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/poll.h>
28 #include <linux/gfp.h>
33 unsigned long __read_mostly tracing_max_latency
= (cycle_t
)ULONG_MAX
;
34 unsigned long __read_mostly tracing_thresh
;
36 static int tracing_disabled
= 1;
39 ns2usecs(cycle_t nsec
)
46 cycle_t
ftrace_now(int cpu
)
48 return cpu_clock(cpu
);
51 static struct trace_array global_trace
;
53 static DEFINE_PER_CPU(struct trace_array_cpu
, global_trace_cpu
);
55 static struct trace_array max_tr
;
57 static DEFINE_PER_CPU(struct trace_array_cpu
, max_data
);
59 static int tracer_enabled
= 1;
60 static unsigned long trace_nr_entries
= 16384UL;
62 static struct tracer
*trace_types __read_mostly
;
63 static struct tracer
*current_trace __read_mostly
;
64 static int max_tracer_type_len
;
66 static DEFINE_MUTEX(trace_types_lock
);
67 static DECLARE_WAIT_QUEUE_HEAD (trace_wait
);
69 #define ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(struct trace_entry))
71 static int __init
set_nr_entries(char *str
)
75 trace_nr_entries
= simple_strtoul(str
, &str
, 0);
78 __setup("trace_entries=", set_nr_entries
);
80 unsigned long nsecs_to_usecs(unsigned long nsecs
)
86 __TRACE_FIRST_TYPE
= 0,
95 enum trace_flag_type
{
96 TRACE_FLAG_IRQS_OFF
= 0x01,
97 TRACE_FLAG_NEED_RESCHED
= 0x02,
98 TRACE_FLAG_HARDIRQ
= 0x04,
99 TRACE_FLAG_SOFTIRQ
= 0x08,
102 enum trace_iterator_flags
{
103 TRACE_ITER_PRINT_PARENT
= 0x01,
104 TRACE_ITER_SYM_OFFSET
= 0x02,
105 TRACE_ITER_SYM_ADDR
= 0x04,
106 TRACE_ITER_VERBOSE
= 0x08,
107 TRACE_ITER_RAW
= 0x10,
108 TRACE_ITER_HEX
= 0x20,
109 TRACE_ITER_BIN
= 0x40,
110 TRACE_ITER_BLOCK
= 0x80,
113 #define TRACE_ITER_SYM_MASK \
114 (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
116 /* These must match the bit postions above */
117 static const char *trace_options
[] = {
129 static unsigned trace_flags
;
131 static DEFINE_SPINLOCK(ftrace_max_lock
);
134 * Copy the new maximum trace into the separate maximum-trace
135 * structure. (this way the maximum trace is permanently saved,
136 * for later retrieval via /debugfs/tracing/latency_trace)
139 __update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
141 struct trace_array_cpu
*data
= tr
->data
[cpu
];
144 max_tr
.time_start
= data
->preempt_timestamp
;
146 data
= max_tr
.data
[cpu
];
147 data
->saved_latency
= tracing_max_latency
;
149 memcpy(data
->comm
, tsk
->comm
, TASK_COMM_LEN
);
150 data
->pid
= tsk
->pid
;
151 data
->uid
= tsk
->uid
;
152 data
->nice
= tsk
->static_prio
- 20 - MAX_RT_PRIO
;
153 data
->policy
= tsk
->policy
;
154 data
->rt_priority
= tsk
->rt_priority
;
156 /* record this tasks comm */
157 tracing_record_cmdline(current
);
160 void check_pages(struct trace_array_cpu
*data
)
162 struct page
*page
, *tmp
;
164 BUG_ON(data
->trace_pages
.next
->prev
!= &data
->trace_pages
);
165 BUG_ON(data
->trace_pages
.prev
->next
!= &data
->trace_pages
);
167 list_for_each_entry_safe(page
, tmp
, &data
->trace_pages
, lru
) {
168 BUG_ON(page
->lru
.next
->prev
!= &page
->lru
);
169 BUG_ON(page
->lru
.prev
->next
!= &page
->lru
);
173 void *head_page(struct trace_array_cpu
*data
)
178 if (list_empty(&data
->trace_pages
))
181 page
= list_entry(data
->trace_pages
.next
, struct page
, lru
);
182 BUG_ON(&page
->lru
== &data
->trace_pages
);
184 return page_address(page
);
188 trace_seq_printf(struct trace_seq
*s
, const char *fmt
, ...)
190 int len
= (PAGE_SIZE
- 1) - s
->len
;
198 ret
= vsnprintf(s
->buffer
+ s
->len
, len
, fmt
, ap
);
201 /* If we can't write it all, don't bother writing anything */
211 trace_seq_puts(struct trace_seq
*s
, const char *str
)
213 int len
= strlen(str
);
215 if (len
> ((PAGE_SIZE
- 1) - s
->len
))
218 memcpy(s
->buffer
+ s
->len
, str
, len
);
225 trace_seq_putc(struct trace_seq
*s
, unsigned char c
)
227 if (s
->len
>= (PAGE_SIZE
- 1))
230 s
->buffer
[s
->len
++] = c
;
236 trace_seq_putmem(struct trace_seq
*s
, void *mem
, size_t len
)
238 if (len
> ((PAGE_SIZE
- 1) - s
->len
))
241 memcpy(s
->buffer
+ s
->len
, mem
, len
);
250 trace_seq_putmem_hex(struct trace_seq
*s
, void *mem
, size_t len
)
252 unsigned char hex
[HEX_CHARS
];
257 BUG_ON(len
>= HEX_CHARS
);
262 for (i
= 0, j
= 0; i
< len
; i
++) {
264 for (i
= len
-1, j
= 0; i
>= 0; i
--) {
268 hex
[j
] = byte
& 0x0f;
285 return trace_seq_putmem(s
, hex
, j
);
289 trace_seq_reset(struct trace_seq
*s
)
295 trace_print_seq(struct seq_file
*m
, struct trace_seq
*s
)
297 int len
= s
->len
>= PAGE_SIZE
? PAGE_SIZE
- 1 : s
->len
;
300 seq_puts(m
, s
->buffer
);
306 flip_trace(struct trace_array_cpu
*tr1
, struct trace_array_cpu
*tr2
)
308 struct list_head flip_pages
;
310 INIT_LIST_HEAD(&flip_pages
);
312 memcpy(&tr1
->trace_head_idx
, &tr2
->trace_head_idx
,
313 sizeof(struct trace_array_cpu
) -
314 offsetof(struct trace_array_cpu
, trace_head_idx
));
318 list_splice_init(&tr1
->trace_pages
, &flip_pages
);
319 list_splice_init(&tr2
->trace_pages
, &tr1
->trace_pages
);
320 list_splice_init(&flip_pages
, &tr2
->trace_pages
);
321 BUG_ON(!list_empty(&flip_pages
));
327 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
329 struct trace_array_cpu
*data
;
332 WARN_ON_ONCE(!irqs_disabled());
333 spin_lock(&ftrace_max_lock
);
334 /* clear out all the previous traces */
335 for_each_possible_cpu(i
) {
337 flip_trace(max_tr
.data
[i
], data
);
341 __update_max_tr(tr
, tsk
, cpu
);
342 spin_unlock(&ftrace_max_lock
);
346 * update_max_tr_single - only copy one trace over, and reset the rest
348 * @tsk - task with the latency
349 * @cpu - the cpu of the buffer to copy.
