> People on this list might not realize that there is a significant > overhead in supporting larger that 4K frames for XDP, that is larger > than one memory-page. So let me explain... > > It is actually trivially easy for XDP to support jumbo frames, if the > NIC hardware supports storing RX frames into higher order pages (aka > compound pages, more 4K pages physically after each-other) which most > HW does. (Page order0 = 4KB, order1=8KB, order2=16KB, order3=32KB). > As then XDP will work out-of-the-box, as the requirement is really that > packet-payload is layout as phys continuous memory. > For the use cases of XDP_DROP or XDP_PASS, could XDP send as much of the packet that fits in a single page up to the ebpf program and allow decisions based on that? For the flow bypass, ddos drop stuff, you only need the l3 header to make the PASS/DROP decision, not the entire packet. I suppose this would be a bit more complicated for modifying headers and using XDP_TX. -- - Justin
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