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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 int wakeup_rt;
30static int wakeup_dl;
31static int tracing_dl = 0;
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);
38
39static int save_flags;
40
41#ifdef CONFIG_FUNCTION_GRAPH_TRACER
42static int wakeup_display_graph(struct trace_array *tr, int set);
43# define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)
44#else
45static inline int wakeup_display_graph(struct trace_array *tr, int set)
46{
47 return 0;
48}
49# define is_graph(tr) false
50#endif
51
52
53#ifdef CONFIG_FUNCTION_TRACER
54
55static int wakeup_graph_entry(struct ftrace_graph_ent *trace);
56static void wakeup_graph_return(struct ftrace_graph_ret *trace);
57
58static bool function_enabled;
59
60/*
61 * Prologue for the wakeup function tracers.
62 *
63 * Returns 1 if it is OK to continue, and preemption
64 * is disabled and data->disabled is incremented.
65 * 0 if the trace is to be ignored, and preemption
66 * is not disabled and data->disabled is
67 * kept the same.
68 *
69 * Note, this function is also used outside this ifdef but
70 * inside the #ifdef of the function graph tracer below.
71 * This is OK, since the function graph tracer is
72 * dependent on the function tracer.
73 */
74static int
75func_prolog_preempt_disable(struct trace_array *tr,
76 struct trace_array_cpu **data,
77 int *pc)
78{
79 long disabled;
80 int cpu;
81
82 if (likely(!wakeup_task))
83 return 0;
84
85 *pc = preempt_count();
86 preempt_disable_notrace();
87
88 cpu = raw_smp_processor_id();
89 if (cpu != wakeup_current_cpu)
90 goto out_enable;
91
92 *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
93 disabled = atomic_inc_return(&(*data)->disabled);
94 if (unlikely(disabled != 1))
95 goto out;
96
97 return 1;
98
99out:
100 atomic_dec(&(*data)->disabled);
101
102out_enable:
103 preempt_enable_notrace();
104 return 0;
105}
106
107/*
108 * wakeup uses its own tracer function to keep the overhead down:
109 */
110static void
111wakeup_tracer_call(unsigned long ip, unsigned long parent_ip,
112 struct ftrace_ops *op, struct pt_regs *pt_regs)
113{
114 struct trace_array *tr = wakeup_trace;
115 struct trace_array_cpu *data;
116 unsigned long flags;
117 int pc;
118
119 if (!func_prolog_preempt_disable(tr, &data, &pc))
120 return;
121
122 local_irq_save(flags);
123 trace_function(tr, ip, parent_ip, flags, pc);
124 local_irq_restore(flags);
125
126 atomic_dec(&data->disabled);
127 preempt_enable_notrace();
128}
129
130static int register_wakeup_function(struct trace_array *tr, int graph, int set)
131{
132 int ret;
133
134 /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
135 if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
136 return 0;
137
138 if (graph)
139 ret = register_ftrace_graph(&wakeup_graph_return,
140 &wakeup_graph_entry);
141 else
142 ret = register_ftrace_function(tr->ops);
143
144 if (!ret)
145 function_enabled = true;
146
147 return ret;
148}
149
150static void unregister_wakeup_function(struct trace_array *tr, int graph)
151{
152 if (!function_enabled)
153 return;
154
155 if (graph)
156 unregister_ftrace_graph();
157 else
158 unregister_ftrace_function(tr->ops);
159
160 function_enabled = false;
161}
162
163static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
164{
165 if (!(mask & TRACE_ITER_FUNCTION))
166 return 0;
167
168 if (set)
169 register_wakeup_function(tr, is_graph(tr), 1);
170 else
171 unregister_wakeup_function(tr, is_graph(tr));
172 return 1;
173}
174#else
175static int register_wakeup_function(struct trace_array *tr, int graph, int set)
176{
177 return 0;
178}
179static void unregister_wakeup_function(struct trace_array *tr, int graph) { }
180static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
181{
182 return 0;
183}
184#endif /* CONFIG_FUNCTION_TRACER */
185
186static int wakeup_flag_changed(struct trace_array *tr, u32 mask, int set)
187{
188 struct tracer *tracer = tr->current_trace;
189
190 if (wakeup_function_set(tr, mask, set))
191 return 0;
192
193#ifdef CONFIG_FUNCTION_GRAPH_TRACER
194 if (mask & TRACE_ITER_DISPLAY_GRAPH)
195 return wakeup_display_graph(tr, set);
196#endif
