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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_config.h>
100 #include <rte_memory.h>
101 #include <rte_lcore.h>
102 #include <rte_atomic.h>
103 #include <rte_branch_prediction.h>
104 #include <rte_memzone.h>
105 #include <rte_pause.h>
107 #define RTE_TAILQ_RING_NAME "RTE_RING"
109 enum rte_ring_queue_behavior {
110 RTE_RING_QUEUE_FIXED = 0, /* Enq/Deq a fixed number of items from a ring */
111 RTE_RING_QUEUE_VARIABLE /* Enq/Deq as many items as possible from ring */
114 #define RTE_RING_MZ_PREFIX "RG_"
115 /**< The maximum length of a ring name. */
116 #define RTE_RING_NAMESIZE (RTE_MEMZONE_NAMESIZE - \
117 sizeof(RTE_RING_MZ_PREFIX) + 1)
119 struct rte_memzone; /* forward declaration, so as not to require memzone.h */
121 #if RTE_CACHE_LINE_SIZE < 128
122 #define PROD_ALIGN (RTE_CACHE_LINE_SIZE * 2)
123 #define CONS_ALIGN (RTE_CACHE_LINE_SIZE * 2)
125 #define PROD_ALIGN RTE_CACHE_LINE_SIZE
126 #define CONS_ALIGN RTE_CACHE_LINE_SIZE
129 /* structure to hold a pair of head/tail values and other metadata */
130 struct rte_ring_headtail {
131 volatile uint32_t head; /**< Prod/consumer head. */
132 volatile uint32_t tail; /**< Prod/consumer tail. */
133 uint32_t single; /**< True if single prod/cons */
137 * An RTE ring structure.
139 * The producer and the consumer have a head and a tail index. The particularity
140 * of these index is that they are not between 0 and size(ring). These indexes
141 * are between 0 and 2^32, and we mask their value when we access the ring[]
142 * field. Thanks to this assumption, we can do subtractions between 2 index
143 * values in a modulo-32bit base: that's why the overflow of the indexes is not
148 * Note: this field kept the RTE_MEMZONE_NAMESIZE size due to ABI
149 * compatibility requirements, it could be changed to RTE_RING_NAMESIZE
150 * next time the ABI changes
152 char name[RTE_MEMZONE_NAMESIZE] __rte_cache_aligned; /**< Name of the ring. */
153 int flags; /**< Flags supplied at creation. */
154 const struct rte_memzone *memzone;
155 /**< Memzone, if any, containing the rte_ring */
156 uint32_t size; /**< Size of ring. */
157 uint32_t mask; /**< Mask (size-1) of ring. */
158 uint32_t capacity; /**< Usable size of ring */
160 /** Ring producer status. */
161 struct rte_ring_headtail prod __rte_aligned(PROD_ALIGN);
163 /** Ring consumer status. */
164 struct rte_ring_headtail cons __rte_aligned(CONS_ALIGN);
167 #define RING_F_SP_ENQ 0x0001 /**< The default enqueue is "single-producer". */
168 #define RING_F_SC_DEQ 0x0002 /**< The default dequeue is "single-consumer". */
170 * Ring is to hold exactly requested number of entries.
171 * Without this flag set, the ring size requested must be a power of 2, and the
172 * usable space will be that size - 1. With the flag, the requested size will
173 * be rounded up to the next power of two, but the usable space will be exactly
174 * that requested. Worst case, if a power-of-2 size is requested, half the
175 * ring space will be wasted.
177 #define RING_F_EXACT_SZ 0x0004
178 #define RTE_RING_SZ_MASK (0x7fffffffU) /**< Ring size mask */
180 /* @internal defines for passing to the enqueue dequeue worker functions */
187 * Calculate the memory size needed for a ring
189 * This function returns the number of bytes needed for a ring, given
190 * the number of elements in it. This value is the sum of the size of
191 * the structure rte_ring and the size of the memory needed by the
192 * objects pointers. The value is aligned to a cache line size.
195 * The number of elements in the ring (must be a power of 2).
197 * - The memory size needed for the ring on success.
198 * - -EINVAL if count is not a power of 2.
200 ssize_t rte_ring_get_memsize(unsigned count);
203 * Initialize a ring structure.
