liblttng-ust/lttng-ring-buffer-client.h

   1 /*
   2  * lttng-ring-buffer-client.h
   3  *
   4  * LTTng lib ring buffer client template.
   5  *
   6  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include <stdint.h>
  24 #include <lttng/ust-events.h>
  25 #include "lttng/bitfield.h"
  26 #include "clock.h"
  27 #include "lttng-tracer.h"
  28 #include "../libringbuffer/frontend_types.h"
  29
  30 #define LTTNG_COMPACT_EVENT_BITS       5
  31 #define LTTNG_COMPACT_TSC_BITS         27
  32
  33 /*
  34  * Keep the natural field alignment for _each field_ within this structure if
  35  * you ever add/remove a field from this header. Packed attribute is not used
  36  * because gcc generates poor code on at least powerpc and mips. Don't ever
  37  * let gcc add padding between the structure elements.
  38  */
  39
  40 struct packet_header {
  41         /* Trace packet header */
  42         uint32_t magic;                 /*
  43                                          * Trace magic number.
  44                                          * contains endianness information.
  45                                          */
  46         uint8_t uuid[LTTNG_UST_UUID_LEN];
  47         uint32_t stream_id;
  48
  49         struct {
  50                 /* Stream packet context */
  51                 uint64_t timestamp_begin;       /* Cycle count at subbuffer start */
  52                 uint64_t timestamp_end;         /* Cycle count at subbuffer end */
  53                 uint64_t content_size;          /* Size of data in subbuffer */
  54                 uint64_t packet_size;           /* Subbuffer size (include padding) */
  55                 unsigned long events_discarded; /*
  56                                                  * Events lost in this subbuffer since
  57                                                  * the beginning of the trace.
  58                                                  * (may overflow)
  59                                                  */
  60                 uint32_t cpu_id;                /* CPU id associated with stream */
  61                 uint8_t header_end;             /* End of header */
  62         } ctx;
  63 };
  64
  65
  66 static inline uint64_t lib_ring_buffer_clock_read(struct channel *chan)
  67 {
  68         return trace_clock_read64();
  69 }
  70
  71 static inline
  72 size_t ctx_get_size(size_t offset, struct lttng_ctx *ctx)
  73 {
  74         int i;
  75         size_t orig_offset = offset;
  76
  77         if (caa_likely(!ctx))
  78                 return 0;
  79         for (i = 0; i < ctx->nr_fields; i++)
  80                 offset += ctx->fields[i].get_size(offset);
  81         return offset - orig_offset;
  82 }
  83
  84 static inline
  85 void ctx_record(struct lttng_ust_lib_ring_buffer_ctx *bufctx,
  86                 struct lttng_channel *chan,
  87                 struct lttng_ctx *ctx)
  88 {
  89         int i;
  90
  91         if (caa_likely(!ctx))
  92                 return;
  93         for (i = 0; i < ctx->nr_fields; i++)
  94                 ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
  95 }
  96
  97 /*
  98  * record_header_size - Calculate the header size and padding necessary.
  99  * @config: ring buffer instance configuration
 100  * @chan: channel
 101  * @offset: offset in the write buffer
 102  * @pre_header_padding: padding to add before the header (output)
 103  * @ctx: reservation context
 104  *
 105  * Returns the event header size (including padding).
 106  *
 107  * The payload must itself determine its own alignment from the biggest type it
 108  * contains.
