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 #define TRACE_GRAPH_INDENT      2
  18
  19 /* Flag options */
  20 #define TRACE_GRAPH_PRINT_OVERRUN       0x1
  21 #define TRACE_GRAPH_PRINT_CPU           0x2
  22 #define TRACE_GRAPH_PRINT_OVERHEAD      0x4
  23 #define TRACE_GRAPH_PRINT_PROC          0x8
  24 #define TRACE_GRAPH_PRINT_DURATION      0x10
  25 #define TRACE_GRAPH_PRINT_ABS_TIME      0X20
  26
  27 static struct tracer_opt trace_opts[] = {
  28         /* Display overruns? (for self-debug purpose) */
  29         { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
  30         /* Display CPU ? */
  31         { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
  32         /* Display Overhead ? */
  33         { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
  34         /* Display proc name/pid */
  35         { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
  36         /* Display duration of execution */
  37         { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
  38         /* Display absolute time of an entry */
  39         { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
  40         { } /* Empty entry */
  41 };
  42
  43 static struct tracer_flags tracer_flags = {
  44         /* Don't display overruns and proc by default */
  45         .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
  46                TRACE_GRAPH_PRINT_DURATION,
  47         .opts = trace_opts
  48 };
  49
  50 /* pid on the last trace processed */
  51
  52
  53 static int graph_trace_init(struct trace_array *tr)
  54 {
  55         int ret = register_ftrace_graph(&trace_graph_return,
  56                                         &trace_graph_entry);
  57         if (ret)
  58                 return ret;
  59         tracing_start_cmdline_record();
  60
  61         return 0;
  62 }
  63
  64 static void graph_trace_reset(struct trace_array *tr)
  65 {
  66         tracing_stop_cmdline_record();
  67         unregister_ftrace_graph();
  68 }
  69
  70 static inline int log10_cpu(int nb)
  71 {
  72         if (nb / 100)
  73                 return 3;
  74         if (nb / 10)
  75                 return 2;
  76         return 1;
  77 }
  78
  79 static enum print_line_t
  80 print_graph_cpu(struct trace_seq *s, int cpu)
  81 {
  82         int i;
  83         int ret;
  84         int log10_this = log10_cpu(cpu);
  85         int log10_all = log10_cpu(cpumask_weight(cpu_online_mask));
  86
  87
  88         /*
  89          * Start with a space character - to make it stand out
  90          * to the right a bit when trace output is pasted into
  91          * email:
  92          */
  93         ret = trace_seq_printf(s, " ");
  94
  95         /*
  96          * Tricky - we space the CPU field according to the max
  97          * number of online CPUs. On a 2-cpu system it would take
  98          * a maximum of 1 digit - on a 128 cpu system it would
  99          * take up to 3 digits:
 100          */
 101         for (i = 0; i < log10_all - log10_this; i++) {
 102                 ret = trace_seq_printf(s, " ");
 103                 if (!ret)
 104                         return TRACE_TYPE_PARTIAL_LINE;
 105         }
 106         ret = trace_seq_printf(s, "%d) ", cpu);
 107         if (!ret)
 108                 return TRACE_TYPE_PARTIAL_LINE;
 109
 110         return TRACE_TYPE_HANDLED;
 111 }
 112
 113 #define TRACE_GRAPH_PROCINFO_LENGTH     14
 114
 115 static enum print_line_t
 116 print_graph_proc(struct trace_seq *s, pid_t pid)
 117 {
 118         int i;
 119         int ret;
 120         int len;
 121         char comm[8];
 122         int spaces = 0;
 123         /* sign + log10(MAX_INT) + '\0' */
 124         char pid_str[11];
 125
 126         strncpy(comm, trace_find_cmdline(pid), 7);
 127         comm[7] = '\0';
 128         sprintf(pid_str, "%d", pid);
 129
 130         /* 1 stands for the "-" character */
 131         len = strlen(comm) + strlen(pid_str) + 1;
 132
 133         if (len < TRACE_GRAPH_PROCINFO_LENGTH)
 134                 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
 135
 136         /* First spaces to align center */
 137         for (i = 0; i < spaces / 2; i++) {
 138                 ret = trace_seq_printf(s, " ");
 139                 if (!ret)
 140                         return TRACE_TYPE_PARTIAL_LINE;
 141         }
 142
 143         ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
 144         if (!ret)
