[CDBUG-talk] FreeBSD & 8GB RAM

Jaime jaime at snowmoon.com
Sun Dec 20 14:53:41 EST 2009

Does this make sense to any of you?

cerberus# dmesg | grep memory
real memory  = 9126805504 (8704 MB)
avail memory = 8403456000 (8014 MB)
cerberus# sysctl -a | grep w | grep mem:
hw.physmem: 4282679296
hw.usermem: 4163031040
hw.realmem: 536870912
cerberus# top |head -n 5
last pid:  5552;  load averages:  0.00,  0.00,  0.00  up 0+05:12:21    14:47:12
114 processes: 1 running, 112 sleeping, 1 stopped

Mem: 161M Active, 920M Inact, 114M Wired, 76K Cache, 112M Buf, 6823M Free
Swap: 4096M Total, 4096M Free

Note that in sysctl, the hw.realmem number is roughly 0.5GB, not 5GB.

So in sysctl, I see ~4GB physical and user memory, but only 0.5GB of
real memory.  (I don't even know what the distinction is, BTW.)

Yet in top and at boot time, I see about 8GB of RAM.

I have PAE compiled in the kernel.  In fact, just to double check:

cerberus# uname -a
FreeBSD cerberus.cairodurham.org 7.0-RELEASE FreeBSD 7.0-RELEASE #1:
Wed Sep 24 17:13:12 EDT 2008
jkikpole at test.cairodurham.org:/usr/obj/usr/src/sys/CERBERUS  i386
cerberus# cat /usr/src/sys/i386/conf/CERBERUS
# Add the default setup for a kernel with >4GB of RAM supported.
include PAE

# Change the name of the kernel.
ident           CERBERUS

# Add support for the ipfw command, including forwarding.
options         IPFIREWALL
options         IPFIREWALL_VERBOSE
options         IPFIREWALL_FORWARD

I'm at a loss.  This wouldn't bother me so much if the network monitor
that I started setting up on Thursday wasn't throwing alarms for using
over 101% of physical memory on this box.  :)  Take a look:

   Memory              Used       Total  Percentage
 Physical     4294964560M       4084M 4294967230%
 Swap                  0M       4096M          0%

Weird, huh?  Any thoughts or suggestions?  The OS is over a year old.
I should have a good chance to do some upgrades in a week or so, if I
don't come up with any better ideas.

Thanks in advance,

P.S. - Anyone know a reason I shouldn't cvsup the current 7-STABLE
tree and start building binaries today?

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