From 4b95fe3de7f25402b22cd4d8b20b99cce1979309 Mon Sep 17 00:00:00 2001 From: Emil Tantilov Date: Sat, 8 Nov 2014 01:39:41 +0000 Subject: [PATCH] ixgbevf: Update Rx next to clean in real time Since the next_to_clean value is only accessed by the Rx interrupt handler we can save on stack space by just storing our updated values back in next_to_clean instead of using the stack variable i. This should help to reduce stack space and we can further collapse the size of the function. Also removed non_eop_descs counter as it was never shown in the stats. CC: Alexander Duyck Signed-off-by: Emil Tantilov Tested-by: Phil Schmitt Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/ixgbevf/ixgbevf.h | 2 - .../net/ethernet/intel/ixgbevf/ixgbevf_main.c | 55 ++++++++++++------- 2 files changed, 36 insertions(+), 21 deletions(-) diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h index 90d5751b7f92..72a354b2128e 100644 --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h @@ -79,7 +79,6 @@ struct ixgbevf_tx_queue_stats { }; struct ixgbevf_rx_queue_stats { - u64 non_eop_descs; u64 alloc_rx_page_failed; u64 alloc_rx_buff_failed; u64 csum_err; @@ -372,7 +371,6 @@ struct ixgbevf_adapter { struct ixgbevf_ring *rx_ring[MAX_TX_QUEUES]; /* One per active queue */ u64 hw_csum_rx_error; u64 hw_rx_no_dma_resources; - u64 non_eop_descs; int num_msix_vectors; u32 alloc_rx_page_failed; u32 alloc_rx_buff_failed; diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c index 220699285021..20bebd212ac2 100644 --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c @@ -410,6 +410,35 @@ static void ixgbevf_process_skb_fields(struct ixgbevf_ring *rx_ring, skb->protocol = eth_type_trans(skb, rx_ring->netdev); } +/** + * ixgbevf_is_non_eop - process handling of non-EOP buffers + * @rx_ring: Rx ring being processed + * @rx_desc: Rx descriptor for current buffer + * @skb: current socket buffer containing buffer in progress + * + * This function updates next to clean. If the buffer is an EOP buffer + * this function exits returning false, otherwise it will place the + * sk_buff in the next buffer to be chained and return true indicating + * that this is in fact a non-EOP buffer. + **/ +static bool ixgbevf_is_non_eop(struct ixgbevf_ring *rx_ring, + union ixgbe_adv_rx_desc *rx_desc, + struct sk_buff *skb) +{ + u32 ntc = rx_ring->next_to_clean + 1; + + /* fetch, update, and store next to clean */ + ntc = (ntc < rx_ring->count) ? ntc : 0; + rx_ring->next_to_clean = ntc; + + prefetch(IXGBEVF_RX_DESC(rx_ring, ntc)); + + if (likely(ixgbevf_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP))) + return false; + + return true; +} + static bool ixgbevf_alloc_mapped_skb(struct ixgbevf_ring *rx_ring, struct ixgbevf_rx_buffer *bi) { @@ -517,16 +546,14 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector, struct ixgbevf_ring *rx_ring, int budget) { - unsigned int i; unsigned int total_rx_bytes = 0, total_rx_packets = 0; u16 cleaned_count = ixgbevf_desc_unused(rx_ring); - i = rx_ring->next_to_clean; - do { - union ixgbe_adv_rx_desc *rx_desc, *next_rxd; + union ixgbe_adv_rx_desc *rx_desc; struct ixgbevf_rx_buffer *rx_buffer; struct sk_buff *skb; + u16 ntc; /* return some buffers to hardware, one at a time is too slow */ if (cleaned_count >= IXGBEVF_RX_BUFFER_WRITE) { @@ -534,8 +561,9 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector, cleaned_count = 0; } - rx_desc = IXGBEVF_RX_DESC(rx_ring, i); - rx_buffer = &rx_ring->rx_buffer_info[i]; + ntc = rx_ring->next_to_clean; + rx_desc = IXGBEVF_RX_DESC(rx_ring, ntc); + rx_buffer = &rx_ring->rx_buffer_info[ntc]; if (!ixgbevf_test_staterr(rx_desc, IXGBE_RXD_STAT_DD)) break; @@ -562,19 +590,9 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector, cleaned_count++; - i++; - if (i == rx_ring->count) - i = 0; - - next_rxd = IXGBEVF_RX_DESC(rx_ring, i); - prefetch(next_rxd); - - if (!(ixgbevf_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP))) { - skb->next = rx_ring->rx_buffer_info[i].skb; - IXGBE_CB(skb->next)->prev = skb; - rx_ring->rx_stats.non_eop_descs++; + /* place incomplete frames back on ring for completion */ + if (ixgbevf_is_non_eop(rx_ring, rx_desc, skb)) continue; - } /* we should not be chaining buffers, if we did drop the skb */ if (IXGBE_CB(skb)->prev) { @@ -617,7 +635,6 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector, budget--; } while (likely(budget)); - rx_ring->next_to_clean = i; u64_stats_update_begin(&rx_ring->syncp); rx_ring->stats.packets += total_rx_packets; rx_ring->stats.bytes += total_rx_bytes; -- 2.20.1