Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
[linux-2.6] / kernel / trace / trace_functions_graph.c
1 /*
2  *
3  * Function graph tracer.
4  * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
5  * Mostly borrowed from function tracer which
6  * is Copyright (c) Steven Rostedt <srostedt@redhat.com>
7  *
8  */
9 #include <linux/debugfs.h>
10 #include <linux/uaccess.h>
11 #include <linux/ftrace.h>
12 #include <linux/fs.h>
13
14 #include "trace.h"
15 #include "trace_output.h"
16
17 struct fgraph_data {
18         pid_t           last_pid;
19         int             depth;
20 };
21
22 #define TRACE_GRAPH_INDENT      2
23
24 /* Flag options */
25 #define TRACE_GRAPH_PRINT_OVERRUN       0x1
26 #define TRACE_GRAPH_PRINT_CPU           0x2
27 #define TRACE_GRAPH_PRINT_OVERHEAD      0x4
28 #define TRACE_GRAPH_PRINT_PROC          0x8
29 #define TRACE_GRAPH_PRINT_DURATION      0x10
30 #define TRACE_GRAPH_PRINT_ABS_TIME      0X20
31
32 static struct tracer_opt trace_opts[] = {
33         /* Display overruns? (for self-debug purpose) */
34         { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
35         /* Display CPU ? */
36         { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
37         /* Display Overhead ? */
38         { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
39         /* Display proc name/pid */
40         { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
41         /* Display duration of execution */
42         { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
43         /* Display absolute time of an entry */
44         { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
45         { } /* Empty entry */
46 };
47
48 static struct tracer_flags tracer_flags = {
49         /* Don't display overruns and proc by default */
50         .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
51                TRACE_GRAPH_PRINT_DURATION,
52         .opts = trace_opts
53 };
54
55 /* pid on the last trace processed */
56
57
58 /* Add a function return address to the trace stack on thread info.*/
59 int
60 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth)
61 {
62         unsigned long long calltime;
63         int index;
64
65         if (!current->ret_stack)
66                 return -EBUSY;
67
68         /*
69          * We must make sure the ret_stack is tested before we read
70          * anything else.
71          */
72         smp_rmb();
73
74         /* The return trace stack is full */
75         if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
76                 atomic_inc(&current->trace_overrun);
77                 return -EBUSY;
78         }
79
80         calltime = trace_clock_local();
81
82         index = ++current->curr_ret_stack;
83         barrier();
84         current->ret_stack[index].ret = ret;
85         current->ret_stack[index].func = func;
86         current->ret_stack[index].calltime = calltime;
87         current->ret_stack[index].subtime = 0;
88         *depth = index;
89
90         return 0;
91 }
92
93 /* Retrieve a function return address to the trace stack on thread info.*/
94 static void
95 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
96 {
97         int index;
98
99         index = current->curr_ret_stack;
100
101         if (unlikely(index < 0)) {
102                 ftrace_graph_stop();
103                 WARN_ON(1);
104                 /* Might as well panic, otherwise we have no where to go */
105                 *ret = (unsigned long)panic;
106                 return;
107         }
108
109         *ret = current->ret_stack[index].ret;
110         trace->func = current->ret_stack[index].func;
111         trace->calltime = current->ret_stack[index].calltime;
112         trace->overrun = atomic_read(&current->trace_overrun);
113         trace->depth = index;
114 }
115
116 /*
117  * Send the trace to the ring-buffer.
118  * @return the original return address.
