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Re: [Xen-users] Ballooning and Free memory in xm info

To: Mark Williamson <mark.williamson@xxxxxxxxxxxx>
Subject: Re: [Xen-users] Ballooning and Free memory in xm info
From: Stefan de Konink <skinkie@xxxxxxxxx>
Date: Sat, 19 Jul 2008 18:30:46 +0200
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Mark Williamson schreef:
On Saturday 19 July 2008, Stefan de Konink wrote:
Is it expected behavior that when ballooning is enabled the amount of
free memory visisble is 28k (thus: 0) in free_memory?

Do you mean autoballooning of dom0? Before you've started and destroyed any guests then I'd guess this is normal - dom0 will have been sized to use all available memory. From Xen's PoV the memory is not free because dom0 currently owns it; dom0 will free it to Xen before starting a domU when autoballooning is active.

Or did you mean something else?

Even with one domain active it is still 0. I'm currently creating an cluster economy. One part of the bidding process is new domain is of course free memory. I'm using libvirt, and this is 'smartly' reporting only 28k free memory with ballooning on. That is probably equal to xm info does in megabytes.

I have 'solved' the issue by specifying dom0_mem=... at the Xen cmdline, but I guess there must be a way to get the value:

total_free = xen_total - (dom0_total - dom0_free)

(from the ballooning driver)


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