2 * ring buffer based function tracer
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 * Originally taken from the RT patch by:
8 * Arnaldo Carvalho de Melo <acme@redhat.com>
10 * Based on code from the latency_tracer, that is:
11 * Copyright (C) 2004-2006 Ingo Molnar
12 * Copyright (C) 2004 William Lee Irwin III
14 #include <linux/utsrelease.h>
15 #include <linux/kallsyms.h>
16 #include <linux/seq_file.h>
17 #include <linux/debugfs.h>
18 #include <linux/pagemap.h>
19 #include <linux/hardirq.h>
20 #include <linux/linkage.h>
21 #include <linux/uaccess.h>
22 #include <linux/ftrace.h>
23 #include <linux/module.h>
24 #include <linux/percpu.h>
25 #include <linux/ctype.h>
26 #include <linux/init.h>
27 #include <linux/gfp.h>
32 unsigned long __read_mostly tracing_max_latency
= (cycle_t
)ULONG_MAX
;
33 unsigned long __read_mostly tracing_thresh
;
35 static int tracing_disabled
= 1;
38 ns2usecs(cycle_t nsec
)
45 static atomic_t tracer_counter
;
46 static struct trace_array global_trace
;
48 static DEFINE_PER_CPU(struct trace_array_cpu
, global_trace_cpu
);
50 static struct trace_array max_tr
;
52 static DEFINE_PER_CPU(struct trace_array_cpu
, max_data
);
54 static int tracer_enabled
;
55 static unsigned long trace_nr_entries
= 16384UL;
57 static struct tracer
*trace_types __read_mostly
;
58 static struct tracer
*current_trace __read_mostly
;
59 static int max_tracer_type_len
;
61 static DEFINE_MUTEX(trace_types_lock
);
63 #define ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(struct trace_entry))
65 static int __init
set_nr_entries(char *str
)
69 trace_nr_entries
= simple_strtoul(str
, &str
, 0);
72 __setup("trace_entries=", set_nr_entries
);
74 unsigned long nsecs_to_usecs(unsigned long nsecs
)
80 __TRACE_FIRST_TYPE
= 0,
88 enum trace_flag_type
{
89 TRACE_FLAG_IRQS_OFF
= 0x01,
90 TRACE_FLAG_NEED_RESCHED
= 0x02,
91 TRACE_FLAG_HARDIRQ
= 0x04,
92 TRACE_FLAG_SOFTIRQ
= 0x08,
95 enum trace_iterator_flags
{
96 TRACE_ITER_PRINT_PARENT
= 0x01,
97 TRACE_ITER_SYM_OFFSET
= 0x02,
98 TRACE_ITER_SYM_ADDR
= 0x04,
99 TRACE_ITER_VERBOSE
= 0x08,
102 #define TRACE_ITER_SYM_MASK \
103 (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
105 /* These must match the bit postions above */
106 static const char *trace_options
[] = {
114 static unsigned trace_flags
;
116 static DEFINE_SPINLOCK(ftrace_max_lock
);
119 * Copy the new maximum trace into the separate maximum-trace
120 * structure. (this way the maximum trace is permanently saved,
121 * for later retrieval via /debugfs/tracing/latency_trace)
124 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
126 struct trace_array_cpu
*data
= tr
->data
[cpu
];
129 max_tr
.time_start
= data
->preempt_timestamp
;
131 data
= max_tr
.data
[cpu
];
132 data
->saved_latency
= tracing_max_latency
;
134 memcpy(data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
135 data
->pid
= tsk
->pid
;
136 data
->uid
= tsk
->uid
;
137 data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
138 data
->policy
= tsk
->policy
;
139 data
->rt_priority
= tsk
->rt_priority
;
141 /* record this tasks comm */
142 tracing_record_cmdline(current
);
145 void check_pages(struct trace_array_cpu
*data
)
147 struct page
*page
, *tmp
;
149 BUG_ON(data
->trace_pages
.next
->prev
!= &data
->trace_pages
);
150 BUG_ON(data
->trace_pages
.prev
->next
!= &data
->trace_pages
);
152 list_for_each_entry_safe(page
, tmp
, &data
->trace_pages
, lru
) {
153 BUG_ON(page
->lru
.next
->prev
!= &page
->lru
);
154 BUG_ON(page
->lru
.prev
->next
!= &page
->lru
);
158 void *head_page(struct trace_array_cpu
*data
)
163 if (list_empty(&data
->trace_pages
))
166 page
= list_entry(data
->trace_pages
.next
, struct page
, lru
);
167 BUG_ON(&page
->lru
== &data
->trace_pages
);
169 return page_address(page
);
173 trace_seq_printf(struct trace_seq
*s
, const char *fmt
, ...)
175 int len
= (PAGE_SIZE
- 1) - s
->len
;
183 ret
= vsnprintf(s
->buffer
+ s
->len
, len
, fmt
, ap
);
186 /* If we can't write it all, don't bother writing anything */
196 trace_seq_puts(struct trace_seq
*s
, const char *str
)
198 int len
= strlen(str
);
200 if (len
> ((PAGE_SIZE
- 1) - s
->len
))
203 memcpy(s
->buffer
+ s
->len
, str
, len
);
210 trace_seq_putc(struct trace_seq
*s
, unsigned char c
)
212 if (s
->len
>= (PAGE_SIZE
- 1))
215 s
->buffer
[s
->len
++] = c
;
221 trace_seq_reset(struct trace_seq
*s
)
227 trace_print_seq(struct seq_file
*m
, struct trace_seq
*s
)
229 int len
= s
->len
>= PAGE_SIZE
? PAGE_SIZE
- 1 : s
->len
;
232 seq_puts(m
, s
->buffer
);
238 flip_trace(struct trace_array_cpu
*tr1
, struct trace_array_cpu
*tr2
)
240 struct list_head flip_pages
;
242 INIT_LIST_HEAD(&flip_pages
);
244 memcpy(&tr1
->trace_head_idx
, &tr2
->trace_head_idx
,
245 sizeof(struct trace_array_cpu
) -
246 offsetof(struct trace_array_cpu
, trace_head_idx
));
250 list_splice_init(&tr1
->trace_pages
, &flip_pages
);
251 list_splice_init(&tr2
->trace_pages
, &tr1
->trace_pages
);
252 list_splice_init(&flip_pages
, &tr2
->trace_pages
);
253 BUG_ON(!list_empty(&flip_pages
));
259 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
261 struct trace_array_cpu
*data
;
264 WARN_ON_ONCE(!irqs_disabled());
265 spin_lock(&ftrace_max_lock
);
266 /* clear out all the previous traces */
267 for_each_possible_cpu(i
) {
269 flip_trace(max_tr
.data
[i
], data
);
273 __update_max_tr(tr
, tsk
, cpu
);
274 spin_unlock(&ftrace_max_lock
);
278 * update_max_tr_single - only copy one trace over, and reset the rest
280 * @tsk - task with the latency
281 * @cpu - the cpu of the buffer to copy.
