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/sysfs.h>
19 #include <linux/dcache.h>
20 #include <linux/percpu.h>
21 #include <linux/ptrace.h>
22 #include <linux/vmstat.h>
23 #include <linux/vmalloc.h>
24 #include <linux/hardirq.h>
25 #include <linux/rculist.h>
26 #include <linux/uaccess.h>
27 #include <linux/syscalls.h>
28 #include <linux/anon_inodes.h>
29 #include <linux/kernel_stat.h>
30 #include <linux/perf_event.h>
31 #include <linux/ftrace_event.h>
32 #include <linux/hw_breakpoint.h>
34 #include <asm/irq_regs.h>
37 * Each CPU has a list of per CPU events:
39 static DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context);
41 int perf_max_events __read_mostly = 1;
42 static int perf_reserved_percpu __read_mostly;
43 static int perf_overcommit __read_mostly = 1;
45 static atomic_t nr_events __read_mostly;
46 static atomic_t nr_mmap_events __read_mostly;
47 static atomic_t nr_comm_events __read_mostly;
48 static atomic_t nr_task_events __read_mostly;
51 * perf event paranoia level:
52 * -1 - not paranoid at all
53 * 0 - disallow raw tracepoint access for unpriv
54 * 1 - disallow cpu events for unpriv
55 * 2 - disallow kernel profiling for unpriv
57 int sysctl_perf_event_paranoid __read_mostly = 1;
59 static inline bool perf_paranoid_tracepoint_raw(void)
61 return sysctl_perf_event_paranoid > -1;
64 static inline bool perf_paranoid_cpu(void)
66 return sysctl_perf_event_paranoid > 0;
69 static inline bool perf_paranoid_kernel(void)
71 return sysctl_perf_event_paranoid > 1;
74 int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
77 * max perf event sample rate
79 int sysctl_perf_event_sample_rate __read_mostly = 100000;
81 static atomic64_t perf_event_id;
84 * Lock for (sysadmin-configurable) event reservations:
86 static DEFINE_SPINLOCK(perf_resource_lock);
89 * Architecture provided APIs - weak aliases:
91 extern __weak const struct pmu *hw_perf_event_init(struct perf_event *event)
96 void __weak hw_perf_disable(void) { barrier(); }
97 void __weak hw_perf_enable(void) { barrier(); }
99 void __weak hw_perf_event_setup(int cpu) { barrier(); }
100 void __weak hw_perf_event_setup_online(int cpu) { barrier(); }
101 void __weak hw_perf_event_setup_offline(int cpu) { barrier(); }
104 hw_perf_group_sched_in(struct perf_event *group_leader,
105 struct perf_cpu_context *cpuctx,
106 struct perf_event_context *ctx, int cpu)
111 void __weak perf_event_print_debug(void) { }
113 static DEFINE_PER_CPU(int, perf_disable_count);
115 void __perf_disable(void)
117 __get_cpu_var(perf_disable_count)++;
120 bool __perf_enable(void)
122 return !--__get_cpu_var(perf_disable_count);
125 void perf_disable(void)
131 void perf_enable(void)
137 static void get_ctx(struct perf_event_context *ctx)
139 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
142 static void free_ctx(struct rcu_head *head)
144 struct perf_event_context *ctx;
146 ctx = container_of(head, struct perf_event_context, rcu_head);
150 static void put_ctx(struct perf_event_context *ctx)
152 if (atomic_dec_and_test(&ctx->refcount)) {
154 put_ctx(ctx->parent_ctx);
156 put_task_struct(ctx->task);
157 call_rcu(&ctx->rcu_head, free_ctx);
161 static void unclone_ctx(struct perf_event_context *ctx)
163 if (ctx->parent_ctx) {
164 put_ctx(ctx->parent_ctx);
165 ctx->parent_ctx = NULL;
170 * If we inherit events we want to return the parent event id
173 static u64 primary_event_id(struct perf_event *event)
178 id = event->parent->id;
184 * Get the perf_event_context for a task and lock it.
185 * This has to cope with with the fact that until it is locked,
186 * the context could get moved to another task.
188 static struct perf_event_context *
189 perf_lock_task_context(struct task_struct *task, unsigned long *flags)
191 struct perf_event_context *ctx;
195 ctx = rcu_dereference(task->perf_event_ctxp);
198 * If this context is a clone of another, it might
199 * get swapped for another underneath us by
200 * perf_event_task_sched_out, though the
201 * rcu_read_lock() protects us from any context
202 * getting freed. Lock the context and check if it
203 * got swapped before we could get the lock, and retry
204 * if so. If we locked the right context, then it
205 * can't get swapped on us any more.
207 raw_spin_lock_irqsave(&ctx->lock, *flags);
208 if (ctx != rcu_dereference(task->perf_event_ctxp)) {
209 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
213 if (!atomic_inc_not_zero(&ctx->refcount)) {
214 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
223 * Get the context for a task and increment its pin_count so it
224 * can't get swapped to another task. This also increments its
225 * reference count so that the context can't get freed.
227 static struct perf_event_context *perf_pin_task_context(struct task_struct *task)
229 struct perf_event_context *ctx;
232 ctx = perf_lock_task_context(task, &flags);
235 raw_spin_unlock_irqrestore(&ctx->lock, flags);
240 static void perf_unpin_context(struct perf_event_context *ctx)
244 raw_spin_lock_irqsave(&ctx->lock, flags);
246 raw_spin_unlock_irqrestore(&ctx->lock, flags);
250 static inline u64 perf_clock(void)
252 return cpu_clock(smp_processor_id());
256 * Update the record of the current time in a context.
258 static void update_context_time(struct perf_event_context *ctx)
260 u64 now = perf_clock();
262 ctx->time += now - ctx->timestamp;
263 ctx->timestamp = now;
267 * Update the total_time_enabled and total_time_running fields for a event.
269 static void update_event_times(struct perf_event *event)
271 struct perf_event_context *ctx = event->ctx;
274 if (event->state < PERF_EVENT_STATE_INACTIVE ||
275 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
281 run_end = event->tstamp_stopped;
283 event->total_time_enabled = run_end - event->tstamp_enabled;
285 if (event->state == PERF_EVENT_STATE_INACTIVE)
286 run_end = event->tstamp_stopped;
290 event->total_time_running = run_end - event->tstamp_running;
293 static struct list_head *
294 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
296 if (event->attr.pinned)
297 return &ctx->pinned_groups;
299 return &ctx->flexible_groups;
303 * Add a event from the lists for its context.
304 * Must be called with ctx->mutex and ctx->lock held.
307 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
309 struct perf_event *group_leader = event->group_leader;
312 * Depending on whether it is a standalone or sibling event,
313 * add it straight to the context's event list, or to the group
314 * leader's sibling list:
316 if (group_leader == event) {
317 struct list_head *list;
319 if (is_software_event(event))
320 event->group_flags |= PERF_GROUP_SOFTWARE;
322 list = ctx_group_list(event, ctx);
323 list_add_tail(&event->group_entry, list);
325 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
326 !is_software_event(event))
327 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
329 list_add_tail(&event->group_entry, &group_leader->sibling_list);
330 group_leader->nr_siblings++;
333 list_add_rcu(&event->event_entry, &ctx->event_list);
335 if (event->attr.inherit_stat)
340 * Remove a event from the lists for its context.
341 * Must be called with ctx->mutex and ctx->lock held.
344 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
346 struct perf_event *sibling, *tmp;
348 if (list_empty(&event->group_entry))
351 if (event->attr.inherit_stat)
354 list_del_init(&event->group_entry);
355 list_del_rcu(&event->event_entry);
357 if (event->group_leader != event)
358 event->group_leader->nr_siblings--;
360 update_event_times(event);
363 * If event was in error state, then keep it
364 * that way, otherwise bogus counts will be
365 * returned on read(). The only way to get out
366 * of error state is by explicit re-enabling
369 if (event->state > PERF_EVENT_STATE_OFF)
370 event->state = PERF_EVENT_STATE_OFF;
373 * If this was a group event with sibling events then
374 * upgrade the siblings to singleton events by adding them
375 * to the context list directly:
377 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
378 struct list_head *list;
380 list = ctx_group_list(event, ctx);
381 list_move_tail(&sibling->group_entry, list);
382 sibling->group_leader = sibling;
384 /* Inherit group flags from the previous leader */
385 sibling->group_flags = event->group_flags;
390 event_sched_out(struct perf_event *event,
391 struct perf_cpu_context *cpuctx,
392 struct perf_event_context *ctx)
394 if (event->state != PERF_EVENT_STATE_ACTIVE)
397 event->state = PERF_EVENT_STATE_INACTIVE;
398 if (event->pending_disable) {
399 event->pending_disable = 0;
400 event->state = PERF_EVENT_STATE_OFF;
402 event->tstamp_stopped = ctx->time;
403 event->pmu->disable(event);
406 if (!is_software_event(event))
407 cpuctx->active_oncpu--;
409 if (event->attr.exclusive || !cpuctx->active_oncpu)
410 cpuctx->exclusive = 0;
414 group_sched_out(struct perf_event *group_event,
415 struct perf_cpu_context *cpuctx,
416 struct perf_event_context *ctx)
418 struct perf_event *event;
420 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
423 event_sched_out(group_event, cpuctx, ctx);
426 * Schedule out siblings (if any):
428 list_for_each_entry(event, &group_event->sibling_list, group_entry)
429 event_sched_out(event, cpuctx, ctx);
431 if (group_event->attr.exclusive)
432 cpuctx->exclusive = 0;
436 * Cross CPU call to remove a performance event
438 * We disable the event on the hardware level first. After that we
439 * remove it from the context list.
441 static void __perf_event_remove_from_context(void *info)
443 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
444 struct perf_event *event = info;
445 struct perf_event_context *ctx = event->ctx;
448 * If this is a task context, we need to check whether it is
449 * the current task context of this cpu. If not it has been
450 * scheduled out before the smp call arrived.
452 if (ctx->task && cpuctx->task_ctx != ctx)
455 raw_spin_lock(&ctx->lock);
457 * Protect the list operation against NMI by disabling the
458 * events on a global level.
462 event_sched_out(event, cpuctx, ctx);
464 list_del_event(event, ctx);
468 * Allow more per task events with respect to the
471 cpuctx->max_pertask =
472 min(perf_max_events - ctx->nr_events,
473 perf_max_events - perf_reserved_percpu);
477 raw_spin_unlock(&ctx->lock);
482 * Remove the event from a task's (or a CPU's) list of events.
484 * Must be called with ctx->mutex held.
486 * CPU events are removed with a smp call. For task events we only
487 * call when the task is on a CPU.
489 * If event->ctx is a cloned context, callers must make sure that
490 * every task struct that event->ctx->task could possibly point to
491 * remains valid. This is OK when called from perf_release since
492 * that only calls us on the top-level context, which can't be a clone.
493 * When called from perf_event_exit_task, it's OK because the
494 * context has been detached from its task.
496 static void perf_event_remove_from_context(struct perf_event *event)
498 struct perf_event_context *ctx = event->ctx;
499 struct task_struct *task = ctx->task;
503 * Per cpu events are removed via an smp call and
504 * the removal is always successful.
506 smp_call_function_single(event->cpu,
507 __perf_event_remove_from_context,
513 task_oncpu_function_call(task, __perf_event_remove_from_context,
516 raw_spin_lock_irq(&ctx->lock);
518 * If the context is active we need to retry the smp call.
520 if (ctx->nr_active && !list_empty(&event->group_entry)) {
521 raw_spin_unlock_irq(&ctx->lock);
526 * The lock prevents that this context is scheduled in so we
527 * can remove the event safely, if the call above did not
530 if (!list_empty(&event->group_entry))
531 list_del_event(event, ctx);
532 raw_spin_unlock_irq(&ctx->lock);
536 * Update total_time_enabled and total_time_running for all events in a group.
538 static void update_group_times(struct perf_event *leader)
540 struct perf_event *event;
542 update_event_times(leader);
543 list_for_each_entry(event, &leader->sibling_list, group_entry)
544 update_event_times(event);
548 * Cross CPU call to disable a performance event
550 static void __perf_event_disable(void *info)
552 struct perf_event *event = info;
553 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
554 struct perf_event_context *ctx = event->ctx;
557 * If this is a per-task event, need to check whether this
558 * event's task is the current task on this cpu.
560 if (ctx->task && cpuctx->task_ctx != ctx)
563 raw_spin_lock(&ctx->lock);
566 * If the event is on, turn it off.
567 * If it is in error state, leave it in error state.
569 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
570 update_context_time(ctx);
571 update_group_times(event);
572 if (event == event->group_leader)
573 group_sched_out(event, cpuctx, ctx);
575 event_sched_out(event, cpuctx, ctx);
576 event->state = PERF_EVENT_STATE_OFF;
579 raw_spin_unlock(&ctx->lock);
585 * If event->ctx is a cloned context, callers must make sure that
586 * every task struct that event->ctx->task could possibly point to
587 * remains valid. This condition is satisifed when called through
588 * perf_event_for_each_child or perf_event_for_each because they
589 * hold the top-level event's child_mutex, so any descendant that
590 * goes to exit will block in sync_child_event.
591 * When called from perf_pending_event it's OK because event->ctx
592 * is the current context on this CPU and preemption is disabled,
593 * hence we can't get into perf_event_task_sched_out for this context.
595 void perf_event_disable(struct perf_event *event)
597 struct perf_event_context *ctx = event->ctx;
598 struct task_struct *task = ctx->task;
602 * Disable the event on the cpu that it's on
604 smp_call_function_single(event->cpu, __perf_event_disable,
610 task_oncpu_function_call(task, __perf_event_disable, event);
612 raw_spin_lock_irq(&ctx->lock);
614 * If the event is still active, we need to retry the cross-call.
616 if (event->state == PERF_EVENT_STATE_ACTIVE) {
617 raw_spin_unlock_irq(&ctx->lock);
622 * Since we have the lock this context can't be scheduled
623 * in, so we can change the state safely.
625 if (event->state == PERF_EVENT_STATE_INACTIVE) {
626 update_group_times(event);
627 event->state = PERF_EVENT_STATE_OFF;
630 raw_spin_unlock_irq(&ctx->lock);
634 event_sched_in(struct perf_event *event,
635 struct perf_cpu_context *cpuctx,
636 struct perf_event_context *ctx,
639 if (event->state <= PERF_EVENT_STATE_OFF)
642 event->state = PERF_EVENT_STATE_ACTIVE;
643 event->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */
645 * The new state must be visible before we turn it on in the hardware:
649 if (event->pmu->enable(event)) {
650 event->state = PERF_EVENT_STATE_INACTIVE;
655 event->tstamp_running += ctx->time - event->tstamp_stopped;
657 if (!is_software_event(event))
658 cpuctx->active_oncpu++;
661 if (event->attr.exclusive)
662 cpuctx->exclusive = 1;
668 group_sched_in(struct perf_event *group_event,
669 struct perf_cpu_context *cpuctx,
670 struct perf_event_context *ctx,
673 struct perf_event *event, *partial_group;
676 if (group_event->state == PERF_EVENT_STATE_OFF)
679 ret = hw_perf_group_sched_in(group_event, cpuctx, ctx, cpu);
681 return ret < 0 ? ret : 0;
683 if (event_sched_in(group_event, cpuctx, ctx, cpu))
687 * Schedule in siblings as one group (if any):
689 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
690 if (event_sched_in(event, cpuctx, ctx, cpu)) {
691 partial_group = event;
700 * Groups can be scheduled in as one unit only, so undo any
701 * partial group before returning:
703 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
704 if (event == partial_group)
706 event_sched_out(event, cpuctx, ctx);
708 event_sched_out(group_event, cpuctx, ctx);
714 * Work out whether we can put this event group on the CPU now.
