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>
31 #include <linux/stacktrace.h>
35 unsigned long __read_mostly tracing_max_latency = (cycle_t)ULONG_MAX;
36 unsigned long __read_mostly tracing_thresh;
38 static int tracing_disabled = 1;
41 ns2usecs(cycle_t nsec)
48 cycle_t ftrace_now(int cpu)
50 return cpu_clock(cpu);
53 static struct trace_array global_trace;
55 static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
57 static struct trace_array max_tr;
59 static DEFINE_PER_CPU(struct trace_array_cpu, max_data);
61 static int tracer_enabled = 1;
62 static unsigned long trace_nr_entries = 65536UL;
64 static struct tracer *trace_types __read_mostly;
65 static struct tracer *current_trace __read_mostly;
66 static int max_tracer_type_len;
68 static DEFINE_MUTEX(trace_types_lock);
69 static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
71 unsigned long trace_flags = TRACE_ITER_PRINT_PARENT;
73 void trace_wake_up(void)
76 * The runqueue_is_locked() can fail, but this is the best we
79 if (!(trace_flags & TRACE_ITER_BLOCK) && !runqueue_is_locked())
83 #define ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(struct trace_entry))
85 static int __init set_nr_entries(char *str)
89 trace_nr_entries = simple_strtoul(str, &str, 0);
92 __setup("trace_entries=", set_nr_entries);
94 unsigned long nsecs_to_usecs(unsigned long nsecs)
99 enum trace_flag_type {
100 TRACE_FLAG_IRQS_OFF = 0x01,
101 TRACE_FLAG_NEED_RESCHED = 0x02,
102 TRACE_FLAG_HARDIRQ = 0x04,
103 TRACE_FLAG_SOFTIRQ = 0x08,
106 #define TRACE_ITER_SYM_MASK \
107 (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
109 /* These must match the bit postions above */
110 static const char *trace_options[] = {
124 static raw_spinlock_t ftrace_max_lock =
125 (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
128 * Copy the new maximum trace into the separate maximum-trace
129 * structure. (this way the maximum trace is permanently saved,
130 * for later retrieval via /debugfs/tracing/latency_trace)
133 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
135 struct trace_array_cpu *data = tr->data[cpu];
138 max_tr.time_start = data->preempt_timestamp;
140 data = max_tr.data[cpu];
141 data->saved_latency = tracing_max_latency;
143 memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
144 data->pid = tsk->pid;
145 data->uid = tsk->uid;
146 data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
147 data->policy = tsk->policy;
148 data->rt_priority = tsk->rt_priority;
150 /* record this tasks comm */
151 tracing_record_cmdline(current);
154 void check_pages(struct trace_array_cpu *data)
156 struct page *page, *tmp;
158 BUG_ON(data->trace_pages.next->prev != &data->trace_pages);
159 BUG_ON(data->trace_pages.prev->next != &data->trace_pages);
161 list_for_each_entry_safe(page, tmp, &data->trace_pages, lru) {
162 BUG_ON(page->lru.next->prev != &page->lru);
163 BUG_ON(page->lru.prev->next != &page->lru);
167 void *head_page(struct trace_array_cpu *data)
172 if (list_empty(&data->trace_pages))
175 page = list_entry(data->trace_pages.next, struct page, lru);
176 BUG_ON(&page->lru == &data->trace_pages);
178 return page_address(page);
182 trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
184 int len = (PAGE_SIZE - 1) - s->len;
192 ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
195 /* If we can't write it all, don't bother writing anything */
205 trace_seq_puts(struct trace_seq *s, const char *str)
207 int len = strlen(str);
209 if (len > ((PAGE_SIZE - 1) - s->len))
212 memcpy(s->buffer + s->len, str, len);
219 trace_seq_putc(struct trace_seq *s, unsigned char c)
221 if (s->len >= (PAGE_SIZE - 1))
224 s->buffer[s->len++] = c;
230 trace_seq_putmem(struct trace_seq *s, void *mem, size_t len)
232 if (len > ((PAGE_SIZE - 1) - s->len))
235 memcpy(s->buffer + s->len, mem, len);
244 trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len)
246 unsigned char hex[HEX_CHARS];
251 BUG_ON(len >= HEX_CHARS);
256 for (i = 0, j = 0; i < len; i++) {
258 for (i = len-1, j = 0; i >= 0; i--) {
262 hex[j] = byte & 0x0f;
279 return trace_seq_putmem(s, hex, j);
283 trace_seq_reset(struct trace_seq *s)
289 trace_print_seq(struct seq_file *m, struct trace_seq *s)
291 int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
294 seq_puts(m, s->buffer);
300 flip_trace(struct trace_array_cpu *tr1, struct trace_array_cpu *tr2)
302 struct list_head flip_pages;
304 INIT_LIST_HEAD(&flip_pages);
306 memcpy(&tr1->trace_head_idx, &tr2->trace_head_idx,
307 sizeof(struct trace_array_cpu) -
308 offsetof(struct trace_array_cpu, trace_head_idx));
312 list_splice_init(&tr1->trace_pages, &flip_pages);
313 list_splice_init(&tr2->trace_pages, &tr1->trace_pages);
314 list_splice_init(&flip_pages, &tr2->trace_pages);
315 BUG_ON(!list_empty(&flip_pages));
321 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
323 struct trace_array_cpu *data;
326 WARN_ON_ONCE(!irqs_disabled());
327 __raw_spin_lock(&ftrace_max_lock);
328 /* clear out all the previous traces */
329 for_each_possible_cpu(i) {
331 flip_trace(max_tr.data[i], data);
335 __update_max_tr(tr, tsk, cpu);
336 __raw_spin_unlock(&ftrace_max_lock);
340 * update_max_tr_single - only copy one trace over, and reset the rest
342 * @tsk - task with the latency
343 * @cpu - the cpu of the buffer to copy.
346 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
348 struct trace_array_cpu *data = tr->data[cpu];
351 WARN_ON_ONCE(!irqs_disabled());
352 __raw_spin_lock(&ftrace_max_lock);
353 for_each_possible_cpu(i)
354 tracing_reset(max_tr.data[i]);
356 flip_trace(max_tr.data[cpu], data);
359 __update_max_tr(tr, tsk, cpu);
360 __raw_spin_unlock(&ftrace_max_lock);
363 int register_tracer(struct tracer *type)
370 pr_info("Tracer must have a name\n");
374 mutex_lock(&trace_types_lock);
375 for (t = trace_types; t; t = t->next) {
376 if (strcmp(type->name, t->name) == 0) {
378 pr_info("Trace %s already registered\n",
385 #ifdef CONFIG_FTRACE_STARTUP_TEST
386 if (type->selftest) {
387 struct tracer *saved_tracer = current_trace;
388 struct trace_array_cpu *data;
389 struct trace_array *tr = &global_trace;
390 int saved_ctrl = tr->ctrl;
393 * Run a selftest on this tracer.
394 * Here we reset the trace buffer, and set the current
395 * tracer to be this tracer. The tracer can then run some
396 * internal tracing to verify that everything is in order.
397 * If we fail, we do not register this tracer.
