* 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
#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/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 "internal.h"
#include <asm/uaccess.h>
struct cgroup_subsys mem_cgroup_subsys __read_mostly;
-static struct kmem_cache *page_cgroup_cache __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;
+static int really_do_swap_account __initdata = 1; /* for remember boot option*/
+#else
+#define do_swap_account (0)
+#endif
+
+/*
+ * Per memcg event counter is incremented at every pagein/pageout. This counter
+ * is used for trigger some periodic events. This is straightforward and better
+ * than using jiffies etc. to handle periodic memcg event.
+ *
+ * These values will be used as !((event) & ((1 <<(thresh)) - 1))
+ */
+#define THRESHOLDS_EVENTS_THRESH (7) /* once in 128 */
+#define SOFTLIMIT_EVENTS_THRESH (10) /* once in 1024 */
/*
* Statistics for memory cgroup.
* 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 rss */
+ MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */
+ MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */
MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */
+ MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
+ MEM_CGROUP_EVENTS, /* incremented at every pagein/pageout */
MEM_CGROUP_STAT_NSTATS,
};
struct mem_cgroup_stat_cpu {
s64 count[MEM_CGROUP_STAT_NSTATS];
-} ____cacheline_aligned_in_smp;
-
-struct mem_cgroup_stat {
- struct mem_cgroup_stat_cpu cpustat[NR_CPUS];
};
/*
- * For accounting under irq disable, no need for increment preempt count.
- */
-static void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat *stat,
- enum mem_cgroup_stat_index idx, int val)
-{
- int cpu = smp_processor_id();
- stat->cpustat[cpu].count[idx] += val;
-}
-
-static s64 mem_cgroup_read_stat(struct mem_cgroup_stat *stat,
- enum mem_cgroup_stat_index idx)
-{
- int cpu;
- s64 ret = 0;
- for_each_possible_cpu(cpu)
- ret += stat->cpustat[cpu].count[idx];
- return ret;
-}
-
-/*
* per-zone information in memory controller.
*/
struct mem_cgroup_per_zone {
/*
* spin_lock to protect the per cgroup LRU
*/
- spinlock_t lru_lock;
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)])
};
/*
+ * 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,
*/
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;
+ /*
+ protect against reclaim related member.
+ */
+ spinlock_t reclaim_param_lock;
+
int prev_priority; /* for recording reclaim priority */
+
/*
- * statistics.
+ * While reclaiming in a hierarchy, we cache the last child we
+ * reclaimed from.
*/
- struct mem_cgroup_stat stat;
+ int last_scanned_child;
+ /*
+ * 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;
};
-static struct mem_cgroup init_mem_cgroup;
+/* Stuffs for move charges at task migration. */
/*
- * We use the lower bit of the page->page_cgroup pointer as a bit spin
- * lock. We need to ensure that page->page_cgroup is at least two
- * byte aligned (based on comments from Nick Piggin). But since
- * bit_spin_lock doesn't actually set that lock bit in a non-debug
- * uniprocessor kernel, we should avoid setting it here too.
+ * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a
+ * left-shifted bitmap of these types.
*/
-#define PAGE_CGROUP_LOCK_BIT 0x0
-#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
-#define PAGE_CGROUP_LOCK (1 << PAGE_CGROUP_LOCK_BIT)
-#else
-#define PAGE_CGROUP_LOCK 0x0
-#endif
+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,
+};
-/*
- * A page_cgroup page is associated with every page descriptor. The
- * page_cgroup helps us identify information about the cgroup
- */
-struct page_cgroup {
- struct list_head lru; /* per cgroup LRU list */
- struct page *page;
- struct mem_cgroup *mem_cgroup;
- int flags;
+/* "mc" and its members are protected by cgroup_mutex */
+static struct move_charge_struct {
+ 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 = {
+ .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
};
-#define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */
-#define PAGE_CGROUP_FLAG_ACTIVE (0x2) /* page is active in this cgroup */
-#define PAGE_CGROUP_FLAG_FILE (0x4) /* page is file system backed */
-static int page_cgroup_nid(struct page_cgroup *pc)
+static bool move_anon(void)
{
- return page_to_nid(pc->page);
+ return test_bit(MOVE_CHARGE_TYPE_ANON,
+ &mc.to->move_charge_at_immigrate);
}
-static enum zone_type page_cgroup_zid(struct page_cgroup *pc)
+static bool move_file(void)
{
- return page_zonenum(pc->page);
+ 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_FORCE, /* used by force_empty */
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,
};
+/* only for here (for easy reading.) */
+#define PCGF_CACHE (1UL << PCG_CACHE)
+#define PCGF_USED (1UL << PCG_USED)
+#define PCGF_LOCK (1UL << PCG_LOCK)
+/* Not used, but added here for completeness */
+#define PCGF_ACCT (1UL << PCG_ACCT)
+
+/* 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)
+
/*
- * Always modified under lru lock. Then, not necessary to preempt_disable()
+ * Reclaim flags for mem_cgroup_hierarchical_reclaim
*/
-static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, int flags,
- bool charge)
-{
- int val = (charge)? 1 : -1;
- struct mem_cgroup_stat *stat = &mem->stat;
-
- VM_BUG_ON(!irqs_disabled());
- if (flags & PAGE_CGROUP_FLAG_CACHE)
- __mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_CACHE, val);
- else
- __mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_RSS, val);
-
- if (charge)
- __mem_cgroup_stat_add_safe(stat,
- MEM_CGROUP_STAT_PGPGIN_COUNT, 1);
- else
- __mem_cgroup_stat_add_safe(stat,
- MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
-}
+#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(void);
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 page_cgroup *pc)
{
int nid = page_cgroup_nid(pc);
int zid = page_cgroup_zid(pc);
+ if (!mem)
+ return NULL;
+
return mem_cgroup_zoneinfo(mem, nid, zid);
}
-static unsigned long mem_cgroup_get_all_zonestat(struct mem_cgroup *mem,
- enum lru_list idx)
+static struct mem_cgroup_tree_per_zone *
+soft_limit_tree_node_zone(int nid, int zid)
{
- int nid, zid;
- struct mem_cgroup_per_zone *mz;
- u64 total = 0;
-
- for_each_online_node(nid)
- for (zid = 0; zid < MAX_NR_ZONES; zid++) {
- mz = mem_cgroup_zoneinfo(mem, nid, zid);
- total += MEM_CGROUP_ZSTAT(mz, idx);
- }
- return total;
+ return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
}
-static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
+static struct mem_cgroup_tree_per_zone *
+soft_limit_tree_from_page(struct page *page)
{
- return container_of(cgroup_subsys_state(cont,
- mem_cgroup_subsys_id), struct mem_cgroup,
- css);
+ 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];
}
-struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
+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)
{
- /*
- * 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;
+ struct rb_node **p = &mctz->rb_root.rb_node;
+ struct rb_node *parent = NULL;
+ struct mem_cgroup_per_zone *mz_node;
- return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
- struct mem_cgroup, css);
+ 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 inline int page_cgroup_locked(struct page *page)
+static void
+__mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
+ struct mem_cgroup_per_zone *mz,
+ struct mem_cgroup_tree_per_zone *mctz)
{
- return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
+ if (!mz->on_tree)
+ return;
+ rb_erase(&mz->tree_node, &mctz->rb_root);
+ mz->on_tree = false;
}
-static void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc)
+static void
+mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
+ struct mem_cgroup_per_zone *mz,
+ struct mem_cgroup_tree_per_zone *mctz)
{
- VM_BUG_ON(!page_cgroup_locked(page));
- page->page_cgroup = ((unsigned long)pc | PAGE_CGROUP_LOCK);
+ spin_lock(&mctz->lock);
+ __mem_cgroup_remove_exceeded(mem, mz, mctz);
+ spin_unlock(&mctz->lock);
}
-struct page_cgroup *page_get_page_cgroup(struct page *page)
+
+static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
{
- return (struct page_cgroup *) (page->page_cgroup & ~PAGE_CGROUP_LOCK);
+ 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 lock_page_cgroup(struct page *page)
+static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem)
{
- bit_spin_lock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
+ 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 int try_lock_page_cgroup(struct page *page)
+static inline unsigned long mem_cgroup_get_excess(struct mem_cgroup *mem)
{
- return bit_spin_trylock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
