4 * Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
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8 * modification, are permitted provided that the following conditions
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14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
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18 * contributors may be used to endorse or promote products derived
19 * from this software without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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24 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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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 a possible from ring */
112 #ifdef RTE_LIBRTE_RING_DEBUG
114 * A structure that stores the ring statistics (per-lcore).
116 struct rte_ring_debug_stats {
117 uint64_t enq_success_bulk; /**< Successful enqueues number. */
118 uint64_t enq_success_objs; /**< Objects successfully enqueued. */
119 uint64_t enq_quota_bulk; /**< Successful enqueues above watermark. */
120 uint64_t enq_quota_objs; /**< Objects enqueued above watermark. */
121 uint64_t enq_fail_bulk; /**< Failed enqueues number. */
122 uint64_t enq_fail_objs; /**< Objects that failed to be enqueued. */
123 uint64_t deq_success_bulk; /**< Successful dequeues number. */
124 uint64_t deq_success_objs; /**< Objects successfully dequeued. */
125 uint64_t deq_fail_bulk; /**< Failed dequeues number. */
126 uint64_t deq_fail_objs; /**< Objects that failed to be dequeued. */
127 } __rte_cache_aligned;
130 #define RTE_RING_MZ_PREFIX "RG_"
131 /**< The maximum length of a ring name. */
132 #define RTE_RING_NAMESIZE (RTE_MEMZONE_NAMESIZE - \
133 sizeof(RTE_RING_MZ_PREFIX) + 1)
135 #ifndef RTE_RING_PAUSE_REP_COUNT
136 #define RTE_RING_PAUSE_REP_COUNT 0 /**< Yield after pause num of times, no yield
137 * if RTE_RING_PAUSE_REP not defined. */
140 struct rte_memzone; /* forward declaration, so as not to require memzone.h */
143 * An RTE ring structure.
145 * The producer and the consumer have a head and a tail index. The particularity
146 * of these index is that they are not between 0 and size(ring). These indexes
147 * are between 0 and 2^32, and we mask their value when we access the ring[]
148 * field. Thanks to this assumption, we can do subtractions between 2 index
149 * values in a modulo-32bit base: that's why the overflow of the indexes is not
154 * Note: this field kept the RTE_MEMZONE_NAMESIZE size due to ABI
155 * compatibility requirements, it could be changed to RTE_RING_NAMESIZE
156 * next time the ABI changes
158 char name[RTE_MEMZONE_NAMESIZE]; /**< Name of the ring. */
159 int flags; /**< Flags supplied at creation. */
160 const struct rte_memzone *memzone;
161 /**< Memzone, if any, containing the rte_ring */
163 /** Ring producer status. */
165 uint32_t watermark; /**< Maximum items before EDQUOT. */
166 uint32_t sp_enqueue; /**< True, if single producer. */
167 uint32_t size; /**< Size of ring. */
168 uint32_t mask; /**< Mask (size-1) of ring. */
169 volatile uint32_t head; /**< Producer head. */
170 volatile uint32_t tail; /**< Producer tail. */
171 } prod __rte_cache_aligned;
173 /** Ring consumer status. */
175 uint32_t sc_dequeue; /**< True, if single consumer. */
176 uint32_t size; /**< Size of the ring. */
177 uint32_t mask; /**< Mask (size-1) of ring. */
178 volatile uint32_t head; /**< Consumer head. */
179 volatile uint32_t tail; /**< Consumer tail. */
180 #ifdef RTE_RING_SPLIT_PROD_CONS
181 } cons __rte_cache_aligned;
186 #ifdef RTE_LIBRTE_RING_DEBUG
187 struct rte_ring_debug_stats stats[RTE_MAX_LCORE];
190 void *ring[] __rte_cache_aligned; /**< Memory space of ring starts here.
191 * not volatile so need to be careful
192 * about compiler re-ordering */
195 #define RING_F_SP_ENQ 0x0001 /**< The default enqueue is "single-producer". */
196 #define RING_F_SC_DEQ 0x0002 /**< The default dequeue is "single-consumer". */
197 #define RTE_RING_QUOT_EXCEED (1 << 31) /**< Quota exceed for burst ops */
198 #define RTE_RING_SZ_MASK (unsigned)(0x0fffffff) /**< Ring size mask */
201 * @internal When debug is enabled, store ring statistics.
203 * A pointer to the ring.
