[v5,1/3] ethdev: introduce maximum Rx buffer size

  The "min_rx_bufsize" in struct rte_eth_dev_info stands for the minimum
Rx buffer size supported by hardware. Actually, some engines also have
the maximum Rx buffer specification, like, hns3, i40e and so on. If mbuf
data room size in mempool is greater then the maximum Rx buffer size
per descriptor supported by HW, the data size application used in each
mbuf is just as much as the maximum Rx buffer size instead of the whole
data room size.

So introduce maximum Rx buffer size which is not enforced just to
report user to avoid memory waste. In addition, fix the comment for
the "min_rx_bufsize" to make it be more specific.

Signed-off-by: Huisong Li <lihuisong@huawei.com>
Acked-by: Chengwen Feng <fengchengwen@huawei.com>
Acked-by: Morten Brørup <mb@smartsharesystems.com>
---
 doc/guides/rel_notes/release_23_11.rst |  7 +++++++
 lib/ethdev/rte_ethdev.c                |  8 ++++++++
 lib/ethdev/rte_ethdev.h                | 10 +++++++++-
 3 files changed, 24 insertions(+), 1 deletion(-)
  

Hi,

(minor notes below)

On Fri, 3 Nov 2023, Huisong Li wrote:

> The "min_rx_bufsize" in struct rte_eth_dev_info stands for the minimum
> Rx buffer size supported by hardware. Actually, some engines also have
> the maximum Rx buffer specification, like, hns3, i40e and so on. If mbuf
> data room size in mempool is greater then the maximum Rx buffer size
> per descriptor supported by HW, the data size application used in each
> mbuf is just as much as the maximum Rx buffer size instead of the whole
> data room size.
>
> So introduce maximum Rx buffer size which is not enforced just to
> report user to avoid memory waste. In addition, fix the comment for
> the "min_rx_bufsize" to make it be more specific.

Consider:
So introduce maximum Rx buffer size. It does not enforce anything;
its sole purpose is to inform the user of possible memory waste.

>
> Signed-off-by: Huisong Li <lihuisong@huawei.com>
> Acked-by: Chengwen Feng <fengchengwen@huawei.com>
> Acked-by: Morten Brørup <mb@smartsharesystems.com>
> ---
> doc/guides/rel_notes/release_23_11.rst |  7 +++++++
> lib/ethdev/rte_ethdev.c                |  8 ++++++++
> lib/ethdev/rte_ethdev.h                | 10 +++++++++-
> 3 files changed, 24 insertions(+), 1 deletion(-)
>
> diff --git a/doc/guides/rel_notes/release_23_11.rst b/doc/guides/rel_notes/release_23_11.rst
> index 95db98d098..d4f7d5b266 100644
> --- a/doc/guides/rel_notes/release_23_11.rst
> +++ b/doc/guides/rel_notes/release_23_11.rst
> @@ -122,6 +122,13 @@ New Features
>   a group's miss actions, which are the actions to be performed on packets
>   that didn't match any of the flow rules in the group.
>
> +* **Added maximum Rx buffer size to report.**

Consider: Added maximum Rx buffer size reporting.

> +
> +  Introduced the ``max_rx_bufsize`` field representing the maximum Rx
> +  buffer size per descriptor supported by HW in structure ``rte_eth_dev_info``
> +  to report user and to avoid wasting space of mempool.
> +  Its value is UINT32_MAX if driver doesn't report it.
> +
> * **Updated Amazon ena (Elastic Network Adapter) net driver.**
>
>   * Upgraded ENA HAL to latest version.
> diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
> index af23ac0ad0..24b708f772 100644
> --- a/lib/ethdev/rte_ethdev.c
> +++ b/lib/ethdev/rte_ethdev.c
> @@ -2112,6 +2112,7 @@ rte_eth_rx_queue_setup(uint16_t port_id, uint16_t rx_queue_id,
> 	struct rte_eth_dev *dev;
> 	struct rte_eth_dev_info dev_info;
> 	struct rte_eth_rxconf local_conf;
> +	uint32_t buf_data_size;
>
> 	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
> 	dev = &rte_eth_devices[port_id];
> @@ -2158,6 +2159,12 @@ rte_eth_rx_queue_setup(uint16_t port_id, uint16_t rx_queue_id,
> 			return ret;
>
> 		mbp_buf_size = rte_pktmbuf_data_room_size(mp);
> +		buf_data_size = mbp_buf_size - RTE_PKTMBUF_HEADROOM;
> +		if (buf_data_size > dev_info.max_rx_bufsize)
> +			RTE_ETHDEV_LOG(DEBUG,
> +				"For port_id=%u, the mbuf data buffer size (%u) is bigger than "

Consider: is larger than

> +				"max buffer size (%u) device can utilize, so mbuf size can be reduced.\n",
> +				port_id, buf_data_size, dev_info.max_rx_bufsize);
> 	} else if (rx_conf != NULL && rx_conf->rx_nseg > 0) {
> 		const struct rte_eth_rxseg_split *rx_seg;
> 		uint16_t n_seg;
> @@ -3757,6 +3764,7 @@ rte_eth_dev_info_get(uint16_t port_id, struct rte_eth_dev_info *dev_info)
> 	dev_info->min_mtu = RTE_ETHER_MIN_LEN - RTE_ETHER_HDR_LEN -
> 		RTE_ETHER_CRC_LEN;
> 	dev_info->max_mtu = UINT16_MAX;
> +	dev_info->max_rx_bufsize = UINT32_MAX;
>
> 	if (*dev->dev_ops->dev_infos_get == NULL)
> 		return -ENOTSUP;
> diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h
> index a53dd5a1ef..7133b73d26 100644
> --- a/lib/ethdev/rte_ethdev.h
> +++ b/lib/ethdev/rte_ethdev.h
> @@ -1723,7 +1723,15 @@ struct rte_eth_dev_info {
> 	uint16_t min_mtu;	/**< Minimum MTU allowed */
> 	uint16_t max_mtu;	/**< Maximum MTU allowed */
> 	const uint32_t *dev_flags; /**< Device flags */
> -	uint32_t min_rx_bufsize; /**< Minimum size of Rx buffer. */
> +	/** Minimum Rx buffer size per descriptor supported by HW. */
> +	uint32_t min_rx_bufsize;
> +	/**
> +	 * Maximum Rx buffer size per descriptor supported by HW.
> +	 * The value is not enforced, information only to application to
> +	 * optimize mbuf size. Its value is UINT32_MAX when not specified
> +	 * by the driver.

Consider: The value is not enforced. It's a hint for the application
to optimise mbuf size on mempool allocation. If the driver does not
restrict the maximum buffer size, reported value will be UINT32_MAX.

> +	 */
> +	uint32_t max_rx_bufsize;
> 	uint32_t max_rx_pktlen; /**< Maximum configurable length of Rx pkt. */
> 	/** Maximum configurable size of LRO aggregated packet. */
> 	uint32_t max_lro_pkt_size;
> -- 
> 2.33.0
>
>
Other than that,

Acked-by: Ivan Malov <ivan.malov@arknetworks.am>

Thank you.