On Wed, Mar 22, 2023 at 10:43:19PM -0700, Ronak Doshi wrote:
> Currently, vmxnet3 uses GRO callback only if LRO is disabled. However,
> on smartNic based setups where UPT is supported, LRO can be enabled
> from guest VM but UPT devicve does not support LRO as of now. In such
> cases, there can be performance degradation as GRO is not being done.
>
> This patch fixes this issue by calling GRO API when UPT is enabled. We
> use updateRxProd to determine if UPT mode is active or not.
>
> To clarify few things discussed over the thread:
> The patch is not neglecting any feature bits nor disabling GRO. It uses
> GRO callback when UPT is active as LRO is not available in UPT.
> GRO callback cannot be used as default for all cases as it degrades
> performance for non-UPT cases or for cases when LRO is already done in
> ESXi.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 6f91f4ba046e ("vmxnet3: add support for capability registers")
> Signed-off-by: Ronak Doshi <doshir@xxxxxxxxxx>
> Acked-by: Guolin Yang <gyang@xxxxxxxxxx>
Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
> ---
> drivers/net/vmxnet3/vmxnet3_drv.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
> index 682987040ea8..8f7ac7d85afc 100644
> --- a/drivers/net/vmxnet3/vmxnet3_drv.c
> +++ b/drivers/net/vmxnet3/vmxnet3_drv.c
> @@ -1688,7 +1688,8 @@ vmxnet3_rq_rx_complete(struct vmxnet3_rx_queue *rq,
> if (unlikely(rcd->ts))
> __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), rcd->tci);
>
> - if (adapter->netdev->features & NETIF_F_LRO)
> + /* Use GRO callback if UPT is enabled */
> + if ((adapter->netdev->features & NETIF_F_LRO) && !rq->shared->updateRxProd)
nit: this could be two lines, fitting into 80 columns
> netif_receive_skb(skb);
> else
> napi_gro_receive(&rq->napi, skb);
> --
> 2.11.0
>