716 static int group_can_go_on(struct perf_event *event,
717 struct perf_cpu_context *cpuctx,
721 * Groups consisting entirely of software events can always go on.
723 if (event->group_flags & PERF_GROUP_SOFTWARE)
726 * If an exclusive group is already on, no other hardware
729 if (cpuctx->exclusive)
732 * If this group is exclusive and there are already
733 * events on the CPU, it can't go on.
735 if (event->attr.exclusive && cpuctx->active_oncpu)
738 * Otherwise, try to add it if all previous groups were able
744 static void add_event_to_ctx(struct perf_event *event,
745 struct perf_event_context *ctx)
747 list_add_event(event, ctx);
748 event->tstamp_enabled = ctx->time;
749 event->tstamp_running = ctx->time;
750 event->tstamp_stopped = ctx->time;
754 * Cross CPU call to install and enable a performance event
756 * Must be called with ctx->mutex held
758 static void __perf_install_in_context(void *info)
760 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
761 struct perf_event *event = info;
762 struct perf_event_context *ctx = event->ctx;
763 struct perf_event *leader = event->group_leader;
764 int cpu = smp_processor_id();
768 * If this is a task context, we need to check whether it is
769 * the current task context of this cpu. If not it has been
770 * scheduled out before the smp call arrived.
771 * Or possibly this is the right context but it isn't
772 * on this cpu because it had no events.
774 if (ctx->task && cpuctx->task_ctx != ctx) {
775 if (cpuctx->task_ctx || ctx->task != current)
777 cpuctx->task_ctx = ctx;
780 raw_spin_lock(&ctx->lock);
782 update_context_time(ctx);
785 * Protect the list operation against NMI by disabling the
786 * events on a global level. NOP for non NMI based events.
790 add_event_to_ctx(event, ctx);
792 if (event->cpu != -1 && event->cpu != smp_processor_id())
796 * Don't put the event on if it is disabled or if
797 * it is in a group and the group isn't on.
799 if (event->state != PERF_EVENT_STATE_INACTIVE ||
800 (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
804 * An exclusive event can't go on if there are already active
805 * hardware events, and no hardware event can go on if there
806 * is already an exclusive event on.
808 if (!group_can_go_on(event, cpuctx, 1))
811 err = event_sched_in(event, cpuctx, ctx, cpu);
815 * This event couldn't go on. If it is in a group
816 * then we have to pull the whole group off.
817 * If the event group is pinned then put it in error state.
820 group_sched_out(leader, cpuctx, ctx);
821 if (leader->attr.pinned) {
822 update_group_times(leader);
823 leader->state = PERF_EVENT_STATE_ERROR;
827 if (!err && !ctx->task && cpuctx->max_pertask)
828 cpuctx->max_pertask--;
833 raw_spin_unlock(&ctx->lock);
837 * Attach a performance event to a context
839 * First we add the event to the list with the hardware enable bit
840 * in event->hw_config cleared.
842 * If the event is attached to a task which is on a CPU we use a smp
843 * call to enable it in the task context. The task might have been
844 * scheduled away, but we check this in the smp call again.
846 * Must be called with ctx->mutex held.
849 perf_install_in_context(struct perf_event_context *ctx,
850 struct perf_event *event,
853 struct task_struct *task = ctx->task;
857 * Per cpu events are installed via an smp call and
858 * the install is always successful.
860 smp_call_function_single(cpu, __perf_install_in_context,
866 task_oncpu_function_call(task, __perf_install_in_context,
869 raw_spin_lock_irq(&ctx->lock);
871 * we need to retry the smp call.
873 if (ctx->is_active && list_empty(&event->group_entry)) {
874 raw_spin_unlock_irq(&ctx->lock);
879 * The lock prevents that this context is scheduled in so we
880 * can add the event safely, if it the call above did not
883 if (list_empty(&event->group_entry))
884 add_event_to_ctx(event, ctx);
885 raw_spin_unlock_irq(&ctx->lock);
889 * Put a event into inactive state and update time fields.
890 * Enabling the leader of a group effectively enables all
891 * the group members that aren't explicitly disabled, so we
892 * have to update their ->tstamp_enabled also.
893 * Note: this works for group members as well as group leaders
894 * since the non-leader members' sibling_lists will be empty.
896 static void __perf_event_mark_enabled(struct perf_event *event,
897 struct perf_event_context *ctx)
899 struct perf_event *sub;
901 event->state = PERF_EVENT_STATE_INACTIVE;
902 event->tstamp_enabled = ctx->time - event->total_time_enabled;
903 list_for_each_entry(sub, &event->sibling_list, group_entry)
904 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
905 sub->tstamp_enabled =
906 ctx->time - sub->total_time_enabled;
910 * Cross CPU call to enable a performance event
912 static void __perf_event_enable(void *info)
914 struct perf_event *event = info;
915 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
916 struct perf_event_context *ctx = event->ctx;
917 struct perf_event *leader = event->group_leader;
921 * If this is a per-task event, need to check whether this
922 * event's task is the current task on this cpu.
924 if (ctx->task && cpuctx->task_ctx != ctx) {
925 if (cpuctx->task_ctx || ctx->task != current)
927 cpuctx->task_ctx = ctx;
930 raw_spin_lock(&ctx->lock);
932 update_context_time(ctx);
934 if (event->state >= PERF_EVENT_STATE_INACTIVE)
936 __perf_event_mark_enabled(event, ctx);
938 if (event->cpu != -1 && event->cpu != smp_processor_id())
942 * If the event is in a group and isn't the group leader,
943 * then don't put it on unless the group is on.
945 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
948 if (!group_can_go_on(event, cpuctx, 1)) {
953 err = group_sched_in(event, cpuctx, ctx,
956 err = event_sched_in(event, cpuctx, ctx,
963 * If this event can't go on and it's part of a
964 * group, then the whole group has to come off.
967 group_sched_out(leader, cpuctx, ctx);
968 if (leader->attr.pinned) {
969 update_group_times(leader);
970 leader->state = PERF_EVENT_STATE_ERROR;
975 raw_spin_unlock(&ctx->lock);
981 * If event->ctx is a cloned context, callers must make sure that
982 * every task struct that event->ctx->task could possibly point to
983 * remains valid. This condition is satisfied when called through
984 * perf_event_for_each_child or perf_event_for_each as described
985 * for perf_event_disable.
987 void perf_event_enable(struct perf_event *event)
989 struct perf_event_context *ctx = event->ctx;
990 struct task_struct *task = ctx->task;
994 * Enable the event on the cpu that it's on
996 smp_call_function_single(event->cpu, __perf_event_enable,
1001 raw_spin_lock_irq(&ctx->lock);
1002 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1006 * If the event is in error state, clear that first.
1007 * That way, if we see the event in error state below, we
1008 * know that it has gone back into error state, as distinct
1009 * from the task having been scheduled away before the
1010 * cross-call arrived.
1012 if (event->state == PERF_EVENT_STATE_ERROR)
1013 event->state = PERF_EVENT_STATE_OFF;
1016 raw_spin_unlock_irq(&ctx->lock);
1017 task_oncpu_function_call(task, __perf_event_enable, event);
1019 raw_spin_lock_irq(&ctx->lock);
1022 * If the context is active and the event is still off,
1023 * we need to retry the cross-call.
1025 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF)
1029 * Since we have the lock this context can't be scheduled
1030 * in, so we can change the state safely.
1032 if (event->state == PERF_EVENT_STATE_OFF)
1033 __perf_event_mark_enabled(event, ctx);
1036 raw_spin_unlock_irq(&ctx->lock);
1039 static int perf_event_refresh(struct perf_event *event, int refresh)
1042 * not supported on inherited events
1044 if (event->attr.inherit)
1047 atomic_add(refresh, &event->event_limit);
1048 perf_event_enable(event);
1054 EVENT_FLEXIBLE = 0x1,
1056 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
1059 static void ctx_sched_out(struct perf_event_context *ctx,
1060 struct perf_cpu_context *cpuctx,
1061 enum event_type_t event_type)
1063 struct perf_event *event;
1065 raw_spin_lock(&ctx->lock);
1067 if (likely(!ctx->nr_events))
1069 update_context_time(ctx);
1072 if (!ctx->nr_active)
1075 if (event_type & EVENT_PINNED)
1076 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
1077 group_sched_out(event, cpuctx, ctx);
1079 if (event_type & EVENT_FLEXIBLE)
1080 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
1081 group_sched_out(event, cpuctx, ctx);
1086 raw_spin_unlock(&ctx->lock);
1090 * Test whether two contexts are equivalent, i.e. whether they
1091 * have both been cloned from the same version of the same context
1092 * and they both have the same number of enabled events.
1093 * If the number of enabled events is the same, then the set
1094 * of enabled events should be the same, because these are both
1095 * inherited contexts, therefore we can't access individual events
1096 * in them directly with an fd; we can only enable/disable all
1097 * events via prctl, or enable/disable all events in a family
1098 * via ioctl, which will have the same effect on both contexts.
1100 static int context_equiv(struct perf_event_context *ctx1,
1101 struct perf_event_context *ctx2)
1103 return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
1104 && ctx1->parent_gen == ctx2->parent_gen
1105 && !ctx1->pin_count && !ctx2->pin_count;
1108 static void __perf_event_sync_stat(struct perf_event *event,
1109 struct perf_event *next_event)
1113 if (!event->attr.inherit_stat)
1117 * Update the event value, we cannot use perf_event_read()
1118 * because we're in the middle of a context switch and have IRQs
1119 * disabled, which upsets smp_call_function_single(), however
1120 * we know the event must be on the current CPU, therefore we
1121 * don't need to use it.
1123 switch (event->state) {
1124 case PERF_EVENT_STATE_ACTIVE:
1125 event->pmu->read(event);
1128 case PERF_EVENT_STATE_INACTIVE:
1129 update_event_times(event);
1137 * In order to keep per-task stats reliable we need to flip the event
1138 * values when we flip the contexts.
1140 value = atomic64_read(&next_event->count);
1141 value = atomic64_xchg(&event->count, value);
1142 atomic64_set(&next_event->count, value);
1144 swap(event->total_time_enabled, next_event->total_time_enabled);
1145 swap(event->total_time_running, next_event->total_time_running);
1148 * Since we swizzled the values, update the user visible data too.
1150 perf_event_update_userpage(event);
1151 perf_event_update_userpage(next_event);
1154 #define list_next_entry(pos, member) \
1155 list_entry(pos->member.next, typeof(*pos), member)
1157 static void perf_event_sync_stat(struct perf_event_context *ctx,
1158 struct perf_event_context *next_ctx)
1160 struct perf_event *event, *next_event;
1165 update_context_time(ctx);
1167 event = list_first_entry(&ctx->event_list,
1168 struct perf_event, event_entry);
1170 next_event = list_first_entry(&next_ctx->event_list,
1171 struct perf_event, event_entry);
1173 while (&event->event_entry != &ctx->event_list &&
1174 &next_event->event_entry != &next_ctx->event_list) {
1176 __perf_event_sync_stat(event, next_event);
1178 event = list_next_entry(event, event_entry);
1179 next_event = list_next_entry(next_event, event_entry);
1184 * Called from scheduler to remove the events of the current task,
1185 * with interrupts disabled.
1187 * We stop each event and update the event value in event->count.
1189 * This does not protect us against NMI, but disable()
1190 * sets the disabled bit in the control field of event _before_
1191 * accessing the event control register. If a NMI hits, then it will
1192 * not restart the event.
1194 void perf_event_task_sched_out(struct task_struct *task,
1195 struct task_struct *next)
1197 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1198 struct perf_event_context *ctx = task->perf_event_ctxp;
1199 struct perf_event_context *next_ctx;
1200 struct perf_event_context *parent;
1201 struct pt_regs *regs;
1204 regs = task_pt_regs(task);
1205 perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, regs, 0);
1207 if (likely(!ctx || !cpuctx->task_ctx))
1211 parent = rcu_dereference(ctx->parent_ctx);
1212 next_ctx = next->perf_event_ctxp;
1213 if (parent && next_ctx &&
1214 rcu_dereference(next_ctx->parent_ctx) == parent) {
1216 * Looks like the two contexts are clones, so we might be
1217 * able to optimize the context switch. We lock both
1218 * contexts and check that they are clones under the
1219 * lock (including re-checking that neither has been
1220 * uncloned in the meantime). It doesn't matter which
1221 * order we take the locks because no other cpu could
1222 * be trying to lock both of these tasks.
1224 raw_spin_lock(&ctx->lock);
1225 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
1226 if (context_equiv(ctx, next_ctx)) {
1228 * XXX do we need a memory barrier of sorts
1229 * wrt to rcu_dereference() of perf_event_ctxp
1231 task->perf_event_ctxp = next_ctx;
1232 next->perf_event_ctxp = ctx;
1234 next_ctx->task = task;
1237 perf_event_sync_stat(ctx, next_ctx);
1239 raw_spin_unlock(&next_ctx->lock);
1240 raw_spin_unlock(&ctx->lock);
1245 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
1246 cpuctx->task_ctx = NULL;
1250 static void task_ctx_sched_out(struct perf_event_context *ctx,
1251 enum event_type_t event_type)
1253 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1255 if (!cpuctx->task_ctx)
1258 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
1261 ctx_sched_out(ctx, cpuctx, event_type);
1262 cpuctx->task_ctx = NULL;
1266 * Called with IRQs disabled
1268 static void __perf_event_task_sched_out(struct perf_event_context *ctx)
1270 task_ctx_sched_out(ctx, EVENT_ALL);
1274 * Called with IRQs disabled
1276 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
1277 enum event_type_t event_type)
1279 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
1283 ctx_pinned_sched_in(struct perf_event_context *ctx,
1284 struct perf_cpu_context *cpuctx,
1287 struct perf_event *event;
1289 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1290 if (event->state <= PERF_EVENT_STATE_OFF)
1292 if (event->cpu != -1 && event->cpu != cpu)
1295 if (group_can_go_on(event, cpuctx, 1))
1296 group_sched_in(event, cpuctx, ctx, cpu);
1299 * If this pinned group hasn't been scheduled,
1300 * put it in error state.
1302 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1303 update_group_times(event);
1304 event->state = PERF_EVENT_STATE_ERROR;
1310 ctx_flexible_sched_in(struct perf_event_context *ctx,
1311 struct perf_cpu_context *cpuctx,
1314 struct perf_event *event;
1317 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1318 /* Ignore events in OFF or ERROR state */
1319 if (event->state <= PERF_EVENT_STATE_OFF)
1322 * Listen to the 'cpu' scheduling filter constraint
1325 if (event->cpu != -1 && event->cpu != cpu)
1328 if (group_can_go_on(event, cpuctx, can_add_hw))
1329 if (group_sched_in(event, cpuctx, ctx, cpu))
1335 ctx_sched_in(struct perf_event_context *ctx,
1336 struct perf_cpu_context *cpuctx,
1337 enum event_type_t event_type)
1339 int cpu = smp_processor_id();
1341 raw_spin_lock(&ctx->lock);
1343 if (likely(!ctx->nr_events))
1346 ctx->timestamp = perf_clock();
1351 * First go through the list and put on any pinned groups
1352 * in order to give them the best chance of going on.