 145                 return TRACE_TYPE_PARTIAL_LINE;
 146
 147         /* Last spaces to align center */
 148         for (i = 0; i < spaces - (spaces / 2); i++) {
 149                 ret = trace_seq_printf(s, " ");
 150                 if (!ret)
 151                         return TRACE_TYPE_PARTIAL_LINE;
 152         }
 153         return TRACE_TYPE_HANDLED;
 154 }
 155
 156
 157 /* If the pid changed since the last trace, output this event */
 158 static enum print_line_t
 159 verif_pid(struct trace_seq *s, pid_t pid, int cpu, pid_t *last_pids_cpu)
 160 {
 161         pid_t prev_pid;
 162         pid_t *last_pid;
 163         int ret;
 164
 165         if (!last_pids_cpu)
 166                 return TRACE_TYPE_HANDLED;
 167
 168         last_pid = per_cpu_ptr(last_pids_cpu, cpu);
 169
 170         if (*last_pid == pid)
 171                 return TRACE_TYPE_HANDLED;
 172
 173         prev_pid = *last_pid;
 174         *last_pid = pid;
 175
 176         if (prev_pid == -1)
 177                 return TRACE_TYPE_HANDLED;
 178 /*
 179  * Context-switch trace line:
 180
 181  ------------------------------------------
 182  | 1)  migration/0--1  =>  sshd-1755
 183  ------------------------------------------
 184
 185  */
 186         ret = trace_seq_printf(s,
 187                 " ------------------------------------------\n");
 188         if (!ret)
 189                 TRACE_TYPE_PARTIAL_LINE;
 190
 191         ret = print_graph_cpu(s, cpu);
 192         if (ret == TRACE_TYPE_PARTIAL_LINE)
 193                 TRACE_TYPE_PARTIAL_LINE;
 194
 195         ret = print_graph_proc(s, prev_pid);
 196         if (ret == TRACE_TYPE_PARTIAL_LINE)
 197                 TRACE_TYPE_PARTIAL_LINE;
 198
 199         ret = trace_seq_printf(s, " => ");
 200         if (!ret)
 201                 TRACE_TYPE_PARTIAL_LINE;
 202
 203         ret = print_graph_proc(s, pid);
 204         if (ret == TRACE_TYPE_PARTIAL_LINE)
 205                 TRACE_TYPE_PARTIAL_LINE;
 206
 207         ret = trace_seq_printf(s,
 208                 "\n ------------------------------------------\n\n");
 209         if (!ret)
 210                 TRACE_TYPE_PARTIAL_LINE;
 211
 212         return ret;
 213 }
 214
 215 static bool
 216 trace_branch_is_leaf(struct trace_iterator *iter,
 217                 struct ftrace_graph_ent_entry *curr)
 218 {
 219         struct ring_buffer_iter *ring_iter;
 220         struct ring_buffer_event *event;
 221         struct ftrace_graph_ret_entry *next;
 222
 223         ring_iter = iter->buffer_iter[iter->cpu];
 224
 225         if (!ring_iter)
 226                 return false;
 227
 228         event = ring_buffer_iter_peek(ring_iter, NULL);
 229
 230         if (!event)
 231                 return false;
 232
 233         next = ring_buffer_event_data(event);
 234
 235         if (next->ent.type != TRACE_GRAPH_RET)
 236                 return false;
 237
 238         if (curr->ent.pid != next->ent.pid ||
 239                         curr->graph_ent.func != next->ret.func)
 240                 return false;
 241
 242         return true;
 243 }
 244
 245 /* Signal a overhead of time execution to the output */
 246 static int
 247 print_graph_overhead(unsigned long long duration, struct trace_seq *s)
 248 {
 249         /* If duration disappear, we don't need anything */
 250         if (!(tracer_flags.val & TRACE_GRAPH_PRINT_DURATION))
 251                 return 1;
 252
 253         /* Non nested entry or return */
 254         if (duration == -1)
 255                 return trace_seq_printf(s, "  ");
 256
 257         if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
 258                 /* Duration exceeded 100 msecs */
 259                 if (duration > 100000ULL)
 260                         return trace_seq_printf(s, "! ");
 261
 262                 /* Duration exceeded 10 msecs */
 263                 if (duration > 10000ULL)
 264                         return trace_seq_printf(s, "+ ");
 265         }
 266
 267         return trace_seq_printf(s, "  ");
 268 }
 269
 270 static enum print_line_t
 271 print_graph_irq(struct trace_seq *s, unsigned long addr,
 272                 enum trace_type type, int cpu, pid_t pid)
 273 {
 274         int ret;
 275
 276         if (addr < (unsigned long)__irqentry_text_start ||
 277                 addr >= (unsigned long)__irqentry_text_end)
 278                 return TRACE_TYPE_UNHANDLED;
 279
 280         /* Cpu */
 281         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
