Limiting process memory with MaxWorkingSet

Question

MSDN:

public IntPtr MaxWorkingSet { get; set; }

Gets or sets the maximum allowable working set size for the associated process. Property Value: The maximum working set size that is allowed in memory for the process, in bytes.

So, as far as I understand, I can limit amount of memory that can be used by a process. I've tried this, but with no luck..

Some code:

public class A
{
    public void Do()
    {
        List<string> guids = new List<string>();
        do
        {
            guids.Add(Guid.NewGuid().ToString());
            Thread.Sleep(5);
        } while (true);
    }
}


public static class App
{
    public static void Main()
    {
        Process.GetCurrentProcess().MaxWorkingSet = new IntPtr(2097152);
        try
        {
            new A().Do();
        }
        catch (Exception e)
        {

        }
    }
}

I'm expecting OutOfMemory exception after the limit of 2mb is reached, but nothing happens.. If I open Task Manager I can see that the amount of memory my application uses is growing continiously without any limits.

What am I doing wrong? Thanks in advance

Answer 1

No, this doesn't limit the amount of memory used by the process. It's simply a wrapper around SetProcessWorkingSetSize which a) is a recommendation, and b) limits the working set of the process, which is the amount of physical memory (RAM) this process can consume.

It will absolutely not cause an out of memory exception in that process, even if it allocates significantly more than what you set the MaxWorkingSet property to.

There is an alternative to what you're trying to do -- the Win32 Job Object API. There's a managed wrapper for that on Codeplex (http://jobobjectwrapper.codeplex.com/) to which I contributed. It allows you to create a process and limit the amount of memory this process can use.