rte_ring.h

/*-*   BSD LICENSE**   Copyright(c) 2010-2017 Intel Corporation. All rights reserved.*   All rights reserved.**   Redistribution and use in source and binary forms, with or without*   modification, are permitted provided that the following conditions*   are met:**     * Redistributions of source code must retain the above copyright*       notice, this list of conditions and the following disclaimer.*     * Redistributions in binary form must reproduce the above copyright*       notice, this list of conditions and the following disclaimer in*       the documentation and/or other materials provided with the*       distribution.*     * Neither the name of Intel Corporation nor the names of its*       contributors may be used to endorse or promote products derived*       from this software without specific prior written permission.**   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS*   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT*   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR*   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT*   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,*   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT*   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,*   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY*   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT*   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE*   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.*//** Derived from FreeBSD's bufring.h***************************************************************************** Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org* All rights reserved.** Redistribution and use in source and binary forms, with or without* modification, are permitted provided that the following conditions are met:** 1. Redistributions of source code must retain the above copyright notice,*    this list of conditions and the following disclaimer.** 2. The name of Kip Macy nor the names of other*    contributors may be used to endorse or promote products derived from*    this software without specific prior written permission.** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE* POSSIBILITY OF SUCH DAMAGE.****************************************************************************/#ifndef _RTE_RING_H_
#define _RTE_RING_H_/*** @file* RTE Ring** The Ring Manager is a fixed-size queue, implemented as a table of* pointers. Head and tail pointers are modified atomically, allowing* concurrent access to it. It has the following features:** - FIFO (First In First Out)* - Maximum size is fixed; the pointers are stored in a table.* - Lockless implementation.* - Multi- or single-consumer dequeue.* - Multi- or single-producer enqueue.* - Bulk dequeue.* - Bulk enqueue.** Note: the ring implementation is not preemptable. A lcore must not* be interrupted by another task that uses the same ring.**/#ifdef __cplusplus
extern "C" {
#endif#include <stdio.h>
#include <stdint.h>
#include <sys/queue.h>
#include <errno.h>
#include <xmmintrin.h>#ifndef RTE_ATOMIC_H
#define RTE_ATOMIC_H/*** Compiler barrier.** Guarantees that operation reordering does not occur at compile time* for operations directly before and after the barrier.*/
#define rte_compiler_barrier() do {     \asm volatile ("" : : : "memory");  \
} while(0)#define MPLOCKED        "lock ; "
/*------------------------- 32 bit atomic operations -------------------------*/
static inline int
rte_atomic32_cmpset(volatile uint32_t *dst, uint32_t exp, uint32_t src)
{uint8_t res;asm volatile(MPLOCKED"cmpxchgl %[src], %[dst];""sete %[res];": [res] "=a" (res),     /* output */[dst] "=m" (*dst): [src] "r" (src),      /* input */"a" (exp),"m" (*dst): "memory");            /* no-clobber list */return res;
}#define rte_smp_wmb() rte_compiler_barrier()#define rte_smp_rmb() rte_compiler_barrier()#endif#define  __rte_always_inline inline#define RTE_RING_MZ_PREFIX "RG_"enum rte_ring_queue_behavior {RTE_RING_QUEUE_FIXED = 0, /* Enq/Deq a fixed number of items from a ring */RTE_RING_QUEUE_VARIABLE   /* Enq/Deq as many items as possible from ring */
};
/* structure to hold a pair of head/tail values and other metadata */
struct rte_ring_headtail {volatile uint32_t head;  /**< Prod/consumer head. */volatile uint32_t tail;  /**< Prod/consumer tail. */uint32_t single;         /**< True if single prod/cons */
};
#define  RTE_NAMESIZE 256
/*** An RTE ring structure.** The producer and the consumer have a head and a tail index. The particularity* of these index is that they are not between 0 and size(ring). These indexes* are between 0 and 2^32, and we mask their value when we access the ring[]* field. Thanks to this assumption, we can do subtractions between 2 index* values in a modulo-32bit base: that's why the overflow of the indexes is not* a problem.*/
