Re: [Xen-devel] Dynamic Memory Management and Migration (3.0.4-0)

[Timo Benk <timo.benk@xxxxxx>]

Daniel P. Berrange wrote:
> On Wed, Jan 31, 2007 at 04:29:25PM +0100, Timo Benk wrote:
>> Hello,
>>
>> i noticed the following Problem:
>>
>> if i want to allow dynamic memory management of Linux-domains, i need to
>> set the following kernel parameter. Otherwise it is not possible, to
>> increase the memory of the domain above the initial assigned value:
>>
>> extra = "mem=10240M"
> 
> That should not be neccessary. We fixed the Hypervisor to implement the
> neccessary magic so that XenD can utilize the 'maxmem' parameter in
> guest config files correctly So for example
> 
>   mem=500
>   maxmem=800
> 
> Will make the guest VM boot up with 500 MB of initial RAM. It will also
> tell it to allocate page tables entries big enough to address 800 MB of
> RAM. So after boot up, you will be able to balloon the guest upto this
> maxmimum of 800 MB simply using 'xm mem-set 800'.
A quick test with 3.0.4-0 does not work on my side. I will try it again
tomorrow with 3.0.4-1. I dunno when the patch was applied to the xen source.

Her is what i have tried:

Domain-0:~ # xm create /etc/xen/vm/xendom1 -n
Using config file "/etc/xen/vm/xendom1".
(vm
    (name xendom1)
    (memory 256)
    (maxmem 512)
    (vcpus 1)
    (on_xend_start ignore)
    (on_xend_stop ignore)
    (cpu_cap 100)
    (cpu_weight 100)
    (image
        (linux
            (kernel /boot/vmlinuz-2.6.16.33-xenU)
            (ramdisk /boot/initrd-2.6.16.33-xenU)
            (root '/dev/sda1 ro')
        )
    )
    (device (vbd (uname phy:/dev/xenvol/xendom1_root) (dev sda1) (mode w)))
    (device (vbd (uname phy:/dev/xenvol/xendom1_swap) (dev sda2) (mode w)))
    (device (vif (mac 00:11:25:67:30:65)))
)

Domain-0:~ # xm create /etc/xen/vm/xendom1
Using config file "/etc/xen/vm/xendom1".
Started domain xendom1

Domain-0:~ # xm list
Name                                      ID   Mem VCPUs      State   Time(s)
Domain-0                                   0  2265     1     r-----   4834.5
xendom1                                    6   256     1     -b----      4.3

Domain-0:~ # xm mem-set xendom1 300
Domain-0:~ # xm list
Name                                      ID   Mem VCPUs      State   Time(s)

Domain-0                                   0  2265     1     r-----   4835.2
xendom1                                    6   257     1     ------     13.1

Domain-0:~ # ssh root@xxxxxxxxxxxx
Last login: Wed Jan 31 23:56:00 2007 from 172.17.0.1
xendom1:~ # free
             total       used       free     shared    buffers     cached
Mem:        262384     108404     153980          0       5840      63840
-/+ buffers/cache:      38724     223660
Swap:       524280          0     524280

xendom1:~ # logout
Connection to 172.17.0.101 closed.

Domain-0:~ # xm mem-set xendom1 400
Domain-0:~ # ssh root@xxxxxxxxxxxx
Last login: Wed Jan 31 23:56:08 2007 from 172.17.0.128
xendom1:~ # free
             total       used       free     shared    buffers     cached
Mem:        262384     108908     153476          0       6388      63812
-/+ buffers/cache:      38708     223676
Swap:       524280          0     524280
xendom1:~ #


Greetings,
-timo
-- 
Timo Benk - Jabber ID: fry@xxxxxxxxxxxx - ICQ ID: #414944731
PGP Public Key: http://m28s01.vlinux.de/timo_benk_gpg_key.asc


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