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 flip_trace(struct trace_array_cpu
*tr1
, struct trace_array_cpu
*tr2
)
175 struct list_head flip_pages
;
177 INIT_LIST_HEAD(&flip_pages
);
179 tr1
->trace_current
= NULL
;
180 memcpy(&tr1
->trace_current_idx
, &tr2
->trace_current_idx
,
181 sizeof(struct trace_array_cpu
) -
182 offsetof(struct trace_array_cpu
, trace_current_idx
));
186 list_splice_init(&tr1
->trace_pages
, &flip_pages
);
187 list_splice_init(&tr2
->trace_pages
, &tr1
->trace_pages
);
188 list_splice_init(&flip_pages
, &tr2
->trace_pages
);
189 BUG_ON(!list_empty(&flip_pages
));
195 update_max_tr(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
197 struct trace_array_cpu
*data
;
200 WARN_ON_ONCE(!irqs_disabled());
201 spin_lock(&ftrace_max_lock
);
202 /* clear out all the previous traces */
203 for_each_possible_cpu(i
) {
205 flip_trace(max_tr
.data
[i
], data
);
209 __update_max_tr(tr
, tsk
, cpu
);
210 spin_unlock(&ftrace_max_lock
);
214 * update_max_tr_single - only copy one trace over, and reset the rest
216 * @tsk - task with the latency
217 * @cpu - the cpu of the buffer to copy.
220 update_max_tr_single(struct trace_array
*tr
, struct task_struct
*tsk
, int cpu
)
222 struct trace_array_cpu
*data
= tr
->data
[cpu
];
225 WARN_ON_ONCE(!irqs_disabled());
226 spin_lock(&ftrace_max_lock
);
227 for_each_possible_cpu(i
)
228 tracing_reset(max_tr
.data
[i
]);
230 flip_trace(max_tr
.data
[cpu
], data
);
234 __update_max_tr(tr
, tsk
, cpu
);
235 spin_unlock(&ftrace_max_lock
);
238 int register_tracer(struct tracer
*type
)
245 pr_info("Tracer must have a name\n");
249 mutex_lock(&trace_types_lock
);
250 for (t
= trace_types
; t
; t
= t
->next
) {
251 if (strcmp(type
->name
, t
->name
) == 0) {
253 pr_info("Trace %s already registered\n",
260 #ifdef CONFIG_FTRACE_STARTUP_TEST
261 if (type
->selftest
) {
262 struct tracer
*saved_tracer
= current_trace
;
263 struct trace_array_cpu
*data
;
264 struct trace_array
*tr
= &global_trace
;
265 int saved_ctrl
= tr
->ctrl
;
268 * Run a selftest on this tracer.
269 * Here we reset the trace buffer, and set the current
270 * tracer to be this tracer. The tracer can then run some
271 * internal tracing to verify that everything is in order.
272 * If we fail, we do not register this tracer.
274 for_each_possible_cpu(i
) {
276 if (!head_page(data
))
280 current_trace
= type
;
282 /* the test is responsible for initializing and enabling */
283 pr_info("Testing tracer %s: ", type
->name
);
284 ret
= type
->selftest(type
, tr
);
285 /* the test is responsible for resetting too */
286 current_trace
= saved_tracer
;
287 tr
->ctrl
= saved_ctrl
;
289 printk(KERN_CONT
"FAILED!\n");
292 printk(KERN_CONT
"PASSED\n");
296 type
->next
= trace_types
;
298 len
= strlen(type
->name
);
299 if (len
> max_tracer_type_len
)
300 max_tracer_type_len
= len
;
303 mutex_unlock(&trace_types_lock
);
308 void unregister_tracer(struct tracer
*type
)
313 mutex_lock(&trace_types_lock
);
314 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
318 pr_info("Trace %s not registered\n", type
->name
);
323 if (strlen(type
->name
) != max_tracer_type_len
)
326 max_tracer_type_len
= 0;
327 for (t
= &trace_types
; *t
; t
= &(*t
)->next
) {
328 len
= strlen((*t
)->name
);
329 if (len
> max_tracer_type_len
)
330 max_tracer_type_len
= len
;
333 mutex_unlock(&trace_types_lock
);
336 notrace
void tracing_reset(struct trace_array_cpu
*data
)
339 data
->trace_current
= head_page(data
);
340 data
->trace_current_idx
= 0;
341 data
->time_offset
= 0;
346 function_trace_call(unsigned long ip
, unsigned long parent_ip
)
348 struct trace_array
*tr
= &global_trace
;
349 struct trace_array_cpu
*data
;
354 if (unlikely(!tracer_enabled
))
357 local_irq_save(flags
);
358 cpu
= raw_smp_processor_id();
359 data
= tr
->data
[cpu
];
360 disabled
= atomic_inc_return(&data
->disabled
);
362 if (likely(disabled
== 1))
363 ftrace(tr
, data
, ip
, parent_ip
, flags
);
365 atomic_dec(&data
->disabled
);
366 local_irq_restore(flags
);
369 static struct ftrace_ops trace_ops __read_mostly
=
371 .func
= function_trace_call
,
375 notrace
void tracing_start_function_trace(void)
377 register_ftrace_function(&trace_ops
);
380 notrace
void tracing_stop_function_trace(void)
382 unregister_ftrace_function(&trace_ops
);
385 #define SAVED_CMDLINES 128
386 static unsigned map_pid_to_cmdline
[PID_MAX_DEFAULT
+1];
387 static unsigned map_cmdline_to_pid
[SAVED_CMDLINES
];
388 static char saved_cmdlines
[SAVED_CMDLINES
][TASK_COMM_LEN
];
389 static int cmdline_idx
;
390 static DEFINE_SPINLOCK(trace_cmdline_lock
);
391 atomic_t trace_record_cmdline_disabled
;
393 static void trace_init_cmdlines(void)
395 memset(&map_pid_to_cmdline
, -1, sizeof(map_pid_to_cmdline
));
396 memset(&map_cmdline_to_pid
, -1, sizeof(map_cmdline_to_pid
));
400 notrace
void trace_stop_cmdline_recording(void);
402 static notrace
void trace_save_cmdline(struct task_struct
*tsk
)
407 if (!tsk
->pid
|| unlikely(tsk
->pid
> PID_MAX_DEFAULT
))
411 * It's not the end of the world if we don't get
412 * the lock, but we also don't want to spin
413 * nor do we want to disable interrupts,
414 * so if we miss here, then better luck next time.
