mm/memcontrol: make mem_cgroup_inactive_anon_is_low() return bool

[linux-2.6/btrfs-unstable.git] / include / linux / memcontrol.h

/* 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>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#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/page_counter.h>
#include <linux/vmpressure.h>
#include <linux/eventfd.h>
#include <linux/mmzone.h>
#include <linux/writeback.h>

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

/*
 * The corresponding mem_cgroup_stat_names is defined in mm/memcontrol.c,
 * These two lists should keep in accord with each other.
 */
enum mem_cgroup_stat_index {
        /*
         * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
         */
        MEM_CGROUP_STAT_CACHE,          /* # of pages charged as cache */
        MEM_CGROUP_STAT_RSS,            /* # of pages charged as anon rss */
        MEM_CGROUP_STAT_RSS_HUGE,       /* # of pages charged as anon huge */
        MEM_CGROUP_STAT_FILE_MAPPED,    /* # of pages charged as file rss */
        MEM_CGROUP_STAT_DIRTY,          /* # of dirty pages in page cache */
        MEM_CGROUP_STAT_WRITEBACK,      /* # of pages under writeback */
        MEM_CGROUP_STAT_SWAP,           /* # of pages, swapped out */
        MEM_CGROUP_STAT_NSTATS,
};

struct mem_cgroup_reclaim_cookie {
        struct zone *zone;
        int priority;
        unsigned int generation;
};

enum mem_cgroup_events_index {
        MEM_CGROUP_EVENTS_PGPGIN,       /* # of pages paged in */
        MEM_CGROUP_EVENTS_PGPGOUT,      /* # of pages paged out */
        MEM_CGROUP_EVENTS_PGFAULT,      /* # of page-faults */
        MEM_CGROUP_EVENTS_PGMAJFAULT,   /* # of major page-faults */
        MEM_CGROUP_EVENTS_NSTATS,
        /* default hierarchy events */
        MEMCG_LOW = MEM_CGROUP_EVENTS_NSTATS,
        MEMCG_HIGH,
        MEMCG_MAX,
        MEMCG_OOM,
        MEMCG_NR_EVENTS,
};

/*
 * Per memcg event counter is incremented at every pagein/pageout. With THP,
 * it will be incremated by the number of pages. This counter is used for
 * for 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_TARGET_NUMAINFO,
        MEM_CGROUP_NTARGETS,
};

/*
 * Bits in struct cg_proto.flags
 */
enum cg_proto_flags {
        /* Currently active and new sockets should be assigned to cgroups */
        MEMCG_SOCK_ACTIVE,
        /* It was ever activated; we must disarm static keys on destruction */
        MEMCG_SOCK_ACTIVATED,
};

struct cg_proto {
        struct page_counter     memory_allocated;       /* Current allocated memory. */
        struct percpu_counter   sockets_allocated;      /* Current number of sockets. */
        int                     memory_pressure;
        long                    sysctl_mem[3];
        unsigned long           flags;
        /*
         * memcg field is used to find which memcg we belong directly
         * Each memcg struct can hold more than one cg_proto, so container_of
         * won't really cut.
         *
         * The elegant solution would be having an inverse function to
         * proto_cgroup in struct proto, but that means polluting the structure
         * for everybody, instead of just for memcg users.
         */
        struct mem_cgroup       *memcg;
};

#ifdef CONFIG_MEMCG
struct mem_cgroup_stat_cpu {
        long count[MEM_CGROUP_STAT_NSTATS];
        unsigned long events[MEMCG_NR_EVENTS];
        unsigned long nr_page_events;
        unsigned long targets[MEM_CGROUP_NTARGETS];
};

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

/*
 * per-zone information in memory controller.
 */
struct mem_cgroup_per_zone {
        struct lruvec           lruvec;
        unsigned long           lru_size[NR_LRU_LISTS];

        struct mem_cgroup_reclaim_iter  iter[DEF_PRIORITY + 1];

        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_per_node {
        struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
};

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[0];
};

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;
};

/*
 * 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;

        /* Accounted resources */
        struct page_counter memory;
        struct page_counter memsw;
        struct page_counter kmem;

        /* Normal memory consumption range */
        unsigned long low;
        unsigned long high;

        unsigned long soft_limit;

        /* vmpressure notifications */
        struct vmpressure vmpressure;

        /* css_online() has been completed */
        int initialized;

        /*
         * Should the accounting and control be hierarchical, per subtree?
         */
        bool use_hierarchy;

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

        int     swappiness;
        /* 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;

        /*
         * 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;
        /*
         * set > 0 if pages under this cgroup are moving to other cgroup.
         */
        atomic_t                moving_account;
        /* taken only while moving_account > 0 */
        spinlock_t              move_lock;
        struct task_struct      *move_lock_task;
        unsigned long           move_lock_flags;
        /*
         * percpu counter.
         */
        struct mem_cgroup_stat_cpu __percpu *stat;