284 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
286 struct trace_array_cpu
*data
= tr
->data
[cpu
];
289 WARN_ON_ONCE(!irqs_disabled());
290 spin_lock(&ftrace_max_lock
);
291 for_each_possible_cpu(i
)
292 tracing_reset(max_tr
.data
[i
]);
294 flip_trace(max_tr
.data
[cpu
], data
);
297 __update_max_tr(tr
, tsk
, cpu
);
298 spin_unlock(&ftrace_max_lock
);
301 int register_tracer(struct tracer
*type
)
308 pr_info("Tracer must have a name\n");
312 mutex_lock(&trace_types_lock
);
313 for (t
= trace_types
; t
; t
= t
->next
) {
314 if (strcmp(type
->name
, t
->name
) == 0) {
316 pr_info("Trace %s already registered\n",
323 #ifdef CONFIG_FTRACE_STARTUP_TEST
324 if (type
->selftest
) {
325 struct tracer
*saved_tracer
= current_trace
;
326 struct trace_array_cpu
*data
;
327 struct trace_array
*tr
= &global_trace
;
328 int saved_ctrl
= tr
->ctrl
;
331 * Run a selftest on this tracer.
332 * Here we reset the trace buffer, and set the current
333 * tracer to be this tracer. The tracer can then run some
334 * internal tracing to verify that everything is in order.
335 * If we fail, we do not register this tracer.
337 for_each_possible_cpu(i
) {
339 if (!head_page(data
))
343 current_trace
= type
;
345 /* the test is responsible for initializing and enabling */
346 pr_info("Testing tracer %s: ", type
->name
);
347 ret
= type
->selftest(type
, tr
);
348 /* the test is responsible for resetting too */
349 current_trace
= saved_tracer
;
350 tr
->ctrl
= saved_ctrl
;
352 printk(KERN_CONT
"FAILED!\n");
355 /* Only reset on passing, to avoid touching corrupted buffers */
356 for_each_possible_cpu(i
) {
358 if (!head_page(data
))
362 printk(KERN_CONT
"PASSED\n");
366 type
->next
= trace_types
;
368 len
= strlen(type
->name
);
369 if (len
> max_tracer_type_len
)
370 max_tracer_type_len
= len
;
373 mutex_unlock(&trace_types_lock
);
378 void unregister_tracer(struct tracer
*type
)
383 mutex_lock(&trace_types_lock
);
384 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
388 pr_info("Trace %s not registered\n", type
->name
);
393 if (strlen(type
->name
) != max_tracer_type_len
)
396 max_tracer_type_len
= 0;
397 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
398 len
= strlen((*t
)->name
);
399 if (len
> max_tracer_type_len
)
400 max_tracer_type_len
= len
;
403 mutex_unlock(&trace_types_lock
);
406 notrace
void tracing_reset(struct trace_array_cpu
*data
)
409 data
->trace_head
= data
->trace_tail
= head_page(data
);
410 data
->trace_head_idx
= 0;
411 data
->trace_tail_idx
= 0;
416 function_trace_call(unsigned long ip
, unsigned long parent_ip
)
418 struct trace_array
*tr
= &global_trace
;
419 struct trace_array_cpu
*data
;
424 if (unlikely(!tracer_enabled
))
427 local_irq_save(flags
);
428 cpu
= raw_smp_processor_id();
429 data
= tr
->data
[cpu
];
430 disabled
= atomic_inc_return(&data
->disabled
);
432 if (likely(disabled
== 1))
433 ftrace(tr
, data
, ip
, parent_ip
, flags
);
435 atomic_dec(&data
->disabled
);
436 local_irq_restore(flags
);
439 static struct ftrace_ops trace_ops __read_mostly
=
441 .func
= function_trace_call
,
445 notrace
void tracing_start_function_trace(void)
447 register_ftrace_function(&trace_ops
);
450 notrace
void tracing_stop_function_trace(void)
452 unregister_ftrace_function(&trace_ops
);
455 #define SAVED_CMDLINES 128
456 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
457 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
458 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
459 static int cmdline_idx
;
460 static DEFINE_SPINLOCK(trace_cmdline_lock
);
461 atomic_t trace_record_cmdline_disabled
;
463 static void trace_init_cmdlines(void)
465 memset(&map_pid_to_cmdline
, -1, sizeof(map_pid_to_cmdline
));
466 memset(&map_cmdline_to_pid
, -1, sizeof(map_cmdline_to_pid
));
470 notrace
void trace_stop_cmdline_recording(void);
472 static notrace
void trace_save_cmdline(struct task_struct
*tsk
)
477 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
481 * It's not the end of the world if we don't get
482 * the lock, but we also don't want to spin
483 * nor do we want to disable interrupts,
484 * so if we miss here, then better luck next time.
