Introduction to the concept of TLB under Linux

TLB: Translation lookaside buffer, which is the bypass conversion buffer, or page table buffer; it stores some page table files (virtual address to physical address conversion table). Also known as fast watch technology. Since the "page table" is stored in the main memory, the cost of querying the page table is very high, resulting in a TLB. Addressing mode in X86 protected mode: Segment logical address —〉Linear address—〉Page address; Page address=Page start address+Intra-page offset address; Corresponding to virtual address: Call page (page) Corresponding to the physical address: called frame (page frame); The system memory of the X86 system stores two levels of page tables, the first level page table is called page directory, and the second level is called page table. There is no essential difference between the TLB and the primary and secondary caches in the CPU, except that the former caches the page table data and the latter two cache the actual data.

Linux generally uses a level 3 page table, or a level 4 page table to manage virtual address memory space. TLB is mainly used for address translation to speed up the conversion of physical addresses and logical page addresses. MMU is mainly responsible for implicit and access rights management.