Writeback

The Linux Page Cache & Page Writeback The Core Concept: Disk access is measured in milliseconds; RAM access is measured in nanoseconds. To bridge this massive performance gap, Linux dynamically uses free physical RAM to cache blocks of disk data. This relies on temporal locality: the computing principle that if data is accessed once, it is highly likely to be accessed again very soon. 1. Reading from Disk The cache is granular; Linux caches specific pages of files based on what you actually access, not whole files by default. ...