205 * Initialize a ring structure in memory pointed by "r". The size of the
206 * memory area must be large enough to store the ring structure and the
207 * object table. It is advised to use rte_ring_get_memsize() to get the
210 * The ring size is set to *count*, which must be a power of two. Water
211 * marking is disabled by default. The real usable ring size is
212 * *count-1* instead of *count* to differentiate a free ring from an
215 * The ring is not added in RTE_TAILQ_RING global list. Indeed, the
216 * memory given by the caller may not be shareable among dpdk
220 * The pointer to the ring structure followed by the objects table.
222 * The name of the ring.
224 * The number of elements in the ring (must be a power of 2).
226 * An OR of the following:
227 * - RING_F_SP_ENQ: If this flag is set, the default behavior when
228 * using ``rte_ring_enqueue()`` or ``rte_ring_enqueue_bulk()``
229 * is "single-producer". Otherwise, it is "multi-producers".
230 * - RING_F_SC_DEQ: If this flag is set, the default behavior when
231 * using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``
232 * is "single-consumer". Otherwise, it is "multi-consumers".
234 * 0 on success, or a negative value on error.
236 int rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
240 * Create a new ring named *name* in memory.
242 * This function uses ``memzone_reserve()`` to allocate memory. Then it
243 * calls rte_ring_init() to initialize an empty ring.
245 * The new ring size is set to *count*, which must be a power of
246 * two. Water marking is disabled by default. The real usable ring size
247 * is *count-1* instead of *count* to differentiate a free ring from an
250 * The ring is added in RTE_TAILQ_RING list.
253 * The name of the ring.
255 * The size of the ring (must be a power of 2).
257 * The *socket_id* argument is the socket identifier in case of
258 * NUMA. The value can be *SOCKET_ID_ANY* if there is no NUMA
259 * constraint for the reserved zone.
261 * An OR of the following:
262 * - RING_F_SP_ENQ: If this flag is set, the default behavior when
263 * using ``rte_ring_enqueue()`` or ``rte_ring_enqueue_bulk()``
264 * is "single-producer". Otherwise, it is "multi-producers".
265 * - RING_F_SC_DEQ: If this flag is set, the default behavior when
266 * using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``
267 * is "single-consumer". Otherwise, it is "multi-consumers".
269 * On success, the pointer to the new allocated ring. NULL on error with
270 * rte_errno set appropriately. Possible errno values include:
271 * - E_RTE_NO_CONFIG - function could not get pointer to rte_config structure
272 * - E_RTE_SECONDARY - function was called from a secondary process instance
273 * - EINVAL - count provided is not a power of 2
274 * - ENOSPC - the maximum number of memzones has already been allocated
275 * - EEXIST - a memzone with the same name already exists
276 * - ENOMEM - no appropriate memory area found in which to create memzone
278 struct rte_ring *rte_ring_create(const char *name, unsigned count,
279 int socket_id, unsigned flags);
281 * De-allocate all memory used by the ring.
286 void rte_ring_free(struct rte_ring *r);
289 * Dump the status of the ring to a file.
292 * A pointer to a file for output
294 * A pointer to the ring structure.
296 void rte_ring_dump(FILE *f, const struct rte_ring *r);
298 /* the actual enqueue of pointers on the ring.
299 * Placed here since identical code needed in both
300 * single and multi producer enqueue functions */
301 #define ENQUEUE_PTRS(r, ring_start, prod_head, obj_table, n, obj_type) do { \
303 const uint32_t size = (r)->size; \
304 uint32_t idx = prod_head & (r)->mask; \
305 obj_type *ring = (obj_type *)ring_start; \
306 if (likely(idx + n < size)) { \
307 for (i = 0; i < (n & ((~(unsigned)0x3))); i+=4, idx+=4) { \
308 ring[idx] = obj_table[i]; \
309 ring[idx+1] = obj_table[i+1]; \
310 ring[idx+2] = obj_table[i+2]; \
311 ring[idx+3] = obj_table[i+3]; \
315 ring[idx++] = obj_table[i++]; /* fallthrough */ \
317 ring[idx++] = obj_table[i++]; /* fallthrough */ \
319 ring[idx++] = obj_table[i++]; \
322 for (i = 0; idx < size; i++, idx++)\
323 ring[idx] = obj_table[i]; \
324 for (idx = 0; i < n; i++, idx++) \
325 ring[idx] = obj_table[i]; \
329 /* the actual copy of pointers on the ring to obj_table.
