X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=mm%2Fmemcontrol.c;h=c8569bc298ffc77c5a2627b5a4d2fd2a42b91742;hb=a52116aba5b3eed0ee41f70b794cc1937acd5cb8;hp=13e9e7d8e49e7f9004a66fd8d59a55b65e313f5c;hpb=b9c565d5a29a795f970b4a1340393d8fc6722fb9;p=safe%2Fjmp%2Flinux-2.6 diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 13e9e7d..c8569bc 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6,6 +6,10 @@ * Copyright 2007 OpenVZ SWsoft Inc * Author: Pavel Emelianov * + * 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 @@ -21,20 +25,53 @@ #include #include #include +#include +#include #include #include #include #include #include +#include +#include +#include +#include #include +#include #include +#include +#include #include #include +#include +#include +#include +#include +#include "internal.h" #include -struct cgroup_subsys mem_cgroup_subsys; -static const int MEM_CGROUP_RECLAIM_RETRIES = 5; +struct cgroup_subsys mem_cgroup_subsys __read_mostly; +#define MEM_CGROUP_RECLAIM_RETRIES 5 +struct mem_cgroup *root_mem_cgroup __read_mostly; + +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP +/* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */ +int do_swap_account __read_mostly; +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. @@ -44,58 +81,37 @@ enum mem_cgroup_stat_index { * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss. */ MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */ - MEM_CGROUP_STAT_RSS, /* # of pages charged as 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. */ - -enum mem_cgroup_zstat_index { - MEM_CGROUP_ZSTAT_ACTIVE, - MEM_CGROUP_ZSTAT_INACTIVE, - - NR_MEM_CGROUP_ZSTAT, -}; - struct mem_cgroup_per_zone { /* * spin_lock to protect the per cgroup LRU */ - spinlock_t lru_lock; - struct list_head active_list; - struct list_head inactive_list; - unsigned long count[NR_MEM_CGROUP_ZSTAT]; + 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)]) @@ -109,6 +125,42 @@ struct mem_cgroup_lru_info { }; /* + * 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; +}; + +struct mem_cgroup_threshold_ary { + /* An array index points to threshold just below usage. */ + atomic_t current_threshold; + /* Size of entries[] */ + unsigned int size; + /* Array of thresholds */ + struct mem_cgroup_threshold entries[0]; +}; + +static void mem_cgroup_threshold(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, @@ -126,77 +178,128 @@ struct mem_cgroup { */ 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; -}; -static struct mem_cgroup init_mem_cgroup; + int last_scanned_child; + /* + * Should the accounting and control be hierarchical, per subtree? + */ + bool use_hierarchy; + atomic_t oom_lock; + atomic_t refcnt; -/* - * 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. - */ -#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 + unsigned int swappiness; + + /* 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_threshold_ary *thresholds; + + /* thresholds for mem+swap usage. RCU-protected */ + struct mem_cgroup_threshold_ary *memsw_thresholds; + /* + * 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; +}; + +/* Stuffs for move charges at task migration. */ /* - * A page_cgroup page is associated with every page descriptor. The - * page_cgroup helps us identify information about the cgroup + * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a + * left-shifted bitmap of these types. */ -struct page_cgroup { - struct list_head lru; /* per cgroup LRU list */ - struct page *page; - struct mem_cgroup *mem_cgroup; - int ref_cnt; /* cached, mapped, migrating */ - int flags; +enum move_type { + MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */ + NR_MOVE_TYPE, }; -#define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */ -#define PAGE_CGROUP_FLAG_ACTIVE (0x2) /* page is active in this cgroup */ -static int page_cgroup_nid(struct page_cgroup *pc) -{ - return page_to_nid(pc->page); -} +/* "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), +}; -static enum zone_type page_cgroup_zid(struct page_cgroup *pc) -{ - return page_zonenum(pc->page); -} +/* + * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft + * limit reclaim to prevent infinite loops, if they ever occur. + */ +#define MEM_CGROUP_MAX_RECLAIM_LOOPS (100) +#define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS (2) enum charge_type { MEM_CGROUP_CHARGE_TYPE_CACHE = 0, MEM_CGROUP_CHARGE_TYPE_MAPPED, + MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */ + MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */ + MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */ + MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */ + NR_CHARGE_TYPE, }; +/* 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 MEMFILE_PRIVATE(x, val) (((x) << 16) | (val)) +#define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff) +#define MEMFILE_ATTR(val) ((val) & 0xffff) + /* - * 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); -} +#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) @@ -204,6 +307,11 @@ 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) { @@ -211,760 +319,3332 @@ 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 mem_cgroup_zstat_index 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); -static struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) -{ - return container_of(task_subsys_state(p, mem_cgroup_subsys_id), - struct mem_cgroup, css); + return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; } -void mm_init_cgroup(struct mm_struct *mm, 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) { - struct mem_cgroup *mem; + struct rb_node **p = &mctz->rb_root.rb_node; + struct rb_node *parent = NULL; + struct mem_cgroup_per_zone *mz_node; - mem = mem_cgroup_from_task(p); - css_get(&mem->css); - mm->mem_cgroup = mem; + 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; } -void mm_free_cgroup(struct mm_struct *mm) +static void +__mem_cgroup_remove_exceeded(struct mem_cgroup *mem, + struct mem_cgroup_per_zone *mz, + struct mem_cgroup_tree_per_zone *mctz) { - css_put(&mm->mem_cgroup->css); + if (!mz->on_tree) + return; + rb_erase(&mz->tree_node, &mctz->rb_root); + mz->on_tree = false; } -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); + spin_lock(&mctz->lock); + __mem_cgroup_remove_exceeded(mem, mz, mctz); + spin_unlock(&mctz->lock); } -static