[libvirt] Memory Ballooning for VM Issue

[xuanmao_001]

Hi, I have some problems with qemu ballooning.

I saw the qemu docs. I found the qemu monitor command "balloon" that can request VM to change its memory allocation to value(in MB).
it requested qemu command line with "-balloon virtio", then I start qemu into monitor mode with memory 512MB.
first show balloon information.
(qemu) info balloon
(qemu)balloon: actual=512
the command above if like this, I think the balloon device worked fine.

(qemu) balloon 400
there was no error when I executed this command.
but when I executed "info balloon", the result was still 512. 
Is there something wrong?
please give me some ideas.

thanks.

qemu-kvm version: 1.0.1
linux kernel version: 3.1.6
 




xuanmao_001
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/libvir-list/attachments/20120807/573bac44/attachment-0001.htm>