Re: [dpdk-dev] [PATCH v2 01/15] net/mlx5: support 16 hardware priorities

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

On Tue, Apr 10, 2018 at 09:34:01PM +0800, Xueming Li wrote:
> Adjust flow priority mapping to adapt new hardware 16 verb flow
> priorites support:
> 0-3: RTE FLOW tunnel rule
> 4-7: RTE FLOW non-tunnel rule
> 8-15: PMD control flow

This commit log is inducing people in error, this amount of priority
depends on the Mellanox OFED installed, it is not available on upstream
Linux kernel yet nor in the current Mellanox OFED GA.  

What happens when those amount of priority are not available, is it
removing a functionality?  Will it collide with other flows?

> Signed-off-by: Xueming Li <xuemingl@mellanox.com>
> ---
>  drivers/net/mlx5/mlx5.c         |  10 ++++
>  drivers/net/mlx5/mlx5.h         |   8 +++
>  drivers/net/mlx5/mlx5_flow.c    | 107 ++++++++++++++++++++++++++++++----------
>  drivers/net/mlx5/mlx5_trigger.c |   8 ---
>  4 files changed, 100 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5.c b/drivers/net/mlx5/mlx5.c
> index cfab55897..a1f2799e5 100644
> --- a/drivers/net/mlx5/mlx5.c
> +++ b/drivers/net/mlx5/mlx5.c
> @@ -197,6 +197,7 @@ mlx5_dev_close(struct rte_eth_dev *dev)
>  		priv->txqs_n = 0;
>  		priv->txqs = NULL;
>  	}
> +	mlx5_flow_delete_drop_queue(dev);
>
>  	if (priv->pd != NULL) {
>  		assert(priv->ctx != NULL);
>  		claim_zero(mlx5_glue->dealloc_pd(priv->pd));
> @@ -993,6 +994,15 @@ mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
>  		mlx5_set_link_up(eth_dev);
>  		/* Store device configuration on private structure. */
>  		priv->config = config;
> +		/* Create drop queue. */
> +		err = mlx5_flow_create_drop_queue(eth_dev);
> +		if (err) {
> +			DRV_LOG(ERR, "port %u drop queue allocation failed: %s",
> +				eth_dev->data->port_id, strerror(rte_errno));
> +			goto port_error;
> +		}
> +		/* Supported flow priority number detection. */
> +		mlx5_flow_priorities_detect(eth_dev);
>  		continue;
>  port_error:
>  		if (priv)
> diff --git a/drivers/net/mlx5/mlx5.h b/drivers/net/mlx5/mlx5.h
> index 63b24e6bb..708272f6d 100644
> --- a/drivers/net/mlx5/mlx5.h
> +++ b/drivers/net/mlx5/mlx5.h
> @@ -89,6 +89,8 @@ struct mlx5_dev_config {
>  	unsigned int rx_vec_en:1; /* Rx vector is enabled. */
>  	unsigned int mpw_hdr_dseg:1; /* Enable DSEGs in the title WQEBB. */
>  	unsigned int vf_nl_en:1; /* Enable Netlink requests in VF mode. */
> +	unsigned int flow_priority_shift; /* Non-tunnel flow priority shift. */
> +	unsigned int control_flow_priority; /* Control flow priority. */
>  	unsigned int tso_max_payload_sz; /* Maximum TCP payload for TSO. */
>  	unsigned int ind_table_max_size; /* Maximum indirection table size. */
>  	int txq_inline; /* Maximum packet size for inlining. */
> @@ -105,6 +107,11 @@ enum mlx5_verbs_alloc_type {
>  	MLX5_VERBS_ALLOC_TYPE_RX_QUEUE,
