1 // SPDX-License-Identifier: GPL-2.0
4 * Function graph tracer.
5 * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
6 * Mostly borrowed from function tracer which
7 * is Copyright (c) Steven Rostedt <srostedt@redhat.com>
10 #include <linux/uaccess.h>
11 #include <linux/ftrace.h>
12 #include <linux/interrupt.h>
13 #include <linux/slab.h>
17 #include "trace_output.h"
19 /* When set, irq functions will be ignored */
20 static int ftrace_graph_skip_irqs
;
22 struct fgraph_cpu_data
{
27 unsigned long enter_funcs
[FTRACE_RETFUNC_DEPTH
];
31 struct fgraph_cpu_data __percpu
*cpu_data
;
33 /* Place to preserve last processed entry. */
34 struct ftrace_graph_ent_entry ent
;
35 struct ftrace_graph_ret_entry ret
;
40 #define TRACE_GRAPH_INDENT 2
42 unsigned int fgraph_max_depth
;
44 static struct tracer_opt trace_opts
[] = {
45 /* Display overruns? (for self-debug purpose) */
46 { TRACER_OPT(funcgraph
-overrun
, TRACE_GRAPH_PRINT_OVERRUN
) },
48 { TRACER_OPT(funcgraph
-cpu
, TRACE_GRAPH_PRINT_CPU
) },
49 /* Display Overhead ? */
50 { TRACER_OPT(funcgraph
-overhead
, TRACE_GRAPH_PRINT_OVERHEAD
) },
51 /* Display proc name/pid */
52 { TRACER_OPT(funcgraph
-proc
, TRACE_GRAPH_PRINT_PROC
) },
53 /* Display duration of execution */
54 { TRACER_OPT(funcgraph
-duration
, TRACE_GRAPH_PRINT_DURATION
) },
55 /* Display absolute time of an entry */
56 { TRACER_OPT(funcgraph
-abstime
, TRACE_GRAPH_PRINT_ABS_TIME
) },
57 /* Display interrupts */
58 { TRACER_OPT(funcgraph
-irqs
, TRACE_GRAPH_PRINT_IRQS
) },
59 /* Display function name after trailing } */
60 { TRACER_OPT(funcgraph
-tail
, TRACE_GRAPH_PRINT_TAIL
) },
61 /* Include sleep time (scheduled out) between entry and return */
62 { TRACER_OPT(sleep
-time
, TRACE_GRAPH_SLEEP_TIME
) },
64 #ifdef CONFIG_FUNCTION_PROFILER
65 /* Include time within nested functions */
66 { TRACER_OPT(graph
-time
, TRACE_GRAPH_GRAPH_TIME
) },
72 static struct tracer_flags tracer_flags
= {
73 /* Don't display overruns, proc, or tail by default */
74 .val
= TRACE_GRAPH_PRINT_CPU
| TRACE_GRAPH_PRINT_OVERHEAD
|
75 TRACE_GRAPH_PRINT_DURATION
| TRACE_GRAPH_PRINT_IRQS
|
76 TRACE_GRAPH_SLEEP_TIME
| TRACE_GRAPH_GRAPH_TIME
,
80 static struct trace_array
*graph_array
;
83 * DURATION column is being also used to display IRQ signs,
84 * following values are used by print_graph_irq and others
85 * to fill in space into DURATION column.
88 FLAGS_FILL_FULL
= 1 << TRACE_GRAPH_PRINT_FILL_SHIFT
,
89 FLAGS_FILL_START
= 2 << TRACE_GRAPH_PRINT_FILL_SHIFT
,
90 FLAGS_FILL_END
= 3 << TRACE_GRAPH_PRINT_FILL_SHIFT
,
94 print_graph_duration(struct trace_array
*tr
, unsigned long long duration
,
95 struct trace_seq
*s
, u32 flags
);
97 int __trace_graph_entry(struct trace_array
*tr
,
98 struct ftrace_graph_ent
*trace
,
99 unsigned int trace_ctx
)
101 struct trace_event_call
*call
= &event_funcgraph_entry
;
102 struct ring_buffer_event
*event
;
103 struct trace_buffer
*buffer
= tr
->array_buffer
.buffer
;
104 struct ftrace_graph_ent_entry
*entry
;
106 event
= trace_buffer_lock_reserve(buffer
, TRACE_GRAPH_ENT
,
107 sizeof(*entry
), trace_ctx
);
110 entry
= ring_buffer_event_data(event
);
111 entry
->graph_ent
= *trace
;
112 if (!call_filter_check_discard(call
, entry
, buffer
, event
))
113 trace_buffer_unlock_commit_nostack(buffer
, event
);
118 static inline int ftrace_graph_ignore_irqs(void)
120 if (!ftrace_graph_skip_irqs
|| trace_recursion_test(TRACE_IRQ_BIT
))
126 int trace_graph_entry(struct ftrace_graph_ent
*trace
)
128 struct trace_array
*tr
= graph_array
;
129 struct trace_array_cpu
*data
;
131 unsigned int trace_ctx
;
136 if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT
))
140 * Do not trace a function if it's filtered by set_graph_notrace.
