First test with set_elevator command. It works only for single device so far...

tuned/commands/base.py

@@ -15,7 +15,7 @@ class Command(object):
 
 	@property
 	def name(self):
-		return self._desc
+		return self._name
 
 	@property
 	def desc(self):

tuned/commands/command_set_elevator.py

@@ -0,0 +1,39 @@
+import tuned.commands
+import tuned.logs
+import os
+import struct
+
+log = tuned.logs.get()
+
+class SetElevatorCommand(tuned.commands.Command):
+	"""
+	"""
+
+	def __init__(self):
+		"""
+		"""
+		super(self.__class__, self).__init__("set_elevator")
+
+	def execute(self, args):
+		dev = args[0];
+		elevator = args[1]
+		old_args = [dev, ""]
+
+		try:
+			f = open(os.path.join("/sys/block/", dev, "queue/scheduler"), "r")
+			old_args[1] = f.read()
+			f.close()
+		except (OSError,IOError) as e:
+			log.error("Getting elevator of %s error: %s" % (dev, e))
+
+		log.debug("Applying elevator: %s < %s" % (dev, elevator))
+		try:
+			f = open(os.path.join("/sys/block/", dev, "queue/scheduler"), "w")
+			f.write(elevator)
+			f.close()
+		except (OSError,IOError) as e:
+			log.error("Setting elevator on %s error: %s" % (dev, e))
+		return old_args
+
+	def revert(self, args):
+		self.execute(args)

tuned/commands/repository.py

@@ -10,13 +10,13 @@ log = tuned.logs.get()
 class CommandRepository(tuned.patterns.Singleton):
 	def __init__(self):
 		super(self.__class__, self).__init__()
-		self._loader = tuned.utils.PluginLoader("tuned.commands", "command_", tuned.plugins.Command)
+		self._loader = tuned.utils.PluginLoader("tuned.commands", "command_", tuned.commands.Command)
 		self._commands = {}
 
 		storage = tuned.utils.storage.Storage.get_instance()
 		if storage.data.has_key("commands"):
 			for command_name, args in data["sysctl"].iteritems():
-				self._execute(command_name, args)
+				self._revert(command_name, args)
 
 		storage.data["commands"] = {}
 
@@ -35,7 +35,7 @@ class CommandRepository(tuned.patterns.Singleton):
 		# Store the previously set values
 		storage = tuned.utils.storage.Storage.get_instance()
 
-		if not storage.data["commands"].has_key(command_name)
+		if not storage.data["commands"].has_key(command_name):
 			storage.data["commands"][command_name] = previous_args
 			storage.save()
 		else:
@@ -43,6 +43,15 @@ class CommandRepository(tuned.patterns.Singleton):
 			# in a row and show error instead?
 			pass
 
+	def _revert(self, command_name, args):
+		# Load command on-the-fly
+		if not self._commands.has_key(command_name):
+			self._load_command(command_name)
+
+		# Execute command and get the previously set values.
+		log.debug("reverting command %s with args %s" % (command_name, unicode(args)))
+		self._commands[command_name].revert(args)
+
 	def revert(self, command_name):
 		storage = tuned.utils.storage.Storage.get_instance()
 		if not storage.data["commands"].has_key(command_name):
@@ -57,10 +66,10 @@ class CommandRepository(tuned.patterns.Singleton):
 		try:
 			command_cls = self._loader.load(command_name)
 			command_instance = command_cls()
-			self._commands[command_instance.name](command_instance)
+			self._commands[command_instance.name] = command_instance
 			return command_instance
 		except Exception as exception:
-			command_exception = tuned.plugins.exception.LoadCommandException(command_name, exception)
+			command_exception = tuned.commands.exception.LoadCommandException(command_name, exception)
 			raise command_exception
 
 	def delete(self, command_name):

tuned/plugins/plugin_disk.py

@@ -2,6 +2,7 @@ import os, copy
 import tuned.plugins
 import tuned.logs
 import tuned.monitors
+import tuned.commands
 import struct
 
 log = tuned.logs.get()
@@ -136,13 +137,13 @@ class DiskPlugin(tuned.plugins.Plugin):
 		for dev in self.devidle.keys():
 			if self.devidle[dev]["LEVEL"] > 0:
 				os.system("hdparm -S0 -B255 /dev/"+dev+" > /dev/null 2>&1")
-			self._revert_elevator(dev)
+			tuned.commands.get_repository().revert("set_elevator")
 
 	def update_tuning(self):
 		load = self._load_monitor.get_load()
 		for dev, devload in load.iteritems():
-			if not self._elevator_set:
-				self._apply_elevator(dev)
+			if not self._elevator_set and len(self._options["elevator"]) != 0:
+				tuned.commands.get_repository().execute("set_elevator", [dev, self._options["elevator"]])
 
 			self._init_stats(dev)
 			self._update_stats(dev, devload)