Re: [PATCH v5 1/3] mempool: support external handler

[Jerin Jacob <jerin.jacob@caviumnetworks.com>]

On Thu, May 19, 2016 at 02:44:59PM +0100, David Hunt wrote:
> Until now, the objects stored in mempool mempool were internally stored a
> ring. This patch introduce the possibility to register external handlers
> replacing the ring.
> 
> The default behavior remains unchanged, but calling the new function
> rte_mempool_set_handler() right after rte_mempool_create_empty() allows to
> change the handler that will be used when populating the mempool.
> 
> v5 changes: rebasing on top of 35 patch set mempool work.
> 
> Signed-off-by: David Hunt <david.hunt@intel.com>
> Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
> ---
>  app/test/test_mempool_perf.c               |   1 -
>  lib/librte_mempool/Makefile                |   2 +
>  lib/librte_mempool/rte_mempool.c           |  73 ++++------
>  lib/librte_mempool/rte_mempool.h           | 212 +++++++++++++++++++++++++----
>  lib/librte_mempool/rte_mempool_default.c   | 147 ++++++++++++++++++++
>  lib/librte_mempool/rte_mempool_handler.c   | 139 +++++++++++++++++++
>  lib/librte_mempool/rte_mempool_version.map |   4 +
>  7 files changed, 506 insertions(+), 72 deletions(-)
>  create mode 100644 lib/librte_mempool/rte_mempool_default.c
>  create mode 100644 lib/librte_mempool/rte_mempool_handler.c
> 
> diff --git a/app/test/test_mempool_perf.c b/app/test/test_mempool_perf.c
> index cdc02a0..091c1df 100644
> --- a/app/test/test_mempool_perf.c
> +++ b/app/test/test_mempool_perf.c
> @@ -161,7 +161,6 @@ per_lcore_mempool_test(__attribute__((unused)) void *arg)
>  							   n_get_bulk);
>  				if (unlikely(ret < 0)) {
>  					rte_mempool_dump(stdout, mp);
> -					rte_ring_dump(stdout, mp->ring);
>  					/* in this case, objects are lost... */
>  					return -1;
>  				}
> diff --git a/lib/librte_mempool/Makefile b/lib/librte_mempool/Makefile
> index 43423e0..f19366e 100644
> --- a/lib/librte_mempool/Makefile
> +++ b/lib/librte_mempool/Makefile
> @@ -42,6 +42,8 @@ LIBABIVER := 2
>  
>  # all source are stored in SRCS-y
>  SRCS-$(CONFIG_RTE_LIBRTE_MEMPOOL) +=  rte_mempool.c
> +SRCS-$(CONFIG_RTE_LIBRTE_MEMPOOL) +=  rte_mempool_handler.c
> +SRCS-$(CONFIG_RTE_LIBRTE_MEMPOOL) +=  rte_mempool_default.c
>  # install includes
>  SYMLINK-$(CONFIG_RTE_LIBRTE_MEMPOOL)-include := rte_mempool.h
>  
> diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
> index 1ab6701..6ec2b3f 100644
> --- a/lib/librte_mempool/rte_mempool.c
> +++ b/lib/librte_mempool/rte_mempool.c
> @@ -148,7 +148,7 @@ mempool_add_elem(struct rte_mempool *mp, void *obj, phys_addr_t physaddr)
>  #endif
>  
>  	/* enqueue in ring */
> -	rte_ring_sp_enqueue(mp->ring, obj);
> +	rte_mempool_ext_put_bulk(mp, &obj, 1);
>  }
>  
>  /* call obj_cb() for each mempool element */
> @@ -300,40 +300,6 @@ rte_mempool_xmem_usage(__rte_unused void *vaddr, uint32_t elt_num,
>  	return (size_t)paddr_idx << pg_shift;
>  }
>  
> -/* create the internal ring */
> -static int
> -rte_mempool_ring_create(struct rte_mempool *mp)
> -{
> -	int rg_flags = 0, ret;
> -	char rg_name[RTE_RING_NAMESIZE];
> -	struct rte_ring *r;
> -
> -	ret = snprintf(rg_name, sizeof(rg_name),
> -		RTE_MEMPOOL_MZ_FORMAT, mp->name);
> -	if (ret < 0 || ret >= (int)sizeof(rg_name))
> -		return -ENAMETOOLONG;
> -
> -	/* ring flags */
> -	if (mp->flags & MEMPOOL_F_SP_PUT)
> -		rg_flags |= RING_F_SP_ENQ;
> -	if (mp->flags & MEMPOOL_F_SC_GET)
> -		rg_flags |= RING_F_SC_DEQ;
> -
> -	/* Allocate the ring that will be used to store objects.
