[dpdk-dev] [PATCH v10 2/6] lib/ring: apis to support configurable element size

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

Current APIs assume ring elements to be pointers. However, in many
use cases, the size can be different. Add new APIs to support
configurable ring element sizes.

Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
Reviewed-by: Gavin Hu <gavin.hu@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
---
 lib/librte_ring/Makefile             |    3 +-
 lib/librte_ring/meson.build          |    4 +
 lib/librte_ring/rte_ring.c           |   41 +-
 lib/librte_ring/rte_ring.h           |    1 +
 lib/librte_ring/rte_ring_elem.h      | 1003 ++++++++++++++++++++++++++
 lib/librte_ring/rte_ring_version.map |    2 +
 6 files changed, 1045 insertions(+), 9 deletions(-)
 create mode 100644 lib/librte_ring/rte_ring_elem.h

diff --git a/lib/librte_ring/Makefile b/lib/librte_ring/Makefile
index 22454b084..917c560ad 100644
--- a/lib/librte_ring/Makefile
+++ b/lib/librte_ring/Makefile
@@ -6,7 +6,7 @@ include $(RTE_SDK)/mk/rte.vars.mk
 # library name
 LIB = librte_ring.a
 
-CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3
+CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3 -DALLOW_EXPERIMENTAL_API
 LDLIBS += -lrte_eal
 
 EXPORT_MAP := rte_ring_version.map
@@ -16,6 +16,7 @@ SRCS-$(CONFIG_RTE_LIBRTE_RING) := rte_ring.c
 
 # install includes
 SYMLINK-$(CONFIG_RTE_LIBRTE_RING)-include := rte_ring.h \
+					rte_ring_elem.h \
 					rte_ring_generic.h \
 					rte_ring_c11_mem.h
 
diff --git a/lib/librte_ring/meson.build b/lib/librte_ring/meson.build
index ca8a435e9..f2f3ccc88 100644
--- a/lib/librte_ring/meson.build
+++ b/lib/librte_ring/meson.build
@@ -3,5 +3,9 @@
 
 sources = files('rte_ring.c')
 headers = files('rte_ring.h',
+		'rte_ring_elem.h',
 		'rte_ring_c11_mem.h',
 		'rte_ring_generic.h')
+
+# rte_ring_create_elem and rte_ring_get_memsize_elem are experimental
+allow_experimental_apis = true
diff --git a/lib/librte_ring/rte_ring.c b/lib/librte_ring/rte_ring.c
index d9b308036..3e15dc398 100644
--- a/lib/librte_ring/rte_ring.c
+++ b/lib/librte_ring/rte_ring.c
@@ -33,6 +33,7 @@
 #include <rte_tailq.h>
 
 #include "rte_ring.h"
+#include "rte_ring_elem.h"
 
 TAILQ_HEAD(rte_ring_list, rte_tailq_entry);
 
@@ -46,23 +47,38 @@ EAL_REGISTER_TAILQ(rte_ring_tailq)
 
 /* return the size of memory occupied by a ring */
 ssize_t
-rte_ring_get_memsize(unsigned count)
+rte_ring_get_memsize_elem(unsigned int esize, unsigned int count)
 {
 	ssize_t sz;
 
+	/* Check if element size is a multiple of 4B */
+	if (esize % 4 != 0) {
+		RTE_LOG(ERR, RING, "element size is not a multiple of 4\n");
+
+		return -EINVAL;
+	}
+
 	/* count must be a power of 2 */
 	if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK )) {
 		RTE_LOG(ERR, RING,
-			"Requested size is invalid, must be power of 2, and "
-			"do not exceed the size limit %u\n", RTE_RING_SZ_MASK);
+			"Requested number of elements is invalid, must be power of 2, and not exceed %u\n",
+			RTE_RING_SZ_MASK);
+
 		return -EINVAL;
 	}
 
-	sz = sizeof(struct rte_ring) + count * sizeof(void *);
+	sz = sizeof(struct rte_ring) + count * esize;
 	sz = RTE_ALIGN(sz, RTE_CACHE_LINE_SIZE);
 	return sz;
 }
 
+/* return the size of memory occupied by a ring */
+ssize_t
+rte_ring_get_memsize(unsigned count)
+{
+	return rte_ring_get_memsize_elem(sizeof(void *), count);
+}
+
 void
 rte_ring_reset(struct rte_ring *r)
 {
@@ -114,10 +130,10 @@ rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
 	return 0;
 }
 
-/* create the ring */
+/* create the ring for a given element size */
 struct rte_ring *
-rte_ring_create(const char *name, unsigned count, int socket_id,
-		unsigned flags)
+rte_ring_create_elem(const char *name, unsigned int esize, unsigned int count,
+		int socket_id, unsigned int flags)
 {
 	char mz_name[RTE_MEMZONE_NAMESIZE];
 	struct rte_ring *r;
@@ -135,7 +151,7 @@ rte_ring_create(const char *name, unsigned count, int socket_id,
 	if (flags & RING_F_EXACT_SZ)
 		count = rte_align32pow2(count + 1);
 
