[dpdk-dev] [PATCH 0/3] generic channel for multi-process communication

[Burakov, Anatoly]

On 12-Dec-17 7:34 AM, Tan, Jianfeng wrote:
> Hi Anatoly,
> 
>> -----Original Message-----
>> From: Burakov, Anatoly
>> Sent: Monday, December 11, 2017 6:00 PM
>> To: Tan, Jianfeng; dev at dpdk.org
>> Cc: Richardson, Bruce; Ananyev, Konstantin; thomas at monjalon.net
>> Subject: Re: [PATCH 0/3] generic channel for multi-process communication
>>
>> On 30-Nov-17 6:44 PM, Jianfeng Tan wrote:
>>> This patchset adds a generic channel for multi-process (primary/secondary)
>>> communication.
>>>
>>> Patch 1: addess the purpose and howto;
>>> Patch 2: add a syncrhonous way for those messages which need a response
>> immediately.
>>> Patch 3: Rework vfio to use this generic communication channel.
>>>
>>
>> Hi Jianfeng,
>>
>> Just a general comment: I am assuming this has the limitation of
>> "everything happens through primary process's involvement". This will
>> work for VFIO, as secondary always needs to ask the primary before doing
>> anything, but it doesn't address other issues that could have been
>> addressed with IPC.
>>
>> For example, if a primary process would've hotplugged a device, it can't
>> notify all secondary processes about this; rather, it has to wait until
>> secondary processes ask for this info.
> 
> No need to wait the secondary to pull such info.
> 
> It can work like this:
> (1) Register a hotplug callback for each process at initialization;
> (2) Whenever a process wants to hotplug a device, it will broadcast the info, by broadcast, I mean:
>    - if plugin happens at the primary, the primary will tell all of the secondary processes;
>    - if plugin happens at one secondary, it will firstly tell the primary, and the primary will broadcast it to all the secondary process.
> 
>> Neither can it do anything if
>> secondary requests a primary to do something, and notify other secondary
>> processes about it (i.e. if secondary wants to hotplug a device, but
>> there are other secondaries also running). It would be great to have a
>> standard way of doing things like this in future revisions of our IPC.
> 
> Please review above thing; If you are OK with that, I'll include this in the next version.
> 
> Thanks,
> Jianfeng
> 
>>
>> --
>> Thanks,
>> Anatoly

Yes, that would work, my bad. However i don't think we necessarily need 
it right now. This can go in a separate patch. I was rather looking at 
other, future potential use cases, hotplug was just an example.

-- 
Thanks,
Anatoly