git.oblomov.eu Git - linux-2.6/blob - 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 /* Add a function return address to the trace stack on thread info.*/
  54 int
  55 ftrace_push_return_trace(unsigned long ret, unsigned long long time,
  56                          unsigned long func, int *depth)
  57 {
  58         int index;
  59
  60         if (!current->ret_stack)
  61                 return -EBUSY;
  62
  63         /* The return trace stack is full */
  64         if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
  65                 atomic_inc(&current->trace_overrun);
  66                 return -EBUSY;
  67         }
  68
  69         index = ++current->curr_ret_stack;
  70         barrier();
  71         current->ret_stack[index].ret = ret;
  72         current->ret_stack[index].func = func;
  73         current->ret_stack[index].calltime = time;
  74         *depth = index;
  75
  76         return 0;
  77 }
  78
  79 /* Retrieve a function return address to the trace stack on thread info.*/
  80 void
  81 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
  82 {
  83         int index;
  84
  85         index = current->curr_ret_stack;
  86
  87         if (unlikely(index < 0)) {
  88                 ftrace_graph_stop();
  89                 WARN_ON(1);
  90                 /* Might as well panic, otherwise we have no where to go */
  91                 *ret = (unsigned long)panic;
  92                 return;
  93         }
  94
  95         *ret = current->ret_stack[index].ret;
  96         trace->func = current->ret_stack[index].func;
  97         trace->calltime = current->ret_stack[index].calltime;
  98         trace->overrun = atomic_read(&current->trace_overrun);
  99         trace->depth = index;
 100         barrier();
 101         current->curr_ret_stack--;
 102
 103 }
 104
 105 /*
 106  * Send the trace to the ring-buffer.
 107  * @return the original return address.
 108  */
 109 unsigned long ftrace_return_to_handler(void)
 110 {
 111         struct ftrace_graph_ret trace;
 112         unsigned long ret;
 113
 114         ftrace_pop_return_trace(&trace, &ret);
 115         trace.rettime = cpu_clock(raw_smp_processor_id());
 116         ftrace_graph_return(&trace);
 117
 118         if (unlikely(!ret)) {
 119                 ftrace_graph_stop();
 120                 WARN_ON(1);
 121                 /* Might as well panic. What else to do? */
 122                 ret = (unsigned long)panic;
 123         }
 124
 125         return ret;
 126 }
 127
 128 static int graph_trace_init(struct trace_array *tr)
 129 {
 130         int ret = register_ftrace_graph(&trace_graph_return,
 131                                         &trace_graph_entry);
 132         if (ret)
 133                 return ret;
 134         tracing_start_cmdline_record();
 135
 136         return 0;
 137 }
 138
 139 static void graph_trace_reset(struct trace_array *tr)
 140 {
 141         tracing_stop_cmdline_record();
 142         unregister_ftrace_graph();
 143 }
 144
 145 static inline int log10_cpu(int nb)
 146 {
 147         if (nb / 100)
 148                 return 3;
 149         if (nb / 10)
 150                 return 2;
 151         return 1;
 152 }
 153
 154 static enum print_line_t
 155 print_graph_cpu(struct trace_seq *s, int cpu)
 156 {
 157         int i;
 158         int ret;
 159         int log10_this = log10_cpu(cpu);
 160         int log10_all = log10_cpu(cpumask_weight(cpu_online_mask));
 161
 162
 163         /*
 164          * Start with a space character - to make it stand out
 165          * to the right a bit when trace output is pasted into
 166          * email:
 167          */
 168         ret = trace_seq_printf(s, " ");
 169
 170         /*
 171          * Tricky - we space the CPU field according to the max
 172          * number of online CPUs. On a 2-cpu system it would take
 173          * a maximum of 1 digit - on a 128 cpu system it would
 174          * take up to 3 digits:
 175          */
 176         for (i = 0; i < log10_all - log10_this; i++) {
 177                 ret = trace_seq_printf(s, " ");
 178                 if (!ret)
 179                         return TRACE_TYPE_PARTIAL_LINE;
 180         }
