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 unsigned long __read_mostly tracing_nr_buffers;
39 static cpumask_t __read_mostly tracing_buffer_mask;
41 #define for_each_tracing_cpu(cpu) \
42 for_each_cpu_mask(cpu, tracing_buffer_mask)
44 /* dummy trace to disable tracing */
45 static struct tracer no_tracer __read_mostly = {
49 static int trace_alloc_page(void);
50 static int trace_free_page(void);
52 static int tracing_disabled = 1;
55 ns2usecs(cycle_t nsec)
62 cycle_t ftrace_now(int cpu)
64 return cpu_clock(cpu);
68 * The global_trace is the descriptor that holds the tracing
69 * buffers for the live tracing. For each CPU, it contains
70 * a link list of pages that will store trace entries. The
71 * page descriptor of the pages in the memory is used to hold
72 * the link list by linking the lru item in the page descriptor
73 * to each of the pages in the buffer per CPU.
75 * For each active CPU there is a data field that holds the
76 * pages for the buffer for that CPU. Each CPU has the same number
77 * of pages allocated for its buffer.
79 static struct trace_array global_trace;
81 static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
84 * The max_tr is used to snapshot the global_trace when a maximum
85 * latency is reached. Some tracers will use this to store a maximum
86 * trace while it continues examining live traces.
88 * The buffers for the max_tr are set up the same as the global_trace.
89 * When a snapshot is taken, the link list of the max_tr is swapped
90 * with the link list of the global_trace and the buffers are reset for
91 * the global_trace so the tracing can continue.
93 static struct trace_array max_tr;
95 static DEFINE_PER_CPU(struct trace_array_cpu, max_data);
97 /* tracer_enabled is used to toggle activation of a tracer */
98 static int tracer_enabled = 1;
101 * trace_nr_entries is the number of entries that is allocated
102 * for a buffer. Note, the number of entries is always rounded
103 * to ENTRIES_PER_PAGE.
105 static unsigned long trace_nr_entries = 65536UL;
107 /* trace_types holds a link list of available tracers. */
108 static struct tracer *trace_types __read_mostly;
110 /* current_trace points to the tracer that is currently active */
111 static struct tracer *current_trace __read_mostly;
114 * max_tracer_type_len is used to simplify the allocating of
115 * buffers to read userspace tracer names. We keep track of
116 * the longest tracer name registered.
118 static int max_tracer_type_len;
121 * trace_types_lock is used to protect the trace_types list.
122 * This lock is also used to keep user access serialized.
123 * Accesses from userspace will grab this lock while userspace
124 * activities happen inside the kernel.
126 static DEFINE_MUTEX(trace_types_lock);
128 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
129 static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
131 /* trace_flags holds iter_ctrl options */
132 unsigned long trace_flags = TRACE_ITER_PRINT_PARENT;
135 * trace_wake_up - wake up tasks waiting for trace input
137 * Simply wakes up any task that is blocked on the trace_wait
138 * queue. These is used with trace_poll for tasks polling the trace.
140 void trace_wake_up(void)
143 * The runqueue_is_locked() can fail, but this is the best we
146 if (!(trace_flags & TRACE_ITER_BLOCK) && !runqueue_is_locked())
147 wake_up(&trace_wait);
150 #define ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(struct trace_entry))
152 static int __init set_nr_entries(char *str)
154 unsigned long nr_entries;
159 ret = strict_strtoul(str, 0, &nr_entries);
160 /* nr_entries can not be zero */
161 if (ret < 0 || nr_entries == 0)
163 trace_nr_entries = nr_entries;
166 __setup("trace_entries=", set_nr_entries);
168 unsigned long nsecs_to_usecs(unsigned long nsecs)
174 * trace_flag_type is an enumeration that holds different
175 * states when a trace occurs. These are:
176 * IRQS_OFF - interrupts were disabled
177 * NEED_RESCED - reschedule is requested
178 * HARDIRQ - inside an interrupt handler
179 * SOFTIRQ - inside a softirq handler
181 enum trace_flag_type {
182 TRACE_FLAG_IRQS_OFF = 0x01,
183 TRACE_FLAG_NEED_RESCHED = 0x02,
184 TRACE_FLAG_HARDIRQ = 0x04,
185 TRACE_FLAG_SOFTIRQ = 0x08,
189 * TRACE_ITER_SYM_MASK masks the options in trace_flags that
190 * control the output of kernel symbols.
192 #define TRACE_ITER_SYM_MASK \
193 (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
195 /* These must match the bit postions in trace_iterator_flags */
196 static const char *trace_options[] = {
211 * ftrace_max_lock is used to protect the swapping of buffers
212 * when taking a max snapshot. The buffers themselves are
213 * protected by per_cpu spinlocks. But the action of the swap
214 * needs its own lock.
216 * This is defined as a raw_spinlock_t in order to help
217 * with performance when lockdep debugging is enabled.
219 static raw_spinlock_t ftrace_max_lock =
220 (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
223 * Copy the new maximum trace into the separate maximum-trace
224 * structure. (this way the maximum trace is permanently saved,
225 * for later retrieval via /debugfs/tracing/latency_trace)
228 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
230 struct trace_array_cpu *data = tr->data[cpu];
233 max_tr.time_start = data->preempt_timestamp;
235 data = max_tr.data[cpu];
236 data->saved_latency = tracing_max_latency;
238 memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
239 data->pid = tsk->pid;
240 data->uid = tsk->uid;
241 data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
242 data->policy = tsk->policy;
243 data->rt_priority = tsk->rt_priority;
245 /* record this tasks comm */
246 tracing_record_cmdline(current);
250 * check_pages - integrity check of trace buffers
252 * As a safty measure we check to make sure the data pages have not
253 * been corrupted. TODO: configure to disable this because it adds
256 void check_pages(struct trace_array_cpu *data)
258 struct page *page, *tmp;
260 BUG_ON(data->trace_pages.next->prev != &data->trace_pages);
261 BUG_ON(data->trace_pages.prev->next != &data->trace_pages);
263 list_for_each_entry_safe(page, tmp, &data->trace_pages, lru) {
264 BUG_ON(page->lru.next->prev != &page->lru);
265 BUG_ON(page->lru.prev->next != &page->lru);
270 * head_page - page address of the first page in per_cpu buffer.
272 * head_page returns the page address of the first page in
273 * a per_cpu buffer. This also preforms various consistency
274 * checks to make sure the buffer has not been corrupted.
276 void *head_page(struct trace_array_cpu *data)
281 if (list_empty(&data->trace_pages))
284 page = list_entry(data->trace_pages.next, struct page, lru);
285 BUG_ON(&page->lru == &data->trace_pages);
287 return page_address(page);
291 * trace_seq_printf - sequence printing of trace information
292 * @s: trace sequence descriptor
293 * @fmt: printf format string
295 * The tracer may use either sequence operations or its own
296 * copy to user routines. To simplify formating of a trace
297 * trace_seq_printf is used to store strings into a special
298 * buffer (@s). Then the output may be either used by
299 * the sequencer or pulled into another buffer.
302 trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
304 int len = (PAGE_SIZE - 1) - s->len;
312 ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
315 /* If we can't write it all, don't bother writing anything */
325 * trace_seq_puts - trace sequence printing of simple string
326 * @s: trace sequence descriptor
327 * @str: simple string to record
329 * The tracer may use either the sequence operations or its own
330 * copy to user routines. This function records a simple string
331 * into a special buffer (@s) for later retrieval by a sequencer
332 * or other mechanism.
335 trace_seq_puts(struct trace_seq *s, const char *str)
337 int len = strlen(str);
339 if (len > ((PAGE_SIZE - 1) - s->len))
342 memcpy(s->buffer + s->len, str, len);
349 trace_seq_putc(struct trace_seq *s, unsigned char c)
351 if (s->len >= (PAGE_SIZE - 1))
354 s->buffer[s->len++] = c;
360 trace_seq_putmem(struct trace_seq *s, void *mem, size_t len)
362 if (len > ((PAGE_SIZE - 1) - s->len))
365 memcpy(s->buffer + s->len, mem, len);
372 static const char hex2asc[] = "0123456789abcdef";
375 trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len)
377 unsigned char hex[HEX_CHARS];
378 unsigned char *data = mem;
382 BUG_ON(len >= HEX_CHARS);
385 for (i = 0, j = 0; i < len; i++) {
387 for (i = len-1, j = 0; i >= 0; i--) {
391 hex[j++] = hex2asc[byte & 0x0f];
392 hex[j++] = hex2asc[byte >> 4];
396 return trace_seq_putmem(s, hex, j);
400 trace_seq_reset(struct trace_seq *s)
406 trace_print_seq(struct seq_file *m, struct trace_seq *s)
408 int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
411 seq_puts(m, s->buffer);
417 * flip the trace buffers between two trace descriptors.
