| /* memcontrol.c - Memory Controller |
| * |
| * Copyright IBM Corporation, 2007 |
| * Author Balbir Singh <balbir@linux.vnet.ibm.com> |
| * |
| * Copyright 2007 OpenVZ SWsoft Inc |
| * Author: Pavel Emelianov <xemul@openvz.org> |
| * |
| * Memory thresholds |
| * Copyright (C) 2009 Nokia Corporation |
| * Author: Kirill A. Shutemov |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| */ |
| |
| #include <linux/res_counter.h> |
| #include <linux/memcontrol.h> |
| #include <linux/cgroup.h> |
| #include <linux/mm.h> |
| #include <linux/hugetlb.h> |
| #include <linux/pagemap.h> |
| #include <linux/smp.h> |
| #include <linux/page-flags.h> |
| #include <linux/backing-dev.h> |
| #include <linux/bit_spinlock.h> |
| #include <linux/rcupdate.h> |
| #include <linux/limits.h> |
| #include <linux/export.h> |
| #include <linux/mutex.h> |
| #include <linux/rbtree.h> |
| #include <linux/slab.h> |
| #include <linux/swap.h> |
| #include <linux/swapops.h> |
| #include <linux/spinlock.h> |
| #include <linux/eventfd.h> |
| #include <linux/sort.h> |
| #include <linux/fs.h> |
| #include <linux/seq_file.h> |
| #include <linux/vmalloc.h> |
| #include <linux/mm_inline.h> |
| #include <linux/page_cgroup.h> |
| #include <linux/cpu.h> |
| #include <linux/oom.h> |
| #include "internal.h" |
| #include <net/sock.h> |
| #include <net/tcp_memcontrol.h> |
| |
| #include <asm/uaccess.h> |
| |
| #include <trace/events/vmscan.h> |
| |
| struct cgroup_subsys mem_cgroup_subsys __read_mostly; |
| #define MEM_CGROUP_RECLAIM_RETRIES 5 |
| struct mem_cgroup *root_mem_cgroup __read_mostly; |
| |
| #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP |
| /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */ |
| int do_swap_account __read_mostly; |
| |
| /* for remember boot option*/ |
| #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED |
| static int really_do_swap_account __initdata = 1; |
| #else |
| static int really_do_swap_account __initdata = 0; |
| #endif |
| |
| #else |
| #define do_swap_account (0) |
| #endif |
| |
| |
| /* |
| * Statistics for memory cgroup. |
| */ |
| enum mem_cgroup_stat_index { |
| /* |
| * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss. |
| */ |
| MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */ |
| MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */ |
| MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */ |
| MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */ |
| MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */ |
| MEM_CGROUP_ON_MOVE, /* someone is moving account between groups */ |
| MEM_CGROUP_STAT_NSTATS, |
| }; |
| |
| enum mem_cgroup_events_index { |
| MEM_CGROUP_EVENTS_PGPGIN, /* # of pages paged in */ |
| MEM_CGROUP_EVENTS_PGPGOUT, /* # of pages paged out */ |
| MEM_CGROUP_EVENTS_COUNT, /* # of pages paged in/out */ |
| MEM_CGROUP_EVENTS_PGFAULT, /* # of page-faults */ |
| MEM_CGROUP_EVENTS_PGMAJFAULT, /* # of major page-faults */ |
| MEM_CGROUP_EVENTS_NSTATS, |
| }; |
| /* |
| * Per memcg event counter is incremented at every pagein/pageout. With THP, |
| * it will be incremated by the number of pages. This counter is used for |
| * for trigger some periodic events. This is straightforward and better |
| * than using jiffies etc. to handle periodic memcg event. |
| */ |
| enum mem_cgroup_events_target { |
| MEM_CGROUP_TARGET_THRESH, |
| MEM_CGROUP_TARGET_SOFTLIMIT, |
| MEM_CGROUP_TARGET_NUMAINFO, |
| MEM_CGROUP_NTARGETS, |
| }; |
| #define THRESHOLDS_EVENTS_TARGET (128) |
| #define SOFTLIMIT_EVENTS_TARGET (1024) |
| #define NUMAINFO_EVENTS_TARGET (1024) |
| |
| struct mem_cgroup_stat_cpu { |
| long count[MEM_CGROUP_STAT_NSTATS]; |
| unsigned long events[MEM_CGROUP_EVENTS_NSTATS]; |
| unsigned long targets[MEM_CGROUP_NTARGETS]; |
| }; |
| |
| struct mem_cgroup_reclaim_iter { |
| /* css_id of the last scanned hierarchy member */ |
| int position; |
| /* scan generation, increased every round-trip */ |
| unsigned int generation; |
| }; |
| |
| /* |
| * per-zone information in memory controller. |
| */ |
| struct mem_cgroup_per_zone { |
| struct lruvec lruvec; |
| unsigned long count[NR_LRU_LISTS]; |
| |
| struct mem_cgroup_reclaim_iter reclaim_iter[DEF_PRIORITY + 1]; |
| |
| 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 *memcg); |
| static void mem_cgroup_oom_notify(struct mem_cgroup *memcg); |
| |
| /* |
| * The memory controller data structure. The memory controller controls both |
| * page cache and RSS per cgroup. We would eventually like to provide |
| * statistics based on the statistics developed by Rik Van Riel for clock-pro, |
| * to help the administrator determine what knobs to tune. |
| * |
| * TODO: Add a water mark for the memory controller. Reclaim will begin when |
| * we hit the water mark. May be even add a low water mark, such that |
| * no reclaim occurs from a cgroup at it's low water mark, this is |
| * a feature that will be implemented much later in the future. |
| */ |
| struct mem_cgroup { |
| struct cgroup_subsys_state css; |
| /* |
| * the counter to account for memory usage |
| */ |
| struct res_counter res; |
| |
| union { |
| /* |
| * the counter to account for mem+swap usage. |
| */ |
| struct res_counter memsw; |
| |
| /* |
| * rcu_freeing is used only when freeing struct mem_cgroup, |
| * so put it into a union to avoid wasting more memory. |
| * It must be disjoint from the css field. It could be |
| * in a union with the res field, but res plays a much |
| * larger part in mem_cgroup life than memsw, and might |
| * be of interest, even at time of free, when debugging. |
| * So share rcu_head with the less interesting memsw. |
| */ |
| struct rcu_head rcu_freeing; |
| /* |
| * But when using vfree(), that cannot be done at |
| * interrupt time, so we must then queue the work. |
| */ |
| struct work_struct work_freeing; |
| }; |
| |
| /* |
| * Per cgroup active and inactive list, similar to the |
| * per zone LRU lists. |
| */ |
| struct mem_cgroup_lru_info info; |
| int last_scanned_node; |
| #if MAX_NUMNODES > 1 |
| nodemask_t scan_nodes; |
| atomic_t numainfo_events; |
| atomic_t numainfo_updating; |
| #endif |
| /* |
| * Should the accounting and control be hierarchical, per subtree? |
| */ |
| bool use_hierarchy; |
| |
| bool oom_lock; |
| atomic_t under_oom; |
| |
| atomic_t refcnt; |
| |
| 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; |
| |
| #ifdef CONFIG_INET |
| struct tcp_memcontrol tcp_mem; |
| #endif |
| }; |
| |
| /* Stuffs for move charges at task migration. */ |
| /* |
| * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a |
| * left-shifted bitmap of these types. |
| */ |
| enum move_type { |
| MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */ |
| MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */ |
| NR_MOVE_TYPE, |
| }; |
| |
| /* "mc" and its members are protected by cgroup_mutex */ |
| static struct move_charge_struct { |
| spinlock_t lock; /* for from, to */ |
| struct mem_cgroup *from; |
| struct mem_cgroup *to; |
| unsigned long precharge; |
| unsigned long moved_charge; |
| unsigned long moved_swap; |
| struct task_struct *moving_task; /* a task moving charges */ |
| wait_queue_head_t waitq; /* a waitq for other context */ |
| } mc = { |
| .lock = __SPIN_LOCK_UNLOCKED(mc.lock), |
| .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq), |
| }; |
| |
| static bool move_anon(void) |
| { |
| return test_bit(MOVE_CHARGE_TYPE_ANON, |
| &mc.to->move_charge_at_immigrate); |
| } |
| |
| static bool move_file(void) |
| { |
| return test_bit(MOVE_CHARGE_TYPE_FILE, |
| &mc.to->move_charge_at_immigrate); |
| } |
| |
| /* |
| * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft |
| * limit reclaim to prevent infinite loops, if they ever occur. |
| */ |
| #define MEM_CGROUP_MAX_RECLAIM_LOOPS (100) |
| #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS (2) |
| |
| enum charge_type { |
| MEM_CGROUP_CHARGE_TYPE_CACHE = 0, |
| MEM_CGROUP_CHARGE_TYPE_MAPPED, |
| MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */ |
| MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */ |
| MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */ |
| MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */ |
| NR_CHARGE_TYPE, |
| }; |
| |
| /* for encoding cft->private value on file */ |
| #define _MEM (0) |
| #define _MEMSWAP (1) |
| #define _OOM_TYPE (2) |
| #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val)) |
| #define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff) |
| #define MEMFILE_ATTR(val) ((val) & 0xffff) |
| /* Used for OOM nofiier */ |
| #define OOM_CONTROL (0) |
| |
| /* |
| * Reclaim flags for mem_cgroup_hierarchical_reclaim |
| */ |
| #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0 |
| #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT) |
| #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1 |
| #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT) |
| |
| static void mem_cgroup_get(struct mem_cgroup *memcg); |
| static void mem_cgroup_put(struct mem_cgroup *memcg); |
| |
| /* Writing them here to avoid exposing memcg's inner layout */ |
| #ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM |
| #include <net/sock.h> |
| #include <net/ip.h> |
| |
| static bool mem_cgroup_is_root(struct mem_cgroup *memcg); |
| void sock_update_memcg(struct sock *sk) |
| { |
| if (mem_cgroup_sockets_enabled) { |
| struct mem_cgroup *memcg; |
| |
| BUG_ON(!sk->sk_prot->proto_cgroup); |
| |
| /* Socket cloning can throw us here with sk_cgrp already |
| * filled. It won't however, necessarily happen from |
| * process context. So the test for root memcg given |
| * the current task's memcg won't help us in this case. |
| * |
| * Respecting the original socket's memcg is a better |
| * decision in this case. |
| */ |
| if (sk->sk_cgrp) { |
| BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg)); |
| mem_cgroup_get(sk->sk_cgrp->memcg); |
| return; |
| } |
| |
| rcu_read_lock(); |
