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 ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
411 if (s->len <= s->readpos)
414 len = s->len - s->readpos;
417 ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
426 trace_print_seq(struct seq_file *m, struct trace_seq *s)
428 int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
431 seq_puts(m, s->buffer);
437 * flip the trace buffers between two trace descriptors.
438 * This usually is the buffers between the global_trace and
439 * the max_tr to record a snapshot of a current trace.
441 * The ftrace_max_lock must be held.
444 flip_trace(struct trace_array_cpu *tr1, struct trace_array_cpu *tr2)
446 struct list_head flip_pages;
448 INIT_LIST_HEAD(&flip_pages);
450 memcpy(&tr1->trace_head_idx, &tr2->trace_head_idx,
451 sizeof(struct trace_array_cpu) -
452 offsetof(struct trace_array_cpu, trace_head_idx));
456 list_splice_init(&tr1->trace_pages, &flip_pages);
457 list_splice_init(&tr2->trace_pages, &tr1->trace_pages);
458 list_splice_init(&flip_pages, &tr2->trace_pages);
459 BUG_ON(!list_empty(&flip_pages));
465 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
467 * @tsk: the task with the latency
468 * @cpu: The cpu that initiated the trace.
470 * Flip the buffers between the @tr and the max_tr and record information
471 * about which task was the cause of this latency.
474 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
476 struct trace_array_cpu *data;
479 WARN_ON_ONCE(!irqs_disabled());
480 __raw_spin_lock(&ftrace_max_lock);
481 /* clear out all the previous traces */
482 for_each_tracing_cpu(i) {
484 flip_trace(max_tr.data[i], data);
488 __update_max_tr(tr, tsk, cpu);
489 __raw_spin_unlock(&ftrace_max_lock);
493 * update_max_tr_single - only copy one trace over, and reset the rest
495 * @tsk - task with the latency
496 * @cpu - the cpu of the buffer to copy.
498 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
501 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
503 struct trace_array_cpu *data = tr->data[cpu];
506 WARN_ON_ONCE(!irqs_disabled());
507 __raw_spin_lock(&ftrace_max_lock);
508 for_each_tracing_cpu(i)
509 tracing_reset(max_tr.data[i]);
511 flip_trace(max_tr.data[cpu], data);
514 __update_max_tr(tr, tsk, cpu);
515 __raw_spin_unlock(&ftrace_max_lock);
519 * register_tracer - register a tracer with the ftrace system.
520 * @type - the plugin for the tracer
522 * Register a new plugin tracer.
524 int register_tracer(struct tracer *type)
531 pr_info("Tracer must have a name\n");
535 mutex_lock(&trace_types_lock);
536 for (t = trace_types; t; t = t->next) {
537 if (strcmp(type->name, t->name) == 0) {
539 pr_info("Trace %s already registered\n",
546 #ifdef CONFIG_FTRACE_STARTUP_TEST
547 if (type->selftest) {
548 struct tracer *saved_tracer = current_trace;
549 struct trace_array_cpu *data;
550 struct trace_array *tr = &global_trace;
551 int saved_ctrl = tr->ctrl;
554 * Run a selftest on this tracer.
555 * Here we reset the trace buffer, and set the current
556 * tracer to be this tracer. The tracer can then run some
557 * internal tracing to verify that everything is in order.
558 * If we fail, we do not register this tracer.
560 for_each_tracing_cpu(i) {
562 if (!head_page(data))
566 current_trace = type;
568 /* the test is responsible for initializing and enabling */
569 pr_info("Testing tracer %s: ", type->name);
570 ret = type->selftest(type, tr);
571 /* the test is responsible for resetting too */
572 current_trace = saved_tracer;
573 tr->ctrl = saved_ctrl;
575 printk(KERN_CONT "FAILED!\n");
578 /* Only reset on passing, to avoid touching corrupted buffers */
579 for_each_tracing_cpu(i) {
581 if (!head_page(data))
585 printk(KERN_CONT "PASSED\n");
589 type->next = trace_types;
591 len = strlen(type->name);
592 if (len > max_tracer_type_len)
593 max_tracer_type_len = len;
596 mutex_unlock(&trace_types_lock);
601 void unregister_tracer(struct tracer *type)
606 mutex_lock(&trace_types_lock);
607 for (t = &trace_types; *t; t = &(*t)->next) {
611 pr_info("Trace %s not registered\n", type->name);
616 if (strlen(type->name) != max_tracer_type_len)
619 max_tracer_type_len = 0;
620 for (t = &trace_types; *t; t = &(*t)->next) {
621 len = strlen((*t)->name);
622 if (len > max_tracer_type_len)
623 max_tracer_type_len = len;
626 mutex_unlock(&trace_types_lock);
629 void tracing_reset(struct trace_array_cpu *data)
633 data->trace_head = data->trace_tail = head_page(data);
634 data->trace_head_idx = 0;
635 data->trace_tail_idx = 0;
638 #define SAVED_CMDLINES 128
639 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
640 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
641 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
642 static int cmdline_idx;
643 static DEFINE_SPINLOCK(trace_cmdline_lock);
645 /* trace in all context switches */
646 atomic_t trace_record_cmdline_enabled __read_mostly;
648 /* temporary disable recording */
649 atomic_t trace_record_cmdline_disabled __read_mostly;
651 static void trace_init_cmdlines(void)
653 memset(&map_pid_to_cmdline, -1, sizeof(map_pid_to_cmdline));
654 memset(&map_cmdline_to_pid, -1, sizeof(map_cmdline_to_pid));
658 void trace_stop_cmdline_recording(void);
660 static void trace_save_cmdline(struct task_struct *tsk)
665 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
669 * It's not the end of the world if we don't get
670 * the lock, but we also don't want to spin
671 * nor do we want to disable interrupts,
672 * so if we miss here, then better luck next time.
