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19 * from this software without specific prior written permission.
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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 { \
289 const uint32_t size = r->size; \
290 uint32_t idx = prod_head & mask; \
291 if (likely(idx + n < size)) { \
292 for (i = 0; i < (n & ((~(unsigned)0x3))); i+=4, idx+=4) { \
293 r->ring[idx] = obj_table[i]; \
294 r->ring[idx+1] = obj_table[i+1]; \
295 r->ring[idx+2] = obj_table[i+2]; \
296 r->ring[idx+3] = obj_table[i+3]; \
299 case 3: r->ring[idx++] = obj_table[i++]; \
300 case 2: r->ring[idx++] = obj_table[i++]; \
301 case 1: r->ring[idx++] = obj_table[i++]; \
304 for (i = 0; idx < size; i++, idx++)\
305 r->ring[idx] = obj_table[i]; \
306 for (idx = 0; i < n; i++, idx++) \
307 r->ring[idx] = obj_table[i]; \
311 /* the actual copy of pointers on the ring to obj_table.
312 * Placed here since identical code needed in both
313 * single and multi consumer dequeue functions */
314 #define DEQUEUE_PTRS() do { \
316 uint32_t idx = cons_head & mask; \
317 const uint32_t size = r->size; \
318 if (likely(idx + n < size)) { \
319 for (i = 0; i < (n & (~(unsigned)0x3)); i+=4, idx+=4) {\
320 obj_table[i] = r->ring[idx]; \
321 obj_table[i+1] = r->ring[idx+1]; \
322 obj_table[i+2] = r->ring[idx+2]; \
323 obj_table[i+3] = r->ring[idx+3]; \
326 case 3: obj_table[i++] = r->ring[idx++]; \
327 case 2: obj_table[i++] = r->ring[idx++]; \
328 case 1: obj_table[i++] = r->ring[idx++]; \
331 for (i = 0; idx < size; i++, idx++) \
332 obj_table[i] = r->ring[idx]; \
333 for (idx = 0; i < n; i++, idx++) \
334 obj_table[i] = r->ring[idx]; \
339 * @internal Enqueue several objects on the ring (multi-producers safe).
341 * This function uses a "compare and set" instruction to move the
342 * producer index atomically.
345 * A pointer to the ring structure.
347 * A pointer to a table of void * pointers (objects).
349 * The number of objects to add in the ring from the obj_table.
351 * RTE_RING_QUEUE_FIXED: Enqueue a fixed number of items from a ring
352 * RTE_RING_QUEUE_VARIABLE: Enqueue as many items a possible from ring
354 * Actual number of objects enqueued.
355 * If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
357 static inline unsigned int __attribute__((always_inline))
358 __rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
359 unsigned int n, enum rte_ring_queue_behavior behavior,
360 unsigned int *free_space)
362 uint32_t prod_head, prod_next;
363 uint32_t cons_tail, free_entries;
364 const unsigned int max = n;
366 uint32_t mask = r->mask;
368 /* move prod.head atomically */
370 /* Reset n to the initial burst count */
373 prod_head = r->prod.head;
374 cons_tail = r->cons.tail;
375 /* The subtraction is done between two unsigned 32bits value
376 * (the result is always modulo 32 bits even if we have
377 * prod_head > cons_tail). So 'free_entries' is always between 0
378 * and size(ring)-1. */
379 free_entries = (mask + cons_tail - prod_head);
381 /* check that we have enough room in ring */
382 if (unlikely(n > free_entries))
383 n = (behavior == RTE_RING_QUEUE_FIXED) ?
389 prod_next = prod_head + n;
390 success = rte_atomic32_cmpset(&r->prod.head, prod_head,
392 } while (unlikely(success == 0));
394 /* write entries in ring */
399 * If there are other enqueues in progress that preceded us,
400 * we need to wait for them to complete
402 while (unlikely(r->prod.tail != prod_head))
405 r->prod.tail = prod_next;
407 if (free_space != NULL)
408 *free_space = free_entries - n;
413 * @internal Enqueue several objects on a ring (NOT multi-producers safe).
416 * A pointer to the ring structure.
418 * A pointer to a table of void * pointers (objects).
420 * The number of objects to add in the ring from the obj_table.
422 * RTE_RING_QUEUE_FIXED: Enqueue a fixed number of items from a ring
423 * RTE_RING_QUEUE_VARIABLE: Enqueue as many items a possible from ring
425 * Actual number of objects enqueued.
