diff options
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 4143 |
1 files changed, 2484 insertions, 1659 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 3a24e3b619f5..61932c9215e7 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -20,6 +20,9 @@ * Lockless page tracking & accounting * Unified hierarchy configuration model * Copyright (C) 2015 Red Hat, Inc., Johannes Weiner + * + * Per memcg lru locking + * Copyright (C) 2020 Alibaba, Inc, Alex Shi */ #include <linux/page_counter.h> @@ -50,19 +53,23 @@ #include <linux/fs.h> #include <linux/seq_file.h> #include <linux/vmpressure.h> +#include <linux/memremap.h> #include <linux/mm_inline.h> #include <linux/swap_cgroup.h> #include <linux/cpu.h> #include <linux/oom.h> #include <linux/lockdep.h> #include <linux/file.h> -#include <linux/tracehook.h> +#include <linux/resume_user_mode.h> #include <linux/psi.h> #include <linux/seq_buf.h> +#include <linux/sched/isolation.h> +#include <linux/kmemleak.h> #include "internal.h" #include <net/sock.h> #include <net/ip.h> #include "slab.h" +#include "swap.h" #include <linux/uaccess.h> @@ -75,19 +82,16 @@ struct mem_cgroup *root_mem_cgroup __read_mostly; /* Active memory cgroup to use from an interrupt context */ DEFINE_PER_CPU(struct mem_cgroup *, int_active_memcg); +EXPORT_PER_CPU_SYMBOL_GPL(int_active_memcg); /* Socket memory accounting disabled? */ -static bool cgroup_memory_nosocket; +static bool cgroup_memory_nosocket __ro_after_init; /* Kernel memory accounting disabled? */ -static bool cgroup_memory_nokmem; +static bool cgroup_memory_nokmem __ro_after_init; -/* Whether the swap controller is active */ -#ifdef CONFIG_MEMCG_SWAP -bool cgroup_memory_noswap __read_mostly; -#else -#define cgroup_memory_noswap 1 -#endif +/* BPF memory accounting disabled? */ +static bool cgroup_memory_nobpf __ro_after_init; #ifdef CONFIG_CGROUP_WRITEBACK static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq); @@ -96,7 +100,7 @@ static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq); /* Whether legacy memory+swap accounting is active */ static bool do_memsw_account(void) { - return !cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_noswap; + return !cgroup_subsys_on_dfl(memory_cgrp_subsys); } #define THRESHOLDS_EVENTS_TARGET 128 @@ -194,7 +198,7 @@ static struct move_charge_struct { }; /* - * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft + * Maximum loops in mem_cgroup_soft_reclaim(), used for soft * limit reclaim to prevent infinite loops, if they ever occur. */ #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100 @@ -204,7 +208,6 @@ static struct move_charge_struct { enum res_type { _MEM, _MEMSWAP, - _OOM_TYPE, _KMEM, _TCP, }; @@ -212,8 +215,6 @@ enum res_type { #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val)) #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff) #define MEMFILE_ATTR(val) ((val) & 0xffff) -/* Used for OOM nofiier */ -#define OOM_CONTROL (0) /* * Iteration constructs for visiting all cgroups (under a tree). If @@ -230,7 +231,7 @@ enum res_type { iter != NULL; \ iter = mem_cgroup_iter(NULL, iter, NULL)) -static inline bool should_force_charge(void) +static inline bool task_is_dying(void) { return tsk_is_oom_victim(current) || fatal_signal_pending(current) || (current->flags & PF_EXITING); @@ -244,18 +245,28 @@ struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg) return &memcg->vmpressure; } -struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr) +struct mem_cgroup *vmpressure_to_memcg(struct vmpressure *vmpr) { - return &container_of(vmpr, struct mem_cgroup, vmpressure)->css; + return container_of(vmpr, struct mem_cgroup, vmpressure); } +#define CURRENT_OBJCG_UPDATE_BIT 0 +#define CURRENT_OBJCG_UPDATE_FLAG (1UL << CURRENT_OBJCG_UPDATE_BIT) + #ifdef CONFIG_MEMCG_KMEM -extern spinlock_t css_set_lock; +static DEFINE_SPINLOCK(objcg_lock); + +bool mem_cgroup_kmem_disabled(void) +{ + return cgroup_memory_nokmem; +} + +static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg, + unsigned int nr_pages); static void obj_cgroup_release(struct percpu_ref *ref) { struct obj_cgroup *objcg = container_of(ref, struct obj_cgroup, refcnt); - struct mem_cgroup *memcg; unsigned int nr_bytes; unsigned int nr_pages; unsigned long flags; @@ -284,13 +295,12 @@ static void obj_cgroup_release(struct percpu_ref *ref) WARN_ON_ONCE(nr_bytes & (PAGE_SIZE - 1)); nr_pages = nr_bytes >> PAGE_SHIFT; - spin_lock_irqsave(&css_set_lock, flags); - memcg = obj_cgroup_memcg(objcg); if (nr_pages) - __memcg_kmem_uncharge(memcg, nr_pages); + obj_cgroup_uncharge_pages(objcg, nr_pages); + + spin_lock_irqsave(&objcg_lock, flags); list_del(&objcg->list); - mem_cgroup_put(memcg); - spin_unlock_irqrestore(&css_set_lock, flags); + spin_unlock_irqrestore(&objcg_lock, flags); percpu_ref_exit(ref); kfree_rcu(objcg, rcu); @@ -322,218 +332,48 @@ static void memcg_reparent_objcgs(struct mem_cgroup *memcg, objcg = rcu_replace_pointer(memcg->objcg, NULL, true); - spin_lock_irq(&css_set_lock); - - /* Move active objcg to the parent's list */ - xchg(&objcg->memcg, parent); - css_get(&parent->css); - list_add(&objcg->list, &parent->objcg_list); + spin_lock_irq(&objcg_lock); - /* Move already reparented objcgs to the parent's list */ - list_for_each_entry(iter, &memcg->objcg_list, list) { - css_get(&parent->css); - xchg(&iter->memcg, parent); - css_put(&memcg->css); - } + /* 1) Ready to reparent active objcg. */ + list_add(&objcg->list, &memcg->objcg_list); + /* 2) Reparent active objcg and already reparented objcgs to parent. */ + list_for_each_entry(iter, &memcg->objcg_list, list) + WRITE_ONCE(iter->memcg, parent); + /* 3) Move already reparented objcgs to the parent's list */ list_splice(&memcg->objcg_list, &parent->objcg_list); - spin_unlock_irq(&css_set_lock); + spin_unlock_irq(&objcg_lock); percpu_ref_kill(&objcg->refcnt); } /* - * This will be used as a shrinker list's index. - * 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_nr_cache_ids. It - * will double each time we have to increase it. - */ -static DEFINE_IDA(memcg_cache_ida); -int memcg_nr_cache_ids; - -/* Protects memcg_nr_cache_ids */ -static DECLARE_RWSEM(memcg_cache_ids_sem); - -void memcg_get_cache_ids(void) -{ - down_read(&memcg_cache_ids_sem); -} - -void memcg_put_cache_ids(void) -{ - up_read(&memcg_cache_ids_sem); -} - -/* - * MIN_SIZE is different than 1, because we would like to avoid going through - * the alloc/free process all the time. In a small machine, 4 kmem-limited - * 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 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 - * 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 MEM_CGROUP_ID_MAX - -/* * A lot of the calls to the cache allocation functions are expected to be * inlined by the compiler. Since the calls to memcg_slab_pre_alloc_hook() are * conditional to this static branch, we'll have to allow modules that does * kmem_cache_alloc and the such to see this symbol as well */ -DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key); -EXPORT_SYMBOL(memcg_kmem_enabled_key); -#endif - -static int memcg_shrinker_map_size; -static DEFINE_MUTEX(memcg_shrinker_map_mutex); - -static void memcg_free_shrinker_map_rcu(struct rcu_head *head) -{ - kvfree(container_of(head, struct memcg_shrinker_map, rcu)); -} +DEFINE_STATIC_KEY_FALSE(memcg_kmem_online_key); +EXPORT_SYMBOL(memcg_kmem_online_key); -static int memcg_expand_one_shrinker_map(struct mem_cgroup *memcg, - int size, int old_size) -{ - struct memcg_shrinker_map *new, *old; - int nid; - - lockdep_assert_held(&memcg_shrinker_map_mutex); - - for_each_node(nid) { - old = rcu_dereference_protected( - mem_cgroup_nodeinfo(memcg, nid)->shrinker_map, true); - /* Not yet online memcg */ - if (!old) - return 0; - - new = kvmalloc_node(sizeof(*new) + size, GFP_KERNEL, nid); - if (!new) - return -ENOMEM; - - /* Set all old bits, clear all new bits */ - memset(new->map, (int)0xff, old_size); - memset((void *)new->map + old_size, 0, size - old_size); - - rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_map, new); - call_rcu(&old->rcu, memcg_free_shrinker_map_rcu); - } - - return 0; -} - -static void memcg_free_shrinker_maps(struct mem_cgroup *memcg) -{ - struct mem_cgroup_per_node *pn; - struct memcg_shrinker_map *map; - int nid; - - if (mem_cgroup_is_root(memcg)) - return; - - for_each_node(nid) { - pn = mem_cgroup_nodeinfo(memcg, nid); - map = rcu_dereference_protected(pn->shrinker_map, true); - if (map) - kvfree(map); - rcu_assign_pointer(pn->shrinker_map, NULL); - } -} - -static int memcg_alloc_shrinker_maps(struct mem_cgroup *memcg) -{ - struct memcg_shrinker_map *map; - int nid, size, ret = 0; - - if (mem_cgroup_is_root(memcg)) - return 0; - - mutex_lock(&memcg_shrinker_map_mutex); - size = memcg_shrinker_map_size; - for_each_node(nid) { - map = kvzalloc_node(sizeof(*map) + size, GFP_KERNEL, nid); - if (!map) { - memcg_free_shrinker_maps(memcg); - ret = -ENOMEM; - break; - } - rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_map, map); - } - mutex_unlock(&memcg_shrinker_map_mutex); - - return ret; -} - -int memcg_expand_shrinker_maps(int new_id) -{ - int size, old_size, ret = 0; - struct mem_cgroup *memcg; - - size = DIV_ROUND_UP(new_id + 1, BITS_PER_LONG) * sizeof(unsigned long); - old_size = memcg_shrinker_map_size; - if (size <= old_size) - return 0; - - mutex_lock(&memcg_shrinker_map_mutex); - if (!root_mem_cgroup) - goto unlock; - - for_each_mem_cgroup(memcg) { - if (mem_cgroup_is_root(memcg)) - continue; - ret = memcg_expand_one_shrinker_map(memcg, size, old_size); - if (ret) { - mem_cgroup_iter_break(NULL, memcg); - goto unlock; - } - } -unlock: - if (!ret) - memcg_shrinker_map_size = size; - mutex_unlock(&memcg_shrinker_map_mutex); - return ret; -} - -void memcg_set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id) -{ - if (shrinker_id >= 0 && memcg && !mem_cgroup_is_root(memcg)) { - struct memcg_shrinker_map *map; - - rcu_read_lock(); - map = rcu_dereference(memcg->nodeinfo[nid]->shrinker_map); - /* Pairs with smp mb in shrink_slab() */ - smp_mb__before_atomic(); - set_bit(shrinker_id, map->map); - rcu_read_unlock(); - } -} +DEFINE_STATIC_KEY_FALSE(memcg_bpf_enabled_key); +EXPORT_SYMBOL(memcg_bpf_enabled_key); +#endif /** - * mem_cgroup_css_from_page - css of the memcg associated with a page - * @page: page of interest + * mem_cgroup_css_from_folio - css of the memcg associated with a folio + * @folio: folio of interest * * If memcg is bound to the default hierarchy, css of the memcg associated - * with @page is returned. The returned css remains associated with @page + * with @folio is returned. The returned css remains associated with @folio * until it is released. * * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup * is returned. */ -struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page) +struct cgroup_subsys_state *mem_cgroup_css_from_folio(struct folio *folio) { - struct mem_cgroup *memcg; - - memcg = page->mem_cgroup; + struct mem_cgroup *memcg = folio_memcg(folio); if (!memcg || !cgroup_subsys_on_dfl(memory_cgrp_subsys)) memcg = root_mem_cgroup; @@ -560,16 +400,8 @@ ino_t page_cgroup_ino(struct page *page) unsigned long ino = 0; rcu_read_lock(); - memcg = page->mem_cgroup; - - /* - * The lowest bit set means that memcg isn't a valid - * memcg pointer, but a obj_cgroups pointer. - * In this case the page is shared and doesn't belong - * to any specific memory cgroup. - */ - if ((unsigned long) memcg & 0x1UL) - memcg = NULL; + /* page_folio() is racy here, but the entire function is racy anyway */ + memcg = folio_memcg_check(page_folio(page)); while (memcg && !(memcg->css.flags & CSS_ONLINE)) memcg = parent_mem_cgroup(memcg); @@ -579,28 +411,6 @@ ino_t page_cgroup_ino(struct page *page) return ino; } -static struct mem_cgroup_per_node * -mem_cgroup_page_nodeinfo(struct mem_cgroup *memcg, struct page *page) -{ - int nid = page_to_nid(page); - - return memcg->nodeinfo[nid]; -} - -static struct mem_cgroup_tree_per_node * -soft_limit_tree_node(int nid) -{ - return soft_limit_tree.rb_tree_per_node[nid]; -} - -static struct mem_cgroup_tree_per_node * -soft_limit_tree_from_page(struct page *page) -{ - int nid = page_to_nid(page); - - return soft_limit_tree.rb_tree_per_node[nid]; -} - static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz, struct mem_cgroup_tree_per_node *mctz, unsigned long new_usage_in_excess) @@ -623,14 +433,9 @@ static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz, if (mz->usage_in_excess < mz_node->usage_in_excess) { p = &(*p)->rb_left; rightmost = false; - } - - /* - * We can't avoid mem cgroups that are over their soft - * limit by the same amount - */ - else if (mz->usage_in_excess >= mz_node->usage_in_excess) + } else { p = &(*p)->rb_right; + } } if (rightmost) @@ -676,13 +481,19 @@ static unsigned long soft_limit_excess(struct mem_cgroup *memcg) return excess; } -static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page) +static void mem_cgroup_update_tree(struct mem_cgroup *memcg, int nid) { unsigned long excess; struct mem_cgroup_per_node *mz; struct mem_cgroup_tree_per_node *mctz; - mctz = soft_limit_tree_from_page(page); + if (lru_gen_enabled()) { + if (soft_limit_excess(memcg)) + lru_gen_soft_reclaim(memcg, nid); + return; + } + + mctz = soft_limit_tree.rb_tree_per_node[nid]; if (!mctz) return; /* @@ -690,7 +501,7 @@ static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page) * because their event counter is not touched. */ for (; memcg; memcg = parent_mem_cgroup(memcg)) { - mz = mem_cgroup_page_nodeinfo(memcg, page); + mz = memcg->nodeinfo[nid]; excess = soft_limit_excess(memcg); /* * We have to update the tree if mz is on RB-tree or @@ -720,8 +531,8 @@ static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg) int nid; for_each_node(nid) { - mz = mem_cgroup_nodeinfo(memcg, nid); - mctz = soft_limit_tree_node(nid); + mz = memcg->nodeinfo[nid]; + mctz = soft_limit_tree.rb_tree_per_node[nid]; if (mctz) mem_cgroup_remove_exceeded(mz, mctz); } @@ -763,6 +574,240 @@ mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz) return mz; } +/* Subset of vm_event_item to report for memcg event stats */ +static const unsigned int memcg_vm_event_stat[] = { + PGPGIN, + PGPGOUT, + PGSCAN_KSWAPD, + PGSCAN_DIRECT, + PGSCAN_KHUGEPAGED, + PGSTEAL_KSWAPD, + PGSTEAL_DIRECT, + PGSTEAL_KHUGEPAGED, + PGFAULT, + PGMAJFAULT, + PGREFILL, + PGACTIVATE, + PGDEACTIVATE, + PGLAZYFREE, + PGLAZYFREED, +#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP) + ZSWPIN, + ZSWPOUT, + ZSWPWB, +#endif +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + THP_FAULT_ALLOC, + THP_COLLAPSE_ALLOC, + THP_SWPOUT, + THP_SWPOUT_FALLBACK, +#endif +}; + +#define NR_MEMCG_EVENTS ARRAY_SIZE(memcg_vm_event_stat) +static int mem_cgroup_events_index[NR_VM_EVENT_ITEMS] __read_mostly; + +static void init_memcg_events(void) +{ + int i; + + for (i = 0; i < NR_MEMCG_EVENTS; ++i) + mem_cgroup_events_index[memcg_vm_event_stat[i]] = i + 1; +} + +static inline int memcg_events_index(enum vm_event_item idx) +{ + return mem_cgroup_events_index[idx] - 1; +} + +struct memcg_vmstats_percpu { + /* Stats updates since the last flush */ + unsigned int stats_updates; + + /* Cached pointers for fast iteration in memcg_rstat_updated() */ + struct memcg_vmstats_percpu *parent; + struct memcg_vmstats *vmstats; + + /* The above should fit a single cacheline for memcg_rstat_updated() */ + + /* Local (CPU and cgroup) page state & events */ + long state[MEMCG_NR_STAT]; + unsigned long events[NR_MEMCG_EVENTS]; + + /* Delta calculation for lockless upward propagation */ + long state_prev[MEMCG_NR_STAT]; + unsigned long events_prev[NR_MEMCG_EVENTS]; + + /* Cgroup1: threshold notifications & softlimit tree updates */ + unsigned long nr_page_events; + unsigned long targets[MEM_CGROUP_NTARGETS]; +} ____cacheline_aligned; + +struct memcg_vmstats { + /* Aggregated (CPU and subtree) page state & events */ + long state[MEMCG_NR_STAT]; + unsigned long events[NR_MEMCG_EVENTS]; + + /* Non-hierarchical (CPU aggregated) page state & events */ + long state_local[MEMCG_NR_STAT]; + unsigned long events_local[NR_MEMCG_EVENTS]; + + /* Pending child counts during tree propagation */ + long state_pending[MEMCG_NR_STAT]; + unsigned long events_pending[NR_MEMCG_EVENTS]; + + /* Stats updates since the last flush */ + atomic64_t stats_updates; +}; + +/* + * memcg and lruvec stats flushing + * + * Many codepaths leading to stats update or read are performance sensitive and + * adding stats flushing in such codepaths is not desirable. So, to optimize the + * flushing the kernel does: + * + * 1) Periodically and asynchronously flush the stats every 2 seconds to not let + * rstat update tree grow unbounded. + * + * 2) Flush the stats synchronously on reader side only when there are more than + * (MEMCG_CHARGE_BATCH * nr_cpus) update events. Though this optimization + * will let stats be out of sync by atmost (MEMCG_CHARGE_BATCH * nr_cpus) but + * only for 2 seconds due to (1). + */ +static void flush_memcg_stats_dwork(struct work_struct *w); +static DECLARE_DEFERRABLE_WORK(stats_flush_dwork, flush_memcg_stats_dwork); +static u64 flush_last_time; + +#define FLUSH_TIME (2UL*HZ) + +/* + * Accessors to ensure that preemption is disabled on PREEMPT_RT because it can + * not rely on this as part of an acquired spinlock_t lock. These functions are + * never used in hardirq context on PREEMPT_RT and therefore disabling preemtion + * is sufficient. + */ +static void memcg_stats_lock(void) +{ + preempt_disable_nested(); + VM_WARN_ON_IRQS_ENABLED(); +} + +static void __memcg_stats_lock(void) +{ + preempt_disable_nested(); +} + +static void memcg_stats_unlock(void) +{ + preempt_enable_nested(); +} + + +static bool memcg_vmstats_needs_flush(struct memcg_vmstats *vmstats) +{ + return atomic64_read(&vmstats->stats_updates) > + MEMCG_CHARGE_BATCH * num_online_cpus(); +} + +static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val) +{ + struct memcg_vmstats_percpu *statc; + int cpu = smp_processor_id(); + + if (!val) + return; + + cgroup_rstat_updated(memcg->css.cgroup, cpu); + statc = this_cpu_ptr(memcg->vmstats_percpu); + for (; statc; statc = statc->parent) { + statc->stats_updates += abs(val); + if (statc->stats_updates < MEMCG_CHARGE_BATCH) + continue; + + /* + * If @memcg is already flush-able, increasing stats_updates is + * redundant. Avoid the overhead of the atomic update. + */ + if (!memcg_vmstats_needs_flush(statc->vmstats)) + atomic64_add(statc->stats_updates, + &statc->vmstats->stats_updates); + statc->stats_updates = 0; + } +} + +static void do_flush_stats(struct mem_cgroup *memcg) +{ + if (mem_cgroup_is_root(memcg)) + WRITE_ONCE(flush_last_time, jiffies_64); + + cgroup_rstat_flush(memcg->css.cgroup); +} + +/* + * mem_cgroup_flush_stats - flush the stats of a memory cgroup subtree + * @memcg: root of the subtree to flush + * + * Flushing is serialized by the underlying global rstat lock. There is also a + * minimum amount of work to be done even if there are no stat updates to flush. + * Hence, we only flush the stats if the updates delta exceeds a threshold. This + * avoids unnecessary work and contention on the underlying lock. + */ +void mem_cgroup_flush_stats(struct mem_cgroup *memcg) +{ + if (mem_cgroup_disabled()) + return; + + if (!memcg) + memcg = root_mem_cgroup; + + if (memcg_vmstats_needs_flush(memcg->vmstats)) + do_flush_stats(memcg); +} + +void mem_cgroup_flush_stats_ratelimited(struct mem_cgroup *memcg) +{ + /* Only flush if the periodic flusher is one full cycle late */ + if (time_after64(jiffies_64, READ_ONCE(flush_last_time) + 2*FLUSH_TIME)) + mem_cgroup_flush_stats(memcg); +} + +static void flush_memcg_stats_dwork(struct work_struct *w) +{ + /* + * Deliberately ignore memcg_vmstats_needs_flush() here so that flushing + * in latency-sensitive paths is as cheap as possible. + */ + do_flush_stats(root_mem_cgroup); + queue_delayed_work(system_unbound_wq, &stats_flush_dwork, FLUSH_TIME); +} + +unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx) +{ + long x = READ_ONCE(memcg->vmstats->state[idx]); +#ifdef CONFIG_SMP + if (x < 0) + x = 0; +#endif + return x; +} + +static int memcg_page_state_unit(int item); + +/* + * Normalize the value passed into memcg_rstat_updated() to be in pages. Round + * up non-zero sub-page updates to 1 page as zero page updates are ignored. + */ +static int memcg_state_val_in_pages(int idx, int val) +{ + int unit = memcg_page_state_unit(idx); + + if (!val || unit == PAGE_SIZE) + return val; + else + return max(val * unit / PAGE_SIZE, 1UL); +} + /** * __mod_memcg_state - update cgroup memory statistics * @memcg: the memory cgroup @@ -771,39 +816,23 @@ mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz) */ void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val) { - long x, threshold = MEMCG_CHARGE_BATCH; - if (mem_cgroup_disabled()) return; - if (memcg_stat_item_in_bytes(idx)) - threshold <<= PAGE_SHIFT; - - x = val + __this_cpu_read(memcg->vmstats_percpu->stat[idx]); - if (unlikely(abs(x) > threshold)) { - struct mem_cgroup *mi; - - /* - * Batch local counters to keep them in sync with - * the hierarchical ones. - */ - __this_cpu_add(memcg->vmstats_local->stat[idx], x); - for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) - atomic_long_add(x, &mi->vmstats[idx]); - x = 0; - } - __this_cpu_write(memcg->vmstats_percpu->stat[idx], x); + __this_cpu_add(memcg->vmstats_percpu->state[idx], val); + memcg_rstat_updated(memcg, memcg_state_val_in_pages(idx, val)); } -static struct mem_cgroup_per_node * -parent_nodeinfo(struct mem_cgroup_per_node *pn, int nid) +/* idx can be of type enum memcg_stat_item or node_stat_item. */ +static unsigned long memcg_page_state_local(struct mem_cgroup *memcg, int idx) { - struct mem_cgroup *parent; + long x = READ_ONCE(memcg->vmstats->state_local[idx]); - parent = parent_mem_cgroup(pn->memcg); - if (!parent) - return NULL; - return mem_cgroup_nodeinfo(parent, nid); +#ifdef CONFIG_SMP + if (x < 0) + x = 0; +#endif + return x; } void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx, @@ -811,30 +840,39 @@ void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx, { struct mem_cgroup_per_node *pn; struct mem_cgroup *memcg; - long x, threshold = MEMCG_CHARGE_BATCH; pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec); memcg = pn->memcg; + /* + * The caller from rmap relies on disabled preemption because they never + * update their counter from in-interrupt context. For these two + * counters we check that the update is never performed from an + * interrupt context while other caller need to have disabled interrupt. + */ + __memcg_stats_lock(); + if (IS_ENABLED(CONFIG_DEBUG_VM)) { + switch (idx) { + case NR_ANON_MAPPED: + case NR_FILE_MAPPED: + case NR_ANON_THPS: + case NR_SHMEM_PMDMAPPED: + case NR_FILE_PMDMAPPED: + WARN_ON_ONCE(!in_task()); + break; + default: + VM_WARN_ON_IRQS_ENABLED(); + } + } + /* Update memcg */ - __mod_memcg_state(memcg, idx, val); + __this_cpu_add(memcg->vmstats_percpu->state[idx], val); /* Update lruvec */ - __this_cpu_add(pn->lruvec_stat_local->count[idx], val); - - if (vmstat_item_in_bytes(idx)) - threshold <<= PAGE_SHIFT; + __this_cpu_add(pn->lruvec_stats_percpu->state[idx], val); - x = val + __this_cpu_read(pn->lruvec_stat_cpu->count[idx]); - if (unlikely(abs(x) > threshold)) { - pg_data_t *pgdat = lruvec_pgdat(lruvec); - struct mem_cgroup_per_node *pi; - - for (pi = pn; pi; pi = parent_nodeinfo(pi, pgdat->node_id)) - atomic_long_add(x, &pi->lruvec_stat[idx]); - x = 0; - } - __this_cpu_write(pn->lruvec_stat_cpu->count[idx], x); + memcg_rstat_updated(memcg, memcg_state_val_in_pages(idx, val)); + memcg_stats_unlock(); } /** @@ -858,33 +896,49 @@ void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx, __mod_memcg_lruvec_state(lruvec, idx, val); } -void __mod_lruvec_slab_state(void *p, enum node_stat_item idx, int val) +void __lruvec_stat_mod_folio(struct folio *folio, enum node_stat_item idx, + int val) { - pg_data_t *pgdat = page_pgdat(virt_to_page(p)); struct mem_cgroup *memcg; + pg_data_t *pgdat = folio_pgdat(folio); struct lruvec *lruvec; rcu_read_lock(); - memcg = mem_cgroup_from_obj(p); - + memcg = folio_memcg(folio); /* Untracked pages have no memcg, no lruvec. Update only the node */ - if (!memcg || memcg == root_mem_cgroup) { + if (!memcg) { + rcu_read_unlock(); __mod_node_page_state(pgdat, idx, val); - } else { - lruvec = mem_cgroup_lruvec(memcg, pgdat); - __mod_lruvec_state(lruvec, idx, val); + return; } + + lruvec = mem_cgroup_lruvec(memcg, pgdat); + __mod_lruvec_state(lruvec, idx, val); rcu_read_unlock(); } +EXPORT_SYMBOL(__lruvec_stat_mod_folio); -void mod_memcg_obj_state(void *p, int idx, int val) +void __mod_lruvec_kmem_state(void *p, enum node_stat_item idx, int val) { + pg_data_t *pgdat = page_pgdat(virt_to_page(p)); struct mem_cgroup *memcg; + struct lruvec *lruvec; rcu_read_lock(); - memcg = mem_cgroup_from_obj(p); - if (memcg) - mod_memcg_state(memcg, idx, val); + memcg = mem_cgroup_from_slab_obj(p); + + /* + * Untracked pages have no memcg, no lruvec. Update only the + * node. If we reparent the slab objects to the root memcg, + * when we free the slab object, we need to update the per-memcg + * vmstats to keep it correct for the root memcg. + */ + if (!memcg) { + __mod_node_page_state(pgdat, idx, val); + } else { + lruvec = mem_cgroup_lruvec(memcg, pgdat); + __mod_lruvec_state(lruvec, idx, val); + } rcu_read_unlock(); } @@ -892,49 +946,42 @@ void mod_memcg_obj_state(void *p, int idx, int val) * __count_memcg_events - account VM events in a cgroup * @memcg: the memory cgroup * @idx: the event item - * @count: the number of events that occured + * @count: the number of events that occurred */ void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx, unsigned long count) { - unsigned long x; + int index = memcg_events_index(idx); - if (mem_cgroup_disabled()) + if (mem_cgroup_disabled() || index < 0) return; - x = count + __this_cpu_read(memcg->vmstats_percpu->events[idx]); - if (unlikely(x > MEMCG_CHARGE_BATCH)) { - struct mem_cgroup *mi; - - /* - * Batch local counters to keep them in sync with - * the hierarchical ones. - */ - __this_cpu_add(memcg->vmstats_local->events[idx], x); - for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) - atomic_long_add(x, &mi->vmevents[idx]); - x = 0; - } - __this_cpu_write(memcg->vmstats_percpu->events[idx], x); + memcg_stats_lock(); + __this_cpu_add(memcg->vmstats_percpu->events[index], count); + memcg_rstat_updated(memcg, count); + memcg_stats_unlock(); } static unsigned long memcg_events(struct mem_cgroup *memcg, int event) { - return atomic_long_read(&memcg->vmevents[event]); + int index = memcg_events_index(event); + + if (index < 0) + return 0; + return READ_ONCE(memcg->vmstats->events[index]); } static unsigned long memcg_events_local(struct mem_cgroup *memcg, int event) { - long x = 0; - int cpu; + int index = memcg_events_index(event); - for_each_possible_cpu(cpu) - x += per_cpu(memcg->vmstats_local->events[event], cpu); - return x; + if (index < 0) + return 0; + + return READ_ONCE(memcg->vmstats->events_local[index]); } static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, - struct page *page, int nr_pages) { /* pagein of a big page is an event. So, ignore page size */ @@ -977,8 +1024,11 @@ static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, * Check events in order. * */ -static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) +static void memcg_check_events(struct mem_cgroup *memcg, int nid) { + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + return; + /* threshold event is triggered in finer grain than soft limit */ if (unlikely(mem_cgroup_event_ratelimit(memcg, MEM_CGROUP_TARGET_THRESH))) { @@ -988,7 +1038,7 @@ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) MEM_CGROUP_TARGET_SOFTLIMIT); mem_cgroup_threshold(memcg); if (unlikely(do_softlimit)) - mem_cgroup_update_tree(memcg, page); + mem_cgroup_update_tree(memcg, nid); } } @@ -1006,13 +1056,24 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) } EXPORT_SYMBOL(mem_cgroup_from_task); +static __always_inline struct mem_cgroup *active_memcg(void) +{ + if (!in_task()) + return this_cpu_read(int_active_memcg); + else + return current->active_memcg; +} + /** * get_mem_cgroup_from_mm: Obtain a reference on given mm_struct's memcg. * @mm: mm from which memcg should be extracted. It can be NULL. * - * Obtain a reference on mm->memcg and returns it if successful. Otherwise - * root_mem_cgroup is returned. However if mem_cgroup is disabled, NULL is - * returned. + * Obtain a reference on mm->memcg and returns it if successful. If mm + * is NULL, then the memcg is chosen as follows: + * 1) The active memcg, if set. + * 2) current->mm->memcg, if available + * 3) root memcg + * If mem_cgroup is disabled, NULL is returned. */ struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) { @@ -1021,20 +1082,32 @@ struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) if (mem_cgroup_disabled()) return NULL; + /* + * Page cache insertions can happen without an + * actual mm context, e.g. during disk probing + * on boot, loopback IO, acct() writes etc. + * + * No need to css_get on root memcg as the reference + * counting is disabled on the root level in the + * cgroup core. See CSS_NO_REF. + */ + if (unlikely(!mm)) { + memcg = active_memcg(); + if (unlikely(memcg)) { + /* remote memcg must hold a ref */ + css_get(&memcg->css); + return memcg; + } + mm = current->mm; + if (unlikely(!mm)) + return root_mem_cgroup; + } + rcu_read_lock(); do { - /* - * 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 = mem_cgroup_from_task(rcu_dereference(mm->owner)); + if (unlikely(!memcg)) memcg = root_mem_cgroup; - else { - memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); - if (unlikely(!memcg)) - memcg = root_mem_cgroup; - } } while (!css_tryget(&memcg->css)); rcu_read_unlock(); return memcg; @@ -1042,81 +1115,26 @@ struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) EXPORT_SYMBOL(get_mem_cgroup_from_mm); /** - * get_mem_cgroup_from_page: Obtain a reference on given page's memcg. - * @page: page from which memcg should be extracted. - * - * Obtain a reference on page->memcg and returns it if successful. Otherwise - * root_mem_cgroup is returned. + * get_mem_cgroup_from_current - Obtain a reference on current task's memcg. */ -struct mem_cgroup *get_mem_cgroup_from_page(struct page *page) +struct mem_cgroup *get_mem_cgroup_from_current(void) { - struct mem_cgroup *memcg = page->mem_cgroup; + struct mem_cgroup *memcg; if (mem_cgroup_disabled()) return NULL; +again: rcu_read_lock(); - /* Page should not get uncharged and freed memcg under us. */ - if (!memcg || WARN_ON_ONCE(!css_tryget(&memcg->css))) - memcg = root_mem_cgroup; - rcu_read_unlock(); - return memcg; -} -EXPORT_SYMBOL(get_mem_cgroup_from_page); - -static __always_inline struct mem_cgroup *active_memcg(void) -{ - if (in_interrupt()) - return this_cpu_read(int_active_memcg); - else - return current->active_memcg; -} - -static __always_inline struct mem_cgroup *get_active_memcg(void) -{ - struct mem_cgroup *memcg; - - rcu_read_lock(); - memcg = active_memcg(); - if (memcg) { - /* current->active_memcg must hold a ref. */ - if (WARN_ON_ONCE(!css_tryget(&memcg->css))) - memcg = root_mem_cgroup; - else - memcg = current->active_memcg; + memcg = mem_cgroup_from_task(current); + if (!css_tryget(&memcg->css)) { + rcu_read_unlock(); + goto again; } rcu_read_unlock(); - return memcg; } -static __always_inline bool memcg_kmem_bypass(void) -{ - /* Allow remote memcg charging from any context. */ - if (unlikely(active_memcg())) - return false; - - /* Memcg to charge can't be determined. */ - if (in_interrupt() || !current->mm || (current->flags & PF_KTHREAD)) - return true; - - return false; -} - -/** - * If active memcg is set, do not fallback to current->mm->memcg. - */ -static __always_inline struct mem_cgroup *get_mem_cgroup_from_current(void) -{ - if (memcg_kmem_bypass()) - return NULL; - - if (unlikely(active_memcg())) - return get_active_memcg(); - - return get_mem_cgroup_from_mm(current->mm); -} - /** * mem_cgroup_iter - iterate over memory cgroup hierarchy * @root: hierarchy root @@ -1149,24 +1167,21 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, if (!root) root = root_mem_cgroup; - if (prev && !reclaim) - pos = prev; - - if (!root->use_hierarchy && root != root_mem_cgroup) { - if (prev) - goto out; - return root; - } - rcu_read_lock(); if (reclaim) { struct mem_cgroup_per_node *mz; - mz = mem_cgroup_nodeinfo(root, reclaim->pgdat->node_id); + mz = root->nodeinfo[reclaim->pgdat->node_id]; iter = &mz->iter; - if (prev && reclaim->generation != iter->generation) + /* + * On start, join the current reclaim iteration cycle. + * Exit when a concurrent walker completes it. + */ + if (!prev) + reclaim->generation = iter->generation; + else if (reclaim->generation != iter->generation) goto out_unlock; while (1) { @@ -1183,6 +1198,8 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, */ (void)cmpxchg(&iter->position, pos, NULL); } + } else if (prev) { + pos = prev; } if (pos) @@ -1207,15 +1224,10 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, * is provided by the caller, so we know it's alive * and kicking, and don't take an extra reference. */ - memcg = mem_cgroup_from_css(css); - - if (css == &root->css) - break; - - if (css_tryget(css)) + if (css == &root->css || css_tryget(css)) { + memcg = mem_cgroup_from_css(css); break; - - memcg = NULL; + } } if (reclaim) { @@ -1231,13 +1243,10 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, if (!memcg) iter->generation++; - else if (!prev) - reclaim->generation = iter->generation; } out_unlock: rcu_read_unlock(); -out: if (prev && prev != root) css_put(&prev->css); @@ -1266,7 +1275,7 @@ static void __invalidate_reclaim_iterators(struct mem_cgroup *from, int nid; for_each_node(nid) { - mz = mem_cgroup_nodeinfo(from, nid); + mz = from->nodeinfo[nid]; iter = &mz->iter; cmpxchg(&iter->position, dead_memcg, NULL); } @@ -1283,12 +1292,12 @@ static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg) } while ((memcg = parent_mem_cgroup(memcg))); /* - * When cgruop1 non-hierarchy mode is used, + * When cgroup1 non-hierarchy mode is used, * parent_mem_cgroup() does not walk all the way up to the * cgroup root (root_mem_cgroup). So we have to handle * dead_memcg from cgroup root separately. */ - if (last != root_mem_cgroup) + if (!mem_cgroup_is_root(last)) __invalidate_reclaim_iterators(root_mem_cgroup, dead_memcg); } @@ -1301,18 +1310,18 @@ static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg) * * This function iterates over tasks attached to @memcg or to any of its * descendants and calls @fn for each task. If @fn returns a non-zero - * value, the function breaks the iteration loop and returns the value. - * Otherwise, it will iterate over all tasks and return 0. + * value, the function breaks the iteration loop. Otherwise, it will iterate + * over all tasks and return 0. * * This function must not be called for the root memory cgroup. */ -int mem_cgroup_scan_tasks(struct mem_cgroup *memcg, - int (*fn)(struct task_struct *, void *), void *arg) +void mem_cgroup_scan_tasks(struct mem_cgroup *memcg, + int (*fn)(struct task_struct *, void *), void *arg) { struct mem_cgroup *iter; int ret = 0; - BUG_ON(memcg == root_mem_cgroup); + BUG_ON(mem_cgroup_is_root(memcg)); for_each_mem_cgroup_tree(iter, memcg) { struct css_task_iter it; @@ -1327,46 +1336,92 @@ int mem_cgroup_scan_tasks(struct mem_cgroup *memcg, break; } } - return ret; } +#ifdef CONFIG_DEBUG_VM +void lruvec_memcg_debug(struct lruvec *lruvec, struct folio *folio) +{ + struct mem_cgroup *memcg; + + if (mem_cgroup_disabled()) + return; + + memcg = folio_memcg(folio); + + if (!memcg) + VM_BUG_ON_FOLIO(!mem_cgroup_is_root(lruvec_memcg(lruvec)), folio); + else + VM_BUG_ON_FOLIO(lruvec_memcg(lruvec) != memcg, folio); +} +#endif + /** - * mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page - * @page: the page - * @pgdat: pgdat of the page + * folio_lruvec_lock - Lock the lruvec for a folio. + * @folio: Pointer to the folio. + * + * These functions are safe to use under any of the following conditions: + * - folio locked + * - folio_test_lru false + * - folio_memcg_lock() + * - folio frozen (refcount of 0) * - * This function relies on page->mem_cgroup being stable - see the - * access rules in commit_charge(). + * Return: The lruvec this folio is on with its lock held. */ -struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgdat) +struct lruvec *folio_lruvec_lock(struct folio *folio) { - struct mem_cgroup_per_node *mz; - struct mem_cgroup *memcg; - struct lruvec *lruvec; + struct lruvec *lruvec = folio_lruvec(folio); - if (mem_cgroup_disabled()) { - lruvec = &pgdat->__lruvec; - goto out; - } + spin_lock(&lruvec->lru_lock); + lruvec_memcg_debug(lruvec, folio); - memcg = page->mem_cgroup; - /* - * Swapcache readahead pages are added to the LRU - and - * possibly migrated - before they are charged. - */ - if (!memcg) - memcg = root_mem_cgroup; + return lruvec; +} + +/** + * folio_lruvec_lock_irq - Lock the lruvec for a folio. + * @folio: Pointer to the folio. + * + * These functions are safe to use under any of the following conditions: + * - folio locked + * - folio_test_lru false + * - folio_memcg_lock() + * - folio frozen (refcount of 0) + * + * Return: The lruvec this folio is on with its lock held and interrupts + * disabled. + */ +struct lruvec *folio_lruvec_lock_irq(struct folio *folio) +{ + struct lruvec *lruvec = folio_lruvec(folio); + + spin_lock_irq(&lruvec->lru_lock); + lruvec_memcg_debug(lruvec, folio); + + return lruvec; +} + +/** + * folio_lruvec_lock_irqsave - Lock the lruvec for a folio. + * @folio: Pointer to the folio. + * @flags: Pointer to irqsave flags. + * + * These functions are safe to use under any of the following conditions: + * - folio locked + * - folio_test_lru false + * - folio_memcg_lock() + * - folio frozen (refcount of 0) + * + * Return: The lruvec this folio is on with its lock held and interrupts + * disabled. + */ +struct lruvec *folio_lruvec_lock_irqsave(struct folio *folio, + unsigned long *flags) +{ + struct lruvec *lruvec = folio_lruvec(folio); + + spin_lock_irqsave(&lruvec->lru_lock, *flags); + lruvec_memcg_debug(lruvec, folio); - mz = mem_cgroup_page_nodeinfo(memcg, page); - lruvec = &mz->lruvec; -out: - /* - * Since a node can be onlined after the mem_cgroup was created, - * we have to be prepared to initialize lruvec->zone here; - * and if offlined then reonlined, we need to reinitialize it. - */ - if (unlikely(lruvec->pgdat != pgdat)) - lruvec->pgdat = pgdat; return lruvec; } @@ -1378,8 +1433,7 @@ out: * @nr_pages: positive when adding or negative when removing * * This function must be called under lru_lock, just before a page is added - * to or just after a page is removed from an lru list (that ordering being - * so as to allow it to check that lru_size 0 is consistent with list_empty). + * to or just after a page is removed from an lru list. */ void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru, int zid, int nr_pages) @@ -1486,76 +1540,107 @@ static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg) struct memory_stat { const char *name; - unsigned int ratio; unsigned int idx; }; -static struct memory_stat memory_stats[] = { - { "anon", PAGE_SIZE, NR_ANON_MAPPED }, - { "file", PAGE_SIZE, NR_FILE_PAGES }, - { "kernel_stack", 1024, NR_KERNEL_STACK_KB }, - { "percpu", 1, MEMCG_PERCPU_B }, - { "sock", PAGE_SIZE, MEMCG_SOCK }, - { "shmem", PAGE_SIZE, NR_SHMEM }, - { "file_mapped", PAGE_SIZE, NR_FILE_MAPPED }, - { "file_dirty", PAGE_SIZE, NR_FILE_DIRTY }, - { "file_writeback", PAGE_SIZE, NR_WRITEBACK }, +static const struct memory_stat memory_stats[] = { + { "anon", NR_ANON_MAPPED }, + { "file", NR_FILE_PAGES }, + { "kernel", MEMCG_KMEM }, + { "kernel_stack", NR_KERNEL_STACK_KB }, + { "pagetables", NR_PAGETABLE }, + { "sec_pagetables", NR_SECONDARY_PAGETABLE }, + { "percpu", MEMCG_PERCPU_B }, + { "sock", MEMCG_SOCK }, + { "vmalloc", MEMCG_VMALLOC }, + { "shmem", NR_SHMEM }, +#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP) + { "zswap", MEMCG_ZSWAP_B }, + { "zswapped", MEMCG_ZSWAPPED }, +#endif + { "file_mapped", NR_FILE_MAPPED }, + { "file_dirty", NR_FILE_DIRTY }, + { "file_writeback", NR_WRITEBACK }, +#ifdef CONFIG_SWAP + { "swapcached", NR_SWAPCACHE }, +#endif #ifdef CONFIG_TRANSPARENT_HUGEPAGE - /* - * The ratio will be initialized in memory_stats_init(). Because - * on some architectures, the macro of HPAGE_PMD_SIZE is not - * constant(e.g. powerpc). - */ - { "anon_thp", 0, NR_ANON_THPS }, + { "anon_thp", NR_ANON_THPS }, + { "file_thp", NR_FILE_THPS }, + { "shmem_thp", NR_SHMEM_THPS }, #endif - { "inactive_anon", PAGE_SIZE, NR_INACTIVE_ANON }, - { "active_anon", PAGE_SIZE, NR_ACTIVE_ANON }, - { "inactive_file", PAGE_SIZE, NR_INACTIVE_FILE }, - { "active_file", PAGE_SIZE, NR_ACTIVE_FILE }, - { "unevictable", PAGE_SIZE, NR_UNEVICTABLE }, - - /* - * Note: The slab_reclaimable and slab_unreclaimable must be - * together and slab_reclaimable must be in front. - */ - { "slab_reclaimable", 1, NR_SLAB_RECLAIMABLE_B }, - { "slab_unreclaimable", 1, NR_SLAB_UNRECLAIMABLE_B }, + { "inactive_anon", NR_INACTIVE_ANON }, + { "active_anon", NR_ACTIVE_ANON }, + { "inactive_file", NR_INACTIVE_FILE }, + { "active_file", NR_ACTIVE_FILE }, + { "unevictable", NR_UNEVICTABLE }, + { "slab_reclaimable", NR_SLAB_RECLAIMABLE_B }, + { "slab_unreclaimable", NR_SLAB_UNRECLAIMABLE_B }, /* The memory events */ - { "workingset_refault_anon", 1, WORKINGSET_REFAULT_ANON }, - { "workingset_refault_file", 1, WORKINGSET_REFAULT_FILE }, - { "workingset_activate_anon", 1, WORKINGSET_ACTIVATE_ANON }, - { "workingset_activate_file", 1, WORKINGSET_ACTIVATE_FILE }, - { "workingset_restore_anon", 1, WORKINGSET_RESTORE_ANON }, - { "workingset_restore_file", 1, WORKINGSET_RESTORE_FILE }, - { "workingset_nodereclaim", 1, WORKINGSET_NODERECLAIM }, + { "workingset_refault_anon", WORKINGSET_REFAULT_ANON }, + { "workingset_refault_file", WORKINGSET_REFAULT_FILE }, + { "workingset_activate_anon", WORKINGSET_ACTIVATE_ANON }, + { "workingset_activate_file", WORKINGSET_ACTIVATE_FILE }, + { "workingset_restore_anon", WORKINGSET_RESTORE_ANON }, + { "workingset_restore_file", WORKINGSET_RESTORE_FILE }, + { "workingset_nodereclaim", WORKINGSET_NODERECLAIM }, }; -static int __init memory_stats_init(void) +/* The actual unit of the state item, not the same as the output unit */ +static int memcg_page_state_unit(int item) { - int i; + switch (item) { + case MEMCG_PERCPU_B: + case MEMCG_ZSWAP_B: + case NR_SLAB_RECLAIMABLE_B: + case NR_SLAB_UNRECLAIMABLE_B: + return 1; + case NR_KERNEL_STACK_KB: + return SZ_1K; + default: + return PAGE_SIZE; + } +} - for (i = 0; i < ARRAY_SIZE(memory_stats); i++) { -#ifdef CONFIG_TRANSPARENT_HUGEPAGE - if (memory_stats[i].idx == NR_ANON_THPS) - memory_stats[i].ratio = HPAGE_PMD_SIZE; -#endif - VM_BUG_ON(!memory_stats[i].ratio); - VM_BUG_ON(memory_stats[i].idx >= MEMCG_NR_STAT); +/* Translate stat items to the correct unit for memory.stat output */ +static int memcg_page_state_output_unit(int item) +{ + /* + * Workingset state is actually in pages, but we export it to userspace + * as a scalar count of events, so special case it here. + */ + switch (item) { + case WORKINGSET_REFAULT_ANON: + case WORKINGSET_REFAULT_FILE: + case WORKINGSET_ACTIVATE_ANON: + case WORKINGSET_ACTIVATE_FILE: + case WORKINGSET_RESTORE_ANON: + case WORKINGSET_RESTORE_FILE: + case WORKINGSET_NODERECLAIM: + return 1; + default: + return memcg_page_state_unit(item); } +} - return 0; +static inline unsigned long memcg_page_state_output(struct mem_cgroup *memcg, + int item) +{ + return memcg_page_state(memcg, item) * + memcg_page_state_output_unit(item); } -pure_initcall(memory_stats_init); -static char *memory_stat_format(struct mem_cgroup *memcg) +static inline unsigned long memcg_page_state_local_output( + struct mem_cgroup *memcg, int item) { - struct seq_buf s; - int i; + return memcg_page_state_local(memcg, item) * + memcg_page_state_output_unit(item); +} - seq_buf_init(&s, kmalloc(PAGE_SIZE, GFP_KERNEL), PAGE_SIZE); - if (!s.buffer) - return NULL; +static void memcg_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) +{ + int i; /* * Provide statistics on the state of the memory subsystem as @@ -1567,58 +1652,56 @@ static char *memory_stat_format(struct mem_cgroup *memcg) * * Current memory state: */ + mem_cgroup_flush_stats(memcg); for (i = 0; i < ARRAY_SIZE(memory_stats); i++) { u64 size; - size = memcg_page_state(memcg, memory_stats[i].idx); - size *= memory_stats[i].ratio; - seq_buf_printf(&s, "%s %llu\n", memory_stats[i].name, size); + size = memcg_page_state_output(memcg, memory_stats[i].idx); + seq_buf_printf(s, "%s %llu\n", memory_stats[i].name, size); if (unlikely(memory_stats[i].idx == NR_SLAB_UNRECLAIMABLE_B)) { - size = memcg_page_state(memcg, NR_SLAB_RECLAIMABLE_B) + - memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE_B); - seq_buf_printf(&s, "slab %llu\n", size); + size += memcg_page_state_output(memcg, + NR_SLAB_RECLAIMABLE_B); + seq_buf_printf(s, "slab %llu\n", size); } } /* Accumulated memory events */ - - seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGFAULT), - memcg_events(memcg, PGFAULT)); - seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGMAJFAULT), - memcg_events(memcg, PGMAJFAULT)); - seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGREFILL), - memcg_events(memcg, PGREFILL)); - seq_buf_printf(&s, "pgscan %lu\n", + seq_buf_printf(s, "pgscan %lu\n", memcg_events(memcg, PGSCAN_KSWAPD) + - memcg_events(memcg, PGSCAN_DIRECT)); - seq_buf_printf(&s, "pgsteal %lu\n", + memcg_events(memcg, PGSCAN_DIRECT) + + memcg_events(memcg, PGSCAN_KHUGEPAGED)); + seq_buf_printf(s, "pgsteal %lu\n", memcg_events(memcg, PGSTEAL_KSWAPD) + - memcg_events(memcg, PGSTEAL_DIRECT)); - seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGACTIVATE), - memcg_events(memcg, PGACTIVATE)); - seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGDEACTIVATE), - memcg_events(memcg, PGDEACTIVATE)); - seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGLAZYFREE), - memcg_events(memcg, PGLAZYFREE)); - seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGLAZYFREED), - memcg_events(memcg, PGLAZYFREED)); + memcg_events(memcg, PGSTEAL_DIRECT) + + memcg_events(memcg, PGSTEAL_KHUGEPAGED)); -#ifdef CONFIG_TRANSPARENT_HUGEPAGE - seq_buf_printf(&s, "%s %lu\n", vm_event_name(THP_FAULT_ALLOC), - memcg_events(memcg, THP_FAULT_ALLOC)); - seq_buf_printf(&s, "%s %lu\n", vm_event_name(THP_COLLAPSE_ALLOC), - memcg_events(memcg, THP_COLLAPSE_ALLOC)); -#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ + for (i = 0; i < ARRAY_SIZE(memcg_vm_event_stat); i++) { + if (memcg_vm_event_stat[i] == PGPGIN || + memcg_vm_event_stat[i] == PGPGOUT) + continue; + + seq_buf_printf(s, "%s %lu\n", + vm_event_name(memcg_vm_event_stat[i]), + memcg_events(memcg, memcg_vm_event_stat[i])); + } /* The