Mailing List Archive: Can't increase memory size during runtime

Can't increase memory size during runtime

Jun 28, 2005, 6:47 AM

Post #1 of 4 (435 views)

Hi,

I thought it would be possible to increase the size of running domU
using "xm balloon" but I can only change the memory up to the value
specified in config file (the initial memory size).

Maybe I'm doing something wrong or I am missing something? What a tried:

dev (3) is the domU is used for testing in this case but it is not
limited to this domU - it happends for all of them...

nd:/etc/network# xm list
Name Id Mem(MB) CPU State Time(s) Console
Domain-0 0 27 0 r---- 18.0
bb1 2 63 0 -b--- 6.6 9602
dev 3 127 0 -b--- 1.7 9603

The machine has 512M memory so there should be some memory left to use:

nd:/etc/network# xm info
system : Linux
host : nd
release : 2.6.11.10-xen0
version : #2 Fri Jun 24 21:24:58 CEST 2005
machine : i686
cores : 1
hyperthreads_per_core : 1
cpu_mhz : 2392
memory : 503
free_memory : 201

So in theory it be possible to increase the memory by around 200MB...
Lets try to 128M from this and give "dev" a total memory of 256:

nd:/etc/network# xm balloon dev 256
nd:/etc/network# xm list
Name Id Mem(MB) CPU State Time(s) Console
Domain-0 0 27 0 r---- 18.5
bb1 2 63 0 -b--- 6.6 9602
dev 3 127 0 -b--- 1.7 9603

Hmmmm... this didn't worked... Host has still 128M... "xm info" also
gives same results as before.

I'm using 2.6.11.10 kernel and Xen 2.0.5 - all domains running debian
sarge. If somebody has an idea about that - would be great! Workaround
seems to be to start a domain with 256M and decrease it soon to eg.
128M. Increasing the size works than...

Regards,
Patrick

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Re: Can't increase memory size during runtime [ In reply to ]

posi at posi

Jun 28, 2005, 7:54 AM

Post #2 of 4 (428 views)

Permalink

Hi again,

just a couple of minutes after sending my first mail to the list I found
the "xm maxmem" command. Expected this to be the solution - but it is
not... It's not working like expected - or, like I expected ;)

Starting with 128M memory for domain "dev" which was bootet with 256M
and then decreased to 128M:

nd:~# xm list
Name Id Mem(MB) CPU State Time(s) Console
Domain-0 0 27 0 r---- 46.6
bb1 2 63 0 -b--- 7.1 9602
dev 5 127 0 -b--- 4.5 9605

Ok, let's increase memory:

nd:~# xm maxmem dev 256
nd:~# xm balloon dev 200
nd:~# xm list
Name Id Mem(MB) CPU State Time(s) Console
Domain-0 0 27 0 r---- 47.6
bb1 2 63 0 -b--- 7.1 9602
dev 5 127 0 -b--- 4.5 9605

Nothing happend :-((

nd:~# xm info
system : Linux
host : nd
release : 2.6.11.10-xen0
version : #2 Fri Jun 24 21:24:58 CEST 2005
machine : i686
cores : 1
hyperthreads_per_core : 1
cpu_mhz : 2392
memory : 503
free_memory : 202
nd:~#

And still around 200M left -- so increasing from 128 to 200 should fine....

Regards,
Patrick

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Re: Can't increase memory size during runtime [ In reply to ]

hai at cs

Jul 6, 2005, 10:12 PM

Post #3 of 4 (424 views)

Permalink

On Tue, 28 Jun 2005, Patrick Hess wrote:

>
> Hi again,
>
> just a couple of minutes after sending my first mail to the list I found
> the "xm maxmem" command. Expected this to be the solution - but it is
> not... It's not working like expected - or, like I expected ;)
>
> Starting with 128M memory for domain "dev" which was bootet with 256M
> and then decreased to 128M:

Can you explain more about "booted with 256M and then decreased to 128M"?
Do you mean you add "mem=268435456" as the kernel command line parameter
as well as a line "memory=128" in domain "dev"'s configuration file before
you create the "dev" domain? In another word, the "dev" domain's config
file should look like the following according to the instructions
suggested in
http://lists.xensource.com/archives/html/xen-users/2005-04/msg00294.html:

...
name="dev"
memory = 128
root = "/dev/sda1 ro"
extra = "mem=268435456"
...

> nd:~# xm list
> Name Id Mem(MB) CPU State Time(s) Console
> Domain-0 0 27 0 r---- 46.6
> bb1 2 63 0 -b--- 7.1 9602
> dev 5 127 0 -b--- 4.5 9605
>
> Ok, let's increase memory:
>
> nd:~# xm maxmem dev 256
> nd:~# xm balloon dev 200
> nd:~# xm list
> Name Id Mem(MB) CPU State Time(s) Console
> Domain-0 0 27 0 r---- 47.6
> bb1 2 63 0 -b--- 7.1 9602
> dev 5 127 0 -b--- 4.5 9605
>
> Nothing happend :-((
>
> nd:~# xm info
> system : Linux
> host : nd
> release : 2.6.11.10-xen0
> version : #2 Fri Jun 24 21:24:58 CEST 2005
> machine : i686
> cores : 1
> hyperthreads_per_core : 1
> cpu_mhz : 2392
> memory : 503
> free_memory : 202
> nd:~#
>
> And still around 200M left -- so increasing from 128 to 200 should fine....
>
> Regards,
> Patrick
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
>

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Re: Can't increase memory size during runtime [ In reply to ]

posi at posi

Jul 13, 2005, 2:17 AM

Post #4 of 4 (424 views)

Permalink

Xuehai Zhang wrote:

>> Starting with 128M memory for domain "dev" which was bootet with 256M
>> and then decreased to 128M:
>
>
> Can you explain more about "booted with 256M and then decreased to 128M"?
> Do you mean you add "mem=268435456" as the kernel command line parameter
> as well as a line "memory=128" in domain "dev"'s configuration file before
> you create the "dev" domain? In another word, the "dev" domain's config

Hi,

I started by setting memory=256 and mem=268435456, after booting I used

$ xm balloon dev 128

to decrease. Then I have 256M available at the domU and I can decrease
to any value that I like.

> name="dev"
> memory = 128
> root = "/dev/sda1 ro"
> extra = "mem=268435456"

Starting domU with this memory settings gives me 128M initial memory but
increasing the memory to any value between 128M and 256M show no
reaction while "xm list" still shows me 233 M available... :(

Regards,
Patrick

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