With xenial kernel:
132 125 0:57 /lxc/x1 /sys/fs/cgroup/blkio rw,nosuid,nodev,noexec,relatime - cgroup cgroup rw,blkio,nsroot=/lxc/x1
with xenial-proposed kernel:
134 125 0:59 / /sys/fs/cgroup/blkio rw,nosuid,nodev,noexec,relatime - cgroup cgroup rw,blkio
With xenial kernel:
132 125 0:57 /lxc/x1 /sys/fs/ cgroup/ blkio rw,nosuid, nodev,noexec, relatime - cgroup cgroup rw,blkio, nsroot= /lxc/x1
with xenial-proposed kernel:
134 125 0:59 / /sys/fs/ cgroup/ blkio rw,nosuid, nodev,noexec, relatime - cgroup cgroup rw,blkio