Re: [uml-devel] Re: madvise(DONTNEED) on tmpfs pages instead of /dev/anon

[Blaisorblade <blaisorblade@yahoo.it>]

On Monday 22 August 2005 22:24, Jeff Dike wrote:
> On Fri, Aug 12, 2005 at 07:00:26PM +0200, Blaisorblade wrote:
> > Yes, but for the VM, there is nothing else than pagecache and swapcache
> > and swap entries. Since that call will drop them, on normal files backing
> > store will remain, on tmpfs everything will vanish!

> > Hope you'll implement this soon, if it works.

> There was a small omission in my quick analysis, which you alluded to
> above.

> It's removed from the address space, but preserved in the page cache.
Yes, yesterday I realized this point. The pagecache has one additional 
reference, which is only deleted after try_to_unmap() (the rmap function to 
detach a page from page tables) succeeds (grep try_to_unmap mm/*.c to find 
the caller).

In fact, the madvise() comment only talks about anonymous memory.

Rik, is there any hope to extend madvise() to cater for this?
> Run the test below to see this.
-- 
Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!".
Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894)
http://www.user-mode-linux.org/~blaisorblade

	

	
		
___________________________________ 
Yahoo! Mail: gratis 1GB per i messaggi e allegati da 10MB 
http://mail.yahoo.it



-------------------------------------------------------
SF.Net email is Sponsored by the Better Software Conference & EXPO
September 19-22, 2005 * San Francisco, CA * Development Lifecycle Practices
Agile & Plan-Driven Development * Managing Projects & Teams * Testing & QA
Security * Process Improvement & Measurement * http://www.sqe.com/bsce5sf
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel