| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Johannes Weiner | 5320 | 27.27% | 119 | 17.27% |
| Roman Gushchin | 3526 | 18.07% | 73 | 10.60% |
| Shakeel Butt | 1612 | 8.26% | 32 | 4.64% |
| Vladimir Davydov | 1246 | 6.39% | 26 | 3.77% |
| Song Muchun | 734 | 3.76% | 22 | 3.19% |
| Yosry Ahmed | 665 | 3.41% | 21 | 3.05% |
| Kamezawa Hiroyuki | 576 | 2.95% | 40 | 5.81% |
| Waiman Long | 421 | 2.16% | 6 | 0.87% |
| Vlastimil Babka | 407 | 2.09% | 4 | 0.58% |
| Tejun Heo | 401 | 2.06% | 32 | 4.64% |
| Nhat Pham | 372 | 1.91% | 4 | 0.58% |
| Chris Down | 325 | 1.67% | 17 | 2.47% |
| Matthew Wilcox | 319 | 1.63% | 20 | 2.90% |
| Michal Hocko | 313 | 1.60% | 32 | 4.64% |
| Jakub Kiciński | 262 | 1.34% | 5 | 0.73% |
| Sebastian Andrzej Siewior | 255 | 1.31% | 5 | 0.73% |
| Dan Schatzberg | 250 | 1.28% | 4 | 0.58% |
| Glauber de Oliveira Costa | 210 | 1.08% | 12 | 1.74% |
| Kirill V Tkhai | 189 | 0.97% | 5 | 0.73% |
| Andrew Morton | 162 | 0.83% | 8 | 1.16% |
| Alex Shi | 140 | 0.72% | 3 | 0.44% |
| Yu Zhao | 106 | 0.54% | 4 | 0.58% |
| Huang Ying | 103 | 0.53% | 3 | 0.44% |
| Yafang Shao | 102 | 0.52% | 4 | 0.58% |
| Jérôme Glisse | 100 | 0.51% | 1 | 0.15% |
| Balbir Singh | 94 | 0.48% | 13 | 1.89% |
| Hugh Dickins | 88 | 0.45% | 9 | 1.31% |
| Breno Leitão | 87 | 0.45% | 2 | 0.29% |
| Tetsuo Handa | 60 | 0.31% | 3 | 0.44% |
| Miles Chen | 58 | 0.30% | 1 | 0.15% |
| Daisuke Nishimura | 57 | 0.29% | 7 | 1.02% |
| Arnd Bergmann | 53 | 0.27% | 1 | 0.15% |
| Anton Vorontsov | 46 | 0.24% | 1 | 0.15% |
| Raghavendra K T | 45 | 0.23% | 1 | 0.15% |
| Kamalesh Babulal | 40 | 0.21% | 1 | 0.15% |
| Yang Shi | 40 | 0.21% | 4 | 0.58% |
| Sha Zhengju | 39 | 0.20% | 1 | 0.15% |
| Qi Zheng | 37 | 0.19% | 1 | 0.15% |
| Lars R. Damerow | 30 | 0.15% | 1 | 0.15% |
| Wei Yang | 28 | 0.14% | 4 | 0.58% |
| Vasily Averin | 27 | 0.14% | 4 | 0.58% |
| Yue Zhao | 24 | 0.12% | 4 | 0.58% |
| Tahsin Erdogan | 23 | 0.12% | 1 | 0.15% |
| Ganesan Rajagopal | 22 | 0.11% | 1 | 0.15% |
| Mel Gorman | 22 | 0.11% | 4 | 0.58% |
| Suren Baghdasaryan | 21 | 0.11% | 3 | 0.44% |
| Pavel Emelyanov | 19 | 0.10% | 1 | 0.15% |
| Mike Yuan | 19 | 0.10% | 1 | 0.15% |
| T.J. Mercier | 18 | 0.09% | 2 | 0.29% |
| Linus Torvalds (pre-git) | 18 | 0.09% | 8 | 1.16% |
| Konstantin Khlebnikov | 15 | 0.08% | 3 | 0.44% |
| Naoya Horiguchi | 15 | 0.08% | 2 | 0.29% |
| Li Zefan | 14 | 0.07% | 3 | 0.44% |
| Suleiman Souhlal | 14 | 0.07% | 1 | 0.15% |
| JoonSoo Kim | 13 | 0.07% | 1 | 0.15% |
| Christoph Lameter | 13 | 0.07% | 4 | 0.58% |
| Xiu Jianfeng | 13 | 0.07% | 2 | 0.29% |
| Motohiro Kosaki | 12 | 0.06% | 3 | 0.44% |
| Ying Han | 12 | 0.06% | 3 | 0.44% |
| David Rientjes | 12 | 0.06% | 4 | 0.58% |
| Seth Jennings | 12 | 0.06% | 2 | 0.29% |
| Wei Wang | 12 | 0.06% | 1 | 0.15% |
| Baolin Wang | 11 | 0.06% | 2 | 0.29% |
| Kirill A. Shutemov | 9 | 0.05% | 4 | 0.58% |
| Kefeng Wang | 8 | 0.04% | 3 | 0.44% |
| Ingo Molnar | 8 | 0.04% | 3 | 0.44% |
| Wang Weiyang | 8 | 0.04% | 1 | 0.15% |
| Florian Schmidt | 7 | 0.04% | 1 | 0.15% |
| Domenico Cerasuolo | 7 | 0.04% | 2 | 0.29% |
| Greg Thelen | 7 | 0.04% | 1 | 0.15% |
| Sean Christopherson | 6 | 0.03% | 1 | 0.15% |
| Al Viro | 6 | 0.03% | 1 | 0.15% |
| Dan Carpenter | 6 | 0.03% | 2 | 0.29% |
| Baoquan He | 6 | 0.03% | 1 | 0.15% |
| Lai Jiangshan | 6 | 0.03% | 1 | 0.15% |
| Miaohe Lin | 5 | 0.03% | 5 | 0.73% |
| Mina Almasry | 5 | 0.03% | 1 | 0.15% |
| Oleg Nesterov | 5 | 0.03% | 1 | 0.15% |
| Li RongQing | 5 | 0.03% | 1 | 0.15% |
| Jiebin Sun | 5 | 0.03% | 1 | 0.15% |
| yuzhoujian | 5 | 0.03% | 1 | 0.15% |
| Pekka J Enberg | 5 | 0.03% | 1 | 0.15% |
| Thomas Gleixner | 5 | 0.03% | 2 | 0.29% |
| Maarten Lankhorst | 5 | 0.03% | 1 | 0.15% |
| Jason Low | 4 | 0.02% | 1 | 0.15% |
| Michal Koutný | 4 | 0.02% | 1 | 0.15% |
| Zi Yan | 4 | 0.02% | 1 | 0.15% |
| Vern Hao | 4 | 0.02% | 1 | 0.15% |
| Hirokazu Takahashi | 4 | 0.02% | 1 | 0.15% |
| Paul Gortmaker | 3 | 0.02% | 1 | 0.15% |
| Aristeu Sergio Rozanski Filho | 3 | 0.02% | 1 | 0.15% |
| Dan J Williams | 3 | 0.02% | 1 | 0.15% |
| Nicholas Piggin | 3 | 0.02% | 1 | 0.15% |
| David Chinner | 3 | 0.02% | 1 | 0.15% |
| Steven Rostedt | 3 | 0.02% | 1 | 0.15% |
| Jesper Dangaard Brouer | 3 | 0.02% | 1 | 0.15% |
| Alexey Dobriyan | 3 | 0.02% | 1 | 0.15% |
| Qiang Huang | 3 | 0.02% | 1 | 0.15% |
| Jianyu Zhan | 3 | 0.02% | 1 | 0.15% |
| ZhangPeng | 2 | 0.01% | 1 | 0.15% |
| Randy Dunlap | 2 | 0.01% | 2 | 0.29% |
| Muhammad Muzammil | 2 | 0.01% | 1 | 0.15% |
| Gerald Schaefer | 2 | 0.01% | 1 | 0.15% |
| Linus Torvalds | 2 | 0.01% | 2 | 0.29% |
| Wanpeng Li | 2 | 0.01% | 2 | 0.29% |
| Dhaval Giani | 2 | 0.01% | 1 | 0.15% |
| Hui Su | 2 | 0.01% | 1 | 0.15% |
| Kairui Song | 2 | 0.01% | 1 | 0.15% |
| Xia Kaixu | 1 | 0.01% | 1 | 0.15% |
| Eric W. Biedermann | 1 | 0.01% | 1 | 0.15% |
| Christoph Hellwig | 1 | 0.01% | 1 | 0.15% |
| xupanda | 1 | 0.01% | 1 | 0.15% |
| Vincenzo Frascino | 1 | 0.01% | 1 | 0.15% |
| Ethon Paul | 1 | 0.01% | 1 | 0.15% |
| Matthias Kaehlcke | 1 | 0.01% | 1 | 0.15% |
| Xiang Yang | 1 | 0.01% | 1 | 0.15% |
| Lee Schermerhorn | 1 | 0.01% | 1 | 0.15% |
| Srivatsa Vaddagiri | 1 | 0.01% | 1 | 0.15% |
| Mike Rapoport | 1 | 0.01% | 1 | 0.15% |
| Dmitry Rokosov | 1 | 0.01% | 1 | 0.15% |
| Zhou Guanghui | 1 | 0.01% | 1 | 0.15% |
| Efly Young | 1 | 0.01% | 1 | 0.15% |
| Andrea Arcangeli | 1 | 0.01% | 1 | 0.15% |
| Total | 19511 | 689 |
// SPDX-License-Identifier: GPL-2.0-or-later /* memcontrol.c - Memory Controller * * Copyright IBM Corporation, 2007 * Author Balbir Singh <balbir@linux.vnet.ibm.com> * * Copyright 2007 OpenVZ SWsoft Inc * Author: Pavel Emelianov <xemul@openvz.org> * * Memory thresholds * Copyright (C) 2009 Nokia Corporation * Author: Kirill A. Shutemov * * Kernel Memory Controller * Copyright (C) 2012 Parallels Inc. and Google Inc. * Authors: Glauber Costa and Suleiman Souhlal * * Native page reclaim * Charge lifetime sanitation * 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> #include <linux/memcontrol.h> #include <linux/cgroup.h> #include <linux/sched/mm.h> #include <linux/shmem_fs.h> #include <linux/hugetlb.h> #include <linux/pagemap.h> #include <linux/pagevec.h> #include <linux/vm_event_item.h> #include <linux/smp.h> #include <linux/page-flags.h> #include <linux/backing-dev.h> #include <linux/bit_spinlock.h> #include <linux/rcupdate.h> #include <linux/limits.h> #include <linux/export.h> #include <linux/mutex.h> #include <linux/rbtree.h> #include <linux/slab.h> #include <linux/swapops.h> #include <linux/spinlock.h> #include <linux/fs.h> #include <linux/seq_file.h> #include <linux/parser.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/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 "memcontrol-v1.h" #include <linux/uaccess.h> #include <trace/events/vmscan.h> struct cgroup_subsys memory_cgrp_subsys __read_mostly; EXPORT_SYMBOL(memory_cgrp_subsys); 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 __ro_after_init; /* Kernel memory accounting disabled? */ static bool cgroup_memory_nokmem __ro_after_init; /* 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); #endif #define THRESHOLDS_EVENTS_TARGET 128 #define SOFTLIMIT_EVENTS_TARGET 1024 static inline bool task_is_dying(void) { return tsk_is_oom_victim(current) || fatal_signal_pending(current) || (current->flags & PF_EXITING); } /* Some nice accessors for the vmpressure. */ struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg) { if (!memcg) memcg = root_mem_cgroup; return &memcg->vmpressure; } struct mem_cgroup *vmpressure_to_memcg(struct vmpressure *vmpr) { return container_of(vmpr, struct mem_cgroup, vmpressure); } #define CURRENT_OBJCG_UPDATE_BIT 0 #define CURRENT_OBJCG_UPDATE_FLAG (1UL << CURRENT_OBJCG_UPDATE_BIT) 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); unsigned int nr_bytes; unsigned int nr_pages; unsigned long flags; /* * At this point all allocated objects are freed, and * objcg->nr_charged_bytes can't have an arbitrary byte value. * However, it can be PAGE_SIZE or (x * PAGE_SIZE). * * The following sequence can lead to it: * 1) CPU0: objcg == stock->cached_objcg * 2) CPU1: we do a small allocation (e.g. 92 bytes), * PAGE_SIZE bytes are charged * 3) CPU1: a process from another memcg is allocating something, * the stock if flushed, * objcg->nr_charged_bytes = PAGE_SIZE - 92 * 5) CPU0: we do release this object, * 92 bytes are added to stock->nr_bytes * 6) CPU0: stock is flushed, * 92 bytes are added to objcg->nr_charged_bytes * * In the result, nr_charged_bytes == PAGE_SIZE. * This page will be uncharged in obj_cgroup_release(). */ nr_bytes = atomic_read(&objcg->nr_charged_bytes); WARN_ON_ONCE(nr_bytes & (PAGE_SIZE - 1)); nr_pages = nr_bytes >> PAGE_SHIFT; if (nr_pages) obj_cgroup_uncharge_pages(objcg, nr_pages); spin_lock_irqsave(&objcg_lock, flags); list_del(&objcg->list); spin_unlock_irqrestore(&objcg_lock, flags); percpu_ref_exit(ref); kfree_rcu(objcg, rcu); } static struct obj_cgroup *obj_cgroup_alloc(void) { struct obj_cgroup *objcg; int ret; objcg = kzalloc(sizeof(struct obj_cgroup), GFP_KERNEL); if (!objcg) return NULL; ret = percpu_ref_init(&objcg->refcnt, obj_cgroup_release, 0, GFP_KERNEL); if (ret) { kfree(objcg); return NULL; } INIT_LIST_HEAD(&objcg->list); return objcg; } static void memcg_reparent_objcgs(struct mem_cgroup *memcg, struct mem_cgroup *parent) { struct obj_cgroup *objcg, *iter; objcg = rcu_replace_pointer(memcg->objcg, NULL, true); spin_lock_irq(&objcg_lock); /* 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(&objcg_lock); percpu_ref_kill(&objcg->refcnt); } /* * A lot of the calls to the cache allocation functions are expected to be * inlined by the compiler. Since the calls to memcg_slab_post_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_online_key); EXPORT_SYMBOL(memcg_kmem_online_key); DEFINE_STATIC_KEY_FALSE(memcg_bpf_enabled_key); EXPORT_SYMBOL(memcg_bpf_enabled_key); /** * 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 @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_folio(struct folio *folio) { struct mem_cgroup *memcg = folio_memcg(folio); if (!memcg || !cgroup_subsys_on_dfl(memory_cgrp_subsys)) memcg = root_mem_cgroup; return &memcg->css; } /** * page_cgroup_ino - return inode number of the memcg a page is charged to * @page: the page * * Look up the closest online ancestor of the memory cgroup @page is charged to * and return its inode number or 0 if @page is not charged to any cgroup. It * is safe to call this function without holding a reference to @page. * * Note, this function is inherently racy, because there is nothing to prevent * the cgroup inode from getting torn down and potentially reallocated a moment * after page_cgroup_ino() returns, so it only should be used by callers that * do not care (such as procfs interfaces). */ ino_t page_cgroup_ino(struct page *page) { struct mem_cgroup *memcg; unsigned long ino = 0; rcu_read_lock(); /* 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); if (memcg) ino = cgroup_ino(memcg->css.cgroup); rcu_read_unlock(); return ino; } /* Subset of node_stat_item for memcg stats */ static const unsigned int memcg_node_stat_items[] = { NR_INACTIVE_ANON, NR_ACTIVE_ANON, NR_INACTIVE_FILE, NR_ACTIVE_FILE, NR_UNEVICTABLE, NR_SLAB_RECLAIMABLE_B, NR_SLAB_UNRECLAIMABLE_B, WORKINGSET_REFAULT_ANON, WORKINGSET_REFAULT_FILE, WORKINGSET_ACTIVATE_ANON, WORKINGSET_ACTIVATE_FILE, WORKINGSET_RESTORE_ANON, WORKINGSET_RESTORE_FILE, WORKINGSET_NODERECLAIM, NR_ANON_MAPPED, NR_FILE_MAPPED, NR_FILE_PAGES, NR_FILE_DIRTY, NR_WRITEBACK, NR_SHMEM, NR_SHMEM_THPS, NR_FILE_THPS, NR_ANON_THPS, NR_KERNEL_STACK_KB, NR_PAGETABLE, NR_SECONDARY_PAGETABLE, #ifdef CONFIG_SWAP NR_SWAPCACHE, #endif }; static const unsigned int