OSPF performance/SPF calculations

[Joakim Tjernlund]

Ondrej Zajicek <santiago at crfreenet.org> wrote on 2010/04/23 12:01:29:
>
> On Fri, Apr 23, 2010 at 11:37:56AM +0200, Joakim Tjernlund wrote:
> > > realloc() is used only for a persistent buffer to grow it sufficiently
> > > large. So it is called only small number of times during the run of
> > > the program and not in subsequent LSA originations. Therefore it is
> > > not an issue.
> >
> > It would be better if you used the same (linear space) as you do
> > for received LSA's. I guess the received LSA's has a MAX size?
> > Then you could allocate space as big as the MAX received LSAs size,
> > add data to it and, if you want to, realloc the the whole
> > LSA to a smaller size.
>
> Received LSAs are copied from RX buffer to the space allocated for
> them. Originated LSAs are prepared in the persistent buffer and then
> copied to the space allocated for them. In both cases the final
> space for the LSA is allocated once (not reallocated) for the final
> size of the LSA.

I must be missing something then(not surprising as I just started looking
at BIRD). Why do you need the separate allocation for the body of the LSA then?
Why not just adding entries to the allocated LSA header?

    Jocke