| 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 | * Reset the metadata cache. |
| 75 | */ |
| 76 | static |
| 77 | void metadata_cache_reset(struct consumer_metadata_cache *cache) |
| 78 | { |
| 79 | memset(cache->data, 0, cache->cache_alloc_size); |
| 80 | cache->max_offset = 0; |
| 81 | } |
| 82 | |
| 83 | /* |
| 84 | * Check if the metadata cache version changed. |
| 85 | * If it did, reset the metadata cache. |
| 86 | * The metadata cache lock MUST be held. |
| 87 | * |
| 88 | * Returns 0 on success, a negative value on error. |
| 89 | */ |
| 90 | static |
| 91 | int metadata_cache_check_version(struct consumer_metadata_cache *cache, |
| 92 | uint64_t version) |
| 93 | { |
| 94 | int ret = 0; |
| 95 | |
| 96 | if (cache->version == version) { |
| 97 | goto end; |
| 98 | } |
| 99 | |
| 100 | DBG("Metadata cache version update to %" PRIu64, version); |
| 101 | metadata_cache_reset(cache); |
| 102 | cache->version = version; |
| 103 | |
| 104 | end: |
| 105 | return ret; |
| 106 | } |
| 107 | |
| 108 | /* |
| 109 | * Write a character on the metadata poll pipe to wake the metadata thread. |
| 110 | * Returns 0 on success, -1 on error. |
| 111 | */ |
| 112 | int consumer_metadata_wakeup_pipe(const struct lttng_consumer_channel *channel) |
| 113 | { |
| 114 | int ret = 0; |
| 115 | const char dummy = 'c'; |
| 116 | |
| 117 | if (channel->monitor && channel->metadata_stream) { |
| 118 | ssize_t write_ret; |
| 119 | |
| 120 | write_ret = lttng_write(channel->metadata_stream->ust_metadata_poll_pipe[1], |
| 121 | &dummy, 1); |
| 122 | if (write_ret < 1) { |
| 123 | if (errno == EWOULDBLOCK) { |
| 124 | /* |
| 125 | * This is fine, the metadata poll thread |
| 126 | * is having a hard time keeping-up, but |
| 127 | * it will eventually wake-up and consume |
| 128 | * the available data. |
| 129 | */ |
| 130 | ret = 0; |
| 131 | } else { |
| 132 | PERROR("Wake-up UST metadata pipe"); |
| 133 | ret = -1; |
| 134 | goto end; |
| 135 | } |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | end: |
| 140 | return ret; |
| 141 | } |
| 142 | |
| 143 | /* |
| 144 | * Write metadata to the cache, extend the cache if necessary. We support |
| 145 | * overlapping updates, but they need to be contiguous. Send the |
| 146 | * contiguous metadata in cache to the ring buffer. The metadata cache |
| 147 | * lock MUST be acquired to write in the cache. |
| 148 | * |
| 149 | * Return 0 on success, a negative value on error. |
| 150 | */ |
| 151 | int consumer_metadata_cache_write(struct lttng_consumer_channel *channel, |
| 152 | unsigned int offset, unsigned int len, uint64_t version, |
| 153 | char *data) |
| 154 | { |
| 155 | int ret = 0; |
| 156 | struct consumer_metadata_cache *cache; |
| 157 | |
| 158 | assert(channel); |
| 159 | assert(channel->metadata_cache); |
| 160 | |
| 161 | cache = channel->metadata_cache; |
| 162 | |
| 163 | ret = metadata_cache_check_version(cache, version); |
| 164 | if (ret < 0) { |
| 165 | goto end; |
| 166 | } |
| 167 | |
| 168 | DBG("Writing %u bytes from offset %u in metadata cache", len, offset); |
| 169 | |
| 170 | if (offset + len > cache->cache_alloc_size) { |
| 171 | ret = extend_metadata_cache(channel, |
| 172 | len - cache->cache_alloc_size + offset); |
| 173 | if (ret < 0) { |
| 174 | ERR("Extending metadata cache"); |
| 175 | goto end; |
| 176 | } |
| 177 | } |
| 178 | |
| 179 | memcpy(cache->data + offset, data, len); |
| 180 | if (offset + len > cache->max_offset) { |
| 181 | cache->max_offset = offset + len; |
| 182 | ret = consumer_metadata_wakeup_pipe(channel); |
| 183 | } |
| 184 | |
| 185 | end: |
| 186 | return ret; |
| 187 | } |
| 188 | |
| 189 | /* |
| 190 | * Create the metadata cache, original allocated size: max_sb_size |
| 191 | * |
| 192 | * Return 0 on success, a negative value on error. |
| 193 | */ |
| 194 | int consumer_metadata_cache_allocate(struct lttng_consumer_channel *channel) |
