4 * Copyright(c) 2010-2017 Intel Corporation. All rights reserved.
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35 * Derived from FreeBSD's bufring.h
37 **************************************************************************
39 * Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org
40 * All rights reserved.
42 * Redistribution and use in source and binary forms, with or without
43 * modification, are permitted provided that the following conditions are met:
45 * 1. Redistributions of source code must retain the above copyright notice,
46 * this list of conditions and the following disclaimer.
48 * 2. The name of Kip Macy nor the names of other
49 * contributors may be used to endorse or promote products derived from
50 * this software without specific prior written permission.
52 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
53 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
54 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
55 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
56 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
57 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
58 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
59 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
60 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
61 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
62 * POSSIBILITY OF SUCH DAMAGE.
64 ***************************************************************************/
73 * The Ring Manager is a fixed-size queue, implemented as a table of
74 * pointers. Head and tail pointers are modified atomically, allowing
75 * concurrent access to it. It has the following features:
77 * - FIFO (First In First Out)
78 * - Maximum size is fixed; the pointers are stored in a table.
79 * - Lockless implementation.
80 * - Multi- or single-consumer dequeue.
81 * - Multi- or single-producer enqueue.
85 * Note: the ring implementation is not preemptable. A lcore must not
86 * be interrupted by another task that uses the same ring.
96 #include <sys/queue.h>
98 #include <rte_common.h>
99 #include <rte_memory.h>
100 #include <rte_lcore.h>
101 #include <rte_atomic.h>
102 #include <rte_branch_prediction.h>
103 #include <rte_memzone.h>
105 #define RTE_TAILQ_RING_NAME "RTE_RING"
107 enum rte_ring_queue_behavior {
108 RTE_RING_QUEUE_FIXED = 0, /* Enq/Deq a fixed number of items from a ring */
109 RTE_RING_QUEUE_VARIABLE /* Enq/Deq as many items as possible from ring */
112 #define RTE_RING_MZ_PREFIX "RG_"
113 /**< The maximum length of a ring name. */
114 #define RTE_RING_NAMESIZE (RTE_MEMZONE_NAMESIZE - \
115 sizeof(RTE_RING_MZ_PREFIX) + 1)
117 struct rte_memzone; /* forward declaration, so as not to require memzone.h */
119 #if RTE_CACHE_LINE_SIZE < 128
120 #define PROD_ALIGN (RTE_CACHE_LINE_SIZE * 2)
121 #define CONS_ALIGN (RTE_CACHE_LINE_SIZE * 2)
123 #define PROD_ALIGN RTE_CACHE_LINE_SIZE
124 #define CONS_ALIGN RTE_CACHE_LINE_SIZE
127 /* structure to hold a pair of head/tail values and other metadata */
128 struct rte_ring_headtail {
129 volatile uint32_t head; /**< Prod/consumer head. */
130 volatile uint32_t tail; /**< Prod/consumer tail. */
131 uint32_t single; /**< True if single prod/cons */
135 * An RTE ring structure.
137 * The producer and the consumer have a head and a tail index. The particularity
138 * of these index is that they are not between 0 and size(ring). These indexes
139 * are between 0 and 2^32, and we mask their value when we access the ring[]
140 * field. Thanks to this assumption, we can do subtractions between 2 index
141 * values in a modulo-32bit base: that's why the overflow of the indexes is not
146 * Note: this field kept the RTE_MEMZONE_NAMESIZE size due to ABI
147 * compatibility requirements, it could be changed to RTE_RING_NAMESIZE
148 * next time the ABI changes
150 char name[RTE_MEMZONE_NAMESIZE]; /**< Name of the ring. */
151 int flags; /**< Flags supplied at creation. */
152 const struct rte_memzone *memzone;
153 /**< Memzone, if any, containing the rte_ring */
154 uint32_t size; /**< Size of ring. */
155 uint32_t mask; /**< Mask (size-1) of ring. */
157 /** Ring producer status. */
158 struct rte_ring_headtail prod __rte_aligned(PROD_ALIGN);
160 /** Ring consumer status. */
161 struct rte_ring_headtail cons __rte_aligned(CONS_ALIGN);
163 void *ring[] __rte_cache_aligned; /**< Memory space of ring starts here.