486 if (!spin_trylock(&trace_cmdline_lock
))
489 idx
= map_pid_to_cmdline
[tsk
->pid
];
490 if (idx
>= SAVED_CMDLINES
) {
491 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
493 map
= map_cmdline_to_pid
[idx
];
494 if (map
<= PID_MAX_DEFAULT
)
495 map_pid_to_cmdline
[map
] = (unsigned)-1;
497 map_pid_to_cmdline
[tsk
->pid
] = idx
;
502 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
504 spin_unlock(&trace_cmdline_lock
);
507 static notrace
char *trace_find_cmdline(int pid
)
509 char *cmdline
= "<...>";
515 if (pid
> PID_MAX_DEFAULT
)
518 map
= map_pid_to_cmdline
[pid
];
519 if (map
>= SAVED_CMDLINES
)
522 cmdline
= saved_cmdlines
[map
];
528 notrace
void tracing_record_cmdline(struct task_struct
*tsk
)
530 if (atomic_read(&trace_record_cmdline_disabled
))
533 trace_save_cmdline(tsk
);
536 static inline notrace
struct list_head
*
537 trace_next_list(struct trace_array_cpu
*data
, struct list_head
*next
)
540 * Roundrobin - but skip the head (which is not a real page):
543 if (unlikely(next
== &data
->trace_pages
))
545 BUG_ON(next
== &data
->trace_pages
);
550 static inline notrace
void *
551 trace_next_page(struct trace_array_cpu
*data
, void *addr
)
553 struct list_head
*next
;
556 page
= virt_to_page(addr
);
558 next
= trace_next_list(data
, &page
->lru
);
559 page
= list_entry(next
, struct page
, lru
);
561 return page_address(page
);
564 static inline notrace
struct trace_entry
*
565 tracing_get_trace_entry(struct trace_array
*tr
, struct trace_array_cpu
*data
)
567 unsigned long idx
, idx_next
;
568 struct trace_entry
*entry
;
571 idx
= data
->trace_head_idx
;
574 BUG_ON(idx
* TRACE_ENTRY_SIZE
>= PAGE_SIZE
);
576 entry
= data
->trace_head
+ idx
* TRACE_ENTRY_SIZE
;
578 if (unlikely(idx_next
>= ENTRIES_PER_PAGE
)) {
579 data
->trace_head
= trace_next_page(data
, data
->trace_head
);
583 if (data
->trace_head
== data
->trace_tail
&&
584 idx_next
== data
->trace_tail_idx
) {
586 data
->trace_tail_idx
++;
587 if (data
->trace_tail_idx
>= ENTRIES_PER_PAGE
) {
589 trace_next_page(data
, data
->trace_tail
);
590 data
->trace_tail_idx
= 0;
594 data
->trace_head_idx
= idx_next
;
599 static inline notrace
void
600 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
)
602 struct task_struct
*tsk
= current
;
605 pc
= preempt_count();
607 entry
->idx
= atomic_inc_return(&tracer_counter
);
608 entry
->preempt_count
= pc
& 0xff;
609 entry
->pid
= tsk
->pid
;
610 entry
->t
= now(raw_smp_processor_id());
611 entry
->flags
= (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
612 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
613 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
614 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
618 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
619 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
)
621 struct trace_entry
*entry
;
623 spin_lock(&data
->lock
);
624 entry
= tracing_get_trace_entry(tr
, data
);
625 tracing_generic_entry_update(entry
, flags
);
626 entry
->type
= TRACE_FN
;
628 entry
->fn
.parent_ip
= parent_ip
;
629 spin_unlock(&data
->lock
);
633 tracing_sched_switch_trace(struct trace_array
*tr
,
634 struct trace_array_cpu
*data
,
635 struct task_struct
*prev
, struct task_struct
*next
,
638 struct trace_entry
*entry
;
640 spin_lock(&data
->lock
);
641 entry
= tracing_get_trace_entry(tr
, data
);
642 tracing_generic_entry_update(entry
, flags
);
643 entry
->type
= TRACE_CTX
;
644 entry
->ctx
.prev_pid
= prev
->pid
;
645 entry
->ctx
.prev_prio
= prev
->prio
;
646 entry
->ctx
.prev_state
= prev
->state
;
647 entry
->ctx
.next_pid
= next
->pid
;
648 entry
->ctx
.next_prio
= next
->prio
;
649 spin_unlock(&data
->lock
);
652 enum trace_file_type
{
653 TRACE_FILE_LAT_FMT
= 1,
656 static struct trace_entry
*
657 trace_entry_idx(struct trace_array
*tr
, struct trace_array_cpu
*data
,
658 struct trace_iterator
*iter
, int cpu
)
661 struct trace_entry
*array
;
663 if (iter
->next_idx
[cpu
] >= tr
->entries
||
664 iter
->next_idx
[cpu
] >= data
->trace_idx
||
665 (data
->trace_head
== data
->trace_tail
&&
666 data
->trace_head_idx
== data
->trace_tail_idx
))
669 if (!iter
->next_page
[cpu
]) {
670 /* Initialize the iterator for this cpu trace buffer */
671 WARN_ON(!data
->trace_tail
);
672 page
= virt_to_page(data
->trace_tail
);
673 iter
->next_page
[cpu
] = &page
->lru
;
674 iter
->next_page_idx
[cpu
] = data
->trace_tail_idx
;
677 page
= list_entry(iter
->next_page
[cpu
], struct page
, lru
);
678 BUG_ON(&data
->trace_pages
== &page
->lru
);
680 array
= page_address(page
);
682 /* Still possible to catch up to the tail */
683 if (iter
->next_idx
[cpu
] && array
== data
->trace_tail
&&
684 iter
->next_page_idx
[cpu
] == data
->trace_tail_idx
)
687 WARN_ON(iter
->next_page_idx
[cpu
] >= ENTRIES_PER_PAGE
);
688 return &array
[iter
->next_page_idx
[cpu
]];
691 static struct notrace trace_entry
*
692 find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
)
694 struct trace_array
*tr
= iter
->tr
;
695 struct trace_entry
*ent
, *next
= NULL
;
699 for_each_possible_cpu(cpu
) {
700 if (!head_page(tr
->data
[cpu
]))
702 ent
= trace_entry_idx(tr
, tr
->data
[cpu
], iter
, cpu
);
704 (!next
|| (long)(next
->idx
- ent
->idx
) > 0)) {
717 trace_iterator_increment(struct trace_iterator
*iter
)
720 iter
->next_idx
[iter
->cpu
]++;
721 iter
->next_page_idx
[iter
->cpu
]++;
722 if (iter
->next_page_idx
[iter
->cpu
] >= ENTRIES_PER_PAGE
) {
723 struct trace_array_cpu
*data
= iter
->tr
->data
[iter
->cpu
];
725 iter
->next_page_idx
[iter
->cpu
] = 0;
726 iter
->next_page
[iter
->cpu
] =
727 trace_next_list(data
, iter
->next_page
[iter
->cpu
]);
732 trace_consume(struct trace_iterator
*iter
)
734 struct trace_array_cpu
*data
= iter
->tr
->data
[iter
->cpu
];
736 data
->trace_tail_idx
++;
737 if (data
->trace_tail_idx
>= ENTRIES_PER_PAGE
) {
738 data
->trace_tail
= trace_next_page(data
, data
->trace_tail
);
739 data
->trace_tail_idx
= 0;
742 /* Check if we empty it, then reset the index */
743 if (data
->trace_head
== data
->trace_tail
&&
744 data
->trace_head_idx
== data
->trace_tail_idx
)
747 trace_iterator_increment(iter
);
750 static notrace
void *
751 find_next_entry_inc(struct trace_iterator
*iter
)
753 struct trace_entry
*next
;
756 next
= find_next_entry(iter
, &next_cpu
);
758 iter
->prev_ent
= iter
->ent
;
759 iter
->prev_cpu
= iter
->cpu
;
762 iter
->cpu
= next_cpu
;
765 trace_iterator_increment(iter
);
767 return next
? iter
: NULL
;
770 static notrace
void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
772 struct trace_iterator
*iter
= m
->private;
773 void *last_ent
= iter
->ent
;
779 /* can't go backwards */
784 ent
= find_next_entry_inc(iter
);
788 while (ent
&& iter
->idx
< i
)
789 ent
= find_next_entry_inc(iter
