Re: MP-safe ifnet with psz & psref

[Joerg Sonnenberger <joerg%bec.de@localhost>]

On Fri, May 20, 2016 at 12:15:10PM +0900, Ryota Ozaki wrote:
> > Mbufs are slightly different. They can be queued on an interface for a
> > moderately long time. For this purpose, a "flush" hook would definitely
> > be needed. I think having such a hook would be useful for other purposes
> > as well, i.e. to trigger memory compaction. But it is a somewhat
> > expensive change in that it requires review of a lot of code.
> >
> > The final question for me is whether we can get away with just not
> > deallocating ifnet instances. Reusing them is fine in principle, the
> > problem is just keeping the memory type safe.
> 
> What "keeping the memory type safe" means?

Once allocated as ifnet, it will always be an ifnet.

> The problem "when we can reuse it?" seems to be similar to "when we can
> deallocate it?". Don't we need to do a similar solution I propose?

The big question is what do we use rcvif for. If it is just a cookie
used for preventing cycles, it doesn't matter what the content is.
Otherwise we should have a field whether it was initialized completely
or not.

Joerg