Linux Kernel Development, Second Edition

Chapter 15. The Page Cache and Page Writeback

The linux kernel implements a primary disk cache called the page cache. The goal of this cache is to minimize disk I/O by storing in physical memory data that would otherwise be accessed from disk. This chapter deals with the page cache and page writeback.

Disk caches are beneficial for two reasons. First, disk access is magnitudes slower than memory access. Accessing data from memory rather than the disk is much faster. Second, data accessed once will, with a high likelihood, find itself accessed again in the near future. This principle, that access to a particular piece of data tends to be clustered in time, is called temporal locality. Temporal locality ensures that if data is cached on its first ...