drbd: merge_bvec_fn: properly remap bvm->bi_bdev
[linux/fpc-iii.git] / kernel / trace / trace_sched_wakeup.c
blob6e32635e5e570c7632aaebeb724c1d34e10172a1
1 /*
2 * trace task wakeup timings
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 * Based on code from the latency_tracer, that is:
9 * Copyright (C) 2004-2006 Ingo Molnar
10 * Copyright (C) 2004 Nadia Yvette Chambers
12 #include <linux/module.h>
13 #include <linux/fs.h>
14 #include <linux/debugfs.h>
15 #include <linux/kallsyms.h>
16 #include <linux/uaccess.h>
17 #include <linux/ftrace.h>
18 #include <linux/sched/rt.h>
19 #include <linux/sched/deadline.h>
20 #include <trace/events/sched.h>
21 #include "trace.h"
23 static struct trace_array *wakeup_trace;
24 static int __read_mostly tracer_enabled;
26 static struct task_struct *wakeup_task;
27 static int wakeup_cpu;
28 static int wakeup_current_cpu;
29 static unsigned wakeup_prio = -1;
30 static int wakeup_rt;
31 static int wakeup_dl;
32 static int tracing_dl = 0;
34 static arch_spinlock_t wakeup_lock =
35 (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
37 static void wakeup_reset(struct trace_array *tr);
38 static void __wakeup_reset(struct trace_array *tr);
39 static int wakeup_graph_entry(struct ftrace_graph_ent *trace);
40 static void wakeup_graph_return(struct ftrace_graph_ret *trace);
42 static int save_flags;
43 static bool function_enabled;
45 #define TRACE_DISPLAY_GRAPH 1
47 static struct tracer_opt trace_opts[] = {
48 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
49 /* display latency trace as call graph */
50 { TRACER_OPT(display-graph, TRACE_DISPLAY_GRAPH) },
51 #endif
52 { } /* Empty entry */
55 static struct tracer_flags tracer_flags = {
56 .val = 0,
57 .opts = trace_opts,
60 #define is_graph() (tracer_flags.val & TRACE_DISPLAY_GRAPH)
62 #ifdef CONFIG_FUNCTION_TRACER
65 * Prologue for the wakeup function tracers.
67 * Returns 1 if it is OK to continue, and preemption
68 * is disabled and data->disabled is incremented.
69 * 0 if the trace is to be ignored, and preemption
70 * is not disabled and data->disabled is
71 * kept the same.
73 * Note, this function is also used outside this ifdef but
74 * inside the #ifdef of the function graph tracer below.
75 * This is OK, since the function graph tracer is
76 * dependent on the function tracer.
78 static int
79 func_prolog_preempt_disable(struct trace_array *tr,
80 struct trace_array_cpu **data,
81 int *pc)
83 long disabled;
84 int cpu;
86 if (likely(!wakeup_task))
87 return 0;
89 *pc = preempt_count();
90 preempt_disable_notrace();
92 cpu = raw_smp_processor_id();
93 if (cpu != wakeup_current_cpu)
94 goto out_enable;
96 *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
97 disabled = atomic_inc_return(&(*data)->disabled);
98 if (unlikely(disabled != 1))
99 goto out;
101 return 1;
103 out:
104 atomic_dec(&(*data)->disabled);
106 out_enable:
107 preempt_enable_notrace();
108 return 0;
112 * wakeup uses its own tracer function to keep the overhead down:
114 static void
115 wakeup_tracer_call(unsigned long ip, unsigned long parent_ip,
116 struct ftrace_ops *op, struct pt_regs *pt_regs)
118 struct trace_array *tr = wakeup_trace;
119 struct trace_array_cpu *data;
120 unsigned long flags;
121 int pc;
123 if (!func_prolog_preempt_disable(tr, &data, &pc))
124 return;
126 local_irq_save(flags);
127 trace_function(tr, ip, parent_ip, flags, pc);
128 local_irq_restore(flags);
130 atomic_dec(&data->disabled);
131 preempt_enable_notrace();
134 static struct ftrace_ops trace_ops __read_mostly =
136 .func = wakeup_tracer_call,
137 .flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE,
139 #endif /* CONFIG_FUNCTION_TRACER */
141 static int register_wakeup_function(int graph, int set)
143 int ret;
145 /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
146 if (function_enabled || (!set && !(trace_flags & TRACE_ITER_FUNCTION)))
147 return 0;
149 if (graph)
150 ret = register_ftrace_graph(&wakeup_graph_return,
151 &wakeup_graph_entry);
152 else
153 ret = register_ftrace_function(&trace_ops);
155 if (!ret)
156 function_enabled = true;