426 * If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
428 static inline unsigned int __attribute__((always_inline))
429 __rte_ring_sp_do_enqueue(struct rte_ring *r, void * const *obj_table,
430 unsigned int n, enum rte_ring_queue_behavior behavior,
431 unsigned int *free_space)
433 uint32_t prod_head, cons_tail;
434 uint32_t prod_next, free_entries;
435 uint32_t mask = r->mask;
437 prod_head = r->prod.head;
438 cons_tail = r->cons.tail;
439 /* The subtraction is done between two unsigned 32bits value
440 * (the result is always modulo 32 bits even if we have
441 * prod_head > cons_tail). So 'free_entries' is always between 0
442 * and size(ring)-1. */
443 free_entries = mask + cons_tail - prod_head;
445 /* check that we have enough room in ring */
446 if (unlikely(n > free_entries))
447 n = (behavior == RTE_RING_QUEUE_FIXED) ? 0 : free_entries;
453 prod_next = prod_head + n;
454 r->prod.head = prod_next;
456 /* write entries in ring */
460 r->prod.tail = prod_next;
462 if (free_space != NULL)
463 *free_space = free_entries - n;
468 * @internal Dequeue several objects from a ring (multi-consumers safe). When
469 * the request objects are more than the available objects, only dequeue the
470 * actual number of objects
472 * This function uses a "compare and set" instruction to move the
473 * consumer index atomically.
476 * A pointer to the ring structure.
478 * A pointer to a table of void * pointers (objects) that will be filled.
480 * The number of objects to dequeue from the ring to the obj_table.
482 * RTE_RING_QUEUE_FIXED: Dequeue a fixed number of items from a ring
483 * RTE_RING_QUEUE_VARIABLE: Dequeue as many items a possible from ring
485 * - Actual number of objects dequeued.
486 * If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
489 static inline unsigned int __attribute__((always_inline))
490 __rte_ring_mc_do_dequeue(struct rte_ring *r, void **obj_table,
491 unsigned int n, enum rte_ring_queue_behavior behavior,
492 unsigned int *available)
494 uint32_t cons_head, prod_tail;
495 uint32_t cons_next, entries;
496 const unsigned max = n;
498 uint32_t mask = r->mask;
500 /* move cons.head atomically */
502 /* Restore n as it may change every loop */
505 cons_head = r->cons.head;
506 prod_tail = r->prod.tail;
507 /* The subtraction is done between two unsigned 32bits value
508 * (the result is always modulo 32 bits even if we have
509 * cons_head > prod_tail). So 'entries' is always between 0
510 * and size(ring)-1. */
511 entries = (prod_tail - cons_head);
513 /* Set the actual entries for dequeue */
515 n = (behavior == RTE_RING_QUEUE_FIXED) ? 0 : entries;
517 if (unlikely(n == 0))
520 cons_next = cons_head + n;
521 success = rte_atomic32_cmpset(&r->cons.head, cons_head,
523 } while (unlikely(success == 0));
530 * If there are other dequeues in progress that preceded us,
531 * we need to wait for them to complete
533 while (unlikely(r->cons.tail != cons_head))
536 r->cons.tail = cons_next;
538 if (available != NULL)
539 *available = entries - n;
544 * @internal Dequeue several objects from a ring (NOT multi-consumers safe).
545 * When the request objects are more than the available objects, only dequeue
546 * the actual number of objects
549 * A pointer to the ring structure.
551 * A pointer to a table of void * pointers (objects) that will be filled.
553 * The number of objects to dequeue from the ring to the obj_table.
555 * RTE_RING_QUEUE_FIXED: Dequeue a fixed number of items from a ring
556 * RTE_RING_QUEUE_VARIABLE: Dequeue as many items a possible from ring
558 * - Actual number of objects dequeued.
559 * If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
561 static inline unsigned int __attribute__((always_inline))
562 __rte_ring_sc_do_dequeue(struct rte_ring *r, void **obj_table,
563 unsigned int n, enum rte_ring_queue_behavior behavior,
564 unsigned int *available)
566 uint32_t cons_head, prod_tail;
567 uint32_t cons_next, entries;
568 uint32_t mask = r->mask;
570 cons_head = r->cons.head;
571 prod_tail = r->prod.tail;
572 /* The subtraction is done between two unsigned 32bits value
573 * (the result is always modulo 32 bits even if we have
574 * cons_head > prod_tail). So 'entries' is always between 0
575 * and size(ring)-1. */
576 entries = prod_tail - cons_head;
579 n = (behavior == RTE_RING_QUEUE_FIXED) ? 0 : entries;
581 if (unlikely(entries == 0))
584 cons_next = cons_head + n;
585 r->cons.head = cons_next;
591 r->cons.tail = cons_next;
593 if (available != NULL)
594 *available = entries - n;
599 * Enqueue several objects on the ring (multi-producers safe).
