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linux/mm/memcontrol.c
Rickard Strandqvist 70bc068c4f mm/memcontrol.c: remove unused mem_cgroup_lru_names_not_uptodate() 
Remove unused mem_cgroup_lru_names_not_uptodate() and move BUILD_BUG_ON()
to the beginning of memcg_stat_show().

This was partially found by using a static code analysis program called
cppcheck.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13 12:42:49 -08:00

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/* memcontrol.c - Memory Controller
*
* Copyright IBM Corporation, 2007
* Author Balbir Singh <balbir@linux.vnet.ibm.com>
*
* Copyright 2007 OpenVZ SWsoft Inc
* Author: Pavel Emelianov <xemul@openvz.org>
*
* Memory thresholds
* Copyright (C) 2009 Nokia Corporation
* Author: Kirill A. Shutemov
*
* Kernel Memory Controller
* Copyright (C) 2012 Parallels Inc. and Google Inc.
* Authors: Glauber Costa and Suleiman Souhlal
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/page_counter.h>
#include <linux/memcontrol.h>
#include <linux/cgroup.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/pagemap.h>
#include <linux/smp.h>
#include <linux/page-flags.h>
#include <linux/backing-dev.h>
#include <linux/bit_spinlock.h>
#include <linux/rcupdate.h>
#include <linux/limits.h>
#include <linux/export.h>
#include <linux/mutex.h>
#include <linux/rbtree.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/spinlock.h>
#include <linux/eventfd.h>
#include <linux/poll.h>
#include <linux/sort.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/vmpressure.h>
#include <linux/mm_inline.h>
#include <linux/swap_cgroup.h>
#include <linux/cpu.h>
#include <linux/oom.h>
#include <linux/lockdep.h>
#include <linux/file.h>
#include "internal.h"
#include <net/sock.h>
#include <net/ip.h>
#include <net/tcp_memcontrol.h>
#include "slab.h"
#include <asm/uaccess.h>
#include <trace/events/vmscan.h>
struct cgroup_subsys memory_cgrp_subsys __read_mostly;
EXPORT_SYMBOL(memory_cgrp_subsys);
#define MEM_CGROUP_RECLAIM_RETRIES 5
static struct mem_cgroup *root_mem_cgroup __read_mostly;
#ifdef CONFIG_MEMCG_SWAP
/* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
int do_swap_account __read_mostly;
/* for remember boot option*/
#ifdef CONFIG_MEMCG_SWAP_ENABLED
static int really_do_swap_account __initdata = 1;
#else
static int really_do_swap_account __initdata;
#endif
#else
#define do_swap_account 0
#endif
static const char * const mem_cgroup_stat_names[] = {
"cache",
"rss",
"rss_huge",
"mapped_file",
"writeback",
"swap",
};
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,
};
static const char * const mem_cgroup_events_names[] = {
"pgpgin",
"pgpgout",
"pgfault",
"pgmajfault",
};
static const char * const mem_cgroup_lru_names[] = {
"inactive_anon",
"active_anon",
"inactive_file",
"active_file",
"unevictable",
};
/*
* 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,
};
#define THRESHOLDS_EVENTS_TARGET 128
#define SOFTLIMIT_EVENTS_TARGET 1024
#define NUMAINFO_EVENTS_TARGET 1024
struct mem_cgroup_stat_cpu {
long count[MEM_CGROUP_STAT_NSTATS];
unsigned long events[MEM_CGROUP_EVENTS_NSTATS];
unsigned long nr_page_events;
unsigned long targets[MEM_CGROUP_NTARGETS];
};
struct 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 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];
};
/*
* Cgroups above their limits are maintained in a RB-Tree, independent of
* their hierarchy representation
*/
struct mem_cgroup_tree_per_zone {
struct rb_root rb_root;
spinlock_t lock;
};
struct mem_cgroup_tree_per_node {
struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
};
struct mem_cgroup_tree {
struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
};
static struct mem_cgroup_tree soft_limit_tree __read_mostly;
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;
};
/* for OOM */
struct mem_cgroup_eventfd_list {
struct list_head list;
struct eventfd_ctx *eventfd;
};
/*
* cgroup_event represents events which userspace want to receive.
*/
struct mem_cgroup_event {
/*
* memcg which the event belongs to.
*/
struct mem_cgroup *memcg;
/*
* eventfd to signal userspace about the event.
*/
struct eventfd_ctx *eventfd;
/*
* Each of these stored in a list by the cgroup.
*/
struct list_head list;
/*
* register_event() callback will be used to add new userspace
* waiter for changes related to this event. Use eventfd_signal()
* on eventfd to send notification to userspace.
*/
int (*register_event)(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd, const char *args);
/*
* unregister_event() callback will be called when userspace closes
* the eventfd or on cgroup removing. This callback must be set,
* if you want provide notification functionality.
*/
void (*unregister_event)(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd);
/*
* All fields below needed to unregister event when
* userspace closes eventfd.
*/
poll_table pt;
wait_queue_head_t *wqh;
wait_queue_t wait;
struct work_struct remove;
};
static void mem_cgroup_threshold(struct mem_cgroup *memcg);
static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
/*
* 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.
*
* TODO: Add a water mark for the memory controller. Reclaim will begin when
* we hit the water mark. May be even add a low water mark, such that
* no reclaim occurs from a cgroup at it's low water mark, this is
* a feature that will be implemented much later in the future.
*/
struct mem_cgroup {
struct cgroup_subsys_state css;
/* Accounted resources */
struct page_counter memory;
struct page_counter memsw;
struct page_counter kmem;
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;
bool oom_lock;
atomic_t under_oom;
atomic_t oom_wakeups;
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;
/*
* percpu counter.
*/
struct mem_cgroup_stat_cpu __percpu *stat;
/*
* used when a cpu is offlined or other synchronizations
* See mem_cgroup_read_stat().
*/
struct mem_cgroup_stat_cpu nocpu_base;
spinlock_t pcp_counter_lock;
#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
struct cg_proto tcp_mem;
#endif
#if defined(CONFIG_MEMCG_KMEM)
/* analogous to slab_common's slab_caches list, but per-memcg;
* protected by memcg_slab_mutex */
struct list_head memcg_slab_caches;
/* Index in the kmem_cache->memcg_params->memcg_caches array */
int kmemcg_id;
#endif
int last_scanned_node;
#if MAX_NUMNODES > 1
nodemask_t scan_nodes;
atomic_t numainfo_events;
atomic_t numainfo_updating;
#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 */
};
#ifdef CONFIG_MEMCG_KMEM
static bool memcg_kmem_is_active(struct mem_cgroup *memcg)
{
return memcg->kmemcg_id >= 0;
}
#endif
/* Stuffs for move charges at task migration. */
/*
* Types of charges to be moved. "move_charge_at_immitgrate" and
* "immigrate_flags" are treated as a left-shifted bitmap of these types.
*/
enum move_type {
MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */
MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */
NR_MOVE_TYPE,
};
/* "mc" and its members are protected by cgroup_mutex */
static struct move_charge_struct {
spinlock_t lock; /* for from, to */
struct mem_cgroup *from;
struct mem_cgroup *to;
unsigned long immigrate_flags;
unsigned long precharge;
unsigned long moved_charge;
unsigned long moved_swap;
struct task_struct *moving_task; /* a task moving charges */
wait_queue_head_t waitq; /* a waitq for other context */
} mc = {
.lock = __SPIN_LOCK_UNLOCKED(mc.lock),
.waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
};
static bool move_anon(void)
{
return test_bit(MOVE_CHARGE_TYPE_ANON, &mc.immigrate_flags);
}
static bool move_file(void)
{
return test_bit(MOVE_CHARGE_TYPE_FILE, &mc.immigrate_flags);
}
/*
* Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
* limit reclaim to prevent infinite loops, if they ever occur.
*/
#define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
#define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
enum charge_type {
MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
MEM_CGROUP_CHARGE_TYPE_ANON,
MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
NR_CHARGE_TYPE,
};
/* for encoding cft->private value on file */
enum res_type {
_MEM,
_MEMSWAP,
_OOM_TYPE,
_KMEM,
};
#define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
#define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
#define MEMFILE_ATTR(val) ((val) & 0xffff)
/* Used for OOM nofiier */
#define OOM_CONTROL (0)
/*
* The memcg_create_mutex will be held whenever a new cgroup is created.
* As a consequence, any change that needs to protect against new child cgroups
* appearing has to hold it as well.
*/
static DEFINE_MUTEX(memcg_create_mutex);
struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s)
{
return s ? container_of(s, struct mem_cgroup, css) : NULL;
}
/* Some nice accessors for the vmpressure. */
struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg)
{
if (!memcg)
memcg = root_mem_cgroup;
return &memcg->vmpressure;
}
struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr)
{
return &container_of(vmpr, struct mem_cgroup, vmpressure)->css;
}
static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
{
return (memcg == root_mem_cgroup);
}
/*
* We restrict the id in the range of [1, 65535], so it can fit into
* an unsigned short.
*/
#define MEM_CGROUP_ID_MAX USHRT_MAX
static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
{
return memcg->css.id;
}
static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
{
struct cgroup_subsys_state *css;
css = css_from_id(id, &memory_cgrp_subsys);
return mem_cgroup_from_css(css);
}
/* Writing them here to avoid exposing memcg's inner layout */
#if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
void sock_update_memcg(struct sock *sk)
{
if (mem_cgroup_sockets_enabled) {
struct mem_cgroup *memcg;
struct cg_proto *cg_proto;
BUG_ON(!sk->sk_prot->proto_cgroup);
/* Socket cloning can throw us here with sk_cgrp already
* filled. It won't however, necessarily happen from
* process context. So the test for root memcg given
* the current task's memcg won't help us in this case.
*
* Respecting the original socket's memcg is a better
* decision in this case.
*/
if (sk->sk_cgrp) {
BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg));
css_get(&sk->sk_cgrp->memcg->css);
return;
}
rcu_read_lock();
memcg = mem_cgroup_from_task(current);
cg_proto = sk->sk_prot->proto_cgroup(memcg);
if (!mem_cgroup_is_root(memcg) &&
memcg_proto_active(cg_proto) &&
css_tryget_online(&memcg->css)) {
sk->sk_cgrp = cg_proto;
}
rcu_read_unlock();
}
}
EXPORT_SYMBOL(sock_update_memcg);
void sock_release_memcg(struct sock *sk)
{
if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
struct mem_cgroup *memcg;
WARN_ON(!sk->sk_cgrp->memcg);
memcg = sk->sk_cgrp->memcg;
css_put(&sk->sk_cgrp->memcg->css);
}
}
struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
{
if (!memcg || mem_cgroup_is_root(memcg))
return NULL;
return &memcg->tcp_mem;
}
EXPORT_SYMBOL(tcp_proto_cgroup);
static void disarm_sock_keys(struct mem_cgroup *memcg)
{
if (!memcg_proto_activated(&memcg->tcp_mem))
return;
static_key_slow_dec(&memcg_socket_limit_enabled);
}
#else
static void disarm_sock_keys(struct mem_cgroup *memcg)
{
}
#endif
#ifdef CONFIG_MEMCG_KMEM
/*
* This will be the memcg's index in each cache's ->memcg_params->memcg_caches.
* The main reason for not using cgroup id for this:
* this works better in sparse environments, where we have a lot of memcgs,
* but only a few kmem-limited. Or also, if we have, for instance, 200
* memcgs, and none but the 200th is kmem-limited, we'd have to have a
* 200 entry array for that.
*
* The current size of the caches array is stored in
* memcg_limited_groups_array_size. It will double each time we have to
* increase it.
*/
static DEFINE_IDA(kmem_limited_groups);
int memcg_limited_groups_array_size;
/*
* MIN_SIZE is different than 1, because we would like to avoid going through
* the alloc/free process all the time. In a small machine, 4 kmem-limited
* cgroups is a reasonable guess. In the future, it could be a parameter or
* tunable, but that is strictly not necessary.
*
* MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
* this constant directly from cgroup, but it is understandable that this is
* better kept as an internal representation in cgroup.c. In any case, the
* cgrp_id space is not getting any smaller, and we don't have to necessarily
* increase ours as well if it increases.
*/
#define MEMCG_CACHES_MIN_SIZE 4
#define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
/*
* A lot of the calls to the cache allocation functions are expected to be
* inlined by the compiler. Since the calls to memcg_kmem_get_cache are
* conditional to this static branch, we'll have to allow modules that does
* kmem_cache_alloc and the such to see this symbol as well
*/
struct static_key memcg_kmem_enabled_key;
EXPORT_SYMBOL(memcg_kmem_enabled_key);
static void memcg_free_cache_id(int id);
static void disarm_kmem_keys(struct mem_cgroup *memcg)
{
if (memcg_kmem_is_active(memcg)) {
static_key_slow_dec(&memcg_kmem_enabled_key);
memcg_free_cache_id(memcg->kmemcg_id);
}
/*
* This check can't live in kmem destruction function,
* since the charges will outlive the cgroup
*/
WARN_ON(page_counter_read(&memcg->kmem));
}
#else
static void disarm_kmem_keys(struct mem_cgroup *memcg)
{
}
#endif /* CONFIG_MEMCG_KMEM */
static void disarm_static_keys(struct mem_cgroup *memcg)
{
disarm_sock_keys(memcg);
disarm_kmem_keys(memcg);
}
static struct mem_cgroup_per_zone *
mem_cgroup_zone_zoneinfo(struct mem_cgroup *memcg, struct zone *zone)
{
int nid = zone_to_nid(zone);
int zid = zone_idx(zone);
return &memcg->nodeinfo[nid]->zoneinfo[zid];
}
struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg)
{
return &memcg->css;
}
static struct mem_cgroup_per_zone *
mem_cgroup_page_zoneinfo(struct mem_cgroup *memcg, struct page *page)
{
int nid = page_to_nid(page);
int zid = page_zonenum(page);
return &memcg->nodeinfo[nid]->zoneinfo[zid];
}
static struct mem_cgroup_tree_per_zone *
soft_limit_tree_node_zone(int nid, int zid)
{
return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
}
static struct mem_cgroup_tree_per_zone *
soft_limit_tree_from_page(struct page *page)
{
int nid = page_to_nid(page);
int zid = page_zonenum(page);
return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
}
static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_zone *mz,
struct mem_cgroup_tree_per_zone *mctz,
unsigned long new_usage_in_excess)
{
struct rb_node **p = &mctz->rb_root.rb_node;
struct rb_node *parent = NULL;
struct mem_cgroup_per_zone *mz_node;
if (mz->on_tree)
return;
mz->usage_in_excess = new_usage_in_excess;
if (!mz->usage_in_excess)
return;
while (*p) {
parent = *p;
mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
tree_node);
if (mz->usage_in_excess < mz_node->usage_in_excess)
p = &(*p)->rb_left;
/*
* We can't avoid mem cgroups that are over their soft
* limit by the same amount
*/
else if (mz->usage_in_excess >= mz_node->usage_in_excess)
p = &(*p)->rb_right;
}
rb_link_node(&mz->tree_node, parent, p);
rb_insert_color(&mz->tree_node, &mctz->rb_root);
mz->on_tree = true;
}
static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz,
struct mem_cgroup_tree_per_zone *mctz)
{
if (!mz->on_tree)
return;
rb_erase(&mz->tree_node, &mctz->rb_root);
mz->on_tree = false;
}
static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz,
struct mem_cgroup_tree_per_zone *mctz)
{
unsigned long flags;
spin_lock_irqsave(&mctz->lock, flags);
__mem_cgroup_remove_exceeded(mz, mctz);
spin_unlock_irqrestore(&mctz->lock, flags);
}
static unsigned long soft_limit_excess(struct mem_cgroup *memcg)
{
unsigned long nr_pages = page_counter_read(&memcg->memory);
unsigned long soft_limit = ACCESS_ONCE(memcg->soft_limit);
unsigned long excess = 0;
if (nr_pages > soft_limit)
excess = nr_pages - soft_limit;
return excess;
}
static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
{
unsigned long excess;
struct mem_cgroup_per_zone *mz;
struct mem_cgroup_tree_per_zone *mctz;
mctz = soft_limit_tree_from_page(page);
/*
* Necessary to update all ancestors when hierarchy is used.
* because their event counter is not touched.
*/
for (; memcg; memcg = parent_mem_cgroup(memcg)) {
mz = mem_cgroup_page_zoneinfo(memcg, page);
excess = soft_limit_excess(memcg);
/*
* We have to update the tree if mz is on RB-tree or
* mem is over its softlimit.
*/
if (excess || mz->on_tree) {
unsigned long flags;
spin_lock_irqsave(&mctz->lock, flags);
/* if on-tree, remove it */
if (mz->on_tree)
__mem_cgroup_remove_exceeded(mz, mctz);
/*
* Insert again. mz->usage_in_excess will be updated.
* If excess is 0, no tree ops.
*/
__mem_cgroup_insert_exceeded(mz, mctz, excess);
spin_unlock_irqrestore(&mctz->lock, flags);
}
}
}
static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
{
struct mem_cgroup_tree_per_zone *mctz;
struct mem_cgroup_per_zone *mz;
int nid, zid;
for_each_node(nid) {
for (zid = 0; zid < MAX_NR_ZONES; zid++) {
mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
mctz = soft_limit_tree_node_zone(nid, zid);
mem_cgroup_remove_exceeded(mz, mctz);
}
}
}
static struct mem_cgroup_per_zone *
__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
{
struct rb_node *rightmost = NULL;
struct mem_cgroup_per_zone *mz;
retry:
mz = NULL;
rightmost = rb_last(&mctz->rb_root);
if (!rightmost)
goto done; /* Nothing to reclaim from */
mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
/*
* Remove the node now but someone else can add it back,
* we will to add it back at the end of reclaim to its correct
* position in the tree.