struct rte_ring {/** Note: this field kept the RTE_MEMZONE_NAMESIZE size due to ABI* compatibility requirements, it could be changed to RTE_RING_NAMESIZE* next time the ABI changes*/char name[RTE_NAMESIZE];int flags;               /**< Flags supplied at creation. *//**< Memzone, if any, containing the rte_ring */uint32_t size;           /**< Size of ring. */uint32_t mask;           /**< Mask (size-1) of ring. */uint32_t capacity;       /**< Usable size of ring *//** Ring producer status. */struct rte_ring_headtail prod;/** Ring consumer status. */struct rte_ring_headtail cons;
};#define RING_F_SP_ENQ 0x0001 /**< The default enqueue is "single-producer". */
#define RING_F_SC_DEQ 0x0002 /**< The default dequeue is "single-consumer". */
/*** Ring is to hold exactly requested number of entries.* Without this flag set, the ring size requested must be a power of 2, and the* usable space will be that size - 1. With the flag, the requested size will* be rounded up to the next power of two, but the usable space will be exactly* that requested. Worst case, if a power-of-2 size is requested, half the* ring space will be wasted.*/
#define RING_F_EXACT_SZ 0x0004
#define RTE_RING_SZ_MASK  (unsigned)(0x0fffffff) /**< Ring size mask *//* @internal defines for passing to the enqueue dequeue worker functions */
#define __IS_SP 1
#define __IS_MP 0
#define __IS_SC 1
#define __IS_MC 0static inline uint32_t
rte_align32pow2(uint32_t x)
{x--;x |= x >> 1;x |= x >> 2;x |= x >> 4;x |= x >> 8;x |= x >> 16;return x + 1;
}/*** Calculate the memory size needed for a ring** This function returns the number of bytes needed for a ring, given* the number of elements in it. This value is the sum of the size of* the structure rte_ring and the size of the memory needed by the* objects pointers. The value is aligned to a cache line size.** @param count*   The number of elements in the ring (must be a power of 2).* @return*   - The memory size needed for the ring on success.*   - -EINVAL if count is not a power of 2.*/
ssize_t rte_ring_get_memsize(unsigned count);/*** Initialize a ring structure.** Initialize a ring structure in memory pointed by "r". The size of the* memory area must be large enough to store the ring structure and the* object table. It is advised to use rte_ring_get_memsize() to get the* appropriate size.** The ring size is set to *count*, which must be a power of two. Water* marking is disabled by default. The real usable ring size is* *count-1* instead of *count* to differentiate a free ring from an* empty ring.** The ring is not added in RTE_TAILQ_RING global list. Indeed, the* memory given by the caller may not be shareable among dpdk* processes.** @param r*   The pointer to the ring structure followed by the objects table.* @param name*   The name of the ring.* @param count*   The number of elements in the ring (must be a power of 2).* @param flags*   An OR of the following:*    - RING_F_SP_ENQ: If this flag is set, the default behavior when*      using ``rte_ring_enqueue()`` or ``rte_ring_enqueue_bulk()``*      is "single-producer". Otherwise, it is "multi-producers".*    - RING_F_SC_DEQ: If this flag is set, the default behavior when*      using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``*      is "single-consumer". Otherwise, it is "multi-consumers".* @return*   0 on success, or a negative value on error.*/
int rte_ring_init(struct rte_ring *r, const char *name, unsigned count,unsigned flags);/*** Create a new ring named *name* in memory.** This function uses ``memzone_reserve()`` to allocate memory. Then it* calls rte_ring_init() to initialize an empty ring.** The new ring size is set to *count*, which must be a power of* two. Water marking is disabled by default. The real usable ring size* is *count-1* instead of *count* to differentiate a free ring from an* empty ring.** The ring is added in RTE_TAILQ_RING list.** @param name*   The name of the ring.* @param count*   The size of the ring (must be a power of 2).* @param socket_id*   The *socket_id* argument is the socket identifier in case of*   NUMA. The value can be *SOCKET_ID_ANY* if there is no NUMA*   constraint for the reserved zone.* @param flags*   An OR of the following:*    - RING_F_SP_ENQ: If this flag is set, the default behavior when*      using ``rte_ring_enqueue()`` or ``rte_ring_enqueue_bulk()``*      is "single-producer". Otherwise, it is "multi-producers".*    - RING_F_SC_DEQ: If this flag is set, the default behavior when*      using ``rte_ring_dequeue()`` or ``rte_ring_dequeue_bulk()``*      is "single-consumer". Otherwise, it is "multi-consumers".* @return*   On success, the pointer to the new allocated ring. NULL on error with*    rte_errno set appropriately. Possible errno values include:*    - E_RTE_NO_CONFIG - function could not get pointer to rte_config structure*    - E_RTE_SECONDARY - function was called from a secondary process instance*    - EINVAL - count provided is not a power of 2*    - ENOSPC - the maximum number of memzones has already been allocated*    - EEXIST - a memzone with the same name already exists*    - ENOMEM - no appropriate memory area found in which to create memzone*/
