2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/sysfs.h>
21 #include <linux/dcache.h>
22 #include <linux/percpu.h>
23 #include <linux/ptrace.h>
24 #include <linux/vmstat.h>
25 #include <linux/vmalloc.h>
26 #include <linux/hardirq.h>
27 #include <linux/rculist.h>
28 #include <linux/uaccess.h>
29 #include <linux/syscalls.h>
30 #include <linux/anon_inodes.h>
31 #include <linux/kernel_stat.h>
32 #include <linux/perf_event.h>
33 #include <linux/ftrace_event.h>
35 #include <asm/irq_regs.h>
37 static atomic_t nr_events __read_mostly;
38 static atomic_t nr_mmap_events __read_mostly;
39 static atomic_t nr_comm_events __read_mostly;
40 static atomic_t nr_task_events __read_mostly;
42 static LIST_HEAD(pmus);
43 static DEFINE_MUTEX(pmus_lock);
44 static struct srcu_struct pmus_srcu;
47 * perf event paranoia level:
48 * -1 - not paranoid at all
49 * 0 - disallow raw tracepoint access for unpriv
50 * 1 - disallow cpu events for unpriv
51 * 2 - disallow kernel profiling for unpriv
53 int sysctl_perf_event_paranoid __read_mostly = 1;
55 int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
58 * max perf event sample rate
60 int sysctl_perf_event_sample_rate __read_mostly = 100000;
62 static atomic64_t perf_event_id;
64 void __weak perf_event_print_debug(void) { }
66 void perf_pmu_disable(struct pmu *pmu)
68 int *count = this_cpu_ptr(pmu->pmu_disable_count);
70 pmu->pmu_disable(pmu);
73 void perf_pmu_enable(struct pmu *pmu)
75 int *count = this_cpu_ptr(pmu->pmu_disable_count);
80 static void perf_pmu_rotate_start(struct pmu *pmu)
82 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
84 if (hrtimer_active(&cpuctx->timer))
87 __hrtimer_start_range_ns(&cpuctx->timer,
88 ns_to_ktime(cpuctx->timer_interval), 0,
89 HRTIMER_MODE_REL_PINNED, 0);
92 static void perf_pmu_rotate_stop(struct pmu *pmu)
94 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
96 hrtimer_cancel(&cpuctx->timer);
99 static void get_ctx(struct perf_event_context *ctx)
101 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
104 static void free_ctx(struct rcu_head *head)
106 struct perf_event_context *ctx;
108 ctx = container_of(head, struct perf_event_context, rcu_head);
112 static void put_ctx(struct perf_event_context *ctx)
114 if (atomic_dec_and_test(&ctx->refcount)) {
116 put_ctx(ctx->parent_ctx);
118 put_task_struct(ctx->task);
119 call_rcu(&ctx->rcu_head, free_ctx);
123 static void unclone_ctx(struct perf_event_context *ctx)
125 if (ctx->parent_ctx) {
126 put_ctx(ctx->parent_ctx);
127 ctx->parent_ctx = NULL;
132 * If we inherit events we want to return the parent event id
135 static u64 primary_event_id(struct perf_event *event)
140 id = event->parent->id;
146 * Get the perf_event_context for a task and lock it.
147 * This has to cope with with the fact that until it is locked,
148 * the context could get moved to another task.
150 static struct perf_event_context *
151 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
153 struct perf_event_context *ctx;
157 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
160 * If this context is a clone of another, it might
161 * get swapped for another underneath us by
162 * perf_event_task_sched_out, though the
163 * rcu_read_lock() protects us from any context
164 * getting freed. Lock the context and check if it
165 * got swapped before we could get the lock, and retry
166 * if so. If we locked the right context, then it
167 * can't get swapped on us any more.
169 raw_spin_lock_irqsave(&ctx->lock, *flags);
170 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
171 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
175 if (!atomic_inc_not_zero(&ctx->refcount)) {
176 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
185 * Get the context for a task and increment its pin_count so it
186 * can't get swapped to another task. This also increments its
187 * reference count so that the context can't get freed.
189 static struct perf_event_context *
190 perf_pin_task_context(struct task_struct *task, int ctxn)
192 struct perf_event_context *ctx;
195 ctx = perf_lock_task_context(task, ctxn, &flags);
198 raw_spin_unlock_irqrestore(&ctx->lock, flags);
203 static void perf_unpin_context(struct perf_event_context *ctx)
207 raw_spin_lock_irqsave(&ctx->lock, flags);
209 raw_spin_unlock_irqrestore(&ctx->lock, flags);
213 static inline u64 perf_clock(void)
215 return local_clock();
219 * Update the record of the current time in a context.
221 static void update_context_time(struct perf_event_context *ctx)
223 u64 now = perf_clock();
225 ctx->time += now - ctx->timestamp;
226 ctx->timestamp = now;
230 * Update the total_time_enabled and total_time_running fields for a event.
232 static void update_event_times(struct perf_event *event)
234 struct perf_event_context *ctx = event->ctx;
237 if (event->state < PERF_EVENT_STATE_INACTIVE ||
238 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
244 run_end = event->tstamp_stopped;
246 event->total_time_enabled = run_end - event->tstamp_enabled;
248 if (event->state == PERF_EVENT_STATE_INACTIVE)
249 run_end = event->tstamp_stopped;
253 event->total_time_running = run_end - event->tstamp_running;
257 * Update total_time_enabled and total_time_running for all events in a group.
259 static void update_group_times(struct perf_event *leader)
261 struct perf_event *event;
263 update_event_times(leader);
264 list_for_each_entry(event, &leader->sibling_list, group_entry)
265 update_event_times(event);
268 static struct list_head *
269 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
271 if (event->attr.pinned)
272 return &ctx->pinned_groups;
274 return &ctx->flexible_groups;
278 * Add a event from the lists for its context.
279 * Must be called with ctx->mutex and ctx->lock held.
282 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
284 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
285 event->attach_state |= PERF_ATTACH_CONTEXT;
288 * If we're a stand alone event or group leader, we go to the context
289 * list, group events are kept attached to the group so that
290 * perf_group_detach can, at all times, locate all siblings.
292 if (event->group_leader == event) {
293 struct list_head *list;
295 if (is_software_event(event))
296 event->group_flags |= PERF_GROUP_SOFTWARE;
298 list = ctx_group_list(event, ctx);
299 list_add_tail(&event->group_entry, list);
302 list_add_rcu(&event->event_entry, &ctx->event_list);
304 perf_pmu_rotate_start(ctx->pmu);
306 if (event->attr.inherit_stat)
310 static void perf_group_attach(struct perf_event *event)
312 struct perf_event *group_leader = event->group_leader;
314 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_GROUP);
315 event->attach_state |= PERF_ATTACH_GROUP;
317 if (group_leader == event)
320 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
321 !is_software_event(event))
322 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
324 list_add_tail(&event->group_entry, &group_leader->sibling_list);
325 group_leader->nr_siblings++;
329 * Remove a event from the lists for its context.
330 * Must be called with ctx->mutex and ctx->lock held.
333 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
336 * We can have double detach due to exit/hot-unplug + close.
338 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
341 event->attach_state &= ~PERF_ATTACH_CONTEXT;
344 if (event->attr.inherit_stat)
347 list_del_rcu(&event->event_entry);
349 if (event->group_leader == event)
350 list_del_init(&event->group_entry);
352 update_group_times(event);
355 * If event was in error state, then keep it
356 * that way, otherwise bogus counts will be
357 * returned on read(). The only way to get out
358 * of error state is by explicit re-enabling
361 if (event->state > PERF_EVENT_STATE_OFF)
362 event->state = PERF_EVENT_STATE_OFF;
365 static void perf_group_detach(struct perf_event *event)
367 struct perf_event *sibling, *tmp;
368 struct list_head *list = NULL;
371 * We can have double detach due to exit/hot-unplug + close.
373 if (!(event->attach_state & PERF_ATTACH_GROUP))
376 event->attach_state &= ~PERF_ATTACH_GROUP;
379 * If this is a sibling, remove it from its group.
381 if (event->group_leader != event) {
382 list_del_init(&event->group_entry);
383 event->group_leader->nr_siblings--;
387 if (!list_empty(&event->group_entry))
388 list = &event->group_entry;
391 * If this was a group event with sibling events then
392 * upgrade the siblings to singleton events by adding them
393 * to whatever list we are on.
395 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
397 list_move_tail(&sibling->group_entry, list);
398 sibling->group_leader = sibling;
400 /* Inherit group flags from the previous leader */
401 sibling->group_flags = event->group_flags;
406 event_filter_match(struct perf_event *event)
408 return event->cpu == -1 || event->cpu == smp_processor_id();
412 event_sched_out(struct perf_event *event,
413 struct perf_cpu_context *cpuctx,
414 struct perf_event_context *ctx)
418 * An event which could not be activated because of
419 * filter mismatch still needs to have its timings
420 * maintained, otherwise bogus information is return
421 * via read() for time_enabled, time_running:
423 if (event->state == PERF_EVENT_STATE_INACTIVE
424 && !event_filter_match(event)) {
425 delta = ctx->time - event->tstamp_stopped;
426 event->tstamp_running += delta;
427 event->tstamp_stopped = ctx->time;
430 if (event->state != PERF_EVENT_STATE_ACTIVE)
433 event->state = PERF_EVENT_STATE_INACTIVE;
434 if (event->pending_disable) {
435 event->pending_disable = 0;
436 event->state = PERF_EVENT_STATE_OFF;
438 event->tstamp_stopped = ctx->time;
439 event->pmu->del(event, 0);
442 if (!is_software_event(event))
443 cpuctx->active_oncpu--;
445 if (event->attr.exclusive || !cpuctx->active_oncpu)
446 cpuctx->exclusive = 0;
450 group_sched_out(struct perf_event *group_event,
451 struct perf_cpu_context *cpuctx,
452 struct perf_event_context *ctx)
454 struct perf_event *event;
455 int state = group_event->state;
457 event_sched_out(group_event, cpuctx, ctx);
460 * Schedule out siblings (if any):
462 list_for_each_entry(event, &group_event->sibling_list, group_entry)
463 event_sched_out(event, cpuctx, ctx);
465 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
466 cpuctx->exclusive = 0;
469 static inline struct perf_cpu_context *
470 __get_cpu_context(struct perf_event_context *ctx)
472 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
476 * Cross CPU call to remove a performance event
478 * We disable the event on the hardware level first. After that we
479 * remove it from the context list.
481 static void __perf_event_remove_from_context(void *info)
483 struct perf_event *event = info;
484 struct perf_event_context *ctx = event->ctx;
485 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
488 * If this is a task context, we need to check whether it is
489 * the current task context of this cpu. If not it has been
490 * scheduled out before the smp call arrived.
492 if (ctx->task && cpuctx->task_ctx != ctx)
495 raw_spin_lock(&ctx->lock);
497 event_sched_out(event, cpuctx, ctx);
499 list_del_event(event, ctx);
501 raw_spin_unlock(&ctx->lock);
506 * Remove the event from a task's (or a CPU's) list of events.
508 * Must be called with ctx->mutex held.
510 * CPU events are removed with a smp call. For task events we only
511 * call when the task is on a CPU.
513 * If event->ctx is a cloned context, callers must make sure that
514 * every task struct that event->ctx->task could possibly point to
515 * remains valid. This is OK when called from perf_release since
516 * that only calls us on the top-level context, which can't be a clone.
517 * When called from perf_event_exit_task, it's OK because the
518 * context has been detached from its task.
520 static void perf_event_remove_from_context(struct perf_event *event)
522 struct perf_event_context *ctx = event->ctx;
523 struct task_struct *task = ctx->task;
527 * Per cpu events are removed via an smp call and
528 * the removal is always successful.
530 smp_call_function_single(event->cpu,
531 __perf_event_remove_from_context,
537 task_oncpu_function_call(task, __perf_event_remove_from_context,
540 raw_spin_lock_irq(&ctx->lock);
542 * If the context is active we need to retry the smp call.
544 if (ctx->nr_active && !list_empty(&event->group_entry)) {
545 raw_spin_unlock_irq(&ctx->lock);
550 * The lock prevents that this context is scheduled in so we
551 * can remove the event safely, if the call above did not
554 if (!list_empty(&event->group_entry))
555 list_del_event(event, ctx);
556 raw_spin_unlock_irq(&ctx->lock);
560 * Cross CPU call to disable a performance event
562 static void __perf_event_disable(void *info)
564 struct perf_event *event = info;
565 struct perf_event_context *ctx = event->ctx;
566 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
569 * If this is a per-task event, need to check whether this
570 * event's task is the current task on this cpu.
572 if (ctx->task && cpuctx->task_ctx != ctx)
575 raw_spin_lock(&ctx->lock);
578 * If the event is on, turn it off.
579 * If it is in error state, leave it in error state.
581 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
582 update_context_time(ctx);
583 update_group_times(event);
584 if (event == event->group_leader)
585 group_sched_out(event, cpuctx, ctx);
587 event_sched_out(event, cpuctx, ctx);
588 event->state = PERF_EVENT_STATE_OFF;
591 raw_spin_unlock(&ctx->lock);
597 * If event->ctx is a cloned context, callers must make sure that
598 * every task struct that event->ctx->task could possibly point to
599 * remains valid. This condition is satisifed when called through
600 * perf_event_for_each_child or perf_event_for_each because they
601 * hold the top-level event's child_mutex, so any descendant that
602 * goes to exit will block in sync_child_event.
603 * When called from perf_pending_event it's OK because event->ctx
604 * is the current context on this CPU and preemption is disabled,
605 * hence we can't get into perf_event_task_sched_out for this context.
607 void perf_event_disable(struct perf_event *event)
609 struct perf_event_context *ctx = event->ctx;
610 struct task_struct *task = ctx->task;
614 * Disable the event on the cpu that it's on
616 smp_call_function_single(event->cpu, __perf_event_disable,
622 task_oncpu_function_call(task, __perf_event_disable, event);
624 raw_spin_lock_irq(&ctx->lock);
626 * If the event is still active, we need to retry the cross-call.
628 if (event->state == PERF_EVENT_STATE_ACTIVE) {
629 raw_spin_unlock_irq(&ctx->lock);
634 * Since we have the lock this context can't be scheduled
635 * in, so we can change the state safely.
637 if (event->state == PERF_EVENT_STATE_INACTIVE) {
638 update_group_times(event);
639 event->state = PERF_EVENT_STATE_OFF;
642 raw_spin_unlock_irq(&ctx->lock);
646 event_sched_in(struct perf_event *event,
647 struct perf_cpu_context *cpuctx,
648 struct perf_event_context *ctx)
650 if (event->state <= PERF_EVENT_STATE_OFF)
653 event->state = PERF_EVENT_STATE_ACTIVE;
654 event->oncpu = smp_processor_id();
656 * The new state must be visible before we turn it on in the hardware:
660 if (event->pmu->add(event, PERF_EF_START)) {
661 event->state = PERF_EVENT_STATE_INACTIVE;
666 event->tstamp_running += ctx->time - event->tstamp_stopped;
668 if (!is_software_event(event))
669 cpuctx->active_oncpu++;
672 if (event->attr.exclusive)
673 cpuctx->exclusive = 1;
679 group_sched_in(struct perf_event *group_event,
680 struct perf_cpu_context *cpuctx,
681 struct perf_event_context *ctx)
683 struct perf_event *event, *partial_group = NULL;
684 struct pmu *pmu = group_event->pmu;
686 if (group_event->state == PERF_EVENT_STATE_OFF)
691 if (event_sched_in(group_event, cpuctx, ctx)) {
692 pmu->cancel_txn(pmu);
697 * Schedule in siblings as one group (if any):
699 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
700 if (event_sched_in(event, cpuctx, ctx)) {
701 partial_group = event;
706 if (!pmu->commit_txn(pmu))
711 * Groups can be scheduled in as one unit only, so undo any
712 * partial group before returning:
714 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
715 if (event == partial_group)
717 event_sched_out(event, cpuctx, ctx);
719 event_sched_out(group_event, cpuctx, ctx);
721 pmu->cancel_txn(pmu);
727 * Work out whether we can put this event group on the CPU now.
729 static int group_can_go_on(struct perf_event *event,
730 struct perf_cpu_context *cpuctx,
734 * Groups consisting entirely of software events can always go on.
736 if (event->group_flags & PERF_GROUP_SOFTWARE)
739 * If an exclusive group is already on, no other hardware
742 if (cpuctx->exclusive)
745 * If this group is exclusive and there are already
746 * events on the CPU, it can't go on.
748 if (event->attr.exclusive && cpuctx->active_oncpu)
751 * Otherwise, try to add it if all previous groups were able
757 static void add_event_to_ctx(struct perf_event *event,
758 struct perf_event_context *ctx)
760 list_add_event(event, ctx);
761 perf_group_attach(event);
762 event->tstamp_enabled = ctx->time;
763 event->tstamp_running = ctx->time;
764 event->tstamp_stopped = ctx->time;
768 * Cross CPU call to install and enable a performance event
770 * Must be called with ctx->mutex held
772 static void __perf_install_in_context(void *info)
774 struct perf_event *event = info;
775 struct perf_event_context *ctx = event->ctx;
776 struct perf_event *leader = event->group_leader;
777 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
781 * If this is a task context, we need to check whether it is
782 * the current task context of this cpu. If not it has been
783 * scheduled out before the smp call arrived.