164 * not volatile so need to be careful
165 * about compiler re-ordering */
168 #define RING_F_SP_ENQ 0x0001 /**< The default enqueue is "single-producer". */
169 #define RING_F_SC_DEQ 0x0002 /**< The default dequeue is "single-consumer". */
170 #define RTE_RING_SZ_MASK (unsigned)(0x0fffffff) /**< Ring size mask */
173 * Calculate the memory size needed for a ring
175 * This function returns the number of bytes needed for a ring, given
176 * the number of elements in it. This value is the sum of the size of
177 * the structure rte_ring and the size of the memory needed by the
178 * objects pointers. The value is aligned to a cache line size.
181 * The number of elements in the ring (must be a power of 2).
183 * - The memory size needed for the ring on success.
184 * - -EINVAL if count is not a power of 2.
186 ssize_t rte_ring_get_memsize(unsigned count);
189 * Initialize a ring structure.
191 * Initialize a ring structure in memory pointed by "r". The size of the
192 * memory area must be large enough to store the ring structure and the
193 * object table. It is advised to use rte_ring_get_memsize() to get the
196 * The ring size is set to *count*, which must be a power of two. Water
197 * marking is disabled by default. The real usable ring size is
198 * *count-1* instead of *count* to differentiate a free ring from an
201 * The ring is not added in RTE_TAILQ_RING global list. Indeed, the
202 * memory given by the caller may not be shareable among dpdk
206 * The pointer to the ring structure followed by the objects table.
208 * The name of the ring.
210 * The number of elements in the ring (must be a power of 2).
212 * An OR of the following:
213 * - RING_F_SP_ENQ: If this flag is set, the default behavior when
214 * using ``rte_ring_enqueue()`` or ``rte_ring_enqueue_bulk()``
215 * is "single-producer". Otherwise, it is "multi-producers".
216 * - RING_F_SC_DEQ: If this flag is set, the default behavior when
217 * using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``
218 * is "single-consumer". Otherwise, it is "multi-consumers".
220 * 0 on success, or a negative value on error.
222 int rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
226 * Create a new ring named *name* in memory.
228 * This function uses ``memzone_reserve()`` to allocate memory. Then it
229 * calls rte_ring_init() to initialize an empty ring.
231 * The new ring size is set to *count*, which must be a power of
232 * two. Water marking is disabled by default. The real usable ring size
233 * is *count-1* instead of *count* to differentiate a free ring from an
236 * The ring is added in RTE_TAILQ_RING list.
239 * The name of the ring.
241 * The size of the ring (must be a power of 2).
243 * The *socket_id* argument is the socket identifier in case of
244 * NUMA. The value can be *SOCKET_ID_ANY* if there is no NUMA
245 * constraint for the reserved zone.
247 * An OR of the following:
248 * - RING_F_SP_ENQ: If this flag is set, the default behavior when
249 * using ``rte_ring_enqueue()`` or ``rte_ring_enqueue_bulk()``
250 * is "single-producer". Otherwise, it is "multi-producers".
251 * - RING_F_SC_DEQ: If this flag is set, the default behavior when
252 * using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``
253 * is "single-consumer". Otherwise, it is "multi-consumers".
255 * On success, the pointer to the new allocated ring. NULL on error with
256 * rte_errno set appropriately. Possible errno values include:
257 * - E_RTE_NO_CONFIG - function could not get pointer to rte_config structure
258 * - E_RTE_SECONDARY - function was called from a secondary process instance
259 * - EINVAL - count provided is not a power of 2
260 * - ENOSPC - the maximum number of memzones has already been allocated
261 * - EEXIST - a memzone with the same name already exists
262 * - ENOMEM - no appropriate memory area found in which to create memzone
264 struct rte_ring *rte_ring_create(const char *name, unsigned count,
265 int socket_id, unsigned flags);
267 * De-allocate all memory used by the ring.