memcg_stat_items[] = { MEMCG_SWAP, MEMCG_SOCK, MEMCG_PERCPU_B, MEMCG_VMALLOC, MEMCG_KMEM, MEMCG_ZSWAP_B, MEMCG_ZSWAPPED, }; #define NR_MEMCG_NODE_STAT_ITEMS ARRAY_SIZE(memcg_node_stat_items) #define MEMCG_VMSTAT_SIZE (NR_MEMCG_NODE_STAT_ITEMS + \ ARRAY_SIZE(memcg_stat_items)) static int8_t mem_cgroup_stats_index[MEMCG_NR_STAT] __read_mostly; static void init_memcg_stats(void) { int8_t i, j = 0; BUILD_BUG_ON(MEMCG_NR_STAT >= S8_MAX); for (i = 0; i < NR_MEMCG_NODE_STAT_ITEMS; ++i) mem_cgroup_stats_index[memcg_node_stat_items[i]] = ++j; for (i = 0; i < ARRAY_SIZE(memcg_stat_items); ++i) mem_cgroup_stats_index[memcg_stat_items[i]] = ++j; } static inline int memcg_stats_index(int idx) { return mem_cgroup_stats_index[idx] - 1; } struct lruvec_stats_percpu { /* Local (CPU and cgroup) state */ long state[NR_MEMCG_NODE_STAT_ITEMS]; /* Delta calculation for lockless upward propagation */ long state_prev[NR_MEMCG_NODE_STAT_ITEMS]; }; struct lruvec_stats { /* Aggregated (CPU and subtree) state */ long state[NR_MEMCG_NODE_STAT_ITEMS]; /* Non-hierarchical (CPU aggregated) state */ long state_local[NR_MEMCG_NODE_STAT_ITEMS]; /* Pending child counts during tree propagation */ long state_pending[NR_MEMCG_NODE_STAT_ITEMS]; }; unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx) { struct mem_cgroup_per_node *pn; long x; int i; if (mem_cgroup_disabled()) return node_page_state(lruvec_pgdat(lruvec), idx); i = memcg_stats_index(idx); if (WARN_ONCE(i < 0, "%s: missing stat item %d\n", __func__, idx)) return 0; pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec); x = READ_ONCE(pn->lruvec_stats->state[i]); #ifdef CONFIG_SMP if (x < 0) x = 0; #endif return x; } unsigned long lruvec_page_state_local(struct lruvec *lruvec, enum node_stat_item idx) { struct mem_cgroup_per_node *pn; long x; int i; if (mem_cgroup_disabled()) return node_page_state(lruvec_pgdat(lruvec), idx); i = memcg_stats_index(idx); if (WARN_ONCE(i < 0, "%s: missing stat item %d\n", __func__, idx)) return 0; pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec); x = READ_ONCE(pn->lruvec_stats->state_local[i]); #ifdef CONFIG_SMP if (x < 0) x = 0; #endif return x; } /* 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, #ifdef 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 int8_t mem_cgroup_events_index[NR_VM_EVENT_ITEMS] __read_mostly; static void init_memcg_events(void) { int8_t i; BUILD_BUG_ON(NR_VM_EVENT_ITEMS >= S8_MAX); 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_VMSTAT_SIZE]; unsigned long events[NR_MEMCG_EVENTS]; /* Delta calculation for lockless upward propagation */ long state_prev[MEMCG_VMSTAT_SIZE]; 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_VMSTAT_SIZE]; unsigned long events[NR_MEMCG_EVENTS]; /* Non-hierarchical (CPU aggregated) page state & events */ long state_local[MEMCG_VMSTAT_SIZE]; unsigned long events_local[NR_MEMCG_EVENTS]; /* Pending child counts during tree propagation */ long state_pending[MEMCG_VMSTAT_SIZE]; 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(); unsigned int stats_updates; if (!val) return; cgroup_rstat_updated(memcg->css.cgroup, cpu); statc = this_cpu_ptr(memcg->vmstats_percpu); for (; statc; statc = statc->parent) { stats_updates = READ_ONCE(statc->stats_updates) + abs(val); WRITE_ONCE(statc->stats_updates, stats_updates); if (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(stats_updates, &statc->vmstats->stats_updates); WRITE_ONCE(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; int i = memcg_stats_index(idx); if (WARN_ONCE(i < 0, "%s: missing stat item %d\n", __func__, idx)) return 0; x = READ_ONCE(memcg->vmstats->state[i]); #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 * @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item * @val: delta to add to the counter, can be negative */ void __mod_memcg_state(struct mem_cgroup *memcg, enum memcg_stat_item idx, int val) { int i = memcg_stats_index(idx); if (mem_cgroup_disabled()) return; if (WARN_ONCE(i < 0, "%s: missing stat item %d\n", __func__, idx)) return; __this_cpu_add(memcg->vmstats_percpu->state[i], val); memcg_rstat_updated(memcg, memcg_state_val_in_pages(idx, val)); } /* idx can be of type enum memcg_stat_item or node_stat_item. */ unsigned long memcg_page_state_local(struct mem_cgroup *memcg, int idx) { long x; int i = memcg_stats_index(idx); if (WARN_ONCE(i < 0, "%s: missing stat item %d\n", __func__, idx)) return 0; x = READ_ONCE(memcg->vmstats->state_local[i]); #ifdef CONFIG_SMP if (x < 0) x = 0; #endif return x; } static void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx, int val) { struct mem_cgroup_per_node *pn; struct mem_cgroup *memcg; int i = memcg_stats_index(idx); if (WARN_ONCE(i < 0, "%s: missing stat item %d\n", __func__, idx)) return; 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: WARN_ON_ONCE(!in_task()); break; default: VM_WARN_ON_IRQS_ENABLED(); } } /* Update memcg */ __this_cpu_add(memcg->vmstats_percpu->state[i], val); /* Update lruvec */ __this_cpu_add(pn->lruvec_stats_percpu->state[i], val); memcg_rstat_updated(memcg, memcg_state_val_in_pages(idx, val)); memcg_stats_unlock(); } /** * __mod_lruvec_state - update lruvec memory statistics * @lruvec: the lruvec * @idx: the stat item * @val: delta to add to the counter, can be negative * * The lruvec is the intersection of the NUMA node and a cgroup. This * function updates the all three counters that are affected by a * change of state at this level: per-node, per-cgroup, per-lruvec. */ void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx, int val) { /* Update node */ __mod_node_page_state(lruvec_pgdat(lruvec), idx, val); /* Update memcg and lruvec */ if (!mem_cgroup_disabled()) __mod_memcg_lruvec_state(lruvec, idx, val); } void __lruvec_stat_mod_folio(struct folio *folio, enum node_stat_item idx, int val) { struct mem_cgroup *memcg; pg_data_t *pgdat = folio_pgdat(folio); struct lruvec *lruvec; rcu_read_lock(); memcg = folio_memcg(folio); /* Untracked pages have no memcg, no lruvec. Update only the node */ if (!memcg) { rcu_read_unlock(); __mod_node_page_state(pgdat, 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_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_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(); } /** * __count_memcg_events - account VM events in a cgroup * @memcg: the memory cgroup * @idx: the event item * @count: the number of events that occurred */ void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx, unsigned long count) { int i = memcg_events_index(idx); if (mem_cgroup_disabled()) return; if (WARN_ONCE(i < 0, "%s: missing stat item %d\n", __func__, idx)) return; memcg_stats_lock(); __this_cpu_add(memcg->vmstats_percpu->events[i], count); memcg_rstat_updated(memcg, count); memcg_stats_unlock(); } unsigned long memcg_events(struct mem_cgroup *memcg, int event) { int i = memcg_events_index(event); if (WARN_ONCE(i < 0, "%s: missing stat item %d\n", __func__, event)) return 0; return READ_ONCE(memcg->vmstats->events[i]); } unsigned long memcg_events_local(struct mem_cgroup *memcg, int event) { int i = memcg_events_index(event); if (WARN_ONCE(i < 0, "%s: missing stat item %d\n", __func__, event)) return 0; return READ_ONCE(memcg->vmstats->events_local[i]); } void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, int nr_pages) { /* pagein of a big page is an event. So, ignore page size */ if (nr_pages > 0) __count_memcg_events(memcg, PGPGIN, 1); else { __count_memcg_events(memcg, PGPGOUT, 1); nr_pages = -nr_pages; /* for event */ } __this_cpu_add(memcg->vmstats_percpu->nr_page_events, nr_pages); } bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, enum mem_cgroup_events_target target) { unsigned long val, next; val = __this_cpu_read(memcg->vmstats_percpu->nr_page_events); next = __this_cpu_read(memcg->vmstats_percpu->targets[target]); /* from time_after() in jiffies.h */ if ((long)(next - val) < 0) { switch (target) { case MEM_CGROUP_TARGET_THRESH: next = val + THRESHOLDS_EVENTS_TARGET; break; case MEM_CGROUP_TARGET_SOFTLIMIT: next = val + SOFTLIMIT_EVENTS_TARGET; break; default: break; } __this_cpu_write(memcg->vmstats_percpu->targets[target], next); return true; } return false; } struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) { /* * mm_update_next_owner() may clear mm->owner to NULL * if it races with swapoff, page migration, etc. * So this can be called with p == NULL. */ if (unlikely(!p)) return NULL; return mem_cgroup_from_css(task_css(p, memory_cgrp_id)); } 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. 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) { struct mem_cgroup *memcg; 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 { 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; } EXPORT_SYMBOL(get_mem_cgroup_from_mm); /** * get_mem_cgroup_from_current - Obtain a reference on current task's memcg. */ struct mem_cgroup *get_mem_cgroup_from_current(void) { struct mem_cgroup *memcg; if (mem_cgroup_disabled()) return NULL; again: rcu_read_lock(); memcg = mem_cgroup_from_task(current); if (!css_tryget(&memcg->css)) { rcu_read_unlock(); goto again; } rcu_read_unlock(); return memcg; } /** * mem_cgroup_iter - iterate over memory cgroup hierarchy * @root: hierarchy root * @prev: previously returned memcg, NULL on first invocation * @reclaim: cookie for shared reclaim walks, NULL for full walks * * Returns references to children of the hierarchy below @root, or * @root itself, or %NULL after a full round-trip. * * Caller must pass the return value in @prev on subsequent * invocations for reference counting, or use mem_cgroup_iter_break() * to cancel a hierarchy walk before the round-trip is complete. * * Reclaimers can specify a node in @reclaim to divide up the memcgs * in the hierarchy among all concurrent reclaimers operating on the * same node. */ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, struct mem_cgroup *prev, struct mem_cgroup_reclaim_cookie *reclaim) { struct mem_cgroup_reclaim_iter *iter; struct cgroup_subsys_state *css = NULL; struct mem_cgroup *memcg = NULL; struct mem_cgroup *pos = NULL; if (mem_cgroup_disabled()) return NULL; if (!root) root = root_mem_cgroup; rcu_read_lock(); if (reclaim) { struct mem_cgroup_per_node *mz; mz = root->nodeinfo[reclaim->pgdat->node_id]; iter = &mz->iter; /* * 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) { pos = READ_ONCE(iter->position); if (!pos || css_tryget(&pos->css)) break; /* * css reference reached zero, so iter->position will * be cleared by ->css_released. However, we should not * rely on this happening soon, because ->css_released * is called from a work queue, and by busy-waiting we * might block it. So we clear iter->position right * away. */ (void)cmpxchg(&iter->position, pos, NULL); } } else if (prev) { pos = prev; } if (pos) css = &pos->css; for (;;) { css = css_next_descendant_pre(css, &root->css); if (!css) { /* * Reclaimers share the hierarchy walk, and a * new one might jump in right at the end of * the hierarchy - make sure they see at least * one group and restart from the beginning. */ if (!prev) continue; break; } /* * Verify the css and acquire a reference. The root * is provided by the caller, so we know it's alive * and kicking, and don't take an extra reference. */ if (css == &root->css || css_tryget(css)) { memcg = mem_cgroup_from_css(css); break; } } if (reclaim) { /* * The position could have already been updated by a competing * thread, so check that the value hasn't changed since we read * it to avoid reclaiming from the same cgroup twice. */ (void)cmpxchg(&iter->position, pos, memcg); if (pos) css_put(&pos->css); if (!memcg) iter->generation++; } out_unlock: rcu_read_unlock(); if (prev && prev != root) css_put(&prev->css); return memcg; } /** * mem_cgroup_iter_break - abort a hierarchy walk