Re: [PATCH v3] lib/hash: add defer queue reclaim API

[Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>]

Apologies for the late reply. Looks good, few nits inline.

Can you please some simple unit tests?

> On Apr 4, 2024, at 5:11 AM, Abdullah Ömer Yamaç <aomeryamac@gmail.com> wrote:
> 
> Hello, 
> Could you check the last commit?
> Thanks
> 
> On Thu, Mar 14, 2024 at 10:04 AM Abdullah Ömer Yamaç <aomeryamac@gmail.com> wrote:
> Hello,
> Is there any other comment on this? 
> 
> On Wed, Mar 6, 2024 at 1:13 PM Abdullah Ömer Yamaç <aomeryamac@gmail.com> wrote:
> This patch adds a new feature to the hash library to allow the user to
> reclaim the defer queue. This is useful when the user wants to force
> reclaim resources that are not being used. This API is only available
> if the RCU is enabled.
> 
> Signed-off-by: Abdullah Ömer Yamaç <aomeryamac@gmail.com>
> ---
>  lib/hash/rte_cuckoo_hash.c | 23 +++++++++++++++++++++++
>  lib/hash/rte_hash.h        | 24 ++++++++++++++++++++++++
>  lib/hash/version.map       |  6 ++++++
>  3 files changed, 53 insertions(+)
> 
> diff --git a/lib/hash/rte_cuckoo_hash.c b/lib/hash/rte_cuckoo_hash.c
> index 9cf94645f6..1c360fa38b 100644
> --- a/lib/hash/rte_cuckoo_hash.c
> +++ b/lib/hash/rte_cuckoo_hash.c
> @@ -1588,6 +1588,29 @@ rte_hash_rcu_qsbr_add(struct rte_hash *h, struct rte_hash_rcu_config *cfg)
>         return 0;
>  }
> 
> +int
> +rte_hash_rcu_qsbr_dq_reclaim(struct rte_hash *h, unsigned int *freed,
> +               unsigned int *pending, unsigned int *available)
> +{
> +       int ret;
> +
> +       if (h->hash_rcu_cfg == NULL) {
Please check for ‘h’ being NULL.

> +               rte_errno = EINVAL;
> +               return -1;
Return value should be positive 1 as per the API definition below

> +       }
> +
> +       ret = rte_rcu_qsbr_dq_reclaim(h->dq, h->hash_rcu_cfg->max_reclaim_size,
> +                                                       freed, pending, available);
> +       if (ret != 0) {
> +               HASH_LOG(ERR,
> +                       "%s: could not reclaim the defer queue in hash table",
> +                               __func__);
> +               return -1;
> +       }
> +
> +       return 0;
> +}
> +
>  static inline void
>  remove_entry(const struct rte_hash *h, struct rte_hash_bucket *bkt,
>                 unsigned int i)
> diff --git a/lib/hash/rte_hash.h b/lib/hash/rte_hash.h
> index 7ecc021111..edfa262aca 100644
> --- a/lib/hash/rte_hash.h
> +++ b/lib/hash/rte_hash.h
> @@ -674,6 +674,30 @@ rte_hash_iterate(const struct rte_hash *h, const void **key, void **data, uint32
>   */
>  int rte_hash_rcu_qsbr_add(struct rte_hash *h, struct rte_hash_rcu_config *cfg);
> 
> +/**
> + * Reclaim resources from the defer queue.
> + * This API reclaim the resources from the defer queue if rcu is enabled.
> + *
> + * @param h
> + *   The hash object to reclaim resources.
> + * @param freed
> + *   Number of resources that were freed.
> + * @param pending
> + *   Number of resources pending on the defer queue.
> + *   This number might not be accurate if multi-thread safety is configured.
> + * @param available
> + *   Number of resources that can be added to the defer queue.
> + *   This number might not be accurate if multi-thread safety is configured.
> + * @return
> + *   On success - 0
> + *   On error - 1 with error code set in rte_errno.
> + *   Possible rte_errno codes are:
> + *   - EINVAL - invalid pointer
> + */
> +__rte_experimental
> +int rte_hash_rcu_qsbr_dq_reclaim(struct rte_hash *h, unsigned int *freed,
> +               unsigned int *pending, unsigned int *available);
> +
>  #ifdef __cplusplus
>  }
>  #endif
> diff --git a/lib/hash/version.map b/lib/hash/version.map
> index 6b2afebf6b..fac7f81e6f 100644
> --- a/lib/hash/version.map
> +++ b/lib/hash/version.map
> @@ -48,3 +48,9 @@ DPDK_24 {
> 
>         local: *;
>  };
> +
> +EXPERIMENTAL {
> +       global:
> +
> +       rte_hash_rcu_qsbr_dq_reclaim;
> +};
> \ No newline at end of file
> -- 
> 2.34.1
>