sched: Display autogroup names in /proc/sched_debug

Add autogroup name to cfs_rq and tasks information to /proc/sched_debug.
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20110111101257.GF4772@in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sched_autogroup.c

@@ -231,6 +231,11 @@ void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m)
 #ifdef CONFIG_SCHED_DEBUG
 static inline int autogroup_path(struct task_group *tg, char *buf, int buflen)
 {
+	int enabled = ACCESS_ONCE(sysctl_sched_autogroup_enabled);
+
+	if (!enabled || !tg->autogroup)
+		return 0;
+
 	return snprintf(buf, buflen, "%s-%ld", "/autogroup", tg->autogroup->id);
 }
 #endif /* CONFIG_SCHED_DEBUG */

kernel/sched_debug.c

@@ -93,6 +93,9 @@ static char group_path[PATH_MAX];
 
 static char *task_group_path(struct task_group *tg)
 {
+	if (autogroup_path(tg, group_path, PATH_MAX))
+		return group_path;
+
 	/*
 	 * May be NULL if the underlying cgroup isn't fully-created yet
 	 */