416 if (!spin_trylock(&trace_cmdline_lock
))
419 idx
= map_pid_to_cmdline
[tsk
->pid
];
420 if (idx
>= SAVED_CMDLINES
) {
421 idx
= (cmdline_idx
+ 1) % SAVED_CMDLINES
;
423 map
= map_cmdline_to_pid
[idx
];
424 if (map
<= PID_MAX_DEFAULT
)
425 map_pid_to_cmdline
[map
] = (unsigned)-1;
427 map_pid_to_cmdline
[tsk
->pid
] = idx
;
432 memcpy(&saved_cmdlines
[idx
], tsk
->comm
, TASK_COMM_LEN
);
434 spin_unlock(&trace_cmdline_lock
);
437 static notrace
char *trace_find_cmdline(int pid
)
439 char *cmdline
= "<...>";
445 if (pid
> PID_MAX_DEFAULT
)
448 map
= map_pid_to_cmdline
[pid
];
449 if (map
>= SAVED_CMDLINES
)
452 cmdline
= saved_cmdlines
[map
];
458 notrace
void tracing_record_cmdline(struct task_struct
*tsk
)
460 if (atomic_read(&trace_record_cmdline_disabled
))
463 trace_save_cmdline(tsk
);
466 static inline notrace
struct trace_entry
*
467 tracing_get_trace_entry(struct trace_array
*tr
, struct trace_array_cpu
*data
)
469 unsigned long idx
, idx_next
;
470 struct trace_entry
*entry
;
471 struct list_head
*next
;
475 idx
= data
->trace_current_idx
;
478 BUG_ON(idx
* TRACE_ENTRY_SIZE
>= PAGE_SIZE
);
480 entry
= data
->trace_current
+ idx
* TRACE_ENTRY_SIZE
;
482 if (unlikely(idx_next
>= ENTRIES_PER_PAGE
)) {
483 page
= virt_to_page(data
->trace_current
);
485 * Roundrobin - but skip the head (which is not a real page):
487 next
= page
->lru
.next
;
488 if (unlikely(next
== &data
->trace_pages
))
490 BUG_ON(next
== &data
->trace_pages
);
492 page
= list_entry(next
, struct page
, lru
);
493 data
->trace_current
= page_address(page
);
497 data
->trace_current_idx
= idx_next
;
502 static inline notrace
void
503 tracing_generic_entry_update(struct trace_entry
*entry
, unsigned long flags
)
505 struct task_struct
*tsk
= current
;
508 pc
= preempt_count();
510 entry
->idx
= atomic_inc_return(&tracer_counter
);
511 entry
->preempt_count
= pc
& 0xff;
512 entry
->pid
= tsk
->pid
;
513 entry
->t
= now(raw_smp_processor_id());
514 entry
->flags
= (irqs_disabled_flags(flags
) ? TRACE_FLAG_IRQS_OFF
: 0) |
515 ((pc
& HARDIRQ_MASK
) ? TRACE_FLAG_HARDIRQ
: 0) |
516 ((pc
& SOFTIRQ_MASK
) ? TRACE_FLAG_SOFTIRQ
: 0) |
517 (need_resched() ? TRACE_FLAG_NEED_RESCHED
: 0);
521 ftrace(struct trace_array
*tr
, struct trace_array_cpu
*data
,
522 unsigned long ip
, unsigned long parent_ip
, unsigned long flags
)
524 struct trace_entry
*entry
;
526 entry
= tracing_get_trace_entry(tr
, data
);
527 tracing_generic_entry_update(entry
, flags
);
528 entry
->type
= TRACE_FN
;
530 entry
->fn
.parent_ip
= parent_ip
;
534 tracing_sched_switch_trace(struct trace_array
*tr
,
535 struct trace_array_cpu
*data
,
536 struct task_struct
*prev
, struct task_struct
*next
,
539 struct trace_entry
*entry
;
541 entry
= tracing_get_trace_entry(tr
, data
);
542 tracing_generic_entry_update(entry
, flags
);
543 entry
->type
= TRACE_CTX
;
544 entry
->ctx
.prev_pid
= prev
->pid
;
545 entry
->ctx
.prev_prio
= prev
->prio
;
546 entry
->ctx
.prev_state
= prev
->state
;
547 entry
->ctx
.next_pid
= next
->pid
;
548 entry
->ctx
.next_prio
= next
->prio
;
551 enum trace_file_type
{
552 TRACE_FILE_LAT_FMT
= 1,
555 static struct trace_entry
*
556 trace_entry_idx(struct trace_array
*tr
, struct trace_array_cpu
*data
,
557 struct trace_iterator
*iter
, int cpu
)
560 struct trace_entry
*array
;
562 if (iter
->next_idx
[cpu
] >= tr
->entries
||
563 iter
->next_idx
[cpu
] >= data
->trace_idx
)
566 if (!iter
->next_page
[cpu
]) {
568 * Initialize. If the count of elements in
569 * this buffer is greater than the max entries
570 * we had an underrun. Which means we looped around.
