kernel/trace/trace_sched_wakeup.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * trace task wakeup timings
   4  *
   5  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
   6  * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
   7  *
   8  * Based on code from the latency_tracer, that is:
   9  *
  10  *  Copyright (C) 2004-2006 Ingo Molnar
  11  *  Copyright (C) 2004 Nadia Yvette Chambers
  12  */
  13 #include <linux/module.h>
  14 #include <linux/kallsyms.h>
  15 #include <linux/uaccess.h>
  16 #include <linux/ftrace.h>
  17 #include <linux/sched/rt.h>
  18 #include <linux/sched/deadline.h>
  19 #include <trace/events/sched.h>
  20 #include "trace.h"
  21
  22 static struct trace_array       *wakeup_trace;
  23 static int __read_mostly        tracer_enabled;
  24
  25 static struct task_struct       *wakeup_task;
  26 static int                      wakeup_cpu;
  27 static int                      wakeup_current_cpu;
  28 static unsigned                 wakeup_prio = -1;
  29 static int                      wakeup_rt;
  30 static int                      wakeup_dl;
  31 static int                      tracing_dl = 0;
  32
  33 static arch_spinlock_t wakeup_lock =
  34         (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
  35
  36 static void wakeup_reset(struct trace_array *tr);
  37 static void __wakeup_reset(struct trace_array *tr);
  38 static int start_func_tracer(struct trace_array *tr, int graph);
  39 static void stop_func_tracer(struct trace_array *tr, int graph);
  40
  41 static int save_flags;
  42
  43 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  44 # define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)
  45 #else
  46 # define is_graph(tr) false
  47 #endif
  48
  49 #ifdef CONFIG_FUNCTION_TRACER
  50
  51 static bool function_enabled;
  52
  53 /*
  54  * Prologue for the wakeup function tracers.
  55  *
  56  * Returns 1 if it is OK to continue, and preemption
  57  *            is disabled and data->disabled is incremented.
  58  *         0 if the trace is to be ignored, and preemption
  59  *            is not disabled and data->disabled is
  60  *            kept the same.
  61  *
  62  * Note, this function is also used outside this ifdef but
  63  *  inside the #ifdef of the function graph tracer below.
  64  *  This is OK, since the function graph tracer is
  65  *  dependent on the function tracer.
  66  */
  67 static int
  68 func_prolog_preempt_disable(struct trace_array *tr,
  69                             struct trace_array_cpu **data,
  70                             int *pc)
  71 {
  72         long disabled;
  73         int cpu;
  74
  75         if (likely(!wakeup_task))
  76                 return 0;
  77
  78         *pc = preempt_count();
  79         preempt_disable_notrace();
  80
  81         cpu = raw_smp_processor_id();
  82         if (cpu != wakeup_current_cpu)
  83                 goto out_enable;
  84
  85         *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
  86         disabled = atomic_inc_return(&(*data)->disabled);
  87         if (unlikely(disabled != 1))
  88                 goto out;
  89
  90         return 1;
  91
  92 out:
  93         atomic_dec(&(*data)->disabled);
  94
  95 out_enable:
  96         preempt_enable_notrace();
  97         return 0;
  98 }
  99
 100 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 101
 102 static int wakeup_display_graph(struct trace_array *tr, int set)
 103 {
 104         if (!(is_graph(tr) ^ set))
 105                 return 0;
 106
 107         stop_func_tracer(tr, !set);
 108
 109         wakeup_reset(wakeup_trace);
 110         tr->max_latency = 0;
 111
 112         return start_func_tracer(tr, set);
 113 }
 114
 115 static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
 116 {
 117         struct trace_array *tr = wakeup_trace;
 118         struct trace_array_cpu *data;
 119         unsigned long flags;
 120         int pc, ret = 0;
 121
 122         if (ftrace_graph_ignore_func(trace))
 123                 return 0;
 124         /*
 125          * Do not trace a function if it's filtered by set_graph_notrace.