-	ring_size = rte_ring_get_memsize(count);
+	ring_size = rte_ring_get_memsize_elem(esize, count);
 	if (ring_size < 0) {
 		rte_errno = ring_size;
 		return NULL;
@@ -182,6 +198,15 @@ rte_ring_create(const char *name, unsigned count, int socket_id,
 	return r;
 }
 
+/* create the ring */
+struct rte_ring *
+rte_ring_create(const char *name, unsigned count, int socket_id,
+		unsigned flags)
+{
+	return rte_ring_create_elem(name, sizeof(void *), count, socket_id,
+		flags);
+}
+
 /* free the ring */
 void
 rte_ring_free(struct rte_ring *r)
diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
index 2a9f768a1..18fc5d845 100644
--- a/lib/librte_ring/rte_ring.h
+++ b/lib/librte_ring/rte_ring.h
@@ -216,6 +216,7 @@ int rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
  */
 struct rte_ring *rte_ring_create(const char *name, unsigned count,
 				 int socket_id, unsigned flags);
+
 /**
  * De-allocate all memory used by the ring.
  *
diff --git a/lib/librte_ring/rte_ring_elem.h b/lib/librte_ring/rte_ring_elem.h
new file mode 100644
index 000000000..15d79bf2a
--- /dev/null
+++ b/lib/librte_ring/rte_ring_elem.h
@@ -0,0 +1,1003 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 2019 Arm Limited
+ * Copyright (c) 2010-2017 Intel Corporation
+ * Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org
+ * All rights reserved.
+ * Derived from FreeBSD's bufring.h
+ * Used as BSD-3 Licensed with permission from Kip Macy.
+ */
+
+#ifndef _RTE_RING_ELEM_H_
+#define _RTE_RING_ELEM_H_
+
+/**
+ * @file
+ * RTE Ring with user defined element size
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys/queue.h>
+#include <errno.h>
+#include <rte_common.h>
+#include <rte_config.h>
+#include <rte_memory.h>
+#include <rte_lcore.h>
+#include <rte_atomic.h>
+#include <rte_branch_prediction.h>
+#include <rte_memzone.h>
+#include <rte_pause.h>
+
+#include "rte_ring.h"
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Calculate the memory size needed for a ring with given element size
+ *
+ * This function returns the number of bytes needed for a ring, given
+ * the number of elements in it and the size of the element. This value
+ * is the sum of the size of the structure rte_ring and the size of the
+ * memory needed for storing the elements. The value is aligned to a cache
+ * line size.
+ *
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ * @param count
+ *   The number of elements in the ring (must be a power of 2).
+ * @return
+ *   - The memory size needed for the ring on success.
+ *   - -EINVAL - esize is not a multiple of 4 or count provided is not a
+ *		 power of 2.
+ */
+__rte_experimental
+ssize_t rte_ring_get_memsize_elem(unsigned int esize, unsigned int count);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Create a new ring named *name* that stores elements with given size.
+ *
+ * This function uses ``memzone_reserve()`` to allocate memory. Then it
+ * calls rte_ring_init() to initialize an empty ring.
+ *
+ * The new ring size is set to *count*, which must be a power of
+ * two. Water marking is disabled by default. The real usable ring size
+ * is *count-1* instead of *count* to differentiate a free ring from an
+ * empty ring.
+ *
+ * The ring is added in RTE_TAILQ_RING list.
+ *
+ * @param name
+ *   The name of the ring.
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ * @param count
+ *   The number of elements in the ring (must be a power of 2).
+ * @param socket_id
+ *   The *socket_id* argument is the socket identifier in case of
+ *   NUMA. The value can be *SOCKET_ID_ANY* if there is no NUMA
+ *   constraint for the reserved zone.
+ * @param flags
+ *   An OR of the following:
+ *    - RING_F_SP_ENQ: If this flag is set, the default behavior when
+ *      using ``rte_ring_enqueue()`` or ``rte_ring_enqueue_bulk()``
+ *      is "single-producer". Otherwise, it is "multi-producers".
+ *    - RING_F_SC_DEQ: If this flag is set, the default behavior when
+ *      using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``
+ *      is "single-consumer". Otherwise, it is "multi-consumers".
+ * @return
+ *   On success, the pointer to the new allocated ring. NULL on error with
+ *    rte_errno set appropriately. Possible errno values include:
