diff options
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 2866 |
1 files changed, 1467 insertions, 1399 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 194721839cf..1f14a430c65 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -45,26 +45,29 @@ #include <linux/swapops.h> #include <linux/spinlock.h> #include <linux/eventfd.h> +#include <linux/poll.h> #include <linux/sort.h> #include <linux/fs.h> #include <linux/seq_file.h> -#include <linux/vmalloc.h> #include <linux/vmpressure.h> #include <linux/mm_inline.h> #include <linux/page_cgroup.h> #include <linux/cpu.h> #include <linux/oom.h> +#include <linux/lockdep.h> +#include <linux/file.h> #include "internal.h" #include <net/sock.h> #include <net/ip.h> #include <net/tcp_memcontrol.h> +#include "slab.h" #include <asm/uaccess.h> #include <trace/events/vmscan.h> -struct cgroup_subsys mem_cgroup_subsys __read_mostly; -EXPORT_SYMBOL(mem_cgroup_subsys); +struct cgroup_subsys memory_cgrp_subsys __read_mostly; +EXPORT_SYMBOL(memory_cgrp_subsys); #define MEM_CGROUP_RECLAIM_RETRIES 5 static struct mem_cgroup *root_mem_cgroup __read_mostly; @@ -77,7 +80,7 @@ int do_swap_account __read_mostly; #ifdef CONFIG_MEMCG_SWAP_ENABLED static int really_do_swap_account __initdata = 1; #else -static int really_do_swap_account __initdata = 0; +static int really_do_swap_account __initdata; #endif #else @@ -85,26 +88,12 @@ static int really_do_swap_account __initdata = 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_RSS_HUGE, /* # of pages charged as anon huge */ - MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */ - MEM_CGROUP_STAT_SWAP, /* # of pages, swapped out */ - MEM_CGROUP_STAT_NSTATS, -}; - static const char * const mem_cgroup_stat_names[] = { "cache", "rss", "rss_huge", "mapped_file", + "writeback", "swap", }; @@ -160,7 +149,7 @@ struct mem_cgroup_reclaim_iter { * matches memcg->dead_count of the hierarchy root group. */ struct mem_cgroup *last_visited; - unsigned long last_dead_count; + int last_dead_count; /* scan generation, increased every round-trip */ unsigned int generation; @@ -187,10 +176,6 @@ 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[0]; -}; - /* * Cgroups above their limits are maintained in a RB-Tree, independent of * their hierarchy representation @@ -243,6 +228,46 @@ struct mem_cgroup_eventfd_list { struct eventfd_ctx *eventfd; }; +/* + * cgroup_event represents events which userspace want to receive. + */ +struct mem_cgroup_event { + /* + * memcg which the event belongs to. + */ + struct mem_cgroup *memcg; + /* + * eventfd to signal userspace about the event. + */ + struct eventfd_ctx *eventfd; + /* + * Each of these stored in a list by the cgroup. + */ + struct list_head list; + /* + * register_event() callback will be used to add new userspace + * waiter for changes related to this event. Use eventfd_signal() + * on eventfd to send notification to userspace. + */ + int (*register_event)(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd, const char *args); + /* + * unregister_event() callback will be called when userspace closes + * the eventfd or on cgroup removing. This callback must be set, + * if you want provide notification functionality. + */ + void (*unregister_event)(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd); + /* + * All fields below needed to unregister event when + * userspace closes eventfd. + */ + poll_table pt; + wait_queue_head_t *wqh; + wait_queue_t wait; + struct work_struct remove; +}; + static void mem_cgroup_threshold(struct mem_cgroup *memcg); static void mem_cgroup_oom_notify(struct mem_cgroup *memcg); @@ -267,28 +292,10 @@ struct mem_cgroup { /* vmpressure notifications */ struct vmpressure vmpressure; - 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; - /* - * We also need some space for a worker in deferred freeing. - * By the time we call it, rcu_freeing is no longer in use. - */ - struct work_struct work_freeing; - }; + /* + * the counter to account for mem+swap usage. + */ + struct res_counter memsw; /* * the counter to account for kernel memory usage. @@ -302,8 +309,7 @@ struct mem_cgroup { bool oom_lock; atomic_t under_oom; - - atomic_t refcnt; + atomic_t oom_wakeups; int swappiness; /* OOM-Killer disable */ @@ -328,7 +334,7 @@ struct mem_cgroup { * 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; + unsigned long move_charge_at_immigrate; /* * set > 0 if pages under this cgroup are moving to other cgroup. */ @@ -348,13 +354,12 @@ struct mem_cgroup { atomic_t dead_count; #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET) - struct tcp_memcontrol tcp_mem; + struct cg_proto tcp_mem; #endif #if defined(CONFIG_MEMCG_KMEM) - /* analogous to slab_common's slab_caches list. per-memcg */ + /* analogous to slab_common's slab_caches list, but per-memcg; + * protected by memcg_slab_mutex */ struct list_head memcg_slab_caches; - /* Not a spinlock, we can take a lot of time walking the list */ - struct mutex slab_caches_mutex; /* Index in the kmem_cache->memcg_params->memcg_caches array */ int kmemcg_id; #endif @@ -366,33 +371,20 @@ struct mem_cgroup { atomic_t numainfo_updating; #endif - /* - * Per cgroup active and inactive list, similar to the - * per zone LRU lists. - * - * WARNING: This has to be the last element of the struct. Don't - * add new fields after this point. - */ - struct mem_cgroup_lru_info info; -}; + /* List of events which userspace want to receive */ + struct list_head event_list; + spinlock_t event_list_lock; -static size_t memcg_size(void) -{ - return sizeof(struct mem_cgroup) + - nr_node_ids * sizeof(struct mem_cgroup_per_node); -} + struct mem_cgroup_per_node *nodeinfo[0]; + /* WARNING: nodeinfo must be the last member here */ +}; /* internal only representation about the status of kmem accounting. */ enum { - KMEM_ACCOUNTED_ACTIVE = 0, /* accounted by this cgroup itself */ - KMEM_ACCOUNTED_ACTIVATED, /* static key enabled. */ + KMEM_ACCOUNTED_ACTIVE, /* accounted by this cgroup itself */ KMEM_ACCOUNTED_DEAD, /* dead memcg with pending kmem charges */ }; -/* We account when limit is on, but only after call sites are patched */ -#define KMEM_ACCOUNTED_MASK \ - ((1 << KMEM_ACCOUNTED_ACTIVE) | (1 << KMEM_ACCOUNTED_ACTIVATED)) - #ifdef CONFIG_MEMCG_KMEM static inline void memcg_kmem_set_active(struct mem_cgroup *memcg) { @@ -404,18 +396,13 @@ static bool memcg_kmem_is_active(struct mem_cgroup *memcg) return test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags); } -static void memcg_kmem_set_activated(struct mem_cgroup *memcg) -{ - set_bit(KMEM_ACCOUNTED_ACTIVATED, &memcg->kmem_account_flags); -} - -static void memcg_kmem_clear_activated(struct mem_cgroup *memcg) -{ - clear_bit(KMEM_ACCOUNTED_ACTIVATED, &memcg->kmem_account_flags); -} - static void memcg_kmem_mark_dead(struct mem_cgroup *memcg) { + /* + * Our caller must use css_get() first, because memcg_uncharge_kmem() + * will call css_put() if it sees the memcg is dead. + */ + smp_wmb(); if (test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags)) set_bit(KMEM_ACCOUNTED_DEAD, &memcg->kmem_account_flags); } @@ -508,13 +495,9 @@ enum res_type { */ static DEFINE_MUTEX(memcg_create_mutex); -static void mem_cgroup_get(struct mem_cgroup *memcg); -static void mem_cgroup_put(struct mem_cgroup *memcg); - -static inline struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s) { - return container_of(s, struct mem_cgroup, css); + return s ? container_of(s, struct mem_cgroup, css) : NULL; } /* Some nice accessors for the vmpressure. */ @@ -530,14 +513,28 @@ struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr) return &container_of(vmpr, struct mem_cgroup, vmpressure)->css; } -struct vmpressure *css_to_vmpressure(struct cgroup_subsys_state *css) +static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg) { - return &mem_cgroup_from_css(css)->vmpressure; + return (memcg == root_mem_cgroup); } -static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg) +/* + * We restrict the id in the range of [1, 65535], so it can fit into + * an unsigned short. + */ +#define MEM_CGROUP_ID_MAX USHRT_MAX + +static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg) { - return (memcg == root_mem_cgroup); + return memcg->css.id; +} + +static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id) +{ + struct cgroup_subsys_state *css; + + css = css_from_id(id, &memory_cgrp_subsys); + return mem_cgroup_from_css(css); } /* Writing them here to avoid exposing memcg's inner layout */ @@ -561,15 +558,16 @@ void sock_update_memcg(struct sock *sk) */ if (sk->sk_cgrp) { BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg)); - mem_cgroup_get(sk->sk_cgrp->memcg); + css_get(&sk->sk_cgrp->memcg->css); return; } rcu_read_lock(); memcg = mem_cgroup_from_task(current); cg_proto = sk->sk_prot->proto_cgroup(memcg); - if (!mem_cgroup_is_root(memcg) && memcg_proto_active(cg_proto)) { - mem_cgroup_get(memcg); + if (!mem_cgroup_is_root(memcg) && + memcg_proto_active(cg_proto) && + css_tryget_online(&memcg->css)) { sk->sk_cgrp = cg_proto; } rcu_read_unlock(); @@ -583,7 +581,7 @@ void sock_release_memcg(struct sock *sk) struct mem_cgroup *memcg; WARN_ON(!sk->sk_cgrp->memcg); memcg = sk->sk_cgrp->memcg; - mem_cgroup_put(memcg); + css_put(&sk->sk_cgrp->memcg->css); } } @@ -592,13 +590,13 @@ 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; + return &memcg->tcp_mem; } EXPORT_SYMBOL(tcp_proto_cgroup); static void disarm_sock_keys(struct mem_cgroup *memcg) { - if (!memcg_proto_activated(&memcg->tcp_mem.cg_proto)) + if (!memcg_proto_activated(&memcg->tcp_mem)) return; static_key_slow_dec(&memcg_socket_limit_enabled); } @@ -611,16 +609,11 @@ static void disarm_sock_keys(struct mem_cgroup *memcg) #ifdef CONFIG_MEMCG_KMEM /* * This will be the memcg's index in each cache's ->memcg_params->memcg_caches. - * There are two main reasons for not using the css_id for this: - * 1) this works better in sparse environments, where we have a lot of memcgs, - * but only a few kmem-limited. Or also, if we have, for instance, 200 - * memcgs, and none but the 200th is kmem-limited, we'd have to have a - * 200 entry array for that. - * - * 2) In order not to violate the cgroup API, we would like to do all memory - * allocation in ->create(). At that point, we haven't yet allocated the - * css_id. Having a separate index prevents us from messing with the cgroup - * core for this + * The main reason for not using cgroup id for this: + * this works better in sparse environments, where we have a lot of memcgs, + * but only a few kmem-limited. Or also, if we have, for instance, 200 + * memcgs, and none but the 200th is kmem-limited, we'd have to have a + * 200 entry array for that. * * The current size of the caches array is stored in * memcg_limited_groups_array_size. It will double each time we have to @@ -635,14 +628,14 @@ int memcg_limited_groups_array_size; * cgroups is a reasonable guess. In the future, it could be a parameter or * tunable, but that is strictly not necessary. * - * MAX_SIZE should be as large as the number of css_ids. Ideally, we could get + * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get * this constant directly from cgroup, but it is understandable that this is * better kept as an internal representation in cgroup.c. In any case, the - * css_id space is not getting any smaller, and we don't have to necessarily + * cgrp_id space is not getting any smaller, and we don't have to necessarily * increase ours as well if it increases. */ #define MEMCG_CACHES_MIN_SIZE 4 -#define MEMCG_CACHES_MAX_SIZE 65535 +#define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX /* * A lot of the calls to the cache allocation functions are expected to be @@ -680,10 +673,12 @@ static void disarm_static_keys(struct mem_cgroup *memcg) 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) +mem_cgroup_zone_zoneinfo(struct mem_cgroup *memcg, struct zone *zone) { - VM_BUG_ON((unsigned)nid >= nr_node_ids); - return &memcg->info.nodeinfo[nid]->zoneinfo[zid]; + int nid = zone_to_nid(zone); + int zid = zone_idx(zone); + + return &memcg->nodeinfo[nid]->zoneinfo[zid]; } struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg) @@ -692,12 +687,12 @@ struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg) } static struct mem_cgroup_per_zone * -page_cgroup_zoneinfo(struct mem_cgroup *memcg, struct page *page) +mem_cgroup_page_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); + return &memcg->nodeinfo[nid]->zoneinfo[zid]; } static struct mem_cgroup_tree_per_zone * @@ -715,11 +710,9 @@ soft_limit_tree_from_page(struct page *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) +static void __mem_cgroup_insert_exceeded(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; @@ -749,10 +742,8 @@ __mem_cgroup_insert_exceeded(struct mem_cgroup *memcg, 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) +static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz, + struct mem_cgroup_tree_per_zone *mctz) { if (!mz->on_tree) return; @@ -760,13 +751,11 @@ __mem_cgroup_remove_exceeded(struct mem_cgroup *memcg, 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) +static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz, + struct mem_cgroup_tree_per_zone *mctz) { spin_lock(&mctz->lock); - __mem_cgroup_remove_exceeded(memcg, mz, mctz); + __mem_cgroup_remove_exceeded(mz, mctz); spin_unlock(&mctz->lock); } @@ -776,16 +765,14 @@ 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); + 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); + mz = mem_cgroup_page_zoneinfo(memcg, page); excess = res_counter_soft_limit_excess(&memcg->res); /* * We have to update the tree if mz is on RB-tree or @@ -795,12 +782,12 @@ static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page) spin_lock(&mctz->lock); /* if on-tree, remove it */ if (mz->on_tree) - __mem_cgroup_remove_exceeded(memcg, mz, mctz); + __mem_cgroup_remove_exceeded(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); + __mem_cgroup_insert_exceeded(mz, mctz, excess); spin_unlock(&mctz->lock); } } @@ -808,15 +795,15 @@ static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page) 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; + struct mem_cgroup_per_zone *mz; + int nid, zid; - 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); + for_each_node(nid) { + for (zid = 0; zid < MAX_NR_ZONES; zid++) { + mz = &memcg->nodeinfo[nid]->zoneinfo[zid]; + mctz = soft_limit_tree_node_zone(nid, zid); + mem_cgroup_remove_exceeded(mz, mctz); } } } @@ -839,9 +826,9 @@ retry: * we will to add it back at the end of reclaim to its correct * position in the tree. */ - __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz); + __mem_cgroup_remove_exceeded(mz, mctz); if (!res_counter_soft_limit_excess(&mz->memcg->res) || - !css_tryget(&mz->memcg->css)) + !css_tryget_online(&mz->memcg->css)) goto retry; done: return mz; @@ -908,6 +895,7 @@ static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg, unsigned long val = 0; int cpu; + get_online_cpus(); for_each_online_cpu(cpu) val += per_cpu(memcg->stat->events[idx], cpu); #ifdef CONFIG_HOTPLUG_CPU @@ -915,6 +903,7 @@ static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg, val += memcg->nocpu_base.events[idx]; spin_unlock(&memcg->pcp_counter_lock); #endif + put_online_cpus(); return val; } @@ -922,8 +911,6 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, struct page *page, bool anon, int nr_pages) { - preempt_disable(); - /* * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is * counted as CACHE even if it's on ANON LRU. @@ -948,12 +935,9 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, } __this_cpu_add(memcg->stat->nr_page_events, nr_pages); - - preempt_enable(); } -unsigned long -mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru) +unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru) { struct mem_cgroup_per_zone *mz; @@ -961,46 +945,38 @@ mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru) return mz->lru_size[lru]; } -static 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 lru; - unsigned long ret = 0; - - mz = mem_cgroup_zoneinfo(memcg, nid, zid); - - for_each_lru(lru) { - if (BIT(lru) & lru_mask) - ret += mz->lru_size[lru]; - } - return ret; -} - -static unsigned long -mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg, - int nid, unsigned int lru_mask) +static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg, + int nid, + unsigned int lru_mask) { - u64 total = 0; + unsigned long nr = 0; int zid; - for (zid = 0; zid < MAX_NR_ZONES; zid++) - total += mem_cgroup_zone_nr_lru_pages(memcg, - nid, zid, lru_mask); + VM_BUG_ON((unsigned)nid >= nr_node_ids); - return total; + for (zid = 0; zid < MAX_NR_ZONES; zid++) { + struct mem_cgroup_per_zone *mz; + enum lru_list lru; + + for_each_lru(lru) { + if (!