diff options
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 514 |
1 files changed, 109 insertions, 405 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 03a6f7506..c57c4423c 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -111,56 +111,10 @@ static const char * const mem_cgroup_lru_names[] = { "unevictable", }; -/* - * Per memcg event counter is incremented at every pagein/pageout. With THP, - * it will be incremated by the number of pages. This counter is used for - * for trigger some periodic events. This is straightforward and better - * than using jiffies etc. to handle periodic memcg event. - */ -enum mem_cgroup_events_target { - MEM_CGROUP_TARGET_THRESH, - MEM_CGROUP_TARGET_SOFTLIMIT, - MEM_CGROUP_TARGET_NUMAINFO, - MEM_CGROUP_NTARGETS, -}; #define THRESHOLDS_EVENTS_TARGET 128 #define SOFTLIMIT_EVENTS_TARGET 1024 #define NUMAINFO_EVENTS_TARGET 1024 -struct mem_cgroup_stat_cpu { - long count[MEM_CGROUP_STAT_NSTATS]; - unsigned long events[MEMCG_NR_EVENTS]; - unsigned long nr_page_events; - unsigned long targets[MEM_CGROUP_NTARGETS]; -}; - -struct reclaim_iter { - struct mem_cgroup *position; - /* scan generation, increased every round-trip */ - unsigned int generation; -}; - -/* - * per-zone information in memory controller. - */ -struct mem_cgroup_per_zone { - struct lruvec lruvec; - unsigned long lru_size[NR_LRU_LISTS]; - - struct reclaim_iter iter[DEF_PRIORITY + 1]; - - struct rb_node tree_node; /* RB tree node */ - unsigned long usage_in_excess;/* Set to the value by which */ - /* the soft limit is exceeded*/ - bool on_tree; - struct mem_cgroup *memcg; /* Back pointer, we cannot */ - /* use container_of */ -}; - -struct mem_cgroup_per_node { - struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; -}; - /* * Cgroups above their limits are maintained in a RB-Tree, independent of * their hierarchy representation @@ -181,32 +135,6 @@ struct mem_cgroup_tree { static struct mem_cgroup_tree soft_limit_tree __read_mostly; -struct mem_cgroup_threshold { - struct eventfd_ctx *eventfd; - unsigned long threshold; -}; - -/* For threshold */ -struct mem_cgroup_threshold_ary { - /* An array index points to threshold just below or equal to usage. */ - int current_threshold; - /* Size of entries[] */ - unsigned int size; - /* Array of thresholds */ - struct mem_cgroup_threshold entries[0]; -}; - -struct mem_cgroup_thresholds { - /* Primary thresholds array */ - struct mem_cgroup_threshold_ary *primary; - /* - * Spare threshold array. - * This is needed to make mem_cgroup_unregister_event() "never fail". - * It must be able to store at least primary->size - 1 entries. - */ - struct mem_cgroup_threshold_ary *spare; -}; - /* for OOM */ struct mem_cgroup_eventfd_list { struct list_head list; @@ -256,113 +184,6 @@ struct mem_cgroup_event { static void mem_cgroup_threshold(struct mem_cgroup *memcg); static void mem_cgroup_oom_notify(struct mem_cgroup *memcg); -/* - * The memory controller data structure. The memory controller controls both - * page cache and RSS per cgroup. We would eventually like to provide - * statistics based on the statistics developed by Rik Van Riel for clock-pro, - * to help the administrator determine what knobs to tune. - */ -struct mem_cgroup { - struct cgroup_subsys_state css; - - /* Accounted resources */ - struct page_counter memory; - struct page_counter memsw; - struct page_counter kmem; - - /* Normal memory consumption range */ - unsigned long low; - unsigned long high; - - unsigned long soft_limit; - - /* vmpressure notifications */ - struct vmpressure vmpressure; - - /* css_online() has been completed */ - int initialized; - - /* - * Should the accounting and control be hierarchical, per subtree? - */ - bool use_hierarchy; - - /* protected by memcg_oom_lock */ - bool oom_lock; - int under_oom; - - int swappiness; - /* OOM-Killer disable */ - int oom_kill_disable; - - /* protect arrays of thresholds */ - struct mutex thresholds_lock; - - /* thresholds for memory usage. RCU-protected */ - struct mem_cgroup_thresholds