Subject: Re: pmap_is_referenced() -- not used?
To: None <thorpej@zembu.com>
From: Lars Heidieker <paradoxix@heidieker.de>
List: tech-kern
Date: 01/26/2001 18:30:42
Jason R Thorpe wrote:

> On Fri, Jan 26, 2001 at 04:37:08PM +0100, Lars Heidieker wrote:
>
>  > Another thing that might help ist to put referenced pages at the end of
>  > the active list while scanning the active list.
>
> I'm not sure this is such a great idea.  If you're already near the
> end of the list, you could end up scanning that page again prematurely.
>
> --
>         -- Jason R. Thorpe <thorpej@zembu.com>

Sure, but why would you leave a page on the active queue (quiet near the
front) if its referenced, to scan it again on the next invocation of the
scanner? By this you scan the front of the list to hard. (Not giving a
referenced page a chance to get referenced again between two invocations of
the scanner) Recently referenced pages at the front might be forced to the
inactive list even if there are "not so recently used ones" further on in the
queue. Thats the way it looks to me. In both cases it can happen that all
pages on the active queue are referenced, so you have to scan across all of
them twice (in any case) and the scanner always starts at the front at
invocation.

lars