Re: [PATCH net-next 2/3] igc: offload queue max SDU from tc-taprio

[Leon Romanovsky <leon@kernel.org>]

On Wed, Jan 25, 2023 at 01:27:01PM -0800, Tony Nguyen wrote:
> From: Tan Tee Min <tee.min.tan@linux.intel.com>
> 
> Add support for configuring the max SDU for each Tx queue.
> If not specified, keep the default.
> 
> All link speeds have been tested with this implementation.
> No performance issue observed.
> 
> How to test:
> 
> 1) Configure the tc with max-sdu
> 
> tc qdisc replace dev $IFACE parent root handle 100 taprio \
>     num_tc 4 \
>     map 0 1 2 3 3 3 3 3 3 3 3 3 3 3 3 3 \
>     queues 1@0 1@1 1@2 1@3 \
>     base-time $BASE \
>     sched-entry S 0xF 1000000 \
>     max-sdu 1500 1498 0 0 0 0 0 0 0 0 0 0 0 0 0 0 \
>     flags 0x2 \
>     txtime-delay 0
> 
> 2) Use network statistic to watch the tx queue packet to see if
> packet able to go out or drop.
> 
> Signed-off-by: Tan Tee Min <tee.min.tan@linux.intel.com>
> Signed-off-by: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>
> Tested-by: Naama Meir <naamax.meir@linux.intel.com>
> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
> ---
>  drivers/net/ethernet/intel/igc/igc.h      |  1 +
>  drivers/net/ethernet/intel/igc/igc_main.c | 44 +++++++++++++++++++++++
>  2 files changed, 45 insertions(+)

<...>

> +skb_drop:
> +	dev_kfree_skb_any(skb);
> +	skb = NULL;

Why do you set skb to be NULL?

> +
>  	return NETDEV_TX_OK;
>  }
>  

Thanks