| memcg = mem_cgroup_from_task(current); |
| if (!mem_cgroup_is_root(memcg)) { |
| mem_cgroup_get(memcg); |
| sk->sk_cgrp = sk->sk_prot->proto_cgroup(memcg); |
| } |
| rcu_read_unlock(); |
| } |
| } |
| EXPORT_SYMBOL(sock_update_memcg); |
| |
| void sock_release_memcg(struct sock *sk) |
| { |
| if (mem_cgroup_sockets_enabled && sk->sk_cgrp) { |
| struct mem_cgroup *memcg; |
| WARN_ON(!sk->sk_cgrp->memcg); |
| memcg = sk->sk_cgrp->memcg; |
| mem_cgroup_put(memcg); |
| } |
| } |
| |
| #ifdef CONFIG_INET |
| struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg) |
| { |
| if (!memcg || mem_cgroup_is_root(memcg)) |
| return NULL; |
| |
| return &memcg->tcp_mem.cg_proto; |
| } |
| EXPORT_SYMBOL(tcp_proto_cgroup); |
| #endif /* CONFIG_INET */ |
| #endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */ |
| |
| static void drain_all_stock_async(struct mem_cgroup *memcg); |
| |
| static struct mem_cgroup_per_zone * |
| mem_cgroup_zoneinfo(struct mem_cgroup *memcg, int nid, int zid) |
| { |
| return &memcg->info.nodeinfo[nid]->zoneinfo[zid]; |
| } |
| |
| struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg) |
| { |
| return &memcg->css; |
| } |
| |
| static struct mem_cgroup_per_zone * |
| page_cgroup_zoneinfo(struct mem_cgroup *memcg, struct page *page) |
| { |
| int nid = page_to_nid(page); |
| int zid = page_zonenum(page); |
| |
| return mem_cgroup_zoneinfo(memcg, 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 *memcg, |
| 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 *memcg, |
| 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 *memcg, |
| struct mem_cgroup_per_zone *mz, |
| struct mem_cgroup_tree_per_zone *mctz) |
| { |
| spin_lock(&mctz->lock); |
| __mem_cgroup_remove_exceeded(memcg, mz, mctz); |
| spin_unlock(&mctz->lock); |
| } |
| |
| |
| static void mem_cgroup_update_tree(struct mem_cgroup *memcg, 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 (; memcg; memcg = parent_mem_cgroup(memcg)) { |
| mz = mem_cgroup_zoneinfo(memcg, nid, zid); |
| excess = res_counter_soft_limit_excess(&memcg->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(memcg, mz, mctz); |
| /* |
| * Insert again. mz->usage_in_excess will be updated. |
| * If excess is 0, no tree ops. |
| */ |
| __mem_cgroup_insert_exceeded(memcg, mz, mctz, excess); |
| spin_unlock(&mctz->lock); |
| } |
| } |
| } |
| |
| static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg) |
| { |
| int node, zone; |
| struct mem_cgroup_per_zone *mz; |
| struct mem_cgroup_tree_per_zone *mctz; |
| |
| for_each_node(node) { |
| for (zone = 0; zone < MAX_NR_ZONES; zone++) { |
| mz = mem_cgroup_zoneinfo(memcg, node, zone); |
| mctz = soft_limit_tree_node_zone(node, zone); |
| mem_cgroup_remove_exceeded(memcg, mz, mctz); |
| } |
| } |
| } |
| |
| static struct mem_cgroup_per_zone * |
| __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) |
| { |
| struct rb_node *rightmost = NULL; |
| struct mem_cgroup_per_zone *mz; |
| |
| retry: |
| mz = NULL; |
| rightmost = rb_last(&mctz->rb_root); |
| if (!rightmost) |
| goto done; /* Nothing to reclaim from */ |
| |
| mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node); |
| /* |
| * Remove the node now but someone else can add it back, |
| * we will to add it back at the end of reclaim to its correct |
| * position in the tree. |
| */ |
| __mem_cgroup_remove_exceeded(mz->mem, mz, mctz); |
| if (!res_counter_soft_limit_excess(&mz->mem->res) || |
| !css_tryget(&mz->mem->css)) |
| goto retry; |
| done: |
| return mz; |
| } |
| |
| static struct mem_cgroup_per_zone * |
| mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) |
| { |
| struct mem_cgroup_per_zone *mz; |
| |
| spin_lock(&mctz->lock); |
| mz = __mem_cgroup_largest_soft_limit_node(mctz); |
| spin_unlock(&mctz->lock); |
| return mz; |
| } |
| |
| /* |
| * Implementation Note: reading percpu statistics for memcg. |
| * |
| * Both of vmstat[] and percpu_counter has threshold and do periodic |
| * synchronization to implement "quick" read. There are trade-off between |
| * reading cost and precision of value. Then, we may have a chance to implement |
| * a periodic synchronizion of counter in memcg's counter. |
| * |
| * But this _read() function is used for user interface now. The user accounts |
| * memory usage by memory cgroup and he _always_ requires exact value because |
| * he accounts memory. Even if we provide quick-and-fuzzy read, we always |
| * have to visit all online cpus and make sum. So, for now, unnecessary |
| * synchronization is not implemented. (just implemented for cpu hotplug) |
| * |
| * If there are kernel internal actions which can make use of some not-exact |
| * value, and reading all cpu value can be performance bottleneck in some |
| * common workload, threashold and synchonization as vmstat[] should be |
| * implemented. |
| */ |
| static long mem_cgroup_read_stat(struct mem_cgroup *memcg, |
| enum mem_cgroup_stat_index idx) |
| { |
| long val = 0; |
| int cpu; |
| |
| get_online_cpus(); |
| for_each_online_cpu(cpu) |
| val += per_cpu(memcg->stat->count[idx], cpu); |
| #ifdef CONFIG_HOTPLUG_CPU |
| spin_lock(&memcg->pcp_counter_lock); |
| val += memcg->nocpu_base.count[idx]; |
| spin_unlock(&memcg->pcp_counter_lock); |
| #endif |
| put_online_cpus(); |
| return val; |
| } |
| |
| static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg, |
| bool charge) |
| { |
| int val = (charge) ? 1 : -1; |
| this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAPOUT], val); |
| } |
| |
| static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg, |
| enum mem_cgroup_events_index idx) |
| { |
| unsigned long val = 0; |
| int cpu; |
| |
| for_each_online_cpu(cpu) |
| val += per_cpu(memcg->stat->events[idx], cpu); |
| #ifdef CONFIG_HOTPLUG_CPU |
| spin_lock(&memcg->pcp_counter_lock); |
| val += memcg->nocpu_base.events[idx]; |
| spin_unlock(&memcg->pcp_counter_lock); |
| #endif |
| return val; |
| } |
| |
| static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, |
| bool file, int nr_pages) |
| { |
| preempt_disable(); |
| |
| if (file) |
| __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE], |
| nr_pages); |
| else |
| __this_cpu_add(memcg->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(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]); |
| else { |
| __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]); |
| nr_pages = -nr_pages; /* for event */ |
| } |
| |
| __this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_COUNT], nr_pages); |
| |
| preempt_enable(); |
| } |
| |
| unsigned long |
| mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid, |
| unsigned int lru_mask) |
| { |
| struct mem_cgroup_per_zone *mz; |
| enum lru_list l; |
| unsigned long ret = 0; |
| |
| mz = mem_cgroup_zoneinfo(memcg, nid, zid); |
| |
| for_each_lru(l) { |
| if (BIT(l) & lru_mask) |
| ret += MEM_CGROUP_ZSTAT(mz, l); |
| } |
| return ret; |
| } |
| |
| static unsigned long |
| mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg, |
| int nid, unsigned int lru_mask) |
| { |
| u64 total = 0; |
| int zid; |
| |
| for (zid = 0; zid < MAX_NR_ZONES; zid++) |
| total += mem_cgroup_zone_nr_lru_pages(memcg, |
| nid, zid, lru_mask); |
| |
| return total; |
| } |
| |
| static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg, |
| unsigned int lru_mask) |
| { |
| int nid; |
| u64 total = 0; |
| |
| for_each_node_state(nid, N_HIGH_MEMORY) |
| total += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask); |
| return total; |
| } |
| |
| static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, |
| enum mem_cgroup_events_target target) |
| { |
| unsigned long val, next; |
| |
| val = __this_cpu_read(memcg->stat->events[MEM_CGROUP_EVENTS_COUNT]); |
| next = __this_cpu_read(memcg->stat->targets[target]); |
| /* from time_after() in jiffies.h */ |
| if ((long)next - (long)val < 0) { |
| switch (target) { |
| case MEM_CGROUP_TARGET_THRESH: |
| next = val + THRESHOLDS_EVENTS_TARGET; |
| break; |
| case MEM_CGROUP_TARGET_SOFTLIMIT: |
| next = val + SOFTLIMIT_EVENTS_TARGET; |
| break; |
| case MEM_CGROUP_TARGET_NUMAINFO: |
| next = val + NUMAINFO_EVENTS_TARGET; |
| break; |
| default: |
| break; |
| } |
| __this_cpu_write(memcg->stat->targets[target], next); |
| return true; |
| } |
| return false; |
| } |
| |
| /* |
| * Check events in order. |
| * |
| */ |
| static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) |
| { |
| preempt_disable(); |
| /* threshold event is triggered in finer grain than soft limit */ |
| if (unlikely(mem_cgroup_event_ratelimit(memcg, |
| MEM_CGROUP_TARGET_THRESH))) { |
| bool do_softlimit; |
| bool do_numainfo __maybe_unused; |
| |
| do_softlimit = mem_cgroup_event_ratelimit(memcg, |
| MEM_CGROUP_TARGET_SOFTLIMIT); |
| #if MAX_NUMNODES > 1 |
| do_numainfo = mem_cgroup_event_ratelimit(memcg, |
| MEM_CGROUP_TARGET_NUMAINFO); |
| #endif |
| preempt_enable(); |
| |
| mem_cgroup_threshold(memcg); |
| if (unlikely(do_softlimit)) |
| mem_cgroup_update_tree(memcg, page); |
| #if MAX_NUMNODES > 1 |
| if (unlikely(do_numainfo)) |
| atomic_inc(&memcg->numainfo_events); |
| #endif |
| } else |
| preempt_enable(); |
| } |
| |
| struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) |
| { |
| return container_of(cgroup_subsys_state(cont, |
| mem_cgroup_subsys_id), struct mem_cgroup, |
| css); |
| } |
| |
| struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) |
| { |
| /* |
| * mm_update_next_owner() may clear mm->owner to NULL |
| * if it races with swapoff, page migration, etc. |
| * So this can be called with p == NULL. |
| */ |
| if (unlikely(!p)) |
| return NULL; |
| |
| return container_of(task_subsys_state(p, mem_cgroup_subsys_id), |
| struct mem_cgroup, css); |
| } |
| |
| struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) |
| { |
| struct mem_cgroup *memcg = 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 { |
| memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); |
| if (unlikely(!memcg)) |
