The patch adds support for AF_XDP async xmit. Users can use
AF_XDP on both side 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 run, and the transmit
logic is implemented there.
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 <u9012...@gmail.com>
---
drivers/net/veth.c | 247 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 245 insertions(+), 2 deletions(-)
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index f412ea1cef18..5171ddad5973 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 +57,7 @@ struct veth_rq {
bool rx_notify_masked;
struct ptr_ring xdp_ring;
struct xdp_rxq_info xdp_rxq;
+ struct xdp_umem *xsk_umem;
};
struct veth_priv {
@@ -61,6 +66,11 @@ struct veth_priv {
struct bpf_prog *_xdp_prog;
struct veth_rq *rq;
unsigned int requested_headroom;
+
+ /* AF_XDP zero-copy */
+ struct xdp_umem **xsk_umems;
+ u16 num_xsk_umems_used;
+ u16 num_xsk_umems;
};
/*
@@ -742,10 +752,87 @@ 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 done;
+ int tx_budget = budget;
+ int done = 0;
+
+ /* tx: use netif_tx_napi_add or here? */
+ while (rq->xsk_umem && tx_budget--) {
+ struct veth_priv *priv, *peer_priv;
+ struct net_device *dev, *peer_dev;
+ unsigned int inner_xdp_xmit = 0;
+ unsigned int metasize = 0;
+ struct veth_rq *peer_rq;
+ struct xdp_frame *xdpf;
+ bool dropped = false;
+ struct sk_buff *skb;
+ struct page *page;
+ char *vaddr;
+ void *addr;
+ u32 len;
+
+ if (!xsk_umem_consume_tx_virtual(rq->xsk_umem, &vaddr, &len))
+ break;
+
+ page = dev_alloc_page();
+ if (!page)
+ 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;
+
+ /* Invoke peer rq to rcv */
+ dev = rq->dev;
+ priv = netdev_priv(dev);
+ peer_dev = priv->peer;
+ peer_priv = netdev_priv(peer_dev);
+ peer_rq = peer_priv->rq;
+
+ /* put into peer rq */
+ skb = veth_xdp_rcv_one(peer_rq, xdpf, &inner_xdp_xmit);
+ if (!skb) {
+ /* Peer side has XDP program attached */
+ if (inner_xdp_xmit & VETH_XDP_TX) {
+ /* Not supported */
+ xsk_umem_complete_tx(rq->xsk_umem, 1);
+ xsk_umem_consume_tx_done(rq->xsk_umem);
+ xdp_return_frame(xdpf);
+ goto skip_tx;
+ } else if (inner_xdp_xmit & VETH_XDP_REDIR) {
+ xdp_do_flush_map();
+ } else {
+ dropped = true;
+ }
+ } else {
+ /* Peer side has no XDP attached */
+ napi_gro_receive(&peer_rq->xdp_napi, skb);
+ }
+ xsk_umem_complete_tx(rq->xsk_umem, 1);
+ xsk_umem_consume_tx_done(rq->xsk_umem);
+
+ /* update peer stats */
+ u64_stats_update_begin(&peer_rq->stats.syncp);
+ peer_rq->stats.xdp_packets++;
+ peer_rq->stats.xdp_bytes += len;
+ if (dropped)
+ rq->stats.xdp_drops++;
+ u64_stats_update_end(&peer_rq->stats.syncp);
+ done++;
+ }
+skip_tx:
+ /* rx */
xdp_set_return_frame_no_direct();
- done = veth_xdp_rcv(rq, budget, &xdp_xmit);
+ done += veth_xdp_rcv(rq, budget, &xdp_xmit);
if (done < budget && napi_complete_done(napi, done)) {
/* Write rx_notify_masked before reading ptr_ring */
@@ -1115,6 +1202,141 @@ static u32 veth_xdp_query(struct net_device *dev)
return 0;
}
+static int veth_alloc_xsk_umems(struct net_device *dev)
+{
+ struct veth_priv *priv = netdev_priv(dev);
+
+ if (priv->xsk_umems)
+ return 0;
+
+ priv->num_xsk_umems_used = 0;
+ priv->num_xsk_umems = dev->real_num_rx_queues;
+ priv->xsk_umems = kcalloc(priv->num_xsk_umems,
+ sizeof(*priv->xsk_umems),
+ GFP_KERNEL);
+ return 0;
+}
+
+static int veth_add_xsk_umem(struct net_device *dev,
+ struct xdp_umem *umem,
+ u16 qid)
+{
+ struct veth_priv *priv = netdev_priv(dev);
+ int err;
+
+ err = veth_alloc_xsk_umems(dev);
+ if (err)
+ return err;
+
+ priv->xsk_umems[qid] = umem;
+ priv->num_xsk_umems_used++;
+ priv->rq[qid].xsk_umem = umem;
+
+ return 0;
+}
+
+static void veth_remove_xsk_umem(struct net_device *dev, u16 qid)
+{
+ struct veth_priv *priv = netdev_priv(dev);
+
+ priv->xsk_umems[qid] = NULL;
+ priv->num_xsk_umems_used--;
+
+ if (priv->num_xsk_umems == 0) {
+ kfree(priv->xsk_umems);
+ priv->xsk_umems = NULL;
+ priv->num_xsk_umems = 0;
+ }
+}
+
+int veth_xsk_umem_query(struct net_device *dev, struct xdp_umem **umem,
+ u16 qid)
+{
+ struct veth_priv *priv = netdev_priv(dev);
+
+ if (qid >= dev->real_num_rx_queues)
+ return -EINVAL;
+
+ if (priv->xsk_umems) {
+ if (qid >= priv->num_xsk_umems)
+ return -EINVAL;
+ *umem = priv->xsk_umems[qid];
+ return 0;
+ }
+
+ *umem = NULL;
+ 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;
+
+ if (priv->xsk_umems) {
+ if (qid >= priv->num_xsk_umems)
+ return -EINVAL;
+ if (priv->xsk_umems[qid])
+ return -EBUSY;
+ }
+
+ reuseq = xsk_reuseq_prepare(priv->rq[0].xdp_ring.size);
+ if (!reuseq)
+ return -ENOMEM;
+
+ xsk_reuseq_free(xsk_reuseq_swap(umem, reuseq));
+
+ /* Check if_running and disable/enable? */
+ err = veth_add_xsk_umem(dev, umem, qid);
+
+ return err;
+}
+
+static int veth_xsk_umem_disable(struct net_device *dev,
+ u16 qid)
+{
+ struct veth_priv *priv = netdev_priv(dev);
+
+ if (!priv->xsk_umems || qid >= priv->num_xsk_umems ||
+ !priv->xsk_umems[qid])
+ return -EINVAL;
+
+ veth_remove_xsk_umem(dev, qid);
+ 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 = netdev_priv(dev);
+ struct veth_rq *rq;
+
+ rq = &priv->rq[qid];
+
+ if (qid >= dev->real_num_rx_queues)
+ return -ENXIO;
+
+ if (!priv->xsk_umems)
+ return -ENXIO;
+
+ if (!napi_if_scheduled_mark_missed(&rq->xdp_napi))
+ napi_schedule(&rq->xdp_napi);
+
+ return 0;
+}
+
static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
{
switch (xdp->command) {
@@ -1123,6 +1345,26 @@ 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 XDP on both sides */
+ 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 +1387,7 @@ 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 | \
--
2.7.4
