Linux memory mechanism

In Linux, we often find that the idle memory is very small. it seems that all the memory is occupied by the system. on the surface, it seems that the memory is not enough. This is an excellent feature of Linux memory management, which is different from Windows memory management. The main feature is that, no matter how large the physical memory is, Linux fully utilizes it and reads hard disk data called by some programs into the memory, improve the data access performance of Linux systems by utilizing the high-speed features of memory read/write. Windows only requires memory.

In Linux, we often find that the idle memory is very small. it seems that all the memory is occupied by the system. on the surface, it seems that the memory is not enough. This is an excellent feature of Linux memory management, which is different from Windows memory management. The main feature is that, no matter how large the physical memory is, Linux fully utilizes it and reads hard disk data called by some programs into the memory, improve the data access performance of Linux systems by utilizing the high-speed features of memory read/write. In Windows, memory is allocated to applications only when memory is needed, and large memory space cannot be fully utilized. In other words, Linux will be able to make full use of each additional physical memory, giving full play to the benefits of hardware investment, while Windows only uses it as a decoration, even if it increases by 8 GB or even greater.

Linux uses idle physical memory to divide a portion of the space into cache and buffers to improve data access performance.

Page cache is a major disk cache implemented by the Linux kernel. It is mainly used to reduce disk I/O operations. Specifically, by caching data in the disk to the physical memory, you can change access to the disk to access the physical memory.

The value of high-speed disk cache lies in two aspects: first, the access speed to the disk is much lower than the access speed to the memory. Therefore, the access speed from memory is faster than that from the disk. Second, once the data is accessed, it is likely to be accessed again in a short period of time.