C＃托管Powershell中的内存泄漏

Question

i have a simple app, that's creating a Powershell runspace:

        var iis = InitialSessionState.CreateDefault();
        iis.ExecutionPolicy = ExecutionPolicy.Unrestricted;
        iis.LanguageMode = PSLanguageMode.FullLanguage;
        iis.ThreadOptions = PSThreadOptions.UseNewThread;
        iis.DisableFormatUpdates = true;

        m_Settings = new PSInvocationSettings
        {
            Host = new PSHostProxy(new PSUIStub()),
        };

        m_RunspacePool = RunspaceFactory.CreateRunspacePool(iis);
        m_RunspacePool.CleanupInterval = new TimeSpan(0, 0, 10);
        m_RunspacePool.SetMaxRunspaces(1);
        m_RunspacePool.SetMinRunspaces(1);
        m_RunspacePool.Open();

And then uses it to execute several PowerShell scripts. Each RUN is invoked by external event (runs in another thread) and happens ussualy with 20-50 seconds after the foregoing RUN:

RUN:
{
  foreach(var scriptName in scripts)
  {
    var ps = PowerShell.Create();
    ps.RunspacePool = m_RunspacePool;
    var input = new PSDataCollection<string>();

    ps.AddCommand(Path.Combine(scriptPath, scriptName));
    ps.AddArgument(args);

    // Call
    ps.Invoke(input, m_Output, m_Settings);
    ...
    m_Output.Clear();
    input.Clear();
    input.Dispose();

    ps.Dispose();
    ps = null;
  }
}

And memory usage of this keeps raising during the run, although the scripts are always the same and even their results are the same. Each cycle creates a bunch (well like thousands of them, but i suppose the number is given by length of the executed scripts...) of SessionStateCmdLetEntry and those are never disposed and GCed, because of reference by a TimerCallback created by RunspacePoolInternal. This can take up to 1GB of memory per day...

Does anyone have tips, what else should I dispose or clear to avoid stashing the SessionStateCmdLetEntries? Or any workarounds for this?

I just need a long running process, that invokes several Powershell scripts and does not eat up memory.. I've also tried not reusing the RunSpacePool and creating a new Runspace for each RUN and even for each script, but it did not help at all...

Thanks for any help...

Answer 1

It shows out, that the leak is not caused by the C# code, but by a PowerShell script run through this. The script creates its own RunspacePool and PowerShell instance to execute some specific code and this causes the memory leak.