| break; |
| } while (!css_tryget(&memcg->css)); |
| rcu_read_unlock(); |
| return memcg; |
| } |
| |
| /** |
| * mem_cgroup_iter - iterate over memory cgroup hierarchy |
| * @root: hierarchy root |
| * @prev: previously returned memcg, NULL on first invocation |
| * @reclaim: cookie for shared reclaim walks, NULL for full walks |
| * |
| * Returns references to children of the hierarchy below @root, or |
| * @root itself, or %NULL after a full round-trip. |
| * |
| * Caller must pass the return value in @prev on subsequent |
| * invocations for reference counting, or use mem_cgroup_iter_break() |
| * to cancel a hierarchy walk before the round-trip is complete. |
| * |
| * Reclaimers can specify a zone and a priority level in @reclaim to |
| * divide up the memcgs in the hierarchy among all concurrent |
| * reclaimers operating on the same zone and priority. |
| */ |
| struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, |
| struct mem_cgroup *prev, |
| struct mem_cgroup_reclaim_cookie *reclaim) |
| { |
| struct mem_cgroup *memcg = NULL; |
| int id = 0; |
| |
| if (mem_cgroup_disabled()) |
| return NULL; |
| |
| if (!root) |
| root = root_mem_cgroup; |
| |
| if (prev && !reclaim) |
| id = css_id(&prev->css); |
| |
| if (prev && prev != root) |
| css_put(&prev->css); |
| |
| if (!root->use_hierarchy && root != root_mem_cgroup) { |
| if (prev) |
| return NULL; |
| return root; |
| } |
| |
| while (!memcg) { |
| struct mem_cgroup_reclaim_iter *uninitialized_var(iter); |
| struct cgroup_subsys_state *css; |
| |
| if (reclaim) { |
| int nid = zone_to_nid(reclaim->zone); |
| int zid = zone_idx(reclaim->zone); |
| struct mem_cgroup_per_zone *mz; |
| |
| mz = mem_cgroup_zoneinfo(root, nid, zid); |
| iter = &mz->reclaim_iter[reclaim->priority]; |
| if (prev && reclaim->generation != iter->generation) |
| return NULL; |
| id = iter->position; |
| } |
| |
| rcu_read_lock(); |
| css = css_get_next(&mem_cgroup_subsys, id + 1, &root->css, &id); |
| if (css) { |
| if (css == &root->css || css_tryget(css)) |
| memcg = container_of(css, |
| struct mem_cgroup, css); |
| } else |
| id = 0; |
| rcu_read_unlock(); |
| |
| if (reclaim) { |
| iter->position = id; |
| if (!css) |
| iter->generation++; |
| else if (!prev && memcg) |
| reclaim->generation = iter->generation; |
| } |
| |
| if (prev && !css) |
| return NULL; |
| } |
| return memcg; |
| } |
| |
| /** |
| * mem_cgroup_iter_break - abort a hierarchy walk prematurely |
| * @root: hierarchy root |
| * @prev: last visited hierarchy member as returned by mem_cgroup_iter() |
| */ |
| void mem_cgroup_iter_break(struct mem_cgroup *root, |
| struct mem_cgroup *prev) |
| { |
| if (!root) |
| root = root_mem_cgroup; |
| if (prev && prev != root) |
| css_put(&prev->css); |
| } |
| |
| /* |
| * Iteration constructs for visiting all cgroups (under a tree). If |
| * loops are exited prematurely (break), mem_cgroup_iter_break() must |
| * be used for reference counting. |
| */ |
| #define for_each_mem_cgroup_tree(iter, root) \ |
| for (iter = mem_cgroup_iter(root, NULL, NULL); \ |
| iter != NULL; \ |
| iter = mem_cgroup_iter(root, iter, NULL)) |
| |
| #define for_each_mem_cgroup(iter) \ |
| for (iter = mem_cgroup_iter(NULL, NULL, NULL); \ |
| iter != NULL; \ |
| iter = mem_cgroup_iter(NULL, iter, NULL)) |
| |
| static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg) |
| { |
| return (memcg == root_mem_cgroup); |
| } |
| |
| void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx) |
| { |
| struct mem_cgroup *memcg; |
| |
| if (!mm) |
| return; |
| |
| rcu_read_lock(); |
| memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); |
| if (unlikely(!memcg)) |
| goto out; |
| |
| switch (idx) { |
| case PGFAULT: |
| this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]); |
| break; |
| case PGMAJFAULT: |
| this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]); |
| break; |
| default: |
| BUG(); |
| } |
| out: |
| rcu_read_unlock(); |
| } |
| EXPORT_SYMBOL(mem_cgroup_count_vm_event); |
| |
| /** |
| * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg |
| * @zone: zone of the wanted lruvec |
| * @mem: memcg of the wanted lruvec |
| * |
| * Returns the lru list vector holding pages for the given @zone and |
| * @mem. This can be the global zone lruvec, if the memory controller |
| * is disabled. |
| */ |
| struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone, |
| struct mem_cgroup *memcg) |
| { |
| struct mem_cgroup_per_zone *mz; |
| |
| if (mem_cgroup_disabled()) |
| return &zone->lruvec; |
| |
| mz = mem_cgroup_zoneinfo(memcg, zone_to_nid(zone), zone_idx(zone)); |
| return &mz->lruvec; |
| } |
| |
| /* |
| * 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. |
| */ |
| |
| /** |
| * mem_cgroup_lru_add_list - account for adding an lru page and return lruvec |
| * @zone: zone of the page |
| * @page: the page |
| * @lru: current lru |
| * |
| * This function accounts for @page being added to @lru, and returns |
| * the lruvec for the given @zone and the memcg @page is charged to. |
| * |
| * The callsite is then responsible for physically linking the page to |
| * the returned lruvec->lists[@lru]. |
| */ |
| struct lruvec *mem_cgroup_lru_add_list(struct zone *zone, struct page *page, |
| enum lru_list lru) |
| { |
| struct mem_cgroup_per_zone *mz; |
| struct mem_cgroup *memcg; |
| struct page_cgroup *pc; |
| |
| if (mem_cgroup_disabled()) |
| return &zone->lruvec; |
| |
| pc = lookup_page_cgroup(page); |
| memcg = pc->mem_cgroup; |
| |
| /* |
| * Surreptitiously switch any uncharged page to root: |
| * an uncharged page off lru does nothing to secure |
| * its former mem_cgroup from sudden removal. |
| * |
| * Our caller holds lru_lock, and PageCgroupUsed is updated |
| * under page_cgroup lock: between them, they make all uses |
| * of pc->mem_cgroup safe. |
| */ |
| if (!PageCgroupUsed(pc) && memcg != root_mem_cgroup) |
| pc->mem_cgroup = memcg = root_mem_cgroup; |
| |
| mz = page_cgroup_zoneinfo(memcg, page); |
| /* compound_order() is stabilized through lru_lock */ |
| MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page); |
| return &mz->lruvec; |
| } |
| |
| /** |
| * mem_cgroup_lru_del_list - account for removing an lru page |
| * @page: the page |
| * @lru: target lru |
| * |
| * This function accounts for @page being removed from @lru. |
| * |
| * The callsite is then responsible for physically unlinking |
| * @page->lru. |
| */ |
| void mem_cgroup_lru_del_list(struct page *page, enum lru_list lru) |
| { |
| struct mem_cgroup_per_zone *mz; |
| struct mem_cgroup *memcg; |
| struct page_cgroup *pc; |
| |
| if (mem_cgroup_disabled()) |
| return; |
| |
| pc = lookup_page_cgroup(page); |
| memcg = pc->mem_cgroup; |
| VM_BUG_ON(!memcg); |
| mz = page_cgroup_zoneinfo(memcg, page); |
| /* huge page split is done under lru_lock. so, we have no races. */ |
| VM_BUG_ON(MEM_CGROUP_ZSTAT(mz, lru) < (1 << compound_order(page))); |
| MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page); |
| } |
| |
| void mem_cgroup_lru_del(struct page *page) |
| { |
| mem_cgroup_lru_del_list(page, page_lru(page)); |
| } |
| |
| /** |
| * mem_cgroup_lru_move_lists - account for moving a page between lrus |
| * @zone: zone of the page |
| * @page: the page |
| * @from: current lru |
| * @to: target lru |
| * |
| * This function accounts for @page being moved between the lrus @from |
| * and @to, and returns the lruvec for the given @zone and the memcg |
| * @page is charged to. |
| * |
| * The callsite is then responsible for physically relinking |
| * @page->lru to the returned lruvec->lists[@to]. |
| */ |
| struct lruvec *mem_cgroup_lru_move_lists(struct zone *zone, |
| struct page *page, |
| enum lru_list from, |
| enum lru_list to) |
| { |
| /* XXX: Optimize this, especially for @from == @to */ |
| mem_cgroup_lru_del_list(page, from); |
| return mem_cgroup_lru_add_list(zone, page, to); |
| } |
| |
| /* |
| * Checks whether given mem is same or in the root_mem_cgroup's |
| * hierarchy subtree |
| */ |
| static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, |
| struct mem_cgroup *memcg) |
| { |
| if (root_memcg != memcg) { |
| return (root_memcg->use_hierarchy && |
| css_is_ancestor(&memcg->css, &root_memcg->css)); |
| } |
| |
| return true; |
| } |
| |
| int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg) |
| { |
| int ret; |
| struct mem_cgroup *curr = NULL; |
| struct task_struct *p; |
| |
| p = find_lock_task_mm(task); |
| if (p) { |
| curr = try_get_mem_cgroup_from_mm(p->mm); |
| task_unlock(p); |
| } else { |
| /* |
| * All threads may have already detached their mm's, but the oom |
| * killer still needs to detect if they have already been oom |
| * killed to prevent needlessly killing additional tasks. |
| */ |
| task_lock(task); |
| curr = mem_cgroup_from_task(task); |
| if (curr) |
| css_get(&curr->css); |
| task_unlock(task); |
| } |
| if (!curr) |
| return 0; |
| /* |
| * We should check use_hierarchy of "memcg" 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 "memcg" in *cgroup* |
| * hierarchy(even if use_hierarchy is disabled in "memcg"). |
| */ |
| ret = mem_cgroup_same_or_subtree(memcg, curr); |
| css_put(&curr->css); |
| return ret; |
| } |
| |
| int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg, struct zone *zone) |
| { |
| unsigned long inactive_ratio; |
| int nid = zone_to_nid(zone); |
| int zid = zone_idx(zone); |
| unsigned long inactive; |
| unsigned long active; |
| unsigned long gb; |
| |
| inactive = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid, |
| BIT(LRU_INACTIVE_ANON)); |
| active = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid, |
| BIT(LRU_ACTIVE_ANON)); |
| |
| gb = (inactive + active) >> (30 - PAGE_SHIFT); |
| if (gb) |
| inactive_ratio = int_sqrt(10 * gb); |
| else |
| inactive_ratio = 1; |
| |
| return inactive * inactive_ratio < active; |
| } |
| |
| int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg, struct zone *zone) |