601 * This function uses a "compare and set" instruction to move the
602 * producer index atomically.
605 * A pointer to the ring structure.
607 * A pointer to a table of void * pointers (objects).
609 * The number of objects to add in the ring from the obj_table.
611 * if non-NULL, returns the amount of space in the ring after the
612 * enqueue operation has finished.
614 * The number of objects enqueued, either 0 or n
616 static inline unsigned int __attribute__((always_inline))
617 rte_ring_mp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
618 unsigned int n, unsigned int *free_space)
620 return __rte_ring_mp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
625 * Enqueue several objects on a ring (NOT multi-producers safe).
628 * A pointer to the ring structure.
630 * A pointer to a table of void * pointers (objects).
632 * The number of objects to add in the ring from the obj_table.
634 * if non-NULL, returns the amount of space in the ring after the
635 * enqueue operation has finished.
637 * The number of objects enqueued, either 0 or n
639 static inline unsigned int __attribute__((always_inline))
640 rte_ring_sp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
641 unsigned int n, unsigned int *free_space)
643 return __rte_ring_sp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
648 * Enqueue several objects on a ring.
650 * This function calls the multi-producer or the single-producer
651 * version depending on the default behavior that was specified at
652 * ring creation time (see flags).
655 * A pointer to the ring structure.
657 * A pointer to a table of void * pointers (objects).
659 * The number of objects to add in the ring from the obj_table.
661 * if non-NULL, returns the amount of space in the ring after the
662 * enqueue operation has finished.
664 * The number of objects enqueued, either 0 or n
666 static inline unsigned int __attribute__((always_inline))
667 rte_ring_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
668 unsigned int n, unsigned int *free_space)
671 return rte_ring_sp_enqueue_bulk(r, obj_table, n, free_space);
673 return rte_ring_mp_enqueue_bulk(r, obj_table, n, free_space);
677 * Enqueue one object on a ring (multi-producers safe).
679 * This function uses a "compare and set" instruction to move the
680 * producer index atomically.
683 * A pointer to the ring structure.
685 * A pointer to the object to be added.
687 * - 0: Success; objects enqueued.
688 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
690 static inline int __attribute__((always_inline))
691 rte_ring_mp_enqueue(struct rte_ring *r, void *obj)
693 return rte_ring_mp_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
697 * Enqueue one object on a ring (NOT multi-producers safe).
700 * A pointer to the ring structure.
702 * A pointer to the object to be added.
704 * - 0: Success; objects enqueued.
705 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
707 static inline int __attribute__((always_inline))
708 rte_ring_sp_enqueue(struct rte_ring *r, void *obj)
710 return rte_ring_sp_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
714 * Enqueue one object on a ring.
716 * This function calls the multi-producer or the single-producer
717 * version, depending on the default behaviour that was specified at
718 * ring creation time (see flags).
721 * A pointer to the ring structure.
723 * A pointer to the object to be added.
725 * - 0: Success; objects enqueued.
726 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
728 static inline int __attribute__((always_inline))
729 rte_ring_enqueue(struct rte_ring *r, void *obj)
731 return rte_ring_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
735 * Dequeue several objects from a ring (multi-consumers safe).
737 * This function uses a "compare and set" instruction to move the
738 * consumer index atomically.
741 * A pointer to the ring structure.
743 * A pointer to a table of void * pointers (objects) that will be filled.
745 * The number of objects to dequeue from the ring to the obj_table.
747 * If non-NULL, returns the number of remaining ring entries after the
748 * dequeue has finished.
750 * The number of objects dequeued, either 0 or n
752 static inline unsigned int __attribute__((always_inline))
753 rte_ring_mc_dequeue_bulk(struct rte_ring *r, void **obj_table,
754 unsigned int n, unsigned int *available)
756 return __rte_ring_mc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
761 * Dequeue several objects from a ring (NOT multi-consumers safe).
764 * A pointer to the ring structure.
766 * A pointer to a table of void * pointers (objects) that will be filled.
768 * The number of objects to dequeue from the ring to the obj_table,
769 * must be strictly positive.
771 * If non-NULL, returns the number of remaining ring entries after the
772 * dequeue has finished.
774 * The number of objects dequeued, either 0 or n
776 static inline unsigned int __attribute__((always_inline))
777 rte_ring_sc_dequeue_bulk(struct rte_ring *r, void **obj_table,
778 unsigned int n, unsigned int *available)
780 return __rte_ring_sc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
785 * Dequeue several objects from a ring.
