Merge branch 'for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

[platform/adaptation/renesas_rcar/renesas_kernel.git] / mm / memcontrol.c

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index b8dc8e4..0f1d921 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3321,52 +3321,53 @@ void mem_cgroup_destroy_cache(struct kmem_cache *cachep)
        schedule_work(&cachep->memcg_params->destroy);
 }
 
-static char *memcg_cache_name(struct mem_cgroup *memcg, struct kmem_cache *s)
-{
-       char *name;
-       struct dentry *dentry;
-
-       rcu_read_lock();
-       dentry = rcu_dereference(memcg->css.cgroup->dentry);
-       rcu_read_unlock();
-
-       BUG_ON(dentry == NULL);
-
-       name = kasprintf(GFP_KERNEL, "%s(%d:%s)", s->name,
-                        memcg_cache_id(memcg), dentry->d_name.name);
-
-       return name;
-}
+/*
+ * This lock protects updaters, not readers. We want readers to be as fast as
+ * they can, and they will either see NULL or a valid cache value. Our model
+ * allow them to see NULL, in which case the root memcg will be selected.
+ *
+ * We need this lock because multiple allocations to the same cache from a non
+ * will span more than one worker. Only one of them can create the cache.
+ */
+static DEFINE_MUTEX(memcg_cache_mutex);
 
+/*
+ * Called with memcg_cache_mutex held
+ */
 static struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg,
                                         struct kmem_cache *s)
 {
-       char *name;
        struct kmem_cache *new;
+       static char *tmp_name = NULL;
 
-       name = memcg_cache_name(memcg, s);
-       if (!name)
-               return NULL;
+       lockdep_assert_held(&memcg_cache_mutex);
+
+       /*
+        * kmem_cache_create_memcg duplicates the given name and
+        * cgroup_name for this name requires RCU context.
+        * This static temporary buffer is used to prevent from
+        * pointless shortliving allocation.
+        */
+       if (!tmp_name) {
+               tmp_name = kmalloc(PATH_MAX, GFP_KERNEL);
+               if (!tmp_name)
+                       return NULL;
+       }
+
+       rcu_read_lock();
+       snprintf(tmp_name, PATH_MAX, "%s(%d:%s)", s->name,
+                        memcg_cache_id(memcg), cgroup_name(memcg->css.cgroup));
+       rcu_read_unlock();
 
-       new = kmem_cache_create_memcg(memcg, name, s->object_size, s->align,
+       new = kmem_cache_create_memcg(memcg, tmp_name, s->object_size, s->align,
                                      (s->flags & ~SLAB_PANIC), s->ctor, s);
 
        if (new)
                new->allocflags |= __GFP_KMEMCG;
 
-       kfree(name);
        return new;
 }
 
-/*
- * This lock protects updaters, not readers. We want readers to be as fast as
- * they can, and they will either see NULL or a valid cache value. Our model
- * allow them to see NULL, in which case the root memcg will be selected.
- *
- * We need this lock because multiple allocations to the same cache from a non
- * will span more than one worker. Only one of them can create the cache.
- */
-static DEFINE_MUTEX(memcg_cache_mutex);
 static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
                                                  struct kmem_cache *cachep)
 {
@@ -5912,6 +5913,7 @@ static struct cftype mem_cgroup_files[] = {
        },
        {
                .name = "use_hierarchy",
+               .flags = CFTYPE_INSANE,
                .write_u64 = mem_cgroup_hierarchy_write,
                .read_u64 = mem_cgroup_hierarchy_read,
        },
@@ -6907,6 +6909,21 @@ static void mem_cgroup_move_task(struct cgroup *cont,
 }
 #endif
 
+/*
+ * Cgroup retains root cgroups across [un]mount cycles making it necessary
+ * to verify sane_behavior flag on each mount attempt.
+ */
+static void mem_cgroup_bind(struct cgroup *root)
+{
+       /*
+        * use_hierarchy is forced with sane_behavior.  cgroup core
+        * guarantees that @root doesn't have any children, so turning it
+        * on for the root memcg is enough.
+        */
+       if (cgroup_sane_behavior(root))
+               mem_cgroup_from_cont(root)->use_hierarchy = true;
+}
+
 struct cgroup_subsys mem_cgroup_subsys = {
        .name = "memory",
        .subsys_id = mem_cgroup_subsys_id,
@@ -6917,6 +6934,7 @@ struct cgroup_subsys mem_cgroup_subsys = {
        .can_attach = mem_cgroup_can_attach,
        .cancel_attach = mem_cgroup_cancel_attach,
        .attach = mem_cgroup_move_task,
+       .bind = mem_cgroup_bind,
        .base_cftypes = mem_cgroup_files,
        .early_init = 0,
        .use_id = 1,