above should easily fit into one page */ - WARN_ON_ONCE(seq_buf_has_overflowed(&s)); + WARN_ON_ONCE(seq_buf_has_overflowed(s)); +} - return s.buffer; +static void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s); + +static void memory_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) +{ + if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) + memcg_stat_format(memcg, s); + else + memcg1_stat_format(memcg, s); + WARN_ON_ONCE(seq_buf_has_overflowed(s)); } -#define K(x) ((x) << (PAGE_SHIFT-10)) /** * mem_cgroup_print_oom_context: Print OOM information relevant to * memory controller. @@ -1651,7 +1734,11 @@ void mem_cgroup_print_oom_context(struct mem_cgroup *memcg, struct task_struct * */ void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg) { - char *buf; + /* Use static buffer, for the caller is holding oom_lock. */ + static char buf[PAGE_SIZE]; + struct seq_buf s; + + lockdep_assert_held(&oom_lock); pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n", K((u64)page_counter_read(&memcg->memory)), @@ -1672,11 +1759,9 @@ void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg) pr_info("Memory cgroup stats for "); pr_cont_cgroup_path(memcg->css.cgroup); pr_cont(":"); - buf = memory_stat_format(memcg); - if (!buf) - return; - pr_info("%s", buf); - kfree(buf); + seq_buf_init(&s, buf, sizeof(buf)); + memory_stat_format(memcg, &s); + seq_buf_do_printk(&s, KERN_INFO); } /* @@ -1686,17 +1771,17 @@ unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg) { unsigned long max = READ_ONCE(memcg->memory.max); - if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) { - if (mem_cgroup_swappiness(memcg)) - max += min(READ_ONCE(memcg->swap.max), - (unsigned long)total_swap_pages); - } else { /* v1 */ + if (do_memsw_account()) { if (mem_cgroup_swappiness(memcg)) { /* Calculate swap excess capacity from memsw limit */ unsigned long swap = READ_ONCE(memcg->memsw.max) - max; max += min(swap, (unsigned long)total_swap_pages); } + } else { + if (mem_cgroup_swappiness(memcg)) + max += min(READ_ONCE(memcg->swap.max), + (unsigned long)total_swap_pages); } return max; } @@ -1728,7 +1813,7 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, * A few threads which were not waiting at mutex_lock_killable() can * fail to bail out. Therefore, check again after holding oom_lock. */ - ret = should_force_charge() || out_of_memory(&oc); + ret = task_is_dying() || out_of_memory(&oc); unlock: mutex_unlock(&oom_lock); @@ -1862,7 +1947,7 @@ static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg) struct mem_cgroup *iter; /* - * Be careful about under_oom underflows becase a child memcg + * Be careful about under_oom underflows because a child memcg * could have been added after mem_cgroup_mark_under_oom. */ spin_lock(&memcg_oom_lock); @@ -1909,20 +1994,16 @@ static void memcg_oom_recover(struct mem_cgroup *memcg) __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg); } -enum oom_status { - OOM_SUCCESS, - OOM_FAILED, - OOM_ASYNC, - OOM_SKIPPED -}; - -static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order) +/* + * Returns true if successfully killed one or more processes. Though in some + * corner cases it can return true even without killing any process. + */ +static bool mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order) { - enum oom_status ret; - bool locked; + bool locked, ret; if (order > PAGE_ALLOC_COSTLY_ORDER) - return OOM_SKIPPED; + return false; memcg_memory_event(memcg, MEMCG_OOM); @@ -1944,15 +2025,14 @@ static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int * Please note that mem_cgroup_out_of_memory might fail to find a * victim and then we have to bail out from the charge path. */ - if (memcg->oom_kill_disable) { - if (!current->in_user_fault) - return OOM_SKIPPED; - css_get(&memcg->css); - current->memcg_in_oom = memcg; - current->memcg_oom_gfp_mask = mask; - current->memcg_oom_order = order; - - return OOM_ASYNC; + if (READ_ONCE(memcg->oom_kill_disable)) { + if (current->in_user_fault) { + css_get(&memcg->css); + current->memcg_in_oom = memcg; + current->memcg_oom_gfp_mask = mask; + current->memcg_oom_order = order; + } + return false; } mem_cgroup_mark_under_oom(memcg); @@ -1963,10 +2043,7 @@ static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int mem_cgroup_oom_notify(memcg); mem_cgroup_unmark_under_oom(memcg); - if (mem_cgroup_out_of_memory(memcg, mask, order)) - ret = OOM_SUCCESS; - else - ret = OOM_FAILED; + ret = mem_cgroup_out_of_memory(memcg, mask, order); if (locked) mem_cgroup_oom_unlock(memcg); @@ -2018,26 +2095,12 @@ bool mem_cgroup_oom_synchronize(bool handle) if (locked) mem_cgroup_oom_notify(memcg); - 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, current->memcg_oom_gfp_mask, - current->memcg_oom_order); - } else { - schedule(); - mem_cgroup_unmark_under_oom(memcg); - finish_wait(&memcg_oom_waitq, &owait.wait); - } + schedule(); + mem_cgroup_unmark_under_oom(memcg); + finish_wait(&memcg_oom_waitq, &owait.wait); - if (locked) { + 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_in_oom = NULL; css_put(&memcg->css); @@ -2069,7 +2132,7 @@ struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim, rcu_read_lock(); memcg = mem_cgroup_from_task(victim); - if (memcg == root_mem_cgroup) + if (mem_cgroup_is_root(memcg)) goto out; /* @@ -2086,7 +2149,7 @@ struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim, * highest-level memory cgroup with oom.group set. */ for (; memcg; memcg = parent_mem_cgroup(memcg)) { - if (memcg->oom_group) + if (READ_ONCE(memcg->oom_group)) oom_group = memcg; if (memcg == oom_domain) @@ -2109,19 +2172,17 @@ void mem_cgroup_print_oom_group(struct mem_cgroup *memcg) } /** - * lock_page_memcg - lock a page->mem_cgroup binding - * @page: the page + * folio_memcg_lock - Bind a folio to its memcg. + * @folio: The folio. * - * This function protects unlocked LRU pages from being moved to + * This function prevents unlocked LRU folios from being moved to * another cgroup. * - * It ensures lifetime of the returned memcg. Caller is responsible - * for the lifetime of the page; __unlock_page_memcg() is available - * when @page might get freed inside the locked section. + * It ensures lifetime of the bound memcg. The caller is responsible + * for the lifetime of the folio. */ -struct mem_cgroup *lock_page_memcg(struct page *page) +void folio_memcg_lock(struct folio *folio) { - struct page *head = compound_head(page); /* rmap on tail pages */ struct mem_cgroup *memcg; unsigned long flags; @@ -2129,50 +2190,42 @@ struct mem_cgroup *lock_page_memcg(struct page *page) * The RCU lock is held throughout the transaction. The fast * path can get away without acquiring the memcg->move_lock * because page moving starts with an RCU grace period. - * - * The RCU lock also protects the memcg from being freed when - * the page state that is going to change is the only thing - * preventing the page itself from being freed. E.g. writeback - * doesn't hold a page reference and relies on PG_writeback to - * keep off truncation, migration and so forth. */ rcu_read_lock(); if (mem_cgroup_disabled()) - return NULL; + return; again: - memcg = head->mem_cgroup; + memcg = folio_memcg(folio); if (unlikely(!memcg)) - return NULL; + return; + +#ifdef CONFIG_PROVE_LOCKING + local_irq_save(flags); + might_lock(&memcg->move_lock); + local_irq_restore(flags); +#endif if (atomic_read(&memcg->moving_account) <= 0) - return memcg; + return; spin_lock_irqsave(&memcg->move_lock, flags); - if (memcg != head->mem_cgroup) { + if (memcg != folio_memcg(folio)) { spin_unlock_irqrestore(&memcg->move_lock, flags); goto again; } /* - * When charge migration first begins, we can have locked and - * unlocked page stat updates happening concurrently. Track - * the task who has the lock for unlock_page_memcg(). + * When charge migration first begins, we can have multiple + * critical sections holding the fast-path RCU lock and one + * holding the slowpath move_lock. Track the task who has the + * move_lock for folio_memcg_unlock(). */ memcg->move_lock_task = current; memcg->move_lock_flags = flags; - - return memcg; } -EXPORT_SYMBOL(lock_page_memcg); -/** - * __unlock_page_memcg - unlock and unpin a memcg - * @memcg: the memcg - * - * Unlock and unpin a memcg returned by lock_page_memcg(). - */ -void __unlock_page_memcg(struct mem_cgroup *memcg) +static void __folio_memcg_unlock(struct mem_cgroup *memcg) { if (memcg && memcg->move_lock_task == current) { unsigned long flags = memcg->move_lock_flags; @@ -2187,47 +2240,59 @@ void __unlock_page_memcg(struct mem_cgroup *memcg) } /** - * unlock_page_memcg - unlock a page->mem_cgroup binding - * @page: the page + * folio_memcg_unlock - Release the binding between a folio and its memcg. + * @folio: The folio. + * + * This releases the binding created by folio_memcg_lock(). This does + * not change the accounting of this folio to its memcg, but it does + * permit others to change it. */ -void unlock_page_memcg(struct page *page) +void folio_memcg_unlock(struct folio *folio) { - struct page *head = compound_head(page); - - __unlock_page_memcg(head->mem_cgroup); + __folio_memcg_unlock(folio_memcg(folio)); } -EXPORT_SYMBOL(unlock_page_memcg); struct memcg_stock_pcp { + local_lock_t stock_lock; struct mem_cgroup *cached; /* this never be root cgroup */ unsigned int nr_pages; #ifdef CONFIG_MEMCG_KMEM struct obj_cgroup *cached_objcg; + struct pglist_data *cached_pgdat; unsigned int nr_bytes; + int nr_slab_reclaimable_b; + int nr_slab_unreclaimable_b; #endif struct work_struct work; unsigned long flags; #define FLUSHING_CACHED_CHARGE 0 }; -static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock); +static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock) = { + .stock_lock = INIT_LOCAL_LOCK(stock_lock), +}; static DEFINE_MUTEX(percpu_charge_mutex); #ifdef CONFIG_MEMCG_KMEM -static void drain_obj_stock(struct memcg_stock_pcp *stock); +static struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock); static bool obj_stock_flush_required(struct memcg_stock_pcp *stock, struct mem_cgroup *root_memcg); +static void memcg_account_kmem(struct mem_cgroup *memcg, int nr_pages); #else -static inline void drain_obj_stock(struct memcg_stock_pcp *stock) +static inline struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock) { + return NULL; } static bool obj_stock_flush_required(struct memcg_stock_pcp *stock, struct mem_cgroup *root_memcg) { return false; } +static void memcg_account_kmem(struct mem_cgroup *memcg, int nr_pages) +{ +} #endif /** @@ -2250,15 +2315,15 @@ static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages) if (nr_pages > MEMCG_CHARGE_BATCH) return ret; - local_irq_save(flags); + local_lock_irqsave(&memcg_stock.stock_lock, flags); stock = this_cpu_ptr(&memcg_stock); - if (memcg == stock->cached && stock->nr_pages >= nr_pages) { + if (memcg == READ_ONCE(stock->cached) && stock->nr_pages >= nr_pages) { stock->nr_pages -= nr_pages; ret = true; } - local_irq_restore(flags); + local_unlock_irqrestore(&memcg_stock.stock_lock, flags); return ret; } @@ -2268,7 +2333,7 @@ static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages) */ static void drain_stock(struct memcg_stock_pcp *stock) { - struct mem_cgroup *old = stock->cached; + struct mem_cgroup *old = READ_ONCE(stock->cached); if (!old) return; @@ -2281,51 +2346,59 @@ static void drain_stock(struct memcg_stock_pcp *stock) } css_put(&old->css); - stock->cached = NULL; + WRITE_ONCE(stock->cached, NULL); } static void drain_local_stock(struct work_struct *dummy) { struct memcg_stock_pcp *stock; + struct obj_cgroup *old = NULL; unsigned long flags; /* - * The only protection from memory hotplug vs. drain_stock races is - * that we always operate on local CPU stock here with IRQ disabled + * The only protection from cpu hotplug (memcg_hotplug_cpu_dead) vs. + * drain_stock races is that we always operate on local CPU stock + * here with IRQ disabled */ - local_irq_save(flags); + local_lock_irqsave(&memcg_stock.stock_lock, flags); stock = this_cpu_ptr(&memcg_stock); - drain_obj_stock(stock); + old = drain_obj_stock(stock); drain_stock(stock); clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); - local_irq_restore(flags); + local_unlock_irqrestore(&memcg_stock.stock_lock, flags); + if (old) + obj_cgroup_put(old); } /* * Cache charges(val) to local per_cpu area. * This will be consumed by consume_stock() function, later. */ -static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages) +static void __refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages) { struct memcg_stock_pcp *stock; - unsigned long flags; - - local_irq_save(flags); stock = this_cpu_ptr(&memcg_stock); - if (stock->cached != memcg) { /* reset if necessary */ + if (READ_ONCE(stock->cached) != memcg) { /* reset if necessary */ drain_stock(stock); css_get(&memcg->css); - stock->cached = memcg; + WRITE_ONCE(stock->cached, memcg); } stock->nr_pages += nr_pages; if (stock->nr_pages > MEMCG_CHARGE_BATCH) drain_stock(stock); +} - local_irq_restore(flags); +static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages) +{ + unsigned long flags; + + local_lock_irqsave(&memcg_stock.stock_lock, flags); + __refill_stock(memcg, nr_pages); + local_unlock_irqrestore(&memcg_stock.stock_lock, flags); } /* @@ -2345,18 +2418,19 @@ static void drain_all_stock(struct mem_cgroup *root_memcg) * as well as workers from this path always operate on the local * per-cpu data. CPU up doesn't touch memcg_stock at all. */ - curcpu = get_cpu(); + migrate_disable(); + curcpu = smp_processor_id(); for_each_online_cpu(cpu) { struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); struct mem_cgroup *memcg; bool flush = false; rcu_read_lock(); - memcg = stock->cached; + memcg = READ_ONCE(stock->cached); if (memcg && stock->nr_pages && mem_cgroup_is_descendant(memcg, root_memcg)) flush = true; - if (obj_stock_flush_required(stock, root_memcg)) + else if (obj_stock_flush_required(stock, root_memcg)) flush = true; rcu_read_unlock(); @@ -2364,59 +2438,21 @@ static void drain_all_stock(struct mem_cgroup *root_memcg) !test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) { if (cpu == curcpu) drain_local_stock(&stock->work); - else + else if (!cpu_is_isolated(cpu)) schedule_work_on(cpu, &stock->work); } } - put_cpu(); + migrate_enable(); mutex_unlock(&percpu_charge_mutex); } static int memcg_hotplug_cpu_dead(unsigned int cpu) { struct memcg_stock_pcp *stock; - struct mem_cgroup *memcg, *mi; stock = &per_cpu(memcg_stock, cpu); drain_stock(stock); - for_each_mem_cgroup(memcg) { - int i; - - for (i = 0; i < MEMCG_NR_STAT; i++) { - int nid; - long x; - - x = this_cpu_xchg(memcg->vmstats_percpu->stat[i], 0); - if (x) - for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) - atomic_long_add(x, &memcg->vmstats[i]); - - if (i >= NR_VM_NODE_STAT_ITEMS) - continue; - - for_each_node(nid) { - struct mem_cgroup_per_node *pn; - - pn = mem_cgroup_nodeinfo(memcg, nid); - x = this_cpu_xchg(pn->lruvec_stat_cpu->count[i], 0); - if (x) - do { - atomic_long_add(x, &pn->lruvec_stat[i]); - } while ((pn = parent_nodeinfo(pn, nid))); - } - } - - for (i = 0; i < NR_VM_EVENT_ITEMS; i++) { - long x; - - x = this_cpu_xchg(memcg->vmstats_percpu->events[i], 0); - if (x) - for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) - atomic_long_add(x, &memcg->vmevents[i]); - } - } - return 0; } @@ -2437,7 +2473,8 @@ static unsigned long reclaim_high(struct mem_cgroup *memcg, psi_memstall_enter(&pflags); nr_reclaimed += try_to_free_mem_cgroup_pages(memcg, nr_pages, - gfp_mask, true); + gfp_mask, + MEMCG_RECLAIM_MAY_SWAP); psi_memstall_leave(&pflags); } while ((memcg = parent_mem_cgroup(memcg)) && !mem_cgroup_is_root(memcg)); @@ -2591,10 +2628,11 @@ static unsigned long calculate_high_delay(struct mem_cgroup *memcg, } /* - * Scheduled by try_charge() to be executed from the userland return path - * and reclaims memory over the high limit. + * Reclaims memory over the high limit. Called directly from + * try_charge() (context permitting), as well as from the userland + * return path where reclaim is always able to block. */ -void mem_cgroup_handle_over_high(void) +void mem_cgroup_handle_over_high(gfp_t gfp_mask) { unsigned long penalty_jiffies; unsigned long pflags; @@ -2612,6 +2650,17 @@ void mem_cgroup_handle_over_high(void) retry_reclaim: /* + * Bail if the task is already exiting. Unlike memory.max, + * memory.high enforcement isn't as strict, and there is no + * OOM killer involved, which means the excess could already + * be much bigger (and still growing) than it could for + * memory.max; the dying task could get stuck in fruitless + * reclaim for a long time, which isn't desirable. + */ + if (task_is_dying()) + goto out; + + /* * The allocating task should reclaim at least the batch size, but for * subsequent retries we only want to do what's necessary to prevent oom * or breaching resource isolation. @@ -2622,7 +2671,7 @@ retry_reclaim: */ nr_reclaimed = reclaim_high(memcg, in_retry ? SWAP_CLUSTER_MAX : nr_pages, - GFP_KERNEL); + gfp_mask); /* * memory.high is breached and reclaim is unable to keep up. Throttle @@ -2661,6 +2710,9 @@ retry_reclaim: } /* + * Reclaim didn't manage to push usage below the limit, slow + * this allocating task down. + * * If we exit early, we're guaranteed to die (since * schedule_timeout_killable sets TASK_KILLABLE). This means we don't * need to account for any ill-begotten jiffies to pay them off later. @@ -2673,21 +2725,20 @@ out: css_put(&memcg->css); } -static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, - unsigned int nr_pages) +static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask, + unsigned int nr_pages) { unsigned int batch = max(MEMCG_CHARGE_BATCH, nr_pages); int nr_retries = MAX_RECLAIM_RETRIES; struct mem_cgroup *mem_over_limit; struct page_counter *counter; - enum oom_status oom_status; unsigned long nr_reclaimed; - bool may_swap = true; + bool passed_oom = false; + unsigned int reclaim_options = MEMCG_RECLAIM_MAY_SWAP; bool drained = false; + bool raised_max_event = false; unsigned long pflags; - if (mem_cgroup_is_root(memcg)) - return 0; retry: if (consume_stock(memcg, nr_pages)) return 0; @@ -2701,7 +2752,7 @@ retry: mem_over_limit = mem_cgroup_from_counter(counter, memory); } else { mem_over_limit = mem_cgroup_from_counter(counter, memsw); - may_swap = false; + reclaim_options &= ~MEMCG_RECLAIM_MAY_SWAP; } if (batch > nr_pages) { @@ -2710,24 +2761,6 @@ retry: } /* - * Memcg doesn't have a dedicated reserve for atomic - * allocations. But like the global atomic pool, we need to - * put the burden of reclaim on regular allocation requests - * and let these go through as privileged allocations. - */ - if (gfp_mask & __GFP_ATOMIC) - goto force; - - /* - * 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(should_force_charge())) - goto force; - - /* * Prevent unbounded recursion when reclaim operations need to * allocate memory. This might exceed the limits temporarily, * but we prefer facilitating memory reclaim and getting back @@ -2743,10 +2776,11 @@ retry: goto nomem; memcg_memory_event(mem_over_limit, MEMCG_MAX); + raised_max_event = true; psi_memstall_enter(&pflags); nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages, - gfp_mask, may_swap); + gfp_mask, reclaim_options); psi_memstall_leave(&pflags); if (mem_cgroup_margin(mem_over_limit) >= nr_pages) @@ -2784,33 +2818,39 @@ retry: if (gfp_mask & __GFP_RETRY_MAYFAIL) goto nomem; - if (gfp_mask & __GFP_NOFAIL) - goto force; - - if (fatal_signal_pending(current)) - goto force; + /* Avoid endless loop for tasks bypassed by the oom killer */ + if (passed_oom && task_is_dying()) + goto nomem; /* * keep retrying as long as the memcg oom killer is able to make * a forward progress or bypass the charge if the oom killer * couldn't make any progress. */ - oom_status = mem_cgroup_oom(mem_over_limit, gfp_mask, - get_order(nr_pages * PAGE_SIZE)); - switch (oom_status) { - case OOM_SUCCESS: + if (mem_cgroup_oom(mem_over_limit, gfp_mask, + get_order(nr_pages * PAGE_SIZE))) { + passed_oom = true; nr_retries = MAX_RECLAIM_RETRIES; goto retry; - case OOM_FAILED: - goto force; - default: - goto nomem; } nomem: - if (!(gfp_mask & __GFP_NOFAIL)) + /* + * Memcg doesn't have a dedicated reserve for atomic + * allocations. But like the global atomic pool, we need to + * put the burden of reclaim on regular allocation requests + * and let these go through as privileged allocations. + */ + if (!(gfp_mask & (__GFP_NOFAIL | __GFP_HIGH))) return -ENOMEM; force: /* + * If the allocation has to be enforced, don't forget to raise + * a MEMCG_MAX event. + */ + if (!raised_max_event) + memcg_memory_event(mem_over_limit, MEMCG_MAX); + + /* * The allocation either can't fail or will lead to more memory * being freed very soon. Allow memory usage go over the limit * temporarily by force charging it. @@ -2843,7 +2883,7 @@ done_restock: READ_ONCE(memcg->swap.high); /* Don't bother a random interrupted task */ - if (in_interrupt()) { + if (!in_task()) { if (mem_high) { schedule_work(&memcg->high_work); break; @@ -2867,11 +2907,35 @@ done_restock: } } while ((memcg = parent_mem_cgroup(memcg))); + /* + * Reclaim is set up above to be called from the userland + * return path. But also attempt synchronous reclaim to avoid + * excessive overrun while the task is still inside the + * kernel. If this is successful, the return path will see it + * when it rechecks the overage and simply bail out. + */ + if (current->memcg_nr_pages_over_high > MEMCG_CHARGE_BATCH && + !