+ return res_counter_soft_limit_excess(&mem->res) >> PAGE_SHIFT;
}
-static void unlock_page_cgroup(struct page *page)
+static struct mem_cgroup_per_zone *
+__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
{
- bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
+ 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 void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz,
- struct page_cgroup *pc)
+static struct mem_cgroup_per_zone *
+mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
{
- int lru = LRU_BASE;
+ struct mem_cgroup_per_zone *mz;
- if (pc->flags & PAGE_CGROUP_FLAG_ACTIVE)
- lru += LRU_ACTIVE;
- if (pc->flags & PAGE_CGROUP_FLAG_FILE)
- lru += LRU_FILE;
+ spin_lock(&mctz->lock);
+ mz = __mem_cgroup_largest_soft_limit_node(mctz);
+ spin_unlock(&mctz->lock);
+ return mz;
+}
- MEM_CGROUP_ZSTAT(mz, lru) -= 1;
+static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
+ enum mem_cgroup_stat_index idx)
+{
+ int cpu;
+ s64 val = 0;
- mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, false);
- list_del(&pc->lru);
+ for_each_possible_cpu(cpu)
+ val += per_cpu(mem->stat->count[idx], cpu);
+ return val;
}
-static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz,
- struct page_cgroup *pc)
+static s64 mem_cgroup_local_usage(struct mem_cgroup *mem)
{
- int lru = LRU_BASE;
+ s64 ret;
- if (pc->flags & PAGE_CGROUP_FLAG_ACTIVE)
- lru += LRU_ACTIVE;
- if (pc->flags & PAGE_CGROUP_FLAG_FILE)
- lru += LRU_FILE;
-
- MEM_CGROUP_ZSTAT(mz, lru) += 1;
- list_add(&pc->lru, &mz->lists[lru]);
+ ret = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
+ ret += mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
+ return ret;
+}
- mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, true);
+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);
}
-static void __mem_cgroup_move_lists(struct page_cgroup *pc, bool active)
+static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
+ struct page_cgroup *pc,
+ bool charge)
{
- struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
- int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
- int file = pc->flags & PAGE_CGROUP_FLAG_FILE;
- int lru = LRU_FILE * !!file + !!from;
+ int val = (charge) ? 1 : -1;
- MEM_CGROUP_ZSTAT(mz, lru) -= 1;
+ preempt_disable();
- if (active)
- pc->flags |= PAGE_CGROUP_FLAG_ACTIVE;
+ if (PageCgroupCache(pc))
+ __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], val);
else
- pc->flags &= ~PAGE_CGROUP_FLAG_ACTIVE;
+ __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], val);
- lru = LRU_FILE * !!file + !!active;
- MEM_CGROUP_ZSTAT(mz, lru) += 1;
- list_move(&pc->lru, &mz->lists[lru]);
+ if (charge)
+ __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGIN_COUNT]);
+ else
+ __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGOUT_COUNT]);
+ __this_cpu_inc(mem->stat->count[MEM_CGROUP_EVENTS]);
+
+ preempt_enable();
}
-int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
+static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
+ enum lru_list idx)
{
- int ret;
+ int nid, zid;
+ struct mem_cgroup_per_zone *mz;
+ u64 total = 0;
- task_lock(task);
- ret = task->mm && mm_match_cgroup(task->mm, mem);
- task_unlock(task);
- return ret;
+ for_each_online_node(nid)
+ for (zid = 0; zid < MAX_NR_ZONES; zid++) {
+ mz = mem_cgroup_zoneinfo(mem, nid, zid);
+ total += MEM_CGROUP_ZSTAT(mz, idx);
+ }
+ return total;
+}
+
+static bool __memcg_event_check(struct mem_cgroup *mem, int event_mask_shift)
+{
+ s64 val;
+
+ val = this_cpu_read(mem->stat->count[MEM_CGROUP_EVENTS]);
+
+ return !(val & ((1 << event_mask_shift) - 1));
}
/*
- * This routine assumes that the appropriate zone's lru lock is already held
+ * Check events in order.
+ *
*/
-void mem_cgroup_move_lists(struct page *page, bool active)
+static void memcg_check_events(struct mem_cgroup *mem, struct page *page)
{
- struct page_cgroup *pc;
- struct mem_cgroup_per_zone *mz;
- unsigned long flags;
+ /* threshold event is triggered in finer grain than soft limit */
+ if (unlikely(__memcg_event_check(mem, THRESHOLDS_EVENTS_THRESH))) {
+ mem_cgroup_threshold(mem);
+ if (unlikely(__memcg_event_check(mem, SOFTLIMIT_EVENTS_THRESH)))
+ mem_cgroup_update_tree(mem, page);
+ }
+}
- if (mem_cgroup_subsys.disabled)
- return;
+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)
+{
/*
- * We cannot lock_page_cgroup while holding zone's lru_lock,
- * because other holders of lock_page_cgroup can be interrupted
- * with an attempt to rotate_reclaimable_page. But we cannot
- * safely get to page_cgroup without it, so just try_lock it:
- * mem_cgroup_isolate_pages allows for page left on wrong list.
+ * 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 (!try_lock_page_cgroup(page))
- return;
+ if (unlikely(!p))
+ return NULL;
- pc = page_get_page_cgroup(page);
- if (pc) {
- mz = page_cgroup_zoneinfo(pc);
- spin_lock_irqsave(&mz->lru_lock, flags);
- __mem_cgroup_move_lists(pc, active);
- spin_unlock_irqrestore(&mz->lru_lock, flags);
- }
- unlock_page_cgroup(page);
+ return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
+ struct mem_cgroup, css);
}
-/*
- * Calculate mapped_ratio under memory controller. This will be used in
- * vmscan.c for deteremining we have to reclaim mapped pages.
- */
-int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem)
+static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
{
- long total, rss;
+ struct mem_cgroup *mem = NULL;
+ if (!mm)
+ return NULL;
/*
- * usage is recorded in bytes. But, here, we assume the number of
- * physical pages can be represented by "long" on any arch.
+ * 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).
*/
- total = (long) (mem->res.usage >> PAGE_SHIFT) + 1L;
- rss = (long)mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS);
- return (int)((rss * 100L) / total);
+ 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;
}
/*
- * prev_priority control...this will be used in memory reclaim path.
+ * Call callback function against all cgroup under hierarchy tree.
*/
-int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
+static int mem_cgroup_walk_tree(struct mem_cgroup *root, void *data,
+ int (*func)(struct mem_cgroup *, void *))
{
- return mem->prev_priority;
-}
+ int found, ret, nextid;
+ struct cgroup_subsys_state *css;
+ struct mem_cgroup *mem;
-void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority)
-{
- if (priority < mem->prev_priority)
- mem->prev_priority = priority;
+ if (!root->use_hierarchy)
+ return (*func)(root, data);
+
+ nextid = 1;
+ do {
+ ret = 0;
+ mem = NULL;
+
+ rcu_read_lock();
+ css = css_get_next(&mem_cgroup_subsys, nextid, &root->css,
+ &found);
+ if (css && css_tryget(css))
+ mem = container_of(css, struct mem_cgroup, css);
+ rcu_read_unlock();
+
+ if (mem) {
+ ret = (*func)(mem, data);
+ css_put(&mem->css);
+ }
+ nextid = found + 1;
+ } while (!ret && css);
+
+ return ret;
}
-void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority)
+static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
{
- mem->prev_priority = priority;
+ return (mem == root_mem_cgroup);
}
/*
- * Calculate # of pages to be scanned in this priority/zone.
- * See also vmscan.c
+ * 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.
*
- * priority starts from "DEF_PRIORITY" and decremented in each loop.
- * (see include/linux/mmzone.h)
+ * 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.
*/
-long mem_cgroup_calc_reclaim(struct mem_cgroup *mem, struct zone *zone,
- int priority, enum lru_list lru)
+void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
{
- long nr_pages;
- int nid = zone->zone_pgdat->node_id;
- int zid = zone_idx(zone);
- struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid);
+ struct page_cgroup *pc;
+ struct mem_cgroup_per_zone *mz;
- nr_pages = MEM_CGROUP_ZSTAT(mz, lru);
+ 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_ZSTAT(mz, lru) -= 1;
+ if (mem_cgroup_is_root(pc->mem_cgroup))
+ return;
+ VM_BUG_ON(list_empty(&pc->lru));
+ list_del_init(&pc->lru);
+ return;
+}
- return (nr_pages >> priority);
+void mem_cgroup_del_lru(struct page *page)
+{
+ mem_cgroup_del_lru_list(page, page_lru(page));
}
-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)
+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);
+ /*
+ * Used bit is set without atomic ops but after smp_wmb().
+ * For making pc->mem_cgroup visible, insert smp_rmb() here.
+ */
+ smp_rmb();
+ /* unused or root page is not rotated. */
+ if (!PageCgroupUsed(pc) || mem_cgroup_is_root(pc->mem_cgroup))
+ return;
+ mz = page_cgroup_zoneinfo(pc);
+ 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));
+ /*
+ * Used bit is set without atomic ops but after smp_wmb().
