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 <vppinfra/lock.h>
26 #include <svm/queue.h>
28 typedef struct svm_msg_q_shr_queue_
30 pthread_mutex_t mutex; /* 8 bytes */
31 pthread_cond_t condvar; /* 8 bytes */
39 } svm_msg_q_shared_queue_t;
41 typedef struct svm_msg_q_queue_
43 svm_msg_q_shared_queue_t *shr; /**< pointer to shared queue */
44 int evtfd; /**< producer/consumer eventfd */
45 clib_spinlock_t lock; /**< private lock for multi-producer */
48 typedef struct svm_msg_q_ring_shared_
50 volatile u32 cursize; /**< current size of the ring */
51 u32 nitems; /**< max size of the ring */
52 volatile u32 head; /**< current head (for dequeue) */
53 volatile u32 tail; /**< current tail (for enqueue) */
54 u32 elsize; /**< size of an element */
55 u8 data[0]; /**< chunk of memory for msg data */
56 } svm_msg_q_ring_shared_t;
58 typedef struct svm_msg_q_ring_
60 u32 nitems; /**< max size of the ring */
61 u32 elsize; /**< size of an element */
62 svm_msg_q_ring_shared_t *shr; /**< ring in shared memory */
63 } __clib_packed svm_msg_q_ring_t;
65 typedef struct svm_msg_q_shared_
67 u32 n_rings; /**< number of rings after q */
68 u32 pad; /**< 8 byte alignment for q */
69 svm_msg_q_shared_queue_t q[0]; /**< queue for exchanging messages */
70 } __clib_packed svm_msg_q_shared_t;
72 typedef struct svm_msg_q_
74 svm_msg_q_queue_t q; /**< queue for exchanging messages */
75 svm_msg_q_ring_t *rings; /**< rings with message data*/
76 } __clib_packed svm_msg_q_t;
78 typedef struct svm_msg_q_ring_cfg_
83 } svm_msg_q_ring_cfg_t;
85 typedef struct svm_msg_q_cfg_
87 int consumer_pid; /**< pid of msg consumer */
88 u32 q_nitems; /**< msg queue size (not rings) */
89 u32 n_rings; /**< number of msg rings */
90 svm_msg_q_ring_cfg_t *ring_cfgs; /**< array of ring cfgs */
97 u32 ring_index; /**< ring index, could be u8 */
98 u32 elt_index; /**< index in ring */
103 #define SVM_MQ_INVALID_MSG { .as_u64 = ~0 }
105 typedef enum svm_msg_q_wait_type_
109 } svm_msg_q_wait_type_t;
112 * Allocate message queue
114 * Allocates a message queue on the heap. Based on the configuration options,
115 * apart from the message queue this also allocates (one or multiple)
116 * shared-memory rings for the messages.
118 * @param cfg configuration options: queue len, consumer pid,
120 * @return message queue
122 svm_msg_q_shared_t *svm_msg_q_alloc (svm_msg_q_cfg_t *cfg);
123 svm_msg_q_shared_t *svm_msg_q_init (void *base, svm_msg_q_cfg_t *cfg);
124 uword svm_msg_q_size_to_alloc (svm_msg_q_cfg_t *cfg);
126 void svm_msg_q_attach (svm_msg_q_t *mq, void *smq_base);
131 * @param mq message queue to be freed
133 void svm_msg_q_free (svm_msg_q_t * mq);
136 * Allocate message buffer
138 * Message is allocated on the first available ring capable of holding
139 * the requested number of bytes.
141 * @param mq message queue
142 * @param nbytes number of bytes needed for message
143 * @return message structure pointing to the ring and position
146 svm_msg_q_msg_t svm_msg_q_alloc_msg (svm_msg_q_t * mq, u32 nbytes);
149 * Allocate message buffer on ring
151 * Message is allocated, on requested ring. The caller MUST check that
152 * the ring is not full.
