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TOMOYO Linux Cross Reference
Linux/kernel/trace/trace_sched_wakeup.c

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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 
 22 static struct trace_array       *wakeup_trace;
 23 static int __read_mostly        tracer_enabled;
 24 
 25 static struct task_struct       *wakeup_task;
 26 static int                      wakeup_cpu;
 27 static int                      wakeup_current_cpu;
 28 static unsigned                 wakeup_prio = -1;
 29 static int                      wakeup_rt;
 30 static int                      wakeup_dl;
 31 static int                      tracing_dl = 0;
 32 
 33 static arch_spinlock_t wakeup_lock =
 34         (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
 35 
 36 static void wakeup_reset(struct trace_array *tr);
 37 static void __wakeup_reset(struct trace_array *tr);
 38 static int start_func_tracer(struct trace_array *tr, int graph);
 39 static void stop_func_tracer(struct trace_array *tr, int graph);
 40 
 41 static int save_flags;
 42 
 43 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 44 # define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)
 45 #else
 46 # define is_graph(tr) false
 47 #endif
 48 
 49 #ifdef CONFIG_FUNCTION_TRACER
 50 
 51 static bool function_enabled;
 52 
 53 /*
 54  * Prologue for the wakeup function tracers.
 55  *
 56  * Returns 1 if it is OK to continue, and preemption
 57  *            is disabled and data->disabled is incremented.
 58  *         0 if the trace is to be ignored, and preemption
 59  *            is not disabled and data->disabled is
 60  *            kept the same.
 61  *
 62  * Note, this function is also used outside this ifdef but
 63  *  inside the #ifdef of the function graph tracer below.
 64  *  This is OK, since the function graph tracer is
 65  *  dependent on the function tracer.
 66  */
 67 static int
 68 func_prolog_preempt_disable(struct trace_array *tr,
 69                             struct trace_array_cpu **data,
 70                             int *pc)
 71 {
 72         long disabled;
 73         int cpu;
 74 
 75         if (likely(!wakeup_task))
 76                 return 0;
 77 
 78         *pc = preempt_count();
 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->trace_buffer.data, cpu);
 86         disabled = atomic_inc_return(&(*data)->disabled);
 87         if (unlikely(disabled != 1))
 88                 goto out;
 89 
 90         return 1;
 91 
 92 out:
 93         atomic_dec(&(*data)->disabled);
 94 
 95 out_enable:
 96         preempt_enable_notrace();
 97         return 0;
 98 }
 99 
100 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
101 
102 static int wakeup_display_graph(struct trace_array *tr, int set)
103 {
104         if (!(is_graph(tr) ^ set))
105                 return 0;
106 
107         stop_func_tracer(tr, !set);
108 
109         wakeup_reset(wakeup_trace);
110         tr->max_latency = 0;
111 
112         return start_func_tracer(tr, set);
113 }
114 
115 static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
116 {
117         struct trace_array *tr = wakeup_trace;
118         struct trace_array_cpu *data;
119         unsigned long flags;
120         int pc, 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, &pc))
135                 return 0;
136 
137         local_save_flags(flags);
138         ret = __trace_graph_entry(tr, trace, flags, pc);
139         atomic_dec(&data->disabled);
140         preempt_enable_notrace();
141 
142         return ret;
143 }
144 
145 static void wakeup_graph_return(struct ftrace_graph_ret *trace)
146 {
147         struct trace_array *tr = wakeup_trace;
148         struct trace_array_cpu *data;
149         unsigned long flags;
150         int pc;
151 
152         ftrace_graph_addr_finish(trace);
153 
154         if (!func_prolog_preempt_disable(tr, &data, &pc))
155                 return;
156 
157         local_save_flags(flags);
158         __trace_graph_return(tr, trace, flags, pc);
159         atomic_dec(&data->disabled);
160 
161         preempt_enable_notrace();
162         return;
163 }
164 
165 static struct fgraph_ops fgraph_wakeup_ops = {
166         .entryfunc = &wakeup_graph_entry,
167         .retfunc = &wakeup_graph_return,
168 };
169 
170 static void wakeup_trace_open(struct trace_iterator *iter)
171 {
172         if (is_graph(iter->tr))
173                 graph_trace_open(iter);
174 }
175 
176 static void wakeup_trace_close(struct trace_iterator *iter)
177 {
178         if (iter->private)
179                 graph_trace_close(iter);
180 }
181 
182 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_PROC | \
183                             TRACE_GRAPH_PRINT_ABS_TIME | \
184                             TRACE_GRAPH_PRINT_DURATION)
185 
186 static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
187 {
188         /*