> -	 * Ring functions will return appropriate errors if we are
> -	 * running as a secondary process etc., so no checks made
> -	 * in this function for that condition.
> -	 */
> -	r = rte_ring_create(rg_name, rte_align32pow2(mp->size + 1),
> -		mp->socket_id, rg_flags);
> -	if (r == NULL)
> -		return -rte_errno;
> -
> -	mp->ring = r;
> -	mp->flags |= MEMPOOL_F_RING_CREATED;
> -	return 0;
> -}
> -
>  /* free a memchunk allocated with rte_memzone_reserve() */
>  static void
>  rte_mempool_memchunk_mz_free(__rte_unused struct rte_mempool_memhdr *memhdr,
> @@ -351,7 +317,7 @@ rte_mempool_free_memchunks(struct rte_mempool *mp)
>  	void *elt;
>  
>  	while (!STAILQ_EMPTY(&mp->elt_list)) {
> -		rte_ring_sc_dequeue(mp->ring, &elt);
> +		rte_mempool_ext_get_bulk(mp, &elt, 1);
>  		(void)elt;
>  		STAILQ_REMOVE_HEAD(&mp->elt_list, next);
>  		mp->populated_size--;
> @@ -380,15 +346,18 @@ rte_mempool_populate_phys(struct rte_mempool *mp, char *vaddr,
>  	unsigned i = 0;
>  	size_t off;
>  	struct rte_mempool_memhdr *memhdr;
> -	int ret;
>  
>  	/* create the internal ring if not already done */
>  	if ((mp->flags & MEMPOOL_F_RING_CREATED) == 0) {
> -		ret = rte_mempool_ring_create(mp);
> -		if (ret < 0)
> -			return ret;
> +		rte_errno = 0;
> +		mp->pool = rte_mempool_ext_alloc(mp);
> +		if (mp->pool == NULL) {
> +			if (rte_errno == 0)
> +				return -EINVAL;
> +			else
> +				return -rte_errno;
> +		}
>  	}
> -
>  	/* mempool is already populated */
>  	if (mp->populated_size >= mp->size)
>  		return -ENOSPC;
> @@ -700,7 +669,7 @@ rte_mempool_free(struct rte_mempool *mp)
>  	rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
>  
>  	rte_mempool_free_memchunks(mp);
> -	rte_ring_free(mp->ring);
> +	rte_mempool_ext_free(mp);
>  	rte_memzone_free(mp->mz);
>  }
>  
> @@ -812,6 +781,20 @@ rte_mempool_create_empty(const char *name, unsigned n, unsigned elt_size,
>  		RTE_PTR_ADD(mp, MEMPOOL_HEADER_SIZE(mp, 0));
>  
>  	te->data = mp;
> +
> +	/*
> +	 * Since we have 4 combinations of the SP/SC/MP/MC examine the flags to
> +	 * set the correct index into the handler table.
> +	 */
> +	if (flags & (MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET))
> +		rte_mempool_set_handler(mp, "ring_sp_sc");
> +	else if (flags & MEMPOOL_F_SP_PUT)
> +		rte_mempool_set_handler(mp, "ring_sp_mc");
> +	else if (flags & MEMPOOL_F_SC_GET)
> +		rte_mempool_set_handler(mp, "ring_mp_sc");
> +	else
> +		rte_mempool_set_handler(mp, "ring_mp_mc");

IMO, We should decouple the implementation specific flags of _a_
external pool manager implementation from the generic rte_mempool_create_empty
function as going further when we introduce new flags for custom HW accelerated
external pool manager then this common code will be bloated.

