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