Memory Allocation - Generation GC

Since it is generational GC, in the marking phase it does not go through the entire heap.

It makes the following assumptions

1. The newer an object is, the shorter its lifetime will be.
2. The older an object is, the longer its lifetime will be.
3. Collecting a portion of the heap is faster than collecting the whole heap.

The picture shows how it works. A few things to remember

1. Generation 0 is empty immediately after a garbage collection and is where
new objects will be allocated.

2. Any objects that were in generation 0 that survived the garbage collection would be now in generation 1 and so on.

3. The objects in a generation are examined only when generation reaches its budget, which usually requires several garbage collections of generation 0. When the CLR initializes, it selects budgets for all three generations. The budget for generation 0 is about 256 KB, and the budget for generation 1 is about 2 MB. The budget for generation 2 is around 10 MB.

4. The larger the budget, the less frequently a garbage collection will occur.

5. The managed heap supports only three generations: generation 0, generation 1, and generation 2; there is no generation 3.

6. Garbage collector dynamically modifies generation 0's budget after every collection.