I support that! Med venlig hilsen / kind regards - Morten Br?rup
> -----Original Message----- > From: Olivier Matz [mailto:olivier.matz at 6wind.com] > Sent: Tuesday, October 25, 2016 3:14 PM > To: Morten Br?rup; dev at dpdk.org > Subject: Re: mbuf changes > > Hi, > > On 10/24/2016 05:49 PM, Morten Br?rup wrote: > > And here?s something new to think about: > > > > m->next already reveals if there are more segments to a packet. Which > > purpose does m->nb_segs serve that is not already covered by m->next? > > > > I was asking myself the same question some time ago: > http://dpdk.org/ml/archives/dev/2016-May/039483.html > > But it seems nb_segs is useful for PMDs on TX side, to anticipate how > many descriptors a packet will use in the TX ring. It can also help a > PMD to check that this packet is supported by the hardware (too many > segments) without browsing the list. > > So finally I think it should be kept in the mbuf. But as suggested by > Bruce, it could go in the second cache line, since m->next is also > there, at the condition that this field is set to 1 in mbuf_free(). > > Regards, > Olivier
