igb: avoid transmit queue timeout in xdp path

Since we share the transmit queue with the network stack,
it is possible that we run into a transmit queue timeout.
This will reset the queue.
This happens under high load when XDP is using the
transmit queue pretty much exclusively.

netdev_start_xmit() sets the trans_start variable of the
transmit queue to jiffies which is later utilized by dev_watchdog(),
so to avoid timeout, let stack know that XDP xmit happened by
bumping the trans_start within XDP Tx routines to jiffies.

Fixes: 9cbc948b5a20 ("igb: add XDP support")
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Sven Auhagen <sven.auhagen@voleatech.de>
Tested-by: Sandeep Penigalapati <sandeep.penigalapati@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index af6ace6..0d343d0 100644 (file)
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -2919,6 +2919,8 @@ static int igb_xdp_xmit_back(struct igb_adapter *adapter, struct xdp_buff *xdp)
 
        nq = txring_txq(tx_ring);
        __netif_tx_lock(nq, cpu);
+       /* Avoid transmit queue timeout since we share it with the slow path */
+       nq->trans_start = jiffies;
        ret = igb_xmit_xdp_ring(adapter, tx_ring, xdpf);
        __netif_tx_unlock(nq);
 
@@ -2951,6 +2953,9 @@ static int igb_xdp_xmit(struct net_device *dev, int n,
        nq = txring_txq(tx_ring);
        __netif_tx_lock(nq, cpu);
 
+       /* Avoid transmit queue timeout since we share it with the slow path */
+       nq->trans_start = jiffies;
+
        for (i = 0; i < n; i++) {
                struct xdp_frame *xdpf = frames[i];
                int err;