330 * Placed here since identical code needed in both
331 * single and multi consumer dequeue functions */
332 #define DEQUEUE_PTRS(r, ring_start, cons_head, obj_table, n, obj_type) do { \
334 uint32_t idx = cons_head & (r)->mask; \
335 const uint32_t size = (r)->size; \
336 obj_type *ring = (obj_type *)ring_start; \
337 if (likely(idx + n < size)) { \
338 for (i = 0; i < (n & (~(unsigned)0x3)); i+=4, idx+=4) {\
339 obj_table[i] = ring[idx]; \
340 obj_table[i+1] = ring[idx+1]; \
341 obj_table[i+2] = ring[idx+2]; \
342 obj_table[i+3] = ring[idx+3]; \
346 obj_table[i++] = ring[idx++]; /* fallthrough */ \
348 obj_table[i++] = ring[idx++]; /* fallthrough */ \
350 obj_table[i++] = ring[idx++]; \
353 for (i = 0; idx < size; i++, idx++) \
354 obj_table[i] = ring[idx]; \
355 for (idx = 0; i < n; i++, idx++) \
356 obj_table[i] = ring[idx]; \
360 /* Between load and load. there might be cpu reorder in weak model
362 * There are 2 choices for the users
363 * 1.use rmb() memory barrier
364 * 2.use one-direcion load_acquire/store_release barrier,defined by
365 * CONFIG_RTE_RING_USE_C11_MEM_MODEL=y
366 * It depends on performance test results.
367 * By default, move common functions to rte_ring_generic.h
369 #ifdef RTE_RING_USE_C11_MEM_MODEL
370 #include "rte_ring_c11_mem.h"
372 #include "rte_ring_generic.h"
376 * @internal Enqueue several objects on the ring
379 * A pointer to the ring structure.
381 * A pointer to a table of void * pointers (objects).
383 * The number of objects to add in the ring from the obj_table.
385 * RTE_RING_QUEUE_FIXED: Enqueue a fixed number of items from a ring
386 * RTE_RING_QUEUE_VARIABLE: Enqueue as many items as possible from ring
388 * Indicates whether to use single producer or multi-producer head update
390 * returns the amount of space after the enqueue operation has finished
392 * Actual number of objects enqueued.
393 * If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
395 static __rte_always_inline unsigned int
396 __rte_ring_do_enqueue(struct rte_ring *r, void * const *obj_table,
397 unsigned int n, enum rte_ring_queue_behavior behavior,
398 int is_sp, unsigned int *free_space)
400 uint32_t prod_head, prod_next;
401 uint32_t free_entries;
403 n = __rte_ring_move_prod_head(r, is_sp, n, behavior,
404 &prod_head, &prod_next, &free_entries);
408 ENQUEUE_PTRS(r, &r[1], prod_head, obj_table, n, void *);
410 update_tail(&r->prod, prod_head, prod_next, is_sp, 1);
412 if (free_space != NULL)
413 *free_space = free_entries - n;
418 * @internal Dequeue several objects from the ring
421 * A pointer to the ring structure.
423 * A pointer to a table of void * pointers (objects).
425 * The number of objects to pull from the ring.
427 * RTE_RING_QUEUE_FIXED: Dequeue a fixed number of items from a ring
428 * RTE_RING_QUEUE_VARIABLE: Dequeue as many items as possible from ring
430 * Indicates whether to use single consumer or multi-consumer head update
432 * returns the number of remaining ring entries after the dequeue has finished
434 * - Actual number of objects dequeued.
435 * If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.
437 static __rte_always_inline unsigned int
438 __rte_ring_do_dequeue(struct rte_ring *r, void **obj_table,
439 unsigned int n, enum rte_ring_queue_behavior behavior,
440 int is_sc, unsigned int *available)
442 uint32_t cons_head, cons_next;
445 n = __rte_ring_move_cons_head(r, is_sc, n, behavior,
446 &cons_head, &cons_next, &entries);
450 DEQUEUE_PTRS(r, &r[1], cons_head, obj_table, n, void *);
452 update_tail(&r->cons, cons_head, cons_next, is_sc, 0);
455 if (available != NULL)
456 *available = entries - n;
461 * Enqueue several objects on the ring (multi-producers safe).
463 * This function uses a "compare and set" instruction to move the
464 * producer index atomically.
467 * A pointer to the ring structure.
469 * A pointer to a table of void * pointers (objects).
471 * The number of objects to add in the ring from the obj_table.
