diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memcontrol.c | 257 |
1 files changed, 84 insertions, 173 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 6937f16f5ecb..f6bc78f4ed13 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -250,13 +250,6 @@ enum res_type { /* Used for OOM nofiier */ #define OOM_CONTROL (0) -/* - * The memcg_create_mutex will be held whenever a new cgroup is created. - * As a consequence, any change that needs to protect against new child cgroups - * appearing has to hold it as well. - */ -static DEFINE_MUTEX(memcg_create_mutex); - /* Some nice accessors for the vmpressure. */ struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg) { @@ -899,17 +892,8 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, if (css == &root->css) break; - if (css_tryget(css)) { - /* - * Make sure the memcg is initialized: - * mem_cgroup_css_online() orders the the - * initialization against setting the flag. - */ - if (smp_load_acquire(&memcg->initialized)) - break; - - css_put(css); - } + if (css_tryget(css)) + break; memcg = NULL; } @@ -2690,14 +2674,6 @@ static inline bool memcg_has_children(struct mem_cgroup *memcg) { bool ret; - /* - * The lock does not prevent addition or deletion of children, but - * it prevents a new child from being initialized based on this - * parent in css_online(), so it's enough to decide whether - * hierarchically inherited attributes can still be changed or not. - */ - lockdep_assert_held(&memcg_create_mutex); - rcu_read_lock(); ret = css_next_child(NULL, &memcg->css); rcu_read_unlock(); @@ -2760,10 +2736,8 @@ static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css, struct mem_cgroup *memcg = mem_cgroup_from_css(css); struct mem_cgroup *parent_memcg = mem_cgroup_from_css(memcg->css.parent); - mutex_lock(&memcg_create_mutex); - if (memcg->use_hierarchy == val) - goto out; + return 0; /* * If parent's use_hierarchy is set, we can't make any modifications @@ -2782,9 +2756,6 @@ static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css, } else retval = -EINVAL; -out: - mutex_unlock(&memcg_create_mutex); - return retval; } @@ -2872,37 +2843,14 @@ static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css, #ifndef CONFIG_SLOB static int memcg_online_kmem(struct mem_cgroup *memcg) { - int err = 0; int memcg_id; BUG_ON(memcg->kmemcg_id >= 0); BUG_ON(memcg->kmem_state); - /* - * For simplicity, we won't allow this to be disabled. It also can't - * be changed if the cgroup has children already, or if tasks had - * already joined. - * - * If tasks join before we set the limit, a person looking at - * kmem.usage_in_bytes will have no way to determine when it took - * place, which makes the value quite meaningless. - * - * After it first became limited, changes in the value of the limit are - * of course permitted. - */ - mutex_lock(&memcg_create_mutex); - if (cgroup_is_populated(memcg->css.cgroup) || - (memcg->use_hierarchy && memcg_has_children(memcg))) - err = -EBUSY; - mutex_unlock(&memcg_create_mutex); - if (err) - goto out; - memcg_id = memcg_alloc_cache_id(); - if (memcg_id < 0) { - err = memcg_id; - goto out; - } + if (memcg_id < 0) + return memcg_id; static_branch_inc(&memcg_kmem_enabled_key); /* @@ -2913,17 +2861,14 @@ static int memcg_online_kmem(struct mem_cgroup *memcg) */ memcg->kmemcg_id = memcg_id; memcg->kmem_state = KMEM_ONLINE; -out: - return err; + + return 0; } -static int memcg_propagate_kmem(struct mem_cgroup *memcg) +static int memcg_propagate_kmem(struct mem_cgroup *parent, + struct mem_cgroup *memcg) { int ret = 0; - struct mem_cgroup *parent = parent_mem_cgroup(memcg); - - if (!parent) - return 0; mutex_lock(&memcg_limit_mutex); /* @@ -2985,6 +2930,10 