1354 if (event_type & EVENT_PINNED)
1355 ctx_pinned_sched_in(ctx, cpuctx, cpu);
1357 /* Then walk through the lower prio flexible groups */
1358 if (event_type & EVENT_FLEXIBLE)
1359 ctx_flexible_sched_in(ctx, cpuctx, cpu);
1363 raw_spin_unlock(&ctx->lock);
1366 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
1367 enum event_type_t event_type)
1369 struct perf_event_context *ctx = &cpuctx->ctx;
1371 ctx_sched_in(ctx, cpuctx, event_type);
1374 static void task_ctx_sched_in(struct task_struct *task,
1375 enum event_type_t event_type)
1377 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1378 struct perf_event_context *ctx = task->perf_event_ctxp;
1382 if (cpuctx->task_ctx == ctx)
1384 ctx_sched_in(ctx, cpuctx, event_type);
1385 cpuctx->task_ctx = ctx;
1388 * Called from scheduler to add the events of the current task
1389 * with interrupts disabled.
1391 * We restore the event value and then enable it.
1393 * This does not protect us against NMI, but enable()
1394 * sets the enabled bit in the control field of event _before_
1395 * accessing the event control register. If a NMI hits, then it will
1396 * keep the event running.
1398 void perf_event_task_sched_in(struct task_struct *task)
1400 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1401 struct perf_event_context *ctx = task->perf_event_ctxp;
1406 if (cpuctx->task_ctx == ctx)
1410 * We want to keep the following priority order:
1411 * cpu pinned (that don't need to move), task pinned,
1412 * cpu flexible, task flexible.
1414 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1416 ctx_sched_in(ctx, cpuctx, EVENT_PINNED);
1417 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1418 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE);
1420 cpuctx->task_ctx = ctx;
1423 #define MAX_INTERRUPTS (~0ULL)
1425 static void perf_log_throttle(struct perf_event *event, int enable);
1427 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
1429 u64 frequency = event->attr.sample_freq;
1430 u64 sec = NSEC_PER_SEC;
1431 u64 divisor, dividend;
1433 int count_fls, nsec_fls, frequency_fls, sec_fls;
1435 count_fls = fls64(count);
1436 nsec_fls = fls64(nsec);
1437 frequency_fls = fls64(frequency);
1441 * We got @count in @nsec, with a target of sample_freq HZ
1442 * the target period becomes:
1445 * period = -------------------
1446 * @nsec * sample_freq
1451 * Reduce accuracy by one bit such that @a and @b converge
1452 * to a similar magnitude.
1454 #define REDUCE_FLS(a, b) \
1456 if (a##_fls > b##_fls) { \
1466 * Reduce accuracy until either term fits in a u64, then proceed with
1467 * the other, so that finally we can do a u64/u64 division.
1469 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
1470 REDUCE_FLS(nsec, frequency);
1471 REDUCE_FLS(sec, count);
1474 if (count_fls + sec_fls > 64) {
1475 divisor = nsec * frequency;
1477 while (count_fls + sec_fls > 64) {
1478 REDUCE_FLS(count, sec);
1482 dividend = count * sec;
1484 dividend = count * sec;
1486 while (nsec_fls + frequency_fls > 64) {
1487 REDUCE_FLS(nsec, frequency);
1491 divisor = nsec * frequency;
1494 return div64_u64(dividend, divisor);
1497 static void perf_event_stop(struct perf_event *event)
1499 if (!event->pmu->stop)
1500 return event->pmu->disable(event);
1502 return event->pmu->stop(event);
1505 static int perf_event_start(struct perf_event *event)
1507 if (!event->pmu->start)
1508 return event->pmu->enable(event);
1510 return event->pmu->start(event);
1513 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
1515 struct hw_perf_event *hwc = &event->hw;
1516 u64 period, sample_period;
1519 period = perf_calculate_period(event, nsec, count);
1521 delta = (s64)(period - hwc->sample_period);
1522 delta = (delta + 7) / 8; /* low pass filter */
1524 sample_period = hwc->sample_period + delta;
1529 hwc->sample_period = sample_period;
1531 if (atomic64_read(&hwc->period_left) > 8*sample_period) {
1533 perf_event_stop(event);
1534 atomic64_set(&hwc->period_left, 0);
1535 perf_event_start(event);
1540 static void perf_ctx_adjust_freq(struct perf_event_context *ctx)
1542 struct perf_event *event;
1543 struct hw_perf_event *hwc;
1544 u64 interrupts, now;
1547 raw_spin_lock(&ctx->lock);
1548 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
1549 if (event->state != PERF_EVENT_STATE_ACTIVE)
1552 if (event->cpu != -1 && event->cpu != smp_processor_id())
1557 interrupts = hwc->interrupts;
1558 hwc->interrupts = 0;
1561 * unthrottle events on the tick
1563 if (interrupts == MAX_INTERRUPTS) {
1564 perf_log_throttle(event, 1);
1565 event->pmu->unthrottle(event);
1568 if (!event->attr.freq || !event->attr.sample_freq)
1571 event->pmu->read(event);
1572 now = atomic64_read(&event->count);
1573 delta = now - hwc->freq_count_stamp;
1574 hwc->freq_count_stamp = now;
1577 perf_adjust_period(event, TICK_NSEC, delta);
1579 raw_spin_unlock(&ctx->lock);
1583 * Round-robin a context's events:
1585 static void rotate_ctx(struct perf_event_context *ctx)
1587 if (!ctx->nr_events)
1590 raw_spin_lock(&ctx->lock);
1592 /* Rotate the first entry last of non-pinned groups */
1593 list_rotate_left(&ctx->flexible_groups);
1595 raw_spin_unlock(&ctx->lock);
1598 void perf_event_task_tick(struct task_struct *curr)
1600 struct perf_cpu_context *cpuctx;
1601 struct perf_event_context *ctx;
1603 if (!atomic_read(&nr_events))
1606 cpuctx = &__get_cpu_var(perf_cpu_context);
1607 ctx = curr->perf_event_ctxp;
1611 perf_ctx_adjust_freq(&cpuctx->ctx);
1613 perf_ctx_adjust_freq(ctx);
1615 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1617 task_ctx_sched_out(ctx, EVENT_FLEXIBLE);
1619 rotate_ctx(&cpuctx->ctx);
1623 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1625 task_ctx_sched_in(curr, EVENT_FLEXIBLE);
1630 static int event_enable_on_exec(struct perf_event *event,
1631 struct perf_event_context *ctx)
1633 if (!event->attr.enable_on_exec)
1636 event->attr.enable_on_exec = 0;
1637 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1640 __perf_event_mark_enabled(event, ctx);
1646 * Enable all of a task's events that have been marked enable-on-exec.
1647 * This expects task == current.
1649 static void perf_event_enable_on_exec(struct task_struct *task)
1651 struct perf_event_context *ctx;
1652 struct perf_event *event;
1653 unsigned long flags;
1657 local_irq_save(flags);
1658 ctx = task->perf_event_ctxp;
1659 if (!ctx || !ctx->nr_events)
1662 __perf_event_task_sched_out(ctx);
1664 raw_spin_lock(&ctx->lock);
1666 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1667 ret = event_enable_on_exec(event, ctx);
1672 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1673 ret = event_enable_on_exec(event, ctx);
1679 * Unclone this context if we enabled any event.
1684 raw_spin_unlock(&ctx->lock);
1686 perf_event_task_sched_in(task);
1688 local_irq_restore(flags);
1692 * Cross CPU call to read the hardware event
1694 static void __perf_event_read(void *info)
1696 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1697 struct perf_event *event = info;
1698 struct perf_event_context *ctx = event->ctx;
1701 * If this is a task context, we need to check whether it is
1702 * the current task context of this cpu. If not it has been
1703 * scheduled out before the smp call arrived. In that case
1704 * event->count would have been updated to a recent sample
1705 * when the event was scheduled out.
1707 if (ctx->task && cpuctx->task_ctx != ctx)
1710 raw_spin_lock(&ctx->lock);
1711 update_context_time(ctx);
1712 update_event_times(event);
1713 raw_spin_unlock(&ctx->lock);
1715 event->pmu->read(event);
1718 static u64 perf_event_read(struct perf_event *event)
1721 * If event is enabled and currently active on a CPU, update the
1722 * value in the event structure:
1724 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1725 smp_call_function_single(event->oncpu,
1726 __perf_event_read, event, 1);
1727 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
1728 struct perf_event_context *ctx = event->ctx;
1729 unsigned long flags;
1731 raw_spin_lock_irqsave(&ctx->lock, flags);
1732 update_context_time(ctx);
1733 update_event_times(event);
1734 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1737 return atomic64_read(&event->count);
1741 * Initialize the perf_event context in a task_struct:
1744 __perf_event_init_context(struct perf_event_context *ctx,
1745 struct task_struct *task)
1747 raw_spin_lock_init(&ctx->lock);
1748 mutex_init(&ctx->mutex);
1749 INIT_LIST_HEAD(&ctx->pinned_groups);
1750 INIT_LIST_HEAD(&ctx->flexible_groups);
1751 INIT_LIST_HEAD(&ctx->event_list);
1752 atomic_set(&ctx->refcount, 1);
1756 static struct perf_event_context *find_get_context(pid_t pid, int cpu)
1758 struct perf_event_context *ctx;
1759 struct perf_cpu_context *cpuctx;
1760 struct task_struct *task;
1761 unsigned long flags;
1764 if (pid == -1 && cpu != -1) {
1765 /* Must be root to operate on a CPU event: */
1766 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
1767 return ERR_PTR(-EACCES);
1769 if (cpu < 0 || cpu >= nr_cpumask_bits)
1770 return ERR_PTR(-EINVAL);
1773 * We could be clever and allow to attach a event to an
1774 * offline CPU and activate it when the CPU comes up, but
1777 if (!cpu_online(cpu))
1778 return ERR_PTR(-ENODEV);
1780 cpuctx = &per_cpu(perf_cpu_context, cpu);
1791 task = find_task_by_vpid(pid);
1793 get_task_struct(task);
1797 return ERR_PTR(-ESRCH);
1800 * Can't attach events to a dying task.
1803 if (task->flags & PF_EXITING)
1806 /* Reuse ptrace permission checks for now. */
1808 if (!ptrace_may_access(task, PTRACE_MODE_READ))
1812 ctx = perf_lock_task_context(task, &flags);
1815 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1819 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
1823 __perf_event_init_context(ctx, task);
1825 if (cmpxchg(&task->perf_event_ctxp, NULL, ctx)) {
1827 * We raced with some other task; use
1828 * the context they set.
1833 get_task_struct(task);
1836 put_task_struct(task);
1840 put_task_struct(task);
1841 return ERR_PTR(err);
1844 static void perf_event_free_filter(struct perf_event *event);
1846 static void free_event_rcu(struct rcu_head *head)
1848 struct perf_event *event;
1850 event = container_of(head, struct perf_event, rcu_head);
1852 put_pid_ns(event->ns);
1853 perf_event_free_filter(event);
1857 static void perf_pending_sync(struct perf_event *event);
1859 static void free_event(struct perf_event *event)
1861 perf_pending_sync(event);
1863 if (!event->parent) {
1864 atomic_dec(&nr_events);
1865 if (event->attr.mmap)
1866 atomic_dec(&nr_mmap_events);
1867 if (event->attr.comm)
1868 atomic_dec(&nr_comm_events);
1869 if (event->attr.task)
1870 atomic_dec(&nr_task_events);
1873 if (event->output) {
1874 fput(event->output->filp);
1875 event->output = NULL;
1879 event->destroy(event);
1881 put_ctx(event->ctx);
1882 call_rcu(&event->rcu_head, free_event_rcu);
1885 int perf_event_release_kernel(struct perf_event *event)
1887 struct perf_event_context *ctx = event->ctx;
1889 WARN_ON_ONCE(ctx->parent_ctx);
1890 mutex_lock(&ctx->mutex);
1891 perf_event_remove_from_context(event);
1892 mutex_unlock(&ctx->mutex);
1894 mutex_lock(&event->owner->perf_event_mutex);
1895 list_del_init(&event->owner_entry);
1896 mutex_unlock(&event->owner->perf_event_mutex);
1897 put_task_struct(event->owner);
1903 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
1906 * Called when the last reference to the file is gone.
1908 static int perf_release(struct inode *inode, struct file *file)
1910 struct perf_event *event = file->private_data;
1912 file->private_data = NULL;
1914 return perf_event_release_kernel(event);
1917 static int perf_event_read_size(struct perf_event *event)
1919 int entry = sizeof(u64); /* value */
1923 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1924 size += sizeof(u64);
1926 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1927 size += sizeof(u64);
1929 if (event->attr.read_format & PERF_FORMAT_ID)
1930 entry += sizeof(u64);
1932 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1933 nr += event->group_leader->nr_siblings;
1934 size += sizeof(u64);
1942 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
1944 struct perf_event *child;
1950 mutex_lock(&event->child_mutex);
1951 total += perf_event_read(event);
1952 *enabled += event->total_time_enabled +
1953 atomic64_read(&event->child_total_time_enabled);
1954 *running += event->total_time_running +
1955 atomic64_read(&event->child_total_time_running);
1957 list_for_each_entry(child, &event->child_list, child_list) {
1958 total += perf_event_read(child);
1959 *enabled += child->total_time_enabled;
1960 *running += child->total_time_running;
1962 mutex_unlock(&event->child_mutex);
1966 EXPORT_SYMBOL_GPL(perf_event_read_value);
1968 static int perf_event_read_group(struct perf_event *event,
1969 u64 read_format, char __user *buf)
1971 struct perf_event *leader = event->group_leader, *sub;
1972 int n = 0, size = 0, ret = -EFAULT;
1973 struct perf_event_context *ctx = leader->ctx;
1975 u64 count, enabled, running;
1977 mutex_lock(&ctx->mutex);
1978 count = perf_event_read_value(leader, &enabled, &running);
1980 values[n++] = 1 + leader->nr_siblings;
1981 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1982 values[n++] = enabled;
1983 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1984 values[n++] = running;
1985 values[n++] = count;
1986 if (read_format & PERF_FORMAT_ID)
1987 values[n++] = primary_event_id(leader);
1989 size = n * sizeof(u64);
1991 if (copy_to_user(buf, values, size))
1996 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
1999 values[n++] = perf_event_read_value(sub, &enabled, &running);
2000 if (read_format & PERF_FORMAT_ID)
2001 values[n++] = primary_event_id(sub);
2003 size = n * sizeof(u64);
2005 if (copy_to_user(buf + ret, values, size)) {
2013 mutex_unlock(&ctx->mutex);
2018 static int perf_event_read_one(struct perf_event *event,
2019 u64 read_format, char __user *buf)
2021 u64 enabled, running;
2025 values[n++] = perf_event_read_value(event, &enabled, &running);
2026 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2027 values[n++] = enabled;
2028 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2029 values[n++] = running;
2030 if (read_format & PERF_FORMAT_ID)
2031 values[n++] = primary_event_id(event);
2033 if (copy_to_user(buf, values, n * sizeof(u64)))
2036 return n * sizeof(u64);
2040 * Read the performance event - simple non blocking version for now
2043 perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
2045 u64 read_format = event->attr.read_format;
2049 * Return end-of-file for a read on a event that is in
2050 * error state (i.e. because it was pinned but it couldn't be
2051 * scheduled on to the CPU at some point).