+ * For making pc->mem_cgroup visible, insert smp_rmb() here.
+ */
+ smp_rmb();
+ if (!PageCgroupUsed(pc))
+ return;
+
+ mz = page_cgroup_zoneinfo(pc);
+ MEM_CGROUP_ZSTAT(mz, lru) += 1;
+ SetPageCgroupAcctLRU(pc);
+ if (mem_cgroup_is_root(pc->mem_cgroup))
+ return;
+ list_add(&pc->lru, &mz->lists[lru]);
+}
+
+/*
+ * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to
+ * lru because the page may.be reused after it's fully uncharged (because of
+ * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge
+ * it again. This function is only used to charge SwapCache. It's done under
+ * lock_page and expected that zone->lru_lock is never held.
+ */
+static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page)
+{
+ unsigned long flags;
+ struct zone *zone = page_zone(page);
+ struct page_cgroup *pc = lookup_page_cgroup(page);
+
+ 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_swapcache(struct page *page)
+{
+ unsigned long flags;
+ struct zone *zone = page_zone(page);
+ struct page_cgroup *pc = lookup_page_cgroup(page);
+
+ 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;
+
+ task_lock(task);
+ rcu_read_lock();
+ curr = try_get_mem_cgroup_from_mm(task->mm);
+ rcu_read_unlock();
+ task_unlock(task);
+ 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;
+}
+
+/*
+ * prev_priority control...this will be used in memory reclaim path.
+ */
+int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
+{
+ int prev_priority;
+
+ spin_lock(&mem->reclaim_param_lock);
+ prev_priority = mem->prev_priority;
+ spin_unlock(&mem->reclaim_param_lock);
+
+ return prev_priority;
+}
+
+void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority)
+{
+ spin_lock(&mem->reclaim_param_lock);
+ if (priority < mem->prev_priority)
+ mem->prev_priority = priority;
+ spin_unlock(&mem->reclaim_param_lock);
+}
+
+void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority)
+{
+ spin_lock(&mem->reclaim_param_lock);
+ mem->prev_priority = priority;
+ spin_unlock(&mem->reclaim_param_lock);
+}
+
+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_pages(struct mem_cgroup *memcg,
+ struct zone *zone,
+ enum lru_list lru)
+{
+ int nid = zone->zone_pgdat->node_id;
+ int zid = zone_idx(zone);
+ struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
+
+ return MEM_CGROUP_ZSTAT(mz, lru);
+}
+
+struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
+ struct zone *zone)
+{
+ int nid = zone->zone_pgdat->node_id;
+ 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);
+ /*
+ * Used bit is set without atomic ops but after smp_wmb().
+ * For making pc->mem_cgroup visible, insert smp_rmb() here.
+ */
+ smp_rmb();
+ if (!PageCgroupUsed(pc))
+ return NULL;
+
+ mz = page_cgroup_zoneinfo(pc);
+ if (!mz)
+ return NULL;
+
+ 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;
int nid = z->zone_pgdat->node_id;
int zid = zone_idx(z);
struct mem_cgroup_per_zone *mz;
- int lru = LRU_FILE * !!file + !!active;
+ int lru = LRU_FILE * file + active;
+ int ret;
BUG_ON(!mem_cont);
mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
src = &mz->lists[lru];
- spin_lock(&mz->lru_lock);
scan = 0;
list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
if (scan >= nr_to_scan)
break;
- page = pc->page;
-
- if (unlikely(!PageLRU(page)))
- continue;
- /*
- * TODO: play better with lumpy reclaim, grabbing anything.
- */
- if (PageActive(page) && !active) {
- __mem_cgroup_move_lists(pc, true);
+ page = pc->page;
+ if (unlikely(!PageCgroupUsed(pc)))
continue;
- }
- if (!PageActive(page) && active) {
- __mem_cgroup_move_lists(pc, false);
+ if (unlikely(!PageLRU(page)))
continue;
- }
scan++;
- list_move(&pc->lru, &pc_list);
-
- if (__isolate_lru_page(page, mode, file) == 0) {
+ ret = __isolate_lru_page(page, mode, file);
+ switch (ret) {
+ case 0:
list_move(&page->lru, dst);
+ mem_cgroup_del_lru(page);
nr_taken++;
+ 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;
}
}
- list_splice(&pc_list, src);
- spin_unlock(&mz->lru_lock);
-
*scanned = scan;
return nr_taken;
}
-/*
- * 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 *memcg)
+#define mem_cgroup_from_res_counter(counter, member) \
+ container_of(counter, struct mem_cgroup, member)
+
+static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
{
- struct mem_cgroup *mem;
- struct page_cgroup *pc;
- unsigned long flags;
- unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
- struct mem_cgroup_per_zone *mz;
+ if (do_swap_account) {
+ if (res_counter_check_under_limit(&mem->res) &&
+ res_counter_check_under_limit(&mem->memsw))
+ return true;
+ } else
+ if (res_counter_check_under_limit(&mem->res))
+ return true;
+ return false;
+}
+
+static unsigned int get_swappiness(struct mem_cgroup *memcg)
+{
+ struct cgroup *cgrp = memcg->css.cgroup;
+ unsigned int swappiness;
+
+ /* root ? */
+ if (cgrp->parent == NULL)
+ return vm_swappiness;
- pc = kmem_cache_alloc(page_cgroup_cache, gfp_mask);
- if (unlikely(pc == NULL))
- goto err;
+ spin_lock(&memcg->reclaim_param_lock);
+ swappiness = memcg->swappiness;
+ spin_unlock(&memcg->reclaim_param_lock);
+
+ return swappiness;
+}
+
+static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data)
+{
+ int *val = data;
+ (*val)++;
+ return 0;
+}
+/**
+ * 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;
/*
- * 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).
+ * 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.
*/
- if (likely(!memcg)) {
- rcu_read_lock();
- mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
- if (unlikely(!mem)) {
- rcu_read_unlock();
- kmem_cache_free(page_cgroup_cache, pc);
- return 0;
- }
- /*
- * For every charge from the cgroup, increment reference count
- */
- css_get(&mem->css);
- rcu_read_unlock();
- } else {
- mem = memcg;
- css_get(&memcg->css);
- }
+ static char memcg_name[PATH_MAX];
+ int ret;
- while (res_counter_charge(&mem->res, PAGE_SIZE)) {
- if (!(gfp_mask & __GFP_WAIT))
- goto out;
+ if (!memcg || !p)
+ return;
- if (try_to_free_mem_cgroup_pages(mem, gfp_mask))
- continue;
+ 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) {
/*
- * try_to_free_mem_cgroup_pages() might not give us a full
- * picture of reclaim. Some pages are reclaimed and might be
- * moved to swap cache or just unmapped from the cgroup.
- * Check the limit again to see if the reclaim reduced the
- * current usage of the cgroup before giving up
+ * Unfortunately, we are unable to convert to a useful name
+ * But we'll still print out the usage information
*/
- if (res_counter_check_under_limit(&mem->res))
- continue;
+ rcu_read_unlock();
+ goto done;
+ }
+ rcu_read_unlock();
- if (!nr_retries--) {
- mem_cgroup_out_of_memory(mem, gfp_mask);
- goto out;
- }
+ 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();
- pc->mem_cgroup = mem;
- pc->page = page;
/*
- * If a page is accounted as a page cache, insert to inactive list.
- * If anon, insert to active list.