141 * Make the index of ret stack negative to indicate that it should
142 * ignore further functions. But it needs its own ret stack entry
143 * to recover the original index in order to continue tracing after
144 * returning from the function.
146 if (ftrace_graph_notrace_addr(trace
->func
)) {
147 trace_recursion_set(TRACE_GRAPH_NOTRACE_BIT
);
149 * Need to return 1 to have the return called
150 * that will clear the NOTRACE bit.
155 if (!ftrace_trace_task(tr
))
158 if (ftrace_graph_ignore_func(trace
))
161 if (ftrace_graph_ignore_irqs())
165 * Stop here if tracing_threshold is set. We only write function return
166 * events to the ring buffer.
171 local_irq_save(flags
);
172 cpu
= raw_smp_processor_id();
173 data
= per_cpu_ptr(tr
->array_buffer
.data
, cpu
);
174 disabled
= atomic_inc_return(&data
->disabled
);
175 if (likely(disabled
== 1)) {
176 trace_ctx
= tracing_gen_ctx_flags(flags
);
177 ret
= __trace_graph_entry(tr
, trace
, trace_ctx
);
182 atomic_dec(&data
->disabled
);
183 local_irq_restore(flags
);
189 __trace_graph_function(struct trace_array
*tr
,
190 unsigned long ip
, unsigned int trace_ctx
)
192 u64 time
= trace_clock_local();
193 struct ftrace_graph_ent ent
= {
197 struct ftrace_graph_ret ret
= {
204 __trace_graph_entry(tr
, &ent
, trace_ctx
);
205 __trace_graph_return(tr
, &ret
, trace_ctx
);
209 trace_graph_function(struct trace_array
*tr
,
210 unsigned long ip
, unsigned long parent_ip
,
211 unsigned int trace_ctx
)
213 __trace_graph_function(tr
, ip
, trace_ctx
);
216 void __trace_graph_return(struct trace_array
*tr
,
217 struct ftrace_graph_ret
*trace
,
218 unsigned int trace_ctx
)
220 struct trace_event_call
*call
= &event_funcgraph_exit
;
221 struct ring_buffer_event
*event
;
222 struct trace_buffer
*buffer
= tr
->array_buffer
.buffer
;
223 struct ftrace_graph_ret_entry
*entry
;
225 event
= trace_buffer_lock_reserve(buffer
, TRACE_GRAPH_RET
,
226 sizeof(*entry
), trace_ctx
);
229 entry
= ring_buffer_event_data(event
);
231 if (!call_filter_check_discard(call
, entry
, buffer
, event
))
232 trace_buffer_unlock_commit_nostack(buffer
, event
);
235 void trace_graph_return(struct ftrace_graph_ret
*trace
)
237 struct trace_array
*tr
= graph_array
;
238 struct trace_array_cpu
*data
;
240 unsigned int trace_ctx
;
244 ftrace_graph_addr_finish(trace
);
246 if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT
)) {
247 trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT
);
251 local_irq_save(flags
);
252 cpu
= raw_smp_processor_id();
253 data
= per_cpu_ptr(tr
->array_buffer
.data
, cpu
);
254 disabled
= atomic_inc_return(&data
->disabled
);
255 if (likely(disabled
== 1)) {
256 trace_ctx
= tracing_gen_ctx_flags(flags
);
257 __trace_graph_return(tr
, trace
, trace_ctx
);
259 atomic_dec(&data
->disabled
);
260 local_irq_restore(flags
);
263 void set_graph_array(struct trace_array
*tr
)
267 /* Make graph_array visible before we start tracing */
272 static void trace_graph_thresh_return(struct ftrace_graph_ret
*trace
)
274 ftrace_graph_addr_finish(trace
);
276 if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT
)) {
277 trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT
);
281 if (tracing_thresh
&&
282 (trace
->rettime
- trace
->calltime
< tracing_thresh
))
285 trace_graph_return(trace
);
288 static struct fgraph_ops funcgraph_thresh_ops
= {
289 .entryfunc
= &trace_graph_entry
,
290 .retfunc
= &trace_graph_thresh_return
,
293 static struct fgraph_ops funcgraph_ops
= {
294 .entryfunc
= &trace_graph_entry
,
295 .retfunc
= &trace_graph_return
,
298 static int graph_trace_init(struct trace_array
*tr
)
304 ret
= register_ftrace_graph(&funcgraph_thresh_ops
);
306 ret
= register_ftrace_graph(&funcgraph_ops
);
309 tracing_start_cmdline_record();