> +
>  	rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
>  	TAILQ_INSERT_TAIL(mempool_list, te, next);
>  	rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
> @@ -927,7 +910,7 @@ rte_mempool_count(const struct rte_mempool *mp)
>  	unsigned count;
>  	unsigned lcore_id;
>  
> -	count = rte_ring_count(mp->ring);
> +	count = rte_mempool_ext_get_count(mp);
>  
>  	if (mp->cache_size == 0)
>  		return count;
> @@ -1120,7 +1103,7 @@ rte_mempool_dump(FILE *f, struct rte_mempool *mp)
>  
>  	fprintf(f, "mempool <%s>@%p\n", mp->name, mp);
>  	fprintf(f, "  flags=%x\n", mp->flags);
> -	fprintf(f, "  ring=<%s>@%p\n", mp->ring->name, mp->ring);
> +	fprintf(f, "  pool=%p\n", mp->pool);
>  	fprintf(f, "  phys_addr=0x%" PRIx64 "\n", mp->mz->phys_addr);
>  	fprintf(f, "  nb_mem_chunks=%u\n", mp->nb_mem_chunks);
>  	fprintf(f, "  size=%"PRIu32"\n", mp->size);
> @@ -1141,7 +1124,7 @@ rte_mempool_dump(FILE *f, struct rte_mempool *mp)
>  	}
>  
>  	cache_count = rte_mempool_dump_cache(f, mp);
> -	common_count = rte_ring_count(mp->ring);
> +	common_count = rte_mempool_ext_get_count(mp);
>  	if ((cache_count + common_count) > mp->size)
>  		common_count = mp->size - cache_count;
>  	fprintf(f, "  common_pool_count=%u\n", common_count);
> diff --git a/lib/librte_mempool/rte_mempool.h b/lib/librte_mempool/rte_mempool.h
> index 60339bd..ed2c110 100644
> --- a/lib/librte_mempool/rte_mempool.h
> +++ b/lib/librte_mempool/rte_mempool.h
> @@ -67,6 +67,7 @@
>  #include <inttypes.h>
>  #include <sys/queue.h>
>  
> +#include <rte_spinlock.h>
>  #include <rte_log.h>
>  #include <rte_debug.h>
>  #include <rte_lcore.h>
> @@ -203,7 +204,15 @@ struct rte_mempool_memhdr {
>   */
>  struct rte_mempool {
>  	char name[RTE_MEMPOOL_NAMESIZE]; /**< Name of mempool. */
> -	struct rte_ring *ring;           /**< Ring to store objects. */
> +	void *pool;                      /**< Ring or ext-pool to store objects. */
> +	/**
> +	 * Index into the array of structs containing callback fn pointers.
> +	 * We're using an index here rather than pointers to the callbacks
> +	 * to facilitate any secondary processes that may want to use
> +	 * this mempool. Any function pointers stored in the mempool
> +	 * directly would not be valid for secondary processes.
> +	 */
> +	int32_t handler_idx;
>  	const struct rte_memzone *mz;    /**< Memzone where pool is allocated */
>  	int flags;                       /**< Flags of the mempool. */
>  	int socket_id;                   /**< Socket id passed at mempool creation. */
> @@ -325,6 +334,175 @@ void rte_mempool_check_cookies(const struct rte_mempool *mp,
>  #define __mempool_check_cookies(mp, obj_table_const, n, free) do {} while(0)
>  #endif /* RTE_LIBRTE_MEMPOOL_DEBUG */
>  
> +#define RTE_MEMPOOL_HANDLER_NAMESIZE 32 /**< Max length of handler name. */
> +
> +/** Allocate the external pool. */
> +typedef void *(*rte_mempool_alloc_t)(struct rte_mempool *mp);
> +
> +/** Free the external pool. */
> +typedef void (*rte_mempool_free_t)(void *p);
> +
> +/** Put an object in the external pool. */
> +typedef int (*rte_mempool_put_t)(void *p, void * const *obj_table, unsigned n);
> +
> +/** Get an object from the external pool. */
> +typedef int (*rte_mempool_get_t)(void *p, void **obj_table, unsigned n);
> +
> +/** Return the number of available objects in the external pool. */
> +typedef unsigned (*rte_mempool_get_count)(void *p);
> +
> +/** Structure defining a mempool handler. */
> +struct rte_mempool_handler {
> +	char name[RTE_MEMPOOL_HANDLER_NAMESIZE]; /**< Name of mempool handler */
> +	rte_mempool_alloc_t alloc;       /**< Allocate the external pool. */
