From b95ed5517354a5f451fb9b3771776ca4c0b65ac3 Mon Sep 17 00:00:00 2001 From: Samiullah Khawaja Date: Fri, 16 May 2025 21:36:38 +0000 Subject: [PATCH] xsk: Bring back busy polling support in XDP_COPY 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. Do the setup of napi_id for XDP_COPY in xsk_bind, as it is done currently for XDP_ZEROCOPY. The setup of napi_id for XDP_COPY in xsk_bind is safe because xsk_rcv_check checks that the rx queue at which the packet arrives is equal to the queue_id that was supplied in bind. This is done for both XDP_COPY and XDP_ZEROCOPY mode. 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/ Enabled socket busy polling using following commands in qemu, ``` sudo ethtool -L eth0 combined 1 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") Signed-off-by: Samiullah Khawaja Reviewed-by: Willem de Bruijn Acked-by: Stanislav Fomichev Signed-off-by: David S. Miller --- net/xdp/xsk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 4abc81f33d3e..72c000c0ae5f 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -1304,7 +1304,7 @@ 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) { + if (qid < dev->real_num_rx_queues) { struct netdev_rx_queue *rxq; rxq = __netif_get_rx_queue(dev, qid); -- 2.20.1