158 return ret;
161 static void unregister_wakeup_function(int graph)
163 if (!function_enabled)
164 return;
166 if (graph)
167 unregister_ftrace_graph();
168 else
169 unregister_ftrace_function(&trace_ops);
171 function_enabled = false;
174 static void wakeup_function_set(int set)
176 if (set)
177 register_wakeup_function(is_graph(), 1);
178 else
179 unregister_wakeup_function(is_graph());
182 static int wakeup_flag_changed(struct tracer *tracer, u32 mask, int set)
184 if (mask & TRACE_ITER_FUNCTION)
185 wakeup_function_set(set);
187 return trace_keep_overwrite(tracer, mask, set);
190 static int start_func_tracer(int graph)
192 int ret;
194 ret = register_wakeup_function(graph, 0);
196 if (!ret && tracing_is_enabled())
197 tracer_enabled = 1;
198 else
199 tracer_enabled = 0;
201 return ret;
204 static void stop_func_tracer(int graph)
206 tracer_enabled = 0;
208 unregister_wakeup_function(graph);
211 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
212 static int wakeup_set_flag(u32 old_flags, u32 bit, int set)
215 if (!(bit & TRACE_DISPLAY_GRAPH))
216 return -EINVAL;
218 if (!(is_graph() ^ set))
219 return 0;
221 stop_func_tracer(!set);
223 wakeup_reset(wakeup_trace);
224 tracing_max_latency = 0;
226 return start_func_tracer(set);
229 static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
231 struct trace_array *tr = wakeup_trace;
232 struct trace_array_cpu *data;
233 unsigned long flags;
234 int pc, ret = 0;
236 if (!func_prolog_preempt_disable(tr, &data, &pc))
237 return 0;
239 local_save_flags(flags);
240 ret = __trace_graph_entry(tr, trace, flags, pc);
241 atomic_dec(&data->disabled);
242 preempt_enable_notrace();
244 return ret;
247 static void wakeup_graph_return(struct ftrace_graph_ret *trace)
249 struct trace_array *tr = wakeup_trace;
250 struct trace_array_cpu *data;
251 unsigned long flags;
252 int pc;
254 if (!func_prolog_preempt_disable(tr, &data, &pc))
255 return;
257 local_save_flags(flags);
258 __trace_graph_return(tr, trace, flags, pc);
259 atomic_dec(&data->disabled);
261 preempt_enable_notrace();
262 return;
265 static void wakeup_trace_open(struct trace_iterator *iter)
267 if (is_graph())
268 graph_trace_open(iter);
271 static void wakeup_trace_close(struct trace_iterator *iter)
273 if (iter->private)
274 graph_trace_close(iter);
277 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_PROC | \
278 TRACE_GRAPH_PRINT_ABS_TIME | \
279 TRACE_GRAPH_PRINT_DURATION)
281 static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
284 * In graph mode call the graph tracer output function,
285 * otherwise go with the TRACE_FN event handler
287 if (is_graph())
288 return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
290 return TRACE_TYPE_UNHANDLED;
293 static void wakeup_print_header(struct seq_file *s)
295 if (is_graph())
296 print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
297 else
298 trace_default_header(s);
301 static void
302 __trace_function(struct trace_array *tr,
303 unsigned long ip, unsigned long parent_ip,
304 unsigned long flags, int pc)
306 if (is_graph())
307 trace_graph_function(tr, ip, parent_ip, flags, pc);
308 else
309 trace_function(tr, ip, parent_ip, flags, pc);
311 #else
312 #define __trace_function trace_function
314 static int wakeup_set_flag(u32 old_flags, u32 bit, int set)
316 return -EINVAL;
319 static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
321 return -1;
324 static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
326 return TRACE_TYPE_UNHANDLED;
329 static void wakeup_graph_return(struct ftrace_graph_ret *trace) { }
330 static void wakeup_trace_open(struct trace_iterator *iter) { }
331 static void wakeup_trace_close(struct trace_iterator *iter) { }
333 #ifdef CONFIG_FUNCTION_TRACER
334 static void wakeup_print_header(struct seq_file *s)
336 trace_default_header(s);
338 #else
339 static void wakeup_print_header(struct seq_file *s)
341 trace_latency_header(s);
343 #endif /* CONFIG_FUNCTION_TRACER */
344 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
347 * Should this new latency be reported/recorded?