);
793 if (last_ent
&& !ent
)
794 seq_puts(m
, "\n\nvim:ft=help\n");
799 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
801 struct trace_iterator
*iter
= m
->private;
806 mutex_lock(&trace_types_lock
);
808 if (!current_trace
|| current_trace
!= iter
->trace
)
811 atomic_inc(&trace_record_cmdline_disabled
);
813 /* let the tracer grab locks here if needed */
814 if (current_trace
->start
)
815 current_trace
->start(iter
);
817 if (*pos
!= iter
->pos
) {
821 iter
->prev_ent
= NULL
;
824 for_each_possible_cpu(i
) {
825 iter
->next_idx
[i
] = 0;
826 iter
->next_page
[i
] = NULL
;
829 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
834 p
= s_next(m
, p
, &l
);
840 static void s_stop(struct seq_file
*m
, void *p
)
842 struct trace_iterator
*iter
= m
->private;
844 atomic_dec(&trace_record_cmdline_disabled
);
846 /* let the tracer release locks here if needed */
847 if (current_trace
&& current_trace
== iter
->trace
&& iter
->trace
->stop
)
848 iter
->trace
->stop(iter
);
850 mutex_unlock(&trace_types_lock
);
854 seq_print_sym_short(struct trace_seq
*s
, const char *fmt
, unsigned long address
)
856 #ifdef CONFIG_KALLSYMS
857 char str
[KSYM_SYMBOL_LEN
];
859 kallsyms_lookup(address
, NULL
, NULL
, NULL
, str
);
861 return trace_seq_printf(s
, fmt
, str
);
867 seq_print_sym_offset(struct trace_seq
*s
, const char *fmt
,
868 unsigned long address
)
870 #ifdef CONFIG_KALLSYMS
871 char str
[KSYM_SYMBOL_LEN
];
873 sprint_symbol(str
, address
);
874 return trace_seq_printf(s
, fmt
, str
);
880 # define IP_FMT "%08lx"
882 # define IP_FMT "%016lx"
886 seq_print_ip_sym(struct trace_seq
*s
, unsigned long ip
, unsigned long sym_flags
)
891 return trace_seq_printf(s
, "0");
893 if (sym_flags
& TRACE_ITER_SYM_OFFSET
)
894 ret
= seq_print_sym_offset(s
, "%s", ip
);
896 ret
= seq_print_sym_short(s
, "%s", ip
);
901 if (sym_flags
& TRACE_ITER_SYM_ADDR
)
902 ret
= trace_seq_printf(s
, " <" IP_FMT
">", ip
);
906 static notrace
void print_lat_help_header(struct seq_file
*m
)
908 seq_puts(m
, "# _------=> CPU# \n");
909 seq_puts(m
, "# / _-----=> irqs-off \n");
910 seq_puts(m
, "# | / _----=> need-resched \n");
911 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
912 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
913 seq_puts(m
, "# |||| / \n");
914 seq_puts(m
, "# ||||| delay \n");
915 seq_puts(m
, "# cmd pid ||||| time | caller \n");
916 seq_puts(m
, "# \\ / ||||| \\ | / \n");
919 static notrace
void print_func_help_header(struct seq_file
*m
)
921 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
922 seq_puts(m
, "# | | | | |\n");
927 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
929 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
930 struct trace_array
*tr
= iter
->tr
;
931 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
932 struct tracer
*type
= current_trace
;
933 unsigned long total
= 0;
934 unsigned long entries
= 0;
936 const char *name
= "preemption";
941 for_each_possible_cpu(cpu
) {
942 if (head_page(tr
->data
[cpu
])) {
943 total
+= tr
->data
[cpu
]->trace_idx
;
944 if (tr
->data
[cpu
]->trace_idx
> tr
->entries
)
945 entries
+= tr
->entries
;
947 entries
+= tr
->data
[cpu
]->trace_idx
;
951 seq_printf(m
, "%s latency trace v1.1.5 on %s\n",
953 seq_puts(m
, "-----------------------------------"
954 "---------------------------------\n");
955 seq_printf(m
, " latency: %lu us, #%lu/%lu, CPU#%d |"
956 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
957 nsecs_to_usecs(data
->saved_latency
),
961 #if defined(CONFIG_PREEMPT_NONE)
963 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
965 #elif defined(CONFIG_PREEMPT_DESKTOP)
970 /* These are reserved for later use */
973 seq_printf(m
, " #P:%d)\n", num_online_cpus());
977 seq_puts(m
, " -----------------\n");
978 seq_printf(m
, " | task: %.16s-%d "
979 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
980 data
->comm
, data
->pid
, data
->uid
, data
->nice
,
981 data
->policy
, data
->rt_priority
);
982 seq_puts(m
, " -----------------\n");
984 if (data
->critical_start
) {
985 seq_puts(m
, " => started at: ");
986 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
987 trace_print_seq(m
, &iter
->seq
);
988 seq_puts(m
, "\n => ended at: ");
989 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
990 trace_print_seq(m
, &iter
->seq
);
998 lat_print_generic(struct trace_seq
*s
, struct trace_entry
*entry
, int cpu
)
1000 int hardirq
, softirq
;
1003 comm
= trace_find_cmdline(entry
->pid
);
1005 trace_seq_printf(s
, "%8.8s-%-5d ", comm
, entry
->pid
);
1006 trace_seq_printf(s
, "%d", cpu
);
1007 trace_seq_printf(s
, "%c%c",
1008 (entry
->flags
& TRACE_FLAG_IRQS_OFF
) ? 'd' : '.',
1009 ((entry
->flags
& TRACE_FLAG_NEED_RESCHED
) ? 'N' : '.'));
1011 hardirq
= entry
->flags
& TRACE_FLAG_HARDIRQ
;
1012 softirq
= entry
->flags
& TRACE_FLAG_SOFTIRQ
;
1013 if (hardirq
&& softirq
)
1014 trace_seq_putc(s
, 'H');
1017 trace_seq_putc(s
, 'h');
1020 trace_seq_putc(s
, 's');
1022 trace_seq_putc(s
, '.');
1026 if (entry
->preempt_count
)
1027 trace_seq_printf(s
, "%x", entry
->preempt_count
);
1029 trace_seq_puts(s
, ".");
1032 unsigned long preempt_mark_thresh
= 100;
1035 lat_print_timestamp(struct trace_seq
*s
, unsigned long long abs_usecs
,
1036 unsigned long rel_usecs
)
1038 trace_seq_printf(s
, " %4lldus", abs_usecs
);
1039 if (rel_usecs
> preempt_mark_thresh
)
1040 trace_seq_puts(s
, "!: ");
1041 else if (rel_usecs
> 1)
1042 trace_seq_puts(s
, "+: ");
1044 trace_seq_puts(s
, " : ");
1047 static const char state_to_char
[] = TASK_STATE_TO_CHAR_STR
;
1050 print_lat_fmt(struct trace_iterator
*iter
, unsigned int trace_idx
, int cpu
)
1052 struct trace_seq
*s
= &iter
->seq
;
1053 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1054 struct trace_entry
*next_entry
= find_next_entry(iter
, NULL
);
1055 unsigned long verbose
= (trace_flags
& TRACE_ITER_VERBOSE
);
1056 struct trace_entry
*entry
= iter
->ent
;
1057 unsigned long abs_usecs
;
1058 unsigned long rel_usecs
;
1064 rel_usecs
= ns2usecs(next_entry
->t
- entry
->t
);
1065 abs_usecs
= ns2usecs(entry
->t
- iter
->tr
->time_start
);
1068 comm
= trace_find_cmdline(entry
->pid
);
1069 trace_seq_printf(s
, "%16s %5d %d %d %08x %08x [%08lx]"
1070 " %ld.%03ldms (+%ld.%03ldms): ",
1072 entry
->pid
, cpu
, entry
->flags
,
1073 entry
->preempt_count
, trace_idx
,
1076 abs_usecs
% 1000, rel_usecs
/1000,
1079 lat_print_generic(s
, entry
, cpu
);
1080 lat_print_timestamp(s
, abs_usecs
, rel_usecs
);
1082 switch (entry
->type
) {
1084 seq_print_ip_sym(s
, entry
->fn
.ip
, sym_flags
);
1085 trace_seq_puts(s
, " (");
1086 seq_print_ip_sym(s
, entry
->fn
.parent_ip
, sym_flags
);
1087 trace_seq_puts(s
, ")\n");
1090 S
= entry
->ctx
.prev_state
< sizeof(state_to_char
) ?