352 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
354 struct trace_array_cpu
*data
= tr
->data
[cpu
];
357 WARN_ON_ONCE(!irqs_disabled());
358 spin_lock(&ftrace_max_lock
);
359 for_each_possible_cpu(i
)
360 tracing_reset(max_tr
.data
[i
]);
362 flip_trace(max_tr
.data
[cpu
], data
);
365 __update_max_tr(tr
, tsk
, cpu
);
366 spin_unlock(&ftrace_max_lock
);
369 int register_tracer(struct tracer
*type
)
376 pr_info("Tracer must have a name\n");
380 mutex_lock(&trace_types_lock
);
381 for (t
= trace_types
; t
; t
= t
->next
) {
382 if (strcmp(type
->name
, t
->name
) == 0) {
384 pr_info("Trace %s already registered\n",
391 #ifdef CONFIG_FTRACE_STARTUP_TEST
392 if (type
->selftest
) {
393 struct tracer
*saved_tracer
= current_trace
;
394 struct trace_array_cpu
*data
;
395 struct trace_array
*tr
= &global_trace
;
396 int saved_ctrl
= tr
->ctrl
;
399 * Run a selftest on this tracer.
400 * Here we reset the trace buffer, and set the current
401 * tracer to be this tracer. The tracer can then run some
402 * internal tracing to verify that everything is in order.
403 * If we fail, we do not register this tracer.
405 for_each_possible_cpu(i
) {
407 if (!head_page(data
))
411 current_trace
= type
;
413 /* the test is responsible for initializing and enabling */
414 pr_info("Testing tracer %s: ", type
->name
);
415 ret
= type
->selftest(type
, tr
);
416 /* the test is responsible for resetting too */
417 current_trace
= saved_tracer
;
418 tr
->ctrl
= saved_ctrl
;
420 printk(KERN_CONT
"FAILED!\n");
423 /* Only reset on passing, to avoid touching corrupted buffers */
424 for_each_possible_cpu(i
) {
426 if (!head_page(data
))
430 printk(KERN_CONT
"PASSED\n");
434 type
->next
= trace_types
;
436 len
= strlen(type
->name
);
437 if (len
> max_tracer_type_len
)
438 max_tracer_type_len
= len
;
441 mutex_unlock(&trace_types_lock
);
446 void unregister_tracer(struct tracer
*type
)
451 mutex_lock(&trace_types_lock
);
452 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
456 pr_info("Trace %s not registered\n", type
->name
);
461 if (strlen(type
->name
) != max_tracer_type_len
)
464 max_tracer_type_len
= 0;
465 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
466 len
= strlen((*t
)->name
);
467 if (len
> max_tracer_type_len
)
468 max_tracer_type_len
= len
;
471 mutex_unlock(&trace_types_lock
);
474 void tracing_reset(struct trace_array_cpu
*data
)
477 data
->trace_head
= data
->trace_tail
= head_page(data
);
478 data
->trace_head_idx
= 0;
479 data
->trace_tail_idx
= 0;
482 #define SAVED_CMDLINES 128
483 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
484 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
485 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
486 static int cmdline_idx
;
487 static DEFINE_SPINLOCK(trace_cmdline_lock
);
488 atomic_t trace_record_cmdline_disabled
;
490 static void trace_init_cmdlines(void)
492 memset(&map_pid_to_cmdline
, -1, sizeof(map_pid_to_cmdline
));
493 memset(&map_cmdline_to_pid
, -1, sizeof(map_cmdline_to_pid
));
497 void trace_stop_cmdline_recording(void);
499 static void trace_save_cmdline(struct task_struct
*tsk
)
504 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
508 * It's not the end of the world if we don't get
509 * the lock, but we also don't want to spin
510 * nor do we want to disable interrupts,
511 * so if we miss here, then better luck next time.
513 if (!spin_trylock(&trace_cmdline_lock
))
516 idx
= map_pid_to_cmdline
[tsk
->pid
];
517 if (idx
>= SAVED_CMDLINES
) {
518 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
520 map
= map_cmdline_to_pid
[idx
];
521 if (map
<= PID_MAX_DEFAULT
)
522 map_pid_to_cmdline
[map
] = (unsigned)-1;
524 map_pid_to_cmdline
[tsk
->pid
] = idx
;
529 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
531 spin_unlock(&trace_cmdline_lock
);
534 static char *trace_find_cmdline(int pid
)
536 char *cmdline
= "<...>";
542 if (pid
> PID_MAX_DEFAULT
)
545 map
= map_pid_to_cmdline
[pid
];
546 if (map
>= SAVED_CMDLINES
)
549 cmdline
= saved_cmdlines
[map
];
555 void tracing_record_cmdline(struct task_struct
*tsk
)
557 if (atomic_read(&trace_record_cmdline_disabled
))
560 trace_save_cmdline(tsk
);
563 static inline struct list_head
*
564 trace_next_list(struct trace_array_cpu
*data
, struct list_head
*next
)
567 * Roundrobin - but skip the head (which is not a real page):
570 if (unlikely(next
== &data
->trace_pages
))
572 BUG_ON(next
== &data
->trace_pages
);
578 trace_next_page(struct trace_array_cpu
*data
, void *addr
)
580 struct list_head
*next
;
583 page
= virt_to_page(addr
);
585 next
= trace_next_list(data
, &page
->lru
);
586 page
= list_entry(next
, struct page
, lru
);
588 return page_address(page
);
591 static inline struct trace_entry
*
592 tracing_get_trace_entry(struct trace_array
*tr
, struct trace_array_cpu
*data
)
594 unsigned long idx
, idx_next
;
595 struct trace_entry
*entry
;
598 idx
= data
->trace_head_idx
;
601 BUG_ON(idx
* TRACE_ENTRY_SIZE
>= PAGE_SIZE
);
603 entry
= data
->trace_head
+ idx
* TRACE_ENTRY_SIZE
;
605 if (unlikely(idx_next
>= ENTRIES_PER_PAGE
)) {
606 data
->trace_head
= trace_next_page(data
, data
->trace_head
);
610 if (data
->trace_head
== data
->trace_tail
&&
611 idx_next
== data
->trace_tail_idx
) {
613 data
->trace_tail_idx
++;
614 if (data
->trace_tail_idx
>= ENTRIES_PER_PAGE
) {
616 trace_next_page(data
, data
->trace_tail
);
617 data
->trace_tail_idx
= 0;
621 data
->trace_head_idx
= idx_next
;
627 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
)
629 struct task_struct
*tsk
= current
;
632 pc
= preempt_count();
634 entry
->preempt_count
= pc
& 0xff;
635 entry
->pid
= tsk
->pid
;
636 entry
->t
= ftrace_now(raw_smp_processor_id());
637 entry
->flags
= (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
638 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
639 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
640 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
644 trace_function(struct trace_array
*tr
, struct trace_array_cpu
*data
,
645 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
)
647 struct trace_entry
*entry
;
648 unsigned long irq_flags
;
650 spin_lock_irqsave(&data