399 for_each_possible_cpu(i) {
401 if (!head_page(data))
405 current_trace = type;
407 /* the test is responsible for initializing and enabling */
408 pr_info("Testing tracer %s: ", type->name);
409 ret = type->selftest(type, tr);
410 /* the test is responsible for resetting too */
411 current_trace = saved_tracer;
412 tr->ctrl = saved_ctrl;
414 printk(KERN_CONT "FAILED!\n");
417 /* Only reset on passing, to avoid touching corrupted buffers */
418 for_each_possible_cpu(i) {
420 if (!head_page(data))
424 printk(KERN_CONT "PASSED\n");
428 type->next = trace_types;
430 len = strlen(type->name);
431 if (len > max_tracer_type_len)
432 max_tracer_type_len = len;
435 mutex_unlock(&trace_types_lock);
440 void unregister_tracer(struct tracer *type)
445 mutex_lock(&trace_types_lock);
446 for (t = &trace_types; *t; t = &(*t)->next) {
450 pr_info("Trace %s not registered\n", type->name);
455 if (strlen(type->name) != max_tracer_type_len)
458 max_tracer_type_len = 0;
459 for (t = &trace_types; *t; t = &(*t)->next) {
460 len = strlen((*t)->name);
461 if (len > max_tracer_type_len)
462 max_tracer_type_len = len;
465 mutex_unlock(&trace_types_lock);
468 void tracing_reset(struct trace_array_cpu *data)
471 data->trace_head = data->trace_tail = head_page(data);
472 data->trace_head_idx = 0;
473 data->trace_tail_idx = 0;
476 #define SAVED_CMDLINES 128
477 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
478 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
479 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
480 static int cmdline_idx;
481 static DEFINE_SPINLOCK(trace_cmdline_lock);
482 atomic_t trace_record_cmdline_disabled;
484 static void trace_init_cmdlines(void)
486 memset(&map_pid_to_cmdline, -1, sizeof(map_pid_to_cmdline));
487 memset(&map_cmdline_to_pid, -1, sizeof(map_cmdline_to_pid));
491 void trace_stop_cmdline_recording(void);
493 static void trace_save_cmdline(struct task_struct *tsk)
498 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
502 * It's not the end of the world if we don't get
503 * the lock, but we also don't want to spin
504 * nor do we want to disable interrupts,
505 * so if we miss here, then better luck next time.
507 if (!spin_trylock(&trace_cmdline_lock))
510 idx = map_pid_to_cmdline[tsk->pid];
511 if (idx >= SAVED_CMDLINES) {
512 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
514 map = map_cmdline_to_pid[idx];
515 if (map <= PID_MAX_DEFAULT)
516 map_pid_to_cmdline[map] = (unsigned)-1;
518 map_pid_to_cmdline[tsk->pid] = idx;
523 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
525 spin_unlock(&trace_cmdline_lock);
528 static char *trace_find_cmdline(int pid)
530 char *cmdline = "<...>";
536 if (pid > PID_MAX_DEFAULT)
539 map = map_pid_to_cmdline[pid];
540 if (map >= SAVED_CMDLINES)
543 cmdline = saved_cmdlines[map];
549 void tracing_record_cmdline(struct task_struct *tsk)
551 if (atomic_read(&trace_record_cmdline_disabled))
554 trace_save_cmdline(tsk);
557 static inline struct list_head *
558 trace_next_list(struct trace_array_cpu *data, struct list_head *next)
561 * Roundrobin - but skip the head (which is not a real page):
564 if (unlikely(next == &data->trace_pages))
566 BUG_ON(next == &data->trace_pages);
572 trace_next_page(struct trace_array_cpu *data, void *addr)
574 struct list_head *next;
577 page = virt_to_page(addr);
579 next = trace_next_list(data, &page->lru);
580 page = list_entry(next, struct page, lru);
582 return page_address(page);
585 static inline struct trace_entry *
586 tracing_get_trace_entry(struct trace_array *tr, struct trace_array_cpu *data)
588 unsigned long idx, idx_next;
589 struct trace_entry *entry;
592 idx = data->trace_head_idx;
595 BUG_ON(idx * TRACE_ENTRY_SIZE >= PAGE_SIZE);
597 entry = data->trace_head + idx * TRACE_ENTRY_SIZE;
599 if (unlikely(idx_next >= ENTRIES_PER_PAGE)) {
600 data->trace_head = trace_next_page(data, data->trace_head);
604 if (data->trace_head == data->trace_tail &&
605 idx_next == data->trace_tail_idx) {
607 data->trace_tail_idx++;
608 if (data->trace_tail_idx >= ENTRIES_PER_PAGE) {
610 trace_next_page(data, data->trace_tail);
611 data->trace_tail_idx = 0;
615 data->trace_head_idx = idx_next;
621 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags)
623 struct task_struct *tsk = current;
626 pc = preempt_count();
628 entry->preempt_count = pc & 0xff;
629 entry->pid = (tsk) ? tsk->pid : 0;
630 entry->t = ftrace_now(raw_smp_processor_id());
631 entry->flags = (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
632 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
633 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
634 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
638 trace_function(struct trace_array *tr, struct trace_array_cpu *data,
639 unsigned long ip, unsigned long parent_ip, unsigned long flags)
641 struct trace_entry *entry;
642 unsigned long irq_flags;
644 raw_local_irq_save(irq_flags);
645 __raw_spin_lock(&data->lock);
646 entry = tracing_get_trace_entry(tr, data);
647 tracing_generic_entry_update(entry, flags);
648 entry->type = TRACE_FN;
650 entry->fn.parent_ip = parent_ip;
651 __raw_spin_unlock(&data->lock);
652 raw_local_irq_restore(irq_flags);
656 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
657 unsigned long ip, unsigned long parent_ip, unsigned long flags)
659 if (likely(!atomic_read(&data->disabled)))
660 trace_function(tr, data, ip, parent_ip, flags);
664 __trace_special(void *__tr, void *__data,
665 unsigned long arg1, unsigned long arg2, unsigned long arg3)
667 struct trace_array_cpu *data = __data;
668 struct trace_array *tr = __tr;
669 struct trace_entry *entry;
670 unsigned long irq_flags;
672 raw_local_irq_save(irq_flags);
673 __raw_spin_lock(&data->lock);
674 entry = tracing_get_trace_entry(tr, data);
675 tracing_generic_entry_update(entry, 0);
676 entry->type = TRACE_SPECIAL;
677 entry->special.arg1 = arg1;
678 entry->special.arg2 = arg2;
679 entry->special.arg3 = arg3;
680 __raw_spin_unlock(&data->lock);
681 raw_local_irq_restore(irq_flags);
686 void __trace_stack(struct trace_array *tr,
687 struct trace_array_cpu *data,
691 struct trace_entry *entry;
692 struct stack_trace trace;
694 if (!(trace_flags & TRACE_ITER_STACKTRACE))
697 entry = tracing_get_trace_entry(tr, data);
698 tracing_generic_entry_update(entry, flags);
699 entry->type = TRACE_STACK;
701 memset(&entry->stack, 0, sizeof(entry->stack));
703 trace.nr_entries = 0;
704 trace.max_entries = FTRACE_STACK_ENTRIES;
706 trace.entries = entry->stack.caller;
708 save_stack_trace(&trace);
712 tracing_sched_switch_trace(struct trace_array *tr,
713 struct trace_array_cpu *data,