784 * Or possibly this is the right context but it isn't
785 * on this cpu because it had no events.
787 if (ctx->task && cpuctx->task_ctx != ctx) {
788 if (cpuctx->task_ctx || ctx->task != current)
790 cpuctx->task_ctx = ctx;
793 raw_spin_lock(&ctx->lock);
795 update_context_time(ctx);
797 add_event_to_ctx(event, ctx);
799 if (event->cpu != -1 && event->cpu != smp_processor_id())
803 * Don't put the event on if it is disabled or if
804 * it is in a group and the group isn't on.
806 if (event->state != PERF_EVENT_STATE_INACTIVE ||
807 (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
811 * An exclusive event can't go on if there are already active
812 * hardware events, and no hardware event can go on if there
813 * is already an exclusive event on.
815 if (!group_can_go_on(event, cpuctx, 1))
818 err = event_sched_in(event, cpuctx, ctx);
822 * This event couldn't go on. If it is in a group
823 * then we have to pull the whole group off.
824 * If the event group is pinned then put it in error state.
827 group_sched_out(leader, cpuctx, ctx);
828 if (leader->attr.pinned) {
829 update_group_times(leader);
830 leader->state = PERF_EVENT_STATE_ERROR;
835 raw_spin_unlock(&ctx->lock);
839 * Attach a performance event to a context
841 * First we add the event to the list with the hardware enable bit
842 * in event->hw_config cleared.
844 * If the event is attached to a task which is on a CPU we use a smp
845 * call to enable it in the task context. The task might have been
846 * scheduled away, but we check this in the smp call again.
848 * Must be called with ctx->mutex held.
851 perf_install_in_context(struct perf_event_context *ctx,
852 struct perf_event *event,
855 struct task_struct *task = ctx->task;
861 * Per cpu events are installed via an smp call and
862 * the install is always successful.
864 smp_call_function_single(cpu, __perf_install_in_context,
870 task_oncpu_function_call(task, __perf_install_in_context,
873 raw_spin_lock_irq(&ctx->lock);
875 * we need to retry the smp call.
877 if (ctx->is_active && list_empty(&event->group_entry)) {
878 raw_spin_unlock_irq(&ctx->lock);
883 * The lock prevents that this context is scheduled in so we
884 * can add the event safely, if it the call above did not
887 if (list_empty(&event->group_entry))
888 add_event_to_ctx(event, ctx);
889 raw_spin_unlock_irq(&ctx->lock);
893 * Put a event into inactive state and update time fields.
894 * Enabling the leader of a group effectively enables all
895 * the group members that aren't explicitly disabled, so we
896 * have to update their ->tstamp_enabled also.
897 * Note: this works for group members as well as group leaders
898 * since the non-leader members' sibling_lists will be empty.
900 static void __perf_event_mark_enabled(struct perf_event *event,
901 struct perf_event_context *ctx)
903 struct perf_event *sub;
905 event->state = PERF_EVENT_STATE_INACTIVE;
906 event->tstamp_enabled = ctx->time - event->total_time_enabled;
907 list_for_each_entry(sub, &event->sibling_list, group_entry) {
908 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
909 sub->tstamp_enabled =
910 ctx->time - sub->total_time_enabled;
916 * Cross CPU call to enable a performance event
918 static void __perf_event_enable(void *info)
920 struct perf_event *event = info;
921 struct perf_event_context *ctx = event->ctx;
922 struct perf_event *leader = event->group_leader;
923 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
927 * If this is a per-task event, need to check whether this
928 * event's task is the current task on this cpu.
930 if (ctx->task && cpuctx->task_ctx != ctx) {
931 if (cpuctx->task_ctx || ctx->task != current)
933 cpuctx->task_ctx = ctx;
936 raw_spin_lock(&ctx->lock);
938 update_context_time(ctx);
940 if (event->state >= PERF_EVENT_STATE_INACTIVE)
942 __perf_event_mark_enabled(event, ctx);
944 if (event->cpu != -1 && event->cpu != smp_processor_id())
948 * If the event is in a group and isn't the group leader,
949 * then don't put it on unless the group is on.
951 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
954 if (!group_can_go_on(event, cpuctx, 1)) {
958 err = group_sched_in(event, cpuctx, ctx);
960 err = event_sched_in(event, cpuctx, ctx);
965 * If this event can't go on and it's part of a
966 * group, then the whole group has to come off.
969 group_sched_out(leader, cpuctx, ctx);
970 if (leader->attr.pinned) {
971 update_group_times(leader);
972 leader->state = PERF_EVENT_STATE_ERROR;
977 raw_spin_unlock(&ctx->lock);
983 * If event->ctx is a cloned context, callers must make sure that
984 * every task struct that event->ctx->task could possibly point to
985 * remains valid. This condition is satisfied when called through
986 * perf_event_for_each_child or perf_event_for_each as described
987 * for perf_event_disable.
989 void perf_event_enable(struct perf_event *event)
991 struct perf_event_context *ctx = event->ctx;
992 struct task_struct *task = ctx->task;
996 * Enable the event on the cpu that it's on
998 smp_call_function_single(event->cpu, __perf_event_enable,
1003 raw_spin_lock_irq(&ctx->lock);
1004 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1008 * If the event is in error state, clear that first.
1009 * That way, if we see the event in error state below, we
1010 * know that it has gone back into error state, as distinct
1011 * from the task having been scheduled away before the
1012 * cross-call arrived.
1014 if (event->state == PERF_EVENT_STATE_ERROR)
1015 event->state = PERF_EVENT_STATE_OFF;
1018 raw_spin_unlock_irq(&ctx->lock);
1019 task_oncpu_function_call(task, __perf_event_enable, event);
1021 raw_spin_lock_irq(&ctx->lock);
1024 * If the context is active and the event is still off,
1025 * we need to retry the cross-call.
1027 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF)
1031 * Since we have the lock this context can't be scheduled
1032 * in, so we can change the state safely.
1034 if (event->state == PERF_EVENT_STATE_OFF)
1035 __perf_event_mark_enabled(event, ctx);
1038 raw_spin_unlock_irq(&ctx->lock);
1041 static int perf_event_refresh(struct perf_event *event, int refresh)
1044 * not supported on inherited events
1046 if (event->attr.inherit)
1049 atomic_add(refresh, &event->event_limit);
1050 perf_event_enable(event);
1056 EVENT_FLEXIBLE = 0x1,
1058 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
1061 static void ctx_sched_out(struct perf_event_context *ctx,
1062 struct perf_cpu_context *cpuctx,
1063 enum event_type_t event_type)
1065 struct perf_event *event;
1067 raw_spin_lock(&ctx->lock);
1068 perf_pmu_disable(ctx->pmu);
1070 if (likely(!ctx->nr_events))
1072 update_context_time(ctx);
1074 if (!ctx->nr_active)
1077 if (event_type & EVENT_PINNED) {
1078 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
1079 group_sched_out(event, cpuctx, ctx);
1082 if (event_type & EVENT_FLEXIBLE) {
1083 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
1084 group_sched_out(event, cpuctx, ctx);
1087 perf_pmu_enable(ctx->pmu);
1088 raw_spin_unlock(&ctx->lock);
1092 * Test whether two contexts are equivalent, i.e. whether they
1093 * have both been cloned from the same version of the same context
1094 * and they both have the same number of enabled events.
1095 * If the number of enabled events is the same, then the set
1096 * of enabled events should be the same, because these are both
1097 * inherited contexts, therefore we can't access individual events
1098 * in them directly with an fd; we can only enable/disable all
1099 * events via prctl, or enable/disable all events in a family
1100 * via ioctl, which will have the same effect on both contexts.
1102 static int context_equiv(struct perf_event_context *ctx1,
1103 struct perf_event_context *ctx2)
1105 return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
1106 && ctx1->parent_gen == ctx2->parent_gen
1107 && !ctx1->pin_count && !ctx2->pin_count;
1110 static void __perf_event_sync_stat(struct perf_event *event,
1111 struct perf_event *next_event)
1115 if (!event->attr.inherit_stat)
1119 * Update the event value, we cannot use perf_event_read()
1120 * because we're in the middle of a context switch and have IRQs
1121 * disabled, which upsets smp_call_function_single(), however
1122 * we know the event must be on the current CPU, therefore we
1123 * don't need to use it.
1125 switch (event->state) {
1126 case PERF_EVENT_STATE_ACTIVE:
1127 event->pmu->read(event);
1130 case PERF_EVENT_STATE_INACTIVE:
1131 update_event_times(event);
1139 * In order to keep per-task stats reliable we need to flip the event
1140 * values when we flip the contexts.
1142 value = local64_read(&next_event->count);
1143 value = local64_xchg(&event->count, value);
1144 local64_set(&next_event->count, value);
1146 swap(event->total_time_enabled, next_event->total_time_enabled);
1147 swap(event->total_time_running, next_event->total_time_running);
1150 * Since we swizzled the values, update the user visible data too.
1152 perf_event_update_userpage(event);
1153 perf_event_update_userpage(next_event);
1156 #define list_next_entry(pos, member) \
1157 list_entry(pos->member.next, typeof(*pos), member)
1159 static void perf_event_sync_stat(struct perf_event_context *ctx,
1160 struct perf_event_context *next_ctx)
1162 struct perf_event *event, *next_event;
1167 update_context_time(ctx);
1169 event = list_first_entry(&ctx->event_list,
1170 struct perf_event, event_entry);
1172 next_event = list_first_entry(&next_ctx->event_list,
1173 struct perf_event, event_entry);
1175 while (&event->event_entry != &ctx->event_list &&
1176 &next_event->event_entry != &next_ctx->event_list) {
1178 __perf_event_sync_stat(event, next_event);
1180 event = list_next_entry(event, event_entry);
1181 next_event = list_next_entry(next_event, event_entry);
1185 void perf_event_context_sched_out(struct task_struct *task, int ctxn,
1186 struct task_struct *next)
1188 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
1189 struct perf_event_context *next_ctx;
1190 struct perf_event_context *parent;
1191 struct perf_cpu_context *cpuctx;
1197 cpuctx = __get_cpu_context(ctx);
1198 if (!cpuctx->task_ctx)
1202 parent = rcu_dereference(ctx->parent_ctx);
1203 next_ctx = next->perf_event_ctxp[ctxn];
1204 if (parent && next_ctx &&
1205 rcu_dereference(next_ctx->parent_ctx) == parent) {
1207 * Looks like the two contexts are clones, so we might be
1208 * able to optimize the context switch. We lock both
1209 * contexts and check that they are clones under the
1210 * lock (including re-checking that neither has been
1211 * uncloned in the meantime). It doesn't matter which
1212 * order we take the locks because no other cpu could
1213 * be trying to lock both of these tasks.
1215 raw_spin_lock(&ctx->lock);
1216 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
1217 if (context_equiv(ctx, next_ctx)) {
1219 * XXX do we need a memory barrier of sorts
1220 * wrt to rcu_dereference() of perf_event_ctxp
1222 task->perf_event_ctxp[ctxn] = next_ctx;
1223 next->perf_event_ctxp[ctxn] = ctx;
1225 next_ctx->task = task;
1228 perf_event_sync_stat(ctx, next_ctx);
1230 raw_spin_unlock(&next_ctx->lock);
1231 raw_spin_unlock(&ctx->lock);
1236 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
1237 cpuctx->task_ctx = NULL;
1241 #define for_each_task_context_nr(ctxn) \
1242 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
1245 * Called from scheduler to remove the events of the current task,
1246 * with interrupts disabled.
1248 * We stop each event and update the event value in event->count.
1250 * This does not protect us against NMI, but disable()
1251 * sets the disabled bit in the control field of event _before_
1252 * accessing the event control register. If a NMI hits, then it will
1253 * not restart the event.
1255 void perf_event_task_sched_out(struct task_struct *task,
1256 struct task_struct *next)
1260 perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);
1262 for_each_task_context_nr(ctxn)
1263 perf_event_context_sched_out(task, ctxn, next);
1266 static void task_ctx_sched_out(struct perf_event_context *ctx,
1267 enum event_type_t event_type)
1269 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1271 if (!cpuctx->task_ctx)
1274 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
1277 ctx_sched_out(ctx, cpuctx, event_type);
1278 cpuctx->task_ctx = NULL;
1282 * Called with IRQs disabled
1284 static void __perf_event_task_sched_out(struct perf_event_context *ctx)
1286 task_ctx_sched_out(ctx, EVENT_ALL);
1290 * Called with IRQs disabled
1292 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
1293 enum event_type_t event_type)
1295 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
1299 ctx_pinned_sched_in(struct perf_event_context *ctx,
1300 struct perf_cpu_context *cpuctx)
1302 struct perf_event *event;
1304 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1305 if (event->state <= PERF_EVENT_STATE_OFF)
1307 if (event->cpu != -1 && event->cpu != smp_processor_id())
1310 if (group_can_go_on(event, cpuctx, 1))
1311 group_sched_in(event, cpuctx, ctx);
1314 * If this pinned group hasn't been scheduled,
1315 * put it in error state.
1317 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1318 update_group_times(event);
1319 event->state = PERF_EVENT_STATE_ERROR;
1325 ctx_flexible_sched_in(struct perf_event_context *ctx,
1326 struct perf_cpu_context *cpuctx)
1328 struct perf_event *event;
1331 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1332 /* Ignore events in OFF or ERROR state */
1333 if (event->state <= PERF_EVENT_STATE_OFF)
1336 * Listen to the 'cpu' scheduling filter constraint
1339 if (event->cpu != -1 && event->cpu != smp_processor_id())
1342 if (group_can_go_on(event, cpuctx, can_add_hw)) {
1343 if (group_sched_in(event, cpuctx, ctx))
1350 ctx_sched_in(struct perf_event_context *ctx,
1351 struct perf_cpu_context *cpuctx,
1352 enum event_type_t event_type)
1354 raw_spin_lock(&ctx->lock);
1356 if (likely(!ctx->nr_events))
1359 ctx->timestamp = perf_clock();
1362 * First go through the list and put on any pinned groups
1363 * in order to give them the best chance of going on.
1365 if (event_type & EVENT_PINNED)
1366 ctx_pinned_sched_in(ctx, cpuctx);
1368 /* Then walk through the lower prio flexible groups */
1369 if (event_type & EVENT_FLEXIBLE)
1370 ctx_flexible_sched_in(ctx, cpuctx);
1373 raw_spin_unlock(&ctx->lock);
1376 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
1377 enum event_type_t event_type)
1379 struct perf_event_context *ctx = &cpuctx->ctx;
1381 ctx_sched_in(ctx, cpuctx, event_type);
1384 static void task_ctx_sched_in(struct perf_event_context *ctx,
1385 enum event_type_t event_type)
1387 struct perf_cpu_context *cpuctx;
1389 cpuctx = __get_cpu_context(ctx);
1390 if (cpuctx->task_ctx == ctx)
1393 ctx_sched_in(ctx, cpuctx, event_type);
1394 cpuctx->task_ctx = ctx;
1397 void perf_event_context_sched_in(struct perf_event_context *ctx)
1399 struct perf_cpu_context *cpuctx;
1401 cpuctx = __get_cpu_context(ctx);
1402 if (cpuctx->task_ctx == ctx)
1405 perf_pmu_disable(ctx->pmu);
1407 * We want to keep the following priority order:
1408 * cpu pinned (that don't need to move), task pinned,
1409 * cpu flexible, task flexible.
1411 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1413 ctx_sched_in(ctx, cpuctx, EVENT_PINNED);
1414 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1415 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE);
1417 cpuctx->task_ctx = ctx;
1420 * Since these rotations are per-cpu, we need to ensure the
1421 * cpu-context we got scheduled on is actually rotating.
1423 perf_pmu_rotate_start(ctx->pmu);
1424 perf_pmu_enable(ctx->pmu);
1428 * Called from scheduler to add the events of the current task
1429 * with interrupts disabled.
1431 * We restore the event value and then enable it.
1433 * This does not protect us against NMI, but enable()
1434 * sets the enabled bit in the control field of event _before_
1435 * accessing the event control register. If a NMI hits, then it will
1436 * keep the event running.
1438 void perf_event_task_sched_in(struct task_struct *task)
1440 struct perf_event_context *ctx;
1443 for_each_task_context_nr(ctxn) {
1444 ctx = task->perf_event_ctxp[ctxn];
1448 perf_event_context_sched_in(ctx);
1452 #define MAX_INTERRUPTS (~0ULL)
1454 static void perf_log_throttle(struct perf_event *event, int enable);
1456 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
1458 u64 frequency = event->attr.sample_freq;
1459 u64 sec = NSEC_PER_SEC;
1460 u64 divisor, dividend;
1462 int count_fls, nsec_fls, frequency_fls, sec_fls;
1464 count_fls = fls64(count);
1465 nsec_fls = fls64(nsec);
1466 frequency_fls = fls64(frequency);
1470 * We got @count in @nsec, with a target of sample_freq HZ
1471 * the target period becomes:
1474 * period = -------------------
1475 * @nsec * sample_freq
1480 * Reduce accuracy by one bit such that @a and @b converge
1481 * to a similar magnitude.
