kernel/trace/trace_sched_wakeup.c

   1 /*
   2  * trace task wakeup timings
   3  *
   4  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
   5  * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
   6  *
   7  * Based on code from the latency_tracer, that is:
   8  *
   9  *  Copyright (C) 2004-2006 Ingo Molnar
  10  *  Copyright (C) 2004 Nadia Yvette Chambers
  11  */
  12 #include <linux/module.h>
  13 #include <linux/fs.h>
  14 #include <linux/debugfs.h>
  15 #include <linux/kallsyms.h>
  16 #include <linux/uaccess.h>
  17 #include <linux/ftrace.h>
  18 #include <linux/sched/rt.h>
  19 #include <linux/sched/deadline.h>
  20 #include <trace/events/sched.h>
  21 #include "trace.h"
  22
  23 static struct trace_array       *wakeup_trace;
  24 static int __read_mostly        tracer_enabled;
  25
  26 static struct task_struct       *wakeup_task;
  27 static int                      wakeup_cpu;
  28 static int                      wakeup_current_cpu;
  29 static unsigned                 wakeup_prio = -1;
  30 static int                      wakeup_rt;
  31 static int                      wakeup_dl;
  32 static int                      tracing_dl = 0;
  33
  34 static arch_spinlock_t wakeup_lock =
  35         (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
  36
  37 static void wakeup_reset(struct trace_array *tr);
  38 static void __wakeup_reset(struct trace_array *tr);
  39 static int wakeup_graph_entry(struct ftrace_graph_ent *trace);
  40 static void wakeup_graph_return(struct ftrace_graph_ret *trace);
  41
  42 static int save_flags;
  43 static bool function_enabled;
  44
  45 #define TRACE_DISPLAY_GRAPH     1
  46
  47 static struct tracer_opt trace_opts[] = {
  48 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  49         /* display latency trace as call graph */
  50         { TRACER_OPT(display-graph, TRACE_DISPLAY_GRAPH) },
  51 #endif
  52         { } /* Empty entry */
  53 };
  54
  55 static struct tracer_flags tracer_flags = {
  56         .val  = 0,
  57         .opts = trace_opts,
  58 };
  59
  60 #define is_graph() (tracer_flags.val & TRACE_DISPLAY_GRAPH)
  61
  62 #ifdef CONFIG_FUNCTION_TRACER
  63
  64 /*
  65  * Prologue for the wakeup function tracers.
  66  *
  67  * Returns 1 if it is OK to continue, and preemption
  68  *            is disabled and data->disabled is incremented.
  69  *         0 if the trace is to be ignored, and preemption
  70  *            is not disabled and data->disabled is
  71  *            kept the same.
  72  *
  73  * Note, this function is also used outside this ifdef but
  74  *  inside the #ifdef of the function graph tracer below.
  75  *  This is OK, since the function graph tracer is
  76  *  dependent on the function tracer.