571 * We can simply use the current pointer as our
574 if (data
->trace_idx
>= tr
->entries
) {
575 page
= virt_to_page(data
->trace_current
);
576 iter
->next_page
[cpu
] = &page
->lru
;
577 iter
->next_page_idx
[cpu
] = data
->trace_current_idx
;
579 iter
->next_page
[cpu
] = data
->trace_pages
.next
;
580 iter
->next_page_idx
[cpu
] = 0;
584 page
= list_entry(iter
->next_page
[cpu
], struct page
, lru
);
585 BUG_ON(&data
->trace_pages
== &page
->lru
);
587 array
= page_address(page
);
589 return &array
[iter
->next_page_idx
[cpu
]];
592 static struct notrace trace_entry
*
593 find_next_entry(struct trace_iterator
*iter
, int *ent_cpu
)
595 struct trace_array
*tr
= iter
->tr
;
596 struct trace_entry
*ent
, *next
= NULL
;
600 for_each_possible_cpu(cpu
) {
601 if (!head_page(tr
->data
[cpu
]))
603 ent
= trace_entry_idx(tr
, tr
->data
[cpu
], iter
, cpu
);
605 (!next
|| (long)(next
->idx
- ent
->idx
) > 0)) {
617 static void *find_next_entry_inc(struct trace_iterator
*iter
)
619 struct trace_entry
*next
;
622 next
= find_next_entry(iter
, &next_cpu
);
626 iter
->next_idx
[next_cpu
]++;
627 iter
->next_page_idx
[next_cpu
]++;
629 if (iter
->next_page_idx
[next_cpu
] >= ENTRIES_PER_PAGE
) {
630 struct trace_array_cpu
*data
= iter
->tr
->data
[next_cpu
];
632 iter
->next_page_idx
[next_cpu
] = 0;
633 iter
->next_page
[next_cpu
] =
634 iter
->next_page
[next_cpu
]->next
;
635 if (iter
->next_page
[next_cpu
] == &data
->trace_pages
)
636 iter
->next_page
[next_cpu
] =
637 data
->trace_pages
.next
;
640 iter
->prev_ent
= iter
->ent
;
641 iter
->prev_cpu
= iter
->cpu
;
644 iter
->cpu
= next_cpu
;
646 return next
? iter
: NULL
;
649 static notrace
void *s_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
651 struct trace_iterator
*iter
= m
->private;
652 void *last_ent
= iter
->ent
;
658 /* can't go backwards */
663 ent
= find_next_entry_inc(iter
);
667 while (ent
&& iter
->idx
< i
)
668 ent
= find_next_entry_inc(iter
);
672 if (last_ent
&& !ent
)
673 seq_puts(m
, "\n\nvim:ft=help\n");
678 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
680 struct trace_iterator
*iter
= m
->private;
685 mutex_lock(&trace_types_lock
);
687 if (!current_trace
|| current_trace
!= iter
->trace
)
690 atomic_inc(&trace_record_cmdline_disabled
);
692 /* let the tracer grab locks here if needed */
693 if (current_trace
->start
)
694 current_trace
->start(iter
);
696 if (*pos
!= iter
->pos
) {
700 iter
->prev_ent
= NULL
;
703 for_each_possible_cpu(i
) {
704 iter
->next_idx
[i
] = 0;
705 iter
->next_page
[i
] = NULL
;
708 for (p
= iter
; p
&& l
< *pos
; p
= s_next(m
, p
, &l
))
713 p
= s_next(m
, p
, &l
);
719 static void s_stop(struct seq_file
*m
, void *p
)
721 struct trace_iterator
*iter
= m
->private;
723 atomic_dec(&trace_record_cmdline_disabled
);
725 /* let the tracer release locks here if needed */
726 if (current_trace
&& current_trace
== iter
->trace
&& iter
->trace
->stop
)
727 iter
->trace
->stop(iter
);
729 mutex_unlock(&trace_types_lock
);
733 seq_print_sym_short(struct seq_file
*m
, const char *fmt
, unsigned long address
)
735 #ifdef CONFIG_KALLSYMS
736 char str
[KSYM_SYMBOL_LEN
];
738 kallsyms_lookup(address
, NULL
, NULL
, NULL
, str
);
740 seq_printf(m
, fmt
, str
);
745 seq_print_sym_offset(struct seq_file
*m
, const char *fmt
, unsigned long address
)
747 #ifdef CONFIG_KALLSYMS
748 char str
[KSYM_SYMBOL_LEN
];
750 sprint_symbol(str
, address
);
751 seq_printf(m
, fmt
, str
);
756 # define IP_FMT "%08lx"
758 # define IP_FMT "%016lx"
762 seq_print_ip_sym(struct seq_file
*m
, unsigned long ip
, unsigned long sym_flags
)
769 if (sym_flags
& TRACE_ITER_SYM_OFFSET
)
770 seq_print_sym_offset(m
, "%s", ip
);
772 seq_print_sym_short(m
, "%s", ip
);
774 if (sym_flags
& TRACE_ITER_SYM_ADDR
)
775 seq_printf(m
, " <" IP_FMT
">", ip
);
778 static notrace
void print_lat_help_header(struct seq_file
*m
)
780 seq_puts(m
, "# _------=> CPU# \n");
781 seq_puts(m
, "# / _-----=> irqs-off \n");
782 seq_puts(m
, "# | / _----=> need-resched \n");
783 seq_puts(m
, "# || / _---=> hardirq/softirq \n");
784 seq_puts(m
