Re: [PATCH v5 3/3] migration: process_incoming_migration_co(): move colo part to colo

[Juan Quintela <quintela@redhat.com>]

Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> wrote:
> Let's make better public interface for COLO: instead of
> colo_process_incoming_thread and not trivial logic around creating the
> thread let's make simple colo_incoming_co(), hiding implementation from
> generic code.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>

Reviewed-by: Juan Quintela <quintela@redhat.com>

Independent of this patch, I still wonder if moving incoming migration
from a coroutine to a thread makes sense.  On one hand:

- it would simplify (a bit) the already complex code
- it would make a bit better in non-multifd migrations, right now, if we
  put enough networking, the botleneck is the migration incoming
  coroutine.

On the other hand:
- We would have to work with bottom handlers (as the outgoing migration
  does)
- With multifd enabled, the amount of data that is sent through the
  main migration channel is just a few MB, so not that it is going to
  improve a lot.

So, it is not clear to me what to do here.

Later, Juan.