what is pagecache page

/*
 * Each physical page in the system has a struct page associated with
 * it to keep track of whatever it is 开发者_开发技巧we are using the page for at the
 * moment. Note that we have no way to track which tasks are using
 * a page, though if it is a pagecache page, rmap structures can tell us
 * who is mapping it.
 */

include/linux/mm_types.h

Here Please lemme know what is "pagecache page" means?

Thanks!

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The pagecache is - as the name suggests - a cache of physical pages.

http://www.moses.uklinux.net/patches/lki-4.html

It is used to store filesystem cache (disk cache).

Mmaped files seems to use pagecache too.

And the "pagecache page" means page, which belongs to pagecache