197
198 return trace_keep_overwrite(tracer, mask, set);
199}
200
201static int start_func_tracer(struct trace_array *tr, int graph)
202{
203 int ret;
204
205 ret = register_wakeup_function(tr, graph, 0);
206
207 if (!ret && tracing_is_enabled())
208 tracer_enabled = 1;
209 else
210 tracer_enabled = 0;
211
212 return ret;
213}
214
215static void stop_func_tracer(struct trace_array *tr, int graph)
216{
217 tracer_enabled = 0;
218
219 unregister_wakeup_function(tr, graph);
220}
221
222#ifdef CONFIG_FUNCTION_GRAPH_TRACER
223static int wakeup_display_graph(struct trace_array *tr, int set)
224{
225 if (!(is_graph(tr) ^ set))
226 return 0;
227
228 stop_func_tracer(tr, !set);
229
230 wakeup_reset(wakeup_trace);
231 tr->max_latency = 0;
232
233 return start_func_tracer(tr, set);
234}
235
236static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
237{
238 struct trace_array *tr = wakeup_trace;
239 struct trace_array_cpu *data;
240 unsigned long flags;
241 int pc, ret = 0;
242
243 if (ftrace_graph_ignore_func(trace))
244 return 0;
245 /*
246 * Do not trace a function if it's filtered by set_graph_notrace.
247 * Make the index of ret stack negative to indicate that it should
248 * ignore further functions. But it needs its own ret stack entry
249 * to recover the original index in order to continue tracing after
250 * returning from the function.
251 */
252 if (ftrace_graph_notrace_addr(trace->func))
253 return 1;
254
255 if (!func_prolog_preempt_disable(tr, &data, &pc))
256 return 0;
257
258 local_save_flags(flags);
259 ret = __trace_graph_entry(tr, trace, flags, pc);
260 atomic_dec(&data->disabled);
261 preempt_enable_notrace();
262
263 return ret;
264}
265
266static void wakeup_graph_return(struct ftrace_graph_ret *trace)
267{
268 struct trace_array *tr = wakeup_trace;
269 struct trace_array_cpu *data;
270 unsigned long flags;
271 int pc;
272
273 if (!func_prolog_preempt_disable(tr, &data, &pc))
274 return;
275
276 local_save_flags(flags);
277 __trace_graph_return(tr, trace, flags, pc);
278 atomic_dec(&data->disabled);
279
280 preempt_enable_notrace();
281 return;
282}
283
284static void wakeup_trace_open(struct trace_iterator *iter)
285{
286 if (is_graph(iter->tr))
287 graph_trace_open(iter);
288}
289
290static void wakeup_trace_close(struct trace_iterator *iter)
291{
292 if (iter->private)
293 graph_trace_close(iter);
294}
295
296#define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_PROC | \
297 TRACE_GRAPH_PRINT_ABS_TIME | \
298 TRACE_GRAPH_PRINT_DURATION)
299
300static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
301{
302 /*
303 * In graph mode call the graph tracer output function,
304 * otherwise go with the TRACE_FN event handler
305 */
306 if (is_graph(iter->tr))
307 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
308
309 return TRACE_TYPE_UNHANDLED;
310}
311
312static void wakeup_print_header(struct seq_file *s)
313{
314 if (is_graph(wakeup_trace))
315 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
316 else
317 trace_default_header(s);
318}
319
320static void
321__trace_function(struct trace_array *tr,
322 unsigned long ip, unsigned long parent_ip,
323 unsigned long flags, int pc)
324{
325 if (is_graph(tr))
326 trace_graph_function(tr, ip, parent_ip, flags, pc);
327 else
328 trace_function(tr, ip, parent_ip, flags, pc);
329}
330#else
331#define __trace_function trace_function
332
333static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
334{
335 return TRACE_TYPE_UNHANDLED;
336}
337
338static void wakeup_trace_open(struct trace_iterator *iter) { }
339static void wakeup_trace_close(struct trace_iterator *iter) { }
340
341#ifdef CONFIG_FUNCTION_TRACER
342static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
343{
344 return -1;
345}
346static void wakeup_graph_return(struct ftrace_graph_ret *trace) { }
347static void wakeup_print_header(struct seq_file *s)
348{
349 trace_default_header(s);
350}
351#else
352static void wakeup_print_header(struct seq_file *s)
353{
354 trace_latency_header(s);
355}
356#endif /* CONFIG_FUNCTION_TRACER */
357#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
358
359/*
360 * Should this new latency be reported/recorded?
