On Thu, Feb 16, 2023 at 07:30:41PM +0530, Tirthendu Sarkar wrote:
> Add a new field called next_to_process in the i40e_ring that is
> advanced for every buffer and change the semantics of next_to_clean to
> point to the first buffer of a packet. Driver will use next_to_process
> in the same way next_to_clean was used previously.
>
> For the non multi-buffer case, next_to_process and next_to_clean will
> always be the same since each packet consists of a single buffer.
>
> Signed-off-by: Tirthendu Sarkar <tirthendu.sarkar@xxxxxxxxx>
> ---
> drivers/net/ethernet/intel/i40e/i40e_txrx.c | 26 ++++++++++++---------
> drivers/net/ethernet/intel/i40e/i40e_txrx.h | 4 ++++
> 2 files changed, 19 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> index 01340f620d96..94c50fa223bd 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> @@ -1524,6 +1524,7 @@ void i40e_clean_rx_ring(struct i40e_ring *rx_ring)
>
> rx_ring->next_to_alloc = 0;
> rx_ring->next_to_clean = 0;
> + rx_ring->next_to_process = 0;
> rx_ring->next_to_use = 0;
> }
>
> @@ -1576,6 +1577,7 @@ int i40e_setup_rx_descriptors(struct i40e_ring *rx_ring)
>
> rx_ring->next_to_alloc = 0;
> rx_ring->next_to_clean = 0;
> + rx_ring->next_to_process = 0;
> rx_ring->next_to_use = 0;
>
> /* XDP RX-queue info only needed for RX rings exposed to XDP */
> @@ -2076,7 +2078,7 @@ static struct i40e_rx_buffer *i40e_get_rx_buffer(struct i40e_ring *rx_ring,
> {
> struct i40e_rx_buffer *rx_buffer;
>
> - rx_buffer = i40e_rx_bi(rx_ring, rx_ring->next_to_clean);
> + rx_buffer = i40e_rx_bi(rx_ring, rx_ring->next_to_process);
> rx_buffer->page_count =
> #if (PAGE_SIZE < 8192)
> page_count(rx_buffer->page);
> @@ -2375,16 +2377,16 @@ void i40e_finalize_xdp_rx(struct i40e_ring *rx_ring, unsigned int xdp_res)
> }
>
> /**
> - * i40e_inc_ntc: Advance the next_to_clean index
> + * i40e_inc_ntp: Advance the next_to_process index
> * @rx_ring: Rx ring
> **/
> -static void i40e_inc_ntc(struct i40e_ring *rx_ring)
> +static void i40e_inc_ntp(struct i40e_ring *rx_ring)
> {
> - u32 ntc = rx_ring->next_to_clean + 1;
> + u32 ntp = rx_ring->next_to_process + 1;
>
> - ntc = (ntc < rx_ring->count) ? ntc : 0;
> - rx_ring->next_to_clean = ntc;
> - prefetch(I40E_RX_DESC(rx_ring, ntc));
> + ntp = (ntp < rx_ring->count) ? ntp : 0;
> + rx_ring->next_to_process = ntp;
> + prefetch(I40E_RX_DESC(rx_ring, ntp));
> }
>
> /**
> @@ -2421,6 +2423,7 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget,
> xdp_prog = READ_ONCE(rx_ring->xdp_prog);
>
> while (likely(total_rx_packets < (unsigned int)budget)) {
> + u16 ntp = rx_ring->next_to_process;
u32
> struct i40e_rx_buffer *rx_buffer;
> union i40e_rx_desc *rx_desc;
> unsigned int size;
> @@ -2433,7 +2436,7 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget,
> cleaned_count = 0;
> }
>
> - rx_desc = I40E_RX_DESC(rx_ring, rx_ring->next_to_clean);
> + rx_desc = I40E_RX_DESC(rx_ring, ntp);
>
> /* status_error_len will always be zero for unused descriptors
> * because it's cleared in cleanup, and overlaps with hdr_addr
> @@ -2452,8 +2455,8 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget,
> i40e_clean_programming_status(rx_ring,
> rx_desc->raw.qword[0],
> qword);
> - rx_buffer = i40e_rx_bi(rx_ring, rx_ring->next_to_clean);
> - i40e_inc_ntc(rx_ring);
> + rx_buffer = i40e_rx_bi(rx_ring, ntp);
> + i40e_inc_ntp(rx_ring);
> i40e_reuse_rx_page(rx_ring, rx_buffer);
> cleaned_count++;
> continue;
> @@ -2509,7 +2512,8 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget,
> i40e_put_rx_buffer(rx_ring, rx_buffer);
> cleaned_count++;
>
> - i40e_inc_ntc(rx_ring);
> + i40e_inc_ntp(rx_ring);
> + rx_ring->next_to_clean = rx_ring->next_to_process;
> if (i40e_is_non_eop(rx_ring, rx_desc))
> continue;
>
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.h b/drivers/net/ethernet/intel/i40e/i40e_txrx.h
> index 3e2935365104..6e0fd73367df 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.h
> +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.h
> @@ -338,6 +338,10 @@ struct i40e_ring {
> u8 dcb_tc; /* Traffic class of ring */
> u8 __iomem *tail;
>
> + /* Next descriptor to be processed; next_to_clean is updated only on
> + * processing EOP descriptor
> + */
> + u16 next_to_process;
> /* high bit set means dynamic, use accessor routines to read/write.
> * hardware only supports 2us resolution for the ITR registers.
> * these values always store the USER setting, and must be converted
> --
> 2.34.1
>