struct rte_ring *rte_ring_create(const char *name, unsigned count,unsigned flags);
/*** De-allocate all memory used by the ring.** @param r*   Ring to free*/
void rte_ring_free(struct rte_ring *r);/*** Dump the status of the ring to a file.** @param f*   A pointer to a file for output* @param r*   A pointer to the ring structure.*/
void rte_ring_dump(FILE *f, const struct rte_ring *r);/* the actual enqueue of pointers on the ring.* Placed here since identical code needed in both* single and multi producer enqueue functions */
#define ENQUEUE_PTRS(r, ring_start, prod_head, obj_table, n, obj_type) do { \unsigned int i; \const uint32_t size = (r)->size; \uint32_t idx = prod_head & (r)->mask; \obj_type *ring = (obj_type *)ring_start; \if (idx + n < size) { \for (i = 0; i < (n & ((~(unsigned)0x3))); i+=4, idx+=4) { \ring[idx] = obj_table[i]; \ring[idx+1] = obj_table[i+1]; \ring[idx+2] = obj_table[i+2]; \ring[idx+3] = obj_table[i+3]; \} \switch (n & 0x3) { \case 3: \ring[idx++] = obj_table[i++]; /* fallthrough */ \case 2: \ring[idx++] = obj_table[i++]; /* fallthrough */ \case 1: \ring[idx++] = obj_table[i++]; \} \} else { \for (i = 0; idx < size; i++, idx++)\ring[idx] = obj_table[i]; \for (idx = 0; i < n; i++, idx++) \ring[idx] = obj_table[i]; \} \
} while (0)/* the actual copy of pointers on the ring to obj_table.* Placed here since identical code needed in both* single and multi consumer dequeue functions */
#define DEQUEUE_PTRS(r, ring_start, cons_head, obj_table, n, obj_type) do { \unsigned int i; \uint32_t idx = cons_head & (r)->mask; \const uint32_t size = (r)->size; \obj_type *ring = (obj_type *)ring_start; \if (idx + n < size) { \for (i = 0; i < (n & (~(unsigned)0x3)); i+=4, idx+=4) {\obj_table[i] = ring[idx]; \obj_table[i+1] = ring[idx+1]; \obj_table[i+2] = ring[idx+2]; \obj_table[i+3] = ring[idx+3]; \} \switch (n & 0x3) { \case 3: \obj_table[i++] = ring[idx++]; /* fallthrough */ \case 2: \obj_table[i++] = ring[idx++]; /* fallthrough */ \case 1: \obj_table[i++] = ring[idx++]; \} \} else { \for (i = 0; idx < size; i++, idx++) \obj_table[i] = ring[idx]; \for (idx = 0; i < n; i++, idx++) \obj_table[i] = ring[idx]; \} \
} while (0)static __rte_always_inline void
update_tail(struct rte_ring_headtail *ht, uint32_t old_val, uint32_t new_val,uint32_t single)
{/** If there are other enqueues/dequeues in progress that preceded us,* we need to wait for them to complete*/if (!single)while (ht->tail != old_val)_mm_pause();ht->tail = new_val;
}/*** @internal This function updates the producer head for enqueue** @param r*   A pointer to the ring structure* @param is_sp*   Indicates whether multi-producer path is needed or not* @param n*   The number of elements we will want to enqueue, i.e. how far should the*   head be moved* @param behavior*   RTE_RING_QUEUE_FIXED:    Enqueue a fixed number of items from a ring*   RTE_RING_QUEUE_VARIABLE: Enqueue as many items as possible from ring* @param old_head*   Returns head value as it was before the move, i.e. where enqueue starts* @param new_head*   Returns the current/new head value i.e. where enqueue finishes* @param free_entries*   Returns the amount of free space in the ring BEFORE head was moved* @return*   Actual number of objects enqueued.*   If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.*/
static __rte_always_inline unsigned int
__rte_ring_move_prod_head(struct rte_ring *r, int is_sp,unsigned int n, enum rte_ring_queue_behavior behavior,uint32_t *old_head, uint32_t *new_head,uint32_t *free_entries)
{const uint32_t capacity = r->capacity;unsigned int max = n;int success;do {/* Reset n to the initial burst count */n = max;*old_head = r->prod.head;const uint32_t cons_tail = r->cons.tail;/**  The subtraction is done between two unsigned 32bits value* (the result is always modulo 32 bits even if we have* *old_head > cons_tail). So 'free_entries' is always between 0* and capacity (which is < size).*/*free_entries = (capacity + cons_tail - *old_head);/* check that we have enough room in ring */if (n > *free_entries)n = (behavior == RTE_RING_QUEUE_FIXED) ?0 : *free_entries;if (n == 0)return 0;*new_head = *old_head + n;if (is_sp)r->prod.head = *new_head, success = 1;elsesuccess = rte_atomic32_cmpset(&r->prod.head,*old_head, *new_head);} while (success == 0);return n;
}/*** @internal Enqueue several objects on the ring** @param r*   A pointer to the ring structure.* @param obj_table*   A pointer to a table of void * pointers (objects).* @param n*   The number of objects to add in the ring from the obj_table.* @param behavior*   RTE_RING_QUEUE_FIXED:    Enqueue a fixed number of items from a ring*   RTE_RING_QUEUE_VARIABLE: Enqueue as many items as possible from ring* @param is_sp*   Indicates whether to use single producer or multi-producer head update* @param free_space*   returns the amount of space after the enqueue operation has finished* @return*   Actual number of objects enqueued.*   If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.*/