+ * Continues from above, so we don't need an KERN_ level
*/
- if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE) {
- pc->flags = PAGE_CGROUP_FLAG_CACHE;
- if (page_is_file_cache(page))
- pc->flags |= PAGE_CGROUP_FLAG_FILE;
- else
- pc->flags |= PAGE_CGROUP_FLAG_ACTIVE;
- } else if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
- pc->flags = PAGE_CGROUP_FLAG_ACTIVE;
- else /* MEM_CGROUP_CHARGE_TYPE_SHMEM */
- pc->flags = PAGE_CGROUP_FLAG_CACHE | PAGE_CGROUP_FLAG_ACTIVE;
-
- lock_page_cgroup(page);
- if (unlikely(page_get_page_cgroup(page))) {
- unlock_page_cgroup(page);
- res_counter_uncharge(&mem->res, PAGE_SIZE);
- css_put(&mem->css);
- kmem_cache_free(page_cgroup_cache, pc);
- goto done;
- }
- page_assign_page_cgroup(page, pc);
+ printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
+done:
- mz = page_cgroup_zoneinfo(pc);
- spin_lock_irqsave(&mz->lru_lock, flags);
- __mem_cgroup_add_list(mz, pc);
- spin_unlock_irqrestore(&mz->lru_lock, flags);
+ 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));
+}
- unlock_page_cgroup(page);
-done:
- return 0;
-out:
- css_put(&mem->css);
- kmem_cache_free(page_cgroup_cache, pc);
-err:
- return -ENOMEM;
+/*
+ * 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;
+ mem_cgroup_walk_tree(mem, &num, mem_cgroup_count_children_cb);
+ return num;
}
-int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask)
+/*
+ * 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)
{
- if (mem_cgroup_subsys.disabled)
- return 0;
+ struct mem_cgroup *ret = NULL;
+ struct cgroup_subsys_state *css;
+ int nextid, found;
- /*
- * 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, NULL);
+ 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 */
+ spin_lock(&root_mem->reclaim_param_lock);
+ if (!css) {
+ /* this means start scan from ID:1 */
+ root_mem->last_scanned_child = 0;
+ } else
+ root_mem->last_scanned_child = found;
+ spin_unlock(&root_mem->reclaim_param_lock);
+ }
+
+ return ret;
+}
+
+/*
+ * 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)
+{
+ 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 = mem_cgroup_get_excess(root_mem);
+
+ /* If memsw_is_minimum==1, swap-out is of-no-use. */
+ if (root_mem->memsw_is_minimum)
+ noswap = true;
+
+ while (1) {
+ victim = mem_cgroup_select_victim(root_mem);
+ if (victim == root_mem) {
+ loop++;
+ if (loop >= 1)
+ drain_all_stock_async();
+ 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 targetted 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_local_usage(victim)) {
+ /* 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,
+ zone->zone_pgdat->node_id);
+ 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_check_under_soft_limit(&root_mem->res))
+ return total;
+ } else if (mem_cgroup_check_under_limit(root_mem))
+ return 1 + total;
+ }
+ return total;
+}
+
+static int mem_cgroup_oom_lock_cb(struct mem_cgroup *mem, void *data)
+{
+ int *val = (int *)data;
+ int x;
+ /*
+ * Logically, we can stop scanning immediately when we find
+ * a memcg is already locked. But condidering unlock ops and
+ * creation/removal of memcg, scan-all is simple operation.
+ */
+ x = atomic_inc_return(&mem->oom_lock);
+ *val = max(x, *val);
+ return 0;
+}
+/*
+ * 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 lock_count = 0;
+
+ mem_cgroup_walk_tree(mem, &lock_count, mem_cgroup_oom_lock_cb);
+
+ if (lock_count == 1)
+ return true;
+ return false;
+}
+
+static int mem_cgroup_oom_unlock_cb(struct mem_cgroup *mem, void *data)
+{
+ /*
+ * 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.
+ */
+ atomic_add_unless(&mem->oom_lock, -1, 0);
+ return 0;
+}
+
+static void mem_cgroup_oom_unlock(struct mem_cgroup *mem)
+{
+ mem_cgroup_walk_tree(mem, NULL, mem_cgroup_oom_unlock_cb);
+}
+
+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->oom_kill_disable && 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.
+ */
+void mem_cgroup_update_file_mapped(struct page *page, int val)
+{
+ struct mem_cgroup *mem;
+ struct page_cgroup *pc;
+
+ pc = lookup_page_cgroup(page);
+ if (unlikely(!pc))
+ return;
+
+ lock_page_cgroup(pc);
+ mem = pc->mem_cgroup;
+ if (!mem || !PageCgroupUsed(pc))
+ goto done;
+
+ /*
+ * Preemption is already disabled. We can use __this_cpu_xxx
+ */
+ if (val > 0) {
+ __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
+ SetPageCgroupFileMapped(pc);
+ } else {
+ __this_cpu_dec(mem->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
+ ClearPageCgroupFileMapped(pc);
+ }
+
+done:
+ unlock_page_cgroup(pc);
+}
+
+/*
+ * 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_SIZE (32 * PAGE_SIZE)
+struct memcg_stock_pcp {
+ struct mem_cgroup *cached; /* this never be root cgroup */
+ int charge;
+ struct work_struct work;
+};
+static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
+static atomic_t memcg_drain_count;
+
+/*
+ * Try to consume stocked charge on this cpu. If success, PAGE_SIZE 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->charge)
+ stock->charge -= PAGE_SIZE;
+ 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->charge) {
+ res_counter_uncharge(&old->res, stock->charge);
+ if (do_swap_account)
+ res_counter_uncharge(&old->memsw, stock->charge);
+ }
+ stock->cached = NULL;
+ stock->charge = 0;
+}
+
+/*
+ * 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);
+}
+
+/*
+ * 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, int val)
+{
+ struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
+
+ if (stock->cached != mem) { /* reset if necessary */
+ drain_stock(stock);
+ stock->cached = mem;
+ }
+ stock->charge += val;
+ 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(void)
+{
+ int cpu;
+ /* This function is for scheduling "drain" in asynchronous way.
+ * The result of "drain" is not directly handled by callers. Then,
+ * if someone is calling drain, we don't have to call drain more.
+ * Anyway, WORK_STRUCT_PENDING check in queue_work_on() will catch if
+ * there is a race. We just do loose check here.
+ */
+ if (atomic_read(&memcg_drain_count))
+ return;
+ /* Notify other cpus that system-wide "drain" is running */
+ atomic_inc(&memcg_drain_count);
+ get_online_cpus();
+ for_each_online_cpu(cpu) {
+ struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
+ schedule_work_on(cpu, &stock->work);
+ }
+ put_online_cpus();
+ atomic_dec(&memcg_drain_count);
+ /* 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 */
+ atomic_inc(&memcg_drain_count);
+ schedule_on_each_cpu(drain_local_stock);
+ atomic_dec(&memcg_drain_count);
+}
+
+static int __cpuinit memcg_stock_cpu_callback(struct notifier_block *nb,
+ unsigned long action,
+ void *hcpu)
+{
+ int cpu = (unsigned long)hcpu;
+ struct memcg_stock_pcp *stock;
+
+ if (action != CPU_DEAD)
+ return NOTIFY_OK;
+ stock = &per_cpu(memcg_stock, cpu);
+ drain_stock(stock);
+ return NOTIFY_OK;
+}
+
+/*
+ * 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, struct mem_cgroup **memcg, bool oom)
+{
+ struct mem_cgroup *mem, *mem_over_limit;
+ int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+ struct res_counter *fail_res;
+ int csize = CHARGE_SIZE;
+
+ /*
+ * 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).
+ */
+ mem = *memcg;
+ if (likely(!mem)) {
+ mem = try_get_mem_cgroup_from_mm(mm);
+ *memcg = mem;
+ } else {
+ css_get(&mem->css);
+ }
+ if (unlikely(!mem))
+ return 0;
+
+ VM_BUG_ON(css_is_removed(&mem->css));
+ if (mem_cgroup_is_root(mem))
+ goto done;
+
+ while (1) {
+ int ret = 0;
+ unsigned long flags = 0;
+
+ if (consume_stock(mem))
+ goto done;
+
+ ret = res_counter_charge(&mem->res, csize, &fail_res);
+ if (likely(!ret)) {
+ if (!do_swap_account)
+ break;
+ ret = res_counter_charge(&mem->memsw, csize, &fail_res);
+ if (likely(!ret))
+ break;
+ /* mem+swap counter fails */
+ res_counter_uncharge(&mem->res, csize);
+ flags |= MEM_CGROUP_RECLAIM_NOSWAP;
+ mem_over_limit = mem_cgroup_from_res_counter(fail_res,
+ memsw);
+ } else
+ /* mem counter fails */
+ mem_over_limit = mem_cgroup_from_res_counter(fail_res,
+ res);
+
+ /* reduce request size and retry */
+ if (csize > PAGE_SIZE) {
+ csize = PAGE_SIZE;
+ continue;
+ }
+ if (!(gfp_mask & __GFP_WAIT))
+ goto nomem;
+
+ ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
+ gfp_mask, flags);
+ if (ret)
+ continue;
+
+ /*
+ * try_to_free_mem_cgroup_pages() might not give us a full
+ * picture of reclaim. Some pages are reclaimed and might be
+ * moved to swap cache or just unmapped from the cgroup.
+ * Check the limit again to see if the reclaim reduced the
+ * current usage of the cgroup before giving up
+ *
+ */
+ if (mem_cgroup_check_under_limit(mem_over_limit))
+ continue;
+
+ /* try to avoid oom while someone is moving charge */
+ if (mc.moving_task && current != mc.moving_task) {
+ struct mem_cgroup *from, *to;
+ bool do_continue = false;
+ /*
+ * There is a small race that "from" or "to" can be
+ * freed by rmdir, so we use css_tryget().
