ixgbe: fix Tx timeouts with BQL

This patch makes sure that TXDCTL.WTHRESH is set to 1 when BQL is enabled
and EITR is set to more than 100k interrupts per second to avoid Tx timeouts.

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
index e6cebdc..f4d2e9e 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
@@ -2113,13 +2113,17 @@ static int ixgbe_set_coalesce(struct net_device *netdev,
        struct ixgbe_adapter *adapter = netdev_priv(netdev);
        struct ixgbe_q_vector *q_vector;
        int i;
-       u16 tx_itr_param, rx_itr_param;
+       u16 tx_itr_param, rx_itr_param, tx_itr_prev;
        bool need_reset = false;
 
-       /* don't accept tx specific changes if we've got mixed RxTx vectors */
-       if (adapter->q_vector[0]->tx.count && adapter->q_vector[0]->rx.count
-           && ec->tx_coalesce_usecs)
-               return -EINVAL;
+       if (adapter->q_vector[0]->tx.count && adapter->q_vector[0]->rx.count) {
+               /* reject Tx specific changes in case of mixed RxTx vectors */
+               if (ec->tx_coalesce_usecs)
+                       return -EINVAL;
+               tx_itr_prev = adapter->rx_itr_setting;
+       } else {
+               tx_itr_prev = adapter->tx_itr_setting;
+       }
 
        if ((ec->rx_coalesce_usecs > (IXGBE_MAX_EITR >> 2)) ||
            (ec->tx_coalesce_usecs > (IXGBE_MAX_EITR >> 2)))
@@ -2145,8 +2149,25 @@ static int ixgbe_set_coalesce(struct net_device *netdev,
        else
                tx_itr_param = adapter->tx_itr_setting;
 
+       /* mixed Rx/Tx */
+       if (adapter->q_vector[0]->tx.count && adapter->q_vector[0]->rx.count)
+               adapter->tx_itr_setting = adapter->rx_itr_setting;
+
+#if IS_ENABLED(CONFIG_BQL)
+       /* detect ITR changes that require update of TXDCTL.WTHRESH */
+       if ((adapter->tx_itr_setting > 1) &&
+           (adapter->tx_itr_setting < IXGBE_100K_ITR)) {
+               if ((tx_itr_prev == 1) ||
+                   (tx_itr_prev > IXGBE_100K_ITR))
+                       need_reset = true;
+       } else {
+               if ((tx_itr_prev > 1) &&
+                   (tx_itr_prev < IXGBE_100K_ITR))
+                       need_reset = true;
+       }
+#endif
        /* check the old value and enable RSC if necessary */
-       need_reset = ixgbe_update_rsc(adapter);
+       need_reset |= ixgbe_update_rsc(adapter);
 
        for (i = 0; i < adapter->num_q_vectors; i++) {
                q_vector = adapter->q_vector[i];

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index b0b72fc..68478d6 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -2786,13 +2786,19 @@ void ixgbe_configure_tx_ring(struct ixgbe_adapter *adapter,
 
        /*
         * set WTHRESH to encourage burst writeback, it should not be set
-        * higher than 1 when ITR is 0 as it could cause false TX hangs
+        * higher than 1 when:
+        * - ITR is 0 as it could cause false TX hangs
+        * - ITR is set to > 100k int/sec and BQL is enabled
         *
         * In order to avoid issues WTHRESH + PTHRESH should always be equal
         * to or less than the number of on chip descriptors, which is
         * currently 40.
         */
+#if IS_ENABLED(CONFIG_BQL)
+       if (!ring->q_vector || (ring->q_vector->itr < IXGBE_100K_ITR))
+#else
        if (!ring->q_vector || (ring->q_vector->itr < 8))
+#endif
                txdctl |= (1 << 16);    /* WTHRESH = 1 */
        else
                txdctl |= (8 << 16);    /* WTHRESH = 8 */