674 if (!spin_trylock(&trace_cmdline_lock))
677 idx = map_pid_to_cmdline[tsk->pid];
678 if (idx >= SAVED_CMDLINES) {
679 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
681 map = map_cmdline_to_pid[idx];
682 if (map <= PID_MAX_DEFAULT)
683 map_pid_to_cmdline[map] = (unsigned)-1;
685 map_pid_to_cmdline[tsk->pid] = idx;
690 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
692 spin_unlock(&trace_cmdline_lock);
695 static char *trace_find_cmdline(int pid)
697 char *cmdline = "<...>";
703 if (pid > PID_MAX_DEFAULT)
706 map = map_pid_to_cmdline[pid];
707 if (map >= SAVED_CMDLINES)
710 cmdline = saved_cmdlines[map];
716 void tracing_record_cmdline(struct task_struct *tsk)
718 if (atomic_read(&trace_record_cmdline_disabled))
721 trace_save_cmdline(tsk);
724 static inline struct list_head *
725 trace_next_list(struct trace_array_cpu *data, struct list_head *next)
728 * Roundrobin - but skip the head (which is not a real page):
731 if (unlikely(next == &data->trace_pages))
733 BUG_ON(next == &data->trace_pages);
739 trace_next_page(struct trace_array_cpu *data, void *addr)
741 struct list_head *next;
744 page = virt_to_page(addr);
746 next = trace_next_list(data, &page->lru);
747 page = list_entry(next, struct page, lru);
749 return page_address(page);
752 static inline struct trace_entry *
753 tracing_get_trace_entry(struct trace_array *tr, struct trace_array_cpu *data)
755 unsigned long idx, idx_next;
756 struct trace_entry *entry;
759 idx = data->trace_head_idx;
762 BUG_ON(idx * TRACE_ENTRY_SIZE >= PAGE_SIZE);
764 entry = data->trace_head + idx * TRACE_ENTRY_SIZE;
766 if (unlikely(idx_next >= ENTRIES_PER_PAGE)) {
767 data->trace_head = trace_next_page(data, data->trace_head);
771 if (data->trace_head == data->trace_tail &&
772 idx_next == data->trace_tail_idx) {
775 data->trace_tail_idx++;
776 if (data->trace_tail_idx >= ENTRIES_PER_PAGE) {
778 trace_next_page(data, data->trace_tail);
779 data->trace_tail_idx = 0;
783 data->trace_head_idx = idx_next;
789 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags)
791 struct task_struct *tsk = current;
794 pc = preempt_count();
796 entry->preempt_count = pc & 0xff;
797 entry->pid = (tsk) ? tsk->pid : 0;
798 entry->t = ftrace_now(raw_smp_processor_id());
799 entry->flags = (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
800 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
801 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
802 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
806 trace_function(struct trace_array *tr, struct trace_array_cpu *data,
807 unsigned long ip, unsigned long parent_ip, unsigned long flags)
809 struct trace_entry *entry;
810 unsigned long irq_flags;
812 raw_local_irq_save(irq_flags);
813 __raw_spin_lock(&data->lock);
814 entry = tracing_get_trace_entry(tr, data);
815 tracing_generic_entry_update(entry, flags);
816 entry->type = TRACE_FN;
818 entry->fn.parent_ip = parent_ip;
819 __raw_spin_unlock(&data->lock);
820 raw_local_irq_restore(irq_flags);
824 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
825 unsigned long ip, unsigned long parent_ip, unsigned long flags)
827 if (likely(!atomic_read(&data->disabled)))
828 trace_function(tr, data, ip, parent_ip, flags);
831 void __trace_stack(struct trace_array *tr,
832 struct trace_array_cpu *data,
836 struct trace_entry *entry;
837 struct stack_trace trace;
839 if (!(trace_flags & TRACE_ITER_STACKTRACE))
842 entry = tracing_get_trace_entry(tr, data);
843 tracing_generic_entry_update(entry, flags);
844 entry->type = TRACE_STACK;
846 memset(&entry->stack, 0, sizeof(entry->stack));
848 trace.nr_entries = 0;
849 trace.max_entries = FTRACE_STACK_ENTRIES;
851 trace.entries = entry->stack.caller;
853 save_stack_trace(&trace);
857 __trace_special(void *__tr, void *__data,
858 unsigned long arg1, unsigned long arg2, unsigned long arg3)
860 struct trace_array_cpu *data = __data;
861 struct trace_array *tr = __tr;
862 struct trace_entry *entry;
863 unsigned long irq_flags;
865 raw_local_irq_save(irq_flags);
866 __raw_spin_lock(&data->lock);
867 entry = tracing_get_trace_entry(tr, data);
868 tracing_generic_entry_update(entry, 0);
869 entry->type = TRACE_SPECIAL;
870 entry->special.arg1 = arg1;
871 entry->special.arg2 = arg2;
872 entry->special.arg3 = arg3;
873 __trace_stack(tr, data, irq_flags, 4);
874 __raw_spin_unlock(&data->lock);
875 raw_local_irq_restore(irq_flags);
881 tracing_sched_switch_trace(struct trace_array *tr,
882 struct trace_array_cpu *data,
883 struct task_struct *prev,
884 struct task_struct *next,
887 struct trace_entry *entry;
888 unsigned long irq_flags;
890 raw_local_irq_save(irq_flags);
891 __raw_spin_lock(&data->lock);
892 entry = tracing_get_trace_entry(tr, data);
893 tracing_generic_entry_update(entry, flags);
894 entry->type = TRACE_CTX;
895 entry->ctx.prev_pid = prev->pid;
896 entry->ctx.prev_prio = prev->prio;
897 entry->ctx.prev_state = prev->state;
898 entry->ctx.next_pid = next->pid;
899 entry->ctx.next_prio = next->prio;
900 entry->ctx.next_state = next->state;
901 __trace_stack(tr, data, flags, 4);
902 __raw_spin_unlock(&data->lock);
903 raw_local_irq_restore(irq_flags);
907 tracing_sched_wakeup_trace(struct trace_array *tr,
908 struct trace_array_cpu *data,
909 struct task_struct *wakee,
910 struct task_struct *curr,
913 struct trace_entry *entry;
914 unsigned long irq_flags;
916 raw_local_irq_save(irq_flags);
917 __raw_spin_lock(&data->lock);
918 entry = tracing_get_trace_entry(tr, data);
919 tracing_generic_entry_update(entry, flags);
920 entry->type = TRACE_WAKE;
921 entry->ctx.prev_pid = curr->pid;
922 entry->ctx.prev_prio = curr->prio;
923 entry->ctx.prev_state = curr->state;
924 entry->ctx.next_pid = wakee->pid;
925 entry->ctx.next_prio = wakee->prio;
926 entry->ctx.next_state = wakee->state;
927 __trace_stack(tr, data, flags, 5);
928 __raw_spin_unlock(&data->lock);
929 raw_local_irq_restore(irq_flags);
936 function_trace_call(unsigned long ip, unsigned long parent_ip)
938 struct trace_array *tr = &global_trace;
939 struct trace_array_cpu *data;
944 if (unlikely(!tracer_enabled))
947 local_irq_save(flags);
948 cpu = raw_smp_processor_id();
949 data = tr->data[cpu];
950 disabled = atomic_inc_return(&data->disabled);
952 if (likely(disabled == 1))
953 trace_function(tr, data, ip, parent_ip, flags);
955 atomic_dec(&data->disabled);
956 local_irq_restore(flags);
959 static struct ftrace_ops trace_ops __read_mostly =
961 .func = function_trace_call,
964 void tracing_start_function_trace(void)
966 register_ftrace_function(&trace_ops);
969 void tracing_stop_function_trace(void)
971 unregister_ftrace_function(&trace_ops);
975 enum trace_file_type {
976 TRACE_FILE_LAT_FMT = 1,
979 static struct trace_entry *
980 trace_entry_idx(struct trace_array *tr, struct trace_array_cpu *data,
981 struct trace_iterator *iter, int cpu)
984 struct trace_entry *array;
986 if (iter->next_idx[cpu] >= tr->entries ||
987 iter->next_idx[cpu] >= data->trace_idx ||
988 (data->trace_head == data->trace_tail &&
989 data->trace_head_idx == data->trace_tail_idx))
992 if (!iter->next_page[cpu]) {
993 /* Initialize the iterator for this cpu trace buffer */
994 WARN_ON(!data->trace_tail);
995 page = virt_to_page(data->trace_tail);
996 iter->next_page[cpu] = &page->lru;
997 iter->next_page_idx[cpu] = data->trace_tail_idx;
1000 page = list_entry(iter->next_page[cpu], struct page, lru);
1001 BUG_ON(&data->trace_pages == &page->lru);
1003 array = page_address(page);
1005 WARN_ON(iter->next_page_idx[cpu] >= ENTRIES_PER_PAGE);
1006 return &array[iter->next_page_idx[cpu]];
1009 static struct trace_entry *
1010 find_next_entry(struct trace_iterator *iter, int *ent_cpu)
1012 struct trace_array *tr = iter->tr;
1013 struct trace_entry *ent, *next = NULL;
1017 for_each_tracing_cpu(cpu) {
1018 if (!head_page(tr->data[cpu]))
1020 ent = trace_entry_idx(tr, tr->data[cpu], iter, cpu);
1022 * Pick the entry with the smallest timestamp:
1024 if (ent && (!next || ent->t < next->t)) {
1031 *ent_cpu = next_cpu;