 282                 ret = print_graph_cpu(s, cpu);
 283                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 284                         return TRACE_TYPE_PARTIAL_LINE;
 285         }
 286         /* Proc */
 287         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
 288                 ret = print_graph_proc(s, pid);
 289                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 290                         return TRACE_TYPE_PARTIAL_LINE;
 291                 ret = trace_seq_printf(s, " | ");
 292                 if (!ret)
 293                         return TRACE_TYPE_PARTIAL_LINE;
 294         }
 295
 296         /* No overhead */
 297         ret = print_graph_overhead(-1, s);
 298         if (!ret)
 299                 return TRACE_TYPE_PARTIAL_LINE;
 300
 301         if (type == TRACE_GRAPH_ENT)
 302                 ret = trace_seq_printf(s, "==========>");
 303         else
 304                 ret = trace_seq_printf(s, "<==========");
 305
 306         if (!ret)
 307                 return TRACE_TYPE_PARTIAL_LINE;
 308
 309         /* Don't close the duration column if haven't one */
 310         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 311                 trace_seq_printf(s, " |");
 312         ret = trace_seq_printf(s, "\n");
 313
 314         if (!ret)
 315                 return TRACE_TYPE_PARTIAL_LINE;
 316         return TRACE_TYPE_HANDLED;
 317 }
 318
 319 static enum print_line_t
 320 print_graph_duration(unsigned long long duration, struct trace_seq *s)
 321 {
 322         unsigned long nsecs_rem = do_div(duration, 1000);
 323         /* log10(ULONG_MAX) + '\0' */
 324         char msecs_str[21];
 325         char nsecs_str[5];
 326         int ret, len;
 327         int i;
 328
 329         sprintf(msecs_str, "%lu", (unsigned long) duration);
 330
 331         /* Print msecs */
 332         ret = trace_seq_printf(s, "%s", msecs_str);
 333         if (!ret)
 334                 return TRACE_TYPE_PARTIAL_LINE;
 335
 336         len = strlen(msecs_str);
 337
 338         /* Print nsecs (we don't want to exceed 7 numbers) */
 339         if (len < 7) {
 340                 snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem);
 341                 ret = trace_seq_printf(s, ".%s", nsecs_str);
 342                 if (!ret)
 343                         return TRACE_TYPE_PARTIAL_LINE;
 344                 len += strlen(nsecs_str);
 345         }
 346
 347         ret = trace_seq_printf(s, " us ");
 348         if (!ret)
 349                 return TRACE_TYPE_PARTIAL_LINE;
 350
 351         /* Print remaining spaces to fit the row's width */
 352         for (i = len; i < 7; i++) {
 353                 ret = trace_seq_printf(s, " ");
 354                 if (!ret)
 355                         return TRACE_TYPE_PARTIAL_LINE;
 356         }
 357
 358         ret = trace_seq_printf(s, "|  ");
 359         if (!ret)
 360                 return TRACE_TYPE_PARTIAL_LINE;
 361         return TRACE_TYPE_HANDLED;
 362
 363 }
 364
 365 static int print_graph_abs_time(u64 t, struct trace_seq *s)
 366 {
 367         unsigned long usecs_rem;
 368
 369         usecs_rem = do_div(t, 1000000000);
 370         usecs_rem /= 1000;
 371
 372         return trace_seq_printf(s, "%5lu.%06lu |  ",
 373                         (unsigned long)t, usecs_rem);
 374 }
 375
 376 /* Case of a leaf function on its call entry */
 377 static enum print_line_t
 378 print_graph_entry_leaf(struct trace_iterator *iter,
 379                 struct ftrace_graph_ent_entry *entry, struct trace_seq *s)
 380 {
 381         struct ftrace_graph_ret_entry *ret_entry;
 382         struct ftrace_graph_ret *graph_ret;
 383         struct ring_buffer_event *event;
 384         struct ftrace_graph_ent *call;
 385         unsigned long long duration;
 386         int ret;
 387         int i;
 388
 389         event = ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
 390         ret_entry = ring_buffer_event_data(event);
 391         graph_ret = &ret_entry->ret;
 392         call = &entry->graph_ent;
 393         duration = graph_ret->rettime - graph_ret->calltime;
 394
 395         /* Overhead */
 396         ret = print_graph_overhead(duration, s);
 397         if (!ret)
 398                 return TRACE_TYPE_PARTIAL_LINE;
 399
 400         /* Duration */
 401         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 402                 ret = print_graph_duration(duration, s);