361 */
362static bool report_latency(struct trace_array *tr, u64 delta)
363{
364 if (tracing_thresh) {
365 if (delta < tracing_thresh)
366 return false;
367 } else {
368 if (delta <= tr->max_latency)
369 return false;
370 }
371 return true;
372}
373
374static void
375probe_wakeup_migrate_task(void *ignore, struct task_struct *task, int cpu)
376{
377 if (task != wakeup_task)
378 return;
379
380 wakeup_current_cpu = cpu;
381}
382
383static void
384tracing_sched_switch_trace(struct trace_array *tr,
385 struct task_struct *prev,
386 struct task_struct *next,
387 unsigned long flags, int pc)
388{
389 struct trace_event_call *call = &event_context_switch;
390 struct ring_buffer *buffer = tr->trace_buffer.buffer;
391 struct ring_buffer_event *event;
392 struct ctx_switch_entry *entry;
393
394 event = trace_buffer_lock_reserve(buffer, TRACE_CTX,
395 sizeof(*entry), flags, pc);
396 if (!event)
397 return;
398 entry = ring_buffer_event_data(event);
399 entry->prev_pid = prev->pid;
400 entry->prev_prio = prev->prio;
401 entry->prev_state = task_state_index(prev);
402 entry->next_pid = next->pid;
403 entry->next_prio = next->prio;
404 entry->next_state = task_state_index(next);
405 entry->next_cpu = task_cpu(next);
406
407 if (!call_filter_check_discard(call, entry, buffer, event))
408 trace_buffer_unlock_commit(tr, buffer, event, flags, pc);
409}
410
411static void
412tracing_sched_wakeup_trace(struct trace_array *tr,
413 struct task_struct *wakee,
414 struct task_struct *curr,
415 unsigned long flags, int pc)
416{
417 struct trace_event_call *call = &event_wakeup;
418 struct ring_buffer_event *event;
419 struct ctx_switch_entry *entry;
420 struct ring_buffer *buffer = tr->trace_buffer.buffer;
421
422 event = trace_buffer_lock_reserve(buffer, TRACE_WAKE,
423 sizeof(*entry), flags, pc);
424 if (!event)
425 return;
426 entry = ring_buffer_event_data(event);
427 entry->prev_pid = curr->pid;
428 entry->prev_prio = curr->prio;
429 entry->prev_state = task_state_index(curr);
430 entry->next_pid = wakee->pid;
431 entry->next_prio = wakee->prio;
432 entry->next_state = task_state_index(wakee);
433 entry->next_cpu = task_cpu(wakee);
434
435 if (!call_filter_check_discard(call, entry, buffer, event))
436 trace_buffer_unlock_commit(tr, buffer, event, flags, pc);
437}
438
439static void notrace
440probe_wakeup_sched_switch(void *ignore, bool preempt,
441 struct task_struct *prev, struct task_struct *next)
442{
443 struct trace_array_cpu *data;
444 u64 T0, T1, delta;
445 unsigned long flags;
446 long disabled;
447 int cpu;
448 int pc;
449
450 tracing_record_cmdline(prev);
451
452 if (unlikely(!tracer_enabled))
453 return;
454
455 /*
456 * When we start a new trace, we set wakeup_task to NULL
457 * and then set tracer_enabled = 1. We want to make sure
458 * that another CPU does not see the tracer_enabled = 1
459 * and the wakeup_task with an older task, that might
460 * actually be the same as next.