314 static void graph_trace_reset(struct trace_array
*tr
)
316 tracing_stop_cmdline_record();
318 unregister_ftrace_graph(&funcgraph_thresh_ops
);
320 unregister_ftrace_graph(&funcgraph_ops
);
323 static int graph_trace_update_thresh(struct trace_array
*tr
)
325 graph_trace_reset(tr
);
326 return graph_trace_init(tr
);
329 static int max_bytes_for_cpu
;
331 static void print_graph_cpu(struct trace_seq
*s
, int cpu
)
334 * Start with a space character - to make it stand out
335 * to the right a bit when trace output is pasted into
338 trace_seq_printf(s
, " %*d) ", max_bytes_for_cpu
, cpu
);
341 #define TRACE_GRAPH_PROCINFO_LENGTH 14
343 static void print_graph_proc(struct trace_seq
*s
, pid_t pid
)
345 char comm
[TASK_COMM_LEN
];
346 /* sign + log10(MAX_INT) + '\0' */
352 trace_find_cmdline(pid
, comm
);
354 sprintf(pid_str
, "%d", pid
);
356 /* 1 stands for the "-" character */
357 len
= strlen(comm
) + strlen(pid_str
) + 1;
359 if (len
< TRACE_GRAPH_PROCINFO_LENGTH
)
360 spaces
= TRACE_GRAPH_PROCINFO_LENGTH
- len
;
362 /* First spaces to align center */
363 for (i
= 0; i
< spaces
/ 2; i
++)
364 trace_seq_putc(s
, ' ');
366 trace_seq_printf(s
, "%s-%s", comm
, pid_str
);
368 /* Last spaces to align center */
369 for (i
= 0; i
< spaces
- (spaces
/ 2); i
++)
370 trace_seq_putc(s
, ' ');
374 static void print_graph_lat_fmt(struct trace_seq
*s
, struct trace_entry
*entry
)
376 trace_seq_putc(s
, ' ');
377 trace_print_lat_fmt(s
, entry
);
378 trace_seq_puts(s
, " | ");
381 /* If the pid changed since the last trace, output this event */
383 verif_pid(struct trace_seq
*s
, pid_t pid
, int cpu
, struct fgraph_data
*data
)
391 last_pid
= &(per_cpu_ptr(data
->cpu_data
, cpu
)->last_pid
);
393 if (*last_pid
== pid
)
396 prev_pid
= *last_pid
;
402 * Context-switch trace line:
404 ------------------------------------------
405 | 1) migration/0--1 => sshd-1755
406 ------------------------------------------
409 trace_seq_puts(s
, " ------------------------------------------\n");
410 print_graph_cpu(s
, cpu
);
411 print_graph_proc(s
, prev_pid
);
412 trace_seq_puts(s
, " => ");
413 print_graph_proc(s
, pid
);
414 trace_seq_puts(s
, "\n ------------------------------------------\n\n");
417 static struct ftrace_graph_ret_entry
*
418 get_return_for_leaf(struct trace_iterator
*iter
,
419 struct ftrace_graph_ent_entry
*curr
)
421 struct fgraph_data
*data
= iter
->private;
422 struct ring_buffer_iter
*ring_iter
= NULL
;
423 struct ring_buffer_event
*event
;
424 struct ftrace_graph_ret_entry
*next
;
427 * If the previous output failed to write to the seq buffer,
428 * then we just reuse the data from before.
430 if (data
&& data
->failed
) {
435 ring_iter
= trace_buffer_iter(iter
, iter
->cpu
);
437 /* First peek to compare current entry and the next one */
439 event
= ring_buffer_iter_peek(ring_iter
, NULL
);
442 * We need to consume the current entry to see
445 ring_buffer_consume(iter
->array_buffer
->buffer
, iter
->cpu
,
447 event
= ring_buffer_peek(iter
->array_buffer
->buffer
, iter
->cpu
,
454 next
= ring_buffer_event_data(event
);
458 * Save current and next entries for later reference
459 * if the output fails.
463 * If the next event is not a return type, then
464 * we only care about what type it is. Otherwise we can
465 * safely copy the entire event.
467 if (next
->ent
.type
== TRACE_GRAPH_RET
)
470 data
->ret
.ent
.type
= next
->ent
.type
;
474 if (next
->ent
.type
!= TRACE_GRAPH_RET
)
477 if (curr
->ent
.pid
!= next
->ent
.pid
||
478 curr
->graph_ent
.func
!= next
->ret
.func
)
481 /* this is a leaf, now advance the iterator */
483 ring_buffer_iter_advance(ring_iter
);
488 static void print_graph_abs_time(u64 t
, struct trace_seq
*s
)
490 unsigned long usecs_rem
;
492 usecs_rem
