From 0510c473d4cd9097401e3a7bc236b0121977b81d Mon Sep 17 00:00:00 2001
From: William Hubbs <williamh@gentoo.org>
Date: Fri, 18 Nov 2011 15:54:18 -0600
Subject: [PATCH] CGroups: /sys/fs/cgroups should be a tmpfs

The kernel documentation states that a cgroup file system should not be
mounted here, but a tmpfs.

This also means that we should not create a group for each process, but
we should allow the user to specify which group a process should be
assigned to. The rc_cgroup variable will be used for this purpose.

For more information, see /usr/src/linux/Documentation/cgroups/cgroups.txt.
---
 init.d/sysfs.in    |  2 +-
 sh/runscript.sh.in | 29 +++++++----------------------
 2 files changed, 8 insertions(+), 23 deletions(-)

diff --git a/init.d/sysfs.in b/init.d/sysfs.in
index 257f3148..a536d5fd 100644
--- a/init.d/sysfs.in
+++ b/init.d/sysfs.in
@@ -65,7 +65,7 @@ mount_misc()
 	if [ -d /sys/fs/cgroup ] && ! mountinfo -q /sys/fs/cgroup; then
 		if grep -qs cgroup /proc/filesystems; then
 			ebegin "Mounting cgroup filesystem"
-			mount -n -t cgroup -o  nodev,noexec,nosuid \
+			mount -n -t tmpfs -o  nodev,noexec,nosuid \
 				cgroup /sys/fs/cgroup
 			eend $?
 		fi
diff --git a/sh/runscript.sh.in b/sh/runscript.sh.in
index c7d712be..706a1f7d 100644
--- a/sh/runscript.sh.in
+++ b/sh/runscript.sh.in
@@ -190,18 +190,13 @@ fi
 sourcex -e "@SYSCONFDIR@/rc.conf"
 
 # Attach to CGroup - dir existing is enough for us
-if [ -d /sys/fs/cgroup/ ]; then
-	# use RC_SVCNAME unless overridden in conf.d
-	SVC_CGROUP=${rc_cgroup:-$RC_SVCNAME}
-	mkdir -p /sys/fs/cgroup/${SVC_CGROUP}
-	for f in cpuset.cpus cpuset.mems; do
-		if [ -f /sys/fs/cgroup/${f} ]; then
-			cp /sys/fs/cgroup/${f} /sys/fs/cgroup/${SVC_CGROUP}
-		fi
-	done
-	# now attach self to cgroup - any children of this process will inherit this
-	echo $$ > /sys/fs/cgroup/${SVC_CGROUP}/tasks
-	# TODO: set res limits from conf.d
+if [ -d /sys/fs/cgroup -a -n "${rc_cgroup}" ]; then
+	if [ -d /sys/fs/cgroup/${rc_cgroup} ]; then
+		# attach self to cgroup - any children of this process will inherit this
+		echo $$ > /sys/fs/cgroup/${rc_cgroup}/tasks
+	else
+		eerror "Control group /sys/fs/cgroup/${rc_cgroup} does not exist."
+	fi
 fi
 
 # Apply any ulimit defined
@@ -307,14 +302,4 @@ while [ -n "$1" ]; do
 	exit 1
 done
 
-# CGroup cleanup
-if [ -d /sys/fs/cgroup/ ]; then
-	# use RC_SVCNAME unless overridden in conf.d
-	SVC_CGROUP=${rc_cgroup:-$RC_SVCNAME}
-	# reattach to root cgroup
-	echo $$ > /sys/fs/cgroup/tasks
-	# remove cgroup if empty, will fail if any task attached
-	rmdir  /sys/fs/cgroup/${SVC_CGROUP} 2>/dev/null
-fi
-
 exit 0