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Date: Tue, 18 Nov 2014 20:10:47 -0800
From: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To: davem@...emloft.net
Cc: Emil Tantilov <emil.s.tantilov@...el.com>, netdev@...r.kernel.org,
nhorman@...hat.com, sassmann@...hat.com, jogreene@...hat.com,
Alexander Duyck <alexander.h.duyck@...hat.com>,
Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [net-next 06/15] ixgbevf: Update Rx next to clean in real time
From: Emil Tantilov <emil.s.tantilov@...el.com>
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@...hat.com>
Signed-off-by: Emil Tantilov <emil.s.tantilov@...el.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@...el.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---
drivers/net/ethernet/intel/ixgbevf/ixgbevf.h | 2 -
drivers/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 90d5751..72a354b 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 2206992..20bebd2 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;
--
1.9.3
--
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