Re: [PATCH v2 21/29] migration/multifd: Add pages to the receiving side

[Fabiano Rosas]

Peter Xu <peterx@redhat.com> writes:

> On Wed, Nov 01, 2023 at 02:20:32PM -0300, Fabiano Rosas wrote:
>> I wonder if adapting multifd to use a QIOTask for the channels would
>> make sense as an intermediary step. Seems simpler and would force us to
>> format multifd in more generic terms.
>
> Isn't QIOTask event based, too?
>
> From my previous experience, making it not gcontext based, if we already
> have threads, are easier.  But maybe I didn't really get what you meant.

Sorry, I wasn't thinking about the context aspect. I agree it's easier
without it.

I was talking about having standardized dispatch and completion code for
multifd without being a whole thread pool. So just something that takes
a function and a pointer to data, runs that in a thread with some
locking and returns in a sane way. Every thread we create in the
migration code has a different mechanism to return after an error and a
different way to do cleanup. The QIOTask seemed to fit that at a high
level.

I would be happy with just the return + cleanup part really. We've been
doing work around those areas for a while. If we could reuse generic
code for that it would be nice.