| { |
| unsigned long active; |
| unsigned long inactive; |
| int zid = zone_idx(zone); |
| int nid = zone_to_nid(zone); |
| |
| inactive = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid, |
| BIT(LRU_INACTIVE_FILE)); |
| active = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid, |
| BIT(LRU_ACTIVE_FILE)); |
| |
| return (active > inactive); |
| } |
| |
| struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg, |
| struct zone *zone) |
| { |
| int nid = zone_to_nid(zone); |
| int zid = zone_idx(zone); |
| struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid); |
| |
| return &mz->reclaim_stat; |
| } |
| |
| struct zone_reclaim_stat * |
| mem_cgroup_get_reclaim_stat_from_page(struct page *page) |
| { |
| struct page_cgroup *pc; |
| struct mem_cgroup_per_zone *mz; |
| |
| if (mem_cgroup_disabled()) |
| return NULL; |
| |
| pc = lookup_page_cgroup(page); |
| if (!PageCgroupUsed(pc)) |
| return NULL; |
| /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ |
| smp_rmb(); |
| mz = page_cgroup_zoneinfo(pc->mem_cgroup, page); |
| return &mz->reclaim_stat; |
| } |
| |
| #define mem_cgroup_from_res_counter(counter, member) \ |
| container_of(counter, struct mem_cgroup, member) |
| |
| /** |
| * mem_cgroup_margin - calculate chargeable space of a memory cgroup |
| * @mem: the memory cgroup |
| * |
| * Returns the maximum amount of memory @mem can be charged with, in |
| * pages. |
| */ |
| static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg) |
| { |
| unsigned long long margin; |
| |
| margin = res_counter_margin(&memcg->res); |
| if (do_swap_account) |
| margin = min(margin, res_counter_margin(&memcg->memsw)); |
| return margin >> PAGE_SHIFT; |
| } |
| |
| int mem_cgroup_swappiness(struct mem_cgroup *memcg) |
| { |
| struct cgroup *cgrp = memcg->css.cgroup; |
| |
| /* root ? */ |
| if (cgrp->parent == NULL) |
| return vm_swappiness; |
| |
| return memcg->swappiness; |
| } |
| |
| static void mem_cgroup_start_move(struct mem_cgroup *memcg) |
| { |
| int cpu; |
| |
| get_online_cpus(); |
| spin_lock(&memcg->pcp_counter_lock); |
| for_each_online_cpu(cpu) |
| per_cpu(memcg->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1; |
| memcg->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1; |
| spin_unlock(&memcg->pcp_counter_lock); |
| put_online_cpus(); |
| |
| synchronize_rcu(); |
| } |
| |
| static void mem_cgroup_end_move(struct mem_cgroup *memcg) |
| { |
| int cpu; |
| |
| if (!memcg) |
| return; |
| get_online_cpus(); |
| spin_lock(&memcg->pcp_counter_lock); |
| for_each_online_cpu(cpu) |
| per_cpu(memcg->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1; |
| memcg->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1; |
| spin_unlock(&memcg->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 *memcg) |
| { |
| VM_BUG_ON(!rcu_read_lock_held()); |
| return this_cpu_read(memcg->stat->count[MEM_CGROUP_ON_MOVE]) > 0; |
| } |
| |
| static bool mem_cgroup_under_move(struct mem_cgroup *memcg) |
| { |
| struct mem_cgroup *from; |
| struct mem_cgroup *to; |
| bool ret = false; |
| /* |
| * Unlike task_move routines, we access mc.to, mc.from not under |
| * mutual exclusion by cgroup_mutex. Here, we take spinlock instead. |
| */ |
| spin_lock(&mc.lock); |
| from = mc.from; |
| to = mc.to; |
| if (!from) |
| goto unlock; |
| |
| ret = mem_cgroup_same_or_subtree(memcg, from) |
| || mem_cgroup_same_or_subtree(memcg, to); |
| unlock: |
| spin_unlock(&mc.lock); |
| return ret; |
| } |
| |
| static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg) |
| { |
| if (mc.moving_task && current != mc.moving_task) { |
| if (mem_cgroup_under_move(memcg)) { |
| DEFINE_WAIT(wait); |
| prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE); |
| /* moving charge context might have finished. */ |
| if (mc.moving_task) |
| schedule(); |
| finish_wait(&mc.waitq, &wait); |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /** |
| * 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 *memcg) |
| { |
| int num = 0; |
| struct mem_cgroup *iter; |
| |
| for_each_mem_cgroup_tree(iter, memcg) |
| num++; |
| return num; |
| } |
| |
| /* |
| * Return the memory (and swap, if configured) limit for a memcg. |
| */ |
| 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); |
| } |
| |
| static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg, |
| gfp_t gfp_mask, |
| unsigned long flags) |
| { |
| unsigned long total = 0; |
| bool noswap = false; |
| int loop; |
| |
| if (flags & MEM_CGROUP_RECLAIM_NOSWAP) |
| noswap = true; |
| if (!(flags & MEM_CGROUP_RECLAIM_SHRINK) && memcg->memsw_is_minimum) |
| noswap = true; |
| |
| for (loop = 0; loop < MEM_CGROUP_MAX_RECLAIM_LOOPS; loop++) { |
| if (loop) |
| drain_all_stock_async(memcg); |
| total += try_to_free_mem_cgroup_pages(memcg, gfp_mask, noswap); |
| /* |
| * Allow limit shrinkers, which are triggered directly |
| * by userspace, to catch signals and stop reclaim |
| * after minimal progress, regardless of the margin. |
| */ |
| if (total && (flags & MEM_CGROUP_RECLAIM_SHRINK)) |
| break; |
| if (mem_cgroup_margin(memcg)) |
| break; |
| /* |
| * If nothing was reclaimed after two attempts, there |
| * may be no reclaimable pages in this hierarchy. |
| */ |
| if (loop && !total) |
| break; |
| } |
| return total; |
| } |
| |
| /** |
| * test_mem_cgroup_node_reclaimable |
| * @mem: the target memcg |
| * @nid: the node ID to be checked. |
| * @noswap : specify true here if the user wants flle only information. |
| * |
| * This function returns whether the specified memcg contains any |
| * reclaimable pages on a node. Returns true if there are any reclaimable |
| * pages in the node. |
| */ |
| static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg, |
| int nid, bool noswap) |
| { |
| if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE)) |
| return true; |
| if (noswap || !total_swap_pages) |
| return false; |
| if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON)) |
| return true; |
| return false; |
| |
| } |
| #if MAX_NUMNODES > 1 |
| |
| /* |
| * Always updating the nodemask is not very good - even if we have an empty |
| * list or the wrong list here, we can start from some node and traverse all |
| * nodes based on the zonelist. So update the list loosely once per 10 secs. |
| * |
| */ |
| static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg) |
| { |
| int nid; |
| /* |
| * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET |
| * pagein/pageout changes since the last update. |
| */ |
| if (!atomic_read(&memcg->numainfo_events)) |
| return; |
| if (atomic_inc_return(&memcg->numainfo_updating) > 1) |
| return; |
| |
| /* make a nodemask where this memcg uses memory from */ |
| memcg->scan_nodes = node_states[N_HIGH_MEMORY]; |
| |
| for_each_node_mask(nid, node_states[N_HIGH_MEMORY]) { |
| |
| if (!test_mem_cgroup_node_reclaimable(memcg, nid, false)) |
| node_clear(nid, memcg->scan_nodes); |
| } |
| |
| atomic_set(&memcg->numainfo_events, 0); |
| atomic_set(&memcg->numainfo_updating, 0); |
| } |
| |
| /* |
| * Selecting a node where we start reclaim from. Because what we need is just |
| * reducing usage counter, start from anywhere is O,K. Considering |
| * memory reclaim from current node, there are pros. and cons. |
| * |
| * Freeing memory from current node means freeing memory from a node which |
| * we'll use or we've used. So, it may make LRU bad. And if several threads |
| * hit limits, it will see a contention on a node. But freeing from remote |
| * node means more costs for memory reclaim because of memory latency. |
| * |
| * Now, we use round-robin. Better algorithm is welcomed. |
| */ |
| int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) |
| { |
| int node; |
| |
| mem_cgroup_may_update_nodemask(memcg); |
| node = memcg->last_scanned_node; |
| |
| node = next_node(node, memcg->scan_nodes); |
| if (node == MAX_NUMNODES) |
| node = first_node(memcg->scan_nodes); |
| /* |
| * We call this when we hit limit, not when pages are added to LRU. |
| * No LRU may hold pages because all pages are UNEVICTABLE or |
| * memcg is too small and all pages are not on LRU. In that case, |
| * we use curret node. |
| */ |
| if (unlikely(node == MAX_NUMNODES)) |
| node = numa_node_id(); |
| |
| memcg->last_scanned_node = node; |
| return node; |
| } |
| |
| /* |
| * Check all nodes whether it contains reclaimable pages or not. |
| * For quick scan, we make use of scan_nodes. This will allow us to skip |
| * unused nodes. But scan_nodes is lazily updated and may not cotain |
| * enough new information. We need to do double check. |
| */ |
| bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap) |
| { |
| int nid; |
| |
| /* |
| * quick check...making use of scan_node. |
| * We can skip unused nodes. |
| */ |
| if (!nodes_empty(memcg->scan_nodes)) { |
| for (nid = first_node(memcg->scan_nodes); |
| nid < MAX_NUMNODES; |
| nid = next_node(nid, memcg->scan_nodes)) { |
| |
| if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap)) |
| return true; |
| } |
| } |
| /* |
| * Check rest of nodes. |
| */ |
| for_each_node_state(nid, N_HIGH_MEMORY) { |
| if (node_isset(nid, memcg->scan_nodes)) |
| continue; |
| if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap)) |
| return true; |
| } |
| return false; |
| } |
| |
| #else |
| int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) |
| { |
| return 0; |
| } |
| |
| bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap) |
| { |
| return test_mem_cgroup_node_reclaimable(memcg, 0, noswap); |
| } |
| #endif |
| |
| static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg, |
| struct zone *zone, |
| gfp_t gfp_mask, |
| unsigned long *total_scanned) |
| { |
| struct mem_cgroup *victim = NULL; |
| int total = 0; |
| int loop = 0; |
| unsigned long excess; |
| unsigned long nr_scanned; |
| struct mem_cgroup_reclaim_cookie reclaim = { |
| .zone = zone, |
| .priority = 0, |
| }; |
