Cache coerency in Linux

natasha · 08-07-2006, 02:38 AM

Hello everybody,
how does Linux ensure cache coherency, that is, when one process open a file (and hence the file is cached) while another process maps the file into its address space, which assures content of file coherence?
Kisses,

Nat

timmeke · 08-07-2006, 05:12 AM

A file is not stored in memory (ie disk cache) when you open it.
Caching is only used when you read or write the file, to improve IO performance.

The disk caching mechanism ensures coherency.

Of course, a program can read an entire file and store a copy of the contents in it's own memory space, but than it's up to the program to manage that memory.