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-rw-r--r--mm/memcontrol.c5626
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diff --git a/mm/memcontrol.c b/mm/memcontrol.c
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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
+ *
+ * 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/res_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/mutex.h>
+#include <linux/rbtree.h>
+#include <linux/shmem_fs.h>
+#include <linux/slab.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+#include <linux/spinlock.h>
+#include <linux/eventfd.h>
+#include <linux/sort.h>
+#include <linux/fs.h>
+#include <linux/seq_file.h>
+#include <linux/vmalloc.h>
+#include <linux/mm_inline.h>
+#include <linux/page_cgroup.h>
+#include <linux/cpu.h>
+#include <linux/oom.h>
+#include "internal.h"
+
+#include <asm/uaccess.h>
+
+#include <trace/events/vmscan.h>
+
+struct cgroup_subsys mem_cgroup_subsys __read_mostly;
+#define MEM_CGROUP_RECLAIM_RETRIES 5
+struct mem_cgroup *root_mem_cgroup __read_mostly;
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_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_CGROUP_MEM_RES_CTLR_SWAP_ENABLED
+static int really_do_swap_account __initdata = 1;
+#else
+static int really_do_swap_account __initdata = 0;
+#endif
+
+#else
+#define do_swap_account (0)
+#endif
+
+
+/*
+ * Statistics for memory cgroup.
+ */
+enum mem_cgroup_stat_index {
+ /*
+ * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
+ */
+ MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
+ MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */
+ MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
+ MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
+ MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */
+ MEM_CGROUP_ON_MOVE, /* someone is moving account between groups */
+ MEM_CGROUP_STAT_NSTATS,
+};
+
+enum mem_cgroup_events_index {
+ MEM_CGROUP_EVENTS_PGPGIN, /* # of pages paged in */
+ MEM_CGROUP_EVENTS_PGPGOUT, /* # of pages paged out */
+ MEM_CGROUP_EVENTS_COUNT, /* # of pages paged in/out */
+ MEM_CGROUP_EVENTS_PGFAULT, /* # of page-faults */
+ MEM_CGROUP_EVENTS_PGMAJFAULT, /* # of major page-faults */
+ MEM_CGROUP_EVENTS_NSTATS,
+};
+/*
+ * 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 targets[MEM_CGROUP_NTARGETS];
+};
+
+/*
+ * per-zone information in memory controller.
+ */
+struct mem_cgroup_per_zone {
+ /*
+ * spin_lock to protect the per cgroup LRU
+ */
+ struct list_head lists[NR_LRU_LISTS];
+ unsigned long count[NR_LRU_LISTS];
+
+ struct zone_reclaim_stat reclaim_stat;
+ struct rb_node tree_node; /* RB tree node */
+ unsigned long long usage_in_excess;/* Set to the value by which */
+ /* the soft limit is exceeded*/
+ bool on_tree;
+ struct mem_cgroup *mem; /* Back pointer, we cannot */
+ /* use container_of */
+};
+/* Macro for accessing counter */
+#define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)])
+
+struct mem_cgroup_per_node {
+ struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
+};
+
+struct mem_cgroup_lru_info {
+ struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES];
+};
+
+/*
+ * 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;
+ u64 threshold;
+};
+
+/* For threshold */
+struct mem_cgroup_threshold_ary {
+ /* An array index points to threshold just below 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;
+};
+
+static void mem_cgroup_threshold(struct mem_cgroup *mem);
+static void mem_cgroup_oom_notify(struct mem_cgroup *mem);
+
+/*
+ * 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;
+ /*
+ * the counter to account for memory usage
+ */
+ struct res_counter res;
+ /*
+ * the counter to account for mem+swap usage.
+ */
+ struct res_counter memsw;
+ /*
+ * Per cgroup active and inactive list, similar to the
+ * per zone LRU lists.
+ */
+ struct mem_cgroup_lru_info info;
+ /*
+ * While reclaiming in a hierarchy, we cache the last child we
+ * reclaimed from.
+ */
+ int last_scanned_child;
+ int last_scanned_node;
+#if MAX_NUMNODES > 1
+ nodemask_t scan_nodes;
+ atomic_t numainfo_events;
+ atomic_t numainfo_updating;
+#endif
+ /*
+ * Should the accounting and control be hierarchical, per subtree?
+ */
+ bool use_hierarchy;
+ atomic_t oom_lock;
+ atomic_t refcnt;
+
+ unsigned int swappiness;
+ /* OOM-Killer disable */
+ int oom_kill_disable;
+
+ /* set when res.limit == memsw.limit */
+ bool memsw_is_minimum;
+
+ /* 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;
+ /*
+ * percpu counter.
+ */
+ struct mem_cgroup_stat_cpu *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;
+};
+
+/* Stuffs for move charges at task migration. */
+/*
+ * Types of charges to be moved. "move_charge_at_immitgrate" is 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 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.to->move_charge_at_immigrate);
+}
+
+static bool move_file(void)
+{
+ return test_bit(MOVE_CHARGE_TYPE_FILE,
+ &mc.to->move_charge_at_immigrate);
+}
+
+/*
+ * 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_MAPPED,
+ MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */
+ MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
+ 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 */
+#define _MEM (0)
+#define _MEMSWAP (1)
+#define _OOM_TYPE (2)
+#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)
+
+/*
+ * Reclaim flags for mem_cgroup_hierarchical_reclaim
+ */
+#define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
+#define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
+#define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
+#define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
+#define MEM_CGROUP_RECLAIM_SOFT_BIT 0x2
+#define MEM_CGROUP_RECLAIM_SOFT (1 << MEM_CGROUP_RECLAIM_SOFT_BIT)
+
+static void mem_cgroup_get(struct mem_cgroup *mem);
+static void mem_cgroup_put(struct mem_cgroup *mem);
+static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
+static void drain_all_stock_async(struct mem_cgroup *mem);
+
+static struct mem_cgroup_per_zone *
+mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
+{
+ return &mem->info.nodeinfo[nid]->zoneinfo[zid];
+}
+
+struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem)
+{
+ return &mem->css;
+}
+
+static struct mem_cgroup_per_zone *
+page_cgroup_zoneinfo(struct mem_cgroup *mem, struct page *page)
+{
+ int nid = page_to_nid(page);
+ int zid = page_zonenum(page);
+
+ return mem_cgroup_zoneinfo(mem, nid, 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 *mem,
+ struct mem_cgroup_per_zone *mz,
+ struct mem_cgroup_tree_per_zone *mctz,
+ unsigned long 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 *mem,
+ 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 *mem,
+ struct mem_cgroup_per_zone *mz,
+ struct mem_cgroup_tree_per_zone *mctz)
+{
+ spin_lock(&mctz->lock);
+ __mem_cgroup_remove_exceeded(mem, mz, mctz);
+ spin_unlock(&mctz->lock);
+}
+
+
+static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
+{
+ unsigned long long excess;
+ struct mem_cgroup_per_zone *mz;
+ struct mem_cgroup_tree_per_zone *mctz;
+ int nid = page_to_nid(page);
+ int zid = page_zonenum(page);
+ mctz = soft_limit_tree_from_page(page);
+
+ /*
+ * Necessary to update all ancestors when hierarchy is used.
+ * because their event counter is not touched.
+ */
+ for (; mem; mem = parent_mem_cgroup(mem)) {
+ mz = mem_cgroup_zoneinfo(mem, nid, zid);
+ excess = res_counter_soft_limit_excess(&mem->res);
+ /*
+ * We have to update the tree if mz is on RB-tree or
+ * mem is over its softlimit.
+ */
+ if (excess || mz->on_tree) {
+ spin_lock(&mctz->lock);
+ /* if on-tree, remove it */
+ if (mz->on_tree)
+ __mem_cgroup_remove_exceeded(mem, mz, mctz);
+ /*
+ * Insert again. mz->usage_in_excess will be updated.
+ * If excess is 0, no tree ops.
+ */
+ __mem_cgroup_insert_exceeded(mem, mz, mctz, excess);
+ spin_unlock(&mctz->lock);
+ }
+ }
+}
+
+static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem)
+{
+ int node, zone;
+ struct mem_cgroup_per_zone *mz;
+ struct mem_cgroup_tree_per_zone *mctz;
+
+ for_each_node_state(node, N_POSSIBLE) {
+ for (zone = 0; zone < MAX_NR_ZONES; zone++) {
+ mz = mem_cgroup_zoneinfo(mem, node, zone);
+ mctz = soft_limit_tree_node_zone(node, zone);
+ mem_cgroup_remove_exceeded(mem, 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->mem, mz, mctz);
+ if (!res_counter_soft_limit_excess(&mz->mem->res) ||
+ !css_tryget(&mz->mem->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(&mctz->lock);
+ mz = __mem_cgroup_largest_soft_limit_node(mctz);
+ spin_unlock(&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 *mem,
+ enum mem_cgroup_stat_index idx)
+{
+ long val = 0;
+ int cpu;
+
+ get_online_cpus();
+ for_each_online_cpu(cpu)
+ val += per_cpu(mem->stat->count[idx], cpu);
+#ifdef CONFIG_HOTPLUG_CPU
+ spin_lock(&mem->pcp_counter_lock);
+ val += mem->nocpu_base.count[idx];
+ spin_unlock(&mem->pcp_counter_lock);
+#endif
+ put_online_cpus();
+ return val;
+}
+
+static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,
+ bool charge)
+{
+ int val = (charge) ? 1 : -1;
+ this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_SWAPOUT], val);
+}
+
+void mem_cgroup_pgfault(struct mem_cgroup *mem, int val)
+{
+ this_cpu_add(mem->stat->events[MEM_CGROUP_EVENTS_PGFAULT], val);
+}
+
+void mem_cgroup_pgmajfault(struct mem_cgroup *mem, int val)
+{
+ this_cpu_add(mem->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT], val);
+}
+
+static unsigned long mem_cgroup_read_events(struct mem_cgroup *mem,
+ enum mem_cgroup_events_index idx)
+{
+ unsigned long val = 0;
+ int cpu;
+
+ for_each_online_cpu(cpu)
+ val += per_cpu(mem->stat->events[idx], cpu);
+#ifdef CONFIG_HOTPLUG_CPU
+ spin_lock(&mem->pcp_counter_lock);
+ val += mem->nocpu_base.events[idx];
+ spin_unlock(&mem->pcp_counter_lock);
+#endif
+ return val;
+}
+
+static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
+ bool file, int nr_pages)
+{
+ preempt_disable();
+
+ if (file)
+ __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], nr_pages);
+ else
+ __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], nr_pages);
+
+ /* pagein of a big page is an event. So, ignore page size */
+ if (nr_pages > 0)
+ __this_cpu_inc(mem->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
+ else {
+ __this_cpu_inc(mem->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
+ nr_pages = -nr_pages; /* for event */
+ }
+
+ __this_cpu_add(mem->stat->events[MEM_CGROUP_EVENTS_COUNT], nr_pages);
+
+ preempt_enable();
+}
+
+static unsigned long
+mem_cgroup_get_zonestat_node(struct mem_cgroup *mem, int nid, enum lru_list idx)
+{
+ struct mem_cgroup_per_zone *mz;
+ u64 total = 0;
+ int zid;
+
+ for (zid = 0; zid < MAX_NR_ZONES; zid++) {
+ mz = mem_cgroup_zoneinfo(mem, nid, zid);
+ total += MEM_CGROUP_ZSTAT(mz, idx);
+ }
+ return total;
+}
+static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
+ enum lru_list idx)
+{
+ int nid;
+ u64 total = 0;
+
+ for_each_online_node(nid)
+ total += mem_cgroup_get_zonestat_node(mem, nid, idx);
+ return total;
+}
+
+static bool __memcg_event_check(struct mem_cgroup *mem, int target)
+{
+ unsigned long val, next;
+
+ val = this_cpu_read(mem->stat->events[MEM_CGROUP_EVENTS_COUNT]);
+ next = this_cpu_read(mem->stat->targets[target]);
+ /* from time_after() in jiffies.h */
+ return ((long)next - (long)val < 0);
+}
+
+static void __mem_cgroup_target_update(struct mem_cgroup *mem, int target)
+{
+ unsigned long val, next;
+
+ val = this_cpu_read(mem->stat->events[MEM_CGROUP_EVENTS_COUNT]);
+
+ 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:
+ return;
+ }
+
+ this_cpu_write(mem->stat->targets[target], next);
+}
+
+/*
+ * Check events in order.
+ *
+ */
+static void memcg_check_events(struct mem_cgroup *mem, struct page *page)
+{
+ /* threshold event is triggered in finer grain than soft limit */
+ if (unlikely(__memcg_event_check(mem, MEM_CGROUP_TARGET_THRESH))) {
+ mem_cgroup_threshold(mem);
+ __mem_cgroup_target_update(mem, MEM_CGROUP_TARGET_THRESH);
+ if (unlikely(__memcg_event_check(mem,
+ MEM_CGROUP_TARGET_SOFTLIMIT))) {
+ mem_cgroup_update_tree(mem, page);
+ __mem_cgroup_target_update(mem,
+ MEM_CGROUP_TARGET_SOFTLIMIT);
+ }
+#if MAX_NUMNODES > 1
+ if (unlikely(__memcg_event_check(mem,
+ MEM_CGROUP_TARGET_NUMAINFO))) {
+ atomic_inc(&mem->numainfo_events);
+ __mem_cgroup_target_update(mem,
+ MEM_CGROUP_TARGET_NUMAINFO);
+ }
+#endif
+ }
+}
+
+static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
+{
+ return container_of(cgroup_subsys_state(cont,
+ mem_cgroup_subsys_id), struct mem_cgroup,
+ css);
+}
+
+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 container_of(task_subsys_state(p, mem_cgroup_subsys_id),
+ struct mem_cgroup, css);
+}
+
+struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
+{
+ struct mem_cgroup *mem = NULL;
+
+ if (!mm)
+ return NULL;
+ /*
+ * Because we have no locks, mm->owner's may be being moved to other
+ * cgroup. We use css_tryget() here even if this looks
+ * pessimistic (rather than adding locks here).
+ */
+ rcu_read_lock();
+ do {
+ mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+ if (unlikely(!mem))
+ break;
+ } while (!css_tryget(&mem->css));
+ rcu_read_unlock();
+ return mem;
+}
+
+/* The caller has to guarantee "mem" exists before calling this */
+static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *mem)
+{
+ struct cgroup_subsys_state *css;
+ int found;
+
+ if (!mem) /* ROOT cgroup has the smallest ID */
+ return root_mem_cgroup; /*css_put/get against root is ignored*/
+ if (!mem->use_hierarchy) {
+ if (css_tryget(&mem->css))
+ return mem;
+ return NULL;
+ }
+ rcu_read_lock();
+ /*
+ * searching a memory cgroup which has the smallest ID under given
+ * ROOT cgroup. (ID >= 1)
+ */
+ css = css_get_next(&mem_cgroup_subsys, 1, &mem->css, &found);
+ if (css && css_tryget(css))
+ mem = container_of(css, struct mem_cgroup, css);
+ else
+ mem = NULL;
+ rcu_read_unlock();
+ return mem;
+}
+
+static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter,
+ struct mem_cgroup *root,
+ bool cond)
+{
+ int nextid = css_id(&iter->css) + 1;
+ int found;
+ int hierarchy_used;
+ struct cgroup_subsys_state *css;
+
+ hierarchy_used = iter->use_hierarchy;
+
+ css_put(&iter->css);
+ /* If no ROOT, walk all, ignore hierarchy */
+ if (!cond || (root && !hierarchy_used))
+ return NULL;
+
+ if (!root)
+ root = root_mem_cgroup;
+
+ do {
+ iter = NULL;
+ rcu_read_lock();
+
+ css = css_get_next(&mem_cgroup_subsys, nextid,
+ &root->css, &found);
+ if (css && css_tryget(css))
+ iter = container_of(css, struct mem_cgroup, css);
+ rcu_read_unlock();
+ /* If css is NULL, no more cgroups will be found */
+ nextid = found + 1;
+ } while (css && !iter);
+
+ return iter;
+}
+/*
+ * for_eacn_mem_cgroup_tree() for visiting all cgroup under tree. Please
+ * be careful that "break" loop is not allowed. We have reference count.
+ * Instead of that modify "cond" to be false and "continue" to exit the loop.
+ */
+#define for_each_mem_cgroup_tree_cond(iter, root, cond) \
+ for (iter = mem_cgroup_start_loop(root);\
+ iter != NULL;\
+ iter = mem_cgroup_get_next(iter, root, cond))
+
+#define for_each_mem_cgroup_tree(iter, root) \
+ for_each_mem_cgroup_tree_cond(iter, root, true)
+
+#define for_each_mem_cgroup_all(iter) \
+ for_each_mem_cgroup_tree_cond(iter, NULL, true)
+
+
+static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
+{
+ return (mem == root_mem_cgroup);
+}
+
+void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
+{
+ struct mem_cgroup *mem;
+
+ if (!mm)
+ return;
+
+ rcu_read_lock();
+ mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+ if (unlikely(!mem))
+ goto out;
+
+ switch (idx) {
+ case PGMAJFAULT:
+ mem_cgroup_pgmajfault(mem, 1);
+ break;
+ case PGFAULT:
+ mem_cgroup_pgfault(mem, 1);
+ break;
+ default:
+ BUG();
+ }
+out:
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL(mem_cgroup_count_vm_event);
+
+/*
+ * Following LRU functions are allowed to be used without PCG_LOCK.