 126          * Make the index of ret stack negative to indicate that it should
 127          * ignore further functions.  But it needs its own ret stack entry
 128          * to recover the original index in order to continue tracing after
 129          * returning from the function.
 130          */
 131         if (ftrace_graph_notrace_addr(trace->func))
 132                 return 1;
 133
 134         if (!func_prolog_preempt_disable(tr, &data, &pc))
 135                 return 0;
 136
 137         local_save_flags(flags);
 138         ret = __trace_graph_entry(tr, trace, flags, pc);
 139         atomic_dec(&data->disabled);
 140         preempt_enable_notrace();
 141
 142         return ret;
 143 }
 144
 145 static void wakeup_graph_return(struct ftrace_graph_ret *trace)
 146 {
 147         struct trace_array *tr = wakeup_trace;
 148         struct trace_array_cpu *data;
 149         unsigned long flags;
 150         int pc;
 151
 152         ftrace_graph_addr_finish(trace);
 153
 154         if (!func_prolog_preempt_disable(tr, &data, &pc))
 155                 return;
 156
 157         local_save_flags(flags);
 158         __trace_graph_return(tr, trace, flags, pc);
 159         atomic_dec(&data->disabled);
 160
 161         preempt_enable_notrace();
 162         return;
 163 }
 164
 165 static struct fgraph_ops fgraph_wakeup_ops = {
 166         .entryfunc = &wakeup_graph_entry,
 167         .retfunc = &wakeup_graph_return,
 168 };
 169
 170 static void wakeup_trace_open(struct trace_iterator *iter)
 171 {
 172         if (is_graph(iter->tr))
 173                 graph_trace_open(iter);
 174 }
 175
 176 static void wakeup_trace_close(struct trace_iterator *iter)
 177 {
 178         if (iter->private)
 179                 graph_trace_close(iter);
 180 }
 181
 182 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_PROC | \
 183                             TRACE_GRAPH_PRINT_CPU |  \
 184                             TRACE_GRAPH_PRINT_REL_TIME | \
 185                             TRACE_GRAPH_PRINT_DURATION | \
 186                             TRACE_GRAPH_PRINT_OVERHEAD | \
 187                             TRACE_GRAPH_PRINT_IRQS)
 188
 189 static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
 190 {
 191         /*
 192          * In graph mode call the graph tracer output function,
 193          * otherwise go with the TRACE_FN event handler
 194          */
 195         if (is_graph(iter->tr))
 196                 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
 197
 198         return TRACE_TYPE_UNHANDLED;
 199 }
 200
 201 static void wakeup_print_header(struct seq_file *s)
 202 {
 203         if (is_graph(wakeup_trace))
 204                 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
 205         else
 206                 trace_default_header(s);
 207 }
 208 #endif /* else CONFIG_FUNCTION_GRAPH_TRACER */
 209
 210 /*
 211  * wakeup uses its own tracer function to keep the overhead down:
 212  */
 213 static void
 214 wakeup_tracer_call(unsigned long ip, unsigned long parent_ip,
 215                    struct ftrace_ops *op, struct pt_regs *pt_regs)
 216 {
 217         struct trace_array *tr = wakeup_trace;
 218         struct trace_array_cpu *data;
 219         unsigned long flags;
 220         int pc;
 221
 222         if (!func_prolog_preempt_disable(tr, &data, &pc))
 223                 return;
 224
 225         local_irq_save(flags);
 226         trace_function(tr, ip, parent_ip, flags, pc);
 227         local_irq_restore(flags);
 228
 229         atomic_dec(&data->disabled);
 230         preempt_enable_notrace();
 231 }
 232