 181         ret = trace_seq_printf(s, "%d) ", cpu);
 182         if (!ret)
 183                 return TRACE_TYPE_PARTIAL_LINE;
 184
 185         return TRACE_TYPE_HANDLED;
 186 }
 187
 188 #define TRACE_GRAPH_PROCINFO_LENGTH     14
 189
 190 static enum print_line_t
 191 print_graph_proc(struct trace_seq *s, pid_t pid)
 192 {
 193         int i;
 194         int ret;
 195         int len;
 196         char comm[8];
 197         int spaces = 0;
 198         /* sign + log10(MAX_INT) + '\0' */
 199         char pid_str[11];
 200
 201         strncpy(comm, trace_find_cmdline(pid), 7);
 202         comm[7] = '\0';
 203         sprintf(pid_str, "%d", pid);
 204
 205         /* 1 stands for the "-" character */
 206         len = strlen(comm) + strlen(pid_str) + 1;
 207
 208         if (len < TRACE_GRAPH_PROCINFO_LENGTH)
 209                 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
 210
 211         /* First spaces to align center */
 212         for (i = 0; i < spaces / 2; i++) {
 213                 ret = trace_seq_printf(s, " ");
 214                 if (!ret)
 215                         return TRACE_TYPE_PARTIAL_LINE;
 216         }
 217
 218         ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
 219         if (!ret)
 220                 return TRACE_TYPE_PARTIAL_LINE;
 221
 222         /* Last spaces to align center */
 223         for (i = 0; i < spaces - (spaces / 2); i++) {
 224                 ret = trace_seq_printf(s, " ");
 225                 if (!ret)
 226                         return TRACE_TYPE_PARTIAL_LINE;
 227         }
 228         return TRACE_TYPE_HANDLED;
 229 }
 230
 231
 232 /* If the pid changed since the last trace, output this event */
 233 static enum print_line_t
 234 verif_pid(struct trace_seq *s, pid_t pid, int cpu, pid_t *last_pids_cpu)
 235 {
 236         pid_t prev_pid;
 237         pid_t *last_pid;
 238         int ret;
 239
 240         if (!last_pids_cpu)
 241                 return TRACE_TYPE_HANDLED;
 242
 243         last_pid = per_cpu_ptr(last_pids_cpu, cpu);
 244
 245         if (*last_pid == pid)
 246                 return TRACE_TYPE_HANDLED;
 247
 248         prev_pid = *last_pid;
 249         *last_pid = pid;
 250
 251         if (prev_pid == -1)
 252                 return TRACE_TYPE_HANDLED;
 253 /*
 254  * Context-switch trace line:
 255
 256  ------------------------------------------
 257  | 1)  migration/0--1  =>  sshd-1755
 258  ------------------------------------------
 259
 260  */
 261         ret = trace_seq_printf(s,
 262                 " ------------------------------------------\n");
 263         if (!ret)
 264                 return TRACE_TYPE_PARTIAL_LINE;
 265
 266         ret = print_graph_cpu(s, cpu);
 267         if (ret == TRACE_TYPE_PARTIAL_LINE)
 268                 return TRACE_TYPE_PARTIAL_LINE;
 269
 270         ret = print_graph_proc(s, prev_pid);
 271         if (ret == TRACE_TYPE_PARTIAL_LINE)
 272                 return TRACE_TYPE_PARTIAL_LINE;
 273
 274         ret = trace_seq_printf(s, " => ");
 275         if (!ret)
 276                 return TRACE_TYPE_PARTIAL_LINE;
 277
 278         ret = print_graph_proc(s, pid);
 279         if (ret == TRACE_TYPE_PARTIAL_LINE)
 280                 return TRACE_TYPE_PARTIAL_LINE;
 281
 282         ret = trace_seq_printf(s,
 283                 "\n ------------------------------------------\n\n");
 284         if (!ret)
 285                 return TRACE_TYPE_PARTIAL_LINE;
 286
 287         return TRACE_TYPE_HANDLED;
 288 }
 289
 290 static struct ftrace_graph_ret_entry *
 291 get_return_for_leaf(struct trace_iterator *iter,
 292                 struct ftrace_graph_ent_entry *curr)
 293 {
 294         struct ring_buffer_iter *ring_iter;
 295         struct ring_buffer_event *event;
 296         struct ftrace_graph_ret_entry *next;
 297
 298         ring_iter = iter->buffer_iter[iter->cpu];
 299
 300         /* First peek to compare current entry and the next one */
 301         if (ring_iter)
 302                 event = ring_buffer_iter_peek(ring_iter, NULL);
 303         else {
 304         /* We need to consume the current entry to see the next one */
 305                 ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL);