461 */
462 smp_rmb();
463
464 if (next != wakeup_task)
465 return;
466
467 pc = preempt_count();
468
469 /* disable local data, not wakeup_cpu data */
470 cpu = raw_smp_processor_id();
471 disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
472 if (likely(disabled != 1))
473 goto out;
474
475 local_irq_save(flags);
476 arch_spin_lock(&wakeup_lock);
477
478 /* We could race with grabbing wakeup_lock */
479 if (unlikely(!tracer_enabled || next != wakeup_task))
480 goto out_unlock;
481
482 /* The task we are waiting for is waking up */
483 data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu);
484
485 __trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc);
486 tracing_sched_switch_trace(wakeup_trace, prev, next, flags, pc);
487
488 T0 = data->preempt_timestamp;
489 T1 = ftrace_now(cpu);
490 delta = T1-T0;
491
492 if (!report_latency(wakeup_trace, delta))
493 goto out_unlock;
494
495 if (likely(!is_tracing_stopped())) {
496 wakeup_trace->max_latency = delta;
497 update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu);
498 }
499
500out_unlock:
501 __wakeup_reset(wakeup_trace);
502 arch_spin_unlock(&wakeup_lock);
503 local_irq_restore(flags);
504out:
505 atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
506}
507
508static void __wakeup_reset(struct trace_array *tr)
509{
510 wakeup_cpu = -1;
511 wakeup_prio = -1;
512 tracing_dl = 0;
513
514 if (wakeup_task)
515 put_task_struct(wakeup_task);
516
517 wakeup_task = NULL;
518}
519
520static void wakeup_reset(struct trace_array *tr)
521{
522 unsigned long flags;
523
524 tracing_reset_online_cpus(&tr->trace_buffer);
525
526 local_irq_save(flags);
527 arch_spin_lock(&wakeup_lock);
528 __wakeup_reset(tr);
529 arch_spin_unlock(&wakeup_lock);
530 local_irq_restore(flags);
531}
532
533static void
534probe_wakeup(void *ignore, struct task_struct *p)
535{
536 struct trace_array_cpu *data;
537 int cpu = smp_processor_id();
538 unsigned long flags;
539 long disabled;
540 int pc;
541
542 if (likely(!tracer_enabled))
543 return;
544
545 tracing_record_cmdline(p);
546 tracing_record_cmdline(current);
547
548 /*
549 * Semantic is like this:
550 * - wakeup tracer handles all tasks in the system, independently
551 * from their scheduling class;
552 * - wakeup_rt tracer handles tasks belonging to sched_dl and
553 * sched_rt class;
554 * - wakeup_dl handles tasks belonging to sched_dl class only.
555 */
556 if (tracing_dl || (wakeup_dl && !dl_task(p)) ||
557 (wakeup_rt && !dl_task(p) && !rt_task(p)) ||
558 (!dl_task(p) && (p->prio >= wakeup_prio || p->prio >= current->prio)))
559 return;
560
561 pc = preempt_count();
562 disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
563 if (unlikely(disabled != 1))
564 goto out;
565
566 /* interrupts should be off from try_to_wake_up */
567 arch_spin_lock(&wakeup_lock);
568
569 /* check for races. */
570 if (!tracer_enabled || tracing_dl ||
571 (!dl_task(p) && p->prio >= wakeup_prio))
572 goto out_locked;
573
574 /* reset the trace */
575 __wakeup_reset(wakeup_trace);
576
577 wakeup_cpu = task_cpu(p);
578 wakeup_current_cpu = wakeup_cpu;
579 wakeup_prio = p->prio;
580
581 /*
582 * Once you start tracing a -deadline task, don't bother tracing
583 * another task until the first one wakes up.
584 */
585 if (dl_task(p))
586 tracing_dl = 1;
587 else
588 tracing_dl = 0;
589
590 wakeup_task = p;
591 get_task_struct(wakeup_task);
592
593 local_save_flags(flags);
594
595 data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu);
596 data->preempt_timestamp = ftrace_now(cpu);
597 tracing_sched_wakeup_trace(wakeup_trace, p, current, flags, pc);
598
599 /*
600 * We must be careful in using CALLER_ADDR2. But since wake_up
601 * is not called by an assembly function (where as schedule is)
602 * it should be safe to use it here.