= do_div(t
, NSEC_PER_SEC
);
495 trace_seq_printf(s
, "%5lu.%06lu | ",
496 (unsigned long)t
, usecs_rem
);
500 print_graph_rel_time(struct trace_iterator
*iter
, struct trace_seq
*s
)
502 unsigned long long usecs
;
504 usecs
= iter
->ts
- iter
->array_buffer
->time_start
;
505 do_div(usecs
, NSEC_PER_USEC
);
507 trace_seq_printf(s
, "%9llu us | ", usecs
);
511 print_graph_irq(struct trace_iterator
*iter
, unsigned long addr
,
512 enum trace_type type
, int cpu
, pid_t pid
, u32 flags
)
514 struct trace_array
*tr
= iter
->tr
;
515 struct trace_seq
*s
= &iter
->seq
;
516 struct trace_entry
*ent
= iter
->ent
;
518 if (addr
< (unsigned long)__irqentry_text_start
||
519 addr
>= (unsigned long)__irqentry_text_end
)
522 if (tr
->trace_flags
& TRACE_ITER_CONTEXT_INFO
) {
524 if (flags
& TRACE_GRAPH_PRINT_ABS_TIME
)
525 print_graph_abs_time(iter
->ts
, s
);
528 if (flags
& TRACE_GRAPH_PRINT_REL_TIME
)
529 print_graph_rel_time(iter
, s
);
532 if (flags
& TRACE_GRAPH_PRINT_CPU
)
533 print_graph_cpu(s
, cpu
);
536 if (flags
& TRACE_GRAPH_PRINT_PROC
) {
537 print_graph_proc(s
, pid
);
538 trace_seq_puts(s
, " | ");
542 if (tr
->trace_flags
& TRACE_ITER_LATENCY_FMT
)
543 print_graph_lat_fmt(s
, ent
);
547 print_graph_duration(tr
, 0, s
, flags
| FLAGS_FILL_START
);
549 if (type
== TRACE_GRAPH_ENT
)
550 trace_seq_puts(s
, "==========>");
552 trace_seq_puts(s
, "<==========");
554 print_graph_duration(tr
, 0, s
, flags
| FLAGS_FILL_END
);
555 trace_seq_putc(s
, '\n');
559 trace_print_graph_duration(unsigned long long duration
, struct trace_seq
*s
)
561 unsigned long nsecs_rem
= do_div(duration
, 1000);
562 /* log10(ULONG_MAX) + '\0' */
568 sprintf(usecs_str
, "%lu", (unsigned long) duration
);
571 trace_seq_printf(s
, "%s", usecs_str
);
573 len
= strlen(usecs_str
);
575 /* Print nsecs (we don't want to exceed 7 numbers) */
577 size_t slen
= min_t(size_t, sizeof(nsecs_str
), 8UL - len
);
579 snprintf(nsecs_str
, slen
, "%03lu", nsecs_rem
);
580 trace_seq_printf(s
, ".%s", nsecs_str
);
581 len
+= strlen(nsecs_str
) + 1;
584 trace_seq_puts(s
, " us ");
586 /* Print remaining spaces to fit the row's width */
587 for (i
= len
; i
< 8; i
++)
588 trace_seq_putc(s
, ' ');
592 print_graph_duration(struct trace_array
*tr
, unsigned long long duration
,
593 struct trace_seq
*s
, u32 flags
)
595 if (!(flags
& TRACE_GRAPH_PRINT_DURATION
) ||
596 !(tr
->trace_flags
& TRACE_ITER_CONTEXT_INFO
))
599 /* No real adata, just filling the column with spaces */
600 switch (flags
& TRACE_GRAPH_PRINT_FILL_MASK
) {
601 case FLAGS_FILL_FULL
:
602 trace_seq_puts(s
, " | ");
604 case FLAGS_FILL_START
:
605 trace_seq_puts(s
, " ");
608 trace_seq_puts(s
, " |");
612 /* Signal a overhead of time execution to the output */
613 if (flags
& TRACE_GRAPH_PRINT_OVERHEAD
)
614 trace_seq_printf(s
, "%c ", trace_find_mark(duration
));
616 trace_seq_puts(s
, " ");
618 trace_print_graph_duration(duration
, s
);
619 trace_seq_puts(s
, "| ");
622 /* Case of a leaf function on its call entry */
623 static enum print_line_t
624 print_graph_entry_leaf(struct trace_iterator
*iter
,
625 struct ftrace_graph_ent_entry
*entry
,
626 struct ftrace_graph_ret_entry
*ret_entry
,
627 struct trace_seq
*s
, u32 flags
)
629 struct fgraph_data
*data
= iter
->private;
630 struct trace_array
*tr
= iter
->tr
;
631 struct ftrace_graph_ret
*graph_ret
;
632 struct ftrace_graph_ent
*call
;
633 unsigned long long duration
;
637 graph_ret
= &ret_entry
->ret
;
638 call
= &entry
->graph_ent
;
639 duration
= graph_ret
->rettime
- graph_ret
->calltime
;
642 struct fgraph_cpu_data
*cpu_data
;
644 cpu_data
= per_cpu_ptr(data
->cpu_data
, cpu
);
647 * Comments display at + 1 to depth. Since
648 * this is a leaf function, keep the comments
649 * equal to this depth.
