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-rw-r--r--mm/memcontrol.c75
1 files changed, 55 insertions, 20 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index caea25a21c70..089ef3614155 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2273,20 +2273,30 @@ static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
current->memcg_kmem_skip_account = 0;
}
-/*
+static inline bool memcg_kmem_bypass(void)
+{
+ if (in_interrupt() || !current->mm || (current->flags & PF_KTHREAD))
+ return true;
+ return false;
+}
+
+/**
+ * memcg_kmem_get_cache: select the correct per-memcg cache for allocation
+ * @cachep: the original global kmem cache
+ *
* Return the kmem_cache we're supposed to use for a slab allocation.
* We try to use the current memcg's version of the cache.
*
- * If the cache does not exist yet, if we are the first user of it,
- * we either create it immediately, if possible, or create it asynchronously
- * in a workqueue.
- * In the latter case, we will let the current allocation go through with
- * the original cache.
+ * If the cache does not exist yet, if we are the first user of it, we
+ * create it asynchronously in a workqueue and let the current allocation
+ * go through with the original cache.
*
- * Can't be called in interrupt context or from kernel threads.
- * This function needs to be called with rcu_read_lock() held.
+ * This function takes a reference to the cache it returns to assure it
+ * won't get destroyed while we are working with it. Once the caller is
+ * done with it, memcg_kmem_put_cache() must be called to release the
+ * reference.
*/
-struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
+struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep)
{
struct mem_cgroup *memcg;
struct kmem_cache *memcg_cachep;
@@ -2294,10 +2304,7 @@ struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
VM_BUG_ON(!is_root_cache(cachep));
- if (cachep->flags & SLAB_ACCOUNT)
- gfp |= __GFP_ACCOUNT;
-
- if (!(gfp & __GFP_ACCOUNT))
+ if (memcg_kmem_bypass())
return cachep;
if (current->memcg_kmem_skip_account)
@@ -2330,14 +2337,27 @@ out:
return cachep;
}
-void __memcg_kmem_put_cache(struct kmem_cache *cachep)
+/**
+ * memcg_kmem_put_cache: drop reference taken by memcg_kmem_get_cache
+ * @cachep: the cache returned by memcg_kmem_get_cache
+ */
+void memcg_kmem_put_cache(struct kmem_cache *cachep)
{
if (!is_root_cache(cachep))
css_put(&cachep->memcg_params.memcg->css);
}
-int __memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
- struct mem_cgroup *memcg)
+/**
+ * memcg_kmem_charge: charge a kmem page
+ * @page: page to charge
+ * @gfp: reclaim mode
+ * @order: allocation order
+ * @memcg: memory cgroup to charge
+ *
+ * Returns 0 on success, an error code on failure.
+ */
+int memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
+ struct mem_cgroup *memcg)
{
unsigned int nr_pages = 1 << order;
struct page_counter *counter;
@@ -2358,19 +2378,34 @@ int __memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
return 0;
}
-int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
+/**
+ * memcg_kmem_charge: 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(struct page *page, gfp_t gfp, int order)
{
struct mem_cgroup *memcg;
int ret = 0;
+ if (memcg_kmem_bypass())
+ return 0;
+
memcg = get_mem_cgroup_from_mm(current->mm);
if (!mem_cgroup_is_root(memcg))
- ret = __memcg_kmem_charge_memcg(page, gfp, order, memcg);
+ ret = memcg_kmem_charge_memcg(page, gfp, order, memcg);
css_put(&memcg->css);
return ret;
}
-
-void __memcg_kmem_uncharge(struct page *page, int order)
+/**
+ * memcg_kmem_uncharge: uncharge a kmem page
+ * @page: page to uncharge
+ * @order: allocation order
+ */
+void memcg_kmem_uncharge(struct page *page, int order)
{
struct mem_cgroup *memcg = page->mem_cgroup;
unsigned int nr_pages = 1 << order;