/* * * Function graph tracer. * Copyright (c) 2008-2009 Frederic Weisbecker * Mostly borrowed from function tracer which * is Copyright (c) Steven Rostedt * */ #include #include #include #include #include "trace.h" #include "trace_output.h" struct fgraph_data { pid_t last_pid; int depth; }; #define TRACE_GRAPH_INDENT 2 /* Flag options */ #define TRACE_GRAPH_PRINT_OVERRUN 0x1 #define TRACE_GRAPH_PRINT_CPU 0x2 #define TRACE_GRAPH_PRINT_OVERHEAD 0x4 #define TRACE_GRAPH_PRINT_PROC 0x8 #define TRACE_GRAPH_PRINT_DURATION 0x10 #define TRACE_GRAPH_PRINT_ABS_TIME 0X20 static struct tracer_opt trace_opts[] = { /* Display overruns? (for self-debug purpose) */ { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) }, /* Display CPU ? */ { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) }, /* Display Overhead ? */ { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) }, /* Display proc name/pid */ { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) }, /* Display duration of execution */ { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) }, /* Display absolute time of an entry */ { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) }, { } /* Empty entry */ }; static struct tracer_flags tracer_flags = { /* Don't display overruns and proc by default */ .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD | TRACE_GRAPH_PRINT_DURATION, .opts = trace_opts }; static struct trace_array *graph_array; /* Add a function return address to the trace stack on thread info.*/ int ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth, unsigned long frame_pointer) { unsigned long long calltime; int index; if (!current->ret_stack) return -EBUSY; /* * We must make sure the ret_stack is tested before we read * anything else. */ smp_rmb(); /* The return trace stack is full */ if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) { atomic_inc(¤t->trace_overrun); return -EBUSY; } calltime = trace_clock_local(); index = ++current->curr_ret_stack; barrier(); current->ret_stack[index].ret = ret; current->ret_stack[index].func = func; current->ret_stack[index].calltime = calltime; current->ret_stack[index].subtime = 0; current->ret_stack[index].fp = frame_pointer; *depth = index; return 0; } /* Retrieve a function return address to the trace stack on thread info.*/ static void ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret, unsigned long frame_pointer) { int index; index = current->curr_ret_stack; if (unlikely(index < 0)) { ftrace_graph_stop(); WARN_ON(1); /* Might as well panic, otherwise we have no where to go */ *ret = (unsigned long)panic; return; } #ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST /* * The arch may choose to record the frame pointer used * and check it here to make sure that it is what we expect it * to be. If gcc does not set the place holder of the return * address in the frame pointer, and does a copy instead, then * the function graph trace will fail. This test detects this * case. * * Currently, x86_32 with optimize for size (-Os) makes the latest * gcc do the above. */ if (unlikely(current->ret_stack[index].fp != frame_pointer)) { ftrace_graph_stop(); WARN(1, "Bad frame pointer: expected %lx, received %lx\n" " from func %pF return to %lx\n", current->ret_stack[index].fp, frame_pointer, (void *)current->ret_stack[index].func, current->ret_stack[index].ret); *ret = (unsigned long)panic; return; } #endif *ret = current->ret_stack[index].ret; trace->func = current->ret_stack[index].func; trace->calltime = current->ret_stack[index].calltime; trace->overrun = atomic_read(¤t->trace_overrun); trace->depth = index; } /* * Send the trace to the ring-buffer. * @return the original return address. */ unsigned long ftrace_return_to_handler(unsigned long frame_pointer) { struct ftrace_graph_ret trace; unsigned long ret; ftrace_pop_return_trace(&trace, &ret, frame_pointer); trace.rettime = trace_clock_local(); ftrace_graph_return(&trace); barrier(); current->curr_ret_stack--; if (unlikely(!ret)) { ftrace_graph_stop(); WARN_ON(1); /* Might as well panic. What else to do? */ ret = (unsigned long)panic; } return ret; } static int __trace_graph_entry(struct trace_array *tr, struct ftrace_graph_ent *trace, unsigned long flags, int pc) { struct ftrace_event_call *call = &event_funcgraph_entry; struct ring_buffer_event *event; struct ring_buffer *buffer = tr->buffer; struct ftrace_graph_ent_entry *entry; if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled)))) return 0; event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT, sizeof(*entry), flags, pc); if (!event) return 0; entry = ring_buffer_event_data(event); entry->graph_ent = *trace; if (!filter_current_check_discard(buffer, call, entry, event)) ring_buffer_unlock_commit(buffer, event); return 1; } int trace_graph_entry(struct ftrace_graph_ent *trace) { struct trace_array *tr = graph_array; struct trace_array_cpu *data; unsigned long flags; long disabled; int ret; int cpu; int pc; if (unlikely(!tr)) return 0; if (!ftrace_trace_task(current)) return 0; if (!ftrace_graph_addr(trace->func)) return 0; local_irq_save(flags); cpu = raw_smp_processor_id(); data = tr->data[cpu]; disabled = atomic_inc_return(&data->disabled); if (likely(disabled == 1)) { pc = preempt_count(); ret = __trace_graph_entry(tr, trace, flags, pc); } else { ret = 0; } /* Only do the atomic if it is not already set */ if (!test_tsk_trace_graph(current)) set_tsk_trace_graph(current); atomic_dec(&data->disabled); local_irq_restore(flags); return ret; } static void __trace_graph_return(struct trace_array *tr, struct ftrace_graph_ret *trace, unsigned long flags, int pc) { struct ftrace_event_call *call = &event_funcgraph_exit; struct ring_buffer_event *event; struct ring_buffer *buffer = tr->buffer; struct ftrace_graph_ret_entry *entry; if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled)))) return; event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET, sizeof(*entry), flags, pc); if (!event) return; entry = ring_buffer_event_data(event); entry->ret = *trace; if (!filter_current_check_discard(buffer, call, entry, event)) ring_buffer_unlock_commit(buffer, event); } void trace_graph_return(struct ftrace_graph_ret *trace) { struct trace_array *tr = graph_array; struct trace_array_cpu *data; unsigned long flags; long disabled; int cpu; int pc; local_irq_save(flags); cpu = raw_smp_processor_id(); data = tr->data[cpu]; disabled = atomic_inc_return(&data->disabled); if (likely(disabled == 1)) { pc = preempt_count(); __trace_graph_return(tr, trace, flags, pc); } if (!trace->depth) clear_tsk_trace_graph(current); atomic_dec(&data->disabled); local_irq_restore(flags); } static int graph_trace_init(struct trace_array *tr) { int ret; graph_array = tr; ret = register_ftrace_graph(&trace_graph_return, &trace_graph_entry); if (ret) return ret; tracing_start_cmdline_record(); return 0; } void set_graph_array(struct trace_array *tr) { graph_array = tr; } static void graph_trace_reset(struct trace_array *tr) { tracing_stop_cmdline_record(); unregister_ftrace_graph(); } static int max_bytes_for_cpu; static enum print_line_t print_graph_cpu(struct trace_seq *s, int cpu) { int ret; /* * Start with a space character - to make it stand out * to the right a bit when trace output is pasted into * email: */ ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu); if (!ret) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } #define TRACE_GRAPH_PROCINFO_LENGTH 14 static enum print_line_t print_graph_proc(struct trace_seq *s, pid_t pid) { char comm[TASK_COMM_LEN]; /* sign + log10(MAX_INT) + '\0' */ char pid_str[11]; int spaces = 0; int ret; int len; int i; trace_find_cmdline(pid, comm); comm[7] = '\0'; sprintf(pid_str, "%d", pid); /* 1 stands for the "-" character */ len = strlen(comm) + strlen(pid_str) + 1; if (len < TRACE_GRAPH_PROCINFO_LENGTH) spaces = TRACE_GRAPH_PROCINFO_LENGTH - len; /* First spaces to align center */ for (i = 0; i < spaces / 2; i++) { ret = trace_seq_printf(s, " "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } ret = trace_seq_printf(s, "%s-%s", comm, pid_str); if (!ret) return TRACE_TYPE_PARTIAL_LINE; /* Last spaces to align center */ for (i = 0; i < spaces - (spaces / 2); i++) { ret = trace_seq_printf(s, " "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } return TRACE_TYPE_HANDLED; } static enum print_line_t print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry) { int hardirq, softirq; hardirq = entry->flags & TRACE_FLAG_HARDIRQ; softirq = entry->flags & TRACE_FLAG_SOFTIRQ; if (!trace_seq_printf(s, " %c%c%c", (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' : (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' : '.', (entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.', (hardirq && softirq) ? 