418 * This usually is the buffers between the global_trace and
419 * the max_tr to record a snapshot of a current trace.
421 * The ftrace_max_lock must be held.
424 flip_trace(struct trace_array_cpu *tr1, struct trace_array_cpu *tr2)
426 struct list_head flip_pages;
428 INIT_LIST_HEAD(&flip_pages);
430 memcpy(&tr1->trace_head_idx, &tr2->trace_head_idx,
431 sizeof(struct trace_array_cpu) -
432 offsetof(struct trace_array_cpu, trace_head_idx));
436 list_splice_init(&tr1->trace_pages, &flip_pages);
437 list_splice_init(&tr2->trace_pages, &tr1->trace_pages);
438 list_splice_init(&flip_pages, &tr2->trace_pages);
439 BUG_ON(!list_empty(&flip_pages));
445 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
447 * @tsk: the task with the latency
448 * @cpu: The cpu that initiated the trace.
450 * Flip the buffers between the @tr and the max_tr and record information
451 * about which task was the cause of this latency.
454 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
456 struct trace_array_cpu *data;
459 WARN_ON_ONCE(!irqs_disabled());
460 __raw_spin_lock(&ftrace_max_lock);
461 /* clear out all the previous traces */
462 for_each_tracing_cpu(i) {
464 flip_trace(max_tr.data[i], data);
468 __update_max_tr(tr, tsk, cpu);
469 __raw_spin_unlock(&ftrace_max_lock);
473 * update_max_tr_single - only copy one trace over, and reset the rest
475 * @tsk - task with the latency
476 * @cpu - the cpu of the buffer to copy.
478 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
481 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
483 struct trace_array_cpu *data = tr->data[cpu];
486 WARN_ON_ONCE(!irqs_disabled());
487 __raw_spin_lock(&ftrace_max_lock);
488 for_each_tracing_cpu(i)
489 tracing_reset(max_tr.data[i]);
491 flip_trace(max_tr.data[cpu], data);
494 __update_max_tr(tr, tsk, cpu);
495 __raw_spin_unlock(&ftrace_max_lock);
499 * register_tracer - register a tracer with the ftrace system.
500 * @type - the plugin for the tracer
502 * Register a new plugin tracer.
504 int register_tracer(struct tracer *type)
511 pr_info("Tracer must have a name\n");
515 mutex_lock(&trace_types_lock);
516 for (t = trace_types; t; t = t->next) {
517 if (strcmp(type->name, t->name) == 0) {
519 pr_info("Trace %s already registered\n",
526 #ifdef CONFIG_FTRACE_STARTUP_TEST
527 if (type->selftest) {
528 struct tracer *saved_tracer = current_trace;
529 struct trace_array_cpu *data;
530 struct trace_array *tr = &global_trace;
531 int saved_ctrl = tr->ctrl;
534 * Run a selftest on this tracer.
535 * Here we reset the trace buffer, and set the current
536 * tracer to be this tracer. The tracer can then run some
537 * internal tracing to verify that everything is in order.
538 * If we fail, we do not register this tracer.
540 for_each_tracing_cpu(i) {
542 if (!head_page(data))
546 current_trace = type;
548 /* the test is responsible for initializing and enabling */
549 pr_info("Testing tracer %s: ", type->name);
550 ret = type->selftest(type, tr);
551 /* the test is responsible for resetting too */
552 current_trace = saved_tracer;
553 tr->ctrl = saved_ctrl;
555 printk(KERN_CONT "FAILED!\n");
558 /* Only reset on passing, to avoid touching corrupted buffers */
559 for_each_tracing_cpu(i) {
561 if (!head_page(data))
565 printk(KERN_CONT "PASSED\n");
569 type->next = trace_types;
571 len = strlen(type->name);
572 if (len > max_tracer_type_len)
573 max_tracer_type_len = len;
576 mutex_unlock(&trace_types_lock);
581 void unregister_tracer(struct tracer *type)
586 mutex_lock(&trace_types_lock);
587 for (t = &trace_types; *t; t = &(*t)->next) {
591 pr_info("Trace %s not registered\n", type->name);
596 if (strlen(type->name) != max_tracer_type_len)
599 max_tracer_type_len = 0;
600 for (t = &trace_types; *t; t = &(*t)->next) {
601 len = strlen((*t)->name);
602 if (len > max_tracer_type_len)
603 max_tracer_type_len = len;
606 mutex_unlock(&trace_types_lock);
609 void tracing_reset(struct trace_array_cpu *data)
613 data->trace_head = data->trace_tail = head_page(data);
614 data->trace_head_idx = 0;
615 data->trace_tail_idx = 0;
618 #define SAVED_CMDLINES 128
619 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
620 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
621 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
622 static int cmdline_idx;
623 static DEFINE_SPINLOCK(trace_cmdline_lock);
625 /* trace in all context switches */
626 atomic_t trace_record_cmdline_enabled __read_mostly;
628 /* temporary disable recording */
629 atomic_t trace_record_cmdline_disabled __read_mostly;
631 static void trace_init_cmdlines(void)
633 memset(&map_pid_to_cmdline, -1, sizeof(map_pid_to_cmdline));
634 memset(&map_cmdline_to_pid, -1, sizeof(map_cmdline_to_pid));
638 void trace_stop_cmdline_recording(void);
640 static void trace_save_cmdline(struct task_struct *tsk)
645 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
649 * It's not the end of the world if we don't get
650 * the lock, but we also don't want to spin
651 * nor do we want to disable interrupts,
652 * so if we miss here, then better luck next time.
654 if (!spin_trylock(&trace_cmdline_lock))
657 idx = map_pid_to_cmdline[tsk->pid];
658 if (idx >= SAVED_CMDLINES) {
659 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
661 map = map_cmdline_to_pid[idx];
662 if (map <= PID_MAX_DEFAULT)
663 map_pid_to_cmdline[map] = (unsigned)-1;
665 map_pid_to_cmdline[tsk->pid] = idx;
670 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
672 spin_unlock(&trace_cmdline_lock);
675 static char *trace_find_cmdline(int pid)
677 char *cmdline = "<...>";
683 if (pid > PID_MAX_DEFAULT)
686 map = map_pid_to_cmdline[pid];
687 if (map >= SAVED_CMDLINES)
690 cmdline = saved_cmdlines[map];
696 void tracing_record_cmdline(struct task_struct *tsk)
698 if (atomic_read(&trace_record_cmdline_disabled))
701 trace_save_cmdline(tsk);
704 static inline struct list_head *
705 trace_next_list(struct trace_array_cpu *data, struct list_head *next)
708 * Roundrobin - but skip the head (which is not a real page):
711 if (unlikely(next == &data->trace_pages))
713 BUG_ON(next == &data->trace_pages);
719 trace_next_page(struct trace_array_cpu *data, void *addr)
721 struct list_head *next;
724 page = virt_to_page(addr);
726 next = trace_next_list(data, &page->lru);
727 page = list_entry(next, struct page, lru);
729 return page_address(page);
732 static inline struct trace_entry *
733 tracing_get_trace_entry(struct trace_array *tr, struct trace_array_cpu *data)
735 unsigned long idx, idx_next;
736 struct trace_entry *entry;
739 idx = data->trace_head_idx;
742 BUG_ON(idx * TRACE_ENTRY_SIZE >= PAGE_SIZE);
744 entry = data->trace_head + idx * TRACE_ENTRY_SIZE;
746 if (unlikely(idx_next >= ENTRIES_PER_PAGE)) {
747 data->trace_head = trace_next_page(data, data->trace_head);
751 if (data->trace_head == data->trace_tail &&
752 idx_next == data->trace_tail_idx) {
755 data->trace_tail_idx++;
756 if (data->trace_tail_idx >= ENTRIES_PER_PAGE) {
758 trace_next_page(data, data->trace_tail);
759 data->trace_tail_idx = 0;
763 data->trace_head_idx = idx_next;
769 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags)
771 struct task_struct *tsk = current;
774 pc = preempt_count();
776 entry->preempt_count = pc & 0xff;
777 entry->pid = (tsk) ? tsk->pid : 0;
778 entry->t = ftrace_now(raw_smp_processor_id());
779 entry->flags = (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
780 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
781 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
782 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
