[dpdk-dev] [PATCH 1/2] net/af_xdp: fix trigger for syscall on tx

[Ciara Loftus]

The send() syscall on the tx path is not concerned with busy polling
and as such its invocation should not depend on whether or not it is
configured. Fix this by distinguishing the conditions necessary for
syscalls on the rx and tx paths individually.

Fixes: 055a393626ed ("net/af_xdp: prefer busy polling")

Signed-off-by: Ciara Loftus <ciara.lof...@intel.com>
---
 drivers/net/af_xdp/compat.h         | 14 ++++++++++++--
 drivers/net/af_xdp/rte_eth_af_xdp.c |  4 ++--
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/net/af_xdp/compat.h b/drivers/net/af_xdp/compat.h
index 545c8aa395..9de9454885 100644
--- a/drivers/net/af_xdp/compat.h
+++ b/drivers/net/af_xdp/compat.h
@@ -42,14 +42,24 @@ create_shared_socket(struct xsk_socket **xsk_ptr 
__rte_unused,
 
 #ifdef XDP_USE_NEED_WAKEUP
 static int
-syscall_needed(struct xsk_ring_prod *q, uint32_t busy_budget)
+rx_syscall_needed(struct xsk_ring_prod *q, uint32_t busy_budget)
 {
        return xsk_ring_prod__needs_wakeup(q) | busy_budget;
 }
+static int
+tx_syscall_needed(struct xsk_ring_prod *q)
+{
+       return xsk_ring_prod__needs_wakeup(q);
+}
 #else
 static int
-syscall_needed(struct xsk_ring_prod *q __rte_unused, uint32_t busy_budget)
+rx_syscall_needed(struct xsk_ring_prod *q __rte_unused, uint32_t busy_budget)
 {
        return busy_budget;
 }
+static int
+tx_syscall_needed(struct xsk_ring_prod *q __rte_unused)
+{
+       return 1;
+}
 #endif
diff --git a/drivers/net/af_xdp/rte_eth_af_xdp.c 
b/drivers/net/af_xdp/rte_eth_af_xdp.c
index 6e44a21c64..8c6cd224a8 100644
--- a/drivers/net/af_xdp/rte_eth_af_xdp.c
+++ b/drivers/net/af_xdp/rte_eth_af_xdp.c
@@ -273,7 +273,7 @@ af_xdp_rx_zc(void *queue, struct rte_mbuf **bufs, uint16_t 
nb_pkts)
        nb_pkts = xsk_ring_cons__peek(rx, nb_pkts, &idx_rx);
 
        if (nb_pkts == 0) {
-               if (syscall_needed(&rxq->fq, rxq->busy_budget))
+               if (rx_syscall_needed(&rxq->fq, rxq->busy_budget))
                        (void)recvfrom(xsk_socket__fd(rxq->xsk), NULL, 0,
                                MSG_DONTWAIT, NULL, NULL);
 
@@ -456,7 +456,7 @@ kick_tx(struct pkt_tx_queue *txq, struct xsk_ring_cons *cq)
 
        pull_umem_cq(umem, XSK_RING_CONS__DEFAULT_NUM_DESCS, cq);
 
-       if (syscall_needed(&txq->tx, txq->pair->busy_budget))
+       if (tx_syscall_needed(&txq->tx))
                while (send(xsk_socket__fd(txq->pair->xsk), NULL,
                            0, MSG_DONTWAIT) < 0) {
                        /* some thing unexpected */
-- 
2.25.1