1483 #define REDUCE_FLS(a, b) \
1485 if (a##_fls > b##_fls) { \
1495 * Reduce accuracy until either term fits in a u64, then proceed with
1496 * the other, so that finally we can do a u64/u64 division.
1498 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
1499 REDUCE_FLS(nsec, frequency);
1500 REDUCE_FLS(sec, count);
1503 if (count_fls + sec_fls > 64) {
1504 divisor = nsec * frequency;
1506 while (count_fls + sec_fls > 64) {
1507 REDUCE_FLS(count, sec);
1511 dividend = count * sec;
1513 dividend = count * sec;
1515 while (nsec_fls + frequency_fls > 64) {
1516 REDUCE_FLS(nsec, frequency);
1520 divisor = nsec * frequency;
1526 return div64_u64(dividend, divisor);
1529 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
1531 struct hw_perf_event *hwc = &event->hw;
1532 s64 period, sample_period;
1535 period = perf_calculate_period(event, nsec, count);
1537 delta = (s64)(period - hwc->sample_period);
1538 delta = (delta + 7) / 8; /* low pass filter */
1540 sample_period = hwc->sample_period + delta;
1545 hwc->sample_period = sample_period;
1547 if (local64_read(&hwc->period_left) > 8*sample_period) {
1548 event->pmu->stop(event, PERF_EF_UPDATE);
1549 local64_set(&hwc->period_left, 0);
1550 event->pmu->start(event, PERF_EF_RELOAD);
1554 static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
1556 struct perf_event *event;
1557 struct hw_perf_event *hwc;
1558 u64 interrupts, now;
1561 raw_spin_lock(&ctx->lock);
1562 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
1563 if (event->state != PERF_EVENT_STATE_ACTIVE)
1566 if (event->cpu != -1 && event->cpu != smp_processor_id())
1571 interrupts = hwc->interrupts;
1572 hwc->interrupts = 0;
1575 * unthrottle events on the tick
1577 if (interrupts == MAX_INTERRUPTS) {
1578 perf_log_throttle(event, 1);
1579 event->pmu->start(event, 0);
1582 if (!event->attr.freq || !event->attr.sample_freq)
1585 event->pmu->read(event);
1586 now = local64_read(&event->count);
1587 delta = now - hwc->freq_count_stamp;
1588 hwc->freq_count_stamp = now;
1591 perf_adjust_period(event, period, delta);
1593 raw_spin_unlock(&ctx->lock);
1597 * Round-robin a context's events:
1599 static void rotate_ctx(struct perf_event_context *ctx)
1601 raw_spin_lock(&ctx->lock);
1603 /* Rotate the first entry last of non-pinned groups */
1604 list_rotate_left(&ctx->flexible_groups);
1606 raw_spin_unlock(&ctx->lock);
1610 * Cannot race with ->pmu_rotate_start() because this is ran from hardirq
1611 * context, and ->pmu_rotate_start() is called with irqs disabled (both are
1612 * cpu affine, so there are no SMP races).
1614 static enum hrtimer_restart perf_event_context_tick(struct hrtimer *timer)
1616 enum hrtimer_restart restart = HRTIMER_NORESTART;
1617 struct perf_cpu_context *cpuctx;
1618 struct perf_event_context *ctx = NULL;
1621 cpuctx = container_of(timer, struct perf_cpu_context, timer);
1623 if (cpuctx->ctx.nr_events) {
1624 restart = HRTIMER_RESTART;
1625 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
1629 ctx = cpuctx->task_ctx;
1630 if (ctx && ctx->nr_events) {
1631 restart = HRTIMER_RESTART;
1632 if (ctx->nr_events != ctx->nr_active)
1636 perf_pmu_disable(cpuctx->ctx.pmu);
1637 perf_ctx_adjust_freq(&cpuctx->ctx, cpuctx->timer_interval);
1639 perf_ctx_adjust_freq(ctx, cpuctx->timer_interval);
1644 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1646 task_ctx_sched_out(ctx, EVENT_FLEXIBLE);
1648 rotate_ctx(&cpuctx->ctx);
1652 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1654 task_ctx_sched_in(ctx, EVENT_FLEXIBLE);
1657 perf_pmu_enable(cpuctx->ctx.pmu);
1658 hrtimer_forward_now(timer, ns_to_ktime(cpuctx->timer_interval));
1663 static int event_enable_on_exec(struct perf_event *event,
1664 struct perf_event_context *ctx)
1666 if (!event->attr.enable_on_exec)
1669 event->attr.enable_on_exec = 0;
1670 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1673 __perf_event_mark_enabled(event, ctx);
1679 * Enable all of a task's events that have been marked enable-on-exec.
1680 * This expects task == current.
1682 static void perf_event_enable_on_exec(struct perf_event_context *ctx)
1684 struct perf_event *event;
1685 unsigned long flags;
1689 local_irq_save(flags);
1690 if (!ctx || !ctx->nr_events)
1693 task_ctx_sched_out(ctx, EVENT_ALL);
1695 raw_spin_lock(&ctx->lock);
1697 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1698 ret = event_enable_on_exec(event, ctx);
1703 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1704 ret = event_enable_on_exec(event, ctx);
1710 * Unclone this context if we enabled any event.
1715 raw_spin_unlock(&ctx->lock);
1717 perf_event_context_sched_in(ctx);
1719 local_irq_restore(flags);
1723 * Cross CPU call to read the hardware event
1725 static void __perf_event_read(void *info)
1727 struct perf_event *event = info;
1728 struct perf_event_context *ctx = event->ctx;
1729 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1732 * If this is a task context, we need to check whether it is
1733 * the current task context of this cpu. If not it has been
1734 * scheduled out before the smp call arrived. In that case
1735 * event->count would have been updated to a recent sample
1736 * when the event was scheduled out.
1738 if (ctx->task && cpuctx->task_ctx != ctx)
1741 raw_spin_lock(&ctx->lock);
1742 update_context_time(ctx);
1743 update_event_times(event);
1744 raw_spin_unlock(&ctx->lock);
1746 event->pmu->read(event);
1749 static inline u64 perf_event_count(struct perf_event *event)
1751 return local64_read(&event->count) + atomic64_read(&event->child_count);
1754 static u64 perf_event_read(struct perf_event *event)
1757 * If event is enabled and currently active on a CPU, update the
1758 * value in the event structure:
1760 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1761 smp_call_function_single(event->oncpu,
1762 __perf_event_read, event, 1);
1763 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
1764 struct perf_event_context *ctx = event->ctx;
1765 unsigned long flags;
1767 raw_spin_lock_irqsave(&ctx->lock, flags);
1768 update_context_time(ctx);
1769 update_event_times(event);
1770 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1773 return perf_event_count(event);
1780 struct callchain_cpus_entries {
1781 struct rcu_head rcu_head;
1782 struct perf_callchain_entry *cpu_entries[0];
1785 static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]);
1786 static atomic_t nr_callchain_events;
1787 static DEFINE_MUTEX(callchain_mutex);
1788 struct callchain_cpus_entries *callchain_cpus_entries;
1791 __weak void perf_callchain_kernel(struct perf_callchain_entry *entry,
1792 struct pt_regs *regs)
1796 __weak void perf_callchain_user(struct perf_callchain_entry *entry,
1797 struct pt_regs *regs)
1801 static void release_callchain_buffers_rcu(struct rcu_head *head)
1803 struct callchain_cpus_entries *entries;
1806 entries = container_of(head, struct callchain_cpus_entries, rcu_head);
1808 for_each_possible_cpu(cpu)
1809 kfree(entries->cpu_entries[cpu]);
1814 static void release_callchain_buffers(void)
1816 struct callchain_cpus_entries *entries;
1818 entries = callchain_cpus_entries;
1819 rcu_assign_pointer(callchain_cpus_entries, NULL);
1820 call_rcu(&entries->rcu_head, release_callchain_buffers_rcu);
1823 static int alloc_callchain_buffers(void)
1827 struct callchain_cpus_entries *entries;
1830 * We can't use the percpu allocation API for data that can be
1831 * accessed from NMI. Use a temporary manual per cpu allocation
1832 * until that gets sorted out.
1834 size = sizeof(*entries) + sizeof(struct perf_callchain_entry *) *
1835 num_possible_cpus();
1837 entries = kzalloc(size, GFP_KERNEL);
1841 size = sizeof(struct perf_callchain_entry) * PERF_NR_CONTEXTS;
1843 for_each_possible_cpu(cpu) {
1844 entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL,
1846 if (!entries->cpu_entries[cpu])
1850 rcu_assign_pointer(callchain_cpus_entries, entries);
1855 for_each_possible_cpu(cpu)
1856 kfree(entries->cpu_entries[cpu]);
1862 static int get_callchain_buffers(void)
1867 mutex_lock(&callchain_mutex);
1869 count = atomic_inc_return(&nr_callchain_events);
1870 if (WARN_ON_ONCE(count < 1)) {
1876 /* If the allocation failed, give up */
1877 if (!callchain_cpus_entries)
1882 err = alloc_callchain_buffers();
1884 release_callchain_buffers();
1886 mutex_unlock(&callchain_mutex);
1891 static void put_callchain_buffers(void)
1893 if (atomic_dec_and_mutex_lock(&nr_callchain_events, &callchain_mutex)) {
1894 release_callchain_buffers();
1895 mutex_unlock(&callchain_mutex);
1899 static int get_recursion_context(int *recursion)
1907 else if (in_softirq())
1912 if (recursion[rctx])
1921 static inline void put_recursion_context(int *recursion, int rctx)
1927 static struct perf_callchain_entry *get_callchain_entry(int *rctx)
1930 struct callchain_cpus_entries *entries;
1932 *rctx = get_recursion_context(__get_cpu_var(callchain_recursion));
1936 entries = rcu_dereference(callchain_cpus_entries);
1940 cpu = smp_processor_id();
1942 return &entries->cpu_entries[cpu][*rctx];
1946 put_callchain_entry(int rctx)
1948 put_recursion_context(__get_cpu_var(callchain_recursion), rctx);
1951 static struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
1954 struct perf_callchain_entry *entry;
1957 entry = get_callchain_entry(&rctx);
1966 if (!user_mode(regs)) {
1967 perf_callchain_store(entry, PERF_CONTEXT_KERNEL);
1968 perf_callchain_kernel(entry, regs);
1970 regs = task_pt_regs(current);
1976 perf_callchain_store(entry, PERF_CONTEXT_USER);
1977 perf_callchain_user(entry, regs);
1981 put_callchain_entry(rctx);
1987 * Initialize the perf_event context in a task_struct:
1989 static void __perf_event_init_context(struct perf_event_context *ctx)
1991 raw_spin_lock_init(&ctx->lock);
1992 mutex_init(&ctx->mutex);
1993 INIT_LIST_HEAD(&ctx->pinned_groups);
1994 INIT_LIST_HEAD(&ctx->flexible_groups);
1995 INIT_LIST_HEAD(&ctx->event_list);
1996 atomic_set(&ctx->refcount, 1);
1999 static struct perf_event_context *
2000 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
2002 struct perf_event_context *ctx;
2004 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
2008 __perf_event_init_context(ctx);
2011 get_task_struct(task);
2018 static struct perf_event_context *
2019 find_get_context(struct pmu *pmu, pid_t pid, int cpu)
2021 struct perf_event_context *ctx;
2022 struct perf_cpu_context *cpuctx;
2023 struct task_struct *task;
2024 unsigned long flags;
2027 if (pid == -1 && cpu != -1) {
2028 /* Must be root to operate on a CPU event: */
2029 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
2030 return ERR_PTR(-EACCES);
2032 if (cpu < 0 || cpu >= nr_cpumask_bits)
2033 return ERR_PTR(-EINVAL);
2036 * We could be clever and allow to attach a event to an
2037 * offline CPU and activate it when the CPU comes up, but
2040 if (!cpu_online(cpu))
2041 return ERR_PTR(-ENODEV);
2043 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
2054 task = find_task_by_vpid(pid);
2056 get_task_struct(task);
2060 return ERR_PTR(-ESRCH);
2063 * Can't attach events to a dying task.
2066 if (task->flags & PF_EXITING)
2069 /* Reuse ptrace permission checks for now. */
2071 if (!ptrace_may_access(task, PTRACE_MODE_READ))
2075 ctxn = pmu->task_ctx_nr;
2080 ctx = perf_lock_task_context(task, ctxn, &flags);
2083 raw_spin_unlock_irqrestore(&ctx->lock, flags);
2087 ctx = alloc_perf_context(pmu, task);
2094 if (cmpxchg(&task->perf_event_ctxp[ctxn], NULL, ctx)) {
2096 * We raced with some other task; use
2097 * the context they set.
2099 put_task_struct(task);
2105 put_task_struct(task);
2109 put_task_struct(task);
2110 return ERR_PTR(err);
2113 static void perf_event_free_filter(struct perf_event *event);
2115 static void free_event_rcu(struct rcu_head *head)
2117 struct perf_event *event;
2119 event = container_of(head, struct perf_event, rcu_head);
2121 put_pid_ns(event->ns);
2122 perf_event_free_filter(event);
2126 static void perf_pending_sync(struct perf_event *event);
2127 static void perf_buffer_put(struct perf_buffer *buffer);
2129 static void free_event(struct perf_event *event)
2131 perf_pending_sync(event);
2133 if (!event->parent) {
2134 atomic_dec(&nr_events);
2135 if (event->attr.mmap || event->attr.mmap_data)
2136 atomic_dec(&nr_mmap_events);
2137 if (event->attr.comm)
2138 atomic_dec(&nr_comm_events);
2139 if (event->attr.task)
2140 atomic_dec(&nr_task_events);
2141 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
2142 put_callchain_buffers();
2145 if (event->buffer) {
2146 perf_buffer_put(event->buffer);
2147 event->buffer = NULL;
2151 event->destroy(event);
2153 put_ctx(event->ctx);
2154 call_rcu(&event->rcu_head, free_event_rcu);
2157 int perf_event_release_kernel(struct perf_event *event)
2159 struct perf_event_context *ctx = event->ctx;
2162 * Remove from the PMU, can't get re-enabled since we got
2163 * here because the last ref went.
2165 perf_event_disable(event);
2167 WARN_ON_ONCE(ctx->parent_ctx);
2169 * There are two ways this annotation is useful:
2171 * 1) there is a lock recursion from perf_event_exit_task
2172 * see the comment there.
2174 * 2) there is a lock-inversion with mmap_sem through
2175 * perf_event_read_group(), which takes faults while
2176 * holding ctx->mutex, however this is called after
2177 * the last filedesc died, so there is no possibility
2178 * to trigger the AB-BA case.
2180 mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
2181 raw_spin_lock_irq(&ctx->lock);
2182 perf_group_detach(event);
2183 list_del_event(event, ctx);
2184 raw_spin_unlock_irq(&ctx->lock);
2185 mutex_unlock(&ctx->mutex);
2187 mutex_lock(&event->owner->perf_event_mutex);
2188 list_del_init(&event->owner_entry);
2189 mutex_unlock(&event->owner->perf_event_mutex);
2190 put_task_struct(event->owner);
2196 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
2199 * Called when the last reference to the file is gone.
2201 static int perf_release(struct inode *inode, struct file *file)
2203 struct perf_event *event = file->private_data;
2205 file->private_data = NULL;
2207 return perf_event_release_kernel(event);
2210 static int perf_event_read_size(struct perf_event *event)
2212 int entry = sizeof(u64); /* value */
2216 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2217 size += sizeof(u64);
2219 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2220 size += sizeof(u64);
2222 if (event->attr.read_format & PERF_FORMAT_ID)
2223 entry += sizeof(u64);
2225 if (event->attr.read_format & PERF_FORMAT_GROUP) {
2226 nr += event->group_leader->nr_siblings;
2227 size += sizeof(u64);
2235 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
2237 struct perf_event *child;
2243 mutex_lock(&event->child_mutex);
2244 total += perf_event_read(event);
2245 *enabled += event->total_time_enabled +
2246 atomic64_read(&event->child_total_time_enabled);
2247 *running += event->total_time_running +
2248 atomic64_read(&event->child_total_time_running);
2250 list_for_each_entry(child, &event->child_list, child_list) {
2251 total += perf_event_read(child);
2252 *enabled += child->total_time_enabled;
2253 *running += child->total_time_running;
2255 mutex_unlock(&event->child_mutex);
2259 EXPORT_SYMBOL_GPL(perf_event_read_value);
2261 static int perf_event_read_group(struct perf_event *event,
2262 u64 read_format, char __user *buf)
2264 struct perf_event *leader = event->group_leader, *sub;
2265 int n = 0, size = 0, ret = -EFAULT;
2266 struct perf_event_context *ctx = leader->ctx;
2268 u64 count, enabled, running;
2270 mutex_lock(&ctx->mutex);
2271 count = perf_event_read_value(leader, &enabled, &running);
2273 values[n++] = 1 + leader->nr_siblings;
2274 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2275 values[n++] = enabled;
2276 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2277 values[n++] = running;
2278 values[n++] = count;
2279 if (read_format & PERF_FORMAT_ID)
2280 values[n++] = primary_event_id(leader);
2282 size = n * sizeof(u64);
2284 if (copy_to_user(buf, values, size))
2289 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
2292 values[n++] = perf_event_read_value(sub, &enabled, &running);
2293 if (read_format & PERF_FORMAT_ID)
2294 values[n++] = primary_event_id(sub);
2296 size = n * sizeof(u64);
2298 if (copy_to_user(buf + ret, values, size)) {
2306 mutex_unlock(&ctx->mutex);
2311 static int perf_event_read_one(struct perf_event *event,
2312 u64 read_format, char __user *buf)
2314 u64 enabled, running;
2318 values[n++] = perf_event_read_value(event, &enabled, &running);
2319 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2320 values[n++] = enabled;
2321 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2322 values[n++] = running;
2323 if (read_format & PERF_FORMAT_ID)
2324 values[n++] = primary_event_id(event);
2326 if (copy_to_user(buf, values, n * sizeof(u64)))
2329 return n * sizeof(u64);
2333 * Read the performance event - simple non blocking version for now
2336 perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
2338 u64 read_format = event->attr.read_format;
2342 * Return end-of-file for a read on a event that is in
2343 * error state (i.e. because it was pinned but it couldn't be
2344 * scheduled on to the CPU at some point).
