xm info showing too much free ram

xm info showing too much free ram

[Hans-Christian Armingeon]

Hi,

My dom0 has 2g ram allocated, and I have 2.5 G Ram physically in my machine.
I needed more Ram in domU so I did a

# xm mem-set 0 1000

# xm list
Name                              ID Mem(MiB) VCPUs State  Time(s)
Domain-0                           0     1000     1 r-----   471.8
gentoo64-xen                       2      453     1 ------ 29318.7

Looks Ok.

Increasing the Ram of domU

# xm mem-set 2 1453

root@jam:~# xm list
Name                              ID Mem(MiB) VCPUs State  Time(s)
Domain-0                           0     1000     1 r-----   472.5
gentoo64-xen                       2     1453     1 ------ 29336.7

Lokks OK.

Look at the line where it says:
free_memory            : 1064

root@jam:~# xm info
host                   : jam
release                : 2.6.16-20060326.1-xen0
version                : #1 SMP Sun Mar 26 21:41:31 CEST 2006
machine                : x86_64
nr_cpus                : 1
nr_nodes               : 1
sockets_per_node       : 1
cores_per_socket       : 1
threads_per_core       : 1
cpu_mhz                : 2200
hw_caps                : 078bfbff:e3d3fbff:00000000:00000010:00000001:00000001:00000001
total_memory           : 2559
free_memory            : 1064
xen_major              : 3
xen_minor              : 0
xen_extra              : -unstable
xen_caps               : xen-3.0-x86_64
platform_params        : virt_start=0xffff800000000000
xen_changeset          : Fri Mar 24 17:48:03 2006 +0100 9435:11fee62328cc
cc_compiler            : gcc-Version 4.0.2 20050808 (prerelease) (Ubuntu 4.0.1-4ubuntu9)
cc_compile_by          : root
cc_compile_domain      : localdomain
cc_compile_date        : Fr Mär 24 23:14:02 CET 2006
root@jam:~# xm info
host                   : jam
release                : 2.6.16-20060326.1-xen0
version                : #1 SMP Sun Mar 26 21:41:31 CEST 2006
machine                : x86_64
nr_cpus                : 1
nr_nodes               : 1
sockets_per_node       : 1
cores_per_socket       : 1
threads_per_core       : 1
cpu_mhz                : 2200
hw_caps                : 078bfbff:e3d3fbff:00000000:00000010:00000001:00000001:00000001
total_memory           : 2559
free_memory            : 1064
xen_major              : 3
xen_minor              : 0
xen_extra              : -unstable
xen_caps               : xen-3.0-x86_64
platform_params        : virt_start=0xffff800000000000
xen_changeset          : Fri Mar 24 17:48:03 2006 +0100 9435:11fee62328cc
cc_compiler            : gcc-Version 4.0.2 20050808 (prerelease) (Ubuntu 4.0.1-4ubuntu9)
cc_compile_by          : root
cc_compile_domain      : localdomain
cc_compile_date        : Fr Mär 24 23:14:02 CET 2006

Is that correct?

I don't think so.

Johnny

Re: xm info showing too much free ram

[Keir Fraser]

On 30 Mar 2006, at 19:43, Hans-Christian Armingeon wrote:

> My dom0 has 2g ram allocated, and I have 2.5 G Ram physically in my 
> machine.
> I needed more Ram in domU so I did a

If you don't start your domU with a 'mem=2G' or similar as a boot 
parameter then the domU will be unable to increase its memory 
allocation beyond its initial boot-time allocation. In this case, 'xm 
list' is lying to you -- it tells you what memory target the tools has 
asked the domU to aim for, not what the domU is currently using. :-)

That's my guess anyway -- the free memory reported by 'xm info' is 
definitely the truth, so 'xm list' is lying and that's probably the 
reason why. Take a look in the domU and see what it thinks. Also in the 
domU, look at the contents of /proc/xen/balloon.

  -- Keir

Re: xm info showing too much free ram

[Ewan Mellor]

On Mon, Apr 03, 2006 at 05:45:07PM +0100, Keir Fraser wrote:

> 
> On 30 Mar 2006, at 19:43, Hans-Christian Armingeon wrote:
> 
> >My dom0 has 2g ram allocated, and I have 2.5 G Ram physically in my 
> >machine.
> >I needed more Ram in domU so I did a
> 
> If you don't start your domU with a 'mem=2G' or similar as a boot 
> parameter then the domU will be unable to increase its memory 
> allocation beyond its initial boot-time allocation. In this case, 'xm 
> list' is lying to you -- it tells you what memory target the tools has 
> asked the domU to aim for, not what the domU is currently using. :-)
> 
> That's my guess anyway -- the free memory reported by 'xm info' is 
> definitely the truth, so 'xm list' is lying and that's probably the 
> reason why. Take a look in the domU and see what it thinks. Also in the 
> domU, look at the contents of /proc/xen/balloon.

Yes, that's right -- xm list shows the configured or requested memory, not the
amount it's actually using.  Personally, I'd consider that a bug -- feel free
to file it.

Ewan.

Re: xm info showing too much free ram

[Hans-Christian Armingeon]

Hello Keir,

is it difficult to fix that?

Maybe this is only a two liner.

Johnny

Am Montag, 3. April 2006 19:10 schrieb Ewan Mellor:
> On Mon, Apr 03, 2006 at 05:45:07PM +0100, Keir Fraser wrote:
> 
> > 
> > On 30 Mar 2006, at 19:43, Hans-Christian Armingeon wrote:
> > 
> > >My dom0 has 2g ram allocated, and I have 2.5 G Ram physically in my 
> > >machine.
> > >I needed more Ram in domU so I did a
> > 
> > If you don't start your domU with a 'mem=2G' or similar as a boot 
> > parameter then the domU will be unable to increase its memory 
> > allocation beyond its initial boot-time allocation. In this case, 'xm 
> > list' is lying to you -- it tells you what memory target the tools has 
> > asked the domU to aim for, not what the domU is currently using. :-)
> > 
> > That's my guess anyway -- the free memory reported by 'xm info' is 
> > definitely the truth, so 'xm list' is lying and that's probably the 
> > reason why. Take a look in the domU and see what it thinks. Also in the 
> > domU, look at the contents of /proc/xen/balloon.
> 
> Yes, that's right -- xm list shows the configured or requested memory, not the
> amount it's actually using.  Personally, I'd consider that a bug -- feel free
> to file it.
> 
> Ewan.
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
> 

-- 
jabber:johnny@wh-netz.de
icq:236971856

Re: xm info showing too much free ram

[Keir Fraser]

On 4 Apr 2006, at 11:44, Hans-Christian Armingeon wrote:

> Hello Keir,
>
> is it difficult to fix that?
>
> Maybe this is only a two liner.

I'm not sure. I doubt anyone's going to look at it right now so the 
best thing is to open a bug report so that the issue can be tracked.

  -- Keir