> +	rte_mempool_free_t free;         /**< Free the external pool. */
> +	rte_mempool_put_t put;           /**< Put an object. */
> +	rte_mempool_get_t get;           /**< Get an object. */
> +	rte_mempool_get_count get_count; /**< Get the number of available objs. */
> +} __rte_cache_aligned;
> +
> +#define RTE_MEMPOOL_MAX_HANDLER_IDX 16  /**< Max number of registered handlers */
> +
> +/** Structure storing the table of registered handlers. */
> +struct rte_mempool_handler_table {
> +	rte_spinlock_t sl;     /**< Spinlock for add/delete. */
> +	uint32_t num_handlers; /**< Number of handlers in the table. */
> +	/** Storage for all possible handlers. */
> +	struct rte_mempool_handler handler[RTE_MEMPOOL_MAX_HANDLER_IDX];
> +};

add __rte_cache_aligned to this structure to avoid "handler" memory
cacheline being shared with other variables

> +
> +/** Array of registered handlers */
> +extern struct rte_mempool_handler_table rte_mempool_handler_table;
> +
> +/**
> + * @internal Get the mempool handler from its index.
> + *
> + * @param handler_idx
> + *   The index of the handler in the handler table. It must be a valid
> + *   index: (0 <= idx < num_handlers).
> + * @return
> + *   The pointer to the handler in the table.
> + */
> +static struct rte_mempool_handler *

inline?

> +rte_mempool_handler_get(int handler_idx)
> +{
> +	return &rte_mempool_handler_table.handler[handler_idx];
> +}
> +
> +/**
> + * @internal wrapper for external mempool manager alloc callback.
> + *
> + * @param mp
> + *   Pointer to the memory pool.
> + * @return
> + *   The opaque pointer to the external pool.
> + */
> +void *
> +rte_mempool_ext_alloc(struct rte_mempool *mp);
> +
> +/**
> + * @internal wrapper for external mempool manager get callback.
> + *
> + * @param mp
> + *   Pointer to the memory pool.
> + * @param obj_table
> + *   Pointer to a table of void * pointers (objects).
> + * @param n
> + *   Number of objects to get.
> + * @return
> + *   - 0: Success; got n objects.
> + *   - <0: Error; code of handler get function.
> + */
> +static inline int
> +rte_mempool_ext_get_bulk(struct rte_mempool *mp, void **obj_table, unsigned n)
> +{
> +	struct rte_mempool_handler *handler;
> +
> +	handler = rte_mempool_handler_get(mp->handler_idx);
> +	return handler->get(mp->pool, obj_table, n);
> +}
> +
> +/**
> + * @internal wrapper for external mempool manager put callback.
> + *
> + * @param mp
> + *   Pointer to the memory pool.
> + * @param obj_table
> + *   Pointer to a table of void * pointers (objects).
> + * @param n
> + *   Number of objects to put.
> + * @return
> + *   - 0: Success; n objects supplied.
> + *   - <0: Error; code of handler put function.
> + */
> +static inline int
> +rte_mempool_ext_put_bulk(struct rte_mempool *mp, void * const *obj_table,
> +		unsigned n)
> +{
> +	struct rte_mempool_handler *handler;
> +
> +	handler = rte_mempool_handler_get(mp->handler_idx);
> +	return handler->put(mp->pool, obj_table, n);
> +}
> +
> +/**
> + * @internal wrapper for external mempool manager get_count callback.
> + *
> + * @param mp
> + *   Pointer to the memory pool.
> + * @return
> + *   The number of available objects in the external pool.
> + */
> +unsigned
> +rte_mempool_ext_get_count(const struct rte_mempool *mp);
> +
> +/**
> + * @internal wrapper for external mempool manager free callback.
> + *
> + * @param mp
> + *   Pointer to the memory pool.
> + */
> +void
> +rte_mempool_ext_free(struct rte_mempool *mp);
> +
> +/**
> + * Set the handler of a mempool
> + *
> + * This can only be done on a mempool that is not populated, i.e. just after
> + * a call to rte_mempool_create_empty().