(BIT(lru) & lru_mask)) + continue; + mz = &memcg->nodeinfo[nid]->zoneinfo[zid]; + nr += mz->lru_size[lru]; + } + } + return nr; } static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg, unsigned int lru_mask) { + unsigned long nr = 0; int nid; - u64 total = 0; for_each_node_state(nid, N_MEMORY) - total += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask); - return total; + nr += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask); + return nr; } static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, @@ -1063,12 +1039,6 @@ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) preempt_enable(); } -struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) -{ - return mem_cgroup_from_css( - cgroup_subsys_state(cont, mem_cgroup_subsys_id)); -} - struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) { /* @@ -1079,26 +1049,28 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) if (unlikely(!p)) return NULL; - return mem_cgroup_from_css(task_subsys_state(p, mem_cgroup_subsys_id)); + return mem_cgroup_from_css(task_css(p, memory_cgrp_id)); } -struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) +static struct mem_cgroup *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)); + /* + * Page cache insertions can happen withou an + * actual mm context, e.g. during disk probing + * on boot, loopback IO, acct() writes etc. + */ + if (unlikely(!mm)) + memcg = root_mem_cgroup; + else { + memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); + if (unlikely(!memcg)) + memcg = root_mem_cgroup; + } + } while (!css_tryget_online(&memcg->css)); rcu_read_unlock(); return memcg; } @@ -1112,20 +1084,11 @@ struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) static struct mem_cgroup *__mem_cgroup_iter_next(struct mem_cgroup *root, struct mem_cgroup *last_visited) { - struct cgroup *prev_cgroup, *next_cgroup; + struct cgroup_subsys_state *prev_css, *next_css; - /* - * Root is not visited by cgroup iterators so it needs an - * explicit visit. - */ - if (!last_visited) - return root; - - prev_cgroup = (last_visited == root) ? NULL - : last_visited->css.cgroup; + prev_css = last_visited ? &last_visited->css : NULL; skip_node: - next_cgroup = cgroup_next_descendant_pre( - prev_cgroup, root->css.cgroup); + next_css = css_next_descendant_pre(prev_css, &root->css); /* * Even if we found a group we have to make sure it is @@ -1133,21 +1096,90 @@ skip_node: * skipped and we should continue the tree walk. * last_visited css is safe to use because it is * protected by css_get and the tree walk is rcu safe. + * + * We do not take a reference on the root of the tree walk + * because we might race with the root removal when it would + * be the only node in the iterated hierarchy and mem_cgroup_iter + * would end up in an endless loop because it expects that at + * least one valid node will be returned. Root cannot disappear + * because caller of the iterator should hold it already so + * skipping css reference should be safe. */ - if (next_cgroup) { - struct mem_cgroup *mem = mem_cgroup_from_cont( - next_cgroup); - if (css_tryget(&mem->css)) - return mem; - else { - prev_cgroup = next_cgroup; - goto skip_node; - } + if (next_css) { + if ((next_css == &root->css) || + ((next_css->flags & CSS_ONLINE) && + css_tryget_online(next_css))) + return mem_cgroup_from_css(next_css); + + prev_css = next_css; + goto skip_node; } return NULL; } +static void mem_cgroup_iter_invalidate(struct mem_cgroup *root) +{ + /* + * When a group in the hierarchy below root is destroyed, the + * hierarchy iterator can no longer be trusted since it might + * have pointed to the destroyed group. Invalidate it. + */ + atomic_inc(&root->dead_count); +} + +static struct mem_cgroup * +mem_cgroup_iter_load(struct mem_cgroup_reclaim_iter *iter, + struct mem_cgroup *root, + int *sequence) +{ + struct mem_cgroup *position = NULL; + /* + * A cgroup destruction happens in two stages: offlining and + * release. They are separated by a RCU grace period. + * + * If the iterator is valid, we may still race with an + * offlining. The RCU lock ensures the object won't be + * released, tryget will fail if we lost the race. + */ + *sequence = atomic_read(&root->dead_count); + if (iter->last_dead_count == *sequence) { + smp_rmb(); + position = iter->last_visited; + + /* + * We cannot take a reference to root because we might race + * with root removal and returning NULL would end up in + * an endless loop on the iterator user level when root + * would be returned all the time. + */ + if (position && position != root && + !css_tryget_online(&position->css)) + position = NULL; + } + return position; +} + +static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter *iter, + struct mem_cgroup *last_visited, + struct mem_cgroup *new_position, + struct mem_cgroup *root, + int sequence) +{ + /* root reference counting symmetric to mem_cgroup_iter_load */ + if (last_visited && last_visited != root) + css_put(&last_visited->css); + /* + * We store the sequence count from the time @last_visited was + * loaded successfully instead of rereading it here so that we + * don't lose destruction events in between. We could have + * raced with the destruction of @new_position after all. + */ + iter->last_visited = new_position; + smp_wmb(); + iter->last_dead_count = sequence; +} + /** * mem_cgroup_iter - iterate over memory cgroup hierarchy * @root: hierarchy root @@ -1171,7 +1203,6 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, { struct mem_cgroup *memcg = NULL; struct mem_cgroup *last_visited = NULL; - unsigned long uninitialized_var(dead_count); if (mem_cgroup_disabled()) return NULL; @@ -1191,50 +1222,26 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, rcu_read_lock(); while (!memcg) { struct mem_cgroup_reclaim_iter *uninitialized_var(iter); + int uninitialized_var(seq); 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); + mz = mem_cgroup_zone_zoneinfo(root, reclaim->zone); iter = &mz->reclaim_iter[reclaim->priority]; if (prev && reclaim->generation != iter->generation) { iter->last_visited = NULL; goto out_unlock; } - /* - * If the dead_count mismatches, a destruction - * has happened or is happening concurrently. - * If the dead_count matches, a destruction - * might still happen concurrently, but since - * we checked under RCU, that destruction - * won't free the object until we release the - * RCU reader lock. Thus, the dead_count - * check verifies the pointer is still valid, - * css_tryget() verifies the cgroup pointed to - * is alive. - */ - dead_count = atomic_read(&root->dead_count); - if (dead_count == iter->last_dead_count) { - smp_rmb(); - last_visited = iter->last_visited; - if (last_visited && - !css_tryget(&last_visited->css)) - last_visited = NULL; - } + last_visited = mem_cgroup_iter_load(iter, root, &seq); } memcg = __mem_cgroup_iter_next(root, last_visited); if (reclaim) { - if (last_visited) - css_put(&last_visited->css); - - iter->last_visited = memcg; - smp_wmb(); - iter->last_dead_count = dead_count; + mem_cgroup_iter_update(iter, last_visited, memcg, root, + seq); if (!memcg) iter->generation++; @@ -1327,7 +1334,7 @@ struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone, goto out; } - mz = mem_cgroup_zoneinfo(memcg, zone_to_nid(zone), zone_idx(zone)); + mz = mem_cgroup_zone_zoneinfo(memcg, zone); lruvec = &mz->lruvec; out: /* @@ -1386,7 +1393,7 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone) if (!PageLRU(page) && !PageCgroupUsed(pc) && memcg != root_mem_cgroup) pc->mem_cgroup = memcg = root_mem_cgroup; - mz = page_cgroup_zoneinfo(memcg, page); + mz = mem_cgroup_page_zoneinfo(memcg, page); lruvec = &mz->lruvec; out: /* @@ -1434,7 +1441,7 @@ bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, return true; if (!root_memcg->use_hierarchy || !memcg) return false; - return css_is_ancestor(&memcg->css, &root_memcg->css); + return cgroup_is_descendant(memcg->css.cgroup, root_memcg->css.cgroup); } static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, @@ -1448,15 +1455,16 @@ static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, return ret; } -int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg) +bool task_in_mem_cgroup(struct task_struct *task, + const struct mem_cgroup *memcg) { - int ret; struct mem_cgroup *curr = NULL; struct task_struct *p; + bool ret; p = find_lock_task_mm(task); if (p) { - curr = try_get_mem_cgroup_from_mm(p->mm); + curr = get_mem_cgroup_from_mm(p->mm); task_unlock(p); } else { /* @@ -1464,14 +1472,12 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg) * killer still needs to detect if they have already been oom * killed to prevent needlessly killing additional tasks. */ - task_lock(task); + rcu_read_lock(); curr = mem_cgroup_from_task(task); if (curr) css_get(&curr->css); - task_unlock(task); + rcu_read_unlock(); } - 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 @@ -1524,10 +1530,8 @@ static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg) int mem_cgroup_swappiness(struct mem_cgroup *memcg) { - struct cgroup *cgrp = memcg->css.cgroup; - /* root ? */ - if (cgrp->parent == NULL) + if (mem_cgroup_disabled() || !memcg->css.parent) return vm_swappiness; return memcg->swappiness; @@ -1571,23 +1575,12 @@ static void mem_cgroup_end_move(struct mem_cgroup *memcg) } /* - * 2 routines for checking "mem" is under move_account() or not. + * A routine for checking "mem" is under move_account() or not. * - * mem_cgroup_stolen() - checking whether a cgroup is mc.from or not. This - * is used for avoiding races 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". + * Checking a cgroup is mc.from or mc.to or under hierarchy of + * moving cgroups. This is for waiting at high-memory pressure + * caused by "move". */ - -static bool mem_cgroup_stolen(struct mem_cgroup *memcg) -{ - VM_BUG_ON(!rcu_read_lock_held()); - return atomic_read(&memcg->moving_account) > 0; -} - static bool mem_cgroup_under_move(struct mem_cgroup *memcg) { struct mem_cgroup *from; @@ -1630,7 +1623,6 @@ static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg) * Take this lock when * - a code tries to modify page's memcg while it's USED. * - a code tries to modify page state accounting in a memcg. - * see mem_cgroup_stolen(), too. */ static void move_lock_mem_cgroup(struct mem_cgroup *memcg, unsigned long *flags) @@ -1655,53 +1647,25 @@ static void move_unlock_mem_cgroup(struct mem_cgroup *memcg, */ 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; + /* oom_info_lock ensures that parallel ooms do not interleave */ + static DEFINE_MUTEX(oom_info_lock); struct mem_cgroup *iter; unsigned int i; if (!p) return; + mutex_lock(&oom_info_lock); rcu_read_lock(); - mem_cgrp = memcg->css.cgroup; - task_cgrp = task_cgroup(p, mem_cgroup_subsys_id); + pr_info("Task in "); + pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id)); + pr_info(" killed as a result of limit of "); + pr_cont_cgroup_path(memcg->css.cgroup); + pr_info("\n"); - 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(); - - pr_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 - */ - pr_cont(" as a result of limit of %s\n", memcg_name); -done: - pr_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, @@ -1716,13 +1680,8 @@ done: res_counter_read_u64(&memcg->kmem, RES_FAILCNT)); for_each_mem_cgroup_tree(iter, memcg) { - pr_info("Memory cgroup stats"); - - rcu_read_lock(); - ret = cgroup_path(iter->css.cgroup, memcg_name, PATH_MAX); - if (!ret) - pr_cont(" for %s", memcg_name); - rcu_read_unlock(); + pr_info("Memory cgroup stats for "); + pr_cont_cgroup_path(iter->css.cgroup); pr_cont(":"); for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { @@ -1738,6 +1697,7 @@ done: pr_cont("\n"); } + mutex_unlock(&oom_info_lock); } /* @@ -1804,12 +1764,11 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL); totalpages = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT ? : 1; for_each_mem_cgroup_tree(iter, memcg) { - struct cgroup *cgroup = iter->css.cgroup; - struct cgroup_iter it; + struct css_task_iter it; struct task_struct *task; - cgroup_iter_start(cgroup, &it); - while ((task = cgroup_iter_next(cgroup, &it))) { + css_task_iter_start(&iter->css, &it); + while ((task = css_task_iter_next(&it))) { switch (oom_scan_process_thread(task, totalpages, NULL, false)) { case OOM_SCAN_SELECT: @@ -1822,7 +1781,7 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, case OOM_SCAN_CONTINUE: continue; case OOM_SCAN_ABORT: - cgroup_iter_end(cgroup, &it); + css_task_iter_end(&it); mem_cgroup_iter_break(memcg, iter); if (chosen) put_task_struct(chosen); @@ -1831,15 +1790,20 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, break; }; points = oom_badness(task, memcg, NULL, totalpages); - if (points > chosen_points) { - if (chosen) - put_task_struct(chosen); - chosen = task; - chosen_points = points; - get_task_struct(chosen); - } + if (!points || points < chosen_points) + continue; + /* Prefer thread group leaders for display purposes */ + if (points == chosen_points && + thread_group_leader(chosen)) + continue; + + if (chosen) + put_task_struct(chosen); + chosen = task; + chosen_points = points; + get_task_struct(chosen); } - cgroup_iter_end(cgroup, &it); + css_task_iter_end(&it); } if (!chosen) @@ -2075,15 +2039,24 @@ static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg, return total; } +#ifdef CONFIG_LOCKDEP +static struct lockdep_map memcg_oom_lock_dep_map = { + .name = "memcg_oom_lock", +}; +#endif + +static DEFINE_SPINLOCK(memcg_oom_lock); + /* * 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) +static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg) { struct mem_cgroup *iter, *failed = NULL; + spin_lock(&memcg_oom_lock); + for_each_mem_cgroup_tree(iter, memcg) { if (iter->oom_lock) { /* @@ -2097,33 +2070,35 @@ static bool mem_cgroup_oom_lock(struct mem_cgroup *memcg) 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; + if (failed) { + /* + * 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; } - iter->oom_lock = false; - } - return false; + } else + mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_); + + spin_unlock(&memcg_oom_lock); + + return !failed; } -/* - * Has to be called with memcg_oom_lock - */ -static int mem_cgroup_oom_unlock(struct mem_cgroup *memcg) +static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg) { struct mem_cgroup *iter; + spin_lock(&memcg_oom_lock); + mutex_release(&memcg_oom_lock_dep_map, 1, _RET_IP_); for_each_mem_cgroup_tree(iter, memcg) iter->oom_lock = false; - return 0; + spin_unlock(&memcg_oom_lock); } static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg) @@ -2147,7 +2122,6 @@ static void mem_cgroup_unmark_under_oom(struct mem_cgroup *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 { @@ -2177,6 +2151,7 @@ static int memcg_oom_wake_function(wait_queue_t *wait, static void memcg_wakeup_oom(struct mem_cgroup *memcg) { + atomic_inc(&memcg->oom_wakeups); /* for filtering, pass "memcg" as argument. */ __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg); } @@ -2187,67 +2162,106 @@ static void memcg_oom_recover(struct mem_cgroup *memcg) memcg_wakeup_oom(memcg); } -/* - * try to call OOM killer. returns false if we should exit memory-reclaim loop. +static void mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order) +{ + if (!current->memcg_oom.may_oom) + return; + /* + * We are in the middle of the charge context here, so we + * don't want to block when potentially sitting on a callstack + * that holds all kinds of filesystem and mm locks. + * + * Also, the caller may handle a