libust/tracer.h

   1 /*
   2  * Copyright (C) 2005,2006,2008 Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
   3  * Copyright (C) 2009 Pierre-Marc Fournier
   4  *
   5  * This contains the definitions for the Linux Trace Toolkit tracer.
   6  *
   7  * Ported to userspace by Pierre-Marc Fournier.
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  22  */
  23
  24 #ifndef _LTT_TRACER_H
  25 #define _LTT_TRACER_H
  26
  27 #include <sys/types.h>
  28 #include <stdarg.h>
  29 //#include "list.h"
  30 #include <ust/kernelcompat.h>
  31 #include "buffers.h"
  32 #include "channels.h"
  33 #include "tracercore.h"
  34 #include <ust/marker.h>
  35 #include <ust/probe.h>
  36
  37 /* Number of bytes to log with a read/write event */
  38 #define LTT_LOG_RW_SIZE                 32L
  39
  40 /* Interval (in jiffies) at which the LTT per-CPU timer fires */
  41 #define LTT_PERCPU_TIMER_INTERVAL       1
  42
  43 #ifndef LTT_ARCH_TYPE
  44 #define LTT_ARCH_TYPE                   LTT_ARCH_TYPE_UNDEFINED
  45 #endif
  46
  47 #ifndef LTT_ARCH_VARIANT
  48 #define LTT_ARCH_VARIANT                LTT_ARCH_VARIANT_NONE
  49 #endif
  50
  51 struct ltt_active_marker;
  52
  53 /* Maximum number of callbacks per marker */
  54 #define LTT_NR_CALLBACKS        10
  55
  56 struct ltt_serialize_closure;
  57 struct ltt_probe_private_data;
  58
  59 struct ltt_serialize_closure {
  60         ltt_serialize_cb *callbacks;
  61         long cb_args[LTT_NR_CALLBACKS];
  62         unsigned int cb_idx;
  63 };
  64
  65 extern size_t ltt_serialize_data(struct ust_buffer *buf, size_t buf_offset,
  66                         struct ltt_serialize_closure *closure,
  67                         void *serialize_private,
  68                         int *largest_align, const char *fmt, va_list *args);
  69
  70 struct ltt_probe_private_data {
  71         struct ltt_trace_struct *trace; /*
  72                                          * Target trace, for metadata
  73                                          * or statedump.
  74                                          */
  75         ltt_serialize_cb serializer;    /*
  76                                          * Serialization function override.
  77                                          */
  78         void *serialize_private;        /*
  79                                          * Private data for serialization
  80                                          * functions.
  81                                          */
  82 };
  83
  84 enum ltt_channels {
  85         LTT_CHANNEL_METADATA,
  86         LTT_CHANNEL_UST,
  87 };
  88
  89 struct ltt_active_marker {
  90         struct list_head node;          /* active markers list */
  91         const char *channel;
  92         const char *name;
  93         const char *format;
  94         struct ltt_available_probe *probe;
  95 };
  96
  97 struct marker; //ust//
  98 extern void ltt_vtrace(const struct marker *mdata, void *probe_data,
  99         struct registers *regs, void *call_data, const char *fmt, va_list *args);
 100 extern void ltt_trace(const struct marker *mdata, void *probe_data,
 101         struct registers *regs, void *call_data, const char *fmt, ...);
 102
 103 /*
 104  * Unique ID assigned to each registered probe.
