Memory allocation and avoiding memory waste in Go language

With the continuous development of software development technology, the requirements for programming languages ​​are becoming higher and higher. In addition to powerful functions and concise syntax, memory management and performance are also the focus of many developers. As a statically typed, compiled language, Go language has features such as fast compilation, efficient execution, and garbage collection. However, memory management has a huge impact on performance. How to allocate memory and avoid memory waste in Go also needs to be mastered. Key skills.

1. Memory allocation

In the Go language, the memory of all variables is allocated on the heap. Using the Go language's built-in new function and make function, you can respectively allocate pointer variables and variables of reference types such as slice, map, and channel.

newThe function of the function is to create a pointer to a variable and allocate memory space for it, for example:

var ptr *int
ptr = new(int)
*ptr = 10

In the above code, a pointer to ## is first defined #int type pointer variable ptr, then use new(int) to allocate space for an integer variable, and assign its address to ptr , and finally you can assign a value to this variable through *ptr=10.

The

make function is used to initialize reference type variables. When initializing slice, map, channel and other types, you need to use the make function to allocate memory space. , for example:

s1 := make([]int, 10)
m1 := make(map[string]int)
c1 := make(chan int)

The above code creates an int type slice with 10 elements, an empty string type as key, int type as value map, and an int type unbuffered channel.

It should be noted that when multiple Go coroutines access the same object concurrently, locking or channel and other mechanisms need to be used to ensure the correctness and stability of the program.

2. Avoid memory waste

Memory waste means that the program allocates too much memory space, but actually only uses part of it or does not use it. This situation occurs in some low-end Equipment or large data volumes require special attention. The following are several ways to avoid memory waste in the Go language:

Control slice capacity

When creating a slice, you can directly specify its length and capacity, for example

s1 := make([]int, 10, 20), the length is 10 and the capacity is 20, which means that the slice can store 20 int type data, but in fact only the first 10 are used. Excessive capacity will waste memory, so it needs to be flexibly controlled according to the actual situation and expanded when necessary.

Reuse objects

In the Go language, memory allocation and garbage collection will take up a large part of the time, so try to avoid frequent memory allocation and release in the program. . You can use technologies such as object pools to pre-allocate memory for some commonly used objects and reuse them, thereby reducing memory waste and improving program efficiency.

Using pointers

In the Go language, the value of a variable is passed by value, that is, the address of the variable will be copied, which is very expensive. In order to save memory, you can use pointers to pass parameters and return values. For example:

func foo(a *int) {
    *a = 10
}

func main() {
    var n int
    foo(&n)
    fmt.Println(n)
}

In the above code, a parameter a of pointer type is defined and assigned a value in the function body. When calling the

foo function, pass the address of the variable n to the foo function, and n## in the foo function #After assignment, n in the main function will also be affected.

Avoid large block memory allocation

4. In situations where a large amount of memory operation is required, the Go language can use a memory pool to avoid frequent memory allocation. The memory pool can allocate a large piece of memory, divide it into some small, fixed-size memory blocks, use it from the memory pool when needed, and then return it to the memory pool after use, which can effectively avoid large blocks of memory. of waste.

In short, in the Go language, memory management is very important for both performance and program correctness. Developers need to master relevant technologies to avoid memory waste and improve program efficiency, thereby making the program more efficient and stable.

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