189          * In graph mode call the graph tracer output function,
190          * otherwise go with the TRACE_FN event handler
191          */
192         if (is_graph(iter->tr))
193                 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
194 
195         return TRACE_TYPE_UNHANDLED;
196 }
197 
198 static void wakeup_print_header(struct seq_file *s)
199 {
200         if (is_graph(wakeup_trace))
201                 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
202         else
203                 trace_default_header(s);
204 }
205 #endif /* else CONFIG_FUNCTION_GRAPH_TRACER */
206 
207 /*
208  * wakeup uses its own tracer function to keep the overhead down:
209  */
210 static void
211 wakeup_tracer_call(unsigned long ip, unsigned long parent_ip,
212                    struct ftrace_ops *op, struct pt_regs *pt_regs)
213 {
214         struct trace_array *tr = wakeup_trace;
215         struct trace_array_cpu *data;
216         unsigned long flags;
217         int pc;
218 
219         if (!func_prolog_preempt_disable(tr, &data, &pc))
220                 return;
221 
222         local_irq_save(flags);
223         trace_function(tr, ip, parent_ip, flags, pc);
224         local_irq_restore(flags);
225 
226         atomic_dec(&data->disabled);
227         preempt_enable_notrace();
228 }
229 
230 static int register_wakeup_function(struct trace_array *tr, int graph, int set)
231 {
232         int ret;
233 
234         /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
235         if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
236                 return 0;
237 
238         if (graph)
239                 ret = register_ftrace_graph(&fgraph_wakeup_ops);
240         else
241                 ret = register_ftrace_function(tr->ops);
242 
243         if (!ret)
244                 function_enabled = true;
245 
246         return ret;
247 }
248 
249 static void unregister_wakeup_function(struct trace_array *tr, int graph)
250 {
251         if (!function_enabled)
252                 return;
253 
254         if (graph)
255                 unregister_ftrace_graph(&fgraph_wakeup_ops);
256         else
257                 unregister_ftrace_function(tr->ops);
258 
259         function_enabled = false;
260 }
261 
262 static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
263 {
264         if (!(mask & TRACE_ITER_FUNCTION))
265                 return 0;
266 
267         if (set)
268                 register_wakeup_function(tr, is_graph(tr), 1);
269         else
270                 unregister_wakeup_function(tr, is_graph(tr));
271         return 1;
272 }
273 #else /* CONFIG_FUNCTION_TRACER */
274 static int register_wakeup_function(struct trace_array *tr, int graph, int set)
275 {
276         return 0;
277 }
278 static void unregister_wakeup_function(struct trace_array *tr, int graph) { }
279 static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
280 {
281         return 0;
282 }
283 #endif /* else CONFIG_FUNCTION_TRACER */
284 
285 #ifndef CONFIG_FUNCTION_GRAPH_TRACER
286 static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
287 {
288         return TRACE_TYPE_UNHANDLED;
289 }
290 
291 static void wakeup_trace_open(struct trace_iterator *iter) { }
292 static void wakeup_trace_close(struct trace_iterator *iter) { }
293 
294 static void wakeup_print_header(struct seq_file *s)
295 {
296         trace_default_header(s);
297 }
298 #endif /* !CONFIG_FUNCTION_GRAPH_TRACER */
299 
300 static void
301 __trace_function(struct trace_array *tr,
302                  unsigned long ip, unsigned long parent_ip,
303                  unsigned long flags, int pc)
304 {
305         if (is_graph(tr))
306                 trace_graph_function(tr, ip, parent_ip, flags, pc);
307         else
308                 trace_function(tr, ip, parent_ip, flags, pc);
309 }
310 
311 static int wakeup_flag_changed(struct trace_array *tr, u32 mask, int set)
312 {
313         struct tracer *tracer = tr->current_trace;
314 
315         if (wakeup_function_set(tr, mask, set))
316                 return 0;
317 
318 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
319         if (mask & TRACE_ITER_DISPLAY_GRAPH)
320                 return wakeup_display_graph(tr, set);
321 #endif
322 
323         return trace_keep_overwrite(tracer, mask, set);
324 }
325 
326 static int start_func_tracer(struct trace_array *tr, int graph)
327 {
328         int ret;
329 
330         ret = register_wakeup_function(tr, graph, 0);
331 
332         if (!ret && tracing_is_enabled())
333                 tracer_enabled = 1;
334         else
335                 tracer_enabled = 0;
336 
337         return ret;
338 }
339 
340 static void stop_func_tracer(struct trace_array *tr, int graph)
341 {
342         tracer_enabled = 0;
343 
344         unregister_wakeup_function(tr, graph);
345 }
346 
347 /*
348  * Should this new latency be reported/recorded?