*/
__mem_cgroup_remove_exceeded(mz, mctz);
if (!soft_limit_excess(mz->memcg) ||
!css_tryget_online(&mz->memcg->css))
goto retry;
done:
return mz;
}
static struct mem_cgroup_per_zone *
mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
{
struct mem_cgroup_per_zone *mz;
spin_lock_irq(&mctz->lock);
mz = __mem_cgroup_largest_soft_limit_node(mctz);
spin_unlock_irq(&mctz->lock);
return mz;
}
/*
* Implementation Note: reading percpu statistics for memcg.
*
* Both of vmstat[] and percpu_counter has threshold and do periodic
* synchronization to implement "quick" read. There are trade-off between
* reading cost and precision of value. Then, we may have a chance to implement
* a periodic synchronizion of counter in memcg's counter.
*
* But this _read() function is used for user interface now. The user accounts
* memory usage by memory cgroup and he _always_ requires exact value because
* he accounts memory. Even if we provide quick-and-fuzzy read, we always
* have to visit all online cpus and make sum. So, for now, unnecessary
* synchronization is not implemented. (just implemented for cpu hotplug)
*
* If there are kernel internal actions which can make use of some not-exact
* value, and reading all cpu value can be performance bottleneck in some
* common workload, threashold and synchonization as vmstat[] should be
* implemented.
*/
static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
enum mem_cgroup_stat_index idx)
{
long val = 0;
int cpu;
get_online_cpus();
for_each_online_cpu(cpu)
val += per_cpu(memcg->stat->count[idx], cpu);
#ifdef CONFIG_HOTPLUG_CPU
spin_lock(&memcg->pcp_counter_lock);
val += memcg->nocpu_base.count[idx];
spin_unlock(&memcg->pcp_counter_lock);
#endif
put_online_cpus();
return val;
}
static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
enum mem_cgroup_events_index idx)
{
unsigned long val = 0;
int cpu;
get_online_cpus();
for_each_online_cpu(cpu)
val += per_cpu(memcg->stat->events[idx], cpu);
#ifdef CONFIG_HOTPLUG_CPU
spin_lock(&memcg->pcp_counter_lock);
val += memcg->nocpu_base.events[idx];
spin_unlock(&memcg->pcp_counter_lock);
#endif
put_online_cpus();
return val;
}
static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
struct page *page,
int nr_pages)
{
/*
* Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
* counted as CACHE even if it's on ANON LRU.
*/
if (PageAnon(page))
__this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS],
nr_pages);
else
__this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE],
nr_pages);
if (PageTransHuge(page))
__this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
nr_pages);
/* pagein of a big page is an event. So, ignore page size */
if (nr_pages > 0)
__this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
else {
__this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
nr_pages = -nr_pages; /* for event */
}
__this_cpu_add(memcg->stat->nr_page_events, nr_pages);
}
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 unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
int nid,
unsigned int lru_mask)
{
unsigned long nr = 0;
int zid;
VM_BUG_ON((unsigned)nid >= nr_node_ids);
for (zid = 0; zid < MAX_NR_ZONES; zid++) {
struct mem_cgroup_per_zone *mz;
enum lru_list lru;
for_each_lru(lru) {
if (!(BIT(lru) & lru_mask))
continue;
mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
nr += mz->lru_size[lru];
}
}
return nr;
}
static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
unsigned int lru_mask)
{
unsigned long nr = 0;
int nid;
for_each_node_state(nid, N_MEMORY)
nr += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask);
return nr;
}
static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
enum mem_cgroup_events_target target)
{
unsigned long val, next;
val = __this_cpu_read(memcg->stat->nr_page_events);
next = __this_cpu_read(memcg->stat->targets[target]);
/* from time_after() in jiffies.h */
if ((long)next - (long)val < 0) {
switch (target) {
case MEM_CGROUP_TARGET_THRESH:
next = val + THRESHOLDS_EVENTS_TARGET;
break;
case MEM_CGROUP_TARGET_SOFTLIMIT:
next = val + SOFTLIMIT_EVENTS_TARGET;
break;
case MEM_CGROUP_TARGET_NUMAINFO:
next = val + NUMAINFO_EVENTS_TARGET;
break;
default:
break;
}
__this_cpu_write(memcg->stat->targets[target], next);
return true;
}
return false;
}
/*
* Check events in order.
*
*/
static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
{
/* threshold event is triggered in finer grain than soft limit */
if (unlikely(mem_cgroup_event_ratelimit(memcg,
MEM_CGROUP_TARGET_THRESH))) {
bool do_softlimit;
bool do_numainfo __maybe_unused;
do_softlimit = mem_cgroup_event_ratelimit(memcg,
MEM_CGROUP_TARGET_SOFTLIMIT);
#if MAX_NUMNODES > 1
do_numainfo = mem_cgroup_event_ratelimit(memcg,
MEM_CGROUP_TARGET_NUMAINFO);
#endif
mem_cgroup_threshold(memcg);
if (unlikely(do_softlimit))
mem_cgroup_update_tree(memcg, page);
#if MAX_NUMNODES > 1
if (unlikely(do_numainfo))
atomic_inc(&memcg->numainfo_events);
#endif
}
}
struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
{
/*
* mm_update_next_owner() may clear mm->owner to NULL
* if it races with swapoff, page migration, etc.
* So this can be called with p == NULL.
*/
if (unlikely(!p))
return NULL;
return mem_cgroup_from_css(task_css(p, memory_cgrp_id));
}
static struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
{
struct mem_cgroup *memcg = NULL;
rcu_read_lock();
do {
/*
* Page cache insertions can happen withou an
* actual mm context, e.g. during disk probing
* on boot, loopback IO, acct() writes etc.
*/
if (unlikely(!mm))
memcg = root_mem_cgroup;
else {
memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
if (unlikely(!memcg))
memcg = root_mem_cgroup;
}
} while (!css_tryget_online(&memcg->css));
rcu_read_unlock();
return memcg;
}
/**
* mem_cgroup_iter - iterate over memory cgroup hierarchy
* @root: hierarchy root
* @prev: previously returned memcg, NULL on first invocation
* @reclaim: cookie for shared reclaim walks, NULL for full walks
*
* Returns references to children of the hierarchy below @root, or
* @root itself, or %NULL after a full round-trip.
*
* Caller must pass the return value in @prev on subsequent
* invocations for reference counting, or use mem_cgroup_iter_break()
* to cancel a hierarchy walk before the round-trip is complete.
*
* Reclaimers can specify a zone and a priority level in @reclaim to
* divide up the memcgs in the hierarchy among all concurrent
* reclaimers operating on the same zone and priority.
*/
struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
struct mem_cgroup *prev,
struct mem_cgroup_reclaim_cookie *reclaim)
{
struct reclaim_iter *uninitialized_var(iter);
struct cgroup_subsys_state *css = NULL;
struct mem_cgroup *memcg = NULL;
struct mem_cgroup *pos = NULL;
if (mem_cgroup_disabled())
return NULL;
if (!root)
root = root_mem_cgroup;
if (prev && !reclaim)
pos = prev;
if (!root->use_hierarchy && root != root_mem_cgroup) {
if (prev)
goto out;
return root;
}
rcu_read_lock();
if (reclaim) {
struct mem_cgroup_per_zone *mz;
mz = mem_cgroup_zone_zoneinfo(root, reclaim->zone);
iter = &mz->iter[reclaim->priority];
if (prev && reclaim->generation != iter->generation)
goto out_unlock;
do {
pos = ACCESS_ONCE(iter->position);
/*
* A racing update may change the position and
* put the last reference, hence css_tryget(),
* or retry to see the updated position.
*/
} while (pos && !css_tryget(&pos->css));
}
if (pos)
css = &pos->css;
for (;;) {
css = css_next_descendant_pre(css, &root->css);
if (!css) {
/*
* Reclaimers share the hierarchy walk, and a
* new one might jump in right at the end of
* the hierarchy - make sure they see at least
* one group and restart from the beginning.
*/
if (!prev)
continue;
break;
}
/*
* Verify the css and acquire a reference. The root
* is provided by the caller, so we know it's alive
* and kicking, and don't take an extra reference.
*/
memcg = mem_cgroup_from_css(css);
if (css == &root->css)
break;
if (css_tryget(css)) {
/*
* Make sure the memcg is initialized:
* mem_cgroup_css_online() orders the the
* initialization against setting the flag.
*/
if (smp_load_acquire(&memcg->initialized))
break;
css_put(css);
}
memcg = NULL;
}
if (reclaim) {
if (cmpxchg(&iter->position, pos, memcg) == pos) {
if (memcg)
css_get(&memcg->css);
if (pos)
css_put(&pos->css);
}
/*
* pairs with css_tryget when dereferencing iter->position
* above.
*/
if (pos)
css_put(&pos->css);
if (!memcg)
iter->generation++;
else if (!prev)
reclaim->generation = iter->generation;
}
out_unlock:
rcu_read_unlock();
out:
if (prev && prev != root)
css_put(&prev->css);
return memcg;
}
/**
* mem_cgroup_iter_break - abort a hierarchy walk prematurely
* @root: hierarchy root
* @prev: last visited hierarchy member as returned by mem_cgroup_iter()
*/
void mem_cgroup_iter_break(struct mem_cgroup *root,
struct mem_cgroup *prev)
{
if (!root)
root = root_mem_cgroup;
if (prev && prev != root)
css_put(&prev->css);
}
/*
* Iteration constructs for visiting all cgroups (under a tree). If
* loops are exited prematurely (break), mem_cgroup_iter_break() must
* be used for reference counting.
*/
#define for_each_mem_cgroup_tree(iter, root) \
for (iter = mem_cgroup_iter(root, NULL, NULL); \
iter != NULL; \
iter = mem_cgroup_iter(root, iter, NULL))
#define for_each_mem_cgroup(iter) \
for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
iter != NULL; \
iter = mem_cgroup_iter(NULL, iter, NULL))
void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
{
struct mem_cgroup *memcg;
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();
}
EXPORT_SYMBOL(__mem_cgroup_count_vm_event);
/**
* mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
* @zone: zone of the wanted lruvec
* @memcg: memcg of the wanted lruvec
*
* Returns the lru list vector holding pages for the given @zone and
* @mem. This can be the global zone lruvec, if the memory controller
* is disabled.
*/
struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
struct mem_cgroup *memcg)
{
struct mem_cgroup_per_zone *mz;
struct lruvec *lruvec;
if (mem_cgroup_disabled()) {
lruvec = &zone->lruvec;
goto out;
}
mz = mem_cgroup_zone_zoneinfo(memcg, zone);
lruvec = &mz->lruvec;
out:
/*
* Since a node can be onlined after the mem_cgroup was created,
* we have to be prepared to initialize lruvec->zone here;
* and if offlined then reonlined, we need to reinitialize it.
*/
if (unlikely(lruvec->zone != zone))
lruvec->zone = zone;
return lruvec;
}
/**
* mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page
* @page: the page
* @zone: zone of the page
*
* This function is only safe when following the LRU page isolation
* and putback protocol: the LRU lock must be held, and the page must
* either be PageLRU() or the caller must have isolated/allocated it.
*/
struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone)
{
struct mem_cgroup_per_zone *mz;
struct mem_cgroup *memcg;
struct lruvec *lruvec;
if (mem_cgroup_disabled()) {
lruvec = &zone->lruvec;
goto out;
}
memcg = page->mem_cgroup;
/*
* Swapcache readahead pages are added to the LRU - and
* possibly migrated - before they are charged.
*/
if (!memcg)
memcg = root_mem_cgroup;
mz = mem_cgroup_page_zoneinfo(memcg, page);
lruvec = &mz->lruvec;
out:
/*
* Since a node can be onlined after the mem_cgroup was created,
* we have to be prepared to initialize lruvec->zone here;
* and if offlined then reonlined, we need to reinitialize it.
*/
if (unlikely(lruvec->zone != zone))
lruvec->zone = zone;
return lruvec;
}
/**
* mem_cgroup_update_lru_size - account for adding or removing an lru page
* @lruvec: mem_cgroup per zone lru vector
* @lru: index of lru list the page is sitting on
* @nr_pages: positive when adding or negative when removing
*
* This function must be called when a page is added to or removed from an
* lru list.
*/
void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
int nr_pages)
{
struct mem_cgroup_per_zone *mz;
unsigned long *lru_size;
if (mem_cgroup_disabled())
return;
mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
lru_size = mz->lru_size + lru;
*lru_size += nr_pages;
VM_BUG_ON((long)(*lru_size) < 0);
}
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);
}
bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg)
{
struct mem_cgroup *task_memcg;
struct task_struct *p;
bool ret;
p = find_lock_task_mm(task);
if (p) {
task_memcg = get_mem_cgroup_from_mm(p->mm);
task_unlock(p);
} else {
/*
* All threads may have already detached their mm's, but the oom
* killer still needs to detect if they have already been oom
* killed to prevent needlessly killing additional tasks.
*/
rcu_read_lock();
task_memcg = mem_cgroup_from_task(task);
css_get(&task_memcg->css);
rcu_read_unlock();
}
ret = mem_cgroup_is_descendant(task_memcg, memcg);
css_put(&task_memcg->css);
return ret;
}
int 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;
}
#define mem_cgroup_from_counter(counter, member) \
container_of(counter, struct mem_cgroup, member)
/**
* mem_cgroup_margin - calculate chargeable space of a memory cgroup
* @memcg: the memory cgroup
*
* Returns the maximum amount of memory @mem can be charged with, in
* pages.
*/
static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
{
unsigned long margin = 0;
unsigned long count;
unsigned long limit;
count = page_counter_read(&memcg->memory);
limit = ACCESS_ONCE(memcg->memory.limit);
if (count < limit)
margin = limit - count;
if (do_swap_account) {
count = page_counter_read(&memcg->memsw);
limit = ACCESS_ONCE(memcg->memsw.limit);
if (count <= limit)
margin = min(margin, limit - count);
}
return margin;
}
int mem_cgroup_swappiness(struct mem_cgroup *memcg)
{
/* root ? */
if (mem_cgroup_disabled() || !memcg->css.parent)
return vm_swappiness;
return memcg->swappiness;
}
/*
* A routine for checking "mem" is under move_account() or not.
*
* Checking a cgroup is mc.from or mc.to or under hierarchy of
* moving cgroups. This is for waiting at high-memory pressure
* caused by "move".
*/
static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
{
struct mem_cgroup *from;
struct mem_cgroup *to;
bool ret = false;
/*
* Unlike task_move routines, we access mc.to, mc.from not under
* mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
*/
spin_lock(&mc.lock);
from = mc.from;
to = mc.to;
if (!from)
goto unlock;
ret = mem_cgroup_is_descendant(from, memcg) ||
mem_cgroup_is_descendant(to, memcg);
unlock:
spin_unlock(&mc.lock);
return ret;
}
static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
{
if (mc.moving_task && current != mc.moving_task) {
if (mem_cgroup_under_move(memcg)) {
DEFINE_WAIT(wait);
prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
/* moving charge context might have finished. */
if (mc.moving_task)
schedule();
finish_wait(&mc.waitq, &wait);
return true;
}
}
return false;
}
#define K(x) ((x) << (PAGE_SHIFT-10))
/**
* mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
* @memcg: The memory cgroup that went over limit
* @p: Task that is going to be killed
*
* NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
* enabled
*/
void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
{
/* oom_info_lock ensures that parallel ooms do not interleave */
static DEFINE_MUTEX(oom_info_lock);
struct mem_cgroup *iter;
unsigned int i;
if (!p)
return;
mutex_lock(&oom_info_lock);
rcu_read_lock();
pr_info("Task in ");
pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
pr_info(" killed as a result of limit of ");
pr_cont_cgroup_path(memcg->css.cgroup);
pr_info("\n");
rcu_read_unlock();
pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
K((u64)page_counter_read(&memcg->memory)),
K((u64)memcg->memory.limit), memcg->memory.failcnt);
pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
K((u64)page_counter_read(&memcg->memsw)),
K((u64)memcg->memsw.limit), memcg->memsw.failcnt);
pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
K((u64)page_counter_read(&memcg->kmem)),
K((u64)memcg->kmem.limit), memcg->kmem.failcnt);
for_each_mem_cgroup_tree(iter, memcg) {
pr_info("Memory cgroup stats for ");
pr_cont_cgroup_path(iter->css.cgroup);
pr_cont(":");
for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
continue;
pr_cont(" %s:%ldKB", mem_cgroup_stat_names[i],
K(mem_cgroup_read_stat(iter, i)));
}
for (i = 0; i < NR_LRU_LISTS; i++)
pr_cont(" %s:%luKB", mem_cgroup_lru_names[i],
K(mem_cgroup_nr_lru_pages(iter, BIT(i))));
pr_cont("\n");
}
mutex_unlock(&oom_info_lock);
}
/*
* This function returns the number of memcg under hierarchy tree. Returns
* 1(self count) if no children.
*/
static int mem_cgroup_count_children(struct mem_cgroup *memcg)
{
int num = 0;
struct mem_cgroup *iter;
for_each_mem_cgroup_tree(iter, memcg)
num++;
return num;
}
/*
* Return the memory (and swap, if configured) limit for a memcg.
*/
static unsigned long mem_cgroup_get_limit(struct mem_cgroup *memcg)
{
unsigned long limit;
limit = memcg->memory.limit;
if (mem_cgroup_swappiness(memcg)) {
unsigned long memsw_limit;
memsw_limit = memcg->memsw.limit;
limit = min(limit + total_swap_pages, memsw_limit);
}
return limit;
}
static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
int order)
{
struct mem_cgroup *iter;
unsigned long chosen_points = 0;
unsigned long totalpages;
unsigned int points = 0;
struct task_struct *chosen = NULL;
/*
* If current has a pending SIGKILL or is exiting, then automatically
* select it. The goal is to allow it to allocate so that it may
* quickly exit and free its memory.