#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
        struct cg_proto tcp_mem;
#endif
#if defined(CONFIG_MEMCG_KMEM)
        /* Index in the kmem_cache->memcg_params.memcg_caches array */
        int kmemcg_id;
        bool kmem_acct_activated;
        bool kmem_acct_active;
#endif

        int last_scanned_node;
#if MAX_NUMNODES > 1
        nodemask_t      scan_nodes;
        atomic_t        numainfo_events;
        atomic_t        numainfo_updating;
#endif

#ifdef CONFIG_CGROUP_WRITEBACK
        struct list_head cgwb_list;
        struct wb_domain cgwb_domain;
#endif

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

        struct mem_cgroup_per_node *nodeinfo[0];
        /* WARNING: nodeinfo must be the last member here */
};
extern struct cgroup_subsys_state *mem_cgroup_root_css;

/**
 * mem_cgroup_events - count memory events against a cgroup
 * @memcg: the memory cgroup
 * @idx: the event index
 * @nr: the number of events to account for
 */
static inline void mem_cgroup_events(struct mem_cgroup *memcg,
                       enum mem_cgroup_events_index idx,
                       unsigned int nr)
{
        this_cpu_add(memcg->stat->events[idx], nr);
}

bool mem_cgroup_low(struct mem_cgroup *root, struct mem_cgroup *memcg);

int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
                          gfp_t gfp_mask, struct mem_cgroup **memcgp);
void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,
                              bool lrucare);
void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg);
void mem_cgroup_uncharge(struct page *page);
void mem_cgroup_uncharge_list(struct list_head *page_list);

void mem_cgroup_migrate(struct page *oldpage, struct page *newpage,
                        bool lrucare);

struct lruvec *mem_cgroup_zone_lruvec(struct zone *, struct mem_cgroup *);
struct lruvec *mem_cgroup_page_lruvec(struct page *, struct zone *);

bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg);
struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg);

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

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 *);

static inline bool mem_cgroup_is_descendant(struct mem_cgroup *memcg,
                              struct mem_cgroup *root)
{
        if (root == memcg)
                return true;
        if (!root->use_hierarchy)
                return false;
        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_page(struct page *page);
ino_t page_cgroup_ino(struct page *page);

static inline bool mem_cgroup_disabled(void)
{
        if (memory_cgrp_subsys.disabled)
                return true;
        return false;
}

/*
 * For memory reclaim.
 */
int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);

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

static inline bool mem_cgroup_lruvec_online(struct lruvec *lruvec)
{
        struct mem_cgroup_per_zone *mz;
        struct mem_cgroup *memcg;

        if (mem_cgroup_disabled())
                return true;

        mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
        memcg = mz->memcg;

        return !!(memcg->css.flags & CSS_ONLINE);
}

static inline
unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
{
        struct mem_cgroup_per_zone *mz;

        mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
        return mz->lru_size[lru];
}

static inline bool mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
{
        unsigned long inactive_ratio;
        unsigned long inactive;
        unsigned long active;
        unsigned long gb;

        inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON);
        active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON);

        gb = (inactive + active) >> (30 - PAGE_SHIFT);
        if (gb)
                inactive_ratio = int_sqrt(10 * gb);
        else
                inactive_ratio = 1;

        return inactive * inactive_ratio < active;
}

void mem_cgroup_handle_over_high(void);

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

static inline void mem_cgroup_oom_enable(void)
{
        WARN_ON(current->memcg_may_oom);
        current->memcg_may_oom = 1;
}

static inline void mem_cgroup_oom_disable(void)
{
        WARN_ON(!current->memcg_may_oom);
        current->memcg_may_oom = 0;
}

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

bool mem_cgroup_oom_synchronize(bool wait);

#ifdef CONFIG_MEMCG_SWAP
extern int do_swap_account;
#endif

struct mem_cgroup *mem_cgroup_begin_page_stat(struct page *page);
void mem_cgroup_end_page_stat(struct mem_cgroup *memcg);

