}
#ifdef CONFIG_MEMCG_KMEM
+extern spinlock_t css_set_lock;
+
+static void obj_cgroup_release(struct percpu_ref *ref)
+{
+ struct obj_cgroup *objcg = container_of(ref, struct obj_cgroup, refcnt);
+ struct mem_cgroup *memcg;
+ unsigned int nr_bytes;
+ unsigned int nr_pages;
+ unsigned long flags;
+
+ /*
+ * 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;
+
+ spin_lock_irqsave(&css_set_lock, flags);
+ memcg = obj_cgroup_memcg(objcg);
+ if (nr_pages)
+ __memcg_kmem_uncharge(memcg, nr_pages);
+ list_del(&objcg->list);
+ mem_cgroup_put(memcg);
+ spin_unlock_irqrestore(&css_set_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(&css_set_lock);
+
+ /* Move active objcg to the parent's list */
+ xchg(&objcg->memcg, parent);
+ css_get(&parent->css);
+ list_add(&objcg->list, &parent->objcg_list);
+
+ /* Move already reparented objcgs to the parent's list */
+ list_for_each_entry(iter, &memcg->objcg_list, list) {
+ css_get(&parent->css);
+ xchg(&iter->memcg, parent);
+ css_put(&memcg->css);
+ }
+ list_splice(&memcg->objcg_list, &parent->objcg_list);
+
+ spin_unlock_irq(&css_set_lock);
+
+ percpu_ref_kill(&objcg->refcnt);
+}
+
/*
* This will be the memcg's index in each cache's ->memcg_params.memcg_caches.
* The main reason for not using cgroup id for this:
unsigned long ino = 0;
rcu_read_lock();
- if (PageSlab(page) && !PageTail(page))
+ if (PageSlab(page) && !PageTail(page)) {
memcg = memcg_from_slab_page(page);
- else
- memcg = READ_ONCE(page->mem_cgroup);
+ } else {
+ memcg = page->mem_cgroup;
+
+ /*
+ * The lowest bit set means that memcg isn't a valid
+ * memcg pointer, but a obj_cgroups pointer.
+ * In this case the page is shared and doesn't belong
+ * to any specific memory cgroup.
+ */
+ if ((unsigned long) memcg & 0x1UL)
+ memcg = NULL;
+ }
+
while (memcg && !(memcg->css.flags & CSS_ONLINE))
memcg = parent_mem_cgroup(memcg);
if (memcg)
struct memcg_stock_pcp {
struct mem_cgroup *cached; /* this never be root cgroup */
unsigned int nr_pages;
+
+#ifdef CONFIG_MEMCG_KMEM
+ struct obj_cgroup *cached_objcg;
+ unsigned int nr_bytes;
+#endif
+
struct work_struct work;
unsigned long flags;
#define FLUSHING_CACHED_CHARGE 0
static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
static DEFINE_MUTEX(percpu_charge_mutex);
+#ifdef CONFIG_MEMCG_KMEM
+static void drain_obj_stock(struct memcg_stock_pcp *stock);
+static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
+ struct mem_cgroup *root_memcg);
+
+#else
+static inline void drain_obj_stock(struct memcg_stock_pcp *stock)
+{
+}
+static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
+ struct mem_cgroup *root_memcg)
+{
+ return false;
+}
+#endif
+
/**
* consume_stock: Try to consume stocked charge on this cpu.
* @memcg: memcg to consume from.