->lock
, irq_flags
);
651 entry
= tracing_get_trace_entry(tr
, data
);
652 tracing_generic_entry_update(entry
, flags
);
653 entry
->type
= TRACE_FN
;
655 entry
->fn
.parent_ip
= parent_ip
;
656 spin_unlock_irqrestore(&data
->lock
, irq_flags
);
658 if (!(trace_flags
& TRACE_ITER_BLOCK
))
659 wake_up (&trace_wait
);
663 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
664 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
)
666 if (likely(!atomic_read(&data
->disabled
)))
667 trace_function(tr
, data
, ip
, parent_ip
, flags
);
671 trace_special(struct trace_array
*tr
, struct trace_array_cpu
*data
,
672 unsigned long arg1
, unsigned long arg2
, unsigned long arg3
)
674 struct trace_entry
*entry
;
675 unsigned long irq_flags
;
677 spin_lock_irqsave(&data
->lock
, irq_flags
);
678 entry
= tracing_get_trace_entry(tr
, data
);
679 tracing_generic_entry_update(entry
, 0);
680 entry
->type
= TRACE_SPECIAL
;
681 entry
->special
.arg1
= arg1
;
682 entry
->special
.arg2
= arg2
;
683 entry
->special
.arg3
= arg3
;
684 spin_unlock_irqrestore(&data
->lock
, irq_flags
);
686 if (!(trace_flags
& TRACE_ITER_BLOCK
))
687 wake_up (&trace_wait
);
691 tracing_sched_switch_trace(struct trace_array
*tr
,
692 struct trace_array_cpu
*data
,
693 struct task_struct
*prev
, struct task_struct
*next
,
696 struct trace_entry
*entry
;
697 unsigned long irq_flags
;
699 spin_lock_irqsave(&data
->lock
, irq_flags
);
700 entry
= tracing_get_trace_entry(tr
, data
);
701 tracing_generic_entry_update(entry
, flags
);
702 entry
->type
= TRACE_CTX
;
703 entry
->ctx
.prev_pid
= prev
->pid
;
704 entry
->ctx
.prev_prio
= prev
->prio
;
705 entry
->ctx
.prev_state
= prev
->state
;
706 entry
->ctx
.next_pid
= next
->pid
;
707 entry
->ctx
.next_prio
= next
->prio
;
708 spin_unlock_irqrestore(&data
->lock
, irq_flags
);
710 if (!(trace_flags
& TRACE_ITER_BLOCK
))
711 wake_up (&trace_wait
);
716 function_trace_call(unsigned long ip
, unsigned long parent_ip
)
718 struct trace_array
*tr
= &global_trace
;
719 struct trace_array_cpu
*data
;
724 if (unlikely(!tracer_enabled
))
727 local_irq_save(flags
);
728 cpu
= raw_smp_processor_id();
729 data
= tr
->data
[cpu
];
730 disabled
= atomic_inc_return(&data
->disabled
);
732 if (likely(disabled
== 1))
733 trace_function(tr
, data
, ip
, parent_ip
, flags
);
735 atomic_dec(&data
->disabled
);
736 local_irq_restore(flags
);
739 static struct ftrace_ops trace_ops __read_mostly
=
741 .func
= function_trace_call
,
744 void tracing_start_function_trace(void)
746 register_ftrace_function(&trace_ops
);
749 void tracing_stop_function_trace(void)
751 unregister_ftrace_function(&trace_ops
);
755 enum trace_file_type
{
756 TRACE_FILE_LAT_FMT
= 1,
759 static struct trace_entry
*
760 trace_entry_idx(struct trace_array
*tr
, struct trace_array_cpu
*data
,
761 struct trace_iterator
*iter
, int cpu
)
764 struct trace_entry
*array
;
766 if (iter
->next_idx
[cpu
] >= tr
->entries
||
767 iter
->next_idx
[cpu
] >= data
->trace_idx
||
768 (data
->trace_head
== data
->trace_tail
&&
769 data
->trace_head_idx
== data
->trace_tail_idx
))
772 if (!iter
->next_page
[cpu
]) {
773 /* Initialize the iterator for this cpu trace buffer */
774 WARN_ON(!data
->trace_tail
);
775 page
= virt_to_page(data
->trace_tail
);
776 iter
->next_page
[cpu
] = &page
->lru
;
777 iter
->next_page_idx
[cpu
] = data
->trace_tail_idx
;
780 page
= list_entry(iter
->next_page
[cpu
], struct page
, lru
);
781 BUG_ON(&data
->trace_pages
== &page
->lru
);
783 array
= page_address(page
);
785 WARN_ON(iter
->next_page_idx
[cpu
] >= ENTRIES_PER_PAGE
);
786 return &array
[iter
->next_page_idx
[cpu
]];
789 static struct trace_entry
*
790 find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
)
792 struct trace_array
*tr
= iter
->tr
;
793 struct trace_entry
*ent
, *next
= NULL
;
797 for_each_possible_cpu(cpu
) {
798 if (!head_page(tr
->data
[cpu
]))
800 ent
= trace_entry_idx(tr
, tr
->data
[cpu
], iter
, cpu
);
802 * Pick the entry with the smallest timestamp:
804 if (ent
&& (!next
|| ent
->t
< next
->t
)) {
816 static void trace_iterator_increment(struct trace_iterator
*iter
)
819 iter
->next_idx
[iter
->cpu
]++;
820 iter
->next_page_idx
[iter
->cpu
]++;
822 if (iter
->next_page_idx
[iter
->cpu
] >= ENTRIES_PER_PAGE
) {
823 struct trace_array_cpu
*data
= iter
->tr
->data
[iter
->cpu
];
825 iter
->next_page_idx
[iter
->cpu
] = 0;
826 iter
->next_page
[iter
->cpu
] =
827 trace_next_list(data
, iter
->next_page
[iter
->cpu
]);
831 static void trace_consume(struct trace_iterator
*iter
)
833 struct trace_array_cpu
*data
= iter
->tr
->data
[iter
->cpu
];
835 data
->trace_tail_idx
++;
836 if (data
->trace_tail_idx
>= ENTRIES_PER_PAGE
) {
837 data
->trace_tail
= trace_next_page(data
, data
->trace_tail
);
838 data
->trace_tail_idx
= 0;
841 /* Check if we empty it, then reset the index */
842 if (data
->trace_head
== data
->trace_tail
&&
843 data
->trace_head_idx
== data
->trace_tail_idx
)
847 static void *find_next_entry_inc(struct trace_iterator
*iter
)
849 struct trace_entry
*next
;
852 next
= find_next_entry(iter
, &next_cpu
);
854 iter
->prev_ent
= iter
->ent
;
855 iter
->prev_cpu
= iter
->cpu
;
858 iter
->cpu
= next_cpu
;
861 trace_iterator_increment(iter
);
863 return next
? iter
: NULL
;
866 static void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
868 struct trace_iterator
*iter
= m
->private;
869 void *last_ent
= iter
->ent
;
875 /* can't go backwards */
880 ent
= find_next_entry_inc(iter
);
884 while (ent
&& iter
->idx
< i
)
885 ent
= find_next_entry_inc(iter
);
889 if (last_ent
&& !ent
)
890 seq_puts(m
, "\n\nvim:ft=help\n");
895 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
897 struct trace_iterator
*iter
= m
->private;
902 mutex_lock(&trace_types_lock
);
904 if (!current_trace
|| current_trace
!= iter
->trace
)
907 atomic_inc(&trace_record_cmdline_disabled
);
909 /* let the tracer grab locks here if needed */
910 if (current_trace
->start
)
911 current_trace
->start(iter
);
913 if (*pos
!= iter
->pos
) {
917 iter
->prev_ent
= NULL
;
920 for_each_possible_cpu(i
) {
921 iter
->next_idx
[i
] = 0;
922 iter
->next_page
[i
] = NULL
;
925 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