2346 if (event->state == PERF_EVENT_STATE_ERROR)
2349 if (count < perf_event_read_size(event))
2352 WARN_ON_ONCE(event->ctx->parent_ctx);
2353 if (read_format & PERF_FORMAT_GROUP)
2354 ret = perf_event_read_group(event, read_format, buf);
2356 ret = perf_event_read_one(event, read_format, buf);
2362 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
2364 struct perf_event *event = file->private_data;
2366 return perf_read_hw(event, buf, count);
2369 static unsigned int perf_poll(struct file *file, poll_table *wait)
2371 struct perf_event *event = file->private_data;
2372 struct perf_buffer *buffer;
2373 unsigned int events = POLL_HUP;
2376 buffer = rcu_dereference(event->buffer);
2378 events = atomic_xchg(&buffer->poll, 0);
2381 poll_wait(file, &event->waitq, wait);
2386 static void perf_event_reset(struct perf_event *event)
2388 (void)perf_event_read(event);
2389 local64_set(&event->count, 0);
2390 perf_event_update_userpage(event);
2394 * Holding the top-level event's child_mutex means that any
2395 * descendant process that has inherited this event will block
2396 * in sync_child_event if it goes to exit, thus satisfying the
2397 * task existence requirements of perf_event_enable/disable.
2399 static void perf_event_for_each_child(struct perf_event *event,
2400 void (*func)(struct perf_event *))
2402 struct perf_event *child;
2404 WARN_ON_ONCE(event->ctx->parent_ctx);
2405 mutex_lock(&event->child_mutex);
2407 list_for_each_entry(child, &event->child_list, child_list)
2409 mutex_unlock(&event->child_mutex);
2412 static void perf_event_for_each(struct perf_event *event,
2413 void (*func)(struct perf_event *))
2415 struct perf_event_context *ctx = event->ctx;
2416 struct perf_event *sibling;
2418 WARN_ON_ONCE(ctx->parent_ctx);
2419 mutex_lock(&ctx->mutex);
2420 event = event->group_leader;
2422 perf_event_for_each_child(event, func);
2424 list_for_each_entry(sibling, &event->sibling_list, group_entry)
2425 perf_event_for_each_child(event, func);
2426 mutex_unlock(&ctx->mutex);
2429 static int perf_event_period(struct perf_event *event, u64 __user *arg)
2431 struct perf_event_context *ctx = event->ctx;
2436 if (!event->attr.sample_period)
2439 size = copy_from_user(&value, arg, sizeof(value));
2440 if (size != sizeof(value))
2446 raw_spin_lock_irq(&ctx->lock);
2447 if (event->attr.freq) {
2448 if (value > sysctl_perf_event_sample_rate) {
2453 event->attr.sample_freq = value;
2455 event->attr.sample_period = value;
2456 event->hw.sample_period = value;
2459 raw_spin_unlock_irq(&ctx->lock);
2464 static const struct file_operations perf_fops;
2466 static struct perf_event *perf_fget_light(int fd, int *fput_needed)
2470 file = fget_light(fd, fput_needed);
2472 return ERR_PTR(-EBADF);
2474 if (file->f_op != &perf_fops) {
2475 fput_light(file, *fput_needed);
2477 return ERR_PTR(-EBADF);
2480 return file->private_data;
2483 static int perf_event_set_output(struct perf_event *event,
2484 struct perf_event *output_event);
2485 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
2487 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2489 struct perf_event *event = file->private_data;
2490 void (*func)(struct perf_event *);
2494 case PERF_EVENT_IOC_ENABLE:
2495 func = perf_event_enable;
2497 case PERF_EVENT_IOC_DISABLE:
2498 func = perf_event_disable;
2500 case PERF_EVENT_IOC_RESET:
2501 func = perf_event_reset;
2504 case PERF_EVENT_IOC_REFRESH:
2505 return perf_event_refresh(event, arg);
2507 case PERF_EVENT_IOC_PERIOD:
2508 return perf_event_period(event, (u64 __user *)arg);
2510 case PERF_EVENT_IOC_SET_OUTPUT:
2512 struct perf_event *output_event = NULL;
2513 int fput_needed = 0;
2517 output_event = perf_fget_light(arg, &fput_needed);
2518 if (IS_ERR(output_event))
2519 return PTR_ERR(output_event);
2522 ret = perf_event_set_output(event, output_event);
2524 fput_light(output_event->filp, fput_needed);
2529 case PERF_EVENT_IOC_SET_FILTER:
2530 return perf_event_set_filter(event, (void __user *)arg);
2536 if (flags & PERF_IOC_FLAG_GROUP)
2537 perf_event_for_each(event, func);
2539 perf_event_for_each_child(event, func);
2544 int perf_event_task_enable(void)
2546 struct perf_event *event;
2548 mutex_lock(¤t->perf_event_mutex);
2549 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
2550 perf_event_for_each_child(event, perf_event_enable);
2551 mutex_unlock(¤t->perf_event_mutex);
2556 int perf_event_task_disable(void)
2558 struct perf_event *event;
2560 mutex_lock(¤t->perf_event_mutex);
2561 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
2562 perf_event_for_each_child(event, perf_event_disable);
2563 mutex_unlock(¤t->perf_event_mutex);
2568 #ifndef PERF_EVENT_INDEX_OFFSET
2569 # define PERF_EVENT_INDEX_OFFSET 0
2572 static int perf_event_index(struct perf_event *event)
2574 if (event->hw.state & PERF_HES_STOPPED)
2577 if (event->state != PERF_EVENT_STATE_ACTIVE)
2580 return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
2584 * Callers need to ensure there can be no nesting of this function, otherwise
2585 * the seqlock logic goes bad. We can not serialize this because the arch
2586 * code calls this from NMI context.
2588 void perf_event_update_userpage(struct perf_event *event)
2590 struct perf_event_mmap_page *userpg;
2591 struct perf_buffer *buffer;
2594 buffer = rcu_dereference(event->buffer);
2598 userpg = buffer->user_page;
2601 * Disable preemption so as to not let the corresponding user-space
2602 * spin too long if we get preempted.
2607 userpg->index = perf_event_index(event);
2608 userpg->offset = perf_event_count(event);
2609 if (event->state == PERF_EVENT_STATE_ACTIVE)
2610 userpg->offset -= local64_read(&event->hw.prev_count);
2612 userpg->time_enabled = event->total_time_enabled +
2613 atomic64_read(&event->child_total_time_enabled);
2615 userpg->time_running = event->total_time_running +
2616 atomic64_read(&event->child_total_time_running);
2625 static unsigned long perf_data_size(struct perf_buffer *buffer);
2628 perf_buffer_init(struct perf_buffer *buffer, long watermark, int flags)
2630 long max_size = perf_data_size(buffer);
2633 buffer->watermark = min(max_size, watermark);
2635 if (!buffer->watermark)
2636 buffer->watermark = max_size / 2;
2638 if (flags & PERF_BUFFER_WRITABLE)
2639 buffer->writable = 1;
2641 atomic_set(&buffer->refcount, 1);
2644 #ifndef CONFIG_PERF_USE_VMALLOC
2647 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2650 static struct page *
2651 perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
2653 if (pgoff > buffer->nr_pages)
2657 return virt_to_page(buffer->user_page);
2659 return virt_to_page(buffer->data_pages[pgoff - 1]);
2662 static void *perf_mmap_alloc_page(int cpu)
2667 node = (cpu == -1) ? cpu : cpu_to_node(cpu);
2668 page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
2672 return page_address(page);
2675 static struct perf_buffer *
2676 perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
2678 struct perf_buffer *buffer;
2682 size = sizeof(struct perf_buffer);
2683 size += nr_pages * sizeof(void *);
2685 buffer = kzalloc(size, GFP_KERNEL);
2689 buffer->user_page = perf_mmap_alloc_page(cpu);
2690 if (!buffer->user_page)
2691 goto fail_user_page;
2693 for (i = 0; i < nr_pages; i++) {
2694 buffer->data_pages[i] = perf_mmap_alloc_page(cpu);
2695 if (!buffer->data_pages[i])
2696 goto fail_data_pages;
2699 buffer->nr_pages = nr_pages;
2701 perf_buffer_init(buffer, watermark, flags);
2706 for (i--; i >= 0; i--)
2707 free_page((unsigned long)buffer->data_pages[i]);
2709 free_page((unsigned long)buffer->user_page);
2718 static void perf_mmap_free_page(unsigned long addr)
2720 struct page *page = virt_to_page((void *)addr);
2722 page->mapping = NULL;
2726 static void perf_buffer_free(struct perf_buffer *buffer)
2730 perf_mmap_free_page((unsigned long)buffer->user_page);
2731 for (i = 0; i < buffer->nr_pages; i++)
2732 perf_mmap_free_page((unsigned long)buffer->data_pages[i]);
2736 static inline int page_order(struct perf_buffer *buffer)
2744 * Back perf_mmap() with vmalloc memory.
2746 * Required for architectures that have d-cache aliasing issues.
2749 static inline int page_order(struct perf_buffer *buffer)
2751 return buffer->page_order;
2754 static struct page *
2755 perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
2757 if (pgoff > (1UL << page_order(buffer)))
2760 return vmalloc_to_page((void *)buffer->user_page + pgoff * PAGE_SIZE);
2763 static void perf_mmap_unmark_page(void *addr)
2765 struct page *page = vmalloc_to_page(addr);
2767 page->mapping = NULL;
2770 static void perf_buffer_free_work(struct work_struct *work)
2772 struct perf_buffer *buffer;
2776 buffer = container_of(work, struct perf_buffer, work);
2777 nr = 1 << page_order(buffer);
2779 base = buffer->user_page;
2780 for (i = 0; i < nr + 1; i++)
2781 perf_mmap_unmark_page(base + (i * PAGE_SIZE));
2787 static void perf_buffer_free(struct perf_buffer *buffer)
2789 schedule_work(&buffer->work);
2792 static struct perf_buffer *
2793 perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
2795 struct perf_buffer *buffer;
2799 size = sizeof(struct perf_buffer);
2800 size += sizeof(void *);
2802 buffer = kzalloc(size, GFP_KERNEL);
2806 INIT_WORK(&buffer->work, perf_buffer_free_work);
2808 all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
2812 buffer->user_page = all_buf;
2813 buffer->data_pages[0] = all_buf + PAGE_SIZE;
2814 buffer->page_order = ilog2(nr_pages);
2815 buffer->nr_pages = 1;
2817 perf_buffer_init(buffer, watermark, flags);
2830 static unsigned long perf_data_size(struct perf_buffer *buffer)
2832 return buffer->nr_pages << (PAGE_SHIFT + page_order(buffer));
2835 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2837 struct perf_event *event = vma->vm_file->private_data;
2838 struct perf_buffer *buffer;
2839 int ret = VM_FAULT_SIGBUS;
2841 if (vmf->flags & FAULT_FLAG_MKWRITE) {
2842 if (vmf->pgoff == 0)
2848 buffer = rcu_dereference(event->buffer);
2852 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
2855 vmf->page = perf_mmap_to_page(buffer, vmf->pgoff);
2859 get_page(vmf->page);
2860 vmf->page->mapping = vma->vm_file->f_mapping;
2861 vmf->page->index = vmf->pgoff;
2870 static void perf_buffer_free_rcu(struct rcu_head *rcu_head)
2872 struct perf_buffer *buffer;
2874 buffer = container_of(rcu_head, struct perf_buffer, rcu_head);
2875 perf_buffer_free(buffer);
2878 static struct perf_buffer *perf_buffer_get(struct perf_event *event)
2880 struct perf_buffer *buffer;
2883 buffer = rcu_dereference(event->buffer);
2885 if (!atomic_inc_not_zero(&buffer->refcount))
2893 static void perf_buffer_put(struct perf_buffer *buffer)
2895 if (!atomic_dec_and_test(&buffer->refcount))
2898 call_rcu(&buffer->rcu_head, perf_buffer_free_rcu);
2901 static void perf_mmap_open(struct vm_area_struct *vma)
2903 struct perf_event *event = vma->vm_file->private_data;
2905 atomic_inc(&event->mmap_count);
2908 static void perf_mmap_close(struct vm_area_struct *vma)
2910 struct perf_event *event = vma->vm_file->private_data;
2912 if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
2913 unsigned long size = perf_data_size(event->buffer);
2914 struct user_struct *user = event->mmap_user;
2915 struct perf_buffer *buffer = event->buffer;
2917 atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
2918 vma->vm_mm->locked_vm -= event->mmap_locked;
2919 rcu_assign_pointer(event->buffer, NULL);
2920 mutex_unlock(&event->mmap_mutex);
2922 perf_buffer_put(buffer);
2927 static const struct vm_operations_struct perf_mmap_vmops = {
2928 .open = perf_mmap_open,
2929 .close = perf_mmap_close,
2930 .fault = perf_mmap_fault,
2931 .page_mkwrite = perf_mmap_fault,
2934 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
2936 struct perf_event *event = file->private_data;
2937 unsigned long user_locked, user_lock_limit;
2938 struct user_struct *user = current_user();
2939 unsigned long locked, lock_limit;
2940 struct perf_buffer *buffer;
2941 unsigned long vma_size;
2942 unsigned long nr_pages;
2943 long user_extra, extra;
2944 int ret = 0, flags = 0;
2947 * Don't allow mmap() of inherited per-task counters. This would
2948 * create a performance issue due to all children writing to the
2951 if (event->cpu == -1 && event->attr.inherit)
2954 if (!(vma->vm_flags & VM_SHARED))
2957 vma_size = vma->vm_end - vma->vm_start;
2958 nr_pages = (vma_size / PAGE_SIZE) - 1;
2961 * If we have buffer pages ensure they're a power-of-two number, so we
2962 * can do bitmasks instead of modulo.
2964 if (nr_pages != 0 && !is_power_of_2(nr_pages))
2967 if (vma_size != PAGE_SIZE * (1 + nr_pages))
2970 if (vma->vm_pgoff != 0)
2973 WARN_ON_ONCE(event->ctx->parent_ctx);
2974 mutex_lock(&event->mmap_mutex);
2975 if (event->buffer) {
2976 if (event->buffer->nr_pages == nr_pages)
2977 atomic_inc(&event->buffer->refcount);
2983 user_extra = nr_pages + 1;
2984 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
2987 * Increase the limit linearly with more CPUs:
2989 user_lock_limit *= num_online_cpus();
2991 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
2994 if (user_locked > user_lock_limit)
2995 extra = user_locked - user_lock_limit;
2997 lock_limit = rlimit(RLIMIT_MEMLOCK);
2998 lock_limit >>= PAGE_SHIFT;
2999 locked = vma->vm_mm->locked_vm + extra;
3001 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
3002 !capable(CAP_IPC_LOCK)) {
3007 WARN_ON(event->buffer);
3009 if (vma->vm_flags & VM_WRITE)
3010 flags |= PERF_BUFFER_WRITABLE;
3012 buffer = perf_buffer_alloc(nr_pages, event->attr.wakeup_watermark,
3018 rcu_assign_pointer(event->buffer, buffer);
3020 atomic_long_add(user_extra, &user->locked_vm);
3021 event->mmap_locked = extra;
3022 event->mmap_user = get_current_user();
3023 vma->vm_mm->locked_vm += event->mmap_locked;
3027 atomic_inc(&event->mmap_count);
3028 mutex_unlock(&event->mmap_mutex);
3030 vma->vm_flags |= VM_RESERVED;
3031 vma->vm_ops = &perf_mmap_vmops;
3036 static int perf_fasync(int fd, struct file *filp, int on)
3038 struct inode *inode = filp->f_path.dentry->d_inode;
3039 struct perf_event *event = filp->private_data;
3042 mutex_lock(&inode->i_mutex);
3043 retval = fasync_helper(fd, filp, on, &event->fasync);
3044 mutex_unlock(&inode->i_mutex);
3052 static const struct file_operations perf_fops = {
3053 .llseek = no_llseek,
3054 .release = perf_release,
3057 .unlocked_ioctl = perf_ioctl,
3058 .compat_ioctl = perf_ioctl,
3060 .fasync = perf_fasync,
3066 * If there's data, ensure we set the poll() state and publish everything
3067 * to user-space before waking everybody up.
