FD.io VPP  v18.07-rc0-415-g6c78436
Vector Packet Processing
queue.c
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1 /*
2  *------------------------------------------------------------------
3  * svm_queue.c - unidirectional shared-memory queues
4  *
5  * Copyright (c) 2009 Cisco and/or its affiliates.
6  * Licensed under the Apache License, Version 2.0 (the "License");
7  * you may not use this file except in compliance with the License.
8  * You may obtain a copy of the License at:
9  *
10  * http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing, software
13  * distributed under the License is distributed on an "AS IS" BASIS,
14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing permissions and
16  * limitations under the License.
17  *------------------------------------------------------------------
18  */
19 
20 
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <pthread.h>
25 #include <vppinfra/mem.h>
26 #include <vppinfra/format.h>
27 #include <vppinfra/cache.h>
28 #include <svm/queue.h>
29 #include <vppinfra/time.h>
30 #include <signal.h>
31 
32 /*
33  * svm_queue_init
34  *
35  * nels = number of elements on the queue
36  * elsize = element size, presumably 4 and cacheline-size will
37  * be popular choices.
38  * pid = consumer pid
39  *
40  * The idea is to call this function in the queue consumer,
41  * and e-mail the queue pointer to the producer(s).
42  *
43  * The vpp process / main thread allocates one of these
44  * at startup; its main input queue. The vpp main input queue
45  * has a pointer to it in the shared memory segment header.
46  *
47  * You probably want to be on an svm data heap before calling this
48  * function.
49  */
51 svm_queue_init (int nels,
52  int elsize, int consumer_pid, int signal_when_queue_non_empty)
53 {
54  svm_queue_t *q;
55  pthread_mutexattr_t attr;
56  pthread_condattr_t cattr;
57 
59  + nels * elsize, CLIB_CACHE_LINE_BYTES);
60  memset (q, 0, sizeof (*q));
61 
62  q->elsize = elsize;
63  q->maxsize = nels;
64  q->consumer_pid = consumer_pid;
65  q->signal_when_queue_non_empty = signal_when_queue_non_empty;
66 
67  memset (&attr, 0, sizeof (attr));
68  memset (&cattr, 0, sizeof (cattr));
69 
70  if (pthread_mutexattr_init (&attr))
71  clib_unix_warning ("mutexattr_init");
72  if (pthread_mutexattr_setpshared (&attr, PTHREAD_PROCESS_SHARED))
73  clib_unix_warning ("pthread_mutexattr_setpshared");
74  if (pthread_mutex_init (&q->mutex, &attr))
75  clib_unix_warning ("mutex_init");
76  if (pthread_mutexattr_destroy (&attr))
77  clib_unix_warning ("mutexattr_destroy");
78  if (pthread_condattr_init (&cattr))
79  clib_unix_warning ("condattr_init");
80  /* prints funny-looking messages in the Linux target */
81  if (pthread_condattr_setpshared (&cattr, PTHREAD_PROCESS_SHARED))
82  clib_unix_warning ("condattr_setpshared");
83  if (pthread_cond_init (&q->condvar, &cattr))
84  clib_unix_warning ("cond_init1");
85  if (pthread_condattr_destroy (&cattr))
86  clib_unix_warning ("cond_init2");
87 
88  return (q);
89 }
90 
91 /*
92  * svm_queue_free
93  */
94 void
96 {
97  (void) pthread_mutex_destroy (&q->mutex);
98  (void) pthread_cond_destroy (&q->condvar);
99  clib_mem_free (q);
100 }
101 
102 void
104 {
105  pthread_mutex_lock (&q->mutex);
106 }
107 
108 void
110 {
111  pthread_mutex_unlock (&q->mutex);
112 }
113 
114 int
116 {
117  return q->cursize == q->maxsize;
118 }
119 
120 /*
121  * svm_queue_add_nolock
122  */
123 int
125 {
126  i8 *tailp;
127  int need_broadcast = 0;
128 
129  if (PREDICT_FALSE (q->cursize == q->maxsize))
130  {
131  while (q->cursize == q->maxsize)
132  {
133  (void) pthread_cond_wait (&q->condvar, &q->mutex);
134  }
135  }
136 
137  tailp = (i8 *) (&q->data[0] + q->elsize * q->tail);
