Can't build kernel with 4GB of memory (MAXDSIZE)

Lowell Gilbert freebsd-questions-local at
Fri Aug 22 08:34:47 PDT 2003

Mike Hunter <mhunter at 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 4.8-RELEASE-p3 FreeBSD
> 4.8-RELEASE-p3 #1: Tue Aug 19 14:24:09 GMT 2003
> root at  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...

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