603 */
604 __trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, flags, pc);
605
606out_locked:
607 arch_spin_unlock(&wakeup_lock);
608out:
609 atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
610}
611
612static void start_wakeup_tracer(struct trace_array *tr)
613{
614 int ret;
615
616 ret = register_trace_sched_wakeup(probe_wakeup, NULL);
617 if (ret) {
618 pr_info("wakeup trace: Couldn't activate tracepoint"
619 " probe to kernel_sched_wakeup\n");
620 return;
621 }
622
623 ret = register_trace_sched_wakeup_new(probe_wakeup, NULL);
624 if (ret) {
625 pr_info("wakeup trace: Couldn't activate tracepoint"
626 " probe to kernel_sched_wakeup_new\n");
627 goto fail_deprobe;
628 }
629
630 ret = register_trace_sched_switch(probe_wakeup_sched_switch, NULL);
631 if (ret) {
632 pr_info("sched trace: Couldn't activate tracepoint"
633 " probe to kernel_sched_switch\n");
634 goto fail_deprobe_wake_new;
635 }
636
637 ret = register_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
638 if (ret) {
639 pr_info("wakeup trace: Couldn't activate tracepoint"
640 " probe to kernel_sched_migrate_task\n");
641 return;
642 }
643
644 wakeup_reset(tr);
645
646 /*
647 * Don't let the tracer_enabled = 1 show up before
648 * the wakeup_task is reset. This may be overkill since
649 * wakeup_reset does a spin_unlock after setting the
650 * wakeup_task to NULL, but I want to be safe.
651 * This is a slow path anyway.
652 */
653 smp_wmb();
654
655 if (start_func_tracer(tr, is_graph(tr)))
656 printk(KERN_ERR "failed to start wakeup tracer\n");
657
658 return;
659fail_deprobe_wake_new:
660 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
661fail_deprobe:
662 unregister_trace_sched_wakeup(probe_wakeup, NULL);
663}
664
665static void stop_wakeup_tracer(struct trace_array *tr)
666{
667 tracer_enabled = 0;
668 stop_func_tracer(tr, is_graph(tr));
669 unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
670 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
671 unregister_trace_sched_wakeup(probe_wakeup, NULL);
672 unregister_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
673}
674
675static bool wakeup_busy;
676
677static int __wakeup_tracer_init(struct trace_array *tr)
678{
679 save_flags = tr->trace_flags;
680
681 /* non overwrite screws up the latency tracers */
682 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
683 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
684
685 tr->max_latency = 0;
686 wakeup_trace = tr;
687 ftrace_init_array_ops(tr, wakeup_tracer_call);
688 start_wakeup_tracer(tr);
689
690 wakeup_busy = true;
691 return 0;
692}
693
694static int wakeup_tracer_init(struct trace_array *tr)
695{
696 if (wakeup_busy)
697 return -EBUSY;
698
699 wakeup_dl = 0;
700 wakeup_rt = 0;
701 return __wakeup_tracer_init(tr);
702}
703
704static int wakeup_rt_tracer_init(struct trace_array *tr)
705{
706 if (wakeup_busy)
707 return -EBUSY;
708
709 wakeup_dl = 0;
710 wakeup_rt = 1;
711 return __wakeup_tracer_init(tr);
712}
713
714static int wakeup_dl_tracer_init(struct trace_array *tr)
715{
716 if (wakeup_busy)
717 return -EBUSY;
718
719 wakeup_dl = 1;
720 wakeup_rt = 0;
721 return __wakeup_tracer_init(tr);
722}
723
724static void wakeup_tracer_reset(struct trace_array *tr)
725{
726 int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
727 int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
728
729 stop_wakeup_tracer(tr);
730 /* make sure we put back any tasks we are tracing */
731 wakeup_reset(tr);
732
733 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
734 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
735 ftrace_reset_array_ops(tr);
736 wakeup_busy = false;
737}
738
739static void wakeup_tracer_start(struct trace_array *tr)
740{
741 wakeup_reset(tr);
742 tracer_enabled = 1;
