Re: [dpdk-dev] [PATCH 10/12] vhost: support to kick in secondary process

["Tan, Jianfeng" <jianfeng.tan@intel.com>]

On 9/21/2017 11:33 AM, Yuanhan Liu wrote:
> Firstly, very sorry for so late review!

That is understood.

>
> On Fri, Aug 25, 2017 at 09:40:50AM +0000, Jianfeng Tan wrote:
>> To support kick in secondary process, we propose callfd_pri and
>> kickfd_pri to store the value in primary process; and by a new
>> API, rte_vhost_set_vring_effective_fd(), we can set effective
>> callfd and kickfd which can be used by secondary process.
>>
>> Note in this case, either primary process or the secondary process
>> can kick the frontend; that is, they cannot kick a vring at the
>> same time.
> Since only one can work, why not just overwriting the fd? Say, you
> could introudce some APIs like "rte_vhost_set_vring_callfd", then
> you don't need to introduce few more fields like "callfd_pri".

That cannot address the below case:
1. Primary starts;
2. Secondary one starts; (if we overwrite it without storing it in some 
other fields)
3. Secondary one exits;
4. Secondary two starts. (primary cannot share the fd with this 
secondary process now, as this fd does not mean anything to the primary 
process)

Thanks,
Jianfeng