diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index a3869bf97746917fd439ce0e28a4893c8f12abc1..27123e597eca0296361cec929eb86e4c169453d9 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -181,9 +181,6 @@ struct mem_cgroup {
/* vmpressure notifications */
struct vmpressure vmpressure;
- /* css_online() has been completed */
- int initialized;
-
/*
* Should the accounting and control be hierarchical, per subtree?
*/
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6937f16f5ecb3417d9e544727ba430c33ce3b8c1..f6bc78f4ed137bd4fd3b46b439170b6ebc485bd0 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);
}
/**