Subject: Re: Autosizing NVNODE
To: David Brownlee <abs@netbsd.org>
From: John Franklin <franklin@elfie.org>
List: tech-kern
Date: 01/29/2003 17:38:28
On Wed, Jan 29, 2003 at 10:18:21PM +0000, David Brownlee wrote:
> 	NVNODE defaults to (NPROC + NTEXT + 100), which is generally
> 	way too small on a machine running in any kind of fileserving
> 	capacity. It can be set in a kernel config, but that can make
> 	sharing a kernel between machines with widely different memory
> 	values difficult.
> 
> 	What do people think of a BUFCACHE like value which would allow
> 	you to pick a percentage of memory to use for NVNODE?

It has precedent in the system, it is something that needs to be cranked
up on file servers, so in that sense it's ok.

On the other hand, I'd like to see BSD do less pre-allocating of such
things and let the kernel allocate them as needed, as many as needed and
then start refining the policies and algorithms to manage such
resources.   They kernel could keep a pool of memory around for
emergency "need space to work while I flush this stuff out," but
everything else should be on-demand.

UVM and UBC are a start towards this, but there's still plenty of
resources that need to be made dynamic.


jf
-- 
John Franklin
franklin@elfie.org
ICBM: 3543'56"N 7853'27"W