743}
744
745static void wakeup_tracer_stop(struct trace_array *tr)
746{
747 tracer_enabled = 0;
748}
749
750static struct tracer wakeup_tracer __read_mostly =
751{
752 .name = "wakeup",
753 .init = wakeup_tracer_init,
754 .reset = wakeup_tracer_reset,
755 .start = wakeup_tracer_start,
756 .stop = wakeup_tracer_stop,
757 .print_max = true,
758 .print_header = wakeup_print_header,
759 .print_line = wakeup_print_line,
760 .flag_changed = wakeup_flag_changed,
761#ifdef CONFIG_FTRACE_SELFTEST
762 .selftest = trace_selftest_startup_wakeup,
763#endif
764 .open = wakeup_trace_open,
765 .close = wakeup_trace_close,
766 .allow_instances = true,
767 .use_max_tr = true,
768};
769
770static struct tracer wakeup_rt_tracer __read_mostly =
771{
772 .name = "wakeup_rt",
773 .init = wakeup_rt_tracer_init,
774 .reset = wakeup_tracer_reset,
775 .start = wakeup_tracer_start,
776 .stop = wakeup_tracer_stop,
777 .print_max = true,
778 .print_header = wakeup_print_header,
779 .print_line = wakeup_print_line,
780 .flag_changed = wakeup_flag_changed,
781#ifdef CONFIG_FTRACE_SELFTEST
782 .selftest = trace_selftest_startup_wakeup,
783#endif
784 .open = wakeup_trace_open,
785 .close = wakeup_trace_close,
786 .allow_instances = true,
787 .use_max_tr = true,
788};
789
790static struct tracer wakeup_dl_tracer __read_mostly =
791{
792 .name = "wakeup_dl",
793 .init = wakeup_dl_tracer_init,
794 .reset = wakeup_tracer_reset,
795 .start = wakeup_tracer_start,
796 .stop = wakeup_tracer_stop,
797 .print_max = true,
798 .print_header = wakeup_print_header,
799 .print_line = wakeup_print_line,
800 .flag_changed = wakeup_flag_changed,
801#ifdef CONFIG_FTRACE_SELFTEST
802 .selftest = trace_selftest_startup_wakeup,
803#endif
804 .open = wakeup_trace_open,
805 .close = wakeup_trace_close,
806 .allow_instances = true,
807 .use_max_tr = true,
808};
809
810__init static int init_wakeup_tracer(void)
811{
812 int ret;
813
814 ret = register_tracer(&wakeup_tracer);
815 if (ret)
816 return ret;
817
818 ret = register_tracer(&wakeup_rt_tracer);
819 if (ret)
820 return ret;
821
822 ret = register_tracer(&wakeup_dl_tracer);
823 if (ret)
824 return ret;
825
826 return 0;
827}
828core_initcall(init_wakeup_tracer);
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{
431 struct trace_array_cpu *data;
432 u64 T0, T1, delta;
433 unsigned long flags;
434 long disabled;
435 int cpu;
436 unsigned int trace_ctx;
437
438 tracing_record_cmdline(prev);
439
440 if (unlikely(!tracer_enabled))
441 return;
442
443 /*
444 * When we start a new trace, we set wakeup_task to NULL
445 * and then set tracer_enabled = 1. We want to make sure
446 * that another CPU does not see the tracer_enabled = 1
447 * and the wakeup_task with an older task, that might
448 * actually be the same as next.
449 */
450 smp_rmb();
451
452 if (next != wakeup_task)
453 return;
454
455 /* disable local data, not wakeup_cpu data */
456 cpu = raw_smp_processor_id();
457 disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
458 if (likely(disabled != 1))
459 goto out;
460
461 local_irq_save(flags);
462 trace_ctx = tracing_gen_ctx_flags(flags);
463
464 arch_spin_lock(&wakeup_lock);
465
466 /* We could race with grabbing wakeup_lock */
467 if (unlikely(!tracer_enabled || next != wakeup_task))
468 goto out_unlock;
469
470 /* The task we are waiting for is waking up */
471 data = per_cpu_ptr(wakeup_trace->array_buffer.data, wakeup_cpu);
472
473 __trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, trace_ctx);
474 tracing_sched_switch_trace(wakeup_trace, prev, next, trace_ctx);
475 __trace_stack(wakeup_trace, trace_ctx, 0);
476
477 T0 = data->preempt_timestamp;
478 T1 = ftrace_now(cpu);
479 delta = T1-T0;
480
481 if (!report_latency(wakeup_trace, delta))
482 goto out_unlock;
483
