From owner-freebsd-hackers@FreeBSD.ORG Fri Aug 22 16:58:03 2003 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 33C5516A4BF for ; Fri, 22 Aug 2003 16:58:03 -0700 (PDT) Received: from ack.Berkeley.EDU (ack.Berkeley.EDU [128.32.206.66]) by mx1.FreeBSD.org (Postfix) with ESMTP id AAD8343FE9 for ; Fri, 22 Aug 2003 16:58:01 -0700 (PDT) (envelope-from mhunter@ack.Berkeley.EDU) Received: (from mhunter@localhost) by ack.Berkeley.EDU (8.11.3/8.11.3) id h7MNw1t21916 for freebsd-hackers@freebsd.org; Fri, 22 Aug 2003 16:58:01 -0700 (PDT) Date: Fri, 22 Aug 2003 16:58:01 -0700 From: Mike Hunter To: freebsd-hackers@freebsd.org Message-ID: <20030822235801.GA21027@ack.Berkeley.EDU> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.1i Subject: Building kernels with large MAXDSIZ X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 22 Aug 2003 23:58:03 -0000 Greetings hackers, I recently wrote a message to freebsd-questions@freebsd.org about trying to build a kernel with a large MAXDSIZ for some large network data crunching I'm trying to do. I got this reply: ----- Forwarded message from Lowell Gilbert ----- X-Authentication-Warning: be-well.ilk.org: lowell set sender to freebsd-questions-local@be-well.ilk.org using -f To: Mike Hunter Cc: freebsd-questions@freebsd.org reply-to: freebsd-questions@freebsd.org Subject: Re: Can't build kernel with 4GB of memory (MAXDSIZE) From: Lowell Gilbert Date: 22 Aug 2003 11:22:52 -0400 In-Reply-To: <20030820181346.GA21829@ack.Berkeley.EDU> User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 Mike Hunter writes: > I can't seem to get a new kernel working with increased memory parameters: > > I tried adding the following to my KERNCONF: > > options MAXDSIZ="(4096UL*1024*1024)" > options DFLDSIZ="(2048UL*1024*1024)" > > On 5-current (as of about 6 months ago) this produced an ungraceful > init.conf bomb-out. > > I tried again yesterday with a 4.8 box > > uname -a > FreeBSD mynewserver.net.berkeley.edu 4.8-RELEASE-p3 FreeBSD > 4.8-RELEASE-p3 #1: Tue Aug 19 14:24:09 GMT 2003 > root@mynewserver.net.berkeley.edu:/usr/obj/usr/src/sys/raeu i386 > > (cvsup'd some time after August 11) > > It gave me a similar but slightly more graceful bomb-out "I'm not going > anywhere without my init!\n\nRebooting in 15 seconds....") > > So, I think I'm missing something here :) The machine in question has 4GB > of ram, and I'd like to be able to use all of it for some nasty > number-crunching I'm trying to do. Any suggestions? I'm sorry, but you need to leave some space for the kernel and its data structures. I'm not sure how close to the edge you can tune it, but much beyond 3GB or so will probably need some real hacker knowledge... ----- End forwarded message ----- I found this link which helped me understand what I was doing wrong: http://docs.freebsd.org/cgi/getmsg.cgi?fetch=83003+0+archive/2002/freebsd-hackers/20020804.freebsd-hackers The question that remains for me is this: Exactly how big can I set MAXDSIZ, and how can I influence that maximum? The machine I'm working with is running 4.8, but I've had the same kinds of problems on 5-CURRENT as well. Thanks, Mike