[Intel-wired-lan] [PATCH intel-next v6 2/8] i40e: change Rx buffer size for legacy-rx to support XDP multi-buffer

[Rout, ChandanX]

>-----Original Message-----
>From: Intel-wired-lan <intel-wired-lan-bounces at osuosl.org> On Behalf Of
>Sarkar, Tirthendu
>Sent: 18 February 2023 00:45
>To: intel-wired-lan at lists.osuosl.org
>Cc: Sarkar, Tirthendu <tirthendu.sarkar at intel.com>; netdev at vger.kernel.org;
>Brandeburg, Jesse <jesse.brandeburg at intel.com>; Nguyen, Anthony L
><anthony.l.nguyen at intel.com>; bpf at vger.kernel.org; Karlsson, Magnus
><magnus.karlsson at intel.com>
>Subject: [Intel-wired-lan] [PATCH intel-next v6 2/8] i40e: change Rx buffer size
>for legacy-rx to support XDP multi-buffer
>
>Adding support for XDP multi-buffer entails adding information of all the
>fragments of the packet in the xdp_buff. This approach implies that
>underlying buffer has to provide tailroom for skb_shared_info.
>
>In the legacy-rx mode, driver can only configure upto 2k sized Rx buffers and
>with the current configuration of 2k sized Rx buffers there is no way to do
>tailroom reservation for skb_shared_info. Hence size of Rx buffers is now
>lowered to 1664 (2k - sizeof(skb_shared_info)). Also, driver can only chain
>upto 5 Rx buffers and this means max MTU supported for legacy-rx is now
>8320.
>
>Signed-off-by: Tirthendu Sarkar <tirthendu.sarkar at intel.com>
>---
> drivers/net/ethernet/intel/i40e/i40e_main.c | 2 +-
>drivers/net/ethernet/intel/i40e/i40e_txrx.h | 1 +
> 2 files changed, 2 insertions(+), 1 deletion(-)
>

Tested-by: Chandan Kumar Rout <chandanx.rout at intel.com> (A Contingent Worker at Intel)