786 trace_function(struct trace_array *tr, struct trace_array_cpu *data,
787 unsigned long ip, unsigned long parent_ip, unsigned long flags)
789 struct trace_entry *entry;
790 unsigned long irq_flags;
792 raw_local_irq_save(irq_flags);
793 __raw_spin_lock(&data->lock);
794 entry = tracing_get_trace_entry(tr, data);
795 tracing_generic_entry_update(entry, flags);
796 entry->type = TRACE_FN;
798 entry->fn.parent_ip = parent_ip;
799 __raw_spin_unlock(&data->lock);
800 raw_local_irq_restore(irq_flags);
804 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
805 unsigned long ip, unsigned long parent_ip, unsigned long flags)
807 if (likely(!atomic_read(&data->disabled)))
808 trace_function(tr, data, ip, parent_ip, flags);
812 __trace_special(void *__tr, void *__data,
813 unsigned long arg1, unsigned long arg2, unsigned long arg3)
815 struct trace_array_cpu *data = __data;
816 struct trace_array *tr = __tr;
817 struct trace_entry *entry;
818 unsigned long irq_flags;
820 raw_local_irq_save(irq_flags);
821 __raw_spin_lock(&data->lock);
822 entry = tracing_get_trace_entry(tr, data);
823 tracing_generic_entry_update(entry, 0);
824 entry->type = TRACE_SPECIAL;
825 entry->special.arg1 = arg1;
826 entry->special.arg2 = arg2;
827 entry->special.arg3 = arg3;
828 __raw_spin_unlock(&data->lock);
829 raw_local_irq_restore(irq_flags);
834 void __trace_stack(struct trace_array *tr,
835 struct trace_array_cpu *data,
839 struct trace_entry *entry;
840 struct stack_trace trace;
842 if (!(trace_flags & TRACE_ITER_STACKTRACE))
845 entry = tracing_get_trace_entry(tr, data);
846 tracing_generic_entry_update(entry, flags);
847 entry->type = TRACE_STACK;
849 memset(&entry->stack, 0, sizeof(entry->stack));
851 trace.nr_entries = 0;
852 trace.max_entries = FTRACE_STACK_ENTRIES;
854 trace.entries = entry->stack.caller;
856 save_stack_trace(&trace);
860 tracing_sched_switch_trace(struct trace_array *tr,
861 struct trace_array_cpu *data,
862 struct task_struct *prev,
863 struct task_struct *next,
866 struct trace_entry *entry;
867 unsigned long irq_flags;
869 raw_local_irq_save(irq_flags);
870 __raw_spin_lock(&data->lock);
871 entry = tracing_get_trace_entry(tr, data);
872 tracing_generic_entry_update(entry, flags);
873 entry->type = TRACE_CTX;
874 entry->ctx.prev_pid = prev->pid;
875 entry->ctx.prev_prio = prev->prio;
876 entry->ctx.prev_state = prev->state;
877 entry->ctx.next_pid = next->pid;
878 entry->ctx.next_prio = next->prio;
879 entry->ctx.next_state = next->state;
880 __trace_stack(tr, data, flags, 4);
881 __raw_spin_unlock(&data->lock);
882 raw_local_irq_restore(irq_flags);
886 tracing_sched_wakeup_trace(struct trace_array *tr,
887 struct trace_array_cpu *data,
888 struct task_struct *wakee,
889 struct task_struct *curr,
892 struct trace_entry *entry;
893 unsigned long irq_flags;
895 raw_local_irq_save(irq_flags);
896 __raw_spin_lock(&data->lock);
897 entry = tracing_get_trace_entry(tr, data);
898 tracing_generic_entry_update(entry, flags);
899 entry->type = TRACE_WAKE;
900 entry->ctx.prev_pid = curr->pid;
901 entry->ctx.prev_prio = curr->prio;
902 entry->ctx.prev_state = curr->state;
903 entry->ctx.next_pid = wakee->pid;
904 entry->ctx.next_prio = wakee->prio;
905 entry->ctx.next_state = wakee->state;
906 __trace_stack(tr, data, flags, 5);
907 __raw_spin_unlock(&data->lock);
908 raw_local_irq_restore(irq_flags);
915 function_trace_call(unsigned long ip, unsigned long parent_ip)
917 struct trace_array *tr = &global_trace;
918 struct trace_array_cpu *data;
923 if (unlikely(!tracer_enabled))
926 local_irq_save(flags);
927 cpu = raw_smp_processor_id();
928 data = tr->data[cpu];
929 disabled = atomic_inc_return(&data->disabled);
931 if (likely(disabled == 1))
932 trace_function(tr, data, ip, parent_ip, flags);
934 atomic_dec(&data->disabled);
935 local_irq_restore(flags);
938 static struct ftrace_ops trace_ops __read_mostly =
940 .func = function_trace_call,
943 void tracing_start_function_trace(void)
945 register_ftrace_function(&trace_ops);
948 void tracing_stop_function_trace(void)
950 unregister_ftrace_function(&trace_ops);
954 enum trace_file_type {
955 TRACE_FILE_LAT_FMT = 1,
958 static struct trace_entry *
959 trace_entry_idx(struct trace_array *tr, struct trace_array_cpu *data,
960 struct trace_iterator *iter, int cpu)
963 struct trace_entry *array;
965 if (iter->next_idx[cpu] >= tr->entries ||
966 iter->next_idx[cpu] >= data->trace_idx ||
967 (data->trace_head == data->trace_tail &&
968 data->trace_head_idx == data->trace_tail_idx))
971 if (!iter->next_page[cpu]) {
972 /* Initialize the iterator for this cpu trace buffer */
973 WARN_ON(!data->trace_tail);
974 page = virt_to_page(data->trace_tail);
975 iter->next_page[cpu] = &page->lru;
976 iter->next_page_idx[cpu] = data->trace_tail_idx;
979 page = list_entry(iter->next_page[cpu], struct page, lru);
980 BUG_ON(&data->trace_pages == &page->lru);
982 array = page_address(page);
984 WARN_ON(iter->next_page_idx[cpu] >= ENTRIES_PER_PAGE);
985 return &array[iter->next_page_idx[cpu]];
988 static struct trace_entry *
989 find_next_entry(struct trace_iterator *iter, int *ent_cpu)
991 struct trace_array *tr = iter->tr;
992 struct trace_entry *ent, *next = NULL;
996 for_each_tracing_cpu(cpu) {
997 if (!head_page(tr->data[cpu]))
999 ent = trace_entry_idx(tr, tr->data[cpu], iter, cpu);
1001 * Pick the entry with the smallest timestamp:
1003 if (ent && (!next || ent->t < next->t)) {
1010 *ent_cpu = next_cpu;
1015 static void trace_iterator_increment(struct trace_iterator *iter)
1018 iter->next_idx[iter->cpu]++;
1019 iter->next_page_idx[iter->cpu]++;
1021 if (iter->next_page_idx[iter->cpu] >= ENTRIES_PER_PAGE) {
1022 struct trace_array_cpu *data = iter->tr->data[iter->cpu];
1024 iter->next_page_idx[iter->cpu] = 0;
1025 iter->next_page[iter->cpu] =
1026 trace_next_list(data, iter->next_page[iter->cpu]);
1030 static void trace_consume(struct trace_iterator *iter)
1032 struct trace_array_cpu *data = iter->tr->data[iter->cpu];
1034 data->trace_tail_idx++;
1035 if (data->trace_tail_idx >= ENTRIES_PER_PAGE) {
1036 data->trace_tail = trace_next_page(data, data->trace_tail);
1037 data->trace_tail_idx = 0;
1040 /* Check if we empty it, then reset the index */
1041 if (data->trace_head == data->trace_tail &&
1042 data->trace_head_idx == data->trace_tail_idx)
1043 data->trace_idx = 0;
1046 static void *find_next_entry_inc(struct trace_iterator *iter)
1048 struct trace_entry *next;
1051 next = find_next_entry(iter, &next_cpu);
1053 iter->prev_ent = iter->ent;
1054 iter->prev_cpu = iter->cpu;
1057 iter->cpu = next_cpu;
1060 trace_iterator_increment(iter);
1062 return next ? iter : NULL;
1065 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
1067 struct trace_iterator *iter = m->private;
1068 void *last_ent = iter->ent;
1074 /* can't go backwards */
1079 ent = find_next_entry_inc(iter);
1083 while (ent && iter->idx < i)
1084 ent = find_next_entry_inc(iter);
1088 if (last_ent && !ent)
1089 seq_puts(m, "\n\nvim:ft=help\n");
1094 static void *s_start(struct seq_file *m, loff_t *pos)
1096 struct trace_iterator *iter = m->private;
1101 mutex_lock(&trace_types_lock);
1103 if (!current_trace || current_trace != iter->trace) {
1104 mutex_unlock(&trace_types_lock);
1108 atomic_inc(&trace_record_cmdline_disabled);
1110 /* let the tracer grab locks here if needed */
1111 if (current_trace->start)
1112 current_trace->start(iter);
1114 if (*pos != iter->pos) {
1118 iter->prev_ent = NULL;
1119 iter->prev_cpu = -1;
1121 for_each_tracing_cpu(i) {
1122 iter->next_idx[i] = 0;
1123 iter->next_page[i] = NULL;
1126 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
