Re: [1/1] connector/CBUS: new messaging subsystem. Revision numbernext.

[Evgeniy Polyakov]

On Tue, 26 Apr 2005 22:10:26 +0400
Evgeniy Polyakov <johnpol@xxxxxxxxxxx> wrote:

> > > > There may not be the same work with different data.
> > > > 
> > > 
> > > Ugh, that really blows. Now every user of a particular message type
> > > has to coordinate efforts with other users of the same message type...
> > > 
> > > Imability to "fire and forget" undermines usefulness of whole
> > > connector. How will you for example implement hotplug notification
> > > over connector? Have kobject_hotplug wait and block other instances?
> > > But wait on what?
> > 
> > This is a simple load balancing schema.
> > Netlink messages may be dropped in socket queue when 
> > they are bing delivered to userspace - this is the same - 
> > if work queue can not be scheduled, message will be dropped,
> > but in this case userspace also can not be scheduled
> > and message will be dropped.
> 
> Btw, I belive we see that it is reverse direction...
> So we have reverse load balancing schema here - 
> exactly like userspace socket queueing.
> We basically can not sleep here - it will be DOS.

And yet another btw - netlink is unreliable protocol,
that is why there are seq and ack fields in connector's header - 
connector's users must implement some check on top of
raw connector messages - it could be returned message with
timeout resending and so on.
I wrote it several times and it is in connector's documentation.

	Evgeniy Polyakov

Only failure makes us experts. -- Theo de Raadt
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