 403                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 404                         return TRACE_TYPE_PARTIAL_LINE;
 405         }
 406
 407         /* Function */
 408         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 409                 ret = trace_seq_printf(s, " ");
 410                 if (!ret)
 411                         return TRACE_TYPE_PARTIAL_LINE;
 412         }
 413
 414         ret = seq_print_ip_sym(s, call->func, 0);
 415         if (!ret)
 416                 return TRACE_TYPE_PARTIAL_LINE;
 417
 418         ret = trace_seq_printf(s, "();\n");
 419         if (!ret)
 420                 return TRACE_TYPE_PARTIAL_LINE;
 421
 422         return TRACE_TYPE_HANDLED;
 423 }
 424
 425 static enum print_line_t
 426 print_graph_entry_nested(struct ftrace_graph_ent_entry *entry,
 427                         struct trace_seq *s, pid_t pid, int cpu)
 428 {
 429         int i;
 430         int ret;
 431         struct ftrace_graph_ent *call = &entry->graph_ent;
 432
 433         /* No overhead */
 434         ret = print_graph_overhead(-1, s);
 435         if (!ret)
 436                 return TRACE_TYPE_PARTIAL_LINE;
 437
 438         /* No time */
 439         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 440                 ret = trace_seq_printf(s, "            |  ");
 441                 if (!ret)
 442                         return TRACE_TYPE_PARTIAL_LINE;
 443         }
 444
 445         /* Function */
 446         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 447                 ret = trace_seq_printf(s, " ");
 448                 if (!ret)
 449                         return TRACE_TYPE_PARTIAL_LINE;
 450         }
 451
 452         ret = seq_print_ip_sym(s, call->func, 0);
 453         if (!ret)
 454                 return TRACE_TYPE_PARTIAL_LINE;
 455
 456         ret = trace_seq_printf(s, "() {\n");
 457         if (!ret)
 458                 return TRACE_TYPE_PARTIAL_LINE;
 459
 460         return TRACE_TYPE_HANDLED;
 461 }
 462
 463 static enum print_line_t
 464 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
 465                         struct trace_iterator *iter)
 466 {
 467         int ret;
 468         int cpu = iter->cpu;
 469         pid_t *last_entry = iter->private;
 470         struct trace_entry *ent = iter->ent;
 471         struct ftrace_graph_ent *call = &field->graph_ent;
 472
 473         /* Pid */
 474         if (verif_pid(s, ent->pid, cpu, last_entry) == TRACE_TYPE_PARTIAL_LINE)
 475                 return TRACE_TYPE_PARTIAL_LINE;
 476
 477         /* Interrupt */
 478         ret = print_graph_irq(s, call->func, TRACE_GRAPH_ENT, cpu, ent->pid);
 479         if (ret == TRACE_TYPE_PARTIAL_LINE)
 480                 return TRACE_TYPE_PARTIAL_LINE;
 481
 482         /* Absolute time */
 483         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
 484                 ret = print_graph_abs_time(iter->ts, s);
 485                 if (!ret)
 486                         return TRACE_TYPE_PARTIAL_LINE;
 487         }
 488
 489         /* Cpu */
 490         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
 491                 ret = print_graph_cpu(s, cpu);
 492                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 493                         return TRACE_TYPE_PARTIAL_LINE;
 494         }
 495
 496         /* Proc */
 497         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
 498                 ret = print_graph_proc(s, ent->pid);
 499                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 500                         return TRACE_TYPE_PARTIAL_LINE;
 501
 502                 ret = trace_seq_printf(s, " | ");
 503                 if (!ret)
 504                         return TRACE_TYPE_PARTIAL_LINE;
 505         }
 506
 507         if (trace_branch_is_leaf(iter, field))
 508                 return print_graph_entry_leaf(iter, field, s);
 509         else
 510                 return print_graph_entry_nested(field, s, iter->ent->pid, cpu);
 511
 512 }
 513
 514 static enum print_line_t
 515 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 516                    struct trace_entry *ent, struct trace_iterator *iter)
 517 {
 518         int i;
 519         int ret;
 520         int cpu = iter->cpu;
 521         pid_t *last_pid = iter->private;
 522         unsigned long long duration = trace->rettime - trace->calltime;
 523
 524         /* Pid */
 525         if (verif_pid(s, ent->pid, cpu, last_pid) == TRACE_TYPE_PARTIAL_LINE)