 233 static int register_wakeup_function(struct trace_array *tr, int graph, int set)
 234 {
 235         int ret;
 236
 237         /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
 238         if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
 239                 return 0;
 240
 241         if (graph)
 242                 ret = register_ftrace_graph(&fgraph_wakeup_ops);
 243         else
 244                 ret = register_ftrace_function(tr->ops);
 245
 246         if (!ret)
 247                 function_enabled = true;
 248
 249         return ret;
 250 }
 251
 252 static void unregister_wakeup_function(struct trace_array *tr, int graph)
 253 {
 254         if (!function_enabled)
 255                 return;
 256
 257         if (graph)
 258                 unregister_ftrace_graph(&fgraph_wakeup_ops);
 259         else
 260                 unregister_ftrace_function(tr->ops);
 261
 262         function_enabled = false;
 263 }
 264
 265 static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
 266 {
 267         if (!(mask & TRACE_ITER_FUNCTION))
 268                 return 0;
 269
 270         if (set)
 271                 register_wakeup_function(tr, is_graph(tr), 1);
 272         else
 273                 unregister_wakeup_function(tr, is_graph(tr));
 274         return 1;
 275 }
 276 #else /* CONFIG_FUNCTION_TRACER */
 277 static int register_wakeup_function(struct trace_array *tr, int graph, int set)
 278 {
 279         return 0;
 280 }
 281 static void unregister_wakeup_function(struct trace_array *tr, int graph) { }
 282 static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
 283 {
 284         return 0;
 285 }
 286 #endif /* else CONFIG_FUNCTION_TRACER */
 287
 288 #ifndef CONFIG_FUNCTION_GRAPH_TRACER
 289 static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
 290 {
 291         return TRACE_TYPE_UNHANDLED;
 292 }
 293
 294 static void wakeup_trace_open(struct trace_iterator *iter) { }
 295 static void wakeup_trace_close(struct trace_iterator *iter) { }
 296
 297 static void wakeup_print_header(struct seq_file *s)
 298 {
 299         trace_default_header(s);
 300 }
 301 #endif /* !CONFIG_FUNCTION_GRAPH_TRACER */
 302
 303 static void
 304 __trace_function(struct trace_array *tr,
 305                  unsigned long ip, unsigned long parent_ip,
 306                  unsigned long flags, int pc)
 307 {
 308         if (is_graph(tr))
 309                 trace_graph_function(tr, ip, parent_ip, flags, pc);
 310         else
 311                 trace_function(tr, ip, parent_ip, flags, pc);
 312 }
 313
 314 static int wakeup_flag_changed(struct trace_array *tr, u32 mask, int set)
 315 {
 316         struct tracer *tracer = tr->current_trace;
 317
 318         if (wakeup_function_set(tr, mask, set))
 319                 return 0;
 320
 321 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 322         if (mask & TRACE_ITER_DISPLAY_GRAPH)
 323                 return wakeup_display_graph(tr, set);
 324 #endif
 325
 326         return trace_keep_overwrite(tracer, mask, set);
 327 }
 328
 329 static int start_func_tracer(struct trace_array *tr, int graph)
 330 {
 331         int ret;
 332
 333         ret = register_wakeup_function(tr, graph, 0);
 334
 335         if (!ret && tracing_is_enabled())
 336                 tracer_enabled = 1;
 337         else
 338                 tracer_enabled = 0;
 339
 340         return ret;
 341 }
 342
 343 static void stop_func_tracer(struct trace_array *tr, int graph)
 344 {
 345         tracer_enabled = 0;
 346
 347         unregister_wakeup_function(tr, graph);
 348 }
 349
 350 /*
 351  * Should this new latency be reported/recorded?