| |
| excess = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT; |
| |
| while (1) { |
| victim = mem_cgroup_iter(root_memcg, victim, &reclaim); |
| if (!victim) { |
| loop++; |
| if (loop >= 2) { |
| /* |
| * If we have not been able to reclaim |
| * anything, it might because there are |
| * no reclaimable pages under this hierarchy |
| */ |
| if (!total) |
| break; |
| /* |
| * We want to do more targeted reclaim. |
| * excess >> 2 is not to excessive so as to |
| * reclaim too much, nor too less that we keep |
| * coming back to reclaim from this cgroup |
| */ |
| if (total >= (excess >> 2) || |
| (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) |
| break; |
| } |
| continue; |
| } |
| if (!mem_cgroup_reclaimable(victim, false)) |
| continue; |
| total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false, |
| zone, &nr_scanned); |
| *total_scanned += nr_scanned; |
| if (!res_counter_soft_limit_excess(&root_memcg->res)) |
| break; |
| } |
| mem_cgroup_iter_break(root_memcg, victim); |
| return total; |
| } |
| |
| /* |
| * Check OOM-Killer is already running under our hierarchy. |
| * If someone is running, return false. |
| * Has to be called with memcg_oom_lock |
| */ |
| static bool mem_cgroup_oom_lock(struct mem_cgroup *memcg) |
| { |
| struct mem_cgroup *iter, *failed = NULL; |
| |
| for_each_mem_cgroup_tree(iter, memcg) { |
| if (iter->oom_lock) { |
| /* |
| * this subtree of our hierarchy is already locked |
| * so we cannot give a lock. |
| */ |
| failed = iter; |
| mem_cgroup_iter_break(memcg, iter); |
| break; |
| } else |
| iter->oom_lock = true; |
| } |
| |
| if (!failed) |
| return true; |
| |
| /* |
| * OK, we failed to lock the whole subtree so we have to clean up |
| * what we set up to the failing subtree |
| */ |
| for_each_mem_cgroup_tree(iter, memcg) { |
| if (iter == failed) { |
| mem_cgroup_iter_break(memcg, iter); |
| break; |
| } |
| iter->oom_lock = false; |
| } |
| return false; |
| } |
| |
| /* |
| * Has to be called with memcg_oom_lock |
| */ |
| static int mem_cgroup_oom_unlock(struct mem_cgroup *memcg) |
| { |
| struct mem_cgroup *iter; |
| |
| for_each_mem_cgroup_tree(iter, memcg) |
| iter->oom_lock = false; |
| return 0; |
| } |
| |
| static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg) |
| { |
| struct mem_cgroup *iter; |
| |
| for_each_mem_cgroup_tree(iter, memcg) |
| atomic_inc(&iter->under_oom); |
| } |
| |
| static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg) |
| { |
| struct mem_cgroup *iter; |
| |
| /* |
| * When a new child is created while the hierarchy is under oom, |
| * mem_cgroup_oom_lock() may not be called. We have to use |
| * atomic_add_unless() here. |
| */ |
| for_each_mem_cgroup_tree(iter, memcg) |
| atomic_add_unless(&iter->under_oom, -1, 0); |
| } |
| |
| static DEFINE_SPINLOCK(memcg_oom_lock); |
| 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_memcg = (struct mem_cgroup *)arg, |
| *oom_wait_memcg; |
| struct oom_wait_info *oom_wait_info; |
| |
| oom_wait_info = container_of(wait, struct oom_wait_info, wait); |
| oom_wait_memcg = oom_wait_info->mem; |
| |
| /* |
| * 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 (!mem_cgroup_same_or_subtree(oom_wait_memcg, wake_memcg) |
| && !mem_cgroup_same_or_subtree(wake_memcg, oom_wait_memcg)) |
| return 0; |
| return autoremove_wake_function(wait, mode, sync, arg); |
| } |
| |
| static void memcg_wakeup_oom(struct mem_cgroup *memcg) |
| { |
| /* for filtering, pass "memcg" as argument. */ |
| __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg); |
| } |
| |
| static void memcg_oom_recover(struct mem_cgroup *memcg) |
| { |
| if (memcg && atomic_read(&memcg->under_oom)) |
| memcg_wakeup_oom(memcg); |
| } |
| |
| /* |
| * try to call OOM killer. returns false if we should exit memory-reclaim loop. |
| */ |
| bool mem_cgroup_handle_oom(struct mem_cgroup *memcg, gfp_t mask) |
| { |
| struct oom_wait_info owait; |
| bool locked, need_to_kill; |
| |
| owait.mem = memcg; |
| 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; |
| mem_cgroup_mark_under_oom(memcg); |
| |
| /* At first, try to OOM lock hierarchy under memcg.*/ |
| spin_lock(&memcg_oom_lock); |
| locked = mem_cgroup_oom_lock(memcg); |
| /* |
| * 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 || memcg->oom_kill_disable) |
| need_to_kill = false; |
| if (locked) |
| mem_cgroup_oom_notify(memcg); |
| spin_unlock(&memcg_oom_lock); |
| |
| if (need_to_kill) { |
| finish_wait(&memcg_oom_waitq, &owait.wait); |
| mem_cgroup_out_of_memory(memcg, mask); |
| } else { |
| schedule(); |
| finish_wait(&memcg_oom_waitq, &owait.wait); |
| } |
| spin_lock(&memcg_oom_lock); |
| if (locked) |
| mem_cgroup_oom_unlock(memcg); |
| memcg_wakeup_oom(memcg); |
| spin_unlock(&memcg_oom_lock); |
| |
| mem_cgroup_unmark_under_oom(memcg); |
| |
| if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current)) |
| return false; |
| /* Give chance to dying process */ |
| schedule_timeout_uninterruptible(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 *memcg; |
| struct page_cgroup *pc = lookup_page_cgroup(page); |
| bool need_unlock = false; |
| unsigned long uninitialized_var(flags); |
| |
| if (mem_cgroup_disabled()) |
| return; |
| |
| rcu_read_lock(); |
| memcg = pc->mem_cgroup; |
| if (unlikely(!memcg || !PageCgroupUsed(pc))) |
| goto out; |
| /* pc->mem_cgroup is unstable ? */ |
| if (unlikely(mem_cgroup_stealed(memcg)) || PageTransHuge(page)) { |
| /* take a lock against to access pc->mem_cgroup */ |
| move_lock_page_cgroup(pc, &flags); |
| need_unlock = true; |
| memcg = pc->mem_cgroup; |
| if (!memcg || !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(memcg->stat->count[idx], val); |
| |
| out: |
| if (unlikely(need_unlock)) |
| move_unlock_page_cgroup(pc, &flags); |
| rcu_read_unlock(); |
| return; |
| } |
| EXPORT_SYMBOL(mem_cgroup_update_page_stat); |
| |
| /* |
| * size of first charge trial. "32" comes from vmscan.c's magic value. |
| * TODO: maybe necessary to use big numbers in big irons. |
| */ |
| #define CHARGE_BATCH 32U |
| struct memcg_stock_pcp { |
| struct mem_cgroup *cached; /* this never be root cgroup */ |
| unsigned int nr_pages; |
| struct work_struct work; |
| unsigned long flags; |
| #define FLUSHING_CACHED_CHARGE (0) |
| }; |
| static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock); |
| static DEFINE_MUTEX(percpu_charge_mutex); |
| |
| /* |
| * Try to consume stocked charge on this cpu. If success, one page is consumed |
| * from local stock and true is returned. If the stock is 0 or charges from a |
| * cgroup which is not current target, returns false. This stock will be |
| * refilled. |
| */ |
| static bool consume_stock(struct mem_cgroup *memcg) |
| { |
| struct memcg_stock_pcp *stock; |
| bool ret = true; |
| |
| stock = &get_cpu_var(memcg_stock); |
| if (memcg == stock->cached && stock->nr_pages) |
| stock->nr_pages--; |
| else /* need to call res_counter_charge */ |
| ret = false; |
| put_cpu_var(memcg_stock); |
| return ret; |
| } |
| |
| /* |
| * Returns stocks cached in percpu to res_counter and reset cached information. |
| */ |
| static void drain_stock(struct memcg_stock_pcp *stock) |
| { |
| struct mem_cgroup *old = stock->cached; |
| |
| if (stock->nr_pages) { |
| unsigned long bytes = stock->nr_pages * PAGE_SIZE; |
| |
| res_counter_uncharge(&old->res, bytes); |
| if (do_swap_account) |
| res_counter_uncharge(&old->memsw, bytes); |
| stock->nr_pages = 0; |
| } |
| stock->cached = NULL; |
| } |
| |
| /* |
| * This must be called under preempt disabled or must be called by |
| * a thread which is pinned to local cpu. |
| */ |
| static void drain_local_stock(struct work_struct *dummy) |
| { |
| struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock); |
| drain_stock(stock); |
| clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); |
| } |
| |
| /* |
| * Cache charges(val) which is from res_counter, to local per_cpu area. |
| * This will be consumed by consume_stock() function, later. |
| */ |
| static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages) |
| { |
| struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock); |
| |
| if (stock->cached != memcg) { /* reset if necessary */ |
| drain_stock(stock); |
| stock->cached = memcg; |
| } |
| stock->nr_pages += nr_pages; |
| put_cpu_var(memcg_stock); |
| } |
| |
| /* |
| * Drains all per-CPU charge caches for given root_memcg resp. subtree |
| * of the hierarchy under it. sync flag says whether we should block |
| * until the work is done. |
| */ |
| static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync) |
| { |
| int cpu, curcpu; |
| |
| /* Notify other cpus that system-wide "drain" is running */ |
| get_online_cpus(); |
| curcpu = get_cpu(); |
| for_each_online_cpu(cpu) { |
| struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); |
| struct mem_cgroup *memcg; |
| |
| memcg = stock->cached; |
| if (!memcg || !stock->nr_pages) |
| continue; |
| if (!mem_cgroup_same_or_subtree(root_memcg, memcg)) |
| continue; |
| if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) { |
| if (cpu == curcpu) |
| drain_local_stock(&stock->work); |
| else |
| schedule_work_on(cpu, &stock->work); |
| } |
| } |
| put_cpu(); |
| |
| if (!sync) |
| goto out; |
| |
| for_each_online_cpu(cpu) { |
| struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); |
| if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) |
| flush_work(&stock->work); |
| } |
| out: |
| put_online_cpus(); |
| } |
| |
| /* |
| * Tries to drain stocked charges in other cpus. This function is asynchronous |
| * and just put a work per cpu for draining localy on each cpu. Caller can |
| * expects some charges will be back to res_counter later but cannot wait for |
| * it. |
| */ |
| static void drain_all_stock_async(struct mem_cgroup *root_memcg) |
| { |
| /* |
| * If someone calls draining, avoid adding more kworker runs. |
| */ |
| if (!mutex_trylock(&percpu_charge_mutex)) |
