WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-users

[Xen-users] Xen 3 not seeing the right amount of RAM on x86_64

To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-users] Xen 3 not seeing the right amount of RAM on x86_64
From: "Chuck McIntyre" <chuck.mcintyre@xxxxxxxxx>
Date: Tue, 27 Nov 2007 20:47:34 -0800
Delivery-date: Tue, 27 Nov 2007 20:48:21 -0800
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to:subject:mime-version:content-type:content-transfer-encoding:content-disposition; bh=UISfzLOAQaFN6BEXc7gh1mjj3wV9YRaA148v8Y3dDbA=; b=joDyc6Rt8u+/8w3Uqz/X87vmePsoPGbfdrOewYc5/ykK+sUrL4+5Jri9PdZdpF/Wx7OcR5pdfZkKSucB6s7P2cyJAcGdO2KyVPgG+bKmxACJDwbC9BcG0sX7hkENbrlLkdm6TfT3lMCbX2slo0W/d7dyLDV3aNMpP+wBPT438Gw=
Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=received:message-id:date:from:to:subject:mime-version:content-type:content-transfer-encoding:content-disposition; b=J0DzU+NFCaEwYRY5AfqxSorm+VZmzde4pfCsv1IBsg5SMBu48C+SCFWgEZIS6CaZ7d1Z4xnmLQ1Loc5J2/vg7ZKa5X5Xe6NKSqFhOQUluNOCvWte18phYmZx25OnmiIgyKVFH6LMCnDy+Z5DqYLdnwfzDzH5T3Qpn5xFF8eJExo=
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
Hi,

I am having a problem where Xen is not seeing the appropriate amount
of memory allocated. At first I thought this was similar to previously
described issues with the BIOS remapped hole for PCI devices (such as
in a post here 
http://lists.xensource.com/archives/html/xen-users/2005-07/msg00177.html),
however, we only see about 3.5GB (see below) of RAM regardless of
whether we have a system with 4GB of RAM or 8GB of RAM (as seen by the
BIOS). Regardless, when we boot into the non-xen kernel available on
the same box, the OS then sees all the available RAM.

I have tried to provide as much relevant information as I could
without being spammy. Please let me know if I need to provide
additional details. I would appreciate any help here, as this one has
us stumped, or do we have a bug with our hardware version?

__4GB system___

[me@molotov ~]$ uname -a
Linux molotov.mydomain 2.6.18-8.1.15.el5.centos.plusxen #1 SMP Thu Oct
25 07:21:34 EDT 2007 x86_64 x86_64 x86_64 GNU/Linux
[me@molotov ~]$ rpm -qa | grep xen
xen-3.0.3-25.0.4.el5
xen-libs-3.0.3-25.0.4.el5
xen-libs-3.0.3-25.0.4.el5
kernel-xen-2.6.18-8.1.15.el5.centos.plus
[me@molotov ~]$ grep MemTotal /proc/meminfo
MemTotal:      3428400 kB
top gives me:
Mem:   3428400k total,   422916k used,  3005484k free,    21648k buffers
[root@molotov ~]# xm info 2>&1 | grep memory
total_memory           : 3535
free_memory            : 129
xentop gives me:
Mem: 3620404k total, 3488052k used, 132352k free    CPUs: 4 @ 2200MHz
dmesg
BIOS-provided physical RAM map:
 Xen: 0000000000000000 - 00000000d1d4c000 (usable)
On node 0 totalpages: 859468
  DMA zone: 859468 pages, LIFO batch:31
DMI present.

-=After reboot=-

BIOS gives me:
Initializing USB Controllers .. Done.
4096MB OK
[me@molotov ~]$ grep MemTotal /proc/meminfo
MemTotal:      4050520 kB
top gives
Mem:   4050520k total,   264668k used,  3785852k free,    20612k buffers
dmesg
BIOS-provided physical RAM map:
 BIOS-e820: 0000000000000000 - 000000000009dc00 (usable)
 BIOS-e820: 000000000009dc00 - 00000000000a0000 (reserved)
 BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved)
 BIOS-e820: 0000000000100000 - 00000000dcff0000 (usable)
 BIOS-e820: 00000000dcff0000 - 00000000dcffe000 (ACPI data)
 BIOS-e820: 00000000dcffe000 - 00000000dd000000 (ACPI NVS)
 BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
 BIOS-e820: 00000000fec00000 - 00000000fec01000 (reserved)
 BIOS-e820: 00000000fee00000 - 00000000fef00000 (reserved)
 BIOS-e820: 00000000ff700000 - 0000000100000000 (reserved)
 BIOS-e820: 0000000100000000 - 0000000123000000 (usable)
DMI present.
Bootmem setup node 0 0000000000000000-0000000080000000
Bootmem setup node 1 0000000080000000-0000000123000000
On node 0 totalpages: 515808
  DMA zone: 2728 pages, LIFO batch:0
  DMA32 zone: 513080 pages, LIFO batch:31
On node 1 totalpages: 515144
  DMA32 zone: 373744 pages, LIFO batch:31
  Normal zone: 141400 pages, LIFO batch:31