+ * Operations are called by routine of global LRU independently from memcg.
+ * What we have to take care of here is validness of pc->mem_cgroup.
+ *
+ * Changes to pc->mem_cgroup happens when
+ * 1. charge
+ * 2. moving account
+ * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
+ * It is added to LRU before charge.
+ * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
+ * When moving account, the page is not on LRU. It's isolated.
+ */
+
+void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
+{
+ struct page_cgroup *pc;
+ struct mem_cgroup_per_zone *mz;
+
+ if (mem_cgroup_disabled())
+ return;
+ pc = lookup_page_cgroup(page);
+ /* can happen while we handle swapcache. */
+ if (!TestClearPageCgroupAcctLRU(pc))
+ return;
+ VM_BUG_ON(!pc->mem_cgroup);
+ /*
+ * We don't check PCG_USED bit. It's cleared when the "page" is finally
+ * removed from global LRU.
+ */
+ mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
+ /* huge page split is done under lru_lock. so, we have no races. */
+ MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page);
+ if (mem_cgroup_is_root(pc->mem_cgroup))
+ return;
+ VM_BUG_ON(list_empty(&pc->lru));
+ list_del_init(&pc->lru);
+}
+
+void mem_cgroup_del_lru(struct page *page)
+{
+ mem_cgroup_del_lru_list(page, page_lru(page));
+}
+
+/*
+ * Writeback is about to end against a page which has been marked for immediate
+ * reclaim. If it still appears to be reclaimable, move it to the tail of the
+ * inactive list.
+ */
+void mem_cgroup_rotate_reclaimable_page(struct page *page)
+{
+ struct mem_cgroup_per_zone *mz;
+ struct page_cgroup *pc;
+ enum lru_list lru = page_lru(page);
+
+ if (mem_cgroup_disabled())
+ return;
+
+ pc = lookup_page_cgroup(page);
+ /* unused or root page is not rotated. */
+ if (!PageCgroupUsed(pc))
+ return;
+ /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
+ smp_rmb();
+ if (mem_cgroup_is_root(pc->mem_cgroup))
+ return;
+ mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
+ list_move_tail(&pc->lru, &mz->lists[lru]);
+}
+
+void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
+{
+ struct mem_cgroup_per_zone *mz;
+ struct page_cgroup *pc;
+
+ if (mem_cgroup_disabled())
+ return;
+
+ pc = lookup_page_cgroup(page);
+ /* unused or root page is not rotated. */
+ if (!PageCgroupUsed(pc))
+ return;
+ /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
+ smp_rmb();
+ if (mem_cgroup_is_root(pc->mem_cgroup))
+ return;
+ mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
+ list_move(&pc->lru, &mz->lists[lru]);
+}
+
+void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
+{
+ struct page_cgroup *pc;
+ struct mem_cgroup_per_zone *mz;
+
+ if (mem_cgroup_disabled())
+ return;
+ pc = lookup_page_cgroup(page);
+ VM_BUG_ON(PageCgroupAcctLRU(pc));
+ if (!PageCgroupUsed(pc))
+ return;
+ /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
+ smp_rmb();
+ mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
+ /* huge page split is done under lru_lock. so, we have no races. */
+ MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page);
+ SetPageCgroupAcctLRU(pc);
+ if (mem_cgroup_is_root(pc->mem_cgroup))
+ return;
+ list_add(&pc->lru, &mz->lists[lru]);
+}
+
+/*
+ * At handling SwapCache and other FUSE stuff, pc->mem_cgroup may be changed
+ * while it's linked to lru because the page may be reused after it's fully
+ * uncharged. To handle that, unlink page_cgroup from LRU when charge it again.
+ * It's done under lock_page and expected that zone->lru_lock isnever held.
+ */
+static void mem_cgroup_lru_del_before_commit(struct page *page)
+{
+ unsigned long flags;
+ struct zone *zone = page_zone(page);
+ struct page_cgroup *pc = lookup_page_cgroup(page);
+
+ /*
+ * Doing this check without taking ->lru_lock seems wrong but this
+ * is safe. Because if page_cgroup's USED bit is unset, the page
+ * will not be added to any memcg's LRU. If page_cgroup's USED bit is
+ * set, the commit after this will fail, anyway.
+ * This all charge/uncharge is done under some mutual execustion.
+ * So, we don't need to taking care of changes in USED bit.
+ */
+ if (likely(!PageLRU(page)))
+ return;
+
+ spin_lock_irqsave(&zone->lru_lock, flags);
+ /*
+ * Forget old LRU when this page_cgroup is *not* used. This Used bit
+ * is guarded by lock_page() because the page is SwapCache.
+ */
+ if (!PageCgroupUsed(pc))
+ mem_cgroup_del_lru_list(page, page_lru(page));
+ spin_unlock_irqrestore(&zone->lru_lock, flags);
+}
+
+static void mem_cgroup_lru_add_after_commit(struct page *page)
+{
+ unsigned long flags;
+ struct zone *zone = page_zone(page);
+ struct page_cgroup *pc = lookup_page_cgroup(page);
+
+ /* taking care of that the page is added to LRU while we commit it */
+ if (likely(!PageLRU(page)))
+ return;
+ spin_lock_irqsave(&zone->lru_lock, flags);
+ /* link when the page is linked to LRU but page_cgroup isn't */
+ if (PageLRU(page) && !PageCgroupAcctLRU(pc))
+ mem_cgroup_add_lru_list(page, page_lru(page));
+ spin_unlock_irqrestore(&zone->lru_lock, flags);
+}
+
+
+void mem_cgroup_move_lists(struct page *page,
+ enum lru_list from, enum lru_list to)
+{
+ if (mem_cgroup_disabled())
+ return;
+ mem_cgroup_del_lru_list(page, from);
+ mem_cgroup_add_lru_list(page, to);
+}
+
+int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
+{
+ int ret;
+ struct mem_cgroup *curr = NULL;
+ struct task_struct *p;
+
+ p = find_lock_task_mm(task);
+ if (!p)
+ return 0;
+ curr = try_get_mem_cgroup_from_mm(p->mm);
+ task_unlock(p);
+ if (!curr)
+ return 0;
+ /*
+ * We should check use_hierarchy of "mem" not "curr". Because checking
+ * use_hierarchy of "curr" here make this function true if hierarchy is
+ * enabled in "curr" and "curr" is a child of "mem" in *cgroup*
+ * hierarchy(even if use_hierarchy is disabled in "mem").
+ */
+ if (mem->use_hierarchy)
+ ret = css_is_ancestor(&curr->css, &mem->css);
+ else
+ ret = (curr == mem);
+ css_put(&curr->css);
+ return ret;
+}
+
+static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
+{
+ unsigned long active;
+ unsigned long inactive;
+ unsigned long gb;
+ unsigned long inactive_ratio;
+
+ inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON);
+ active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON);
+
+ gb = (inactive + active) >> (30 - PAGE_SHIFT);
+ if (gb)
+ inactive_ratio = int_sqrt(10 * gb);
+ else
+ inactive_ratio = 1;
+
+ if (present_pages) {
+ present_pages[0] = inactive;
+ present_pages[1] = active;
+ }
+
+ return inactive_ratio;
+}
+
+int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
+{
+ unsigned long active;
+ unsigned long inactive;
+ unsigned long present_pages[2];
+ unsigned long inactive_ratio;
+
+ inactive_ratio = calc_inactive_ratio(memcg, present_pages);
+
+ inactive = present_pages[0];
+ active = present_pages[1];
+
+ if (inactive * inactive_ratio < active)
+ return 1;
+
+ return 0;
+}
+
+int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)
+{
+ unsigned long active;
+ unsigned long inactive;
+
+ inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_FILE);
+ active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_FILE);
+
+ return (active > inactive);
+}
+
+unsigned long mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg,
+ struct zone *zone,
+ enum lru_list lru)
+{
+ int nid = zone_to_nid(zone);
+ int zid = zone_idx(zone);
+ struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
+
+ return MEM_CGROUP_ZSTAT(mz, lru);
+}
+
+static unsigned long mem_cgroup_node_nr_file_lru_pages(struct mem_cgroup *memcg,
+ int nid)
+{
+ unsigned long ret;
+
+ ret = mem_cgroup_get_zonestat_node(memcg, nid, LRU_INACTIVE_FILE) +
+ mem_cgroup_get_zonestat_node(memcg, nid, LRU_ACTIVE_FILE);
+
+ return ret;
+}
+
+static unsigned long mem_cgroup_node_nr_anon_lru_pages(struct mem_cgroup *memcg,
+ int nid)
+{
+ unsigned long ret;
+
+ ret = mem_cgroup_get_zonestat_node(memcg, nid, LRU_INACTIVE_ANON) +
+ mem_cgroup_get_zonestat_node(memcg, nid, LRU_ACTIVE_ANON);
+ return ret;
+}
+
+#if MAX_NUMNODES > 1
+static unsigned long mem_cgroup_nr_file_lru_pages(struct mem_cgroup *memcg)
+{
+ u64 total = 0;
+ int nid;
+
+ for_each_node_state(nid, N_HIGH_MEMORY)
+ total += mem_cgroup_node_nr_file_lru_pages(memcg, nid);
+
+ return total;
+}
+
+static unsigned long mem_cgroup_nr_anon_lru_pages(struct mem_cgroup *memcg)
+{
+ u64 total = 0;
+ int nid;
+
+ for_each_node_state(nid, N_HIGH_MEMORY)
+ total += mem_cgroup_node_nr_anon_lru_pages(memcg, nid);
+
+ return total;
+}
+
+static unsigned long
+mem_cgroup_node_nr_unevictable_lru_pages(struct mem_cgroup *memcg, int nid)
+{
+ return mem_cgroup_get_zonestat_node(memcg, nid, LRU_UNEVICTABLE);
+}
+
+static unsigned long
+mem_cgroup_nr_unevictable_lru_pages(struct mem_cgroup *memcg)
+{
+ u64 total = 0;
+ int nid;
+
+ for_each_node_state(nid, N_HIGH_MEMORY)
+ total += mem_cgroup_node_nr_unevictable_lru_pages(memcg, nid);
+
+ return total;
+}
+
+static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
+ int nid)
+{
+ enum lru_list l;
+ u64 total = 0;
+
+ for_each_lru(l)
+ total += mem_cgroup_get_zonestat_node(memcg, nid, l);
+
+ return total;
+}
+
+static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg)
+{
+ u64 total = 0;
+ int nid;
+
+ for_each_node_state(nid, N_HIGH_MEMORY)
+ total += mem_cgroup_node_nr_lru_pages(memcg, nid);
+
+ return total;
+}
+#endif /* CONFIG_NUMA */
+
+struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
+ struct zone *zone)
+{
+ int nid = zone_to_nid(zone);
+ int zid = zone_idx(zone);
+ struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
+
+ return &mz->reclaim_stat;
+}
+
+struct zone_reclaim_stat *
+mem_cgroup_get_reclaim_stat_from_page(struct page *page)
+{
+ struct page_cgroup *pc;
+ struct mem_cgroup_per_zone *mz;
+
+ if (mem_cgroup_disabled())
+ return NULL;
+
+ pc = lookup_page_cgroup(page);
+ if (!PageCgroupUsed(pc))
+ return NULL;
+ /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
+ smp_rmb();
+ mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
+ return &mz->reclaim_stat;
+}
+
+unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
+ struct list_head *dst,
+ unsigned long *scanned, int order,
+ int mode, struct zone *z,
+ struct mem_cgroup *mem_cont,
+ int active, int file)
+{
+ unsigned long nr_taken = 0;
+ struct page *page;
+ unsigned long scan;
+ LIST_HEAD(pc_list);
+ struct list_head *src;
+ struct page_cgroup *pc, *tmp;
+ int nid = zone_to_nid(z);
+ int zid = zone_idx(z);
+ struct mem_cgroup_per_zone *mz;
+ int lru = LRU_FILE * file + active;
+ int ret;
+
+ BUG_ON(!mem_cont);
+ mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
+ src = &mz->lists[lru];
+
+ scan = 0;
+ list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
+ if (scan >= nr_to_scan)
+ break;
+
+ if (unlikely(!PageCgroupUsed(pc)))
+ continue;
+
+ page = lookup_cgroup_page(pc);
+
+ if (unlikely(!PageLRU(page)))
+ continue;
+
+ scan++;
+ ret = __isolate_lru_page(page, mode, file);
+ switch (ret) {
+ case 0:
+ list_move(&page->lru, dst);
+ mem_cgroup_del_lru(page);
+ nr_taken += hpage_nr_pages(page);
+ break;
+ case -EBUSY:
+ /* we don't affect global LRU but rotate in our LRU */
+ mem_cgroup_rotate_lru_list(page, page_lru(page));
+ break;
+ default:
+ break;
+ }
+ }
+
+ *scanned = scan;
+
+ trace_mm_vmscan_memcg_isolate(0, nr_to_scan, scan, nr_taken,
+ 0, 0, 0, mode);
+
+ return nr_taken;
+}
+
+#define mem_cgroup_from_res_counter(counter, member) \
+ container_of(counter, struct mem_cgroup, member)
+
+/**
+ * mem_cgroup_margin - calculate chargeable space of a memory cgroup
+ * @mem: 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 *mem)
+{
+ unsigned long long margin;
+
+ margin = res_counter_margin(&mem->res);
+ if (do_swap_account)
+ margin = min(margin, res_counter_margin(&mem->memsw));
+ return margin >> PAGE_SHIFT;
+}
+
+static unsigned int get_swappiness(struct mem_cgroup *memcg)
+{
+ struct cgroup *cgrp = memcg->css.cgroup;
+
+ /* root ? */
+ if (cgrp->parent == NULL)
+ return vm_swappiness;
+
+ return memcg->swappiness;
+}
+
+static void mem_cgroup_start_move(struct mem_cgroup *mem)
+{
+ int cpu;
+
+ get_online_cpus();
+ spin_lock(&mem->pcp_counter_lock);
+ for_each_online_cpu(cpu)
+ per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1;
+ mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1;
+ spin_unlock(&mem->pcp_counter_lock);
+ put_online_cpus();
+
+ synchronize_rcu();
+}
+
+static void mem_cgroup_end_move(struct mem_cgroup *mem)
+{
+ int cpu;
+
+ if (!mem)
+ return;
+ get_online_cpus();
+ spin_lock(&mem->pcp_counter_lock);
+ for_each_online_cpu(cpu)
+ per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1;
+ mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1;
+ spin_unlock(&mem->pcp_counter_lock);
+ put_online_cpus();
+}
+/*
+ * 2 routines for checking "mem" is under move_account() or not.
+ *
+ * mem_cgroup_stealed() - checking a cgroup is mc.from or not. This is used
+ * for avoiding race in accounting. If true,
+ * pc->mem_cgroup may be overwritten.
+ *
+ * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
+ * under hierarchy of moving cgroups. This is for
+ * waiting at hith-memory prressure caused by "move".
+ */
+
+static bool mem_cgroup_stealed(struct mem_cgroup *mem)
+{
+ VM_BUG_ON(!rcu_read_lock_held());
+ return this_cpu_read(mem->stat->count[MEM_CGROUP_ON_MOVE]) > 0;
+}
+
+static bool mem_cgroup_under_move(struct mem_cgroup *mem)
+{
+ 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;
+ if (from == mem || to == mem
+ || (mem->use_hierarchy && css_is_ancestor(&from->css, &mem->css))
+ || (mem->use_hierarchy && css_is_ancestor(&to->css, &mem->css)))
+ ret = true;
+unlock:
+ spin_unlock(&mc.lock);
+ return ret;
+}
+
+static bool mem_cgroup_wait_acct_move(struct mem_cgroup *mem)
+{
+ if (mc.moving_task && current != mc.moving_task) {
+ if (mem_cgroup_under_move(mem)) {
+ 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;
+}
+
+/**
+ * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
+ * @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)
+{
+ struct cgroup *task_cgrp;
+ struct cgroup *mem_cgrp;
+ /*
+ * Need a buffer in BSS, can't rely on allocations. The code relies
+ * on the assumption that OOM is serialized for memory controller.
+ * If this assumption is broken, revisit this code.
+ */
+ static char memcg_name[PATH_MAX];
+ int ret;
+
+ if (!memcg || !p)
+ return;
+
+
+ rcu_read_lock();
+
+ mem_cgrp = memcg->css.cgroup;
+ task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
+
+ ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
+ if (ret < 0) {
+ /*
+ * Unfortunately, we are unable to convert to a useful name
+ * But we'll still print out the usage information
+ */
+ rcu_read_unlock();
+ goto done;
+ }
+ rcu_read_unlock();
+
+ printk(KERN_INFO "Task in %s killed", memcg_name);
+
+ rcu_read_lock();
+ ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
+ if (ret < 0) {
+ rcu_read_unlock();
+ goto done;
+ }
+ rcu_read_unlock();
+
+ /*
+ * Continues from above, so we don't need an KERN_ level
+ */
+ printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
+done:
+
+ printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
+ res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
+ res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
+ res_counter_read_u64(&memcg->res, RES_FAILCNT));
+ printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
+ "failcnt %llu\n",
+ res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
+ res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
+ res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
+}
+
+/*
+ * 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 *mem)
+{
+ int num = 0;
+ struct mem_cgroup *iter;
+
+ for_each_mem_cgroup_tree(iter, mem)
+ num++;
+ return num;
+}
+
+/*
+ * Return the memory (and swap, if configured) limit for a memcg.
