Analysis of the built-in garbage collection function of Go language

Go language’s built-in garbage collection (Garbage Collection) is an important feature of Go language. It can automatically manage memory that is no longer used in the program, thereby reducing the burden on programmers and improving Program performance. This article will analyze the built-in garbage collection function of the Go language, including the principles of garbage collection, the implementation of garbage collection, and some common garbage collection mechanisms.

1. The principle of garbage collection

The principle of garbage collection is to check the memory objects in the program, identify which memory objects are no longer used, and then release these memory objects for subsequent use use. The Go garbage collector uses the Mark-Sweep algorithm. The basic idea of ​​this algorithm is to mark all active objects and then clear all unmarked objects. The garbage collector of the Go language will scan the objects in the heap from time to time during the running of the program, mark active objects, and then clear out unmarked objects.

2. How to implement garbage collection

The built-in garbage collector in Go language uses concurrent mark scanning to perform garbage collection. During garbage collection, the Go language runtime system will stop all current user threads and start a dedicated GC coroutine to perform garbage collection operations. The GC coroutine scans the objects in the heap, marks active objects, and clears unmarked objects. During the scanning process, the GC coroutine will be executed concurrently with the user thread to reduce the impact of garbage collection on program performance.

3. Common garbage collection mechanisms

1. Reference counting method: This method maintains the reference count of the object. When the reference count is 0, it means that the object is no longer used. You can Recycle. However, the reference counting method has the problem of circular references, which prevents objects from being recycled correctly.
2. Garbage collector: The Go language's garbage collector uses a mark-and-clear algorithm, which can correctly handle circular references and ensure the correct release and recycling of memory.

4. Code example of garbage collector

The following is a simple code example that demonstrates the use of garbage collector in Go language:

package main

import "fmt"

func createObject() *int {
    num := 10
    return &num
}

func main() {
    var ptr *int
    ptr = createObject()

    fmt.Println(*ptr)

    // 垃圾回收器会在该函数执行完毕后自动回收createObject函数中创建的对象
}

In the above code example, the createObject function creates an integer object num and returns a pointer to the object. In the main function, call the createObject function to obtain the pointer of the object and print out the value of the object. After the main function is executed, the garbage collector will automatically recycle the objects created in the createObject function and release the memory space.

Conclusion

Through the analysis of this article, we understand the principles, implementation methods and common garbage collection mechanisms of the built-in garbage collection function of the Go language. The garbage collector can effectively manage the memory in the program and improve the performance and stability of the program. In the daily programming process, programmers can safely use the garbage collection function of the Go language without worrying about the cumbersome issues of memory management.

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