1091 state_to_char
[entry
->ctx
.prev_state
] : 'X';
1092 comm
= trace_find_cmdline(entry
->ctx
.next_pid
);
1093 trace_seq_printf(s
, " %d:%d:%c --> %d:%d %s\n",
1094 entry
->ctx
.prev_pid
,
1095 entry
->ctx
.prev_prio
,
1097 entry
->ctx
.next_pid
,
1098 entry
->ctx
.next_prio
,
1102 trace_seq_printf(s
, "Unknown type %d\n", entry
->type
);
1106 static notrace
void sync_time_offset(struct trace_iterator
*iter
)
1108 struct trace_array_cpu
*prev_array
, *array
;
1109 struct trace_entry
*prev_entry
, *entry
;
1113 prev_entry
= iter
->prev_ent
;
1117 prev_array
= iter
->tr
->data
[iter
->prev_cpu
];
1118 array
= iter
->tr
->data
[iter
->cpu
];
1120 prev_t
= prev_entry
->t
+ prev_array
->time_offset
;
1121 t
= entry
->t
+ array
->time_offset
;
1124 * If time goes backwards we increase the offset of
1125 * the current array, to not have observable time warps.
1126 * This will quickly synchronize the time offsets of
1130 array
->time_offset
+= prev_t
- t
;
1134 print_trace_fmt(struct trace_iterator
*iter
)
1136 struct trace_seq
*s
= &iter
->seq
;
1137 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1138 struct trace_entry
*entry
;
1139 unsigned long usec_rem
;
1140 unsigned long long t
;
1146 sync_time_offset(iter
);
1149 comm
= trace_find_cmdline(iter
->ent
->pid
);
1151 t
= ns2usecs(entry
->t
+ iter
->tr
->data
[iter
->cpu
]->time_offset
);
1152 usec_rem
= do_div(t
, 1000000ULL);
1153 secs
= (unsigned long)t
;
1155 ret
= trace_seq_printf(s
, "%16s-%-5d ", comm
, entry
->pid
);
1158 ret
= trace_seq_printf(s
, "[%02d] ", iter
->cpu
);
1161 ret
= trace_seq_printf(s
, "%5lu.%06lu: ", secs
, usec_rem
);
1165 switch (entry
->type
) {
1167 ret
= seq_print_ip_sym(s
, entry
->fn
.ip
, sym_flags
);
1170 if ((sym_flags
& TRACE_ITER_PRINT_PARENT
) &&
1171 entry
->fn
.parent_ip
) {
1172 ret
= trace_seq_printf(s
, " <-");
1175 ret
= seq_print_ip_sym(s
, entry
->fn
.parent_ip
,
1180 ret
= trace_seq_printf(s
, "\n");
1185 S
= entry
->ctx
.prev_state
< sizeof(state_to_char
) ?
1186 state_to_char
[entry
->ctx
.prev_state
] : 'X';
1187 ret
= trace_seq_printf(s
, " %d:%d:%c ==> %d:%d\n",
1188 entry
->ctx
.prev_pid
,
1189 entry
->ctx
.prev_prio
,
1191 entry
->ctx
.next_pid
,
1192 entry
->ctx
.next_prio
);
1200 static int trace_empty(struct trace_iterator
*iter
)
1202 struct trace_array_cpu
*data
;
1205 for_each_possible_cpu(cpu
) {
1206 data
= iter
->tr
->data
[cpu
];
1208 if (head_page(data
) && data
->trace_idx
&&
1209 (data
->trace_tail
!= data
->trace_head
||
1210 data
->trace_tail_idx
!= data
->trace_head_idx
))
1216 static int s_show(struct seq_file
*m
, void *v
)
1218 struct trace_iterator
*iter
= v
;
1220 if (iter
->ent
== NULL
) {
1222 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
1225 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1226 /* print nothing if the buffers are empty */
1227 if (trace_empty(iter
))
1229 print_trace_header(m
, iter
);
1230 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1231 print_lat_help_header(m
);
1233 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1234 print_func_help_header(m
);
1237 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
)
1238 print_lat_fmt(iter
, iter
->idx
, iter
->cpu
);
1240 print_trace_fmt(iter
);
1241 trace_print_seq(m
, &iter
->seq
);
1247 static struct seq_operations tracer_seq_ops
= {
1254 static struct trace_iterator notrace
*
1255 __tracing_open(struct inode
*inode
, struct file
*file
, int *ret
)
1257 struct trace_iterator
*iter
;
1259 if (tracing_disabled
) {
1264 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
1270 mutex_lock(&trace_types_lock
);
1271 if (current_trace
&& current_trace
->print_max
)
1274 iter
->tr
= inode
->i_private
;
1275 iter
->trace
= current_trace
;
1278 /* TODO stop tracer */
1279 *ret
= seq_open(file
, &tracer_seq_ops
);
1281 struct seq_file
*m
= file
->private_data
;
1284 /* stop the trace while dumping */
1288 if (iter
->trace
&& iter
->trace
->open
)
1289 iter
->trace
->open(iter
);
1294 mutex_unlock(&trace_types_lock
);
1300 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
1302 if (tracing_disabled
)
1305 filp
->private_data
= inode
->i_private
;
1309 int tracing_release(struct inode
*inode
, struct file
*file
)
1311 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
1312 struct trace_iterator
*iter
= m
->private;
1314 mutex_lock(&trace_types_lock
);
1315 if (iter
->trace
&& iter
->trace
->close
)
1316 iter
->trace
->close(iter
);
1318 /* reenable tracing if it was previously enabled */
1321 mutex_unlock(&trace_types_lock
);
1323 seq_release(inode
, file
);
1328 static int tracing_open(struct inode
*inode
, struct file
*file
)
1332 __tracing_open(inode
, file
, &ret
);
1337 static int tracing_lt_open(struct inode
*inode
, struct file
*file
)
1339 struct trace_iterator
*iter
;
1342 iter
= __tracing_open(inode
, file
, &ret
);
1345 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
1351 static notrace
void *
1352 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1354 struct tracer
*t
= m
->private;
1366 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
1368 struct tracer
*t
= m
->private;
1371 mutex_lock(&trace_types_lock
);
1372 for (; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
1378 static void t_stop(struct seq_file
*m
, void *p
)
1380 mutex_unlock(&trace_types_lock
);
1383 static int t_show(struct seq_file
*m
, void *v
)
1385 struct tracer
*t
= v
;
1390 seq_printf(m
, "%s", t
->name
);
1399 static struct seq_operations show_traces_seq_ops
= {
1406 static int show_traces_open(struct inode
*inode
, struct file
*file
)
1410 if (tracing_disabled
)
1413 ret
= seq_open(file
, &show_traces_seq_ops
);
1415 struct seq_file
*m
= file
->private_data
;
1416 m
->private = trace_types
;
1422 static struct file_operations tracing_fops
= {
1423 .open
= tracing_open
,
1425 .llseek
= seq_lseek
,
1426 .release
= tracing_release
,
1429 static struct file_operations tracing_lt_fops
= {
1430 .open
= tracing_lt_open
,
1432 .llseek
= seq_lseek
,
1433 .release
= tracing_release
,
1436 static struct file_operations show_traces_fops
