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0c1b0f77 JG |
1 | /* |
2 | * Copyright (C) 2019 - Jérémie Galarneau <jeremie.galarneau@efficios.com> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License, version 2 only, | |
6 | * as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
11 | * more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License along | |
14 | * with this program; if not, write to the Free Software Foundation, Inc., | |
15 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
16 | */ | |
17 | ||
18 | #include "sessiond-trace-chunks.h" | |
19 | #include <urcu.h> | |
20 | #include <urcu/rculfhash.h> | |
21 | #include <urcu/ref.h> | |
22 | #include <common/macros.h> | |
23 | #include <common/hashtable/hashtable.h> | |
24 | #include <common/hashtable/utils.h> | |
25 | #include <common/trace-chunk-registry.h> | |
26 | #include <common/defaults.h> | |
27 | #include <common/error.h> | |
28 | #include <common/string-utils/format.h> | |
29 | #include <stdio.h> | |
30 | #include <inttypes.h> | |
31 | ||
32 | /* | |
33 | * Lifetime of trace chunks within the relay daemon. | |
34 | * | |
35 | * Trace chunks are shared accross connections initiated from a given | |
36 | * session daemon. When a session is created by a consumer daemon, the | |
37 | * UUID of its associated session daemon is transmitted (in the case of | |
38 | * 2.11+ consumer daemons). | |
39 | * | |
40 | * The sessiond_trace_chunk_registry_new_session() and | |
41 | * sessiond_trace_chunk_registry_session_closed() methods create and | |
42 | * manage the reference count of lttng_trace_chunk_registry objects | |
43 | * associated to the various sessiond instances served by the relay daemon. | |
44 | * | |
45 | * When all sessions associated with a given sessiond instance are | |
46 | * destroyed, its registry is destroyed. | |
47 | * | |
48 | * lttng_trace_chunk objects are uniquely identified by the | |
49 | * (sessiond_uuid, sessiond_session_id, chunk_id) tuple. If a trace chunk | |
50 | * matching that tuple already exists, a new reference to the trace chunk | |
51 | * is acquired and it is returned to the caller. Otherwise, a new trace | |
52 | * chunk is created. This is how trace chunks are de-duplicated across | |
53 | * multiple consumer daemons managed by the same session daemon. | |
54 | * | |
55 | * Note that trace chunks are always added to their matching | |
56 | * lttng_trace_chunk_registry. They are automatically removed from the | |
57 | * trace chunk registry when their reference count reaches zero. | |
58 | */ | |
59 | ||
60 | /* | |
61 | * It is assumed that the sessiond_trace_chunk_registry is created and | |
62 | * destroyed by the same thread. | |
63 | */ | |
64 | struct sessiond_trace_chunk_registry { | |
65 | /* Maps an lttng_uuid to an lttng_trace_chunk_registry. */ | |
66 | struct cds_lfht *ht; | |
67 | }; | |
68 | ||
69 | struct trace_chunk_registry_ht_key { | |
70 | lttng_uuid sessiond_uuid; | |
71 | }; | |
72 | ||
73 | struct trace_chunk_registry_ht_element { | |
74 | struct trace_chunk_registry_ht_key key; | |
75 | struct urcu_ref ref; | |
76 | /* Node into the sessiond_trace_chunk_registry's hash table. */ | |
77 | struct cds_lfht_node ht_node; | |
78 | /* Used for defered call_rcu reclaim. */ | |
79 | struct rcu_head rcu_node; | |
80 | struct lttng_trace_chunk_registry *trace_chunk_registry; | |
81 | struct sessiond_trace_chunk_registry *sessiond_trace_chunk_registry; | |
82 | }; | |
83 | ||
84 | static | |
85 | unsigned long trace_chunk_registry_ht_key_hash( | |
86 | const struct trace_chunk_registry_ht_key *key) | |
87 | { | |
88 | uint64_t uuid_h1 = ((uint64_t *) key->sessiond_uuid)[0]; | |