 105  */
 106 enum marker_id {
 107         MARKER_ID_SET_MARKER_ID = 0,    /* Static IDs available (range 0-7) */
 108         MARKER_ID_SET_MARKER_FORMAT,
 109         MARKER_ID_COMPACT,              /* Compact IDs (range: 8-127)       */
 110         MARKER_ID_DYNAMIC,              /* Dynamic IDs (range: 128-65535)   */
 111 };
 112
 113 /* static ids 0-1 reserved for internal use. */
 114 #define MARKER_CORE_IDS         2
 115 static inline enum marker_id marker_id_type(uint16_t id)
 116 {
 117         if (id < MARKER_CORE_IDS)
 118                 return (enum marker_id)id;
 119         else
 120                 return MARKER_ID_DYNAMIC;
 121 }
 122
 123 struct user_dbg_data {
 124         unsigned long avail_size;
 125         unsigned long write;
 126         unsigned long read;
 127 };
 128
 129 struct ltt_trace_ops {
 130         /* First 32 bytes cache-hot cacheline */
 131         int (*reserve_slot) (struct ltt_trace_struct *trace,
 132                                 struct ust_channel *channel,
 133                                 void **transport_data, size_t data_size,
 134                                 size_t *slot_size, long *buf_offset, u64 *tsc,
 135                                 unsigned int *rflags,
 136                                 int largest_align);
 137 //ust// void (*commit_slot) (struct ltt_channel_struct *channel,
 138 //ust//                         void **transport_data, long buf_offset,
 139 //ust//                         size_t slot_size);
 140         void (*wakeup_channel) (struct ust_channel *channel);
 141         int (*user_blocking) (struct ltt_trace_struct *trace,
 142                                 unsigned int index, size_t data_size,
 143                                 struct user_dbg_data *dbg);
 144         /* End of first 32 bytes cacheline */
 145         int (*create_dirs) (struct ltt_trace_struct *new_trace);
 146         void (*remove_dirs) (struct ltt_trace_struct *new_trace);
 147         int (*create_channel) (const char *trace_name,
 148                                 struct ltt_trace_struct *trace,
 149                                 const char *channel_name,
 150                                 struct ust_channel *channel,
 151                                 unsigned int subbuf_size,
 152                                 unsigned int n_subbufs, int overwrite);
 153         void (*finish_channel) (struct ust_channel *channel);
 154         void (*remove_channel) (struct ust_channel *channel);
 155         void (*user_errors) (struct ltt_trace_struct *trace,
 156                                 unsigned int index, size_t data_size,
 157                                 struct user_dbg_data *dbg);
 158 } ____cacheline_aligned;
 159
 160 struct ltt_transport {
 161         char *name;
 162         struct module *owner;
 163         struct list_head node;
 164         struct ltt_trace_ops ops;
 165 };
 166
 167 enum trace_mode { LTT_TRACE_NORMAL, LTT_TRACE_FLIGHT, LTT_TRACE_HYBRID };
 168
 169 #define CHANNEL_FLAG_ENABLE     (1U<<0)
 170 #define CHANNEL_FLAG_OVERWRITE  (1U<<1)
 171
 172 /* Per-trace information - each trace/flight recorder represented by one */
 173 struct ltt_trace_struct {
 174         /* First 32 bytes cache-hot cacheline */
 175         struct list_head list;
 176         struct ltt_trace_ops *ops;
 177         int active;
 178         /* Second 32 bytes cache-hot cacheline */
 179         struct ust_channel *channels;
 180         unsigned int nr_channels;
 181         u32 freq_scale;
 182         u64 start_freq;
 183         u64 start_tsc;
 184         unsigned long long start_monotonic;
 185         struct timeval          start_time;
 186         struct ltt_channel_setting *settings;
 187         struct {
 188                 struct dentry                   *trace_root;
 189         } dentry;
 190         struct kref kref; /* Each channel has a kref of the trace struct */
 191         struct ltt_transport *transport;
 192         struct kref ltt_transport_kref;
 193         char trace_name[NAME_MAX];
 194 } ____cacheline_aligned;
 195
 196 /* Hardcoded event headers
 197  *
 198  * event header for a trace with active heartbeat : 27 bits timestamps
 199  *
 200  * headers are 32-bits aligned. In order to insure such alignment, a dynamic per
 201  * trace alignment value must be done.
 202  *
 203  * Remember that the C compiler does align each member on the boundary
 204  * equivalent to their own size.
 205  *
 206  * As relay subbuffers are aligned on pages, we are sure that they are 4 and 8
 207  * bytes aligned, so the buffer header and trace header are aligned.
 208  *
 209  * Event headers are aligned depending on the trace alignment option.
 210  *
 211  * Note using C structure bitfields for cross-endianness and portability
 212  * concerns.
