Re: [PATCH v3 2/7] migration: Implement switchover ack logic

[Avihai Horon <avihaih@nvidia.com>]

On 25/05/2023 15:44, Peter Xu wrote:
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>
> On Thu, May 25, 2023 at 12:51:46PM +0300, Avihai Horon wrote:
>> However, there is one issue -- we can't send the ACK up here [1], as at that
>> point the return path has not been created yet.
>> A possible solution is to check for mis->switchover_ack_pending_num == 0
>> when we create the return path and send the ACK there.
>> It's not as clean as checking the number of users and ACKing here in the
>> same place, but it works.
>>
>> Do you think it's OK? or do you have another idea?
> Good point. It looks fine to me as we create the return path mostly at the
> very early stage right after the migration headers.
>
> Let's just add a comment describing the ordering fact?  IMHO it's about
> switchover_ack_pending_num won't be used before setup of the return path
> due to current wire protocol (we create return path before sending mostly
> anything else), so setup it there is fine.

Sure, I will also add a comment.

Thanks.