89 | uint64_t uuid_h2 = ((uint64_t *) key->sessiond_uuid)[1]; | |
90 | ||
91 | return hash_key_u64(&uuid_h1, lttng_ht_seed) ^ | |
92 | hash_key_u64(&uuid_h2, lttng_ht_seed); | |
93 | } | |
94 | ||
95 | /* cds_lfht match function */ | |
96 | static | |
97 | int trace_chunk_registry_ht_key_match(struct cds_lfht_node *node, | |
98 | const void *_key) | |
99 | { | |
100 | const struct trace_chunk_registry_ht_key *key = | |
101 | (struct trace_chunk_registry_ht_key *) _key; | |
102 | struct trace_chunk_registry_ht_element *registry; | |
103 | ||
104 | registry = container_of(node, typeof(*registry), ht_node); | |
105 | return lttng_uuid_is_equal(key->sessiond_uuid, | |
106 | registry->key.sessiond_uuid); | |
107 | } | |
108 | ||
109 | static | |
110 | void trace_chunk_registry_ht_element_free(struct rcu_head *node) | |
111 | { | |
112 | struct trace_chunk_registry_ht_element *element = | |
113 | container_of(node, typeof(*element), rcu_node); | |
114 | ||
0c1b0f77 JG |
115 | free(element); |
116 | } | |
117 | ||
118 | static | |
119 | void trace_chunk_registry_ht_element_release(struct urcu_ref *ref) | |
120 | { | |
121 | struct trace_chunk_registry_ht_element *element = | |
122 | container_of(ref, typeof(*element), ref); | |
123 | char uuid_str[UUID_STR_LEN]; | |
124 | ||
125 | lttng_uuid_to_str(element->key.sessiond_uuid, uuid_str); | |
126 | ||
127 | DBG("Destroying trace chunk registry associated to sessiond {%s}", | |
128 | uuid_str); | |
129 | if (element->sessiond_trace_chunk_registry) { | |
130 | /* Unpublish. */ | |
131 | rcu_read_lock(); | |
132 | cds_lfht_del(element->sessiond_trace_chunk_registry->ht, | |
133 | &element->ht_node); | |
134 | rcu_read_unlock(); | |
135 | element->sessiond_trace_chunk_registry = NULL; | |
136 | } | |
137 | ||
c35f9726 | 138 | lttng_trace_chunk_registry_destroy(element->trace_chunk_registry); |
0c1b0f77 JG |
139 | /* Defered reclaim of the object */ |
140 | call_rcu(&element->rcu_node, trace_chunk_registry_ht_element_free); | |
141 | } | |
142 | ||
143 | static | |
144 | bool trace_chunk_registry_ht_element_get( | |
145 | struct trace_chunk_registry_ht_element *element) | |
146 | { | |
147 | return urcu_ref_get_unless_zero(&element->ref); | |
148 | } | |
149 | ||
150 | static | |
151 | void trace_chunk_registry_ht_element_put( | |
152 | struct trace_chunk_registry_ht_element *element) | |
153 | { | |
154 | urcu_ref_put(&element->ref, trace_chunk_registry_ht_element_release); | |
155 | } | |
156 | ||
157 | /* Acquires a reference to the returned element on behalf of the caller. */ | |
158 | static | |
159 | struct trace_chunk_registry_ht_element *trace_chunk_registry_ht_element_find( | |
160 | struct sessiond_trace_chunk_registry *sessiond_registry, | |
161 | const struct trace_chunk_registry_ht_key *key) | |
162 | { | |
163 | struct trace_chunk_registry_ht_element *element = NULL; | |
164 | struct cds_lfht_node *node; | |
165 | struct cds_lfht_iter iter; | |
166 | ||
167 | rcu_read_lock(); | |
168 | cds_lfht_lookup(sessiond_registry->ht, | |
169 | trace_chunk_registry_ht_key_hash(key), | |
170 | trace_chunk_registry_ht_key_match, | |
171 | key, | |
172 | &iter); | |
173 | node = cds_lfht_iter_get_node(&iter); | |
174 | if (node) { | |
175 | element = container_of(node, typeof(*element), ht_node); | |
176 | /* | |
177 | * Only consider the look-up as successful if a reference | |
178 | * could be acquired. | |
179 | */ | |
180 | if (!trace_chunk_registry_ht_element_get(element)) { | |
181 | element = NULL; | |
182 | } | |
183 | } | |
184 | rcu_read_unlock(); | |
185 | return element; | |
186 | } | |
187 | ||
188 | static | |