349  */
350 static bool report_latency(struct trace_array *tr, u64 delta)
351 {
352         if (tracing_thresh) {
353                 if (delta < tracing_thresh)
354                         return false;
355         } else {
356                 if (delta <= tr->max_latency)
357                         return false;
358         }
359         return true;
360 }
361 
362 static void
363 probe_wakeup_migrate_task(void *ignore, struct task_struct *task, int cpu)
364 {
365         if (task != wakeup_task)
366                 return;
367 
368         wakeup_current_cpu = cpu;
369 }
370 
371 static void
372 tracing_sched_switch_trace(struct trace_array *tr,
373                            struct task_struct *prev,
374                            struct task_struct *next,
375                            unsigned long flags, int pc)
376 {
377         struct trace_event_call *call = &event_context_switch;
378         struct ring_buffer *buffer = tr->trace_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), flags, pc);
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, flags, pc);
397 }
398 
399 static void
400 tracing_sched_wakeup_trace(struct trace_array *tr,
401                            struct task_struct *wakee,
402                            struct task_struct *curr,
403                            unsigned long flags, int pc)
404 {
405         struct trace_event_call *call = &event_wakeup;
406         struct ring_buffer_event *event;
407         struct ctx_switch_entry *entry;
408         struct ring_buffer *buffer = tr->trace_buffer.buffer;
409 
410         event = trace_buffer_lock_reserve(buffer, TRACE_WAKE,
411                                           sizeof(*entry), flags, pc);
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, flags, pc);
425 }
426 
427 static void notrace
428 probe_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         int pc;
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         pc = preempt_count();
456 
457         /* disable local data, not wakeup_cpu data */
458         cpu = raw_smp_processor_id();
459         disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
460         if (likely(disabled != 1))
461                 goto out;
462 
463         local_irq_save(flags);
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->trace_buffer.data, wakeup_cpu);
472 
473         __trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc);
474         tracing_sched_switch_trace(wakeup_trace, prev, next, flags, pc);
475 
476         T0 = data->preempt_timestamp;
477         T1 = ftrace_now(cpu);
478         delta = T1-T0;
479 
480         if (!report_latency(wakeup_trace, delta))
481                 goto out_unlock;
482 
483         if (likely(!is_tracing_stopped())) {
484                 wakeup_trace->max_latency = delta;
485                 update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu);
486         }
487 
488 out_unlock:
489         __wakeup_reset(wakeup_trace);
490         arch_spin_unlock(&wakeup_lock);
491         local_irq_restore(flags);
492 out:
493         atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
494 }
495 
496 static void __wakeup_reset(struct trace_array *tr)
497 {
498         wakeup_cpu = -1;
499         wakeup_prio = -1;
500         tracing_dl = 0;
501 
502         if (wakeup_task)
503                 put_task_struct(wakeup_task);
504 
505         wakeup_task = NULL;
506 }
507 
508 static void wakeup_reset(struct trace_array *tr)
509 {
510         unsigned long flags;
511 
512         tracing_reset_online_cpus(&tr->trace_buffer);
513 
514         local_irq_save(flags);
515         arch_spin_lock(&wakeup_lock);
516         __wakeup_reset(tr);
517         arch_spin_unlock(&wakeup_lock);
518         local_irq_restore(flags);
519 }
520 
521 static void
522 probe_wakeup(void *ignore, struct task_struct *p)
523 {
524         struct trace_array_cpu *data;
525         int cpu = smp_processor_id();
526         unsigned long flags;
527         long disabled;
528         int pc;
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         pc = preempt_count();
550         disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
551         if (unlikely(disabled != 1))
552                 goto out;
553 
554         /* interrupts should be off from try_to_wake_up */
555         arch_spin_lock(&wakeup_lock);
556 
557         /* check for races. */
558         if (!tracer_enabled || tracing_dl ||
559             (!dl_task(p) && p->prio >= wakeup_prio))
560                 goto out_locked;
561 
562         /* reset the trace */
563         __wakeup_reset(wakeup_trace);
564 
565         wakeup_cpu = task_cpu(p);
566         wakeup_current_cpu = wakeup_cpu;
567         wakeup_prio = p->prio;
568 
569         /*
570          * Once you start tracing a -deadline task, don't bother tracing
571          * another task until the first one wakes up.
