cgroups: add rc_cgroup_memory_use_hierarchy setting for cgroups v1

etc/rc.conf

@@ -227,6 +227,11 @@ rc_tty_number=12
 # /sys/fs/cgroup in hybrid or legacy mode.
 #rc_controller_cgroups="YES"
 
+# The following setting turns on the memory.use_hierarchy setting in the
+# root memory cgroup for cgroups v1.
+# It must be set to yes in this file if you want this functionality.
+#rc_cggroup_memory_use_hierarchy="NO"
+
 # The following settings allow you to set up values for the cgroups version 1
 # controllers for your services.
 # They can be set in this file;, however, if you do this, the settings

init.d/cgroups.in

@@ -57,6 +57,9 @@ cgroup1_controllers()
 				mkdir "/sys/fs/cgroup/${name}"
 				mount -n -t cgroup -o "${cgroup_opts},${name}" \
 					"${name}" "/sys/fs/cgroup/${name}"
+					yesno "${rc_cgroup_memory_use_hierarchy:-no}" &&
+					[ "${name}" = memory ] &&
+					echo 1 > /sys/fs/cgroup/memory/memory.use_hierarchy
 				;;
 		esac
 	done < /proc/cgroups