(current->flags & PF_MEMALLOC) && + gfpflags_allow_blocking(gfp_mask)) + mem_cgroup_handle_over_high(gfp_mask); return 0; } -#if defined(CONFIG_MEMCG_KMEM) || defined(CONFIG_MMU) -static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages) +static inline int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, + unsigned int nr_pages) +{ + if (mem_cgroup_is_root(memcg)) + return 0; + + return try_charge_memcg(memcg, gfp_mask, nr_pages); +} + +/** + * mem_cgroup_cancel_charge() - cancel an uncommitted try_charge() call. + * @memcg: memcg previously charged. + * @nr_pages: number of pages previously charged. + */ +void mem_cgroup_cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages) { if (mem_cgroup_is_root(memcg)) return; @@ -2880,206 +2944,369 @@ static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages) if (do_memsw_account()) page_counter_uncharge(&memcg->memsw, nr_pages); } -#endif -static void commit_charge(struct page *page, struct mem_cgroup *memcg) +static void commit_charge(struct folio *folio, struct mem_cgroup *memcg) { - VM_BUG_ON_PAGE(page->mem_cgroup, page); + VM_BUG_ON_FOLIO(folio_memcg(folio), folio); /* - * Any of the following ensures page->mem_cgroup stability: + * Any of the following ensures page's memcg stability: * * - the page lock * - LRU isolation - * - lock_page_memcg() + * - folio_memcg_lock() * - exclusive reference + * - mem_cgroup_trylock_pages() */ - page->mem_cgroup = memcg; + folio->memcg_data = (unsigned long)memcg; +} + +/** + * mem_cgroup_commit_charge - commit a previously successful try_charge(). + * @folio: folio to commit the charge to. + * @memcg: memcg previously charged. + */ +void mem_cgroup_commit_charge(struct folio *folio, struct mem_cgroup *memcg) +{ + css_get(&memcg->css); + commit_charge(folio, memcg); + + local_irq_disable(); + mem_cgroup_charge_statistics(memcg, folio_nr_pages(folio)); + memcg_check_events(memcg, folio_nid(folio)); + local_irq_enable(); } #ifdef CONFIG_MEMCG_KMEM -int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s, - gfp_t gfp) +/* + * The allocated objcg pointers array is not accounted directly. + * Moreover, it should not come from DMA buffer and is not readily + * reclaimable. So those GFP bits should be masked off. + */ +#define OBJCGS_CLEAR_MASK (__GFP_DMA | __GFP_RECLAIMABLE | \ + __GFP_ACCOUNT | __GFP_NOFAIL) + +/* + * mod_objcg_mlstate() may be called with irq enabled, so + * mod_memcg_lruvec_state() should be used. + */ +static inline void mod_objcg_mlstate(struct obj_cgroup *objcg, + struct pglist_data *pgdat, + enum node_stat_item idx, int nr) { - unsigned int objects = objs_per_slab_page(s, page); + struct mem_cgroup *memcg; + struct lruvec *lruvec; + + rcu_read_lock(); + memcg = obj_cgroup_memcg(objcg); + lruvec = mem_cgroup_lruvec(memcg, pgdat); + mod_memcg_lruvec_state(lruvec, idx, nr); + rcu_read_unlock(); +} + +int memcg_alloc_slab_cgroups(struct slab *slab, struct kmem_cache *s, + gfp_t gfp, bool new_slab) +{ + unsigned int objects = objs_per_slab(s, slab); + unsigned long memcg_data; void *vec; + gfp &= ~OBJCGS_CLEAR_MASK; vec = kcalloc_node(objects, sizeof(struct obj_cgroup *), gfp, - page_to_nid(page)); + slab_nid(slab)); if (!vec) return -ENOMEM; - if (cmpxchg(&page->obj_cgroups, NULL, - (struct obj_cgroup **) ((unsigned long)vec | 0x1UL))) + memcg_data = (unsigned long) vec | MEMCG_DATA_OBJCGS; + if (new_slab) { + /* + * If the slab is brand new and nobody can yet access its + * memcg_data, no synchronization is required and memcg_data can + * be simply assigned. + */ + slab->memcg_data = memcg_data; + } else if (cmpxchg(&slab->memcg_data, 0, memcg_data)) { + /* + * If the slab is already in use, somebody can allocate and + * assign obj_cgroups in parallel. In this case the existing + * objcg vector should be reused. + */ kfree(vec); - else - kmemleak_not_leak(vec); + return 0; + } + kmemleak_not_leak(vec); return 0; } +static __always_inline +struct mem_cgroup *mem_cgroup_from_obj_folio(struct folio *folio, void *p) +{ + /* + * Slab objects are accounted individually, not per-page. + * Memcg membership data for each individual object is saved in + * slab->memcg_data. + */ + if (folio_test_slab(folio)) { + struct obj_cgroup **objcgs; + struct slab *slab; + unsigned int off; + + slab = folio_slab(folio); + objcgs = slab_objcgs(slab); + if (!objcgs) + return NULL; + + off = obj_to_index(slab->slab_cache, slab, p); + if (objcgs[off]) + return obj_cgroup_memcg(objcgs[off]); + + return NULL; + } + + /* + * folio_memcg_check() is used here, because in theory we can encounter + * a folio where the slab flag has been cleared already, but + * slab->memcg_data has not been freed yet + * folio_memcg_check() will guarantee that a proper memory + * cgroup pointer or NULL will be returned. + */ + return folio_memcg_check(folio); +} + /* * Returns a pointer to the memory cgroup to which the kernel object is charged. * + * A passed kernel object can be a slab object, vmalloc object or a generic + * kernel page, so different mechanisms for getting the memory cgroup pointer + * should be used. + * + * In certain cases (e.g. kernel stacks or large kmallocs with SLUB) the caller + * can not know for sure how the kernel object is implemented. + * mem_cgroup_from_obj() can be safely used in such cases. + * * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(), * cgroup_mutex, etc. */ struct mem_cgroup *mem_cgroup_from_obj(void *p) { - struct page *page; + struct folio *folio; if (mem_cgroup_disabled()) return NULL; - page = virt_to_head_page(p); + if (unlikely(is_vmalloc_addr(p))) + folio = page_folio(vmalloc_to_page(p)); + else + folio = virt_to_folio(p); - /* - * If page->mem_cgroup is set, it's either a simple mem_cgroup pointer - * or a pointer to obj_cgroup vector. In the latter case the lowest - * bit of the pointer is set. - * The page->mem_cgroup pointer can be asynchronously changed - * from NULL to (obj_cgroup_vec | 0x1UL), but can't be changed - * from a valid memcg pointer to objcg vector or back. - */ - if (!page->mem_cgroup) + return mem_cgroup_from_obj_folio(folio, p); +} + +/* + * Returns a pointer to the memory cgroup to which the kernel object is charged. + * Similar to mem_cgroup_from_obj(), but faster and not suitable for objects, + * allocated using vmalloc(). + * + * A passed kernel object must be a slab object or a generic kernel page. + * + * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(), + * cgroup_mutex, etc. + */ +struct mem_cgroup *mem_cgroup_from_slab_obj(void *p) +{ + if (mem_cgroup_disabled()) return NULL; - /* - * Slab objects are accounted individually, not per-page. - * Memcg membership data for each individual object is saved in - * the page->obj_cgroups. - */ - if (page_has_obj_cgroups(page)) { - struct obj_cgroup *objcg; - unsigned int off; + return mem_cgroup_from_obj_folio(virt_to_folio(p), p); +} - off = obj_to_index(page->slab_cache, page, p); - objcg = page_obj_cgroups(page)[off]; - if (objcg) - return obj_cgroup_memcg(objcg); +static struct obj_cgroup *__get_obj_cgroup_from_memcg(struct mem_cgroup *memcg) +{ + struct obj_cgroup *objcg = NULL; - return NULL; + for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) { + objcg = rcu_dereference(memcg->objcg); + if (likely(objcg && obj_cgroup_tryget(objcg))) + break; + objcg = NULL; } - - /* All other pages use page->mem_cgroup */ - return page->mem_cgroup; + return objcg; } -__always_inline struct obj_cgroup *get_obj_cgroup_from_current(void) +static struct obj_cgroup *current_objcg_update(void) { - struct obj_cgroup *objcg = NULL; struct mem_cgroup *memcg; + struct obj_cgroup *old, *objcg = NULL; - if (memcg_kmem_bypass()) - return NULL; + do { + /* Atomically drop the update bit. */ + old = xchg(¤t->objcg, NULL); + if (old) { + old = (struct obj_cgroup *) + ((unsigned long)old & ~CURRENT_OBJCG_UPDATE_FLAG); + if (old) + obj_cgroup_put(old); + + old = NULL; + } - rcu_read_lock(); - if (unlikely(active_memcg())) - memcg = active_memcg(); - else + /* If new objcg is NULL, no reason for the second atomic update. */ + if (!current->mm || (current->flags & PF_KTHREAD)) + return NULL; + + /* + * Release the objcg pointer from the previous iteration, + * if try_cmpxcg() below fails. + */ + if (unlikely(objcg)) { + obj_cgroup_put(objcg); + objcg = NULL; + } + + /* + * Obtain the new objcg pointer. The current task can be + * asynchronously moved to another memcg and the previous + * memcg can be offlined. So let's get the memcg pointer + * and try get a reference to objcg under a rcu read lock. + */ + + rcu_read_lock(); memcg = mem_cgroup_from_task(current); + objcg = __get_obj_cgroup_from_memcg(memcg); + rcu_read_unlock(); - for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) { - objcg = rcu_dereference(memcg->objcg); - if (objcg && obj_cgroup_tryget(objcg)) - break; - } - rcu_read_unlock(); + /* + * Try set up a new objcg pointer atomically. If it + * fails, it means the update flag was set concurrently, so + * the whole procedure should be repeated. + */ + } while (!try_cmpxchg(¤t->objcg, &old, objcg)); return objcg; } -static int memcg_alloc_cache_id(void) +__always_inline struct obj_cgroup *current_obj_cgroup(void) { - int id, size; - int err; + struct mem_cgroup *memcg; + struct obj_cgroup *objcg; - id = ida_simple_get(&memcg_cache_ida, - 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL); - if (id < 0) - return id; + if (in_task()) { + memcg = current->active_memcg; + if (unlikely(memcg)) + goto from_memcg; - if (id < memcg_nr_cache_ids) - return id; + objcg = READ_ONCE(current->objcg); + if (unlikely((unsigned long)objcg & CURRENT_OBJCG_UPDATE_FLAG)) + objcg = current_objcg_update(); + /* + * Objcg reference is kept by the task, so it's safe + * to use the objcg by the current task. + */ + return objcg; + } - /* - * There's no space for the new id in memcg_caches arrays, - * so we have to grow them. - */ - down_write(&memcg_cache_ids_sem); + memcg = this_cpu_read(int_active_memcg); + if (unlikely(memcg)) + goto from_memcg; - size = 2 * (id + 1); - if (size < MEMCG_CACHES_MIN_SIZE) - size = MEMCG_CACHES_MIN_SIZE; - else if (size > MEMCG_CACHES_MAX_SIZE) - size = MEMCG_CACHES_MAX_SIZE; + return NULL; - err = memcg_update_all_list_lrus(size); - if (!err) - memcg_nr_cache_ids = size; +from_memcg: + objcg = NULL; + for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) { + /* + * Memcg pointer is protected by scope (see set_active_memcg()) + * and is pinning the corresponding objcg, so objcg can't go + * away and can be used within the scope without any additional + * protection. + */ + objcg = rcu_dereference_check(memcg->objcg, 1); + if (likely(objcg)) + break; + } - up_write(&memcg_cache_ids_sem); + return objcg; +} - if (err) { - ida_simple_remove(&memcg_cache_ida, id); - return err; +struct obj_cgroup *get_obj_cgroup_from_folio(struct folio *folio) +{ + struct obj_cgroup *objcg; + + if (!memcg_kmem_online()) + return NULL; + + if (folio_memcg_kmem(folio)) { + objcg = __folio_objcg(folio); + obj_cgroup_get(objcg); + } else { + struct mem_cgroup *memcg; + + rcu_read_lock(); + memcg = __folio_memcg(folio); + if (memcg) + objcg = __get_obj_cgroup_from_memcg(memcg); + else + objcg = NULL; + rcu_read_unlock(); } - return id; + return objcg; } -static void memcg_free_cache_id(int id) +static void memcg_account_kmem(struct mem_cgroup *memcg, int nr_pages) { - ida_simple_remove(&memcg_cache_ida, id); + mod_memcg_state(memcg, MEMCG_KMEM, nr_pages); + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) { + if (nr_pages > 0) + page_counter_charge(&memcg->kmem, nr_pages); + else + page_counter_uncharge(&memcg->kmem, -nr_pages); + } } -/** - * __memcg_kmem_charge: charge a number of kernel pages to a memcg - * @memcg: memory cgroup to charge + +/* + * obj_cgroup_uncharge_pages: uncharge a number of kernel pages from a objcg + * @objcg: object cgroup to uncharge + * @nr_pages: number of pages to uncharge + */ +static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg, + unsigned int nr_pages) +{ + struct mem_cgroup *memcg; + + memcg = get_mem_cgroup_from_objcg(objcg); + + memcg_account_kmem(memcg, -nr_pages); + refill_stock(memcg, nr_pages); + + css_put(&memcg->css); +} + +/* + * obj_cgroup_charge_pages: charge a number of kernel pages to a objcg + * @objcg: object cgroup to charge * @gfp: reclaim mode * @nr_pages: number of pages to charge * * Returns 0 on success, an error code on failure. */ -int __memcg_kmem_charge(struct mem_cgroup *memcg, gfp_t gfp, - unsigned int nr_pages) +static int obj_cgroup_charge_pages(struct obj_cgroup *objcg, gfp_t gfp, + unsigned int nr_pages) { - struct page_counter *counter; + struct mem_cgroup *memcg; int ret; - ret = try_charge(memcg, gfp, nr_pages); - if (ret) - return ret; - - if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && - !page_counter_try_charge(&memcg->kmem, nr_pages, &counter)) { + memcg = get_mem_cgroup_from_objcg(objcg); - /* - * Enforce __GFP_NOFAIL allocation because callers are not - * prepared to see failures and likely do not have any failure - * handling code. - */ - if (gfp & __GFP_NOFAIL) { - page_counter_charge(&memcg->kmem, nr_pages); - return 0; - } - cancel_charge(memcg, nr_pages); - return -ENOMEM; - } - return 0; -} + ret = try_charge_memcg(memcg, gfp, nr_pages); + if (ret) + goto out; -/** - * __memcg_kmem_uncharge: uncharge a number of kernel pages from a memcg - * @memcg: memcg to uncharge - * @nr_pages: number of pages to uncharge - */ -void __memcg_kmem_uncharge(struct mem_cgroup *memcg, unsigned int nr_pages) -{ - if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) - page_counter_uncharge(&memcg->kmem, nr_pages); + memcg_account_kmem(memcg, nr_pages); +out: + css_put(&memcg->css); - page_counter_uncharge(&memcg->memory, nr_pages); - if (do_memsw_account()) - page_counter_uncharge(&memcg->memsw, nr_pages); + return ret; } /** @@ -3092,18 +3319,18 @@ void __memcg_kmem_uncharge(struct mem_cgroup *memcg, unsigned int nr_pages) */ int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order) { - struct mem_cgroup *memcg; + struct obj_cgroup *objcg; int ret = 0; - memcg = get_mem_cgroup_from_current(); - if (memcg && !mem_cgroup_is_root(memcg)) { - ret = __memcg_kmem_charge(memcg, gfp, 1 << order); + objcg = current_obj_cgroup(); + if (objcg) { + ret = obj_cgroup_charge_pages(objcg, gfp, 1 << order); if (!ret) { - page->mem_cgroup = memcg; - __SetPageKmemcg(page); + obj_cgroup_get(objcg); + page->memcg_data = (unsigned long)objcg | + MEMCG_DATA_KMEM; return 0; } - css_put(&memcg->css); } return ret; } @@ -3115,20 +3342,83 @@ int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order) */ void __memcg_kmem_uncharge_page(struct page *page, int order) { - struct mem_cgroup *memcg = page->mem_cgroup; + struct folio *folio = page_folio(page); + struct obj_cgroup *objcg; unsigned int nr_pages = 1 << order; - if (!memcg) + if (!folio_memcg_kmem(folio)) return; - VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page); - __memcg_kmem_uncharge(memcg, nr_pages); - page->mem_cgroup = NULL; - css_put(&memcg->css); + objcg = __folio_objcg(folio); + obj_cgroup_uncharge_pages(objcg, nr_pages); + folio->memcg_data = 0; + obj_cgroup_put(objcg); +} + +void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat, + enum node_stat_item idx, int nr) +{ + struct memcg_stock_pcp *stock; + struct obj_cgroup *old = NULL; + unsigned long flags; + int *bytes; - /* slab pages do not have PageKmemcg flag set */ - if (PageKmemcg(page)) - __ClearPageKmemcg(page); + local_lock_irqsave(&memcg_stock.stock_lock, flags); + stock = this_cpu_ptr(&memcg_stock); + + /* + * Save vmstat data in stock and skip vmstat array update unless + * accumulating over a page of vmstat data or when pgdat or idx + * changes. + */ + if (READ_ONCE(stock->cached_objcg) != objcg) { + old = drain_obj_stock(stock); + obj_cgroup_get(objcg); + stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes) + ? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0; + WRITE_ONCE(stock->cached_objcg, objcg); + stock->cached_pgdat = pgdat; + } else if (stock->cached_pgdat != pgdat) { + /* Flush the existing cached vmstat data */ + struct pglist_data *oldpg = stock->cached_pgdat; + + if (stock->nr_slab_reclaimable_b) { + mod_objcg_mlstate(objcg, oldpg, NR_SLAB_RECLAIMABLE_B, + stock->nr_slab_reclaimable_b); + stock->nr_slab_reclaimable_b = 0; + } + if (stock->nr_slab_unreclaimable_b) { + mod_objcg_mlstate(objcg, oldpg, NR_SLAB_UNRECLAIMABLE_B, + stock->nr_slab_unreclaimable_b); + stock->nr_slab_unreclaimable_b = 0; + } + stock->cached_pgdat = pgdat; + } + + bytes = (idx == NR_SLAB_RECLAIMABLE_B) ? &stock->nr_slab_reclaimable_b + : &stock->nr_slab_unreclaimable_b; + /* + * Even for large object >= PAGE_SIZE, the vmstat data will still be + * cached locally at least once before pushing it out. + */ + if (!*bytes) { + *bytes = nr; + nr = 0; + } else { + *bytes += nr; + if (abs(*bytes) > PAGE_SIZE) { + nr = *bytes; + *bytes = 0; + } else { + nr = 0; + } + } + if (nr) + mod_objcg_mlstate(objcg, pgdat, idx, nr); + + local_unlock_irqrestore(&memcg_stock.stock_lock, flags); + if (old) + obj_cgroup_put(old); } static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes) @@ -3137,34 +3427,39 @@ static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes) unsigned long flags; bool ret = false; - local_irq_save(flags); + local_lock_irqsave(&memcg_stock.stock_lock, flags); stock = this_cpu_ptr(&memcg_stock); - if (objcg == stock->cached_objcg && stock->nr_bytes >= nr_bytes) { + if (objcg == READ_ONCE(stock->cached_objcg) && stock->nr_bytes >= nr_bytes) { stock->nr_bytes -= nr_bytes; ret = true; } - local_irq_restore(flags); + local_unlock_irqrestore(&memcg_stock.stock_lock, flags); return ret; } -static void drain_obj_stock(struct memcg_stock_pcp *stock) +static struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock) { - struct obj_cgroup *old = stock->cached_objcg; + struct obj_cgroup *old = READ_ONCE(stock->cached_objcg); if (!old) - return; + return NULL; if (stock->nr_bytes) { unsigned int nr_pages = stock->nr_bytes >> PAGE_SHIFT; unsigned int nr_bytes = stock->nr_bytes & (PAGE_SIZE - 1); if (nr_pages) { - rcu_read_lock(); - __memcg_kmem_uncharge(obj_cgroup_memcg(old), nr_pages); - rcu_read_unlock(); + struct mem_cgroup *memcg; + + memcg = get_mem_cgroup_from_objcg(old); + + memcg_account_kmem(memcg, -nr_pages); + __refill_stock(memcg, nr_pages); + + css_put(&memcg->css); } /* @@ -3181,17 +3476,41 @@ static void drain_obj_stock(struct memcg_stock_pcp *stock) stock->nr_bytes = 0; } - obj_cgroup_put(old); - stock->cached_objcg = NULL; + /* + * Flush the vmstat data in current stock + */ + if (stock->nr_slab_reclaimable_b || stock->nr_slab_unreclaimable_b) { + if (stock->nr_slab_reclaimable_b) { + mod_objcg_mlstate(old, stock->cached_pgdat, + NR_SLAB_RECLAIMABLE_B, + stock->nr_slab_reclaimable_b); + stock->nr_slab_reclaimable_b = 0; + } + if (stock->nr_slab_unreclaimable_b) { + mod_objcg_mlstate(old, stock->cached_pgdat, + NR_SLAB_UNRECLAIMABLE_B, + stock->nr_slab_unreclaimable_b); + stock->nr_slab_unreclaimable_b = 0; + } + stock->cached_pgdat = NULL; + } + + WRITE_ONCE(stock->cached_objcg, NULL); + /* + * The `old' objects needs to be released by the caller via + * obj_cgroup_put() outside of memcg_stock_pcp::stock_lock. + */ + return old; } static bool obj_stock_flush_required(struct memcg_stock_pcp *stock, struct mem_cgroup *root_memcg) { + struct obj_cgroup *objcg = READ_ONCE(stock->cached_objcg); struct mem_cgroup *memcg; - if (stock->cached_objcg) { - memcg = obj_cgroup_memcg(stock->cached_objcg); + if (objcg) { + memcg = obj_cgroup_memcg(objcg); if (memcg && mem_cgroup_is_descendant(memcg, root_memcg)) return true; } @@ -3199,31 +3518,42 @@ static bool obj_stock_flush_required(struct memcg_stock_pcp *stock, return false; } -static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes) +static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes, + bool allow_uncharge) { struct memcg_stock_pcp *stock; + struct obj_cgroup *old = NULL; unsigned long flags; + unsigned int nr_pages = 0; - local_irq_save(flags); + local_lock_irqsave(&memcg_stock.stock_lock, flags); stock = this_cpu_ptr(&memcg_stock); - if (stock->cached_objcg != objcg) { /* reset if necessary */ - drain_obj_stock(stock); + if (READ_ONCE(stock->cached_objcg) != objcg) { /* reset if necessary */ + old = drain_obj_stock(stock); obj_cgroup_get(objcg); - stock->cached_objcg = objcg; - stock->nr_bytes = atomic_xchg(&objcg->nr_charged_bytes, 0); + WRITE_ONCE(stock->cached_objcg, objcg); + stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes) + ? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0; + allow_uncharge = true; /* Allow uncharge when objcg changes */ } stock->nr_bytes += nr_bytes; - if (stock->nr_bytes > PAGE_SIZE) - drain_obj_stock(stock); + if (allow_uncharge && (stock->nr_bytes > PAGE_SIZE)) { + nr_pages = stock->nr_bytes >> PAGE_SHIFT; + stock->nr_bytes &= (PAGE_SIZE - 1); + } + + local_unlock_irqrestore(&memcg_stock.stock_lock, flags); + if (old) + obj_cgroup_put(old); - local_irq_restore(flags); + if (nr_pages) + obj_cgroup_uncharge_pages(objcg, nr_pages); } int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size) { - struct mem_cgroup *memcg; unsigned int nr_pages, nr_bytes; int ret; @@ -3231,63 +3561,70 @@ int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size) return 0; /* - * In theory, memcg->nr_charged_bytes can have enough + * In theory, objcg->nr_charged_bytes can have enough * pre-charged bytes to satisfy the allocation. However, - * flushing memcg->nr_charged_bytes requires two atomic - * operations, and memcg->nr_charged_bytes can't be big, - * so it's better to ignore it and try grab some new pages. - * memcg->nr_charged_bytes will be flushed in - * refill_obj_stock(), called from this function or - * independently later. + * flushing objcg->nr_charged_bytes requires two atomic + * operations, and objcg->nr_charged_bytes can't be big. + * The shared objcg->nr_charged_bytes can also become a + * performance bottleneck if all tasks of the same memcg are + * trying to update it. So it's better to ignore it and try + * grab some new pages. The stock's nr_bytes will be flushed to + * objcg->nr_charged_bytes later on when objcg changes. + * + * The stock's nr_bytes may contain enough pre-charged bytes + * to allow one less page from being charged, but we can't rely + * on the pre-charged bytes not being changed outside of + * consume_obj_stock() or refill_obj_stock(). So ignore those + * pre-charged bytes as well when charging pages. To avoid a + * page uncharge right after a page charge, we set the + * allow_uncharge flag to false when calling refill_obj_stock() + * to temporarily allow the pre-charged bytes to exceed the page + * size limit. The maximum reachable value of the pre-charged + * bytes is (sizeof(object) + PAGE_SIZE - 2) if there is no data + * race. */ - rcu_read_lock(); - memcg = obj_cgroup_memcg(objcg); - css_get(&memcg->css); - rcu_read_unlock(); - nr_pages = size >> PAGE_SHIFT; nr_bytes = size & (PAGE_SIZE - 1); if (nr_bytes) nr_pages += 1; - ret = __memcg_kmem_charge(memcg, gfp, nr_pages); + ret = obj_cgroup_charge_pages(objcg, gfp, nr_pages); if (!ret && nr_bytes) - refill_obj_stock(objcg, PAGE_SIZE - nr_bytes); + refill_obj_stock(objcg, PAGE_SIZE - nr_bytes, false); - css_put(&memcg->css); return ret; } void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size) { - refill_obj_stock(objcg, size); + refill_obj_stock(objcg, size, true); } #endif /* CONFIG_MEMCG_KMEM */ -#ifdef CONFIG_TRANSPARENT_HUGEPAGE - /* - * Because tail pages are not marked as "used", set it. We're under - * pgdat->lru_lock and migration entries setup in all page mappings. + * Because page_memcg(head) is not set on tails, set it now. */ -void mem_cgroup_split_huge_fixup(struct page *head) +void split_page_memcg(struct page *head, unsigned int nr) { - struct mem_cgroup *memcg = head->mem_cgroup; + struct folio *folio = page_folio(head); + struct mem_cgroup *memcg = folio_memcg(folio); int i; - if (mem_cgroup_disabled()) + if (mem_cgroup_disabled() || !memcg) return; - for (i = 1; i < HPAGE_PMD_NR; i++) { - css_get(&memcg->css); - head[i].mem_cgroup = memcg; - } + for (i = 1; i < nr; i++) + folio_page(folio, i)->memcg_data = folio->memcg_data; + + if (folio_memcg_kmem(folio)) + obj_cgroup_get_many(__folio_objcg(folio), nr - 1); + else + css_get_many(&memcg->css, nr - 1); } -#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ -#ifdef CONFIG_MEMCG_SWAP +#ifdef CONFIG_SWAP /** * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record. * @entry: swap entry to be moved @@ -3368,8 +3705,8 @@ static int mem_cgroup_resize_max(struct mem_cgroup *memcg, continue; } - if (!try_to_free_mem_cgroup_pages(memcg, 1, - GFP_KERNEL, !memsw)) { + if (!try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, + memsw ? 