1 files changed, 88 insertions, 0 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 03204044622f..ccec722213a4 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -3781,3 +3781,91 @@ css_get_next(struct cgroup_subsys *ss, int id,
         return ret;
 }
 
+#ifdef CONFIG_CGROUP_DEBUG
+static struct cgroup_subsys_state *debug_create(struct cgroup_subsys *ss,
+                                                   struct cgroup *cont)
+{
+        struct cgroup_subsys_state *css = kzalloc(sizeof(*css), GFP_KERNEL);
+
+        if (!css)
+                return ERR_PTR(-ENOMEM);
+
+        return css;
+}
+
+static void debug_destroy(struct cgroup_subsys *ss, struct cgroup *cont)
+{
+        kfree(cont->subsys[debug_subsys_id]);
+}
+
+static u64 cgroup_refcount_read(struct cgroup *cont, struct cftype *cft)
+{
+        return atomic_read(&cont->count);
+}
+
+static u64 debug_taskcount_read(struct cgroup *cont, struct cftype *cft)
+{
+        return cgroup_task_count(cont);
+}
+
+static u64 current_css_set_read(struct cgroup *cont, struct cftype *cft)
+{
+        return (u64)(unsigned long)current->cgroups;
+}
+
+static u64 current_css_set_refcount_read(struct cgroup *cont,
+                                           struct cftype *cft)
+{
+        u64 count;
+
+        rcu_read_lock();
+        count = atomic_read(&current->cgroups->refcount);
+        rcu_read_unlock();
+        return count;
+}
+
+static u64 releasable_read(struct cgroup *cgrp, struct cftype *cft)
+{
+        return test_bit(CGRP_RELEASABLE, &cgrp->flags);
+}
+
+static struct cftype debug_files[] =  {
+        {
+                .name = "cgroup_refcount",
+                .read_u64 = cgroup_refcount_read,
+        },
+        {
+                .name = "taskcount",
+                .read_u64 = debug_taskcount_read,
+        },
+
+        {
+                .name = "current_css_set",
+                .read_u64 = current_css_set_read,
+        },
+
+        {
+                .name = "current_css_set_refcount",
+                .read_u64 = current_css_set_refcount_read,
+        },
+
+        {
+                .name = "releasable",
+                .read_u64 = releasable_read,
+        },
+};
+
+static int debug_populate(struct cgroup_subsys *ss, struct cgroup *cont)
+{
+        return cgroup_add_files(cont, ss, debug_files,
+                                ARRAY_SIZE(debug_files));
+}
+
+struct cgroup_subsys debug_subsys = {
+        .name = "debug",
+        .create = debug_create,
+        .destroy = debug_destroy,
+        .populate = debug_populate,
+        .subsys_id = debug_subsys_id,
+};
+#endif /* CONFIG_CGROUP_DEBUG */