  77  */
  78 static int
  79 func_prolog_preempt_disable(struct trace_array *tr,
  80                             struct trace_array_cpu **data,
  81                             int *pc)
  82 {
  83         long disabled;
  84         int cpu;
  85
  86         if (likely(!wakeup_task))
  87                 return 0;
  88
  89         *pc = preempt_count();
  90         preempt_disable_notrace();
  91
  92         cpu = raw_smp_processor_id();
  93         if (cpu != wakeup_current_cpu)
  94                 goto out_enable;
  95
  96         *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
  97         disabled = atomic_inc_return(&(*data)->disabled);
  98         if (unlikely(disabled != 1))
  99                 goto out;
 100
 101         return 1;
 102
 103 out:
 104         atomic_dec(&(*data)->disabled);
 105
 106 out_enable:
 107         preempt_enable_notrace();
 108         return 0;
 109 }
 110
 111 /*
 112  * wakeup uses its own tracer function to keep the overhead down:
 113  */
 114 static void
 115 wakeup_tracer_call(unsigned long ip, unsigned long parent_ip,
 116                    struct ftrace_ops *op, struct pt_regs *pt_regs)
 117 {
 118         struct trace_array *tr = wakeup_trace;
 119         struct trace_array_cpu *data;
 120         unsigned long flags;
 121         int pc;
 122
 123         if (!func_prolog_preempt_disable(tr, &data, &pc))
 124                 return;
 125
 126         local_irq_save(flags);
 127         trace_function(tr, ip, parent_ip, flags, pc);
 128         local_irq_restore(flags);
 129
 130         atomic_dec(&data->disabled);
 131         preempt_enable_notrace();
 132 }
 133
 134 static struct ftrace_ops trace_ops __read_mostly =
 135 {
 136         .func = wakeup_tracer_call,
 137         .flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE,
 138 };
 139 #endif /* CONFIG_FUNCTION_TRACER */
 140
 141 static int register_wakeup_function(int graph, int set)
 142 {
 143         int ret;
 144
 145         /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
 146         if (function_enabled || (!set && !(trace_flags & TRACE_ITER_FUNCTION)))
 147                 return 0;
 148
 149         if (graph)
 150                 ret = register_ftrace_graph(&wakeup_graph_return,
 151                                             &wakeup_graph_entry);
 152         else
 153                 ret = register_ftrace_function(&trace_ops);
 154
 155         if (!ret)
 156                 function_enabled = true;
 157
 158         return ret;
 159 }
 160
 161 static void unregister_wakeup_function(int graph)
 162 {
 163         if (!function_enabled)
 164                 return;
 165
 166         if (graph)
 167                 unregister_ftrace_graph();
 168         else
 169                 unregister_ftrace_function(&trace_ops);
 170
 171         function_enabled = false;
 172 }
 173
 174 static void wakeup_function_set(int set)
 175 {
 176         if (set)
 177                 register_wakeup_function(is_graph(), 1);
 178         else
 179                 unregister_wakeup_function(is_graph());
 180 }
 181
 182 static int wakeup_flag_changed(struct tracer *tracer, u32 mask, int set)
 183 {
 184         if (mask & TRACE_ITER_FUNCTION)
 185                 wakeup_function_set(set);
 186
 187         return trace_keep_overwrite(tracer, mask, set);
 188 }
 189
 190 static int start_func_tracer(int graph)
 191 {
 192         int ret;
 193
 194         ret = register_wakeup_function(graph, 0);
 195
 196         if (!ret && tracing_is_enabled())
 197                 tracer_enabled = 1;
 198         else
 199                 tracer_enabled = 0;
 200
 201         return ret;
 202 }
 203
 204 static void stop_func_tracer(int graph)
 205 {
 206         tracer_enabled = 0;
 207
 208         unregister_wakeup_function(graph);
 209 }
 210
 211 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 212 static int wakeup_set_flag(u32 old_flags, u32 bit, int set)
 213 {
 214
 215         if (!(bit & TRACE_DISPLAY_GRAPH))
 216                 return -EINVAL;
 217
 218         if (!(is_graph() ^ set))
 219                 return 0;
 220
 221         stop_func_tracer(!set);
 222
 223         wakeup_reset(wakeup_trace);
 224         tracing_max_latency = 0;
 225
 226         return start_func_tracer(set);
 227 }
 228
 229 static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
 230 {
 231         struct trace_array *tr = wakeup_trace;
 232         struct trace_array_cpu *data;
 233         unsigned long flags;
 234         int pc, ret = 0;
 235
 236         if (!func_prolog_preempt_disable(tr, &data, &pc))
 237                 return 0;
 238
 239         local_save_flags(flags);
