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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 * Actual number of objects enqueued.
353 * If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
355 static inline unsigned int __attribute__((always_inline))
356 __rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
357 unsigned n, enum rte_ring_queue_behavior behavior)
359 uint32_t prod_head, prod_next;
360 uint32_t cons_tail, free_entries;
361 const unsigned max = n;
364 uint32_t mask = r->mask;
366 /* Avoid the unnecessary cmpset operation below, which is also
367 * potentially harmful when n equals 0. */
371 /* move prod.head atomically */
373 /* Reset n to the initial burst count */
376 prod_head = r->prod.head;
377 cons_tail = r->cons.tail;
378 /* The subtraction is done between two unsigned 32bits value
379 * (the result is always modulo 32 bits even if we have
380 * prod_head > cons_tail). So 'free_entries' is always between 0
381 * and size(ring)-1. */
382 free_entries = (mask + cons_tail - prod_head);
384 /* check that we have enough room in ring */
385 if (unlikely(n > free_entries)) {
386 if (behavior == RTE_RING_QUEUE_FIXED)
389 /* No free entry available */
390 if (unlikely(free_entries == 0))
396 prod_next = prod_head + n;
397 success = rte_atomic32_cmpset(&r->prod.head, prod_head,
399 } while (unlikely(success == 0));
401 /* write entries in ring */
406 * If there are other enqueues in progress that preceded us,
407 * we need to wait for them to complete
409 while (unlikely(r->prod.tail != prod_head))
412 r->prod.tail = prod_next;
417 * @internal Enqueue several objects on a ring (NOT multi-producers safe).
420 * A pointer to the ring structure.
422 * A pointer to a table of void * pointers (objects).
424 * The number of objects to add in the ring from the obj_table.
426 * RTE_RING_QUEUE_FIXED: Enqueue a fixed number of items from a ring
427 * RTE_RING_QUEUE_VARIABLE: Enqueue as many items a possible from ring
429 * Actual number of objects enqueued.
430 * If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
432 static inline unsigned int __attribute__((always_inline))
433 __rte_ring_sp_do_enqueue(struct rte_ring *r, void * const *obj_table,
434 unsigned n, enum rte_ring_queue_behavior behavior)
436 uint32_t prod_head, cons_tail;
437 uint32_t prod_next, free_entries;
439 uint32_t mask = r->mask;
441 prod_head = r->prod.head;
442 cons_tail = r->cons.tail;
443 /* The subtraction is done between two unsigned 32bits value
444 * (the result is always modulo 32 bits even if we have
445 * prod_head > cons_tail). So 'free_entries' is always between 0
446 * and size(ring)-1. */
447 free_entries = mask + cons_tail - prod_head;
449 /* check that we have enough room in ring */
450 if (unlikely(n > free_entries)) {
451 if (behavior == RTE_RING_QUEUE_FIXED)
454 /* No free entry available */
455 if (unlikely(free_entries == 0))
461 prod_next = prod_head + n;
462 r->prod.head = prod_next;
464 /* write entries in ring */
468 r->prod.tail = prod_next;
473 * @internal Dequeue several objects from a ring (multi-consumers safe). When
474 * the request objects are more than the available objects, only dequeue the
475 * actual number of objects
477 * This function uses a "compare and set" instruction to move the
478 * consumer index atomically.
481 * A pointer to the ring structure.
483 * A pointer to a table of void * pointers (objects) that will be filled.
485 * The number of objects to dequeue from the ring to the obj_table.
487 * RTE_RING_QUEUE_FIXED: Dequeue a fixed number of items from a ring
488 * RTE_RING_QUEUE_VARIABLE: Dequeue as many items a possible from ring
490 * - Actual number of objects dequeued.
491 * If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
494 static inline unsigned int __attribute__((always_inline))
495 __rte_ring_mc_do_dequeue(struct rte_ring *r, void **obj_table,
496 unsigned n, enum rte_ring_queue_behavior behavior)
498 uint32_t cons_head, prod_tail;
499 uint32_t cons_next, entries;
500 const unsigned max = n;
503 uint32_t mask = r->mask;
505 /* Avoid the unnecessary cmpset operation below, which is also
506 * potentially harmful when n equals 0. */
510 /* move cons.head atomically */
512 /* Restore n as it may change every loop */
515 cons_head = r->cons.head;
516 prod_tail = r->prod.tail;
517 /* The subtraction is done between two unsigned 32bits value
518 * (the result is always modulo 32 bits even if we have
519 * cons_head > prod_tail). So 'entries' is always between 0
520 * and size(ring)-1. */
521 entries = (prod_tail - cons_head);
523 /* Set the actual entries for dequeue */
525 if (behavior == RTE_RING_QUEUE_FIXED)
528 if (unlikely(entries == 0))
534 cons_next = cons_head + n;
535 success = rte_atomic32_cmpset(&r->cons.head, cons_head,
537 } while (unlikely(success == 0));
544 * If there are other dequeues in progress that preceded us,
545 * we need to wait for them to complete
547 while (unlikely(r->cons.tail != cons_head))
550 r->cons.tail = cons_next;
556 * @internal Dequeue several objects from a ring (NOT multi-consumers safe).