272 void rte_ring_free(struct rte_ring *r);
275 * Dump the status of the ring to a file.
278 * A pointer to a file for output
280 * A pointer to the ring structure.
282 void rte_ring_dump(FILE *f, const struct rte_ring *r);
284 /* the actual enqueue of pointers on the ring.
285 * Placed here since identical code needed in both
286 * single and multi producer enqueue functions */
287 #define ENQUEUE_PTRS() do { \
288 const uint32_t size = r->size; \
289 uint32_t idx = prod_head & mask; \
290 if (likely(idx + n < size)) { \
291 for (i = 0; i < (n & ((~(unsigned)0x3))); i+=4, idx+=4) { \
292 r->ring[idx] = obj_table[i]; \
293 r->ring[idx+1] = obj_table[i+1]; \
294 r->ring[idx+2] = obj_table[i+2]; \
295 r->ring[idx+3] = obj_table[i+3]; \
298 case 3: r->ring[idx++] = obj_table[i++]; \
299 case 2: r->ring[idx++] = obj_table[i++]; \
300 case 1: r->ring[idx++] = obj_table[i++]; \
303 for (i = 0; idx < size; i++, idx++)\
304 r->ring[idx] = obj_table[i]; \
305 for (idx = 0; i < n; i++, idx++) \
306 r->ring[idx] = obj_table[i]; \
310 /* the actual copy of pointers on the ring to obj_table.
311 * Placed here since identical code needed in both
312 * single and multi consumer dequeue functions */
313 #define DEQUEUE_PTRS() do { \
314 uint32_t idx = cons_head & mask; \
315 const uint32_t size = r->size; \
316 if (likely(idx + n < size)) { \
317 for (i = 0; i < (n & (~(unsigned)0x3)); i+=4, idx+=4) {\
318 obj_table[i] = r->ring[idx]; \
319 obj_table[i+1] = r->ring[idx+1]; \
320 obj_table[i+2] = r->ring[idx+2]; \
321 obj_table[i+3] = r->ring[idx+3]; \
324 case 3: obj_table[i++] = r->ring[idx++]; \
325 case 2: obj_table[i++] = r->ring[idx++]; \
326 case 1: obj_table[i++] = r->ring[idx++]; \
329 for (i = 0; idx < size; i++, idx++) \
330 obj_table[i] = r->ring[idx]; \
331 for (idx = 0; i < n; i++, idx++) \
332 obj_table[i] = r->ring[idx]; \
337 * @internal Enqueue several objects on the ring (multi-producers safe).
339 * This function uses a "compare and set" instruction to move the
340 * producer index atomically.
343 * A pointer to the ring structure.
345 * A pointer to a table of void * pointers (objects).
347 * The number of objects to add in the ring from the obj_table.
349 * RTE_RING_QUEUE_FIXED: Enqueue a fixed number of items from a ring
350 * RTE_RING_QUEUE_VARIABLE: Enqueue as many items a possible from ring
352 * Depend on the behavior value
353 * if behavior = RTE_RING_QUEUE_FIXED
354 * - 0: Success; objects enqueue.
355 * - -ENOBUFS: Not enough room in the ring to enqueue, no object is enqueued.
356 * if behavior = RTE_RING_QUEUE_VARIABLE
357 * - n: Actual number of objects enqueued.
