Hi,
If I got that right, it's ok for the maintainer of ulatencyd, if the
subsystems were mounted into it's own subdirectories?
If so, I like to propose an intitv script which does it.
When reading the introduction to cgroup in the kernel documentation, it
is best pratice to mount tmpfs under /sys/fs/cgroup and create a
subdirectory for every subsystem.
Please see attachement for the script. CGROUPSUBSYSTEMS must be set to
yes in /etc/default/tmpfs. So cgroup subsystems are not mounted by
default, which does not break existent configurations done via
/etc/fstab and one can switch it on/off easily.
The script was tested on Squeeze with 2.6.39-bpo60-2. Activated with
"update-rc.d mountcgroupsubsys.sh defaults".
Problem: It is very cgroup specific and is possibily misplaced in
initscripts?
Regards,
Marcus
#! /bin/sh
### BEGIN INIT INFO
# Provides: mountcgroupsubsys
# Required-Start: mountkernfs
# Required-Stop:
# Should-Start:
# Default-Start: S
# Default-Stop:
# Short-Description: Mount cgroup subsystems
# Description: Mounts every cgroup subsystem
# in it's own directory under /sys/fs/cgroup
### END INIT INFO
PATH=/sbin:/bin
. /lib/init/vars.sh
. /lib/lsb/init-functions
. /lib/init/mount-functions.sh
[ -f /etc/default/tmpfs ] && . /etc/default/tmpfs
do_start () {
#
# Mount cgroup on /sys/fs/cgroup
#
# Only mount cgroup if it is supported and enabled in /etc/default/tmpfs
if grep -E -qs "cgroup\$" /proc/filesystems && [ -d /sys/fs/cgroup ] &&
[ yes = "$CGROUPSUBSYSTEMS" ]
then
RW_OPT=
[ "${RW_SIZE:=$TMPFS_SIZE}" ] && RW_OPT=",size=$RW_SIZE"
domount tmpfs "" /sys/fs/cgroup tmpfs -omode=0755,nosuid$RW_OPT
CGROUP_EXCL_SUBSYS=${CGROUP_EXCL_SUBSYS:-"#"}
grep -i -o '^[a-z_-]*' /proc/cgroups | grep -v
${CGROUP_EXCL_SUBSYS} | while read subsys; do
if [ ! -d /sys/fs/cgroup/${subsys} ]
then
mkdir /sys/fs/cgroup/${subsys}
domount cgroup "" /sys/fs/cgroup/${subsys}
cgroup -o${subsys}
[ $? -eq 0 ] && log_success_msg "Successfully
mounted /sys/fs/cgroup/${subsys}."
else
log_warning_msg "Directory
/sys/fs/cgroup/${subsys} does already exists. Do not try to mount cgroup
subsystem."
fi
done
else
log_warning_msg "Cgroups not supported by kernel or
CGROUPSUBSYSTEMS not set to 'yes' in /etc/default/tmpfs."
fi
}
do_stop () {
if [ -d /sys/fs/cgroup ]
then
for subsys in $(grep -i -o '^[a-z_-]*' /proc/cgroups); do
if [ -d /sys/fs/cgroup/${subsys} ]
then
umount /sys/fs/cgroup/${subsys}
[ $? -ne 0 ] && log_warning_msg "Could not
unmount /sys/fs/cgroup/${subsys}."
rmdir /sys/fs/cgroup/${subsys}
[ $? -eq 0] && log_success_msg "Successfully
removed /sys/fs/cgroup/${subsys}."
fi
done
grep "/sys/fs/cgroup" /etc/mtab > /dev/null
if [ $? -eq 0 ]
then
umount /sys/fs/cgroup
[ $? -eq 0 ] && log_success_msg "Successfully unmounted
/sys/fs/cgroup."
fi
else
log_warning_msg "Directory /sys/fs/cgroup not found. Do not try
to unmount cgroup subsystems."
fi
}
case "$1" in
"")
echo "Warning: mountcgroupsubsys should be called with the 'start'
argument." >&2
do_start
;;
start)
do_start
;;
restart|reload|force-reload)
echo "Error: argument '$1' not supported" >&2
exit 3
;;
stop)
do_stop
;;
*)
echo "Usage: mountcgroupsubsys [start|stop]" >&2
exit 3
;;
esac
