Re: [Qemu-devel] [RFC PATCH RDMA support v5: 03/12] comprehensive protocol documentation

["Michael R. Hines" <mrhines@linux.vnet.ibm.com>]

On 04/15/2013 09:30 AM, Paolo Bonzini wrote:
> Il 15/04/2013 15:24, Michael R. Hines ha scritto:
>> Now, in this example, let's say the migration starts up and the hypervisor
>> has run out of physical memory and starts swapping during the migration.
>> (also for the sake of argument).
>>
>> The next thing that would immediately happen is the
>> next IB verbs function call: "ib_reg_mr()".
>>
>> This function call would probably fail because there's nothing else left
>> to pin and the function call would return an error.
>>
>> So my question is: Is it not sufficient to send a message back to the
>> primary-VM side of the connection which says:
>>
>> "Your migration cannot proceed anymore, please resume the VM and try
>> again somewhere else".
>>
>> In this case, both the system administrator and the virtual machine are safe,
>> nothing has been killed, nothing has crashed, and the management software
>> can proceed to make a new management decision.
>>
>> Is there something wrong with this sequence of events?
> I think it's good enough.  "info migrate" will then report that
> migration failed.
>
> Paolo
>

Ok, that's good. So the current patch "[PATCH v2] rdma" is not handling this
particular error condition properly, so that's a bug.

I'll send out a trivial patch to fix this after the pull along with all 
the other
documentation updates we have discussed.

- Michael