359 static inline int __attribute__((always_inline))
360 __rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
361 unsigned n, enum rte_ring_queue_behavior behavior)
363 uint32_t prod_head, prod_next;
364 uint32_t cons_tail, free_entries;
365 const unsigned max = n;
368 uint32_t mask = r->mask;
370 /* Avoid the unnecessary cmpset operation below, which is also
371 * potentially harmful when n equals 0. */
375 /* move prod.head atomically */
377 /* Reset n to the initial burst count */
380 prod_head = r->prod.head;
381 cons_tail = r->cons.tail;
382 /* The subtraction is done between two unsigned 32bits value
383 * (the result is always modulo 32 bits even if we have
384 * prod_head > cons_tail). So 'free_entries' is always between 0
385 * and size(ring)-1. */
386 free_entries = (mask + cons_tail - prod_head);
388 /* check that we have enough room in ring */
389 if (unlikely(n > free_entries)) {
390 if (behavior == RTE_RING_QUEUE_FIXED)
393 /* No free entry available */
394 if (unlikely(free_entries == 0))
400 prod_next = prod_head + n;
401 success = rte_atomic32_cmpset(&r->prod.head, prod_head,
403 } while (unlikely(success == 0));
405 /* write entries in ring */
410 * If there are other enqueues in progress that preceded us,
411 * we need to wait for them to complete
413 while (unlikely(r->prod.tail != prod_head))
416 r->prod.tail = prod_next;
417 return (behavior == RTE_RING_QUEUE_FIXED) ? 0 : n;
421 * @internal Enqueue several objects on a ring (NOT multi-producers safe).
424 * A pointer to the ring structure.
426 * A pointer to a table of void * pointers (objects).
428 * The number of objects to add in the ring from the obj_table.
430 * RTE_RING_QUEUE_FIXED: Enqueue a fixed number of items from a ring
431 * RTE_RING_QUEUE_VARIABLE: Enqueue as many items a possible from ring
433 * Depend on the behavior value
434 * if behavior = RTE_RING_QUEUE_FIXED
435 * - 0: Success; objects enqueue.
436 * - -ENOBUFS: Not enough room in the ring to enqueue, no object is enqueued.
437 * if behavior = RTE_RING_QUEUE_VARIABLE
438 * - n: Actual number of objects enqueued.
440 static inline int __attribute__((always_inline))
441 __rte_ring_sp_do_enqueue(struct rte_ring *r, void * const *obj_table,
442 unsigned n, enum rte_ring_queue_behavior behavior)
444 uint32_t prod_head, cons_tail;
445 uint32_t prod_next, free_entries;
447 uint32_t mask = r->mask;
449 prod_head = r->prod.head;
450 cons_tail = r->cons.tail;
451 /* The subtraction is done between two unsigned 32bits value
452 * (the result is always modulo 32 bits even if we have
453 * prod_head > cons_tail). So 'free_entries' is always between 0
454 * and size(ring)-1. */
455 free_entries = mask + cons_tail - prod_head;
457 /* check that we have enough room in ring */
458 if (unlikely(n > free_entries)) {
459 if (behavior == RTE_RING_QUEUE_FIXED)
462 /* No free entry available */
463 if (unlikely(free_entries == 0))
469 prod_next = prod_head + n;
470 r->prod.head = prod_next;
472 /* write entries in ring */
476 r->prod.tail = prod_next;
477 return (behavior == RTE_RING_QUEUE_FIXED) ? 0 : n;
481 * @internal Dequeue several objects from a ring (multi-consumers safe). When
482 * the request objects are more than the available objects, only dequeue the
483 * actual number of objects
485 * This function uses a "compare and set" instruction to move the
486 * consumer index atomically.
489 * A pointer to the ring structure.
491 * A pointer to a table of void * pointers (objects) that will be filled.
493 * The number of objects to dequeue from the ring to the obj_table.
495 * RTE_RING_QUEUE_FIXED: Dequeue a fixed number of items from a ring
496 * RTE_RING_QUEUE_VARIABLE: Dequeue as many items a possible from ring
498 * Depend on the behavior value
499 * if behavior = RTE_RING_QUEUE_FIXED
500 * - 0: Success; objects dequeued.