*/
if (fatal_signal_pending(current) || task_will_free_mem(current)) {
set_thread_flag(TIF_MEMDIE);
return;
}
check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL);
totalpages = mem_cgroup_get_limit(memcg) ? : 1;
for_each_mem_cgroup_tree(iter, memcg) {
struct css_task_iter it;
struct task_struct *task;
css_task_iter_start(&iter->css, &it);
while ((task = css_task_iter_next(&it))) {
switch (oom_scan_process_thread(task, totalpages, NULL,
false)) {
case OOM_SCAN_SELECT:
if (chosen)
put_task_struct(chosen);
chosen = task;
chosen_points = ULONG_MAX;
get_task_struct(chosen);
/* fall through */
case OOM_SCAN_CONTINUE:
continue;
case OOM_SCAN_ABORT:
css_task_iter_end(&it);
mem_cgroup_iter_break(memcg, iter);
if (chosen)
put_task_struct(chosen);
return;
case OOM_SCAN_OK:
break;
};
points = oom_badness(task, memcg, NULL, totalpages);
if (!points || points < chosen_points)
continue;
/* Prefer thread group leaders for display purposes */
if (points == chosen_points &&
thread_group_leader(chosen))
continue;
if (chosen)
put_task_struct(chosen);
chosen = task;
chosen_points = points;
get_task_struct(chosen);
}
css_task_iter_end(&it);
}
if (!chosen)
return;
points = chosen_points * 1000 / totalpages;
oom_kill_process(chosen, gfp_mask, order, points, totalpages, memcg,
NULL, "Memory cgroup out of memory");
}
#if MAX_NUMNODES > 1
/**
* test_mem_cgroup_node_reclaimable
* @memcg: the target memcg
* @nid: the node ID to be checked.
* @noswap : specify true here if the user wants flle only information.
*
* This function returns whether the specified memcg contains any
* reclaimable pages on a node. Returns true if there are any reclaimable
* pages in the node.
*/
static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
int nid, bool noswap)
{
if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
return true;
if (noswap || !total_swap_pages)
return false;
if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
return true;
return false;
}
/*
* Always updating the nodemask is not very good - even if we have an empty
* list or the wrong list here, we can start from some node and traverse all
* nodes based on the zonelist. So update the list loosely once per 10 secs.
*
*/
static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
{
int nid;
/*
* numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
* pagein/pageout changes since the last update.
*/
if (!atomic_read(&memcg->numainfo_events))
return;
if (atomic_inc_return(&memcg->numainfo_updating) > 1)
return;
/* make a nodemask where this memcg uses memory from */
memcg->scan_nodes = node_states[N_MEMORY];
for_each_node_mask(nid, node_states[N_MEMORY]) {
if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
node_clear(nid, memcg->scan_nodes);
}
atomic_set(&memcg->numainfo_events, 0);
atomic_set(&memcg->numainfo_updating, 0);
}
/*
* Selecting a node where we start reclaim from. Because what we need is just
* reducing usage counter, start from anywhere is O,K. Considering
* memory reclaim from current node, there are pros. and cons.
*
* Freeing memory from current node means freeing memory from a node which
* we'll use or we've used. So, it may make LRU bad. And if several threads
* hit limits, it will see a contention on a node. But freeing from remote
* node means more costs for memory reclaim because of memory latency.
*
* Now, we use round-robin. Better algorithm is welcomed.
*/
int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
{
int node;
mem_cgroup_may_update_nodemask(memcg);
node = memcg->last_scanned_node;
node = next_node(node, memcg->scan_nodes);
if (node == MAX_NUMNODES)
node = first_node(memcg->scan_nodes);
/*
* We call this when we hit limit, not when pages are added to LRU.
* No LRU may hold pages because all pages are UNEVICTABLE or
* memcg is too small and all pages are not on LRU. In that case,
* we use curret node.
*/
if (unlikely(node == MAX_NUMNODES))
node = numa_node_id();
memcg->last_scanned_node = node;
return node;
}
#else
int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
{
return 0;
}
#endif
static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
struct zone *zone,
gfp_t gfp_mask,
unsigned long *total_scanned)
{
struct mem_cgroup *victim = NULL;
int total = 0;
int loop = 0;
unsigned long excess;
unsigned long nr_scanned;
struct mem_cgroup_reclaim_cookie reclaim = {
.zone = zone,
.priority = 0,
};
excess = soft_limit_excess(root_memcg);
while (1) {
victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
if (!victim) {
loop++;
if (loop >= 2) {
/*
* If we have not been able to reclaim
* anything, it might because there are
* no reclaimable pages under this hierarchy
*/
if (!total)
break;
/*
* We want to do more targeted reclaim.
* excess >> 2 is not to excessive so as to
* reclaim too much, nor too less that we keep
* coming back to reclaim from this cgroup
*/
if (total >= (excess >> 2) ||
(loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
break;
}
continue;
}
total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false,
zone, &nr_scanned);
*total_scanned += nr_scanned;
if (!soft_limit_excess(root_memcg))
break;
}
mem_cgroup_iter_break(root_memcg, victim);
return total;
}
#ifdef CONFIG_LOCKDEP
static struct lockdep_map memcg_oom_lock_dep_map = {
.name = "memcg_oom_lock",
};
#endif
static DEFINE_SPINLOCK(memcg_oom_lock);
/*
* Check OOM-Killer is already running under our hierarchy.
* If someone is running, return false.
*/
static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg)
{
struct mem_cgroup *iter, *failed = NULL;
spin_lock(&memcg_oom_lock);
for_each_mem_cgroup_tree(iter, memcg) {
if (iter->oom_lock) {
/*
* this subtree of our hierarchy is already locked
* so we cannot give a lock.
*/
failed = iter;
mem_cgroup_iter_break(memcg, iter);
break;
} else
iter->oom_lock = true;
}
if (failed) {
/*
* OK, we failed to lock the whole subtree so we have
* to clean up what we set up to the failing subtree
*/
for_each_mem_cgroup_tree(iter, memcg) {
if (iter == failed) {
mem_cgroup_iter_break(memcg, iter);
break;
}
iter->oom_lock = false;
}
} else
mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_);
spin_unlock(&memcg_oom_lock);
return !failed;
}
static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
{
struct mem_cgroup *iter;
spin_lock(&memcg_oom_lock);
mutex_release(&memcg_oom_lock_dep_map, 1, _RET_IP_);
for_each_mem_cgroup_tree(iter, memcg)
iter->oom_lock = false;
spin_unlock(&memcg_oom_lock);
}
static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
{
struct mem_cgroup *iter;
for_each_mem_cgroup_tree(iter, memcg)
atomic_inc(&iter->under_oom);
}
static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
{
struct mem_cgroup *iter;
/*
* When a new child is created while the hierarchy is under oom,
* mem_cgroup_oom_lock() may not be called. We have to use
* atomic_add_unless() here.
*/
for_each_mem_cgroup_tree(iter, memcg)
atomic_add_unless(&iter->under_oom, -1, 0);
}
static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
struct oom_wait_info {
struct mem_cgroup *memcg;
wait_queue_t wait;
};
static int memcg_oom_wake_function(wait_queue_t *wait,
unsigned mode, int sync, void *arg)
{
struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
struct mem_cgroup *oom_wait_memcg;
struct oom_wait_info *oom_wait_info;
oom_wait_info = container_of(wait, struct oom_wait_info, wait);
oom_wait_memcg = oom_wait_info->memcg;
if (!mem_cgroup_is_descendant(wake_memcg, oom_wait_memcg) &&
!mem_cgroup_is_descendant(oom_wait_memcg, wake_memcg))
return 0;
return autoremove_wake_function(wait, mode, sync, arg);
}
static void memcg_wakeup_oom(struct mem_cgroup *memcg)
{
atomic_inc(&memcg->oom_wakeups);
/* for filtering, pass "memcg" as argument. */
__wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
}
static void memcg_oom_recover(struct mem_cgroup *memcg)
{
if (memcg && atomic_read(&memcg->under_oom))
memcg_wakeup_oom(memcg);
}
static void mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
{
if (!current->memcg_oom.may_oom)
return;
/*
* We are in the middle of the charge context here, so we
* don't want to block when potentially sitting on a callstack
* that holds all kinds of filesystem and mm locks.
*
* Also, the caller may handle a failed allocation gracefully
* (like optional page cache readahead) and so an OOM killer
* invocation might not even be necessary.
*
* That's why we don't do anything here except remember the
* OOM context and then deal with it at the end of the page
* fault when the stack is unwound, the locks are released,
* and when we know whether the fault was overall successful.
*/
css_get(&memcg->css);
current->memcg_oom.memcg = memcg;
current->memcg_oom.gfp_mask = mask;
current->memcg_oom.order = order;
}
/**
* mem_cgroup_oom_synchronize - complete memcg OOM handling
* @handle: actually kill/wait or just clean up the OOM state
*
* This has to be called at the end of a page fault if the memcg OOM
* handler was enabled.
*
* Memcg supports userspace OOM handling where failed allocations must
* sleep on a waitqueue until the userspace task resolves the
* situation. Sleeping directly in the charge context with all kinds
* of locks held is not a good idea, instead we remember an OOM state
* in the task and mem_cgroup_oom_synchronize() has to be called at
* the end of the page fault to complete the OOM handling.
*
* Returns %true if an ongoing memcg OOM situation was detected and
* completed, %false otherwise.
*/
bool mem_cgroup_oom_synchronize(bool handle)
{
struct mem_cgroup *memcg = current->memcg_oom.memcg;
struct oom_wait_info owait;
bool locked;
/* OOM is global, do not handle */
if (!memcg)
return false;
if (!handle)
goto cleanup;
owait.memcg = memcg;
owait.wait.flags = 0;
owait.wait.func = memcg_oom_wake_function;
owait.wait.private = current;
INIT_LIST_HEAD(&owait.wait.task_list);
prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
mem_cgroup_mark_under_oom(memcg);
locked = mem_cgroup_oom_trylock(memcg);
if (locked)
mem_cgroup_oom_notify(memcg);
if (locked && !memcg->oom_kill_disable) {
mem_cgroup_unmark_under_oom(memcg);
finish_wait(&memcg_oom_waitq, &owait.wait);
mem_cgroup_out_of_memory(memcg, current->memcg_oom.gfp_mask,
current->memcg_oom.order);
} else {
schedule();
mem_cgroup_unmark_under_oom(memcg);
finish_wait(&memcg_oom_waitq, &owait.wait);
}
if (locked) {
mem_cgroup_oom_unlock(memcg);
/*
* There is no guarantee that an OOM-lock contender
* sees the wakeups triggered by the OOM kill
* uncharges. Wake any sleepers explicitely.
*/
memcg_oom_recover(memcg);
}
cleanup:
current->memcg_oom.memcg = NULL;
css_put(&memcg->css);
return true;
}
/**
* mem_cgroup_begin_page_stat - begin a page state statistics transaction
* @page: page that is going to change accounted state
* @locked: &memcg->move_lock slowpath was taken
* @flags: IRQ-state flags for &memcg->move_lock
*
* This function must mark the beginning of an accounted page state
* change to prevent double accounting when the page is concurrently
* being moved to another memcg:
*
* memcg = mem_cgroup_begin_page_stat(page, &locked, &flags);
* if (TestClearPageState(page))
* mem_cgroup_update_page_stat(memcg, state, -1);
* mem_cgroup_end_page_stat(memcg, locked, flags);
*
* The RCU lock is held throughout the transaction. The fast path can
* get away without acquiring the memcg->move_lock (@locked is false)
* because page moving starts with an RCU grace period.
*
* The RCU lock also protects the memcg from being freed when the page
* state that is going to change is the only thing preventing the page
* from being uncharged. E.g. end-writeback clearing PageWriteback(),
* which allows migration to go ahead and uncharge the page before the
* account transaction might be complete.
*/
struct mem_cgroup *mem_cgroup_begin_page_stat(struct page *page,
bool *locked,
unsigned long *flags)
{
struct mem_cgroup *memcg;
rcu_read_lock();
if (mem_cgroup_disabled())
return NULL;
again:
memcg = page->mem_cgroup;
if (unlikely(!memcg))
return NULL;
*locked = false;
if (atomic_read(&memcg->moving_account) <= 0)
return memcg;
spin_lock_irqsave(&memcg->move_lock, *flags);
if (memcg != page->mem_cgroup) {
spin_unlock_irqrestore(&memcg->move_lock, *flags);
goto again;
}
*locked = true;
return memcg;
}
/**
* mem_cgroup_end_page_stat - finish a page state statistics transaction
* @memcg: the memcg that was accounted against
* @locked: value received from mem_cgroup_begin_page_stat()
* @flags: value received from mem_cgroup_begin_page_stat()
*/
void mem_cgroup_end_page_stat(struct mem_cgroup *memcg, bool *locked,
unsigned long *flags)
{
if (memcg && *locked)
spin_unlock_irqrestore(&memcg->move_lock, *flags);
rcu_read_unlock();
}
/**
* 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.
*/
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);
}
/*
* size of first charge trial. "32" comes from vmscan.c's magic value.
* TODO: maybe necessary to use big numbers in big irons.
*/
#define CHARGE_BATCH 32U
struct memcg_stock_pcp {
struct mem_cgroup *cached; /* this never be root cgroup */
unsigned int nr_pages;
struct work_struct work;
unsigned long flags;
#define FLUSHING_CACHED_CHARGE 0
};
static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
static DEFINE_MUTEX(percpu_charge_mutex);
/**
* consume_stock: Try to consume stocked charge on this cpu.
* @memcg: memcg to consume from.
* @nr_pages: how many pages to charge.
*
* The charges will only happen if @memcg matches the current cpu's memcg
* stock, and at least @nr_pages are available in that stock. Failure to
* service an allocation will refill the stock.
*
* returns true if successful, false otherwise.
*/
static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
{
struct memcg_stock_pcp *stock;
bool ret = false;
if (nr_pages > CHARGE_BATCH)
return ret;
stock = &get_cpu_var(memcg_stock);
if (memcg == stock->cached && stock->nr_pages >= nr_pages) {
stock->nr_pages -= nr_pages;
ret = true;
}
put_cpu_var(memcg_stock);
return ret;
}
/*
* Returns stocks cached in percpu and reset cached information.
*/
static void drain_stock(struct memcg_stock_pcp *stock)
{
struct mem_cgroup *old = stock->cached;
if (stock->nr_pages) {
page_counter_uncharge(&old->memory, stock->nr_pages);
if (do_swap_account)
page_counter_uncharge(&old->memsw, stock->nr_pages);
css_put_many(&old->css, stock->nr_pages);
stock->nr_pages = 0;
}
stock->cached = NULL;
}
/*
* This must be called under preempt disabled or must be called by
* a thread which is pinned to local cpu.
*/
static void drain_local_stock(struct work_struct *dummy)
{
struct memcg_stock_pcp *stock = this_cpu_ptr(&memcg_stock);
drain_stock(stock);
clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
}
static void __init memcg_stock_init(void)
{
int cpu;
for_each_possible_cpu(cpu) {
struct memcg_stock_pcp *stock =
&per_cpu(memcg_stock, cpu);
INIT_WORK(&stock->work, drain_local_stock);
}
}
/*
* Cache charges(val) to local per_cpu area.
* This will be consumed by consume_stock() function, later.
*/
static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
{
struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
if (stock->cached != memcg) { /* reset if necessary */
drain_stock(stock);
stock->cached = memcg;
}
stock->nr_pages += nr_pages;
put_cpu_var(memcg_stock);
}
/*
* Drains all per-CPU charge caches for given root_memcg resp. subtree
* of the hierarchy under it.
*/
static void drain_all_stock(struct mem_cgroup *root_memcg)
{
int cpu, curcpu;
/* If someone's already draining, avoid adding running more workers. */
if (!mutex_trylock(&percpu_charge_mutex))
return;
/* Notify other cpus that system-wide "drain" is running */
get_online_cpus();
curcpu = get_cpu();
for_each_online_cpu(cpu) {
struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
struct mem_cgroup *memcg;
memcg = stock->cached;
if (!memcg || !stock->nr_pages)
continue;
if (!mem_cgroup_is_descendant(memcg, root_memcg))
continue;
if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
if (cpu == curcpu)
drain_local_stock(&stock->work);
else
schedule_work_on(cpu, &stock->work);
}
}
put_cpu();
put_online_cpus();
mutex_unlock(&percpu_charge_mutex);
}
/*
* This function drains percpu counter value from DEAD cpu and
* move it to local cpu. Note that this function can be preempted.
*/
static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu)
{
int i;
spin_lock(&memcg->pcp_counter_lock);
for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
long x = per_cpu(memcg->stat->count[i], cpu);
per_cpu(memcg->stat->count[i], cpu) = 0;
memcg->nocpu_base.count[i] += x;
}
for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
unsigned long x = per_cpu(memcg->stat->events[i], cpu);
per_cpu(memcg->stat->events[i], cpu) = 0;
memcg->nocpu_base.events[i] += x;
}
spin_unlock(&memcg->pcp_counter_lock);
}
static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
unsigned long action,
void *hcpu)
{
int cpu = (unsigned long)hcpu;
struct memcg_stock_pcp *stock;
struct mem_cgroup *iter;
if (action == CPU_ONLINE)
return NOTIFY_OK;
if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
return NOTIFY_OK;
for_each_mem_cgroup(iter)
mem_cgroup_drain_pcp_counter(iter, cpu);
stock = &per_cpu(memcg_stock, cpu);
drain_stock(stock);
return NOTIFY_OK;
}
static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
unsigned int nr_pages)
{
unsigned int batch = max(CHARGE_BATCH, nr_pages);
int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
struct mem_cgroup *mem_over_limit;
struct page_counter *counter;
unsigned long nr_reclaimed;
bool may_swap = true;
bool drained = false;
int ret = 0;
if (mem_cgroup_is_root(memcg))
goto done;
retry:
if (consume_stock(memcg, nr_pages))
goto done;
if (!do_swap_account ||
!page_counter_try_charge(&memcg->memsw, batch, &counter)) {
if (!page_counter_try_charge(&memcg->memory, batch, &counter))
goto done_restock;
if (do_swap_account)
page_counter_uncharge(&memcg->memsw, batch);
mem_over_limit = mem_cgroup_from_counter(counter, memory);
} else {
mem_over_limit = mem_cgroup_from_counter(counter, memsw);
may_swap = false;
}
if (batch > nr_pages) {
batch = nr_pages;
goto retry;
}
/*
* Unlike in global OOM situations, memcg is not in a physical
* memory shortage. Allow dying and OOM-killed tasks to
* bypass the last charges so that they can exit quickly and
* free their memory.
