[dpdk-dev] [PATCH v1 3/3] hash: add new API function to query the key count

[De Lara Guarch, Pablo]

> -----Original Message-----
> From: Wang, Yipeng1
> Sent: Friday, June 8, 2018 11:51 AM
> To: De Lara Guarch, Pablo <pablo.de.lara.guarch at intel.com>
> Cc: dev at dpdk.org; Wang, Yipeng1 <yipeng1.wang at intel.com>; Mcnamara,
> John <john.mcnamara at intel.com>; Richardson, Bruce
> <bruce.richardson at intel.com>; honnappa.nagarahalli at arm.com;
> vguvva at caviumnetworks.com; brijesh.s.singh at gmail.com
> Subject: [PATCH v1 3/3] hash: add new API function to query the key count
> 
> Add a new function, rte_hash_count, to return the number of keys that are
> currently stored in the hash table. Corresponding test functions are added into
> hash_test and hash_multiwriter test.
> 
> Signed-off-by: Yipeng Wang <yipeng1.wang at intel.com>
> ---
>  lib/librte_hash/rte_cuckoo_hash.c    | 39
> +++++++++++++++++++++++++++++++-----
>  lib/librte_hash/rte_hash.h           | 11 ++++++++++
>  lib/librte_hash/rte_hash_version.map |  8 ++++++++
>  test/test/test_hash.c                | 12 +++++++++++
>  test/test/test_hash_multiwriter.c    |  9 +++++++++
>  5 files changed, 74 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/librte_hash/rte_cuckoo_hash.c
> b/lib/librte_hash/rte_cuckoo_hash.c
> index a5bb4d4..3dff871 100644
> --- a/lib/librte_hash/rte_cuckoo_hash.c
> +++ b/lib/librte_hash/rte_cuckoo_hash.c
> @@ -133,13 +133,13 @@ rte_hash_create(const struct rte_hash_parameters
> *params)
>  		 * except for the first cache
>  		 */
>  		num_key_slots = params->entries + (RTE_MAX_LCORE - 1) *
> -					LCORE_CACHE_SIZE + 1;
> +					(LCORE_CACHE_SIZE - 1) + 1;

This and the other changes made outside the new rte_hash_count API can be done in a different patch.
If this was an issue on the calculation of key slots, it should be marked as a fix and then
a patch with the new API can follow, with the tests.

...

> 
> +int32_t
> +rte_hash_count(struct rte_hash *h)
> +{
> +	uint32_t tot_ring_cnt, cached_cnt = 0;
> +	uint32_t i, ret;
> +
> +	if (h == NULL || h->free_slots == NULL)

I don't think the check on free_slots is necessary,
since rte_hash_create is already checking that.

...

> --- a/lib/librte_hash/rte_hash.h
> +++ b/lib/librte_hash/rte_hash.h
> @@ -127,6 +127,17 @@ void
>  rte_hash_reset(struct rte_hash *h);
> 
>  /**
> + * Return the number of keys in the hash table
> + * @param h
> + *  Hash table to query from
> + * @return
> + *   - -EINVAL if parameters are invalid
> + *   - A value indicating how many keys inserted in the table.

"how many keys were inserted"