787 * This function calls the multi-consumers or the single-consumer
788 * version, depending on the default behaviour that was specified at
789 * ring creation time (see flags).
792 * A pointer to the ring structure.
794 * A pointer to a table of void * pointers (objects) that will be filled.
796 * The number of objects to dequeue from the ring to the obj_table.
798 * If non-NULL, returns the number of remaining ring entries after the
799 * dequeue has finished.
801 * The number of objects dequeued, either 0 or n
803 static inline unsigned int __attribute__((always_inline))
804 rte_ring_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned int n,
805 unsigned int *available)
808 return rte_ring_sc_dequeue_bulk(r, obj_table, n, available);
810 return rte_ring_mc_dequeue_bulk(r, obj_table, n, available);
814 * Dequeue one object from a ring (multi-consumers safe).
816 * This function uses a "compare and set" instruction to move the
817 * consumer index atomically.
820 * A pointer to the ring structure.
822 * A pointer to a void * pointer (object) that will be filled.
824 * - 0: Success; objects dequeued.
825 * - -ENOENT: Not enough entries in the ring to dequeue; no object is
828 static inline int __attribute__((always_inline))
829 rte_ring_mc_dequeue(struct rte_ring *r, void **obj_p)
831 return rte_ring_mc_dequeue_bulk(r, obj_p, 1, NULL) ? 0 : -ENOBUFS;
835 * Dequeue one object from a ring (NOT multi-consumers safe).
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_sc_dequeue(struct rte_ring *r, void **obj_p)
849 return rte_ring_sc_dequeue_bulk(r, obj_p, 1, NULL) ? 0 : -ENOBUFS;
853 * Dequeue one object from a ring.
855 * This function calls the multi-consumers or the single-consumer
856 * version depending on the default behaviour that was specified at
857 * ring creation time (see flags).
860 * A pointer to the ring structure.
862 * A pointer to a void * pointer (object) that will be filled.
864 * - 0: Success, objects dequeued.
865 * - -ENOENT: Not enough entries in the ring to dequeue, no object is
868 static inline int __attribute__((always_inline))
869 rte_ring_dequeue(struct rte_ring *r, void **obj_p)
871 return rte_ring_dequeue_bulk(r, obj_p, 1, NULL) ? 0 : -ENOBUFS;
875 * Test if a ring is full.
878 * A pointer to the ring structure.
880 * - 1: The ring is full.
881 * - 0: The ring is not full.
884 rte_ring_full(const struct rte_ring *r)
886 uint32_t prod_tail = r->prod.tail;
887 uint32_t cons_tail = r->cons.tail;
888 return ((cons_tail - prod_tail - 1) & r->mask) == 0;
892 * Test if a ring is empty.
895 * A pointer to the ring structure.
897 * - 1: The ring is empty.
898 * - 0: The ring is not empty.
901 rte_ring_empty(const struct rte_ring *r)
903 uint32_t prod_tail = r->prod.tail;
904 uint32_t cons_tail = r->cons.tail;
905 return !!(cons_tail == prod_tail);
909 * Return the number of entries in a ring.
912 * A pointer to the ring structure.
914 * The number of entries in the ring.
916 static inline unsigned
917 rte_ring_count(const struct rte_ring *r)
919 uint32_t prod_tail = r->prod.tail;
920 uint32_t cons_tail = r->cons.tail;
921 return (prod_tail - cons_tail) & r->mask;
925 * Return the number of free entries in a ring.
928 * A pointer to the ring structure.
930 * The number of free entries in the ring.
932 static inline unsigned
933 rte_ring_free_count(const struct rte_ring *r)
935 uint32_t prod_tail = r->prod.tail;
936 uint32_t cons_tail = r->cons.tail;
937 return (cons_tail - prod_tail - 1) & r->mask;
941 * Return the size of the ring.
944 * A pointer to the ring structure.
946 * The number of elements which can be stored in the ring.
948 static inline unsigned int
949 rte_ring_get_size(const struct rte_ring *r)
955 * Dump the status of all rings on the console
958 * A pointer to a file for output
960 void rte_ring_list_dump(FILE *f);
963 * Search a ring from its name
966 * The name of the ring.
968 * The pointer to the ring matching the name, or NULL if not found,
969 * with rte_errno set appropriately. Possible rte_errno values include:
970 * - ENOENT - required entry not available to return.
972 struct rte_ring *rte_ring_lookup(const char *name);
975 * Enqueue several objects on the ring (multi-producers safe).