1036 static void trace_iterator_increment(struct trace_iterator *iter)
1039 iter->next_idx[iter->cpu]++;
1040 iter->next_page_idx[iter->cpu]++;
1042 if (iter->next_page_idx[iter->cpu] >= ENTRIES_PER_PAGE) {
1043 struct trace_array_cpu *data = iter->tr->data[iter->cpu];
1045 iter->next_page_idx[iter->cpu] = 0;
1046 iter->next_page[iter->cpu] =
1047 trace_next_list(data, iter->next_page[iter->cpu]);
1051 static void trace_consume(struct trace_iterator *iter)
1053 struct trace_array_cpu *data = iter->tr->data[iter->cpu];
1055 data->trace_tail_idx++;
1056 if (data->trace_tail_idx >= ENTRIES_PER_PAGE) {
1057 data->trace_tail = trace_next_page(data, data->trace_tail);
1058 data->trace_tail_idx = 0;
1061 /* Check if we empty it, then reset the index */
1062 if (data->trace_head == data->trace_tail &&
1063 data->trace_head_idx == data->trace_tail_idx)
1064 data->trace_idx = 0;
1067 static void *find_next_entry_inc(struct trace_iterator *iter)
1069 struct trace_entry *next;
1072 next = find_next_entry(iter, &next_cpu);
1074 iter->prev_ent = iter->ent;
1075 iter->prev_cpu = iter->cpu;
1078 iter->cpu = next_cpu;
1081 trace_iterator_increment(iter);
1083 return next ? iter : NULL;
1086 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
1088 struct trace_iterator *iter = m->private;
1089 void *last_ent = iter->ent;
1095 /* can't go backwards */
1100 ent = find_next_entry_inc(iter);
1104 while (ent && iter->idx < i)
1105 ent = find_next_entry_inc(iter);
1109 if (last_ent && !ent)
1110 seq_puts(m, "\n\nvim:ft=help\n");
1115 static void *s_start(struct seq_file *m, loff_t *pos)
1117 struct trace_iterator *iter = m->private;
1122 mutex_lock(&trace_types_lock);
1124 if (!current_trace || current_trace != iter->trace) {
1125 mutex_unlock(&trace_types_lock);
1129 atomic_inc(&trace_record_cmdline_disabled);
1131 /* let the tracer grab locks here if needed */
1132 if (current_trace->start)
1133 current_trace->start(iter);
1135 if (*pos != iter->pos) {
1139 iter->prev_ent = NULL;
1140 iter->prev_cpu = -1;
1142 for_each_tracing_cpu(i) {
1143 iter->next_idx[i] = 0;
1144 iter->next_page[i] = NULL;
1147 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
1152 p = s_next(m, p, &l);
1158 static void s_stop(struct seq_file *m, void *p)
1160 struct trace_iterator *iter = m->private;
1162 atomic_dec(&trace_record_cmdline_disabled);
1164 /* let the tracer release locks here if needed */
1165 if (current_trace && current_trace == iter->trace && iter->trace->stop)
1166 iter->trace->stop(iter);
1168 mutex_unlock(&trace_types_lock);
1172 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
1174 #ifdef CONFIG_KALLSYMS
1175 char str[KSYM_SYMBOL_LEN];
1177 kallsyms_lookup(address, NULL, NULL, NULL, str);
1179 return trace_seq_printf(s, fmt, str);
1185 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
1186 unsigned long address)
1188 #ifdef CONFIG_KALLSYMS
1189 char str[KSYM_SYMBOL_LEN];
1191 sprint_symbol(str, address);
1192 return trace_seq_printf(s, fmt, str);
1197 #ifndef CONFIG_64BIT
1198 # define IP_FMT "%08lx"
1200 # define IP_FMT "%016lx"
1204 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
1209 return trace_seq_printf(s, "0");
1211 if (sym_flags & TRACE_ITER_SYM_OFFSET)
1212 ret = seq_print_sym_offset(s, "%s", ip);
1214 ret = seq_print_sym_short(s, "%s", ip);
1219 if (sym_flags & TRACE_ITER_SYM_ADDR)
1220 ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
1224 static void print_lat_help_header(struct seq_file *m)
1226 seq_puts(m, "# _------=> CPU# \n");
1227 seq_puts(m, "# / _-----=> irqs-off \n");
1228 seq_puts(m, "# | / _----=> need-resched \n");
1229 seq_puts(m, "# || / _---=> hardirq/softirq \n");
1230 seq_puts(m, "# ||| / _--=> preempt-depth \n");
1231 seq_puts(m, "# |||| / \n");
1232 seq_puts(m, "# ||||| delay \n");
1233 seq_puts(m, "# cmd pid ||||| time | caller \n");
1234 seq_puts(m, "# \\ / ||||| \\ | / \n");
1237 static void print_func_help_header(struct seq_file *m)
1239 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1240 seq_puts(m, "# | | | | |\n");
1245 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
1247 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1248 struct trace_array *tr = iter->tr;
1249 struct trace_array_cpu *data = tr->data[tr->cpu];
1250 struct tracer *type = current_trace;
1251 unsigned long total = 0;
1252 unsigned long entries = 0;
1254 const char *name = "preemption";
1259 for_each_tracing_cpu(cpu) {
1260 if (head_page(tr->data[cpu])) {
1261 total += tr->data[cpu]->trace_idx;
1262 if (tr->data[cpu]->trace_idx > tr->entries)
1263 entries += tr->entries;
1265 entries += tr->data[cpu]->trace_idx;
1269 seq_printf(m, "%s latency trace v1.1.5 on %s\n",
1271 seq_puts(m, "-----------------------------------"
1272 "---------------------------------\n");
1273 seq_printf(m, " latency: %lu us, #%lu/%lu, CPU#%d |"
1274 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1275 nsecs_to_usecs(data->saved_latency),
1279 #if defined(CONFIG_PREEMPT_NONE)
1281 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1283 #elif defined(CONFIG_PREEMPT_DESKTOP)
1288 /* These are reserved for later use */
1291 seq_printf(m, " #P:%d)\n", num_online_cpus());
1295 seq_puts(m, " -----------------\n");
1296 seq_printf(m, " | task: %.16s-%d "
1297 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1298 data->comm, data->pid, data->uid, data->nice,
1299 data->policy, data->rt_priority);
1300 seq_puts(m, " -----------------\n");
1302 if (data->critical_start) {
1303 seq_puts(m, " => started at: ");
1304 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
1305 trace_print_seq(m, &iter->seq);
1306 seq_puts(m, "\n => ended at: ");
1307 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
1308 trace_print_seq(m, &iter->seq);
1316 lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
1318 int hardirq, softirq;
1321 comm = trace_find_cmdline(entry->pid);
1323 trace_seq_printf(s, "%8.8s-%-5d ", comm, entry->pid);
1324 trace_seq_printf(s, "%d", cpu);
1325 trace_seq_printf(s, "%c%c",
1326 (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' : '.',
1327 ((entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.'));
1329 hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
1330 softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
1331 if (hardirq && softirq) {
1332 trace_seq_putc(s, 'H');
1335 trace_seq_putc(s, 'h');
1338 trace_seq_putc(s, 's');
1340 trace_seq_putc(s, '.');
1344 if (entry->preempt_count)
1345 trace_seq_printf(s, "%x", entry->preempt_count);
1347 trace_seq_puts(s, ".");
1350 unsigned long preempt_mark_thresh = 100;
1353 lat_print_timestamp(struct trace_seq *s, unsigned long long abs_usecs,
1354 unsigned long rel_usecs)
1356 trace_seq_printf(s, " %4lldus", abs_usecs);
1357 if (rel_usecs > preempt_mark_thresh)
1358 trace_seq_puts(s, "!: ");
1359 else if (rel_usecs > 1)
1360 trace_seq_puts(s, "+: ");
1362 trace_seq_puts(s, " : ");
1365 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
1368 print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
1370 struct trace_seq *s = &iter->seq;
1371 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1372 struct trace_entry *next_entry = find_next_entry(iter, NULL);
1373 unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
1374 struct trace_entry *entry = iter->ent;
1375 unsigned long abs_usecs;
1376 unsigned long rel_usecs;
1384 rel_usecs = ns2usecs(next_entry->t - entry->t);
1385 abs_usecs = ns2usecs(entry->t - iter->tr->time_start);
1388 comm = trace_find_cmdline(entry->pid);
1389 trace_seq_printf(s, "%16s %5d %d %d %08x %08x [%08lx]"
1390 " %ld.%03ldms (+%ld.%03ldms): ",
1392 entry->pid, cpu, entry->flags,
1393 entry->preempt_count, trace_idx,
1396 abs_usecs % 1000, rel_usecs/1000,
1399 lat_print_generic(s, entry, cpu);
1400 lat_print_timestamp(s, abs_usecs, rel_usecs);
1402 switch (entry->type) {
1404 seq_print_ip_sym(s, entry->fn.ip, sym_flags);
1405 trace_seq_puts(s, " (");
1406 seq_print_ip_sym(s, entry->fn.parent_ip, sym_flags);
1407 trace_seq_puts(s, ")\n");