void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc) + +static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page) { - VM_BUG_ON(!page_cgroup_locked(page)); - page->page_cgroup = ((unsigned long)pc | 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); + } + } } -struct page_cgroup *page_get_page_cgroup(struct page *page) +static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem) { - return (struct page_cgroup *) (page->page_cgroup & ~PAGE_CGROUP_LOCK); + 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 void lock_page_cgroup(struct page *page) +static inline unsigned long mem_cgroup_get_excess(struct mem_cgroup *mem) { - bit_spin_lock(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 page_cgroup *pc) +static struct mem_cgroup_per_zone * +mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) { - int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE; - struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc); + struct mem_cgroup_per_zone *mz; - if (from) - MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) -= 1; - else - MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) -= 1; + spin_lock(&mctz->lock); + mz = __mem_cgroup_largest_soft_limit_node(mctz); + spin_unlock(&mctz->lock); + return mz; +} - mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, false); - list_del_init(&pc->lru); +static s64 mem_cgroup_read_stat(struct mem_cgroup *mem, + enum mem_cgroup_stat_index idx) +{ + int cpu; + s64 val = 0; + + for_each_possible_cpu(cpu) + val += per_cpu(mem->stat->count[idx], cpu); + return val; } -static void __mem_cgroup_add_list(struct page_cgroup *pc) +static s64 mem_cgroup_local_usage(struct mem_cgroup *mem) { - int to = pc->flags & PAGE_CGROUP_FLAG_ACTIVE; - struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc); + s64 ret; - if (!to) { - MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) += 1; - list_add(&pc->lru, &mz->inactive_list); - } else { - MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) += 1; - list_add(&pc->lru, &mz->active_list); - } - mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, true); + ret = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS); + ret += mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE); + return ret; } -static void __mem_cgroup_move_lists(struct page_cgroup *pc, bool active) +static void mem_cgroup_swap_statistics(struct mem_cgroup *mem, + bool charge) { - int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE; - struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc); + int val = (charge) ? 1 : -1; + this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_SWAPOUT], val); +} + +static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, + struct page_cgroup *pc, + bool charge) +{ + int val = (charge) ? 1 : -1; + + preempt_disable(); - if (from) - MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) -= 1; + if (PageCgroupCache(pc)) + __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], val); else - MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) -= 1; + __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], val); - if (active) { - MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) += 1; - pc->flags |= PAGE_CGROUP_FLAG_ACTIVE; - list_move(&pc->lru, &mz->active_list); - } else { - MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) += 1; - pc->flags &= ~PAGE_CGROUP_FLAG_ACTIVE; - list_move(&pc->lru, &mz->inactive_list); - } + 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; } -/* - * This routine assumes that the appropriate zone's lru lock is already held - */ -void mem_cgroup_move_lists(struct page *page, bool active) +static bool __memcg_event_check(struct mem_cgroup *mem, int event_mask_shift) { - struct page_cgroup *pc; - struct mem_cgroup_per_zone *mz; - unsigned long flags; + s64 val; - pc = page_get_page_cgroup(page); - if (!pc) - return; + val = this_cpu_read(mem->stat->count[MEM_CGROUP_EVENTS]); - 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); + return !(val & ((1 << event_mask_shift) - 1)); } /* - * Calculate mapped_ratio under memory controller. This will be used in - * vmscan.c for deteremining we have to reclaim mapped pages. + * Check events in order. + * */ -int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem) +static void memcg_check_events(struct mem_cgroup *mem, struct page *page) +{ + /* threshold event is triggered in finer grain than soft limit */ + if (unlikely(__memcg_event_check(mem, THRESHOLDS_EVENTS_THRESH))) { + mem_cgroup_threshold(mem); + if (unlikely(__memcg_event_check(mem, SOFTLIMIT_EVENTS_THRESH))) + mem_cgroup_update_tree(mem, page); + } +} + +static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) { - long total, rss; + 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) +{ /* - * usage is recorded in bytes. But, here, we assume the number of - * physical pages can be represented by "long" on any arch. + * 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. */ - 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); + if (unlikely(!p)) + return NULL; + + return container_of(task_subsys_state(p, mem_cgroup_subsys_id), + struct mem_cgroup, css); } -/* - * This function is called from vmscan.c. In page reclaiming loop. balance - * between active and inactive list is calculated. For memory controller - * page reclaiming, we should use using mem_cgroup's imbalance rather than - * zone's global lru imbalance. - */ -long mem_cgroup_reclaim_imbalance(struct mem_cgroup *mem) +static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) { - unsigned long active, inactive; - /* active and inactive are the number of pages. 'long' is ok.