consumerd: move rotation logic to domain-agnostic read path
[lttng-tools.git] / src / common / consumer / consumer-metadata-cache.c
CommitLineData
331744e3 1/*
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2 * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
3 * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
331744e3 4 *
ab5be9fa 5 * SPDX-License-Identifier: GPL-2.0-only
331744e3 6 *
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7 */
8
6c1c0768 9#define _LGPL_SOURCE
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10#include <assert.h>
11#include <pthread.h>
12#include <stdlib.h>
13#include <string.h>
14#include <sys/types.h>
15#include <unistd.h>
16#include <inttypes.h>
17
18#include <common/common.h>
19#include <common/utils.h>
20#include <common/sessiond-comm/sessiond-comm.h>
21#include <common/ust-consumer/ust-consumer.h>
c8fea79c 22#include <common/consumer/consumer.h>
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23
24#include "consumer-metadata-cache.h"
25
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26extern struct lttng_consumer_global_data consumer_data;
27
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28/*
29 * Extend the allocated size of the metadata cache. Called only from
30 * lttng_ustconsumer_write_metadata_cache.
31 *
32 * Return 0 on success, a negative value on error.
33 */
34static int extend_metadata_cache(struct lttng_consumer_channel *channel,
35 unsigned int size)
36{
37 int ret = 0;
38 char *tmp_data_ptr;
53efb85a 39 unsigned int new_size, old_size;
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40
41 assert(channel);
42 assert(channel->metadata_cache);
43
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44 old_size = channel->metadata_cache->cache_alloc_size;
45 new_size = max_t(unsigned int, old_size + size, old_size << 1);
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46 DBG("Extending metadata cache to %u", new_size);
47 tmp_data_ptr = realloc(channel->metadata_cache->data, new_size);
48 if (!tmp_data_ptr) {
49 ERR("Reallocating metadata cache");
50 free(channel->metadata_cache->data);
51 ret = -1;
52 goto end;
53 }
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54 /* Zero newly allocated memory */
55 memset(tmp_data_ptr + old_size, 0, new_size - old_size);
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56 channel->metadata_cache->data = tmp_data_ptr;
57 channel->metadata_cache->cache_alloc_size = new_size;
58
59end:
60 return ret;
61}
62
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63/*
64 * Reset the metadata cache.
65 */
66static
67void metadata_cache_reset(struct consumer_metadata_cache *cache)
68{
69 memset(cache->data, 0, cache->cache_alloc_size);
70 cache->max_offset = 0;
71}
72
73/*
74 * Check if the metadata cache version changed.
75 * If it did, reset the metadata cache.
76 * The metadata cache lock MUST be held.
77 *
78 * Returns 0 on success, a negative value on error.
79 */
80static
81int metadata_cache_check_version(struct consumer_metadata_cache *cache,
9dd04ae3 82 uint64_t version)
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83{
84 int ret = 0;
85
86 if (cache->version == version) {
87 goto end;
88 }
89
90 DBG("Metadata cache version update to %" PRIu64, version);
91 metadata_cache_reset(cache);
92 cache->version = version;
93
94end:
95 return ret;
96}
97
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98/*
99 * Write a character on the metadata poll pipe to wake the metadata thread.
100 * Returns 0 on success, -1 on error.
101 */
102int consumer_metadata_wakeup_pipe(const struct lttng_consumer_channel *channel)
103{
104 int ret = 0;
105 const char dummy = 'c';
106
107 if (channel->monitor && channel->metadata_stream) {
108 ssize_t write_ret;
109
110 write_ret = lttng_write(channel->metadata_stream->ust_metadata_poll_pipe[1],
111 &dummy, 1);
112 if (write_ret < 1) {
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113 if (errno == EWOULDBLOCK) {
114 /*
115 * This is fine, the metadata poll thread
116 * is having a hard time keeping-up, but
117 * it will eventually wake-up and consume
118 * the available data.
119 */
120 ret = 0;
121 } else {
122 PERROR("Wake-up UST metadata pipe");
123 ret = -1;
124 goto end;
125 }
126 }
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127 }
128
129end:
130 return ret;
131}
132
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133/*
134 * Write metadata to the cache, extend the cache if necessary. We support
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135 * overlapping updates, but they need to be contiguous. Send the
136 * contiguous metadata in cache to the ring buffer. The metadata cache
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137 * lock MUST be acquired to write in the cache.
138 *
139 * Return 0 on success, a negative value on error.