1131 p = s_next(m, p, &l);
1137 static void s_stop(struct seq_file *m, void *p)
1139 struct trace_iterator *iter = m->private;
1141 atomic_dec(&trace_record_cmdline_disabled);
1143 /* let the tracer release locks here if needed */
1144 if (current_trace && current_trace == iter->trace && iter->trace->stop)
1145 iter->trace->stop(iter);
1147 mutex_unlock(&trace_types_lock);
1151 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
1153 #ifdef CONFIG_KALLSYMS
1154 char str[KSYM_SYMBOL_LEN];
1156 kallsyms_lookup(address, NULL, NULL, NULL, str);
1158 return trace_seq_printf(s, fmt, str);
1164 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
1165 unsigned long address)
1167 #ifdef CONFIG_KALLSYMS
1168 char str[KSYM_SYMBOL_LEN];
1170 sprint_symbol(str, address);
1171 return trace_seq_printf(s, fmt, str);
1176 #ifndef CONFIG_64BIT
1177 # define IP_FMT "%08lx"
1179 # define IP_FMT "%016lx"
1183 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
1188 return trace_seq_printf(s, "0");
1190 if (sym_flags & TRACE_ITER_SYM_OFFSET)
1191 ret = seq_print_sym_offset(s, "%s", ip);
1193 ret = seq_print_sym_short(s, "%s", ip);
1198 if (sym_flags & TRACE_ITER_SYM_ADDR)
1199 ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
1203 static void print_lat_help_header(struct seq_file *m)
1205 seq_puts(m, "# _------=> CPU# \n");
1206 seq_puts(m, "# / _-----=> irqs-off \n");
1207 seq_puts(m, "# | / _----=> need-resched \n");
1208 seq_puts(m, "# || / _---=> hardirq/softirq \n");
1209 seq_puts(m, "# ||| / _--=> preempt-depth \n");
1210 seq_puts(m, "# |||| / \n");
1211 seq_puts(m, "# ||||| delay \n");
1212 seq_puts(m, "# cmd pid ||||| time | caller \n");
1213 seq_puts(m, "# \\ / ||||| \\ | / \n");
1216 static void print_func_help_header(struct seq_file *m)
1218 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1219 seq_puts(m, "# | | | | |\n");
1224 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
1226 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1227 struct trace_array *tr = iter->tr;
1228 struct trace_array_cpu *data = tr->data[tr->cpu];
1229 struct tracer *type = current_trace;
1230 unsigned long total = 0;
1231 unsigned long entries = 0;
1233 const char *name = "preemption";
1238 for_each_tracing_cpu(cpu) {
1239 if (head_page(tr->data[cpu])) {
1240 total += tr->data[cpu]->trace_idx;
1241 if (tr->data[cpu]->trace_idx > tr->entries)
1242 entries += tr->entries;
1244 entries += tr->data[cpu]->trace_idx;
1248 seq_printf(m, "%s latency trace v1.1.5 on %s\n",
1250 seq_puts(m, "-----------------------------------"
1251 "---------------------------------\n");
1252 seq_printf(m, " latency: %lu us, #%lu/%lu, CPU#%d |"
1253 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1254 nsecs_to_usecs(data->saved_latency),
1258 #if defined(CONFIG_PREEMPT_NONE)
1260 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1262 #elif defined(CONFIG_PREEMPT_DESKTOP)
1267 /* These are reserved for later use */
1270 seq_printf(m, " #P:%d)\n", num_online_cpus());
1274 seq_puts(m, " -----------------\n");
1275 seq_printf(m, " | task: %.16s-%d "
1276 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1277 data->comm, data->pid, data->uid, data->nice,
1278 data->policy, data->rt_priority);
1279 seq_puts(m, " -----------------\n");
1281 if (data->critical_start) {
1282 seq_puts(m, " => started at: ");
1283 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
1284 trace_print_seq(m, &iter->seq);
1285 seq_puts(m, "\n => ended at: ");
1286 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
1287 trace_print_seq(m, &iter->seq);
1295 lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
1297 int hardirq, softirq;
1300 comm = trace_find_cmdline(entry->pid);
1302 trace_seq_printf(s, "%8.8s-%-5d ", comm, entry->pid);
1303 trace_seq_printf(s, "%d", cpu);
1304 trace_seq_printf(s, "%c%c",
1305 (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' : '.',
1306 ((entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.'));
1308 hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
1309 softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
1310 if (hardirq && softirq) {
1311 trace_seq_putc(s, 'H');
1314 trace_seq_putc(s, 'h');
1317 trace_seq_putc(s, 's');
1319 trace_seq_putc(s, '.');
1323 if (entry->preempt_count)
1324 trace_seq_printf(s, "%x", entry->preempt_count);
1326 trace_seq_puts(s, ".");
1329 unsigned long preempt_mark_thresh = 100;
1332 lat_print_timestamp(struct trace_seq *s, unsigned long long abs_usecs,
1333 unsigned long rel_usecs)
1335 trace_seq_printf(s, " %4lldus", abs_usecs);
1336 if (rel_usecs > preempt_mark_thresh)
1337 trace_seq_puts(s, "!: ");
1338 else if (rel_usecs > 1)
1339 trace_seq_puts(s, "+: ");
1341 trace_seq_puts(s, " : ");
1344 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
1347 print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
1349 struct trace_seq *s = &iter->seq;
1350 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1351 struct trace_entry *next_entry = find_next_entry(iter, NULL);
1352 unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
1353 struct trace_entry *entry = iter->ent;
1354 unsigned long abs_usecs;
1355 unsigned long rel_usecs;
1363 rel_usecs = ns2usecs(next_entry->t - entry->t);
1364 abs_usecs = ns2usecs(entry->t - iter->tr->time_start);
1367 comm = trace_find_cmdline(entry->pid);
1368 trace_seq_printf(s, "%16s %5d %d %d %08x %08x [%08lx]"
1369 " %ld.%03ldms (+%ld.%03ldms): ",
1371 entry->pid, cpu, entry->flags,
1372 entry->preempt_count, trace_idx,
1375 abs_usecs % 1000, rel_usecs/1000,
1378 lat_print_generic(s, entry, cpu);
1379 lat_print_timestamp(s, abs_usecs, rel_usecs);
1381 switch (entry->type) {
1383 seq_print_ip_sym(s, entry->fn.ip, sym_flags);
1384 trace_seq_puts(s, " (");
1385 seq_print_ip_sym(s, entry->fn.parent_ip, sym_flags);
1386 trace_seq_puts(s, ")\n");
1390 T = entry->ctx.next_state < sizeof(state_to_char) ?
1391 state_to_char[entry->ctx.next_state] : 'X';
1393 state = entry->ctx.prev_state ? __ffs(entry->ctx.prev_state) + 1 : 0;
1394 S = state < sizeof(state_to_char) - 1 ? state_to_char[state] : 'X';
1395 comm = trace_find_cmdline(entry->ctx.next_pid);
1396 trace_seq_printf(s, " %5d:%3d:%c %s %5d:%3d:%c %s\n",
1397 entry->ctx.prev_pid,
1398 entry->ctx.prev_prio,
1399 S, entry->type == TRACE_CTX ? "==>" : " +",
1400 entry->ctx.next_pid,
1401 entry->ctx.next_prio,
1405 trace_seq_printf(s, "# %ld %ld %ld\n",
1406 entry->special.arg1,
1407 entry->special.arg2,
1408 entry->special.arg3);
1411 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1413 trace_seq_puts(s, " <= ");
1414 seq_print_ip_sym(s, entry->stack.caller[i], sym_flags);
1416 trace_seq_puts(s, "\n");
1419 trace_seq_printf(s, "Unknown type %d\n", entry->type);
1424 static int print_trace_fmt(struct trace_iterator *iter)
1426 struct trace_seq *s = &iter->seq;
1427 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1428 struct trace_entry *entry;
1429 unsigned long usec_rem;
1430 unsigned long long t;
1439 comm = trace_find_cmdline(iter->ent->pid);
1441 t = ns2usecs(entry->t);
1442 usec_rem = do_div(t, 1000000ULL);
1443 secs = (unsigned long)t;
1445 ret = trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid);
1448 ret = trace_seq_printf(s, "[%02d] ", iter->cpu);
1451 ret = trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem);
1455 switch (entry->type) {
1457 ret = seq_print_ip_sym(s, entry->fn.ip, sym_flags);
1460 if ((sym_flags & TRACE_ITER_PRINT_PARENT) &&
1461 entry->fn.parent_ip) {
1462 ret = trace_seq_printf(s, " <-");
1465 ret = seq_print_ip_sym(s, entry->fn.parent_ip,
1470 ret = trace_seq_printf(s, "\n");