3070 void perf_event_wakeup(struct perf_event *event)
3072 wake_up_all(&event->waitq);
3074 if (event->pending_kill) {
3075 kill_fasync(&event->fasync, SIGIO, event->pending_kill);
3076 event->pending_kill = 0;
3083 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
3085 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
3086 * single linked list and use cmpxchg() to add entries lockless.
3089 static void perf_pending_event(struct perf_pending_entry *entry)
3091 struct perf_event *event = container_of(entry,
3092 struct perf_event, pending);
3094 if (event->pending_disable) {
3095 event->pending_disable = 0;
3096 __perf_event_disable(event);
3099 if (event->pending_wakeup) {
3100 event->pending_wakeup = 0;
3101 perf_event_wakeup(event);
3105 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
3107 static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
3111 static void perf_pending_queue(struct perf_pending_entry *entry,
3112 void (*func)(struct perf_pending_entry *))
3114 struct perf_pending_entry **head;
3116 if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
3121 head = &get_cpu_var(perf_pending_head);
3124 entry->next = *head;
3125 } while (cmpxchg(head, entry->next, entry) != entry->next);
3127 set_perf_event_pending();
3129 put_cpu_var(perf_pending_head);
3132 static int __perf_pending_run(void)
3134 struct perf_pending_entry *list;
3137 list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
3138 while (list != PENDING_TAIL) {
3139 void (*func)(struct perf_pending_entry *);
3140 struct perf_pending_entry *entry = list;
3147 * Ensure we observe the unqueue before we issue the wakeup,
3148 * so that we won't be waiting forever.
3149 * -- see perf_not_pending().
3160 static inline int perf_not_pending(struct perf_event *event)
3163 * If we flush on whatever cpu we run, there is a chance we don't
3167 __perf_pending_run();
3171 * Ensure we see the proper queue state before going to sleep
3172 * so that we do not miss the wakeup. -- see perf_pending_handle()
3175 return event->pending.next == NULL;
3178 static void perf_pending_sync(struct perf_event *event)
3180 wait_event(event->waitq, perf_not_pending(event));
3183 void perf_event_do_pending(void)
3185 __perf_pending_run();
3189 * We assume there is only KVM supporting the callbacks.
3190 * Later on, we might change it to a list if there is
3191 * another virtualization implementation supporting the callbacks.
3193 struct perf_guest_info_callbacks *perf_guest_cbs;
3195 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
3197 perf_guest_cbs = cbs;
3200 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
3202 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
3204 perf_guest_cbs = NULL;
3207 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
3212 static bool perf_output_space(struct perf_buffer *buffer, unsigned long tail,
3213 unsigned long offset, unsigned long head)
3217 if (!buffer->writable)
3220 mask = perf_data_size(buffer) - 1;
3222 offset = (offset - tail) & mask;
3223 head = (head - tail) & mask;
3225 if ((int)(head - offset) < 0)
3231 static void perf_output_wakeup(struct perf_output_handle *handle)
3233 atomic_set(&handle->buffer->poll, POLL_IN);
3236 handle->event->pending_wakeup = 1;
3237 perf_pending_queue(&handle->event->pending,
3238 perf_pending_event);
3240 perf_event_wakeup(handle->event);
3244 * We need to ensure a later event_id doesn't publish a head when a former
3245 * event isn't done writing. However since we need to deal with NMIs we
3246 * cannot fully serialize things.
3248 * We only publish the head (and generate a wakeup) when the outer-most
3251 static void perf_output_get_handle(struct perf_output_handle *handle)
3253 struct perf_buffer *buffer = handle->buffer;
3256 local_inc(&buffer->nest);
3257 handle->wakeup = local_read(&buffer->wakeup);
3260 static void perf_output_put_handle(struct perf_output_handle *handle)
3262 struct perf_buffer *buffer = handle->buffer;
3266 head = local_read(&buffer->head);
3269 * IRQ/NMI can happen here, which means we can miss a head update.
3272 if (!local_dec_and_test(&buffer->nest))
3276 * Publish the known good head. Rely on the full barrier implied
3277 * by atomic_dec_and_test() order the buffer->head read and this
3280 buffer->user_page->data_head = head;
3283 * Now check if we missed an update, rely on the (compiler)
3284 * barrier in atomic_dec_and_test() to re-read buffer->head.
3286 if (unlikely(head != local_read(&buffer->head))) {
3287 local_inc(&buffer->nest);
3291 if (handle->wakeup != local_read(&buffer->wakeup))
3292 perf_output_wakeup(handle);
3298 __always_inline void perf_output_copy(struct perf_output_handle *handle,
3299 const void *buf, unsigned int len)
3302 unsigned long size = min_t(unsigned long, handle->size, len);
3304 memcpy(handle->addr, buf, size);
3307 handle->addr += size;
3309 handle->size -= size;
3310 if (!handle->size) {
3311 struct perf_buffer *buffer = handle->buffer;
3314 handle->page &= buffer->nr_pages - 1;
3315 handle->addr = buffer->data_pages[handle->page];
3316 handle->size = PAGE_SIZE << page_order(buffer);
3321 int perf_output_begin(struct perf_output_handle *handle,
3322 struct perf_event *event, unsigned int size,
3323 int nmi, int sample)
3325 struct perf_buffer *buffer;
3326 unsigned long tail, offset, head;
3329 struct perf_event_header header;
3336 * For inherited events we send all the output towards the parent.
3339 event = event->parent;
3341 buffer = rcu_dereference(event->buffer);
3345 handle->buffer = buffer;
3346 handle->event = event;
3348 handle->sample = sample;
3350 if (!buffer->nr_pages)
3353 have_lost = local_read(&buffer->lost);
3355 size += sizeof(lost_event);
3357 perf_output_get_handle(handle);
3361 * Userspace could choose to issue a mb() before updating the
3362 * tail pointer. So that all reads will be completed before the
3365 tail = ACCESS_ONCE(buffer->user_page->data_tail);
3367 offset = head = local_read(&buffer->head);
3369 if (unlikely(!perf_output_space(buffer, tail, offset, head)))
3371 } while (local_cmpxchg(&buffer->head, offset, head) != offset);
3373 if (head - local_read(&buffer->wakeup) > buffer->watermark)
3374 local_add(buffer->watermark, &buffer->wakeup);
3376 handle->page = offset >> (PAGE_SHIFT + page_order(buffer));
3377 handle->page &= buffer->nr_pages - 1;
3378 handle->size = offset & ((PAGE_SIZE << page_order(buffer)) - 1);
3379 handle->addr = buffer->data_pages[handle->page];
3380 handle->addr += handle->size;
3381 handle->size = (PAGE_SIZE << page_order(buffer)) - handle->size;
3384 lost_event.header.type = PERF_RECORD_LOST;
3385 lost_event.header.misc = 0;
3386 lost_event.header.size = sizeof(lost_event);
3387 lost_event.id = event->id;
3388 lost_event.lost = local_xchg(&buffer->lost, 0);
3390 perf_output_put(handle, lost_event);
3396 local_inc(&buffer->lost);
3397 perf_output_put_handle(handle);
3404 void perf_output_end(struct perf_output_handle *handle)
3406 struct perf_event *event = handle->event;
3407 struct perf_buffer *buffer = handle->buffer;
3409 int wakeup_events = event->attr.wakeup_events;
3411 if (handle->sample && wakeup_events) {
3412 int events = local_inc_return(&buffer->events);
3413 if (events >= wakeup_events) {
3414 local_sub(wakeup_events, &buffer->events);
3415 local_inc(&buffer->wakeup);
3419 perf_output_put_handle(handle);
3423 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
3426 * only top level events have the pid namespace they were created in
3429 event = event->parent;
3431 return task_tgid_nr_ns(p, event->ns);
3434 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
3437 * only top level events have the pid namespace they were created in
3440 event = event->parent;
3442 return task_pid_nr_ns(p, event->ns);
3445 static void perf_output_read_one(struct perf_output_handle *handle,
3446 struct perf_event *event)
3448 u64 read_format = event->attr.read_format;
3452 values[n++] = perf_event_count(event);
3453 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3454 values[n++] = event->total_time_enabled +
3455 atomic64_read(&event->child_total_time_enabled);
3457 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3458 values[n++] = event->total_time_running +
3459 atomic64_read(&event->child_total_time_running);
3461 if (read_format & PERF_FORMAT_ID)
3462 values[n++] = primary_event_id(event);
3464 perf_output_copy(handle, values, n * sizeof(u64));
3468 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3470 static void perf_output_read_group(struct perf_output_handle *handle,
3471 struct perf_event *event)
3473 struct perf_event *leader = event->group_leader, *sub;
3474 u64 read_format = event->attr.read_format;
3478 values[n++] = 1 + leader->nr_siblings;
3480 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3481 values[n++] = leader->total_time_enabled;
3483 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3484 values[n++] = leader->total_time_running;
3486 if (leader != event)
3487 leader->pmu->read(leader);
3489 values[n++] = perf_event_count(leader);
3490 if (read_format & PERF_FORMAT_ID)
3491 values[n++] = primary_event_id(leader);
3493 perf_output_copy(handle, values, n * sizeof(u64));
3495 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3499 sub->pmu->read(sub);
3501 values[n++] = perf_event_count(sub);
3502 if (read_format & PERF_FORMAT_ID)
3503 values[n++] = primary_event_id(sub);
3505 perf_output_copy(handle, values, n * sizeof(u64));
3509 static void perf_output_read(struct perf_output_handle *handle,
3510 struct perf_event *event)
3512 if (event->attr.read_format & PERF_FORMAT_GROUP)
3513 perf_output_read_group(handle, event);
3515 perf_output_read_one(handle, event);
3518 void perf_output_sample(struct perf_output_handle *handle,
3519 struct perf_event_header *header,
3520 struct perf_sample_data *data,
3521 struct perf_event *event)
3523 u64 sample_type = data->type;
3525 perf_output_put(handle, *header);
3527 if (sample_type & PERF_SAMPLE_IP)
3528 perf_output_put(handle, data->ip);
3530 if (sample_type & PERF_SAMPLE_TID)
3531 perf_output_put(handle, data->tid_entry);
3533 if (sample_type & PERF_SAMPLE_TIME)
3534 perf_output_put(handle, data->time);
3536 if (sample_type & PERF_SAMPLE_ADDR)
3537 perf_output_put(handle, data->addr);
3539 if (sample_type & PERF_SAMPLE_ID)
3540 perf_output_put(handle, data->id);
3542 if (sample_type & PERF_SAMPLE_STREAM_ID)
3543 perf_output_put(handle, data->stream_id);
3545 if (sample_type & PERF_SAMPLE_CPU)
3546 perf_output_put(handle, data->cpu_entry);
3548 if (sample_type & PERF_SAMPLE_PERIOD)
3549 perf_output_put(handle, data->period);
3551 if (sample_type & PERF_SAMPLE_READ)
3552 perf_output_read(handle, event);
3554 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3555 if (data->callchain) {
3558 if (data->callchain)
3559 size += data->callchain->nr;
3561 size *= sizeof(u64);
3563 perf_output_copy(handle, data->callchain, size);
3566 perf_output_put(handle, nr);
3570 if (sample_type & PERF_SAMPLE_RAW) {
3572 perf_output_put(handle, data->raw->size);
3573 perf_output_copy(handle, data->raw->data,
3580 .size = sizeof(u32),
3583 perf_output_put(handle, raw);
3588 void perf_prepare_sample(struct perf_event_header *header,
3589 struct perf_sample_data *data,
3590 struct perf_event *event,
3591 struct pt_regs *regs)
3593 u64 sample_type = event->attr.sample_type;
3595 data->type = sample_type;
3597 header->type = PERF_RECORD_SAMPLE;
3598 header->size = sizeof(*header);
3601 header->misc |= perf_misc_flags(regs);
3603 if (sample_type & PERF_SAMPLE_IP) {
3604 data->ip = perf_instruction_pointer(regs);
3606 header->size += sizeof(data->ip);
3609 if (sample_type & PERF_SAMPLE_TID) {
3610 /* namespace issues */
3611 data->tid_entry.pid = perf_event_pid(event, current);
3612 data->tid_entry.tid = perf_event_tid(event, current);
3614 header->size += sizeof(data->tid_entry);
3617 if (sample_type & PERF_SAMPLE_TIME) {
3618 data->time = perf_clock();
3620 header->size += sizeof(data->time);
3623 if (sample_type & PERF_SAMPLE_ADDR)
3624 header->size += sizeof(data->addr);
3626 if (sample_type & PERF_SAMPLE_ID) {
3627 data->id = primary_event_id(event);
3629 header->size += sizeof(data->id);
3632 if (sample_type & PERF_SAMPLE_STREAM_ID) {
3633 data->stream_id = event->id;
3635 header->size += sizeof(data->stream_id);
3638 if (sample_type & PERF_SAMPLE_CPU) {
3639 data->cpu_entry.cpu = raw_smp_processor_id();
3640 data->cpu_entry.reserved = 0;
3642 header->size += sizeof(data->cpu_entry);
3645 if (sample_type & PERF_SAMPLE_PERIOD)
3646 header->size += sizeof(data->period);
3648 if (sample_type & PERF_SAMPLE_READ)
3649 header->size += perf_event_read_size(event);
3651 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3654 data->callchain = perf_callchain(regs);
3656 if (data->callchain)
3657 size += data->callchain->nr;
3659 header->size += size * sizeof(u64);
3662 if (sample_type & PERF_SAMPLE_RAW) {
3663 int size = sizeof(u32);
3666 size += data->raw->size;
3668 size += sizeof(u32);
3670 WARN_ON_ONCE(size & (sizeof(u64)-1));
3671 header->size += size;
3675 static void perf_event_output(struct perf_event *event, int nmi,
3676 struct perf_sample_data *data,
3677 struct pt_regs *regs)
3679 struct perf_output_handle handle;
3680 struct perf_event_header header;
3682 /* protect the callchain buffers */
3685 perf_prepare_sample(&header, data, event, regs);
3687 if (perf_output_begin(&handle, event, header.size, nmi, 1))
3690 perf_output_sample(&handle, &header, data, event);
3692 perf_output_end(&handle);
3702 struct perf_read_event {
3703 struct perf_event_header header;
3710 perf_event_read_event(struct perf_event *event,
3711 struct task_struct *task)
3713 struct perf_output_handle handle;
3714 struct perf_read_event read_event = {
3716 .type = PERF_RECORD_READ,
3718 .size = sizeof(read_event) + perf_event_read_size(event),
3720 .pid = perf_event_pid(event, task),
3721 .tid = perf_event_tid(event, task),
3725 ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
3729 perf_output_put(&handle, read_event);
3730 perf_output_read(&handle, event);
3732 perf_output_end(&handle);
3736 * task tracking -- fork/exit
3738 * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
3741 struct perf_task_event {
3742 struct task_struct *task;
3743 struct perf_event_context *task_ctx;
3746 struct perf_event_header header;
3756 static void perf_event_task_output(struct perf_event *event,
3757 struct perf_task_event *task_event)
3759 struct perf_output_handle handle;
3760 struct task_struct *task = task_event->task;
3763 size = task_event->event_id.header.size;
3764 ret = perf_output_begin(&handle, event, size, 0, 0);
3769 task_event->event_id.pid = perf_event_pid(event, task);
3770 task_event->event_id.ppid = perf_event_pid(event, current);
3772 task_event->event_id.tid = perf_event_tid(event, task);
3773 task_event->event_id.ptid = perf_event_tid(event, current);
3775 perf_output_put(&handle, task_event->event_id);
3777 perf_output_end(&handle);
3780 static int perf_event_task_match(struct perf_event *event)
3782 if (event->state < PERF_EVENT_STATE_INACTIVE)
3785 if (event->cpu != -1 && event->cpu != smp_processor_id())
3788 if (event->attr.comm || event->attr.mmap ||
3789 event->attr.mmap_data || event->attr.task)
3795 static void perf_event_task_ctx(struct perf_event_context *ctx,
3796 struct perf_task_event *task_event)
3798 struct perf_event *event;
3800 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3801 if (perf_event_task_match(event))
3802 perf_event_task_output(event, task_event);
3806 static void perf_event_task_event(struct perf_task_event *task_event)
3808 struct perf_cpu_context *cpuctx;
3809 struct perf_event_context *ctx;
3813 rcu_read_lock_sched();
3814 list_for_each_entry_rcu(pmu, &pmus, entry) {
3815 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3816 perf_event_task_ctx(&cpuctx->ctx, task_event);
3818 ctx = task_event->task_ctx;
3820 ctxn = pmu->task_ctx_nr;
3823 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
3826 perf_event_task_ctx(ctx, task_event);
3828 rcu_read_unlock_sched();
3831 static void perf_event_task(struct task_struct *task,
3832 struct perf_event_context *task_ctx,
3835 struct perf_task_event task_event;
3837 if (!atomic_read(&nr_comm_events) &&
3838 !atomic_read(&nr_mmap_events) &&
3839 !atomic_read(&nr_task_events))
3842 task_event = (struct perf_task_event){
3844 .task_ctx = task_ctx,
3847 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
3849 .size = sizeof(task_event.event_id),
3855 .time = perf_clock(),
3859 perf_event_task_event(&task_event);
3862 void perf_event_fork(struct task_struct *task)
3864 perf_event_task(task, NULL, 1);
3871 struct perf_comm_event {
3872 struct task_struct *task;
3877 struct perf_event_header header;
3884 static void perf_event_comm_output(struct perf_event *event,
3885 struct perf_comm_event *comm_event)
3887 struct perf_output_handle handle;
3888 int size = comm_event->event_id.header.size;
3889 int ret = perf_output_begin(&handle, event, size, 0, 0);
3894 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
3895 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
3897 perf_output_put(&handle, comm_event->event_id);
3898 perf_output_copy(&handle, comm_event->comm,
3899 comm_event->comm_size);
3900 perf_output_end(&handle);
3903 static int perf_event_comm_match(struct perf_event *event)
3905 if (event->state < PERF_EVENT_STATE_INACTIVE)
3908 if (event->cpu != -1 && event->cpu != smp_processor_id())
3911 if (event->attr.comm)
3917 static void perf_event_comm_ctx(struct perf_event_context *ctx,
3918 struct perf_comm_event *comm_event)
3920 struct perf_event *event;
3922 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3923 if (perf_event_comm_match(event))
3924 perf_event_comm_output(event, comm_event);
3928 static void perf_event_comm_event(struct perf_comm_event *comm_event)
3930 struct perf_cpu_context *cpuctx;
3931 struct perf_event_context *ctx;
3932 char comm[TASK_COMM_LEN];
3937 memset(comm, 0, sizeof(comm));
3938 strlcpy(comm, comm_event->task->comm, sizeof(comm));
3939 size = ALIGN(strlen(comm)+1, sizeof(u64));
3941 comm_event->comm = comm;
3942 comm_event->comm_size = size;
3944 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
3946 rcu_read_lock_sched();
3947 list_for_each_entry_rcu(pmu, &pmus, entry) {
3948 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3949 perf_event_comm_ctx(&cpuctx->ctx, comm_event);
3951 ctxn = pmu->task_ctx_nr;
3955 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
3957 perf_event_comm_ctx(ctx, comm_event);
3959 rcu_read_unlock_sched();
3962 void perf_event_comm(struct task_struct *task)
3964 struct perf_comm_event comm_event;
3965 struct perf_event_context *ctx;
3968 for_each_task_context_nr(ctxn) {
3969 ctx = task->perf_event_ctxp[ctxn];
3973 perf_event_enable_on_exec(ctx);
3976 if (!atomic_read(&nr_comm_events))
3979 comm_event = (struct perf_comm_event){
3985 .type = PERF_RECORD_COMM,
3994 perf_event_comm_event(&comm_event);
4001 struct perf_mmap_event {
4002 struct vm_area_struct *vma;
4004 const char *file_name;
4008 struct perf_event_header header;
4018 static void perf_event_mmap_output(struct perf_event *event,
4019 struct perf_mmap_event *mmap_event)
4021 struct perf_output_handle handle;
4022 int size = mmap_event->event_id.header.size;
4023 int ret = perf_output_begin(&handle, event, size, 0, 0);
4028 mmap_event->event_id.pid = perf_event_pid(event, current);
4029 mmap_event->event_id.tid = perf_event_tid(event, current);
4031 perf_output_put(&handle, mmap_event->event_id);
4032 perf_output_copy(&handle, mmap_event->file_name,
4033 mmap_event->file_size);
4034 perf_output_end(&handle);
4037 static int perf_event_mmap_match(struct perf_event *event,
4038 struct perf_mmap_event *mmap_event,
4041 if (event->state < PERF_EVENT_STATE_INACTIVE)
4044 if (event->cpu != -1 && event->cpu != smp_processor_id())
4047 if ((!executable && event->attr.mmap_data) ||
4048 (executable && event->attr.mmap))
4054 static void perf_event_mmap_ctx(struct perf_event_context *ctx,
4055 struct perf_mmap_event *mmap_event,
4058 struct perf_event *event;
4060 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4061 if (perf_event_mmap_match(event, mmap_event, executable))
4062 perf_event_mmap_output(event, mmap_event);
4066 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
4068 struct perf_cpu_context *cpuctx;
4069 struct perf_event_context *ctx;
4070 struct vm_area_struct *vma = mmap_event->vma;
4071 struct file *file = vma->vm_file;
4079 memset(tmp, 0, sizeof(tmp));
4083 * d_path works from the end of the buffer backwards, so we
4084 * need to add enough zero bytes after the string to handle
4085 * the 64bit alignment we do later.
