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authorC.J. Collier <cjcollier@linuxfoundation.org>2016-06-14 07:50:17 -0700
committerC.J. Collier <cjcollier@linuxfoundation.org>2016-06-14 12:17:54 -0700
commit97f17497d162afdb82c8704bf097f0fee3724b2e (patch)
tree1c6269614c0c15ffef8451c58ae8f8b30a1bc804 /lib/librte_ring/rte_ring.h
parente04be89c2409570e0055b2cda60bd11395bb93b0 (diff)
Imported Upstream version 16.04
Change-Id: I77eadcd8538a9122e4773cbe55b24033dc451757 Signed-off-by: C.J. Collier <cjcollier@linuxfoundation.org>
Diffstat (limited to 'lib/librte_ring/rte_ring.h')
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1 files changed, 1261 insertions, 0 deletions
diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
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@@ -0,0 +1,1261 @@
+/*-
+ * BSD LICENSE
+ *
+ * Copyright(c) 2010-2014 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.
+ */
+
+/*
+ * Derived from FreeBSD's bufring.h
+ *
+ **************************************************************************
+ *
+ * Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. The name of Kip Macy nor the names of other
+ * 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.
+ *
+ ***************************************************************************/
+
+#ifndef _RTE_RING_H_
+#define _RTE_RING_H_
+
+/**
+ * @file
+ * RTE Ring
+ *
+ * The Ring Manager is a fixed-size queue, implemented as a table of
+ * pointers. Head and tail pointers are modified atomically, allowing
+ * concurrent access to it. It has the following features:
+ *
+ * - FIFO (First In First Out)
+ * - Maximum size is fixed; the pointers are stored in a table.
+ * - Lockless implementation.
+ * - Multi- or single-consumer dequeue.
+ * - Multi- or single-producer enqueue.
+ * - Bulk dequeue.
+ * - Bulk enqueue.
+ *
+ * Note: the ring implementation is not preemptable. A lcore must not
+ * be interrupted by another task that uses the same ring.
+ *
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdio.h>
+#include <stdint.h>
+#include <sys/queue.h>
+#include <errno.h>
+#include <rte_common.h>
+#include <rte_memory.h>
+#include <rte_lcore.h>
+#include <rte_atomic.h>
+#include <rte_branch_prediction.h>
+
+#define RTE_TAILQ_RING_NAME "RTE_RING"
+
+enum rte_ring_queue_behavior {
+ RTE_RING_QUEUE_FIXED = 0, /* Enq/Deq a fixed number of items from a ring */
+ RTE_RING_QUEUE_VARIABLE /* Enq/Deq as many items a possible from ring */
+};
+
+#ifdef RTE_LIBRTE_RING_DEBUG
+/**
+ * A structure that stores the ring statistics (per-lcore).
+ */
+struct rte_ring_debug_stats {
+ uint64_t enq_success_bulk; /**< Successful enqueues number. */
+ uint64_t enq_success_objs; /**< Objects successfully enqueued. */
+ uint64_t enq_quota_bulk; /**< Successful enqueues above watermark. */
+ uint64_t enq_quota_objs; /**< Objects enqueued above watermark. */
+ uint64_t enq_fail_bulk; /**< Failed enqueues number. */
+ uint64_t enq_fail_objs; /**< Objects that failed to be enqueued. */
+ uint64_t deq_success_bulk; /**< Successful dequeues number. */
+ uint64_t deq_success_objs; /**< Objects successfully dequeued. */
+ uint64_t deq_fail_bulk; /**< Failed dequeues number. */
+ uint64_t deq_fail_objs; /**< Objects that failed to be dequeued. */
+} __rte_cache_aligned;
+#endif
+
+#define RTE_RING_NAMESIZE 32 /**< The maximum length of a ring name. */
+#define RTE_RING_MZ_PREFIX "RG_"
+
+#ifndef RTE_RING_PAUSE_REP_COUNT
+#define RTE_RING_PAUSE_REP_COUNT 0 /**< Yield after pause num of times, no yield
+ * if RTE_RING_PAUSE_REP not defined. */
+#endif
+
+struct rte_memzone; /* forward declaration, so as not to require memzone.h */
+
+/**
+ * An RTE ring structure.