> + *
> + * @param mp
> + *   Pointer to the memory pool.
> + * @param name
> + *   Name of the handler.
> + * @return
> + *   - 0: Sucess; the new handler is configured.
> + *   - <0: Error (errno)
> + */
> +int
> +rte_mempool_set_handler(struct rte_mempool *mp, const char *name);
> +
> +/**
> + * Register an external pool handler.
> + *
> + * @param h
> + *   Pointer to the external pool handler
> + * @return
> + *   - >=0: Sucess; return the index of the handler in the table.
> + *   - <0: Error (errno)
> + */
> +int rte_mempool_handler_register(struct rte_mempool_handler *h);
> +
> +/**
> + * Macro to statically register an external pool handler.
> + */
> +#define MEMPOOL_REGISTER_HANDLER(h)					\
> +	void mp_hdlr_init_##h(void);					\
> +	void __attribute__((constructor, used)) mp_hdlr_init_##h(void)	\
> +	{								\
> +		rte_mempool_handler_register(&h);			\
> +	}
> +
>  /**
>   * An object callback function for mempool.
>   *
> @@ -736,7 +914,7 @@ void rte_mempool_dump(FILE *f, struct rte_mempool *mp);
>   */
>  static inline void __attribute__((always_inline))
>  __mempool_put_bulk(struct rte_mempool *mp, void * const *obj_table,
> -		    unsigned n, int is_mp)
> +		    unsigned n, __rte_unused int is_mp)
>  {
>  	struct rte_mempool_cache *cache;
>  	uint32_t index;
> @@ -774,7 +952,7 @@ __mempool_put_bulk(struct rte_mempool *mp, void * const *obj_table,
>  	cache->len += n;
>  
>  	if (cache->len >= flushthresh) {
> -		rte_ring_mp_enqueue_bulk(mp->ring, &cache->objs[cache_size],
> +		rte_mempool_ext_put_bulk(mp, &cache->objs[cache_size],
>  				cache->len - cache_size);
>  		cache->len = cache_size;
>  	}
> @@ -782,26 +960,10 @@ __mempool_put_bulk(struct rte_mempool *mp, void * const *obj_table,
>  	return;
>  
>  ring_enqueue:
> -
>  	/* push remaining objects in ring */
> -#ifdef RTE_LIBRTE_MEMPOOL_DEBUG
> -	if (is_mp) {
> -		if (rte_ring_mp_enqueue_bulk(mp->ring, obj_table, n) < 0)
> -			rte_panic("cannot put objects in mempool\n");
> -	}
> -	else {
> -		if (rte_ring_sp_enqueue_bulk(mp->ring, obj_table, n) < 0)
> -			rte_panic("cannot put objects in mempool\n");
> -	}
> -#else
> -	if (is_mp)
> -		rte_ring_mp_enqueue_bulk(mp->ring, obj_table, n);
> -	else
> -		rte_ring_sp_enqueue_bulk(mp->ring, obj_table, n);
> -#endif
> +	rte_mempool_ext_put_bulk(mp, obj_table, n);
>  }
>  
> -
>  /**
>   * Put several objects back in the mempool (multi-producers safe).
>   *
> @@ -922,7 +1084,7 @@ rte_mempool_put(struct rte_mempool *mp, void *obj)
>   */
>  static inline int __attribute__((always_inline))
>  __mempool_get_bulk(struct rte_mempool *mp, void **obj_table,
> -		   unsigned n, int is_mc)
> +		   unsigned n, __rte_unused int is_mc)
>  {
>  	int ret;
>  	struct rte_mempool_cache *cache;
> @@ -945,7 +1107,8 @@ __mempool_get_bulk(struct rte_mempool *mp, void **obj_table,
>  		uint32_t req = n + (cache_size - cache->len);
>  
>  		/* How many do we require i.e. number to fill the cache + the request */
> -		ret = rte_ring_mc_dequeue_bulk(mp->ring, &cache->objs[cache->len], req);
> +		ret = rte_mempool_ext_get_bulk(mp,

This makes inline function to a function pointer. Nothing wrong in
that. However, Do you see any performance drop with "local cache" only
use case?