__ 8GB System __

[me@molotov ~]$ uname -a
Linux benelli.mydomain 2.6.18-8.1.15.el5.centos.plusxen #1 SMP Thu Oct
25 07:21:34 EDT 2007 x86_64 x86_64 x86_64 GNU/Linux
[me@molotov ~]$ rpm -qa |  grep xen
kernel-xen-2.6.18-8.1.15.el5.centos.plus
xen-libs-3.0.3-25.0.4.el5
xen-libs-3.0.3-25.0.4.el5
xen-3.0.3-25.0.4.el5
[me@benelli ~]$ grep MemTotal /proc/meminfo
MemTotal:      3428336 kB
top gives me:
Mem:   3428336k total,   437888k used,  2990448k free,    16580k buffers
[root@benelli ~]# xm info 2>&1| grep memory
total_memory           : 3535
free_memory            : 0
xentop gives me:
Mem: 3620336k total, 3620064k used, 272k free    CPUs: 4 @ 2200MHz
dmesg
BIOS-provided physical RAM map:
 Xen: 0000000000000000 - 00000000d1d3c000 (usable)
DMI present.

-=After Reboot=-

BIOS gives me:
Initializing USB Controllers .. Done.
8192MB OK

After reboot into non-xen kernel:

[root@benelli ~]# grep MemTotal /proc/meminfo
MemTotal:      8181124 kB
Top gives
Mem:   8181124k total,   284732k used,  7896392k free,    16944k buffers
dmesg
BIOS-provided physical RAM map:
 BIOS-e820: 0000000000000000 - 000000000009c400 (usable)
 BIOS-e820: 000000000009c400 - 00000000000a0000 (reserved)
 BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved)
 BIOS-e820: 0000000000100000 - 00000000dcfe0000 (usable)
 BIOS-e820: 00000000dcfe0000 - 00000000dcfee000 (ACPI data)
 BIOS-e820: 00000000dcfee000 - 00000000dcff0000 (ACPI NVS)
 BIOS-e820: 00000000dcff0000 - 00000000dcffe000 (reserved)
 BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
 BIOS-e820: 00000000fec00000 - 00000000fec01000 (reserved)
 BIOS-e820: 00000000fee00000 - 00000000fef00000 (reserved)
 BIOS-e820: 00000000ff700000 - 0000000100000000 (reserved)
 BIOS-e820: 0000000100000000 - 0000000223000000 (usable)
DMI present.
Bootmem setup node 0 0000000000000000-0000000123000000
Bootmem setup node 1 0000000123000000-0000000223000000
On node 0 totalpages: 1030931
  DMA zone: 2723 pages, LIFO batch:0
  DMA32 zone: 886808 pages, LIFO batch:31
  Normal zone: 141400 pages, LIFO batch:31
On node 1 totalpages: 1034240
  Normal zone: 1034240 pages, LIFO batch:31


__Both Systems__

Here is grub.conf (equivalent on both systems):
default=0
timeout=5
serial --unit=0 --speed=9600
terminal --timeout=5 serial console
title CentOS (2.6.18-8.1.15.el5.centos.plusxen)
        root (hd0,0)
        kernel /boot/xen.gz-2.6.18-8.1.15.el5.centos.plus console=vga
        module /boot/vmlinuz-2.6.18-8.1.15.el5.centos.plusxen ro
root=/dev/md0 console=ttyS0 console=ttyS0,9600n8 console=tty0
xencons=tty
        module /boot/initrd-2.6.18-8.1.15.el5.centos.plusxen.img
title CentOS (2.6.18-8.1.15.el5.centos.plus)
        root (hd0,0)
        kernel /boot/vmlinuz-2.6.18-8.1.15.el5.centos.plus ro
root=/dev/md0 console=ttyS0 console=ttyS0,9600n8 console=tty0
xencons=tty
        initrd /boot/initrd-2.6.18-8.1.15.el5.centos.plus.img

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users