473 * if non-NULL, returns the amount of space in the ring after the
474 * enqueue operation has finished.
476 * The number of objects enqueued, either 0 or n
478 static __rte_always_inline unsigned int
479 rte_ring_mp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
480 unsigned int n, unsigned int *free_space)
482 return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
483 __IS_MP, free_space);
487 * Enqueue several objects on a ring (NOT multi-producers safe).
490 * A pointer to the ring structure.
492 * A pointer to a table of void * pointers (objects).
494 * The number of objects to add in the ring from the obj_table.
496 * if non-NULL, returns the amount of space in the ring after the
497 * enqueue operation has finished.
499 * The number of objects enqueued, either 0 or n
501 static __rte_always_inline unsigned int
502 rte_ring_sp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
503 unsigned int n, unsigned int *free_space)
505 return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
506 __IS_SP, free_space);
510 * Enqueue several objects on a ring.
512 * This function calls the multi-producer or the single-producer
513 * version depending on the default behavior that was specified at
514 * ring creation time (see flags).
517 * A pointer to the ring structure.
519 * A pointer to a table of void * pointers (objects).
521 * The number of objects to add in the ring from the obj_table.
523 * if non-NULL, returns the amount of space in the ring after the
524 * enqueue operation has finished.
526 * The number of objects enqueued, either 0 or n
528 static __rte_always_inline unsigned int
529 rte_ring_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
530 unsigned int n, unsigned int *free_space)
532 return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
533 r->prod.single, free_space);
537 * Enqueue one object on a ring (multi-producers safe).
539 * This function uses a "compare and set" instruction to move the
540 * producer index atomically.
543 * A pointer to the ring structure.
545 * A pointer to the object to be added.
547 * - 0: Success; objects enqueued.
548 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
550 static __rte_always_inline int
551 rte_ring_mp_enqueue(struct rte_ring *r, void *obj)
553 return rte_ring_mp_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
557 * Enqueue one object on a ring (NOT multi-producers safe).
560 * A pointer to the ring structure.
562 * A pointer to the object to be added.
564 * - 0: Success; objects enqueued.
565 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
567 static __rte_always_inline int
568 rte_ring_sp_enqueue(struct rte_ring *r, void *obj)
570 return rte_ring_sp_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
574 * Enqueue one object on a ring.
576 * This function calls the multi-producer or the single-producer
577 * version, depending on the default behaviour that was specified at
578 * ring creation time (see flags).
581 * A pointer to the ring structure.
583 * A pointer to the object to be added.
585 * - 0: Success; objects enqueued.
586 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
588 static __rte_always_inline int
589 rte_ring_enqueue(struct rte_ring *r, void *obj)
591 return rte_ring_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
595 * Dequeue several objects from a ring (multi-consumers safe).
597 * This function uses a "compare and set" instruction to move the
598 * consumer index atomically.
601 * A pointer to the ring structure.
603 * A pointer to a table of void * pointers (objects) that will be filled.
605 * The number of objects to dequeue from the ring to the obj_table.
607 * If non-NULL, returns the number of remaining ring entries after the
608 * dequeue has finished.
610 * The number of objects dequeued, either 0 or n
612 static __rte_always_inline unsigned int
613 rte_ring_mc_dequeue_bulk(struct rte_ring *r, void **obj_table,
614 unsigned int n, unsigned int *available)
616 return __rte_ring_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
621 * Dequeue several objects from a ring (NOT multi-consumers safe).
624 * A pointer to the ring structure.
626 * A pointer to a table of void * pointers (objects) that will be filled.
628 * The number of objects to dequeue from the ring to the obj_table,
629 * must be strictly positive.
631 * If non-NULL, returns the number of remaining ring entries after the
632 * dequeue has finished.
634 * The number of objects dequeued, either 0 or n
636 static __rte_always_inline unsigned int
637 rte_ring_sc_dequeue_bulk(struct rte_ring *r, void **obj_table,
638 unsigned int n, unsigned int *available)
640 return __rte_ring_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
645 * Dequeue several objects from a ring.
647 * This function calls the multi-consumers or the single-consumer
648 * version, depending on the default behaviour that was specified at
649 * ring creation time (see flags).
652 * A pointer to the ring structure.
654 * A pointer to a table of void * pointers (objects) that will be filled.
656 * The number of objects to dequeue from the ring to the obj_table.
658 * If non-NULL, returns the number of remaining ring entries after the
659 * dequeue has finished.