, "# ||| / _--=> preempt-depth \n");
785 seq_puts(m
, "# |||| / \n");
786 seq_puts(m
, "# ||||| delay \n");
787 seq_puts(m
, "# cmd pid ||||| time | caller \n");
788 seq_puts(m
, "# \\ / ||||| \\ | / \n");
791 static notrace
void print_func_help_header(struct seq_file
*m
)
793 seq_puts(m
, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
794 seq_puts(m
, "# | | | | |\n");
799 print_trace_header(struct seq_file
*m
, struct trace_iterator
*iter
)
801 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
802 struct trace_array
*tr
= iter
->tr
;
803 struct trace_array_cpu
*data
= tr
->data
[tr
->cpu
];
804 struct tracer
*type
= current_trace
;
805 unsigned long total
= 0;
806 unsigned long entries
= 0;
808 const char *name
= "preemption";
813 for_each_possible_cpu(cpu
) {
814 if (head_page(tr
->data
[cpu
])) {
815 total
+= tr
->data
[cpu
]->trace_idx
;
816 if (tr
->data
[cpu
]->trace_idx
> tr
->entries
)
817 entries
+= tr
->entries
;
819 entries
+= tr
->data
[cpu
]->trace_idx
;
823 seq_printf(m
, "%s latency trace v1.1.5 on %s\n",
825 seq_puts(m
, "-----------------------------------"
826 "---------------------------------\n");
827 seq_printf(m
, " latency: %lu us, #%lu/%lu, CPU#%d |"
828 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
829 nsecs_to_usecs(data
->saved_latency
),
833 #if defined(CONFIG_PREEMPT_NONE)
835 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
837 #elif defined(CONFIG_PREEMPT_DESKTOP)
842 /* These are reserved for later use */
845 seq_printf(m
, " #P:%d)\n", num_online_cpus());
849 seq_puts(m
, " -----------------\n");
850 seq_printf(m
, " | task: %.16s-%d "
851 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
852 data
->comm
, data
->pid
, data
->uid
, data
->nice
,
853 data
->policy
, data
->rt_priority
);
854 seq_puts(m
, " -----------------\n");
856 if (data
->critical_start
) {
857 seq_puts(m
, " => started at: ");
858 seq_print_ip_sym(m
, data
->critical_start
, sym_flags
);
859 seq_puts(m
, "\n => ended at: ");
860 seq_print_ip_sym(m
, data
->critical_end
, sym_flags
);
868 lat_print_generic(struct seq_file
*m
, struct trace_entry
*entry
, int cpu
)
870 int hardirq
, softirq
;
873 comm
= trace_find_cmdline(entry
->pid
);
875 seq_printf(m
, "%8.8s-%-5d ", comm
, entry
->pid
);
876 seq_printf(m
, "%d", cpu
);
877 seq_printf(m
, "%c%c",
878 (entry
->flags
& TRACE_FLAG_IRQS_OFF
) ? 'd' : '.',
879 ((entry
->flags
& TRACE_FLAG_NEED_RESCHED
) ? 'N' : '.'));
881 hardirq
= entry
->flags
& TRACE_FLAG_HARDIRQ
;
882 softirq
= entry
->flags
& TRACE_FLAG_SOFTIRQ
;
883 if (hardirq
&& softirq
)
896 if (entry
->preempt_count
)
897 seq_printf(m
, "%x", entry
->preempt_count
);
902 unsigned long preempt_mark_thresh
= 100;
905 lat_print_timestamp(struct seq_file
*m
, unsigned long long abs_usecs
,
906 unsigned long rel_usecs
)
908 seq_printf(m
, " %4lldus", abs_usecs
);
909 if (rel_usecs
> preempt_mark_thresh
)
911 else if (rel_usecs
> 1)
917 static const char state_to_char
[] = TASK_STATE_TO_CHAR_STR
;
920 print_lat_fmt(struct seq_file
*m
, struct trace_iterator
*iter
,
921 unsigned int trace_idx
, int cpu
)
923 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
924 struct trace_entry
*next_entry
= find_next_entry(iter
, NULL
);
925 unsigned long verbose
= (trace_flags
& TRACE_ITER_VERBOSE
);
926 struct trace_entry
*entry
= iter
->ent
;
927 unsigned long abs_usecs
;
928 unsigned long rel_usecs
;
934 rel_usecs
= ns2usecs(next_entry
->t
- entry
->t
);
935 abs_usecs
= ns2usecs(entry
->t
- iter
->tr
->time_start
);
938 comm
= trace_find_cmdline(entry
->pid
);
939 seq_printf(m
, "%16s %5d %d %d %08x %08x [%08lx]"
940 " %ld.%03ldms (+%ld.%03ldms): ",
942 entry
->pid
, cpu
, entry
->flags
,
943 entry
->preempt_count
, trace_idx
,
946 abs_usecs
% 1000, rel_usecs
/1000, rel_usecs
% 1000);
948 lat_print_generic(m
, entry
, cpu
);
949 lat_print_timestamp(m
, abs_usecs
, rel_usecs
);
951 switch (entry
->type
) {
953 seq_print_ip_sym(m
, entry
->fn
.ip
, sym_flags
);
955 seq_print_ip_sym(m
, entry
->fn
.parent_ip
, sym_flags
);
959 S
= entry
->ctx
.prev_state
< sizeof(state_to_char
) ?