+ *    - E_RTE_NO_CONFIG - function could not get pointer to rte_config structure
+ *    - E_RTE_SECONDARY - function was called from a secondary process instance
+ *    - EINVAL - esize is not a multiple of 4 or count provided is not a
+ *		 power of 2.
+ *    - ENOSPC - the maximum number of memzones has already been allocated
+ *    - EEXIST - a memzone with the same name already exists
+ *    - ENOMEM - no appropriate memory area found in which to create memzone
+ */
+__rte_experimental
+struct rte_ring *rte_ring_create_elem(const char *name, unsigned int esize,
+			unsigned int count, int socket_id, unsigned int flags);
+
+static __rte_always_inline void
+enqueue_elems_32(struct rte_ring *r, const uint32_t size, uint32_t idx,
+		const void *obj_table, uint32_t n)
+{
+	unsigned int i;
+	uint32_t *ring = (uint32_t *)&r[1];
+	const uint32_t *obj = (const uint32_t *)obj_table;
+	if (likely(idx + n < size)) {
+		for (i = 0; i < (n & ~0x7); i += 8, idx += 8) {
+			ring[idx] = obj[i];
+			ring[idx + 1] = obj[i + 1];
+			ring[idx + 2] = obj[i + 2];
+			ring[idx + 3] = obj[i + 3];
+			ring[idx + 4] = obj[i + 4];
+			ring[idx + 5] = obj[i + 5];
+			ring[idx + 6] = obj[i + 6];
+			ring[idx + 7] = obj[i + 7];
+		}
+		switch (n & 0x7) {
+		case 7:
+			ring[idx++] = obj[i++]; /* fallthrough */
+		case 6:
+			ring[idx++] = obj[i++]; /* fallthrough */
+		case 5:
+			ring[idx++] = obj[i++]; /* fallthrough */
+		case 4:
+			ring[idx++] = obj[i++]; /* fallthrough */
+		case 3:
+			ring[idx++] = obj[i++]; /* fallthrough */
+		case 2:
+			ring[idx++] = obj[i++]; /* fallthrough */
+		case 1:
+			ring[idx++] = obj[i++]; /* fallthrough */
+		}
+	} else {
+		for (i = 0; idx < size; i++, idx++)
+			ring[idx] = obj[i];
+		/* Start at the beginning */
+		for (idx = 0; i < n; i++, idx++)
+			ring[idx] = obj[i];
+	}
+}
+
+static __rte_always_inline void
+enqueue_elems_64(struct rte_ring *r, uint32_t prod_head,
+		const void *obj_table, uint32_t n)
+{
+	unsigned int i;
+	const uint32_t size = r->size;
+	uint32_t idx = prod_head & r->mask;
+	uint64_t *ring = (uint64_t *)&r[1];
+	const uint64_t *obj = (const uint64_t *)obj_table;
+	if (likely(idx + n < size)) {
+		for (i = 0; i < (n & ~0x3); i += 4, idx += 4) {
+			ring[idx] = obj[i];
+			ring[idx + 1] = obj[i + 1];
+			ring[idx + 2] = obj[i + 2];
+			ring[idx + 3] = obj[i + 3];
+		}
+		switch (n & 0x3) {
+		case 3:
+			ring[idx++] = obj[i++]; /* fallthrough */
+		case 2:
+			ring[idx++] = obj[i++]; /* fallthrough */
+		case 1:
+			ring[idx++] = obj[i++];
+		}
+	} else {
+		for (i = 0; idx < size; i++, idx++)
+			ring[idx] = obj[i];
+		/* Start at the beginning */
+		for (idx = 0; i < n; i++, idx++)
+			ring[idx] = obj[i];
+	}
+}
+
+static __rte_always_inline void
+enqueue_elems_128(struct rte_ring *r, uint32_t prod_head,
+		const void *obj_table, uint32_t n)
+{
+	unsigned int i;
+	const uint32_t size = r->size;
+	uint32_t idx = prod_head & r->mask;
+	rte_int128_t *ring = (rte_int128_t *)&r[1];
+	const rte_int128_t *obj = (const rte_int128_t *)obj_table;
+	if (likely(idx + n < size)) {
+		for (i = 0; i < (n & ~0x1); i += 2, idx += 2)
+			memcpy((void *)(ring + idx),
+				(const void *)(obj + i), 32);
+		switch (n & 0x1) {
+		case 1:
+			memcpy((void *)(ring + idx),
+				(const void *)(obj + i), 16);
+		}
+	} else {
+		for (i = 0; idx < size; i++, idx++)
+			memcpy((void *)(ring + idx),
+				(const void *)(obj + i), 16);
+		/* Start at the beginning */
+		for (idx = 0; i < n; i++, idx++)
+			memcpy((void *)(ring + idx),
+				(const void *)(obj + i), 16);
+	}
+}
+
+/* the actual enqueue of elements on the ring.
+ * Placed here since identical code needed in both
+ * single and multi producer enqueue functions.
+ */
+static __rte_always_inline void
+enqueue_elems(struct rte_ring *r, uint32_t prod_head, const void *obj_table,
+		uint32_t esize, uint32_t num)
+{
+	/* 8B and 16B copies implemented individually to retain
+	 * the current performance.
+	 */
+	if (esize == 8)
+		enqueue_elems_64(r, prod_head, obj_table, num);
+	else if (esize == 16)
+		enqueue_elems_128(r, prod_head, obj_table, num);
+	else {
+		uint32_t idx, scale, nr_idx, nr_num, nr_size;
+
+		/* Normalize to uint32_t */
+		scale = esize / sizeof(uint32_t);
+		nr_num = num * scale;
+		idx = prod_head & r->mask;
