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

[Daniel Mealha Cabrita <dancab@xxxxxxxxxxxx>]

It looks like you're using a 32-bit Xen kernel without compiled PAE support.
Also looks like your non-Xen kernel is a 32-bit one with PAE support.

Em Qua 28 Nov 2007 02:47, Chuck McIntyre escreveu:
> 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

-- 
 Daniel Mealha Cabrita
 Divisao de Suporte Tecnico
 AINFO / Reitoria / UTFPR
 http://www.utfpr.edu.br

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