/* memcontrol.c - Memory Controller * * Copyright IBM Corporation, 2007 * Author Balbir Singh * * 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 * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include #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 #include "internal.h" #include #include struct cgroup_subsys mem_cgroup_subsys __read_mostly; #define MEM_CGROUP_RECLAIM_RETRIES 5 struct mem_cgroup *root_mem_cgroup __read_mostly; #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */ int do_swap_account __read_mostly; /* for remember boot option*/ #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED static int really_do_swap_account __initdata = 1; #else static int really_do_swap_account __initdata = 0; #endif #else #define do_swap_account (0) #endif /* * 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. */ enum mem_cgroup_stat_index { /* * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss. */ MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */ MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */ MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */ MEM_CGROUP_STAT_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_STAT_DATA, /* end of data requires synchronization */ /* incremented at every pagein/pageout */ MEM_CGROUP_EVENTS = MEM_CGROUP_STAT_DATA, MEM_CGROUP_ON_MOVE, /* someone is moving account between groups */ MEM_CGROUP_STAT_NSTATS, }; struct mem_cgroup_stat_cpu { s64 count[MEM_CGROUP_STAT_NSTATS]; }; /* * per-zone information in memory controller. */ struct mem_cgroup_per_zone { /* * spin_lock to protect the per cgroup LRU */ struct list_head lists[NR_LRU_LISTS]; unsigned long count[NR_LRU_LISTS]; struct zone_reclaim_stat reclaim_stat; struct rb_node tree_node; /* RB tree node */ unsigned long long usage_in_excess;/* Set to the value by which */ /* the soft limit is exceeded*/ bool on_tree; struct mem_cgroup *mem; /* Back pointer, we cannot */ /* use container_of */ }; /* Macro for accessing counter */ #define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)]) struct mem_cgroup_per_node { struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; }; struct mem_cgroup_lru_info { struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES]; }; /* * Cgroups above their limits are maintained in a RB-Tree, independent of * their hierarchy representation */ struct mem_cgroup_tree_per_zone { struct rb_root rb_root; spinlock_t lock; }; struct mem_cgroup_tree_per_node { struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES]; }; struct mem_cgroup_tree { struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES]; }; static struct mem_cgroup_tree soft_limit_tree __read_mostly; struct mem_cgroup_threshold { struct eventfd_ctx *eventfd; u64 threshold; }; /* For threshold */ struct mem_cgroup_threshold_ary { /* An array index points to threshold just below usage. */ int current_threshold; /* Size of entries[] */ unsigned int size; /* Array of thresholds */ struct mem_cgroup_threshold entries[0]; }; struct mem_cgroup_thresholds { /* Primary thresholds array */ struct mem_cgroup_threshold_ary *primary; /* * Spare threshold array. * This is needed to make mem_cgroup_unregister_event() "never fail". * It must be able to store at least primary->size - 1 entries. */ struct mem_cgroup_threshold_ary *spare; }; /* for OOM */ struct mem_cgroup_eventfd_list { struct list_head list; struct eventfd_ctx *eventfd; }; static void mem_cgroup_threshold(struct mem_cgroup *mem); static void mem_cgroup_oom_notify(struct mem_cgroup *mem); /* * The memory controller data structure. The memory controller controls both * page cache and RSS per cgroup. We would eventually like to provide * statistics based on the statistics developed by Rik Van Riel for clock-pro, * to help the administrator determine what knobs to tune. * * TODO: Add a water mark for the memory controller. Reclaim will begin when * we hit the water mark. May be even add a low water mark, such that * no reclaim occurs from a cgroup at it's low water mark, this is * a feature that will be implemented much later in the future. */ struct mem_cgroup { struct cgroup_subsys_state css; /* * the counter to account for memory usage */ struct res_counter res; /* * the counter to account for mem+swap usage. */ struct res_counter memsw; /* * Per cgroup active and inactive list, similar to the * per zone LRU lists. */ struct mem_cgroup_lru_info info; /* protect against reclaim related member. */ spinlock_t reclaim_param_lock; /* * While reclaiming in a hierarchy, we cache the last child we * reclaimed from. */ int last_scanned_child; /* * Should the accounting and control be hierarchical, per subtree? */ bool use_hierarchy; atomic_t oom_lock; atomic_t refcnt; unsigned int swappiness; /* OOM-Killer disable */ int oom_kill_disable; /* set when res.limit == memsw.limit */ bool memsw_is_minimum; /* protect arrays of thresholds */ struct mutex thresholds_lock; /* thresholds for memory usage. RCU-protected */ struct mem_cgroup_thresholds thresholds; /* thresholds for mem+swap usage. RCU-protected */ struct mem_cgroup_thresholds memsw_thresholds; /* For oom notifier event fd */ struct list_head oom_notify; /* * Should we move charges of a task when a task is moved into this * mem_cgroup ? And what type of charges should we move ? */ unsigned long move_charge_at_immigrate; /* * percpu counter. */ struct mem_cgroup_stat_cpu *stat; /* * used when a cpu is offlined or other synchronizations * See mem_cgroup_read_stat(). */ struct mem_cgroup_stat_cpu nocpu_base; spinlock_t pcp_counter_lock; }; /* Stuffs for move charges at task migration. */ /* * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a * left-shifted bitmap of these types. */ enum move_type { MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */ MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */ NR_MOVE_TYPE, }; /* "mc" and its members are protected by cgroup_mutex */ static struct move_charge_struct { spinlock_t lock; /* for from, to */ struct mem_cgroup *from; struct mem_cgroup *to; unsigned long precharge; unsigned long moved_charge; unsigned long moved_swap; struct task_struct *moving_task; /* a task moving charges */ wait_queue_head_t waitq; /* a waitq for other context */ } mc = { .lock = __SPIN_LOCK_UNLOCKED(mc.lock), .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq), }; static bool move_anon(void) { return test_bit(MOVE_CHARGE_TYPE_ANON, &mc.to->move_charge_at_immigrate); } static bool move_file(void) { return test_bit(MOVE_CHARGE_TYPE_FILE, &mc.to->move_charge_at_immigrate); } /* * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft * limit reclaim to prevent infinite loops, if they ever occur. */ #define MEM_CGROUP_MAX_RECLAIM_LOOPS (100) #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS (2) enum charge_type { MEM_CGROUP_CHARGE_TYPE_CACHE = 0, MEM_CGROUP_CHARGE_TYPE_MAPPED, MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */ MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */ MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */ MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */ NR_CHARGE_TYPE, }; /* only for here (for easy reading.) */ #define PCGF_CACHE (1UL << PCG_CACHE) #define PCGF_USED (1UL << PCG_USED) #define PCGF_LOCK (1UL << PCG_LOCK) /* Not used, but added here for completeness */ #define PCGF_ACCT (1UL << PCG_ACCT) /* for encoding cft->private value on file */ #define _MEM (0) #define _MEMSWAP (1) #define _OOM_TYPE (2) #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val)) #define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff) #define MEMFILE_ATTR(val) ((val) & 0xffff) /* Used for OOM nofiier */ #define OOM_CONTROL (0) /* * Reclaim flags for mem_cgroup_hierarchical_reclaim */ #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT) #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT) #define MEM_CGROUP_RECLAIM_SOFT_BIT 0x2 #define MEM_CGROUP_RECLAIM_SOFT (1 << MEM_CGROUP_RECLAIM_SOFT_BIT) static void mem_cgroup_get(struct mem_cgroup *mem); static void mem_cgroup_put(struct mem_cgroup *mem); static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem); static void drain_all_stock_async(void); static struct mem_cgroup_per_zone * mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid) { return &mem->info.nodeinfo[nid]->zoneinfo[zid]; } struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem) { return &mem->css; } static struct mem_cgroup_per_zone * page_cgroup_zoneinfo(struct page_cgroup *pc) { struct mem_cgroup *mem = pc->mem_cgroup; int nid = page_cgroup_nid(pc); int zid = page_cgroup_zid(pc); if (!mem) return NULL; return mem_cgroup_zoneinfo(mem, nid, zid); } static struct mem_cgroup_tree_per_zone * soft_limit_tree_node_zone(int nid, int zid) { return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; } static struct mem_cgroup_tree_per_zone * soft_limit_tree_from_page(struct page *page) { int nid = page_to_nid(page); int zid = page_zonenum(page); return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; } static void __mem_cgroup_insert_exceeded(struct mem_cgroup *mem, struct mem_cgroup_per_zone *mz, struct mem_cgroup_tree_per_zone *mctz, unsigned long long new_usage_in_excess) { struct rb_node **p = &mctz->rb_root.rb_node; struct rb_node *parent = NULL; struct mem_cgroup_per_zone *mz_node; if (mz->on_tree) return; mz->usage_in_excess = new_usage_in_excess; if (!mz->usage_in_excess) return; while (*p) { parent = *p; mz_node = rb_entry(parent, struct mem_cgroup_per_zone, tree_node); if (mz->usage_in_excess < mz_node->usage_in_excess) p = &(*p)->rb_left; /* * We can't avoid mem cgroups that are over their soft * limit by the same amount */ else if (mz->usage_in_excess >= mz_node->usage_in_excess) p = &(*p)->rb_right; } rb_link_node(&mz->tree_node, parent, p); rb_insert_color(&mz->tree_node, &mctz->rb_root); mz->on_tree = true; } static void __mem_cgroup_remove_exceeded(struct mem_cgroup *mem, struct mem_cgroup_per_zone *mz, struct mem_cgroup_tree_per_zone *mctz) { if (!mz->on_tree) return; rb_erase(&mz->tree_node, &mctz->rb_root); mz->on_tree = false; } static void mem_cgroup_remove_exceeded(struct mem_cgroup *mem, struct mem_cgroup_per_zone *mz, struct mem_cgroup_tree_per_zone *mctz) { spin_lock(&mctz->lock); __mem_cgroup_remove_exceeded(mem, mz, mctz); spin_unlock(&mctz->lock); } static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page) { unsigned long long excess; struct mem_cgroup_per_zone *mz; struct mem_cgroup_tree_per_zone *mctz; int nid = page_to_nid(page); int zid = page_zonenum(page); mctz = soft_limit_tree_from_page(page); /* * Necessary to update all ancestors when hierarchy is used. * because their event counter is not touched. */ for (; mem; mem = parent_mem_cgroup(mem)) { mz = mem_cgroup_zoneinfo(mem, nid, zid); excess = res_counter_soft_limit_excess(&mem->res); /* * We have to update the tree if mz is on RB-tree or * mem is over its softlimit. */ if (excess || mz->on_tree) { spin_lock(&mctz->lock); /* if on-tree, remove it */ if (mz->on_tree) __mem_cgroup_remove_exceeded(mem, mz, mctz); /* * Insert again. mz->usage_in_excess will be updated. * If excess is 0, no tree ops. */ __mem_cgroup_insert_exceeded(mem, mz, mctz, excess); spin_unlock(&mctz->lock); } } } static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem) { int node, zone; struct mem_cgroup_per_zone *mz; struct mem_cgroup_tree_per_zone *mctz; for_each_node_state(node, N_POSSIBLE) { for (zone = 0; zone < MAX_NR_ZONES; zone++) { mz = mem_cgroup_zoneinfo(mem, node, zone); mctz = soft_limit_tree_node_zone(node, zone); mem_cgroup_remove_exceeded(mem, mz, mctz); } } } static inline unsigned long mem_cgroup_get_excess(struct mem_cgroup *mem) { return res_counter_soft_limit_excess(&mem->res) >> PAGE_SHIFT; } static struct mem_cgroup_per_zone * __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) { struct rb_node *rightmost = NULL; struct mem_cgroup_per_zone *mz; retry: mz = NULL; rightmost = rb_last(&mctz->rb_root); if (!rightmost) goto done; /* Nothing to reclaim from */ mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node); /* * Remove the node now but someone else can add it back, * we will to add it back at the end of reclaim to its correct * position in the tree. */ __mem_cgroup_remove_exceeded(mz->mem, mz, mctz); if (!res_counter_soft_limit_excess(&mz->mem->res) || !css_tryget(&mz->mem->css)) goto retry; done: return mz; } static struct mem_cgroup_per_zone * mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) { struct mem_cgroup_per_zone *mz; spin_lock(&mctz->lock); mz = __mem_cgroup_largest_soft_limit_node(mctz); spin_unlock(&mctz->lock); return mz; } /* * Implementation Note: reading percpu statistics for memcg. * * Both of vmstat[] and percpu_counter has threshold and do periodic * synchronization to implement "quick" read. There are trade-off between * reading cost and precision of value. Then, we may have a chance to implement * a periodic synchronizion of counter in memcg's counter. * * But this _read() function is used for user interface now. The user accounts * memory usage by memory cgroup and he _always_ requires exact value because * he accounts memory. Even if we provide quick-and-fuzzy read, we always * have to visit all online cpus and make sum. So, for now, unnecessary * synchronization is not implemented. (just implemented for cpu hotplug) * * If there are kernel internal actions which can make use of some not-exact * value, and reading all cpu value can be performance bottleneck in some * common workload, threashold and synchonization as vmstat[] should be * implemented. */ static s64 mem_cgroup_read_stat(struct mem_cgroup *mem, enum mem_cgroup_stat_index idx) { int cpu; s64 val = 0; get_online_cpus(); for_each_online_cpu(cpu) val += per_cpu(mem->stat->count[idx], cpu); #ifdef CONFIG_HOTPLUG_CPU spin_lock(&mem->pcp_counter_lock); val += mem->nocpu_base.count[idx]; spin_unlock(&mem->pcp_counter_lock); #endif put_online_cpus(); return val; } static s64 mem_cgroup_local_usage(struct mem_cgroup *mem) { s64 ret; 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_swap_statistics(struct mem_cgroup *mem, bool charge) { int val = (charge) ? 