+ */
+u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
+{
+ u64 limit;
+ u64 memsw;
+
+ limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
+ limit += total_swap_pages << PAGE_SHIFT;
+
+ memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
+ /*
+ * If memsw is finite and limits the amount of swap space available
+ * to this memcg, return that limit.
+ */
+ return min(limit, memsw);
+}
+
+/*
+ * Visit the first child (need not be the first child as per the ordering
+ * of the cgroup list, since we track last_scanned_child) of @mem and use
+ * that to reclaim free pages from.
+ */
+static struct mem_cgroup *
+mem_cgroup_select_victim(struct mem_cgroup *root_mem)
+{
+ struct mem_cgroup *ret = NULL;
+ struct cgroup_subsys_state *css;
+ int nextid, found;
+
+ if (!root_mem->use_hierarchy) {
+ css_get(&root_mem->css);
+ ret = root_mem;
+ }
+
+ while (!ret) {
+ rcu_read_lock();
+ nextid = root_mem->last_scanned_child + 1;
+ css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
+ &found);
+ if (css && css_tryget(css))
+ ret = container_of(css, struct mem_cgroup, css);
+
+ rcu_read_unlock();
+ /* Updates scanning parameter */
+ if (!css) {
+ /* this means start scan from ID:1 */
+ root_mem->last_scanned_child = 0;
+ } else
+ root_mem->last_scanned_child = found;
+ }
+
+ return ret;
+}
+
+/**
+ * test_mem_cgroup_node_reclaimable
+ * @mem: 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 *mem,
+ int nid, bool noswap)
+{
+ if (mem_cgroup_node_nr_file_lru_pages(mem, nid))
+ return true;
+ if (noswap || !total_swap_pages)
+ return false;
+ if (mem_cgroup_node_nr_anon_lru_pages(mem, nid))
+ return true;
+ return false;
+
+}
+#if MAX_NUMNODES > 1
+
+/*
+ * 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 *mem)
+{
+ int nid;
+ /*
+ * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
+ * pagein/pageout changes since the last update.
+ */
+ if (!atomic_read(&mem->numainfo_events))
+ return;
+ if (atomic_inc_return(&mem->numainfo_updating) > 1)
+ return;
+
+ /* make a nodemask where this memcg uses memory from */
+ mem->scan_nodes = node_states[N_HIGH_MEMORY];
+
+ for_each_node_mask(nid, node_states[N_HIGH_MEMORY]) {
+
+ if (!test_mem_cgroup_node_reclaimable(mem, nid, false))
+ node_clear(nid, mem->scan_nodes);
+ }
+
+ atomic_set(&mem->numainfo_events, 0);
+ atomic_set(&mem->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 *mem)
+{
+ int node;
+
+ mem_cgroup_may_update_nodemask(mem);
+ node = mem->last_scanned_node;
+
+ node = next_node(node, mem->scan_nodes);
+ if (node == MAX_NUMNODES)
+ node = first_node(mem->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();
+
+ mem->last_scanned_node = node;
+ return node;
+}
+
+/*
+ * Check all nodes whether it contains reclaimable pages or not.
+ * For quick scan, we make use of scan_nodes. This will allow us to skip
+ * unused nodes. But scan_nodes is lazily updated and may not cotain
+ * enough new information. We need to do double check.
+ */
+bool mem_cgroup_reclaimable(struct mem_cgroup *mem, bool noswap)
+{
+ int nid;
+
+ /*
+ * quick check...making use of scan_node.
+ * We can skip unused nodes.
+ */
+ if (!nodes_empty(mem->scan_nodes)) {
+ for (nid = first_node(mem->scan_nodes);
+ nid < MAX_NUMNODES;
+ nid = next_node(nid, mem->scan_nodes)) {
+
+ if (test_mem_cgroup_node_reclaimable(mem, nid, noswap))
+ return true;
+ }
+ }
+ /*
+ * Check rest of nodes.
+ */
+ for_each_node_state(nid, N_HIGH_MEMORY) {
+ if (node_isset(nid, mem->scan_nodes))
+ continue;
+ if (test_mem_cgroup_node_reclaimable(mem, nid, noswap))
+ return true;
+ }
+ return false;
+}
+
+#else
+int mem_cgroup_select_victim_node(struct mem_cgroup *mem)
+{
+ return 0;
+}
+
+bool mem_cgroup_reclaimable(struct mem_cgroup *mem, bool noswap)
+{
+ return test_mem_cgroup_node_reclaimable(mem, 0, noswap);
+}
+#endif
+
+/*
+ * Scan the hierarchy if needed to reclaim memory. We remember the last child
+ * we reclaimed from, so that we don't end up penalizing one child extensively
+ * based on its position in the children list.
+ *
+ * root_mem is the original ancestor that we've been reclaim from.
+ *
+ * We give up and return to the caller when we visit root_mem twice.
+ * (other groups can be removed while we're walking....)
+ *
+ * If shrink==true, for avoiding to free too much, this returns immedieately.
+ */
+static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
+ struct zone *zone,
+ gfp_t gfp_mask,
+ unsigned long reclaim_options,
+ unsigned long *total_scanned)
+{
+ struct mem_cgroup *victim;
+ int ret, total = 0;
+ int loop = 0;
+ bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
+ bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
+ bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
+ unsigned long excess;
+ unsigned long nr_scanned;
+
+ excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT;
+
+ /* If memsw_is_minimum==1, swap-out is of-no-use. */
+ if (!check_soft && !shrink && root_mem->memsw_is_minimum)
+ noswap = true;
+
+ while (1) {
+ victim = mem_cgroup_select_victim(root_mem);
+ if (victim == root_mem) {
+ loop++;
+ /*
+ * We are not draining per cpu cached charges during
+ * soft limit reclaim because global reclaim doesn't
+ * care about charges. It tries to free some memory and
+ * charges will not give any.
+ */
+ if (!check_soft && loop >= 1)
+ drain_all_stock_async(root_mem);
+ if (loop >= 2) {
+ /*
+ * If we have not been able to reclaim
+ * anything, it might because there are
+ * no reclaimable pages under this hierarchy
+ */
+ if (!check_soft || !total) {
+ css_put(&victim->css);
+ 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)) {
+ css_put(&victim->css);
+ break;
+ }
+ }
+ }
+ if (!mem_cgroup_reclaimable(victim, noswap)) {
+ /* this cgroup's local usage == 0 */
+ css_put(&victim->css);
+ continue;
+ }
+ /* we use swappiness of local cgroup */
+ if (check_soft) {
+ ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
+ noswap, get_swappiness(victim), zone,
+ &nr_scanned);
+ *total_scanned += nr_scanned;
+ } else
+ ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
+ noswap, get_swappiness(victim));
+ css_put(&victim->css);
+ /*
+ * At shrinking usage, we can't check we should stop here or
+ * reclaim more. It's depends on callers. last_scanned_child
+ * will work enough for keeping fairness under tree.
+ */
+ if (shrink)
+ return ret;
+ total += ret;
+ if (check_soft) {
+ if (!res_counter_soft_limit_excess(&root_mem->res))
+ return total;
+ } else if (mem_cgroup_margin(root_mem))
+ return total;
+ }
+ return total;
+}
+
+/*
+ * Check OOM-Killer is already running under our hierarchy.
+ * If someone is running, return false.
+ */
+static bool mem_cgroup_oom_lock(struct mem_cgroup *mem)
+{
+ int x, lock_count = 0;
+ struct mem_cgroup *iter;
+
+ for_each_mem_cgroup_tree(iter, mem) {
+ x = atomic_inc_return(&iter->oom_lock);
+ lock_count = max(x, lock_count);
+ }
+
+ if (lock_count == 1)
+ return true;
+ return false;
+}
+
+static int mem_cgroup_oom_unlock(struct mem_cgroup *mem)
+{
+ 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, mem)
+ atomic_add_unless(&iter->oom_lock, -1, 0);
+ return 0;
+}
+
+
+static DEFINE_MUTEX(memcg_oom_mutex);
+static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
+
+struct oom_wait_info {
+ struct mem_cgroup *mem;
+ wait_queue_t wait;
+};
+
+static int memcg_oom_wake_function(wait_queue_t *wait,
+ unsigned mode, int sync, void *arg)
+{
+ struct mem_cgroup *wake_mem = (struct mem_cgroup *)arg;
+ struct oom_wait_info *oom_wait_info;
+
+ oom_wait_info = container_of(wait, struct oom_wait_info, wait);
+
+ if (oom_wait_info->mem == wake_mem)
+ goto wakeup;
+ /* if no hierarchy, no match */
+ if (!oom_wait_info->mem->use_hierarchy || !wake_mem->use_hierarchy)
+ return 0;
+ /*
+ * Both of oom_wait_info->mem and wake_mem are stable under us.
+ * Then we can use css_is_ancestor without taking care of RCU.
+ */
+ if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) &&
+ !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css))
+ return 0;
+
+wakeup:
+ return autoremove_wake_function(wait, mode, sync, arg);
+}
+
+static void memcg_wakeup_oom(struct mem_cgroup *mem)
+{
+ /* for filtering, pass "mem" as argument. */
+ __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, mem);
+}
+
+static void memcg_oom_recover(struct mem_cgroup *mem)
+{
+ if (mem && atomic_read(&mem->oom_lock))
+ memcg_wakeup_oom(mem);
+}
+
+/*
+ * try to call OOM killer. returns false if we should exit memory-reclaim loop.
+ */
+bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask)
+{
+ struct oom_wait_info owait;
+ bool locked, need_to_kill;
+
+ owait.mem = mem;
+ owait.wait.flags = 0;
+ owait.wait.func = memcg_oom_wake_function;
+ owait.wait.private = current;
+ INIT_LIST_HEAD(&owait.wait.task_list);
+ need_to_kill = true;
+ /* At first, try to OOM lock hierarchy under mem.*/
+ mutex_lock(&memcg_oom_mutex);
+ locked = mem_cgroup_oom_lock(mem);
+ /*
+ * Even if signal_pending(), we can't quit charge() loop without
+ * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
+ * under OOM is always welcomed, use TASK_KILLABLE here.
+ */
+ prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
+ if (!locked || mem->oom_kill_disable)
+ need_to_kill = false;
+ if (locked)
+ mem_cgroup_oom_notify(mem);
+ mutex_unlock(&memcg_oom_mutex);
+
+ if (need_to_kill) {
+ finish_wait(&memcg_oom_waitq, &owait.wait);
+ mem_cgroup_out_of_memory(mem, mask);
+ } else {
+ schedule();
+ finish_wait(&memcg_oom_waitq, &owait.wait);
+ }
+ mutex_lock(&memcg_oom_mutex);
+ mem_cgroup_oom_unlock(mem);
+ memcg_wakeup_oom(mem);
+ mutex_unlock(&memcg_oom_mutex);
+
+ if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current))
+ return false;
+ /* Give chance to dying process */
+ schedule_timeout(1);
+ return true;
+}
+
+/*
+ * Currently used to update mapped file statistics, but the routine can be
+ * generalized to update other statistics as well.
+ *
+ * Notes: Race condition
+ *
+ * We usually use page_cgroup_lock() for accessing page_cgroup member but
+ * it tends to be costly. But considering some conditions, we doesn't need
+ * to do so _always_.
+ *
+ * Considering "charge", lock_page_cgroup() is not required because all
+ * file-stat operations happen after a page is attached to radix-tree. There
+ * are no race with "charge".
+ *
+ * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
+ * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
+ * if there are race with "uncharge". Statistics itself is properly handled
+ * by flags.
+ *
+ * Considering "move", this is an only case we see a race. To make the race
+ * small, we check MEM_CGROUP_ON_MOVE percpu value and detect there are
+ * possibility of race condition. If there is, we take a lock.
+ */
+
+void mem_cgroup_update_page_stat(struct page *page,
+ enum mem_cgroup_page_stat_item idx, int val)
+{
+ struct mem_cgroup *mem;
+ struct page_cgroup *pc = lookup_page_cgroup(page);
+ bool need_unlock = false;
+ unsigned long uninitialized_var(flags);
+
+ if (unlikely(!pc))
+ return;
+
+ rcu_read_lock();
+ mem = pc->mem_cgroup;
+ if (unlikely(!mem || !PageCgroupUsed(pc)))
+ goto out;
+ /* pc->mem_cgroup is unstable ? */
+ if (unlikely(mem_cgroup_stealed(mem)) || PageTransHuge(page)) {
+ /* take a lock against to access pc->mem_cgroup */
+ move_lock_page_cgroup(pc, &flags);
+ need_unlock = true;
+ mem = pc->mem_cgroup;
+ if (!mem || !PageCgroupUsed(pc))
+ goto out;
+ }
+
+ switch (idx) {
+ case MEMCG_NR_FILE_MAPPED:
+ if (val > 0)
+ SetPageCgroupFileMapped(pc);
+ else if (!page_mapped(page))
+ ClearPageCgroupFileMapped(pc);
+ idx = MEM_CGROUP_STAT_FILE_MAPPED;
+ break;
+ default:
+ BUG();
+ }
+
+ this_cpu_add(mem->stat->count[idx], val);
+
+out:
+ if (unlikely(need_unlock))
+ move_unlock_page_cgroup(pc, &flags);
+ rcu_read_unlock();
+ return;
+}
+EXPORT_SYMBOL(mem_cgroup_update_page_stat);
+
+/*
+ * 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);
+
+/*
+ * Try to consume stocked charge on this cpu. If success, one page is consumed
+ * from local stock and true is returned. If the stock is 0 or charges from a
+ * cgroup which is not current target, returns false. This stock will be
+ * refilled.
+ */
+static bool consume_stock(struct mem_cgroup *mem)
+{
+ struct memcg_stock_pcp *stock;
+ bool ret = true;
+
+ stock = &get_cpu_var(memcg_stock);
+ if (mem == stock->cached && stock->nr_pages)
+ stock->nr_pages--;
+ else /* need to call res_counter_charge */
+ ret = false;
+ put_cpu_var(memcg_stock);
+ return ret;
+}
+
+/*
+ * Returns stocks cached in percpu to res_counter and reset cached information.
+ */
+static void drain_stock(struct memcg_stock_pcp *stock)
+{
+ struct mem_cgroup *old = stock->cached;
+
+ if (stock->nr_pages) {
+ unsigned long bytes = stock->nr_pages * PAGE_SIZE;
+
+ res_counter_uncharge(&old->res, bytes);
+ if (do_swap_account)
+ res_counter_uncharge(&old->memsw, bytes);
+ 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 = &__get_cpu_var(memcg_stock);
+ drain_stock(stock);
+ clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
+}
+
+/*
+ * Cache charges(val) which is from res_counter, to local per_cpu area.
+ * This will be consumed by consume_stock() function, later.
+ */
+static void refill_stock(struct mem_cgroup *mem, unsigned int nr_pages)
+{
+ struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
+
+ if (stock->cached != mem) { /* reset if necessary */
+ drain_stock(stock);
+ stock->cached = mem;
+ }
+ stock->nr_pages += nr_pages;
+ put_cpu_var(memcg_stock);
+}
+
+/*
+ * Tries to drain stocked charges in other cpus. This function is asynchronous
+ * and just put a work per cpu for draining localy on each cpu. Caller can
+ * expects some charges will be back to res_counter later but cannot wait for
+ * it.
+ */
+static void drain_all_stock_async(struct mem_cgroup *root_mem)
+{
+ int cpu, curcpu;
+ /*
+ * If someone calls draining, avoid adding more kworker runs.
+ */
+ if (!mutex_trylock(&percpu_charge_mutex))
+ return;
+ /* Notify other cpus that system-wide "drain" is running */
+ get_online_cpus();
+ /*
+ * Get a hint for avoiding draining charges on the current cpu,
+ * which must be exhausted by our charging. It is not required that
+ * this be a precise check, so we use raw_smp_processor_id() instead of
+ * getcpu()/putcpu().