 109  */
 110 static __inline__
 111 unsigned char record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
 112                                  struct channel *chan, size_t offset,
 113                                  size_t *pre_header_padding,
 114                                  struct lttng_ust_lib_ring_buffer_ctx *ctx)
 115 {
 116         struct lttng_channel *lttng_chan = channel_get_private(chan);
 117         struct lttng_event *event = ctx->priv;
 118         size_t orig_offset = offset;
 119         size_t padding;
 120
 121         switch (lttng_chan->header_type) {
 122         case 1: /* compact */
 123                 padding = lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
 124                 offset += padding;
 125                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 126                         offset += sizeof(uint32_t);     /* id and timestamp */
 127                 } else {
 128                         /* Minimum space taken by LTTNG_COMPACT_EVENT_BITS id */
 129                         offset += (LTTNG_COMPACT_EVENT_BITS + CHAR_BIT - 1) / CHAR_BIT;
 130                         /* Align extended struct on largest member */
 131                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 132                         offset += sizeof(uint32_t);     /* id */
 133                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 134                         offset += sizeof(uint64_t);     /* timestamp */
 135                 }
 136                 break;
 137         case 2: /* large */
 138                 padding = lib_ring_buffer_align(offset, lttng_alignof(uint16_t));
 139                 offset += padding;
 140                 offset += sizeof(uint16_t);
 141                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 142                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
 143                         offset += sizeof(uint32_t);     /* timestamp */
 144                 } else {
 145                         /* Align extended struct on largest member */
 146                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 147                         offset += sizeof(uint32_t);     /* id */
 148                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 149                         offset += sizeof(uint64_t);     /* timestamp */
 150                 }
 151                 break;
 152         default:
 153                 padding = 0;
 154                 WARN_ON_ONCE(1);
 155         }
 156         offset += ctx_get_size(offset, event->ctx);
 157         offset += ctx_get_size(offset, lttng_chan->ctx);
 158
 159         *pre_header_padding = padding;
 160         return offset - orig_offset;
 161 }
 162
 163 #include "../libringbuffer/api.h"
 164 #include "lttng-rb-clients.h"
 165
 166 static
 167 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
 168                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 169                                  uint32_t event_id);
 170
 171 /*
 172  * lttng_write_event_header
 173  *
 174  * Writes the event header to the offset (already aligned on 32-bits).
 175  *
 176  * @config: ring buffer instance configuration
 177  * @ctx: reservation context
 178  * @event_id: event ID
 179  */
 180 static __inline__
 181 void lttng_write_event_header(const struct lttng_ust_lib_ring_buffer_config *config,
 182                             struct lttng_ust_lib_ring_buffer_ctx *ctx,
 183                             uint32_t event_id)
 184 {
 185         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 186         struct lttng_event *event = ctx->priv;
 187
 188         if (caa_unlikely(ctx->rflags))
 189                 goto slow_path;
 190
 191         switch (lttng_chan->header_type) {
 192         case 1: /* compact */
 193         {
 194                 uint32_t id_time = 0;
 195
 196                 bt_bitfield_write(&id_time, uint32_t,
 197                                 0,
 198                                 LTTNG_COMPACT_EVENT_BITS,
 199                                 event_id);
 200                 bt_bitfield_write(&id_time, uint32_t,
 201                                 LTTNG_COMPACT_EVENT_BITS,
 202                                 LTTNG_COMPACT_TSC_BITS,
 203                                 ctx->tsc);
 204                 lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 205                 break;
 206         }
 207         case 2: /* large */
 208         {
 209                 uint32_t timestamp = (uint32_t) ctx->tsc;
 210                 uint16_t id = event_id;
 211
 212                 lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 213                 lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 214                 lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 215                 break;
 216         }
 217         default:
 218                 WARN_ON_ONCE(1);
 219         }
 220
 221         ctx_record(ctx, lttng_chan, lttng_chan->ctx);
 222         ctx_record(ctx, lttng_chan, event->ctx);
 223         lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 224
 225         return;
 226
 227 slow_path:
 228         lttng_write_event_header_slow(config, ctx, event_id);
 229 }
 230
 231 static
 232 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
 233                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 234                                  uint32_t event_id)
 235 {