| 195 | { |
| 196 | int ret; |
| 197 | |
| 198 | assert(channel); |
| 199 | |
| 200 | channel->metadata_cache = zmalloc( |
| 201 | sizeof(struct consumer_metadata_cache)); |
| 202 | if (!channel->metadata_cache) { |
| 203 | PERROR("zmalloc metadata cache struct"); |
| 204 | ret = -1; |
| 205 | goto end; |
| 206 | } |
| 207 | ret = pthread_mutex_init(&channel->metadata_cache->lock, NULL); |
| 208 | if (ret != 0) { |
| 209 | PERROR("mutex init"); |
| 210 | goto end_free_cache; |
| 211 | } |
| 212 | |
| 213 | channel->metadata_cache->cache_alloc_size = DEFAULT_METADATA_CACHE_SIZE; |
| 214 | channel->metadata_cache->data = zmalloc( |
| 215 | channel->metadata_cache->cache_alloc_size * sizeof(char)); |
| 216 | if (!channel->metadata_cache->data) { |
| 217 | PERROR("zmalloc metadata cache data"); |
| 218 | ret = -1; |
| 219 | goto end_free_mutex; |
| 220 | } |
| 221 | DBG("Allocated metadata cache of %" PRIu64 " bytes", |
| 222 | channel->metadata_cache->cache_alloc_size); |
| 223 | |
| 224 | ret = 0; |
| 225 | goto end; |
| 226 | |
| 227 | end_free_mutex: |
| 228 | pthread_mutex_destroy(&channel->metadata_cache->lock); |
| 229 | end_free_cache: |
| 230 | free(channel->metadata_cache); |
| 231 | end: |
| 232 | return ret; |
| 233 | } |
| 234 | |
| 235 | /* |
| 236 | * Destroy and free the metadata cache |
| 237 | */ |
| 238 | void consumer_metadata_cache_destroy(struct lttng_consumer_channel *channel) |
| 239 | { |
| 240 | if (!channel || !channel->metadata_cache) { |
| 241 | return; |
| 242 | } |
| 243 | |
| 244 | DBG("Destroying metadata cache"); |
| 245 | |
| 246 | pthread_mutex_destroy(&channel->metadata_cache->lock); |
| 247 | free(channel->metadata_cache->data); |
| 248 | free(channel->metadata_cache); |
| 249 | } |
| 250 | |
| 251 | /* |
| 252 | * Check if the cache is flushed up to the offset passed in parameter. |
| 253 | * |
| 254 | * Return 0 if everything has been flushed, 1 if there is data not flushed. |
| 255 | */ |
| 256 | int consumer_metadata_cache_flushed(struct lttng_consumer_channel *channel, |
| 257 | uint64_t offset, int timer) |
| 258 | { |
| 259 | int ret = 0; |
| 260 | struct lttng_consumer_stream *metadata_stream; |
| 261 | |
| 262 | assert(channel); |
| 263 | assert(channel->metadata_cache); |
| 264 | |
| 265 | /* |
| 266 | * If not called from a timer handler, we have to take the |
| 267 | * channel lock to be mutually exclusive with channel teardown. |
| 268 | * Timer handler does not need to take this lock because it is |
| 269 | * already synchronized by timer stop (and, more importantly, |
| 270 | * taking this lock in a timer handler would cause a deadlock). |
| 271 | */ |
| 272 | if (!timer) { |
| 273 | pthread_mutex_lock(&channel->lock); |
| 274 | } |
| 275 | pthread_mutex_lock(&channel->timer_lock); |
| 276 | metadata_stream = channel->metadata_stream; |
| 277 | pthread_mutex_lock(&metadata_stream->lock); |
| 278 | pthread_mutex_lock(&channel->metadata_cache->lock); |
| 279 | |
| 280 | if (!metadata_stream) { |
| 281 | /* |
| 282 | * Having no metadata stream means the channel is being destroyed so there |
| 283 | * is no cache to flush anymore. |
| 284 | */ |
| 285 | ret = 0; |
| 286 | } else if (metadata_stream->ust_metadata_pushed >= offset) { |
| 287 | ret = 0; |
| 288 | } else if (channel->metadata_stream->endpoint_status != |
| 289 | CONSUMER_ENDPOINT_ACTIVE) { |
| 290 | /* An inactive endpoint means we don't have to flush anymore. */ |
| 291 | ret = 0; |
| 292 | } else { |
| 293 | /* Still not completely flushed. */ |
| 294 | ret = 1; |
| 295 | } |
| 296 | |
| 297 | pthread_mutex_unlock(&channel->metadata_cache->lock); |
| 298 | pthread_mutex_unlock(&metadata_stream->lock); |
| 299 | pthread_mutex_unlock(&channel->timer_lock); |
| 300 | if (!timer) { |
| 301 | pthread_mutex_unlock(&channel->lock); |
| 302 | } |
| 303 | |
| 304 | return ret; |
| 305 | } |