+ *
+ * The producer and the consumer have a head and a tail index. The particularity
+ * of these index is that they are not between 0 and size(ring). These indexes
+ * are between 0 and 2^32, and we mask their value when we access the ring[]
+ * field. Thanks to this assumption, we can do subtractions between 2 index
+ * values in a modulo-32bit base: that's why the overflow of the indexes is not
+ * a problem.
+ */
+struct rte_ring {
+ char name[RTE_RING_NAMESIZE]; /**< Name of the ring. */
+ int flags; /**< Flags supplied at creation. */
+ const struct rte_memzone *memzone;
+ /**< Memzone, if any, containing the rte_ring */
+
+ /** Ring producer status. */
+ struct prod {
+ uint32_t watermark; /**< Maximum items before EDQUOT. */
+ uint32_t sp_enqueue; /**< True, if single producer. */
+ uint32_t size; /**< Size of ring. */
+ uint32_t mask; /**< Mask (size-1) of ring. */
+ volatile uint32_t head; /**< Producer head. */
+ volatile uint32_t tail; /**< Producer tail. */
+ } prod __rte_cache_aligned;
+
+ /** Ring consumer status. */
+ struct cons {
+ uint32_t sc_dequeue; /**< True, if single consumer. */
+ uint32_t size; /**< Size of the ring. */
+ uint32_t mask; /**< Mask (size-1) of ring. */
+ volatile uint32_t head; /**< Consumer head. */
+ volatile uint32_t tail; /**< Consumer tail. */
+#ifdef RTE_RING_SPLIT_PROD_CONS
+ } cons __rte_cache_aligned;
+#else
+ } cons;
+#endif
+
+#ifdef RTE_LIBRTE_RING_DEBUG
+ struct rte_ring_debug_stats stats[RTE_MAX_LCORE];
+#endif
+
+ void * ring[0] __rte_cache_aligned; /**< Memory space of ring starts here.
+ * not volatile so need to be careful
+ * about compiler re-ordering */
+};
+
+#define RING_F_SP_ENQ 0x0001 /**< The default enqueue is "single-producer". */
+#define RING_F_SC_DEQ 0x0002 /**< The default dequeue is "single-consumer". */
+#define RTE_RING_QUOT_EXCEED (1 << 31) /**< Quota exceed for burst ops */
+#define RTE_RING_SZ_MASK (unsigned)(0x0fffffff) /**< Ring size mask */
+
+/**
+ * @internal When debug is enabled, store ring statistics.
+ * @param r
+ * A pointer to the ring.
+ * @param name
+ * The name of the statistics field to increment in the ring.
+ * @param n
+ * The number to add to the object-oriented statistics.
+ */
+#ifdef RTE_LIBRTE_RING_DEBUG
+#define __RING_STAT_ADD(r, name, n) do { \
+ unsigned __lcore_id = rte_lcore_id(); \
+ if (__lcore_id < RTE_MAX_LCORE) { \
+ r->stats[__lcore_id].name##_objs += n; \
+ r->stats[__lcore_id].name##_bulk += 1; \
+ } \
+ } while(0)
+#else
+#define __RING_STAT_ADD(r, name, n) do {} while(0)
+#endif
+
+/**
+ * Calculate the memory size needed for a ring
+ *
+ * This function returns the number of bytes needed for a ring, given
+ * the number of elements in it. This value is the sum of the size of
+ * the structure rte_ring and the size of the memory needed by the
+ * objects pointers. The value is aligned to a cache line size.
+ *
+ * @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 if count is not a power of 2.
+ */
+ssize_t rte_ring_get_memsize(unsigned count);
+
+/**
+ * Initialize a ring structure.
+ *
+ * Initialize a ring structure in memory pointed by "r". The size of the
+ * memory area must be large enough to store the ring structure and the
+ * object table. It is advised to use rte_ring_get_memsize() to get the
+ * appropriate size.
+ *
+ * The 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 not added in RTE_TAILQ_RING global list. Indeed, the
+ * memory given by the caller may not be shareable among dpdk
+ * processes.
+ *
+ * @param r
+ * The pointer to the ring structure followed by the objects table.
+ * @param name
+ * The name of the ring.
+ * @param count
+ * The number of elements in the ring (must be a power of 2).