 306                 event = ring_buffer_peek(iter->tr->buffer, iter->cpu,
 307                                         NULL);
 308         }
 309
 310         if (!event)
 311                 return NULL;
 312
 313         next = ring_buffer_event_data(event);
 314
 315         if (next->ent.type != TRACE_GRAPH_RET)
 316                 return NULL;
 317
 318         if (curr->ent.pid != next->ent.pid ||
 319                         curr->graph_ent.func != next->ret.func)
 320                 return NULL;
 321
 322         /* this is a leaf, now advance the iterator */
 323         if (ring_iter)
 324                 ring_buffer_read(ring_iter, NULL);
 325
 326         return next;
 327 }
 328
 329 /* Signal a overhead of time execution to the output */
 330 static int
 331 print_graph_overhead(unsigned long long duration, struct trace_seq *s)
 332 {
 333         /* If duration disappear, we don't need anything */
 334         if (!(tracer_flags.val & TRACE_GRAPH_PRINT_DURATION))
 335                 return 1;
 336
 337         /* Non nested entry or return */
 338         if (duration == -1)
 339                 return trace_seq_printf(s, "  ");
 340
 341         if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
 342                 /* Duration exceeded 100 msecs */
 343                 if (duration > 100000ULL)
 344                         return trace_seq_printf(s, "! ");
 345
 346                 /* Duration exceeded 10 msecs */
 347                 if (duration > 10000ULL)
 348                         return trace_seq_printf(s, "+ ");
 349         }
 350
 351         return trace_seq_printf(s, "  ");
 352 }
 353
 354 static enum print_line_t
 355 print_graph_irq(struct trace_seq *s, unsigned long addr,
 356                 enum trace_type type, int cpu, pid_t pid)
 357 {
 358         int ret;
 359
 360         if (addr < (unsigned long)__irqentry_text_start ||
 361                 addr >= (unsigned long)__irqentry_text_end)
 362                 return TRACE_TYPE_UNHANDLED;
 363
 364         /* Cpu */
 365         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
 366                 ret = print_graph_cpu(s, cpu);
 367                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 368                         return TRACE_TYPE_PARTIAL_LINE;
 369         }
 370         /* Proc */
 371         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
 372                 ret = print_graph_proc(s, pid);
 373                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 374                         return TRACE_TYPE_PARTIAL_LINE;
 375                 ret = trace_seq_printf(s, " | ");
 376                 if (!ret)
 377                         return TRACE_TYPE_PARTIAL_LINE;
 378         }
 379
 380         /* No overhead */
 381         ret = print_graph_overhead(-1, s);
 382         if (!ret)
 383                 return TRACE_TYPE_PARTIAL_LINE;
 384
 385         if (type == TRACE_GRAPH_ENT)
 386                 ret = trace_seq_printf(s, "==========>");
 387         else
 388                 ret = trace_seq_printf(s, "<==========");
 389
 390         if (!ret)
 391                 return TRACE_TYPE_PARTIAL_LINE;
 392
 393         /* Don't close the duration column if haven't one */
 394         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 395                 trace_seq_printf(s, " |");
 396         ret = trace_seq_printf(s, "\n");
 397
 398         if (!ret)
 399                 return TRACE_TYPE_PARTIAL_LINE;
 400         return TRACE_TYPE_HANDLED;
 401 }
 402
 403 static enum print_line_t
 404 print_graph_duration(unsigned long long duration, struct trace_seq *s)
 405 {
 406         unsigned long nsecs_rem = do_div(duration, 1000);
 407         /* log10(ULONG_MAX) + '\0' */
 408         char msecs_str[21];
 409         char nsecs_str[5];
 410         int ret, len;
 411         int i;
 412
 413         sprintf(msecs_str, "%lu", (unsigned long) duration);
 414
 415         /* Print msecs */
 416         ret = trace_seq_printf(s, "%s", msecs_str);
 417         if (!ret)
 418                 return TRACE_TYPE_PARTIAL_LINE;
 419
 420         len = strlen(msecs_str);
 421
 422         /* Print nsecs (we don't want to exceed 7 numbers) */
 423         if (len < 7) {