| return; |
| drain_all_stock(root_memcg, false); |
| mutex_unlock(&percpu_charge_mutex); |
| } |
| |
| /* This is a synchronous drain interface. */ |
| static void drain_all_stock_sync(struct mem_cgroup *root_memcg) |
| { |
| /* called when force_empty is called */ |
| mutex_lock(&percpu_charge_mutex); |
| drain_all_stock(root_memcg, true); |
| mutex_unlock(&percpu_charge_mutex); |
| } |
| |
| /* |
| * This function drains percpu counter value from DEAD cpu and |
| * move it to local cpu. Note that this function can be preempted. |
| */ |
| static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu) |
| { |
| int i; |
| |
| spin_lock(&memcg->pcp_counter_lock); |
| for (i = 0; i < MEM_CGROUP_STAT_DATA; i++) { |
| long x = per_cpu(memcg->stat->count[i], cpu); |
| |
| per_cpu(memcg->stat->count[i], cpu) = 0; |
| memcg->nocpu_base.count[i] += x; |
| } |
| for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) { |
| unsigned long x = per_cpu(memcg->stat->events[i], cpu); |
| |
| per_cpu(memcg->stat->events[i], cpu) = 0; |
| memcg->nocpu_base.events[i] += x; |
| } |
| /* need to clear ON_MOVE value, works as a kind of lock. */ |
| per_cpu(memcg->stat->count[MEM_CGROUP_ON_MOVE], cpu) = 0; |
| spin_unlock(&memcg->pcp_counter_lock); |
| } |
| |
| static void synchronize_mem_cgroup_on_move(struct mem_cgroup *memcg, int cpu) |
| { |
| int idx = MEM_CGROUP_ON_MOVE; |
| |
| spin_lock(&memcg->pcp_counter_lock); |
| per_cpu(memcg->stat->count[idx], cpu) = memcg->nocpu_base.count[idx]; |
| spin_unlock(&memcg->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(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(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 *memcg, gfp_t gfp_mask, |
| unsigned int nr_pages, bool oom_check) |
| { |
| unsigned long csize = nr_pages * PAGE_SIZE; |
| struct mem_cgroup *mem_over_limit; |
| struct res_counter *fail_res; |
| unsigned long flags = 0; |
| int ret; |
| |
| ret = res_counter_charge(&memcg->res, csize, &fail_res); |
| |
| if (likely(!ret)) { |
| if (!do_swap_account) |
| return CHARGE_OK; |
| ret = res_counter_charge(&memcg->memsw, csize, &fail_res); |
| if (likely(!ret)) |
| return CHARGE_OK; |
| |
| res_counter_uncharge(&memcg->res, csize); |
| mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw); |
| flags |= MEM_CGROUP_RECLAIM_NOSWAP; |
| } else |
| mem_over_limit = mem_cgroup_from_res_counter(fail_res, res); |
| /* |
| * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch |
| * of regular pages (CHARGE_BATCH), or a single regular page (1). |
| * |
| * Never reclaim on behalf of optional batching, retry with a |
| * single page instead. |
| */ |
| if (nr_pages == CHARGE_BATCH) |
| return CHARGE_RETRY; |
| |
| if (!(gfp_mask & __GFP_WAIT)) |
| return CHARGE_WOULDBLOCK; |
| |
| ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags); |
| if (mem_cgroup_margin(mem_over_limit) >= nr_pages) |
| return CHARGE_RETRY; |
| /* |
| * Even though the limit is exceeded at this point, reclaim |
| * may have been able to free some pages. Retry the charge |
| * before killing the task. |
| * |
| * Only for regular pages, though: huge pages are rather |
| * unlikely to succeed so close to the limit, and we fall back |
| * to regular pages anyway in case of failure. |
| */ |
| if (nr_pages == 1 && ret) |
| return CHARGE_RETRY; |
| |
| /* |
| * At task move, charge accounts can be doubly counted. So, it's |
| * better to wait until the end of task_move if something is going on. |
| */ |
| if (mem_cgroup_wait_acct_move(mem_over_limit)) |
| return CHARGE_RETRY; |
| |
| /* If we don't need to call oom-killer at el, return immediately */ |
| if (!oom_check) |
| return CHARGE_NOMEM; |
| /* check OOM */ |
| if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask)) |
| return CHARGE_OOM_DIE; |
| |
| return CHARGE_RETRY; |
| } |
| |
| /* |
| * __mem_cgroup_try_charge() does |
| * 1. detect memcg to be charged against from passed *mm and *ptr, |
| * 2. update res_counter |
| * 3. call memory reclaim if necessary. |
| * |
| * In some special case, if the task is fatal, fatal_signal_pending() or |
| * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup |
| * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon |
| * as possible without any hazards. 2: all pages should have a valid |
| * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg |
| * pointer, that is treated as a charge to root_mem_cgroup. |
| * |
| * So __mem_cgroup_try_charge() will return |
| * 0 ... on success, filling *ptr with a valid memcg pointer. |
| * -ENOMEM ... charge failure because of resource limits. |
| * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup. |
| * |
| * Unlike the exported interface, an "oom" parameter is added. if oom==true, |
| * the oom-killer can be invoked. |
| */ |
| static int __mem_cgroup_try_charge(struct mm_struct *mm, |
| gfp_t gfp_mask, |
| unsigned int nr_pages, |
| struct mem_cgroup **ptr, |
| bool oom) |
| { |
| unsigned int batch = max(CHARGE_BATCH, nr_pages); |
| int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; |
| struct mem_cgroup *memcg = NULL; |
| int ret; |
| |
| /* |
| * Unlike gloval-vm's OOM-kill, we're not in memory shortage |
| * in system level. So, allow to go ahead dying process in addition to |
| * MEMDIE process. |
| */ |
| if (unlikely(test_thread_flag(TIF_MEMDIE) |
| || fatal_signal_pending(current))) |
| goto bypass; |
| |
| /* |
| * We always charge the cgroup the mm_struct belongs to. |
| * The mm_struct's mem_cgroup changes on task migration if the |
| * thread group leader migrates. It's possible that mm is not |
| * set, if so charge the init_mm (happens for pagecache usage). |
| */ |
| if (!*ptr && !mm) |
| *ptr = root_mem_cgroup; |
| again: |
| if (*ptr) { /* css should be a valid one */ |
| memcg = *ptr; |
| VM_BUG_ON(css_is_removed(&memcg->css)); |
| if (mem_cgroup_is_root(memcg)) |
| goto done; |
| if (nr_pages == 1 && consume_stock(memcg)) |
| goto done; |
| css_get(&memcg->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, "memcg" 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. |
| */ |
| memcg = mem_cgroup_from_task(p); |
| if (!memcg) |
| memcg = root_mem_cgroup; |
| if (mem_cgroup_is_root(memcg)) { |
| rcu_read_unlock(); |
| goto done; |
| } |
| if (nr_pages == 1 && consume_stock(memcg)) { |
| /* |
| * 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(&memcg->css)) { |
| rcu_read_unlock(); |
| goto again; |
| } |
| rcu_read_unlock(); |
| } |
| |
| do { |
| bool oom_check; |
| |
| /* If killed, bypass charge */ |
| if (fatal_signal_pending(current)) { |
| css_put(&memcg->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(memcg, gfp_mask, batch, oom_check); |
| switch (ret) { |
| case CHARGE_OK: |
| break; |
| case CHARGE_RETRY: /* not in OOM situation but retry */ |
| batch = nr_pages; |
| css_put(&memcg->css); |
| memcg = NULL; |
| goto again; |
| case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */ |
| css_put(&memcg->css); |
| goto nomem; |
| case CHARGE_NOMEM: /* OOM routine works */ |
| if (!oom) { |
| css_put(&memcg->css); |
| goto nomem; |
| } |
| /* If oom, we never return -ENOMEM */ |
| nr_oom_retries--; |
| break; |
| case CHARGE_OOM_DIE: /* Killed by OOM Killer */ |
| css_put(&memcg->css); |
| goto bypass; |
| } |
| } while (ret != CHARGE_OK); |
| |
| if (batch > nr_pages) |
| refill_stock(memcg, batch - nr_pages); |
| css_put(&memcg->css); |
| done: |
| *ptr = memcg; |
| return 0; |
| nomem: |
| *ptr = NULL; |
| return -ENOMEM; |
| bypass: |
| *ptr = root_mem_cgroup; |
| return -EINTR; |
| } |
| |
| /* |
| * 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 *memcg, |
| unsigned int nr_pages) |
| { |
| if (!mem_cgroup_is_root(memcg)) { |
| unsigned long bytes = nr_pages * PAGE_SIZE; |
| |
| res_counter_uncharge(&memcg->res, bytes); |
| if (do_swap_account) |
| res_counter_uncharge(&memcg->memsw, bytes); |
| } |
| } |
| |
| /* |
| * A helper function to get mem_cgroup from ID. must be called under |
| * rcu_read_lock(). The caller must check css_is_removed() or some if |
| * it's concern. (dropping refcnt from swap can be called against removed |
| * memcg.) |
| */ |
| static struct mem_cgroup *mem_cgroup_lookup(unsigned short id) |
| { |
| struct cgroup_subsys_state *css; |
| |
| /* ID 0 is unused ID */ |
| if (!id) |
| return NULL; |
| css = css_lookup(&mem_cgroup_subsys, id); |
| if (!css) |
| return NULL; |
| return container_of(css, struct mem_cgroup, css); |
| } |
| |
| struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) |
| { |
| struct mem_cgroup *memcg = 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)) { |
| memcg = pc->mem_cgroup; |
| if (memcg && !css_tryget(&memcg->css)) |
| memcg = NULL; |
| } else if (PageSwapCache(page)) { |
| ent.val = page_private(page); |
| id = lookup_swap_cgroup_id(ent); |
| rcu_read_lock(); |
| memcg = mem_cgroup_lookup(id); |
| if (memcg && !css_tryget(&memcg->css)) |
| memcg = NULL; |
| rcu_read_unlock(); |
| } |
| unlock_page_cgroup(pc); |
| return memcg; |
| } |
| |
| static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, |
| struct page *page, |
| unsigned int nr_pages, |
| struct page_cgroup *pc, |
| enum charge_type ctype, |
| bool lrucare) |
| { |
| struct zone *uninitialized_var(zone); |
| bool was_on_lru = false; |
| |
| lock_page_cgroup(pc); |
| if (unlikely(PageCgroupUsed(pc))) { |
| unlock_page_cgroup(pc); |
| __mem_cgroup_cancel_charge(memcg, nr_pages); |
| return; |
| } |
| /* |
| * we don't need page_cgroup_lock about tail pages, becase they are not |
| * accessed by any other context at this point. |
| */ |
| |
| /* |
| * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page |
| * may already be on some other mem_cgroup's LRU. Take care of it. |
| */ |
| if (lrucare) { |
| zone = page_zone(page); |
| spin_lock_irq(&zone->lru_lock); |
| if (PageLRU(page)) { |
| ClearPageLRU(page); |
| del_page_from_lru_list(zone, page, page_lru(page)); |