4087 buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
4089 name = strncpy(tmp, "//enomem", sizeof(tmp));
4092 name = d_path(&file->f_path, buf, PATH_MAX);
4094 name = strncpy(tmp, "//toolong", sizeof(tmp));
4098 if (arch_vma_name(mmap_event->vma)) {
4099 name = strncpy(tmp, arch_vma_name(mmap_event->vma),
4105 name = strncpy(tmp, "[vdso]", sizeof(tmp));
4107 } else if (vma->vm_start <= vma->vm_mm->start_brk &&
4108 vma->vm_end >= vma->vm_mm->brk) {
4109 name = strncpy(tmp, "[heap]", sizeof(tmp));
4111 } else if (vma->vm_start <= vma->vm_mm->start_stack &&
4112 vma->vm_end >= vma->vm_mm->start_stack) {
4113 name = strncpy(tmp, "[stack]", sizeof(tmp));
4117 name = strncpy(tmp, "//anon", sizeof(tmp));
4122 size = ALIGN(strlen(name)+1, sizeof(u64));
4124 mmap_event->file_name = name;
4125 mmap_event->file_size = size;
4127 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
4129 rcu_read_lock_sched();
4130 list_for_each_entry_rcu(pmu, &pmus, entry) {
4131 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
4132 perf_event_mmap_ctx(&cpuctx->ctx, mmap_event,
4133 vma->vm_flags & VM_EXEC);
4135 ctxn = pmu->task_ctx_nr;
4139 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4141 perf_event_mmap_ctx(ctx, mmap_event,
4142 vma->vm_flags & VM_EXEC);
4145 rcu_read_unlock_sched();
4150 void perf_event_mmap(struct vm_area_struct *vma)
4152 struct perf_mmap_event mmap_event;
4154 if (!atomic_read(&nr_mmap_events))
4157 mmap_event = (struct perf_mmap_event){
4163 .type = PERF_RECORD_MMAP,
4164 .misc = PERF_RECORD_MISC_USER,
4169 .start = vma->vm_start,
4170 .len = vma->vm_end - vma->vm_start,
4171 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
4175 perf_event_mmap_event(&mmap_event);
4179 * IRQ throttle logging
4182 static void perf_log_throttle(struct perf_event *event, int enable)
4184 struct perf_output_handle handle;
4188 struct perf_event_header header;
4192 } throttle_event = {
4194 .type = PERF_RECORD_THROTTLE,
4196 .size = sizeof(throttle_event),
4198 .time = perf_clock(),
4199 .id = primary_event_id(event),
4200 .stream_id = event->id,
4204 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
4206 ret = perf_output_begin(&handle, event, sizeof(throttle_event), 1, 0);
4210 perf_output_put(&handle, throttle_event);
4211 perf_output_end(&handle);
4215 * Generic event overflow handling, sampling.
4218 static int __perf_event_overflow(struct perf_event *event, int nmi,
4219 int throttle, struct perf_sample_data *data,
4220 struct pt_regs *regs)
4222 int events = atomic_read(&event->event_limit);
4223 struct hw_perf_event *hwc = &event->hw;
4229 if (hwc->interrupts != MAX_INTERRUPTS) {
4231 if (HZ * hwc->interrupts >
4232 (u64)sysctl_perf_event_sample_rate) {
4233 hwc->interrupts = MAX_INTERRUPTS;
4234 perf_log_throttle(event, 0);
4239 * Keep re-disabling events even though on the previous
4240 * pass we disabled it - just in case we raced with a
4241 * sched-in and the event got enabled again:
4247 if (event->attr.freq) {
4248 u64 now = perf_clock();
4249 s64 delta = now - hwc->freq_time_stamp;
4251 hwc->freq_time_stamp = now;
4253 if (delta > 0 && delta < 2*TICK_NSEC)
4254 perf_adjust_period(event, delta, hwc->last_period);
4258 * XXX event_limit might not quite work as expected on inherited
4262 event->pending_kill = POLL_IN;
4263 if (events && atomic_dec_and_test(&event->event_limit)) {
4265 event->pending_kill = POLL_HUP;
4267 event->pending_disable = 1;
4268 perf_pending_queue(&event->pending,
4269 perf_pending_event);
4271 perf_event_disable(event);
4274 if (event->overflow_handler)
4275 event->overflow_handler(event, nmi, data, regs);
4277 perf_event_output(event, nmi, data, regs);
4282 int perf_event_overflow(struct perf_event *event, int nmi,
4283 struct perf_sample_data *data,
4284 struct pt_regs *regs)
4286 return __perf_event_overflow(event, nmi, 1, data, regs);
4290 * Generic software event infrastructure
4293 struct swevent_htable {
4294 struct swevent_hlist *swevent_hlist;
4295 struct mutex hlist_mutex;
4298 /* Recursion avoidance in each contexts */
4299 int recursion[PERF_NR_CONTEXTS];
4302 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
4305 * We directly increment event->count and keep a second value in
4306 * event->hw.period_left to count intervals. This period event
4307 * is kept in the range [-sample_period, 0] so that we can use the
4311 static u64 perf_swevent_set_period(struct perf_event *event)
4313 struct hw_perf_event *hwc = &event->hw;
4314 u64 period = hwc->last_period;
4318 hwc->last_period = hwc->sample_period;
4321 old = val = local64_read(&hwc->period_left);
4325 nr = div64_u64(period + val, period);
4326 offset = nr * period;
4328 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
4334 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
4335 int nmi, struct perf_sample_data *data,
4336 struct pt_regs *regs)
4338 struct hw_perf_event *hwc = &event->hw;
4341 data->period = event->hw.last_period;
4343 overflow = perf_swevent_set_period(event);
4345 if (hwc->interrupts == MAX_INTERRUPTS)
4348 for (; overflow; overflow--) {
4349 if (__perf_event_overflow(event, nmi, throttle,
4352 * We inhibit the overflow from happening when
4353 * hwc->interrupts == MAX_INTERRUPTS.
4361 static void perf_swevent_event(struct perf_event *event, u64 nr,
4362 int nmi, struct perf_sample_data *data,
4363 struct pt_regs *regs)
4365 struct hw_perf_event *hwc = &event->hw;
4367 local64_add(nr, &event->count);
4372 if (!hwc->sample_period)
4375 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
4376 return perf_swevent_overflow(event, 1, nmi, data, regs);
4378 if (local64_add_negative(nr, &hwc->period_left))
4381 perf_swevent_overflow(event, 0, nmi, data, regs);
4384 static int perf_exclude_event(struct perf_event *event,
4385 struct pt_regs *regs)
4387 if (event->hw.state & PERF_HES_STOPPED)
4391 if (event->attr.exclude_user && user_mode(regs))
4394 if (event->attr.exclude_kernel && !user_mode(regs))
4401 static int perf_swevent_match(struct perf_event *event,
4402 enum perf_type_id type,
4404 struct perf_sample_data *data,
4405 struct pt_regs *regs)
4407 if (event->attr.type != type)
4410 if (event->attr.config != event_id)
4413 if (perf_exclude_event(event, regs))
4419 static inline u64 swevent_hash(u64 type, u32 event_id)
4421 u64 val = event_id | (type << 32);
4423 return hash_64(val, SWEVENT_HLIST_BITS);
4426 static inline struct hlist_head *
4427 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
4429 u64 hash = swevent_hash(type, event_id);
4431 return &hlist->heads[hash];
4434 /* For the read side: events when they trigger */
4435 static inline struct hlist_head *
4436 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
4438 struct swevent_hlist *hlist;
4440 hlist = rcu_dereference(swhash->swevent_hlist);
4444 return __find_swevent_head(hlist, type, event_id);
4447 /* For the event head insertion and removal in the hlist */
4448 static inline struct hlist_head *
4449 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
4451 struct swevent_hlist *hlist;
4452 u32 event_id = event->attr.config;
4453 u64 type = event->attr.type;
4456 * Event scheduling is always serialized against hlist allocation
4457 * and release. Which makes the protected version suitable here.
4458 * The context lock guarantees that.
4460 hlist = rcu_dereference_protected(swhash->swevent_hlist,
4461 lockdep_is_held(&event->ctx->lock));
4465 return __find_swevent_head(hlist, type, event_id);
4468 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
4470 struct perf_sample_data *data,
4471 struct pt_regs *regs)
4473 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
4474 struct perf_event *event;
4475 struct hlist_node *node;
4476 struct hlist_head *head;
4479 head = find_swevent_head_rcu(swhash, type, event_id);
4483 hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
4484 if (perf_swevent_match(event, type, event_id, data, regs))
4485 perf_swevent_event(event, nr, nmi, data, regs);
4491 int perf_swevent_get_recursion_context(void)
4493 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
4495 return get_recursion_context(swhash->recursion);
4497 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
4499 void inline perf_swevent_put_recursion_context(int rctx)
4501 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
4503 put_recursion_context(swhash->recursion, rctx);
4506 void __perf_sw_event(u32 event_id, u64 nr, int nmi,
4507 struct pt_regs *regs, u64 addr)
4509 struct perf_sample_data data;
4512 preempt_disable_notrace();
4513 rctx = perf_swevent_get_recursion_context();
4517 perf_sample_data_init(&data, addr);
4519 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
4521 perf_swevent_put_recursion_context(rctx);
4522 preempt_enable_notrace();
4525 static void perf_swevent_read(struct perf_event *event)
4529 static int perf_swevent_add(struct perf_event *event, int flags)
4531 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
4532 struct hw_perf_event *hwc = &event->hw;
4533 struct hlist_head *head;
4535 if (hwc->sample_period) {
4536 hwc->last_period = hwc->sample_period;
4537 perf_swevent_set_period(event);
4540 hwc->state = !(flags & PERF_EF_START);
4542 head = find_swevent_head(swhash, event);
4543 if (WARN_ON_ONCE(!head))
4546 hlist_add_head_rcu(&event->hlist_entry, head);
4551 static void perf_swevent_del(struct perf_event *event, int flags)
4553 hlist_del_rcu(&event->hlist_entry);
4556 static void perf_swevent_start(struct perf_event *event, int flags)
4558 event->hw.state = 0;
4561 static void perf_swevent_stop(struct perf_event *event, int flags)
4563 event->hw.state = PERF_HES_STOPPED;
4566 /* Deref the hlist from the update side */
4567 static inline struct swevent_hlist *
4568 swevent_hlist_deref(struct swevent_htable *swhash)
4570 return rcu_dereference_protected(swhash->swevent_hlist,
4571 lockdep_is_held(&swhash->hlist_mutex));
4574 static void swevent_hlist_release_rcu(struct rcu_head *rcu_head)
4576 struct swevent_hlist *hlist;
4578 hlist = container_of(rcu_head, struct swevent_hlist, rcu_head);
4582 static void swevent_hlist_release(struct swevent_htable *swhash)
4584 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
4589 rcu_assign_pointer(swhash->swevent_hlist, NULL);
4590 call_rcu(&hlist->rcu_head, swevent_hlist_release_rcu);
4593 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
4595 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
4597 mutex_lock(&swhash->hlist_mutex);
4599 if (!--swhash->hlist_refcount)
4600 swevent_hlist_release(swhash);
4602 mutex_unlock(&swhash->hlist_mutex);
4605 static void swevent_hlist_put(struct perf_event *event)
4609 if (event->cpu != -1) {
4610 swevent_hlist_put_cpu(event, event->cpu);
4614 for_each_possible_cpu(cpu)
4615 swevent_hlist_put_cpu(event, cpu);
4618 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
4620 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
4623 mutex_lock(&swhash->hlist_mutex);
4625 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
4626 struct swevent_hlist *hlist;
4628 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
4633 rcu_assign_pointer(swhash->swevent_hlist, hlist);
4635 swhash->hlist_refcount++;
4637 mutex_unlock(&swhash->hlist_mutex);
4642 static int swevent_hlist_get(struct perf_event *event)
4645 int cpu, failed_cpu;
4647 if (event->cpu != -1)
4648 return swevent_hlist_get_cpu(event, event->cpu);
4651 for_each_possible_cpu(cpu) {
4652 err = swevent_hlist_get_cpu(event, cpu);
4662 for_each_possible_cpu(cpu) {
4663 if (cpu == failed_cpu)
4665 swevent_hlist_put_cpu(event, cpu);
4672 atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
4674 static void sw_perf_event_destroy(struct perf_event *event)
4676 u64 event_id = event->attr.config;
4678 WARN_ON(event->parent);
4680 atomic_dec(&perf_swevent_enabled[event_id]);
4681 swevent_hlist_put(event);
4684 static int perf_swevent_init(struct perf_event *event)
4686 int event_id = event->attr.config;
4688 if (event->attr.type != PERF_TYPE_SOFTWARE)
4692 case PERF_COUNT_SW_CPU_CLOCK:
4693 case PERF_COUNT_SW_TASK_CLOCK:
4700 if (event_id > PERF_COUNT_SW_MAX)
4703 if (!event->parent) {
4706 err = swevent_hlist_get(event);
4710 atomic_inc(&perf_swevent_enabled[event_id]);
4711 event->destroy = sw_perf_event_destroy;
4717 static struct pmu perf_swevent = {
4718 .task_ctx_nr = perf_sw_context,
4720 .event_init = perf_swevent_init,
4721 .add = perf_swevent_add,
4722 .del = perf_swevent_del,
4723 .start = perf_swevent_start,
4724 .stop = perf_swevent_stop,
4725 .read = perf_swevent_read,
4728 #ifdef CONFIG_EVENT_TRACING
4730 static int perf_tp_filter_match(struct perf_event *event,
4731 struct perf_sample_data *data)
4733 void *record = data->raw->data;
4735 if (likely(!event->filter) || filter_match_preds(event->filter, record))
4740 static int perf_tp_event_match(struct perf_event *event,
4741 struct perf_sample_data *data,
4742 struct pt_regs *regs)
4745 * All tracepoints are from kernel-space.
