Re: [dpdk-dev] [PATCH v5 5/8] mempool: get the mempool capability

[Olivier MATZ <olivier.matz@6wind.com>]

On Wed, Sep 06, 2017 at 04:58:31PM +0530, Santosh Shukla wrote:
> Allow mempool driver to advertise his pool capability.
> For that pupose, an api(rte_mempool_ops_get_capabilities)

typo: pupose -> purpose

> ...
> --- a/lib/librte_mempool/rte_mempool.c
> +++ b/lib/librte_mempool/rte_mempool.c
> @@ -528,6 +528,12 @@ rte_mempool_populate_default(struct rte_mempool *mp)
>  	if (mp->nb_mem_chunks != 0)
>  		return -EEXIST;
>  
> +	/* Get mempool capability */

capability -> capabilities

> +	ret = rte_mempool_ops_get_capabilities(mp, &mp->flags);
> +	if (ret < 0)
> +		RTE_LOG(DEBUG, MEMPOOL, "get_capability not supported for %s\n",
> +					mp->name);
> +

I think the error can be ignored only if it's -ENOTSUP.
Else, the error should be propagated.


> --- a/lib/librte_mempool/rte_mempool.h
> +++ b/lib/librte_mempool/rte_mempool.h
> @@ -389,6 +389,12 @@ typedef int (*rte_mempool_dequeue_t)(struct rte_mempool *mp,
>   */
>  typedef unsigned (*rte_mempool_get_count)(const struct rte_mempool *mp);
>  
> +/**
> + * Get the mempool capability.
> + */

capability -> capabilities

> +typedef int (*rte_mempool_get_capabilities_t)(const struct rte_mempool *mp,
> +		unsigned int *flags);
> +
>  /** Structure defining mempool operations structure */
>  struct rte_mempool_ops {
>  	char name[RTE_MEMPOOL_OPS_NAMESIZE]; /**< Name of mempool ops struct. */
> @@ -397,6 +403,10 @@ struct rte_mempool_ops {
>  	rte_mempool_enqueue_t enqueue;   /**< Enqueue an object. */
>  	rte_mempool_dequeue_t dequeue;   /**< Dequeue an object. */
>  	rte_mempool_get_count get_count; /**< Get qty of available objs. */
> +	/**
> +	 * Get the pool capability
> +	 */
> +	rte_mempool_get_capabilities_t get_capabilities;

capability -> capabilities


>  } __rte_cache_aligned;
>  
>  #define RTE_MEMPOOL_MAX_OPS_IDX 16  /**< Max registered ops structs */
> @@ -509,6 +519,22 @@ unsigned
>  rte_mempool_ops_get_count(const struct rte_mempool *mp);
>  
>  /**
> + * @internal wrapper for mempool_ops get_capabilities callback.
> + *
> + * @param mp [in]
> + *   Pointer to the memory pool.
> + * @param flags [out]
> + *   Pointer to the mempool flag.
> + * @return
> + *   - 0: Success; mempool driver has advetised his pool capability by Oring to
> + *   flags param.
> + *   - <0: Error; code of capability function.
> + */
> +int
> +rte_mempool_ops_get_capabilities(const struct rte_mempool *mp,
> +					unsigned int *flags);
> +
> +/**

The API is correct, but the flags should simply be returned, not or-ed.
I think it should be kept as simple as possible: a function called
get_somthing() is expected to return it without doing anything else.
Sorry if I wasn't clear in my previous message.

If there is a need to do a OR with mp->flags, it has to be done in the caller,
i.e. rte_mempool_populate_default().