154 * @param mq message queue
155 * @param ring_index ring on which the allocation should occur
156 * @return message structure pointing to the ring and position
159 svm_msg_q_msg_t svm_msg_q_alloc_msg_w_ring (svm_msg_q_t * mq, u32 ring_index);
162 * Lock message queue and allocate message buffer on ring
164 * This should be used when multiple writers/readers are expected to
165 * compete for the rings/queue. Message should be enqueued by calling
166 * @ref svm_msg_q_add_w_lock and the caller MUST unlock the queue once
167 * the message in enqueued.
169 * @param mq message queue
170 * @param ring_index ring on which the allocation should occur
171 * @param noblock flag that indicates if request should block
172 * @param msg pointer to message to be filled in
173 * @return 0 on success, negative number otherwise
175 int svm_msg_q_lock_and_alloc_msg_w_ring (svm_msg_q_t * mq, u32 ring_index,
176 u8 noblock, svm_msg_q_msg_t * msg);
179 * Free message buffer
181 * Marks message buffer on ring as free.
183 * @param mq message queue
184 * @param msg message to be freed
186 void svm_msg_q_free_msg (svm_msg_q_t * mq, svm_msg_q_msg_t * msg);
189 * Producer enqueue one message to queue
191 * Prior to calling this, the producer should've obtained a message buffer
192 * from one of the rings by calling @ref svm_msg_q_alloc_msg.
194 * @param mq message queue
195 * @param msg message (pointer to ring position) to be enqueued
196 * @param nowait flag to indicate if request is blocking or not
197 * @return success status
199 int svm_msg_q_add (svm_msg_q_t * mq, svm_msg_q_msg_t * msg, int nowait);
202 * Producer enqueue one message to queue with mutex held
204 * Prior to calling this, the producer should've obtained a message buffer
205 * from one of the rings by calling @ref svm_msg_q_alloc_msg. It assumes
206 * the queue mutex is held.
208 * @param mq message queue
209 * @param msg message (pointer to ring position) to be enqueued
210 * @return success status
212 void svm_msg_q_add_and_unlock (svm_msg_q_t * mq, svm_msg_q_msg_t * msg);
215 * Consumer dequeue one message from queue
217 * This returns the message pointing to the data in the message rings.
218 * Should only be used in single consumer scenarios as no locks are grabbed.
219 * The consumer is expected to call @ref svm_msg_q_free_msg once it
220 * finishes processing/copies the message data.
222 * @param mq message queue
223 * @param msg pointer to structure where message is to be received
224 * @param cond flag that indicates if request should block or not
225 * @param time time to wait if condition it SVM_Q_TIMEDWAIT
226 * @return success status
228 int svm_msg_q_sub (svm_msg_q_t * mq, svm_msg_q_msg_t * msg,
229 svm_q_conditional_wait_t cond, u32 time);
232 * Consumer dequeue one message from queue
234 * Returns the message pointing to the data in the message rings. Should only
235 * be used in single consumer scenarios as no locks are grabbed. The consumer
236 * is expected to call @ref svm_msg_q_free_msg once it finishes
237 * processing/copies the message data.
239 * @param mq message queue
240 * @param msg pointer to structure where message is to be received
241 * @return success status
243 int svm_msg_q_sub_raw (svm_msg_q_t *mq, svm_msg_q_msg_t *elem);
246 * Consumer dequeue multiple messages from queue
248 * Returns the message pointing to the data in the message rings. Should only
249 * be used in single consumer scenarios as no locks are grabbed. The consumer
250 * is expected to call @ref svm_msg_q_free_msg once it finishes
251 * processing/copies the message data.