= {
1437 .open
= show_traces_open
,
1439 .release
= seq_release
,
1443 tracing_iter_ctrl_read(struct file
*filp
, char __user
*ubuf
,
1444 size_t cnt
, loff_t
*ppos
)
1451 /* calulate max size */
1452 for (i
= 0; trace_options
[i
]; i
++) {
1453 len
+= strlen(trace_options
[i
]);
1454 len
+= 3; /* "no" and space */
1457 /* +2 for \n and \0 */
1458 buf
= kmalloc(len
+ 2, GFP_KERNEL
);
1462 for (i
= 0; trace_options
[i
]; i
++) {
1463 if (trace_flags
& (1 << i
))
1464 r
+= sprintf(buf
+ r
, "%s ", trace_options
[i
]);
1466 r
+= sprintf(buf
+ r
, "no%s ", trace_options
[i
]);
1469 r
+= sprintf(buf
+ r
, "\n");
1470 WARN_ON(r
>= len
+ 2);
1472 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
1481 tracing_iter_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
1482 size_t cnt
, loff_t
*ppos
)
1492 if (copy_from_user(&buf
, ubuf
, cnt
))
1497 if (strncmp(buf
, "no", 2) == 0) {
1502 for (i
= 0; trace_options
[i
]; i
++) {
1503 int len
= strlen(trace_options
[i
]);
1505 if (strncmp(cmp
, trace_options
[i
], len
) == 0) {
1507 trace_flags
&= ~(1 << i
);
1509 trace_flags
|= (1 << i
);
1519 static struct file_operations tracing_iter_fops
= {
1520 .open
= tracing_open_generic
,
1521 .read
= tracing_iter_ctrl_read
,
1522 .write
= tracing_iter_ctrl_write
,
1525 static const char readme_msg
[] =
1526 "tracing mini-HOWTO:\n\n"
1528 "# mount -t debugfs nodev /debug\n\n"
1529 "# cat /debug/tracing/available_tracers\n"
1530 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
1531 "# cat /debug/tracing/current_tracer\n"
1533 "# echo sched_switch > /debug/tracing/current_tracer\n"
1534 "# cat /debug/tracing/current_tracer\n"
1536 "# cat /debug/tracing/iter_ctrl\n"
1537 "noprint-parent nosym-offset nosym-addr noverbose\n"
1538 "# echo print-parent > /debug/tracing/iter_ctrl\n"
1539 "# echo 1 > /debug/tracing/tracing_enabled\n"
1540 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
1541 "echo 0 > /debug/tracing/tracing_enabled\n"
1545 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
1546 size_t cnt
, loff_t
*ppos
)
1548 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
1549 readme_msg
, strlen(readme_msg
));
1552 static struct file_operations tracing_readme_fops
= {
1553 .open
= tracing_open_generic
,
1554 .read
= tracing_readme_read
,
1559 tracing_ctrl_read(struct file
*filp
, char __user
*ubuf
,
1560 size_t cnt
, loff_t
*ppos
)
1562 struct trace_array
*tr
= filp
->private_data
;
1566 r
= sprintf(buf
, "%ld\n", tr
->ctrl
);
1567 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
1571 tracing_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
1572 size_t cnt
, loff_t
*ppos
)
1574 struct trace_array
*tr
= filp
->private_data
;
1581 if (copy_from_user(&buf
, ubuf
, cnt
))
1586 val
= simple_strtoul(buf
, NULL
, 10);
1590 mutex_lock(&trace_types_lock
);
1591 if (tr
->ctrl
^ val
) {
1599 if (current_trace
&& current_trace
->ctrl_update
)
1600 current_trace
->ctrl_update(tr
);
1602 mutex_unlock(&trace_types_lock
);
1610 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
1611 size_t cnt
, loff_t
*ppos
)
1613 char buf
[max_tracer_type_len
+2];
1616 mutex_lock(&trace_types_lock
);
1618 r
= sprintf(buf
, "%s\n", current_trace
->name
);
1620 r
= sprintf(buf
, "\n");
1621 mutex_unlock(&trace_types_lock
);
1623 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
1628 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
1629 size_t cnt
, loff_t
*ppos
)
1631 struct trace_array
*tr
= &global_trace
;
1633 char buf
[max_tracer_type_len
+1];
1636 if (cnt
> max_tracer_type_len
)
1637 cnt
= max_tracer_type_len
;
1639 if (copy_from_user(&buf
, ubuf
, cnt
))
1644 /* strip ending whitespace. */
1645 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
1648 mutex_lock(&trace_types_lock
);
1649 for (t
= trace_types
; t
; t
= t
->next
) {
1650 if (strcmp(t
->name
, buf
) == 0)
1653 if (!t
|| t
== current_trace
)
1656 if (current_trace
&& current_trace
->reset
)
1657 current_trace
->reset(tr
);
1664 mutex_unlock(&trace_types_lock
);
1672 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
1673 size_t cnt
, loff_t
*ppos
)
1675 unsigned long *ptr
= filp
->private_data
;
1679 r
= snprintf(buf
, 64, "%ld\n",
1680 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
1683 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
1688 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
1689 size_t cnt
, loff_t
*ppos
)
1691 long *ptr
= filp
->private_data
;
1698 if (copy_from_user(&buf
, ubuf
, cnt
))
1703 val
= simple_strtoul(buf
, NULL
, 10);
1710 static atomic_t tracing_reader
;
1712 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
1714 struct trace_iterator
*iter
;
1716 if (tracing_disabled
)
1719 /* We only allow for reader of the pipe */
1720 if (atomic_inc_return(&tracing_reader
) != 1) {
1721 atomic_dec(&tracing_reader
);
1725 /* create a buffer to store the information to pass to userspace */
1726 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
1730 iter
->tr
= &global_trace
;
1732 filp
->private_data
= iter
;
1737 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
1739 struct trace_iterator
*iter
= file
->private_data
;
1742 atomic_dec(&tracing_reader
);
1751 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
1752 size_t cnt
, loff_t
*ppos
)
1754 struct trace_iterator
*iter
= filp
->private_data
;
1755 struct trace_array_cpu
*data
;
1756 static cpumask_t mask
;
1757 struct trace_entry
*entry
;
1759 unsigned long flags
;
1765 /* return any leftover data */
1766 if (iter
->seq
.len
> start
) {
1767 len
= iter
->seq
.len
- start
;
1770 ret
= copy_to_user(ubuf
, iter
->seq
.buffer
+ start
, cnt
);
1779 trace_seq_reset(&iter
->seq
);
1782 while (trace_empty(iter
)) {
1784 * This is a make-shift waitqueue. The reason we don't use
1785 * an actual wait queue is because:
1786 * 1) we only ever have one waiter
1787 * 2) the tracing, traces all functions, we don't want
1788 * the overhead of calling wake_up and friends
1789 * (and tracing them too)
1790 * Anyway, this is really very primitive wakeup.
