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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
22static struct trace_array *wakeup_trace;
23static int __read_mostly tracer_enabled;
24
25static struct task_struct *wakeup_task;
26static int wakeup_cpu;
27static int wakeup_current_cpu;
28static unsigned wakeup_prio = -1;
29static bool wakeup_rt;
30static bool wakeup_dl;
31static bool tracing_dl;
32
33static arch_spinlock_t wakeup_lock =
34 (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
35
36static void wakeup_reset(struct trace_array *tr);
37static void __wakeup_reset(struct trace_array *tr);
38static int start_func_tracer(struct trace_array *tr, int graph);
39static void stop_func_tracer(struct trace_array *tr, int graph);
40
41static 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
51static 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 */
67static int
68func_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
92out:
93 atomic_dec(&(*data)->disabled);
94
95out_enable:
96 preempt_enable_notrace();
97 return 0;
98}
99
100#ifdef CONFIG_FUNCTION_GRAPH_TRACER
101
102static 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
115static 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
144static 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
162static struct fgraph_ops fgraph_wakeup_ops = {
163 .entryfunc = &wakeup_graph_entry,
164 .retfunc = &wakeup_graph_return,
165};
166
167static void wakeup_trace_open(struct trace_iterator *iter)
168{
169 if (is_graph(iter->tr))
170 graph_trace_open(iter);
171}
172
173static 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
186static 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
198static 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 */
210static void
211wakeup_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
230static 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
249static 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
262static 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 */
274static int register_wakeup_function(struct trace_array *tr, int graph, int set)
275{
276 return 0;
277}
278static void unregister_wakeup_function(struct trace_array *tr, int graph) { }
279static 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
286static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
287{
288 return TRACE_TYPE_UNHANDLED;
289}
290
291static void wakeup_trace_open(struct trace_iterator *iter) { }
292static void wakeup_trace_close(struct trace_iterator *iter) { }
293
294static void wakeup_print_header(struct seq_file *s)
295{
296 trace_default_header(s);
297}
298#endif /* !CONFIG_FUNCTION_GRAPH_TRACER */
299
300static 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
311static 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
326static 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
340static 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 */
350static 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
362static void
363probe_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
371static void
372tracing_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
399static void
400tracing_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
427static void notrace
428probe_wakeup_sched_switch(void *ignore, bool preempt,
429 struct task_struct *prev, struct task_struct *next,
430 unsigned int prev_state)
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
490out_unlock:
491 __wakeup_reset(wakeup_trace);
492 arch_spin_unlock(&wakeup_lock);
493 local_irq_restore(flags);
494out:
495 atomic_dec(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
496}
497
498static 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
510static 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
523static void
524probe_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
594out_locked:
595 arch_spin_unlock(&wakeup_lock);
596out:
597 atomic_dec(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
598}
599
600static 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;
647fail_deprobe_sched_switch:
648 unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
649fail_deprobe_wake_new:
650 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
651fail_deprobe:
652 unregister_trace_sched_wakeup(probe_wakeup, NULL);
653}
654
655static 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
665static bool wakeup_busy;
666
667static 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
684static 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
694static 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
704static 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
714static 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
729static void wakeup_tracer_start(struct trace_array *tr)
730{
731 wakeup_reset(tr);
732 tracer_enabled = 1;
733}
734
735static void wakeup_tracer_stop(struct trace_array *tr)
736{
737 tracer_enabled = 0;
738}
739
740static 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
760static 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
780static 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}
818core_initcall(init_wakeup_tracer);
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
21static struct trace_array *wakeup_trace;
22static int __read_mostly tracer_enabled;
23
24static struct task_struct *wakeup_task;
25static int wakeup_cpu;
26static int wakeup_current_cpu;
27static unsigned wakeup_prio = -1;
28static int wakeup_rt;
29static int wakeup_dl;
30static int tracing_dl = 0;
31
32static arch_spinlock_t wakeup_lock =
33 (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
34
35static void wakeup_reset(struct trace_array *tr);
36static void __wakeup_reset(struct trace_array *tr);
37
38static int save_flags;
39
40#ifdef CONFIG_FUNCTION_GRAPH_TRACER
41static int wakeup_display_graph(struct trace_array *tr, int set);
42# define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)
43#else
44static 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
54static int wakeup_graph_entry(struct ftrace_graph_ent *trace);
55static void wakeup_graph_return(struct ftrace_graph_ret *trace);
56
57static 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 */
73static int
74func_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
98out:
99 atomic_dec(&(*data)->disabled);
100
101out_enable:
102 preempt_enable_notrace();
103 return 0;
104}
105
106/*
107 * wakeup uses its own tracer function to keep the overhead down:
108 */
109static void
110wakeup_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
129static 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
149static 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
162static 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
174static int register_wakeup_function(struct trace_array *tr, int graph, int set)
175{
176 return 0;
177}
178static void unregister_wakeup_function(struct trace_array *tr, int graph) { }
179static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
180{
181 return 0;
182}
183#endif /* CONFIG_FUNCTION_TRACER */
184
185static 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
200static 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
214static 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
222static 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
235static 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
253static 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
271static void wakeup_trace_open(struct trace_iterator *iter)
272{
273 if (is_graph(iter->tr))
274 graph_trace_open(iter);
275}
276
277static 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
287static 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
299static 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
307static 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
320static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
321{
322 return TRACE_TYPE_UNHANDLED;
323}
324
325static void wakeup_trace_open(struct trace_iterator *iter) { }
326static void wakeup_trace_close(struct trace_iterator *iter) { }
327
328#ifdef CONFIG_FUNCTION_TRACER
329static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
330{
331 return -1;
332}
333static void wakeup_graph_return(struct ftrace_graph_ret *trace) { }
334static void wakeup_print_header(struct seq_file *s)
335{
336 trace_default_header(s);
337}
338#else
339static 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 */
349static 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
361static void
362probe_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
370static void
371tracing_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
398static void
399tracing_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
426static void notrace
427probe_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
487out_unlock:
488 __wakeup_reset(wakeup_trace);
489 arch_spin_unlock(&wakeup_lock);
490 local_irq_restore(flags);
491out:
492 atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
493}
494
495static 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
507static 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
520static void
521probe_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
593out_locked:
594 arch_spin_unlock(&wakeup_lock);
595out:
596 atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
597}
598
599static 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;
646fail_deprobe_wake_new:
647 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
648fail_deprobe:
649 unregister_trace_sched_wakeup(probe_wakeup, NULL);
650}
651
652static 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
662static bool wakeup_busy;
663
664static 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
681static 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
691static 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
701static 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
711static 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
726static void wakeup_tracer_start(struct trace_array *tr)
727{
728 wakeup_reset(tr);
729 tracer_enabled = 1;
730}
731
732static void wakeup_tracer_stop(struct trace_array *tr)
733{
734 tracer_enabled = 0;
735}
736
737static 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
757static 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
777static 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}
814core_initcall(init_wakeup_tracer);