*/
if (unlikely(test_thread_flag(TIF_MEMDIE) ||
fatal_signal_pending(current) ||
current->flags & PF_EXITING))
goto bypass;
if (unlikely(task_in_memcg_oom(current)))
goto nomem;
if (!(gfp_mask & __GFP_WAIT))
goto nomem;
nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages,
gfp_mask, may_swap);
if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
goto retry;
if (!drained) {
drain_all_stock(mem_over_limit);
drained = true;
goto retry;
}
if (gfp_mask & __GFP_NORETRY)
goto nomem;
/*
* Even though the limit is exceeded at this point, reclaim
* may have been able to free some pages. Retry the charge
* before killing the task.
*
* Only for regular pages, though: huge pages are rather
* unlikely to succeed so close to the limit, and we fall back
* to regular pages anyway in case of failure.
*/
if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER))
goto retry;
/*
* At task move, charge accounts can be doubly counted. So, it's
* better to wait until the end of task_move if something is going on.
*/
if (mem_cgroup_wait_acct_move(mem_over_limit))
goto retry;
if (nr_retries--)
goto retry;
if (gfp_mask & __GFP_NOFAIL)
goto bypass;
if (fatal_signal_pending(current))
goto bypass;
mem_cgroup_oom(mem_over_limit, gfp_mask, get_order(nr_pages));
nomem:
if (!(gfp_mask & __GFP_NOFAIL))
return -ENOMEM;
bypass:
return -EINTR;
done_restock:
css_get_many(&memcg->css, batch);
if (batch > nr_pages)
refill_stock(memcg, batch - nr_pages);
done:
return ret;
}
static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
{
if (mem_cgroup_is_root(memcg))
return;
page_counter_uncharge(&memcg->memory, nr_pages);
if (do_swap_account)
page_counter_uncharge(&memcg->memsw, nr_pages);
css_put_many(&memcg->css, nr_pages);
}
/*
* A helper function to get mem_cgroup from ID. must be called under
* rcu_read_lock(). The caller is responsible for calling
* css_tryget_online() if the mem_cgroup is used for charging. (dropping
* refcnt from swap can be called against removed memcg.)
*/
static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
{
/* ID 0 is unused ID */
if (!id)
return NULL;
return mem_cgroup_from_id(id);
}
/*
* try_get_mem_cgroup_from_page - look up page's memcg association
* @page: the page
*
* Look up, get a css reference, and return the memcg that owns @page.
*
* The page must be locked to prevent racing with swap-in and page
* cache charges. If coming from an unlocked page table, the caller
* must ensure the page is on the LRU or this can race with charging.
*/
struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
{
struct mem_cgroup *memcg;
unsigned short id;
swp_entry_t ent;
VM_BUG_ON_PAGE(!PageLocked(page), page);
memcg = page->mem_cgroup;
if (memcg) {
if (!css_tryget_online(&memcg->css))
memcg = NULL;
} else if (PageSwapCache(page)) {
ent.val = page_private(page);
id = lookup_swap_cgroup_id(ent);
rcu_read_lock();
memcg = mem_cgroup_lookup(id);
if (memcg && !css_tryget_online(&memcg->css))
memcg = NULL;
rcu_read_unlock();
}
return memcg;
}
static void lock_page_lru(struct page *page, int *isolated)
{
struct zone *zone = page_zone(page);
spin_lock_irq(&zone->lru_lock);
if (PageLRU(page)) {
struct lruvec *lruvec;
lruvec = mem_cgroup_page_lruvec(page, zone);
ClearPageLRU(page);
del_page_from_lru_list(page, lruvec, page_lru(page));
*isolated = 1;
} else
*isolated = 0;
}
static void unlock_page_lru(struct page *page, int isolated)
{
struct zone *zone = page_zone(page);
if (isolated) {
struct lruvec *lruvec;
lruvec = mem_cgroup_page_lruvec(page, zone);
VM_BUG_ON_PAGE(PageLRU(page), page);
SetPageLRU(page);
add_page_to_lru_list(page, lruvec, page_lru(page));
}
spin_unlock_irq(&zone->lru_lock);
}
static void commit_charge(struct page *page, struct mem_cgroup *memcg,
bool lrucare)
{
int isolated;
VM_BUG_ON_PAGE(page->mem_cgroup, page);
/*
* In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
* may already be on some other mem_cgroup's LRU. Take care of it.
*/
if (lrucare)
lock_page_lru(page, &isolated);
/*
* Nobody should be changing or seriously looking at
* page->mem_cgroup at this point:
*
* - the page is uncharged
*
* - the page is off-LRU
*
* - an anonymous fault has exclusive page access, except for
* a locked page table
*
* - a page cache insertion, a swapin fault, or a migration
* have the page locked
*/
page->mem_cgroup = memcg;
if (lrucare)
unlock_page_lru(page, isolated);
}
#ifdef CONFIG_MEMCG_KMEM
/*
* The memcg_slab_mutex is held whenever a per memcg kmem cache is created or
* destroyed. It protects memcg_caches arrays and memcg_slab_caches lists.
*/
static DEFINE_MUTEX(memcg_slab_mutex);
/*
* This is a bit cumbersome, but it is rarely used and avoids a backpointer
* in the memcg_cache_params struct.
*/
static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p)
{
struct kmem_cache *cachep;
VM_BUG_ON(p->is_root_cache);
cachep = p->root_cache;
return cache_from_memcg_idx(cachep, memcg_cache_id(p->memcg));
}
static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp,
unsigned long nr_pages)
{
struct page_counter *counter;
int ret = 0;
ret = page_counter_try_charge(&memcg->kmem, nr_pages, &counter);
if (ret < 0)
return ret;
ret = try_charge(memcg, gfp, nr_pages);
if (ret == -EINTR) {
/*
* try_charge() chose to bypass to root due to OOM kill or
* fatal signal. Since our only options are to either fail
* the allocation or charge it to this cgroup, do it as a
* temporary condition. But we can't fail. From a kmem/slab
* perspective, the cache has already been selected, by
* mem_cgroup_kmem_get_cache(), so it is too late to change
* our minds.
*
* This condition will only trigger if the task entered
* memcg_charge_kmem in a sane state, but was OOM-killed
* during try_charge() above. Tasks that were already dying
* when the allocation triggers should have been already
* directed to the root cgroup in memcontrol.h
*/
page_counter_charge(&memcg->memory, nr_pages);
if (do_swap_account)
page_counter_charge(&memcg->memsw, nr_pages);
css_get_many(&memcg->css, nr_pages);
ret = 0;
} else if (ret)
page_counter_uncharge(&memcg->kmem, nr_pages);
return ret;
}
static void memcg_uncharge_kmem(struct mem_cgroup *memcg,
unsigned long nr_pages)
{
page_counter_uncharge(&memcg->memory, nr_pages);
if (do_swap_account)
page_counter_uncharge(&memcg->memsw, nr_pages);
page_counter_uncharge(&memcg->kmem, nr_pages);
css_put_many(&memcg->css, nr_pages);
}
/*
* 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.
*/
int memcg_cache_id(struct mem_cgroup *memcg)
{
return memcg ? memcg->kmemcg_id : -1;
}
static int memcg_alloc_cache_id(void)
{
int id, size;
int err;
id = ida_simple_get(&kmem_limited_groups,
0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
if (id < 0)
return id;
if (id < memcg_limited_groups_array_size)
return id;
/*
* There's no space for the new id in memcg_caches arrays,
* so we have to grow them.
*/
size = 2 * (id + 1);
if (size < MEMCG_CACHES_MIN_SIZE)
size = MEMCG_CACHES_MIN_SIZE;
else if (size > MEMCG_CACHES_MAX_SIZE)
size = MEMCG_CACHES_MAX_SIZE;
mutex_lock(&memcg_slab_mutex);
err = memcg_update_all_caches(size);
mutex_unlock(&memcg_slab_mutex);
if (err) {
ida_simple_remove(&kmem_limited_groups, id);
return err;
}
return id;
}
static void memcg_free_cache_id(int id)
{
ida_simple_remove(&kmem_limited_groups, id);
}
/*
* We should update the current array size iff all caches updates succeed. This
* can only be done from the slab side. The slab mutex needs to be held when
* calling this.
*/
void memcg_update_array_size(int num)
{
memcg_limited_groups_array_size = num;
}
static void memcg_register_cache(struct mem_cgroup *memcg,
struct kmem_cache *root_cache)
{
static char memcg_name_buf[NAME_MAX + 1]; /* protected by
memcg_slab_mutex */
struct kmem_cache *cachep;
int id;
lockdep_assert_held(&memcg_slab_mutex);
id = memcg_cache_id(memcg);
/*
* Since per-memcg caches are created asynchronously on first
* allocation (see memcg_kmem_get_cache()), several threads can try to
* create the same cache, but only one of them may succeed.
*/
if (cache_from_memcg_idx(root_cache, id))
return;
cgroup_name(memcg->css.cgroup, memcg_name_buf, NAME_MAX + 1);
cachep = memcg_create_kmem_cache(memcg, root_cache, memcg_name_buf);
/*
* If we could not create a memcg cache, do not complain, because
* that's not critical at all as we can always proceed with the root
* cache.
*/
if (!cachep)
return;
list_add(&cachep->memcg_params->list, &memcg->memcg_slab_caches);
/*
* Since readers won't lock (see cache_from_memcg_idx()), we need a
* barrier here to ensure nobody will see the kmem_cache partially
* initialized.
*/
smp_wmb();
BUG_ON(root_cache->memcg_params->memcg_caches[id]);
root_cache->memcg_params->memcg_caches[id] = cachep;
}
static void memcg_unregister_cache(struct kmem_cache *cachep)
{
struct kmem_cache *root_cache;
struct mem_cgroup *memcg;
int id;
lockdep_assert_held(&memcg_slab_mutex);
BUG_ON(is_root_cache(cachep));
root_cache = cachep->memcg_params->root_cache;
memcg = cachep->memcg_params->memcg;
id = memcg_cache_id(memcg);
BUG_ON(root_cache->memcg_params->memcg_caches[id] != cachep);
root_cache->memcg_params->memcg_caches[id] = NULL;
list_del(&cachep->memcg_params->list);
kmem_cache_destroy(cachep);
}
int __memcg_cleanup_cache_params(struct kmem_cache *s)
{
struct kmem_cache *c;
int i, failed = 0;
mutex_lock(&memcg_slab_mutex);
for_each_memcg_cache_index(i) {
c = cache_from_memcg_idx(s, i);
if (!c)
continue;
memcg_unregister_cache(c);
if (cache_from_memcg_idx(s, i))
failed++;
}
mutex_unlock(&memcg_slab_mutex);
return failed;
}
static void memcg_unregister_all_caches(struct mem_cgroup *memcg)
{
struct kmem_cache *cachep;
struct memcg_cache_params *params, *tmp;
if (!memcg_kmem_is_active(memcg))
return;
mutex_lock(&memcg_slab_mutex);
list_for_each_entry_safe(params, tmp, &memcg->memcg_slab_caches, list) {
cachep = memcg_params_to_cache(params);
memcg_unregister_cache(cachep);
}
mutex_unlock(&memcg_slab_mutex);
}
struct memcg_register_cache_work {
struct mem_cgroup *memcg;
struct kmem_cache *cachep;
struct work_struct work;
};
static void memcg_register_cache_func(struct work_struct *w)
{
struct memcg_register_cache_work *cw =
container_of(w, struct memcg_register_cache_work, work);
struct mem_cgroup *memcg = cw->memcg;
struct kmem_cache *cachep = cw->cachep;
mutex_lock(&memcg_slab_mutex);
memcg_register_cache(memcg, cachep);
mutex_unlock(&memcg_slab_mutex);
css_put(&memcg->css);
kfree(cw);
}
/*
* Enqueue the creation of a per-memcg kmem_cache.
*/
static void __memcg_schedule_register_cache(struct mem_cgroup *memcg,
struct kmem_cache *cachep)
{
struct memcg_register_cache_work *cw;
cw = kmalloc(sizeof(*cw), GFP_NOWAIT);
if (!cw)
return;
css_get(&memcg->css);
cw->memcg = memcg;
cw->cachep = cachep;
INIT_WORK(&cw->work, memcg_register_cache_func);
schedule_work(&cw->work);
}
static void memcg_schedule_register_cache(struct mem_cgroup *memcg,
struct kmem_cache *cachep)
{
/*
* We need to stop accounting when we kmalloc, because if the
* corresponding kmalloc cache is not yet created, the first allocation
* in __memcg_schedule_register_cache will recurse.
*
* However, it is better to enclose the whole function. Depending on
* the debugging options enabled, INIT_WORK(), for instance, can
* trigger an allocation. This too, will make us recurse. Because at
* this point we can't allow ourselves back into memcg_kmem_get_cache,
* the safest choice is to do it like this, wrapping the whole function.
*/
current->memcg_kmem_skip_account = 1;
__memcg_schedule_register_cache(memcg, cachep);
current->memcg_kmem_skip_account = 0;
}
int __memcg_charge_slab(struct kmem_cache *cachep, gfp_t gfp, int order)
{
unsigned int nr_pages = 1 << order;
return memcg_charge_kmem(cachep->memcg_params->memcg, gfp, nr_pages);
}
void __memcg_uncharge_slab(struct kmem_cache *cachep, int order)
{
unsigned int nr_pages = 1 << order;
memcg_uncharge_kmem(cachep->memcg_params->memcg, nr_pages);
}
/*
* Return the kmem_cache we're supposed to use for a slab allocation.
* We try to use the current memcg's version of the cache.
*
* If the cache does not exist yet, if we are the first user of it,
* we either create it immediately, if possible, or create it asynchronously
* in a workqueue.
* In the latter case, we will let the current allocation go through with
* the original cache.
*
* Can't be called in interrupt context or from kernel threads.
* This function needs to be called with rcu_read_lock() held.
*/
struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep)
{
struct mem_cgroup *memcg;
struct kmem_cache *memcg_cachep;
VM_BUG_ON(!cachep->memcg_params);
VM_BUG_ON(!cachep->memcg_params->is_root_cache);
if (current->memcg_kmem_skip_account)
return cachep;
memcg = get_mem_cgroup_from_mm(current->mm);
if (!memcg_kmem_is_active(memcg))
goto out;
memcg_cachep = cache_from_memcg_idx(cachep, memcg_cache_id(memcg));
if (likely(memcg_cachep))
return memcg_cachep;
/*
* If we are in a safe context (can wait, and not in interrupt
* context), we could be be predictable and return right away.
* This would guarantee that the allocation being performed
* already belongs in the new cache.
*
* However, there are some clashes that can arrive from locking.
* For instance, because we acquire the slab_mutex while doing
* memcg_create_kmem_cache, this means no further allocation
* could happen with the slab_mutex held. So it's better to
* defer everything.
*/
memcg_schedule_register_cache(memcg, cachep);
out:
css_put(&memcg->css);
return cachep;
}
void __memcg_kmem_put_cache(struct kmem_cache *cachep)
{
if (!is_root_cache(cachep))
css_put(&cachep->memcg_params->memcg->css);
}
/*
* We need to verify if the allocation against current->mm->owner's memcg is
* possible for the given order. But the page is not allocated yet, so we'll
* need a further commit step to do the final arrangements.
*
* It is possible for the task to switch cgroups in this mean time, so at
* commit time, we can't rely on task conversion any longer. We'll then use
* the handle argument to return to the caller which cgroup we should commit
* against. We could also return the memcg directly and avoid the pointer
* passing, but a boolean return value gives better semantics considering
* the compiled-out case as well.
*
* Returning true means the allocation is possible.
*/
bool
__memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order)
{
struct mem_cgroup *memcg;
int ret;
*_memcg = NULL;
memcg = get_mem_cgroup_from_mm(current->mm);
if (!memcg_kmem_is_active(memcg)) {
css_put(&memcg->css);
return true;
}
ret = memcg_charge_kmem(memcg, gfp, 1 << order);
if (!ret)
*_memcg = memcg;
css_put(&memcg->css);
return (ret == 0);
}
void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg,
int order)
{
VM_BUG_ON(mem_cgroup_is_root(memcg));
/* The page allocation failed. Revert */
if (!page) {
memcg_uncharge_kmem(memcg, 1 << order);
return;
}
page->mem_cgroup = memcg;
}
void __memcg_kmem_uncharge_pages(struct page *page, int order)
{
struct mem_cgroup *memcg = page->mem_cgroup;
if (!memcg)
return;
VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page);
memcg_uncharge_kmem(memcg, 1 << order);
page->mem_cgroup = NULL;
}
#endif /* CONFIG_MEMCG_KMEM */
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/*
* Because tail pages are not marked as "used", set it. We're under
* zone->lru_lock, 'splitting on pmd' and compound_lock.
* charge/uncharge will be never happen and move_account() is done under
* compound_lock(), so we don't have to take care of races.
*/
void mem_cgroup_split_huge_fixup(struct page *head)
{
int i;
if (mem_cgroup_disabled())
return;
for (i = 1; i < HPAGE_PMD_NR; i++)
head[i].mem_cgroup = head->mem_cgroup;
__this_cpu_sub(head->mem_cgroup->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
HPAGE_PMD_NR);
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
/**
* mem_cgroup_move_account - move account of the page
* @page: the page
* @nr_pages: number of regular pages (>1 for huge pages)
* @from: mem_cgroup which the page is moved from.
