PoD with Windows Balloon

PoD with Windows Balloon

[Chu Rui]

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Hi,
I have tried PoD in Windows/HVM. My VMM is XEN 4.0.0, Domain0 is RHEL
5.4/kernel 2.6.31, and DomainU is Windows 2003.
It does not work well as in Linux/HVM. The primary problem looks in the
balloon driver, which was obtained from
http://xenbits.xensource.com/ext/win-pvdrivers.hg

In my configuration, memory=512M, and maxmem=2G. After booted, I want to
inflate the balloon with the target=390M, but the balloon driver does not
work correctly.
It becomes clear after I get the debug messges from the balloon driver as
this:

00000000 0.00000000 XenPCI --> XenPci_BalloonHandler
00000001 0.00153629 XenPCI     target memory value = 390 (400000)
00000002 0.00619057 XenPCI <-- XenPci_BalloonHandler
00000003 0.00619715 XenPCI     Got balloon event, current = 512, target =
390
00000004 0.00858740 XenPCI     Trying to give 122 MB to Xen
00000005 0.00968578 XenPCI     Calling
HYPERVISOR_memory_op(XENMEM_decrease_reservation) - pfn_count = 256
00000006 0.02019652 XenPCI     decreased 256 pages
......

Obviously, the balloon driver thinks that the system has(target) only 512M
memory when booted, thus the balloon size was 122MB, not 2G-390M. Is it a
bug of the Windows balloon driver? Does it work if I simply modify the
source code to make the initial target value as 2G?

Thanks.

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Re: PoD with Windows Balloon

[George Dunlap]

It looks like possibly the GPLPV baloon driver is using the wrong value 
to calculate how much memory it's starting with (and thus how big it 
needs to make the balloon)?

The Citrix Windows PV drivers (which you can get free-as-in-beer from 
the XCP distribution) work properly with PoD on open-source last time I 
checked (probably a month ago).

  -George

On 30/11/10 11:05, Chu Rui wrote:
> Hi,
> I have tried PoD in Windows/HVM. My VMM is XEN 4.0.0, Domain0 is RHEL
> 5.4/kernel 2.6.31, and DomainU is Windows 2003.
> It does not work well as in Linux/HVM. The primary problem looks in the
> balloon driver, which was obtained from
> http://xenbits.xensource.com/ext/win-pvdrivers.hg
> In my configuration, memory=512M, and maxmem=2G. After booted, I want to
> inflate the balloon with the target=390M, but the balloon driver does
> not work correctly.
> It becomes clear after I get the debug messges from the balloon driver
> as this:
> 00000000 0.00000000 XenPCI --> XenPci_BalloonHandler
> 00000001 0.00153629 XenPCI     target memory value = 390 (400000)
> 00000002 0.00619057 XenPCI <-- XenPci_BalloonHandler
> 00000003 0.00619715 XenPCI     Got balloon event, current = 512, target
> = 390
> 00000004 0.00858740 XenPCI     Trying to give 122 MB to Xen
> 00000005 0.00968578 XenPCI     Calling
> HYPERVISOR_memory_op(XENMEM_decrease_reservation) - pfn_count = 256
> 00000006 0.02019652 XenPCI     decreased 256 pages
> ......
> Obviously, the balloon driver thinks that the system has(target) only
> 512M memory when booted, thus the balloon size was 122MB, not 2G-390M.
> Is it a bug of the Windows balloon driver? Does it work if I simply
> modify the source code to make the initial target value as 2G?
> Thanks.

RE: PoD with Windows Balloon

[Paul Durrant]

The balloon driver should read memory/static-max and memory/target from xenstore. The balloon size should be the former minus the latter.

  Paul

> -----Original Message-----
> From: George Dunlap
> Sent: 30 November 2010 11:15
> To: Chu Rui
> Cc: Xen-devel@lists.xensource.com; James Harper; Paul Durrant
> Subject: Re: PoD with Windows Balloon
> 
> It looks like possibly the GPLPV baloon driver is using the wrong
> value
> to calculate how much memory it's starting with (and thus how big it
> needs to make the balloon)?
> 
> The Citrix Windows PV drivers (which you can get free-as-in-beer
> from
> the XCP distribution) work properly with PoD on open-source last
> time I
> checked (probably a month ago).
> 
>   -George
> 
> On 30/11/10 11:05, Chu Rui wrote:
> > Hi,
> > I have tried PoD in Windows/HVM. My VMM is XEN 4.0.0, Domain0 is
> RHEL
> > 5.4/kernel 2.6.31, and DomainU is Windows 2003.
> > It does not work well as in Linux/HVM. The primary problem looks
> in the
> > balloon driver, which was obtained from
> > http://xenbits.xensource.com/ext/win-pvdrivers.hg
> > In my configuration, memory=512M, and maxmem=2G. After booted, I
> want to
> > inflate the balloon with the target=390M, but the balloon driver
> does
> > not work correctly.
> > It becomes clear after I get the debug messges from the balloon
> driver
> > as this:
> > 00000000 0.00000000 XenPCI --> XenPci_BalloonHandler
> > 00000001 0.00153629 XenPCI     target memory value = 390 (400000)
> > 00000002 0.00619057 XenPCI <-- XenPci_BalloonHandler
> > 00000003 0.00619715 XenPCI     Got balloon event, current = 512,
> target
> > = 390
> > 00000004 0.00858740 XenPCI     Trying to give 122 MB to Xen
> > 00000005 0.00968578 XenPCI     Calling
> > HYPERVISOR_memory_op(XENMEM_decrease_reservation) - pfn_count =
> 256
> > 00000006 0.02019652 XenPCI     decreased 256 pages
> > ......
> > Obviously, the balloon driver thinks that the system has(target)
> only
> > 512M memory when booted, thus the balloon size was 122MB, not 2G-
> 390M.
> > Is it a bug of the Windows balloon driver? Does it work if I
> simply
> > modify the source code to make the initial target value as 2G?
> > Thanks.