failed allocation gracefully + * (like optional page cache readahead) and so an OOM killer + * invocation might not even be necessary. + * + * That's why we don't do anything here except remember the + * OOM context and then deal with it at the end of the page + * fault when the stack is unwound, the locks are released, + * and when we know whether the fault was overall successful. + */ + css_get(&memcg->css); + current->memcg_oom.memcg = memcg; + current->memcg_oom.gfp_mask = mask; + current->memcg_oom.order = order; +} + +/** + * mem_cgroup_oom_synchronize - complete memcg OOM handling + * @handle: actually kill/wait or just clean up the OOM state + * + * This has to be called at the end of a page fault if the memcg OOM + * handler was enabled. + * + * Memcg supports userspace OOM handling where failed allocations must + * sleep on a waitqueue until the userspace task resolves the + * situation. Sleeping directly in the charge context with all kinds + * of locks held is not a good idea, instead we remember an OOM state + * in the task and mem_cgroup_oom_synchronize() has to be called at + * the end of the page fault to complete the OOM handling. + * + * Returns %true if an ongoing memcg OOM situation was detected and + * completed, %false otherwise. */ -static bool mem_cgroup_handle_oom(struct mem_cgroup *memcg, gfp_t mask, - int order) +bool mem_cgroup_oom_synchronize(bool handle) { + struct mem_cgroup *memcg = current->memcg_oom.memcg; struct oom_wait_info owait; - bool locked, need_to_kill; + bool locked; + + /* OOM is global, do not handle */ + if (!memcg) + return false; + + if (!handle) + goto cleanup; owait.memcg = 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; + mem_cgroup_mark_under_oom(memcg); + + locked = mem_cgroup_oom_trylock(memcg); + if (locked) mem_cgroup_oom_notify(memcg); - spin_unlock(&memcg_oom_lock); - if (need_to_kill) { + if (locked && !memcg->oom_kill_disable) { + mem_cgroup_unmark_under_oom(memcg); finish_wait(&memcg_oom_waitq, &owait.wait); - mem_cgroup_out_of_memory(memcg, mask, order); + mem_cgroup_out_of_memory(memcg, current->memcg_oom.gfp_mask, + current->memcg_oom.order); } else { schedule(); + mem_cgroup_unmark_under_oom(memcg); 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); + if (locked) { + mem_cgroup_oom_unlock(memcg); + /* + * There is no guarantee that an OOM-lock contender + * sees the wakeups triggered by the OOM kill + * uncharges. Wake any sleepers explicitely. + */ + memcg_oom_recover(memcg); + } +cleanup: + current->memcg_oom.memcg = NULL; + css_put(&memcg->css); return true; } /* - * Currently used to update mapped file statistics, but the routine can be - * generalized to update other statistics as well. + * Used to update mapped file or writeback or other statistics. * * Notes: Race condition * - * We usually use page_cgroup_lock() for accessing page_cgroup member but + * We usually use lock_page_cgroup() for accessing page_cgroup member but * it tends to be costly. But considering some conditions, we doesn't need * to do so _always_. * @@ -2261,8 +2275,8 @@ static bool mem_cgroup_handle_oom(struct mem_cgroup *memcg, gfp_t mask, * by flags. * * Considering "move", this is an only case we see a race. To make the race - * small, we check mm->moving_account and detect there are possibility of race - * If there is, we take a lock. + * small, we check memcg->moving_account and detect there are possibility + * of race or not. If there is, we take a lock. */ void __mem_cgroup_begin_update_page_stat(struct page *page, @@ -2280,9 +2294,10 @@ again: * If this memory cgroup is not under account moving, we don't * need to take move_lock_mem_cgroup(). Because we already hold * rcu_read_lock(), any calls to move_account will be delayed until - * rcu_read_unlock() if mem_cgroup_stolen() == true. + * rcu_read_unlock(). */ - if (!mem_cgroup_stolen(memcg)) + VM_BUG_ON(!rcu_read_lock_held()); + if (atomic_read(&memcg->moving_account) <= 0) return; move_lock_mem_cgroup(memcg, flags); @@ -2306,7 +2321,7 @@ void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags) } void mem_cgroup_update_page_stat(struct page *page, - enum mem_cgroup_page_stat_item idx, int val) + enum mem_cgroup_stat_index idx, int val) { struct mem_cgroup *memcg; struct page_cgroup *pc = lookup_page_cgroup(page); @@ -2315,18 +2330,11 @@ void mem_cgroup_update_page_stat(struct page *page, if (mem_cgroup_disabled()) return; + VM_BUG_ON(!rcu_read_lock_held()); memcg = pc->mem_cgroup; if (unlikely(!memcg || !PageCgroupUsed(pc))) return; - switch (idx) { - case MEMCG_NR_FILE_MAPPED: - idx = MEM_CGROUP_STAT_FILE_MAPPED; - break; - default: - BUG(); - } - this_cpu_add(memcg->stat->count[idx], val); } @@ -2397,7 +2405,7 @@ static void drain_stock(struct memcg_stock_pcp *stock) */ static void drain_local_stock(struct work_struct *dummy) { - struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock); + struct memcg_stock_pcp *stock = this_cpu_ptr(&memcg_stock); drain_stock(stock); clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); } @@ -2468,7 +2476,7 @@ static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync) flush_work(&stock->work); } out: - put_online_cpus(); + put_online_cpus(); } /* @@ -2521,7 +2529,7 @@ static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu) spin_unlock(&memcg->pcp_counter_lock); } -static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb, +static int memcg_cpu_hotplug_callback(struct notifier_block *nb, unsigned long action, void *hcpu) { @@ -2544,18 +2552,17 @@ static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb, } -/* See __mem_cgroup_try_charge() for details */ +/* 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, unsigned int min_pages, - bool oom_check) + bool invoke_oom) { unsigned long csize = nr_pages * PAGE_SIZE; struct mem_cgroup *mem_over_limit; @@ -2612,171 +2619,117 @@ static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, 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, get_order(csize))) - return CHARGE_OOM_DIE; + if (invoke_oom) + mem_cgroup_oom(mem_over_limit, gfp_mask, get_order(csize)); - return CHARGE_RETRY; + return CHARGE_NOMEM; } -/* - * __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. +/** + * mem_cgroup_try_charge - try charging a memcg + * @memcg: memcg to charge + * @nr_pages: number of pages to charge + * @oom: trigger OOM if reclaim fails * - * Unlike the exported interface, an "oom" parameter is added. if oom==true, - * the oom-killer can be invoked. + * Returns 0 if @memcg was charged successfully, -EINTR if the charge + * was bypassed to root_mem_cgroup, and -ENOMEM if the charge failed. */ -static int __mem_cgroup_try_charge(struct mm_struct *mm, - gfp_t gfp_mask, - unsigned int nr_pages, - struct mem_cgroup **ptr, - bool oom) +static int mem_cgroup_try_charge(struct mem_cgroup *memcg, + gfp_t gfp_mask, + unsigned int nr_pages, + 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; + if (mem_cgroup_is_root(memcg)) + goto done; /* - * 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. + * Unlike in global OOM situations, memcg is not in a physical + * memory shortage. Allow dying and OOM-killed tasks to + * bypass the last charges so that they can exit quickly and + * free their memory. */ - if (unlikely(test_thread_flag(TIF_MEMDIE) - || fatal_signal_pending(current))) + if (unlikely(test_thread_flag(TIF_MEMDIE) || + fatal_signal_pending(current) || + current->flags & PF_EXITING)) 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 root memcg (happens for pagecache usage). - */ - if (!*ptr && !mm) - *ptr = root_mem_cgroup; -again: - if (*ptr) { /* css should be a valid one */ - memcg = *ptr; - if (mem_cgroup_is_root(memcg)) - goto done; - if (consume_stock(memcg, nr_pages)) - goto done; - css_get(&memcg->css); - } else { - struct task_struct *p; + if (unlikely(task_in_memcg_oom(current))) + goto nomem; - 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 (consume_stock(memcg, nr_pages)) { - /* - * 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(); - } + if (gfp_mask & __GFP_NOFAIL) + oom = false; +again: + if (consume_stock(memcg, nr_pages)) + goto done; do { - bool oom_check; + bool invoke_oom = oom && !nr_oom_retries; /* If killed, bypass charge */ - if (fatal_signal_pending(current)) { - css_put(&memcg->css); + if (fatal_signal_pending(current)) 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, nr_pages, - oom_check); + ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, + nr_pages, invoke_oom); 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); + if (!oom || invoke_oom) 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; + if (!(gfp_mask & __GFP_NOFAIL)) + return -ENOMEM; bypass: - *ptr = root_mem_cgroup; return -EINTR; } +/** + * mem_cgroup_try_charge_mm - try charging a mm + * @mm: mm_struct to charge + * @nr_pages: number of pages to charge + * @oom: trigger OOM if reclaim fails + * + * Returns the charged mem_cgroup associated with the given mm_struct or + * NULL the charge failed. + */ +static struct mem_cgroup *mem_cgroup_try_charge_mm(struct mm_struct *mm, + gfp_t gfp_mask, + unsigned int nr_pages, + bool oom) + +{ + struct mem_cgroup *memcg; + int ret; + + memcg = get_mem_cgroup_from_mm(mm); + ret = mem_cgroup_try_charge(memcg, gfp_mask, nr_pages, oom); + css_put(&memcg->css); + if (ret == -EINTR) + memcg = root_mem_cgroup; + else if (ret) + memcg = NULL; + + return memcg; +} + /* * Somemtimes we have to undo a charge we got by try_charge(). * This function is for that and do uncharge, put css's refcnt. @@ -2814,21 +2767,16 @@ static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg, /* * A helper function to get mem_cgroup from ID. must be called under - * rcu_read_lock(). The caller is responsible for calling css_tryget if - * the mem_cgroup is used for charging. (dropping refcnt from swap can be - * called against removed memcg.) + * rcu_read_lock(). The caller is responsible for calling + * css_tryget_online() if the mem_cgroup is used for charging. (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 mem_cgroup_from_css(css); + return mem_cgroup_from_id(id); } struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) @@ -2838,20 +2786,20 @@ struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) unsigned short id; swp_entry_t ent; - VM_BUG_ON(!PageLocked(page)); + VM_BUG_ON_PAGE(!PageLocked(page), page); pc = lookup_page_cgroup(page); lock_page_cgroup(pc); if (PageCgroupUsed(pc)) { memcg = pc->mem_cgroup; - if (memcg && !css_tryget(&memcg->css)) + if (memcg && !css_tryget_online(&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)) + if (memcg && !css_tryget_online(&memcg->css)) memcg = NULL; rcu_read_unlock(); } @@ -2872,7 +2820,7 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, bool anon; lock_page_cgroup(pc); - VM_BUG_ON(PageCgroupUsed(pc)); + VM_BUG_ON_PAGE(PageCgroupUsed(pc), page); /* * we don't need page_cgroup_lock about tail pages, becase they are not * accessed by any other context at this point. @@ -2900,14 +2848,14 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, * 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(); SetPageCgroupUsed(pc); if (lrucare) { if (was_on_lru) { lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup); - VM_BUG_ON(PageLRU(page)); + VM_BUG_ON_PAGE(PageLRU(page), page); SetPageLRU(page); add_page_to_lru_list(page, lruvec, page_lru(page)); } @@ -2933,10 +2881,18 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, static DEFINE_MUTEX(set_limit_mutex); #ifdef CONFIG_MEMCG_KMEM +/* + * The memcg_slab_mutex is held whenever a per memcg kmem cache is created or + * destroyed. It protects memcg_caches arrays and memcg_slab_caches lists. + */ +static DEFINE_MUTEX(memcg_slab_mutex); + +static DEFINE_MUTEX(activate_kmem_mutex); + static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg) { return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) && - (memcg->kmem_account_flags & KMEM_ACCOUNTED_MASK); + memcg_kmem_is_active(memcg); } /* @@ -2949,14 +2905,13 @@ static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p) VM_BUG_ON(p->is_root_cache); cachep = p->root_cache; - return cachep->memcg_params->memcg_caches[memcg_cache_id(p->memcg)]; + return cache_from_memcg_idx(cachep, memcg_cache_id(p->memcg)); } #ifdef CONFIG_SLABINFO -static int mem_cgroup_slabinfo_read(struct cgroup *cont, struct cftype *cft, - struct seq_file *m) +static int mem_cgroup_slabinfo_read(struct seq_file *m, void *v) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); struct memcg_cache_params *params; if (!memcg_can_account_kmem(memcg)) @@ -2964,10 +2919,10 @@ static int mem_cgroup_slabinfo_read(struct cgroup *cont, struct cftype *cft, print_slabinfo_header(m); - mutex_lock(&memcg->slab_caches_mutex); + mutex_lock(&memcg_slab_mutex); list_for_each_entry(params, &memcg->memcg_slab_caches, list) cache_show(memcg_params_to_cache(params), m); - mutex_unlock(&memcg->slab_caches_mutex); + mutex_unlock(&memcg_slab_mutex); return 0; } @@ -2976,27 +2931,17 @@ static int mem_cgroup_slabinfo_read(struct cgroup *cont, struct cftype *cft, static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, u64 size) { struct res_counter *fail_res; - struct mem_cgroup *_memcg; int ret = 0; - bool may_oom; ret = res_counter_charge(&memcg->kmem, size, &fail_res); if (ret) return ret; - /* - * Conditions under which we can wait for the oom_killer. Those are - * the same conditions tested by the core page allocator - */ - may_oom = (gfp & __GFP_FS) && !(gfp & __GFP_NORETRY); - - _memcg = memcg; - ret = __mem_cgroup_try_charge(NULL, gfp, size >> PAGE_SHIFT, - &_memcg, may_oom); - + ret = mem_cgroup_try_charge(memcg, gfp, size >> PAGE_SHIFT, + oom_gfp_allowed(gfp)); if (ret == -EINTR) { /* - * __mem_cgroup_try_charge() chosed to bypass to root due to + * mem_cgroup_try_charge() chosed to bypass to root due to * OOM kill or fatal signal. Since our only options are to * either fail the allocation or charge it to this cgroup, do * it as a temporary condition. But we can't fail. From a @@ -3006,7 +2951,7 @@ static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, u64 size) * * This condition will only trigger if the task entered * memcg_charge_kmem in a sane state, but was OOM-killed during - * __mem_cgroup_try_charge() above. Tasks that were already + * mem_cgroup_try_charge() above. Tasks that were already * dying when the allocation triggers should have been already * directed to the root cgroup in memcontrol.h */ @@ -3031,18 +2976,16 @@ static void memcg_uncharge_kmem(struct mem_cgroup *memcg, u64 size) if (res_counter_uncharge(&memcg->kmem, size)) return; + /* + * Releases a reference taken in kmem_cgroup_css_offline in case + * this last uncharge is racing with the offlining code or it is + * outliving the memcg existence. + * + * The memory barrier imposed by test&clear is paired with the + * explicit one in memcg_kmem_mark_dead(). + */ if (memcg_kmem_test_and_clear_dead(memcg)) - mem_cgroup_put(memcg); -} - -void memcg_cache_list_add(struct mem_cgroup *memcg, struct kmem_cache *cachep) -{ - if (!memcg) - return; - - mutex_lock(&memcg->slab_caches_mutex); - list_add(&cachep->memcg_params->list, &memcg->memcg_slab_caches); - mutex_unlock(&memcg->slab_caches_mutex); + css_put(&memcg->css); } /* @@ -3055,43 +2998,6 @@ int memcg_cache_id(struct mem_cgroup *memcg) return memcg ? memcg->kmemcg_id : -1; } -/* - * This ends up being protected by the set_limit mutex, during normal - * operation, because that is its main call site. - * - * But when we create a new cache, we can call this as well if its parent - * is kmem-limited. That will have to hold set_limit_mutex as well. - */ -int memcg_update_cache_sizes(struct mem_cgroup *memcg) -{ - int num, ret; - - num = ida_simple_get(&kmem_limited_groups, - 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL); - if (num < 0) - return num; - /* - * After this point, kmem_accounted (that we test atomically in - * the beginning of this conditional), is no longer 0. This - * guarantees only one process will set the following boolean - * to true. We don't need test_and_set because we're protected - * by the