Re: [PATCH v3 04/10] hbitmap: drop meta bitmaps as they are unused

[Vladimir Sementsov-Ogievskiy]

20.01.2020 22:53, Eric Blake wrote:
> On 1/20/20 11:28 AM, Vladimir Sementsov-Ogievskiy wrote:
> 
>>>> I'm a bit not follow what you mean. I can just note, that dirty-bitmap.c
>>>> part of meta bitmaps was recently removed, and hbitmap.c part I forgot to
>>>> remove...
>>>
>>> Yes, but who used that dirty-bitmap.c interface?  As far as I can tell,
>>> nobody.
>>
>> Yes, as far as I know, nobody and never.
>>
>>>
>>>> Meta bitmaps were intended to control live migration of bitmaps and to
>>>> implement something like partial sync of bitmaps (write to qcow2 only
>>>> changed part of bitmap), but migration implemented in other way
>>>> (postcopy) and the second thing was not implemented.
>>>
>>> OK.  I was wondering why they were implemented without ever having been
>>> used (as far as I can tell).
>>>
>>
>> It was too optimistic preparatory series.
> 
> Matches my recollection (we had several ideas about how to tackle it; 
> meta-bitmaps was proposed as one idea and this code landed, but we never 
> actually finished that idea before a better one was actually coded, so this 
> has always been dead code).
> 
>>
>> (I can never finally understand, series - who a they or what is it?
>>    Plural or singular?
> 
> English is funny; "series" is one of the few words that works as both 
> singular and plural (another example is "sheep").

OK, thanks) Actually, Russian has such words too (штаны=pants, 
ножницы=scissors, interesting that first examples
which came in my mind has same feature in English too).

> 
>> They were too optimistic series? Sounds weird..
> 
> My spin: "The original series was too optimistic."
> 
>>    And if one series is series, than what about several serieses?
>>    OK, let's say, it was too optimistic preparatory patch set :)
>>
>>
> 


-- 
Best regards,
Vladimir