Memory leak again

01-20-2008 11:58 PM |

 I found 2 memory leak case:

1. I created a page which loads and unloads a dynamic resource, when I refresh the page, the memory increase about 7Mb

Please download source code here : http://rapidshare.com/files/85335888/TestContext.zip and give me an advice if you can

2. I create a page which loads and unloads many custom controls, and the memory doesn't decrease when the page unloads the custom control

 Please download source code here : http://rapidshare.com/files/85335555/TestContext.rar and give me an advice if you can

PS: You can use Windows Task Manager to  monitor the usage memory of the SilverLight page

Thanks for any reply! 

Re: Memory leak again

01-23-2008 1:21 AM |

Thank you so much 

Re: Memory leak again

01-23-2008 10:31 PM |

How about this case. It seems the memory leak  

 String script = "<Canvas><Image Source=\"bg.jpg\"/></Canvas>";
            Object objApp = XamlReader.Load(script);
            Canvas c = objApp as Canvas;
            for (int i = c.Children.Count - 1; i >= 0; i--)
            {
                Image img = c.Children[ i ] as Image;
                try
                {
                    c.Children.RemoveAt(i);
                    this.Children.Add(img);
                }
                catch (Exception exception)
                {
                    System.Diagnostics.Debug.WriteLine(exception.Message);
                }
            }

            c.Children.Clear();

Re: Memory leak again

01-23-2008 10:40 PM |

haughtycool:

Thank you so much

How come your heart is broken? :P 

Re: Memory leak again

01-24-2008 3:07 AM |

haughtycool:

How about this case. It seems the memory leak  

 String script = "<Canvas><Image Source=\"bg.jpg\"/></Canvas>";
            Object objApp = XamlReader.Load(script);
            Canvas c = objApp as Canvas;
            for (int i = c.Children.Count - 1; i >= 0; i--)
            {
                Image img = c.Children[ i ] as Image;
                try
                {
                    c.Children.RemoveAt(i);
                    this.Children.Add(img);
                }
                catch (Exception exception)
                {
                    System.Diagnostics.Debug.WriteLine(exception.Message);
                }
            }

            c.Children.Clear();

No, I don't think so, GC works fine in that case, I've tested it and there was no memory leak...

could you tell me why you think there is memory leak in that case?

Re: Re: Memory leak again

01-24-2008 3:23 AM |

Yes, when I refresh the page, the memory increases about 7Mb 

Re: Re: Memory leak again

01-24-2008 3:53 AM |

are you using GC.GetTotalMemory(true) or you're using task manager?

GC.GetTotalMemory returns best available approximation of the number of bytes currently allocated in managed memory. I've tested your case with GC and there was no memory leak on managed code...

but if you're using the task manager, you may see some memory leaks after reloading page continuously; unfortunately, most memory leaks are directly related to the IE garbage collector.

Re: Re: Re: Memory leak again

01-24-2008 4:08 AM |

Maybe you're right. If I repair the source code as follow, the memory of IE doesn't increase

String script = "<Canvas><Image Source=\"bg.jpg\"/></Canvas>";
            Object objApp = XamlReader.Load(script);
            Canvas c = objApp as Canvas;
           this.Children.Add(c);
            for (int i = c.Children.Count - 1; i >= 0; i--)
            {
                Image img = c.Children[ i ] as Image;
                try
                {
                    c.Children.RemoveAt(i);
                    this.Children.Add(img);
                }
                catch (Exception exception)
                {
                    System.Diagnostics.Debug.WriteLine(exception.Message);
                }
            }

            c.Children.Clear();

Re: Re: Re: Memory leak again

01-24-2008 4:35 AM |

Hmmm, I didn't see your code completely and I thought you're removing parent canvas...

I think the problem returns to the silverlight plug-in cos at the end you're calling c.Children.Clear()  and in the for statement you're just adding childs so the parent canvas remains in memory(objApp and c pointers) and loaded to the temporary xaml object tree, but if you set c and objApp to null at the end of method, there will be no memory leak so far.(it could be the reason why we see no leak in managed code)

I believe these object which is loaded by XamlReader and are no longer available causes the memory leak...

Re: Re: Re: Re: Memory leak again

01-24-2008 5:14 AM |

However when I add the statement this.Children.Remove(c); at the end of code block, the memory increases when I refresh the page. Is this funny 

Thank you. Our discussion is very interesting. 

Re: Re: Re: Re: Memory leak again

01-24-2008 5:25 AM |

haughtycool:

However when I add the statement this.Children.Remove(c); at the end of code block, the memory increases when I refresh the page. Is this funny 

Idon't know but if your code is something like :

String script = "<Canvas><Image Source=\"bg.jpg\"/></Canvas>";
            Object objApp = XamlReader.Load(script);
            Canvas c = objApp as Canvas;
           for (int i = c.Children.Count - 1; i >= 0; i--)
            {
                Image img = c.Children[ i ] as Image;
                try
                {
                    c.Children.RemoveAt(i);
                    this.Children.Add(img);
                }
                catch (Exception exception)
                {
                    System.Diagnostics.Debug.WriteLine(exception.Message);
                }
            }

            c.Children.Clear(); 
then this.Children.Remove(c); does not work cos you're not going to add it to the page before removing it!

and if you're adding it to page, there will be no memory leak cos the GC will automatically collects them and this.Children.Remove(c); is unnecessary.

haughtycool:

Thank you. Our discussion is very interesting. 

no problems, glad to help you