+		nr_idx = idx * scale;
+		nr_size = r->size * scale;
+		enqueue_elems_32(r, nr_size, nr_idx, obj_table, nr_num);
+	}
+}
+
+static __rte_always_inline void
+dequeue_elems_32(struct rte_ring *r, const uint32_t size, uint32_t idx,
+		void *obj_table, uint32_t n)
+{
+	unsigned int i;
+	uint32_t *ring = (uint32_t *)&r[1];
+	uint32_t *obj = (uint32_t *)obj_table;
+	if (likely(idx + n < size)) {
+		for (i = 0; i < (n & ~0x7); i += 8, idx += 8) {
+			obj[i] = ring[idx];
+			obj[i + 1] = ring[idx + 1];
+			obj[i + 2] = ring[idx + 2];
+			obj[i + 3] = ring[idx + 3];
+			obj[i + 4] = ring[idx + 4];
+			obj[i + 5] = ring[idx + 5];
+			obj[i + 6] = ring[idx + 6];
+			obj[i + 7] = ring[idx + 7];
+		}
+		switch (n & 0x7) {
+		case 7:
+			obj[i++] = ring[idx++]; /* fallthrough */
+		case 6:
+			obj[i++] = ring[idx++]; /* fallthrough */
+		case 5:
+			obj[i++] = ring[idx++]; /* fallthrough */
+		case 4:
+			obj[i++] = ring[idx++]; /* fallthrough */
+		case 3:
+			obj[i++] = ring[idx++]; /* fallthrough */
+		case 2:
+			obj[i++] = ring[idx++]; /* fallthrough */
+		case 1:
+			obj[i++] = ring[idx++]; /* fallthrough */
+		}
+	} else {
+		for (i = 0; idx < size; i++, idx++)
+			obj[i] = ring[idx];
+		/* Start at the beginning */
+		for (idx = 0; i < n; i++, idx++)
+			obj[i] = ring[idx];
+	}
+}
+
+static __rte_always_inline void
+dequeue_elems_64(struct rte_ring *r, uint32_t prod_head,
+		void *obj_table, uint32_t n)
+{
+	unsigned int i;
+	const uint32_t size = r->size;
+	uint32_t idx = prod_head & r->mask;
+	uint64_t *ring = (uint64_t *)&r[1];
+	uint64_t *obj = (uint64_t *)obj_table;
+	if (likely(idx + n < size)) {
+		for (i = 0; i < (n & ~0x3); i += 4, idx += 4) {
+			obj[i] = ring[idx];
+			obj[i + 1] = ring[idx + 1];
+			obj[i + 2] = ring[idx + 2];
+			obj[i + 3] = ring[idx + 3];
+		}
+		switch (n & 0x3) {
+		case 3:
+			obj[i++] = ring[idx++]; /* fallthrough */
+		case 2:
+			obj[i++] = ring[idx++]; /* fallthrough */
+		case 1:
+			obj[i++] = ring[idx++]; /* fallthrough */
+		}
+	} else {
+		for (i = 0; idx < size; i++, idx++)
+			obj[i] = ring[idx];
+		/* Start at the beginning */
+		for (idx = 0; i < n; i++, idx++)
+			obj[i] = ring[idx];
+	}
+}
+
+static __rte_always_inline void
+dequeue_elems_128(struct rte_ring *r, uint32_t prod_head,
+		void *obj_table, uint32_t n)
+{
+	unsigned int i;
+	const uint32_t size = r->size;
+	uint32_t idx = prod_head & r->mask;
+	rte_int128_t *ring = (rte_int128_t *)&r[1];
+	rte_int128_t *obj = (rte_int128_t *)obj_table;
+	if (likely(idx + n < size)) {
+		for (i = 0; i < (n & ~0x1); i += 2, idx += 2)
+			memcpy((void *)(obj + i), (void *)(ring + idx), 32);
+		switch (n & 0x1) {
+		case 1:
+			memcpy((void *)(obj + i), (void *)(ring + idx), 16);
+		}
+	} else {
+		for (i = 0; idx < size; i++, idx++)
+			memcpy((void *)(obj + i), (void *)(ring + idx), 16);
+		/* Start at the beginning */
+		for (idx = 0; i < n; i++, idx++)
+			memcpy((void *)(obj + i), (void *)(ring + idx), 16);
+	}
+}
+
+/* the actual dequeue of elements from the ring.
+ * Placed here since identical code needed in both
+ * single and multi producer enqueue functions.
+ */
+static __rte_always_inline void
+dequeue_elems(struct rte_ring *r, uint32_t cons_head, void *obj_table,
+		uint32_t esize, uint32_t num)
+{
+	/* 8B and 16B copies implemented individually to retain
+	 * the current performance.
+	 */
+	if (esize == 8)
+		dequeue_elems_64(r, cons_head, obj_table, num);
+	else if (esize == 16)
+		dequeue_elems_128(r, cons_head, obj_table, num);
+	else {
+		uint32_t idx, scale, nr_idx, nr_num, nr_size;
+
+		/* Normalize to uint32_t */
+		scale = esize / sizeof(uint32_t);
+		nr_num = num * scale;
+		idx = cons_head & r->mask;
+		nr_idx = idx * scale;
+		nr_size = r->size * scale;
+		dequeue_elems_32(r, nr_size, nr_idx, obj_table, nr_num);
+	}
+}
+
+/* Between load and load. there might be cpu reorder in weak model
+ * (powerpc/arm).
+ * There are 2 choices for the users
+ * 1.use rmb() memory barrier
+ * 2.use one-direction load_acquire/store_release barrier,defined by
+ * CONFIG_RTE_USE_C11_MEM_MODEL=y
+ * It depends on performance test results.
+ * By default, move common functions to rte_ring_generic.h
+ */
+#ifdef RTE_USE_C11_MEM_MODEL
+#include "rte_ring_c11_mem.h"
+#else