set_limit_mutex anyway. - */ - memcg_kmem_set_activated(memcg); - - ret = memcg_update_all_caches(num+1); - if (ret) { - ida_simple_remove(&kmem_limited_groups, num); - memcg_kmem_clear_activated(memcg); - return ret; - } - - memcg->kmemcg_id = num; - INIT_LIST_HEAD(&memcg->memcg_slab_caches); - mutex_init(&memcg->slab_caches_mutex); - return 0; -} - static size_t memcg_caches_array_size(int num_groups) { ssize_t size; @@ -3118,28 +3024,25 @@ void memcg_update_array_size(int num) memcg_limited_groups_array_size = memcg_caches_array_size(num); } -static void kmem_cache_destroy_work_func(struct work_struct *w); - int memcg_update_cache_size(struct kmem_cache *s, int num_groups) { struct memcg_cache_params *cur_params = s->memcg_params; - VM_BUG_ON(s->memcg_params && !s->memcg_params->is_root_cache); + VM_BUG_ON(!is_root_cache(s)); if (num_groups > memcg_limited_groups_array_size) { int i; + struct memcg_cache_params *new_params; ssize_t size = memcg_caches_array_size(num_groups); size *= sizeof(void *); - size += sizeof(struct memcg_cache_params); + size += offsetof(struct memcg_cache_params, memcg_caches); - s->memcg_params = kzalloc(size, GFP_KERNEL); - if (!s->memcg_params) { - s->memcg_params = cur_params; + new_params = kzalloc(size, GFP_KERNEL); + if (!new_params) return -ENOMEM; - } - s->memcg_params->is_root_cache = true; + new_params->is_root_cache = true; /* * There is the chance it will be bigger than @@ -3153,7 +3056,7 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups) for (i = 0; i < memcg_limited_groups_array_size; i++) { if (!cur_params->memcg_caches[i]) continue; - s->memcg_params->memcg_caches[i] = + new_params->memcg_caches[i] = cur_params->memcg_caches[i]; } @@ -3166,66 +3069,113 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups) * bigger than the others. And all updates will reset this * anyway. */ - kfree(cur_params); + rcu_assign_pointer(s->memcg_params, new_params); + if (cur_params) + kfree_rcu(cur_params, rcu_head); } return 0; } -int memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s, - struct kmem_cache *root_cache) +int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s, + struct kmem_cache *root_cache) { - size_t size = sizeof(struct memcg_cache_params); + size_t size; if (!memcg_kmem_enabled()) return 0; - if (!memcg) + if (!memcg) { + size = offsetof(struct memcg_cache_params, memcg_caches); size += memcg_limited_groups_array_size * sizeof(void *); + } else + size = sizeof(struct memcg_cache_params); s->memcg_params = kzalloc(size, GFP_KERNEL); if (!s->memcg_params) return -ENOMEM; - INIT_WORK(&s->memcg_params->destroy, - kmem_cache_destroy_work_func); if (memcg) { s->memcg_params->memcg = memcg; s->memcg_params->root_cache = root_cache; + css_get(&memcg->css); } else s->memcg_params->is_root_cache = true; return 0; } -void memcg_release_cache(struct kmem_cache *s) +void memcg_free_cache_params(struct kmem_cache *s) { - struct kmem_cache *root; - struct mem_cgroup *memcg; + if (!s->memcg_params) + return; + if (!s->memcg_params->is_root_cache) + css_put(&s->memcg_params->memcg->css); + kfree(s->memcg_params); +} + +static void memcg_register_cache(struct mem_cgroup *memcg, + struct kmem_cache *root_cache) +{ + static char memcg_name_buf[NAME_MAX + 1]; /* protected by + memcg_slab_mutex */ + struct kmem_cache *cachep; int id; + lockdep_assert_held(&memcg_slab_mutex); + + id = memcg_cache_id(memcg); + /* - * This happens, for instance, when a root cache goes away before we - * add any memcg. + * Since per-memcg caches are created asynchronously on first + * allocation (see memcg_kmem_get_cache()), several threads can try to + * create the same cache, but only one of them may succeed. */ - if (!s->memcg_params) + if (cache_from_memcg_idx(root_cache, id)) return; - if (s->memcg_params->is_root_cache) - goto out; + cgroup_name(memcg->css.cgroup, memcg_name_buf, NAME_MAX + 1); + cachep = memcg_create_kmem_cache(memcg, root_cache, memcg_name_buf); + /* + * If we could not create a memcg cache, do not complain, because + * that's not critical at all as we can always proceed with the root + * cache. + */ + if (!cachep) + return; + + list_add(&cachep->memcg_params->list, &memcg->memcg_slab_caches); + + /* + * Since readers won't lock (see cache_from_memcg_idx()), we need a + * barrier here to ensure nobody will see the kmem_cache partially + * initialized. + */ + smp_wmb(); - memcg = s->memcg_params->memcg; - id = memcg_cache_id(memcg); + BUG_ON(root_cache->memcg_params->memcg_caches[id]); + root_cache->memcg_params->memcg_caches[id] = cachep; +} - root = s->memcg_params->root_cache; - root->memcg_params->memcg_caches[id] = NULL; +static void memcg_unregister_cache(struct kmem_cache *cachep) +{ + struct kmem_cache *root_cache; + struct mem_cgroup *memcg; + int id; - mutex_lock(&memcg->slab_caches_mutex); - list_del(&s->memcg_params->list); - mutex_unlock(&memcg->slab_caches_mutex); + lockdep_assert_held(&memcg_slab_mutex); - mem_cgroup_put(memcg); -out: - kfree(s->memcg_params); + BUG_ON(is_root_cache(cachep)); + + root_cache = cachep->memcg_params->root_cache; + memcg = cachep->memcg_params->memcg; + id = memcg_cache_id(memcg); + + BUG_ON(root_cache->memcg_params->memcg_caches[id] != cachep); + root_cache->memcg_params->memcg_caches[id] = NULL; + + list_del(&cachep->memcg_params->list); + + kmem_cache_destroy(cachep); } /* @@ -3259,241 +3209,74 @@ static inline void memcg_resume_kmem_account(void) current->memcg_kmem_skip_account--; } -static void kmem_cache_destroy_work_func(struct work_struct *w) -{ - struct kmem_cache *cachep; - struct memcg_cache_params *p; - - p = container_of(w, struct memcg_cache_params, destroy); - - cachep = memcg_params_to_cache(p); - - /* - * If we get down to 0 after shrink, we could delete right away. - * However, memcg_release_pages() already puts us back in the workqueue - * in that case. If we proceed deleting, we'll get a dangling - * reference, and removing the object from the workqueue in that case - * is unnecessary complication. We are not a fast path. - * - * Note that this case is fundamentally different from racing with - * shrink_slab(): if memcg_cgroup_destroy_cache() is called in - * kmem_cache_shrink, not only we would be reinserting a dead cache - * into the queue, but doing so from inside the worker racing to - * destroy it. - * - * So if we aren't down to zero, we'll just schedule a worker and try - * again - */ - if (atomic_read(&cachep->memcg_params->nr_pages) != 0) { - kmem_cache_shrink(cachep); - if (atomic_read(&cachep->memcg_params->nr_pages) == 0) - return; - } else - kmem_cache_destroy(cachep); -} - -void mem_cgroup_destroy_cache(struct kmem_cache *cachep) -{ - if (!cachep->memcg_params->dead) - return; - - /* - * There are many ways in which we can get here. - * - * We can get to a memory-pressure situation while the delayed work is - * still pending to run. The vmscan shrinkers can then release all - * cache memory and get us to destruction. If this is the case, we'll - * be executed twice, which is a bug (the second time will execute over - * bogus data). In this case, cancelling the work should be fine. - * - * But we can also get here from the worker itself, if - * kmem_cache_shrink is enough to shake all the remaining objects and - * get the page count to 0. In this case, we'll deadlock if we try to - * cancel the work (the worker runs with an internal lock held, which - * is the same lock we would hold for cancel_work_sync().) - * - * Since we can't possibly know who got us here, just refrain from - * running if there is already work pending - */ - if (work_pending(&cachep->memcg_params->destroy)) - return; - /* - * We have to defer the actual destroying to a workqueue, because - * we might currently be in a context that cannot sleep. - */ - schedule_work(&cachep->memcg_params->destroy); -} - -/* - * This lock protects updaters, not readers. We want readers to be as fast as - * they can, and they will either see NULL or a valid cache value. Our model - * allow them to see NULL, in which case the root memcg will be selected. - * - * We need this lock because multiple allocations to the same cache from a non - * will span more than one worker. Only one of them can create the cache. - */ -static DEFINE_MUTEX(memcg_cache_mutex); - -/* - * Called with memcg_cache_mutex held - */ -static struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg, - struct kmem_cache *s) +int __memcg_cleanup_cache_params(struct kmem_cache *s) { - struct kmem_cache *new; - static char *tmp_name = NULL; - - lockdep_assert_held(&memcg_cache_mutex); - - /* - * kmem_cache_create_memcg duplicates the given name and - * cgroup_name for this name requires RCU context. - * This static temporary buffer is used to prevent from - * pointless shortliving allocation. - */ - if (!tmp_name) { - tmp_name = kmalloc(PATH_MAX, GFP_KERNEL); - if (!tmp_name) - return NULL; - } - - rcu_read_lock(); - snprintf(tmp_name, PATH_MAX, "%s(%d:%s)", s->name, - memcg_cache_id(memcg), cgroup_name(memcg->css.cgroup)); - rcu_read_unlock(); - - new = kmem_cache_create_memcg(memcg, tmp_name, s->object_size, s->align, - (s->flags & ~SLAB_PANIC), s->ctor, s); - - if (new) - new->allocflags |= __GFP_KMEMCG; - - return new; -} - -static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg, - struct kmem_cache *cachep) -{ - struct kmem_cache *new_cachep; - int idx; - - BUG_ON(!memcg_can_account_kmem(memcg)); + struct kmem_cache *c; + int i, failed = 0; - idx = memcg_cache_id(memcg); + mutex_lock(&memcg_slab_mutex); + for_each_memcg_cache_index(i) { + c = cache_from_memcg_idx(s, i); + if (!c) + continue; - mutex_lock(&memcg_cache_mutex); - new_cachep = cachep->memcg_params->memcg_caches[idx]; - if (new_cachep) - goto out; + memcg_unregister_cache(c); - new_cachep = kmem_cache_dup(memcg, cachep); - if (new_cachep == NULL) { - new_cachep = cachep; - goto out; + if (cache_from_memcg_idx(s, i)) + failed++; } - - mem_cgroup_get(memcg); - atomic_set(&new_cachep->memcg_params->nr_pages , 0); - - cachep->memcg_params->memcg_caches[idx] = new_cachep; - /* - * the readers won't lock, make sure everybody sees the updated value, - * so they won't put stuff in the queue again for no reason - */ - wmb(); -out: - mutex_unlock(&memcg_cache_mutex); - return new_cachep; + mutex_unlock(&memcg_slab_mutex); + return failed; } -void kmem_cache_destroy_memcg_children(struct kmem_cache *s) +static void memcg_unregister_all_caches(struct mem_cgroup *memcg) { - struct kmem_cache *c; - int i; + struct kmem_cache *cachep; + struct memcg_cache_params *params, *tmp; - if (!s->memcg_params) - return; - if (!s->memcg_params->is_root_cache) + if (!memcg_kmem_is_active(memcg)) return; - /* - * If the cache is being destroyed, we trust that there is no one else - * requesting objects from it. Even if there are, the sanity checks in - * kmem_cache_destroy should caught this ill-case. - * - * Still, we don't want anyone else freeing memcg_caches under our - * noses, which can happen if a new memcg comes to life. As usual, - * we'll take the set_limit_mutex to protect ourselves against this. - */ - mutex_lock(&set_limit_mutex); - for (i = 0; i < memcg_limited_groups_array_size; i++) { - c = s->memcg_params->memcg_caches[i]; - if (!c) - continue; - - /* - * We will now manually delete the caches, so to avoid races - * we need to cancel all pending destruction workers and - * proceed with destruction ourselves. - * - * kmem_cache_destroy() will call kmem_cache_shrink internally, - * and that could spawn the workers again: it is likely that - * the cache still have active pages until this very moment. - * This would lead us back to mem_cgroup_destroy_cache. - * - * But that will not execute at all if the "dead" flag is not - * set, so flip it down to guarantee we are in control. - */ - c->memcg_params->dead = false; - cancel_work_sync(&c->memcg_params->destroy); - kmem_cache_destroy(c); + mutex_lock(&memcg_slab_mutex); + list_for_each_entry_safe(params, tmp, &memcg->memcg_slab_caches, list) { + cachep = memcg_params_to_cache(params); + kmem_cache_shrink(cachep); + if (atomic_read(&cachep->memcg_params->nr_pages) == 0) + memcg_unregister_cache(cachep); } - mutex_unlock(&set_limit_mutex); + mutex_unlock(&memcg_slab_mutex); } -struct create_work { +struct memcg_register_cache_work { struct mem_cgroup *memcg; struct kmem_cache *cachep; struct work_struct work; }; -static void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg) +static void memcg_register_cache_func(struct work_struct *w) { - struct kmem_cache *cachep; - struct memcg_cache_params *params; - - if (!memcg_kmem_is_active(memcg)) - return; - - mutex_lock(&memcg->slab_caches_mutex); - list_for_each_entry(params, &memcg->memcg_slab_caches, list) { - cachep = memcg_params_to_cache(params); - cachep->memcg_params->dead = true; - schedule_work(&cachep->memcg_params->destroy); - } - mutex_unlock(&memcg->slab_caches_mutex); -} + struct memcg_register_cache_work *cw = + container_of(w, struct memcg_register_cache_work, work); + struct mem_cgroup *memcg = cw->memcg; + struct kmem_cache *cachep = cw->cachep; -static void memcg_create_cache_work_func(struct work_struct *w) -{ - struct create_work *cw; + mutex_lock(&memcg_slab_mutex); + memcg_register_cache(memcg, cachep); + mutex_unlock(&memcg_slab_mutex); - cw = container_of(w, struct create_work, work); - memcg_create_kmem_cache(cw->memcg, cw->cachep); - /* Drop the reference gotten when we enqueued. */ - css_put(&cw->memcg->css); + css_put(&memcg->css); kfree(cw); } /* * Enqueue the creation of a per-memcg kmem_cache. */ -static void __memcg_create_cache_enqueue(struct mem_cgroup *memcg, - struct kmem_cache *cachep) +static void __memcg_schedule_register_cache(struct mem_cgroup *memcg, + struct kmem_cache *cachep) { - struct create_work *cw; + struct memcg_register_cache_work *cw; - cw = kmalloc(sizeof(struct create_work), GFP_NOWAIT); + cw = kmalloc(sizeof(*cw), GFP_NOWAIT); if (cw == NULL) { css_put(&memcg->css); return; @@ -3502,17 +3285,17 @@ static void __memcg_create_cache_enqueue(struct mem_cgroup *memcg, cw->memcg = memcg; cw->cachep = cachep; - INIT_WORK(&cw->work, memcg_create_cache_work_func); + INIT_WORK(&cw->work, memcg_register_cache_func); schedule_work(&cw->work); } -static void memcg_create_cache_enqueue(struct mem_cgroup *memcg, - struct kmem_cache *cachep) +static void memcg_schedule_register_cache(struct mem_cgroup *memcg, + struct kmem_cache *cachep) { /* * We need to stop accounting when we kmalloc, because if the * corresponding kmalloc cache is not yet created, the first allocation - * in __memcg_create_cache_enqueue will recurse. + * in __memcg_schedule_register_cache will recurse. * * However, it is better to enclose the whole function. Depending on * the debugging options enabled, INIT_WORK(), for instance, can @@ -3521,9 +3304,27 @@ static void memcg_create_cache_enqueue(struct mem_cgroup *memcg, * the safest choice is to do it like this, wrapping the whole function. */ memcg_stop_kmem_account(); - __memcg_create_cache_enqueue(memcg, cachep); + __memcg_schedule_register_cache(memcg, cachep); memcg_resume_kmem_account(); } + +int __memcg_charge_slab(struct kmem_cache *cachep, gfp_t gfp, int order) +{ + int res; + + res = memcg_charge_kmem(cachep->memcg_params->memcg, gfp, + PAGE_SIZE << order); + if (!res) + atomic_add(1 << order, &cachep->memcg_params->nr_pages); + return res; +} + +void __memcg_uncharge_slab(struct kmem_cache *cachep, int order) +{ + memcg_uncharge_kmem(cachep->memcg_params->memcg, PAGE_SIZE << order); + atomic_sub(1 << order, &cachep->memcg_params->nr_pages); +} + /* * Return the kmem_cache we're supposed to use for a slab allocation. * We try to use the current memcg's version of the cache. @@ -3541,7 +3342,7 @@ struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp) { struct mem_cgroup *memcg; - int idx; + struct kmem_cache *memcg_cachep; VM_BUG_ON(!cachep->memcg_params); VM_BUG_ON(!cachep->memcg_params->is_root_cache); @@ -3555,20 +3356,14 @@ struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep, if (!memcg_can_account_kmem(memcg)) goto out; - idx = memcg_cache_id(memcg); - - /* - * barrier