Re: [PATCH] net/mlx5: implement drop action in hardware classifier

["Nélio Laranjeiro" <nelio.laranjeiro@6wind.com>]

On Sun, May 28, 2017 at 06:49:20AM +0000, Shachar Beiser wrote:
> The current drop action is implemented as a queue tail drop,
> requiring to instantiate multiple WQs to maintain high drop rate.
> This commit, implements the drop action in hardware classifier.
> This enables to reduce the amount of contexts needed for the drop,
> without affecting the drop rate.
> 
> Signed-off-by: Shachar Beiser <shacharbe@mellanox.com>
> ---
>  drivers/net/mlx5/Makefile    |  5 +++++
>  drivers/net/mlx5/mlx5_flow.c | 43 +++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 48 insertions(+)
> 
> diff --git a/drivers/net/mlx5/Makefile b/drivers/net/mlx5/Makefile
> index c079959..daf8013 100644
> --- a/drivers/net/mlx5/Makefile
> +++ b/drivers/net/mlx5/Makefile
> @@ -101,6 +101,11 @@ mlx5_autoconf.h.new: FORCE
>  mlx5_autoconf.h.new: $(RTE_SDK)/buildtools/auto-config-h.sh
>  	$Q $(RM) -f -- '$@'
>  	$Q sh -- '$<' '$@' \
> +		HAVE_VERBS_IBV_EXP_FLOW_SPEC_ACTION_DROP \
> +		infiniband/verbs_exp.h \
> +		enum IBV_EXP_FLOW_SPEC_ACTION_DROP \
> +		$(AUTOCONF_OUTPUT)
> +	$Q sh -- '$<' '$@' \
>  		HAVE_VERBS_IBV_EXP_CQ_COMPRESSED_CQE \
>  		infiniband/verbs_exp.h \
>  		enum IBV_EXP_CQ_COMPRESSED_CQE \
> diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
> index adcbe3f..e243d39 100644
> --- a/drivers/net/mlx5/mlx5_flow.c
> +++ b/drivers/net/mlx5/mlx5_flow.c
> @@ -994,6 +994,11 @@ struct mlx5_flow_action {
>  {
>  	struct rte_flow *rte_flow;
>  
> +#ifdef HAVE_VERBS_IBV_EXP_FLOW_SPEC_ACTION_DROP
> +	struct ibv_exp_flow_spec_action_drop *drop;
> +	unsigned int size = sizeof(struct ibv_exp_flow_spec_action_drop);
> +#endif

Extra empty line before the #ifdef

> +
>  	assert(priv->pd);
>  	assert(priv->ctx);
>  	rte_flow = rte_calloc(__func__, 1, sizeof(*rte_flow), 0);
> @@ -1007,6 +1012,15 @@ struct mlx5_flow_action {
>  	rte_flow->qp = priv->flow_drop_queue->qp;
>  	if (!priv->started)
>  		return rte_flow;
> +#ifdef HAVE_VERBS_IBV_EXP_FLOW_SPEC_ACTION_DROP
> +	drop = (void *)((uintptr_t)flow->ibv_attr + flow->offset);
> +	*drop = (struct ibv_exp_flow_spec_action_drop){
> +			.type = IBV_EXP_FLOW_SPEC_ACTION_DROP,
> +			.size = size,
> +	};
> +	++flow->ibv_attr->num_of_specs;
> +	flow->offset += sizeof(struct ibv_exp_flow_spec_action_drop);
> +#endif
>  	rte_flow->ibv_flow = ibv_exp_create_flow(rte_flow->qp,
>  						 rte_flow->ibv_attr);
>  	if (!rte_flow->ibv_flow) {
>[...]

>From what I see by just changing the value of MLX5_DROP_WQ_N when
HAVE_VERBS_IBV_EXP_FLOW_SPEC_ACTION_DROP (in the same source file)
limits the patch to this point.

Am I missing something?

Regards,

-- 
Nélio Laranjeiro
6WIND