1411 T = entry->ctx.next_state < sizeof(state_to_char) ?
1412 state_to_char[entry->ctx.next_state] : 'X';
1414 state = entry->ctx.prev_state ? __ffs(entry->ctx.prev_state) + 1 : 0;
1415 S = state < sizeof(state_to_char) - 1 ? state_to_char[state] : 'X';
1416 comm = trace_find_cmdline(entry->ctx.next_pid);
1417 trace_seq_printf(s, " %5d:%3d:%c %s %5d:%3d:%c %s\n",
1418 entry->ctx.prev_pid,
1419 entry->ctx.prev_prio,
1420 S, entry->type == TRACE_CTX ? "==>" : " +",
1421 entry->ctx.next_pid,
1422 entry->ctx.next_prio,
1426 trace_seq_printf(s, "# %ld %ld %ld\n",
1427 entry->special.arg1,
1428 entry->special.arg2,
1429 entry->special.arg3);
1432 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1434 trace_seq_puts(s, " <= ");
1435 seq_print_ip_sym(s, entry->stack.caller[i], sym_flags);
1437 trace_seq_puts(s, "\n");
1440 trace_seq_printf(s, "Unknown type %d\n", entry->type);
1445 static int print_trace_fmt(struct trace_iterator *iter)
1447 struct trace_seq *s = &iter->seq;
1448 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1449 struct trace_entry *entry;
1450 unsigned long usec_rem;
1451 unsigned long long t;
1460 comm = trace_find_cmdline(iter->ent->pid);
1462 t = ns2usecs(entry->t);
1463 usec_rem = do_div(t, 1000000ULL);
1464 secs = (unsigned long)t;
1466 ret = trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid);
1469 ret = trace_seq_printf(s, "[%02d] ", iter->cpu);
1472 ret = trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem);
1476 switch (entry->type) {
1478 ret = seq_print_ip_sym(s, entry->fn.ip, sym_flags);
1481 if ((sym_flags & TRACE_ITER_PRINT_PARENT) &&
1482 entry->fn.parent_ip) {
1483 ret = trace_seq_printf(s, " <-");
1486 ret = seq_print_ip_sym(s, entry->fn.parent_ip,
1491 ret = trace_seq_printf(s, "\n");
1497 S = entry->ctx.prev_state < sizeof(state_to_char) ?
1498 state_to_char[entry->ctx.prev_state] : 'X';
1499 T = entry->ctx.next_state < sizeof(state_to_char) ?
1500 state_to_char[entry->ctx.next_state] : 'X';
1501 ret = trace_seq_printf(s, " %5d:%3d:%c %s %5d:%3d:%c\n",
1502 entry->ctx.prev_pid,
1503 entry->ctx.prev_prio,
1505 entry->type == TRACE_CTX ? "==>" : " +",
1506 entry->ctx.next_pid,
1507 entry->ctx.next_prio,
1513 ret = trace_seq_printf(s, "# %ld %ld %ld\n",
1514 entry->special.arg1,
1515 entry->special.arg2,
1516 entry->special.arg3);
1521 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1523 ret = trace_seq_puts(s, " <= ");
1527 ret = seq_print_ip_sym(s, entry->stack.caller[i],
1532 ret = trace_seq_puts(s, "\n");
1540 static int print_raw_fmt(struct trace_iterator *iter)
1542 struct trace_seq *s = &iter->seq;
1543 struct trace_entry *entry;
1549 ret = trace_seq_printf(s, "%d %d %llu ",
1550 entry->pid, iter->cpu, entry->t);
1554 switch (entry->type) {
1556 ret = trace_seq_printf(s, "%x %x\n",
1557 entry->fn.ip, entry->fn.parent_ip);
1563 S = entry->ctx.prev_state < sizeof(state_to_char) ?
1564 state_to_char[entry->ctx.prev_state] : 'X';
1565 T = entry->ctx.next_state < sizeof(state_to_char) ?
1566 state_to_char[entry->ctx.next_state] : 'X';
1567 if (entry->type == TRACE_WAKE)
1569 ret = trace_seq_printf(s, "%d %d %c %d %d %c\n",
1570 entry->ctx.prev_pid,
1571 entry->ctx.prev_prio,
1573 entry->ctx.next_pid,
1574 entry->ctx.next_prio,
1581 ret = trace_seq_printf(s, "# %ld %ld %ld\n",
1582 entry->special.arg1,
1583 entry->special.arg2,
1584 entry->special.arg3);
1592 #define SEQ_PUT_FIELD_RET(s, x) \
1594 if (!trace_seq_putmem(s, &(x), sizeof(x))) \
1598 #define SEQ_PUT_HEX_FIELD_RET(s, x) \
1600 if (!trace_seq_putmem_hex(s, &(x), sizeof(x))) \
1604 static int print_hex_fmt(struct trace_iterator *iter)
1606 struct trace_seq *s = &iter->seq;
1607 unsigned char newline = '\n';
1608 struct trace_entry *entry;
1613 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
1614 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
1615 SEQ_PUT_HEX_FIELD_RET(s, entry->t);
1617 switch (entry->type) {
1619 SEQ_PUT_HEX_FIELD_RET(s, entry->fn.ip);
1620 SEQ_PUT_HEX_FIELD_RET(s, entry->fn.parent_ip);
1624 S = entry->ctx.prev_state < sizeof(state_to_char) ?
1625 state_to_char[entry->ctx.prev_state] : 'X';