930 p
= s_next(m
, p
, &l
);
936 static void s_stop(struct seq_file
*m
, void *p
)
938 struct trace_iterator
*iter
= m
->private;
940 atomic_dec(&trace_record_cmdline_disabled
);
942 /* let the tracer release locks here if needed */
943 if (current_trace
&& current_trace
== iter
->trace
&& iter
->trace
->stop
)
944 iter
->trace
->stop(iter
);
946 mutex_unlock(&trace_types_lock
);
950 seq_print_sym_short(struct trace_seq
*s
, const char *fmt
, unsigned long address
)
952 #ifdef CONFIG_KALLSYMS
953 char str
[KSYM_SYMBOL_LEN
];
955 kallsyms_lookup(address
, NULL
, NULL
, NULL
, str
);
957 return trace_seq_printf(s
, fmt
, str
);
963 seq_print_sym_offset(struct trace_seq
*s
, const char *fmt
,
964 unsigned long address
)
966 #ifdef CONFIG_KALLSYMS
967 char str
[KSYM_SYMBOL_LEN
];
969 sprint_symbol(str
, address
);
970 return trace_seq_printf(s
, fmt
, str
);
976 # define IP_FMT "%08lx"
978 # define IP_FMT "%016lx"
982 seq_print_ip_sym(struct trace_seq
*s
, unsigned long ip
, unsigned long sym_flags
)
987 return trace_seq_printf(s
, "0");
989 if (sym_flags
& TRACE_ITER_SYM_OFFSET
)
990 ret
= seq_print_sym_offset(s
, "%s", ip
);
992 ret
= seq_print_sym_short(s
, "%s", ip
);
997 if (sym_flags
& TRACE_ITER_SYM_ADDR
)
998 ret
= trace_seq_printf(s
, " <" IP_FMT
">", ip
);
1002 static void print_lat_help_header(struct seq_file
*m
)
1004 seq_puts(m
, "# _------=> CPU# \n");
1005 seq_puts(m
, "# / _-----=> irqs-off \n");
1006 seq_puts(m
, "# | / _----=> need-resched \n");
1007 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
1008 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
1009 seq_puts(m
, "# |||| / \n");
1010 seq_puts(m
, "# ||||| delay \n");
1011 seq_puts(m
, "# cmd pid ||||| time | caller \n");
1012 seq_puts(m
, "# \\ / ||||| \\ | / \n");
1015 static void print_func_help_header(struct seq_file
*m
)
1017 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1018 seq_puts(m
, "# | | | | |\n");
1023 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
1025 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1026 struct trace_array
*tr
= iter
->tr
;
1027 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
1028 struct tracer
*type
= current_trace
;
1029 unsigned long total
= 0;
1030 unsigned long entries
= 0;
1032 const char *name
= "preemption";
1037 for_each_possible_cpu(cpu
) {
1038 if (head_page(tr
->data
[cpu
])) {
1039 total
+= tr
->data
[cpu
]->trace_idx
;
1040 if (tr
->data
[cpu
]->trace_idx
> tr
->entries
)
1041 entries
+= tr
->entries
;
1043 entries
+= tr
->data
[cpu
]->trace_idx
;
1047 seq_printf(m
, "%s latency trace v1.1.5 on %s\n",
1049 seq_puts(m
, "-----------------------------------"
1050 "---------------------------------\n");
1051 seq_printf(m
, " latency: %lu us, #%lu/%lu, CPU#%d |"
1052 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1053 nsecs_to_usecs(data
->saved_latency
),
1057 #if defined(CONFIG_PREEMPT_NONE)
1059 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1061 #elif defined(CONFIG_PREEMPT_DESKTOP)
1066 /* These are reserved for later use */
1069 seq_printf(m
, " #P:%d)\n", num_online_cpus());
1073 seq_puts(m
, " -----------------\n");
1074 seq_printf(m
, " | task: %.16s-%d "
1075 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1076 data
->comm
, data
->pid
, data
->uid
, data
->nice
,
1077 data
->policy
, data
->rt_priority
);
1078 seq_puts(m
, " -----------------\n");
1080 if (data
->critical_start
) {
1081 seq_puts(m
, " => started at: ");
1082 seq_print_ip_sym(&iter
->seq
, data
->critical_start
, sym_flags
);
1083 trace_print_seq(m
, &iter
->seq
);
1084 seq_puts(m
, "\n => ended at: ");
1085 seq_print_ip_sym(&iter
->seq
, data
->critical_end
, sym_flags
);
1086 trace_print_seq(m
, &iter
->seq
);
1094 lat_print_generic(struct trace_seq
*s
, struct trace_entry
*entry
, int cpu
)
1096 int hardirq
, softirq
;
1099 comm
= trace_find_cmdline(entry
->pid
);
1101 trace_seq_printf(s
, "%8.8s-%-5d ", comm
, entry
->pid
);
1102 trace_seq_printf(s
, "%d", cpu
);
1103 trace_seq_printf(s
, "%c%c",
1104 (entry
->flags
& TRACE_FLAG_IRQS_OFF
) ? 'd' : '.',
1105 ((entry
->flags
& TRACE_FLAG_NEED_RESCHED
) ? 'N' : '.'));
1107 hardirq
= entry
->flags
& TRACE_FLAG_HARDIRQ
;
1108 softirq
= entry
->flags
& TRACE_FLAG_SOFTIRQ
;
1109 if (hardirq
&& softirq
)
1110 trace_seq_putc(s
, 'H');
1113 trace_seq_putc(s
, 'h');
1116 trace_seq_putc(s
, 's');
1118 trace_seq_putc(s
, '.');
1122 if (entry
->preempt_count
)
1123 trace_seq_printf(s
, "%x", entry
->preempt_count
);
1125 trace_seq_puts(s
, ".");
1128 unsigned long preempt_mark_thresh
= 100;
1131 lat_print_timestamp(struct trace_seq
*s
, unsigned long long abs_usecs
,
1132 unsigned long rel_usecs
)
1134 trace_seq_printf(s
, " %4lldus", abs_usecs
);
1135 if (rel_usecs
> preempt_mark_thresh
)
1136 trace_seq_puts(s
, "!: ");
1137 else if (rel_usecs
> 1)
1138 trace_seq_puts(s
, "+: ");
1140 trace_seq_puts(s
, " : ");
1143 static const char state_to_char
[] = TASK_STATE_TO_CHAR_STR
;
1146 print_lat_fmt(struct trace_iterator
*iter
, unsigned int trace_idx
, int cpu
)
1148 struct trace_seq
*s
= &iter
->seq
;
1149 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1150 struct trace_entry
*next_entry
= find_next_entry(iter
, NULL
);
1151 unsigned long verbose
= (trace_flags
& TRACE_ITER_VERBOSE
);
1152 struct trace_entry
*entry
= iter
->ent
;
1153 unsigned long abs_usecs
;
1154 unsigned long rel_usecs
;
1160 rel_usecs
= ns2usecs(next_entry
->t
- entry
->t
);
1161 abs_usecs
= ns2usecs(entry
->t
- iter
->tr
->time_start
);
1164 comm
= trace_find_cmdline(entry
->pid
);
1165 trace_seq_printf(s
, "%16s %5d %d %d %08x %08x [%08lx]"
1166 " %ld.%03ldms (+%ld.%03ldms): ",
1168 entry
->pid
, cpu
, entry
->flags
,
1169 entry
->preempt_count
, trace_idx
,
1172 abs_usecs
% 1000, rel_usecs
/1000,
1175 lat_print_generic(s
, entry
, cpu
);
1176 lat_print_timestamp(s
, abs_usecs
, rel_usecs
);
1178 switch (entry
->type
) {
1180 seq_print_ip_sym(s
, entry
->fn
.ip
, sym_flags
);
1181 trace_seq_puts(s
, " (");
1182 seq_print_ip_sym(s
, entry
->fn
.parent_ip
, sym_flags
);
1183 trace_seq_puts(s
, ")\n");
1186 S
= entry
->ctx
.prev_state
< sizeof(state_to_char
) ?