+#include "rte_ring_generic.h"
+#endif
+
+/**
+ * @internal Enqueue several objects on the ring
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @param n
+ *   The number of objects to add in the ring from the obj_table.
+ * @param behavior
+ *   RTE_RING_QUEUE_FIXED:    Enqueue a fixed number of items from a ring
+ *   RTE_RING_QUEUE_VARIABLE: Enqueue as many items as possible from ring
+ * @param is_sp
+ *   Indicates whether to use single producer or multi-producer head update
+ * @param free_space
+ *   returns the amount of space after the enqueue operation has finished
+ * @return
+ *   Actual number of objects enqueued.
+ *   If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
+ */
+static __rte_always_inline unsigned int
+__rte_ring_do_enqueue_elem(struct rte_ring *r, const void *obj_table,
+		unsigned int esize, unsigned int n,
+		enum rte_ring_queue_behavior behavior, unsigned int is_sp,
+		unsigned int *free_space)
+{
+	uint32_t prod_head, prod_next;
+	uint32_t free_entries;
+
+	n = __rte_ring_move_prod_head(r, is_sp, n, behavior,
+			&prod_head, &prod_next, &free_entries);
+	if (n == 0)
+		goto end;
+
+	enqueue_elems(r, prod_head, obj_table, esize, n);
+
+	update_tail(&r->prod, prod_head, prod_next, is_sp, 1);
+end:
+	if (free_space != NULL)
+		*free_space = free_entries - n;
+	return n;
+}
+
+/**
+ * @internal Dequeue several objects from the ring
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @param n
+ *   The number of objects to pull from the ring.
+ * @param behavior
+ *   RTE_RING_QUEUE_FIXED:    Dequeue a fixed number of items from a ring
+ *   RTE_RING_QUEUE_VARIABLE: Dequeue as many items as possible from ring
+ * @param is_sc
+ *   Indicates whether to use single consumer or multi-consumer head update
+ * @param available
+ *   returns the number of remaining ring entries after the dequeue has finished
+ * @return
+ *   - Actual number of objects dequeued.
+ *     If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
+ */
+static __rte_always_inline unsigned int
+__rte_ring_do_dequeue_elem(struct rte_ring *r, void *obj_table,
+		unsigned int esize, unsigned int n,
+		enum rte_ring_queue_behavior behavior, unsigned int is_sc,
+		unsigned int *available)
+{
+	uint32_t cons_head, cons_next;
+	uint32_t entries;
+
+	n = __rte_ring_move_cons_head(r, (int)is_sc, n, behavior,
+			&cons_head, &cons_next, &entries);
+	if (n == 0)
+		goto end;
+
+	dequeue_elems(r, cons_head, obj_table, esize, n);
+
+	update_tail(&r->cons, cons_head, cons_next, is_sc, 0);
+
+end:
+	if (available != NULL)
+		*available = entries - n;
+	return n;
+}
+
+/**
+ * Enqueue several objects on the ring (multi-producers safe).
+ *
+ * This function uses a "compare and set" instruction to move the
+ * producer index atomically.
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @param n
+ *   The number of objects to add in the ring from the obj_table.
+ * @param free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
+ * @return
+ *   The number of objects enqueued, either 0 or n
+ */
+static __rte_always_inline unsigned int
+rte_ring_mp_enqueue_bulk_elem(struct rte_ring *r, const void *obj_table,
+		unsigned int esize, unsigned int n, unsigned int *free_space)
+{
+	return __rte_ring_do_enqueue_elem(r, obj_table, esize, n,
+			RTE_RING_QUEUE_FIXED, __IS_MP, free_space);
+}
+
+/**
+ * Enqueue several objects on a ring
+ *
+ * @warning This API is NOT multi-producers safe
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @param n
+ *   The number of objects to add in the ring from the obj_table.
+ * @param free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
+ * @return
+ *   The number of objects enqueued, either 0 or n
+ */
+static __rte_always_inline unsigned int
+rte_ring_sp_enqueue_bulk_elem(struct rte_ring *r, const void *obj_table,
+		unsigned int esize, unsigned int n, unsigned int *free_space)
+{
+	return __rte_ring_do_enqueue_elem(r, obj_table, esize, n,
+			RTE_RING_QUEUE_FIXED, __IS_SP, free_space);
+}
+
+/**
+ * Enqueue several objects on a ring.
+ *
+ * This function calls the multi-producer or the single-producer
+ * version depending on the default behavior that was specified at
+ * ring creation time (see flags).
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @param n
