Re: [dpdk-dev] [RFC PATCH 4/6] mempool: add a function to flush default cache

[Olivier MATZ]

On Fri, Nov 24, 2017 at 04:06:29PM +0000, Andrew Rybchenko wrote:
> From: "Artem V. Andreev" <artem.andr...@oktetlabs.ru>
> 
> Mempool get/put API cares about cache itself, but sometimes it is
> required to flush the cache explicitly.

I don't disagree, but do you have some use-case in mind?


> Also dedicated API allows to decouple it from block get API (to be
> added) and provides more fine-grained control.
> 
> Signed-off-by: Artem V. Andreev <artem.andr...@oktetlabs.ru>
> Signed-off-by: Andrew Rybchenko <arybche...@solarflare.com>
> ---
>  lib/librte_mempool/rte_mempool.h | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/lib/librte_mempool/rte_mempool.h 
> b/lib/librte_mempool/rte_mempool.h
> index 9bcb8b7..3a52b93 100644
> --- a/lib/librte_mempool/rte_mempool.h
> +++ b/lib/librte_mempool/rte_mempool.h
> @@ -1161,6 +1161,22 @@ rte_mempool_default_cache(struct rte_mempool *mp, 
> unsigned lcore_id)
>  }
>  
>  /**
> + * Ensure that a default per-lcore mempool cache is flushed, if it is present
> + *
> + * @param mp
> + *   A pointer to the mempool structure.
> + */
> +static __rte_always_inline void
> +rte_mempool_ensure_cache_flushed(struct rte_mempool *mp)
> +{
> +     struct rte_mempool_cache *cache;
> +     cache = rte_mempool_default_cache(mp, rte_lcore_id());
> +     if (cache != NULL && cache->len > 0)
> +             rte_mempool_cache_flush(cache, mp);
> +}
> +

We already have rte_mempool_cache_flush().
Why not just extending it instead of adding a new function?

I mean:

    static __rte_always_inline void
    rte_mempool_cache_flush(struct rte_mempool_cache *cache,
                        struct rte_mempool *mp)
    {
   +    if (cache == NULL)
   +            cache = rte_mempool_default_cache(mp, rte_lcore_id());
   +    if (cache == NULL || cache->len == 0)
   +            return;
        rte_mempool_ops_enqueue_bulk(mp, cache->objs, cache->len);
        cache->len = 0;
    }