diff options
| author | Alexander Duyck <alexander.h.duyck@intel.com> | 2012-09-13 06:28:01 +0000 |
|---|---|---|
| committer | Jeff Kirsher <jeffrey.t.kirsher@intel.com> | 2012-09-22 02:50:24 -0700 |
| commit | f4128785b8f3f1fd7dc81b972661003d639a4676 (patch) | |
| tree | 8d34f8c4b12cf6032fe135d073319c94af96c79c | |
| parent | f33005a637bffca72fe373d1e91f2dfbc8fae157 (diff) | |
igb: Change Tx cleanup loop to do/while instead of for
This change makes it so that Tx cleanup is done in a do/while loop instead
of a for loop. The main motivation behind this is the fact that we should
never be invoked with a budget less than 1 so we can skip checking the
budget before processing the first descriptor.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
| -rw-r--r-- | drivers/net/ethernet/intel/igb/igb_main.c | 28 |
1 files changed, 16 insertions, 12 deletions
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c index c9997d83de07..91f542c50f61 100644 --- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -5690,7 +5690,7 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector) struct igb_adapter *adapter = q_vector->adapter; struct igb_ring *tx_ring = q_vector->tx.ring; struct igb_tx_buffer *tx_buffer; - union e1000_adv_tx_desc *tx_desc, *eop_desc; + union e1000_adv_tx_desc *tx_desc; unsigned int total_bytes = 0, total_packets = 0; unsigned int budget = q_vector->tx.work_limit; unsigned int i = tx_ring->next_to_clean; @@ -5702,16 +5702,16 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector) tx_desc = IGB_TX_DESC(tx_ring, i); i -= tx_ring->count; - for (; budget; budget--) { - eop_desc = tx_buffer->next_to_watch; - - /* prevent any other reads prior to eop_desc */ - rmb(); + do { + union e1000_adv_tx_desc *eop_desc = tx_buffer->next_to_watch; /* if next_to_watch is not set then there is no work pending */ if (!eop_desc) break; + /* prevent any other reads prior to eop_desc */ + rmb(); + /* if DD is not set pending work has not been completed */ if (!(eop_desc->wb.status & cpu_to_le32(E1000_TXD_STAT_DD))) break; @@ -5767,7 +5767,13 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector) tx_buffer = tx_ring->tx_buffer_info; tx_desc = IGB_TX_DESC(tx_ring, 0); } - } + + /* issue prefetch for next Tx descriptor */ + prefetch(tx_desc); + + /* update budget accounting */ + budget--; + } while (likely(budget)); netdev_tx_completed_queue(txring_txq(tx_ring), total_packets, total_bytes); @@ -5783,12 +5789,10 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector) if (test_bit(IGB_RING_FLAG_TX_DETECT_HANG, &tx_ring->flags)) { struct e1000_hw *hw = &adapter->hw; - eop_desc = tx_buffer->next_to_watch; - /* Detect a transmit hang in hardware, this serializes the * check with the clearing of time_stamp and movement of i */ clear_bit(IGB_RING_FLAG_TX_DETECT_HANG, &tx_ring->flags); - if (eop_desc && + if (tx_buffer->next_to_watch && time_after(jiffies, tx_buffer->time_stamp + (adapter->tx_timeout_factor * HZ)) && !(rd32(E1000_STATUS) & E1000_STATUS_TXOFF)) { @@ -5812,9 +5816,9 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector) tx_ring->next_to_use, tx_ring->next_to_clean, tx_buffer->time_stamp, - eop_desc, + tx_buffer->next_to_watch, jiffies, - eop_desc->wb.status); + tx_buffer->next_to_watch->wb.status); netif_stop_subqueue(tx_ring->netdev, tx_ring->queue_index); |