484 if (likely(!is_tracing_stopped())) {
485 wakeup_trace->max_latency = delta;
486 update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu, NULL);
487 }
488
489out_unlock:
490 __wakeup_reset(wakeup_trace);
491 arch_spin_unlock(&wakeup_lock);
492 local_irq_restore(flags);
493out:
494 atomic_dec(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
495}
496
497static void __wakeup_reset(struct trace_array *tr)
498{
499 wakeup_cpu = -1;
500 wakeup_prio = -1;
501 tracing_dl = false;
502
503 if (wakeup_task)
504 put_task_struct(wakeup_task);
505
506 wakeup_task = NULL;
507}
508
509static void wakeup_reset(struct trace_array *tr)
510{
511 unsigned long flags;
512
513 tracing_reset_online_cpus(&tr->array_buffer);
514
515 local_irq_save(flags);
516 arch_spin_lock(&wakeup_lock);
517 __wakeup_reset(tr);
518 arch_spin_unlock(&wakeup_lock);
519 local_irq_restore(flags);
520}
521
522static void
523probe_wakeup(void *ignore, struct task_struct *p)
524{
525 struct trace_array_cpu *data;
526 int cpu = smp_processor_id();
527 long disabled;
528 unsigned int trace_ctx;
529
530 if (likely(!tracer_enabled))
531 return;
532
533 tracing_record_cmdline(p);
534 tracing_record_cmdline(current);
535
536 /*
537 * Semantic is like this:
538 * - wakeup tracer handles all tasks in the system, independently
539 * from their scheduling class;
540 * - wakeup_rt tracer handles tasks belonging to sched_dl and
541 * sched_rt class;
542 * - wakeup_dl handles tasks belonging to sched_dl class only.
543 */
544 if (tracing_dl || (wakeup_dl && !dl_task(p)) ||
545 (wakeup_rt && !dl_task(p) && !rt_task(p)) ||
546 (!dl_task(p) && (p->prio >= wakeup_prio || p->prio >= current->prio)))
547 return;
548
549 disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
550 if (unlikely(disabled != 1))
551 goto out;
552
553 trace_ctx = tracing_gen_ctx();
554
555 /* interrupts should be off from try_to_wake_up */
556 arch_spin_lock(&wakeup_lock);
557
558 /* check for races. */
559 if (!tracer_enabled || tracing_dl ||
560 (!dl_task(p) && p->prio >= wakeup_prio))
561 goto out_locked;
562
563 /* reset the trace */
564 __wakeup_reset(wakeup_trace);
565
566 wakeup_cpu = task_cpu(p);
567 wakeup_current_cpu = wakeup_cpu;
568 wakeup_prio = p->prio;
569
570 /*
571 * Once you start tracing a -deadline task, don't bother tracing
572 * another task until the first one wakes up.
573 */
574 if (dl_task(p))
575 tracing_dl = true;
576 else
577 tracing_dl = false;
578
579 wakeup_task = get_task_struct(p);
580
581 data = per_cpu_ptr(wakeup_trace->array_buffer.data, wakeup_cpu);
582 data->preempt_timestamp = ftrace_now(cpu);
583 tracing_sched_wakeup_trace(wakeup_trace, p, current, trace_ctx);
584 __trace_stack(wakeup_trace, trace_ctx, 0);
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, trace_ctx);
592
593out_locked:
594 arch_spin_unlock(&wakeup_lock);
595out:
596 atomic_dec(&per_cpu_ptr(wakeup_trace->array_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 goto fail_deprobe_sched_switch;
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_sched_switch:
647 unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
648fail_deprobe_wake_new:
649 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
650fail_deprobe:
651 unregister_trace_sched_wakeup(probe_wakeup, NULL);
652}
653
654static void stop_wakeup_tracer(struct trace_array *tr)
655{
656 tracer_enabled = 0;
657 stop_func_tracer(tr, is_graph(tr));
658 unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
659 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
660 unregister_trace_sched_wakeup(probe_wakeup, NULL);
661 unregister_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
662}
663
664static bool wakeup_busy;
665
666static int __wakeup_tracer_init(struct trace_array *tr)
667{