138  clib_memcpy (tailp, elem, q->elsize);
139 
140  q->tail++;
141  q->cursize++;
142 
143  need_broadcast = (q->cursize == 1);
144 
145  if (q->tail == q->maxsize)
146  q->tail = 0;
147 
148  if (need_broadcast)
149  {
150  (void) pthread_cond_broadcast (&q->condvar);
151  if (q->signal_when_queue_non_empty)
152  kill (q->consumer_pid, q->signal_when_queue_non_empty);
153  }
154  return 0;
155 }
156 
157 int
159 {
160  i8 *tailp;
161 
162  if (PREDICT_FALSE (q->cursize == q->maxsize))
163  {
164  while (q->cursize == q->maxsize)
165  ;
166  }
167 
168  tailp = (i8 *) (&q->data[0] + q->elsize * q->tail);
169  clib_memcpy (tailp, elem, q->elsize);
170 
171  q->tail++;
172  q->cursize++;
173 
174  if (q->tail == q->maxsize)
175  q->tail = 0;
176  return 0;
177 }
178 
179 
180 /*
181  * svm_queue_add
182  */
183 int
184 svm_queue_add (svm_queue_t * q, u8 * elem, int nowait)
185 {
186  i8 *tailp;
187  int need_broadcast = 0;
188 
189  if (nowait)
190  {
191  /* zero on success */
192  if (pthread_mutex_trylock (&q->mutex))
193  {
194  return (-1);
195  }
196  }
197  else
198  pthread_mutex_lock (&q->mutex);
199 
200  if (PREDICT_FALSE (q->cursize == q->maxsize))
201  {
202  if (nowait)
203  {
204  pthread_mutex_unlock (&q->mutex);
205  return (-2);
206  }
207  while (q->cursize == q->maxsize)
208  {
209  (void) pthread_cond_wait (&q->condvar, &q->mutex);
210  }
211  }
212 
213  tailp = (i8 *) (&q->data[0] + q->elsize * q->tail);
214  clib_memcpy (tailp, elem, q->elsize);
215 
216  q->tail++;
217  q->cursize++;
218 
219  need_broadcast = (q->cursize == 1);
220 
221  if (q->tail == q->maxsize)
222  q->tail = 0;
223 
224  if (need_broadcast)
225  {
226  (void) pthread_cond_broadcast (&q->condvar);
227  if (q->signal_when_queue_non_empty)
228  kill (q->consumer_pid, q->signal_when_queue_non_empty);
229  }
230  pthread_mutex_unlock (&q->mutex);
231 
232  return 0;
233 }
234 
235 /*
236  * svm_queue_add2
237  */
238 int
239 svm_queue_add2 (svm_queue_t * q, u8 * elem, u8 * elem2, int nowait)
240 {
241  i8 *tailp;
242  int need_broadcast = 0;
243 
244  if (nowait)
245  {
246  /* zero on success */
247  if (pthread_mutex_trylock (&q->mutex))
248  {
249  return (-1);
250  }
251  }
252  else
253  pthread_mutex_lock (&q->mutex);
254 
255  if (PREDICT_FALSE (q->cursize + 1 == q->maxsize))
256  {
257  if (nowait)
258  {
259  pthread_mutex_unlock (&q->mutex);
260  return (-2);
261  }
262  while (q->cursize + 1 == q->maxsize)
263  {
264  (void) pthread_cond_wait (&q->condvar, &q->mutex);
265  }
266  }
267 
268  tailp = (i8 *) (&q->data[0] + q->elsize * q->tail);
269  clib_memcpy (tailp, elem, q->elsize);
270 
271  q->tail++;
272  q->cursize++;
273 
274  if (q->tail == q->maxsize)
275  q->tail = 0;
276 
277  need_broadcast = (q->cursize == 1);
278 
279  tailp = (i8 *) (&q->data[0] + q->elsize * q->tail);
280  clib_memcpy (tailp, elem2, q->elsize);
281 
282  q->tail++;
283  q->cursize++;
284 
285  if (q->tail == q->maxsize)
286  q->tail = 0;
287 
288  if (need_broadcast)
289  {
290  (void) pthread_cond_broadcast (&q->condvar);
291  if (q->signal_when_queue_non_empty)
292  kill (q->consumer_pid, q->signal_when_queue_non_empty);
293  }
294  pthread_mutex_unlock (&q->mutex);
295 
296  return 0;
297 }
298 
299 /*
300  * svm_queue_sub
301  */
302 int
304  u32 time)
305 {
306  i8 *headp;
307  int need_broadcast = 0;
308  int rc = 0;
309 
310  if (cond == SVM_Q_NOWAIT)
311  {
312  /* zero on success */
313  if (pthread_mutex_trylock (&q->mutex))
314  {
315  return (-1);
316  }
317  }
318  else
319  pthread_mutex_lock (&q->mutex);
320 
321  if (PREDICT_FALSE (q->cursize == 0))
322  {
323  if (cond == SVM_Q_NOWAIT)
324  {
325  pthread_mutex_unlock (&q->mutex);
326  return (-2);