+ *   The number of objects to add in the ring from the obj_table.
+ * @param free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
+ * @return
+ *   The number of objects enqueued, either 0 or n
+ */
+static __rte_always_inline unsigned int
+rte_ring_enqueue_bulk_elem(struct rte_ring *r, const void *obj_table,
+		unsigned int esize, unsigned int n, unsigned int *free_space)
+{
+	return __rte_ring_do_enqueue_elem(r, obj_table, esize, n,
+			RTE_RING_QUEUE_FIXED, r->prod.single, free_space);
+}
+
+/**
+ * Enqueue one object on a ring (multi-producers safe).
+ *
+ * This function uses a "compare and set" instruction to move the
+ * producer index atomically.
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj
+ *   A pointer to the object to be added.
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @return
+ *   - 0: Success; objects enqueued.
+ *   - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
+ */
+static __rte_always_inline int
+rte_ring_mp_enqueue_elem(struct rte_ring *r, void *obj, unsigned int esize)
+{
+	return rte_ring_mp_enqueue_bulk_elem(r, obj, esize, 1, NULL) ? 0 :
+								-ENOBUFS;
+}
+
+/**
+ * Enqueue one object on a ring
+ *
+ * @warning This API is NOT multi-producers safe
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj
+ *   A pointer to the object to be added.
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @return
+ *   - 0: Success; objects enqueued.
+ *   - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
+ */
+static __rte_always_inline int
+rte_ring_sp_enqueue_elem(struct rte_ring *r, void *obj, unsigned int esize)
+{
+	return rte_ring_sp_enqueue_bulk_elem(r, obj, esize, 1, NULL) ? 0 :
+								-ENOBUFS;
+}
+
+/**
+ * Enqueue one object on a ring.
+ *
+ * This function calls the multi-producer or the single-producer
+ * version, depending on the default behaviour that was specified at
+ * ring creation time (see flags).
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj
+ *   A pointer to the object to be added.
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @return
+ *   - 0: Success; objects enqueued.
+ *   - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
+ */
+static __rte_always_inline int
+rte_ring_enqueue_elem(struct rte_ring *r, void *obj, unsigned int esize)
+{
+	return rte_ring_enqueue_bulk_elem(r, obj, esize, 1, NULL) ? 0 :
+								-ENOBUFS;
+}
+
+/**
+ * Dequeue several objects from a ring (multi-consumers safe).
+ *
+ * This function uses a "compare and set" instruction to move the
+ * consumer index atomically.
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects) that will be filled.
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @param n
+ *   The number of objects to dequeue from the ring to the obj_table.
+ * @param available
+ *   If non-NULL, returns the number of remaining ring entries after the
+ *   dequeue has finished.
+ * @return
+ *   The number of objects dequeued, either 0 or n
+ */
+static __rte_always_inline unsigned int
+rte_ring_mc_dequeue_bulk_elem(struct rte_ring *r, void *obj_table,
+		unsigned int esize, unsigned int n, unsigned int *available)
+{
+	return __rte_ring_do_dequeue_elem(r, obj_table, esize, n,
+				RTE_RING_QUEUE_FIXED, __IS_MC, available);
+}
+
+/**
+ * Dequeue several objects from a ring (NOT multi-consumers safe).
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects) that will be filled.
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @param n
+ *   The number of objects to dequeue from the ring to the obj_table,
+ *   must be strictly positive.
+ * @param available
+ *   If non-NULL, returns the number of remaining ring entries after the
+ *   dequeue has finished.
+ * @return
+ *   The number of objects dequeued, either 0 or n
+ */
+static __rte_always_inline unsigned int
+rte_ring_sc_dequeue_bulk_elem(struct rte_ring *r, void *obj_table,
+		unsigned int esize, unsigned int n, unsigned int *available)
+{
+	return __rte_ring_do_dequeue_elem(r, obj_table, esize, n,
+			RTE_RING_QUEUE_FIXED, __IS_SC, available);
+}
+
+/**
+ * Dequeue several objects from a ring.
+ *
+ * This function calls the multi-consumers or the single-consumer
+ * version, depending on the default behaviour that was specified at