714 struct task_struct *prev,
715 struct task_struct *next,
718 struct trace_entry *entry;
719 unsigned long irq_flags;
721 raw_local_irq_save(irq_flags);
722 __raw_spin_lock(&data->lock);
723 entry = tracing_get_trace_entry(tr, data);
724 tracing_generic_entry_update(entry, flags);
725 entry->type = TRACE_CTX;
726 entry->ctx.prev_pid = prev->pid;
727 entry->ctx.prev_prio = prev->prio;
728 entry->ctx.prev_state = prev->state;
729 entry->ctx.next_pid = next->pid;
730 entry->ctx.next_prio = next->prio;
731 entry->ctx.next_state = next->state;
732 __trace_stack(tr, data, flags, 4);
733 __raw_spin_unlock(&data->lock);
734 raw_local_irq_restore(irq_flags);
738 tracing_sched_wakeup_trace(struct trace_array *tr,
739 struct trace_array_cpu *data,
740 struct task_struct *wakee,
741 struct task_struct *curr,
744 struct trace_entry *entry;
745 unsigned long irq_flags;
747 raw_local_irq_save(irq_flags);
748 __raw_spin_lock(&data->lock);
749 entry = tracing_get_trace_entry(tr, data);
750 tracing_generic_entry_update(entry, flags);
751 entry->type = TRACE_WAKE;
752 entry->ctx.prev_pid = curr->pid;
753 entry->ctx.prev_prio = curr->prio;
754 entry->ctx.prev_state = curr->state;
755 entry->ctx.next_pid = wakee->pid;
756 entry->ctx.next_prio = wakee->prio;
757 entry->ctx.next_state = wakee->state;
758 __trace_stack(tr, data, flags, 5);
759 __raw_spin_unlock(&data->lock);
760 raw_local_irq_restore(irq_flags);
767 function_trace_call(unsigned long ip, unsigned long parent_ip)
769 struct trace_array *tr = &global_trace;
770 struct trace_array_cpu *data;
775 if (unlikely(!tracer_enabled))
778 local_irq_save(flags);
779 cpu = raw_smp_processor_id();
780 data = tr->data[cpu];
781 disabled = atomic_inc_return(&data->disabled);
783 if (likely(disabled == 1))
784 trace_function(tr, data, ip, parent_ip, flags);
786 atomic_dec(&data->disabled);
787 local_irq_restore(flags);
790 static struct ftrace_ops trace_ops __read_mostly =
792 .func = function_trace_call,
795 void tracing_start_function_trace(void)
797 register_ftrace_function(&trace_ops);
800 void tracing_stop_function_trace(void)
802 unregister_ftrace_function(&trace_ops);
806 enum trace_file_type {
807 TRACE_FILE_LAT_FMT = 1,
810 static struct trace_entry *
811 trace_entry_idx(struct trace_array *tr, struct trace_array_cpu *data,
812 struct trace_iterator *iter, int cpu)
815 struct trace_entry *array;
817 if (iter->next_idx[cpu] >= tr->entries ||
818 iter->next_idx[cpu] >= data->trace_idx ||
819 (data->trace_head == data->trace_tail &&
820 data->trace_head_idx == data->trace_tail_idx))
823 if (!iter->next_page[cpu]) {
824 /* Initialize the iterator for this cpu trace buffer */
825 WARN_ON(!data->trace_tail);
826 page = virt_to_page(data->trace_tail);
827 iter->next_page[cpu] = &page->lru;
828 iter->next_page_idx[cpu] = data->trace_tail_idx;
831 page = list_entry(iter->next_page[cpu], struct page, lru);
832 BUG_ON(&data->trace_pages == &page->lru);
834 array = page_address(page);
836 WARN_ON(iter->next_page_idx[cpu] >= ENTRIES_PER_PAGE);
837 return &array[iter->next_page_idx[cpu]];
840 static struct trace_entry *
841 find_next_entry(struct trace_iterator *iter, int *ent_cpu)
843 struct trace_array *tr = iter->tr;
844 struct trace_entry *ent, *next = NULL;
848 for_each_possible_cpu(cpu) {
849 if (!head_page(tr->data[cpu]))
851 ent = trace_entry_idx(tr, tr->data[cpu], iter, cpu);
853 * Pick the entry with the smallest timestamp:
855 if (ent && (!next || ent->t < next->t)) {
867 static void trace_iterator_increment(struct trace_iterator *iter)
870 iter->next_idx[iter->cpu]++;
871 iter->next_page_idx[iter->cpu]++;
873 if (iter->next_page_idx[iter->cpu] >= ENTRIES_PER_PAGE) {
874 struct trace_array_cpu *data = iter->tr->data[iter->cpu];
876 iter->next_page_idx[iter->cpu] = 0;
877 iter->next_page[iter->cpu] =
878 trace_next_list(data, iter->next_page[iter->cpu]);
882 static void trace_consume(struct trace_iterator *iter)
884 struct trace_array_cpu *data = iter->tr->data[iter->cpu];
886 data->trace_tail_idx++;
887 if (data->trace_tail_idx >= ENTRIES_PER_PAGE) {
888 data->trace_tail = trace_next_page(data, data->trace_tail);
889 data->trace_tail_idx = 0;
892 /* Check if we empty it, then reset the index */
893 if (data->trace_head == data->trace_tail &&
894 data->trace_head_idx == data->trace_tail_idx)
898 static void *find_next_entry_inc(struct trace_iterator *iter)
900 struct trace_entry *next;
903 next = find_next_entry(iter, &next_cpu);
905 iter->prev_ent = iter->ent;
906 iter->prev_cpu = iter->cpu;
909 iter->cpu = next_cpu;
912 trace_iterator_increment(iter);
914 return next ? iter : NULL;
917 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
919 struct trace_iterator *iter = m->private;
920 void *last_ent = iter->ent;
926 /* can't go backwards */
931 ent = find_next_entry_inc(iter);
935 while (ent && iter->idx < i)
936 ent = find_next_entry_inc(iter);
940 if (last_ent && !ent)
941 seq_puts(m, "\n\nvim:ft=help\n");
946 static void *s_start(struct seq_file *m, loff_t *pos)
948 struct trace_iterator *iter = m->private;
953 mutex_lock(&trace_types_lock);
955 if (!current_trace || current_trace != iter->trace) {
956 mutex_unlock(&trace_types_lock);
960 atomic_inc(&trace_record_cmdline_disabled);
962 /* let the tracer grab locks here if needed */
963 if (current_trace->start)
964 current_trace->start(iter);
966 if (*pos != iter->pos) {
970 iter->prev_ent = NULL;
973 for_each_possible_cpu(i) {
974 iter->next_idx[i] = 0;
975 iter->next_page[i] = NULL;
978 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
983 p = s_next(m, p, &l);
989 static void s_stop(struct seq_file *m, void *p)
991 struct trace_iterator *iter = m->private;
993 atomic_dec(&trace_record_cmdline_disabled);
995 /* let the tracer release locks here if needed */
996 if (current_trace && current_trace == iter->trace && iter->trace->stop)
997 iter->trace->stop(iter);
999 mutex_unlock(&trace_types_lock);
1003 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
1005 #ifdef CONFIG_KALLSYMS
1006 char str[KSYM_SYMBOL_LEN];
1008 kallsyms_lookup(address, NULL, NULL, NULL, str);
1010 return trace_seq_printf(s, fmt, str);
1016 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
1017 unsigned long address)
1019 #ifdef CONFIG_KALLSYMS
1020 char str[KSYM_SYMBOL_LEN];
1022 sprint_symbol(str, address);
1023 return trace_seq_printf(s, fmt, str);
1028 #ifndef CONFIG_64BIT
1029 # define IP_FMT "%08lx"
1031 # define IP_FMT "%016lx"
1035 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
1040 return trace_seq_printf(s, "0");
1042 if (sym_flags & TRACE_ITER_SYM_OFFSET)
1043 ret = seq_print_sym_offset(s, "%s", ip);