'H' : hardirq ? 'h' : softirq ? 's' : '.')) return 0; if (entry->preempt_count) return trace_seq_printf(s, "%x", entry->preempt_count); return trace_seq_puts(s, "."); } /* If the pid changed since the last trace, output this event */ static enum print_line_t verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data) { pid_t prev_pid; pid_t *last_pid; int ret; if (!data) return TRACE_TYPE_HANDLED; last_pid = &(per_cpu_ptr(data, cpu)->last_pid); if (*last_pid == pid) return TRACE_TYPE_HANDLED; prev_pid = *last_pid; *last_pid = pid; if (prev_pid == -1) return TRACE_TYPE_HANDLED; /* * Context-switch trace line: ------------------------------------------ | 1) migration/0--1 => sshd-1755 ------------------------------------------ */ ret = trace_seq_printf(s, " ------------------------------------------\n"); if (!ret) return TRACE_TYPE_PARTIAL_LINE; ret = print_graph_cpu(s, cpu); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; ret = print_graph_proc(s, prev_pid); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; ret = trace_seq_printf(s, " => "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; ret = print_graph_proc(s, pid); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; ret = trace_seq_printf(s, "\n ------------------------------------------\n\n"); if (!ret) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } static struct ftrace_graph_ret_entry * get_return_for_leaf(struct trace_iterator *iter, struct ftrace_graph_ent_entry *curr) { struct ring_buffer_iter *ring_iter; struct ring_buffer_event *event; struct ftrace_graph_ret_entry *next; ring_iter = iter->buffer_iter[iter->cpu]; /* First peek to compare current entry and the next one */ if (ring_iter) event = ring_buffer_iter_peek(ring_iter, NULL); else { /* We need to consume the current entry to see the next one */ ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL); event = ring_buffer_peek(iter->tr->buffer, iter->cpu, NULL); } if (!event) return NULL; next = ring_buffer_event_data(event); if (next->ent.type != TRACE_GRAPH_RET) return NULL; if (curr->ent.pid != next->ent.pid || curr->graph_ent.func != next->ret.func) return NULL; /* this is a leaf, now advance the iterator */ if (ring_iter) ring_buffer_read(ring_iter, NULL); return next; } /* Signal a overhead of time execution to the output */ static int print_graph_overhead(unsigned long long duration, struct trace_seq *s) { /* If duration disappear, we don't need anything */ if (!(tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)) return 1; /* Non nested entry or return */ if (duration == -1) return trace_seq_printf(s, " "); if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) { /* Duration exceeded 100 msecs */ if (duration > 100000ULL) return trace_seq_printf(s, "! "); /* Duration exceeded 10 msecs */ if (duration > 10000ULL) return trace_seq_printf(s, "+ "); } return trace_seq_printf(s, " "); } static int print_graph_abs_time(u64 t, struct trace_seq *s) { unsigned long usecs_rem; usecs_rem = do_div(t, NSEC_PER_SEC); usecs_rem /= 1000; return trace_seq_printf(s, "%5lu.%06lu | ", (unsigned long)t, usecs_rem); } static enum print_line_t print_graph_irq(struct trace_iterator *iter, unsigned long addr, enum trace_type type, int cpu, pid_t pid) { int ret; struct trace_seq *s = &iter->seq; if (addr < (unsigned long)__irqentry_text_start || addr >= (unsigned long)__irqentry_text_end) return TRACE_TYPE_UNHANDLED; /* Absolute time */ if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) { ret = print_graph_abs_time(iter->ts, s); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } /* Cpu */ if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) { ret = print_graph_cpu(s, cpu); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; } /* Proc */ if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) { ret = print_graph_proc(s, pid); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; ret = trace_seq_printf(s, " | "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } /* No overhead */ ret = print_graph_overhead(-1, s); if (!ret) return TRACE_TYPE_PARTIAL_LINE; if (type == TRACE_GRAPH_ENT) ret = trace_seq_printf(s, "==========>"); else ret = trace_seq_printf(s, "<=========="); if (!ret) return TRACE_TYPE_PARTIAL_LINE; /* Don't close the duration column if haven't one */ if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) trace_seq_printf(s, " |"); ret = trace_seq_printf(s, "\n"); if (!ret) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } enum print_line_t trace_print_graph_duration(unsigned long long duration, struct trace_seq *s) { unsigned long nsecs_rem = do_div(duration, 1000); /* log10(ULONG_MAX) + '\0' */ char msecs_str[21]; char nsecs_str[5]; int ret, len; int i; sprintf(msecs_str, "%lu", (unsigned long) duration); /* Print msecs */ ret = trace_seq_printf(s, "%s", msecs_str); if (!ret) return TRACE_TYPE_PARTIAL_LINE; len = strlen(msecs_str); /* Print nsecs (we don't want to exceed 7 numbers) */ if (len < 7) { snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem); ret = trace_seq_printf(s, ".%s", nsecs_str); if (!ret) return TRACE_TYPE_PARTIAL_LINE; len += strlen(nsecs_str); } ret = trace_seq_printf(s, " us "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; /* Print remaining spaces to fit the row's width */ for (i = len; i < 7; i++) { ret = trace_seq_printf(s, " "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } return TRACE_TYPE_HANDLED; } static enum print_line_t print_graph_duration(unsigned long long duration, struct trace_seq *s) { int ret; ret = trace_print_graph_duration(duration, s); if (ret != TRACE_TYPE_HANDLED) return ret; ret = trace_seq_printf(s, "| "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } /* Case of a leaf function on its call entry */ static enum print_line_t print_graph_entry_leaf(struct trace_iterator *iter, struct ftrace_graph_ent_entry *entry, struct ftrace_graph_ret_entry *ret_entry, struct trace_seq *s) { struct fgraph_data *data = iter->private; struct ftrace_graph_ret *graph_ret; struct ftrace_graph_ent *call; unsigned long long duration; int ret; int i; graph_ret = &ret_entry->ret; call = &entry->graph_ent; duration = graph_ret->rettime - graph_ret->calltime; if (data) { int cpu = iter->cpu; int *depth = &(per_cpu_ptr(data, cpu)->depth); /* * Comments display at + 1 to depth. Since * this is a leaf function, keep the comments * equal to this depth. */ *depth = call->depth - 1; } /* Overhead */ ret = print_graph_overhead(duration, s); if (!ret) return TRACE_TYPE_PARTIAL_LINE; /* Duration */ if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) { ret = print_graph_duration(duration, s); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; } /* Function */ for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) { ret = trace_seq_printf(s, " "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } ret = trace_seq_printf(s, "%pf();\n", (void *)call->func); if (!ret) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } static enum print_line_t print_graph_entry_nested(struct trace_iterator *iter, struct ftrace_graph_ent_entry *entry, struct trace_seq *s, int cpu) { struct ftrace_graph_ent *call = &entry->graph_ent; struct fgraph_data *data = iter->private; int ret; int i; if (data) { int cpu = iter->cpu; int *depth = &(per_cpu_ptr(data, cpu)->depth); *depth = call->depth; } /* No overhead */ ret = print_graph_overhead(-1, s); if (!ret) return TRACE_TYPE_PARTIAL_LINE; /* No time */ if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) { ret = trace_seq_printf(s, " | "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } /* Function */ for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) { ret = trace_seq_printf(s, " "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } ret = trace_seq_printf(s, "%pf() {\n", (void *)call->func); if (!ret) return TRACE_TYPE_PARTIAL_LINE; /* * we already consumed the current entry to