205 * The name of the statistics field to increment in the ring.
207 * The number to add to the object-oriented statistics.
209 #ifdef RTE_LIBRTE_RING_DEBUG
210 #define __RING_STAT_ADD(r, name, n) do { \
211 unsigned __lcore_id = rte_lcore_id(); \
212 if (__lcore_id < RTE_MAX_LCORE) { \
213 r->stats[__lcore_id].name##_objs += n; \
214 r->stats[__lcore_id].name##_bulk += 1; \
218 #define __RING_STAT_ADD(r, name, n) do {} while(0)
222 * Calculate the memory size needed for a ring
224 * This function returns the number of bytes needed for a ring, given
225 * the number of elements in it. This value is the sum of the size of
226 * the structure rte_ring and the size of the memory needed by the
227 * objects pointers. The value is aligned to a cache line size.
230 * The number of elements in the ring (must be a power of 2).
232 * - The memory size needed for the ring on success.
233 * - -EINVAL if count is not a power of 2.
235 ssize_t rte_ring_get_memsize(unsigned count);
238 * Initialize a ring structure.
240 * Initialize a ring structure in memory pointed by "r". The size of the
241 * memory area must be large enough to store the ring structure and the
242 * object table. It is advised to use rte_ring_get_memsize() to get the
245 * The ring size is set to *count*, which must be a power of two. Water
246 * marking is disabled by default. The real usable ring size is
247 * *count-1* instead of *count* to differentiate a free ring from an
250 * The ring is not added in RTE_TAILQ_RING global list. Indeed, the
251 * memory given by the caller may not be shareable among dpdk
255 * The pointer to the ring structure followed by the objects table.
257 * The name of the ring.
259 * The number of elements in the ring (must be a power of 2).
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 * 0 on success, or a negative value on error.
271 int rte_ring_init(struct rte_ring *r, const char *name, unsigned count,
275 * Create a new ring named *name* in memory.
277 * This function uses ``memzone_reserve()`` to allocate memory. Then it
278 * calls rte_ring_init() to initialize an empty ring.
280 * The new ring size is set to *count*, which must be a power of
281 * two. Water marking is disabled by default. The real usable ring size
282 * is *count-1* instead of *count* to differentiate a free ring from an
285 * The ring is added in RTE_TAILQ_RING list.
288 * The name of the ring.
290 * The size of the ring (must be a power of 2).
292 * The *socket_id* argument is the socket identifier in case of
293 * NUMA. The value can be *SOCKET_ID_ANY* if there is no NUMA
294 * constraint for the reserved zone.
296 * An OR of the following:
297 * - RING_F_SP_ENQ: If this flag is set, the default behavior when
298 * using ``rte_ring_enqueue()`` or ``rte_ring_enqueue_bulk()``
299 * is "single-producer". Otherwise, it is "multi-producers".
300 * - RING_F_SC_DEQ: If this flag is set, the default behavior when
301 * using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``
302 * is "single-consumer". Otherwise, it is "multi-consumers".
304 * On success, the pointer to the new allocated ring. NULL on error with
305 * rte_errno set appropriately. Possible errno values include:
306 * - E_RTE_NO_CONFIG - function could not get pointer to rte_config structure
307 * - E_RTE_SECONDARY - function was called from a secondary process instance
308 * - EINVAL - count provided is not a power of 2
309 * - ENOSPC - the maximum number of memzones has already been allocated
310 * - EEXIST - a memzone with the same name already exists
311 * - ENOMEM - no appropriate memory area found in which to create memzone
313 struct rte_ring *rte_ring_create(const char *name, unsigned count,
314 int socket_id, unsigned flags);
316 * De-allocate all memory used by the ring.
321 void rte_ring_free(struct rte_ring *r);
324 * Change the high water mark.
326 * If *count* is 0, water marking is disabled. Otherwise, it is set to the
327 * *count* value. The *count* value must be greater than 0 and less
328 * than the ring size.
330 * This function can be called at any time (not necessarily at
334 * A pointer to the ring structure.
336 * The new water mark value.
338 * - 0: Success; water mark changed.
339 * - -EINVAL: Invalid water mark value.
341 int rte_ring_set_water_mark(struct rte_ring *r, unsigned count);
344 * Dump the status of the ring to a file.
347 * A pointer to a file for output
349 * A pointer to the ring structure.