thresholds; - - /* thresholds for mem+swap usage. RCU-protected */ - struct mem_cgroup_thresholds memsw_thresholds; - - /* For oom notifier event fd */ - struct list_head oom_notify; - - /* - * Should we move charges of a task when a task is moved into this - * mem_cgroup ? And what type of charges should we move ? - */ - unsigned long move_charge_at_immigrate; - /* - * set > 0 if pages under this cgroup are moving to other cgroup. - */ - atomic_t moving_account; - /* taken only while moving_account > 0 */ - spinlock_t move_lock; - struct task_struct *move_lock_task; - unsigned long move_lock_flags; - /* - * percpu counter. - */ - struct mem_cgroup_stat_cpu __percpu *stat; - spinlock_t pcp_counter_lock; - -#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET) - struct cg_proto tcp_mem; -#endif -#if defined(CONFIG_MEMCG_KMEM) - /* Index in the kmem_cache->memcg_params.memcg_caches array */ - int kmemcg_id; - bool kmem_acct_activated; - bool kmem_acct_active; -#endif - - int last_scanned_node; -#if MAX_NUMNODES > 1 - nodemask_t scan_nodes; - atomic_t numainfo_events; - atomic_t numainfo_updating; -#endif - -#ifdef CONFIG_CGROUP_WRITEBACK - struct list_head cgwb_list; - struct wb_domain cgwb_domain; -#endif - - /* List of events which userspace want to receive */ - struct list_head event_list; - spinlock_t event_list_lock; - - struct mem_cgroup_per_node *nodeinfo[0]; - /* WARNING: nodeinfo must be the last member here */ -}; - -#ifdef CONFIG_MEMCG_KMEM -bool memcg_kmem_is_active(struct mem_cgroup *memcg) -{ - return memcg->kmem_acct_active; -} -#endif - /* Stuffs for move charges at task migration. */ /* * Types of charges to be moved. @@ -423,11 +244,6 @@ enum res_type { */ static DEFINE_MUTEX(memcg_create_mutex); -struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s) -{ - return s ? container_of(s, struct mem_cgroup, css) : NULL; -} - /* Some nice accessors for the vmpressure. */ struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg) { @@ -499,8 +315,7 @@ void sock_update_memcg(struct sock *sk) rcu_read_lock(); memcg = mem_cgroup_from_task(current); cg_proto = sk->sk_prot->proto_cgroup(memcg); - if (!mem_cgroup_is_root(memcg) && - memcg_proto_active(cg_proto) && + if (cg_proto && test_bit(MEMCG_SOCK_ACTIVE, &cg_proto->flags) && css_tryget_online(&memcg->css)) { sk->sk_cgrp = cg_proto; } @@ -593,11 +408,6 @@ mem_cgroup_zone_zoneinfo(struct mem_cgroup *memcg, struct zone *zone) return &memcg->nodeinfo[nid]->zoneinfo[zid]; } -struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg) -{ - return &memcg->css; -} - /** * mem_cgroup_css_from_page - css of the memcg associated with a page * @page: page of interest @@ -631,6 +441,34 @@ struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page) 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(); + memcg = READ_ONCE(page->mem_cgroup); + 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; +} + static struct mem_cgroup_per_zone * mem_cgroup_page_zoneinfo(struct mem_cgroup *memcg, struct page *page) { @@ -885,14 +723,6 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, __this_cpu_add(memcg->stat->nr_page_events, nr_pages); } -unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru) -{ - struct mem_cgroup_per_zone *mz; - - mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec); - return mz->lru_size[lru]; -} - static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg, int nid, unsigned int lru_mask) @@ -995,6 +825,7 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) return mem_cgroup_from_css(task_css(p, memory_cgrp_id)); } +EXPORT_SYMBOL(mem_cgroup_from_task); static struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) { @@ -1040,7 +871,7 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, struct mem_cgroup *prev, struct mem_cgroup_reclaim_cookie *reclaim) { - struct reclaim_iter *uninitialized_var(iter); + struct mem_cgroup_reclaim_iter *uninitialized_var(iter); struct cgroup_subsys_state *css = NULL; struct mem_cgroup *memcg = NULL; struct mem_cgroup *pos = NULL; @@ -1182,30 +1013,6 @@ void