1792 set_current_state(TASK_INTERRUPTIBLE
);
1793 iter
->tr
->waiter
= current
;
1795 /* sleep for one second, and try again. */
1796 schedule_timeout(HZ
);
1798 iter
->tr
->waiter
= NULL
;
1800 if (signal_pending(current
))
1804 * We block until we read something and tracing is disabled.
1805 * We still block if tracing is disabled, but we have never
1806 * read anything. This allows a user to cat this file, and
1807 * then enable tracing. But after we have read something,
1808 * we give an EOF when tracing is again disabled.
1810 * iter->pos will be 0 if we haven't read anything.
1812 if (!tracer_enabled
&& iter
->pos
)
1818 /* stop when tracing is finished */
1819 if (trace_empty(iter
))
1822 if (cnt
>= PAGE_SIZE
)
1823 cnt
= PAGE_SIZE
- 1;
1825 memset(iter
, 0, sizeof(*iter
));
1826 iter
->tr
= &global_trace
;
1830 * We need to stop all tracing on all CPUS to read the
1831 * the next buffer. This is a bit expensive, but is
1832 * not done often. We fill all what we can read,
1833 * and then release the locks again.
1837 local_irq_save(flags
);
1838 for_each_possible_cpu(cpu
) {
1839 data
= iter
->tr
->data
[cpu
];
1841 if (!head_page(data
) || !data
->trace_idx
)
1844 atomic_inc(&data
->disabled
);
1845 spin_lock(&data
->lock
);
1849 while ((entry
= find_next_entry(iter
, &cpu
))) {
1857 ret
= print_trace_fmt(iter
);
1861 trace_consume(iter
);
1863 if (iter
->seq
.len
>= cnt
)
1868 for_each_possible_cpu(cpu
) {
1869 data
= iter
->tr
->data
[cpu
];
1871 if (!cpu_isset(cpu
, mask
))
1873 spin_unlock(&data
->lock
);
1874 atomic_dec(&data
->disabled
);
1876 local_irq_restore(flags
);
1878 /* Now copy what we have to the user */
1879 read
= iter
->seq
.len
;
1883 ret
= copy_to_user(ubuf
, iter
->seq
.buffer
, read
);
1885 if (read
< iter
->seq
.len
)
1888 trace_seq_reset(&iter
->seq
);
1896 static struct file_operations tracing_max_lat_fops
= {
1897 .open
= tracing_open_generic
,
1898 .read
= tracing_max_lat_read
,
1899 .write
= tracing_max_lat_write
,
1902 static struct file_operations tracing_ctrl_fops
= {
1903 .open
= tracing_open_generic
,
1904 .read
= tracing_ctrl_read
,
1905 .write
= tracing_ctrl_write
,
1908 static struct file_operations set_tracer_fops
= {
1909 .open
= tracing_open_generic
,
1910 .read
= tracing_set_trace_read
,
1911 .write
= tracing_set_trace_write
,
1914 static struct file_operations tracing_pipe_fops
= {
1915 .open
= tracing_open_pipe
,
1916 .read
= tracing_read_pipe
,
1917 .release
= tracing_release_pipe
,
1920 #ifdef CONFIG_DYNAMIC_FTRACE
1923 tracing_read_long(struct file
*filp
, char __user
*ubuf
,
1924 size_t cnt
, loff_t
*ppos
)
1926 unsigned long *p
= filp
->private_data
;
1930 r
= sprintf(buf
, "%ld\n", *p
);
1931 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
1935 static struct file_operations tracing_read_long_fops
= {
1936 .open
= tracing_open_generic
,
1937 .read
= tracing_read_long
,
1941 static struct dentry
*d_tracer
;
1943 struct dentry
*tracing_init_dentry(void)
1950 d_tracer
= debugfs_create_dir("tracing", NULL
);
1952 if (!d_tracer
&& !once
) {
1954 pr_warning("Could not create debugfs directory 'tracing'\n");
1961 #ifdef CONFIG_FTRACE_SELFTEST
1962 /* Let selftest have access to static functions in this file */
1963 #include "trace_selftest.c"
1966 static __init
void tracer_init_debugfs(void)
1968 struct dentry
*d_tracer
;
1969 struct dentry
*entry
;
1971 d_tracer
= tracing_init_dentry();
1973 entry
= debugfs_create_file("tracing_enabled", 0644, d_tracer
,
1974 &global_trace
, &tracing_ctrl_fops
);
1976 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
1978 entry
= debugfs_create_file("iter_ctrl", 0644, d_tracer
,
1979 NULL
, &tracing_iter_fops
);
1981 pr_warning("Could not create debugfs 'iter_ctrl' entry\n");
1983 entry
= debugfs_create_file("latency_trace", 0444, d_tracer
,
1984 &global_trace
, &tracing_lt_fops
);
1986 pr_warning("Could not create debugfs 'latency_trace' entry\n");
1988 entry
= debugfs_create_file("trace", 0444, d_tracer
,
1989 &global_trace
, &tracing_fops
);
1991 pr_warning("Could not create debugfs 'trace' entry\n");
1993 entry
= debugfs_create_file("available_tracers", 0444, d_tracer
,
1994 &global_trace
, &show_traces_fops
);
1996 pr_warning("Could not create debugfs 'trace' entry\n");
1998 entry
= debugfs_create_file("current_tracer", 0444, d_tracer
,
1999 &global_trace
, &set_tracer_fops
);
2001 pr_warning("Could not create debugfs 'trace' entry\n");
2003 entry
= debugfs_create_file("tracing_max_latency", 0644, d_tracer
,
2004 &tracing_max_latency
,
2005 &tracing_max_lat_fops
);
2007 pr_warning("Could not create debugfs "
