2 * Copyright (c) 2018 Cisco and/or its affiliates.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
17 * @brief Unidirectional shared-memory multi-ring message queue
20 #ifndef SRC_SVM_MESSAGE_QUEUE_H_
21 #define SRC_SVM_MESSAGE_QUEUE_H_
23 #include <vppinfra/clib.h>
24 #include <vppinfra/error.h>
25 #include <svm/queue.h>
27 typedef struct svm_msg_q_ring_
29 volatile u32 cursize; /**< current size of the ring */
30 u32 nitems; /**< max size of the ring */
31 volatile u32 head; /**< current head (for dequeue) */
32 volatile u32 tail; /**< current tail (for enqueue) */
33 u32 elsize; /**< size of an element */
34 u8 *data; /**< chunk of memory for msg data */
37 typedef struct svm_msg_q_
39 svm_queue_t *q; /**< queue for exchanging messages */
40 svm_msg_q_ring_t *rings; /**< rings with message data*/
43 typedef struct svm_msg_q_ring_cfg_
48 } svm_msg_q_ring_cfg_t;
50 typedef struct svm_msg_q_cfg_
52 int consumer_pid; /**< pid of msg consumer */
53 u32 q_nitems; /**< msg queue size (not rings) */
54 u32 n_rings; /**< number of msg rings */
55 svm_msg_q_ring_cfg_t *ring_cfgs; /**< array of ring cfgs */
62 u32 ring_index; /**< ring index, could be u8 */
63 u32 elt_index; /**< index in ring */
68 #define SVM_MQ_INVALID_MSG { .as_u64 = ~0 }
70 * Allocate message queue
72 * Allocates a message queue on the heap. Based on the configuration options,
73 * apart from the message queue this also allocates (one or multiple)
74 * shared-memory rings for the messages.
76 * @param cfg configuration options: queue len, consumer pid,
78 * @return message queue
80 svm_msg_q_t *svm_msg_q_alloc (svm_msg_q_cfg_t * cfg);
85 * @param mq message queue to be freed
87 void svm_msg_q_free (svm_msg_q_t * mq);
90 * Allocate message buffer
92 * Message is allocated on the first available ring capable of holding
93 * the requested number of bytes.
95 * @param mq message queue
96 * @param nbytes number of bytes needed for message
97 * @return message structure pointing to the ring and position
100 svm_msg_q_msg_t svm_msg_q_alloc_msg (svm_msg_q_t * mq, u32 nbytes);
103 * Allocate message buffer on ring
105 * Message is allocated, on requested ring. The caller MUST check that
106 * the ring is not full.
108 * @param mq message queue
109 * @param ring_index ring on which the allocation should occur
110 * @return message structure pointing to the ring and position
113 svm_msg_q_msg_t svm_msg_q_alloc_msg_w_ring (svm_msg_q_t * mq, u32 ring_index);
116 * Lock message queue and allocate message buffer on ring
118 * This should be used when multiple writers/readers are expected to
119 * compete for the rings/queue. Message should be enqueued by calling
120 * @ref svm_msg_q_add_w_lock and the caller MUST unlock the queue once
121 * the message in enqueued.
123 * @param mq message queue
124 * @param ring_index ring on which the allocation should occur
125 * @param noblock flag that indicates if request should block
126 * @param msg pointer to message to be filled in
127 * @return 0 on success, negative number otherwise
129 int svm_msg_q_lock_and_alloc_msg_w_ring (svm_msg_q_t * mq, u32 ring_index,
130 u8 noblock, svm_msg_q_msg_t * msg);
133 * Free message buffer
135 * Marks message buffer on ring as free.
137 * @param mq message queue
138 * @param msg message to be freed
140 void svm_msg_q_free_msg (svm_msg_q_t * mq, svm_msg_q_msg_t * msg);
143 * Producer enqueue one message to queue
145 * Prior to calling this, the producer should've obtained a message buffer
146 * from one of the rings by calling @ref svm_msg_q_alloc_msg.