+ */
+ from = mc.from;
+ to = mc.to;
+ if (from && css_tryget(&from->css)) {
+ if (mem_over_limit->use_hierarchy)
+ do_continue = css_is_ancestor(
+ &from->css,
+ &mem_over_limit->css);
+ else
+ do_continue = (from == mem_over_limit);
+ css_put(&from->css);
+ }
+ if (!do_continue && to && css_tryget(&to->css)) {
+ if (mem_over_limit->use_hierarchy)
+ do_continue = css_is_ancestor(
+ &to->css,
+ &mem_over_limit->css);
+ else
+ do_continue = (to == mem_over_limit);
+ css_put(&to->css);
+ }
+ if (do_continue) {
+ 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);
+ continue;
+ }
+ }
+
+ if (!nr_retries--) {
+ if (!oom)
+ goto nomem;
+ if (mem_cgroup_handle_oom(mem_over_limit, gfp_mask)) {
+ nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+ continue;
+ }
+ /* When we reach here, current task is dying .*/
+ css_put(&mem->css);
+ goto bypass;
+ }
+ }
+ if (csize > PAGE_SIZE)
+ refill_stock(mem, csize - PAGE_SIZE);
+done:
+ return 0;
+nomem:
+ css_put(&mem->css);
+ 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 long count)
+{
+ if (!mem_cgroup_is_root(mem)) {
+ res_counter_uncharge(&mem->res, PAGE_SIZE * count);
+ if (do_swap_account)
+ res_counter_uncharge(&mem->memsw, PAGE_SIZE * count);
+ VM_BUG_ON(test_bit(CSS_ROOT, &mem->css.flags));
+ WARN_ON_ONCE(count > INT_MAX);
+ __css_put(&mem->css, (int)count);
+ }
+ /* we don't need css_put for root */
+}
+
+static void mem_cgroup_cancel_charge(struct mem_cgroup *mem)
+{
+ __mem_cgroup_cancel_charge(mem, 1);
+}
+
+/*
+ * 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;
+}
+
+/*
+ * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be
+ * USED state. If already USED, uncharge and return.
+ */
+
+static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
+ struct page_cgroup *pc,
+ enum charge_type ctype)
+{
+ /* try_charge() can return NULL to *memcg, taking care of it. */
+ if (!mem)
+ return;
+
+ lock_page_cgroup(pc);
+ if (unlikely(PageCgroupUsed(pc))) {
+ unlock_page_cgroup(pc);
+ mem_cgroup_cancel_charge(mem);
+ return;
+ }
+
+ 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, pc, true);
+
+ 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, pc->page);
+}
+
+/**
+ * __mem_cgroup_move_account - move account of the page
+ * @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.)
+ * - the pc is locked, used, and ->mem_cgroup points to @from.
+ *
+ * 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 usefull). 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 void __mem_cgroup_move_account(struct page_cgroup *pc,
+ struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge)
+{
+ VM_BUG_ON(from == to);
+ VM_BUG_ON(PageLRU(pc->page));
+ VM_BUG_ON(!PageCgroupLocked(pc));
+ VM_BUG_ON(!PageCgroupUsed(pc));
+ VM_BUG_ON(pc->mem_cgroup != from);
+
+ 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, pc, false);
+ if (uncharge)
+ /* This is not "cancel", but cancel_charge does all we need. */
+ mem_cgroup_cancel_charge(from);
+
+ /* caller should have done css_get */
+ pc->mem_cgroup = to;
+ mem_cgroup_charge_statistics(to, pc, true);
+ /*
+ * 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
+ * garanteed that "to" is never removed. So, we don't check rmdir
+ * status here.
+ */
+}
+
+/*
+ * check whether the @pc is valid for moving account and call
+ * __mem_cgroup_move_account()
+ */
+static int mem_cgroup_move_account(struct page_cgroup *pc,
+ struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge)
+{
+ int ret = -EINVAL;
+ lock_page_cgroup(pc);
+ if (PageCgroupUsed(pc) && pc->mem_cgroup == from) {
+ __mem_cgroup_move_account(pc, from, to, uncharge);
+ ret = 0;
+ }
+ unlock_page_cgroup(pc);
+ /*
+ * check events
+ */
+ memcg_check_events(to, pc->page);
+ memcg_check_events(from, pc->page);
+ return ret;
+}
+
+/*
+ * move charges to its parent.
+ */
+
+static int mem_cgroup_move_parent(struct page_cgroup *pc,
+ struct mem_cgroup *child,
+ gfp_t gfp_mask)
+{
+ struct page *page = pc->page;
+ struct cgroup *cg = child->css.cgroup;
+ struct cgroup *pcg = cg->parent;
+ struct mem_cgroup *parent;
+ 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;
+
+ parent = mem_cgroup_from_cont(pcg);
+ ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false);
+ if (ret || !parent)
+ goto put_back;
+
+ ret = mem_cgroup_move_account(pc, child, parent, true);
+ if (ret)
+ mem_cgroup_cancel_charge(parent);
+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 *memcg)
+{
+ struct mem_cgroup *mem;
+ struct page_cgroup *pc;
+ int ret;
+
+ pc = lookup_page_cgroup(page);
+ /* can happen at boot */
+ if (unlikely(!pc))
+ return 0;
+ prefetchw(pc);
+
+ mem = memcg;
+ ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
+ if (ret || !mem)
+ return ret;
+
+ __mem_cgroup_commit_charge(mem, 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 (PageCompound(page))
+ 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, NULL);
+}
+
+static void
+__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
+ enum charge_type ctype);
+
+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 && !mem))
+ mm = &init_mm;
+
+ if (page_is_file_cache(page))
+ return mem_cgroup_charge_common(page, mm, gfp_mask,
+ MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
+
+ /* 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, mem);
+
+ 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;
+
+ 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, ptr, true);
+ /* drop extra refcnt from tryget */
+ css_put(&mem->css);
+ return ret;
+charge_cur_mm:
+ if (unlikely(!mm))
+ mm = &init_mm;
+ return __mem_cgroup_try_charge(mm, mask, ptr, true);
+}
+
+static void
+__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
+ enum charge_type ctype)
+{
+ struct page_cgroup *pc;
+
+ if (mem_cgroup_disabled())
+ return;
+ if (!ptr)
+ return;
+ cgroup_exclude_rmdir(&ptr->css);
+ pc = lookup_page_cgroup(page);
+ mem_cgroup_lru_del_before_commit_swapcache(page);
+ __mem_cgroup_commit_charge(ptr, pc, ctype);
+ mem_cgroup_lru_add_after_commit_swapcache(page);
+ /*
+ * 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);
+}
+
+static void
+__do_uncharge(struct mem_cgroup *mem, 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 = ¤t->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 continously 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;
+
+ /*
+ * 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->bytes += PAGE_SIZE;
+ if (uncharge_memsw)
+ batch->memsw_bytes += PAGE_SIZE;
+ return;
+direct_uncharge:
+ res_counter_uncharge(&mem->res, PAGE_SIZE);
+ if (uncharge_memsw)
+ res_counter_uncharge(&mem->memsw, 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 page_cgroup *pc;
+ struct mem_cgroup *mem = NULL;
+ struct mem_cgroup_per_zone *mz;
+
+ if (mem_cgroup_disabled())
+ return NULL;
+
+ if (PageSwapCache(page))
+ return NULL;
+
+ /*
+ * 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;
+ }
+
+ if (!mem_cgroup_is_root(mem))
+ __do_uncharge(mem, ctype);
+ if (ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
+ mem_cgroup_swap_statistics(mem, true);
+ mem_cgroup_charge_statistics(mem, pc, false);
+
+ 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.