*/ - active = mem_cgroup_get_all_zonestat(mem, MEM_CGROUP_ZSTAT_ACTIVE); - inactive = mem_cgroup_get_all_zonestat(mem, MEM_CGROUP_ZSTAT_INACTIVE); - return (long) (active / (inactive + 1)); + struct mem_cgroup *mem = NULL; + + if (!mm) + return NULL; + /* + * Because we have no locks, mm->owner's may be being moved to other + * cgroup. We use css_tryget() here even if this looks + * pessimistic (rather than adding locks here). + */ + rcu_read_lock(); + do { + mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); + if (unlikely(!mem)) + break; + } while (!css_tryget(&mem->css)); + rcu_read_unlock(); + return mem; } /* - * 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_active(struct mem_cgroup *mem, - struct zone *zone, int priority) +void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru) { - long nr_active; - 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_active = MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE); - return (nr_active >> priority); + 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; } -long mem_cgroup_calc_reclaim_inactive(struct mem_cgroup *mem, - struct zone *zone, int priority) +void mem_cgroup_del_lru(struct page *page) { - long nr_inactive; - int nid = zone->zone_pgdat->node_id; - int zid = zone_idx(zone); - struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid); - - nr_inactive = MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE); - return (nr_inactive >> priority); + 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) +void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru) { - unsigned long nr_taken = 0; - struct page *page; - unsigned long scan; - LIST_HEAD(pc_list); - struct list_head *src; - struct page_cgroup *pc, *tmp; - int nid = z->zone_pgdat->node_id; - int zid = zone_idx(z); struct mem_cgroup_per_zone *mz; + struct page_cgroup *pc; - mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); - if (active) - src = &mz->active_list; - else - src = &mz->inactive_list; - + if (mem_cgroup_disabled()) + return; - 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; + 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]); +} - if (unlikely(!PageLRU(page))) +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; + unsigned long scan; + LIST_HEAD(pc_list); + struct list_head *src; + struct page_cgroup *pc, *tmp; + 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 ret; + + BUG_ON(!mem_cont); + mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); + src = &mz->lists[lru]; + + scan = 0; + list_for_each_entry_safe_reverse(pc, tmp, src, lru) { + if (scan >= nr_to_scan) + break; + + page = pc->page; + if (unlikely(!PageCgroupUsed(pc))) + continue; + if (unlikely(!PageLRU(page))) + continue; + + scan++; + ret = __isolate_lru_page(page, mode, file); + switch (ret) { + case 0: + list_move(&page->lru, dst); + mem_cgroup_del_lru(page); + nr_taken++; + break; + case -EBUSY: + /* we don't affect global LRU but rotate in our LRU */ + mem_cgroup_rotate_lru_list(page, page_lru(page)); + break; + default: + break; + } + } + + *scanned = scan; + return nr_taken; +} + +#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) +{ + 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; + + 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; + /* + * Need a buffer in BSS, can't rely on allocations. The code relies + * on the assumption that OOM is serialized for memory controller. + * If this assumption is broken, revisit this code. + */ + static char memcg_name[PATH_MAX]; + int ret; + + if (!memcg || !p) + return; + + + rcu_read_lock(); + + mem_cgrp = memcg->css.cgroup; + task_cgrp = task_cgroup(p, mem_cgroup_subsys_id); + + ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX); + if (ret < 0) { + /* + * Unfortunately, we are unable to convert to a useful name + * But we'll still print out the usage information + */ + rcu_read_unlock(); + goto done; + } + rcu_read_unlock(); + + printk(KERN_INFO "Task in %s killed", memcg_name); + + rcu_read_lock(); + ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX); + if (ret < 0) { + rcu_read_unlock(); + goto done; + } + rcu_read_unlock(); + + /* + * Continues from above, so we don't need an KERN_ level + */ + printk(KERN_CONT " as a result of limit of %s\n", memcg_name); +done: + + printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n", + res_counter_read_u64(&memcg->res, RES_USAGE) >> 10, + res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10, + res_counter_read_u64(&memcg->res, RES_FAILCNT)); + printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, " + "failcnt %llu\n", + res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10, + res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10, + res_counter_read_u64(&memcg->memsw, RES_FAILCNT)); +} + +/* + * This function returns the number of memcg under hierarchy tree. Returns + * 1(self count) if no children. + */ +static int mem_cgroup_count_children(struct mem_cgroup *mem) +{ + int num = 0; + mem_cgroup_walk_tree(mem, &num, mem_cgroup_count_children_cb); + return num; +} + +/* + * Visit the first child (need not be the first child as per the ordering + * of the cgroup list, since we track last_scanned_child) of @mem and use + * that to reclaim free pages from. + */ +static struct mem_cgroup * +mem_cgroup_select_victim(struct mem_cgroup *root_mem) +{ + struct mem_cgroup *ret = NULL; + struct cgroup_subsys_state *css; + int nextid, found; + + if (!root_mem->use_hierarchy) { + css_get(&root_mem->css); + ret = root_mem; + } + + while (!ret) { + rcu_read_lock(); + nextid = root_mem->last_scanned_child + 1; + css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css, + &found); + if (css && css_tryget(css)) + ret = container_of(css, struct mem_cgroup, css); + + rcu_read_unlock(); + /* Updates scanning parameter */ + 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); + +/* + * 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) +{ + DEFINE_WAIT(wait); + bool locked; + + /* 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. + */ + if (!locked) + prepare_to_wait(&memcg_oom_waitq, &wait, TASK_KILLABLE); + mutex_unlock(&memcg_oom_mutex); + + if (locked) + mem_cgroup_out_of_memory(mem, mask); + else { + schedule(); + finish_wait(&memcg_oom_waitq, &wait); + } + mutex_lock(&memcg_oom_mutex); + mem_cgroup_oom_unlock(mem); + /* + * Here, we use global waitq .....more fine grained waitq ? + * Assume following hierarchy. + * A/ + * 01 + * 02 + * assume OOM happens both in A and 01 at the same time. Tthey are + * mutually exclusive by lock. (kill in 01 helps A.) + * When we use per memcg waitq, we have to wake up waiters on A and 02 + * in addtion to waiters on 01. We use global waitq for avoiding mess. + * It will not be a big problem. + * (And a task may be moved to other groups while it's waiting for OOM.) + */ + wake_up_all(&memcg_oom_waitq); + 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; + /* + * 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 (!current->memcg_batch.do_batch || test_thread_flag(TIF_MEMDIE)) + goto direct_uncharge; + + 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; + /* + * 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); + 