RE: How the GC reclaim the memory of the objects with circled reference
From: Chris Lyon [MSFT] (clyon_at_online.microsoft.com)
Date: 03/08/04
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Date: Mon, 08 Mar 2004 18:09:14 GMT
Hi Bill
The .NET garbage collector uses a mark-sweep generational algorithm, which means it starts at GC Roots (locals, statics, threads, etc) and traces through their references.
Anything it doesn't touch is considered garbage and is eventually collected. Straight reference counting algorithms break down ith circular references, as you've
demonstrated.
You can read more about how .NET's GC works in these articles:
http://msdn.microsoft.com/msdnmag/issues/1100/gci/
http://msdn.microsoft.com/msdnmag/issues/1200/GCI2/default.aspx
And this site is great for general GC information, including descriptions of various algorithms and analysis:
http://www.memorymanagement.org
Hope that helps.
-Chris
--------------------
>From: foolmelon@hotmail.com (Bill)
>Newsgroups: microsoft.public.dotnet.languages.csharp,comp.lang.java.programmer
>Subject: How the GC reclaim the memory of the objects with circled reference
>Date: 7 Mar 2004 12:38:05 -0800
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>
>Let's simplify using public data member. Say I have (the code should
>look same in C# and Java):
>
>Class A
>{
> public B m_b;
>}
>
>Class B
>{
> public A m_a;
>}
>
>A a = new A();
>B b = new B();
>a.m_b = b;
>b.m_a = a;
>
>When a and b are not referenced by any other objects, a and b still
>reference to each other. How does .NET know that a and b should be
>garbage collected?
>
>I raised the same question when JDK 1.0.x just came out, but don't
>recall that I saw a concreate answer (maybe I missed it somehow). I
>am pretty sure that Sun is handling it correctly in their current JVM.
> If anybody knows how it works in JVM, please make your comments here
>too. Thank you!
>
>Regards,
>Bill
>
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