 424                 snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem);
 425                 ret = trace_seq_printf(s, ".%s", nsecs_str);
 426                 if (!ret)
 427                         return TRACE_TYPE_PARTIAL_LINE;
 428                 len += strlen(nsecs_str);
 429         }
 430
 431         ret = trace_seq_printf(s, " us ");
 432         if (!ret)
 433                 return TRACE_TYPE_PARTIAL_LINE;
 434
 435         /* Print remaining spaces to fit the row's width */
 436         for (i = len; i < 7; i++) {
 437                 ret = trace_seq_printf(s, " ");
 438                 if (!ret)
 439                         return TRACE_TYPE_PARTIAL_LINE;
 440         }
 441
 442         ret = trace_seq_printf(s, "|  ");
 443         if (!ret)
 444                 return TRACE_TYPE_PARTIAL_LINE;
 445         return TRACE_TYPE_HANDLED;
 446
 447 }
 448
 449 static int print_graph_abs_time(u64 t, struct trace_seq *s)
 450 {
 451         unsigned long usecs_rem;
 452
 453         usecs_rem = do_div(t, 1000000000);
 454         usecs_rem /= 1000;
 455
 456         return trace_seq_printf(s, "%5lu.%06lu |  ",
 457                         (unsigned long)t, usecs_rem);
 458 }
 459
 460 /* Case of a leaf function on its call entry */
 461 static enum print_line_t
 462 print_graph_entry_leaf(struct trace_iterator *iter,
 463                 struct ftrace_graph_ent_entry *entry,
 464                 struct ftrace_graph_ret_entry *ret_entry, struct trace_seq *s)
 465 {
 466         struct ftrace_graph_ret *graph_ret;
 467         struct ftrace_graph_ent *call;
 468         unsigned long long duration;
 469         int ret;
 470         int i;
 471
 472         graph_ret = &ret_entry->ret;
 473         call = &entry->graph_ent;
 474         duration = graph_ret->rettime - graph_ret->calltime;
 475
 476         /* Overhead */
 477         ret = print_graph_overhead(duration, s);
 478         if (!ret)
 479                 return TRACE_TYPE_PARTIAL_LINE;
 480
 481         /* Duration */
 482         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 483                 ret = print_graph_duration(duration, s);
 484                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 485                         return TRACE_TYPE_PARTIAL_LINE;
 486         }
 487
 488         /* Function */
 489         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 490                 ret = trace_seq_printf(s, " ");
 491                 if (!ret)
 492                         return TRACE_TYPE_PARTIAL_LINE;
 493         }
 494
 495         ret = seq_print_ip_sym(s, call->func, 0);
 496         if (!ret)
 497                 return TRACE_TYPE_PARTIAL_LINE;
 498
 499         ret = trace_seq_printf(s, "();\n");
 500         if (!ret)
 501                 return TRACE_TYPE_PARTIAL_LINE;
 502
 503         return TRACE_TYPE_HANDLED;
 504 }
 505
 506 static enum print_line_t
 507 print_graph_entry_nested(struct ftrace_graph_ent_entry *entry,
 508                         struct trace_seq *s, pid_t pid, int cpu)
 509 {
 510         int i;
 511         int ret;
 512         struct ftrace_graph_ent *call = &entry->graph_ent;
 513
 514         /* No overhead */
 515         ret = print_graph_overhead(-1, s);
 516         if (!ret)
 517                 return TRACE_TYPE_PARTIAL_LINE;
 518
 519         /* No time */
 520         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 521                 ret = trace_seq_printf(s, "            |  ");
 522                 if (!ret)
 523                         return TRACE_TYPE_PARTIAL_LINE;
 524         }
 525
 526         /* Function */
 527         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 528                 ret = trace_seq_printf(s, " ");
 529                 if (!ret)
 530                         return TRACE_TYPE_PARTIAL_LINE;
 531         }
 532
 533         ret = seq_print_ip_sym(s, call->func, 0);
 534         if (!ret)
 535                 return TRACE_TYPE_PARTIAL_LINE;
 536
 537         ret = trace_seq_printf(s, "() {\n");
 538         if (!ret)
 539                 return TRACE_TYPE_PARTIAL_LINE;
 540
 541         /*
 542          * we already consumed the current entry to check the next one
 543          * and see if this is a leaf.
