Subject: Re: [PATCH net-next 5/5] ixgbe: xsk: add TX multi-buffer support

From: Maciej Fijalkowski <[email-masked]>
Date: Fri, 25 Jul 2025 12:00:12 +0200

On Sun, Jul 20, 2025 at 05:11:23PM +0800, Jason Xing wrote:
> From: Jason Xing <[email-masked]>
> 
> Use the common interface to see if the desc is the end of packets. If
> so, set IXGBE_TXD_CMD_EOP bit instead of setting for all preceding
> descriptors. This is also how i40e driver did in commit a92b96c4ae10
> ("i40e: xsk: add TX multi-buffer support").
> 
> Signed-off-by: Jason Xing <[email-masked]>
> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 4 ++++
>  drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c  | 4 +++-
>  2 files changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> index a59fd8f74b5e..c34737065f9e 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> @@ -52,6 +52,8 @@
>  #include "ixgbe_txrx_common.h"
>  #include "devlink/devlink.h"
>  
> +#define IXGBE_MAX_BUFFER_TXD 4
> +
>  char ixgbe_driver_name[] = "ixgbe";
>  static const char ixgbe_driver_string[] =
>  			      "Intel(R) 10 Gigabit PCI Express Network Driver";
> @@ -11805,6 +11807,8 @@ static int ixgbe_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>  	netdev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
>  			       NETDEV_XDP_ACT_XSK_ZEROCOPY;
>  
> +	netdev->xdp_zc_max_segs = IXGBE_MAX_BUFFER_TXD;

Hi Jason,

nack to this as you would allow fragmented frames on Rx side which is not
supported even with your patchset.

Generally ixgbe needs some love, i have several patches in my backlog plus
I think Larysa will be focusing on this driver.

please stick to enabling xsk batching on tx side.

> +
>  	/* MTU range: 68 - 9710 */
>  	netdev->min_mtu = ETH_MIN_MTU;
>  	netdev->max_mtu = IXGBE_MAX_JUMBO_FRAME_SIZE - (ETH_HLEN + ETH_FCS_LEN);
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
> index 9fe2c4bf8bc5..3d9fa4f2403e 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
> @@ -424,7 +424,9 @@ static void ixgbe_xmit_pkt(struct ixgbe_ring *xdp_ring, struct xdp_desc *desc,
>  	cmd_type = IXGBE_ADVTXD_DTYP_DATA |
>  		   IXGBE_ADVTXD_DCMD_DEXT |
>  		   IXGBE_ADVTXD_DCMD_IFCS;
> -	cmd_type |= desc[i].len | IXGBE_TXD_CMD_EOP;
> +	cmd_type |= desc[i].len;
> +	if (xsk_is_eop_desc(&desc[i]))
> +		cmd_type |= IXGBE_TXD_CMD_EOP;
>  	tx_desc->read.cmd_type_len = cpu_to_le32(cmd_type);
>  	tx_desc->read.olinfo_status =
>  		cpu_to_le32(desc[i].len << IXGBE_ADVTXD_PAYLEN_SHIFT);
> -- 
> 2.41.3
>