501 * - -ENOENT: Not enough entries in the ring to dequeue; no object is
503 * if behavior = RTE_RING_QUEUE_VARIABLE
504 * - n: Actual number of objects dequeued.
507 static inline int __attribute__((always_inline))
508 __rte_ring_mc_do_dequeue(struct rte_ring *r, void **obj_table,
509 unsigned n, enum rte_ring_queue_behavior behavior)
511 uint32_t cons_head, prod_tail;
512 uint32_t cons_next, entries;
513 const unsigned max = n;
516 uint32_t mask = r->mask;
518 /* Avoid the unnecessary cmpset operation below, which is also
519 * potentially harmful when n equals 0. */
523 /* move cons.head atomically */
525 /* Restore n as it may change every loop */
528 cons_head = r->cons.head;
529 prod_tail = r->prod.tail;
530 /* The subtraction is done between two unsigned 32bits value
531 * (the result is always modulo 32 bits even if we have
532 * cons_head > prod_tail). So 'entries' is always between 0
533 * and size(ring)-1. */
534 entries = (prod_tail - cons_head);
536 /* Set the actual entries for dequeue */
538 if (behavior == RTE_RING_QUEUE_FIXED)
541 if (unlikely(entries == 0))
547 cons_next = cons_head + n;
548 success = rte_atomic32_cmpset(&r->cons.head, cons_head,
550 } while (unlikely(success == 0));
557 * If there are other dequeues in progress that preceded us,
558 * we need to wait for them to complete
560 while (unlikely(r->cons.tail != cons_head))
563 r->cons.tail = cons_next;
565 return behavior == RTE_RING_QUEUE_FIXED ? 0 : n;
569 * @internal Dequeue several objects from a ring (NOT multi-consumers safe).
570 * When the request objects are more than the available objects, only dequeue
571 * the actual number of objects
574 * A pointer to the ring structure.
576 * A pointer to a table of void * pointers (objects) that will be filled.
578 * The number of objects to dequeue from the ring to the obj_table.
580 * RTE_RING_QUEUE_FIXED: Dequeue a fixed number of items from a ring
581 * RTE_RING_QUEUE_VARIABLE: Dequeue as many items a possible from ring
583 * Depend on the behavior value
584 * if behavior = RTE_RING_QUEUE_FIXED
585 * - 0: Success; objects dequeued.
586 * - -ENOENT: Not enough entries in the ring to dequeue; no object is
588 * if behavior = RTE_RING_QUEUE_VARIABLE
589 * - n: Actual number of objects dequeued.
591 static inline int __attribute__((always_inline))
592 __rte_ring_sc_do_dequeue(struct rte_ring *r, void **obj_table,
593 unsigned n, enum rte_ring_queue_behavior behavior)
595 uint32_t cons_head, prod_tail;
596 uint32_t cons_next, entries;
598 uint32_t mask = r->mask;
600 cons_head = r->cons.head;
601 prod_tail = r->prod.tail;
602 /* The subtraction is done between two unsigned 32bits value
603 * (the result is always modulo 32 bits even if we have
604 * cons_head > prod_tail). So 'entries' is always between 0
605 * and size(ring)-1. */
606 entries = prod_tail - cons_head;
609 if (behavior == RTE_RING_QUEUE_FIXED)
612 if (unlikely(entries == 0))
618 cons_next = cons_head + n;
619 r->cons.head = cons_next;
625 r->cons.tail = cons_next;
626 return behavior == RTE_RING_QUEUE_FIXED ? 0 : n;
630 * Enqueue several objects on the ring (multi-producers safe).
632 * This function uses a "compare and set" instruction to move the
633 * producer index atomically.
636 * A pointer to the ring structure.
638 * A pointer to a table of void * pointers (objects).
640 * The number of objects to add in the ring from the obj_table.
642 * - 0: Success; objects enqueue.
