balloon only resizes by 2M

[Michael Thomas]

when in monitor and running balloon 512 from a 1024M VM, the vm dropped the size to 1020 (this value changes), then every subsequent request to balloon 512 will drop it by another 2M. The system was running at above 60% RAM free when these requests were made. also requesting to up the ram results in no change above 1024 (I'm guessing this is intentional, but was unable to find any documentation)

Versions:

qemu-kvm 0.13.0
qemu-kvm.git b377474e589e5a1fe2abc7b13fafa8bad802637a

Qemu Command Line:

./x86_64-softmmu/qemu-system-x86_64 -drive file=/var/machines/seven.base,if=virtio -net nic,model=virtio,macaddr=02:00:00:00:00:01 -net tap,script=/etc/qemu/qemu-ifup,downscript=/etc/qemu/qemu-ifdown -vga std -usb -usbdevice tablet -rtc base=localtime,clock=host -watchdog i6300esb -balloon virtio -m 1024 -no-quit -smp 2 -monitor stdio

Monitor Session:

QEMU 0.13.50 monitor - type 'help' for more information
(qemu) info balloon
balloon: actual=1024
(qemu) balloon 1536
(qemu) info balloon
balloon: actual=1024
(qemu) balloon 512
(qemu) info balloon
balloon: actual=1020
(qemu) info balloon
balloon: actual=1020
(qemu) balloon 512
(qemu) info balloon
balloon: actual=1018

[a1bert (a1bert)]

the same here:

host debian squeeze: qemu-kvm-0.12.5
guest: windows 2008 server
balloon driver: 6.1.7600.16385 10.8.2010

~# virsh -c qemu:///system dominfo 9 | grep Used
Used memory: 2064384 kB
~# virsh -c qemu:///system setmem 9 512000

~# virsh -c qemu:///system dominfo 9 | grep Used
Used memory: 2062336 kB

the same host, but winXP guest with the same balloon driver is working, looks like balloon driver issue...

[Thomas Huth (th-huth)]

Triaging old bug tickets ... can you still reproduce this issue with the latest version of QEMU / the latest version of the balloon driver in the guest?

[Launchpad Janitor (janitor)]

[Expired for QEMU because there has been no activity for 60 days.]