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: + if (page_mapped(page)) + 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); + /* 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 mem_cgroup **ptr) +{ + struct page_cgroup *pc; + struct mem_cgroup *mem = NULL; + 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); + } + unlock_page_cgroup(pc); + + *ptr = mem; + if (mem) { + ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, ptr, false); + css_put(&mem->css); + } + 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 *target, *unused; + struct page_cgroup *pc; + enum charge_type ctype; + + if (!mem) + return; + cgroup_exclude_rmdir(&mem->css); + /* at migration success, oldpage->mapping is NULL. */ + if (oldpage->mapping) { + target = oldpage; + unused = NULL; + } else { + target = newpage; + unused = oldpage; + } + + if (PageAnon(target)) + ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED; + else if (page_is_file_cache(target)) + ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; + else + ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM; + + /* unused page is not on radix-tree now. */ + if (unused) + __mem_cgroup_uncharge_common(unused, ctype); + + pc = lookup_page_cgroup(target); + /* + * __mem_cgroup_commit_charge() check PCG_USED bit of page_cgroup. + * So, double-counting is effectively avoided. + */ + __mem_cgroup_commit_charge(mem, pc, ctype); + + /* + * Both of oldpage and newpage are still under lock_page(). + * Then, we don't have to care about race in radix-tree. + * But we have to be careful that this page is unmapped or not. + * + * There is a case for !page_mapped(). At the start of + * migration, oldpage was mapped. But now, it's zapped. + * But we know *target* page is not freed/reused under us. + * mem_cgroup_uncharge_page() does all necessary checks. + */ + if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED) + mem_cgroup_uncharge_page(target); + /* + * 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; + int ret = 0; + int children = mem_cgroup_count_children(memcg); + u64 curusage, oldusage; + + /* + * 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); + + 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; + } + 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; + } + + return ret; +} + +static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, + unsigned long long val) +{ + int retry_count; + u64 memlimit, oldusage, curusage; + int children = mem_cgroup_count_children(memcg); + int ret = -EBUSY; + + /* 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; + } + 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; + } + 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; + } + /* 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; - if (PageActive(page) && !active) { - __mem_cgroup_move_lists(pc, true); - continue; +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; } - if (!PageActive(page) && active) { - __mem_cgroup_move_lists(pc, false); - continue; + 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); } - scan++; - list_move(&pc->lru, &pc_list); - - if (__isolate_lru_page(page, mode) == 0) { - list_move(&page->lru, dst); - nr_taken++; - } } + lru_add_drain(); + /* try move_account...there may be some *locked* pages. */ + goto move_account; +} - list_splice(&pc_list, src); - spin_unlock(&mz->lru_lock); +int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event) +{ + return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true); +} - *scanned = scan; - return nr_taken; + +static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft) +{ + return mem_cgroup_from_cont(cont)->use_hierarchy; } -/* - * 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) +static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft, + u64 val) { - 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; + 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(); /* - * Should page_cgroup's go to their own slab? - * One could optimize the performance of the charging routine - * by saving a bit in the page_flags and using it as a lock - * to see if the cgroup page already has a page_cgroup associated - * with it - */ -retry: - lock_page_cgroup(page); - pc = page_get_page_cgroup(page); - /* - * The page_cgroup exists and - * the page has already been accounted. + * 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 (pc) { - VM_BUG_ON(pc->page != page); - VM_BUG_ON(pc->ref_cnt <= 0); + 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(); - pc->ref_cnt++; - unlock_page_cgroup(page); - goto done; - } - unlock_page_cgroup(page); + return retval; +} - pc = kzalloc(sizeof(struct page_cgroup), gfp_mask); - if (pc == NULL) - goto err; +struct mem_cgroup_idx_data { + s64 val; + enum mem_cgroup_stat_index idx; +}; - /* - * We always charge the cgroup the mm_struct belongs to. - * The mm_struct's mem_cgroup changes on task migration if the - * thread group leader migrates. It's possible that mm is not - * set, if so charge the init_mm (happens for pagecache usage). - */ - if (!mm) - mm = &init_mm; +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; +} - rcu_read_lock(); - mem = rcu_dereference(mm->mem_cgroup); - /* - * For every charge from the cgroup, increment reference count - */ - css_get(&mem->css); - rcu_read_unlock(); +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; +} - while (res_counter_charge(&mem->res, PAGE_SIZE)) { - if (!