1476 S = entry->ctx.prev_state < sizeof(state_to_char) ?
1477 state_to_char[entry->ctx.prev_state] : 'X';
1478 T = entry->ctx.next_state < sizeof(state_to_char) ?
1479 state_to_char[entry->ctx.next_state] : 'X';
1480 ret = trace_seq_printf(s, " %5d:%3d:%c %s %5d:%3d:%c\n",
1481 entry->ctx.prev_pid,
1482 entry->ctx.prev_prio,
1484 entry->type == TRACE_CTX ? "==>" : " +",
1485 entry->ctx.next_pid,
1486 entry->ctx.next_prio,
1492 ret = trace_seq_printf(s, "# %ld %ld %ld\n",
1493 entry->special.arg1,
1494 entry->special.arg2,
1495 entry->special.arg3);
1500 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1502 ret = trace_seq_puts(s, " <= ");
1506 ret = seq_print_ip_sym(s, entry->stack.caller[i],
1511 ret = trace_seq_puts(s, "\n");
1519 static int print_raw_fmt(struct trace_iterator *iter)
1521 struct trace_seq *s = &iter->seq;
1522 struct trace_entry *entry;
1528 ret = trace_seq_printf(s, "%d %d %llu ",
1529 entry->pid, iter->cpu, entry->t);
1533 switch (entry->type) {
1535 ret = trace_seq_printf(s, "%x %x\n",
1536 entry->fn.ip, entry->fn.parent_ip);
1542 S = entry->ctx.prev_state < sizeof(state_to_char) ?
1543 state_to_char[entry->ctx.prev_state] : 'X';
1544 T = entry->ctx.next_state < sizeof(state_to_char) ?
1545 state_to_char[entry->ctx.next_state] : 'X';
1546 if (entry->type == TRACE_WAKE)
1548 ret = trace_seq_printf(s, "%d %d %c %d %d %c\n",
1549 entry->ctx.prev_pid,
1550 entry->ctx.prev_prio,
1552 entry->ctx.next_pid,
1553 entry->ctx.next_prio,
1560 ret = trace_seq_printf(s, "# %ld %ld %ld\n",
1561 entry->special.arg1,
1562 entry->special.arg2,
1563 entry->special.arg3);
1571 #define SEQ_PUT_FIELD_RET(s, x) \
1573 if (!trace_seq_putmem(s, &(x), sizeof(x))) \
1577 #define SEQ_PUT_HEX_FIELD_RET(s, x) \
1579 if (!trace_seq_putmem_hex(s, &(x), sizeof(x))) \
1583 static int print_hex_fmt(struct trace_iterator *iter)
1585 struct trace_seq *s = &iter->seq;
1586 unsigned char newline = '\n';
1587 struct trace_entry *entry;
1592 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
1593 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
1594 SEQ_PUT_HEX_FIELD_RET(s, entry->t);
1596 switch (entry->type) {
1598 SEQ_PUT_HEX_FIELD_RET(s, entry->fn.ip);
1599 SEQ_PUT_HEX_FIELD_RET(s, entry->fn.parent_ip);
1603 S = entry->ctx.prev_state < sizeof(state_to_char) ?
1604 state_to_char[entry->ctx.prev_state] : 'X';
1605 T = entry->ctx.next_state < sizeof(state_to_char) ?
1606 state_to_char[entry->ctx.next_state] : 'X';
1607 if (entry->type == TRACE_WAKE)
1609 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.prev_pid);
1610 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.prev_prio);
1611 SEQ_PUT_HEX_FIELD_RET(s, S);
1612 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.next_pid);
1613 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.next_prio);
1614 SEQ_PUT_HEX_FIELD_RET(s, entry->fn.parent_ip);
1615 SEQ_PUT_HEX_FIELD_RET(s, T);
1619 SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg1);
1620 SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg2);
1621 SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg3);
1624 SEQ_PUT_FIELD_RET(s, newline);
1629 static int print_bin_fmt(struct trace_iterator *iter)
1631 struct trace_seq *s = &iter->seq;
1632 struct trace_entry *entry;
1636 SEQ_PUT_FIELD_RET(s, entry->pid);
1637 SEQ_PUT_FIELD_RET(s, entry->cpu);
1638 SEQ_PUT_FIELD_RET(s, entry->t);
1640 switch (entry->type) {
1642 SEQ_PUT_FIELD_RET(s, entry->fn.ip);
1643 SEQ_PUT_FIELD_RET(s, entry->fn.parent_ip);
1646 SEQ_PUT_FIELD_RET(s, entry->ctx.prev_pid);
1647 SEQ_PUT_FIELD_RET(s, entry->ctx.prev_prio);
1648 SEQ_PUT_FIELD_RET(s, entry->ctx.prev_state);
1649 SEQ_PUT_FIELD_RET(s, entry->ctx.next_pid);
1650 SEQ_PUT_FIELD_RET(s, entry->ctx.next_prio);
1651 SEQ_PUT_FIELD_RET(s, entry->ctx.next_state);
1655 SEQ_PUT_FIELD_RET(s, entry->special.arg1);
1656 SEQ_PUT_FIELD_RET(s, entry->special.arg2);
1657 SEQ_PUT_FIELD_RET(s, entry->special.arg3);
1663 static int trace_empty(struct trace_iterator *iter)
1665 struct trace_array_cpu *data;
1668 for_each_tracing_cpu(cpu) {
1669 data = iter->tr->data[cpu];
1671 if (head_page(data) && data->trace_idx &&
1672 (data->trace_tail != data->trace_head ||
1673 data->trace_tail_idx != data->trace_head_idx))
1679 static int print_trace_line(struct trace_iterator *iter)
1681 if (iter->trace && iter->trace->print_line)
1682 return iter->trace->print_line(iter);
1684 if (trace_flags & TRACE_ITER_BIN)
1685 return print_bin_fmt(iter);
1687 if (trace_flags & TRACE_ITER_HEX)
1688 return print_hex_fmt(iter);
1690 if (trace_flags & TRACE_ITER_RAW)
1691 return print_raw_fmt(iter);
1693 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
1694 return print_lat_fmt(iter, iter->idx, iter->cpu);
1696 return print_trace_fmt(iter);
1699 static int s_show(struct seq_file *m, void *v)
1701 struct trace_iterator *iter = v;
1703 if (iter->ent == NULL) {
1705 seq_printf(m, "# tracer: %s\n", iter->trace->name);
1708 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1709 /* print nothing if the buffers are empty */
1710 if (trace_empty(iter))
1712 print_trace_header(m, iter);
1713 if (!(trace_flags & TRACE_ITER_VERBOSE))
1714 print_lat_help_header(m);
1716 if (!(trace_flags & TRACE_ITER_VERBOSE))
1717 print_func_help_header(m);
1720 print_trace_line(iter);
1721 trace_print_seq(m, &iter->seq);
1727 static struct seq_operations tracer_seq_ops = {
1734 static struct trace_iterator *
1735 __tracing_open(struct inode *inode, struct file *file, int *ret)
1737 struct trace_iterator *iter;
1739 if (tracing_disabled) {
1744 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1750 mutex_lock(&trace_types_lock);
1751 if (current_trace && current_trace->print_max)
1754 iter->tr = inode->i_private;
1755 iter->trace = current_trace;
1758 /* TODO stop tracer */
1759 *ret = seq_open(file, &tracer_seq_ops);
1761 struct seq_file *m = file->private_data;
1764 /* stop the trace while dumping */
1768 if (iter->trace && iter->trace->open)
1769 iter->trace->open(iter);
1774 mutex_unlock(&trace_types_lock);
1780 int tracing_open_generic(struct inode *inode, struct file *filp)
1782 if (tracing_disabled)
1785 filp->private_data = inode->i_private;
1789 int tracing_release(struct inode *inode, struct file *file)
1791 struct seq_file *m = (struct seq_file *)file->private_data;
1792 struct trace_iterator *iter = m->private;
1794 mutex_lock(&trace_types_lock);
1795 if (iter->trace && iter->trace->close)
1796 iter->trace->close(iter);
1798 /* reenable tracing if it was previously enabled */
1801 mutex_unlock(&trace_types_lock);
1803 seq_release(inode, file);
1808 static int tracing_open(struct inode *inode, struct file *file)
1812 __tracing_open(inode, file, &ret);
1817 static int tracing_lt_open(struct inode *inode, struct file *file)
1819 struct trace_iterator *iter;
1822 iter = __tracing_open(inode, file, &ret);
1825 iter->iter_flags |= TRACE_FILE_LAT_FMT;
1832 t_next(struct seq_file *m, void *v, loff_t *pos)
1834 struct tracer *t = m->private;
1846 static void *t_start(struct seq_file *m, loff_t *pos)
1848 struct tracer *t = m->private;
1851 mutex_lock(&trace_types_lock);
1852 for (; t && l < *pos; t = t_next(m, t, &l))