189 | int trace_chunk_registry_ht_element_create( | |
190 | struct sessiond_trace_chunk_registry *sessiond_registry, | |
191 | const struct trace_chunk_registry_ht_key *key) | |
192 | { | |
193 | int ret = 0; | |
194 | struct trace_chunk_registry_ht_element *new_element; | |
195 | struct lttng_trace_chunk_registry *trace_chunk_registry; | |
196 | char uuid_str[UUID_STR_LEN]; | |
197 | ||
198 | lttng_uuid_to_str(key->sessiond_uuid, uuid_str); | |
199 | ||
200 | trace_chunk_registry = lttng_trace_chunk_registry_create(); | |
201 | if (!trace_chunk_registry) { | |
202 | ret = -1; | |
203 | goto end; | |
204 | } | |
205 | ||
206 | new_element = zmalloc(sizeof(*new_element)); | |
207 | if (!new_element) { | |
208 | ret = -1; | |
209 | goto end; | |
210 | } | |
211 | ||
212 | memcpy(&new_element->key, key, sizeof(new_element->key)); | |
213 | urcu_ref_init(&new_element->ref); | |
214 | cds_lfht_node_init(&new_element->ht_node); | |
215 | new_element->trace_chunk_registry = trace_chunk_registry; | |
216 | ||
217 | /* Attempt to publish the new element. */ | |
218 | rcu_read_lock(); | |
219 | while (1) { | |
220 | struct cds_lfht_node *published_node; | |
221 | struct trace_chunk_registry_ht_element *published_element; | |
222 | ||
223 | published_node = cds_lfht_add_unique(sessiond_registry->ht, | |
224 | trace_chunk_registry_ht_key_hash(&new_element->key), | |
225 | trace_chunk_registry_ht_key_match, | |
226 | &new_element->key, | |
227 | &new_element->ht_node); | |
228 | if (published_node == &new_element->ht_node) { | |
229 | /* New element published successfully. */ | |
230 | DBG("Created trace chunk registry for sessiond {%s}", | |
231 | uuid_str); | |
232 | new_element->sessiond_trace_chunk_registry = | |
233 | sessiond_registry; | |
234 | break; | |
235 | } | |
236 | ||
237 | /* | |
238 | * An equivalent element was published during the creation of | |
239 | * this element. Attempt to acquire a reference to the one that | |
240 | * was already published and release the reference to the copy | |
241 | * we created if successful. | |
242 | */ | |
243 | published_element = container_of(published_node, | |
244 | typeof(*published_element), ht_node); | |
245 | if (trace_chunk_registry_ht_element_get(published_element)) { | |
246 | DBG("Acquired reference to trace chunk registry of sessiond {%s}", | |
247 | uuid_str); | |
248 | trace_chunk_registry_ht_element_put(new_element); | |
249 | new_element = NULL; | |
250 | break; | |
251 | } | |
252 | /* | |
253 | * A reference to the previously published element could not | |
254 | * be acquired. Hence, retry to publish our copy of the | |
255 | * element. | |
256 | */ | |
257 | } | |
258 | rcu_read_unlock(); | |
259 | end: | |
260 | if (ret < 0) { | |
261 | ERR("Failed to create trace chunk registry for session daemon {%s}", | |
262 | uuid_str); | |
263 | } | |
264 | return ret; | |
265 | } | |
266 | ||
267 | struct sessiond_trace_chunk_registry *sessiond_trace_chunk_registry_create(void) | |
268 | { | |
269 | struct sessiond_trace_chunk_registry *sessiond_registry = | |
270 | zmalloc(sizeof(*sessiond_registry)); | |
271 | ||
272 | if (!sessiond_registry) { | |
273 | goto end; | |
274 | } | |
275 | ||
276 | sessiond_registry->ht = cds_lfht_new(DEFAULT_HT_SIZE, | |
277 | 1, 0, CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL); | |
278 | if (!sessiond_registry->ht) { | |
279 | goto error; | |
280 | } | |
281 | ||
282 | end: | |
283 | return sessiond_registry; | |
284 | error: | |
285 | sessiond_trace_chunk_registry_destroy(sessiond_registry); | |
286 | return NULL; | |
287 | } | |
288 | ||
289 | void sessiond_trace_chunk_registry_destroy( | |