+ * @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
+ * 0 on success, or a negative value on error.
+ */
+int rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
+ unsigned flags);
+
+/**
+ * Create a new ring named *name* in memory.
+ *
+ * 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 count
+ * The size of 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 - 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
+ */
+struct rte_ring *rte_ring_create(const char *name, unsigned count,
+ int socket_id, unsigned flags);
+/**
+ * De-allocate all memory used by the ring.
+ *
+ * @param r
+ * Ring to free
+ */
+void rte_ring_free(struct rte_ring *r);
+
+/**
+ * Change the high water mark.
+ *
+ * If *count* is 0, water marking is disabled. Otherwise, it is set to the
+ * *count* value. The *count* value must be greater than 0 and less
+ * than the ring size.
+ *
+ * This function can be called at any time (not necessarily at
+ * initialization).
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @param count
+ * The new water mark value.
+ * @return
+ * - 0: Success; water mark changed.
+ * - -EINVAL: Invalid water mark value.
+ */
+int rte_ring_set_water_mark(struct rte_ring *r, unsigned count);
+
+/**
+ * Dump the status of the ring to the console.
+ *
+ * @param f
+ * A pointer to a file for output
+ * @param r
+ * A pointer to the ring structure.
+ */
+void rte_ring_dump(FILE *f, const struct rte_ring *r);
+
+/* the actual enqueue of pointers on the ring.
+ * Placed here since identical code needed in both
+ * single and multi producer enqueue functions */
+#define ENQUEUE_PTRS() do { \
+ const uint32_t size = r->prod.size; \
+ uint32_t idx = prod_head & mask; \
+ if (likely(idx + n < size)) { \
+ for (i = 0; i < (n & ((~(unsigned)0x3))); i+=4, idx+=4) { \
+ r->ring[idx] = obj_table[i]; \
+ r->ring[idx+1] = obj_table[i+1]; \
+ r->ring[idx+2] = obj_table[i+2]; \
+ r->ring[idx+3] = obj_table[i+3]; \
+ } \
+ switch (n & 0x3) { \
+ case 3: r->ring[idx++] = obj_table[i++]; \
+ case 2: r->ring[idx++] = obj_table[i++]; \
+ case 1: r->ring[idx++] = obj_table[i++]; \
+ } \
+ } else { \
+ for (i = 0; idx < size; i++, idx++)\
+ r->ring[idx] = obj_table[i]; \
+ for (idx = 0; i < n; i++, idx++) \
+ r->ring[idx] = obj_table[i]; \
+ } \
+} while(0)
+
+/* the actual copy of pointers on the ring to obj_table.
+ * Placed here since identical code needed in both
+ * single and multi consumer dequeue functions */
+#define DEQUEUE_PTRS() do { \
+ uint32_t idx = cons_head & mask; \
+ const uint32_t size = r->cons.size; \
+ if (likely(idx + n < size)) { \
+ for (i = 0; i < (n & (~(unsigned)0x3)); i+=4, idx+=4) {\
+ obj_table[i] = r->ring[idx]; \
+ obj_table[i+1] = r->ring[idx+1]; \
+ obj_table[i+2] = r->ring[idx+2]; \
+ obj_table[i+3] = r->ring[idx+3]; \
+ } \
+ switch (n & 0x3) { \
+ case 3: obj_table[i++] = r->ring[idx++]; \
+ case 2: obj_table[i++] = r->ring[idx++]; \
+ case 1: obj_table[i++] = r->ring[idx++]; \
+ } \
+ } else { \
+ for (i = 0; idx < size; i++, idx++) \
+ obj_table[i] = r->ring[idx]; \
+ for (idx = 0; i < n; i++, idx++) \
+ obj_table[i] = r->ring[idx]; \
+ } \
+} while (0)
+
+/**
+ * @internal 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 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 a possible from ring
+ * @return
+ * Depend on the behavior value
+ * if behavior = RTE_RING_QUEUE_FIXED
+ * - 0: Success; objects enqueue.
+ * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
+ * high water mark is exceeded.
+ * - -ENOBUFS: Not enough room in the ring to enqueue, no object is enqueued.
+ * if behavior = RTE_RING_QUEUE_VARIABLE
+ * - n: Actual number of objects enqueued.
