Re: Dirty Page cache in 2.4

[Mike Fedyk]

On Tue, Nov 06, 2001 at 10:55:57AM +0800, David Chow wrote:
> Dear all,
> 
> I've heard the memory management in 2.4 swap out dirty pages. Is it true 
> that dirty pages refer to the dirty pages of page cache and they may 
> also be swapped out? Thanks.
> 

No, very untrue.

To be more specific, there are dirty filesystem cache pages, and dirty
application pages.  Dirty filesystem pages will be written to the FS, while
dirty application pages will be swapped out.  

If an application page is chosen for swap out and it is not dirty, the VM
will just discard that page completely because it can beloaded from the app
or library on disk when needed again...

BTW, both VMs would do this.  This behavior is very fundamental to VM design.

Mike