1858 static void t_stop(struct seq_file *m, void *p)
1860 mutex_unlock(&trace_types_lock);
1863 static int t_show(struct seq_file *m, void *v)
1865 struct tracer *t = v;
1870 seq_printf(m, "%s", t->name);
1879 static struct seq_operations show_traces_seq_ops = {
1886 static int show_traces_open(struct inode *inode, struct file *file)
1890 if (tracing_disabled)
1893 ret = seq_open(file, &show_traces_seq_ops);
1895 struct seq_file *m = file->private_data;
1896 m->private = trace_types;
1902 static struct file_operations tracing_fops = {
1903 .open = tracing_open,
1905 .llseek = seq_lseek,
1906 .release = tracing_release,
1909 static struct file_operations tracing_lt_fops = {
1910 .open = tracing_lt_open,
1912 .llseek = seq_lseek,
1913 .release = tracing_release,
1916 static struct file_operations show_traces_fops = {
1917 .open = show_traces_open,
1919 .release = seq_release,
1923 * Only trace on a CPU if the bitmask is set:
1925 static cpumask_t tracing_cpumask = CPU_MASK_ALL;
1928 * When tracing/tracing_cpu_mask is modified then this holds
1929 * the new bitmask we are about to install:
1931 static cpumask_t tracing_cpumask_new;
1934 * The tracer itself will not take this lock, but still we want
1935 * to provide a consistent cpumask to user-space:
1937 static DEFINE_MUTEX(tracing_cpumask_update_lock);
1940 * Temporary storage for the character representation of the
1941 * CPU bitmask (and one more byte for the newline):
1943 static char mask_str[NR_CPUS + 1];
1946 tracing_cpumask_read(struct file *filp, char __user *ubuf,
1947 size_t count, loff_t *ppos)
1951 mutex_lock(&tracing_cpumask_update_lock);
1953 len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
1954 if (count - len < 2) {
1958 len += sprintf(mask_str + len, "\n");
1959 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
1962 mutex_unlock(&tracing_cpumask_update_lock);
1968 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
1969 size_t count, loff_t *ppos)
1973 mutex_lock(&tracing_cpumask_update_lock);
1974 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
1978 raw_local_irq_disable();
1979 __raw_spin_lock(&ftrace_max_lock);
1980 for_each_tracing_cpu(cpu) {
1982 * Increase/decrease the disabled counter if we are
1983 * about to flip a bit in the cpumask:
1985 if (cpu_isset(cpu, tracing_cpumask) &&
1986 !cpu_isset(cpu, tracing_cpumask_new)) {
1987 atomic_inc(&global_trace.data[cpu]->disabled);
1989 if (!cpu_isset(cpu, tracing_cpumask) &&
1990 cpu_isset(cpu, tracing_cpumask_new)) {
1991 atomic_dec(&global_trace.data[cpu]->disabled);
1994 __raw_spin_unlock(&ftrace_max_lock);
1995 raw_local_irq_enable();
1997 tracing_cpumask = tracing_cpumask_new;
1999 mutex_unlock(&tracing_cpumask_update_lock);
2004 mutex_unlock(&tracing_cpumask_update_lock);
2009 static struct file_operations tracing_cpumask_fops = {
2010 .open = tracing_open_generic,
2011 .read = tracing_cpumask_read,
2012 .write = tracing_cpumask_write,
2016 tracing_iter_ctrl_read(struct file *filp, char __user *ubuf,
2017 size_t cnt, loff_t *ppos)
2024 /* calulate max size */
2025 for (i = 0; trace_options[i]; i++) {
2026 len += strlen(trace_options[i]);
2027 len += 3; /* "no" and space */
2030 /* +2 for \n and \0 */
2031 buf = kmalloc(len + 2, GFP_KERNEL);
2035 for (i = 0; trace_options[i]; i++) {
2036 if (trace_flags & (1 << i))
2037 r += sprintf(buf + r, "%s ", trace_options[i]);
2039 r += sprintf(buf + r, "no%s ", trace_options[i]);
2042 r += sprintf(buf + r, "\n");
2043 WARN_ON(r >= len + 2);
2045 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2053 tracing_iter_ctrl_write(struct file *filp, const char __user *ubuf,
2054 size_t cnt, loff_t *ppos)
2061 if (cnt >= sizeof(buf))
2064 if (copy_from_user(&buf, ubuf, cnt))
2069 if (strncmp(buf, "no", 2) == 0) {
2074 for (i = 0; trace_options[i]; i++) {
2075 int len = strlen(trace_options[i]);
2077 if (strncmp(cmp, trace_options[i], len) == 0) {
2079 trace_flags &= ~(1 << i);
2081 trace_flags |= (1 << i);
2086 * If no option could be set, return an error:
2088 if (!trace_options[i])
2096 static struct file_operations tracing_iter_fops = {
2097 .open = tracing_open_generic,
2098 .read = tracing_iter_ctrl_read,
2099 .write = tracing_iter_ctrl_write,
2102 static const char readme_msg[] =
2103 "tracing mini-HOWTO:\n\n"
2105 "# mount -t debugfs nodev /debug\n\n"
2106 "# cat /debug/tracing/available_tracers\n"
2107 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
2108 "# cat /debug/tracing/current_tracer\n"
2110 "# echo sched_switch > /debug/tracing/current_tracer\n"
2111 "# cat /debug/tracing/current_tracer\n"
2113 "# cat /debug/tracing/iter_ctrl\n"
2114 "noprint-parent nosym-offset nosym-addr noverbose\n"
2115 "# echo print-parent > /debug/tracing/iter_ctrl\n"
2116 "# echo 1 > /debug/tracing/tracing_enabled\n"
2117 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
2118 "echo 0 > /debug/tracing/tracing_enabled\n"
2122 tracing_readme_read(struct file *filp, char __user *ubuf,
2123 size_t cnt, loff_t *ppos)
2125 return simple_read_from_buffer(ubuf, cnt, ppos,
2126 readme_msg, strlen(readme_msg));
2129 static struct file_operations tracing_readme_fops = {
2130 .open = tracing_open_generic,
2131 .read = tracing_readme_read,
2135 tracing_ctrl_read(struct file *filp, char __user *ubuf,
2136 size_t cnt, loff_t *ppos)
2138 struct trace_array *tr = filp->private_data;
2142 r = sprintf(buf, "%ld\n", tr->ctrl);
2143 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2147 tracing_ctrl_write(struct file *filp, const char __user *ubuf,
2148 size_t cnt, loff_t *ppos)
2150 struct trace_array *tr = filp->private_data;
2155 if (cnt >= sizeof(buf))
2158 if (copy_from_user(&buf, ubuf, cnt))
2163 ret = strict_strtoul(buf, 10, &val);
2169 mutex_lock(&trace_types_lock);
2170 if (tr->ctrl ^ val) {
2178 if (current_trace && current_trace->ctrl_update)
2179 current_trace->ctrl_update(tr);
2181 mutex_unlock(&trace_types_lock);
2189 tracing_set_trace_read(struct file *filp, char __user *ubuf,
2190 size_t cnt, loff_t *ppos)
2192 char buf[max_tracer_type_len+2];
2195 mutex_lock(&trace_types_lock);
2197 r = sprintf(buf, "%s\n", current_trace->name);
2199 r = sprintf(buf, "\n");
2200 mutex_unlock(&trace_types_lock);
2202 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2206 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
2207 size_t cnt, loff_t *ppos)
2209 struct trace_array *tr = &global_trace;
2211 char buf[max_tracer_type_len+1];
2214 if (cnt > max_tracer_type_len)
2215 cnt = max_tracer_type_len;
2217 if (copy_from_user(&buf, ubuf, cnt))
2222 /* strip ending whitespace. */
2223 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
2226 mutex_lock(&trace_types_lock);
2227 for (t = trace_types; t; t = t->next) {
2228 if (strcmp(t->name, buf) == 0)
2231 if (!t || t == current_trace)
2234 if (current_trace && current_trace->reset)
2235 current_trace->reset(tr);
2242 mutex_unlock(&trace_types_lock);
2250 tracing_max_lat_read(struct file *filp, char __user *ubuf,
2251 size_t cnt, loff_t *ppos)
2253 unsigned long *ptr = filp->private_data;
2257 r = snprintf(buf, sizeof(buf), "%ld\n",
2258 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
2259 if (r > sizeof(buf))
