Re: [RFC v0 1/1] dmadev: provide priority configuration support

[fengchengwen <fengchengwen@huawei.com>]

On 2024/9/13 20:10, Vamsi Krishna wrote:
> From: Vamsi Attunuru <vattunuru@marvell.com>
> 
> Some DMA controllers offer the ability to configure priority level
> for the hardware command queues, allowing for the prioritization of
> DMA command execution based on queue importance.
> 
> This patch introduces the necessary fields in the dmadev structures to
> retrieve information about the hardware-supported priority levels and to
> enable priority configuration from the application.
> 
> Signed-off-by: Vamsi Attunuru <vattunuru@marvell.com>
> Signed-off-by: Amit Prakash Shukla <amitprakashs@marvell.com>
> ---
> 
> Deprecation notice:
> https://patches.dpdk.org/project/dpdk/patch/20240730144612.2132848-1-amitprakashs@marvell.com/
> 
> * Assuming we do not anticipate any advanced scheduling schemes for dmadev queues,
>   this RFC is intended to support a strict prioirty scheme.
> 
>  doc/guides/rel_notes/release_24_11.rst | 15 +++------------
>  lib/dmadev/rte_dmadev.c                | 10 ++++++++++
>  lib/dmadev/rte_dmadev.h                | 11 +++++++++++
>  3 files changed, 24 insertions(+), 12 deletions(-)
> 
> diff --git a/doc/guides/rel_notes/release_24_11.rst b/doc/guides/rel_notes/release_24_11.rst
> index 0ff70d9057..dc711bbf98 100644
> --- a/doc/guides/rel_notes/release_24_11.rst
> +++ b/doc/guides/rel_notes/release_24_11.rst
> @@ -88,18 +88,9 @@ API Changes
>  ABI Changes
>  -----------
>  
> -.. This section should contain ABI changes. Sample format:
> -
> -   * sample: Add a short 1-2 sentence description of the ABI change
> -     which was announced in the previous releases and made in this release.
> -     Start with a scope label like "ethdev:".
> -     Use fixed width quotes for ``function_names`` or ``struct_names``.
> -     Use the past tense.
> -
> -   This section is a comment. Do not overwrite or remove it.
> -   Also, make sure to start the actual text at the margin.
> -   =======================================================
> -
> +* dmadev: Added ``nb_priorities`` field to ``rte_dma_info`` structure and
> +  ``priority`` field to ``rte_dma_conf`` structure to get device supported
> +  priority levels and configure required priority from the application.
>  
>  Known Issues
>  ------------
> diff --git a/lib/dmadev/rte_dmadev.c b/lib/dmadev/rte_dmadev.c
> index 845727210f..053170f55a 100644
> --- a/lib/dmadev/rte_dmadev.c
> +++ b/lib/dmadev/rte_dmadev.c
> @@ -497,6 +497,16 @@ rte_dma_configure(int16_t dev_id, const struct rte_dma_conf *dev_conf)
>  		return -EINVAL;
>  	}
>  
> +	if (dev_info.nb_priorities == 1) {
> +		RTE_DMA_LOG(ERR, "Device %d must support more than 1 priority, or else 0", dev_id);
> +		return -EINVAL;
> +	}
> +
> +	if (dev_info.nb_priorities && (dev_conf->priority >= dev_info.nb_priorities)) {
> +		RTE_DMA_LOG(ERR, "Device %d configure invalid priority", dev_id);
> +		return -EINVAL;
> +	}

Please add trace support

> +
>  	if (*dev->dev_ops->dev_configure == NULL)
>  		return -ENOTSUP;
>  	ret = (*dev->dev_ops->dev_configure)(dev, dev_conf,
> diff --git a/lib/dmadev/rte_dmadev.h b/lib/dmadev/rte_dmadev.h
> index 5474a5281d..d59fcf1b61 100644
> --- a/lib/dmadev/rte_dmadev.h
> +++ b/lib/dmadev/rte_dmadev.h
> @@ -297,6 +297,10 @@ struct rte_dma_info {
>  	int16_t numa_node;
>  	/** Number of virtual DMA channel configured. */
>  	uint16_t nb_vchans;
> +	/** Number of priority levels (must be > 1), if supported by DMA HW channel.
> +	 * 0 otherwise.
> +	 */
> +	uint16_t nb_priorities;

Suggest add priority schedule policy capability, for example:
RTE_DMA_CAPA_PRIORITY_POLICY_SP

>  };
>  
>  /**
> @@ -332,6 +336,13 @@ struct rte_dma_conf {
>  	 * @see RTE_DMA_CAPA_SILENT
>  	 */
>  	bool enable_silent;
> +	/* The prioirty of the DMA HW channel.
> +	 * This value cannot be greater than or equal to the field 'nb_priorities'
> +	 * of struct rte_dma_info which get from rte_dma_info_get().
> +	 * Among the values between '0' and 'nb_priorities - 1', lowest value
> +	 * indicates higher priority and vice-versa.
> +	 */
> +	uint16_t priority;
>  };
>  
>  /**