+ */
+static inline int __attribute__((always_inline))
+__rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
+ unsigned n, enum rte_ring_queue_behavior behavior)
+{
+ uint32_t prod_head, prod_next;
+ uint32_t cons_tail, free_entries;
+ const unsigned max = n;
+ int success;
+ unsigned i, rep = 0;
+ uint32_t mask = r->prod.mask;
+ int ret;
+
+ /* Avoid the unnecessary cmpset operation below, which is also
+ * potentially harmful when n equals 0. */
+ if (n == 0)
+ return 0;
+
+ /* move prod.head atomically */
+ do {
+ /* Reset n to the initial burst count */
+ n = max;
+
+ prod_head = r->prod.head;
+ cons_tail = r->cons.tail;
+ /* The subtraction is done between two unsigned 32bits value
+ * (the result is always modulo 32 bits even if we have
+ * prod_head > cons_tail). So 'free_entries' is always between 0
+ * and size(ring)-1. */
+ free_entries = (mask + cons_tail - prod_head);
+
+ /* check that we have enough room in ring */
+ if (unlikely(n > free_entries)) {
+ if (behavior == RTE_RING_QUEUE_FIXED) {
+ __RING_STAT_ADD(r, enq_fail, n);
+ return -ENOBUFS;
+ }
+ else {
+ /* No free entry available */
+ if (unlikely(free_entries == 0)) {
+ __RING_STAT_ADD(r, enq_fail, n);
+ return 0;
+ }
+
+ n = free_entries;
+ }
+ }
+
+ prod_next = prod_head + n;
+ success = rte_atomic32_cmpset(&r->prod.head, prod_head,
+ prod_next);
+ } while (unlikely(success == 0));
+
+ /* write entries in ring */
+ ENQUEUE_PTRS();
+ rte_smp_wmb();
+
+ /* if we exceed the watermark */
+ if (unlikely(((mask + 1) - free_entries + n) > r->prod.watermark)) {
+ ret = (behavior == RTE_RING_QUEUE_FIXED) ? -EDQUOT :
+ (int)(n | RTE_RING_QUOT_EXCEED);
+ __RING_STAT_ADD(r, enq_quota, n);
+ }
+ else {
+ ret = (behavior == RTE_RING_QUEUE_FIXED) ? 0 : n;
+ __RING_STAT_ADD(r, enq_success, n);
+ }
+
+ /*
+ * If there are other enqueues in progress that preceded us,
+ * we need to wait for them to complete
+ */
+ while (unlikely(r->prod.tail != prod_head)) {
+ rte_pause();
+
+ /* Set RTE_RING_PAUSE_REP_COUNT to avoid spin too long waiting
+ * for other thread finish. It gives pre-empted thread a chance
+ * to proceed and finish with ring dequeue operation. */
+ if (RTE_RING_PAUSE_REP_COUNT &&
+ ++rep == RTE_RING_PAUSE_REP_COUNT) {
+ rep = 0;
+ sched_yield();
+ }
+ }
+ r->prod.tail = prod_next;
+ return ret;
+}
+
+/**
+ * @internal Enqueue several objects on a ring (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 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 a possible from ring
+ * @return
+ * Depend on the behavior value
+ * if behavior = RTE_RING_QUEUE_FIXED
+ * - 0: Success; objects enqueue.
+ * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
+ * high water mark is exceeded.
+ * - -ENOBUFS: Not enough room in the ring to enqueue, no object is enqueued.
+ * if behavior = RTE_RING_QUEUE_VARIABLE
+ * - n: Actual number of objects enqueued.
