On 26.08.2013 16:46, Luigi Rizzo wrote:
On Mon, Aug 26, 2013 at 04:27:59PM +0200, Andre Oppermann wrote: ...1. lle lock to rmlock. 2. if_addr and IN_ADDR locks to rmlocks. 3. routing table locking (rmlocks, and by doing away with rtentry locks and refcounting through copy-out on lookup and prohibition of having any pointers into the rtable).re. the last item, the problem is that we need to access *ifp after the route lookup, and this cannot be solved with a copy-on-lookup (I guess at the moment the rte has a refcounted pointer to the ifp).
The ifp has always been a bit lazy and later access is fine. We have the same problem with packets coming up from an interface (m->pkthdr.rcvif).
This is why i argued that it might be useful to cache into the socket a refcounted pointer into the ifp (or rte) and update it lazily (periodically or through generation counters).
Unless you want to ref-count every invocation of ifp the cheapest way to solve this is by making sure the ifp stays around for some time (2 minutes?) pointing to a dummy if_transmit after an interface departs. -- Andre _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