http://dpdk.org/dev/patchwork/patch/12993/

> +			&cache->objs[cache->len], req);
>  		if (unlikely(ret < 0)) {
>  			/*
>  			 * In the offchance that we are buffer constrained,
> @@ -972,10 +1135,7 @@ __mempool_get_bulk(struct rte_mempool *mp, void **obj_table,
>  ring_dequeue:
>  
>  	/* get remaining objects from ring */
> -	if (is_mc)
> -		ret = rte_ring_mc_dequeue_bulk(mp->ring, obj_table, n);
> -	else
> -		ret = rte_ring_sc_dequeue_bulk(mp->ring, obj_table, n);
> +	ret = rte_mempool_ext_get_bulk(mp, obj_table, n);
>  
>  	if (ret < 0)
>  		__MEMPOOL_STAT_ADD(mp, get_fail, n);
> diff --git a/lib/librte_mempool/rte_mempool_default.c b/lib/librte_mempool/rte_mempool_default.c
> new file mode 100644
> index 0000000..a6ac65a
> --- /dev/null
> +++ b/lib/librte_mempool/rte_mempool_default.c
> @@ -0,0 +1,147 @@
> +/*-
> + *   BSD LICENSE
> + *
> + *   Copyright(c) 2010-2016 Intel Corporation. All rights reserved.
> + *   All rights reserved.
> + *
> + *   Redistribution and use in source and binary forms, with or without
> + *   modification, are permitted provided that the following conditions
> + *   are met:
> + *
> + *     * Redistributions of source code must retain the above copyright
> + *       notice, this list of conditions and the following disclaimer.
> + *     * Redistributions in binary form must reproduce the above copyright
> + *       notice, this list of conditions and the following disclaimer in
> + *       the documentation and/or other materials provided with the
> + *       distribution.
> + *     * Neither the name of Intel Corporation nor the names of its
> + *       contributors may be used to endorse or promote products derived
> + *       from this software without specific prior written permission.
> + *
> + *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
> + *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
> + *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
> + *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
> + *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
> + *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
> + *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
> + *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
> + *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> + *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
> + *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> + */
> +
> +#include <stdio.h>
> +#include <string.h>
> +
> +#include <rte_errno.h>
> +#include <rte_ring.h>
> +#include <rte_mempool.h>
> +
> +static int
> +common_ring_mp_put(void *p, void * const *obj_table, unsigned n)
> +{
> +	return rte_ring_mp_enqueue_bulk((struct rte_ring *)p, obj_table, n);
> +}
> +
> +static int
> +common_ring_sp_put(void *p, void * const *obj_table, unsigned n)
> +{
> +	return rte_ring_sp_enqueue_bulk((struct rte_ring *)p, obj_table, n);
> +}
> +
> +static int
> +common_ring_mc_get(void *p, void **obj_table, unsigned n)
> +{
> +	return rte_ring_mc_dequeue_bulk((struct rte_ring *)p, obj_table, n);
> +}
> +
> +static int
> +common_ring_sc_get(void *p, void **obj_table, unsigned n)
> +{
> +	return rte_ring_sc_dequeue_bulk((struct rte_ring *)p, obj_table, n);
> +}
> +
> +static unsigned
> +common_ring_get_count(void *p)
> +{
> +	return rte_ring_count((struct rte_ring *)p);
> +}
> +
> +
> +static void *
> +common_ring_alloc(struct rte_mempool *mp)
> +{
> +	int rg_flags = 0, ret;
> +	char rg_name[RTE_RING_NAMESIZE];
> +	struct rte_ring *r;
> +
> +	ret = snprintf(rg_name, sizeof(rg_name),
> +		RTE_MEMPOOL_MZ_FORMAT, mp->name);
> +	if (ret < 0 || ret >= (int)sizeof(rg_name)) {
> +		rte_errno = ENAMETOOLONG;
> +		return NULL;
> +	}
> +
> +	/* ring flags */
> +	if (mp->flags & MEMPOOL_F_SP_PUT)
> +		rg_flags |= RING_F_SP_ENQ;
> +	if (mp->flags & MEMPOOL_F_SC_GET)
> +		rg_flags |= RING_F_SC_DEQ;
> +
> +	/* Allocate the ring that will be used to store objects.