1187 state_to_char
[entry
->ctx
.prev_state
] : 'X';
1188 comm
= trace_find_cmdline(entry
->ctx
.next_pid
);
1189 trace_seq_printf(s
, " %d:%d:%c --> %d:%d %s\n",
1190 entry
->ctx
.prev_pid
,
1191 entry
->ctx
.prev_prio
,
1193 entry
->ctx
.next_pid
,
1194 entry
->ctx
.next_prio
,
1198 trace_seq_printf(s
, " %lx %lx %lx\n",
1199 entry
->special
.arg1
,
1200 entry
->special
.arg2
,
1201 entry
->special
.arg3
);
1204 trace_seq_printf(s
, "Unknown type %d\n", entry
->type
);
1209 static int print_trace_fmt(struct trace_iterator
*iter
)
1211 struct trace_seq
*s
= &iter
->seq
;
1212 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1213 struct trace_entry
*entry
;
1214 unsigned long usec_rem
;
1215 unsigned long long t
;
1223 comm
= trace_find_cmdline(iter
->ent
->pid
);
1225 t
= ns2usecs(entry
->t
);
1226 usec_rem
= do_div(t
, 1000000ULL);
1227 secs
= (unsigned long)t
;
1229 ret
= trace_seq_printf(s
, "%16s-%-5d ", comm
, entry
->pid
);
1232 ret
= trace_seq_printf(s
, "[%02d] ", iter
->cpu
);
1235 ret
= trace_seq_printf(s
, "%5lu.%06lu: ", secs
, usec_rem
);
1239 switch (entry
->type
) {
1241 ret
= seq_print_ip_sym(s
, entry
->fn
.ip
, sym_flags
);
1244 if ((sym_flags
& TRACE_ITER_PRINT_PARENT
) &&
1245 entry
->fn
.parent_ip
) {
1246 ret
= trace_seq_printf(s
, " <-");
1249 ret
= seq_print_ip_sym(s
, entry
->fn
.parent_ip
,
1254 ret
= trace_seq_printf(s
, "\n");
1259 S
= entry
->ctx
.prev_state
< sizeof(state_to_char
) ?
1260 state_to_char
[entry
->ctx
.prev_state
] : 'X';
1261 ret
= trace_seq_printf(s
, " %d:%d:%c ==> %d:%d\n",
1262 entry
->ctx
.prev_pid
,
1263 entry
->ctx
.prev_prio
,
1265 entry
->ctx
.next_pid
,
1266 entry
->ctx
.next_prio
);
1271 ret
= trace_seq_printf(s
, " %lx %lx %lx\n",
1272 entry
->special
.arg1
,
1273 entry
->special
.arg2
,
1274 entry
->special
.arg3
);
1282 static int print_raw_fmt(struct trace_iterator
*iter
)
1284 struct trace_seq
*s
= &iter
->seq
;
1285 struct trace_entry
*entry
;
1291 ret
= trace_seq_printf(s
, "%d %d %llu ",
1292 entry
->pid
, iter
->cpu
, entry
->t
);
1296 switch (entry
->type
) {
1298 ret
= trace_seq_printf(s
, "%x %x\n",
1299 entry
->fn
.ip
, entry
->fn
.parent_ip
);
1304 S
= entry
->ctx
.prev_state
< sizeof(state_to_char
) ?
1305 state_to_char
[entry
->ctx
.prev_state
] : 'X';
1306 ret
= trace_seq_printf(s
, "%d %d %c %d %d\n",
1307 entry
->ctx
.prev_pid
,
1308 entry
->ctx
.prev_prio
,
1310 entry
->ctx
.next_pid
,
1311 entry
->ctx
.next_prio
);
1316 ret
= trace_seq_printf(s
, " %lx %lx %lx\n",
1317 entry
->special
.arg1
,
1318 entry
->special
.arg2
,
1319 entry
->special
.arg3
);
1327 #define SEQ_PUT_FIELD_RET(s, x) \
1329 if (!trace_seq_putmem(s, &(x), sizeof(x))) \
1333 #define SEQ_PUT_HEX_FIELD_RET(s, x) \
1335 if (!trace_seq_putmem_hex(s, &(x), sizeof(x))) \
1339 static int print_hex_fmt(struct trace_iterator
*iter
)
1341 struct trace_seq
*s
= &iter
->seq
;
1342 unsigned char newline
= '\n';
1343 struct trace_entry
*entry
;
1348 SEQ_PUT_HEX_FIELD_RET(s
, entry
->pid
);
1349 SEQ_PUT_HEX_FIELD_RET(s
, iter
->cpu
);
1350 SEQ_PUT_HEX_FIELD_RET(s
, entry
->t
);
1352 switch (entry
->type
) {
1354 SEQ_PUT_HEX_FIELD_RET(s
, entry
->fn
.ip
);
1355 SEQ_PUT_HEX_FIELD_RET(s
, entry
->fn
.parent_ip
);
1358 S
= entry
->ctx
.prev_state
< sizeof(state_to_char
) ?
1359 state_to_char
[entry
->ctx
.prev_state
] : 'X';
1360 SEQ_PUT_HEX_FIELD_RET(s
, entry
->ctx
.prev_pid
);
1361 SEQ_PUT_HEX_FIELD_RET(s
, entry
->ctx
.prev_prio
);
1362 SEQ_PUT_HEX_FIELD_RET(s
, S
);
1363 SEQ_PUT_HEX_FIELD_RET(s
, entry
->ctx
.next_pid
);
1364 SEQ_PUT_HEX_FIELD_RET(s
, entry
->ctx
.next_prio
);
1365 SEQ_PUT_HEX_FIELD_RET(s
, entry
->fn
.parent_ip
);
1368 SEQ_PUT_HEX_FIELD_RET(s
, entry
->special
.arg1
);
1369 SEQ_PUT_HEX_FIELD_RET(s
, entry
->special
.arg2
);
1370 SEQ_PUT_HEX_FIELD_RET(s
, entry
->special
.arg3
);
1373 SEQ_PUT_FIELD_RET(s
, newline
);
1378 static int print_bin_fmt(struct trace_iterator
*iter
)
1380 struct trace_seq
*s
= &iter
->seq
;
1381 struct trace_entry
*entry
;
1385 SEQ_PUT_FIELD_RET(s
, entry
->pid
);
1386 SEQ_PUT_FIELD_RET(s
, entry
->cpu
);
1387 SEQ_PUT_FIELD_RET(s
, entry
->t
);
1389 switch (entry
->type
) {
1391 SEQ_PUT_FIELD_RET(s
, entry
->fn
.ip
);
1392 SEQ_PUT_FIELD_RET(s
, entry
->fn
.parent_ip
);
1395 SEQ_PUT_FIELD_RET(s
, entry
->ctx
.prev_pid
);
1396 SEQ_PUT_FIELD_RET(s
, entry
->ctx
.prev_prio
);
1397 SEQ_PUT_FIELD_RET(s
, entry
->ctx
.prev_state
);
1398 SEQ_PUT_FIELD_RET(s
, entry
->ctx
.next_pid
);
1399 SEQ_PUT_FIELD_RET(s
, entry
->ctx
.next_prio
);
1402 SEQ_PUT_FIELD_RET(s
, entry
->special
.arg1
);
1403 SEQ_PUT_FIELD_RET(s
, entry
->special
.arg2
);
1404 SEQ_PUT_FIELD_RET(s
, entry
->special
.arg3
);
1410 static int trace_empty(struct trace_iterator
*iter
)
1412 struct trace_array_cpu
*data
;
1415 for_each_possible_cpu(cpu
) {
1416 data
= iter
->tr
->data
[cpu
];
1418 if (head_page(data
) && data
->trace_idx
&&
1419 (data
->trace_tail
!= data
->trace_head
||
1420 data
->trace_tail_idx
!= data
->trace_head_idx
))
1426 static int print_trace_line(struct trace_iterator
*iter
)
1428 if (trace_flags
& TRACE_ITER_BIN
)
1429 return print_bin_fmt(iter
);
1431 if (trace_flags
& TRACE_ITER_HEX
)
1432 return print_hex_fmt(iter
);
1434 if (trace_flags
& TRACE_ITER_RAW
)
1435 return print_raw_fmt(iter
);
1437 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
)
1438 return print_lat_fmt(iter
, iter
->idx
, iter
->cpu
);
1440 return print_trace_fmt(iter
);
1443 static int s_show(struct seq_file
*m
, void *v
)
1445 struct trace_iterator
*iter
= v
;
1447 if (iter
->ent
== NULL
) {
1449 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
1452 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1453 /* print nothing if the buffers are empty */
1454 if (trace_empty(iter
))
1456 print_trace_header(m
, iter
);
1457 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1458 print_lat_help_header(m
);
1460 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1461 print_func_help_header(m
);
1464 print_trace_line(iter
);
1465 trace_print_seq(m
, &iter
->seq
);
1471 static struct seq_operations tracer_seq_ops
= {
1478 static struct trace_iterator
*
1479 __tracing_open(struct inode
*inode
, struct file
*file
, int *ret
)
1481 struct trace_iterator
*iter
;
1483 if (tracing_disabled
) {