local_irq_save(flags);
stock = this_cpu_ptr(&memcg_stock);
+ drain_obj_stock(stock);
drain_stock(stock);
clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
if (memcg && stock->nr_pages &&
mem_cgroup_is_descendant(memcg, root_memcg))
flush = true;
+ if (obj_stock_flush_required(stock, root_memcg))
+ flush = true;
rcu_read_unlock();
if (flush &&
return page->mem_cgroup;
}
+__always_inline struct obj_cgroup *get_obj_cgroup_from_current(void)
+{
+ struct obj_cgroup *objcg = NULL;
+ struct mem_cgroup *memcg;
+
+ if (unlikely(!current->mm && !current->active_memcg))
+ return NULL;
+
+ rcu_read_lock();
+ if (unlikely(current->active_memcg))
+ memcg = rcu_dereference(current->active_memcg);
+ else
+ memcg = mem_cgroup_from_task(current);
+
+ for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) {
+ objcg = rcu_dereference(memcg->objcg);
+ if (objcg && obj_cgroup_tryget(objcg))
+ break;
+ }
+ rcu_read_unlock();
+
+ return objcg;
+}
+
static int memcg_alloc_cache_id(void)
{
int id, size;
if (PageKmemcg(page))
__ClearPageKmemcg(page);
}
+
+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_irq_save(flags);
+
+ stock = this_cpu_ptr(&memcg_stock);
+ if (objcg == stock->cached_objcg && stock->nr_bytes >= nr_bytes) {
+ stock->nr_bytes -= nr_bytes;
+ ret = true;
+ }
+
+ local_irq_restore(flags);
+
+ return ret;
+}
+
+static void drain_obj_stock(struct memcg_stock_pcp *stock)
+{
+ struct obj_cgroup *old = stock->cached_objcg;
+
+ if (!old)
+ return;
+
+ if (stock->nr_bytes) {
+ unsigned int nr_pages = stock->nr_bytes >> PAGE_SHIFT;
+ unsigned int nr_bytes = stock->nr_bytes & (PAGE_SIZE - 1);
+
+ if (nr_pages) {
+ rcu_read_lock();
+ __memcg_kmem_uncharge(obj_cgroup_memcg(old), nr_pages);
+ rcu_read_unlock();
+ }
+
+ /*
+ * 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;
+ }
+
+ obj_cgroup_put(old);
+ stock->cached_objcg = NULL;
+}
+
+static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
+ struct mem_cgroup *root_memcg)
+{
+ struct mem_cgroup *memcg;
+
+ if (stock->cached_objcg) {
+ memcg = obj_cgroup_memcg(stock->cached_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)
+{
+ struct memcg_stock_pcp *stock;
+ unsigned long flags;
+
+ local_irq_save(flags);
+
+ stock = this_cpu_ptr(&memcg_stock);
+ if (stock->cached_objcg != objcg) { /* reset if necessary */
+ drain_obj_stock(stock);
+ obj_cgroup_get(objcg);
+ stock->cached_objcg = objcg;
+ stock->nr_bytes = atomic_xchg(&objcg->nr_charged_bytes, 0);
+ }
+ stock->nr_bytes += nr_bytes;
+
+ if (stock->nr_bytes > PAGE_SIZE)
+ drain_obj_stock(stock);
+
+ local_irq_restore(flags);
+}
+
+int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size)
+{
+ struct mem_cgroup *memcg;
+ unsigned int nr_pages, nr_bytes;
+ int ret;
+
+ if (consume_obj_stock(objcg, size))
+ return 0;
+
+ /*
+ * In theory, memcg->nr_charged_bytes can have enough
+ * pre-charged bytes to satisfy the allocation. However,
+ * flushing memcg->nr_charged_bytes requires two atomic
+ * operations, and memcg->nr_charged_bytes can't be big,
+ * so it's better to ignore it and try grab some new pages.
+ * memcg->nr_charged_bytes will be flushed in
+ * refill_obj_stock(), called from this function or
+ * independently later.
+ */
+ rcu_read_lock();
+ memcg = obj_cgroup_memcg(objcg);
+ css_get(&memcg->css);
+ rcu_read_unlock();
+
+ nr_pages = size >> PAGE_SHIFT;
+ nr_bytes = size & (PAGE_SIZE - 1);
+
+ if (nr_bytes)
+ nr_pages += 1;
+
+ ret = __memcg_kmem_charge(memcg, gfp, nr_pages);
+ if (!ret && nr_bytes)
+ refill_obj_stock(objcg, PAGE_SIZE - nr_bytes);
+
+ css_put(&memcg->css);
+ return ret;
+}
+
+void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size)
+{
+ refill_obj_stock(objcg, size);
+}
+
#endif /* CONFIG_MEMCG_KMEM */
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#ifdef CONFIG_MEMCG_KMEM
static int memcg_online_kmem(struct mem_cgroup *memcg)
{
+ struct obj_cgroup *objcg;
int memcg_id;
if (cgroup_memory_nokmem)
if (memcg_id < 0)
return memcg_id;
+ objcg = obj_cgroup_alloc();
+ if (!objcg) {
+ memcg_free_cache_id(memcg_id);
+ return -ENOMEM;
+ }
+ objcg->memcg = memcg;
+ rcu_assign_pointer(memcg->objcg, objcg);
+
static_branch_enable(&memcg_kmem_enabled_key);
/*
parent = root_mem_cgroup;
/*
- * Deactivate and reparent kmem_caches.
+ * Deactivate and reparent kmem_caches and objcgs.
*/
memcg_deactivate_kmem_caches(memcg, parent);
+ memcg_reparent_objcgs(memcg, parent);
kmemcg_id = memcg->kmemcg_id;
BUG_ON(kmemcg_id < 0);
memcg->socket_pressure = jiffies;
#ifdef CONFIG_MEMCG_KMEM
memcg->kmemcg_id = -1;
+ INIT_LIST_HEAD(&memcg->objcg_list);
#endif
#ifdef CONFIG_CGROUP_WRITEBACK
INIT_LIST_HEAD(&memcg->cgwb_list);
projects / linux-2.6-microblaze.git / blobdiff