[dpdk-dev] [RFC PATCH 1/2] ethdev: add function to adjust number of descriptors

[Andrew Rybchenko]

Hi,

On 04/24/2017 06:13 PM, Thomas Monjalon wrote:
> Hi,
>
> 02/03/2017 14:05, Andrew Rybchenko:
>> From: Roman Zhukov <Roman.Zhukov at oktetlabs.ru>
>>
>> Check that numbers of Rx and Tx descriptors satisfy descriptors limits
>> from the Ethernet device information, otherwise adjust them to boundaries.
>>
>> Signed-off-by: Roman Zhukov <Roman.Zhukov at oktetlabs.ru>
>> Signed-off-by: Andrew Rybchenko <arybchenko at solarflare.com>
> I think this helper is OK.
> We could add it in 17.08.

Thanks, we'll prepare patch series which updates alll example 
applications to use the helper.

Andrew.

> Is there any comment from PMD maintainers?
>
> [...]
>> +static void
>> +rte_eth_dev_adjust_nb_desc(uint16_t *nb_desc,
>> +			   const struct rte_eth_desc_lim *desc_lim)
>> +{
>> +	if (desc_lim->nb_align != 0)
>> +		*nb_desc = RTE_ALIGN_CEIL(*nb_desc, desc_lim->nb_align);
>> +
>> +	if (desc_lim->nb_max != 0)
>> +		*nb_desc = RTE_MIN(*nb_desc, desc_lim->nb_max);
>> +
>> +	*nb_desc = RTE_MAX(*nb_desc, desc_lim->nb_min);
>> +}
>> +
>> +int
>> +rte_eth_dev_adjust_nb_rx_tx_desc(uint8_t port_id,
>> +				 uint16_t *nb_rx_desc,
>> +				 uint16_t *nb_tx_desc)
>> +{
>> +	struct rte_eth_dev *dev;
>> +	struct rte_eth_dev_info dev_info;
>> +
>> +	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
>> +
>> +	dev = &rte_eth_devices[port_id];
>> +	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_infos_get, -ENOTSUP);
>> +
>> +	rte_eth_dev_info_get(port_id, &dev_info);
>> +
>> +	if (nb_rx_desc != NULL)
>> +		rte_eth_dev_adjust_nb_desc(nb_rx_desc, &dev_info.rx_desc_lim);
>> +
>> +	if (nb_tx_desc != NULL)
>> +		rte_eth_dev_adjust_nb_desc(nb_tx_desc, &dev_info.tx_desc_lim);
>> +
>> +	return 0;
>> +}
> [...]
>> +/**
>> + * Check that numbers of Rx and Tx descriptors satisfy descriptors limits from
>> + * the ethernet device information, otherwise adjust them to boundaries.
>> + *
>> + * @param port_id
>> + *   The port identifier of the Ethernet device.
>> + * @param nb_rx_desc
>> + *   A pointer to a uint16_t where the number of receive
>> + *   descriptors stored.
>> + * @param nb_tx_desc
>> + *   A pointer to a uint16_t where the number of transmit
>> + *   descriptors stored.
>> + * @return
>> + *   - (0) if successful.
>> + *   - (-ENOTSUP, -ENODEV or -EINVAL) on failure.
>> + */
>> +int rte_eth_dev_adjust_nb_rx_tx_desc(uint8_t port_id,
>> +				     uint16_t *nb_rx_desc,
>> +				     uint16_t *nb_tx_desc);
>> +