960 state_to_char
[entry
->ctx
.prev_state
] : 'X';
961 comm
= trace_find_cmdline(entry
->ctx
.next_pid
);
962 seq_printf(m
, " %d:%d:%c --> %d:%d %s\n",
964 entry
->ctx
.prev_prio
,
967 entry
->ctx
.next_prio
,
971 seq_printf(m
, "Unknown type %d\n", entry
->type
);
975 static notrace
void sync_time_offset(struct trace_iterator
*iter
)
977 struct trace_array_cpu
*prev_array
, *array
;
978 struct trace_entry
*prev_entry
, *entry
;
982 prev_entry
= iter
->prev_ent
;
986 prev_array
= iter
->tr
->data
[iter
->prev_cpu
];
987 array
= iter
->tr
->data
[iter
->cpu
];
989 prev_t
= prev_entry
->t
+ prev_array
->time_offset
;
990 t
= entry
->t
+ array
->time_offset
;
993 * If time goes backwards we increase the offset of
994 * the current array, to not have observable time warps.
995 * This will quickly synchronize the time offsets of
999 array
->time_offset
+= prev_t
- t
;
1003 print_trace_fmt(struct seq_file
*m
, struct trace_iterator
*iter
)
1005 unsigned long sym_flags
= (trace_flags
& TRACE_ITER_SYM_MASK
);
1006 struct trace_entry
*entry
;
1007 unsigned long usec_rem
;
1008 unsigned long long t
;
1013 sync_time_offset(iter
);
1016 comm
= trace_find_cmdline(iter
->ent
->pid
);
1018 t
= ns2usecs(entry
->t
+ iter
->tr
->data
[iter
->cpu
]->time_offset
);
1019 usec_rem
= do_div(t
, 1000000ULL);
1020 secs
= (unsigned long)t
;
1022 seq_printf(m
, "%16s-%-5d ", comm
, entry
->pid
);
1023 seq_printf(m
, "[%02d] ", iter
->cpu
);
1024 seq_printf(m
, "%5lu.%06lu: ", secs
, usec_rem
);
1026 switch (entry
->type
) {
1028 seq_print_ip_sym(m
, entry
->fn
.ip
, sym_flags
);
1029 if ((sym_flags
& TRACE_ITER_PRINT_PARENT
) &&
1030 entry
->fn
.parent_ip
) {
1031 seq_printf(m
, " <-");
1032 seq_print_ip_sym(m
, entry
->fn
.parent_ip
, sym_flags
);
1034 seq_printf(m
, "\n");
1037 S
= entry
->ctx
.prev_state
< sizeof(state_to_char
) ?
1038 state_to_char
[entry
->ctx
.prev_state
] : 'X';
1039 seq_printf(m
, " %d:%d:%c ==> %d:%d\n",
1040 entry
->ctx
.prev_pid
,
1041 entry
->ctx
.prev_prio
,
1043 entry
->ctx
.next_pid
,
1044 entry
->ctx
.next_prio
);
1049 static int trace_empty(struct trace_iterator
*iter
)
1051 struct trace_array_cpu
*data
;
1054 for_each_possible_cpu(cpu
) {
1055 data
= iter
->tr
->data
[cpu
];
1057 if (head_page(data
) && data
->trace_idx
)
1063 static int s_show(struct seq_file
*m
, void *v
)
1065 struct trace_iterator
*iter
= v
;
1067 if (iter
->ent
== NULL
) {
1069 seq_printf(m
, "# tracer: %s\n", iter
->trace
->name
);
1072 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
) {
1073 /* print nothing if the buffers are empty */
1074 if (trace_empty(iter
))
1076 print_trace_header(m
, iter
);
1077 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1078 print_lat_help_header(m
);
1080 if (!(trace_flags
& TRACE_ITER_VERBOSE
))
1081 print_func_help_header(m
);
1084 if (iter
->iter_flags
& TRACE_FILE_LAT_FMT
)
1085 print_lat_fmt(m
, iter
, iter
->idx
, iter
->cpu
);
1087 print_trace_fmt(m
, iter
);
1093 static struct seq_operations tracer_seq_ops
= {
1100 static struct trace_iterator notrace
*
1101 __tracing_open(struct inode
*inode
, struct file
*file
, int *ret
)
1103 struct trace_iterator
*iter
;
1105 if (tracing_disabled
) {
1110 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
1116 mutex_lock(&trace_types_lock
);
1117 if (current_trace
&& current_trace
->print_max
)
1120 iter
->tr
= inode
->i_private
;
1121 iter
->trace
= current_trace
;
1124 /* TODO stop tracer */
1125 *ret
= seq_open(file
, &tracer_seq_ops
);
1127 struct seq_file
*m
= file
->private_data
;
1130 /* stop the trace while dumping */
1134 if (iter
->trace
&& iter
->trace
->open
)
1135 iter
->trace
->open(iter
);
1140 mutex_unlock(&trace_types_lock
);
1146 int tracing_open_generic(struct inode
*inode
, struct file
*filp
)
1148 if (tracing_disabled
)
1151 filp
->private_data
= inode
->i_private
;
1155 int tracing_release(struct inode
*inode
, struct file
*file
)
1157 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
1158 struct trace_iterator
*iter
= m
->private;
1160 mutex_lock(&trace_types_lock
);
1161 if (iter
->trace
&& iter
->trace
->close
)
1162 iter
->trace
->close(iter
);
1164 /* reenable tracing if it was previously enabled */
1167 mutex_unlock(&trace_types_lock
);
1169 seq_release(inode
, file
);
1174 static int tracing_open(struct inode
*inode
, struct file