119  */
120 unsigned long ftrace_return_to_handler(void)
121 {
122         struct ftrace_graph_ret trace;
123         unsigned long ret;
124
125         ftrace_pop_return_trace(&trace, &ret);
126         trace.rettime = trace_clock_local();
127         ftrace_graph_return(&trace);
128         barrier();
129         current->curr_ret_stack--;
130
131         if (unlikely(!ret)) {
132                 ftrace_graph_stop();
133                 WARN_ON(1);
134                 /* Might as well panic. What else to do? */
135                 ret = (unsigned long)panic;
136         }
137
138         return ret;
139 }
140
141 static int graph_trace_init(struct trace_array *tr)
142 {
143         int ret = register_ftrace_graph(&trace_graph_return,
144                                         &trace_graph_entry);
145         if (ret)
146                 return ret;
147         tracing_start_cmdline_record();
148
149         return 0;
150 }
151
152 static void graph_trace_reset(struct trace_array *tr)
153 {
154         tracing_stop_cmdline_record();
155         unregister_ftrace_graph();
156 }
157
158 static inline int log10_cpu(int nb)
159 {
160         if (nb / 100)
161                 return 3;
162         if (nb / 10)
163                 return 2;
164         return 1;
165 }
166
167 static enum print_line_t
168 print_graph_cpu(struct trace_seq *s, int cpu)
169 {
170         int i;
171         int ret;
172         int log10_this = log10_cpu(cpu);
173         int log10_all = log10_cpu(cpumask_weight(cpu_online_mask));
174
175
176         /*
177          * Start with a space character - to make it stand out
178          * to the right a bit when trace output is pasted into
179          * email:
180          */
181         ret = trace_seq_printf(s, " ");
182
183         /*
184          * Tricky - we space the CPU field according to the max
185          * number of online CPUs. On a 2-cpu system it would take
186          * a maximum of 1 digit - on a 128 cpu system it would
187          * take up to 3 digits:
188          */
189         for (i = 0; i < log10_all - log10_this; i++) {
190                 ret = trace_seq_printf(s, " ");
191                 if (!ret)
192                         return TRACE_TYPE_PARTIAL_LINE;
193         }
194         ret = trace_seq_printf(s, "%d) ", cpu);
195         if (!ret)
196                 return TRACE_TYPE_PARTIAL_LINE;
197
198         return TRACE_TYPE_HANDLED;
199 }
200
201 #define TRACE_GRAPH_PROCINFO_LENGTH     14
202
203 static enum print_line_t
204 print_graph_proc(struct trace_seq *s, pid_t pid)
205 {
206         char comm[TASK_COMM_LEN];
207         /* sign + log10(MAX_INT) + '\0' */
208         char pid_str[11];
209         int spaces = 0;
210         int ret;
211         int len;
212         int i;
213
214         trace_find_cmdline(pid, comm);
215         comm[7] = '\0';
216         sprintf(pid_str, "%d", pid);
217
218         /* 1 stands for the "-" character */
219         len = strlen(comm) + strlen(pid_str) + 1;
220
221         if (len < TRACE_GRAPH_PROCINFO_LENGTH)
222                 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
223
224         /* First spaces to align center */
225         for (i = 0; i < spaces / 2; i++) {
226                 ret = trace_seq_printf(s, " ");
227                 if (!ret)
228                         return TRACE_TYPE_PARTIAL_LINE;
229         }
230
231         ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
232         if (!ret)
233                 return TRACE_TYPE_PARTIAL_LINE;
234
235         /* Last spaces to align center */
236         for (i = 0; i < spaces - (spaces / 2); i++) {
237                 ret = trace_seq_printf(s, " ");
238                 if (!ret)
239                         return TRACE_TYPE_PARTIAL_LINE;
240         }
241         return TRACE_TYPE_HANDLED;
242 }
243
244
245 /* If the pid changed since the last trace, output this event */
246 static enum print_line_t
247 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
248 {
249         pid_t prev_pid;
250         pid_t *last_pid;
251         int ret;
252
253         if (!data)
254                 return TRACE_TYPE_HANDLED;
255
256         last_pid = &(per_cpu_ptr(data, cpu)->last_pid);
257
258         if (*last_pid == pid)
259                 return TRACE_TYPE_HANDLED;
260
261         prev_pid = *last_pid;
262         *last_pid = pid;
263
264         if (prev_pid == -1)