349 static int report_latency(cycle_t delta)
351 if (tracing_thresh) {
352 if (delta < tracing_thresh)
353 return 0;
354 } else {
355 if (delta <= tracing_max_latency)
356 return 0;
358 return 1;
361 static void
362 probe_wakeup_migrate_task(void *ignore, struct task_struct *task, int cpu)
364 if (task != wakeup_task)
365 return;
367 wakeup_current_cpu = cpu;
370 static void notrace
371 probe_wakeup_sched_switch(void *ignore,
372 struct task_struct *prev, struct task_struct *next)
374 struct trace_array_cpu *data;
375 cycle_t T0, T1, delta;
376 unsigned long flags;
377 long disabled;
378 int cpu;
379 int pc;
381 tracing_record_cmdline(prev);
383 if (unlikely(!tracer_enabled))
384 return;
387 * When we start a new trace, we set wakeup_task to NULL
388 * and then set tracer_enabled = 1. We want to make sure
389 * that another CPU does not see the tracer_enabled = 1
390 * and the wakeup_task with an older task, that might
391 * actually be the same as next.
393 smp_rmb();
395 if (next != wakeup_task)
396 return;
398 pc = preempt_count();
400 /* disable local data, not wakeup_cpu data */
401 cpu = raw_smp_processor_id();
402 disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
403 if (likely(disabled != 1))
404 goto out;
406 local_irq_save(flags);
407 arch_spin_lock(&wakeup_lock);
409 /* We could race with grabbing wakeup_lock */
410 if (unlikely(!tracer_enabled || next != wakeup_task))
411 goto out_unlock;
413 /* The task we are waiting for is waking up */
414 data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu);
416 __trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc);
417 tracing_sched_switch_trace(wakeup_trace, prev, next, flags, pc);
419 T0 = data->preempt_timestamp;
420 T1 = ftrace_now(cpu);
421 delta = T1-T0;
423 if (!report_latency(delta))
424 goto out_unlock;
426 if (likely(!is_tracing_stopped())) {
427 tracing_max_latency = delta;
428 update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu);
431 out_unlock:
432 __wakeup_reset(wakeup_trace);
433 arch_spin_unlock(&wakeup_lock);
434 local_irq_restore(flags);
435 out:
436 atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
439 static void __wakeup_reset(struct trace_array *tr)
441 wakeup_cpu = -1;
442 wakeup_prio = -1;
443 tracing_dl = 0;
445 if (wakeup_task)
446 put_task_struct(wakeup_task);
448 wakeup_task = NULL;
451 static void wakeup_reset(struct trace_array *tr)
453 unsigned long flags;
455 tracing_reset_online_cpus(&tr->trace_buffer);
457 local_irq_save(flags);
458 arch_spin_lock(&wakeup_lock);
459 __wakeup_reset(tr);
460 arch_spin_unlock(&wakeup_lock);
461 local_irq_restore(flags);
464 static void
465 probe_wakeup(void *ignore, struct task_struct *p, int success)
467 struct trace_array_cpu *data;
468 int cpu = smp_processor_id();
469 unsigned long flags;
470 long disabled;
471 int pc;
473 if (likely(!tracer_enabled))
474 return;
476 tracing_record_cmdline(p);
477 tracing_record_cmdline(current);
480 * Semantic is like this:
481 * - wakeup tracer handles all tasks in the system, independently
482 * from their scheduling class;
483 * - wakeup_rt tracer handles tasks belonging to sched_dl and
484 * sched_rt class;
485 * - wakeup_dl handles tasks belonging to sched_dl class only.