643 * - -ENOBUFS: Not enough room in the ring to enqueue, no object is enqueued.
645 static inline int __attribute__((always_inline))
646 rte_ring_mp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
649 return __rte_ring_mp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
653 * Enqueue several objects on a ring (NOT multi-producers safe).
656 * A pointer to the ring structure.
658 * A pointer to a table of void * pointers (objects).
660 * The number of objects to add in the ring from the obj_table.
662 * - 0: Success; objects enqueued.
663 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
665 static inline int __attribute__((always_inline))
666 rte_ring_sp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
669 return __rte_ring_sp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
673 * Enqueue several objects on a ring.
675 * This function calls the multi-producer or the single-producer
676 * version depending on the default behavior that was specified at
677 * ring creation time (see flags).
680 * A pointer to the ring structure.
682 * A pointer to a table of void * pointers (objects).
684 * The number of objects to add in the ring from the obj_table.
686 * - 0: Success; objects enqueued.
687 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
689 static inline int __attribute__((always_inline))
690 rte_ring_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
694 return rte_ring_sp_enqueue_bulk(r, obj_table, n);
696 return rte_ring_mp_enqueue_bulk(r, obj_table, n);
700 * Enqueue one object on a ring (multi-producers safe).
702 * This function uses a "compare and set" instruction to move the
703 * producer index atomically.
706 * A pointer to the ring structure.
708 * A pointer to the object to be added.
710 * - 0: Success; objects enqueued.
711 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
713 static inline int __attribute__((always_inline))
714 rte_ring_mp_enqueue(struct rte_ring *r, void *obj)
716 return rte_ring_mp_enqueue_bulk(r, &obj, 1);
720 * Enqueue one object on a ring (NOT multi-producers safe).
723 * A pointer to the ring structure.
725 * A pointer to the object to be added.
727 * - 0: Success; objects enqueued.
728 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
730 static inline int __attribute__((always_inline))
731 rte_ring_sp_enqueue(struct rte_ring *r, void *obj)
733 return rte_ring_sp_enqueue_bulk(r, &obj, 1);
737 * Enqueue one object on a ring.
739 * This function calls the multi-producer or the single-producer
740 * version, depending on the default behaviour that was specified at
741 * ring creation time (see flags).
744 * A pointer to the ring structure.
746 * A pointer to the object to be added.
748 * - 0: Success; objects enqueued.
749 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
751 static inline int __attribute__((always_inline))
752 rte_ring_enqueue(struct rte_ring *r, void *obj)
755 return rte_ring_sp_enqueue(r, obj);
757 return rte_ring_mp_enqueue(r, obj);
761 * Dequeue several objects from a ring (multi-consumers safe).
763 * This function uses a "compare and set" instruction to move the
764 * consumer index atomically.
767 * A pointer to the ring structure.
769 * A pointer to a table of void * pointers (objects) that will be filled.
771 * The number of objects to dequeue from the ring to the obj_table.
773 * - 0: Success; objects dequeued.
774 * - -ENOENT: Not enough entries in the ring to dequeue; no object is
777 static inline int __attribute__((always_inline))
778 rte_ring_mc_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
780 return __rte_ring_mc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
784 * Dequeue several objects from a ring (NOT multi-consumers safe).
787 * A pointer to the ring structure.
789 * A pointer to a table of void * pointers (objects) that will be filled.
791 * The number of objects to dequeue from the ring to the obj_table,
792 * must be strictly positive.
794 * - 0: Success; objects dequeued.
795 * - -ENOENT: Not enough entries in the ring to dequeue; no object is
798 static inline int __attribute__((always_inline))
799 rte_ring_sc_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
801 return __rte_ring_sc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
805 * Dequeue several objects from a ring.
807 * This function calls the multi-consumers or the single-consumer
808 * version, depending on the default behaviour that was specified at
809 * ring creation time (see flags).
812 * A pointer to the ring structure.