+ */
+ curcpu = raw_smp_processor_id();
+ for_each_online_cpu(cpu) {
+ struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
+ struct mem_cgroup *mem;
+
+ if (cpu == curcpu)
+ continue;
+
+ mem = stock->cached;
+ if (!mem)
+ continue;
+ if (mem != root_mem) {
+ if (!root_mem->use_hierarchy)
+ continue;
+ /* check whether "mem" is under tree of "root_mem" */
+ if (!css_is_ancestor(&mem->css, &root_mem->css))
+ continue;
+ }
+ if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
+ schedule_work_on(cpu, &stock->work);
+ }
+ put_online_cpus();
+ mutex_unlock(&percpu_charge_mutex);
+ /* We don't wait for flush_work */
+}
+
+/* This is a synchronous drain interface. */
+static void drain_all_stock_sync(void)
+{
+ /* called when force_empty is called */
+ mutex_lock(&percpu_charge_mutex);
+ schedule_on_each_cpu(drain_local_stock);
+ 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 *mem, int cpu)
+{
+ int i;
+
+ spin_lock(&mem->pcp_counter_lock);
+ for (i = 0; i < MEM_CGROUP_STAT_DATA; i++) {
+ long x = per_cpu(mem->stat->count[i], cpu);
+
+ per_cpu(mem->stat->count[i], cpu) = 0;
+ mem->nocpu_base.count[i] += x;
+ }
+ for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
+ unsigned long x = per_cpu(mem->stat->events[i], cpu);
+
+ per_cpu(mem->stat->events[i], cpu) = 0;
+ mem->nocpu_base.events[i] += x;
+ }
+ /* need to clear ON_MOVE value, works as a kind of lock. */
+ per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) = 0;
+ spin_unlock(&mem->pcp_counter_lock);
+}
+
+static void synchronize_mem_cgroup_on_move(struct mem_cgroup *mem, int cpu)
+{
+ int idx = MEM_CGROUP_ON_MOVE;
+
+ spin_lock(&mem->pcp_counter_lock);
+ per_cpu(mem->stat->count[idx], cpu) = mem->nocpu_base.count[idx];
+ spin_unlock(&mem->pcp_counter_lock);
+}
+
+static int __cpuinit 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)) {
+ for_each_mem_cgroup_all(iter)
+ synchronize_mem_cgroup_on_move(iter, cpu);
+ return NOTIFY_OK;
+ }
+
+ if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN)
+ return NOTIFY_OK;
+
+ for_each_mem_cgroup_all(iter)
+ mem_cgroup_drain_pcp_counter(iter, cpu);
+
+ stock = &per_cpu(memcg_stock, cpu);
+ drain_stock(stock);
+ return NOTIFY_OK;
+}
+
+
+/* See __mem_cgroup_try_charge() for details */
+enum {
+ CHARGE_OK, /* success */
+ CHARGE_RETRY, /* need to retry but retry is not bad */
+ CHARGE_NOMEM, /* we can't do more. return -ENOMEM */
+ CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */
+ CHARGE_OOM_DIE, /* the current is killed because of OOM */
+};
+
+static int mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask,
+ unsigned int nr_pages, bool oom_check)
+{
+ unsigned long csize = nr_pages * PAGE_SIZE;
+ struct mem_cgroup *mem_over_limit;
+ struct res_counter *fail_res;
+ unsigned long flags = 0;
+ int ret;
+
+ ret = res_counter_charge(&mem->res, csize, &fail_res);
+
+ if (likely(!ret)) {
+ if (!do_swap_account)
+ return CHARGE_OK;
+ ret = res_counter_charge(&mem->memsw, csize, &fail_res);
+ if (likely(!ret))
+ return CHARGE_OK;
+
+ res_counter_uncharge(&mem->res, csize);
+ mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
+ flags |= MEM_CGROUP_RECLAIM_NOSWAP;
+ } else
+ mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
+ /*
+ * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch
+ * of regular pages (CHARGE_BATCH), or a single regular page (1).
+ *
+ * Never reclaim on behalf of optional batching, retry with a
+ * single page instead.
+ */
+ if (nr_pages == CHARGE_BATCH)
+ return CHARGE_RETRY;
+
+ if (!(gfp_mask & __GFP_WAIT))
+ return CHARGE_WOULDBLOCK;
+
+ ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
+ gfp_mask, flags, NULL);
+ if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
+ return CHARGE_RETRY;
+ /*
+ * 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_pages == 1 && ret)
+ return CHARGE_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))
+ return CHARGE_RETRY;
+
+ /* If we don't need to call oom-killer at el, return immediately */
+ if (!oom_check)
+ return CHARGE_NOMEM;
+ /* check OOM */
+ if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask))
+ return CHARGE_OOM_DIE;
+
+ return CHARGE_RETRY;
+}
+
+/*
+ * Unlike exported interface, "oom" parameter is added. if oom==true,
+ * oom-killer can be invoked.
+ */
+static int __mem_cgroup_try_charge(struct mm_struct *mm,
+ gfp_t gfp_mask,
+ unsigned int nr_pages,
+ struct mem_cgroup **memcg,
+ bool oom)
+{
+ unsigned int batch = max(CHARGE_BATCH, nr_pages);
+ int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
+ struct mem_cgroup *mem = NULL;
+ int ret;
+
+ /*
+ * Unlike gloval-vm's OOM-kill, we're not in memory shortage
+ * in system level. So, allow to go ahead dying process in addition to
+ * MEMDIE process.
+ */
+ if (unlikely(test_thread_flag(TIF_MEMDIE)
+ || fatal_signal_pending(current)))
+ goto bypass;
+
+ /*
+ * We always charge the cgroup the mm_struct belongs to.
+ * The mm_struct's mem_cgroup changes on task migration if the
+ * thread group leader migrates. It's possible that mm is not
+ * set, if so charge the init_mm (happens for pagecache usage).
+ */
+ if (!*memcg && !mm)
+ goto bypass;
+again:
+ if (*memcg) { /* css should be a valid one */
+ mem = *memcg;
+ VM_BUG_ON(css_is_removed(&mem->css));
+ if (mem_cgroup_is_root(mem))
+ goto done;
+ if (nr_pages == 1 && consume_stock(mem))
+ goto done;
+ css_get(&mem->css);
+ } else {
+ struct task_struct *p;
+
+ rcu_read_lock();
+ p = rcu_dereference(mm->owner);
+ /*
+ * Because we don't have task_lock(), "p" can exit.
+ * In that case, "mem" can point to root or p can be NULL with
+ * race with swapoff. Then, we have small risk of mis-accouning.
+ * But such kind of mis-account by race always happens because
+ * we don't have cgroup_mutex(). It's overkill and we allo that
+ * small race, here.
+ * (*) swapoff at el will charge against mm-struct not against
+ * task-struct. So, mm->owner can be NULL.
+ */
+ mem = mem_cgroup_from_task(p);
+ if (!mem || mem_cgroup_is_root(mem)) {
+ rcu_read_unlock();
+ goto done;
+ }
+ if (nr_pages == 1 && consume_stock(mem)) {
+ /*
+ * It seems dagerous to access memcg without css_get().
+ * But considering how consume_stok works, it's not
+ * necessary. If consume_stock success, some charges
+ * from this memcg are cached on this cpu. So, we
+ * don't need to call css_get()/css_tryget() before
+ * calling consume_stock().
+ */
+ rcu_read_unlock();
+ goto done;
+ }
+ /* after here, we may be blocked. we need to get refcnt */
+ if (!css_tryget(&mem->css)) {
+ rcu_read_unlock();
+ goto again;
+ }
+ rcu_read_unlock();
+ }
+
+ do {
+ bool oom_check;
+
+ /* If killed, bypass charge */
+ if (fatal_signal_pending(current)) {
+ css_put(&mem->css);
+ goto bypass;
+ }
+
+ oom_check = false;
+ if (oom && !nr_oom_retries) {
+ oom_check = true;
+ nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
+ }
+
+ ret = mem_cgroup_do_charge(mem, gfp_mask, batch, oom_check);
+ switch (ret) {
+ case CHARGE_OK:
+ break;
+ case CHARGE_RETRY: /* not in OOM situation but retry */
+ batch = nr_pages;
+ css_put(&mem->css);
+ mem = NULL;
+ goto again;
+ case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
+ css_put(&mem->css);
+ goto nomem;
+ case CHARGE_NOMEM: /* OOM routine works */
+ if (!oom) {
+ css_put(&mem->css);
+ goto nomem;
+ }
+ /* If oom, we never return -ENOMEM */
+ nr_oom_retries--;
+ break;
+ case CHARGE_OOM_DIE: /* Killed by OOM Killer */
+ css_put(&mem->css);
+ goto bypass;
+ }
+ } while (ret != CHARGE_OK);
+
+ if (batch > nr_pages)
+ refill_stock(mem, batch - nr_pages);
+ css_put(&mem->css);
+done:
+ *memcg = mem;
+ return 0;
+nomem:
+ *memcg = NULL;
+ return -ENOMEM;
+bypass:
+ *memcg = NULL;
+ return 0;
+}
+
+/*
+ * Somemtimes we have to undo a charge we got by try_charge().
+ * This function is for that and do uncharge, put css's refcnt.
+ * gotten by try_charge().
+ */
+static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem,
+ unsigned int nr_pages)
+{
+ if (!mem_cgroup_is_root(mem)) {
+ unsigned long bytes = nr_pages * PAGE_SIZE;
+
+ res_counter_uncharge(&mem->res, bytes);
+ if (do_swap_account)
+ res_counter_uncharge(&mem->memsw, bytes);
+ }
+}
+
+/*
+ * A helper function to get mem_cgroup from ID. must be called under
+ * rcu_read_lock(). The caller must check css_is_removed() or some if
+ * it's concern. (dropping refcnt from swap can be called against removed
+ * memcg.)
+ */
+static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
+{
+ struct cgroup_subsys_state *css;
+
+ /* ID 0 is unused ID */
+ if (!id)
+ return NULL;
+ css = css_lookup(&mem_cgroup_subsys, id);
+ if (!css)
+ return NULL;
+ return container_of(css, struct mem_cgroup, css);
+}
+
+struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
+{
+ struct mem_cgroup *mem = NULL;
+ struct page_cgroup *pc;
+ unsigned short id;
+ swp_entry_t ent;
+
+ VM_BUG_ON(!PageLocked(page));
+
+ pc = lookup_page_cgroup(page);
+ lock_page_cgroup(pc);
+ if (PageCgroupUsed(pc)) {
+ mem = pc->mem_cgroup;
+ if (mem && !css_tryget(&mem->css))
+ mem = NULL;
+ } else if (PageSwapCache(page)) {
+ ent.val = page_private(page);
+ id = lookup_swap_cgroup(ent);
+ rcu_read_lock();
+ mem = mem_cgroup_lookup(id);
+ if (mem && !css_tryget(&mem->css))
+ mem = NULL;
+ rcu_read_unlock();
+ }
+ unlock_page_cgroup(pc);
+ return mem;
+}
+
+static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
+ struct page *page,
+ unsigned int nr_pages,
+ struct page_cgroup *pc,
+ enum charge_type ctype)
+{
+ lock_page_cgroup(pc);
+ if (unlikely(PageCgroupUsed(pc))) {
+ unlock_page_cgroup(pc);
+ __mem_cgroup_cancel_charge(mem, nr_pages);
+ return;
+ }
+ /*
+ * we don't need page_cgroup_lock about tail pages, becase they are not
+ * accessed by any other context at this point.
+ */
+ pc->mem_cgroup = mem;
+ /*
+ * We access a page_cgroup asynchronously without lock_page_cgroup().
+ * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
+ * is accessed after testing USED bit. To make pc->mem_cgroup visible
+ * before USED bit, we need memory barrier here.
+ * See mem_cgroup_add_lru_list(), etc.
+ */
+ smp_wmb();
+ switch (ctype) {
+ case MEM_CGROUP_CHARGE_TYPE_CACHE:
+ case MEM_CGROUP_CHARGE_TYPE_SHMEM:
+ SetPageCgroupCache(pc);
+ SetPageCgroupUsed(pc);
+ break;
+ case MEM_CGROUP_CHARGE_TYPE_MAPPED:
+ ClearPageCgroupCache(pc);
+ SetPageCgroupUsed(pc);
+ break;
+ default:
+ break;
+ }
+
+ mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), nr_pages);
+ unlock_page_cgroup(pc);
+ /*
+ * "charge_statistics" updated event counter. Then, check it.
+ * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
+ * if they exceeds softlimit.
+ */
+ memcg_check_events(mem, page);
+}
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+
+#define PCGF_NOCOPY_AT_SPLIT ((1 << PCG_LOCK) | (1 << PCG_MOVE_LOCK) |\
+ (1 << PCG_ACCT_LRU) | (1 << PCG_MIGRATION))
+/*
+ * Because tail pages are not marked as "used", set it. We're under
+ * zone->lru_lock, 'splitting on pmd' and compund_lock.
+ */
+void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail)
+{
+ struct page_cgroup *head_pc = lookup_page_cgroup(head);
+ struct page_cgroup *tail_pc = lookup_page_cgroup(tail);
+ unsigned long flags;
+
+ if (mem_cgroup_disabled())
+ return;
+ /*
+ * We have no races with charge/uncharge but will have races with
+ * page state accounting.
+ */
+ move_lock_page_cgroup(head_pc, &flags);
+
+ tail_pc->mem_cgroup = head_pc->mem_cgroup;
+ smp_wmb(); /* see __commit_charge() */
+ if (PageCgroupAcctLRU(head_pc)) {
+ enum lru_list lru;
+ struct mem_cgroup_per_zone *mz;
+
+ /*
+ * LRU flags cannot be copied because we need to add tail
+ *.page to LRU by generic call and our hook will be called.
+ * We hold lru_lock, then, reduce counter directly.
+ */
+ lru = page_lru(head);
+ mz = page_cgroup_zoneinfo(head_pc->mem_cgroup, head);
+ MEM_CGROUP_ZSTAT(mz, lru) -= 1;
+ }
+ tail_pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
+ move_unlock_page_cgroup(head_pc, &flags);
+}
+#endif
+
+/**
+ * mem_cgroup_move_account - move account of the page
+ * @page: the page
+ * @nr_pages: number of regular pages (>1 for huge pages)
+ * @pc: page_cgroup of the page.
+ * @from: mem_cgroup which the page is moved from.
+ * @to: mem_cgroup which the page is moved to. @from != @to.
+ * @uncharge: whether we should call uncharge and css_put against @from.
+ *
+ * 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" nor css_get to new cgroup. It should be
+ * done by a caller(__mem_cgroup_try_charge would be useful). If @uncharge is
+ * true, this function does "uncharge" from old cgroup, but it doesn't if
+ * @uncharge is false, so a caller should do "uncharge".
+ */
+static int mem_cgroup_move_account(struct page *page,
+ unsigned int nr_pages,
+ struct page_cgroup *pc,
+ struct mem_cgroup *from,
+ struct mem_cgroup *to,
+ bool uncharge)
+{
+ unsigned long flags;
+ int ret;
+
+ VM_BUG_ON(from == to);
+ VM_BUG_ON(PageLRU(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;
+
+ lock_page_cgroup(pc);
+
+ ret = -EINVAL;
+ if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
+ goto unlock;
+
+ move_lock_page_cgroup(pc, &flags);
+
+ if (PageCgroupFileMapped(pc)) {
+ /* Update mapped_file data for mem_cgroup */
+ preempt_disable();
+ __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
+ __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
+ preempt_enable();
+ }
+ mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages);
+ if (uncharge)
+ /* This is not "cancel", but cancel_charge does all we need. */
+ __mem_cgroup_cancel_charge(from, nr_pages);
+
+ /* caller should have done css_get */
+ pc->mem_cgroup = to;
+ mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages);
+ /*
+ * We charges against "to" which may not have any tasks. Then, "to"
+ * can be under rmdir(). But in current implementation, caller of
+ * this function is just force_empty() and move charge, so it's
+ * guaranteed that "to" is never removed. So, we don't check rmdir
+ * status here.
+ */
+ move_unlock_page_cgroup(pc, &flags);
+ ret = 0;
+unlock:
+ unlock_page_cgroup(pc);
+ /*
+ * check events
+ */
+ memcg_check_events(to, page);
+ memcg_check_events(from, page);
+out:
+ return ret;
+}
+
+/*
+ * move charges to its parent.
+ */
+
+static int mem_cgroup_move_parent(struct page *page,
+ struct page_cgroup *pc,
+ struct mem_cgroup *child,
+ gfp_t gfp_mask)
+{
+ struct cgroup *cg = child->css.cgroup;
+ struct cgroup *pcg = cg->parent;
+ struct mem_cgroup *parent;
+ unsigned int nr_pages;
+ unsigned long uninitialized_var(flags);
+ int ret;
+
+ /* Is ROOT ? */
+ if (!pcg)
+ return -EINVAL;
+
+ ret = -EBUSY;
+ if (!get_page_unless_zero(page))
+ goto out;
+ if (isolate_lru_page(page))
+ goto put;
+
+ nr_pages = hpage_nr_pages(page);
+
+ parent = mem_cgroup_from_cont(pcg);
+ ret = __mem_cgroup_try_charge(NULL, gfp_mask, nr_pages, &parent, false);
+ if (ret || !parent)
+ goto put_back;
+
+ if (nr_pages > 1)
+ flags = compound_lock_irqsave(page);
+
+ ret = mem_cgroup_move_account(page, nr_pages, pc, child, parent, true);
+ if (ret)
+ __mem_cgroup_cancel_charge(parent, nr_pages);
+
+ if (nr_pages > 1)
+ compound_unlock_irqrestore(page, flags);
+put_back:
+ putback_lru_page(page);
+put:
+ put_page(page);
+out:
+ return ret;
+}
+
+/*
+ * Charge the memory controller for page usage.
