Re: [PATCH] xend: Fix xm list bug reporting incorrect memory size

["Marcos E. Matsunaga" <Marcos.Matsunaga@oracle.com>]

Hi Ian,

Sorry, I thought I sent you the answer before, but it was stuck in my 
drafts folder for some reason.

I am not very familiar with xend either, but after reading the code, my 
understanding is that when a domain is being created, it keeps the 
domain paused until all the resources are allocated, then it unpause it 
to complete the boot. If I made a wrong assumption, please correct me.

If dominfo is called during the domain initialization process with 
update_mem = true (The default for update_mem is false), it will return 
zero as the resource is not allocated yet, and that will break the 
initialization process. Also, I don't think it would make sense to 
update memory information of a domain that is paused.

That's the relevance of the domain being paused.

Regards,

Marcos Eduardo Matsunaga

Oracle USA
Linux Engineering

“The statements and opinions expressed here are my own and do not
necessarily represent those of Oracle Corporation.”

On 04/08/2013 01:06 PM, Ian Jackson wrote:
> Konrad Rzeszutek Wilk writes ("[Xen-devel] [PATCH] xend: Fix xm list bug reporting incorrect memory size"):
>> From: Marcos Matsunaga<Marcos.Matsunaga@oracle.com>
>>
>> Make sure memory is updated every time XendConfig.update is called.
>>
>> Without this patch, if a guest self-balloons, the amount of memory
>> that 'xend' thinks the guest is using is based on last cached value.
>> This means the reported value is nowhere close to what the real
>> value is.
> Err, right.  I'm afraid I'm very unfamiliar with the xend code so this
> is going to take more explanation than usual.
>
>> -        self._dominfo_to_xapi(dominfo)
>> +	if dominfo['paused']:
>> +           self._dominfo_to_xapi(dominfo)
>> +        else:
>> +           self._dominfo_to_xapi(dominfo, update_mem = True)
> Can you explain what the relevance is of the domain being paused ?
>
> Thanks,
> Ian.


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