814 * A pointer to a table of void * pointers (objects) that will be filled.
816 * The number of objects to dequeue from the ring to the obj_table.
818 * - 0: Success; objects dequeued.
819 * - -ENOENT: Not enough entries in the ring to dequeue, no object is
822 static inline int __attribute__((always_inline))
823 rte_ring_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
826 return rte_ring_sc_dequeue_bulk(r, obj_table, n);
828 return rte_ring_mc_dequeue_bulk(r, obj_table, n);
832 * Dequeue one object from a ring (multi-consumers safe).
834 * This function uses a "compare and set" instruction to move the
835 * consumer index atomically.
838 * A pointer to the ring structure.
840 * A pointer to a void * pointer (object) that will be filled.
842 * - 0: Success; objects dequeued.
843 * - -ENOENT: Not enough entries in the ring to dequeue; no object is
846 static inline int __attribute__((always_inline))
847 rte_ring_mc_dequeue(struct rte_ring *r, void **obj_p)
849 return rte_ring_mc_dequeue_bulk(r, obj_p, 1);
853 * Dequeue one object from a ring (NOT multi-consumers safe).
856 * A pointer to the ring structure.
858 * A pointer to a void * pointer (object) that will be filled.
860 * - 0: Success; objects dequeued.
861 * - -ENOENT: Not enough entries in the ring to dequeue, no object is
864 static inline int __attribute__((always_inline))
865 rte_ring_sc_dequeue(struct rte_ring *r, void **obj_p)
867 return rte_ring_sc_dequeue_bulk(r, obj_p, 1);
871 * Dequeue one object from a ring.
873 * This function calls the multi-consumers or the single-consumer
874 * version depending on the default behaviour that was specified at
875 * ring creation time (see flags).
878 * A pointer to the ring structure.
880 * A pointer to a void * pointer (object) that will be filled.
882 * - 0: Success, objects dequeued.
883 * - -ENOENT: Not enough entries in the ring to dequeue, no object is
886 static inline int __attribute__((always_inline))
887 rte_ring_dequeue(struct rte_ring *r, void **obj_p)
890 return rte_ring_sc_dequeue(r, obj_p);
892 return rte_ring_mc_dequeue(r, obj_p);
896 * Test if a ring is full.
899 * A pointer to the ring structure.
901 * - 1: The ring is full.
902 * - 0: The ring is not full.
905 rte_ring_full(const struct rte_ring *r)
907 uint32_t prod_tail = r->prod.tail;
908 uint32_t cons_tail = r->cons.tail;
909 return ((cons_tail - prod_tail - 1) & r->mask) == 0;
913 * Test if a ring is empty.
916 * A pointer to the ring structure.
918 * - 1: The ring is empty.
919 * - 0: The ring is not empty.
922 rte_ring_empty(const struct rte_ring *r)
924 uint32_t prod_tail = r->prod.tail;
925 uint32_t cons_tail = r->cons.tail;
926 return !!(cons_tail == prod_tail);
930 * Return the number of entries in a ring.
933 * A pointer to the ring structure.
935 * The number of entries in the ring.
937 static inline unsigned
938 rte_ring_count(const struct rte_ring *r)
940 uint32_t prod_tail = r->prod.tail;
941 uint32_t cons_tail = r->cons.tail;
942 return (prod_tail - cons_tail) & r->mask;
946 * Return the number of free entries in a ring.
949 * A pointer to the ring structure.
951 * The number of free entries in the ring.
953 static inline unsigned
954 rte_ring_free_count(const struct rte_ring *r)
956 uint32_t prod_tail = r->prod.tail;
957 uint32_t cons_tail = r->cons.tail;
958 return (cons_tail - prod_tail - 1) & r->mask;
962 * Return the size of the ring.
965 * A pointer to the ring structure.
967 * The number of elements which can be stored in the ring.
