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ixgbevf: Update Rx next to clean in real time

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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 <alexander.h.duyck@redhat.com>
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
This commit is contained in:
Emil Tantilov 2014-11-08 01:39:41 +00:00 committed by Jeff Kirsher
parent 0579eefca7
commit 4b95fe3de7
2 changed files with 36 additions and 21 deletions
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2
drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
View file

@ -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;

55
drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
View file

@ -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;