2261 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2265 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
2266 size_t cnt, loff_t *ppos)
2268 long *ptr = filp->private_data;
2273 if (cnt >= sizeof(buf))
2276 if (copy_from_user(&buf, ubuf, cnt))
2281 ret = strict_strtoul(buf, 10, &val);
2290 static atomic_t tracing_reader;
2292 static int tracing_open_pipe(struct inode *inode, struct file *filp)
2294 struct trace_iterator *iter;
2296 if (tracing_disabled)
2299 /* We only allow for reader of the pipe */
2300 if (atomic_inc_return(&tracing_reader) != 1) {
2301 atomic_dec(&tracing_reader);
2305 /* create a buffer to store the information to pass to userspace */
2306 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2310 iter->tr = &global_trace;
2311 iter->trace = current_trace;
2313 filp->private_data = iter;
2318 static int tracing_release_pipe(struct inode *inode, struct file *file)
2320 struct trace_iterator *iter = file->private_data;
2323 atomic_dec(&tracing_reader);
2329 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
2331 struct trace_iterator *iter = filp->private_data;
2333 if (trace_flags & TRACE_ITER_BLOCK) {
2335 * Always select as readable when in blocking mode
2337 return POLLIN | POLLRDNORM;
2339 if (!trace_empty(iter))
2340 return POLLIN | POLLRDNORM;
2341 poll_wait(filp, &trace_wait, poll_table);
2342 if (!trace_empty(iter))
2343 return POLLIN | POLLRDNORM;
2353 tracing_read_pipe(struct file *filp, char __user *ubuf,
2354 size_t cnt, loff_t *ppos)
2356 struct trace_iterator *iter = filp->private_data;
2357 struct trace_array_cpu *data;
2358 static cpumask_t mask;
2360 unsigned long flags;
2361 #ifdef CONFIG_FTRACE
2369 /* return any leftover data */
2370 if (iter->seq.len > start) {
2371 len = iter->seq.len - start;
2374 ret = copy_to_user(ubuf, iter->seq.buffer + start, cnt);
2383 trace_seq_reset(&iter->seq);
2386 while (trace_empty(iter)) {
2388 if ((filp->f_flags & O_NONBLOCK))
2392 * This is a make-shift waitqueue. The reason we don't use
2393 * an actual wait queue is because:
2394 * 1) we only ever have one waiter
2395 * 2) the tracing, traces all functions, we don't want
2396 * the overhead of calling wake_up and friends
2397 * (and tracing them too)
2398 * Anyway, this is really very primitive wakeup.
2400 set_current_state(TASK_INTERRUPTIBLE);
2401 iter->tr->waiter = current;
2403 /* sleep for one second, and try again. */
2404 schedule_timeout(HZ);
2406 iter->tr->waiter = NULL;
2408 if (signal_pending(current))
2411 if (iter->trace != current_trace)
2415 * We block until we read something and tracing is disabled.
2416 * We still block if tracing is disabled, but we have never
2417 * read anything. This allows a user to cat this file, and
2418 * then enable tracing. But after we have read something,
2419 * we give an EOF when tracing is again disabled.
2421 * iter->pos will be 0 if we haven't read anything.
2423 if (!tracer_enabled && iter->pos)
2429 /* stop when tracing is finished */
2430 if (trace_empty(iter))
2433 if (cnt >= PAGE_SIZE)
2434 cnt = PAGE_SIZE - 1;
2436 /* reset all but tr, trace, and overruns */
2438 memset(&iter->seq, 0,
2439 sizeof(struct trace_iterator) -
2440 offsetof(struct trace_iterator, seq));
2443 * We need to stop all tracing on all CPUS to read the
2444 * the next buffer. This is a bit expensive, but is
2445 * not done often. We fill all what we can read,
2446 * and then release the locks again.
2450 local_irq_save(flags);
2451 #ifdef CONFIG_FTRACE
2452 ftrace_save = ftrace_enabled;
2456 for_each_tracing_cpu(cpu) {
2457 data = iter->tr->data[cpu];
2459 if (!head_page(data) || !data->trace_idx)
2462 atomic_inc(&data->disabled);
2466 for_each_cpu_mask(cpu, mask) {
2467 data = iter->tr->data[cpu];
2468 __raw_spin_lock(&data->lock);
2470 if (data->overrun > iter->last_overrun[cpu])
2471 iter->overrun[cpu] +=
2472 data->overrun - iter->last_overrun[cpu];
2473 iter->last_overrun[cpu] = data->overrun;
2476 while (find_next_entry_inc(iter) != NULL) {
2477 int len = iter->seq.len;
2479 ret = print_trace_line(iter);
2481 /* don't print partial lines */
2482 iter->seq.len = len;
2486 trace_consume(iter);
2488 if (iter->seq.len >= cnt)
2492 for_each_cpu_mask(cpu, mask) {
2493 data = iter->tr->data[cpu];
2494 __raw_spin_unlock(&data->lock);
2497 for_each_cpu_mask(cpu, mask) {
2498 data = iter->tr->data[cpu];
2499 atomic_dec(&data->disabled);
2501 #ifdef CONFIG_FTRACE
2502 ftrace_enabled = ftrace_save;
2504 local_irq_restore(flags);
2506 /* Now copy what we have to the user */
2507 read = iter->seq.len;
2511 ret = copy_to_user(ubuf, iter->seq.buffer, read);
2513 if (read < iter->seq.len)
2516 trace_seq_reset(&iter->seq);
2525 tracing_entries_read(struct file *filp, char __user *ubuf,
2526 size_t cnt, loff_t *ppos)
2528 struct trace_array *tr = filp->private_data;
2532 r = sprintf(buf, "%lu\n", tr->entries);
2533 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2537 tracing_entries_write(struct file *filp, const char __user *ubuf,
2538 size_t cnt, loff_t *ppos)
2544 if (cnt >= sizeof(buf))
2547 if (copy_from_user(&buf, ubuf, cnt))
2552 ret = strict_strtoul(buf, 10, &val);
2556 /* must have at least 1 entry */
2560 mutex_lock(&trace_types_lock);
2562 if (current_trace != &no_tracer) {
2564 pr_info("ftrace: set current_tracer to none"
2565 " before modifying buffer size\n");
2569 if (val > global_trace.entries) {
2570 while (global_trace.entries < val) {
2571 if (trace_alloc_page()) {
2577 /* include the number of entries in val (inc of page entries) */
2578 while (global_trace.entries > val + (ENTRIES_PER_PAGE - 1))
2585 max_tr.entries = global_trace.entries;
2586 mutex_unlock(&trace_types_lock);
2591 static struct file_operations tracing_max_lat_fops = {
2592 .open = tracing_open_generic,
2593 .read = tracing_max_lat_read,
2594 .write = tracing_max_lat_write,
2597 static struct file_operations tracing_ctrl_fops = {
2598 .open = tracing_open_generic,
2599 .read = tracing_ctrl_read,
2600 .write = tracing_ctrl_write,
2603 static struct file_operations set_tracer_fops = {
2604 .open = tracing_open_generic,
2605 .read = tracing_set_trace_read,
2606 .write = tracing_set_trace_write,
2609 static struct file_operations tracing_pipe_fops = {
2610 .open = tracing_open_pipe,
2611 .poll = tracing_poll_pipe,
2612 .read = tracing_read_pipe,
2613 .release = tracing_release_pipe,
2616 static struct file_operations tracing_entries_fops = {
2617 .open = tracing_open_generic,
2618 .read = tracing_entries_read,
2619 .write = tracing_entries_write,
2622 #ifdef CONFIG_DYNAMIC_FTRACE
2625 tracing_read_long(struct file *filp, char __user *ubuf,
2626 size_t cnt, loff_t *ppos)
2628 unsigned long *p = filp->private_data;
2632 r = sprintf(buf, "%ld\n", *p);
2634 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2637 static struct file_operations tracing_read_long_fops = {
2638 .open = tracing_open_generic,
2639 .read = tracing_read_long,
2643 static struct dentry *d_tracer;
2645 struct dentry *tracing_init_dentry(void)
2652 d_tracer = debugfs_create_dir("tracing", NULL);
2654 if (!d_tracer && !once) {
2656 pr_warning("Could not create debugfs directory 'tracing'\n");
2663 #ifdef CONFIG_FTRACE_SELFTEST
