Mastering Linux Kernel Development

Page descriptor

Page frames are the smallest possible allocation units of memory and kernel needs to utilize them for all its memory needs. Some page frames would be required for mapping physical memory to virtual address spaces of user mode processes, some for kernel code and its data structures, and some for processing dynamic allocation requests raised by process or a kernel service. For efficient management of such operations, kernel needs to distinguish between page frames currently in use from those which are free and available. This purpose is achieved through an architecture-independent data structure called struct page, which is defined to hold all meta data pertaining to a page frame, including its current state. An instance of ...