| was_on_lru = true; |
| } |
| } |
| |
| pc->mem_cgroup = memcg; |
| /* |
| * 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; |
| } |
| |
| if (lrucare) { |
| if (was_on_lru) { |
| VM_BUG_ON(PageLRU(page)); |
| SetPageLRU(page); |
| add_page_to_lru_list(zone, page, page_lru(page)); |
| } |
| spin_unlock_irq(&zone->lru_lock); |
| } |
| |
| mem_cgroup_charge_statistics(memcg, 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(memcg, page); |
| } |
| |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| |
| #define PCGF_NOCOPY_AT_SPLIT ((1 << PCG_LOCK) | (1 << PCG_MOVE_LOCK) |\ |
| (1 << PCG_MIGRATION)) |
| /* |
| * Because tail pages are not marked as "used", set it. We're under |
| * zone->lru_lock, 'splitting on pmd' and compound_lock. |
| * charge/uncharge will be never happen and move_account() is done under |
| * compound_lock(), so we don't have to take care of races. |
| */ |
| void mem_cgroup_split_huge_fixup(struct page *head) |
| { |
| struct page_cgroup *head_pc = lookup_page_cgroup(head); |
| struct page_cgroup *pc; |
| int i; |
| |
| if (mem_cgroup_disabled()) |
| return; |
| for (i = 1; i < HPAGE_PMD_NR; i++) { |
| pc = head_pc + i; |
| pc->mem_cgroup = head_pc->mem_cgroup; |
| smp_wmb();/* see __commit_charge() */ |
| pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT; |
| } |
| } |
| #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ |
| |
| /** |
| * mem_cgroup_move_account - move account of the page |
| * @page: the page |
| * @nr_pages: number of regular pages (>1 for huge pages) |
| * @pc: page_cgroup of the page. |
| * @from: mem_cgroup which the page is moved from. |
| * @to: mem_cgroup which the page is moved to. @from != @to. |
| * @uncharge: whether we should call uncharge and css_put against @from. |
| * |
| * The caller must confirm following. |
| * - page is not on LRU (isolate_page() is useful.) |
| * - compound_lock is held when nr_pages > 1 |
| * |
| * This function doesn't do "charge" nor css_get to new cgroup. It should be |
| * done by a caller(__mem_cgroup_try_charge would be useful). If @uncharge is |
| * true, this function does "uncharge" from old cgroup, but it doesn't if |
| * @uncharge is false, so a caller should do "uncharge". |
| */ |
| static int mem_cgroup_move_account(struct page *page, |
| unsigned int nr_pages, |
| struct page_cgroup *pc, |
| struct mem_cgroup *from, |
| struct mem_cgroup *to, |
| bool uncharge) |
| { |
| unsigned long flags; |
| int ret; |
| |
| VM_BUG_ON(from == to); |
| VM_BUG_ON(PageLRU(page)); |
| /* |
| * The page is isolated from LRU. So, collapse function |
| * will not handle this page. But page splitting can happen. |
| * Do this check under compound_page_lock(). The caller should |
| * hold it. |
| */ |
| ret = -EBUSY; |
| if (nr_pages > 1 && !PageTransHuge(page)) |
| goto out; |
| |
| lock_page_cgroup(pc); |
| |
| ret = -EINVAL; |
| if (!PageCgroupUsed(pc) || pc->mem_cgroup != from) |
| goto unlock; |
| |
| move_lock_page_cgroup(pc, &flags); |
| |
| if (PageCgroupFileMapped(pc)) { |
| /* Update mapped_file data for mem_cgroup */ |
| preempt_disable(); |
| __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); |
| __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); |
| preempt_enable(); |
| } |
| mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages); |
| if (uncharge) |
| /* This is not "cancel", but cancel_charge does all we need. */ |
| __mem_cgroup_cancel_charge(from, nr_pages); |
| |
| /* caller should have done css_get */ |
| pc->mem_cgroup = to; |
| mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages); |
| /* |
| * We charges against "to" which may not have any tasks. Then, "to" |
| * can be under rmdir(). But in current implementation, caller of |
| * this function is just force_empty() and move charge, so it's |
| * guaranteed that "to" is never removed. So, we don't check rmdir |
| * status here. |
| */ |
| move_unlock_page_cgroup(pc, &flags); |
| ret = 0; |
| unlock: |
| unlock_page_cgroup(pc); |
| /* |
| * check events |
| */ |
| memcg_check_events(to, page); |
| memcg_check_events(from, page); |
| out: |
| return ret; |
| } |
| |
| /* |
| * move charges to its parent. |
| */ |
| |
| static int mem_cgroup_move_parent(struct page *page, |
| struct page_cgroup *pc, |
| struct mem_cgroup *child, |
| gfp_t gfp_mask) |
| { |
| struct cgroup *cg = child->css.cgroup; |
| struct cgroup *pcg = cg->parent; |
| struct mem_cgroup *parent; |
| unsigned int nr_pages; |
| unsigned long uninitialized_var(flags); |
| int ret; |
| |
| /* Is ROOT ? */ |
| if (!pcg) |
| return -EINVAL; |
| |
| ret = -EBUSY; |
| if (!get_page_unless_zero(page)) |
| goto out; |
| if (isolate_lru_page(page)) |
| goto put; |
| |
| nr_pages = hpage_nr_pages(page); |
| |
| parent = mem_cgroup_from_cont(pcg); |
| ret = __mem_cgroup_try_charge(NULL, gfp_mask, nr_pages, &parent, false); |
| if (ret) |
| goto put_back; |
| |
| if (nr_pages > 1) |
| flags = compound_lock_irqsave(page); |
| |
| ret = mem_cgroup_move_account(page, nr_pages, pc, child, parent, true); |
| if (ret) |
| __mem_cgroup_cancel_charge(parent, nr_pages); |
| |
| if (nr_pages > 1) |
| compound_unlock_irqrestore(page, flags); |
| put_back: |
| putback_lru_page(page); |
| put: |
| put_page(page); |
| out: |
| return ret; |
| } |
| |
| /* |
| * Charge the memory controller for page usage. |
| * Return |
| * 0 if the charge was successful |
| * < 0 if the cgroup is over its limit |
| */ |
| static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, |
| gfp_t gfp_mask, enum charge_type ctype) |
| { |
| struct mem_cgroup *memcg = NULL; |
| unsigned int nr_pages = 1; |
| struct page_cgroup *pc; |
| bool oom = true; |
| int ret; |
| |
| if (PageTransHuge(page)) { |
| nr_pages <<= compound_order(page); |
| VM_BUG_ON(!PageTransHuge(page)); |
| /* |
| * Never OOM-kill a process for a huge page. The |
| * fault handler will fall back to regular pages. |
| */ |
| oom = false; |
| } |
| |
| pc = lookup_page_cgroup(page); |
| ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &memcg, oom); |
| if (ret == -ENOMEM) |
| return ret; |
| __mem_cgroup_commit_charge(memcg, page, nr_pages, pc, ctype, false); |
| return 0; |
| } |
| |
| int mem_cgroup_newpage_charge(struct page *page, |
| struct mm_struct *mm, gfp_t gfp_mask) |
| { |
| if (mem_cgroup_disabled()) |
| return 0; |
| VM_BUG_ON(page_mapped(page)); |
| VM_BUG_ON(page->mapping && !PageAnon(page)); |
| VM_BUG_ON(!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) |
| { |
| struct mem_cgroup *memcg = NULL; |
| enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE; |
| int ret; |
| |
| if (mem_cgroup_disabled()) |
| return 0; |
| if (PageCompound(page)) |
| return 0; |
| |
| if (unlikely(!mm)) |
| mm = &init_mm; |
| if (!page_is_file_cache(page)) |
| type = MEM_CGROUP_CHARGE_TYPE_SHMEM; |
| |
| if (!PageSwapCache(page)) |
| ret = mem_cgroup_charge_common(page, mm, gfp_mask, type); |
| else { /* page is swapcache/shmem */ |
| ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &memcg); |
| if (!ret) |
| __mem_cgroup_commit_charge_swapin(page, memcg, type); |
| } |
| 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 **memcgp) |
| { |
| struct mem_cgroup *memcg; |
| int ret; |
| |
| *memcgp = NULL; |
| |
| if (mem_cgroup_disabled()) |
| return 0; |
| |
| if (!do_swap_account) |
| goto charge_cur_mm; |
| /* |
| * A racing thread's fault, or swapoff, may have already updated |
| * the pte, and even removed page from swap cache: in those cases |
| * do_swap_page()'s pte_same() test will fail; but there's also a |
| * KSM case which does need to charge the page. |
| */ |
| if (!PageSwapCache(page)) |
| goto charge_cur_mm; |
| memcg = try_get_mem_cgroup_from_page(page); |
| if (!memcg) |
| goto charge_cur_mm; |
| *memcgp = memcg; |
| ret = __mem_cgroup_try_charge(NULL, mask, 1, memcgp, true); |
| css_put(&memcg->css); |
| if (ret == -EINTR) |
| ret = 0; |
| return ret; |
| charge_cur_mm: |
| if (unlikely(!mm)) |
| mm = &init_mm; |
| ret = __mem_cgroup_try_charge(mm, mask, 1, memcgp, true); |
| if (ret == -EINTR) |
| ret = 0; |
| return ret; |
| } |
| |
| static void |
| __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg, |
| enum charge_type ctype) |
| { |
| struct page_cgroup *pc; |
| |
| if (mem_cgroup_disabled()) |
| return; |
| if (!memcg) |
| return; |
| cgroup_exclude_rmdir(&memcg->css); |
| |
| pc = lookup_page_cgroup(page); |
| __mem_cgroup_commit_charge(memcg, page, 1, pc, ctype, true); |
| /* |
| * 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)}; |
| struct mem_cgroup *swap_memcg; |
| unsigned short id; |
| |
| id = swap_cgroup_record(ent, 0); |
| rcu_read_lock(); |
| swap_memcg = mem_cgroup_lookup(id); |
| if (swap_memcg) { |
| /* |
| * This recorded memcg can be obsolete one. So, avoid |
| * calling css_tryget |
| */ |
| if (!mem_cgroup_is_root(swap_memcg)) |
| res_counter_uncharge(&swap_memcg->memsw, |
| PAGE_SIZE); |
| mem_cgroup_swap_statistics(swap_memcg, false); |
| mem_cgroup_put(swap_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(&memcg->css); |
| } |
| |
| void mem_cgroup_commit_charge_swapin(struct page *page, |
| struct mem_cgroup *memcg) |
| { |
| __mem_cgroup_commit_charge_swapin(page, memcg, |
| MEM_CGROUP_CHARGE_TYPE_MAPPED); |
| } |
| |
| void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg) |
| { |
| if (mem_cgroup_disabled()) |
| return; |
| if (!memcg) |
| return; |
| __mem_cgroup_cancel_charge(memcg, 1); |
| } |
| |
| static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg, |
| unsigned int nr_pages, |
| const enum charge_type ctype) |
| { |
| struct memcg_batch_info *batch = NULL; |
| bool uncharge_memsw = true; |
| |
| /* If swapout, usage of swap doesn't decrease */ |
| if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) |
| uncharge_memsw = false; |
| |
| batch = ¤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 = memcg; |
| /* |
| * do_batch > 0 when unmapping pages or inode invalidate/truncate. |
