On Sat, Aug 05, 2006 at 07:36:50PM -0400, jamal wrote: > > I know the qlen is >= 0 otherwise i will hit the BUG(). > A qlen of 0 will be interesting to find as well.
When the queue is woken it will always to qdisc_run regardless of whether there are packets queued so this might explain what you're seeing. Anyway, I've changed the unconditional atomic op into a memory barrier instead. Let me know if this changes things for you. I wonder if we could do the TX clean up within the transmission routine most of the time. Has anyone tried this before? Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} <[EMAIL PROTECTED]> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c index 627f224..e7e1306 100644 --- a/drivers/net/e1000/e1000_main.c +++ b/drivers/net/e1000/e1000_main.c @@ -2861,6 +2861,33 @@ e1000_transfer_dhcp_info(struct e1000_ad return 0; } +static int __e1000_maybe_stop_tx(struct net_device *netdev, int size) +{ + struct e1000_adapter *adapter = netdev_priv(netdev); + struct e1000_tx_ring *tx_ring = adapter->tx_ring; + + netif_stop_queue(netdev); + smp_mb__after_netif_stop_queue(); + + /* We need to check again in a case another CPU has just + * made room available. + */ + if (likely(E1000_DESC_UNUSED(tx_ring) < size)) + return -EBUSY; + + /* A reprieve! */ + netif_start_queue(netdev); + return 0; +} + +static inline int e1000_maybe_stop_tx(struct net_device *netdev, + struct e1000_tx_ring *tx_ring, int size) +{ + if (likely(E1000_DESC_UNUSED(tx_ring) >= size)) + return 0; + return __e1000_maybe_stop_tx(netdev, size); +} + #define TXD_USE_COUNT(S, X) (((S) >> (X)) + 1 ) static int e1000_xmit_frame(struct sk_buff *skb, struct net_device *netdev) @@ -2974,8 +3001,7 @@ #endif /* need: count + 2 desc gap to keep tail from touching * head, otherwise try next time */ - if (unlikely(E1000_DESC_UNUSED(tx_ring) < count + 2)) { - netif_stop_queue(netdev); + if (unlikely(e1000_maybe_stop_tx(netdev, tx_ring, count + 2))) { spin_unlock_irqrestore(&tx_ring->tx_lock, flags); return NETDEV_TX_BUSY; } @@ -3022,8 +3048,7 @@ #endif netdev->trans_start = jiffies; /* Make sure there is space in the ring for the next send. */ - if (unlikely(E1000_DESC_UNUSED(tx_ring) < MAX_SKB_FRAGS + 2)) - netif_stop_queue(netdev); + e1000_maybe_stop_tx(netdev, tx_ring, MAX_SKB_FRAGS + 2); spin_unlock_irqrestore(&tx_ring->tx_lock, flags); return NETDEV_TX_OK; @@ -3515,13 +3540,14 @@ #endif tx_ring->next_to_clean = i; #define TX_WAKE_THRESHOLD 32 - if (unlikely(cleaned && netif_queue_stopped(netdev) && - netif_carrier_ok(netdev))) { - spin_lock(&tx_ring->tx_lock); - if (netif_queue_stopped(netdev) && - (E1000_DESC_UNUSED(tx_ring) >= TX_WAKE_THRESHOLD)) + if (unlikely(cleaned && netif_carrier_ok(netdev) && + E1000_DESC_UNUSED(tx_ring) >= TX_WAKE_THRESHOLD)) { + /* Make sure that anybody stopping the queue after this + * sees the new next_to_clean. + */ + smp_mb(); + if (netif_queue_stopped(netdev)) netif_wake_queue(netdev); - spin_unlock(&tx_ring->tx_lock); } if (adapter->detect_tx_hung) { diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 75f02d8..7daaf71 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -33,6 +33,7 @@ #ifdef __KERNEL__ #include <asm/atomic.h> #include <asm/cache.h> #include <asm/byteorder.h> +#include <asm/system.h> #include <linux/device.h> #include <linux/percpu.h> @@ -652,6 +653,12 @@ #endif set_bit(__LINK_STATE_XOFF, &dev->state); } +static inline void smp_mb__after_netif_stop_queue(void) +{ + /* Need to add smp_mb__after_set_bit(). */ + smp_mb(); +} + static inline int netif_queue_stopped(const struct net_device *dev) { return test_bit(__LINK_STATE_XOFF, &dev->state); - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