351 void rte_ring_dump(FILE *f, const struct rte_ring *r);
353 /* the actual enqueue of pointers on the ring.
354 * Placed here since identical code needed in both
355 * single and multi producer enqueue functions */
356 #define ENQUEUE_PTRS() do { \
357 const uint32_t size = r->prod.size; \
358 uint32_t idx = prod_head & mask; \
359 if (likely(idx + n < size)) { \
360 for (i = 0; i < (n & ((~(unsigned)0x3))); i+=4, idx+=4) { \
361 r->ring[idx] = obj_table[i]; \
362 r->ring[idx+1] = obj_table[i+1]; \
363 r->ring[idx+2] = obj_table[i+2]; \
364 r->ring[idx+3] = obj_table[i+3]; \
367 case 3: r->ring[idx++] = obj_table[i++]; \
368 case 2: r->ring[idx++] = obj_table[i++]; \
369 case 1: r->ring[idx++] = obj_table[i++]; \
372 for (i = 0; idx < size; i++, idx++)\
373 r->ring[idx] = obj_table[i]; \
374 for (idx = 0; i < n; i++, idx++) \
375 r->ring[idx] = obj_table[i]; \
379 /* the actual copy of pointers on the ring to obj_table.
380 * Placed here since identical code needed in both
381 * single and multi consumer dequeue functions */
382 #define DEQUEUE_PTRS() do { \
383 uint32_t idx = cons_head & mask; \
384 const uint32_t size = r->cons.size; \
385 if (likely(idx + n < size)) { \
386 for (i = 0; i < (n & (~(unsigned)0x3)); i+=4, idx+=4) {\
387 obj_table[i] = r->ring[idx]; \
388 obj_table[i+1] = r->ring[idx+1]; \
389 obj_table[i+2] = r->ring[idx+2]; \
390 obj_table[i+3] = r->ring[idx+3]; \
393 case 3: obj_table[i++] = r->ring[idx++]; \
394 case 2: obj_table[i++] = r->ring[idx++]; \
395 case 1: obj_table[i++] = r->ring[idx++]; \
398 for (i = 0; idx < size; i++, idx++) \
399 obj_table[i] = r->ring[idx]; \
400 for (idx = 0; i < n; i++, idx++) \
401 obj_table[i] = r->ring[idx]; \
406 * @internal Enqueue several objects on the ring (multi-producers safe).
408 * This function uses a "compare and set" instruction to move the
409 * producer index atomically.
412 * A pointer to the ring structure.
414 * A pointer to a table of void * pointers (objects).
416 * The number of objects to add in the ring from the obj_table.
418 * RTE_RING_QUEUE_FIXED: Enqueue a fixed number of items from a ring
419 * RTE_RING_QUEUE_VARIABLE: Enqueue as many items a possible from ring
421 * Depend on the behavior value
422 * if behavior = RTE_RING_QUEUE_FIXED
423 * - 0: Success; objects enqueue.
424 * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
425 * high water mark is exceeded.
426 * - -ENOBUFS: Not enough room in the ring to enqueue, no object is enqueued.
427 * if behavior = RTE_RING_QUEUE_VARIABLE
428 * - n: Actual number of objects enqueued.