mem_cgroup_iter_break(struct mem_cgroup *root, iter != NULL; \ iter = mem_cgroup_iter(NULL, iter, NULL)) -void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx) -{ - struct mem_cgroup *memcg; - - rcu_read_lock(); - memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); - if (unlikely(!memcg)) - goto out; - - switch (idx) { - case PGFAULT: - this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]); - break; - case PGMAJFAULT: - this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]); - break; - default: - BUG(); - } -out: - rcu_read_unlock(); -} -EXPORT_SYMBOL(__mem_cgroup_count_vm_event); - /** * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg * @zone: zone of the wanted lruvec @@ -1304,15 +1111,6 @@ void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru, VM_BUG_ON((long)(*lru_size) < 0); } -bool mem_cgroup_is_descendant(struct mem_cgroup *memcg, struct mem_cgroup *root) -{ - if (root == memcg) - return true; - if (!root->use_hierarchy) - return false; - return cgroup_is_descendant(memcg->css.cgroup, root->css.cgroup); -} - bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg) { struct mem_cgroup *task_memcg; @@ -1339,39 +1137,6 @@ bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg) return ret; } -int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec) -{ - unsigned long inactive_ratio; - unsigned long inactive; - unsigned long active; - unsigned long gb; - - inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON); - active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON); - - gb = (inactive + active) >> (30 - PAGE_SHIFT); - if (gb) - inactive_ratio = int_sqrt(10 * gb); - else - inactive_ratio = 1; - - return inactive * inactive_ratio < active; -} - -bool mem_cgroup_lruvec_online(struct lruvec *lruvec) -{ - struct mem_cgroup_per_zone *mz; - struct mem_cgroup *memcg; - - if (mem_cgroup_disabled()) - return true; - - mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec); - memcg = mz->memcg; - - return !!(memcg->css.flags & CSS_ONLINE); -} - #define mem_cgroup_from_counter(counter, member) \ container_of(counter, struct mem_cgroup, member) @@ -1403,15 +1168,6 @@ static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg) return margin; } -int mem_cgroup_swappiness(struct mem_cgroup *memcg) -{ - /* root ? */ - if (mem_cgroup_disabled() || !memcg->css.parent) - return vm_swappiness; - - return memcg->swappiness; -} - /* * A routine for checking "mem" is under move_account() or not. * @@ -1554,6 +1310,12 @@ static unsigned long mem_cgroup_get_limit(struct mem_cgroup *memcg) static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, int order) { + struct oom_control oc = { + .zonelist = NULL, + .nodemask = NULL, + .gfp_mask = gfp_mask, + .order = order, + }; struct mem_cgroup *iter; unsigned long chosen_points = 0; unsigned long totalpages; @@ -1572,7 +1334,7 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, goto unlock; } - check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL, memcg); + check_panic_on_oom(&oc, CONSTRAINT_MEMCG, memcg); totalpages = mem_cgroup_get_limit(memcg) ? : 1; for_each_mem_cgroup_tree(iter, memcg) { struct css_task_iter it; @@ -1580,8 +1342,7 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, css_task_iter_start(&iter->css, &it); while ((task = css_task_iter_next(&it))) { - switch (oom_scan_process_thread(task, totalpages, NULL, - false)) { + switch (oom_scan_process_thread(&oc, task, totalpages)) { case OOM_SCAN_SELECT: if (chosen) put_task_struct(chosen); @@ -1619,8 +1380,8 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, if (chosen) { points = chosen_points * 1000 / totalpages; - oom_kill_process(chosen, gfp_mask, order, points, totalpages, - memcg, NULL, "Memory cgroup out of memory"); + oom_kill_process(&oc, chosen, points, totalpages, memcg, + "Memory cgroup out of memory"); } unlock: mutex_unlock(&oom_lock); @@ -2071,23 +1832,6 @@ void mem_cgroup_end_page_stat(struct mem_cgroup *memcg) } EXPORT_SYMBOL(mem_cgroup_end_page_stat); -/** - * mem_cgroup_update_page_stat - update