2053 if (event->state == PERF_EVENT_STATE_ERROR)
2056 if (count < perf_event_read_size(event))
2059 WARN_ON_ONCE(event->ctx->parent_ctx);
2060 if (read_format & PERF_FORMAT_GROUP)
2061 ret = perf_event_read_group(event, read_format, buf);
2063 ret = perf_event_read_one(event, read_format, buf);
2069 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
2071 struct perf_event *event = file->private_data;
2073 return perf_read_hw(event, buf, count);
2076 static unsigned int perf_poll(struct file *file, poll_table *wait)
2078 struct perf_event *event = file->private_data;
2079 struct perf_mmap_data *data;
2080 unsigned int events = POLL_HUP;
2083 data = rcu_dereference(event->data);
2085 events = atomic_xchg(&data->poll, 0);
2088 poll_wait(file, &event->waitq, wait);
2093 static void perf_event_reset(struct perf_event *event)
2095 (void)perf_event_read(event);
2096 atomic64_set(&event->count, 0);
2097 perf_event_update_userpage(event);
2101 * Holding the top-level event's child_mutex means that any
2102 * descendant process that has inherited this event will block
2103 * in sync_child_event if it goes to exit, thus satisfying the
2104 * task existence requirements of perf_event_enable/disable.
2106 static void perf_event_for_each_child(struct perf_event *event,
2107 void (*func)(struct perf_event *))
2109 struct perf_event *child;
2111 WARN_ON_ONCE(event->ctx->parent_ctx);
2112 mutex_lock(&event->child_mutex);
2114 list_for_each_entry(child, &event->child_list, child_list)
2116 mutex_unlock(&event->child_mutex);
2119 static void perf_event_for_each(struct perf_event *event,
2120 void (*func)(struct perf_event *))
2122 struct perf_event_context *ctx = event->ctx;
2123 struct perf_event *sibling;
2125 WARN_ON_ONCE(ctx->parent_ctx);
2126 mutex_lock(&ctx->mutex);
2127 event = event->group_leader;
2129 perf_event_for_each_child(event, func);
2131 list_for_each_entry(sibling, &event->sibling_list, group_entry)
2132 perf_event_for_each_child(event, func);
2133 mutex_unlock(&ctx->mutex);
2136 static int perf_event_period(struct perf_event *event, u64 __user *arg)
2138 struct perf_event_context *ctx = event->ctx;
2143 if (!event->attr.sample_period)
2146 size = copy_from_user(&value, arg, sizeof(value));
2147 if (size != sizeof(value))
2153 raw_spin_lock_irq(&ctx->lock);
2154 if (event->attr.freq) {
2155 if (value > sysctl_perf_event_sample_rate) {
2160 event->attr.sample_freq = value;
2162 event->attr.sample_period = value;
2163 event->hw.sample_period = value;
2166 raw_spin_unlock_irq(&ctx->lock);
2171 static int perf_event_set_output(struct perf_event *event, int output_fd);
2172 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
2174 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2176 struct perf_event *event = file->private_data;
2177 void (*func)(struct perf_event *);
2181 case PERF_EVENT_IOC_ENABLE:
2182 func = perf_event_enable;
2184 case PERF_EVENT_IOC_DISABLE:
2185 func = perf_event_disable;
2187 case PERF_EVENT_IOC_RESET:
2188 func = perf_event_reset;
2191 case PERF_EVENT_IOC_REFRESH:
2192 return perf_event_refresh(event, arg);
2194 case PERF_EVENT_IOC_PERIOD:
2195 return perf_event_period(event, (u64 __user *)arg);
2197 case PERF_EVENT_IOC_SET_OUTPUT:
2198 return perf_event_set_output(event, arg);
2200 case PERF_EVENT_IOC_SET_FILTER:
2201 return perf_event_set_filter(event, (void __user *)arg);
2207 if (flags & PERF_IOC_FLAG_GROUP)
2208 perf_event_for_each(event, func);
2210 perf_event_for_each_child(event, func);
2215 int perf_event_task_enable(void)
2217 struct perf_event *event;
2219 mutex_lock(¤t->perf_event_mutex);
2220 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
2221 perf_event_for_each_child(event, perf_event_enable);
2222 mutex_unlock(¤t->perf_event_mutex);
2227 int perf_event_task_disable(void)
2229 struct perf_event *event;
2231 mutex_lock(¤t->perf_event_mutex);
2232 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
2233 perf_event_for_each_child(event, perf_event_disable);
2234 mutex_unlock(¤t->perf_event_mutex);
2239 #ifndef PERF_EVENT_INDEX_OFFSET
2240 # define PERF_EVENT_INDEX_OFFSET 0
2243 static int perf_event_index(struct perf_event *event)
2245 if (event->state != PERF_EVENT_STATE_ACTIVE)
2248 return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
2252 * Callers need to ensure there can be no nesting of this function, otherwise
2253 * the seqlock logic goes bad. We can not serialize this because the arch
2254 * code calls this from NMI context.
2256 void perf_event_update_userpage(struct perf_event *event)
2258 struct perf_event_mmap_page *userpg;
2259 struct perf_mmap_data *data;
2262 data = rcu_dereference(event->data);
2266 userpg = data->user_page;
2269 * Disable preemption so as to not let the corresponding user-space
2270 * spin too long if we get preempted.
2275 userpg->index = perf_event_index(event);
2276 userpg->offset = atomic64_read(&event->count);
2277 if (event->state == PERF_EVENT_STATE_ACTIVE)
2278 userpg->offset -= atomic64_read(&event->hw.prev_count);
2280 userpg->time_enabled = event->total_time_enabled +
2281 atomic64_read(&event->child_total_time_enabled);
2283 userpg->time_running = event->total_time_running +
2284 atomic64_read(&event->child_total_time_running);
2293 static unsigned long perf_data_size(struct perf_mmap_data *data)
2295 return data->nr_pages << (PAGE_SHIFT + data->data_order);
2298 #ifndef CONFIG_PERF_USE_VMALLOC
2301 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2304 static struct page *
2305 perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
2307 if (pgoff > data->nr_pages)
2311 return virt_to_page(data->user_page);
2313 return virt_to_page(data->data_pages[pgoff - 1]);
2316 static struct perf_mmap_data *
2317 perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
2319 struct perf_mmap_data *data;
2323 WARN_ON(atomic_read(&event->mmap_count));
2325 size = sizeof(struct perf_mmap_data);
2326 size += nr_pages * sizeof(void *);
2328 data = kzalloc(size, GFP_KERNEL);
2332 data->user_page = (void *)get_zeroed_page(GFP_KERNEL);
2333 if (!data->user_page)
2334 goto fail_user_page;
2336 for (i = 0; i < nr_pages; i++) {
2337 data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
2338 if (!data->data_pages[i])
2339 goto fail_data_pages;
2342 data->data_order = 0;
2343 data->nr_pages = nr_pages;
2348 for (i--; i >= 0; i--)
2349 free_page((unsigned long)data->data_pages[i]);
2351 free_page((unsigned long)data->user_page);
2360 static void perf_mmap_free_page(unsigned long addr)
2362 struct page *page = virt_to_page((void *)addr);
2364 page->mapping = NULL;
2368 static void perf_mmap_data_free(struct perf_mmap_data *data)
2372 perf_mmap_free_page((unsigned long)data->user_page);
2373 for (i = 0; i < data->nr_pages; i++)
2374 perf_mmap_free_page((unsigned long)data->data_pages[i]);
2381 * Back perf_mmap() with vmalloc memory.
2383 * Required for architectures that have d-cache aliasing issues.
2386 static struct page *
2387 perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
2389 if (pgoff > (1UL << data->data_order))
2392 return vmalloc_to_page((void *)data->user_page + pgoff * PAGE_SIZE);
2395 static void perf_mmap_unmark_page(void *addr)
2397 struct page *page = vmalloc_to_page(addr);
2399 page->mapping = NULL;
2402 static void perf_mmap_data_free_work(struct work_struct *work)
2404 struct perf_mmap_data *data;
2408 data = container_of(work, struct perf_mmap_data, work);
2409 nr = 1 << data->data_order;
2411 base = data->user_page;
2412 for (i = 0; i < nr + 1; i++)
2413 perf_mmap_unmark_page(base + (i * PAGE_SIZE));
2419 static void perf_mmap_data_free(struct perf_mmap_data *data)
2421 schedule_work(&data->work);
2424 static struct perf_mmap_data *
2425 perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
2427 struct perf_mmap_data *data;
2431 WARN_ON(atomic_read(&event->mmap_count));
2433 size = sizeof(struct perf_mmap_data);
2434 size += sizeof(void *);
2436 data = kzalloc(size, GFP_KERNEL);
2440 INIT_WORK(&data->work, perf_mmap_data_free_work);
2442 all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
2446 data->user_page = all_buf;
2447 data->data_pages[0] = all_buf + PAGE_SIZE;
2448 data->data_order = ilog2(nr_pages);
2462 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2464 struct perf_event *event = vma->vm_file->private_data;
2465 struct perf_mmap_data *data;
2466 int ret = VM_FAULT_SIGBUS;
2468 if (vmf->flags & FAULT_FLAG_MKWRITE) {
2469 if (vmf->pgoff == 0)
2475 data = rcu_dereference(event->data);
2479 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
2482 vmf->page = perf_mmap_to_page(data, vmf->pgoff);
2486 get_page(vmf->page);
2487 vmf->page->mapping = vma->vm_file->f_mapping;
2488 vmf->page->index = vmf->pgoff;
2498 perf_mmap_data_init(struct perf_event *event, struct perf_mmap_data *data)
2500 long max_size = perf_data_size(data);
2502 atomic_set(&data->lock, -1);
2504 if (event->attr.watermark) {
2505 data->watermark = min_t(long, max_size,
2506 event->attr.wakeup_watermark);
2509 if (!data->watermark)
2510 data->watermark = max_size / 2;
2513 rcu_assign_pointer(event->data, data);
2516 static void perf_mmap_data_free_rcu(struct rcu_head *rcu_head)
2518 struct perf_mmap_data *data;
2520 data = container_of(rcu_head, struct perf_mmap_data, rcu_head);
2521 perf_mmap_data_free(data);
2524 static void perf_mmap_data_release(struct perf_event *event)
2526 struct perf_mmap_data *data = event->data;
2528 WARN_ON(atomic_read(&event->mmap_count));
2530 rcu_assign_pointer(event->data, NULL);
2531 call_rcu(&data->rcu_head, perf_mmap_data_free_rcu);
2534 static void perf_mmap_open(struct vm_area_struct *vma)
2536 struct perf_event *event = vma->vm_file->private_data;
2538 atomic_inc(&event->mmap_count);
2541 static void perf_mmap_close(struct vm_area_struct *vma)
2543 struct perf_event *event = vma->vm_file->private_data;
2545 WARN_ON_ONCE(event->ctx->parent_ctx);
2546 if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
2547 unsigned long size = perf_data_size(event->data);
2548 struct user_struct *user = current_user();
2550 atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
2551 vma->vm_mm->locked_vm -= event->data->nr_locked;
2552 perf_mmap_data_release(event);
2553 mutex_unlock(&event->mmap_mutex);
2557 static const struct vm_operations_struct perf_mmap_vmops = {
2558 .open = perf_mmap_open,
2559 .close = perf_mmap_close,
2560 .fault = perf_mmap_fault,
2561 .page_mkwrite = perf_mmap_fault,
2564 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
2566 struct perf_event *event = file->private_data;
2567 unsigned long user_locked, user_lock_limit;
2568 struct user_struct *user = current_user();
2569 unsigned long locked, lock_limit;
2570 struct perf_mmap_data *data;
2571 unsigned long vma_size;
2572 unsigned long nr_pages;
2573 long user_extra, extra;
2576 if (!(vma->vm_flags & VM_SHARED))
2579 vma_size = vma->vm_end - vma->vm_start;
2580 nr_pages = (vma_size / PAGE_SIZE) - 1;
2583 * If we have data pages ensure they're a power-of-two number, so we
2584 * can do bitmasks instead of modulo.
2586 if (nr_pages != 0 && !is_power_of_2(nr_pages))
2589 if (vma_size != PAGE_SIZE * (1 + nr_pages))
2592 if (vma->vm_pgoff != 0)
2595 WARN_ON_ONCE(event->ctx->parent_ctx);
2596 mutex_lock(&event->mmap_mutex);
2597 if (event->output) {
2602 if (atomic_inc_not_zero(&event->mmap_count)) {
2603 if (nr_pages != event->data->nr_pages)
2608 user_extra = nr_pages + 1;
2609 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
2612 * Increase the limit linearly with more CPUs:
2614 user_lock_limit *= num_online_cpus();
2616 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
2619 if (user_locked > user_lock_limit)
2620 extra = user_locked - user_lock_limit;
2622 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
2623 lock_limit >>= PAGE_SHIFT;
2624 locked = vma->vm_mm->locked_vm + extra;
2626 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
2627 !capable(CAP_IPC_LOCK)) {
2632 WARN_ON(event->data);
2634 data = perf_mmap_data_alloc(event, nr_pages);
2640 perf_mmap_data_init(event, data);
2642 atomic_set(&event->mmap_count, 1);
2643 atomic_long_add(user_extra, &user->locked_vm);
2644 vma->vm_mm->locked_vm += extra;
2645 event->data->nr_locked = extra;
2646 if (vma->vm_flags & VM_WRITE)
2647 event->data->writable = 1;
2650 mutex_unlock(&event->mmap_mutex);
2652 vma->vm_flags |= VM_RESERVED;
2653 vma->vm_ops = &perf_mmap_vmops;
2658 static int perf_fasync(int fd, struct file *filp, int on)
2660 struct inode *inode = filp->f_path.dentry->d_inode;
2661 struct perf_event *event = filp->private_data;
2664 mutex_lock(&inode->i_mutex);
2665 retval = fasync_helper(fd, filp, on, &event->fasync);
2666 mutex_unlock(&inode->i_mutex);
2674 static const struct file_operations perf_fops = {
2675 .release = perf_release,
2678 .unlocked_ioctl = perf_ioctl,
2679 .compat_ioctl = perf_ioctl,
2681 .fasync = perf_fasync,
2687 * If there's data, ensure we set the poll() state and publish everything
2688 * to user-space before waking everybody up.
2691 void perf_event_wakeup(struct perf_event *event)
2693 wake_up_all(&event->waitq);
2695 if (event->pending_kill) {
2696 kill_fasync(&event->fasync, SIGIO, event->pending_kill);
2697 event->pending_kill = 0;
2704 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
2706 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
2707 * single linked list and use cmpxchg() to add entries lockless.
2710 static void perf_pending_event(struct perf_pending_entry *entry)
2712 struct perf_event *event = container_of(entry,
2713 struct perf_event, pending);
2715 if (event->pending_disable) {
2716 event->pending_disable = 0;
2717 __perf_event_disable(event);
2720 if (event->pending_wakeup) {
2721 event->pending_wakeup = 0;
2722 perf_event_wakeup(event);
2726 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
2728 static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
2732 static void perf_pending_queue(struct perf_pending_entry *entry,
2733 void (*func)(struct perf_pending_entry *))
2735 struct perf_pending_entry **head;
2737 if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
2742 head = &get_cpu_var(perf_pending_head);
2745 entry->next = *head;
2746 } while (cmpxchg(head, entry->next, entry) != entry->next);
2748 set_perf_event_pending();
2750 put_cpu_var(perf_pending_head);
2753 static int __perf_pending_run(void)
2755 struct perf_pending_entry *list;
2758 list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
2759 while (list != PENDING_TAIL) {
2760 void (*func)(struct perf_pending_entry *);
2761 struct perf_pending_entry *entry = list;
2768 * Ensure we observe the unqueue before we issue the wakeup,
2769 * so that we won't be waiting forever.
2770 * -- see perf_not_pending().