+ * Return
+ * 0 if the charge was successful
+ * < 0 if the cgroup is over its limit
+ */
+static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
+ gfp_t gfp_mask, enum charge_type ctype)
+{
+ struct mem_cgroup *mem = NULL;
+ unsigned int nr_pages = 1;
+ struct page_cgroup *pc;
+ bool oom = true;
+ int ret;
+
+ if (PageTransHuge(page)) {
+ nr_pages <<= compound_order(page);
+ VM_BUG_ON(!PageTransHuge(page));
+ /*
+ * Never OOM-kill a process for a huge page. The
+ * fault handler will fall back to regular pages.
+ */
+ oom = false;
+ }
+
+ pc = lookup_page_cgroup(page);
+ BUG_ON(!pc); /* XXX: remove this and move pc lookup into commit */
+
+ ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &mem, oom);
+ if (ret || !mem)
+ return ret;
+
+ __mem_cgroup_commit_charge(mem, page, nr_pages, pc, ctype);
+ return 0;
+}
+
+int mem_cgroup_newpage_charge(struct page *page,
+ struct mm_struct *mm, gfp_t gfp_mask)
+{
+ if (mem_cgroup_disabled())
+ return 0;
+ /*
+ * If already mapped, we don't have to account.
+ * If page cache, page->mapping has address_space.
+ * But page->mapping may have out-of-use anon_vma pointer,
+ * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
+ * is NULL.
+ */
+ if (page_mapped(page) || (page->mapping && !PageAnon(page)))
+ return 0;
+ if (unlikely(!mm))
+ mm = &init_mm;
+ return mem_cgroup_charge_common(page, mm, gfp_mask,
+ MEM_CGROUP_CHARGE_TYPE_MAPPED);
+}
+
+static void
+__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
+ enum charge_type ctype);
+
+static void
+__mem_cgroup_commit_charge_lrucare(struct page *page, struct mem_cgroup *mem,
+ enum charge_type ctype)
+{
+ struct page_cgroup *pc = lookup_page_cgroup(page);
+ /*
+ * In some case, SwapCache, FUSE(splice_buf->radixtree), the page
+ * is already on LRU. It means the page may on some other page_cgroup's
+ * LRU. Take care of it.
+ */
+ mem_cgroup_lru_del_before_commit(page);
+ __mem_cgroup_commit_charge(mem, page, 1, pc, ctype);
+ mem_cgroup_lru_add_after_commit(page);
+ return;
+}
+
+int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
+ gfp_t gfp_mask)
+{
+ struct mem_cgroup *mem = NULL;
+ int ret;
+
+ if (mem_cgroup_disabled())
+ return 0;
+ if (PageCompound(page))
+ return 0;
+ /*
+ * Corner case handling. This is called from add_to_page_cache()
+ * in usual. But some FS (shmem) precharges this page before calling it
+ * and call add_to_page_cache() with GFP_NOWAIT.
+ *
+ * For GFP_NOWAIT case, the page may be pre-charged before calling
+ * add_to_page_cache(). (See shmem.c) check it here and avoid to call
+ * charge twice. (It works but has to pay a bit larger cost.)
+ * And when the page is SwapCache, it should take swap information
+ * into account. This is under lock_page() now.
+ */
+ if (!(gfp_mask & __GFP_WAIT)) {
+ struct page_cgroup *pc;
+
+ pc = lookup_page_cgroup(page);
+ if (!pc)
+ return 0;
+ lock_page_cgroup(pc);
+ if (PageCgroupUsed(pc)) {
+ unlock_page_cgroup(pc);
+ return 0;
+ }
+ unlock_page_cgroup(pc);
+ }
+
+ if (unlikely(!mm))
+ mm = &init_mm;
+
+ if (page_is_file_cache(page)) {
+ ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, &mem, true);
+ if (ret || !mem)
+ return ret;
+
+ /*
+ * FUSE reuses pages without going through the final
+ * put that would remove them from the LRU list, make
+ * sure that they get relinked properly.
+ */
+ __mem_cgroup_commit_charge_lrucare(page, mem,
+ MEM_CGROUP_CHARGE_TYPE_CACHE);
+ return ret;
+ }
+ /* shmem */
+ if (PageSwapCache(page)) {
+ ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
+ if (!ret)
+ __mem_cgroup_commit_charge_swapin(page, mem,
+ MEM_CGROUP_CHARGE_TYPE_SHMEM);
+ } else
+ ret = mem_cgroup_charge_common(page, mm, gfp_mask,
+ MEM_CGROUP_CHARGE_TYPE_SHMEM);
+
+ return ret;
+}
+
+/*
+ * While swap-in, try_charge -> commit or cancel, the page is locked.
+ * And when try_charge() successfully returns, one refcnt to memcg without
+ * struct page_cgroup is acquired. This refcnt will be consumed by
+ * "commit()" or removed by "cancel()"
+ */
+int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
+ struct page *page,
+ gfp_t mask, struct mem_cgroup **ptr)
+{
+ struct mem_cgroup *mem;
+ int ret;
+
+ *ptr = NULL;
+
+ if (mem_cgroup_disabled())
+ return 0;
+
+ if (!do_swap_account)
+ goto charge_cur_mm;
+ /*
+ * A racing thread's fault, or swapoff, may have already updated
+ * the pte, and even removed page from swap cache: in those cases
+ * do_swap_page()'s pte_same() test will fail; but there's also a
+ * KSM case which does need to charge the page.
+ */
+ if (!PageSwapCache(page))
+ goto charge_cur_mm;
+ mem = try_get_mem_cgroup_from_page(page);
+ if (!mem)
+ goto charge_cur_mm;
+ *ptr = mem;
+ ret = __mem_cgroup_try_charge(NULL, mask, 1, ptr, true);
+ css_put(&mem->css);
+ return ret;
+charge_cur_mm:
+ if (unlikely(!mm))
+ mm = &init_mm;
+ return __mem_cgroup_try_charge(mm, mask, 1, ptr, true);
+}
+
+static void
+__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
+ enum charge_type ctype)
+{
+ if (mem_cgroup_disabled())
+ return;
+ if (!ptr)
+ return;
+ cgroup_exclude_rmdir(&ptr->css);
+
+ __mem_cgroup_commit_charge_lrucare(page, ptr, ctype);
+ /*
+ * Now swap is on-memory. This means this page may be
+ * counted both as mem and swap....double count.
+ * Fix it by uncharging from memsw. Basically, this SwapCache is stable
+ * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
+ * may call delete_from_swap_cache() before reach here.
+ */
+ if (do_swap_account && PageSwapCache(page)) {
+ swp_entry_t ent = {.val = page_private(page)};
+ unsigned short id;
+ struct mem_cgroup *memcg;
+
+ id = swap_cgroup_record(ent, 0);
+ rcu_read_lock();
+ memcg = mem_cgroup_lookup(id);
+ if (memcg) {
+ /*
+ * This recorded memcg can be obsolete one. So, avoid
+ * calling css_tryget
+ */
+ if (!mem_cgroup_is_root(memcg))
+ res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
+ mem_cgroup_swap_statistics(memcg, false);
+ mem_cgroup_put(memcg);
+ }
+ rcu_read_unlock();
+ }
+ /*
+ * At swapin, we may charge account against cgroup which has no tasks.
+ * So, rmdir()->pre_destroy() can be called while we do this charge.
+ * In that case, we need to call pre_destroy() again. check it here.
+ */
+ cgroup_release_and_wakeup_rmdir(&ptr->css);
+}
+
+void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
+{
+ __mem_cgroup_commit_charge_swapin(page, ptr,
+ MEM_CGROUP_CHARGE_TYPE_MAPPED);
+}
+
+void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
+{
+ if (mem_cgroup_disabled())
+ return;
+ if (!mem)
+ return;
+ __mem_cgroup_cancel_charge(mem, 1);
+}
+
+static void mem_cgroup_do_uncharge(struct mem_cgroup *mem,
+ unsigned int nr_pages,
+ const enum charge_type ctype)
+{
+ struct memcg_batch_info *batch = NULL;
+ bool uncharge_memsw = true;
+
+ /* If swapout, usage of swap doesn't decrease */
+ if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
+ uncharge_memsw = false;
+
+ batch = &current->memcg_batch;
+ /*
+ * In usual, we do css_get() when we remember memcg pointer.
+ * But in this case, we keep res->usage until end of a series of
+ * uncharges. Then, it's ok to ignore memcg's refcnt.
+ */
+ if (!batch->memcg)
+ batch->memcg = mem;
+ /*
+ * do_batch > 0 when unmapping pages or inode invalidate/truncate.
+ * In those cases, all pages freed continuously can be expected to be in
+ * the same cgroup and we have chance to coalesce uncharges.
+ * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
+ * because we want to do uncharge as soon as possible.
+ */
+
+ if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
+ goto direct_uncharge;
+
+ if (nr_pages > 1)
+ goto direct_uncharge;
+
+ /*
+ * In typical case, batch->memcg == mem. This means we can
+ * merge a series of uncharges to an uncharge of res_counter.
+ * If not, we uncharge res_counter ony by one.
+ */
+ if (batch->memcg != mem)
+ goto direct_uncharge;
+ /* remember freed charge and uncharge it later */
+ batch->nr_pages++;
+ if (uncharge_memsw)
+ batch->memsw_nr_pages++;
+ return;
+direct_uncharge:
+ res_counter_uncharge(&mem->res, nr_pages * PAGE_SIZE);
+ if (uncharge_memsw)
+ res_counter_uncharge(&mem->memsw, nr_pages * PAGE_SIZE);
+ if (unlikely(batch->memcg != mem))
+ memcg_oom_recover(mem);
+ return;
+}
+
+/*
+ * uncharge if !page_mapped(page)
+ */
+static struct mem_cgroup *
+__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
+{
+ struct mem_cgroup *mem = NULL;
+ unsigned int nr_pages = 1;
+ struct page_cgroup *pc;
+
+ if (mem_cgroup_disabled())
+ return NULL;
+
+ if (PageSwapCache(page))
+ return NULL;
+
+ if (PageTransHuge(page)) {
+ nr_pages <<= compound_order(page);
+ VM_BUG_ON(!PageTransHuge(page));
+ }
+ /*
+ * Check if our page_cgroup is valid
+ */
+ pc = lookup_page_cgroup(page);
+ if (unlikely(!pc || !PageCgroupUsed(pc)))
+ return NULL;
+
+ lock_page_cgroup(pc);
+
+ mem = pc->mem_cgroup;
+
+ if (!PageCgroupUsed(pc))
+ goto unlock_out;
+
+ switch (ctype) {
+ case MEM_CGROUP_CHARGE_TYPE_MAPPED:
+ case MEM_CGROUP_CHARGE_TYPE_DROP:
+ /* See mem_cgroup_prepare_migration() */
+ if (page_mapped(page) || PageCgroupMigration(pc))
+ goto unlock_out;
+ break;
+ case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
+ if (!PageAnon(page)) { /* Shared memory */
+ if (page->mapping && !page_is_file_cache(page))
+ goto unlock_out;
+ } else if (page_mapped(page)) /* Anon */
+ goto unlock_out;
+ break;
+ default:
+ break;
+ }
+
+ mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), -nr_pages);
+
+ ClearPageCgroupUsed(pc);
+ /*
+ * pc->mem_cgroup is not cleared here. It will be accessed when it's
+ * freed from LRU. This is safe because uncharged page is expected not
+ * to be reused (freed soon). Exception is SwapCache, it's handled by
+ * special functions.
+ */
+
+ unlock_page_cgroup(pc);
+ /*
+ * even after unlock, we have mem->res.usage here and this memcg
+ * will never be freed.
+ */
+ memcg_check_events(mem, page);
+ if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
+ mem_cgroup_swap_statistics(mem, true);
+ mem_cgroup_get(mem);
+ }
+ if (!mem_cgroup_is_root(mem))
+ mem_cgroup_do_uncharge(mem, nr_pages, ctype);
+
+ return mem;
+
+unlock_out:
+ unlock_page_cgroup(pc);
+ return NULL;
+}
+
+void mem_cgroup_uncharge_page(struct page *page)
+{
+ /* early check. */
+ if (page_mapped(page))
+ return;
+ if (page->mapping && !PageAnon(page))
+ return;
+ __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
+}
+
+void mem_cgroup_uncharge_cache_page(struct page *page)
+{
+ VM_BUG_ON(page_mapped(page));
+ VM_BUG_ON(page->mapping);
+ __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
+}
+
+/*
+ * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
+ * In that cases, pages are freed continuously and we can expect pages
+ * are in the same memcg. All these calls itself limits the number of
+ * pages freed at once, then uncharge_start/end() is called properly.
+ * This may be called prural(2) times in a context,
+ */
+
+void mem_cgroup_uncharge_start(void)
+{
+ current->memcg_batch.do_batch++;
+ /* We can do nest. */
+ if (current->memcg_batch.do_batch == 1) {
+ current->memcg_batch.memcg = NULL;
+ current->memcg_batch.nr_pages = 0;
+ current->memcg_batch.memsw_nr_pages = 0;
+ }
+}
+
+void mem_cgroup_uncharge_end(void)
+{
+ struct memcg_batch_info *batch = &current->memcg_batch;
+
+ if (!batch->do_batch)
+ return;
+
+ batch->do_batch--;
+ if (batch->do_batch) /* If stacked, do nothing. */
+ return;
+
+ if (!batch->memcg)
+ return;
+ /*
+ * This "batch->memcg" is valid without any css_get/put etc...
+ * bacause we hide charges behind us.
+ */
+ if (batch->nr_pages)
+ res_counter_uncharge(&batch->memcg->res,
+ batch->nr_pages * PAGE_SIZE);
+ if (batch->memsw_nr_pages)
+ res_counter_uncharge(&batch->memcg->memsw,
+ batch->memsw_nr_pages * PAGE_SIZE);
+ memcg_oom_recover(batch->memcg);
+ /* forget this pointer (for sanity check) */
+ batch->memcg = NULL;
+}
+
+#ifdef CONFIG_SWAP
+/*
+ * called after __delete_from_swap_cache() and drop "page" account.
+ * memcg information is recorded to swap_cgroup of "ent"
+ */
+void
+mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
+{
+ struct mem_cgroup *memcg;
+ int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
+
+ if (!swapout) /* this was a swap cache but the swap is unused ! */
+ ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
+
+ memcg = __mem_cgroup_uncharge_common(page, ctype);
+
+ /*
+ * record memcg information, if swapout && memcg != NULL,
+ * mem_cgroup_get() was called in uncharge().
+ */
+ if (do_swap_account && swapout && memcg)
+ swap_cgroup_record(ent, css_id(&memcg->css));
+}
+#endif
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+/*
+ * called from swap_entry_free(). remove record in swap_cgroup and
+ * uncharge "memsw" account.
+ */
+void mem_cgroup_uncharge_swap(swp_entry_t ent)
+{
+ struct mem_cgroup *memcg;
+ unsigned short id;
+
+ if (!do_swap_account)
+ return;
+
+ id = swap_cgroup_record(ent, 0);
+ rcu_read_lock();
+ memcg = mem_cgroup_lookup(id);
+ if (memcg) {
+ /*
+ * We uncharge this because swap is freed.
+ * This memcg can be obsolete one. We avoid calling css_tryget
+ */
+ if (!mem_cgroup_is_root(memcg))
+ res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
+ mem_cgroup_swap_statistics(memcg, false);
+ mem_cgroup_put(memcg);
+ }
+ rcu_read_unlock();
+}
+
+/**
+ * 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
+ * @need_fixup: whether we should fixup res_counters and refcounts.
+ *
+ * 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 res_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, bool need_fixup)
+{
+ unsigned short old_id, new_id;
+
+ old_id = css_id(&from->css);
+ new_id = css_id(&to->css);
+
+ 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 res_counter and refcount handling till the end
+ * of task migration(mem_cgroup_clear_mc()) for performance
+ * improvement. But we cannot postpone mem_cgroup_get(to)
+ * because if the process that has been moved to @to does
+ * swap-in, the refcount of @to might be decreased to 0.
+ */
+ mem_cgroup_get(to);
+ if (need_fixup) {
+ if (!mem_cgroup_is_root(from))
+ res_counter_uncharge(&from->memsw, PAGE_SIZE);
+ mem_cgroup_put(from);
+ /*
+ * we charged both to->res and to->memsw, so we should
+ * uncharge to->res.
+ */
+ if (!mem_cgroup_is_root(to))
+ res_counter_uncharge(&to->res, PAGE_SIZE);
+ }
+ 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, bool need_fixup)
+{
+ return -EINVAL;
+}
+#endif
+
+/*
+ * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
+ * page belongs to.
+ */
+int mem_cgroup_prepare_migration(struct page *page,
+ struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask)
+{
+ struct mem_cgroup *mem = NULL;
+ struct page_cgroup *pc;
+ enum charge_type ctype;
+ int ret = 0;
+
+ *ptr = NULL;
+
+ VM_BUG_ON(PageTransHuge(page));
+ if (mem_cgroup_disabled())
+ return 0;
+
+ pc = lookup_page_cgroup(page);
+ lock_page_cgroup(pc);
+ if (PageCgroupUsed(pc)) {
+ mem = pc->mem_cgroup;
+ css_get(&mem->css);
+ /*
+ * At migrating an anonymous page, its mapcount goes down
+ * to 0 and uncharge() will be called. But, even if it's fully
+ * unmapped, migration may fail and this page has to be
+ * charged again. We set MIGRATION flag here and delay uncharge
+ * until end_migration() is called
+ *
+ * Corner Case Thinking
+ * A)
+ * When the old page was mapped as Anon and it's unmap-and-freed
+ * while migration was ongoing.
