plugins: added plugin vm to tune virtual memory management

Currently only transparent hugepages settings is supported.

tuned/plugins/plugin_vm.py

@@ -0,0 +1,50 @@
+import base
+from decorators import *
+import tuned.logs
+
+import os
+import struct
+import glob
+
+log = tuned.logs.get()
+
+class VMPlugin(base.Plugin):
+	"""
+	Plugin for tuning memory management.
+	"""
+
+	@classmethod
+	def tunable_devices(self):
+		return ["vm"]
+
+	def _post_init(self):
+		self._dynamic_tuning = False
+
+	@classmethod
+	def _get_default_options(cls):
+		return {
+			"transparent_hugepages" : None,
+		}
+
+	@classmethod
+	def _thp_file(self):
+		return "/sys/kernel/mm/redhat_transparent_hugepage/enabled"
+
+	@command_set("transparent_hugepages")
+	def _set_transparent_hugepages(self, value):
+		if value not in ["always", "never"]:
+			log.warn("Incorrect transparent_hugepages value.")
+			return
+
+		sys_file = VMPlugin._thp_file()
+		if not os.path.exists(sys_file):
+			return
+
+		tuned.utils.commands.write_to_file(sys_file, value)
+
+	@command_get("transparent_hugepages")
+	def _get_transparent_hugepages(self):
+		sys_file = VMPlugin._thp_file()
+		if not os.path.exists(sys_file):
+			return None
+		return tuned.utils.commands.get_active_option(tuned.utils.commands.read_file(sys_file))