2781 static inline int perf_not_pending(struct perf_event *event)
2784 * If we flush on whatever cpu we run, there is a chance we don't
2788 __perf_pending_run();
2792 * Ensure we see the proper queue state before going to sleep
2793 * so that we do not miss the wakeup. -- see perf_pending_handle()
2796 return event->pending.next == NULL;
2799 static void perf_pending_sync(struct perf_event *event)
2801 wait_event(event->waitq, perf_not_pending(event));
2804 void perf_event_do_pending(void)
2806 __perf_pending_run();
2810 * Callchain support -- arch specific
2813 __weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
2821 static bool perf_output_space(struct perf_mmap_data *data, unsigned long tail,
2822 unsigned long offset, unsigned long head)
2826 if (!data->writable)
2829 mask = perf_data_size(data) - 1;
2831 offset = (offset - tail) & mask;
2832 head = (head - tail) & mask;
2834 if ((int)(head - offset) < 0)
2840 static void perf_output_wakeup(struct perf_output_handle *handle)
2842 atomic_set(&handle->data->poll, POLL_IN);
2845 handle->event->pending_wakeup = 1;
2846 perf_pending_queue(&handle->event->pending,
2847 perf_pending_event);
2849 perf_event_wakeup(handle->event);
2853 * Curious locking construct.
2855 * We need to ensure a later event_id doesn't publish a head when a former
2856 * event_id isn't done writing. However since we need to deal with NMIs we
2857 * cannot fully serialize things.
2859 * What we do is serialize between CPUs so we only have to deal with NMI
2860 * nesting on a single CPU.
2862 * We only publish the head (and generate a wakeup) when the outer-most
2863 * event_id completes.
2865 static void perf_output_lock(struct perf_output_handle *handle)
2867 struct perf_mmap_data *data = handle->data;
2868 int cur, cpu = get_cpu();
2873 cur = atomic_cmpxchg(&data->lock, -1, cpu);
2885 static void perf_output_unlock(struct perf_output_handle *handle)
2887 struct perf_mmap_data *data = handle->data;
2891 data->done_head = data->head;
2893 if (!handle->locked)
2898 * The xchg implies a full barrier that ensures all writes are done
2899 * before we publish the new head, matched by a rmb() in userspace when
2900 * reading this position.
2902 while ((head = atomic_long_xchg(&data->done_head, 0)))
2903 data->user_page->data_head = head;
2906 * NMI can happen here, which means we can miss a done_head update.
2909 cpu = atomic_xchg(&data->lock, -1);
2910 WARN_ON_ONCE(cpu != smp_processor_id());
2913 * Therefore we have to validate we did not indeed do so.
2915 if (unlikely(atomic_long_read(&data->done_head))) {
2917 * Since we had it locked, we can lock it again.
2919 while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
2925 if (atomic_xchg(&data->wakeup, 0))
2926 perf_output_wakeup(handle);
2931 void perf_output_copy(struct perf_output_handle *handle,
2932 const void *buf, unsigned int len)
2934 unsigned int pages_mask;
2935 unsigned long offset;
2939 offset = handle->offset;
2940 pages_mask = handle->data->nr_pages - 1;
2941 pages = handle->data->data_pages;
2944 unsigned long page_offset;
2945 unsigned long page_size;
2948 nr = (offset >> PAGE_SHIFT) & pages_mask;
2949 page_size = 1UL << (handle->data->data_order + PAGE_SHIFT);
2950 page_offset = offset & (page_size - 1);
2951 size = min_t(unsigned int, page_size - page_offset, len);
2953 memcpy(pages[nr] + page_offset, buf, size);
2960 handle->offset = offset;
2963 * Check we didn't copy past our reservation window, taking the
2964 * possible unsigned int wrap into account.
2966 WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0);
2969 int perf_output_begin(struct perf_output_handle *handle,
2970 struct perf_event *event, unsigned int size,
2971 int nmi, int sample)
2973 struct perf_event *output_event;
2974 struct perf_mmap_data *data;
2975 unsigned long tail, offset, head;
2978 struct perf_event_header header;
2985 * For inherited events we send all the output towards the parent.
2988 event = event->parent;
2990 output_event = rcu_dereference(event->output);
2992 event = output_event;
2994 data = rcu_dereference(event->data);
2998 handle->data = data;
2999 handle->event = event;
3001 handle->sample = sample;
3003 if (!data->nr_pages)
3006 have_lost = atomic_read(&data->lost);
3008 size += sizeof(lost_event);
3010 perf_output_lock(handle);
3014 * Userspace could choose to issue a mb() before updating the
3015 * tail pointer. So that all reads will be completed before the
3018 tail = ACCESS_ONCE(data->user_page->data_tail);
3020 offset = head = atomic_long_read(&data->head);
3022 if (unlikely(!perf_output_space(data, tail, offset, head)))
3024 } while (atomic_long_cmpxchg(&data->head, offset, head) != offset);
3026 handle->offset = offset;
3027 handle->head = head;
3029 if (head - tail > data->watermark)
3030 atomic_set(&data->wakeup, 1);
3033 lost_event.header.type = PERF_RECORD_LOST;
3034 lost_event.header.misc = 0;
3035 lost_event.header.size = sizeof(lost_event);
3036 lost_event.id = event->id;
3037 lost_event.lost = atomic_xchg(&data->lost, 0);
3039 perf_output_put(handle, lost_event);
3045 atomic_inc(&data->lost);
3046 perf_output_unlock(handle);
3053 void perf_output_end(struct perf_output_handle *handle)
3055 struct perf_event *event = handle->event;
3056 struct perf_mmap_data *data = handle->data;
3058 int wakeup_events = event->attr.wakeup_events;
3060 if (handle->sample && wakeup_events) {
3061 int events = atomic_inc_return(&data->events);
3062 if (events >= wakeup_events) {
3063 atomic_sub(wakeup_events, &data->events);
3064 atomic_set(&data->wakeup, 1);
3068 perf_output_unlock(handle);
3072 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
3075 * only top level events have the pid namespace they were created in
3078 event = event->parent;
3080 return task_tgid_nr_ns(p, event->ns);
3083 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
3086 * only top level events have the pid namespace they were created in
3089 event = event->parent;
3091 return task_pid_nr_ns(p, event->ns);
3094 static void perf_output_read_one(struct perf_output_handle *handle,
3095 struct perf_event *event)
3097 u64 read_format = event->attr.read_format;
3101 values[n++] = atomic64_read(&event->count);
3102 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3103 values[n++] = event->total_time_enabled +
3104 atomic64_read(&event->child_total_time_enabled);
3106 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3107 values[n++] = event->total_time_running +
3108 atomic64_read(&event->child_total_time_running);
3110 if (read_format & PERF_FORMAT_ID)
3111 values[n++] = primary_event_id(event);
3113 perf_output_copy(handle, values, n * sizeof(u64));
3117 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3119 static void perf_output_read_group(struct perf_output_handle *handle,
3120 struct perf_event *event)
3122 struct perf_event *leader = event->group_leader, *sub;
3123 u64 read_format = event->attr.read_format;
3127 values[n++] = 1 + leader->nr_siblings;
3129 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3130 values[n++] = leader->total_time_enabled;
3132 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3133 values[n++] = leader->total_time_running;
3135 if (leader != event)
3136 leader->pmu->read(leader);
3138 values[n++] = atomic64_read(&leader->count);
3139 if (read_format & PERF_FORMAT_ID)
3140 values[n++] = primary_event_id(leader);
3142 perf_output_copy(handle, values, n * sizeof(u64));
3144 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3148 sub->pmu->read(sub);
3150 values[n++] = atomic64_read(&sub->count);
3151 if (read_format & PERF_FORMAT_ID)
3152 values[n++] = primary_event_id(sub);
3154 perf_output_copy(handle, values, n * sizeof(u64));
3158 static void perf_output_read(struct perf_output_handle *handle,
3159 struct perf_event *event)
3161 if (event->attr.read_format & PERF_FORMAT_GROUP)
3162 perf_output_read_group(handle, event);
3164 perf_output_read_one(handle, event);
3167 void perf_output_sample(struct perf_output_handle *handle,
3168 struct perf_event_header *header,
3169 struct perf_sample_data *data,
3170 struct perf_event *event)
3172 u64 sample_type = data->type;
3174 perf_output_put(handle, *header);
3176 if (sample_type & PERF_SAMPLE_IP)
3177 perf_output_put(handle, data->ip);
3179 if (sample_type & PERF_SAMPLE_TID)
3180 perf_output_put(handle, data->tid_entry);
3182 if (sample_type & PERF_SAMPLE_TIME)
3183 perf_output_put(handle, data->time);
3185 if (sample_type & PERF_SAMPLE_ADDR)
3186 perf_output_put(handle, data->addr);
3188 if (sample_type & PERF_SAMPLE_ID)
3189 perf_output_put(handle, data->id);
3191 if (sample_type & PERF_SAMPLE_STREAM_ID)
3192 perf_output_put(handle, data->stream_id);
3194 if (sample_type & PERF_SAMPLE_CPU)
3195 perf_output_put(handle, data->cpu_entry);
3197 if (sample_type & PERF_SAMPLE_PERIOD)
3198 perf_output_put(handle, data->period);
3200 if (sample_type & PERF_SAMPLE_READ)
3201 perf_output_read(handle, event);
3203 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3204 if (data->callchain) {
3207 if (data->callchain)
3208 size += data->callchain->nr;
3210 size *= sizeof(u64);
3212 perf_output_copy(handle, data->callchain, size);
3215 perf_output_put(handle, nr);
3219 if (sample_type & PERF_SAMPLE_RAW) {
3221 perf_output_put(handle, data->raw->size);
3222 perf_output_copy(handle, data->raw->data,
3229 .size = sizeof(u32),
3232 perf_output_put(handle, raw);
3237 void perf_prepare_sample(struct perf_event_header *header,
3238 struct perf_sample_data *data,
3239 struct perf_event *event,
3240 struct pt_regs *regs)
3242 u64 sample_type = event->attr.sample_type;
3244 data->type = sample_type;
3246 header->type = PERF_RECORD_SAMPLE;
3247 header->size = sizeof(*header);
3250 header->misc |= perf_misc_flags(regs);
3252 if (sample_type & PERF_SAMPLE_IP) {
3253 data->ip = perf_instruction_pointer(regs);
3255 header->size += sizeof(data->ip);
3258 if (sample_type & PERF_SAMPLE_TID) {
3259 /* namespace issues */
3260 data->tid_entry.pid = perf_event_pid(event, current);
3261 data->tid_entry.tid = perf_event_tid(event, current);
3263 header->size += sizeof(data->tid_entry);
3266 if (sample_type & PERF_SAMPLE_TIME) {
3267 data->time = perf_clock();
3269 header->size += sizeof(data->time);
3272 if (sample_type & PERF_SAMPLE_ADDR)
3273 header->size += sizeof(data->addr);
3275 if (sample_type & PERF_SAMPLE_ID) {
3276 data->id = primary_event_id(event);
3278 header->size += sizeof(data->id);
3281 if (sample_type & PERF_SAMPLE_STREAM_ID) {
3282 data->stream_id = event->id;
3284 header->size += sizeof(data->stream_id);
3287 if (sample_type & PERF_SAMPLE_CPU) {
3288 data->cpu_entry.cpu = raw_smp_processor_id();
3289 data->cpu_entry.reserved = 0;
3291 header->size += sizeof(data->cpu_entry);
3294 if (sample_type & PERF_SAMPLE_PERIOD)
3295 header->size += sizeof(data->period);
3297 if (sample_type & PERF_SAMPLE_READ)
3298 header->size += perf_event_read_size(event);
3300 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3303 data->callchain = perf_callchain(regs);
3305 if (data->callchain)
3306 size += data->callchain->nr;
3308 header->size += size * sizeof(u64);
3311 if (sample_type & PERF_SAMPLE_RAW) {
3312 int size = sizeof(u32);
3315 size += data->raw->size;
3317 size += sizeof(u32);
3319 WARN_ON_ONCE(size & (sizeof(u64)-1));
3320 header->size += size;
3324 static void perf_event_output(struct perf_event *event, int nmi,
3325 struct perf_sample_data *data,
3326 struct pt_regs *regs)
3328 struct perf_output_handle handle;
3329 struct perf_event_header header;
3331 perf_prepare_sample(&header, data, event, regs);
3333 if (perf_output_begin(&handle, event, header.size, nmi, 1))
3336 perf_output_sample(&handle, &header, data, event);
3338 perf_output_end(&handle);
3345 struct perf_read_event {
3346 struct perf_event_header header;
3353 perf_event_read_event(struct perf_event *event,
3354 struct task_struct *task)
3356 struct perf_output_handle handle;
3357 struct perf_read_event read_event = {
3359 .type = PERF_RECORD_READ,
3361 .size = sizeof(read_event) + perf_event_read_size(event),
3363 .pid = perf_event_pid(event, task),
3364 .tid = perf_event_tid(event, task),
3368 ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
3372 perf_output_put(&handle, read_event);
3373 perf_output_read(&handle, event);
3375 perf_output_end(&handle);
3379 * task tracking -- fork/exit
3381 * enabled by: attr.comm | attr.mmap | attr.task
3384 struct perf_task_event {
3385 struct task_struct *task;
3386 struct perf_event_context *task_ctx;
3389 struct perf_event_header header;
3399 static void perf_event_task_output(struct perf_event *event,
3400 struct perf_task_event *task_event)
3402 struct perf_output_handle handle;
3404 struct task_struct *task = task_event->task;
3407 size = task_event->event_id.header.size;
3408 ret = perf_output_begin(&handle, event, size, 0, 0);
3413 task_event->event_id.pid = perf_event_pid(event, task);
3414 task_event->event_id.ppid = perf_event_pid(event, current);
3416 task_event->event_id.tid = perf_event_tid(event, task);
3417 task_event->event_id.ptid = perf_event_tid(event, current);
3419 task_event->event_id.time = perf_clock();
3421 perf_output_put(&handle, task_event->event_id);
3423 perf_output_end(&handle);
3426 static int perf_event_task_match(struct perf_event *event)
3428 if (event->state != PERF_EVENT_STATE_ACTIVE)
3431 if (event->cpu != -1 && event->cpu != smp_processor_id())
3434 if (event->attr.comm || event->attr.mmap || event->attr.task)
3440 static void perf_event_task_ctx(struct perf_event_context *ctx,
3441 struct perf_task_event *task_event)
3443 struct perf_event *event;
3445 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3446 if (perf_event_task_match(event))
3447 perf_event_task_output(event, task_event);
3451 static void perf_event_task_event(struct perf_task_event *task_event)
3453 struct perf_cpu_context *cpuctx;
3454 struct perf_event_context *ctx = task_event->task_ctx;
3457 cpuctx = &get_cpu_var(perf_cpu_context);
3458 perf_event_task_ctx(&cpuctx->ctx, task_event);
3460 ctx = rcu_dereference(task_event->task->perf_event_ctxp);
3462 perf_event_task_ctx(ctx, task_event);
3463 put_cpu_var(perf_cpu_context);
3467 static void perf_event_task(struct task_struct *task,
3468 struct perf_event_context *task_ctx,
3471 struct perf_task_event task_event;
3473 if (!atomic_read(&nr_comm_events) &&
3474 !atomic_read(&nr_mmap_events) &&
3475 !atomic_read(&nr_task_events))
3478 task_event = (struct perf_task_event){
3480 .task_ctx = task_ctx,
3483 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
3485 .size = sizeof(task_event.event_id),
3494 perf_event_task_event(&task_event);
3497 void perf_event_fork(struct task_struct *task)
3499 perf_event_task(task, NULL, 1);
3506 struct perf_comm_event {
3507 struct task_struct *task;
3512 struct perf_event_header header;
3519 static void perf_event_comm_output(struct perf_event *event,
3520 struct perf_comm_event *comm_event)
3522 struct perf_output_handle handle;
3523 int size = comm_event->event_id.header.size;
3524 int ret = perf_output_begin(&handle, event, size, 0, 0);
3529 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
3530 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
3532 perf_output_put(&handle, comm_event->event_id);
3533 perf_output_copy(&handle, comm_event->comm,
3534 comm_event->comm_size);
3535 perf_output_end(&handle);
3538 static int perf_event_comm_match(struct perf_event *event)
3540 if (event->state != PERF_EVENT_STATE_ACTIVE)
3543 if (event->cpu != -1 && event->cpu != smp_processor_id())
3546 if (event->attr.comm)
3552 static void perf_event_comm_ctx(struct perf_event_context *ctx,
3553 struct perf_comm_event *comm_event)
3555 struct perf_event *event;
3557 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3558 if (perf_event_comm_match(event))
3559 perf_event_comm_output(event, comm_event);
3563 static void perf_event_comm_event(struct perf_comm_event *comm_event)
3565 struct perf_cpu_context *cpuctx;
3566 struct perf_event_context *ctx;
3568 char comm[TASK_COMM_LEN];
3570 memset(comm, 0, sizeof(comm));
3571 strlcpy(comm, comm_event->task->comm, sizeof(comm));
3572 size = ALIGN(strlen(comm)+1, sizeof(u64));
3574 comm_event->comm = comm;
3575 comm_event->comm_size = size;
3577 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
3580 cpuctx = &get_cpu_var(perf_cpu_context);
3581 perf_event_comm_ctx(&cpuctx->ctx, comm_event);
3582 ctx = rcu_dereference(current->perf_event_ctxp);
3584 perf_event_comm_ctx(ctx, comm_event);
3585 put_cpu_var(perf_cpu_context);
3589 void perf_event_comm(struct task_struct *task)
3591 struct perf_comm_event comm_event;
3593 if (task->perf_event_ctxp)
3594 perf_event_enable_on_exec(task);
3596 if (!atomic_read(&nr_comm_events))
3599 comm_event = (struct perf_comm_event){
3605 .type = PERF_RECORD_COMM,
3614 perf_event_comm_event(&comm_event);
3621 struct perf_mmap_event {
3622 struct vm_area_struct *vma;
3624 const char *file_name;
3628 struct perf_event_header header;
3638 static void perf_event_mmap_output(struct perf_event *event,
3639 struct perf_mmap_event *mmap_event)
3641 struct perf_output_handle handle;
3642 int size = mmap_event->event_id.header.size;
3643 int ret = perf_output_begin(&handle, event, size, 0, 0);
3648 mmap_event->event_id.pid = perf_event_pid(event, current);
3649 mmap_event->event_id.tid = perf_event_tid(event, current);
3651 perf_output_put(&handle, mmap_event->event_id);
3652 perf_output_copy(&handle, mmap_event->file_name,
3653 mmap_event->file_size);
3654 perf_output_end(&handle);
3657 static int perf_event_mmap_match(struct perf_event *event,
3658 struct perf_mmap_event *mmap_event)
3660 if (event->state != PERF_EVENT_STATE_ACTIVE)
3663 if (event->cpu != -1 && event->cpu != smp_processor_id())
3666 if (event->attr.mmap)
3672 static void perf_event_mmap_ctx(struct perf_event_context *ctx,
3673 struct perf_mmap_event *mmap_event)
3675 struct perf_event *event;
3677 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3678 if (perf_event_mmap_match(event, mmap_event))
3679 perf_event_mmap_output(event, mmap_event);
3683 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
3685 struct perf_cpu_context *cpuctx;
3686 struct perf_event_context *ctx;
3687 struct vm_area_struct *vma = mmap_event->vma;
3688 struct file *file = vma->vm_file;
3694 memset(tmp, 0, sizeof(tmp));
3698 * d_path works from the end of the buffer backwards, so we
3699 * need to add enough zero bytes after the string to handle
3700 * the 64bit alignment we do later.