253 * @param mq message queue
254 * @param msg_buf pointer to array of messages to received
255 * @param n_msgs lengt of msg_buf array
256 * @return number of messages dequeued
258 int svm_msg_q_sub_raw_batch (svm_msg_q_t *mq, svm_msg_q_msg_t *msg_buf,
262 * Get data for message in queue
264 * @param mq message queue
265 * @param msg message for which the data is requested
266 * @return pointer to data
268 void *svm_msg_q_msg_data (svm_msg_q_t * mq, svm_msg_q_msg_t * msg);
271 * Get message queue ring
273 * @param mq message queue
274 * @param ring_index index of ring
275 * @return pointer to ring
277 svm_msg_q_ring_t *svm_msg_q_ring (svm_msg_q_t * mq, u32 ring_index);
280 * Set event fd for queue
282 * If set, queue will exclusively use eventfds for signaling. Moreover,
283 * afterwards, the queue should only be used in non-blocking mode. Waiting
284 * for events should be done externally using something like epoll.
286 * @param mq message queue
287 * @param fd consumer eventfd
289 void svm_msg_q_set_eventfd (svm_msg_q_t *mq, int fd);
292 * Allocate event fd for queue
294 int svm_msg_q_alloc_eventfd (svm_msg_q_t *mq);
297 * Format message queue, shows msg count for each ring
299 u8 *format_svm_msg_q (u8 *s, va_list *args);
302 * Check length of message queue
305 svm_msg_q_size (svm_msg_q_t *mq)
307 return clib_atomic_load_relax_n (&mq->q.shr->cursize);
311 * Check if message queue is full
314 svm_msg_q_is_full (svm_msg_q_t * mq)
316 return (svm_msg_q_size (mq) == mq->q.shr->maxsize);
320 svm_msg_q_ring_is_full (svm_msg_q_t * mq, u32 ring_index)
322 svm_msg_q_ring_t *ring = vec_elt_at_index (mq->rings, ring_index);
323 return (clib_atomic_load_relax_n (&ring->shr->cursize) >= ring->nitems);
327 * Check if message queue is empty
330 svm_msg_q_is_empty (svm_msg_q_t * mq)
332 return (svm_msg_q_size (mq) == 0);
336 * Check if message is invalid
339 svm_msg_q_msg_is_invalid (svm_msg_q_msg_t * msg)
341 return (msg->as_u64 == (u64) ~ 0);
345 * Try locking message queue
348 svm_msg_q_try_lock (svm_msg_q_t * mq)
350 if (mq->q.evtfd == -1)
352 int rv = pthread_mutex_trylock (&mq->q.shr->mutex);
353 if (PREDICT_FALSE (rv == EOWNERDEAD))
354 rv = pthread_mutex_consistent (&mq->q.shr->mutex);
359 return !clib_spinlock_trylock (&mq->q.lock);
364 * Lock, or block trying, the message queue
367 svm_msg_q_lock (svm_msg_q_t * mq)
369 if (mq->q.evtfd == -1)
371 int rv = pthread_mutex_lock (&mq->q.shr->mutex);
372 if (PREDICT_FALSE (rv == EOWNERDEAD))
373 rv = pthread_mutex_consistent (&mq->q.shr->mutex);
378 clib_spinlock_lock (&mq->q.lock);
384 * Unlock message queue
387 svm_msg_q_unlock (svm_msg_q_t * mq)
389 if (mq->q.evtfd == -1)
391 pthread_mutex_unlock (&mq->q.shr->mutex);
395 clib_spinlock_unlock (&mq->q.lock);
400 * Wait for message queue event
402 * Must be called with mutex held. The queue only works non-blocking
403 * with eventfds, so handle blocking calls as an exception here.
405 int svm_msg_q_wait (svm_msg_q_t *mq, svm_msg_q_wait_type_t type);
408 * Timed wait for message queue event
410 * Must be called with mutex held.
412 * @param mq message queue
413 * @param timeout time in seconds
415 int svm_msg_q_timedwait (svm_msg_q_t *mq, double timeout);
418 svm_msg_q_get_eventfd (svm_msg_q_t *mq)
423 #endif /* SRC_SVM_MESSAGE_QUEUE_H_ */
426 * fd.io coding-style-patch-verification: ON
429 * eval: (c-set-style "gnu")