+ */
+
+ mz = page_cgroup_zoneinfo(pc);
+ unlock_page_cgroup(pc);
+
+ memcg_check_events(mem, page);
+ /* at swapout, this memcg will be accessed to record to swap */
+ if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
+ css_put(&mem->css);
+
+ 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.bytes = 0;
+ current->memcg_batch.memsw_bytes = 0;
+ }
+}
+
+void mem_cgroup_uncharge_end(void)
+{
+ struct memcg_batch_info *batch = ¤t->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->bytes)
+ res_counter_uncharge(&batch->memcg->res, batch->bytes);
+ if (batch->memsw_bytes)
+ res_counter_uncharge(&batch->memcg->memsw, batch->memsw_bytes);
+ 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 (do_swap_account && swapout && memcg) {
+ swap_cgroup_record(ent, css_id(&memcg->css));
+ mem_cgroup_get(memcg);
+ }
+ if (swapout && memcg)
+ css_put(&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);
+ css_put(&to->css);
+ }
+ return 0;
+ }
+ return -EINVAL;
+}
+#else
+static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
+ struct mem_cgroup *from, struct mem_cgroup *to, 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)
+{
+ struct page_cgroup *pc;
+ struct mem_cgroup *mem = NULL;
+ enum charge_type ctype;
+ int ret = 0;
+
+ 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_KERNEL, 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, 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)
+{
+ struct page *used, *unused;
+ struct page_cgroup *pc;
+
+ if (!mem)
+ return;
+ /* blocks rmdir() */
+ cgroup_exclude_rmdir(&mem->css);
+ /* at migration success, oldpage->mapping is NULL. */
+ if (oldpage->mapping) {
+ 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);
+
+ if (unused != oldpage)
+ pc = lookup_page_cgroup(unused);
+ __mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);
+
+ pc = lookup_page_cgroup(used);
+ /*
+ * 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 = NULL;
+ 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;
+}
+
+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);
+ 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);
+ 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, int nid,
+ int zid)
+{
+ 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;
+
+ if (order > 0)
+ return 0;
+
+ mctz = soft_limit_tree_node_zone(nid, zid);
+ /*
+ * 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;
+
+ reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone,
+ gfp_mask,
+ MEM_CGROUP_RECLAIM_SOFT);
+ nr_reclaimed += reclaimed;
+ 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);
+ next_mz = NULL;
+ } 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--) {
+ 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);
+
+ ret = mem_cgroup_move_parent(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;
+ 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;
+ }
+ 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;
+}
+
+struct mem_cgroup_idx_data {
+ s64 val;
+ enum mem_cgroup_stat_index idx;
+};
+
+static int
+mem_cgroup_get_idx_stat(struct mem_cgroup *mem, void *data)
+{
+ struct mem_cgroup_idx_data *d = data;
+ d->val += mem_cgroup_read_stat(mem, d->idx);
+ return 0;
+}
+
+static void
+mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem,
+ enum mem_cgroup_stat_index idx, s64 *val)
+{
+ struct mem_cgroup_idx_data d;
+ d.idx = idx;
+ d.val = 0;
+ mem_cgroup_walk_tree(mem, &d, mem_cgroup_get_idx_stat);
+ *val = d.val;
+}
+
+static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap)
+{
+ u64 idx_val, 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);
+ }
+
+ mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_CACHE, &idx_val);
+ val = idx_val;
+ mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_RSS, &idx_val);
+ val += idx_val;
+
+ if (swap) {
+ mem_cgroup_get_recursive_idx_stat(mem,
+ MEM_CGROUP_STAT_SWAPOUT, &idx_val);
+ val += idx_val;
+ }
+
+ 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_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"},
+ {"inactive_anon", "total_inactive_anon"},
+ {"active_anon", "total_active_anon"},
+ {"inactive_file", "total_inactive_file"},
+ {"active_file", "total_active_file"},
+ {"unevictable", "total_unevictable"}
+};
+
+
+static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data)
+{
+ struct mcs_total_stat *s = data;
+ 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_stat(mem, MEM_CGROUP_STAT_PGPGIN_COUNT);
+ s->stat[MCS_PGPGIN] += val;
+ val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGOUT_COUNT);
+ 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;
+ }
+
+ /* 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;
+ return 0;
+}
+
+static void
+mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
+{
+ mem_cgroup_walk_tree(mem, s, mem_cgroup_get_local_stat);
+}
+
+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);
}
-int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
- gfp_t gfp_mask)
+static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
+ u64 val)
{
- if (mem_cgroup_subsys.disabled)
- return 0;
+ struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+ struct mem_cgroup *parent;
- /*
- * 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.)
- */
- if (!(gfp_mask & __GFP_WAIT)) {
- struct page_cgroup *pc;
+ if (val > 100)
+ return -EINVAL;
- lock_page_cgroup(page);
- pc = page_get_page_cgroup(page);
- if (pc) {
- VM_BUG_ON(pc->page != page);
- VM_BUG_ON(!pc->mem_cgroup);
- unlock_page_cgroup(page);
- return 0;
- }
- unlock_page_cgroup(page);
+ 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;
}
- if (unlikely(!mm))
- mm = &init_mm;
+ spin_lock(&memcg->reclaim_param_lock);
+ memcg->swappiness = val;
+ spin_unlock(&memcg->reclaim_param_lock);
- return mem_cgroup_charge_common(page, mm, gfp_mask,
- MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
+ cgroup_unlock();
+
+ return 0;
}
-/*
- * uncharge if !page_mapped(page)
- */
-static void
-__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
+static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
{
- struct page_cgroup *pc;
- struct mem_cgroup *mem;
- struct mem_cgroup_per_zone *mz;
- unsigned long flags;
+ struct mem_cgroup_threshold_ary *t;
+ u64 usage;
+ int i;
- if (mem_cgroup_subsys.disabled)
- return;
+ rcu_read_lock();
+ if (!swap)
+ t = rcu_dereference(memcg->thresholds.primary);
+ else
+ t = rcu_dereference(memcg->memsw_thresholds.primary);
- /*
- * Check if our page_cgroup is valid
- */
- lock_page_cgroup(page);
- pc = page_get_page_cgroup(page);
- if (unlikely(!pc))
+ if (!t)
goto unlock;
- VM_BUG_ON(pc->page != page);
+ usage = mem_cgroup_usage(memcg, swap);
- if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
- && ((pc->flags & PAGE_CGROUP_FLAG_CACHE)
- || page_mapped(page)))
- goto unlock;
+ /*
+ * 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;
- mz = page_cgroup_zoneinfo(pc);
- spin_lock_irqsave(&mz->lru_lock, flags);
- __mem_cgroup_remove_list(mz, pc);
- spin_unlock_irqrestore(&mz->lru_lock, flags);
+ /*
+ * 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);
- page_assign_page_cgroup(page, NULL);
- unlock_page_cgroup(page);
+ /* i = current_threshold + 1 */
+ i++;
- mem = pc->mem_cgroup;
- res_counter_uncharge(&mem->res, PAGE_SIZE);
- css_put(&mem->css);
+ /*
+ * 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);
- kmem_cache_free(page_cgroup_cache, pc);
- return;
+ /* Update current_threshold */
+ t->current_threshold = i - 1;
unlock:
- unlock_page_cgroup(page);
+ rcu_read_unlock();
}
-void mem_cgroup_uncharge_page(struct page *page)
+static void mem_cgroup_threshold(struct mem_cgroup *memcg)
{
- __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
+ __mem_cgroup_threshold(memcg, false);
+ if (do_swap_account)
+ __mem_cgroup_threshold(memcg, true);
}
-void mem_cgroup_uncharge_cache_page(struct page *page)
+static int compare_thresholds(const void *a, const void *b)
{
- VM_BUG_ON(page_mapped(page));
- __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
+ const struct mem_cgroup_threshold *_a = a;
+ const struct mem_cgroup_threshold *_b = b;
+
+ return _a->threshold - _b->threshold;
}
-/*
- * Before starting migration, account against new page.
- */
-int mem_cgroup_prepare_migration(struct page *page, struct page *newpage)
+static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem, void *data)
{
- struct page_cgroup *pc;
- struct mem_cgroup *mem = NULL;
- enum charge_type ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
- int ret = 0;
-
- if (mem_cgroup_subsys.disabled)
- return 0;
+ struct mem_cgroup_eventfd_list *ev;
- lock_page_cgroup(page);
- pc = page_get_page_cgroup(page);
- if (pc) {
- mem = pc->mem_cgroup;
- css_get(&mem->css);
- if (pc->flags & PAGE_CGROUP_FLAG_CACHE) {
- if (page_is_file_cache(page))
- ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
- else
- ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
- }
- }
- unlock_page_cgroup(page);
- if (mem) {
- ret = mem_cgroup_charge_common(newpage, NULL, GFP_KERNEL,
- ctype, mem);
- css_put(&mem->css);
- }
- return ret;
+ list_for_each_entry(ev, &mem->oom_notify, list)
+ eventfd_signal(ev->eventfd, 1);
+ return 0;
}
-/* remove redundant charge if migration failed*/
-void mem_cgroup_end_migration(struct page *newpage)
+static void mem_cgroup_oom_notify(struct mem_cgroup *mem)
{
- /*
- * At success, page->mapping is not NULL.