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg) static void memcg_free_kmem(struct mem_cgroup *memcg) { + /* css_alloc() failed, offlining didn't happen */ + if (unlikely(memcg->kmem_state == KMEM_ONLINE)) + memcg_offline_kmem(memcg); + if (memcg->kmem_state == KMEM_ALLOCATED) { memcg_destroy_kmem_caches(memcg); static_branch_dec(&memcg_kmem_enabled_key); @@ -2992,7 +2941,11 @@ static void memcg_free_kmem(struct mem_cgroup *memcg) } } #else -static int memcg_propagate_kmem(struct mem_cgroup *memcg) +static int memcg_propagate_kmem(struct mem_cgroup *parent, struct mem_cgroup *memcg) +{ + return 0; +} +static int memcg_online_kmem(struct mem_cgroup *memcg) { return 0; } @@ -3007,11 +2960,16 @@ static void memcg_free_kmem(struct mem_cgroup *memcg) static int memcg_update_kmem_limit(struct mem_cgroup *memcg, unsigned long limit) { - int ret; + int ret = 0; mutex_lock(&memcg_limit_mutex); /* Top-level cgroup doesn't propagate from root */ if (!memcg_kmem_online(memcg)) { + if (cgroup_is_populated(memcg->css.cgroup) || + (memcg->use_hierarchy && memcg_has_children(memcg))) + ret = -EBUSY; + if (ret) + goto out; ret = memcg_online_kmem(memcg); if (ret) goto out; @@ -4167,90 +4125,44 @@ static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node) kfree(memcg->nodeinfo[node]); } -static struct mem_cgroup *mem_cgroup_alloc(void) -{ - struct mem_cgroup *memcg; - size_t size; - - size = sizeof(struct mem_cgroup); - size += nr_node_ids * sizeof(struct mem_cgroup_per_node *); - - memcg = kzalloc(size, GFP_KERNEL); - if (!memcg) - return NULL; - - memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu); - if (!memcg->stat) - goto out_free; - - if (memcg_wb_domain_init(memcg, GFP_KERNEL)) - goto out_free_stat; - - return memcg; - -out_free_stat: - free_percpu(memcg->stat); -out_free: - kfree(memcg); - return NULL; -} - -/* - * At destroying mem_cgroup, references from swap_cgroup can remain. - * (scanning all at force_empty is too costly...) - * - * Instead of clearing all references at force_empty, we remember - * the number of reference from swap_cgroup and free mem_cgroup when - * it goes down to 0. - * - * Removal of cgroup itself succeeds regardless of refs from swap. - */ - -static void __mem_cgroup_free(struct mem_cgroup *memcg) +static void mem_cgroup_free(struct mem_cgroup *memcg) { int node; - cancel_work_sync(&memcg->high_work); - - mem_cgroup_remove_from_trees(memcg); - + memcg_wb_domain_exit(memcg); for_each_node(node) free_mem_cgroup_per_zone_info(memcg, node); - free_percpu(memcg->stat); - memcg_wb_domain_exit(memcg); kfree(memcg); } -static struct cgroup_subsys_state * __ref -mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) +static struct mem_cgroup *mem_cgroup_alloc(void) { struct mem_cgroup *memcg; - long error = -ENOMEM; + size_t size; int node; - memcg = mem_cgroup_alloc(); + size = sizeof(struct mem_cgroup); + size += nr_node_ids * sizeof(struct mem_cgroup_per_node *); + + memcg = kzalloc(size, GFP_KERNEL); if (!memcg) - return ERR_PTR(error); + return NULL; + + memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu); + if (!memcg->stat) + goto fail; for_each_node(node) if (alloc_mem_cgroup_per_zone_info(memcg, node)) - goto free_out; + goto fail; - /* root ? */ - if (parent_css == NULL) { - root_mem_cgroup = memcg; - page_counter_init(&memcg->memory, NULL); - memcg->high = PAGE_COUNTER_MAX; - memcg->soft_limit = PAGE_COUNTER_MAX; - page_counter_init(&memcg->memsw, NULL); - page_counter_init(&memcg->kmem, NULL); - } + if (memcg_wb_domain_init(memcg, GFP_KERNEL)) + goto fail; INIT_WORK(&memcg->high_work, high_work_func); memcg->last_scanned_node = MAX_NUMNODES; INIT_LIST_HEAD(&memcg->oom_notify); - memcg->move_charge_at_immigrate = 0; mutex_init(&memcg->thresholds_lock); spin_lock_init(&memcg->move_lock); vmpressure_init(&memcg->vmpressure); @@ -4263,48 +4175,37 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) #ifdef CONFIG_CGROUP_WRITEBACK INIT_LIST_HEAD(&memcg->cgwb_list); #endif - return &memcg->css; - -free_out: - __mem_cgroup_free(memcg); - return ERR_PTR(error); + return memcg; +fail: + mem_cgroup_free(memcg); + return NULL; } -static int -mem_cgroup_css_online(struct cgroup_subsys_state *css) +static struct cgroup_subsys_state * __ref +mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) { - struct mem_cgroup *memcg = mem_cgroup_from_css(css); - struct mem_cgroup *parent = mem_cgroup_from_css(css->parent); - int ret; - - if (css->id > MEM_CGROUP_ID_MAX) - return -ENOSPC; - - if (!parent) - return 0; - - mutex_lock(&memcg_create_mutex); + struct mem_cgroup *parent = mem_cgroup_from_css(parent_css); + struct mem_cgroup *memcg; + long error = -ENOMEM; - memcg->use_hierarchy = parent->use_hierarchy; - memcg->oom_kill_disable = parent->oom_kill_disable; - memcg->swappiness = mem_cgroup_swappiness(parent); + memcg = mem_cgroup_alloc(); + if (!memcg) + return ERR_PTR(error); - if (parent->use_hierarchy) { + memcg->high = PAGE_COUNTER_MAX; + memcg->soft_limit = PAGE_COUNTER_MAX; + if (parent) { + memcg->swappiness = mem_cgroup_swappiness(parent); + memcg->oom_kill_disable = parent->oom_kill_disable; + } + if (parent && parent->use_hierarchy) { + memcg->use_hierarchy = true; page_counter_init(&memcg->memory, &parent->memory); - memcg->high = PAGE_COUNTER_MAX; - memcg->soft_limit = PAGE_COUNTER_MAX; page_counter_init(&memcg->memsw, &parent->memsw); page_counter_init(&memcg->kmem, &parent->kmem); page_counter_init(&memcg->tcpmem, &parent->tcpmem); - - /* - * No need to take a reference to the parent because cgroup - * core guarantees its existence. - */ } else { page_counter_init(&memcg->memory, NULL); - memcg->high = PAGE_COUNTER_MAX; - memcg->soft_limit = PAGE_COUNTER_MAX; page_counter_init(&memcg->memsw, NULL); page_counter_init(&memcg->kmem, NULL); page_counter_init(&memcg->tcpmem, NULL); @@ -4316,21 +4217,31 @@ mem_cgroup_css_online(struct cgroup_subsys_state *css) if (parent != root_mem_cgroup) memory_cgrp_subsys.broken_hierarchy = true; } - mutex_unlock(&memcg_create_mutex); - ret = memcg_propagate_kmem(memcg); - if (ret) - return ret; + /* The following stuff does not apply to the root */ + if (!parent) { + root_mem_cgroup = memcg; + return &memcg->css; + } + + error = memcg_propagate_kmem(parent, memcg); + if (error) + goto fail; if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket) static_branch_inc(&memcg_sockets_enabled_key); - /* - * Make sure the memcg is initialized: mem_cgroup_iter() - * orders reading memcg->initialized against its callers - * reading the memcg members. - */ - smp_store_release(&memcg->initialized, 1); + return &memcg->css; +fail: + mem_cgroup_free(memcg); + return NULL; +} + +static int +mem_cgroup_css_online(struct cgroup_subsys_state *css) +{ + if (css->id > MEM_CGROUP_ID_MAX) + return -ENOSPC; return 0; } @@ -4352,10 +4263,7 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css) } spin_unlock(&memcg->event_list_lock); - vmpressure_cleanup(&memcg->vmpressure); - memcg_offline_kmem(memcg); - wb_memcg_offline(memcg); } @@ -4376,8 +4284,11 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css) if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_active) static_branch_dec(&memcg_sockets_enabled_key); + vmpressure_cleanup(&memcg->vmpressure); + cancel_work_sync(&memcg->high_work); + mem_cgroup_remove_from_trees(memcg); memcg_free_kmem(memcg); - __mem_cgroup_free(memcg); + mem_cgroup_free(memcg); } /** |