> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-boun...@osuosl.org> On Behalf Of
> Maciej Fijalkowski
> Sent: Tuesday, April 29, 2025 5:52 PM
> To: intel-wired-...@lists.osuosl.org
> Cc: net...@vger.kernel.org; Nguyen, Anthony L
> <anthony.l.ngu...@intel.com>; Karlsson, Magnus
> <magnus.karls...@intel.com>; Kubiak, Michal <michal.kub...@intel.com>;
> Fijalkowski, Maciej <maciej.fijalkow...@intel.com>; Tobias Böhm
> <tobias.bo...@hetzner-cloud.de>; Marcus Wichelmann
> <marcus.wichelm...@hetzner-cloud.de>
> Subject: [Intel-wired-lan] [PATCH iwl-net] ixgbe: fix ndo_xdp_xmit() workloads
>
> Currently ixgbe driver checks periodically in its watchdog subtask if there is
> anything to be transmitted (consdidering both Tx and XDP rings) under state
> of carrier not being 'ok'. Such event is interpreted as Tx hang and therefore
> results in interface reset.
>
> This is currently problematic for ndo_xdp_xmit() as it is allowed to produce
> descriptors when interface is going through reset or its carrier is turned
> off.
>
> Furthermore, XDP rings should not really be objects of Tx hang detection. This
> mechanism is rather a matter of ndo_tx_timeout() being called from
> dev_watchdog against Tx rings exposed to networking stack.
>
> Taking into account issues described above, let us have a two fold fix - do
> not
> respect XDP rings in local ixgbe watchdog and do not produce Tx descriptors in
> ndo_xdp_xmit callback when there is some problem with carrier currently. For
> now, keep the Tx hang checks in clean Tx irq routine, but adjust it to not
> execute it for XDP rings.
>
> Cc: Tobias Böhm <tobias.bo...@hetzner-cloud.de>
> Reported-by: Marcus Wichelmann <marcus.wichelm...@hetzner-cloud.de>
> Closes: https://lore.kernel.org/netdev/eca1880f-253a-4955-afe6-
> 732d7c692...@hetzner-cloud.de/
> Fixes: 6453073987ba ("ixgbe: add initial support for xdp redirect")
> Fixes: 33fdc82f0883 ("ixgbe: add support for XDP_TX action")
> Signed-off-by: Maciej Fijalkowski <maciej.fijalkow...@intel.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktio...@intel.com>
> ---
> drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 34 ++++++-------------
> 1 file changed, 11 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> index 467f81239e12..21bfea8aeb67 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> @@ -966,10 +966,6 @@ static void ixgbe_update_xoff_rx_lfc(struct
> ixgbe_adapter *adapter)
> for (i = 0; i < adapter->num_tx_queues; i++)
> clear_bit(__IXGBE_HANG_CHECK_ARMED,
> &adapter->tx_ring[i]->state);
> -
> - for (i = 0; i < adapter->num_xdp_queues; i++)
> - clear_bit(__IXGBE_HANG_CHECK_ARMED,
> - &adapter->xdp_ring[i]->state);
> }
>
> static void ixgbe_update_xoff_received(struct ixgbe_adapter *adapter) @@ -
> 1263,10 +1259,13 @@ static bool ixgbe_clean_tx_irq(struct ixgbe_q_vector
> *q_vector,
> total_bytes);
> adapter->tx_ipsec += total_ipsec;
>
> + if (ring_is_xdp(tx_ring))
> + return !!budget;
> +
> if (check_for_tx_hang(tx_ring) && ixgbe_check_tx_hang(tx_ring)) {
> /* schedule immediate reset if we believe we hung */
> struct ixgbe_hw *hw = &adapter->hw;
> - e_err(drv, "Detected Tx Unit Hang %s\n"
> + e_err(drv, "Detected Tx Unit Hang\n"
> " Tx Queue <%d>\n"
> " TDH, TDT <%x>, <%x>\n"
> " next_to_use <%x>\n"
> @@ -1274,16 +1273,14 @@ static bool ixgbe_clean_tx_irq(struct
> ixgbe_q_vector *q_vector,
> "tx_buffer_info[next_to_clean]\n"
> " time_stamp <%lx>\n"
> " jiffies <%lx>\n",
> - ring_is_xdp(tx_ring) ? "(XDP)" : "",
> tx_ring->queue_index,
> IXGBE_READ_REG(hw, IXGBE_TDH(tx_ring->reg_idx)),
> IXGBE_READ_REG(hw, IXGBE_TDT(tx_ring->reg_idx)),
> tx_ring->next_to_use, i,
> tx_ring->tx_buffer_info[i].time_stamp, jiffies);
>
> - if (!ring_is_xdp(tx_ring))
> - netif_stop_subqueue(tx_ring->netdev,
> - tx_ring->queue_index);
> + netif_stop_subqueue(tx_ring->netdev,
> + tx_ring->queue_index);
>
> e_info(probe,
> "tx hang %d detected on queue %d, resetting adapter\n",
> @@ -1296,9 +1293,6 @@ static bool ixgbe_clean_tx_irq(struct
> ixgbe_q_vector *q_vector,
> return true;
> }
>
> - if (ring_is_xdp(tx_ring))
> - return !!budget;
> -
> #define TX_WAKE_THRESHOLD (DESC_NEEDED * 2)
> txq = netdev_get_tx_queue(tx_ring->netdev, tx_ring->queue_index);
> if (!__netif_txq_completed_wake(txq, total_packets, total_bytes, @@
> -7791,12 +7785,9 @@ static void ixgbe_check_hang_subtask(struct
> ixgbe_adapter *adapter)
> return;
>
> /* Force detection of hung controller */
> - if (netif_carrier_ok(adapter->netdev)) {
> + if (netif_carrier_ok(adapter->netdev))
> for (i = 0; i < adapter->num_tx_queues; i++)
> set_check_for_tx_hang(adapter->tx_ring[i]);
> - for (i = 0; i < adapter->num_xdp_queues; i++)
> - set_check_for_tx_hang(adapter->xdp_ring[i]);
> - }
>
> if (!(adapter->flags & IXGBE_FLAG_MSIX_ENABLED)) {
> /*
> @@ -8011,13 +8002,6 @@ static bool ixgbe_ring_tx_pending(struct
> ixgbe_adapter *adapter)
> return true;
> }
>
> - for (i = 0; i < adapter->num_xdp_queues; i++) {
> - struct ixgbe_ring *ring = adapter->xdp_ring[i];
> -
> - if (ring->next_to_use != ring->next_to_clean)
> - return true;
> - }
> -
> return false;
> }
>
> @@ -10742,6 +10726,10 @@ static int ixgbe_xdp_xmit(struct net_device
> *dev, int n,
> if (unlikely(test_bit(__IXGBE_DOWN, &adapter->state)))
> return -ENETDOWN;
>
> + if (!netif_carrier_ok(adapter->netdev) ||
> + !netif_running(adapter->netdev))
> + return -ENETDOWN;
> +
> if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
> return -EINVAL;
>
> --
> 2.43.0