265                 return TRACE_TYPE_HANDLED;
266 /*
267  * Context-switch trace line:
268
269  ------------------------------------------
270  | 1)  migration/0--1  =>  sshd-1755
271  ------------------------------------------
272
273  */
274         ret = trace_seq_printf(s,
275                 " ------------------------------------------\n");
276         if (!ret)
277                 return TRACE_TYPE_PARTIAL_LINE;
278
279         ret = print_graph_cpu(s, cpu);
280         if (ret == TRACE_TYPE_PARTIAL_LINE)
281                 return TRACE_TYPE_PARTIAL_LINE;
282
283         ret = print_graph_proc(s, prev_pid);
284         if (ret == TRACE_TYPE_PARTIAL_LINE)
285                 return TRACE_TYPE_PARTIAL_LINE;
286
287         ret = trace_seq_printf(s, " => ");
288         if (!ret)
289                 return TRACE_TYPE_PARTIAL_LINE;
290
291         ret = print_graph_proc(s, pid);
292         if (ret == TRACE_TYPE_PARTIAL_LINE)
293                 return TRACE_TYPE_PARTIAL_LINE;
294
295         ret = trace_seq_printf(s,
296                 "\n ------------------------------------------\n\n");
297         if (!ret)
298                 return TRACE_TYPE_PARTIAL_LINE;
299
300         return TRACE_TYPE_HANDLED;
301 }
302
303 static struct ftrace_graph_ret_entry *
304 get_return_for_leaf(struct trace_iterator *iter,
305                 struct ftrace_graph_ent_entry *curr)
306 {
307         struct ring_buffer_iter *ring_iter;
308         struct ring_buffer_event *event;
309         struct ftrace_graph_ret_entry *next;
310
311         ring_iter = iter->buffer_iter[iter->cpu];
312
313         /* First peek to compare current entry and the next one */
314         if (ring_iter)
315                 event = ring_buffer_iter_peek(ring_iter, NULL);
316         else {
317         /* We need to consume the current entry to see the next one */
318                 ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL);
319                 event = ring_buffer_peek(iter->tr->buffer, iter->cpu,
320                                         NULL);
321         }
322
323         if (!event)
324                 return NULL;
325
326         next = ring_buffer_event_data(event);
327
328         if (next->ent.type != TRACE_GRAPH_RET)
329                 return NULL;
330
331         if (curr->ent.pid != next->ent.pid ||
332                         curr->graph_ent.func != next->ret.func)
333                 return NULL;
334
335         /* this is a leaf, now advance the iterator */
336         if (ring_iter)
337                 ring_buffer_read(ring_iter, NULL);
338
339         return next;
340 }
341
342 /* Signal a overhead of time execution to the output */
343 static int
344 print_graph_overhead(unsigned long long duration, struct trace_seq *s)
345 {
346         /* If duration disappear, we don't need anything */
347         if (!(tracer_flags.val & TRACE_GRAPH_PRINT_DURATION))
348                 return 1;
349
350         /* Non nested entry or return */
351         if (duration == -1)
352                 return trace_seq_printf(s, "  ");
353
354         if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
355                 /* Duration exceeded 100 msecs */
356                 if (duration > 100000ULL)
357                         return trace_seq_printf(s, "! ");
358
359                 /* Duration exceeded 10 msecs */
360                 if (duration > 10000ULL)
361                         return trace_seq_printf(s, "+ ");
362         }
363
364         return trace_seq_printf(s, "  ");
365 }
366
367 static int print_graph_abs_time(u64 t, struct trace_seq *s)
368 {
369         unsigned long usecs_rem;
370
371         usecs_rem = do_div(t, NSEC_PER_SEC);
372         usecs_rem /= 1000;
373
374         return trace_seq_printf(s, "%5lu.%06lu |  ",
375                         (unsigned long)t, usecs_rem);
376 }
377
378 static enum print_line_t
379 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
380                 enum trace_type type, int cpu, pid_t pid)
381 {
382         int ret;
383         struct trace_seq *s = &iter->seq;
384
385         if (addr < (unsigned long)__irqentry_text_start ||
386                 addr >= (unsigned long)__irqentry_text_end)
387                 return TRACE_TYPE_UNHANDLED;
388
389         /* Absolute time */
390         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
391                 ret = print_graph_abs_time(iter->ts, s);