 526                 return TRACE_TYPE_PARTIAL_LINE;
 527
 528         /* Absolute time */
 529         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
 530                 ret = print_graph_abs_time(iter->ts, s);
 531                 if (!ret)
 532                         return TRACE_TYPE_PARTIAL_LINE;
 533         }
 534
 535         /* Cpu */
 536         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
 537                 ret = print_graph_cpu(s, cpu);
 538                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 539                         return TRACE_TYPE_PARTIAL_LINE;
 540         }
 541
 542         /* Proc */
 543         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
 544                 ret = print_graph_proc(s, ent->pid);
 545                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 546                         return TRACE_TYPE_PARTIAL_LINE;
 547
 548                 ret = trace_seq_printf(s, " | ");
 549                 if (!ret)
 550                         return TRACE_TYPE_PARTIAL_LINE;
 551         }
 552
 553         /* Overhead */
 554         ret = print_graph_overhead(duration, s);
 555         if (!ret)
 556                 return TRACE_TYPE_PARTIAL_LINE;
 557
 558         /* Duration */
 559         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 560                 ret = print_graph_duration(duration, s);
 561                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 562                         return TRACE_TYPE_PARTIAL_LINE;
 563         }
 564
 565         /* Closing brace */
 566         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
 567                 ret = trace_seq_printf(s, " ");
 568                 if (!ret)
 569                         return TRACE_TYPE_PARTIAL_LINE;
 570         }
 571
 572         ret = trace_seq_printf(s, "}\n");
 573         if (!ret)
 574                 return TRACE_TYPE_PARTIAL_LINE;
 575
 576         /* Overrun */
 577         if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) {
 578                 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
 579                                         trace->overrun);
 580                 if (!ret)
 581                         return TRACE_TYPE_PARTIAL_LINE;
 582         }
 583
 584         ret = print_graph_irq(s, trace->func, TRACE_GRAPH_RET, cpu, ent->pid);
 585         if (ret == TRACE_TYPE_PARTIAL_LINE)
 586                 return TRACE_TYPE_PARTIAL_LINE;
 587
 588         return TRACE_TYPE_HANDLED;
 589 }
 590
 591 static enum print_line_t
 592 print_graph_comment(struct print_entry *trace, struct trace_seq *s,
 593                    struct trace_entry *ent, struct trace_iterator *iter)
 594 {
 595         int i;
 596         int ret;
 597         int cpu = iter->cpu;
 598         pid_t *last_pid = iter->private;
 599
 600         /* Absolute time */
 601         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
 602                 ret = print_graph_abs_time(iter->ts, s);
 603                 if (!ret)
 604                         return TRACE_TYPE_PARTIAL_LINE;
 605         }
 606
 607         /* Pid */
 608         if (verif_pid(s, ent->pid, cpu, last_pid) == TRACE_TYPE_PARTIAL_LINE)
 609                 return TRACE_TYPE_PARTIAL_LINE;
 610
 611         /* Cpu */
 612         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
 613                 ret = print_graph_cpu(s, cpu);
 614                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 615                         return TRACE_TYPE_PARTIAL_LINE;
 616         }
 617
 618         /* Proc */
 619         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
 620                 ret = print_graph_proc(s, ent->pid);
 621                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 622                         return TRACE_TYPE_PARTIAL_LINE;
 623
 624                 ret = trace_seq_printf(s, " | ");
 625                 if (!ret)
 626                         return TRACE_TYPE_PARTIAL_LINE;
 627         }
 628
 629         /* No overhead */
 630         ret = print_graph_overhead(-1, s);
 631         if (!ret)
 632                 return TRACE_TYPE_PARTIAL_LINE;
 633
 634         /* No time */
 635         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 636                 ret = trace_seq_printf(s, "            |  ");
 637                 if (!ret)
 638                         return TRACE_TYPE_PARTIAL_LINE;
 639         }
 640