1 : -1; this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_SWAPOUT], val); } static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, bool file, int nr_pages) { preempt_disable(); if (file) __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], nr_pages); else __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], nr_pages); /* pagein of a big page is an event. So, ignore page size */ if (nr_pages > 0) __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGIN_COUNT]); else { __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGOUT_COUNT]); nr_pages = -nr_pages; /* for event */ } __this_cpu_add(mem->stat->count[MEM_CGROUP_EVENTS], nr_pages); preempt_enable(); } static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem, enum lru_list idx) { 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; } static bool __memcg_event_check(struct mem_cgroup *mem, int event_mask_shift) { s64 val; val = this_cpu_read(mem->stat->count[MEM_CGROUP_EVENTS]); return !(val & ((1 << event_mask_shift) - 1)); } /* * Check events in order. * */ static void memcg_check_events(struct mem_cgroup *mem, struct page *page) { /* threshold event is triggered in finer grain than soft limit */ if (unlikely(__memcg_event_check(mem, 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) { return container_of(cgroup_subsys_state(cont, mem_cgroup_subsys_id), struct mem_cgroup, css); } struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) { /* * mm_update_next_owner() may clear mm->owner to NULL * if it races with swapoff, page migration, etc. * So this can be called with p == NULL. */ if (unlikely(!p)) return NULL; return container_of(task_subsys_state(p, mem_cgroup_subsys_id), struct mem_cgroup, css); } static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) { struct mem_cgroup *mem = NULL; if (!mm) return NULL; /* * Because we have no locks, mm->owner's may be being moved to other * cgroup. We use css_tryget() here even if this looks * pessimistic (rather than adding locks here). */ rcu_read_lock(); do { mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); if (unlikely(!mem)) break; } while (!css_tryget(&mem->css)); rcu_read_unlock(); return mem; } /* The caller has to guarantee "mem" exists before calling this */ static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *mem) { struct cgroup_subsys_state *css; int found; if (!mem) /* ROOT cgroup has the smallest ID */ return root_mem_cgroup; /*css_put/get against root is ignored*/ if (!mem->use_hierarchy) { if (css_tryget(&mem->css)) return mem; return NULL; } rcu_read_lock(); /* * searching a memory cgroup which has the smallest ID under given * ROOT cgroup. (ID >= 1) */ css = css_get_next(&mem_cgroup_subsys, 1, &mem->css, &found); if (css && css_tryget(css)) mem = container_of(css, struct mem_cgroup, css); else mem = NULL; rcu_read_unlock(); return mem; } static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter, struct mem_cgroup *root, bool cond) { int nextid = css_id(&iter->css) + 1; int found; int hierarchy_used; struct cgroup_subsys_state *css; hierarchy_used = iter->use_hierarchy; css_put(&iter->css); /* If no ROOT, walk all, ignore hierarchy */ if (!cond || (root && !hierarchy_used)) return NULL; if (!root) root = root_mem_cgroup; do { iter = NULL; rcu_read_lock(); css = css_get_next(&mem_cgroup_subsys, nextid, &root->css, &found); if (css && css_tryget(css)) iter = container_of(css, struct mem_cgroup, css); rcu_read_unlock(); /* If css is NULL, no more cgroups will be found */ nextid = found + 1; } while (css && !iter); return iter; } /* * for_eacn_mem_cgroup_tree() for visiting all cgroup under tree. Please * be careful that "break" loop is not allowed. We have reference count. * Instead of that modify "cond" to be false and "continue" to exit the loop. */ #define for_each_mem_cgroup_tree_cond(iter, root, cond) \ for (iter = mem_cgroup_start_loop(root);\ iter != NULL;\ iter = mem_cgroup_get_next(iter, root, cond)) #define for_each_mem_cgroup_tree(iter, root) \ for_each_mem_cgroup_tree_cond(iter, root, true) #define for_each_mem_cgroup_all(iter) \ for_each_mem_cgroup_tree_cond(iter, NULL, true) static inline bool mem_cgroup_is_root(struct mem_cgroup *mem) { return (mem == root_mem_cgroup); } /* * Following LRU functions are allowed to be used without PCG_LOCK. * Operations are called by routine of global LRU independently from memcg. * What we have to take care of here is validness of pc->mem_cgroup. * * Changes to pc->mem_cgroup happens when * 1. charge * 2. moving account * In typical case, "charge" is done before add-to-lru. Exception is SwapCache. * It is added to LRU before charge. * If PCG_USED bit is not set, page_cgroup is not added to this private LRU. * When moving account, the page is not on LRU. It's isolated. */ void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru) { struct page_cgroup *pc; struct mem_cgroup_per_zone *mz; if (mem_cgroup_disabled()) return; pc = lookup_page_cgroup(page); /* can happen while we handle swapcache. */ if (!TestClearPageCgroupAcctLRU(pc)) return; VM_BUG_ON(!pc->mem_cgroup); /* * We don't check PCG_USED bit. It's cleared when the "page" is finally * removed from global LRU. */ mz = page_cgroup_zoneinfo(pc); /* huge page split is done under lru_lock. so, we have no races. */ MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page); if (mem_cgroup_is_root(pc->mem_cgroup)) return; VM_BUG_ON(list_empty(&pc->lru)); list_del_init(&pc->lru); } void mem_cgroup_del_lru(struct page *page) { mem_cgroup_del_lru_list(page, page_lru(page)); } void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru) { struct mem_cgroup_per_zone *mz; struct page_cgroup *pc; if (mem_cgroup_disabled()) return; pc = lookup_page_cgroup(page); /* unused or root page is not rotated. */ if (!PageCgroupUsed(pc)) return; /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ smp_rmb(); if (mem_cgroup_is_root(pc->mem_cgroup)) return; mz = page_cgroup_zoneinfo(pc); list_move(&pc->lru, &mz->lists[lru]); } void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru) { struct page_cgroup *pc; struct mem_cgroup_per_zone *mz; if (mem_cgroup_disabled()) return; pc = lookup_page_cgroup(page); VM_BUG_ON(PageCgroupAcctLRU(pc)); if (!PageCgroupUsed(pc)) return; /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ smp_rmb(); mz = page_cgroup_zoneinfo(pc); /* huge page split is done under lru_lock. so, we have no races. */ MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page); SetPageCgroupAcctLRU(pc); if (mem_cgroup_is_root(pc->mem_cgroup)) return; list_add(&pc->lru, &mz->lists[lru]); } /* * At handling SwapCache, 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; struct task_struct *p; p = find_lock_task_mm(task); if (!p) return 0; curr = try_get_mem_cgroup_from_mm(p->mm); task_unlock(p); if (!curr) return 0; /* * We should check use_hierarchy of "mem" not "curr". Because checking * use_hierarchy of "curr" here make this function true if hierarchy is * enabled in "curr" and "curr" is a child of "mem" in *cgroup* * hierarchy(even if use_hierarchy is disabled in "mem"). */ if (mem->use_hierarchy) ret = css_is_ancestor(&curr->css, &mem->css); else ret = (curr == mem); css_put(&curr->css); return ret; } static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages) { unsigned long active; unsigned long inactive; unsigned long gb; unsigned long inactive_ratio; inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON); active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON); gb = (inactive + active) >> (30 - PAGE_SHIFT); if (gb) inactive_ratio = int_sqrt(10 * gb); else inactive_ratio = 1; if (present_pages) { present_pages[0] = inactive; present_pages[1] = active; } return inactive_ratio; } int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg) { unsigned long active; unsigned long inactive; unsigned long present_pages[2]; unsigned long inactive_ratio; inactive_ratio = calc_inactive_ratio(memcg, present_pages); inactive = present_pages[0]; active = present_pages[1]; if (inactive * inactive_ratio < active) return 1; return 0; } int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg) { unsigned long active; unsigned long inactive; inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_FILE); active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_FILE); return (active > inactive); } unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg, struct zone *zone, enum lru_list lru) { int nid = zone_to_nid(zone); int zid = zone_idx(zone); struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid); return MEM_CGROUP_ZSTAT(mz, lru); } struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg, struct zone *zone) { int nid = zone_to_nid(zone); int zid = zone_idx(zone); struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid); return &mz->reclaim_stat; } struct zone_reclaim_stat * mem_cgroup_get_reclaim_stat_from_page(struct page *page) { struct page_cgroup *pc; struct mem_cgroup_per_zone *mz; if (mem_cgroup_disabled()) return NULL; pc = lookup_page_cgroup(page); if (!PageCgroupUsed(pc)) return NULL; /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ smp_rmb(); mz = page_cgroup_zoneinfo(pc); 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 = zone_to_nid(z); int zid = zone_idx(z); struct mem_cgroup_per_zone *mz; int lru = LRU_FILE * file + active; int ret; BUG_ON(!mem_cont); mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); src = &mz->lists[lru]; scan = 0; list_for_each_entry_safe_reverse(pc, tmp, src, lru) { if (scan >= nr_to_scan) break; 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 += hpage_nr_pages(page); break; case -EBUSY: /* we don't affect global LRU but rotate in our LRU */ mem_cgroup_rotate_lru_list(page, page_lru(page)); break; default: break; } } *scanned = scan; trace_mm_vmscan_memcg_isolate(0, nr_to_scan, scan, nr_taken, 0, 0, 0, mode); return nr_taken; } #define mem_cgroup_from_res_counter(counter, member) \ container_of(counter, struct mem_cgroup, member) 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; } /** * mem_cgroup_check_margin - check if the memory cgroup allows charging * @mem: memory cgroup to check * @bytes: the number of bytes the caller intends to charge * * Returns a boolean value on whether @mem can be charged @bytes or * whether this would exceed the limit. */ static bool mem_cgroup_check_margin(struct mem_cgroup *mem, unsigned long bytes) { if (!res_counter_check_margin(&mem->res, bytes)) return false; if (do_swap_account && !res_counter_check_margin(&mem->memsw, bytes)) return false; return true; } 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 void mem_cgroup_start_move(struct mem_cgroup *mem) { int cpu; get_online_cpus(); spin_lock(&mem->pcp_counter_lock); for_each_online_cpu(cpu) per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1; mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1; spin_unlock(&mem->pcp_counter_lock); put_online_cpus(); synchronize_rcu(); } static void mem_cgroup_end_move(struct mem_cgroup *mem) { int cpu; if (!mem) return; get_online_cpus(); spin_lock(&mem->pcp_counter_lock); for_each_online_cpu(cpu) per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1; mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1; spin_unlock(&mem->pcp_counter_lock); put_online_cpus(); } /* * 2 routines for checking "mem" is under move_account() or not. * * mem_cgroup_stealed() - checking a cgroup is mc.from or not. This is used * for avoiding race in accounting. If true, * pc->mem_cgroup may be overwritten. * * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or * under hierarchy of moving cgroups. This is for * waiting at hith-memory prressure caused by "move". */ static bool mem_cgroup_stealed(struct mem_cgroup *mem) { VM_BUG_ON(!rcu_read_lock_held()); return this_cpu_read(mem->stat->count[MEM_CGROUP_ON_MOVE]) > 0; } static bool mem_cgroup_under_move(struct mem_cgroup *mem) { struct mem_cgroup *from; struct mem_cgroup *to; bool ret = false; /* * Unlike task_move routines, we access mc.to, mc.from not under * mutual exclusion by cgroup_mutex. Here, we take spinlock instead. */ spin_lock(&mc.lock); from = mc.from; to = mc.to; if (!from) goto unlock; if (from == mem || to == mem || (mem->use_hierarchy && css_is_ancestor(&from->css, &mem->css)) || (mem->use_hierarchy && css_is_ancestor(&to->css, &mem->css))) ret = true; unlock: spin_unlock(&mc.lock); return