969 static inline unsigned int
970 rte_ring_get_size(const struct rte_ring *r)
976 * Dump the status of all rings on the console
979 * A pointer to a file for output
981 void rte_ring_list_dump(FILE *f);
984 * Search a ring from its name
987 * The name of the ring.
989 * The pointer to the ring matching the name, or NULL if not found,
990 * with rte_errno set appropriately. Possible rte_errno values include:
991 * - ENOENT - required entry not available to return.
993 struct rte_ring *rte_ring_lookup(const char *name);
996 * Enqueue several objects on the ring (multi-producers safe).
998 * This function uses a "compare and set" instruction to move the
999 * producer index atomically.
1002 * A pointer to the ring structure.
1004 * A pointer to a table of void * pointers (objects).
1006 * The number of objects to add in the ring from the obj_table.
1008 * - n: Actual number of objects enqueued.
1010 static inline unsigned __attribute__((always_inline))
1011 rte_ring_mp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
1014 return __rte_ring_mp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
1018 * Enqueue several objects on a ring (NOT multi-producers safe).
1021 * A pointer to the ring structure.
1023 * A pointer to a table of void * pointers (objects).
1025 * The number of objects to add in the ring from the obj_table.
1027 * - n: Actual number of objects enqueued.
1029 static inline unsigned __attribute__((always_inline))
1030 rte_ring_sp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
1033 return __rte_ring_sp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
1037 * Enqueue several objects on a ring.
1039 * This function calls the multi-producer or the single-producer
1040 * version depending on the default behavior that was specified at
1041 * ring creation time (see flags).
1044 * A pointer to the ring structure.
1046 * A pointer to a table of void * pointers (objects).
1048 * The number of objects to add in the ring from the obj_table.
1050 * - n: Actual number of objects enqueued.
1052 static inline unsigned __attribute__((always_inline))
1053 rte_ring_enqueue_burst(struct rte_ring *r, void * const *obj_table,
1057 return rte_ring_sp_enqueue_burst(r, obj_table, n);
1059 return rte_ring_mp_enqueue_burst(r, obj_table, n);
1063 * Dequeue several objects from a ring (multi-consumers safe). When the request
1064 * objects are more than the available objects, only dequeue the actual number
1067 * This function uses a "compare and set" instruction to move the
1068 * consumer index atomically.
1071 * A pointer to the ring structure.
1073 * A pointer to a table of void * pointers (objects) that will be filled.
1075 * The number of objects to dequeue from the ring to the obj_table.
1077 * - n: Actual number of objects dequeued, 0 if ring is empty
1079 static inline unsigned __attribute__((always_inline))
1080 rte_ring_mc_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
1082 return __rte_ring_mc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
1086 * Dequeue several objects from a ring (NOT multi-consumers safe).When the
1087 * request objects are more than the available objects, only dequeue the
1088 * actual number of objects
1091 * A pointer to the ring structure.
1093 * A pointer to a table of void * pointers (objects) that will be filled.
1095 * The number of objects to dequeue from the ring to the obj_table.
1097 * - n: Actual number of objects dequeued, 0 if ring is empty
1099 static inline unsigned __attribute__((always_inline))
1100 rte_ring_sc_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
1102 return __rte_ring_sc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
1106 * Dequeue multiple objects from a ring up to a maximum number.
1108 * This function calls the multi-consumers or the single-consumer
1109 * version, depending on the default behaviour that was specified at
1110 * ring creation time (see flags).
1113 * A pointer to the ring structure.
1115 * A pointer to a table of void * pointers (objects) that will be filled.
1117 * The number of objects to dequeue from the ring to the obj_table.
1119 * - Number of objects dequeued
1121 static inline unsigned __attribute__((always_inline))
1122 rte_ring_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
1125 return rte_ring_sc_dequeue_burst(r, obj_table, n);
1127 return rte_ring_mc_dequeue_burst(r, obj_table, n);
1134 #endif /* _RTE_RING_H_ */