 352  */
 353 static bool report_latency(struct trace_array *tr, u64 delta)
 354 {
 355         if (tracing_thresh) {
 356                 if (delta < tracing_thresh)
 357                         return false;
 358         } else {
 359                 if (delta <= tr->max_latency)
 360                         return false;
 361         }
 362         return true;
 363 }
 364
 365 static void
 366 probe_wakeup_migrate_task(void *ignore, struct task_struct *task, int cpu)
 367 {
 368         if (task != wakeup_task)
 369                 return;
 370
 371         wakeup_current_cpu = cpu;
 372 }
 373
 374 static void
 375 tracing_sched_switch_trace(struct trace_array *tr,
 376                            struct task_struct *prev,
 377                            struct task_struct *next,
 378                            unsigned long flags, int pc)
 379 {
 380         struct trace_event_call *call = &event_context_switch;
 381         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 382         struct ring_buffer_event *event;
 383         struct ctx_switch_entry *entry;
 384
 385         event = trace_buffer_lock_reserve(buffer, TRACE_CTX,
 386                                           sizeof(*entry), flags, pc);
 387         if (!event)
 388                 return;
 389         entry   = ring_buffer_event_data(event);
 390         entry->prev_pid                 = prev->pid;
 391         entry->prev_prio                = prev->prio;
 392         entry->prev_state               = task_state_index(prev);
 393         entry->next_pid                 = next->pid;
 394         entry->next_prio                = next->prio;
 395         entry->next_state               = task_state_index(next);
 396         entry->next_cpu = task_cpu(next);
 397
 398         if (!call_filter_check_discard(call, entry, buffer, event))
 399                 trace_buffer_unlock_commit(tr, buffer, event, flags, pc);
 400 }
 401
 402 static void
 403 tracing_sched_wakeup_trace(struct trace_array *tr,
 404                            struct task_struct *wakee,
 405                            struct task_struct *curr,
 406                            unsigned long flags, int pc)
 407 {
 408         struct trace_event_call *call = &event_wakeup;
 409         struct ring_buffer_event *event;
 410         struct ctx_switch_entry *entry;
 411         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 412
 413         event = trace_buffer_lock_reserve(buffer, TRACE_WAKE,
 414                                           sizeof(*entry), flags, pc);
 415         if (!event)
 416                 return;
 417         entry   = ring_buffer_event_data(event);
 418         entry->prev_pid                 = curr->pid;
 419         entry->prev_prio                = curr->prio;
 420         entry->prev_state               = task_state_index(curr);
 421         entry->next_pid                 = wakee->pid;
 422         entry->next_prio                = wakee->prio;
 423         entry->next_state               = task_state_index(wakee);
 424         entry->next_cpu                 = task_cpu(wakee);
 425
 426         if (!call_filter_check_discard(call, entry, buffer, event))
 427                 trace_buffer_unlock_commit(tr, buffer, event, flags, pc);
 428 }
 429
 430 static void notrace
 431 probe_wakeup_sched_switch(void *ignore, bool preempt,
 432                           struct task_struct *prev, struct task_struct *next)
 433 {
 434         struct trace_array_cpu *data;
 435         u64 T0, T1, delta;
 436         unsigned long flags;
 437         long disabled;
 438         int cpu;
 439         int pc;
 440
 441         tracing_record_cmdline(prev);
 442
 443         if (unlikely(!tracer_enabled))
 444                 return;
 445
 446         /*
 447          * When we start a new trace, we set wakeup_task to NULL
 448          * and then set tracer_enabled = 1. We want to make sure
 449          * that another CPU does not see the tracer_enabled = 1
 450          * and the wakeup_task with an older task, that might
 451          * actually be the same as next.