1488 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
1494 mutex_lock(&trace_types_lock
);
1495 if (current_trace
&& current_trace
->print_max
)
1498 iter
->tr
= inode
->i_private
;
1499 iter
->trace
= current_trace
;
1502 /* TODO stop tracer */
1503 *ret
= seq_open(file
, &tracer_seq_ops
);
1505 struct seq_file
*m
= file
->private_data
;
1508 /* stop the trace while dumping */
1512 if (iter
->trace
&& iter
->trace
->open
)
1513 iter
->trace
->open(iter
);
1518 mutex_unlock(&trace_types_lock
);
1524 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
1526 if (tracing_disabled
)
1529 filp
->private_data
= inode
->i_private
;
1533 int tracing_release(struct inode
*inode
, struct file
*file
)
1535 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
1536 struct trace_iterator
*iter
= m
->private;
1538 mutex_lock(&trace_types_lock
);
1539 if (iter
->trace
&& iter
->trace
->close
)
1540 iter
->trace
->close(iter
);
1542 /* reenable tracing if it was previously enabled */
1545 mutex_unlock(&trace_types_lock
);
1547 seq_release(inode
, file
);
1552 static int tracing_open(struct inode
*inode
, struct file
*file
)
1556 __tracing_open(inode
, file
, &ret
);
1561 static int tracing_lt_open(struct inode
*inode
, struct file
*file
)
1563 struct trace_iterator
*iter
;
1566 iter
= __tracing_open(inode
, file
, &ret
);
1569 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
1576 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1578 struct tracer
*t
= m
->private;
1590 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
1592 struct tracer
*t
= m
->private;
1595 mutex_lock(&trace_types_lock
);
1596 for (; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
1602 static void t_stop(struct seq_file
*m
, void *p
)
1604 mutex_unlock(&trace_types_lock
);
1607 static int t_show(struct seq_file
*m
, void *v
)
1609 struct tracer
*t
= v
;
1614 seq_printf(m
, "%s", t
->name
);
1623 static struct seq_operations show_traces_seq_ops
= {
1630 static int show_traces_open(struct inode
*inode
, struct file
*file
)
1634 if (tracing_disabled
)
1637 ret
= seq_open(file
, &show_traces_seq_ops
);
1639 struct seq_file
*m
= file
->private_data
;
1640 m
->private = trace_types
;
1646 static struct file_operations tracing_fops
= {
1647 .open
= tracing_open
,
1649 .llseek
= seq_lseek
,
1650 .release
= tracing_release
,
1653 static struct file_operations tracing_lt_fops
= {
1654 .open
= tracing_lt_open
,
1656 .llseek
= seq_lseek
,
1657 .release
= tracing_release
,
1660 static struct file_operations show_traces_fops
= {
1661 .open
= show_traces_open
,
1663 .release
= seq_release
,
1667 tracing_iter_ctrl_read(struct file
*filp
, char __user
*ubuf
,
1668 size_t cnt
, loff_t
*ppos
)
1675 /* calulate max size */
1676 for (i
= 0; trace_options
[i
]; i
++) {
1677 len
+= strlen(trace_options
[i
]);
1678 len
+= 3; /* "no" and space */
1681 /* +2 for \n and \0 */
1682 buf
= kmalloc(len
+ 2, GFP_KERNEL
);
1686 for (i
= 0; trace_options
[i
]; i
++) {
1687 if (trace_flags
& (1 << i
))
1688 r
+= sprintf(buf
+ r
, "%s ", trace_options
[i
]);
1690 r
+= sprintf(buf
+ r
, "no%s ", trace_options
[i
]);
1693 r
+= sprintf(buf
+ r
, "\n");
1694 WARN_ON(r
>= len
+ 2);
1696 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
1705 tracing_iter_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
1706 size_t cnt
, loff_t
*ppos
)
1716 if (copy_from_user(&buf
, ubuf
, cnt
))
1721 if (strncmp(buf
, "no", 2) == 0) {
1726 for (i
= 0; trace_options
[i
]; i
++) {
1727 int len
= strlen(trace_options
[i
]);
1729 if (strncmp(cmp
, trace_options
[i
], len
) == 0) {
1731 trace_flags
&= ~(1 << i
);
1733 trace_flags
|= (1 << i
);
1743 static struct file_operations tracing_iter_fops
= {
1744 .open
= tracing_open_generic
,
1745 .read
= tracing_iter_ctrl_read
,
1746 .write
= tracing_iter_ctrl_write
,
1749 static const char readme_msg
[] =
1750 "tracing mini-HOWTO:\n\n"
1752 "# mount -t debugfs nodev /debug\n\n"
1753 "# cat /debug/tracing/available_tracers\n"
1754 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
1755 "# cat /debug/tracing/current_tracer\n"
1757 "# echo sched_switch > /debug/tracing/current_tracer\n"
1758 "# cat /debug/tracing/current_tracer\n"
1760 "# cat /debug/tracing/iter_ctrl\n"
1761 "noprint-parent nosym-offset nosym-addr noverbose\n"
1762 "# echo print-parent > /debug/tracing/iter_ctrl\n"
1763 "# echo 1 > /debug/tracing/tracing_enabled\n"
1764 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
1765 "echo 0 > /debug/tracing/tracing_enabled\n"
1769 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
1770 size_t cnt
, loff_t
*ppos
)
1772 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
1773 readme_msg
, strlen(readme_msg
));
1776 static struct file_operations tracing_readme_fops
= {
1777 .open
= tracing_open_generic
,
1778 .read
= tracing_readme_read
,
1782 tracing_ctrl_read(struct file
*filp
, char __user
*ubuf
,
1783 size_t cnt
, loff_t
*ppos
)
1785 struct trace_array
*tr
= filp
->private_data
;
1789 r
= sprintf(buf
, "%ld\n", tr
->ctrl
);
1790 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
1794 tracing_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
1795 size_t cnt
, loff_t
*ppos
)
1797 struct trace_array
*tr
= filp
->private_data
;
1804 if (copy_from_user(&buf
, ubuf
, cnt
))
1809 val
= simple_strtoul(buf
, NULL
, 10);
1813 mutex_lock(&trace_types_lock
);
1814 if (tr
->ctrl
^ val
) {
1822 if (current_trace
&& current_trace
->ctrl_update
)
1823 current_trace
->ctrl_update(tr
);
1825 mutex_unlock(&trace_types_lock
);
1833 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
1834 size_t cnt
, loff_t
*ppos
)
1836 char buf
[max_tracer_type_len
+2];
1839 mutex_lock(&trace_types_lock
);
1841 r
= sprintf(buf
, "%s\n", current_trace
->name
);
1843 r
= sprintf(buf
, "\n");
1844 mutex_unlock(&trace_types_lock
);
1846 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
1850 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
1851 size_t cnt
, loff_t
*ppos
)
1853 struct trace_array
*tr
= &global_trace
;
1855 char buf
[max_tracer_type_len
+1];
1858 if (cnt
> max_tracer_type_len
)
1859 cnt
= max_tracer_type_len
;
1861 if (copy_from_user(&buf
, ubuf
, cnt
))
1866 /* strip ending whitespace. */
1867 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
1870 mutex_lock(&trace_types_lock
