| Message ID | 20201017071238.95190-7-sven.auhagen@voleatech.de (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | igb: xdp patches followup | expand |
On Sat, Oct 17, 2020 at 09:12:38AM +0200, sven.auhagen@voleatech.de wrote: > From: Sven Auhagen <sven.auhagen@voleatech.de> > > Since we share the transmit queue with the slow path, > it is possible that we run into a transmit queue timeout. > This will reset the queue. > This happens under high load when the fast path is using the > transmit queue pretty much exclusively. I'm kinda not leaning towards slow/fast path distinction here, IMHO it would be better to state that transmit queues are shared between network stack and XDP, but that's just a rant. > > By setting the transmit queues trans_start variable to jiffies > in the two xdp xmit functions we avoid the timeout. Probably a few more words of explanation would help here, specifically I would say that netdev_start_xmit() sets trans_start 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. > > Signed-off-by: Sven Auhagen <sven.auhagen@voleatech.de> > --- > drivers/net/ethernet/intel/igb/igb_main.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c > index 55e708f75187..4a082c06f48d 100644 > --- a/drivers/net/ethernet/intel/igb/igb_main.c > +++ b/drivers/net/ethernet/intel/igb/igb_main.c > @@ -2916,6 +2916,8 @@ 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); > > @@ -2948,6 +2950,9 @@ 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; > -- > 2.20.1 >
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c index 55e708f75187..4a082c06f48d 100644 --- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -2916,6 +2916,8 @@ 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); @@ -2948,6 +2950,9 @@ 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;