diff options
| author | Jesse Brandeburg <jesse.brandeburg@intel.com> | 2006-09-27 12:53:48 -0700 |
|---|---|---|
| committer | Auke Kok <juke-jan.h.kok@intel.com> | 2006-09-27 12:53:48 -0700 |
| commit | 65c7973fa5b46b024f38be208aa477e8daf9a603 (patch) | |
| tree | 8eee88280564b166cd44380b3b4bf3df04b46225 /drivers/net/e1000 | |
| parent | 249d71d694ee3a6c02067235995d6d4258d364f3 (diff) | |
e1000: Maybe stop TX if not enough free descriptors
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Diffstat (limited to 'drivers/net/e1000')
| -rw-r--r-- | drivers/net/e1000/e1000_main.c | 52 |
1 files changed, 42 insertions, 10 deletions
diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c index a1f5b060536..e8a76080207 100644 --- a/drivers/net/e1000/e1000_main.c +++ b/drivers/net/e1000/e1000_main.c @@ -2899,6 +2899,35 @@ e1000_transfer_dhcp_info(struct e1000_adapter *adapter, struct sk_buff *skb) 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); + /* Herbert's original patch had: + * smp_mb__after_netif_stop_queue(); + * but since that doesn't exist yet, just open code it. */ + smp_mb(); + + /* 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 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) @@ -2917,6 +2946,10 @@ e1000_xmit_frame(struct sk_buff *skb, struct net_device *netdev) unsigned int f; len -= skb->data_len; + /* This goes back to the question of how to logically map a tx queue + * to a flow. Right now, performance is impacted slightly negatively + * if using multiple tx queues. If the stack breaks away from a + * single qdisc implementation, we can look at this again. */ tx_ring = adapter->tx_ring; if (unlikely(skb->len <= 0)) { @@ -3012,8 +3045,7 @@ e1000_xmit_frame(struct sk_buff *skb, struct net_device *netdev) /* 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; } @@ -3060,8 +3092,7 @@ e1000_xmit_frame(struct sk_buff *skb, struct net_device *netdev) 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; @@ -3556,13 +3587,14 @@ e1000_clean_tx_irq(struct e1000_adapter *adapter, 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) { |