 213  */
 214
 215 #define LTT_RESERVED_EVENTS     3
 216 #define LTT_EVENT_BITS          5
 217 #define LTT_FREE_EVENTS         ((1 << LTT_EVENT_BITS) - LTT_RESERVED_EVENTS)
 218 #define LTT_TSC_BITS            27
 219 #define LTT_TSC_MASK            ((1 << LTT_TSC_BITS) - 1)
 220
 221 struct ltt_event_header {
 222         u32 id_time;            /* 5 bits event id (MSB); 27 bits time (LSB) */
 223 };
 224
 225 /* Reservation flags */
 226 #define LTT_RFLAG_ID                    (1 << 0)
 227 #define LTT_RFLAG_ID_SIZE               (1 << 1)
 228 #define LTT_RFLAG_ID_SIZE_TSC           (1 << 2)
 229
 230 /*
 231  * We use asm/timex.h : cpu_khz/HZ variable in here : we might have to deal
 232  * specifically with CPU frequency scaling someday, so using an interpolation
 233  * between the start and end of buffer values is not flexible enough. Using an
 234  * immediate frequency value permits to calculate directly the times for parts
 235  * of a buffer that would be before a frequency change.
 236  *
 237  * Keep the natural field alignment for _each field_ within this structure if
 238  * you ever add/remove a field from this header. Packed attribute is not used
 239  * because gcc generates poor code on at least powerpc and mips. Don't ever
 240  * let gcc add padding between the structure elements.
 241  */
 242 struct ltt_subbuffer_header {
 243         uint64_t cycle_count_begin;     /* Cycle count at subbuffer start */
 244         uint64_t cycle_count_end;       /* Cycle count at subbuffer end */
 245         uint32_t magic_number;          /*
 246                                          * Trace magic number.
 247                                          * contains endianness information.
 248                                          */
 249         uint8_t major_version;
 250         uint8_t minor_version;
 251         uint8_t arch_size;              /* Architecture pointer size */
 252         uint8_t alignment;              /* LTT data alignment */
 253         uint64_t start_time_sec;        /* NTP-corrected start time */
 254         uint64_t start_time_usec;
 255         uint64_t start_freq;            /*
 256                                          * Frequency at trace start,
 257                                          * used all along the trace.
 258                                          */
 259         uint32_t freq_scale;            /* Frequency scaling (divisor) */
 260         uint32_t lost_size;             /* Size unused at end of subbuffer */
 261         uint32_t buf_size;              /* Size of this subbuffer */
 262         uint32_t events_lost;           /*
 263                                          * Events lost in this subbuffer since
 264                                          * the beginning of the trace.
 265                                          * (may overflow)
 266                                          */
 267         uint32_t subbuf_corrupt;        /*
 268                                          * Corrupted (lost) subbuffers since
 269                                          * the begginig of the trace.
 270                                          * (may overflow)
 271                                          */
 272         uint8_t header_end[0];          /* End of header */
 273 };
 274
 275 /**
 276  * ltt_subbuffer_header_size - called on buffer-switch to a new sub-buffer
 277  *
 278  * Return header size without padding after the structure. Don't use packed
 279  * structure because gcc generates inefficient code on some architectures
 280  * (powerpc, mips..)
 281  */
 282 static inline size_t ltt_subbuffer_header_size(void)
 283 {
 284         return offsetof(struct ltt_subbuffer_header, header_end);
 285 }
 286
 287 /*
 288  * ust_get_header_size
 289  *
 290  * Calculate alignment offset to 32-bits. This is the alignment offset of the
 291  * event header.
 292  *
 293  * Important note :
 294  * The event header must be 32-bits. The total offset calculated here :
 295  *
 296  * Alignment of header struct on 32 bits (min arch size, header size)
 297  * + sizeof(header struct)  (32-bits)
 298  * + (opt) u16 (ext. event id)
 299  * + (opt) u16 (event_size) (if event_size == 0xFFFFUL, has ext. event size)
 300  * + (opt) u32 (ext. event size)
 301  * + (opt) u64 full TSC (aligned on min(64-bits, arch size))
 302  *
 303  * The payload must itself determine its own alignment from the biggest type it
 304  * contains.