*file
)
1178 __tracing_open(inode
, file
, &ret
);
1183 static int tracing_lt_open(struct inode
*inode
, struct file
*file
)
1185 struct trace_iterator
*iter
;
1188 iter
= __tracing_open(inode
, file
, &ret
);
1191 iter
->iter_flags
|= TRACE_FILE_LAT_FMT
;
1197 static notrace
void *
1198 t_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
1200 struct tracer
*t
= m
->private;
1212 static void *t_start(struct seq_file
*m
, loff_t
*pos
)
1214 struct tracer
*t
= m
->private;
1217 mutex_lock(&trace_types_lock
);
1218 for (; t
&& l
< *pos
; t
= t_next(m
, t
, &l
))
1224 static void t_stop(struct seq_file
*m
, void *p
)
1226 mutex_unlock(&trace_types_lock
);
1229 static int t_show(struct seq_file
*m
, void *v
)
1231 struct tracer
*t
= v
;
1236 seq_printf(m
, "%s", t
->name
);
1245 static struct seq_operations show_traces_seq_ops
= {
1252 static int show_traces_open(struct inode
*inode
, struct file
*file
)
1256 if (tracing_disabled
)
1259 ret
= seq_open(file
, &show_traces_seq_ops
);
1261 struct seq_file
*m
= file
->private_data
;
1262 m
->private = trace_types
;
1268 static struct file_operations tracing_fops
= {
1269 .open
= tracing_open
,
1271 .llseek
= seq_lseek
,
1272 .release
= tracing_release
,
1275 static struct file_operations tracing_lt_fops
= {
1276 .open
= tracing_lt_open
,
1278 .llseek
= seq_lseek
,
1279 .release
= tracing_release
,
1282 static struct file_operations show_traces_fops
= {
1283 .open
= show_traces_open
,
1285 .release
= seq_release
,
1289 tracing_iter_ctrl_read(struct file
*filp
, char __user
*ubuf
,
1290 size_t cnt
, loff_t
*ppos
)
1297 /* calulate max size */
1298 for (i
= 0; trace_options
[i
]; i
++) {
1299 len
+= strlen(trace_options
[i
]);
1300 len
+= 3; /* "no" and space */
1303 /* +2 for \n and \0 */
1304 buf
= kmalloc(len
+ 2, GFP_KERNEL
);
1308 for (i
= 0; trace_options
[i
]; i
++) {
1309 if (trace_flags
& (1 << i
))
1310 r
+= sprintf(buf
+ r
, "%s ", trace_options
[i
]);
1312 r
+= sprintf(buf
+ r
, "no%s ", trace_options
[i
]);
1315 r
+= sprintf(buf
+ r
, "\n");
1316 WARN_ON(r
>= len
+ 2);
1318 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
,
1327 tracing_iter_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
1328 size_t cnt
, loff_t
*ppos
)
1338 if (copy_from_user(&buf
, ubuf
, cnt
))
1343 if (strncmp(buf
, "no", 2) == 0) {
1348 for (i
= 0; trace_options
[i
]; i
++) {
1349 int len
= strlen(trace_options
[i
]);
1351 if (strncmp(cmp
, trace_options
[i
], len
) == 0) {
1353 trace_flags
&= ~(1 << i
);
1355 trace_flags
|= (1 << i
);
1365 static struct file_operations tracing_iter_fops
= {
1366 .open
= tracing_open_generic
,
1367 .read
= tracing_iter_ctrl_read
,
1368 .write
= tracing_iter_ctrl_write
,
1371 static const char readme_msg
[] =
1372 "tracing mini-HOWTO:\n\n"
1374 "# mount -t debugfs nodev /debug\n\n"
1375 "# cat /debug/tracing/available_tracers\n"
1376 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
1377 "# cat /debug/tracing/current_tracer\n"
1379 "# echo sched_switch > /debug/tracing/current_tracer\n"
1380 "# cat /debug/tracing/current_tracer\n"
1382 "# cat /debug/tracing/iter_ctrl\n"
1383 "noprint-parent nosym-offset nosym-addr noverbose\n"
1384 "# echo print-parent > /debug/tracing/iter_ctrl\n"
1385 "# echo 1 > /debug/tracing/tracing_enabled\n"
1386 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
1387 "echo 0 > /debug/tracing/tracing_enabled\n"
1391 tracing_readme_read(struct file
*filp
, char __user
*ubuf
,
1392 size_t cnt
, loff_t
*ppos
)
1394 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
1395 readme_msg
, strlen(readme_msg
));
1398 static struct file_operations tracing_readme_fops
= {
1399 .open
= tracing_open_generic
,
1400 .read
= tracing_readme_read
,
1405 tracing_ctrl_read(struct file
*filp
, char __user
*ubuf
,
1406 size_t cnt
, loff_t
*ppos
)
1408 struct trace_array
*tr
= filp
->private_data
;
1412 r
= sprintf(buf
, "%ld\n", tr
->ctrl
);
1413 return simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
1417 tracing_ctrl_write(struct file
*filp
, const char __user
*ubuf
,
1418 size_t cnt
, loff_t
*ppos
)
1420 struct trace_array
*tr
= filp
->private_data
;
1427 if (copy_from_user(&buf
, ubuf
, cnt
))
1432 val
= simple_strtoul(buf
, NULL
, 10);
1436 mutex_lock(&trace_types_lock
);
1437 if (tr
->ctrl
^ val
) {
1445 if (current_trace
&& current_trace