1045 ret = seq_print_sym_short(s, "%s", ip);
1050 if (sym_flags & TRACE_ITER_SYM_ADDR)
1051 ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
1055 static void print_lat_help_header(struct seq_file *m)
1057 seq_puts(m, "# _------=> CPU# \n");
1058 seq_puts(m, "# / _-----=> irqs-off \n");
1059 seq_puts(m, "# | / _----=> need-resched \n");
1060 seq_puts(m, "# || / _---=> hardirq/softirq \n");
1061 seq_puts(m, "# ||| / _--=> preempt-depth \n");
1062 seq_puts(m, "# |||| / \n");
1063 seq_puts(m, "# ||||| delay \n");
1064 seq_puts(m, "# cmd pid ||||| time | caller \n");
1065 seq_puts(m, "# \\ / ||||| \\ | / \n");
1068 static void print_func_help_header(struct seq_file *m)
1070 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1071 seq_puts(m, "# | | | | |\n");
1076 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
1078 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1079 struct trace_array *tr = iter->tr;
1080 struct trace_array_cpu *data = tr->data[tr->cpu];
1081 struct tracer *type = current_trace;
1082 unsigned long total = 0;
1083 unsigned long entries = 0;
1085 const char *name = "preemption";
1090 for_each_possible_cpu(cpu) {
1091 if (head_page(tr->data[cpu])) {
1092 total += tr->data[cpu]->trace_idx;
1093 if (tr->data[cpu]->trace_idx > tr->entries)
1094 entries += tr->entries;
1096 entries += tr->data[cpu]->trace_idx;
1100 seq_printf(m, "%s latency trace v1.1.5 on %s\n",
1102 seq_puts(m, "-----------------------------------"
1103 "---------------------------------\n");
1104 seq_printf(m, " latency: %lu us, #%lu/%lu, CPU#%d |"
1105 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1106 nsecs_to_usecs(data->saved_latency),
1110 #if defined(CONFIG_PREEMPT_NONE)
1112 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1114 #elif defined(CONFIG_PREEMPT_DESKTOP)
1119 /* These are reserved for later use */
1122 seq_printf(m, " #P:%d)\n", num_online_cpus());
1126 seq_puts(m, " -----------------\n");
1127 seq_printf(m, " | task: %.16s-%d "
1128 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1129 data->comm, data->pid, data->uid, data->nice,
1130 data->policy, data->rt_priority);
1131 seq_puts(m, " -----------------\n");
1133 if (data->critical_start) {
1134 seq_puts(m, " => started at: ");
1135 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
1136 trace_print_seq(m, &iter->seq);
1137 seq_puts(m, "\n => ended at: ");
1138 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
1139 trace_print_seq(m, &iter->seq);
1147 lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
1149 int hardirq, softirq;
1152 comm = trace_find_cmdline(entry->pid);
1154 trace_seq_printf(s, "%8.8s-%-5d ", comm, entry->pid);
1155 trace_seq_printf(s, "%d", cpu);
1156 trace_seq_printf(s, "%c%c",
1157 (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' : '.',
1158 ((entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.'));
1160 hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
1161 softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
1162 if (hardirq && softirq)
1163 trace_seq_putc(s, 'H');
1166 trace_seq_putc(s, 'h');
1169 trace_seq_putc(s, 's');
1171 trace_seq_putc(s, '.');
1175 if (entry->preempt_count)
1176 trace_seq_printf(s, "%x", entry->preempt_count);
1178 trace_seq_puts(s, ".");
1181 unsigned long preempt_mark_thresh = 100;
1184 lat_print_timestamp(struct trace_seq *s, unsigned long long abs_usecs,
1185 unsigned long rel_usecs)
1187 trace_seq_printf(s, " %4lldus", abs_usecs);
1188 if (rel_usecs > preempt_mark_thresh)
1189 trace_seq_puts(s, "!: ");
1190 else if (rel_usecs > 1)
1191 trace_seq_puts(s, "+: ");
1193 trace_seq_puts(s, " : ");
1196 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
1199 print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
1201 struct trace_seq *s = &iter->seq;
1202 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1203 struct trace_entry *next_entry = find_next_entry(iter, NULL);
1204 unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
1205 struct trace_entry *entry = iter->ent;
1206 unsigned long abs_usecs;
1207 unsigned long rel_usecs;
1215 rel_usecs = ns2usecs(next_entry->t - entry->t);
1216 abs_usecs = ns2usecs(entry->t - iter->tr->time_start);
1219 comm = trace_find_cmdline(entry->pid);
1220 trace_seq_printf(s, "%16s %5d %d %d %08x %08x [%08lx]"
1221 " %ld.%03ldms (+%ld.%03ldms): ",
1223 entry->pid, cpu, entry->flags,
1224 entry->preempt_count, trace_idx,
1227 abs_usecs % 1000, rel_usecs/1000,
1230 lat_print_generic(s, entry, cpu);
1231 lat_print_timestamp(s, abs_usecs, rel_usecs);
1233 switch (entry->type) {
1235 seq_print_ip_sym(s, entry->fn.ip, sym_flags);
1236 trace_seq_puts(s, " (");
1237 seq_print_ip_sym(s, entry->fn.parent_ip, sym_flags);
1238 trace_seq_puts(s, ")\n");
1242 T = entry->ctx.next_state < sizeof(state_to_char) ?
1243 state_to_char[entry->ctx.next_state] : 'X';
1245 state = entry->ctx.prev_state ? __ffs(entry->ctx.prev_state) + 1 : 0;
1246 S = state < sizeof(state_to_char) - 1 ? state_to_char[state] : 'X';
1247 comm = trace_find_cmdline(entry->ctx.next_pid);
1248 trace_seq_printf(s, " %5d:%3d:%c %s %5d:%3d:%c %s\n",
1249 entry->ctx.prev_pid,
1250 entry->ctx.prev_prio,
1251 S, entry->type == TRACE_CTX ? "==>" : " +",
1252 entry->ctx.next_pid,
1253 entry->ctx.next_prio,
1257 trace_seq_printf(s, "# %ld %ld %ld\n",
1258 entry->special.arg1,
1259 entry->special.arg2,
1260 entry->special.arg3);
1263 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1265 trace_seq_puts(s, " <= ");
1266 seq_print_ip_sym(s, entry->stack.caller[i], sym_flags);
1268 trace_seq_puts(s, "\n");
1271 trace_seq_printf(s, "Unknown type %d\n", entry->type);
1276 static int print_trace_fmt(struct trace_iterator *iter)
1278 struct trace_seq *s = &iter->seq;
1279 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1280 struct trace_entry *entry;
1281 unsigned long usec_rem;
1282 unsigned long long t;
1291 comm = trace_find_cmdline(iter->ent->pid);
1293 t = ns2usecs(entry->t);
1294 usec_rem = do_div(t, 1000000ULL);
1295 secs = (unsigned long)t;
1297 ret = trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid);
1300 ret = trace_seq_printf(s, "[%02d] ", iter->cpu);
1303 ret = trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem);
1307 switch (entry->type) {
1309 ret = seq_print_ip_sym(s, entry->fn.ip, sym_flags);
1312 if ((sym_flags & TRACE_ITER_PRINT_PARENT) &&
1313 entry->fn.parent_ip) {
1314 ret = trace_seq_printf(s, " <-");
1317 ret = seq_print_ip_sym(s, entry->fn.parent_ip,
1322 ret = trace_seq_printf(s, "\n");
1328 S = entry->ctx.prev_state < sizeof(state_to_char) ?
1329 state_to_char[entry->ctx.prev_state] : 'X';