4747 if (event->attr.exclude_kernel)
4750 if (!perf_tp_filter_match(event, data))
4756 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
4757 struct pt_regs *regs, struct hlist_head *head, int rctx)
4759 struct perf_sample_data data;
4760 struct perf_event *event;
4761 struct hlist_node *node;
4763 struct perf_raw_record raw = {
4768 perf_sample_data_init(&data, addr);
4771 hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
4772 if (perf_tp_event_match(event, &data, regs))
4773 perf_swevent_event(event, count, 1, &data, regs);
4776 perf_swevent_put_recursion_context(rctx);
4778 EXPORT_SYMBOL_GPL(perf_tp_event);
4780 static void tp_perf_event_destroy(struct perf_event *event)
4782 perf_trace_destroy(event);
4785 static int perf_tp_event_init(struct perf_event *event)
4789 if (event->attr.type != PERF_TYPE_TRACEPOINT)
4793 * Raw tracepoint data is a severe data leak, only allow root to
4796 if ((event->attr.sample_type & PERF_SAMPLE_RAW) &&
4797 perf_paranoid_tracepoint_raw() &&
4798 !capable(CAP_SYS_ADMIN))
4801 err = perf_trace_init(event);
4805 event->destroy = tp_perf_event_destroy;
4810 static struct pmu perf_tracepoint = {
4811 .task_ctx_nr = perf_sw_context,
4813 .event_init = perf_tp_event_init,
4814 .add = perf_trace_add,
4815 .del = perf_trace_del,
4816 .start = perf_swevent_start,
4817 .stop = perf_swevent_stop,
4818 .read = perf_swevent_read,
4821 static inline void perf_tp_register(void)
4823 perf_pmu_register(&perf_tracepoint);
4826 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4831 if (event->attr.type != PERF_TYPE_TRACEPOINT)
4834 filter_str = strndup_user(arg, PAGE_SIZE);
4835 if (IS_ERR(filter_str))
4836 return PTR_ERR(filter_str);
4838 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
4844 static void perf_event_free_filter(struct perf_event *event)
4846 ftrace_profile_free_filter(event);
4851 static inline void perf_tp_register(void)
4855 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4860 static void perf_event_free_filter(struct perf_event *event)
4864 #endif /* CONFIG_EVENT_TRACING */
4866 #ifdef CONFIG_HAVE_HW_BREAKPOINT
4867 void perf_bp_event(struct perf_event *bp, void *data)
4869 struct perf_sample_data sample;
4870 struct pt_regs *regs = data;
4872 perf_sample_data_init(&sample, bp->attr.bp_addr);
4874 if (!bp->hw.state && !perf_exclude_event(bp, regs))
4875 perf_swevent_event(bp, 1, 1, &sample, regs);
4880 * hrtimer based swevent callback
4883 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
4885 enum hrtimer_restart ret = HRTIMER_RESTART;
4886 struct perf_sample_data data;
4887 struct pt_regs *regs;
4888 struct perf_event *event;
4891 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
4892 event->pmu->read(event);
4894 perf_sample_data_init(&data, 0);
4895 data.period = event->hw.last_period;
4896 regs = get_irq_regs();
4898 if (regs && !perf_exclude_event(event, regs)) {
4899 if (!(event->attr.exclude_idle && current->pid == 0))
4900 if (perf_event_overflow(event, 0, &data, regs))
4901 ret = HRTIMER_NORESTART;
4904 period = max_t(u64, 10000, event->hw.sample_period);
4905 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
4910 static void perf_swevent_start_hrtimer(struct perf_event *event)
4912 struct hw_perf_event *hwc = &event->hw;
4914 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
4915 hwc->hrtimer.function = perf_swevent_hrtimer;
4916 if (hwc->sample_period) {
4917 s64 period = local64_read(&hwc->period_left);
4923 local64_set(&hwc->period_left, 0);
4925 period = max_t(u64, 10000, hwc->sample_period);
4927 __hrtimer_start_range_ns(&hwc->hrtimer,
4928 ns_to_ktime(period), 0,
4929 HRTIMER_MODE_REL_PINNED, 0);
4933 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
4935 struct hw_perf_event *hwc = &event->hw;
4937 if (hwc->sample_period) {
4938 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
4939 local64_set(&hwc->period_left, ktime_to_ns(remaining));
4941 hrtimer_cancel(&hwc->hrtimer);
4946 * Software event: cpu wall time clock
4949 static void cpu_clock_event_update(struct perf_event *event)
4954 now = local_clock();
4955 prev = local64_xchg(&event->hw.prev_count, now);
4956 local64_add(now - prev, &event->count);
4959 static void cpu_clock_event_start(struct perf_event *event, int flags)
4961 local64_set(&event->hw.prev_count, local_clock());
4962 perf_swevent_start_hrtimer(event);
4965 static void cpu_clock_event_stop(struct perf_event *event, int flags)
4967 perf_swevent_cancel_hrtimer(event);
4968 cpu_clock_event_update(event);
4971 static int cpu_clock_event_add(struct perf_event *event, int flags)
4973 if (flags & PERF_EF_START)
4974 cpu_clock_event_start(event, flags);
4979 static void cpu_clock_event_del(struct perf_event *event, int flags)
4981 cpu_clock_event_stop(event, flags);
4984 static void cpu_clock_event_read(struct perf_event *event)
4986 cpu_clock_event_update(event);
4989 static int cpu_clock_event_init(struct perf_event *event)
4991 if (event->attr.type != PERF_TYPE_SOFTWARE)
4994 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
5000 static struct pmu perf_cpu_clock = {
5001 .task_ctx_nr = perf_sw_context,
5003 .event_init = cpu_clock_event_init,
5004 .add = cpu_clock_event_add,
5005 .del = cpu_clock_event_del,
5006 .start = cpu_clock_event_start,
5007 .stop = cpu_clock_event_stop,
5008 .read = cpu_clock_event_read,
5012 * Software event: task time clock
5015 static void task_clock_event_update(struct perf_event *event, u64 now)
5020 prev = local64_xchg(&event->hw.prev_count, now);
5022 local64_add(delta, &event->count);
5025 static void task_clock_event_start(struct perf_event *event, int flags)
5027 local64_set(&event->hw.prev_count, event->ctx->time);
5028 perf_swevent_start_hrtimer(event);
5031 static void task_clock_event_stop(struct perf_event *event, int flags)
5033 perf_swevent_cancel_hrtimer(event);
5034 task_clock_event_update(event, event->ctx->time);
5037 static int task_clock_event_add(struct perf_event *event, int flags)
5039 if (flags & PERF_EF_START)
5040 task_clock_event_start(event, flags);
5045 static void task_clock_event_del(struct perf_event *event, int flags)
5047 task_clock_event_stop(event, PERF_EF_UPDATE);
5050 static void task_clock_event_read(struct perf_event *event)
5055 update_context_time(event->ctx);
5056 time = event->ctx->time;
5058 u64 now = perf_clock();
5059 u64 delta = now - event->ctx->timestamp;
5060 time = event->ctx->time + delta;
5063 task_clock_event_update(event, time);
5066 static int task_clock_event_init(struct perf_event *event)
5068 if (event->attr.type != PERF_TYPE_SOFTWARE)
5071 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
5077 static struct pmu perf_task_clock = {
5078 .task_ctx_nr = perf_sw_context,
5080 .event_init = task_clock_event_init,
5081 .add = task_clock_event_add,
5082 .del = task_clock_event_del,
5083 .start = task_clock_event_start,
5084 .stop = task_clock_event_stop,
5085 .read = task_clock_event_read,
5088 static void perf_pmu_nop_void(struct pmu *pmu)
5092 static int perf_pmu_nop_int(struct pmu *pmu)
5097 static void perf_pmu_start_txn(struct pmu *pmu)
5099 perf_pmu_disable(pmu);
5102 static int perf_pmu_commit_txn(struct pmu *pmu)
5104 perf_pmu_enable(pmu);
5108 static void perf_pmu_cancel_txn(struct pmu *pmu)
5110 perf_pmu_enable(pmu);
5114 * Ensures all contexts with the same task_ctx_nr have the same
5115 * pmu_cpu_context too.
5117 static void *find_pmu_context(int ctxn)
5124 list_for_each_entry(pmu, &pmus, entry) {
5125 if (pmu->task_ctx_nr == ctxn)
5126 return pmu->pmu_cpu_context;
5132 static void free_pmu_context(void * __percpu cpu_context)
5136 mutex_lock(&pmus_lock);
5138 * Like a real lame refcount.
5140 list_for_each_entry(pmu, &pmus, entry) {
5141 if (pmu->pmu_cpu_context == cpu_context)
5145 free_percpu(cpu_context);
5147 mutex_unlock(&pmus_lock);
5150 int perf_pmu_register(struct pmu *pmu)
5154 mutex_lock(&pmus_lock);
5156 pmu->pmu_disable_count = alloc_percpu(int);
5157 if (!pmu->pmu_disable_count)
5160 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
5161 if (pmu->pmu_cpu_context)
5162 goto got_cpu_context;
5164 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
5165 if (!pmu->pmu_cpu_context)
5168 for_each_possible_cpu(cpu) {
5169 struct perf_cpu_context *cpuctx;
5171 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
5172 __perf_event_init_context(&cpuctx->ctx);
5173 cpuctx->ctx.pmu = pmu;
5174 cpuctx->timer_interval = TICK_NSEC;
5175 hrtimer_init(&cpuctx->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
5176 cpuctx->timer.function = perf_event_context_tick;
5180 if (!pmu->start_txn) {
5181 if (pmu->pmu_enable) {
5183 * If we have pmu_enable/pmu_disable calls, install
5184 * transaction stubs that use that to try and batch
5185 * hardware accesses.
5187 pmu->start_txn = perf_pmu_start_txn;
5188 pmu->commit_txn = perf_pmu_commit_txn;
5189 pmu->cancel_txn = perf_pmu_cancel_txn;
5191 pmu->start_txn = perf_pmu_nop_void;
5192 pmu->commit_txn = perf_pmu_nop_int;
5193 pmu->cancel_txn = perf_pmu_nop_void;
5197 if (!pmu->pmu_enable) {
5198 pmu->pmu_enable = perf_pmu_nop_void;
5199 pmu->pmu_disable = perf_pmu_nop_void;
5202 list_add_rcu(&pmu->entry, &pmus);
5205 mutex_unlock(&pmus_lock);
5210 free_percpu(pmu->pmu_disable_count);
5214 void perf_pmu_unregister(struct pmu *pmu)
5216 mutex_lock(&pmus_lock);
5217 list_del_rcu(&pmu->entry);
5218 mutex_unlock(&pmus_lock);
5221 * We use the pmu list either under SRCU or preempt_disable,
5222 * synchronize_srcu() implies synchronize_sched() so we're good.
5224 synchronize_srcu(&pmus_srcu);
5226 free_percpu(pmu->pmu_disable_count);
5227 free_pmu_context(pmu->pmu_cpu_context);
5230 struct pmu *perf_init_event(struct perf_event *event)
5232 struct pmu *pmu = NULL;
5235 idx = srcu_read_lock(&pmus_srcu);
5236 list_for_each_entry_rcu(pmu, &pmus, entry) {
5237 int ret = pmu->event_init(event);
5240 if (ret != -ENOENT) {
5245 srcu_read_unlock(&pmus_srcu, idx);
5251 * Allocate and initialize a event structure
5253 static struct perf_event *
5254 perf_event_alloc(struct perf_event_attr *attr, int cpu,
5255 struct perf_event *group_leader,
5256 struct perf_event *parent_event,
5257 perf_overflow_handler_t overflow_handler)
5260 struct perf_event *event;
5261 struct hw_perf_event *hwc;
5264 event = kzalloc(sizeof(*event), GFP_KERNEL);
5266 return ERR_PTR(-ENOMEM);
5269 * Single events are their own group leaders, with an
5270 * empty sibling list:
5273 group_leader = event;
5275 mutex_init(&event->child_mutex);
5276 INIT_LIST_HEAD(&event->child_list);
5278 INIT_LIST_HEAD(&event->group_entry);
5279 INIT_LIST_HEAD(&event->event_entry);
5280 INIT_LIST_HEAD(&event->sibling_list);
5281 init_waitqueue_head(&event->waitq);
5283 mutex_init(&event->mmap_mutex);
5286 event->attr = *attr;
5287 event->group_leader = group_leader;
5291 event->parent = parent_event;
5293 event->ns = get_pid_ns(current->nsproxy->pid_ns);
5294 event->id = atomic64_inc_return(&perf_event_id);
5296 event->state = PERF_EVENT_STATE_INACTIVE;
5298 if (!overflow_handler && parent_event)
5299 overflow_handler = parent_event->overflow_handler;
5301 event->overflow_handler = overflow_handler;
5304 event->state = PERF_EVENT_STATE_OFF;
5309 hwc->sample_period = attr->sample_period;
5310 if (attr->freq && attr->sample_freq)
5311 hwc->sample_period = 1;
5312 hwc->last_period = hwc->sample_period;
5314 local64_set(&hwc->period_left, hwc->sample_period);
5317 * we currently do not support PERF_FORMAT_GROUP on inherited events
5319 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
5322 pmu = perf_init_event(event);
5328 else if (IS_ERR(pmu))
5333 put_pid_ns(event->ns);
5335 return ERR_PTR(err);
5340 if (!event->parent) {
5341 atomic_inc(&nr_events);
5342 if (event->attr.mmap || event->attr.mmap_data)
5343 atomic_inc(&nr_mmap_events);
5344 if (event->attr.comm)
5345 atomic_inc(&nr_comm_events);
5346 if (event->attr.task)
5347 atomic_inc(&nr_task_events);
5348 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
5349 err = get_callchain_buffers();
5352 return ERR_PTR(err);
5360 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5361 struct perf_event_attr *attr)
5366 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
5370 * zero the full structure, so that a short copy will be nice.
5372 memset(attr, 0, sizeof(*attr));
5374 ret = get_user(size, &uattr->size);
5378 if (size > PAGE_SIZE) /* silly large */
5381 if (!size) /* abi compat */
5382 size = PERF_ATTR_SIZE_VER0;
5384 if (size < PERF_ATTR_SIZE_VER0)
5388 * If we're handed a bigger struct than we know of,
5389 * ensure all the unknown bits are 0 - i.e. new
5390 * user-space does not rely on any kernel feature
5391 * extensions we dont know about yet.
5393 if (size > sizeof(*attr)) {
5394 unsigned char __user *addr;
5395 unsigned char __user *end;
5398 addr = (void __user *)uattr + sizeof(*attr);
5399 end = (void __user *)uattr + size;
5401 for (; addr < end; addr++) {
5402 ret = get_user(val, addr);
5408 size = sizeof(*attr);
5411 ret = copy_from_user(attr, uattr, size);
5416 * If the type exists, the corresponding creation will verify
5419 if (attr->type >= PERF_TYPE_MAX)
5422 if (attr->__reserved_1)
5425 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
5428 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
5435 put_user(sizeof(*attr), &uattr->size);
5441 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
5443 struct perf_buffer *buffer = NULL, *old_buffer = NULL;
5449 /* don't allow circular references */
5450 if (event == output_event)
5454 * Don't allow cross-cpu buffers
5456 if (output_event->cpu != event->cpu)
5460 * If its not a per-cpu buffer, it must be the same task.
5462 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
5466 mutex_lock(&event->mmap_mutex);
5467 /* Can't redirect output if we've got an active mmap() */
5468 if (atomic_read(&event->mmap_count))
5472 /* get the buffer we want to redirect to */
5473 buffer = perf_buffer_get(output_event);
5478 old_buffer = event->buffer;
5479 rcu_assign_pointer(event->buffer, buffer);
5482 mutex_unlock(&event->mmap_mutex);
5485 perf_buffer_put(old_buffer);
5491 * sys_perf_event_open - open a performance event, associate it to a task/cpu
5493 * @attr_uptr: event_id type attributes for monitoring/sampling
5496 * @group_fd: group leader event fd
5498 SYSCALL_DEFINE5(perf_event_open,
5499 struct perf_event_attr __user *, attr_uptr,
5500 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
5502 struct perf_event *event, *group_leader = NULL, *output_event = NULL;
5503 struct perf_event_attr attr;
5504 struct perf_event_context *ctx;
5505 struct file *event_file = NULL;
5506 struct file *group_file = NULL;
5509 int fput_needed = 0;
5512 /* for future expandability... */
5513 if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT))
5516 err = perf_copy_attr(attr_uptr, &attr);
5520 if (!attr.exclude_kernel) {
5521 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
5526 if (attr.sample_freq > sysctl_perf_event_sample_rate)
5530 event_fd = get_unused_fd_flags(O_RDWR);
5534 event = perf_event_alloc(&attr, cpu, group_leader, NULL, NULL);
5535 if (IS_ERR(event)) {
5536 err = PTR_ERR(event);
5540 if (group_fd != -1) {
5541 group_leader = perf_fget_light(group_fd, &fput_needed);
5542 if (IS_ERR(group_leader)) {
5543 err = PTR_ERR(group_leader);
5546 group_file = group_leader->filp;
5547 if (flags & PERF_FLAG_FD_OUTPUT)
5548 output_event = group_leader;
5549 if (flags & PERF_FLAG_FD_NO_GROUP)
5550 group_leader = NULL;
5554 * Special case software events and allow them to be part of
5555 * any hardware group.