 544          */
 545         return TRACE_TYPE_NO_CONSUME;
 546 }
 547
 548 static enum print_line_t
 549 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
 550                         struct trace_iterator *iter)
 551 {
 552         int ret;
 553         int cpu = iter->cpu;
 554         pid_t *last_entry = iter->private;
 555         struct trace_entry *ent = iter->ent;
 556         struct ftrace_graph_ent *call = &field->graph_ent;
 557         struct ftrace_graph_ret_entry *leaf_ret;
 558
 559         /* Pid */
 560         if (verif_pid(s, ent->pid, cpu, last_entry) == TRACE_TYPE_PARTIAL_LINE)
 561                 return TRACE_TYPE_PARTIAL_LINE;
 562
 563         /* Interrupt */
 564         ret = print_graph_irq(s, call->func, TRACE_GRAPH_ENT, cpu, ent->pid);
 565         if (ret == TRACE_TYPE_PARTIAL_LINE)
 566                 return TRACE_TYPE_PARTIAL_LINE;
 567
 568         /* Absolute time */
 569         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
 570                 ret = print_graph_abs_time(iter->ts, s);
 571                 if (!ret)
 572                         return TRACE_TYPE_PARTIAL_LINE;
 573         }
 574
 575         /* Cpu */
 576         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
 577                 ret = print_graph_cpu(s, cpu);
 578                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 579                         return TRACE_TYPE_PARTIAL_LINE;
 580         }
 581
 582         /* Proc */
 583         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
 584                 ret = print_graph_proc(s, ent->pid);
 585                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 586                         return TRACE_TYPE_PARTIAL_LINE;
 587
 588                 ret = trace_seq_printf(s, " | ");
 589                 if (!ret)
 590                         return TRACE_TYPE_PARTIAL_LINE;
 591         }
 592
 593         leaf_ret = get_return_for_leaf(iter, field);
 594         if (leaf_ret)
 595                 return print_graph_entry_leaf(iter, field, leaf_ret, s);
 596         else
 597                 return print_graph_entry_nested(field, s, iter->ent->pid, cpu);
 598
 599 }
 600
 601 static enum print_line_t
 602 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 603                    struct trace_entry *ent, struct trace_iterator *iter)
 604 {
 605         int i;
 606         int ret;
 607         int cpu = iter->cpu;
 608         pid_t *last_pid = iter->private;
 609         unsigned long long duration = trace->rettime - trace->calltime;
 610
 611         /* Pid */
 612         if (verif_pid(s, ent->pid, cpu, last_pid) == TRACE_TYPE_PARTIAL_LINE)
 613                 return TRACE_TYPE_PARTIAL_LINE;
 614
 615         /* Absolute time */
 616         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
 617                 ret = print_graph_abs_time(iter->ts, s);
 618                 if (!ret)
 619                         return TRACE_TYPE_PARTIAL_LINE;
 620         }
 621
 622         /* Cpu */
 623         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
 624                 ret = print_graph_cpu(s, cpu);
 625                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 626                         return TRACE_TYPE_PARTIAL_LINE;
 627         }
 628
 629         /* Proc */
 630         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
 631                 ret = print_graph_proc(s, ent->pid);
 632                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 633                         return TRACE_TYPE_PARTIAL_LINE;
 634
 635                 ret = trace_seq_printf(s, " | ");
 636                 if (!ret)
 637                         return TRACE_TYPE_PARTIAL_LINE;
 638         }
 639
 640         /* Overhead */
 641         ret = print_graph_overhead(duration, s);
 642         if (!ret)
 643                 return TRACE_TYPE_PARTIAL_LINE;
 644
 645         /* Duration */