prematurely * @root: hierarchy root * @prev: last visited hierarchy member as returned by mem_cgroup_iter() */ void mem_cgroup_iter_break(struct mem_cgroup *root, struct mem_cgroup *prev) { if (!root) root = root_mem_cgroup; if (prev && prev != root) css_put(&prev->css); } static void __invalidate_reclaim_iterators(struct mem_cgroup *from, struct mem_cgroup *dead_memcg) { struct mem_cgroup_reclaim_iter *iter; struct mem_cgroup_per_node *mz; int nid; for_each_node(nid) { mz = from->nodeinfo[nid]; iter = &mz->iter; cmpxchg(&iter->position, dead_memcg, NULL); } } static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg) { struct mem_cgroup *memcg = dead_memcg; struct mem_cgroup *last; do { __invalidate_reclaim_iterators(memcg, dead_memcg); last = memcg; } while ((memcg = parent_mem_cgroup(memcg))); /* * 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 (!mem_cgroup_is_root(last)) __invalidate_reclaim_iterators(root_mem_cgroup, dead_memcg); } /** * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy * @memcg: hierarchy root * @fn: function to call for each task * @arg: argument passed to @fn * * 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. Otherwise, it will iterate * over all tasks and return 0. * * This function must not be called for the root memory cgroup. */ 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(mem_cgroup_is_root(memcg)); for_each_mem_cgroup_tree(iter, memcg) { struct css_task_iter it; struct task_struct *task; css_task_iter_start(&iter->css, CSS_TASK_ITER_PROCS, &it); while (!ret && (task = css_task_iter_next(&it))) ret = fn(task, arg); css_task_iter_end(&it); if (ret) { mem_cgroup_iter_break(memcg, iter); break; } } } #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 /** * 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) * * Return: The lruvec this folio is on with its lock held. */ struct lruvec *folio_lruvec_lock(struct folio *folio) { struct lruvec *lruvec = folio_lruvec(folio); spin_lock(&lruvec->lru_lock); lruvec_memcg_debug(lruvec, folio); 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); return lruvec; } /** * mem_cgroup_update_lru_size - account for adding or removing an lru page * @lruvec: mem_cgroup per zone lru vector * @lru: index of lru list the page is sitting on * @zid: zone id of the accounted pages * @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. */ void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru, int zid, int nr_pages) { struct mem_cgroup_per_node *mz; unsigned long *lru_size; long size; if (mem_cgroup_disabled()) return; mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec); lru_size = &mz->lru_zone_size[zid][lru]; if (nr_pages < 0) *lru_size += nr_pages; size = *lru_size; if (WARN_ONCE(size < 0, "%s(%p, %d, %d): lru_size %ld\n", __func__, lruvec, lru, nr_pages, size)) { VM_BUG_ON(1); *lru_size = 0; } if (nr_pages > 0) *lru_size += nr_pages; } /** * mem_cgroup_margin - calculate chargeable space of a memory cgroup * @memcg: the memory cgroup * * Returns the maximum amount of memory @mem can be charged with, in * pages. */ static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg) { unsigned long margin = 0; unsigned long count; unsigned long limit; count = page_counter_read(&memcg->memory); limit = READ_ONCE(memcg->memory.max); if (count < limit) margin = limit - count; if (do_memsw_account()) { count = page_counter_read(&memcg->memsw); limit = READ_ONCE(memcg->memsw.max); if (count < limit) margin = min(margin, limit - count); else margin = 0; } return margin; } struct memory_stat { const char *name; unsigned int idx; }; 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 }, #ifdef 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 { "anon_thp", NR_ANON_THPS }, { "file_thp", NR_FILE_THPS }, { "shmem_thp", NR_SHMEM_THPS }, #endif { "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", 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 }, }; /* The actual unit of the state item, not the same as the output unit */ static int memcg_page_state_unit(int item) { 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; } } /* 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); } } unsigned long memcg_page_state_output(struct mem_cgroup *memcg, int item) { return memcg_page_state(memcg, item) * memcg_page_state_output_unit(item); } unsigned long memcg_page_state_local_output(struct mem_cgroup *memcg, int item) { return memcg_page_state_local(memcg, item) * memcg_page_state_output_unit(item); } 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 * well as cumulative event counters that show past behavior. * * This list is ordered following a combination of these gradients: * 1) generic big picture -> specifics and details * 2) reflecting userspace activity -> reflecting kernel heuristics * * Current memory state: */ mem_cgroup_flush_stats(memcg); for (i = 0; i < ARRAY_SIZE(memory_stats); i++) { u64 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_output(memcg, NR_SLAB_RECLAIMABLE_B); seq_buf_printf(s, "slab %llu\n", size); } } /* Accumulated memory events */ seq_buf_printf(s, "pgscan %lu\n", memcg_events(memcg, PGSCAN_KSWAPD) + 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) + memcg_events(memcg, PGSTEAL_KHUGEPAGED)); 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])); } } 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); if (seq_buf_has_overflowed(s)) pr_warn("%s: Warning, stat buffer overflow, please report\n", __func__); } /** * mem_cgroup_print_oom_context: Print OOM information relevant to * memory controller. * @memcg: The memory cgroup that went over limit * @p: Task that is going to be killed * * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is * enabled */ void mem_cgroup_print_oom_context(struct mem_cgroup *memcg, struct task_struct *p) { rcu_read_lock(); if (memcg) { pr_cont(",oom_memcg="); pr_cont_cgroup_path(memcg->css.cgroup); } else pr_cont(",global_oom"); if (p) { pr_cont(",task_memcg="); pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id)); } rcu_read_unlock(); } /** * mem_cgroup_print_oom_meminfo: Print OOM memory information relevant to * memory controller. * @memcg: The memory cgroup that went over limit */ void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg) { /* 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)), K((u64)READ_ONCE(memcg->memory.max)), memcg->memory.failcnt); if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) pr_info("swap: usage %llukB, limit %llukB, failcnt %lu\n", K((u64)page_counter_read(&memcg->swap)), K((u64)READ_ONCE(memcg->swap.max)), memcg->swap.failcnt); #ifdef CONFIG_MEMCG_V1 else { pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n", K((u64)page_counter_read(&memcg->memsw)), K((u64)memcg->memsw.max), memcg->memsw.failcnt); pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n", K((u64)page_counter_read(&memcg->kmem)), K((u64)memcg->kmem.max), memcg->kmem.failcnt); } #endif pr_info("Memory cgroup stats for "); pr_cont_cgroup_path(memcg->css.cgroup); pr_cont(":"); seq_buf_init(&s, buf, sizeof(buf)); memory_stat_format(memcg, &s); seq_buf_do_printk(&s, KERN_INFO); } /* * Return the memory (and swap, if configured) limit for a memcg. */ unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg) { unsigned long max = READ_ONCE(memcg->memory.max); 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; } unsigned long mem_cgroup_size(struct mem_cgroup *memcg) { return page_counter_read(&memcg->memory); } static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, int order) { struct oom_control oc = { .zonelist = NULL, .nodemask = NULL, .memcg = memcg, .gfp_mask = gfp_mask, .order = order, }; bool ret = true; if (mutex_lock_killable(&oom_lock)) return true; if (mem_cgroup_margin(memcg) >= (1 << order)) goto unlock; /* * A few threads which were not waiting at mutex_lock_killable() can * fail to bail out. Therefore, check again after holding oom_lock. */ ret = task_is_dying() || out_of_memory(&oc); unlock: mutex_unlock(&oom_lock); return ret; } /* * 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) { bool locked, ret; if (order > PAGE_ALLOC_COSTLY_ORDER) return false; memcg_memory_event(memcg, MEMCG_OOM); if (!memcg1_oom_prepare(memcg, &locked)) return false; ret = mem_cgroup_out_of_memory(memcg, mask, order); memcg1_oom_finish(memcg, locked); return ret; } /** * mem_cgroup_get_oom_group - get a memory cgroup to clean up after OOM * @victim: task to be killed by the OOM killer * @oom_domain: memcg in case of memcg OOM, NULL in case of system-wide OOM * * Returns a pointer to a memory cgroup, which has to be cleaned up * by killing all belonging OOM-killable tasks. * * Caller has to call mem_cgroup_put() on the returned non-NULL memcg. */ struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim, struct mem_cgroup *oom_domain) { struct mem_cgroup *oom_group = NULL; struct mem_cgroup *memcg; if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) return NULL; if (!oom_domain) oom_domain = root_mem_cgroup; rcu_read_lock(); memcg = mem_cgroup_from_task(victim); if (mem_cgroup_is_root(memcg)) goto out; /* * If the victim task has been asynchronously moved to a different * memory cgroup, we might end up killing tasks outside oom_domain. * In this case it's better to ignore memory.group.oom. */ if (unlikely(!mem_cgroup_is_descendant(memcg, oom_domain))) goto out; /* * Traverse the memory cgroup hierarchy from the victim task's * cgroup up to the OOMing cgroup (or root) to find the * highest-level memory cgroup with oom.group set. */ for (; memcg; memcg = parent_mem_cgroup(memcg)) { if (READ_ONCE(memcg->oom_group)) oom_group = memcg; if (memcg == oom_domain) break; } if (oom_group) css_get(&oom_group->css); out: rcu_read_unlock(); return oom_group; } void mem_cgroup_print_oom_group(struct mem_cgroup *memcg) { pr_info("Tasks in "); pr_cont_cgroup_path(memcg->css.cgroup); pr_cont(" are going to be killed due to memory.oom.group set\n"); } struct memcg_stock_pcp { local_lock_t stock_lock; struct mem_cgroup *cached; /* this never be root cgroup */ unsigned int nr_pages; struct obj_cgroup *cached_objcg; struct pglist_data *cached_pgdat; unsigned int nr_bytes; int nr_slab_reclaimable_b; int nr_slab_unreclaimable_b; struct work_struct work; unsigned long flags; #define FLUSHING_CACHED_CHARGE 0 }; static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock) = { .stock_lock = INIT_LOCAL_LOCK(stock_lock), }; static DEFINE_MUTEX(percpu_charge_mutex); 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); /** * consume_stock: Try to consume stocked charge on this cpu. * @memcg: memcg to consume from. * @nr_pages: how many pages to charge. * * The charges will only happen if @memcg matches the current cpu's memcg * stock, and at least @nr_pages are available in that stock. Failure to * service an allocation will refill the stock. * * returns true if successful, false otherwise. */ static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages) { struct memcg_stock_pcp *stock; unsigned int stock_pages; unsigned long flags; bool ret = false; if (nr_pages > MEMCG_CHARGE_BATCH) return ret; local_lock_irqsave(&memcg_stock.stock_lock, flags); stock = this_cpu_ptr(&memcg_stock); stock_pages = READ_ONCE(stock->nr_pages); if (memcg == READ_ONCE(stock->cached) && stock_pages >= nr_pages) { WRITE_ONCE(stock->nr_pages, stock_pages - nr_pages); ret = true; } local_unlock_irqrestore(&memcg_stock.stock_lock, flags); return ret; } /* * Returns stocks cached in percpu and reset cached information. */ static void drain_stock(struct memcg_stock_pcp *stock) { unsigned int stock_pages = READ_ONCE(stock->nr_pages); struct mem_cgroup *old = READ_ONCE(stock->cached); if (!old) return; if (stock_pages) { page_counter_uncharge(&old->memory, stock_pages); if (do_memsw_account()) page_counter_uncharge(&old->memsw, stock_pages); WRITE_ONCE(stock->nr_pages, 0); } css_put(&old->css); 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 cpu hotplug (memcg_hotplug_cpu_dead) vs. * drain_stock races is that we always operate on local CPU stock * here with IRQ disabled */ local_lock_irqsave(&memcg_stock.stock_lock, flags); stock = this_cpu_ptr(&memcg_stock); old = drain_obj_stock(stock); drain_stock(stock); clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); local_unlock_irqrestore(&memcg_stock.stock_lock, flags); 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) { struct memcg_stock_pcp *stock; unsigned int stock_pages; stock = this_cpu_ptr(&memcg_stock); if (READ_ONCE(stock->cached) != memcg) { /* reset if necessary */ drain_stock(stock); css_get(&memcg->css); WRITE_ONCE(stock->cached, memcg); } stock_pages = READ_ONCE(stock->nr_pages) + nr_pages; WRITE_ONCE(stock->nr_pages, stock_pages); if (stock_pages > MEMCG_CHARGE_BATCH) drain_stock(stock); } 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); } /* * Drains all per-CPU charge caches for given root_memcg resp. subtree * of the hierarchy under it. */ void drain_all_stock(struct mem_cgroup *root_memcg) { int cpu, curcpu; /* If someone's already draining, avoid adding running more workers. */ if (!mutex_trylock(&percpu_charge_mutex)) return; /* * Notify other cpus that system-wide "drain" is running * We do not care about races with the cpu hotplug because cpu down * as well as workers from this path always operate on the local * per-cpu data. CPU up doesn't touch memcg_stock at all. */ 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 = READ_ONCE(stock->cached); if (memcg && READ_ONCE(stock->nr_pages) && mem_cgroup_is_descendant(memcg, root_memcg)) flush = true; else if (obj_stock_flush_required(stock, root_memcg)) flush = true; rcu_read_unlock(); if (flush && !test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) { if (cpu == curcpu) drain_local_stock(&stock->work); else if (!cpu_is_isolated(cpu)) schedule_work_on(cpu, &stock->work); } } migrate_enable(); mutex_unlock(&percpu_charge_mutex); } static int memcg_hotplug_cpu_dead(unsigned int cpu) { struct memcg_stock_pcp *stock; stock = &per_cpu(memcg_stock, cpu); drain_stock(stock); return 0; } static unsigned long reclaim_high(struct mem_cgroup *memcg, unsigned int nr_pages, gfp_t gfp_mask) { unsigned long nr_reclaimed = 0; do { unsigned long pflags; if (page_counter_read(&memcg->memory) <= READ_ONCE(memcg->memory.high)) continue; memcg_memory_event(memcg, MEMCG_HIGH); psi_memstall_enter(&pflags); nr_reclaimed += try_to_free_mem_cgroup_pages(memcg, nr_pages, gfp_mask, MEMCG_RECLAIM_MAY_SWAP, NULL); psi_memstall_leave(&pflags); } while ((memcg = parent_mem_cgroup(memcg)) && !mem_cgroup_is_root(memcg)); return nr_reclaimed; } static void high_work_func(struct work_struct *work) { struct mem_cgroup *memcg; memcg = container_of(work, struct mem_cgroup, high_work); reclaim_high(memcg, MEMCG_CHARGE_BATCH, GFP_KERNEL); } /* * Clamp the maximum sleep time per allocation batch to 2 seconds. This is * enough to still cause a significant slowdown in most cases, while still * allowing diagnostics and tracing to proceed without becoming stuck. */ #define MEMCG_MAX_HIGH_DELAY_JIFFIES (2UL*HZ) /* * When calculating the delay, we use these either side of the exponentiation to * maintain precision and scale to a reasonable number of jiffies (see the table * below. * * - MEMCG_DELAY_PRECISION_SHIFT: Extra precision bits while translating the * overage ratio to a delay. * - MEMCG_DELAY_SCALING_SHIFT: The number of bits to scale down the * proposed penalty in order to reduce to a reasonable number of jiffies, and * to produce a reasonable delay curve. * * MEMCG_DELAY_SCALING_SHIFT just happens to be a number that produces a * reasonable delay curve compared to precision-adjusted overage, not * penalising heavily at first, but still making sure that growth beyond the * limit penalises misbehaviour cgroups by slowing them down exponentially. For * example, with a high of 100 megabytes: * * +-------+------------------------+ * | usage | time to allocate in ms | * +-------+------------------------+ * | 100M | 0 | * | 101M | 6 | * | 102M | 25 | * | 103M | 57 | * | 104M | 102 | * | 105M | 159 | * | 106M | 230 | * | 107M | 313 | * | 108M | 409 | * | 109M | 518 | * | 110M | 639 | * | 111M | 774 | * | 112M | 921 | * | 113M | 1081 | * | 114M | 1254 | * | 115M | 1439 | * | 116M | 1638 | * | 117M | 1849 | * | 118M | 2000 | * | 119M | 2000 | * | 120M | 2000 | * +-------+------------------------+ */ #define MEMCG_DELAY_PRECISION_SHIFT 20 #define MEMCG_DELAY_SCALING_SHIFT 14 static u64 calculate_overage(unsigned long usage, unsigned long high) { u64 overage; if (usage <= high) return 0; /* * Prevent division by 0 in overage calculation by acting as if * it was a threshold of 1 page */ high = max(high, 1UL); overage = usage - high; overage <<= MEMCG_DELAY_PRECISION_SHIFT; return div64_u64(overage, high); } static u64 mem_find_max_overage(struct mem_cgroup *memcg) { u64 overage, max_overage = 0; do { overage = calculate_overage(page_counter_read(&memcg->memory), READ_ONCE(memcg->memory.high)); max_overage = max(overage, max_overage); } while ((memcg = parent_mem_cgroup(memcg)) && !mem_cgroup_is_root(memcg)); return max_overage; } static u64 swap_find_max_overage(struct mem_cgroup *memcg) { u64 overage, max_overage = 0; do { overage = calculate_overage(page_counter_read(&memcg->swap), READ_ONCE(memcg->swap.high)); if (overage) memcg_memory_event(memcg, MEMCG_SWAP_HIGH); max_overage = max(overage, max_overage); } while ((memcg = parent_mem_cgroup(memcg)) && !mem_cgroup_is_root(memcg)); return max_overage; } /* * Get the number of jiffies that we should penalise a mischievous cgroup which * is exceeding its memory.high by checking both it and its ancestors. */ static unsigned long calculate_high_delay(struct mem_cgroup *memcg, unsigned int nr_pages, u64 max_overage) { unsigned long penalty_jiffies; if (!max_overage) return 0; /* * We use overage compared to memory.high to calculate the number of * jiffies to sleep (penalty_jiffies). Ideally this value should be * fairly lenient on small overages, and increasingly harsh when the * memcg in question makes it clear that it has no intention of stopping * its crazy behaviour, so we exponentially increase the delay based on * overage amount. */ penalty_jiffies = max_overage * max_overage * HZ; penalty_jiffies >>= MEMCG_DELAY_PRECISION_SHIFT; penalty_jiffies >>= MEMCG_DELAY_SCALING_SHIFT; /* * Factor in the task's own contribution to the overage, such that four * N-sized allocations are throttled approximately the same as one * 4N-sized allocation. * * MEMCG_CHARGE_BATCH pages is nominal, so work out how much smaller or * larger the current charge patch is than that. */ return penalty_jiffies * nr_pages / MEMCG_CHARGE_BATCH; } /* * 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(gfp_t gfp_mask) { unsigned long penalty_jiffies; unsigned long pflags; unsigned long nr_reclaimed; unsigned int nr_pages = current->memcg_nr_pages_over_high; int nr_retries = MAX_RECLAIM_RETRIES; struct mem_cgroup *memcg; bool in_retry = false; if (likely(!nr_pages)) return; memcg = get_mem_cgroup_from_mm(current->mm); current->memcg_nr_pages_over_high = 0; 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. * * This is distinct from memory.max or page allocator behaviour because * memory.high is currently batched, whereas memory.max and the page * allocator run every time an allocation is made. */ nr_reclaimed = reclaim_high(memcg, in_retry ? SWAP_CLUSTER_MAX : nr_pages, gfp_mask); /* * memory.high is breached and reclaim is unable to keep up. Throttle * allocators proactively to slow down excessive growth. */ penalty_jiffies = calculate_high_delay(memcg, nr_pages, mem_find_max_overage(memcg)); penalty_jiffies += calculate_high_delay(memcg, nr_pages, swap_find_max_overage(memcg)); /* * Clamp the max delay per usermode return so as to still keep the * application moving forwards and also permit diagnostics, albeit * extremely slowly. */ penalty_jiffies = min(penalty_jiffies, MEMCG_MAX_HIGH_DELAY_JIFFIES); /* * Don't sleep if the amount of jiffies this memcg owes us is so low * that it's not even worth doing, in an attempt to be nice to those who * go only a small amount over their memory.high value and maybe haven't * been aggressively reclaimed enough yet. */ if (penalty_jiffies <= HZ / 100) goto out; /* * If reclaim is making forward progress but we're still over * memory.high, we want to encourage that rather than doing allocator * throttling. */ if (nr_reclaimed || nr_retries--) { in_retry = true; goto 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. */ psi_memstall_enter(&pflags); schedule_timeout_killable(penalty_jiffies); psi_memstall_leave(&pflags); out: css_put(&memcg->css); } 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; unsigned long nr_reclaimed; bool passed_oom = false; unsigned int reclaim_options = MEMCG_RECLAIM_MAY_SWAP; bool drained = false; bool raised_max_event = false; unsigned long pflags; retry: if (consume_stock(memcg, nr_pages)) return 0; if (!do_memsw_account() || page_counter_try_charge(&memcg->memsw, batch, &counter)) { if (page_counter_try_charge(&memcg->memory, batch, &counter)) goto done_restock; if (do_memsw_account()) page_counter_uncharge(&memcg->memsw, batch); mem_over_limit = mem_cgroup_from_counter(counter, memory); } else { mem_over_limit = mem_cgroup_from_counter(counter, memsw); reclaim_options &= ~MEMCG_RECLAIM_MAY_SWAP; } if (batch > nr_pages) { batch = nr_pages; goto retry; } /* * 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 * under the limit over triggering OOM kills in these cases. */ if (unlikely(current->flags & PF_MEMALLOC)) goto force; if (unlikely(task_in_memcg_oom(current))) goto nomem; if (!gfpflags_allow_blocking(gfp_mask)) 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, reclaim_options, NULL); psi_memstall_leave(&pflags); if (mem_cgroup_margin(mem_over_limit) >= nr_pages) goto retry; if (!drained) { drain_all_stock(mem_over_limit); drained = true; goto retry; } if (gfp_mask & __GFP_NORETRY) goto nomem; /* * Even though the limit is exceeded at this point, reclaim * may have been able to free some pages. Retry the charge * before killing the task. * * Only for regular pages, though: huge pages are rather * unlikely to succeed so close to the limit, and we fall back * to regular pages anyway in case of failure. */ if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER)) goto retry; /* * At task move, charge accounts can be doubly counted. So, it's * better to wait until the end of task_move if something is going on. */ if (memcg1_wait_acct_move(mem_over_limit)) goto retry; if (nr_retries--) goto retry; if (gfp_mask & __GFP_RETRY_MAYFAIL) goto nomem; /* 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. */ 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; } nomem: /* * 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. */ page_counter_charge(&memcg->memory, nr_pages); if (do_memsw_account()) page_counter_charge(&memcg->memsw, nr_pages); return 0; done_restock: if (batch > nr_pages) refill_stock(memcg, batch - nr_pages); /* * If the hierarchy is above the normal consumption range, schedule * reclaim on returning to userland. We can perform reclaim here * if __GFP_RECLAIM but let's always punt for simplicity and so that * GFP_KERNEL can consistently be used during reclaim. @memcg is * not recorded as it most likely matches current's and won't * change in the meantime. As high limit is checked again before * reclaim, the cost of mismatch is