1330 T = entry->ctx.next_state < sizeof(state_to_char) ?
1331 state_to_char[entry->ctx.next_state] : 'X';
1332 ret = trace_seq_printf(s, " %5d:%3d:%c %s %5d:%3d:%c\n",
1333 entry->ctx.prev_pid,
1334 entry->ctx.prev_prio,
1336 entry->type == TRACE_CTX ? "==>" : " +",
1337 entry->ctx.next_pid,
1338 entry->ctx.next_prio,
1344 ret = trace_seq_printf(s, "# %ld %ld %ld\n",
1345 entry->special.arg1,
1346 entry->special.arg2,
1347 entry->special.arg3);
1352 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1354 ret = trace_seq_puts(s, " <= ");
1358 ret = seq_print_ip_sym(s, entry->stack.caller[i],
1363 ret = trace_seq_puts(s, "\n");
1371 static int print_raw_fmt(struct trace_iterator *iter)
1373 struct trace_seq *s = &iter->seq;
1374 struct trace_entry *entry;
1380 ret = trace_seq_printf(s, "%d %d %llu ",
1381 entry->pid, iter->cpu, entry->t);
1385 switch (entry->type) {
1387 ret = trace_seq_printf(s, "%x %x\n",
1388 entry->fn.ip, entry->fn.parent_ip);
1394 S = entry->ctx.prev_state < sizeof(state_to_char) ?
1395 state_to_char[entry->ctx.prev_state] : 'X';
1396 T = entry->ctx.next_state < sizeof(state_to_char) ?
1397 state_to_char[entry->ctx.next_state] : 'X';
1398 if (entry->type == TRACE_WAKE)
1400 ret = trace_seq_printf(s, "%d %d %c %d %d %c\n",
1401 entry->ctx.prev_pid,
1402 entry->ctx.prev_prio,
1404 entry->ctx.next_pid,
1405 entry->ctx.next_prio,
1412 ret = trace_seq_printf(s, "# %ld %ld %ld\n",
1413 entry->special.arg1,
1414 entry->special.arg2,
1415 entry->special.arg3);
1423 #define SEQ_PUT_FIELD_RET(s, x) \
1425 if (!trace_seq_putmem(s, &(x), sizeof(x))) \
1429 #define SEQ_PUT_HEX_FIELD_RET(s, x) \
1431 if (!trace_seq_putmem_hex(s, &(x), sizeof(x))) \
1435 static int print_hex_fmt(struct trace_iterator *iter)
1437 struct trace_seq *s = &iter->seq;
1438 unsigned char newline = '\n';
1439 struct trace_entry *entry;
1444 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
1445 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
1446 SEQ_PUT_HEX_FIELD_RET(s, entry->t);
1448 switch (entry->type) {
1450 SEQ_PUT_HEX_FIELD_RET(s, entry->fn.ip);
1451 SEQ_PUT_HEX_FIELD_RET(s, entry->fn.parent_ip);
1455 S = entry->ctx.prev_state < sizeof(state_to_char) ?
1456 state_to_char[entry->ctx.prev_state] : 'X';
1457 T = entry->ctx.next_state < sizeof(state_to_char) ?
1458 state_to_char[entry->ctx.next_state] : 'X';
1459 if (entry->type == TRACE_WAKE)
1461 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.prev_pid);
1462 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.prev_prio);
1463 SEQ_PUT_HEX_FIELD_RET(s, S);
1464 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.next_pid);
1465 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.next_prio);
1466 SEQ_PUT_HEX_FIELD_RET(s, entry->fn.parent_ip);
1467 SEQ_PUT_HEX_FIELD_RET(s, T);
1471 SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg1);
1472 SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg2);
1473 SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg3);
1476 SEQ_PUT_FIELD_RET(s, newline);
1481 static int print_bin_fmt(struct trace_iterator *iter)
1483 struct trace_seq *s = &iter->seq;
1484 struct trace_entry *entry;
1488 SEQ_PUT_FIELD_RET(s, entry->pid);
1489 SEQ_PUT_FIELD_RET(s, entry->cpu);
1490 SEQ_PUT_FIELD_RET(s, entry->t);
1492 switch (entry->type) {
1494 SEQ_PUT_FIELD_RET(s, entry->fn.ip);
1495 SEQ_PUT_FIELD_RET(s, entry->fn.parent_ip);
1498 SEQ_PUT_FIELD_RET(s, entry->ctx.prev_pid);
1499 SEQ_PUT_FIELD_RET(s, entry->ctx.prev_prio);
1500 SEQ_PUT_FIELD_RET(s, entry->ctx.prev_state);
1501 SEQ_PUT_FIELD_RET(s, entry->ctx.next_pid);
1502 SEQ_PUT_FIELD_RET(s, entry->ctx.next_prio);
1503 SEQ_PUT_FIELD_RET(s, entry->ctx.next_state);
1507 SEQ_PUT_FIELD_RET(s, entry->special.arg1);
1508 SEQ_PUT_FIELD_RET(s, entry->special.arg2);
1509 SEQ_PUT_FIELD_RET(s, entry->special.arg3);
1515 static int trace_empty(struct trace_iterator *iter)
1517 struct trace_array_cpu *data;
1520 for_each_possible_cpu(cpu) {
1521 data = iter->tr->data[cpu];
1523 if (head_page(data) && data->trace_idx &&
1524 (data->trace_tail != data->trace_head ||
1525 data->trace_tail_idx != data->trace_head_idx))
1531 static int print_trace_line(struct trace_iterator *iter)
1533 if (iter->trace && iter->trace->print_line)
1534 return iter->trace->print_line(iter);
1536 if (trace_flags & TRACE_ITER_BIN)
1537 return print_bin_fmt(iter);
1539 if (trace_flags & TRACE_ITER_HEX)
1540 return print_hex_fmt(iter);
1542 if (trace_flags & TRACE_ITER_RAW)
1543 return print_raw_fmt(iter);
1545 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
1546 return print_lat_fmt(iter, iter->idx, iter->cpu);
1548 return print_trace_fmt(iter);
1551 static int s_show(struct seq_file *m, void *v)
1553 struct trace_iterator *iter = v;
1555 if (iter->ent == NULL) {
1557 seq_printf(m, "# tracer: %s\n", iter->trace->name);
1560 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1561 /* print nothing if the buffers are empty */
1562 if (trace_empty(iter))
1564 print_trace_header(m, iter);
1565 if (!(trace_flags & TRACE_ITER_VERBOSE))
1566 print_lat_help_header(m);
1568 if (!(trace_flags & TRACE_ITER_VERBOSE))
1569 print_func_help_header(m);
1572 print_trace_line(iter);
1573 trace_print_seq(m, &iter->seq);
1579 static struct seq_operations tracer_seq_ops = {
1586 static struct trace_iterator *
1587 __tracing_open(struct inode *inode, struct file *file, int *ret)
1589 struct trace_iterator *iter;
1591 if (tracing_disabled) {
1596 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1602 mutex_lock(&trace_types_lock);
1603 if (current_trace && current_trace->print_max)
1606 iter->tr = inode->i_private;
1607 iter->trace = current_trace;
1610 /* TODO stop tracer */
1611 *ret = seq_open(file, &tracer_seq_ops);
1613 struct seq_file *m = file->private_data;
1616 /* stop the trace while dumping */
1620 if (iter->trace && iter->trace->open)
1621 iter->trace->open(iter);
1626 mutex_unlock(&trace_types_lock);
1632 int tracing_open_generic(struct inode *inode, struct file *filp)
1634 if (tracing_disabled)
1637 filp->private_data = inode->i_private;
1641 int tracing_release(struct inode *inode, struct file *file)
1643 struct seq_file *m = (struct seq_file *)file->private_data;
1644 struct trace_iterator *iter = m->private;
1646 mutex_lock(&trace_types_lock);
1647 if (iter->trace && iter->trace->close)
1648 iter->trace->close(iter);
1650 /* reenable tracing if it was previously enabled */
1653 mutex_unlock(&trace_types_lock);
1655 seq_release(inode, file);