140 */
141int consumer_metadata_cache_write(struct lttng_consumer_channel *channel,
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142 unsigned int offset, unsigned int len, uint64_t version,
143 char *data)
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144{
145 int ret = 0;
146 struct consumer_metadata_cache *cache;
147
148 assert(channel);
149 assert(channel->metadata_cache);
150
151 cache = channel->metadata_cache;
93ec662e 152
9dd04ae3 153 ret = metadata_cache_check_version(cache, version);
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154 if (ret < 0) {
155 goto end;
156 }
157
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158 DBG("Writing %u bytes from offset %u in metadata cache", len, offset);
159
160 if (offset + len > cache->cache_alloc_size) {
161 ret = extend_metadata_cache(channel,
162 len - cache->cache_alloc_size + offset);
163 if (ret < 0) {
164 ERR("Extending metadata cache");
165 goto end;
166 }
167 }
168
169 memcpy(cache->data + offset, data, len);
331744e3 170 if (offset + len > cache->max_offset) {
c585821b 171 cache->max_offset = offset + len;
5b8eb761 172 ret = consumer_metadata_wakeup_pipe(channel);
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173 }
174
175end:
176 return ret;
177}
178
179/*
180 * Create the metadata cache, original allocated size: max_sb_size
181 *
182 * Return 0 on success, a negative value on error.
183 */
184int consumer_metadata_cache_allocate(struct lttng_consumer_channel *channel)
185{
186 int ret;
187
188 assert(channel);
189
190 channel->metadata_cache = zmalloc(
191 sizeof(struct consumer_metadata_cache));
192 if (!channel->metadata_cache) {
193 PERROR("zmalloc metadata cache struct");
194 ret = -1;
195 goto end;
196 }
197 ret = pthread_mutex_init(&channel->metadata_cache->lock, NULL);
198 if (ret != 0) {
199 PERROR("mutex init");
200 goto end_free_cache;
201 }
202
203 channel->metadata_cache->cache_alloc_size = DEFAULT_METADATA_CACHE_SIZE;
204 channel->metadata_cache->data = zmalloc(
205 channel->metadata_cache->cache_alloc_size * sizeof(char));
206 if (!channel->metadata_cache->data) {
207 PERROR("zmalloc metadata cache data");
208 ret = -1;
209 goto end_free_mutex;
210 }
211 DBG("Allocated metadata cache of %" PRIu64 " bytes",
212 channel->metadata_cache->cache_alloc_size);
213
214 ret = 0;
215 goto end;
216
217end_free_mutex:
218 pthread_mutex_destroy(&channel->metadata_cache->lock);
219end_free_cache:
220 free(channel->metadata_cache);
221end:
222 return ret;
223}
224
225/*
226 * Destroy and free the metadata cache
227 */
228void consumer_metadata_cache_destroy(struct lttng_consumer_channel *channel)
229{
230 if (!channel || !channel->metadata_cache) {
231 return;
232 }
233
234 DBG("Destroying metadata cache");
235
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236 pthread_mutex_destroy(&channel->metadata_cache->lock);
237 free(channel->metadata_cache->data);
238 free(channel->metadata_cache);
239}
240
241/*
242 * Check if the cache is flushed up to the offset passed in parameter.
243 *
244 * Return 0 if everything has been flushed, 1 if there is data not flushed.
245 */
246int consumer_metadata_cache_flushed(struct lttng_consumer_channel *channel,
5e41ebe1 247 uint64_t offset, int timer)
331744e3 248{
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249 int ret = 0;
250 struct lttng_consumer_stream *metadata_stream;
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251
252 assert(channel);
253 assert(channel->metadata_cache);
254
7f725ec5 255 /*
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256 * If not called from a timer handler, we have to take the
257 * channel lock to be mutually exclusive with channel teardown.
258 * Timer handler does not need to take this lock because it is
259 * already synchronized by timer stop (and, more importantly,
260 * taking this lock in a timer handler would cause a deadlock).
7f725ec5 261 */
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262 if (!timer) {
263 pthread_mutex_lock(&channel->lock);
264 }
ec6ea7d0 265 pthread_mutex_lock(&channel->timer_lock);
04ef1097 266 metadata_stream = channel->metadata_stream;
04ef1097 267 if (!metadata_stream) {
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268 /*
269 * Having no metadata stream means the channel is being destroyed so there
270 * is no cache to flush anymore.
271 */
272 ret = 0;
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273 goto end_unlock_channel;
274 }
275
276 pthread_mutex_lock(&metadata_stream->lock);
277 pthread_mutex_lock(&channel->metadata_cache->lock);
278
279 if (metadata_stream->ust_metadata_pushed >= offset) {
04ef1097 280 ret = 0;
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281 } else if (channel->metadata_stream->endpoint_status !=
282 CONSUMER_ENDPOINT_ACTIVE) {
283 /* An inactive endpoint means we don't have to flush anymore. */
284 ret = 0;
331744e3 285 } else {
fe81e5c9 286 /* Still not completely flushed. */
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287 ret = 1;
288 }
fe81e5c9 289
331744e3 290 pthread_mutex_unlock(&channel->metadata_cache->lock);
8e1ef46e 291 pthread_mutex_unlock(&metadata_stream->lock);
e524139e 292end_unlock_channel:
ec6ea7d0 293 pthread_mutex_unlock(&channel->timer_lock);
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294 if (!timer) {
295 pthread_mutex_unlock(&channel->lock);
296 }
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297
298 return ret;
299}
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