Date: Fri, 22 Aug 2003 16:58:01 -0700 From: Mike Hunter <mhunter@ack.Berkeley.EDU> To: freebsd-hackers@freebsd.org Subject: Building kernels with large MAXDSIZ Message-ID: <20030822235801.GA21027@ack.Berkeley.EDU>
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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 <freebsd-questions-local@be-well.no-ip.com> ----- X-Authentication-Warning: be-well.ilk.org: lowell set sender to freebsd-questions-local@be-well.ilk.org using -f To: Mike Hunter <mhunter@ack.Berkeley.EDU> 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 <freebsd-questions-local@be-well.no-ip.com> 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 <mhunter@ack.Berkeley.EDU> 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
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