 641         /* Indentation */
 642         if (trace->depth > 0)
 643                 for (i = 0; i < (trace->depth + 1) * TRACE_GRAPH_INDENT; i++) {
 644                         ret = trace_seq_printf(s, " ");
 645                         if (!ret)
 646                                 return TRACE_TYPE_PARTIAL_LINE;
 647                 }
 648
 649         /* The comment */
 650         ret = trace_seq_printf(s, "/* %s", trace->buf);
 651         if (!ret)
 652                 return TRACE_TYPE_PARTIAL_LINE;
 653
 654         /* Strip ending newline */
 655         if (s->buffer[s->len - 1] == '\n') {
 656                 s->buffer[s->len - 1] = '\0';
 657                 s->len--;
 658         }
 659
 660         ret = trace_seq_printf(s, " */\n");
 661         if (!ret)
 662                 return TRACE_TYPE_PARTIAL_LINE;
 663
 664         return TRACE_TYPE_HANDLED;
 665 }
 666
 667
 668 enum print_line_t
 669 print_graph_function(struct trace_iterator *iter)
 670 {
 671         struct trace_seq *s = &iter->seq;
 672         struct trace_entry *entry = iter->ent;
 673
 674         switch (entry->type) {
 675         case TRACE_GRAPH_ENT: {
 676                 struct ftrace_graph_ent_entry *field;
 677                 trace_assign_type(field, entry);
 678                 return print_graph_entry(field, s, iter);
 679         }
 680         case TRACE_GRAPH_RET: {
 681                 struct ftrace_graph_ret_entry *field;
 682                 trace_assign_type(field, entry);
 683                 return print_graph_return(&field->ret, s, entry, iter);
 684         }
 685         case TRACE_PRINT: {
 686                 struct print_entry *field;
 687                 trace_assign_type(field, entry);
 688                 return print_graph_comment(field, s, entry, iter);
 689         }
 690         default:
 691                 return TRACE_TYPE_UNHANDLED;
 692         }
 693 }
 694
 695 static void print_graph_headers(struct seq_file *s)
 696 {
 697         /* 1st line */
 698         seq_printf(s, "# ");
 699         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
 700                 seq_printf(s, "     TIME       ");
 701         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
 702                 seq_printf(s, "CPU");
 703         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
 704                 seq_printf(s, "  TASK/PID      ");
 705         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 706                 seq_printf(s, "  DURATION   ");
 707         seq_printf(s, "               FUNCTION CALLS\n");
 708
 709         /* 2nd line */
 710         seq_printf(s, "# ");
 711         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
 712                 seq_printf(s, "      |         ");
 713         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
 714                 seq_printf(s, "|  ");
 715         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
 716                 seq_printf(s, "  |    |        ");
 717         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 718                 seq_printf(s, "   |   |      ");
 719         seq_printf(s, "               |   |   |   |\n");
 720 }
 721
 722 static void graph_trace_open(struct trace_iterator *iter)
 723 {
 724         /* pid on the last trace processed */
 725         pid_t *last_pid = alloc_percpu(pid_t);
 726         int cpu;
 727
 728         if (!last_pid)
 729                 pr_warning("function graph tracer: not enough memory\n");
 730         else
 731                 for_each_possible_cpu(cpu) {
 732                         pid_t *pid = per_cpu_ptr(last_pid, cpu);
 733                         *pid = -1;
 734                 }
 735
 736         iter->private = last_pid;
 737 }
 738
 739 static void graph_trace_close(struct trace_iterator *iter)
 740 {
 741         percpu_free(iter->private);
 742 }
 743
 744 static struct tracer graph_trace __read_mostly = {
 745         .name           = "function_graph",
 746         .open           = graph_trace_open,
 747         .close          = graph_trace_close,
 748         .init           = graph_trace_init,
 749         .reset          = graph_trace_reset,
 750         .print_line     = print_graph_function,
 751         .print_header   = print_graph_headers,
 752         .flags          = &tracer_flags,
 753 };
 754
 755 static __init int init_graph_trace(void)
 756 {
 757         return register_tracer(&graph_trace);
 758 }
 759
 760 device_initcall(init_graph_trace);