572          */
573         if (dl_task(p))
574                 tracing_dl = 1;
575         else
576                 tracing_dl = 0;
577 
578         wakeup_task = p;
579         get_task_struct(wakeup_task);
580 
581         local_save_flags(flags);
582 
583         data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu);
584         data->preempt_timestamp = ftrace_now(cpu);
585         tracing_sched_wakeup_trace(wakeup_trace, p, current, flags, pc);
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, flags, pc);
593 
594 out_locked:
595         arch_spin_unlock(&wakeup_lock);
596 out:
597         atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
598 }
599 
600 static void start_wakeup_tracer(struct trace_array *tr)
601 {
602         int ret;
603 
604         ret = register_trace_sched_wakeup(probe_wakeup, NULL);
605         if (ret) {
606                 pr_info("wakeup trace: Couldn't activate tracepoint"
607                         " probe to kernel_sched_wakeup\n");
608                 return;
609         }
610 
611         ret = register_trace_sched_wakeup_new(probe_wakeup, NULL);
612         if (ret) {
613                 pr_info("wakeup trace: Couldn't activate tracepoint"
614                         " probe to kernel_sched_wakeup_new\n");
615                 goto fail_deprobe;
616         }
617 
618         ret = register_trace_sched_switch(probe_wakeup_sched_switch, NULL);
619         if (ret) {
620                 pr_info("sched trace: Couldn't activate tracepoint"
621                         " probe to kernel_sched_switch\n");
622                 goto fail_deprobe_wake_new;
623         }
624 
625         ret = register_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
626         if (ret) {
627                 pr_info("wakeup trace: Couldn't activate tracepoint"
628                         " probe to kernel_sched_migrate_task\n");
629                 return;
630         }
631 
632         wakeup_reset(tr);
633 
634         /*
635          * Don't let the tracer_enabled = 1 show up before
636          * the wakeup_task is reset. This may be overkill since
637          * wakeup_reset does a spin_unlock after setting the
638          * wakeup_task to NULL, but I want to be safe.
639          * This is a slow path anyway.
640          */
641         smp_wmb();
642 
643         if (start_func_tracer(tr, is_graph(tr)))
644                 printk(KERN_ERR "failed to start wakeup tracer\n");
645 
646         return;
647 fail_deprobe_wake_new:
648         unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
649 fail_deprobe:
650         unregister_trace_sched_wakeup(probe_wakeup, NULL);
651 }
652 
653 static void stop_wakeup_tracer(struct trace_array *tr)
654 {
655         tracer_enabled = 0;
656         stop_func_tracer(tr, is_graph(tr));
657         unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
658         unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
659         unregister_trace_sched_wakeup(probe_wakeup, NULL);
660         unregister_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
661 }
662 
663 static bool wakeup_busy;
664 
665 static int __wakeup_tracer_init(struct trace_array *tr)
666 {
667         save_flags = tr->trace_flags;
668 
669         /* non overwrite screws up the latency tracers */
670         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
671         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
672 
673         tr->max_latency = 0;
674         wakeup_trace = tr;
675         ftrace_init_array_ops(tr, wakeup_tracer_call);
676         start_wakeup_tracer(tr);
677 
678         wakeup_busy = true;
679         return 0;
680 }
681 
682 static int wakeup_tracer_init(struct trace_array *tr)
683 {
684         if (wakeup_busy)
685                 return -EBUSY;
686 
687         wakeup_dl = 0;
688         wakeup_rt = 0;
689         return __wakeup_tracer_init(tr);
690 }
691 
692 static int wakeup_rt_tracer_init(struct trace_array *tr)
693 {
694         if (wakeup_busy)
695                 return -EBUSY;
696 