- * special rollback care is necessary when
- * 1. at migration failure. (newpage->mapping is cleared in this case)
- * 2. the newpage was moved but not remapped again because the task
- * exits and the newpage is obsolete. In this case, the new page
- * may be a swapcache. So, we just call mem_cgroup_uncharge_page()
- * always for avoiding mess. The page_cgroup will be removed if
- * unnecessary. File cache pages is still on radix-tree. Don't
- * care it.
- */
- if (!newpage->mapping)
- __mem_cgroup_uncharge_common(newpage,
- MEM_CGROUP_CHARGE_TYPE_FORCE);
- else if (PageAnon(newpage))
- mem_cgroup_uncharge_page(newpage);
+ mem_cgroup_walk_tree(mem, NULL, mem_cgroup_oom_notify_cb);
}
-/*
- * A call to try to shrink memory usage under specified resource controller.
- * This is typically used for page reclaiming for shmem for reducing side
- * effect of page allocation from shmem, which is used by some mem_cgroup.
- */
-int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)
+static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
+ struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
{
- struct mem_cgroup *mem;
- int progress = 0;
- int retry = MEM_CGROUP_RECLAIM_RETRIES;
-
- if (mem_cgroup_subsys.disabled)
- return 0;
- if (!mm)
- return 0;
+ 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();
- rcu_read_lock();
- mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
- if (unlikely(!mem)) {
- rcu_read_unlock();
- return 0;
- }
- css_get(&mem->css);
- rcu_read_unlock();
+ usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
- do {
- progress = try_to_free_mem_cgroup_pages(mem, gfp_mask);
- progress += res_counter_check_under_limit(&mem->res);
- } while (!progress && --retry);
+ /* Check if a threshold crossed before adding a new one */
+ if (thresholds->primary)
+ __mem_cgroup_threshold(memcg, type == _MEMSWAP);
- css_put(&mem->css);
- if (!retry)
- return -ENOMEM;
- return 0;
-}
+ size = thresholds->primary ? thresholds->primary->size + 1 : 1;
-int mem_cgroup_resize_limit(struct mem_cgroup *memcg, unsigned long long val)
-{
+ /* 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;
- int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
- int progress;
- int ret = 0;
+ /* Copy thresholds (if any) to new array */
+ if (thresholds->primary) {
+ memcpy(new->entries, thresholds->primary->entries, (size - 1) *
+ sizeof(struct mem_cgroup_threshold));
+ }
- while (res_counter_set_limit(&memcg->res, val)) {
- if (signal_pending(current)) {
- ret = -EINTR;
- break;
- }
- if (!retry_count) {
- ret = -EBUSY;
- break;
+ /* 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;
}
- progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL);
- if (!progress)
- retry_count--;
}
- return ret;
-}
+ /* Free old spare buffer and save old primary buffer as spare */
+ kfree(thresholds->spare);
+ thresholds->spare = thresholds->primary;
-/*
- * This routine traverse page_cgroup in given list and drop them all.
- * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
- */
-#define FORCE_UNCHARGE_BATCH (128)
-static void mem_cgroup_force_empty_list(struct mem_cgroup *mem,
- struct mem_cgroup_per_zone *mz,
- enum lru_list lru)
-{
- struct page_cgroup *pc;
- struct page *page;
- int count = FORCE_UNCHARGE_BATCH;
- unsigned long flags;
- struct list_head *list;
+ rcu_assign_pointer(thresholds->primary, new);
- list = &mz->lists[lru];
+ /* To be sure that nobody uses thresholds */
+ synchronize_rcu();
- spin_lock_irqsave(&mz->lru_lock, flags);
- while (!list_empty(list)) {
- pc = list_entry(list->prev, struct page_cgroup, lru);
- page = pc->page;
- get_page(page);
- spin_unlock_irqrestore(&mz->lru_lock, flags);
- /*
- * Check if this page is on LRU. !LRU page can be found
- * if it's under page migration.
- */
- if (PageLRU(page)) {
- __mem_cgroup_uncharge_common(page,
- MEM_CGROUP_CHARGE_TYPE_FORCE);
- put_page(page);
- if (--count <= 0) {
- count = FORCE_UNCHARGE_BATCH;
- cond_resched();
- }
- } else
- cond_resched();
- spin_lock_irqsave(&mz->lru_lock, flags);
- }
- spin_unlock_irqrestore(&mz->lru_lock, flags);
+unlock:
+ mutex_unlock(&memcg->thresholds_lock);
+
+ 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)
+static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
+ struct cftype *cft, struct eventfd_ctx *eventfd)
{
- int ret = -EBUSY;
- int node, zid;
+ 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();
- css_get(&mem->css);
/*
- * page reclaim code (kswapd etc..) will move pages between
- * active_list <-> inactive_list while we don't take a lock.
- * So, we have to do loop here until all lists are empty.
+ * Something went wrong if we trying to unregister a threshold
+ * if we don't have thresholds
*/
- while (mem->res.usage > 0) {
- if (atomic_read(&mem->css.cgroup->count) > 0)
- goto out;
- for_each_node_state(node, N_POSSIBLE)
- for (zid = 0; zid < MAX_NR_ZONES; zid++) {
- struct mem_cgroup_per_zone *mz;
- enum lru_list l;
- mz = mem_cgroup_zoneinfo(mem, node, zid);
- for_each_lru(l)
- mem_cgroup_force_empty_list(mem, mz, l);
- }
+ BUG_ON(!thresholds);
+
+ 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++;
}
- ret = 0;
-out:
- css_put(&mem->css);
- return ret;
+
+ 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;
+ rcu_assign_pointer(thresholds->primary, new);
+
+ /* To be sure that nobody uses thresholds */
+ synchronize_rcu();
+
+ mutex_unlock(&memcg->thresholds_lock);
}
-static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
+static int mem_cgroup_oom_register_event(struct cgroup *cgrp,
+ struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
{
- return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res,
- cft->private);
+ 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;
}
-/*
- * The user of this function is...
- * RES_LIMIT.
- */
-static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
- const char *buffer)
+
+static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
+ struct cftype *cft, struct eventfd_ctx *eventfd)
{
- struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
- unsigned long long val;
- int ret;
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
+ struct mem_cgroup_eventfd_list *ev, *tmp;
+ int type = MEMFILE_TYPE(cft->private);
- switch (cft->private) {
- case RES_LIMIT:
- /* This function does all necessary parse...reuse it */
- ret = res_counter_memparse_write_strategy(buffer, &val);
- if (!ret)
- ret = mem_cgroup_resize_limit(memcg, val);
- break;
- default:
- ret = -EINVAL; /* should be BUG() ? */
- break;
+ 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);
+ }
}
- return ret;
+
+ mutex_unlock(&memcg_oom_mutex);
}
-static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
+static int mem_cgroup_oom_control_read(struct cgroup *cgrp,
+ struct cftype *cft, struct cgroup_map_cb *cb)
{
- struct mem_cgroup *mem;
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
- mem = mem_cgroup_from_cont(cont);
- switch (event) {
- case RES_MAX_USAGE:
- res_counter_reset_max(&mem->res);
- break;
- case RES_FAILCNT:
- res_counter_reset_failcnt(&mem->res);
- break;
- }
+ 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_force_empty_write(struct cgroup *cont, unsigned int event)
+/*
+ */
+static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
+ struct cftype *cft, u64 val)
{
- return mem_cgroup_force_empty(mem_cgroup_from_cont(cont));
-}
-
-static const struct mem_cgroup_stat_desc {
- const char *msg;
- u64 unit;
-} mem_cgroup_stat_desc[] = {
- [MEM_CGROUP_STAT_CACHE] = { "cache", PAGE_SIZE, },
- [MEM_CGROUP_STAT_RSS] = { "rss", PAGE_SIZE, },
- [MEM_CGROUP_STAT_PGPGIN_COUNT] = {"pgpgin", 1, },
- [MEM_CGROUP_STAT_PGPGOUT_COUNT] = {"pgpgout", 1, },
-};
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
+ struct mem_cgroup *parent;
-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 mem_cgroup_stat *stat = &mem_cont->stat;
- int i;
+ /* cannot set to root cgroup and only 0 and 1 are allowed */
+ if (!cgrp->parent || !((val == 0) || (val == 1)))
+ return -EINVAL;
- for (i = 0; i < ARRAY_SIZE(stat->cpustat[0].count); i++) {
- s64 val;
+ parent = mem_cgroup_from_cont(cgrp->parent);
- val = mem_cgroup_read_stat(stat, i);
