On 16-11-21 03:13 PM, Michael S. Tsirkin wrote: > On Sat, Nov 19, 2016 at 06:51:04PM -0800, John Fastabend wrote: >> XDP requires using isolated transmit queues to avoid interference >> with normal networking stack (BQL, NETDEV_TX_BUSY, etc). This patch >> adds a XDP queue per cpu when a XDP program is loaded and does not >> expose the queues to the OS via the normal API call to >> netif_set_real_num_tx_queues(). This way the stack will never push >> an skb to these queues. >> >> However virtio/vhost/qemu implementation only allows for creating >> TX/RX queue pairs at this time so creating only TX queues was not >> possible. And because the associated RX queues are being created I >> went ahead and exposed these to the stack and let the backend use >> them. This creates more RX queues visible to the network stack than >> TX queues which is worth mentioning but does not cause any issues as >> far as I can tell. >> >> Signed-off-by: John Fastabend <john.r.fastab...@intel.com> > > FYI what's supposed to happen is packets from the same > flow going in the reverse direction will go on the > same queue. > > This might come in handy when implementing RX XDP. >
Yeah but if its the first packet not part of a flow then presumably it can pick any queue but its worth keeping in mind certainly. .John