 452          */
 453         smp_rmb();
 454
 455         if (next != wakeup_task)
 456                 return;
 457
 458         pc = preempt_count();
 459
 460         /* disable local data, not wakeup_cpu data */
 461         cpu = raw_smp_processor_id();
 462         disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
 463         if (likely(disabled != 1))
 464                 goto out;
 465
 466         local_irq_save(flags);
 467         arch_spin_lock(&wakeup_lock);
 468
 469         /* We could race with grabbing wakeup_lock */
 470         if (unlikely(!tracer_enabled || next != wakeup_task))
 471                 goto out_unlock;
 472
 473         /* The task we are waiting for is waking up */
 474         data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu);
 475
 476         __trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc);
 477         tracing_sched_switch_trace(wakeup_trace, prev, next, flags, pc);
 478         __trace_stack(wakeup_trace, flags, 0, pc);
 479
 480         T0 = data->preempt_timestamp;
 481         T1 = ftrace_now(cpu);
 482         delta = T1-T0;
 483
 484         if (!report_latency(wakeup_trace, delta))
 485                 goto out_unlock;
 486
 487         if (likely(!is_tracing_stopped())) {
 488                 wakeup_trace->max_latency = delta;
 489                 update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu, NULL);
 490         }
 491
 492 out_unlock:
 493         __wakeup_reset(wakeup_trace);
 494         arch_spin_unlock(&wakeup_lock);
 495         local_irq_restore(flags);
 496 out:
 497         atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
 498 }
 499
 500 static void __wakeup_reset(struct trace_array *tr)
 501 {
 502         wakeup_cpu = -1;
 503         wakeup_prio = -1;
 504         tracing_dl = 0;
 505
 506         if (wakeup_task)
 507                 put_task_struct(wakeup_task);
 508
 509         wakeup_task = NULL;
 510 }
 511
 512 static void wakeup_reset(struct trace_array *tr)
 513 {
 514         unsigned long flags;
 515
 516         tracing_reset_online_cpus(&tr->trace_buffer);
 517
 518         local_irq_save(flags);
 519         arch_spin_lock(&wakeup_lock);
 520         __wakeup_reset(tr);
 521         arch_spin_unlock(&wakeup_lock);
 522         local_irq_restore(flags);
 523 }
 524
 525 static void
 526 probe_wakeup(void *ignore, struct task_struct *p)
 527 {
 528         struct trace_array_cpu *data;
 529         int cpu = smp_processor_id();
 530         unsigned long flags;
 531         long disabled;
 532         int pc;
 533
 534         if (likely(!tracer_enabled))
 535                 return;
 536
 537         tracing_record_cmdline(p);
 538         tracing_record_cmdline(current);
 539
 540         /*
 541          * Semantic is like this:
 542          *  - wakeup tracer handles all tasks in the system, independently
 543          *    from their scheduling class;
 544          *  - wakeup_rt tracer handles tasks belonging to sched_dl and
 545          *    sched_rt class;
 546          *  - wakeup_dl handles tasks belonging to sched_dl class only.
 547          */
 548         if (tracing_dl || (wakeup_dl && !dl_task(p)) ||
 549             (wakeup_rt && !dl_task(p) && !rt_task(p)) ||
 550             (!dl_task(p) && (p->prio >= wakeup_prio || p->prio >= current->prio)))
 551                 return;
 552
 553         pc = preempt_count();
 554         disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
 555         if (unlikely(disabled != 1))
 556                 goto out;
 557
 558         /* interrupts should be off from try_to_wake_up */
 559         arch_spin_lock(&wakeup_lock);
 560
 561         /* check for races. */
 562         if (!tracer_enabled || tracing_dl ||
 563             (!dl_task(p) && p->prio >= wakeup_prio))
 564                 goto out_locked;
 565
 566         /* reset the trace */
 567         __wakeup_reset(wakeup_trace);
 568
 569         wakeup_cpu = task_cpu(p);
 570         wakeup_current_cpu = wakeup_cpu;
 571         wakeup_prio = p->prio;
 572
 573         /*
 574          * Once you start tracing a -deadline task, don't bother tracing
 575          * another task until the first one wakes up.
 576          */
 577         if (dl_task(p))
 578                 tracing_dl = 1;
 579         else
 580                 tracing_dl = 0;
 581
 582         wakeup_task = p;
 583         get_task_struct(wakeup_task);
 584
 585         local_save_flags(flags);
 586
 587         data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu);
 588         data->preempt_timestamp = ftrace_now(cpu);
 589         tracing_sched_wakeup_trace(wakeup_trace, p, current, flags, pc);
 590         __trace_stack(wakeup_trace, flags, 0, pc);
 591
 592         /*
 593          * We must be careful in using CALLER_ADDR2. But since wake_up
 594          * is not called by an assembly function  (where as schedule is)
 595          * it should be safe to use it here.