661 * The number of objects dequeued, either 0 or n
663 static __rte_always_inline unsigned int
664 rte_ring_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned int n,
665 unsigned int *available)
667 return __rte_ring_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED,
668 r->cons.single, available);
672 * Dequeue one object from a ring (multi-consumers safe).
674 * This function uses a "compare and set" instruction to move the
675 * consumer index atomically.
678 * A pointer to the ring structure.
680 * A pointer to a void * pointer (object) that will be filled.
682 * - 0: Success; objects dequeued.
683 * - -ENOENT: Not enough entries in the ring to dequeue; no object is
686 static __rte_always_inline int
687 rte_ring_mc_dequeue(struct rte_ring *r, void **obj_p)
689 return rte_ring_mc_dequeue_bulk(r, obj_p, 1, NULL) ? 0 : -ENOENT;
693 * Dequeue one object from a ring (NOT multi-consumers safe).
696 * A pointer to the ring structure.
698 * A pointer to a void * pointer (object) that will be filled.
700 * - 0: Success; objects dequeued.
701 * - -ENOENT: Not enough entries in the ring to dequeue, no object is
704 static __rte_always_inline int
705 rte_ring_sc_dequeue(struct rte_ring *r, void **obj_p)
707 return rte_ring_sc_dequeue_bulk(r, obj_p, 1, NULL) ? 0 : -ENOENT;
711 * Dequeue one object from a ring.
713 * This function calls the multi-consumers or the single-consumer
714 * version depending on the default behaviour that was specified at
715 * ring creation time (see flags).
718 * A pointer to the ring structure.
720 * A pointer to a void * pointer (object) that will be filled.
722 * - 0: Success, objects dequeued.
723 * - -ENOENT: Not enough entries in the ring to dequeue, no object is
726 static __rte_always_inline int
727 rte_ring_dequeue(struct rte_ring *r, void **obj_p)
729 return rte_ring_dequeue_bulk(r, obj_p, 1, NULL) ? 0 : -ENOENT;
733 * Return the number of entries in a ring.
736 * A pointer to the ring structure.
738 * The number of entries in the ring.
740 static inline unsigned
741 rte_ring_count(const struct rte_ring *r)
743 uint32_t prod_tail = r->prod.tail;
744 uint32_t cons_tail = r->cons.tail;
745 uint32_t count = (prod_tail - cons_tail) & r->mask;
746 return (count > r->capacity) ? r->capacity : count;
750 * Return the number of free entries in a ring.
753 * A pointer to the ring structure.
755 * The number of free entries in the ring.
757 static inline unsigned
758 rte_ring_free_count(const struct rte_ring *r)
760 return r->capacity - rte_ring_count(r);
764 * Test if a ring is full.
767 * A pointer to the ring structure.
769 * - 1: The ring is full.
770 * - 0: The ring is not full.
773 rte_ring_full(const struct rte_ring *r)
775 return rte_ring_free_count(r) == 0;
779 * Test if a ring is empty.
782 * A pointer to the ring structure.
784 * - 1: The ring is empty.
785 * - 0: The ring is not empty.
788 rte_ring_empty(const struct rte_ring *r)
790 return rte_ring_count(r) == 0;
794 * Return the size of the ring.
797 * A pointer to the ring structure.
799 * The size of the data store used by the ring.
800 * NOTE: this is not the same as the usable space in the ring. To query that
801 * use ``rte_ring_get_capacity()``.
803 static inline unsigned int
804 rte_ring_get_size(const struct rte_ring *r)
810 * Return the number of elements which can be stored in the ring.
813 * A pointer to the ring structure.
815 * The usable size of the ring.
817 static inline unsigned int
818 rte_ring_get_capacity(const struct rte_ring *r)
824 * Dump the status of all rings on the console
827 * A pointer to a file for output
829 void rte_ring_list_dump(FILE *f);
832 * Search a ring from its name
835 * The name of the ring.
837 * The pointer to the ring matching the name, or NULL if not found,
838 * with rte_errno set appropriately. Possible rte_errno values include:
839 * - ENOENT - required entry not available to return.
841 struct rte_ring *rte_ring_lookup(const char *name);
844 * Enqueue several objects on the ring (multi-producers safe).
846 * This function uses a "compare and set" instruction to move the
847 * producer index atomically.
850 * A pointer to the ring structure.
852 * A pointer to a table of void * pointers (objects).