);
1871 for (t
= trace_types
; t
; t
= t
->next
) {
1872 if (strcmp(t
->name
, buf
) == 0)
1875 if (!t
|| t
== current_trace
)
1878 if (current_trace
&& current_trace
->reset
)
1879 current_trace
->reset(tr
);
1886 mutex_unlock(&trace_types_lock
);
1894 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
1895 size_t cnt
, loff_t
*ppos
)
1897 unsigned long *ptr
= filp
->private_data
;
1901 r
= snprintf(buf
, 64, "%ld\n",
1902 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
1905 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
1909 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
1910 size_t cnt
, loff_t
*ppos
)
1912 long *ptr
= filp
->private_data
;
1919 if (copy_from_user(&buf
, ubuf
, cnt
))
1924 val
= simple_strtoul(buf
, NULL
, 10);
1931 static atomic_t tracing_reader
;
1933 static int tracing_open_pipe(struct inode
*inode
, struct file
*filp
)
1935 struct trace_iterator
*iter
;
1937 if (tracing_disabled
)
1940 /* We only allow for reader of the pipe */
1941 if (atomic_inc_return(&tracing_reader
) != 1) {
1942 atomic_dec(&tracing_reader
);
1946 /* create a buffer to store the information to pass to userspace */
1947 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
1951 iter
->tr
= &global_trace
;
1953 filp
->private_data
= iter
;
1958 static int tracing_release_pipe(struct inode
*inode
, struct file
*file
)
1960 struct trace_iterator
*iter
= file
->private_data
;
1963 atomic_dec(&tracing_reader
);
1969 tracing_poll_pipe(struct file
*filp
, poll_table
*poll_table
)
1971 struct trace_iterator
*iter
= filp
->private_data
;
1973 if (trace_flags
& TRACE_ITER_BLOCK
) {
1975 * Always select as readable when in blocking mode
1977 return POLLIN
| POLLRDNORM
;
1980 if (!trace_empty(iter
))
1981 return POLLIN
| POLLRDNORM
;
1982 poll_wait(filp
, &trace_wait
, poll_table
);
1983 if (!trace_empty(iter
))
1984 return POLLIN
| POLLRDNORM
;
1994 tracing_read_pipe(struct file
*filp
, char __user
*ubuf
,
1995 size_t cnt
, loff_t
*ppos
)
1997 struct trace_iterator
*iter
= filp
->private_data
;
1998 struct trace_array_cpu
*data
;
1999 static cpumask_t mask
;
2001 unsigned long flags
;
2002 #ifdef CONFIG_FTRACE
2010 /* return any leftover data */
2011 if (iter
->seq
.len
> start
) {
2012 len
= iter
->seq
.len
- start
;
2015 ret
= copy_to_user(ubuf
, iter
->seq
.buffer
+ start
, cnt
);
2024 trace_seq_reset(&iter
->seq
);
2027 while (trace_empty(iter
)) {
2028 if (!(trace_flags
& TRACE_ITER_BLOCK
))
2029 return -EWOULDBLOCK
;
2031 * This is a make-shift waitqueue. The reason we don't use
2032 * an actual wait queue is because:
2033 * 1) we only ever have one waiter
2034 * 2) the tracing, traces all functions, we don't want
2035 * the overhead of calling wake_up and friends
2036 * (and tracing them too)
2037 * Anyway, this is really very primitive wakeup.
2039 set_current_state(TASK_INTERRUPTIBLE
);
2040 iter
->tr
->waiter
= current
;
2042 /* sleep for one second, and try again. */
2043 schedule_timeout(HZ
);
2045 iter
->tr
->waiter
= NULL
;
2047 if (signal_pending(current
))
2051 * We block until we read something and tracing is disabled.
2052 * We still block if tracing is disabled, but we have never
2053 * read anything. This allows a user to cat this file, and
2054 * then enable tracing. But after we have read something,
2055 * we give an EOF when tracing is again disabled.
2057 * iter->pos will be 0 if we haven't read anything.
2059 if (!tracer_enabled
&& iter
->pos
)
2065 /* stop when tracing is finished */
2066 if (trace_empty(iter
))
2069 if (cnt
>= PAGE_SIZE
)
2070 cnt
= PAGE_SIZE
- 1;
2072 memset(iter
, 0, sizeof(*iter
));
2073 iter
->tr
= &global_trace
;
2077 * We need to stop all tracing on all CPUS to read the
2078 * the next buffer. This is a bit expensive, but is
2079 * not done often. We fill all what we can read,
2080 * and then release the locks again.
2084 local_irq_save(flags
);
2085 #ifdef CONFIG_FTRACE
2086 ftrace_save
= ftrace_enabled
;
2090 for_each_possible_cpu(cpu
) {
2091 data
= iter
->tr
->data
[cpu
];
2093 if (!head_page(data
) || !data
->trace_idx
)
2096 atomic_inc(&data
->disabled
);
2100 for_each_cpu_mask(cpu
, mask
) {
2101 data
= iter
->tr
->data
[cpu
];
2102 spin_lock(&data
->lock
);
2105 while (find_next_entry_inc(iter
) != NULL
) {
2106 int len
= iter
->seq
.len
;
2108 ret
= print_trace_line(iter
);
2110 /* don't print partial lines */
2111 iter
->seq
.len
= len
;
2115 trace_consume(iter
);
2117 if (iter
->seq
.len
>= cnt
)
2121 for_each_cpu_mask(cpu
, mask
) {
2122 data
= iter
->tr
->data
[cpu
];
2123 spin_unlock(&data
->lock
);
2126 for_each_cpu_mask(cpu
, mask
) {
2127 data
= iter
->tr
->data
[cpu
];
2128 atomic_dec(&data
->disabled
);
2130 #ifdef CONFIG_FTRACE
2131 ftrace_enabled
= ftrace_save
;
2133 local_irq_restore(flags
);
2135 /* Now copy what we have to the user */
2136 read
= iter
->seq
.len
;
2140 ret
= copy_to_user(ubuf
, iter
->seq
.buffer
, read
);
2142 if (read
< iter
->seq
.len
)
2145 trace_seq_reset(&iter
->seq
);
2153 static struct file_operations tracing_max_lat_fops
= {
2154 .open
= tracing_open_generic
,
2155 .read
= tracing_max_lat_read
,
2156 .write
= tracing_max_lat_write
,
2159 static struct file_operations tracing_ctrl_fops
= {
2160 .open
= tracing_open_generic
,
2161 .read
= tracing_ctrl_read
,
2162 .write
= tracing_ctrl_write
,
2165 static struct file_operations set_tracer_fops
= {
2166 .open
= tracing_open_generic
,
2167 .read
= tracing_set_trace_read
,
2168 .write
= tracing_set_trace_write
,
2171 static struct file_operations tracing_pipe_fops
= {
2172 .open
= tracing_open_pipe
,
2173 .poll
= tracing_poll_pipe
,
2174 .read
= tracing_read_pipe
,
2175 .release
= tracing_release_pipe
,
2178 #ifdef CONFIG_DYNAMIC_FTRACE
2181 tracing_read_long(struct file
*filp
, char __user
*ubuf
,
2182 size_t cnt
, loff_t
*ppos
)
2184 unsigned long *p
= filp
->private_data
;
2188 r
= sprintf(buf
, "%ld\n", *p
);
2190 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
2193 static struct file_operations tracing_read_long_fops
= {
2194 .open
= tracing_open_generic
,
2195 .read
= tracing_read_long
,
2199 static struct dentry
*d_tracer
;
2201 struct dentry
*tracing_init_dentry(void)
2208 d_tracer
= debugfs_create_dir("tracing", NULL
);
2210 if (!d_tracer
&& !once
) {