+ */
+static inline int __attribute__((always_inline))
+__rte_ring_sp_do_enqueue(struct rte_ring *r, void * const *obj_table,
+ unsigned n, enum rte_ring_queue_behavior behavior)
+{
+ uint32_t prod_head, cons_tail;
+ uint32_t prod_next, free_entries;
+ unsigned i;
+ uint32_t mask = r->prod.mask;
+ int ret;
+
+ prod_head = r->prod.head;
+ cons_tail = r->cons.tail;
+ /* The subtraction is done between two unsigned 32bits value
+ * (the result is always modulo 32 bits even if we have
+ * prod_head > cons_tail). So 'free_entries' is always between 0
+ * and size(ring)-1. */
+ free_entries = mask + cons_tail - prod_head;
+
+ /* check that we have enough room in ring */
+ if (unlikely(n > free_entries)) {
+ if (behavior == RTE_RING_QUEUE_FIXED) {
+ __RING_STAT_ADD(r, enq_fail, n);
+ return -ENOBUFS;
+ }
+ else {
+ /* No free entry available */
+ if (unlikely(free_entries == 0)) {
+ __RING_STAT_ADD(r, enq_fail, n);
+ return 0;
+ }
+
+ n = free_entries;
+ }
+ }
+
+ prod_next = prod_head + n;
+ r->prod.head = prod_next;
+
+ /* write entries in ring */
+ ENQUEUE_PTRS();
+ rte_smp_wmb();
+
+ /* if we exceed the watermark */
+ if (unlikely(((mask + 1) - free_entries + n) > r->prod.watermark)) {
+ ret = (behavior == RTE_RING_QUEUE_FIXED) ? -EDQUOT :
+ (int)(n | RTE_RING_QUOT_EXCEED);
+ __RING_STAT_ADD(r, enq_quota, n);
+ }
+ else {
+ ret = (behavior == RTE_RING_QUEUE_FIXED) ? 0 : n;
+ __RING_STAT_ADD(r, enq_success, n);
+ }
+
+ r->prod.tail = prod_next;
+ return ret;
+}
+
+/**
+ * @internal 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 n
+ * The number of objects to dequeue from the ring to the obj_table.
+ * @param behavior
+ * RTE_RING_QUEUE_FIXED: Dequeue a fixed number of items from a ring
+ * RTE_RING_QUEUE_VARIABLE: Dequeue as many items a possible from ring
+ * @return
+ * Depend on the behavior value
+ * if behavior = RTE_RING_QUEUE_FIXED
+ * - 0: Success; objects dequeued.
+ * - -ENOENT: Not enough entries in the ring to dequeue; no object is
+ * dequeued.
+ * if behavior = RTE_RING_QUEUE_VARIABLE
+ * - n: Actual number of objects dequeued.
+ */
+
+static inline int __attribute__((always_inline))
+__rte_ring_mc_do_dequeue(struct rte_ring *r, void **obj_table,
+ unsigned n, enum rte_ring_queue_behavior behavior)
+{
+ uint32_t cons_head, prod_tail;
+ uint32_t cons_next, entries;
+ const unsigned max = n;
+ int success;
+ unsigned i, rep = 0;
+ uint32_t mask = r->prod.mask;
+
+ /* Avoid the unnecessary cmpset operation below, which is also
+ * potentially harmful when n equals 0. */
+ if (n == 0)
+ return 0;
+
+ /* move cons.head atomically */
+ do {
+ /* Restore n as it may change every loop */
+ n = max;
+
+ cons_head = r->cons.head;
+ prod_tail = r->prod.tail;
+ /* The subtraction is done between two unsigned 32bits value
+ * (the result is always modulo 32 bits even if we have
+ * cons_head > prod_tail). So 'entries' is always between 0
+ * and size(ring)-1. */
+ entries = (prod_tail - cons_head);
+
+ /* Set the actual entries for dequeue */
+ if (n > entries) {
+ if (behavior == RTE_RING_QUEUE_FIXED) {
+ __RING_STAT_ADD(r, deq_fail, n);
+ return -ENOENT;
+ }
+ else {
+ if (unlikely(entries == 0)){
+ __RING_STAT_ADD(r, deq_fail, n);
+ return 0;
+ }
+
+ n = entries;
+ }
+ }
+
+ cons_next = cons_head + n;
+ success = rte_atomic32_cmpset(&r->cons.head, cons_head,
+ cons_next);
+ } while (unlikely(success == 0));
+
+ /* copy in table */
+ DEQUEUE_PTRS();
+ rte_smp_rmb();
+
+ /*
+ * If there are other dequeues in progress that preceded us,
+ * we need to wait for them to complete
+ */
+ while (unlikely(r->cons.tail != cons_head)) {
+ rte_pause();
+
+ /* Set RTE_RING_PAUSE_REP_COUNT to avoid spin too long waiting
+ * for other thread finish. It gives pre-empted thread a chance
+ * to proceed and finish with ring dequeue operation. */
+ if (RTE_RING_PAUSE_REP_COUNT &&
+ ++rep == RTE_RING_PAUSE_REP_COUNT) {
+ rep = 0;
+ sched_yield();
+ }
+ }
+ __RING_STAT_ADD(r, deq_success, n);
+ r->cons.tail = cons_next;
+
+ return behavior == RTE_RING_QUEUE_FIXED ? 0 : n;
+}
+
+/**
+ * @internal 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 n
+ * The number of objects to dequeue from the ring to the obj_table.