ret; } static bool mem_cgroup_wait_acct_move(struct mem_cgroup *mem) { if (mc.moving_task && current != mc.moving_task) { if (mem_cgroup_under_move(mem)) { DEFINE_WAIT(wait); prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE); /* moving charge context might have finished. */ if (mc.moving_task) schedule(); finish_wait(&mc.waitq, &wait); return true; } } return false; } /** * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode. * @memcg: The memory cgroup that went over limit * @p: Task that is going to be killed * * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is * enabled */ void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) { struct cgroup *task_cgrp; struct cgroup *mem_cgrp; /* * Need a buffer in BSS, can't rely on allocations. The code relies * on the assumption that OOM is serialized for memory controller. * If this assumption is broken, revisit this code. */ static char memcg_name[PATH_MAX]; int ret; if (!memcg || !p) return; rcu_read_lock(); mem_cgrp = memcg->css.cgroup; task_cgrp = task_cgroup(p, mem_cgroup_subsys_id); ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX); if (ret < 0) { /* * Unfortunately, we are unable to convert to a useful name * But we'll still print out the usage information */ rcu_read_unlock(); goto done; } rcu_read_unlock(); printk(KERN_INFO "Task in %s killed", memcg_name); rcu_read_lock(); ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX); if (ret < 0) { rcu_read_unlock(); goto done; } rcu_read_unlock(); /* * Continues from above, so we don't need an KERN_ level */ printk(KERN_CONT " as a result of limit of %s\n", memcg_name); done: printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n", res_counter_read_u64(&memcg->res, RES_USAGE) >> 10, res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10, res_counter_read_u64(&memcg->res, RES_FAILCNT)); printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, " "failcnt %llu\n", res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10, res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10, res_counter_read_u64(&memcg->memsw, RES_FAILCNT)); } /* * This function returns the number of memcg under hierarchy tree. Returns * 1(self count) if no children. */ static int mem_cgroup_count_children(struct mem_cgroup *mem) { int num = 0; struct mem_cgroup *iter; for_each_mem_cgroup_tree(iter, mem) num++; return num; } /* * Return the memory (and swap, if configured) limit for a memcg. */ u64 mem_cgroup_get_limit(struct mem_cgroup *memcg) { u64 limit; u64 memsw; limit = res_counter_read_u64(&memcg->res, RES_LIMIT); limit += total_swap_pages << PAGE_SHIFT; memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT); /* * If memsw is finite and limits the amount of swap space available * to this memcg, return that limit. */ return min(limit, memsw); } /* * Visit the first child (need not be the first child as per the ordering * of the cgroup list, since we track last_scanned_child) of @mem and use * that to reclaim free pages from. */ static struct mem_cgroup * mem_cgroup_select_victim(struct mem_cgroup *root_mem) { struct mem_cgroup *ret = NULL; struct cgroup_subsys_state *css; int nextid, found; if (!root_mem->use_hierarchy) { css_get(&root_mem->css); ret = root_mem; } while (!ret) { rcu_read_lock(); nextid = root_mem->last_scanned_child + 1; css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css, &found); if (css && css_tryget(css)) ret = container_of(css, struct mem_cgroup, css); rcu_read_unlock(); /* Updates scanning parameter */ 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); 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; } /* * Check OOM-Killer is already running under our hierarchy. * If someone is running, return false. */ static bool mem_cgroup_oom_lock(struct mem_cgroup *mem) { int x, lock_count = 0; struct mem_cgroup *iter; for_each_mem_cgroup_tree(iter, mem) { x = atomic_inc_return(&iter->oom_lock); lock_count = max(x, lock_count); } if (lock_count == 1) return true; return false; } static int mem_cgroup_oom_unlock(struct mem_cgroup *mem) { struct mem_cgroup *iter; /* * When a new child is created while the hierarchy is under oom, * mem_cgroup_oom_lock() may not be called. We have to use * atomic_add_unless() here. */ for_each_mem_cgroup_tree(iter, mem) atomic_add_unless(&iter->oom_lock, -1, 0); return 0; } static DEFINE_MUTEX(memcg_oom_mutex); static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq); struct oom_wait_info { struct mem_cgroup *mem; wait_queue_t wait; }; static int memcg_oom_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *arg) { struct mem_cgroup *wake_mem = (struct mem_cgroup *)arg; struct oom_wait_info *oom_wait_info; oom_wait_info = container_of(wait, struct oom_wait_info, wait); if (oom_wait_info->mem == wake_mem) goto wakeup; /* if no hierarchy, no match */ if (!oom_wait_info->mem->use_hierarchy || !wake_mem->use_hierarchy) return 0; /* * Both of oom_wait_info->mem and wake_mem are stable under us. * Then we can use css_is_ancestor without taking care of RCU. */ if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) && !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css)) return 0; wakeup: return autoremove_wake_function(wait, mode, sync, arg); } static void memcg_wakeup_oom(struct mem_cgroup *mem) { /* for filtering, pass "mem" as argument. */ __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, mem); } static void memcg_oom_recover(struct mem_cgroup *mem) { if (mem && atomic_read(&mem->oom_lock)) memcg_wakeup_oom(mem); } /* * try to call OOM killer. returns false if we should exit memory-reclaim loop. */ bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask) { struct oom_wait_info owait; bool locked, need_to_kill; owait.mem = mem; owait.wait.flags = 0; owait.wait.func = memcg_oom_wake_function; owait.wait.private = current; INIT_LIST_HEAD(&owait.wait.task_list); need_to_kill = true; /* At first, try to OOM lock hierarchy under mem.*/ mutex_lock(&memcg_oom_mutex); locked = mem_cgroup_oom_lock(mem); /* * Even if signal_pending(), we can't quit charge() loop without * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL * under OOM is always welcomed, use TASK_KILLABLE here. */ prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE); if (!locked || mem->oom_kill_disable) need_to_kill = false; if (locked) mem_cgroup_oom_notify(mem); mutex_unlock(&memcg_oom_mutex); if (need_to_kill) { finish_wait(&memcg_oom_waitq, &owait.wait); mem_cgroup_out_of_memory(mem, mask); } else { schedule(); finish_wait(&memcg_oom_waitq, &owait.wait); } mutex_lock(&memcg_oom_mutex); mem_cgroup_oom_unlock(mem); memcg_wakeup_oom(mem); mutex_unlock(&memcg_oom_mutex); if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current)) return false; /* Give chance to dying process */ schedule_timeout(1); return true; } /* * Currently used to update mapped file statistics, but the routine can be * generalized to update other statistics as well. * * Notes: Race condition * * We usually use page_cgroup_lock() for accessing page_cgroup member but * it tends to be costly. But considering some conditions, we doesn't need * to do so _always_. * * Considering "charge", lock_page_cgroup() is not required because all * file-stat operations happen after a page is attached to radix-tree. There * are no race with "charge". * * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even * if there are race with "uncharge". Statistics itself is properly handled * by flags. * * Considering "move", this is an only case we see a race. To make the race * small, we check MEM_CGROUP_ON_MOVE percpu value and detect there are * possibility of race condition. If there is, we take a lock. */ void mem_cgroup_update_page_stat(struct page *page, enum mem_cgroup_page_stat_item idx, int val) { struct mem_cgroup *mem; struct page_cgroup *pc = lookup_page_cgroup(page); bool need_unlock = false; unsigned long uninitialized_var(flags); if (unlikely(!pc)) return; rcu_read_lock(); mem = pc->mem_cgroup; if (unlikely(!mem || !PageCgroupUsed(pc))) goto out; /* pc->mem_cgroup is unstable ? */ if (unlikely(mem_cgroup_stealed(mem)) || PageTransHuge(page)) { /* take a lock against to access pc->mem_cgroup */ move_lock_page_cgroup(pc, &flags); need_unlock = true; mem = pc->mem_cgroup; if (!mem || !PageCgroupUsed(pc)) goto out; } switch (idx) { case MEMCG_NR_FILE_MAPPED: if (val > 0) SetPageCgroupFileMapped(pc); else if (!page_mapped(page)) ClearPageCgroupFileMapped(pc); idx = MEM_CGROUP_STAT_FILE_MAPPED; break; default: BUG(); } this_cpu_add(mem->stat->count[idx], val); out: if (unlikely(need_unlock)) move_unlock_page_cgroup(pc, &flags); rcu_read_unlock(); return; } EXPORT_SYMBOL(mem_cgroup_update_page_stat); /* * size of first charge trial. "32" comes from vmscan.c's magic value. * TODO: maybe necessary to use big numbers in big irons. */ #define CHARGE_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); } /* * This function drains percpu counter value from DEAD cpu and * move it to local cpu. Note that this function can be preempted. */ static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *mem, int cpu) { int i; spin_lock(&mem->pcp_counter_lock); for (i = 0; i < MEM_CGROUP_STAT_DATA; i++) { s64 x = per_cpu(mem->stat->count[i], cpu); per_cpu(mem->stat->count[i], cpu) = 0; mem->nocpu_base.count[i] += x; } /* need to clear ON_MOVE value, works as a kind of lock. */ per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) = 0; spin_unlock(&mem->pcp_counter_lock); } static void synchronize_mem_cgroup_on_move(struct mem_cgroup *mem, int cpu) { int idx = MEM_CGROUP_ON_MOVE; spin_lock(&mem->pcp_counter_lock); per_cpu(mem->stat->count[idx], cpu) = mem->nocpu_base.count[idx]; spin_unlock(&mem->pcp_counter_lock); } static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb, unsigned long action, void *hcpu) { int cpu = (unsigned long)hcpu; struct memcg_stock_pcp *stock; struct mem_cgroup *iter; if ((action == CPU_ONLINE)) { for_each_mem_cgroup_all(iter) synchronize_mem_cgroup_on_move(iter, cpu); return NOTIFY_OK; } if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN) return NOTIFY_OK; for_each_mem_cgroup_all(iter) mem_cgroup_drain_pcp_counter(iter, cpu); stock = &per_cpu(memcg_stock, cpu); drain_stock(stock); return NOTIFY_OK; } /* See __mem_cgroup_try_charge() for details */ enum { CHARGE_OK, /* success */ CHARGE_RETRY, /* need to retry but retry is not bad */ CHARGE_NOMEM, /* we can't do more. return -ENOMEM */ CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */ CHARGE_OOM_DIE, /* the current is killed because of OOM */ }; static int __mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask, int csize, bool oom_check) { struct mem_cgroup *mem_over_limit; struct res_counter *fail_res; unsigned long flags = 0; int ret; ret = res_counter_charge(&mem->res, csize, &fail_res); if (likely(!ret)) { if (!do_swap_account) return CHARGE_OK; ret = res_counter_charge(&mem->memsw, csize, &fail_res); if (likely(!ret)) return CHARGE_OK; res_counter_uncharge(&mem->res, csize); mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw); flags |= MEM_CGROUP_RECLAIM_NOSWAP; } else mem_over_limit = mem_cgroup_from_res_counter(fail_res, res); /* * csize can be either a huge page (HPAGE_SIZE), a batch of * regular pages (CHARGE_SIZE), or a single regular page * (PAGE_SIZE). * * Never reclaim on behalf of optional batching, retry with a * single page instead. */ if (csize == CHARGE_SIZE) return CHARGE_RETRY; if (!(gfp_mask & __GFP_WAIT)) return CHARGE_WOULDBLOCK; ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL, gfp_mask, flags); if (mem_cgroup_check_margin(mem_over_limit, csize)) return CHARGE_RETRY; /* * Even though the limit is exceeded at this point, reclaim * may have been able to free some pages. Retry the charge * before killing the task. * * Only for regular pages, though: huge pages are rather * unlikely to succeed so close to the limit, and we fall back * to regular pages anyway in case of failure. */ if (csize == PAGE_SIZE && ret) return CHARGE_RETRY; /* * At task move, charge accounts can be doubly counted. So, it's * better to wait until the end of task_move if something is going on. */ if (mem_cgroup_wait_acct_move(mem_over_limit)) return CHARGE_RETRY; /* If we don't need to call oom-killer at el, return immediately */ if (!oom_check) return CHARGE_NOMEM; /* check OOM */ if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask)) return CHARGE_OOM_DIE; return CHARGE_RETRY; } /* * Unlike exported interface, "oom" parameter is added. if oom==true, * oom-killer can be invoked. */ static int __mem_cgroup_try_charge(struct mm_struct *mm, gfp_t gfp_mask, struct mem_cgroup **memcg, bool oom, int page_size) { int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; struct mem_cgroup *mem = NULL; int ret; int csize = max(CHARGE_SIZE, (unsigned long) page_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). */ if (!