 240         ret = __trace_graph_entry(tr, trace, flags, pc);
 241         atomic_dec(&data->disabled);
 242         preempt_enable_notrace();
 243
 244         return ret;
 245 }
 246
 247 static void wakeup_graph_return(struct ftrace_graph_ret *trace)
 248 {
 249         struct trace_array *tr = wakeup_trace;
 250         struct trace_array_cpu *data;
 251         unsigned long flags;
 252         int pc;
 253
 254         if (!func_prolog_preempt_disable(tr, &data, &pc))
 255                 return;
 256
 257         local_save_flags(flags);
 258         __trace_graph_return(tr, trace, flags, pc);
 259         atomic_dec(&data->disabled);
 260
 261         preempt_enable_notrace();
 262         return;
 263 }
 264
 265 static void wakeup_trace_open(struct trace_iterator *iter)
 266 {
 267         if (is_graph())
 268                 graph_trace_open(iter);
 269 }
 270
 271 static void wakeup_trace_close(struct trace_iterator *iter)
 272 {
 273         if (iter->private)
 274                 graph_trace_close(iter);
 275 }
 276
 277 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_PROC | \
 278                             TRACE_GRAPH_PRINT_ABS_TIME | \
 279                             TRACE_GRAPH_PRINT_DURATION)
 280
 281 static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
 282 {
 283         /*
 284          * In graph mode call the graph tracer output function,
 285          * otherwise go with the TRACE_FN event handler
 286          */
 287         if (is_graph())
 288                 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
 289
 290         return TRACE_TYPE_UNHANDLED;
 291 }
 292
 293 static void wakeup_print_header(struct seq_file *s)
 294 {
 295         if (is_graph())
 296                 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
 297         else
 298                 trace_default_header(s);
 299 }
 300
 301 static void
 302 __trace_function(struct trace_array *tr,
 303                  unsigned long ip, unsigned long parent_ip,
 304                  unsigned long flags, int pc)
 305 {
 306         if (is_graph())
 307                 trace_graph_function(tr, ip, parent_ip, flags, pc);
 308         else
 309                 trace_function(tr, ip, parent_ip, flags, pc);
 310 }
 311 #else
 312 #define __trace_function trace_function
 313
 314 static int wakeup_set_flag(u32 old_flags, u32 bit, int set)
 315 {
 316         return -EINVAL;
 317 }
 318
 319 static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
 320 {
 321         return -1;
 322 }
 323
 324 static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
 325 {
 326         return TRACE_TYPE_UNHANDLED;
 327 }
 328
 329 static void wakeup_graph_return(struct ftrace_graph_ret *trace) { }
 330 static void wakeup_trace_open(struct trace_iterator *iter) { }
 331 static void wakeup_trace_close(struct trace_iterator *iter) { }
 332
 333 #ifdef CONFIG_FUNCTION_TRACER
 334 static void wakeup_print_header(struct seq_file *s)
 335 {
 336         trace_default_header(s);
 337 }
 338 #else
 339 static void wakeup_print_header(struct seq_file *s)
 340 {
 341         trace_latency_header(s);
 342 }
 343 #endif /* CONFIG_FUNCTION_TRACER */
 344 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 345
 346 /*
 347  * Should this new latency be reported/recorded?
 348  */
 349 static int report_latency(cycle_t delta)
 350 {
 351         if (tracing_thresh) {
 352                 if (delta < tracing_thresh)
 353                         return 0;
 354         } else {
 355                 if (delta <= tracing_max_latency)
 356                         return 0;
 357         }
 358         return 1;
 359 }
 360
 361 static void
 362 probe_wakeup_migrate_task(void *ignore, struct task_struct *task, int cpu)
 363 {
 364         if (task != wakeup_task)
 365                 return;
 366
 367         wakeup_current_cpu = cpu;
 368 }
 369
 370 static void notrace
 371 probe_wakeup_sched_switch(void *ignore,
 372                           struct task_struct *prev, struct task_struct *next)
 373 {
 374         struct trace_array_cpu *data;
 375         cycle_t T0, T1, delta;
 376         unsigned long flags;
 377         long disabled;
 378         int cpu;
 379         int pc;
 380
 381         tracing_record_cmdline(prev);
 382
 383         if (unlikely(!tracer_enabled))
 384                 return;
 385
 386         /*
 387          * When we start a new trace, we set wakeup_task to NULL
 388          * and then set tracer_enabled = 1. We want to make sure
 389          * that another CPU does not see the tracer_enabled = 1
 390          * and the wakeup_task with an older task, that might
 391          * actually be the same as next.