> +	 * Ring functions will return appropriate errors if we are
> +	 * running as a secondary process etc., so no checks made
> +	 * in this function for that condition. */
> +	r = rte_ring_create(rg_name, rte_align32pow2(mp->size + 1),
> +		mp->socket_id, rg_flags);
> +
> +	return r;
> +}
> +
> +static void
> +common_ring_free(void *p)
> +{
> +	rte_ring_free((struct rte_ring *)p);
> +}
> +
> +static struct rte_mempool_handler handler_mp_mc = {
> +	.name = "ring_mp_mc",
> +	.alloc = common_ring_alloc,
> +	.free = common_ring_free,
> +	.put = common_ring_mp_put,
> +	.get = common_ring_mc_get,
> +	.get_count = common_ring_get_count,
> +};
> +
> +static struct rte_mempool_handler handler_sp_sc = {
> +	.name = "ring_sp_sc",
> +	.alloc = common_ring_alloc,
> +	.free = common_ring_free,
> +	.put = common_ring_sp_put,
> +	.get = common_ring_sc_get,
> +	.get_count = common_ring_get_count,
> +};
> +
> +static struct rte_mempool_handler handler_mp_sc = {
> +	.name = "ring_mp_sc",
> +	.alloc = common_ring_alloc,
> +	.free = common_ring_free,
> +	.put = common_ring_mp_put,
> +	.get = common_ring_sc_get,
> +	.get_count = common_ring_get_count,
> +};
> +
> +static struct rte_mempool_handler handler_sp_mc = {
> +	.name = "ring_sp_mc",
> +	.alloc = common_ring_alloc,
> +	.free = common_ring_free,
> +	.put = common_ring_sp_put,
> +	.get = common_ring_mc_get,
> +	.get_count = common_ring_get_count,
> +};
> +
> +MEMPOOL_REGISTER_HANDLER(handler_mp_mc);
> +MEMPOOL_REGISTER_HANDLER(handler_sp_sc);
> +MEMPOOL_REGISTER_HANDLER(handler_mp_sc);
> +MEMPOOL_REGISTER_HANDLER(handler_sp_mc);
> diff --git a/lib/librte_mempool/rte_mempool_handler.c b/lib/librte_mempool/rte_mempool_handler.c
> new file mode 100644
> index 0000000..78611f8
> --- /dev/null
> +++ b/lib/librte_mempool/rte_mempool_handler.c
> @@ -0,0 +1,139 @@
> +/*-
> + *   BSD LICENSE
> + *
> + *   Copyright(c) 2016 Intel Corporation. All rights reserved.
> + *   Copyright(c) 2016 6WIND S.A.
> + *   All rights reserved.
> + *
> + *   Redistribution and use in source and binary forms, with or without
> + *   modification, are permitted provided that the following conditions
> + *   are met:
> + *
> + *     * Redistributions of source code must retain the above copyright
> + *       notice, this list of conditions and the following disclaimer.
> + *     * Redistributions in binary form must reproduce the above copyright
> + *       notice, this list of conditions and the following disclaimer in
> + *       the documentation and/or other materials provided with the
> + *       distribution.
> + *     * Neither the name of Intel Corporation nor the names of its
> + *       contributors may be used to endorse or promote products derived
> + *       from this software without specific prior written permission.
