_mkfs_dev $LOOP_DEV >> $seqres.full 2>&1
_mount $LOOP_DEV $SCRATCH_MNT || _fail "mount failed"
+drop_io_cgroup=
+grep -q -w io $cgdir/cgroup.subtree_control || drop_io_cgroup=1
+
echo "+io" > $cgdir/cgroup.subtree_control || _fail "subtree control"
# Read and write from a single group.
check_cg $cgdir/$seq-cg $iosize $iosize
check_cg $cgdir/$seq-cg-2 0 0
-echo "-io" > $cgdir/cgroup.subtree_control || _fail "subtree control"
+if [ "$drop_io_cgroup" = 1 ]; then
+ echo "-io" > $cgdir/cgroup.subtree_control || _fail "subtree control"
+fi
# success, all done
status=0