diff options
Diffstat (limited to 'drivers/net')
| -rw-r--r-- | drivers/net/ethernet/intel/i40e/i40e_txrx.c | 9 | ||||
| -rw-r--r-- | drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 9 |
2 files changed, 18 insertions, 0 deletions
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index 616abf79253e..a23306f04e00 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -1372,6 +1372,15 @@ bool i40e_alloc_rx_buffers(struct i40e_ring *rx_ring, u16 cleaned_count) union i40e_rx_desc *rx_desc; struct i40e_rx_buffer *bi; + /* Hardware only fetches new descriptors in cache lines of 8, + * essentially ignoring the lower 3 bits of the tail register. We want + * to ensure our tail writes are aligned to avoid unnecessary work. We + * can't simply round down the cleaned count, since we might fail to + * allocate some buffers. What we really want is to ensure that + * next_to_used + cleaned_count produces an aligned value. + */ + cleaned_count -= (ntu + cleaned_count) & 0x7; + /* do nothing if no valid netdev defined */ if (!rx_ring->netdev || !cleaned_count) return false; diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c index fe817e2b6fef..6806ada11490 100644 --- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c @@ -711,6 +711,15 @@ bool i40evf_alloc_rx_buffers(struct i40e_ring *rx_ring, u16 cleaned_count) union i40e_rx_desc *rx_desc; struct i40e_rx_buffer *bi; + /* Hardware only fetches new descriptors in cache lines of 8, + * essentially ignoring the lower 3 bits of the tail register. We want + * to ensure our tail writes are aligned to avoid unnecessary work. We + * can't simply round down the cleaned count, since we might fail to + * allocate some buffers. What we really want is to ensure that + * next_to_used + cleaned_count produces an aligned value. + */ + cleaned_count -= (ntu + cleaned_count) & 0x7; + /* do nothing if no valid netdev defined */ if (!rx_ring->netdev || !cleaned_count) return false; |