1660 static int tracing_open(struct inode *inode, struct file *file)
1664 __tracing_open(inode, file, &ret);
1669 static int tracing_lt_open(struct inode *inode, struct file *file)
1671 struct trace_iterator *iter;
1674 iter = __tracing_open(inode, file, &ret);
1677 iter->iter_flags |= TRACE_FILE_LAT_FMT;
1684 t_next(struct seq_file *m, void *v, loff_t *pos)
1686 struct tracer *t = m->private;
1698 static void *t_start(struct seq_file *m, loff_t *pos)
1700 struct tracer *t = m->private;
1703 mutex_lock(&trace_types_lock);
1704 for (; t && l < *pos; t = t_next(m, t, &l))
1710 static void t_stop(struct seq_file *m, void *p)
1712 mutex_unlock(&trace_types_lock);
1715 static int t_show(struct seq_file *m, void *v)
1717 struct tracer *t = v;
1722 seq_printf(m, "%s", t->name);
1731 static struct seq_operations show_traces_seq_ops = {
1738 static int show_traces_open(struct inode *inode, struct file *file)
1742 if (tracing_disabled)
1745 ret = seq_open(file, &show_traces_seq_ops);
1747 struct seq_file *m = file->private_data;
1748 m->private = trace_types;
1754 static struct file_operations tracing_fops = {
1755 .open = tracing_open,
1757 .llseek = seq_lseek,
1758 .release = tracing_release,
1761 static struct file_operations tracing_lt_fops = {
1762 .open = tracing_lt_open,
1764 .llseek = seq_lseek,
1765 .release = tracing_release,
1768 static struct file_operations show_traces_fops = {
1769 .open = show_traces_open,
1771 .release = seq_release,
1775 * Only trace on a CPU if the bitmask is set:
1777 static cpumask_t tracing_cpumask = CPU_MASK_ALL;
1780 * When tracing/tracing_cpu_mask is modified then this holds
1781 * the new bitmask we are about to install:
1783 static cpumask_t tracing_cpumask_new;
1786 * The tracer itself will not take this lock, but still we want
1787 * to provide a consistent cpumask to user-space:
1789 static DEFINE_MUTEX(tracing_cpumask_update_lock);
1792 * Temporary storage for the character representation of the
1793 * CPU bitmask (and one more byte for the newline):
1795 static char mask_str[NR_CPUS + 1];
1798 tracing_cpumask_read(struct file *filp, char __user *ubuf,
1799 size_t count, loff_t *ppos)
1803 mutex_lock(&tracing_cpumask_update_lock);
1805 len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
1806 if (count - len < 2) {
1810 len += sprintf(mask_str + len, "\n");
1811 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
1814 mutex_unlock(&tracing_cpumask_update_lock);
1820 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
1821 size_t count, loff_t *ppos)
1825 mutex_lock(&tracing_cpumask_update_lock);
1826 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
1830 raw_local_irq_disable();
1831 __raw_spin_lock(&ftrace_max_lock);
1832 for_each_possible_cpu(cpu) {
1834 * Increase/decrease the disabled counter if we are
1835 * about to flip a bit in the cpumask:
1837 if (cpu_isset(cpu, tracing_cpumask) &&
1838 !cpu_isset(cpu, tracing_cpumask_new)) {
1839 atomic_inc(&global_trace.data[cpu]->disabled);
1841 if (!cpu_isset(cpu, tracing_cpumask) &&
1842 cpu_isset(cpu, tracing_cpumask_new)) {
1843 atomic_dec(&global_trace.data[cpu]->disabled);
1846 __raw_spin_unlock(&ftrace_max_lock);
1847 raw_local_irq_enable();
1849 tracing_cpumask = tracing_cpumask_new;
1851 mutex_unlock(&tracing_cpumask_update_lock);
1856 mutex_unlock(&tracing_cpumask_update_lock);
1861 static struct file_operations tracing_cpumask_fops = {
1862 .open = tracing_open_generic,
1863 .read = tracing_cpumask_read,
1864 .write = tracing_cpumask_write,
1868 tracing_iter_ctrl_read(struct file *filp, char __user *ubuf,
1869 size_t cnt, loff_t *ppos)
1876 /* calulate max size */
1877 for (i = 0; trace_options[i]; i++) {
1878 len += strlen(trace_options[i]);
1879 len += 3; /* "no" and space */
1882 /* +2 for \n and \0 */
1883 buf = kmalloc(len + 2, GFP_KERNEL);
1887 for (i = 0; trace_options[i]; i++) {
1888 if (trace_flags & (1 << i))
1889 r += sprintf(buf + r, "%s ", trace_options[i]);
1891 r += sprintf(buf + r, "no%s ", trace_options[i]);
1894 r += sprintf(buf + r, "\n");
1895 WARN_ON(r >= len + 2);
1897 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1905 tracing_iter_ctrl_write(struct file *filp, const char __user *ubuf,
1906 size_t cnt, loff_t *ppos)
1916 if (copy_from_user(&buf, ubuf, cnt))
1921 if (strncmp(buf, "no", 2) == 0) {
1926 for (i = 0; trace_options[i]; i++) {
1927 int len = strlen(trace_options[i]);
1929 if (strncmp(cmp, trace_options[i], len) == 0) {
1931 trace_flags &= ~(1 << i);
1933 trace_flags |= (1 << i);
1938 * If no option could be set, return an error:
1940 if (!trace_options[i])
1948 static struct file_operations tracing_iter_fops = {
1949 .open = tracing_open_generic,
1950 .read = tracing_iter_ctrl_read,
1951 .write = tracing_iter_ctrl_write,
1954 static const char readme_msg[] =
1955 "tracing mini-HOWTO:\n\n"
1957 "# mount -t debugfs nodev /debug\n\n"
1958 "# cat /debug/tracing/available_tracers\n"
1959 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
1960 "# cat /debug/tracing/current_tracer\n"
1962 "# echo sched_switch > /debug/tracing/current_tracer\n"
1963 "# cat /debug/tracing/current_tracer\n"
1965 "# cat /debug/tracing/iter_ctrl\n"
1966 "noprint-parent nosym-offset nosym-addr noverbose\n"
1967 "# echo print-parent > /debug/tracing/iter_ctrl\n"
1968 "# echo 1 > /debug/tracing/tracing_enabled\n"
1969 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
1970 "echo 0 > /debug/tracing/tracing_enabled\n"
1974 tracing_readme_read(struct file *filp, char __user *ubuf,
1975 size_t cnt, loff_t *ppos)
1977 return simple_read_from_buffer(ubuf, cnt, ppos,
1978 readme_msg, strlen(readme_msg));
1981 static struct file_operations tracing_readme_fops = {
1982 .open = tracing_open_generic,
1983 .read = tracing_readme_read,
1987 tracing_ctrl_read(struct file *filp, char __user *ubuf,
1988 size_t cnt, loff_t *ppos)
1990 struct trace_array *tr = filp->private_data;
1994 r = sprintf(buf, "%ld\n", tr->ctrl);
1995 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1999 tracing_ctrl_write(struct file *filp, const char __user *ubuf,
2000 size_t cnt, loff_t *ppos)
2002 struct trace_array *tr = filp->private_data;
2009 if (copy_from_user(&buf, ubuf, cnt))
2014 val = simple_strtoul(buf, NULL, 10);
2018 mutex_lock(&trace_types_lock);
2019 if (tr->ctrl ^ val) {
2027 if (current_trace && current_trace->ctrl_update)
2028 current_trace->ctrl_update(tr);
2030 mutex_unlock(&trace_types_lock);
2038 tracing_set_trace_read(struct file *filp, char __user *ubuf,
2039 size_t cnt, loff_t *ppos)