+ * @param behavior
+ * RTE_RING_QUEUE_FIXED: Dequeue a fixed number of items from a ring
+ * RTE_RING_QUEUE_VARIABLE: Dequeue as many items a possible from ring
+ * @return
+ * Depend on the behavior value
+ * if behavior = RTE_RING_QUEUE_FIXED
+ * - 0: Success; objects dequeued.
+ * - -ENOENT: Not enough entries in the ring to dequeue; no object is
+ * dequeued.
+ * if behavior = RTE_RING_QUEUE_VARIABLE
+ * - n: Actual number of objects dequeued.
+ */
+static inline int __attribute__((always_inline))
+__rte_ring_sc_do_dequeue(struct rte_ring *r, void **obj_table,
+ unsigned n, enum rte_ring_queue_behavior behavior)
+{
+ uint32_t cons_head, prod_tail;
+ uint32_t cons_next, entries;
+ unsigned i;
+ uint32_t mask = r->prod.mask;
+
+ cons_head = r->cons.head;
+ prod_tail = r->prod.tail;
+ /* The subtraction is done between two unsigned 32bits value
+ * (the result is always modulo 32 bits even if we have
+ * cons_head > prod_tail). So 'entries' is always between 0
+ * and size(ring)-1. */
+ entries = prod_tail - cons_head;
+
+ if (n > entries) {
+ if (behavior == RTE_RING_QUEUE_FIXED) {
+ __RING_STAT_ADD(r, deq_fail, n);
+ return -ENOENT;
+ }
+ else {
+ if (unlikely(entries == 0)){
+ __RING_STAT_ADD(r, deq_fail, n);
+ return 0;
+ }
+
+ n = entries;
+ }
+ }
+
+ cons_next = cons_head + n;
+ r->cons.head = cons_next;
+
+ /* copy in table */
+ DEQUEUE_PTRS();
+ rte_smp_rmb();
+
+ __RING_STAT_ADD(r, deq_success, n);
+ r->cons.tail = cons_next;
+ return behavior == RTE_RING_QUEUE_FIXED ? 0 : 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 n
+ * The number of objects to add in the ring from the obj_table.
+ * @return
+ * - 0: Success; objects enqueue.
+ * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
+ * high water mark is exceeded.
+ * - -ENOBUFS: Not enough room in the ring to enqueue, no object is enqueued.
+ */
+static inline int __attribute__((always_inline))
+rte_ring_mp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
+ unsigned n)
+{
+ return __rte_ring_mp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
+}
+
+/**
+ * Enqueue several objects on a ring (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 n
+ * The number of objects to add in the ring from the obj_table.
+ * @return
+ * - 0: Success; objects enqueued.
+ * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
+ * high water mark is exceeded.
+ * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
+ */
+static inline int __attribute__((always_inline))
+rte_ring_sp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
+ unsigned n)
+{
+ return __rte_ring_sp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
+}
+
+/**
+ * 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 n
+ * The number of objects to add in the ring from the obj_table.
+ * @return
+ * - 0: Success; objects enqueued.
+ * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
+ * high water mark is exceeded.
+ * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
+ */
+static inline int __attribute__((always_inline))
+rte_ring_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
+ unsigned n)
+{
+ if (r->prod.sp_enqueue)
+ return rte_ring_sp_enqueue_bulk(r, obj_table, n);
+ else
+ return rte_ring_mp_enqueue_bulk(r, obj_table, n);
+}
+
+/**
+ * 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.
+ * @return
+ * - 0: Success; objects enqueued.
+ * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
+ * high water mark is exceeded.
+ * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
+ */
+static inline int __attribute__((always_inline))
+rte_ring_mp_enqueue(struct rte_ring *r, void *obj)
+{
+ return rte_ring_mp_enqueue_bulk(r, &obj, 1);
+}
+
+/**
+ * Enqueue one object on a ring (NOT multi-producers safe).
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @param obj
+ * A pointer to the object to be added.
+ * @return
+ * - 0: Success; objects enqueued.
+ * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
+ * high water mark is exceeded.
+ * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
+ */
+static inline int __attribute__((always_inline))
+rte_ring_sp_enqueue(struct rte_ring *r, void *obj)
+{
+ return rte_ring_sp_enqueue_bulk(r, &obj, 1);
+}
+
+/**
+ * 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.
+ * @return
+ * - 0: Success; objects enqueued.
+ * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
+ * high water mark is exceeded.
+ * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
+ */
+static inline int __attribute__((always_inline))
+rte_ring_enqueue(struct rte_ring *r, void *obj)
+{
+ if (r->prod.sp_enqueue)
+ return rte_ring_sp_enqueue(r, obj);
+ else
+ return rte_ring_mp_enqueue(r, obj);
+}
+
+/**
+ * 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 n
+ * The number of objects to dequeue from the ring to the obj_table.
+ * @return
+ * - 0: Success; objects dequeued.
+ * - -ENOENT: Not enough entries in the ring to dequeue; no object is
+ * dequeued.
+ */
+static inline int __attribute__((always_inline))
+rte_ring_mc_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
+{
+ return __rte_ring_mc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
+}
+
+/**
+ * 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 n
+ * The number of objects to dequeue from the ring to the obj_table,
+ * must be strictly positive.
+ * @return
+ * - 0: Success; objects dequeued.
+ * - -ENOENT: Not enough entries in the ring to dequeue; no object is
+ * dequeued.
+ */
+static inline int __attribute__((always_inline))
+rte_ring_sc_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
+{
+ return __rte_ring_sc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
+}
+
+/**
+ * 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 n
+ * The number of objects to dequeue from the ring to the obj_table.
+ * @return
+ * - 0: Success; objects dequeued.
+ * - -ENOENT: Not enough entries in the ring to dequeue, no object is
+ * dequeued.
+ */
+static inline int __attribute__((always_inline))
+rte_ring_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
+{
+ if (r->cons.sc_dequeue)
+ return rte_ring_sc_dequeue_bulk(r, obj_table, n);
+ else
+ return rte_ring_mc_dequeue_bulk(r, obj_table, n);
+}
+
+/**
+ * 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.
+ * @return
+ * - 0: Success; objects dequeued.
+ * - -ENOENT: Not enough entries in the ring to dequeue; no object is
+ * dequeued.
+ */
+static inline int __attribute__((always_inline))
+rte_ring_mc_dequeue(struct rte_ring *r, void **obj_p)
+{
+ return rte_ring_mc_dequeue_bulk(r, obj_p, 1);
+}
+
+/**
+ * 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.
+ * @return
+ * - 0: Success; objects dequeued.
+ * - -ENOENT: Not enough entries in the ring to dequeue, no object is
+ * dequeued.
+ */
+static inline int __attribute__((always_inline))
+rte_ring_sc_dequeue(struct rte_ring *r, void **obj_p)
+{
+ return rte_ring_sc_dequeue_bulk(r, obj_p, 1);
+}
+
+/**
+ * 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.
+ * @return
+ * - 0: Success, objects dequeued.
+ * - -ENOENT: Not enough entries in the ring to dequeue, no object is
+ * dequeued.
+ */
+static inline int __attribute__((always_inline))
+rte_ring_dequeue(struct rte_ring *r, void **obj_p)
+{
+ if (r->cons.sc_dequeue)
+ return rte_ring_sc_dequeue(r, obj_p);
+ else
+ return rte_ring_mc_dequeue(r, obj_p);
+}
+
+/**
+ * Test if a ring is full.
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @return
+ * - 1: The ring is full.
+ * - 0: The ring is not full.
+ */
+static inline int
+rte_ring_full(const struct rte_ring *r)
+{
+ uint32_t prod_tail = r->prod.tail;
+ uint32_t cons_tail = r->cons.tail;
+ return ((cons_tail - prod_tail - 1) & r->prod.mask) == 0;
+}
+
+/**
+ * Test if a ring is empty.