* @to: mem_cgroup which the page is moved to. @from != @to.
*
* The caller must confirm following.
* - page is not on LRU (isolate_page() is useful.)
* - compound_lock is held when nr_pages > 1
*
* This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
* from old cgroup.
*/
static int mem_cgroup_move_account(struct page *page,
unsigned int nr_pages,
struct mem_cgroup *from,
struct mem_cgroup *to)
{
unsigned long flags;
int ret;
VM_BUG_ON(from == to);
VM_BUG_ON_PAGE(PageLRU(page), page);
/*
* The page is isolated from LRU. So, collapse function
* will not handle this page. But page splitting can happen.
* Do this check under compound_page_lock(). The caller should
* hold it.
*/
ret = -EBUSY;
if (nr_pages > 1 && !PageTransHuge(page))
goto out;
/*
* Prevent mem_cgroup_migrate() from looking at page->mem_cgroup
* of its source page while we change it: page migration takes
* both pages off the LRU, but page cache replacement doesn't.
*/
if (!trylock_page(page))
goto out;
ret = -EINVAL;
if (page->mem_cgroup != from)
goto out_unlock;
spin_lock_irqsave(&from->move_lock, flags);
if (!PageAnon(page) && page_mapped(page)) {
__this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
nr_pages);
__this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
nr_pages);
}
if (PageWriteback(page)) {
__this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK],
nr_pages);
__this_cpu_add(to->stat->count[MEM_CGROUP_STAT_WRITEBACK],
nr_pages);
}
/*
* It is safe to change page->mem_cgroup here because the page
* is referenced, charged, and isolated - we can't race with
* uncharging, charging, migration, or LRU putback.
*/
/* caller should have done css_get */
page->mem_cgroup = to;
spin_unlock_irqrestore(&from->move_lock, flags);
ret = 0;
local_irq_disable();
mem_cgroup_charge_statistics(to, page, nr_pages);
memcg_check_events(to, page);
mem_cgroup_charge_statistics(from, page, -nr_pages);
memcg_check_events(from, page);
local_irq_enable();
out_unlock:
unlock_page(page);
out:
return ret;
}
#ifdef CONFIG_MEMCG_SWAP
static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
bool charge)
{
int val = (charge) ? 1 : -1;
this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val);
}
/**
* mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
* @entry: swap entry to be moved
* @from: mem_cgroup which the entry is moved from
* @to: mem_cgroup which the entry is moved to
*
* It succeeds only when the swap_cgroup's record for this entry is the same
* as the mem_cgroup's id of @from.
*
* Returns 0 on success, -EINVAL on failure.
*
* The caller must have charged to @to, IOW, called page_counter_charge() about
* both res and memsw, and called css_get().
*/
static int mem_cgroup_move_swap_account(swp_entry_t entry,
struct mem_cgroup *from, struct mem_cgroup *to)
{
unsigned short old_id, new_id;
old_id = mem_cgroup_id(from);
new_id = mem_cgroup_id(to);
if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
mem_cgroup_swap_statistics(from, false);
mem_cgroup_swap_statistics(to, true);
/*
* This function is only called from task migration context now.
* It postpones page_counter and refcount handling till the end
* of task migration(mem_cgroup_clear_mc()) for performance
* improvement. But we cannot postpone css_get(to) because if
* the process that has been moved to @to does swap-in, the
* refcount of @to might be decreased to 0.
*
* We are in attach() phase, so the cgroup is guaranteed to be
* alive, so we can just call css_get().
*/
css_get(&to->css);
return 0;
}
return -EINVAL;
}
#else
static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
struct mem_cgroup *from, struct mem_cgroup *to)
{
return -EINVAL;
}
#endif
static DEFINE_MUTEX(memcg_limit_mutex);
static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
unsigned long limit)
{
unsigned long curusage;
unsigned long oldusage;
bool enlarge = false;
int retry_count;
int ret;
/*
* For keeping hierarchical_reclaim simple, how long we should retry
* is depends on callers. We set our retry-count to be function
* of # of children which we should visit in this loop.
*/
retry_count = MEM_CGROUP_RECLAIM_RETRIES *
mem_cgroup_count_children(memcg);
oldusage = page_counter_read(&memcg->memory);
do {
if (signal_pending(current)) {
ret = -EINTR;
break;
}
mutex_lock(&memcg_limit_mutex);
if (limit > memcg->memsw.limit) {
mutex_unlock(&memcg_limit_mutex);
ret = -EINVAL;
break;
}
if (limit > memcg->memory.limit)
enlarge = true;
ret = page_counter_limit(&memcg->memory, limit);
mutex_unlock(&memcg_limit_mutex);
if (!ret)
break;
try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, true);
curusage = page_counter_read(&memcg->memory);
/* Usage is reduced ? */
if (curusage >= oldusage)
retry_count--;
else
oldusage = curusage;
} while (retry_count);
if (!ret && enlarge)
memcg_oom_recover(memcg);
return ret;
}
static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
unsigned long limit)
{
unsigned long curusage;
unsigned long oldusage;
bool enlarge = false;
int retry_count;
int ret;
/* see mem_cgroup_resize_res_limit */
retry_count = MEM_CGROUP_RECLAIM_RETRIES *
mem_cgroup_count_children(memcg);
oldusage = page_counter_read(&memcg->memsw);
do {
if (signal_pending(current)) {
ret = -EINTR;
break;
}
mutex_lock(&memcg_limit_mutex);
if (limit < memcg->memory.limit) {
mutex_unlock(&memcg_limit_mutex);
ret = -EINVAL;
break;
}
if (limit > memcg->memsw.limit)
enlarge = true;
ret = page_counter_limit(&memcg->memsw, limit);
mutex_unlock(&memcg_limit_mutex);
if (!ret)
break;
try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, false);
curusage = page_counter_read(&memcg->memsw);
/* Usage is reduced ? */
if (curusage >= oldusage)
retry_count--;
else
oldusage = curusage;
} while (retry_count);
if (!ret && enlarge)
memcg_oom_recover(memcg);
return ret;
}
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
gfp_t gfp_mask,
unsigned long *total_scanned)
{
unsigned long nr_reclaimed = 0;
struct mem_cgroup_per_zone *mz, *next_mz = NULL;
unsigned long reclaimed;
int loop = 0;
struct mem_cgroup_tree_per_zone *mctz;
unsigned long excess;
unsigned long nr_scanned;
if (order > 0)
return 0;
mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
/*
* This loop can run a while, specially if mem_cgroup's continuously
* keep exceeding their soft limit and putting the system under
* pressure
*/
do {
if (next_mz)
mz = next_mz;
else
mz = mem_cgroup_largest_soft_limit_node(mctz);
if (!mz)
break;
nr_scanned = 0;
reclaimed = mem_cgroup_soft_reclaim(mz->memcg, zone,
gfp_mask, &nr_scanned);
nr_reclaimed += reclaimed;
*total_scanned += nr_scanned;
spin_lock_irq(&mctz->lock);
__mem_cgroup_remove_exceeded(mz, mctz);
/*
* If we failed to reclaim anything from this memory cgroup
* it is time to move on to the next cgroup
*/
next_mz = NULL;
if (!reclaimed)
next_mz = __mem_cgroup_largest_soft_limit_node(mctz);
excess = soft_limit_excess(mz->memcg);
/*
* One school of thought says that we should not add
* back the node to the tree if reclaim returns 0.
* But our reclaim could return 0, simply because due
* to priority we are exposing a smaller subset of
* memory to reclaim from. Consider this as a longer
* term TODO.
*/
/* If excess == 0, no tree ops */
__mem_cgroup_insert_exceeded(mz, mctz, excess);
spin_unlock_irq(&mctz->lock);
css_put(&mz->memcg->css);
loop++;
/*
* Could not reclaim anything and there are no more
* mem cgroups to try or we seem to be looping without
* reclaiming anything.
*/
if (!nr_reclaimed &&
(next_mz == NULL ||
loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
break;
} while (!nr_reclaimed);
if (next_mz)
css_put(&next_mz->memcg->css);
return nr_reclaimed;
}
/*
* Test whether @memcg has children, dead or alive. Note that this
* function doesn't care whether @memcg has use_hierarchy enabled and
* returns %true if there are child csses according to the cgroup
* hierarchy. Testing use_hierarchy is the caller's responsiblity.
*/
static inline bool memcg_has_children(struct mem_cgroup *memcg)
{
bool ret;
/*
* The lock does not prevent addition or deletion of children, but
* it prevents a new child from being initialized based on this
* parent in css_online(), so it's enough to decide whether
* hierarchically inherited attributes can still be changed or not.
*/
lockdep_assert_held(&memcg_create_mutex);
rcu_read_lock();
ret = css_next_child(NULL, &memcg->css);
rcu_read_unlock();
return ret;
}
/*
* Reclaims as many pages from the given memcg as possible and moves
* the rest to the parent.
*
* Caller is responsible for holding css reference for memcg.
*/
static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
{
int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
/* we call try-to-free pages for make this cgroup empty */
lru_add_drain_all();
/* try to free all pages in this cgroup */
while (nr_retries && page_counter_read(&memcg->memory)) {
int progress;
if (signal_pending(current))
return -EINTR;
progress = try_to_free_mem_cgroup_pages(memcg, 1,
GFP_KERNEL, true);
if (!progress) {
nr_retries--;
/* maybe some writeback is necessary */
congestion_wait(BLK_RW_ASYNC, HZ/10);
}
}
return 0;
}
static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of,
char *buf, size_t nbytes,
loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
if (mem_cgroup_is_root(memcg))
return -EINVAL;
return mem_cgroup_force_empty(memcg) ?: nbytes;
}
static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
return mem_cgroup_from_css(css)->use_hierarchy;
}
static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
struct cftype *cft, u64 val)
{
int retval = 0;
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
struct mem_cgroup *parent_memcg = mem_cgroup_from_css(memcg->css.parent);
mutex_lock(&memcg_create_mutex);
if (memcg->use_hierarchy == val)
goto out;
/*
* If parent's use_hierarchy is set, we can't make any modifications
* in the child subtrees. If it is unset, then the change can
* occur, provided the current cgroup has no children.
*
* For the root cgroup, parent_mem is NULL, we allow value to be
* set if there are no children.
*/
if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
(val == 1 || val == 0)) {
if (!memcg_has_children(memcg))
memcg->use_hierarchy = val;
else
retval = -EBUSY;
} else
retval = -EINVAL;
out:
mutex_unlock(&memcg_create_mutex);
return retval;
}
static unsigned long tree_stat(struct mem_cgroup *memcg,
enum mem_cgroup_stat_index idx)
{
struct mem_cgroup *iter;
long val = 0;
/* Per-cpu values can be negative, use a signed accumulator */
for_each_mem_cgroup_tree(iter, memcg)
val += mem_cgroup_read_stat(iter, idx);
if (val < 0) /* race ? */
val = 0;
return val;
}
static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
{
u64 val;
if (mem_cgroup_is_root(memcg)) {
val = tree_stat(memcg, MEM_CGROUP_STAT_CACHE);
val += tree_stat(memcg, MEM_CGROUP_STAT_RSS);
if (swap)
val += tree_stat(memcg, MEM_CGROUP_STAT_SWAP);
} else {
if (!swap)
val = page_counter_read(&memcg->memory);
else
val = page_counter_read(&memcg->memsw);
}
return val << PAGE_SHIFT;
}
enum {
RES_USAGE,
RES_LIMIT,
RES_MAX_USAGE,
RES_FAILCNT,
RES_SOFT_LIMIT,
};
static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
struct cftype *cft)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
struct page_counter *counter;
switch (MEMFILE_TYPE(cft->private)) {
case _MEM:
counter = &memcg->memory;
break;
case _MEMSWAP:
counter = &memcg->memsw;
break;
case _KMEM:
counter = &memcg->kmem;
break;
default:
BUG();
}
switch (MEMFILE_ATTR(cft->private)) {
case RES_USAGE:
if (counter == &memcg->memory)
return mem_cgroup_usage(memcg, false);
if (counter == &memcg->memsw)
return mem_cgroup_usage(memcg, true);
return (u64)page_counter_read(counter) * PAGE_SIZE;
case RES_LIMIT:
return (u64)counter->limit * PAGE_SIZE;
case RES_MAX_USAGE:
return (u64)counter->watermark * PAGE_SIZE;
case RES_FAILCNT:
return counter->failcnt;
case RES_SOFT_LIMIT:
return (u64)memcg->soft_limit * PAGE_SIZE;
default:
BUG();
}
}
#ifdef CONFIG_MEMCG_KMEM
static int memcg_activate_kmem(struct mem_cgroup *memcg,
unsigned long nr_pages)
{
int err = 0;
int memcg_id;
if (memcg_kmem_is_active(memcg))
return 0;
/*
* For simplicity, we won't allow this to be disabled. It also can't
* be changed if the cgroup has children already, or if tasks had
* already joined.
*
* If tasks join before we set the limit, a person looking at
* kmem.usage_in_bytes will have no way to determine when it took
* place, which makes the value quite meaningless.
*
* After it first became limited, changes in the value of the limit are
* of course permitted.
*/
mutex_lock(&memcg_create_mutex);
if (cgroup_has_tasks(memcg->css.cgroup) ||
(memcg->use_hierarchy && memcg_has_children(memcg)))
err = -EBUSY;
mutex_unlock(&memcg_create_mutex);
if (err)
goto out;
memcg_id = memcg_alloc_cache_id();
if (memcg_id < 0) {
err = memcg_id;
goto out;
}
/*
* We couldn't have accounted to this cgroup, because it hasn't got
* activated yet, so this should succeed.
*/
err = page_counter_limit(&memcg->kmem, nr_pages);
VM_BUG_ON(err);
static_key_slow_inc(&memcg_kmem_enabled_key);
/*
* A memory cgroup is considered kmem-active as soon as it gets
* kmemcg_id. Setting the id after enabling static branching will
* guarantee no one starts accounting before all call sites are
* patched.
*/
memcg->kmemcg_id = memcg_id;
out:
return err;
}
static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
unsigned long limit)
{
int ret;
mutex_lock(&memcg_limit_mutex);
if (!memcg_kmem_is_active(memcg))
ret = memcg_activate_kmem(memcg, limit);
else
ret = page_counter_limit(&memcg->kmem, limit);
mutex_unlock(&memcg_limit_mutex);
return ret;
}
static int memcg_propagate_kmem(struct mem_cgroup *memcg)
{
int ret = 0;
struct mem_cgroup *parent = parent_mem_cgroup(memcg);
if (!parent)
return 0;
mutex_lock(&memcg_limit_mutex);
/*
* If the parent cgroup is not kmem-active now, it cannot be activated
* after this point, because it has at least one child already.
*/
if (memcg_kmem_is_active(parent))
ret = memcg_activate_kmem(memcg, PAGE_COUNTER_MAX);
mutex_unlock(&memcg_limit_mutex);
return ret;
}
#else
static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
unsigned long limit)
{
return -EINVAL;
}
#endif /* CONFIG_MEMCG_KMEM */
/*
* The user of this function is...
* RES_LIMIT.
*/
static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
unsigned long nr_pages;
int ret;
buf = strstrip(buf);
ret = page_counter_memparse(buf, &nr_pages);
if (ret)
return ret;
switch (MEMFILE_ATTR(of_cft(of)->private)) {
case RES_LIMIT:
if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
ret = -EINVAL;
break;
}
switch (MEMFILE_TYPE(of_cft(of)->private)) {
case _MEM:
ret = mem_cgroup_resize_limit(memcg, nr_pages);
break;
case _MEMSWAP:
ret = mem_cgroup_resize_memsw_limit(memcg, nr_pages);
break;
case _KMEM:
ret = memcg_update_kmem_limit(memcg, nr_pages);
break;
}
break;
case RES_SOFT_LIMIT:
memcg->soft_limit = nr_pages;
ret = 0;
break;
}
return ret ?: nbytes;
}
static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf,
size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
struct page_counter *counter;
switch (MEMFILE_TYPE(of_cft(of)->private)) {
case _MEM:
counter = &memcg->memory;
break;
case _MEMSWAP:
counter = &memcg->memsw;
break;
case _KMEM:
counter = &memcg->kmem;
break;
default:
BUG();
}
switch (MEMFILE_ATTR(of_cft(of)->private)) {
case RES_MAX_USAGE:
page_counter_reset_watermark(counter);
break;
case RES_FAILCNT:
counter->failcnt = 0;
break;
default:
BUG();
}
return nbytes;
}
static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
return mem_cgroup_from_css(css)->move_charge_at_immigrate;
}
#ifdef CONFIG_MMU
static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
struct cftype *cft, u64 val)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
if (val >= (1 << NR_MOVE_TYPE))
return -EINVAL;
/*
* No kind of locking is needed in here, because ->can_attach() will
* check this value once in the beginning of the process, and then carry
* on with stale data. This means that changes to this value will only
* affect task migrations starting after the change.
