48257c299750aa0953016808766c6a634a17c65e
[lttng-tools.git] / src / common / consumer / consumer-metadata-cache.c
1 /*
2 * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
3 * David Goulet <dgoulet@efficios.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License, version 2 only,
7 * as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
12 * more details.
13 *
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
17 */
18
19 #define _LGPL_SOURCE
20 #include <assert.h>
21 #include <pthread.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <sys/types.h>
25 #include <unistd.h>
26 #include <inttypes.h>
27
28 #include <common/common.h>
29 #include <common/utils.h>
30 #include <common/sessiond-comm/sessiond-comm.h>
31 #include <common/ust-consumer/ust-consumer.h>
32 #include <common/consumer/consumer.h>
33
34 #include "consumer-metadata-cache.h"
35
36 extern struct lttng_consumer_global_data consumer_data;
37
38 /*
39 * Extend the allocated size of the metadata cache. Called only from
40 * lttng_ustconsumer_write_metadata_cache.
41 *
42 * Return 0 on success, a negative value on error.
43 */
44 static int extend_metadata_cache(struct lttng_consumer_channel *channel,
45 unsigned int size)
46 {
47 int ret = 0;
48 char *tmp_data_ptr;
49 unsigned int new_size, old_size;
50
51 assert(channel);
52 assert(channel->metadata_cache);
53
54 old_size = channel->metadata_cache->cache_alloc_size;
55 new_size = max_t(unsigned int, old_size + size, old_size << 1);
56 DBG("Extending metadata cache to %u", new_size);
57 tmp_data_ptr = realloc(channel->metadata_cache->data, new_size);
58 if (!tmp_data_ptr) {
59 ERR("Reallocating metadata cache");
60 free(channel->metadata_cache->data);
61 ret = -1;
62 goto end;
63 }
64 /* Zero newly allocated memory */
65 memset(tmp_data_ptr + old_size, 0, new_size - old_size);
66 channel->metadata_cache->data = tmp_data_ptr;
67 channel->metadata_cache->cache_alloc_size = new_size;
68
69 end:
70 return ret;
71 }
72
73 /*
74 * Write metadata to the cache, extend the cache if necessary. We support
75 * overlapping updates, but they need to be contiguous. Send the
76 * contiguous metadata in cache to the ring buffer. The metadata cache
77 * lock MUST be acquired to write in the cache.
78 *
79 * Return 0 on success, a negative value on error.
80 */
81 int consumer_metadata_cache_write(struct lttng_consumer_channel *channel,
82 unsigned int offset, unsigned int len, char *data)
83 {
84 int ret = 0;
85 int size_ret;
86 struct consumer_metadata_cache *cache;
87
88 assert(channel);
89 assert(channel->metadata_cache);
90
91 cache = channel->metadata_cache;
92 DBG("Writing %u bytes from offset %u in metadata cache", len, offset);
93
94 if (offset + len > cache->cache_alloc_size) {
95 ret = extend_metadata_cache(channel,
96 len - cache->cache_alloc_size + offset);
97 if (ret < 0) {
98 ERR("Extending metadata cache");
99 goto end;
100 }
101 }
102
103 memcpy(cache->data + offset, data, len);
104 if (offset + len > cache->max_offset) {
105 char dummy = 'c';
106
107 cache->max_offset = offset + len;
108 if (channel->monitor) {
109 size_ret = lttng_write(channel->metadata_stream->ust_metadata_poll_pipe[1],
110 &dummy, 1);
111 if (size_ret < 1) {
112 ERR("Wakeup UST metadata pipe");
113 ret = -1;
114 goto end;
115 }
116 }
117 }
118
119 end:
120 return ret;
121 }
122
123 /*
124 * Create the metadata cache, original allocated size: max_sb_size
125 *
126 * Return 0 on success, a negative value on error.
127 */
128 int consumer_metadata_cache_allocate(struct lttng_consumer_channel *channel)
129 {
130 int ret;
131
132 assert(channel);
133
134 channel->metadata_cache = zmalloc(
135 sizeof(struct consumer_metadata_cache));
136 if (!channel->metadata_cache) {
137 PERROR("zmalloc metadata cache struct");
138 ret = -1;
139 goto end;
140 }
141 ret = pthread_mutex_init(&channel->metadata_cache->lock, NULL);
142 if (ret != 0) {
143 PERROR("mutex init");
144 goto end_free_cache;
145 }
146
147 channel->metadata_cache->cache_alloc_size = DEFAULT_METADATA_CACHE_SIZE;
148 channel->metadata_cache->data = zmalloc(
149 channel->metadata_cache->cache_alloc_size * sizeof(char));
150 if (!channel->metadata_cache->data) {
151 PERROR("zmalloc metadata cache data");
152 ret = -1;
153 goto end_free_mutex;
154 }
155 DBG("Allocated metadata cache of %" PRIu64 " bytes",
156 channel->metadata_cache->cache_alloc_size);
157
158 ret = 0;
159 goto end;
160
161 end_free_mutex:
162 pthread_mutex_destroy(&channel->metadata_cache->lock);
163 end_free_cache:
164 free(channel->metadata_cache);
165 end:
166 return ret;
167 }
168
169 /*
170 * Destroy and free the metadata cache
171 */
172 void consumer_metadata_cache_destroy(struct lttng_consumer_channel *channel)
173 {
174 if (!channel || !channel->metadata_cache) {
175 return;
176 }
177
178 DBG("Destroying metadata cache");
179
180 pthread_mutex_destroy(&channel->metadata_cache->lock);
181 free(channel->metadata_cache->data);
182 free(channel->metadata_cache);
183 }
184
185 /*
186 * Check if the cache is flushed up to the offset passed in parameter.
187 *
188 * Return 0 if everything has been flushed, 1 if there is data not flushed.
189 */
190 int consumer_metadata_cache_flushed(struct lttng_consumer_channel *channel,
191 uint64_t offset, int timer)
192 {
193 int ret = 0;
194 struct lttng_consumer_stream *metadata_stream;
195
196 assert(channel);
197 assert(channel->metadata_cache);
198
199 /*
200 * If not called from a timer handler, we have to take the
201 * channel lock to be mutually exclusive with channel teardown.
202 * Timer handler does not need to take this lock because it is
203 * already synchronized by timer stop (and, more importantly,
204 * taking this lock in a timer handler would cause a deadlock).
205 */
206 if (!timer) {
207 pthread_mutex_lock(&channel->lock);
208 }
209 pthread_mutex_lock(&channel->timer_lock);
210 pthread_mutex_lock(&channel->metadata_cache->lock);
211
212 metadata_stream = channel->metadata_stream;
213
214 if (!metadata_stream) {
215 /*
216 * Having no metadata stream means the channel is being destroyed so there
217 * is no cache to flush anymore.
218 */
219 ret = 0;
220 } else if (metadata_stream->ust_metadata_pushed >= offset) {
221 ret = 0;
222 } else if (channel->metadata_stream->endpoint_status !=
223 CONSUMER_ENDPOINT_ACTIVE) {
224 /* An inactive endpoint means we don't have to flush anymore. */
225 ret = 0;
226 } else {
227 /* Still not completely flushed. */
228 ret = 1;
229 }
230
231 pthread_mutex_unlock(&channel->metadata_cache->lock);
232 pthread_mutex_unlock(&channel->timer_lock);
233 if (!timer) {
234 pthread_mutex_unlock(&channel->lock);
235 }
236
237 return ret;
238 }
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