557 * When the request objects are more than the available objects, only dequeue
558 * the actual number of objects
561 * A pointer to the ring structure.
563 * A pointer to a table of void * pointers (objects) that will be filled.
565 * The number of objects to dequeue from the ring to the obj_table.
567 * RTE_RING_QUEUE_FIXED: Dequeue a fixed number of items from a ring
568 * RTE_RING_QUEUE_VARIABLE: Dequeue as many items a possible from ring
570 * - Actual number of objects dequeued.
571 * If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
573 static inline unsigned int __attribute__((always_inline))
574 __rte_ring_sc_do_dequeue(struct rte_ring *r, void **obj_table,
575 unsigned n, enum rte_ring_queue_behavior behavior)
577 uint32_t cons_head, prod_tail;
578 uint32_t cons_next, entries;
580 uint32_t mask = r->mask;
582 cons_head = r->cons.head;
583 prod_tail = r->prod.tail;
584 /* The subtraction is done between two unsigned 32bits value
585 * (the result is always modulo 32 bits even if we have
586 * cons_head > prod_tail). So 'entries' is always between 0
587 * and size(ring)-1. */
588 entries = prod_tail - cons_head;
591 if (behavior == RTE_RING_QUEUE_FIXED)
594 if (unlikely(entries == 0))
600 cons_next = cons_head + n;
601 r->cons.head = cons_next;
607 r->cons.tail = cons_next;
612 * Enqueue several objects on the ring (multi-producers safe).
614 * This function uses a "compare and set" instruction to move the
615 * producer index atomically.
618 * A pointer to the ring structure.
620 * A pointer to a table of void * pointers (objects).
622 * The number of objects to add in the ring from the obj_table.
624 * The number of objects enqueued, either 0 or n
626 static inline unsigned int __attribute__((always_inline))
627 rte_ring_mp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
630 return __rte_ring_mp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
634 * Enqueue several objects on a ring (NOT multi-producers safe).
637 * A pointer to the ring structure.
639 * A pointer to a table of void * pointers (objects).
641 * The number of objects to add in the ring from the obj_table.
643 * The number of objects enqueued, either 0 or n
645 static inline unsigned int __attribute__((always_inline))
646 rte_ring_sp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
649 return __rte_ring_sp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
653 * Enqueue several objects on a ring.
655 * This function calls the multi-producer or the single-producer
656 * version depending on the default behavior that was specified at
657 * ring creation time (see flags).
660 * A pointer to the ring structure.
662 * A pointer to a table of void * pointers (objects).
664 * The number of objects to add in the ring from the obj_table.
666 * The number of objects enqueued, either 0 or n
668 static inline unsigned int __attribute__((always_inline))
669 rte_ring_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
673 return rte_ring_sp_enqueue_bulk(r, obj_table, n);
675 return rte_ring_mp_enqueue_bulk(r, obj_table, n);
679 * Enqueue one object on a ring (multi-producers safe).
681 * This function uses a "compare and set" instruction to move the
682 * producer index atomically.
685 * A pointer to the ring structure.
687 * A pointer to the object to be added.
689 * - 0: Success; objects enqueued.
690 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
692 static inline int __attribute__((always_inline))
693 rte_ring_mp_enqueue(struct rte_ring *r, void *obj)
695 return rte_ring_mp_enqueue_bulk(r, &obj, 1) ? 0 : -ENOBUFS;
699 * Enqueue one object on a ring (NOT multi-producers safe).
702 * A pointer to the ring structure.
704 * A pointer to the object to be added.
706 * - 0: Success; objects enqueued.
707 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
709 static inline int __attribute__((always_inline))
710 rte_ring_sp_enqueue(struct rte_ring *r, void *obj)
712 return rte_ring_sp_enqueue_bulk(r, &obj, 1) ? 0 : -ENOBUFS;
716 * Enqueue one object on a ring.
718 * This function calls the multi-producer or the single-producer
719 * version, depending on the default behaviour that was specified at
720 * ring creation time (see flags).