+ * ring creation time (see flags).
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects) that will be filled.
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @param n
+ *   The number of objects to dequeue from the ring to the obj_table.
+ * @param available
+ *   If non-NULL, returns the number of remaining ring entries after the
+ *   dequeue has finished.
+ * @return
+ *   The number of objects dequeued, either 0 or n
+ */
+static __rte_always_inline unsigned int
+rte_ring_dequeue_bulk_elem(struct rte_ring *r, void *obj_table,
+		unsigned int esize, unsigned int n, unsigned int *available)
+{
+	return __rte_ring_do_dequeue_elem(r, obj_table, esize, n,
+			RTE_RING_QUEUE_FIXED, r->cons.single, available);
+}
+
+/**
+ * Dequeue one object from a ring (multi-consumers safe).
+ *
+ * This function uses a "compare and set" instruction to move the
+ * consumer index atomically.
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_p
+ *   A pointer to a void * pointer (object) that will be filled.
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @return
+ *   - 0: Success; objects dequeued.
+ *   - -ENOENT: Not enough entries in the ring to dequeue; no object is
+ *     dequeued.
+ */
+static __rte_always_inline int
+rte_ring_mc_dequeue_elem(struct rte_ring *r, void *obj_p,
+				unsigned int esize)
+{
+	return rte_ring_mc_dequeue_bulk_elem(r, obj_p, esize, 1, NULL)  ? 0 :
+								-ENOENT;
+}
+
+/**
+ * Dequeue one object from a ring (NOT multi-consumers safe).
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_p
+ *   A pointer to a void * pointer (object) that will be filled.
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @return
+ *   - 0: Success; objects dequeued.
+ *   - -ENOENT: Not enough entries in the ring to dequeue, no object is
+ *     dequeued.
+ */
+static __rte_always_inline int
+rte_ring_sc_dequeue_elem(struct rte_ring *r, void *obj_p,
+				unsigned int esize)
+{
+	return rte_ring_sc_dequeue_bulk_elem(r, obj_p, esize, 1, NULL) ? 0 :
+								-ENOENT;
+}
+
+/**
+ * Dequeue one object from a ring.
+ *
+ * This function calls the multi-consumers or the single-consumer
+ * version depending on the default behaviour that was specified at
+ * ring creation time (see flags).
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_p
+ *   A pointer to a void * pointer (object) that will be filled.
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @return
+ *   - 0: Success, objects dequeued.
+ *   - -ENOENT: Not enough entries in the ring to dequeue, no object is
+ *     dequeued.
+ */
+static __rte_always_inline int
+rte_ring_dequeue_elem(struct rte_ring *r, void *obj_p, unsigned int esize)
+{
+	return rte_ring_dequeue_bulk_elem(r, obj_p, esize, 1, NULL) ? 0 :
+								-ENOENT;
+}
+
+/**
+ * Enqueue several objects on the ring (multi-producers safe).
+ *
+ * This function uses a "compare and set" instruction to move the
+ * producer index atomically.
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @param n
+ *   The number of objects to add in the ring from the obj_table.
+ * @param free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
+ * @return
+ *   - n: Actual number of objects enqueued.
+ */
+static __rte_always_inline unsigned
+rte_ring_mp_enqueue_burst_elem(struct rte_ring *r, const void *obj_table,
+		unsigned int esize, unsigned int n, unsigned int *free_space)
+{
+	return __rte_ring_do_enqueue_elem(r, obj_table, esize, n,
+			RTE_RING_QUEUE_VARIABLE, __IS_MP, free_space);
+}
+
+/**
+ * Enqueue several objects on a ring
+ *
+ * @warning This API is NOT multi-producers safe
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @param n
+ *   The number of objects to add in the ring from the obj_table.
+ * @param free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
+ * @return
+ *   - n: Actual number of objects enqueued.
+ */
+static __rte_always_inline unsigned
+rte_ring_sp_enqueue_burst_elem(struct rte_ring *r, const void *obj_table,
+		unsigned int esize, unsigned int n, unsigned int *free_space)
+{
+	return __rte_ring_do_enqueue_elem(r, obj_table, esize, n,
+			RTE_RING_QUEUE_VARIABLE, __IS_SP, free_space);
+}
+
+/**
+ * Enqueue several objects on a ring.
+ *
+ * This function calls the multi-producer or the single-producer
