-/*-
- * 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
- *
- **************************************************************************
+/* SPDX-License-Identifier: BSD-3-Clause
*
+ * Copyright (c) 2010-2017 Intel Corporation
* 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.
- *
- ***************************************************************************/
+ * Derived from FreeBSD's bufring.h
+ * Used as BSD-3 Licensed with permission from Kip Macy.
+ */
#ifndef _RTE_RING_H_
#define _RTE_RING_H_
* - 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.
+ * Note: the ring implementation is not preemptible. Refer to Programmer's
+ * guide/Environment Abstraction Layer/Multiple pthread/Known Issues/rte_ring
+ * for more information.
*
*/
#include <sys/queue.h>
#include <errno.h>
#include <rte_common.h>
+#include <rte_config.h>
#include <rte_memory.h>
#include <rte_lcore.h>
#include <rte_atomic.h>
#include <rte_branch_prediction.h>
#include <rte_memzone.h>
+#include <rte_pause.h>
#define RTE_TAILQ_RING_NAME "RTE_RING"
};
#define RTE_RING_MZ_PREFIX "RG_"
-/**< The maximum length of a ring name. */
+/** The maximum length of a ring name. */
#define RTE_RING_NAMESIZE (RTE_MEMZONE_NAMESIZE - \
sizeof(RTE_RING_MZ_PREFIX) + 1)
-struct rte_memzone; /* forward declaration, so as not to require memzone.h */
-
-#if RTE_CACHE_LINE_SIZE < 128
-#define PROD_ALIGN (RTE_CACHE_LINE_SIZE * 2)
-#define CONS_ALIGN (RTE_CACHE_LINE_SIZE * 2)
-#else
-#define PROD_ALIGN RTE_CACHE_LINE_SIZE
-#define CONS_ALIGN RTE_CACHE_LINE_SIZE
-#endif
-
/* structure to hold a pair of head/tail values and other metadata */
struct rte_ring_headtail {
volatile uint32_t head; /**< Prod/consumer head. */
/**< 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 */
+
+ char pad0 __rte_cache_aligned; /**< empty cache line */
/** Ring producer status. */
- struct rte_ring_headtail prod __rte_aligned(PROD_ALIGN);
+ struct rte_ring_headtail prod __rte_cache_aligned;
+ char pad1 __rte_cache_aligned; /**< empty cache line */
/** Ring consumer status. */
- struct rte_ring_headtail cons __rte_aligned(CONS_ALIGN);
+ struct rte_ring_headtail cons __rte_cache_aligned;
+ char pad2 __rte_cache_aligned; /**< empty cache line */
};
#define RING_F_SP_ENQ 0x0001 /**< The default enqueue is "single-producer". */
#define RING_F_SC_DEQ 0x0002 /**< The default dequeue is "single-consumer". */
-#define RTE_RING_SZ_MASK (unsigned)(0x0fffffff) /**< Ring size mask */
+/**
+ * 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 (0x7fffffffU) /**< Ring size mask */
/* @internal defines for passing to the enqueue dequeue worker functions */
#define __IS_SP 1
*/
struct rte_ring *rte_ring_create(const char *name, unsigned count,
int socket_id, unsigned flags);
+
/**
* De-allocate all memory used by the ring.
*
} \
} 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 (unlikely(ht->tail != old_val))
- rte_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 mask = r->mask;
- 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 size(ring)-1. */
- *free_entries = (mask + cons_tail - *old_head);
-
- /* check that we have enough room in ring */
- if (unlikely(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;
- else
- success = rte_atomic32_cmpset(&r->prod.head,
- *old_head, *new_head);
- } while (unlikely(success == 0));
- return n;
-}
+/* Between load and load. there might be cpu reorder in weak model
+ * (powerpc/arm).
+ * There are 2 choices for the users
+ * 1.use rmb() memory barrier
+ * 2.use one-direction load_acquire/store_release barrier,defined by
+ * CONFIG_RTE_USE_C11_MEM_MODEL=y
+ * It depends on performance test results.