 236         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 237         struct lttng_event *event = ctx->priv;
 238
 239         switch (lttng_chan->header_type) {
 240         case 1: /* compact */
 241                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 242                         uint32_t id_time = 0;
 243
 244                         bt_bitfield_write(&id_time, uint32_t,
 245                                         0,
 246                                         LTTNG_COMPACT_EVENT_BITS,
 247                                         event_id);
 248                         bt_bitfield_write(&id_time, uint32_t,
 249                                         LTTNG_COMPACT_EVENT_BITS,
 250                                         LTTNG_COMPACT_TSC_BITS,
 251                                         ctx->tsc);
 252                         lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 253                 } else {
 254                         uint8_t id = 0;
 255                         uint64_t timestamp = ctx->tsc;
 256
 257                         bt_bitfield_write(&id, uint8_t,
 258                                         0,
 259                                         LTTNG_COMPACT_EVENT_BITS,
 260                                         31);
 261                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 262                         /* Align extended struct on largest member */
 263                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 264                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 265                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 266                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 267                 }
 268                 break;
 269         case 2: /* large */
 270         {
 271                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 272                         uint32_t timestamp = (uint32_t) ctx->tsc;
 273                         uint16_t id = event_id;
 274
 275                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 276                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 277                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 278                 } else {
 279                         uint16_t id = 65535;
 280                         uint64_t timestamp = ctx->tsc;
 281
 282                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 283                         /* Align extended struct on largest member */
 284                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 285                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 286                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 287                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 288                 }
 289                 break;
 290         }
 291         default:
 292                 WARN_ON_ONCE(1);
 293         }
 294         ctx_record(ctx, lttng_chan, lttng_chan->ctx);
 295         ctx_record(ctx, lttng_chan, event->ctx);
 296         lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 297 }
 298
 299 static const struct lttng_ust_lib_ring_buffer_config client_config;
 300
 301 static uint64_t client_ring_buffer_clock_read(struct channel *chan)
 302 {
 303         return lib_ring_buffer_clock_read(chan);
 304 }
 305
 306 static
 307 size_t client_record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
 308                                  struct channel *chan, size_t offset,
 309                                  size_t *pre_header_padding,
 310                                  struct lttng_ust_lib_ring_buffer_ctx *ctx)
 311 {
 312         return record_header_size(config, chan, offset,
 313                                   pre_header_padding, ctx);
 314 }
 315
 316 /**
 317  * client_packet_header_size - called on buffer-switch to a new sub-buffer
 318  *
 319  * Return header size without padding after the structure. Don't use packed
 320  * structure because gcc generates inefficient code on some architectures
 321  * (powerpc, mips..)
 322  */
 323 static size_t client_packet_header_size(void)
 324 {
 325         return offsetof(struct packet_header, ctx.header_end);
 326 }
 327
 328 static void client_buffer_begin(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 329                                 unsigned int subbuf_idx,
 330                                 struct lttng_ust_shm_handle *handle)
 331 {
 332         struct channel *chan = shmp(handle, buf->backend.chan);
 333         struct packet_header *header =
 334                 (struct packet_header *)
 335                         lib_ring_buffer_offset_address(&buf->backend,
 336                                 subbuf_idx * chan->backend.subbuf_size,
 337                                 handle);
 338         struct lttng_channel *lttng_chan = channel_get_private(chan);
 339
 340         header->magic = CTF_MAGIC_NUMBER;
 341         memcpy(header->uuid, lttng_chan->uuid, sizeof(lttng_chan->uuid));
 342         header->stream_id = lttng_chan->id;
 343         header->ctx.timestamp_begin = tsc;
 344         header->ctx.timestamp_end = 0;
 345         header->ctx.content_size = ~0ULL; /* for debugging */
 346         header->ctx.packet_size = ~0ULL;
 347         header->ctx.events_discarded = 0;
 348         header->ctx.cpu_id = buf->backend.cpu;
 349 }
 350
 351 /*
 352  * offset is assumed to never be 0 here : never deliver a completely empty
 353  * subbuffer. data_size is between 1 and subbuf_size.