>  };
>  
> +/* 8 Verbs priorities per flow. */
> +#define MLX5_VERBS_FLOW_PRIO_8 8
> +/* 4 Verbs priorities per flow. */
> +#define MLX5_VERBS_FLOW_PRIO_4 4
> +
>  /**
>   * Verbs allocator needs a context to know in the callback which kind of
>   * resources it is allocating.
> @@ -253,6 +260,7 @@ int mlx5_traffic_restart(struct rte_eth_dev *dev);
>  
>  /* mlx5_flow.c */
>  
> +void mlx5_flow_priorities_detect(struct rte_eth_dev *dev);
>  int mlx5_flow_validate(struct rte_eth_dev *dev,
>  		       const struct rte_flow_attr *attr,
>  		       const struct rte_flow_item items[],
> diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
> index 288610620..394760418 100644
> --- a/drivers/net/mlx5/mlx5_flow.c
> +++ b/drivers/net/mlx5/mlx5_flow.c
> @@ -32,9 +32,6 @@
>  #include "mlx5_prm.h"
>  #include "mlx5_glue.h"
>  
> -/* Define minimal priority for control plane flows. */
> -#define MLX5_CTRL_FLOW_PRIORITY 4
> -
>  /* Internet Protocol versions. */
>  #define MLX5_IPV4 4
>  #define MLX5_IPV6 6
> @@ -129,7 +126,7 @@ const struct hash_rxq_init hash_rxq_init[] = {
>  				IBV_RX_HASH_SRC_PORT_TCP |
>  				IBV_RX_HASH_DST_PORT_TCP),
>  		.dpdk_rss_hf = ETH_RSS_NONFRAG_IPV4_TCP,
> -		.flow_priority = 1,
> +		.flow_priority = 0,
>  		.ip_version = MLX5_IPV4,
>  	},
>  	[HASH_RXQ_UDPV4] = {
> @@ -138,7 +135,7 @@ const struct hash_rxq_init hash_rxq_init[] = {
>  				IBV_RX_HASH_SRC_PORT_UDP |
>  				IBV_RX_HASH_DST_PORT_UDP),
>  		.dpdk_rss_hf = ETH_RSS_NONFRAG_IPV4_UDP,
> -		.flow_priority = 1,
> +		.flow_priority = 0,
>  		.ip_version = MLX5_IPV4,
>  	},
>  	[HASH_RXQ_IPV4] = {
> @@ -146,7 +143,7 @@ const struct hash_rxq_init hash_rxq_init[] = {
>  				IBV_RX_HASH_DST_IPV4),
>  		.dpdk_rss_hf = (ETH_RSS_IPV4 |
>  				ETH_RSS_FRAG_IPV4),
> -		.flow_priority = 2,
> +		.flow_priority = 1,
>  		.ip_version = MLX5_IPV4,
>  	},
>  	[HASH_RXQ_TCPV6] = {
> @@ -155,7 +152,7 @@ const struct hash_rxq_init hash_rxq_init[] = {
>  				IBV_RX_HASH_SRC_PORT_TCP |
>  				IBV_RX_HASH_DST_PORT_TCP),
>  		.dpdk_rss_hf = ETH_RSS_NONFRAG_IPV6_TCP,
> -		.flow_priority = 1,
> +		.flow_priority = 0,
>  		.ip_version = MLX5_IPV6,
>  	},
>  	[HASH_RXQ_UDPV6] = {
> @@ -164,7 +161,7 @@ const struct hash_rxq_init hash_rxq_init[] = {
>  				IBV_RX_HASH_SRC_PORT_UDP |
>  				IBV_RX_HASH_DST_PORT_UDP),
>  		.dpdk_rss_hf = ETH_RSS_NONFRAG_IPV6_UDP,
> -		.flow_priority = 1,
> +		.flow_priority = 0,
>  		.ip_version = MLX5_IPV6,
>  	},
>  	[HASH_RXQ_IPV6] = {
> @@ -172,13 +169,13 @@ const struct hash_rxq_init hash_rxq_init[] = {
>  				IBV_RX_HASH_DST_IPV6),
>  		.dpdk_rss_hf = (ETH_RSS_IPV6 |
>  				ETH_RSS_FRAG_IPV6),
> -		.flow_priority = 2,
> +		.flow_priority = 1,
>  		.ip_version = MLX5_IPV6,
>  	},
>  	[HASH_RXQ_ETH] = {
>  		.hash_fields = 0,
>  		.dpdk_rss_hf = 0,
> -		.flow_priority = 3,
> +		.flow_priority = 2,
>  	},
>  };