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_enqueue(struct rte_ring *r, void *obj)
733 return rte_ring_enqueue_bulk(r, &obj, 1) ? 0 : -ENOBUFS;
737 * Dequeue several objects from a ring (multi-consumers safe).
739 * This function uses a "compare and set" instruction to move the
740 * consumer index atomically.
743 * A pointer to the ring structure.
745 * A pointer to a table of void * pointers (objects) that will be filled.
747 * The number of objects to dequeue from the ring to the obj_table.
749 * The number of objects dequeued, either 0 or n
751 static inline unsigned int __attribute__((always_inline))
752 rte_ring_mc_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
754 return __rte_ring_mc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
758 * Dequeue several objects from a ring (NOT multi-consumers safe).
761 * A pointer to the ring structure.
763 * A pointer to a table of void * pointers (objects) that will be filled.
765 * The number of objects to dequeue from the ring to the obj_table,
766 * must be strictly positive.
768 * The number of objects dequeued, either 0 or n
770 static inline unsigned int __attribute__((always_inline))
771 rte_ring_sc_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
773 return __rte_ring_sc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
777 * Dequeue several objects from a ring.
779 * This function calls the multi-consumers or the single-consumer
780 * version, depending on the default behaviour that was specified at
781 * ring creation time (see flags).
784 * A pointer to the ring structure.
786 * A pointer to a table of void * pointers (objects) that will be filled.
788 * The number of objects to dequeue from the ring to the obj_table.
790 * The number of objects dequeued, either 0 or n
792 static inline unsigned int __attribute__((always_inline))
793 rte_ring_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
796 return rte_ring_sc_dequeue_bulk(r, obj_table, n);
798 return rte_ring_mc_dequeue_bulk(r, obj_table, n);
802 * Dequeue one object from a ring (multi-consumers safe).
804 * This function uses a "compare and set" instruction to move the
805 * consumer index atomically.
808 * A pointer to the ring structure.
810 * A pointer to a void * pointer (object) that will be filled.
812 * - 0: Success; objects dequeued.
813 * - -ENOENT: Not enough entries in the ring to dequeue; no object is
816 static inline int __attribute__((always_inline))
817 rte_ring_mc_dequeue(struct rte_ring *r, void **obj_p)
819 return rte_ring_mc_dequeue_bulk(r, obj_p, 1) ? 0 : -ENOBUFS;
823 * Dequeue one object from a ring (NOT multi-consumers safe).
826 * A pointer to the ring structure.
828 * A pointer to a void * pointer (object) that will be filled.
830 * - 0: Success; objects dequeued.
831 * - -ENOENT: Not enough entries in the ring to dequeue, no object is
834 static inline int __attribute__((always_inline))
835 rte_ring_sc_dequeue(struct rte_ring *r, void **obj_p)
837 return rte_ring_sc_dequeue_bulk(r, obj_p, 1) ? 0 : -ENOBUFS;
841 * Dequeue one object from a ring.
843 * This function calls the multi-consumers or the single-consumer
844 * version depending on the default behaviour that was specified at
845 * ring creation time (see flags).
848 * A pointer to the ring structure.
850 * A pointer to a void * pointer (object) that will be filled.
852 * - 0: Success, objects dequeued.
853 * - -ENOENT: Not enough entries in the ring to dequeue, no object is
856 static inline int __attribute__((always_inline))
857 rte_ring_dequeue(struct rte_ring *r, void **obj_p)
859 return rte_ring_dequeue_bulk(r, obj_p, 1) ? 0 : -ENOBUFS;
863 * Test if a ring is full.
866 * A pointer to the ring structure.
868 * - 1: The ring is full.
869 * - 0: The ring is not full.
872 rte_ring_full(const struct rte_ring *r)
874 uint32_t prod_tail = r->prod.tail;
875 uint32_t cons_tail = r->cons.tail;
876 return ((cons_tail - prod_tail - 1) & r->mask) == 0;
880 * Test if a ring is empty.
883 * A pointer to the ring structure.
885 * - 1: The ring is empty.
886 * - 0: The ring is not empty.
889 rte_ring_empty(const struct rte_ring *r)
891 uint32_t prod_tail = r->prod.tail;
892 uint32_t cons_tail = r->cons.tail;
893 return !!(cons_tail == prod_tail);
897 * Return the number of entries in a ring.
900 * A pointer to the ring structure.
902 * The number of entries in the ring.