290 | struct sessiond_trace_chunk_registry *sessiond_registry) | |
291 | { | |
292 | int ret = cds_lfht_destroy(sessiond_registry->ht, NULL); | |
293 | ||
294 | assert(!ret); | |
295 | free(sessiond_registry); | |
296 | } | |
297 | ||
298 | int sessiond_trace_chunk_registry_session_created( | |
299 | struct sessiond_trace_chunk_registry *sessiond_registry, | |
300 | const lttng_uuid sessiond_uuid) | |
301 | { | |
302 | int ret = 0; | |
303 | struct trace_chunk_registry_ht_key key; | |
304 | struct trace_chunk_registry_ht_element *element; | |
305 | ||
306 | lttng_uuid_copy(key.sessiond_uuid, sessiond_uuid); | |
307 | ||
308 | element = trace_chunk_registry_ht_element_find(sessiond_registry, &key); | |
309 | if (element) { | |
310 | char uuid_str[UUID_STR_LEN]; | |
311 | ||
312 | lttng_uuid_to_str(sessiond_uuid, uuid_str); | |
313 | DBG("Acquired reference to trace chunk registry of sessiond {%s}", | |
314 | uuid_str); | |
315 | goto end; | |
316 | } else { | |
317 | ret = trace_chunk_registry_ht_element_create( | |
318 | sessiond_registry, &key); | |
319 | } | |
320 | end: | |
321 | return ret; | |
322 | } | |
323 | ||
324 | int sessiond_trace_chunk_registry_session_destroyed( | |
325 | struct sessiond_trace_chunk_registry *sessiond_registry, | |
326 | const lttng_uuid sessiond_uuid) | |
327 | { | |
328 | int ret = 0; | |
329 | struct trace_chunk_registry_ht_key key; | |
330 | struct trace_chunk_registry_ht_element *element; | |
331 | char uuid_str[UUID_STR_LEN]; | |
332 | ||
333 | lttng_uuid_to_str(sessiond_uuid, uuid_str); | |
334 | lttng_uuid_copy(key.sessiond_uuid, sessiond_uuid); | |
335 | ||
336 | element = trace_chunk_registry_ht_element_find(sessiond_registry, &key); | |
337 | if (element) { | |
338 | DBG("Releasing reference to trace chunk registry of sessiond {%s}", | |
339 | uuid_str); | |
340 | /* | |
341 | * Release the reference held by the session and the reference | |
342 | * acquired through the "find" operation. | |
343 | */ | |
344 | trace_chunk_registry_ht_element_put(element); | |
345 | trace_chunk_registry_ht_element_put(element); | |
346 | } else { | |
347 | ERR("Failed to find trace chunk registry of sessiond {%s}", | |
348 | uuid_str); | |
349 | ret = -1; | |
350 | } | |
351 | return ret; | |
352 | } | |
353 | ||
354 | struct lttng_trace_chunk *sessiond_trace_chunk_registry_publish_chunk( | |
355 | struct sessiond_trace_chunk_registry *sessiond_registry, | |
356 | const lttng_uuid sessiond_uuid, uint64_t session_id, | |
357 | struct lttng_trace_chunk *new_chunk) | |
358 | { | |
359 | enum lttng_trace_chunk_status status; | |
360 | uint64_t chunk_id; | |
361 | bool is_anonymous_chunk; | |
362 | struct trace_chunk_registry_ht_key key; | |
363 | struct trace_chunk_registry_ht_element *element = NULL; | |
364 | char uuid_str[UUID_STR_LEN]; | |
365 | char chunk_id_str[MAX_INT_DEC_LEN(typeof(chunk_id))] = "-1"; | |
366 | struct lttng_trace_chunk *published_chunk = NULL; | |
367 | ||
368 | lttng_uuid_to_str(sessiond_uuid, uuid_str); | |
369 | lttng_uuid_copy(key.sessiond_uuid, sessiond_uuid); | |
370 | ||
371 | status = lttng_trace_chunk_get_id(new_chunk, &chunk_id); | |
372 | if (status == LTTNG_TRACE_CHUNK_STATUS_OK) { | |
373 | int ret; | |
374 | ||
375 | ret = snprintf(chunk_id_str, sizeof(chunk_id_str), "%" PRIu64, | |
376 | chunk_id); | |
377 | if (ret < 0) { | |
378 | lttng_strncpy(chunk_id_str, "-1", sizeof(chunk_id_str)); | |
379 | WARN("Failed to format trace chunk id"); | |
380 | } | |
381 | is_anonymous_chunk = false; | |
382 | } else if (status == LTTNG_TRACE_CHUNK_STATUS_NONE) { | |
383 | is_anonymous_chunk = true; | |
384 | } else { | |