392                 if (!ret)
393                         return TRACE_TYPE_PARTIAL_LINE;
394         }
395
396         /* Cpu */
397         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
398                 ret = print_graph_cpu(s, cpu);
399                 if (ret == TRACE_TYPE_PARTIAL_LINE)
400                         return TRACE_TYPE_PARTIAL_LINE;
401         }
402         /* Proc */
403         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
404                 ret = print_graph_proc(s, pid);
405                 if (ret == TRACE_TYPE_PARTIAL_LINE)
406                         return TRACE_TYPE_PARTIAL_LINE;
407                 ret = trace_seq_printf(s, " | ");
408                 if (!ret)
409                         return TRACE_TYPE_PARTIAL_LINE;
410         }
411
412         /* No overhead */
413         ret = print_graph_overhead(-1, s);
414         if (!ret)
415                 return TRACE_TYPE_PARTIAL_LINE;
416
417         if (type == TRACE_GRAPH_ENT)
418                 ret = trace_seq_printf(s, "==========>");
419         else
420                 ret = trace_seq_printf(s, "<==========");
421
422         if (!ret)
423                 return TRACE_TYPE_PARTIAL_LINE;
424
425         /* Don't close the duration column if haven't one */
426         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
427                 trace_seq_printf(s, " |");
428         ret = trace_seq_printf(s, "\n");
429
430         if (!ret)
431                 return TRACE_TYPE_PARTIAL_LINE;
432         return TRACE_TYPE_HANDLED;
433 }
434
435 enum print_line_t
436 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
437 {
438         unsigned long nsecs_rem = do_div(duration, 1000);
439         /* log10(ULONG_MAX) + '\0' */
440         char msecs_str[21];
441         char nsecs_str[5];
442         int ret, len;
443         int i;
444
445         sprintf(msecs_str, "%lu", (unsigned long) duration);
446
447         /* Print msecs */
448         ret = trace_seq_printf(s, "%s", msecs_str);
449         if (!ret)
450                 return TRACE_TYPE_PARTIAL_LINE;
451
452         len = strlen(msecs_str);
453
454         /* Print nsecs (we don't want to exceed 7 numbers) */
455         if (len < 7) {
456                 snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem);
457                 ret = trace_seq_printf(s, ".%s", nsecs_str);
458                 if (!ret)
459                         return TRACE_TYPE_PARTIAL_LINE;
460                 len += strlen(nsecs_str);
461         }
462
463         ret = trace_seq_printf(s, " us ");
464         if (!ret)
465                 return TRACE_TYPE_PARTIAL_LINE;
466
467         /* Print remaining spaces to fit the row's width */
468         for (i = len; i < 7; i++) {
469                 ret = trace_seq_printf(s, " ");
470                 if (!ret)
471                         return TRACE_TYPE_PARTIAL_LINE;
472         }
473         return TRACE_TYPE_HANDLED;
474 }
475
476 static enum print_line_t
477 print_graph_duration(unsigned long long duration, struct trace_seq *s)
478 {
479         int ret;
480
481         ret = trace_print_graph_duration(duration, s);
482         if (ret != TRACE_TYPE_HANDLED)
483                 return ret;
484
485         ret = trace_seq_printf(s, "|  ");
486         if (!ret)
487                 return TRACE_TYPE_PARTIAL_LINE;
488
489         return TRACE_TYPE_HANDLED;
490 }
491
492 /* Case of a leaf function on its call entry */
493 static enum print_line_t
494 print_graph_entry_leaf(struct trace_iterator *iter,
495                 struct ftrace_graph_ent_entry *entry,
496                 struct ftrace_graph_ret_entry *ret_entry, struct trace_seq *s)
497 {
498         struct fgraph_data *data = iter->private;
499         struct ftrace_graph_ret *graph_ret;
500         struct ftrace_graph_ent *call;
501         unsigned long long duration;
502         int ret;
503         int i;
504
505         graph_ret = &ret_entry->ret;
506         call = &entry->graph_ent;
507         duration = graph_ret->rettime - graph_ret->calltime;
508
509         if (data) {
510                 int cpu = iter->cpu;
511                 int *depth = &(per_cpu_ptr(data, cpu)->depth);
512
513                 /*
514                  * Comments display at + 1 to depth. Since
515                  * this is a leaf function, keep the comments
516                  * equal to this depth.