+ * If unmap finds the old page, uncharge() of it will be delayed
+ * until end_migration(). If unmap finds a new page, it's
+ * uncharged when it make mapcount to be 1->0. If unmap code
+ * finds swap_migration_entry, the new page will not be mapped
+ * and end_migration() will find it(mapcount==0).
+ *
+ * B)
+ * When the old page was mapped but migraion fails, the kernel
+ * remaps it. A charge for it is kept by MIGRATION flag even
+ * if mapcount goes down to 0. We can do remap successfully
+ * without charging it again.
+ *
+ * C)
+ * The "old" page is under lock_page() until the end of
+ * migration, so, the old page itself will not be swapped-out.
+ * If the new page is swapped out before end_migraton, our
+ * hook to usual swap-out path will catch the event.
+ */
+ if (PageAnon(page))
+ SetPageCgroupMigration(pc);
+ }
+ unlock_page_cgroup(pc);
+ /*
+ * If the page is not charged at this point,
+ * we return here.
+ */
+ if (!mem)
+ return 0;
+
+ *ptr = mem;
+ ret = __mem_cgroup_try_charge(NULL, gfp_mask, 1, ptr, false);
+ css_put(&mem->css);/* drop extra refcnt */
+ if (ret || *ptr == NULL) {
+ if (PageAnon(page)) {
+ lock_page_cgroup(pc);
+ ClearPageCgroupMigration(pc);
+ unlock_page_cgroup(pc);
+ /*
+ * The old page may be fully unmapped while we kept it.
+ */
+ mem_cgroup_uncharge_page(page);
+ }
+ return -ENOMEM;
+ }
+ /*
+ * We charge new page before it's used/mapped. So, even if unlock_page()
+ * is called before end_migration, we can catch all events on this new
+ * page. In the case new page is migrated but not remapped, new page's
+ * mapcount will be finally 0 and we call uncharge in end_migration().
+ */
+ pc = lookup_page_cgroup(newpage);
+ if (PageAnon(page))
+ ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
+ else if (page_is_file_cache(page))
+ ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
+ else
+ ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
+ __mem_cgroup_commit_charge(mem, page, 1, pc, ctype);
+ return ret;
+}
+
+/* remove redundant charge if migration failed*/
+void mem_cgroup_end_migration(struct mem_cgroup *mem,
+ struct page *oldpage, struct page *newpage, bool migration_ok)
+{
+ struct page *used, *unused;
+ struct page_cgroup *pc;
+
+ if (!mem)
+ return;
+ /* blocks rmdir() */
+ cgroup_exclude_rmdir(&mem->css);
+ if (!migration_ok) {
+ used = oldpage;
+ unused = newpage;
+ } else {
+ used = newpage;
+ unused = oldpage;
+ }
+ /*
+ * We disallowed uncharge of pages under migration because mapcount
+ * of the page goes down to zero, temporarly.
+ * Clear the flag and check the page should be charged.
+ */
+ pc = lookup_page_cgroup(oldpage);
+ lock_page_cgroup(pc);
+ ClearPageCgroupMigration(pc);
+ unlock_page_cgroup(pc);
+
+ __mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);
+
+ /*
+ * If a page is a file cache, radix-tree replacement is very atomic
+ * and we can skip this check. When it was an Anon page, its mapcount
+ * goes down to 0. But because we added MIGRATION flage, it's not
+ * uncharged yet. There are several case but page->mapcount check
+ * and USED bit check in mem_cgroup_uncharge_page() will do enough
+ * check. (see prepare_charge() also)
+ */
+ if (PageAnon(used))
+ mem_cgroup_uncharge_page(used);
+ /*
+ * At migration, we may charge account against cgroup which has no
+ * tasks.
+ * So, rmdir()->pre_destroy() can be called while we do this charge.
+ * In that case, we need to call pre_destroy() again. check it here.
+ */
+ cgroup_release_and_wakeup_rmdir(&mem->css);
+}
+
+/*
+ * A call to try to shrink memory usage on charge failure at shmem's swapin.
+ * Calling hierarchical_reclaim is not enough because we should update
+ * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM.
+ * Moreover considering hierarchy, we should reclaim from the mem_over_limit,
+ * not from the memcg which this page would be charged to.
+ * try_charge_swapin does all of these works properly.
+ */
+int mem_cgroup_shmem_charge_fallback(struct page *page,
+ struct mm_struct *mm,
+ gfp_t gfp_mask)
+{
+ struct mem_cgroup *mem;
+ int ret;
+
+ if (mem_cgroup_disabled())
+ return 0;
+
+ ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
+ if (!ret)
+ mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
+
+ return ret;
+}
+
+/*
+ * At replace page cache, newpage is not under any memcg but it's on
+ * LRU. So, this function doesn't touch res_counter but handles LRU
+ * in correct way. Both pages are locked so we cannot race with uncharge.
+ */
+void mem_cgroup_replace_page_cache(struct page *oldpage,
+ struct page *newpage)
+{
+ struct mem_cgroup *memcg;
+ struct page_cgroup *pc;
+ struct zone *zone;
+ enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
+ unsigned long flags;
+
+ if (mem_cgroup_disabled())
+ return;
+
+ pc = lookup_page_cgroup(oldpage);
+ /* fix accounting on old pages */
+ lock_page_cgroup(pc);
+ memcg = pc->mem_cgroup;
+ mem_cgroup_charge_statistics(memcg, PageCgroupCache(pc), -1);
+ ClearPageCgroupUsed(pc);
+ unlock_page_cgroup(pc);
+
+ if (PageSwapBacked(oldpage))
+ type = MEM_CGROUP_CHARGE_TYPE_SHMEM;
+
+ zone = page_zone(newpage);
+ pc = lookup_page_cgroup(newpage);
+ /*
+ * Even if newpage->mapping was NULL before starting replacement,
+ * the newpage may be on LRU(or pagevec for LRU) already. We lock
+ * LRU while we overwrite pc->mem_cgroup.
+ */
+ spin_lock_irqsave(&zone->lru_lock, flags);
+ if (PageLRU(newpage))
+ del_page_from_lru_list(zone, newpage, page_lru(newpage));
+ __mem_cgroup_commit_charge(memcg, newpage, 1, pc, type);
+ if (PageLRU(newpage))
+ add_page_to_lru_list(zone, newpage, page_lru(newpage));
+ spin_unlock_irqrestore(&zone->lru_lock, flags);
+}
+
+#ifdef CONFIG_DEBUG_VM
+static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
+{
+ struct page_cgroup *pc;
+
+ pc = lookup_page_cgroup(page);
+ if (likely(pc) && PageCgroupUsed(pc))
+ return pc;
+ return NULL;
+}
+
+bool mem_cgroup_bad_page_check(struct page *page)
+{
+ if (mem_cgroup_disabled())
+ return false;
+
+ return lookup_page_cgroup_used(page) != NULL;
+}
+
+void mem_cgroup_print_bad_page(struct page *page)
+{
+ struct page_cgroup *pc;
+
+ pc = lookup_page_cgroup_used(page);
+ if (pc) {
+ int ret = -1;
+ char *path;
+
+ printk(KERN_ALERT "pc:%p pc->flags:%lx pc->mem_cgroup:%p",
+ pc, pc->flags, pc->mem_cgroup);
+
+ path = kmalloc(PATH_MAX, GFP_KERNEL);
+ if (path) {
+ rcu_read_lock();
+ ret = cgroup_path(pc->mem_cgroup->css.cgroup,
+ path, PATH_MAX);
+ rcu_read_unlock();
+ }
+
+ printk(KERN_CONT "(%s)\n",
+ (ret < 0) ? "cannot get the path" : path);
+ kfree(path);
+ }
+}
+#endif
+
+static DEFINE_MUTEX(set_limit_mutex);
+
+static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
+ unsigned long long val)
+{
+ int retry_count;
+ u64 memswlimit, memlimit;
+ int ret = 0;
+ int children = mem_cgroup_count_children(memcg);
+ u64 curusage, oldusage;
+ int enlarge;
+
+ /*
+ * 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 * children;
+
+ oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
+
+ enlarge = 0;
+ while (retry_count) {
+ if (signal_pending(current)) {
+ ret = -EINTR;
+ break;
+ }
+ /*
+ * Rather than hide all in some function, I do this in
+ * open coded manner. You see what this really does.
+ * We have to guarantee mem->res.limit < mem->memsw.limit.
+ */
+ mutex_lock(&set_limit_mutex);
+ memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
+ if (memswlimit < val) {
+ ret = -EINVAL;
+ mutex_unlock(&set_limit_mutex);
+ break;
+ }
+
+ memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
+ if (memlimit < val)
+ enlarge = 1;
+
+ ret = res_counter_set_limit(&memcg->res, val);
+ if (!ret) {
+ if (memswlimit == val)
+ memcg->memsw_is_minimum = true;
+ else
+ memcg->memsw_is_minimum = false;
+ }
+ mutex_unlock(&set_limit_mutex);
+
+ if (!ret)
+ break;
+
+ mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
+ MEM_CGROUP_RECLAIM_SHRINK,
+ NULL);
+ curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
+ /* Usage is reduced ? */
+ if (curusage >= oldusage)
+ retry_count--;
+ else
+ oldusage = curusage;
+ }
+ if (!ret && enlarge)
+ memcg_oom_recover(memcg);
+
+ return ret;
+}
+
+static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
+ unsigned long long val)
+{
+ int retry_count;
+ u64 memlimit, memswlimit, oldusage, curusage;
+ int children = mem_cgroup_count_children(memcg);
+ int ret = -EBUSY;
+ int enlarge = 0;
+
+ /* see mem_cgroup_resize_res_limit */
+ retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
+ oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
+ while (retry_count) {
+ if (signal_pending(current)) {
+ ret = -EINTR;
+ break;
+ }
+ /*
+ * Rather than hide all in some function, I do this in
+ * open coded manner. You see what this really does.
+ * We have to guarantee mem->res.limit < mem->memsw.limit.
+ */
+ mutex_lock(&set_limit_mutex);
+ memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
+ if (memlimit > val) {
+ ret = -EINVAL;
+ mutex_unlock(&set_limit_mutex);
+ break;
+ }
+ memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
+ if (memswlimit < val)
+ enlarge = 1;
+ ret = res_counter_set_limit(&memcg->memsw, val);
+ if (!ret) {
+ if (memlimit == val)
+ memcg->memsw_is_minimum = true;
+ else
+ memcg->memsw_is_minimum = false;
+ }
+ mutex_unlock(&set_limit_mutex);
+
+ if (!ret)
+ break;
+
+ mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
+ MEM_CGROUP_RECLAIM_NOSWAP |
+ MEM_CGROUP_RECLAIM_SHRINK,
+ NULL);
+ curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
+ /* Usage is reduced ? */
+ if (curusage >= oldusage)
+ retry_count--;
+ else
+ oldusage = curusage;
+ }
+ 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 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_hierarchical_reclaim(mz->mem, zone,
+ gfp_mask,
+ MEM_CGROUP_RECLAIM_SOFT,
+ &nr_scanned);
+ nr_reclaimed += reclaimed;
+ *total_scanned += nr_scanned;
+ spin_lock(&mctz->lock);
+
+ /*
+ * If we failed to reclaim anything from this memory cgroup
+ * it is time to move on to the next cgroup
+ */
+ next_mz = NULL;
+ if (!reclaimed) {
+ do {
+ /*
+ * Loop until we find yet another one.
+ *
+ * By the time we get the soft_limit lock
+ * again, someone might have aded the
+ * group back on the RB tree. Iterate to
+ * make sure we get a different mem.
+ * mem_cgroup_largest_soft_limit_node returns
+ * NULL if no other cgroup is present on
+ * the tree
+ */
+ next_mz =
+ __mem_cgroup_largest_soft_limit_node(mctz);
+ if (next_mz == mz)
+ css_put(&next_mz->mem->css);
+ else /* next_mz == NULL or other memcg */
+ break;
+ } while (1);
+ }
+ __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
+ excess = res_counter_soft_limit_excess(&mz->mem->res);
+ /*
+ * 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->mem, mz, mctz, excess);
+ spin_unlock(&mctz->lock);
+ css_put(&mz->mem->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->mem->css);
+ return nr_reclaimed;
+}
+
+/*
+ * This routine traverse page_cgroup in given list and drop them all.
+ * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
+ */
+static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
+ int node, int zid, enum lru_list lru)
+{
+ struct zone *zone;
+ struct mem_cgroup_per_zone *mz;
+ struct page_cgroup *pc, *busy;
+ unsigned long flags, loop;
+ struct list_head *list;
+ int ret = 0;
+
+ zone = &NODE_DATA(node)->node_zones[zid];
+ mz = mem_cgroup_zoneinfo(mem, node, zid);
+ list = &mz->lists[lru];
+
+ loop = MEM_CGROUP_ZSTAT(mz, lru);
+ /* give some margin against EBUSY etc...*/
+ loop += 256;
+ busy = NULL;
+ while (loop--) {
+ struct page *page;
+
+ ret = 0;
+ spin_lock_irqsave(&zone->lru_lock, flags);
+ if (list_empty(list)) {
+ spin_unlock_irqrestore(&zone->lru_lock, flags);
+ break;
+ }
+ pc = list_entry(list->prev, struct page_cgroup, lru);
+ if (busy == pc) {
+ list_move(&pc->lru, list);
+ busy = NULL;
+ spin_unlock_irqrestore(&zone->lru_lock, flags);
+ continue;
+ }
+ spin_unlock_irqrestore(&zone->lru_lock, flags);
+
+ page = lookup_cgroup_page(pc);
+
+ ret = mem_cgroup_move_parent(page, pc, mem, GFP_KERNEL);
+ if (ret == -ENOMEM)
+ break;
+
+ if (ret == -EBUSY || ret == -EINVAL) {
+ /* found lock contention or "pc" is obsolete. */
+ busy = pc;
+ cond_resched();
+ } else
+ busy = NULL;
+ }
+
+ if (!ret && !list_empty(list))
+ return -EBUSY;
+ return ret;
+}
+
+/*
+ * make mem_cgroup's charge to be 0 if there is no task.
+ * This enables deleting this mem_cgroup.
+ */
+static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
+{
+ int ret;
+ int node, zid, shrink;
+ int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+ struct cgroup *cgrp = mem->css.cgroup;
+
+ css_get(&mem->css);
+
+ shrink = 0;
+ /* should free all ? */
+ if (free_all)
+ goto try_to_free;
+move_account:
+ do {
+ ret = -EBUSY;
+ if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
+ goto out;
+ ret = -EINTR;
+ if (signal_pending(current))
+ goto out;
+ /* This is for making all *used* pages to be on LRU. */
+ lru_add_drain_all();
+ drain_all_stock_sync();
+ ret = 0;
+ mem_cgroup_start_move(mem);
+ for_each_node_state(node, N_HIGH_MEMORY) {
+ for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
+ enum lru_list l;
+ for_each_lru(l) {
+ ret = mem_cgroup_force_empty_list(mem,
+ node, zid, l);
+ if (ret)
+ break;
+ }
+ }
+ if (ret)
+ break;
+ }
+ mem_cgroup_end_move(mem);
+ memcg_oom_recover(mem);
+ /* it seems parent cgroup doesn't have enough mem */
+ if (ret == -ENOMEM)
+ goto try_to_free;
+ cond_resched();
+ /* "ret" should also be checked to ensure all lists are empty. */
+ } while (mem->res.usage > 0 || ret);
+out:
+ css_put(&mem->css);
+ return ret;
+
+try_to_free:
+ /* returns EBUSY if there is a task or if we come here twice. */
+ if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
+ ret = -EBUSY;
+ goto out;
+ }
+ /* we call try-to-free pages for make this cgroup empty */
+ lru_add_drain_all();
+ /* try to free all pages in this cgroup */
+ shrink = 1;
+ while (nr_retries && mem->res.usage > 0) {
+ int progress;
+
+ if (signal_pending(current)) {
+ ret = -EINTR;
+ goto out;
+ }
+ progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
+ false, get_swappiness(mem));
+ if (!progress) {
+ nr_retries--;
+ /* maybe some writeback is necessary */
+ congestion_wait(BLK_RW_ASYNC, HZ/10);
+ }
+
+ }
+ lru_add_drain();
+ /* try move_account...there may be some *locked* pages. */
+ goto move_account;
+}
+
+int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
+{
+ return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
+}
+
+
+static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
+{
+ return mem_cgroup_from_cont(cont)->use_hierarchy;
+}
+
+static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
+ u64 val)
+{
+ int retval = 0;
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
+ struct cgroup *parent = cont->parent;
+ struct mem_cgroup *parent_mem = NULL;
+
+ if (parent)
+ parent_mem = mem_cgroup_from_cont(parent);
+
+ cgroup_lock();
+ /*
+ * 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_mem || !parent_mem->use_hierarchy) &&
+ (val == 1 || val == 0)) {
+ if (list_empty(&cont->children))
+ mem->use_hierarchy = val;
+ else
+ retval = -EBUSY;
+ } else
+ retval = -EINVAL;
+ cgroup_unlock();
+
+ return retval;
+}
+
+
+static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *mem,
+ 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, mem)
+ val += mem_cgroup_read_stat(iter, idx);
+
+ if (val < 0) /* race ? */
+ val = 0;
+ return val;
+}
+
+static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap)
+{
+ u64 val;
+
+ if (!mem_cgroup_is_root(mem)) {
+ if (!swap)
+ return res_counter_read_u64(&mem->res, RES_USAGE);
+ else
+ return res_counter_read_u64(&mem->memsw, RES_USAGE);
+ }
+
+ val = mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_CACHE);
+ val += mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_RSS);
+
+ if (swap)
+ val += mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
+
+ return val << PAGE_SHIFT;
+}
+
+static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
+{
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
+ u64 val;
+ int type, name;
+
+ type = MEMFILE_TYPE(cft->private);
+ name = MEMFILE_ATTR(cft->private);
+ switch (type) {
+ case _MEM:
+ if (name == RES_USAGE)
+ val = mem_cgroup_usage(mem, false);
+ else
+ val = res_counter_read_u64(&mem->res, name);
+ break;
+ case _MEMSWAP:
+ if (name == RES_USAGE)
+ val = mem_cgroup_usage(mem, true);
+ else
+ val = res_counter_read_u64(&mem->memsw, name);
+ break;
+ default:
+ BUG();
+ break;
+ }
+ return val;
+}
+/*
+ * The user of this function is...