854 * The number of objects to add in the ring from the obj_table.
856 * if non-NULL, returns the amount of space in the ring after the
857 * enqueue operation has finished.
859 * - n: Actual number of objects enqueued.
861 static __rte_always_inline unsigned
862 rte_ring_mp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
863 unsigned int n, unsigned int *free_space)
865 return __rte_ring_do_enqueue(r, obj_table, n,
866 RTE_RING_QUEUE_VARIABLE, __IS_MP, free_space);
870 * Enqueue several objects on a ring (NOT multi-producers safe).
873 * A pointer to the ring structure.
875 * A pointer to a table of void * pointers (objects).
877 * The number of objects to add in the ring from the obj_table.
879 * if non-NULL, returns the amount of space in the ring after the
880 * enqueue operation has finished.
882 * - n: Actual number of objects enqueued.
884 static __rte_always_inline unsigned
885 rte_ring_sp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
886 unsigned int n, unsigned int *free_space)
888 return __rte_ring_do_enqueue(r, obj_table, n,
889 RTE_RING_QUEUE_VARIABLE, __IS_SP, free_space);
893 * Enqueue several objects on a ring.
895 * This function calls the multi-producer or the single-producer
896 * version depending on the default behavior that was specified at
897 * ring creation time (see flags).
900 * A pointer to the ring structure.
902 * A pointer to a table of void * pointers (objects).
904 * The number of objects to add in the ring from the obj_table.
906 * if non-NULL, returns the amount of space in the ring after the
907 * enqueue operation has finished.
909 * - n: Actual number of objects enqueued.
911 static __rte_always_inline unsigned
912 rte_ring_enqueue_burst(struct rte_ring *r, void * const *obj_table,
913 unsigned int n, unsigned int *free_space)
915 return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE,
916 r->prod.single, free_space);
920 * Dequeue several objects from a ring (multi-consumers safe). When the request
921 * objects are more than the available objects, only dequeue the actual number
924 * This function uses a "compare and set" instruction to move the
925 * consumer index atomically.
928 * A pointer to the ring structure.
930 * A pointer to a table of void * pointers (objects) that will be filled.
932 * The number of objects to dequeue from the ring to the obj_table.
934 * If non-NULL, returns the number of remaining ring entries after the
935 * dequeue has finished.
937 * - n: Actual number of objects dequeued, 0 if ring is empty
939 static __rte_always_inline unsigned
940 rte_ring_mc_dequeue_burst(struct rte_ring *r, void **obj_table,
941 unsigned int n, unsigned int *available)
943 return __rte_ring_do_dequeue(r, obj_table, n,
944 RTE_RING_QUEUE_VARIABLE, __IS_MC, available);
948 * Dequeue several objects from a ring (NOT multi-consumers safe).When the
949 * request objects are more than the available objects, only dequeue the
950 * actual number of objects
953 * A pointer to the ring structure.
955 * A pointer to a table of void * pointers (objects) that will be filled.
957 * The number of objects to dequeue from the ring to the obj_table.
959 * If non-NULL, returns the number of remaining ring entries after the
960 * dequeue has finished.
962 * - n: Actual number of objects dequeued, 0 if ring is empty
964 static __rte_always_inline unsigned
965 rte_ring_sc_dequeue_burst(struct rte_ring *r, void **obj_table,
966 unsigned int n, unsigned int *available)
968 return __rte_ring_do_dequeue(r, obj_table, n,
969 RTE_RING_QUEUE_VARIABLE, __IS_SC, available);
973 * Dequeue multiple objects from a ring up to a maximum number.
975 * This function calls the multi-consumers or the single-consumer
976 * version, depending on the default behaviour that was specified at
977 * ring creation time (see flags).
980 * A pointer to the ring structure.
982 * A pointer to a table of void * pointers (objects) that will be filled.
984 * The number of objects to dequeue from the ring to the obj_table.
986 * If non-NULL, returns the number of remaining ring entries after the
987 * dequeue has finished.
989 * - Number of objects dequeued
991 static __rte_always_inline unsigned
992 rte_ring_dequeue_burst(struct rte_ring *r, void **obj_table,
993 unsigned int n, unsigned int *available)
995 return __rte_ring_do_dequeue(r, obj_table, n,
996 RTE_RING_QUEUE_VARIABLE,
997 r->cons.single, available);
1004 #endif /* _RTE_RING_H_ */