File Access Method Reducing Process Page Table Load
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Solution Overview
Problem
The existing file access methods for non-volatile memory (NVM) based file systems are complex and inefficient, leading to increased load on the process page table due to the need for caching and mapping entries, which hampers access speed and efficiency.
Innovation Solution
A method that uses a file access apparatus and storage device to manage files within a non-volatile memory by establishing a mapping relationship between virtual and physical address spaces, allowing direct access to files through a global file page table, thereby reducing the need for process page table entries and enhancing access efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If MMAP manner is used to access file system in NVM, then access speed is improved, but process page table load is increased
Solution Approach 1:
The patent segments the address space management by introducing a file-specific virtual address space that is separate from the process virtual address space. The file system is divided into multiple files, each with its own virtual address space managed independently through file-specific page tables, reducing the burden on the process page table while maintaining fast access speeds.
Solution Approach 2:
The patent introduces a file-specific virtual address space as an intermediary layer between the process and the physical file system in NVM. This intermediary allows direct memory-mapped access without requiring entries in the process page table, thus maintaining access speed while reducing page table load.
2Productivity
If cached page table entry is added to process page table for direct file access, then access efficiency is improved, but system overhead is increased
Solution Approach 1:
The patent segments the page table structure into process-specific page tables and file-specific page tables. File access information is stored in file-specific page tables rather than process page tables, reducing system overhead while maintaining access efficiency through direct virtual-to-physical address translation.
Solution Approach 2:
The patent adds a new dimension to address space management by introducing file-specific virtual address spaces that exist independently from process address spaces. This dimensional separation allows efficient file access without consuming process page table resources.
3Adaptability or versatility
If NVM is managed in page-based manner with byte addressing, then memory access flexibility is improved, but access process complexity is increased
Solution Approach 1:
The patent applies different quality characteristics to different parts of the memory system: byte-level addressing flexibility is provided at the file level through file-specific virtual address spaces, while page-based management is maintained at the physical level for NVM. This local differentiation maintains flexibility without increasing overall process complexity.
Data Source
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AI summary
A file access method and apparatus, and a storage device are disclosed, where the file access method is applied to a storage device in which a file system is established in a memory. In the method, the storage device may obtain, according to a file identifier of a to-be-accessed first target file, an index node of the first target file in metadata, where the index node of the first target file stores information about first virtual space of the first target file in global virtual space (205); and the storage device may map the first virtual space onto second virtual space of a process according to the information that is about the first virtual space and that is recorded in the index node (210), and perform addressing on an added file management register (220 and 225). The file management register stores a base address of a page directory of a global file page table. Therefore, the storage device can access the first target file according to a start address of the first virtual space and the base address of the page directory of the global file page table. According to the method, load on a process page table can be reduced, and system overheads can be reduced.