+ * RES_LIMIT.
+ */
+static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
+ const char *buffer)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
+ int type, name;
+ unsigned long long val;
+ int ret;
+
+ type = MEMFILE_TYPE(cft->private);
+ name = MEMFILE_ATTR(cft->private);
+ switch (name) {
+ case RES_LIMIT:
+ if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
+ ret = -EINVAL;
+ break;
+ }
+ /* This function does all necessary parse...reuse it */
+ ret = res_counter_memparse_write_strategy(buffer, &val);
+ if (ret)
+ break;
+ if (type == _MEM)
+ ret = mem_cgroup_resize_limit(memcg, val);
+ else
+ ret = mem_cgroup_resize_memsw_limit(memcg, val);
+ break;
+ case RES_SOFT_LIMIT:
+ ret = res_counter_memparse_write_strategy(buffer, &val);
+ if (ret)
+ break;
+ /*
+ * For memsw, soft limits are hard to implement in terms
+ * of semantics, for now, we support soft limits for
+ * control without swap
+ */
+ if (type == _MEM)
+ ret = res_counter_set_soft_limit(&memcg->res, val);
+ else
+ ret = -EINVAL;
+ break;
+ default:
+ ret = -EINVAL; /* should be BUG() ? */
+ break;
+ }
+ return ret;
+}
+
+static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
+ unsigned long long *mem_limit, unsigned long long *memsw_limit)
+{
+ struct cgroup *cgroup;
+ unsigned long long min_limit, min_memsw_limit, tmp;
+
+ min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
+ min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
+ cgroup = memcg->css.cgroup;
+ if (!memcg->use_hierarchy)
+ goto out;
+
+ while (cgroup->parent) {
+ cgroup = cgroup->parent;
+ memcg = mem_cgroup_from_cont(cgroup);
+ if (!memcg->use_hierarchy)
+ break;
+ tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
+ min_limit = min(min_limit, tmp);
+ tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
+ min_memsw_limit = min(min_memsw_limit, tmp);
+ }
+out:
+ *mem_limit = min_limit;
+ *memsw_limit = min_memsw_limit;
+ return;
+}
+
+static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
+{
+ struct mem_cgroup *mem;
+ int type, name;
+
+ mem = mem_cgroup_from_cont(cont);
+ type = MEMFILE_TYPE(event);
+ name = MEMFILE_ATTR(event);
+ switch (name) {
+ case RES_MAX_USAGE:
+ if (type == _MEM)
+ res_counter_reset_max(&mem->res);
+ else
+ res_counter_reset_max(&mem->memsw);
+ break;
+ case RES_FAILCNT:
+ if (type == _MEM)
+ res_counter_reset_failcnt(&mem->res);
+ else
+ res_counter_reset_failcnt(&mem->memsw);
+ break;
+ }
+
+ return 0;
+}
+
+static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
+ struct cftype *cft)
+{
+ return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
+}
+
+#ifdef CONFIG_MMU
+static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
+ struct cftype *cft, u64 val)
+{
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
+
+ if (val >= (1 << NR_MOVE_TYPE))
+ return -EINVAL;
+ /*
+ * We check this value several times in both in can_attach() and
+ * attach(), so we need cgroup lock to prevent this value from being
+ * inconsistent.
+ */
+ cgroup_lock();
+ mem->move_charge_at_immigrate = val;
+ cgroup_unlock();
+
+ return 0;
+}
+#else
+static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
+ struct cftype *cft, u64 val)
+{
+ return -ENOSYS;
+}
+#endif
+
+
+/* For read statistics */
+enum {
+ MCS_CACHE,
+ MCS_RSS,
+ MCS_FILE_MAPPED,
+ MCS_PGPGIN,
+ MCS_PGPGOUT,
+ MCS_SWAP,
+ MCS_PGFAULT,
+ MCS_PGMAJFAULT,
+ MCS_INACTIVE_ANON,
+ MCS_ACTIVE_ANON,
+ MCS_INACTIVE_FILE,
+ MCS_ACTIVE_FILE,
+ MCS_UNEVICTABLE,
+ NR_MCS_STAT,
+};
+
+struct mcs_total_stat {
+ s64 stat[NR_MCS_STAT];
+};
+
+struct {
+ char *local_name;
+ char *total_name;
+} memcg_stat_strings[NR_MCS_STAT] = {
+ {"cache", "total_cache"},
+ {"rss", "total_rss"},
+ {"mapped_file", "total_mapped_file"},
+ {"pgpgin", "total_pgpgin"},
+ {"pgpgout", "total_pgpgout"},
+ {"swap", "total_swap"},
+ {"pgfault", "total_pgfault"},
+ {"pgmajfault", "total_pgmajfault"},
+ {"inactive_anon", "total_inactive_anon"},
+ {"active_anon", "total_active_anon"},
+ {"inactive_file", "total_inactive_file"},
+ {"active_file", "total_active_file"},
+ {"unevictable", "total_unevictable"}
+};
+
+
+static void
+mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
+{
+ s64 val;
+
+ /* per cpu stat */
+ val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
+ s->stat[MCS_CACHE] += val * PAGE_SIZE;
+ val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
+ s->stat[MCS_RSS] += val * PAGE_SIZE;
+ val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED);
+ s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE;
+ val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGPGIN);
+ s->stat[MCS_PGPGIN] += val;
+ val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGPGOUT);
+ s->stat[MCS_PGPGOUT] += val;
+ if (do_swap_account) {
+ val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
+ s->stat[MCS_SWAP] += val * PAGE_SIZE;
+ }
+ val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGFAULT);
+ s->stat[MCS_PGFAULT] += val;
+ val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGMAJFAULT);
+ s->stat[MCS_PGMAJFAULT] += val;
+
+ /* per zone stat */
+ val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
+ s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
+ val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON);
+ s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE;
+ val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE);
+ s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE;
+ val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE);
+ s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE;
+ val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE);
+ s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE;
+}
+
+static void
+mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
+{
+ struct mem_cgroup *iter;
+
+ for_each_mem_cgroup_tree(iter, mem)
+ mem_cgroup_get_local_stat(iter, s);
+}
+
+#ifdef CONFIG_NUMA
+static int mem_control_numa_stat_show(struct seq_file *m, void *arg)
+{
+ int nid;
+ unsigned long total_nr, file_nr, anon_nr, unevictable_nr;
+ unsigned long node_nr;
+ struct cgroup *cont = m->private;
+ struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
+
+ total_nr = mem_cgroup_nr_lru_pages(mem_cont);
+ seq_printf(m, "total=%lu", total_nr);
+ for_each_node_state(nid, N_HIGH_MEMORY) {
+ node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid);
+ seq_printf(m, " N%d=%lu", nid, node_nr);
+ }
+ seq_putc(m, '\n');
+
+ file_nr = mem_cgroup_nr_file_lru_pages(mem_cont);
+ seq_printf(m, "file=%lu", file_nr);
+ for_each_node_state(nid, N_HIGH_MEMORY) {
+ node_nr = mem_cgroup_node_nr_file_lru_pages(mem_cont, nid);
+ seq_printf(m, " N%d=%lu", nid, node_nr);
+ }
+ seq_putc(m, '\n');
+
+ anon_nr = mem_cgroup_nr_anon_lru_pages(mem_cont);
+ seq_printf(m, "anon=%lu", anon_nr);
+ for_each_node_state(nid, N_HIGH_MEMORY) {
+ node_nr = mem_cgroup_node_nr_anon_lru_pages(mem_cont, nid);
+ seq_printf(m, " N%d=%lu", nid, node_nr);
+ }
+ seq_putc(m, '\n');
+
+ unevictable_nr = mem_cgroup_nr_unevictable_lru_pages(mem_cont);
+ seq_printf(m, "unevictable=%lu", unevictable_nr);
+ for_each_node_state(nid, N_HIGH_MEMORY) {
+ node_nr = mem_cgroup_node_nr_unevictable_lru_pages(mem_cont,
+ nid);
+ seq_printf(m, " N%d=%lu", nid, node_nr);
+ }
+ seq_putc(m, '\n');
+ return 0;
+}
+#endif /* CONFIG_NUMA */
+
+static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
+ struct cgroup_map_cb *cb)
+{
+ struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
+ struct mcs_total_stat mystat;
+ int i;
+
+ memset(&mystat, 0, sizeof(mystat));
+ mem_cgroup_get_local_stat(mem_cont, &mystat);
+
+
+ for (i = 0; i < NR_MCS_STAT; i++) {
+ if (i == MCS_SWAP && !do_swap_account)
+ continue;
+ cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
+ }
+
+ /* Hierarchical information */
+ {
+ unsigned long long limit, memsw_limit;
+ memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
+ cb->fill(cb, "hierarchical_memory_limit", limit);
+ if (do_swap_account)
+ cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
+ }
+
+ memset(&mystat, 0, sizeof(mystat));
+ mem_cgroup_get_total_stat(mem_cont, &mystat);
+ for (i = 0; i < NR_MCS_STAT; i++) {
+ if (i == MCS_SWAP && !do_swap_account)
+ continue;
+ cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
+ }
+
+#ifdef CONFIG_DEBUG_VM
+ cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
+
+ {
+ int nid, zid;
+ struct mem_cgroup_per_zone *mz;
+ 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 = mem_cgroup_zoneinfo(mem_cont, nid, zid);
+
+ recent_rotated[0] +=
+ mz->reclaim_stat.recent_rotated[0];
+ recent_rotated[1] +=
+ mz->reclaim_stat.recent_rotated[1];
+ recent_scanned[0] +=
+ mz->reclaim_stat.recent_scanned[0];
+ recent_scanned[1] +=
+ mz->reclaim_stat.recent_scanned[1];
+ }
+ cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
+ cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
+ cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
+ cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
+ }
+#endif
+
+ return 0;
+}
+
+static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+
+ return get_swappiness(memcg);
+}
+
+static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
+ u64 val)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+ struct mem_cgroup *parent;
+
+ if (val > 100)
+ return -EINVAL;
+
+ if (cgrp->parent == NULL)
+ return -EINVAL;
+
+ parent = mem_cgroup_from_cont(cgrp->parent);
+
+ cgroup_lock();
+
+ /* If under hierarchy, only empty-root can set this value */
+ if ((parent->use_hierarchy) ||
+ (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
+ cgroup_unlock();
+ return -EINVAL;
+ }
+
+ memcg->swappiness = val;
+
+ cgroup_unlock();
+
+ return 0;
+}
+
+static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
+{
+ struct mem_cgroup_threshold_ary *t;
+ u64 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 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;
+
+ return _a->threshold - _b->threshold;
+}
+
+static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem)
+{
+ struct mem_cgroup_eventfd_list *ev;
+
+ list_for_each_entry(ev, &mem->oom_notify, list)
+ eventfd_signal(ev->eventfd, 1);
+ return 0;
+}
+
+static void mem_cgroup_oom_notify(struct mem_cgroup *mem)
+{
+ struct mem_cgroup *iter;
+
+ for_each_mem_cgroup_tree(iter, mem)
+ mem_cgroup_oom_notify_cb(iter);
+}
+
+static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
+ struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+ struct mem_cgroup_thresholds *thresholds;
+ struct mem_cgroup_threshold_ary *new;
+ int type = MEMFILE_TYPE(cft->private);
+ u64 threshold, usage;
+ int i, size, ret;
+
+ ret = res_counter_memparse_write_strategy(args, &threshold);
+ if (ret)
+ return ret;
+
+ mutex_lock(&memcg->thresholds_lock);
+
+ if (type == _MEM)
+ thresholds = &memcg->thresholds;
+ else if (type == _MEMSWAP)
+ thresholds = &memcg->memsw_thresholds;
+ else
+ BUG();
+
+ usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
+
+ /* 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;
+ }
+ }
+
+ /* 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 void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
+ struct cftype *cft, struct eventfd_ctx *eventfd)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+ struct mem_cgroup_thresholds *thresholds;
+ struct mem_cgroup_threshold_ary *new;
+ int type = MEMFILE_TYPE(cft->private);
+ u64 usage;
+ int i, j, size;
+
+ mutex_lock(&memcg->thresholds_lock);
+ if (type == _MEM)
+ thresholds = &memcg->thresholds;
+ else if (type == _MEMSWAP)
+ thresholds = &memcg->memsw_thresholds;
+ else
+ BUG();
+
+ /*
+ * Something went wrong if we trying to unregister a threshold
+ * if we don't have thresholds
+ */
+ BUG_ON(!thresholds);
+
+ if (!thresholds->primary)
+ goto unlock;
+
+ usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
+
+ /* 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 int mem_cgroup_oom_register_event(struct cgroup *cgrp,
+ struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+ struct mem_cgroup_eventfd_list *event;
+ int type = MEMFILE_TYPE(cft->private);
+
+ BUG_ON(type != _OOM_TYPE);
+ event = kmalloc(sizeof(*event), GFP_KERNEL);
+ if (!event)
+ return -ENOMEM;
+
+ mutex_lock(&memcg_oom_mutex);
+
+ event->eventfd = eventfd;
+ list_add(&event->list, &memcg->oom_notify);
+
+ /* already in OOM ? */
+ if (atomic_read(&memcg->oom_lock))
+ eventfd_signal(eventfd, 1);
+ mutex_unlock(&memcg_oom_mutex);
+
+ return 0;
+}
+
+static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
+ struct cftype *cft, struct eventfd_ctx *eventfd)
+{
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
+ struct mem_cgroup_eventfd_list *ev, *tmp;
+ int type = MEMFILE_TYPE(cft->private);
+
+ BUG_ON(type != _OOM_TYPE);
+
+ mutex_lock(&memcg_oom_mutex);
+
+ list_for_each_entry_safe(ev, tmp, &mem->oom_notify, list) {
+ if (ev->eventfd == eventfd) {
+ list_del(&ev->list);
+ kfree(ev);
+ }
+ }
+
+ mutex_unlock(&memcg_oom_mutex);
+}
+
+static int mem_cgroup_oom_control_read(struct cgroup *cgrp,
+ struct cftype *cft, struct cgroup_map_cb *cb)
+{
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
+
+ cb->fill(cb, "oom_kill_disable", mem->oom_kill_disable);
+
+ if (atomic_read(&mem->oom_lock))
+ cb->fill(cb, "under_oom", 1);
+ else
+ cb->fill(cb, "under_oom", 0);
+ return 0;
+}
+
+static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
+ struct cftype *cft, u64 val)
+{
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
+ struct mem_cgroup *parent;
+
+ /* cannot set to root cgroup and only 0 and 1 are allowed */
+ if (!cgrp->parent || !((val == 0) || (val == 1)))
+ return -EINVAL;
+
+ parent = mem_cgroup_from_cont(cgrp->parent);
+
+ cgroup_lock();
+ /* oom-kill-disable is a flag for subhierarchy. */
+ if ((parent->use_hierarchy) ||
+ (mem->use_hierarchy && !list_empty(&cgrp->children))) {
+ cgroup_unlock();
+ return -EINVAL;
+ }
+ mem->oom_kill_disable = val;
+ if (!val)
+ memcg_oom_recover(mem);
+ cgroup_unlock();
+ return 0;
+}
+
+#ifdef CONFIG_NUMA
+static const struct file_operations mem_control_numa_stat_file_operations = {
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+static int mem_control_numa_stat_open(struct inode *unused, struct file *file)
+{
+ struct cgroup *cont = file->f_dentry->d_parent->d_fsdata;
+
+ file->f_op = &mem_control_numa_stat_file_operations;
+ return single_open(file, mem_control_numa_stat_show, cont);
+}
+#endif /* CONFIG_NUMA */
+
+static struct cftype mem_cgroup_files[] = {
+ {
+ .name = "usage_in_bytes",
+ .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
+ .read_u64 = mem_cgroup_read,
+ .register_event = mem_cgroup_usage_register_event,
+ .unregister_event = mem_cgroup_usage_unregister_event,
+ },
+ {
+ .name = "max_usage_in_bytes",
+ .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
