cgroups: Cache controller masks and optimize queues.

test/daughter.service

@@ -0,0 +1,7 @@
+[Unit]
+Description=Daughter Service
+
+[Service]
+Slice=parent.slice
+Type=oneshot
+ExecStart=/bin/true

test/parent.slice

@@ -0,0 +1,5 @@
+[Unit]
+Description=Parent Slice
+
+[Slice]
+BlockIOWeight=200

test/son.service

@@ -0,0 +1,8 @@
+[Unit]
+Description=Son Service
+
+[Service]
+Slice=parent.slice
+Type=oneshot
+ExecStart=/bin/true
+CPUShares=100