Re: Actual dom0 memory much lower than dom0_mem setting

[Andy Smith <andy@xxxxxxxxxxxxxx>]

Hi Jürgen,

On Wed, Apr 08, 2026 at 09:21:48AM +0200, Jürgen Groß wrote:
> On 03.04.26 17:23, Andy Smith wrote:
> > $ sudo xl info | grep xen_commandline
> > xen_commandline        : placeholder dom0_mem=8192M dom0_max_vcpus=2 
> > com1=115200,8n1,0x2f8,10 console=com1,vga ucode=scan smt=1
> > $ free -m
> >                total        used        free      shared  buff/cache   
> > available
> > Mem:           6285        1425        3239         126        1620        
> > 4642
> > Swap:           952           1         951
> > 
> > Is this widely know and expected?
> > 
> > Is it fixable?
> > 
> > Is it something you can calculate? ("To get 8192M usable dom0 memory I
> > must specify…").
> 
> Some questions:
> 
> I would assume the memory size as reported by "xl list" is the configured one?

Yes.

$ sudo xl list
Name                                        ID   Mem VCPUs      State   Time(s)
Domain-0                                     0 10429     2     r-----   42170.5
$ sudo xl info | grep xen_commandline
xen_commandline        : placeholder dom0_mem=10429M dom0_max_vcpus=2 
com1=115200,8n1,0x2f8,10 console=com1,vga ucode=scan smt=1 no-real-mode edd=off

> What does "cat /proc/iomem" in dom0 report?
> 
> Could you please post the output of "dmesg" after boot?

Please find attached,

Thanks,
Andy

Attachment: iomem.txt
Description: Text document

Attachment: dmesg.txt
Description: Text document