+ * By default, move common functions to rte_ring_generic.h
+ */
+#ifdef RTE_USE_C11_MEM_MODEL
+#include "rte_ring_c11_mem.h"
+#else
+#include "rte_ring_generic.h"
+#endif
/**
* @internal Enqueue several objects on the ring
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)
+ unsigned int is_sp, unsigned int *free_space)
{
uint32_t prod_head, prod_next;
uint32_t free_entries;
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);
+ update_tail(&r->prod, prod_head, prod_next, is_sp, 1);
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 (unlikely(n == 0))
- return 0;
-
- *new_head = *old_head + n;
- if (is_sc)
- r->cons.head = *new_head, success = 1;
- else
- success = rte_atomic32_cmpset(&r->cons.head, *old_head,
- *new_head);
- } while (unlikely(success == 0));
- return n;
-}
-
/**
* @internal Dequeue several objects from the ring
*
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)
+ unsigned 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,
+ n = __rte_ring_move_cons_head(r, (int)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);
+ update_tail(&r->cons, cons_head, cons_next, is_sc, 0);
end:
if (available != NULL)
}
/**
- * Test if a ring is full.
+ * Flush a ring.
+ *
+ * This function flush all the elements in a ring
+ *
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * @warning
+ * Make sure the ring is not in use while calling this function.
+ *
+ * @param r
+ * A pointer to the ring structure.
+ */
+__rte_experimental
+void
+rte_ring_reset(struct rte_ring *r);
+
+/**
+ * Return the number of entries in a ring.
*
* @param r
* A pointer to the ring structure.
* @return
- * - 1: The ring is full.
- * - 0: The ring is not full.
+ * The number of entries in the ring.
*/
-static inline int
-rte_ring_full(const struct rte_ring *r)
+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;
- return ((cons_tail - prod_tail - 1) & r->mask) == 0;
+ uint32_t count = (prod_tail - cons_tail) & r->mask;
+ return (count > r->capacity) ? r->capacity : count;
}
/**
- * Test if a ring is empty.
+ * Return the number of free entries in a ring.
*
* @param r
* A pointer to the ring structure.
* @return
- * - 1: The ring is empty.
- * - 0: The ring is not empty.
+ * The number of free entries in the ring.
*/
-static inline int
-rte_ring_empty(const struct rte_ring *r)
+static inline unsigned
+rte_ring_free_count(const struct rte_ring *r)
{
- uint32_t prod_tail = r->prod.tail;
- uint32_t cons_tail = r->cons.tail;
- return !!(cons_tail == prod_tail);
+ return r->capacity - rte_ring_count(r);
}
/**
- * Return the number of entries in a ring.
+ * Test if a ring is full.
*
* @param r
* A pointer to the ring structure.
* @return
- * The number of entries in the ring.
+ * - 1: The ring is full.
+ * - 0: The ring is not full.
*/
-static inline unsigned
-rte_ring_count(const struct rte_ring *r)
+static inline int
+rte_ring_full(const struct rte_ring *r)
{
- uint32_t prod_tail = r->prod.tail;
- uint32_t cons_tail = r->cons.tail;
- return (prod_tail - cons_tail) & r->mask;
+ return rte_ring_free_count(r) == 0;
}
/**
- * Return the number of free entries in a ring.
+ * Test if a ring is empty.
*
* @param r
* A pointer to the ring structure.
* @return
- * The number of free entries in the ring.
+ * - 1: The ring is empty.
+ * - 0: The ring is not empty.
*/
-static inline unsigned
-rte_ring_free_count(const struct rte_ring *r)
+static inline int
+rte_ring_empty(const struct rte_ring *r)
{
- uint32_t prod_tail = r->prod.tail;
- uint32_t cons_tail = r->cons.tail;
- return (cons_tail - prod_tail - 1) & r->mask;
+ return rte_ring_count(r) == 0;
}
/**
* @param r
* A pointer to the ring structure.
* @return
- * The number of elements which can be stored in the ring.
+ * 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
*