651 cpu_data
->depth
= call
->depth
- 1;
653 /* No need to keep this function around for this depth */
654 if (call
->depth
< FTRACE_RETFUNC_DEPTH
&&
655 !WARN_ON_ONCE(call
->depth
< 0))
656 cpu_data
->enter_funcs
[call
->depth
] = 0;
659 /* Overhead and duration */
660 print_graph_duration(tr
, duration
, s
, flags
);
663 for (i
= 0; i
< call
->depth
* TRACE_GRAPH_INDENT
; i
++)
664 trace_seq_putc(s
, ' ');
666 trace_seq_printf(s
, "%ps();\n", (void *)call
->func
);
668 print_graph_irq(iter
, graph_ret
->func
, TRACE_GRAPH_RET
,
669 cpu
, iter
->ent
->pid
, flags
);
671 return trace_handle_return(s
);
674 static enum print_line_t
675 print_graph_entry_nested(struct trace_iterator
*iter
,
676 struct ftrace_graph_ent_entry
*entry
,
677 struct trace_seq
*s
, int cpu
, u32 flags
)
679 struct ftrace_graph_ent
*call
= &entry
->graph_ent
;
680 struct fgraph_data
*data
= iter
->private;
681 struct trace_array
*tr
= iter
->tr
;
685 struct fgraph_cpu_data
*cpu_data
;
688 cpu_data
= per_cpu_ptr(data
->cpu_data
, cpu
);
689 cpu_data
->depth
= call
->depth
;
691 /* Save this function pointer to see if the exit matches */
692 if (call
->depth
< FTRACE_RETFUNC_DEPTH
&&
693 !WARN_ON_ONCE(call
->depth
< 0))
694 cpu_data
->enter_funcs
[call
->depth
] = call
->func
;
698 print_graph_duration(tr
, 0, s
, flags
| FLAGS_FILL_FULL
);
701 for (i
= 0; i
< call
->depth
* TRACE_GRAPH_INDENT
; i
++)
702 trace_seq_putc(s
, ' ');
704 trace_seq_printf(s
, "%ps() {\n", (void *)call
->func
);
706 if (trace_seq_has_overflowed(s
))
707 return TRACE_TYPE_PARTIAL_LINE
;
710 * we already consumed the current entry to check the next one
711 * and see if this is a leaf.
713 return TRACE_TYPE_NO_CONSUME
;
717 print_graph_prologue(struct trace_iterator
*iter
, struct trace_seq
*s
,
718 int type
, unsigned long addr
, u32 flags
)
720 struct fgraph_data
*data
= iter
->private;
721 struct trace_entry
*ent
= iter
->ent
;
722 struct trace_array
*tr
= iter
->tr
;
726 verif_pid(s
, ent
->pid
, cpu
, data
);
730 print_graph_irq(iter
, addr
, type
, cpu
, ent
->pid
, flags
);
732 if (!(tr
->trace_flags
& TRACE_ITER_CONTEXT_INFO
))
736 if (flags
& TRACE_GRAPH_PRINT_ABS_TIME
)
737 print_graph_abs_time(iter
->ts
, s
);
740 if (flags
& TRACE_GRAPH_PRINT_REL_TIME
)
741 print_graph_rel_time(iter
, s
);
744 if (flags
& TRACE_GRAPH_PRINT_CPU
)
745 print_graph_cpu(s
, cpu
);
748 if (flags
& TRACE_GRAPH_PRINT_PROC
) {
749 print_graph_proc(s
, ent
->pid
);
750 trace_seq_puts(s
, " | ");
754 if (tr
->trace_flags
& TRACE_ITER_LATENCY_FMT
)
755 print_graph_lat_fmt(s
, ent
);
761 * Entry check for irq code
764 * - we are inside irq code
765 * - we just entered irq code
768 * - funcgraph-interrupts option is set
769 * - we are not inside irq code
772 check_irq_entry(struct trace_iterator
*iter
, u32 flags
,
773 unsigned long addr
, int depth
)
777 struct fgraph_data
*data
= iter
->private;
780 * If we are either displaying irqs, or we got called as
781 * a graph event and private data does not exist,
782 * then we bypass the irq check.
784 if ((flags
& TRACE_GRAPH_PRINT_IRQS
) ||
788 depth_irq
= &(per_cpu_ptr(data
->cpu_data
, cpu
)->depth_irq
);
791 * We are inside the irq code
796 if ((addr
< (unsigned long)__irqentry_text_start
) ||
797 (addr
>= (unsigned long)__irqentry_text_end
))
801 * We are entering irq code.
808 * Return check for irq code
811 * - we are inside irq code
812 * - we just left irq code
815 * - funcgraph-interrupts option is set
816 * - we are not inside irq code
819 check_irq_return(struct trace_iterator
*iter
, u32 flags
, int depth
)
823 struct fgraph_data
*data
= iter
->private;
826 * If we are either displaying irqs, or we got called as
827 * a graph event and private data does not exist,
828 * then we bypass the irq check.
830 if ((flags
& TRACE_GRAPH_PRINT_IRQS
) ||
834 depth_irq
= &(per_cpu_ptr(data
->cpu_data
, cpu
)->depth_irq
);
837 * We are not inside the irq code.
839 if (*depth_irq
== -1)
843 * We are inside the irq code, and this is returning entry.
844 * Let's not trace it and clear the entry depth, since
845 * we are out of irq code.
847 * This condition ensures that we 'leave the irq code' once
848 * we are out of the entry depth. Thus protecting us from
849 * the RETURN entry loss.
851 if (*depth_irq
>= depth
) {
857 * We are inside the irq code, and this is not the entry.