page state statistics - * @memcg: memcg to account against - * @idx: page state item to account - * @val: number of pages (positive or negative) - * - * See mem_cgroup_begin_page_stat() for locking requirements. - */ -void mem_cgroup_update_page_stat(struct mem_cgroup *memcg, - enum mem_cgroup_stat_index idx, int val) -{ - VM_BUG_ON(!rcu_read_lock_held()); - - if (memcg) - this_cpu_add(memcg->stat->count[idx], val); -} - /* * size of first charge trial. "32" comes from vmscan.c's magic value. * TODO: maybe necessary to use big numbers in big irons. @@ -2364,40 +2108,6 @@ static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages) css_put_many(&memcg->css, nr_pages); } -/* - * try_get_mem_cgroup_from_page - look up page's memcg association - * @page: the page - * - * Look up, get a css reference, and return the memcg that owns @page. - * - * The page must be locked to prevent racing with swap-in and page - * cache charges. If coming from an unlocked page table, the caller - * must ensure the page is on the LRU or this can race with charging. - */ -struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) -{ - struct mem_cgroup *memcg; - unsigned short id; - swp_entry_t ent; - - VM_BUG_ON_PAGE(!PageLocked(page), page); - - memcg = page->mem_cgroup; - if (memcg) { - if (!css_tryget_online(&memcg->css)) - memcg = NULL; - } else if (PageSwapCache(page)) { - ent.val = page_private(page); - id = lookup_swap_cgroup_id(ent); - rcu_read_lock(); - memcg = mem_cgroup_from_id(id); - if (memcg && !css_tryget_online(&memcg->css)) - memcg = NULL; - rcu_read_unlock(); - } - return memcg; -} - static void lock_page_lru(struct page *page, int *isolated) { struct zone *zone = page_zone(page); @@ -2513,16 +2223,6 @@ void memcg_uncharge_kmem(struct mem_cgroup *memcg, unsigned long nr_pages) css_put_many(&memcg->css, nr_pages); } -/* - * helper for acessing a memcg's index. It will be used as an index in the - * child cache array in kmem_cache, and also to derive its name. This function - * will return -1 when this is not a kmem-limited memcg. - */ -int memcg_cache_id(struct mem_cgroup *memcg) -{ - return memcg ? memcg->kmemcg_id : -1; -} - static int memcg_alloc_cache_id(void) { int id, size; @@ -4041,44 +3741,43 @@ struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb) /** * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg * @wb: bdi_writeback in question - * @pavail: out parameter for number of available pages + * @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 available, dirty, and writeback pages in @wb's - * memcg. Dirty and writeback are self-explanatory. Available is a bit - * more involved. + * 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". The available memory is - * calculated as the lowest headroom of itself and the ancestors plus the - * number of pages already being used for file pages. Note that this - * doesn't consider the actual amount of available memory in the system. - * The caller should further cap *@pavail accordingly. + * 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 *pavail, - unsigned long *pdirty, unsigned long *pwriteback) +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; - unsigned long head_room = PAGE_COUNTER_MAX; - unsigned long file_pages; *pdirty = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_DIRTY); /* this should eventually include NR_UNSTABLE_NFS */ *pwriteback = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_WRITEBACK); + *pfilepages = mem_cgroup_nr_lru_pages(memcg, (1 << LRU_INACTIVE_FILE) | + (1 << LRU_ACTIVE_FILE)); + *pheadroom = PAGE_COUNTER_MAX; - file_pages = mem_cgroup_nr_lru_pages(memcg, (1 << LRU_INACTIVE_FILE) | - (1 << LRU_ACTIVE_FILE)); while ((parent = parent_mem_cgroup(memcg))) { unsigned long ceiling = min(memcg->memory.limit, memcg->high); unsigned long used = page_counter_read(&memcg->memory); - head_room = min(head_room, ceiling - min(ceiling, used)); + *pheadroom = min(*pheadroom, ceiling - min(ceiling, used)); memcg = parent; } - - *pavail = file_pages + head_room; } #else /* CONFIG_CGROUP_WRITEBACK */ @@ -4486,7 +4185,6 @@ static struct mem_cgroup *mem_cgroup_alloc(void) if (memcg_wb_domain_init(memcg, GFP_KERNEL)) goto out_free_stat; - spin_lock_init(&memcg->pcp_counter_lock); return memcg; out_free_stat: @@ -5134,10 +4832,12 @@ static void mem_cgroup_clear_mc(void) static int mem_cgroup_can_attach(struct cgroup_subsys_state *css, struct cgroup_taskset *tset) { - struct task_struct *p = cgroup_taskset_first(tset); - int ret = 0; struct mem_cgroup *memcg = mem_cgroup_from_css(css); + struct mem_cgroup *from; + struct task_struct *p; + struct mm_struct *mm; unsigned long move_flags; + int ret = 0; /* * We are now commited to this value whatever it is. Changes in this @@ -5145,36 +4845,37 @@ static int mem_cgroup_can_attach(struct cgroup_subsys_state *css, * So we need to save it, and keep it going. */ move_flags = READ_ONCE(memcg->move_charge_at_immigrate); - if (move_flags) { - struct mm_struct *mm; - struct mem_cgroup *from = mem_cgroup_from_task(p); + if (!move_flags) + return 0; - VM_BUG_ON(from == memcg); + p = cgroup_taskset_first(tset); + from = mem_cgroup_from_task(p); - mm = get_task_mm(p); - if (!mm) - return 0; - /* We move charges only when we move a owner of the mm */ - if (mm->owner == p) { - VM_BUG_ON(mc.from); - VM_BUG_ON(mc.to); - VM_BUG_ON(mc.precharge); - VM_BUG_ON(mc.moved_charge); - VM_BUG_ON(mc.moved_swap); - - spin_lock(&mc.lock); - mc.from = from; - mc.to = memcg; - mc.flags = move_flags; - spin_unlock(&mc.lock); - /* We set mc.moving_task later */ - - ret = mem_cgroup_precharge_mc(mm); - if (ret) - mem_cgroup_clear_mc(); - } - mmput(mm); + VM_BUG_ON(from == memcg); + + mm = get_task_mm(p); + if (!mm) + return 0; + /* We move charges only when we move a owner of the mm */ + if (mm->owner == p) { + VM_BUG_ON(mc.from); + VM_BUG_ON(mc.to); + VM_BUG_ON(mc.precharge); + VM_BUG_ON(mc.moved_charge); + VM_BUG_ON(mc.moved_swap); + + spin_lock(&mc.lock); + mc.from = from; + mc.to = memcg; + mc.flags = move_flags; + spin_unlock(&mc.lock); + /* We set mc.moving_task later */ + + ret = mem_cgroup_precharge_mc(mm); + if (ret) + mem_cgroup_clear_mc(); } + mmput(mm); return ret; } @@ -5528,19 +5229,6 @@ struct cgroup_subsys memory_cgrp_subsys = { }; /** - * mem_cgroup_events - count memory events against a cgroup - * @memcg: the memory cgroup - * @idx: the event index - * @nr: the number of events to account for - */ -void mem_cgroup_events(struct mem_cgroup *memcg, - enum mem_cgroup_events_index idx, - unsigned int nr) -{ - this_cpu_add(memcg->stat->events[idx], nr); -} - -/** * mem_cgroup_low - check if memory consumption is below the normal range * @root: the highest ancestor to consider * @memcg: the memory cgroup to check @@ -5612,8 +5300,20 @@ int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm, * the page lock, which serializes swap cache removal, which * in turn serializes uncharging. */ + VM_BUG_ON_PAGE(!PageLocked(page), page); if (page->mem_cgroup) goto out; + + if (do_swap_account) { + swp_entry_t ent = { .val = page_private(page), }; + unsigned short id = lookup_swap_cgroup_id(ent); + + rcu_read_lock(); + memcg = mem_cgroup_from_id(id); + if (memcg && !css_tryget_online(&memcg->css)) + memcg = NULL; + rcu_read_unlock(); + } } if (PageTransHuge(page)) { @@ -5621,8 +5321,6 @@ int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm, VM_BUG_ON_PAGE(!PageTransHuge(page), page); } - if (do_swap_account && PageSwapCache(page)) - memcg = try_get_mem_cgroup_from_page(page); if (!memcg) memcg = get_mem_cgroup_from_mm(mm); @@ -5972,7 +5670,13 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry) if (!mem_cgroup_is_root(memcg)) page_counter_uncharge(&memcg->memory, 1); - /* Caller disabled preemption with mapping->tree_lock */ + /* + * Interrupts should be disabled here because the caller holds the + * mapping->tree_lock 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 udpating the per-CPU variables. + */ + VM_BUG_ON(!irqs_disabled()); mem_cgroup_charge_statistics(memcg, page, -1); memcg_check_events(memcg, page); } |