static __rte_always_inline unsigned int
__rte_ring_do_enqueue(struct rte_ring *r, void * const *obj_table,unsigned int n, enum rte_ring_queue_behavior behavior,int is_sp, unsigned int *free_space)
{uint32_t prod_head, prod_next;uint32_t free_entries;n = __rte_ring_move_prod_head(r, is_sp, n, behavior,&prod_head, &prod_next, &free_entries);if (n == 0)goto end;ENQUEUE_PTRS(r, &r[1], prod_head, obj_table, n, void *);rte_smp_wmb();update_tail(&r->prod, prod_head, prod_next, is_sp);
end:if (free_space != NULL)*free_space = free_entries - n;return n;
}/*** @internal This function updates the consumer head for dequeue** @param r*   A pointer to the ring structure* @param is_sc*   Indicates whether multi-consumer path is needed or not* @param n*   The number of elements we will want to enqueue, i.e. how far should the*   head be moved* @param behavior*   RTE_RING_QUEUE_FIXED:    Dequeue a fixed number of items from a ring*   RTE_RING_QUEUE_VARIABLE: Dequeue as many items as possible from ring* @param old_head*   Returns head value as it was before the move, i.e. where dequeue starts* @param new_head*   Returns the current/new head value i.e. where dequeue finishes* @param entries*   Returns the number of entries in the ring BEFORE head was moved* @return*   - Actual number of objects dequeued.*     If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.*/
static __rte_always_inline unsigned int
__rte_ring_move_cons_head(struct rte_ring *r, int is_sc,unsigned int n, enum rte_ring_queue_behavior behavior,uint32_t *old_head, uint32_t *new_head,uint32_t *entries)
{unsigned int max = n;int success;/* move cons.head atomically */do {/* Restore n as it may change every loop */n = max;*old_head = r->cons.head;const uint32_t prod_tail = r->prod.tail;/* The subtraction is done between two unsigned 32bits value* (the result is always modulo 32 bits even if we have* cons_head > prod_tail). So 'entries' is always between 0* and size(ring)-1. */*entries = (prod_tail - *old_head);/* Set the actual entries for dequeue */if (n > *entries)n = (behavior == RTE_RING_QUEUE_FIXED) ? 0 : *entries;if (n == 0)return 0;*new_head = *old_head + n;if (is_sc)r->cons.head = *new_head, success = 1;elsesuccess = rte_atomic32_cmpset(&r->cons.head, *old_head,*new_head);} while (success == 0);return n;
}/*** @internal Dequeue several objects from the ring** @param r*   A pointer to the ring structure.* @param obj_table*   A pointer to a table of void * pointers (objects).* @param n*   The number of objects to pull from the ring.* @param behavior*   RTE_RING_QUEUE_FIXED:    Dequeue a fixed number of items from a ring*   RTE_RING_QUEUE_VARIABLE: Dequeue as many items as possible from ring* @param is_sc*   Indicates whether to use single consumer or multi-consumer head update* @param available*   returns the number of remaining ring entries after the dequeue has finished* @return*   - Actual number of objects dequeued.*     If behavior == RTE_RING_QUEUE_FIXED, this will be 0 or n only.*/
static __rte_always_inline unsigned int
__rte_ring_do_dequeue(struct rte_ring *r, void **obj_table,unsigned int n, enum rte_ring_queue_behavior behavior,int is_sc, unsigned int *available)
{uint32_t cons_head, cons_next;uint32_t entries;n = __rte_ring_move_cons_head(r, is_sc, n, behavior,&cons_head, &cons_next, &entries);if (n == 0)goto end;DEQUEUE_PTRS(r, &r[1], cons_head, obj_table, n, void *);rte_smp_rmb();update_tail(&r->cons, cons_head, cons_next, is_sc);end:if (available != NULL)*available = entries - n;return n;
}/*** Enqueue several objects on the ring (multi-producers safe).** This function uses a "compare and set" instruction to move the* producer index atomically.** @param r*   A pointer to the ring structure.* @param obj_table*   A pointer to a table of void * pointers (objects).* @param n*   The number of objects to add in the ring from the obj_table.* @param free_space*   if non-NULL, returns the amount of space in the ring after the*   enqueue operation has finished.* @return*   The number of objects enqueued, either 0 or n*/
static __rte_always_inline unsigned int
rte_ring_mp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,unsigned int n, unsigned int *free_space)
{return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,__IS_MP, free_space);
}/*** Enqueue several objects on a ring (NOT multi-producers safe).** @param r*   A pointer to the ring structure.* @param obj_table*   A pointer to a table of void * pointers (objects).* @param n*   The number of objects to add in the ring from the obj_table.* @param free_space*   if non-NULL, returns the amount of space in the ring after the*   enqueue operation has finished.* @return*   The number of objects enqueued, either 0 or n*/
static __rte_always_inline unsigned int