+ .trigger = mem_cgroup_reset,
+ .read_u64 = mem_cgroup_read,
+ },
+ {
+ .name = "limit_in_bytes",
+ .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
+ .write_string = mem_cgroup_write,
+ .read_u64 = mem_cgroup_read,
+ },
+ {
+ .name = "soft_limit_in_bytes",
+ .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
+ .write_string = mem_cgroup_write,
+ .read_u64 = mem_cgroup_read,
+ },
+ {
+ .name = "failcnt",
+ .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
+ .trigger = mem_cgroup_reset,
+ .read_u64 = mem_cgroup_read,
+ },
+ {
+ .name = "stat",
+ .read_map = mem_control_stat_show,
+ },
+ {
+ .name = "force_empty",
+ .trigger = mem_cgroup_force_empty_write,
+ },
+ {
+ .name = "use_hierarchy",
+ .write_u64 = mem_cgroup_hierarchy_write,
+ .read_u64 = mem_cgroup_hierarchy_read,
+ },
+ {
+ .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",
+ .read_map = mem_cgroup_oom_control_read,
+ .write_u64 = mem_cgroup_oom_control_write,
+ .register_event = mem_cgroup_oom_register_event,
+ .unregister_event = mem_cgroup_oom_unregister_event,
+ .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
+ },
+#ifdef CONFIG_NUMA
+ {
+ .name = "numa_stat",
+ .open = mem_control_numa_stat_open,
+ .mode = S_IRUGO,
+ },
+#endif
+};
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+static struct cftype memsw_cgroup_files[] = {
+ {
+ .name = "memsw.usage_in_bytes",
+ .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
+ .read_u64 = mem_cgroup_read,
+ .register_event = mem_cgroup_usage_register_event,
+ .unregister_event = mem_cgroup_usage_unregister_event,
+ },
+ {
+ .name = "memsw.max_usage_in_bytes",
+ .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
+ .trigger = mem_cgroup_reset,
+ .read_u64 = mem_cgroup_read,
+ },
+ {
+ .name = "memsw.limit_in_bytes",
+ .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
+ .write_string = mem_cgroup_write,
+ .read_u64 = mem_cgroup_read,
+ },
+ {
+ .name = "memsw.failcnt",
+ .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
+ .trigger = mem_cgroup_reset,
+ .read_u64 = mem_cgroup_read,
+ },
+};
+
+static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
+{
+ if (!do_swap_account)
+ return 0;
+ return cgroup_add_files(cont, ss, memsw_cgroup_files,
+ ARRAY_SIZE(memsw_cgroup_files));
+};
+#else
+static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
+{
+ return 0;
+}
+#endif
+
+static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
+{
+ struct mem_cgroup_per_node *pn;
+ struct mem_cgroup_per_zone *mz;
+ enum lru_list l;
+ 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;
+
+ mem->info.nodeinfo[node] = pn;
+ for (zone = 0; zone < MAX_NR_ZONES; zone++) {
+ mz = &pn->zoneinfo[zone];
+ for_each_lru(l)
+ INIT_LIST_HEAD(&mz->lists[l]);
+ mz->usage_in_excess = 0;
+ mz->on_tree = false;
+ mz->mem = mem;
+ }
+ return 0;
+}
+
+static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
+{
+ kfree(mem->info.nodeinfo[node]);
+}
+
+static struct mem_cgroup *mem_cgroup_alloc(void)
+{
+ struct mem_cgroup *mem;
+ int size = sizeof(struct mem_cgroup);
+
+ /* Can be very big if MAX_NUMNODES is very big */
+ if (size < PAGE_SIZE)
+ mem = kzalloc(size, GFP_KERNEL);
+ else
+ mem = vzalloc(size);
+
+ if (!mem)
+ return NULL;
+
+ mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
+ if (!mem->stat)
+ goto out_free;
+ spin_lock_init(&mem->pcp_counter_lock);
+ return mem;
+
+out_free:
+ if (size < PAGE_SIZE)
+ kfree(mem);
+ else
+ vfree(mem);
+ 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 *mem)
+{
+ int node;
+
+ mem_cgroup_remove_from_trees(mem);
+ free_css_id(&mem_cgroup_subsys, &mem->css);
+
+ for_each_node_state(node, N_POSSIBLE)
+ free_mem_cgroup_per_zone_info(mem, node);
+
+ free_percpu(mem->stat);
+ if (sizeof(struct mem_cgroup) < PAGE_SIZE)
+ kfree(mem);
+ else
+ vfree(mem);
+}
+
+static void mem_cgroup_get(struct mem_cgroup *mem)
+{
+ atomic_inc(&mem->refcnt);
+}
+
+static void __mem_cgroup_put(struct mem_cgroup *mem, int count)
+{
+ if (atomic_sub_and_test(count, &mem->refcnt)) {
+ struct mem_cgroup *parent = parent_mem_cgroup(mem);
+ __mem_cgroup_free(mem);
+ if (parent)
+ mem_cgroup_put(parent);
+ }
+}
+
+static void mem_cgroup_put(struct mem_cgroup *mem)
+{
+ __mem_cgroup_put(mem, 1);
+}
+
+/*
+ * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
+ */
+static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem)
+{
+ if (!mem->res.parent)
+ return NULL;
+ return mem_cgroup_from_res_counter(mem->res.parent, res);
+}
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+static void __init enable_swap_cgroup(void)
+{
+ if (!mem_cgroup_disabled() && really_do_swap_account)
+ do_swap_account = 1;
+}
+#else
+static void __init enable_swap_cgroup(void)
+{
+}
+#endif
+
+static int 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_state(node, N_POSSIBLE) {
+ tmp = node;
+ if (!node_state(node, N_NORMAL_MEMORY))
+ tmp = -1;
+ rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
+ if (!rtpn)
+ return 1;
+
+ 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);
+ }
+ }
+ return 0;
+}
+
+static struct cgroup_subsys_state * __ref
+mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
+{
+ struct mem_cgroup *mem, *parent;
+ long error = -ENOMEM;
+ int node;
+
+ mem = mem_cgroup_alloc();
+ if (!mem)
+ return ERR_PTR(error);
+
+ for_each_node_state(node, N_POSSIBLE)
+ if (alloc_mem_cgroup_per_zone_info(mem, node))
+ goto free_out;
+
+ /* root ? */
+ if (cont->parent == NULL) {
+ int cpu;
+ enable_swap_cgroup();
+ parent = NULL;
+ if (mem_cgroup_soft_limit_tree_init())
+ goto free_out;
+ root_mem_cgroup = mem;
+ for_each_possible_cpu(cpu) {
+ struct memcg_stock_pcp *stock =
+ &per_cpu(memcg_stock, cpu);
+ INIT_WORK(&stock->work, drain_local_stock);
+ }
+ hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
+ } else {
+ parent = mem_cgroup_from_cont(cont->parent);
+ mem->use_hierarchy = parent->use_hierarchy;
+ mem->oom_kill_disable = parent->oom_kill_disable;
+ }
+
+ if (parent && parent->use_hierarchy) {
+ res_counter_init(&mem->res, &parent->res);
+ res_counter_init(&mem->memsw, &parent->memsw);
+ /*
+ * We increment refcnt of the parent to ensure that we can
+ * safely access it on res_counter_charge/uncharge.
+ * This refcnt will be decremented when freeing this
+ * mem_cgroup(see mem_cgroup_put).
+ */
+ mem_cgroup_get(parent);
+ } else {
+ res_counter_init(&mem->res, NULL);
+ res_counter_init(&mem->memsw, NULL);
+ }
+ mem->last_scanned_child = 0;
+ mem->last_scanned_node = MAX_NUMNODES;
+ INIT_LIST_HEAD(&mem->oom_notify);
+
+ if (parent)
+ mem->swappiness = get_swappiness(parent);
+ atomic_set(&mem->refcnt, 1);
+ mem->move_charge_at_immigrate = 0;
+ mutex_init(&mem->thresholds_lock);
+ return &mem->css;
+free_out:
+ __mem_cgroup_free(mem);
+ return ERR_PTR(error);
+}
+
+static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
+ struct cgroup *cont)
+{
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
+
+ return mem_cgroup_force_empty(mem, false);
+}
+
+static void mem_cgroup_destroy(struct cgroup_subsys *ss,
+ struct cgroup *cont)
+{
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
+
+ mem_cgroup_put(mem);
+}
+
+static int mem_cgroup_populate(struct cgroup_subsys *ss,
+ struct cgroup *cont)
+{
+ int ret;
+
+ ret = cgroup_add_files(cont, ss, mem_cgroup_files,
+ ARRAY_SIZE(mem_cgroup_files));
+
+ if (!ret)
+ ret = register_memsw_files(cont, ss);
+ return ret;
+}
+
+#ifdef CONFIG_MMU
+/* Handlers for move charge at task migration. */
+#define PRECHARGE_COUNT_AT_ONCE 256
+static int mem_cgroup_do_precharge(unsigned long count)
+{
+ int ret = 0;
+ int batch_count = PRECHARGE_COUNT_AT_ONCE;
+ struct mem_cgroup *mem = mc.to;
+
+ if (mem_cgroup_is_root(mem)) {
+ mc.precharge += count;
+ /* we don't need css_get for root */
+ return ret;
+ }
+ /* try to charge at once */
+ if (count > 1) {
+ struct res_counter *dummy;
+ /*
+ * "mem" cannot be under rmdir() because we've already checked
+ * by cgroup_lock_live_cgroup() that it is not removed and we
+ * are still under the same cgroup_mutex. So we can postpone
+ * css_get().
+ */
+ if (res_counter_charge(&mem->res, PAGE_SIZE * count, &dummy))
+ goto one_by_one;
+ if (do_swap_account && res_counter_charge(&mem->memsw,
+ PAGE_SIZE * count, &dummy)) {
+ res_counter_uncharge(&mem->res, PAGE_SIZE * count);
+ goto one_by_one;
+ }
+ mc.precharge += count;
+ return ret;
+ }
+one_by_one:
+ /* fall back to one by one charge */
+ while (count--) {
+ if (signal_pending(current)) {
+ ret = -EINTR;
+ break;
+ }
+ if (!batch_count--) {
+ batch_count = PRECHARGE_COUNT_AT_ONCE;
+ cond_resched();
+ }
+ ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, 1, &mem, false);
+ if (ret || !mem)
+ /* mem_cgroup_clear_mc() will do uncharge later */
+ return -ENOMEM;
+ mc.precharge++;
+ }
+ return ret;
+}
+
+/**
+ * is_target_pte_for_mc - check a pte whether it is valid for move 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, /* not used */
+ 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() || page_mapcount(page) > 2)
+ return NULL;
+ } else if (!move_file())
+ /* we ignore mapcount for file pages */
+ return NULL;
+ if (!get_page_unless_zero(page))
+ return NULL;
+
+ return page;
+}
+
+static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
+ unsigned long addr, pte_t ptent, swp_entry_t *entry)
+{
+ int usage_count;
+ struct page *page = NULL;
+ swp_entry_t ent = pte_to_swp_entry(ptent);
+
+ if (!move_anon() || non_swap_entry(ent))
+ return NULL;
+ usage_count = mem_cgroup_count_swap_user(ent, &page);
+ if (usage_count > 1) { /* we don't move shared anon */
+ if (page)
+ put_page(page);
+ return NULL;
+ }
+ if (do_swap_account)
+ entry->val = ent.val;
+
+ return page;
+}
+
+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 inode *inode;
+ struct address_space *mapping;
+ pgoff_t pgoff;
+
+ if (!vma->vm_file) /* anonymous vma */
+ return NULL;
+ if (!move_file())
+ return NULL;
+
+ inode = vma->vm_file->f_path.dentry->d_inode;
+ 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). */
+ if (!mapping_cap_swap_backed(mapping)) { /* normal file */
+ page = find_get_page(mapping, pgoff);
+ } else { /* shmem/tmpfs file. we should take account of swap too. */
+ swp_entry_t ent;
+ mem_cgroup_get_shmem_target(inode, pgoff, &page, &ent);
+ if (do_swap_account)
+ entry->val = ent.val;
+ }
+
+ return page;
+}
+
+static int is_target_pte_for_mc(struct vm_area_struct *vma,
+ unsigned long addr, pte_t ptent, union mc_target *target)
+{
+ struct page *page = NULL;
+ struct page_cgroup *pc;
+ int ret = 0;
+ 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 0;
+ if (page) {
+ pc = lookup_page_cgroup(page);
+ /*
+ * Do only loose check w/o page_cgroup lock.
+ * mem_cgroup_move_account() checks the pc is valid or not under
+ * the lock.
+ */
+ if (PageCgroupUsed(pc) && pc->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 &&
+ css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
+ ret = MC_TARGET_SWAP;
+ if (target)
+ target->ent = ent;
+ }
+ return ret;
+}
+
+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;
+
+ split_huge_page_pmd(walk->mm, pmd);
+ 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 (is_target_pte_for_mc(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) {
+ __mem_cgroup_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) {
+ __mem_cgroup_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))
+ res_counter_uncharge(&mc.from->memsw,
+ PAGE_SIZE * mc.moved_swap);
+ __mem_cgroup_put(mc.from, mc.moved_swap);
+
+ if (!mem_cgroup_is_root(mc.to)) {
+ /*
+ * we charged both to->res and to->memsw, so we should
+ * uncharge to->res.
+ */
+ res_counter_uncharge(&mc.to->res,
+ PAGE_SIZE * mc.moved_swap);
+ }
+ /* we've already done mem_cgroup_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)
+{
+ struct mem_cgroup *from = mc.from;
+
+ /*
+ * 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);
+ mem_cgroup_end_move(from);
+}
+
+static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
+ struct cgroup *cgroup,
+ struct task_struct *p)
+{
+ int ret = 0;
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup);
+
+ if (mem->move_charge_at_immigrate) {
+ struct mm_struct *mm;
+ struct mem_cgroup *from = mem_cgroup_from_task(p);
+
+ VM_BUG_ON(from == mem);
+
+ 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);
+ mem_cgroup_start_move(from);
+ spin_lock(&mc.lock);
+ mc.from = from;
+ mc.to = mem;
+ 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 *ss,
+ struct cgroup *cgroup,
+ struct task_struct *p)
+{
+ 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;
+
+ split_huge_page_pmd(walk->mm, pmd);
+ 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++);
+ union mc_target target;
+ int type;
+ struct page *page;
+ struct page_cgroup *pc;
+ swp_entry_t ent;
+
+ if (!mc.precharge)
+ break;
+
+ type = is_target_pte_for_mc(vma, addr, ptent, &target);
+ switch (type) {
+ case MC_TARGET_PAGE:
+ page = target.page;
+ if (isolate_lru_page(page))
+ goto put;
+ pc = lookup_page_cgroup(page);
+ if (!mem_cgroup_move_account(page, 1, pc,
+ mc.from, mc.to, false)) {
+ mc.precharge--;
+ /* we uncharge from mc.from later. */
+ mc.moved_charge++;
+ }
+ putback_lru_page(page);
+put: /* is_target_pte_for_mc() 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, false)) {
+ 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();
+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);
+}
+
+static void mem_cgroup_move_task(struct cgroup_subsys *ss,
+ struct cgroup *cont,
+ struct cgroup *old_cont,
+ struct task_struct *p)
+{
+ struct mm_struct *mm = get_task_mm(p);
+
+ if (mm) {
+ if (mc.to)
+ mem_cgroup_move_charge(mm);
+ put_swap_token(mm);
+ mmput(mm);
+ }
+ if (mc.to)
+ mem_cgroup_clear_mc();
+}
+#else /* !CONFIG_MMU */
+static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
+ struct cgroup *cgroup,
+ struct task_struct *p)
+{
+ return 0;
+}
+static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
+ struct cgroup *cgroup,
+ struct task_struct *p)
+{
+}
+static void mem_cgroup_move_task(struct cgroup_subsys *ss,
+ struct cgroup *cont,
+ struct cgroup *old_cont,
+ struct task_struct *p)
+{
+}
+#endif
+
+struct cgroup_subsys mem_cgroup_subsys = {
+ .name = "memory",
+ .subsys_id = mem_cgroup_subsys_id,
+ .create = mem_cgroup_create,
+ .pre_destroy = mem_cgroup_pre_destroy,
+ .destroy = mem_cgroup_destroy,
+ .populate = mem_cgroup_populate,
+ .can_attach = mem_cgroup_can_attach,
+ .cancel_attach = mem_cgroup_cancel_attach,
+ .attach = mem_cgroup_move_task,
+ .early_init = 0,
+ .use_id = 1,
+};
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+static int __init enable_swap_account(char *s)
+{
+ /* consider enabled if no parameter or 1 is given */
+ 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);
+
+#endif