 354  */
 355 static void client_buffer_end(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 356                               unsigned int subbuf_idx, unsigned long data_size,
 357                               struct lttng_ust_shm_handle *handle)
 358 {
 359         struct channel *chan = shmp(handle, buf->backend.chan);
 360         struct packet_header *header =
 361                 (struct packet_header *)
 362                         lib_ring_buffer_offset_address(&buf->backend,
 363                                 subbuf_idx * chan->backend.subbuf_size,
 364                                 handle);
 365         unsigned long records_lost = 0;
 366
 367         header->ctx.timestamp_end = tsc;
 368         header->ctx.content_size =
 369                 (uint64_t) data_size * CHAR_BIT;                /* in bits */
 370         header->ctx.packet_size =
 371                 (uint64_t) PAGE_ALIGN(data_size) * CHAR_BIT;    /* in bits */
 372
 373         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 374         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 375         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 376         header->ctx.events_discarded = records_lost;
 377 }
 378
 379 static int client_buffer_create(struct lttng_ust_lib_ring_buffer *buf, void *priv,
 380                                 int cpu, const char *name, struct lttng_ust_shm_handle *handle)
 381 {
 382         return 0;
 383 }
 384
 385 static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf, void *priv, int cpu, struct lttng_ust_shm_handle *handle)
 386 {
 387 }
 388
 389 static struct packet_header *client_packet_header(struct lttng_ust_lib_ring_buffer *buf,
 390                 struct lttng_ust_shm_handle *handle)
 391 {
 392         return lib_ring_buffer_read_offset_address(&buf->backend, 0, handle);
 393 }
 394
 395 static int client_timestamp_begin(struct lttng_ust_lib_ring_buffer *buf,
 396                 struct lttng_ust_shm_handle *handle,
 397                 uint64_t *timestamp_begin)
 398 {
 399         struct packet_header *header;
 400
 401         header = client_packet_header(buf, handle);
 402         *timestamp_begin = header->ctx.timestamp_begin;
 403         return 0;
 404 }
 405
 406 static int client_timestamp_end(struct lttng_ust_lib_ring_buffer *buf,
 407                 struct lttng_ust_shm_handle *handle,
 408                 uint64_t *timestamp_end)
 409 {
 410         struct packet_header *header;
 411
 412         header = client_packet_header(buf, handle);
 413         *timestamp_end = header->ctx.timestamp_end;
 414         return 0;
 415 }
 416
 417 static int client_events_discarded(struct lttng_ust_lib_ring_buffer *buf,
 418                 struct lttng_ust_shm_handle *handle,
 419                 uint64_t *events_discarded)
 420 {
 421         struct packet_header *header;
 422
 423         header = client_packet_header(buf, handle);
 424         *events_discarded = header->ctx.events_discarded;
 425         return 0;
 426 }
 427
 428 static int client_content_size(struct lttng_ust_lib_ring_buffer *buf,
 429                 struct lttng_ust_shm_handle *handle,
 430                 uint64_t *content_size)
 431 {
 432         struct packet_header *header;
 433
 434         header = client_packet_header(buf, handle);
 435         *content_size = header->ctx.content_size;
 436         return 0;
 437 }
 438
 439 static int client_packet_size(struct lttng_ust_lib_ring_buffer *buf,
 440                 struct lttng_ust_shm_handle *handle,
 441                 uint64_t *packet_size)
 442 {
 443         struct packet_header *header;
 444
 445         header = client_packet_header(buf, handle);
 446         *packet_size = header->ctx.packet_size;
 447         return 0;
 448 }
 449
 450 static int client_stream_id(struct lttng_ust_lib_ring_buffer *buf,
 451                 struct lttng_ust_shm_handle *handle,
 452                 uint64_t *stream_id)
 453 {
 454         struct packet_header *header;
 455
 456         header = client_packet_header(buf, handle);
 457         *stream_id = header->stream_id;
 458         return 0;
 459 }
 460
 461 static int client_current_timestamp(struct lttng_ust_lib_ring_buffer *buf,
 462                 struct lttng_ust_shm_handle *handle,
