);
#else
	lruvec_lock_irq(lruvec);
#endif

	return lruvec;
}

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

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

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

/* Test requires a stable folio->memcg binding, see folio_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;

		lruvec_unlock_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;

		lruvec_unlock_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;

	if (!folio_memcg_charged(folio))
		return;

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

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;
#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);
void mem_cgroup_sk_inherit(const struct sock *sk, struct sock *newsk);
bool mem_cgroup_sk_charge(const struct sock *sk, unsigned int nr_pages,
			  gfp_t gfp_mask);
void mem_cgroup_sk_uncharge(const struct sock *sk, unsigned int nr_pages);

#if BITS_PER_LONG < 64
static inline void mem_cgroup_set_socket_pressure(struct mem_cgroup *memcg)
{
	u64 val = get_jiffies_64() + HZ;
	unsigned long flags;

	write_seqlock_irqsave(&memcg->socket_pressure_seqlock, flags);
	memcg->socket_pressure = val;
	write_sequnlock_irqrestore(&memcg->socket_pressure_seqlock, flags);
}

static inline u64 mem_cgroup_get_socket_pressure(struct mem_cgroup *memcg)
{
	unsigned int seq;
	u64 val;

	do {
		seq = read_seqbegin(&memcg->socket_pressure_seqlock);
		val = memcg->socket_pressure;
	} while (read_seqretry(&memcg->socket_pressure_seqlock, seq));

	return val;
}
#else
static inline void mem_cgroup_set_socket_pressure(struct mem_cgroup *memcg)
{
	WRITE_ONCE(memcg->socket_pressure, jiffies + HZ);
}

static inline u64 mem_cgroup_get_socket_pressure(struct mem_cgroup *memcg)
{
	return READ_ONCE(memcg->socket_pressure);
}
#endif

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);

static inline int shrinker_id(struct shrinker *shrinker)
{
	return shrinker->id;
}
#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 void mem_cgroup_sk_inherit(const struct sock *sk, struct sock *newsk)
{
}

static inline bool mem_cgroup_sk_charge(const struct sock *sk,
					unsigned int nr_pages,
					gfp_t gfp_mask)
{
	return false;
}

static inline void mem_cgroup_sk_uncharge(const struct sock *sk,
					  unsigned int nr_pages)
{
}

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

static inline int shrinker_id(struct shrinker *shrinker)
{
	return -1;
}
#endif

#ifdef CONFIG_MEMCG
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_virt(void *p);

static inline void count_objcg_events(struct obj_cgroup *objcg,
				      enum vm_event_item idx,
				      unsigned long count)
{
	struct mem_cgroup *memcg;

	if (!memcg_kmem_online())
		return;

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

void mem_cgroup_node_filter_allowed(struct mem_cgroup *memcg, nodemask_t *mask);

void mem_cgroup_show_protected_memory(struct mem_cgroup *memcg);

static inline bool memcg_is_dying(struct mem_cgroup *memcg)
{
	return memcg ? css_is_dying(&memcg->css) : false;
}

#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_virt(void *p)
{
	return NULL;
}

static inline void count_objcg_events(struct obj_cgroup *objcg,
				      enum vm_event_item idx,
				      unsigned long count)
{
}

static inline ino_t page_cgroup_ino(struct page *page)
{
	return 0;
}

static inline void mem_cgroup_node_filter_allowed(struct mem_cgroup *memcg,
						  nodemask_t *mask)
{
}

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

static inline bool memcg_is_dying(struct mem_cgroup *memcg)
{
	return false;
}
#endif /* CONFIG_MEMCG */

#if defined(CONFIG_MEMCG) && 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


/* Cgroup v1-related declarations */

#ifdef CONFIG_MEMCG_V1
unsigned long memcg1_soft_limit_reclaim(pg_data_t *pgdat, int order,
					gfp_t gfp_mask,
					unsigned long *total_scanned);

bool mem_cgroup_oom_synchronize(bool wait);

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

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;
}

#else /* CONFIG_MEMCG_V1 */
static inline
unsigned long memcg1_soft_limit_reclaim(pg_data_t *pgdat, int order,
					gfp_t gfp_mask,
					unsigned long *total_scanned)
{
	return 0;
}

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 void mem_cgroup_enter_user_fault(void)
{
}

static inline void mem_cgroup_exit_user_fault(void)
{
}

#endif /* CONFIG_MEMCG_V1 */

#if defined(CONFIG_MEMCG_V1) && defined(CONFIG_SWAP)

void __memcg1_swapout(struct folio *folio, struct swap_cluster_info *ci);
void memcg1_swapin(struct folio *folio);

#else

static inline void __memcg1_swapout(struct folio *folio,
		struct swap_cluster_info *ci)
{
}

static inline void memcg1_swapin(struct folio *folio)
{
}
#endif

#endif /* _LINUX_MEMCONTROL_H */