2008 "'tracing_max_latency' entry\n");
2010 entry
= debugfs_create_file("tracing_thresh", 0644, d_tracer
,
2011 &tracing_thresh
, &tracing_max_lat_fops
);
2013 pr_warning("Could not create debugfs "
2014 "'tracing_threash' entry\n");
2015 entry
= debugfs_create_file("README", 0644, d_tracer
,
2016 NULL
, &tracing_readme_fops
);
2018 pr_warning("Could not create debugfs 'README' entry\n");
2020 entry
= debugfs_create_file("trace_pipe", 0644, d_tracer
,
2021 NULL
, &tracing_pipe_fops
);
2023 pr_warning("Could not create debugfs "
2024 "'tracing_threash' entry\n");
2026 #ifdef CONFIG_DYNAMIC_FTRACE
2027 entry
= debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
2028 &ftrace_update_tot_cnt
,
2029 &tracing_read_long_fops
);
2031 pr_warning("Could not create debugfs "
2032 "'dyn_ftrace_total_info' entry\n");
2036 /* dummy trace to disable tracing */
2037 static struct tracer no_tracer __read_mostly
=
2042 static int trace_alloc_page(void)
2044 struct trace_array_cpu
*data
;
2045 struct page
*page
, *tmp
;
2050 /* first allocate a page for each CPU */
2051 for_each_possible_cpu(i
) {
2052 array
= (void *)__get_free_page(GFP_KERNEL
);
2053 if (array
== NULL
) {
2054 printk(KERN_ERR
"tracer: failed to allocate page"
2055 "for trace buffer!\n");
2059 page
= virt_to_page(array
);
2060 list_add(&page
->lru
, &pages
);
2062 /* Only allocate if we are actually using the max trace */
2063 #ifdef CONFIG_TRACER_MAX_TRACE
2064 array
= (void *)__get_free_page(GFP_KERNEL
);
2065 if (array
== NULL
) {
2066 printk(KERN_ERR
"tracer: failed to allocate page"
2067 "for trace buffer!\n");
2070 page
= virt_to_page(array
);
2071 list_add(&page
->lru
, &pages
);
2075 /* Now that we successfully allocate a page per CPU, add them */
2076 for_each_possible_cpu(i
) {
2077 data
= global_trace
.data
[i
];
2078 spin_lock_init(&data
->lock
);
2079 page
= list_entry(pages
.next
, struct page
, lru
);
2080 list_del_init(&page
->lru
);
2081 list_add_tail(&page
->lru
, &data
->trace_pages
);
2084 #ifdef CONFIG_TRACER_MAX_TRACE
2085 data
= max_tr
.data
[i
];
2086 spin_lock_init(&data
->lock
);
2087 page
= list_entry(pages
.next
, struct page
, lru
);
2088 list_del_init(&page
->lru
);
2089 list_add_tail(&page
->lru
, &data
->trace_pages
);
2093 global_trace
.entries
+= ENTRIES_PER_PAGE
;
2098 list_for_each_entry_safe(page
, tmp
, &pages
, lru
) {
2099 list_del_init(&page
->lru
);
2105 __init
static int tracer_alloc_buffers(void)
2107 struct trace_array_cpu
*data
;
2114 /* Allocate the first page for all buffers */
2115 for_each_possible_cpu(i
) {
2116 data
= global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
2117 max_tr
.data
[i
] = &per_cpu(max_data
, i
);
2119 array
= (void *)__get_free_page(GFP_KERNEL
);
2120 if (array
== NULL
) {
2121 printk(KERN_ERR
"tracer: failed to allocate page"
2122 "for trace buffer!\n");
2126 /* set the array to the list */
2127 INIT_LIST_HEAD(&data
->trace_pages
);
2128 page
= virt_to_page(array
);
2129 list_add(&page
->lru
, &data
->trace_pages
);
2130 /* use the LRU flag to differentiate the two buffers */
2133 /* Only allocate if we are actually using the max trace */
2134 #ifdef CONFIG_TRACER_MAX_TRACE
2135 array
= (void *)__get_free_page(GFP_KERNEL
);
2136 if (array
== NULL
) {
2137 printk(KERN_ERR
"tracer: failed to allocate page"
2138 "for trace buffer!\n");
2142 INIT_LIST_HEAD(&max_tr
.data
[i
]->trace_pages
);
2143 page
= virt_to_page(array
);
2144 list_add(&page
->lru
, &max_tr
.data
[i
]->trace_pages
);
2150 * Since we allocate by orders of pages, we may be able to
2153 global_trace
.entries
= ENTRIES_PER_PAGE
;
2156 while (global_trace
.entries
< trace_nr_entries
) {
2157 if (trace_alloc_page())
2161 max_tr
.entries
= global_trace
.entries
;
2163 pr_info("tracer: %d pages allocated for %ld",
2164 pages
, trace_nr_entries
);
2165 pr_info(" entries of %ld bytes\n", (long)TRACE_ENTRY_SIZE
);
2166 pr_info(" actual entries %ld\n", global_trace
.entries
);
2168 tracer_init_debugfs();
2170 trace_init_cmdlines();
2172 register_tracer(&no_tracer
);
2173 current_trace
= &no_tracer
;
2175 /* All seems OK, enable tracing */
2176 tracing_disabled
= 0;
2181 for (i
-- ; i
>= 0; i
--) {
2182 struct page
*page
, *tmp
;
2183 struct trace_array_cpu
*data
= global_trace
.data
[i
];
2186 list_for_each_entry_safe(page
, tmp
,
2187 &data
->trace_pages
, lru
) {
2188 list_del_init(&page
->lru
);
2193 #ifdef CONFIG_TRACER_MAX_TRACE
2194 data
= max_tr
.data
[i
];
2196 list_for_each_entry_safe(page
, tmp
,
2197 &data
->trace_pages
, lru
) {
2198 list_del_init(&page
->lru
);
2207 fs_initcall(tracer_alloc_buffers
);