 646         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 647                 ret = print_graph_duration(duration, s);
 648                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 649                         return TRACE_TYPE_PARTIAL_LINE;
 650         }
 651
 652         /* Closing brace */
 653         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
 654                 ret = trace_seq_printf(s, " ");
 655                 if (!ret)
 656                         return TRACE_TYPE_PARTIAL_LINE;
 657         }
 658
 659         ret = trace_seq_printf(s, "}\n");
 660         if (!ret)
 661                 return TRACE_TYPE_PARTIAL_LINE;
 662
 663         /* Overrun */
 664         if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) {
 665                 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
 666                                         trace->overrun);
 667                 if (!ret)
 668                         return TRACE_TYPE_PARTIAL_LINE;
 669         }
 670
 671         ret = print_graph_irq(s, trace->func, TRACE_GRAPH_RET, cpu, ent->pid);
 672         if (ret == TRACE_TYPE_PARTIAL_LINE)
 673                 return TRACE_TYPE_PARTIAL_LINE;
 674
 675         return TRACE_TYPE_HANDLED;
 676 }
 677
 678 static enum print_line_t
 679 print_graph_comment(struct print_entry *trace, struct trace_seq *s,
 680                    struct trace_entry *ent, struct trace_iterator *iter)
 681 {
 682         int i;
 683         int ret;
 684         int cpu = iter->cpu;
 685         pid_t *last_pid = iter->private;
 686
 687         /* Absolute time */
 688         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
 689                 ret = print_graph_abs_time(iter->ts, s);
 690                 if (!ret)
 691                         return TRACE_TYPE_PARTIAL_LINE;
 692         }
 693
 694         /* Pid */
 695         if (verif_pid(s, ent->pid, cpu, last_pid) == TRACE_TYPE_PARTIAL_LINE)
 696                 return TRACE_TYPE_PARTIAL_LINE;
 697
 698         /* Cpu */
 699         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
 700                 ret = print_graph_cpu(s, cpu);
 701                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 702                         return TRACE_TYPE_PARTIAL_LINE;
 703         }
 704
 705         /* Proc */
 706         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
 707                 ret = print_graph_proc(s, ent->pid);
 708                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 709                         return TRACE_TYPE_PARTIAL_LINE;
 710
 711                 ret = trace_seq_printf(s, " | ");
 712                 if (!ret)
 713                         return TRACE_TYPE_PARTIAL_LINE;
 714         }
 715
 716         /* No overhead */
 717         ret = print_graph_overhead(-1, s);
 718         if (!ret)
 719                 return TRACE_TYPE_PARTIAL_LINE;
 720
 721         /* No time */
 722         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 723                 ret = trace_seq_printf(s, "            |  ");
 724                 if (!ret)
 725                         return TRACE_TYPE_PARTIAL_LINE;
 726         }
 727
 728         /* Indentation */
 729         if (trace->depth > 0)
 730                 for (i = 0; i < (trace->depth + 1) * TRACE_GRAPH_INDENT; i++) {
 731                         ret = trace_seq_printf(s, " ");
 732                         if (!ret)
 733                                 return TRACE_TYPE_PARTIAL_LINE;
 734                 }
 735
 736         /* The comment */
 737         ret = trace_seq_printf(s, "/* %s", trace->buf);
 738         if (!ret)
 739                 return TRACE_TYPE_PARTIAL_LINE;
 740
 741         /* Strip ending newline */
 742         if (s->buffer[s->len - 1] == '\n') {
 743                 s->buffer[s->len - 1] = '\0';
 744                 s->len--;
 745         }
 746