*/
memcg->move_charge_at_immigrate = val;
return 0;
}
#else
static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
struct cftype *cft, u64 val)
{
return -ENOSYS;
}
#endif
#ifdef CONFIG_NUMA
static int memcg_numa_stat_show(struct seq_file *m, void *v)
{
struct numa_stat {
const char *name;
unsigned int lru_mask;
};
static const struct numa_stat stats[] = {
{ "total", LRU_ALL },
{ "file", LRU_ALL_FILE },
{ "anon", LRU_ALL_ANON },
{ "unevictable", BIT(LRU_UNEVICTABLE) },
};
const struct numa_stat *stat;
int nid;
unsigned long nr;
struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask);
seq_printf(m, "%s=%lu", stat->name, nr);
for_each_node_state(nid, N_MEMORY) {
nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
stat->lru_mask);
seq_printf(m, " N%d=%lu", nid, nr);
}
seq_putc(m, '\n');
}
for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
struct mem_cgroup *iter;
nr = 0;
for_each_mem_cgroup_tree(iter, memcg)
nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask);
seq_printf(m, "hierarchical_%s=%lu", stat->name, nr);
for_each_node_state(nid, N_MEMORY) {
nr = 0;
for_each_mem_cgroup_tree(iter, memcg)
nr += mem_cgroup_node_nr_lru_pages(
iter, nid, stat->lru_mask);
seq_printf(m, " N%d=%lu", nid, nr);
}
seq_putc(m, '\n');
}
return 0;
}
#endif /* CONFIG_NUMA */
static int memcg_stat_show(struct seq_file *m, void *v)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
unsigned long memory, memsw;
struct mem_cgroup *mi;
unsigned int i;
BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
continue;
seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i],
mem_cgroup_read_stat(memcg, i) * PAGE_SIZE);
}
for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++)
seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i],
mem_cgroup_read_events(memcg, i));
for (i = 0; i < NR_LRU_LISTS; i++)
seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE);
/* Hierarchical information */
memory = memsw = PAGE_COUNTER_MAX;
for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) {
memory = min(memory, mi->memory.limit);
memsw = min(memsw, mi->memsw.limit);
}
seq_printf(m, "hierarchical_memory_limit %llu\n",
(u64)memory * PAGE_SIZE);
if (do_swap_account)
seq_printf(m, "hierarchical_memsw_limit %llu\n",
(u64)memsw * PAGE_SIZE);
for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
long long val = 0;
if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
continue;
for_each_mem_cgroup_tree(mi, memcg)
val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE;
seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val);
}
for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
unsigned long long val = 0;
for_each_mem_cgroup_tree(mi, memcg)
val += mem_cgroup_read_events(mi, i);
seq_printf(m, "total_%s %llu\n",
mem_cgroup_events_names[i], val);
}
for (i = 0; i < NR_LRU_LISTS; i++) {
unsigned long long val = 0;
for_each_mem_cgroup_tree(mi, memcg)
val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE;
seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val);
}
#ifdef CONFIG_DEBUG_VM
{
int nid, zid;
struct mem_cgroup_per_zone *mz;
struct zone_reclaim_stat *rstat;
unsigned long recent_rotated[2] = {0, 0};
unsigned long recent_scanned[2] = {0, 0};
for_each_online_node(nid)
for (zid = 0; zid < MAX_NR_ZONES; zid++) {
mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
rstat = &mz->lruvec.reclaim_stat;
recent_rotated[0] += rstat->recent_rotated[0];
recent_rotated[1] += rstat->recent_rotated[1];
recent_scanned[0] += rstat->recent_scanned[0];
recent_scanned[1] += rstat->recent_scanned[1];
}
seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
}
#endif
return 0;
}
static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
return mem_cgroup_swappiness(memcg);
}
static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
struct cftype *cft, u64 val)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
if (val > 100)
return -EINVAL;
if (css->parent)
memcg->swappiness = val;
else
vm_swappiness = val;
return 0;
}
static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
{
struct mem_cgroup_threshold_ary *t;
unsigned long usage;
int i;
rcu_read_lock();
if (!swap)
t = rcu_dereference(memcg->thresholds.primary);
else
t = rcu_dereference(memcg->memsw_thresholds.primary);
if (!t)
goto unlock;
usage = mem_cgroup_usage(memcg, swap);
/*
* current_threshold points to threshold just below or equal to usage.
* If it's not true, a threshold was crossed after last
* call of __mem_cgroup_threshold().
*/
i = t->current_threshold;
/*
* Iterate backward over array of thresholds starting from
* current_threshold and check if a threshold is crossed.
* If none of thresholds below usage is crossed, we read
* only one element of the array here.
*/
for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
eventfd_signal(t->entries[i].eventfd, 1);
/* i = current_threshold + 1 */
i++;
/*
* Iterate forward over array of thresholds starting from
* current_threshold+1 and check if a threshold is crossed.
* If none of thresholds above usage is crossed, we read
* only one element of the array here.
*/
for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
eventfd_signal(t->entries[i].eventfd, 1);
/* Update current_threshold */
t->current_threshold = i - 1;
unlock:
rcu_read_unlock();
}
static void mem_cgroup_threshold(struct mem_cgroup *memcg)
{
while (memcg) {
__mem_cgroup_threshold(memcg, false);
if (do_swap_account)
__mem_cgroup_threshold(memcg, true);
memcg = parent_mem_cgroup(memcg);
}
}
static int compare_thresholds(const void *a, const void *b)
{
const struct mem_cgroup_threshold *_a = a;
const struct mem_cgroup_threshold *_b = b;
if (_a->threshold > _b->threshold)
return 1;
if (_a->threshold < _b->threshold)
return -1;
return 0;
}
static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
{
struct mem_cgroup_eventfd_list *ev;
spin_lock(&memcg_oom_lock);
list_for_each_entry(ev, &memcg->oom_notify, list)
eventfd_signal(ev->eventfd, 1);
spin_unlock(&memcg_oom_lock);
return 0;
}
static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
{
struct mem_cgroup *iter;
for_each_mem_cgroup_tree(iter, memcg)
mem_cgroup_oom_notify_cb(iter);
}
static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd, const char *args, enum res_type type)
{
struct mem_cgroup_thresholds *thresholds;
struct mem_cgroup_threshold_ary *new;
unsigned long threshold;
unsigned long usage;
int i, size, ret;
ret = page_counter_memparse(args, &threshold);
if (ret)
return ret;
mutex_lock(&memcg->thresholds_lock);
if (type == _MEM) {
thresholds = &memcg->thresholds;
usage = mem_cgroup_usage(memcg, false);
} else if (type == _MEMSWAP) {
thresholds = &memcg->memsw_thresholds;
usage = mem_cgroup_usage(memcg, true);
} else
BUG();
/* Check if a threshold crossed before adding a new one */
if (thresholds->primary)
__mem_cgroup_threshold(memcg, type == _MEMSWAP);
size = thresholds->primary ? thresholds->primary->size + 1 : 1;
/* Allocate memory for new array of thresholds */
new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
GFP_KERNEL);
if (!new) {
ret = -ENOMEM;
goto unlock;
}
new->size = size;
/* Copy thresholds (if any) to new array */
if (thresholds->primary) {
memcpy(new->entries, thresholds->primary->entries, (size - 1) *
sizeof(struct mem_cgroup_threshold));
}
/* Add new threshold */
new->entries[size - 1].eventfd = eventfd;
new->entries[size - 1].threshold = threshold;
/* Sort thresholds. Registering of new threshold isn't time-critical */
sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
compare_thresholds, NULL);
/* Find current threshold */
new->current_threshold = -1;
for (i = 0; i < size; i++) {
if (new->entries[i].threshold <= usage) {
/*
* new->current_threshold will not be used until
* rcu_assign_pointer(), so it's safe to increment
* it here.
*/
++new->current_threshold;
} else
break;
}
/* Free old spare buffer and save old primary buffer as spare */
kfree(thresholds->spare);
thresholds->spare = thresholds->primary;
rcu_assign_pointer(thresholds->primary, new);
/* To be sure that nobody uses thresholds */
synchronize_rcu();
unlock:
mutex_unlock(&memcg->thresholds_lock);
return ret;
}
static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd, const char *args)
{
return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM);
}
static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd, const char *args)
{
return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP);
}
static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd, enum res_type type)
{
struct mem_cgroup_thresholds *thresholds;
struct mem_cgroup_threshold_ary *new;
unsigned long usage;
int i, j, size;
mutex_lock(&memcg->thresholds_lock);
if (type == _MEM) {
thresholds = &memcg->thresholds;
usage = mem_cgroup_usage(memcg, false);
} else if (type == _MEMSWAP) {
thresholds = &memcg->memsw_thresholds;
usage = mem_cgroup_usage(memcg, true);
} else
BUG();
if (!thresholds->primary)
goto unlock;
/* Check if a threshold crossed before removing */
__mem_cgroup_threshold(memcg, type == _MEMSWAP);
/* Calculate new number of threshold */
size = 0;
for (i = 0; i < thresholds->primary->size; i++) {
if (thresholds->primary->entries[i].eventfd != eventfd)
size++;
}
new = thresholds->spare;
/* Set thresholds array to NULL if we don't have thresholds */
if (!size) {
kfree(new);
new = NULL;
goto swap_buffers;
}
new->size = size;
/* Copy thresholds and find current threshold */
new->current_threshold = -1;
for (i = 0, j = 0; i < thresholds->primary->size; i++) {
if (thresholds->primary->entries[i].eventfd == eventfd)
continue;
new->entries[j] = thresholds->primary->entries[i];
if (new->entries[j].threshold <= usage) {
/*
* new->current_threshold will not be used
* until rcu_assign_pointer(), so it's safe to increment
* it here.
*/
++new->current_threshold;
}
j++;
}
swap_buffers:
/* Swap primary and spare array */
thresholds->spare = thresholds->primary;
/* If all events are unregistered, free the spare array */
if (!new) {
kfree(thresholds->spare);
thresholds->spare = NULL;
}
rcu_assign_pointer(thresholds->primary, new);
/* To be sure that nobody uses thresholds */
synchronize_rcu();
unlock:
mutex_unlock(&memcg->thresholds_lock);
}
static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd)
{
return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM);
}
static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd)
{
return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP);
}
static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd, const char *args)
{
struct mem_cgroup_eventfd_list *event;
event = kmalloc(sizeof(*event), GFP_KERNEL);
if (!event)
return -ENOMEM;
spin_lock(&memcg_oom_lock);
event->eventfd = eventfd;
list_add(&event->list, &memcg->oom_notify);
/* already in OOM ? */
if (atomic_read(&memcg->under_oom))
eventfd_signal(eventfd, 1);
spin_unlock(&memcg_oom_lock);
return 0;
}
static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd)
{
struct mem_cgroup_eventfd_list *ev, *tmp;
spin_lock(&memcg_oom_lock);
list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
if (ev->eventfd == eventfd) {
list_del(&ev->list);
kfree(ev);
}
}
spin_unlock(&memcg_oom_lock);
}
static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(sf));
seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable);
seq_printf(sf, "under_oom %d\n", (bool)atomic_read(&memcg->under_oom));
return 0;
}
static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css,
struct cftype *cft, u64 val)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
/* cannot set to root cgroup and only 0 and 1 are allowed */
if (!css->parent || !((val == 0) || (val == 1)))
return -EINVAL;
memcg->oom_kill_disable = val;
if (!val)
memcg_oom_recover(memcg);
return 0;
}
#ifdef CONFIG_MEMCG_KMEM
static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
{
int ret;
ret = memcg_propagate_kmem(memcg);
if (ret)
return ret;
return mem_cgroup_sockets_init(memcg, ss);
}
static void memcg_destroy_kmem(struct mem_cgroup *memcg)
{
memcg_unregister_all_caches(memcg);
mem_cgroup_sockets_destroy(memcg);
}
#else
static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
{
return 0;
}
static void memcg_destroy_kmem(struct mem_cgroup *memcg)
{
}
#endif
/*
* DO NOT USE IN NEW FILES.
*
* "cgroup.event_control" implementation.
*
* This is way over-engineered. It tries to support fully configurable
* events for each user. Such level of flexibility is completely
* unnecessary especially in the light of the planned unified hierarchy.
*
* Please deprecate this and replace with something simpler if at all
* possible.
*/
/*
* Unregister event and free resources.
*
* Gets called from workqueue.
*/
static void memcg_event_remove(struct work_struct *work)
{
struct mem_cgroup_event *event =
container_of(work, struct mem_cgroup_event, remove);
struct mem_cgroup *memcg = event->memcg;
remove_wait_queue(event->wqh, &event->wait);
event->unregister_event(memcg, event->eventfd);
/* Notify userspace the event is going away. */
eventfd_signal(event->eventfd, 1);
eventfd_ctx_put(event->eventfd);
kfree(event);
css_put(&memcg->css);
}
/*
* Gets called on POLLHUP on eventfd when user closes it.
*
* Called with wqh->lock held and interrupts disabled.
*/
static int memcg_event_wake(wait_queue_t *wait, unsigned mode,
int sync, void *key)
{
struct mem_cgroup_event *event =
container_of(wait, struct mem_cgroup_event, wait);
struct mem_cgroup *memcg = event->memcg;
unsigned long flags = (unsigned long)key;
if (flags & POLLHUP) {
/*
* If the event has been detached at cgroup removal, we
* can simply return knowing the other side will cleanup
* for us.
*
* We can't race against event freeing since the other
* side will require wqh->lock via remove_wait_queue(),
* which we hold.
*/
spin_lock(&memcg->event_list_lock);
if (!list_empty(&event->list)) {
list_del_init(&event->list);
/*
* We are in atomic context, but cgroup_event_remove()
* may sleep, so we have to call it in workqueue.
*/
schedule_work(&event->remove);
}
spin_unlock(&memcg->event_list_lock);
}
return 0;
}
static void memcg_event_ptable_queue_proc(struct file *file,
wait_queue_head_t *wqh, poll_table *pt)
{
struct mem_cgroup_event *event =
container_of(pt, struct mem_cgroup_event, pt);
event->wqh = wqh;
add_wait_queue(wqh, &event->wait);
}
/*
* DO NOT USE IN NEW FILES.
*
* Parse input and register new cgroup event handler.
*
* Input must be in format '<event_fd> <control_fd> <args>'.
* Interpretation of args is defined by control file implementation.
*/
static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct cgroup_subsys_state *css = of_css(of);
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
struct mem_cgroup_event *event;
struct cgroup_subsys_state *cfile_css;
unsigned int efd, cfd;
struct fd efile;
struct fd cfile;
const char *name;
char *endp;
int ret;
buf = strstrip(buf);
efd = simple_strtoul(buf, &endp, 10);
if (*endp != ' ')
return -EINVAL;
buf = endp + 1;
cfd = simple_strtoul(buf, &endp, 10);
if ((*endp != ' ') && (*endp != '\0'))
return -EINVAL;
buf = endp + 1;
event = kzalloc(sizeof(*event), GFP_KERNEL);
if (!event)
return -ENOMEM;
event->memcg = memcg;
INIT_LIST_HEAD(&event->list);
init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc);
init_waitqueue_func_entry(&event->wait, memcg_event_wake);
INIT_WORK(&event->remove, memcg_event_remove);
efile = fdget(efd);
if (!efile.file) {
ret = -EBADF;
goto out_kfree;
}
event->eventfd = eventfd_ctx_fileget(efile.file);
if (IS_ERR(event->eventfd)) {
ret = PTR_ERR(event->eventfd);
goto out_put_efile;
}
cfile = fdget(cfd);
if (!cfile.file) {
ret = -EBADF;
goto out_put_eventfd;
}
/* the process need read permission on control file */
/* AV: shouldn't we check that it's been opened for read instead? */
ret = inode_permission(file_inode(cfile.file), MAY_READ);
if (ret < 0)
goto out_put_cfile;
/*
* Determine the event callbacks and set them in @event. This used
* to be done via struct cftype but cgroup core no longer knows
* about these events. The following is crude but the whole thing
* is for compatibility anyway.
*
* DO NOT ADD NEW FILES.
*/
name = cfile.file->f_path.dentry->d_name.name;
if (!strcmp(name, "memory.usage_in_bytes")) {
event->register_event = mem_cgroup_usage_register_event;
event->unregister_event = mem_cgroup_usage_unregister_event;
} else if (!strcmp(name, "memory.oom_control")) {
event->register_event = mem_cgroup_oom_register_event;
event->unregister_event = mem_cgroup_oom_unregister_event;
} else if (!strcmp(name, "memory.pressure_level")) {
event->register_event = vmpressure_register_event;
event->unregister_event = vmpressure_unregister_event;
} else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
event->register_event = memsw_cgroup_usage_register_event;
event->unregister_event = memsw_cgroup_usage_unregister_event;
} else {
ret = -EINVAL;
goto out_put_cfile;
}
/*
* Verify @cfile should belong to @css. Also, remaining events are
* automatically removed on cgroup destruction but the removal is
* asynchronous, so take an extra ref on @css.
