trace_sched_wakeup.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * trace task wakeup timings
  4 *
  5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
  6 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
  7 *
  8 * Based on code from the latency_tracer, that is:
  9 *
 10 *  Copyright (C) 2004-2006 Ingo Molnar
 11 *  Copyright (C) 2004 Nadia Yvette Chambers
 12 */
 13#include <linux/module.h>
 14#include <linux/kallsyms.h>
 15#include <linux/uaccess.h>
 16#include <linux/ftrace.h>
 17#include <linux/sched/rt.h>
 18#include <linux/sched/deadline.h>
 19#include <trace/events/sched.h>
 20#include "trace.h"
 21
 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 = local_inc_return(&(*data)->disabled);
 87	if (unlikely(disabled != 1))
 88		goto out;
 89
 90	return 1;
 91
 92out:
 93	local_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			      struct fgraph_ops *gops,
117			      struct ftrace_regs *fregs)
118{
119	struct trace_array *tr = wakeup_trace;
120	struct trace_array_cpu *data;
121	unsigned int trace_ctx;
122	u64 *calltime;
123	int ret = 0;
124
125	if (ftrace_graph_ignore_func(gops, trace))
126		return 0;
127	/*
128	 * Do not trace a function if it's filtered by set_graph_notrace.
129	 * Make the index of ret stack negative to indicate that it should
130	 * ignore further functions.  But it needs its own ret stack entry
131	 * to recover the original index in order to continue tracing after
132	 * returning from the function.
133	 */
134	if (ftrace_graph_notrace_addr(trace->func))
135		return 1;
136
137	if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
138		return 0;
139
140	calltime = fgraph_reserve_data(gops->idx, sizeof(*calltime));
141	if (calltime) {
142		*calltime = trace_clock_local();
143		ret = __trace_graph_entry(tr, trace, trace_ctx);
144	}
145	local_dec(&data->disabled);
146	preempt_enable_notrace();
147
148	return ret;
149}
150
151static void wakeup_graph_return(struct ftrace_graph_ret *trace,
152				struct fgraph_ops *gops,
153				struct ftrace_regs *fregs)
154{
155	struct trace_array *tr = wakeup_trace;
156	struct trace_array_cpu *data;
157	unsigned int trace_ctx;
158	u64 *calltime;
159	u64 rettime;
160	int size;
161
162	ftrace_graph_addr_finish(gops, trace);
163
164	if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
165		return;
166
167	rettime = trace_clock_local();
168
169	calltime = fgraph_retrieve_data(gops->idx, &size);
170	if (calltime)
171		__trace_graph_return(tr, trace, trace_ctx, *calltime, rettime);
172
173	local_dec(&data->disabled);
174	preempt_enable_notrace();
175	return;
176}
177
178static struct fgraph_ops fgraph_wakeup_ops = {
179	.entryfunc = &wakeup_graph_entry,
180	.retfunc = &wakeup_graph_return,
181};
182
183static void wakeup_trace_open(struct trace_iterator *iter)
184{
185	if (is_graph(iter->tr))
186		graph_trace_open(iter);
187}
188
189static void wakeup_trace_close(struct trace_iterator *iter)
190{
191	if (iter->private)
192		graph_trace_close(iter);
193}
194
195#define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_PROC | \
196			    TRACE_GRAPH_PRINT_CPU |  \
197			    TRACE_GRAPH_PRINT_REL_TIME | \
198			    TRACE_GRAPH_PRINT_DURATION | \
199			    TRACE_GRAPH_PRINT_OVERHEAD | \
200			    TRACE_GRAPH_PRINT_IRQS)
201
202static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
203{
204	/*
205	 * In graph mode call the graph tracer output function,
206	 * otherwise go with the TRACE_FN event handler
207	 */
208	if (is_graph(iter->tr))
209		return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
210
211	return TRACE_TYPE_UNHANDLED;
212}
213
214static void wakeup_print_header(struct seq_file *s)
215{
216	if (is_graph(wakeup_trace))
217		print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