430 static inline int __attribute__((always_inline))
431 __rte_ring_mp_do_enqueue(struct rte_ring *r, void * const *obj_table,
432 unsigned n, enum rte_ring_queue_behavior behavior)
434 uint32_t prod_head, prod_next;
435 uint32_t cons_tail, free_entries;
436 const unsigned max = n;
439 uint32_t mask = r->prod.mask;
442 /* Avoid the unnecessary cmpset operation below, which is also
443 * potentially harmful when n equals 0. */
447 /* move prod.head atomically */
449 /* Reset n to the initial burst count */
452 prod_head = r->prod.head;
454 /* add rmb barrier to avoid load/load reorder in weak
455 * memory model. It is noop on x86
459 cons_tail = r->cons.tail;
460 /* The subtraction is done between two unsigned 32bits value
461 * (the result is always modulo 32 bits even if we have
462 * prod_head > cons_tail). So 'free_entries' is always between 0
463 * and size(ring)-1. */
464 free_entries = (mask + cons_tail - prod_head);
466 /* check that we have enough room in ring */
467 if (unlikely(n > free_entries)) {
468 if (behavior == RTE_RING_QUEUE_FIXED) {
469 __RING_STAT_ADD(r, enq_fail, n);
473 /* No free entry available */
474 if (unlikely(free_entries == 0)) {
475 __RING_STAT_ADD(r, enq_fail, n);
483 prod_next = prod_head + n;
484 success = rte_atomic32_cmpset(&r->prod.head, prod_head,
486 } while (unlikely(success == 0));
488 /* write entries in ring */
492 /* if we exceed the watermark */
493 if (unlikely(((mask + 1) - free_entries + n) > r->prod.watermark)) {
494 ret = (behavior == RTE_RING_QUEUE_FIXED) ? -EDQUOT :
495 (int)(n | RTE_RING_QUOT_EXCEED);
496 __RING_STAT_ADD(r, enq_quota, n);
499 ret = (behavior == RTE_RING_QUEUE_FIXED) ? 0 : n;
500 __RING_STAT_ADD(r, enq_success, n);
504 * If there are other enqueues in progress that preceded us,
505 * we need to wait for them to complete
507 while (unlikely(r->prod.tail != prod_head)) {
510 /* Set RTE_RING_PAUSE_REP_COUNT to avoid spin too long waiting
511 * for other thread finish. It gives pre-empted thread a chance
512 * to proceed and finish with ring dequeue operation. */
513 if (RTE_RING_PAUSE_REP_COUNT &&
514 ++rep == RTE_RING_PAUSE_REP_COUNT) {
519 r->prod.tail = prod_next;
524 * @internal Enqueue several objects on a ring (NOT multi-producers safe).
527 * A pointer to the ring structure.
529 * A pointer to a table of void * pointers (objects).
531 * The number of objects to add in the ring from the obj_table.
533 * RTE_RING_QUEUE_FIXED: Enqueue a fixed number of items from a ring
534 * RTE_RING_QUEUE_VARIABLE: Enqueue as many items a possible from ring
536 * Depend on the behavior value
537 * if behavior = RTE_RING_QUEUE_FIXED
538 * - 0: Success; objects enqueue.
539 * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
540 * high water mark is exceeded.
541 * - -ENOBUFS: Not enough room in the ring to enqueue, no object is enqueued.
542 * if behavior = RTE_RING_QUEUE_VARIABLE
543 * - n: Actual number of objects enqueued.
545 static inline int __attribute__((always_inline))
546 __rte_ring_sp_do_enqueue(struct rte_ring *r, void * const *obj_table,
547 unsigned n, enum rte_ring_queue_behavior behavior)
549 uint32_t prod_head, cons_tail;
550 uint32_t prod_next, free_entries;
552 uint32_t mask = r->prod.mask;
555 prod_head = r->prod.head;
556 cons_tail = r->cons.tail;
557 /* The subtraction is done between two unsigned 32bits value
558 * (the result is always modulo 32 bits even if we have
559 * prod_head > cons_tail). So 'free_entries' is always between 0
560 * and size(ring)-1. */
561 free_entries = mask + cons_tail - prod_head;
563 /* check that we have enough room in ring */
564 if (unlikely(n > free_entries)) {
565 if (behavior == RTE_RING_QUEUE_FIXED) {
566 __RING_STAT_ADD(r, enq_fail, n);
570 /* No free entry available */
571 if (unlikely(free_entries == 0)) {
572 __RING_STAT_ADD(r, enq_fail, n);
580 prod_next = prod_head + n;
581 r->prod.head = prod_next;
583 /* write entries in ring */
587 /* if we exceed the watermark */
588 if (unlikely(((mask + 1) - free_entries + n) > r->prod.watermark)) {
589 ret = (behavior == RTE_RING_QUEUE_FIXED) ? -EDQUOT :
590 (int)(n | RTE_RING_QUOT_EXCEED);
591 __RING_STAT_ADD(r, enq_quota, n);
594 ret = (behavior == RTE_RING_QUEUE_FIXED) ? 0 : n;
595 __RING_STAT_ADD(r, enq_success, n);
598 r->prod.tail = prod_next;
603 * @internal Dequeue several objects from a ring (multi-consumers safe). When
604 * the request objects are more than the available objects, only dequeue the
605 * actual number of objects
607 * This function uses a "compare and set" instruction to move the
608 * consumer index atomically.
611 * A pointer to the ring structure.
613 * A pointer to a table of void * pointers (objects) that will be filled.