->ctrl_update
)
1446 current_trace
->ctrl_update(tr
);
1448 mutex_unlock(&trace_types_lock
);
1456 tracing_set_trace_read(struct file
*filp
, char __user
*ubuf
,
1457 size_t cnt
, loff_t
*ppos
)
1459 char buf
[max_tracer_type_len
+2];
1462 mutex_lock(&trace_types_lock
);
1464 r
= sprintf(buf
, "%s\n", current_trace
->name
);
1466 r
= sprintf(buf
, "\n");
1467 mutex_unlock(&trace_types_lock
);
1469 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
1474 tracing_set_trace_write(struct file
*filp
, const char __user
*ubuf
,
1475 size_t cnt
, loff_t
*ppos
)
1477 struct trace_array
*tr
= &global_trace
;
1479 char buf
[max_tracer_type_len
+1];
1482 if (cnt
> max_tracer_type_len
)
1483 cnt
= max_tracer_type_len
;
1485 if (copy_from_user(&buf
, ubuf
, cnt
))
1490 /* strip ending whitespace. */
1491 for (i
= cnt
- 1; i
> 0 && isspace(buf
[i
]); i
--)
1494 mutex_lock(&trace_types_lock
);
1495 for (t
= trace_types
; t
; t
= t
->next
) {
1496 if (strcmp(t
->name
, buf
) == 0)
1499 if (!t
|| t
== current_trace
)
1502 if (current_trace
&& current_trace
->reset
)
1503 current_trace
->reset(tr
);
1510 mutex_unlock(&trace_types_lock
);
1518 tracing_max_lat_read(struct file
*filp
, char __user
*ubuf
,
1519 size_t cnt
, loff_t
*ppos
)
1521 unsigned long *ptr
= filp
->private_data
;
1525 r
= snprintf(buf
, 64, "%ld\n",
1526 *ptr
== (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr
));
1529 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
1534 tracing_max_lat_write(struct file
*filp
, const char __user
*ubuf
,
1535 size_t cnt
, loff_t
*ppos
)
1537 long *ptr
= filp
->private_data
;
1544 if (copy_from_user(&buf
, ubuf
, cnt
))
1549 val
= simple_strtoul(buf
, NULL
, 10);
1556 static struct file_operations tracing_max_lat_fops
= {
1557 .open
= tracing_open_generic
,
1558 .read
= tracing_max_lat_read
,
1559 .write
= tracing_max_lat_write
,
1562 static struct file_operations tracing_ctrl_fops
= {
1563 .open
= tracing_open_generic
,
1564 .read
= tracing_ctrl_read
,
1565 .write
= tracing_ctrl_write
,
1568 static struct file_operations set_tracer_fops
= {
1569 .open
= tracing_open_generic
,
1570 .read
= tracing_set_trace_read
,
1571 .write
= tracing_set_trace_write
,
1574 #ifdef CONFIG_DYNAMIC_FTRACE
1577 tracing_read_long(struct file
*filp
, char __user
*ubuf
,
1578 size_t cnt
, loff_t
*ppos
)
1580 unsigned long *p
= filp
->private_data
;
1584 r
= sprintf(buf
, "%ld\n", *p
);
1585 return simple_read_from_buffer(ubuf
, cnt
, ppos
,
1589 static struct file_operations tracing_read_long_fops
= {
1590 .open
= tracing_open_generic
,
1591 .read
= tracing_read_long
,
1595 static struct dentry
*d_tracer
;
1597 struct dentry
*tracing_init_dentry(void)
1604 d_tracer
= debugfs_create_dir("tracing", NULL
);
1606 if (!d_tracer
&& !once
) {
1608 pr_warning("Could not create debugfs directory 'tracing'\n");
1615 #ifdef CONFIG_FTRACE_SELFTEST
1616 /* Let selftest have access to static functions in this file */
1617 #include "trace_selftest.c"
1620 static __init
void tracer_init_debugfs(void)
1622 struct dentry
*d_tracer
;
1623 struct dentry
*entry
;
1625 d_tracer
= tracing_init_dentry();
1627 entry
= debugfs_create_file("tracing_enabled", 0644, d_tracer
,
1628 &global_trace
, &tracing_ctrl_fops
);
1630 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
1632 entry
= debugfs_create_file("iter_ctrl", 0644, d_tracer
,
1633 NULL
, &tracing_iter_fops
);
1635 pr_warning("Could not create debugfs 'iter_ctrl' entry\n");
1637 entry
= debugfs_create_file("latency_trace", 0444, d_tracer
,
1638 &global_trace
, &tracing_lt_fops
);
1640 pr_warning("Could not create debugfs 'latency_trace' entry\n");
1642 entry
= debugfs_create_file("trace", 0444, d_tracer
,
1643 &global_trace
, &tracing_fops
);
1645 pr_warning("Could not create debugfs 'trace' entry\n");
1647 entry
= debugfs_create_file("available_tracers", 0444, d_tracer
,
1648 &global_trace
, &show_traces_fops
);
1650 pr_warning("Could not create debugfs 'trace' entry\n");
1652 entry
= debugfs_create_file("current_tracer", 0444, d_tracer
,
1653 &global_trace
, &set_tracer_fops
);
1655 pr_warning("Could not create debugfs 'trace' entry\n");
1657 entry
= debugfs_create_file("tracing_max_latency", 0644, d_tracer
,
1658 &tracing_max_latency
,
1659 &tracing_max_lat_fops
);
1661 pr_warning("Could not create debugfs "
1662 "'tracing_max_latency' entry\n");