2041 char buf[max_tracer_type_len+2];
2044 mutex_lock(&trace_types_lock);
2046 r = sprintf(buf, "%s\n", current_trace->name);
2048 r = sprintf(buf, "\n");
2049 mutex_unlock(&trace_types_lock);
2051 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2055 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
2056 size_t cnt, loff_t *ppos)
2058 struct trace_array *tr = &global_trace;
2060 char buf[max_tracer_type_len+1];
2063 if (cnt > max_tracer_type_len)
2064 cnt = max_tracer_type_len;
2066 if (copy_from_user(&buf, ubuf, cnt))
2071 /* strip ending whitespace. */
2072 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
2075 mutex_lock(&trace_types_lock);
2076 for (t = trace_types; t; t = t->next) {
2077 if (strcmp(t->name, buf) == 0)
2080 if (!t || t == current_trace)
2083 if (current_trace && current_trace->reset)
2084 current_trace->reset(tr);
2091 mutex_unlock(&trace_types_lock);
2099 tracing_max_lat_read(struct file *filp, char __user *ubuf,
2100 size_t cnt, loff_t *ppos)
2102 unsigned long *ptr = filp->private_data;
2106 r = snprintf(buf, 64, "%ld\n",
2107 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
2110 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2114 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
2115 size_t cnt, loff_t *ppos)
2117 long *ptr = filp->private_data;
2124 if (copy_from_user(&buf, ubuf, cnt))
2129 val = simple_strtoul(buf, NULL, 10);
2136 static atomic_t tracing_reader;
2138 static int tracing_open_pipe(struct inode *inode, struct file *filp)
2140 struct trace_iterator *iter;
2142 if (tracing_disabled)
2145 /* We only allow for reader of the pipe */
2146 if (atomic_inc_return(&tracing_reader) != 1) {
2147 atomic_dec(&tracing_reader);
2151 /* create a buffer to store the information to pass to userspace */
2152 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2156 iter->tr = &global_trace;
2157 iter->trace = current_trace;
2159 filp->private_data = iter;
2164 static int tracing_release_pipe(struct inode *inode, struct file *file)
2166 struct trace_iterator *iter = file->private_data;
2169 atomic_dec(&tracing_reader);
2175 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
2177 struct trace_iterator *iter = filp->private_data;
2179 if (trace_flags & TRACE_ITER_BLOCK) {
2181 * Always select as readable when in blocking mode
2183 return POLLIN | POLLRDNORM;
2186 if (!trace_empty(iter))
2187 return POLLIN | POLLRDNORM;
2188 poll_wait(filp, &trace_wait, poll_table);
2189 if (!trace_empty(iter))
2190 return POLLIN | POLLRDNORM;
2200 tracing_read_pipe(struct file *filp, char __user *ubuf,
2201 size_t cnt, loff_t *ppos)
2203 struct trace_iterator *iter = filp->private_data;
2204 struct trace_array_cpu *data;
2205 struct trace_array *tr = iter->tr;
2206 struct tracer *tracer = iter->trace;
2207 static cpumask_t mask;
2209 unsigned long flags;
2210 #ifdef CONFIG_FTRACE
2218 /* return any leftover data */
2219 if (iter->seq.len > start) {
2220 len = iter->seq.len - start;
2223 ret = copy_to_user(ubuf, iter->seq.buffer + start, cnt);
2232 trace_seq_reset(&iter->seq);
2235 while (trace_empty(iter)) {
2237 * This is a make-shift waitqueue. The reason we don't use
2238 * an actual wait queue is because:
2239 * 1) we only ever have one waiter
2240 * 2) the tracing, traces all functions, we don't want
2241 * the overhead of calling wake_up and friends
2242 * (and tracing them too)
2243 * Anyway, this is really very primitive wakeup.
2245 set_current_state(TASK_INTERRUPTIBLE);
2246 iter->tr->waiter = current;
2248 /* sleep for one second, and try again. */
2249 schedule_timeout(HZ);
2251 iter->tr->waiter = NULL;
2253 if (signal_pending(current))
2256 if (iter->trace != current_trace)
2260 * We block until we read something and tracing is disabled.
2261 * We still block if tracing is disabled, but we have never
2262 * read anything. This allows a user to cat this file, and
2263 * then enable tracing. But after we have read something,
2264 * we give an EOF when tracing is again disabled.
2266 * iter->pos will be 0 if we haven't read anything.
2268 if (!tracer_enabled && iter->pos)
2274 /* stop when tracing is finished */
2275 if (trace_empty(iter))
2278 if (cnt >= PAGE_SIZE)
2279 cnt = PAGE_SIZE - 1;
2281 memset(iter, 0, sizeof(*iter));
2283 iter->trace = tracer;
2287 * We need to stop all tracing on all CPUS to read the
2288 * the next buffer. This is a bit expensive, but is
2289 * not done often. We fill all what we can read,
2290 * and then release the locks again.
2294 local_irq_save(flags);
2295 #ifdef CONFIG_FTRACE
2296 ftrace_save = ftrace_enabled;
2300 for_each_possible_cpu(cpu) {
2301 data = iter->tr->data[cpu];
2303 if (!head_page(data) || !data->trace_idx)
2306 atomic_inc(&data->disabled);
2310 for_each_cpu_mask(cpu, mask) {
2311 data = iter->tr->data[cpu];
2312 __raw_spin_lock(&data->lock);
2315 while (find_next_entry_inc(iter) != NULL) {
2316 int len = iter->seq.len;
2318 ret = print_trace_line(iter);
2320 /* don't print partial lines */
2321 iter->seq.len = len;
2325 trace_consume(iter);
2327 if (iter->seq.len >= cnt)
2331 for_each_cpu_mask(cpu, mask) {
2332 data = iter->tr->data[cpu];
2333 __raw_spin_unlock(&data->lock);
2336 for_each_cpu_mask(cpu, mask) {
2337 data = iter->tr->data[cpu];
2338 atomic_dec(&data->disabled);
2340 #ifdef CONFIG_FTRACE
2341 ftrace_enabled = ftrace_save;
2343 local_irq_restore(flags);
2345 /* Now copy what we have to the user */
2346 read = iter->seq.len;
2350 ret = copy_to_user(ubuf, iter->seq.buffer, read);
2352 if (read < iter->seq.len)
2355 trace_seq_reset(&iter->seq);
2363 static struct file_operations tracing_max_lat_fops = {
2364 .open = tracing_open_generic,
2365 .read = tracing_max_lat_read,
2366 .write = tracing_max_lat_write,
2369 static struct file_operations tracing_ctrl_fops = {
2370 .open = tracing_open_generic,
2371 .read = tracing_ctrl_read,
2372 .write = tracing_ctrl_write,
2375 static struct file_operations set_tracer_fops = {
2376 .open = tracing_open_generic,
2377 .read = tracing_set_trace_read,
2378 .write = tracing_set_trace_write,
2381 static struct file_operations tracing_pipe_fops = {
2382 .open = tracing_open_pipe,
2383 .poll = tracing_poll_pipe,
2384 .read = tracing_read_pipe,
2385 .release = tracing_release_pipe,
2388 #ifdef CONFIG_DYNAMIC_FTRACE
2391 tracing_read_long(struct file *filp, char __user *ubuf,
2392 size_t cnt, loff_t *ppos)
2394 unsigned long *p = filp->private_data;
2398 r = sprintf(buf, "%ld\n", *p);
2400 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2403 static struct file_operations tracing_read_long_fops = {