- val *= mem_cgroup_stat_desc[i].unit;
- cb->fill(cb, mem_cgroup_stat_desc[i].msg, val);
+ 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;
}
- /* showing # of active pages */
+ mem->oom_kill_disable = val;
+ cgroup_unlock();
+ return 0;
+}
+
+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,
+ },
{
- unsigned long active_anon, inactive_anon;
- unsigned long active_file, inactive_file;
-
- inactive_anon = mem_cgroup_get_all_zonestat(mem_cont,
- LRU_INACTIVE_ANON);
- active_anon = mem_cgroup_get_all_zonestat(mem_cont,
- LRU_ACTIVE_ANON);
- inactive_file = mem_cgroup_get_all_zonestat(mem_cont,
- LRU_INACTIVE_FILE);
- active_file = mem_cgroup_get_all_zonestat(mem_cont,
- LRU_ACTIVE_FILE);
- cb->fill(cb, "active_anon", (active_anon) * PAGE_SIZE);
- cb->fill(cb, "inactive_anon", (inactive_anon) * PAGE_SIZE);
- cb->fill(cb, "active_file", (active_file) * PAGE_SIZE);
- cb->fill(cb, "inactive_file", (inactive_file) * PAGE_SIZE);
- }
- return 0;
-}
+ .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),
+ },
+};
-static struct cftype mem_cgroup_files[] = {
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+static struct cftype memsw_cgroup_files[] = {
{
- .name = "usage_in_bytes",
- .private = RES_USAGE,
+ .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 = "max_usage_in_bytes",
- .private = RES_MAX_USAGE,
+ .name = "memsw.max_usage_in_bytes",
+ .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
.trigger = mem_cgroup_reset,
.read_u64 = mem_cgroup_read,
},
{
- .name = "limit_in_bytes",
- .private = RES_LIMIT,
+ .name = "memsw.limit_in_bytes",
+ .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
.write_string = mem_cgroup_write,
.read_u64 = mem_cgroup_read,
},
{
- .name = "failcnt",
- .private = RES_FAILCNT,
+ .name = "memsw.failcnt",
+ .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
.trigger = mem_cgroup_reset,
.read_u64 = mem_cgroup_read,
},
- {
- .name = "force_empty",
- .trigger = mem_force_empty_write,
- },
- {
- .name = "stat",
- .read_map = mem_control_stat_show,
- },
};
+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;
for (zone = 0; zone < MAX_NR_ZONES; zone++) {
mz = &pn->zoneinfo[zone];
- spin_lock_init(&mz->lru_lock);
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 struct mem_cgroup *mem_cgroup_alloc(void)
{
struct mem_cgroup *mem;
+ int size = sizeof(struct mem_cgroup);
- if (sizeof(*mem) < PAGE_SIZE)
- mem = kmalloc(sizeof(*mem), GFP_KERNEL);
+ /* Can be very big if MAX_NUMNODES is very big */
+ if (size < PAGE_SIZE)
+ mem = kmalloc(size, GFP_KERNEL);
else
- mem = vmalloc(sizeof(*mem));
+ mem = vmalloc(size);
- if (mem)
- memset(mem, 0, sizeof(*mem));
+ if (!mem)
+ return NULL;
+
+ memset(mem, 0, size);
+ mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
+ if (!mem->stat) {
+ if (size < PAGE_SIZE)
+ kfree(mem);
+ else
+ vfree(mem);
+ mem = NULL;
+ }
return mem;
}
-static void mem_cgroup_free(struct mem_cgroup *mem)
+/*
+ * 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)
{
- if (sizeof(*mem) < PAGE_SIZE)
+ 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 struct cgroup_subsys_state *
-mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
+static void __mem_cgroup_put(struct mem_cgroup *mem, int count)
{
- struct mem_cgroup *mem;
- int node;
+ 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);
+ }
+}
- if (unlikely((cont->parent) == NULL)) {
- mem = &init_mem_cgroup;
- page_cgroup_cache = KMEM_CACHE(page_cgroup, SLAB_PANIC);
- } else {
- mem = mem_cgroup_alloc();
- if (!mem)
- return ERR_PTR(-ENOMEM);
+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;
- res_counter_init(&mem->res);
+ 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;
+ root_mem_cgroup = mem;
+ if (mem_cgroup_soft_limit_tree_init())
+ goto free_out;
+ 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_stock_cpu_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;
+ spin_lock_init(&mem->reclaim_param_lock);
+ 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:
- for_each_node_state(node, N_POSSIBLE)
- free_mem_cgroup_per_zone_info(mem, node);
- if (cont->parent != NULL)
- mem_cgroup_free(mem);
- return ERR_PTR(-ENOMEM);
+ __mem_cgroup_free(mem);
+ root_mem_cgroup = NULL;
+ return ERR_PTR(error);
}
-static void mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
+static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
struct cgroup *cont)
{
struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
- mem_cgroup_force_empty(mem);
+
+ return mem_cgroup_force_empty(mem, false);
}
static void mem_cgroup_destroy(struct cgroup_subsys *ss,
struct cgroup *cont)
{
- int node;
struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
- for_each_node_state(node, N_POSSIBLE)
- free_mem_cgroup_per_zone_info(mem, node);
-
- mem_cgroup_free(mem_cgroup_from_cont(cont));
+ mem_cgroup_put(mem);
}
static int mem_cgroup_populate(struct cgroup_subsys *ss,
struct cgroup *cont)
{
- return cgroup_add_files(cont, ss, mem_cgroup_files,
- ARRAY_SIZE(mem_cgroup_files));
+ 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;
+ VM_BUG_ON(test_bit(CSS_ROOT, &mem->css.flags));
+ WARN_ON_ONCE(count > INT_MAX);
+ __css_get(&mem->css, (int)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, &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;
+
+ 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)
+{
+ return mem_cgroup_do_precharge(mem_cgroup_count_precharge(mm));
+}
+
+static void mem_cgroup_clear_mc(void)
+{
+ /* we must uncharge all the leftover precharges from mc.to */
+ if (mc.precharge) {
+ __mem_cgroup_cancel_charge(mc.to, mc.precharge);
+ mc.precharge = 0;
+ memcg_oom_recover(mc.to);
+ }
+ /*
+ * 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;
+ memcg_oom_recover(mc.from);
+ }
+ /* we must fixup refcnts and charges */
+ if (mc.moved_swap) {
+ WARN_ON_ONCE(mc.moved_swap > INT_MAX);
+ /* 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);
+ VM_BUG_ON(test_bit(CSS_ROOT, &mc.to->css.flags));
+ __css_put(&mc.to->css, mc.moved_swap);
+ }
+ /* we've already done mem_cgroup_get(mc.to) */
+
+ mc.moved_swap = 0;
+ }
+ mc.from = NULL;
+ mc.to = NULL;
+ mc.moving_task = NULL;
+ wake_up_all(&mc.waitq);
+}
+
+static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
+ struct cgroup *cgroup,
+ struct task_struct *p,
+ bool threadgroup)
+{
+ 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);
+ VM_BUG_ON(mc.moving_task);
+ mc.from = from;
+ mc.to = mem;
+ mc.precharge = 0;
+ mc.moved_charge = 0;
+ mc.moved_swap = 0;
+ mc.moving_task = current;
+
+ 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,
+ bool threadgroup)
+{
+ 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;
+
+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(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();
+ down_read(&mm->mmap_sem);
+ 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 task_struct *p,
+ bool threadgroup)
{
struct mm_struct *mm;
- struct mem_cgroup *mem, *old_mem;
- mm = get_task_mm(p);
- if (mm == NULL)
+ if (!mc.to)
+ /* no need to move charge */
return;
- mem = mem_cgroup_from_cont(cont);
- old_mem = mem_cgroup_from_cont(old_cont);
-
- /*
- * Only thread group leaders are allowed to migrate, the mm_struct is
- * in effect owned by the leader
- */
- if (!thread_group_leader(p))
- goto out;
-
-out:
- mmput(mm);
+ mm = get_task_mm(p);
+ if (mm) {
+ mem_cgroup_move_charge(mm);
+ mmput(mm);
+ }
+ mem_cgroup_clear_mc();
}
+#else /* !CONFIG_MMU */
+static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
+ struct cgroup *cgroup,
+ struct task_struct *p,
+ bool threadgroup)
+{
+ return 0;
+}
+static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
+ struct cgroup *cgroup,
+ struct task_struct *p,
+ bool threadgroup)
+{
+}
+static void mem_cgroup_move_task(struct cgroup_subsys *ss,
+ struct cgroup *cont,
+ struct cgroup *old_cont,
+ struct task_struct *p,
+ bool threadgroup)
+{
+}
+#endif
struct cgroup_subsys mem_cgroup_subsys = {
.name = "memory",
.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 disable_swap_account(char *s)
+{
+ really_do_swap_account = 0;
+ return 1;
+}
+__setup("noswapaccount", disable_swap_account);
+#endif