rte_ring_sp_enqueue_bulk(struct rte_ring *r, void * const *obj_table,unsigned int n, unsigned int *free_space)
{return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,__IS_SP, free_space);
}/*** Enqueue several objects on a ring.** This function calls the multi-producer or the single-producer* version depending on the default behavior that was specified at* ring creation time (see flags).** @param r*   A pointer to the ring structure.* @param obj_table*   A pointer to a table of void * pointers (objects).* @param n*   The number of objects to add in the ring from the obj_table.* @param free_space*   if non-NULL, returns the amount of space in the ring after the*   enqueue operation has finished.* @return*   The number of objects enqueued, either 0 or n*/
static __rte_always_inline unsigned int
rte_ring_enqueue_bulk(struct rte_ring *r, void * const *obj_table,unsigned int n, unsigned int *free_space)
{return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_FIXED,r->prod.single, free_space);
}/*** Enqueue one object on a ring (multi-producers safe).** This function uses a "compare and set" instruction to move the* producer index atomically.** @param r*   A pointer to the ring structure.* @param obj*   A pointer to the object to be added.* @return*   - 0: Success; objects enqueued.*   - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.*/
static __rte_always_inline int
rte_ring_mp_enqueue(struct rte_ring *r, void *obj)
{return rte_ring_mp_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
}/*** Enqueue one object on a ring (NOT multi-producers safe).** @param r*   A pointer to the ring structure.* @param obj*   A pointer to the object to be added.* @return*   - 0: Success; objects enqueued.*   - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.*/
static __rte_always_inline int
rte_ring_sp_enqueue(struct rte_ring *r, void *obj)
{return rte_ring_sp_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
}/*** Enqueue one object on a ring.** This function calls the multi-producer or the single-producer* version, depending on the default behaviour that was specified at* ring creation time (see flags).** @param r*   A pointer to the ring structure.* @param obj*   A pointer to the object to be added.* @return*   - 0: Success; objects enqueued.*   - -ENOBUFS: Not enough room in the ring to enqueue; no object is enqueued.*/
static __rte_always_inline int
rte_ring_enqueue(struct rte_ring *r, void *obj)
{return rte_ring_enqueue_bulk(r, &obj, 1, NULL) ? 0 : -ENOBUFS;
}/*** Dequeue several objects from a ring (multi-consumers safe).** This function uses a "compare and set" instruction to move the* consumer index atomically.** @param r*   A pointer to the ring structure.* @param obj_table*   A pointer to a table of void * pointers (objects) that will be filled.* @param n*   The number of objects to dequeue from the ring to the obj_table.* @param available*   If non-NULL, returns the number of remaining ring entries after the*   dequeue has finished.* @return*   The number of objects dequeued, either 0 or n*/
static __rte_always_inline unsigned int
rte_ring_mc_dequeue_bulk(struct rte_ring *r, void **obj_table,unsigned int n, unsigned int *available)
{return __rte_ring_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED,__IS_MC, available);
}/*** Dequeue several objects from a ring (NOT multi-consumers safe).** @param r*   A pointer to the ring structure.* @param obj_table*   A pointer to a table of void * pointers (objects) that will be filled.* @param n*   The number of objects to dequeue from the ring to the obj_table,*   must be strictly positive.* @param available*   If non-NULL, returns the number of remaining ring entries after the*   dequeue has finished.* @return*   The number of objects dequeued, either 0 or n*/
static __rte_always_inline unsigned int
rte_ring_sc_dequeue_bulk(struct rte_ring *r, void **obj_table,unsigned int n, unsigned int *available)
{return __rte_ring_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED,__IS_SC, available);
}/*** Dequeue several objects from a ring.** This function calls the multi-consumers or the single-consumer* version, depending on the default behaviour that was specified at* ring creation time (see flags).** @param r*   A pointer to the ring structure.* @param obj_table*   A pointer to a table of void * pointers (objects) that will be filled.* @param n*   The number of objects to dequeue from the ring to the obj_table.* @param available*   If non-NULL, returns the number of remaining ring entries after the*   dequeue has finished.* @return*   The number of objects dequeued, either 0 or n*/
static __rte_always_inline unsigned int
rte_ring_dequeue_bulk(struct rte_ring *r, void **obj_table, unsigned int n,unsigned int *available)
{return __rte_ring_do_dequeue(r, obj_table, n, RTE_RING_QUEUE_FIXED,r->cons.single, available);
