From b6c3006d204a0b86e1ebe02ca38f9f071a03c7ef Mon Sep 17 00:00:00 2001
From: Paul Menage <menage@google.com>
Date: Thu, 10 Apr 2008 21:29:16 -0700
Subject: [PATCH] cgroups: include hierarchy ids in /proc/<pid>/cgroup

Extend the /proc/<pid>/cgroup file to include the appropriate hierarchy ID on
each line.

Currently this ID isn't really needed since a hierarchy can be completely
identified by the set of subsystems bound to it, but this is likely to change
in the near future in order to support stateless subsystems and
merging/rebinding of subsystems.  Getting this change into 2.6.25 reduces the
need for an API change later.

Signed-off-by: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 kernel/cgroup.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 62f1a5231fe9..2727f9238359 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2569,6 +2569,7 @@ static int proc_cgroup_show(struct seq_file *m, void *v)
 		/* Skip this hierarchy if it has no active subsystems */
 		if (!root->actual_subsys_bits)
 			continue;
+		seq_printf(m, "%lu:", root->subsys_bits);
 		for_each_subsys(root, ss)
 			seq_printf(m, "%s%s", count++ ? "," : "", ss->name);
 		seq_putc(m, ':');