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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>
This commit is contained in:
Jesse Brandeburg 2006-09-27 12:53:48 -07:00 committed by Auke Kok
parent 249d71d694
commit 65c7973fa5
1 changed files with 42 additions and 10 deletions
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52
drivers/net/e1000/e1000_main.c
View File

@ -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) {