2 * Copyright (c) 2018-2019 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 */
35 } __clib_packed svm_msg_q_ring_t;
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*/
41 } __clib_packed svm_msg_q_t;
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);
81 svm_msg_q_t *svm_msg_q_init (void *base, svm_msg_q_cfg_t *cfg);
82 uword svm_msg_q_size_to_alloc (svm_msg_q_cfg_t *cfg);
87 * @param mq message queue to be freed
89 void svm_msg_q_free (svm_msg_q_t * mq);
92 * Allocate message buffer
94 * Message is allocated on the first available ring capable of holding
95 * the requested number of bytes.
97 * @param mq message queue
98 * @param nbytes number of bytes needed for message
99 * @return message structure pointing to the ring and position
102 svm_msg_q_msg_t svm_msg_q_alloc_msg (svm_msg_q_t * mq, u32 nbytes);
105 * Allocate message buffer on ring
107 * Message is allocated, on requested ring. The caller MUST check that
108 * the ring is not full.
110 * @param mq message queue
111 * @param ring_index ring on which the allocation should occur
112 * @return message structure pointing to the ring and position
115 svm_msg_q_msg_t svm_msg_q_alloc_msg_w_ring (svm_msg_q_t * mq, u32 ring_index);
118 * Lock message queue and allocate message buffer on ring
120 * This should be used when multiple writers/readers are expected to
121 * compete for the rings/queue. Message should be enqueued by calling
122 * @ref svm_msg_q_add_w_lock and the caller MUST unlock the queue once
123 * the message in enqueued.
125 * @param mq message queue
126 * @param ring_index ring on which the allocation should occur
127 * @param noblock flag that indicates if request should block
128 * @param msg pointer to message to be filled in
129 * @return 0 on success, negative number otherwise
131 int svm_msg_q_lock_and_alloc_msg_w_ring (svm_msg_q_t * mq, u32 ring_index,
132 u8 noblock, svm_msg_q_msg_t * msg);
135 * Free message buffer
137 * Marks message buffer on ring as free.
139 * @param mq message queue
140 * @param msg message to be freed
142 void svm_msg_q_free_msg (svm_msg_q_t * mq, svm_msg_q_msg_t * msg);
145 * Producer enqueue one message to queue
147 * Prior to calling this, the producer should've obtained a message buffer
148 * from one of the rings by calling @ref svm_msg_q_alloc_msg.
150 * @param mq message queue
151 * @param msg message (pointer to ring position) to be enqueued
152 * @param nowait flag to indicate if request is blocking or not
153 * @return success status
155 int svm_msg_q_add (svm_msg_q_t * mq, svm_msg_q_msg_t * msg, int nowait);
158 * Producer enqueue one message to queue with mutex held
160 * Prior to calling this, the producer should've obtained a message buffer
161 * from one of the rings by calling @ref svm_msg_q_alloc_msg. It assumes
162 * the queue mutex is held.
164 * @param mq message queue
165 * @param msg message (pointer to ring position) to be enqueued
166 * @return success status
168 void svm_msg_q_add_and_unlock (svm_msg_q_t * mq, svm_msg_q_msg_t * msg);
171 * Consumer dequeue one message from queue
173 * This returns the message pointing to the data in the message rings.
174 * The consumer is expected to call @ref svm_msg_q_free_msg once it
175 * finishes processing/copies the message data.
177 * @param mq message queue
178 * @param msg pointer to structure where message is to be received
179 * @param cond flag that indicates if request should block or not
180 * @param time time to wait if condition it SVM_Q_TIMEDWAIT
181 * @return success status
183 int svm_msg_q_sub (svm_msg_q_t * mq, svm_msg_q_msg_t * msg,
184 svm_q_conditional_wait_t cond, u32 time);
187 * Consumer dequeue one message from queue with mutex held
189 * Returns the message pointing to the data in the message rings under the
190 * assumption that the message queue lock is already held. The consumer is
191 * expected to call @ref svm_msg_q_free_msg once it finishes
192 * processing/copies the message data.