1626 T = entry->ctx.next_state < sizeof(state_to_char) ?
1627 state_to_char[entry->ctx.next_state] : 'X';
1628 if (entry->type == TRACE_WAKE)
1630 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.prev_pid);
1631 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.prev_prio);
1632 SEQ_PUT_HEX_FIELD_RET(s, S);
1633 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.next_pid);
1634 SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.next_prio);
1635 SEQ_PUT_HEX_FIELD_RET(s, entry->fn.parent_ip);
1636 SEQ_PUT_HEX_FIELD_RET(s, T);
1640 SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg1);
1641 SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg2);
1642 SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg3);
1645 SEQ_PUT_FIELD_RET(s, newline);
1650 static int print_bin_fmt(struct trace_iterator *iter)
1652 struct trace_seq *s = &iter->seq;
1653 struct trace_entry *entry;
1657 SEQ_PUT_FIELD_RET(s, entry->pid);
1658 SEQ_PUT_FIELD_RET(s, entry->cpu);
1659 SEQ_PUT_FIELD_RET(s, entry->t);
1661 switch (entry->type) {
1663 SEQ_PUT_FIELD_RET(s, entry->fn.ip);
1664 SEQ_PUT_FIELD_RET(s, entry->fn.parent_ip);
1667 SEQ_PUT_FIELD_RET(s, entry->ctx.prev_pid);
1668 SEQ_PUT_FIELD_RET(s, entry->ctx.prev_prio);
1669 SEQ_PUT_FIELD_RET(s, entry->ctx.prev_state);
1670 SEQ_PUT_FIELD_RET(s, entry->ctx.next_pid);
1671 SEQ_PUT_FIELD_RET(s, entry->ctx.next_prio);
1672 SEQ_PUT_FIELD_RET(s, entry->ctx.next_state);
1676 SEQ_PUT_FIELD_RET(s, entry->special.arg1);
1677 SEQ_PUT_FIELD_RET(s, entry->special.arg2);
1678 SEQ_PUT_FIELD_RET(s, entry->special.arg3);
1684 static int trace_empty(struct trace_iterator *iter)
1686 struct trace_array_cpu *data;
1689 for_each_tracing_cpu(cpu) {
1690 data = iter->tr->data[cpu];
1692 if (head_page(data) && data->trace_idx &&
1693 (data->trace_tail != data->trace_head ||
1694 data->trace_tail_idx != data->trace_head_idx))
1700 static int print_trace_line(struct trace_iterator *iter)
1702 if (iter->trace && iter->trace->print_line)
1703 return iter->trace->print_line(iter);
1705 if (trace_flags & TRACE_ITER_BIN)
1706 return print_bin_fmt(iter);
1708 if (trace_flags & TRACE_ITER_HEX)
1709 return print_hex_fmt(iter);
1711 if (trace_flags & TRACE_ITER_RAW)
1712 return print_raw_fmt(iter);
1714 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
1715 return print_lat_fmt(iter, iter->idx, iter->cpu);
1717 return print_trace_fmt(iter);
1720 static int s_show(struct seq_file *m, void *v)
1722 struct trace_iterator *iter = v;
1724 if (iter->ent == NULL) {
1726 seq_printf(m, "# tracer: %s\n", iter->trace->name);
1729 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1730 /* print nothing if the buffers are empty */
1731 if (trace_empty(iter))
1733 print_trace_header(m, iter);
1734 if (!(trace_flags & TRACE_ITER_VERBOSE))
1735 print_lat_help_header(m);
1737 if (!(trace_flags & TRACE_ITER_VERBOSE))
1738 print_func_help_header(m);
1741 print_trace_line(iter);
1742 trace_print_seq(m, &iter->seq);
1748 static struct seq_operations tracer_seq_ops = {
1755 static struct trace_iterator *
1756 __tracing_open(struct inode *inode, struct file *file, int *ret)
1758 struct trace_iterator *iter;
1760 if (tracing_disabled) {
1765 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1771 mutex_lock(&trace_types_lock);
1772 if (current_trace && current_trace->print_max)
1775 iter->tr = inode->i_private;
1776 iter->trace = current_trace;
1779 /* TODO stop tracer */
1780 *ret = seq_open(file, &tracer_seq_ops);
1782 struct seq_file *m = file->private_data;
1785 /* stop the trace while dumping */
1789 if (iter->trace && iter->trace->open)
1790 iter->trace->open(iter);
1795 mutex_unlock(&trace_types_lock);
1801 int tracing_open_generic(struct inode *inode, struct file *filp)
1803 if (tracing_disabled)
1806 filp->private_data = inode->i_private;
1810 int tracing_release(struct inode *inode, struct file *file)
1812 struct seq_file *m = (struct seq_file *)file->private_data;
1813 struct trace_iterator *iter = m->private;
1815 mutex_lock(&trace_types_lock);
1816 if (iter->trace && iter->trace->close)
1817 iter->trace->close(iter);
1819 /* reenable tracing if it was previously enabled */
1822 mutex_unlock(&trace_types_lock);
1824 seq_release(inode, file);
1829 static int tracing_open(struct inode *inode, struct file *file)
1833 __tracing_open(inode, file, &ret);
1838 static int tracing_lt_open(struct inode *inode, struct file *file)
1840 struct trace_iterator *iter;
1843 iter = __tracing_open(inode, file, &ret);
1846 iter->iter_flags |= TRACE_FILE_LAT_FMT;
1853 t_next(struct seq_file *m, void *v, loff_t *pos)
1855 struct tracer *t = m->private;
1867 static void *t_start(struct seq_file *m, loff_t *pos)
1869 struct tracer *t = m->private;
1872 mutex_lock(&trace_types_lock);
1873 for (; t && l < *pos; t = t_next(m, t, &l))
1879 static void t_stop(struct seq_file *m, void *p)
1881 mutex_unlock(&trace_types_lock);
1884 static int t_show(struct seq_file *m, void *v)
1886 struct tracer *t = v;
1891 seq_printf(m, "%s", t->name);
1900 static struct seq_operations show_traces_seq_ops = {
1907 static int show_traces_open(struct inode *inode, struct file *file)
1911 if (tracing_disabled)
1914 ret = seq_open(file, &show_traces_seq_ops);
1916 struct seq_file *m = file->private_data;
1917 m->private = trace_types;
1923 static struct file_operations tracing_fops = {
1924 .open = tracing_open,
1926 .llseek = seq_lseek,
1927 .release = tracing_release,
1930 static struct file_operations tracing_lt_fops = {
1931 .open = tracing_lt_open,
1933 .llseek = seq_lseek,
1934 .release = tracing_release,
1937 static struct file_operations show_traces_fops = {
1938 .open = show_traces_open,
1940 .release = seq_release,
1944 * Only trace on a CPU if the bitmask is set:
1946 static cpumask_t tracing_cpumask = CPU_MASK_ALL;
1949 * When tracing/tracing_cpu_mask is modified then this holds
1950 * the new bitmask we are about to install:
1952 static cpumask_t tracing_cpumask_new;
1955 * The tracer itself will not take this lock, but still we want
1956 * to provide a consistent cpumask to user-space:
1958 static DEFINE_MUTEX(tracing_cpumask_update_lock);
1961 * Temporary storage for the character representation of the
1962 * CPU bitmask (and one more byte for the newline):
1964 static char mask_str[NR_CPUS + 1];
1967 tracing_cpumask_read(struct file *filp, char __user *ubuf,
1968 size_t count, loff_t *ppos)
1972 mutex_lock(&tracing_cpumask_update_lock);
1974 len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
1975 if (count - len < 2) {
1979 len += sprintf(mask_str + len, "\n");
1980 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
1983 mutex_unlock(&tracing_cpumask_update_lock);
1989 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
1990 size_t count, loff_t *ppos)
1994 mutex_lock(&tracing_cpumask_update_lock);
1995 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
1999 raw_local_irq_disable();
2000 __raw_spin_lock(&ftrace_max_lock);
2001 for_each_tracing_cpu(cpu) {
2003 * Increase/decrease the disabled counter if we are
2004 * about to flip a bit in the cpumask:
2006 if (cpu_isset(cpu, tracing_cpumask) &&
2007 !cpu_isset(cpu, tracing_cpumask_new)) {
2008 atomic_inc(&global_trace.data[cpu]->disabled);