668 save_flags = tr->trace_flags;
669
670 /* non overwrite screws up the latency tracers */
671 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
672 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
673
674 tr->max_latency = 0;
675 wakeup_trace = tr;
676 ftrace_init_array_ops(tr, wakeup_tracer_call);
677 start_wakeup_tracer(tr);
678
679 wakeup_busy = true;
680 return 0;
681}
682
683static int wakeup_tracer_init(struct trace_array *tr)
684{
685 if (wakeup_busy)
686 return -EBUSY;
687
688 wakeup_dl = false;
689 wakeup_rt = false;
690 return __wakeup_tracer_init(tr);
691}
692
693static int wakeup_rt_tracer_init(struct trace_array *tr)
694{
695 if (wakeup_busy)
696 return -EBUSY;
697
698 wakeup_dl = false;
699 wakeup_rt = true;
700 return __wakeup_tracer_init(tr);
701}
702
703static int wakeup_dl_tracer_init(struct trace_array *tr)
704{
705 if (wakeup_busy)
706 return -EBUSY;
707
708 wakeup_dl = true;
709 wakeup_rt = false;
710 return __wakeup_tracer_init(tr);
711}
712
713static void wakeup_tracer_reset(struct trace_array *tr)
714{
715 int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
716 int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
717
718 stop_wakeup_tracer(tr);
719 /* make sure we put back any tasks we are tracing */
720 wakeup_reset(tr);
721
722 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
723 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
724 ftrace_reset_array_ops(tr);
725 wakeup_busy = false;
726}
727
728static void wakeup_tracer_start(struct trace_array *tr)
729{
730 wakeup_reset(tr);
731 tracer_enabled = 1;
732}
733
734static void wakeup_tracer_stop(struct trace_array *tr)
735{
736 tracer_enabled = 0;
737}
738
739static struct tracer wakeup_tracer __read_mostly =
740{
741 .name = "wakeup",
742 .init = wakeup_tracer_init,
743 .reset = wakeup_tracer_reset,
744 .start = wakeup_tracer_start,
745 .stop = wakeup_tracer_stop,
746 .print_max = true,
747 .print_header = wakeup_print_header,
748 .print_line = wakeup_print_line,
749 .flag_changed = wakeup_flag_changed,
750#ifdef CONFIG_FTRACE_SELFTEST
751 .selftest = trace_selftest_startup_wakeup,
752#endif
753 .open = wakeup_trace_open,
754 .close = wakeup_trace_close,
755 .allow_instances = true,
756 .use_max_tr = true,
757};
758
759static struct tracer wakeup_rt_tracer __read_mostly =
760{
761 .name = "wakeup_rt",
762 .init = wakeup_rt_tracer_init,
763 .reset = wakeup_tracer_reset,
764 .start = wakeup_tracer_start,
765 .stop = wakeup_tracer_stop,
766 .print_max = true,
767 .print_header = wakeup_print_header,
768 .print_line = wakeup_print_line,
769 .flag_changed = wakeup_flag_changed,
770#ifdef CONFIG_FTRACE_SELFTEST
771 .selftest = trace_selftest_startup_wakeup,
772#endif
773 .open = wakeup_trace_open,
774 .close = wakeup_trace_close,
775 .allow_instances = true,
776 .use_max_tr = true,
777};
778
779static struct tracer wakeup_dl_tracer __read_mostly =
780{
781 .name = "wakeup_dl",
782 .init = wakeup_dl_tracer_init,
783 .reset = wakeup_tracer_reset,
784 .start = wakeup_tracer_start,
785 .stop = wakeup_tracer_stop,
786 .print_max = true,
787 .print_header = wakeup_print_header,
788 .print_line = wakeup_print_line,
789 .flag_changed = wakeup_flag_changed,
790#ifdef CONFIG_FTRACE_SELFTEST
791 .selftest = trace_selftest_startup_wakeup,
792#endif
793 .open = wakeup_trace_open,
794 .close = wakeup_trace_close,
795 .allow_instances = true,
796 .use_max_tr = true,
797};
798
799__init static int init_wakeup_tracer(void)
800{
801 int ret;
802
803 ret = register_tracer(&wakeup_tracer);
804 if (ret)
805 return ret;
806
807 ret = register_tracer(&wakeup_rt_tracer);
808 if (ret)
809 return ret;
810
811 ret = register_tracer(&wakeup_dl_tracer);
812 if (ret)
813 return ret;
814
815 return 0;
816}
817core_initcall(init_wakeup_tracer);