From owner-freebsd-questions  Wed May  8 23:37:08 1996
Return-Path: owner-questions
Received: (from root@localhost)
          by freefall.freebsd.org (8.7.3/8.7.3) id XAA15418
          for questions-outgoing; Wed, 8 May 1996 23:37:08 -0700 (PDT)
Received: from labinfo.iet.unipi.it (labinfo.iet.unipi.it [131.114.9.5])
          by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id XAA15413
          for <questions@freebsd.org>; Wed, 8 May 1996 23:37:02 -0700 (PDT)
Received: from localhost (luigi@localhost) by labinfo.iet.unipi.it (8.6.5/8.6.5) id IAA01660; Thu, 9 May 1996 08:20:44 +0200
From: Luigi Rizzo <luigi@labinfo.iet.unipi.it>
Message-Id: <199605090620.IAA01660@labinfo.iet.unipi.it>
Subject: Re: Disk cache?
To: davidg@Root.COM
Date: Thu, 9 May 1996 08:20:44 +0200 (MET DST)
Cc: s_koyin@eduserv.its.unimelb.EDU.AU, questions@freebsd.org
In-Reply-To: <199605090409.VAA01491@Root.COM> from "David Greenman" at May 8, 96 09:08:54 pm
X-Mailer: ELM [version 2.4 PL23]
Content-Type: text
Sender: owner-questions@freebsd.org
X-Loop: FreeBSD.org
Precedence: bulk

> All file accesses in FreeBSD are cached and the dynamic cache can grow as
> large as the amount of RAM in your machine.

Is this really true ? from vm_pageout.c (2.1R) I see the following,

	...
        if (cnt.v_page_count > 1024) {
                cnt.v_cache_max = (cnt.v_free_count - 1024) / 2;
                cnt.v_cache_min = (cnt.v_free_count - 1024) / 8;
                cnt.v_inactive_target = 2*cnt.v_cache_min + 192;
        } else {
                cnt.v_cache_min = 0;
                cnt.v_cache_max = 0;
                cnt.v_inactive_target = cnt.v_free_count / 4;
        }

I assume it means that there is a reserve of pages for other stuff
than file buffers.

	Luigi
====================================================================
Luigi Rizzo                     Dip. di Ingegneria dell'Informazione
email: luigi@iet.unipi.it       Universita' di Pisa
tel: +39-50-568533              via Diotisalvi 2, 56126 PISA (Italy)
fax: +39-50-568522              http://www.iet.unipi.it/~luigi/
====================================================================