*/
cfile_css = css_tryget_online_from_dir(cfile.file->f_path.dentry->d_parent,
&memory_cgrp_subsys);
ret = -EINVAL;
if (IS_ERR(cfile_css))
goto out_put_cfile;
if (cfile_css != css) {
css_put(cfile_css);
goto out_put_cfile;
}
ret = event->register_event(memcg, event->eventfd, buf);
if (ret)
goto out_put_css;
efile.file->f_op->poll(efile.file, &event->pt);
spin_lock(&memcg->event_list_lock);
list_add(&event->list, &memcg->event_list);
spin_unlock(&memcg->event_list_lock);
fdput(cfile);
fdput(efile);
return nbytes;
out_put_css:
css_put(css);
out_put_cfile:
fdput(cfile);
out_put_eventfd:
eventfd_ctx_put(event->eventfd);
out_put_efile:
fdput(efile);
out_kfree:
kfree(event);
return ret;
}
static struct cftype mem_cgroup_files[] = {
{
.name = "usage_in_bytes",
.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "max_usage_in_bytes",
.private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
.write = mem_cgroup_reset,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "limit_in_bytes",
.private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
.write = mem_cgroup_write,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "soft_limit_in_bytes",
.private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
.write = mem_cgroup_write,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "failcnt",
.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
.write = mem_cgroup_reset,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "stat",
.seq_show = memcg_stat_show,
},
{
.name = "force_empty",
.write = mem_cgroup_force_empty_write,
},
{
.name = "use_hierarchy",
.write_u64 = mem_cgroup_hierarchy_write,
.read_u64 = mem_cgroup_hierarchy_read,
},
{
.name = "cgroup.event_control", /* XXX: for compat */
.write = memcg_write_event_control,
.flags = CFTYPE_NO_PREFIX,
.mode = S_IWUGO,
},
{
.name = "swappiness",
.read_u64 = mem_cgroup_swappiness_read,
.write_u64 = mem_cgroup_swappiness_write,
},
{
.name = "move_charge_at_immigrate",
.read_u64 = mem_cgroup_move_charge_read,
.write_u64 = mem_cgroup_move_charge_write,
},
{
.name = "oom_control",
.seq_show = mem_cgroup_oom_control_read,
.write_u64 = mem_cgroup_oom_control_write,
.private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
},
{
.name = "pressure_level",
},
#ifdef CONFIG_NUMA
{
.name = "numa_stat",
.seq_show = memcg_numa_stat_show,
},
#endif
#ifdef CONFIG_MEMCG_KMEM
{
.name = "kmem.limit_in_bytes",
.private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
.write = mem_cgroup_write,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "kmem.usage_in_bytes",
.private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "kmem.failcnt",
.private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
.write = mem_cgroup_reset,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "kmem.max_usage_in_bytes",
.private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
.write = mem_cgroup_reset,
.read_u64 = mem_cgroup_read_u64,
},
#ifdef CONFIG_SLABINFO
{
.name = "kmem.slabinfo",
.seq_start = slab_start,
.seq_next = slab_next,
.seq_stop = slab_stop,
.seq_show = memcg_slab_show,
},
#endif
#endif
{ }, /* terminate */
};
#ifdef CONFIG_MEMCG_SWAP
static struct cftype memsw_cgroup_files[] = {
{
.name = "memsw.usage_in_bytes",
.private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "memsw.max_usage_in_bytes",
.private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
.write = mem_cgroup_reset,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "memsw.limit_in_bytes",
.private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
.write = mem_cgroup_write,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "memsw.failcnt",
.private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
.write = mem_cgroup_reset,
.read_u64 = mem_cgroup_read_u64,
},
{ }, /* terminate */
};
#endif
static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
{
struct mem_cgroup_per_node *pn;
struct mem_cgroup_per_zone *mz;
int zone, tmp = node;
/*
* This routine is called against possible nodes.
* But it's BUG to call kmalloc() against offline node.
*
* TODO: this routine can waste much memory for nodes which will
* never be onlined. It's better to use memory hotplug callback
* function.
*/
if (!node_state(node, N_NORMAL_MEMORY))
tmp = -1;
pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
if (!pn)
return 1;
for (zone = 0; zone < MAX_NR_ZONES; zone++) {
mz = &pn->zoneinfo[zone];
lruvec_init(&mz->lruvec);
mz->usage_in_excess = 0;
mz->on_tree = false;
mz->memcg = memcg;
}
memcg->nodeinfo[node] = pn;
return 0;
}
static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
{
kfree(memcg->nodeinfo[node]);
}
static struct mem_cgroup *mem_cgroup_alloc(void)
{
struct mem_cgroup *memcg;
size_t size;
size = sizeof(struct mem_cgroup);
size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
memcg = kzalloc(size, GFP_KERNEL);
if (!memcg)
return NULL;
memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
if (!memcg->stat)
goto out_free;
spin_lock_init(&memcg->pcp_counter_lock);
return memcg;
out_free:
kfree(memcg);
return NULL;
}
/*
* At destroying mem_cgroup, references from swap_cgroup can remain.
* (scanning all at force_empty is too costly...)
*
* Instead of clearing all references at force_empty, we remember
* the number of reference from swap_cgroup and free mem_cgroup when
* it goes down to 0.
*
* Removal of cgroup itself succeeds regardless of refs from swap.
*/
static void __mem_cgroup_free(struct mem_cgroup *memcg)
{
int node;
mem_cgroup_remove_from_trees(memcg);
for_each_node(node)
free_mem_cgroup_per_zone_info(memcg, node);
free_percpu(memcg->stat);
disarm_static_keys(memcg);
kfree(memcg);
}
/*
* Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
*/
struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
{
if (!memcg->memory.parent)
return NULL;
return mem_cgroup_from_counter(memcg->memory.parent, memory);
}
EXPORT_SYMBOL(parent_mem_cgroup);
static void __init mem_cgroup_soft_limit_tree_init(void)
{
struct mem_cgroup_tree_per_node *rtpn;
struct mem_cgroup_tree_per_zone *rtpz;
int tmp, node, zone;
for_each_node(node) {
tmp = node;
if (!node_state(node, N_NORMAL_MEMORY))
tmp = -1;
rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
BUG_ON(!rtpn);
soft_limit_tree.rb_tree_per_node[node] = rtpn;
for (zone = 0; zone < MAX_NR_ZONES; zone++) {
rtpz = &rtpn->rb_tree_per_zone[zone];
rtpz->rb_root = RB_ROOT;
spin_lock_init(&rtpz->lock);
}
}
}
static struct cgroup_subsys_state * __ref
mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
{
struct mem_cgroup *memcg;
long error = -ENOMEM;
int node;
memcg = mem_cgroup_alloc();
if (!memcg)
return ERR_PTR(error);
for_each_node(node)
if (alloc_mem_cgroup_per_zone_info(memcg, node))
goto free_out;
/* root ? */
if (parent_css == NULL) {
root_mem_cgroup = memcg;
page_counter_init(&memcg->memory, NULL);
page_counter_init(&memcg->memsw, NULL);
page_counter_init(&memcg->kmem, NULL);
}
memcg->last_scanned_node = MAX_NUMNODES;
INIT_LIST_HEAD(&memcg->oom_notify);
memcg->move_charge_at_immigrate = 0;
mutex_init(&memcg->thresholds_lock);
spin_lock_init(&memcg->move_lock);
vmpressure_init(&memcg->vmpressure);
INIT_LIST_HEAD(&memcg->event_list);
spin_lock_init(&memcg->event_list_lock);
#ifdef CONFIG_MEMCG_KMEM
memcg->kmemcg_id = -1;
INIT_LIST_HEAD(&memcg->memcg_slab_caches);
#endif
return &memcg->css;
free_out:
__mem_cgroup_free(memcg);
return ERR_PTR(error);
}
static int
mem_cgroup_css_online(struct cgroup_subsys_state *css)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
struct mem_cgroup *parent = mem_cgroup_from_css(css->parent);
int ret;
if (css->id > MEM_CGROUP_ID_MAX)
return -ENOSPC;
if (!parent)
return 0;
mutex_lock(&memcg_create_mutex);
memcg->use_hierarchy = parent->use_hierarchy;
memcg->oom_kill_disable = parent->oom_kill_disable;
memcg->swappiness = mem_cgroup_swappiness(parent);
if (parent->use_hierarchy) {
page_counter_init(&memcg->memory, &parent->memory);
page_counter_init(&memcg->memsw, &parent->memsw);
page_counter_init(&memcg->kmem, &parent->kmem);
/*
* No need to take a reference to the parent because cgroup
* core guarantees its existence.
*/
} else {
page_counter_init(&memcg->memory, NULL);
page_counter_init(&memcg->memsw, NULL);
page_counter_init(&memcg->kmem, NULL);
/*
* Deeper hierachy with use_hierarchy == false doesn't make
* much sense so let cgroup subsystem know about this
* unfortunate state in our controller.
*/
if (parent != root_mem_cgroup)
memory_cgrp_subsys.broken_hierarchy = true;
}
mutex_unlock(&memcg_create_mutex);
ret = memcg_init_kmem(memcg, &memory_cgrp_subsys);
if (ret)
return ret;
/*
* Make sure the memcg is initialized: mem_cgroup_iter()
* orders reading memcg->initialized against its callers
* reading the memcg members.
*/
smp_store_release(&memcg->initialized, 1);
return 0;
}
static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
struct mem_cgroup_event *event, *tmp;
/*
* Unregister events and notify userspace.
* Notify userspace about cgroup removing only after rmdir of cgroup
* directory to avoid race between userspace and kernelspace.
*/
spin_lock(&memcg->event_list_lock);
list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
list_del_init(&event->list);
schedule_work(&event->remove);
}
spin_unlock(&memcg->event_list_lock);
vmpressure_cleanup(&memcg->vmpressure);
}
static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
memcg_destroy_kmem(memcg);
__mem_cgroup_free(memcg);
}
/**
* mem_cgroup_css_reset - reset the states of a mem_cgroup
* @css: the target css
*
* Reset the states of the mem_cgroup associated with @css. This is
* invoked when the userland requests disabling on the default hierarchy
* but the memcg is pinned through dependency. The memcg should stop
* applying policies and should revert to the vanilla state as it may be
* made visible again.
*
* The current implementation only resets the essential configurations.
* This needs to be expanded to cover all the visible parts.
*/
static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
mem_cgroup_resize_limit(memcg, PAGE_COUNTER_MAX);
mem_cgroup_resize_memsw_limit(memcg, PAGE_COUNTER_MAX);
memcg_update_kmem_limit(memcg, PAGE_COUNTER_MAX);
memcg->soft_limit = 0;
}
#ifdef CONFIG_MMU
/* Handlers for move charge at task migration. */
static int mem_cgroup_do_precharge(unsigned long count)
{
int ret;
/* Try a single bulk charge without reclaim first */
ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_WAIT, count);
if (!ret) {
mc.precharge += count;
return ret;
}
if (ret == -EINTR) {
cancel_charge(root_mem_cgroup, count);
return ret;
}
/* Try charges one by one with reclaim */
while (count--) {
ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_NORETRY, 1);
/*
* In case of failure, any residual charges against
* mc.to will be dropped by mem_cgroup_clear_mc()
* later on. However, cancel any charges that are
* bypassed to root right away or they'll be lost.
*/
if (ret == -EINTR)
cancel_charge(root_mem_cgroup, 1);
if (ret)
return ret;
mc.precharge++;
cond_resched();
}
return 0;
}
/**
* get_mctgt_type - get target type of moving charge
* @vma: the vma the pte to be checked belongs
* @addr: the address corresponding to the pte to be checked
* @ptent: the pte to be checked
* @target: the pointer the target page or swap ent will be stored(can be NULL)
*
* Returns
* 0(MC_TARGET_NONE): if the pte is not a target for move charge.
* 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
* move charge. if @target is not NULL, the page is stored in target->page
* with extra refcnt got(Callers should handle it).
* 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
* target for charge migration. if @target is not NULL, the entry is stored
* in target->ent.
*
* Called with pte lock held.
*/
union mc_target {
struct page *page;
swp_entry_t ent;
};
enum mc_target_type {
MC_TARGET_NONE = 0,
MC_TARGET_PAGE,
MC_TARGET_SWAP,
};
static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
unsigned long addr, pte_t ptent)
{
struct page *page = vm_normal_page(vma, addr, ptent);
if (!page || !page_mapped(page))
return NULL;
if (PageAnon(page)) {
/* we don't move shared anon */
if (!move_anon())
return NULL;
} else if (!move_file())
/* we ignore mapcount for file pages */
return NULL;
if (!get_page_unless_zero(page))
return NULL;
return page;
}
#ifdef CONFIG_SWAP
static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
unsigned long addr, pte_t ptent, swp_entry_t *entry)
{
struct page *page = NULL;
swp_entry_t ent = pte_to_swp_entry(ptent);
if (!move_anon() || non_swap_entry(ent))
return NULL;
/*
* Because lookup_swap_cache() updates some statistics counter,
* we call find_get_page() with swapper_space directly.
*/
page = find_get_page(swap_address_space(ent), ent.val);
if (do_swap_account)
entry->val = ent.val;
return page;
}
#else
static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
unsigned long addr, pte_t ptent, swp_entry_t *entry)
{
return NULL;
}
#endif
static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
unsigned long addr, pte_t ptent, swp_entry_t *entry)
{
struct page *page = NULL;
struct address_space *mapping;
pgoff_t pgoff;
if (!vma->vm_file) /* anonymous vma */
return NULL;
if (!move_file())
return NULL;
mapping = vma->vm_file->f_mapping;
if (pte_none(ptent))
pgoff = linear_page_index(vma, addr);
else /* pte_file(ptent) is true */
pgoff = pte_to_pgoff(ptent);
/* page is moved even if it's not RSS of this task(page-faulted). */
#ifdef CONFIG_SWAP
/* shmem/tmpfs may report page out on swap: account for that too. */
if (shmem_mapping(mapping)) {
page = find_get_entry(mapping, pgoff);
if (radix_tree_exceptional_entry(page)) {
swp_entry_t swp = radix_to_swp_entry(page);
if (do_swap_account)
*entry = swp;
page = find_get_page(swap_address_space(swp), swp.val);
}
} else
page = find_get_page(mapping, pgoff);
#else
page = find_get_page(mapping, pgoff);
#endif
return page;
}
static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
unsigned long addr, pte_t ptent, union mc_target *target)
{
struct page *page = NULL;
enum mc_target_type ret = MC_TARGET_NONE;
swp_entry_t ent = { .val = 0 };
if (pte_present(ptent))
page = mc_handle_present_pte(vma, addr, ptent);
else if (is_swap_pte(ptent))
page = mc_handle_swap_pte(vma, addr, ptent, &ent);
else if (pte_none(ptent) || pte_file(ptent))
page = mc_handle_file_pte(vma, addr, ptent, &ent);
if (!page && !ent.val)
return ret;
if (page) {
/*
* Do only loose check w/o serialization.
* mem_cgroup_move_account() checks the page is valid or
* not under LRU exclusion.
*/
if (page->mem_cgroup == mc.from) {
ret = MC_TARGET_PAGE;
if (target)
target->page = page;
}
if (!ret || !target)
put_page(page);
}
/* There is a swap entry and a page doesn't exist or isn't charged */
if (ent.val && !ret &&
mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) {
ret = MC_TARGET_SWAP;
if (target)
target->ent = ent;
}
return ret;
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/*
* We don't consider swapping or file mapped pages because THP does not
* support them for now.
* Caller should make sure that pmd_trans_huge(pmd) is true.
*/
static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
unsigned long addr, pmd_t pmd, union mc_target *target)
{
struct page *page = NULL;
enum mc_target_type ret = MC_TARGET_NONE;
page = pmd_page(pmd);
VM_BUG_ON_PAGE(!page || !PageHead(page), page);
if (!move_anon())
return ret;
if (page->mem_cgroup == mc.from) {
ret = MC_TARGET_PAGE;
if (target) {
get_page(page);
target->page = page;
}
}
return ret;
}
#else
static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
unsigned long addr, pmd_t pmd, union mc_target *target)
{
return MC_TARGET_NONE;
}
#endif
static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
unsigned long addr, unsigned long end,
struct mm_walk *walk)
{
struct vm_area_struct *vma = walk->private;
pte_t *pte;
spinlock_t *ptl;
if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
mc.precharge += HPAGE_PMD_NR;
spin_unlock(ptl);
return 0;
}
if (pmd_trans_unstable(pmd))
return 0;
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
for (; addr != end; pte++, addr += PAGE_SIZE)
if (get_mctgt_type(vma, addr, *pte, NULL))
mc.precharge++; /* increment precharge temporarily */
pte_unmap_unlock(pte - 1, ptl);
cond_resched();
return 0;
}
static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
{
unsigned long precharge;
struct vm_area_struct *vma;
down_read(&mm->mmap_sem);
for (vma = mm->mmap; vma; vma = vma->vm_next) {
struct mm_walk mem_cgroup_count_precharge_walk = {
.pmd_entry = mem_cgroup_count_precharge_pte_range,
.mm = mm,
.private = vma,
};
if (is_vm_hugetlb_page(vma))
continue;
walk_page_range(vma->vm_start, vma->vm_end,
&mem_cgroup_count_precharge_walk);
}
up_read(&mm->mmap_sem);
precharge = mc.precharge;
mc.precharge = 0;
return precharge;
}
static int mem_cgroup_precharge_mc(struct mm_struct *mm)
{
unsigned long precharge = mem_cgroup_count_precharge(mm);
VM_BUG_ON(mc.moving_task);
mc.moving_task = current;
return mem_cgroup_do_precharge(precharge);
}
/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
static void __mem_cgroup_clear_mc(void)
{
struct mem_cgroup *from = mc.from;
struct mem_cgroup *to = mc.to;
/* we must uncharge all the leftover precharges from mc.to */
if (mc.precharge) {
cancel_charge(mc.to, mc.precharge);
mc.precharge = 0;
}
/*
* we didn't uncharge from mc.from at mem_cgroup_move_account(), so
* we must uncharge here.
*/
if (mc.moved_charge) {
cancel_charge(mc.from, mc.moved_charge);
mc.moved_charge = 0;
}
/* we must fixup refcnts and charges */
if (mc.moved_swap) {
/* uncharge swap account from the old cgroup */
if (!mem_cgroup_is_root(mc.from))
page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
/*
* we charged both to->memory and to->memsw, so we
* should uncharge to->memory.
*/
if (!mem_cgroup_is_root(mc.to))
page_counter_uncharge(&mc.to->memory, mc.moved_swap);
css_put_many(&mc.from->css, mc.moved_swap);
/* we've already done css_get(mc.to) */
mc.moved_swap = 0;
}
memcg_oom_recover(from);
memcg_oom_recover(to);
wake_up_all(&mc.waitq);
}
static void mem_cgroup_clear_mc(void)
{
/*
* we must clear moving_task before waking up waiters at the end of
* task migration.
*/
mc.moving_task = NULL;
__mem_cgroup_clear_mc();
spin_lock(&mc.lock);
mc.from = NULL;
mc.to = NULL;
spin_unlock(&mc.lock);
}
static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
struct cgroup_taskset *tset)
{
struct task_struct *p = cgroup_taskset_first(tset);
int ret = 0;
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
unsigned long move_charge_at_immigrate;
/*
* We are now commited to this value whatever it is. Changes in this
* tunable will only affect upcoming migrations, not the current one.
* So we need to save it, and keep it going.
