On Wed, Feb 6, 2013 at 3:36 PM, John Baldwin <[email protected]> wrote:
> On Wednesday, February 06, 2013 4:50:39 am Lino Sanfilippo wrote: > > > > Hi all, > > > > I want to implement a device driver for a NIC which stores received data > into chunks within > > a page (>=4k) in host memory. One page shall be used for multiple > packets and freed > > after all mbufs linked to that page have been processed. So I would like > to know what is the recommended way > > to handle this in FreeBSD? Any hints are very appreciated. > > I think you can get what you want by allocating M_JUMBOP mbuf clusters for > your receive buffers. When you want to split out a packet, allocate a new > packet header mbuf and use m_split() to let it take over the rest of the 4k > buffer and pass the original mbuf up to if_input() as the new packet. The > new mbufs you attach to the cluster via m_split() will all hold a reference > on the backing cluster and it won't be freed until all the mbufs are freed. > > The resulting mbufs will not be writeable (M_WRITABLE() will evaluate to 0), right? I don't know if this will be an issue in this particular application. > -- > John Baldwin > _______________________________________________ > [email protected] mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "[email protected]" > _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[email protected]"