}/*** Dequeue one object from a ring (multi-consumers safe).** This function uses a "compare and set" instruction to move the* consumer index atomically.** @param r*   A pointer to the ring structure.* @param obj_p*   A pointer to a void * pointer (object) that will be filled.* @return*   - 0: Success; objects dequeued.*   - -ENOENT: Not enough entries in the ring to dequeue; no object is*     dequeued.*/
static __rte_always_inline int
rte_ring_mc_dequeue(struct rte_ring *r, void **obj_p)
{return rte_ring_mc_dequeue_bulk(r, obj_p, 1, NULL)  ? 0 : -ENOENT;
}/*** Dequeue one object from a ring (NOT multi-consumers safe).** @param r*   A pointer to the ring structure.* @param obj_p*   A pointer to a void * pointer (object) that will be filled.* @return*   - 0: Success; objects dequeued.*   - -ENOENT: Not enough entries in the ring to dequeue, no object is*     dequeued.*/
static __rte_always_inline int
rte_ring_sc_dequeue(struct rte_ring *r, void **obj_p)
{return rte_ring_sc_dequeue_bulk(r, obj_p, 1, NULL) ? 0 : -ENOENT;
}/*** Dequeue one object from a ring.** This function calls the multi-consumers or the single-consumer* version depending on the default behaviour that was specified at* ring creation time (see flags).** @param r*   A pointer to the ring structure.* @param obj_p*   A pointer to a void * pointer (object) that will be filled.* @return*   - 0: Success, objects dequeued.*   - -ENOENT: Not enough entries in the ring to dequeue, no object is*     dequeued.*/
static __rte_always_inline int
rte_ring_dequeue(struct rte_ring *r, void **obj_p)
{return rte_ring_dequeue_bulk(r, obj_p, 1, NULL) ? 0 : -ENOENT;
}/*** Return the number of entries in a ring.** @param r*   A pointer to the ring structure.* @return*   The number of entries in the ring.*/
static inline unsigned
rte_ring_count(const struct rte_ring *r)
{uint32_t prod_tail = r->prod.tail;uint32_t cons_tail = r->cons.tail;uint32_t count = (prod_tail - cons_tail) & r->mask;return (count > r->capacity) ? r->capacity : count;
}/*** Return the number of free entries in a ring.** @param r*   A pointer to the ring structure.* @return*   The number of free entries in the ring.*/
static inline unsigned
rte_ring_free_count(const struct rte_ring *r)
{return r->capacity - rte_ring_count(r);
}/*** Test if a ring is full.** @param r*   A pointer to the ring structure.* @return*   - 1: The ring is full.*   - 0: The ring is not full.*/
static inline int
rte_ring_full(const struct rte_ring *r)
{return rte_ring_free_count(r) == 0;
}/*** Test if a ring is empty.** @param r*   A pointer to the ring structure.* @return*   - 1: The ring is empty.*   - 0: The ring is not empty.*/
static inline int
rte_ring_empty(const struct rte_ring *r)
{return rte_ring_count(r) == 0;
}/*** Return the size of the ring.** @param r*   A pointer to the ring structure.* @return*   The size of the data store used by the ring.*   NOTE: this is not the same as the usable space in the ring. To query that*   use ``rte_ring_get_capacity()``.*/
static inline unsigned int
rte_ring_get_size(const struct rte_ring *r)
{return r->size;
}/*** Return the number of elements which can be stored in the ring.** @param r*   A pointer to the ring structure.* @return*   The usable size of the ring.*/
static inline unsigned int
rte_ring_get_capacity(const struct rte_ring *r)
{return r->capacity;
}/*** Dump the status of all rings on the console** @param f*   A pointer to a file for output*/
void rte_ring_list_dump(FILE *f);/*** Search a ring from its name** @param name*   The name of the ring.* @return*   The pointer to the ring matching the name, or NULL if not found,*   with rte_errno set appropriately. Possible rte_errno values include:*    - ENOENT - required entry not available to return.*/
struct rte_ring *rte_ring_lookup(const char *name);/*** Enqueue several objects on the ring (multi-producers safe).** This function uses a "compare and set" instruction to move the* producer index atomically.** @param r*   A pointer to the ring structure.* @param obj_table*   A pointer to a table of void * pointers (objects).* @param n*   The number of objects to add in the ring from the obj_table.* @param free_space*   if non-NULL, returns the amount of space in the ring after the*   enqueue operation has finished.* @return*   - n: Actual number of objects enqueued.*/
static __rte_always_inline unsigned
rte_ring_mp_enqueue_burst(struct rte_ring *r, void * const *obj_table,unsigned int n, unsigned int *free_space)
{return __rte_ring_do_enqueue(r, obj_table, n,RTE_RING_QUEUE_VARIABLE, __IS_MP, free_space);
}/*** Enqueue several objects on a ring (NOT multi-producers safe).** @param r*   A pointer to the ring structure.* @param obj_table*   A pointer to a table of void * pointers (objects).* @param n*   The number of objects to add in the ring from the obj_table.* @param free_space*   if non-NULL, returns the amount of space in the ring after the*   enqueue operation has finished.* @return*   - n: Actual number of objects enqueued.*/
static __rte_always_inline unsigned