*memcg && !mm) goto bypass; again: if (*memcg) { /* css should be a valid one */ mem = *memcg; VM_BUG_ON(css_is_removed(&mem->css)); if (mem_cgroup_is_root(mem)) goto done; if (page_size == PAGE_SIZE && consume_stock(mem)) goto done; css_get(&mem->css); } else { struct task_struct *p; rcu_read_lock(); p = rcu_dereference(mm->owner); /* * Because we don't have task_lock(), "p" can exit. * In that case, "mem" can point to root or p can be NULL with * race with swapoff. Then, we have small risk of mis-accouning. * But such kind of mis-account by race always happens because * we don't have cgroup_mutex(). It's overkill and we allo that * small race, here. * (*) swapoff at el will charge against mm-struct not against * task-struct. So, mm->owner can be NULL. */ mem = mem_cgroup_from_task(p); if (!mem || mem_cgroup_is_root(mem)) { rcu_read_unlock(); goto done; } if (page_size == PAGE_SIZE && consume_stock(mem)) { /* * It seems dagerous to access memcg without css_get(). * But considering how consume_stok works, it's not * necessary. If consume_stock success, some charges * from this memcg are cached on this cpu. So, we * don't need to call css_get()/css_tryget() before * calling consume_stock(). */ rcu_read_unlock(); goto done; } /* after here, we may be blocked. we need to get refcnt */ if (!css_tryget(&mem->css)) { rcu_read_unlock(); goto again; } rcu_read_unlock(); } do { bool oom_check; /* If killed, bypass charge */ if (fatal_signal_pending(current)) { css_put(&mem->css); goto bypass; } oom_check = false; if (oom && !nr_oom_retries) { oom_check = true; nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; } ret = __mem_cgroup_do_charge(mem, gfp_mask, csize, oom_check); switch (ret) { case CHARGE_OK: break; case CHARGE_RETRY: /* not in OOM situation but retry */ csize = page_size; css_put(&mem->css); mem = NULL; goto again; case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */ css_put(&mem->css); goto nomem; case CHARGE_NOMEM: /* OOM routine works */ if (!oom) { css_put(&mem->css); goto nomem; } /* If oom, we never return -ENOMEM */ nr_oom_retries--; break; case CHARGE_OOM_DIE: /* Killed by OOM Killer */ css_put(&mem->css); goto bypass; } } while (ret != CHARGE_OK); if (csize > page_size) refill_stock(mem, csize - page_size); css_put(&mem->css); done: *memcg = mem; return 0; nomem: *memcg = NULL; return -ENOMEM; bypass: *memcg = NULL; return 0; } /* * Somemtimes we have to undo a charge we got by try_charge(). * This function is for that and do uncharge, put css's refcnt. * gotten by try_charge(). */ static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem, unsigned 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); } } static void mem_cgroup_cancel_charge(struct mem_cgroup *mem, int page_size) { __mem_cgroup_cancel_charge(mem, page_size >> PAGE_SHIFT); } /* * A helper function to get mem_cgroup from ID. must be called under * rcu_read_lock(). The caller must check css_is_removed() or some if * it's concern. (dropping refcnt from swap can be called against removed * memcg.) */ static struct mem_cgroup *mem_cgroup_lookup(unsigned short id) { struct cgroup_subsys_state *css; /* ID 0 is unused ID */ if (!id) return NULL; css = css_lookup(&mem_cgroup_subsys, id); if (!css) return NULL; return container_of(css, struct mem_cgroup, css); } struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) { struct mem_cgroup *mem = NULL; struct page_cgroup *pc; unsigned short id; swp_entry_t ent; VM_BUG_ON(!PageLocked(page)); pc = lookup_page_cgroup(page); lock_page_cgroup(pc); if (PageCgroupUsed(pc)) { mem = pc->mem_cgroup; if (mem && !css_tryget(&mem->css)) mem = NULL; } else if (PageSwapCache(page)) { ent.val = page_private(page); id = lookup_swap_cgroup(ent); rcu_read_lock(); mem = mem_cgroup_lookup(id); if (mem && !css_tryget(&mem->css)) mem = NULL; rcu_read_unlock(); } unlock_page_cgroup(pc); return mem; } static void __mem_cgroup_commit_charge(struct mem_cgroup *mem, struct page_cgroup *pc, enum charge_type ctype, int page_size) { int nr_pages = page_size >> PAGE_SHIFT; /* 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, page_size); return; } /* * we don't need page_cgroup_lock about tail pages, becase they are not * accessed by any other context at this point. */ pc->mem_cgroup = mem; /* * We access a page_cgroup asynchronously without lock_page_cgroup(). * Especially when a page_cgroup is taken from a page, pc->mem_cgroup * is accessed after testing USED bit. To make pc->mem_cgroup visible * before USED bit, we need memory barrier here. * See mem_cgroup_add_lru_list(), etc. */ smp_wmb(); switch (ctype) { case MEM_CGROUP_CHARGE_TYPE_CACHE: case MEM_CGROUP_CHARGE_TYPE_SHMEM: SetPageCgroupCache(pc); SetPageCgroupUsed(pc); break; case MEM_CGROUP_CHARGE_TYPE_MAPPED: ClearPageCgroupCache(pc); SetPageCgroupUsed(pc); break; default: break; } mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), nr_pages); unlock_page_cgroup(pc); /* * "charge_statistics" updated event counter. Then, check it. * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree. * if they exceeds softlimit. */ memcg_check_events(mem, pc->page); } #ifdef CONFIG_TRANSPARENT_HUGEPAGE #define PCGF_NOCOPY_AT_SPLIT ((1 << PCG_LOCK) | (1 << PCG_MOVE_LOCK) |\ (1 << PCG_ACCT_LRU) | (1 << PCG_MIGRATION)) /* * Because tail pages are not marked as "used", set it. We're under * zone->lru_lock, 'splitting on pmd' and compund_lock. */ void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail) { struct page_cgroup *head_pc = lookup_page_cgroup(head); struct page_cgroup *tail_pc = lookup_page_cgroup(tail); unsigned long flags; if (mem_cgroup_disabled()) return; /* * We have no races with charge/uncharge but will have races with * page state accounting. */ move_lock_page_cgroup(head_pc, &flags); tail_pc->mem_cgroup = head_pc->mem_cgroup; smp_wmb(); /* see __commit_charge() */ if (PageCgroupAcctLRU(head_pc)) { enum lru_list lru; struct mem_cgroup_per_zone *mz; /* * LRU flags cannot be copied because we need to add tail *.page to LRU by generic call and our hook will be called. * We hold lru_lock, then, reduce counter directly. */ lru = page_lru(head); mz = page_cgroup_zoneinfo(head_pc); MEM_CGROUP_ZSTAT(mz, lru) -= 1; } tail_pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT; move_unlock_page_cgroup(head_pc, &flags); } #endif /** * __mem_cgroup_move_account - move account of the page * @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, int charge_size) { int nr_pages = charge_size >> PAGE_SHIFT; VM_BUG_ON(from == to); VM_BUG_ON(PageLRU(pc->page)); VM_BUG_ON(!page_is_cgroup_locked(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, PageCgroupCache(pc), -nr_pages); if (uncharge) /* This is not "cancel", but cancel_charge does all we need. */ mem_cgroup_cancel_charge(from, charge_size); /* caller should have done css_get */ pc->mem_cgroup = to; mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages); /* * We charges against "to" which may not have any tasks. Then, "to" * can be under rmdir(). But in current implementation, caller of * this function is just force_empty() and move charge, so it's * 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 charge_size) { int ret = -EINVAL; unsigned long flags; /* * The page is isolated from LRU. So, collapse function * will not handle this page. But page splitting can happen. * Do this check under compound_page_lock(). The caller should * hold it. */ if ((charge_size > PAGE_SIZE) && !PageTransHuge(pc->page)) return -EBUSY; lock_page_cgroup(pc); if (PageCgroupUsed(pc) && pc->mem_cgroup == from) { move_lock_page_cgroup(pc, &flags); __mem_cgroup_move_account(pc, from, to, uncharge, charge_size); move_unlock_page_cgroup(pc, &flags); 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 page_size = PAGE_SIZE; unsigned long flags; int ret; /* Is ROOT ? */ if (!pcg) return -EINVAL; ret = -EBUSY; if (!get_page_unless_zero(page)) goto out; if (isolate_lru_page(page)) goto put; if (PageTransHuge(page)) page_size = HPAGE_SIZE; parent = mem_cgroup_from_cont(pcg); ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false, page_size); if (ret || !parent) goto put_back; if (page_size > PAGE_SIZE) flags = compound_lock_irqsave(page); ret = mem_cgroup_move_account(pc, child, parent, true, page_size); if (ret) mem_cgroup_cancel_charge(parent, page_size); if (page_size > PAGE_SIZE) compound_unlock_irqrestore(page, flags); put_back: putback_lru_page(page); put: put_page(page); out: return ret; } /* * Charge the memory controller for page usage. * Return * 0 if the charge was successful * < 0 if the cgroup is over its limit */ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, gfp_t gfp_mask, enum charge_type ctype) { struct mem_cgroup *mem = NULL; int page_size = PAGE_SIZE; struct page_cgroup *pc; bool oom = true; int ret; if (PageTransHuge(page)) { page_size <<= compound_order(page); VM_BUG_ON(!PageTransHuge(page)); /* * Never OOM-kill a process for a huge page. The * fault handler will fall back to regular pages. */ oom = false; } pc = lookup_page_cgroup(page); /* can happen at boot */ if (unlikely(!pc)) return 0; prefetchw(pc); ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, oom, page_size); if (ret || !mem) return ret; __mem_cgroup_commit_charge(mem, pc, ctype, page_size); return 0; } int mem_cgroup_newpage_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) { if (mem_cgroup_disabled()) return 0; /* * If already mapped, we don't have to account. * If page cache, page->mapping has address_space. * But page->mapping may have out-of-use anon_vma pointer, * detecit it by PageAnon() check. newly-mapped-anon's page->mapping * is NULL. */ if (page_mapped(page) || (page->mapping && !PageAnon(page))) return 0; if (unlikely(!mm)) mm = &init_mm; return mem_cgroup_charge_common(page, mm, gfp_mask, MEM_CGROUP_CHARGE_TYPE_MAPPED); } static void __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, enum charge_type ctype); int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) { int ret; if (mem_cgroup_disabled()) return 0; if (PageCompound(page)) return 0; /* * Corner case handling. This is called from add_to_page_cache() * in usual. But some FS (shmem) precharges this page before calling it * and call add_to_page_cache() with GFP_NOWAIT. * * For GFP_NOWAIT case, the page may be pre-charged before calling * add_to_page_cache(). (See shmem.c) check it here and avoid to call * charge twice. (It works but has to pay a bit larger cost.) * And when the page is SwapCache, it should take swap information * into account. This is under lock_page() now. */ if (!(gfp_mask & __GFP_WAIT)) { struct page_cgroup *pc; pc = lookup_page_cgroup(page); if (!pc) return 0; lock_page_cgroup(pc); if (PageCgroupUsed(pc)) { unlock_page_cgroup(pc); return 0; } unlock_page_cgroup(pc); } if (unlikely(!mm)) mm = &init_mm; if (page_is_file_cache(page)) return mem_cgroup_charge_common(page, mm, gfp_mask, MEM_CGROUP_CHARGE_TYPE_CACHE); /* shmem */ if (PageSwapCache(page)) { struct mem_cgroup *mem = NULL; ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem); if (!ret) __mem_cgroup_commit_charge_swapin(page, mem, MEM_CGROUP_CHARGE_TYPE_SHMEM); } else ret = mem_cgroup_charge_common(page, mm, gfp_mask, MEM_CGROUP_CHARGE_TYPE_SHMEM); return ret; } /* * While swap-in, try_charge -> commit or cancel, the page is locked. * And when try_charge() successfully returns, one refcnt to memcg without * struct page_cgroup is acquired. This refcnt will be consumed by * "commit()" or removed by "cancel()" */ int mem_cgroup_try_charge_swapin(struct mm_struct *mm, struct page *page, gfp_t mask, struct mem_cgroup **ptr) { struct mem_cgroup *mem; int ret; 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, PAGE_SIZE); css_put(&mem->css); return ret; charge_cur_mm: if (unlikely(!mm)) mm = &init_mm; return __mem_cgroup_try_charge(mm, mask, ptr, true, PAGE_SIZE); } 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, PAGE_SIZE); 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, PAGE_SIZE); } static void __do_uncharge(struct mem_cgroup *mem, const enum charge_type ctype, int page_size) { struct memcg_batch_info *batch = NULL; bool uncharge_memsw = true; /* If swapout, usage of swap doesn't decrease */ if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) uncharge_memsw = false; batch = ¤t->memcg_batch; /* * In usual, we do css_get() when we remember memcg pointer. * But in this case, we keep res->usage until end of a series of * uncharges. Then, it's ok to ignore memcg's refcnt. */ if (!batch->memcg) batch->memcg = mem; /* * do_batch > 0 when unmapping pages or inode invalidate/truncate. * In those cases, all pages freed continously can be expected to be in * the same cgroup and we have chance to coalesce uncharges. * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE) * because we want to do uncharge as soon as possible. */ if (!batch->do_batch || test_thread_flag(TIF_MEMDIE)) goto direct_uncharge; if (page_size != PAGE_SIZE) goto direct_uncharge; /* * In typical case, batch->memcg == mem. This means we can * merge a series of uncharges to an uncharge of res_counter. * If not, we uncharge res_counter ony by one. */ if (batch->memcg != mem) goto direct_uncharge; /* remember freed charge and uncharge it later */ batch->bytes += PAGE_SIZE; if (uncharge_memsw) batch->memsw_bytes += PAGE_SIZE; return; direct_uncharge: res_counter_uncharge(&mem->res, page_size); if (uncharge_memsw) res_counter_uncharge(&mem->memsw, page_size); if (unlikely(batch->memcg != mem)) memcg_oom_recover(mem); return; } /* * uncharge if !page_mapped(page) */ static struct mem_cgroup * __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype) { int count; struct page_cgroup *pc; struct mem_cgroup *mem = NULL; int page_size = PAGE_SIZE; if (mem_cgroup_disabled()) return NULL; if (PageSwapCache(page)) return NULL; if (PageTransHuge(page)) { page_size <<= compound_order(page); VM_BUG_ON(!PageTransHuge(page)); } count = page_size >> PAGE_SHIFT; /* * Check if our page_cgroup is valid */ pc = lookup_page_cgroup(page); if (unlikely(!pc || !PageCgroupUsed(pc))) return NULL; lock_page_cgroup(pc); mem = pc->mem_cgroup; if (!PageCgroupUsed(pc)) goto unlock_out; switch (ctype) { case MEM_CGROUP_CHARGE_TYPE_MAPPED: case MEM_CGROUP_CHARGE_TYPE_DROP: /* See mem_cgroup_prepare_migration() */ if (page_mapped(page) || PageCgroupMigration(pc)) goto unlock_out; break; case MEM_CGROUP_CHARGE_TYPE_SWAPOUT: if (!PageAnon(page)) { /* Shared memory */ if (page->mapping && !page_is_file_cache(page)) goto unlock_out; } else if (page_mapped(page)) /* Anon */ goto unlock_out; break; default: break; } mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), -count); ClearPageCgroupUsed(pc); /* * pc->mem_cgroup is not cleared here. It will be accessed when it's * freed from LRU. This is safe because uncharged page is expected not * to be reused (freed soon). Exception is SwapCache, it's handled by * special functions. */ unlock_page_cgroup(pc); /* * even after unlock, we have mem->res.usage here and this memcg * will never be freed. */ memcg_check_events(mem, page); if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) { mem_cgroup_swap_statistics(mem, true); mem_cgroup_get(mem); } if (!mem_cgroup_is_root(mem)) __do_uncharge(mem, ctype, page_size); return mem; unlock_out: unlock_page_cgroup(pc); return NULL; } void mem_cgroup_uncharge_page(struct page *page) { /* early check. */ if (page_mapped(page)) return; if (page->mapping && !PageAnon(page)) return; __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED); } void mem_cgroup_uncharge_cache_page(struct page *page) { VM_BUG_ON(page_mapped(page)); VM_BUG_ON(page->mapping); __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE); } /* * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate. * In that cases, pages are freed continuously and we can expect pages * are in the same memcg. All these calls itself limits the number of * pages freed at once, then uncharge_start/end() is called properly. * This may be called prural(2) times in a context, */ void mem_cgroup_uncharge_start(void) { current->memcg_batch.do_batch++; /* We can do nest. */ if (current->memcg_batch.do_batch == 1) { current->memcg_batch.memcg = NULL; current->memcg_batch.bytes = 0; current->memcg_batch.memsw_bytes = 0; } } void mem_cgroup_uncharge_end(void) { struct memcg_batch_info *batch = ¤t->memcg_batch; if (!batch->do_batch) return; batch->do_batch--; if (batch->do_batch) /* If stacked, do nothing. */ return; if (!batch->memcg) return; /* * This "batch->memcg" is valid without any css_get/put etc... * bacause we hide charges behind us. */ if (batch->bytes) res_counter_uncharge(&batch->memcg->res, batch->bytes); if (batch->memsw_bytes) res_counter_uncharge(&batch->memcg->memsw, batch->memsw_bytes); memcg_oom_recover(batch->memcg); /* forget this pointer (for sanity check) */ batch->memcg = NULL; } #ifdef CONFIG_SWAP /* * called after __delete_from_swap_cache() and drop "page" account. * memcg information is recorded to swap_cgroup of "ent" */ void mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) { struct mem_cgroup *memcg; int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT; if (!swapout) /* this was a swap cache but the swap is unused ! */ ctype = MEM_CGROUP_CHARGE_TYPE_DROP; memcg = __mem_cgroup_uncharge_common(page, ctype); /* * record memcg information, if swapout && memcg != NULL, * mem_cgroup_get() was called in uncharge(). */ if (do_swap_account && swapout && memcg) swap_cgroup_record(ent, css_id(&memcg->css)); } #endif #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP /* * called from swap_entry_free(). remove record in swap_cgroup and * uncharge "memsw" account. */ void mem_cgroup_uncharge_swap(swp_entry_t ent) { struct mem_cgroup *memcg; unsigned short id; if (!do_swap_account) return; id = swap_cgroup_record(ent, 0); rcu_read_lock(); memcg = mem_cgroup_lookup(id); if (memcg) { /* * We uncharge this because swap is freed. * This memcg can be obsolete one. We avoid calling css_tryget */ if (!mem_cgroup_is_root(memcg)) res_counter_uncharge(&memcg->memsw, PAGE_SIZE); mem_cgroup_swap_statistics(memcg, false); mem_cgroup_put(memcg); } rcu_read_unlock(); } /** * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record. * @entry: swap entry to be moved * @from: mem_cgroup which the entry is moved from * @to: mem_cgroup which the entry is moved to * @need_fixup: whether we should fixup res_counters and refcounts. * * It succeeds only when the swap_cgroup's record for this entry is the same * as the mem_cgroup's id of @from. * * Returns 0 on success, -EINVAL on failure. * * The caller must have charged to @to, IOW, called res_counter_charge() about * both res and memsw, and called css_get(). */ static int mem_cgroup_move_swap_account(swp_entry_t entry, struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup) { unsigned short old_id, new_id; old_id = css_id(&from->css); new_id = css_id(&to->css); if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { mem_cgroup_swap_statistics(from, false); mem_cgroup_swap_statistics(to, true); /* * This function is only called from task migration context now. * It postpones res_counter and refcount handling till the end * of task migration(mem_cgroup_clear_mc()) for performance * improvement. But we cannot postpone mem_cgroup_get(to) * because if the process that has been moved to @to does * swap-in, the refcount of @to might be decreased to 0. */ mem_cgroup_get(to); if (need_fixup) { if (!mem_cgroup_is_root(from)) res_counter_uncharge(&from->memsw, PAGE_SIZE); mem_cgroup_put(from); /* * we charged both to->res and to->memsw, so we should * uncharge to->res. */ if (!mem_cgroup_is_root(to)) res_counter_uncharge(&to->res, PAGE_SIZE); } return 0; } return -EINVAL; } #else static inline int mem_cgroup_move_swap_account(swp_entry_t entry, struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup) { return -EINVAL; } #endif /* * Before starting migration, account PAGE_SIZE to mem_cgroup that the old * page belongs to. */ int mem_cgroup_prepare_migration(struct page *page, struct page *newpage, struct mem_cgroup **ptr) { struct page_cgroup *pc; struct mem_cgroup *mem = NULL; enum charge_type ctype; int ret = 0; VM_BUG_ON(PageTransHuge(page)); if (mem_cgroup_disabled()) return 0; pc = lookup_page_cgroup(page); lock_page_cgroup(pc); if (PageCgroupUsed(pc)) { mem = pc->mem_cgroup; css_get(&mem->css); /* * At migrating an anonymous page, its mapcount goes down * to 0 and uncharge() will be called. But, even if it's fully * unmapped, migration may fail and this page has to be * charged again. We set MIGRATION flag here and delay uncharge * until end_migration() is called * * Corner Case Thinking * A) * When the old page was mapped as Anon and it's unmap-and-freed * while migration was ongoing. * If unmap finds the old page, uncharge() of it will be delayed * until end_migration(). If unmap finds a new page, it's * uncharged when it make mapcount to be 1->0. If unmap code * finds swap_migration_entry, the new page will not be mapped * and end_migration() will find it(mapcount==0). * * B) * When the old page was mapped but migraion fails, the kernel * remaps it. A charge for it is kept by MIGRATION flag even * if mapcount goes down to 0. We can do remap successfully * without charging it again. * * C) * The "old" page is under lock_page() until the end of * migration, so, the old page itself will not be swapped-out. * If the new page is swapped out before end_migraton, our * hook to usual swap-out path will catch the event. */ if (PageAnon(page)) SetPageCgroupMigration(pc); } unlock_page_cgroup(pc); /* * If the page is not charged at this point, * we return here. */ if (!mem) return 0; *ptr = mem; ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, ptr, false, PAGE_SIZE); css_put(&mem->css);/* drop extra refcnt */ if (ret || *ptr == NULL) { if (PageAnon(page)) { lock_page_cgroup(pc); ClearPageCgroupMigration(pc); unlock_page_cgroup(pc); /* * The old page may be fully unmapped while we kept it. */ mem_cgroup_uncharge_page(page); } return -ENOMEM; } /* * We charge new page before it's used/mapped. So, even if unlock_page() * is called before end_migration, we can catch all events on this new * page. In the case new page is migrated but not remapped, new page's * mapcount will be finally 0 and we call uncharge in end_migration(). */ pc = lookup_page_cgroup(newpage); if (PageAnon(page)) ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED; else if (page_is_file_cache(page)) ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; else ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM; __mem_cgroup_commit_charge(mem, pc, ctype, PAGE_SIZE); return ret; } /* remove redundant charge if migration failed*/ void mem_cgroup_end_migration(struct mem_cgroup *mem, struct page *oldpage, struct page *newpage, bool migration_ok) { struct page *used, *unused; struct page_cgroup *pc; if (!mem) return; /* blocks rmdir() */ cgroup_exclude_rmdir(&mem->css); if (!migration_ok) { used = oldpage; unused = newpage; } else { used = newpage; unused = oldpage; } /* * We disallowed uncharge of pages under migration because mapcount * of the page goes down to zero, temporarly. * Clear the flag and check the page should be charged. */ pc = lookup_page_cgroup(oldpage); lock_page_cgroup(pc); ClearPageCgroupMigration(pc); unlock_page_cgroup(pc); __mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE); /* * If a page is a file cache, radix-tree replacement is very atomic * and we can skip this check. When it was an Anon page, its mapcount * goes down to 0. But because we added MIGRATION flage, it's not * uncharged yet. There are several case but page->mapcount check * and USED bit check in mem_cgroup_uncharge_page() will do enough * check. (see prepare_charge() also) */ if (PageAnon(used)) mem_cgroup_uncharge_page(used); /* * At migration, we may charge account against cgroup which has no * tasks. * So, rmdir()->pre_destroy() can be called while we do this charge. * In that case, we need to call pre_destroy() again. check it here. */ cgroup_release_and_wakeup_rmdir(&mem->css); } /* * A call to try to shrink memory usage on charge failure at shmem's swapin. * Calling hierarchical_reclaim is not enough because we should update * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM. * Moreover considering hierarchy, we should reclaim from the mem_over_limit, * not from the memcg which this page would be charged to. * try_charge_swapin does all of these works properly. */ int mem_cgroup_shmem_charge_fallback(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) { struct mem_cgroup *mem = NULL; int ret; if (mem_cgroup_disabled()) return 0; ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem); if (!ret) mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */ return ret; } static DEFINE_MUTEX(set_limit_mutex); static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, unsigned long long val) { int retry_count; u64 memswlimit, memlimit; int ret = 0; int children = mem_cgroup_count_children(memcg); u64 curusage, oldusage; int enlarge; /* * For keeping hierarchical_reclaim simple, how long we should retry * is depends on callers. We set our retry-count to be function * of # of children which we should visit in this loop. */ retry_count = MEM_CGROUP_RECLAIM_RETRIES * children; oldusage = res_counter_read_u64(&memcg->res, RES_USAGE); enlarge = 0; while (retry_count) { if (signal_pending(current)) { ret = -EINTR; break; } /* * Rather than hide all in some function, I do this in * open coded manner. You see what this really does. * We have to guarantee mem->res.limit < mem->memsw.limit. */ mutex_lock(&set_limit_mutex); memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); if (memswlimit < val) { ret = -EINVAL; mutex_unlock(&set_limit_mutex); break; } memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); if (memlimit < val) enlarge = 1; ret = res_counter_set_limit(&memcg->res, val); if (!ret) { if (memswlimit == val) memcg->memsw_is_minimum = true; else memcg->memsw_is_minimum = false; } mutex_unlock(&set_limit_mutex); if (!ret) break; mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL, MEM_CGROUP_RECLAIM_SHRINK); curusage = res_counter_read_u64(&memcg->res, RES_USAGE); /* Usage is reduced ? */ if (curusage >= oldusage) retry_count--; else oldusage = curusage; } if (!ret && enlarge) memcg_oom_recover(memcg); return ret; } static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, unsigned long long val) { int retry_count; u64 memlimit, memswlimit, oldusage, curusage; int children = mem_cgroup_count_children(memcg); int ret = -EBUSY; int enlarge = 0; /* see mem_cgroup_resize_res_limit */ retry_count = children * MEM_CGROUP_RECLAIM_RETRIES; oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); while (retry_count) { if (signal_pending(current)) { ret = -EINTR; break; } /* * Rather than hide all in some function, I do this in * open coded manner. You see what this really does. * We have to guarantee mem->res.limit < mem->memsw.limit. */ mutex_lock(&set_limit_mutex); memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); if (memlimit > val) { ret = -EINVAL; mutex_unlock(&set_limit_mutex); break; } memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); if (memswlimit < val) enlarge = 1; ret = res_counter_set_limit(&memcg->memsw, val); if (!ret) { if (memlimit == val) memcg->memsw_is_minimum = true; else memcg->memsw_is_minimum = false; } mutex_unlock(&set_limit_mutex); if (!ret) break; mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL, MEM_CGROUP_RECLAIM_NOSWAP | MEM_CGROUP_RECLAIM_SHRINK); curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); /* Usage is reduced ? */ if (curusage >= oldusage) retry_count--; else oldusage = curusage; } if (!ret && enlarge) memcg_oom_recover(memcg); return ret; } unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, gfp_t gfp_mask) { 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(zone_to_nid(zone), zone_idx(zone)); /* * This loop can run a while, specially if mem_cgroup's continuously * keep exceeding their soft limit and putting the system under * pressure */ do { if (next_mz) mz = next_mz; else mz = mem_cgroup_largest_soft_limit_node(mctz); if (!mz) break; 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; mem_cgroup_start_move(mem); for_each_node_state(node, N_HIGH_MEMORY) { for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) { enum lru_list l; for_each_lru(l) { ret = mem_cgroup_force_empty_list(mem, node, zid, l); if (ret) break; } } if (ret) break; } mem_cgroup_end_move(mem); memcg_oom_recover(mem); /* it seems parent cgroup doesn't have enough mem */ if (ret == -ENOMEM) goto try_to_free; cond_resched(); /* "ret" should also be checked to ensure all lists are empty. */ } while (mem->res.usage > 0 || ret); out: css_put(&mem->css); return ret; try_to_free: /* returns EBUSY if there is a task or if we come here twice. */ if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) { ret = -EBUSY; goto out; } /* we call try-to-free pages for make this cgroup empty */ lru_add_drain_all(); /* try to free all pages in this cgroup */ shrink = 1; while (nr_retries && mem->res.usage > 0) { int progress; if (signal_pending(current)) { ret = -EINTR; goto out; } progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL, false, get_swappiness(mem)); if (!progress) { nr_retries--; /* maybe some writeback is necessary */ congestion_wait(BLK_RW_ASYNC, HZ/10); } } lru_add_drain(); /* try move_account...there may be some *locked* pages. */ goto move_account; } int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event) { return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true); } static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft) { return mem_cgroup_from_cont(cont)->use_hierarchy; } static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft, u64 val) { int retval = 0; struct mem_cgroup *mem = mem_cgroup_from_cont(cont); struct cgroup *parent = cont->parent; struct mem_cgroup *parent_mem = NULL; if (parent) parent_mem = mem_cgroup_from_cont(parent); cgroup_lock(); /* * If parent's use_hierarchy is set, we can't make any modifications * in the child subtrees. If it is unset, then the change can * occur, provided the current cgroup has no children. * * For the root cgroup, parent_mem is NULL, we allow value to be * set if there are no children. */ if ((!parent_mem || !parent_mem->use_hierarchy) && (val == 1 || val == 0)) { if (list_empty(&cont->children)) mem->use_hierarchy = val; else retval = -EBUSY; } else retval = -EINVAL; cgroup_unlock(); return retval; } static u64 mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem, enum mem_cgroup_stat_index idx) { struct mem_cgroup *iter; s64 val = 0; /* each per cpu's value can be minus.Then, use s64 */ for_each_mem_cgroup_tree(iter, mem) val += mem_cgroup_read_stat(iter, idx); if (val < 0) /* race ? */ val = 0; return val; } static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap) { u64 val; if (!mem_cgroup_is_root(mem)) { if (!swap) return res_counter_read_u64(&mem->res, RES_USAGE); else return res_counter_read_u64(&mem->memsw, RES_USAGE); } val = mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_CACHE); val += mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_RSS); if (swap) val += mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_SWAPOUT); return val << PAGE_SHIFT; } static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft) { struct mem_cgroup *mem = mem_cgroup_from_cont(cont); u64 val; int type, name; type = MEMFILE_TYPE(cft->private); name = MEMFILE_ATTR(cft->private); switch (type) { case _MEM: if (name == RES_USAGE) val = mem_cgroup_usage(mem, false); else val = res_counter_read_u64(&mem->res, name); break; case _MEMSWAP: if (name == RES_USAGE) val = mem_cgroup_usage(mem, true); else val = res_counter_read_u64(&mem->memsw, name); break; default: BUG(); break; } return val; } /* * The user of this function is... * RES_LIMIT. */ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft, const char *buffer) { struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); int type, name; unsigned long long val; int ret; type = MEMFILE_TYPE(cft->private); name = MEMFILE_ATTR(cft->private); switch (name) { case RES_LIMIT: if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */ ret = -EINVAL; break; } /* This function does all necessary parse...reuse it */ ret = res_counter_memparse_write_strategy(buffer, &val); if (ret) break; if (type == _MEM) ret = mem_cgroup_resize_limit(memcg, val); else ret = mem_cgroup_resize_memsw_limit(memcg, val); break; case RES_SOFT_LIMIT: ret = res_counter_memparse_write_strategy(buffer, &val); if (ret) break; /* * For memsw, soft limits are hard to implement in terms * of semantics, for now, we support soft limits for * control without swap */ if (type == _MEM) ret = res_counter_set_soft_limit(&memcg->res, val); else ret = -EINVAL; break; default: ret = -EINVAL; /* should be BUG() ? */ break; } return ret; } static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg, unsigned long long *mem_limit, unsigned long long *memsw_limit) { struct cgroup *cgroup; unsigned long long min_limit, min_memsw_limit, tmp; min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT); min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); cgroup = memcg->css.cgroup; if (!memcg->use_hierarchy) goto out; while (cgroup->parent) { cgroup = cgroup->parent; memcg = mem_cgroup_from_cont(cgroup); if (!memcg->use_hierarchy) break; tmp = res_counter_read_u64(&memcg->res, RES_LIMIT); min_limit = min(min_limit, tmp); tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT); min_memsw_limit = min(min_memsw_limit, tmp); } out: *mem_limit = min_limit; *memsw_limit = min_memsw_limit; return; } static int mem_cgroup_reset(struct cgroup *cont, unsigned int event) { struct mem_cgroup *mem; int type, name; mem = mem_cgroup_from_cont(cont); type = MEMFILE_TYPE(event); name = MEMFILE_ATTR(event); switch (name) { case RES_MAX_USAGE: if (type == _MEM) res_counter_reset_max(&mem->res); else res_counter_reset_max(&mem->memsw); break; case RES_FAILCNT: if (type == _MEM) res_counter_reset_failcnt(&mem->res); else res_counter_reset_failcnt(&mem->memsw); break; } return 0; } static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp, struct cftype *cft) { return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate; } #ifdef CONFIG_MMU static int mem_cgroup_move_charge_write(struct cgroup *cgrp, struct cftype *cft, u64 val) { struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); if (val >= (1 << NR_MOVE_TYPE)) return -EINVAL; /* * We check this value several times in both in can_attach() and * attach(), so we need cgroup lock to prevent this value from being * inconsistent. */ cgroup_lock(); mem->move_charge_at_immigrate = val; cgroup_unlock(); return 0; } #else static int mem_cgroup_move_charge_write(struct cgroup *cgrp, struct cftype *cft, u64 val) { return -ENOSYS; } #endif /* For read statistics */ enum { MCS_CACHE, MCS_RSS, MCS_FILE_MAPPED, MCS_PGPGIN, MCS_PGPGOUT, MCS_SWAP, MCS_INACTIVE_ANON, MCS_ACTIVE_ANON, MCS_INACTIVE_FILE, MCS_ACTIVE_FILE, MCS_UNEVICTABLE, NR_MCS_STAT, }; struct mcs_total_stat { s64 stat[NR_MCS_STAT]; }; struct { char *local_name; char *total_name; } memcg_stat_strings[NR_MCS_STAT] = { {"cache", "total_cache"}, {"rss", "total_rss"}, {"mapped_file", "total_mapped_file"}, {"pgpgin", "total_pgpgin"}, {"pgpgout", "total_pgpgout"}, {"swap", "total_swap"}, {"inactive_anon", "total_inactive_anon"}, {"active_anon", "total_active_anon"}, {"inactive_file", "total_inactive_file"}, {"active_file", "total_active_file"}, {"unevictable", "total_unevictable"} }; static void mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s) { s64 val; /* per cpu stat */ val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE); s->stat[MCS_CACHE] += val * PAGE_SIZE; val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS); s->stat[MCS_RSS] += val * PAGE_SIZE; val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED); s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE; val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGIN_COUNT); s->stat[MCS_PGPGIN] += val; val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGOUT_COUNT); s->stat[MCS_PGPGOUT] += val; if (do_swap_account) { val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT); s->stat[MCS_SWAP] += val * PAGE_SIZE; } /* per zone stat */ val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON); s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE; val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON); s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE; val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE); s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE; val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE); s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE; val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE); s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE; } static void mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s) { struct mem_cgroup *iter; for_each_mem_cgroup_tree(iter, mem) mem_cgroup_get_local_stat(iter, s); } static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft, struct cgroup_map_cb *cb) { struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont); struct mcs_total_stat mystat; int i; memset(&mystat, 0, sizeof(mystat)); mem_cgroup_get_local_stat(mem_cont, &mystat); for (i = 0; i < NR_MCS_STAT; i++) { if (i == MCS_SWAP && !do_swap_account) continue; cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]); } /* Hierarchical information */ { unsigned long long limit, memsw_limit; memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit); cb->fill(cb, "hierarchical_memory_limit", limit); if (do_swap_account) cb->fill(cb, "hierarchical_memsw_limit", memsw_limit); } memset(&mystat, 0, sizeof(mystat)); mem_cgroup_get_total_stat(mem_cont, &mystat); for (i = 0; i < NR_MCS_STAT; i++) { if (i == MCS_SWAP && !do_swap_account) continue; cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]); } #ifdef CONFIG_DEBUG_VM cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL)); { int nid, zid; struct mem_cgroup_per_zone *mz; unsigned long recent_rotated[2] = {0, 0}; unsigned long recent_scanned[2] = {0, 0}; for_each_online_node(nid) for (zid = 0; zid < MAX_NR_ZONES; zid++) { mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); recent_rotated[0] += mz->reclaim_stat.recent_rotated[0]; recent_rotated[1] += mz->reclaim_stat.recent_rotated[1]; recent_scanned[0] += mz->reclaim_stat.recent_scanned[0]; recent_scanned[1] += mz->reclaim_stat.recent_scanned[1]; } cb->fill(cb, "recent_rotated_anon", recent_rotated[0]); cb->fill(cb, "recent_rotated_file", recent_rotated[1]); cb->fill(cb, "recent_scanned_anon", recent_scanned[0]); cb->fill(cb, "recent_scanned_file", recent_scanned[1]); } #endif return 0; } static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft) { struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); return get_swappiness(memcg); } static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft, u64 val) { struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); struct mem_cgroup *parent; if (val > 100) return -EINVAL; if (cgrp->parent == NULL) return -EINVAL; parent = mem_cgroup_from_cont(cgrp->parent); cgroup_lock(); /* If under hierarchy, only empty-root can set this value */ if ((parent->use_hierarchy) || (memcg->use_hierarchy && !list_empty(&cgrp->children))) { cgroup_unlock(); return -EINVAL; } spin_lock(&memcg->reclaim_param_lock); memcg->swappiness = val; spin_unlock(&memcg->reclaim_param_lock); cgroup_unlock(); return 0; } static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap) { struct mem_cgroup_threshold_ary *t; u64 usage; int i; rcu_read_lock(); if (!swap) t = rcu_dereference(memcg->thresholds.primary); else t = rcu_dereference(memcg->memsw_thresholds.primary); if (!t) goto unlock; usage = mem_cgroup_usage(memcg, swap); /* * current_threshold points to threshold just below usage. * If it's not true, a threshold was crossed after last * call of __mem_cgroup_threshold(). */ i = t->current_threshold; /* * Iterate backward over array of thresholds starting from * current_threshold and check if a threshold is crossed. * If none of thresholds below usage is crossed, we read * only one element of the array here. */ for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--) eventfd_signal(t->entries[i].eventfd, 1); /* i = current_threshold + 1 */ i++; /* * Iterate forward over array of thresholds starting from * current_threshold+1 and check if a threshold is crossed. * If none of thresholds above usage is crossed, we read * only one element of the array here. */ for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++) eventfd_signal(t->entries[i].eventfd, 1); /* Update current_threshold */ t->current_threshold = i - 1; unlock: rcu_read_unlock(); } static void mem_cgroup_threshold(struct mem_cgroup *memcg) { while (memcg) { __mem_cgroup_threshold(memcg, false); if (do_swap_account) __mem_cgroup_threshold(memcg, true); memcg = parent_mem_cgroup(memcg); } } static int compare_thresholds(const void *a, const void *b) { const struct mem_cgroup_threshold *_a = a; const struct mem_cgroup_threshold *_b = b; return _a->threshold - _b->threshold; } static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem) { struct mem_cgroup_eventfd_list *ev; list_for_each_entry(ev, &mem->oom_notify, list) eventfd_signal(ev->eventfd, 1); return 0; } static void mem_cgroup_oom_notify(struct mem_cgroup *mem) { struct mem_cgroup *iter; for_each_mem_cgroup_tree(iter, mem) mem_cgroup_oom_notify_cb(iter); } static int mem_cgroup_usage_register_event(struct cgroup *cgrp, struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) { struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); struct mem_cgroup_thresholds *thresholds; struct mem_cgroup_threshold_ary *new; int type = MEMFILE_TYPE(cft->private); u64 threshold, usage; int i, size, ret; ret = res_counter_memparse_write_strategy(args, &threshold); if (ret) return ret; mutex_lock(&memcg->thresholds_lock); if (type == _MEM) thresholds = &memcg->thresholds; else if (type == _MEMSWAP) thresholds = &memcg->memsw_thresholds; else BUG(); usage = mem_cgroup_usage(memcg, type == _MEMSWAP); /* Check if a threshold crossed before adding a new one */ if (thresholds->primary) __mem_cgroup_threshold(memcg, type == _MEMSWAP); size = thresholds->primary ? thresholds->primary->size + 1 : 1; /* Allocate memory for new array of thresholds */ new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold), GFP_KERNEL); if (!new) { ret = -ENOMEM; goto unlock; } new->size = size; /* Copy thresholds (if any) to new array */ if (thresholds->primary) { memcpy(new->entries, thresholds->primary->entries, (size - 1) * sizeof(struct mem_cgroup_threshold)); } /* Add new threshold */ new->entries[size - 1].eventfd = eventfd; new->entries[size - 1].threshold = threshold; /* Sort thresholds. Registering of new threshold isn't time-critical */ sort(new->entries, size, sizeof(struct mem_cgroup_threshold), compare_thresholds, NULL); /* Find current threshold */ new->current_threshold = -1; for (i = 0; i < size; i++) { if (new->entries[i].threshold < usage) { /* * new->current_threshold will not be used until * rcu_assign_pointer(), so it's safe to increment * it here. */ ++new->current_threshold; } } /* Free old spare buffer and save old primary buffer as spare */ kfree(thresholds->spare); thresholds->spare = thresholds->primary; rcu_assign_pointer(thresholds->primary, new); /* To be sure that nobody uses thresholds */ synchronize_rcu(); unlock: mutex_unlock(&memcg->thresholds_lock); return ret; } static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp, struct cftype *cft, struct eventfd_ctx *eventfd) { struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); struct mem_cgroup_thresholds *thresholds; struct mem_cgroup_threshold_ary *new; int type = MEMFILE_TYPE(cft->private); u64 usage; int i, j, size; mutex_lock(&memcg->thresholds_lock); if (type == _MEM) thresholds = &memcg->thresholds; else if (type == _MEMSWAP) thresholds = &memcg->memsw_thresholds; else BUG(); /* * Something went wrong if we trying to unregister a threshold * if we don't have thresholds */ BUG_ON(!thresholds); usage = mem_cgroup_usage(memcg, type == _MEMSWAP); /* Check if a threshold crossed before removing */ __mem_cgroup_threshold(memcg, type == _MEMSWAP); /* Calculate new number of threshold */ size = 0; for (i = 0; i < thresholds->primary->size; i++) { if (thresholds->primary->entries[i].eventfd != eventfd) size++; } new = thresholds->spare; /* Set thresholds array to NULL if we don't have thresholds */ if (!size) { kfree(new); new = NULL; goto swap_buffers; } new->size = size; /* Copy thresholds and find current threshold */ new->current_threshold = -1; for (i = 0, j = 0; i < thresholds->primary->size; i++) { if (thresholds->primary->entries[i].eventfd == eventfd) continue; new->entries[j] = thresholds->primary->entries[i]; if (new->entries[j].threshold < usage) { /* * new->current_threshold will not be used * until rcu_assign_pointer(), so it's safe to increment * it here. */ ++new->current_threshold; } j++; } swap_buffers: /* Swap primary and spare array */ thresholds->spare = thresholds->primary; rcu_assign_pointer(thresholds->primary, new); /* To be sure that nobody uses thresholds */ synchronize_rcu(); mutex_unlock(&memcg->thresholds_lock); } static int mem_cgroup_oom_register_event(struct cgroup *cgrp, struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) { struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); struct mem_cgroup_eventfd_list *event; int type = MEMFILE_TYPE(cft->private); BUG_ON(type != _OOM_TYPE); event = kmalloc(sizeof(*event), GFP_KERNEL); if (!event) return -ENOMEM; mutex_lock(&memcg_oom_mutex); event->eventfd = eventfd; list_add(&event->list, &memcg->oom_notify); /* already in OOM ? */ if (atomic_read(&memcg->oom_lock)) eventfd_signal(eventfd, 1); mutex_unlock(&memcg_oom_mutex); return 0; } static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp, struct cftype *cft, struct eventfd_ctx *eventfd) { struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); struct mem_cgroup_eventfd_list *ev, *tmp; int type = MEMFILE_TYPE(cft->private); BUG_ON(type != _OOM_TYPE); mutex_lock(&memcg_oom_mutex); list_for_each_entry_safe(ev, tmp, &mem->oom_notify, list) { if (ev->eventfd == eventfd) { list_del(&ev->list); kfree(ev); } } mutex_unlock(&memcg_oom_mutex); } static int mem_cgroup_oom_control_read(struct cgroup *cgrp, struct cftype *cft, struct cgroup_map_cb *cb) { struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); cb->fill(cb, "oom_kill_disable", mem->oom_kill_disable); if (atomic_read(&mem->oom_lock)) cb->fill(cb, "under_oom", 1); else cb->fill(cb, "under_oom", 0); return 0; } static int mem_cgroup_oom_control_write(struct cgroup *cgrp, struct cftype *cft, u64 val) { struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); struct mem_cgroup *parent; /* cannot set to root cgroup and only 0 and 1 are allowed */ if (!cgrp->parent || !((val == 0) || (val == 1))) return -EINVAL; parent = mem_cgroup_from_cont(cgrp->parent); cgroup_lock(); /* oom-kill-disable is a flag for subhierarchy. */ if ((parent->use_hierarchy) || (mem->use_hierarchy && !list_empty(&cgrp->children))) { cgroup_unlock(); return -EINVAL; } mem->oom_kill_disable = val; if (!val) memcg_oom_recover(mem); cgroup_unlock(); return 0; } static struct cftype mem_cgroup_files[] = { { .name = "usage_in_bytes", .private = MEMFILE_PRIVATE(_MEM, RES_USAGE), .read_u64 = mem_cgroup_read, .register_event = mem_cgroup_usage_register_event, .unregister_event = mem_cgroup_usage_unregister_event, }, { .name = "max_usage_in_bytes", .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE), .trigger = mem_cgroup_reset, .read_u64 = mem_cgroup_read, }, { .name = "limit_in_bytes", .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT), .write_string = mem_cgroup_write, .read_u64 = mem_cgroup_read, }, { .name = "soft_limit_in_bytes", .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT), .write_string = mem_cgroup_write, .read_u64 = mem_cgroup_read, }, { .name = "failcnt", .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT), .trigger = mem_cgroup_reset, .read_u64 = mem_cgroup_read, }, { .name = "stat", .read_map = mem_control_stat_show, }, { .name = "force_empty", .trigger = mem_cgroup_force_empty_write, }, { .name = "use_hierarchy", .write_u64 = mem_cgroup_hierarchy_write, .read_u64 = mem_cgroup_hierarchy_read, }, { .name = "swappiness", .read_u64 = mem_cgroup_swappiness_read, .write_u64 = mem_cgroup_swappiness_write, }, { .name = "move_charge_at_immigrate", .read_u64 = mem_cgroup_move_charge_read, .write_u64 = mem_cgroup_move_charge_write, }, { .name = "oom_control", .read_map = mem_cgroup_oom_control_read, .write_u64 = mem_cgroup_oom_control_write, .register_event = mem_cgroup_oom_register_event, .unregister_event = mem_cgroup_oom_unregister_event, .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL), }, }; #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP static struct cftype memsw_cgroup_files[] = { { .name = "memsw.usage_in_bytes", .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), .read_u64 = mem_cgroup_read, .register_event = mem_cgroup_usage_register_event, .unregister_event = mem_cgroup_usage_unregister_event, }, { .name = "memsw.max_usage_in_bytes", .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE), .trigger = mem_cgroup_reset, .read_u64 = mem_cgroup_read, }, { .name = "memsw.limit_in_bytes", .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT), .write_string = mem_cgroup_write, .read_u64 = mem_cgroup_read, }, { .name = "memsw.failcnt", .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT), .trigger = mem_cgroup_reset, .read_u64 = mem_cgroup_read, }, }; static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) { if (!do_swap_account) return 0; return cgroup_add_files(cont, ss, memsw_cgroup_files, ARRAY_SIZE(memsw_cgroup_files)); }; #else static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) { return 0; } #endif static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) { struct mem_cgroup_per_node *pn; struct mem_cgroup_per_zone *mz; enum lru_list l; int zone, tmp = node; /* * This routine is called against possible nodes. * But it's BUG to call kmalloc() against offline node. * * TODO: this routine can waste much memory for nodes which will * never be onlined. It's better to use memory hotplug callback * function. */ if (!node_state(node, N_NORMAL_MEMORY)) tmp = -1; pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp); if (!pn) return 1; mem->info.nodeinfo[node] = pn; for (zone = 0; zone < MAX_NR_ZONES; zone++) { mz = &pn->zoneinfo[zone]; for_each_lru(l) INIT_LIST_HEAD(&mz->lists[l]); mz->usage_in_excess = 0; mz->on_tree = false; mz->mem = mem; } return 0; } static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) { kfree(mem->info.nodeinfo[node]); } static struct mem_cgroup *mem_cgroup_alloc(void) { struct mem_cgroup *mem; int size = sizeof(struct mem_cgroup); /* Can be very big if MAX_NUMNODES is very big */ if (size < PAGE_SIZE) mem = kzalloc(size, GFP_KERNEL); else mem = vzalloc(size); if (!mem) return NULL; mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu); if (!mem->stat) goto out_free; spin_lock_init(&mem->pcp_counter_lock); return mem; out_free: if (size < PAGE_SIZE) kfree(mem); else vfree(mem); return NULL; } /* * At destroying mem_cgroup, references from swap_cgroup can remain. * (scanning all at force_empty is too costly...) * * Instead of clearing all references at force_empty, we remember * the number of reference from swap_cgroup and free mem_cgroup when * it goes down to 0. * * Removal of cgroup itself succeeds regardless of refs from swap. */ static void __mem_cgroup_free(struct mem_cgroup *mem) { int node; mem_cgroup_remove_from_trees(mem); free_css_id(&mem_cgroup_subsys, &mem->css); for_each_node_state(node, N_POSSIBLE) free_mem_cgroup_per_zone_info(mem, node); free_percpu(mem->stat); if (sizeof(struct mem_cgroup) < PAGE_SIZE) kfree(mem); else vfree(mem); } static void mem_cgroup_get(struct mem_cgroup *mem) { atomic_inc(&mem->refcnt); } static void __mem_cgroup_put(struct mem_cgroup *mem, int count) { if (atomic_sub_and_test(count, &mem->refcnt)) { struct mem_cgroup *parent = parent_mem_cgroup(mem); __mem_cgroup_free(mem); if (parent) mem_cgroup_put(parent); } } static void mem_cgroup_put(struct mem_cgroup *mem) { __mem_cgroup_put(mem, 1); } /* * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled. */ static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem) { if (!mem->res.parent) return NULL; return mem_cgroup_from_res_counter(mem->res.parent, res); } #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP static void __init enable_swap_cgroup(void) { if (!mem_cgroup_disabled() && really_do_swap_account) do_swap_account = 1; } #else static void __init enable_swap_cgroup(void) { } #endif static int mem_cgroup_soft_limit_tree_init(void) { struct mem_cgroup_tree_per_node *rtpn; struct mem_cgroup_tree_per_zone *rtpz; int tmp, node, zone; for_each_node_state(node, N_POSSIBLE) { tmp = node; if (!node_state(node, N_NORMAL_MEMORY)) tmp = -1; rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp); if (!rtpn) return 1; soft_limit_tree.rb_tree_per_node[node] = rtpn; for (zone = 0; zone < MAX_NR_ZONES; zone++) { rtpz = &rtpn->rb_tree_per_zone[zone]; rtpz->rb_root = RB_ROOT; spin_lock_init(&rtpz->lock); } } return 0; } static struct cgroup_subsys_state * __ref mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) { struct mem_cgroup *mem, *parent; long error = -ENOMEM; int node; mem = mem_cgroup_alloc(); if (!mem) return ERR_PTR(error); for_each_node_state(node, N_POSSIBLE) if (alloc_mem_cgroup_per_zone_info(mem, node)) goto free_out; /* root ? */ if (cont->parent == NULL) { int cpu; enable_swap_cgroup(); parent = NULL; 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_cpu_hotplug_callback, 0); } else { parent = mem_cgroup_from_cont(cont->parent); mem->use_hierarchy = parent->use_hierarchy; mem->oom_kill_disable = parent->oom_kill_disable; } if (parent && parent->use_hierarchy) { res_counter_init(&mem->res, &parent->res); res_counter_init(&mem->memsw, &parent->memsw); /* * We increment refcnt of the parent to ensure that we can * safely access it on res_counter_charge/uncharge. * This refcnt will be decremented when freeing this * mem_cgroup(see mem_cgroup_put). */ mem_cgroup_get(parent); } else { res_counter_init(&mem->res, NULL); res_counter_init(&mem->memsw, NULL); } mem->last_scanned_child = 0; spin_lock_init(&mem->reclaim_param_lock); INIT_LIST_HEAD(&mem->oom_notify); if (parent) mem->swappiness = get_swappiness(parent); atomic_set(&mem->refcnt, 1); mem->move_charge_at_immigrate = 0; mutex_init(&mem->thresholds_lock); return &mem->css; free_out: __mem_cgroup_free(mem); root_mem_cgroup = NULL; return ERR_PTR(error); } static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss, struct cgroup *cont) { struct mem_cgroup *mem = mem_cgroup_from_cont(cont); return mem_cgroup_force_empty(mem, false); } static void mem_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cont) { struct mem_cgroup *mem = mem_cgroup_from_cont(cont); mem_cgroup_put(mem); } static int mem_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont) { int ret; ret = cgroup_add_files(cont, ss, mem_cgroup_files, ARRAY_SIZE(mem_cgroup_files)); if (!ret) ret = register_memsw_files(cont, ss); return ret; } #ifdef CONFIG_MMU /* Handlers for move charge at task migration. */ #define PRECHARGE_COUNT_AT_ONCE 256 static int mem_cgroup_do_precharge(unsigned long count) { int ret = 0; int batch_count = PRECHARGE_COUNT_AT_ONCE; struct mem_cgroup *mem = mc.to; if (mem_cgroup_is_root(mem)) { mc.precharge += count; /* we don't need css_get for root */ return ret; } /* try to charge at once */ if (count > 1) { struct res_counter *dummy; /* * "mem" cannot be under rmdir() because we've already checked * by cgroup_lock_live_cgroup() that it is not removed and we * are still under the same cgroup_mutex. So we can postpone * css_get(). */ if (res_counter_charge(&mem->res, PAGE_SIZE * count, &dummy)) goto one_by_one; if (do_swap_account && res_counter_charge(&mem->memsw, PAGE_SIZE * count, &dummy)) { res_counter_uncharge(&mem->res, PAGE_SIZE * count); goto one_by_one; } mc.precharge += count; return ret; } one_by_one: /* fall back to one by one charge */ while (count--) { if (signal_pending(current)) { ret = -EINTR; break; } if (!batch_count--) { batch_count = PRECHARGE_COUNT_AT_ONCE; cond_resched(); } ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false, PAGE_SIZE); if (ret || !mem) /* mem_cgroup_clear_mc() will do uncharge later */ return -ENOMEM; mc.precharge++; } return ret; } /** * is_target_pte_for_mc - check a pte whether it is valid for move charge * @vma: the vma the pte to be checked belongs * @addr: the address corresponding to the pte to be checked * @ptent: the pte to be checked * @target: the pointer the target page or swap ent will be stored(can be NULL) * * Returns * 0(MC_TARGET_NONE): if the pte is not a target for move charge. * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for * move charge. if @target is not NULL, the page is stored in target->page * with extra refcnt got(Callers should handle it). * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a * target for charge migration. if @target is not NULL, the entry is stored * in target->ent. * * Called with pte lock held. */ union mc_target { struct page *page; swp_entry_t ent; }; enum mc_target_type { MC_TARGET_NONE, /* not used */ MC_TARGET_PAGE, MC_TARGET_SWAP, }; static struct page *mc_handle_present_pte(struct vm_area_struct *vma, unsigned long addr, pte_t ptent) { struct page *page = vm_normal_page(vma, addr, ptent); if (!page || !page_mapped(page)) return NULL; if (PageAnon(page)) { /* we don't move shared anon */ if (!move_anon() || page_mapcount(page) > 2) return NULL; } else if (!move_file()) /* we ignore mapcount for file pages */ return NULL; if (!get_page_unless_zero(page)) return NULL; return page; } static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, unsigned long addr, pte_t ptent, swp_entry_t *entry) { int usage_count; struct page *page = NULL; swp_entry_t ent = pte_to_swp_entry(ptent); if (!move_anon() || non_swap_entry(ent)) return NULL; usage_count = mem_cgroup_count_swap_user(ent, &page); if (usage_count > 1) { /* we don't move shared anon */ if (page) put_page(page); return NULL; } if (do_swap_account) entry->val = ent.val; return page; } static struct page *mc_handle_file_pte(struct vm_area_struct *vma, unsigned long addr, pte_t ptent, swp_entry_t *entry) { struct page *page = NULL; struct inode *inode; struct address_space *mapping; pgoff_t pgoff; if (!vma->vm_file) /* anonymous vma */ return NULL; if (!move_file()) return NULL; inode = vma->vm_file->f_path.dentry->d_inode; mapping = vma->vm_file->f_mapping; if (pte_none(ptent)) pgoff = linear_page_index(vma, addr); else /* pte_file(ptent) is true */ pgoff = pte_to_pgoff(ptent); /* page is moved even if it's not RSS of this task(page-faulted). */ if (!mapping_cap_swap_backed(mapping)) { /* normal file */ page = find_get_page(mapping, pgoff); } else { /* shmem/tmpfs file. we should take account of swap too. */ swp_entry_t ent; mem_cgroup_get_shmem_target(inode, pgoff, &page, &ent); if (do_swap_account) entry->val = ent.val; } return page; } static int is_target_pte_for_mc(struct vm_area_struct *vma, unsigned long addr, pte_t ptent, union mc_target *target) { struct page *page = NULL; struct page_cgroup *pc; int ret = 0; swp_entry_t ent = { .val = 0 }; if (pte_present(ptent)) page = mc_handle_present_pte(vma, addr, ptent); else if (is_swap_pte(ptent)) page = mc_handle_swap_pte(vma, addr, ptent, &ent); else if (pte_none(ptent) || pte_file(ptent)) page = mc_handle_file_pte(vma, addr, ptent, &ent); if (!page && !ent.val) return 0; if (page) { pc = lookup_page_cgroup(page); /* * Do only loose check w/o page_cgroup lock. * mem_cgroup_move_account() checks the pc is valid or not under * the lock. */ if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) { ret = MC_TARGET_PAGE; if (target) target->page = page; } if (!ret || !target) put_page(page); } /* There is a swap entry and a page doesn't exist or isn't charged */ if (ent.val && !ret && css_id(&mc.from->css) == lookup_swap_cgroup(ent)) { ret = MC_TARGET_SWAP; if (target) target->ent = ent; } return ret; } static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, struct mm_walk *walk) { struct vm_area_struct *vma = walk->private; pte_t *pte; spinlock_t *ptl; VM_BUG_ON(pmd_trans_huge(*pmd)); pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); for (; addr != end; pte++, addr += PAGE_SIZE) if (is_target_pte_for_mc(vma, addr, *pte, NULL)) mc.precharge++; /* increment precharge temporarily */ pte_unmap_unlock(pte - 1, ptl); cond_resched(); return 0; } static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm) { unsigned long precharge; struct vm_area_struct *vma; down_read(&mm->mmap_sem); for (vma = mm->mmap; vma; vma = vma->vm_next) { struct mm_walk mem_cgroup_count_precharge_walk = { .pmd_entry = mem_cgroup_count_precharge_pte_range, .mm = mm, .private = vma, }; if (is_vm_hugetlb_page(vma)) continue; walk_page_range(vma->vm_start, vma->vm_end, &mem_cgroup_count_precharge_walk); } up_read(&mm->mmap_sem); precharge = mc.precharge; mc.precharge = 0; return precharge; } static int mem_cgroup_precharge_mc(struct mm_struct *mm) { unsigned long precharge = mem_cgroup_count_precharge(mm); VM_BUG_ON(mc.moving_task); mc.moving_task = current; return mem_cgroup_do_precharge(precharge); } /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */ static void __mem_cgroup_clear_mc(void) { struct mem_cgroup *from = mc.from; struct mem_cgroup *to = mc.to; /* we must uncharge all the leftover precharges from mc.to */ if (mc.precharge) { __mem_cgroup_cancel_charge(mc.to, mc.precharge); mc.precharge = 0; } /* * we didn't uncharge from mc.from at mem_cgroup_move_account(), so * we must uncharge here. */ if (mc.moved_charge) { __mem_cgroup_cancel_charge(mc.from, mc.moved_charge); mc.moved_charge = 0; } /* we must fixup refcnts and charges */ if (mc.moved_swap) { /* uncharge swap account from the old cgroup */ if (!mem_cgroup_is_root(mc.from)) res_counter_uncharge(&mc.from->memsw, PAGE_SIZE * mc.moved_swap); __mem_cgroup_put(mc.from, mc.moved_swap); if (!mem_cgroup_is_root(mc.to)) { /* * we charged both to->res and to->memsw, so we should * uncharge to->res. */ res_counter_uncharge(&mc.to->res, PAGE_SIZE * mc.moved_swap); } /* we've already done mem_cgroup_get(mc.to) */ mc.moved_swap = 0; } memcg_oom_recover(from); memcg_oom_recover(to); wake_up_all(&mc.waitq); } static void mem_cgroup_clear_mc(void) { struct mem_cgroup *from = mc.from; /* * we must clear moving_task before waking up waiters at the end of * task migration. */ mc.moving_task = NULL; __mem_cgroup_clear_mc(); spin_lock(&mc.lock); mc.from = NULL; mc.to = NULL; spin_unlock(&mc.lock); mem_cgroup_end_move(from); } static int mem_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgroup, struct task_struct *p, 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); mem_cgroup_start_move(from); spin_lock(&mc.lock); mc.from = from; mc.to = mem; spin_unlock(&mc.lock); /* We set mc.moving_task later */ ret = mem_cgroup_precharge_mc(mm); if (ret) mem_cgroup_clear_mc(); } mmput(mm); } return ret; } static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss, struct cgroup *cgroup, struct task_struct *p, 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: VM_BUG_ON(pmd_trans_huge(*pmd)); 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, PAGE_SIZE)) { mc.precharge--; /* we uncharge from mc.from later. */ mc.moved_charge++; } putback_lru_page(page); put: /* is_target_pte_for_mc() gets the page */ put_page(page); break; case MC_TARGET_SWAP: ent = target.ent; if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to, false)) { mc.precharge--; /* we fixup refcnts and charges later. */ mc.moved_swap++; } break; default: break; } } pte_unmap_unlock(pte - 1, ptl); cond_resched(); if (addr != end) { /* * We have consumed all precharges we got in can_attach(). * We try charge one by one, but don't do any additional * charges to mc.to if we have failed in charge once in attach() * phase. */ ret = mem_cgroup_do_precharge(1); if (!ret) goto retry; } return ret; } static void mem_cgroup_move_charge(struct mm_struct *mm) { struct vm_area_struct *vma; lru_add_drain_all(); retry: if (unlikely(!down_read_trylock(&mm->mmap_sem))) { /* * Someone who are holding the mmap_sem might be waiting in * waitq. So we cancel all extra charges, wake up all waiters, * and retry. Because we cancel precharges, we might not be able * to move enough charges, but moving charge is a best-effort * feature anyway, so it wouldn't be a big problem. */ __mem_cgroup_clear_mc(); cond_resched(); goto retry; } for (vma = mm->mmap; vma; vma = vma->vm_next) { int ret; struct mm_walk mem_cgroup_move_charge_walk = { .pmd_entry = mem_cgroup_move_charge_pte_range, .mm = mm, .private = vma, }; if (is_vm_hugetlb_page(vma)) continue; ret = walk_page_range(vma->vm_start, vma->vm_end, &mem_cgroup_move_charge_walk); if (ret) /* * means we have consumed all precharges and failed in * doing additional charge. Just abandon here. */ break; } up_read(&mm->mmap_sem); } static void mem_cgroup_move_task(struct cgroup_subsys *ss, struct cgroup *cont, struct cgroup *old_cont, struct task_struct *p, 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", .subsys_id = mem_cgroup_subsys_id, .create = mem_cgroup_create, .pre_destroy = mem_cgroup_pre_destroy, .destroy = mem_cgroup_destroy, .populate = mem_cgroup_populate, .can_attach = mem_cgroup_can_attach, .cancel_attach = mem_cgroup_cancel_attach, .attach = mem_cgroup_move_task, .early_init = 0, .use_id = 1, }; #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP static int __init enable_swap_account(char *s) { /* consider enabled if no parameter or 1 is given */ if (!(*s) || !strcmp(s, "=1")) really_do_swap_account = 1; else if (!strcmp(s, "=0")) really_do_swap_account = 0; return 1; } __setup("swapaccount", enable_swap_account); static int __init disable_swap_account(char *s) { printk_once("noswapaccount is deprecated and will be removed in 2.6.40. Use swapaccount=0 instead\n"); enable_swap_account("=0"); return 1; } __setup("noswapaccount", disable_swap_account); #endif