diff options
| author | Michael Chan <mchan@broadcom.com> | 2005-09-01 17:41:28 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2005-09-01 17:41:28 -0700 |
| commit | 51b9146869ab9492da785c5c9321d85f01655ab6 (patch) | |
| tree | d95f8fda63a7e4a2508f1fc440dcc5e162140334 | |
| parent | 86d9f7f0c9cf06d7d3cfa2a9f0514cf21fa5fda1 (diff) | |
| download | lwn-51b9146869ab9492da785c5c9321d85f01655ab6.tar.gz lwn-51b9146869ab9492da785c5c9321d85f01655ab6.zip | |
[TG3]: Minimize locking in TX path.
This is similar to Eric Dumazet's tx_lock patch for tg3 but takes it
one step further to eliminate the tx_lock in the tx_completion path
when the tx queue is not stopped.
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/tg3.c | 24 |
1 files changed, 13 insertions, 11 deletions
diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c index af8263a1580e..e877579aab38 100644 --- a/drivers/net/tg3.c +++ b/drivers/net/tg3.c @@ -121,12 +121,9 @@ TG3_RX_RCB_RING_SIZE(tp)) #define TG3_TX_RING_BYTES (sizeof(struct tg3_tx_buffer_desc) * \ TG3_TX_RING_SIZE) -#define TX_RING_GAP(TP) \ - (TG3_TX_RING_SIZE - (TP)->tx_pending) #define TX_BUFFS_AVAIL(TP) \ - (((TP)->tx_cons <= (TP)->tx_prod) ? \ - (TP)->tx_cons + (TP)->tx_pending - (TP)->tx_prod : \ - (TP)->tx_cons - (TP)->tx_prod - TX_RING_GAP(TP)) + ((TP)->tx_pending - \ + (((TP)->tx_prod - (TP)->tx_cons) & (TG3_TX_RING_SIZE - 1))) #define NEXT_TX(N) (((N) + 1) & (TG3_TX_RING_SIZE - 1)) #define RX_PKT_BUF_SZ (1536 + tp->rx_offset + 64) @@ -2880,9 +2877,13 @@ static void tg3_tx(struct tg3 *tp) tp->tx_cons = sw_idx; - if (netif_queue_stopped(tp->dev) && - (TX_BUFFS_AVAIL(tp) > TG3_TX_WAKEUP_THRESH)) - netif_wake_queue(tp->dev); + if (unlikely(netif_queue_stopped(tp->dev))) { + spin_lock(&tp->tx_lock); + if (netif_queue_stopped(tp->dev) && + (TX_BUFFS_AVAIL(tp) > TG3_TX_WAKEUP_THRESH)) + netif_wake_queue(tp->dev); + spin_unlock(&tp->tx_lock); + } } /* Returns size of skb allocated or < 0 on error. @@ -3198,9 +3199,7 @@ static int tg3_poll(struct net_device *netdev, int *budget) /* run TX completion thread */ if (sblk->idx[0].tx_consumer != tp->tx_cons) { - spin_lock(&tp->tx_lock); tg3_tx(tp); - spin_unlock(&tp->tx_lock); } /* run RX thread, within the bounds set by NAPI. @@ -3716,8 +3715,11 @@ static int tg3_start_xmit(struct sk_buff *skb, struct net_device *dev) tw32_tx_mbox((MAILBOX_SNDHOST_PROD_IDX_0 + TG3_64BIT_REG_LOW), entry); tp->tx_prod = entry; - if (TX_BUFFS_AVAIL(tp) <= (MAX_SKB_FRAGS + 1)) + if (TX_BUFFS_AVAIL(tp) <= (MAX_SKB_FRAGS + 1)) { netif_stop_queue(dev); + if (TX_BUFFS_AVAIL(tp) > TG3_TX_WAKEUP_THRESH) + netif_wake_queue(tp->dev); + } out_unlock: mmiowb(); |