to mare sure we're always seeing the up to date value. The - * code updating memcg_caches will issue a write barrier to match this. - */ - read_barrier_depends(); - if (likely(cachep->memcg_params->memcg_caches[idx])) { - cachep = cachep->memcg_params->memcg_caches[idx]; + memcg_cachep = cache_from_memcg_idx(cachep, memcg_cache_id(memcg)); + if (likely(memcg_cachep)) { + cachep = memcg_cachep; goto out; } /* The corresponding put will be done in the workqueue. */ - if (!css_tryget(&memcg->css)) + if (!css_tryget_online(&memcg->css)) goto out; rcu_read_unlock(); @@ -3580,22 +3375,16 @@ struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep, * * However, there are some clashes that can arrive from locking. * For instance, because we acquire the slab_mutex while doing - * kmem_cache_dup, this means no further allocation could happen - * with the slab_mutex held. - * - * Also, because cache creation issue get_online_cpus(), this - * creates a lock chain: memcg_slab_mutex -> cpu_hotplug_mutex, - * that ends up reversed during cpu hotplug. (cpuset allocates - * a bunch of GFP_KERNEL memory during cpuup). Due to all that, - * better to defer everything. + * memcg_create_kmem_cache, this means no further allocation + * could happen with the slab_mutex held. So it's better to + * defer everything. */ - memcg_create_cache_enqueue(memcg, cachep); + memcg_schedule_register_cache(memcg, cachep); return cachep; out: rcu_read_unlock(); return cachep; } -EXPORT_SYMBOL(__memcg_kmem_get_cache); /* * We need to verify if the allocation against current->mm->owner's memcg is @@ -3618,16 +3407,37 @@ __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order) int ret; *_memcg = NULL; - memcg = try_get_mem_cgroup_from_mm(current->mm); /* - * very rare case described in mem_cgroup_from_task. Unfortunately there - * isn't much we can do without complicating this too much, and it would - * be gfp-dependent anyway. Just let it go + * Disabling accounting is only relevant for some specific memcg + * internal allocations. Therefore we would initially not have such + * check here, since direct calls to the page allocator that are + * accounted to kmemcg (alloc_kmem_pages and friends) only happen + * outside memcg core. We are mostly concerned with cache allocations, + * and by having this test at memcg_kmem_get_cache, we are already able + * to relay the allocation to the root cache and bypass the memcg cache + * altogether. + * + * There is one exception, though: the SLUB allocator does not create + * large order caches, but rather service large kmallocs directly from + * the page allocator. Therefore, the following sequence when backed by + * the SLUB allocator: + * + * memcg_stop_kmem_account(); + * kmalloc(<large_number>) + * memcg_resume_kmem_account(); + * + * would effectively ignore the fact that we should skip accounting, + * since it will drive us directly to this function without passing + * through the cache selector memcg_kmem_get_cache. Such large + * allocations are extremely rare but can happen, for instance, for the + * cache arrays. We bring this test here. */ - if (unlikely(!memcg)) + if (!current->mm || current->memcg_kmem_skip_account) return true; + memcg = get_mem_cgroup_from_mm(current->mm); + if (!memcg_can_account_kmem(memcg)) { css_put(&memcg->css); return true; @@ -3689,11 +3499,11 @@ void __memcg_kmem_uncharge_pages(struct page *page, int order) if (!memcg) return; - VM_BUG_ON(mem_cgroup_is_root(memcg)); + VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page); memcg_uncharge_kmem(memcg, PAGE_SIZE << order); } #else -static inline void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg) +static inline void memcg_unregister_all_caches(struct mem_cgroup *memcg) { } #endif /* CONFIG_MEMCG_KMEM */ @@ -3755,7 +3565,7 @@ static int mem_cgroup_move_account(struct page *page, bool anon = PageAnon(page); VM_BUG_ON(from == to); - VM_BUG_ON(PageLRU(page)); + VM_BUG_ON_PAGE(PageLRU(page), page); /* * The page is isolated from LRU. So, collapse function * will not handle this page. But page splitting can happen. @@ -3775,12 +3585,19 @@ static int mem_cgroup_move_account(struct page *page, move_lock_mem_cgroup(from, &flags); if (!anon && page_mapped(page)) { - /* 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(); + __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], + nr_pages); + __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], + nr_pages); } + + if (PageWriteback(page)) { + __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK], + nr_pages); + __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_WRITEBACK], + nr_pages); + } + mem_cgroup_charge_statistics(from, page, anon, -nr_pages); /* caller should have done css_get */ @@ -3847,7 +3664,7 @@ static int mem_cgroup_move_parent(struct page *page, parent = root_mem_cgroup; if (nr_pages > 1) { - VM_BUG_ON(!PageTransHuge(page)); + VM_BUG_ON_PAGE(!PageTransHuge(page), page); flags = compound_lock_irqsave(page); } @@ -3865,23 +3682,23 @@ 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) +int mem_cgroup_charge_anon(struct page *page, + struct mm_struct *mm, gfp_t gfp_mask) { - struct mem_cgroup *memcg = NULL; unsigned int nr_pages = 1; + struct mem_cgroup *memcg; bool oom = true; - int ret; + + if (mem_cgroup_disabled()) + return 0; + + VM_BUG_ON_PAGE(page_mapped(page), page); + VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page); + VM_BUG_ON(!mm); if (PageTransHuge(page)) { nr_pages <<= compound_order(page); - VM_BUG_ON(!PageTransHuge(page)); + VM_BUG_ON_PAGE(!PageTransHuge(page), page); /* * Never OOM-kill a process for a huge page. The * fault handler will fall back to regular pages. @@ -3889,25 +3706,14 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, oom = false; } - 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, ctype, false); + memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, nr_pages, oom); + if (!memcg) + return -ENOMEM; + __mem_cgroup_commit_charge(memcg, page, nr_pages, + MEM_CGROUP_CHARGE_TYPE_ANON, 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_ANON); -} - /* * While swap-in, try_charge -> commit or cancel, the page is locked. * And when try_charge() successfully returns, one refcnt to memcg without @@ -3919,7 +3725,7 @@ static int __mem_cgroup_try_charge_swapin(struct mm_struct *mm, gfp_t mask, struct mem_cgroup **memcgp) { - struct mem_cgroup *memcg; + struct mem_cgroup *memcg = NULL; struct page_cgroup *pc; int ret; @@ -3932,31 +3738,29 @@ static int __mem_cgroup_try_charge_swapin(struct mm_struct *mm, * in turn serializes uncharging. */ if (PageCgroupUsed(pc)) - return 0; - if (!do_swap_account) - goto charge_cur_mm; - memcg = try_get_mem_cgroup_from_page(page); + goto out; + if (do_swap_account) + 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); + memcg = get_mem_cgroup_from_mm(mm); + ret = mem_cgroup_try_charge(memcg, mask, 1, true); css_put(&memcg->css); if (ret == -EINTR) - ret = 0; - return ret; -charge_cur_mm: - ret = __mem_cgroup_try_charge(mm, mask, 1, memcgp, true); - if (ret == -EINTR) - ret = 0; - return ret; + memcg = root_mem_cgroup; + else if (ret) + return ret; +out: + *memcgp = memcg; + return 0; } int mem_cgroup_try_charge_swapin(struct mm_struct *mm, struct page *page, gfp_t gfp_mask, struct mem_cgroup **memcgp) { - *memcgp = NULL; - if (mem_cgroup_disabled()) + if (mem_cgroup_disabled()) { + *memcgp = NULL; return 0; + } /* * A racing thread's fault, or swapoff, may have already * updated the pte, and even removed page from swap cache: in @@ -3964,12 +3768,13 @@ int mem_cgroup_try_charge_swapin(struct mm_struct *mm, struct page *page, * there's also a KSM case which does need to charge the page. */ if (!PageSwapCache(page)) { - int ret; + struct mem_cgroup *memcg; - ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, memcgp, true); - if (ret == -EINTR) - ret = 0; - return ret; + memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, 1, true); + if (!memcg) + return -ENOMEM; + *memcgp = memcg; + return 0; } return __mem_cgroup_try_charge_swapin(mm, page, gfp_mask, memcgp); } @@ -4013,11 +3818,11 @@ void mem_cgroup_commit_charge_swapin(struct page *page, MEM_CGROUP_CHARGE_TYPE_ANON); } -int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, +int mem_cgroup_charge_file(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; + struct mem_cgroup *memcg; int ret; if (mem_cgroup_disabled()) @@ -4025,15 +3830,20 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, if (PageCompound(page)) return 0; - if (!PageSwapCache(page)) - ret = mem_cgroup_charge_common(page, mm, gfp_mask, type); - else { /* page is swapcache/shmem */ + if (PageSwapCache(page)) { /* shmem */ ret = __mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &memcg); - if (!ret) - __mem_cgroup_commit_charge_swapin(page, memcg, type); + if (ret) + return ret; + __mem_cgroup_commit_charge_swapin(page, memcg, type); + return 0; } - return ret; + + memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, 1, true); + if (!memcg) + return -ENOMEM; + __mem_cgroup_commit_charge(memcg, page, 1, type, false); + return 0; } static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg, @@ -4106,7 +3916,7 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype, if (PageTransHuge(page)) { nr_pages <<= compound_order(page); - VM_BUG_ON(!PageTransHuge(page)); + VM_BUG_ON_PAGE(!PageTransHuge(page), page); } /* * Check if our page_cgroup is valid @@ -4171,12 +3981,12 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype, unlock_page_cgroup(pc); /* * even after unlock, we have memcg->res.usage here and this memcg - * will never be freed. + * will never be freed, so it's safe to call css_get(). */ 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); + css_get(&memcg->css); } /* * Migration does not charge the res_counter for the @@ -4198,7 +4008,7 @@ void mem_cgroup_uncharge_page(struct page *page) /* early check. */ if (page_mapped(page)) return; - VM_BUG_ON(page->mapping && !PageAnon(page)); + VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page); /* * If the page is in swap cache, uncharge should be deferred * to the swap path, which also properly accounts swap usage @@ -4218,8 +4028,8 @@ void mem_cgroup_uncharge_page(struct page *page) void mem_cgroup_uncharge_cache_page(struct page *page) { - VM_BUG_ON(page_mapped(page)); - VM_BUG_ON(page->mapping); + VM_BUG_ON_PAGE(page_mapped(page), page); + VM_BUG_ON_PAGE(page->mapping, page); __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false); } @@ -4288,10 +4098,10 @@ mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) /* * record memcg information, if swapout && memcg != NULL, - * mem_cgroup_get() was called in uncharge(). + * css_get() was called in uncharge(). */ if (do_swap_account && swapout && memcg) - swap_cgroup_record(ent, css_id(&memcg->css)); + swap_cgroup_record(ent, mem_cgroup_id(memcg)); } #endif @@ -4313,13 +4123,13 @@ void mem_cgroup_uncharge_swap(swp_entry_t ent) 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 + * We uncharge this because swap is freed. This memcg can + * be obsolete one. We avoid calling css_tryget_online(). */ if (!mem_cgroup_is_root(memcg)) res_counter_uncharge(&memcg->memsw, PAGE_SIZE); mem_cgroup_swap_statistics(memcg, false); - mem_cgroup_put(memcg); + css_put(&memcg->css); } rcu_read_unlock(); } @@ -4343,8 +4153,8 @@ static int mem_cgroup_move_swap_account(swp_entry_t entry, { unsigned short old_id, new_id; - old_id = css_id(&from->css); - new_id = css_id(&to->css); + old_id = mem_cgroup_id(from); + new_id = mem_cgroup_id(to); if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { mem_cgroup_swap_statistics(from, false); @@ -4353,11 +4163,14 @@ static int mem_cgroup_move_swap_account(swp_entry_t entry, * 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. + * improvement. But we cannot postpone css_get(to) because if + * the process that has been moved to @to does swap-in, the + * refcount of @to might be decreased to 0. + * + * We are in attach() phase, so the cgroup is guaranteed to be + * alive, so we can just call css_get(). */ - mem_cgroup_get(to); + css_get(&to->css); return 0; } return -EINVAL; @@ -4633,7 +4446,7 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, MEM_CGROUP_RECLAIM_SHRINK); curusage = res_counter_read_u64(&memcg->res, RES_USAGE); /* Usage is reduced ? */ - if (curusage >= oldusage) + if (curusage >= oldusage) retry_count--; else oldusage = curusage; @@ -4654,7 +4467,7 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, int enlarge = 0; /* see mem_cgroup_resize_res_limit */ - retry_count = children * MEM_CGROUP_RECLAIM_RETRIES; + retry_count = children * MEM_CGROUP_RECLAIM_RETRIES; oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); while (retry_count) { if (signal_pending(current)) { @@ -4765,7 +4578,7 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, break; } while (1); } - __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz); + __mem_cgroup_remove_exceeded(mz, mctz); excess = res_counter_soft_limit_excess(&mz->memcg->res); /* * One school of thought says that we should not add @@ -4776,7 +4589,7 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, * term TODO. */ /* If excess == 0, no tree ops */ - __mem_cgroup_insert_exceeded(mz->memcg, mz, mctz, excess); + __mem_cgroup_insert_exceeded(mz, mctz, excess); spin_unlock(&mctz->lock); css_put(&mz->memcg->css); loop++; @@ -4843,9 +4656,9 @@ static void mem_cgroup_force_empty_list(struct mem_cgroup *memcg, if (mem_cgroup_move_parent(page, pc, memcg)) { /* found lock contention or "pc" is obsolete. */ busy = page; - cond_resched(); } else busy = NULL; + cond_resched(); } while (!list_empty(list)); } @@ -4897,30 +4710,27 @@ static void mem_cgroup_reparent_charges(struct mem_cgroup *memcg) } /* - * This mainly exists for tests during the setting of set of use_hierarchy. - * Since this is the very setting we are changing, the current hierarchy value - * is meaningless + * Test whether @memcg has children, dead or alive. Note that this + * function doesn't care whether @memcg has use_hierarchy enabled and + * returns %true if there are child csses according to the cgroup + * hierarchy. Testing use_hierarchy is the caller's responsiblity. */ -static inline bool __memcg_has_children(struct mem_cgroup *memcg) +static inline bool memcg_has_children(struct mem_cgroup *memcg) { - struct cgroup *pos; + bool ret; - /* bounce at first found */ - cgroup_for_each_child(pos, memcg->css.cgroup) - return true; - return false; -} + /* + * The lock does not prevent addition or deletion of children, but + * it prevents a new child from being initialized based on this + * parent in css_online(), so it's enough to decide whether + * hierarchically inherited attributes can still be changed or not. + */ + lockdep_assert_held(&memcg_create_mutex); -/* - * Must be called with memcg_create_mutex held, unless the cgroup is guaranteed - * to be already dead (as in mem_cgroup_force_empty, for instance). This is - * from mem_cgroup_count_children(), in the sense that we don't really care how - * many children we have; we only need to know if we have any. It also counts - * any memcg without hierarchy as infertile. - */ -static inline bool memcg_has_children(struct mem_cgroup *memcg) -{ - return memcg->use_hierarchy && __memcg_has_children(memcg); + rcu_read_lock(); + ret = css_next_child(NULL, &memcg->css); + rcu_read_unlock(); + return ret; } /* @@ -4932,11 +4742,6 @@ static inline bool memcg_has_children(struct mem_cgroup *memcg) static int mem_cgroup_force_empty(struct mem_cgroup *memcg) { int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; - struct cgroup *cgrp = memcg->css.cgroup; - - /* returns EBUSY if there is a task or if we come here twice. */ - if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children)) - return -EBUSY; /* we call try-to-free pages for make this cgroup empty */ lru_add_drain_all(); @@ -4956,42 +4761,33 @@ static int mem_cgroup_force_empty(struct mem_cgroup *memcg) } } - lru_add_drain(); - mem_cgroup_reparent_charges(memcg); return 0; } -static int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event) +static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, + loff_t off) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); - int ret; + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); if (mem_cgroup_is_root(memcg)) return -EINVAL; - css_get(&memcg->css); - ret = mem_cgroup_force_empty(memcg); - css_put(&memcg->css); - - return ret; + return mem_cgroup_force_empty(memcg) ?: nbytes; } - -static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft) +static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css, + struct cftype *cft) { - return mem_cgroup_from_cont(cont)->use_hierarchy; + return mem_cgroup_from_css(css)->use_hierarchy; } -static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft, - u64 val) +static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css, + struct cftype *cft, u64 val) { int retval = 0; - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); - struct cgroup *parent = cont->parent; - struct mem_cgroup *parent_memcg = NULL; - - if (parent) - parent_memcg = mem_cgroup_from_cont(parent); + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + struct mem_cgroup *parent_memcg = mem_cgroup_from_css(memcg->css.parent); mutex_lock(&memcg_create_mutex); @@ -5008,7 +4804,7 @@ static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft, */ if ((!parent_memcg || !parent_memcg->use_hierarchy) && (val == 1 || val == 0)) { - if (!