Memory pool principle I (based on the whole block)

Created by QQ：851301776, mailbox ：[email protected], Welcome to technical exchange , This blog is mainly my own learning experience , Just to make a little progress every day ！

Personal motto ：
1. No one was born , As long as it is thick, it will happen .
2. You can have a low degree , You can skip school , But you have to learn

One 、 Memory pool design ideas

1. Memory pool solves the problem （malloc/free）

（1） Not conducive to memory management

（2） Memory fragmentation is severe

（3） Programs are prone to memory leaks , Eventually a memory overflow occurs

2. Memory pool design practices （4K）

（1） Partner algorithm

         Distribute ： hold 4K, according to 2 Of n Power method , from 0 Begin to assign to ：1/2/4/8/16/32/64/128/256/512/1K/2K These pieces , Core thinking ： Turn the whole block into pieces

Use ： Such as the need to 129 Bytes ： It will 256 This block is split again into ：128/64/32/16/8/4/2/1,

         Merge ： Combine two adjacent pieces of the same size , With the next piece . The first condition is that two blocks are adjacent , The second condition is that the two pieces must be the same size .

         Release ： Turn small pieces into big ones , Unified release

（2）slab

         No explanation here , You can see nginx Use slab Memory pool part of （slab The core is to ： For example, a 4K Page of , All become 4/8/16( Numbers are just examples ), This small piece ）