2212 pr_warning("Could not create debugfs directory 'tracing'\n");
2219 #ifdef CONFIG_FTRACE_SELFTEST
2220 /* Let selftest have access to static functions in this file */
2221 #include "trace_selftest.c"
2224 static __init
void tracer_init_debugfs(void)
2226 struct dentry
*d_tracer
;
2227 struct dentry
*entry
;
2229 d_tracer
= tracing_init_dentry();
2231 entry
= debugfs_create_file("tracing_enabled", 0644, d_tracer
,
2232 &global_trace
, &tracing_ctrl_fops
);
2234 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
2236 entry
= debugfs_create_file("iter_ctrl", 0644, d_tracer
,
2237 NULL
, &tracing_iter_fops
);
2239 pr_warning("Could not create debugfs 'iter_ctrl' entry\n");
2241 entry
= debugfs_create_file("latency_trace", 0444, d_tracer
,
2242 &global_trace
, &tracing_lt_fops
);
2244 pr_warning("Could not create debugfs 'latency_trace' entry\n");
2246 entry
= debugfs_create_file("trace", 0444, d_tracer
,
2247 &global_trace
, &tracing_fops
);
2249 pr_warning("Could not create debugfs 'trace' entry\n");
2251 entry
= debugfs_create_file("available_tracers", 0444, d_tracer
,
2252 &global_trace
, &show_traces_fops
);
2254 pr_warning("Could not create debugfs 'trace' entry\n");
2256 entry
= debugfs_create_file("current_tracer", 0444, d_tracer
,
2257 &global_trace
, &set_tracer_fops
);
2259 pr_warning("Could not create debugfs 'trace' entry\n");
2261 entry
= debugfs_create_file("tracing_max_latency", 0644, d_tracer
,
2262 &tracing_max_latency
,
2263 &tracing_max_lat_fops
);
2265 pr_warning("Could not create debugfs "
2266 "'tracing_max_latency' entry\n");
2268 entry
= debugfs_create_file("tracing_thresh", 0644, d_tracer
,
2269 &tracing_thresh
, &tracing_max_lat_fops
);
2271 pr_warning("Could not create debugfs "
2272 "'tracing_threash' entry\n");
2273 entry
= debugfs_create_file("README", 0644, d_tracer
,
2274 NULL
, &tracing_readme_fops
);
2276 pr_warning("Could not create debugfs 'README' entry\n");
2278 entry
= debugfs_create_file("trace_pipe", 0644, d_tracer
,
2279 NULL
, &tracing_pipe_fops
);
2281 pr_warning("Could not create debugfs "
2282 "'tracing_threash' entry\n");
2284 #ifdef CONFIG_DYNAMIC_FTRACE
2285 entry
= debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
2286 &ftrace_update_tot_cnt
,
2287 &tracing_read_long_fops
);
2289 pr_warning("Could not create debugfs "
2290 "'dyn_ftrace_total_info' entry\n");
2294 /* dummy trace to disable tracing */
2295 static struct tracer no_tracer __read_mostly
=
2300 static int trace_alloc_page(void)
2302 struct trace_array_cpu
*data
;
2303 struct page
*page
, *tmp
;
2308 /* first allocate a page for each CPU */
2309 for_each_possible_cpu(i
) {
2310 array
= (void *)__get_free_page(GFP_KERNEL
);
2311 if (array
== NULL
) {
2312 printk(KERN_ERR
"tracer: failed to allocate page"
2313 "for trace buffer!\n");
2317 page
= virt_to_page(array
);
2318 list_add(&page
->lru
, &pages
);
2320 /* Only allocate if we are actually using the max trace */
2321 #ifdef CONFIG_TRACER_MAX_TRACE
2322 array
= (void *)__get_free_page(GFP_KERNEL
);
2323 if (array
== NULL
) {
2324 printk(KERN_ERR
"tracer: failed to allocate page"
2325 "for trace buffer!\n");
2328 page
= virt_to_page(array
);
2329 list_add(&page
->lru
, &pages
);
2333 /* Now that we successfully allocate a page per CPU, add them */
2334 for_each_possible_cpu(i
) {
2335 data
= global_trace
.data
[i
];
2336 spin_lock_init(&data
->lock
);
2337 lockdep_set_class(&data
->lock
, &data
->lock_key
);
2338 page
= list_entry(pages
.next
, struct page
, lru
);
2339 list_del_init(&page
->lru
);
2340 list_add_tail(&page
->lru
, &data
->trace_pages
);
2343 #ifdef CONFIG_TRACER_MAX_TRACE
2344 data
= max_tr
.data
[i
];
2345 spin_lock_init(&data
->lock
);
2346 lockdep_set_class(&data
->lock
, &data
->lock_key
);
2347 page
= list_entry(pages
.next
, struct page
, lru
);
2348 list_del_init(&page
->lru
);
2349 list_add_tail(&page
->lru
, &data
->trace_pages
);
2353 global_trace
.entries
+= ENTRIES_PER_PAGE
;
2358 list_for_each_entry_safe(page
, tmp
, &pages
, lru
) {
2359 list_del_init(&page
->lru
);
2365 __init
static int tracer_alloc_buffers(void)
2367 struct trace_array_cpu
*data
;
2374 global_trace
.ctrl
= tracer_enabled
;
2376 /* Allocate the first page for all buffers */
2377 for_each_possible_cpu(i
) {
2378 data
= global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
2379 max_tr
.data
[i
] = &per_cpu(max_data
, i
);
2381 array
= (void *)__get_free_page(GFP_KERNEL
);
2382 if (array
== NULL
) {
2383 printk(KERN_ERR
"tracer: failed to allocate page"
2384 "for trace buffer!\n");
2388 /* set the array to the list */
2389 INIT_LIST_HEAD(&data
->trace_pages
);
2390 page
= virt_to_page(array
);
2391 list_add(&page
->lru
, &data
->trace_pages
);
2392 /* use the LRU flag to differentiate the two buffers */
2395 /* Only allocate if we are actually using the max trace */
2396 #ifdef CONFIG_TRACER_MAX_TRACE
2397 array
= (void *)__get_free_page(GFP_KERNEL
);
2398 if (array
== NULL
) {
2399 printk(KERN_ERR
"tracer: failed to allocate page"
2400 "for trace buffer!\n");
2404 INIT_LIST_HEAD(&max_tr
.data
[i
]->trace_pages
);
2405 page
= virt_to_page(array
);
2406 list_add(&page
->lru
, &max_tr
.data
[i
]->trace_pages
);
2412 * Since we allocate by orders of pages, we may be able to
2415 global_trace
.entries
= ENTRIES_PER_PAGE
;
2418 while (global_trace
.entries
< trace_nr_entries
) {
2419 if (trace_alloc_page())
2423 max_tr
.entries
= global_trace
.entries
;
2425 pr_info("tracer: %d pages allocated for %ld",
2426 pages
, trace_nr_entries
);
2427 pr_info(" entries of %ld bytes\n", (long)TRACE_ENTRY_SIZE
);
2428 pr_info(" actual entries %ld\n", global_trace
.entries
);
2430 tracer_init_debugfs();
2432 trace_init_cmdlines();
2434 register_tracer(&no_tracer
);
2435 current_trace
= &no_tracer
;
2437 /* All seems OK, enable tracing */
2438 tracing_disabled
= 0;
2443 for (i
-- ; i
>= 0; i
--) {
2444 struct page
*page
, *tmp
;
2445 struct trace_array_cpu
*data
= global_trace
.data
[i
];
2448 list_for_each_entry_safe(page
, tmp
,
2449 &data
->trace_pages
, lru
) {
2450 list_del_init(&page
->lru
);
2455 #ifdef CONFIG_TRACER_MAX_TRACE
2456 data
= max_tr
.data
[i
];
2458 list_for_each_entry_safe(page
, tmp
,
2459 &data
->trace_pages
, lru
) {
2460 list_del_init(&page
->lru
);
2468 fs_initcall(tracer_alloc_buffers
);