| Message ID | 1545856073-8680-3-git-send-email-u9012063@gmail.com |
|---|---|
| State | RFC, archived |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | AF_XDP support for veth. | expand |
Hi, William. Nice work. I have some feedback and questions. On 18/12/27 (木) 5:27:49, William Tu wrote: > The patch adds support for AF_XDP async xmit. Users can use > AF_XDP on both sides of the veth and get better performance, with > the cost of ksoftirqd doing the xmit. The veth_xsk_async_xmit > simply kicks the napi function, veth_poll, to receive the packets > that are on the umem transmit ring at the _peer_ side. > > Tested using two namespaces, one runs xdpsock and the other runs > xdp_rxq_info. A simple script comparing the performance with/without > AF_XDP shows improvement from 724Kpps to 1.1Mpps. > > ip netns add at_ns0 > ip link add p0 type veth peer name p1 > ip link set p0 netns at_ns0 > ip link set dev p1 up > ip netns exec at_ns0 ip link set dev p0 up > > # receiver > ip netns exec at_ns0 xdp_rxq_info --dev p0 --action XDP_DROP > > # sender > xdpsock -i p1 -t -N -z > or > xdpsock -i p1 -t -S > > Signed-off-by: William Tu <u9012063@gmail.com> > --- > drivers/net/veth.c | 200 ++++++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 199 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/veth.c b/drivers/net/veth.c > index f412ea1cef18..10cf9ded59f1 100644 > --- a/drivers/net/veth.c > +++ b/drivers/net/veth.c > @@ -25,6 +25,10 @@ > #include <linux/ptr_ring.h> > #include <linux/bpf_trace.h> > #include <linux/net_tstamp.h> > +#include <net/xdp_sock.h> > +#include <linux/mm.h> > +#include <linux/slab.h> > +#include <net/page_pool.h> > > #define DRV_NAME "veth" > #define DRV_VERSION "1.0" > @@ -53,6 +57,8 @@ struct veth_rq { > bool rx_notify_masked; > struct ptr_ring xdp_ring; > struct xdp_rxq_info xdp_rxq; > + struct xdp_umem *xsk_umem; > + u16 qid; veth_rq has 31 bytes hole after rx_notify_masked, so they should be placed there. > }; > > struct veth_priv { > @@ -737,11 +743,95 @@ static int veth_xdp_rcv(struct veth_rq *rq, int budget, unsigned int *xdp_xmit) > return done; > } > > +static int veth_xsk_poll(struct napi_struct *napi, int budget) > +{ > + struct veth_priv *priv, *peer_priv; > + struct net_device *dev, *peer_dev; > + struct veth_rq *peer_rq; > + struct veth_rq *rq = > + container_of(napi, struct veth_rq, xdp_napi); > + int done = 0; > + > + dev = rq->dev; > + priv = netdev_priv(dev); > + peer_dev = priv->peer; > + peer_priv = netdev_priv(peer_dev); > + peer_rq = &peer_priv->rq[rq->qid]; > + > + while (peer_rq->xsk_umem && budget--) { > + unsigned int inner_xdp_xmit = 0; > + unsigned int metasize = 0; > + struct xdp_frame *xdpf; > + bool dropped = false; > + struct sk_buff *skb; > + struct page *page; > + void *vaddr; > + void *addr; > + u32 len; > + > + if (!xsk_umem_consume_tx_virtual(peer_rq->xsk_umem, &vaddr, &len)) > + break; How do you prevent races around xsk_umem? It seems you are checking xsk_umem in above while() condition, but there is no guarantee that xsk_umem is not NULL here, since umem can be disabled under us? > + > + page = dev_alloc_page(); > + if (!page) { > + xsk_umem_complete_tx(peer_rq->xsk_umem, 1); > + xsk_umem_consume_tx_done(peer_rq->xsk_umem); > + return -ENOMEM; > + } > + > + addr = page_to_virt(page); > + xdpf = addr; > + memset(xdpf, 0, sizeof(*xdpf)); > + > + addr += sizeof(*xdpf); > + memcpy(addr, vaddr, len); > + > + xdpf->data = addr + metasize; > + xdpf->len = len; > + xdpf->headroom = 0; > + xdpf->metasize = metasize; > + xdpf->mem.type = MEM_TYPE_PAGE_SHARED; > + > + /* put into rq */ > + skb = veth_xdp_rcv_one(rq, xdpf, &inner_xdp_xmit); > + if (!skb) { > + /* Peer side has XDP program attached */ > + if (inner_xdp_xmit & VETH_XDP_TX) { > + /* Not supported */ > + pr_warn("veth: peer XDP_TX not supported\n"); As this can be triggered by users we need ratelimit at least. But since this is envisioned to be used in OVS, XDP_TX would be a very important feature to me. I expect XDP programs in containers to process packets and send back to OVS. > + xdp_return_frame(xdpf); > + dropped = true; > + goto skip_tx; > + } else if (inner_xdp_xmit & VETH_XDP_REDIR) { > + xdp_do_flush_map(); > + } else { > + dropped = true; > + } > + } else { > + napi_gro_receive(&rq->xdp_napi, skb); > + } > +skip_tx: > + xsk_umem_complete_tx(peer_rq->xsk_umem, 1); > + xsk_umem_consume_tx_done(peer_rq->xsk_umem); > + > + /* update rq stats */ > + u64_stats_update_begin(&rq->stats.syncp); > + rq->stats.xdp_packets++; > + rq->stats.xdp_bytes += len; > + if (dropped) > + rq->stats.xdp_drops++; > + u64_stats_update_end(&rq->stats.syncp); > + done++; > + } > + return done; > +} > + > static int veth_poll(struct napi_struct *napi, int budget) > { > struct veth_rq *rq = > container_of(napi, struct veth_rq, xdp_napi); > unsigned int xdp_xmit = 0; > + int tx_done; > int done; > > xdp_set_return_frame_no_direct(); > @@ -756,13 +846,17 @@ static int veth_poll(struct napi_struct *napi, int budget) > } > } > > + tx_done = veth_xsk_poll(napi, budget); > + if (tx_done > 0) > + done += tx_done; > + This receives packets more than budget. > if (xdp_xmit & VETH_XDP_TX) > veth_xdp_flush(rq->dev); > if (xdp_xmit & VETH_XDP_REDIR) > xdp_do_flush_map(); > xdp_clear_return_frame_no_direct(); > > - return done; > + return done > budget ? budget : done; > } > > static int veth_napi_add(struct net_device *dev) > @@ -776,6 +870,7 @@ static int veth_napi_add(struct net_device *dev) > err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL); > if (err) > goto err_xdp_ring; > + rq->qid = i; > } > > for (i = 0; i < dev->real_num_rx_queues; i++) { > @@ -812,6 +907,7 @@ static void veth_napi_del(struct net_device *dev) > netif_napi_del(&rq->xdp_napi); > rq->rx_notify_masked = false; > ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free); > + rq->qid = -1; > } > } > > @@ -836,6 +932,7 @@ static int veth_enable_xdp(struct net_device *dev) > > /* Save original mem info as it can be overwritten */ > rq->xdp_mem = rq->xdp_rxq.mem; > + rq->qid = i; > } > > err = veth_napi_add(dev); > @@ -1115,6 +1212,84 @@ static u32 veth_xdp_query(struct net_device *dev) > return 0; > } > > +int veth_xsk_umem_query(struct net_device *dev, struct xdp_umem **umem, > + u16 qid) > +{ > + struct xdp_umem *queried_umem; > + > + queried_umem = xdp_get_umem_from_qid(dev, qid); > + > + if (!queried_umem) > + return -EINVAL; > + > + *umem = queried_umem; > + return 0; > +} > + > +static int veth_xsk_umem_enable(struct net_device *dev, > + struct xdp_umem *umem, > + u16 qid) > +{ > + struct veth_priv *priv = netdev_priv(dev); > + struct xdp_umem_fq_reuse *reuseq; > + int err = 0; > + > + if (qid >= dev->real_num_rx_queues) > + return -EINVAL; > + > + reuseq = xsk_reuseq_prepare(priv->rq[0].xdp_ring.size); > + if (!reuseq) > + return -ENOMEM; > + > + xsk_reuseq_free(xsk_reuseq_swap(umem, reuseq)); > + > + priv->rq[qid].xsk_umem = umem; > + > + return err; > +} > + > +static int veth_xsk_umem_disable(struct net_device *dev, > + u16 qid) > +{ > + struct veth_priv *priv = netdev_priv(dev); > + struct xdp_umem *umem; > + > + umem = xdp_get_umem_from_qid(dev, qid); > + if (!umem) > + return -EINVAL; > + > + priv->rq[qid].xsk_umem = NULL; > + return 0; > +} > + > +int veth_xsk_umem_setup(struct net_device *dev, struct xdp_umem *umem, > + u16 qid) > +{ > + return umem ? veth_xsk_umem_enable(dev, umem, qid) : > + veth_xsk_umem_disable(dev, qid); > +} > + > +int veth_xsk_async_xmit(struct net_device *dev, u32 qid) > +{ > + struct veth_priv *priv, *peer_priv; > + struct net_device *peer_dev; > + struct veth_rq *peer_rq; > + > + priv = netdev_priv(dev); > + peer_dev = priv->peer; > + peer_priv = netdev_priv(peer_dev); > + peer_rq = &peer_priv->rq[qid]; > + > + if (qid >= dev->real_num_rx_queues) > + return -ENXIO; > + > + /* Schedule the peer side NAPI to receive */ > + if (!napi_if_scheduled_mark_missed(&peer_rq->xdp_napi)) > + napi_schedule(&peer_rq->xdp_napi); > + > + return 0; > +} > + > static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp) > { > switch (xdp->command) { > @@ -1123,6 +1298,28 @@ static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp) > case XDP_QUERY_PROG: > xdp->prog_id = veth_xdp_query(dev); > return 0; > + case XDP_QUERY_XSK_UMEM: > + return veth_xsk_umem_query(dev, &xdp->xsk.umem, > + xdp->xsk.queue_id); > + case XDP_SETUP_XSK_UMEM: { > + struct veth_priv *priv; > + int err; > + > + /* Enable NAPI on both sides, by enabling > + * their XDP. > + */ > + err = veth_enable_xdp(dev); Looks like there is no need to enable XDP on this side. You only use peer's NAPI, right? > + if (err) > + return err; > + > + priv = netdev_priv(dev); > + err = veth_enable_xdp(priv->peer); Enabling NAPI here and never disable it? Also, what happens if peer disables XDP later by detaching an XDP program? Probably you need something like refcounting. BTW I'm not 100% sure if current way of accessing peer rq in NAPI handler is safe although I did not find an obvious problem. Looking into physical NIC drivers, ndo_async_xmit() is expected to kick TX softirq? This should be something like below process in veth. Say you attach an xsk to veth A, and B is the peer of A. 1. async_xmit kicks A's NAPI 2. A's NAPI drains xsk tx_ring and pushes frames into B's xdp_ring, then kicks B's NAPI 3. B's NAPI drains xdp_ring and process xdp_frames in the same way as normal xdp_frames. What you are currently doing seems to be skipping 2 and making B's NAPI directly drain tx_ring of xsk bound to A. I don't have particular opinion about which is better. Probably your approach is more efficient performance-wise? If later you find some race with your approach, please consider more physical-NIC-like approach I described above. > + if (err) > + return err; > + > + return veth_xsk_umem_setup(dev, xdp->xsk.umem, > + xdp->xsk.queue_id); > + } > default: > return -EINVAL; > } > @@ -1145,6 +1342,7 @@ static const struct net_device_ops veth_netdev_ops = { > .ndo_set_rx_headroom = veth_set_rx_headroom, > .ndo_bpf = veth_xdp, > .ndo_xdp_xmit = veth_xdp_xmit, > + .ndo_xsk_async_xmit = veth_xsk_async_xmit, > }; > > #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \ >
Hi Toshiaki, Thanks a lot for the feedback. On Tue, Jan 1, 2019 at 5:44 AM Toshiaki Makita <toshiaki.makita1@gmail.com> wrote: > > Hi, William. Nice work. > I have some feedback and questions. > > > + while (peer_rq->xsk_umem && budget--) { > > + unsigned int inner_xdp_xmit = 0; > > + unsigned int metasize = 0; > > + struct xdp_frame *xdpf; > > + bool dropped = false; > > + struct sk_buff *skb; > > + struct page *page; > > + void *vaddr; > > + void *addr; > > + u32 len; > > + > > + if (!xsk_umem_consume_tx_virtual(peer_rq->xsk_umem, &vaddr, &len)) > > + break; > > How do you prevent races around xsk_umem? > It seems you are checking xsk_umem in above while() condition, but there > is no guarantee that xsk_umem is not NULL here, since umem can be > disabled under us? you're right. Looking at similar code (i40e_xsk_umem_enable/disable). When setting xsk_umem to NULL (at veth_xsk_umem_disable), I should first disable the napi, then set to NULL. > > > + > > + page = dev_alloc_page(); > > + if (!page) { > > + xsk_umem_complete_tx(peer_rq->xsk_umem, 1); > > + xsk_umem_consume_tx_done(peer_rq->xsk_umem); > > + return -ENOMEM; > > + } > > + > > + addr = page_to_virt(page); > > + xdpf = addr; > > + memset(xdpf, 0, sizeof(*xdpf)); > > + > > + addr += sizeof(*xdpf); > > + memcpy(addr, vaddr, len); > > + > > + xdpf->data = addr + metasize; > > + xdpf->len = len; > > + xdpf->headroom = 0; > > + xdpf->metasize = metasize; > > + xdpf->mem.type = MEM_TYPE_PAGE_SHARED; > > + > > + /* put into rq */ > > + skb = veth_xdp_rcv_one(rq, xdpf, &inner_xdp_xmit); > > + if (!skb) { > > + /* Peer side has XDP program attached */ > > + if (inner_xdp_xmit & VETH_XDP_TX) { > > + /* Not supported */ > > + pr_warn("veth: peer XDP_TX not supported\n"); > > As this can be triggered by users we need ratelimit at least. How to rate limit here? Can I slow down the napi poll or reduce the budget? > > But since this is envisioned to be used in OVS, XDP_TX would be a very > important feature to me. I expect XDP programs in containers to process > packets and send back to OVS. It's a little tricky here since the receiving veth pulls the packet sent from its peer side, but due to XDP_TX, it has to put the packet back to its peer side to receive. But I can see the use case you mentioned. Let me think about how to implement. > > > + xdp_return_frame(xdpf); > > + dropped = true; > > + goto skip_tx; > > + } else if (inner_xdp_xmit & VETH_XDP_REDIR) { > > + xdp_do_flush_map(); > > + } else { > > + dropped = true; > > + } > > + } else { > > + napi_gro_receive(&rq->xdp_napi, skb); > > + } > > +skip_tx: > > + xsk_umem_complete_tx(peer_rq->xsk_umem, 1); > > + xsk_umem_consume_tx_done(peer_rq->xsk_umem); > > + > > + /* update rq stats */ > > + u64_stats_update_begin(&rq->stats.syncp); > > + rq->stats.xdp_packets++; > > + rq->stats.xdp_bytes += len; > > + if (dropped) > > + rq->stats.xdp_drops++; > > + u64_stats_update_end(&rq->stats.syncp); > > + done++; > > + } > > + return done; > > +} > > + > > static int veth_poll(struct napi_struct *napi, int budget) > > { > > struct veth_rq *rq = > > container_of(napi, struct veth_rq, xdp_napi); > > unsigned int xdp_xmit = 0; > > + int tx_done; > > int done; > > > > xdp_set_return_frame_no_direct(); > > @@ -756,13 +846,17 @@ static int veth_poll(struct napi_struct *napi, int budget) > > } > > } > > > > + tx_done = veth_xsk_poll(napi, budget); > > + if (tx_done > 0) > > + done += tx_done; > > + > > This receives packets more than budget. > > > if (xdp_xmit & VETH_XDP_TX) > > veth_xdp_flush(rq->dev); > > if (xdp_xmit & VETH_XDP_REDIR) > > xdp_do_flush_map(); > > xdp_clear_return_frame_no_direct(); > > > > - return