3702 buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
3704 name = strncpy(tmp, "//enomem", sizeof(tmp));
3707 name = d_path(&file->f_path, buf, PATH_MAX);
3709 name = strncpy(tmp, "//toolong", sizeof(tmp));
3713 if (arch_vma_name(mmap_event->vma)) {
3714 name = strncpy(tmp, arch_vma_name(mmap_event->vma),
3720 name = strncpy(tmp, "[vdso]", sizeof(tmp));
3724 name = strncpy(tmp, "//anon", sizeof(tmp));
3729 size = ALIGN(strlen(name)+1, sizeof(u64));
3731 mmap_event->file_name = name;
3732 mmap_event->file_size = size;
3734 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
3737 cpuctx = &get_cpu_var(perf_cpu_context);
3738 perf_event_mmap_ctx(&cpuctx->ctx, mmap_event);
3739 ctx = rcu_dereference(current->perf_event_ctxp);
3741 perf_event_mmap_ctx(ctx, mmap_event);
3742 put_cpu_var(perf_cpu_context);
3748 void __perf_event_mmap(struct vm_area_struct *vma)
3750 struct perf_mmap_event mmap_event;
3752 if (!atomic_read(&nr_mmap_events))
3755 mmap_event = (struct perf_mmap_event){
3761 .type = PERF_RECORD_MMAP,
3767 .start = vma->vm_start,
3768 .len = vma->vm_end - vma->vm_start,
3769 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
3773 perf_event_mmap_event(&mmap_event);
3777 * IRQ throttle logging
3780 static void perf_log_throttle(struct perf_event *event, int enable)
3782 struct perf_output_handle handle;
3786 struct perf_event_header header;
3790 } throttle_event = {
3792 .type = PERF_RECORD_THROTTLE,
3794 .size = sizeof(throttle_event),
3796 .time = perf_clock(),
3797 .id = primary_event_id(event),
3798 .stream_id = event->id,
3802 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
3804 ret = perf_output_begin(&handle, event, sizeof(throttle_event), 1, 0);
3808 perf_output_put(&handle, throttle_event);
3809 perf_output_end(&handle);
3813 * Generic event overflow handling, sampling.
3816 static int __perf_event_overflow(struct perf_event *event, int nmi,
3817 int throttle, struct perf_sample_data *data,
3818 struct pt_regs *regs)
3820 int events = atomic_read(&event->event_limit);
3821 struct hw_perf_event *hwc = &event->hw;
3824 throttle = (throttle && event->pmu->unthrottle != NULL);
3829 if (hwc->interrupts != MAX_INTERRUPTS) {
3831 if (HZ * hwc->interrupts >
3832 (u64)sysctl_perf_event_sample_rate) {
3833 hwc->interrupts = MAX_INTERRUPTS;
3834 perf_log_throttle(event, 0);
3839 * Keep re-disabling events even though on the previous
3840 * pass we disabled it - just in case we raced with a
3841 * sched-in and the event got enabled again:
3847 if (event->attr.freq) {
3848 u64 now = perf_clock();
3849 s64 delta = now - hwc->freq_time_stamp;
3851 hwc->freq_time_stamp = now;
3853 if (delta > 0 && delta < 2*TICK_NSEC)
3854 perf_adjust_period(event, delta, hwc->last_period);
3858 * XXX event_limit might not quite work as expected on inherited
3862 event->pending_kill = POLL_IN;
3863 if (events && atomic_dec_and_test(&event->event_limit)) {
3865 event->pending_kill = POLL_HUP;
3867 event->pending_disable = 1;
3868 perf_pending_queue(&event->pending,
3869 perf_pending_event);
3871 perf_event_disable(event);
3874 if (event->overflow_handler)
3875 event->overflow_handler(event, nmi, data, regs);
3877 perf_event_output(event, nmi, data, regs);
3882 int perf_event_overflow(struct perf_event *event, int nmi,
3883 struct perf_sample_data *data,
3884 struct pt_regs *regs)
3886 return __perf_event_overflow(event, nmi, 1, data, regs);
3890 * Generic software event infrastructure
3894 * We directly increment event->count and keep a second value in
3895 * event->hw.period_left to count intervals. This period event
3896 * is kept in the range [-sample_period, 0] so that we can use the
3900 static u64 perf_swevent_set_period(struct perf_event *event)
3902 struct hw_perf_event *hwc = &event->hw;
3903 u64 period = hwc->last_period;
3907 hwc->last_period = hwc->sample_period;
3910 old = val = atomic64_read(&hwc->period_left);
3914 nr = div64_u64(period + val, period);
3915 offset = nr * period;
3917 if (atomic64_cmpxchg(&hwc->period_left, old, val) != old)
3923 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
3924 int nmi, struct perf_sample_data *data,
3925 struct pt_regs *regs)
3927 struct hw_perf_event *hwc = &event->hw;
3930 data->period = event->hw.last_period;
3932 overflow = perf_swevent_set_period(event);
3934 if (hwc->interrupts == MAX_INTERRUPTS)
3937 for (; overflow; overflow--) {
3938 if (__perf_event_overflow(event, nmi, throttle,
3941 * We inhibit the overflow from happening when
3942 * hwc->interrupts == MAX_INTERRUPTS.
3950 static void perf_swevent_unthrottle(struct perf_event *event)
3953 * Nothing to do, we already reset hwc->interrupts.
3957 static void perf_swevent_add(struct perf_event *event, u64 nr,
3958 int nmi, struct perf_sample_data *data,
3959 struct pt_regs *regs)
3961 struct hw_perf_event *hwc = &event->hw;
3963 atomic64_add(nr, &event->count);
3968 if (!hwc->sample_period)
3971 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
3972 return perf_swevent_overflow(event, 1, nmi, data, regs);
3974 if (atomic64_add_negative(nr, &hwc->period_left))
3977 perf_swevent_overflow(event, 0, nmi, data, regs);
3980 static int perf_swevent_is_counting(struct perf_event *event)
3983 * The event is active, we're good!
3985 if (event->state == PERF_EVENT_STATE_ACTIVE)
3989 * The event is off/error, not counting.
3991 if (event->state != PERF_EVENT_STATE_INACTIVE)
3995 * The event is inactive, if the context is active
3996 * we're part of a group that didn't make it on the 'pmu',
3999 if (event->ctx->is_active)
4003 * We're inactive and the context is too, this means the
4004 * task is scheduled out, we're counting events that happen
4005 * to us, like migration events.
4010 static int perf_tp_event_match(struct perf_event *event,
4011 struct perf_sample_data *data);
4013 static int perf_exclude_event(struct perf_event *event,
4014 struct pt_regs *regs)
4017 if (event->attr.exclude_user && user_mode(regs))
4020 if (event->attr.exclude_kernel && !user_mode(regs))
4027 static int perf_swevent_match(struct perf_event *event,
4028 enum perf_type_id type,
4030 struct perf_sample_data *data,
4031 struct pt_regs *regs)
4033 if (event->cpu != -1 && event->cpu != smp_processor_id())
4036 if (!perf_swevent_is_counting(event))
4039 if (event->attr.type != type)
4042 if (event->attr.config != event_id)
4045 if (perf_exclude_event(event, regs))
4048 if (event->attr.type == PERF_TYPE_TRACEPOINT &&
4049 !perf_tp_event_match(event, data))
4055 static void perf_swevent_ctx_event(struct perf_event_context *ctx,
4056 enum perf_type_id type,
4057 u32 event_id, u64 nr, int nmi,
4058 struct perf_sample_data *data,
4059 struct pt_regs *regs)
4061 struct perf_event *event;
4063 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4064 if (perf_swevent_match(event, type, event_id, data, regs))
4065 perf_swevent_add(event, nr, nmi, data, regs);
4069 int perf_swevent_get_recursion_context(void)
4071 struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);
4078 else if (in_softirq())
4083 if (cpuctx->recursion[rctx]) {
4084 put_cpu_var(perf_cpu_context);
4088 cpuctx->recursion[rctx]++;
4093 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
4095 void perf_swevent_put_recursion_context(int rctx)
4097 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
4099 cpuctx->recursion[rctx]--;
4100 put_cpu_var(perf_cpu_context);
4102 EXPORT_SYMBOL_GPL(perf_swevent_put_recursion_context);
4104 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
4106 struct perf_sample_data *data,
4107 struct pt_regs *regs)
4109 struct perf_cpu_context *cpuctx;
4110 struct perf_event_context *ctx;
4112 cpuctx = &__get_cpu_var(perf_cpu_context);
4114 perf_swevent_ctx_event(&cpuctx->ctx, type, event_id,
4115 nr, nmi, data, regs);
4117 * doesn't really matter which of the child contexts the
4118 * events ends up in.
4120 ctx = rcu_dereference(current->perf_event_ctxp);
4122 perf_swevent_ctx_event(ctx, type, event_id, nr, nmi, data, regs);
4126 void __perf_sw_event(u32 event_id, u64 nr, int nmi,
4127 struct pt_regs *regs, u64 addr)
4129 struct perf_sample_data data;
4132 rctx = perf_swevent_get_recursion_context();
4139 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
4141 perf_swevent_put_recursion_context(rctx);
4144 static void perf_swevent_read(struct perf_event *event)
4148 static int perf_swevent_enable(struct perf_event *event)
4150 struct hw_perf_event *hwc = &event->hw;
4152 if (hwc->sample_period) {
4153 hwc->last_period = hwc->sample_period;
4154 perf_swevent_set_period(event);
4159 static void perf_swevent_disable(struct perf_event *event)
4163 static const struct pmu perf_ops_generic = {
4164 .enable = perf_swevent_enable,
4165 .disable = perf_swevent_disable,
4166 .read = perf_swevent_read,
4167 .unthrottle = perf_swevent_unthrottle,
4171 * hrtimer based swevent callback
4174 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
4176 enum hrtimer_restart ret = HRTIMER_RESTART;
4177 struct perf_sample_data data;
4178 struct pt_regs *regs;
4179 struct perf_event *event;
4182 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
4183 event->pmu->read(event);
4187 data.period = event->hw.last_period;
4188 regs = get_irq_regs();
4190 * In case we exclude kernel IPs or are somehow not in interrupt
4191 * context, provide the next best thing, the user IP.