2010 if (!cpu_isset(cpu, tracing_cpumask) &&
2011 cpu_isset(cpu, tracing_cpumask_new)) {
2012 atomic_dec(&global_trace.data[cpu]->disabled);
2015 __raw_spin_unlock(&ftrace_max_lock);
2016 raw_local_irq_enable();
2018 tracing_cpumask = tracing_cpumask_new;
2020 mutex_unlock(&tracing_cpumask_update_lock);
2025 mutex_unlock(&tracing_cpumask_update_lock);
2030 static struct file_operations tracing_cpumask_fops = {
2031 .open = tracing_open_generic,
2032 .read = tracing_cpumask_read,
2033 .write = tracing_cpumask_write,
2037 tracing_iter_ctrl_read(struct file *filp, char __user *ubuf,
2038 size_t cnt, loff_t *ppos)
2045 /* calulate max size */
2046 for (i = 0; trace_options[i]; i++) {
2047 len += strlen(trace_options[i]);
2048 len += 3; /* "no" and space */
2051 /* +2 for \n and \0 */
2052 buf = kmalloc(len + 2, GFP_KERNEL);
2056 for (i = 0; trace_options[i]; i++) {
2057 if (trace_flags & (1 << i))
2058 r += sprintf(buf + r, "%s ", trace_options[i]);
2060 r += sprintf(buf + r, "no%s ", trace_options[i]);
2063 r += sprintf(buf + r, "\n");
2064 WARN_ON(r >= len + 2);
2066 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2074 tracing_iter_ctrl_write(struct file *filp, const char __user *ubuf,
2075 size_t cnt, loff_t *ppos)
2082 if (cnt >= sizeof(buf))
2085 if (copy_from_user(&buf, ubuf, cnt))
2090 if (strncmp(buf, "no", 2) == 0) {
2095 for (i = 0; trace_options[i]; i++) {
2096 int len = strlen(trace_options[i]);
2098 if (strncmp(cmp, trace_options[i], len) == 0) {
2100 trace_flags &= ~(1 << i);
2102 trace_flags |= (1 << i);
2107 * If no option could be set, return an error:
2109 if (!trace_options[i])
2117 static struct file_operations tracing_iter_fops = {
2118 .open = tracing_open_generic,
2119 .read = tracing_iter_ctrl_read,
2120 .write = tracing_iter_ctrl_write,
2123 static const char readme_msg[] =
2124 "tracing mini-HOWTO:\n\n"
2126 "# mount -t debugfs nodev /debug\n\n"
2127 "# cat /debug/tracing/available_tracers\n"
2128 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
2129 "# cat /debug/tracing/current_tracer\n"
2131 "# echo sched_switch > /debug/tracing/current_tracer\n"
2132 "# cat /debug/tracing/current_tracer\n"
2134 "# cat /debug/tracing/iter_ctrl\n"
2135 "noprint-parent nosym-offset nosym-addr noverbose\n"
2136 "# echo print-parent > /debug/tracing/iter_ctrl\n"
2137 "# echo 1 > /debug/tracing/tracing_enabled\n"
2138 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
2139 "echo 0 > /debug/tracing/tracing_enabled\n"
2143 tracing_readme_read(struct file *filp, char __user *ubuf,
2144 size_t cnt, loff_t *ppos)
2146 return simple_read_from_buffer(ubuf, cnt, ppos,
2147 readme_msg, strlen(readme_msg));
2150 static struct file_operations tracing_readme_fops = {
2151 .open = tracing_open_generic,
2152 .read = tracing_readme_read,
2156 tracing_ctrl_read(struct file *filp, char __user *ubuf,
2157 size_t cnt, loff_t *ppos)
2159 struct trace_array *tr = filp->private_data;
2163 r = sprintf(buf, "%ld\n", tr->ctrl);
2164 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2168 tracing_ctrl_write(struct file *filp, const char __user *ubuf,
2169 size_t cnt, loff_t *ppos)
2171 struct trace_array *tr = filp->private_data;
2176 if (cnt >= sizeof(buf))
2179 if (copy_from_user(&buf, ubuf, cnt))
2184 ret = strict_strtoul(buf, 10, &val);
2190 mutex_lock(&trace_types_lock);
2191 if (tr->ctrl ^ val) {
2199 if (current_trace && current_trace->ctrl_update)
2200 current_trace->ctrl_update(tr);
2202 mutex_unlock(&trace_types_lock);
2210 tracing_set_trace_read(struct file *filp, char __user *ubuf,
2211 size_t cnt, loff_t *ppos)
2213 char buf[max_tracer_type_len+2];
2216 mutex_lock(&trace_types_lock);
2218 r = sprintf(buf, "%s\n", current_trace->name);
2220 r = sprintf(buf, "\n");
2221 mutex_unlock(&trace_types_lock);
2223 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2227 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
2228 size_t cnt, loff_t *ppos)
2230 struct trace_array *tr = &global_trace;
2232 char buf[max_tracer_type_len+1];
2235 if (cnt > max_tracer_type_len)
2236 cnt = max_tracer_type_len;
2238 if (copy_from_user(&buf, ubuf, cnt))
2243 /* strip ending whitespace. */
2244 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
2247 mutex_lock(&trace_types_lock);
2248 for (t = trace_types; t; t = t->next) {
2249 if (strcmp(t->name, buf) == 0)
2252 if (!t || t == current_trace)
2255 if (current_trace && current_trace->reset)
2256 current_trace->reset(tr);
2263 mutex_unlock(&trace_types_lock);
2271 tracing_max_lat_read(struct file *filp, char __user *ubuf,
2272 size_t cnt, loff_t *ppos)
2274 unsigned long *ptr = filp->private_data;
2278 r = snprintf(buf, sizeof(buf), "%ld\n",
2279 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
2280 if (r > sizeof(buf))
2282 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2286 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
2287 size_t cnt, loff_t *ppos)
2289 long *ptr = filp->private_data;
2294 if (cnt >= sizeof(buf))
2297 if (copy_from_user(&buf, ubuf, cnt))
2302 ret = strict_strtoul(buf, 10, &val);
2311 static atomic_t tracing_reader;
2313 static int tracing_open_pipe(struct inode *inode, struct file *filp)
2315 struct trace_iterator *iter;
2317 if (tracing_disabled)
2320 /* We only allow for reader of the pipe */
2321 if (atomic_inc_return(&tracing_reader) != 1) {
2322 atomic_dec(&tracing_reader);
2326 /* create a buffer to store the information to pass to userspace */
2327 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2331 mutex_lock(&trace_types_lock);
2332 iter->tr = &global_trace;
2333 iter->trace = current_trace;
2334 filp->private_data = iter;
2336 if (iter->trace->pipe_open)
2337 iter->trace->pipe_open(iter);
2338 mutex_unlock(&trace_types_lock);
2343 static int tracing_release_pipe(struct inode *inode, struct file *file)
2345 struct trace_iterator *iter = file->private_data;
2348 atomic_dec(&tracing_reader);
2354 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
2356 struct trace_iterator *iter = filp->private_data;
2358 if (trace_flags & TRACE_ITER_BLOCK) {
2360 * Always select as readable when in blocking mode
2362 return POLLIN | POLLRDNORM;
2364 if (!trace_empty(iter))
2365 return POLLIN | POLLRDNORM;
2366 poll_wait(filp, &trace_wait, poll_table);
2367 if (!trace_empty(iter))
2368 return POLLIN | POLLRDNORM;
2378 tracing_read_pipe(struct file *filp, char __user *ubuf,
2379 size_t cnt, loff_t *ppos)
2381 struct trace_iterator *iter = filp->private_data;
2382 struct trace_array_cpu *data;
2383 static cpumask_t mask;
2384 unsigned long flags;
2385 #ifdef CONFIG_FTRACE
2391 /* return any leftover data */
2392 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
2397 trace_seq_reset(&iter->seq);
2399 mutex_lock(&trace_types_lock);
2400 if (iter->trace->read) {
2401 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
2406 while (trace_empty(iter)) {
2408 if ((filp->f_flags & O_NONBLOCK)) {
2414 * This is a make-shift waitqueue. The reason we don't use
2415 * an actual wait queue is because:
2416 * 1) we only ever have one waiter
2417 * 2) the tracing, traces all functions, we don't want
2418 * the overhead of calling wake_up and friends
2419 * (and tracing them too)
2420 * Anyway, this is really very primitive wakeup.