done; > > + return done > budget ? budget : done; > > } > > > > static int veth_napi_add(struct net_device *dev) > > @@ -776,6 +870,7 @@ static int veth_napi_add(struct net_device *dev) > > err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL); > > if (err) > > goto err_xdp_ring; > > + rq->qid = i; > > } > > > > for (i = 0; i < dev->real_num_rx_queues; i++) { > > @@ -812,6 +907,7 @@ static void veth_napi_del(struct net_device *dev) > > netif_napi_del(&rq->xdp_napi); > > rq->rx_notify_masked = false; > > ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free); > > + rq->qid = -1; > > } > > } > > > > @@ -836,6 +932,7 @@ static int veth_enable_xdp(struct net_device *dev) > > > > /* Save original mem info as it can be overwritten */ > > rq->xdp_mem = rq->xdp_rxq.mem; > > + rq->qid = i; > > } > > > > err = veth_napi_add(dev); > > @@ -1115,6 +1212,84 @@ static u32 veth_xdp_query(struct net_device *dev) > > return 0; > > } > > > > +int veth_xsk_umem_query(struct net_device *dev, struct xdp_umem **umem, > > + u16 qid) > > +{ > > + struct xdp_umem *queried_umem; > > + > > + queried_umem = xdp_get_umem_from_qid(dev, qid); > > + > > + if (!queried_umem) > > + return -EINVAL; > > + > > + *umem = queried_umem; > > + return 0; > > +} > > + > > +static int veth_xsk_umem_enable(struct net_device *dev, > > + struct xdp_umem *umem, > > + u16 qid) > > +{ > > + struct veth_priv *priv = netdev_priv(dev); > > + struct xdp_umem_fq_reuse *reuseq; > > + int err = 0; > > + > > + if (qid >= dev->real_num_rx_queues) > > + return -EINVAL; > > + > > + reuseq = xsk_reuseq_prepare(priv->rq[0].xdp_ring.size); > > + if (!reuseq) > > + return -ENOMEM; > > + > > + xsk_reuseq_free(xsk_reuseq_swap(umem, reuseq)); > > + > > + priv->rq[qid].xsk_umem = umem; > > + > > + return err; > > +} > > + > > +static int veth_xsk_umem_disable(struct net_device *dev, > > + u16 qid) > > +{ > > + struct veth_priv *priv = netdev_priv(dev); > > + struct xdp_umem *umem; > > + > > + umem = xdp_get_umem_from_qid(dev, qid); > > + if (!umem) > > + return -EINVAL; > > + > > + priv->rq[qid].xsk_umem = NULL; > > + return 0; > > +} > > + > > +int veth_xsk_umem_setup(struct net_device *dev, struct xdp_umem *umem, > > + u16 qid) > > +{ > > + return umem ? veth_xsk_umem_enable(dev, umem, qid) : > > + veth_xsk_umem_disable(dev, qid); > > +} > > + > > +int veth_xsk_async_xmit(struct net_device *dev, u32 qid) > > +{ > > + struct veth_priv *priv, *peer_priv; > > + struct net_device *peer_dev; > > + struct veth_rq *peer_rq; > > + > > + priv = netdev_priv(dev); > > + peer_dev = priv->peer; > > + peer_priv = netdev_priv(peer_dev); > > + peer_rq = &peer_priv->rq[qid]; > > + > > + if (qid >= dev->real_num_rx_queues) > > + return -ENXIO; > > + > > + /* Schedule the peer side NAPI to receive */ > > + if (!napi_if_scheduled_mark_missed(&peer_rq->xdp_napi)) > > + napi_schedule(&peer_rq->xdp_napi); > > + > > + return 0; > > +} > > + > > static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp) > > { > > switch (xdp->command) { > > @@ -1123,6 +1298,28 @@ static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp) > > case XDP_QUERY_PROG: > > xdp->prog_id = veth_xdp_query(dev); > > return 0; > > + case XDP_QUERY_XSK_UMEM: > > + return veth_xsk_umem_query(dev, &xdp->xsk.umem, > > + xdp->xsk.queue_id); > > + case XDP_SETUP_XSK_UMEM: { > > + struct veth_priv *priv; > > + int err; > > + > > + /* Enable NAPI on both sides, by enabling > > + * their XDP. > > + */ > > + err = veth_enable_xdp(dev); > > Looks like there is no need to enable XDP on this side. You only use > peer's NAPI, right? Yes, thanks. The peer's NAPI is doing the work. > > > + if (err) > > + return err; > > + > > + priv = netdev_priv(dev); > > + err = veth_enable_xdp(priv->peer); > > Enabling NAPI here and never disable it? Here XDP_SETUP_XSK_UMEM might be enable or disable, so I should disable NAPI when receiving umem disable command. Will fix it in next version. > Also, what happens if peer disables XDP later by detaching an XDP program? > Probably you need something like refcounting. OK, so the refconting will keep the NAPI running when XDP program is detached. > > > BTW I'm not 100% sure if current way of accessing peer rq in NAPI > handler is safe although I did not find an obvious problem. > > Looking into physical NIC drivers, ndo_async_xmit() is expected to kick > TX softirq? This should be something like below process in veth. right, the physical NIC driver (i40e and ixgbe), the async_xmit simply kick TX softirq. For veth, we're doing a little different. We kick the peer side's RX softirq. > > Say you attach an xsk to veth A, and B is the peer of A. > > 1. async_xmit kicks A's NAPI > 2. A's NAPI drains xsk tx_ring and pushes frames into B's xdp_ring, then > kicks B's NAPI > 3. B's NAPI drains xdp_ring and process xdp_frames in the same way as > normal xdp_frames. > > What you are currently doing seems to be skipping 2 and making B's NAPI > directly drain tx_ring of xsk bound to A. Right. > > I don't have particular opinion about which is better. Probably your > approach is more efficient performance-wise? If later you find some race > with your approach, please consider more physical-NIC-like approach I > described above. Yes, I thought without pushing/draining frames into/outof xdp_ring might have better performance. I will work on the next version. Thanks! William > > > + if (err) > > + return err; > > + > > + return veth_xsk_umem_setup(dev, xdp->xsk.umem, > > + xdp->xsk.queue_id); > > + } > > default: > > return -EINVAL; > > } > > @@ -1145,6 +1342,7 @@ static const struct net_device_ops veth_netdev_ops = { > > .ndo_set_rx_headroom = veth_set_rx_headroom, > > .ndo_bpf = veth_xdp, > > .ndo_xdp_xmit = veth_xdp_xmit, > > + .ndo_xsk_async_xmit = veth_xsk_async_xmit, > > }; > > > > #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \ > >
On 2019/01/06 0:55, William Tu wrote: ... >>> + /* put into rq */ >>> + skb = veth_xdp_rcv_one(rq, xdpf, &inner_xdp_xmit); >>> + if (!skb) { >>> + /* Peer side has XDP program attached */ >>> + if (inner_xdp_xmit & VETH_XDP_TX) { >>> + /* Not supported */ >>> + pr_warn("veth: peer XDP_TX not supported\n"); >> >> As this can be triggered by users we need ratelimit at least. > How to rate limit here? Can I slow down the napi poll or reduce the budget? net_ratelimit() >> But since this is envisioned to be used in OVS, XDP_TX would be a very >> important feature to me. I expect XDP programs in containers to process >> packets and send back to OVS. > > It's a little tricky here since the receiving veth pulls the packet sent from > its peer side, but due to XDP_TX, it has to put the packet back to its peer > side to receive. But I can see the use case you mentioned. Let me think > about how to implement. You have already implemented XDP_REDIRECT. XDP_TX is kind of special case of XDP_REDIRECT, so I wonder why you think XDP_TX is especially difficult.