 463                 uint64_t *ts)
 464 {
 465         struct channel *chan;
 466
 467         chan = shmp(handle, handle->chan);
 468         *ts = client_ring_buffer_clock_read(chan);
 469
 470         return 0;
 471 }
 472
 473 static const
 474 struct lttng_ust_client_lib_ring_buffer_client_cb client_cb = {
 475         .parent = {
 476                 .ring_buffer_clock_read = client_ring_buffer_clock_read,
 477                 .record_header_size = client_record_header_size,
 478                 .subbuffer_header_size = client_packet_header_size,
 479                 .buffer_begin = client_buffer_begin,
 480                 .buffer_end = client_buffer_end,
 481                 .buffer_create = client_buffer_create,
 482                 .buffer_finalize = client_buffer_finalize,
 483         },
 484         .timestamp_begin = client_timestamp_begin,
 485         .timestamp_end = client_timestamp_end,
 486         .events_discarded = client_events_discarded,
 487         .content_size = client_content_size,
 488         .packet_size = client_packet_size,
 489         .stream_id = client_stream_id,
 490         .current_timestamp = client_current_timestamp,
 491 };
 492
 493 static const struct lttng_ust_lib_ring_buffer_config client_config = {
 494         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 495         .cb.record_header_size = client_record_header_size,
 496         .cb.subbuffer_header_size = client_packet_header_size,
 497         .cb.buffer_begin = client_buffer_begin,
 498         .cb.buffer_end = client_buffer_end,
 499         .cb.buffer_create = client_buffer_create,
 500         .cb.buffer_finalize = client_buffer_finalize,
 501
 502         .tsc_bits = LTTNG_COMPACT_TSC_BITS,
 503         .alloc = RING_BUFFER_ALLOC_PER_CPU,
 504         .sync = RING_BUFFER_SYNC_GLOBAL,
 505         .mode = RING_BUFFER_MODE_TEMPLATE,
 506         .backend = RING_BUFFER_PAGE,
 507         .output = RING_BUFFER_MMAP,
 508         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 509         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 510         .wakeup = LTTNG_CLIENT_WAKEUP,
 511         .client_type = LTTNG_CLIENT_TYPE,
 512
 513         .cb_ptr = &client_cb.parent,
 514 };
 515
 516 const struct lttng_ust_client_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_cb;
 517
 518 static
 519 struct lttng_channel *_channel_create(const char *name,
 520                                 void *buf_addr,
 521                                 size_t subbuf_size, size_t num_subbuf,
 522                                 unsigned int switch_timer_interval,
 523                                 unsigned int read_timer_interval,
 524                                 unsigned char *uuid,
 525                                 uint32_t chan_id)
 526 {
 527         struct lttng_channel chan_priv_init;
 528         struct lttng_ust_shm_handle *handle;
 529         struct lttng_channel *lttng_chan;
 530         void *priv;
 531
 532         memset(&chan_priv_init, 0, sizeof(chan_priv_init));
 533         memcpy(chan_priv_init.uuid, uuid, LTTNG_UST_UUID_LEN);
 534         chan_priv_init.id = chan_id;
 535         handle = channel_create(&client_config, name,
 536                         &priv, __alignof__(struct lttng_channel),
 537                         sizeof(struct lttng_channel),
 538                         &chan_priv_init,
 539                         buf_addr, subbuf_size, num_subbuf,
 540                         switch_timer_interval, read_timer_interval);
 541         if (!handle)
 542                 return NULL;
 543         lttng_chan = priv;
 544         lttng_chan->handle = handle;
 545         lttng_chan->chan = shmp(handle, handle->chan);
 546         return lttng_chan;
 547 }
 548
 549 static
 550 void lttng_channel_destroy(struct lttng_channel *chan)
 551 {
 552         channel_destroy(chan->chan, chan->handle, 1);
 553 }
 554
 555 static
 556 int lttng_event_reserve(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 557                       uint32_t event_id)
 558 {
 559         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 560         int ret, cpu;
 561
 562         cpu = lib_ring_buffer_get_cpu(&client_config);
 563         if (cpu < 0)
 564                 return -EPERM;
 565         ctx->cpu = cpu;
 566