2664 /* Let selftest have access to static functions in this file */
2665 #include "trace_selftest.c"
2668 static __init void tracer_init_debugfs(void)
2670 struct dentry *d_tracer;
2671 struct dentry *entry;
2673 d_tracer = tracing_init_dentry();
2675 entry = debugfs_create_file("tracing_enabled", 0644, d_tracer,
2676 &global_trace, &tracing_ctrl_fops);
2678 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
2680 entry = debugfs_create_file("iter_ctrl", 0644, d_tracer,
2681 NULL, &tracing_iter_fops);
2683 pr_warning("Could not create debugfs 'iter_ctrl' entry\n");
2685 entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer,
2686 NULL, &tracing_cpumask_fops);
2688 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
2690 entry = debugfs_create_file("latency_trace", 0444, d_tracer,
2691 &global_trace, &tracing_lt_fops);
2693 pr_warning("Could not create debugfs 'latency_trace' entry\n");
2695 entry = debugfs_create_file("trace", 0444, d_tracer,
2696 &global_trace, &tracing_fops);
2698 pr_warning("Could not create debugfs 'trace' entry\n");
2700 entry = debugfs_create_file("available_tracers", 0444, d_tracer,
2701 &global_trace, &show_traces_fops);
2703 pr_warning("Could not create debugfs 'trace' entry\n");
2705 entry = debugfs_create_file("current_tracer", 0444, d_tracer,
2706 &global_trace, &set_tracer_fops);
2708 pr_warning("Could not create debugfs 'trace' entry\n");
2710 entry = debugfs_create_file("tracing_max_latency", 0644, d_tracer,
2711 &tracing_max_latency,
2712 &tracing_max_lat_fops);
2714 pr_warning("Could not create debugfs "
2715 "'tracing_max_latency' entry\n");
2717 entry = debugfs_create_file("tracing_thresh", 0644, d_tracer,
2718 &tracing_thresh, &tracing_max_lat_fops);
2720 pr_warning("Could not create debugfs "
2721 "'tracing_threash' entry\n");
2722 entry = debugfs_create_file("README", 0644, d_tracer,
2723 NULL, &tracing_readme_fops);
2725 pr_warning("Could not create debugfs 'README' entry\n");
2727 entry = debugfs_create_file("trace_pipe", 0644, d_tracer,
2728 NULL, &tracing_pipe_fops);
2730 pr_warning("Could not create debugfs "
2731 "'tracing_threash' entry\n");
2733 entry = debugfs_create_file("trace_entries", 0644, d_tracer,
2734 &global_trace, &tracing_entries_fops);
2736 pr_warning("Could not create debugfs "
2737 "'tracing_threash' entry\n");
2739 #ifdef CONFIG_DYNAMIC_FTRACE
2740 entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
2741 &ftrace_update_tot_cnt,
2742 &tracing_read_long_fops);
2744 pr_warning("Could not create debugfs "
2745 "'dyn_ftrace_total_info' entry\n");
2749 static int trace_alloc_page(void)
2751 struct trace_array_cpu *data;
2752 struct page *page, *tmp;
2757 /* first allocate a page for each CPU */
2758 for_each_tracing_cpu(i) {
2759 array = (void *)__get_free_page(GFP_KERNEL);
2760 if (array == NULL) {
2761 printk(KERN_ERR "tracer: failed to allocate page"
2762 "for trace buffer!\n");
2766 page = virt_to_page(array);
2767 list_add(&page->lru, &pages);
2769 /* Only allocate if we are actually using the max trace */
2770 #ifdef CONFIG_TRACER_MAX_TRACE
2771 array = (void *)__get_free_page(GFP_KERNEL);
2772 if (array == NULL) {
2773 printk(KERN_ERR "tracer: failed to allocate page"
2774 "for trace buffer!\n");
2777 page = virt_to_page(array);
2778 list_add(&page->lru, &pages);
2782 /* Now that we successfully allocate a page per CPU, add them */
2783 for_each_tracing_cpu(i) {
2784 data = global_trace.data[i];
2785 page = list_entry(pages.next, struct page, lru);
2786 list_del_init(&page->lru);
2787 list_add_tail(&page->lru, &data->trace_pages);
2790 #ifdef CONFIG_TRACER_MAX_TRACE
2791 data = max_tr.data[i];
2792 page = list_entry(pages.next, struct page, lru);
2793 list_del_init(&page->lru);
2794 list_add_tail(&page->lru, &data->trace_pages);
2798 global_trace.entries += ENTRIES_PER_PAGE;
2803 list_for_each_entry_safe(page, tmp, &pages, lru) {
2804 list_del_init(&page->lru);
2810 static int trace_free_page(void)
2812 struct trace_array_cpu *data;
2814 struct list_head *p;
2818 /* free one page from each buffer */
2819 for_each_tracing_cpu(i) {
2820 data = global_trace.data[i];
2821 p = data->trace_pages.next;
2822 if (p == &data->trace_pages) {
2823 /* should never happen */
2825 tracing_disabled = 1;
2829 page = list_entry(p, struct page, lru);
2831 list_del(&page->lru);
2834 tracing_reset(data);
2836 #ifdef CONFIG_TRACER_MAX_TRACE
2837 data = max_tr.data[i];
2838 p = data->trace_pages.next;
2839 if (p == &data->trace_pages) {
2840 /* should never happen */
2842 tracing_disabled = 1;
2846 page = list_entry(p, struct page, lru);
2848 list_del(&page->lru);
2851 tracing_reset(data);
2854 global_trace.entries -= ENTRIES_PER_PAGE;
2859 __init static int tracer_alloc_buffers(void)
2861 struct trace_array_cpu *data;
2868 global_trace.ctrl = tracer_enabled;
2870 /* TODO: make the number of buffers hot pluggable with CPUS */
2871 tracing_nr_buffers = num_possible_cpus();
2872 tracing_buffer_mask = cpu_possible_map;
2874 /* Allocate the first page for all buffers */
2875 for_each_tracing_cpu(i) {
2876 data = global_trace.data[i] = &per_cpu(global_trace_cpu, i);
2877 max_tr.data[i] = &per_cpu(max_data, i);
2879 array = (void *)__get_free_page(GFP_KERNEL);
2880 if (array == NULL) {
2881 printk(KERN_ERR "tracer: failed to allocate page"
2882 "for trace buffer!\n");
2886 /* set the array to the list */
2887 INIT_LIST_HEAD(&data->trace_pages);
2888 page = virt_to_page(array);
2889 list_add(&page->lru, &data->trace_pages);
2890 /* use the LRU flag to differentiate the two buffers */
2893 data->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
2894 max_tr.data[i]->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
2896 /* Only allocate if we are actually using the max trace */
2897 #ifdef CONFIG_TRACER_MAX_TRACE
2898 array = (void *)__get_free_page(GFP_KERNEL);
2899 if (array == NULL) {
2900 printk(KERN_ERR "tracer: failed to allocate page"
2901 "for trace buffer!\n");
2905 INIT_LIST_HEAD(&max_tr.data[i]->trace_pages);
2906 page = virt_to_page(array);
2907 list_add(&page->lru, &max_tr.data[i]->trace_pages);
2913 * Since we allocate by orders of pages, we may be able to
2916 global_trace.entries = ENTRIES_PER_PAGE;
2919 while (global_trace.entries < trace_nr_entries) {
2920 if (trace_alloc_page())
2924 max_tr.entries = global_trace.entries;
2926 pr_info("tracer: %d pages allocated for %ld",
2927 pages, trace_nr_entries);
2928 pr_info(" entries of %ld bytes\n", (long)TRACE_ENTRY_SIZE);
2929 pr_info(" actual entries %ld\n", global_trace.entries);
2931 tracer_init_debugfs();
2933 trace_init_cmdlines();
2935 register_tracer(&no_tracer);
2936 current_trace = &no_tracer;
2938 /* All seems OK, enable tracing */
2939 tracing_disabled = 0;
2944 for (i-- ; i >= 0; i--) {
2945 struct page *page, *tmp;
2946 struct trace_array_cpu *data = global_trace.data[i];
2949 list_for_each_entry_safe(page, tmp,
2950 &data->trace_pages, lru) {
2951 list_del_init(&page->lru);
2956 #ifdef CONFIG_TRACER_MAX_TRACE
2957 data = max_tr.data[i];
2959 list_for_each_entry_safe(page, tmp,
2960 &data->trace_pages, lru) {
2961 list_del_init(&page->lru);
2969 fs_initcall(tracer_alloc_buffers);