diff --git a/drivers/net/veth.c b/drivers/net/veth.c index f412ea1cef18..10cf9ded59f1 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -25,6 +25,10 @@ #include <linux/ptr_ring.h> #include <linux/bpf_trace.h> #include <linux/net_tstamp.h> +#include <net/xdp_sock.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <net/page_pool.h> #define DRV_NAME "veth" #define DRV_VERSION "1.0" @@ -53,6 +57,8 @@ struct veth_rq { bool rx_notify_masked; struct ptr_ring xdp_ring; struct xdp_rxq_info xdp_rxq; + struct xdp_umem *xsk_umem; + u16 qid; }; struct veth_priv { @@ -737,11 +743,95 @@ static int veth_xdp_rcv(struct veth_rq *rq, int budget, unsigned int *xdp_xmit) return done; } +static int veth_xsk_poll(struct napi_struct *napi, int budget) +{ + struct veth_priv *priv, *peer_priv; + struct net_device *dev, *peer_dev; + struct veth_rq *peer_rq; + struct veth_rq *rq = + container_of(napi, struct veth_rq, xdp_napi); + int done = 0; + + dev = rq->dev; + priv = netdev_priv(dev); + peer_dev = priv->peer; + peer_priv = netdev_priv(peer_dev); + peer_rq = &peer_priv->rq[rq->qid]; + + while (peer_rq->xsk_umem && budget--) { + unsigned int inner_xdp_xmit = 0; + unsigned int metasize = 0; + struct xdp_frame *xdpf; + bool dropped = false; + struct sk_buff *skb; + struct page *page; + void *vaddr; + void *addr; + u32 len; + + if (!xsk_umem_consume_tx_virtual(peer_rq->xsk_umem, &vaddr, &len)) + break; + + page = dev_alloc_page(); + if (!page) { + xsk_umem_complete_tx(peer_rq->xsk_umem, 1); + xsk_umem_consume_tx_done(peer_rq->xsk_umem); + return -ENOMEM; + } + + addr = page_to_virt(page); + xdpf = addr; + memset(xdpf, 0, sizeof(*xdpf)); + + addr += sizeof(*xdpf); + memcpy(addr, vaddr, len); + + xdpf->data = addr + metasize; + xdpf->len = len; + xdpf->headroom = 0; + xdpf->metasize = metasize; + xdpf->mem.type = MEM_TYPE_PAGE_SHARED; + + /* put into rq */ + skb = veth_xdp_rcv_one(rq, xdpf, &inner_xdp_xmit); + if (!skb) { + /* Peer side has XDP program attached */ + if (inner_xdp_xmit & VETH_XDP_TX) { + /* Not supported */ + pr_warn("veth: peer XDP_TX not supported\n"); + xdp_return_frame(xdpf); + dropped = true; + goto skip_tx; + } else if (inner_xdp_xmit & VETH_XDP_REDIR) { + xdp_do_flush_map(); + } else { + dropped = true; + } + } else { + napi_gro_receive(&rq->xdp_napi, skb); + } +skip_tx: + xsk_umem_complete_tx(peer_rq->xsk_umem, 1); + xsk_umem_consume_tx_done(peer_rq->xsk_umem); + + /* update rq stats */ + u64_stats_update_begin(&rq->stats.syncp); + rq->stats.xdp_packets++; + rq->stats.xdp_bytes += len; + if (dropped) + rq->stats.xdp_drops++; + u64_stats_update_end(&rq->stats.syncp); + done++; + } + return done; +} + static int veth_poll(struct napi_struct *napi, int budget) { struct veth_rq *rq = container_of(napi, struct veth_rq, xdp_napi); unsigned int xdp_xmit = 0; + int tx_done; int done; xdp_set_return_frame_no_direct(); @@ -756,13 +846,17 @@ static int veth_poll(struct napi_struct *napi, int budget) } } + tx_done = veth_xsk_poll(napi, budget); + if (tx_done > 0) + done += tx_done; + if (xdp_xmit & VETH_XDP_TX) veth_xdp_flush(rq->dev); if (xdp_xmit & VETH_XDP_REDIR) xdp_do_flush_map(); xdp_clear_return_frame_no_direct(); - return done; + return done > budget ? budget : done; } static int veth_napi_add(struct net_device *dev) @@ -776,6 +870,7 @@ static int veth_napi_add(struct net_device *dev) err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL); if (err) goto err_xdp_ring; + rq->qid = i; } for (i = 0; i < dev->real_num_rx_queues; i++) { @@ -812,6 +907,7 @@ static void veth_napi_del(struct net_device *dev) netif_napi_del(&rq->xdp_napi); rq->rx_notify_masked = false; ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free); + rq->qid = -1; } } @@ -836,6 +932,7 @@ static int veth_enable_xdp(struct net_device *dev) /* Save original