+ * version depending on the default behavior that was specified at
+ * ring creation time (see flags).
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects).
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @param n
+ *   The number of objects to add in the ring from the obj_table.
+ * @param free_space
+ *   if non-NULL, returns the amount of space in the ring after the
+ *   enqueue operation has finished.
+ * @return
+ *   - n: Actual number of objects enqueued.
+ */
+static __rte_always_inline unsigned
+rte_ring_enqueue_burst_elem(struct rte_ring *r, const void *obj_table,
+		unsigned int esize, unsigned int n, unsigned int *free_space)
+{
+	return __rte_ring_do_enqueue_elem(r, obj_table, esize, n,
+			RTE_RING_QUEUE_VARIABLE, r->prod.single, free_space);
+}
+
+/**
+ * Dequeue several objects from a ring (multi-consumers safe). When the request
+ * objects are more than the available objects, only dequeue the actual number
+ * of objects
+ *
+ * This function uses a "compare and set" instruction to move the
+ * consumer index atomically.
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects) that will be filled.
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @param n
+ *   The number of objects to dequeue from the ring to the obj_table.
+ * @param available
+ *   If non-NULL, returns the number of remaining ring entries after the
+ *   dequeue has finished.
+ * @return
+ *   - n: Actual number of objects dequeued, 0 if ring is empty
+ */
+static __rte_always_inline unsigned
+rte_ring_mc_dequeue_burst_elem(struct rte_ring *r, void *obj_table,
+		unsigned int esize, unsigned int n, unsigned int *available)
+{
+	return __rte_ring_do_dequeue_elem(r, obj_table, esize, n,
+			RTE_RING_QUEUE_VARIABLE, __IS_MC, available);
+}
+
+/**
+ * Dequeue several objects from a ring (NOT multi-consumers safe).When the
+ * request objects are more than the available objects, only dequeue the
+ * actual number of objects
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects) that will be filled.
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @param n
+ *   The number of objects to dequeue from the ring to the obj_table.
+ * @param available
+ *   If non-NULL, returns the number of remaining ring entries after the
+ *   dequeue has finished.
+ * @return
+ *   - n: Actual number of objects dequeued, 0 if ring is empty
+ */
+static __rte_always_inline unsigned
+rte_ring_sc_dequeue_burst_elem(struct rte_ring *r, void *obj_table,
+		unsigned int esize, unsigned int n, unsigned int *available)
+{
+	return __rte_ring_do_dequeue_elem(r, obj_table, esize, n,
+			RTE_RING_QUEUE_VARIABLE, __IS_SC, available);
+}
+
+/**
+ * Dequeue multiple objects from a ring up to a maximum number.
+ *
+ * This function calls the multi-consumers or the single-consumer
+ * version, depending on the default behaviour that was specified at
+ * ring creation time (see flags).
+ *
+ * @param r
+ *   A pointer to the ring structure.
+ * @param obj_table
+ *   A pointer to a table of void * pointers (objects) that will be filled.
+ * @param esize
+ *   The size of ring element, in bytes. It must be a multiple of 4.
+ *   This must be the same value used while creating the ring. Otherwise
+ *   the results are undefined.
+ * @param n
+ *   The number of objects to dequeue from the ring to the obj_table.
+ * @param available
+ *   If non-NULL, returns the number of remaining ring entries after the
+ *   dequeue has finished.
+ * @return
+ *   - Number of objects dequeued
+ */
+static __rte_always_inline unsigned int
+rte_ring_dequeue_burst_elem(struct rte_ring *r, void *obj_table,
+		unsigned int esize, unsigned int n, unsigned int *available)
+{
+	return __rte_ring_do_dequeue_elem(r, obj_table, esize, n,
+				RTE_RING_QUEUE_VARIABLE,
+				r->cons.single, available);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_RING_ELEM_H_ */
diff --git a/lib/librte_ring/rte_ring_version.map b/lib/librte_ring/rte_ring_version.map
index 89d84bcf4..7a5328dd5 100644
--- a/lib/librte_ring/rte_ring_version.map
+++ b/lib/librte_ring/rte_ring_version.map
@@ -15,6 +15,8 @@ DPDK_20.0 {
 EXPERIMENTAL {
 	global:
 
+	rte_ring_create_elem;
+	rte_ring_get_memsize_elem;
 	rte_ring_reset;
 
 };
-- 
2.17.1