| * In those cases, all pages freed continuously can be expected to be in |
| * the same cgroup and we have chance to coalesce uncharges. |
| * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE) |
| * because we want to do uncharge as soon as possible. |
| */ |
| |
| if (!batch->do_batch || test_thread_flag(TIF_MEMDIE)) |
| goto direct_uncharge; |
| |
| if (nr_pages > 1) |
| goto direct_uncharge; |
| |
| /* |
| * In typical case, batch->memcg == mem. This means we can |
| * merge a series of uncharges to an uncharge of res_counter. |
| * If not, we uncharge res_counter ony by one. |
| */ |
| if (batch->memcg != memcg) |
| goto direct_uncharge; |
| /* remember freed charge and uncharge it later */ |
| batch->nr_pages++; |
| if (uncharge_memsw) |
| batch->memsw_nr_pages++; |
| return; |
| direct_uncharge: |
| res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE); |
| if (uncharge_memsw) |
| res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE); |
| if (unlikely(batch->memcg != memcg)) |
| memcg_oom_recover(memcg); |
| return; |
| } |
| |
| /* |
| * uncharge if !page_mapped(page) |
| */ |
| static struct mem_cgroup * |
| __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype) |
| { |
| struct mem_cgroup *memcg = NULL; |
| unsigned int nr_pages = 1; |
| struct page_cgroup *pc; |
| |
| if (mem_cgroup_disabled()) |
| return NULL; |
| |
| if (PageSwapCache(page)) |
| return NULL; |
| |
| if (PageTransHuge(page)) { |
| nr_pages <<= compound_order(page); |
| VM_BUG_ON(!PageTransHuge(page)); |
| } |
| /* |
| * Check if our page_cgroup is valid |
| */ |
| pc = lookup_page_cgroup(page); |
| if (unlikely(!PageCgroupUsed(pc))) |
| return NULL; |
| |
| lock_page_cgroup(pc); |
| |
| memcg = 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(memcg, PageCgroupCache(pc), -nr_pages); |
| |
| ClearPageCgroupUsed(pc); |
| /* |
| * pc->mem_cgroup is not cleared here. It will be accessed when it's |
| * freed from LRU. This is safe because uncharged page is expected not |
| * to be reused (freed soon). Exception is SwapCache, it's handled by |
| * special functions. |
| */ |
| |
| unlock_page_cgroup(pc); |
| /* |
| * even after unlock, we have memcg->res.usage here and this memcg |
| * will never be freed. |
| */ |
| memcg_check_events(memcg, page); |
| if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) { |
| mem_cgroup_swap_statistics(memcg, true); |
| mem_cgroup_get(memcg); |
| } |
| if (!mem_cgroup_is_root(memcg)) |
| mem_cgroup_do_uncharge(memcg, nr_pages, ctype); |
| |
| return memcg; |
| |
| unlock_out: |
| unlock_page_cgroup(pc); |
| return NULL; |
| } |
| |
| void mem_cgroup_uncharge_page(struct page *page) |
| { |
| /* early check. */ |
| if (page_mapped(page)) |
| return; |
| VM_BUG_ON(page->mapping && !PageAnon(page)); |
| __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED); |
| } |
| |
| void mem_cgroup_uncharge_cache_page(struct page *page) |
| { |
| VM_BUG_ON(page_mapped(page)); |
| VM_BUG_ON(page->mapping); |
| __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE); |
| } |
| |
| /* |
| * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate. |
| * In that cases, pages are freed continuously and we can expect pages |
| * are in the same memcg. All these calls itself limits the number of |
| * pages freed at once, then uncharge_start/end() is called properly. |
| * This may be called prural(2) times in a context, |
| */ |
| |
| void mem_cgroup_uncharge_start(void) |
| { |
| current->memcg_batch.do_batch++; |
| /* We can do nest. */ |
| if (current->memcg_batch.do_batch == 1) { |
| current->memcg_batch.memcg = NULL; |
| current->memcg_batch.nr_pages = 0; |
| current->memcg_batch.memsw_nr_pages = 0; |
| } |
| } |
| |
| void mem_cgroup_uncharge_end(void) |
| { |
| struct memcg_batch_info *batch = ¤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->nr_pages) |
| res_counter_uncharge(&batch->memcg->res, |
| batch->nr_pages * PAGE_SIZE); |
| if (batch->memsw_nr_pages) |
| res_counter_uncharge(&batch->memcg->memsw, |
| batch->memsw_nr_pages * PAGE_SIZE); |
| memcg_oom_recover(batch->memcg); |
| /* forget this pointer (for sanity check) */ |
| batch->memcg = NULL; |
| } |
| |
| #ifdef CONFIG_SWAP |
| /* |
| * called after __delete_from_swap_cache() and drop "page" account. |
| * memcg information is recorded to swap_cgroup of "ent" |
| */ |
| void |
| mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) |
| { |
| struct mem_cgroup *memcg; |
| int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT; |
| |
| if (!swapout) /* this was a swap cache but the swap is unused ! */ |
| ctype = MEM_CGROUP_CHARGE_TYPE_DROP; |
| |
| memcg = __mem_cgroup_uncharge_common(page, ctype); |
| |
| /* |
| * record memcg information, if swapout && memcg != NULL, |
| * mem_cgroup_get() was called in uncharge(). |
| */ |
| if (do_swap_account && swapout && memcg) |
| swap_cgroup_record(ent, css_id(&memcg->css)); |
| } |
| #endif |
| |
| #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP |
| /* |
| * called from swap_entry_free(). remove record in swap_cgroup and |
| * uncharge "memsw" account. |
| */ |
| void mem_cgroup_uncharge_swap(swp_entry_t ent) |
| { |
| struct mem_cgroup *memcg; |
| unsigned short id; |
| |
| if (!do_swap_account) |
| return; |
| |
| id = swap_cgroup_record(ent, 0); |
| rcu_read_lock(); |
| memcg = mem_cgroup_lookup(id); |
| if (memcg) { |
| /* |
| * We uncharge this because swap is freed. |
| * This memcg can be obsolete one. We avoid calling css_tryget |
| */ |
| if (!mem_cgroup_is_root(memcg)) |
| res_counter_uncharge(&memcg->memsw, PAGE_SIZE); |
| mem_cgroup_swap_statistics(memcg, false); |
| mem_cgroup_put(memcg); |
| } |
| rcu_read_unlock(); |
| } |
| |
| /** |
| * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record. |
| * @entry: swap entry to be moved |
| * @from: mem_cgroup which the entry is moved from |
| * @to: mem_cgroup which the entry is moved to |
| * @need_fixup: whether we should fixup res_counters and refcounts. |
| * |
| * It succeeds only when the swap_cgroup's record for this entry is the same |
| * as the mem_cgroup's id of @from. |
| * |
| * Returns 0 on success, -EINVAL on failure. |
| * |
| * The caller must have charged to @to, IOW, called res_counter_charge() about |
| * both res and memsw, and called css_get(). |
| */ |
| static int mem_cgroup_move_swap_account(swp_entry_t entry, |
| struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup) |
| { |
| unsigned short old_id, new_id; |
| |
| old_id = css_id(&from->css); |
| new_id = css_id(&to->css); |
| |
| if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { |
| mem_cgroup_swap_statistics(from, false); |
| mem_cgroup_swap_statistics(to, true); |
| /* |
| * This function is only called from task migration context now. |
| * It postpones res_counter and refcount handling till the end |
| * of task migration(mem_cgroup_clear_mc()) for performance |
| * improvement. But we cannot postpone mem_cgroup_get(to) |
| * because if the process that has been moved to @to does |
| * swap-in, the refcount of @to might be decreased to 0. |
| */ |
| mem_cgroup_get(to); |
| if (need_fixup) { |
| if (!mem_cgroup_is_root(from)) |
| res_counter_uncharge(&from->memsw, PAGE_SIZE); |
| mem_cgroup_put(from); |
| /* |
| * we charged both to->res and to->memsw, so we should |
| * uncharge to->res. |
| */ |
| if (!mem_cgroup_is_root(to)) |
| res_counter_uncharge(&to->res, PAGE_SIZE); |
| } |
| return 0; |
| } |
| return -EINVAL; |
| } |
| #else |
| static inline int mem_cgroup_move_swap_account(swp_entry_t entry, |
| struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup) |
| { |
| return -EINVAL; |
| } |
| #endif |
| |
| /* |
| * Before starting migration, account PAGE_SIZE to mem_cgroup that the old |
| * page belongs to. |
| */ |
| int mem_cgroup_prepare_migration(struct page *page, |
| struct page *newpage, struct mem_cgroup **memcgp, gfp_t gfp_mask) |
| { |
| struct mem_cgroup *memcg = NULL; |
| struct page_cgroup *pc; |
| enum charge_type ctype; |
| int ret = 0; |
| |
| *memcgp = NULL; |
| |
| VM_BUG_ON(PageTransHuge(page)); |
| if (mem_cgroup_disabled()) |
| return 0; |
| |
| pc = lookup_page_cgroup(page); |
| lock_page_cgroup(pc); |
| if (PageCgroupUsed(pc)) { |
| memcg = pc->mem_cgroup; |
| css_get(&memcg->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 (!memcg) |
| return 0; |
| |
| *memcgp = memcg; |
| ret = __mem_cgroup_try_charge(NULL, gfp_mask, 1, memcgp, false); |
| css_put(&memcg->css);/* drop extra refcnt */ |
| if (ret) { |
| 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); |
| } |
| /* we'll need to revisit this error code (we have -EINTR) */ |
| 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(memcg, newpage, 1, pc, ctype, false); |
| return ret; |
| } |
| |
| /* remove redundant charge if migration failed*/ |
| void mem_cgroup_end_migration(struct mem_cgroup *memcg, |
| struct page *oldpage, struct page *newpage, bool migration_ok) |
| { |
| struct page *used, *unused; |
| struct page_cgroup *pc; |
| |
| if (!memcg) |
| return; |
| /* blocks rmdir() */ |
| cgroup_exclude_rmdir(&memcg->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(&memcg->css); |
| } |
| |
| /* |
| * At replace page cache, newpage is not under any memcg but it's on |
| * LRU. So, this function doesn't touch res_counter but handles LRU |
| * in correct way. Both pages are locked so we cannot race with uncharge. |
| */ |
| void mem_cgroup_replace_page_cache(struct page *oldpage, |
| struct page *newpage) |
| { |
| struct mem_cgroup *memcg; |
| struct page_cgroup *pc; |
| enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE; |
| |
| if (mem_cgroup_disabled()) |
| return; |
| |
| pc = lookup_page_cgroup(oldpage); |
| /* fix accounting on old pages */ |
| lock_page_cgroup(pc); |
| memcg = pc->mem_cgroup; |
| mem_cgroup_charge_statistics(memcg, PageCgroupCache(pc), -1); |
| ClearPageCgroupUsed(pc); |
| unlock_pa
|