 392          */
 393         smp_rmb();
 394
 395         if (next != wakeup_task)
 396                 return;
 397
 398         pc = preempt_count();
 399
 400         /* disable local data, not wakeup_cpu data */
 401         cpu = raw_smp_processor_id();
 402         disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
 403         if (likely(disabled != 1))
 404                 goto out;
 405
 406         local_irq_save(flags);
 407         arch_spin_lock(&wakeup_lock);
 408
 409         /* We could race with grabbing wakeup_lock */
 410         if (unlikely(!tracer_enabled || next != wakeup_task))
 411                 goto out_unlock;
 412
 413         /* The task we are waiting for is waking up */
 414         data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu);
 415
 416         __trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc);
 417         tracing_sched_switch_trace(wakeup_trace, prev, next, flags, pc);
 418
 419         T0 = data->preempt_timestamp;
 420         T1 = ftrace_now(cpu);
 421         delta = T1-T0;
 422
 423         if (!report_latency(delta))
 424                 goto out_unlock;
 425
 426         if (likely(!is_tracing_stopped())) {
 427                 tracing_max_latency = delta;
 428                 update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu);
 429         }
 430
 431 out_unlock:
 432         __wakeup_reset(wakeup_trace);
 433         arch_spin_unlock(&wakeup_lock);
 434         local_irq_restore(flags);
 435 out:
 436         atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
 437 }
 438
 439 static void __wakeup_reset(struct trace_array *tr)
 440 {
 441         wakeup_cpu = -1;
 442         wakeup_prio = -1;
 443         tracing_dl = 0;
 444
 445         if (wakeup_task)
 446                 put_task_struct(wakeup_task);
 447
 448         wakeup_task = NULL;
 449 }
 450
 451 static void wakeup_reset(struct trace_array *tr)
 452 {
 453         unsigned long flags;
 454
 455         tracing_reset_online_cpus(&tr->trace_buffer);
 456
 457         local_irq_save(flags);
 458         arch_spin_lock(&wakeup_lock);
 459         __wakeup_reset(tr);
 460         arch_spin_unlock(&wakeup_lock);
 461         local_irq_restore(flags);
 462 }
 463
 464 static void
 465 probe_wakeup(void *ignore, struct task_struct *p, int success)
 466 {
 467         struct trace_array_cpu *data;
 468         int cpu = smp_processor_id();
 469         unsigned long flags;
 470         long disabled;
 471         int pc;
 472
 473         if (likely(!tracer_enabled))
 474                 return;
 475
 476         tracing_record_cmdline(p);
 477         tracing_record_cmdline(current);
 478
 479         /*
 480          * Semantic is like this:
 481          *  - wakeup tracer handles all tasks in the system, independently
 482          *    from their scheduling class;
 483          *  - wakeup_rt tracer handles tasks belonging to sched_dl and
 484          *    sched_rt class;
 485          *  - wakeup_dl handles tasks belonging to sched_dl class only.
 486          */
 487         if (tracing_dl || (wakeup_dl && !dl_task(p)) ||
 488             (wakeup_rt && !dl_task(p) && !rt_task(p)) ||
 489             (!dl_task(p) && (p->prio >= wakeup_prio || p->prio >= current->prio)))
 490                 return;
 491
 492         pc = preempt_count();
 493         disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
 494         if (unlikely(disabled != 1))
 495                 goto out;
 496
 497         /* interrupts should be off from try_to_wake_up */
 498         arch_spin_lock(&wakeup_lock);
 499
 500         /* check for races. */
 501         if (!tracer_enabled || tracing_dl ||
 502             (!dl_task(p) && p->prio >= wakeup_prio))
 503                 goto out_locked;
 504
 505         /* reset the trace */
 506         __wakeup_reset(wakeup_trace);
 507
 508         wakeup_cpu = task_cpu(p);
 509         wakeup_current_cpu = wakeup_cpu;
 510         wakeup_prio = p->prio;
 511
 512         /*
 513          * Once you start tracing a -deadline task, don't bother tracing
 514          * another task until the first one wakes up.