 305  * */
 306 static inline unsigned char ust_get_header_size(
 307                 struct ust_channel *channel,
 308                 size_t offset,
 309                 size_t data_size,
 310                 size_t *before_hdr_pad,
 311                 unsigned int rflags)
 312 {
 313         size_t orig_offset = offset;
 314         size_t padding;
 315
 316         padding = ltt_align(offset, sizeof(struct ltt_event_header));
 317         offset += padding;
 318         offset += sizeof(struct ltt_event_header);
 319
 320         switch (rflags) {
 321         case LTT_RFLAG_ID_SIZE_TSC:
 322                 offset += sizeof(u16) + sizeof(u16);
 323                 if (data_size >= 0xFFFFU)
 324                         offset += sizeof(u32);
 325                 offset += ltt_align(offset, sizeof(u64));
 326                 offset += sizeof(u64);
 327                 break;
 328         case LTT_RFLAG_ID_SIZE:
 329                 offset += sizeof(u16) + sizeof(u16);
 330                 if (data_size >= 0xFFFFU)
 331                         offset += sizeof(u32);
 332                 break;
 333         case LTT_RFLAG_ID:
 334                 offset += sizeof(u16);
 335                 break;
 336         }
 337
 338         *before_hdr_pad = padding;
 339         return offset - orig_offset;
 340 }
 341
 342 /*
 343  * ltt_write_event_header
 344  *
 345  * Writes the event header to the offset (already aligned on 32-bits).
 346  *
 347  * @trace : trace to write to.
 348  * @channel : pointer to the channel structure..
 349  * @buf : buffer to write to.
 350  * @buf_offset : buffer offset to write to (aligned on 32 bits).
 351  * @eID : event ID
 352  * @event_size : size of the event, excluding the event header.
 353  * @tsc : time stamp counter.
 354  * @rflags : reservation flags.
 355  *
 356  * returns : offset where the event data must be written.
 357  */
 358 static inline size_t ltt_write_event_header(struct ltt_trace_struct *trace,
 359                 struct ust_buffer *buf, long buf_offset,
 360                 u16 eID, size_t event_size,
 361                 u64 tsc, unsigned int rflags)
 362 {
 363         struct ltt_event_header header;
 364         size_t small_size;
 365
 366         switch (rflags) {
 367         case LTT_RFLAG_ID_SIZE_TSC:
 368                 header.id_time = 29 << LTT_TSC_BITS;
 369                 break;
 370         case LTT_RFLAG_ID_SIZE:
 371                 header.id_time = 30 << LTT_TSC_BITS;
 372                 break;
 373         case LTT_RFLAG_ID:
 374                 header.id_time = 31 << LTT_TSC_BITS;
 375                 break;
 376         default:
 377                 header.id_time = eID << LTT_TSC_BITS;
 378                 break;
 379         }
 380         header.id_time |= (u32)tsc & LTT_TSC_MASK;
 381         ust_buffers_write(buf, buf_offset, &header, sizeof(header));
 382         buf_offset += sizeof(header);
 383
 384         switch (rflags) {
 385         case LTT_RFLAG_ID_SIZE_TSC:
 386                 small_size = min_t(size_t, event_size, 0xFFFFU);
 387                 ust_buffers_write(buf, buf_offset,
 388                         (u16[]){ (u16)eID }, sizeof(u16));
 389                 buf_offset += sizeof(u16);
 390                 ust_buffers_write(buf, buf_offset,
 391                         (u16[]){ (u16)small_size }, sizeof(u16));
 392                 buf_offset += sizeof(u16);
 393                 if (small_size == 0xFFFFU) {
 394                         ust_buffers_write(buf, buf_offset,
 395                                 (u32[]){ (u32)event_size }, sizeof(u32));
 396                         buf_offset += sizeof(u32);
 397                 }
 398                 buf_offset += ltt_align(buf_offset, sizeof(u64));
 399                 ust_buffers_write(buf, buf_offset,
 400                         (u64[]){ (u64)tsc }, sizeof(u64));
 401                 buf_offset += sizeof(u64);
 402                 break;
 403         case LTT_RFLAG_ID_SIZE:
 404                 small_size = min_t(size_t, event_size, 0xFFFFU);
 405                 ust_buffers_write(buf, buf_offset,
 406                         (u16[]){ (u16)eID }, sizeof(u16));
 407                 buf_offset += sizeof(u16);
 408                 ust_buffers_write(buf, buf_offset,
 409                         (u16[]){ (u16)small_size }, sizeof(u16));
 410                 buf_offset += sizeof(u16);
 411                 if (small_size == 0xFFFFU) {
 412                         ust_buffers_write(buf, buf_offset,
 413                                 (u32[]){ (u32)event_size }, sizeof(u32));
 414                         buf_offset += sizeof(u32);
 415                 }
 416                 break;
 417         case LTT_RFLAG_ID:
 418                 ust_buffers_write(buf, buf_offset,
 419                         (u16[]){ (u16)eID }, sizeof(u16));
 420                 buf_offset += sizeof(u16);
 421                 break;
 422         default:
 423                 break;
 424         }
 425
 426         return buf_offset;
 427 }
 428
 429 /* Lockless LTTng */
 430
 431 /*
 432  * ltt_reserve_slot
 433  *
 434  * Atomic slot reservation in a LTTng buffer. It will take care of
 435  * sub-buffer switching.