 596          */
 597         __trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, flags, pc);
 598
 599 out_locked:
 600         arch_spin_unlock(&wakeup_lock);
 601 out:
 602         atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
 603 }
 604
 605 static void start_wakeup_tracer(struct trace_array *tr)
 606 {
 607         int ret;
 608
 609         ret = register_trace_sched_wakeup(probe_wakeup, NULL);
 610         if (ret) {
 611                 pr_info("wakeup trace: Couldn't activate tracepoint"
 612                         " probe to kernel_sched_wakeup\n");
 613                 return;
 614         }
 615
 616         ret = register_trace_sched_wakeup_new(probe_wakeup, NULL);
 617         if (ret) {
 618                 pr_info("wakeup trace: Couldn't activate tracepoint"
 619                         " probe to kernel_sched_wakeup_new\n");
 620                 goto fail_deprobe;
 621         }
 622
 623         ret = register_trace_sched_switch(probe_wakeup_sched_switch, NULL);
 624         if (ret) {
 625                 pr_info("sched trace: Couldn't activate tracepoint"
 626                         " probe to kernel_sched_switch\n");
 627                 goto fail_deprobe_wake_new;
 628         }
 629
 630         ret = register_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
 631         if (ret) {
 632                 pr_info("wakeup trace: Couldn't activate tracepoint"
 633                         " probe to kernel_sched_migrate_task\n");
 634                 return;
 635         }
 636
 637         wakeup_reset(tr);
 638
 639         /*
 640          * Don't let the tracer_enabled = 1 show up before
 641          * the wakeup_task is reset. This may be overkill since
 642          * wakeup_reset does a spin_unlock after setting the
 643          * wakeup_task to NULL, but I want to be safe.
 644          * This is a slow path anyway.
 645          */
 646         smp_wmb();
 647
 648         if (start_func_tracer(tr, is_graph(tr)))
 649                 printk(KERN_ERR "failed to start wakeup tracer\n");
 650
 651         return;
 652 fail_deprobe_wake_new:
 653         unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
 654 fail_deprobe:
 655         unregister_trace_sched_wakeup(probe_wakeup, NULL);
 656 }
 657
 658 static void stop_wakeup_tracer(struct trace_array *tr)
 659 {
 660         tracer_enabled = 0;
 661         stop_func_tracer(tr, is_graph(tr));
 662         unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
 663         unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
 664         unregister_trace_sched_wakeup(probe_wakeup, NULL);
 665         unregister_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
 666 }
 667
 668 static bool wakeup_busy;
 669
 670 static int __wakeup_tracer_init(struct trace_array *tr)
 671 {
 672         save_flags = tr->trace_flags;
 673
 674         /* non overwrite screws up the latency tracers */
 675         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
 676         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
 677
 678         tr->max_latency = 0;
 679         wakeup_trace = tr;
 680         ftrace_init_array_ops(tr, wakeup_tracer_call);
 681         start_wakeup_tracer(tr);
 682
 683         wakeup_busy = true;
 684         return 0;
 685 }
 686
 687 static int wakeup_tracer_init(struct trace_array *tr)
 688 {
 689         if (wakeup_busy)
 690                 return -EBUSY;
 691
 692         wakeup_dl = 0;
 693         wakeup_rt = 0;
 694         return __wakeup_tracer_init(tr);
 695 }
 696
 697 static int wakeup_rt_tracer_init(struct trace_array *tr)
 698 {
 699         if (wakeup_busy)
 700                 return -EBUSY;
 701
 702         wakeup_dl = 0;
 703         wakeup_rt = 1;
 704         return __wakeup_tracer_init(tr);
 705 }
 706
 707 static int wakeup_dl_tracer_init(struct trace_array *tr)
 708 {