1664 entry
= debugfs_create_file("tracing_thresh", 0644, d_tracer
,
1665 &tracing_thresh
, &tracing_max_lat_fops
);
1667 pr_warning("Could not create debugfs "
1668 "'tracing_threash' entry\n");
1669 entry
= debugfs_create_file("README", 0644, d_tracer
,
1670 NULL
, &tracing_readme_fops
);
1672 pr_warning("Could not create debugfs 'README' entry\n");
1675 #ifdef CONFIG_DYNAMIC_FTRACE
1676 entry
= debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer
,
1677 &ftrace_update_tot_cnt
,
1678 &tracing_read_long_fops
);
1680 pr_warning("Could not create debugfs "
1681 "'dyn_ftrace_total_info' entry\n");
1685 /* dummy trace to disable tracing */
1686 static struct tracer no_tracer __read_mostly
=
1691 static int trace_alloc_page(void)
1693 struct trace_array_cpu
*data
;
1694 struct page
*page
, *tmp
;
1699 /* first allocate a page for each CPU */
1700 for_each_possible_cpu(i
) {
1701 array
= (void *)__get_free_page(GFP_KERNEL
);
1702 if (array
== NULL
) {
1703 printk(KERN_ERR
"tracer: failed to allocate page"
1704 "for trace buffer!\n");
1708 page
= virt_to_page(array
);
1709 list_add(&page
->lru
, &pages
);
1711 /* Only allocate if we are actually using the max trace */
1712 #ifdef CONFIG_TRACER_MAX_TRACE
1713 array
= (void *)__get_free_page(GFP_KERNEL
);
1714 if (array
== NULL
) {
1715 printk(KERN_ERR
"tracer: failed to allocate page"
1716 "for trace buffer!\n");
1719 page
= virt_to_page(array
);
1720 list_add(&page
->lru
, &pages
);
1724 /* Now that we successfully allocate a page per CPU, add them */
1725 for_each_possible_cpu(i
) {
1726 data
= global_trace
.data
[i
];
1727 page
= list_entry(pages
.next
, struct page
, lru
);
1728 list_del_init(&page
->lru
);
1729 list_add_tail(&page
->lru
, &data
->trace_pages
);
1732 #ifdef CONFIG_TRACER_MAX_TRACE
1733 data
= max_tr
.data
[i
];
1734 page
= list_entry(pages
.next
, struct page
, lru
);
1735 list_del_init(&page
->lru
);
1736 list_add_tail(&page
->lru
, &data
->trace_pages
);
1740 global_trace
.entries
+= ENTRIES_PER_PAGE
;
1745 list_for_each_entry_safe(page
, tmp
, &pages
, lru
) {
1746 list_del_init(&page
->lru
);
1752 __init
static int tracer_alloc_buffers(void)
1754 struct trace_array_cpu
*data
;
1761 /* Allocate the first page for all buffers */
1762 for_each_possible_cpu(i
) {
1763 data
= global_trace
.data
[i
] = &per_cpu(global_trace_cpu
, i
);
1764 max_tr
.data
[i
] = &per_cpu(max_data
, i
);
1766 array
= (void *)__get_free_page(GFP_KERNEL
);
1767 if (array
== NULL
) {
1768 printk(KERN_ERR
"tracer: failed to allocate page"
1769 "for trace buffer!\n");
1773 /* set the array to the list */
1774 INIT_LIST_HEAD(&data
->trace_pages
);
1775 page
= virt_to_page(array
);
1776 list_add(&page
->lru
, &data
->trace_pages
);
1777 /* use the LRU flag to differentiate the two buffers */
1780 /* Only allocate if we are actually using the max trace */
1781 #ifdef CONFIG_TRACER_MAX_TRACE
1782 array
= (void *)__get_free_page(GFP_KERNEL
);
1783 if (array
== NULL
) {
1784 printk(KERN_ERR
"tracer: failed to allocate page"
1785 "for trace buffer!\n");
1789 INIT_LIST_HEAD(&max_tr
.data
[i
]->trace_pages
);
1790 page
= virt_to_page(array
);
1791 list_add(&page
->lru
, &max_tr
.data
[i
]->trace_pages
);
1797 * Since we allocate by orders of pages, we may be able to
1800 global_trace
.entries
= ENTRIES_PER_PAGE
;
1803 while (global_trace
.entries
< trace_nr_entries
) {
1804 if (trace_alloc_page())
1808 max_tr
.entries
= global_trace
.entries
;
1810 pr_info("tracer: %d pages allocated for %ld",
1811 pages
, trace_nr_entries
);
1812 pr_info(" entries of %ld bytes\n", (long)TRACE_ENTRY_SIZE
);
1813 pr_info(" actual entries %ld\n", global_trace
.entries
);
1815 tracer_init_debugfs();
1817 trace_init_cmdlines();
1819 register_tracer(&no_tracer
);
1820 current_trace
= &no_tracer
;
1822 /* All seems OK, enable tracing */
1823 tracing_disabled
= 0;
1828 for (i
-- ; i
>= 0; i
--) {
1829 struct page
*page
, *tmp
;
1830 struct trace_array_cpu
*data
= global_trace
.data
[i
];
1833 list_for_each_entry_safe(page
, tmp
,
1834 &data
->trace_pages
, lru
) {
1835 list_del_init(&page
->lru
);
1840 #ifdef CONFIG_TRACER_MAX_TRACE
1841 data
= max_tr
.data
[i
];
1843 list_for_each_entry_safe(page
, tmp
,
1844 &data
->trace_pages
, lru
) {
1845 list_del_init(&page
->lru
);
1854 fs_initcall(tracer_alloc_buffers
);