218	else
219		trace_default_header(s);
220}
221#endif /* else CONFIG_FUNCTION_GRAPH_TRACER */
222
223/*
224 * wakeup uses its own tracer function to keep the overhead down:
225 */
226static void
227wakeup_tracer_call(unsigned long ip, unsigned long parent_ip,
228		   struct ftrace_ops *op, struct ftrace_regs *fregs)
229{
230	struct trace_array *tr = wakeup_trace;
231	struct trace_array_cpu *data;
232	unsigned long flags;
233	unsigned int trace_ctx;
234
235	if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
236		return;
237
238	local_irq_save(flags);
239	trace_function(tr, ip, parent_ip, trace_ctx, fregs);
240	local_irq_restore(flags);
241
242	local_dec(&data->disabled);
243	preempt_enable_notrace();
244}
245
246static int register_wakeup_function(struct trace_array *tr, int graph, int set)
247{
248	int ret;
249
250	/* 'set' is set if TRACE_ITER(FUNCTION) is about to be set */
251	if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER(FUNCTION))))
252		return 0;
253
254	if (graph)
255		ret = register_ftrace_graph(&fgraph_wakeup_ops);
256	else
257		ret = register_ftrace_function(tr->ops);
258
259	if (!ret)
260		function_enabled = true;
261
262	return ret;
263}
264
265static void unregister_wakeup_function(struct trace_array *tr, int graph)
266{
267	if (!function_enabled)
268		return;
269
270	if (graph)
271		unregister_ftrace_graph(&fgraph_wakeup_ops);
272	else
273		unregister_ftrace_function(tr->ops);
274
275	function_enabled = false;
276}
277
278static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
279{
280	if (!(mask & TRACE_ITER(FUNCTION)))
281		return 0;
282
283	if (set)
284		register_wakeup_function(tr, is_graph(tr), 1);
285	else
286		unregister_wakeup_function(tr, is_graph(tr));
287	return 1;
288}
289#else /* CONFIG_FUNCTION_TRACER */
290static int register_wakeup_function(struct trace_array *tr, int graph, int set)
291{
292	return 0;
293}
294static void unregister_wakeup_function(struct trace_array *tr, int graph) { }
295static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
296{
297	return 0;
298}
299#endif /* else CONFIG_FUNCTION_TRACER */
300
301#ifndef CONFIG_FUNCTION_GRAPH_TRACER
302static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
303{
304	return TRACE_TYPE_UNHANDLED;
305}
306
307static void wakeup_trace_open(struct trace_iterator *iter) { }
308static void wakeup_trace_close(struct trace_iterator *iter) { }
309
310static void wakeup_print_header(struct seq_file *s)
311{
312	trace_default_header(s);
313}
314#endif /* !CONFIG_FUNCTION_GRAPH_TRACER */
315
316static void
317__trace_function(struct trace_array *tr,
318		 unsigned long ip, unsigned long parent_ip,
319		 unsigned int trace_ctx)
320{
321	if (is_graph(tr))
322		trace_graph_function(tr, ip, parent_ip, trace_ctx);
323	else
324		trace_function(tr, ip, parent_ip, trace_ctx, NULL);
325}
326
327static int wakeup_flag_changed(struct trace_array *tr, u64 mask, int set)
328{
329	struct tracer *tracer = tr->current_trace;
330
331	if (wakeup_function_set(tr, mask, set))
332		return 0;
333
334#ifdef CONFIG_FUNCTION_GRAPH_TRACER
335	if (mask & TRACE_ITER(DISPLAY_GRAPH))
336		return wakeup_display_graph(tr, set);
337#endif
338
339	return trace_keep_overwrite(tracer, mask, set);
340}
341
342static int start_func_tracer(struct trace_array *tr, int graph)
343{
344	int ret;
345
346	ret = register_wakeup_function(tr, graph, 0);
347
348	if (!ret && tracing_is_enabled())
349		tracer_enabled = 1;
350	else
351		tracer_enabled = 0;
352
353	return ret;
354}
355
356static void stop_func_tracer(struct trace_array *tr, int graph)
357{
358	tracer_enabled = 0;
359
360	unregister_wakeup_function(tr, graph);
361}
362
363/*
364 * Should this new latency be reported/recorded?