rte_ring_sp_enqueue_burst(struct rte_ring *r, void * const *obj_table,unsigned int n, unsigned int *free_space)
{return __rte_ring_do_enqueue(r, obj_table, n,RTE_RING_QUEUE_VARIABLE, __IS_SP, free_space);
}/*** Enqueue several objects on a ring.** This function calls the multi-producer or the single-producer* version depending on the default behavior that was specified at* ring creation time (see flags).** @param r*   A pointer to the ring structure.* @param obj_table*   A pointer to a table of void * pointers (objects).* @param n*   The number of objects to add in the ring from the obj_table.* @param free_space*   if non-NULL, returns the amount of space in the ring after the*   enqueue operation has finished.* @return*   - n: Actual number of objects enqueued.*/
static __rte_always_inline unsigned
rte_ring_enqueue_burst(struct rte_ring *r, void * const *obj_table,unsigned int n, unsigned int *free_space)
{return __rte_ring_do_enqueue(r, obj_table, n, RTE_RING_QUEUE_VARIABLE,r->prod.single, free_space);
}/*** Dequeue several objects from a ring (multi-consumers safe). When the request* objects are more than the available objects, only dequeue the actual number* of objects** This function uses a "compare and set" instruction to move the* consumer index atomically.** @param r*   A pointer to the ring structure.* @param obj_table*   A pointer to a table of void * pointers (objects) that will be filled.* @param n*   The number of objects to dequeue from the ring to the obj_table.* @param available*   If non-NULL, returns the number of remaining ring entries after the*   dequeue has finished.* @return*   - n: Actual number of objects dequeued, 0 if ring is empty*/
static __rte_always_inline unsigned
rte_ring_mc_dequeue_burst(struct rte_ring *r, void **obj_table,unsigned int n, unsigned int *available)
{return __rte_ring_do_dequeue(r, obj_table, n,RTE_RING_QUEUE_VARIABLE, __IS_MC, available);
}/*** Dequeue several objects from a ring (NOT multi-consumers safe).When the* request objects are more than the available objects, only dequeue the* actual number of objects** @param r*   A pointer to the ring structure.* @param obj_table*   A pointer to a table of void * pointers (objects) that will be filled.* @param n*   The number of objects to dequeue from the ring to the obj_table.* @param available*   If non-NULL, returns the number of remaining ring entries after the*   dequeue has finished.* @return*   - n: Actual number of objects dequeued, 0 if ring is empty*/
static __rte_always_inline unsigned
rte_ring_sc_dequeue_burst(struct rte_ring *r, void **obj_table,unsigned int n, unsigned int *available)
{return __rte_ring_do_dequeue(r, obj_table, n,RTE_RING_QUEUE_VARIABLE, __IS_SC, available);
}/*** Dequeue multiple objects from a ring up to a maximum number.** This function calls the multi-consumers or the single-consumer* version, depending on the default behaviour that was specified at* ring creation time (see flags).** @param r*   A pointer to the ring structure.* @param obj_table*   A pointer to a table of void * pointers (objects) that will be filled.* @param n*   The number of objects to dequeue from the ring to the obj_table.* @param available*   If non-NULL, returns the number of remaining ring entries after the*   dequeue has finished.* @return*   - Number of objects dequeued*/
static __rte_always_inline unsigned
rte_ring_dequeue_burst(struct rte_ring *r, void **obj_table,unsigned int n, unsigned int *available)
{return __rte_ring_do_dequeue(r, obj_table, n,RTE_RING_QUEUE_VARIABLE,r->cons.single, available);
}#ifdef __cplusplus
}
#endif#endif /* _RTE_RING_H_ */

rte_ring.c

/*-*   BSD LICENSE**   Copyright(c) 2010-2015 Intel Corporation. All rights reserved.*   All rights reserved.**   Redistribution and use in source and binary forms, with or without*   modification, are permitted provided that the following conditions*   are met:**     * Redistributions of source code must retain the above copyright*       notice, this list of conditions and the following disclaimer.*     * Redistributions in binary form must reproduce the above copyright*       notice, this list of conditions and the following disclaimer in*       the documentation and/or other materials provided with the*       distribution.*     * Neither the name of Intel Corporation nor the names of its*       contributors may be used to endorse or promote products derived*       from this software without specific prior written permission.**   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS*   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT*   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR*   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT*   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,*   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT*   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,*   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY*   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT*   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE*   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.