615 * The number of objects to dequeue from the ring to the obj_table.
617 * RTE_RING_QUEUE_FIXED: Dequeue a fixed number of items from a ring
618 * RTE_RING_QUEUE_VARIABLE: Dequeue as many items a possible from ring
620 * Depend on the behavior value
621 * if behavior = RTE_RING_QUEUE_FIXED
622 * - 0: Success; objects dequeued.
623 * - -ENOENT: Not enough entries in the ring to dequeue; no object is
625 * if behavior = RTE_RING_QUEUE_VARIABLE
626 * - n: Actual number of objects dequeued.
629 static inline int __attribute__((always_inline))
630 __rte_ring_mc_do_dequeue(struct rte_ring *r, void **obj_table,
631 unsigned n, enum rte_ring_queue_behavior behavior)
633 uint32_t cons_head, prod_tail;
634 uint32_t cons_next, entries;
635 const unsigned max = n;
638 uint32_t mask = r->prod.mask;
640 /* Avoid the unnecessary cmpset operation below, which is also
641 * potentially harmful when n equals 0. */
645 /* move cons.head atomically */
647 /* Restore n as it may change every loop */
650 cons_head = r->cons.head;
652 /* add rmb barrier to avoid load/load reorder in weak
653 * memory model. It is noop on x86
657 prod_tail = r->prod.tail;
658 /* The subtraction is done between two unsigned 32bits value
659 * (the result is always modulo 32 bits even if we have
660 * cons_head > prod_tail). So 'entries' is always between 0
661 * and size(ring)-1. */
662 entries = (prod_tail - cons_head);
664 /* Set the actual entries for dequeue */
666 if (behavior == RTE_RING_QUEUE_FIXED) {
667 __RING_STAT_ADD(r, deq_fail, n);
671 if (unlikely(entries == 0)){
672 __RING_STAT_ADD(r, deq_fail, n);
680 cons_next = cons_head + n;
681 success = rte_atomic32_cmpset(&r->cons.head, cons_head,
683 } while (unlikely(success == 0));
690 * If there are other dequeues in progress that preceded us,
691 * we need to wait for them to complete
693 while (unlikely(r->cons.tail != cons_head)) {
696 /* Set RTE_RING_PAUSE_REP_COUNT to avoid spin too long waiting
697 * for other thread finish. It gives pre-empted thread a chance
698 * to proceed and finish with ring dequeue operation. */
699 if (RTE_RING_PAUSE_REP_COUNT &&
700 ++rep == RTE_RING_PAUSE_REP_COUNT) {
705 __RING_STAT_ADD(r, deq_success, n);
706 r->cons.tail = cons_next;
708 return behavior == RTE_RING_QUEUE_FIXED ? 0 : n;
712 * @internal Dequeue several objects from a ring (NOT multi-consumers safe).
713 * When the request objects are more than the available objects, only dequeue
714 * the actual number of objects
717 * A pointer to the ring structure.
719 * A pointer to a table of void * pointers (objects) that will be filled.
721 * The number of objects to dequeue from the ring to the obj_table.
723 * RTE_RING_QUEUE_FIXED: Dequeue a fixed number of items from a ring
724 * RTE_RING_QUEUE_VARIABLE: Dequeue as many items a possible from ring
726 * Depend on the behavior value
727 * if behavior = RTE_RING_QUEUE_FIXED
728 * - 0: Success; objects dequeued.
729 * - -ENOENT: Not enough entries in the ring to dequeue; no object is
731 * if behavior = RTE_RING_QUEUE_VARIABLE
732 * - n: Actual number of objects dequeued.
734 static inline int __attribute__((always_inline))
735 __rte_ring_sc_do_dequeue(struct rte_ring *r, void **obj_table,
736 unsigned n, enum rte_ring_queue_behavior behavior)
738 uint32_t cons_head, prod_tail;
739 uint32_t cons_next, entries;
741 uint32_t mask = r->prod.mask;
743 cons_head = r->cons.head;
744 prod_tail = r->prod.tail;
745 /* The subtraction is done between two unsigned 32bits value
746 * (the result is always modulo 32 bits even if we have
747 * cons_head > prod_tail). So 'entries' is always between 0
748 * and size(ring)-1. */
749 entries = prod_tail - cons_head;
752 if (behavior == RTE_RING_QUEUE_FIXED) {
753 __RING_STAT_ADD(r, deq_fail, n);
757 if (unlikely(entries == 0)){
758 __RING_STAT_ADD(r, deq_fail, n);
766 cons_next = cons_head + n;
767 r->cons.head = cons_next;
773 __RING_STAT_ADD(r, deq_success, n);
774 r->cons.tail = cons_next;
775 return behavior == RTE_RING_QUEUE_FIXED ? 0 : n;
779 * Enqueue several objects on the ring (multi-producers safe).
