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Lock areas of AsyncCommandManager where multiple threads could try to access/update the same static structures simultaneously. 

This is possible where there is more than one scene (multiple copies of the same script engine) and/or more than one script engine being used.
These operations are not thread safe and could be leading to the exceptions/problems seen in http://opensimulator.org/mantis/view.php?id=6651
This also prevents a small race condition where more than one AsyncLSLCmdHandlerThread could be started.
cpu-performance
Justin Clark-Casey (justincc) 2013-05-31 22:50:15 +01:00
parent 00c1586ff8
commit 921ad8704e
1 changed files with 179 additions and 113 deletions
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84
OpenSim/Region/ScriptEngine/Shared/Api/Implementation/AsyncCommandManager.cs
View File

@ -52,6 +52,15 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
private static Thread cmdHandlerThread;
private static int cmdHandlerThreadCycleSleepms;
/// <summary>
/// Lock for reading/writing static components of AsyncCommandManager.
/// </summary>
/// <remarks>
/// This lock exists so that multiple threads from different engines and/or different copies of the same engine
/// are prevented from running non-thread safe code (e.g. read/write of lists) concurrently.
/// </remarks>
private static object staticLock = new object();
private static List<IScene> m_Scenes = new List<IScene>();
private static List<IScriptEngine> m_ScriptEngines =
new List<IScriptEngine>();
@ -74,37 +83,65 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
public Dataserver DataserverPlugin
{
get { return m_Dataserver[m_ScriptEngine]; }
get
{
lock (staticLock)
return m_Dataserver[m_ScriptEngine];
}
}
public Timer TimerPlugin
{
get { return m_Timer[m_ScriptEngine]; }
get
{
lock (staticLock)
return m_Timer[m_ScriptEngine];
}
}
public HttpRequest HttpRequestPlugin
{
get { return m_HttpRequest[m_ScriptEngine]; }
get
{
lock (staticLock)
return m_HttpRequest[m_ScriptEngine];
}
}
public Listener ListenerPlugin
{
get { return m_Listener[m_ScriptEngine]; }
get
{
lock (staticLock)
return m_Listener[m_ScriptEngine];
}
}
public SensorRepeat SensorRepeatPlugin
{
get { return m_SensorRepeat[m_ScriptEngine]; }
get
{
lock (staticLock)
return m_SensorRepeat[m_ScriptEngine];
}
}
public XmlRequest XmlRequestPlugin
{
get { return m_XmlRequest[m_ScriptEngine]; }
get
{
lock (staticLock)
return m_XmlRequest[m_ScriptEngine];
}
}
public IScriptEngine[] ScriptEngines
{
get { return m_ScriptEngines.ToArray(); }
get
{
lock (staticLock)
return m_ScriptEngines.ToArray();
}
}
public AsyncCommandManager(IScriptEngine _ScriptEngine)
@ -112,6 +149,12 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
m_ScriptEngine = _ScriptEngine;
m_Scene = m_ScriptEngine.World;
// If there is more than one scene in the simulator or multiple script engines are used on the same region
// then more than one thread could arrive at this block of code simultaneously. However, it cannot be
// executed concurrently both because concurrent list operations are not thread-safe and because of other
// race conditions such as the later check of cmdHandlerThread == null.
lock (staticLock)
{
if (m_Scenes.Count == 0)
ReadConfig();
@ -136,6 +179,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
StartThread();
}
}
private static void StartThread()
{
@ -197,6 +241,8 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
}
private static void DoOneCmdHandlerPass()
{
lock (staticLock)
{
// Check HttpRequests
m_HttpRequest[m_ScriptEngines[0]].CheckHttpRequests();
@ -219,6 +265,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
m_Dataserver[s].ExpireRequests();
}
}
}
/// <summary>
/// Remove a specific script (and all its pending commands)
@ -229,8 +276,8 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
{
// m_log.DebugFormat("[ASYNC COMMAND MANAGER]: Removing facilities for script {0}", itemID);
// Remove a specific script
lock (staticLock)
{
// Remove dataserver events
m_Dataserver[engine].RemoveEvents(localID, itemID);
@ -256,6 +303,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
// Remove Sensors
m_SensorRepeat[engine].UnSetSenseRepeaterEvents(localID, itemID);
}
}
/// <summary>
/// Get the sensor repeat plugin for this script engine.
@ -263,12 +311,15 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
/// <param name="engine"></param>
/// <returns></returns>
public static SensorRepeat GetSensorRepeatPlugin(IScriptEngine engine)
{
lock (staticLock)
{
if (m_SensorRepeat.ContainsKey(engine))
return m_SensorRepeat[engine];
else
return null;
}
}
/// <summary>
/// Get the dataserver plugin for this script engine.
@ -276,12 +327,15 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
/// <param name="engine"></param>
/// <returns></returns>
public static Dataserver GetDataserverPlugin(IScriptEngine engine)
{
lock (staticLock)
{
if (m_Dataserver.ContainsKey(engine))
return m_Dataserver[engine];
else
return null;
}
}
/// <summary>
/// Get the timer plugin for this script engine.
@ -289,12 +343,15 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
/// <param name="engine"></param>
/// <returns></returns>
public static Timer GetTimerPlugin(IScriptEngine engine)
{
lock (staticLock)
{
if (m_Timer.ContainsKey(engine))
return m_Timer[engine];
else
return null;
}
}
/// <summary>
/// Get the listener plugin for this script engine.
@ -302,17 +359,22 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
/// <param name="engine"></param>
/// <returns></returns>
public static Listener GetListenerPlugin(IScriptEngine engine)
{
lock (staticLock)
{
if (m_Listener.ContainsKey(engine))
return m_Listener[engine];
else
return null;
}
}
public static Object[] GetSerializationData(IScriptEngine engine, UUID itemID)
{
List<Object> data = new List<Object>();
lock (staticLock)
{
Object[] listeners = m_Listener[engine].GetSerializationData(itemID);
if (listeners.Length > 0)
{
@ -336,6 +398,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
data.Add(sensors.Length);
data.AddRange(sensors);
}
}
return data.ToArray();
}
@ -359,6 +422,8 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
idx+=len;
lock (staticLock)
{
switch (type)
{
case "listener":
@ -379,3 +444,4 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
}
}
}
}