__memcg_has_children(memcg)) + if (!memcg_has_children(memcg)) memcg->use_hierarchy = val; else retval = -EBUSY; @@ -5061,14 +4857,12 @@ static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) return val << PAGE_SHIFT; } -static ssize_t mem_cgroup_read(struct cgroup *cont, struct cftype *cft, - struct file *file, char __user *buf, - size_t nbytes, loff_t *ppos) +static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css, + struct cftype *cft) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); - char str[64]; + struct mem_cgroup *memcg = mem_cgroup_from_css(css); u64 val; - int name, len; + int name; enum res_type type; type = MEMFILE_TYPE(cft->private); @@ -5094,15 +4888,26 @@ static ssize_t mem_cgroup_read(struct cgroup *cont, struct cftype *cft, BUG(); } - len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val); - return simple_read_from_buffer(buf, nbytes, ppos, str, len); + return val; } -static int memcg_update_kmem_limit(struct cgroup *cont, u64 val) -{ - int ret = -EINVAL; #ifdef CONFIG_MEMCG_KMEM - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); +/* should be called with activate_kmem_mutex held */ +static int __memcg_activate_kmem(struct mem_cgroup *memcg, + unsigned long long limit) +{ + int err = 0; + int memcg_id; + + if (memcg_kmem_is_active(memcg)) + return 0; + + /* + * We are going to allocate memory for data shared by all memory + * cgroups so let's stop accounting here. + */ + memcg_stop_kmem_account(); + /* * For simplicity, we won't allow this to be disabled. It also can't * be changed if the cgroup has children already, or if tasks had @@ -5116,97 +4921,121 @@ static int memcg_update_kmem_limit(struct cgroup *cont, u64 val) * of course permitted. */ mutex_lock(&memcg_create_mutex); - mutex_lock(&set_limit_mutex); - if (!memcg->kmem_account_flags && val != RESOURCE_MAX) { - if (cgroup_task_count(cont) || memcg_has_children(memcg)) { - ret = -EBUSY; - goto out; - } - ret = res_counter_set_limit(&memcg->kmem, val); - VM_BUG_ON(ret); + if (cgroup_has_tasks(memcg->css.cgroup) || + (memcg->use_hierarchy && memcg_has_children(memcg))) + err = -EBUSY; + mutex_unlock(&memcg_create_mutex); + if (err) + goto out; - ret = memcg_update_cache_sizes(memcg); - if (ret) { - res_counter_set_limit(&memcg->kmem, RESOURCE_MAX); - goto out; - } - static_key_slow_inc(&memcg_kmem_enabled_key); - /* - * setting the active bit after the inc will guarantee no one - * starts accounting before all call sites are patched - */ - memcg_kmem_set_active(memcg); + memcg_id = ida_simple_get(&kmem_limited_groups, + 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL); + if (memcg_id < 0) { + err = memcg_id; + goto out; + } - /* - * kmem charges can outlive the cgroup. In the case of slab - * pages, for instance, a page contain objects from various - * processes, so it is unfeasible to migrate them away. We - * need to reference count the memcg because of that. - */ - mem_cgroup_get(memcg); - } else - ret = res_counter_set_limit(&memcg->kmem, val); + /* + * Make sure we have enough space for this cgroup in each root cache's + * memcg_params. + */ + mutex_lock(&memcg_slab_mutex); + err = memcg_update_all_caches(memcg_id + 1); + mutex_unlock(&memcg_slab_mutex); + if (err) + goto out_rmid; + + memcg->kmemcg_id = memcg_id; + INIT_LIST_HEAD(&memcg->memcg_slab_caches); + + /* + * We couldn't have accounted to this cgroup, because it hasn't got the + * active bit set yet, so this should succeed. + */ + err = res_counter_set_limit(&memcg->kmem, limit); + VM_BUG_ON(err); + + static_key_slow_inc(&memcg_kmem_enabled_key); + /* + * Setting the active bit after enabling static branching will + * guarantee no one starts accounting before all call sites are + * patched. + */ + memcg_kmem_set_active(memcg); out: - mutex_unlock(&set_limit_mutex); - mutex_unlock(&memcg_create_mutex); -#endif + memcg_resume_kmem_account(); + return err; + +out_rmid: + ida_simple_remove(&kmem_limited_groups, memcg_id); + goto out; +} + +static int memcg_activate_kmem(struct mem_cgroup *memcg, + unsigned long long limit) +{ + int ret; + + mutex_lock(&activate_kmem_mutex); + ret = __memcg_activate_kmem(memcg, limit); + mutex_unlock(&activate_kmem_mutex); + return ret; +} + +static int memcg_update_kmem_limit(struct mem_cgroup *memcg, + unsigned long long val) +{ + int ret; + + if (!memcg_kmem_is_active(memcg)) + ret = memcg_activate_kmem(memcg, val); + else + ret = res_counter_set_limit(&memcg->kmem, val); return ret; } -#ifdef CONFIG_MEMCG_KMEM static int memcg_propagate_kmem(struct mem_cgroup *memcg) { int ret = 0; struct mem_cgroup *parent = parent_mem_cgroup(memcg); - if (!parent) - goto out; - memcg->kmem_account_flags = parent->kmem_account_flags; - /* - * When that happen, we need to disable the static branch only on those - * memcgs that enabled it. To achieve this, we would be forced to - * complicate the code by keeping track of which memcgs were the ones - * that actually enabled limits, and which ones got it from its - * parents. - * - * It is a lot simpler just to do static_key_slow_inc() on every child - * that is accounted. - */ - if (!memcg_kmem_is_active(memcg)) - goto out; + if (!parent) + return 0; + mutex_lock(&activate_kmem_mutex); /* - * destroy(), called if we fail, will issue static_key_slow_inc() and - * mem_cgroup_put() if kmem is enabled. We have to either call them - * unconditionally, or clear the KMEM_ACTIVE flag. I personally find - * this more consistent, since it always leads to the same destroy path + * If the parent cgroup is not kmem-active now, it cannot be activated + * after this point, because it has at least one child already. */ - mem_cgroup_get(memcg); - static_key_slow_inc(&memcg_kmem_enabled_key); - - mutex_lock(&set_limit_mutex); - ret = memcg_update_cache_sizes(memcg); - mutex_unlock(&set_limit_mutex); -out: + if (memcg_kmem_is_active(parent)) + ret = __memcg_activate_kmem(memcg, RES_COUNTER_MAX); + mutex_unlock(&activate_kmem_mutex); return ret; } +#else +static int memcg_update_kmem_limit(struct mem_cgroup *memcg, + unsigned long long val) +{ + return -EINVAL; +} #endif /* CONFIG_MEMCG_KMEM */ /* * The user of this function is... * RES_LIMIT. */ -static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft, - const char *buffer) +static ssize_t mem_cgroup_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); enum res_type type; int name; unsigned long long val; int ret; - type = MEMFILE_TYPE(cft->private); - name = MEMFILE_ATTR(cft->private); + buf = strstrip(buf); + type = MEMFILE_TYPE(of_cft(of)->private); + name = MEMFILE_ATTR(of_cft(of)->private); switch (name) { case RES_LIMIT: @@ -5215,7 +5044,7 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft, break; } /* This function does all necessary parse...reuse it */ - ret = res_counter_memparse_write_strategy(buffer, &val); + ret = res_counter_memparse_write_strategy(buf, &val); if (ret) break; if (type == _MEM) @@ -5223,12 +5052,12 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft, else if (type == _MEMSWAP) ret = mem_cgroup_resize_memsw_limit(memcg, val); else if (type == _KMEM) - ret = memcg_update_kmem_limit(cont, val); + ret = memcg_update_kmem_limit(memcg, val); else return -EINVAL; break; case RES_SOFT_LIMIT: - ret = res_counter_memparse_write_strategy(buffer, &val); + ret = res_counter_memparse_write_strategy(buf, &val); if (ret) break; /* @@ -5245,24 +5074,21 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft, ret = -EINVAL; /* should be BUG() ? */ break; } - return ret; + return ret ?: nbytes; } static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg, unsigned long long *mem_limit, unsigned long long *memsw_limit) { - struct cgroup *cgroup; unsigned long long min_limit, min_memsw_limit, tmp; min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT); min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); - cgroup = memcg->css.cgroup; if (!memcg->use_hierarchy) goto out; - while (cgroup->parent) { - cgroup = cgroup->parent; - memcg = mem_cgroup_from_cont(cgroup); + while (memcg->css.parent) { + memcg = mem_cgroup_from_css(memcg->css.parent); if (!memcg->use_hierarchy) break; tmp = res_counter_read_u64(&memcg->res, RES_LIMIT); @@ -5275,14 +5101,15 @@ out: *memsw_limit = min_memsw_limit; } -static int mem_cgroup_reset(struct cgroup *cont, unsigned int event) +static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf, + size_t nbytes, loff_t off) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); int name; enum res_type type; - type = MEMFILE_TYPE(event); - name = MEMFILE_ATTR(event); + type = MEMFILE_TYPE(of_cft(of)->private); + name = MEMFILE_ATTR(of_cft(of)->private); switch (name) { case RES_MAX_USAGE: @@ -5307,20 +5134,20 @@ static int mem_cgroup_reset(struct cgroup *cont, unsigned int event) break; } - return 0; + return nbytes; } -static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp, +static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css, struct cftype *cft) { - return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate; + return mem_cgroup_from_css(css)->move_charge_at_immigrate; } #ifdef CONFIG_MMU -static int mem_cgroup_move_charge_write(struct cgroup *cgrp, +static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, struct cftype *cft, u64 val) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + struct mem_cgroup *memcg = mem_cgroup_from_css(css); if (val >= (1 << NR_MOVE_TYPE)) return -EINVAL; @@ -5335,7 +5162,7 @@ static int mem_cgroup_move_charge_write(struct cgroup *cgrp, return 0; } #else -static int mem_cgroup_move_charge_write(struct cgroup *cgrp, +static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, struct cftype *cft, u64 val) { return -ENOSYS; @@ -5343,48 +5170,52 @@ static int mem_cgroup_move_charge_write(struct cgroup *cgrp, #endif #ifdef CONFIG_NUMA -static int memcg_numa_stat_show(struct cgroup *cont, struct cftype *cft, - struct seq_file *m) +static int memcg_numa_stat_show(struct seq_file *m, void *v) { - int nid; - unsigned long total_nr, file_nr, anon_nr, unevictable_nr; - unsigned long node_nr; - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); - - total_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL); - seq_printf(m, "total=%lu", total_nr); - for_each_node_state(nid, N_MEMORY) { - node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL); - seq_printf(m, " N%d=%lu", nid, node_nr); - } - seq_putc(m, '\n'); - - file_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL_FILE); - seq_printf(m, "file=%lu", file_nr); - for_each_node_state(nid, N_MEMORY) { - node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, - LRU_ALL_FILE); - seq_printf(m, " N%d=%lu", nid, node_nr); - } - seq_putc(m, '\n'); + struct numa_stat { + const char *name; + unsigned int lru_mask; + }; - anon_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL_ANON); - seq_printf(m, "anon=%lu", anon_nr); - for_each_node_state(nid, N_MEMORY) { - node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, - LRU_ALL_ANON); - seq_printf(m, " N%d=%lu", nid, node_nr); + static const struct numa_stat stats[] = { + { "total", LRU_ALL }, + { "file", LRU_ALL_FILE }, + { "anon", LRU_ALL_ANON }, + { "unevictable", BIT(LRU_UNEVICTABLE) }, + }; + const struct numa_stat *stat; + int nid; + unsigned long nr; + struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); + + for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { + nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask); + seq_printf(m, "%s=%lu", stat->name, nr); + for_each_node_state(nid, N_MEMORY) { + nr = mem_cgroup_node_nr_lru_pages(memcg, nid, + stat->lru_mask); + seq_printf(m, " N%d=%lu", nid, nr); + } + seq_putc(m, '\n'); + } + + for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { + struct mem_cgroup *iter; + + nr = 0; + for_each_mem_cgroup_tree(iter, memcg) + nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask); + seq_printf(m, "hierarchical_%s=%lu", stat->name, nr); + for_each_node_state(nid, N_MEMORY) { + nr = 0; + for_each_mem_cgroup_tree(iter, memcg) + nr += mem_cgroup_node_nr_lru_pages( + iter, nid, stat->lru_mask); + seq_printf(m, " N%d=%lu", nid, nr); + } + seq_putc(m, '\n'); } - seq_putc(m, '\n'); - unevictable_nr = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_UNEVICTABLE)); - seq_printf(m, "unevictable=%lu", unevictable_nr); - for_each_node_state(nid, N_MEMORY) { - node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, - BIT(LRU_UNEVICTABLE)); - seq_printf(m, " N%d=%lu", nid, node_nr); - } - seq_putc(m, '\n'); return 0; } #endif /* CONFIG_NUMA */ @@ -5394,10 +5225,9 @@ static inline void mem_cgroup_lru_names_not_uptodate(void) BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS); } -static int memcg_stat_show(struct cgroup *cont, struct cftype *cft, - struct seq_file *m) +static int memcg_stat_show(struct seq_file *m, void *v) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); struct mem_cgroup *mi; unsigned int i; @@ -5463,7 +5293,7 @@ static int memcg_stat_show(struct cgroup *cont, struct cftype *cft, for_each_online_node(nid) for (zid = 0; zid < MAX_NR_ZONES; zid++) { - mz = mem_cgroup_zoneinfo(memcg, nid, zid); + mz = &memcg->nodeinfo[nid]->zoneinfo[zid]; rstat = &mz->lruvec.reclaim_stat; recent_rotated[0] += rstat->recent_rotated[0]; @@ -5481,38 +5311,26 @@ static int memcg_stat_show(struct cgroup *cont, struct cftype *cft, return 0; } -static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft) +static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css, + struct cftype *cft) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + struct mem_cgroup *memcg = mem_cgroup_from_css(css); return mem_cgroup_swappiness(memcg); } -static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft, - u64 val) +static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css, + struct cftype *cft, u64 val) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); - struct mem_cgroup *parent; + struct mem_cgroup *memcg = mem_cgroup_from_css(css); if (val > 100) return -EINVAL; - if (cgrp->parent == NULL) - return -EINVAL; - - parent = mem_cgroup_from_cont(cgrp->parent); - - mutex_lock(&memcg_create_mutex); - - /* If under hierarchy, only empty-root can set this value */ - if ((parent->use_hierarchy) || memcg_has_children(memcg)) { - mutex_unlock(&memcg_create_mutex); - return -EINVAL; - } - - memcg->swappiness = val; - - mutex_unlock(&memcg_create_mutex); + if (css->parent) + memcg->swappiness = val; + else + vm_swappiness = val; return 0; } @@ -5584,15 +5402,25 @@ static int compare_thresholds(const void *a, const void *b) const struct mem_cgroup_threshold *_a = a; const struct mem_cgroup_threshold *_b = b; - return _a->threshold - _b->threshold; + if (_a->threshold > _b->threshold) + return 1; + + if (_a->threshold < _b->threshold) + return -1; + + return 0; } static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg) { struct mem_cgroup_eventfd_list *ev; + spin_lock(&memcg_oom_lock); + list_for_each_entry(ev, &memcg->oom_notify, list) eventfd_signal(ev->eventfd, 1); + + spin_unlock(&memcg_oom_lock); return 0; } @@ -5604,13 +5432,11 @@ static void mem_cgroup_oom_notify(struct mem_cgroup *memcg) mem_cgroup_oom_notify_cb(iter); } -static int mem_cgroup_usage_register_event(struct cgroup *cgrp, - struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) +static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd, const char *args, enum res_type type) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); struct mem_cgroup_thresholds *thresholds; struct mem_cgroup_threshold_ary *new; - enum res_type type = MEMFILE_TYPE(cft->private); u64 threshold, usage; int i, size, ret; @@ -5687,13 +5513,23 @@ unlock: return ret; } -static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp, - struct cftype *cft, struct eventfd_ctx *eventfd) +static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd, const char *args) +{ + return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM); +} + +static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd, const char *args) +{ + return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP); +} + +static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd, enum res_type type) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); struct mem_cgroup_thresholds *thresholds; struct mem_cgroup_threshold_ary *new; - enum res_type type = MEMFILE_TYPE(cft->private); u64 usage; int i, j, size; @@ -5766,14 +5602,23 @@ unlock: mutex_unlock(&memcg->thresholds_lock); } -static int mem_cgroup_oom_register_event(struct cgroup *cgrp, - struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) +static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd) +{ + return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM); +} + +static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd) +{ + return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP); +} + +static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd, const char *args) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); struct mem_cgroup_eventfd_list *event; - enum res_type type = MEMFILE_TYPE(cft->private); - BUG_ON(type != _OOM_TYPE); event = kmalloc(sizeof(*event), GFP_KERNEL); if (!event) return -ENOMEM; @@ -5791,14 +5636,10 @@ static int mem_cgroup_oom_register_event(struct cgroup *cgrp, return 0; } -static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp, - struct cftype *cft, struct eventfd_ctx *eventfd) +static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg, + struct eventfd_ctx *eventfd) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); struct mem_cgroup_eventfd_list *ev, *tmp; - enum res_type type = MEMFILE_TYPE(cft->private); - - BUG_ON(type != _OOM_TYPE); spin_lock(&memcg_oom_lock); @@ -5812,42 +5653,28 @@ static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp, spin_unlock(&memcg_oom_lock); } -static int mem_cgroup_oom_control_read(struct cgroup *cgrp, - struct cftype *cft, struct cgroup_map_cb *cb) +static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); - - cb->fill(cb, "oom_kill_disable", memcg->oom_kill_disable); + struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(sf)); - if (atomic_read(&memcg->under_oom)) - cb->fill(cb, "under_oom", 1); - else - cb->fill(cb, "under_oom", 0); + seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable); + seq_printf(sf, "under_oom %d\n", (bool)atomic_read(&memcg->under_oom)); return 0; } -static int mem_cgroup_oom_control_write(struct cgroup *cgrp, +static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css, struct cftype *cft, u64 val) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); - struct mem_cgroup *parent; + struct mem_cgroup *memcg = mem_cgroup_from_css(css); /* cannot set to root cgroup and only 0 and 1 are allowed */ - if (!cgrp->parent || !((val == 0) || (val == 1))) + if (!css->parent || !((val == 0) || (val == 1))) return -EINVAL; - parent = mem_cgroup_from_cont(cgrp->parent); - - mutex_lock(&memcg_create_mutex); - /* oom-kill-disable is a flag for subhierarchy. */ - if ((parent->use_hierarchy) || memcg_has_children(memcg)) { - mutex_unlock(&memcg_create_mutex); - return -EINVAL; - } memcg->oom_kill_disable = val; if (!val) memcg_oom_recover(memcg); - mutex_unlock(&memcg_create_mutex); + return 0; } @@ -5864,23 +5691,43 @@ static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss) return mem_cgroup_sockets_init(memcg, ss); } -static void kmem_cgroup_destroy(struct mem_cgroup *memcg) +static void memcg_destroy_kmem(struct mem_cgroup *memcg) { mem_cgroup_sockets_destroy(memcg); +} + +static void kmem_cgroup_css_offline(struct mem_cgroup *memcg) +{ + if (!memcg_kmem_is_active(memcg)) + return; + + /* + * kmem charges can outlive the cgroup. In the case of slab + * pages, for instance, a page contain objects from various + * processes. As we prevent from taking a reference for every + * such allocation we have to be careful when doing uncharge + * (see memcg_uncharge_kmem) and here during offlining. + * + * The idea is that that only the _last_ uncharge which sees + * the dead memcg will drop the last reference. An additional + * reference is taken here before the group is marked dead + * which is then paired with css_put during uncharge resp. here. + * + * Although this might sound strange as this path is called from + * css_offline() when the referencemight have dropped down to 0 and + * shouldn't be incremented anymore (css_tryget_online() would + * fail) we do not have other options because of the kmem + * allocations lifetime. + */ + css_get(&memcg->css); memcg_kmem_mark_dead(memcg); if (res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0) return; - /* - * Charges already down to 0, undo mem_cgroup_get() done in the charge - * path here, being careful not to race with memcg_uncharge_kmem: it is - * possible that the charges went down to 0 between mark_dead and the - * res_counter read, so in that case, we don't need the put - */ if (memcg_kmem_test_and_clear_dead(memcg)) - mem_cgroup_put(memcg); + css_put(&memcg->css); } #else static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss) @@ -5888,50 +5735,275 @@ static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss) return 0; } -static void kmem_cgroup_destroy(struct mem_cgroup *memcg) +static void memcg_destroy_kmem(struct mem_cgroup *memcg) +{ +} + +static void kmem_cgroup_css_offline(struct mem_cgroup *memcg) { } #endif +/* + * DO NOT USE IN NEW FILES. + * + * "cgroup.event_control" implementation. + * + * This is way over-engineered. It tries to support fully configurable + * events for each user. Such level of flexibility is completely + * unnecessary especially in the light of the planned unified hierarchy. + * + * Please deprecate this and replace with something simpler if at all + * possible. + */ + +/* + * Unregister event and free resources. + * + * Gets called from workqueue. + */ +static void memcg_event_remove(struct work_struct *work) +{ + struct mem_cgroup_event *event = + container_of(work, struct mem_cgroup_event, remove); + struct mem_cgroup *memcg = event->memcg; + + remove_wait_queue(event->wqh, &event->wait); + + event->unregister_event(memcg, event->eventfd); + + /* Notify userspace the event is going away. */ + eventfd_signal(event->eventfd, 1); + + eventfd_ctx_put(event->eventfd); + kfree(event); + css_put(&memcg->css); +} + +/* + * Gets called on POLLHUP on eventfd when user closes it. + * + * Called with wqh->lock held and interrupts disabled. + */ +static int memcg_event_wake(wait_queue_t *wait, unsigned mode, + int sync, void *key) +{ + struct mem_cgroup_event *event = + container_of(wait, struct mem_cgroup_event, wait); + struct mem_cgroup *memcg = event->memcg; + unsigned long flags = (unsigned long)key; + + if (flags & POLLHUP) { + /* + * If the event has been detached at cgroup removal, we + * can simply return knowing the other side will cleanup + * for us. + * + * We can't race against event freeing since the other + * side will require wqh->lock via remove_wait_queue(), + * which we hold. + */ + spin_lock(&memcg->event_list_lock); + if (!list_empty(&event->list)) { + list_del_init(&event->list); + /* + * We are in atomic context, but cgroup_event_remove() + * may sleep, so we have to call it in workqueue. + */ + schedule_work(&event->remove); + } + spin_unlock(&memcg->event_list_lock); + } + + return 0; +} + +static void memcg_event_ptable_queue_proc(struct file *file, + wait_queue_head_t *wqh, poll_table *pt) +{ + struct mem_cgroup_event *event = + container_of(pt, struct mem_cgroup_event, pt); + + event->wqh = wqh; + add_wait_queue(wqh, &event->wait); +} + +/* + * DO NOT USE IN NEW FILES. + * + * Parse input and register new cgroup event handler. + * + * Input must be in format '<event_fd> <control_fd> <args>'. + * Interpretation of args is defined by control file implementation. + */ +static ssize_t memcg_write_event_control(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct cgroup_subsys_state *css = of_css(of); + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + struct mem_cgroup_event *event; + struct cgroup_subsys_state *cfile_css; + unsigned int efd, cfd; + struct fd efile; + struct fd cfile; + const char *name; + char *endp; + int ret; + + buf = strstrip(buf); + + efd = simple_strtoul(buf, &endp, 10); + if (*endp != ' ') + return -EINVAL; + buf = endp + 1; + + cfd = simple_strtoul(buf, &endp, 10); + if ((*endp != ' ') && (*endp != '\0')) + return -EINVAL; + buf = endp + 1; + + event = kzalloc(sizeof(*event), GFP_KERNEL); + if (!event) + return -ENOMEM; + + event->memcg = memcg; + INIT_LIST_HEAD(&event->list); + init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc); + init_waitqueue_func_entry(&event->wait, memcg_event_wake); + INIT_WORK(&event->remove, memcg_event_remove); + + efile = fdget(efd); + if (!efile.file) { + ret = -EBADF; + goto out_kfree; + } + + event->eventfd = eventfd_ctx_fileget(efile.file); + if (IS_ERR(event->eventfd)) { + ret = PTR_ERR(event->eventfd); + goto out_put_efile; + } + + cfile = fdget(cfd); + if (!cfile.file) { + ret = -EBADF; + goto out_put_eventfd; + } + + /* the process need read permission on control file */ + /* AV: shouldn't we check that it's been opened for read instead? */ + ret = inode_permission(file_inode(cfile.file), MAY_READ); + if (ret < 0) + goto out_put_cfile; + + /* + * Determine the event callbacks and set them in @event. This used + * to be done via struct cftype but cgroup core no longer knows + * about these events. The following is crude but the whole thing + * is for compatibility anyway. + * + * DO NOT ADD NEW FILES. + */ + name = cfile.file->f_dentry->d_name.name; + + if (!strcmp(name, "memory.usage_in_bytes")) { + event->register_event = mem_cgroup_usage_register_event; + event->unregister_event = mem_cgroup_usage_unregister_event; + } else if (!strcmp(name, "memory.oom_control")) { + event->register_event = mem_cgroup_oom_register_event; + event->unregister_event = mem_cgroup_oom_unregister_event; + } else if (!strcmp(name, "memory.pressure_level")) { + event->register_event = vmpressure_register_event; + event->unregister_event = vmpressure_unregister_event; + } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) { + event->register_event = memsw_cgroup_usage_register_event; + event->unregister_event = memsw_cgroup_usage_unregister_event; + } else { + ret = -EINVAL; + goto out_put_cfile; + } + + /* + * Verify @cfile should belong to @css. Also, remaining events are + * automatically removed on cgroup destruction but the removal is + * asynchronous, so take an extra ref on @css. + */ + cfile_css = css_tryget_online_from_dir(cfile.file->f_dentry->d_parent, + &memory_cgrp_subsys); + ret = -EINVAL; + if (IS_ERR(cfile_css)) + goto out_put_cfile; + if (cfile_css != css) { + css_put(cfile_css); + goto out_put_cfile; + } + + ret = event->register_event(memcg, event->eventfd, buf); + if (ret) + goto out_put_css; + + efile.file->f_op->poll(efile.file, &event->pt); + + spin_lock(&memcg->event_list_lock); + list_add(&event->list, &memcg->event_list); + spin_unlock(&memcg->event_list_lock); + + fdput(cfile); + fdput(efile); + + return nbytes; + +out_put_css: + css_put(css); +out_put_cfile: + fdput(cfile); +out_put_eventfd: + eventfd_ctx_put(event->eventfd); +out_put_efile: + fdput(efile); +out_kfree: + kfree(event); + + return ret; +} + static struct cftype mem_cgroup_files[] = { { .name = "usage_in_bytes", .private = MEMFILE_PRIVATE(_MEM, RES_USAGE), - .read = mem_cgroup_read, - .register_event = mem_cgroup_usage_register_event, - .unregister_event = mem_cgroup_usage_unregister_event, + .read_u64 = mem_cgroup_read_u64, }, { .name = "max_usage_in_bytes", .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE), - .trigger = mem_cgroup_reset, - .read = mem_cgroup_read, + .write = mem_cgroup_reset, + .read_u64 = mem_cgroup_read_u64, }, { .name = "limit_in_bytes", .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT), - .write_string = mem_cgroup_write, - .read = mem_cgroup_read, + .write = mem_cgroup_write, + .read_u64 = mem_cgroup_read_u64, }, { .name = "soft_limit_in_bytes", .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT), - .write_string = mem_cgroup_write, - .read = mem_cgroup_read, + .write = mem_cgroup_write, + .read_u64 = mem_cgroup_read_u64, }, { .name = "failcnt", .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT), - .trigger = mem_cgroup_reset, - .read = mem_cgroup_read, + .write = mem_cgroup_reset, + .read_u64 = mem_cgroup_read_u64, }, { .name = "stat", - .read_seq_string = memcg_stat_show, + .seq_show = memcg_stat_show, }, { .name = "force_empty", - .trigger = mem_cgroup_force_empty_write, + .write = mem_cgroup_force_empty_write, }, { .name = "use_hierarchy", @@ -5940,6 +6012,12 @@ static struct cftype mem_cgroup_files[] = { .read_u64 = mem_cgroup_hierarchy_read, }, { + .name = "cgroup.event_control", /* XXX: for compat */ + .write = memcg_write_event_control, + .flags = CFTYPE_NO_PREFIX, + .mode = S_IWUGO, + }, + { .name = "swappiness", .read_u64 = mem_cgroup_swappiness_read, .write_u64 = mem_cgroup_swappiness_write, @@ -5951,51 +6029,47 @@ static struct cftype mem_cgroup_files[] = { }, { .name = "oom_control", - .read_map = mem_cgroup_oom_control_read, + .seq_show = mem_cgroup_oom_control_read, .write_u64 = mem_cgroup_oom_control_write, - .register_event = mem_cgroup_oom_register_event, - .unregister_event = mem_cgroup_oom_unregister_event, .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL), }, { .name = "pressure_level", - .register_event = vmpressure_register_event, - .unregister_event = vmpressure_unregister_event, }, #ifdef CONFIG_NUMA { .name = "numa_stat", - .read_seq_string = memcg_numa_stat_show, + .seq_show = memcg_numa_stat_show, }, #endif #ifdef CONFIG_MEMCG_KMEM { .name = "kmem.limit_in_bytes", .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT), - .write_string = mem_cgroup_write, - .read = mem_cgroup_read, + .write = mem_cgroup_write, + .read_u64 = mem_cgroup_read_u64, }, { .name = "kmem.usage_in_bytes", .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE), - .read = mem_cgroup_read, + .read_u64 = mem_cgroup_read_u64, }, { .name = "kmem.failcnt", .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT), - .trigger = mem_cgroup_reset, - .read = mem_cgroup_read, + .write = mem_cgroup_reset, + .read_u64 = mem_cgroup_read_u64, }, { .name = "kmem.max_usage_in_bytes", .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE), - .trigger = mem_cgroup_reset, - .read = mem_cgroup_read, + .write = mem_cgroup_reset, + .read_u64 = mem_cgroup_read_u64, }, #ifdef CONFIG_SLABINFO { .name = "kmem.slabinfo", - .read_seq_string = mem_cgroup_slabinfo_read, + .seq_show = mem_cgroup_slabinfo_read, }, #endif #endif @@ -6007,27 +6081,25 @@ static struct cftype memsw_cgroup_files[] = { { .name = "memsw.usage_in_bytes", .