148 * @param mq message queue
149 * @param msg message (pointer to ring position) to be enqueued
150 * @param nowait flag to indicate if request is blocking or not
151 * @return success status
153 int svm_msg_q_add (svm_msg_q_t * mq, svm_msg_q_msg_t * msg, int nowait);
156 * Producer enqueue one message to queue with mutex held
158 * Prior to calling this, the producer should've obtained a message buffer
159 * from one of the rings by calling @ref svm_msg_q_alloc_msg. It assumes
160 * the queue mutex is held.
162 * @param mq message queue
163 * @param msg message (pointer to ring position) to be enqueued
164 * @return success status
166 void svm_msg_q_add_and_unlock (svm_msg_q_t * mq, svm_msg_q_msg_t * msg);
169 * Consumer dequeue one message from queue
171 * This returns the message pointing to the data in the message rings.
172 * The consumer is expected to call @ref svm_msg_q_free_msg once it
173 * finishes processing/copies the message data.
175 * @param mq message queue
176 * @param msg pointer to structure where message is to be received
177 * @param cond flag that indicates if request should block or not
178 * @param time time to wait if condition it SVM_Q_TIMEDWAIT
179 * @return success status
181 int svm_msg_q_sub (svm_msg_q_t * mq, svm_msg_q_msg_t * msg,
182 svm_q_conditional_wait_t cond, u32 time);
185 * Consumer dequeue one message from queue with mutex held
187 * Returns the message pointing to the data in the message rings under the
188 * assumption that the message queue lock is already held. The consumer is
189 * expected to call @ref svm_msg_q_free_msg once it finishes
190 * processing/copies the message data.
192 * @param mq message queue
193 * @param msg pointer to structure where message is to be received
194 * @return success status
196 void svm_msg_q_sub_w_lock (svm_msg_q_t * mq, svm_msg_q_msg_t * msg);
199 * Get data for message in queue
201 * @param mq message queue
202 * @param msg message for which the data is requested
203 * @return pointer to data
205 void *svm_msg_q_msg_data (svm_msg_q_t * mq, svm_msg_q_msg_t * msg);
208 * Get message queue ring
210 * @param mq message queue
211 * @param ring_index index of ring
212 * @return pointer to ring
214 svm_msg_q_ring_t *svm_msg_q_ring (svm_msg_q_t * mq, u32 ring_index);
217 * Check if message queue is full
220 svm_msg_q_is_full (svm_msg_q_t * mq)
222 return (mq->q->cursize == mq->q->maxsize);
226 svm_msg_q_ring_is_full (svm_msg_q_t * mq, u32 ring_index)
228 ASSERT (ring_index < vec_len (mq->rings));
229 return (mq->rings[ring_index].cursize == mq->rings[ring_index].nitems);
233 * Check if message queue is empty
236 svm_msg_q_is_empty (svm_msg_q_t * mq)
238 return (mq->q->cursize == 0);
242 * Check length of message queue
245 svm_msg_q_size (svm_msg_q_t * mq)
247 return mq->q->cursize;
251 * Check if message is invalid
254 svm_msg_q_msg_is_invalid (svm_msg_q_msg_t * msg)
256 return (msg->as_u64 == (u64) ~ 0);
260 * Try locking message queue
263 svm_msg_q_try_lock (svm_msg_q_t * mq)
265 return pthread_mutex_trylock (&mq->q->mutex);
269 * Lock, or block trying, the message queue
272 svm_msg_q_lock (svm_msg_q_t * mq)
274 return pthread_mutex_lock (&mq->q->mutex);
278 svm_msg_q_wait (svm_msg_q_t * mq)
280 pthread_cond_wait (&mq->q->condvar, &mq->q->mutex);
284 * Unlock message queue
287 svm_msg_q_unlock (svm_msg_q_t * mq)
289 /* The other side of the connection is not polling */
290 if (mq->q->cursize < (mq->q->maxsize / 8))
291 (void) pthread_cond_broadcast (&mq->q->condvar);
292 pthread_mutex_unlock (&mq->q->mutex);
295 #endif /* SRC_SVM_MESSAGE_QUEUE_H_ */
298 * fd.io coding-style-patch-verification: ON
301 * eval: (c-set-style "gnu")