781 * This function uses a "compare and set" instruction to move the
782 * producer index atomically.
785 * A pointer to the ring structure.
787 * A pointer to a table of void * pointers (objects).
789 * The number of objects to add in the ring from the obj_table.
791 * - 0: Success; objects enqueue.
792 * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
793 * high water mark is exceeded.
794 * - -ENOBUFS: Not enough room in the ring to enqueue, no object is enqueued.
796 static inline int __attribute__((always_inline))
797 rte_ring_mp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
800 return __rte_ring_mp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
804 * Enqueue several objects on a ring (NOT multi-producers safe).
807 * A pointer to the ring structure.
809 * A pointer to a table of void * pointers (objects).
811 * The number of objects to add in the ring from the obj_table.
813 * - 0: Success; objects enqueued.
814 * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
815 * high water mark is exceeded.
816 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
818 static inline int __attribute__((always_inline))
819 rte_ring_sp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
822 return __rte_ring_sp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
826 * Enqueue several objects on a ring.
828 * This function calls the multi-producer or the single-producer
829 * version depending on the default behavior that was specified at
830 * ring creation time (see flags).
833 * A pointer to the ring structure.
835 * A pointer to a table of void * pointers (objects).
837 * The number of objects to add in the ring from the obj_table.
839 * - 0: Success; objects enqueued.
840 * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
841 * high water mark is exceeded.
842 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
844 static inline int __attribute__((always_inline))
845 rte_ring_enqueue_bulk(struct rte_ring *r, void * const *obj_table,
848 if (r->prod.sp_enqueue)
849 return rte_ring_sp_enqueue_bulk(r, obj_table, n);
851 return rte_ring_mp_enqueue_bulk(r, obj_table, n);
855 * Enqueue one object on a ring (multi-producers safe).
857 * This function uses a "compare and set" instruction to move the
858 * producer index atomically.
861 * A pointer to the ring structure.
863 * A pointer to the object to be added.
865 * - 0: Success; objects enqueued.
866 * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
867 * high water mark is exceeded.
868 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
870 static inline int __attribute__((always_inline))
871 rte_ring_mp_enqueue(struct rte_ring *r, void *obj)
873 return rte_ring_mp_enqueue_bulk(r, &obj, 1);
877 * Enqueue one object on a ring (NOT multi-producers safe).
880 * A pointer to the ring structure.
882 * A pointer to the object to be added.
884 * - 0: Success; objects enqueued.
885 * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
886 * high water mark is exceeded.
887 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
889 static inline int __attribute__((always_inline))
890 rte_ring_sp_enqueue(struct rte_ring *r, void *obj)
892 return rte_ring_sp_enqueue_bulk(r, &obj, 1);
896 * Enqueue one object on a ring.
898 * This function calls the multi-producer or the single-producer
899 * version, depending on the default behaviour that was specified at
900 * ring creation time (see flags).
903 * A pointer to the ring structure.
905 * A pointer to the object to be added.
907 * - 0: Success; objects enqueued.
908 * - -EDQUOT: Quota exceeded. The objects have been enqueued, but the
909 * high water mark is exceeded.
910 * - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.
912 static inline int __attribute__((always_inline))
913 rte_ring_enqueue(struct rte_ring *r, void *obj)
915 if (r->prod.sp_enqueue)
916 return rte_ring_sp_enqueue(r, obj);
918 return rte_ring_mp_enqueue(r, obj);
922 * Dequeue several objects from a ring (multi-consumers safe).
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 * - 0: Success; objects dequeued.
935 * - -ENOENT: Not enough entries in the ring to dequeue; no object is
938 static inline int __attribute__((always_inline))
939 rte_ring_mc_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
941 return __rte_ring_mc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
945 * Dequeue several objects from a ring (NOT multi-consumers safe).
948 * A pointer to the ring structure.
950 * A pointer to a table of void * pointers (objects) that will be filled.