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), - .read = mem_cgroup_read, - .register_event = mem_cgroup_usage_register_event, - .unregister_event = mem_cgroup_usage_unregister_event, + .read_u64 = mem_cgroup_read_u64, }, { .name = "memsw.max_usage_in_bytes", .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE), - .trigger = mem_cgroup_reset, - .read = mem_cgroup_read, + .write = mem_cgroup_reset, + .read_u64 = mem_cgroup_read_u64, }, { .name = "memsw.limit_in_bytes", .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT), - .write_string = mem_cgroup_write, - .read = mem_cgroup_read, + .write = mem_cgroup_write, + .read_u64 = mem_cgroup_read_u64, }, { .name = "memsw.failcnt", .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT), - .trigger = mem_cgroup_reset, - .read = mem_cgroup_read, + .write = mem_cgroup_reset, + .read_u64 = mem_cgroup_read_u64, }, { }, /* terminate */ }; @@ -6058,26 +6130,24 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node) mz->on_tree = false; mz->memcg = memcg; } - memcg->info.nodeinfo[node] = pn; + memcg->nodeinfo[node] = pn; return 0; } static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node) { - kfree(memcg->info.nodeinfo[node]); + kfree(memcg->nodeinfo[node]); } static struct mem_cgroup *mem_cgroup_alloc(void) { struct mem_cgroup *memcg; - size_t size = memcg_size(); + size_t size; - /* Can be very big if nr_node_ids is very big */ - if (size < PAGE_SIZE) - memcg = kzalloc(size, GFP_KERNEL); - else - memcg = vzalloc(size); + size = sizeof(struct mem_cgroup); + size += nr_node_ids * sizeof(struct mem_cgroup_per_node *); + memcg = kzalloc(size, GFP_KERNEL); if (!memcg) return NULL; @@ -6088,10 +6158,7 @@ static struct mem_cgroup *mem_cgroup_alloc(void) return memcg; out_free: - if (size < PAGE_SIZE) - kfree(memcg); - else - vfree(memcg); + kfree(memcg); return NULL; } @@ -6109,10 +6176,8 @@ out_free: static void __mem_cgroup_free(struct mem_cgroup *memcg) { int node; - size_t size = memcg_size(); mem_cgroup_remove_from_trees(memcg); - free_css_id(&mem_cgroup_subsys, &memcg->css); for_each_node(node) free_mem_cgroup_per_zone_info(memcg, node); @@ -6131,53 +6196,7 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg) * the cgroup_lock. */ disarm_static_keys(memcg); - if (size < PAGE_SIZE) - kfree(memcg); - else - vfree(memcg); -} - - -/* - * Helpers for freeing a kmalloc()ed/vzalloc()ed mem_cgroup by RCU, - * but in process context. The work_freeing structure is overlaid - * on the rcu_freeing structure, which itself is overlaid on memsw. - */ -static void free_work(struct work_struct *work) -{ - struct mem_cgroup *memcg; - - memcg = container_of(work, struct mem_cgroup, work_freeing); - __mem_cgroup_free(memcg); -} - -static void free_rcu(struct rcu_head *rcu_head) -{ - struct mem_cgroup *memcg; - - memcg = container_of(rcu_head, struct mem_cgroup, rcu_freeing); - INIT_WORK(&memcg->work_freeing, free_work); - schedule_work(&memcg->work_freeing); -} - -static void mem_cgroup_get(struct mem_cgroup *memcg) -{ - atomic_inc(&memcg->refcnt); -} - -static void __mem_cgroup_put(struct mem_cgroup *memcg, int count) -{ - if (atomic_sub_and_test(count, &memcg->refcnt)) { - struct mem_cgroup *parent = parent_mem_cgroup(memcg); - call_rcu(&memcg->rcu_freeing, free_rcu); - if (parent) - mem_cgroup_put(parent); - } -} - -static void mem_cgroup_put(struct mem_cgroup *memcg) -{ - __mem_cgroup_put(memcg, 1); + kfree(memcg); } /* @@ -6215,7 +6234,7 @@ static void __init mem_cgroup_soft_limit_tree_init(void) } static struct cgroup_subsys_state * __ref -mem_cgroup_css_alloc(struct cgroup *cont) +mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) { struct mem_cgroup *memcg; long error = -ENOMEM; @@ -6230,7 +6249,7 @@ mem_cgroup_css_alloc(struct cgroup *cont) goto free_out; /* root ? */ - if (cont->parent == NULL) { + if (parent_css == NULL) { root_mem_cgroup = memcg; res_counter_init(&memcg->res, NULL); res_counter_init(&memcg->memsw, NULL); @@ -6239,11 +6258,12 @@ mem_cgroup_css_alloc(struct cgroup *cont) memcg->last_scanned_node = MAX_NUMNODES; INIT_LIST_HEAD(&memcg->oom_notify); - atomic_set(&memcg->refcnt, 1); memcg->move_charge_at_immigrate = 0; mutex_init(&memcg->thresholds_lock); spin_lock_init(&memcg->move_lock); vmpressure_init(&memcg->vmpressure); + INIT_LIST_HEAD(&memcg->event_list); + spin_lock_init(&memcg->event_list_lock); return &memcg->css; @@ -6253,17 +6273,18 @@ free_out: } static int -mem_cgroup_css_online(struct cgroup *cont) +mem_cgroup_css_online(struct cgroup_subsys_state *css) { - struct mem_cgroup *memcg, *parent; - int error = 0; + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + struct mem_cgroup *parent = mem_cgroup_from_css(css->parent); + + if (css->id > MEM_CGROUP_ID_MAX) + return -ENOSPC; - if (!cont->parent) + if (!parent) return 0; mutex_lock(&memcg_create_mutex); - memcg = mem_cgroup_from_cont(cont); - parent = mem_cgroup_from_cont(cont->parent); memcg->use_hierarchy = parent->use_hierarchy; memcg->oom_kill_disable = parent->oom_kill_disable; @@ -6275,12 +6296,9 @@ mem_cgroup_css_online(struct cgroup *cont) res_counter_init(&memcg->kmem, &parent->kmem); /* - * We increment refcnt of the parent to ensure that we can - * safely access it on res_counter_charge/uncharge. - * This refcnt will be decremented when freeing this - * mem_cgroup(see mem_cgroup_put). + * No need to take a reference to the parent because cgroup + * core guarantees its existence. */ - mem_cgroup_get(parent); } else { res_counter_init(&memcg->res, NULL); res_counter_init(&memcg->memsw, NULL); @@ -6291,22 +6309,11 @@ mem_cgroup_css_online(struct cgroup *cont) * unfortunate state in our controller. */ if (parent != root_mem_cgroup) - mem_cgroup_subsys.broken_hierarchy = true; + memory_cgrp_subsys.broken_hierarchy = true; } - - error = memcg_init_kmem(memcg, &mem_cgroup_subsys); mutex_unlock(&memcg_create_mutex); - if (error) { - /* - * We call put now because our (and parent's) refcnts - * are already in place. mem_cgroup_put() will internally - * call __mem_cgroup_free, so return directly - */ - mem_cgroup_put(memcg); - if (parent->use_hierarchy) - mem_cgroup_put(parent); - } - return error; + + return memcg_init_kmem(memcg, &memory_cgrp_subsys); } /* @@ -6317,32 +6324,91 @@ static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup *memcg) struct mem_cgroup *parent = memcg; while ((parent = parent_mem_cgroup(parent))) - atomic_inc(&parent->dead_count); + mem_cgroup_iter_invalidate(parent); /* * if the root memcg is not hierarchical we have to check it * explicitely. */ if (!root_mem_cgroup->use_hierarchy) - atomic_inc(&root_mem_cgroup->dead_count); + mem_cgroup_iter_invalidate(root_mem_cgroup); } -static void mem_cgroup_css_offline(struct cgroup *cont) +static void mem_cgroup_css_offline(struct cgroup_subsys_state *css) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + struct mem_cgroup_event *event, *tmp; + struct cgroup_subsys_state *iter; + + /* + * Unregister events and notify userspace. + * Notify userspace about cgroup removing only after rmdir of cgroup + * directory to avoid race between userspace and kernelspace. + */ + spin_lock(&memcg->event_list_lock); + list_for_each_entry_safe(event, tmp, &memcg->event_list, list) { + list_del_init(&event->list); + schedule_work(&event->remove); + } + spin_unlock(&memcg->event_list_lock); + + kmem_cgroup_css_offline(memcg); mem_cgroup_invalidate_reclaim_iterators(memcg); - mem_cgroup_reparent_charges(memcg); - mem_cgroup_destroy_all_caches(memcg); + + /* + * This requires that offlining is serialized. Right now that is + * guaranteed because css_killed_work_fn() holds the cgroup_mutex. + */ + css_for_each_descendant_post(iter, css) + mem_cgroup_reparent_charges(mem_cgroup_from_css(iter)); + + memcg_unregister_all_caches(memcg); + vmpressure_cleanup(&memcg->vmpressure); } -static void mem_cgroup_css_free(struct cgroup *cont) +static void mem_cgroup_css_free(struct cgroup_subsys_state *css) { - struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); - - kmem_cgroup_destroy(memcg); + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + /* + * XXX: css_offline() would be where we should reparent all + * memory to prepare the cgroup for destruction. However, + * memcg does not do css_tryget_online() and res_counter charging + * under the same RCU lock region, which means that charging + * could race with offlining. Offlining only happens to + * cgroups with no tasks in them but charges can show up + * without any tasks from the swapin path when the target + * memcg is looked up from the swapout record and not from the + * current task as it usually is. A race like this can leak + * charges and put pages with stale cgroup pointers into + * circulation: + * + * #0 #1 + * lookup_swap_cgroup_id() + * rcu_read_lock() + * mem_cgroup_lookup() + * css_tryget_online() + * rcu_read_unlock() + * disable css_tryget_online() + * call_rcu() + * offline_css() + * reparent_charges() + * res_counter_charge() + * css_put() + * css_free() + * pc->mem_cgroup = dead memcg + * add page to lru + * + * The bulk of the charges are still moved in offline_css() to + * avoid pinning a lot of pages in case a long-term reference + * like a swapout record is deferring the css_free() to long + * after offlining. But this makes sure we catch any charges + * made after offlining: + */ + mem_cgroup_reparent_charges(memcg); - mem_cgroup_put(memcg); + memcg_destroy_kmem(memcg); + __mem_cgroup_free(memcg); } #ifdef CONFIG_MMU @@ -6389,8 +6455,7 @@ one_by_one: batch_count = PRECHARGE_COUNT_AT_ONCE; cond_resched(); } - ret = __mem_cgroup_try_charge(NULL, - GFP_KERNEL, 1, &memcg, false); + ret = mem_cgroup_try_charge(memcg, GFP_KERNEL, 1, false); if (ret) /* mem_cgroup_clear_mc() will do uncharge later */ return ret; @@ -6494,16 +6559,20 @@ static struct page *mc_handle_file_pte(struct vm_area_struct *vma, pgoff = pte_to_pgoff(ptent); /* page is moved even if it's not RSS of this task(page-faulted). */ - page = find_get_page(mapping, pgoff); - #ifdef CONFIG_SWAP /* shmem/tmpfs may report page out on swap: account for that too. */ - if (radix_tree_exceptional_entry(page)) { - swp_entry_t swap = radix_to_swp_entry(page); - if (do_swap_account) - *entry = swap; - page = find_get_page(swap_address_space(swap), swap.val); - } + if (shmem_mapping(mapping)) { + page = find_get_entry(mapping, pgoff); + if (radix_tree_exceptional_entry(page)) { + swp_entry_t swp = radix_to_swp_entry(page); + if (do_swap_account) + *entry = swp; + page = find_get_page(swap_address_space(swp), swp.val); + } + } else + page = find_get_page(mapping, pgoff); +#else + page = find_get_page(mapping, pgoff); #endif return page; } @@ -6542,7 +6611,7 @@ static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma, } /* There is a swap entry and a page doesn't exist or isn't charged */ if (ent.val && !ret && - css_id(&mc.from->css) == lookup_swap_cgroup_id(ent)) { + mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) { ret = MC_TARGET_SWAP; if (target) target->ent = ent; @@ -6564,7 +6633,7 @@ static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma, enum mc_target_type ret = MC_TARGET_NONE; page = pmd_page(pmd); - VM_BUG_ON(!page || !PageHead(page)); + VM_BUG_ON_PAGE(!page || !PageHead(page), page); if (!move_anon()) return ret; pc = lookup_page_cgroup(page); @@ -6593,10 +6662,10 @@ static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, pte_t *pte; spinlock_t *ptl; - if (pmd_trans_huge_lock(pmd, vma) == 1) { + if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE) mc.precharge += HPAGE_PMD_NR; - spin_unlock(&vma->vm_mm->page_table_lock); + spin_unlock(ptl); return 0; } @@ -6651,6 +6720,7 @@ static void __mem_cgroup_clear_mc(void) { struct mem_cgroup *from = mc.from; struct mem_cgroup *to = mc.to; + int i; /* we must uncharge all the leftover precharges from mc.to */ if (mc.precharge) { @@ -6671,7 +6741,9 @@ static void __mem_cgroup_clear_mc(void) if (!mem_cgroup_is_root(mc.from)) res_counter_uncharge(&mc.from->memsw, PAGE_SIZE * mc.moved_swap); - __mem_cgroup_put(mc.from, mc.moved_swap); + + for (i = 0; i < mc.moved_swap; i++) + css_put(&mc.from->css); if (!mem_cgroup_is_root(mc.to)) { /* @@ -6681,7 +6753,7 @@ static void __mem_cgroup_clear_mc(void) res_counter_uncharge(&mc.to->res, PAGE_SIZE * mc.moved_swap); } - /* we've already done mem_cgroup_get(mc.to) */ + /* we've already done css_get(mc.to) */ mc.moved_swap = 0; } memcg_oom_recover(from); @@ -6706,12 +6778,12 @@ static void mem_cgroup_clear_mc(void) mem_cgroup_end_move(from); } -static int mem_cgroup_can_attach(struct cgroup *cgroup, +static int mem_cgroup_can_attach(struct cgroup_subsys_state *css, struct cgroup_taskset *tset) { struct task_struct *p = cgroup_taskset_first(tset); int ret = 0; - struct mem_cgroup *memcg = mem_cgroup_from_cont(cgroup); + struct mem_cgroup *memcg = mem_cgroup_from_css(css); unsigned long move_charge_at_immigrate; /* @@ -6753,7 +6825,7 @@ static int mem_cgroup_can_attach(struct cgroup *cgroup, return ret; } -static void mem_cgroup_cancel_attach(struct cgroup *cgroup, +static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css, struct cgroup_taskset *tset) { mem_cgroup_clear_mc(); @@ -6782,9 +6854,9 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, * to be unlocked in __split_huge_page_splitting(), where the main * part of thp split is not executed yet. */ - if (pmd_trans_huge_lock(pmd, vma) == 1) { + if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { if (mc.precharge < HPAGE_PMD_NR) { - spin_unlock(&vma->vm_mm->page_table_lock); + spin_unlock(ptl); return 0; } target_type = get_mctgt_type_thp(vma, addr, *pmd, &target); @@ -6801,7 +6873,7 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, } put_page(page); } - spin_unlock(&vma->vm_mm->page_table_lock); + spin_unlock(ptl); return 0; } @@ -6901,7 +6973,7 @@ retry: up_read(&mm->mmap_sem); } -static void mem_cgroup_move_task(struct cgroup *cont, +static void mem_cgroup_move_task(struct cgroup_subsys_state *css, struct cgroup_taskset *tset) { struct task_struct *p = cgroup_taskset_first(tset); @@ -6916,16 +6988,16 @@ static void mem_cgroup_move_task(struct cgroup *cont, mem_cgroup_clear_mc(); } #else /* !CONFIG_MMU */ -static int mem_cgroup_can_attach(struct cgroup *cgroup, +static int mem_cgroup_can_attach(struct cgroup_subsys_state *css, struct cgroup_taskset *tset) { return 0; } -static void mem_cgroup_cancel_attach(struct cgroup *cgroup, +static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css, struct cgroup_taskset *tset) { } -static void mem_cgroup_move_task(struct cgroup *cont, +static void mem_cgroup_move_task(struct cgroup_subsys_state *css, struct cgroup_taskset *tset) { } @@ -6935,20 +7007,18 @@ static void mem_cgroup_move_task(struct cgroup *cont, * Cgroup retains root cgroups across [un]mount cycles making it necessary * to verify sane_behavior flag on each mount attempt. */ -static void mem_cgroup_bind(struct cgroup *root) +static void mem_cgroup_bind(struct cgroup_subsys_state *root_css) { /* * use_hierarchy is forced with sane_behavior. cgroup core * guarantees that @root doesn't have any children, so turning it * on for the root memcg is enough. */ - if (cgroup_sane_behavior(root)) - mem_cgroup_from_cont(root)->use_hierarchy = true; + if (cgroup_sane_behavior(root_css->cgroup)) + mem_cgroup_from_css(root_css)->use_hierarchy = true; } -struct cgroup_subsys mem_cgroup_subsys = { - .name = "memory", - .subsys_id = mem_cgroup_subsys_id, +struct cgroup_subsys memory_cgrp_subsys = { .css_alloc = mem_cgroup_css_alloc, .css_online = mem_cgroup_css_online, .css_offline = mem_cgroup_css_offline, @@ -6959,13 +7029,11 @@ struct cgroup_subsys mem_cgroup_subsys = { .bind = mem_cgroup_bind, .base_cftypes = mem_cgroup_files, .early_init = 0, - .use_id = 1, }; #ifdef CONFIG_MEMCG_SWAP static int __init enable_swap_account(char *s) { - /* consider enabled if no parameter or 1 is given */ if (!strcmp(s, "1")) really_do_swap_account = 1; else if (!strcmp(s, "0")) @@ -6976,7 +7044,7 @@ __setup("swapaccount=", enable_swap_account); static void __init memsw_file_init(void) { - WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys, memsw_cgroup_files)); + WARN_ON(cgroup_add_cftypes(&memory_cgrp_subsys, memsw_cgroup_files)); } static void __init enable_swap_cgroup(void) |