/**
 * mem_cgroup_update_page_stat - update page state statistics
 * @memcg: memcg to account against
 * @idx: page state item to account
 * @val: number of pages (positive or negative)
 *
 * See mem_cgroup_begin_page_stat() for locking requirements.
 */
static inline void mem_cgroup_update_page_stat(struct mem_cgroup *memcg,
                                 enum mem_cgroup_stat_index idx, int val)
{
        VM_BUG_ON(!rcu_read_lock_held());

        if (memcg)
                this_cpu_add(memcg->stat->count[idx], val);
}

static inline void mem_cgroup_inc_page_stat(struct mem_cgroup *memcg,
                                            enum mem_cgroup_stat_index idx)
{
        mem_cgroup_update_page_stat(memcg, idx, 1);
}

static inline void mem_cgroup_dec_page_stat(struct mem_cgroup *memcg,
                                            enum mem_cgroup_stat_index idx)
{
        mem_cgroup_update_page_stat(memcg, idx, -1);
}

unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
                                                gfp_t gfp_mask,
                                                unsigned long *total_scanned);

static inline void mem_cgroup_count_vm_event(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 (unlikely(!memcg))
                goto out;

        switch (idx) {
        case PGFAULT:
                this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]);
                break;
        case PGMAJFAULT:
                this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
                break;
        default:
                BUG();
        }
out:
        rcu_read_unlock();
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void mem_cgroup_split_huge_fixup(struct page *head);
#endif

#else /* CONFIG_MEMCG */
struct mem_cgroup;

static inline void mem_cgroup_events(struct mem_cgroup *memcg,
                                     enum mem_cgroup_events_index idx,
                                     unsigned int nr)
{
}

static inline bool mem_cgroup_low(struct mem_cgroup *root,
                                  struct mem_cgroup *memcg)
{
        return false;
}

static inline int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
                                        gfp_t gfp_mask,
                                        struct mem_cgroup **memcgp)
{
        *memcgp = NULL;
        return 0;
}

static inline void mem_cgroup_commit_charge(struct page *page,
                                            struct mem_cgroup *memcg,
                                            bool lrucare)
{
}

static inline void mem_cgroup_cancel_charge(struct page *page,
                                            struct mem_cgroup *memcg)
{
}

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

static inline void mem_cgroup_uncharge_list(struct list_head *page_list)
{
}

static inline void mem_cgroup_migrate(struct page *oldpage,
                                      struct page *newpage,
                                      bool lrucare)
{
}

static inline struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
                                                    struct mem_cgroup *memcg)
{
        return &zone->lruvec;
}

static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
                                                    struct zone *zone)
{
        return &zone->lruvec;
}

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

static inline bool task_in_mem_cgroup(struct task_struct *task,
                                      const struct mem_cgroup *memcg)
{
        return true;
}

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 bool mem_cgroup_disabled(void)
{
        return true;
}

static inline bool
mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
{
        return true;
}

static inline bool mem_cgroup_lruvec_online(struct lruvec *lruvec)
{
        return true;
}

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

static inline void
mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
                              int increment)
{
}

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

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

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

static inline void mem_cgroup_handle_over_high(void)
{
}

static inline void mem_cgroup_oom_enable(void)
{
}

static inline void mem_cgroup_oom_disable(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 void mem_cgroup_inc_page_stat(struct mem_cgroup *memcg,
                                            enum mem_cgroup_stat_index idx)
{
}

static inline void mem_cgroup_dec_page_stat(struct mem_cgroup *memcg,
                                            enum mem_cgroup_stat_index idx)
{
}

static inline
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
                                            gfp_t gfp_mask,
                                            unsigned long *total_scanned)
{
        return 0;
}

static inline void mem_cgroup_split_huge_fixup(struct page *head)
{
}

static inline
void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
{
}
#endif /* CONFIG_MEMCG */

enum {
        UNDER_LIMIT,
        SOFT_LIMIT,
        OVER_LIMIT,
};

#ifdef CONFIG_CGROUP_WRITEBACK

struct list_head *mem_cgroup_cgwb_list(struct mem_cgroup *memcg);
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);

#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)
{
}

#endif  /* CONFIG_CGROUP_WRITEBACK */

struct sock;
#if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
void sock_update_memcg(struct sock *sk);
void sock_release_memcg(struct sock *sk);
#else
static inline void sock_update_memcg(struct sock *sk)
{
}
static inline void sock_release_memcg(struct sock *sk)
{
}
#endif /* CONFIG_INET && CONFIG_MEMCG_KMEM */

#ifdef CONFIG_MEMCG_KMEM
extern struct static_key memcg_kmem_enabled_key;

extern int memcg_nr_cache_ids;
void memcg_get_cache_ids(void);
void memcg_put_cache_ids(void);

/*
 * Helper macro to loop through all memcg-specific caches. Callers must still
 * check if the cache is valid (it is either valid or NULL).
 * the slab_mutex must be held when looping through those caches
 */
#define for_each_memcg_cache_index(_idx)        \
        for ((_idx) = 0; (_idx) < memcg_nr_cache_ids; (_idx)++)

static inline bool memcg_kmem_enabled(void)
{
        return static_key_false(&memcg_kmem_enabled_key);
}

static inline bool memcg_kmem_is_active(struct mem_cgroup *memcg)
{
        return memcg->kmem_acct_active;
}