negligible. */ do { bool mem_high, swap_high; mem_high = page_counter_read(&memcg->memory) > READ_ONCE(memcg->memory.high); swap_high = page_counter_read(&memcg->swap) > READ_ONCE(memcg->swap.high); /* Don't bother a random interrupted task */ if (!in_task()) { if (mem_high) { schedule_work(&memcg->high_work); break; } continue; } if (mem_high || swap_high) { /* * The allocating tasks in this cgroup will need to do * reclaim or be throttled to prevent further growth * of the memory or swap footprints. * * Target some best-effort fairness between the tasks, * and distribute reclaim work and delay penalties * based on how much each task is actually allocating. */ current->memcg_nr_pages_over_high += batch; set_notify_resume(current); break; } } 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; } /** * 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; page_counter_uncharge(&memcg->memory, nr_pages); if (do_memsw_account()) page_counter_uncharge(&memcg->memsw, nr_pages); } static void commit_charge(struct folio *folio, struct mem_cgroup *memcg) { VM_BUG_ON_FOLIO(folio_memcg(folio), folio); /* * Any of the following ensures page's memcg stability: * * - the page lock * - LRU isolation * - folio_memcg_lock() * - exclusive reference * - mem_cgroup_trylock_pages() */ 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)); memcg1_check_events(memcg, folio_nid(folio)); local_irq_enable(); } static inline void __mod_objcg_mlstate(struct obj_cgroup *objcg, struct pglist_data *pgdat, enum node_stat_item idx, int nr) { 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(); } 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->obj_exts. */ if (folio_test_slab(folio)) { struct slabobj_ext *obj_exts; struct slab *slab; unsigned int off; slab = folio_slab(folio); obj_exts = slab_obj_exts(slab); if (!obj_exts) return NULL; off = obj_to_index(slab->slab_cache, slab, p); if (obj_exts[off].objcg) return obj_cgroup_memcg(obj_exts[off].objcg); 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->obj_exts 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 folio *folio; if (mem_cgroup_disabled()) return NULL; if (unlikely(is_vmalloc_addr(p))) folio = page_folio(vmalloc_to_page(p)); else folio = virt_to_folio(p); 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; return mem_cgroup_from_obj_folio(virt_to_folio(p), p); } static struct obj_cgroup *__get_obj_cgroup_from_memcg(struct mem_cgroup *memcg) { struct obj_cgroup *objcg = 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; } return objcg; } static struct obj_cgroup *current_objcg_update(void) { struct mem_cgroup *memcg; struct obj_cgroup *old, *objcg = 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); obj_cgroup_put(old); old = NULL; } /* 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(); /* * 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; } __always_inline struct obj_cgroup *current_obj_cgroup(void) { struct mem_cgroup *memcg; struct obj_cgroup *objcg; if (in_task()) { memcg = current->active_memcg; if (unlikely(memcg)) goto from_memcg; 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; } memcg = this_cpu_read(int_active_memcg); if (unlikely(memcg)) goto from_memcg; return NULL; 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; } return objcg; } 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 objcg; } /* * 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); mod_memcg_state(memcg, MEMCG_KMEM, -nr_pages); memcg1_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. */ static int obj_cgroup_charge_pages(struct obj_cgroup *objcg, gfp_t gfp, unsigned int nr_pages) { struct mem_cgroup *memcg; int ret; memcg = get_mem_cgroup_from_objcg(objcg); ret = try_charge_memcg(memcg, gfp, nr_pages); if (ret) goto out; mod_memcg_state(memcg, MEMCG_KMEM, nr_pages); memcg1_account_kmem(memcg, nr_pages); out: css_put(&memcg->css); return ret; } /** * __memcg_kmem_charge_page: charge a kmem page to the current memory cgroup * @page: page to charge * @gfp: reclaim mode * @order: allocation order * * Returns 0 on success, an error code on failure. */ int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order) { struct obj_cgroup *objcg; int ret = 0; objcg = current_obj_cgroup(); if (objcg) { ret = obj_cgroup_charge_pages(objcg, gfp, 1 << order); if (!ret) { obj_cgroup_get(objcg); page->memcg_data = (unsigned long)objcg | MEMCG_DATA_KMEM; return 0; } } return ret; } /** * __memcg_kmem_uncharge_page: uncharge a kmem page * @page: page to uncharge * @order: allocation order */ void __memcg_kmem_uncharge_page(struct page *page, int order) { struct folio *folio = page_folio(page); struct obj_cgroup *objcg; unsigned int nr_pages = 1 << order; if (!folio_memcg_kmem(folio)) return; objcg = __folio_objcg(folio); obj_cgroup_uncharge_pages(objcg, nr_pages); folio->memcg_data = 0; obj_cgroup_put(objcg); } static 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; 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); obj_cgroup_put(old); } static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes) { struct memcg_stock_pcp *stock; unsigned long flags; bool ret = false; local_lock_irqsave(&memcg_stock.stock_lock, flags); stock = this_cpu_ptr(&memcg_stock); if (objcg == READ_ONCE(stock->cached_objcg) && stock->nr_bytes >= nr_bytes) { stock->nr_bytes -= nr_bytes; ret = true; } local_unlock_irqrestore(&memcg_stock.stock_lock, flags); return ret; } static struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock) { struct obj_cgroup *old = READ_ONCE(stock->cached_objcg); if (!old) 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) { struct mem_cgroup *memcg; memcg = get_mem_cgroup_from_objcg(old); mod_memcg_state(memcg, MEMCG_KMEM, -nr_pages); memcg1_account_kmem(memcg, -nr_pages); __refill_stock(memcg, nr_pages); css_put(&memcg->css); } /* * The leftover is flushed to the centralized per-memcg value. * On the next attempt to refill obj stock it will be moved * to a per-cpu stock (probably, on an other CPU), see * refill_obj_stock(). * * How often it's flushed is a trade-off between the memory * limit enforcement accuracy and potential CPU contention, * so it might be changed in the future. */ atomic_add(nr_bytes, &old->nr_charged_bytes); stock->nr_bytes = 0; } /* * 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 (objcg) { memcg = obj_cgroup_memcg(objcg); if (memcg && mem_cgroup_is_descendant(memcg, root_memcg)) return true; } return false; } 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_lock_irqsave(&memcg_stock.stock_lock, flags); stock = this_cpu_ptr(&memcg_stock); if (READ_ONCE(stock->cached_objcg) != objcg) { /* reset if necessary */ old = drain_obj_stock(stock); obj_cgroup_get(objcg); 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 (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); obj_cgroup_put(old); if (nr_pages) obj_cgroup_uncharge_pages(objcg, nr_pages); } int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size) { unsigned int nr_pages, nr_bytes; int ret; if (consume_obj_stock(objcg, size)) return 0; /* * In theory, objcg->nr_charged_bytes can have enough * pre-charged bytes to satisfy the allocation. However, * 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. */ nr_pages = size >> PAGE_SHIFT; nr_bytes = size & (PAGE_SIZE - 1); if (nr_bytes) nr_pages += 1; ret = obj_cgroup_charge_pages(objcg, gfp, nr_pages); if (!ret && nr_bytes) refill_obj_stock(objcg, PAGE_SIZE - nr_bytes, false); return ret; } void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size) { refill_obj_stock(objcg, size, true); } static inline size_t obj_full_size(struct kmem_cache *s) { /* * For each accounted object there is an extra space which is used * to store obj_cgroup membership. Charge it too. */ return s->size + sizeof(struct obj_cgroup *); } bool __memcg_slab_post_alloc_hook(struct kmem_cache *s, struct list_lru *lru, gfp_t flags, size_t size, void **p) { struct obj_cgroup *objcg; struct slab *slab; unsigned long off; size_t i; /* * The obtained objcg pointer is safe to use within the current scope, * defined by current task or set_active_memcg() pair. * obj_cgroup_get() is used to get a permanent reference. */ objcg = current_obj_cgroup(); if (!objcg) return true; /* * slab_alloc_node() avoids the NULL check, so we might be called with a * single NULL object. kmem_cache_alloc_bulk() aborts if it can't fill * the whole requested size. * return success as there's nothing to free back */ if (unlikely(*p == NULL)) return true; flags &= gfp_allowed_mask; if (lru) { int ret; struct mem_cgroup *memcg; memcg = get_mem_cgroup_from_objcg(objcg); ret = memcg_list_lru_alloc(memcg, lru, flags); css_put(&memcg->css); if (ret) return false; } if (obj_cgroup_charge(objcg, flags, size * obj_full_size(s))) return false; for (i = 0; i < size; i++) { slab = virt_to_slab(p[i]); if (!slab_obj_exts(slab) && alloc_slab_obj_exts(slab, s, flags, false)) { obj_cgroup_uncharge(objcg, obj_full_size(s)); continue; } off = obj_to_index(s, slab, p[i]); obj_cgroup_get(objcg); slab_obj_exts(slab)[off].objcg = objcg; mod_objcg_state(objcg, slab_pgdat(slab), cache_vmstat_idx(s), obj_full_size(s)); } return true; } void __memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab, void **p, int objects, struct slabobj_ext *obj_exts) { for (int i = 0; i < objects; i++) { struct obj_cgroup *objcg; unsigned int off; off = obj_to_index(s, slab, p[i]); objcg = obj_exts[off].objcg; if (!objcg) continue; obj_exts[off].objcg = NULL; obj_cgroup_uncharge(objcg, obj_full_size(s)); mod_objcg_state(objcg, slab_pgdat(slab), cache_vmstat_idx(s), -obj_full_size(s)); obj_cgroup_put(objcg); } } /* * Because folio_memcg(head) is not set on tails, set it now. */ void split_page_memcg(struct page *head, int old_order, int new_order) { struct folio *folio = page_folio(head); struct mem_cgroup *memcg = folio_memcg(folio); int i; unsigned int old_nr = 1 << old_order; unsigned int new_nr = 1 << new_order; if (mem_cgroup_disabled() || !memcg) return; for (i = new_nr; i < old_nr; i += new_nr) folio_page(folio, i)->memcg_data = folio->memcg_data; if (folio_memcg_kmem(folio)) obj_cgroup_get_many(__folio_objcg(folio), old_nr / new_nr - 1); else css_get_many(&memcg->css, old_nr / new_nr - 1); } unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) { unsigned long val; if (mem_cgroup_is_root(memcg)) { /* * 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 += total_swap_pages - get_nr_swap_pages(); } else { if (!swap) val = page_counter_read(&memcg->memory); else val = page_counter_read(&memcg->memsw); } return val; } static int memcg_online_kmem(struct mem_cgroup *memcg) { struct obj_cgroup *objcg; if (mem_cgroup_kmem_disabled()) return 0; if (unlikely(mem_cgroup_is_root(memcg))) return 0; objcg = obj_cgroup_alloc(); 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_online_key); memcg->kmemcg_id = memcg->id.id; return 0; } static void memcg_offline_kmem(struct mem_cgroup *memcg) { struct mem_cgroup *parent; if (mem_cgroup_kmem_disabled()) return; if (unlikely(mem_cgroup_is_root(memcg))) return; parent = parent_mem_cgroup(memcg); if (!parent) parent = root_mem_cgroup; memcg_reparent_objcgs(memcg, parent); /* * 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(). */ memcg_reparent_list_lrus(memcg, parent); } #ifdef CONFIG_CGROUP_WRITEBACK #include <trace/events/writeback.h> static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp) { return wb_domain_init(&memcg->cgwb_domain, gfp); } static void memcg_wb_domain_exit(struct mem_cgroup *memcg) { wb_domain_exit(&memcg->cgwb_domain); } static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg) { wb_domain_size_changed(&memcg->cgwb_domain); } struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb) { struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css); if (!memcg->css.parent) return NULL; return &memcg->cgwb_domain; } /** * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg * @wb: bdi_writeback in question * @pfilepages: out parameter for number of file pages * @pheadroom: out parameter for number of allocatable pages according to memcg * @pdirty: out parameter for number of dirty pages * @pwriteback: out parameter for number of pages under writeback * * Determine the numbers of file, headroom, dirty, and writeback pages in * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom * is a bit more involved. * * A memcg's headroom is "min(max, high) - used". In the hierarchy, the * headroom is calculated as the lowest headroom of itself and the * ancestors. Note that this doesn't consider the actual amount of * available memory in the system. The caller should further cap * *@pheadroom accordingly. */ void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages, unsigned long *pheadroom, unsigned long *pdirty, unsigned long *pwriteback) { struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css); struct mem_cgroup *parent; mem_cgroup_flush_stats_ratelimited(memcg); *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)); unsigned long used = page_counter_read(&memcg->memory); *pheadroom = min(*pheadroom, ceiling - min(ceiling, used)); memcg = parent; } } /* * Foreign dirty flushing * * There's an inherent mismatch between memcg and writeback. The former * 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 * different cgroups isn't a common use-case. * * Combined with inode majority-writer ownership switching, this works well * enough in most cases but there are some pathological cases. For * example, let's say there are two cgroups A and B which keep writing to * different but confined parts of the same inode. B owns the inode and * A's memory is limited far below B's. A's dirty ratio can rise enough to * trigger balance_dirty_pages() sleeps but B's can be low enough to avoid * 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 repeatedly and * severely throttled after making some progress after each * dirty_expire_interval while the underlying IO device is almost * completely idle. * * Solving this problem completely requires matching the ownership tracking * granularities between memcg and writeback in either direction. However, * the more egregious behaviors can be avoided by simply remembering the * most recent foreign dirtying events and initiating remote flushes on * them when local writeback isn't enough to keep the memory clean enough. * * The following two functions implement such mechanism. When a foreign * page - a page whose memcg and writeback ownerships don't match - is * dirtied, mem_cgroup_track_foreign_dirty() records the inode owning * bdi_writeback on the page owning memcg. When balance_dirty_pages() * decides that the memcg needs to sleep due to high dirty ratio, it calls * mem_cgroup_flush_foreign() which queues writeback on the recorded * foreign bdi_writebacks which haven't expired. Both the numbers of * recorded bdi_writebacks and concurrent in-flight foreign writebacks are * limited to MEMCG_CGWB_FRN_CNT. * * The mechanism only remembers IDs and doesn't hold any object references. * 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 folio *folio, struct bdi_writeback *wb) { 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(folio, wb); /* * Pick the slot to use. If there is already a slot for @wb, keep * using it. If not replace the oldest one which isn't being * written out. */ for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) { frn = &memcg->cgwb_frn[i]; if (frn->bdi_id == wb->bdi->id && frn->memcg_id == wb->memcg_css->id) break; if (time_before64(frn->at, oldest_at) && atomic_read(&frn->done.cnt) == 1) { oldest = i; oldest_at = frn->at; } } if (i < MEMCG_CGWB_FRN_CNT) { /* * Re-using an existing one. Update timestamp lazily to * avoid making the cacheline hot. We want them to be * reasonably up-to-date and significantly shorter than * dirty_expire_interval as that's what expires the record. * Use the shorter of 1s and dirty_expire_interval / 8. */ unsigned long update_intv = min_t(unsigned long, HZ, msecs_to_jiffies(dirty_expire_interval * 10) / 8); if (time_before64(frn->at, now - update_intv)) frn->at = now; } else if (oldest >= 0) { /* replace the oldest free one */ frn = &memcg->cgwb_frn[oldest]; frn->bdi_id = wb->bdi->id; frn->memcg_id = wb->memcg_css->id; frn->at = now; } } /* issue foreign writeback flushes for recorded foreign dirtying events */ void mem_cgroup_flush_foreign(struct bdi_writeback *wb) { struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css); unsigned long intv = msecs_to_jiffies(dirty_expire_interval * 10); u64 now = jiffies_64; int i; for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) { struct memcg_cgwb_frn *frn = &memcg->cgwb_frn[i]; /* * If the record is older than dirty_expire_interval, * writeback on it has already started. No need to kick it * off again. Also, don't start a new one if there's * already one in flight. */ if (time_after64(frn->at, now - intv) && 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, WB_REASON_FOREIGN_FLUSH, &frn->done); } } } #else /* CONFIG_CGROUP_WRITEBACK */ static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp) { return 0; } static void memcg_wb_domain_exit(struct mem_cgroup *memcg) { } static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg) { } #endif /* CONFIG_CGROUP_WRITEBACK */ /* * Private memory cgroup IDR * * Swap-out records and page cache shadow entries need to store memcg * references in constrained space, so we maintain an ID space that is * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of * memory-controlled cgroups to 64k. * * However, there usually are many references to the offline CSS after * the cgroup has been destroyed, such as page cache or reclaimable * slab objects, that don't need to hang on to the ID. We want to keep * those dead CSS from occupying IDs, or we might quickly exhaust the * relatively small ID space and prevent the creation of new cgroups * even when there are much fewer than 64k cgroups - possibly none. * * Maintain a private 16-bit ID space for memcg, and allow the ID to * be freed and recycled when it's no longer needed, which is usually * when the CSS is offlined. * * The only exception to that are records of swapped out tmpfs/shmem * pages that need to be attributed to live ancestors on swapin. But * those references are manageable from userspace. */ #define MEM_CGROUP_ID_MAX ((1UL << MEM_CGROUP_ID_SHIFT) - 1) static DEFINE_IDR(mem_cgroup_idr); static DEFINE_SPINLOCK(memcg_idr_lock); static int mem_cgroup_alloc_id(void) { int ret; idr_preload(GFP_KERNEL); spin_lock(&memcg_idr_lock); ret = idr_alloc(&mem_cgroup_idr, NULL, 1, MEM_CGROUP_ID_MAX + 1, GFP_NOWAIT); spin_unlock(&memcg_idr_lock); idr_preload_end(); return ret; } static void mem_cgroup_id_remove(struct mem_cgroup *memcg) { if (memcg->id.id > 0) { spin_lock(&memcg_idr_lock); idr_remove(&mem_cgroup_idr, memcg->id.id); spin_unlock(&memcg_idr_lock); memcg->id.id = 0; } } void __maybe_unused mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n) { refcount_add(n, &memcg->id.ref); } void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n) { if (refcount_sub_and_test(n, &memcg->id.ref)) { mem_cgroup_id_remove(memcg); /* Memcg ID pins CSS */ css_put(&memcg->css); } } static inline void mem_cgroup_id_put(struct mem_cgroup *memcg) { mem_cgroup_id_put_many(memcg, 1); } /** * mem_cgroup_from_id - look up a memcg from a memcg id * @id: the memcg id to look up * * Caller must hold rcu_read_lock(). */ struct mem_cgroup *mem_cgroup_from_id(unsigned short id) { WARN_ON_ONCE(!rcu_read_lock_held()); 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 bool alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node) { struct mem_cgroup_per_node *pn; pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, node); if (!pn) return false; pn->lruvec_stats = kzalloc_node(sizeof(struct lruvec_stats), GFP_KERNEL_ACCOUNT, node); if (!pn->lruvec_stats) goto fail; pn->lruvec_stats_percpu = alloc_percpu_gfp(struct lruvec_stats_percpu, GFP_KERNEL_ACCOUNT); if (!pn->lruvec_stats_percpu) goto fail; lruvec_init(&pn->lruvec); pn->memcg = memcg; memcg->nodeinfo[node] = pn; return true; fail: kfree(pn->lruvec_stats); kfree(pn); return false; } static void free_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node) { struct mem_cgroup_per_node *pn = memcg->nodeinfo[node]; if (!pn) return; free_percpu(pn->lruvec_stats_percpu); kfree(pn->lruvec_stats); kfree(pn); } static void __mem_cgroup_free(struct mem_cgroup *memcg) { int node; 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); kfree(memcg); } static void mem_cgroup_free(struct mem_cgroup *memcg) { lru_gen_exit_memcg(memcg); memcg_wb_domain_exit(memcg); __mem_cgroup_free(memcg); } static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent) { struct memcg_vmstats_percpu *statc, *pstatc; struct mem_cgroup *memcg; int node, cpu; int __maybe_unused i; long error = -ENOMEM; memcg = kzalloc(struct_size(memcg, nodeinfo, nr_node_ids), GFP_KERNEL); if (!memcg) return ERR_PTR(error); memcg->id.id = mem_cgroup_alloc_id(); if (memcg->id.id < 0) { error = memcg->id.id; goto fail; } memcg->vmstats = kzalloc(sizeof(struct memcg_vmstats), GFP_KERNEL_ACCOUNT); if (!memcg->vmstats) goto fail; memcg->vmstats_percpu = alloc_percpu_gfp(struct memcg_vmstats_percpu, GFP_KERNEL_ACCOUNT); 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; if (memcg_wb_domain_init(memcg, GFP_KERNEL)) goto fail; INIT_WORK(&memcg->high_work, high_work_func); vmpressure_init(&memcg->vmpressure); memcg->socket_pressure = jiffies; memcg1_memcg_init(memcg); memcg->kmemcg_id = -1; INIT_LIST_HEAD(&memcg->objcg_list); #ifdef CONFIG_CGROUP_WRITEBACK INIT_LIST_HEAD(&memcg->cgwb_list); for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) memcg->cgwb_frn[i].done = __WB_COMPLETION_INIT(&memcg_cgwb_frn_waitq); #endif #ifdef CONFIG_TRANSPARENT_HUGEPAGE spin_lock_init(&memcg->deferred_split_queue.split_queue_lock); INIT_LIST_HEAD(&memcg->deferred_split_queue.split_queue); memcg->deferred_split_queue.split_queue_len = 0; #endif lru_gen_init_memcg(memcg); return memcg; fail: mem_cgroup_id_remove(memcg); __mem_cgroup_free(memcg); return ERR_PTR(error); } static struct cgroup_subsys_state * __ref 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; old_memcg = set_active_memcg(parent); 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); memcg1_soft_limit_reset(memcg); #ifdef CONFIG_ZSWAP memcg->zswap_max = PAGE_COUNTER_MAX; WRITE_ONCE(memcg->zswap_writeback, true); #endif page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX); if (parent) { WRITE_ONCE(memcg->swappiness, mem_cgroup_swappiness(parent)); page_counter_init(&memcg->memory, &parent->memory); page_counter_init(&memcg->swap, &parent->swap); #ifdef CONFIG_MEMCG_V1 WRITE_ONCE(memcg->oom_kill_disable, READ_ONCE(parent->oom_kill_disable)); page_counter_init(&memcg->kmem, &parent->kmem); page_counter_init(&memcg->tcpmem, &parent->tcpmem); #endif } else { init_memcg_stats(); init_memcg_events(); page_counter_init(&memcg->memory, NULL); page_counter_init(&memcg->swap, NULL); #ifdef CONFIG_MEMCG_V1 page_counter_init(&memcg->kmem, NULL); page_counter_init(&memcg->tcpmem, NULL); #endif root_mem_cgroup = memcg; return &memcg->css; } if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket) static_branch_inc(&memcg_sockets_enabled_key); if (!cgroup_memory_nobpf) static_branch_inc(&memcg_bpf_enabled_key); return &memcg->css; } 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 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 (alloc_shrinker_info(memcg)) goto offline_kmem; if (unlikely(mem_cgroup_is_root(memcg)) && !mem_cgroup_disabled()) 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. */ spin_lock(&memcg_idr_lock); idr_replace(&mem_cgroup_idr, memcg, memcg->id.id); spin_unlock(&memcg_idr_lock); 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) { struct mem_cgroup *memcg = mem_cgroup_from_css(css); memcg1_css_offline(memcg); 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); mem_cgroup_id_put(memcg); } 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) { struct mem_cgroup *memcg = mem_cgroup_from_css(css); int __maybe_unused i; #ifdef CONFIG_CGROUP_WRITEBACK for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) wb_wait_for_completion(&memcg->cgwb_frn[i].done); #endif if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket) static_branch_dec(&memcg_sockets_enabled_key); if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg1_tcpmem_active(memcg)) static_branch_dec(&memcg_sockets_enabled_key); if (!cgroup_memory_nobpf) static_branch_dec(&memcg_bpf_enabled_key); vmpressure_cleanup(&memcg->vmpressure); cancel_work_sync(&memcg->high_work); memcg1_remove_from_trees(memcg); free_shrinker_info(memcg); mem_cgroup_free(memcg); } /** * mem_cgroup_css_reset - reset the states of a mem_cgroup * @css: the target css * * Reset the states of the mem_cgroup associated with @css. This is * invoked when the userland requests disabling on the default hierarchy * but the memcg is pinned through dependency. The memcg should stop * applying policies and should revert to the vanilla state as it may be * made visible again. * * The current implementation only resets the essential configurations. * This needs to be expanded to cover all the visible parts. */ static void mem_cgroup_css_reset(struct cgroup_subsys_state *css) { struct mem_cgroup *memcg = mem_cgroup_from_css(css); page_counter_set_max(&memcg->memory, PAGE_COUNTER_MAX); page_counter_set_max(&memcg->swap, PAGE_COUNTER_MAX); #ifdef CONFIG_MEMCG_V1 page_counter_set_max(&memcg->kmem, PAGE_COUNTER_MAX); page_counter_set_max(&memcg->tcpmem, PAGE_COUNTER_MAX); #endif page_counter_set_min(&memcg->memory, 0); page_counter_set_low(&memcg->memory, 0); page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX); memcg1_soft_limit_reset(memcg); 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_VMSTAT_SIZE; 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 lruvec_stats *lstats = pn->lruvec_stats; struct lruvec_stats *plstats = NULL; struct lruvec_stats_percpu *lstatc; if (parent) plstats = parent->nodeinfo[nid]->lruvec_stats; lstatc = per_cpu_ptr(pn->lruvec_stats_percpu, cpu); for (i = 0; i < NR_MEMCG_NODE_STAT_ITEMS; i++) { delta = lstats->state_pending[i]; if (delta) lstats->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) lstats->state_local[i] += delta_cpu; if (delta) { lstats->state[i] += delta; if (plstats) plstats->state_pending[i] += delta; } } } WRITE_ONCE(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); } static void mem_cgroup_fork(struct task_struct *task) { /* * 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(). */ 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); 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; } #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 */ 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); } } static void mem_cgroup_attach(struct cgroup_taskset *tset) { mem_cgroup_lru_gen_attach(tset); mem_cgroup_kmem_attach(tset); } static int seq_puts_memcg_tunable(struct seq_file *m, unsigned long value) { if (value == PAGE_COUNTER_MAX) seq_puts(m, "max\n"); else seq_printf(m, "%llu\n", (u64)value * PAGE_SIZE); return 0; } static u64 memory_current_read(struct cgroup_subsys_state *css, struct cftype *cft) { struct mem_cgroup *memcg = mem_cgroup_from_css(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, READ_ONCE(mem_cgroup_from_seq(m)->memory.min)); } static ssize_t memory_min_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 min; int err; buf = strstrip(buf); err = page_counter_memparse(buf, "max", &min); if (err) return err; page_counter_set_min(&memcg->memory, min); return nbytes; } static int memory_low_show(struct seq_file *m, void *v) { return seq_puts_memcg_tunable(m, READ_ONCE(mem_cgroup_from_seq(m)->memory.low)); } static ssize_t memory_low_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 low; int err; buf = strstrip(buf); err = page_counter_memparse(buf, "max", &low); if (err) return err; page_counter_set_low(&memcg->memory, low); return nbytes; } static int memory_high_show(struct seq_file *m, void *v) { return seq_puts_memcg_tunable(m, READ_ONCE(mem_cgroup_from_seq(m)->memory.high)); } static ssize_t memory_high_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 int nr_retries = MAX_RECLAIM_RETRIES; bool drained = false; unsigned long high; int err; buf = strstrip(buf); err = page_counter_memparse(buf, "max", &high); if (err) return err; page_counter_set_high(&memcg->memory, high); for (;;) { unsigned long nr_pages = page_counter_read(&memcg->memory); unsigned long reclaimed; if (nr_pages <= high) break; if (signal_pending(current)) break; if (!drained) { drain_all_stock(memcg); drained = true; continue; } reclaimed = try_to_free_mem_cgroup_pages(memcg, nr_pages - high, GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP, NULL); if (!reclaimed && !nr_retries--) break; } memcg_wb_domain_size_changed(memcg); return nbytes; } static int memory_max_show(struct seq_file *m, void *v) { return seq_puts_memcg_tunable(m, READ_ONCE(mem_cgroup_from_seq(m)->memory.max)); } static ssize_t memory_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 int nr_reclaims = MAX_RECLAIM_RETRIES; bool drained = false; unsigned long max; int err; buf = strstrip(buf); err = page_counter_memparse(buf, "max", &max); if (err) return err; xchg(&memcg->memory.max, max); for (;;) { unsigned long nr_pages = page_counter_read(&memcg->memory); if (nr_pages <= max) break; if (signal_pending(current)) break; if (!drained) { drain_all_stock(memcg); drained = true; continue; } if (nr_reclaims) { if (!try_to_free_mem_cgroup_pages(memcg, nr_pages - max, GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP, NULL)) nr_reclaims--; continue; } memcg_memory_event(memcg, MEMCG_OOM); if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0)) break; } memcg_wb_domain_size_changed(memcg); 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])); seq_printf(m, "high %lu\n", atomic_long_read(&events[MEMCG_HIGH])); seq_printf(m, "max %lu\n", atomic_long_read(&events[MEMCG_MAX])); 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) { struct mem_cgroup *memcg = mem_cgroup_from_seq(m); __memory_events_show(m, memcg->memory_events); return 0; } static int memory_events_local_show(struct seq_file *m, void *v) { struct mem_cgroup *memcg = mem_cgroup_from_seq(m); __memory_events_show(m, memcg->memory_events_local); return 0; } int memory_stat_show(struct seq_file *m, void *v) { struct mem_cgroup *memcg = mem_cgroup_from_seq(m); char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL); struct seq_buf s; 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; if (memory_stats[i].idx >= NR_VM_NODE_STAT_ITEMS) continue; seq_printf(m, "%s", memory_stats[i].name); for_each_node_state(nid, N_MEMORY) { u64 size; struct lruvec *lruvec; lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid)); size = lruvec_page_state_output(lruvec, memory_stats[i].idx); seq_printf(m, " N%d=%llu", nid, size); } seq_putc(m, '\n'); } return 0; } #endif 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", READ_ONCE(memcg->oom_group)); return 0; } static ssize_t memory_oom_group_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 ret, oom_group; buf = strstrip(buf); if (!buf) return -EINVAL; ret = kstrtoint(buf, 0, &oom_group); if (ret) return ret; if (oom_group != 0 && oom_group != 1) return -EINVAL; WRITE_ONCE(memcg->oom_group, oom_group); return nbytes; } enum { MEMORY_RECLAIM_SWAPPINESS = 0, MEMORY_RECLAIM_NULL, }; static const match_table_t tokens = { { MEMORY_RECLAIM_SWAPPINESS, "swappiness=%d"}, { MEMORY_RECLAIM_NULL, NULL }, }; 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; int swappiness = -1; unsigned int reclaim_options; char *old_buf, *start; substring_t args[MAX_OPT_ARGS]; buf = strstrip(buf); old_buf = buf; nr_to_reclaim = memparse(buf, &buf) / PAGE_SIZE; if (buf == old_buf) return -EINVAL; buf = strstrip(buf); while ((start = strsep(&buf, " ")) != NULL) { if (!strlen(start)) continue; switch (match_token(start, tokens, args)) { case MEMORY_RECLAIM_SWAPPINESS: if (match_int(&args[0], &swappiness)) return -EINVAL; if (swappiness < MIN_SWAPPINESS || swappiness > MAX_SWAPPINESS) return -EINVAL; break; default: return -EINVAL; } } reclaim_options = MEMCG_RECLAIM_MAY_SWAP | MEMCG_RECLAIM_PROACTIVE; while (nr_reclaimed < nr_to_reclaim) { /* Will converge on zero, but reclaim enforces a minimum */ unsigned long batch_size = (nr_to_reclaim - nr_reclaimed) / 4; 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, batch_size, GFP_KERNEL, reclaim_options, swappiness == -1 ? NULL : &swappiness); if (!reclaimed && !nr_retries--) return -EAGAIN; nr_reclaimed += reclaimed; } return nbytes; } static struct cftype memory_files[] = { { .name = "current", .flags = CFTYPE_NOT_ON_ROOT, .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, .write = memory_min_write, }, { .name = "low", .flags = CFTYPE_NOT_ON_ROOT, .seq_show = memory_low_show, .write = memory_low_write, }, { .name = "high", .flags = CFTYPE_NOT_ON_ROOT, .seq_show = memory_high_show, .write = memory_high_write, }, { .name = "max", .flags = CFTYPE_NOT_ON_ROOT, .seq_show = memory_max_show, .write = memory_max_write, }, { .name = "events", .flags = CFTYPE_NOT_ON_ROOT, .file_offset = offsetof(struct mem_cgroup, events_file), .seq_show = memory_events_show, }, { .name = "events.local", .flags = CFTYPE_NOT_ON_ROOT, .file_offset = offsetof(struct mem_cgroup, events_local_file), .seq_show = memory_events_local_show, }, { .name = "stat", .seq_show = memory_stat_show, }, #ifdef CONFIG_NUMA { .name = "numa_stat", .seq_show = memory_numa_stat_show, }, #endif { .name = "oom.group", .flags = CFTYPE_NOT_ON_ROOT | CFTYPE_NS_DELEGATABLE, .seq_show = memory_oom_group_show, .write = memory_oom_group_write, }, { .name = "reclaim", .flags = CFTYPE_NS_DELEGATABLE, .write = memory_reclaim, }, { } /* terminate */ }; struct cgroup_subsys memory_cgrp_subsys = { .css_alloc = mem_cgroup_css_alloc, .css_online = mem_cgroup_css_online, .css_offline = mem_cgroup_css_offline, .