487 if (tracing_dl || (wakeup_dl && !dl_task(p)) ||
488 (wakeup_rt && !dl_task(p) && !rt_task(p)) ||
489 (!dl_task(p) && (p->prio >= wakeup_prio || p->prio >= current->prio)))
490 return;
492 pc = preempt_count();
493 disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
494 if (unlikely(disabled != 1))
495 goto out;
497 /* interrupts should be off from try_to_wake_up */
498 arch_spin_lock(&wakeup_lock);
500 /* check for races. */
501 if (!tracer_enabled || tracing_dl ||
502 (!dl_task(p) && p->prio >= wakeup_prio))
503 goto out_locked;
505 /* reset the trace */
506 __wakeup_reset(wakeup_trace);
508 wakeup_cpu = task_cpu(p);
509 wakeup_current_cpu = wakeup_cpu;
510 wakeup_prio = p->prio;
513 * Once you start tracing a -deadline task, don't bother tracing
514 * another task until the first one wakes up.
516 if (dl_task(p))
517 tracing_dl = 1;
518 else
519 tracing_dl = 0;
521 wakeup_task = p;
522 get_task_struct(wakeup_task);
524 local_save_flags(flags);
526 data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu);
527 data->preempt_timestamp = ftrace_now(cpu);
528 tracing_sched_wakeup_trace(wakeup_trace, p, current, flags, pc);
531 * We must be careful in using CALLER_ADDR2. But since wake_up
532 * is not called by an assembly function (where as schedule is)
533 * it should be safe to use it here.
535 __trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, flags, pc);
537 out_locked:
538 arch_spin_unlock(&wakeup_lock);
539 out:
540 atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled);
543 static void start_wakeup_tracer(struct trace_array *tr)
545 int ret;
547 ret = register_trace_sched_wakeup(probe_wakeup, NULL);
548 if (ret) {
549 pr_info("wakeup trace: Couldn't activate tracepoint"
550 " probe to kernel_sched_wakeup\n");
551 return;
554 ret = register_trace_sched_wakeup_new(probe_wakeup, NULL);
555 if (ret) {
556 pr_info("wakeup trace: Couldn't activate tracepoint"
557 " probe to kernel_sched_wakeup_new\n");
558 goto fail_deprobe;
561 ret = register_trace_sched_switch(probe_wakeup_sched_switch, NULL);
562 if (ret) {
563 pr_info("sched trace: Couldn't activate tracepoint"
564 " probe to kernel_sched_switch\n");
565 goto fail_deprobe_wake_new;
568 ret = register_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
569 if (ret) {
570 pr_info("wakeup trace: Couldn't activate tracepoint"
571 " probe to kernel_sched_migrate_task\n");
572 return;
575 wakeup_reset(tr);
578 * Don't let the tracer_enabled = 1 show up before
579 * the wakeup_task is reset. This may be overkill since
580 * wakeup_reset does a spin_unlock after setting the
581 * wakeup_task to NULL, but I want to be safe.
582 * This is a slow path anyway.