/*
 * In general, we'll do everything in our power to not incur in any overhead
 * for non-memcg users for the kmem functions. Not even a function call, if we
 * can avoid it.
 *
 * Therefore, we'll inline all those functions so that in the best case, we'll
 * see that kmemcg is off for everybody and proceed quickly.  If it is on,
 * we'll still do most of the flag checking inline. We check a lot of
 * conditions, but because they are pretty simple, they are expected to be
 * fast.
 */
bool __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg,
                                        int order);
void __memcg_kmem_commit_charge(struct page *page,
                                       struct mem_cgroup *memcg, int order);
void __memcg_kmem_uncharge_pages(struct page *page, int order);

/*
 * helper for acessing a memcg's index. It will be used as an index in the
 * child cache array in kmem_cache, and also to derive its name. This function
 * will return -1 when this is not a kmem-limited memcg.
 */
static inline int memcg_cache_id(struct mem_cgroup *memcg)
{
        return memcg ? memcg->kmemcg_id : -1;
}

struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep);
void __memcg_kmem_put_cache(struct kmem_cache *cachep);

struct mem_cgroup *__mem_cgroup_from_kmem(void *ptr);

int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp,
                      unsigned long nr_pages);
void memcg_uncharge_kmem(struct mem_cgroup *memcg, unsigned long nr_pages);

static inline bool __memcg_kmem_bypass(gfp_t gfp)
{
        if (!memcg_kmem_enabled())
                return true;
        if (gfp & __GFP_NOACCOUNT)
                return true;
        if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD))
                return true;
        return false;
}

/**
 * memcg_kmem_newpage_charge: verify if a new kmem allocation is allowed.
 * @gfp: the gfp allocation flags.
 * @memcg: a pointer to the memcg this was charged against.
 * @order: allocation order.
 *
 * returns true if the memcg where the current task belongs can hold this
 * allocation.
 *
 * We return true automatically if this allocation is not to be accounted to
 * any memcg.
 */
static inline bool
memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg, int order)
{
        if (__memcg_kmem_bypass(gfp))
                return true;
        return __memcg_kmem_newpage_charge(gfp, memcg, order);
}

/**
 * memcg_kmem_uncharge_pages: uncharge pages from memcg
 * @page: pointer to struct page being freed
 * @order: allocation order.
 */
static inline void
memcg_kmem_uncharge_pages(struct page *page, int order)
{
        if (memcg_kmem_enabled())
                __memcg_kmem_uncharge_pages(page, order);
}

/**
 * memcg_kmem_commit_charge: embeds correct memcg in a page
 * @page: pointer to struct page recently allocated
 * @memcg: the memcg structure we charged against
 * @order: allocation order.
 *
 * Needs to be called after memcg_kmem_newpage_charge, regardless of success or
 * failure of the allocation. if @page is NULL, this function will revert the
 * charges. Otherwise, it will commit @page to @memcg.
 */
static inline void
memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, int order)
{
        if (memcg_kmem_enabled() && memcg)
                __memcg_kmem_commit_charge(page, memcg, order);
}

/**
 * memcg_kmem_get_cache: selects the correct per-memcg cache for allocation
 * @cachep: the original global kmem cache
 * @gfp: allocation flags.
 *
 * All memory allocated from a per-memcg cache is charged to the owner memcg.
 */
static __always_inline struct kmem_cache *
memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
{
        if (__memcg_kmem_bypass(gfp))
                return cachep;
        return __memcg_kmem_get_cache(cachep);
}

static __always_inline void memcg_kmem_put_cache(struct kmem_cache *cachep)
{
        if (memcg_kmem_enabled())
                __memcg_kmem_put_cache(cachep);
}

static __always_inline struct mem_cgroup *mem_cgroup_from_kmem(void *ptr)
{
        if (!memcg_kmem_enabled())
                return NULL;
        return __mem_cgroup_from_kmem(ptr);
}
#else
#define for_each_memcg_cache_index(_idx)        \
        for (; NULL; )

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

static inline bool memcg_kmem_is_active(struct mem_cgroup *memcg)
{
        return false;
}

static inline bool
memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg, int order)
{
        return true;
}

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

static inline void
memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, int order)
{
}

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

static inline void memcg_get_cache_ids(void)
{
}

static inline void memcg_put_cache_ids(void)
{
}

static inline struct kmem_cache *
memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
{
        return cachep;
}

static inline void memcg_kmem_put_cache(struct kmem_cache *cachep)
{
}

static inline struct mem_cgroup *mem_cgroup_from_kmem(void *ptr)
{
        return NULL;
}
#endif /* CONFIG_MEMCG_KMEM */
#endif /* _LINUX_MEMCONTROL_H */