(gfp_mask & __GFP_WAIT)) - goto out; +static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap) +{ + u64 idx_val, val; - if (try_to_free_mem_cgroup_pages(mem, gfp_mask)) - continue; + 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); + } - /* - * 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 (res_counter_check_under_limit(&mem->res)) - continue; + 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 (!nr_retries--) { - mem_cgroup_out_of_memory(mem, gfp_mask); - goto out; - } - congestion_wait(WRITE, HZ/10); + if (swap) { + mem_cgroup_get_recursive_idx_stat(mem, + MEM_CGROUP_STAT_SWAPOUT, &idx_val); + val += idx_val; } - pc->ref_cnt = 1; - pc->mem_cgroup = mem; - pc->page = page; - pc->flags = PAGE_CGROUP_FLAG_ACTIVE; - if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE) - pc->flags |= PAGE_CGROUP_FLAG_CACHE; - - lock_page_cgroup(page); - if (page_get_page_cgroup(page)) { - unlock_page_cgroup(page); + 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; /* - * Another charge has been added to this page already. - * We take lock_page_cgroup(page) again and read - * page->cgroup, increment refcnt.... just retry is OK. + * For memsw, soft limits are hard to implement in terms + * of semantics, for now, we support soft limits for + * control without swap */ - res_counter_uncharge(&mem->res, PAGE_SIZE); - css_put(&mem->css); - kfree(pc); - goto retry; + if (type == _MEM) + ret = res_counter_set_soft_limit(&memcg->res, val); + else + ret = -EINVAL; + break; + default: + ret = -EINVAL; /* should be BUG() ? */ + break; } - page_assign_page_cgroup(page, pc); - unlock_page_cgroup(page); + return ret; +} - mz = page_cgroup_zoneinfo(pc); - spin_lock_irqsave(&mz->lru_lock, flags); - __mem_cgroup_add_list(pc); - spin_unlock_irqrestore(&mz->lru_lock, flags); +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; -done: - return 0; + 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: - css_put(&mem->css); - kfree(pc); -err: - return -ENOMEM; + *mem_limit = min_limit; + *memsw_limit = min_memsw_limit; + return; } -int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) +static int mem_cgroup_reset(struct cgroup *cont, unsigned int event) { - return mem_cgroup_charge_common(page, mm, gfp_mask, - MEM_CGROUP_CHARGE_TYPE_MAPPED); + 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; } -int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, - gfp_t gfp_mask) +static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp, + struct cftype *cft) { - if (!mm) - mm = &init_mm; - return mem_cgroup_charge_common(page, mm, gfp_mask, - MEM_CGROUP_CHARGE_TYPE_CACHE); + return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate; } -/* - * Uncharging is always a welcome operation, we never complain, simply - * uncharge. - */ -void mem_cgroup_uncharge_page(struct page *page) +#ifdef CONFIG_MMU +static int mem_cgroup_move_charge_write(struct cgroup *cgrp, + struct cftype *cft, u64 val) { - struct page_cgroup *pc; - struct mem_cgroup *mem; - struct mem_cgroup_per_zone *mz; - unsigned long flags; + struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); + if (val >= (1 << NR_MOVE_TYPE)) + return -EINVAL; /* - * Check if our page_cgroup is valid + * 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. */ - lock_page_cgroup(page); - pc = page_get_page_cgroup(page); - if (!pc) - goto unlock; + cgroup_lock(); + mem->move_charge_at_immigrate = val; + cgroup_unlock(); - VM_BUG_ON(pc->page != page); - VM_BUG_ON(pc->ref_cnt <= 0); + return 0; +} +#else +static int mem_cgroup_move_charge_write(struct cgroup *cgrp, + struct cftype *cft, u64 val) +{ + return -ENOSYS; +} +#endif - if (--(pc->ref_cnt) == 0) { - page_assign_page_cgroup(page, NULL); - unlock_page_cgroup(page); - mem = pc->mem_cgroup; - css_put(&mem->css); - res_counter_uncharge(&mem->res, PAGE_SIZE); +/* 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, +}; - mz = page_cgroup_zoneinfo(pc); - spin_lock_irqsave(&mz->lru_lock, flags); - __mem_cgroup_remove_list(pc); - spin_unlock_irqrestore(&mz->lru_lock, flags); +struct mcs_total_stat { + s64 stat[NR_MCS_STAT]; +}; - kfree(pc); - return; - } +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"} +}; -unlock: - unlock_page_cgroup(page); -} -/* - * Returns non-zero if a page (under migration) has valid page_cgroup member. - * Refcnt of page_cgroup is incremented. - */ -int mem_cgroup_prepare_migration(struct page *page) +static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data) { - struct page_cgroup *pc; + 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; + } - lock_page_cgroup(page); - pc = page_get_page_cgroup(page); - if (pc) - pc->ref_cnt++; - unlock_page_cgroup(page); - return pc != NULL; + /* 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; } -void mem_cgroup_end_migration(struct page *page) +static void +mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s) { - mem_cgroup_uncharge_page(page); + mem_cgroup_walk_tree(mem, s, mem_cgroup_get_local_stat); } -/* - * We know both *page* and *newpage* are now not-on-LRU and PG_locked. - * And no race with uncharge() routines because page_cgroup for *page* - * has extra one reference by mem_cgroup_prepare_migration. - */ -void mem_cgroup_page_migration(struct page *page, struct page *newpage) +static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft, + struct cgroup_map_cb *cb) { - struct page_cgroup *pc; - struct mem_cgroup_per_zone *mz; - unsigned long flags; + struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont); + struct mcs_total_stat mystat; + int i; - lock_page_cgroup(page); - pc = page_get_page_cgroup(page); - if (!pc) { - unlock_page_cgroup(page); - return; + 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]); } - page_assign_page_cgroup(page, NULL); - unlock_page_cgroup(page); + /* 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); + } - mz = page_cgroup_zoneinfo(pc); - spin_lock_irqsave(&mz->lru_lock, flags); - __mem_cgroup_remove_list(pc); - spin_unlock_irqrestore(&mz->lru_lock, flags); + 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]); + } - pc->page = newpage; - lock_page_cgroup(newpage); - page_assign_page_cgroup(newpage, pc); - unlock_page_cgroup(newpage); +#ifdef CONFIG_DEBUG_VM + cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL)); - mz = page_cgroup_zoneinfo(pc); - spin_lock_irqsave(&mz->lru_lock, flags); - __mem_cgroup_add_list(pc); - spin_unlock_irqrestore(&mz->lru_lock, flags); + { + 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; } -/* - * This routine traverse page_cgroup in given list and drop them all. - * This routine ignores page_cgroup->ref_cnt. - * *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, - int active) +static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft) { - struct page_cgroup *pc; - struct page *page; - int count; - unsigned long flags; - struct list_head *list; + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); - if (active) - list = &mz->active_list; - else - list = &mz->inactive_list; + return get_swappiness(memcg); +} - if (list_empty(list)) - return; -retry: - count = FORCE_UNCHARGE_BATCH; - spin_lock_irqsave(&mz->lru_lock, flags); +static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft, + u64 val) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + struct mem_cgroup *parent; - while (--count && !list_empty(list)) { - pc = list_entry(list->prev, struct page_cgroup, lru); - page = pc->page; - lock_page_cgroup(page); - if (page_get_page_cgroup(page) == pc) { - page_assign_page_cgroup(page, NULL); - unlock_page_cgroup(page); - css_put(&mem->css); - res_counter_uncharge(&mem->res, PAGE_SIZE); - __mem_cgroup_remove_list(pc); - kfree(pc); - } else { - /* racing uncharge: let page go then retry */ - unlock_page_cgroup(page); - break; - } - } + if (val > 100) + return -EINVAL; - spin_unlock_irqrestore(&mz->lru_lock, flags); - if (!list_empty(list)) { - cond_resched(); - goto retry; + 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; } + + spin_lock(&memcg->reclaim_param_lock); + memcg->swappiness = val; + spin_unlock(&memcg->reclaim_param_lock); + + cgroup_unlock(); + + return 0; } -/* - * 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_threshold(struct mem_cgroup *memcg, bool swap) { - int ret = -EBUSY; - int node, zid; + struct mem_cgroup_threshold_ary *t; + u64 usage; + int i; + + rcu_read_lock(); + if (!swap) + t = rcu_dereference(memcg->thresholds); + else + t = rcu_dereference(memcg->memsw_thresholds); + + if (!t) + goto unlock; + + usage = mem_cgroup_usage(memcg, swap); - 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. + * current_threshold points to threshold just below usage. + * If it's not true, a threshold was crossed after last + * call of __mem_cgroup_threshold(). */ - 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; - mz = mem_cgroup_zoneinfo(mem, node, zid); - /* drop all page_cgroup in active_list */ - mem_cgroup_force_empty_list(mem, mz, 1); - /* drop all page_cgroup in inactive_list */ - mem_cgroup_force_empty_list(mem, mz, 0); - } - } - ret = 0; -out: - css_put(&mem->css); - return ret; -} + i = atomic_read(&t->current_threshold); -static int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp) -{ - *tmp = memparse(buf, &buf); - if (*buf != '\0') - return -EINVAL; + /* + * Iterate backward over array of thresholds starting from + * current_threshold and check if a threshold is crossed. + * If none of thresholds below usage is crossed, we read + * only one element of the array here. + */ + for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--) + eventfd_signal(t->entries[i].eventfd, 1); + + /* i = current_threshold + 1 */ + i++; /* - * Round up the value to the closest page size + * 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. */ - *tmp = ((*tmp + PAGE_SIZE - 1) >> PAGE_SHIFT) << PAGE_SHIFT; - return 0; + for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++) + eventfd_signal(t->entries[i].eventfd, 1); + + /* Update current_threshold */ + atomic_set(&t->current_threshold, i - 1); +unlock: + rcu_read_unlock(); } -static ssize_t mem_cgroup_read(struct cgroup *cont, - struct cftype *cft, struct file *file, - char __user *userbuf, size_t nbytes, loff_t *ppos) +static void mem_cgroup_threshold(struct mem_cgroup *memcg) { - return res_counter_read(&mem_cgroup_from_cont(cont)->res, - cft->private, userbuf, nbytes, ppos, - NULL); + __mem_cgroup_threshold(memcg, false); + if (do_swap_account) + __mem_cgroup_threshold(memcg, true); } -static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft, - struct file *file, const char __user *userbuf, - size_t nbytes, loff_t *ppos) +static int compare_thresholds(const void *a, const void *b) { - return res_counter_write(&mem_cgroup_from_cont(cont)->res, - cft->private, userbuf, nbytes, ppos, - mem_cgroup_write_strategy); + const struct mem_cgroup_threshold *_a = a; + const struct mem_cgroup_threshold *_b = b; + + return _a->threshold - _b->threshold; } -static ssize_t mem_force_empty_write(struct cgroup *cont, - struct cftype *cft, struct file *file, - const char __user *userbuf, - size_t nbytes, loff_t *ppos) +static int mem_cgroup_register_event(struct cgroup *cgrp, struct cftype *cft, + struct eventfd_ctx *eventfd, const char *args) { - struct mem_cgroup *mem = mem_cgroup_from_cont(cont); - int ret = mem_cgroup_force_empty(mem); - if (!ret) - ret = nbytes; + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + struct mem_cgroup_threshold_ary *thresholds, *thresholds_new; + int type = MEMFILE_TYPE(cft->private); + u64 threshold, usage; + int size; + int i, ret; + + ret = res_counter_memparse_write_strategy(args, &threshold); + if (ret) + return ret; + + mutex_lock(&memcg->thresholds_lock); + if (type == _MEM) + thresholds = memcg->thresholds; + else if (type == _MEMSWAP) + thresholds = memcg->memsw_thresholds; + else + BUG(); + + usage = mem_cgroup_usage(memcg, type == _MEMSWAP); + + /* Check if a threshold crossed before adding a new one */ + if (thresholds) + __mem_cgroup_threshold(memcg, type == _MEMSWAP); + + if (thresholds) + size = thresholds->size + 1; + else + size = 1; + + /* Allocate memory for new array of thresholds */ + thresholds_new = kmalloc(sizeof(*thresholds_new) + + size * sizeof(struct mem_cgroup_threshold), + GFP_KERNEL); + if (!thresholds_new) { + ret = -ENOMEM; + goto unlock; + } + thresholds_new->size = size; + + /* Copy thresholds (if any) to new array */ + if (thresholds) + memcpy(thresholds_new->entries, thresholds->entries, + thresholds->size * + sizeof(struct mem_cgroup_threshold)); + /* Add new threshold */ + thresholds_new->entries[size - 1].eventfd = eventfd; + thresholds_new->entries[size - 1].threshold = threshold; + + /* Sort thresholds. Registering of new threshold isn't time-critical */ + sort(thresholds_new->entries, size, + sizeof(struct mem_cgroup_threshold), + compare_thresholds, NULL); + + /* Find current threshold */ + atomic_set(&thresholds_new->current_threshold, -1); + for (i = 0; i < size; i++) { + if (thresholds_new->entries[i].threshold < usage) { + /* + * thresholds_new->current_threshold will not be used + * until rcu_assign_pointer(), so it's safe to increment + * it here. + */ + atomic_inc(&thresholds_new->current_threshold); + } + } + + if (type == _MEM) + rcu_assign_pointer(memcg->thresholds, thresholds_new); + else + rcu_assign_pointer(memcg->memsw_thresholds, thresholds_new); + + /* To be sure that nobody uses thresholds before freeing it */ + synchronize_rcu(); + + kfree(thresholds); +unlock: + mutex_unlock(&memcg->thresholds_lock); + return ret; } -/* - * Note: This should be removed if cgroup supports write-only file. - */ -static ssize_t mem_force_empty_read(struct cgroup *cont, - struct cftype *cft, - struct file *file, char __user *userbuf, - size_t nbytes, loff_t *ppos) -{ - return -EINVAL; -} +static int mem_cgroup_unregister_event(struct cgroup *cgrp, struct cftype *cft, + struct eventfd_ctx *eventfd) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + struct mem_cgroup_threshold_ary *thresholds, *thresholds_new; + int type = MEMFILE_TYPE(cft->private); + u64 usage; + int size = 0; + int i, j, ret; + + mutex_lock(&memcg->thresholds_lock); + if (type == _MEM) + thresholds = memcg->thresholds; + else if (type == _MEMSWAP) + thresholds = memcg->memsw_thresholds; + else + BUG(); + + /* + * Something went wrong if we trying to unregister a threshold + * if we don't have thresholds + */ + BUG_ON(!thresholds); + + usage = mem_cgroup_usage(memcg, type == _MEMSWAP); -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, }, -}; + /* Check if a threshold crossed before removing */ + __mem_cgroup_threshold(memcg, type == _MEMSWAP); -static int mem_control_stat_show(struct seq_file *m, void *arg) -{ - struct cgroup *cont = m->private; - struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont); - struct mem_cgroup_stat *stat = &mem_cont->stat; - int i; + /* Calculate new number of threshold */ + for (i = 0; i < thresholds->size; i++) { + if (thresholds->entries[i].eventfd != eventfd) + size++; + } - for (i = 0; i < ARRAY_SIZE(stat->cpustat[0].count); i++) { - s64 val; + /* Set thresholds array to NULL if we don't have thresholds */ + if (!size) { + thresholds_new = NULL; + goto assign; + } - val = mem_cgroup_read_stat(stat, i); - val *= mem_cgroup_stat_desc[i].unit; - seq_printf(m, "%s %lld\n", mem_cgroup_stat_desc[i].msg, - (long long)val); + /* Allocate memory for new array of thresholds */ + thresholds_new = kmalloc(sizeof(*thresholds_new) + + size * sizeof(struct mem_cgroup_threshold), + GFP_KERNEL); + if (!thresholds_new) { + ret = -ENOMEM; + goto unlock; } - /* showing # of active pages */ - { - unsigned long active, inactive; + thresholds_new->size = size; + + /* Copy thresholds and find current threshold */ + atomic_set(&thresholds_new->current_threshold, -1); + for (i = 0, j = 0; i < thresholds->size; i++) { + if (thresholds->entries[i].eventfd == eventfd) + continue; - inactive = mem_cgroup_get_all_zonestat(mem_cont, - MEM_CGROUP_ZSTAT_INACTIVE); - active = mem_cgroup_get_all_zonestat(mem_cont, - MEM_CGROUP_ZSTAT_ACTIVE); - seq_printf(m, "active %ld\n", (active) * PAGE_SIZE); - seq_printf(m, "inactive %ld\n", (inactive) * PAGE_SIZE); + thresholds_new->entries[j] = thresholds->entries[i]; + if (thresholds_new->entries[j].threshold < usage) { + /* + * thresholds_new->current_threshold will not be used + * until rcu_assign_pointer(), so it's safe to increment + * it here. + */ + atomic_inc(&thresholds_new->current_threshold); + } + j++; } - return 0; -} -static const struct file_operations mem_control_stat_file_operations = { - .read = seq_read, - .llseek = seq_lseek, - .release = single_release, -}; +assign: + if (type == _MEM) + rcu_assign_pointer(memcg->thresholds, thresholds_new); + else + rcu_assign_pointer(memcg->memsw_thresholds, thresholds_new); -static int mem_control_stat_open(struct inode *unused, struct file *file) -{ - /* XXX __d_cont */ - struct cgroup *cont = file->f_dentry->d_parent->d_fsdata; + /* To be sure that nobody uses thresholds before freeing it */ + synchronize_rcu(); + + kfree(thresholds); +unlock: + mutex_unlock(&memcg->thresholds_lock); - file->f_op = &mem_control_stat_file_operations; - return single_open(file, mem_control_stat_show, cont); + return ret; } static struct cftype mem_cgroup_files[] = { { .name = "usage_in_bytes", - .private = RES_USAGE, - .read = mem_cgroup_read, + .private = MEMFILE_PRIVATE(_MEM, RES_USAGE), + .read_u64 = mem_cgroup_read, + .register_event = mem_cgroup_register_event, + .unregister_event = mem_cgroup_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 = RES_LIMIT, - .write = mem_cgroup_write, - .read = mem_cgroup_read, + .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 = RES_FAILCNT, - .read = mem_cgroup_read, + .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", - .write = mem_force_empty_write, - .read = mem_force_empty_read, + .trigger = mem_cgroup_force_empty_write, }, { - .name = "stat", - .open = mem_control_stat_open, + .name = "use_hierarchy", + .write_u64 = mem_cgroup_hierarchy_write, + .read_u64 = mem_cgroup_hierarchy_read, }, + { + .name = "swappiness", + .read_u64 = mem_cgroup_swappiness_read, + .write_u64 = mem_cgroup_swappiness_write, + }, + { + .name = "move_charge_at_immigrate", + .read_u64 = mem_cgroup_move_charge_read, + .write_u64 = mem_cgroup_move_charge_write, + }, +}; + +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP +static struct cftype memsw_cgroup_files[] = { + { + .name = "memsw.usage_in_bytes", + .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), + .read_u64 = mem_cgroup_read, + .register_event = mem_cgroup_register_event, + .unregister_event = mem_cgroup_unregister_event, + }, + { + .name = "memsw.max_usage_in_bytes", + .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE), + .trigger = mem_cgroup_reset, + .read_u64 = mem_cgroup_read, + }, + { + .name = "memsw.limit_in_bytes", + .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT), + .write_string = mem_cgroup_write, + .read_u64 = mem_cgroup_read, + }, + { + .name = "memsw.failcnt", + .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT), + .trigger = mem_cgroup_reset, + .read_u64 = mem_cgroup_read, + }, +}; + +static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) +{ + if (!do_swap_account) + return 0; + return cgroup_add_files(cont, ss, memsw_cgroup_files, + ARRAY_SIZE(memsw_cgroup_files)); }; +#else +static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) +{ + return 0; +} +#endif static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) { struct mem_cgroup_per_node *pn; struct mem_cgroup_per_zone *mz; - int zone; + enum lru_list l; + int zone, tmp = node; /* * This routine is called against possible nodes. * But it's BUG to call kmalloc() against offline node. @@ -973,10 +3653,9 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) * never be onlined. It's better to use memory hotplug callback * function. */ - if (node_state(node, N_HIGH_MEMORY)) - pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, node); - else - pn = kmalloc(sizeof(*pn), GFP_KERNEL); + if (!node_state(node, N_NORMAL_MEMORY)) + tmp = -1; + pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp); if (!pn) return 1; @@ -985,9 +3664,11 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) for (zone = 0; zone < MAX_NR_ZONES; zone++) { mz = &pn->zoneinfo[zone]; - INIT_LIST_HEAD(&mz->active_list); - INIT_LIST_HEAD(&mz->inactive_list); - 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; } @@ -997,96 +3678,658 @@ static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) kfree(mem->info.nodeinfo[node]); } -static struct cgroup_subsys_state * -mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) +static struct mem_cgroup *mem_cgroup_alloc(void) { struct mem_cgroup *mem; + int size = sizeof(struct mem_cgroup); + + /* Can be very big if MAX_NUMNODES is very big */ + if (size < PAGE_SIZE) + mem = kmalloc(size, GFP_KERNEL); + else + mem = vmalloc(size); + + 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; +} + +/* + * At destroying mem_cgroup, references from swap_cgroup can remain. + * (scanning all at force_empty is too costly...) + * + * Instead of clearing all references at force_empty, we remember + * the number of reference from swap_cgroup and free mem_cgroup when + * it goes down to 0. + * + * Removal of cgroup itself succeeds regardless of refs from swap. + */ + +static void __mem_cgroup_free(struct mem_cgroup *mem) +{ int node; - if (unlikely((cont->parent) == NULL)) { - mem = &init_mem_cgroup; - init_mm.mem_cgroup = mem; - } else - mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL); + mem_cgroup_remove_from_trees(mem); + free_css_id(&mem_cgroup_subsys, &mem->css); + + for_each_node_state(node, N_POSSIBLE) + free_mem_cgroup_per_zone_info(mem, node); + + free_percpu(mem->stat); + if (sizeof(struct mem_cgroup) < PAGE_SIZE) + kfree(mem); + else + vfree(mem); +} + +static void mem_cgroup_get(struct mem_cgroup *mem) +{ + atomic_inc(&mem->refcnt); +} + +static void __mem_cgroup_put(struct mem_cgroup *mem, int count) +{ + if (atomic_sub_and_test(count, &mem->refcnt)) { + struct mem_cgroup *parent = parent_mem_cgroup(mem); + __mem_cgroup_free(mem); + if (parent) + mem_cgroup_put(parent); + } +} + +static void mem_cgroup_put(struct mem_cgroup *mem) +{ + __mem_cgroup_put(mem, 1); +} + +/* + * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled. + */ +static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem) +{ + if (!mem->res.parent) + return NULL; + return mem_cgroup_from_res_counter(mem->res.parent, res); +} + +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP +static void __init enable_swap_cgroup(void) +{ + if (!mem_cgroup_disabled() && really_do_swap_account) + do_swap_account = 1; +} +#else +static void __init enable_swap_cgroup(void) +{ +} +#endif - if (mem == NULL) - return ERR_PTR(-ENOMEM); +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; +} - res_counter_init(&mem->res); +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; - memset(&mem->info, 0, sizeof(mem->info)); + 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; + } + + 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); + + 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) - kfree(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); - - kfree(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; } -static void mem_cgroup_move_task(struct cgroup_subsys *ss, - struct cgroup *cont, - struct cgroup *old_cont, - struct task_struct *p) +#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) { - struct mm_struct *mm; - struct mem_cgroup *mem, *old_mem; + 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; +} - mm = get_task_mm(p); - if (mm == NULL) - return; +/** + * 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; +}; - mem = mem_cgroup_from_cont(cont); - old_mem = mem_cgroup_from_cont(old_cont); +enum mc_target_type { + MC_TARGET_NONE, /* not used */ + MC_TARGET_PAGE, + MC_TARGET_SWAP, +}; - if (mem == old_mem) - goto out; +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 }; + int usage_count = 0; + bool move_anon = test_bit(MOVE_CHARGE_TYPE_ANON, + &mc.to->move_charge_at_immigrate); + + if (!pte_present(ptent)) { + /* TODO: handle swap of shmes/tmpfs */ + if (pte_none(ptent) || pte_file(ptent)) + return 0; + else if (is_swap_pte(ptent)) { + ent = pte_to_swp_entry(ptent); + if (!move_anon || non_swap_entry(ent)) + return 0; + usage_count = mem_cgroup_count_swap_user(ent, &page); + } + } else { + page = vm_normal_page(vma, addr, ptent); + if (!page || !page_mapped(page)) + return 0; + /* + * TODO: We don't move charges of file(including shmem/tmpfs) + * pages for now. + */ + if (!move_anon || !PageAnon(page)) + return 0; + if (!get_page_unless_zero(page)) + return 0; + usage_count = page_mapcount(page); + } + if (usage_count > 1) { + /* + * TODO: We don't move charges of shared(used by multiple + * processes) pages for now. + */ + if (page) + put_page(page); + 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); + } + /* throught */ + if (ent.val && do_swap_account && !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; + /* TODO: We don't move charges of shmem/tmpfs pages for now. */ + if (vma->vm_flags & VM_SHARED) + 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; + } /* - * Only thread group leaders are allowed to migrate, the mm_struct is - * in effect owned by the leader + * we didn't uncharge from mc.from at mem_cgroup_move_account(), so + * we must uncharge here. */ - if (p->tgid != p->pid) - goto out; + if (mc.moved_charge) { + __mem_cgroup_cancel_charge(mc.from, mc.moved_charge); + mc.moved_charge = 0; + } + /* we must fixup refcnts and charges */ + if (mc.moved_swap) { + 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) */ - css_get(&mem->css); - rcu_assign_pointer(mm->mem_cgroup, mem); - css_put(&old_mem->css); + mc.moved_swap = 0; + } + mc.from = NULL; + mc.to = NULL; + mc.moving_task = NULL; + wake_up_all(&mc.waitq); +} -out: - mmput(mm); +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; + /* TODO: We don't move charges of shmem/tmpfs pages for now. */ + if (vma->vm_flags & VM_SHARED) + 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, + bool threadgroup) +{ + struct mm_struct *mm; + + if (!mc.to) + /* no need to move charge */ + return; + + 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", @@ -1095,6 +4338,19 @@ struct cgroup_subsys mem_cgroup_subsys = { .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