Re: Possible regression: XEN 4.0.0 total_memory decrease

[Keir Fraser <keir.fraser@eu.citrix.com>]

Ah, hm, I think this is a bug in total memory reporting only. I think the
memory is still there in the free pools though. :-) How does xm info's
free_memory compare in the two cases? I bet it's a lot closer than 150MB
(assuming dom0 is allocated the same amount of memory in both cases, e.g.,
by explicitly specifying dom0_mem=xxx on Xen command line).

 -- Keir

On 15/04/2010 18:33, "Alex Williams" <awilliams@iweb.com> wrote:

> Hello,
> 
> Both builds run a 64-bit Xen kernel and 64-bit Dom0 kernel.
> 
> (XEN)  Xen  kernel: 64-bit, lsb, compat32
> (XEN)  Dom0 kernel: 64-bit, lsb, paddr 0xffffffff80200000 ->
> 0xffffffff805d388c
> 
> As for the RAM:
> 
> Xen 3.4.2: (XEN) System RAM: 3946MB (4041012kB)
> Xen 4.0.0: (XEN) System RAM: 4084MB (4182064kB)
> 
> I have also verified with only 2048MB installed in the system. Here are
> the results:
> 
> Xen 3.4.2: (XEN) System RAM: 2036MB (2084912kB)
> Xen 4.0.0: (XEN) System RAM: 1898MB (1943860kB)
> 
> Still 150MB RAM missing... it appears this problem is static and
> independant of the amount of RAM installed in the system.
> 
> Regards,
> 
> 
> 
> Keir Fraser wrote:
>> Are the hypervisor and dom0 kernel 64-bit or 32-bit? Xen prints a message
>> "System RAM: xxx" early during boot. Do these differ significantly for you
>> between 3.4.2 and 4.0.0?
>> 
>>  K.
>> 
>> On 15/04/2010 16:54, "Alex Williams" <awilliams@iweb.com> wrote:
>> 
>>> Hello,
>>> 
>>> I noticed a significant *decrease* (150MB) in "total_memory" on a host
>>> build using XEN 4.0.0 with kernel 2.6.18.
>>> 
>>> Here are the details:
>>> 
>>> Server = 4096MB RAM
>>> XEN 3.4.2 + kernel 2.6.18: xm info | grep total_memory = 4084
>>> XEN 4.0.0 + kernel 2.6.18: xm info | grep total_memory = 3946
>>> 
>>> The exact same kernel config file was used for both builds. I also made
>>> sure there is absolutely no difference on the hosts (while the builds
>>> are created on a different machine).
>>> 
>>> This seems like a regression, unless someone can provide suggestions on
>>> how to correct this?
>>> 
>>> Thanks.
>>> 
>> 
>> 
>> 
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