Re: xen does not see more than 173800500k of memory

["Jan Beulich" <jbeulich@novell.com>]

This seems to correspond to the truncation at 166Gb for 32on64 support (see
xen/arch/x86/e820.c:machine_specific_memory_setup()). There used to be
a command line options to disallow creation of compat mode guests (thereby
allowing all memory to be used), but that option went away with fairly recent
changes.

Jan

>>> "Krysan, Susan" <KRYSANS@unisys.com> 23.08.07 00:33 >>>
Our test server (Unisys ES7000) has recently been upgraded with more
processors and more memory, so I am testing x86_64 xen with 64 cpus and
192gb.  I compiled xen with max_phys_cpus=64 and debug=y.  xen sees the
64 cpus, but only sees 173800500k of the 192gb.  I booted dom0 with
2048M and numa=on.  I get the same result when I configure the server to
have 176gb (xen still sees only 173800500k). Booting without numa=on
makes no difference.

 

xentop - 14:48:42   Xen 3.0-unstable

1 domains: 1 running, 0 blocked, 0 paused, 0 crashed, 0 dying, 0
shutdown

Mem: 173800500k total, 4324748k used, 169475752k free    CPUs: 64 @
3400MHz

      NAME  STATE   CPU(sec) CPU(%)     MEM(k) MEM(%)  MAXMEM(k)
MAXMEM(%) VCPUS

 NETS NETTX(k) NETRX(k) VBDS   VBD_OO   VBD_RD   VBD_WR SSID

  Domain-0 -----r         95    0.0    2097152    1.2   no limit
n/a    32

    0        0        0    0        0        0        0    0

 

When I configure the server with 160gb or less, xen sees all of the
memory. 

 

Also, when I boot with the SLES kernel, SLES can see the all of the
memory.

 

I assume there is not a memory limit on xen.  I would greatly appreciate
any help to resolve this problem.

 

Thanks,

Sue Krysan

Linux Systems Group

Unisys Corporation