Date: 17 Mar 1999 03:20:15 +0100 From: Dag-Erling Smorgrav <des@flood.ping.uio.no> To: "David E. Cross" <crossd@cs.rpi.edu> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: evil maxusers Message-ID: <xzp6780luw0.fsf@flood.ping.uio.no> In-Reply-To: "David E. Cross"'s message of "Mon, 15 Mar 1999 21:16:26 -0500" References: <199903160216.VAA24377@cs.rpi.edu>
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"David E. Cross" <crossd@cs.rpi.edu> writes:
> What is evil abuot large maxusers? We have a crashing server (Pentium II-400)
> with maxusers set to 320. In a previous email to -hackers that I have since
> lost :I it was mentioned that you could lower maxusers, and the, by hand,
> up the MBUFs and NPROCs in the config file. However I have grepped the
> entire kernel source tree, and I can see that MAXUSERS is only used to
> set MBUFs and NPROCS (and other things derive from there, suich as
> MAXFILES). Why therefore will MAXUSERS=320 crash my system, while setting
> MAXUSERS to 64, and adjusting MBUFs and NPROCS by hand will not?
Because mbufs eat memory, and the kernel has a limited address space.
If I'm not mistaken, setting maxusers to 320 eats up to 90 MB in mbuf
clusters alone, which is almost half the kernel address space.
The kernel address space was increased to 1 GB a few days ago.If
you're running 4.0 (on a production server? I hope not), update your
sources and rebuild. If you're running 3.1, you can try to apply those
patches by hand, or wait for them to be MFCed. If you're running 2.x,
all bets are off.
dg 1999/03/11 10:28:47 PST
Modified files:
sys/i386/conf Makefile.i386 kernel.script
sys/i386/include pmap.h
Log:
Increased kernel virtual address space to 1GB. NOTE: You MUST have fixed
bootblocks in order to boot the kernel after this! Also note that this
change breaks BSDI BSD/OS compatibility.
Also increased default NKPT to 17 so that FreeBSD can boot on machines
with >=2GB of RAM. Booting on machines with exactly 4GB requires other
patches, not included.
Revision Changes Path
1.141 +2 -2 src/sys/i386/conf/Makefile.i386
1.2 +1 -1 src/sys/i386/conf/kernel.script
1.59 +4 -4 src/sys/i386/include/pmap.h
DES
--
Dag-Erling Smorgrav - des@flood.ping.uio.no
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