Re: [RFC PATCH v2 1/6] migration/multifd: Remove channels_ready semaphore

[Peter Xu]

On Fri, Oct 20, 2023 at 09:48:54AM -0300, Fabiano Rosas wrote:
> > If pending_job == 0 -> owner of the channel is migration_thread and it
> > can use it.
> >
> > If pending_job > 0 -> owner of the channel is the channel thread and
> > migration_thread can't use it.
> 
> Do you really mean "migration_thread" here or just multifd_send_pages()?
> Because multifd_send_sync_main() doesn't care about this ownership
> rule. Does that mean that code is incorrect?

Yes, that's also what I was referring as the confusion, too.

[...]

> It's a semantic issue really, but I'd rather we avoid locking ourselves
> more into the "pages" idea for multifd threads. The data being sent by
> the multifd thread should be opaque.

I've put these ideas into a RFC patchset here:

[PATCH RFC 0/7] migration/multifd: quit unitifications and separate sync packet

I kept it "pending_job" there, avoid using "pages" as a name.

Fabiano, I have a patch there that dropped p->quit, so there will be
crossovers with your patchset.  I tried to leave that alone, but found I'd
better clean that up when add the send thread helpers.  Let's see how it
goes..

Thanks,

-- 
Peter Xu