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Could you describe how is memory management done in .NET?

Answer

General overview

The garbage collector allocates and frees virtual memory for you on the managed heap.

Key ideas

• CLR - Automatic memory management
• Managed memory
• Memory allocation
• Releasing memory
• Cleaning up unmanaged resources
• Garbage collector (GC)
• Managed heap
• Large Object Heap - 85000 bytes+
• Generations 0,1,2
• IDisposable/Dispose pattern

Secret weapons

• Value types are not always stored on stack.
• Allocation on a stack is only "the stack pointer" modification.
• Stack is just an implementation detail (think about other implementation of CLI=Common Language Infrastructure)

Memory concepts

• Each process has its own, separate virtual address space.
• By default, on 32-bit computers, each process has a 2-GB user-mode virtual address space.

Virtual memory

• Free/Reserved/Commited
• Virtual address space can get fragmented. This means that there are free blocks, also known as holes, in the address space.
• You can run out of memory if you run out of virtual address space to reserve or physical space to commit.

 

Excellent links

• https://docs.microsoft.com/en-us/dotnet/standard/garbage-collection/

You must read these (no excuses):

• https://blogs.msdn.microsoft.com/ericlippert/2009/04/27/the-stack-is-an-implementation-detail-part-one/
• https://blogs.msdn.microsoft.com/ericlippert/2009/05/04/the-stack-is-an-implementation-detail-part-two/

 

 

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