Increase udev monitor buffer size, make it configurable

The udev monitor buffer size was increased to 1MB. Also, a new
configuration option 'udev_buffer_size' can be specified in
/etc/tuned/tuned-main.conf to set a different buffer size.
Values such as '204800', '200KB', '200 KB' (with space) or '1 MB'
are recognized. If no unit is specified, the number is taken as
the number of bytes.

Resolves: rhbz#1442306

Signed-off-by: Ondřej Lysoněk <olysonek@redhat.com>

tuned-main.conf

@@ -29,3 +29,6 @@ reapply_sysctl = 1
 
 # Default priority assigned to instances
 default_instance_priority = 0
+
+# Udev buffer size
+udev_buffer_size = 1MB

tuned/consts.py

@@ -63,6 +63,7 @@ CFG_UPDATE_INTERVAL = "update_interval"
 CFG_RECOMMEND_COMMAND = "recommend_command"
 CFG_REAPPLY_SYSCTL = "reapply_sysctl"
 CFG_DEFAULT_INSTANCE_PRIORITY = "default_instance_priority"
+CFG_UDEV_BUFFER_SIZE = "udev_buffer_size"
 
 # no_daemon mode
 CFG_DEF_DAEMON = True
@@ -78,6 +79,8 @@ CFG_DEF_RECOMMEND_COMMAND = True
 CFG_DEF_REAPPLY_SYSCTL = True
 # default instance priority
 CFG_DEF_DEFAULT_INSTANCE_PRIORITY = 0
+# default pyudev.Monitor buffer size
+CFG_DEF_UDEV_BUFFER_SIZE = 1024 * 1024
 
 PATH_CPU_DMA_LATENCY = "/dev/cpu_dma_latency"
 

tuned/daemon/application.py

@@ -22,7 +22,8 @@ class Application(object):
 		storage_factory = storage.Factory(storage_provider)
 
 		monitors_repository = monitors.Repository()
-		hardware_inventory = hardware.Inventory()
+		udev_buffer_size = config.get_size("udev_buffer_size", consts.CFG_DEF_UDEV_BUFFER_SIZE)
+		hardware_inventory = hardware.Inventory(buffer_size=udev_buffer_size)
 		device_matcher = hardware.DeviceMatcher()
 		device_matcher_udev = hardware.DeviceMatcherUdev()
 		plugin_instance_factory = plugins.instance.Factory()

tuned/hardware/inventory.py

@@ -1,5 +1,6 @@
 import pyudev
 import tuned.logs
+from tuned import consts
 
 __all__ = ["Inventory"]
 
@@ -11,7 +12,7 @@ class Inventory(object):
 	about related hardware events.
 	"""
 
-	def __init__(self, udev_context=None, udev_monitor_cls=None, monitor_observer_factory=None):
+	def __init__(self, udev_context=None, udev_monitor_cls=None, monitor_observer_factory=None, buffer_size=None):
 		if udev_context is not None:
 			self._udev_context = udev_context
 		else:
@@ -20,6 +21,9 @@ class Inventory(object):
 		if udev_monitor_cls is None:
 			udev_monitor_cls = pyudev.Monitor
 		self._udev_monitor = udev_monitor_cls.from_netlink(self._udev_context)
+		if buffer_size is None:
+			buffer_size = consts.CFG_DEF_UDEV_BUFFER_SIZE
+		self._udev_monitor.set_receive_buffer_size(buffer_size)
 
 		if monitor_observer_factory is None:
 			monitor_observer_factory = _MonitorObserverFactory()

tuned/utils/commands.py

@@ -432,3 +432,24 @@ class commands:
 			return terminate.wait(time, False)
 		except:
 			return terminate.wait(time)
+
+	def get_size(self, s):
+		s = str(s).strip().upper()
+		for unit in ["KB", "MB", "GB", ""]:
+			unit_ix = s.rfind(unit)
+			if unit_ix == -1:
+				continue
+			try:
+				val = int(s[:unit_ix])
+				u = s[unit_ix:]
+				if u == "KB":
+					val *= 1024
+				elif u == "MB":
+					val *= 1024 * 1024
+				elif u == "GB":
+					val *= 1024 * 1024 * 1024
+				elif u != "":
+					val = None
+				return val
+			except ValueError:
+				return None

tuned/utils/global_config.py

@@ -47,3 +47,14 @@ class GlobalConfig():
 
 	def set(self, key, value):
 		self._cfg[key] = value
+
+	def get_size(self, key, default = None):
+		val = self.get(key)
+		if val is None:
+			return default
+		ret = self._cmd.get_size(val)
+		if ret is None:
+			log.error("Error parsing value '%s', using '%s'." %(val, default))
+			return default
+		else:
+			return ret