[dm-devel] [PATCH] nvme: allow ANA support to be independent of native multipathing

[Hannes Reinecke]

On 11/16/18 10:49 AM, Christoph Hellwig wrote:
> On Fri, Nov 16, 2018 at 10:40:40AM +0100, Hannes Reinecke wrote:
>>>> Introduce ability to always re-read ANA log page as required due to ANA
>>>> error and make current ANA state available via sysfs -- even if native
>>>> multipathing is disabled on the host (e.g. nvme_core.multipath=N).
>>>
>>> The first part I could see, but I still want to make it conditional
>>> in some way as nvme is going into deeply embedded setups, and I don't
>>> want to carry the weight of the ANA code around for everyone.
>>>
>> Can you clarify this a bit?
>> We _do_ have the NVME multipath config option to deconfigure the whole
>> thing during compile time; that isn't influenced with this patch.
>> So are you worried about the size of the ANA implementation itself?
>> Or are you worried about the size of the ANA structures?
> 
> I just see the next step of wanting to move ANA code into the core
> which is implied above.

Really, I couldn't care less _where_ the ANA code lives.
If the size of which is any concern we can even make it configurable of 
sorts.

>>
>>> The second I fundamentally disagree with.  And even if you found agreement
>>> it would have to be in a separate patch as it is a separate feature.
>>>
>> Why? Where's the problem with re-reading the ANA log pages if we get an
>> event indicating that we should?
> 
> "second" here means the sysfs file.
> 
Ok, so would you be happy with making ANA support configurable?

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		   Teamlead Storage & Networking
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