697         wakeup_dl = 0;
698         wakeup_rt = 1;
699         return __wakeup_tracer_init(tr);
700 }
701 
702 static int wakeup_dl_tracer_init(struct trace_array *tr)
703 {
704         if (wakeup_busy)
705                 return -EBUSY;
706 
707         wakeup_dl = 1;
708         wakeup_rt = 0;
709         return __wakeup_tracer_init(tr);
710 }
711 
712 static void wakeup_tracer_reset(struct trace_array *tr)
713 {
714         int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
715         int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
716 
717         stop_wakeup_tracer(tr);
718         /* make sure we put back any tasks we are tracing */
719         wakeup_reset(tr);
720 
721         set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
722         set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
723         ftrace_reset_array_ops(tr);
724         wakeup_busy = false;
725 }
726 
727 static void wakeup_tracer_start(struct trace_array *tr)
728 {
729         wakeup_reset(tr);
730         tracer_enabled = 1;
731 }
732 
733 static void wakeup_tracer_stop(struct trace_array *tr)
734 {
735         tracer_enabled = 0;
736 }
737 
738 static struct tracer wakeup_tracer __read_mostly =
739 {
740         .name           = "wakeup",
741         .init           = wakeup_tracer_init,
742         .reset          = wakeup_tracer_reset,
743         .start          = wakeup_tracer_start,
744         .stop           = wakeup_tracer_stop,
745         .print_max      = true,
746         .print_header   = wakeup_print_header,
747         .print_line     = wakeup_print_line,
748         .flag_changed   = wakeup_flag_changed,
749 #ifdef CONFIG_FTRACE_SELFTEST
750         .selftest    = trace_selftest_startup_wakeup,
751 #endif
752         .open           = wakeup_trace_open,
753         .close          = wakeup_trace_close,
754         .allow_instances = true,
755         .use_max_tr     = true,
756 };
757 
758 static struct tracer wakeup_rt_tracer __read_mostly =
759 {
760         .name           = "wakeup_rt",
761         .init           = wakeup_rt_tracer_init,
762         .reset          = wakeup_tracer_reset,
763         .start          = wakeup_tracer_start,
764         .stop           = wakeup_tracer_stop,
765         .print_max      = true,
766         .print_header   = wakeup_print_header,
767         .print_line     = wakeup_print_line,
768         .flag_changed   = wakeup_flag_changed,
769 #ifdef CONFIG_FTRACE_SELFTEST
770         .selftest    = trace_selftest_startup_wakeup,
771 #endif
772         .open           = wakeup_trace_open,
773         .close          = wakeup_trace_close,
774         .allow_instances = true,
775         .use_max_tr     = true,
776 };
777 
778 static struct tracer wakeup_dl_tracer __read_mostly =
779 {
780         .name           = "wakeup_dl",
781         .init           = wakeup_dl_tracer_init,
782         .reset          = wakeup_tracer_reset,
783         .start          = wakeup_tracer_start,
784         .stop           = wakeup_tracer_stop,
785         .print_max      = true,
786         .print_header   = wakeup_print_header,
787         .print_line     = wakeup_print_line,
788         .flag_changed   = wakeup_flag_changed,
789 #ifdef CONFIG_FTRACE_SELFTEST
790         .selftest    = trace_selftest_startup_wakeup,
791 #endif
792         .open           = wakeup_trace_open,
793         .close          = wakeup_trace_close,
794         .allow_instances = true,
795         .use_max_tr     = true,
796 };
797 
798 __init static int init_wakeup_tracer(void)
799 {
800         int ret;
801 
802         ret = register_tracer(&wakeup_tracer);
803         if (ret)
804                 return ret;
805 
806         ret = register_tracer(&wakeup_rt_tracer);
807         if (ret)
808                 return ret;
809 
810         ret = register_tracer(&wakeup_dl_tracer);
811         if (ret)
812                 return ret;
813 
814         return 0;
815 }
816 core_initcall(init_wakeup_tracer);
817 

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