Bug 750704

Summary: disabled balloon size will work after enable balloon driver
Product: Red Hat Enterprise Linux 6 Reporter: langfang <flang>
Component: qemu-kvmAssignee: Amit Shah <amit.shah>
Status: CLOSED NOTABUG QA Contact: Virtualization Bugs <virt-bugs>
Severity: medium Docs Contact:
Priority: unspecified    
Version: 6.2CC: acathrow, amit.shah, bcao, berrange, bsarathy, juzhang, mkenneth, rhod, tburke, virt-maint, vrozenfe
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2011-12-09 11:59:09 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:

Description langfang 2011-11-02 05:46:08 UTC
Description of problem:
disabled balloon size will work after enable balloon driver

Version-Release number of selected component (if applicable):
kernel:2.6.32-214.el6.x86_64
qemu-kvm-0.12.1.2-2.206.el6.x86_64
virtio-win:virtio-win-1.4.0-1.el6.noarch.rpm


How reproducible:
100%
CLI:/usr/libexec/qemu-kvm -m 2G -smp 2 -cpu cpu64-rhel6,+x2apic -usb -device usb-tablet -rtc base=localtime,clock=host,driftfix=slew -drive file=/mnt/win2003R2sp2_x64.qcow2.bak,format=qcow2,if=none,id=drive-ide0-0-0,werror=stop,rerror=stop,cache=none -device virtio-blk-pci,drive=drive-ide0-0-0,id=ide0-0-0 -netdev tap,id=hostnet0,script=/etc/qemu-ifup -device virtio-net-pci,netdev=hostnet0,mac=00:10:20:2c:45:23,bus=pci.0,addr=0x4,id=net0 -boot order=dcn -uuid d2b0ab4c-d828-468e-8e30-ef5da1754db1 -rtc-td-hack -no-kvm-pit-reinjection -monitor stdio -name win2k3sp2-64 -drive file=/usr/share/virtio-win/virtio-win.iso,if=none,media=cdrom,id=drive-ide0-1-0,readonly=on,format=raw -device ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -device virtio-balloon-pci,bus=pci.0,id=balloon0 -spice port=5830,disable-ticketing -vga qxl


Steps to Reproduce:
1.boot a win2003 guest with balloon device(....-device
virtio-balloon-pci,bus=pci.0,id=balloon0),and disable balloon driver
2.set ballloon size
(qemu) balloon 1024
balloon: actual=2048
3.enable balloon driver
4.view the balloon size
(qemu) info balloon
balloon: actual=1024
  
Actual results:the balloon size  change to disabled balloon size


Expected results:the balloon size will not change


Additional info:

Comment 2 Ronen Hod 2011-11-02 06:27:35 UTC
Fang,
it looks almost like a duplicate of BZ#750695, but with a different summary.
Am I missing anything?
Regardless, it will be assigned to RHEL6.3
Thanks.

Comment 3 Mike Cao 2011-11-02 06:48:27 UTC
(In reply to comment #2)
> Fang,
> it looks almost like a duplicate of BZ#750695, but with a different summary.
> Am I missing anything?
> Regardless, it will be assigned to RHEL6.3
> Thanks.

I don't think it is a bug ,at least not a virtio-win bug . Because RHEL guest also hit this ,re-assign to qemu-kvm component and add amit in cc list .

Comment 4 Mike Cao 2011-11-02 06:50:53 UTC
*** Bug 750695 has been marked as a duplicate of this bug. ***

Comment 5 Vadim Rozenfeld 2011-11-02 08:14:36 UTC
(In reply to comment #3)
> (In reply to comment #2)
> > Fang,
> > it looks almost like a duplicate of BZ#750695, but with a different summary.
> > Am I missing anything?
> > Regardless, it will be assigned to RHEL6.3
> > Thanks.
> 
> I don't think it is a bug ,at least not a virtio-win bug . Because RHEL guest
> also hit this ,re-assign to qemu-kvm component and add amit in cc list .

Absolutely right. It's the expected behaviour by design.
Best,
Vadim.

Comment 6 Amit Shah 2011-12-09 11:32:55 UTC
I think this is a bug: management software may not come to know when a balloon value gets applied.  I think we should fix this.

The fix for bug 725621 will also fix this issue.  So unless there's any objection, I'll do this and mark this bug as a dup of the other one.

Comment 7 Daniel Berrangé 2011-12-09 11:50:41 UTC
> I think this is a bug: management software may not come to know when a balloon
> value gets applied.  I think we should fix this

That's not really a bug - it is a feature request.

Setting balloon target has always been disconnected from the actual applied balloon limit, so if you want to know the actual balloon value you have to explicitly query it when you want to know. The guest OS can change its actual balloon limit up or down at will.

It would, however, be useful if QMP has an async event to notify a mgmt application whenever the actual balloon level changes. This would avoid the need for the mgmt app to periodically poll 'query-balloon'.

Comment 8 Amit Shah 2011-12-09 11:59:09 UTC
Alright, I'll close this bug as NOTABUG then.