*/
move_charge_at_immigrate = memcg->move_charge_at_immigrate;
if (move_charge_at_immigrate) {
struct mm_struct *mm;
struct mem_cgroup *from = mem_cgroup_from_task(p);
VM_BUG_ON(from == memcg);
mm = get_task_mm(p);
if (!mm)
return 0;
/* We move charges only when we move a owner of the mm */
if (mm->owner == p) {
VM_BUG_ON(mc.from);
VM_BUG_ON(mc.to);
VM_BUG_ON(mc.precharge);
VM_BUG_ON(mc.moved_charge);
VM_BUG_ON(mc.moved_swap);
spin_lock(&mc.lock);
mc.from = from;
mc.to = memcg;
mc.immigrate_flags = move_charge_at_immigrate;
spin_unlock(&mc.lock);
/* We set mc.moving_task later */
ret = mem_cgroup_precharge_mc(mm);
if (ret)
mem_cgroup_clear_mc();
}
mmput(mm);
}
return ret;
}
static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
struct cgroup_taskset *tset)
{
if (mc.to)
mem_cgroup_clear_mc();
}
static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
unsigned long addr, unsigned long end,
struct mm_walk *walk)
{
int ret = 0;
struct vm_area_struct *vma = walk->private;
pte_t *pte;
spinlock_t *ptl;
enum mc_target_type target_type;
union mc_target target;
struct page *page;
/*
* We don't take compound_lock() here but no race with splitting thp
* happens because:
* - if pmd_trans_huge_lock() returns 1, the relevant thp is not
* under splitting, which means there's no concurrent thp split,
* - if another thread runs into split_huge_page() just after we
* entered this if-block, the thread must wait for page table lock
* to be unlocked in __split_huge_page_splitting(), where the main
* part of thp split is not executed yet.
*/
if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
if (mc.precharge < HPAGE_PMD_NR) {
spin_unlock(ptl);
return 0;
}
target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
if (target_type == MC_TARGET_PAGE) {
page = target.page;
if (!isolate_lru_page(page)) {
if (!mem_cgroup_move_account(page, HPAGE_PMD_NR,
mc.from, mc.to)) {
mc.precharge -= HPAGE_PMD_NR;
mc.moved_charge += HPAGE_PMD_NR;
}
putback_lru_page(page);
}
put_page(page);
}
spin_unlock(ptl);
return 0;
}
if (pmd_trans_unstable(pmd))
return 0;
retry:
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
for (; addr != end; addr += PAGE_SIZE) {
pte_t ptent = *(pte++);
swp_entry_t ent;
if (!mc.precharge)
break;
switch (get_mctgt_type(vma, addr, ptent, &target)) {
case MC_TARGET_PAGE:
page = target.page;
if (isolate_lru_page(page))
goto put;
if (!mem_cgroup_move_account(page, 1, mc.from, mc.to)) {
mc.precharge--;
/* we uncharge from mc.from later. */
mc.moved_charge++;
}
putback_lru_page(page);
put: /* get_mctgt_type() gets the page */
put_page(page);
break;
case MC_TARGET_SWAP:
ent = target.ent;
if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
mc.precharge--;
/* we fixup refcnts and charges later. */
mc.moved_swap++;
}
break;
default:
break;
}
}
pte_unmap_unlock(pte - 1, ptl);
cond_resched();
if (addr != end) {
/*
* We have consumed all precharges we got in can_attach().
* We try charge one by one, but don't do any additional
* charges to mc.to if we have failed in charge once in attach()
* phase.
*/
ret = mem_cgroup_do_precharge(1);
if (!ret)
goto retry;
}
return ret;
}
static void mem_cgroup_move_charge(struct mm_struct *mm)
{
struct vm_area_struct *vma;
lru_add_drain_all();
/*
* Signal mem_cgroup_begin_page_stat() to take the memcg's
* move_lock while we're moving its pages to another memcg.
* Then wait for already started RCU-only updates to finish.
*/
atomic_inc(&mc.from->moving_account);
synchronize_rcu();
retry:
if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
/*
* Someone who are holding the mmap_sem might be waiting in
* waitq. So we cancel all extra charges, wake up all waiters,
* and retry. Because we cancel precharges, we might not be able
* to move enough charges, but moving charge is a best-effort
* feature anyway, so it wouldn't be a big problem.
*/
__mem_cgroup_clear_mc();
cond_resched();
goto retry;
}
for (vma = mm->mmap; vma; vma = vma->vm_next) {
int ret;
struct mm_walk mem_cgroup_move_charge_walk = {
.pmd_entry = mem_cgroup_move_charge_pte_range,
.mm = mm,
.private = vma,
};
if (is_vm_hugetlb_page(vma))
continue;
ret = walk_page_range(vma->vm_start, vma->vm_end,
&mem_cgroup_move_charge_walk);
if (ret)
/*
* means we have consumed all precharges and failed in
* doing additional charge. Just abandon here.
*/
break;
}
up_read(&mm->mmap_sem);
atomic_dec(&mc.from->moving_account);
}
static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
struct cgroup_taskset *tset)
{
struct task_struct *p = cgroup_taskset_first(tset);
struct mm_struct *mm = get_task_mm(p);
if (mm) {
if (mc.to)
mem_cgroup_move_charge(mm);
mmput(mm);
}
if (mc.to)
mem_cgroup_clear_mc();
}
#else /* !CONFIG_MMU */
static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
struct cgroup_taskset *tset)
{
return 0;
}
static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
struct cgroup_taskset *tset)
{
}
static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
struct cgroup_taskset *tset)
{
}
#endif
/*
* Cgroup retains root cgroups across [un]mount cycles making it necessary
* to verify whether we're attached to the default hierarchy on each mount
* attempt.
*/
static void mem_cgroup_bind(struct cgroup_subsys_state *root_css)
{
/*
* use_hierarchy is forced on the default hierarchy. cgroup core
* guarantees that @root doesn't have any children, so turning it
* on for the root memcg is enough.
*/
if (cgroup_on_dfl(root_css->cgroup))
mem_cgroup_from_css(root_css)->use_hierarchy = true;
}
struct cgroup_subsys memory_cgrp_subsys = {
.css_alloc = mem_cgroup_css_alloc,
.css_online = mem_cgroup_css_online,
.css_offline = mem_cgroup_css_offline,
.css_free = mem_cgroup_css_free,
.css_reset = mem_cgroup_css_reset,
.can_attach = mem_cgroup_can_attach,
.cancel_attach = mem_cgroup_cancel_attach,
.attach = mem_cgroup_move_task,
.bind = mem_cgroup_bind,
.legacy_cftypes = mem_cgroup_files,
.early_init = 0,
};
#ifdef CONFIG_MEMCG_SWAP
static int __init enable_swap_account(char *s)
{
if (!strcmp(s, "1"))
really_do_swap_account = 1;
else if (!strcmp(s, "0"))
really_do_swap_account = 0;
return 1;
}
__setup("swapaccount=", enable_swap_account);
static void __init memsw_file_init(void)
{
WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys,
memsw_cgroup_files));
}
static void __init enable_swap_cgroup(void)
{
if (!mem_cgroup_disabled() && really_do_swap_account) {
do_swap_account = 1;
memsw_file_init();
}
}
#else
static void __init enable_swap_cgroup(void)
{
}
#endif
#ifdef CONFIG_MEMCG_SWAP
/**
* mem_cgroup_swapout - transfer a memsw charge to swap
* @page: page whose memsw charge to transfer
* @entry: swap entry to move the charge to
*
* Transfer the memsw charge of @page to @entry.
*/
void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
{
struct mem_cgroup *memcg;
unsigned short oldid;
VM_BUG_ON_PAGE(PageLRU(page), page);
VM_BUG_ON_PAGE(page_count(page), page);
if (!do_swap_account)
return;
memcg = page->mem_cgroup;
/* Readahead page, never charged */
if (!memcg)
return;
oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg));
VM_BUG_ON_PAGE(oldid, page);
mem_cgroup_swap_statistics(memcg, true);
page->mem_cgroup = NULL;
if (!mem_cgroup_is_root(memcg))
page_counter_uncharge(&memcg->memory, 1);
/* XXX: caller holds IRQ-safe mapping->tree_lock */
VM_BUG_ON(!irqs_disabled());
mem_cgroup_charge_statistics(memcg, page, -1);
memcg_check_events(memcg, page);
}
/**
* mem_cgroup_uncharge_swap - uncharge a swap entry
* @entry: swap entry to uncharge
*
* Drop the memsw charge associated with @entry.
*/
void mem_cgroup_uncharge_swap(swp_entry_t entry)
{
struct mem_cgroup *memcg;
unsigned short id;
if (!do_swap_account)
return;
id = swap_cgroup_record(entry, 0);
rcu_read_lock();
memcg = mem_cgroup_lookup(id);
if (memcg) {
if (!mem_cgroup_is_root(memcg))
page_counter_uncharge(&memcg->memsw, 1);
mem_cgroup_swap_statistics(memcg, false);
css_put(&memcg->css);
}
rcu_read_unlock();
}
#endif
/**
* mem_cgroup_try_charge - try charging a page
* @page: page to charge
* @mm: mm context of the victim
* @gfp_mask: reclaim mode
* @memcgp: charged memcg return
*
* Try to charge @page to the memcg that @mm belongs to, reclaiming
* pages according to @gfp_mask if necessary.
*
* Returns 0 on success, with *@memcgp pointing to the charged memcg.
* Otherwise, an error code is returned.
*
* After page->mapping has been set up, the caller must finalize the
* charge with mem_cgroup_commit_charge(). Or abort the transaction
* with mem_cgroup_cancel_charge() in case page instantiation fails.
*/
int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask, struct mem_cgroup **memcgp)
{
struct mem_cgroup *memcg = NULL;
unsigned int nr_pages = 1;
int ret = 0;
if (mem_cgroup_disabled())
goto out;
if (PageSwapCache(page)) {
/*
* Every swap fault against a single page tries to charge the
* page, bail as early as possible. shmem_unuse() encounters
* already charged pages, too. The USED bit is protected by
* the page lock, which serializes swap cache removal, which
* in turn serializes uncharging.
*/
if (page->mem_cgroup)
goto out;
}
if (PageTransHuge(page)) {
nr_pages <<= compound_order(page);
VM_BUG_ON_PAGE(!PageTransHuge(page), page);
}
if (do_swap_account && PageSwapCache(page))
memcg = try_get_mem_cgroup_from_page(page);
if (!memcg)
memcg = get_mem_cgroup_from_mm(mm);
ret = try_charge(memcg, gfp_mask, nr_pages);
css_put(&memcg->css);
if (ret == -EINTR) {
memcg = root_mem_cgroup;
ret = 0;
}
out:
*memcgp = memcg;
return ret;
}
/**
* mem_cgroup_commit_charge - commit a page charge
* @page: page to charge
* @memcg: memcg to charge the page to
* @lrucare: page might be on LRU already
*
* Finalize a charge transaction started by mem_cgroup_try_charge(),
* after page->mapping has been set up. This must happen atomically
* as part of the page instantiation, i.e. under the page table lock
* for anonymous pages, under the page lock for page and swap cache.
*
* In addition, the page must not be on the LRU during the commit, to
* prevent racing with task migration. If it might be, use @lrucare.
*
* Use mem_cgroup_cancel_charge() to cancel the transaction instead.
*/
void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,
bool lrucare)
{
unsigned int nr_pages = 1;
VM_BUG_ON_PAGE(!page->mapping, page);
VM_BUG_ON_PAGE(PageLRU(page) && !lrucare, page);
if (mem_cgroup_disabled())
return;
/*
* Swap faults will attempt to charge the same page multiple
* times. But reuse_swap_page() might have removed the page
* from swapcache already, so we can't check PageSwapCache().
*/
if (!memcg)
return;
commit_charge(page, memcg, lrucare);
if (PageTransHuge(page)) {
nr_pages <<= compound_order(page);
VM_BUG_ON_PAGE(!PageTransHuge(page), page);
}
local_irq_disable();
mem_cgroup_charge_statistics(memcg, page, nr_pages);
memcg_check_events(memcg, page);
local_irq_enable();
if (do_swap_account && PageSwapCache(page)) {
swp_entry_t entry = { .val = page_private(page) };
/*
* The swap entry might not get freed for a long time,
* let's not wait for it. The page already received a
* memory+swap charge, drop the swap entry duplicate.
*/
mem_cgroup_uncharge_swap(entry);
}
}
/**
* mem_cgroup_cancel_charge - cancel a page charge
* @page: page to charge
* @memcg: memcg to charge the page to
*
* Cancel a charge transaction started by mem_cgroup_try_charge().
*/
void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg)
{
unsigned int nr_pages = 1;
if (mem_cgroup_disabled())
return;
/*
* Swap faults will attempt to charge the same page multiple
* times. But reuse_swap_page() might have removed the page
* from swapcache already, so we can't check PageSwapCache().
*/
if (!memcg)
return;
if (PageTransHuge(page)) {
nr_pages <<= compound_order(page);
VM_BUG_ON_PAGE(!PageTransHuge(page), page);
}
cancel_charge(memcg, nr_pages);
}
static void uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout,
unsigned long nr_anon, unsigned long nr_file,
unsigned long nr_huge, struct page *dummy_page)
{
unsigned long nr_pages = nr_anon + nr_file;
unsigned long flags;
if (!mem_cgroup_is_root(memcg)) {
page_counter_uncharge(&memcg->memory, nr_pages);
if (do_swap_account)
page_counter_uncharge(&memcg->memsw, nr_pages);
memcg_oom_recover(memcg);
}
local_irq_save(flags);
__this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS], nr_anon);
__this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_CACHE], nr_file);
__this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], nr_huge);
__this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT], pgpgout);
__this_cpu_add(memcg->stat->nr_page_events, nr_pages);
memcg_check_events(memcg, dummy_page);
local_irq_restore(flags);
if (!mem_cgroup_is_root(memcg))
css_put_many(&memcg->css, nr_pages);
}
static void uncharge_list(struct list_head *page_list)
{
struct mem_cgroup *memcg = NULL;
unsigned long nr_anon = 0;
unsigned long nr_file = 0;
unsigned long nr_huge = 0;
unsigned long pgpgout = 0;
struct list_head *next;
struct page *page;
next = page_list->next;
do {
unsigned int nr_pages = 1;
page = list_entry(next, struct page, lru);
next = page->lru.next;
VM_BUG_ON_PAGE(PageLRU(page), page);
VM_BUG_ON_PAGE(page_count(page), page);
if (!page->mem_cgroup)
continue;
/*
* Nobody should be changing or seriously looking at
* page->mem_cgroup at this point, we have fully
* exclusive access to the page.
*/
if (memcg != page->mem_cgroup) {
if (memcg) {
uncharge_batch(memcg, pgpgout, nr_anon, nr_file,
nr_huge, page);
pgpgout = nr_anon = nr_file = nr_huge = 0;
}
memcg = page->mem_cgroup;
}
if (PageTransHuge(page)) {
nr_pages <<= compound_order(page);
VM_BUG_ON_PAGE(!PageTransHuge(page), page);
nr_huge += nr_pages;
}
if (PageAnon(page))
nr_anon += nr_pages;
else
nr_file += nr_pages;
page->mem_cgroup = NULL;
pgpgout++;
} while (next != page_list);
if (memcg)
uncharge_batch(memcg, pgpgout, nr_anon, nr_file,
nr_huge, page);
}
/**
* mem_cgroup_uncharge - uncharge a page
* @page: page to uncharge
*
* Uncharge a page previously charged with mem_cgroup_try_charge() and
* mem_cgroup_commit_charge().
*/
void mem_cgroup_uncharge(struct page *page)
{
if (mem_cgroup_disabled())
return;
/* Don't touch page->lru of any random page, pre-check: */
if (!page->mem_cgroup)
return;
INIT_LIST_HEAD(&page->lru);
uncharge_list(&page->lru);
}
/**
* mem_cgroup_uncharge_list - uncharge a list of page
* @page_list: list of pages to uncharge
*
* Uncharge a list of pages previously charged with
* mem_cgroup_try_charge() and mem_cgroup_commit_charge().
*/
void mem_cgroup_uncharge_list(struct list_head *page_list)
{
if (mem_cgroup_disabled())
return;
if (!list_empty(page_list))
uncharge_list(page_list);
}
/**
* mem_cgroup_migrate - migrate a charge to another page
* @oldpage: currently charged page
* @newpage: page to transfer the charge to
* @lrucare: both pages might be on the LRU already
*
* Migrate the charge from @oldpage to @newpage.
*
* Both pages must be locked, @newpage->mapping must be set up.
*/
void mem_cgroup_migrate(struct page *oldpage, struct page *newpage,
bool lrucare)
{
struct mem_cgroup *memcg;
int isolated;
VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage);
VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
VM_BUG_ON_PAGE(!lrucare && PageLRU(oldpage), oldpage);
VM_BUG_ON_PAGE(!lrucare && PageLRU(newpage), newpage);
VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage);
VM_BUG_ON_PAGE(PageTransHuge(oldpage) != PageTransHuge(newpage),
newpage);
if (mem_cgroup_disabled())
return;
/* Page cache replacement: new page already charged? */
if (newpage->mem_cgroup)
return;
/*
* Swapcache readahead pages can get migrated before being
* charged, and migration from compaction can happen to an
* uncharged page when the PFN walker finds a page that
* reclaim just put back on the LRU but has not released yet.
*/
memcg = oldpage->mem_cgroup;
if (!memcg)
return;
if (lrucare)
lock_page_lru(oldpage, &isolated);
oldpage->mem_cgroup = NULL;
if (lrucare)
unlock_page_lru(oldpage, isolated);
commit_charge(newpage, memcg, lrucare);
}
/*
* subsys_initcall() for memory controller.
*
* Some parts like hotcpu_notifier() have to be initialized from this context
* because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
* everything that doesn't depend on a specific mem_cgroup structure should
* be initialized from here.
*/
static int __init mem_cgroup_init(void)
{
hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
enable_swap_cgroup();
mem_cgroup_soft_limit_tree_init();
memcg_stock_init();
return 0;
}
subsys_initcall(mem_cgroup_init);
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