517                  */
518                 *depth = call->depth - 1;
519         }
520
521         /* Overhead */
522         ret = print_graph_overhead(duration, s);
523         if (!ret)
524                 return TRACE_TYPE_PARTIAL_LINE;
525
526         /* Duration */
527         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
528                 ret = print_graph_duration(duration, s);
529                 if (ret == TRACE_TYPE_PARTIAL_LINE)
530                         return TRACE_TYPE_PARTIAL_LINE;
531         }
532
533         /* Function */
534         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
535                 ret = trace_seq_printf(s, " ");
536                 if (!ret)
537                         return TRACE_TYPE_PARTIAL_LINE;
538         }
539
540         ret = seq_print_ip_sym(s, call->func, 0);
541         if (!ret)
542                 return TRACE_TYPE_PARTIAL_LINE;
543
544         ret = trace_seq_printf(s, "();\n");
545         if (!ret)
546                 return TRACE_TYPE_PARTIAL_LINE;
547
548         return TRACE_TYPE_HANDLED;
549 }
550
551 static enum print_line_t
552 print_graph_entry_nested(struct trace_iterator *iter,
553                          struct ftrace_graph_ent_entry *entry,
554                          struct trace_seq *s, int cpu)
555 {
556         struct ftrace_graph_ent *call = &entry->graph_ent;
557         struct fgraph_data *data = iter->private;
558         int ret;
559         int i;
560
561         if (data) {
562                 int cpu = iter->cpu;
563                 int *depth = &(per_cpu_ptr(data, cpu)->depth);
564
565                 *depth = call->depth;
566         }
567
568         /* No overhead */
569         ret = print_graph_overhead(-1, s);
570         if (!ret)
571                 return TRACE_TYPE_PARTIAL_LINE;
572
573         /* No time */
574         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
575                 ret = trace_seq_printf(s, "            |  ");
576                 if (!ret)
577                         return TRACE_TYPE_PARTIAL_LINE;
578         }
579
580         /* Function */
581         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
582                 ret = trace_seq_printf(s, " ");
583                 if (!ret)
584                         return TRACE_TYPE_PARTIAL_LINE;
585         }
586
587         ret = seq_print_ip_sym(s, call->func, 0);
588         if (!ret)
589                 return TRACE_TYPE_PARTIAL_LINE;
590
591         ret = trace_seq_printf(s, "() {\n");
592         if (!ret)
593                 return TRACE_TYPE_PARTIAL_LINE;
594
595         /*
596          * we already consumed the current entry to check the next one
597          * and see if this is a leaf.
598          */
599         return TRACE_TYPE_NO_CONSUME;
600 }
601
602 static enum print_line_t
603 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
604                      int type, unsigned long addr)
605 {
606         struct fgraph_data *data = iter->private;
607         struct trace_entry *ent = iter->ent;
608         int cpu = iter->cpu;
609         int ret;
610
611         /* Pid */
612         if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
613                 return TRACE_TYPE_PARTIAL_LINE;
614
615         if (type) {
616                 /* Interrupt */
617                 ret = print_graph_irq(iter, addr, type, cpu, ent->pid);
618                 if (ret == TRACE_TYPE_PARTIAL_LINE)
619                         return TRACE_TYPE_PARTIAL_LINE;
620         }
621
622         /* Absolute time */
623         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
624                 ret = print_graph_abs_time(iter->ts, s);
625                 if (!ret)
626                         return TRACE_TYPE_PARTIAL_LINE;
627         }
628
629         /* Cpu */
630         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
631                 ret = print_graph_cpu(s, cpu);
632                 if (ret == TRACE_TYPE_PARTIAL_LINE)
633                         return TRACE_TYPE_PARTIAL_LINE;
634         }
635
636         /* Proc */
637         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
638                 ret = print_graph_proc(s, ent->pid);
639                 if (ret == TRACE_TYPE_PARTIAL_LINE)
640                         return TRACE_TYPE_PARTIAL_LINE;
641
642                 ret = trace_seq_printf(s, " | ");
643                 if (!ret)
644                         return TRACE_TYPE_PARTIAL_LINE;
645         }
646
647         return 0;
648 }
649
650 static enum print_line_t
651 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