977 * This function uses a "compare and set" instruction to move the
978 * producer index atomically.
981 * A pointer to the ring structure.
983 * A pointer to a table of void * pointers (objects).
985 * The number of objects to add in the ring from the obj_table.
987 * if non-NULL, returns the amount of space in the ring after the
988 * enqueue operation has finished.
990 * - n: Actual number of objects enqueued.
992 static inline unsigned __attribute__((always_inline))
993 rte_ring_mp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
994 unsigned int n, unsigned int *free_space)
996 return __rte_ring_mp_do_enqueue(r, obj_table, n,
997 RTE_RING_QUEUE_VARIABLE, free_space);
1001 * Enqueue several objects on a ring (NOT multi-producers safe).
1004 * A pointer to the ring structure.
1006 * A pointer to a table of void * pointers (objects).
1008 * The number of objects to add in the ring from the obj_table.
1010 * if non-NULL, returns the amount of space in the ring after the
1011 * enqueue operation has finished.
1013 * - n: Actual number of objects enqueued.
1015 static inline unsigned __attribute__((always_inline))
1016 rte_ring_sp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
1017 unsigned int n, unsigned int *free_space)
1019 return __rte_ring_sp_do_enqueue(r, obj_table, n,
1020 RTE_RING_QUEUE_VARIABLE, free_space);
1024 * Enqueue several objects on a ring.
1026 * This function calls the multi-producer or the single-producer
1027 * version depending on the default behavior that was specified at
1028 * ring creation time (see flags).
1031 * A pointer to the ring structure.
1033 * A pointer to a table of void * pointers (objects).
1035 * The number of objects to add in the ring from the obj_table.
1037 * if non-NULL, returns the amount of space in the ring after the
1038 * enqueue operation has finished.
1040 * - n: Actual number of objects enqueued.
1042 static inline unsigned __attribute__((always_inline))
1043 rte_ring_enqueue_burst(struct rte_ring *r, void * const *obj_table,
1044 unsigned int n, unsigned int *free_space)
1047 return rte_ring_sp_enqueue_burst(r, obj_table, n, free_space);
1049 return rte_ring_mp_enqueue_burst(r, obj_table, n, free_space);
1053 * Dequeue several objects from a ring (multi-consumers safe). When the request
1054 * objects are more than the available objects, only dequeue the actual number
1057 * This function uses a "compare and set" instruction to move the
1058 * consumer index atomically.
1061 * A pointer to the ring structure.
1063 * A pointer to a table of void * pointers (objects) that will be filled.
1065 * The number of objects to dequeue from the ring to the obj_table.
1067 * If non-NULL, returns the number of remaining ring entries after the
1068 * dequeue has finished.
1070 * - n: Actual number of objects dequeued, 0 if ring is empty
1072 static inline unsigned __attribute__((always_inline))
1073 rte_ring_mc_dequeue_burst(struct rte_ring *r, void **obj_table,
1074 unsigned int n, unsigned int *available)
1076 return __rte_ring_mc_do_dequeue(r, obj_table, n,
1077 RTE_RING_QUEUE_VARIABLE, available);
1081 * Dequeue several objects from a ring (NOT multi-consumers safe).When the
1082 * request objects are more than the available objects, only dequeue the
1083 * actual number of objects
1086 * A pointer to the ring structure.
1088 * A pointer to a table of void * pointers (objects) that will be filled.
1090 * The number of objects to dequeue from the ring to the obj_table.
1092 * If non-NULL, returns the number of remaining ring entries after the
1093 * dequeue has finished.
1095 * - n: Actual number of objects dequeued, 0 if ring is empty
1097 static inline unsigned __attribute__((always_inline))
1098 rte_ring_sc_dequeue_burst(struct rte_ring *r, void **obj_table,
1099 unsigned int n, unsigned int *available)
1101 return __rte_ring_sc_do_dequeue(r, obj_table, n,
1102 RTE_RING_QUEUE_VARIABLE, available);
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 * If non-NULL, returns the number of remaining ring entries after the
1120 * dequeue has finished.
1122 * - Number of objects dequeued
1124 static inline unsigned __attribute__((always_inline))
1125 rte_ring_dequeue_burst(struct rte_ring *r, void **obj_table,
1126 unsigned int n, unsigned int *available)
1129 return rte_ring_sc_dequeue_burst(r, obj_table, n, available);
1131 return rte_ring_mc_dequeue_burst(r, obj_table, n, available);
1138 #endif /* _RTE_RING_H_ */