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