 747         ret = trace_seq_printf(s, " */\n");
 748         if (!ret)
 749                 return TRACE_TYPE_PARTIAL_LINE;
 750
 751         return TRACE_TYPE_HANDLED;
 752 }
 753
 754
 755 enum print_line_t
 756 print_graph_function(struct trace_iterator *iter)
 757 {
 758         struct trace_seq *s = &iter->seq;
 759         struct trace_entry *entry = iter->ent;
 760
 761         switch (entry->type) {
 762         case TRACE_GRAPH_ENT: {
 763                 struct ftrace_graph_ent_entry *field;
 764                 trace_assign_type(field, entry);
 765                 return print_graph_entry(field, s, iter);
 766         }
 767         case TRACE_GRAPH_RET: {
 768                 struct ftrace_graph_ret_entry *field;
 769                 trace_assign_type(field, entry);
 770                 return print_graph_return(&field->ret, s, entry, iter);
 771         }
 772         case TRACE_PRINT: {
 773                 struct print_entry *field;
 774                 trace_assign_type(field, entry);
 775                 return print_graph_comment(field, s, entry, iter);
 776         }
 777         default:
 778                 return TRACE_TYPE_UNHANDLED;
 779         }
 780 }
 781
 782 static void print_graph_headers(struct seq_file *s)
 783 {
 784         /* 1st line */
 785         seq_printf(s, "# ");
 786         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
 787                 seq_printf(s, "     TIME       ");
 788         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
 789                 seq_printf(s, "CPU");
 790         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
 791                 seq_printf(s, "  TASK/PID      ");
 792         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 793                 seq_printf(s, "  DURATION   ");
 794         seq_printf(s, "               FUNCTION CALLS\n");
 795
 796         /* 2nd line */
 797         seq_printf(s, "# ");
 798         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
 799                 seq_printf(s, "      |         ");
 800         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
 801                 seq_printf(s, "|  ");
 802         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
 803                 seq_printf(s, "  |    |        ");
 804         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 805                 seq_printf(s, "   |   |      ");
 806         seq_printf(s, "               |   |   |   |\n");
 807 }
 808
 809 static void graph_trace_open(struct trace_iterator *iter)
 810 {
 811         /* pid on the last trace processed */
 812         pid_t *last_pid = alloc_percpu(pid_t);
 813         int cpu;
 814
 815         if (!last_pid)
 816                 pr_warning("function graph tracer: not enough memory\n");
 817         else
 818                 for_each_possible_cpu(cpu) {
 819                         pid_t *pid = per_cpu_ptr(last_pid, cpu);
 820                         *pid = -1;
 821                 }
 822
 823         iter->private = last_pid;
 824 }
 825
 826 static void graph_trace_close(struct trace_iterator *iter)
 827 {
 828         percpu_free(iter->private);
 829 }
 830
 831 static struct tracer graph_trace __read_mostly = {
 832         .name           = "function_graph",
 833         .open           = graph_trace_open,
 834         .close          = graph_trace_close,
 835         .wait_pipe      = poll_wait_pipe,
 836         .init           = graph_trace_init,
 837         .reset          = graph_trace_reset,
 838         .print_line     = print_graph_function,
 839         .print_header   = print_graph_headers,
 840         .flags          = &tracer_flags,
 841 #ifdef CONFIG_FTRACE_SELFTEST
 842         .selftest       = trace_selftest_startup_function_graph,
 843 #endif
 844 };
 845
 846 static __init int init_graph_trace(void)
 847 {
 848         return register_tracer(&graph_trace);
 849 }
 850
 851 device_initcall(init_graph_trace);