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @return
+ * - 1: The ring is empty.
+ * - 0: The ring is not empty.
+ */
+static inline int
+rte_ring_empty(const struct rte_ring *r)
+{
+ uint32_t prod_tail = r->prod.tail;
+ uint32_t cons_tail = r->cons.tail;
+ return !!(cons_tail == prod_tail);
+}
+
+/**
+ * Return the number of entries in a ring.
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @return
+ * The number of entries in the ring.
+ */
+static inline unsigned
+rte_ring_count(const struct rte_ring *r)
+{
+ uint32_t prod_tail = r->prod.tail;
+ uint32_t cons_tail = r->cons.tail;
+ return (prod_tail - cons_tail) & r->prod.mask;
+}
+
+/**
+ * Return the number of free entries in a ring.
+ *
+ * @param r
+ * A pointer to the ring structure.
+ * @return
+ * The number of free entries in the ring.
+ */
+static inline unsigned
+rte_ring_free_count(const struct rte_ring *r)
+{
+ uint32_t prod_tail = r->prod.tail;
+ uint32_t cons_tail = r->cons.tail;
+ return (cons_tail - prod_tail - 1) & r->prod.mask;
+}
+
+/**
+ * Dump the status of all rings on the console
+ *
+ * @param f
+ * A pointer to a file for output
+ */
+void rte_ring_list_dump(FILE *f);
+
+/**
+ * Search a ring from its name
+ *
+ * @param name
+ * The name of the ring.
+ * @return
+ * The pointer to the ring matching the name, or NULL if not found,
+ * with rte_errno set appropriately. Possible rte_errno values include:
+ * - ENOENT - required entry not available to return.
+ */
+struct rte_ring *rte_ring_lookup(const char *name);
+
+/**
+ * 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 n
+ * The number of objects to add in the ring from the obj_table.
+ * @return
+ * - n: Actual number of objects enqueued.
+ */
+static inline unsigned __attribute__((always_inline))
+rte_ring_mp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
+ unsigned n)
+{
+ return __rte_ring_mp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
+}
+
+/**
+ * Enqueue several objects on a ring (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 n
+ * The number of objects to add in the ring from the obj_table.
+ * @return
+ * - n: Actual number of objects enqueued.
+ */
+static inline unsigned __attribute__((always_inline))
+rte_ring_sp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
+ unsigned n)
+{
+ return __rte_ring_sp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
+}
+
+/**
+ * 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 n
+ * The number of objects to add in the ring from the obj_table.
+ * @return
+ * - n: Actual number of objects enqueued.
+ */
+static inline unsigned __attribute__((always_inline))
+rte_ring_enqueue_burst(struct rte_ring *r, void * const *obj_table,
+ unsigned n)
+{
+ if (r->prod.sp_enqueue)
+ return rte_ring_sp_enqueue_burst(r, obj_table, n);
+ else
+ return rte_ring_mp_enqueue_burst(r, obj_table, n);
+}
+
+/**
+ * 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 n
+ * The number of objects to dequeue from the ring to the obj_table.
+ * @return
+ * - n: Actual number of objects dequeued, 0 if ring is empty
+ */
+static inline unsigned __attribute__((always_inline))
+rte_ring_mc_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
+{
+ return __rte_ring_mc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
+}
+
+/**
+ * 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 n
+ * The number of objects to dequeue from the ring to the obj_table.
+ * @return
+ * - n: Actual number of objects dequeued, 0 if ring is empty
+ */
+static inline unsigned __attribute__((always_inline))
+rte_ring_sc_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
+{
+ return __rte_ring_sc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
+}
+
+/**
+ * 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 n
+ * The number of objects to dequeue from the ring to the obj_table.
+ * @return
+ * - Number of objects dequeued
+ */
+static inline unsigned __attribute__((always_inline))
+rte_ring_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
+{
+ if (r->cons.sc_dequeue)
+ return rte_ring_sc_dequeue_burst(r, obj_table, n);
+ else
+ return rte_ring_mc_dequeue_burst(r, obj_table, n);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_RING_H_ */