327  }
328  else if (cond == SVM_Q_TIMEDWAIT)
329  {
330  struct timespec ts;
331  ts.tv_sec = unix_time_now () + time;
332  ts.tv_nsec = 0;
333  while (q->cursize == 0 && rc == 0)
334  {
335  rc = pthread_cond_timedwait (&q->condvar, &q->mutex, &ts);
336  }
337  if (rc == ETIMEDOUT)
338  {
339  pthread_mutex_unlock (&q->mutex);
340  return ETIMEDOUT;
341  }
342  }
343  else
344  {
345  while (q->cursize == 0)
346  {
347  (void) pthread_cond_wait (&q->condvar, &q->mutex);
348  }
349  }
350  }
351 
352  headp = (i8 *) (&q->data[0] + q->elsize * q->head);
353  clib_memcpy (elem, headp, q->elsize);
354 
355  q->head++;
356  /* $$$$ JFC shouldn't this be == 0? */
357  if (q->cursize == q->maxsize)
358  need_broadcast = 1;
359 
360  q->cursize--;
361 
362  if (q->head == q->maxsize)
363  q->head = 0;
364 
365  if (need_broadcast)
366  (void) pthread_cond_broadcast (&q->condvar);
367 
368  pthread_mutex_unlock (&q->mutex);
369 
370  return 0;
371 }
372 
373 int
375 {
376  int need_broadcast;
377  i8 *headp;
378 
379  pthread_mutex_lock (&q->mutex);
380  if (q->cursize == 0)
381  {
382  pthread_mutex_unlock (&q->mutex);
383  return -1;
384  }
385 
386  headp = (i8 *) (&q->data[0] + q->elsize * q->head);
387  clib_memcpy (elem, headp, q->elsize);
388 
389  q->head++;
390  need_broadcast = (q->cursize == q->maxsize / 2);
391  q->cursize--;
392 
393  if (PREDICT_FALSE (q->head == q->maxsize))
394  q->head = 0;
395  pthread_mutex_unlock (&q->mutex);
396 
397  if (need_broadcast)
398  (void) pthread_cond_broadcast (&q->condvar);
399 
400  return 0;
401 }
402 
403 int
405 {
406  i8 *headp;
407 
408  if (PREDICT_FALSE (q->cursize == 0))
409  {
410  while (q->cursize == 0)
411  ;
412  }
413 
414  headp = (i8 *) (&q->data[0] + q->elsize * q->head);
415  clib_memcpy (elem, headp, q->elsize);
416 
417  q->head++;
418  q->cursize--;
419 
420  if (q->head == q->maxsize)
421  q->head = 0;
422  return 0;
423 }
424 
425 /*
426  * fd.io coding-style-patch-verification: ON
427  *
428  * Local Variables:
429  * eval: (c-set-style "gnu")
430  * End:
431  */
int svm_queue_is_full(svm_queue_t *q)
Definition: queue.c:115
int svm_queue_add(svm_queue_t *q, u8 *elem, int nowait)
Definition: queue.c:184
int svm_queue_sub2(svm_queue_t *q, u8 *elem)
Definition: queue.c:374
int svm_queue_add_raw(svm_queue_t *q, u8 *elem)
Definition: queue.c:158
unsigned char u8
Definition: types.h:56
void svm_queue_unlock(svm_queue_t *q)
Definition: queue.c:109
svm_queue_t * svm_queue_init(int nels, int elsize, int consumer_pid, int signal_when_queue_non_empty)
Definition: queue.c:51
blocking call, return on signal or time-out
Definition: queue.h:54
int svm_queue_sub(svm_queue_t *q, u8 *elem, svm_q_conditional_wait_t cond, u32 time)
Definition: queue.c:303
static f64 unix_time_now(void)
Definition: time.h:228
unsigned int u32
Definition: types.h:88
int svm_queue_add2(svm_queue_t *q, u8 *elem, u8 *elem2, int nowait)
Definition: queue.c:239
void svm_queue_lock(svm_queue_t *q)
Definition: queue.c:103
#define PREDICT_FALSE(x)
Definition: clib.h:105
signed char i8
Definition: types.h:45
svm_q_conditional_wait_t
Definition: queue.h:39
#define clib_memcpy(a, b, c)
Definition: string.h:75
void svm_queue_free(svm_queue_t *q)
Definition: queue.c:95
static void clib_mem_free(void *p)
Definition: mem.h:179
int svm_queue_sub_raw(svm_queue_t *q, u8 *elem)
Definition: queue.c:404
#define clib_unix_warning(format, args...)
Definition: error.h:68
int svm_queue_add_nolock(svm_queue_t *q, u8 *elem)
Definition: queue.c:124
struct _svm_queue svm_queue_t
static void * clib_mem_alloc_aligned(uword size, uword align)
Definition: mem.h:120
#define CLIB_CACHE_LINE_BYTES
Definition: cache.h:62
non-blocking call
Definition: queue.h:49