Re: [uq/master patch 2/5] kvm: add logging count to slots

[Jan Kiszka <jan.kiszka@web.de>]

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Avi Kivity wrote:
> On 04/25/2010 04:57 PM, Jan Kiszka wrote:
>>
>>> It's still a good idea.  The current API assumes that there will be only
>>> one slot-based client (or that multiple clients will keep the refcount
>>> themselves).
>>>
>>> After the bytemap ->  multiple bitmaps conversion this can be
>>> extended to
>>> each client getting its own bitmap (and therefore, s/refcount/list of
>>> bitmaps/ and s/!refcount/list_empty()/).
>>>
>>>      
>> No concerns if
>>   - there is an existing use case for multiple clients, at least in
>>     qemu-kvm
>>    
> 
> There isn't.  But I don't like hidden breakage.

It's (so far) an unproblematic API property we can document. I don't
like changing APIs just for "there might be the case that...".

> 
>>   - the logging API is consistently converted, not just extended
>>     (IOW, migration_log is converted to logging_count)
>>    
> 
> migration_log needs to remain global, since we want hotplug memory to
> autostart logging.

Can't follow yet, what will be the usage pattern of
kvm_set_migration_log? Or would the hotplug code require a separate
interface? Is it already the multi-client use case I'm looking for?

> 
>>   - someone signs he checked that current use of start/stop in qemu is
>>     completely symmetrical (I think to remember this used to be not the
>>     case, but I might be wrong)
>>    
> 
> I remember this too.  Marcelo?
> 

Jan


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