On Fri, Aug 04, 2006 at 02:02:51PM -0700, Jesse Brandeburg ([EMAIL PROTECTED]) wrote: > >> So how many skb allocation schemes do you code into a single driver? > >> Kmalloc everything, page alloc everything, combination of kmalloc and > >> page buffers for hardware that does header split? That's three > >> versions of the drivers receive processing and skb allocation that > >> need to be maintained. > > > >At least try to create scheme which will not end up in 32k allocation in > >atomic context. Generally I would recommend to use frag_list as much as > >possible (or you can reuse skb list). > > this is exactly what we ran into, you can't use skb list because the > ip fragmentation reassembly code overwrites it. If someone is feeling > particularly miffed by this i would love to see a patch that used > alloc_page() for all of our receive buffers for the legacy receive > path (e1000_clean_rx_irq) then we would be able to use nr_frags and > frag_list for receives. > > Oh, except that eth_type_trans can't handle the entire packet in the > frag_list (it wants the header in the skb->data)
Yes, part of the packet must live in skb->data, but it does not differ from frag_list management - place part of the data in skb->data and the rest into frag_list. If you can create several skbs and link them togeter you defenitely can organize pages into frag_list, just get pages from different skb->data and free those skbs. > anyway, this is not as easy a problem to solve as it would seem on the > surface. No one says it is easy or not, but I'me 100% sure that 32k allocation for 9k jumbo frame in atomic context is not what people expect from high-performance NIC. > Jesse > - > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to [EMAIL PROTECTED] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Evgeniy Polyakov - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