584 smp_wmb();
586 if (start_func_tracer(is_graph()))
587 printk(KERN_ERR "failed to start wakeup tracer\n");
589 return;
590 fail_deprobe_wake_new:
591 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
592 fail_deprobe:
593 unregister_trace_sched_wakeup(probe_wakeup, NULL);
596 static void stop_wakeup_tracer(struct trace_array *tr)
598 tracer_enabled = 0;
599 stop_func_tracer(is_graph());
600 unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
601 unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
602 unregister_trace_sched_wakeup(probe_wakeup, NULL);
603 unregister_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
606 static int __wakeup_tracer_init(struct trace_array *tr)
608 save_flags = trace_flags;
610 /* non overwrite screws up the latency tracers */
611 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
612 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
614 tracing_max_latency = 0;
615 wakeup_trace = tr;
616 start_wakeup_tracer(tr);
617 return 0;
620 static int wakeup_tracer_init(struct trace_array *tr)
622 wakeup_dl = 0;
623 wakeup_rt = 0;
624 return __wakeup_tracer_init(tr);
627 static int wakeup_rt_tracer_init(struct trace_array *tr)
629 wakeup_dl = 0;
630 wakeup_rt = 1;
631 return __wakeup_tracer_init(tr);
634 static int wakeup_dl_tracer_init(struct trace_array *tr)
636 wakeup_dl = 1;
637 wakeup_rt = 0;
638 return __wakeup_tracer_init(tr);
641 static void wakeup_tracer_reset(struct trace_array *tr)
643 int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
644 int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
646 stop_wakeup_tracer(tr);
647 /* make sure we put back any tasks we are tracing */
648 wakeup_reset(tr);
650 set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
651 set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
654 static void wakeup_tracer_start(struct trace_array *tr)
656 wakeup_reset(tr);
657 tracer_enabled = 1;
660 static void wakeup_tracer_stop(struct trace_array *tr)
662 tracer_enabled = 0;
665 static struct tracer wakeup_tracer __read_mostly =
667 .name = "wakeup",
668 .init = wakeup_tracer_init,
669 .reset = wakeup_tracer_reset,
670 .start = wakeup_tracer_start,
671 .stop = wakeup_tracer_stop,
672 .print_max = true,
673 .print_header = wakeup_print_header,
674 .print_line = wakeup_print_line,
675 .flags = &tracer_flags,
676 .set_flag = wakeup_set_flag,
677 .flag_changed = wakeup_flag_changed,
678 #ifdef CONFIG_FTRACE_SELFTEST
679 .selftest = trace_selftest_startup_wakeup,
680 #endif
681 .open = wakeup_trace_open,
682 .close = wakeup_trace_close,
683 .use_max_tr = true,
686 static struct tracer wakeup_rt_tracer __read_mostly =
688 .name = "wakeup_rt",
689 .init = wakeup_rt_tracer_init,
690 .reset = wakeup_tracer_reset,
691 .start = wakeup_tracer_start,
692 .stop = wakeup_tracer_stop,
693 .wait_pipe = poll_wait_pipe,
694 .print_max = true,
695 .print_header = wakeup_print_header,
696 .print_line = wakeup_print_line,
697 .flags = &tracer_flags,
698 .set_flag = wakeup_set_flag,
699 .flag_changed = wakeup_flag_changed,
700 #ifdef CONFIG_FTRACE_SELFTEST
701 .selftest = trace_selftest_startup_wakeup,
702 #endif
703 .open = wakeup_trace_open,
704 .close = wakeup_trace_close,
705 .use_max_tr = true,
708 static struct tracer wakeup_dl_tracer __read_mostly =
710 .name = "wakeup_dl",
711 .init = wakeup_dl_tracer_init,
712 .reset = wakeup_tracer_reset,
713 .start = wakeup_tracer_start,
714 .stop = wakeup_tracer_stop,
715 .wait_pipe = poll_wait_pipe,
716 .print_max = true,
717 .print_header = wakeup_print_header,
718 .print_line = wakeup_print_line,
719 .flags = &tracer_flags,
720 .set_flag = wakeup_set_flag,
721 .flag_changed = wakeup_flag_changed,
722 #ifdef CONFIG_FTRACE_SELFTEST
723 .selftest = trace_selftest_startup_wakeup,
724 #endif
725 .open = wakeup_trace_open,
726 .close = wakeup_trace_close,
727 .use_max_tr = true,
730 __init static int init_wakeup_tracer(void)
732 int ret;
734 ret = register_tracer(&wakeup_tracer);
735 if (ret)
736 return ret;
738 ret = register_tracer(&wakeup_rt_tracer);
739 if (ret)
740 return ret;
742 ret = register_tracer(&wakeup_dl_tracer);
743 if (ret)
744 return ret;
746 return 0;
748 core_initcall(init_wakeup_tracer);