[PATCH net-next] xsk: Bring back busy polling support in XDP_COPY
From: Samiullah Khawaja <hidden>
Date: 2025-03-25 04:43:59
Subsystem:
networking [general], the rest, xdp sockets (af_xdp) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Magnus Karlsson, Maciej Fijalkowski
Commit 5ef44b3cb43b ("xsk: Bring back busy polling support") fixed the
busy polling support in xsk for XDP_ZEROCOPY after it was broken in
commit 86e25f40aa1e ("net: napi: Add napi_config"). The busy polling
support with XDP_COPY remained broken since the napi_id setup in
xsk_rcv_check was removed.
Bring back the setup of napi_id for XDP_COPY so socket level SO_BUSYPOLL
can be used to poll the underlying napi.
Tested using AF_XDP support in virtio-net by running the xsk_rr AF_XDP
benchmarking tool shared here:
https://lore.kernel.org/all/20250320163523.3501305-1-skhawaja@google.com/T/ (local)
Enabled socket busy polling using following commands in qemu,
sudo ethtool -L eth0 combined 1
sudo ethtool -G eth0 rx 1024
echo 400 | sudo tee /proc/sys/net/core/busy_read
echo 100 | sudo tee /sys/class/net/eth0/napi_defer_hard_irqs
echo 15000 | sudo tee /sys/class/net/eth0/gro_flush_timeout
Fixes: 5ef44b3cb43b ("xsk: Bring back busy polling support")
Fixes: 86e25f40aa1e ("net: napi: Add napi_config")
Signed-off-by: Samiullah Khawaja <redacted>
---
net/xdp/xsk.c | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index e5d104ce7b82..de8bf97b2cb9 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c@@ -310,6 +310,18 @@ static bool xsk_is_bound(struct xdp_sock *xs) return false; } +static void __xsk_mark_napi_id_once(struct sock *sk, struct net_device *dev, u32 qid) +{ + struct netdev_rx_queue *rxq; + + if (qid >= dev->real_num_rx_queues) + return; + + rxq = __netif_get_rx_queue(dev, qid); + if (rxq->napi) + __sk_mark_napi_id_once(sk, rxq->napi->napi_id); +} + static int xsk_rcv_check(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len) { if (!xsk_is_bound(xs))
@@ -323,6 +335,7 @@ static int xsk_rcv_check(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len) return -ENOSPC; } + __xsk_mark_napi_id_once(&xs->sk, xs->dev, xs->queue_id); return 0; }
@@ -1300,13 +1313,8 @@ static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len) xs->queue_id = qid; xp_add_xsk(xs->pool, xs); - if (xs->zc && qid < dev->real_num_rx_queues) { - struct netdev_rx_queue *rxq; - - rxq = __netif_get_rx_queue(dev, qid); - if (rxq->napi) - __sk_mark_napi_id_once(sk, rxq->napi->napi_id); - } + if (xs->zc) + __xsk_mark_napi_id_once(sk, dev, qid); out_unlock: if (err) {
--
2.49.0.395.g12beb8f557-goog