Re: [PATCH 2.4] backport neighbour cache redesign

["David S. Miller" <davem@xxxxxxxxxxxxx>]

On Mon, 4 Oct 2004 23:11:58 +0200
Harald Welte <laforge@xxxxxxxxxxxx> wrote:

> yes, I remember that email.  I didn't think further about it, since I
> got the feeling that there is significant movement to get rid of the
> neighbour cache at some point (if/when there is some fast lookup
> algorithm implemented) - and if we look at ipv6, there is no routing
> cache.

Another idea is to dynamically grow the thresholds based upon usage
just as we do for the hash tables.  For example, if we find say %90
of neighbour entries in-use at forced GC time, we increment the
thresholds by some factor.

Note that the "in-use" part is very important, it prevents a DoS
spam from growing the neighbour cache since such traffic causes
neighbour entries to quickly become unused.