194 * @param mq message queue
195 * @param msg pointer to structure where message is to be received
196 * @return success status
198 void svm_msg_q_sub_w_lock (svm_msg_q_t * mq, svm_msg_q_msg_t * msg);
201 * Get data for message in queue
203 * @param mq message queue
204 * @param msg message for which the data is requested
205 * @return pointer to data
207 void *svm_msg_q_msg_data (svm_msg_q_t * mq, svm_msg_q_msg_t * msg);
210 * Get message queue ring
212 * @param mq message queue
213 * @param ring_index index of ring
214 * @return pointer to ring
216 svm_msg_q_ring_t *svm_msg_q_ring (svm_msg_q_t * mq, u32 ring_index);
219 * Set event fd for queue consumer
221 * If set, queue will exclusively use eventfds for signaling. Moreover,
222 * afterwards, the queue should only be used in non-blocking mode. Waiting
223 * for events should be done externally using something like epoll.
225 * @param mq message queue
226 * @param fd consumer eventfd
228 void svm_msg_q_set_consumer_eventfd (svm_msg_q_t * mq, int fd);
231 * Set event fd for queue producer
233 * If set, queue will exclusively use eventfds for signaling. Moreover,
234 * afterwards, the queue should only be used in non-blocking mode. Waiting
235 * for events should be done externally using something like epoll.
237 * @param mq message queue
238 * @param fd producer eventfd
240 void svm_msg_q_set_producer_eventfd (svm_msg_q_t * mq, int fd);
243 * Allocate event fd for queue consumer
245 int svm_msg_q_alloc_consumer_eventfd (svm_msg_q_t * mq);
248 * Allocate event fd for queue consumer
250 int svm_msg_q_alloc_producer_eventfd (svm_msg_q_t * mq);
254 * Format message queue, shows msg count for each ring
256 u8 *format_svm_msg_q (u8 * s, va_list * args);
259 * Check if message queue is full
262 svm_msg_q_is_full (svm_msg_q_t * mq)
264 return (mq->q->cursize == mq->q->maxsize);
268 svm_msg_q_ring_is_full (svm_msg_q_t * mq, u32 ring_index)
270 ASSERT (ring_index < vec_len (mq->rings));
271 return (mq->rings[ring_index].cursize == mq->rings[ring_index].nitems);
275 * Check if message queue is empty
278 svm_msg_q_is_empty (svm_msg_q_t * mq)
280 return (mq->q->cursize == 0);
284 * Check length of message queue
287 svm_msg_q_size (svm_msg_q_t * mq)
289 return mq->q->cursize;
293 * Check if message is invalid
296 svm_msg_q_msg_is_invalid (svm_msg_q_msg_t * msg)
298 return (msg->as_u64 == (u64) ~ 0);
302 * Try locking message queue
305 svm_msg_q_try_lock (svm_msg_q_t * mq)
307 int rv = pthread_mutex_trylock (&mq->q->mutex);
308 if (PREDICT_FALSE (rv == EOWNERDEAD))
309 rv = pthread_mutex_consistent (&mq->q->mutex);
314 * Lock, or block trying, the message queue
317 svm_msg_q_lock (svm_msg_q_t * mq)
319 int rv = pthread_mutex_lock (&mq->q->mutex);
320 if (PREDICT_FALSE (rv == EOWNERDEAD))
321 rv = pthread_mutex_consistent (&mq->q->mutex);
326 * Unlock message queue
329 svm_msg_q_unlock (svm_msg_q_t * mq)
331 pthread_mutex_unlock (&mq->q->mutex);
335 * Wait for message queue event
337 * Must be called with mutex held. The queue only works non-blocking
338 * with eventfds, so handle blocking calls as an exception here.
341 svm_msg_q_wait (svm_msg_q_t * mq)
343 svm_queue_wait (mq->q);
347 * Timed wait for message queue event
349 * Must be called with mutex held.
351 * @param mq message queue
352 * @param timeout time in seconds
355 svm_msg_q_timedwait (svm_msg_q_t * mq, double timeout)
357 return svm_queue_timedwait (mq->q, timeout);
361 svm_msg_q_get_consumer_eventfd (svm_msg_q_t * mq)
363 return mq->q->consumer_evtfd;
367 svm_msg_q_get_producer_eventfd (svm_msg_q_t * mq)
369 return mq->q->producer_evtfd;
372 #endif /* SRC_SVM_MESSAGE_QUEUE_H_ */
375 * fd.io coding-style-patch-verification: ON
378 * eval: (c-set-style "gnu")