862 static enum print_line_t
863 print_graph_entry(struct ftrace_graph_ent_entry
*field
, struct trace_seq
*s
,
864 struct trace_iterator
*iter
, u32 flags
)
866 struct fgraph_data
*data
= iter
->private;
867 struct ftrace_graph_ent
*call
= &field
->graph_ent
;
868 struct ftrace_graph_ret_entry
*leaf_ret
;
869 static enum print_line_t ret
;
872 if (check_irq_entry(iter
, flags
, call
->func
, call
->depth
))
873 return TRACE_TYPE_HANDLED
;
875 print_graph_prologue(iter
, s
, TRACE_GRAPH_ENT
, call
->func
, flags
);
877 leaf_ret
= get_return_for_leaf(iter
, field
);
879 ret
= print_graph_entry_leaf(iter
, field
, leaf_ret
, s
, flags
);
881 ret
= print_graph_entry_nested(iter
, field
, s
, cpu
, flags
);
885 * If we failed to write our output, then we need to make
886 * note of it. Because we already consumed our entry.
898 static enum print_line_t
899 print_graph_return(struct ftrace_graph_ret
*trace
, struct trace_seq
*s
,
900 struct trace_entry
*ent
, struct trace_iterator
*iter
,
903 unsigned long long duration
= trace
->rettime
- trace
->calltime
;
904 struct fgraph_data
*data
= iter
->private;
905 struct trace_array
*tr
= iter
->tr
;
906 pid_t pid
= ent
->pid
;
911 if (check_irq_return(iter
, flags
, trace
->depth
))
912 return TRACE_TYPE_HANDLED
;
915 struct fgraph_cpu_data
*cpu_data
;
918 cpu_data
= per_cpu_ptr(data
->cpu_data
, cpu
);
921 * Comments display at + 1 to depth. This is the
922 * return from a function, we now want the comments
923 * to display at the same level of the bracket.
925 cpu_data
->depth
= trace
->depth
- 1;
927 if (trace
->depth
< FTRACE_RETFUNC_DEPTH
&&
928 !WARN_ON_ONCE(trace
->depth
< 0)) {
929 if (cpu_data
->enter_funcs
[trace
->depth
] != trace
->func
)
931 cpu_data
->enter_funcs
[trace
->depth
] = 0;
935 print_graph_prologue(iter
, s
, 0, 0, flags
);
937 /* Overhead and duration */
938 print_graph_duration(tr
, duration
, s
, flags
);
941 for (i
= 0; i
< trace
->depth
* TRACE_GRAPH_INDENT
; i
++)
942 trace_seq_putc(s
, ' ');
945 * If the return function does not have a matching entry,
946 * then the entry was lost. Instead of just printing
947 * the '}' and letting the user guess what function this
948 * belongs to, write out the function name. Always do
949 * that if the funcgraph-tail option is enabled.
951 if (func_match
&& !(flags
& TRACE_GRAPH_PRINT_TAIL
))
952 trace_seq_puts(s
, "}\n");
954 trace_seq_printf(s
, "} /* %ps */\n", (void *)trace
->func
);
957 if (flags
& TRACE_GRAPH_PRINT_OVERRUN
)
958 trace_seq_printf(s
, " (Overruns: %u)\n",
961 print_graph_irq(iter
, trace
->func
, TRACE_GRAPH_RET
,
964 return trace_handle_return(s
);
967 static enum print_line_t
968 print_graph_comment(struct trace_seq
*s
, struct trace_entry
*ent
,
969 struct trace_iterator
*iter
, u32 flags
)
971 struct trace_array
*tr
= iter
->tr
;
972 unsigned long sym_flags
= (tr
->trace_flags
& TRACE_ITER_SYM_MASK
);
973 struct fgraph_data
*data
= iter
->private;
974 struct trace_event
*event
;
980 depth
= per_cpu_ptr(data
->cpu_data
, iter
->cpu
)->depth
;
982 print_graph_prologue(iter
, s
, 0, 0, flags
);
985 print_graph_duration(tr
, 0, s
, flags
| FLAGS_FILL_FULL
);
989 for (i
= 0; i
< (depth
+ 1) * TRACE_GRAPH_INDENT
; i
++)
990 trace_seq_putc(s
, ' ');
993 trace_seq_puts(s
, "/* ");
995 switch (iter
->ent
->type
) {
997 ret
= trace_print_bputs_msg_only(iter
);
998 if (ret
!= TRACE_TYPE_HANDLED
)
1002 ret
= trace_print_bprintk_msg_only(iter
);
1003 if (ret
!= TRACE_TYPE_HANDLED
)
1007 ret
= trace_print_printk_msg_only(iter
);
1008 if (ret
!= TRACE_TYPE_HANDLED
)
1012 event
= ftrace_find_event(ent
->type
);
1014 return TRACE_TYPE_UNHANDLED
;
1016 ret
= event
->funcs
->trace(iter
, sym_flags
, event
);
1017 if (ret
!= TRACE_TYPE_HANDLED
)
1021 if (trace_seq_has_overflowed(s
))
1024 /* Strip ending newline */
1025 if (s
->buffer
[s
->seq
.len
- 1] == '\n') {
1026 s
->buffer
[s
->seq
.len
- 1] = '\0';
1030 trace_seq_puts(s
, " */\n");
1032 return trace_handle_return(s
);
1037 print_graph_function_flags(struct trace_iterator
*iter
, u32 flags
)
1039 struct ftrace_graph_ent_entry
*field
;
1040 struct fgraph_data
*data
= iter
->private;
1041 struct trace_entry
*entry
= iter
->ent
;
1042 struct trace_seq
*s
= &iter
->seq
;
1043 int cpu
= iter
->cpu
;
1046 if (data
&& per_cpu_ptr(data
->cpu_data
, cpu
)->ignore
) {
1047 per_cpu_ptr(data
->cpu_data
, cpu
)->ignore
= 0;
1048 return TRACE_TYPE_HANDLED
;
1052 * If the last output failed, there's a possibility we need
1053 * to print out the missing entry which would never go out.
