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Commit b97fe3b1 authored by Emil Tantilov's avatar Emil Tantilov Committed by Jeff Kirsher
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ixgbevf: Cleanup variable usage, improve stack performance 



This change is meant to help cleanup the usage of temporary variables
within the Rx hot-path by removing unnecessary variables and reducing
the scope of variables that do not need to exist outside the main loop.

CC: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: default avatarEmil Tantilov <emil.s.tantilov@intel.com>
Tested-by: default avatarPhil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent dff80520

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c

+11 −9
Original line number Original line Diff line number Diff line
@@ -517,26 +517,28 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector, 
				struct ixgbevf_ring *rx_ring,

				struct ixgbevf_ring *rx_ring,

				int budget)

				int budget)

{

{

	union ixgbe_adv_rx_desc *rx_desc, *next_rxd;

	union ixgbe_adv_rx_desc *rx_desc;

	struct ixgbevf_rx_buffer *rx_buffer_info, *next_buffer;

	struct sk_buff *skb;

	unsigned int i;

	unsigned int i;

	unsigned int total_rx_bytes = 0, total_rx_packets = 0;

	unsigned int total_rx_bytes = 0, total_rx_packets = 0;

	u16 cleaned_count = ixgbevf_desc_unused(rx_ring);

	u16 cleaned_count = ixgbevf_desc_unused(rx_ring);





	i = rx_ring->next_to_clean;

	i = rx_ring->next_to_clean;

	rx_desc = IXGBEVF_RX_DESC(rx_ring, i);

	rx_desc = IXGBEVF_RX_DESC(rx_ring, i);

	rx_buffer_info = &rx_ring->rx_buffer_info[i];





	while (ixgbevf_test_staterr(rx_desc, IXGBE_RXD_STAT_DD)) {

	while (ixgbevf_test_staterr(rx_desc, IXGBE_RXD_STAT_DD)) {

		union ixgbe_adv_rx_desc *next_rxd;

		struct ixgbevf_rx_buffer *rx_buffer_info;

		struct sk_buff *skb;



		if (!budget)

		if (!budget)

			break;

			break;

		budget--;

		budget--;





		rmb(); /* read descriptor and rx_buffer_info after status DD */

		rmb(); /* read descriptor and rx_buffer_info after status DD */





		rx_buffer_info = &rx_ring->rx_buffer_info[i];

		skb = rx_buffer_info->skb;

		skb = rx_buffer_info->skb;

		prefetch(skb->data - NET_IP_ALIGN);

		prefetch(skb->data);

		rx_buffer_info->skb = NULL;

		rx_buffer_info->skb = NULL;





		dma_unmap_single(rx_ring->dev, rx_buffer_info->dma,

		dma_unmap_single(rx_ring->dev, rx_buffer_info->dma,
@@ -545,18 +547,17 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector, 
		rx_buffer_info->dma = 0;

		rx_buffer_info->dma = 0;

		skb_put(skb, le16_to_cpu(rx_desc->wb.upper.length));

		skb_put(skb, le16_to_cpu(rx_desc->wb.upper.length));





		cleaned_count++;



		i++;

		i++;

		if (i == rx_ring->count)

		if (i == rx_ring->count)

			i = 0;

			i = 0;





		next_rxd = IXGBEVF_RX_DESC(rx_ring, i);

		next_rxd = IXGBEVF_RX_DESC(rx_ring, i);

		prefetch(next_rxd);

		prefetch(next_rxd);

		cleaned_count++;



		next_buffer = &rx_ring->rx_buffer_info[i];





		if (!(ixgbevf_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP))) {

		if (!(ixgbevf_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP))) {

			skb->next = next_buffer->skb;

			skb->next = rx_ring->rx_buffer_info[i].skb;

			IXGBE_CB(skb->next)->prev = skb;

			IXGBE_CB(skb->next)->prev = skb;

			rx_ring->rx_stats.non_eop_descs++;

			rx_ring->rx_stats.non_eop_descs++;

			goto next_desc;

			goto next_desc;
@@ -609,6 +610,7 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector, 
		/* use prefetched values */

		/* use prefetched values */

		rx_desc = next_rxd;

		rx_desc = next_rxd;

		rx_buffer_info = &rx_ring->rx_buffer_info[i];

		rx_buffer_info = &rx_ring->rx_buffer_info[i];

		rx_desc = IXGBEVF_RX_DESC(rx_ring, i);

	}

	}





	rx_ring->next_to_clean = i;

	rx_ring->next_to_clean = i;