4193 if ((event->attr.exclude_kernel || !regs) &&
4194 !event->attr.exclude_user)
4195 regs = task_pt_regs(current);
4198 if (!(event->attr.exclude_idle && current->pid == 0))
4199 if (perf_event_overflow(event, 0, &data, regs))
4200 ret = HRTIMER_NORESTART;
4203 period = max_t(u64, 10000, event->hw.sample_period);
4204 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
4209 static void perf_swevent_start_hrtimer(struct perf_event *event)
4211 struct hw_perf_event *hwc = &event->hw;
4213 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
4214 hwc->hrtimer.function = perf_swevent_hrtimer;
4215 if (hwc->sample_period) {
4218 if (hwc->remaining) {
4219 if (hwc->remaining < 0)
4222 period = hwc->remaining;
4225 period = max_t(u64, 10000, hwc->sample_period);
4227 __hrtimer_start_range_ns(&hwc->hrtimer,
4228 ns_to_ktime(period), 0,
4229 HRTIMER_MODE_REL, 0);
4233 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
4235 struct hw_perf_event *hwc = &event->hw;
4237 if (hwc->sample_period) {
4238 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
4239 hwc->remaining = ktime_to_ns(remaining);
4241 hrtimer_cancel(&hwc->hrtimer);
4246 * Software event: cpu wall time clock
4249 static void cpu_clock_perf_event_update(struct perf_event *event)
4251 int cpu = raw_smp_processor_id();
4255 now = cpu_clock(cpu);
4256 prev = atomic64_xchg(&event->hw.prev_count, now);
4257 atomic64_add(now - prev, &event->count);
4260 static int cpu_clock_perf_event_enable(struct perf_event *event)
4262 struct hw_perf_event *hwc = &event->hw;
4263 int cpu = raw_smp_processor_id();
4265 atomic64_set(&hwc->prev_count, cpu_clock(cpu));
4266 perf_swevent_start_hrtimer(event);
4271 static void cpu_clock_perf_event_disable(struct perf_event *event)
4273 perf_swevent_cancel_hrtimer(event);
4274 cpu_clock_perf_event_update(event);
4277 static void cpu_clock_perf_event_read(struct perf_event *event)
4279 cpu_clock_perf_event_update(event);
4282 static const struct pmu perf_ops_cpu_clock = {
4283 .enable = cpu_clock_perf_event_enable,
4284 .disable = cpu_clock_perf_event_disable,
4285 .read = cpu_clock_perf_event_read,
4289 * Software event: task time clock
4292 static void task_clock_perf_event_update(struct perf_event *event, u64 now)
4297 prev = atomic64_xchg(&event->hw.prev_count, now);
4299 atomic64_add(delta, &event->count);
4302 static int task_clock_perf_event_enable(struct perf_event *event)
4304 struct hw_perf_event *hwc = &event->hw;
4307 now = event->ctx->time;
4309 atomic64_set(&hwc->prev_count, now);
4311 perf_swevent_start_hrtimer(event);
4316 static void task_clock_perf_event_disable(struct perf_event *event)
4318 perf_swevent_cancel_hrtimer(event);
4319 task_clock_perf_event_update(event, event->ctx->time);
4323 static void task_clock_perf_event_read(struct perf_event *event)
4328 update_context_time(event->ctx);
4329 time = event->ctx->time;
4331 u64 now = perf_clock();
4332 u64 delta = now - event->ctx->timestamp;
4333 time = event->ctx->time + delta;
4336 task_clock_perf_event_update(event, time);
4339 static const struct pmu perf_ops_task_clock = {
4340 .enable = task_clock_perf_event_enable,
4341 .disable = task_clock_perf_event_disable,
4342 .read = task_clock_perf_event_read,
4345 #ifdef CONFIG_EVENT_TRACING
4347 void perf_tp_event(int event_id, u64 addr, u64 count, void *record,
4350 struct perf_raw_record raw = {
4355 struct perf_sample_data data = {
4360 struct pt_regs *regs = get_irq_regs();
4363 regs = task_pt_regs(current);
4365 /* Trace events already protected against recursion */
4366 do_perf_sw_event(PERF_TYPE_TRACEPOINT, event_id, count, 1,
4369 EXPORT_SYMBOL_GPL(perf_tp_event);
4371 static int perf_tp_event_match(struct perf_event *event,
4372 struct perf_sample_data *data)
4374 void *record = data->raw->data;
4376 if (likely(!event->filter) || filter_match_preds(event->filter, record))
4381 static void tp_perf_event_destroy(struct perf_event *event)
4383 ftrace_profile_disable(event->attr.config);
4386 static const struct pmu *tp_perf_event_init(struct perf_event *event)
4389 * Raw tracepoint data is a severe data leak, only allow root to
4392 if ((event->attr.sample_type & PERF_SAMPLE_RAW) &&
4393 perf_paranoid_tracepoint_raw() &&
4394 !capable(CAP_SYS_ADMIN))
4395 return ERR_PTR(-EPERM);
4397 if (ftrace_profile_enable(event->attr.config))
4400 event->destroy = tp_perf_event_destroy;
4402 return &perf_ops_generic;
4405 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4410 if (event->attr.type != PERF_TYPE_TRACEPOINT)
4413 filter_str = strndup_user(arg, PAGE_SIZE);
4414 if (IS_ERR(filter_str))
4415 return PTR_ERR(filter_str);
4417 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
4423 static void perf_event_free_filter(struct perf_event *event)
4425 ftrace_profile_free_filter(event);
4430 static int perf_tp_event_match(struct perf_event *event,
4431 struct perf_sample_data *data)
4436 static const struct pmu *tp_perf_event_init(struct perf_event *event)
4441 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4446 static void perf_event_free_filter(struct perf_event *event)
4450 #endif /* CONFIG_EVENT_TRACING */
4452 #ifdef CONFIG_HAVE_HW_BREAKPOINT
4453 static void bp_perf_event_destroy(struct perf_event *event)
4455 release_bp_slot(event);
4458 static const struct pmu *bp_perf_event_init(struct perf_event *bp)
4462 err = register_perf_hw_breakpoint(bp);
4464 return ERR_PTR(err);
4466 bp->destroy = bp_perf_event_destroy;
4468 return &perf_ops_bp;
4471 void perf_bp_event(struct perf_event *bp, void *data)
4473 struct perf_sample_data sample;
4474 struct pt_regs *regs = data;
4477 sample.addr = bp->attr.bp_addr;
4479 if (!perf_exclude_event(bp, regs))
4480 perf_swevent_add(bp, 1, 1, &sample, regs);
4483 static const struct pmu *bp_perf_event_init(struct perf_event *bp)
4488 void perf_bp_event(struct perf_event *bp, void *regs)
4493 atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
4495 static void sw_perf_event_destroy(struct perf_event *event)
4497 u64 event_id = event->attr.config;
4499 WARN_ON(event->parent);
4501 atomic_dec(&perf_swevent_enabled[event_id]);
4504 static const struct pmu *sw_perf_event_init(struct perf_event *event)
4506 const struct pmu *pmu = NULL;
4507 u64 event_id = event->attr.config;
4510 * Software events (currently) can't in general distinguish
4511 * between user, kernel and hypervisor events.
4512 * However, context switches and cpu migrations are considered
4513 * to be kernel events, and page faults are never hypervisor
4517 case PERF_COUNT_SW_CPU_CLOCK:
4518 pmu = &perf_ops_cpu_clock;
4521 case PERF_COUNT_SW_TASK_CLOCK:
4523 * If the user instantiates this as a per-cpu event,
4524 * use the cpu_clock event instead.
4526 if (event->ctx->task)
4527 pmu = &perf_ops_task_clock;
4529 pmu = &perf_ops_cpu_clock;
4532 case PERF_COUNT_SW_PAGE_FAULTS:
4533 case PERF_COUNT_SW_PAGE_FAULTS_MIN:
4534 case PERF_COUNT_SW_PAGE_FAULTS_MAJ:
4535 case PERF_COUNT_SW_CONTEXT_SWITCHES:
4536 case PERF_COUNT_SW_CPU_MIGRATIONS:
4537 case PERF_COUNT_SW_ALIGNMENT_FAULTS:
4538 case PERF_COUNT_SW_EMULATION_FAULTS:
4539 if (!event->parent) {
4540 atomic_inc(&perf_swevent_enabled[event_id]);
4541 event->destroy = sw_perf_event_destroy;
4543 pmu = &perf_ops_generic;
4551 * Allocate and initialize a event structure
4553 static struct perf_event *
4554 perf_event_alloc(struct perf_event_attr *attr,
4556 struct perf_event_context *ctx,
4557 struct perf_event *group_leader,
4558 struct perf_event *parent_event,
4559 perf_overflow_handler_t overflow_handler,
4562 const struct pmu *pmu;
4563 struct perf_event *event;
4564 struct hw_perf_event *hwc;
4567 event = kzalloc(sizeof(*event), gfpflags);
4569 return ERR_PTR(-ENOMEM);
4572 * Single events are their own group leaders, with an
4573 * empty sibling list:
4576 group_leader = event;
4578 mutex_init(&event->child_mutex);
4579 INIT_LIST_HEAD(&event->child_list);
4581 INIT_LIST_HEAD(&event->group_entry);
4582 INIT_LIST_HEAD(&event->event_entry);
4583 INIT_LIST_HEAD(&event->sibling_list);
4584 init_waitqueue_head(&event->waitq);
4586 mutex_init(&event->mmap_mutex);
4589 event->attr = *attr;
4590 event->group_leader = group_leader;
4595 event->parent = parent_event;
4597 event->ns = get_pid_ns(current->nsproxy->pid_ns);
4598 event->id = atomic64_inc_return(&perf_event_id);
4600 event->state = PERF_EVENT_STATE_INACTIVE;
4602 if (!overflow_handler && parent_event)
4603 overflow_handler = parent_event->overflow_handler;
4605 event->overflow_handler = overflow_handler;
4608 event->state = PERF_EVENT_STATE_OFF;
4613 hwc->sample_period = attr->sample_period;
4614 if (attr->freq && attr->sample_freq)
4615 hwc->sample_period = 1;
4616 hwc->last_period = hwc->sample_period;
4618 atomic64_set(&hwc->period_left, hwc->sample_period);
4621 * we currently do not support PERF_FORMAT_GROUP on inherited events
4623 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
4626 switch (attr->type) {
4628 case PERF_TYPE_HARDWARE:
4629 case PERF_TYPE_HW_CACHE:
4630 pmu = hw_perf_event_init(event);
4633 case PERF_TYPE_SOFTWARE:
4634 pmu = sw_perf_event_init(event);
4637 case PERF_TYPE_TRACEPOINT:
4638 pmu = tp_perf_event_init(event);
4641 case PERF_TYPE_BREAKPOINT:
4642 pmu = bp_perf_event_init(event);
4653 else if (IS_ERR(pmu))
4658 put_pid_ns(event->ns);
4660 return ERR_PTR(err);
4665 if (!event->parent) {
4666 atomic_inc(&nr_events);
4667 if (event->attr.mmap)
4668 atomic_inc(&nr_mmap_events);
4669 if (event->attr.comm)
4670 atomic_inc(&nr_comm_events);
4671 if (event->attr.task)
4672 atomic_inc(&nr_task_events);
4678 static int perf_copy_attr(struct perf_event_attr __user *uattr,
4679 struct perf_event_attr *attr)
4684 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
4688 * zero the full structure, so that a short copy will be nice.
4690 memset(attr, 0, sizeof(*attr));
4692 ret = get_user(size, &uattr->size);
4696 if (size > PAGE_SIZE) /* silly large */
4699 if (!size) /* abi compat */
4700 size = PERF_ATTR_SIZE_VER0;
4702 if (size < PERF_ATTR_SIZE_VER0)
4706 * If we're handed a bigger struct than we know of,
4707 * ensure all the unknown bits are 0 - i.e. new
4708 * user-space does not rely on any kernel feature
4709 * extensions we dont know about yet.
4711 if (size > sizeof(*attr)) {
4712 unsigned char __user *addr;
4713 unsigned char __user *end;
4716 addr = (void __user *)uattr + sizeof(*attr);
4717 end = (void __user *)uattr + size;
4719 for (; addr < end; addr++) {
4720 ret = get_user(val, addr);
4726 size = sizeof(*attr);
4729 ret = copy_from_user(attr, uattr, size);
4734 * If the type exists, the corresponding creation will verify
4737 if (attr->type >= PERF_TYPE_MAX)
4740 if (attr->__reserved_1 || attr->__reserved_2)
4743 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
4746 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
4753 put_user(sizeof(*attr), &uattr->size);
4758 static int perf_event_set_output(struct perf_event *event, int output_fd)
4760 struct perf_event *output_event = NULL;
4761 struct file *output_file = NULL;
4762 struct perf_event *old_output;
4763 int fput_needed = 0;
4769 output_file = fget_light(output_fd, &fput_needed);
4773 if (output_file->f_op != &perf_fops)
4776 output_event = output_file->private_data;
4778 /* Don't chain output fds */
4779 if (output_event->output)
4782 /* Don't set an output fd when we already have an output channel */
4786 atomic_long_inc(&output_file->f_count);
4789 mutex_lock(&event->mmap_mutex);
4790 old_output = event->output;
4791 rcu_assign_pointer(event->output, output_event);
4792 mutex_unlock(&event->mmap_mutex);
4796 * we need to make sure no existing perf_output_*()
4797 * is still referencing this event.
4800 fput(old_output->filp);
4805 fput_light(output_file, fput_needed);
4810 * sys_perf_event_open - open a performance event, associate it to a task/cpu
4812 * @attr_uptr: event_id type attributes for monitoring/sampling
4815 * @group_fd: group leader event fd
4817 SYSCALL_DEFINE5(perf_event_open,
4818 struct perf_event_attr __user *, attr_uptr,
4819 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
4821 struct perf_event *event, *group_leader;
4822 struct perf_event_attr attr;
4823 struct perf_event_context *ctx;
4824 struct file *event_file = NULL;
4825 struct file *group_file = NULL;
4826 int fput_needed = 0;
4827 int fput_needed2 = 0;
4830 /* for future expandability... */
4831 if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT))
4834 err = perf_copy_attr(attr_uptr, &attr);
4838 if (!attr.exclude_kernel) {
4839 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
4844 if (attr.sample_freq > sysctl_perf_event_sample_rate)
4849 * Get the target context (task or percpu):
4851 ctx = find_get_context(pid, cpu);
4853 return PTR_ERR(ctx);
4856 * Look up the group leader (we will attach this event to it):
4858 group_leader = NULL;
4859 if (group_fd != -1 && !(flags & PERF_FLAG_FD_NO_GROUP)) {
4861 group_file = fget_light(group_fd, &fput_needed);
4863 goto err_put_context;
4864 if (group_file->f_op != &perf_fops)
4865 goto err_put_context;
4867 group_leader = group_file->private_data;
4869 * Do not allow a recursive hierarchy (this new sibling
4870 * becoming part of another group-sibling):
4872 if (group_leader->group_leader != group_leader)
4873 goto err_put_context;
4875 * Do not allow to attach to a group in a different
4876 * task or CPU context:
4878 if (group_leader->ctx != ctx)
4879 goto err_put_context;
4881 * Only a group leader can be exclusive or pinned
4883 if (attr.exclusive || attr.pinned)
4884 goto err_put_context;
4887 event = perf_event_alloc(&attr, cpu, ctx, group_leader,
4888 NULL, NULL, GFP_KERNEL);
4889 err = PTR_ERR(event);
4891 goto err_put_context;
4893 err = anon_inode_getfd("[perf_event]", &perf_fops, event, O_RDWR);
4895 goto err_free_put_context;
4897 event_file = fget_light(err, &fput_needed2);
4899 goto err_free_put_context;
4901 if (flags & PERF_FLAG_FD_OUTPUT) {
4902 err = perf_event_set_output(event, group_fd);
4904 goto err_fput_free_put_context;
4907 event->filp = event_file;
4908 WARN_ON_ONCE(ctx->parent_ctx);
4909 mutex_lock(&ctx->mutex);
4910 perf_install_in_context(ctx, event, cpu);
4912 mutex_unlock(&ctx->mutex);
4914 event->owner = current;
4915 get_task_struct(current);
4916 mutex_lock(¤t->perf_event_mutex);
4917 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
4918 mutex_unlock(¤t->perf_event_mutex);
4920 err_fput_free_put_context:
4921 fput_light(event_file, fput_needed2);
4923 err_free_put_context:
4931 fput_light(group_file, fput_needed);
4937 * perf_event_create_kernel_counter
4939 * @attr: attributes of the counter to create
4940 * @cpu: cpu in which the counter is bound
4941 * @pid: task to profile
4944 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
4946 perf_overflow_handler_t overflow_handler)
4948 struct perf_event *event;
4949 struct perf_event_context *ctx;
4953 * Get the target context (task or percpu):
4956 ctx = find_get_context(pid, cpu);
4962 event = perf_event_alloc(attr, cpu, ctx, NULL,
4963 NULL, overflow_handler, GFP_KERNEL);
4964 if (IS_ERR(event)) {
4965 err = PTR_ERR(event);
4966 goto err_put_context;
4970 WARN_ON_ONCE(ctx->parent_ctx);
4971 mutex_lock(&ctx->mutex);
4972 perf_install_in_context(ctx, event, cpu);
4974 mutex_unlock(&ctx->mutex);
4976 event->owner = current;
4977 get_task_struct(current);
4978 mutex_lock(¤t->perf_event_mutex);
4979 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
4980 mutex_unlock(¤t->perf_event_mutex);
4987 return ERR_PTR(err);
4989 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
4992 * inherit a event from parent task to child task:
4994 static struct perf_event *
4995 inherit_event(struct perf_event *parent_event,
4996 struct task_struct *parent,
4997 struct perf_event_context *parent_ctx,
4998 struct task_struct *child,
4999 struct perf_event *group_leader,
5000 struct perf_event_context *child_ctx)
5002 struct perf_event *child_event;
5005 * Instead of creating recursive hierarchies of events,
5006 * we link inherited events back to the original parent,
5007 * which has a filp for sure, which we use as the reference
5010 if (parent_event->parent)
5011 parent_event = parent_event->parent;
5013 child_event = perf_event_alloc(&parent_event->attr,
5014 parent_event->cpu, child_ctx,
5015 group_leader, parent_event,
5017 if (IS_ERR(child_event))
5022 * Make the child state follow the state of the parent event,
5023 * not its attr.disabled bit. We hold the parent's mutex,
5024 * so we won't race with perf_event_{en, dis}able_family.