 436  *
 437  * Parameters:
 438  *
 439  * @trace : the trace structure to log to.
 440  * @channel : the chanel to reserve space into.
 441  * @transport_data : specific transport data.
 442  * @data_size : size of the variable length data to log.
 443  * @slot_size : pointer to total size of the slot (out)
 444  * @buf_offset : pointer to reserve offset (out)
 445  * @tsc : pointer to the tsc at the slot reservation (out)
 446  * @rflags : reservation flags (header specificity)
 447  * @cpu : cpu id
 448  *
 449  * Return : -ENOSPC if not enough space, else 0.
 450  */
 451 static inline int ltt_reserve_slot(
 452                 struct ltt_trace_struct *trace,
 453                 struct ust_channel *channel,
 454                 void **transport_data,
 455                 size_t data_size,
 456                 size_t *slot_size,
 457                 long *buf_offset,
 458                 u64 *tsc,
 459                 unsigned int *rflags,
 460                 int largest_align)
 461 {
 462         return trace->ops->reserve_slot(trace, channel, transport_data,
 463                         data_size, slot_size, buf_offset, tsc, rflags,
 464                         largest_align);
 465 }
 466
 467
 468 ///*
 469 // * ltt_commit_slot
 470 // *
 471 // * Atomic unordered slot commit. Increments the commit count in the
 472 // * specified sub-buffer, and delivers it if necessary.
 473 // *
 474 // * Parameters:
 475 // *
 476 // * @channel : the chanel to reserve space into.
 477 // * @transport_data : specific transport data.
 478 // * @buf_offset : offset of beginning of reserved slot
 479 // * @slot_size : size of the reserved slot.
 480 // */
 481 //static inline void ltt_commit_slot(
 482 //              struct ltt_channel_struct *channel,
 483 //              void **transport_data,
 484 //              long buf_offset,
 485 //              size_t slot_size)
 486 //{
 487 //      struct ltt_trace_struct *trace = channel->trace;
 488 //
 489 //      trace->ops->commit_slot(channel, transport_data, buf_offset, slot_size);
 490 //}
 491
 492 /*
 493  * Control channels :
 494  * control/metadata
 495  * control/interrupts
 496  * control/...
 497  *
 498  * cpu channel :
 499  * cpu
 500  */
 501
 502 #define LTT_METADATA_CHANNEL            "metadata_state"
 503 #define LTT_UST_CHANNEL                 "ust"
 504
 505 #define LTT_FLIGHT_PREFIX       "flight-"
 506
 507 /* Tracer properties */
 508 //#define LTT_DEFAULT_SUBBUF_SIZE_LOW   134217728
 509 #define LTT_DEFAULT_SUBBUF_SIZE_LOW     65536
 510 //#define LTT_DEFAULT_SUBBUF_SIZE_LOW   4096
 511 #define LTT_DEFAULT_N_SUBBUFS_LOW       2
 512 //#define LTT_DEFAULT_SUBBUF_SIZE_MED   134217728
 513 #define LTT_DEFAULT_SUBBUF_SIZE_MED     262144
 514 //#define LTT_DEFAULT_SUBBUF_SIZE_MED   4096
 515 #define LTT_DEFAULT_N_SUBBUFS_MED       2
 516 //#define LTT_DEFAULT_SUBBUF_SIZE_HIGH  134217728
 517 #define LTT_DEFAULT_SUBBUF_SIZE_HIGH    1048576
 518 //#define LTT_DEFAULT_SUBBUF_SIZE_HIGH  4096
 519 #define LTT_DEFAULT_N_SUBBUFS_HIGH      2
 520 #define LTT_TRACER_MAGIC_NUMBER         0x00D6B7ED
 521 #define LTT_TRACER_VERSION_MAJOR        2
 522 #define LTT_TRACER_VERSION_MINOR        3
 523
 524 /*
 525  * Size reserved for high priority events (interrupts, NMI, BH) at the end of a
 526  * nearly full buffer. User space won't use this last amount of space when in
 527  * blocking mode. This space also includes the event header that would be
 528  * written by this user space event.