2404 .open = tracing_open_generic,
2405 .read = tracing_read_long,
2409 static struct dentry *d_tracer;
2411 struct dentry *tracing_init_dentry(void)
2418 d_tracer = debugfs_create_dir("tracing", NULL);
2420 if (!d_tracer && !once) {
2422 pr_warning("Could not create debugfs directory 'tracing'\n");
2429 #ifdef CONFIG_FTRACE_SELFTEST
2430 /* Let selftest have access to static functions in this file */
2431 #include "trace_selftest.c"
2434 static __init void tracer_init_debugfs(void)
2436 struct dentry *d_tracer;
2437 struct dentry *entry;
2439 d_tracer = tracing_init_dentry();
2441 entry = debugfs_create_file("tracing_enabled", 0644, d_tracer,
2442 &global_trace, &tracing_ctrl_fops);
2444 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
2446 entry = debugfs_create_file("iter_ctrl", 0644, d_tracer,
2447 NULL, &tracing_iter_fops);
2449 pr_warning("Could not create debugfs 'iter_ctrl' entry\n");
2451 entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer,
2452 NULL, &tracing_cpumask_fops);
2454 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
2456 entry = debugfs_create_file("latency_trace", 0444, d_tracer,
2457 &global_trace, &tracing_lt_fops);
2459 pr_warning("Could not create debugfs 'latency_trace' entry\n");
2461 entry = debugfs_create_file("trace", 0444, d_tracer,
2462 &global_trace, &tracing_fops);
2464 pr_warning("Could not create debugfs 'trace' entry\n");
2466 entry = debugfs_create_file("available_tracers", 0444, d_tracer,
2467 &global_trace, &show_traces_fops);
2469 pr_warning("Could not create debugfs 'trace' entry\n");
2471 entry = debugfs_create_file("current_tracer", 0444, d_tracer,
2472 &global_trace, &set_tracer_fops);
2474 pr_warning("Could not create debugfs 'trace' entry\n");
2476 entry = debugfs_create_file("tracing_max_latency", 0644, d_tracer,
2477 &tracing_max_latency,
2478 &tracing_max_lat_fops);
2480 pr_warning("Could not create debugfs "
2481 "'tracing_max_latency' entry\n");
2483 entry = debugfs_create_file("tracing_thresh", 0644, d_tracer,
2484 &tracing_thresh, &tracing_max_lat_fops);
2486 pr_warning("Could not create debugfs "
2487 "'tracing_threash' entry\n");
2488 entry = debugfs_create_file("README", 0644, d_tracer,
2489 NULL, &tracing_readme_fops);
2491 pr_warning("Could not create debugfs 'README' entry\n");
2493 entry = debugfs_create_file("trace_pipe", 0644, d_tracer,
2494 NULL, &tracing_pipe_fops);
2496 pr_warning("Could not create debugfs "
2497 "'tracing_threash' entry\n");
2499 #ifdef CONFIG_DYNAMIC_FTRACE
2500 entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
2501 &ftrace_update_tot_cnt,
2502 &tracing_read_long_fops);
2504 pr_warning("Could not create debugfs "
2505 "'dyn_ftrace_total_info' entry\n");
2509 /* dummy trace to disable tracing */
2510 static struct tracer no_tracer __read_mostly =
2515 static int trace_alloc_page(void)
2517 struct trace_array_cpu *data;
2518 struct page *page, *tmp;
2523 /* first allocate a page for each CPU */
2524 for_each_possible_cpu(i) {
2525 array = (void *)__get_free_page(GFP_KERNEL);
2526 if (array == NULL) {
2527 printk(KERN_ERR "tracer: failed to allocate page"
2528 "for trace buffer!\n");
2532 page = virt_to_page(array);
2533 list_add(&page->lru, &pages);
2535 /* Only allocate if we are actually using the max trace */
2536 #ifdef CONFIG_TRACER_MAX_TRACE
2537 array = (void *)__get_free_page(GFP_KERNEL);
2538 if (array == NULL) {
2539 printk(KERN_ERR "tracer: failed to allocate page"
2540 "for trace buffer!\n");
2543 page = virt_to_page(array);
2544 list_add(&page->lru, &pages);
2548 /* Now that we successfully allocate a page per CPU, add them */
2549 for_each_possible_cpu(i) {
2550 data = global_trace.data[i];
2551 data->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
2552 page = list_entry(pages.next, struct page, lru);
2553 list_del_init(&page->lru);
2554 list_add_tail(&page->lru, &data->trace_pages);
2557 #ifdef CONFIG_TRACER_MAX_TRACE
2558 data = max_tr.data[i];
2559 data->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
2560 page = list_entry(pages.next, struct page, lru);
2561 list_del_init(&page->lru);
2562 list_add_tail(&page->lru, &data->trace_pages);
2566 global_trace.entries += ENTRIES_PER_PAGE;
2571 list_for_each_entry_safe(page, tmp, &pages, lru) {
2572 list_del_init(&page->lru);
2578 __init static int tracer_alloc_buffers(void)
2580 struct trace_array_cpu *data;
2587 global_trace.ctrl = tracer_enabled;
2589 /* Allocate the first page for all buffers */
2590 for_each_possible_cpu(i) {
2591 data = global_trace.data[i] = &per_cpu(global_trace_cpu, i);
2592 max_tr.data[i] = &per_cpu(max_data, i);
2594 array = (void *)__get_free_page(GFP_KERNEL);
2595 if (array == NULL) {
2596 printk(KERN_ERR "tracer: failed to allocate page"
2597 "for trace buffer!\n");
2601 /* set the array to the list */
2602 INIT_LIST_HEAD(&data->trace_pages);
2603 page = virt_to_page(array);
2604 list_add(&page->lru, &data->trace_pages);
2605 /* use the LRU flag to differentiate the two buffers */
2608 /* Only allocate if we are actually using the max trace */
2609 #ifdef CONFIG_TRACER_MAX_TRACE
2610 array = (void *)__get_free_page(GFP_KERNEL);
2611 if (array == NULL) {
2612 printk(KERN_ERR "tracer: failed to allocate page"
2613 "for trace buffer!\n");
2617 INIT_LIST_HEAD(&max_tr.data[i]->trace_pages);
2618 page = virt_to_page(array);
2619 list_add(&page->lru, &max_tr.data[i]->trace_pages);
2625 * Since we allocate by orders of pages, we may be able to
2628 global_trace.entries = ENTRIES_PER_PAGE;
2631 while (global_trace.entries < trace_nr_entries) {
2632 if (trace_alloc_page())
2636 max_tr.entries = global_trace.entries;
2638 pr_info("tracer: %d pages allocated for %ld",
2639 pages, trace_nr_entries);
2640 pr_info(" entries of %ld bytes\n", (long)TRACE_ENTRY_SIZE);
2641 pr_info(" actual entries %ld\n", global_trace.entries);
2643 tracer_init_debugfs();
2645 trace_init_cmdlines();
2647 register_tracer(&no_tracer);
2648 current_trace = &no_tracer;
2650 /* All seems OK, enable tracing */
2651 tracing_disabled = 0;
2656 for (i-- ; i >= 0; i--) {
2657 struct page *page, *tmp;
2658 struct trace_array_cpu *data = global_trace.data[i];
2661 list_for_each_entry_safe(page, tmp,
2662 &data->trace_pages, lru) {
2663 list_del_init(&page->lru);
2668 #ifdef CONFIG_TRACER_MAX_TRACE
2669 data = max_tr.data[i];
2671 list_for_each_entry_safe(page, tmp,
2672 &data->trace_pages, lru) {
2673 list_del_init(&page->lru);
2681 fs_initcall(tracer_alloc_buffers);