1055 if (data
&& data
->failed
) {
1057 iter
->cpu
= data
->cpu
;
1058 ret
= print_graph_entry(field
, s
, iter
, flags
);
1059 if (ret
== TRACE_TYPE_HANDLED
&& iter
->cpu
!= cpu
) {
1060 per_cpu_ptr(data
->cpu_data
, iter
->cpu
)->ignore
= 1;
1061 ret
= TRACE_TYPE_NO_CONSUME
;
1067 switch (entry
->type
) {
1068 case TRACE_GRAPH_ENT
: {
1070 * print_graph_entry() may consume the current event,
1071 * thus @field may become invalid, so we need to save it.
1072 * sizeof(struct ftrace_graph_ent_entry) is very small,
1073 * it can be safely saved at the stack.
1075 struct ftrace_graph_ent_entry saved
;
1076 trace_assign_type(field
, entry
);
1078 return print_graph_entry(&saved
, s
, iter
, flags
);
1080 case TRACE_GRAPH_RET
: {
1081 struct ftrace_graph_ret_entry
*field
;
1082 trace_assign_type(field
, entry
);
1083 return print_graph_return(&field
->ret
, s
, entry
, iter
, flags
);
1087 /* dont trace stack and functions as comments */
1088 return TRACE_TYPE_UNHANDLED
;
1091 return print_graph_comment(s
, entry
, iter
, flags
);
1094 return TRACE_TYPE_HANDLED
;
1097 static enum print_line_t
1098 print_graph_function(struct trace_iterator
*iter
)
1100 return print_graph_function_flags(iter
, tracer_flags
.val
);
1103 static enum print_line_t
1104 print_graph_function_event(struct trace_iterator
*iter
, int flags
,
1105 struct trace_event
*event
)
1107 return print_graph_function(iter
);
1110 static void print_lat_header(struct seq_file
*s
, u32 flags
)
1112 static const char spaces
[] = " " /* 16 spaces */
1114 " "; /* 17 spaces */
1117 if (flags
& TRACE_GRAPH_PRINT_ABS_TIME
)
1119 if (flags
& TRACE_GRAPH_PRINT_REL_TIME
)
1121 if (flags
& TRACE_GRAPH_PRINT_CPU
)
1123 if (flags
& TRACE_GRAPH_PRINT_PROC
)
1126 seq_printf(s
, "#%.*s _-----=> irqs-off \n", size
, spaces
);
1127 seq_printf(s
, "#%.*s / _----=> need-resched \n", size
, spaces
);
1128 seq_printf(s
, "#%.*s| / _---=> hardirq/softirq \n", size
, spaces
);
1129 seq_printf(s
, "#%.*s|| / _--=> preempt-depth \n", size
, spaces
);
1130 seq_printf(s
, "#%.*s||| / \n", size
, spaces
);
1133 static void __print_graph_headers_flags(struct trace_array
*tr
,
1134 struct seq_file
*s
, u32 flags
)
1136 int lat
= tr
->trace_flags
& TRACE_ITER_LATENCY_FMT
;
1139 print_lat_header(s
, flags
);
1143 if (flags
& TRACE_GRAPH_PRINT_ABS_TIME
)
1144 seq_puts(s
, " TIME ");
1145 if (flags
& TRACE_GRAPH_PRINT_REL_TIME
)
1146 seq_puts(s
, " REL TIME ");
1147 if (flags
& TRACE_GRAPH_PRINT_CPU
)
1148 seq_puts(s
, " CPU");
1149 if (flags
& TRACE_GRAPH_PRINT_PROC
)
1150 seq_puts(s
, " TASK/PID ");
1152 seq_puts(s
, "|||| ");
1153 if (flags
& TRACE_GRAPH_PRINT_DURATION
)
1154 seq_puts(s
, " DURATION ");
1155 seq_puts(s
, " FUNCTION CALLS\n");
1159 if (flags
& TRACE_GRAPH_PRINT_ABS_TIME
)
1161 if (flags
& TRACE_GRAPH_PRINT_REL_TIME
)
1163 if (flags
& TRACE_GRAPH_PRINT_CPU
)
1165 if (flags
& TRACE_GRAPH_PRINT_PROC
)
1166 seq_puts(s
, " | | ");
1168 seq_puts(s
, "|||| ");
1169 if (flags
& TRACE_GRAPH_PRINT_DURATION
)
1170 seq_puts(s
, " | | ");
1171 seq_puts(s
, " | | | |\n");
1174 static void print_graph_headers(struct seq_file
*s
)
1176 print_graph_headers_flags(s
, tracer_flags
.val
);
1179 void print_graph_headers_flags(struct seq_file
*s
, u32 flags
)
1181 struct trace_iterator
*iter
= s
->private;
1182 struct trace_array
*tr
= iter
->tr
;
1184 if (!(tr
->trace_flags
& TRACE_ITER_CONTEXT_INFO
))
1187 if (tr
->trace_flags
& TRACE_ITER_LATENCY_FMT
) {
1188 /* print nothing if the buffers are empty */
1189 if (trace_empty(iter
))
1192 print_trace_header(s
, iter
);
1195 __print_graph_headers_flags(tr