 529  */
 530 #define LTT_RESERVE_CRITICAL            4096
 531
 532 /* Register and unregister function pointers */
 533
 534 enum ltt_module_function {
 535         LTT_FUNCTION_RUN_FILTER,
 536         LTT_FUNCTION_FILTER_CONTROL,
 537         LTT_FUNCTION_STATEDUMP
 538 };
 539
 540 extern void ltt_transport_register(struct ltt_transport *transport);
 541 extern void ltt_transport_unregister(struct ltt_transport *transport);
 542
 543 /* Exported control function */
 544
 545 union ltt_control_args {
 546         struct {
 547                 enum trace_mode mode;
 548                 unsigned int subbuf_size_low;
 549                 unsigned int n_subbufs_low;
 550                 unsigned int subbuf_size_med;
 551                 unsigned int n_subbufs_med;
 552                 unsigned int subbuf_size_high;
 553                 unsigned int n_subbufs_high;
 554         } new_trace;
 555 };
 556
 557 extern int _ltt_trace_setup(const char *trace_name);
 558 extern int ltt_trace_setup(const char *trace_name);
 559 extern struct ltt_trace_struct *_ltt_trace_find_setup(const char *trace_name);
 560 extern int ltt_trace_set_type(const char *trace_name, const char *trace_type);
 561 extern int ltt_trace_set_channel_subbufsize(const char *trace_name,
 562                 const char *channel_name, unsigned int size);
 563 extern int ltt_trace_set_channel_subbufcount(const char *trace_name,
 564                 const char *channel_name, unsigned int cnt);
 565 extern int ltt_trace_set_channel_enable(const char *trace_name,
 566                 const char *channel_name, unsigned int enable);
 567 extern int ltt_trace_set_channel_overwrite(const char *trace_name,
 568                 const char *channel_name, unsigned int overwrite);
 569 extern int ltt_trace_alloc(const char *trace_name);
 570 extern int ltt_trace_destroy(const char *trace_name);
 571 extern int ltt_trace_start(const char *trace_name);
 572 extern int ltt_trace_stop(const char *trace_name);
 573
 574 enum ltt_filter_control_msg {
 575         LTT_FILTER_DEFAULT_ACCEPT,
 576         LTT_FILTER_DEFAULT_REJECT
 577 };
 578
 579 extern int ltt_filter_control(enum ltt_filter_control_msg msg,
 580                 const char *trace_name);
 581
 582 extern struct dentry *get_filter_root(void);
 583
 584 extern void ltt_write_trace_header(struct ltt_trace_struct *trace,
 585                 struct ltt_subbuffer_header *header);
 586 extern void ltt_buffer_destroy(struct ust_channel *ltt_chan);
 587
 588 extern void ltt_core_register(int (*function)(u8, void *));
 589
 590 extern void ltt_core_unregister(void);
 591
 592 extern void ltt_release_trace(struct kref *kref);
 593 extern void ltt_release_transport(struct kref *kref);
 594
 595 extern void ltt_dump_marker_state(struct ltt_trace_struct *trace);
 596
 597 extern void ltt_lock_traces(void);
 598 extern void ltt_unlock_traces(void);
 599
 600 extern struct ltt_trace_struct *_ltt_trace_find(const char *trace_name);
 601
 602 #endif /* _LTT_TRACER_H */