0 : MEMCG_RECLAIM_MAY_SWAP)) { ret = -EBUSY; break; } @@ -3391,12 +3728,14 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, int loop = 0; struct mem_cgroup_tree_per_node *mctz; unsigned long excess; - unsigned long nr_scanned; + + if (lru_gen_enabled()) + return 0; if (order > 0) return 0; - mctz = soft_limit_tree_node(pgdat->node_id); + mctz = soft_limit_tree.rb_tree_per_node[pgdat->node_id]; /* * Do not even bother to check the largest node if the root @@ -3419,13 +3758,10 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, if (!mz) break; - nr_scanned = 0; reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat, - gfp_mask, &nr_scanned); + gfp_mask, total_scanned); nr_reclaimed += reclaimed; - *total_scanned += nr_scanned; spin_lock_irq(&mctz->lock); - __mem_cgroup_remove_exceeded(mz, mctz); /* * If we failed to reclaim anything from this memory cgroup @@ -3465,22 +3801,6 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, } /* - * 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 responsibility. - */ -static inline bool memcg_has_children(struct mem_cgroup *memcg) -{ - bool ret; - - rcu_read_lock(); - ret = css_next_child(NULL, &memcg->css); - rcu_read_unlock(); - return ret; -} - -/* * Reclaims as many pages from the given memcg as possible. * * Caller is responsible for holding css reference for memcg. @@ -3496,19 +3816,12 @@ static int mem_cgroup_force_empty(struct mem_cgroup *memcg) /* try to free all pages in this cgroup */ while (nr_retries && page_counter_read(&memcg->memory)) { - int progress; - if (signal_pending(current)) return -EINTR; - progress = try_to_free_mem_cgroup_pages(memcg, 1, - GFP_KERNEL, true); - if (!progress) { + if (!try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, + MEMCG_RECLAIM_MAY_SWAP)) nr_retries--; - /* maybe some writeback is necessary */ - congestion_wait(BLK_RW_ASYNC, HZ/10); - } - } return 0; @@ -3528,37 +3841,20 @@ static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of, static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css, struct cftype *cft) { - return mem_cgroup_from_css(css)->use_hierarchy; + return 1; } 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_css(css); - struct mem_cgroup *parent_memcg = mem_cgroup_from_css(memcg->css.parent); - - if (memcg->use_hierarchy == val) + if (val == 1) return 0; - /* - * If parent's use_hierarchy is set, we can't make any modifications - * in the child subtrees. If it is unset, then the change can - * occur, provided the current cgroup has no children. - * - * For the root cgroup, parent_mem is NULL, we allow value to be - * set if there are no children. - */ - if ((!parent_memcg || !parent_memcg->use_hierarchy) && - (val == 1 || val == 0)) { - if (!memcg_has_children(memcg)) - memcg->use_hierarchy = val; - else - retval = -EBUSY; - } else - retval = -EINVAL; + pr_warn_once("Non-hierarchical mode is deprecated. " + "Please report your usecase to linux-mm@kvack.org if you " + "depend on this functionality.\n"); - return retval; + return -EINVAL; } static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) @@ -3566,10 +3862,14 @@ static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) unsigned long val; if (mem_cgroup_is_root(memcg)) { - val = memcg_page_state(memcg, NR_FILE_PAGES) + - memcg_page_state(memcg, NR_ANON_MAPPED); + /* + * Approximate root's usage from global state. This isn't + * perfect, but the root usage was always an approximation. + */ + val = global_node_page_state(NR_FILE_PAGES) + + global_node_page_state(NR_ANON_MAPPED); if (swap) - val += memcg_page_state(memcg, MEMCG_SWAP); + val += total_swap_pages - get_nr_swap_pages(); } else { if (!swap) val = page_counter_read(&memcg->memory); @@ -3624,111 +3924,58 @@ static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css, case RES_FAILCNT: return counter->failcnt; case RES_SOFT_LIMIT: - return (u64)memcg->soft_limit * PAGE_SIZE; + return (u64)READ_ONCE(memcg->soft_limit) * PAGE_SIZE; default: BUG(); } } -static void memcg_flush_percpu_vmstats(struct mem_cgroup *memcg) -{ - unsigned long stat[MEMCG_NR_STAT] = {0}; - struct mem_cgroup *mi; - int node, cpu, i; - - for_each_online_cpu(cpu) - for (i = 0; i < MEMCG_NR_STAT; i++) - stat[i] += per_cpu(memcg->vmstats_percpu->stat[i], cpu); - - for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) - for (i = 0; i < MEMCG_NR_STAT; i++) - atomic_long_add(stat[i], &mi->vmstats[i]); - - for_each_node(node) { - struct mem_cgroup_per_node *pn = memcg->nodeinfo[node]; - struct mem_cgroup_per_node *pi; - - for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) - stat[i] = 0; - - for_each_online_cpu(cpu) - for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) - stat[i] += per_cpu( - pn->lruvec_stat_cpu->count[i], cpu); - - for (pi = pn; pi; pi = parent_nodeinfo(pi, node)) - for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) - atomic_long_add(stat[i], &pi->lruvec_stat[i]); - } -} - -static void memcg_flush_percpu_vmevents(struct mem_cgroup *memcg) +/* + * This function doesn't do anything useful. Its only job is to provide a read + * handler for a file so that cgroup_file_mode() will add read permissions. + */ +static int mem_cgroup_dummy_seq_show(__always_unused struct seq_file *m, + __always_unused void *v) { - unsigned long events[NR_VM_EVENT_ITEMS]; - struct mem_cgroup *mi; - int cpu, i; - - for (i = 0; i < NR_VM_EVENT_ITEMS; i++) - events[i] = 0; - - for_each_online_cpu(cpu) - for (i = 0; i < NR_VM_EVENT_ITEMS; i++) - events[i] += per_cpu(memcg->vmstats_percpu->events[i], - cpu); - - for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) - for (i = 0; i < NR_VM_EVENT_ITEMS; i++) - atomic_long_add(events[i], &mi->vmevents[i]); + return -EINVAL; } #ifdef CONFIG_MEMCG_KMEM static int memcg_online_kmem(struct mem_cgroup *memcg) { struct obj_cgroup *objcg; - int memcg_id; - if (cgroup_memory_nokmem) + if (mem_cgroup_kmem_disabled()) return 0; - BUG_ON(memcg->kmemcg_id >= 0); - BUG_ON(memcg->kmem_state); - - memcg_id = memcg_alloc_cache_id(); - if (memcg_id < 0) - return memcg_id; + if (unlikely(mem_cgroup_is_root(memcg))) + return 0; objcg = obj_cgroup_alloc(); - if (!objcg) { - memcg_free_cache_id(memcg_id); + if (!objcg) return -ENOMEM; - } + objcg->memcg = memcg; rcu_assign_pointer(memcg->objcg, objcg); + obj_cgroup_get(objcg); + memcg->orig_objcg = objcg; - static_branch_enable(&memcg_kmem_enabled_key); + static_branch_enable(&memcg_kmem_online_key); - /* - * A memory cgroup is considered kmem-online as soon as it gets - * kmemcg_id. Setting the id after enabling static branching will - * guarantee no one starts accounting before all call sites are - * patched. - */ - memcg->kmemcg_id = memcg_id; - memcg->kmem_state = KMEM_ONLINE; + memcg->kmemcg_id = memcg->id.id; return 0; } static void memcg_offline_kmem(struct mem_cgroup *memcg) { - struct cgroup_subsys_state *css; - struct mem_cgroup *parent, *child; - int kmemcg_id; + struct mem_cgroup *parent; - if (memcg->kmem_state != KMEM_ONLINE) + if (mem_cgroup_kmem_disabled()) return; - memcg->kmem_state = KMEM_ALLOCATED; + if (unlikely(mem_cgroup_is_root(memcg))) + return; parent = parent_mem_cgroup(memcg); if (!parent) @@ -3736,37 +3983,13 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg) memcg_reparent_objcgs(memcg, parent); - kmemcg_id = memcg->kmemcg_id; - BUG_ON(kmemcg_id < 0); - /* - * Change kmemcg_id of this cgroup and all its descendants to the - * parent's id, and then move all entries from this cgroup's list_lrus - * to ones of the parent. After we have finished, all list_lrus - * corresponding to this cgroup are guaranteed to remain empty. The - * ordering is imposed by list_lru_node->lock taken by - * memcg_drain_all_list_lrus(). + * After we have finished memcg_reparent_objcgs(), all list_lrus + * corresponding to this cgroup are guaranteed to remain empty. + * The ordering is imposed by list_lru_node->lock taken by + * memcg_reparent_list_lrus(). */ - rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */ - css_for_each_descendant_pre(css, &memcg->css) { - child = mem_cgroup_from_css(css); - BUG_ON(child->kmemcg_id != kmemcg_id); - child->kmemcg_id = parent->kmemcg_id; - if (!memcg->use_hierarchy) - break; - } - rcu_read_unlock(); - - memcg_drain_all_list_lrus(kmemcg_id, parent); - - memcg_free_cache_id(kmemcg_id); -} - -static void memcg_free_kmem(struct mem_cgroup *memcg) -{ - /* css_alloc() failed, offlining didn't happen */ - if (unlikely(memcg->kmem_state == KMEM_ONLINE)) - memcg_offline_kmem(memcg); + memcg_reparent_list_lrus(memcg, parent); } #else static int memcg_online_kmem(struct mem_cgroup *memcg) @@ -3776,22 +3999,8 @@ static int memcg_online_kmem(struct mem_cgroup *memcg) static void memcg_offline_kmem(struct mem_cgroup *memcg) { } -static void memcg_free_kmem(struct mem_cgroup *memcg) -{ -} #endif /* CONFIG_MEMCG_KMEM */ -static int memcg_update_kmem_max(struct mem_cgroup *memcg, - unsigned long max) -{ - int ret; - - mutex_lock(&memcg_max_mutex); - ret = page_counter_set_max(&memcg->kmem, max); - mutex_unlock(&memcg_max_mutex); - return ret; -} - static int memcg_update_tcp_max(struct mem_cgroup *memcg, unsigned long max) { int ret; @@ -3858,9 +4067,10 @@ static ssize_t mem_cgroup_write(struct kernfs_open_file *of, break; case _KMEM: pr_warn_once("kmem.limit_in_bytes is deprecated and will be removed. " + "Writing any value to this file has no effect. " "Please report your usecase to linux-mm@kvack.org if you " "depend on this functionality.\n"); - ret = memcg_update_kmem_max(memcg, nr_pages); + ret = 0; break; case _TCP: ret = memcg_update_tcp_max(memcg, nr_pages); @@ -3868,8 +4078,12 @@ static ssize_t mem_cgroup_write(struct kernfs_open_file *of, } break; case RES_SOFT_LIMIT: - memcg->soft_limit = nr_pages; - ret = 0; + if (IS_ENABLED(CONFIG_PREEMPT_RT)) { + ret = -EOPNOTSUPP; + } else { + WRITE_ONCE(memcg->soft_limit, nr_pages); + ret = 0; + } break; } return ret ?: nbytes; @@ -3924,6 +4138,10 @@ static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, { struct mem_cgroup *memcg = mem_cgroup_from_css(css); + pr_warn_once("Cgroup memory moving (move_charge_at_immigrate) is deprecated. " + "Please report your usecase to linux-mm@kvack.org if you " + "depend on this functionality.\n"); + if (val & ~MOVE_MASK) return -EINVAL; @@ -4005,6 +4223,8 @@ static int memcg_numa_stat_show(struct seq_file *m, void *v) int nid; struct mem_cgroup *memcg = mem_cgroup_from_seq(m); + mem_cgroup_flush_stats(memcg); + for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { seq_printf(m, "%s=%lu", stat->name, mem_cgroup_nr_lru_pages(memcg, stat->lru_mask, @@ -4042,7 +4262,12 @@ static const unsigned int memcg1_stats[] = { NR_FILE_MAPPED, NR_FILE_DIRTY, NR_WRITEBACK, + WORKINGSET_REFAULT_ANON, + WORKINGSET_REFAULT_FILE, +#ifdef CONFIG_SWAP MEMCG_SWAP, + NR_SWAPCACHE, +#endif }; static const char *const memcg1_stat_names[] = { @@ -4055,7 +4280,12 @@ static const char *const memcg1_stat_names[] = { "mapped_file", "dirty", "writeback", + "workingset_refault_anon", + "workingset_refault_file", +#ifdef CONFIG_SWAP "swap", + "swapcached", +#endif }; /* Universal VM events cgroup1 shows, original sort order */ @@ -4066,36 +4296,31 @@ static const unsigned int memcg1_events[] = { PGMAJFAULT, }; -static int memcg_stat_show(struct seq_file *m, void *v) +static void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) { - struct mem_cgroup *memcg = mem_cgroup_from_seq(m); unsigned long memory, memsw; struct mem_cgroup *mi; unsigned int i; BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats)); + mem_cgroup_flush_stats(memcg); + for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) { unsigned long nr; - if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account()) - continue; - nr = memcg_page_state_local(memcg, memcg1_stats[i]); -#ifdef CONFIG_TRANSPARENT_HUGEPAGE - if (memcg1_stats[i] == NR_ANON_THPS) - nr *= HPAGE_PMD_NR; -#endif - seq_printf(m, "%s %lu\n", memcg1_stat_names[i], nr * PAGE_SIZE); + nr = memcg_page_state_local_output(memcg, memcg1_stats[i]); + seq_buf_printf(s, "%s %lu\n", memcg1_stat_names[i], nr); } for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) - seq_printf(m, "%s %lu\n", vm_event_name(memcg1_events[i]), - memcg_events_local(memcg, memcg1_events[i])); + seq_buf_printf(s, "%s %lu\n", vm_event_name(memcg1_events[i]), + memcg_events_local(memcg, memcg1_events[i])); for (i = 0; i < NR_LRU_LISTS; i++) - seq_printf(m, "%s %lu\n", lru_list_name(i), - memcg_page_state_local(memcg, NR_LRU_BASE + i) * - PAGE_SIZE); + seq_buf_printf(s, "%s %lu\n", lru_list_name(i), + memcg_page_state_local(memcg, NR_LRU_BASE + i) * + PAGE_SIZE); /* Hierarchical information */ memory = memsw = PAGE_COUNTER_MAX; @@ -4103,29 +4328,28 @@ static int memcg_stat_show(struct seq_file *m, void *v) memory = min(memory, READ_ONCE(mi->memory.max)); memsw = min(memsw, READ_ONCE(mi->memsw.max)); } - seq_printf(m, "hierarchical_memory_limit %llu\n", - (u64)memory * PAGE_SIZE); - if (do_memsw_account()) - seq_printf(m, "hierarchical_memsw_limit %llu\n", - (u64)memsw * PAGE_SIZE); + seq_buf_printf(s, "hierarchical_memory_limit %llu\n", + (u64)memory * PAGE_SIZE); + seq_buf_printf(s, "hierarchical_memsw_limit %llu\n", + (u64)memsw * PAGE_SIZE); for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) { - if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account()) - continue; - seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i], - (u64)memcg_page_state(memcg, memcg1_stats[i]) * - PAGE_SIZE); + unsigned long nr; + + nr = memcg_page_state_output(memcg, memcg1_stats[i]); + seq_buf_printf(s, "total_%s %llu\n", memcg1_stat_names[i], + (u64)nr); } for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) - seq_printf(m, "total_%s %llu\n", - vm_event_name(memcg1_events[i]), - (u64)memcg_events(memcg, memcg1_events[i])); + seq_buf_printf(s, "total_%s %llu\n", + vm_event_name(memcg1_events[i]), + (u64)memcg_events(memcg, memcg1_events[i])); for (i = 0; i < NR_LRU_LISTS; i++) - seq_printf(m, "total_%s %llu\n", lru_list_name(i), - (u64)memcg_page_state(memcg, NR_LRU_BASE + i) * - PAGE_SIZE); + seq_buf_printf(s, "total_%s %llu\n", lru_list_name(i), + (u64)memcg_page_state(memcg, NR_LRU_BASE + i) * + PAGE_SIZE); #ifdef CONFIG_DEBUG_VM { @@ -4135,17 +4359,15 @@ static int memcg_stat_show(struct seq_file *m, void *v) unsigned long file_cost = 0; for_each_online_pgdat(pgdat) { - mz = mem_cgroup_nodeinfo(memcg, pgdat->node_id); + mz = memcg->nodeinfo[pgdat->node_id]; anon_cost += mz->lruvec.anon_cost; file_cost += mz->lruvec.file_cost; } - seq_printf(m, "anon_cost %lu\n", anon_cost); - seq_printf(m, "file_cost %lu\n", file_cost); + seq_buf_printf(s, "anon_cost %lu\n", anon_cost); + seq_buf_printf(s, "file_cost %lu\n", file_cost); } #endif - - return 0; } static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css, @@ -4161,13 +4383,13 @@ static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css, { struct mem_cgroup *memcg = mem_cgroup_from_css(css); - if (val > 100) + if (val > 200) return -EINVAL; - if (css->parent) - memcg->swappiness = val; + if (!mem_cgroup_is_root(memcg)) + WRITE_ONCE(memcg->swappiness, val); else - vm_swappiness = val; + WRITE_ONCE(vm_swappiness, val); return 0; } @@ -4203,7 +4425,7 @@ static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap) * only one element of the array here. */ for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--) - eventfd_signal(t->entries[i].eventfd, 1); + eventfd_signal(t->entries[i].eventfd); /* i = current_threshold + 1 */ i++; @@ -4215,7 +4437,7 @@ static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap) * only one element of the array here. */ for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++) - eventfd_signal(t->entries[i].eventfd, 1); + eventfd_signal(t->entries[i].eventfd); /* Update current_threshold */ t->current_threshold = i - 1; @@ -4255,7 +4477,7 @@ static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg) spin_lock(&memcg_oom_lock); list_for_each_entry(ev, &memcg->oom_notify, list) - eventfd_signal(ev->eventfd, 1); + eventfd_signal(ev->eventfd); spin_unlock(&memcg_oom_lock); return 0; @@ -4474,7 +4696,7 @@ static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg, /* already in OOM ? */ if (memcg->under_oom) - eventfd_signal(eventfd, 1); + eventfd_signal(eventfd); spin_unlock(&memcg_oom_lock); return 0; @@ -4501,7 +4723,7 @@ static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v) { struct mem_cgroup *memcg = mem_cgroup_from_seq(sf); - seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable); + seq_printf(sf, "oom_kill_disable %d\n", READ_ONCE(memcg->oom_kill_disable)); seq_printf(sf, "under_oom %d\n", (bool)memcg->under_oom); seq_printf(sf, "oom_kill %lu\n", atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL])); @@ -4514,10 +4736,10 @@ static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css, struct mem_cgroup *memcg = mem_cgroup_from_css(css); /* cannot set to root cgroup and only 0 and 1 are allowed */ - if (!css->parent || !((val == 0) || (val == 1))) + if (mem_cgroup_is_root(memcg) || !((val == 0) || (val == 1))) return -EINVAL; - memcg->oom_kill_disable = val; + WRITE_ONCE(memcg->oom_kill_disable, val); if (!val) memcg_oom_recover(memcg); @@ -4553,22 +4775,6 @@ struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb) return &memcg->cgwb_domain; } -/* - * idx can be of type enum memcg_stat_item or node_stat_item. - * Keep in sync with memcg_exact_page(). - */ -static unsigned long memcg_exact_page_state(struct mem_cgroup *memcg, int idx) -{ - long x = atomic_long_read(&memcg->vmstats[idx]); - int cpu; - - for_each_online_cpu(cpu) - x += per_cpu_ptr(memcg->vmstats_percpu, cpu)->stat[idx]; - if (x < 0) - x = 0; - return x; -} - /** * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg * @wb: bdi_writeback in question @@ -4594,13 +4800,14 @@ void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages, struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css); struct mem_cgroup *parent; - *pdirty = memcg_exact_page_state(memcg, NR_FILE_DIRTY); + mem_cgroup_flush_stats(memcg); - *pwriteback = memcg_exact_page_state(memcg, NR_WRITEBACK); - *pfilepages = memcg_exact_page_state(memcg, NR_INACTIVE_FILE) + - memcg_exact_page_state(memcg, NR_ACTIVE_FILE); - *pheadroom = PAGE_COUNTER_MAX; + *pdirty = memcg_page_state(memcg, NR_FILE_DIRTY); + *pwriteback = memcg_page_state(memcg, NR_WRITEBACK); + *pfilepages = memcg_page_state(memcg, NR_INACTIVE_FILE) + + memcg_page_state(memcg, NR_ACTIVE_FILE); + *pheadroom = PAGE_COUNTER_MAX; while ((parent = parent_mem_cgroup(memcg))) { unsigned long ceiling = min(READ_ONCE(memcg->memory.max), READ_ONCE(memcg->memory.high)); @@ -4615,7 +4822,7 @@ void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages, * Foreign dirty flushing * * There's an inherent mismatch between memcg and writeback. The former - * trackes ownership per-page while the latter per-inode. This was a + * tracks ownership per-page while the latter per-inode. This was a * deliberate design decision because honoring per-page ownership in the * writeback path is complicated, may lead to higher CPU and IO overheads * and deemed unnecessary given that write-sharing an inode across @@ -4630,9 +4837,9 @@ void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages, * triggering background writeback. A will be slowed down without a way to * make writeback of the dirty pages happen. * - * Conditions like the above can lead to a cgroup getting repatedly and + * Conditions like the above can lead to a cgroup getting repeatedly and * severely throttled after making some progress after each - * dirty_expire_interval while the underyling IO device is almost + * dirty_expire_interval while the underlying IO device is almost * completely idle. * * Solving this problem completely requires matching the ownership tracking @@ -4655,17 +4862,17 @@ void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages, * As being wrong occasionally doesn't matter, updates and accesses to the * records are lockless and racy. */ -void mem_cgroup_track_foreign_dirty_slowpath(struct page *page, +void mem_cgroup_track_foreign_dirty_slowpath(struct folio *folio, struct bdi_writeback *wb) { - struct mem_cgroup *memcg = page->mem_cgroup; + struct mem_cgroup *memcg = folio_memcg(folio); struct memcg_cgwb_frn *frn; u64 now = get_jiffies_64(); u64 oldest_at = now; int oldest = -1; int i; - trace_track_foreign_dirty(page, wb); + trace_track_foreign_dirty(folio, wb); /* * Pick the slot to use. If there is already a slot for @wb, keep @@ -4728,7 +4935,7 @@ void mem_cgroup_flush_foreign(struct bdi_writeback *wb) atomic_read(&frn->done.cnt) == 1) { frn->at = 0; trace_flush_foreign(wb, frn->bdi_id, frn->memcg_id); - cgroup_writeback_by_id(frn->bdi_id, frn->memcg_id, 0, + cgroup_writeback_by_id(frn->bdi_id, frn->memcg_id, WB_REASON_FOREIGN_FLUSH, &frn->done); } @@ -4781,7 +4988,7 @@ static void memcg_event_remove(struct work_struct *work) event->unregister_event(memcg, event->eventfd); /* Notify userspace the event is going away. */ - eventfd_signal(event->eventfd, 1); + eventfd_signal(event->eventfd); eventfd_ctx_put(event->eventfd); kfree(event); @@ -4854,10 +5061,14 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of, unsigned int efd, cfd; struct fd efile; struct fd cfile; + struct dentry *cdentry; const char *name; char *endp; int ret; + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + return -EOPNOTSUPP; + buf = strstrip(buf); efd = simple_strtoul(buf, &endp, 10); @@ -4900,11 +5111,21 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of, /* 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); + ret = file_permission(cfile.file, MAY_READ); if (ret < 0) goto out_put_cfile; /* + * The control file must be a regular cgroup1 file. As a regular cgroup + * file can't be renamed, it's safe to access its name afterwards. + */ + cdentry = cfile.file->f_path.dentry; + if (cdentry->d_sb->s_type != &cgroup_fs_type || !d_is_reg(cdentry)) { + ret = -EINVAL; + 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 @@ -4912,7 +5133,7 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of, * * DO NOT ADD NEW FILES. */ - name = cfile.file->f_path.dentry->d_name.name; + name = cdentry->d_name.name; if (!strcmp(name, "memory.usage_in_bytes")) { event->register_event = mem_cgroup_usage_register_event; @@ -4936,7 +5157,7 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of, * 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_path.dentry->d_parent, + cfile_css = css_tryget_online_from_dir(cdentry->d_parent, &memory_cgrp_subsys); ret = -EINVAL; if (IS_ERR(cfile_css)) @@ -4952,9 +5173,9 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of, vfs_poll(efile.file, &event->pt); - spin_lock(&memcg->event_list_lock); + spin_lock_irq(&memcg->event_list_lock); list_add(&event->list, &memcg->event_list); - spin_unlock(&memcg->event_list_lock); + spin_unlock_irq(&memcg->event_list_lock); fdput(cfile); fdput(efile); @@ -4975,6 +5196,19 @@ out_kfree: return ret; } +#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_SLUB_DEBUG) +static int mem_cgroup_slab_show(struct seq_file *m, void *p) +{ + /* + * Deprecated. + * Please, take a look at tools/cgroup/memcg_slabinfo.py . + */ + return 0; +} +#endif + +static int memory_stat_show(struct seq_file *m, void *v); + static struct cftype mem_cgroup_legacy_files[] = { { .name = "usage_in_bytes", @@ -5007,7 +5241,7 @@ static struct cftype mem_cgroup_legacy_files[] = { }, { .name = "stat", - .seq_show = memcg_stat_show, + .seq_show = memory_stat_show, }, { .name = "force_empty", @@ -5037,10 +5271,10 @@ static struct cftype mem_cgroup_legacy_files[] = { .name = "oom_control", .seq_show = mem_cgroup_oom_control_read, .write_u64 = mem_cgroup_oom_control_write, - .