1 files changed, 58 insertions, 2 deletions

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 7975b20f1fd1..d9773e49a1b4 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -464,6 +464,28 @@ static struct cgroup_subsys_state *cgroup_css(struct cgroup *cgrp,
 }
 
 /**
+ * cgroup_tryget_css - try to get a cgroup's css for the specified subsystem
+ * @cgrp: the cgroup of interest
+ * @ss: the subsystem of interest
+ *
+ * Find and get @cgrp's css assocaited with @ss.  If the css doesn't exist
+ * or is offline, %NULL is returned.
+ */
+static struct cgroup_subsys_state *cgroup_tryget_css(struct cgroup *cgrp,
+						     struct cgroup_subsys *ss)
+{
+	struct cgroup_subsys_state *css;
+
+	rcu_read_lock();
+	css = cgroup_css(cgrp, ss);
+	if (!css || !css_tryget_online(css))
+		css = NULL;
+	rcu_read_unlock();
+
+	return css;
+}
+
+/**
  * cgroup_e_css - obtain a cgroup's effective css for the specified subsystem
  * @cgrp: the cgroup of interest
  * @ss: the subsystem of interest (%NULL returns @cgrp->self)
@@ -3311,11 +3333,40 @@ static int cgroup_stat_show(struct seq_file *seq, void *v)
 	seq_printf(seq, "nr_dying_descendants %d\n",
 		   cgroup->nr_dying_descendants);
 
-	cgroup_stat_show_cputime(seq, "cpu.");
-
 	return 0;
 }
 
+static int __maybe_unused cgroup_extra_stat_show(struct seq_file *seq,
+						 struct cgroup *cgrp, int ssid)
+{
+	struct cgroup_subsys *ss = cgroup_subsys[ssid];
+	struct cgroup_subsys_state *css;
+	int ret;
+
+	if (!ss->css_extra_stat_show)
+		return 0;
+
+	css = cgroup_tryget_css(cgrp, ss);
+	if (!css)
+		return 0;
+
+	ret = ss->css_extra_stat_show(seq, css);
+	css_put(css);
+	return ret;
+}
+
+static int cpu_stat_show(struct seq_file *seq, void *v)
+{
+	struct cgroup *cgrp = seq_css(seq)->cgroup;
+	int ret = 0;
+
+	cgroup_stat_show_cputime(seq);
+#ifdef CONFIG_CGROUP_SCHED
+	ret = cgroup_extra_stat_show(seq, cgrp, cpu_cgrp_id);
+#endif
+	return ret;
+}
+
 static int cgroup_file_open(struct kernfs_open_file *of)
 {
 	struct cftype *cft = of->kn->priv;
@@ -4423,6 +4474,11 @@ static struct cftype cgroup_base_files[] = {
 		.name = "cgroup.stat",
 		.seq_show = cgroup_stat_show,
 	},
+	{
+		.name = "cpu.stat",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = cpu_stat_show,
+	},
 	{ }	/* terminate */
 };