365 */
366static bool report_latency(struct trace_array *tr, u64 delta)
367{
368	if (tracing_thresh) {
369		if (delta < tracing_thresh)
370			return false;
371	} else {
372		if (delta <= tr->max_latency)
373			return false;
374	}
375	return true;
376}
377
378static void
379probe_wakeup_migrate_task(void *ignore, struct task_struct *task, int cpu)
380{
381	if (task != wakeup_task)
382		return;
383
384	wakeup_current_cpu = cpu;
385}
386
387static void
388tracing_sched_switch_trace(struct trace_array *tr,
389			   struct task_struct *prev,
390			   struct task_struct *next,
391			   unsigned int trace_ctx)
392{
393	struct trace_buffer *buffer = tr->array_buffer.buffer;
394	struct ring_buffer_event *event;
395	struct ctx_switch_entry *entry;
396
397	event = trace_buffer_lock_reserve(buffer, TRACE_CTX,
398					  sizeof(*entry), trace_ctx);
399	if (!event)
400		return;
401	entry	= ring_buffer_event_data(event);
402	entry->prev_pid			= prev->pid;
403	entry->prev_prio		= prev->prio;
404	entry->prev_state		= task_state_index(prev);
405	entry->next_pid			= next->pid;
406	entry->next_prio		= next->prio;
407	entry->next_state		= task_state_index(next);
408	entry->next_cpu	= task_cpu(next);
409
410	trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
411}
412
413static void
414tracing_sched_wakeup_trace(struct trace_array *tr,
415			   struct task_struct *wakee,
416			   struct task_struct *curr,
417			   unsigned int trace_ctx)
418{
419	struct ring_buffer_event *event;
420	struct ctx_switch_entry *entry;
421	struct trace_buffer *buffer = tr->array_buffer.buffer;
422
423	event = trace_buffer_lock_reserve(buffer, TRACE_WAKE,
424					  sizeof(*entry), trace_ctx);
425	if (!event)
426		return;
427	entry	= ring_buffer_event_data(event);
428	entry->prev_pid			= curr->pid;
429	entry->prev_prio		= curr->prio;
430	entry->prev_state		= task_state_index(curr);
431	entry->next_pid			= wakee->pid;
432	entry->next_prio		= wakee->prio;
433	entry->next_state		= task_state_index(wakee);
434	entry->next_cpu			= task_cpu(wakee);
435
436	trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
437}
438
439static void notrace
440probe_wakeup_sched_switch(void *ignore, bool preempt,
441			  struct task_struct *prev, struct task_struct *next,
442			  unsigned int prev_state)
443{
444	struct trace_array_cpu *data;
445	u64 T0, T1, delta;
446	unsigned long flags;
447	long disabled;
448	int cpu;
449	unsigned int trace_ctx;
450
451	tracing_record_cmdline(prev);
452
453	if (unlikely(!tracer_enabled))
454		return;
455
456	/*
457	 * When we start a new trace, we set wakeup_task to NULL
458	 * and then set tracer_enabled = 1. We want to make sure
459	 * that another CPU does not see the tracer_enabled = 1
460	 * and the wakeup_task with an older task, that might
461	 * actually be the same as next.
462	 */
463	smp_rmb();
464
465	if (next != wakeup_task)
466		return;
467
468	/* disable local data, not wakeup_cpu data */
469	cpu = raw_smp_processor_id();
470	disabled = local_inc_return(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
471	if (likely(disabled != 1))
472		goto out;
473
474	local_irq_save(flags);
475	trace_ctx = tracing_gen_ctx_flags(flags);
476
477	arch_spin_lock(&wakeup_lock);
478
479	/* We could race with grabbing wakeup_lock */
480	if (unlikely(!tracer_enabled || next != wakeup_task))
481		goto out_unlock;
482
483	/* The task we are waiting for is waking up */
484	data = per_cpu_ptr(wakeup_trace->array_buffer.data, wakeup_cpu);
485
486	__trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, trace_ctx);
487	tracing_sched_switch_trace(wakeup_trace, prev, next, trace_ctx);
488	__trace_stack(wakeup_trace, trace_ctx, 0);
489
490	T0 = data->preempt_timestamp;
491	T1 = ftrace_now(cpu);
492	delta = T1-T0;
493
494	if (!report_latency(wakeup_trace, delta))
495		goto out_unlock;
496
497	if (likely(!is_tracing_stopped())) {
498		wakeup_trace->max_latency = delta;
499		update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu, NULL);
500	}
501
502out_unlock:
503	__wakeup_reset(wakeup_trace);
504	arch_spin_unlock(&wakeup_lock);
505	local_irq_restore(flags);
506out:
507	local_dec(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
508}
509
510static void __wakeup_reset(struct trace_array *tr)
511{
512	wakeup_cpu = -1;
513	wakeup_prio = -1;
514	tracing_dl = false;
515
516	if (wakeup_task)
517		put_task_struct(wakeup_task);
518
519	wakeup_task = NULL;
520}
521
522static void wakeup_reset(struct trace_array *tr)
523{
524	unsigned long flags;
525
526	tracing_reset_online_cpus(&tr->array_buffer);
527
528	local_irq_save(flags);
529	arch_spin_lock(&wakeup_lock);
530	__wakeup_reset(tr);
531	arch_spin_unlock(&wakeup_lock);
532	local_irq_restore(flags);
533}
534
535static void
536probe_wakeup(void *ignore, struct task_struct *p)
537{
538	struct trace_array_cpu *data;
539	int cpu = smp_processor_id();
540	long disabled;
541	unsigned int trace_ctx;
542
543	if (likely(!tracer_enabled))
544		return;
545
546	tracing_record_cmdline(p);
547	tracing_record_cmdline(current);
548
549	/*
550	 * Semantic is like this:
551	 *  - wakeup tracer handles all tasks in the system, independently
552	 *    from their scheduling class;
553	 *  - wakeup_rt tracer handles tasks belonging to sched_dl and
554	 *    sched_rt class;
555	 *  - wakeup_dl handles tasks belonging to sched_dl class only.