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL), }, { .name = "pressure_level", + .seq_show = mem_cgroup_dummy_seq_show, }, #ifdef CONFIG_NUMA { @@ -5071,11 +5305,10 @@ static struct cftype mem_cgroup_legacy_files[] = { .write = mem_cgroup_reset, .read_u64 = mem_cgroup_read_u64, }, -#if defined(CONFIG_MEMCG_KMEM) && \ - (defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)) +#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_SLUB_DEBUG) { .name = "kmem.slabinfo", - .seq_show = memcg_slab_show, + .seq_show = mem_cgroup_slab_show, }, #endif { @@ -5128,6 +5361,7 @@ static struct cftype mem_cgroup_legacy_files[] = { * those references are manageable from userspace. */ +#define MEM_CGROUP_ID_MAX ((1UL << MEM_CGROUP_ID_SHIFT) - 1) static DEFINE_IDR(mem_cgroup_idr); static void mem_cgroup_id_remove(struct mem_cgroup *memcg) @@ -5171,42 +5405,45 @@ struct mem_cgroup *mem_cgroup_from_id(unsigned short id) return idr_find(&mem_cgroup_idr, id); } +#ifdef CONFIG_SHRINKER_DEBUG +struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino) +{ + struct cgroup *cgrp; + struct cgroup_subsys_state *css; + struct mem_cgroup *memcg; + + cgrp = cgroup_get_from_id(ino); + if (IS_ERR(cgrp)) + return ERR_CAST(cgrp); + + css = cgroup_get_e_css(cgrp, &memory_cgrp_subsys); + if (css) + memcg = container_of(css, struct mem_cgroup, css); + else + memcg = ERR_PTR(-ENOENT); + + cgroup_put(cgrp); + + return memcg; +} +#endif + static int alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node) { struct mem_cgroup_per_node *pn; - int tmp = node; - /* - * This routine is called against possible nodes. - * But it's BUG to call kmalloc() against offline node. - * - * TODO: this routine can waste much memory for nodes which will - * never be onlined. It's better to use memory hotplug callback - * function. - */ - if (!node_state(node, N_NORMAL_MEMORY)) - tmp = -1; - pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp); - if (!pn) - return 1; - pn->lruvec_stat_local = alloc_percpu_gfp(struct lruvec_stat, - GFP_KERNEL_ACCOUNT); - if (!pn->lruvec_stat_local) { - kfree(pn); + pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, node); + if (!pn) return 1; - } - pn->lruvec_stat_cpu = alloc_percpu_gfp(struct lruvec_stat, - GFP_KERNEL_ACCOUNT); - if (!pn->lruvec_stat_cpu) { - free_percpu(pn->lruvec_stat_local); + pn->lruvec_stats_percpu = alloc_percpu_gfp(struct lruvec_stats_percpu, + GFP_KERNEL_ACCOUNT); + if (!pn->lruvec_stats_percpu) { kfree(pn); return 1; } lruvec_init(&pn->lruvec); - pn->usage_in_excess = 0; - pn->on_tree = false; pn->memcg = memcg; memcg->nodeinfo[node] = pn; @@ -5220,8 +5457,7 @@ static void free_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node) if (!pn) return; - free_percpu(pn->lruvec_stat_cpu); - free_percpu(pn->lruvec_stat_local); + free_percpu(pn->lruvec_stats_percpu); kfree(pn); } @@ -5229,51 +5465,44 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg) { int node; + if (memcg->orig_objcg) + obj_cgroup_put(memcg->orig_objcg); + for_each_node(node) free_mem_cgroup_per_node_info(memcg, node); + kfree(memcg->vmstats); free_percpu(memcg->vmstats_percpu); - free_percpu(memcg->vmstats_local); kfree(memcg); } static void mem_cgroup_free(struct mem_cgroup *memcg) { + lru_gen_exit_memcg(memcg); memcg_wb_domain_exit(memcg); - /* - * Flush percpu vmstats and vmevents to guarantee the value correctness - * on parent's and all ancestor levels. - */ - memcg_flush_percpu_vmstats(memcg); - memcg_flush_percpu_vmevents(memcg); __mem_cgroup_free(memcg); } -static struct mem_cgroup *mem_cgroup_alloc(void) +static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent) { + struct memcg_vmstats_percpu *statc, *pstatc; struct mem_cgroup *memcg; - unsigned int size; - int node; + int node, cpu; int __maybe_unused i; long error = -ENOMEM; - size = sizeof(struct mem_cgroup); - size += nr_node_ids * sizeof(struct mem_cgroup_per_node *); - - memcg = kzalloc(size, GFP_KERNEL); + memcg = kzalloc(struct_size(memcg, nodeinfo, nr_node_ids), GFP_KERNEL); if (!memcg) return ERR_PTR(error); memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL, - 1, MEM_CGROUP_ID_MAX, - GFP_KERNEL); + 1, MEM_CGROUP_ID_MAX + 1, GFP_KERNEL); if (memcg->id.id < 0) { error = memcg->id.id; goto fail; } - memcg->vmstats_local = alloc_percpu_gfp(struct memcg_vmstats_percpu, - GFP_KERNEL_ACCOUNT); - if (!memcg->vmstats_local) + memcg->vmstats = kzalloc(sizeof(struct memcg_vmstats), GFP_KERNEL); + if (!memcg->vmstats) goto fail; memcg->vmstats_percpu = alloc_percpu_gfp(struct memcg_vmstats_percpu, @@ -5281,6 +5510,14 @@ static struct mem_cgroup *mem_cgroup_alloc(void) if (!memcg->vmstats_percpu) goto fail; + for_each_possible_cpu(cpu) { + if (parent) + pstatc = per_cpu_ptr(parent->vmstats_percpu, cpu); + statc = per_cpu_ptr(memcg->vmstats_percpu, cpu); + statc->parent = parent ? pstatc : NULL; + statc->vmstats = memcg->vmstats; + } + for_each_node(node) if (alloc_mem_cgroup_per_node_info(memcg, node)) goto fail; @@ -5311,7 +5548,7 @@ static struct mem_cgroup *mem_cgroup_alloc(void) INIT_LIST_HEAD(&memcg->deferred_split_queue.split_queue); memcg->deferred_split_queue.split_queue_len = 0; #endif - idr_replace(&mem_cgroup_idr, memcg, memcg->id.id); + lru_gen_init_memcg(memcg); return memcg; fail: mem_cgroup_id_remove(memcg); @@ -5324,79 +5561,93 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) { struct mem_cgroup *parent = mem_cgroup_from_css(parent_css); struct mem_cgroup *memcg, *old_memcg; - long error = -ENOMEM; old_memcg = set_active_memcg(parent); - memcg = mem_cgroup_alloc(); + memcg = mem_cgroup_alloc(parent); set_active_memcg(old_memcg); if (IS_ERR(memcg)) return ERR_CAST(memcg); page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX); - memcg->soft_limit = PAGE_COUNTER_MAX; + WRITE_ONCE(memcg->soft_limit, PAGE_COUNTER_MAX); +#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP) + memcg->zswap_max = PAGE_COUNTER_MAX; + WRITE_ONCE(memcg->zswap_writeback, + !parent || READ_ONCE(parent->zswap_writeback)); +#endif page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX); if (parent) { - memcg->swappiness = mem_cgroup_swappiness(parent); - memcg->oom_kill_disable = parent->oom_kill_disable; - } - if (parent && parent->use_hierarchy) { - memcg->use_hierarchy = true; + WRITE_ONCE(memcg->swappiness, mem_cgroup_swappiness(parent)); + WRITE_ONCE(memcg->oom_kill_disable, READ_ONCE(parent->oom_kill_disable)); + page_counter_init(&memcg->memory, &parent->memory); page_counter_init(&memcg->swap, &parent->swap); page_counter_init(&memcg->kmem, &parent->kmem); page_counter_init(&memcg->tcpmem, &parent->tcpmem); } else { + init_memcg_events(); page_counter_init(&memcg->memory, NULL); page_counter_init(&memcg->swap, NULL); page_counter_init(&memcg->kmem, NULL); page_counter_init(&memcg->tcpmem, NULL); - /* - * Deeper hierachy with use_hierarchy == false doesn't make - * much sense so let cgroup subsystem know about this - * unfortunate state in our controller. - */ - if (parent != root_mem_cgroup) - memory_cgrp_subsys.broken_hierarchy = true; - } - /* The following stuff does not apply to the root */ - if (!parent) { root_mem_cgroup = memcg; return &memcg->css; } - error = memcg_online_kmem(memcg); - if (error) - goto fail; - if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket) static_branch_inc(&memcg_sockets_enabled_key); +#if defined(CONFIG_MEMCG_KMEM) + if (!cgroup_memory_nobpf) + static_branch_inc(&memcg_bpf_enabled_key); +#endif + return &memcg->css; -fail: - mem_cgroup_id_remove(memcg); - mem_cgroup_free(memcg); - return ERR_PTR(error); } static int mem_cgroup_css_online(struct cgroup_subsys_state *css) { struct mem_cgroup *memcg = mem_cgroup_from_css(css); + if (memcg_online_kmem(memcg)) + goto remove_id; + /* - * A memcg must be visible for memcg_expand_shrinker_maps() + * A memcg must be visible for expand_shrinker_info() * by the time the maps are allocated. So, we allocate maps * here, when for_each_mem_cgroup() can't skip it. */ - if (memcg_alloc_shrinker_maps(memcg)) { - mem_cgroup_id_remove(memcg); - return -ENOMEM; - } + if (alloc_shrinker_info(memcg)) + goto offline_kmem; + + if (unlikely(mem_cgroup_is_root(memcg))) + queue_delayed_work(system_unbound_wq, &stats_flush_dwork, + FLUSH_TIME); + lru_gen_online_memcg(memcg); /* Online state pins memcg ID, memcg ID pins CSS */ refcount_set(&memcg->id.ref, 1); css_get(css); + + /* + * Ensure mem_cgroup_from_id() works once we're fully online. + * + * We could do this earlier and require callers to filter with + * css_tryget_online(). But right now there are no users that + * need earlier access, and the workingset code relies on the + * cgroup tree linkage (mem_cgroup_get_nr_swap_pages()). So + * publish it here at the end of onlining. This matches the + * regular ID destruction during offlining. + */ + idr_replace(&mem_cgroup_idr, memcg, memcg->id.id); + return 0; +offline_kmem: + memcg_offline_kmem(memcg); +remove_id: + mem_cgroup_id_remove(memcg); + return -ENOMEM; } static void mem_cgroup_css_offline(struct cgroup_subsys_state *css) @@ -5409,18 +5660,22 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css) * Notify userspace about cgroup removing only after rmdir of cgroup * directory to avoid race between userspace and kernelspace. */ - spin_lock(&memcg->event_list_lock); + spin_lock_irq(&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); + spin_unlock_irq(&memcg->event_list_lock); page_counter_set_min(&memcg->memory, 0); page_counter_set_low(&memcg->memory, 0); + zswap_memcg_offline_cleanup(memcg); + memcg_offline_kmem(memcg); + reparent_shrinker_deferred(memcg); wb_memcg_offline(memcg); + lru_gen_offline_memcg(memcg); drain_all_stock(memcg); @@ -5432,6 +5687,7 @@ static void mem_cgroup_css_released(struct cgroup_subsys_state *css) struct mem_cgroup *memcg = mem_cgroup_from_css(css); invalidate_reclaim_iterators(memcg); + lru_gen_release_memcg(memcg); } static void mem_cgroup_css_free(struct cgroup_subsys_state *css) @@ -5449,11 +5705,15 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css) if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_active) static_branch_dec(&memcg_sockets_enabled_key); +#if defined(CONFIG_MEMCG_KMEM) + if (!cgroup_memory_nobpf) + static_branch_dec(&memcg_bpf_enabled_key); +#endif + vmpressure_cleanup(&memcg->vmpressure); cancel_work_sync(&memcg->high_work); mem_cgroup_remove_from_trees(memcg); - memcg_free_shrinker_maps(memcg); - memcg_free_kmem(memcg); + free_shrinker_info(memcg); mem_cgroup_free(memcg); } @@ -5481,11 +5741,113 @@ static void mem_cgroup_css_reset(struct cgroup_subsys_state *css) page_counter_set_min(&memcg->memory, 0); page_counter_set_low(&memcg->memory, 0); page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX); - memcg->soft_limit = PAGE_COUNTER_MAX; + WRITE_ONCE(memcg->soft_limit, PAGE_COUNTER_MAX); page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX); memcg_wb_domain_size_changed(memcg); } +static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + struct mem_cgroup *parent = parent_mem_cgroup(memcg); + struct memcg_vmstats_percpu *statc; + long delta, delta_cpu, v; + int i, nid; + + statc = per_cpu_ptr(memcg->vmstats_percpu, cpu); + + for (i = 0; i < MEMCG_NR_STAT; i++) { + /* + * Collect the aggregated propagation counts of groups + * below us. We're in a per-cpu loop here and this is + * a global counter, so the first cycle will get them. + */ + delta = memcg->vmstats->state_pending[i]; + if (delta) + memcg->vmstats->state_pending[i] = 0; + + /* Add CPU changes on this level since the last flush */ + delta_cpu = 0; + v = READ_ONCE(statc->state[i]); + if (v != statc->state_prev[i]) { + delta_cpu = v - statc->state_prev[i]; + delta += delta_cpu; + statc->state_prev[i] = v; + } + + /* Aggregate counts on this level and propagate upwards */ + if (delta_cpu) + memcg->vmstats->state_local[i] += delta_cpu; + + if (delta) { + memcg->vmstats->state[i] += delta; + if (parent) + parent->vmstats->state_pending[i] += delta; + } + } + + for (i = 0; i < NR_MEMCG_EVENTS; i++) { + delta = memcg->vmstats->events_pending[i]; + if (delta) + memcg->vmstats->events_pending[i] = 0; + + delta_cpu = 0; + v = READ_ONCE(statc->events[i]); + if (v != statc->events_prev[i]) { + delta_cpu = v - statc->events_prev[i]; + delta += delta_cpu; + statc->events_prev[i] = v; + } + + if (delta_cpu) + memcg->vmstats->events_local[i] += delta_cpu; + + if (delta) { + memcg->vmstats->events[i] += delta; + if (parent) + parent->vmstats->events_pending[i] += delta; + } + } + + for_each_node_state(nid, N_MEMORY) { + struct mem_cgroup_per_node *pn = memcg->nodeinfo[nid]; + struct mem_cgroup_per_node *ppn = NULL; + struct lruvec_stats_percpu *lstatc; + + if (parent) + ppn = parent->nodeinfo[nid]; + + lstatc = per_cpu_ptr(pn->lruvec_stats_percpu, cpu); + + for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) { + delta = pn->lruvec_stats.state_pending[i]; + if (delta) + pn->lruvec_stats.state_pending[i] = 0; + + delta_cpu = 0; + v = READ_ONCE(lstatc->state[i]); + if (v != lstatc->state_prev[i]) { + delta_cpu = v - lstatc->state_prev[i]; + delta += delta_cpu; + lstatc->state_prev[i] = v; + } + + if (delta_cpu) + pn->lruvec_stats.state_local[i] += delta_cpu; + + if (delta) { + pn->lruvec_stats.state[i] += delta; + if (ppn) + ppn->lruvec_stats.state_pending[i] += delta; + } + } + } + statc->stats_updates = 0; + /* We are in a per-cpu loop here, only do the atomic write once */ + if (atomic64_read(&memcg->vmstats->stats_updates)) + atomic64_set(&memcg->vmstats->stats_updates, 0); +} + #ifdef CONFIG_MMU /* Handlers for move charge at task migration. */ static int mem_cgroup_do_precharge(unsigned long count) @@ -5527,7 +5889,7 @@ static struct page *mc_handle_present_pte(struct vm_area_struct *vma, { struct page *page = vm_normal_page(vma, addr, ptent); - if (!page || !page_mapped(page)) + if (!page) return NULL; if (PageAnon(page)) { if (!(mc.flags & MOVE_ANON)) @@ -5536,8 +5898,7 @@ static struct page *mc_handle_present_pte(struct vm_area_struct *vma, if (!(mc.flags & MOVE_FILE)) return NULL; } - if (!get_page_unless_zero(page)) - return NULL; + get_page(page); return page; } @@ -5553,17 +5914,12 @@ static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, return NULL; /* - * Handle MEMORY_DEVICE_PRIVATE which are ZONE_DEVICE page belonging to - * a device and because they are not accessible by CPU they are store - * as special swap entry in the CPU page table. + * Handle device private pages that are not accessible by the CPU, but + * stored as special swap entries in the page table. */ if (is_device_private_entry(ent)) { - page = device_private_entry_to_page(ent); - /* - * MEMORY_DEVICE_PRIVATE means ZONE_DEVICE page and which have - * a refcount of 1 when free (unlike normal page) - */ - if (!page_ref_add_unless(page, 1, 1)) + page = pfn_swap_entry_to_page(ent); + if (!get_page_unless_zero(page)) return NULL; return page; } @@ -5572,7 +5928,7 @@ static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, return NULL; /* - * Because lookup_swap_cache() updates some statistics counter, + * Because swap_cache_get_folio() updates some statistics counter, * we call find_get_page() with swapper_space directly. */ page = find_get_page(swap_address_space(ent), swp_offset(ent)); @@ -5589,17 +5945,23 @@ static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, #endif static struct page *mc_handle_file_pte(struct vm_area_struct *vma, - unsigned long addr, pte_t ptent, swp_entry_t *entry) + unsigned long addr, pte_t ptent) { + unsigned long index; + struct folio *folio; + if (!vma->vm_file) /* anonymous vma */ return NULL; if (!(mc.flags & MOVE_FILE)) return NULL; - /* page is moved even if it's not RSS of this task(page-faulted). */ + /* folio is moved even if it's not RSS of this task(page-faulted). */ /* shmem/tmpfs may report page out on swap: account for that too. */ - return find_get_incore_page(vma->vm_file->f_mapping, - linear_page_index(vma, addr)); + index = linear_page_index(vma, addr); + folio = filemap_get_incore_folio(vma->vm_file->f_mapping, index); + if (IS_ERR(folio)) + return NULL; + return folio_file_page(folio, index); } /** @@ -5609,7 +5971,7 @@ static struct page *mc_handle_file_pte(struct vm_area_struct *vma, * @from: mem_cgroup which the page is moved from. * @to: mem_cgroup which the page is moved to. @from != @to. * - * The caller must make sure the page is not on LRU (isolate_page() is useful.) + * The page must be locked and not on the LRU. * * This function doesn't do "charge" to new cgroup and doesn't do "uncharge" * from old cgroup. @@ -5619,61 +5981,54 @@ static int mem_cgroup_move_account(struct page *page, struct mem_cgroup *from, struct mem_cgroup *to) { + struct folio *folio = page_folio(page); struct lruvec *from_vec, *to_vec; struct pglist_data *pgdat; - unsigned int nr_pages = compound ? thp_nr_pages(page) : 1; - int ret; + unsigned int nr_pages = compound ? folio_nr_pages(folio) : 1; + int nid, ret; VM_BUG_ON(from == to); - VM_BUG_ON_PAGE(PageLRU(page), page); - VM_BUG_ON(compound && !PageTransHuge(page)); - - /* - * Prevent mem_cgroup_migrate() from looking at - * page->mem_cgroup of its source page while we change it. - */ - ret = -EBUSY; - if (!trylock_page(page)) - goto out; + VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); + VM_BUG_ON_FOLIO(folio_test_lru(folio), folio); + VM_BUG_ON(compound && !folio_test_large(folio)); ret = -EINVAL; - if (page->mem_cgroup != from) - goto out_unlock; + if (folio_memcg(folio) != from) + goto out; - pgdat = page_pgdat(page); + pgdat = folio_pgdat(folio); from_vec = mem_cgroup_lruvec(from, pgdat); to_vec = mem_cgroup_lruvec(to, pgdat); - lock_page_memcg(page); + folio_memcg_lock(folio); - if (PageAnon(page)) { - if (page_mapped(page)) { + if (folio_test_anon(folio)) { + if (folio_mapped(folio)) { __mod_lruvec_state(from_vec, NR_ANON_MAPPED, -nr_pages); __mod_lruvec_state(to_vec, NR_ANON_MAPPED, nr_pages); - if (PageTransHuge(page)) { + if (folio_test_pmd_mappable(folio)) { __mod_lruvec_state(from_vec, NR_ANON_THPS, -nr_pages); __mod_lruvec_state(to_vec, NR_ANON_THPS, nr_pages); } - } } else { __mod_lruvec_state(from_vec, NR_FILE_PAGES, -nr_pages); __mod_lruvec_state(to_vec, NR_FILE_PAGES, nr_pages); - if (PageSwapBacked(page)) { + if (folio_test_swapbacked(folio)) { __mod_lruvec_state(from_vec, NR_SHMEM, -nr_pages); __mod_lruvec_state(to_vec, NR_SHMEM, nr_pages); } - if (page_mapped(page)) { + if (folio_mapped(folio)) { __mod_lruvec_state(from_vec, NR_FILE_MAPPED, -nr_pages); __mod_lruvec_state(to_vec, NR_FILE_MAPPED, nr_pages); } - if (PageDirty(page)) { - struct address_space *mapping = page_mapping(page); + if (folio_test_dirty(folio)) { + struct address_space *mapping = folio_mapping(folio); if (mapping_can_writeback(mapping)) { __mod_lruvec_state(from_vec, NR_FILE_DIRTY, @@ -5684,7 +6039,13 @@ static int mem_cgroup_move_account(struct page *page, } } - if (PageWriteback(page)) { +#ifdef CONFIG_SWAP + if (folio_test_swapcache(folio)) { + __mod_lruvec_state(from_vec, NR_SWAPCACHE, -nr_pages); + __mod_lruvec_state(to_vec, NR_SWAPCACHE, nr_pages); + } +#endif + if (folio_test_writeback(folio)) { __mod_lruvec_state(from_vec, NR_WRITEBACK, -nr_pages); __mod_lruvec_state(to_vec, NR_WRITEBACK, nr_pages); } @@ -5692,13 +6053,13 @@ static int mem_cgroup_move_account(struct page *page, /* * All state has been migrated, let's switch to the new memcg. * - * It is safe to change page->mem_cgroup here because the page + * It is safe to change page's memcg here because the page * is referenced, charged, isolated, and locked: we can't race * with (un)charging, migration, LRU putback, or anything else - * that would rely on a stable page->mem_cgroup. + * that would rely on a stable page's memory cgroup. * - * Note that lock_page_memcg is a memcg lock, not a page lock, - * to save space. As soon as we switch page->mem_cgroup to a + * Note that folio_memcg_lock is a memcg lock, not a page lock, + * to save space. As soon as we switch page's memory cgroup to a * new memcg that isn't locked, the above state can change * concurrently again. Make sure we're truly done with it. */ @@ -5707,20 +6068,19 @@ static int mem_cgroup_move_account(struct page *page, css_get(&to->css); css_put(&from->css); - page->mem_cgroup = to; + folio->memcg_data = (unsigned long)to; - __unlock_page_memcg(from); + __folio_memcg_unlock(from); ret = 0; + nid = folio_nid(folio); local_irq_disable(); - mem_cgroup_charge_statistics(to, page, nr_pages); - memcg_check_events(to, page); - mem_cgroup_charge_statistics(from, page, -nr_pages); - memcg_check_events(from, page); + mem_cgroup_charge_statistics(to, nr_pages); + memcg_check_events(to, nid); + mem_cgroup_charge_statistics(from, -nr_pages); + memcg_check_events(from, nid); local_irq_enable(); -out_unlock: - unlock_page(page); out: return ret; } @@ -5732,25 +6092,20 @@ out: * @ptent: the pte to be checked * @target: the pointer the target page or swap ent will be stored(can be NULL) * - * Returns - * 0(MC_TARGET_NONE): if the pte is not a target for move charge. - * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for - * move charge. if @target is not NULL, the page is stored in target->page - * with extra refcnt got(Callers should handle it). - * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a - * target for charge migration. if @target is not NULL, the entry is stored - * in target->ent. - * 3(MC_TARGET_DEVICE): like MC_TARGET_PAGE but page is MEMORY_DEVICE_PRIVATE - * (so ZONE_DEVICE page and thus not on the lru). - * For now we such page is charge like a regular page would be as for all - * intent and purposes it is just special memory taking the place of a - * regular page. - * - * See Documentations/vm/hmm.txt and include/linux/hmm.h - * - * Called with pte lock held. + * Context: Called with pte lock held. + * Return: + * * MC_TARGET_NONE - If the pte is not a target for move charge. + * * MC_TARGET_PAGE - If the page corresponding to this pte is a target for + * move charge. If @target is not NULL, the page is stored in target->page + * with extra refcnt taken (Caller should release it). + * * MC_TARGET_SWAP - If the swap entry corresponding to this pte is a + * target for charge migration. If @target is not NULL, the entry is + * stored in target->ent. + * * MC_TARGET_DEVICE - Like MC_TARGET_PAGE but page is device memory and + * thus not on the lru. For now such page is charged like a regular page + * would be as it is just special memory taking the place of a regular page. + * See Documentations/vm/hmm.txt and include/linux/hmm.h */ - static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma, unsigned long addr, pte_t ptent, union mc_target *target) { @@ -5760,10 +6115,37 @@ static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma, if (pte_present(ptent)) page = mc_handle_present_pte(vma, addr, ptent); + else if (pte_none_mostly(ptent)) + /* + * PTE markers should be treated as a none pte here, separated + * from other swap handling below. + */ + page = mc_handle_file_pte(vma, addr, ptent); else if (is_swap_pte(ptent)) page = mc_handle_swap_pte(vma, ptent, &ent); - else if (pte_none(ptent)) - page = mc_handle_file_pte(vma, addr, ptent, &ent); + + if (target && page) { + if (!trylock_page(page)) { + put_page(page); + return ret; + } + /* + * page_mapped() must be stable during the move. This + * pte is locked, so if it's present, the page cannot + * become unmapped. If it isn't, we have only partial + * control over the mapped state: the page lock will + * prevent new faults against pagecache and swapcache, + * so an unmapped page cannot become mapped. However, + * if the page is already mapped elsewhere, it can + * unmap, and there is nothing we can do about it. + * Alas, skip moving the page in this case. + */ + if (!pte_present(ptent) && page_mapped(page)) { + unlock_page(page); + put_page(page); + return ret; + } + } if (!page && !ent.val) return ret; @@ -5773,15 +6155,19 @@ static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma, * mem_cgroup_move_account() checks the page is valid or * not under LRU exclusion. */ - if (page->mem_cgroup == mc.from) { + if (page_memcg(page) == mc.from) { ret = MC_TARGET_PAGE; - if (is_device_private_page(page)) + if (is_device_private_page(page) || + is_device_coherent_page(page)) ret = MC_TARGET_DEVICE; if (target) target->page = page; } - if (!ret || !target) + if (!ret || !target) { + if (target) + unlock_page(page); put_page(page); + } } /* * There is a swap entry and a page doesn't exist or isn't charged. @@ -5817,10 +6203,14 @@ static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma, VM_BUG_ON_PAGE(!page || !PageHead(page), page); if (!