5026 if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
5027 child_event->state = PERF_EVENT_STATE_INACTIVE;
5029 child_event->state = PERF_EVENT_STATE_OFF;
5031 if (parent_event->attr.freq) {
5032 u64 sample_period = parent_event->hw.sample_period;
5033 struct hw_perf_event *hwc = &child_event->hw;
5035 hwc->sample_period = sample_period;
5036 hwc->last_period = sample_period;
5038 atomic64_set(&hwc->period_left, sample_period);
5041 child_event->overflow_handler = parent_event->overflow_handler;
5044 * Link it up in the child's context:
5046 add_event_to_ctx(child_event, child_ctx);
5049 * Get a reference to the parent filp - we will fput it
5050 * when the child event exits. This is safe to do because
5051 * we are in the parent and we know that the filp still
5052 * exists and has a nonzero count:
5054 atomic_long_inc(&parent_event->filp->f_count);
5057 * Link this into the parent event's child list
5059 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
5060 mutex_lock(&parent_event->child_mutex);
5061 list_add_tail(&child_event->child_list, &parent_event->child_list);
5062 mutex_unlock(&parent_event->child_mutex);
5067 static int inherit_group(struct perf_event *parent_event,
5068 struct task_struct *parent,
5069 struct perf_event_context *parent_ctx,
5070 struct task_struct *child,
5071 struct perf_event_context *child_ctx)
5073 struct perf_event *leader;
5074 struct perf_event *sub;
5075 struct perf_event *child_ctr;
5077 leader = inherit_event(parent_event, parent, parent_ctx,
5078 child, NULL, child_ctx);
5080 return PTR_ERR(leader);
5081 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
5082 child_ctr = inherit_event(sub, parent, parent_ctx,
5083 child, leader, child_ctx);
5084 if (IS_ERR(child_ctr))
5085 return PTR_ERR(child_ctr);
5090 static void sync_child_event(struct perf_event *child_event,
5091 struct task_struct *child)
5093 struct perf_event *parent_event = child_event->parent;
5096 if (child_event->attr.inherit_stat)
5097 perf_event_read_event(child_event, child);
5099 child_val = atomic64_read(&child_event->count);
5102 * Add back the child's count to the parent's count:
5104 atomic64_add(child_val, &parent_event->count);
5105 atomic64_add(child_event->total_time_enabled,
5106 &parent_event->child_total_time_enabled);
5107 atomic64_add(child_event->total_time_running,
5108 &parent_event->child_total_time_running);
5111 * Remove this event from the parent's list
5113 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
5114 mutex_lock(&parent_event->child_mutex);
5115 list_del_init(&child_event->child_list);
5116 mutex_unlock(&parent_event->child_mutex);
5119 * Release the parent event, if this was the last
5122 fput(parent_event->filp);
5126 __perf_event_exit_task(struct perf_event *child_event,
5127 struct perf_event_context *child_ctx,
5128 struct task_struct *child)
5130 struct perf_event *parent_event;
5132 perf_event_remove_from_context(child_event);
5134 parent_event = child_event->parent;
5136 * It can happen that parent exits first, and has events
5137 * that are still around due to the child reference. These
5138 * events need to be zapped - but otherwise linger.
5141 sync_child_event(child_event, child);
5142 free_event(child_event);
5147 * When a child task exits, feed back event values to parent events.
5149 void perf_event_exit_task(struct task_struct *child)
5151 struct perf_event *child_event, *tmp;
5152 struct perf_event_context *child_ctx;
5153 unsigned long flags;
5155 if (likely(!child->perf_event_ctxp)) {
5156 perf_event_task(child, NULL, 0);
5160 local_irq_save(flags);
5162 * We can't reschedule here because interrupts are disabled,
5163 * and either child is current or it is a task that can't be
5164 * scheduled, so we are now safe from rescheduling changing
5167 child_ctx = child->perf_event_ctxp;
5168 __perf_event_task_sched_out(child_ctx);
5171 * Take the context lock here so that if find_get_context is
5172 * reading child->perf_event_ctxp, we wait until it has
5173 * incremented the context's refcount before we do put_ctx below.
5175 raw_spin_lock(&child_ctx->lock);
5176 child->perf_event_ctxp = NULL;
5178 * If this context is a clone; unclone it so it can't get
5179 * swapped to another process while we're removing all
5180 * the events from it.
5182 unclone_ctx(child_ctx);
5183 update_context_time(child_ctx);
5184 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
5187 * Report the task dead after unscheduling the events so that we
5188 * won't get any samples after PERF_RECORD_EXIT. We can however still
5189 * get a few PERF_RECORD_READ events.
5191 perf_event_task(child, child_ctx, 0);
5194 * We can recurse on the same lock type through:
5196 * __perf_event_exit_task()
5197 * sync_child_event()
5198 * fput(parent_event->filp)
5200 * mutex_lock(&ctx->mutex)
5202 * But since its the parent context it won't be the same instance.
5204 mutex_lock_nested(&child_ctx->mutex, SINGLE_DEPTH_NESTING);
5207 list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
5209 __perf_event_exit_task(child_event, child_ctx, child);
5211 list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
5213 __perf_event_exit_task(child_event, child_ctx, child);
5216 * If the last event was a group event, it will have appended all
5217 * its siblings to the list, but we obtained 'tmp' before that which
5218 * will still point to the list head terminating the iteration.
5220 if (!list_empty(&child_ctx->pinned_groups) ||
5221 !list_empty(&child_ctx->flexible_groups))
5224 mutex_unlock(&child_ctx->mutex);
5229 static void perf_free_event(struct perf_event *event,
5230 struct perf_event_context *ctx)
5232 struct perf_event *parent = event->parent;
5234 if (WARN_ON_ONCE(!parent))
5237 mutex_lock(&parent->child_mutex);
5238 list_del_init(&event->child_list);
5239 mutex_unlock(&parent->child_mutex);
5243 list_del_event(event, ctx);
5248 * free an unexposed, unused context as created by inheritance by
5249 * init_task below, used by fork() in case of fail.
5251 void perf_event_free_task(struct task_struct *task)
5253 struct perf_event_context *ctx = task->perf_event_ctxp;
5254 struct perf_event *event, *tmp;
5259 mutex_lock(&ctx->mutex);
5261 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
5262 perf_free_event(event, ctx);
5264 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
5266 perf_free_event(event, ctx);
5268 if (!list_empty(&ctx->pinned_groups) ||
5269 !list_empty(&ctx->flexible_groups))
5272 mutex_unlock(&ctx->mutex);
5278 inherit_task_group(struct perf_event *event, struct task_struct *parent,
5279 struct perf_event_context *parent_ctx,
5280 struct task_struct *child,
5284 struct perf_event_context *child_ctx = child->perf_event_ctxp;
5286 if (!event->attr.inherit) {
5293 * This is executed from the parent task context, so
5294 * inherit events that have been marked for cloning.
5295 * First allocate and initialize a context for the
5299 child_ctx = kzalloc(sizeof(struct perf_event_context),
5304 __perf_event_init_context(child_ctx, child);
5305 child->perf_event_ctxp = child_ctx;
5306 get_task_struct(child);
5309 ret = inherit_group(event, parent, parent_ctx,
5320 * Initialize the perf_event context in task_struct
5322 int perf_event_init_task(struct task_struct *child)
5324 struct perf_event_context *child_ctx, *parent_ctx;
5325 struct perf_event_context *cloned_ctx;
5326 struct perf_event *event;
5327 struct task_struct *parent = current;
5328 int inherited_all = 1;
5331 child->perf_event_ctxp = NULL;
5333 mutex_init(&child->perf_event_mutex);
5334 INIT_LIST_HEAD(&child->perf_event_list);
5336 if (likely(!parent->perf_event_ctxp))
5340 * If the parent's context is a clone, pin it so it won't get
5343 parent_ctx = perf_pin_task_context(parent);
5346 * No need to check if parent_ctx != NULL here; since we saw
5347 * it non-NULL earlier, the only reason for it to become NULL
5348 * is if we exit, and since we're currently in the middle of
5349 * a fork we can't be exiting at the same time.
5353 * Lock the parent list. No need to lock the child - not PID
5354 * hashed yet and not running, so nobody can access it.
5356 mutex_lock(&parent_ctx->mutex);
5359 * We dont have to disable NMIs - we are only looking at
5360 * the list, not manipulating it:
5362 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
5363 ret = inherit_task_group(event, parent, parent_ctx, child,
5369 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
5370 ret = inherit_task_group(event, parent, parent_ctx, child,
5376 child_ctx = child->perf_event_ctxp;
5378 if (child_ctx && inherited_all) {
5380 * Mark the child context as a clone of the parent
5381 * context, or of whatever the parent is a clone of.
5382 * Note that if the parent is a clone, it could get
5383 * uncloned at any point, but that doesn't matter
5384 * because the list of events and the generation
5385 * count can't have changed since we took the mutex.
5387 cloned_ctx = rcu_dereference(parent_ctx->parent_ctx);
5389 child_ctx->parent_ctx = cloned_ctx;
5390 child_ctx->parent_gen = parent_ctx->parent_gen;
5392 child_ctx->parent_ctx = parent_ctx;
5393 child_ctx->parent_gen = parent_ctx->generation;
5395 get_ctx(child_ctx->parent_ctx);
5398 mutex_unlock(&parent_ctx->mutex);
5400 perf_unpin_context(parent_ctx);
5405 static void __cpuinit perf_event_init_cpu(int cpu)
5407 struct perf_cpu_context *cpuctx;
5409 cpuctx = &per_cpu(perf_cpu_context, cpu);
5410 __perf_event_init_context(&cpuctx->ctx, NULL);
5412 spin_lock(&perf_resource_lock);
5413 cpuctx->max_pertask = perf_max_events - perf_reserved_percpu;
5414 spin_unlock(&perf_resource_lock);
5416 hw_perf_event_setup(cpu);
5419 #ifdef CONFIG_HOTPLUG_CPU
5420 static void __perf_event_exit_cpu(void *info)
5422 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
5423 struct perf_event_context *ctx = &cpuctx->ctx;
5424 struct perf_event *event, *tmp;
5426 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
5427 __perf_event_remove_from_context(event);
5428 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry)
5429 __perf_event_remove_from_context(event);
5431 static void perf_event_exit_cpu(int cpu)
5433 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
5434 struct perf_event_context *ctx = &cpuctx->ctx;
5436 mutex_lock(&ctx->mutex);
5437 smp_call_function_single(cpu, __perf_event_exit_cpu, NULL, 1);
5438 mutex_unlock(&ctx->mutex);
5441 static inline void perf_event_exit_cpu(int cpu) { }
5444 static int __cpuinit
5445 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
5447 unsigned int cpu = (long)hcpu;
5451 case CPU_UP_PREPARE:
5452 case CPU_UP_PREPARE_FROZEN:
5453 perf_event_init_cpu(cpu);
5457 case CPU_ONLINE_FROZEN:
5458 hw_perf_event_setup_online(cpu);
5461 case CPU_DOWN_PREPARE:
5462 case CPU_DOWN_PREPARE_FROZEN:
5463 perf_event_exit_cpu(cpu);
5467 hw_perf_event_setup_offline(cpu);
5478 * This has to have a higher priority than migration_notifier in sched.c.
5480 static struct notifier_block __cpuinitdata perf_cpu_nb = {
5481 .notifier_call = perf_cpu_notify,
5485 void __init perf_event_init(void)
5487 perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
5488 (void *)(long)smp_processor_id());
5489 perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_ONLINE,
5490 (void *)(long)smp_processor_id());
5491 register_cpu_notifier(&perf_cpu_nb);
5494 static ssize_t perf_show_reserve_percpu(struct sysdev_class *class, char *buf)
5496 return sprintf(buf, "%d\n", perf_reserved_percpu);
5500 perf_set_reserve_percpu(struct sysdev_class *class,
5504 struct perf_cpu_context *cpuctx;
5508 err = strict_strtoul(buf, 10, &val);
5511 if (val > perf_max_events)
5514 spin_lock(&perf_resource_lock);
5515 perf_reserved_percpu = val;
5516 for_each_online_cpu(cpu) {
5517 cpuctx = &per_cpu(perf_cpu_context, cpu);
5518 raw_spin_lock_irq(&cpuctx->ctx.lock);
5519 mpt = min(perf_max_events - cpuctx->ctx.nr_events,
5520 perf_max_events - perf_reserved_percpu);
5521 cpuctx->max_pertask = mpt;
5522 raw_spin_unlock_irq(&cpuctx->ctx.lock);
5524 spin_unlock(&perf_resource_lock);
5529 static ssize_t perf_show_overcommit(struct sysdev_class *class, char *buf)
5531 return sprintf(buf, "%d\n", perf_overcommit);
5535 perf_set_overcommit(struct sysdev_class *class, const char *buf, size_t count)
5540 err = strict_strtoul(buf, 10, &val);
5546 spin_lock(&perf_resource_lock);
5547 perf_overcommit = val;
5548 spin_unlock(&perf_resource_lock);
5553 static SYSDEV_CLASS_ATTR(
5556 perf_show_reserve_percpu,
5557 perf_set_reserve_percpu
5560 static SYSDEV_CLASS_ATTR(
5563 perf_show_overcommit,
5567 static struct attribute *perfclass_attrs[] = {
5568 &attr_reserve_percpu.attr,
5569 &attr_overcommit.attr,
5573 static struct attribute_group perfclass_attr_group = {
5574 .attrs = perfclass_attrs,
5575 .name = "perf_events",
5578 static int __init perf_event_sysfs_init(void)
5580 return sysfs_create_group(&cpu_sysdev_class.kset.kobj,
5581 &perfclass_attr_group);
5583 device_initcall(perf_event_sysfs_init);