2422 set_current_state(TASK_INTERRUPTIBLE);
2423 iter->tr->waiter = current;
2425 mutex_unlock(&trace_types_lock);
2427 /* sleep for 100 msecs, and try again. */
2428 schedule_timeout(HZ/10);
2430 mutex_lock(&trace_types_lock);
2432 iter->tr->waiter = NULL;
2434 if (signal_pending(current)) {
2439 if (iter->trace != current_trace)
2443 * We block until we read something and tracing is disabled.
2444 * We still block if tracing is disabled, but we have never
2445 * read anything. This allows a user to cat this file, and
2446 * then enable tracing. But after we have read something,
2447 * we give an EOF when tracing is again disabled.
2449 * iter->pos will be 0 if we haven't read anything.
2451 if (!tracer_enabled && iter->pos)
2457 /* stop when tracing is finished */
2458 if (trace_empty(iter))
2461 if (cnt >= PAGE_SIZE)
2462 cnt = PAGE_SIZE - 1;
2464 /* reset all but tr, trace, and overruns */
2465 memset(&iter->seq, 0,
2466 sizeof(struct trace_iterator) -
2467 offsetof(struct trace_iterator, seq));
2471 * We need to stop all tracing on all CPUS to read the
2472 * the next buffer. This is a bit expensive, but is
2473 * not done often. We fill all what we can read,
2474 * and then release the locks again.
2478 local_irq_save(flags);
2479 #ifdef CONFIG_FTRACE
2480 ftrace_save = ftrace_enabled;
2484 for_each_tracing_cpu(cpu) {
2485 data = iter->tr->data[cpu];
2487 if (!head_page(data) || !data->trace_idx)
2490 atomic_inc(&data->disabled);
2494 for_each_cpu_mask(cpu, mask) {
2495 data = iter->tr->data[cpu];
2496 __raw_spin_lock(&data->lock);
2498 if (data->overrun > iter->last_overrun[cpu])
2499 iter->overrun[cpu] +=
2500 data->overrun - iter->last_overrun[cpu];
2501 iter->last_overrun[cpu] = data->overrun;
2504 while (find_next_entry_inc(iter) != NULL) {
2506 int len = iter->seq.len;
2508 ret = print_trace_line(iter);
2510 /* don't print partial lines */
2511 iter->seq.len = len;
2515 trace_consume(iter);
2517 if (iter->seq.len >= cnt)
2521 for_each_cpu_mask(cpu, mask) {
2522 data = iter->tr->data[cpu];
2523 __raw_spin_unlock(&data->lock);
2526 for_each_cpu_mask(cpu, mask) {
2527 data = iter->tr->data[cpu];
2528 atomic_dec(&data->disabled);
2530 #ifdef CONFIG_FTRACE
2531 ftrace_enabled = ftrace_save;
2533 local_irq_restore(flags);
2535 /* Now copy what we have to the user */
2536 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
2537 if (iter->seq.readpos >= iter->seq.len)
2538 trace_seq_reset(&iter->seq);
2543 mutex_unlock(&trace_types_lock);
2549 tracing_entries_read(struct file *filp, char __user *ubuf,
2550 size_t cnt, loff_t *ppos)
2552 struct trace_array *tr = filp->private_data;
2556 r = sprintf(buf, "%lu\n", tr->entries);
2557 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2561 tracing_entries_write(struct file *filp, const char __user *ubuf,
2562 size_t cnt, loff_t *ppos)
2568 if (cnt >= sizeof(buf))
2571 if (copy_from_user(&buf, ubuf, cnt))
2576 ret = strict_strtoul(buf, 10, &val);
2580 /* must have at least 1 entry */
2584 mutex_lock(&trace_types_lock);
2586 if (current_trace != &no_tracer) {
2588 pr_info("ftrace: set current_tracer to none"
2589 " before modifying buffer size\n");
2593 if (val > global_trace.entries) {
2594 while (global_trace.entries < val) {
2595 if (trace_alloc_page()) {
2601 /* include the number of entries in val (inc of page entries) */
2602 while (global_trace.entries > val + (ENTRIES_PER_PAGE - 1))
2609 max_tr.entries = global_trace.entries;
2610 mutex_unlock(&trace_types_lock);
2615 static struct file_operations tracing_max_lat_fops = {
2616 .open = tracing_open_generic,
2617 .read = tracing_max_lat_read,
2618 .write = tracing_max_lat_write,
2621 static struct file_operations tracing_ctrl_fops = {
2622 .open = tracing_open_generic,
2623 .read = tracing_ctrl_read,
2624 .write = tracing_ctrl_write,
2627 static struct file_operations set_tracer_fops = {
2628 .open = tracing_open_generic,
2629 .read = tracing_set_trace_read,
2630 .write = tracing_set_trace_write,
2633 static struct file_operations tracing_pipe_fops = {
2634 .open = tracing_open_pipe,
2635 .poll = tracing_poll_pipe,
2636 .read = tracing_read_pipe,
2637 .release = tracing_release_pipe,
2640 static struct file_operations tracing_entries_fops = {
2641 .open = tracing_open_generic,
2642 .read = tracing_entries_read,
2643 .write = tracing_entries_write,
2646 #ifdef CONFIG_DYNAMIC_FTRACE
2649 tracing_read_long(struct file *filp, char __user *ubuf,
2650 size_t cnt, loff_t *ppos)
2652 unsigned long *p = filp->private_data;
2656 r = sprintf(buf, "%ld\n", *p);
2658 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2661 static struct file_operations tracing_read_long_fops = {
2662 .open = tracing_open_generic,
2663 .read = tracing_read_long,
2667 static struct dentry *d_tracer;
2669 struct dentry *tracing_init_dentry(void)
2676 d_tracer = debugfs_create_dir("tracing", NULL);
2678 if (!d_tracer && !once) {
2680 pr_warning("Could not create debugfs directory 'tracing'\n");
2687 #ifdef CONFIG_FTRACE_SELFTEST
2688 /* Let selftest have access to static functions in this file */
2689 #include "trace_selftest.c"
2692 static __init void tracer_init_debugfs(void)
2694 struct dentry *d_tracer;
2695 struct dentry *entry;
2697 d_tracer = tracing_init_dentry();
2699 entry = debugfs_create_file("tracing_enabled", 0644, d_tracer,
2700 &global_trace, &tracing_ctrl_fops);
2702 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
2704 entry = debugfs_create_file("iter_ctrl", 0644, d_tracer,
2705 NULL, &tracing_iter_fops);
2707 pr_warning("Could not create debugfs 'iter_ctrl' entry\n");
2709 entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer,
2710 NULL, &tracing_cpumask_fops);
2712 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
2714 entry = debugfs_create_file("latency_trace", 0444, d_tracer,
2715 &global_trace, &tracing_lt_fops);
2717 pr_warning("Could not create debugfs 'latency_trace' entry\n");
2719 entry = debugfs_create_file("trace", 0444, d_tracer,
2720 &global_trace, &tracing_fops);
2722 pr_warning("Could not create debugfs 'trace' entry\n");