556	 */
557	if (tracing_dl || (wakeup_dl && !dl_task(p)) ||
558	    (wakeup_rt && !rt_or_dl_task(p)) ||
559	    (!dl_task(p) && (p->prio >= wakeup_prio || p->prio >= current->prio)))
560		return;
561
562	disabled = local_inc_return(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
563	if (unlikely(disabled != 1))
564		goto out;
565
566	trace_ctx = tracing_gen_ctx();
567
568	/* interrupts should be off from try_to_wake_up */
569	arch_spin_lock(&wakeup_lock);
570
571	/* check for races. */
572	if (!tracer_enabled || tracing_dl ||
573	    (!dl_task(p) && p->prio >= wakeup_prio))
574		goto out_locked;
575
576	/* reset the trace */
577	__wakeup_reset(wakeup_trace);
578
579	wakeup_cpu = task_cpu(p);
580	wakeup_current_cpu = wakeup_cpu;
581	wakeup_prio = p->prio;
582
583	/*
584	 * Once you start tracing a -deadline task, don't bother tracing
585	 * another task until the first one wakes up.
586	 */
587	if (dl_task(p))
588		tracing_dl = true;
589	else
590		tracing_dl = false;
591
592	wakeup_task = get_task_struct(p);
593
594	data = per_cpu_ptr(wakeup_trace->array_buffer.data, wakeup_cpu);
595	data->preempt_timestamp = ftrace_now(cpu);
596	tracing_sched_wakeup_trace(wakeup_trace, p, current, trace_ctx);
597	__trace_stack(wakeup_trace, trace_ctx, 0);
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, trace_ctx);
605
606out_locked:
607	arch_spin_unlock(&wakeup_lock);
608out:
609	local_dec(&per_cpu_ptr(wakeup_trace->array_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		goto fail_deprobe_sched_switch;
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_sched_switch:
660	unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
661fail_deprobe_wake_new:
662	unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
663fail_deprobe:
664	unregister_trace_sched_wakeup(probe_wakeup, NULL);
665}
666
667static void stop_wakeup_tracer(struct trace_array *tr)
668{
669	tracer_enabled = 0;
670	stop_func_tracer(tr, is_graph(tr));
671	unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
672	unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
673	unregister_trace_sched_wakeup(probe_wakeup, NULL);
674	unregister_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
675}
676
677static bool wakeup_busy;
678
679static int __wakeup_tracer_init(struct trace_array *tr)
680{
681	save_flags = tr->trace_flags;
682
683	/* non overwrite screws up the latency tracers */
684	set_tracer_flag(tr, TRACE_ITER(OVERWRITE), 1);
685	set_tracer_flag(tr, TRACE_ITER(LATENCY_FMT), 1);
686
687	tr->max_latency = 0;
688	wakeup_trace = tr;
689	ftrace_init_array_ops(tr, wakeup_tracer_call);
690	start_wakeup_tracer(tr);
691
692	wakeup_busy = true;
693	return 0;
694}
695
696static int wakeup_tracer_init(struct trace_array *tr)
697{
698	if (wakeup_busy)
699		return -EBUSY;
700
701	wakeup_dl = false;
702	wakeup_rt = false;
703	return __wakeup_tracer_init(tr);
704}
705
706static int wakeup_rt_tracer_init(struct trace_array *tr)
707{
708	if (wakeup_busy)
709		return -EBUSY;
710
711	wakeup_dl = false;
712	wakeup_rt = true;
713	return __wakeup_tracer_init(tr);