 567         switch (lttng_chan->header_type) {
 568         case 1: /* compact */
 569                 if (event_id > 30)
 570                         ctx->rflags |= LTTNG_RFLAG_EXTENDED;
 571                 break;
 572         case 2: /* large */
 573                 if (event_id > 65534)
 574                         ctx->rflags |= LTTNG_RFLAG_EXTENDED;
 575                 break;
 576         default:
 577                 WARN_ON_ONCE(1);
 578         }
 579
 580         ret = lib_ring_buffer_reserve(&client_config, ctx);
 581         if (ret)
 582                 goto put;
 583         lttng_write_event_header(&client_config, ctx, event_id);
 584         return 0;
 585 put:
 586         lib_ring_buffer_put_cpu(&client_config);
 587         return ret;
 588 }
 589
 590 static
 591 void lttng_event_commit(struct lttng_ust_lib_ring_buffer_ctx *ctx)
 592 {
 593         lib_ring_buffer_commit(&client_config, ctx);
 594         lib_ring_buffer_put_cpu(&client_config);
 595 }
 596
 597 static
 598 void lttng_event_write(struct lttng_ust_lib_ring_buffer_ctx *ctx, const void *src,
 599                      size_t len)
 600 {
 601         lib_ring_buffer_write(&client_config, ctx, src, len);
 602 }
 603
 604 static
 605 void lttng_event_strcpy(struct lttng_ust_lib_ring_buffer_ctx *ctx, const char *src,
 606                      size_t len)
 607 {
 608         lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
 609 }
 610
 611 #if 0
 612 static
 613 wait_queue_head_t *lttng_get_reader_wait_queue(struct channel *chan)
 614 {
 615         return &chan->read_wait;
 616 }
 617
 618 static
 619 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 620 {
 621         return &chan->hp_wait;
 622 }
 623 #endif //0
 624
 625 static
 626 int lttng_is_finalized(struct channel *chan)
 627 {
 628         return lib_ring_buffer_channel_is_finalized(chan);
 629 }
 630
 631 static
 632 int lttng_is_disabled(struct channel *chan)
 633 {
 634         return lib_ring_buffer_channel_is_disabled(chan);
 635 }
 636
 637 static
 638 int lttng_flush_buffer(struct channel *chan, struct lttng_ust_shm_handle *handle)
 639 {
 640         struct lttng_ust_lib_ring_buffer *buf;
 641         int cpu;
 642
 643         for_each_channel_cpu(cpu, chan) {
 644                 int shm_fd, wait_fd, wakeup_fd;
 645                 uint64_t memory_map_size;
 646
 647                 buf = channel_get_ring_buffer(&client_config, chan,
 648                                 cpu, handle, &shm_fd, &wait_fd,
 649                                 &wakeup_fd, &memory_map_size);
 650                 lib_ring_buffer_switch(&client_config, buf,
 651                                 SWITCH_ACTIVE, handle);
 652         }
 653         return 0;
 654 }
 655
 656 static struct lttng_transport lttng_relay_transport = {
 657         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 658         .ops = {
 659                 .channel_create = _channel_create,
 660                 .channel_destroy = lttng_channel_destroy,
 661                 .u.has_strcpy = 1,
 662                 .event_reserve = lttng_event_reserve,
 663                 .event_commit = lttng_event_commit,
 664                 .event_write = lttng_event_write,
 665                 .packet_avail_size = NULL,      /* Would be racy anyway */
 666                 //.get_reader_wait_queue = lttng_get_reader_wait_queue,
 667                 //.get_hp_wait_queue = lttng_get_hp_wait_queue,
 668                 .is_finalized = lttng_is_finalized,
 669                 .is_disabled = lttng_is_disabled,
 670                 .flush_buffer = lttng_flush_buffer,
 671                 .event_strcpy = lttng_event_strcpy,
 672         },
 673         .client_config = &client_config,
 674 };
 675
 676 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 677 {
 678         DBG("LTT : ltt ring buffer client \"%s\" init\n",
 679                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 680         lttng_transport_register(&lttng_relay_transport);
 681 }
 682
 683 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 684 {
 685         DBG("LTT : ltt ring buffer client \"%s\" exit\n",
 686                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 687         lttng_transport_unregister(&lttng_relay_transport);
 688 }