952 * The number of objects to dequeue from the ring to the obj_table,
953 * must be strictly positive.
955 * - 0: Success; objects dequeued.
956 * - -ENOENT: Not enough entries in the ring to dequeue; no object is
959 static inline int __attribute__((always_inline))
960 rte_ring_sc_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
962 return __rte_ring_sc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED);
966 * Dequeue several objects from a ring.
968 * This function calls the multi-consumers or the single-consumer
969 * version, depending on the default behaviour that was specified at
970 * ring creation time (see flags).
973 * A pointer to the ring structure.
975 * A pointer to a table of void * pointers (objects) that will be filled.
977 * The number of objects to dequeue from the ring to the obj_table.
979 * - 0: Success; objects dequeued.
980 * - -ENOENT: Not enough entries in the ring to dequeue, no object is
983 static inline int __attribute__((always_inline))
984 rte_ring_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned n)
986 if (r->cons.sc_dequeue)
987 return rte_ring_sc_dequeue_bulk(r, obj_table, n);
989 return rte_ring_mc_dequeue_bulk(r, obj_table, n);
993 * Dequeue one object from a ring (multi-consumers safe).
995 * This function uses a "compare and set" instruction to move the
996 * consumer index atomically.
999 * A pointer to the ring structure.
1001 * A pointer to a void * pointer (object) that will be filled.
1003 * - 0: Success; objects dequeued.
1004 * - -ENOENT: Not enough entries in the ring to dequeue; no object is
1007 static inline int __attribute__((always_inline))
1008 rte_ring_mc_dequeue(struct rte_ring *r, void **obj_p)
1010 return rte_ring_mc_dequeue_bulk(r, obj_p, 1);
1014 * Dequeue one object from a ring (NOT multi-consumers safe).
1017 * A pointer to the ring structure.
1019 * A pointer to a void * pointer (object) that will be filled.
1021 * - 0: Success; objects dequeued.
1022 * - -ENOENT: Not enough entries in the ring to dequeue, no object is
1025 static inline int __attribute__((always_inline))
1026 rte_ring_sc_dequeue(struct rte_ring *r, void **obj_p)
1028 return rte_ring_sc_dequeue_bulk(r, obj_p, 1);
1032 * Dequeue one object from a ring.
1034 * This function calls the multi-consumers or the single-consumer
1035 * version depending on the default behaviour that was specified at
1036 * ring creation time (see flags).
1039 * A pointer to the ring structure.
1041 * A pointer to a void * pointer (object) that will be filled.
1043 * - 0: Success, objects dequeued.
1044 * - -ENOENT: Not enough entries in the ring to dequeue, no object is
1047 static inline int __attribute__((always_inline))
1048 rte_ring_dequeue(struct rte_ring *r, void **obj_p)
1050 if (r->cons.sc_dequeue)
1051 return rte_ring_sc_dequeue(r, obj_p);
1053 return rte_ring_mc_dequeue(r, obj_p);
1057 * Test if a ring is full.
1060 * A pointer to the ring structure.
1062 * - 1: The ring is full.
1063 * - 0: The ring is not full.
1066 rte_ring_full(const struct rte_ring *r)
1068 uint32_t prod_tail = r->prod.tail;
1069 uint32_t cons_tail = r->cons.tail;
1070 return ((cons_tail - prod_tail - 1) & r->prod.mask) == 0;
1074 * Test if a ring is empty.
1077 * A pointer to the ring structure.
1079 * - 1: The ring is empty.
1080 * - 0: The ring is not empty.
1083 rte_ring_empty(const struct rte_ring *r)
1085 uint32_t prod_tail = r->prod.tail;
1086 uint32_t cons_tail = r->cons.tail;
1087 return !!(cons_tail == prod_tail);
1091 * Return the number of entries in a ring.
1094 * A pointer to the ring structure.
1096 * The number of entries in the ring.
1098 static inline unsigned
1099 rte_ring_count(const struct rte_ring *r)
1101 uint32_t prod_tail = r->prod.tail;
1102 uint32_t cons_tail = r->cons.tail;
1103 return (prod_tail - cons_tail) & r->prod.mask;
1107 * Return the number of free entries in a ring.
1110 * A pointer to the ring structure.
1112 * The number of free entries in the ring.