714}
715
716static int wakeup_dl_tracer_init(struct trace_array *tr)
717{
718	if (wakeup_busy)
719		return -EBUSY;
720
721	wakeup_dl = true;
722	wakeup_rt = false;
723	return __wakeup_tracer_init(tr);
724}
725
726static void wakeup_tracer_reset(struct trace_array *tr)
727{
728	int lat_flag = save_flags & TRACE_ITER(LATENCY_FMT);
729	int overwrite_flag = save_flags & TRACE_ITER(OVERWRITE);
730
731	stop_wakeup_tracer(tr);
732	/* make sure we put back any tasks we are tracing */
733	wakeup_reset(tr);
734
735	set_tracer_flag(tr, TRACE_ITER(LATENCY_FMT), lat_flag);
736	set_tracer_flag(tr, TRACE_ITER(OVERWRITE), overwrite_flag);
737	ftrace_reset_array_ops(tr);
738	wakeup_busy = false;
739}
740
741static void wakeup_tracer_start(struct trace_array *tr)
742{
743	wakeup_reset(tr);
744	tracer_enabled = 1;
745}
746
747static void wakeup_tracer_stop(struct trace_array *tr)
748{
749	tracer_enabled = 0;
750}
751
752static struct tracer wakeup_tracer __read_mostly =
753{
754	.name		= "wakeup",
755	.init		= wakeup_tracer_init,
756	.reset		= wakeup_tracer_reset,
757	.start		= wakeup_tracer_start,
758	.stop		= wakeup_tracer_stop,
759	.print_max	= true,
760	.print_header	= wakeup_print_header,
761	.print_line	= wakeup_print_line,
762	.flag_changed	= wakeup_flag_changed,
763#ifdef CONFIG_FTRACE_SELFTEST
764	.selftest    = trace_selftest_startup_wakeup,
765#endif
766	.open		= wakeup_trace_open,
767	.close		= wakeup_trace_close,
768	.allow_instances = true,
769	.use_max_tr	= true,
770};
771
772static struct tracer wakeup_rt_tracer __read_mostly =
773{
774	.name		= "wakeup_rt",
775	.init		= wakeup_rt_tracer_init,
776	.reset		= wakeup_tracer_reset,
777	.start		= wakeup_tracer_start,
778	.stop		= wakeup_tracer_stop,
779	.print_max	= true,
780	.print_header	= wakeup_print_header,
781	.print_line	= wakeup_print_line,
782	.flag_changed	= wakeup_flag_changed,
783#ifdef CONFIG_FTRACE_SELFTEST
784	.selftest    = trace_selftest_startup_wakeup,
785#endif
786	.open		= wakeup_trace_open,
787	.close		= wakeup_trace_close,
788	.allow_instances = true,
789	.use_max_tr	= true,
790};
791
792static struct tracer wakeup_dl_tracer __read_mostly =
793{
794	.name		= "wakeup_dl",
795	.init		= wakeup_dl_tracer_init,
796	.reset		= wakeup_tracer_reset,
797	.start		= wakeup_tracer_start,
798	.stop		= wakeup_tracer_stop,
799	.print_max	= true,
800	.print_header	= wakeup_print_header,
801	.print_line	= wakeup_print_line,
802	.flag_changed	= wakeup_flag_changed,
803#ifdef CONFIG_FTRACE_SELFTEST
804	.selftest    = trace_selftest_startup_wakeup,
805#endif
806	.open		= wakeup_trace_open,
807	.close		= wakeup_trace_close,
808	.allow_instances = true,
809	.use_max_tr	= true,
810};
811
812__init static int init_wakeup_tracer(void)
813{
814	int ret;
815
816	ret = register_tracer(&wakeup_tracer);
817	if (ret)
818		return ret;
819
820	ret = register_tracer(&wakeup_rt_tracer);
821	if (ret)
822		return ret;
823
824	ret = register_tracer(&wakeup_dl_tracer);
825	if (ret)
826		return ret;
827
828	return 0;
829}
830core_initcall(init_wakeup_tracer);