652                         struct trace_iterator *iter)
653 {
654         int cpu = iter->cpu;
655         struct ftrace_graph_ent *call = &field->graph_ent;
656         struct ftrace_graph_ret_entry *leaf_ret;
657
658         if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func))
659                 return TRACE_TYPE_PARTIAL_LINE;
660
661         leaf_ret = get_return_for_leaf(iter, field);
662         if (leaf_ret)
663                 return print_graph_entry_leaf(iter, field, leaf_ret, s);
664         else
665                 return print_graph_entry_nested(iter, field, s, cpu);
666
667 }
668
669 static enum print_line_t
670 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
671                    struct trace_entry *ent, struct trace_iterator *iter)
672 {
673         unsigned long long duration = trace->rettime - trace->calltime;
674         struct fgraph_data *data = iter->private;
675         pid_t pid = ent->pid;
676         int cpu = iter->cpu;
677         int ret;
678         int i;
679
680         if (data) {
681                 int cpu = iter->cpu;
682                 int *depth = &(per_cpu_ptr(data, cpu)->depth);
683
684                 /*
685                  * Comments display at + 1 to depth. This is the
686                  * return from a function, we now want the comments
687                  * to display at the same level of the bracket.
688                  */
689                 *depth = trace->depth - 1;
690         }
691
692         if (print_graph_prologue(iter, s, 0, 0))
693                 return TRACE_TYPE_PARTIAL_LINE;
694
695         /* Overhead */
696         ret = print_graph_overhead(duration, s);
697         if (!ret)
698                 return TRACE_TYPE_PARTIAL_LINE;
699
700         /* Duration */
701         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
702                 ret = print_graph_duration(duration, s);
703                 if (ret == TRACE_TYPE_PARTIAL_LINE)
704                         return TRACE_TYPE_PARTIAL_LINE;
705         }
706
707         /* Closing brace */
708         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
709                 ret = trace_seq_printf(s, " ");
710                 if (!ret)
711                         return TRACE_TYPE_PARTIAL_LINE;
712         }
713
714         ret = trace_seq_printf(s, "}\n");
715         if (!ret)
716                 return TRACE_TYPE_PARTIAL_LINE;
717
718         /* Overrun */
719         if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) {
720                 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
721                                         trace->overrun);
722                 if (!ret)
723                         return TRACE_TYPE_PARTIAL_LINE;
724         }
725
726         ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, cpu, pid);
727         if (ret == TRACE_TYPE_PARTIAL_LINE)
728                 return TRACE_TYPE_PARTIAL_LINE;
729
730         return TRACE_TYPE_HANDLED;
731 }
732
733 static enum print_line_t
734 print_graph_comment(struct trace_seq *s,  struct trace_entry *ent,
735                     struct trace_iterator *iter)
736 {
737         unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
738         struct fgraph_data *data = iter->private;
739         struct trace_event *event;
740         int depth = 0;
741         int ret;
742         int i;
743
744         if (data)
745                 depth = per_cpu_ptr(data, iter->cpu)->depth;
746
747         if (print_graph_prologue(iter, s, 0, 0))
748                 return TRACE_TYPE_PARTIAL_LINE;
749
750         /* No overhead */
751         ret = print_graph_overhead(-1, s);
752         if (!ret)
753                 return TRACE_TYPE_PARTIAL_LINE;
754
755         /* No time */
756         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
757                 ret = trace_seq_printf(s, "            |  ");
758                 if (!ret)
759                         return TRACE_TYPE_PARTIAL_LINE;
760         }
761
762         /* Indentation */
763         if (depth > 0)
764                 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
765                         ret = trace_seq_printf(s, " ");
766                         if (!ret)
767                                 return TRACE_TYPE_PARTIAL_LINE;
768                 }
769
770         /* The comment */
771         ret = trace_seq_printf(s, "/* ");
772         if (!ret)
773                 return TRACE_TYPE_PARTIAL_LINE;
774
775         switch (iter->ent->type) {
776         case TRACE_BPRINT:
777                 ret = trace_print_bprintk_msg_only(iter);
778                 if (ret != TRACE_TYPE_HANDLED)
