Re: [dpdk-dev] [PATCH] mbuf: remove inconsistent assert statements

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

Hi Adrien,

> 
> An assertion failure occurs in __rte_mbuf_raw_free() (called by a few PMDs)
> when compiling DPDK with CONFIG_RTE_LOG_LEVEL=RTE_LOG_DEBUG and starting
> applications with a log level high enough to trigger it.
> 
> While rte_mbuf_raw_alloc() sets refcount to 1, __rte_mbuf_raw_free()
> expects it to be 0. 
>Considering users are not expected to reset the
> reference count to satisfy assert() and that raw functions are designed on
> purpose without safety belts, remove these checks.

Yes, it refcnt supposed to be set to 0 by __rte_pktmbuf_prefree_seg().
Wright now, it is a user responsibility to make sure refcnt==0 before pushing
mbuf back to the pool.
Not sure why do you consider that wrong?
If the user calls __rte_mbuf_raw_free() manualy it is his responsibility to make
sure mbuf's refcn==0.
BTW, why are you doing it?
The comment clearly states that the function is for internal use:
/**
 * @internal Put mbuf back into its original mempool.
 * The use of that function is reserved for RTE internal needs.
 * Please use rte_pktmbuf_free().
 *
 * @param m
 *   The mbuf to be freed.
 */
static inline void __attribute__((always_inline))
__rte_mbuf_raw_free(struct rte_mbuf *m)

Konstantin

> 
> Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
> ---
>  lib/librte_mbuf/rte_mbuf.h | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> index 11fa06d..7070bb8 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -1108,7 +1108,6 @@ static inline struct rte_mbuf *rte_mbuf_raw_alloc(struct rte_mempool *mp)
>  	if (rte_mempool_get(mp, &mb) < 0)
>  		return NULL;
>  	m = (struct rte_mbuf *)mb;
> -	RTE_ASSERT(rte_mbuf_refcnt_read(m) == 0);
>  	rte_mbuf_refcnt_set(m, 1);
>  	__rte_mbuf_sanity_check(m, 0);
> 
> @@ -1133,7 +1132,6 @@ __rte_mbuf_raw_alloc(struct rte_mempool *mp)
>  static inline void __attribute__((always_inline))
>  __rte_mbuf_raw_free(struct rte_mbuf *m)
>  {
> -	RTE_ASSERT(rte_mbuf_refcnt_read(m) == 0);
>  	rte_mempool_put(m->pool, m);
>  }
> 
> --
> 2.1.4