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, .attach = mem_cgroup_attach, .fork = mem_cgroup_fork, .exit = mem_cgroup_exit, .dfl_cftypes = memory_files, #ifdef CONFIG_MEMCG_V1 .can_attach = memcg1_can_attach, .cancel_attach = memcg1_cancel_attach, .post_attach = memcg1_move_task, .legacy_cftypes = mem_cgroup_legacy_files, #endif .early_init = 0, }; /** * 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 * * WARNING: This function is not stateless! It can only be used as part * of a top-down tree iteration, not for isolated queries. */ void mem_cgroup_calculate_protection(struct mem_cgroup *root, struct mem_cgroup *memcg) { bool recursive_protection = cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_RECURSIVE_PROT; if (mem_cgroup_disabled()) return; if (!root) root = root_mem_cgroup; page_counter_calculate_protection(&root->memory, &memcg->memory, recursive_protection); } 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_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. * * 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_hugetlb_try_charge(struct mem_cgroup *memcg, gfp_t gfp, long nr_pages) { /* * 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 (try_charge(memcg, gfp, nr_pages)) return -ENOMEM; return 0; } /** * 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; if (mem_cgroup_disabled()) return 0; 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 = charge_memcg(folio, memcg, gfp); css_put(&memcg->css); return ret; } /* * 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, 1); } } struct uncharge_gather { struct mem_cgroup *memcg; unsigned long nr_memory; unsigned long pgpgout; unsigned long nr_kmem; int nid; }; static inline void uncharge_gather_clear(struct uncharge_gather *ug) { memset(ug, 0, sizeof(*ug)); } static void uncharge_batch(const struct uncharge_gather *ug) { unsigned long flags; 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_memory); if (ug->nr_kmem) { mod_memcg_state(ug->memcg, MEMCG_KMEM, -ug->nr_kmem); memcg1_account_kmem(ug->memcg, -ug->nr_kmem); } memcg1_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_memory); memcg1_check_events(ug->memcg, ug->nid); local_irq_restore(flags); /* drop reference from uncharge_folio */ css_put(&ug->memcg->css); } static void uncharge_folio(struct folio *folio, struct uncharge_gather *ug) { long nr_pages; struct mem_cgroup *memcg; struct obj_cgroup *objcg; VM_BUG_ON_FOLIO(folio_test_lru(folio), folio); VM_BUG_ON_FOLIO(folio_order(folio) > 1 && !folio_test_hugetlb(folio) && !list_empty(&folio->_deferred_list), folio); /* * Nobody should be changing or seriously looking at * 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 (!memcg) return; if (ug->memcg != memcg) { if (ug->memcg) { uncharge_batch(ug); uncharge_gather_clear(ug); } ug->memcg = memcg; ug->nid = folio_nid(folio); /* pairs with css_put in uncharge_batch */ css_get(&memcg->css); } nr_pages = folio_nr_pages(folio); if (folio_memcg_kmem(folio)) { ug->nr_memory += nr_pages; ug->nr_kmem += nr_pages; 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++; folio->memcg_data = 0; } css_put(&memcg->css); } void __mem_cgroup_uncharge(struct folio *folio) { struct uncharge_gather ug; /* Don't touch folio->lru of any random page, pre-check: */ if (!folio_memcg(folio)) return; uncharge_gather_clear(&ug); uncharge_folio(folio, &ug); uncharge_batch(&ug); } void __mem_cgroup_uncharge_folios(struct folio_batch *folios) { struct uncharge_gather ug; unsigned int i; uncharge_gather_clear(&ug); for (i = 0; i < folios->nr; i++) uncharge_folio(folios->folios[i], &ug); if (ug.memcg) uncharge_batch(&ug); } /** * mem_cgroup_replace_folio - Charge a folio's replacement. * @old: Currently circulating folio. * @new: Replacement folio. * * Charge @new as a replacement folio for @old. @old will * be uncharged upon free. * * Both folios must be locked, @new->mapping must be set up. */ void mem_cgroup_replace_folio(struct folio *old, struct folio *new) { struct mem_cgroup *memcg; long nr_pages = folio_nr_pages(new); unsigned long flags; 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 folio already charged? */ if (folio_memcg(new)) return; 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 */ 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(new, memcg); local_irq_save(flags); mem_cgroup_charge_statistics(memcg, nr_pages); memcg1_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); VM_BUG_ON_FOLIO(folio_test_lru(old), old); 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); old->memcg_data = 0; } DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key); EXPORT_SYMBOL(memcg_sockets_enabled_key); void mem_cgroup_sk_alloc(struct sock *sk) { struct mem_cgroup *memcg; if (!mem_cgroup_sockets_enabled) return; /* Do not associate the sock with unrelated interrupted task's memcg. */ if (!in_task()) return; rcu_read_lock(); memcg = mem_cgroup_from_task(current); if (mem_cgroup_is_root(memcg)) goto out; if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg1_tcpmem_active(memcg)) goto out; if (css_tryget(&memcg->css)) sk->sk_memcg = memcg; out: rcu_read_unlock(); } void mem_cgroup_sk_free(struct sock *sk) { if (sk->sk_memcg) css_put(&sk->sk_memcg->css); } /** * 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 it doesn't. */ bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages, gfp_t gfp_mask) { if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) return memcg1_charge_skmem(memcg, nr_pages, gfp_mask); if (try_charge(memcg, gfp_mask, nr_pages) == 0) { mod_memcg_state(memcg, MEMCG_SOCK, nr_pages); return true; } return false; } /** * mem_cgroup_uncharge_skmem - uncharge socket memory * @memcg: memcg to uncharge * @nr_pages: number of pages to uncharge */ void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages) { if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) { memcg1_uncharge_skmem(memcg, nr_pages); return; } mod_memcg_state(memcg, MEMCG_SOCK, -nr_pages); refill_stock(memcg, nr_pages); } static int __init cgroup_memory(char *s) { char *token; while ((token = strsep(&s, ",")) != NULL) { if (!*token) continue; if (!strcmp(token, "nosocket")) cgroup_memory_nosocket = true; if (!strcmp(token, "nokmem")) cgroup_memory_nokmem = true; if (!strcmp(token, "nobpf")) cgroup_memory_nobpf = true; } return 1; } __setup("cgroup.memory=", cgroup_memory); /* * subsys_initcall() for memory controller. * * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this * context because of lock dependencies (cgroup_lock -> cpu hotplug) but * basically everything that doesn't depend on a specific mem_cgroup structure * should be initialized from here. */ static int __init mem_cgroup_init(void) { int cpu; /* * 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); for_each_possible_cpu(cpu) INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work, drain_local_stock); return 0; } subsys_initcall(mem_cgroup_init); #ifdef CONFIG_SWAP static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg) { while (!refcount_inc_not_zero(&memcg->id.ref)) { /* * The root cgroup cannot be destroyed, so it's refcount must * always be >= 1. */ if (WARN_ON_ONCE(mem_cgroup_is_root(memcg))) { VM_BUG_ON(1); break; } memcg = parent_mem_cgroup(memcg); if (!memcg) memcg = root_mem_cgroup; } return memcg; } /** * mem_cgroup_swapout - transfer a memsw charge to swap * @folio: folio whose memsw charge to transfer * @entry: swap entry to move the charge to * * Transfer the memsw charge of @folio to @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_FOLIO(folio_test_lru(folio), folio); VM_BUG_ON_FOLIO(folio_ref_count(folio), folio); if (mem_cgroup_disabled()) return; if (!do_memsw_account()) return; memcg = folio_memcg(folio); VM_WARN_ON_ONCE_FOLIO(!memcg, folio); if (!memcg) return; /* * In case the memcg owning these pages has been offlined and doesn't * have an ID allocated to it anymore, charge the closest online * ancestor for the swap instead and transfer the memory+swap charge. */ swap_memcg = mem_cgroup_id_get_online(memcg); 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_FOLIO(oldid, folio); mod_memcg_state(swap_memcg, MEMCG_SWAP, nr_entries); folio->memcg_data = 0; if (!mem_cgroup_is_root(memcg)) page_counter_uncharge(&memcg->memory, nr_entries); 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); } /* * Interrupts should be disabled here because the caller holds the * i_pages lock which is taken with interrupts-off. It is * important here to have the interrupts disabled because it is the * only synchronisation we have for updating the per-CPU variables. */ memcg_stats_lock(); mem_cgroup_charge_statistics(memcg, -nr_entries); memcg_stats_unlock(); memcg1_check_events(memcg, folio_nid(folio)); css_put(&memcg->css); } /** * __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 @folio's memcg for the swap space at @entry. * * Returns 0 on success, -ENOMEM on failure. */ int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry) { unsigned int nr_pages = folio_nr_pages(folio); struct page_counter *counter; struct mem_cgroup *memcg; unsigned short oldid; if (do_memsw_account()) return 0; memcg = folio_memcg(folio); VM_WARN_ON_ONCE_FOLIO(!memcg, folio); if (!memcg) return 0; if (!entry.val) { memcg_memory_event(memcg, MEMCG_SWAP_FAIL); return 0; } memcg = mem_cgroup_id_get_online(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); mem_cgroup_id_put(memcg); return -ENOMEM; } /* Get references for the tail pages, too */ 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_FOLIO(oldid, folio); mod_memcg_state(memcg, MEMCG_SWAP, nr_pages); return 0; } /** * __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) { struct mem_cgroup *memcg; unsigned short id; id = swap_cgroup_record(entry, 0, nr_pages); rcu_read_lock(); memcg = mem_cgroup_from_id(id); if (memcg) { 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); } rcu_read_unlock(); } long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) { long nr_swap_pages = get_nr_swap_pages(); if (mem_cgroup_disabled() || do_memsw_account()) return nr_swap_pages; 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 folio *folio) { struct mem_cgroup *memcg; VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); if (vm_swap_full()) return true; if (do_memsw_account()) return false; memcg = folio_memcg(folio); if (!memcg) return false; 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) || usage * 2 >= READ_ONCE(memcg->swap.max)) return true; } return false; } static int __init setup_swap_account(char *s) { 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); static u64 swap_current_read(struct cgroup_subsys_state *css, struct cftype *cft) { struct mem_cgroup *memcg = mem_cgroup_from_css(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, READ_ONCE(mem_cgroup_from_seq(m)->swap.high)); } static ssize_t swap_high_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 high; int err; buf = strstrip(buf); err = page_counter_memparse(buf, "max", &high); if (err) return err; page_counter_set_high(&memcg->swap, high); return nbytes; } static int swap_max_show(struct seq_file *m, void *v) { return seq_puts_memcg_tunable(m, READ_ONCE(mem_cgroup_from_seq(m)->swap.max)); } static ssize_t swap_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->swap.max, max); return nbytes; } static int swap_events_show(struct seq_file *m, void *v) { struct mem_cgroup *memcg = mem_cgroup_from_seq(m); seq_printf(m, "high %lu\n", atomic_long_read(&memcg->memory_events[MEMCG_SWAP_HIGH])); seq_printf(m, "max %lu\n", atomic_long_read(&memcg->memory_events[MEMCG_SWAP_MAX])); seq_printf(m, "fail %lu\n", atomic_long_read(&memcg->memory_events[MEMCG_SWAP_FAIL])); return 0; } static struct cftype swap_files[] = { { .name = "swap.current", .flags = CFTYPE_NOT_ON_ROOT, .read_u64 = swap_current_read, }, { .name = "swap.high", .flags = CFTYPE_NOT_ON_ROOT, .seq_show = swap_high_show, .write = swap_high_write, }, { .name = "swap.max", .flags = CFTYPE_NOT_ON_ROOT, .seq_show = swap_max_show, .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), .seq_show = swap_events_show, }, { } /* terminate */ }; #ifdef 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 */ if (!zswap_is_enabled()) return true; for (; memcg; memcg = parent_mem_cgroup(memcg)) if (!READ_ONCE(memcg->zswap_writeback)) return false; return true; } 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_ZSWAP */ static int __init mem_cgroup_swap_init(void) { if (mem_cgroup_disabled()) return 0; WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, swap_files)); #ifdef CONFIG_MEMCG_V1 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, memsw_files)); #endif #ifdef CONFIG_ZSWAP WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, zswap_files)); #endif return 0; } subsys_initcall(mem_cgroup_swap_init); #endif /* CONFIG_SWAP */
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