(mc.flags & MOVE_ANON)) return ret; - if (page->mem_cgroup == mc.from) { + if (page_memcg(page) == mc.from) { ret = MC_TARGET_PAGE; if (target) { get_page(page); + if (!trylock_page(page)) { + put_page(page); + return MC_TARGET_NONE; + } target->page = page; } } @@ -5855,11 +6245,11 @@ static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, return 0; } - if (pmd_trans_unstable(pmd)) - return 0; pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + if (!pte) + return 0; for (; addr != end; pte++, addr += PAGE_SIZE) - if (get_mctgt_type(vma, addr, *pte, NULL)) + if (get_mctgt_type(vma, addr, ptep_get(pte), NULL)) mc.precharge++; /* increment precharge temporarily */ pte_unmap_unlock(pte - 1, ptl); cond_resched(); @@ -5869,6 +6259,7 @@ static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, static const struct mm_walk_ops precharge_walk_ops = { .pmd_entry = mem_cgroup_count_precharge_pte_range, + .walk_lock = PGWALK_RDLOCK, }; static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm) @@ -5876,7 +6267,7 @@ static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm) unsigned long precharge; mmap_read_lock(mm); - walk_page_range(mm, 0, mm->highest_vm_end, &precharge_walk_ops, NULL); + walk_page_range(mm, 0, ULONG_MAX, &precharge_walk_ops, NULL); mmap_read_unlock(mm); precharge = mc.precharge; @@ -5902,7 +6293,7 @@ static void __mem_cgroup_clear_mc(void) /* we must uncharge all the leftover precharges from mc.to */ if (mc.precharge) { - cancel_charge(mc.to, mc.precharge); + mem_cgroup_cancel_charge(mc.to, mc.precharge); mc.precharge = 0; } /* @@ -5910,7 +6301,7 @@ static void __mem_cgroup_clear_mc(void) * we must uncharge here. */ if (mc.moved_charge) { - cancel_charge(mc.from, mc.moved_charge); + mem_cgroup_cancel_charge(mc.from, mc.moved_charge); mc.moved_charge = 0; } /* we must fixup refcnts and charges */ @@ -5984,7 +6375,7 @@ static int mem_cgroup_can_attach(struct cgroup_taskset *tset) return 0; /* - * We are now commited to this value whatever it is. Changes in this + * We are now committed to this value whatever it is. Changes in this * tunable will only affect upcoming migrations, not the current one. * So we need to save it, and keep it going. */ @@ -6051,7 +6442,7 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, target_type = get_mctgt_type_thp(vma, addr, *pmd, &target); if (target_type == MC_TARGET_PAGE) { page = target.page; - if (!isolate_lru_page(page)) { + if (isolate_lru_page(page)) { if (!mem_cgroup_move_account(page, true, mc.from, mc.to)) { mc.precharge -= HPAGE_PMD_NR; @@ -6059,6 +6450,7 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, } putback_lru_page(page); } + unlock_page(page); put_page(page); } else if (target_type == MC_TARGET_DEVICE) { page = target.page; @@ -6067,18 +6459,19 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, mc.precharge -= HPAGE_PMD_NR; mc.moved_charge += HPAGE_PMD_NR; } + unlock_page(page); put_page(page); } spin_unlock(ptl); return 0; } - if (pmd_trans_unstable(pmd)) - return 0; retry: pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + if (!pte) + return 0; for (; addr != end; addr += PAGE_SIZE) { - pte_t ptent = *(pte++); + pte_t ptent = ptep_get(pte++); bool device = false; swp_entry_t ent; @@ -6099,7 +6492,7 @@ retry: */ if (PageTransCompound(page)) goto put; - if (!device && isolate_lru_page(page)) + if (!device && !isolate_lru_page(page)) goto put; if (!mem_cgroup_move_account(page, false, mc.from, mc.to)) { @@ -6109,7 +6502,8 @@ retry: } if (!device) putback_lru_page(page); -put: /* get_mctgt_type() gets the page */ +put: /* get_mctgt_type() gets & locks the page */ + unlock_page(page); put_page(page); break; case MC_TARGET_SWAP: @@ -6145,13 +6539,14 @@ put: /* get_mctgt_type() gets the page */ static const struct mm_walk_ops charge_walk_ops = { .pmd_entry = mem_cgroup_move_charge_pte_range, + .walk_lock = PGWALK_RDLOCK, }; static void mem_cgroup_move_charge(void) { lru_add_drain_all(); /* - * Signal lock_page_memcg() to take the memcg's move_lock + * Signal folio_memcg_lock() to take the memcg's move_lock * while we're moving its pages to another memcg. Then wait * for already started RCU-only updates to finish. */ @@ -6174,9 +6569,7 @@ retry: * When we have consumed all precharges and failed in doing * additional charge, the page walk just aborts. */ - walk_page_range(mc.mm, 0, mc.mm->highest_vm_end, &charge_walk_ops, - NULL); - + walk_page_range(mc.mm, 0, ULONG_MAX, &charge_walk_ops, NULL); mmap_read_unlock(mc.mm); atomic_dec(&mc.from->moving_account); } @@ -6188,6 +6581,7 @@ static void mem_cgroup_move_task(void) mem_cgroup_clear_mc(); } } + #else /* !CONFIG_MMU */ static int mem_cgroup_can_attach(struct cgroup_taskset *tset) { @@ -6201,23 +6595,81 @@ static void mem_cgroup_move_task(void) } #endif -/* - * Cgroup retains root cgroups across [un]mount cycles making it necessary - * to verify whether we're attached to the default hierarchy on each mount - * attempt. - */ -static void mem_cgroup_bind(struct cgroup_subsys_state *root_css) +#ifdef CONFIG_MEMCG_KMEM +static void mem_cgroup_fork(struct task_struct *task) { /* - * use_hierarchy is forced on the default hierarchy. cgroup core - * guarantees that @root doesn't have any children, so turning it - * on for the root memcg is enough. + * Set the update flag to cause task->objcg to be initialized lazily + * on the first allocation. It can be done without any synchronization + * because it's always performed on the current task, so does + * current_objcg_update(). */ - if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) - root_mem_cgroup->use_hierarchy = true; - else - root_mem_cgroup->use_hierarchy = false; + task->objcg = (struct obj_cgroup *)CURRENT_OBJCG_UPDATE_FLAG; +} + +static void mem_cgroup_exit(struct task_struct *task) +{ + struct obj_cgroup *objcg = task->objcg; + + objcg = (struct obj_cgroup *) + ((unsigned long)objcg & ~CURRENT_OBJCG_UPDATE_FLAG); + if (objcg) + obj_cgroup_put(objcg); + + /* + * Some kernel allocations can happen after this point, + * but let's ignore them. It can be done without any synchronization + * because it's always performed on the current task, so does + * current_objcg_update(). + */ + task->objcg = NULL; +} +#endif + +#ifdef CONFIG_LRU_GEN +static void mem_cgroup_lru_gen_attach(struct cgroup_taskset *tset) +{ + struct task_struct *task; + struct cgroup_subsys_state *css; + + /* find the first leader if there is any */ + cgroup_taskset_for_each_leader(task, css, tset) + break; + + if (!task) + return; + + task_lock(task); + if (task->mm && READ_ONCE(task->mm->owner) == task) + lru_gen_migrate_mm(task->mm); + task_unlock(task); } +#else +static void mem_cgroup_lru_gen_attach(struct cgroup_taskset *tset) {} +#endif /* CONFIG_LRU_GEN */ + +#ifdef CONFIG_MEMCG_KMEM +static void mem_cgroup_kmem_attach(struct cgroup_taskset *tset) +{ + struct task_struct *task; + struct cgroup_subsys_state *css; + + cgroup_taskset_for_each(task, css, tset) { + /* atomically set the update bit */ + set_bit(CURRENT_OBJCG_UPDATE_BIT, (unsigned long *)&task->objcg); + } +} +#else +static void mem_cgroup_kmem_attach(struct cgroup_taskset *tset) {} +#endif /* CONFIG_MEMCG_KMEM */ + +#if defined(CONFIG_LRU_GEN) || defined(CONFIG_MEMCG_KMEM) +static void mem_cgroup_attach(struct cgroup_taskset *tset) +{ + mem_cgroup_lru_gen_attach(tset); + mem_cgroup_kmem_attach(tset); +} +#endif static int seq_puts_memcg_tunable(struct seq_file *m, unsigned long value) { @@ -6237,6 +6689,14 @@ static u64 memory_current_read(struct cgroup_subsys_state *css, return (u64)page_counter_read(&memcg->memory) * PAGE_SIZE; } +static u64 memory_peak_read(struct cgroup_subsys_state *css, + struct cftype *cft) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + + return (u64)memcg->memory.watermark * PAGE_SIZE; +} + static int memory_min_show(struct seq_file *m, void *v) { return seq_puts_memcg_tunable(m, @@ -6303,6 +6763,8 @@ static ssize_t memory_high_write(struct kernfs_open_file *of, if (err) return err; + page_counter_set_high(&memcg->memory, high); + for (;;) { unsigned long nr_pages = page_counter_read(&memcg->memory); unsigned long reclaimed; @@ -6320,16 +6782,13 @@ static ssize_t memory_high_write(struct kernfs_open_file *of, } reclaimed = try_to_free_mem_cgroup_pages(memcg, nr_pages - high, - GFP_KERNEL, true); + GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP); if (!reclaimed && !nr_retries--) break; } - page_counter_set_high(&memcg->memory, high); - memcg_wb_domain_size_changed(memcg); - return nbytes; } @@ -6372,7 +6831,7 @@ static ssize_t memory_max_write(struct kernfs_open_file *of, if (nr_reclaims) { if (!try_to_free_mem_cgroup_pages(memcg, nr_pages - max, - GFP_KERNEL, true)) + GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP)) nr_reclaims--; continue; } @@ -6386,6 +6845,10 @@ static ssize_t memory_max_write(struct kernfs_open_file *of, return nbytes; } +/* + * Note: don't forget to update the 'samples/cgroup/memcg_event_listener' + * if any new events become available. + */ static void __memory_events_show(struct seq_file *m, atomic_long_t *events) { seq_printf(m, "low %lu\n", atomic_long_read(&events[MEMCG_LOW])); @@ -6394,6 +6857,8 @@ static void __memory_events_show(struct seq_file *m, atomic_long_t *events) seq_printf(m, "oom %lu\n", atomic_long_read(&events[MEMCG_OOM])); seq_printf(m, "oom_kill %lu\n", atomic_long_read(&events[MEMCG_OOM_KILL])); + seq_printf(m, "oom_group_kill %lu\n", + atomic_long_read(&events[MEMCG_OOM_GROUP_KILL])); } static int memory_events_show(struct seq_file *m, void *v) @@ -6415,22 +6880,33 @@ static int memory_events_local_show(struct seq_file *m, void *v) static int memory_stat_show(struct seq_file *m, void *v) { struct mem_cgroup *memcg = mem_cgroup_from_seq(m); - char *buf; + char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL); + struct seq_buf s; - buf = memory_stat_format(memcg); if (!buf) return -ENOMEM; + seq_buf_init(&s, buf, PAGE_SIZE); + memory_stat_format(memcg, &s); seq_puts(m, buf); kfree(buf); return 0; } #ifdef CONFIG_NUMA +static inline unsigned long lruvec_page_state_output(struct lruvec *lruvec, + int item) +{ + return lruvec_page_state(lruvec, item) * + memcg_page_state_output_unit(item); +} + static int memory_numa_stat_show(struct seq_file *m, void *v) { int i; struct mem_cgroup *memcg = mem_cgroup_from_seq(m); + mem_cgroup_flush_stats(memcg); + for (i = 0; i < ARRAY_SIZE(memory_stats); i++) { int nid; @@ -6443,8 +6919,8 @@ static int memory_numa_stat_show(struct seq_file *m, void *v) struct lruvec *lruvec; lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid)); - size = lruvec_page_state(lruvec, memory_stats[i].idx); - size *= memory_stats[i].ratio; + size = lruvec_page_state_output(lruvec, + memory_stats[i].idx); seq_printf(m, " N%d=%llu", nid, size); } seq_putc(m, '\n'); @@ -6458,7 +6934,7 @@ static int memory_oom_group_show(struct seq_file *m, void *v) { struct mem_cgroup *memcg = mem_cgroup_from_seq(m); - seq_printf(m, "%d\n", memcg->oom_group); + seq_printf(m, "%d\n", READ_ONCE(memcg->oom_group)); return 0; } @@ -6480,7 +6956,49 @@ static ssize_t memory_oom_group_write(struct kernfs_open_file *of, if (oom_group != 0 && oom_group != 1) return -EINVAL; - memcg->oom_group = oom_group; + WRITE_ONCE(memcg->oom_group, oom_group); + + return nbytes; +} + +static ssize_t memory_reclaim(struct kernfs_open_file *of, char *buf, + size_t nbytes, loff_t off) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + unsigned int nr_retries = MAX_RECLAIM_RETRIES; + unsigned long nr_to_reclaim, nr_reclaimed = 0; + unsigned int reclaim_options; + int err; + + buf = strstrip(buf); + err = page_counter_memparse(buf, "", &nr_to_reclaim); + if (err) + return err; + + reclaim_options = MEMCG_RECLAIM_MAY_SWAP | MEMCG_RECLAIM_PROACTIVE; + while (nr_reclaimed < nr_to_reclaim) { + unsigned long reclaimed; + + if (signal_pending(current)) + return -EINTR; + + /* + * This is the final attempt, drain percpu lru caches in the + * hope of introducing more evictable pages for + * try_to_free_mem_cgroup_pages(). + */ + if (!nr_retries) + lru_add_drain_all(); + + reclaimed = try_to_free_mem_cgroup_pages(memcg, + min(nr_to_reclaim - nr_reclaimed, SWAP_CLUSTER_MAX), + GFP_KERNEL, reclaim_options); + + if (!reclaimed && !nr_retries--) + return -EAGAIN; + + nr_reclaimed += reclaimed; + } return nbytes; } @@ -6492,6 +7010,11 @@ static struct cftype memory_files[] = { .read_u64 = memory_current_read, }, { + .name = "peak", + .flags = CFTYPE_NOT_ON_ROOT, + .read_u64 = memory_peak_read, + }, + { .name = "min", .flags = CFTYPE_NOT_ON_ROOT, .seq_show = memory_min_show, @@ -6543,6 +7066,11 @@ static struct cftype memory_files[] = { .seq_show = memory_oom_group_show, .write = memory_oom_group_write, }, + { + .name = "reclaim", + .flags = CFTYPE_NS_DELEGATABLE, + .write = memory_reclaim, + }, { } /* terminate */ }; @@ -6553,10 +7081,17 @@ struct cgroup_subsys memory_cgrp_subsys = { .css_released = mem_cgroup_css_released, .css_free = mem_cgroup_css_free, .css_reset = mem_cgroup_css_reset, + .css_rstat_flush = mem_cgroup_css_rstat_flush, .can_attach = mem_cgroup_can_attach, +#if defined(CONFIG_LRU_GEN) || defined(CONFIG_MEMCG_KMEM) + .attach = mem_cgroup_attach, +#endif .cancel_attach = mem_cgroup_cancel_attach, .post_attach = mem_cgroup_move_task, - .bind = mem_cgroup_bind, +#ifdef CONFIG_MEMCG_KMEM + .fork = mem_cgroup_fork, + .exit = mem_cgroup_exit, +#endif .dfl_cftypes = memory_files, .legacy_cftypes = mem_cgroup_legacy_files, .early_init = 0, @@ -6617,7 +7152,7 @@ static unsigned long effective_protection(unsigned long usage, protected = min(usage, setting); /* * If all cgroups at this level combined claim and use more - * protection then what the parent affords them, distribute + * protection than what the parent affords them, distribute * shares in proportion to utilization. * * We are using actual utilization rather than the statically @@ -6679,7 +7214,7 @@ static unsigned long effective_protection(unsigned long usage, } /** - * mem_cgroup_protected - check if memory consumption is in the normal range + * mem_cgroup_calculate_protection - check if memory consumption is in the normal range * @root: the top ancestor of the sub-tree being checked * @memcg: the memory cgroup to check * @@ -6713,9 +7248,6 @@ void mem_cgroup_calculate_protection(struct mem_cgroup *root, return; parent = parent_mem_cgroup(memcg); - /* No parent means a non-hierarchical mode on v1 memcg */ - if (!parent) - return; if (parent == root) { memcg->memory.emin = READ_ONCE(memcg->memory.min); @@ -6736,86 +7268,141 @@ void mem_cgroup_calculate_protection(struct mem_cgroup *root, atomic_long_read(&parent->memory.children_low_usage))); } +static int charge_memcg(struct folio *folio, struct mem_cgroup *memcg, + gfp_t gfp) +{ + int ret; + + ret = try_charge(memcg, gfp, folio_nr_pages(folio)); + if (ret) + goto out; + + mem_cgroup_commit_charge(folio, memcg); +out: + return ret; +} + +int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp) +{ + struct mem_cgroup *memcg; + int ret; + + memcg = get_mem_cgroup_from_mm(mm); + ret = charge_memcg(folio, memcg, gfp); + css_put(&memcg->css); + + return ret; +} + /** - * mem_cgroup_charge - charge a newly allocated page to a cgroup - * @page: page to charge - * @mm: mm context of the victim - * @gfp_mask: reclaim mode + * mem_cgroup_hugetlb_try_charge - try to charge the memcg for a hugetlb folio + * @memcg: memcg to charge. + * @gfp: reclaim mode. + * @nr_pages: number of pages to charge. * - * Try to charge @page to the memcg that @mm belongs to, reclaiming - * pages according to @gfp_mask if necessary. + * This function is called when allocating a huge page folio to determine if + * the memcg has the capacity for it. It does not commit the charge yet, + * as the hugetlb folio itself has not been obtained from the hugetlb pool. + * + * Once we have obtained the hugetlb folio, we can call + * mem_cgroup_commit_charge() to commit the charge. If we fail to obtain the + * folio, we should instead call mem_cgroup_cancel_charge() to undo the effect + * of try_charge(). * * Returns 0 on success. Otherwise, an error code is returned. */ -int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) +int mem_cgroup_hugetlb_try_charge(struct mem_cgroup *memcg, gfp_t gfp, + long nr_pages) { - unsigned int nr_pages = thp_nr_pages(page); - struct mem_cgroup *memcg = NULL; - int ret = 0; + /* + * If hugetlb memcg charging is not enabled, do not fail hugetlb allocation, + * but do not attempt to commit charge later (or cancel on error) either. + */ + if (mem_cgroup_disabled() || !memcg || + !cgroup_subsys_on_dfl(memory_cgrp_subsys) || + !(cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING)) + return -EOPNOTSUPP; - if (mem_cgroup_disabled()) - goto out; + if (try_charge(memcg, gfp, nr_pages)) + return -ENOMEM; - if (PageSwapCache(page)) { - swp_entry_t ent = { .val = page_private(page), }; - unsigned short id; + return 0; +} - /* - * Every swap fault against a single page tries to charge the - * page, bail as early as possible. shmem_unuse() encounters - * already charged pages, too. page->mem_cgroup is protected - * by the page lock, which serializes swap cache removal, which - * in turn serializes uncharging. - */ - VM_BUG_ON_PAGE(!PageLocked(page), page); - if (compound_head(page)->mem_cgroup) - goto out; +/** + * mem_cgroup_swapin_charge_folio - Charge a newly allocated folio for swapin. + * @folio: folio to charge. + * @mm: mm context of the victim + * @gfp: reclaim mode + * @entry: swap entry for which the folio is allocated + * + * This function charges a folio allocated for swapin. Please call this before + * adding the folio to the swapcache. + * + * Returns 0 on success. Otherwise, an error code is returned. + */ +int mem_cgroup_swapin_charge_folio(struct folio *folio, struct mm_struct *mm, + gfp_t gfp, swp_entry_t entry) +{ + struct mem_cgroup *memcg; + unsigned short id; + int ret; - id = lookup_swap_cgroup_id(ent); - rcu_read_lock(); - memcg = mem_cgroup_from_id(id); - if (memcg && !css_tryget_online(&memcg->css)) - memcg = NULL; - rcu_read_unlock(); - } + if (mem_cgroup_disabled()) + return 0; - if (!memcg) + id = lookup_swap_cgroup_id(entry); + rcu_read_lock(); + memcg = mem_cgroup_from_id(id); + if (!memcg || !css_tryget_online(&memcg->css)) memcg = get_mem_cgroup_from_mm(mm); + rcu_read_unlock(); - ret = try_charge(memcg, gfp_mask, nr_pages); - if (ret) - goto out_put; + ret = charge_memcg(folio, memcg, gfp); - css_get(&memcg->css); - commit_charge(page, memcg); - - local_irq_disable(); - mem_cgroup_charge_statistics(memcg, page, nr_pages); - memcg_check_events(memcg, page); - local_irq_enable(); + css_put(&memcg->css); + return ret; +} - if (PageSwapCache(page)) { - swp_entry_t entry = { .val = page_private(page) }; +/* + * mem_cgroup_swapin_uncharge_swap - uncharge swap slot + * @entry: swap entry for which the page is charged + * + * Call this function after successfully adding the charged page to swapcache. + * + * Note: This function assumes the page for which swap slot is being uncharged + * is order 0 page. + */ +void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry) +{ + /* + * Cgroup1's unified memory+swap counter has been charged with the + * new swapcache page, finish the transfer by uncharging the swap + * slot. The swap slot would also get uncharged when it dies, but + * it can stick around indefinitely and we'd count the page twice + * the entire time. + * + * Cgroup2 has separate resource counters for memory and swap, + * so this is a non-issue here. Memory and swap charge lifetimes + * correspond 1:1 to page and swap slot lifetimes: we charge the + * page to memory here, and uncharge swap when the slot is freed. + */ + if (!mem_cgroup_disabled() && do_memsw_account()) { /* * The swap entry might not get freed for a long time, * let's not wait for it. The page already received a * memory+swap charge, drop the swap entry duplicate. */ - mem_cgroup_uncharge_swap(entry, nr_pages); + mem_cgroup_uncharge_swap(entry, 1); } - -out_put: - css_put(&memcg->css); -out: - return ret; } struct uncharge_gather { struct mem_cgroup *memcg; - unsigned long nr_pages; + unsigned long nr_memory; unsigned long pgpgout; unsigned long nr_kmem; - struct page *dummy_page; + int nid; }; static inline void uncharge_gather_clear(struct uncharge_gather *ug) @@ -6827,179 +7414,215 @@ static void uncharge_batch(const struct uncharge_gather *ug) { unsigned long flags; - if (!mem_cgroup_is_root(ug->memcg)) { - page_counter_uncharge(&ug->memcg->memory, ug->nr_pages); + if (ug->nr_memory) { + page_counter_uncharge(&ug->memcg->memory, ug->nr_memory); if (do_memsw_account()) - page_counter_uncharge(&ug->memcg->memsw, ug->nr_pages); - if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && ug->nr_kmem) - page_counter_uncharge(&ug->memcg->kmem, ug->nr_kmem); + page_counter_uncharge(&ug->memcg->memsw, ug->nr_memory); + if (ug->nr_kmem) + memcg_account_kmem(ug->memcg, -ug->nr_kmem); memcg_oom_recover(ug->memcg); } local_irq_save(flags); __count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout); - __this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, ug->nr_pages); - memcg_check_events(ug->memcg, ug->dummy_page); + __this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, ug->nr_memory); + memcg_check_events(ug->memcg, ug->nid); local_irq_restore(flags); - /* drop reference from uncharge_page */ + /* drop reference from uncharge_folio */ css_put(&ug->memcg->css); } -static void uncharge_page(struct page *page, struct uncharge_gather *ug) +static void uncharge_folio(struct folio *folio, struct uncharge_gather *ug) { - unsigned long nr_pages; - - VM_BUG_ON_PAGE(PageLRU(page), page); + long nr_pages; + struct mem_cgroup *memcg; + struct obj_cgroup *objcg; - if (!page->mem_cgroup) - return; + VM_BUG_ON_FOLIO(folio_test_lru(folio), folio); /* * Nobody should be changing or seriously looking at - * page->mem_cgroup at this point, we have fully - * exclusive access to the page. + * folio memcg or objcg at this point, we have fully + * exclusive access to the folio. */ + if (folio_memcg_kmem(folio)) { + objcg = __folio_objcg(folio); + /* + * This get matches the put at the end of the function and + * kmem pages do not hold memcg references anymore. + */ + memcg = get_mem_cgroup_from_objcg(objcg); + } else { + memcg = __folio_memcg(folio); + } - if (ug->memcg != page->mem_cgroup) { + if (!memcg) + return; + + if (ug->memcg != memcg) { if (ug->memcg) { uncharge_batch(ug); uncharge_gather_clear(ug); } - ug->memcg = page->mem_cgroup; + ug->memcg = memcg; + ug->nid = folio_nid(folio); /* pairs with css_put in uncharge_batch */ - css_get(&ug->memcg->css); + css_get(&memcg->css); } - nr_pages = compound_nr(page); - ug->nr_pages += nr_pages; + nr_pages = folio_nr_pages(folio); - if (!PageKmemcg(page)) { - ug->pgpgout++; - } else { + if (folio_memcg_kmem(folio)) { + ug->nr_memory += nr_pages; ug->nr_kmem += nr_pages; - __ClearPageKmemcg(page); - } - ug->dummy_page = page; - page->mem_cgroup = NULL; - css_put(&ug->memcg->css); -} - -static void uncharge_list(struct list_head *page_list) -{ - struct uncharge_gather ug; - struct list_head *next; - - uncharge_gather_clear(&ug); - - /* - * Note that the list can be a single page->lru; hence the - * do-while loop instead of a simple list_for_each_entry(). - */ - next = page_list->next; - do { - struct page *page; - - page = list_entry(next, struct page, lru); - next = page->lru.next; + folio->memcg_data = 0; + obj_cgroup_put(objcg); + } else { + /* LRU pages aren't accounted at the root level */ + if (!mem_cgroup_is_root(memcg)) + ug->nr_memory += nr_pages; + ug->pgpgout++; - uncharge_page(page, &ug); - } while (next != page_list); + folio->memcg_data = 0; + } - if (ug.memcg) - uncharge_batch(&ug); + css_put(&memcg->css); } -/** - * mem_cgroup_uncharge - uncharge a page - * @page: page to uncharge - * - * Uncharge a page previously charged with mem_cgroup_charge(). - */ -void mem_cgroup_uncharge(struct page *page) +void __mem_cgroup_uncharge(struct folio *folio) { struct uncharge_gather ug; - if (mem_cgroup_disabled()) - return; - - /* Don't touch page->lru of any random page, pre-check: */ - if (!page->mem_cgroup) + /* Don't touch folio->lru of any random page, pre-check: */ + if (!folio_memcg(folio)) return; uncharge_gather_clear(&ug); - uncharge_page(page, &ug); + uncharge_folio(folio, &ug); uncharge_batch(&ug); } /** - * mem_cgroup_uncharge_list - uncharge a list of page + * __mem_cgroup_uncharge_list - uncharge a list of page * @page_list: list of pages to uncharge * * Uncharge a list of pages previously charged with - * mem_cgroup_charge(). + * __mem_cgroup_charge(). */ -void mem_cgroup_uncharge_list(struct list_head *page_list) +void __mem_cgroup_uncharge_list(struct list_head *page_list) { - if (mem_cgroup_disabled()) - return; + struct uncharge_gather ug; + struct folio *folio; - if (!list_empty(page_list)) - uncharge_list(page_list); + uncharge_gather_clear(&ug); + list_for_each_entry(folio, page_list, lru) + uncharge_folio(folio, &ug); + if (ug.memcg) + uncharge_batch(&ug); } /** - * mem_cgroup_migrate - charge a page's replacement - * @oldpage: currently circulating page - * @newpage: replacement page + * mem_cgroup_replace_folio - Charge a folio's replacement. + * @old: Currently circulating folio. + * @new: Replacement folio. * - * Charge @newpage as a replacement page for @oldpage. @oldpage will - * be uncharged upon free. + * Charge @new as a replacement folio for @old. @old will + * be uncharged upon free. This is only used by the page cache + * (in replace_page_cache_folio()). * - * Both pages must be locked, @newpage->mapping must be set up. + * Both folios must be locked, @new->mapping must be set up. */ -void mem_cgroup_migrate(struct page *oldpage, struct page *newpage) +void mem_cgroup_replace_folio(struct folio *old, struct folio *new) { struct mem_cgroup *memcg; - unsigned int nr_pages; + long nr_pages = folio_nr_pages(new); unsigned long flags; - VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage); - VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); - VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage); - VM_BUG_ON_PAGE(PageTransHuge(oldpage) != PageTransHuge(newpage), - newpage); + VM_BUG_ON_FOLIO(!folio_test_locked(old), old); + VM_BUG_ON_FOLIO(!folio_test_locked(new), new); + VM_BUG_ON_FOLIO(folio_test_anon(old) != folio_test_anon(new), new); + VM_BUG_ON_FOLIO(folio_nr_pages(old) != nr_pages, new); if (mem_cgroup_disabled()) return; - /* Page cache replacement: new page already charged? */ - if (newpage->mem_cgroup) + /* Page cache replacement: new folio already charged? */ + if (folio_memcg(new)) return; - /* Swapcache readahead pages can get replaced before being charged */ - memcg = oldpage->mem_cgroup; + memcg = folio_memcg(old); + VM_WARN_ON_ONCE_FOLIO(!memcg, old); if (!memcg) return; /* Force-charge the new page. The old one will be freed soon */ - nr_pages = thp_nr_pages(newpage); - - page_counter_charge(&memcg->memory, nr_pages); - if (do_memsw_account()) - page_counter_charge(&memcg->memsw, nr_pages); + if (!mem_cgroup_is_root(memcg)) { + page_counter_charge(&memcg->memory, nr_pages); + if (do_memsw_account()) + page_counter_charge(&memcg->memsw, nr_pages); + } css_get(&memcg->css); - commit_charge(newpage, memcg); + commit_charge(new, memcg); local_irq_save(flags); - mem_cgroup_charge_statistics(memcg, newpage, nr_pages); - memcg_check_events(memcg, newpage); + mem_cgroup_charge_statistics(memcg, nr_pages); + memcg_check_events(memcg, folio_nid(new)); local_irq_restore(flags); } +/** + * mem_cgroup_migrate - Transfer the memcg data from the old to the new folio. + * @old: Currently circulating folio. + * @new: Replacement folio. + * + * Transfer the memcg data from the old folio to the new folio for migration. + * The old folio's data info will be cleared. Note that the memory counters + * will remain unchanged throughout the process. + * + * Both folios must be locked, @new->mapping must be set up. + */ +void mem_cgroup_migrate(struct folio *old, struct folio *new) +{ + struct mem_cgroup *memcg; + + VM_BUG_ON_FOLIO(!folio_test_locked(old), old); + VM_BUG_ON_FOLIO(!folio_test_locked(new), new); + VM_BUG_ON_FOLIO(folio_test_anon(old) != folio_test_anon(new), new); + VM_BUG_ON_FOLIO(folio_nr_pages(old) != folio_nr_pages(new), new); + + if (mem_cgroup_disabled()) + return; + + memcg = folio_memcg(old); + /* + * Note that it is normal to see !memcg for a hugetlb folio. + * For e.g, itt could have been allocated when memory_hugetlb_accounting + * was not selected. + */ + VM_WARN_ON_ONCE_FOLIO(!folio_test_hugetlb(old) && !memcg, old); + if (!memcg) + return; + + /* Transfer the charge and the css ref */ + commit_charge(new, memcg); + /* + * If the old folio is a large folio and is in the split queue, it needs + * to be removed from the split queue now, in case getting an incorrect + * split queue in destroy_large_folio() after the memcg of the old folio + * is cleared. + * + * In addition, the old folio is about to be freed after migration, so + * removing from the split queue a bit earlier seems reasonable. + */ + if (folio_test_large(old) && folio_test_large_rmappable(old)) + folio_undo_large_rmappable(old); + old->memcg_data = 0; +} + DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key); EXPORT_SYMBOL(memcg_sockets_enabled_key); @@ -7011,12 +7634,12 @@ void mem_cgroup_sk_alloc(struct sock *sk) return; /* Do not associate the sock with unrelated interrupted task's memcg. */ - if (in_interrupt()) + if (!in_task()) return; rcu_read_lock(); memcg = mem_cgroup_from_task(current); - if (memcg == root_mem_cgroup) + if (mem_cgroup_is_root(memcg)) goto out; if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg->tcpmem_active) goto out; @@ -7036,14 +7659,14 @@ void mem_cgroup_sk_free(struct sock *sk) * mem_cgroup_charge_skmem - charge socket memory * @memcg: memcg to charge * @nr_pages: number of pages to charge + * @gfp_mask: reclaim mode * * Charges @nr_pages to @memcg. Returns %true if the charge fit within - * @memcg's configured limit, %false if the charge had to be forced. + * @memcg's configured limit, %false if it doesn't. */ -bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages) +bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages, + gfp_t gfp_mask) { - gfp_t gfp_mask = GFP_KERNEL; - if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) { struct page_counter *fail; @@ -7051,21 +7674,19 @@ bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages) memcg->tcpmem_pressure = 0; return true; } - page_counter_charge(&memcg->tcpmem, nr_pages); memcg->tcpmem_pressure = 1; + if (gfp_mask & __GFP_NOFAIL) { + page_counter_charge(&memcg->tcpmem, nr_pages); + return true; + } return false; } - /* Don't block in the packet receive path */ - if (in_softirq()) - gfp_mask = GFP_NOWAIT; - - mod_memcg_state(memcg, MEMCG_SOCK, nr_pages); - - if (try_charge(memcg, gfp_mask, nr_pages) == 0) + if (try_charge(memcg, gfp_mask, nr_pages) == 0) { + mod_memcg_state(memcg, MEMCG_SOCK, nr_pages); return true; + } - try_charge(memcg, gfp_mask|__GFP_NOFAIL, nr_pages); return false; } @@ -7097,8 +7718,10 @@ static int __init cgroup_memory(char *s) cgroup_memory_nosocket = true; if (!strcmp(token, "nokmem")) cgroup_memory_nokmem = true; + if (!strcmp(token, "nobpf")) + cgroup_memory_nobpf = true; } - return 0; + return 1; } __setup("cgroup.memory=", cgroup_memory); @@ -7114,6 +7737,14 @@ static int __init mem_cgroup_init(void) { int cpu, node; + /* + * Currently s32 type (can refer to struct batched_lruvec_stat) is + * used for per-memcg-per-cpu caching of per-node statistics. In order + * to work fine, we should make sure that the overfill threshold can't + * exceed S32_MAX / PAGE_SIZE. + */ + BUILD_BUG_ON(MEMCG_CHARGE_BATCH > S32_MAX / PAGE_SIZE); + cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL, memcg_hotplug_cpu_dead); @@ -7124,8 +7755,7 @@ static int __init mem_cgroup_init(void) for_each_node(node) { struct mem_cgroup_tree_per_node *rtpn; - rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, - node_online(node) ? node : NUMA_NO_NODE); + rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, node); rtpn->rb_root = RB_ROOT; rtpn->rb_rightmost = NULL; @@ -7137,7 +7767,7 @@ static int __init mem_cgroup_init(void) } subsys_initcall(mem_cgroup_init); -#ifdef CONFIG_MEMCG_SWAP +#ifdef CONFIG_SWAP static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg) { while (!refcount_inc_not_zero(&memcg->id.ref)) { @@ -7145,7 +7775,7 @@ static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg) * The root cgroup cannot be destroyed, so it's refcount must * always be >= 1. */ - if (WARN_ON_ONCE(memcg == root_mem_cgroup)) { + if (WARN_ON_ONCE(mem_cgroup_is_root(memcg))) { VM_BUG_ON(1); break; } @@ -7158,26 +7788,29 @@ static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg) /** * mem_cgroup_swapout - transfer a memsw charge to swap - * @page: page whose memsw charge to transfer + * @folio: folio whose memsw charge to transfer * @entry: swap entry to move the charge to * - * Transfer the memsw charge of @page to @entry. + * Transfer the memsw charge of @folio to @entry. */ -void mem_cgroup_swapout(struct page *page, swp_entry_t entry) +void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry) { struct mem_cgroup *memcg, *swap_memcg; unsigned int nr_entries; unsigned short oldid; - VM_BUG_ON_PAGE(PageLRU(page), page); - VM_BUG_ON_PAGE(page_count(page), page); + VM_BUG_ON_FOLIO(folio_test_lru(folio), folio); + VM_BUG_ON_FOLIO(folio_ref_count(folio), folio); - if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) + if (mem_cgroup_disabled()) return; - memcg = page->mem_cgroup; + if (!do_memsw_account()) + return; + + memcg = folio_memcg(folio); - /* Readahead page, never charged */ + VM_WARN_ON_ONCE_FOLIO(!memcg, folio); if (!memcg) return; @@ -7187,21 +7820,21 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry) * ancestor for the swap instead and transfer the memory+swap charge. */ swap_memcg = mem_cgroup_id_get_online(memcg); - nr_entries = thp_nr_pages(page); + nr_entries = folio_nr_pages(folio); /* Get references for the tail pages, too */ if (nr_entries > 1) mem_cgroup_id_get_many(swap_memcg, nr_entries - 1); oldid = swap_cgroup_record(entry, mem_cgroup_id(swap_memcg), nr_entries); - VM_BUG_ON_PAGE(oldid, page); + VM_BUG_ON_FOLIO(oldid, folio); mod_memcg_state(swap_memcg, MEMCG_SWAP, nr_entries); - page->mem_cgroup = NULL; + folio->memcg_data = 0; if (!mem_cgroup_is_root(memcg)) page_counter_uncharge(&memcg->memory, nr_entries); - if (!cgroup_memory_noswap && memcg != swap_memcg) { + if (memcg != swap_memcg) { if (!mem_cgroup_is_root(swap_memcg)) page_counter_charge(&swap_memcg->memsw, nr_entries); page_counter_uncharge(&memcg->memsw, nr_entries); @@ -7213,35 +7846,36 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry) * important here to have the interrupts disabled because it is the * only synchronisation we have for updating the per-CPU variables. */ - VM_BUG_ON(!irqs_disabled()); - mem_cgroup_charge_statistics(memcg, page, -nr_entries); - memcg_check_events(memcg, page); + memcg_stats_lock(); + mem_cgroup_charge_statistics(memcg, -nr_entries); + memcg_stats_unlock(); + memcg_check_events(memcg, folio_nid(folio)); css_put(&memcg->css); } /** - * mem_cgroup_try_charge_swap - try charging swap space for a page - * @page: page being added to swap + * __mem_cgroup_try_charge_swap - try charging swap space for a folio + * @folio: folio being added to swap * @entry: swap entry to charge * - * Try to charge @page's memcg for the swap space at @entry. + * Try to charge @folio's memcg for the swap space at @entry. * * Returns 0 on success, -ENOMEM on failure. */ -int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry) +int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry) { - unsigned int nr_pages = thp_nr_pages(page); + unsigned int nr_pages = folio_nr_pages(folio); struct page_counter *counter; struct mem_cgroup *memcg; unsigned short oldid; - if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) + if (do_memsw_account()) return 0; - memcg = page->mem_cgroup; + memcg = folio_memcg(folio); - /* Readahead page, never charged */ + VM_WARN_ON_ONCE_FOLIO(!memcg, folio); if (!memcg) return 0; @@ -7252,7 +7886,7 @@ int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry) memcg = mem_cgroup_id_get_online(memcg); - if (!cgroup_memory_noswap && !mem_cgroup_is_root(memcg) && + if (!mem_cgroup_is_root(memcg) && !page_counter_try_charge(&memcg->swap, nr_pages, &counter)) { memcg_memory_event(memcg, MEMCG_SWAP_MAX); memcg_memory_event(memcg, MEMCG_SWAP_FAIL); @@ -7264,18 +7898,18 @@ int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry) if (nr_pages > 1) mem_cgroup_id_get_many(memcg, nr_pages - 1); oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg), nr_pages); - VM_BUG_ON_PAGE(oldid, page); + VM_BUG_ON_FOLIO(oldid, folio); mod_memcg_state(memcg, MEMCG_SWAP, nr_pages); return 0; } /** - * mem_cgroup_uncharge_swap - uncharge swap space + * __mem_cgroup_uncharge_swap - uncharge swap space * @entry: swap entry to uncharge * @nr_pages: the amount of swap space to uncharge */ -void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages) +void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages) { struct mem_cgroup *memcg; unsigned short id; @@ -7284,11 +7918,11 @@ void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages) rcu_read_lock(); memcg = mem_cgroup_from_id(id); if (memcg) { - if (!cgroup_memory_noswap && !mem_cgroup_is_root(memcg)) { - if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) - page_counter_uncharge(&memcg->swap, nr_pages); - else + if (!mem_cgroup_is_root(memcg)) { + if (do_memsw_account()) page_counter_uncharge(&memcg->memsw, nr_pages); + else + page_counter_uncharge(&memcg->swap, nr_pages); } mod_memcg_state(memcg, MEMCG_SWAP, -nr_pages); mem_cgroup_id_put_many(memcg, nr_pages); @@ -7300,31 +7934,31 @@ long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) { long nr_swap_pages = get_nr_swap_pages(); - if (cgroup_memory_noswap || !cgroup_subsys_on_dfl(memory_cgrp_subsys)) + if (mem_cgroup_disabled() || do_memsw_account()) return nr_swap_pages; - for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) + for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) nr_swap_pages = min_t(long, nr_swap_pages, READ_ONCE(memcg->swap.max) - page_counter_read(&memcg->swap)); return nr_swap_pages; } -bool mem_cgroup_swap_full(struct page *page) +bool mem_cgroup_swap_full(struct folio *folio) { struct mem_cgroup *memcg; - VM_BUG_ON_PAGE(!PageLocked(page), page); + VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); if (vm_swap_full()) return true; - if (cgroup_memory_noswap || !cgroup_subsys_on_dfl(memory_cgrp_subsys)) + if (do_memsw_account()) return false; - memcg = page->mem_cgroup; + memcg = folio_memcg(folio); if (!memcg) return false; - for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) { + for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) { unsigned long usage = page_counter_read(&memcg->swap); if (usage * 2 >= READ_ONCE(memcg->swap.high) || @@ -7337,10 +7971,13 @@ bool mem_cgroup_swap_full(struct page *page) static int __init setup_swap_account(char *s) { - if (!strcmp(s, "1")) - cgroup_memory_noswap = 0; - else if (!strcmp(s, "0")) - cgroup_memory_noswap = 1; + bool res; + + if (!kstrtobool(s, &res) && !res) + pr_warn_once("The swapaccount=0 commandline option is deprecated " + "in favor of configuring swap control via cgroupfs. " + "Please report your usecase to linux-mm@kvack.org if you " + "depend on this functionality.\n"); return 1; } __setup("swapaccount=", setup_swap_account); @@ -7353,6 +7990,14 @@ static u64 swap_current_read(struct cgroup_subsys_state *css, return (u64)page_counter_read(&memcg->swap) * PAGE_SIZE; } +static u64 swap_peak_read(struct cgroup_subsys_state *css, + struct cftype *cft) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + + return (u64)memcg->swap.watermark * PAGE_SIZE; +} + static int swap_high_show(struct seq_file *m, void *v) { return seq_puts_memcg_tunable(m, @@ -7432,6 +8077,11 @@ static struct cftype swap_files[] = { .write = swap_max_write, }, { + .name = "swap.peak", + .flags = CFTYPE_NOT_ON_ROOT, + .read_u64 = swap_peak_read, + }, + { .name = "swap.events", .flags = CFTYPE_NOT_ON_ROOT, .file_offset = offsetof(struct mem_cgroup, swap_events_file), @@ -7467,27 +8117,202 @@ static struct cftype memsw_files[] = { { }, /* terminate */ }; -/* - * If mem_cgroup_swap_init() is implemented as a subsys_initcall() - * instead of a core_initcall(), this could mean cgroup_memory_noswap still - * remains set to false even when memcg is disabled via "cgroup_disable=memory" - * boot parameter. This may result in premature OOPS inside - * mem_cgroup_get_nr_swap_pages() function in corner cases. +#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP) +/** + * obj_cgroup_may_zswap - check if this cgroup can zswap + * @objcg: the object cgroup + * + * Check if the hierarchical zswap limit has been reached. + * + * This doesn't check for specific headroom, and it is not atomic + * either. But with zswap, the size of the allocation is only known + * once compression has occurred, and this optimistic pre-check avoids + * spending cycles on compression when there is already no room left + * or zswap is disabled altogether somewhere in the hierarchy. */ +bool obj_cgroup_may_zswap(struct obj_cgroup *objcg) +{ + struct mem_cgroup *memcg, *original_memcg; + bool ret = true; + + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) + return true; + + original_memcg = get_mem_cgroup_from_objcg(objcg); + for (memcg = original_memcg; !mem_cgroup_is_root(memcg); + memcg = parent_mem_cgroup(memcg)) { + unsigned long max = READ_ONCE(memcg->zswap_max); + unsigned long pages; + + if (max == PAGE_COUNTER_MAX) + continue; + if (max == 0) { + ret = false; + break; + } + + /* + * mem_cgroup_flush_stats() ignores small changes. Use + * do_flush_stats() directly to get accurate stats for charging. + */ + do_flush_stats(memcg); + pages = memcg_page_state(memcg, MEMCG_ZSWAP_B) / PAGE_SIZE; + if (pages < max) + continue; + ret = false; + break; + } + mem_cgroup_put(original_memcg); + return ret; +} + +/** + * obj_cgroup_charge_zswap - charge compression backend memory + * @objcg: the object cgroup + * @size: size of compressed object + * + * This forces the charge after obj_cgroup_may_zswap() allowed + * compression and storage in zwap for this cgroup to go ahead. + */ +void obj_cgroup_charge_zswap(struct obj_cgroup *objcg, size_t size) +{ + struct mem_cgroup *memcg; + + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) + return; + + VM_WARN_ON_ONCE(!(current->flags & PF_MEMALLOC)); + + /* PF_MEMALLOC context, charging must succeed */ + if (obj_cgroup_charge(objcg, GFP_KERNEL, size)) + VM_WARN_ON_ONCE(1); + + rcu_read_lock(); + memcg = obj_cgroup_memcg(objcg); + mod_memcg_state(memcg, MEMCG_ZSWAP_B, size); + mod_memcg_state(memcg, MEMCG_ZSWAPPED, 1); + rcu_read_unlock(); +} + +/** + * obj_cgroup_uncharge_zswap - uncharge compression backend memory + * @objcg: the object cgroup + * @size: size of compressed object + * + * Uncharges zswap memory on page in. + */ +void obj_cgroup_uncharge_zswap(struct obj_cgroup *objcg, size_t size) +{ + struct mem_cgroup *memcg; + + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) + return; + + obj_cgroup_uncharge(objcg, size); + + rcu_read_lock(); + memcg = obj_cgroup_memcg(objcg); + mod_memcg_state(memcg, MEMCG_ZSWAP_B, -size); + mod_memcg_state(memcg, MEMCG_ZSWAPPED, -1); + rcu_read_unlock(); +} + +bool mem_cgroup_zswap_writeback_enabled(struct mem_cgroup *memcg) +{ + /* if zswap is disabled, do not block pages going to the swapping device */ + return !is_zswap_enabled() || !memcg || READ_ONCE(memcg->zswap_writeback); +} + +static u64 zswap_current_read(struct cgroup_subsys_state *css, + struct cftype *cft) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + + mem_cgroup_flush_stats(memcg); + return memcg_page_state(memcg, MEMCG_ZSWAP_B); +} + +static int zswap_max_show(struct seq_file *m, void *v) +{ + return seq_puts_memcg_tunable(m, + READ_ONCE(mem_cgroup_from_seq(m)->zswap_max)); +} + +static ssize_t zswap_max_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + unsigned long max; + int err; + + buf = strstrip(buf); + err = page_counter_memparse(buf, "max", &max); + if (err) + return err; + + xchg(&memcg->zswap_max, max); + + return nbytes; +} + +static int zswap_writeback_show(struct seq_file *m, void *v) +{ + struct mem_cgroup *memcg = mem_cgroup_from_seq(m); + + seq_printf(m, "%d\n", READ_ONCE(memcg->zswap_writeback)); + return 0; +} + +static ssize_t zswap_writeback_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + int zswap_writeback; + ssize_t parse_ret = kstrtoint(strstrip(buf), 0, &zswap_writeback); + + if (parse_ret) + return parse_ret; + + if (zswap_writeback != 0 && zswap_writeback != 1) + return -EINVAL; + + WRITE_ONCE(memcg->zswap_writeback, zswap_writeback); + return nbytes; +} + +static struct cftype zswap_files[] = { + { + .name = "zswap.current", + .flags = CFTYPE_NOT_ON_ROOT, + .read_u64 = zswap_current_read, + }, + { + .name = "zswap.max", + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = zswap_max_show, + .write = zswap_max_write, + }, + { + .name = "zswap.writeback", + .seq_show = zswap_writeback_show, + .write = zswap_writeback_write, + }, + { } /* terminate */ +}; +#endif /* CONFIG_MEMCG_KMEM && CONFIG_ZSWAP */ + static int __init mem_cgroup_swap_init(void) { - /* No memory control -> no swap control */ if (mem_cgroup_disabled()) - cgroup_memory_noswap = true; - - if (cgroup_memory_noswap) return 0; WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, swap_files)); WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, memsw_files)); - +#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP) + WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, zswap_files)); +#endif return 0; } -core_initcall(mem_cgroup_swap_init); +subsys_initcall(mem_cgroup_swap_init); -#endif /* CONFIG_MEMCG_SWAP */ +#endif /* CONFIG_SWAP */ |