check the next one * and see if this is a leaf. */ return TRACE_TYPE_NO_CONSUME; } static enum print_line_t print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s, int type, unsigned long addr) { struct fgraph_data *data = iter->private; struct trace_entry *ent = iter->ent; int cpu = iter->cpu; int ret; /* Pid */ if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; if (type) { /* Interrupt */ ret = print_graph_irq(iter, addr, type, cpu, ent->pid); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; } /* Absolute time */ if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) { ret = print_graph_abs_time(iter->ts, s); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } /* Cpu */ if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) { ret = print_graph_cpu(s, cpu); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; } /* Proc */ if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) { ret = print_graph_proc(s, ent->pid); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; ret = trace_seq_printf(s, " | "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } /* Latency format */ if (trace_flags & TRACE_ITER_LATENCY_FMT) { ret = print_graph_lat_fmt(s, ent); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; } return 0; } static enum print_line_t print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s, struct trace_iterator *iter) { int cpu = iter->cpu; struct ftrace_graph_ent *call = &field->graph_ent; struct ftrace_graph_ret_entry *leaf_ret; if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func)) return TRACE_TYPE_PARTIAL_LINE; leaf_ret = get_return_for_leaf(iter, field); if (leaf_ret) return print_graph_entry_leaf(iter, field, leaf_ret, s); else return print_graph_entry_nested(iter, field, s, cpu); } static enum print_line_t print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, struct trace_entry *ent, struct trace_iterator *iter) { unsigned long long duration = trace->rettime - trace->calltime; struct fgraph_data *data = iter->private; pid_t pid = ent->pid; int cpu = iter->cpu; int ret; int i; if (data) { int cpu = iter->cpu; int *depth = &(per_cpu_ptr(data, cpu)->depth); /* * Comments display at + 1 to depth. This is the * return from a function, we now want the comments * to display at the same level of the bracket. */ *depth = trace->depth - 1; } if (print_graph_prologue(iter, s, 0, 0)) return TRACE_TYPE_PARTIAL_LINE; /* Overhead */ ret = print_graph_overhead(duration, s); if (!ret) return TRACE_TYPE_PARTIAL_LINE; /* Duration */ if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) { ret = print_graph_duration(duration, s); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; } /* Closing brace */ for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) { ret = trace_seq_printf(s, " "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } ret = trace_seq_printf(s, "}\n"); if (!ret) return TRACE_TYPE_PARTIAL_LINE; /* Overrun */ if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) { ret = trace_seq_printf(s, " (Overruns: %lu)\n", trace->overrun); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, cpu, pid); if (ret == TRACE_TYPE_PARTIAL_LINE) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } static enum print_line_t print_graph_comment(struct trace_seq *s, struct trace_entry *ent, struct trace_iterator *iter) { unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK); struct fgraph_data *data = iter->private; struct trace_event *event; int depth = 0; int ret; int i; if (data) depth = per_cpu_ptr(data, iter->cpu)->depth; if (print_graph_prologue(iter, s, 0, 0)) return TRACE_TYPE_PARTIAL_LINE; /* No overhead */ ret = print_graph_overhead(-1, s); if (!ret) return TRACE_TYPE_PARTIAL_LINE; /* No time */ if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) { ret = trace_seq_printf(s, " | "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } /* Indentation */ if (depth > 0) for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) { ret = trace_seq_printf(s, " "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; } /* The comment */ ret = trace_seq_printf(s, "/* "); if (!ret) return TRACE_TYPE_PARTIAL_LINE; switch (iter->ent->type) { case TRACE_BPRINT: ret = trace_print_bprintk_msg_only(iter); if (ret != TRACE_TYPE_HANDLED) return ret; break; case TRACE_PRINT: ret = trace_print_printk_msg_only(iter); if (ret != TRACE_TYPE_HANDLED) return ret; break; default: event = ftrace_find_event(ent->type); if (!event) return TRACE_TYPE_UNHANDLED; ret = event->trace(iter, sym_flags); if (ret != TRACE_TYPE_HANDLED) return ret; } /* Strip ending newline */ if (s->buffer[s->len - 1] == '\n') { s->buffer[s->len - 1] = '\0'; s->len--; } ret = trace_seq_printf(s, " */\n"); if (!ret) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } enum print_line_t print_graph_function(struct trace_iterator *iter) { struct trace_entry *entry = iter->ent; struct trace_seq *s = &iter->seq; switch (entry->type) { case TRACE_GRAPH_ENT: { /* * print_graph_entry() may consume the current event, * thus @field may become invalid, so we need to save it. * sizeof(struct ftrace_graph_ent_entry) is very small, * it can be safely saved at the stack. */ struct ftrace_graph_ent_entry *field, saved; trace_assign_type(field, entry); saved = *field; return print_graph_entry(&saved, s, iter); } case TRACE_GRAPH_RET: { struct ftrace_graph_ret_entry *field; trace_assign_type(field, entry); return print_graph_return(&field->ret, s, entry, iter); } default: return print_graph_comment(s, entry, iter); } return TRACE_TYPE_HANDLED; } static void print_lat_header(struct seq_file *s) { static const char spaces[] = " " /* 16 spaces */ " " /* 4 spaces */ " "; /* 17 spaces */ int size = 0; if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) size += 16; if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) size += 4; if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) size += 17; seq_printf(s, "#%.*s _-----=> irqs-off \n", size, spaces); seq_printf(s, "#%.*s / _----=> need-resched \n", size, spaces); seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces); seq_printf(s, "#%.*s|| / _--=> preempt-depth \n", size, spaces); seq_printf(s, "#%.*s||| / \n", size, spaces); seq_printf(s, "#%.*s|||| \n", size, spaces); } static void print_graph_headers(struct seq_file *s) { int lat = trace_flags & TRACE_ITER_LATENCY_FMT; if (lat) print_lat_header(s); /* 1st line */ seq_printf(s, "#"); if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) seq_printf(s, " TIME "); if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) seq_printf(s, " CPU"); if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) seq_printf(s, " TASK/PID "); if (lat) seq_printf(s, "||||"); if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) seq_printf(s, " DURATION "); seq_printf(s, " FUNCTION CALLS\n"); /* 2nd line */ seq_printf(s, "#"); if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) seq_printf(s, " | "); if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) seq_printf(s, " | "); if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) seq_printf(s, " | | "); if (lat) seq_printf(s, "||||"); if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) seq_printf(s, " | | "); seq_printf(s, " | | | |\n"); } static void graph_trace_open(struct trace_iterator *iter) { /* pid and depth on the last trace processed */ struct fgraph_data *data = alloc_percpu(struct fgraph_data); int cpu; if (!data) pr_warning("function graph tracer: not enough memory\n"); else for_each_possible_cpu(cpu) { pid_t *pid = &(per_cpu_ptr(data, cpu)->last_pid); int *depth = &(per_cpu_ptr(data, cpu)->depth); *pid = -1; *depth = 0; } iter->private = data; } static void graph_trace_close(struct trace_iterator *iter) { free_percpu(iter->private); } static struct tracer graph_trace __read_mostly = { .name = "function_graph", .open = graph_trace_open, .close = graph_trace_close, .wait_pipe = poll_wait_pipe, .init = graph_trace_init, .reset = graph_trace_reset, .print_line = print_graph_function, .print_header = print_graph_headers, .flags = &tracer_flags, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_function_graph, #endif }; static __init int init_graph_trace(void) { max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1); return register_tracer(&graph_trace); } device_initcall(init_graph_trace);