904 static inline unsigned
905 rte_ring_count(const struct rte_ring *r)
907 uint32_t prod_tail = r->prod.tail;
908 uint32_t cons_tail = r->cons.tail;
909 return (prod_tail - cons_tail) & r->mask;
913 * Return the number of free entries in a ring.
916 * A pointer to the ring structure.
918 * The number of free entries in the ring.
920 static inline unsigned
921 rte_ring_free_count(const struct rte_ring *r)
923 uint32_t prod_tail = r->prod.tail;
924 uint32_t cons_tail = r->cons.tail;
925 return (cons_tail - prod_tail - 1) & r->mask;
929 * Return the size of the ring.
932 * A pointer to the ring structure.
934 * The number of elements which can be stored in the ring.
936 static inline unsigned int
937 rte_ring_get_size(const struct rte_ring *r)
943 * Dump the status of all rings on the console
946 * A pointer to a file for output
948 void rte_ring_list_dump(FILE *f);
951 * Search a ring from its name
954 * The name of the ring.
956 * The pointer to the ring matching the name, or NULL if not found,
957 * with rte_errno set appropriately. Possible rte_errno values include:
958 * - ENOENT - required entry not available to return.
960 struct rte_ring *rte_ring_lookup(const char *name);
963 * Enqueue several objects on the ring (multi-producers safe).
965 * This function uses a "compare and set" instruction to move the
966 * producer index atomically.
969 * A pointer to the ring structure.
971 * A pointer to a table of void * pointers (objects).
973 * The number of objects to add in the ring from the obj_table.
975 * - n: Actual number of objects enqueued.
977 static inline unsigned __attribute__((always_inline))
978 rte_ring_mp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
981 return __rte_ring_mp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
985 * Enqueue several objects on a ring (NOT multi-producers safe).
988 * A pointer to the ring structure.
990 * A pointer to a table of void * pointers (objects).
992 * The number of objects to add in the ring from the obj_table.
994 * - n: Actual number of objects enqueued.
996 static inline unsigned __attribute__((always_inline))
997 rte_ring_sp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
1000 return __rte_ring_sp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
1004 * Enqueue several objects on a ring.
1006 * This function calls the multi-producer or the single-producer
1007 * version depending on the default behavior that was specified at
1008 * ring creation time (see flags).
1011 * A pointer to the ring structure.
1013 * A pointer to a table of void * pointers (objects).
1015 * The number of objects to add in the ring from the obj_table.
1017 * - n: Actual number of objects enqueued.
1019 static inline unsigned __attribute__((always_inline))
1020 rte_ring_enqueue_burst(struct rte_ring *r, void * const *obj_table,
1024 return rte_ring_sp_enqueue_burst(r, obj_table, n);
1026 return rte_ring_mp_enqueue_burst(r, obj_table, n);
1030 * Dequeue several objects from a ring (multi-consumers safe). When the request
1031 * objects are more than the available objects, only dequeue the actual number
1034 * This function uses a "compare and set" instruction to move the
1035 * consumer index atomically.
1038 * A pointer to the ring structure.
1040 * A pointer to a table of void * pointers (objects) that will be filled.
1042 * The number of objects to dequeue from the ring to the obj_table.
1044 * - n: Actual number of objects dequeued, 0 if ring is empty
1046 static inline unsigned __attribute__((always_inline))
1047 rte_ring_mc_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
1049 return __rte_ring_mc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
1053 * Dequeue several objects from a ring (NOT multi-consumers safe).When the
1054 * request objects are more than the available objects, only dequeue the
1055 * actual number of objects
1058 * A pointer to the ring structure.
1060 * A pointer to a table of void * pointers (objects) that will be filled.
1062 * The number of objects to dequeue from the ring to the obj_table.
1064 * - n: Actual number of objects dequeued, 0 if ring is empty
1066 static inline unsigned __attribute__((always_inline))
1067 rte_ring_sc_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
1069 return __rte_ring_sc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
1073 * Dequeue multiple objects from a ring up to a maximum number.
1075 * This function calls the multi-consumers or the single-consumer
1076 * version, depending on the default behaviour that was specified at
1077 * ring creation time (see flags).
1080 * A pointer to the ring structure.
1082 * A pointer to a table of void * pointers (objects) that will be filled.
1084 * The number of objects to dequeue from the ring to the obj_table.
1086 * - Number of objects dequeued
1088 static inline unsigned __attribute__((always_inline))
1089 rte_ring_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
1092 return rte_ring_sc_dequeue_burst(r, obj_table, n);
1094 return rte_ring_mc_dequeue_burst(r, obj_table, n);
1101 #endif /* _RTE_RING_H_ */