, s
, flags
);
1198 void graph_trace_open(struct trace_iterator
*iter
)
1200 /* pid and depth on the last trace processed */
1201 struct fgraph_data
*data
;
1205 iter
->private = NULL
;
1207 /* We can be called in atomic context via ftrace_dump() */
1208 gfpflags
= (in_atomic() || irqs_disabled()) ? GFP_ATOMIC
: GFP_KERNEL
;
1210 data
= kzalloc(sizeof(*data
), gfpflags
);
1214 data
->cpu_data
= alloc_percpu_gfp(struct fgraph_cpu_data
, gfpflags
);
1215 if (!data
->cpu_data
)
1218 for_each_possible_cpu(cpu
) {
1219 pid_t
*pid
= &(per_cpu_ptr(data
->cpu_data
, cpu
)->last_pid
);
1220 int *depth
= &(per_cpu_ptr(data
->cpu_data
, cpu
)->depth
);
1221 int *ignore
= &(per_cpu_ptr(data
->cpu_data
, cpu
)->ignore
);
1222 int *depth_irq
= &(per_cpu_ptr(data
->cpu_data
, cpu
)->depth_irq
);
1230 iter
->private = data
;
1237 pr_warn("function graph tracer: not enough memory\n");
1240 void graph_trace_close(struct trace_iterator
*iter
)
1242 struct fgraph_data
*data
= iter
->private;
1245 free_percpu(data
->cpu_data
);
1251 func_graph_set_flag(struct trace_array
*tr
, u32 old_flags
, u32 bit
, int set
)
1253 if (bit
== TRACE_GRAPH_PRINT_IRQS
)
1254 ftrace_graph_skip_irqs
= !set
;
1256 if (bit
== TRACE_GRAPH_SLEEP_TIME
)
1257 ftrace_graph_sleep_time_control(set
);
1259 if (bit
== TRACE_GRAPH_GRAPH_TIME
)
1260 ftrace_graph_graph_time_control(set
);
1265 static struct trace_event_functions graph_functions
= {
1266 .trace
= print_graph_function_event
,
1269 static struct trace_event graph_trace_entry_event
= {
1270 .type
= TRACE_GRAPH_ENT
,
1271 .funcs
= &graph_functions
,
1274 static struct trace_event graph_trace_ret_event
= {
1275 .type
= TRACE_GRAPH_RET
,
1276 .funcs
= &graph_functions
1279 static struct tracer graph_trace __tracer_data
= {
1280 .name
= "function_graph",
1281 .update_thresh
= graph_trace_update_thresh
,
1282 .open
= graph_trace_open
,
1283 .pipe_open
= graph_trace_open
,
1284 .close
= graph_trace_close
,
1285 .pipe_close
= graph_trace_close
,
1286 .init
= graph_trace_init
,
1287 .reset
= graph_trace_reset
,
1288 .print_line
= print_graph_function
,
1289 .print_header
= print_graph_headers
,
1290 .flags
= &tracer_flags
,
1291 .set_flag
= func_graph_set_flag
,
1292 #ifdef CONFIG_FTRACE_SELFTEST
1293 .selftest
= trace_selftest_startup_function_graph
,
1299 graph_depth_write(struct file
*filp
, const char __user
*ubuf
, size_t cnt
,
1305 ret
= kstrtoul_from_user(ubuf
, cnt
, 10, &val
);
1309 fgraph_max_depth
= val
;
1317 graph_depth_read(struct file
*filp
, char __user
*ubuf
, size_t cnt
,
1320 char buf
[15]; /* More than enough to hold UINT_MAX + "\n"*/
1323 n
= sprintf(buf
, "%d\n", fgraph_max_depth
);
1325 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, n
);
1328 static const struct file_operations graph_depth_fops
= {
1329 .open
= tracing_open_generic
,
1330 .write
= graph_depth_write
,
1331 .read
= graph_depth_read
,
1332 .llseek
= generic_file_llseek
,
1335 static __init
int init_graph_tracefs(void)
1339 ret
= tracing_init_dentry();
1343 trace_create_file("max_graph_depth", 0644, NULL
,
1344 NULL
, &graph_depth_fops
);
1348 fs_initcall(init_graph_tracefs
);
1350 static __init
int init_graph_trace(void)
1352 max_bytes_for_cpu
= snprintf(NULL
, 0, "%u", nr_cpu_ids
- 1);
1354 if (!register_trace_event(&graph_trace_entry_event
)) {
1355 pr_warn("Warning: could not register graph trace events\n");
1359 if (!register_trace_event(&graph_trace_ret_event
)) {
1360 pr_warn("Warning: could not register graph trace events\n");
1364 return register_tracer(&graph_trace
);
1367 core_initcall(init_graph_trace
);