> + *
> + *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
> + *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
> + *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
> + *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
> + *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
> + *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
> + *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
> + *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
> + *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> + *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
> + *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> + */
> +
> +#include <stdio.h>
> +#include <string.h>
> +
> +#include <rte_mempool.h>
> +
> +/* indirect jump table to support external memory pools */
> +struct rte_mempool_handler_table rte_mempool_handler_table = {
> +	.sl =  RTE_SPINLOCK_INITIALIZER ,
> +	.num_handlers = 0
> +};
> +
> +/* add a new handler in rte_mempool_handler_table, return its index */
> +int
> +rte_mempool_handler_register(struct rte_mempool_handler *h)
> +{
> +	struct rte_mempool_handler *handler;
> +	int16_t handler_idx;
> +
> +	rte_spinlock_lock(&rte_mempool_handler_table.sl);
> +
> +	if (rte_mempool_handler_table.num_handlers >= RTE_MEMPOOL_MAX_HANDLER_IDX) {
> +		rte_spinlock_unlock(&rte_mempool_handler_table.sl);
> +		RTE_LOG(ERR, MEMPOOL,
> +			"Maximum number of mempool handlers exceeded\n");
> +		return -ENOSPC;
> +	}
> +
> +	if (h->put == NULL || h->get == NULL || h->get_count == NULL) {
> +		rte_spinlock_unlock(&rte_mempool_handler_table.sl);
> +		RTE_LOG(ERR, MEMPOOL,
> +			"Missing callback while registering mempool handler\n");
> +		return -EINVAL;
> +	}
> +
> +	handler_idx = rte_mempool_handler_table.num_handlers++;
> +	handler = &rte_mempool_handler_table.handler[handler_idx];
> +	snprintf(handler->name, sizeof(handler->name), "%s", h->name);
> +	handler->alloc = h->alloc;
> +	handler->put = h->put;
> +	handler->get = h->get;
> +	handler->get_count = h->get_count;
> +
> +	rte_spinlock_unlock(&rte_mempool_handler_table.sl);
> +
> +	return handler_idx;
> +}
> +
> +/* wrapper to allocate an external pool handler */
> +void *
> +rte_mempool_ext_alloc(struct rte_mempool *mp)
> +{
> +	struct rte_mempool_handler *handler;
> +
> +	handler = rte_mempool_handler_get(mp->handler_idx);
> +	if (handler->alloc == NULL)
> +		return NULL;
> +	return handler->alloc(mp);
> +}
> +
> +/* wrapper to free an external pool handler */
> +void
> +rte_mempool_ext_free(struct rte_mempool *mp)
> +{
> +	struct rte_mempool_handler *handler;
> +
> +	handler = rte_mempool_handler_get(mp->handler_idx);
> +	if (handler->free == NULL)
> +		return;
> +	return handler->free(mp);
> +}
> +
> +/* wrapper to get available objects in an external pool handler */
> +unsigned
> +rte_mempool_ext_get_count(const struct rte_mempool *mp)
> +{
> +	struct rte_mempool_handler *handler;
> +
> +	handler = rte_mempool_handler_get(mp->handler_idx);
> +	return handler->get_count(mp->pool);
> +}
> +
> +/* set the handler of a mempool */
> +int
> +rte_mempool_set_handler(struct rte_mempool *mp, const char *name)
> +{
> +	struct rte_mempool_handler *handler = NULL;
> +	unsigned i;
> +
> +	/* too late, the mempool is already populated */
> +	if (mp->flags & MEMPOOL_F_RING_CREATED)
> +		return -EEXIST;
> +
> +	for (i = 0; i < rte_mempool_handler_table.num_handlers; i++) {
> +		if (!strcmp(name, rte_mempool_handler_table.handler[i].name)) {
> +			handler = &rte_mempool_handler_table.handler[i];
> +			break;
> +		}
> +	}
> +
> +	if (handler == NULL)
> +		return -EINVAL;
> +
> +	mp->handler_idx = i;
> +	return 0;
> +}
> diff --git a/lib/librte_mempool/rte_mempool_version.map b/lib/librte_mempool/rte_mempool_version.map
> index f63461b..a0e9aed 100644
> --- a/lib/librte_mempool/rte_mempool_version.map
> +++ b/lib/librte_mempool/rte_mempool_version.map
> @@ -19,6 +19,8 @@ DPDK_2.0 {
>  DPDK_16.7 {
>  	global:
>  
> +	rte_mempool_handler_table;
> +
>  	rte_mempool_check_cookies;
>  	rte_mempool_obj_iter;
>  	rte_mempool_mem_iter;
> @@ -29,6 +31,8 @@ DPDK_16.7 {
>  	rte_mempool_populate_default;
>  	rte_mempool_populate_anon;
>  	rte_mempool_free;
> +	rte_mempool_set_handler;
> +	rte_mempool_handler_register;
>  
>  	local: *;
>  } DPDK_2.0;
> -- 
> 2.5.5
>