sendfile and page usage statistics

[Igor Sysoev]

As I understand if sendfile() with hardware TX chsum or TSO are used,
then CPU does not touch file pages at all. So pagedaemon never set
PG_REFERENCED to vnode object pages while scanning them.
Does VM set PG_REFERENCED by another way ? Otherwise, often used files
that accessed by sendfile() only have small chances to be cached by VM.


-- 
Igor Sysoev
http://sysoev.ru/en/