 515          */
 516         if (dl_task(p))
 517                 tracing_dl = 1;
 518         else
 519                 tracing_dl = 0;
 520
 521         wakeup_task = p;
 522         get_task_struct(wakeup_task);
 523
 524         local_save_flags(flags);
 525
 526         data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu);
 527         data->preempt_timestamp = ftrace_now(cpu);
 528         tracing_sched_wakeup_trace(wakeup_trace, p, current, flags, pc);
 529
 530         /*
 531          * We must be careful in using CALLER_ADDR2. But since wake_up
 532          * is not called by an assembly function  (where as schedule is)
 533          * it should be safe to use it here.
 534          */
 535         __trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, flags, pc);
 536
 537 out_locked:
 538         arch_spin_unlock(&wakeup_lock);
 539 out:
 540         atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
 541 }
 542
 543 static void start_wakeup_tracer(struct trace_array *tr)
 544 {
 545         int ret;
 546
 547         ret = register_trace_sched_wakeup(probe_wakeup, NULL);
 548         if (ret) {
 549                 pr_info("wakeup trace: Couldn't activate tracepoint"
 550                         " probe to kernel_sched_wakeup\n");
 551                 return;
 552         }
 553
 554         ret = register_trace_sched_wakeup_new(probe_wakeup, NULL);
 555         if (ret) {
 556                 pr_info("wakeup trace: Couldn't activate tracepoint"
 557                         " probe to kernel_sched_wakeup_new\n");
 558                 goto fail_deprobe;
 559         }
 560
 561         ret = register_trace_sched_switch(probe_wakeup_sched_switch, NULL);
 562         if (ret) {
 563                 pr_info("sched trace: Couldn't activate tracepoint"
 564                         " probe to kernel_sched_switch\n");
 565                 goto fail_deprobe_wake_new;
 566         }
 567
 568         ret = register_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
 569         if (ret) {
 570                 pr_info("wakeup trace: Couldn't activate tracepoint"
 571                         " probe to kernel_sched_migrate_task\n");
 572                 return;
 573         }
 574
 575         wakeup_reset(tr);
 576
 577         /*
 578          * Don't let the tracer_enabled = 1 show up before
 579          * the wakeup_task is reset. This may be overkill since
 580          * wakeup_reset does a spin_unlock after setting the
 581          * wakeup_task to NULL, but I want to be safe.
 582          * This is a slow path anyway.
 583          */
 584         smp_wmb();
 585
 586         if (start_func_tracer(is_graph()))
 587                 printk(KERN_ERR "failed to start wakeup tracer\n");
 588
 589         return;
 590 fail_deprobe_wake_new:
 591         unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
 592 fail_deprobe:
 593         unregister_trace_sched_wakeup(probe_wakeup, NULL);
 594 }
 595
 596 static void stop_wakeup_tracer(struct trace_array *tr)
 597 {
 598         tracer_enabled = 0;
 599         stop_func_tracer(is_graph());
 600         unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
 601         unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
 602         unregister_trace_sched_wakeup(probe_wakeup, NULL);
 603         unregister_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
 604 }
 605
 606 static int __wakeup_tracer_init(struct trace_array *tr)
 607 {
 608         save_flags = trace_flags;
 609
 610         /* non overwrite screws up the latency tracers */
 611         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
 612         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
 613
 614         tracing_max_latency = 0;
 615         wakeup_trace = tr;
 616         start_wakeup_tracer(tr);
 617         return 0;
 618 }
 619
 620 static int wakeup_tracer_init(struct trace_array *tr)
 621 {
 622         wakeup_dl = 0;
 623         wakeup_rt = 0;
 624         return __wakeup_tracer_init(tr);
 625 }
 626
 627 static int wakeup_rt_tracer_init(struct trace_array *tr)
 628 {
 629         wakeup_dl = 0;
 630         wakeup_rt = 1;