If the amount of priorities remains 8, you are removing the priority for
the tunnel flows introduced by 
commit 749365717f5c ("net/mlx5: change tunnel flow priority")

Please keep this functionality when this patch fails to get the expected
16 Verbs priorities.

> @@ -536,6 +533,8 @@ mlx5_flow_item_validate(const struct rte_flow_item *item,
>  /**
>   * Extract attribute to the parser.
>   *
> + * @param dev
> + *   Pointer to Ethernet device.
>   * @param[in] attr
>   *   Flow rule attributes.
>   * @param[out] error
> @@ -545,9 +544,12 @@ mlx5_flow_item_validate(const struct rte_flow_item *item,
>   *   0 on success, a negative errno value otherwise and rte_errno is set.
>   */
>  static int
> -mlx5_flow_convert_attributes(const struct rte_flow_attr *attr,
> +mlx5_flow_convert_attributes(struct rte_eth_dev *dev,
> +			     const struct rte_flow_attr *attr,
>  			     struct rte_flow_error *error)
>  {
> +	struct priv *priv = dev->data->dev_private;
> +
>  	if (attr->group) {
>  		rte_flow_error_set(error, ENOTSUP,
>  				   RTE_FLOW_ERROR_TYPE_ATTR_GROUP,
> @@ -555,7 +557,7 @@ mlx5_flow_convert_attributes(const struct rte_flow_attr *attr,
>  				   "groups are not supported");
>  		return -rte_errno;
>  	}
> -	if (attr->priority && attr->priority != MLX5_CTRL_FLOW_PRIORITY) {
> +	if (attr->priority > priv->config.control_flow_priority) {
>  		rte_flow_error_set(error, ENOTSUP,
>  				   RTE_FLOW_ERROR_TYPE_ATTR_PRIORITY,
>  				   NULL,
> @@ -900,30 +902,38 @@ mlx5_flow_convert_allocate(unsigned int size, struct rte_flow_error *error)
>   * Make inner packet matching with an higher priority from the non Inner
>   * matching.
>   *
> + * @param dev
> + *   Pointer to Ethernet device.
>   * @param[in, out] parser
>   *   Internal parser structure.
>   * @param attr
>   *   User flow attribute.
>   */
>  static void
> -mlx5_flow_update_priority(struct mlx5_flow_parse *parser,
> +mlx5_flow_update_priority(struct rte_eth_dev *dev,
> +			  struct mlx5_flow_parse *parser,
>  			  const struct rte_flow_attr *attr)
>  {
> +	struct priv *priv = dev->data->dev_private;
>  	unsigned int i;
> +	uint16_t priority;
>  
> +	if (priv->config.flow_priority_shift == 1)
> +		priority = attr->priority * MLX5_VERBS_FLOW_PRIO_4;
> +	else
> +		priority = attr->priority * MLX5_VERBS_FLOW_PRIO_8;
> +	if (!parser->inner)
> +		priority += priv->config.flow_priority_shift;
>  	if (parser->drop) {
> -		parser->queue[HASH_RXQ_ETH].ibv_attr->priority =
> -			attr->priority +
> -			hash_rxq_init[HASH_RXQ_ETH].flow_priority;
> +		parser->queue[HASH_RXQ_ETH].ibv_attr->priority = priority +
> +				hash_rxq_init[HASH_RXQ_ETH].flow_priority;
>  		return;
>  	}
>  	for (i = 0; i != hash_rxq_init_n; ++i) {
> -		if (parser->queue[i].ibv_attr) {
> -			parser->queue[i].ibv_attr->priority =
> -				attr->priority +
> -				hash_rxq_init[i].flow_priority -
> -				(parser->inner ? 1 : 0);
> -		}
> +		if (!parser->queue[i].ibv_attr)
> +			continue;
> +		parser->queue[i].ibv_attr->priority = priority +
> +				hash_rxq_init[i].flow_priority;
>  	}
>  }
>  
> @@ -1087,7 +1097,7 @@ mlx5_flow_convert(struct rte_eth_dev *dev,
>  		.layer = HASH_RXQ_ETH,
>  		.mark_id = MLX5_FLOW_MARK_DEFAULT,
>  	};
> -	ret = mlx5_flow_convert_attributes(attr, error);
> +	ret = mlx5_flow_convert_attributes(dev, attr, error);
>  	if (ret)
>  		return ret;
>  	ret = mlx5_flow_convert_actions(dev, actions, error, parser);
> @@ -1158,7 +1168,7 @@ mlx5_flow_convert(struct rte_eth_dev *dev,
>  	 */
>  	if (!parser->drop)
>  		mlx5_flow_convert_finalise(parser);
> -	mlx5_flow_update_priority(parser, attr);
> +	mlx5_flow_update_priority(dev, parser, attr);
>  exit_free:
>  	/* Only verification is expected, all resources should be released. */
>  	if (!parser->create) {
> @@ -2450,7 +2460,7 @@ mlx5_ctrl_flow_vlan(struct rte_eth_dev *dev,
>  	struct priv *priv = dev->data->dev_private;
>  	const struct rte_flow_attr attr = {
>  		.ingress = 1,
> -		.priority = MLX5_CTRL_FLOW_PRIORITY,
> +		.priority = priv->config.control_flow_priority,
>  	};
>  	struct rte_flow_item items[] = {
>  		{
> @@ -3161,3 +3171,50 @@ mlx5_dev_filter_ctrl(struct rte_eth_dev *dev,
>  	}
>  	return 0;
>  }
> +
> +/**
> + * Detect number of Verbs flow priorities supported.
> + *
> + * @param dev
> + *   Pointer to Ethernet device.
> + */
> +void
> +mlx5_flow_priorities_detect(struct rte_eth_dev *dev)
> +{
> +	struct priv *priv = dev->data->dev_private;
> +	uint32_t verb_priorities = MLX5_VERBS_FLOW_PRIO_8 * 2;
> +	struct {
> +		struct ibv_flow_attr attr;
> +		struct ibv_flow_spec_eth eth;
> +		struct ibv_flow_spec_action_drop drop;
> +	} flow_attr = {
> +		.attr = {
> +			.num_of_specs = 2,
> +			.priority = verb_priorities - 1,
> +		},
> +		.eth = {
> +			.type = IBV_FLOW_SPEC_ETH,
> +			.size = sizeof(struct ibv_flow_spec_eth),
> +		},
> +		.drop = {
> +			.size = sizeof(struct ibv_flow_spec_action_drop),
> +			.type = IBV_FLOW_SPEC_ACTION_DROP,
> +		},
> +	};
> +	struct ibv_flow *flow;
> +
> +	if (priv->config.control_flow_priority)
> +		return;
> +	flow = mlx5_glue->create_flow(priv->flow_drop_queue->qp,
> +				      &flow_attr.attr);
> +	if (flow) {
> +		priv->config.flow_priority_shift = MLX5_VERBS_FLOW_PRIO_8 / 2;
> +		claim_zero(mlx5_glue->destroy_flow(flow));
> +	} else {
> +		priv->config.flow_priority_shift = 1;
> +		verb_priorities = verb_priorities / 2;
> +	}
> +	priv->config.control_flow_priority = 1;
> +	DRV_LOG(INFO, "port %u Verbs flow priorities: %d",
> +		dev->data->port_id, verb_priorities);
> +}
> diff --git a/drivers/net/mlx5/mlx5_trigger.c b/drivers/net/mlx5/mlx5_trigger.c
> index 6bb4ffb14..d80a2e688 100644
> --- a/drivers/net/mlx5/mlx5_trigger.c
> +++ b/drivers/net/mlx5/mlx5_trigger.c
> @@ -148,12 +148,6 @@ mlx5_dev_start(struct rte_eth_dev *dev)
>  	int ret;
>  
>  	dev->data->dev_started = 1;
> -	ret = mlx5_flow_create_drop_queue(dev);
> -	if (ret) {
> -		DRV_LOG(ERR, "port %u drop queue allocation failed: %s",
> -			dev->data->port_id, strerror(rte_errno));
> -		goto error;
> -	}
>  	DRV_LOG(DEBUG, "port %u allocating and configuring hash Rx queues",
>  		dev->data->port_id);
>  	rte_mempool_walk(mlx5_mp2mr_iter, priv);
> @@ -202,7 +196,6 @@ mlx5_dev_start(struct rte_eth_dev *dev)
>  	mlx5_traffic_disable(dev);
>  	mlx5_txq_stop(dev);
>  	mlx5_rxq_stop(dev);
> -	mlx5_flow_delete_drop_queue(dev);
>  	rte_errno = ret; /* Restore rte_errno. */
>  	return -rte_errno;
>  }
> @@ -237,7 +230,6 @@ mlx5_dev_stop(struct rte_eth_dev *dev)
>  	mlx5_rxq_stop(dev);
>  	for (mr = LIST_FIRST(&priv->mr); mr; mr = LIST_FIRST(&priv->mr))
>  		mlx5_mr_release(mr);
> -	mlx5_flow_delete_drop_queue(dev);
>  }
>  
>  /**
> -- 
> 2.13.3

I have few concerns on this, mlx5_pci_probe() will also probe any
under layer verbs device, and in a near future the representors
associated to a VF.
Making such detection should only be done once by the PF, I also wander
if it is possible to make such drop action in a representor directly
using Verbs.

Another concern is, this patch will be reverted in some time when those
16 priority will be always available.  It will be easier to remove this
detection function than searching for all those modifications.

I would suggest to have a standalone mlx5_flow_priorities_detect() which
creates and deletes all resources needed for this detection.

Thanks,

-- 
Nélio Laranjeiro
6WIND