[CDBUG-talk] FreeBSD & 8GB RAM

Kevin McAleavey kevinmca1 at verizon.net
Wed Dec 30 03:51:47 EST 2009

 Apologies for the lengthy delay ... native 32 bit kernels can only see just under 4 GB natively, and I see that you have PAE enabled in the kernel which is permitting it to "see" your memory. However, controlling same is a different issue. Some CPU's do not properly support PAE and depend on the Microsoft kernel to "fake" it, and BSD 7's implementations (all) of PAE are buggy. If you check up on BSD7's PAE in the manual, you'll see that there are warnings about certain kernel drivers and hardware (NVidia for one) will put the kabosh to PAE's efforts by muddying the addresses.

 About all I can suggest trying is fiddling with the memory layout in your BIOS settings and see if one of them might make the kernel any happier. You might also give the BSD 8 release a shot - it's VERY good and quite stable. But beyond 4 GB is really the domain of the 64 bit realm as 32 bit addresses can only linearly reach to about 4GB before you run out of bits. Anything beyond that is voodoo and there's weak king fu at play there. Take heart in the fact that your kernel IS trying to do it, but you're suffering a Bronx handshake.  :)

At 02:53 PM 12/20/2009, Jaime wrote:
>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?
>CDBUG-talk mailing list
>CDBUG-talk at lists.nycbug.org

Why can't DOS ever say "Excellent command or filename"? 

Kevin McAleavey - kevinmca1 at verizon.net

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