 631         return __wakeup_tracer_init(tr);
 632 }
 633
 634 static int wakeup_dl_tracer_init(struct trace_array *tr)
 635 {
 636         wakeup_dl = 1;
 637         wakeup_rt = 0;
 638         return __wakeup_tracer_init(tr);
 639 }
 640
 641 static void wakeup_tracer_reset(struct trace_array *tr)
 642 {
 643         int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
 644         int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
 645
 646         stop_wakeup_tracer(tr);
 647         /* make sure we put back any tasks we are tracing */
 648         wakeup_reset(tr);
 649
 650         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
 651         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
 652 }
 653
 654 static void wakeup_tracer_start(struct trace_array *tr)
 655 {
 656         wakeup_reset(tr);
 657         tracer_enabled = 1;
 658 }
 659
 660 static void wakeup_tracer_stop(struct trace_array *tr)
 661 {
 662         tracer_enabled = 0;
 663 }
 664
 665 static struct tracer wakeup_tracer __read_mostly =
 666 {
 667         .name           = "wakeup",
 668         .init           = wakeup_tracer_init,
 669         .reset          = wakeup_tracer_reset,
 670         .start          = wakeup_tracer_start,
 671         .stop           = wakeup_tracer_stop,
 672         .print_max      = true,
 673         .print_header   = wakeup_print_header,
 674         .print_line     = wakeup_print_line,
 675         .flags          = &tracer_flags,
 676         .set_flag       = wakeup_set_flag,
 677         .flag_changed   = wakeup_flag_changed,
 678 #ifdef CONFIG_FTRACE_SELFTEST
 679         .selftest    = trace_selftest_startup_wakeup,
 680 #endif
 681         .open           = wakeup_trace_open,
 682         .close          = wakeup_trace_close,
 683         .use_max_tr     = true,
 684 };
 685
 686 static struct tracer wakeup_rt_tracer __read_mostly =
 687 {
 688         .name           = "wakeup_rt",
 689         .init           = wakeup_rt_tracer_init,
 690         .reset          = wakeup_tracer_reset,
 691         .start          = wakeup_tracer_start,
 692         .stop           = wakeup_tracer_stop,
 693         .wait_pipe      = poll_wait_pipe,
 694         .print_max      = true,
 695         .print_header   = wakeup_print_header,
 696         .print_line     = wakeup_print_line,
 697         .flags          = &tracer_flags,
 698         .set_flag       = wakeup_set_flag,
 699         .flag_changed   = wakeup_flag_changed,
 700 #ifdef CONFIG_FTRACE_SELFTEST
 701         .selftest    = trace_selftest_startup_wakeup,
 702 #endif
 703         .open           = wakeup_trace_open,
 704         .close          = wakeup_trace_close,
 705         .use_max_tr     = true,
 706 };
 707
 708 static struct tracer wakeup_dl_tracer __read_mostly =
 709 {
 710         .name           = "wakeup_dl",
 711         .init           = wakeup_dl_tracer_init,
 712         .reset          = wakeup_tracer_reset,
 713         .start          = wakeup_tracer_start,
 714         .stop           = wakeup_tracer_stop,
 715         .wait_pipe      = poll_wait_pipe,
 716         .print_max      = true,
 717         .print_header   = wakeup_print_header,
 718         .print_line     = wakeup_print_line,
 719         .flags          = &tracer_flags,
 720         .set_flag       = wakeup_set_flag,
 721         .flag_changed   = wakeup_flag_changed,
 722 #ifdef CONFIG_FTRACE_SELFTEST
 723         .selftest    = trace_selftest_startup_wakeup,
 724 #endif
 725         .open           = wakeup_trace_open,
 726         .close          = wakeup_trace_close,
 727         .use_max_tr     = true,
 728 };
 729
 730 __init static int init_wakeup_tracer(void)
 731 {
 732         int ret;
 733
 734         ret = register_tracer(&wakeup_tracer);
 735         if (ret)
 736                 return ret;
 737
 738         ret = register_tracer(&wakeup_rt_tracer);
 739         if (ret)
 740                 return ret;
 741
 742         ret = register_tracer(&wakeup_dl_tracer);
 743         if (ret)
 744                 return ret;
 745
 746         return 0;
 747 }
 748 core_initcall(init_wakeup_tracer);