 709         if (wakeup_busy)
 710                 return -EBUSY;
 711
 712         wakeup_dl = 1;
 713         wakeup_rt = 0;
 714         return __wakeup_tracer_init(tr);
 715 }
 716
 717 static void wakeup_tracer_reset(struct trace_array *tr)
 718 {
 719         int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
 720         int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
 721
 722         stop_wakeup_tracer(tr);
 723         /* make sure we put back any tasks we are tracing */
 724         wakeup_reset(tr);
 725
 726         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
 727         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
 728         ftrace_reset_array_ops(tr);
 729         wakeup_busy = false;
 730 }
 731
 732 static void wakeup_tracer_start(struct trace_array *tr)
 733 {
 734         wakeup_reset(tr);
 735         tracer_enabled = 1;
 736 }
 737
 738 static void wakeup_tracer_stop(struct trace_array *tr)
 739 {
 740         tracer_enabled = 0;
 741 }
 742
 743 static struct tracer wakeup_tracer __read_mostly =
 744 {
 745         .name           = "wakeup",
 746         .init           = wakeup_tracer_init,
 747         .reset          = wakeup_tracer_reset,
 748         .start          = wakeup_tracer_start,
 749         .stop           = wakeup_tracer_stop,
 750         .print_max      = true,
 751         .print_header   = wakeup_print_header,
 752         .print_line     = wakeup_print_line,
 753         .flag_changed   = wakeup_flag_changed,
 754 #ifdef CONFIG_FTRACE_SELFTEST
 755         .selftest    = trace_selftest_startup_wakeup,
 756 #endif
 757         .open           = wakeup_trace_open,
 758         .close          = wakeup_trace_close,
 759         .allow_instances = true,
 760         .use_max_tr     = true,
 761 };
 762
 763 static struct tracer wakeup_rt_tracer __read_mostly =
 764 {
 765         .name           = "wakeup_rt",
 766         .init           = wakeup_rt_tracer_init,
 767         .reset          = wakeup_tracer_reset,
 768         .start          = wakeup_tracer_start,
 769         .stop           = wakeup_tracer_stop,
 770         .print_max      = true,
 771         .print_header   = wakeup_print_header,
 772         .print_line     = wakeup_print_line,
 773         .flag_changed   = wakeup_flag_changed,
 774 #ifdef CONFIG_FTRACE_SELFTEST
 775         .selftest    = trace_selftest_startup_wakeup,
 776 #endif
 777         .open           = wakeup_trace_open,
 778         .close          = wakeup_trace_close,
 779         .allow_instances = true,
 780         .use_max_tr     = true,
 781 };
 782
 783 static struct tracer wakeup_dl_tracer __read_mostly =
 784 {
 785         .name           = "wakeup_dl",
 786         .init           = wakeup_dl_tracer_init,
 787         .reset          = wakeup_tracer_reset,
 788         .start          = wakeup_tracer_start,
 789         .stop           = wakeup_tracer_stop,
 790         .print_max      = true,
 791         .print_header   = wakeup_print_header,
 792         .print_line     = wakeup_print_line,
 793         .flag_changed   = wakeup_flag_changed,
 794 #ifdef CONFIG_FTRACE_SELFTEST
 795         .selftest    = trace_selftest_startup_wakeup,
 796 #endif
 797         .open           = wakeup_trace_open,
 798         .close          = wakeup_trace_close,
 799         .allow_instances = true,
 800         .use_max_tr     = true,
 801 };
 802
 803 __init static int init_wakeup_tracer(void)
 804 {
 805         int ret;
 806
 807         ret = register_tracer(&wakeup_tracer);
 808         if (ret)
 809                 return ret;
 810
 811         ret = register_tracer(&wakeup_rt_tracer);
 812         if (ret)
 813                 return ret;
 814
 815         ret = register_tracer(&wakeup_dl_tracer);
 816         if (ret)
 817                 return ret;
 818
 819         return 0;
 820 }
 821 core_initcall(init_wakeup_tracer);