[Pkg-xen-devel] Bug#927071: Bug#927071: xen: More balloon-leak observation

[Hans van Kranenburg]

Hi,

On 4/22/19 1:10 AM, Elliott Mitchell wrote:
> Refering to this as "balloon-leak" as it looks sort of like a
> memory-leak, but is instead memory disappearing into the balloon.

I haven't heard about this symptom before your report.

> There are two things which have been happening more recently which may
> have exaggerated this problem.  First, one of the DomUs is acting as a
> fileserver and that has been getting more usage recently.  Second, I've
> been testing block-device hotplug as a mechanism to transfer data between
> VMs (xl block-detach from one VM, then xl block-attach to another VM).

Did you look at the numbers and see if it happens when you do this?

> The DomUs appear absolutely uneffected by this.  Even as Dom0 has gotten
> to a situation where `shutdown -r now` fails, the DomUs appear to be
> chugging away with no problems.
> 
> There is plenty of free memory for creating additional VMs (perhaps too
> much, and that confused Xen?), so this is really puzzling that memory is
> being ballooned away from Dom0.  At this point I plan after the next
> restart to double the allocation for Dom0 and see whether Dom0 is able
> to last more than a week.

Weird. Can you log memory stats over time, so that you can see when it
happens, and correlate it to other events?

Hans