385 | ERR("Failed to get trace chunk id"); | |
386 | goto end; | |
387 | } | |
388 | ||
389 | DBG("Attempting to publish trace chunk: sessiond {%s}, session_id = " | |
390 | "%" PRIu64 ", chunk_id = %s", | |
391 | uuid_str, session_id, | |
392 | is_anonymous_chunk ? "anonymous" : chunk_id_str); | |
393 | ||
394 | element = trace_chunk_registry_ht_element_find(sessiond_registry, &key); | |
395 | if (!element) { | |
396 | ERR("Failed to find registry of sessiond {%s}", uuid_str); | |
397 | goto end; | |
398 | } | |
399 | ||
400 | published_chunk = lttng_trace_chunk_registry_publish_chunk( | |
401 | element->trace_chunk_registry, session_id, new_chunk); | |
c35f9726 JG |
402 | /* |
403 | * At this point, two references to the published chunks exist. One | |
404 | * is taken by the registry while the other is being returned to the | |
405 | * caller. In the use case of the relay daemon, the reference held | |
406 | * by the registry itself is undesirable. | |
407 | * | |
408 | * We want the trace chunk to be removed from the registry as soon | |
409 | * as it is not being used by the relay daemon (through a session | |
410 | * or a stream). This differs from the behaviour of the consumer | |
411 | * daemon which relies on an explicit command from the session | |
412 | * daemon to release the registry's reference. | |
413 | */ | |
414 | lttng_trace_chunk_put(published_chunk); | |
0c1b0f77 JG |
415 | end: |
416 | trace_chunk_registry_ht_element_put(element); | |
417 | return published_chunk; | |
418 | } | |
419 | ||
420 | struct lttng_trace_chunk * | |
421 | sessiond_trace_chunk_registry_get_anonymous_chunk( | |
422 | struct sessiond_trace_chunk_registry *sessiond_registry, | |
423 | const lttng_uuid sessiond_uuid, | |
424 | uint64_t session_id) | |
425 | { | |
426 | struct lttng_trace_chunk *chunk = NULL; | |
427 | struct trace_chunk_registry_ht_element *element; | |
428 | struct trace_chunk_registry_ht_key key; | |
429 | char uuid_str[UUID_STR_LEN]; | |
430 | ||
431 | lttng_uuid_to_str(sessiond_uuid, uuid_str); | |
432 | ||
433 | lttng_uuid_copy(key.sessiond_uuid, sessiond_uuid); | |
434 | element = trace_chunk_registry_ht_element_find(sessiond_registry, &key); | |
435 | if (!element) { | |
436 | ERR("Failed to find trace chunk registry of sessiond {%s}", | |
437 | uuid_str); | |
438 | goto end; | |
439 | } | |
440 | ||
441 | chunk = lttng_trace_chunk_registry_find_anonymous_chunk( | |
442 | element->trace_chunk_registry, | |
443 | session_id); | |
444 | trace_chunk_registry_ht_element_put(element); | |
445 | end: | |
446 | return chunk; | |
447 | } | |
448 | ||
449 | struct lttng_trace_chunk * | |
450 | sessiond_trace_chunk_registry_get_chunk( | |
451 | struct sessiond_trace_chunk_registry *sessiond_registry, | |
452 | const lttng_uuid sessiond_uuid, | |
453 | uint64_t session_id, uint64_t chunk_id) | |
454 | { | |
455 | struct lttng_trace_chunk *chunk = NULL; | |
456 | struct trace_chunk_registry_ht_element *element; | |
457 | struct trace_chunk_registry_ht_key key; | |
458 | char uuid_str[UUID_STR_LEN]; | |
459 | ||
460 | lttng_uuid_to_str(sessiond_uuid, uuid_str); | |
461 | ||
462 | lttng_uuid_copy(key.sessiond_uuid, sessiond_uuid); | |
463 | element = trace_chunk_registry_ht_element_find(sessiond_registry, &key); | |
464 | if (!element) { | |
465 | ERR("Failed to find trace chunk registry of sessiond {%s}", | |
466 | uuid_str); | |
467 | goto end; | |
468 | } | |
469 | ||
470 | chunk = lttng_trace_chunk_registry_find_chunk( | |
471 | element->trace_chunk_registry, | |
472 | session_id, chunk_id); | |
473 | trace_chunk_registry_ht_element_put(element); | |
474 | end: | |
475 | return chunk; | |
476 | } |