1114 static inline unsigned
1115 rte_ring_free_count(const struct rte_ring *r)
1117 uint32_t prod_tail = r->prod.tail;
1118 uint32_t cons_tail = r->cons.tail;
1119 return (cons_tail - prod_tail - 1) & r->prod.mask;
1123 * Dump the status of all rings on the console
1126 * A pointer to a file for output
1128 void rte_ring_list_dump(FILE *f);
1131 * Search a ring from its name
1134 * The name of the ring.
1136 * The pointer to the ring matching the name, or NULL if not found,
1137 * with rte_errno set appropriately. Possible rte_errno values include:
1138 * - ENOENT - required entry not available to return.
1140 struct rte_ring *rte_ring_lookup(const char *name);
1143 * Enqueue several objects on the ring (multi-producers safe).
1145 * This function uses a "compare and set" instruction to move the
1146 * producer index atomically.
1149 * A pointer to the ring structure.
1151 * A pointer to a table of void * pointers (objects).
1153 * The number of objects to add in the ring from the obj_table.
1155 * - n: Actual number of objects enqueued.
1157 static inline unsigned __attribute__((always_inline))
1158 rte_ring_mp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
1161 return __rte_ring_mp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
1165 * Enqueue several objects on a ring (NOT multi-producers safe).
1168 * A pointer to the ring structure.
1170 * A pointer to a table of void * pointers (objects).
1172 * The number of objects to add in the ring from the obj_table.
1174 * - n: Actual number of objects enqueued.
1176 static inline unsigned __attribute__((always_inline))
1177 rte_ring_sp_enqueue_burst(struct rte_ring *r, void * const *obj_table,
1180 return __rte_ring_sp_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
1184 * Enqueue several objects on a ring.
1186 * This function calls the multi-producer or the single-producer
1187 * version depending on the default behavior that was specified at
1188 * ring creation time (see flags).
1191 * A pointer to the ring structure.
1193 * A pointer to a table of void * pointers (objects).
1195 * The number of objects to add in the ring from the obj_table.
1197 * - n: Actual number of objects enqueued.
1199 static inline unsigned __attribute__((always_inline))
1200 rte_ring_enqueue_burst(struct rte_ring *r, void * const *obj_table,
1203 if (r->prod.sp_enqueue)
1204 return rte_ring_sp_enqueue_burst(r, obj_table, n);
1206 return rte_ring_mp_enqueue_burst(r, obj_table, n);
1210 * Dequeue several objects from a ring (multi-consumers safe). When the request
1211 * objects are more than the available objects, only dequeue the actual number
1214 * This function uses a "compare and set" instruction to move the
1215 * consumer index atomically.
1218 * A pointer to the ring structure.
1220 * A pointer to a table of void * pointers (objects) that will be filled.
1222 * The number of objects to dequeue from the ring to the obj_table.
1224 * - n: Actual number of objects dequeued, 0 if ring is empty
1226 static inline unsigned __attribute__((always_inline))
1227 rte_ring_mc_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
1229 return __rte_ring_mc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
1233 * Dequeue several objects from a ring (NOT multi-consumers safe).When the
1234 * request objects are more than the available objects, only dequeue the
1235 * actual number of objects
1238 * A pointer to the ring structure.
1240 * A pointer to a table of void * pointers (objects) that will be filled.
1242 * The number of objects to dequeue from the ring to the obj_table.
1244 * - n: Actual number of objects dequeued, 0 if ring is empty
1246 static inline unsigned __attribute__((always_inline))
1247 rte_ring_sc_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
1249 return __rte_ring_sc_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE);
1253 * Dequeue multiple objects from a ring up to a maximum number.
1255 * This function calls the multi-consumers or the single-consumer
1256 * version, depending on the default behaviour that was specified at
1257 * ring creation time (see flags).
1260 * A pointer to the ring structure.
1262 * A pointer to a table of void * pointers (objects) that will be filled.
1264 * The number of objects to dequeue from the ring to the obj_table.
1266 * - Number of objects dequeued
1268 static inline unsigned __attribute__((always_inline))
1269 rte_ring_dequeue_burst(struct rte_ring *r, void **obj_table, unsigned n)
1271 if (r->cons.sc_dequeue)
1272 return rte_ring_sc_dequeue_burst(r, obj_table, n);
1274 return rte_ring_mc_dequeue_burst(r, obj_table, n);
1281 #endif /* _RTE_RING_H_ */