*//** Derived from FreeBSD's bufring.c***************************************************************************** Copyright (c) 2007,2008 Kip Macy kmacy@freebsd.org* All rights reserved.** Redistribution and use in source and binary forms, with or without* modification, are permitted provided that the following conditions are met:** 1. Redistributions of source code must retain the above copyright notice,*    this list of conditions and the following disclaimer.** 2. The name of Kip Macy nor the names of other*    contributors may be used to endorse or promote products derived from*    this software without specific prior written permission.** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE* POSSIBILITY OF SUCH DAMAGE.****************************************************************************/#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <stdint.h>
#include <inttypes.h>
#include <errno.h>
#include <sys/queue.h>
#include "rte_ring.h"/* true if x is a power of 2 */
#define POWEROF2(x) ((((x)-1) & (x)) == 0)/* return the size of memory occupied by a ring */
ssize_t
rte_ring_get_memsize(unsigned count)
{ssize_t sz;/* count must be a power of 2 */if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK )) {return -EINVAL;}sz = sizeof(struct rte_ring) + count * sizeof(void *);return sz;
}int
rte_ring_init(struct rte_ring *r, const char *name, unsigned count,unsigned flags)
{int ret;/* init the ring structure */memset(r, 0, sizeof(*r));ret = snprintf(r->name, sizeof(r->name), "%s", name);if (ret < 0 || ret >= (int)sizeof(r->name))return -ENAMETOOLONG;r->flags = flags;r->prod.single = (flags & RING_F_SP_ENQ) ? __IS_SP : __IS_MP;r->cons.single = (flags & RING_F_SC_DEQ) ? __IS_SC : __IS_MC;if (flags & RING_F_EXACT_SZ) {r->size = rte_align32pow2(count + 1);r->mask = r->size - 1;r->capacity = count;} else {if ((!POWEROF2(count)) || (count > RTE_RING_SZ_MASK)) {return -EINVAL;}r->size = count;r->mask = count - 1;r->capacity = r->mask;}r->prod.head = r->cons.head = 0;r->prod.tail = r->cons.tail = 0;return 0;
}
#define valloc malloc
#define vfree free
/* create the ring */
struct rte_ring *
rte_ring_create(const char *name, unsigned count,unsigned flags)
{char mz_name[RTE_NAMESIZE];struct rte_ring *r;struct rte_tailq_entry *te;const struct rte_memzone *mz;ssize_t ring_size;int mz_flags = 0;const unsigned int requested_count = count;int ret;/* for an exact size ring, round up from count to a power of two */if (flags & RING_F_EXACT_SZ)count = rte_align32pow2(count + 1);ring_size = rte_ring_get_memsize(count);if (ring_size < 0) {return NULL;}ret = snprintf(mz_name, sizeof(mz_name), "%s%s",RTE_RING_MZ_PREFIX, name);if (ret < 0 || ret >= (int)sizeof(mz_name)) {return NULL;}r = (struct  rte_ring *)valloc(ring_size);rte_ring_init(r, name, requested_count, flags);return r;
}/* free the ring */
void
rte_ring_free(struct rte_ring *r)
{if (r == NULL)return;vfree(r);
}/* dump the status of the ring on the console */
void
rte_ring_dump(FILE *f, const struct rte_ring *r)
{fprintf(f, "ring <%s>@%p\n", r->name, r);fprintf(f, "  flags=%x\n", r->flags);fprintf(f, "  size=%"PRIu32"\n", r->size);fprintf(f, "  capacity=%"PRIu32"\n", r->capacity);fprintf(f, "  ct=%"PRIu32"\n", r->cons.tail);fprintf(f, "  ch=%"PRIu32"\n", r->cons.head);fprintf(f, "  pt=%"PRIu32"\n", r->prod.tail);fprintf(f, "  ph=%"PRIu32"\n", r->prod.head);fprintf(f, "  used=%u\n", rte_ring_count(r));fprintf(f, "  avail=%u\n", rte_ring_free_count(r));
}

main.c

#include <assert.h>
#include <pthread.h>
#include <signal.h>#include "rte_ring.h"struct data_struct {int msg_type;int msg_code;int msg_len;char data[0];
};int nr_of_queue_node = 4096;struct rte_ring *ring = NULL;void sig_handler(int signum)
{printf("Catch Ctrl+c\n");switch(signum) {case SIGINT:case SIGKILL:rte_ring_free(ring);default:;}
}void *enqueue_ring(void *arg)
{struct data_struct *data = NULL;while(1) {if(rte_ring_full(ring)) {
//            printf("Full.\n");continue;}data = malloc(512);assert(rte_ring_enqueue(ring, data) == 0);}
}void *dequeue_ring(void *arg)
{struct data_struct *data = NULL;while(1) {if(rte_ring_empty(ring)) {
//            printf("Empty.\n");continue;}assert(rte_ring_dequeue(ring, (void**)&data) == 0);free(data);}
}int main(int argc,char *argv[])
{int i;pthread_t penqueue1;pthread_t pdequeue1;ring = rte_ring_create("test",nr_of_queue_node, 0);pthread_create(&penqueue1, NULL, enqueue_ring, NULL);pthread_create(&pdequeue1, NULL, dequeue_ring, NULL);while(1) {sleep(1);}}

makefile

CC=gccINC+= -I.
LIB+= -pthreadCFLAGS+= -gTARGET= main
ALL:$(TARGET)OBJ= rte_ring.o main.o $(TARGET):$(OBJ)  $(CC) $(CFLAGS) -o $@ $^ $(LIB)%.o: %.c$(CC) $(CFLAGS) $(INC) -c -o $@ $<clean:rm -f *.orm -f $(TARGET) install:

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