mem info as it can be overwritten */ rq->xdp_mem = rq->xdp_rxq.mem; + rq->qid = i; } err = veth_napi_add(dev); @@ -1115,6 +1212,84 @@ static u32 veth_xdp_query(struct net_device *dev) return 0; } +int veth_xsk_umem_query(struct net_device *dev, struct xdp_umem **umem, + u16 qid) +{ + struct xdp_umem *queried_umem; + + queried_umem = xdp_get_umem_from_qid(dev, qid); + + if (!queried_umem) + return -EINVAL; + + *umem = queried_umem; + return 0; +} + +static int veth_xsk_umem_enable(struct net_device *dev, + struct xdp_umem *umem, + u16 qid) +{ + struct veth_priv *priv = netdev_priv(dev); + struct xdp_umem_fq_reuse *reuseq; + int err = 0; + + if (qid >= dev->real_num_rx_queues) + return -EINVAL; + + reuseq = xsk_reuseq_prepare(priv->rq[0].xdp_ring.size); + if (!reuseq) + return -ENOMEM; + + xsk_reuseq_free(xsk_reuseq_swap(umem, reuseq)); + + priv->rq[qid].xsk_umem = umem; + + return err; +} + +static int veth_xsk_umem_disable(struct net_device *dev, + u16 qid) +{ + struct veth_priv *priv = netdev_priv(dev); + struct xdp_umem *umem; + + umem = xdp_get_umem_from_qid(dev, qid); + if (!umem) + return -EINVAL; + + priv->rq[qid].xsk_umem = NULL; + return 0; +} + +int veth_xsk_umem_setup(struct net_device *dev, struct xdp_umem *umem, + u16 qid) +{ + return umem ? veth_xsk_umem_enable(dev, umem, qid) : + veth_xsk_umem_disable(dev, qid); +} + +int veth_xsk_async_xmit(struct net_device *dev, u32 qid) +{ + struct veth_priv *priv, *peer_priv; + struct net_device *peer_dev; + struct veth_rq *peer_rq; + + priv = netdev_priv(dev); + peer_dev = priv->peer; + peer_priv = netdev_priv(peer_dev); + peer_rq = &peer_priv->rq[qid]; + + if (qid >= dev->real_num_rx_queues) + return -ENXIO; + + /* Schedule the peer side NAPI to receive */ + if (!napi_if_scheduled_mark_missed(&peer_rq->xdp_napi)) + napi_schedule(&peer_rq->xdp_napi); + + return 0; +} + static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp) { switch (xdp->command) { @@ -1123,6 +1298,28 @@ static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp) case XDP_QUERY_PROG: xdp->prog_id = veth_xdp_query(dev); return 0; + case XDP_QUERY_XSK_UMEM: + return veth_xsk_umem_query(dev, &xdp->xsk.umem, + xdp->xsk.queue_id); + case XDP_SETUP_XSK_UMEM: { + struct veth_priv *priv; + int err; + + /* Enable NAPI on both sides, by enabling + * their XDP. + */ + err = veth_enable_xdp(dev); + if (err) + return err; + + priv = netdev_priv(dev); + err = veth_enable_xdp(priv->peer); + if (err) + return err; + + return veth_xsk_umem_setup(dev, xdp->xsk.umem, + xdp->xsk.queue_id); + } default: return -EINVAL; } @@ -1145,6 +1342,7 @@ static const struct net_device_ops veth_netdev_ops = { .ndo_set_rx_headroom = veth_set_rx_headroom, .ndo_bpf = veth_xdp, .ndo_xdp_xmit = veth_xdp_xmit, + .ndo_xsk_async_xmit = veth_xsk_async_xmit, }; #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \
The patch adds support for AF_XDP async xmit. Users can use AF_XDP on both sides of the veth and get better performance, with the cost of ksoftirqd doing the xmit. The veth_xsk_async_xmit simply kicks the napi function, veth_poll, to receive the packets that are on the umem transmit ring at the _peer_ side. Tested using two namespaces, one runs xdpsock and the other runs xdp_rxq_info. A simple script comparing the performance with/without AF_XDP shows improvement from 724Kpps to 1.1Mpps. ip netns add at_ns0 ip link add p0 type veth peer name p1 ip link set p0 netns at_ns0 ip link set dev p1 up ip netns exec at_ns0 ip link set dev p0 up # receiver ip netns exec at_ns0 xdp_rxq_info --dev p0 --action XDP_DROP # sender xdpsock -i p1 -t -N -z or xdpsock -i p1 -t -S Signed-off-by: William Tu <u9012063@gmail.com> --- drivers/net/veth.c | 200 ++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 199 insertions(+), 1 deletion(-)