779                         return ret;
780                 break;
781         case TRACE_PRINT:
782                 ret = trace_print_printk_msg_only(iter);
783                 if (ret != TRACE_TYPE_HANDLED)
784                         return ret;
785                 break;
786         default:
787                 event = ftrace_find_event(ent->type);
788                 if (!event)
789                         return TRACE_TYPE_UNHANDLED;
790
791                 ret = event->trace(iter, sym_flags);
792                 if (ret != TRACE_TYPE_HANDLED)
793                         return ret;
794         }
795
796         /* Strip ending newline */
797         if (s->buffer[s->len - 1] == '\n') {
798                 s->buffer[s->len - 1] = '\0';
799                 s->len--;
800         }
801
802         ret = trace_seq_printf(s, " */\n");
803         if (!ret)
804                 return TRACE_TYPE_PARTIAL_LINE;
805
806         return TRACE_TYPE_HANDLED;
807 }
808
809
810 enum print_line_t
811 print_graph_function(struct trace_iterator *iter)
812 {
813         struct trace_entry *entry = iter->ent;
814         struct trace_seq *s = &iter->seq;
815
816         switch (entry->type) {
817         case TRACE_GRAPH_ENT: {
818                 struct ftrace_graph_ent_entry *field;
819                 trace_assign_type(field, entry);
820                 return print_graph_entry(field, s, iter);
821         }
822         case TRACE_GRAPH_RET: {
823                 struct ftrace_graph_ret_entry *field;
824                 trace_assign_type(field, entry);
825                 return print_graph_return(&field->ret, s, entry, iter);
826         }
827         default:
828                 return print_graph_comment(s, entry, iter);
829         }
830
831         return TRACE_TYPE_HANDLED;
832 }
833
834 static void print_graph_headers(struct seq_file *s)
835 {
836         /* 1st line */
837         seq_printf(s, "# ");
838         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
839                 seq_printf(s, "     TIME       ");
840         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
841                 seq_printf(s, "CPU");
842         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
843                 seq_printf(s, "  TASK/PID      ");
844         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
845                 seq_printf(s, "  DURATION   ");
846         seq_printf(s, "               FUNCTION CALLS\n");
847
848         /* 2nd line */
849         seq_printf(s, "# ");
850         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
851                 seq_printf(s, "      |         ");
852         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
853                 seq_printf(s, "|  ");
854         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
855                 seq_printf(s, "  |    |        ");
856         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
857                 seq_printf(s, "   |   |      ");
858         seq_printf(s, "               |   |   |   |\n");
859 }
860
861 static void graph_trace_open(struct trace_iterator *iter)
862 {
863         /* pid and depth on the last trace processed */
864         struct fgraph_data *data = alloc_percpu(struct fgraph_data);
865         int cpu;
866
867         if (!data)
868                 pr_warning("function graph tracer: not enough memory\n");
869         else
870                 for_each_possible_cpu(cpu) {
871                         pid_t *pid = &(per_cpu_ptr(data, cpu)->last_pid);
872                         int *depth = &(per_cpu_ptr(data, cpu)->depth);
873                         *pid = -1;
874                         *depth = 0;
875                 }
876
877         iter->private = data;
878 }
879
880 static void graph_trace_close(struct trace_iterator *iter)
881 {
882         free_percpu(iter->private);
883 }
884
885 static struct tracer graph_trace __read_mostly = {
886         .name           = "function_graph",
887         .open           = graph_trace_open,
888         .close          = graph_trace_close,
889         .wait_pipe      = poll_wait_pipe,
890         .init           = graph_trace_init,
891         .reset          = graph_trace_reset,
892         .print_line     = print_graph_function,
893         .print_header   = print_graph_headers,
894         .flags          = &tracer_flags,
895 #ifdef CONFIG_FTRACE_SELFTEST
896         .selftest       = trace_selftest_startup_function_graph,
897 #endif
898 };
899
900 static __init int init_graph_trace(void)
901 {
902         return register_tracer(&graph_trace);
903 }
904
905 device_initcall(init_graph_trace);