> -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Pranay > Srivastava > Sent: Thursday, May 01, 2014 7:10 AM > To: [email protected] > Cc: kernelnewbies > Subject: Re: Regarding skb and skb_frags > > On Thu, May 1, 2014 at 7:29 PM, <[email protected]> wrote: > > On Thu, 01 May 2014 16:12:43 +0530, Pranay Srivastava said: > > > >> My question is that an Ethernet frame won't be bigger than 1500 bytes > >> [correct?] > > > > Incorrect. 10G and faster ethernet support jumbograms. We run our HPC 10G > > network with an MTU of 9000 (which is 2 pages and a bit more). > > > Ok. So in any case the driver won't poke past ethernet header to look > for the size [Correct?]. > So it means only when MTU is bigger than page size would there be a > possibility of skb_frags [Correct?].
I'm not sure what kernel version you are looking at, but when I do a search for skb_frags in the latest kernel sources at http://lxr.linux.no, I don't see any variables or structure members named skb_frags, though it shows up in comments in one driver. That being said, I believe skb fragments are also used to implement scatter/gather lists of packet payload data, even in packets less than or equal to the usual 1500 bytes. On the systems I work with, I've seen this happening in packets originating from the target system, i.e. egress path of local traffic. Jeff Haran _______________________________________________ Kernelnewbies mailing list [email protected] http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
