Subject: Re: pool(9) revisited
To: Jason Thorpe <thorpej@nas.nasa.gov>
From: Eduardo E. Horvath <eeh@one-o.com>
List: tech-kern
Date: 07/13/1998 19:05:37
May as well demonstrate my ignorance on this subject.

On Mon, 13 Jul 1998, Jason Thorpe wrote:

> On Mon, 13 Jul 98 12:45:27 +0200 
>  Paul Kranenburg <pk@cs.few.eur.nl> wrote:

>  > 	* no fixed upper limit on a pool's size. Let the page daemon
>  > 	  reclaim pages when running low on memory.
>  > 	  Optionally set a minimum amount of pool items that cannot be
>  > 	  reclaimed.
> 
> ...that works if you use pageable memory... but for some things, I might
> want to allocate a page, and map it w/ e.g. a direct-mapped segment (like
> KSEG/KSEG0 on Alpha or MIPS).  So, this has to be limited for use by
> the default allocator your pool code provides.

I believe the pager does not directly track the use of the allocated
memory.  What it does is try to allocate elements so as to coalesce free
pages (slabs/pools/whatever).  Then when the page daemon runs it queries
each pool to see whether it has any pages to give up.

=========================================================================
Eduardo Horvath				eeh@one-o.com
	"I need to find a pithy new quote." -- me