2724 entry = debugfs_create_file("available_tracers", 0444, d_tracer,
2725 &global_trace, &show_traces_fops);
2727 pr_warning("Could not create debugfs 'trace' entry\n");
2729 entry = debugfs_create_file("current_tracer", 0444, d_tracer,
2730 &global_trace, &set_tracer_fops);
2732 pr_warning("Could not create debugfs 'trace' entry\n");
2734 entry = debugfs_create_file("tracing_max_latency", 0644, d_tracer,
2735 &tracing_max_latency,
2736 &tracing_max_lat_fops);
2738 pr_warning("Could not create debugfs "
2739 "'tracing_max_latency' entry\n");
2741 entry = debugfs_create_file("tracing_thresh", 0644, d_tracer,
2742 &tracing_thresh, &tracing_max_lat_fops);
2744 pr_warning("Could not create debugfs "
2745 "'tracing_threash' entry\n");
2746 entry = debugfs_create_file("README", 0644, d_tracer,
2747 NULL, &tracing_readme_fops);
2749 pr_warning("Could not create debugfs 'README' entry\n");
2751 entry = debugfs_create_file("trace_pipe", 0644, d_tracer,
2752 NULL, &tracing_pipe_fops);
2754 pr_warning("Could not create debugfs "
2755 "'tracing_threash' entry\n");
2757 entry = debugfs_create_file("trace_entries", 0644, d_tracer,
2758 &global_trace, &tracing_entries_fops);
2760 pr_warning("Could not create debugfs "
2761 "'tracing_threash' entry\n");
2763 #ifdef CONFIG_DYNAMIC_FTRACE
2764 entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
2765 &ftrace_update_tot_cnt,
2766 &tracing_read_long_fops);
2768 pr_warning("Could not create debugfs "
2769 "'dyn_ftrace_total_info' entry\n");
2773 static int trace_alloc_page(void)
2775 struct trace_array_cpu *data;
2776 struct page *page, *tmp;
2781 /* first allocate a page for each CPU */
2782 for_each_tracing_cpu(i) {
2783 array = (void *)__get_free_page(GFP_KERNEL);
2784 if (array == NULL) {
2785 printk(KERN_ERR "tracer: failed to allocate page"
2786 "for trace buffer!\n");
2790 page = virt_to_page(array);
2791 list_add(&page->lru, &pages);
2793 /* Only allocate if we are actually using the max trace */
2794 #ifdef CONFIG_TRACER_MAX_TRACE
2795 array = (void *)__get_free_page(GFP_KERNEL);
2796 if (array == NULL) {
2797 printk(KERN_ERR "tracer: failed to allocate page"
2798 "for trace buffer!\n");
2801 page = virt_to_page(array);
2802 list_add(&page->lru, &pages);
2806 /* Now that we successfully allocate a page per CPU, add them */
2807 for_each_tracing_cpu(i) {
2808 data = global_trace.data[i];
2809 page = list_entry(pages.next, struct page, lru);
2810 list_del_init(&page->lru);
2811 list_add_tail(&page->lru, &data->trace_pages);
2814 #ifdef CONFIG_TRACER_MAX_TRACE
2815 data = max_tr.data[i];
2816 page = list_entry(pages.next, struct page, lru);
2817 list_del_init(&page->lru);
2818 list_add_tail(&page->lru, &data->trace_pages);
2822 global_trace.entries += ENTRIES_PER_PAGE;
2827 list_for_each_entry_safe(page, tmp, &pages, lru) {
2828 list_del_init(&page->lru);
2834 static int trace_free_page(void)
2836 struct trace_array_cpu *data;
2838 struct list_head *p;
2842 /* free one page from each buffer */
2843 for_each_tracing_cpu(i) {
2844 data = global_trace.data[i];
2845 p = data->trace_pages.next;
2846 if (p == &data->trace_pages) {
2847 /* should never happen */
2849 tracing_disabled = 1;
2853 page = list_entry(p, struct page, lru);
2855 list_del(&page->lru);
2858 tracing_reset(data);
2860 #ifdef CONFIG_TRACER_MAX_TRACE
2861 data = max_tr.data[i];
2862 p = data->trace_pages.next;
2863 if (p == &data->trace_pages) {
2864 /* should never happen */
2866 tracing_disabled = 1;
2870 page = list_entry(p, struct page, lru);
2872 list_del(&page->lru);
2875 tracing_reset(data);
2878 global_trace.entries -= ENTRIES_PER_PAGE;
2883 __init static int tracer_alloc_buffers(void)
2885 struct trace_array_cpu *data;
2892 global_trace.ctrl = tracer_enabled;
2894 /* TODO: make the number of buffers hot pluggable with CPUS */
2895 tracing_nr_buffers = num_possible_cpus();
2896 tracing_buffer_mask = cpu_possible_map;
2898 /* Allocate the first page for all buffers */
2899 for_each_tracing_cpu(i) {
2900 data = global_trace.data[i] = &per_cpu(global_trace_cpu, i);
2901 max_tr.data[i] = &per_cpu(max_data, i);
2903 array = (void *)__get_free_page(GFP_KERNEL);
2904 if (array == NULL) {
2905 printk(KERN_ERR "tracer: failed to allocate page"
2906 "for trace buffer!\n");
2910 /* set the array to the list */
2911 INIT_LIST_HEAD(&data->trace_pages);
2912 page = virt_to_page(array);
2913 list_add(&page->lru, &data->trace_pages);
2914 /* use the LRU flag to differentiate the two buffers */
2917 data->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
2918 max_tr.data[i]->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
2920 /* Only allocate if we are actually using the max trace */
2921 #ifdef CONFIG_TRACER_MAX_TRACE
2922 array = (void *)__get_free_page(GFP_KERNEL);
2923 if (array == NULL) {
2924 printk(KERN_ERR "tracer: failed to allocate page"
2925 "for trace buffer!\n");
2929 INIT_LIST_HEAD(&max_tr.data[i]->trace_pages);
2930 page = virt_to_page(array);
2931 list_add(&page->lru, &max_tr.data[i]->trace_pages);
2937 * Since we allocate by orders of pages, we may be able to
2940 global_trace.entries = ENTRIES_PER_PAGE;
2943 while (global_trace.entries < trace_nr_entries) {
2944 if (trace_alloc_page())
2948 max_tr.entries = global_trace.entries;
2950 pr_info("tracer: %d pages allocated for %ld",
2951 pages, trace_nr_entries);
2952 pr_info(" entries of %ld bytes\n", (long)TRACE_ENTRY_SIZE);
2953 pr_info(" actual entries %ld\n", global_trace.entries);
2955 tracer_init_debugfs();
2957 trace_init_cmdlines();
2959 register_tracer(&no_tracer);
2960 current_trace = &no_tracer;
2962 /* All seems OK, enable tracing */
2963 tracing_disabled = 0;
2968 for (i-- ; i >= 0; i--) {
2969 struct page *page, *tmp;
2970 struct trace_array_cpu *data = global_trace.data[i];
2973 list_for_each_entry_safe(page, tmp,
2974 &data->trace_pages, lru) {
2975 list_del_init(&page->lru);
2980 #ifdef CONFIG_TRACER_MAX_TRACE
2981 data = max_tr.data[i];
2983 list_for_each_entry_safe(page, tmp,
2984 &data->trace_pages, lru) {
2985 list_del_init(&page->lru);
2993 fs_initcall(tracer_alloc_buffers);