5558 if ((pmu->task_ctx_nr == perf_sw_context) && group_leader)
5559 pmu = group_leader->pmu;
5562 * Get the target context (task or percpu):
5564 ctx = find_get_context(pmu, pid, cpu);
5571 * Look up the group leader (we will attach this event to it):
5577 * Do not allow a recursive hierarchy (this new sibling
5578 * becoming part of another group-sibling):
5580 if (group_leader->group_leader != group_leader)
5583 * Do not allow to attach to a group in a different
5584 * task or CPU context:
5586 if (group_leader->ctx != ctx)
5589 * Only a group leader can be exclusive or pinned
5591 if (attr.exclusive || attr.pinned)
5596 err = perf_event_set_output(event, output_event);
5601 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR);
5602 if (IS_ERR(event_file)) {
5603 err = PTR_ERR(event_file);
5607 event->filp = event_file;
5608 WARN_ON_ONCE(ctx->parent_ctx);
5609 mutex_lock(&ctx->mutex);
5610 perf_install_in_context(ctx, event, cpu);
5612 mutex_unlock(&ctx->mutex);
5614 event->owner = current;
5615 get_task_struct(current);
5616 mutex_lock(¤t->perf_event_mutex);
5617 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
5618 mutex_unlock(¤t->perf_event_mutex);
5621 * Drop the reference on the group_event after placing the
5622 * new event on the sibling_list. This ensures destruction
5623 * of the group leader will find the pointer to itself in
5624 * perf_group_detach().
5626 fput_light(group_file, fput_needed);
5627 fd_install(event_fd, event_file);
5633 fput_light(group_file, fput_needed);
5637 put_unused_fd(event_fd);
5642 * perf_event_create_kernel_counter
5644 * @attr: attributes of the counter to create
5645 * @cpu: cpu in which the counter is bound
5646 * @pid: task to profile
5649 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
5651 perf_overflow_handler_t overflow_handler)
5653 struct perf_event_context *ctx;
5654 struct perf_event *event;
5658 * Get the target context (task or percpu):
5661 event = perf_event_alloc(attr, cpu, NULL, NULL, overflow_handler);
5662 if (IS_ERR(event)) {
5663 err = PTR_ERR(event);
5667 ctx = find_get_context(event->pmu, pid, cpu);
5674 WARN_ON_ONCE(ctx->parent_ctx);
5675 mutex_lock(&ctx->mutex);
5676 perf_install_in_context(ctx, event, cpu);
5678 mutex_unlock(&ctx->mutex);
5680 event->owner = current;
5681 get_task_struct(current);
5682 mutex_lock(¤t->perf_event_mutex);
5683 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
5684 mutex_unlock(¤t->perf_event_mutex);
5691 return ERR_PTR(err);
5693 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
5695 static void sync_child_event(struct perf_event *child_event,
5696 struct task_struct *child)
5698 struct perf_event *parent_event = child_event->parent;
5701 if (child_event->attr.inherit_stat)
5702 perf_event_read_event(child_event, child);
5704 child_val = perf_event_count(child_event);
5707 * Add back the child's count to the parent's count:
5709 atomic64_add(child_val, &parent_event->child_count);
5710 atomic64_add(child_event->total_time_enabled,
5711 &parent_event->child_total_time_enabled);
5712 atomic64_add(child_event->total_time_running,
5713 &parent_event->child_total_time_running);
5716 * Remove this event from the parent's list
5718 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
5719 mutex_lock(&parent_event->child_mutex);
5720 list_del_init(&child_event->child_list);
5721 mutex_unlock(&parent_event->child_mutex);
5724 * Release the parent event, if this was the last
5727 fput(parent_event->filp);
5731 __perf_event_exit_task(struct perf_event *child_event,
5732 struct perf_event_context *child_ctx,
5733 struct task_struct *child)
5735 struct perf_event *parent_event;
5737 perf_event_remove_from_context(child_event);
5739 parent_event = child_event->parent;
5741 * It can happen that parent exits first, and has events
5742 * that are still around due to the child reference. These
5743 * events need to be zapped - but otherwise linger.
5746 sync_child_event(child_event, child);
5747 free_event(child_event);
5751 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
5753 struct perf_event *child_event, *tmp;
5754 struct perf_event_context *child_ctx;
5755 unsigned long flags;
5757 if (likely(!child->perf_event_ctxp[ctxn])) {
5758 perf_event_task(child, NULL, 0);
5762 local_irq_save(flags);
5764 * We can't reschedule here because interrupts are disabled,
5765 * and either child is current or it is a task that can't be
5766 * scheduled, so we are now safe from rescheduling changing
5769 child_ctx = child->perf_event_ctxp[ctxn];
5770 __perf_event_task_sched_out(child_ctx);
5773 * Take the context lock here so that if find_get_context is
5774 * reading child->perf_event_ctxp, we wait until it has
5775 * incremented the context's refcount before we do put_ctx below.
5777 raw_spin_lock(&child_ctx->lock);
5778 child->perf_event_ctxp[ctxn] = NULL;
5780 * If this context is a clone; unclone it so it can't get
5781 * swapped to another process while we're removing all
5782 * the events from it.
5784 unclone_ctx(child_ctx);
5785 update_context_time(child_ctx);
5786 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
5789 * Report the task dead after unscheduling the events so that we
5790 * won't get any samples after PERF_RECORD_EXIT. We can however still
5791 * get a few PERF_RECORD_READ events.
5793 perf_event_task(child, child_ctx, 0);
5796 * We can recurse on the same lock type through:
5798 * __perf_event_exit_task()
5799 * sync_child_event()
5800 * fput(parent_event->filp)
5802 * mutex_lock(&ctx->mutex)
5804 * But since its the parent context it won't be the same instance.
5806 mutex_lock(&child_ctx->mutex);
5809 list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
5811 __perf_event_exit_task(child_event, child_ctx, child);
5813 list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
5815 __perf_event_exit_task(child_event, child_ctx, child);
5818 * If the last event was a group event, it will have appended all
5819 * its siblings to the list, but we obtained 'tmp' before that which
5820 * will still point to the list head terminating the iteration.
5822 if (!list_empty(&child_ctx->pinned_groups) ||
5823 !list_empty(&child_ctx->flexible_groups))
5826 mutex_unlock(&child_ctx->mutex);
5832 * When a child task exits, feed back event values to parent events.
5834 void perf_event_exit_task(struct task_struct *child)
5838 for_each_task_context_nr(ctxn)
5839 perf_event_exit_task_context(child, ctxn);
5842 static void perf_free_event(struct perf_event *event,
5843 struct perf_event_context *ctx)
5845 struct perf_event *parent = event->parent;
5847 if (WARN_ON_ONCE(!parent))
5850 mutex_lock(&parent->child_mutex);
5851 list_del_init(&event->child_list);
5852 mutex_unlock(&parent->child_mutex);
5856 perf_group_detach(event);
5857 list_del_event(event, ctx);
5862 * free an unexposed, unused context as created by inheritance by
5863 * perf_event_init_task below, used by fork() in case of fail.
5865 void perf_event_free_task(struct task_struct *task)
5867 struct perf_event_context *ctx;
5868 struct perf_event *event, *tmp;
5871 for_each_task_context_nr(ctxn) {
5872 ctx = task->perf_event_ctxp[ctxn];
5876 mutex_lock(&ctx->mutex);
5878 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
5880 perf_free_event(event, ctx);
5882 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
5884 perf_free_event(event, ctx);
5886 if (!list_empty(&ctx->pinned_groups) ||
5887 !list_empty(&ctx->flexible_groups))
5890 mutex_unlock(&ctx->mutex);
5896 void perf_event_delayed_put(struct task_struct *task)
5900 for_each_task_context_nr(ctxn)
5901 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
5905 * inherit a event from parent task to child task:
5907 static struct perf_event *
5908 inherit_event(struct perf_event *parent_event,
5909 struct task_struct *parent,
5910 struct perf_event_context *parent_ctx,
5911 struct task_struct *child,
5912 struct perf_event *group_leader,
5913 struct perf_event_context *child_ctx)
5915 struct perf_event *child_event;
5918 * Instead of creating recursive hierarchies of events,
5919 * we link inherited events back to the original parent,
5920 * which has a filp for sure, which we use as the reference
5923 if (parent_event->parent)
5924 parent_event = parent_event->parent;
5926 child_event = perf_event_alloc(&parent_event->attr,
5928 group_leader, parent_event,
5930 if (IS_ERR(child_event))
5935 * Make the child state follow the state of the parent event,
5936 * not its attr.disabled bit. We hold the parent's mutex,
5937 * so we won't race with perf_event_{en, dis}able_family.
5939 if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
5940 child_event->state = PERF_EVENT_STATE_INACTIVE;
5942 child_event->state = PERF_EVENT_STATE_OFF;
5944 if (parent_event->attr.freq) {
5945 u64 sample_period = parent_event->hw.sample_period;
5946 struct hw_perf_event *hwc = &child_event->hw;
5948 hwc->sample_period = sample_period;
5949 hwc->last_period = sample_period;
5951 local64_set(&hwc->period_left, sample_period);
5954 child_event->ctx = child_ctx;
5955 child_event->overflow_handler = parent_event->overflow_handler;
5958 * Link it up in the child's context:
5960 add_event_to_ctx(child_event, child_ctx);
5963 * Get a reference to the parent filp - we will fput it
5964 * when the child event exits. This is safe to do because
5965 * we are in the parent and we know that the filp still
5966 * exists and has a nonzero count:
5968 atomic_long_inc(&parent_event->filp->f_count);
5971 * Link this into the parent event's child list
5973 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
5974 mutex_lock(&parent_event->child_mutex);
5975 list_add_tail(&child_event->child_list, &parent_event->child_list);
5976 mutex_unlock(&parent_event->child_mutex);
5981 static int inherit_group(struct perf_event *parent_event,
5982 struct task_struct *parent,
5983 struct perf_event_context *parent_ctx,
5984 struct task_struct *child,
5985 struct perf_event_context *child_ctx)
5987 struct perf_event *leader;
5988 struct perf_event *sub;
5989 struct perf_event *child_ctr;
5991 leader = inherit_event(parent_event, parent, parent_ctx,
5992 child, NULL, child_ctx);
5994 return PTR_ERR(leader);
5995 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
5996 child_ctr = inherit_event(sub, parent, parent_ctx,
5997 child, leader, child_ctx);
5998 if (IS_ERR(child_ctr))
5999 return PTR_ERR(child_ctr);
6005 inherit_task_group(struct perf_event *event, struct task_struct *parent,
6006 struct perf_event_context *parent_ctx,
6007 struct task_struct *child, int ctxn,
6011 struct perf_event_context *child_ctx;
6013 if (!event->attr.inherit) {
6018 child_ctx = child->perf_event_ctxp[ctxn];
6021 * This is executed from the parent task context, so
6022 * inherit events that have been marked for cloning.
6023 * First allocate and initialize a context for the
6027 child_ctx = alloc_perf_context(event->pmu, child);
6031 child->perf_event_ctxp[ctxn] = child_ctx;
6034 ret = inherit_group(event, parent, parent_ctx,
6044 * Initialize the perf_event context in task_struct
6046 int perf_event_init_context(struct task_struct *child, int ctxn)
6048 struct perf_event_context *child_ctx, *parent_ctx;
6049 struct perf_event_context *cloned_ctx;
6050 struct perf_event *event;
6051 struct task_struct *parent = current;
6052 int inherited_all = 1;
6055 child->perf_event_ctxp[ctxn] = NULL;
6057 mutex_init(&child->perf_event_mutex);
6058 INIT_LIST_HEAD(&child->perf_event_list);
6060 if (likely(!parent->perf_event_ctxp[ctxn]))
6064 * If the parent's context is a clone, pin it so it won't get
6067 parent_ctx = perf_pin_task_context(parent, ctxn);
6070 * No need to check if parent_ctx != NULL here; since we saw
6071 * it non-NULL earlier, the only reason for it to become NULL
6072 * is if we exit, and since we're currently in the middle of
6073 * a fork we can't be exiting at the same time.
6077 * Lock the parent list. No need to lock the child - not PID
6078 * hashed yet and not running, so nobody can access it.
6080 mutex_lock(&parent_ctx->mutex);
6083 * We dont have to disable NMIs - we are only looking at
6084 * the list, not manipulating it:
6086 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
6087 ret = inherit_task_group(event, parent, parent_ctx,
6088 child, ctxn, &inherited_all);
6093 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
6094 ret = inherit_task_group(event, parent, parent_ctx,
6095 child, ctxn, &inherited_all);
6100 child_ctx = child->perf_event_ctxp[ctxn];
6102 if (child_ctx && inherited_all) {
6104 * Mark the child context as a clone of the parent
6105 * context, or of whatever the parent is a clone of.
6106 * Note that if the parent is a clone, it could get
6107 * uncloned at any point, but that doesn't matter
6108 * because the list of events and the generation
6109 * count can't have changed since we took the mutex.
6111 cloned_ctx = rcu_dereference(parent_ctx->parent_ctx);
6113 child_ctx->parent_ctx = cloned_ctx;
6114 child_ctx->parent_gen = parent_ctx->parent_gen;
6116 child_ctx->parent_ctx = parent_ctx;
6117 child_ctx->parent_gen = parent_ctx->generation;
6119 get_ctx(child_ctx->parent_ctx);
6122 mutex_unlock(&parent_ctx->mutex);
6124 perf_unpin_context(parent_ctx);
6130 * Initialize the perf_event context in task_struct
6132 int perf_event_init_task(struct task_struct *child)
6136 for_each_task_context_nr(ctxn) {
6137 ret = perf_event_init_context(child, ctxn);
6145 static void __init perf_event_init_all_cpus(void)
6147 struct swevent_htable *swhash;
6150 for_each_possible_cpu(cpu) {
6151 swhash = &per_cpu(swevent_htable, cpu);
6152 mutex_init(&swhash->hlist_mutex);
6156 static void __cpuinit perf_event_init_cpu(int cpu)
6158 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6160 mutex_lock(&swhash->hlist_mutex);
6161 if (swhash->hlist_refcount > 0) {
6162 struct swevent_hlist *hlist;
6164 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
6166 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6168 mutex_unlock(&swhash->hlist_mutex);
6171 #ifdef CONFIG_HOTPLUG_CPU
6172 static void __perf_event_exit_context(void *__info)
6174 struct perf_event_context *ctx = __info;
6175 struct perf_event *event, *tmp;
6177 perf_pmu_rotate_stop(ctx->pmu);
6179 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
6180 __perf_event_remove_from_context(event);
6181 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry)
6182 __perf_event_remove_from_context(event);
6185 static void perf_event_exit_cpu_context(int cpu)
6187 struct perf_event_context *ctx;
6191 idx = srcu_read_lock(&pmus_srcu);
6192 list_for_each_entry_rcu(pmu, &pmus, entry) {
6193 ctx = &this_cpu_ptr(pmu->pmu_cpu_context)->ctx;
6195 mutex_lock(&ctx->mutex);
6196 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
6197 mutex_unlock(&ctx->mutex);
6199 srcu_read_unlock(&pmus_srcu, idx);
6203 static void perf_event_exit_cpu(int cpu)
6205 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6207 mutex_lock(&swhash->hlist_mutex);
6208 swevent_hlist_release(swhash);
6209 mutex_unlock(&swhash->hlist_mutex);
6211 perf_event_exit_cpu_context(cpu);
6214 static inline void perf_event_exit_cpu(int cpu) { }
6217 static int __cpuinit
6218 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
6220 unsigned int cpu = (long)hcpu;
6222 switch (action & ~CPU_TASKS_FROZEN) {
6224 case CPU_UP_PREPARE:
6225 case CPU_DOWN_FAILED:
6226 perf_event_init_cpu(cpu);
6229 case CPU_UP_CANCELED:
6230 case CPU_DOWN_PREPARE:
6231 perf_event_exit_cpu(cpu);
6241 void __init perf_event_init(void)
6243 perf_event_init_all_cpus();
6244 init_srcu_struct(&pmus_srcu);
6245 perf_pmu_register(&perf_swevent);
6246 perf_pmu_register(&perf_cpu_clock);
6247 perf_pmu_register(&perf_task_clock);
6249 perf_cpu_notifier(perf_cpu_notify);